A health view of asbestos: an annotated literature collection--1960-1974.

Asbestos is everywhere! Possessing an enigmatic history of incalculable risks and benefits asbestos now reaches into our daily lives by myriad means. Long used in relatively small amounts for centuries asbestos uses and demands have gained momentously in our modern industrialized society. In the last 60 years, global use of asbestos has increased more than 100-fold from 30,000 tons to four million tons. Asbestos is widely stated to be a constituent in at least 3,000 manufactured products. Industrial usefulness of asbestos stems particularly from its natural properties nonflammability, flexibility, tensile strength, low density, resistance to acids and alkalies, and high electrical resistivity. Resultantly, widespread dissemination in the total environment is revealed by asbestos fibers in the air we breathe, the food and beverages we consume, and the water we drink. Asbestos thus no longer represents singly an occupational hazard but a menacing and growing problem of environmental pollution threatening everyone. Accordingly, interest in the health aspects of


Introduction
Asbestos is everywhere! Possessing an enigmatic history of incalculable risksand benefitsasbestos now reaches into our daily lives by myriad means. Long used in relatively small amounts for centuries asbestos uses and demands have gained momentously in our modern industrialized society. In the last 60 years, global use of asbestos has increased more than 100-foldfrom 30,000 tons to four million tons. Asbestos is widely stated to be a constituent in at least 3,000 manufactured products. Industrial usefulness of asbestos stems particularly from its natural properties nonflammability, flexibility, tensile strength, low density, resistance to acids and alkalies, and high electrical resistivity.
Resultantly, widespread dissemination in the total environment is revealed by asbestos fibers in the air we breathe, the food and beverages we consume, and the water we drink. Asbestos thus no longer represents singly an occupational hazard but a menacing and growing problem of environmental pollution threatening everyone.
Accordingly, interest in the health aspects of *Work supported by the Toxicology Information Program,  1974(Environ. Health Perspect, No. 9: 1974. Historically, significant asbestos literature, in addition to the above proceedings, include A. J. Lanza's Silicosis and Asbestosis, Oxford Univ. Press (1938), the National Academy of Sciences' Asbestos. The Need For and Feasibility of Air Pollution Controls (1971), and the National Institute for Occupational Safety and Health's Criteria for a Recommended Standard .... Occupational Exposure to Asbestos (1972). The International Agency for Research on Cancer (IARC) published in 1973 a critical Monograph on Asbestos which permits an evaluation of the carcinogenic risk to man (IARC Monographs on the Evaluation of Carcinogenic Risk to Man. Some Inorganic and Organometallic Compounds. Volume 2). Geographical, mining, production, and use data are presented in the United States Mineral Resources Geological Survey Professional Paper 820 (1973)  The asbestos literatureas is most published literatureis scattered throughout the world in diverse sources. Recently the Biomedical Sciences Section began building a computerized data base on asbestos for the period 1960 into 1974 emphasizing hazards and clinical aspects. Entries' were expediently selected to represent a cross section of the total asbestos literature and to complement this issue (No. 9) of Environmental Health Perspectives. These 549 records each consist of author(s), title, journal, citation, factual abstract, and keyterms. Author, keyterm, and permuted title indexes serve as entry ports into the record file. The' listing is arranged by yearthe most current year firstand alphabetically within each year by author. The number of references in our collection as categorized by year are: 15/1974 73/1973 49/1972 96/1971 83/1970 36/1969 41/1968 29/1967 13/1966 59/1965 23/1964 6/1963 11/1962 9/1961 6/1960 Original papers were annotated whenever possible; some few were taken from abstract journals. Annotations reflect author's remarks and conclusions as they appeared in the literature. Our computerized asbestos collection will be updated on a routine basis, with periodic publication and dissemination. (1974) The Food and Druq Administration (FDA) is expected to ask the Fnvironnental protection Agency (EPA) to clarify its decision orohibiting use of the Duluth, Minnesota water supply, since EPA lacked information about the asbestos content of other cities water supplies. The FDA noted that the water supply in San Francisco contains more asbestos naturally than does the water in Duluth. ASBESTOS; EMYTRONMENTAL COWTAMINATION; STANDARDS <4> Anonymous, Asbestos, Food Chen. Mews, 16(8): S0-s1 (1974) .
The Commissioner of the Food and Drug Administration (FDA) requested clarification of the ban by the Environmental Protection Agency (EPA), of the use of the Duluth water supply for human consumption. The Agency has been informed that the San Francisco water supply is naturally contaminated with asbestos fibers from serpentine rock and that the majority of asbestos fibers found in the water supply of Duluth, Minnesota is short (Su in length), whereas fibers implicated in the development of malignancy are very long. The ?PA is questioned about future plans to reclassify water supplies of other cities, since it is PDA's responsibility to enforce the ruling. ASBESTOS; INGESTION; ENTIRONMENTAL CONTAMINATION; STANDARDS; HUMAN (5>. Anonymous, Asbestos, Food Chem. News, 16(9): 2 (1974).
No increase in cancer deaths was shown in review of death certificates by the MCI of Minnesota residents whose water supply was contaminated by asbestos fibers from a taconite mill. Researchers agree that it is to early to make a positive decision on the effects of asbestos fibers because of the long latency period (20-40 years) (19748 The Food and Drug Administration's proposed optical method of detecting asbestos was critized by Malcolm Poss, the Environmental nefense rund and the Center for Science in the Public Interest as being insufficient to identify small amounts of amphiboles and chrysotile in commercial talcs. Maicol 'Ross recommended the follovinq procedure: optical screening to identify coarse grained primary anphiboles and chrysotile if present as fibers longer than 10 u; x-ray powder diffraction examination if the amount of asbestos present is greater than one weight percent; and el4ctron microscopy, electron diffraction, and qnergy dispersive semi-quantitative chemical analysis to make an absolute mineralogical identification. ASBESTOS; ANALYSIS; STANDARDS; CRRYSOTILF; ENVIRONMENTAL CONTAMINATTON <> Anonymous, Asbestos, Food Chem. Wevs, 16(2): 2 (1974) The Asbestos Research Council stated in n report to the FDA that, according to research by TPA Industrial Products, Ltd., asbestos filters used for beer processing did not introduce "any additional asbestos fibers" in to the beer. should have made a strong, affireative statement for the continued use of asbestos filters according to some firms. The firms noted that in some instances asbestos filters are being replaced by micro-glass filters which may prove to be even more dangerous.
ASBESTOS; STANDARDS; FOOD COWTAMIWATION; ASBESTOS FILTERS <9> Anonymous, Wev asbestos detection alternatives suggested to FDA., Pest. Chem. Wevs, 2(7): 8-9 (19748 . The Cosmetic, Toiletry and Fragrance Association (CTFA) called the FDX's proposed optical metbod for detecting asbestos in talc "premature" and suggested deferment until: (1) the standard deviation of the proposed test method is determined; (2) an evaluation is done to validate the assumption that a single milligram sample is statistically representative of the lot; (3) a re-evaluation of the cost and practicality of the test method is accomplished; and (4) and intensive search is made for a more reliable and practical test method. Alternative methods suggested to detect chrysotile and tremolite in talc were: optical microscopic methods, x-ray step scanning, x-ray scanning optical microscopy, x-ray scanning, differential thermal analysis, scanninq electron microscopy and transmission electron microscopy electron diffract lon. Rice often is coated with glucose and talc to improve the appearance of the rice kernel. Due to the potentially carcinogenic nature of asbestos, the FDA requires that asbestos-free talc be used. The Rice millers Association has urged the FDA to ban the coating of milled rice because it conceals the true nature of the rice kernal, adds to the cost of the rice end must be washed of f before use, further reducing the nutritive value.  NPA-680/2-74-01'5: p. 12 (1974).
Adequate methods are available for measuring the emission of the hazardous air pollutants, mercury and beryllium. Nowever, the electron microscope technique for determing asbestos in filtered ambient air samples is not rapid enough to support an emission standard. work Is in progress to find an adequate technique for measuring source emissions of asbestos.
Most routine measurements of airborne asbestos concentrations have been made by the midget impithger metbod which has relatively loy efficiency for fiber collection and prinarily gives a particle (dustl count. Fiber concentration is probably more important with respect to disease and the membrane filter method is more efficient in determining fiber count. No correlation was found among 87 counts made by both the paired midget impinger and membrane filter methods and no conversion factor between the two could be calculated. Until the relationshtps can be ascertained, safety standards should continue to be based on dust counts for which much epideamological support exists, rather than fiber counts. ASBESTOS; ANALYSIS; STANDARDS; ENVIRONMEPNTAL SAMPLING <13> Libshitz, R.I.; Wershba, M.S.; Atkinson, G.W.; Southard, R.E., Asbestosis and carcinoma of the larynx, 3. Amer. Med. Assoc.,228(12): 1571-1'572 (1974) A possible association between asbestosis and carcinoma of the larynx is suggested in three case histortes of men employed in the asbestos industry.
All had chest x-rays consistent with asbestosis and had smoced at least a pack of cigarettes a day for a considerable length of time. All three were found to have epidermoid carcinomas of the larynx. No precise causative role could be assigned to asbestos and a synergistic effect of cigarette smoking and asbestos exposure was possible. Because high concentrations of asbestos-like fibers were found in the drinking water of Duluth, Minn. a study was made to determine if the fibers were related to cancer mortality. Data were abstracted from death certificates of all persons vho died of cancer in the U.S. from 1950 to 1969 and the number of deaths due to cancer in whites was tabulated accordinq to age, sex, and five-year intervals. The age adjusted cancer death rates for Duluth were also tabulated and a comparison made with those from the state of ninnesota and Pennepin County. Of 21 cancer sites in the study, only mortality rates from rectal cancer increased signficantly (P < .01) with time and especially in the most recent S year period. Uased on other studies from occupational exposure to asbestos the death rate from cancer of the esophagus and stomach should have increased to a greater degree than that for the rectum but did not. There were no significant excess deaths from cancer among persons under 20 years of age. A longer follow-up study is necessary to determine if a relationship exists between cancer and asbestos in the Duluth drinking water. ASBESTOS; CANCER; CANCEP MORTALITY; rNTIROlNMNTAL CONTAMINATION; INGESTION; NOW-OCCUPATIONAL EXPOSURE Environmental Health Perspectives (15> McDonald,J.C.;Becklake,R.R.;Gibbs,G.W.;McDonald,A.D.;Sossiter,C. ., The health of chrysotile asbestos mine and mill workers of Quebec., Arch. Environ. Wealth,28(2): 61-68 (1974).
Studies pf respiratory symptoms and function, roentgenographic changes, and mortality were made in relation to dust exposure in the Quebec chrysotile industry. A total dust exposure index for each worker was calculated based on time and extent of dust exposure. An examination of the mortality of the workers showed no cause of death (except pneamoniosis) with a rate above that of the general population. Fxcess death from respiratory cancers was, at most, 50S above expectation, based on age-specific rates for Quebec and the mining region. Breathlessness on exercise, diminshed inspiratory capacity, parenchymal anti pleural changes, and respiratory disease mortality were related to dust exposure and to each other. Saftey standards for the asbestos industries should be based on dose-response relationships established by sound epidemiologica 1 studies.

ASBESTOS; CRRYSOTTLE; OCCUPATIOWAL EXPOSURE;
FIBROSIS; X-RAy; RtSOTMELIOMA; STANDARDS; PWEUMRCOWTOSIS; YT'TILATORY DETECTS; HUMAN <16> Anonysous, Asbestos., Nat. Safety Sews, 108 (3): 156-160 (1973) The U.S. Bureau of Mines found the concentration of asbestos fibers in asbestos mines to be low, but well above 5 fibers/ml of air in asbestos mills. The Bureau's report concluded that "some operators are adequately controlling the amount of asbestos in the breathing zone of workmen; however, many are using inadequate control measures and practices, which result in workmen being exposed to asbestos fiber concentrations above 5 fibers/ml"; Ott ts believed that operators of most mills and mines should be able to meet a 'five fibers/ml of fibers greater than five um in length' standard" by followinq proper practices. ASBESTOS; STANDARDS; OCCUPATIOWAL EXPOSURE; ASBESTOS I II ING <17> Anonymous, Rain gets request to ban asbestos cement water pipes., Pest. Chean. ews, 2(2): 12, (1973).
The Center for Sdence in the Public Interest has petitioned the Environmental Protection Agency and 6 Congressmen to request a ban on the use of asbestos cement pipe in water systems. The Center said that "there is ample reason to believe that ingestion of the major varities of asbestos leads to increased risk of gastrointestinal cancer." ASBESTOS; CANCER; STANDARDS; ENWIROSNESTAL COST AM IS ATIOS; INGESTION Administration's proposed optical method would be time conmtaing and expensive, and that a dispersion staining method would be more feasible. McCrone discussed alternatitve methods, concluding that the scanning electron microscope was an "overrated tool" and a polarizing light microscope was useless for very small asbestos fibers; a diffraction method must be used for detecting these small fibers. The firm stated that most laboratories lack the equipment or skilled analysts necessary for each method, and tend to-use available tools and skills instead.
The Food and Drug Administration detained 15,000 bags of dried lima beans that were contaminated with asbestos following a shipboard accident. The owners were unable to recondition the beans and shipped them to another country.
ASBESTOS; SOW-OCCUPATIONAL EXPOSURE; FOOD COSTAHISATIOS <20> Anonymous, EPA's Korp says asbestos in pesticides is not a health hazard., Pest. Chem. Sews, 1(52): 14 relationship between the inhalation of asbestos dust and cancers of the lung, pleura, and peritoneum. The carcinogenic risk and action are related to the size and shape of the fibers vh.ich are most danqerous vher straight and fine. The greatest risk is ampnq workers in asbestos industries; the general public usually is not at risk, even in urban areas.
Infinitely greater cancer risk from occupational asbestos exposure is evident in heavy smokers. Unfortunately, 20-40 years may elapse tetween asbestos exposure and development of cancer. The Food and Drug Administration took three actions relative to asbestos contamination in food and drugs: (1) a request for all information available on the effects of asbestos injection through drug use, (2) published for comment a petition from the Center for Science in the Public Interest and the Environmental Defense rund to prohibit asbestos residues in food and drugs, and (3) presented plans to reduce asbestos residues in food and drugs to minimum detectable levels by present tdchnology. The plans are to establish a more accu4tte standard test method for detecting asbestos fibiks in food-grade talc and to require that no'asbestos filter be used in the manufacture of injectable dregs unless no acceptable alternative is available.
Enventions told the Food and Drug Administration that the limited resolvinq power of optical microscopes reduced the capability of detecting small asbestos fibers that occur in talc. The FDA-proposed optical method should be replaced by high resolution scanning electron microscopy (SEI), even though the SEM method could not "positively identify a fiber as being asbestos." In contrast, Engelhard Minerals t Chemicals said that the FDA's proposed method was "a technically sound and fundamentally applicable method for the optical identificiation of and discrimination between the listed amphibole minerals, chrysottle, and talc." However, the method is time consuming, costly, and beyond the capabilities of most field engineer personnel.
The risk of malignant neoplasta related to occupational asbestos exposure is high, even when no radiological evidence of pulmonary fibrosts exists. Exposure through environmental pollution and other non-occupational sources can be significant as evidenced by the high Incidence of asbestos bodies and fibers in the lungs of urban dwell ers.
The image analyzing microscope (TAM) method of identifying and quantifying airborne 'asbestos includes: (1) a modified sampling method for uniform and representative particle collecting; (2) ashing of the specimen to eliminate the collection filter and oxidizable particles which interfere in analysis; and (3) the use of a refractive index liquid to distinguish asbestos varticles frow other fibrous materials, thus enabling counts of asbestos only. Since 50 -100 fields can be mapped and measured in a short time and since the total number of Farticles are counted in each field, this method minimizes both experimental time usage and error.
Talcs for commercial or Industrial uses are usually contaminated vith asbestos minerals due to the similarity in their geological processes. Both talc and asbestos produce various fibrosing conditions; both asbestos and asbestos-contaminated talc are occupationally associated with excess cancer mortality. No scientific evidence df carcinogenicity of talc has been documented; however, talc particles have been found in normal tissue of women with carcinomas but with no occupational exposure to talc or asbestos. Since talcs are used in a multitude of ways whlch can lead to widespread inhalation, ingestion and other exposures, controlled experimental animals studies are recommended to ascertain the carcinogenicity of pure talc. The   Asbestos workers in Singapore. A clinical, functional, and radiological survey., Arch. Entiron. Health,26(6): 290-293 (1973).
A group of workers in a Singapore asbestos sheet and pipe factory were examined for evidence of radiological and clinical respiratory abnormalities. This group of 114 workers was especially useful for a study of "early" or "mild" asbestosts because of relatively young average age (32) and average exposure time (4 years). Chext x-rays were not helpful in identifying likely "asbestotic" subjects.
The presence of crepitations and a disproportionate reduction in forced vital capacity, but not forced expiratory volume at 1 second, were related to exposure time. Other clinical tests such as loose cough together with the function tests were used to define three qroups within the, worker population: normal, presumptive diagnosis of chronic bronchitis, and presumptive diagnosis of mild respiratory abnormality consistent with "mild" or "early" asbestos is.
ASBESTOS; BROWCHITTS; ASBESTOSIS; OCCUPATIONAL, EXPOSURE; VEYTILATORY DEFECTS; RESPIRATORY DISIBASE; DIAGNOSIS; HUMAN <33> Cohen, D., Ferromagnetic contamination in the lungs and other organs of the human body., Science, 180: 745-748 (19731. The ferromagnetic nature of asbestos particles may possibly be useful in detecting and localizing them in the human body. Following the application of an external magnetic field to the body, the. steady magnetic field generated by the magnetixed particles can be mapped thus revealing the distribution of these particles in the body.
Trace metals associated with asbestos fibers have not been found responsible for' the fibrogenic properties of asbestos. Trace metals may, however, modify biological responses to asbestos, and further research should elucidate more fully the mechanism of action.
In 1348 men occupationally exposed to asbestos for an average of 25 years, mortality after age 65 was 14H.7 higher than in the counterpart male population of the United States; the maior cause of death was respiratory cancer and respiratory disease. Using time-weighted calculations of exposure, respiratory cancer rates ranged from 1.7 times the expected for men with less than 125 million particles per cubic foot (mppcf)-years exposure to 5.6 times the expected for men with 7S0 or more mppcf-years exposure.
Among 1,348 men who retired from asbestos industries between 1941 and 1967, those exposed only to chryostile had a respiratory cancer mortality rate of 2.4 times greater than expected; the cancer mortality rate in men exposed to both chrysotile and crocidolite was 5.3 times higher. The respiratory cancer risk for workers exposed to chrysotile was 1.4 times greater than expected, whereas the hazard related to both chrysotile and crocidolite asbestos exposure was 6.1 times higher.  Morgan, A.; Walsh, N., Studies on the deposition of inhaled fibrous material in the respiratory tract of the rat and its subsequent clearance using radioactive tracer techniques., Environ. Res., 6: 180-201 (1973).
Albino rats were exposed to an aerosol containing 10 mq crocidolite/l at a rate of 3 I/min for 42 or 90 minutes. Approximately 35% of the inhaled asbestos was depositedinitially, 50% of this accumulated in the lower respiratory tract, declininq by 27W within 30 days following exposure. Dust deposited in the upper respiratory tract wak removed rapidly via the esophoqus within 30 minutes after exposure. Most of the asbestos traversing the gastrointestinal tract passed through the stomach to the small intestine within 1 hr of exposure.
The Michael Williams Memorial Lecture concerning asbestos reviewed the folloving topics: (1) historical aspects and processes within the industry; (2) factors influencing incidence of asbestos cancer; (3) lung carcinomas (comparisons of recent surveys of asbestos workers, relation of carcinogenicity to length of exposure, to sex and to cofactors); (4) mesothelial tumors (link with asbestos exposure, type of fiber, dose of dust, duration of exposure, and sex, cofactors, and rising incidence of mesotheliomas in the United Kingdom) (5) pathogenesis; and (6)  The Philadelphia Board of Health adopted the following regulations to protect construction workers and the public from potentially hazardous asbestos fibers: (1) prohibits use of asbestos spray; (2) limits exposure to inhalation of airborne fibers to 5 fibers/milliliter of air; (3) prohibits occupancy of any building if the concentration of fibers exceeds 0.5 fibers/milliter of air averaged over any 8 hour period; and (4) compulsory monitoring for asbestos fibers. Presumably regulations were adopted because voluntary controls were not deemed effective. Crysotile concentrations in the lungs of 9 fiber glass workers ranged from 1 to 45% of the total fiber content, with an average of 17%. Five of 8 non-occupationally exposed female residents had chrysotile lung concentrations of 3 to 12% with lymph node levels of 3 to 9% -both tissues averaged 6%. No  Gross, P.; Harley, R.A., The locus of pathogenicity of asbestos dust., Arch. Environ. Health, 27: 240-242 (1973).
When polyfilamentous asbestos fibers are converted to monofilamentous structures, either by heating to 1,000 C, by grinding to a fiber length less than Su, or by chemically cementing the fibrils together, pethogenicity is reduced. Resultantly, the theoretical locus of pathoqenicity of asbestos dust particles resides in the polyfilamentous structure.
Inttapleural injection of Canadian crysotile, amosite and crocidolite produced a significant number of differentiated intrathoracic tumors in rats, and undifferentiated sarcomas in hamsters. of 35 tumors in rats, 25 were fibrosarcomas, S mesotheliomas, 3 rhabdomyosarcomas, 2 osteogentc sarcomas or fibrosarcomas with bone formation, and 1 a fibroliposarcona. Addition to or removal of trace metals from asbestos dust caused no difference in tumor production. The IN VITRO biological effects of asbestos on guinea pig peritoneal macrophages vary with the type and state of asbestos used. Cell-damage as measured by oxygen respiration or nigrosine staining was greatest with chrysotile B (98% of cells damaged) and decreased through the series chrysotile A greater than anthopbyllite greater than crocidolite qreater than amosite (38% of cells damaged). Dry grinding of the asbestos dust to reduce fiber length reduced the toxicity of crocidolite and amosite only. Reating chryostile A to a temperature of 600 degrees C rearranges the crystal structure and increases the cytotoxicity with respect to oxygen evolution. The physical nature of the fibers may be responsible for their rI vITo effect, with the rigid, dense crocidolite fibers penetrating to the pleura more easily than the curly fibers of other asbestos types, particularly chrysotile.  Atmos. Environ., 7: 481-483 (1973).
Air samples collected from nine international cities contained small concentrations of asbestos fibers; most occurred as single fibers, but some were in agglomerates containing many fibers. The pathological significance of these fibers is unknown; but contamination of city air with asbestos fibers may explain the presence of asbestos bodies in lungs of city residents not occupationally exposed to asbestos. Morgenroth, K., Cellular reaction in the human lung caused by inhalation of asbestos dust over long periods., Beitr. Path. Bd., 148: 199-210 (1973) The cellular reaction in human lungs caused by the inhalation of asbestos dust was examined in biopsy specimens with an electron microscope. Smaller asbestos particles are phagocytized by alveolar macrophages and deposited in cytoplasmic phagosomes. Larger particles, coated or uncoated, locate in the alveoli and in the connective tissue septa. fyers, J.L., Osha standards and the safe use of asbestos., Technical Papers, pp. 28-35 (1973).
Rost of the news media treatment of the asbestos problem has been aistorted witb failure to place asbestos toxicity into a logical perspective.
Asbestos can cause disabling lung disease as do many other foreiqn bodies. Asbestos inhalation is statistically related to an excess occurrence of asbestosis and bronchogenic carcinoma in cases of long term exposure. There is some evidence to suggest a co-carcinogenic relationship between asbestos and cigarette smoking. Although the general public is in no danger from asbestos fibers in the urban air there is evidence that crocidolite and amosite industrial air emissions should be more strictly controlled than chrysotile; the evidence linking development of mesotheliomas from exposure to these two asbestos forms is statistically strong. Approximately 200,000 employees are under health risk in the asbestos industries (insulation, shipbuilding, construction, etc.). A new standard for exposure to asbestos dust was published in the Federal Peqister v. 37(110) wed. June 7, 1972. The basic exposure standard is an 8 hr (TWA) limit of 9; fibers longer than 5 micrometers/cc of air; this fiber limit will be reduced to 2 on July 1, 1q76. A peak concentration of 10 fibers/cc is not to be exceeded. All places of employment where asbestos fibers are released were to be monitored within 6 months. Caution labels are required on products containing asbestos except as modified by bonding aqents or other agents to prevent dusting. There is little information available on the release of respirable asbestos from brake linings, however, a PHS study showed that less than 1W remains as free fiber after wearing. Most of the 40-9;0% used in linings is thermally converted to a non-toxic material, fosterite. Asbestos also is used in reinforcinq, heat stabilization and flov control in the plastics industry.  58-60 (1973) Sclerotic f ibrosis, bronchial cancer, and asbestosis are occupational diseases resulting from asbestos exposure. Detection of asbestosis is difficult because the condition produces no macroscopic lung effects, regardless of the severity of the case.
Since effects of asbestos exposure may manifest 20 to 30 years after occupational exposure, the cause of bronchial cancer usually is not associated vith asbestos. Detecting, with accuracy, small quantities of asbestos particles in lung tissue of occupationally exposed workers continues to he the major problem in diagnosing mild asbestosis an1 cancer risk.  (5806): 352-353 (1973) Asbestos fibers injected into the stomachs of rats penetrated the gut and accumulated in the blood, spleen, heart, lung, and brain in significant concentrations. Asbestos elimination from the blood vas rapid; other tissues showed longer retention.
The omentum which surrounds the small intestine accumulated the most asbestos. duration of exposure was 27 years; the latent pertod between first exposure and the development of laryngeal cancer ranged from I to 58 years. maximum incidence in asbestos workers occurred in the 51 to 60 age group whereas the maxtimn incidence of unexposed individuals resided in the f1 to 70 age group. The patients' smoking habits were similar, irrespective of their exposure to asbestos. ASBESTOS; OCCUPATIONAL BEPOSURE; CANCER; CARCINO"A; RUM AN <76> Stell, P.M. McGill, T., Asbestos and cancer of head and neck., Lancet, 1(7804): 678 (1973) Of 100 male patients with carcinoma of the head and neck, 22 had been exposed occupationally to asbestos. Tn a control group of 100 patients having non-malignant diseases, only 2 had been occupationally exposed. The mean latent period between initial exposure and development of carcinoma was 31 years, with an average exposure duration of 24  Taskinen, E.; Ahlaan, K.; Vitkert, H., A current hypothesis of the lymphatic transport of inspired dust to the parietal pleura., Chest, 64(2): 193-196 (19731 The autopsy of a 7'-vear-old male molder --employed for 41 years in iron foundries --showed heavy mixed-dust pneumoconiosis. Black linear streaks in the parietal pleura were microscopically interpreted as periartertal lymphangitis and fibrosis caused by the dust. It is hypothesized that the dust particles were transported from the lungs wia the lymphatic wessels partly in retrogression. Small asbestos particles causing pleural plaques may he transported by the same mechanism. Trtratracheal injection of amosite dust (S0 mg) in guinea pigs consistently lowered the albumin/globulin ratio by decreasing albumin and increasing globulin levels in serum; after 120 days, the ratio was reduced to 1/2 of the normal level.
Fesale guinea pigs were inoculated intratracheally with a sterilized dust suspension containing 7S mg of amosite (less than 30u fiber length). The lungs exhibited gradual development of reticulin fibrosis at 150 days after treatment. More diffuse fibrosis was evident at 300 days, and conststed of thick reticular fibers with stray collagen fibers. The hydroxyproline and glycosamine content of the lungs slowly increased from 60 to 300 days after treatment, indicating a gradual formation of collagen protein from reticulin. The non-collagen protein in treated' animals was 60t hiqher at 90 days than for control animals. AMOSTTE; FIBROSIS; LUNG; GUINEA PIG; ASBESTOS <81> Viswanathan, P.N.; Rahman, Q.; Beg, n.U.; Zaidi, S.H., Pulmonary lysosomal enzymes in experimental asbestosis in guinea pigs., Enwiron. Physiol. Biochem., 3: 120-126 (1973) Amosite fibers (below 3% in length) vere suspended in phystological saline at a concentration of 50 mg/ml. Guinea pigs (300-325q) were given 1.5 ml of the sterilized suspension intratracheally. The controls received only sterile saline in the same manner. Enzyme assays were performed on homogenized lung tissue. The assays performed included acid phosphatase, ribonuclease, cathepsin, and catalase. Intratracheal injection of amosite which initiated phagocytosts in the lung of guinea pigs also initiated a gradual release of lysosomal eazymes from their latent state. As asbestotic lesions progressed, hydrolytic enzymes became capable of degrading DNA and RNA and proteins. Acid phosphatase possibly deprived cells of wital phosphate esters, thereby hampering metabolism. The membraneous structures of pulmonary cells excluding lysosomes also were affected by asbestosis. This suggests that the mechanism of action of asbestos involwes disruption of cell membranes with subsequent release of enzymes or increased permeability to substrates. AMOSITE; GUTIEA PIG; LUNG; ASPESTOSIS; STLICOSIS <82) wagner, J.C.; Berry, G.; Timbrell, V., Mesothelionata in rats after inoculation with asbestos and other materials., Brit. J. Cancer, 28: 173-185 (1973 (5): 165-171 (1973).
A survey including 232 cases of diffuse pleural mesothelions in South Africa shoved that in 32 cases there was no evidence of asbestos exposure; that nearly all of the miners in the group were exposed to Cape Blue Asbestos (Crocidolite)-21 of these miners had a history of both asbestos and man9anese mining; and that in 76  Rossiter, C.E., Radiographic and physiologic patterns among workers engaged in manufacture of asbestos cement products: a preliminary report., J. occup. Med., 15 (3): 218-252 (1973).
A comparative study of the health effects from asbestos and silica dust exposure in 908 asbestos cement workers was evaluated using an occupational questionnaire, chest x-ray, and pulmonary function tests. Five exposure indices were calculated according to total dust exposure and duration of employment for each worker. Chest x-rays revealed small rounded and also irregular or linear opacities: the frequency of both types increased as the cumulative dust exposure increased. Diffuse radiological chanqes correlated better with total dust exposure than with total duration of employment in the industry. Individuals with a moderately advanced profusion of irregular opacities tended to have lower lung volumn and reduced pulmonary diffusing capacity than those with rounded opacties. Hyperinflation was associated with rounded nodular changes. The results suggested that small rounded opacities primarily were due to silica exposure, and irregular opacities to asbestos exposure. ASBESTOS: CROCIDOLITE; X-RAY; OCCUPATIONAL EXPOSURE; RESPIRATORY DISEASE; VENTILATORY DEFECTS; HUMAN <86> Witt, L., "Each glass is another moment of truth"., Today's Realth, 51(10): 44-49 (Oct. 1973).
The induction of extensive pulmonary fibrosis in monkeys exposed to asbestos was related to a low grade infection produced by CANDIDA ALBICANS, a facultative pathogen commonly found in the hunn respiratory tract. Combined intratracheal inoculation with amosite and C. ALBICANS produced extensive collagenous fibrosis at 330 days. Amosite dust alone induced reticular fibrosis and moderate interstitial fibrosis. The C. ALBICANS infection alone initially caused acute inflammatory reaction which declined to normal within 330 days. APOSIE; FIBPOSTS; MONKEY <88> Zeed ilk, H. R., Investigation of asbestos bodies and asbestos fibers found in the lungs of a mesothelioma patient by electron microscopy., Nikrochim. Acts, 6: 977-9884 (1973 Anonymous, Mainly qood news about asbestos., Food Cosset. Toxicol., 10: 474-977 (1972 Definitions and procedural and interpretative regulations., wed. Regist., 37(14411: 114872-14873 (1972) . rhe FDA regulation banning all asbestos-containing qarments was ammended so that garments necessary for personal protection aqainst thermal injuries and constructed so that asbestos fibers will not become airborne would be excluded. The legality of the order is discussed. ASBESTOS; CANCER; FIPRPOSTS; MESOTHELIOMA; STANDARDS <93> Anonymous, Pan of asbestos fibers for clothing proposed after FDA study of hazards., FDA Papers, 6 1) -: 32 (1Q72) . k regulation oroposed by the PDA bans the use of asbestos fibers in cloth used for general purpose garments; its use would be permitted for garments intended for firefightinq purposes. x simulated wearer test of a women's coat (manufactured from fabric containing 8% asbestos) was conducted by the National Institute for Occupational Saftey and Health; the results were evaluated by a committee of experts on asbestos hazards who concluded that no real danger existed but that future use of asbestos in garments for the general public was undesirable.
The smoking habits and lung cancer mortality rates of 1300 male and 480 female asbestos factory workers were examined over a ten year period. Wactory vorkers who smoked and were heavily exposed to asbestos had a significantly higher incidence of death from lunq cancer than expected. Increased mortality did not result in workers with low to moderate exposure. ASBESTOS; LUNG; CANCER; TUMOR; CARCITOMA; OCCUPATIONAL EXPOSURE; CANCER MORTALTTY <97> Boiteau, R.L.; Robin, M.; Gelot, S., Polvcvclic hydrocarbons in various materials containing asbestos., Arch. Mal. Prof. ned. Trav. Secuir. Sociale, 33 (6): 271-286 (1972).
Several hypotheses are presented to explain the carcinogenic potentialities of asbestos. Analyses of 12 chrysotile-containing materials revealed that a third of the samples contained three carcinogenic compoundsbenzo(a}pyrene, benzo(alanthracene, and dibenzo(a,h)anthrance. Since unprocessed chrysotile contains no polycyclic hydrocarbons, these contaminants probably attach during transport and industrial treatment. Asbestos fibers naturally contain nickel and chromium, two trace metals which lnhibit henzopyrene-hydroxylase in the lungs and thus retard the metabolic degradation of the carci nogeni hydrocarbons. ANALYSIS; ASRESTOS; CHWTSOTILE; CO-CARCINOrEN; TRAC? MRTALS (98) Bothan, S.K.; Holt, P.F., The effects of inhaled crocidolites from Transvaal and Worth-west Cape mines on the lungs of rats and guinea pigs., Brit. J. Exp. Pathol., 93(6): 612-620 (1972) . Guinea pigs and rats were exposed for 1100 hours to an atmosphere containing a high concentration of Northwest Cape crocidolite fibers. Another qroup of guinea pigs was equally exposed to Transvaal crocidolite. Alveolar space was reduced in all the lungs due to cellular prolitferatton of the septa. In guinea pigs, giant cells were common with development of asbestos bodies, whereas in rats giant cells were rare and only a few atyoical asbestos bodies were seen. Worthwest Cape crocidolite produced greater disruption of the respiratory surfaces.  A survey of patients having pleural abnormalities and attending chest clinics in the United Kingdom showed no evidence that exposure to asbestos was more common in the group with abnormalities than in a matched control. A greater proportion of those with pleural abnormalities had a history of previous pleural inflammation and injury.
Electron miscroscopic examination of a lung biopsy specimen from a case of desquamative interstitial pneumonia (DIP) revealed that the alveolar cells lining the alveolar walls are granular pneumocytes; free cells in the lumen, however, were alveolar sacrophages. Tn this instance asbestos bodies were present in the lung, suggesting that DIP is not a specific disease entity. MACROPRAGE; ASBESTOS BODIES; LUNG; DYSPNEA; FINIGE CLUBBING; WUHAN <103> Flder, J.L., A study of 16 cases of pleurisy with effusions in ex-miners from wittenoom dorge., Aust. W.Z. J. Med., 2(1-5): 328-329 (1972).
Tn a follow-up study of 10 cases of bilateral and six cases of unilateral pleural effusion in ex-miners from a crocidolite asbestos mine, an association was established between asbestosis, lung cancer, pleural plaques mesotheliona and pleural effusion; there was, however, insufficient evidence to prove that benign asbestos pleurisy is an entity. In some cases, pleurisy preceded the disease; however, in three of the 6 cases of asbestosis, radiological evidence of asbestosis was present at the time of the first effusion. Thirteen of the 16 cases of pleurisy were attributed to asbestos exposure. Clinical picture of dust-induced pulmonary disease following exposure to some types of the silicate dust., Gig. Tr. Prof. Zabol., 16 (10): 8-11 (1972).
The type of occupational exposure determines the kind of dust-induced pulmonary disease as indicated by observations of 143 patients and workers exposed to several silicate dusts including asbestos, clay, and chamotte. Pneumoconiosis is produced by clav and chamotte dusts and is characterized by a relattvely benign course, whereas asbestosis manifests as a progressive pulmonary insufficiency. The functional state of the respiratory system should be considered when determining the work load of patients. Rabbits were exposed to either chrysotile, amosite, or crocidolite asbestos dust at a dose of SO mq/Cu m for 4 days/week/54 hours/day for 1 year. One half also received the imunosuppressant drug "Tmuran" brand Azath ioprine while the other half was untreated. Pulmonary function tests were given before, during and after exposure and no signiftcant differences were found in the two groups. Pulmonary macrophages evidently play no significant role in protection against development of asbestosis. Wo observable differences were found between the two groups upon pathological examinatton. (1 07o Gibbs, G.W.; LaChance, M., Dust exposure in the chrysotile asbestos mines and mills of Quebec., Arch. Environ. Health, 24: 189-197 (1972 83-93 (1972). A lung biopsy revealed asbestosts in a 47-year-old woolen mill worker 16 years after he was exposed to Cape Blue asbestos. He had been been exposed for.  Arbeitsmed., 30: 273-282 (1972).
Histochemical studies of microscopic sections of human lungs with asbestotic lestons and asbestos bodies suggest that the body coating consists of two basic layersthe first consists cf proteins, hematoidin, and ferric iron deposited over the fibers. The second stage forms when hyaluronic acid is laid around the first layer and other ferric iron particles impregnate the hyaluronic acid molecules. Thirty-one cases of mesothelioma were recorded in 42,597 death certificates of children who died of cancer in the U.S. from 1960 -1968. Hospital records confirmed 13 cases. Illness was characterized by acute pleural effuston and tumor encasement of the lung, usually with less than 6 months survival. Case histories had no information' concerning environmental exposure to asbestos. ASBESTOS; ENVIRONMENTAL CONTAMINATION; RESOTHELIORA; LUNG; TUMOR; HUMAN; NOW-OCCUPATTONAL EXPOSURr <112> Harries, P.G.; Mackenzie, F.A.F.; Sheers, G.; Kemp, J.H.; Oliver, T.P. Wright, D.S., Radiological survey of men exposed to asbestos in naval dockyards., Brit. J. Ind. ed., 29(31): 2'4-279 (1972).
Radiologtcal surveys of a 10W sample population of men exposed to asbestos in naval dockyards showed a prevalence of asbestos related abnormalities. Pleural abnormalities were found 10 times more frequently than parenchymal disease. At Devonport Dockyard 37 men have developed mesotheliona since 1965. There was no evidence that smokinq increased the incidence of asbestos abnormalities.  Sci., 200: 552-569 (1972).
A review of international experiences with the UICC/Cincinnati Classification indicates that its basic goals have been accomplished. Althouqh some of its features have presented difficulties, its 12 point scoring system and the concept of involvement have simplified the decision-making-process. Several periodical changes have been made to improve the system and presently recommendations for combining the hTO and U/C Classification of Radiographs are being considered. The following aspects of the system are discussed: (1) profusion of small opacitties, (2) extent of small opacities, (3) large opacities, and (4) pleural thickeninq. ASBESTOS; ASBESTOSIS; PNEUMOCONTOSIS; SILICOSIS; STANDARDS (115> Wannerstein, W.; Churg, J., Pathology of carcinoma of the lung associated with asbestos exposure., Cancer, 30 (1): 14-21 (1972 Kogan, F.M.; Gusel'nikova, N.A.; Gulevskaya, M.R., The cancer mortality rate among asbestos industry workers in the Urals., Gig. Sanit., (7): 29-32 (1972) Results from a 20 year study show that the mortality rate due to cancer is higher among asbestos workers than the general population. A higher inCdlLdce of cancer was also noted in the elderly. Cancer of the lungs and stomach was less prevalent in female asbestos workers than in male workers, but significantly higher than in women with no occupational exposure to asbestos. Questionnarte results from 1,015 males employed in chrysotile asbestos mines and mills indicate that prevalence of persistent cough and phlegm (bronchitis) was primarily determined by age and smoking habits. Since smoking was the main determinant of bronchitic symptoms, the effect of dust exposure was evident only in non-smokers. Perris, B.G., Low exposure to asbestos., Arch. Environ. Wealth, 25: 253-264 (1972).
A follow-up survey on New England shipyard pipe coverers focused on asbestos-induced physiologic abnorealities. Compared to controls, the pipe coverers exhibtted significantly reduced vital capacity (PVC) as well as reduced single breath (DLSB) and exercise steady state diffusing capacity (DLSS-R) . Workers with clinical masbestosism had severely reduced diffusinq capacity (DL) and fraction carbon monoxide resoved. Three tears later, DL in exposed workers had deteriorated more rapidly than NVC; some with initially isolated reduction of rL had developed other signs of disease. ASBESTOS; ASBESTOSIS; LUNG; FINGER CLUBBING; IMPHYSEMA; X-RAY; SHIPYAPDS; PIPE COVERERS; OCCUPATIONAL EXPOSURF; VENTILATORY DEFECTS <120> Navratil, M.; Trippe, F., Prevalence of pleural calcification in persons exposed to asbestos dust, and in the general population in the same district., Environ. Res., 2: 210-216 (1972) Prevalence of pleural calcification in humans was closely related to asbestos dust exposure directly or indirectly by occupational, family, or neighborhood contact. Asbestos appears to be. primarily responsible for pleural findings, although other unknown factors may be the cause of some pleural disease. ASBESTOS; OCCUPATIONAL EXPOQSRE; NOW-OCCUPATIONAL EXPOSURE; PLEURAL CALCIFICATION <121> Newhouse, M.L.; Berry, G.; Wagner, J.C.; Turok, M.E., A study of the mortality of female asbestos workers., Brit. J. Ind. Med., 29: 131-1-11 (1972). Increased mortality was found in a group of more than 900 women employed at an asbestos textile and insulation manufacturing plant. Those exposed to low and moderate levels had increased cancer deaths whereas severe exposure for less than two years caused cancer of the lung and pleura; in those severely exposed for more than two years, excess deaths were from cancer of the lunq and pleura, other cancers, and from respiratory diseases. The mortality was compared with national levels. The proportion of smokers was higher than the national rate, which could account for some of the excess mortality. Age at first exposure was not a contributing factor. Asbestos filters are widely used by the pharmaceutical industry. Tn the U.S., measurable amounts of asbestos have been found in parenteral solutions used for therapy. Whether asbestos causes human disease by routes of adminstration other than inhalation is still unknown. However, Ingestion of asbestos is suspected of being hazardous due to increased incidences of gastrointestinal cancer among asbestos workers. Nurminen, M., A study of the mortality of workers in an anthophyllite asbestos factory in Finland., Work,Environ.,Health,).
Results of a mortality study on workers in an asbestos factory in Finland indicated the following hazards of exposure to anthophyllite asbestos dust: (1) Overall mortality from cancer of the lung, bronchus, and trachea, from respiratory tuberculosis, and from other respiratory diseases was excessive. (2) Every fifth deceased member of the survey had asbestosts recorded on the death certificate as an underlying or contributing cause of death.
(3) In certain age groups with a minimum exposure of more than three months, mortality from lung cancer was more than three times the expected number. The survey period was from 1936 to 1966 with mortality analysis up to the end of 19fB. The minimum exposure to asbestos was three months. ANTROPHYLLITE; OCCUPATTONAL EXPOSURE; ASBESTOSIS; CANCER; LUNG; HUMAN; RESPIRATORY DISEASE (1 24> Orfila, J.; Lepinay, A.; Vasseur, M.; Bouffant, L.L.; Martin, J.C.; Taniel-Moussard, R., Effect of quartz, coal, titanium oxide, and asbestos dusts on experimental CELANYDIA PSITTACI infection in mice., Coapt. Rend., Ser. D (Parts), 274 (9): 1434--11137 (1972) When injected into mice, the infectious agent CULAMYDIA PSITTACT, induces ornithosis; this was aggravated by pretreatment of the animals with i.p.
In Mereburq, East Germany, pleural plaques were found in 458 workers by x-ray analysis in 1970. Although most worked 4n the chemical industry, the majority of patients had been exposed to asbestos prior to 1945; -15% experienced indirect exposure. The mean latent period was 20 to 30 years. Electron microscopic examination of asbestos bodies extracted from human lungs exposed to crocidolite, amosite, anthrophyllite, and chrysotile presented no evidence to suggest stepwise form#tion of asbestos bodies. They were nearly always formed on straight fibers longer than 10 um. Asbestos bodies were found to contain a major crystalline component structurally similar to extracts of ferritin (produced from animal and human organs). Tumor incidence in rats was about 40% after intraperitoneal injection of either 100 mg U..C.C. --a standard chrysottle (fiber length is less than 5 um)--or 100 sq of powdered chrysotile (fiber length is less than 3 us). Mowever, the latent period between exposure and tumor development was longer with powdered chrysotile. Addition of 1.25 *g of benzo(a)pyrene did not significantly influence tumor incidence, but without chrysotile, benzo(a)pyrene induced tumors in 10% of the animals. ASBESTOS; CHRySOTTLE; TUMOR; RAT; CO-CARCINOGEN (128> Rajan, K.T.; Wagner, J.C.; Evans, P.R., The response of human pleura in organ culture to asbestos., Nature, 238 (5363): 346-3417 (1972).
Ruman parietal pleurae maintained in organ culture and exposed to blue asbestos showed marked proliferation of mesothelial cells. Some cells had larger nuclei and invaded underlying tissue. The amount of collagen was increased in the underlying tissue. Since tissues in organ culture respond to asbestos fibers in a relatively short period, the system should be useful for investigating the effects of other fibers, chemicals and carcinogens. Robinson, J., Pleural plaques and splenic capsular sclerosis in adult sale autopsies., Arch. Pathol., 93: 118-122 (1972).
In 2,516 autopsies on chiefly adult males in a Florida Veterans Administration Rospital, a similar incidence of pleural plaques was observed in both whites and negroes, but splenic capsular sclerosis occurred primarily in whites and at a later age. Pledral plagues were not associated with asbestos bodies or *esothelial neoplasia, indicating that they should not be considered as evidence of asbes tosis. ASBESTOS BODIES; ASBESTOSIS; PLEURAL PLAQUES; RUMAN <13 > Rossiter, C.E., Evidence of dose-response relation in pneumoconiosis (1)., Trans. Soc. Occup. ted. , 22: 83-87 (1972).
A technique for deteraininq the severity of simple pneumoconiosis has been developed using a coAtinuous scale for scoring radiographs based on the profusion of small.round lung opacities. Usinq this technique, a direct relation between radiographic change and dust content of the lungs was evident in coal miners. Since asbestos is a biologically active dust, radiographic changes reflect pathological changes rather than the amount of asbestos in the lungs. The differences between the biological activities of the dusts inhaled by coalsiners and asbestos workers are seen in relatively poor relations to mortality, pathology and lung function in the former and better relation for dockyard and chrysotile asbestos workers. ASBESTOS; ASBESTOS NINTYG; CPRYSOTILE; RUMAN; DIAGNOSIS; FIBROSIS; PNlEUMOCOWIOSTS; I-RAT <1 32> Ruttner, J.R.; Spycher, N.A.; Sticher, W., Diffuse 'asbestosis-ilce' interstitial fibrosis of the lung., Pathol. Microbiol., 38(4): 250-257 (1972).
Comprehensive chmical, mineralogical, and electron microscopical analyses of lung dust from a case of diffuse pulmonary fibrosis which morpholoqically resembled asbestasis revealed platy silicates but no asbestos fibers. Mica, kaolinite, and feldspar are, as in asbestos, less transportable in the interstitial lymph spaces than are small quartz crystals. Therefore they do not accumulate to the same extent in peribronchial and perivascular sites; thus a diffuse rather than a nodular type of pneumoconiotic fibrosis results. The incidence of mesotheliomas in rats qiven 14 mg chrvsotile was 17; in conjunction with Pu 239 (720 nCi), the-incidence increased to 43g. Asbestos appears to act in a synergistically with Pu 239, and the pathogenesis of the mesotheliomas is similar to that seen with Pu 239 alone. Survival rate vas significantly reduced in rats given both asbestos and Pu 239. ASBESTOS; CHRYSOTILE; MESOTHELIOMA; SARCOMA; RAT (134> Schneider, T., Ashestos dust levels during work with cloths made from liquid dispersed chrysotile., Ann. Occup. Hyq., 1S: 425-426 (1972).
Chrysotile asbestos fabrics manufactured by a liquid dispersion method produce considerably less dust during handling than does conventional asbestos cloth. Usinq these cloths, much less dust was qenerated while manufacturing mattresses and pipe insulation.  759-772 (1972) The surface of asbestos and other mineral fibers showed marked interaction with cell membranes in vitro. chrysotile was lytic for human, sheep, and horse red blood cells (PBC) with a 50% hemolytic concentration (HCSO) of 0.2 mg/ml or less. The lytic activity was inhibited by ethylenediaminetetracetic acid (!DTA) or by anionic polymers. Amphibole fibers were lytic when RBC exposure took place in a shallow layer with gentle agitation. Human RBC's were more sensitive than sheep RBC's; the RCSO was 10 mg/ll for amosite, During the last .two decades, increasing interest in envtronmental problems has grownespecially with respect to asbestos-related cancer. Razards associated with asbestos apparently were limited at first to occunational exposures and now affect a large segment of society. The following aspects of asbestos are discussed: properties and uses of asbestos; types of asbestos; and related health hazards. However, specific attention is focused on the problem of neoplasta and asbestos exposure and international collaboration in an effort to solve tbe problem. Proceedings of an International Symposium, (London, 1970). W.. Walton (Editor). Unwin 5rothers Limited, Greshan Press, Surrey, Enqland., pp. 437-445 (1971).
Evidence suggests that silica particles do not damage plasmaa enmbranes of macrophages but are ingested into secondary lysosomes. Protection of lysosomal menbranes against silica is achieved by polymers such as polyvinyl pyrtdinio-acetic actd. Asbestos, eppecially chrysotile, when added to macrophages or mesothelial cells in the absence of serum, lyses the cells by interaction with the plasma membrane. in the presence of serum the asbestos particles are much less damaging than silica, whether or not they are ingested into the lysosomal system. ASBESTOS; CRRYSOTILP; CELL CULTURE; RACROPRAGE; HEHOLYSIS; CYTOTOXICITY Environmental Health Perspectives <139> Allison, A.C., Lysosomes and the toxicity of particulate pollutants., Arch. Intern. Med., 128(1): 131-139 (1971) In vitro laboratory studies indicate that some inhaled particles, especially silica and asbestos, react with macrophage cells differently than do inert particles such as carbon. Silica 'and asbestos act as hydrogen bonding agents that alter the secondary lysosonal membrane; this catises loss of the lysosonal enzymes, destruction of the macrophaqe, and the release of unknown factors that induce fibrotic tissue response. Since the physiological activity of talc apparently is related to the asbestos fiber content, the threshold limit values (TLV) recommended for work areas differs for non-fibrous and fibrous types. A value of 20 mppcf is recommended for non-fibrous talc; 5 fibers per milliliter of air for those exceeling q microns in length is the limit for fibrous talc due to the similarity in the fibrotic reaction produced by talc and asbestos. ASBESTOS; FTBPOSIS; HUMAN; STANDARDS; OCCUPATIONAL ETPOSU RE <1142> Anonymous, Asbestos: questions still unanswered, Food Cosmet. Toxicol., 9: 281-284 (1971). A brief review is given of the sometimes contradictory evidence relating asbestos exposure with asbestosis, lung tumors, and mesotheliomas of the pleura or veritoneum. Both experimental and epidesiological studies are cited. There are obvious differences in the effect of various types of asbestos. Badr, F..;El-Sewefy, A.Z., The association between asbestosis and A B 0 blood groups., Ann. Occup. Hyg., 14: 35-40 (1971).

ASBESTOS
Clinical and radiological examinations of workers intermittently exposed to asbestos, silica and cement dusts In a cement pipe factory in Egypt have shown that the incidence of asbestosis usually is directly related to the duration of exposure.
However, approximately 20% of the workers never develop clinical or radiological signs of asbestosis regardless of the duration of erpsure. The resistance implied may.be attributed to inherent genetic mechanisms or to developing defense mechanisms induced by specific extrinsic factors.
Increase of globulin fractions IgG, IgM, and IqA in diseased workers ndicates an immune response. Tn workers showing c inical and radioloqical signs of asbestosis there t:s an increased frequency of the blood group 0 compared with workers from control groups. The genetical aspects of asbestosis susceptibility warrants further investigation. Tn rats injected intraperitoneally with chrysotile and crocidolite fibers, the severity of asbestosis varied directly with the fiber length used.
Granulomas produced by the i.p. inlection of UICC amosite, crocidolite, and anthophyllite in rats contained a higher percentage of long fibers than did the original dust; mostly short fibers were deposited in the lymph nodes, indicating that the short fibers are readily transported by the lymphatic system. The permeability of cultured L-cells was increased to a qreater extent by lono chrysotile and glass fibers than by short fibers, due to incomplete or prolonged phagocytosis of the fibers by the cells. Altered permeability of cell membranes by cytotoxic substances can be estimated several ways by cell culture techniques: eosiny stains damaged cells, enzymes such as lactic dehydrogenase leak from cells into the supernatant fluid, and metabolic activity such as lactate synthesis is reduced. The additton of chrysotile to monolayer cultures of peritoneal and alveolar macrophages increased eosin-y uptake and lactic dehydroqenase activity after 20 hrs; at the same time, however, there was an increase in lactic synthesis indicating that the permeability increase occurs during phagocytosis of fibers and does not result from cell damage. chrysotile treated with acid was cytotoxic, causing a larger increase in membrane permeability with a reduction in lactate synthesis. Effects of chrysotile coated with poly(2-vinyl-pyridine 1-oxidel on permeability did not differ significantly from untreated chrysotile. ASBESTOS; CWRYSOTILE; GUINEA PIG; MACROPRAGE; PHAGOCYTOSIS; CELL CULTURE; CYTOTOXICITY <146> Beritic, T.; Dimov, D.; Bunarevic, A.; Sondic, M.; Sirec, A., Asbestos and ferruqinous bodies., krh. Rig. Rada, 22 (4): 317-322 (1971).
Perruginous bodies were found in 1i8 of the lung smears taken from 450 necropsies. An attempt to differentiate between ferruginous bodies of asbestotic origin and those of non-asbestotic origin by their iron-staining characteristics failed to produce discernable differences. Prussian blue stains were used. No occupational histories were established. ASBESTOS: ASBESTOS BODIES; PEERUGINOUS BODIES; HUMAN <1147> Bey, E.; Harington, J.S., Cytotoxic effects of some mineral dusts on Syrian hamster peritoneal macrophages., J. Rxp. ned., 133(5): 1149-1169 (19711 . Hamster peritoneal macrophage cell cultures were inoculated with various mineral dusts to study cytotoxic effects. Cells phagocytosing amosite and crocidolite showed no specific damaging effect; however, some loss of cells occured in the cultures within 3 days due to over-inqestion of particles.
In contrast, chrysotile was highly cytotoxic, causing vacuolization of the cytoplasm, collapse of ruffled membranes, and the appearance of large numbers of pyknotic cells. A comparison of two chrysotile preparations which differed in surface area showed that weiqht rather than surface area of the fiber determines toxicity. Pretreatment of chrysotile with tryptose phosphate broth accelerated but did not increase the intensity of the cytotoxic effect. The results with silica dusts are dtscussed also. ASBESTOS; CELY. CULTURE; CYTOTOxICITY; HAMSTER; MACR OP HA GE <1148> Bothas, S.K.; Holt, P.F., Asbestos-body formation in the lungs of rats and guinea-pigs after inhalation of anthophyllite., J. Pathol., 107: 2415-242 (19'71. Rats and guinea pigs were exposed to Finnish anthophyllite in a dustinq tunnel. within a month after Inhalation of anthophyllite some asbestos bodies developed in the guinea pig lungs but were rarely foundl In the rats, even after 18 months. In the rat, both the dust and the ferruginous material are removed by macrophaqes that seldom fuse, whereas in the guinea pig, formation of giant cells is  (11971) The origin of alveolar macrophages and their responses to particulate materials are discussed in detail. Two features distinguish the alveolar macrophage response to asbestos from the reaction to silica: giant cell transformation and the formation of asbestos bodies. The latter process may serve to neutralize the toxic action of the asbestos particles. ASBESTOS; ASBESTOS BODIES; MACROPHAGE; GIANT CELL; SILICOSI S <150> Brain, J.D., The effects of increased particles on the number of alveolar macrophages. , Inhaled Particles ITI: Proceedings of an International Symposium, (London, 1970). W.H. Wditon ('ditor).
A lung washing technique was used to estimate the number of free cells (alveolar macrophages) produced in rats and hamsters by the intrapleural iniection of coal dust, carbon, chrysotile, Iron oxide, and barium sulfate particles. The lungs were excised, gas freed, cannulated and vashed 12 times at 4 hrs., 1 day and 3 days following injection. All materials increased the rate of macrophage production; this, in turn, increases the probability that the particles will be phagocytosed and will remain on the alveolar surface rather than pentrating fixed lung tissue. The role of asbestosi; in the rising frequency of pleural and peritoneal mesothelioma and of broncho-pulmonary cancer is discussed in the light of published epidesoloqic and experimental studies. Pulmonary fibrosis is becoming less frequent, probably due to increased protection in the asbestos industry. Since world production has increased eightfold in the past 10 years, air pollution from these fibers may have become a problem for the population at large. The tritiated thymidine technique was used to examine the cytodynamic reactivity of the pleural mesothelium in rats following the intratracheal injection of synthetic or natural chrysotile. Within R days, natural chrysotile had produced a significant increase in the labeling index of mesothelial cells; in addition, the loss of label from this group after the administration of tritiated thysidine at time of treatment occurred more rapidly than in control rats or those treated with synthetic chrysotile. Synthetic chrysotile also failed to produce a comparable increase in the labeling index. These observations indicate that the pleural mesothelius displays a high degree of sensitivity to natural chrysotile.
Asbestos workers were studied regularly for several years by chest X-ray, vital capacity, 1-second vital capacity, and lunq compliance ditagnostic procedures.
A case of rare primary intrapulmonary neurogenic sarcoma with accompanying hypertrophic pulmonary osteoarthropathy and asbestosis is presented and 5 previously documented cases are reviewed. The patient, a non-smoker, had been occupationally exposed to asbestos for 20 years. After surgical removal, the tumor recurred in six months causing death withtn 16 months. Histological features of the tumor are discussed. Cell culture and In Vivo studies of asbestos, polyurethane, polyethylene terephthalate (PEP) and acicular calcium carbonate indicate that a direct relationship exists between the fibrogenic and cytotoxic effects of dust. In cell suspensions of peritoneal or alveolar macrophages asbestos was the most cytotoxic dust, as indicated by the mortality incidence of cells which had phagocytosed dust particles. Asbestos also was the most fibrogenic dust in rats inoculated intratracheally or intraper itonea lly. The cytotoxic-fibrogen ic effects were unrelated to the shape, size, or concentration of the dust particles, or to the phagocytosing potential of the macrophages. RAT; CELL CULTURE; ASBESTOS; PRAGOCYTOSIS; CYTOTOXI CITY (157> Cralley, L.J., Electromotive phenomenon in metal and mineral particulate exposures: relevance to exposure to asbestos and occurrence of cancer., Amer. Ind. Ryg. Assoc. J. , 3232 (10): 653-661 (1971) Data and hypotheses presented relate the biological activity of asbestos to the electromotive interaction between trace metals and minerals associated with the fibers. The trace metals consist mainly of nickel, chromium, manganese, and iron. In lung tissue, the electromotive phenomenon results in the concentration of biologically active metals at localized tissue sites, and increased residence time at these sites. This may explain the exacerbations of diseases, sensitization reactions, carcinogenicity, latency period and other responses of tissue to asbestos. Cralley, L.J., Identification and control of asbestos exposures., Amer. Ind. Ryg. Assoc. J., 32 (2) : 82-85 (197 1) Asbestos can be safely used in industry if proper precautions are takeh. All available analytical procedures must be used to distinguish between, asbestos and other fibers, including neutron activation, electron microprobe, and atomic absorption spectrometry. Recommendations for control are given. In an effort to simplify the comparison of asbestos exposure data from various countries and studies, the Sub-Committee on Asbestosis of the Permanent Commission and International Association on Occupational Health recommended standardization of the procedures used for enumerating and characterizing exposure to respirable asbestos fibers. The Sub-Committee recommended the membrane filter technique for collecttng airborne asbestos fibers and suggested that the samples be taken in the breathing zone of the workers and at fixed sites for evaluation of the effectiveness of safety equipment and procedures. Short but frequent sampling times should be used for determininq maximum exposures while longer sample times should be used for weighted average exposure determinations. Fiber counts should be expressed in number of fibers per cubic centimeter, counting only fibers 5.0 u or more in length with a ratio of length to diameter of at least 3 to 1. The type of asbestos, trace metal content, free silica content, and organic contaminants should also be determined. Other procedures should be tried; however, concurrent data should be obtained by the reccasended procedures. Various beverages and 8 samples of tap water from three major cities in Canada were examined by electron microscopy for asbestos fibers. All samples contained asbestos fibers, either chrysotile or amphibole; filtered water contained less asbestos fibers than unfiltered water. It is noted that the hazard from ingested asbestos has not been resolved. ASBESTOS; INGESTION; CHPYSOTILE; WON-OCCUPATIONAL EXPOSUBRE; AMPRIBOLE; HUMAN; NITTRONIMTNTAL CONTANINATI ON <161> Davis, R.V.: Reeves, A.L., Collagen biosynthesis in rat lungs durinq exposure to asbestos., Amer. nd. Hyg. Assoc. J., 32(9): 599-602 (1971).
The rate of collagen Protein synthesis in animals is directly related to the rate of Froline hydroxylation to form the amino acid hydroxyproline; proline hydroxylase catalizes this reaction. In rats receiving intratracheal or inhaled doses of amosite, crocidolite and chrysotile, the effects of asbestos on proline hydroxylase activity in lunq tissue was measured as a hydroxyline: proline ratio. The ratio vas significantly increased in animals injected intratracheally vith asbestos, indicating that the early stage of fibrotic tissue response is characterized by an increased rate of collagen biosynthesis. The ratio was depressed in animals exposed by ivhalation; the lungs of these animals had developed massive fibrotic lesions with heavily collagenized parenchyma. Intrapleural injection of chrvsotile in guinea pigs indeced rapid development of granulomas; initially, these consisted mainly of giant cells which vere largely replaced by collaqenous fibrous tissue within 18 months. calcification of the fibrous tissue beqan at 12-1s months by the formation of calcium (apatite) crystals and laminated bodies (30-40) containing asbestos cores. nucopolysaccharide was removed from collagen fibers and deposited around remaininq free dust in the fibrous area. The apatite crystals accumulated on surface layers of mucopolysaccharide, guickly fillinq tissue spaces and enclosing the collagen, coated dust, and lamellar bodies in a solid mass of calcif ication. The aim of the Asbestos Regulations is to keep dust out of the air of work places by requiring safe methods of asbestos handling in all industries. Potentially, 140 fatalities per year could occur in the total population of about 50,000 working with asbestos. many industries will face problems in meeting these requlations to protect vorkers. ASBESTOS; STANDARDS; OCCUPATIONAL EXPOSURF; RM)JAN <164> el-Sewefy, A.7.; Rassan, F., Ionmnoelectrophoretic pattern chanqes in asbestosis., Ann. Occup. Myg., 14: 25-28 (1971) Serum samples from 33 male vorkers in an Egyptian asbestos cement pipe factory were examined for imnumoelectrophoretic pattern changes. The workers were exposed to silica, asbestos and cement dust for 10 to 23 years, and all showed clinical and radiological signs of asbestosis. Albumin levels in 63% of the samples were significantly decreased. changes in imsunoglobulins were evidenced by high levels of IgA in 66% of the samples, of TgG in 63%, and of IgM in 54%. The increase in IgG and Tg4 is a characteristic response to chronic inflammatory disease; the IgA increase may reflect an auto-timune response. These changes were not related to the duration of exposure or to the degree of asbestosis. ASBESTOS; OCCUPATIONAL EXPOSURE; ASBESTOSIS; HUMAN; BIOCHETICAL EFFECTS <1 69's El-Sewefy, A.%.; Regazi, S.M., Serum proteins and amino actds in asbestosis., Ann. Occup. Ryg., 14: 29-33 (1971) More free and total amino acids were found in serum from workers showing signs of asbestos is than from healthy controls. The serum protein change suggests that the introduction (inhalation) of asbestos into the hody results in a disruption of protein metabolism. The concentrations of sodium and potassium ions in the serum were normal in the diseased workers. No correlation was found between the amino acid pattern and the extent of Med., 28 (3) : 226-236 (1971) The fate of 16S insulation workers in Belfast with known occupational exposure to asbestos is presented. Between 1940Between -1966 In this group was 98 compared to 37 normally expected; the increase became statisttcally significant after 1Q90. Cancer deaths were nearly eight times more frequent than expected. Twenty-eight of the 45 deaths were from cancer of the larynx, lung or pleura; mortality from cancer of the gastrointestinal tract and from fibrotic lung lesions also was high among insulation workers. Seven cases of mesothelioma were confirmed. The ratio of observed over expected deaths vas 2.6 for all causes, 3.9 for all cancers, and 17.6 for cancers of the lower respiratory tract and pleura.
No correlation was established between aqe at first exposure, duration of exposure, smoking, and the excessive mortality. In a comparative study of shipyard workers, pipe fitters, pipe coverers, and welders, pipe coverers had more marked changes in their lunqs. Pulmonary diffusing capcity was slightly lower, and calcifications and rales in two or more sites were significantly more common among pipe coverers. These findings reemphasize the need for continued control of exposure to asbestos and careful medtcal surveillance of workers. In England 4,223 sets of x-ray films f.rom workers in a shipbuildinq industry were examined and classified according to occupation and the incidence of pleural plaques noted. Calcified or noncalcified plaques were observed in 5*5V of the workmen over the age of 24; the incidence was 33W in joiners, 17.5% in laggers, 21% in caulkers, burners, and drillers, 13.8W in sheet metal workers, and 1.2 -11.5% in other occupations. The results were attributed to varying asbestos exposure. When administered intraperitoneally to wistar rats, amosite, anthophylitte and crocidolite asbestos fibers were distributed in adominal qranulonas and related lymph nodes; in granulomas short fibers were mostly intracellular whereas the longer ones were seldom incorporated. Short fibers were found in lymph nodes without evidence of fibrosis. It was concluded that the transport of asbestos from the site of administration depends upon the fiber length: it begins with fibers less than 270um and increases with decreasing fiber length. AMPRIPOLr; ANTHOPHYLLITE; AMOSITP; ASRESTOS; CROCIDOLITE; FIBROSIS; GRANULOMA; RAT; TISSUP DISTR IBUTION <173> Gee, B.; Bouhuys, A., Action on asbestos., New Engl. J. Ned., 285(23): 1317-1318 (1971). The widespread contamination of air, water and beverages by asbestos, and the presence of asbestos in the lungs of people havinq no industrial exposure is quite disturbing in view of the serious pulmonary diseases related to occupational asbestos exposure. Since asbestos is relatively resistant to destruction and asbestos diseases have a long latency period, there is an urgent need for sweepinq dectsions on the control of asbestos emissions. The following recommendations are made: (1) lowering of thresbold limit values for occupational exposure, Epideniological studies relate adverse health patterns to asbestos dust exposure. Both the quantity and quality of the dust varies from mine to mine, mill to mill, and within any one plant.
Differences in asbestos fiber components and sources also influence disease patterns. Some of the qualitative aspects of asbestos chemistry include organic constituents, trace metals, processing and naturally occurring contaminants, radioactivity, and chemical and physical characteristics. The four main types of asbestos are not equally implicated as carcinogenic agents in humans. The type and source of the asbestos, fiber characteristics, deposition site, cellular reactions, and total dose all may play a part. The Lung tissue from people not occupationally exposed to asbestos dust was found to contain ferruginous bodies with unusual morphology. Some of these cores are transparent and some are opaque whereas others have nonfibrous cores. Those with black, fibrous cores are believed to originate from inhaled smoke particles. Occurrence of mesotheliomas in rats inoculated intrapleurally with two forms of asbestos was slightly greater for Cape crocidolite than for Transvaal amosite. Amosite apparently can produce tumors in the pleural cavity, but less readily than crocidolite and after a longer interval. Chrysotile asbestos hemolyxed sheep erythrocytes (in vitro) vithin 10 min over a pH range of 4-11. Other asbestos forms caused varying degrees of hemolysis which related to the magnesium: silicon ratio. Longer erythrocyte exposure time to asbestos resulted in greater hemolysis. Ethylenediaminetetraacetic acid (EDTA) prevented hemolysis by asbestos and other materials containing magnesium. Sialic acid vas a more effective preventive agent. Poly-2-vinylpyridine -1-oxide had little effect on hebolysis by chrysotile. Magnesium appeared to be the principal agent of hemolysis by asbestos.
Dust measurements indicate that gravimetric methods for monitoring respirable asbestos dust concentration in naval dockyard insulating operations are not adequate. It is recommended that a-membrane filter technique be used. In the removal of pipe lagging there appears to be dust mass and fiber concentration at high dust levels, but not at low levels.
The iron, chromium, cobalt, nickel, and scandium content of five International Union against Cancer (UICC) standard reference samples of asbestos were determined by neutroh activation analysis.
Individual samples of Canadian chrysotiles and South African crocidolites were also analyzed. As determined by high resolution gamma-ray spectrometry, milling caused no significant change in elemental composition of the UICC standards. ASBESTOS; CHEYSOTILE; CROCIDOtITE; TRACE RETALS; ANALYSIS <181> Hounam, R.F., The konimiser--a dispenser for the continuous generation of dust clouds from milligram quantities of asbestos., Ann. Occup. Hyq., 14: 329-339 (1971) Animal inhalation experiments using asbestos demand uniform particle release and distribution. The design, construction, and performance of a dust dispenser suitable for dispersing small quantities of "respirable" radioactive asbestos dust for animal inhalation experiments is dtscussed. Thirty-three asbestos insulation workers were examined to assess the incidence of asbestos-related pulmonary diseases. Results from x-rays and lung function tests revealed no cases of asbestosis, pleural plaques or malignancy. Eiqht men had chronic bronchitis and three others were asthmatic; asbestos bodies were observed in sputum smears from five men. Of these 33 men, 29 had been regular cigarette smokers; however, 19 had stopped smoking, predominantly within the last five years. Despite the negative findings, it is recommended that every person appreciably exposed to asbestos have an annual examination. Med., 284 (14): 778-786 (1971).
A 64 year old man was hospitalized with progressive dyspnea and chronic lung dtsease; he was a heavy smoker, and had been occupationally exposed to asbestos dust for 45 years. Clinical examination showed pleural effusion, mild finger clubbing, and severely depressed pulmonary function. The patient's condition deteriorated rapidly, followed by sudden death. Autopsy revealed pulmonary asbestosis with pleural mesothelioma and asbestos bodies In the lung tissue. An attempt to find early symptoms of lung damage due to asbestos exposure involved a detailed study of pulmonary function in 24 mine workers with normal chest x-rays and exposure ranging from 6 months to 24 years. Workets with the greatest exposure time showed chanqes consistent with restrictive lung disease, includinq increase in static recoil, reduced vital capacity and larger maximal mid-expiratory flow; decreased peak flow in these men Indicated increased upstream resistance. As in animal studies, the results sugqest a peribronchiolar rather than alveolar obstructive restriction. Chest x-rays, questionnaires, and clinical and pulmonary function tests were used to assess the effects of asbestos in 251 insulation workers in Belfast. The proportion of men with abnormal chest x-rays increased with age and with the number of years in the industry. Two-thirds of the men with lung field abnormalities (abnormal reticulation, linear shadows or fine nodulation) had pleural fibrosis or calcification; evidence suggests that some men had pleural abnormalities due to asbestos exposure in childhood. Among men with lung field abnormalitties, 51 had rales and 11W had finger clubbing. Lung function factors most impaired by lung field abnormalities were forced vital capacity and carbon monoxide transfer factor. There was considerable impairment of lung function in smokers compared to nonsmokers. Lawther, P.J., Asbestos: some nonradiological aspects., Proc. Roy. Soc. Ned., 64 (8): 833-834 (1971).

ASBESTOS; OCCUPATIONAL EXPOSURE
A brief overview of asbestos and asbestos-related-diseases, asbestosis, cancer, and mesotheliona is presented. Although greatest exposure to asbestos is likely to occur during industrial processing, asbestos is also an environmental pollutant. Research is in proqress to determine the mechanism of asbestos carcinogqnicity. Rats were injected intraperitoneally with asbestos and the tumor of Walker in a leg muscle. Controls receiwed either the asbestos, the tumor, or a saline solution. At autopsy, the tumor in animals wh-ich had received both asbestos and tumor was significantly larger and more ulcerated than in the controls. Splenonegaly was found in this group also, but not in the controls. The reticulo-endothelial system any have participated in increased growth of the tumor. Infrared absorption was used to differentiate between different serpentine minerals--thrysotile, lizardite, and antigorite. When combined with x-ray diffraction, the method is very useful, but certain mixtures cannot be identifted by this procedure alone.
A case report of a patient exposed to asbestos as an oil drum packer demonstrates the extre-nely rapid growth of a diffuse pleural mesothelioma. The disease was fatal three weeks from the onset of syaptons. However, chest roentgenograms taken three months prior to the onset of symptoms revealed no noticeable tumor. ASBESTOS; HUMAN; OCCUPATIONAL EXPOSURE; X-RAY: MESOTHEL IONA <193> Lumley, K.P.S., Asbestos dust levels inside firefighting helmets with chrysotile asbestos covers., Ann. Occup. Ryg., 14: 285-286 (1971).
Dust levels inside asbestos-covered firefighting helmets were determined by collecting samples in the breathing zone of the wearer on 0.8 um pore size 14illipore membrane filters. The fiber count was made using phase contrast light microscopy at 400! magnification with the following results: new helmet with unlined asbestos cloth cover -2.30 fibers/cm(3); old helmet with unlined asbestos cloth cover -1.38 fibers/cm (3); helmet with alunintsed asbestos cover -0.0 fibers/cm(3). The fire protection provided outweighed the small risk from asbestos dust inhalation. Aluminised asbestos cloth covered helmets were recommended. ASBESTOS: OCCU'ATIONAL EXPOSURE; INRALATION; HUMAN <1914> Lumley# K.P.S.; Harries, P.G.; O'Kelly, ?.J., Huildings insulated with sprayed asbestos: a potential hazard., Ann. Occup. Hyg., 14: 255-257 (1971) Crocidolite and amosite asbestos have been used as insulation on the walls and underside of the roofing of many storehouses attached to the Naval Dockyards in England. The sprayed-on asbestos insulation was easily damaged and much asbestos debris was present. Fiber counts wade by the Millipore membrane filter technique increased with increasing activity in the building and were In excess of the accepted standards of 0.2 fibers/cubic cm for crocidolite. Crocidolite values ranged from a mean of 0.26 fibers/cubic cm in little used buildings to a mean of 11.89 fibers/cubic cm when the fallen debris was disturbed. It was recommended that the insulation be sealed to minimize human hazards. ASBESTOS; CROCIDOLITE; STANDARDS; OCCUPATIONAL EXPOSURE; SHIPYARDS; HUMARN (195> Luxon, S.G., The use of dust respirators against asbestos dust hazards in the United Kingdom., Amer.
Ind. Hy. Assoc. J., 32(1): 723-725 (1971) . In the United Kingdon, the use of simple dust respirators against asbestos inhalation is limited to concentrations not exceeding 40 fibers/cc of air for chrysotile and amosite or 4 fibers/cc for crocidolite. Higher degrees of protection can be attained by using (1) the positive-pressure dust respirator in concentrations not exceeding 200 fibers/cc of air for chrysotile and amosite or 20 fibers/cc of air for crocidolite; (2) ultra-high-efficiency dust respirator in concentrations less than 800 fibers/cc of air for chrysotile and amosite and 80 fiber/cc of air for crocidolite. At dust levels above this, only a posttive-pressure airline respirator provides adequate protection. The inhalation of dust of any kind is potentially dangerous to the lungs. Experiments indicate that the most severe problems are caused by particles which are invisible to the naked eye. One industrial source of harmful dust is the processing and installation of asbestos; in Great Britain the Asbestos Regulations of 1969 deal with thia problem specifically. Limits for common asbestos are set at 2 fibers/cc or 0.1 mg/cubic meter; these may be altered as more information becomes available. Sampling instruments for measuring respirable dust in work areas are briefly discussed. More than 88% of the emplovees in the Ouebec chrysotile mining industry over 50 years of age were surveyed and rated by an exposure index. Overall mortality was lower than normal, but in those exposed to highest dust concentrations the rate was 20% higher. Respiratory, cardtovascular, and malignant diseases accounted for the excess. Talc, which may contain asbestos as a natural contaminant, is added to rice exported to Japan. Research has shown that ingestion of asbestos can increase the incidence of canter of the gastrointestinal tract. It is possible that this factor-contributes to tbe high incidence of stomach cancer among the Japanese. ASBESTOS; FOOD CONTAMINATION; CANCER; HUN&*; IWGESTION; GASTROINTESTINAL <200> Merliss, R.R., Talc-treated rice and Japanese stomach cancer., Science, 173: 1141Science, 173: -1142Science, 173: (1971. Evidence, both epidemiologic and analytical, is presented to support the hypothesis that the high incidence of stomach cancer in Japan Is due to the asbestos content of the talc which is used to coat the rice in the diet. Med., 21(4): 118-121 (1971).
Inhaled fibers become coated with an iron-protein envelope and are called ferruginous bodies. If the core fibers are identified as asbestos, they are called asbestos bodies. The asbestos body begins as a thin yellow beaded object and matures to a shorter thicker dark brown segmented shape. The coating becomes granulated, followed by fragmentation, and phagocytosis. Difficulty in recognizing these bodies, especially in later stages, may result in failure to establish a relationship between asbestos and mesotheliona. Minor constituents of chrysotile asbestos fibers (iron, chromius, cobalt, and scandium) were made radioactive by exposing the fibers to neutron irradiation. The fibers vere iniected intrapleurally in rats and traced to fcllow the dissolution of the trace metals and migration of asbestos. For chrysotiles in which cobalt substitutes magnesium in the brucite layer, the cummulative excretion of cobalt radioisotope was used as an index of magnesium dissolution; results showed that 25-35% of the structural magnesium in chrysotile dissolves in one month. Cobalt leached more rapidly than chromium which was detected in the liver and carcass at death. Leached iron was distributed in the liver, spleen, gut, blood and carcass, and scandius was found in all ttssues except the blood. Chrysotile was distributed mainly in the heart, lungs, diaphras and chest wall; however, in one case, a significant portion of the fibers had migrated to the liver via adjacent In Vivo studies support the findings of In Vitro studies which relate asbestos cancer to the trace metals present (chromium, copper, and nickel).
Asbestos was injected intratracheally into hamsters. Final autopsies, compared with controls, showhd increased hydroxyproline in 25% of the animals, and a 35% decrease in aryl hydrocarbon hydroxylase; 15% of the nickel and 30% of the chromium injected remained. Persistence of chromium and nickel may favor carcinogenesis. A high incidence of asbestosis (3H9 after 20 years exposure) was found in pipe coverers exposed to low concentrations of asbestos during the construction of ships; the earliest case was found after 13 years of employment. When compared to a comparable, non-exposed control group, asbestosis was 11 times more common amonq pipe coverers. Dust exposure had been near the recommended threshold-limit value of 5 appcf. These results indicate that orolonged exposure to low concentrations of asbestos is hazardous and support the need to lover the threshold-limit values. Clinical and roentgenoloqic findings are presented.
ASBESTOS; STANDARDS; ASBESTOSIS; PTPE COVERERS; OCCUPATIONAL EXPOSURE; SHIPYARDS; HUMAN <20s> Wavratil, M., Pleural calcifications due to asbestos exposure compared with relevant findings in the non-exposed population., Inhaled Particles III: Proceedings of an International Symposium. (London, 1970 X-rav examinations of workers exposed to asbestos dust for 10 years or more in a Czechoslovakian factory revealed a '.2% incidence of pleural calcification compared to 4.5% in relatives living in the vicinity of the factory. The occurrence of pleural calcification in 1.17W of the general population living 2 to 24 km from the factory indicates that asbestos exposure is only one of the possible causes. Research on mineral metabolism and serum proteins showed increased acid phosphatase activity, and higher levels of gamma globulin in calcification cases than in control. ASBESTOS; OCCUPATIONAL EXPOSURE; NON-OCCUPATIONAL EXPOSURE; HUMAN; PLEURAL CALCIFICATION; BIOCHEMICAL EFFECTS <20 6> Plamenac, P.; Pikula, B.; Kahvic, M.; Markovic, 7.; Selak, I.; Zeger-Vidovic, Z., Incidence of "asbestos" bodies in basal lung smear., Acta Med. Tugoslav., 25 (4): 325-332 (1971).
In Sarajevo, Yugoslavia, four smears were made from the cut surface of the bases of the lower lobes of fresh unfixed lungs in each of 100 consecutive autopsies. Asbestos bodies were identified by optical microscopy an& pseudoasbestos bodies were ionored. Smears from 38 of the 100 autopsies contained asbestos bodies, being positive in 52.7% of the males and 20% of the females. Asbestos bodies were found more freguently in older age groups of both sexes. One-hundred percent of males over 80 had asbestos bodies in their lungs. Guinea pigs, hamsters, and rats were exposed to asbestos dusts by inhalation, or by intratracheal, intrapleural, or intraperitoneal injection. For all three animals, a fibrotic reaction was produced by amosite, crocidolite, and chrysotile. Amosite produced the strongest reaction, especially in guinea pigs. Two pulmonary cancers developed in rats exposed to crocidolite. In the injection experiments, amosite produced no tumors, while chrysotile caused 5 mesotheliomas In rats, and crocidolite caused 6 in rats and rabbits. The relative importance of clinical, radiological and pulmonary function variables in evaluating asbestosis and chronic obstructive airway disease in asbestos workers., Clin. Sci., 41 (6) Asbestos is not only extremely useful but essential in some areas of modern industrial living. However, like so many other industrial products, it can produce adverse health effects if improperly handled. A general outline of asbestos emission sources and controls is presented. ASBESTOS; DUST CONTROLS; OCCUPATIONAL EXPOSURE; STANDARDS <21 0> Richards, A.L.; Badaii, D.V., Chrysotile asbestos in urban air., Nature, 234 (53241): 93-94 (1971). A new procedure for measuring chrysotile asbestos in air samples by x-ray diffraction was developed. Air samples taken near an asbestos textile factory indicated an asbestos content below the limit of detection, less than 0.1 ug per cubic meter. A more sensitive procedure is being developed. The exposure of peritoneal macrophages (guinea pig) to the UICC standard reference asbestos samples produced cytotoxic effects as evidenced by a reduction of 2,3,5-triphenyl tetrazol chloride in the cell (TTC method), permeability disturbance of the cell membrane (nigrosine method) and reduced cell oxygen consumption (polarographic method). Cbrysotile was the most cytotoxic asbestos variety, and crocidolite was considerably weaker. Luminescence studies indicated that grind ing asbestos produces significant structural changes, shifting the activation energies of electron traps of the samples; the relationship between this shift and resultant cytotoxic effects should be investigated further.  1249-1255, (1971).
A brief description of pulmonary diseases, including asbestosis is presented. The principal clinical symptoms of asbestosis--dyspnea, loss of weight and coughinq--occur 10 to 25 years after initial exposure. Pleural or peritoneal mesotheliomas and gastrointestinal malignancies have been associated with exposure to asbestos. The role contaminates may play in the carcinogenicity of asbestos is not A review is gtven of the incidence of lung cancer, pleural mesotheliona, peritoneal mesotheliona, other neoplasms, and asbestosis in asbestos insulation workers; lung cancer was more prevalent among workers who smoked. Although data are not sufficient, tumors of the hematopoietic and gastrointestinal systems may be associated with asbestos exposure. It appears that increased exposure increases the neoplastic risk; therefore it is hoped that appropriate industrial hygiene and environmental controls will minimize or eliminate these risks. Adverse health effects due to inhalation of asbestos fibers was once thought to be restricted to asbestos workers. In the past several years much evidence has accumulated to indicate that the ambient air, especially in urban areas, may contain enough fibers to be of concern. The use of new techniques, such as electron microscopy, to detect fibers in lung sections has revealed much higher levels present in city dvellers than was previously suspected. Resolution of this question is hampered by the long lapse between asbestos exposure and appearince of related respiratory disease. Five standard samples of different types of asbystos fibers were analyzed by electron diffraction. The patterns obtained were specific enough to identify each type, though the Rhodesian and Canadian chrysotiles apparently were identical. Fiber orientation did not have a significant effect on diffraction patterns. Pistochemical staintng and electron microscopy were used to investigate the presence of actd phosphatase in guinea pig granulomas formed by the intrapleural inlection of asbestos dust. The majority of granuloma cells consisted of macrophages and giant cells that phagocytosed large amounts of dust; a few were fibroblasts containing only small numbers of dust particles. The acid phosphatase reaction was confined to the lysosome organelles of these cells; but in the macrophages and giant cells, fever than 50 of the primary lysosomes and 10 of the phagosomes were positive for acid phosphatase.
Fibroblasts, however, contained the enzyme in both primary lysosomes and phagosomes in most cases. It was concluded that since macrophages and giant cells phagocytose large numbers of particle, phagosomes outnumber the lysosomes so that only a small portion of phagosomes can contain lysosome enzyses. The first case of lung fibrosis resulting from exposure to asbestos dust was reported in 1907. Bowever, the relationship between asbestos inhalation and fibrotic lung disease was not established until the late 1920's. The association betveen asbestosis and cancer vas first suggested in 1934, but the relation between asbestos exposure and mescthelioma was not determined until 1960. Preventive legislation for controlling dust exposure is the only known solution to these health problems since no treatment has been developed. The present knowledge of asbestos related diseases is summarized concisely. Sluis-Cremer, G.K., Massive fibrosis in asbestosis., Environ. Res., 4: 430-439 (1971).
A study of asbestosis In 4 South African asbestos miners revealed several pathological patterns corresponding to fibrotic lesions seen in x-rays: (1) diffuse hyaline fibrosis vith elastosis and areas of concentric fibrosis; (2) diffuse hyaline fibrosis with areas of concentric fibrosis; and (3) diffuse hyaline fibrosis vith areas of concentric fibrosis, necrosis, and calcification. All of the miners were exposed to high dust concentrations for more than 10 years. The etiologic role of many factors remains unsolved. Between 1963 and 1969, 28 cases of malignant pleural mesothelioma were observed in dock workers in the Vilhelmshaven area. A majority of the workers had been occupationally exposed to asbestos on the old docks, thus suggesting a possible relationship between asbestos and mesothelioma.  154-155 (1971).
A method for measuring ambient concentrations of airborne asbestos involves the reduction of fibers to fibrils by ultrasonication with subsequent identification and quantification by electron microscopy. Preliminary air analyses by this method indicate that asbestos levels are approximately 2 ug/cu a at a point source, 0.5-15 ng/cu a at urban sites, and 0.1 ngVcu m at non-urban sites. Differences in fiber diameter among various asbestos types affect the free-falling speed and ease of penetration to the lung and pleural tissues. As determined by electron microscopy, the mean disnter is 0.073 um for Northwest Cape crocidolite, 0.212 us for Transvaal crocidolite, and 0.2113 ua for Transvaal amosite. The fiber length in all varieties was proportional to the diameter. Because of their greater aerodynamic size, more Transvaal fibers can be deposited in the larger airways by gravitational settltng and inertial tipact, but due to interception in smaller airways, penetrate the periphery of the lung less efficiently than shorter Northwest Cape fibers. Two series of experiments resulted in preparation of chrysotile asbestos fibers labeled with tritium. Preparation of a synthetic material from MgO, SiO2, and tritiated water formed a partly non-acicular product. Natural fibers were maintained in the presence of tritiated water for 20 days at 300 degrees. Well-labeled acicular material was produced. This labeled dust was used to accurately localize the material in lung tissues by radioautography. Lung clearance of the dust could be quantified by scintillation counting. ASBESTOS: CHRTSOTILE; LUNG <227> Ulrich, P., Pathological anatomy of hyaline pleural plaques., Pneumonologie, 146(3): 19q-177 (1971).
Histological study of 10 cases of pleural plaques showed no asbestos fibers. Plaques consist of hyalinized fibrin layers covered by mesothelium and are difficult to recognize in an ordinary x-ray examination. A search for asbestos bodies in lung tissue from 100 necropsies in a London hospital revealed a progressive increase in the incidence from O in 1936, to 3% in 1946, 141 in 1956 and 20% in 1966. This rate of increase was correlated with a model which assumes that exposure is proportional to the total amount of asbestos imported Into the area after 1936. ASBESTOS; ASBESTOS BODIES; LUNG; HUN N Environmental Health Perspectives <229> Wagner, J.C., Induction of experimental tumors of the pleura by fibers (asbestos)., Oncology: Proceedings of the 10th International Cancer Congress (1970); R. t. Clark (Editor). Chicago, Tllinois., 2: 4416-51 (1971).
Various factors involved in the induction of tumors by asbestos were investigated in rats. All asbestos varieties, including samples purified by the removal of oils, produced mesotheliomas when intrapleurally injected. Finely ground samples produced the highest incidence. The inhalation of asbestos produced an excess of lung adenomas in rats; apparently, inhaled dust did not penetrate to the mesothelial surface. It is possible that immune-complex deposition may be related to the inmuno-pathogenesis in some cases of fibrosing alveolitis. In 33 cases of fibrosing alveolitis, immunofluorescence gave evidence of antibody formaticn in plasma cells. In 7 cases macrophages contained both inmunoqlobulin and complement. In 6 cases antibody and complement were deposited in alveolar capillaries. These findings were compared with those found in cases of entrinsic allergid alveolitis, asbestosis, and other chronic lung diseases. ASBESTOS; ASBESTOSTS; MACROPRAGE; FIBROSIS <232> Weiss, W., Cigarette smoking, asbestos, and pulmonary fibrosis., Amer. Rev. Resp. Dis., 104: 223-227 (1971).
A statistical analysis was made of 100 textile *orkers for which data on years of exposure to asbestos, duration and amount of cigarette smoking, and radioloqical evidence of pulmonary fibrosis vas known. The results clearly indicate that both asbestos exposure and cigarette smoking are causative factors of fibrosis; the incidence was significantly higher in workers who were heavy smokers. The sample population was too small to determine if the effects were simply additive or were synergistic. No significance could be attached to sex or age in this study.

ASPESTOS; FIBROSIS; SMOKING; RUMAN: INHALATION;
CO-CARCTNOGEN (23 3> Whitwell, P.; Rawcliffe, R.M., Diffuse malignant pleural mesothelioma and asbestos exposure., Thorax, 26: 6-22 (1971). Between 195S and 1970, 52 cases of pleural mesotheliona were diagnosed in patients at three hospitals in Merseyside, Eng and. In 60f of the cases, diagnoses were made f*om histological finainqs before death. Th1tunors were classified as tubulo-papilldry (20 cases), sarcomatous (11 cases), undifferentiated polygonal (3 cases), and mixed (18 cases). Occupational exposure to asbestos was established in 80% of the cases, with the most common employments being shipbuilding and repairs for men and sackware repairing for women. The Asbestos workers of today are not under the health risk of previous times. In the United Kinqdom, improvements in factory conditions in 1931 probably reduced the risks somewhat. However, asbestos was not recoqnized as a carcinoqenic agent until 1955; since then, it has been established as a cause of peritoneal and pleural mesothelionas. The presence of asbestos bodies in lungs cannot be regarded as a prelude to asbestosis or mesothelioma. Better control of industrial asbestos dust betweon 1924 and 1963 has delayed deaths from asbestosis and allowed time for various lung tumors to develop; this probably accounts for the recent increased mortality from lung cancer and mesotheliona in asbestos workers. Cigarette smoking may contribute significantly to the cancer incidence among asbestos workers. The risk of asbestos worker-smokers dying from lung cancer is eight times greater than for smokers who are not exposed to asbestos.
Contaminants in asbestos, such as trace metals and oils may be co-carcinogens and should be investigated further. A survey of occupational respiratory disease in Prance shows a high incidence of asbestosts due to large asbestos production increase after the war and unsatisfactory working conditions in textile industries. In 1962, a total of 94 textile workers in the entire country received compensation for asbestosts; by 1969, 89 workers out of 600 from one plant alone were pensioned. Since French law does not recognize lunq carcinoma, pleural mesothelioma, or tuberculosis as occupational disease, the incidence of these disorders generally has not been investigated in the 14,000 workers employed in all asbestos inAustries. Random incidents reported inclu6e 6 cases of lung carcinoma in textile workers exposed to asbestos for 30 years, and some cases of mesothplioma. No asbestos bodies were found in basal lung smears from 138 urban Inhabitants. Med., 37((4): 492-500 (1970).
Clinical, roentgenographic, and lung function studies were conducted on 598 asbestosis patients; 208 (35 percent) had reduced vital capacity; of these,-172 (29 percent) had functional abnormality suggestive of interstitial pulmonary disease. 100 workers (17 percent) had abnormal chest roontgenograms (grades 2 or 3). Parenchymal fibrosis was premnt in 45, pleural lesions in 37, and both of these were found in 18 subjects.
Reduction of vital capacity preceded grade 2 or 3 roentgen abnormality by 10-15 years. Grade 2 or 3 roentgen abnormality usually developed after 20 years of exposure. With 30 years exposure the incidence of functional and radiographic abnormalities was approximately the same. In 16.8 percent of workers with grade 2 or 3 parenchymal fibrosis there was no decrease in vital capacity. Analysis of soils from a Bulgarian agricultural region with dispersed asbestos outcroppings yielded fibrous minerals (anthophyllite, tremolite and sepiolite) in considerable quantities. Pleural plaques occur in the endemic human population. in areas devoid of mtcroppings the farming population was free of pleural plaques, and soil samples were devoid of asbestiform minerals. Pleural plagues seem to be prevalent in two population groups: those with occupational or residential exposure i.e., manufacture or mining of asbestos, and agricultural populations endemic to areas having natural out-croppings of asbestos or soil containinq the mineral fibers.
Chrysotile dust injected intrapleurally into guinea pigs (25 sqm, rats (25 mg), and mice (10 mg) produced large intrapleural granulomas. Examination of these granulomas disclosed additional information about asbestos body formation. Macrophages and giant cells secrete acid mucopolysaccharide which is adsorbed by asbestos fibers, forming a thick coat; the coatino subsequently becomes-impregnated with ferruqinous granules from the surrounding cytoplasm. Although mucopolysaccharide is actively secreted in young granulomas, free dust fibers are not coated; this occurs only when a fiber is partially surrounded by a single macrophage or by partially fused macrophaqes durinq qiant cell formation. Once cell fusion is complete, the asbestos body is completely intracellular, and mucopolysaccharide secretion ceases.
Giant cells readily form and surround dust fibers in quinea pigs, and less readily in mice. Since few giant cells form in rat granulomas, dust fibers can not be surrounded, so that asbestos bodies do not form. Thus, species differences in the ability to produce asbestos bodies may be due to differing cell behavior in asbestos qranulomas. Chrysotile and crocidolite dusts injected intrapleurally produced large granulomas in mice, rats, and guinea pigs; however, histological patterns of the lesions varied. In all cases, granulomas were eventually replaced by fibrotic tissue. Electron microscopic evidence indicates that pleural aranulonas induced by asbestos dust constitute the same tissue response and cell types involved in lung tissue reaction to asbestos. Individual macrophages, giant cells, and fibroblasts are identical, structurally and behaviorally, to those in lung granulomas. Berrylium, ferric iron, and chromium exerted no effect. However, the trace metals extracted from chrysotile (nickel, cobalt, chromium and manganese) reduced enzyme activity by 73%. Since unmetabolized BP in lung tissue is carcinogenic, trace metal inactivation of the uP hydroxylase enzyme slows BP metabolism and increases the carcinogenic risk. These results support the hypothesis that asbestos-related cancer actually may be induced by associated trace metals that interfere vith BP detoxification. (1970) Bronchial carcinoma causes the death of one out of 12 men in this country. Agents capable of inducing bronchial carcinona-particles of chrome and nickel ore, mustard gas, arsenic, asbestos, coal tar, ionizing radtations (radon, x-rays), and cigarette smokeare reviewed. Bronchial carcinoma is no more preventable in the full sense of the word than any other type of cancer; however, it is possible to reduce the risk of developing the disease. .R.A Shapiro (Editor). Oxford University Press, Nev York., 1969: 13-17 (1970. Underground and surface dust surveys made in South African asbestos mines and fiberizing plants at various intervals during a 24-year period  show that dust concentrations of chrysotile and amphibole asbestos were excessively high before 1967, particularly due to increased production rates after 1963. Between 1964 and1966 thermal precipitator samples representing 14,00 persons exposed to amphibole dust produced a mean count of 60-2000 particles per cubic cm (ppcc) per mine, and a total mean of 360 particles and fibers pcc. During 1968 to 1969, 84 samples taken from 90W of the exposed persons produced a mean count of 237 fibers plus particles/cc with a mean range per mine of 72-320. Thirty-four thermal precipitator samples representinq 1 500 persons exposed to chrysotile dust averaged 750 fibers plus particles/cc and a mean range per mine of 120-2000 during 19611-1966; precipitator samples from 55% of exposed persons from 1968-1969 averaged 370 fibers plus particles/cc with a ranqe per mine of 97-S00 fibers plus particles/cc. Clinical, radiological, and sputum examinations were performed on 347 workers from a plant that manufactured asbestos-concrete pipes. The high incidence of respiratory abnormalities was attributed to high dust exposure in the plant.  Radiol., 21: 355-365 (1970). A radioloqical study of 484 men with signs of asbestosis acquired in shipyards and engineering workshops at Barrow-in-Furness was conducted to determine the earliest diagnosable lesions. Results Indicate that pulmonary fibrosis is an early siqn of asbestosis in heavily exposed men, but is difficult to diaqnose because early changes merely are exagerations of normal lung markings; diffuse pleural thickeninq is a non-specific sign attributed to asbestosis only by excluding other diseases. Although pleural calcification is the most striking and characteristic lesion in asbestosis, it usually requires at least 20 years to develop. The earliest appearance of fibrous pleural plaques can be detected by careful radiologic study, and is diagnostically reliable in the early detection of asbestos-related disease. ASBESTOSIS 204-208 (1970) Out of 97 pneumoconiosis cases attributed to occupational exposure in Rhodesian chrysotile mines from 1963-1967, 39 cases were diagnosed as asbestosis; 118 showed radiological evidence of tuberculosis, with or without asbestosis.

Rinety
Asbestosis lesions appeared mainly in the middle and lower parts of the lung, whereas tuberculin lesions developed in upper lung areas. In tuberculosis patients, the disease became manifest before 16.c years of employment. Asbestosis developed after a longer duration of exposure. Radiological tests showed the frequent presence of nodules and qround glass appearance of the lung tissue, but these were not specific for asbestosis. Emphysema occurred in 2 asbestotic patients. The "shagqy heart" appearance was found in only 2 cases, and pleural thickening with or without calcification, occurred In 4 cases. No lung cancer or pleural mesotheliona was observed. The standard permissible dust levels in Rhodesian mines is a maximum of 300 particles/cc, including particles no longer than 5 microns and fibers no longer than 40 microns. Gerber, 4.A., Asbestosis and neoplastic disorders of the hematopoietic system., Amer. J. clin. Pathol., 53: 204-208 (1970). Autopsy findinqs in 35 asbestosis cases revealed the association of five cases with tumors of the hematopoietic system. The incidence of this association is significantly higher than the overall incidence of such disorders in the corresponding age group of patients without asbestosis.  173-176 (1970).
This interim report describes current progress in data collection efforts concerning-the incidence of asbestos-related diseases in the United Kingdom.
Since 1966, mesotheliona of the pleura or peritoneum has been recognized as a prescribed Industrial Disease. The Register of Mesotheliomas, established in accordance with the Tnternational Union Against Cancer, recorded an increase in the cummulative total of mesothelioma cases from 11 in 1962 to 550 by 1968. A 10% sample of 1504 asbestos workers in Devonport Dockyard revealed a 4.5% incidence of pulmonary changes related to asbestos exposure; in most cases the qffects were limited to pleural thickening. A study of 3,860 chest clinic patients An intensive postmortem study was conducted on 7 mesothelioma patients with pulmonary asbestos bodies. The common occurrence of asbestos bodies, fragments, particles and dust in the. hilar node, mediestinal node, pleural lymphattcs, spleen, abdomen, and intestinal sucosa indicates that asbestos is transported in macrophages through lymphatic channels and blood, and is widely distributed in the body. Asbestos is irritating, mechanically and chemically, causing fibrosis and malignancy. This may be due to the effects of iron compounds, such as hemostderin or ferretin, in the asbestos body coating. The authors examine the various theories concerning the pathogenesis of asbestos. The authors also describe feeding experiments in which rats were fed 5% asbestos by weight of food. After 21 months, asbestos-fed animals were not significantly different in weight than control animals fed on same diet without asbestos. They question previous results which report transportation of fibers within the body. synthetic chrysolite evokes a reaction analagous to that of a biologically inert dust. Lung cancer developed in 25 (35%) of 72 rats that survtved 16 months of chrysotile exposure for 6 hrs a day, 5 days a week, at concentrations of approximately 86 mg per cubic meter. Adenocarcinomas (71%), squamous cell carcinomas (145) and fibrosarcomas (25S%) were the tumor types found. tunq cancer did not develop in hamsters and guinea pigs exposed simultaneously. Prior to dust exposure, 31 out of 72 rats had received intratracheal applications of 5% sodium hydroxide to impede the lung clearance of dust; lung cancer incidence was significantly higher in this group (48%) than in the remaining 41 rats (24) . Preliminary evidence from in vitro studies with hamster fibroblasts indicates that collagen production increases when supernatant soluttons from quartz-treated macrophages were added to fibroblasts. It is felt that this experimental approach may prove valuable in further studies of the fibrogentc effects of asbestos in the lung.
Pleural mesothelioma occurs frequently enough to be considered in the differential diagnosis of chest tumors. Correct diagnosis is difficult to establish, and often is determined by needle biopsy or open thoracotomy. A bistory of asbestos exposure should be suspect. The significant radiologic signs are (1) pleural effusion, (2) irregular, nodudular, pleural thickening, and (3)  Hitchcock, H.T., Mesothelioma of the pleura., Irish J. Red. Sci., 3(10)to 453-U56 (1970).
Pleural mesotheliona has been diagnosed much more frequently in the last ten years than previously; most tumors have occurred in 110-60 year old males with a history of asbestos exposure. Basically, asbestos exposure must be long (at least 9 or 19 years) and the fiber size must be small enough to be respirable for mesothelionas to occur and even then it cccurs only rarely. cigarette smoking also may be required. Three case histories of pleural mesotheliomas were reported, none of which had any known asbestos exposure. Radiotherapy is the best treatment for pleural mesothelioma at present but at best merely delays the fatal outcome. Cytochem., 3(4); 197-198 (1970).
Silicosis or asbestosis was induced in rats by pertracheal infusion of free silica or blue asbestos suspension. After 2,4,8 or 16 weeks S35-methionine or H3-glycine was injected intraperitoneally. One hour following injection animals were sacrificed and radioautograms obtained of lung tissue.
S3S-methionine was found in the extracellular space around nodules of the lungs with somewhat less uptake in the case of silicosis. R3-glycine was taken up to a small extent 2 weeks after infusion and then uptake increased. More R3-glycine was taken up in lungs with asbestosis than with si licosis.  , pp. 190-191 (1970). The mortality epidemioloqy of anthophyllite asbestos miners was followed in Finland from 1936-1967; the study included more than 1000 people who were exposed for durations ranging from 3 months to more than 20 years. Causes of death for 33 cases with exposure longer than 10 years were carcinoma of the lung (8), gastrointestinal carcinoma (21, ashestosis and cor pulmonale (9), asbestosts (2), cardiac (8), cerebral (l) , and others (4) The mainb halzards of exposure to other asbestos dusts are pulmonary asbestosis, lung cancer, and pleural or peritoneal sesothelioma. Asbozurite and sovelite are widely used thermo-insulating materials containing 15% asbestos. Clinical examinations of 158 factory workers exposed to these materials for more than 6 years revealed only 9 cases of pneumoconiosis; these vorkers had been exposed for 13-22 years. Intratracheal administration of 50 mg.asbozurite in 0.5 mg physiological saline to rats produced lung nodules after 3 months; the nodules were surrounded by collagen fibers and resembled an early stage of silicosis. 'O mg sovelite dust produced hyperplasia of lymphoid apparatus, desquamation of bronchial epitheltum moderate sclerosis around the bronchii, but no fibrosis. The dusts of bozurite and sovelite are less fibrogenic than dusts of chrysotile asbestos due in part to their low asbestos content. Asbozurite is more fibrogenic than sovelite. Based on clinical and experimental evidence, the proposed maxioum permissible concentrations of asbozurite and sovelite in factory air are 5 mg/cu a and 8 mg/cu a. The evaluation of hazards from asbestos-containing materials should not be made solely on the basis of the asbestos content. Preliminary results indicate that the electron microprobe may be used to identify and characterize asbestos fibers and bodies in human lung tissue. It enables analysis of material in the area of large particles to gain information concerning biological interaction. Prom this technique it is possible to establish presence of specific asbestifors materials for long periods after exposure. Electron microprobe analysts is a valuable technique for identifyinq all types of asbestos fibers in asbestos bodies. It combines the use of scanning electron microscopy and x-ray spectrometry to detect x-ray emissions which reflect the characteristic bulk Fe-Hg-Si-Na-Ca content of each asbestos type.

ASBESTOS; ANTHOPHYLLITE
The method provided unequivocable identification of amosite asbestos cores in asbestos bodies from workers exposed to amosite. The data show that amosite fibers remained chemically unaltered and intact after at least 10 years of residence in the lung. The most accurate analyses were obtained for exposed fibers and thin-coated linear bodies which produced characteristic amosite emissions. Curvilinear and thick-coated bodies yielded high Fe emission values which obscured the chemistry of the fiber core. The analysis of chrysotile bodies from the lungs of chrysotile workers was more difficult because of changes in fiber chemistry (depletion of magnesium and addition of iron) which probably result from biochemical interactions in the lunq, and the tendency of chrysotile to split into fine fibrils not visible by optical microscopy. The most accurate detection was made with thin bodies having little or no coating. ASBESTOS; CHRYSOTTLE: AMOSITE; ANALYSIS; ASPESTOS BODITES; X-AY; HUMAN <277> Litterst, C.L.; Lichtenstein, E.P., Toxicity of BeLa cell growth medium after passage throuqh asbestos filters., Lab. Pract., 19: 1221-1223(1970. ReLa cell monolayers grown in culture normally replicate within 24 hours. When qrown in medium that had been filtered through an asbestos pad (0O.u) in a Seitz apparatus the replication time was significantly increased. ASBESTOS; CELL CULTURE; CYTOTOXICITY <278> nackenzie, P.A.?.; Barries, P.G., Changing attitudes to the diaqnosis of asbestos disease., J. Boy. Wav. ned. Serv., 56: 116-123 (1970).
Pleural abnormalities have bean found in many dockyard workers in Plymouth, England. These include fibrosis, hyaline plaques, diffuse pleural thickening, linear pleural thickening, pleural calcification, effusion, and pleural mesothelioma. Young men with about 15 years exposure to asbestos have the most extensive pleural reactions sometimes accompanied by effusion. A modified radiological technique to detect pleural abnormalities is described. The progress of the pleural changes will be followed over a period of years. The incidence of fatal malignant sesothelial tumors was approximately 1 per million per year between 1959 and 1968 in Canada, with a total of 165 cases. An association with definite or probable occupational exposure to asbestos was clearly demonstrated in only 20% of the male cases and 1 of the female cases; the occupations associated most frequently with these cases involved textile manufacture, installation of brake linings, and insulating, rather than mining or milling. go association was found with residential exposure in asbestos mining areas. In a retrospective study of the incidence of mesothelioma in Scotland from 1950-1q67, 80 cases were traced from pathology reports and biopsy material of malignant peritoneal and pleural tumors.
Occupational and residential patterns were recorded, as well as the degree of asbestos exposure. More than twice as many mesothelioma cases reported residential and occupational exposure to asbestos than did not. Asbestos exposure usually originated in the shipbuilding industry. Between 1958 and 1967, 103 asbestos workers from a crocidolite mining area in Australia developed pneumoconiosis. The length of exposure before the develcpment of disease was 1-14 years for mill workers and 3-12 years for underground workers. Silicosis was prevalent in miners, while asbestosis with massive lung fibrosis, asbestos bodies, finger clubbing and basal crepitations was more common in mill workers, although both diseases occurred in each group. No pleural plaques were observed; 6 workers developed bilateral pleural effusions. The incidence of death and disability related to occupational pneumoconiosis and cancer was higher in mill workers than in miners'. The mean age of 50 lung cancer cases and their control pairs was 63 years. There were 46 men and women in each group. Asbestos bodies vere found in the lungs of 80 (80%) lung cancer patients and 32(64%) of the control group. Statistical analyses showed no significant association between the statistical analyses showed no occurrence of asbestos bodies in the lungs and cancer of the lung. Clinical observations at the University of Milan revealed that the incidence of pleural calcification was 1.41% in 143 subjects with tuberculosis, and 1q.2( in 43 patients with asbestosis. In asbestotic patients with pleural calcification, the duration of exposure to asbestos and the latent period from initial exposure to the development of calcification vas at least 15 years. most asbestotic calcifications were bilateral, multiple, diffuse, small, homogenous structures with distinct, sinuous outlines. Tubercular pleural calcifications were monolateral, localized to the costal pleura, large with granular structure, markedly opaque and irregular in outline. This article describes three integrated clinical studies which attempt to establish the incidence of asbestos in the lungs of the general population In England, Ireland, Northern Europe and Finland. Results show a significant increase in the incidence of asbestos bodies over the last 40 years. Investigation of methods for detecting asbestos bodies and fibers in lung tissue indicate that the potassium hydroxide digestive technique was the most efficient, reliable extraction process, whether the extract was examined optically or by electron microscopy. ASBESTOS; ASSBSTOSIS; ASBESTOS BODIES; LUNG <289> Pylev, L.N.; Roe, F.J.C.; Vorvik, D., Study of the distribution and isolation of (3H)benz(a)pyrene from the animal orqanism after its intratracheal inlection with asbestos and carbon black., Top. Onkol., 16(3): 61-69 (1970).
Following intratracheal treatment of hamsters with labelled beoz(a)pyrene (BP) or combinations of BP with asbestos or carbon black, radioactivity was eliminated rapidly from the lungs dur,ng the first 2 weeks, regardless of treatment. After 21 days, however, lung tissue of hamsters treated with asbestos or carbon black and BP retained the most radioactivity. Levels of radioactivity in other organs were similar in all groups. Twenty cases of diffuse pleural mesothelioma were found in 6406 adult necropsies (0.39) between 1950-1967 at a hospital in Glasgow, Scotland. Shipyard work was the main occupation in the urban area served by the hospital. Fifteen of the cases were found in the second 9 year period. Sixteen were men and 19 were middle aged or older. Pleural effusion was the most common finding at the first examination. The tumors only rarely materialized but commonly invaded surrounding structures. Eleven of the 20 tumors were epithelial, 6 were of mesenchymal type and 3 mixed. Asbestos bodies were found in the lungs of IR of the cases and histological evidence of asbestosis was found in 13 cases.  Thorax, 25: 270-284 (1970). Pleural plaques were observed in 644 (6.69) out of 9,760 photofluorograms taken in 1965 in a sparcely populated Czechoslovakian district. The highest incidence occurred between the ages of 66-70 years. The disorder was found mainly in farmers, and familial incidence was common. The etiologic aqent of the disease is unknown; geological surveys of the region show no evidence of naturally occurring asbestos, and there are no asbestos industries located within 100 km. This appears to be an endemic disorder caused by an unknown agent which is carried to the pleura through the lymph and blood. ASBESTOS; RUMAN; PLEURAL PLAQUES (293) Schnitzer, R.J.; Bunescu, G., Polymers as selective antagonists of hemolytic asbestos fibers., Arch. Environ. Health, 20: 481-482 (1970).
The exposure of chrysotile to high temperature (1000 degree C) alters the structure, converting it to a dehydroxylated magnesium silicate product. Althouqh both heated and unheated chrysotile possess hemolytic properties, their lytic activities differ since they are antagonized by the selective action of different polymers: polyvinylpyridine-N-oxide inhibits hemolysis of sheep RRC's by heated chrysotile, whereas carboxymethyl antagonizes the hemolytic effect of unheated chrysotile. This suggests that heated asbestos may produce different pathological effects than the unheated form. CHRTSOTILE; REMOLYSTS; ASBESTOS; SHEEP; CYTOTOXTICITY <2941) Schnitzer, R.J.; Pundsack, F.L., Asbestos hemolysis., rnviron. Res., 3: 1-3 (1970). Asbestos fibers, principally chrysotile, caused marked hemolytic activity on sheep red blood cells (RBCs); however, amphibole ashestiform fibers such as crocidolite, amosite, tremolite, and anthophyllite were hemolytic to a negligible degree. These results sugqest that the chemical nature of the fiber surface, and consequently, the surface area of the fiber, determine the hemolytic capacities of asbestos. The minimal concentration of chrysotile necessary to cause at least 509 hemolysis decreased with increase in surface area.
Hemolysis was inhibited by substances that were strongly adsorbed by the fibers. EDTA inhibited hemolysis by chrysotile, but other chelating and complexing agents did not. Repeated contact of chrysotile with red cells also eliminated hemolytic activity, possibly due to the adsorption of some cell components on the fibers.

Shapiro (Editor). Oxford University Press, New
Tork., pp. 225-232 (1970). clinical and epidesiological investigations in South Africa between 1956 and 1968 revealed a high incidence of mesothelioma and carcinoma in Worth West Cape inhabitants (1t41 cases, including 111 cases of mesothelioma). In addition, there was a marked association of tuberculosis with mesothelioma in family groups of all races. It is suggested that air pollution by asbestos may synergistically affect MYC0BACTERIUM TUBERCULOSIS, thereby inducing mesothelioma and carcinoma. The dry climate of the area may produce a variety of dusts which contribute to the pulmonary disease problems. Clinical experience gained in the United Kingdom factories that manufacture asbestos products indicates that early diagnosis of asbestosis in workers requires accurate history of exposure, serial x-rays at intervals of 1-2 years followed by investiqation of abnormal findings, and surveillance of clinical findings, physiologic lung function, and sickness absence records. There are no clear-cut signs or symptoms of physiological abnormality in early stages of asbestosis. A retrosuective radiological study of 23 pleural sesothelioma cases in South Africa showed 7 cases with signs of asbestosis, 5 with parenchymal lung changes, 7 with noncalcified pleural changes, 2 with pleural calcification, 14 with pleural effusion, 15 with lobular pleural tumors, and hilar mass associated with pleural tumor in 6 cases. All patients were engaged in asbestos mining, or lived in a mininq and milling area. Compared with previously reported cases, there were no significant age or sex differences.

190-192 (1970)
A retrospective study was done on 413 cases of deceased asbestos workers who had received chest x-rays during their working lifetime. Presented briefly are clinical observations of pleural changes, calcified and non-calcified pleuiral plagues, and radiological changes associated with asbestotic fibrosis (pneumonitic, coarse, and massive fibrosis). The fibrogenic effects of asbestos and other dusts may be determined by the length and crystalline structure of the fibers or particles. Clinical observations confirm that asbestosis is more common in workers employed in the spinning and weaving of asbestos than in other processing Procedures. Although total particle densities may be higher in other asbestos occupations, the density of long fibers used in weaving and spinninq is greater. In guinea pigs treated interbronchially with 60 mg of chrysotile fibers (5 or 10 microns long), fibrotic changes predominated in the bronchi and parabronchial tissues and were most extensive in animals treated with long fibers. 'olloving the administration of crystalline (fibrous) or amorphous chrysolite to guinea pigs, only the crystalline fore induced pulmonary changes indicative of asbestosts. Oxygen demand and consumption in lung sections from mice were increased by crystalline chrysolite, amorphous chrysolite and crystalline quartx, but not by fiber glass or fine glass. Intravenous administration of crystalline chrysolite and quartz in rabbits produced an increase in serum gannaglobulin; amorphous dusts of chrysolite and coal did not. ASBESTOSIS; ASBESTOS; PABBIT; MOUSE; GHINEA PIG; FIBROSIS; LUNG (303> Tabershaw, TI..; Cooper, W.C.; Balzer, J.L., A labor-management occupational health service in a construction industry., Arch. Environ. Health, 21(6): 781-788 (1970).
Tn the San Frrncisco area, lung cancer mortality rate is 8 times higher than expected among insulation workers with more than 20 years of occupational asbestos exposure. in 1966, Union and management organized an occupational health program of medical surveillance and industrial hygiene f or asbestos worlkers to develop guides for hygienic work practices, to promote early diagnosis of healtb. problems, and to counsel workers on health-related matters. The plan encompasses 13 Western U.S. states, and hopefully will minimize the incidence of asbestos-related diseases. Pulmonary occupational diseases are associated directly or indirectly with exposure to industrial dusts, powders, and minerals. The use of solid infrared spectroscopy greatly augments the use of x-ray diffraction spectra for identifying particulate matter. Qualitative infrared spectra are presented for actinolite, amosite, anthophyllite, crocidolite, tremolite, talc, chrysotile, and ether minerals.

138-141 (19701
Gravity and constant motion of the lung can induce a downward lateral movement of inhaled asbestos fibers which are too long to be phagocytosed; eventually, the fiber may penetrate soft lung tissue to posterior and lateral sites in the pleura and peritoneum. This hypothesis may explain the localization of asbestos fibers and pleural plaques at these sites. Pleural plaques develop by slow proliferation of fibroblasts and fibrocytes in connective tissue; pleural mesothelial cells are not involved in the formation, so that pleural adhesions are not developed in association with the plaques. Calcification is dystrophic, occurring in the center of older plaques where collagen is degenerated and devoid of nuclei. Though asbestos fibers are found in pleural plaques, the fibrotic response is not correlated with the number of fibers present, indicating that plaque formation may involve a sensitivity reaction.  Press, New York., pp. 28-36 (1970).

Compositional analysis of major constituents in T1CC
standard reference samples of asbestos show thatcrocidolite contains the highest concentration-of iron (15. 1%; the highest magnesium content was found in chrysotile (31-32w), and anthophyllite (24V).. Imosite and anthophyllite contained the-most silicon and silica dioxide. Chromium, manganese and nickel comprised the predominant trace constituents.
Rhode sian chrysotile had the highest chromium concentrations (1390 ppm) and the lowest manganese content (approx. 400 ppm). The highest manganese concentration was found in amosite (15,000 ppm).-Trace amounts of antimony were detected in amosite, crocidolite and chrysotile (less than 5 ppm), and the highest level of scandium occurred in crocidolite (less than 6 ppm). Other physical and chemical characteristics discussed include oil content, fiber length distribution, and electron diffraction patterns. The size and shape of asbestos fibers affect their deposition in the lung, and thereby determine the extent of penetration. The retention and penetration of straight fibers with small diameters (amosite, anthophyllite and crocidolite) is significantly greater than for long, curved fibers such as chrysotile. Curvature of the ftbers decreases the efficiency of penetration, especially in narrow passages where they are intercepted high ip the respiratory tract. However, the chrysotile fiber consists of bundles which tend to divide into numerous fibrils with small diameters; these can penetrate more deeply into lung tissue. The intercept mechanism also concentrates long fibers in narrow airways. Gravitational settlement and inertial impact cause shallow deposition of fibers with diameters of 3 microns or more; only fibers with smaller diameters succeed in penetrating pulmonary air sacs. Diffusion is a significant deposition mechanism for fibers smaller than 0.5  (1970).
Adverse biologic effects of asbestos fibers are closely associated with their physical characteristics. Comparative studies of aerodynamic behavior of asbestos fibers reveal that the sites and rates of deposition and retention in the lung are related to the fiber type. Asbestos fibers thicker than 3um are readily deposited in the upper respiratory tract and are unlikely to penetrate to the alveoli; however, thicker fibers of chrysotile may penetrate if they are fluffy and have low sedimentation rates. Deposition of a fiber by sedimentation depends mainly on the diamater; deposition by interception depends almost entirely on the length of the fiber. Because of their physical characteristics, chrysotile fibers are less likely than amphiboles to penetrate to the subpleural regions; amphibole fibers are a more favorably orientated by aerodynamic forces for penetration into the lunq. This could explain the large difference in the risk of sesotheliona in the asbestos mining areas of South Africa, in the crocidolite mines in the Worth West Cape Province there is a high incidence of mesothelioma, compared to a very low rate in the Transvaal, where both amosite and crocidolite are mined. Different studies are reviewed to support the conclusions.

120-125 (1970)
Both optical and electron microscopy were used to examine the size characteristics and distribution of resptrable asbestos in human and rat lung tissue. A chrysotile fiber is long and curved with an approximate diameter of 0.025 un. Amphibole fibers are straiqht with minimum diameters of 0.6 us for crocidolite, 0.15 ua for amosite; and 0.21 un for anthophyllite. Diameter distribution of the fibers in lung tissue may aid in identification of the asbestos type; studies of human lung sections from exposed individuals indicate that amphibole fibers from a given geographical location exhibits a characteristic diameter distribution (Cape Province crocidolite, Transvaal amosite, and anthophyllite from Finland). Fiber length affected deposition in a rat exposed to omosite; the fibers penetrating the terminal air sacs generally were shorter than those in air ducts. Interception is an efficient deposition mechanism for long fibers in small airways, and increases with decreasing airway diameter; therefore fibers in air ducts are longer than those which penetrate more deeply. Since the falling speed of a fiber depends more on diameter than lenqth, long fibers may penetrate deeply in with asbestos filler., Hyg. Sanit.,: 4156-458 (1970).
Asbestos molding compounds are used in the manufacture of phenoplasts for the hot molding of household and technical articles. They consist of phenol formaldehyde resin, asbestos filler and spectal additives. Tnhalation of dusts, phenol and formaldehyde vapors in work areas presents a significant health hazard in the manufacture of molding compounds and phenoplasts; recent surveys show extremely high concentrations of these in various factories. There is a serious need to reduce the concentrations of inlurious dusts (asbestos) and vapors by redestgning ventilation and exhaust systems, by improving manufacturing equipment and by mechanizing various aspects of the handling and transport of materials such as asbestos to minimize worker contact and air pollution in the factory. ASBESTOS; DUST CONTROLS; STANDARDS; OCCUPATIONAL VXPOSURE <311> Vigliani, R.C., Asbestos exposure and its results in Italy., Pneumoconiosis: Proceedinqs of the International Conference (Johanneshurg, 1969) . R.A. Shapiro (Editor). Oxford University Press, New York. , pp. 1q2-196 (1970). Between 1964 and1966, 586 new cases of asbestosis were compensated in Italy; 65W of the cases originated in Piedmont, Lombardy, and 20% in Liguria. The cement-asbestos and refractory industry accounted for 342 cases, while 101 cases represented dockyard and shipbuildinq trades. Only 20% of the cases were moderate or advanced stages of asbestosis. By 1969, a total of 1226 workers were receiving compensation ir Piedmont and Liguria. The main causes of death in compensated workers are asbestosis and cancer of the lung and pleura. The inhalation of asbestos dust is associated with the development of pleural and peritoneal mesothelionas in man. Experiments have shown that analagous conditions can be induced in rats. Results of experimental injection of chrysottle and crocidolite dust produced a high rate of tumors and extraction of the oil from the crocidolite had no effect; fewer neoplasms occurred with amosite.
In SPF and Standard rats injected intrapleurally vith 20 mg of asbestos dust, mesothelioma incidence was 30% and BOW for amosite, A4 and 69W for chrysotile, 59 and 68% for crocidolite; amosite produced fever mesotheliomas due to a longer initial period prior to tumor induction. In rats injected with 0.5, 1.0, 2.0, 4.0 or 8.0 mg of chrysotile or crocidolite, the incidence of mesothelioma was proportional to the dose injected, with chrysotile causing the highest incidence. In a third experiment, intrapleural injecticn of chrysotile samples from seven Canadian mines produced mesotheliomas. Mathematical models were used to calculate expected mortality and survival curves. Immunoloqical analyses detected antinuclear and/or rheumatoid factors in 47.5% of 80 patients who had a history of asbestos exposure; this represents a four-fold increase over the incidence in random populations. While the pathogenic role of these tissue antibodies is unknown, they appear to correlate vith severe, progressive, radiologic lung changes rather than to duration of exposure. Further study may determine the incidence of tissue antibodies in asbestos workers vith or without lung disease. ASBESTOS; RHEUMATOID FACTOR; ANTINUCLEAR FACTOR; HUMAN; RESPIRATORY DISEASE <316> Webster, I., Asbestos exposure in South Afrtca., Pneumoconiosis: Proceedings of the International Conference (Johannesburg, 1969). H.A. Shapiro (Editor). Oxford University Press, New York., pp. 209-212 (1970).
In South Africa, 179 cases of pleural mesothelioma were diagnosed as "definite mesotheliona" by 1969. In 61 mesothelioma cases confirmed by autopsy, asbestosis was found in 25; histological examinations showed 14 cases with no evidence of asbestosis or asbestos bodies, and X cases vith asbestos bodies but no evidence of interstitial fibrosis. In 148 cases of known occupational histories, 28 had not been exposed to asbestos. Pesults of the survey suggest that there may be no direct relationship between asbestos exposure and pleural mesothelioma. The direct carcinogenic cause may consist of more than 1 agent. The membrane filter method was used to collect dust samples from 73 different locations in more than 60 buildings constructed with asbestos or asbestos products. Fibers 5-100 u in length with a length/diameter ratio of at least 3:1 were counted.

ASBESTOSIS; CHRYSOTILE
Asbestos dust concentrations in over 9n% of the locattons sampled did not exceed one-tenth of the maximum accepted occupational exposure level. Forty-six percent of the samples tested contained asbestos levels similar to those found in buildings where no asbestos had been used in construction. Asbestos bodies were found in lung or hilar lymph node scrapings in 19 of 100 necropsies of Michigan residents. *In one case, asbestos bodies were found only in the hilar lymph node and in I cases, in both the lunq and hilar lymph node. In contrast, asbestos bodies were found in lung sections from only 4 of the 19 positive cases. The maximum number of positive results were found when the upper and lower lobes of both lungs were scraped. None of the subjects manifested pulmonary asbestosis duriwg life and, in general, did not have a history of asbestos exposure. There was no recognizable geoqraphical distribution pattern for the positive cases. ASBESTOS BODIES; LUNG; FERRUGIWOUS BODIES; NOW-OCCUPATIONAL EXPOSURE; HUMAN Environmental Health Perspectives <320> El-Sevefy, A.Z., Radiological findings in a cement-asbestos pipe factory., J. Egypt. Red. Assoc., 52: 836-844 (1969) . Chest x-rays of 317 workers in a cement-asbestos pipe factory shoved a high incidence of asbestosis, silicosis, or mixed dust pneumoconiosila. The number of positive cases and the varieties of radiological findinqs per case increased with duration of exposure, with 44% positive In workers with 5 years exposure and 81% positive in the 20 year exposure group. This factory had high dust concentrations and inadequate safety measures in the work areas.
Electrocardiograms of 29 patients with asbestosis showed left axis deviation in 9 cases (31%), and abnormalities in ventricular conduction in 16 cases (55%) due to complete or partial bundle blockage related to asbestosis cardiopathy. Radiological irreqularities in cardiac outline were associated with abnormalities in ventricular conduction. Asbestos is mentioned briefly in this review because it contains iron, nickel, and chromium. Nickel is the best documented metal carcinogen; more lunq cancer is found among workers in nickel mines or refineries than in the general population. The same result was found for British chromium workers. To a lesser degree, Iron has been suggested as a possihle carcinoqenic agent due to the higher incidence of lung cancer in hematite miners than in the general population. ASBESTOS; TPACE MEITALS; CANCER; TUMIOR; HUMAN <323> Gibbs, G.W., Some problems associated with the storage of asbestos in polyethylene bags., Amer. Ind. Hyg. Assoc. J., 30(1): 458-464 (1969).
The common practice of collecting and storing asbestos samples in polyethylene bags results in qreater quantities of oils in the asbestos than in samples stored in glass lars. A bright vellow component, identified as 3,3', 5,5' -tetratertiary butyl diphenoquinone, was found in the oils extracted from all asbestos samples collected in polyethylene bags. This compound presumably forms by some reaction between the asbestos and the polyethylene since it is not present in extracts of the polyethylene bags alone. ASBESTOS; CHRYSOTILE; ANALYSTS; CHEMICAL COMPOSITION <324)> Gold, C., Asbestos levels in human lungs., J. Clin. Pathol., 22:507 (1969). Between 1965 and 1969, 620 extracts from lung biopses, lobectomies, pneumonectomies, and postmortem lungs were examined by the potassium hydroxide method. Asbestos was detected in 336 samples; 292 of these were quantitated and contained 0 -13,000,000 asbestos forms per gram of dried lung tissue. The severity of lung disease was related to the asbestos count. Asbestos concentrations in all lung tissue extracts from malignant tumor cases were abnormally high; however, counts from actual tumor tissue were low for pleural and peritoneal mesothelionas and high in bronchial carcinomas. Cores of ferruginous bodies isolated from lungs of 28 urban dwellers not occupationally exposed to asbestos did not show the characteristic electron diffraction pattern given by chrysotile. The absence of this pattern excluded chrysotile as a cansative agent in the formation of the ferruginous bodies. This is a significant finding because chrysotile comprises more than 90 percent of the asbestos used, in the W.S. Impressions gained from the Conference are the following: (1) so-called "asbestos bodies" are not specific indicators of asbestos exposure and have been found after exposure to talc, glass, graphite, and carborundum; (2) a single lung section will show asbestos bodies because of uniform distribution; (3) asbestos accumulates in phagosomes of macrophages after phagocytosis and may escape into the cytoplasm after forcing rupture of these vacuoles; (1) the hemolytic activity of different forms of asbestos is related in a linear fashion to the magnesium:silicon ratio of the fibers; (5) longer fibers are more fibrogenic than shorter fibers; (6) following subcutaneous implantation in animals, asbestos migcrates through the lymphatics to the pleura and the peritoneum where it induces mesotheliomas; (X) quantitative examination of serous fluid for hyalurontc acid is valuable for confirming mesotheliona; (8) mesothelionas are associated with asbestos and occur more often than in the past; (9) a co-carcinogenic relationship exists between sooking and asbestos inhalation. ASBESTOS; ASBESTOS BODIES; ASPRESTOSIS; CANCPR; STANDARDS; MESOTHELIOMA; HUMAN <328> Karacharova, V.N.; Ol'shvang, R.A.; Kogan, F.M., Changes in certain organs after experimental intraperitoneal injection of asbestos-containing dust., Biull. Eksp. Biol. Red., 67: 117-120 (1969) Rats injected intraperitoneally vith 50 mg. of chrysotile, actinolite, tresolite, or brucite dust developed a fibrogenic response in the mesentary as evidenced by the formation of cell nodules consisting of dust macrophages surrounded by collagen fibers. Chrysotile and brucite induced the strongest fibrogenic response. Though some particles miarated to lung tissues and alveolar cells, fibrotic action of the dust was manifested mainly at the injection site. letection of asbestos particles in histologic samples of mesotheliomas requires incineration of the sample, treatment with concentrated RCI, evaporation, washing, filtering, microscopic examination, and electronic microdiffraction analysis. Additional samples must be incinerated and analyzed by x-ray diffraction to detect asbestos forms, such as chrysotile, which partially react with HCI. ASBESTOS; CANCER; MESOTHELIOMA; ANALYSIS <330> Longley, P.O., The many faces of asbestos disease., Med. J. lust., 56-2(21): 1063-1066 (1969) An asbestos body may vary in length from 20 u to more than 200 u; it contains an asbestos fiber coated with a protein gel which is impregnated with ferric compounds. Asbestos bodies generally appear to be innocuous bat can cause pulmonary fibrosis when the coating is disintegrated by some means.

ASBESTOS; LUNG
while the presence of asbestos bodies indicates exposure to asbestos, it does not in itself indicate the presence of asbestosis. Asbestosis development depends on the concentration and duration of exposure to asbestos, T-ray examination is commonly used to detect asbestosis before any symptoms have developed. In some cases, carcinoma has occurred in occupationall exposed workers, even though asbestosis could not be confirmed by x-ray examination. Usually a long time (30-B0 years) elappes between initial asbestos exposure and the appearance of a tumor. Most asbestos-related mesothelionas have occurred after exposure to crocidolite and not to amosite or chrysotile. ASBESTOS; AS8FSTOSIS; ASBESTOS BODIES; MESOTM LIOMA; CANCER; TUMORP OCCUPATIONAL EXPOSURE; CARCIWOMA; X-RAY; DIAGNOSIS (33 1> MacPherson, P.; Davidson, J.K., Correlation between lung asbestos count at necropsy and radiological appearances., Brit. Med. J., 1: 355-357 (1969).
A correlation was made between asbestos counts in lung tissue and evidence of asbestosis on chest x-ray; among 100 cases exasined, radioloqlcal features of asbestosis were observed In 8 of 9 cases where the asbestos count at necropsy exceeded 40. Radiographic abnormalities such as calcified and non-calcified pleural plaques are more likely to be associated with higher asbestos counts.  Med., 26: 302-307 (1969).
An attempt was made to validate the certified cause of death for 301 deceased workers in an asbestos factory by reviewing necropsy reports for 52W of the group and histological material for 28%. Eight additional cases of broncial carcinoma were diagnosed from necropsy and histological reports. Endothelioma or mesothelioma was the certified cause of death in 4 cases, but 15 additional mesothelionas were identified; 5 were in patients whose certified cause of death was carcinoma of the lung or pleura and 10 occudred in patients whose death had been attributed to carcinomatosis with no mention of a primary tumor or to cancer of the gastrointestinal tract. Some degree of asbestosis was found in all but 7 of 67 lung section reviewed. Moderate Cancer, 5:16-158 (1969) No case of mesothelioma has yet been reported from the pathgloqy center at the University of Perugia, Italy, thouqh primary tumors of the lung are seen as frequently as in other comparable departments of pathology. The area is almost free from atmospheric pollution and is not an industrial city. At autopsy, 109 consecutive cases were examined; a low incidence (less than 1l) of asbestos bodies is  Dis., 99(21: 194-204. (19691 Both airway conductance and specific airway conductance were measured in 22 subjects with severe bronchitis, in 10 subjects with suspected mild bronchitis, and in 6 subjects with bronchial asthma. Measurements made using the body plethysnograph were compared for 32 normal individuals and 12 asbestosis patients. High correlations existed between conductance tests, peak flow, and one-second timed vital capacity in obstructive disease. Generally, normal subjects had a greater individual conductance-lunq volumn slope than patients with chronic bronchitis and a smaller slope than patients with asbestosis. BRONCHITIS; ASBESTOSIS; RESPIRATORY DISEASE; VENTLATORY DEFECTS; DIAGNOSIS; HUMAN <338> Pylev, L.N.; Roe, F.J.C.; Warwick, G.P., Plimination of radioactivity after intratracheal instillation of tritiated 3,0-benzopyrene in hamsters., Brit. J. Cancer, 23(11: 103-115 (1969).
Hamsters inlected intratracheally with etther tritium-labelled 3, 4-benzopyrene (18P)y labelled BP and asbestos, or labelled BP and carbon black eliminated,-via the lunqs, 9Q% of the radioactivity during the first 3 weeks after injection. Following this rapid excretion period, both asbestos and carbon black significantly increased the retention of residual radioactivityr More macrophages were recovered from the lungs after administration of BP plus carbon black or BP plus asbestos than after administration of BP alone; but the radioactivity per macrophage vas higher in hamsters treated with BP alone. Radioactivity levels in liver, kidney, blood and urine were similar for all groups. The results indicate that inhalation of insoluble pa.rticulate matter, from cigarette smoke for example, may enhance the carcinogenic effects of inhaled asbestos in humans.
No asbestos was found in the ftimary or secondary tumoral tissue (diffuse, mixed-type mesotheliona of the peritoneum) of an 80 year old man who had worked in a lignite mine for 10 years and in a construction company for 14 years. Asbestos bodies were found only once in 109 autopsy examinations carried out at the Perugia Institute and not found in any of 48 primary lung tumors. The incidence of sesotheliona of the peritoneum was 0.1% of all consecutive autopsy cases for malignant tumors and 1.23% of all primary and secondary tumors of the peritoneum. ASBESTOS; TUMOR; ASBESTOS BODIES; MESOTHELIOMA; HUMAN <3Is0> Sano, T., Relationship between pneumoconiosis and lung cancer., J. Sci. Labor, 45 (7): 383-396 (1969).
Pneumoconiosis cases associated with cancer in Japan include asbestosis, silicosis, pyropyllite pneumoconiosis, alumina lung, welder's lung and activated carbon lung. In asbestosis patients, cancers may arise from abnormal tissue proliferation (byperplasta, squanous cell metaplasia) on the bronchiolar or alveolar wall due to asbestos inhalation and chronic bronchiolitis. Since tissue damaqe or change may lead to lung cancer, steps should be taken to prevent infection in pneumocon iosis cases. Solomon, A., The radiology of asbestosis., S. Afr. Med. J., 43(27i: 847-851 (1969). Pleural effusions, non-specific pleural reaction, accentuation of. the fissures, lamellar pleural thickening and non-calcified pleural plaques are significant diagnostic changes in patients with a fiistory of asbestos exposur. Cosbined pleural and parenchymal radiological lesions are comson signs of asbestosis but generally are rare in uncomplicated pneumiconioses. Massive fibrosis is common as a basal lesion in asbestosts and unusual in pneuaoconioses associated with qoldand coalmining. Padioloqical chanqes relate directly tc the degree of fibrosis in the lung but do not always correlate with the histological changes.
To more fully understand the biologic effects and structure-activity relationships of asbestiform minerals, the experimental biological evidence must be related to the variations in physical andt chemical properties of each individual asbestos variety. This review discusses the occurrence, crystal structure, chemical composition, surface characteristics, chemical characteristics, synthesis, physical properties, identification, and sources of the various asbestiform minerals. Since 1965 asbestos has been implicated as a cause of mesothelioma in humans. Tt is not known if asbestos is the actual etiologic agent of tumor formationthe interaction of asbestos with associated trace-metals or with polycyclic aromatic hydrocarbons may be essential to initiate mesotheliona development. The degree of asbestos exposure necessary to produce tumors in humans Is unknown.
In-hausters receiving intratracheal doses of soft chrysotile (1 mg), harsh chrysotile !1.1 mg) *and amosite (2.5 mg/month for 10 months), the formation of asbestos bodies was similar for all asbestos types. The lung tissue of all animals shoved marked increase of intraalveolar cells comprisedmainly of alveolar macrophages. Uncoated fibers occurred in alveolar spaces, within alveolar septa, and in the cytoplasm of phagocytic cells.
The fibers vere phagocytosed by macrophages and incorporated into phaqosomes. Hemosiderin granuies accumulated in the cytoplasm, transferred into phagosomes and surrounded the fibers in a loosely packed arrangement to form an 'immature body. The body matured with the accumul&tjon of ttghtly packeed micelles vithin an enclosed membrane. Asbestos body formation appears to be A conttnuous process, with uncoated fibers beinq converted to bodies months or years after asbestos inhalation. Folloving the intratrachial administration of 1 mg soft chrysotile to male hamsters, asbestos bodies formed in the cytoplasm of alveolar macrophages, alveolar epithelial cells, and septum cells in the lung. The process involved the phagocytosis and incorporation of short fiber fragments into the cell cytoplasm; the appearance of hemosiderin granules in the cell cytoplasm; intracellular transport of iron mecelles from the hemosiderin into the phagocytic cells;.and progressive accretion of the iron micelles around the fiber. The resultinq asbestos body consisted of the central asbestos fiber, the peripheral coat of Iron, and the surrounding me.br4ne of the phagosome. A comparative study of mucociliary function among S normal subjects, 6 vith chronic obstructive airway disease, and S with asbestosis shoved no significant difference In the clearance rate of inhaled plastic particles (Su) from the lungs. Clearance during this phase was greatest in subjects having obstructive disease because most of the dust was deposited higher in the bronchial tree with less penetration below the ciliated airways than in normal subjects. Chronic tobacco smoking had no adverse effect on ciliary function. Viqliani, E.C., Asbestos exposure and its results in Italy., fled. Lavoro, 60(s)-: 325-330 (1969).
Of 586 persons compensated for asbestosts in Italy from 1964-196s, the majority (500) worked in one of the following: the asbestos and refractory material trade, the dockyard and' shipbuilding trade, or the textiles and friction material trade. Categorizing the causes of death for' 307 persono compensated'for asbestosis between 1955-1Q69 revealed asbestosis (31.6%), malignancies (22W), tuberculosis (81), or other' causes (38.k1). 'In a group of 232 chrjsotile mine workers who had claimed compensatioh, pleural plaques were found in 3.8W.. Lung cancer caused 3W of the 97 reported deaths, and no mesotheliomds were found. No siqnificant aifferences In the incidence of lung tumors were observed between compensated and non-compensated workers. Wagner, J.C.; l3erry, G., Mesothelionas in rats following inoculation with asbestos., Brit. J. Cancer, 23(31:1567Cancer, 23(31: -v81 (1969. wistar specific pathogee-free and Standard rats were injected intrapleurally with 20 mg of amosite, crocidolite, or chrysotile. more than-50% of the animals given chrysotile or crocidolite' developed pieural mesotheliomas. Amosite produced fewer mesotheliomas and exhibited a longer initial latent period between inoculation and tumor develOpment. utopsied in Melbourne, Australia. The incidence of asbestos bodies was age related; reachipg 50' in the age group ranging from 51 to 80. The equal sex incidence suggests that asbestos exposure resulted from general ato6spheric contpmination rather than occupational exposure. The hiqhest 'asbestos counts were fomnd in one case of pleural mesotheliona and in one case of fibrous pleural plaques. Asbestos is a serious health hafxard to those persons occupationally exposed, and to a lesser extent the general public. Diseases usually associated with asbestos are lung cancer, mesotheltona, and asbestosis. when diagnosing theAe diseases, the carcinogenic potential of asbestos contaminants cannot be excluded; positive Identification of asbestos fibers should be made before repcrting asbestos bodies in cases of mesothelioma and asbestosis. The question to be answered is whether lung cancer is a complication of 8sbestosis or develops in the' absence of this condition. Progress has been made in reducing asbestos exposure levels but there is no room for complacency. Universal agreement must be reached on clinical, physiological, and radiological criteria for diagnosing asbestosis. These authors, with the cooperation of the Asbestos Workers' Union and insulation contractors, are studying environmental exposures and thqt health of asbestos insulation workers in the, estern United States. Surveys have been made in a number of work situations. This report summarizes preliminary a environmental findings on materials used, methods of application, and dust counts for various components of the insulator's jobprefabricatign, application, finishinq, mixinq, and removal of insulation. The study emphasizes exposures to asbestos-containing materialsfiber glass, cork, plastics, and adhesives. The onset of diffuse mesotheliona is usually insidious, as evident in a case report of an asbestos sheet-stacker with asbestosis. Earlier examinations of the 54-year-old male revealed slight reduction of vital capacity and diminished diffusinq capacity. Seven years later the patient was rehospitalized because of paroxysmal cough accompanied by severe pain in the right chest. Dyspnea progrpssed rapidly as sero-sanquinous fluid accumulated. The admission roentgenjogram showed a riqht-sided massive pleural effusion whereas the left lung was more diffusely infiltrated and appeared honeycombed in many areas. Un involved areas showed signs of asbestosis. The disease had its usual rapidly fatal coarse. The patholoqical findings at autopsy are presented.  331-350 (1967-1968) various techniques are evaluated for identifying fibrous microscopic particulates in tissue sections.
Standard techniques for mineral separation from tissue are qenerally unsuitable for asbestos. Harsh chemical and physical analyses give less satisfactory results than other methods. Combinations of electron diffraction, transmission microscopy, and microprobe chemical analysis provide information concerning morphology, chemistry, and structure of the particle exaCined. ASBESTOS-, ANALYSIS; CHEMICAL COMPOSITION <359> Biles, B.; Emerson, T.R., Examination of fibres in beer., Nature, 219 (51499: 93-94 (1968) Asbestos pads frequently are usd for filtratton in the bmveraqe industry. A method has been devised by which water and formulated drinks may be scanned for asbest6s fibers by electron microscopic examination.
Three and A hours after inhalation exposure, anthophyllite fibers were observed in the terminal bronchioles and alveoli of guinea pigs. These fibers are phaqocytosed by the alveolar macrophaqes. The ftrst pathological effects observed were hemorrhage from alveolar capillaries, hemolysis of extrawascular red cells, and formatipn of iron-contatning granules. Macrophages contained hemosiaerin qranules together with a solubiltzea iron-containing product (possibly ferritin) diffusing throughout the cytoplasm. Asbestos bodies form when ferretin adsorbs onto asbestos fibers after they are ingested by the macrophages; only I fiber--usually the longest--becomes coated in each macrophage. After 4 weeks the coating thickens and the cell shrinks onto this structure. After ten weeks, asbestos bodies become finely beaded and may fragment. Thirty years after initial exposure to asbestos, an epidermolA bronchial carinoma was detected in a woman who did not smoke and who had been employed as an asbestos worker for 13 years. At autopsy, histological examination revealed asbestos bodies (previously not found in the sputum) in the intra-alveolar fibers of the lungs. Systematic bronchial endoscopy is recommended for all individuals exposed to asbestos for 20 years. ASBESTOS; ASBRSTOS BODIES; CANCER; CARCtIOMA; DIAGNOSIS; LUNG; OCCUPATIONAL EXPOSURE; HURAN <362> DeTreville, R.T.P.; Gross, P.; Davis, J.M.G., Asbestos bodies and their bioeffects., J. Amer. Ped. Assoc., 203(13): 1142Assoc., 203(13): -1143Assoc., 203(13): (1968. A letter to the editor details briefly a chronological review of asbestos bodies from discovery, through a period of little clinical significance, to the present position as one of the greatest industrial medical problems. Accurate 7dentification of "troe" asbestos bodies continues to be a ma lor probleim.  Fennessy, J.J., Bronchial brushing and transbronchial forceps biopsy in the diagnosis of pulmonary lesions., Dis. Chest, 53(4): 377-389 (1968) P technique of transbronchial biopsy, using instru ents inserted thrbugh a catheter under fluoroscopic control, is employed when routine techniques fail to establish the diagnosis of a pulsonary lesion. Brushes with nylon bristle are used if there is some distance between the tip of the catheter and the lesion, whereas brushes with steel bristle are used when the disease process is diffuse. A positive cytologic or pathologic diagnosis was established in the majority of cases (644w) with primary pulmonary tumors, but the method has proved less accurate in diagnosing metastatic carcinoma and pulmonary tumors. More viqorous use of the biopsy forceps will improve the diagnostic yield of this technique. retrospective examination of a ten-year-autopsy material., Acta Pathol. Microbiol. Scand., 72(2): 17 '-191 (1968) During one decade (1057 through 1966), 3; cases of mesothelioma were found in 12,763 autopsies; at the same time 34 mesotheliona cases were re-examined for the presence of asbestos bodies in the lungs. Asbestos bodies were found in 18 cases in the mesothelioma group and in 12 cases in the control population (34 autopsy cases). For a correlation between the presence of asbestos bodies and mesothelioma to be proven, asbestos bodies must be abundantly present in the cases of mesothelioma. ASBESTOS; ASBESTOS BODITS; ASBESTOSIS; MESOTHELIONA; HUMAN <367> Harries, P.G., Asbestos hazards in naval dockyards., Ann. Occup. Hyg., 11: 135-145 (1968). Asbestos materials are used extensively in shipbuilding and ship repairing. Although numerous preventive methods have been instituted, problems still exist as to occupational exposure, compensation, and improved methods of diagnosing asbestos-associated diseases. Public interest has been aroused by the direct association between asbestos and pulmonary fibrosits, various malignancies, and more recently, the demonstration of asbestos or mineral-fiber bodies in populations having no industrial exposure. Clinical and radiological aspects are discussed along vith two major criteria for the diagnosis of asbestosis: history of the inhalation of significant amounts of asbestos dust over an extended period of time and a consistent 'chest roentgenogram. Tnd. Med., 25(4): 193-303 (1968).
The causes of death for persons working in an asbestos factory were examined for a 50 year period . The beginninq date for workers employed under improved working conditions was January 1, 1Q33, after the introduction of the Asbestos Industry Regulations in 1931. Death rates have been recorded for 256 men employed for at least 20 years and for 538 men and 220 women emploved for at least 10 years since 1933. Results show a substantially increased mortality for men exposed 10 or more years before 1933 (48 deaths from all causes comnared to 17.1 expected). Men employed before lQ33, but for less than 10 years, showed an increased mortality from lung cancer (E deaths against 2.6 expected), but no significant increase from other causes. Men and women who were exposed since January 1933 had a mortality comparable to the national average. Statistical analysis of the trends indicated a significant reduction of the occupational hazards of asbestos since 1Q32 (at least with respect to bronchial carcinoma). chrysotile was the predominate asbestos type used in the factory, but small amounts of crocidolite also were processed. ASBESTOS; CHRYSOTILE; CROCIDLIT!; OCCUPATIONAL EXPOSURE; HUMAN; CANCER; CANCER MORTALITY <370> Lynch, J.R., Brake lining decomposition products., J. Air Pollut. Contr. Assoc., 18(11 : 824-826 (1968). Only a small proportion of the asbestos worn from brake linings is released into the atmosphere as free fibers. The remainder is converted into a different nonfibrous mineral resulting from thermal metamorphosis of asbestos. A significant release of fibers occurred only under conditions extreme enough to produce brake failure. Slight inhalation of asbestos, often 20 or 30 years previously, has been associated with benign pleural plaques or malignant diffuse mesothelio*a. Direct relationship between asbestos exposure and pleural plaques remains obscure, however. As yet, only an association has been demonstrated, not an obvious causal relationship. Other still unidentified pathogenetic factors have to be considered, either as a contributary or sole cause of these lesions. Further, occurrence of bilateral calcific plaques can not be considered prima facie evidence for asbestos-pn eumoconiosis. Radioloqical examination showed lung fibrosis, pleural plaques, pleural calcification, and pleural thickening that suggested mesothelioma. Necropsies at death confirmed pleural mesotheliona and the presence of asbestos bodies in both patients; the neoplasms differed histologically. Asbestos exposure in both was minimal, neither had significant lung fibrosis, and both patients had smoked tobacco for 29 to 40 years. These cases are among the first to be reported in Australian Chest, 53(1 : 89-92 (1968) When introduced into the pleural cavity of dogs, a penicillin-asbestos paste effectively destroys the mesothelial lininq by abrasion. The mesothelial layer is completely replaced by a thick layer of vascular granulomatous tissue which obliterates the pleural cavity. The asbestos powder blankets the pleural surface, continues the irritation initiated by the penicillin crystals, and leads to the production of granulonata and dense adhesions. Asbestosis may occur with or without the usual symptoms. Six cases are presented which confirm nodular lesions in radiographs of patients with asbestosis. wecause complications of asbestosis can be fatal, asbestosis should be considered in the differential diagnosis of patients with nodular lung lesions who have been exposed to asbestos. Complications of asbestosis include pulmonary fibrosis, pulmonary insufficiency, bronchogenic carcinoma, malignant mesothelioma, and abdominal tumors. MESOTHELIOMA; TUMnR <375> Noro, L., Occupattonal and "non-occupational" asbestosis in Finland., Amer. Znd. Hyg. Assoc. J., 29 (3): 195-201 (1968) Asbestos, like hundreds of other agents, is a dangerous material that may jeopardize workers' health if not properly controlled; the incidence of asbestosis in Finnish asbestos workers can be reduced by modern industrial hygiene. Anthophyllite comprises Finland's asbestos reserves. Too little is known about the danger of non-occupational exposure to the general population. The mortality rate from cancer and other malignancies in the immediate asbestos area is equal to other rural areas of the country, although in asbestos workers the f requency of lung cancer might be somewhat higher. There is enough evidence to kindle interest in this health problem; many questions are still unanswered. when incubated with guinea pig macrophages, Balangero chrysotile and South African crocidolite dusts were cytotoxic. Results showed a decreased production of lactic acid, kinetic loss of fluorcchromasia, and a rapid release of lactate dehydrogenase (LDR); release of lysosomal enzyme acid phosphate (RPH) was only slightly greater than in the controls. The fibrous fraction of the dusts was more toxic than the particulate fraction. Pretreatment of chrysottle fibers with ethylenediaminetetraacetic acid and polyvinylpyrrolidone nitrate did not modify the release of LDO or APR, thus suggesting that the cytotoxic action resides in the physical properties of the dusts rather than the chemical composition. Asbestos bodies were reported in basal lung smears from 26 out of 100 consecutive autopsies in Jerusalem. The clinical pathology study revealed that 29.1% of the sales and 22.2% of the females showed a presence of asbestos bodies. This incidence of asbestosis as well as pleural and peritoneal mesotheliona can be expected to increase with the increasing use of asbestos, particularly in urban settinqs. Ashkenagi Jews had a statistically higher incidence of asbestos bodies than other Jews. Asbestos exposure was not due to occupational exposure. Differentiation between true asbestos bodies and pseudoasbestos bodies is descrtbed. Med. 1., 42 (14): 325-326 (19681. Emphasis has shifted from occupational asbestosis to merely casual asbestos exposure as the cause of malignancy. Asbestos may be a true carcinogen or a co-carcinogen giving rise to an increased incidence of tumors. Demonstration of asbestos bodies in large numbers of urban dwellers lends support for the condemnation of asbestos. inspection of causal concept reveals potential problems: Cigarette smokting and atmospheric pollutants other than asbestos induce bronchoqenic carcinoma; mesotheliona may not exist as a distinct entity. The assoctation between asbestos and neoplasia needs reevaluation to halt the risk of assumption and to carefully reappraise the situation by all available methods. Recently there has been an increasing risk of jlung cancer in persons occupationally exposed to asbestos. The latent period for most lung cancers is *ell in excess of 25 years. The use of effective dust controls in work areas has delayed death from asbestosis and increased the time during which lung cancer may develop; the latest figures indicate that more than ;09 of persons with asbestosis will develop luno cancer. Since 196O, pleural and peritoneal mesothelioma has been associated vith asbestos exposure; in many patients who develop this rare tumor, the extent of exposure is insufficient to cause ashestosis. ASBESTOS; ASBESTOSTS; CANCER; MESOTHELIOMA; HUMAN; OCCUPATIONAL EXPOSURE; LUNG <380> Roe, F.J.C., Experimental asbestos carcinogenesis., Food Cosmet. Toxicol., 6,(5): 566-568 (1968). Some months after six subcutaneous injections of asbestos fibers totaling 60 mq of crocidolite, amosite, extracted amosite or chrysotile, marked changes were observed in the mescthelial and subsesothelial tissues of CBA mice. These changes consisted of the deposition of asbestos fibers, thickening and edema, inflammatory infiltration, and cellular proliferation. In ten animals changes were regarded as malignant mesotheliomas (four peritoneal,. four pleural, and two involving both peritoneum and pleurae). The incidence of mesothelial changes was lower in response to extracted amosite and crocidolite than to crude fibers. AMOSITE; CHPYSOTILE; CROCTDOLITE; MESOTHELIOMA; FOUSE <381> Royall, N.J., The health of the public and asbestos usaqe., J. Poy. Inst. Public Health, 31:126-146 (1968) The relation of increasing asbestos use to public health is emphasized by describing: history, types, properties, production, uses, health risks, nesotheliona, diagnosis, pathology, histology, and latency period. Non-occupational mesothelioma cases due to both domestic and environmental exposure in London (415) and South Africa are reviewed. Crocidolite appears to be the most dangerous asbestos. ACTINOLITE; AMOSITE; AMPHIBOLE; ANTROPHYLLITE; ASBESTOS; ASBESTOS BODJES; ASBESTOS MINING; CHRYSOTILE; CROCIDOLITE; HUMAN; MESOTHLTIOMA; NOW-OCCUPATIONAL EXPOSURE; OCCUPATIONAL EXPOSURE <382> Rusby, M., Pleural manifestations following the inhalation of asbestos in relation to malignant change., J. Roy. Way. Med. Serv., r54(2): 142-148 (1968) Thickening of the pleura with horn-like plaques has been a long recognized feature of asbestosts, but only recently has holly-leaf calcification been associated with asbestos inhalation. It is possible that the less concentrated exposure encountered from environmental or domestic sources, as opposed to industrial exposure, may determine whether a person gets pleural manifestations rather ,than pulmonary fibrosis. Years pass for pleural calcification to manifest overtly; x-ray visualization is possible In  (2): 106-110 (1968). The risk of death by bronchogenic carcinoma in asbestos insulation workers is about 7 or 8 times higher than expected. over a 52-uonth period, 370 vorkmen were observed and followed medically -283 were regular cigarette smokers, 87 were not.
Pronchogenic carcinoma claimed the lives of 214 smokers--only 3 deaths from this cause were expected; no non-smokers died from this disease. Calculated results indicate that in asbestos workers who smoke, the risk of dying from bronchogenic carcinoma is about 92 times greater than for men who neither smoke cigarettes nor work with asbestos. Asbestos exposure should be minimized, asbestos workers who smoke should stop imeidately, and those not smoking should never start. The prevalence of asbestos associated abnormalities and their relation to exposure vere studied by means of a one-in-ten survey of 15,000 naval dockyard worlkers. of the 911 examined, 3% had experienced continuous occupational exposure whereas nearly half the remainder had been exposed intermittently. Pleural fibrosis was more prevalent in continuously exposed workers (281) than those with least exposure (1.91). Pulmonary fibrosis occurred mostly in laggers and sprayers who had been continuously exposed for 15 to 20 years. In the last 3 years ten cases of pleural mesothelioma have occurred; a large number of workers appear to be potentially at risk. Peritoneal sesotheliona often is indistingutshable from carcinonatosis peritonei because of the similarity in tumor growth. One must establish an accurate diagnosis to assess the risk associated with asbestos exposure. Two cases of peritoneal mesotheliona are presented along with a reviev of 10 clinical cases. One case involved a 54-year-old man who had applied asbestos linings to pipes for more than 15 years; the other man, 50 years old and the brother of case 1, insulated pipes and boilers for 36 years. of the 21 cases of mesotheliomas reported in the Province of Tealand in the Netherlands during a three year period, 17 cases occurred in former employees of the same shipyard. Only slight exposure to asbestos occurred to these workers but nearly all had been exposed to high concentrations of iron oxide. Autopsy examinations of lung tissue revealed objects similar to asbestos bodies but no trace of asbestosis. Electron diffraction studies showed that the cores contained asbestos of the amphibole type, thus proving that they were not pseudomorphic. Simultaneous exposure to low concentrations of asbestos and high concentrations of iron oxide raises suspicion that iron oxide might be an important cofactor in the genesis of mesothelioma in shipyard workers. Ferruqinous bodies with transparent or invisible central filaments were found in lung tissue from 97 of 100 random autopsies of city dwellers who had not been occupationally exposed to dust particles. Mo apparent association vas evident between malignancies (32 cases) and the relative abundance of ferruqinous bodies; rarely was pulmonary fibrosis or neoplasm associated vith these bodies. Althongh two cases of primary lung cancer were diagnosed in sen no mesothelioma or asbestosis was found.
Epidemiologically, the significance of these findings must await identification of the central core of the ferruginous bodies. Vigliani, E.C., The fibrogenic response to asbestos., Med. Lavoro,,: 401-410 (1968) A half century of experience in clinical and pathological observations of human ashestosis indicates that all types of asbestos are fibrogenic if inhaled in sufficient amounts over a long period of time. The question that remains unanswered is vhether one type of asbestos is more fibrogenic than others. The malor fibrogenic pathways involve the direct stimulation of fibroblasts, conversion of macrophages and giant cells into fibroblasts, release of a fibrogenic factor from macrophages, and appearance of giant cells which release a fibrogenic factor. Three theories hypothesize the fibrotic action of asbestos: Mechanical Theoryirritation and microwounds are produced by fibers; rhemical Theoryfibers dissolve, liberating fibrogenic compounds; and Surface Theorythe surface and shape of asbestos lead to fibrogenesis. AMOSITE; ANTHOPHYLLITE; ASBESTOS; CHRYSOTTLE; CROCITOLITE; FIBROGENIC TISSUE RESPONSE; HUMAN <392> Viqliani, E.C.; Ghezzi, I.; Maranzana, P.; Pernis, B., Epidemiological study of asbestos workers in Northern Italy., Med. Lavoro, 59(8-9): 481-485 (1968). From April 1943to December 1967 persons receiving disability compensation for asbestosis died in Italy (Piedmont, Lombardy, Liquria); 32 worked in asbeotos mining, 161 in manufacturing, 60 in asbestos-cesent production, and 35 in insulation works. Of these deaths, 28 (101) died from lung tumor or mesotheliona of the pleura, 36 from neoplasia at other sites, 93 from complicated cardio-respiratory disease, 22 from tuberculosis, 81 from other causes, and 28 from undetermined causes. The incidence of lung cancer isong male asbestos workers was twice as high as that of the general population in Rilan and Turin, and eigbt times higher than that of stlicotic patients who died in the same period. miners exposed only to chrysotile had the lowest incidence of lung tumors. Bilateral pleural calcifications were radiologically detected in two men. Both, aged 61 and 56, were asbestos workers. Routine histology was inconclusive; mineralology with polarizing microscopy of visceral pleura and bronchial wall tissue specimens revealed tremolite asbestos and crystals. Pecause asbestos bodies in dust are nonspecific and variable, testing methodology as described is both precise and specific for asbestos body detection in animal tissues.  Environ. Health, 15: 285-289 (1967).
The world proauction of asbestos in 1965 was more than 3.5 million tons (90% consists of chrysotile). The increasing use and indespensibility of asbestos requires the reexamination of dust standards. The demonstration of ferruginous bodies in 25-50 of many urban populations indicates an urgent need to positively identify the causative fibers. Cofactors such as cigarette smoke, metal contaminants and oils in asbestos may act synergistically with asbestos in producing malignancies of the pleura and peritoneum. Asbestos textile workers in the past were exposed to airborne dust containing signiftcant amounts of nickel, chromium, manganese and other metals, due to poor dust controls in the textile plants. In addition to the naturally occurring metal content of asbestos ore and fibers, the abrasive action of asbestos on metal equipment used for milling and processing the fibers contributes metals to the resultant asbestos product. Further study should determine the etiologic role of trace metals in pulmonary disease related to asbestos exposure. Small sections of adult guinea pig lung were injected with chrysotile dust and maintained in organ culture for 10 to 14 days. Dust was incorporated in phagosomes by most of the lung macrophages within two hours; dust was not found in any other cells. Usually, the dust was liberated into the macrophage cytoplasm due to phagosome rupture, or walled up in dense residual bodies.
Asbestos industries have been negligent in accepting the responsibility for hazardous working conditions, excessive production of asbestos products for public use, and indescriminant pollution of the environment with asbestos wastes. Only mild, brief, asbestos exposure (occupational or non-occupational) is necessary to produce asbestosis and pleural mosothelioma. The occurrence of asbestosis in wild baboons, donkeys and rats near mining areas in South Africa supports evidence that asbestos pollution may be contributing to the declining quality of urban health near asbestos mines and factories. Thirty-one cases of asbestosis and asbestosts with silicosis have been studied in a hospital in Perth, Australia over a five year period. Twenty-eight of these worked at an asbestos mine-mill and 3 at an asbestos cement works. History of exposure, pulmonary function tests and radiological changes were used to diagnose asbestosis. Exposure for 1 1/2 to 12 Tears at the mine was sufficient to produce disease and death in 7 cases, while at the cement works a period of 17 to 27 years was necessary to produce disability and one death. Pulmonary infection seems to accelerate the progress of the disease. Once radiologically evident, the disease is well-advanced. Radiological exams can be of diagnostic benefit but are very difficult to interpret even by experts. Changes in vital capacity may be more reliable since they may occur before radiological changes. Steroids are to be avoided in treatment of asbestosts.  Radiology, 89 (2): 224-229 (1967) In 56 of 187 asbestos workers studied, pulmonary roentgenoloqic changes were evident. The most common finding was pleural thickening --frequently associated with parenchymal fibrosis. Ventilatory function was measured in 41 male workers engaged in the manufacture of asbestos. The twelve workers who were left in the 3 1/2 tear interval between surveys were found to have a significanly lower vital capacity and a significantly higher ventilatory requirement during exercise than those who remained in this work, probably because, on the average, they were 9 years older and had 6 more years exposure in tte asbestos industry. Compared to controls, the asbestos workers demonstrated a greater decrease in forced respiratory volume than expected with greater changes in vital capacity and ventilatory requirement. Functional abnormality is consistent with but not predictive of asbestosis. ASBESTOS; OCCUPATIONAL EXPOSURE; RUMAN; VENTILATORY DEFECTS <41041> Ghezzi, I.; Molteni, G.; Puccetti, U., Asbestos bodies in the lungs of inhabitants of Milan., Med.

ASBESTOS
Lavoro, 58 (3): 223-227 (1967) Asbestos bodies were found in 51 of 100 sublects (6(1 men and 36 womeh) studied at autopsy. Of the 51 positive cases, 144 were women. Asbestos bodies were found more frequently in the older people and in those demonstrating pulmonary edema. A sliqht pulsonary fibrosis was found in one case but no asbestosis was demonstrated clearly. No pleural plaques or thickenings were found in the K5 subjects examined for these effects, althouqh ashestos bodies were found in some. The age range of this non-occupationally erposed group was from 25 to 83 Ruman ovarian cancer morphologically resembles mesotbelionatas, and clinically has been reported in association with asbestosis. To determine the effects of asbestcs on ovaries, tremolite (2.5% in tap water) was injected intraperitoneally into Swiss mice (0.1 cc), hamsters (0.2 cc), guinea pigs (0.5 cc) and D)utch rabbits (1.0 cc). The injection was repeated once a week from week 10 through 18 of the experiment. wo abnormalities were found in the hamsters, mice, or controls; in these species a peritoneum layer protects the ovaries from contact with asbestos. At weeks 7 and 17, 2 of 10 rabbits and 2 of 16 quinea pigs had developed ovarian epithelial abnormalities which were similar to those seen in early ovarian lesions in humans. ASBESTOS; MESOTHELIOMA; ASBESTOSIS; GUINEA PIG; RABBIT; MOUSE; TREMOLITE; CANCER, HUMAN; OVARY <1106> Gross, P.; Cralley, L.J.; DeTreville, P.T.P., "asbestos" bodies: their nonspecificity., Amer.
"Asbestos" bodies formed in the lungs of hamsters injected intratracheally vith filamentous respirable particles of aluminum silicate. These bodies develop in the lung as a pulmonary response to foreign substances and, unless identtfied unequivically, some confusion might exist by calling them asbestos bodies. The term "ferruginous body" is suggested for the iron containing body which forms in response to nonasbestos dust in the lungs. ASBESTOS BODIES; HAMSTEP; LUNG; FERRUGINOUS BODIES <1 07> Gross, P.; DeTreville, R.T.P., Experimental asbestosts: studies on the progressiveness of the pulmonary fibrosis caused by chrysotile dust., Arch. Envlron. Realth, 15: F38-649 (1967).
Guinea pigs, rats, and hamsters were exposed to various burdens of chrysotile dust by inhalation and by intratracheal injection. Asbestosis in rats is nonprogressive: asbestotic lesions heal in the absence of asbestos bodies and in the presence of chrysotile fibers which become entrapped in scar tissue. There is a considerable reduction in the amount of dust in lung sections one year after exposure compared to directly after exposure. Tn hamsters, lesions are progressive and do not heal; demonstrable amounts of asbestos dust in lung sections are diffusely distributed. In guinea pigs, the early asbestotic lesion is similar to that of rats, but further study is needed.
One hundred thirty-one rats vere exposed to finely milled chrysotile at air concentrations of 42 to 146 mq/cubic meter for 6 hrs. a day, 5 days a week, for a maximum of 62 weeks. Half of the rats also were exposed to sodium hydroxide (NaOH) to reduce lung clearance, thereby maximiizing dust retention and pethogenicity. Primary malignant lung tumors developed in 31% of those surviving 16 months or more; tumor incidence in NaOH-treated rats was 486 --twice as high as in rats treated only with asbestos. Cancer induction also may involve trace metals (nickel, chromium, cobalt)  Radioactive chrysotile fibers, suspended in physiologic saline, were injected intrapleurally (3 mq) in two 3-month-old rats. Small amounts of the radionucltdes (scandium, chromium, iron, and cobalt) were found in the feces and in all tissues. However at 8 and 50 days after treatment, 906 of the radioactivity remained in the pleural cavity and lungs, indicating that translocation of asbestos fibers from the lung area is a slow process. CHPYSOTITLP TISSUE DISTRIBUTION; RAT; tLNG; PLEURA <( 11> Jagatic, J.; Rubnitz, M.E.; Godwin, N.C.; Weiskopf, R.N ., Tissue response to intraperitoneal asbestos with preliminary report of acute toxicity of heat-treated asbestos in mice., Environ. Res., 1: 217-230 (1967). mice inlected intraperitoneally with chrysotile asbestos demonstrated an extensive fibrous tissue reaction which was proliferative, granulomatous, and invasive. Intraperitoneal injection of asbestos that was subjected to heat (1000 C for 3 hours) produced acute toxic reactions; death occurred in 26 of 90 mice within 36 hours, and 4 more died after 48 hours. Survivors recovered well and were alive 7 months later.  Ind. Med., 24: 232-239 (1967).
Examination of 12 workers who experienced minimal asbestos exposure included: occupational history; syptcmology; clinical examination; and physiclogical tests (spirometry). Out of 10 transformer workers who used asbestos, two showed minor radiological and physiological pulmonary changes correlated with early asbestosis. Two insulation workers who engaged in millingq and grindinq asbestos sheet (5 and 23 years exposure) showed similar but more progressive signs and symtoms due to higher asbestos exposure levels. Retrospective histories were recorded for 12 cases of mesothelioma to correlate the malady with exposure to asbestos. Ten patients worked in ashestos plants, A lived or worked close to asbestos plants, 3 were family members of asbestos workers. Asbestos exposure was affirmed in an additional 10 cases, and the remaininq 11 had no history of asbestos exposure. Newhouse, M.L., The medical risks of exposure to asbestos., Practitioner, 199: 285-293 (1967).
Asbestos is the generic name for varieties of fibrous mineral silicate consisting mainly of crocidolite, amosite, chrysotile, and anthophyllite.
The resistance of asbestos to heat, friction, and acid combined with its tensile strength and flexibility have made it useful in more than 1000 applications. World consumption is more than 3 million tons per year; chrysotile, a magnesium silicate, comprises 931 of the output. Approximately 2/3 of the asbestos produced is used in cement products. High incidences of health disorders such as asbestosis, bronchial carcinoma, mesothelioma of the pleura or peritoneum, and gastrointestinal tumors occur among exposed workers, particulary in asbestos mininq, millinq, textile, cement, insulation and lagging occupations. However, occupational hazards can be minimized by engineering methods of dust control, continual monitorinq of dust -concentrations in worlk areas, and strict codes of practice for the workers. Domestic exposure to dust on the clothes of relatives in asbestos occupations, and residential exposure in areas near factories and mines also cause asbestos related diseases.  (1967) Both occupational and non-occupational asbestos exposure are becoming increasingly more hazardous as multiple adverse bioloqical effects are being recoqnized. Piseases and biological effects recognized are: bronchiectasis, asbestosts, chronic pneumonitis, emphysema, chrontc pleuritis, pleural plaques, corpulmonale, carcinoma of the lunq, diffuse mesothelial tumors of the pleura and peritoneum, castrointestinal tumors and possibly, ,3varian tumors. The latent period between last asbestos exposure and disease signs and symptoms may extend 30 to 40 years. Four selected case studies demonstrate asbestosis with pulmonary emphysema and corpulmonale, asbestosis with lung cancer, mesothelioma, and rectal carcinoma in workers exposed to asbestos. ASBESTOS; ASBESTOSIS; CANCER; CAPCTINOA; ENVIRONNMENTAL CONTAMtIATION; HUMAN; MESOTHELIOMA; OCCUPATIONAL EXPOSURr; GASTROINT'eSTITAL <4117> Pennarola, P.; Eliseo, V., Cytologic morphology of the sputum in asbestosis of the lung., Folia Medica, 60 (1): 1-12 (19}7).
Sputum from 30 asbestosis patients was examined using the Papanicolau and Sirtori techniques.
The incidence of asbestos bodies in 100 consecutive adult necropsies was investigated in Glasgow, Scotland, near an industrial shipbuildinq area. Asbestos bodies were found in 23 of 62 males, and none of 38 females. Among cases showinq asbestos bodies, 11 had hyaline pleural plaques, 1ihad ashestosis and 3 bad bronchial carcinomas. The occupational histories were not known. Hammond, E.C., Asbestosis and neoplasia., Amer. J. med., 42(4) : 487-496 (1967) This editorial broadly outlines some of the present and future problems of an industrialized society which heavily depends on asbestos; emphasized is the increased probability of asbestos becosing a greater hazard. Because of the long latent period between initial asbestos exposure and related disease manifestation (36 yrs.) it is difficult to assess the significance of small quantities inhaled inasbestos contaminated air; the effects of current environmental releases of asbestos may not manifest in the general population until the 1990s. The incidence of asbestos-induced lunq cancer may equal cigarette-induced cancer in the next fey decades.  Health, 11: 300-308 (1967).
Talcosts, a pneumocontosis found in some talc miners and in workers in related industries, is probably caused by tremolite present in the talc. Of the two types of talc deposits most economically important, the type formed from carbonate rocks and containing talc, tremolite and often anthophyllite presents the greater industrial hazard. PNEIIUOCONTOSIS; TREMOLITE; OCCUPATIONAL EXPOSURE: ANTROPHYLLITE; FIBROSIS Environmental Health Perspectives <4(22> Zolov, C.;Pouriltov, T.;Babadjov, L., Pleural asbestosis in agricultural workers., Environ. Res., 1: 287-292 (1967).
In rural Bulgaria, fluorographic examination of 3,325 people living within 10 km of an asbestos mine revealed 154 cases of pleural asbestosis; 132 had no occupational contact with asbestos (86 men and 46 women). The majority (71.6W) were agricultural workers over 50 years of age, working in tobacco production. The cultitvation of tobacco in stony qround is thought to be a contributinq factor since the soil contains asbestos minerals.
Amino acid analysis of asbestos bodies shows that they are not asbestos fibers coated vith collagen deposited by fibroblasts: (1) hydroproline, qlycine, leucine and phenylalanine contents are too low for collagen to he the main protein in the coating, (2) based on the hydroxyproline content, collagen could represent no more than 7W of the protein. The protein composition resembled that of qeneral lung protein, supporting evidence that the coatinq is formed from the cytoplasm of an alveolar macrophage by the adsorption of a preformed iron-protein complex (ferritin) or by the separate adsorption of iron and protein. ASBESTOS BODIES; LUNG; ASBESTOS; PHAGOCYTOSIS; HUMAN <4125> Rolt, P.V.; Mills, J.; Young, D.K., Experimental asbestosis in the quinea-pig., J. Pathol. Bacteriol., 92: 185-1815Bacteriol., 92: 185- (1966. Guinea pies were placed in inhalation chambers and dosed with four varieties of asbestos dust. Chrysotile asbestos dust (very fine particles) induced well-developed bronchiolitis after a few days, even when dust and fibers were absent from the lungs (microscopic inspection). Phagocytic cells were evident. After 30 weeks cell degeneration and fibrosis occurred along with polypoid growths in bronchioles. Later, asbestos bodies were numerous.
An evaluation of the substances handled by pipe insulation workers suggests that asbestos-containing materials present the most serious health hazards; the majority of substances were of minor concern as occupational hazards. Additional scientific data are needed to adequately define the health hazards of insulation occupations. clinical, electrocardiographic, and ph*siological observations were made of 21 asbestos workers whose length of exposure was 29.2 years and who showed asbestosis radiologically. most had chronic symptoms indicative of long term exposure. When 16/21 of these persons were compared to a group of 20 with similar age and asbestos exposure but with negative radiological signs, no stgnificant differences in the clinical findings were observed between the two qroups; however, the group with positive radiological signs had lower vital capacity, total lung capacity, and diffusion capacity than the other group. Electrocardiographic findings were unremarkable. Serpentine and asbestos dust inhibited growth and migration of embryonic lung cells in culture, with asbestos dust having the more pronounced effect. The early stages of mitosis were inhibited to a greater extent by asbestos dust than by serpentine dust. While serpentine is less acttve than asbestos, it is' not biologically inert and should be considered when present. ASBESTOS; CELL CULTURE; CYTOTOXICITY (<29>s Lynch, J.R.; Ayer, H.E., Measurement of dust exposures in the asbestos textile industry., Amer. Ind. Ryg. Assoc. J., 27(1): 431-437 (1966 an extrinsic factor in the pathogenesis of bronchogentc carcinoma and mesotheliona., Cancer, 19(8): 1143Cancer, 19(8): -1148Cancer, 19(8): (1966.

ASBESTOS
In a clinical study of 55 asbestos textile workers with pathologically proven asbesotosis, 28 maliqnant neoplasms are reported -23 bronchogenic carcinomas and 5 mesotheliomas (pleural and peritoneal); 26/28 were exposed to asbestos prior to 1936. The interval between neoplasm diagnosis and initial exposure ranged from 20-40 years. The frequent association of pulmonary asbestosis with bronchoqenic carcinoma (42%) and mesothelioma (8%) implicates asebstos as a carcinogenic agent. Topical applications of both croton and crocidolite oils on the denuded skin of rabbits initiated a significant tumor response when compared to control animals treated only with croton oil. nice treated with amosite and croton oils developed a high incidence of carcinoma. Though the asbestos oils induce weak tumor response compared to other agents, it is possible that both oils could play a significant role in cancer induction by asbestos.
Lung smears from autopsies of 500 people, 15 years of age and older, in Miami, Florida demonstrated asbestos bodies in 20% of the females and 30% of the males. In most, including all females examined, asbestos bodies were scanty and not Indicative of pulmonary changes. Tn view of the increasing diverse use, and the indestructabtlity of ashestos, it is anticipated that the frequency of malignancies of the lung will increase in the future. ASBESTOS; ASBESTOS BODIES; LUNG; CANCER; HUMAN (1435> Niecking, D.K., Pulmonary asbestosis with metastatic mesothelioma: case report., Amer. Surq., 32(5): 308-3 12 (1966) .
A male, age 61, employed 43 years as an insulation vorker, was seen at a clinic because of dypsnea. An x-ray of the chest revealed a consolidation in the lower left lung lobe with pleural thickening. A lobectomy revealed a fibrous tumor mass 12 cm in diameter which occupied most of the lobe. No asbestos bodies were seen in the tumor mass, but many were evident in the adjacent lung tissue. The patient died from bronchopneumonia and heart failure 2 years after the initial visit. Autopsy revealed a widespread metastatic pleural mesothelioma associated with asbestos fibers in the lunq. Asbestos is a general term describing several forms of fibrous minerals. Chrysotile is found in many areas of the world but is mined mostly in Pussia, Canada, and Rhodesia. The chemical constituents and structure of the fibers differ for the vartous types. There are many varied uses for asbestos minerals. Although the history of asbestos is F000 years old, the first case of asbestosis was not reported until 1907. A great rise in the production and use of asbestos has been accompanied by an increased incidence of asbestos-related disease. ASBESTOS; ASBESTOSIS; MtSOTHELIOMA; CHRTSOTItE; WHITE ASPESTOS; CROCIDOLITE; BLUE ASBESTOS; AMOSITE; ANTROP RYLLTEt <437> Anonvmous, The association of exposure to asbestos dust and cancer. A report from a working group of the International Union Against Cancer., Ann. Occup. Hyg., 8: 267-276 (1965).
Pmosite, anthophyllite, chrysotile, crocidolite and tremolite are the asbestos minerals of interest to a working group of the Geographical Patholoqy Committee of the I.U.C.C. The tumors associated with exposure to asbestos are lung carcinoma, diffuse pleural and peritoneal mesothelioma and possibly gastro-intestinal carcinoma and ovarian tumors. A latent period of 20 years or more may occur between initial exposure and the onset of tumors. Trace amounts of metals such as nickel and chromium are found in some asbestos fibers; the role of these in the development of tumors is unclear. Recommendations by the Committee relate to (1) dose-effect relationships; (2) epidemiological methods including surveys, clinical criteria, classification of chest radiographs, and lung function assessment; (3) pathological problems involving the diaqnosis of asbestos-related diseases and the classification of asbestosis; (4) preparation of standard reference samples; and (9) identification of asbestos in tissues. Accumulatinq evidence indicates a demonstrable rise of bronchogenic carcinoma and pleural mesothelioma in workers exposed to asbestos. Post mesotheliomas have been associated with crocidolite and chrysotile inhalation; however the additional influence of cigarette smoking or inhalation cf other dusts, industrial pollutants or trace metals associated with asbestos is undetermined. Although the production and use asbestos is large and widespread, certain asbestos industries can minimize occupational health hazards by engineering dust Acad. Sci., 132(1): 391-405 (1965).

STANDARDS
Serial observations of pulmonary function as related to clinical and radiological features were conducted on 17 asbestos workers who were exposed for 4-24 years, and subsequently were wtthdrawn from further exposure after developing alveolar capillary bloclk syndrome. Initial investigations showed moderately reduced vital capacity in half of the patients, slightly increased residual volume in 6, hyperventilation at rest and exercise in the majority, well preserved maximum breathing capacity and normal ventilation-perfusion relationships in all cases. Tn a 10-yr follow-up study in 13 of the workers, vital capacity was the most sensitive index of progressive changes in the disease; In half of the cases, reduced vital capacity correlated well with radiological changes, whereas in the rest, vital capacity was reduced in the %bsence of progressing radiological signs. Arterial carbon dioxide tension and pH remained unchanged, and changes in arterial oxygein saturation followed no significant trend. Because of national differences in compensation rules for ashestosis, only a radiological classification of the disease is practical for international agreement. If experts agree that radiological signs of pathological lung structures can be manifested only as disseminatled or squared opacities, these two characteristics can serve as a basis for new classification. To intensify the reproducibility of the x-ray films it is suggested that the symbol Of" be used for linear patterns chiefly occurring in asbestosis instead of the unalterable "Lf", and be combined with quantitative categories for small opacities. Large opacities might be characterized by the symbol "A" for beginntng confluence and by "B" and "C" for opacities having a diameter longer than S cm. Additional symbols would be welcomed to accomodate international peculiarities.
Filtration of either phosphate-low or Eagle's medium through a Seitz or rord's asbestos pad results in a considerable reduction of virus yield in both pig and hamster kidney cells that are grown in the medium. It has been established that the reductions were due to a toxic factor. However, the nature of the toxic factor or factors has not been examined.
The exchanqe of radiographic data between the United Kingdom and South Africa has established the. workability of the proposed T.t.C. (International Labor Office) Classification for asbestosis; however, if widely used, a standard set of films should be made available demonstrating the various pathological changes.
The incidence of asbestos bodies in the lungs of 100 autopsies from Pittsburgh and its environs was 41%. Amonq males the incidence of positive cases was higher (47%) than in women (34%). The highest relative incidence of positive cases was found in ages between 25 to 34 years; none vere found up to age 24. Interstitial fibrosis was observed in three cases, but no case of asbestosis or mesothelioma was found. Out of two cases of lung carcinoma observed, asbestos bodies were present in only one.  (1): 98-111 (1969 The importance of very small particles of asbestos dusts in the pathogenesis of asbestosis cannot be iqnored, since the bulk of the dust observed in both human and gutnea pig lungs is very small, much of it below Iu in length. Electron microscopic studies show that asbestosis is basically an intracellular process directly involving only alveolar macrophages and their derivatives. Tf exposure is continuous, there will always be free dust in the alveoli, bet results from animal experiments indicate that all dust will be phagocvtosed within a few weeks after the cessation of dusting.-This mav be true in humans as well. Although all sizes of fiber can be coated, some particles remain in the lung for long periods without becoming coated. In both human and guinea pig lung the asbestos body coating consisted of ferritin qranules approximately 60 A In diameter. ASPBSTOS; ASBESTOS BODIES; ASBESTOSIS; CHRtSOTILP; GIANT CELL; GUINEA PIG; HUMAN; MACROPHAGE <887> Dutra, P.R.; Carney, J.D., Asbestosis and pulsonary carcinoma., Arch. Environ. Health, 10(3): 416-423 (1965) Asbestosis often is not properly diagnosed because occupational exposure to asbestos is not established, and x-ray may not be diagnostic. Recently, the relationship between asbestosis and bronchogenic carcinoma has become more evident; this is based on the following observations: (1) approximately 13.8W of patients with asbestosis develop sguamous cell carcinoma of the lunq, and (2) the cancer is usually in one of the lower lobes where the number of asbestos fibers is greatest. Pleural mesothelioma is also observed in patients with asbestosis. Pathological, clinical and roentgenologic findings of asbestosis are discussed. Molt, P.!.; Mills, J.; Young, D.K., Experimental asbestosis with four types of fibers: Importance of small particles., Ann. N.Y. Acad. Sci. , 132 (1): 87-97 (1965).
Asbestosis is induced in the lungs of guinea pigs by the inhalation of chrysottle, amosite, crocidolite, or anthophylite dtst. In the later stages of the disease, there is an extension of the inflammatory reaction from the bronchioles into the surrounding lung, with progressive fibrosis of the lung, adenoid proliferation of the bronchiolar epithelium, and reticulinosis and fibrosis of the tracheal lymph qlands. Asbestos bodies are recognizable within seven days of exposure. These findings lead to the conclusion that dust particles are at least as l4th.al as long fibers. AMOSITTE; &NTIOPHYLLITE; ASBESTOS; ASBESTOS BODTYS; ASBOSTOSIS; CERTSOTILE; CROCIDOLITE; FIBROSIS; GUINEA PIG; LTING <461> Hueper, W.C., Occupational and non-occupational exposures to asbestos., Ann. N.Y. Acad. Sci., 132(1): 184-195 (1965).
Increased productiol and use of asbestos in the last 50 years has resulted in greater individual exposure of worcers to asbestos. This is reflected by growinq reports of asbestosis and asbestos-related cancers among various asbestos occupations in many countries. Epidesiological, data concerning the incidence of these diseases is sketchy, particularly in the United States and Canada. Retter legal protection through more uniform compensation laws is needed for asbestos workers internationally. ASBESTOS; ASBPSTOSIS; HUMAN; OCCUPATTONAL EXPOSURE; CANCER <4(62> Hunt, R., Routine lung function studies on 830 employees in an asbestos processinc. factory., Ann. W.Y. %cad. Sci., 132 (1) : 406-S20 (1965). lung function studies are valuable for screeninq potential employees and for assessing the health of occupationally exposed asbestos workers. Ashestosts can be detected by lung function studies before the appearance of gross changes which are necessary for x-ray and/or clinical diagnoses. In advanced stages of asbestosts, results from lung function studtes, x-ray and clinical tests can be correlated. There is evidence that men removed from -exposure four to five years ago, when the signs of the disease were minimal, are maintaining a reasonable functional level unlike similar men who remained in exposed departments.
ASBESTOS; ASBESTOSIS; OCCUPATIONAL EXPOSUIRE; DIAGNOSIS; 6UMAN <463> Jacob, G.; Anspach, M., Pulmonary neoplasia among Dresden asbestos workers., Ann. N.Y. Acad. Sci., 132(1): 5, 36-5148 (1965) Data presented summarizes the results of observations made among 2,636 workers in the Dresden asbestos industry from 1q52 to 1961, with particular reference to lung cancer and asbestosis. From the period 1951-1957, the incidence of lung cancer, with or without asbestosis, was not of statistical significance. However, for the period 1958-1964 a very sharp rise in the incidence of lunq cancer and pleural tumors was observed; lung caneer replaced cor pulmonale as the leading cause of death. The shift in frequency of these two leading causes of death among Dresden asbestos workers can be atttibuted to two factors: (1) improved industrial hygiene measures and (2) London., pp. 205-212, (1965).
Effects of the inhaiation and retention of dusts in the lungs of rats were examined following exposure to amosite, South African chrysotile, Canadian chrysotile or silica dust for 7 hr./day, 5 days a week, for 6 1/2 weeks. The dust concentration in each exposure chamber was approximately 25 mg/cubic meter as measured by gravimetric thermal precipitators. Histopathological examination of the lungs at 1, 28 and 56 days after the final exposure showed a more proqressive and marked tissue reaction to amosite than to silica or chrysotile. South African chrysotile Induced a greater reaction than Canadian chrysotile or silica; the interstitial reaction to both chrysotile forms was more pronounced at 2P days than at 56 days.
Occupational and domestic histories were established for 76 out of 83 patients with confirmed mesothelioma in the London Hospital. Forty (52.6%) had a history of asbestos exposure; 31 vere occupationally exposed and 9 were exposed domestically through relatives who worked with asbestos. The 36 cases having neither occupational nor domestic exposure lived in the immediate vicinity of an asbestos factory; 11 of these resided within 1/2 mile of the industry. Durations of exposure ranqed from 2 months to more than 50 years. The interval between initial exposure and death was 16 to 55 years with a mean of 29.4 years for factory workers, 38.4 yrs. for laggers and insulators, 37.9 for domestic exposure, and 48.6 years for residential exposure. The incidence of residential, occupational and domestic exposure in the mesotheliona aroup was highly significant when compared to exposure histories cf 76 control patients with gther diseases. The results show that riskof mesotheliona may arise from both occupational and incidental exposure to asbestos. The aim of this study was to establish the occupational histories and to trace any other exposure to asbestos in 83 patients with mesotheliona. Utilizing all available sources of information, it was determined that 52.6W of the patients with mesothelioma had been exposed to asbestos compared to 11.8% for the controls. Three main types of exposure are presented. Among the 36 patients with no nositive occupational history, 11 lived within half a mile of an asbestos industry. A symptomatology of pleural and peritoneal mesothelioma is presented. Rheumatoid factor in serum of individuals exposed to asbestos., Ann. N.Y. Acad. Sci., 132(1): 112-120 (1969 . The presence and titer of rheumatoid factors were determined in the sera of 315 asbestos insulation workers with occupational exposure varying from I to 54 years; most workers showed radiographic evidence of ashestosis that was graded from I to 3. A significant increase in rheumatoid factor was found only in patients with asbestosis of grade 2 or 3; among these patients the percentage of cases showing hemagglutination titer of 1:320 or more is 21.0W and 15.9(, respectively. The factor found reacts with human gama qlobulins. ASBESTOS; ASBESTOSTS; INSUUT-ON WOBKERS; OCCUPATIONAL FIPOSURE; RHEUMATOID FACTOR <474> Schall, F.L., Present threshold limit value in the U.S.A. for asbestos dust: A critique., Ann. W.Y. Acad. Sci., 132 (1) : 316-321 (1965).
The present threshold limit value for asbestos in the United States is 5. Oppcf for a daily eight hour exposure, 40 hours/week; this value was adopted several years ago. Present criticisms are! (1) the value relates to the prevention of asbestosis but not other asbestos-related diseases, (2) data was obtained from the textile industry only, (3) variations in the nature of the dust were not considered, (1) the value is based upon dust counts of all particles, fibrous and particulate, asbestos or not, and (5) dust counts taken were averaqed. ASBESTOS; STANDARDS <475> Selikoff, I.J., The occurrence of pleural calcification asong asbestos insulation workers., Ann. N.Y. Acad. Sci., 132(1): 351-367 (1965).
Roentgenological evidence of pleural calcification was found in 150 of the 1,1 17 asbestos insulation workers examined. Calcification rarely occurred in less than 20 years from onset of exposure. Roth unilateral and bilateral calcifications were observed; approximately half were bilateral.
Extensive pleural calcification tended to be bAilateral. Although bilateral calification is almost pathognomontc of asbestosis in the absence of traumatic or infectious pleural disease, unilateral calcification is almost as strongly diagnostic. Pazards associated with asbestos exposure were investigated in 1522 insulation workers in the New York -New Jersey area. Among the 392 workers with more than 20 years of exposure, 339 casew of asbestosis and 11 pleural cancer cases were observed. Neoplastic complications of asbestos exposure were studied among 307 consecutive deaths in this group of men. The incidence of lung cancer was seven times greater than expected and cancer of the gastrointestinal tract was three times greater than expected. Ten cases of nesothelioma were found. No cancers were observed in workers with less than 20 years work experience. Ten deaths from mesotheliomas, 4 of the pleura and 6 of the peritoneum, vere verified in.a study of 307 consecutive deaths (19413-19641 among asbestos-insulation workers in New York and New Jersey. This incidence of more than 3% is remarkably high for such a rare a tumor. Tn a prospective study of the general population, only 3 deaths out of 31,652 were due to sesothelioma of the pleura. Mesothelioma was further associated with asbestos by the autopsy verification of a pleural and 3 peritoneal mesothelionas among 26 asbestotic cases, and by the finding of asbestos bodies in lung sections from more than 25% of the mesothelioma cases. It is apparent that mesothelioma must be (1 9fi ' . The International Classification of Pneumoconiosis was modified to facilitate diagnosis of asbestosis. All principal radiological features are described both qualitatively and quantitatively. The code letters "Lc" and "Lf" denote linear opacities; the quantitative assessment 1/3, 2/3, and 3/3 indicates the extent of lung involvement. Additional symbols are used for related complications. A critique of the health hazards associated with asbestos is presented by an industrialist. An appeal is made for more accurate investigation and reporting of asbestos related hazards, and for classification of asbestos workers and asbestos products. Isolated studies may be interesting, but the true picture of the bioloqical effects of asbestos wtll emerge only when there is a broad study conducted by an impartial agency on a nation-wide scale. Oral and intrapleural administration of soft chrysotile,' harsh chrysotile or amosite in hamsters at a dose of 25 mg induced mesotheliomas resembling those found in man. Islands of epithelial-like cells, sosetimes lining narrow clefts, were found In pleural adhesions of hamsters that did not develop tumors. These islands tre of interest because they may be precursors of tubular types of metheltomas. Smither, W.J., Secular changes in asbestosis in an asbestos factory., Ann. N.Y. Acad. Sci., 132(1): 166-181 (1965).
One way to study secular changes in the incidence of asbestosis is to compare the average length of exposure before the onset of certifiable disability.
Of 26 new cases certified since 1960, the average exposure was 17.5 years (range equals 4 to 35 years). Disability was only 10 in 21 of the 26 cases. Most (88%) were referred for physiological testing to confirm asbestosis. Sputum asbestos bodies are evidence of asbestos exposure only. ASBESTOSIS; OCCUPATIONAL EXPOSUPR; HUMAN; ASBESTOS; ASBESTOS BODIDES <485> Steel, S.J.; Boyd, J., Pleural calcification and sesothelioma following exposure to asbestos., Brit. J. Dis. Chest, 59(3): 130-134 (196S). Ten years after exposure to asbestos as a storekeeper, a 63-year old man developed *esotheliona with pleural thickening and effusion of the left side. The patient was rehospitalized with symptcms ot progressive dyspnea and dysphagia; chest x-ray showed increased left pleural thickening and displacement of the sediastinum to the right. Histologic examination of the biopsy specimen revealed the presence of mesotbelioma of the pleura with an asbestos body present in the adjacent long. The disease was fatal.
Evidence is mounting that links lung cancer with asbestosis, and malignant neoplasms with asbestos dust. Pany case reports are reviewed. Until we know the answers to some of the questions posed by the recent findinos all exposure to asbestos dust should be considered as hazardous, and supervision should be extended to insulation workers who may be intermittently but nevertheless heavily exposed to asbestos dust. CANCER; LUNG: ASBESTOSIS: NEOPLASM; HUMAN; OCCUPATIONAL FXPOSURF; NOW-OCCUPATIONAL EXPOSURP <496> 'Riure, J.; Soderhols, P.; Widiesky, J., Cardiopulmonary function studies in workers dealing with asbestos and alasswool., Thorax, 19: 22-27 (1964) .
Because asbestos fibers reportedly are not transported by the pulmonary lymphatics, one single massive exposure might lead to the same stage of fibrosis as a chronic low level exposure. men exposed to glasswool showed no detectable functional impairment; asbestos, however, caused marked restriction in diffusing capacity -3 out of 8 asbestos workers exhibited pathologically raised pulmonary artery pressure. Buchanan, W.D., The association of certain cancers with ashestosis., Proceedings of the Fourteenth International Concress of occupational Health (Madrid, 1963). Exerpta Medica Foundation, New York., Vol. II: 617-619 (1964) British epidemiologic data on pulmonary and other cancers are updated to 1962. Ashestosts was present at autopsy in 549 cases from 1924 to 1962 -364 males and 18; females. Death from lunq cancer or mesothelioma of the pleura or the peritoneum is more likely if asbestosis is present; but no evidence exists that an increased risk prevails for those persons exposed that do not have asbestosis.
CANCER; ASBrSTOSIS; OCCUPATIONAL EXPOSURE; LUNG; MESOTRHLIOMA; HUMAN; PLEURA; PERITONEUM <498> Davis, J.M.G., An electron microscopy study of the effect of asbestos dust on the lung., Brit. J. Exp. Pathol., 44 fl4): 1454-464 (19614). Rats and quinea pigs were exposed to a high concentration of chrysotile dust for 95 and 77 days respectively. Pathological changes occurred in 3 stages (1) formation of small nodular giant cell lesions in walls of terminal bronchioles (2) fibrosing interstitial pneumonia (3) consolidation of lungs as exposure progressed. Remission of the consolidation was seen in rats which were removed from exposure, but this was not the case in guinea pigs. C'hrysotile dust was seen only in alveolar sacrophages; other cells apparently are unable to phaqocytize this material. The dust which had been in lungs for some morths showed signs of dissolution by body fluids. An agqregation of ferritin material around asbestos particles may be the start of asbestos body formation. Some capillary walls in dusted lungs were thicker than usual in the area of the blood-air interface. the basement membrane in these areas was uneven in outline and numerous invaginations in the cytoplasm of epithelial and endothelial cells were evident. LUNG; ASBESTOS; CRRYSOTILE; RAT; GUINEA PIG; MACROPHAGE; ASBESTOS BODIES; PRAGOCYTOSIS <1499> Davis, J.R.G., The ultrastructure of asbestos bodies from human lung., lrit. J. Nxp. Pathol., 145(6): 642-6146 (1964).
The electron-microscope study of asbestos bodies from human lung mirrored the results from guinea pig studies--embedding sites were the same, located intracellularly in macrophages and fibroblasts, or seated among the collagen fibers. The asbestos body coating consisted mainly of ferritin granules about 60 A in diamter. Segmentation of the asbestos body may result from its deposition as separate globules or by the splitting of a previously smooth coat.
Irregularly shaped aggregates of ferritin contained Guinea pigs were exposed to chrysotile dust for 18 hrs a day for 6 weeks. The first sign of asbestos body formation was the accumulation of dense qranules, (orobably ferretini approximately 60 A in diameter around the asbestos fiber. Partly or completely formed asbestos bodies were found in 3 sites only --in alveolar macrophages, in fibroblasts, or embedded among collagen fibers ir fibrotic areas. During the duration of the experiment, there was no evidence of the breakup of asbestos bodies in guinea pig lungs. Thoraic Cardiovas. Surg., 47(5): 577-589 (1964). Primary pulmonary sarcoma is clinically indistinquishable from carcinoma until diaqnosis is made by biopsy at brochoscopy or at thoractomy. In a S4-year-old newspaperman with primary pulmonary sarcoma, anthracotic pigment and asbestos bodies were present within the tumor and within adlacent lung tissue. occupational history revealed 16 years of asbestos exposure as a pipe insulator. This is the first reported case in which pulmonary asbestosis was associated with primary pulmonary sarcoma. A review of 66 published cases of ortmary sarcoma in the bronchus or peripheral lung is included.
Out of 2383 radiologic examinations, 166 cases of definite uncomplicated asbestosts were diagnosed; 59 shovel calcified pleural plaques only. No true correlation was discerned between plaque formation and the factors which influence devel6pment. Further, neither the period and type exposure nor age could be related to the size or distribution of Investigations centered on the 1q22 insulation workers of the Asbestos Workers Union in the New York metropolitan area. Of the 632 who entered the trace before 1943 and were traced through 1962, 05 died of lunq or pleural cancer; only 6.6 were expected. Four nesothelionas in 255 deaths is an extraordinarily high incidence of sUch a rare tumor.
Twenty-nine died from stomach, colon, or rectum cancer compared with Q.4 expected; there may be an etiological relationship between industrial asbestos exposure and carcinoma of the gastrointesttnal tract.  (Madrid, 1963) . Exerpta Medica Foundation, New York., Vol. IT: 608-610 (1964).
Asbestosis may cause disablement without being detectable radiologically. In 108 asbestotic subjects studied, all had worked in crocidolite or amosite mines; radiologically, at autopsy, there were 47 cases of slight asbestosis, 42 moderate, and 19 marked. Injection of 25 mg asbestos into the right pleural cavity of golden Syrian hamsters caused extensive pleural reaction with granulonatous inflammation and fibrous tissue overgrowth, causinq lung lobes to bind together, to chest wall, and to the diaphragm. Results indicate that the Syrian hamster may be a sensitive animal model for testing asbestiform materials.
Continuing investigations of cases of diffuse pleural mesothelionas in South Africa have shown that 110 out of the 120 cases recorded since 1956 were exposed to crocidolite (blue) asbestos. Interestingly more than half the cases from the Cape asbestos fields were not occupationally exposed. The occupational group showed no correlation between the severity of asbestosts and the presence of tumor. Oils and waxes containing polycyclic aromatic hydrocarbons on the crocidolite fibers may be intimately involved in the carcinogenic effect of This review sumnarizes the asbestosis problem in South Africathe incidence, pathogenesis, pathology, and malignancy. Analysis showed that 3 main problems remain unsolved: (a) The particular property of the dust which causes fibrosis and how it does thts; (b) The length of exposure or dust load necessary to produce such fibrosis; (c) The reason for the increased incidence of pulmonary malignancy in asbestosis. For the years 1960 and 1961 nearly half the certified cases of asbestosis occurred in insulators. Most victiis started work in the asbestos industry before 1945. Massive industrial expansion since then implies more cases in the future. Insulators lag boilers and pipes witb a plaster consisting of 85% magnesia and 15% amosite; laggers apply a coat of wet plaster by hand on cover sections wired to the boiler.
Folloving the injection of asbestos into the air sacs of white Leghorn chickens, tumors formed in two birds of the 30 which survived.f or 1 year or more. A mucus-secreting adenocarcinona appeared about I year after the injection of commercial asbestos into the right air sac of one bird. The tumor involved the syrinx, the proventiculus, the lungs and the ovary. The  Lung spears were examined from more than 500 consecutive autopsies in Cape Town, South Africa. Golden-yellow asbestos bodies, were identified from 132 cases -30% of the males and 20% of the females.
This appeared to result from exposure to urban air contaminated with asbestos, rather than to occupational exposure. Basal asbestosis rarely leads to pulmonary disease or disability but is etiologically involved in mesothelioma of the pleura and peritoneum. For Q hours per day, S days per veek, guinea pigs, rabbits and monkeys were exposed to asbestos dusts: relatively pure chrysotile, pure amosite, and crocidolite consisting of ironstone and silica with only 10% asbestos fiber. Histological examinations at monthly intervals revealed: (1) chrysotile dust produced severe lestons in the lungs of guinea pigs, sliqht fibrosis in monkeys, and no effect in rabbits; (2) amosite dust induced marked lesions in all three mammals; and (3) impure crocidolite dust caused severe disease in guinea pigs and respiratory infections in these animals were more severe tban for animals treated with pure dusts. The South African view of industrial cancer is developed under section headings such as: historical outline of industrial development; industrial cancer; time factor; prevention; mining industry (silicosis, asbestosis and coal pneumoconiosis); non-mining industry (dusty trades and metal); natural environment; co-carcinogens and synergism; and atmospheric pollution. WUMAN; OCCUPATIONAL EIXPOSURE; ASBESTOSIS; ASBESTOS NII WING <523> Webster, I., Asbestosis in non-experimental animals in South Africa., Nature, 197 (4866): 50 (1963).
Pactors influencing the rate of massive fibrosis and the role of tuberculous infection in the development of progressive fibrosis are not fully known.
Preventive measures age4inst inhalation dtsease and in planning for treatment of the later stages of pneumocontosis must be emphasized. rour cases of asbestosis in asbestos workers employed at a textile factory are depicted. Tables in this paper present a scheme for the international classification of mineral dust diseases. ASRESTOS; ASRESTOSIS; OCCUPATIONAL EXPOSURE; FIBROSIS; PNEUMOCONIOSIS <525> Cartier, P.R.; Gross, P., Nonoccupational diffuse pulsonary fibrosis., Arch. Environ. Health, 4(1): 79-86 f1962) A worker exoosed to asbestos dust for 38 years developed diffuse chronic interstitial fibrosis; chronic interstitial pneumonitis was evident for 32 years prior to death. Postmortem examination of a sinqle section from each lung revealed no asbestos bodies, indicatinq that the disease was not related to asbestosis. Histological data implicated bronchopneumonia as the immediate cause of death. The case illustrates that the clinical diagnosis of pneumoconiosis cannot be based on presumptive evidence alone. Rather, diagnoses should include (1) knowledge of significant exposure to ashestos dust and (2) knowledge of the clinical progression of the disease. Lung carcinoma was associated with 11 cases of asbestosis; seven had a history of known asbestos exposure. In all cases, asbestos bodies were found in the tumor area. ASBESTOS; OCCUPATTONAL EXPOSURE; ASBESTOS BODIES; LUNG; CANCER; CARCINOMA ASSBSTOSIS; HUMAN Environmental Health Perspectives <535> Bader, N.!.; Bader, P.A.; Selikoff, T.J., Pulmonary function in asbestosis of the lung., Amer. J. Wed., 30: 235-242 (1961) Pulmonary function tests of 17 asbestos factory employees sbowed relatively normal vital capacity in half of the workers and reduced capacity in the rest. Residual volume was slightly increased in 6 workers and unaltered in others. Maximus breathing capacity was well preserved in all cases. Pathological changes produced in asbestosis are reviewed in relation to the alveolar capillary block syndrome.
Xt Massachusetts automobile mechanic who undercoated cars for 5 years prior to his illness presented with diffuse bilateral infiltration of the lungs by minute, discrete nodular densities and considerable accentuation of the peribronchial perivascular markings, particularly of the lower lobes. A resultant state-wide survey corrected problems caused from asbestos-asphalt type undercoating compound: pre-employment and periodic x-rays, rotation of workers, use of approved respiratory and eye protection devices and mechanical ventilation of the vork area were recommended as protective measures.
An historical account details that past work conditions in asbestos textile factories were hazardous due to htgh dust levels; present dust controls have greatly reduced dust particle counts to minimize the hBzards of silicosis and asbestosis; routine medical examinations and x-rays of all workers enable early detection of any lung disease. An Australian patient with a 5-year history of diabetes mellitus was diagnosed as having rheumatoid arthritis; further examination disclosed asbestosis in the absence of classical radiological changes which characterize the disease. The patient was employed for 15 years in a factory which manufactured asbestos-cement board using amosite, chrysottle, and crocidolite. Estimated exposure approximated an average density of 0.3 million particles per cubic foot; the total cummulative exposure was about 4 million particle-yeRrs per cubic foot. Accordingly, the man was exposed to low levels of asbestos dust.