Appraisal of interpretation criteria for the comparative intradermal tuberculin test for diagnosis of tuberculosis in cattle in central Ethiopia.

Aklilu Lemma Institute of Pathobiology, Addis Ababa University, P.O. Box 1176, Addis Ababa, Ethiopia. gobenaameni@yahoo.com

Accurate detection and removal of infected cattle, using immunodiagnostic tests such as the comparative intradermal tuberculin (CIDT) test, are the basis of control strategies for bovine tuberculosis (TB). According to the Office des Internationale Epizooties recommendation, the cutoff point for positivity of the CIDT test, calculated as the difference between skin thicknesses after bovine tuberculin (B) and avian tuberculin (A) injections (B - A), is >4 mm. This cutoff point is used worldwide, although it is likely that local conditions influence test performance. Thus, this study was formulated to determine CIDT test cutoff points applicable to cattle in central Ethiopia. Receiver operating characteristic analysis was performed for the CIDT test, using data from 186 Bos indicus (zebu) and Bos taurus (Holstein) cattle. Detailed postmortem examination for the presence of TB lesions was used to define disease status. At a cutoff of >2 mm, CIDT test sensitivity was 69% (95% confidence interval [95% CI], 58.5 to 79%), while it was 59% (95% CI, 49 to 69%) at a cutoff of >4 mm. In contrast, specificities of the CIDT test at these two cutoff values were identical, at 97% (95% CI, 89 to 100%). Thus, the maximum sensitivity of the CIDT test can be realized using a >2-mm cutoff without affecting specificity. The apparent prevalence was significantly (chi(2) = 13.56; P < 0.001) higher at a cutoff of >2 mm (16.0%; n = 5,424) than at a >4-mm cutoff (13.5%; n = 5,424). Nonetheless, no significant difference (chi(2) = 2.15; P = 0.14) in true prevalence was observed at a cutoff of >2 mm (19.6%) and at a cutoff of >4 mm (18.5%). Thus, our study demonstrates the importance of defining local, relevant cutoff values to maximize test sensitivity, and we suggest the application of the >2-mm cutoff for testing of cattle in central Ethiopia.

PMID: 18495847 [PubMed - indexed for MEDLINE]

PMCID: PMC2519295

Phylogenetic analysis and heterologous expression of surface layer protein SlpC of Bacillus sphaericus C3-41.

State Key Laboratory of Virology, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan 430071, China.

The surface layer protein encoding genes from five mosquito-pathogenic Bacillus sphaericus isolates were amplified and sequenced. Negative staining of the S-layer protein extracted from the cell wall of wild-type B. sphaericus C3-41 was prepared. It showed a flat-sheet crystal lattice structure. Two genes encoding the entire and N-terminally truncated S-layer protein (slpC and DeltaslpC respectively), were ligated into plasmid pET28a and expressed in Escherichia coli. SDS-PAGE revealed that about 130 KD and 110 KD proteins could be expressed in the cytoplasm of recombinant E. coli BL21(pET28a/slpC) and E. coli BL21(pET28a/DeltaslpC) respectively. Furthermore, an intracellular sheet-like or fingerprint-shape structure was investigated in two recombinant strains, which expressed SlpC and DeltaSlpC protein respectively, by ultrathin microscopy study, but bioassay results suggested that the S-layer protein of wild B. sphaericus C3-41 and recombinant E. coli BL21 (pET28a/slpC) have no direct toxicity against mosquito larvae. These results should provide information for further understanding of the function of S-layer protein of pathogenic B. sphaericus.

PMID: 18460813 [PubMed - indexed for MEDLINE]

Distribution of ABO phenotypes in patients with congenital cardiac defects.

Department of Anesthesiology, Perioperative and Pain Medicine Children's Hospital, Boston, and Harvard Medical School, Boston, MA 02115, USA. Kirsten.odegard@childrens.harvard.edu

BACKGROUND: Cardiac anomalies are among the most frequent congenital malformations, but the basic underlying causes for most cardiac defects remains undetermined. Some 40 years ago, a higher incidence of blood group B was reported in a small number of African-American children with congenital cardiac defects. In this study, we sought to re-evaluate this association using a larger population.Methods and RESULTS: We collected data from 1985 patients undergoing cardiac surgery from July, 2000, through December, 2004. We divided the patients into 6 subgroups according to their diagnosis. We then compared the prevalence of ABO phenotypes between the patients and the general population of the United States of America by chi-square analysis. There were no significant differences in the distribution of the ABO phenotypes amongst the subgroups of those with congenital cardiac disease, or any for subgroup compared to the general population.CONCLUSION: While statistical significance is influenced by the size of the population within the United States of America and the small numbers within each of our subgroups of patients with congenital cardiac disease, we have been unable to show any relationship between the distribution of ABO phenotypes and the existence of congenital cardiac disease.

PMID: 18460227 [PubMed - indexed for MEDLINE]

The members of the Bacillus cereus group are commonly present contaminants of fresh and heat-treated milk.

Department of Microbiology, Institute of Biology, University of Bialystok, 20B Swierkowa Street, 15-950 Bialystok, Poland.

To determine the level of milk contamination by Bacillus cereus sensu lato, 44 samples were collected from a dairy farm and two independent dairies in northeastern Poland. A total of 680 B. cereus sensu lato isolates were recovered. Based on spore counts, their highest level in milk was found during the spring and summer months. Although significant variations in chromosomal DNA polymorphisms among B. cereus sensu lato isolates were noted based on repetitive element sequence polymorphism (rep-PCR) and pulse-field gel electrophoresis (PFGE), indistinguishable B. cereus isolates were observed in all sampling points and locations. Both B. cereus sensu stricto/Bacillus weihenstephanensis and Bacillus thuringiensis cultured from milk harbored nheA, hblA, and cytK in, respectively, 80%, 55%, and 60% of the isolates. With respect to Bacillus mycoides/Bacillus pseudomycoides, 30% and 70% of theses isolates harbored, respectively, nheA and hblA. The presence of cytK was not detected in any isolate. Our data show the occurrence of potentially toxic B. cereus s.l. in both raw and heat-treated milk, thus emphasizing the requirement for precautions that prevent spore germination and vegetative proliferation by keeping the milk at low temperatures during all steps of production and dispensation to the consumers.

PMID: 18456114 [PubMed - indexed for MEDLINE]

[Reporting chronic hepatitis B and C in Denmark]

Balslev U, Grønbaek K, Clausen MR, Krarup H, Krogsgaard K, Kromann-Andersen H, Laursen AL, Lindberg J, Lunding S, Møller A, Nielsen H, Nielsen JO, Obel N, Schlichting P, Tage-Jensen U, Schaffa-litzky de Muckadell OB.

Infektionsmedicinsk Afdeling, Hvidovre Hospital,DK-2650 Hvidovre. ninaweis@dadlnet.dk.

INTRODUCTION: It became mandatory to report cases of chronic hepatitis B and C in Denmark in May 2002. The "treating doctor" is obliged to make the report. The purpose of this study is to find out how many patients with chronic hepatitis B or C who are monitored in the Danish health care system are reported to the State Serum Institute (SSI) and to find out who makes the report and from these numbers to estimate the total number of patients in Denmark with chronic hepatitis B and C. MATERIALS AND METHODS: Patients with chronic hepatitis B or C who were reported to the SSI before June 20th 2006 were cross-referenced with patients included in the Danish Database of Hepatitis B and C (DANHEP) on the basis of their social security number. RESULTS: The study found that only 50% of patients monitored at Danish hospitals with chronic hepatitis B or C are registered with the SSI. Respectively 47% and 38% of these were registered by their general practitioner, a few percent by a doctor whose place of employment is not registered, and the rest by doctors working at hospitals. CONCLUSION: This study demonstrates that the reporting of patients with chronic hepatitis B and C in Denmark is considerably inadequate. It is important that general practitioners as well as doctors working at hospitals are aware of their duty to report these diseases. An optimal reporting rate could be achieved by making it mandatory to notify the laboratory diagnosis of chronic hepatitis B and C as well as establishing an electronic reporting system, where data from laboratories are cross-referenced with clinical and epidemiological data.

PMID: 18454929 [PubMed - indexed for MEDLINE]

Comprehensive analysis of HLA-A, HLA-B, HLA-C, HLA-DRB1, and HLA-DQB1 loci and squamous cell cervical cancer risk.

Program in Epidemiology, Fred Hutchinson Cancer Research Center, Seattle, WA 98109, USA. mmadelei@fhcrc.org

Variation in human major histocompatibility genes may influence the risk of squamous cell cervical cancer (SCC) by altering the efficiency of the T-cell-mediated immune response to human papillomavirus (HPV) antigens. We used high-resolution methods to genotype human leukocyte antigen (HLA) class I (A, B, and Cw) and class II (DRB1 and DQB1) loci in 544 women with SCC and 542 controls. Recognizing that HLA molecules are codominantly expressed, we focused on co-occurring alleles. Among 137 allele combinations present at >5% in the case or control groups, 36 were significantly associated with SCC risk. All but one of the 30 combinations that increased risk included DQB1*0301, and 23 included subsets of A*0201-B*4402-Cw*0501-DRB1*0401-DQB1*0301. Another combination, B*4402-DRB1*1101-DQB1*0301, conferred a strong risk of SCC (odds ratio, 10.0; 95% confidence interval, 3.0-33.3). Among the six combinations that conferred a decreased risk of SCC, four included Cw*0701 or DQB1*02. Most multilocus results were similar for SCC that contained HPV16; a notable exception was A*0101-B*0801-Cw*0701-DRB1*0301-DQB1*0201 and its subsets, which were associated with HPV16-positive SCC (odds ratio, 0.5; 95% confidence interval, 0.3-0.9). The main multilocus associations were replicated in studies of cervical adenocarcinoma and vulvar cancer. These data confirm that T helper and cytotoxic T-cell responses are both important cofactors with HPV in cervical cancer etiology and indicate that co-occurring HLA alleles across loci seem to be more important than individual alleles. Thus, certain co-occurring alleles may be markers of disease risk that have clinical value as biomarkers for targeted screening or development of new therapies.

PMID: 18451182 [PubMed - indexed for MEDLINE]

PMCID: PMC2662593

MR1 uses an endocytic pathway to activate mucosal-associated invariant T cells.

Department of Pathology and Immunology, Washington University, St. Louis, MO 63110, USA.

Like CD1d-restricted iNKT cells, mucosal-associated invariant T cells (MAITs) are "innate" T cells that express a canonical TCRalpha chain, have a memory phenotype, and rapidly secrete cytokines upon TCR ligation. Unlike iNKT cells, MAIT cells require the class Ib molecule MHC-related protein I (MR1), B cells, and gut flora for development and/or expansion, and they preferentially reside in the gut lamina propria. Evidence strongly suggests that MAIT cell activation is ligand-dependent, but the nature of MR1 ligand is unknown. In this study, we define a mechanism of endogenous antigen presentation by MR1 to MAIT cells. MAIT cell activation was dependent neither on a proteasome-processed ligand nor on the chaperoning by the MHC class I peptide loading complex. However, MAIT cell activation was enhanced by overexpression of MHC class II chaperones Ii and DM and was strikingly diminished by silencing endogenous Ii. Furthermore, inhibiting the acidification of the endocytic compartments reduced MR1 surface expression and ablated MAIT cell activation. The importance of the late endosome for MR1 antigen presentation was further corroborated by the localization of MR1 molecules in the multivesicular endosomes. These findings demonstrate that MR1 traffics through endocytic compartments, thereby allowing MAIT cells to sample both endocytosed and endogenous antigens.

PMID: 18443227 [PubMed - indexed for MEDLINE]

PMCID: PMC2373850

Retrivability in The Danish National Hospital Registry of HIV and hepatitis B and C coinfection diagnoses of patients managed in HIV centers 1995-2004.

Department of Infectious Diseases, Copenhagen University Hospital, Rigshospitalet, Copenhagen, Denmark. niels.obel@rh.regionh.dk

BACKGROUND: Hospital-based discharge registries are used increasingly for longitudinal epidemiological studies of HIV. We examined completeness of registration of HIV infections and of chronic hepatitis B (HBV) and hepatitis C (HCV) coinfections in the Danish National Hospital Registry (DNHR) covering all Danish hospitals. METHODS: The Danish HIV Cohort Study (DHCS) encompasses all HIV-infected patients treated in Danish HIV clinics since 1 January 1995. All 2,033 Danish patients in DHCS diagnosed with HIV-1 during the 10-year period from 1 January 1995 to 31 December 2004 were included in the current analysis. We used the DHCS as a reference to examine the completeness of HIV and of HBV and HCV coinfections recorded in DNHR. Cox regression analysis was used to estimate hazard ratios of time to diagnosis of HIV in DNHR compared to DHCS. RESULTS: Of the 2,033 HIV patients in DHCS, a total of 2,006 (99%) were registered with HIV in DNHR. Of these, 1,888 (93%) were registered in DNHR within one year of their first positive HIV test. A CD4 < 200 cells/microl, a viral load > or = 100,000 copies/ml and being diagnosed after 1 January 2000, were associated with earlier registration in DNHR, both in crude and adjusted analyses. Thirty (23%) HIV patients registered with chronic HBV (n = 129) in DHCS and 126 (48%) of HIV patients with HCV (n = 264) in DHCS were registered with these diagnoses in the DNHR. Further 17 and 8 patients were registered with HBV and HCV respectively in DNHR, but not in DHCS. The positive predictive values of being registered with HBV and HCV in DHCS were thereby estimated to 0.88 and 0.97 and in DNHR to 0.32 and 0.54. CONCLUSION: The study demonstrates that secondary data from national hospital databases may be reliable for identification of patients diagnosed with HIV infection. However, the predictive value of co-morbidity data may be low.

PMID: 18439245 [PubMed - indexed for MEDLINE]

PMCID: PMC2386497

Ni(II) ions dysregulate cytokine secretion from human monocytes.

Department of Oral Biology, Medical College of Georgia, Augusta, Georgia, USA.

Nickel-containing alloys are used in dentistry because of their low cost, but poor corrosion behavior increases their risk of causing adverse biological responses. Intraorally, nickel-containing alloys accumulate bacterial plaque that triggers periodontal inflammation via toxins such as lipopolysaccharide (LPS). Recent evidence suggests that in monocytes, Ni(II) amplifies LPS-induced secretion of several cytokines that mediate periodontal destruction. Thus, we investigated the effects of Ni(II), with or without LPS, on the secretion of a broader array of cytokines from monocytes. We then measured monocytic expression of two proteins, Nrf2 and thioredoxin-1 (Trx1), that influence the regulation of cytokine secretion. Cytokine arrays were used to measure the effects of 0-50 microM Ni(II) on cytokine secretion from human THP1 monocytes, with or without LPS activation. Immunoblots were used to estimate Nrf2 and Trx1 levels. Our results indicate that both Ni(II) alone and Ni(II) with LPS have broad-based effects on cytokine secretion. Ni(II) increased Nrf2 levels by threefold, and LPS amplified the effects of Ni(II) by 10-fold. Trx1 levels did not change under any condition tested. Our results suggest that Ni(II)-induced changes in cytokine secretion by monocytes are diverse and may be influenced by Nrf2 but are not likely influenced by changes in whole-cell Trx1 levels. Copyright 2008 Wiley Periodicals, Inc.

PMID: 18437699 [PubMed - indexed for MEDLINE]

CD83 expression in CD4+ T cells modulates inflammation and autoimmunity.

Department of Mucosal Immunity, Helmholtz Centre for Infection Research, Braunschweig, Germany.

The transmembrane protein CD83 has been initially described as a maturation marker for dendritic cells. Moreover, there is increasing evidence that CD83 also regulates B cell function, thymic T cell maturation, and peripheral T cell activation. Herein, we show that CD83 expression confers immunosuppressive function to CD4(+) T cells. CD83 mRNA is differentially expressed in naturally occurring CD4(+)CD25(+) regulatory T cells, and upon activation these cells rapidly express large amounts of surface CD83. Transduction of naive CD4(+)CD25(-) T cells with CD83 encoding retroviruses induces a regulatory phenotype in vitro, which is accompanied by the induction of Foxp3. Functional analysis of CD83-transduced T cells in vivo demonstrates that these CD83(+)Foxp3(+) T cells are able to interfere with the effector phase of severe contact hypersensitivity reaction of the skin. Moreover, adoptive transfer of these cells prevents the paralysis associated with experimental autoimmune encephalomyelitis, suppresses proinflammatory cytokines IFN-gamma and IL-17, and increases antiinflammatory IL-10 in recipient mice. Taken together, our data provide the first evidence that CD83 expression can contribute to the immunosuppressive function of CD4(+) T cells in vivo.

PMID: 18424708 [PubMed - indexed for MEDLINE]

Borrelia infection and risk of non-Hodgkin lymphoma.

Department of Epidemiology Research, Statens Serum Institut, Copenhagen, Denmark. cko@ssi.dk

Reports of the presence of Borrelia burgdorferi DNA in malignant lymphomas have raised the hypothesis that infection with B. burgdorferi may be causally related to non-Hodgkin lymphoma (NHL) development. We conducted a Danish-Swedish case-control study including 3055 NHL patients and 3187 population controls. History of tick bite or Borrelia infection was ascertained through structured telephone interviews and through enzyme-linked immunosorbent assay serum analyses for antibodies against B. burgdorferi in a subset of 1579 patients and 1358 controls. Statistical associations with risk of NHL, including histologic subtypes, were assessed by logistic regression. Overall risk of NHL was not associated with self-reported history of tick bite (odds ratio [OR] = 1.0; 95% confidence interval: 0.9-1.1), Borrelia infection (OR = 1.3 [0.96-1.8]) or the presence of anti-Borrelia antibodies (OR = 1.3 [0.9-2.0]). However, in analyses of NHL subtypes, self-reported history of B. burgdorferi infection (OR = 2.5 [1.2-5.1]) and seropositivity for anti-Borrelia antibodies (OR = 3.6 [1.8-7.4]) were both associated with risk of mantle cell lymphoma. Notably, this specific association was also observed in persons who did not recall Borrelia infection yet tested positive for anti-Borrelia antibodies (OR = 4.2 [2.0-8.9]). Our observations suggest a previously unreported association between B. burgdorferi infection and risk of mantle cell lymphoma.

PMID: 18424667 [PubMed - indexed for MEDLINE]

Weakened feedback abolishes neural oblique effect evoked by pseudo-natural visual stimuli in area 17 of the cat.

Center for Brain Science Research, School of Life Sciences, Fudan University, Shanghai 200433, PR China.

The psychological oblique effect, a well-known phenomenon that humans and some mammals are more visually sensitive to cardinal (vertical and horizontal) contours than to oblique ones, has commonly been associated with the overrepresentation of cardinal orientations in the visual cortex. In contrast to the oblique effect, however, Essock et al. [E.A. Essock, J.K. DeFord, B.C. Hansen, M.J. Sinai, Oblique stimuli are seen best (not worst!) broad-band stimuli: a horizontal effect, Vision Res. 43 (2003) 1329-1335] reported a psychological 'horizontal effect', in which visual stimuli dominated by oblique orientations were best perceived by human subjects when tested with unique natural broad-band stimuli. In this study, using optical imaging and the similar visual stimuli, we found an overrepresentation of cardinal orientations, i.e. the neural oblique effect, but not 'horizontal effect', in area 17 of the cat. In addition, the oblique effect was abolished by GABA administration in area 21a due to the preferred orientation shifting (6.0%) and decrease of orientation selectivity strength of neurons (26.9%) in area 17. These results indicate a neuronal basis of the oblique effect when animals watch a more natural scene, whereas no evidence was found for the 'horizontal effect'.

PMID: 18420348 [PubMed - indexed for MEDLINE]

Successful prevalidation of the slug mucosal irritation test to assess the eye irritation potency of chemicals.

Laboratory of Pharmaceutical Technology, Ghent University, Harelbekestraat 72, B-9000 Gent, Belgium. els.adriaens@UGent.be

A previous 'in house' validation study showed that the SMI assay can be used as an alternative to the in vivo Draize eye irritation test. The aim of this multi-centre study with four participating laboratories was to assess the transferability and inter-laboratory variability of the assay using 20 reference chemicals covering the whole irritancy range. The eye irritation potency of the chemicals was assessed by measuring the amount of mucus produced during a 60-min contact period with a 1% dilution, and a second 60-min treatment with a 3.5% dilution. After each contact period the protein release from the mucosal surface was measured. Linear discriminant equations were used to convert the results into the corresponding EU eye irritation categories (NI, R36 and R41). All the non-irritants were predicted correctly by the four laboratories resulting in a 100% specificity. For the R36 compounds a correct classification rate of 89% (VITO) and 100% (SPL, JNJ and UGent) was obtained. The R41 compounds were classified correctly in 78% of the cases for VITO, 89% for SPL and JNJ and 100% for UGent. We can conclude that the SMI assay is a relevant, easily transferable and reproducible alternative to predict the eye irritation potency of chemicals.

PMID: 18406103 [PubMed - indexed for MEDLINE]

Comment in:

Lancet Oncol. 2008 May;9(5):406-7.

Prognostic significance of maximum tumour (bulk) diameter in young patients with good-prognosis diffuse large-B-cell lymphoma treated with CHOP-like chemotherapy with or without rituximab: an exploratory analysis of the MabThera International Trial Group (MInT) study.

Saarland University Medical School, Homburg, Germany.

BACKGROUND: The definition and role of bulky disease in young patients (ie, aged 18-60 years) with good-prognosis diffuse large-B-cell lymphoma (DLBCL), who have been treated with CHOP (cyclophosphamide, doxorubicin, vincristine, and prednisolone)-like chemotherapy with or without rituximab, remain controversial. We aimed to assess the effect of maximum tumour diameter (MTD) in these patients. METHODS: Patients from the MInT (Mabthera International Trial Group) study were eligible. We analysed event-free (EFS) and overall survival (OS) after CHOP-like chemotherapy with or without rituximab, according to MTD, by Martingale residual analyses and Cox regression models. Radiotherapy was given to sites of primary bulky disease according to national standards, and to primary extranodal disease at physician discretion. The primary endpoint was EFS and the secondary endpoint was OS. Analyses were by intention to treat. FINDINGS: Of the 824 patients enrolled in the MInT study, the informed-consent form of one patient was missing, leaving 823 patients evaluable for intention-to-treat analysis. Data on MTD of involved sites were available for 802 patients. Martingale residual analysis showed an adverse prognostic effect of MTD on EFS and OS, which increased linearly. In a multivariable analysis with MTD as a linear regression variable, the effect of MTD was significant after CHOP-like treatment alone for EFS (hazard ratio 1.090 [95% CI 1.051-1.130], p < 0.0001) and OS (1.119 [1.057-1.184], p = 0.0001), and after CHOP-like treatment and rituximab for OS (1.089 [1.003-1.183], p = 0.043), but not for EFS (1.044 [0.991-1.099], p=0.103). For CHOP-like treatment alone, 3-year EFS ranged from 78.2% (MTD < 5.0 cm, 95% CI 68.3-85.4) to 41.3% (MTD > or = 10.0 cm, 31.8-50.4). For CHOP-like treatment and rituximab, 3-year EFS ranged from 83.2% (MTD < 5.0 cm, 72.8-89.9) to 72.7% (MTD > or = 10.0 cm, 63.8-79.7). With CHOP-like treatment alone, 3-year OS decreased from 92.9% (MTD < 5.0 cm, 84.9-96.8) to 73.5% (MTD > or = 10.0 cm, 63.9-81.0); for CHOP-like treatment and rituximab, 3-year OS decreased from 98.0% (MTD < 5.0 cm, 92.2-99.5) to 85.2% (MTD > or = 10.0 cm, 77.0-90.6). For CHOP-like treatment, any cut-off point between 5.0 cm and 10.0 cm separated two populations with a significant EFS difference (p < 0.0001 for all log-rank tests) and OS difference (p < or = 0.003 for all log-rank tests). For CHOP-like treatment and rituximab, only a cut-off point of 10.0 cm separated two populations with a significant EFS difference (log-rank p = 0.047), but any cut-off point of 6.0 cm or more separated two populations with a significant OS difference (log-rank p values 0.0009-0.037). INTERPRETATION: Rituximab decreased, but did not eliminate the adverse prognostic effect of MTD in young patients with good-prognosis DLBCL. Due to the linear prognostic effect of MTD on outcome, arbitrary cut-off points for bulky disease can be set between 5.0 cm and 10.0 cm, depending on clinical considerations. Based on this study, a cut-off point of 10.0 cm might be a suitable margin in the rituximab era to delineate those patients with bulky disease.

PMID: 18400558 [PubMed - indexed for MEDLINE]

[Future elderly will be one of the greatest challenges. The Danish Geriatric Society]

Geriatrisk/Reumatologisk Afdeling B, Glostrup Hospital, DK-2600 Glostrup. kida@glo.regionh.dk

PMID: 18397643 [PubMed - indexed for MEDLINE]

Reversal of a distractor effect on saccade target selection after superior colliculus inactivation.

The Smith-Kettlewell Eye Research Institute, 2318 Fillmore Street, San Francisco, CA 94115, USA. rmm@ski.org

Recent evidence indicates that inactivation of the primate superior colliculus (SC) results in an increase in saccade target-selection errors. The pattern of errors suggests that a winner-take-all competition selects the saccade goal and that SC inactivation perturbs this process by biasing the competition against stimuli in the inactivated field. To investigate this idea, the difficulty of target selection was manipulated in a color-oddity search task by varying the number of homogeneous distractors in the search array. Previous studies have shown that target selection is easier when a greater number of homogeneous distractors is present, due to perceptual grouping of the distractors. These results were replicated when testing with the SC intact. Surprisingly, during SC inactivation, this normal trend was reversed: target-selection performance declined significantly with more distractors, resulting in a greater proportion of errant saccades to distractors. Examination of the saccade endpoints indicates that after SC inactivation, many errant saccades were directed to distractors adjacent to the target. This pattern of results suggests that the salience signal used by the SC for target selection is relatively broad in spatial scope. As a result, when the area of the SC representing the target location is inactivated, distractors near the target are at a competitive advantage relative to more distant distractors and, consequently, are selected more often as the saccade goal. This contributes to the trend of worse performance with more distractors due to the greater proximity of distractors to the target.

PMID: 18367699 [PubMed - indexed for MEDLINE]

PMCID: PMC2409266

ALT and viral load decline during PEG-IFN alpha-2b treatment for HBeAg-positive chronic hepatitis B.

Department of Gastroenterology and Hepatology, Erasmus MC, University Medical Centre Rotterdam, Rotterdam, The Netherlands.

BACKGROUND: Alanine aminotransferase (ALT) is one of the main indicators for inflammatory activity in chronic hepatitis B. During interferon-based therapy, approximately 25%-40% of patients exhibit an ALT flare. OBJECTIVES AND STUDY DESIGN: To analyze the relation between ALT and HBV-DNA during pegylated interferon alpha-2b (PEG-IFN) treatment and compare different patterns of on-treatment viral load decline with the occurrence of ALT flares. RESULTS: Of the 123 patients included in this study 31 (25%) exhibited an ALT flare during treatment or follow-up. Six out of 8 (75%) host-induced flares, i.e. ALT flares which were followed by a HBV-DNA decrease associated with a favorable treatment outcome, occurred in patients with a delayed HBV-DNA decline pattern (delayed vs. non-delayed decline, p=.022); 5 of these 8 patients exhibited HBeAg loss and 4 even HBsAg loss at the end of follow-up. The prediction of ALT normalization was possible using on-treatment viral load. Based on the difference from baseline, the evolution of viral load and ALT level were strongly interrelated during treatment and follow-up. With a joint model we estimated a correlation coefficient of 0.38 (p<0.001) during the first 4 weeks of the treatment and of 0.72 (p<0.0001) thereafter. CONCLUSION: There was a strong relation between ALT and viral load in HBeAg-positive chronic hepatitis B patients treated with PEG-IFN alpha-2b, especially after 4 weeks of treatment. Patients with a delayed decline in viral load often exhibited a host-induced flare associated with a favorable outcome.

PMID: 18359663 [PubMed - indexed for MEDLINE]

Constitutive equation for polymer networks with phonon fluctuations.

Center for Fluid Dynamics at DTU, Technical University of Denmark, DK-2800 Kgs. Lyngby, Denmark.

Recent research by Xing [Phys. Rev. Lett. 98, 075502 (2007)] has provided an expression for the Helmholtz free energy related to phonon fluctuations in polymer networks. We extend this result by constructing the corresponding nonlinear constitutive equation, usable for entirely general, volume conserving deformation fields. Constitutive equations for the sliplink model and the tube model are derived and the three models are examined by comparison with each other and with data from Xu and Mark [Rubber Chem. Technol. 63, 276 (1990)] and Wang and Mark [J. Polym. Sci., Part B: Polym. Phys. 30, 801 (1992)]. Elastic moduli are derived for the three models and compared with the moduli determined from the chemical stoichiometry. We conclude that the sliplink model and the phonon fluctuation model are relatively consistent with each other and with the data. The tube model seems consistent neither with the other models nor with the data.

PMID: 18351868 [PubMed]

Muscle activation during selected strength exercises in women with chronic neck muscle pain.

Lersø Parkalle 105, DK 2100 Copenhagen, Denmark. LLA@NRCWE.DK

BACKGROUND AND PURPOSE: Muscle-specific strength training has previously been shown to be effective in the rehabilitation of chronic neck muscle pain in women. The aim of this study was to determine the level of activation of the neck and shoulder muscles using surface electromyography (EMG) during selected strengthening exercises in women undergoing rehabilitation for chronic neck muscle pain (defined as a clinical diagnosis of trapezius myalgia). SUBJECTS: The subjects were 12 female workers (age=30-60 years) with a clinical diagnosis of trapezius myalgia and a mean baseline pain intensity of 5.6 (range=3-8) on a scale of 0 to 9. METHOD: Electromyographic activity in the trapezius and deltoid muscles was measured during the exercises (lateral raises, upright rows, shrugs, one-arm rows, and reverse flys) and normalized to EMG activity recorded during a maximal voluntary static contraction (MVC). RESULTS: For most exercises, the level of muscle activation was relatively high (>60% of MVC), highlighting the effectiveness and specificity of the respective exercises. For the trapezius muscle, the highest level of muscle activation was found during the shrug (102+/-11% of MVC), lateral raise (97+/-6% of MVC), and upright row (85+/-5% of MVC) exercises, but the latter 2 exercises required smaller training loads (3-10 kg) compared with the shrug exercise (20-30 kg). DISCUSSION AND CONCLUSION: The lateral raise and upright row may be suitable alternatives to shrugs during rehabilitation of chronic neck muscle pain. Several of the strength exercises had high activation of neck and shoulder muscles in women with chronic neck pain. These exercises can be used equally in the attempt to achieve a beneficial treatment effect on chronic neck muscle pain.

PMID: 18339796 [PubMed - indexed for MEDLINE]

Antimicrobial activities of twenty lysine-peptoid hybrids against clinically relevant bacteria and fungi.

Department of Natural Sciences, Faculty of Life Sciences, University of Copenhagen, Copenhagen, Denmark.

BACKGROUNd: This paper describes the antimicrobial activities of 20 lysine-peptoid hybrids against a selection of clinically relevant bacteria and fungi. METHODS: Minimal inhibitory concentrations were determined against methicillin-susceptible Staphylococcus aureus (ATCC 29213), methicillin-resistant S. aureus (ATCC 33591), vancomycin-intermediate S. aureus (ATCC 700699 MU50), vancomycin-resistant Enterococcus faecium (ATCC 700221), Pseudomonas aeruginosa (ATCC 27853), Salmonella typhimurium (clinical isolate), Klebsiella pneumoniae (clinical isolate), amphotericin-B-resistant C. albicans (ATCC 200955) and Cryptococcus neoformans (clinical isolate). RESULTS: The lysine-peptoid hybrids proved to be active against all strains tested, except K. pneumoniae. For each susceptible strain, we identified at least 4 lysine-peptoid hybrids showing excellent activity. The most active compounds displayed minimal inhibitory concentrations ranging from < or =1.6 to 6.25 microM. CONCLUSION: This study demonstrates that lysine-peptoid hybrids show activity against drug-resistant pathogens.

PMID: 18332629 [PubMed - indexed for MEDLINE]