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Molecular Imaging and Contrast Agent Database (MICAD) [Internet]. Bethesda (MD): National Center for Biotechnology Information (US); 2004-2013.

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Molecular Imaging and Contrast Agent Database (MICAD) [Internet].

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99mTc-Labeled S-benzoylmercaptoacetyl triglycine d-galactose

[99mTc]SBz-MAG3-Ga
, PhD
National Center for Biotechnology Information, NLM, NIH, Bethesda, MD 20894

Created: ; Last Update: May 11, 2010.

Chemical name:99mTc-Labeled S-benzoylmercaptoacetyl triglycine d-galactose
image 92764909 in the ncbi pubchem database
Abbreviated name:[99mTc]SBz-MAG3-Ga
Synonym:[99mTc]MAG3-Ga
Agent Category:Compound
Target:Lectins
Target Category:Proteins
Method of detection:Single-photon emission computed tomography (SPECT); gamma planar imaging
Source of signal / contrast:99mTc
Activation:No
Studies:
  • Checkbox In vitro
  • Checkbox Rodents
Structure of [99mTc]SBz-MAG3-Ga.
Click on the above structure for additional information in PubChem.

Background

[PubMed]

Lectins are proteins that bind carbohydrates reversibly and are present on the membrane surface of all prokaryotic and eukaryotic cells. It is known that the carbohydrate–lectin interactions result in the initiation of a fight against or the development of a variety of conditions such as cancer metastases (1), pathological inflammation (2), and microbial infections (3). Several clinical trials approved by the United States Food and Drug Administration are under way to evaluate the use of lectins to treat a variety of infections and cancerous tumors. Because of their role in the modulation of diverse physiological processes and diseases, investigators are increasingly interested in studying lectins for the development (4) and delivery of therapeutic drugs in humans (5). Although lectin glycoarrays have been used to profile different glycoproteins (6), no agents are presently available to investigate the function of the lectin-carbohydrate complexes under in vivo conditions. In an effort to develop imaging agents for the in vivo study of lectins, de Barros et al. (7) synthesized glucose (Gl), N-acetylglucosamine (NG), and galactose (Ga) respectively conjugated to S-benzoylmercaptoacetyl triglycine (SBz-MAG3) and labeled these compounds with 99mTc to obtain [99mTc]SBz-MAG3-Ga (or [99mTc]MAG3-Ga), [99mTc]SBz-MAG3-Gl (or [99mTc]MAG3-Gl), and [99mTc]SBz-MAG3-NG (or [99mTc]MAG3-NG). The biodistribution of these radiolabeled carbohydrates was then studied in normal Swiss mice (7). This chapter describes the results obtained with [99mTc]SBz-MAG3-Ga. Results obtained with [99mTc]SBzMAG3-Gl (8) and [99mTc]SBzMAG3-NG (9) are presented in separate chapters in MICAD (www.micad.nih.gov).

Synthesis

[PubMed]

The synthesis of [99mTc]SBzMAG3-Ga was described by de Barros et al. (7). The radiochemical purity of the tracer was reported to be >90%. The radiochemical yield, specific activity, and stability of [99mTc]SBzMAG3-Ga were not reported.

In Vitro Studies: Testing in Cells and Tissues

[PubMed]

No references are currently available.

Animal Studies

Rodents

[PubMed]

The biodistribution of [99mTc]SBzMAG3-Ga was studied in normal Swiss mice (7). The animals (n = 5 mice per time point) were injected with the radiochemical, and the mice were euthanized at various time points from 5 to 60 min post-injection (p.i.) to collect all major organs and to determine the accumulated radioactivity. At 5 min p.i., maximum accumulation of label was in the bladder (44.86 ± 6.98% injected dose per gram tissue (% ID/g)), followed by the liver (11.99 ± 1.00% ID/g), kidneys (9.11 ± 2.17% ID/g), blood (4.12 ± 0.67% ID/g), and lungs (2.11 ± 0.20% ID/g). At 60 min p.i., the bladder had the highest amount of radioactivity (86.37 ± 5.06% ID/g), followed by liver (6.95 ± 0.64% ID/g), kidneys (2.47 ± 0.38% ID/g), lungs (0.91 ± 0.08% ID/g), and blood (0.86 ± 0.07% ID/g). This study indicated that radioactivity either as [99mTc]SBzMAG3-Ga or a metabolite was excreted primarily through the urinary route. The radioactivity uptake pattern with [99mTc]SBzMAG3-Ga was similar to that observed with [99mTc]SBzMAG3-Gl (8) and [99mTc]SBzMAG3-NG (9). However, accumulation of [99mTc]SBz-MAG3-Ga was significantly (P < 0.05) higher in the liver at both 5 min and 60 min p.i. than accumulation of either [99mTc]SBzMAG3-Gl (8.77 ± 1.22% ID/g at 5 min and 1.82 ± 0.15% ID/g at 60 min p.i.) or [99mTc]SBzMAG3-NG (9.58 ± 0.81% ID/g at 5 min and 1.88 ± 0.44% ID/g at 60 min p.i.).

In another study, [99mTc]SBzMAG3-Ga was injected into normal mice in the presence of 10-fold excess unlabeled Ga, and the animals were euthanized (n = 5 mice per time point) as before to determine the amount of radioactivity accumulated in the various organs (7). The biodistribution pattern of the label in the various organs was essentially as described above, but a lower amount of radioactivity was observed to accumulate in the liver, kidney, and blood (2.43 ± 0.13, 1.88 ± 0.16, and 0.53 ± 0.03% ID/g, respectively) at 60 min p.i.

From these studies, the investigators concluded that [99mTc]SBzMAG3-Gl was selectively taken up by the liver and appeared to be a suitable for the imaging of this organ to evaluate hepatic function in rodents (7).

Other Non-Primate Mammals

[PubMed]

No references are currently available.

Non-Human Primates

[PubMed]

No references are currently available.

Human Studies

[PubMed]

No references are currently available.

Supplemental Information

[Disclaimers]

No information is currently available.

References

1.
Makrilia N., Kollias A., Manolopoulos L., Syrigos K. Cell adhesion molecules: role and clinical significance in cancer. Cancer Invest. 2009;27(10):1023–37. [PubMed: 19909018]
2.
Yang R.Y., Rabinovich G.A., Liu F.T. Galectins: structure, function and therapeutic potential. Expert Rev Mol Med. 2008;10:e17. [PubMed: 18549522]
3.
Haagsman H.P., Hogenkamp A., van Eijk M., Veldhuizen E.J. Surfactant collectins and innate immunity. Neonatology. 2008;93(4):288–94. [PubMed: 18525212]
4.
Ernst B., Magnani J.L. From carbohydrate leads to glycomimetic drugs. Nat Rev Drug Discov. 2009;8(8):661–77. [PubMed: 19629075]
5.
Darbre T., Reymond J.L. Glycopeptide dendrimers for biomedical applications. Curr Top Med Chem. 2008;8(14):1286–93. [PubMed: 18855709]
6.
Zhao J., Patwa T.H., Qiu W., Shedden K., Hinderer R., Misek D.E., Anderson M.A., Simeone D.M., Lubman D.M. Glycoprotein microarrays with multi-lectin detection: unique lectin binding patterns as a tool for classifying normal, chronic pancreatitis and pancreatic cancer sera. J Proteome Res. 2007;6(5):1864–74. [PubMed: 17428079]
7.
de Barros A.L., Cardoso V.N., Mota L.D., Alves R.J. Synthesis and biodistribution studies of carbohydrate derivatives radiolabeled with technetium-99m. Bioorg Med Chem Lett. 2010;20(1):315–317. [PubMed: 19926278]
8.
Chopra, A., 99mTc-Labeled S-benzoylmercaptoacetyl triglycine D-glucose. Molecular Imaging and Contrast agent Database (MICAD) [database online]. National Library of Medicine, NCBI, Bethesda, MD, USA. Available from www​.micad.nih.gov, 2004 -to current.
9.
Chopra, A., 99mTc-Labeled S-benzoylmercaptoacetyl triglycine N-acetylglucoseamine. Molecular Imaging and Contrast agent Database (MICAD) [database online]. National Library of Medicine, NCBI, Bethesda, MD, USA. Available from www​.micad.nih.gov, 2004 -to current.

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