The world's first wiki where authorship really matters (Nature Genetics, 2008). Due credit and reputation for authors. Imagine a global collaborative knowledge base for original thoughts. Search thousands of articles and collaborate with scientists around the globe.

wikigene or wiki gene protein drug chemical gene disease author authorship tracking collaborative publishing evolutionary knowledge reputation system wiki2.0 global collaboration genes proteins drugs chemicals diseases compound
Hoffmann, R. A wiki for the life sciences where authorship matters. Nature Genetics (2008)
 
 
 
 
 

2,2',4,4',5,5'-hexachlorobiphenyl as a 2,3,7,8-tetrachlorodibenzo-p-dioxin antagonist in C57BL/6J mice.

At doses as high as 750 to 1000 mumol/kg, 2,2',4,4',5,5'-hexachlorobiphenyl (HCBP) did not cause fetal cleft palate, suppress the splenic plaque-forming cell response to sheep red blood cells, or induce hepatic microsomal ethoxyresorufin O-deethylase (EROD) in C57BL/6J mice. Despite the lack of activity of HCBP in eliciting any of these aryl hydrocarbon ( Ah) receptor-mediated responses, competitive binding studies indicated that HCBP competitively displaced 2,3,7,8-[3H]tetrachlorodibenzo-p-dioxin (TCDD) from the murine hepatic cytosolic receptor. Cotreatment of C57BL/6J mice with TCDD (3.7 nmol/kg) and HCBP or 4,4'-diiodo-2,2',5,5'-tetrachlorobiphenyl (I2-TCBP) (400 or 1000 mumol/kg) showed that both compounds partially antagonized TCDD-mediated cleft palate and immunotoxicity (i.e., suppression of the splenic plaque-forming cell response to sheep red blood cells), and HCBP antagonized TCDD-mediated hepatic microsomal EROD induction. Thus, HCBP and I2-TCBP, like the commercial polychlorinated biphenyl mixture Aroclor 1254, were partial antagonists of TCDD action in C57BL/6J mice; however, it was also apparent from the results that Aroclor 1254 was the more effective antagonist at lower doses. Using [3H]TCDD, it was also shown that some of the effects of HCBP on TCDD-mediated cleft palate may be due to the decreased levels of TCDD found in the fetal palates after cotreatment with TCDD and HCBP. 4,4'-[125I2]diiodo-2,2',5,5'-tetrachlorobiphenyl ([125I2]TCBP) of high specific activity (3350 Ci/mmol) was synthesized and used to investigate the direct binding of this compound to the murine hepatic Ah receptor or other cytosolic proteins. No direct specific binding was observed between 125I2-TCBP and any cytosolic proteins using a sucrose density gradient assay procedure. These results contrasted with previous studies with Aroclor 1254 that suggested that this mixture acted as a competitive Ah receptor antagonist.[1]

References

  1. 2,2',4,4',5,5'-hexachlorobiphenyl as a 2,3,7,8-tetrachlorodibenzo-p-dioxin antagonist in C57BL/6J mice. Biegel, L., Harris, M., Davis, D., Rosengren, R., Safe, L., Safe, S. Toxicol. Appl. Pharmacol. (1989) [Pubmed]
 
WikiGenes - Universities