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Biomedical subjects

S S Ashraf

Publications and source records attributed to S S Ashraf.

24 records · Page 2Linked to original sources

Type I aortic dissection in a patient with osteogenesis imperfecta.

The previously undescribed association between aortic dissection and osteogenesis imperfecta is reported in a 39-year-old man with known osteogenesis imperfecta, who presented with a type I aortic dissection. His ascending aorta was repaired using a Dacron tube graft under hypothermic circulatory arrest but the patient died 12 h later, following re-dissection around the left coronary ostium resulting in massive myocardial infarction of the left ventricle.

Adult↗

Identification of an abundant S-thiolated rat liver protein as carbonic anhydrase III; characterization of S-thiolation and dethiolation reactions.

An S-thiolated 30-kDa protein has been purified from rat liver by two steps of ion-exchange chromatography. This monomeric protein has two "reactive" sulfhydryls that can be S-thiolated by glutathione (form a mixed disulfide with glutathione) in intact liver. The protein has been identified as carbonic anhydrase III by sequence analysis of tryptic peptides from the pure protein. The two "reactive" sulfhydryls on this protein can produce three different S-thiolated forms of the protein that can be separated by isoelectric focusing. Using this technique it was possible to study the S-thiolation and dethiolation reactions of the pure protein. The reduced form of this protein was S-thiolated both by thiol-disulfide exchange with glutathione disulfide and by oxyradical-initiated S-thiolation with reduced glutathione. The S-thiolation rate of this 30-kDa protein was somewhat slower than that of glycogen phosphorylase b by both S-thiolation mechanisms. The S-thiolated form of this protein was poorly dethiolated (i.e., reduced) by glutathione, cysteine, cysteamine, or coenzyme A alone. Enzymatic catalysis by two different enzymes (glutaredoxin and thioredoxin-like) greatly enhanced the dethiolation rate. These experiments suggest that carbonic anhydrase III is a major participant in the liver response to oxidative stress, and that the protein may be S-thiolated by two different non-enzymatic mechanisms and dethiolated by enzymatic reactions in intact cells. Thus, the S-thiolation/dethiolation of carbonic anhydrase III resembles glycogen phosphorylase and not creatine kinase.

Amino Acid Sequence↗

Hemoperitoneum following rupture of ectopic varix along splenorenal ligament in extrahepatic portal vein obstruction.

A 29-year-old man with extrahepatic portal vein obstruction who underwent variceal eradication by sclerotherapy six years ago, was admitted with hypotension and abdominal pain. Abdominal paracentesis yielded frank blood. Laparotomy showed bleeding from a large ectopic vessel along the splenorenal ligament. The vessel was ligated and the patient recovered.

Adult↗