Biomedical subjects

S Iu

Publications and source records attributed to S Iu.

At least 19 recordsLinked to original sources

PubMed1988

Adenine nucleotide tissue concentrations and liver allograft viability after cold preservation and warm ischemia.

The relation between adenine nucleotide liver concentrations and the viability of liver allografts after cold preservation and warm ischemia was studied. A rat model was used with storage times defined in terms of allograft viability. Livers were excised and stored for 4 hr at 4 degrees C or 1 hr at 37 degrees C (viable if transplanted) or for 8 hr at 4 degrees C or 2 hr at 37 degrees C (not viable if transplanted) in a solution containing 0.9% NaCl and 2 mM CaCl2. Adenine nucleotide, malondialdehyde, and glutathione concentrations were measured in liver biopsies at the end of the storage periods and in control livers. During cold preservation, ATP concentrations decline, but degradation is largely halted at AMP, and this is independent of the length of storage or viability of the allograft. Graft failure is not due to lack of availability of intramitochondrial substrate (AMP) for rephosphorylation to adenosine triphosphate (ATP), nor is it likely that provision of such substrate will be helpful. On the other hand, with warm ischemia, degradation to inosine, hypoxanthine and xanthine occurs and nonviable livers develop higher levels of xanthine than viable ones; in fact, xanthine concentrations provide 100% discrimination between viable and nonviable warm preserved livers. Malondialdehyde concentrations were also significantly greater in the warm preserved nonviable livers, indicating that some lipid peroxidation may occur even before reperfusion of allografts. Glutathione concentrations were similar in all experimental groups.

Adenine Nucleotides↗

PubMed1987

Markers of allograft viability in the rat. Relationship between transplantation viability and liver function in the isolated perfused liver.

The relationship between transplant viability and liver function has been examined. Wistar rat livers were preserved at 4 degrees C for increasing intervals and then transplanted into Wistar rat recipients. Two critical times were identified, the longest preservation period with 100% transplantation success (4 hr) and the shortest preservation period with 100% transplant failure (8 hr). The comparable critical times were also identified in livers preserved at 37 degrees C (1 hr and 2 hr). Liver functions were studied by the isolated perfused liver technique in other rat livers stored at 4 degrees C or 37 degrees C for the critical times. Two liver function tests, AST and LDH concentration in perfusate, discriminated between viable and nonviable livers across as well as within preservation groups. AST gave the best separation between viable and nonviable livers. Some functions such as ALT concentration in perfusate separated viable from non viable allografts only within preservation groups. Other liver functions were more sensitive to preservation temperature than allograft viability. Oxygen consumption after cold preservation for either critical time was about twice control levels. Urea production was far below control levels in warm-preserved livers but almost normal in cold-preserved livers. Our results indicate that AST release into perfusate can be used as a screening technique to optimize preservation methods, reserving transplantation for confirming the most promising results.

Animals↗

PubMed1987