DETERMINATION OF WARMS ISCHEMIA TIME AT DONOR NEPHRECTOMY1

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Abstract
To assess the warm ischemia time of kidneys with obscure donor histories we attempted to develop an index for the duration of ischemia by analysis of adenine nucleotides and their degradation products in cortical hiopsies of canine kidneys. Two biopsy harvesting techniques were compard. The use of a laboratory technique (dentist's drill) resulted in higher concentrations of adenosine triphosphate (ATP) in normoxic tissue specimens as copared with a clinical method of harvesting biopsies (wedge biopsy). However the sum of adenine nucleotides (AN) (ATP, adenosine diphosphate [ATP, adenosine diphosphate [ATP], adenosine monophosphate [AMP]) was not significantly different in both groups (P<0.05). Therefore, wedge biopsies were used to study the dgeradation of AN following 0,30,60,90, and 120 min of ischemia. Adenine nucleotides and their degradation products were assayed by high-performance liquid chromatography. Concentrations of individual adenine nucleotides did not show a consistent correlation with warm ischemia time. However, as the sum of the AN and the sum of their degradation products (DP) decreases and increased, respectively, the balance between these metabolites offered a good correlation with duration of warm ischemia. The ration of DP to AN was significantly different at each interval (P<0.05). To study the influence of temperature on the degradation process, ischemia was induced at 37dGC and 32dG. Lowering of the temperature reduced the catabolic rate of the AN. The ratio of DP to AN was significantly different from corresponding values at 37dGC. In biopsies of nonischemic human donor kidneys, concentrations of adenine nucleotides and their degradation products were measured. Biopsies weighing lessthan 0.01% of total renal mass were large enough to meet analytical demands. The ratio of DP to AN in human kidney biopsies was in the same range as in the corresponding dog kidney biopsies. These findings demonstrate that the ratio of DP to AN, as determined from concentrations of purine metabolites in canine cortical wedge biopsies, is a sensitive and potentially useful index of warm ischemia time.