Identification of xanthine oxidase activity following reperfusion in human

---

tissue. Wilkins EG. Rees RS. Smith D. Cashmer B. Punch J. Till GO. Smith DJ Jr. Annals of Plastic Surgery. [JC:5vb] 31(1):60-5, 1993 Jul. In this series of experiments, we surveyed xanthine oxidase activity after microvascular transfer in the venous effluent after reperfusion of human rectus abdominis muscle (n = 8) and jejunum (n = 4). Enzyme activity was correlated with duration of ischemia and biochemical markers of cellular injury. Xanthine oxidase (XO) activity was measured spectrofluorometrically using a pterin assay, whereas cellular injury was measured with commercial creatinine phosphokinase activity assay and lipid peroxidation products using a spectrophotometer. The data demonstrated that XO activity was statistically significantly increased in muscle flaps kept at room temperature during ischemia compared with muscle flaps that were cooled (p : 0.05). Creatinine phosphokinase activity was also increased after 15 minutes of reperfusion in muscle flaps that were not cooled (p : 0.05). Two of the jejunal free flaps had ischemia times of : 1 hour and had elevated XO activity after reperfusion despite cooling (p : 0.05). Two other jejunal flaps had ischemia times of : 1 hour, but in one case, the XO activity was increased before harvest. The other case had no increase in XO activity.