Measure of oxidative stress were studied in blood samples from 10 pati
ents undergoing bloodless lower limb surgery. Ischaemia induced a sign
ificant increase in plasma hypoxanthine concentration and xanthine oxi
dase activity both in the operated leg and in the systemic circulation
. Five minutes after reperfusion. ratio of xanthine oxidase/total xant
hine oxidase and dehydrogenase activities rose moderately, whereas at
20 min xanthine oxidase accounted for all xanthine oxido-reductase act
ivity in the systemic circulation. A significant increase in blood glu
tathione redox ratio, enhanced oxidation of haemoglobin to methaemoglo
bin and rise in plasma haemoglobin concentration were present only in
the operated limb. Thus, although the level of the potential free radi
cal generators ruse significantly both locally and in the systemic cir
culation, oxidative stress, as indicated by blood glutathione and eryt
hrocyte injuries, remained limited to the reperfused leg.