Samples from four human hearts were analyzed for both their xanthine dehydrogenase and xanthine oxidase content. We used the conventional spectrophotometric assay and a more sensitive fluorometric assay to determine the content of enzyme in these samples. In no case could any activity be detected. We conclude that human hearts must contain less than 2.0 nU/g of activity. This makes it unlikely that xanthine oxidase is a significant source of O2 free radicals in the ischemic human heart or that xanthine oxidase inhibitors will be of therapeutic value in that setting.
The present study was designed to evaluate the ability of allopurinol to limit infarct size following permanent coronary occlusion in the greyhound. Coronary occlusion was produced by injecting 2.5 mm plastic beads into the coronary artery of the closed chest dog. Non-perfused myocardium, the area at risk, was visualised by autoradiography of 141Cerium labelled microspheres which were infused immediately following coronary embolization. The treated dogs (n = 12) received 400 mg of allopurinol orally one day before surgery. A 25 mg . kg-1 bolus was administered (iv) immediately before occlusion, and repeated every 8 h. 11 dogs served as controls. After 24 h, the dogs were killed and the hearts were sliced into 5.0 mm transverse sections. The infarcted myocardium was visualised by triphenyl tetrazolium chloride staining. The percentage of the risk zone which evolved to infarct was calculated. This percentage was 18.1 +/- 3.95% in the allopurinol group vs 58.4 +/- 2.81% in the control group (p less than 0.001). We conclude that allopurinol is a potent drug for the limitation of infarct size in the dog with permanent coronary occlusion.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.