allopurinol and Embolism

Topics: Adenosine; Allopurinol; Animals; Embolism; Glutathione; Heart; Insulin; Malondialdehyde; Myocardial Contraction; Myocardial Reperfusion; Myocardium; Organ Preservation; Organ Preservation Solutions; Raffinose; Swine

Oxygen-derived free radicals are thought to injure the ischemic heart during coronary microvascular embolization.. To test this idea, microspheres (15 microns in diameter) were repetitively administered into the left anterior descending coronary artery to cause microvascular embolization in dogs. Myocardial contractile and metabolic dysfunctions were significantly attenuated after treatments with recombinant human superoxide dismutase, an acyl derivative of ascorbic acid (CV3611, 2-O-octadecylascorbic acid), and xanthine oxidase inhibitor (allopurinol). The free radical scavengers and inhibitor enhanced the coronary hyperemic flow response during embolization, and the total number of microspheres causing maximal embolization was increased by these drugs. When 8-phenyltheophylline was additionally administered with superoxide dismutase, these beneficial effects were abolished, indicating that coronary effects of these drugs may be due to increased release of adenosine during coronary microvascular embolization.. We conclude that oxygen radicals worsen the ischemic injury in coronary microembolization.

Topics: Allopurinol; Animals; Ascorbic Acid; Body Water; Cardiomyopathies; Coronary Disease; Dogs; Edema; Embolism; Free Radical Scavengers; Free Radicals; Microcirculation; Microspheres; Oxygen; Superoxide Dismutase; Theophylline

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.

Topics: Allopurinol; Animals; Coronary Vessels; Disease Models, Animal; Dogs; Embolism; Female; Male; Myocardial Infarction; Myocardium; Oxypurinol; Xanthine Oxidase