Oxidative stress plays an important role in the progression of vascular endothelial dysfunction. The two major systems generating vascular oxidative stress are the NADPH oxidase and the xanthine oxidase pathways. Allopurinol, a xanthine oxidase inhibitor, has been in clinical use for over 40 years in the treatment of chronic gout. Allopurinol has also been shown to improve endothelial dysfuncti...

Heart failure is a clinical syndrome associated with elevated levels of oxygen-derived free radicals. Xanthine oxidase activity is believed to be one source of reactive oxygen species in the failing heart. Interventions designed to reduce oxidative stress are believed to have significant therapeutic potential in heart failure. This study tested the hypothesis that xanthine oxidase activity woul...

To examine the possible role of reactive oxygen metabolites in lymphocyte-mediated cytolysis, the morphology of cell death following the exposure of cells to reactive oxygen metabolites in vitro was compared with the morphology of cell-mediated killing in vitro of tumour cells by natural killer (NK) cells. Ultrastructural examination of human tumour cells that were dying following incubation fo...

Vascular smooth muscle cells (VSMCs) proliferate in response to arterial injury. Recent findings suggest that, in addition to platelet-derived growth factors, growth factors from inflammatory cells and endothelial cells at the site of injury may contribute to VSMC proliferation. We hypothesized that a common mechanism by which endothelial cells and inflammatory cells stimulate VSMC growth could...

Recently it has been observed that liver enzyme activity may be markedly affected by dietary conditions. Seifter et al. (1) have demonstrated that during complete dietary protein deprivation loss of arginase and n-amino acid oxidase from rat liver occurs more rapidly than loss of general liver protein. We (2) have observed that the level of xanthine oxidase activity in rat liver may be altered ...

Treatment of milk xanthine oxidase and chicken liver xanthine dehydrogenase with high concentrations of salts for several hours resulted in the loss of reactivity toward O2 and NAD, respectively. Oxidation of xanthine by either enzyme in the presence of electron acceptors such as dichlorophenol indophenol was unimpaired under these conditions, in the presence of 3 M KI. Prolonged treatment of x...

In this study, the antioxidant properties of 80 % ethanol extracts of 16 species of plants from Jeju Island in Korea were evaluated using various antioxidant assays, including the DPPH (1,1-Diphenyl-2-pricrylhydrazyl) radical scavenging, superoxide scavenging, xanthine oxidase inhibition and hydrogen peroxide scavenging activities. Among the 16 plant extracts tested, CN-13 showed strong antioxi...