Arterial hypertension is associated with increased levels of reactive oxygen species, which may scavenge endothelium-derived NO and thereby diminish its vasorelaxant effects. However, the quantitatively relevant source of reactive oxygen species is unclear. Thus, this potential pathomechanism is not yet pharmacologically targetable. Several enzymatic sources of reactive oxygen species have been...

In 1948 Keith et al. (1) demonstrated that in chicks fed a folic aciddeficient diet liver xanthine oxidase activity was far higher than that observed in birds receiving adequate levels of folic acid. It was postulated (2, 3) that 6-formylpteridine, a potent inhibitor of xanthine oxidase in vitro, was biologically active in controlling the oxidation of xanthine and hypoxanthine in vivo, since 6-...

The twin character of reactive oxygen species is substantiated by a growing body of evidence that reactive oxygen species within cells act as inducers and accelerators of the oncogenic phenotype of cancer cells, while reactive oxygen species can also induce cancer cell death and can therefore function as anti-tumorigenic species. The aim of this study was to assess a possible influence of xanth...

In a previous study (1) it was shown that dogs maintained on a purified diet developed a defect in acetaldehyde metabolism. Of the five known enzyme systems that could theoretically be involved in acetaldehyde metabolism in viva (aldolase, mutase, carboxylase, aldehyde ox&se, and xanthine oxidase), the xanthine and aldehyde oxidases seemed most likely to be dependent upon a dietary factor not a...

Since ancient times, traditional medicines have been in the usage for the treatment of Diabetes mellitus. An edible fruit from traditional medicinal plant Capparis zeylanica (CZ) was studied for its anti diabetic, insulin secretagogue activities and mechanisms involved in it. In Streptozotocin induced diabetes rats, oral administration of Capparis zeylanica methanolic extract (CZME) (200 mg/kg ...

A current hypothesis states that tolerance to nitroglycerin (GTN) involves increased formation of superoxide (O2*-). Studies showing that inhibitors of protein kinase C (PKC) prevent tolerance to GTN suggest the involvement of PKC activation, which can also increase O2*-. We examined the roles of O2*-, peroxynitrite (ONOO-), and PKC activation in GTN tolerance. Pre-exposure of rat aortic rings ...

R eperfusion therapy for acute myocardial infarction reduces myocardial dysfunction and mortality. However, reperfusion can also injure myocardium,' and adjunctive agents have been sought to limit reperfusion injury. After laboratory reports of successful reduction in infarct size by superoxide dismutase (SOD) after ischemia and reperfusion,2-7 SOD became the first of these agents to be used in...

Various purine analogs active as carcinostatic agents have previously been shown to act as po tent inhibitors of xanthine oxidase in vitro in both homogenate and isolated enzyme systems (4, 5). 8-Azaguanine (8-AG) has been demonstrated to be an in vitro inhibitor of both xanthine oxidase and uricase (4, 9). Elion et al. have reported that 6mercaptopurine (6-MP) is a substrate for xanthine oxida...