BACKGROUND Impaired flow-dependent, endothelium-mediated vasodilation (FDD) in patients with chronic heart failure (CHF) results, at least in part, from accelerated degradation of nitric oxide by oxygen radicals. The mechanisms leading to increased vascular radical formation, however, remain unclear. Therefore, we determined endothelium-bound activities of extracellular superoxide dismutase (ec...

The Cover Feature illustrates xanthine oxidase converts to uric acid, passing electrons an osmium-modified polymer, which routes them efficiently the electrode surface. More information can be found in Research Article by P. Pinyou, V. Blay et al.

During the acute phase of myocardial ischemia, adenine nucleotides are degraded to nucleosides and bases, especially inosine and hypoxanthine. Simultaneously, xanthine dehydrogenase is converted to xanthine oxidase, an enzyme that converts hypoxanthine to xanthine, and xanthine to uric acid, producing a superoxide anion for each molecule of hypoxanthine or xanthine oxidized. To determine if fre...

The systematic study of the substrate specificity of mammalian xanthine oxidase has indicated a common mechanism by which various purines may be dehydrogenated (1). The results obtained also made it clear why methylated xanthines, with the exception of 1-methylxanthine (2), cannot be oxidized by xanthine oxidase to the corresponding substituted uric acids (3, 4). Therefore, another source had t...

Myocardial xanthine oxidase has been associated with reoxygenation injury induced by oxygen radicals. The damage due to myocardial ischemia and reperfusion increases with age; therefore, one would expect to find more xanthine oxidase in adult than in young hearts. Consequently, we studied the age-dependence of xanthine oxidoreductase activity in hearts, in addition to the localization of the en...

Oxidative stress is considered a central pathophysiological event in cardiovascular disease, including hypertension. Early age reduction in renal mass is associated with hypertension and oxidative stress in later life, which is aggravated by increased salt intake. The aim of the present study was to examine if renal sympathetic denervation can exert blood pressure lowering effects in uninephrec...

The behavior of the rate-limiting enzyme of purine catabolism, xanthine oxidase (EC 1.2.3.2); was examined in normal liver, in 17 hepatomas of different growth rates, and in rapidly growing differentiating and regenerating liver. Xanthine oxidase activity was measured in the supernatant fluid prepared by centrifugation of 5% homogenates at 100,000 X g for 30 min. There was no uricase activity ...

Molybdenum-containing enzymes, aldehyde oxidase and xanthine oxidase, are important in the oxidation of N-heterocyclic xenobiotics. However, the role of these enzymes in the oxidation of drug-derived aldehydes has not been established. The present investigation describes the interaction of eleven structurally related benzaldehydes with guinea pig liver aldehyde oxidase and bovine milk xanthine ...

This study was designed to study xanthine oxidase (XO) and xanthine dehydrogenase (XD) activity in the lung of rats exposed to prolonged restraining immobilization stress. Immobilization caused more than twofold increase of xanthine oxidase activity in the rat lung. The activity of xanthine oxidase decreased in lung homogenates incubated at -20 degrees C for 24 h. The same incubation of homogen...