BACKGROUND Increased inactivation of nitric oxide by superoxide (O2*-) contributes to endothelial dysfunction in patients with coronary disease (CAD). We therefore characterized the vascular activities of xanthine oxidase and NAD(P)H oxidase, 2 major O2*--producing enzyme systems, and their relationship with flow-dependent, endothelium-mediated vasodilation (FDD) in patients with CAD. METHODS...

Interferon, interferon inducers, and a variety of other immunomodulators are known to depress the hepatic cytochrome P-450 drug-metabolizing system. Two concepts have been proposed to explain this phenomenon. (a) The steady-state of cytochrome P-450 is altered through decreased synthesis and increased degradation of cytochrome P-450 apoprotein. (b) Interferon induces xanthine oxidase; superoxid...

The electron acceptor 2,6-dichlorophenolindophenol (DCI) forms a spectrophotometrically and kinetically detectable complex with bovine milk xanthine oxidase. The visible absorption spectrum of complexed DC1 exhibits an absorption maximum at 660 nm at pH 7.8 (E = 34.2 X lo3 M-’ cm-‘), a marked bathochromic shift from the visible absorption maximum at 608 nm characteristic of the free dye (E = 21...

A recent finding from this laboratory indicated that the incubation in vitro of purified xanthine oxidase with trace amounts of l-ascorbic acid resulted in a marked inhibition of the enzymatic activity (1, 2). Since the physiological mode’of action of Z-ascorbic acid is still obscure, it seemed desirable to determine whether ascorbic acid would, in the intact animal, exert a similar effect on x...

The endogenous reactive oxygen species ("ROS") formation is associated with many pathologic states such as inflammatory diseases, neurodegenerative diseases, brain and heart ischemic injuries, cancer, and aging. The purpose of this study was to investigate the endogenous sources for "ROS" formation in intact isolated rat hepatocytes, in particular, peroxisomal oxidases, monoamine oxidase, xanth...