BACKGROUND Cigarette smoking causes endothelial dysfunction, possibly through increased oxidant stress. The enzyme xanthine oxidase produces oxidative free radicals. We tested the hypothesis that xanthine oxidase contributes to endothelial dysfunction in cigarette smokers by administering the inhibitor allopurinol. METHODS AND RESULTS Fourteen cigarette smokers (31+/-4 pack years) and 14 age-...

In this study, centrifugal ultrafiltration coupled with high performance liquid chromatographymass spectrometry was utilized to screen and identify xanthine oxidase inhibitors from Puerariae flos extract. The experimental conditions of centrifugal ultrafiltration including xanthine oxidase concentration, incubation time, pH and temperature were optimized. At the optimum condition (xanthine oxid...

A study of the effect of diet on the concentration of xanthine dehydrogenase in chicken tissues was considered desirable for a number of reasons. Previous studies on the rat showed the dramatic way in which the dietary content of several factors was reflected by changes in the xanthine oxidase activity of the liver and intestine (1). Extending such observations to an entirely different species ...

Microvessel segments were isolated from rat brain and used for studies of hypoxanthine transport and metabolism. Compared to an homogenate of cerebral cortex, the isolated microvessels were 3.7-fold enriched in xanthine oxidase. Incubation of the isolated microvessels with labeled hypoxanthine resulted in its rapid uptake followed by the slower accumulation of hypoxanthine metabolites including...

We have studied the effect of oxidant stress on human lymphocyte cytotoxicity. Lymphocyte cultures maintained good viability after incubation with xanthine and xanthine oxidase. an enzyme system known to generate several highly reactive oxygen compounds. We demonstrated that these lymphocytes were viable after exposure to an in vitro oxidant stress but had a significant impairment in both antib...

A comparative study of lipid peroxidation and antioxidant potential has been made in human uterus and uterine tumor. Two types of uterine tumor used are: tumor (I), a fibroid which is the commonest benign solid tumor in uterus and tumor (II), an adenomyoma. Tumor microsomes are less susceptible to lipid peroxidation induced by both enzymic (NADPH-ADP-Fe3+ and xanthine-xanthine-oxidase) and non-...

The formation of poly(ADP-ribose) in primary cultures of rabbit synovial fibroblasts after treatment with active oxygen released by xanthine/xanthine oxidase is inhibited by addition of 1 and 10 microM 4-hydroxy-2,3-trans-nonenal (HNE). The endogenous formation of HNE by the xanthine/xanthine oxidase system is not responsible for the inhibitory effect of the aldehyde, owing to the low accumulat...

OF SPECIAL INTEREST XANTHINURIA AND HEMOCHROMATOSIS. J. H. Ayvazian. From Veterans Administration Hospital, N. Y. New England J. Med. 270: 18-22, 1964. A 47-year-old white male with hemochromatosis manifested by hepatomegaly, diabetes, greatly elevated serum iron, completely saturated iron binding capacity and hemosiderinuria, but only a trace of marrow hemosiderin, had a serum uric acid of les...