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Xanthine

About: Xanthine is a research topic. Over the lifetime, 4046 publications have been published within this topic receiving 129820 citations. The topic is also known as: Xanthine.


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Journal ArticleDOI
TL;DR: It is suggested that the differences in PD excretion betweenbuffaloes and cattle were probably due to the smaller proportion of plasma PD that was disposed of in the urine of buffaloes, and xanthine oxidase was practically absent from plasma and intestine of sheep.
Abstract: The urinary excretion of purine derivatives (PD) was measured in six buffaloes (Bubalis bubalis) during fasting and in fourteen buffaloes given four restricted levels of roughage (2.548 kg DM/d). Only allantoin and uric acid, not xanthine and hypoxanthine, were present in the urine, the pattern of excretion being similar to that in cattle. The fasting PD excretion amounted to 0.20 (SD 0.06) mmol/kg metabolic weight (W0”*) per d, and the rate of PD excretion as a linear function of feed intake was 5.2 mmol/kg digestible organic matter intake. Both values were considerably lower than the values for cattle reported in the literature. Creatinine excretion values were 033 (SD 0.06) and 0.44 (SD 0.09) mmol/kg W075 per d determined in fasting and feeding periods respectively. Fasting N excretion was 257 (SD 49) mg N/kg Wo7’ per d. Both creatinine and fasting N excretions were also lower than in cattle. The activities of xanthine oxidase (EC 1.2.3.2) in plasma, liver and intestinal mucosa were determined in buffaloes, cattle and sheep. Xanthine oxidase activities in buffaloes were 245 (SD 2.7) unit/l plasma and 0.44 (SD 0.02) and 0.31 (SD 0.10) unit/g fresh tissue in liver and intestinal mucosa respectively. These activities were higher than those in cattle and sheep. Xanthine oxidase was practically absent from plasma and intestine of sheep. It is suggested that the differences in PD excretion between buffaloes and cattle were probably due to the smaller proportion of plasma PD that was disposed of in the urine of buffaloes. Buffalo : Purine derivatives: Xanthine oxidase

65 citations

Journal ArticleDOI
TL;DR: The interaction of reduced glutathione (GSH) with active oxygen species generated during xanthine-oxidase-catalyzed metabolism ofxanthine was investigated and the only GSH-derived product detected was oxidized glutathiona (GSSG), indicating the generation of a different radical species consistent with DMPO-glutathionyl radical adduct generation.

65 citations

Journal Article
TL;DR: Data indicate that H2O2 plays a major role in asbestos-stimulated ODC induction and proliferation of epithelial cells of the respiratory tract by altering the regulation of a gene critical to proliferation.
Abstract: Induction of ornithine decarboxylase (ODC) enzyme activity occurs after exposure of hamster tracheal epithelial (HTE) cells to asbestos and the soluble tumor promoter 12- O -tetradecanoylphorbol-13-acetate. Since active oxygen species are implicated as mediators of asbestos-induced biological responses, studies here were designed to examine whether active oxygen species generated by asbestos or oxidants caused increased ODC activity. In confluent HTE cells, significant blockage of chrysotile or crocidolite asbestos-stimulated ODC activity occurred with simultaneous addition of catalase, but not superoxide dismutase, to medium. The addition of xanthine plus xanthine oxidase caused a dose-dependent increase in ODC activity, which was inhibited significantly after addition of catalase or mannitol, indicating that H2O2 was the principal oxidant produced in that reaction. Addition of phenazine methosulfate, a redox reagent used to generate superoxide, resulted in significant elevation of ODC, which was inhibited by addition of superoxide dismutase but not catalase. Hydrogen peroxide added to culture medium also caused a potent increase in ODC activity inhabitable by catalase. Hypochlorous acid caused increases in ODC activity, although the magnitude of this response was less than that observed with other oxidants. Therefore, although all active oxygen species examined triggered ODC, less reduced species ( \rm O^{\d{-}}_{2} and H2O2) were more proficient than OH or a halogenated oxidant. All oxidants, except HOCl, caused a significant increase in [3H] thymidine incorporation at 24 or 48 h after their addition to HTE cells. In comparative studies, exposure of HTE cells to either asbestos or xanthine plus xanthine oxide increased the level of ODC mRNAs proportionate to oxidant concentration and the extent of enzyme induction. Thus, data indicate that H2O2 plays a major role in asbestos-stimulated ODC induction and proliferation of epithelial cells of the respiratory tract by altering the regulation of a gene critical to proliferation.

65 citations

Journal ArticleDOI
TL;DR: Reduction of free radical formation decreases platelet aggregation and may eliminate cyclic flow variations, whereas promotion of freeradical generation enhances platelet aggregating and may induce cyclicflow variations.

65 citations

Journal ArticleDOI
01 Oct 2018-Heliyon
TL;DR: In this paper, a review summarizes the available knowledge of xanthine based drugs development along with exploring new Xanthine led chemical synthesis path for bringing diversification in xanthines based research.

65 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
202361
2022108
202157
202060
201961
201869