xanthine


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Related to xanthine: Xanthine oxidase, Xanthine DeHydrogenase, xanthine oxidase deficiency

xanthine

 [zan´thēn]
a purine compound found in most bodily tissues and fluids; it is a precursor of uric acid. Methylated xanthine compounds such as caffeine, theobromine, and theophylline are used for their bronchodilator effects.

xan·thine (Xan),

(zan'thēn),
Oxidation product of guanine and hypoxanthine, precursor of uric acid; occurs in many organs and in the urine, occasionally forming urinary calculi; elevated in molybdenum cofactor deficiency and in xanthinuria.

xanthine

/xan·thine/ (-thēn) a purine base found in most body tissues and fluids, certain plants, and some urinary calculi; it is an intermediate in the degradation of AMP to uric acid. Methylated xanthine compounds (e.g., caffeine, theobromine, theophylline) are used for their bronchodilator effect. Abbreviated X.

xanthine

(zăn′thēn′, -thĭn)
n.
1. A yellowish-white, crystalline purine base, C5H4N4O2, that is a precursor of uric acid and is found in blood, urine, muscle tissue, and certain plants.
2. Any of several derivatives of this compound.

xanthine

[zan′thīn]
Etymology: Gk, xanthos, yellow
a nitrogenous by-product of the metabolism of nucleoproteins. It is normally found in the muscles, liver, spleen, pancreas, and urine. xanthic, adj.

xan·thine

(zan'thēn)
Oxidation product of guanine and hypoxanthine, precursor of uric acid; occurs in many organs and in the urine, occasionally forming urinary calculi.

xanthine

a purine compound found in most bodily tissues and fluids; it is a precursor of uric acid. Xanthine compounds such as theophylline have diuretic properties.

xanthine calculi
see xanthine urolith.
dimethyl xanthine
theobromine.
xanthine oxidase
key enzyme in the pathway for purine breakdown. Catalyzes the conversion of hypoxanthine to xanthine and then to uric acid. Generates hydrogen peroxide, which can be a generator of free radicals in biological systems through reactions with superoxide ions.
trimethyl xanthine
caffeine.
References in periodicals archive ?
060 XH, Xanthine and hypoxanthine; CP, crude protein; TDN, total digestible nutrients; SEM, standard error of mean.
Therapeutic effects of xanthine oxidase inhibitors: Renaissance half a century after the discovery of allopurinol.
Xanthine oxidase inhibitors should not be discontinued in the event of an acute attack in the patient who is on treatment.
64 Values are given as the median (minimum-maximum) (Mann-Whitney U test) p: Plasma, e: Erythrocyte, MDA: Malondialdehyde, XO: Xanthine oxidase, SOD: Superoxide dismutase, F/M: Female/Male
13 CAT, catalase; GSH-Px, glutathione peroxidase; MDA, malondialdehyde; NO, nitric oxide; SOD, superoxide dismutase; XO, xanthine oxidase Values are mean [+ or -] SD (n=7) * P<0.
The xanthine group has a number of general physiological effects in humans, including central nervous system stimulation, Cardiac muscle stimulation, diuresis, bronchial, uterine, and vascular smooth muscle relaxation, peripheral and coronary vasodilation, and cerebral vasoconstriction.
ROS also are produced by a variety of oxidative enzymes present in cells, such as the previously mentioned xanthine oxidase.
The key claims in the new patent cover use of the entire family of drugs known as xanthine oxidase inhibitors applied to contractile disorders of the heart, including congestive heart failure.
Persistence of bovine milk xanthine oxidase activity after gastric digestion in vivo and in vitro.
Results: Exercise-induced increases in plasma markers of purine catabolism (hypoxanthine, xanthine oxidase and serum uric acid) and circulating cytosolic proteins (myoglobin, fatty acid-binding protein, and creatine kinase) were significantly attenuated by LCLT.