xanthine(redirected from xanthine calculi)
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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.
1. (Elements & Compounds) a crystalline compound related in structure to uric acid and found in urine, blood, certain plants, and certain animal tissues. Formula: C5H4N4O2
2. (Elements & Compounds) any substituted derivative of xanthine, esp one of the three pharmacologically active methylated xanthines, caffeine, theophylline, or theobromine, which act as stimulants and diuretics
xan•thine(ˈzæn θin, -θɪn)
1. a crystalline, nitrogenous compound, C5H4N4O2, related to uric acid, occurring in urine, blood, and certain animal and vegetable tissues.
2. any derivative of this compound.