title: Urinary excretion of urate in patients with calcium oxalate stone disease.
abstract: The diurnal variation in excretion and concentration of urinary urate was studied in 31 patients with calcium oxalate stone disease. Urate excretion was highest during the day-time, decreased in the evening and was low during the night. Meal-related peaks were observed. The concentration of urate reached the highest levels during the morning hours and, attributable to a low pH in morning urine, most samples were at this time super-saturated with respect to uric acid. In addition, many urines appeared to be at high risk of exceeding the uric acid formation product. Concerning the ion-activity product of sodium urate, supersaturated samples were frequently found, but the risk of exceeding the formation product for sodium urate at a normal urate excretion was apparently low.
mesh_terms: D002129:Calcium Oxalate; D002940:Circadian Rhythm; D003460:Crystallization; D005260:Female; D006801:Humans; D008297:Male; D012306:Risk; D014527:Uric Acid / Q000652:urine*; D014545:Urinary Calculi / Q000652:urine*
chemical_list: D002129:Calcium Oxalate; D014527:Uric Acid