title: Detection of crystallization inhibitory activity of whole urine with a gel model.
abstract: The inhibitory activity of urine on calcium oxalate crystallization was measured as an inhibitory index using a gel model modified from Schneider et al. [8]. Urine samples from 36 recurrent stone formers and 21 controls in 3 separate periods (morning, afternoon and evening) were tested. Mean inhibitory indices of greater than 0 were observed among normal controls in the 3 sampled periods and among stone formers in the morning and afternoon samples. A significantly lower (negative) value was observed in the evening samples of stone formers, indicating a higher tendency towards crystallization than normal. The gel method may be applied to identify individuals at risk of stone formation if sufficient numbers of period-defined urine samples from the individual are tested for a statistically significant mean inhibitory index but whether this is practical in a clinical laboratory will need further evaluations.
mesh_terms: D000328:Adult; D002129:Calcium Oxalate / Q000037:antagonists & inhibitors / Q000652:urine*; D002940:Circadian Rhythm; D003460:Crystallization; D005782:Gels; D006801:Humans; D008297:Male; D008954:Models, Biological; D014545:Urinary Calculi / Q000652:urine*
chemical_list: D005782:Gels; D002129:Calcium Oxalate