title: Urinary macromolecules are promoters of calcium oxalate nucleation in human urine: turbidimetric studies.
abstract: Calcium oxalate crystallization was induced in the filtered, ultrafiltered (10 kDa) and retentate fractions of 24-h urine specimens obtained from 15 male controls and 10 male stone formers, by administration of an aqueous sodium oxalate challenge to each test solution. Crystallization rates were followed by monitoring of the increase in turbidity in these fractions as a function of time. A laboratory nephelometer, previously calibrated against a Coulter counter, was used for this purpose. In addition, to facilitate interpretation of turbidity data, a Malvern particle size analyzer was used to determine crystal sizes and numbers in control urines. Crystallization rates, crystal numbers and crystal sizes were generally lower in ultrafiltered fractions than in filtered or retentate fractions, indicating that urinary macromolecules are promoters of calcium oxalate nucleation. Data for stone formers suggest that the urinary macromolecules in this group may be more potent nucleation promoters than those in controls.
authors.affiliation: Department of Chemistry, University of Cape Town, Rondebosch, South Africa.
authors.forename: A L
authors.initials: AL
authors.lastname: Rodgers
authors.forename: D
authors.initials: D
authors.lastname: Ball
authors.forename: W
authors.initials: W
authors.lastname: Harper
mesh_terms: D000328:Adult; D002129:Calcium Oxalate / Q000652:urine*; D003460:Crystallization; D006801:Humans; D008297:Male; D008875:Middle Aged; D009391:Nephelometry and Turbidimetry; D014545:Urinary Calculi / Q000652:urine
chemical_list: D002129:Calcium Oxalate