title: Dissolved urate salts out calcium oxalate in undiluted human urine in vitro: implications for calcium oxalate stone genesis.
abstract: Hyperuricosuria has long been documented as a predisposing factor to calcium oxalate (CaOx) stone pathogenesis. However, its mechanism is still without sound scientific foundation. Previously, we showed that hyperuricosuria, simulated by the addition of dissolved sodium urate, promotes the crystallization of CaOx. In the present study, we demonstrate that the urate's effect on the crystallization is attributable to its salting out CaOx from solution. Furthermore, analysis of urines revealed that their metastable limit decreased with increases in the product of the prevailing concentrations of calcium and urate: this has implications for CaOx stone genesis. We also outline anti-salting out strategies for future research for the prevention and/or treatment of CaOx calculi.
authors.affiliation: Division of Urology, Department of Surgery, Flinders University School of Medicine, Flinders Medical Centre, Bedford Park, South Australia 5042, Australia. pk.Grover@flinders.edu.au
authors.forename: Phulwinder K
authors.initials: PK
authors.lastname: Grover
authors.forename: Villis R
authors.initials: VR
authors.lastname: Marshall
authors.forename: Rosemary L
authors.initials: RL
authors.lastname: Ryall
mesh_terms: D002129:Calcium Oxalate / Q000737:chemistry* / Q000652:urine*; D011232:Chemical Precipitation; D003460:Crystallization; D006801:Humans; D006863:Hydrogen-Ion Concentration; D066298:In Vitro Techniques; D008855:Microscopy, Electron, Scanning; D014527:Uric Acid / Q000737:chemistry* / Q000652:urine*
chemical_list: D002129:Calcium Oxalate; D014527:Uric Acid