The animal models of calcium oxalate stones induced by hyperoxaluria, hypercalciuria and lack of vitamin were summaried, and effects of different inhibitors and Chinese traditional medicines on the formation of calculi in animals were discussed.
The effect of supersaturation, oxalate/calcium stoichiometrical ratio (Oxa2-/Ca2+) and ionic strength on the crystallization of calcium oxalate (CaOxa) was investigated in gel systems by a double diffusion technique. The supersaturation affects the morphology, phase composition, and aggregation of CaOxa crystals. To a certain con- centration, the effect of Oxa2- ions on the aggregation of calcium oxalate monohydrate (COM) was much stronger than that of Ca2+ ions. It indicated that the increase of the concentration of Oxa2- ions can more efficiently pro- mote the formation of CaOxa stones. The increase of ionic strength and the molar ratio of Ca2+/ Oxa2- also pro- motes the aggregation of COM crystals.
The effect of phosphates structures on the morphology and phase compositions of calcium oxalate (CaC2O4) crystals was investigated in gel systems by a double diffusion technique. The phosphates studied include sodium orthophosphate (Na3PO4), sodium pyrophosphate (Na4P2O7) and sodium tripolyphosphate (Na5P3O10). The ability of phosphates to induce calcium oxalate dihydrate (COD) and to decrease the surface area of calcium oxalate monohydrate (COM) increased in the order: Na3PO4 < Na4P2O7 < Na5P3O10, and increased with their concentrations. When the concentration was 40 mmol·L-1, about 6%, 25% and 40% of COD was induced, respectively. Na4P2O7 makes the angles of COM crystals become round, and Na5P3O10 makes the angles of COM disappeared. The capacity of phosphates to induce COD and decrease the surface area of COM was benificial to the prevention and cure of urinary stones.
