Inhibitory effects of urinary macromolecules on the crystallization of calcium oxalate.

Protective (inhibitory) effects of human urinary macromolecules on the crystallization of calcium oxalate were found when these urinary macromolecules were added to water or to salt solutions, which mimic human urine with respect to the concentrations of the most abundant small molecular weight species. The aspects of calcium oxalate crystallization affected by urinary macromolecules were: (i) an inhibition of nucleation (increased metastable limit), (ii) an inhibition of the crystallization rate, (iii) a decrease in the supersaturation level, and (iv) a decrease in adhesion of crystals to container surfaces.