Calcium oxalate crystal growth. A new constant composition method for modelling urinary stone formation.

A new highly reproducible method is described for the study of calcium oxalate crystal growth. After well-characterized seed material is added to stable supersaturated solutions of calcium oxalate, calcium and oxalate ion concentrations are maintained constant by the simultaneous automatic addition of reagent solutions containing these ions, controlled by a specific ion calcium electrode probe. This method simulates in vivo conditions and the influence of potential inhibitors, including urines, can be conveniently studied in terms of a simple Langmuir adsorption isotherm. For comparison of different urine samples, only a single mineralization experiment is required.