The mechanisms of renal stone formation and their dispersal will be studied in both whole and synthetic urines under conditions of constant super-and under-saturation. The highly reproducible constant composition kinetic method will be used over a range of ionic strength, concentration and pH typical of those in urines in order to provide information about the nature of the solid phases formed in the stone-forming process. Not only will the rate of mineralization of renal stones and synthetic calcium oxalate be determined but also the nature of the calcium oxalate and phosphate phases stabilized under different conditions of urine concentration, pH, and in the presence of ions such as magnesium, phosphate, urate, citrate, pyrophosphate, and urinary macromolecules. Mineralized surfaces will be investigated by x-ray diffraction, scanning and transmission electron microscopy, microprobe analysis, polarized light microscopy, SIMS, and infrared spectroscopy. It will be especially interesting to investigate the formation of mixed mineral phases in whole urines. The protected calcium electrode will enable reliable measurements to be made of ionized calcium in urines for the control of the de-and remineralization reactions and for estimation of complex formation. The most important mineralization inhibitors in urines from both normal and stone formering subjects will be investigated using chromatographically separated fractions. The mineralization experiments will be made with calcium oxalate, calcium phosphate, struvite, and urates salts. Studies of surface potentials of stones and synthetic stone minerals will be made in the presence of urinary macromolecules in an attempt to understand the aggregation and adhesion factors involved in stone formation. The results of this study will be helpful for the elucidation of the mechanism of renal stone formation and for the identification of new and improved chemolysis agents for dispersing stones in vivo.
| Campbell, A A; Ebrahimpour, A; Perez, L et al. (1989) The dual role of polyelectrolytes and proteins as mineralization promoters and inhibitors of calcium oxalate monohydrate. Calcif Tissue Int 45:122-8 |
| White, D J; Coyle-Rees, M; Nancollas, G H (1988) Kinetic factors influencing the dissolution behavior of calcium oxalate renal stones: a constant composition study. Calcif Tissue Int 43:319-27 |
| Lanzalaco, A C; Singh, R P; Smesko, S A et al. (1988) The influence of urinary macromolecules on calcium oxalate monohydrate crystal growth. J Urol 139:190-5 |
