The role of the matrix substance in formation of urinary stones.

This study deals with the role of the stone matrix substance in formation of urinary stones. A series of coagulation experiments were conducted by determining the sedimentation rate of calcium carbonate suspension with respect to the following substances: sodium alginate, stone matrix substance, bovine albumin and chondroitin sulfate C, these were each added to a separate fine particle suspension of calcium carbonate. Changes in zeta-potential of the suspension particles after addition of the above materials were determined microscopically using Usui's method. The results obtained in this study indicate that sodium alginate, the matrix substance, bovine albumin and chondroitin sulfate C act on the suspension particles, and as a result, coagulation is produced by a decrease of the zeta-potential of the particles. Application of kinetic energy to the coagulate caused by sodium alginate resulted in the formation of a solid. From these results it is considered that the matrix substance is not incorporated by accident in urinary stones, but it participates in the formation of them.