An experimental study on the formation mechanism of urinary stones (author's transl)

Abstract

This study deals with the mechanism of stone formation in the urinary tract, with special reference to the measurement of ζ-potential. In this experiment, a suspension of calcium carbonate fine particles was prepared. To this suspension, 10-2-10-4% of sodium alginate, the matrix substance in the stones, bovine albumin and chondroitin sulfate C were added. The changes in ζ-potential of the suspension were determined microscopically by the method of Usui. As an coagulation experiment, the sedimentation rate of calcium carbonate particles was determined by adding the above mentioned substances. The rotatory energy of 6cpm was applied to the calcium carbonate suspension which had been added sodium alginate 10-2% and CaCl2 10-2M.Results obtained are as follows:It was demonstrated that the ζ-potential of the calcium carbonate particles decreased and became negative by addition of sodium alginate, the matrix substance, bovine albumin or chondroitin sulfate C. It was demonstrated by the sedimentation rate that marked coagulation of the suspended particles was produced by the substances mentioned above. When the rotatory energy was applied, stone like concretions were formed in the calcium carbonate suspension which sodium alginate and CaCl2 had been added to.Accordingly, it is considered that the matrix substance acts on the colloid particles in urine, and as a result, coagulation is produced by decrease of the ζ-potential and decrease of the repulsive force of the particles, and that an application of optimum kinetic energy to the coagulate results in the stone formation. It is also considered that the matrix substance is not incorporated by accident, but it does participate in the coagulation of the particles.