Biological control to diminish dangers of urolithiasis.

High concentrations of phosphate, oxalate, and calcium ions in urine may cause formation of mineral deposits, i.e., urolithiasis. This is prevented in healthy individuals by substances present in trace quantities. However, there is no recognizable difference between normals and stone formers in urinary substance content. The enzymes glutamic oxaloacetic transaminase and glutamic pyruvic transaminase produce glutamic acid which retards calcium oxalate crystallization. The combined transaminase activity in 70 stone former urine samples was 12.2 +/- 4.1 IU and 31.9 +/- 10.7 IU for 47 normal controls. Incubation of stone former urine with glutamic oxaloacetic transaminase improved overall inhibitory potential, raised glutamic acid levels, and decreased aspartic acid concentrations. Correlation was established between the success of therapeutic treatment and the improvement of enzyme activity. The relative content of glutamic acid is low stone former urines and high in active inhibitory fractions of urinary materials. It is suggested that part of the mechanisms of prevention of stone formation is subjected to biological control.