A study on the dissolution of urinary calculi with polari­zation microscope

By prepariug over 100 thin slices from 77 cases of urinary calculi mainly consisted of vesical calculi and immersing them in various solvents, the solubility of these calculi has been examined by polarization microscopy from the standpoints of the composition and structure of urinary calculi. (1) MgNH4P04·6H20 (struvite) has been found to be most soluble and it is the best example in the dissolution of urinary calculi; and as for the solvents, Versene proved to be the best solvent. (2) The alkaline pH seems to have an intimate relationship with the dissolution of uric acid calculi. (3) Calcium oxalate proved to be insoluble in any solvent. In addition, no difference in its stability against solvents could be recognized in its monohydrate or dihydrate: (4) Cystine dissolved in the 10% Versene solution. (5) Amorphous-like substance apparently was dissolved slightly in 0.5% urease solution at 37°C, however, it is not possible to dissolve this substance completely, From these results calcium oxalate and amorphous-like substance seem to be the most difficult substances to dissolve, and therefore, the bearing they have on the dissolution of urinary calculi seems to most significant. In the present stage where little is known of real etiologic factors concerning the formation of urinary calculi, in the clinical application of the dissolution of stones further studies need to be carried on, but from the very nature of construction of urinary calculi, the local dissolution methods seem to be rather difficult at present, and rather somatic dissolution in connection with prophylaxis against recurrent stones seems to be the direction in which future studies need to be carried out.