In this study, we examined the dissolution effect of dimethadione (DMO) on pancreatic stones, when kept at 37°C in a DMO 0.05 M NaHC03 saline solution which was replaced once a week, were partially dissolved during a 12-week period. The decreasing stone weight ratios were 38% (1.0 g/1 DMO), 41% (0.5 g/1), 7% (0.1 g/1), and 2% (control). The DMO solution induced a concentration-dependent increase in the solubility of the pancreatic stones associated with a concentration-dependent fall in the solution pH. The eluted calcium concentration in the solution was measured after one week\u27s incubation, and then the decrease in stone weight in theory was calculated. The decrease in stone weight in practice, however, was more than the calculated weight in theory. To determine the reason for this discrepancy, we examined the solution microscopically for sediment and found amorphous substances indicating a concentration-dependent increase in the amount of sediment. These substances resembled artificially broken pancreatic stones and they were dissolved by bubbles following the addition of acetic acid. This phenomenon suggests that these substances and pancreatic stones consist of CaC03. Therefore, it appears DMO has the potency not only to dissolve CaCO3, but also to break pancreatic stones into small pieces
