Chemolysis of artificial cystine stones (BON(N)-STONES) in vitro using a new dissolution device: First results

Background and Purpose: The treatment of cystine stones is a clinical probl em. This in vitro study was performed to establish an experimental system t hat enables standardized and reproducible investigations on chemolysis of c ystine stones to look for an improvement of dissolution strategies. Materials and Methods: Artificial spherical stones made of cystine (BON(N)- STONES) with a diameter of 0.9 cm were used. A new dissolution device was d eveloped simulating the physiological conditions in the upper urinary tract with computer-assisted online measurement of data. For chemolysis of artif icial cystine stones, different solvents (artificial urine, physiologic sod ium chloride solution, 2% acetylcysteine, 8.4% sodium bicarbonate solution, THAM, and combinations) were used. Results: Chemolysis is an effective tool in the management of cystine stone disease. Statistical analysis showed significant differences (p less than or equal to 0.05) for all solutions compared with artificial urine alone, A combination of THAM at pH 10 with acetylcysteine (2%) showed a 48-fold str onger ability to dissolve cystine calculi than did artificial urine. Conclusion: By performing standardized in vitro investigations, new basics to improve the dissolution of cystine stones have been developed. It is rec ommended to use artificial stones made of cystine and a dissolution device simulating physiological conditions for investigations on chemolysis in the future.