title: Chemolysis of cystine calculi.
abstract: Historically, cystine stone chemolysis has been approached with 2 different categories of compounds--alkalizing agents (sodium bicarbonate and tromethamine) and, more recently, protonated thiols and disulfide compounds (alpha-mercaptopropionylglycine, N-acetylcysteine and penicillamine). To establish the relative efficacy of these agents an in vitro model was devised that simulates the clinical setting. The optimal molar concentrations for sodium bicarbonate, N-acetylcysteine and tromethamine were determined initially and then compared at these strengths. Lastly, a variety of solution combinations were made to determine if a synergistic effect could be demonstrated. Results of this study demonstrate that the combination of acetylcysteine, a protonated thiol, with the strong alkalizing agent sodium hydroxide yields the most effective solution for chemolysis of cystine stones. The mechanism of action is believed to occur by a synergistic combination of the pH dependent increase in cystine solubility, with a simultaneously occurring thiol disulfide interchange.
mesh_terms: D000111:Acetylcysteine / Q000494:pharmacology*; D001639:Bicarbonates / Q000494:pharmacology*; D003553:Cystine / Q000032:analysis*; D004357:Drug Synergism; D006801:Humans; D012964:Sodium / Q000494:pharmacology*; D017693:Sodium Bicarbonate; D012972:Sodium Hydroxide / Q000494:pharmacology*; D014325:Tromethamine / Q000494:pharmacology*; D014545:Urinary Calculi / Q000032:analysis / Q000628:therapy*
chemical_list: D001639:Bicarbonates; D014325:Tromethamine; D003553:Cystine; D012972:Sodium Hydroxide; D017693:Sodium Bicarbonate; D012964:Sodium; D000111:Acetylcysteine