A device for extracting biliary or urinary stones, calculi or the like from the biliary or urinary tract of a patient including a catheter shaft, a first expandable apparatus for dilating the tract entrance or the sphincter thereat, and a second expandable apparatus for capturing the stone andor urging it out of the tract. The product has a registration code associated with it. Also disclosed is a method of making active site mutants of proteolytic tryptases in a eukaryotic host cell, expression constructs which drive the production of the mutants in transformed eukaryotic host cells, and genetically-engineered eukaryotic host cells containing the expression constructs and which express the active-site mutated form of proteolytic tryptases.