QUANTIFICATION OF CRYSTAL-GROWTH OF CALCIUM-OXALATE IN GEL AND ITS MODIFICATION BY URINARY CONSTITUENTS IN A NEW FLOW MODEL OF CRYSTALLIZATION

Purpose: To use a new flow model of crystallization to quantify the gr owth of calcium oxalate monohydrate (COM) in a gel matrix under simula ted physiological conditions. Materials and Methods: Artificial urine supersaturated in COM was conducted through channels containing a gel with COM seed crystals (flow rate: 0.5 ml. per minute; reaction time: 4 hours; 37 +/- 1C). A relative crystal growth parameter, Vcr, was qua ntified by by discontinuous measurement of scattered light intensity b y microphotometry. The effects on Vcr of varying a series of urinary p arameters were investigated within the system. Results: The following order of effectiveness in changing COM growth could be derived: diluti on > oxalate > calcium > magnesium approximate to citrate. Conclusions : Drinking therapy and lowering of urinary oxalate excretion can be co ncluded to be the most promising means of preventing CaOx urolithiasis . The new crystallization model demonstrated here should be suitable t o new applications in the investigation of urinary stone formation.