JESS: What Can It Teach Us?

Abstract

Knowledge of the chemical complexes (speciation) in urine can be extremely important in evaluating the risk of crystallization of stone forming salts. In order to determine the speciation, a database of thermodynamic constants for the wide variety of complexes that might form from the known components in urine, is required. JESS (Joint Expert Speciation System) is a software package that has such a database. In the present study, some of its applications in urolithiasis research were explored. To illustrate the effect of therapeutic complexing agents on the risk of calcium oxalate and calcium phosphate (brushite) stone formation, tetracycline was introduced into the urine model. Speciation calculations showed that the risk decreased with increasing tetracycline concentration and increasing pH. In a second application, the saturation index (equivalent to the relative supersaturation) of calcium oxalate and brushite were independently calculated while precipitation of these salts was modeled. This revealed that in mixed calcium oxalate‐brushite stones, the former salt is more likely to be the nucleus than the latter. It is suggested that JESS is a powerful tool for obtaining deep insights into the sophisticated crystallization processes which govern stone pathogenesis.