Heterogeneous Nucleation with Urate, Calcium Phosphate and Calcium Oxalate (39485)

Heterogeneous nucleation may constitute one of the mechanisms for the formation of renal stones of mixed composition. This process allows heterogeneous nuclei to initiate precipitation from solutions which are metastably supersaturated with respect to the precipitate. The seed of monosodium urate monohydrate, but not of uric acid, was capable of provoking nucleation of Ca phosphate and Ca oxalate. Conversely, seeds of brushite, hydroxyapatite, and Ca oxalate caused nucleation of mono-sodium urate, but not of uric acid. The seed of hydroxyapatite initiated precipitation of Ca oxalate, and vice versa. These physico-chemical experiments provide a basis for the explanation of the formation of mixed stones. The authors would like to thank Karen Holt, Oralee Waters, and Diedre Kennedy for their competent technical assistance.