Elevation of the metastable limits and absence of container surface nucleation for calcium oxalate crystallization in a urothelial-lined system as compared to glass containers.

We studied the metastable limits of calcium oxalate supersaturation in glass tubes and in urothelial-lined rat bladders from a solvent system consisting of 0.9 per cent saline. The metastable limit was significantly elevated at 30 min in the urothelial-lined system as compared to the glass-surfaced containers. Heterogeneous nucleation on the container surfaces consistently occurred with the saline solvent in glass tubes as the metastable limit was exceeded. Intraluminal or free-floating crystals (? homogenous nucleation) without container-adherent crystals occurred with the saline solvent in urothelial-lined containers. This study reveals important properties of crystallization in urothelium and emphasizes the potential errors in extrapolating from crystallization studies in vitro in glass containers to crystallization phenomena in biological systems.