Crystal-matrix relationships in experimentally induced urinary calcium oxalate monohydrate crystals, an ultrastructural study.

Calcium oxalate monohydrate crystalluria was experimentally induced in male rats by administration of ethylene glycol. The crystalluria particles were separated by filtration and studied by scanning and transmission electron microscopy. They were associated with cellular degradation products. Organic material was present both on the surfaces of crystalluria particles as well as within them and was organized in radial striations and concentric laminations. It is proposed that crystal nuclei were formed by heterogeneous nucleation. These nuclei then adsorbed organic material and aggregated. The organic material polymerized resulting in the formation of a crystal-matrix unit which then grew and incorporated more organic material during the crystal growth.