EVIDENCE FOR AGGREGATION IN OXALATE STONE FORMATION - ATOMIC-FORCE AND LOW-VOLTAGE SCANNING ELECTRON-MICROSCOPY

Purpose: The aim of this investigation was to differentiate between ag gregation and crystal growth by studying the structure of oxalate ston es at high spatial resolution using recently developed microscopy tech niques. Materials and Methods: Sections from 6 complete human oxalate stones and 4 stone fragments were prepared by ultramicrotomy and exami ned by both low voltage scanning electron microscopy and atomic force microscopy. Results: The scanning electron microscopy showed lamellar structures up to 10 mu m, in size, consistent with previous results, a nd provided evidence that these structures were composed of smaller pa rticles. The atomic force microscopy clearly showed arrays of the smal l particles, whose size varied between 500 Angstrom and 2800 Angstrom. Conclusion: Our images suggest that an ordered aggregation of small c rystallites is responsible for oxalate stone formation.