title: Routine analysis of urinary calculi by scanning electron microscopy.
abstract: Analysis of 529 urinary calculi by SEM(EDXA) and following x-ray diffraction in nearly all cases of oxalate-rich stones reveals a certain content of calcium phosphate, which in more than 75% can be related to the central core. This confirms the idea of a primary nidus at the beginning of stone formation. The abundant appearance of Ca-phosphate bearing microspherules both in urinary calculi and in urine of known stone formers as well as the presence of similar spherules in human kidney tissue leads to a conception of the physico-chemical nature of this nidus. A proposed model about the first steps of stone formation combines the two main theories of genesis of urinary calculi, which so far have been considered contradictory.
mesh_terms: D002129:Calcium Oxalate / Q000032:analysis* / Q000652:urine; D002130:Calcium Phosphates / Q000032:analysis* / Q000652:urine; D006801:Humans; D008855:Microscopy, Electron, Scanning / Q000379:methods; D014545:Urinary Calculi / Q000473:pathology*; D014961:X-Ray Diffraction
chemical_list: D002130:Calcium Phosphates; D002129:Calcium Oxalate