The uric acid-whewellite association in human kidney stones

A total of twelve human kidney stones, composed almost exclusively of uric acid, whewellite and organic matrix were initially studied by x-ray (powder; single crystal), scanning and transmission electron diffraction techniques prior to as well as after exposure to 0.25 M EDTA solutions (96 hours; pH 7.1). Subsequent high-resolution scanning ion probe analyses eventually detected a phosphate phase not resolved by any of those techniques. Templates of organic matter lay above and in between the radial striations of whewellite. Often juxtaposing sets of striations are not in correct register with respect to one another. A sharp transition exists in the cores of the stones and separates an area characterized by the random deposition of whewellite from one in which the latter commences to grow in the form of radial striations. This transition is expected to be mediated by a physico-chemical and/or structural control. In laminae of organic matrix sectioned from EDTA-untreated cores well developed spherules are detected. Those superimpose on a substrate characterized by a considerable degree of crosslinking. Maximum spherule width is of the order of 0.8 micron. There is evidence of deposition in between the spherules. That deposition pattern appears to be controlled by the morphology and location of the spherules, thus suggesting that it is secondary to spherule formation.