Figure 2.

Electron micrographs of selected precipitates as developed in postprandial urine (A-1 - C-1), the pertinent energy peaks of elements, and the calcium/phosphorus peak ratio (inserted as Ca/P; A-2 and B-2). Note that in A-1 - C-1 the scale is different, and that in B2 (coexistence of mature CaOx crystals and poorly crystallized CaPi) the peaks of potassium (K_Kα) and chloride (Cl_Kα) are impressive (for further information see text). A-1: Massive accumulation of mostly spheroidal CaPi crystals and interspersed rhomboidal CaOx dihydrate crystals (arrowheads). Note that Ca/P is approx. 1.6, indicative of hydroxyapatite; the situation is typical for Ca excess at urine pH 6.0 of patients in whom the first appearing crystal was CaPi. B-1 and B-2: Co-precipitation of CaOx (left arrowhead) and poorly crystallized CaPi (right arrowheads); note that Ca/P is approx. 1.0; the situation is typical for Ca excess at urine pH 6.0 of patients in whom the first appearing crystal was CaOx. C-1 and C-2: Rhomboidal CaOx dihydrate (weddellite), typically formed upon induction of Ox excess at original urine pH (for more information see text and Table 3). Note the absence of a P peak. Reproduced from [18] with kind permission of Walter De Gruyter, Berlin, Germany.