Electron energy-loss spectroscopical and image analysis of experimentally induced rat microliths. II.

Following a microlith-inducing diet of ethylene glycol plus ammonium chloride, intraluminal and intracellular crystals are observed in aldehyde-fixed rat proximal and distal tubule cells by light and electron microscopy. Qualitative, in-situ analysis with electron-probe X-ray microanalysis (EPMA) of these intraluminal and intracellular crystals shows the presence of calcium, a trace of magnesium, some chlorine and the virtual absence of phosphorus and sulphur. Electron energy-loss spectroscopical element (EELS) analysis and electron-spectroscopic imaging (ESI) confirm, at both sites, the presence of calcium. Selected area electron diffraction (a) confirmed the crystallinity of both the intracellular and intraluminal crystals; (b) produced identical diffractograms from intracellular crystals in proximal tubule cells and deliberately internalized exogenous COM-crystals in cultured LLC-PK1 cells and (c) produced mean dhkl-values, identical to the dhkl-values from calcium oxalate monohydrate (14-771) in the ASTM index, from 4 different intracellular crystals in proximal-tubule cells.