FOURIER-TRANSFORM INFRARED MICROSCOPY IDENTIFICATION OF CRYSTAL DEPOSITS IN TISSUES - CLINICAL IMPORTANCE IN VARIOUS PATHOLOGIES

The presence of crystal deposits in tissues is associated with various pathologies, Sometimes their identification is useful for understandi ng the etiology or the mechanism of the disorder. The authors applied Fourier transform infrared microscopy (FTIRM) to the molecular charact erization of crystal deposits in tissue and compared the results with those provided by histologic studies using polarized light microscope and histochemical reactions. Twenty-five biopsies were investigated. I n 10 cases, the results were in good agreement. In 15 cases only FTIRM could precisely identify the crystals. In three cases, this technique allowed to characterize dihydroxyadenine crystals revealing an adenin e phosphoribosyltransferase deficiency previously undiagnosed in patie nts presenting severe chronic renal failure. In three cases, crystal d eposition was related to drug therapy, In other cases, crystal identif ication was useful to understand the mechanism of the pathology respon sible for tissue damage and crystal deposition.