USE OF THE NUCLEAR MICROPROBE AT THE UNIVERSITY-OF-ARIZONA FOR THE STUDY OF HEAVY-METAL DEPOSITION IN RABBIT RENAL TISSUE

Industrial wastes consigned to disposal sites frequently contain subst antial amounts of heavy metals. We have successfully applied proton in duced X-ray emission analysis (PIXE) in the conduct of heavy metal (Hg , Cd, Cr, As) toxicity studies using precision cut rabbit renal cortic al slices. The large beam diameter (4000 mu m) of the proton macroprob e at The University of Arizona Ion Beam Analysis facility allowed an o verall concentration of the metal(s) of interest in the samples to be determined, but lacked the ability to resolve point concentrations in the tissue. The ability to locate these areas has now been made availa ble to us with the addition of a rastering microprobe (mu-PIXE) to the facility. Studies now being conducted in our laboratory using this mi cro-technique include analysis of renal tissue taken from rabbits inje cted intraperitoneally with HgCl2, K2Cr2O7, and NaAsO2. The small beam size (3 mu m) and the ability to raster this beam over areas of up to 125 mu m x 125 mu m has allowed regional mapping of endogenous and no n-endogenous metal concentrations and revealed trends in heavy metal d eposition in in vivo treated renal tissue, significantly increasing th e amount of information obtained from these animal studies using PIXE alone. The combination of small beam size, high resolution, and multi- element detection makes mu-PIXE a powerful tool for investigating the impact of non-endogenous metals on the kidney. (C) 1997 Elsevier Scien ce B.V.