The post-mortem distributions and concentrations of calcium, silicon, and aluminum in plaque cores from brains of patients with Alzheimer's disease are being determined from elemental images and spectra acquired by wavelength-dispersive x-ray spectroscopy on a computer-controlled Cameca MBX electron beam x-ray microanalyzer. Both airdried and freeze-dried cryo- sections 8-10 micrometers thick from fresh frozen specimens with no chemical preparation are being analyzed. The drying methods will be compared for effect on elemental preservation and morphology, and quantitative results compared to those obtained by other workers using fixed material or purified cores.
