George H. Morrison

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The intestinal absorption of calcium includes at least three definable steps; transfer across the microvillar membrane, movement through the cytosolic compartment, and energy-dependent extrusion into the lamina propria, Tracing the movement of calcium through the epithelium has been hampered by lack of suitable techniques and, in this study, advantage was(More)
Boron neutron capture therapy (BNCT), a binary treatment modality that can potentially irradiate tumor tissue within cellular dimensions, is critically dependent on the preferential delivery of 10B to individual neoplastic cells. In this study, ion microscopy was used to quantitatively evaluate the selectivity of p-boronophenylalanine-fructose (BPA-F) in(More)
Co-localization of the elements calcium, potassium, sodium and magnesium with sequestering organelles has been achieved by application of two microscopy techniques on the same cell. Organelles were first localized by laser scanning confocal microscopy (LSCFM) using fluorescent organelle stains. The same cells were then analyzed for elemental distribution(More)
A method for the conversion of intensity information in ion micrographs of freeze-fractured, freeze-dried cultured cells to local dry weight elemental concentrations is presented. Homogenates generated from cultured cells are used as calibration standards. Ion microscope (IM) relative sensitivity factors for B, Ca, K, Mg, and Na with respect to the matrix(More)
The ion microscope was used to study potassium and calcium distributions in the main motor organ of Mimosa pudica L. The cortex of the motor organ has two cell types differing in location, structure, and ion distribution. Histochemical features portrayed in ion micrographs were plainly correlated with structures seen in the light and electron microscopes.
The ion microscope, based on secondary ion mass spectrometry, has been used to demonstrate the distribution of calcium in the root tip cells of two plant species, Allium cepa and Vicia faba. Interphase nuclei showed higher intensities of calcium than cytoplasm, while nucleoli exhibited higher calcium intensities than the rest of the nucleoplasm. The(More)
The growing long bones from normal embryonic chicks and young rats have been examinedin situ by imaging ion microscopy, a highly sensitive technique for elemental detection and localization. In tibial diaphyses from chick and rat, treated with anhydrous ethylene glycol, embedded in Spurr medium, and dry sectioned 1–2 μm thick, analyses revealed the presence(More)
The office practices of 918 physicians selected through stratified random sampling from the College of Physicians and Surgeons of Ontario (CPSO) registry were assessed by peers and the Peer Assessment Committee of the CPSO from 1981 to 1985. The sample comprised 662 general practitioners (GPs) and family physicians (FPs) and 256 specialists in 11 fields. Of(More)