N. Lemkey-Johnston

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The response of non-neuronal cells in the brain to monosodium glutamate (MSG) was studied in the neonatal mouse brain. Neurons rapidly degenerate in this chemically-induced lesion, and the glia reflect and respond to their early pyknosis and death. Astrocytic glia exhibit the most profound responses in the form of degenerative nuclear and cytoplasmic(More)
Populations of synaptic vesicles within cerebellar terminals considered excitatory or inhibitory on the basis of physiological evidence differ with respect to size and shape. Size rather than shape appears to be the main morphological difference between these populations. Elongation of vesicles is depenident on fixation with aldehyde fixatives, and both(More)
Neonatal mice received oral doses of monosodium glutamate (MSG) at levels of 0.25, 0.5m 1.0, 2.0, and 4.0 g/kg or aspartame at levels of 0.5, 1.0, 1.5, and 2.0 g/kg. Hypothalamic lesions were encountered at dose levels equal to or exceeding 0.5 g/kg (MSG) and 1.0 g/kg (aspartame). Aspartame administration resulted in a much smaller hypothalamic lesion than(More)
After receiving monosodium glutamate by stomach tube, the brains of infant macaques were perfused for examination by light and electron microscopy. No morphological differences were observed in the hypothalamic regions of treated and control monkeys. However, inadequately fixed tissue had the same appearance as that of the previously reported brain lesion(More)
Subfractionation of a standard “synaptosome” fraction from whole brain has yielded two lighter layers rich in axonal segments devoid of synaptosomes similar to those obtained from cerebellar homogenates. The heavier layers were found to contain both synaptosomes and axonal segments plus a significant population of synaptosomes with axons attached.(More)
Previous studies have indicated that fractions of unmyelinated axons can be obtained from cerebellum, whole brain or forebrain. It seemed likely that unmyelinated axons break into segments upon homogenization and that any circumscribed region of brain containing abundant unmyelinated axons could be found to yield axonal fractions. Caudate-putamen material(More)