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T L Kemper

Publications and source records attributed to T L Kemper.

54 records · Page 3Linked to original sources
PubMed1976

The effect of a low protein diet on the anatomical development of the rat brain.

Albino rats were conceived and suckled by mothers maintained on a 8% or an isocaloric 25% casein diet. After weaning, pups were maintained on their respective diets ad libitum. By most parameters of CNS maturation, rats on the low protein diet closely resembled their age-matched controls. only by the parameter of the ratio of brain weight to body weight did they resemble rats of a younger age. Camera lucida drawings of comparable Rapid Golgi-impregnated cortical neurons of 10-day-old control and experimental rats were nearly identical to each other. A similar finding was also noted in 30-day-old rats. However, with quantitative studies, the 30-day-old experimental animals showed a decrease in synaptic spine density and reduced dendritic length for some but not all dendritic processes. At all ages, experimental animals closely resembled age matched controls in the proportion of their brain weight that was neocortex, archicortex, and cerebellum. In these results we concur with Dobbing and Sands that developmental timetables for the brain are not affected by undernutrition, though extent of development may be.

Age Factors↗
PubMed1976

Monkey brain damage from radiation in the therapeutic range.

Twelve Macaca mulatta monkeys received 200 rads of supervoltage radiation to the whole brain per day, 5 days a week. The course in 4 monkeys was 4 weeks for a total dose of 4000 rads; in 4 monkeys, 6 weeks for 6000 rads; and in 4 monkeys, 8 weeks for 8000 rads. Four unirradiated monkeys served as controls. One from each group, sacrificed at 6 and 12 months from start of irradiation, are reported here. The results from 4000 rads were negligible; those from 8000 rads, profound, with gross brain destruction. The results from 6000 rads, within the therapeutic range, included at 6 months punctate necrotic lesions, 1 mm or less, widely scattered but with a predilection for the forebrain white matter. The reaction to these lesions ranged from an early macrophage response to calcification. Some were accompanied by focal edema. There were occasional examples of vascular endothelial proliferation. In addition, there were patches of dilated capillaries or telangiectasia. Twelve months after 6000 rads there were a few mineralized lesions and innumerable minute deposits of calcium and iron. A more active process was suggested by widely disseminated areas of telangiectasia, 6 to 12 mm in extent. The clinical course from this exposure included papilledema from the third to the sixth month and depressed visual evoked response accompanied by delta activity in the electroencephalogram from the sixth to the twelfth month.

Animals↗
PubMedDate not supplied

Dorsal raphe, substantia nigra and locus coeruleus: interconnections with each other and the neostriatum.

Using a retrograde axonal transport method, direct projections to the neostriatum were demonstrated from the dorsal raphe nucleus, a large area of the ventral midbrain tegmentum (including the ventral tegmental area of Tsai, the substantia nigra pars compacta, reticulata and suboculomotoria), and the tegmentum ventral to the caudal red nucleus. A direct projection was also found from the mediodorsal part of the substantia nigra to the rostral part of the dorsal raphe nucleus. Projections from the entopeduncular nucleus (pallidum) and the lateral hypothalamic area to the lateral habenular nucleus, and from the latter to the dorsal raphe nucleus were also found. This habenular projection arises primarily from large neurons in the medial part of the lateral habenula and also from another group of small cells immediately adjacent to the medial habenular nucleus. A non-reciprocal connection of the dorsal raphe nucleus to the locus coernuleus was also found. On the basis of these results and the data available in the literature on the possible neurotransmitters used by these various structures, it is suggested that the dorsal raphe nucleus may play an important role in brain stem modulation of neostriatal function.

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PubMedDate not supplied

Effect of a low protein diet on the anatomical development of subcortical formations.

The effects of a low protein diet during gestation, lactation, and after weaning on the anatomical development of a subcortical nucleate formation, the neostriatum, and a reticulate formation, the diagonal band of Broca, were studied. At 10, 30, and 90 days the volume of the neostriatum was decreased in the experimental rats. However, the percent of the brain volume that was neostriatum was unaffected at each of these ages. In a rapid Golgi study of individual neurons at 90 days of age there was no significant effect of the low protein diet on the dendritic length of three different types of neurons within the neostriatum. However, its heavily spined dominant neuron showed a significant decrease in synaptic spine density. In the reticular formation, there was also no significant effect on dendritic length. A minute, apparently axonless cell corresponding to the neurogliaform cell of Ramón y Cajal, showed a decrease in extent of its cell processes only in the neostriatum. When compared to cortical formations, these phylogenetically more conservative neuronal substrates appear to be more resistant to the effects of undernutrition.

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PubMedDate not supplied

The effects of cocaine exposure prior to and during pregnancy in rats fed low or adequate protein diets.

Sprague-Dawley rats were fed a diet of low protein content (6% casein), an isocaloric diet of adequate protein content (25% casein), or a laboratory chow diet for 5 weeks prior to mating and throughout pregnancy. Within each diet group, rats received either cocaine (30 mg/kg IP two times per week prior to mating and 30 mg/kg or 40 mg/kg SC daily from days 3 to 18 of pregnancy) or saline injections. Cocaine produced a greater reduction in food intake during pregnancy in the malnourished group compared with the other two diet groups. The effect of cocaine on food intake was minimal in chow-fed rats. Weight gain in pregnancy was reduced by cocaine in a dose-dependent manner, and by malnutrition. Both prenatal cocaine and malnutrition impaired skeletal maturation of the pups, but there was no additive effect of the two insults on this measure. Litter size was significantly reduced by the 40 mg/kg, but not by the 30 mg/kg dose of cocaine across all diet groups. Consequently, the 40 mg/kg dose of cocaine proved to be fetotoxic in this model. Birth weight was significantly reduced by prenatal malnutrition but not by prenatal cocaine. Gestation length was unaffected by either insult. Hence, the ability to detect a diet x drug interaction was dependent upon the variable being measured.

Analysis of Variance↗
PubMedDate not supplied

Progressive multifocal neurologic deficit with disseminated subpial demyelination.

A sixty-six year-old man developed visual and gait difficulties, a deficit in recent memory and hearing, and acute urinary retention. He subsequently became blind, deaf, and quadriparetic. Terminally, weakness deepended and he lapsed into semi-coma. The cerebrospinal fluid contained increased amounts of protein with a normal electrophoretic pattern, and a moderate mononuclear pleocytosis. Gross examination of the brain revealed normal vessels and meninges. Coronal sections showed irregular areas of subpial discoloration in forebrain and brainstem. Stains for myelin revealed scattered foci of pallor in the intracortical myelinated fibers; demyelination throughout the brainstem, most severe in subpial areas; and a focus of central pontine myelin loss. The subependymal myelin was intact throughout the neuraxis. Histological examination showed axonal preservation in areas of extreme myelin loss. Demyelination was accompanied by astrocytic gliosis showing different degrees of activity, and occasional perivascular cuffing with mononuclear cells in cerebral and meningeal vessels. Electron microscopy revealed filamentous structures in cell nuclei. These were 180-220 A in diameter, had a hollow core, and, in some tangential sections, showed cross striations. The unusual clinical picture and correspondingly striking pattern of demyelination suggest that this case might represent a distinct clinical entity.

Aged↗
PubMedDate not supplied

Effects of chronic exposure to alcohol on the developing brain.

In this investigation using Golgi techniques, the relative effects of chronic alcohol exposure and malnutrition were studied in the developing cerebral cortex of the rat. Female Sprague-Dawley albino rats were placed on one of three dietary regimens for an eight-week conditioning period: an ethanol-containing (E) liquid diet, a liquid control (LC) diet isocaloric with the E diet, and a rat chow (CH) diet. The E and LC groups were pair-fed and all diets were continued through pregnancy and lactation. In comparison to the control groups, the E group showed a significant reduction in body and brain weight with a decrease in cerebral cortical width, density of basal, oblique, and terminal spines, and extent of oblique dendrites in layer IIIb somesthetic cortical pyramidal neurons. These findings indicate that changes in the cerebral cortex in the developing rat chronically exposed to alcohol cannot be explained by malnutrition alone.

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