Charged particle mutagenesis at low dose and fluence in mouse splenic T cells
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Semipurified diet effect on adult pocket mice
Development of semipurifield diet for pocketmice of genus perognathus with minimal food supplementation
Altitude changes effect on brown fat content and metabolism in deer mice, noting oxygen consumption and heat production limitation by hypoxia
Activity meter has been developed using Hall effect devices that record passage of selected groups of magnetically tagged mice. Two small permanent magnets are implanted in belly and back of selected mice and electronic circuits are activated as mice move between cages. System has advantage over tagging, detecting, and identification methods currently used.
Observed changes consist mainly of blebbing of capillary endothelium and alveolar epithelium, which is quite possibly indicative of cellular edema; also, there can be observed highly-convoluted basement membrane, alveolar debris, and increased numbers of platelets.
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Results are presented of the Biocore experiment which attempted to assess the degree to which exposure to cosmic ray particle radiation might present a risk to astronauts. Pocket mice, with plastic dosimeters implanted beneath the scalp were flown in a sealed canister. The objective was to determine whether microscopically visible lesions attributable to particle radiation, could be found in brain, eye, and other tissues in these animals. The need for further study is demonstrated.
The effect of hyperthermia and/or gamma-radiation on the survival of intestinal crypt cells was studied in BDF sub 1 mice using a microcolony assay. Hyperthermia treatments, which in themselves caused no detectable cell lethality, inhibited the capacity of crypt cells to repair sublethal radiation damage. In addition, heat applied either before or after single radiation exposures potentiated lethal damage to crypt cells; the degree of enhancement was dependent on the time interval between treatments. At the levels of heating employed, DNA synthesis in the intestinal epithelium was significantly reduced immediately following exposure, but returned rapidly to normal levels. No further disturbances in cellular kinetics were observed for up to 10 days after heating.
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Male white mice were subjected to two and three week hypodynamia and then decapitated. Cytoplasmic RNA content per cell was measured by means of ultraviolet cytospectrometry. Changes in RNA content are shown, and the dynamics of the reparative processes of cells are discussed.
The differences in the dynamics of reparative processes in RNA metabolism within the neuron-neuroglia unit after the cessation of hyper- and hypodynamia is dicussed. The role of neuroglia is stressed in compensatory, reparative and trophic processes in the nervous system as well as the possibility in an adaptation at the cellular level.
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The effects on reaction time and behavior were studied for exposure to reduced oxygen concentrations in the presence and absence of carbon monoxide. Tests were run with Swiss Webster mice in a pole-jump apparatus. The results show that reaction times increase gradually with a decrease in oxygen (O2) to 10 percent O2. Below 10 percent O2 reaction times increase dramatically and performance is degraded almost immediately. At carbon monoxide (CO) concentrations of 500 ppm and reduced O2 levels, reaction times are increased even more. At CO concentrations of 1000 ppm, performance is nearly completely degraded even without reduced oxygen levels.