Engineering topics
Publications and source records attributed to Leon, H. A..
Automatic pair-feeding system was developed which immediately dispenses same amount of food to control animal as has been consumed by experimental animal that has free access to food. System consists of: master feeding system; slave feeding station; and control mechanism. Technique performs real time pair-feeding without attendant time lag.
Study carried out to obtain some notion of the initial phasing and interactive effects among some hormones known to be responsive to vibration stress. Sprague-Dawley derived rats were exposed to the acute effects of confinement and confinement with lateral (plus or minus G sub y) vibration. The coincident monitoring of glucose, insulin, growth hormone, and corticosterone plasma levels, during and immediately subsequent to exposure to brief low level vibration, exhibits the effects of inhibition of insulin release by epinephrine. The ability of insulin (IRI) to return rapidly to basal levels, from appreciably depressed levels during vibration, in the face of elevated levels of glucose is also shown. Corticosterone responds with almost equal rapidity, but in opposite phase to the IRI. The immuno-assayable growth hormone (IGH) dropped from a basal level of 32 ng/ml to 7.3 ng/ml immediately subsequent to vibration and remained at essentially that level throughout the experiment (60 min). Whether these levels represent a real fall in the rat or whether they merely follow the immuno-logically deficient form is still in question.
Rats were exposed to 100% oxygen at 600 torr for up to 8 days. Highly significant increases in RBC anaerobic glycolysis occurred during the first 4 days of exposure and then subsided. Two significant peaks were found, one on days 1 and 2 and one on day 4. The first peak is attributed to reticulocytosis, which was maximal after 90 minutes and had disappeared by day 3. A second mechanism must account for the peak on day 4. An interpretation of the second peak is provided by existing evidence that selective removal of older RBCs occurs during the first few days of exposure to hypobaric oxygen, with maximum effect on day 4. Results in splenectomized, sham-operated and intact animals were indistinguishable from each other. A significant decrease in RBC specific gravity was found in exposed animals with spleens intact, but not in splenectomized animals. Theoretical aspects of age-related parameters as an aid to continuous detection and evaluation of changes in RBC populations are discussed.
Oxygen exposure effect on food consumption/ utilization efficiency, growth and biochemical parameters
Dehydrogenases activities in rabbit retina homogenates exposed to oxygen at high partial pressure for various time periods
Mathematical model for rats nonlinear time-varying glucocorticoid secretion control mechanism, obtaining time dependent characteristics of hypothalamic-hypophyseal complex
Prolonged hyperoxia effect on red blood cell survival and hemolysis in rats on normal diet
Effect of high pressure oxygen exposure on red blood cells in splenectomized rats
Glucocorticoids and growth hormone factors concerned with regulation of liver protein synthesis during acute centrifugation stress
Nutritional and hormonal factors concerned with regulation of liver protein synthesis in rats during acute centrifugation stress
Design of mechanical device for stirring several test tubes simultaneously
Oxygen toxicity relation to nutrition, hormonal secretion and age factors, discussing experiments on rats
Corticosterone effect on amino acid incorporation into protein and microsomes in male rat livers
Protein synthesis in liver of adrenalectomized and hypophysectomized rats exposed to centrifugation stress
Localization and mechanism of rat liver protein synthesis by alkali metals and ammonium ions