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Biomedical subjects

M H Lewis

Publications and source records attributed to M H Lewis.

186 records · Page 11Linked to original sources
PubMed1975

The venous drainage of the accessory reproductive organs of the rat with special reference to prostatic metabolism.

The venous drainage of the testis, epididymis, prostate and bladder was studied in live and recently dead rats. New evidence for a previously suggested direct venous connection between the epididymis and the prostate is presented, and a mechanism for blood flow from the deferential vein into the prostatic venous plexus under conditions of raised central venous pressure is described. The studies have also revealed discrepancies among previous reports which might be resolved by a simplified nomenclature.

Animals↗
PubMed1973

Lysine metabolism in mammals.

The enzymes involved in the initial degradative steps of lysine metabolism, lysine-2-oxoglutarate reductase and saccharopine dehydrogenase, were studied and their activities in different mammals compared. Values obtained in human, rat, pig, dog, cat, ox and sheep liver indicated that in vitro, appreciable degradation of lysine to saccharopine (4-6nmol/min per mg of protein) occurred. The specific activity of saccharopine dehydrogenase in most species studied was higher than that of lysine-oxoglutarate reductase. The rate of production of glutamate from saccharopine in each animal species was investigated and related to the rate of production of alpha-aminoadipate. The rate of formation of lysine from saccharopine, catalysed by saccharopine oxidoreductase, was examined and correlated with the dietary intake of lysine in each species studied.

Adipates↗
PubMedDate not supplied

Markers for biogenic amines in the aged rat brain: relationship to decline in spatial learning ability.

The major goal of the study was to evaluate the relationship of brain aging to individual differences in functional decline in rats. Forebrain choline-acetyltransferase (ChAT) and monoamines, including their metabolites, were examined in young and aged male Long-Evans rats in relation to their spatial learning ability. Aged rats that were unimpaired on a spatial learning task exhibited few changes in neurochemistry relative to the young group: each change in this subgroup was also evident in the remaining aged animals that were behaviorally impaired. Additional changes in neurochemical measures only found in the behaviorally impaired aged animals included decreased ChAT in the basal forebrain, striatum, and frontal cortex. A cluster analysis using the 15 neurochemical measures that were sensitive to aging yielded groupings of aged animals that differed with respect to their spatial learning ability, but not in their cue learning latencies. In this analysis the activity of ChAT in the basal forebrain and striatum appeared to be the best predictors of spatial learning impairment.

Aging↗