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Biomedical subjects

A P Slade

Publications and source records attributed to A P Slade.

7 recordsLinked to original sources
PubMed1991

The role of glutamate dehydrogenase in plant nitrogen metabolism.

In vivo nuclear magnetic resonance spectroscopy, in vitro gas chromatography-mass spectrometry, and automated (15)N/(13)C mass spectrometry have been used to demonstrate that glutamate dehydrogenase is active in the oxidation of glutamate, but not in the reductive amination of 2-oxogiutarate. In cell suspension cultures of carrot (Daucus carota L. cv Chantenay), primary assimilation of ammonium occurs via the glutamate synthase pathway. Glutamate dehydrogenase is derepressed in carbonlimited cells and in such cells the function of glutamate dehydrogenase appears to be the oxidation of glutamate, thus ensuring sufficient carbon skeletons for effective functioning of the tricarboxylic acid cycle. This catabolic role for glutamate dehydrogenase implies an important regulatory function in carbon and nitrogen metabolism.

Journal Article↗
PubMed1987

Comparison of populations of human faecal bacteria before and after in vitro incubation with plant cell wall substrates.

Human faecal slurries were incubated anaerobically with larchwood xylan, oat spelt xylan, wheat bran, apple cell walls or sugar beet pulp as sole carbon sources. The populations which developed during incubation were different from the inoculum, the most marked changes being an increase in the number of Bacteroides species and a decrease in the number of Fusobacterium species for all carbon sources tested. With a water-soluble preparation of larchwood xylan the population was dominated by species able to ferment this substrate, in contrast to the population which developed with the insoluble substrates. The ability to use one plant cell wall substrate appeared to be related to the ability to use others. Strains capable of using plant cell wall substrates included Bacteroides spp., Clostridium clostridiiforme, Bifidobacterium longum, Fusobacterium spp. and Escherichia coli. When incubation with two contrasting substrates (bran and larchwood xylan) was replicated, the populations which developed were reproducibly different from the inoculum and from each other.

Bacteroides↗
PubMed1981

Growth hormone and other responses to clonidine in patients with endogenous depression.

The growth hormone response to clonidine was significantly less in 10 drug-free patients with endogenous depression than in 10 normal subjects who were individually matched with the patients for age and sex. The hypotensive and sedative effects of clonidine in the two groups were similar. The findings may indicate a defect at central alpha adrenoceptors at least in neuro-endocrine systems.

Adult↗
PubMed1981

A pilot study of the mechanism of action of desipramine.

To test the hypothesis the desipramine alters alpha adrenoceptor function in depressed patients, the effects of clonidine upon growth hormone sedation and blood pressure have been measured in depressed patients before and after treatment with desipramine. After three weeks of treatment the hypotensive and sedative effects of clonidine were inhibited in all patients even though plasma desipramine concentrations at this time varied from 42 to 560 micrograms/l. Growth hormone responses to clonidine were enhanced in five of the six patients but this effect was not statistically significant. These findings are consistent with the hypothesis that in these patients desipramine altered alpha adrenoceptor function: other explanation are discussed.

Adult↗
PubMed1980

A neuroendocrine study of the mechanism of action of ECT.

To test the possibility that the antidepressant action of ECT is due to an enhanced responsiveness to the stimulation of monoamine receptors, we have measured pituitary hormone responses to test doses of clonidine and methylamphetamine in depressed patients before and after a course of ECT. There was no enhancement of the growth hormone response to either drug following a course of ECT. Cortisol responses to methylamphetamine were enhanced, but probably this was secondary to the partial or complete recovery of the patients. Further neuroendocrine studies of the mechanism of action of ECT in man are needed.

Adult↗