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Biomedical subjects

A Livingston

Publications and source records attributed to A Livingston.

At least 91 records · Page 5Linked to original sources
PubMed1977

Microtubules in myelinated and unmyelinated axons of rat sciatic nerve.

Tannic acid in glutaraldehyde was used to stain microtubules in myelinated and unmyelinated axons of rat sciatic nerve. In the majority of areas the tannic acid failed to penetrate the unmyelinated axons whilst penetrating neighbouring myelinated axons, suggesting a difference in the ability of the two types of nerves to exclude tannic acid. Where tannic acid had penetrated the unmyelinated axons the 13 protofilament substructure and size of the microtubules appeared identical to those seen in the myelinated axons.

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PubMed1977

Microtubules in the neurosecretory neurones of the posterior pituitary of the rat.

The microtubules in the neurosecretory neurones of the posterior pituitary were studied using different electron microscopical techniques. Tannic acid staining indicated that the microtubules had a 13 protofilament substructure similar to that described for microtubules from other tissues and organisms; the dimensions of the microtubules were also similar to that previously reported. Albumen pretreatment clearly showed the microtubules running across axonal swellings, but not continuing across the nerve endings. The only organelles showing possible association with the microtubules were small vesicles and smooth endoplasmic reticulum, no association between hormone granules and microtubules could be seen.

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PubMed1976

Perivascular regions of the rat neural lobe.

Neural lobes and portions of occipital cortex from rats were examined electron microscopically following fixation in 4% tannic acid in 2.5% glutaraldehyde. The procedure allowed a clear demonstration of the perivascular space and intercellular spaces in both tissues. The perivascular spaces in the neurosecretory tissue was far more extensive than in the neural tissue and the role of this region in relation to the process of neurosecretion is discussed.

Animals↗
PubMed1976

Pituicytes in normal and Jimpy Mice.

Neural lobes of control and "Jimpy" mice were examined electron microscopically. The ultrastructure and incidence of pituicytes was examined following reports of reductions in astrocyte and oligodendrocyte populations in areas of the CNS of Jimpy mice. The failure to demonstrate any modification of structure or numbers of the pituicytes in the affected animals suggests that the pituicytes are not as closely related to the satellite cells of the CNS as has previously been proposed.

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PubMed1976

Accumulation of chlorporomazine by subcellular fractions of rat brain.

1. The study of the in vitro accumulation of [3H] chlorpromazine that a state of rapid equilibrium was reached for subcellular particles from cortex, midbrain and hindbrain of rats. 2. This accumulation was not saturable by increasing the concentration of chlorpromazine, and the relationship between accumulation and concentration was not modified by temperature, preincubation with high concentration of unlabelled chlorpromazine or by lowering the fraction concentration. 3. The highest accumulation of radioactivity was seen in the midbrain region and the lowest in the hindbrain. 4. In the cortex and midbrain the membrane fraction showed the highest accumulation. 5. The effect of pH on the accumulation indicated that a significnat rise was seen between pH 8 and 5. 6. This factor could also be explained in terms of solubility of the drug in membranes. 7. Studies on the metabolic fate of the drug during incubation indicated that there was a fairly rapid breakdown during incubation, the highest being seen with mitochondrail fractions and the least with membrane procedures. 9. It is concluded that accumulation of chlorpromazine by subcellular fractions in vitro may be associated with solubility in membranes and that the picture may be complicated by the presence of breakdown products.

Animals↗
PubMed1975

Morphology of the perivascular regions of the rat neural lobe in relation to hormone release.

Neural lobes of rats subjected to dehydration by drinking 2% saline for four days were examined electron microscopically and compared to untreated controls. The ultrastructure of the blood vessels and the tissues surrounding them were examined and it was found that, although few exocytotic figures could be seen in either group of animals, a significantly larger (P smaller than 0.01) number os small vesicles were found in nerve endings adjacent to the perivascular space in the saline treated group when compared to nerve endings not closely associated with blood vessels. No differences were found in the control group of animals, which supports the suggestion that the vesicles could arise from a membrane recapture process.

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