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Biomedical subjects

J E Allen

Publications and source records attributed to J E Allen.

At least 145 records · Page 8Linked to original sources

Human red blood cells: prostaglandin E2, epinephrine, and isoproterenol alter deformability.

The human red blood cell responds to prostaglandin E(2), epinephrine, and isoproterenol with a decrease in deformability. The maximum decrease is brought about by 10(-10)M prostaglandin E(2), 10(-9)M epinephrine, or 10(-7)M isoproterenol. The dose response curve is biphasic. The sensitivity of the red cell to prostaglandin suggests that this cell may be a primary target for prostaglandin action. These changes in response to vasoactive substances indicate that the red cell must be considered an active element in circulatory control.

Blood Viscosity↗

Contribution to the co-rotating magnetic field model of the pulsar.

A new general solution of the electromagnetic field equations convenient for rotating field problems is used to analyse the case of low plasma number density. Two localized pulse emitting regions rotating with the star at approximately twice the velocity of light radius are predicted.

Journal Article↗

Oxidation of n-tetradecane and 1-tetradecene by fungi.

Cunninghamella blakesleeana (minus strain) and a Penicillium species were grown in a mineral-salts medium containing either n-tetradecane or 1-tetradecene as substrate, and ether extracts of the mycelial mats were analyzed for oxidation products. Extracts from Cunninghamella revealed tetradecanoic acid and 13-tetradecenoic acid from the oxidation of n-tetradecane and 1-tetradecene, respectively, thereby indicating that these hydrocarbons were subject to methyl group oxidation. In contrast to Cunninghamella, the Penicillium oxidized the two substrates by subterminal attacks on methylene rather than methyl groups. This was evidenced by tentative identifications of the following alcohols and ketones from oxidation of the hydrocarbons: tetradecan-2-ol, dodecan-1-ol, tetradecan-2-one, and tetradecan-4-one from n-tetradecane, and tetradecen-4-ol, 13-tetradecen-4-ol, tetradecen-3-ol, 13-tetradecen-4-one, and tetradecen-3-one from 1-tetradecene. A pathway for hydrocarbon oxidation is proposed for subterminal oxidation at the methylene alpha to the methyl group.

Alcohols↗

On the mechanism of action of aldosterone.

Studies to elucidate the mode of action of aldosterone have been carried out in the amphibian urinary bladder. The following previously reported hypotheses were evaluated: (1) aldosterone stimulates sodium transport by increasing the amount of sodium available to the sodium pump; (2) aldosterone enhances energy production for the sodium pump; and (3) aldosterone-stimulated sodium transport is obligatorily coupled to aerobic metabolism. In the present experiments, aldosterone potentiated the effect of vasopressin on sodium transport in the absence of aerobic metabolism or oxidative phosphorylation. This effect was not due to enhanced energy supply. Thus both hypotheses 2 and 3 appear not to be valid. In addition, aldosterone-stimulated sodium transport exhibited increased sensitivity to the specific inhibitor, ouabain, and this inhibition was readily reversed by K(+). These findings, as well as previously reported work, have led us to propose that aldosterone stimulates sodium transport by inducing a change either in the sodium pump itself, i.e., synthesis or activation, or in its environment in the serosal plasma membrane of the responsive cells.

Adenosine Triphosphatases↗

Teeth protector.

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Acrylic Resins↗