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Biomedical subjects

H Breuer

Publications and source records attributed to H Breuer.

At least 55 records · Page 3Linked to original sources
PubMed1989

Coronary artery plaque rapidly induced by local electromagnetic stimulation in the baboon.

A reliable method has been developed to produce stenosis of the right coronary artery of baboons as a consequence of electrostimulation of the vessel at a chosen position. At that site a pair of electrodes were implanted and activated with a train of 9-volt pulses (length: 10 ms, separation: 100 ms) for 30 min, 5 days/week, up to 6 weeks. 13 animals were included in the experiment, 2 of those served as controls. Pathohistologically the structure of the artificially produced constrictions is similar to atherosclerotic lesions. On average the stenoses occupied 55% of the available lumen; total occlusion and no stenosis were observed in 1 case each.

Animals↗
PubMed1987

Occurrence of hydroxysteroid oxidoreductases in liver of turtles.

1. Hydroxysteroid oxidoreductases have been partially purified from the cytosol fraction (105,000 g supernatant) of liver from a fresh-water turtle (Podocnemis expansa) and a sea-water turtle (Chelonia mydas mydas) by precipitation with ammonium sulphate (AS, 10-80% saturation). 2. The following enzymes were detected (substrates in brackets): 3 alpha-hydroxysteroid oxidoreductase (androsterone), 3 beta-hydroxysteroid oxidoreductase (DHEA) and 17 beta-hydroxysteroid oxidoreductase (testosterone, oestradiol-17 beta). NAD as well as NADP were effective as cofactors. 3. In fresh-water turtle, highest activities of the 3 alpha-enzyme were measured in the 20% AS fraction (cofactor NAD), of the 3 beta-enzyme in the 60% AS fraction (cofactor NAD) and of the 17 beta-enzyme in the 40% AS fraction (cofactor NADP). 4. In sea-water turtle, highest activities were observed for all three enzymes in the 60% AS fraction. 5. Generally, enzyme activities were higher in sea-water turtles than in fresh-water turtles. The most active enzyme in both turtles was found to be the 3 alpha-hydroxysteroid oxidoreductase, followed by the 17 beta- and the 3 beta-hydroxysteroid oxidoreductases.

17-Hydroxysteroid Dehydrogenases↗