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Biomedical subjects

J Höper

Publications and source records attributed to J Höper.

13 recordsLinked to original sources
PubMed1978

Action of norepinephrine on microcirculation and PO2 distribution in the isolated perfused rat liver.

The addition of a potent vasoconstrictor, such as norepinephrine, induces an influx of sodium and an efflux of calcium and potassium in the parenchymal cells of the perfused liver. This reaction can be reversed by the addition of dihydroergotoxine mesylate (active substance of Hydergine). The example shows clearly that very distinct biological signals are generated under such conditions at the membrane level of the hepatocytes and presumably of other cells of liver tissue. At present, our investigations cannot clearly answer the question of whether or not swelling the shrinkage of parenchymal cells and of endothelial cells can serve as an additional mechanism for regulating microcirculation.

Animals↗
PubMedDate not supplied

Disturbances of extracellular pK, pNa and pH during no-flow anoxia.

The initial period of no-flow anoxia can be divided in at least two parts. During the first period lasting approximately 1 min., the O2 available in tissue gives rise to CO2 which increases hydrogen ion activity and may lead to Na+ influx2 (presumably due to increased membrane permeability to Na+). In the second period, starting after the first minute, the increase in lactate content leads to further decrease in pH and is accompanied by extensive sodium influx and a distinct potassium efflux. However, it is striking that the isolated perfused rat liver is able to tolerate 1 hour of norm-flow anoxia without severe cellular damage, whereas two minutes of no-flow anoxia lead to a decrease in cellular ATP content by 28%.

Adenosine Triphosphate↗
PubMedDate not supplied

Oxygen supply to the cirrhotic liver following various portacaval shunt procedures.

Direct measurements of local oxygen pressure by means of a platinum multiwire electrode were performed to investigate the effect of five different portacaval shunt procedures on hepatic oxygen content in the cirrhotic rat liver. End-to-side shunt, side-to-side shunt, mesenterico caval shunt, splenocaval shunt, and portacaval transposition were performed and surface PO2 was determined immediately after operation, 24 hours following operation and after one week. Portacaval transposition and end-to-side shunt led to a striking oxygen deficit of the liver tissue with no incidence of compensation by the hepatic artery; Oxygen supply was improved considerably by a side-to-side shunt and tissue hypoxia could be prevented by a mesenterico-caval shunt and splenocaval shunt. This improving effect is thought to be due to the pancreatico-duodenal venous blood supply which should be carefully preserved for the liver circulation when a shunt needs to be performed.

Animals↗