Biomedical subjects

J Kähler

Publications and source records attributed to J Kähler.

22 records · Page 2Linked to original sources

PubMed1993

Synthesis of leukotrienes by freshly harvested endothelial cells.

Endothelial cells produce endothelin, a powerful vasoconstrictor. We report the release of additional vasoconstrictor material in conditional filtrate from freshly harvested cells, which we identified as leukotrienes by radioimmunoassay (RIA) and by high pressure liquid chromatography (HPLC). The material was collected in cell free filtrates by superfusion of freshly harvested bovine endothelial cells attached to cytodex-3 microcarrier beads. Cells and beads form a dense network on filter paper permitting collection of cell free filtrate. The amount of leukotrienes in conditioned filtrate was 158 +/- 21 picograms/million cells. The calcium ionophore A23187 stimulated the release of leukotrienes (392.0 +/- 47.6). The peak of leukotriene production occurred within an hour after incubation of cells slowly declining thereafter. Conditioned filtrate to which indomethacin had been added caused coronary vasoconstriction in the perfused rat heart preparation, as did synthetic leukotrienes C4, D4 and E4. It was found by RIA and HPLC that some of the constrictor effect of conditioned filtrate derived from leukotrienes.

Animals↗

PubMed1993

The production of coronary vasoconstrictor substances by freshly harvested endothelial cells.

The effects of cell free superfusates from freshly harvested bovine endothelial cells attached to microcarrier beads on the isolated rabbit and rat heart and on superfused rabbit jugular veins were observed. Cell free conditioned filtrates from freshly harvested cells caused marked diminution in coronary flow and cardiac output in the isolated rabbit heart; in the perfused rat heart an increase in coronary perfusion pressure and a decline in left ventricular systolic tension and maximal left ventricular contractility (dP/dt) were recorded. Marked differences were found between changes induced by conditioned filtrate as compared to synthetic endothelin. Endothelin as present in conditioned filtrate could not account for the pronounced effect on coronary perfusion pressure, dp/dt and cardiac output induced by conditioned filtrate; more than one hundred times that of synthetic endothelin was needed to achieve comparable cardiodynamic effects. This suggested that additional non-prostanoid vasoconstrictor substance or substances are produced by freshly harvested endothelial cells. This conclusion was supported by the observation that BQ-123, a specific inhibitor of endothelin A (ETA) receptor significantly prevented contractions by endothelin, while failing to inhibit those induced by freshly harvested endothelial cells. These constrictor substances may be leukotrienes.

Animals↗

PubMed1992

The effect of immune mediators (cytokines) on the release of endothelium-derived relaxing factor (EDRF) and of prostacyclin by freshly harvested endothelial cells.

The effect of recombinant tumor necrosis factor and other cytokines stimulated by LPS (lipopolysaccharide), on the release of endothelial-derived relaxing factor and of prostacyclin was investigated using freshly harvested endothelial cells attached to plastic microcarrier beads. The results show that the cytokines failed to interfere with the release of EDRF and prostacyclin under the conditions of these experiments.

6-Ketoprostaglandin F1 alpha↗

PubMed1992

Cytokine production from freshly harvested human mononuclear cells attached to plastic beads.

The release of tumor necrosis factor (TNF), interleukin-1 beta (IL-1) and granulocyte-macrophage colony-stimulating factor (GM-CSF) from freshly harvested monocytes and lymphocytes attached to plastic beads was investigated. Previous studies had shown that freshly harvested endothelial cells attached to microcarrier beads release an endothelium-derived relaxing factor. Attachment of freshly harvested lymphocytes and monocytes to plastic beads created a dense network, consisting of 25% monocytes and 75% lymphocytes as shown by flow cytometry. Viability of cells was 90%. Monocytes were characterized by phagocytosis and non-specific esterase stain. Freshly harvested cells stimulated with lipoprotein lipase (LPS) released TNF and IL-1. Non-stimulated cells also produced GM-CSF five hours after collection of blood.

Cell Aggregation↗