PubMed · 12000933
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Peter B Farmer. 2002-05-09. Basic or applied, it's the interaction that counts.. https://doi.org/10.1038/417117a
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BACKGROUND: There are controversial reports on the effect of sodium-potassium adenosine triphosphatase (Na+-K+ ATPase) inhibition on mast cell mediator release. Some of them have indicated that ouabain (strophanthin G), a specific Na+-K+ ATPase inhibitor, inhibited the release, whereas the others have shown that ouabain had no effect or even had a stimulatory effect on the mediator secretion. Most of these studies have utilized animal-derived mast cells. The aim of this study was to determine the effect of Na+-K+ ATPase inhibition on human skin mast cells. METHODS: Unpurified and purified mast cells were obtained from newborn foreskins and stimulated by calcium ionophore A23187 (1 microM) for 30 min following a 1 hr incubation with various concentrations (10(-4) to 10(-8) M) of ouabain. Histamine release was assayed by enzyme-linked immunosorbent assay (ELISA). RESULTS: The results indicated that ouabain had no significant effect on the non-immunologic histamine release from human skin mast cells, in vitro. CONCLUSIONS: Na+-K+ ATPase inhibition by ouabain had no significant effect on the non-immunologic histamine release from human cutaneous mast cells and suggested differences between human and animal mast cells.
The effects of embedding up to 60 mol% of alpha-tocopherol (alpha-Toc) on the morphology and structure of the egg phosphatidylcholine (PC) membrane were studied using spectroscopic techniques. The resulting vesicles were subjected to turbidometric and dynamic light scattering measurements to evaluate their size distribution. The alpha-Toc intrinsic fluorescence and its quenching was used to estimate the tocopherol position in the membrane. Optical microscopy was used to visualize morphological changes in the vesicles during the inclusion of tocopherol into the 2 mg/ml PC membrane. The incorporation of up to 15 mol% of tocopherol molecules into PC vesicles is accompanied by a linear increase in the fluorescence intensity and the simultaneous formation of larger, multilamellar vesicles. Increasing the tocopherol concentration above 20 mol% induced structural and morphological changes leading to the disappearance of micrometer-sized vesicles and the formation of small unilamellar vesicles of size ranging from 30 to 120 nm, mixed micelles and non-lamellar structures.