摘要:

Albumin carries fatty acids and has also been suggested to act as an antioxidant. In the present work, polyunsaturated fatty acids (linoleic, arachidonic, eicosapentaenoic and docosahexaenoic acids) ‐ but not palmitic and oleic acid ‐ inhibited growth of human hepatoma cells in low albumin concentration (0.5%). Growth inhibition by polyunsaturated fatty acids was prevented by albumin in a dose‐related manner in the range 0.7–5.0%. Albumin also protected against growth inhibition following catabolism (by lipoprotein lipase) of very low density lipoproteins. Vitamin E strongly counteracted the inhibitory effect of polyunsaturated fatty acids. Vitamin E and albumin appeared to have additive effects in protecting against growth inhibition by polyunsaturated fatty acids. Indomethacin did not greatly modify the polyunsaturated fatty acids effect. Growth inhibition by polyunsaturated fatty acids, as well as the level of thiobarbituric acid reacting substances (a measure of lipid peroxidation) in growth media, increased with increasing number of fatty acids double bonds. Vitamin E and albumin prevented both thiobarbituric acid reacting substances formation and growth inhibition by polyunsaturated fatty acids. The results suggest that the concentrations of albumin and vitamin E in the incubation medium are essential when studying polyunsaturated fatty acids effects on cell

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1992.tb09270.x

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY

摘要:

When Concanavalin A, 1–20 μgml‐1binds to the surface ofAmoeba proteusthe cell's response to Ca2+and to cationic inducers of pinocytosis is strikingly altered. Separately, Concanavalin A and Ca2+are weak inducers but their combined effects are intense pinocytosis and suppression of the normal inhibitory effect of Ca2+on cation‐induced pinocytosis. At high concentrations (>25 μg ml‐l) the lectin increases cellular uptake and binding of45Ca in the cell surface but the ionic permeability and the potential of the cell membrane are little changed by treatment with Concanavalin A. Subsequent addition of Ca2+starts the pinocytic cycle and causes a fivefold increase of the membrane resistance without depolarizing the cell. Neither a rise of free intracellular calcium nor an influx of45Ca preceeds formation of pinocytotic channels when Con A is applied to cells in the presence of calcium. All effects of Concanavalin A are blocked by α‐methylmannoside while succinyl‐Concanavalin A is without effects on pinocytosis. These findings suggest that crosslinking of cell surface carbohydrates reverses calcium inhibition of pinocytosis and increases the cell's pinocytotic response to cations without modifying either the bioelectrical effects or the intracellular free concentrat

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1992.tb09271.x

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY

摘要:

Sensory nerve activation will produce adherence of neutrophils to tracheobronchial microvessels. The aim of the present study was to investigate whether this adherence would lead to an influx of neutrophils into the airway lumen. To do this, we studied the effects of 20 minutes of vagal stimulation (1 Hz, 5 ms, 5 V) in anaesthetized and tracheostomized guinea‐pigs on both lung resistance, and the cell picture in bronchoalveolar lavage. Any changes were compared to those of intravenous methacholine influsion, producing similar changes in lung resistance. Since high pressure ventilation could produce lung damage, we also studied the effects of ventilation through an extracorporeal resistor, producing a similar change in transpulmonary pressure (45 ± 2 cmH2O) as vagal stimulation (42 ± 4 cmH2O). The total number of cells recovered in the lavage was not increased by vagal stimulation, methacholine influsion or the extracorporeal resistor. However, both vagal stimulation and methacholine influsion significantly increased the relative number of neutrophils in the lavage compared to sham stimulated animals (21 ± 11%, 13 ± 4% and 4±1% respectively), but the extracorporeal resistor had no effect (4 ± 2%). Our data suggests that prolonged bronchoconstrictionper semay induce an influx of neutrophils into the airway lumen of the gui

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1992.tb09272.x

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1992.tb09273.x

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1992.tb09274.x

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY