Membrane Alterations

Potentiometric electrodes also can be designed to respond to molecules by incorporating a reaction producing an ion whose concentration can be determined using a traditional ion-selective electrode. Gas-sensing electrodes, for example, include a gas-permeable membrane that isolates the ion-selective electrode from the solution containing the analyte. Diffusion of a dissolved gas across the membrane alters the composition of the inner solution in a manner that can be followed with an ion-selective electrode. Enzyme electrodes operate in the same way. 

Once apoptosis is triggered, a stereotyped sequence of premitochondrial events occurs that executes the cell death process. In many cases proteins and/or lipid mediators that induce changes in mitochondrial membrane permeability and calcium regulation are produced or activated. For example, the pro-apoptotic Bcl-2 family members Bax, Bad and Bid may associate with the mitochondrial membrane and modify its permeability. Membrane-derived lipid mediators such as ceramide and 4-hydroxynonenal can also induce mitochondrial membrane alterations that are critical for the execution of apoptosis. 

Although the topic of anaesthesia is hugely complicated, it is clear that the physiological effect of the compounds depends on their entrapment in the blood. Once dissolved, the compounds pass to the brain where they promote their narcotic effects. It is now clear that the best anaesthetics dissolve in the lipids from which cell membranes are generally made. The anaesthetic probably alters the properties of the cell membranes, altering the rates at which neurotransmitters enter and leave the cell. 

After this, the obtained suspension was processed in a homoge-nizer (Emulsiflex-C5, Avestin Inc., Ottawa) operated at a pressure at the homogenization valve of 300 kPa. The particle size was 230 nm after a homogenization period of 30 minutes. The final process step was extrusion using polycarbonate membrane Alters with a pore size of 100 nm installed in the... 

Vincristine resistance has been studied in Chinese hamster ovary cell lines cells resistant to vincristine also are resistant to vinblastine and vindesine. Suggestions were made that, in cells with relatively low levels of drug resistance, at least two prominent mechanisms of resistance can occur (22). In the first instance, cellular resistance may be attributable to membrane alterations that are reversible, functionally, by treatment with verapamil. In the second, resistance has been postulated to be due to an altered sensitivity of tubulin to the effects of the drugs the primary basis for postulating an altered interaction with tubulin was that a subgroup of cells resistant to vincristine showed enhanced sensitivity to taxol, a drug that can stabilize microtubules. It should be emphasized that differential sensitivities of tubulins from different tumor cells to the effects of vincristine or vinblastine has been proposed as a basis for the susceptibilities of cells to the cytotoxic effects of such drugs (23). Differences have been described in the electrophoretic patterns for tubulins obtained from vin-... 

Han, Y., Randell, E., Vasdev, S., Gill, A., Gadag, V., Newhook, L. A., Grant, M., and Hagerty, D. (2007). Plasma methylglyoxal and glyoxal are elevated and related to early membrane alteration in young, complication-free patients with Type 1 diabetes. Mol. Cell. Biochem. 305,123-131. 

Muriel P, Mourelle M. 1990. Prevention by Silymarin of membrane alterations in acute CCH liver damage. J AppI Toxicol 10 275-279. 

Changes occur at the cell surface and plasma membrane in the early stages of apoptosis. One of the major plasma membrane alterations is the translocation of phosphatidylserine (PS) from the inner side of the plasma membrane to the outer layer for external exposure (FI). This change of exposure requires the activation of caspase-3, a Ca flux over the plasma membrane, and a change in Bcl-2 family (B8,B13, M6). 

Peridex Disrupts cell membranes Altered taste sensation O O... 

Mechanism of Action A fungistatic antifungal that interferes with cytochrome P-450, an enzyme necessary for ergosterol formation. Therapeutic Effect Directly damages fungal membrane, altering its function. 

Chemicals produce adverse effects in the developing embryo and fetus by a variety of mechanisms (Bishop Kimmel, 1997). These may involve interactions of the exogenous agent with endogenous receptors, adduction of reactive intermediates to DNA or proteins, lipid peroxidation, enzyme inhibition, cell membrane alterations and others (US NRC, 2000). 

Peptide, amine, and eicosanoid hormones act outside the target cell on specific receptors in the plasma membrane, altering the level of an intracellular second messenger. 

Elias, P.M., N.S. McNutt, and D.S. Friend. 1977. Membrane alterations during cornification of mammalian squamous epithelia A freeze-fracture, tracer and thin-section study. Anal Rec 189 577. 

Inada, H., W.I. Higuchi, and A. Ghanem. 1994. Studies on the effects of applied voltage and duration on human epidermal membrane alteration/recovery and the resultant effects upon iontophoresis. Pharm Res 11 687. 

All these data provide evidence that, whenever an organism has to enhance its functional activity by compensatory means, the membranes alter their fatty acid composition. This points to the multifunctional role played by docosohexaenoic acid in a wide variety of adaptation processes it is an adaptogen , assisting the complicated processes which occur in cell membranes. 

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