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The paper describes the use of liposomes and erythrocytes membrane as a real membrane models to evaluate the potential benefits of several plants extracts and two flavones in relation to lipid peroxidation. The antioxidant behaviour of the plant extracts from pine (Pinus silvestris L), hawthorn (Crataegus oxyacantha L, two extracts: from hawthorn’s leaves-l and bark-b), evening primrose (Oenothena paradoxa Hudziok – three extracts differ in procyanidins content P1, P2 and P3) and rosemary (Rosmarinus officinalis, as a standard for extracts) and flavones of baicalin and rutin have been studied. The results obtained showed that the studied extracts exhibited differentiated, dose-dependent antioxidant activity against phospatidylcholine liposomes (rosemary>pine≈hawthorn-l>hawthorn-b≈P1≈P2≈P3; statistically significant differences were observed between the extracts at p≤0.05) and erythrocyte membranes (rosemary≥hawthorn-b≈hawthorn-l>P1≈pine>P2≈P3) when the oxidation was induced by UV-C radiation. They also reduce the oxidation of liposomes and erythrocyte membrane when its oxidation was induced by 2,2’-azobis(2-amidinopropane) dihydrochloride (pine≥P1≈P2≈rosemary≈P3 in the case of liposomes and rosemary>> pine≥P1≈P2≥P3 in a case of erythrocyte). Moreover, the results of the study show that baicalin is characterised by high inhibition ability towards liposome PC peroxidation, as well as towards erythrocyte ghosts, when oxidation was initiated by UV radiation. However, at the same experimental conditions, the inhibitory capacity of rutin was about 7-8 times weaker. The presence of cholesterol in liposome membrane decreased the level of membrane peroxidation but do not influenced on the antioxidant activity of hawthorn extract.
The organophosphorus insecticide bromfenvinfos (2-bromo-l-(2,4-dichlorophenyl)vinyl diethyl phosphate) and its methylated homologue methylbromfenvinfos inhibited noncompetitively the activity of (Ca2+ + Mg2+)-ATPase bound to and solubilized from pig erythrocyte membrane. Both enzyme preparations exhibited biphasic substrate curves displaying the existence of two functional active sites with low and high affinity to ATP. Inhibition of activity was more pronounced for bromfenvinfos than for methylbromfenvinfos and the solubilized enzyme preparation was more affected than the bound one. The results of the experiment suggest that the insecticides inhibited the ATPase by binding to a site on the enzyme rather than by interaction with associated lipids, although their presence could weaken the action of the compounds due to the stronger affinity of organophosphorus insecticides for lipids rather than for proteins.
Preliminary experiments revealed that ferrylmyoglobin decayed more slowly in the absence than in the presence of intact erythrocytes and erythrocyte membranes. This suggested the existence of interactions between FerrylMb and the erythrocyte membrane. Subsequent studies examined the influence of FerrylMb on the membrane of intact erythrocytes and on isolated erythrocyte membranes. The incubation of intact erythrocytes with FerrylMb did not influence their osmotic fragility or the fluidity of their membranes; the level of peroxidation of the membrane lipids increased only slightly (there was only a slight increase in the level of membrane lipid peroxidation). The activity of acetylcholinesterase significantly increased after 15 minutes of incubation, whereas longer incubation did not lead to any changes in the activity of this enzyme. The incubation of isolated erythrocyte membranes with FerrylMb resulted in an increase in their fluidity and a significant rise in the level of lipid peroxidation.
The effect of N,N-dimethylaminoethyl esters of fatty acids (DM n) on pig red blood cell hemolysis and erythrocyte membrane fluidity has been investigated. In the hemolytic experiments the hemolytic activity of the compounds studied was determined, and was found to increase with alkyl chain length and followed the sequence: DM-15 > DM-13 > DM-11 > DMDA > DM-9. The fluorimetric studies were done using the fluorescent probe TMA-DPH, which allowed us to calculate polarization coefficient P and hence determine relative changes in membrane fluidity induced by the lysosomotropic substances. The compounds of highest hemolytic activity, which have fifteen- and thirteen-carbon-atom alkyl chain (DM-15 and DM-13), significantly affect the erythrocyte membrane fluidity.
Cationic gemini surfactants are an important class of surface-active compounds that exhibit much higher surface activity than their monomeric counterparts. This type of compound architecture lends itself to the compound being easily adsorbed at interfaces and interacting with the cellular membranes of microorganisms. Conventional cationic surfactants have high chemical stability but poor chemical and biological degradability. One of the main approaches to the design of readily biodegradable and environmentally friendly surfactants involves inserting a bond with limited stability into the surfactant molecule to give a cleavable surfactant. The best-known example of such a compound is the family of ester quats, which are cationic surfactants with a labile ester bond inserted into the molecule. As part of this study, a series of gemini ester quat surfactants were synthesized and assayed for their biological activity. Their hemolytic activity and changes in the fluidity and packing order of the lipid polar heads were used as the measures of their biological activity. A clear correlation between the hemolytic activity of the tested compounds and their alkyl chain length was established. It was found that the compounds with a long hydrocarbon chain showed higher activity. Moreover, the compounds with greater spacing between their alkyl chains were more active. This proves that they incorporate more easily into the lipid bilayer of the erythrocyte membrane and affect its properties to a greater extent. A better understanding of the process of cell lysis by surfactants and of their biological activity may assist in developing surfactants with enhanced selectivity and in widening their range of application.
Our study concerns the effects of exposure to lead chloride on the morphology, K+ efflux, SO4 − influx and GSH levels of the human erythrocyte. Blood was collected in heparinized tubes and washed three times. The cells were suspended at 3% hematocrit and incubated for 1 h at 25°C in a medium containing increasing concentrations of lead chloride (0, 0.3, 0.5 and 1 μM). After incubation, the suspensions were centrifuged and the erythrocyte pellets were divided into three aliquots for testing. The results show: an increase in the permeability of erythrocytes treated with lead chloride with consequent damage and cellular death, especially in the presence of high concentrations; an increase in potassium ion efflux; alterations in the morphology and membrane structure of the red blood cells; and a decrease in sulphate uptake, due either to the oxidative effect of this compound on the band 3 protein, which loses its biological valence as a carrier of sulphate ions, or to a decrease in the ATP erythrocyte concentration. In conclusion, the exposure of erythrocytes to Pb2+ ions leads to a reduction in the average lifetime of the erythrocytes and the subsequent development of anemia. These data are discussed in terms of the possible effect of lead on the reduction-oxidation systems of the cell. Oxidant agents, such as lead, are known to cross-link integral membrane proteins, leading to K/Cl-cotransport. The increased K+ efflux affects the altered redox state.
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