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1. Bovine erythrocytes exposed to the action of an enzymic source of hyperoxide radicals (hypoxanthine + xanthine oxidase) exhibited hemolysis, which was prevented by the presence of hyperoxide dismutase. 2. Exposing bovine erythrocyte membranes to the source of hyperoxide radicals resulted in a decrease of (Mg2+ + Na+ + K+)ATPase activity which could be(More)
Erythrocyte membrane fluidity, membrane potential and acetylcholinesterase activity were estimated after in vitro combined treatment of human erythrocytes with perindoprilat and low-power red light irradiation. Membrane fluidity was determined using fluorescent labels spectroscopy; membrane potential was evaluated by means of potential-sensitive fluorescent(More)
The interaction of propranolol with model phospholipid membranes was studied using various experimental techniques. The partition coefficient of propranolol in the negatively charged membranes of vesicles prepared from phosphatidylserine and phosphatidic acid was found to be more than 20-times higher than in neutral phosphatidylcholine membranes.(More)
Superoxide dismutase, catalase and peroxidase activities were estimated in erythrocytes of the carp, the tench and the crucian carp. The enzymes showed higher activities in spring (1982) than in autumn (1981). In both seasons the highest levels of these antioxidative defense enzymes were found in erythrocytes of the crucian carp.
The hyperthermic exposure (39-49 degrees C) of human erythrocyte membranes augmented their lipid peroxidation stimulated by 0.1 mM FeCl3 + 1.5 mM ascorbate while having no significant influence on the non-stimulated lipid peroxidation. No effect of hyperthermia and lipid peroxidation on the post-exposure fluidity of the erythrocyte membrane lipids was found(More)
Results of numerous studies demonstrate that membranes are important sites of cell damage by both ionizing radiation and hyperthermia. Modification of membrane properties (mainly lipid fluidity) affects the cellular responses to radiation and hyperthermia but former concepts that membrane rigidification sensitizes cells to radiation while membrane(More)
Exposure of cells to hyperthermia induces a transient resistance to subsequent heat treatment. The specific mechanisms responsible for hyperthermic cell killing and thermotolerance development are not well understood. It seems that heat may induce at least two different states of thermotolerance, of which one is dependent on protein synthesis. The(More)
Gamma-irradiation of bovine erythrocyte membranes (0.1-4 Mrad) resulted in a decrease in the degree of order of membrane lipids, as measured by spin-labelled fatty acid esters, at the depth of C12 but not at the depth of C5. Dose dependence of this phenomenon corresponded to dose dependence of malondialdehyde formation in the membranes. On this basis a(More)
The interaction of local anaesthetics, tetracaine and procaine, with model phospholipid membranes has been examined by measurement of drug-induced quenching of the fluorescence of a membrane incorporated probe, 12-(9-anthroyl)stearic acid. The pH dependence of quenching curves obtained for neutral phosphatidylcholine and acidic phosphatidylserine bilayers(More)
Spin-label studies of the effects of hyperthermia on the erythrocyte membrane revealed a decrease in the fluidity of lipids and changes in the state of membrane proteins. The rate of haemolysis in iso-osmotic glycerol solution was increased. Changes of most of the parameters studied when plotted in Arrhenius coordinates revealed a discontinuity (critical(More)