Effect of combined treatment with perindoprilat and low-power red light laser irradiation on human erythrocyte membrane fluidity, membrane potential and acetylcholinesterase activity.

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 dyes; and acetylcholinesterase activity was estimated using the Ellman method. Both perindoprilat and laser irradiation, when used separately, increase microviscosity in the polar region and hyperpolarize the membranes in comparison with control erythrocytes.

Interaction of perindoprilat with human red blood cells.

The effects of perindoprilat on the morphology and dynamic properties of human erythrocytes were studied by light microscopy, electron spin resonance spectroscopy and spectrophotometric methods. Erythrocytes were exposed to perindoprilat at 37 degrees C for 30 and 120 min. It was shown that the drug at a concentration of 0.

Effect of low-power red light laser irradiation on the viability of human skin fibroblast.

Human skin fibroblast monolayers (S-126 cell line) were exposed to laser radiation (wavelength 670 nm, power density 40 mW/cm2). The energy densities were 2 J/cm2 and 12 J/cm2, respectively, and the irradiation was carried out at a temperature of 22 degrees C. For fibroblast viability evaluation, the colorimetric assay (conversion of thiazolyl blue to formazan) was used.

Effect of perindopril therapy on fluidity and potential of erythrocyte membrane from individuals with coronary heart disease.

Erythrocyte membrane fluidity and membrane potential were measured in patients suffering from coronary heart disease (CHD) and treated with perindopril. Membrane fluidity was determined using electron paramagnetic resonance (EPR) spectroscopy, and membrane potential was evaluated using potential-sensitive fluorescent dyes. CHD does not change membrane fluidity at the depth of the 5 carbon in the fatty acid chain of membrane phospholipids.

Role of membrane components in thermal injury of cells and development of thermotolerance.

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.

Effect of hyperthermia and lipid peroxidation on the erythrocyte membrane structure.

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.

The response of pig erythrocytes to thermal stress.

The response of the pig erythrocytes exposed either to the action of a single temperature or to two different temperatures was investigated. The cells exposed to single heating indicated an increase of osmotic resistance with increasing temperature. The effect of two different temperatures depended on the time of incubation and the second temperature employed.

Purification and characterization of Cu,Zn-superoxide dismutase from common carp liver.

1. Common carp (Cyprinus carpio L.) liver Cu,Zn-superoxide dismutase (Cu,Zn-SOD) was purified and characterized.

Ligand and lipid domain stabilization of a membraneous Ca2+-ATPase during hyperthermia.

The susceptibility of the membranous Ca2+-ATPase of sarcoplasmic reticulum to enzymatic inactivation at hyperthermic temperatures was investigated. Inactivation produced a break in the Arrhenius plot at 45-46 degrees C and was accompanied by an increased mobility of spin label, covalently attached to the Ca2+-ATPase. MgADP and MgATP exerted a markedly stabilizing effect on inactivation, both at pH 7.

Membrane effects of ionizing radiation and hyperthermia.

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 fluidization potentiates hyperthermic damage have now been seriously challenged. It seems that the effects of membrane fluidity on cell responses to hyperthermia and radiation are due to an indirect influence on functional membrane proteins.

A spin label study of the effects of asbestos, quartz, and titanium dioxide dusts on the bovine erythrocyte membrane.

The effects of five UICC asbestos samples, titanium dioxide, and quartz on the bovine red cell membrane have been studied in erythrocyte ghosts by the spin labelling technique. Analysis of the electron paramagnetic resonance (EPR) spectra of two sulphydryl reactive spin labels and one fatty acid spin label in red cell ghosts showed modifications in membrane protein after asbestos treatment but no alterations in membrane lipids. In experiments with quartz no membrane changes were noted but titanium dioxide altered the proteins bound with the protein reactive spin label used in the present study.

A spin label study of the effect of chrysotile asbestos on erythrocyte membranes.

Alterations in erythrocyte membranes caused by UICC B chrysotile asbestos fibres were studied in red cell ghosts using the spin label technique. The electron paramagnetic resonance (EPR) spectra of two sulphydryl reactive spin labels and one fatty acid spin probe in erythrocyte ghosts showed membrane protein modifications but no changes in lipid fluidity caused by the haemolytic chrysotile asbestos fibres.

Hyperthermic modification of bleomycin--DNA interaction detected by electron spin resonance.

Electron spin resonance spectra of DNA labeled with each of four spin-labeling compounds have been studied to detect interaction between the antibiotic bleomycin and DNA. Only one of these labels, compound IV, resulted in a modified spectrum when bound to DNA and the latter was subjected to bleomycin. This property has been used to monitor DNA-bleomycin interactions under physiological and hyperthermic conditions.

Effect of gamma radiation on enzymatic activity and sulphydryl groups of human erythrocyte membrane.

The effect of ionizing radiation on human erythrocyte ghost membranes was studied by following changes in membrane -SH groups and activities of four membrane bound enzymes: Na+K+Mg2+ ATP-ase, Mg2+Ca2+ ATP-ase, Na+K+ATP-ase, and AChE. Irradiation up to 100 Gy gamma X-rays produced a significant decrease in the activity of ATP-ase and an increase in AChE activity. At higher radiation doses a marked decrease in the activities of all the enzymes was observed.

Effect of insulin on human erythrocyte membrane fluidity in diabetes mellitus.

The effect of insulin in vitro on the fluidity of the human erythrocyte membrane in Type I (insulin-dependent) diabetic patients and healthy control subjects was investigated using a fluorescence technique. It was found that the addition of 10(-9) mol/l porcine insulin significantly increased fluorescent probe lateral mobility in the membrane lipid layer but did not appear to produce any conformational changes of membrane proteins.

Effect of heparin on the porcine lymphocyte chromatin--II. Comparative study of sedimentation of chromatin DNA and isolated DNA.

1. Sedimentation of chromatin DNA and isolated deproteinized DNA was compared in neutral and alkaline sucrose density gradients after incubation of chromatin or DNA with various concentrations of heparin. 2.

Effect of thiol reagents and ionizing radiation on the permeability of erythrocyte membrane for spin-labeled non-electrolytes.

Four different thiol reagents: p-chloromercuribenzoic acid (pCMB), mercuric chloride (HgCl2), N-ethylmaleimide (NEM), and 5,5'-dithiobis-(2-nitrobenzoic acid) (DTNB) were employed as agents modifying the transport of a hydrophilic and hydrophobic non-electrolyte spin labels: 4-hydroxy-2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPOL) and 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO) into bovine erythrocytes. Gamma-irradiation of erythrocytes amplified the effects of pCMB, HgCl2 and NEM of inhibition of TEMPOL transport and attenuated them in the case of TEMPO transport. These results suggest that the transport of TEMPOL across the erythrocyte membrane is controlled by both superficially and more deeply located membrane -SH groups while only superficial -SH groups control the transport of TEMPO.

Seasonal variations in the activities of peroxide metabolism enzymes in erythrocytes of freshwater fish species.

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.

Effect of hyperthermia and ionizing radiation on the erythrocyte membrane.

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 hyperthermic transition in the membrane) between 46 and 50 degrees C.

Interaction of local anaesthetics with model phospholipid membranes. The effect of pH and phospholipid composition studied by quenching of an intramembrane fluorescent probe.

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 indicates that, contrary to previous suggestions, both charged and uncharged forms of amine local anaesthetics may be incorporated into lipid membranes.

Effect of .OH scavengers on radiation damage to the erythrocyte membrane.

Thiourea, and .OH scavenger, reduced the gamma-radiation-induced changes in the rigidity of erythrocyte membrane lipids, the state of membrane proteins, and lipid peroxidation. Several .

The crypto-OH radical in the damage of DNA by bleomycin-Fe2+?

1. Effects of various OH scavengers, superoxide dismutase and catalase on the formation of malondialdehyde-like products from DNA by bleomycin-Fe2+ were studied. In no case was a protective effect observed.