[The effect of local anesthetics on the electric properties of black flat bilayers]. / Vliianie mestnykh anestetikov na élektricheskie svoistva ploskikh chernykh bisloev.

The effect of some local anesthetics on conductance of bilayer lipid membranes made of egg yolk lecithin has been studied. Low concentrations of anesthetics were shown to gradually increase the integral conductance of bilayers. This effect is connected with the protonophore activity of the tested anesthetics and it caused the stabilization of the bilayers. High concentrations of anesthetics caused destabilization of membranes and formed zones of nonselective increased conductance.

[Effect of beta-lactam antibiotics on lipid bilayer membranes. I. Penicillin antibiotics]. / Vliianie betalaktamnykh antibiotikov na bisloinye lipidnye membrany. I. Penitsillinovye antibiotiki.

Interaction between penicillins and model membrane systems, flat black bilayer lipid membranes (BLM) composed of vegetable or bacterial phospholipids was studied with an account of the complicated structure of bacterial cell membranes and possible presence in them of "pure" bilayer lipid areas. By their effect on electroconductivity of the BLM the antibiotics could be divided into three groups: those having no effect on the BLM electroconductivity at the maximum concentrations i.e. benzylpenicillin, carbenicillin, piperacillin (at pH 6.0 and 7.0) and ampicillin (at pH 6.0), those insignificantly changing electroconductivity of the BLM i.e. carfecillin and azlocillin and those having a significant effect on the BLM electroconductivity i.e. ampicillin N-acyl derivatives and 6-APA. The effect of ampicillin on the BLM conductivity markedly depended on the electrolite pH. The penicillins bound to the bilayer and induced changes in the transmembrane potential (evident from the changes in the second harmonic of the capacitive current) and the BLM elasticity-capacitance parameters (evident from the changes in the ratio of the amplitudes of the first and third harmonics). It was shown that all the penicillins penetrated through the BLM composed of either vegetable or bacterial phospholipids. The capacity for the transmembrane transfer without changing of the bilayer conductivity must be connected with the fact that the penetrating antibiotics did not induce any changes in the BLM structure. The effect on the conductivity probably depended in its turn on the form of the molecule and the ratio of the hydrophilic and hydrophobic parts in it.

[Effect of beta-lactam antibiotics on lipid bilayer membranes. II. Cephalosporin antibiotics]. / Vliianie betalaktamnykh antibiotikov na bisloinye lipidnye membrany. II. Tsefalosporinovye antibiotiki.

Interaction of cephalosporin antibiotics with flat bilayer lipid membranes (BLM) composed of vegetative or bacterial phospholipids was studied with respect to their effect on electroconductivity, capacity for binding to the bilayers and capacity for transmembrane transfer through the bilayers. By their effect on conductivity, the investigated cephalosporins could be divided into three groups: those having no effect on conductivity at the maximum concentrations (up to 1 mg/ml) i.e. cefoperazone, cefotaxime and ceftizoxime, those having an effect on conductivity at concentrations of 0.2 to 0.5 mg/ml i.e. cephalexin and cephalothin and those having a significant effect on conductivity at concentrations of 10 to 60 micrograms/ml i.e. N-acyl derivative of 7-ACA (substance 64) and 7-ACA derivative (substance 71). The cephalosporins had a capacity for binding to the bilayers and for incorporation into the bilayers. They penetrated to some extent through the bilayers composed of either vegetable or bacterial phospholipids. The lower rate of penetration through the BLM as compared to that of penicillins must be due to lower hydrophobicity of the cephalosporin molecules as compared to that of penicillins.

[Thermotropic behavior of liposomes from egg yolk lecithin, hydrogenized egg yolk lecithin and their mixtures]. / Termotropnoe povedenie liposom iz iaichnogo letsitina i gidrogenizirovannogo iaichnogo letsitina i ikh smesei.

The thermotropic properties of multilamellar liposomes from egg yolk lecithin, hydrogenized egg yolk lecithin and several mixtures of these two lipids were studied with the application of excimer--forming optical probe pyrene and microcalorimetry. It was discovered that when the proportion of the egg yolk lecithin in the lipid mixture was raised the temperature of the main phase transition reduced. For all this, independent of the lipid mixture composition when the temperature was raised, apparently, polarity of pyrene microenvironment in the liposomes bilayers decreased. On the basis of the analysis of solidus and liquidus curves obtained from calorimetric studies of the lipid mixtures and bend points of Arrhenius anamorphose obtained during the pyrene excimer formation measurements some conclusions were made about the role of unmodified and hydrogenized egg yolk lecithin cluster formation in the determination of thermotropic properties of the liposomes from the above two lipids mixtures. High temperature phase transition discovered for the egg yolk lecithin while measuring the pyrene excimer formation is proposed to be closely connected with temperature-dependent changes in the organization of phospholipid heads on the interphase bilayer/H2O solution.

[The action of gramicidin S on the ionic permeability of bilayer lipid membranes]. / Deistvie gramitsidina S na ionnuiu pronitsaemost' bisloinykh lipidnykh membran.

The effect of cyclic decapeptide of gramicidin S on electrical conductivity of bilayer lipid membranes has been studied. The integral conductivity of bilayer has been shown to increase with the growth of antibiotic concentration. The integral conductivity increase occurs as series of conductivity discrete leaps, differing in amplitude from fluctuations of conductivity caused by linear gramicidins. In the series of selectivity of bilayer membranes for cations of alkaline metals the rubidium ion is before the cesium ion. This is the only difference between this series and the series of relative ionic mobility series of cations of alkaline metals in water solutions.

[Research on high-temperature transition in liposomes made from egg yolk lecithin]. / Issledovanie vysokotemperaturnogo perekhoda v liposomakh iz iaichnogo letsitina.

The pyrene eximerization, polarity of pyrene microenvironment and relaxation times (T1 and T2) of water protons in the systems of monolamellar egg yolk lecithin liposomes were investigated depending on temperature and bilayer modification by cholesterol and alpha-tocopherol. The thermotropic transition of pyrene eximerization degree at 38 degrees C, abrupt polarity change of pyrene microenvironment at 22-25 degrees C in modified by tocopherol liposomes and abnormal behaviour of water proton relaxation times in the temperature range of 39-40 degrees C were found. This high-temperature transition is supposed to be due to the structural alteration in the region of egg yolk lecithin heads.

[Effect of the C35 analog of dolichol on the electrical properties of planar black bilayers]. / Vliianie C35-analoga dolikhola na élektricheskie svoistva ploskikh chernykh sloev.

The effect of C35-dolichol on black planar bilayers from mixture of azolectin and cholesterol has been studied. C35-dolichol in concentration of about 10(-6) g/ml has been found to raise the bilayer conductivity, inducing current jumps with unclearly expressed conductivity level of 0.4-0.5 nSm. According to the data of the first and third harmonic during the several minutes after C35-dolichol addition along one side of the bilayer the capacity of the membranes and transversal module Young increase. It is supposed that dolichols induce the nonbilayer structure in membranes that is the basis for their transfer of oligosaccharides blocks across the membranes of Golgi apparatus.

[Current fluctuations across the bilayer membrane in the presence of prostaglandin F2 alpha]. / Tokovye fluktuatsii cherez bisloinuiu membranu v prisutstvii prostaglandina F2 alpha.

The prostaglandin F2 alpha (in concentration 1,4 or 14 microM) has been shown to induce the current fluctuations across the bilayers under the action on the planar bilayer membranes from the soya total phospholipids. The current fluctuations depend on the potential, their number expresses indistinctly and corresponds to the conductivity jumps across the bilayer about 5 pSm.

[Action of natural and synthetic antioxidants on the electrical parameters and stability of natural and artificial membranes]. / Izuchenie deistviia prirodnykh i sinteticheskikh antioksidantov na élektricheskie parametry i ustoichivost' prirodnykh i iskusstvennykh.

The effect of antioxidants alpha-tocopherol and ionol on membranes of human red cells and bilayer lipid membrane (BLM) from azolektin has been studied. Ionol at concentration 4-10 mM induces the hemolysis of erythrocytes, the cells form changes are observed at concentration 2 mM alpha-tocopherol doesn't show the hemolytic properties at concentration 23 mM. The ionol concentration 1 mM doesn't change the form of the cells, but influence the passive electric parameters: the capacity (Cs) of erythrocytic membrane increases and the intracellular conductance (chi i) decreases. Tocopherol (3 mM) induces the decrease both Cs and chi i. The fast increase of membrane conductance is almost immediately registered on one side of BLM at addition of ionol (0,2-0,4 g/ml). Phosphatidylionol synthesized from ionol and contining the acyl chains C15H31 and C17H35 doesn't influence the electrical properties of BLM.

[Thermotropic changes in the conductivity of black bilayers from egg phosphatidylethanolamine]. / Termotropnye izmeneniia provodimosti chernykh bisloev iz iaichnogo fosfatidilétanolamina.

Current fluctuations in black bilayers from phosphatidyl ethanolamine obtained from egg lecithin were registered in the temperature region of the main phase transition of this phospholipid and the bilayer--hexagonal phase transition about 35 degrees; they correspond to the conductivity changes of hundreds of pSm. This transition takes place in the same temperature region as shown by 31P-NMR and depolarization of light-scattering method in phosphatidyl ethanolamine multilamellar liposomes. The scheme of bilayer transformation into hexagonal phase in the temperature region of lipid polymorphic transition is discussed.

[Simple method of recording the kinetics of cell agglutination and aggregation]. / Prostoi metod registratsii kinetiki aggliutinatsii i agregatsii kletok.

The light scattering measure method for studying the kinetics of cell agglutination and aggregation under conditions of continuous and uniform stirring of suspension has been suggested.

[Use of bromthymol blue for studying the thermotropic properties of the liposomes from egg lecithin]. / Primenenie bromtimolovogo sinego dlia issledovaniia termotropnykh svoistv liposom iz iachnnogo letsitina.

The dependence of the turbidity changes at 615 nm monobilayers liposomes from egg yolk lecithin in the presence of bromothymol blue on temperature and storage conditions has been investigated. It is established that the thermotropic properties of liposomes change irregularly and depend on the storage conditions. Sharp release of the bound dye at temperature above 35-37 degrees C is associated with thermotropic change in liposomes and the detected effects, with the change of orientation of the phosphorylcholine group.

[Kinetic method of registering cell agglutination in suspension]. / Kineticheskii metod registratsii aggliutinatsii keltok v suspenzii.

A method based on changes in cell light scattering during agglutination is proposed for registration of cell agglutination in suspension. Unlike other methods of investigation of cell agglutination, our measurements are made under constant stirring and minimal stress tension in specially constructed cells. Possibilities of the method are shown upon registration of agglutination of trypsinized rabbit erythrocytes caused by PHA, Ca ions or by a sample containing lectin isolated from the fresh water algae Chara. The sensitivity of our method is higher, than that with the microtitration according to Tacashi, and makes it possible to investigate the agglutination process kinetics.

[Superficial origin of erythrocytic chalone in polycythemia in vitro]. / Poverkhnostnoe proiskhozhdenie epitrotsitarnogo keilona pri politsitemii in vitro.

It was shown in the culture of rat bone marrow cells in experimental polycythemia that the chalone activity of erythrocytic chalone considerably drops in the presence of phytohemagglutinin (PHA). The chalone inhibits the agglutinating activity of PHA with respect to bone marrow cells. Absorption of the chalone on the immobilized PHA leads to disappearance from it and of PAS-positive bands recorded electrophoretically and to a strong decrease in PAS-negative band intensity. Experiments with preliminary incubation of rat red cells before preparation of the chalone suggest that in the course of its preparation two polypeptides one of which is PAS-positive are released into the medium. It is suggested that the chalone includes superficial membrane proteins of red cells, possibly, in the form of a combination of PAS-positive and PAS-negative bands. Potential mechanisms of chalone release from the surface of cells and features of their action on the cells are discussed.