[The effect of electromagnetic radiation on the membranes of the sarcoplasmic reticulum]. / Vliianie élektromagnitnogo izlucheniia na membrany sarkoplazmaticheskogo retikuluma.

On the sarcoplasmic reticulum membranes has been shown that at temperature of Ca2(+)-ATPase activity change of dependence in the Arrhenius plot the microwaves (2450 MHz, specific absorption rate 12 w/kg) inhibit the ATP-hydrolase and Ca2(+)-transporting activity of Ca2(+)-ATPase. The effect of radiation exhibits within the narrow temperature range (approximately 1 degree C) and quantitatively corresponds to the decrease of Ca2(+)-ATPase activity caused by the decrease of temperature by 1.6 degrees C from 18 degrees C. The fluorescence intensity of naphthalene sulfonic probes reduces under the influence of microwaves at 18 degrees C.

[Effect of the conditions of preparing erythrocyte ghosts on their radiosensitivity]. / Vliianie uslovii polucheniia tenei éritrotsitov na ikh radiochuvstvitel'nost'.

Conditions are chosen in which radiosensitive and radioresistant erythrocyte ghost preparations could be obtained: this may be valuable in studying mechanisms of the distinctions observed.

[K+,H+ and Cl- fluxes across erythrocyte membrane irradiated with radio frequency electromagnetic fields]. / Issledovanie potokov K+,H+ i Cl- cherez membranu éritrotsitov, obluchennykh élektromagnitnym izlucheniem radiochastotnogo diapazona.

The effect of 460 MHz microwave radiation on the ion-transporting properties of the isolated rat erythrocytes was studied with the use of K+, H+ and Cl(-)-selective electrodes. In comparison with the control cells kept at 0 degree C the most significant changes were observed in the K+ transport system. Particularly, microwave radiation (specific absorbed rate 280 W/kg) caused an increased loss of K+ during treatment and 2-fold decrease in the rate of K+ efflux from the irradiated erythrocytes, when the latter were incubated in the isoosmotic, unbuffered sucrose. The same changes were observed when the erythrocytes were conventionally heated up to 39 degrees C for 20 minutes. It is concluded that high levels of microwave radiation cause temperature-induced changes of the membrane structure resulting in alterations in potassium transport across the membrane.

[Effect of electromagnetic radiation of radio frequency (340 and 800 MHz) on liposomes from dimyristoyl lecithin]. / Vliianie élektromagnitnykh izluchenii radiochastotnogo diapazona (340 i 800 MGts) na liposomy iz dimiristoilletsitina.

Using the liposomes prepared from dimyristoyl lecithin at temperature below that of phase transition, its was shown that the annealing of liposomes by 340- and 800-MHz microwave radiation required less integral heating of the samples, than it should be expected from the experiments on heating the samples in a thermostat.

[Mechanism of changes in irradiated thymocytes detected by anilinonaphthalenesulfonate]. / Issledovanie mekhanizmov izmenenii, obnaruzhivaemykh v obluchennykh timotsitakh s pomoshch'iu anilinonaftalinsul'fonata.

In experiments on rat thymocytes obtained 15 min, 2 h and 4 h after irradiation of animals with the dose of 10 Gy it was found that 15 min and 4 h following irradiation changes occurred in their membranes increasing the lifetime of the excited state of anilinonaphthalene sulfonate and hydrofobicity and viscosity of its microenvironment. The indicated parameters did not vary from the controls 2 h following irradiation. The analysis of the data obtained prompted a suggestion that the observed changes were associated with the structural rearrangements in the plasma membrane rather than with its destruction. Model experiments on irradiated thymocyte suspensions showed that there was a correlation between changes in the cell membrane and meabolic processes.

[Mechanism of change in the fluorescence parameters of pyrene and diphenylhexatriene in irradiated membranes]. / Issledovanie mekhanizmov izmeneniia parametrov fluorestsentsii pirena i difenilgeksatriena v obluchennykh membranakh.

The erythrocyte ghosts were irradiated with doses of 100 to 1000 Gy. The fluorescence intensity and the lifetime of the excited state of pyrene and diphenylhexatriene were shown to decrease. The analysis of the results obtained has demonstrated that the changes in the fluorescence parameters of these probes are related to the enhanced dynamic probe quenching, the quencher being placed in water or the water itself being a quencher.

[Effect of ionizing radiation and Fe2+-induced peroxidation on the lipid phase of erythrocyte membrane preparations]. / Vliianie ioniziruiushchei radiatsii i perekisnogo okisleniia, indutsiirovannogo Fe2+, na lipidnuiu fazu preparatov éritrotsitarnykh membran.

The fluorescent probes, perilene and diphenyl hexatriene, were used to study changes in the lipid phase of erythrocytic ghosts induced by ionizing radiation (100-1000 Gy) and lipid peroxidation initiated by Fe2+ (5-100 microM). Both of the factors were shown to bring about similar changes in the membrane, that is, an increase in the viscosity of the probe localization sites and a decrease in diphenyl hexatriene fluorescence intensity. During the postirradiation incubation of the exposed membranes they were additionally damaged whereas upon peroxidation, most of the changes occurred after 15-min incubation with Fe2+.

[Thymocytes of irradiated rats studied using naphthalenesulfonic probes]. / Izuchenie timotsitov obluchennykh krys s pomoshch'iu naftalinsul'fonovykh zondov.

The fluorescence intensity of 1.8-aniline naphthalene sulfonate (ANS) and 2.6-toluidine naphthalene sulfonate (TNS) introduced into irradiated rat thymocytes reached maximum 15 min and 4 h following irradiation (1-20 Gy). The parameters of 1.8-ANS binding to membranes did not contribute markedly to the effect observed.

[Study of the structural changes in irradiated erythrocyte membranes using 2,6-toluidinonaphthalene sulfonate]. / Issledovanie strukturnykh izmenenii v obluchennykh éritrotsitarnykh membranakh s pomoshch'iu 2,6-toluidinonaftalinsul'fonata.

It was shown that 2,6-tolyidinonaphthalene sulfonate (2,6-TNS) is localized mainly at the bilayer-water border of the erythrocytic membranes. Under the effect of gamma-radiation the rearrangements occur in the membrane which bring about changes in the distribution of the probe between the membrane and the medium. The lifetime of the excited state of 2,6-TNS after irradiation varies slightly.

[Effect of pulse electromagnetic radiation on erythrocyte ghosts]. / Vliianie impul'snogo élektromagnitnogo izlucheniia na teni éritrotsitov.

The pulse microwave radiation has been shown to increase the fluorescence intensity of 2-toluidinonaphthanene-6-sulfonate (2,6-TNS) and 1-anilinonaphthalene-8-sulfonate (1,8-ANS) built-in membranes of erythrocyte ghosts. In experiments with 2,6-TNS a frequency dependence of the effect of microwave radiation with maximum within the frequency range of 55-65 Hz has been found. It is suggested that the changes registered with fluorescent probes are induced by mechanical oscillations generated by the pulse microwave radiation.

[Study of the aggregation of membrane proteins of erythrocyte ghosts using SDS-PAAG electrophoresis]. / Izuchenie agregatsii membrannykh belkov tenei éritrotsitov s ispol'zovaniem élektroforeza v DDS-PAAG.

Using the method of electrophoresis in SDS-PAAG the authors showed a diminution of proteins of bands I + II (spectrins) and III (major integral protein) after irradiation of erythrocyte ghosts with doses of 50 to 1000 Gy. We failed to ascertain that radiation-induced lipid peroxidation is involved into membrane protein aggregation. Among the radiolysis products, OH-radicals were shown to contribute markedly to the radiation effect observed.

[Inductive-resonance energy transfer between chromophores localized in different parts of irradiated and nonirradiated erythrocyte ghosts]. / Induktivno-rezonansnyi perenos énergii mezhdu khromoforami, lokalizovannymi v raznykh uchastkakh obluchennykh i neobluchennykh tenei éritrotsitov.

A study was made of the inductive-resonance energy transfer between chromophore pairs, tryptophan--pyren, tryptophan--1.8-anilinonaphthalene sulfonate (ANS), puren--1.8-ANS, diphenylhexatrien--ethidium, and 1,8-ANS--ethidium, in irradiated (250 Gy) and nonirradiated preparations of erythrocytic membranes. The radiation--induced decrease in the energy transfer was noted in the pairs in which one of the chromophores was localized in a lipid phase. On the basis of the data obtained it is suggested that irradiation of membranes causes the lesions in them which lead to a reduction of the effective thickness of a hydrophobic part of the lipid bilayer.

Effects of microwave radiation (340 and 900 MHz) on different structural levels of erythrocyte membranes.

By use of fluorescence probes 1-anilinonaphthalene-8-sulfonic acid, 2-toluidinylnaphthalene-6-sulfonate, pyrene, perylene and chemical label phosphatidylethanolamine 2,4,6-trinitrobenzele sulfonic acid, the effect of microwave radiation on the erythrocyte membrane was studied. The studies with the fluorescence probes were carried out on erythrocyte ghosts and with 2,4,6-trinitrobenzene sulfonic acid on whole erythrocytes. The fluorescence was measured during irradiation of the membranes with 340-MHz microwaves at an SAR of 100 W/kg. Trinitrophenylation of phosphatidylethanolamine from whole erythrocytes was performed simultaneously with microwave irradiation at 900 MHz (10 mW/cm2). It was shown that the microwave field decreased lipid viscosity, altered the structural state of lipid-protein contact regions, and decreased the protein shielding of lipids. These changes corresponded to those produced by thermal action of microwaves.

[Structural changes in erythrocyte ghosts after irradiation and the initiation of lipid oxidation detectable using 2,6-TNS and fluorescamine]. / Strukturnye izmeneniia v teniakh éritrotsitov posle oblucheniia i initsiatsii okisleniia lipidov, obnaruzhivaemye s pomoshch'iu 2,6-TNS i fluoreskamina.

It was shown on erythrocyte ghosts that the parameters of fluorescence of 2,6-toluidine-naphthalene-sulfonate (2,6-TNS) and fluorescamine undergo similar changes after irradiation. After a dose of 100 Gy the equally effective concentrations of Fe2+ were 1-5 microM and 50-100 microM with regard to changes in the rate of fluorescence of fluorescamine and 2,6-TNS, respectively, and greater than 100 microM with regard to fluorescence anisotropy.

Effect of secondary radiation produced by 70 GeV protons on DNA of mammalian cells.

It is shown that the RBE of the 70 GeV proton secondary radiation for the induction of single-strand break is 1.6-7.6 in Chinese hamster fibroblasts and 1.04-3.8 in limphoid cells and for the lethality of Chinese hamster cells 1.14-1.7. The RBE value increases with decreasing dose of the secondary radiation. On post-irradiation incubation of mammalian cells at 37 degrees C, single-strand breaks induced by the secondary radiation are repaired with the sane time course as those induced by gamma-rays. In our earlier works we have made an attempt to estimate the biological efficiency of radiation generated by the 70 GeV protons on bacteria, phage T4 and Vicia faba beans. The obtained values of the relative biological efficiency (RBE) of this radiation varied between 1.4 and 5.5, depending on the object, criterion of estimation, times of registration and other experimental conditions. The aim of the present work is to estimate the biological efficiency of synchrotron radiation by its effect on mammalian cells.

[Action of secondary radiation from 70-Gev protons on the cellular DNA of mammals]. / Issledovanie deistviia vtorichnogo izlucheniia ot protonov 70 Gév na DNK kletok mlekopitaiushchikh.

A study was made of the effect of secondary radiation of 70 GeV protons on DNA of Chinese hamster cells. With a reference to fibroblast DNA, lymphoid cell DNA, and the lethal effect of radiation on the survival of Chinese hamster cells the RBE was 1.6-7.6, 1.1-3.8 and 1.14-1.7, respectively. DNA breaks were repaired to an equal level after exposure to secondary radiation from the accelerator and gamma-radiation from 60Co in equally effective doses.

The effect of ionizing radiation on tryptophan fluorescence of thymocyte and erythrocyte plasma membranes.

The effect of ionizing radiation on tryptophan fluorescence of thymocyte and erythrocyte plasma membrane preparations was studied. The intensity of tryptophan fluorescence decreased after applying radiation doses up to 15 Gy. The radiosensitivity of thymocyte membranes appeared to be higher than that of the erythrocyte ghosts. Tryptophan radiolysis did not significantly contribute to the effects of radiation. The fraction of tryptophan residues accessible for quenching by I- decreased from 0.87 in the untreated membranes to 0.63 and 0.49 in membranes after doses of 10 and 250 Gy, respectively. The effective quenching constant and the tryptophan fluorescence polarization increased after irradiation. The mechanisms producing these radiation-induced changes are discussed.

[Tryptophan fluorescence of erythrocyte ghosts following irradiation and Fe2+ initiation of lipid peroxidation]. / Issledovanie triptofanovoi fluorestsentsii tenei éritrotsitov posle oblucheniia i initsiatsii perekisnogo okisleniia lipidov Fe2+.

It was shown that under the effect of Fe2+-initiated lipid peroxidation and ionizing radiation tryptophan fluorescence parameters (i.e. intensity and polarization) were subjected to similar changes. Shortly (15 min) after irradiation no changes were observed in the level of products reacting with thiobarbituric acid. It is concluded that the process and products of lipid peroxidation do not markedly contribute to the postirradiation alteration of tryptophan fluorescence. At the same time additional postirradiation damages to proteins can be attributed to activation of lipid peroxidation.