Lyotropic La-containing lamellar liquid crystals: phase behaviour, thermal and structural properties.

This paper provides the results of POM, DSC and XRPD methods characterizing the liquid crystalline behaviour, thermal properties and structural parameters of lyotropic systems based on a nonionic surfactant and lanthanum nitrate (La(3+)). The systems based on tetraethylene glycol monododecyl ether (C12EO4) and lanthanum nitrate have been demonstrated to form a lamellar phase. The concentration and temperature ranges of the existence of mesophases as well as thermodynamic parameters of phase transitions have been estimated. The structural parameters of the lamellar phase of the C12EO4/La(3+)/water systems have been determined using X-ray diffraction. The model of molecular packing in lamellar lanthanide-containing lyotropic mesophases was proposed for the observed patterns of structural parameters obtained at various water contents. NMR (1)H with a pulsed magnetic field gradient has been used to characterize molecular motions in the C12EO4/La(3+)/H2O systems with different water contents.

[On the mechanisms of formation of the serum structural macroportrait in subjects suffering fatal intoxication with narcotic and potent substances].

Intoxication with narcotic and potent substances was shown to lead to the development of specific features in the serum structural macroportrait. Peculiarities of profiles of low and high molecular weight substances and acoustic-mechanical impedance parameters in blood serum were identified in subjects with drug poisoning. It is demonstrated that streaking pattern in the central zone of a dehydrated serum droplet described in an earlier study of subjects suffering intoxication with narcotic and potent substances result from structural decomposition of immunoglobulins under effect of oxidative modification. The proposed technologies provide a basis for the development of a method for rapid determination of the presence or absence of intoxication with narcotic and potent substances.

[Application of the clinoid dehydration method in forensic medical expert examination of poisoning with narcotic and strong medicine preparations].

The method of clinoid dehydration of biological fluids along with pH measurement is shown to be suitable for the diagnosis of narcotic intoxication and poisoning with narcotic and potent agents. The data obtained by this and conventional methods are compared. Diagnostically significant signs of narcotic intoxication are deduced from the hemogram of a dry blood droplet and serum pH values.

[Plant genetic engineering in Monsanto company: from the first laboratory experiments to worldwide practical use].

The history of modern biotechnology of agricultural plants is briefly considered in the article. Methods of genetic transformation and regeneration of transgenic plants as well as the mechanisms of resistance of genetically modified plants to herbicides and pests are discussed. By the example of genetically modified varieties and hybrids there are shown the ways of solving the problem of weeds and pests. The questions of biosafety legislation in different countries are considered.

The effects of radiation and alkylating agents on chromatin degradation in normal and tumour lymphoid cells.

The dynamic of chromatin degradation was studied in thymocytes and LS/BL tumour cells. In permeabilised LS/BL cells, the rate of DNA degradation induced by endogenous calcium and magnesium-dependent endonuclease was approx. 25 times slower than in thymocytes. In LS/BL cells irradiation does not induce chromatin degradation. The alkylating agent TS 160 induced chromatin degradation in both LS/BL lymphosarcoma cells and thymocytes.

[The effect of irradiation and alkylating agents on chromatin breakdown in normal and malignant lymphoid cells]. / Vliianie oblucheniia i alkiliruiushchikh agentov na raspad khromatina v normal'nykh i malignizirovannykh limfoidnykh kletkakh.

Regularities of chromatin degradation in thymocytes and LS/BL tumor cells have been investigated. It has been shown that the rate of DNA degradation by Ca/Mg-dependent endonuclease in LS/BL tumor cells is 25 times lower than that in thymocytes, and radiation does not induce chromatin degradation. The alkylating agent TS 160 causes chromatin degradation in both LS/BL cells and thymocytes. In contrast to radiation TS 160 inhibits the endogenous chromatin degradation by Ca/Mg-dependent endonuclease in thymocytes.

[Electrophoretic analysis of the internucleosome fragmentation of DNA in irradiated thymocytes of rats]. / Elektroforeticheskii analiz mezhnukleosomnoi fragmentatsii DNK v obluchennykh timotsitakh krys.

Total DNA and DNA of chromatin degradation products obtained from rat thymocytes 6 h after irradiation with a dose of 10 Gy were separated electrophoretically. Relative shares of mononucleosomes and their oligomers were determined. Experimental distributions of DNA fragments differ from those calculated on the basis of the assumption of a random breakage of bonds between the nucleosomes.

[Thymidine excretion from thymocytes in irradiated and nonirradiated rats during endonucleolysis]. / Ekskretsiia timidina iz timotsitov obluchennykh i neobluchennykh krys v usloviiakh éndonukleoliza.

The concentration of free thymidine (dT), excreted from thymocytes of irradiated and nonirradiated rats, was determined after incubation of cells in various digestive buffers. The release of dT from thymocytes depended upon the rate of DNA fragmentation in conditions of chromatin endonucleolysis. The increase in the thymidine content, in conditions of chromatin endonucleolysis in buffers containing no calcium ions, was only noted in thymocytes of exposed rats: this was the consequence of chromatin DNA damages already available in these cells.

[Effect of metronidazole on the free thymidine content in the blood serum of irradiated mice]. / Vliianie metronidazola na soderzhanie svobodnogo timidina v syvorotke krovi obluchennykh myshei.

The influence of a radiosensitizer, metronidazole, on the free thymidine content of blood serum of irradiated mice was studied in aerobic and hypoxic conditions. A heated metronidazole solution (1 mg/g) was administered intraperitoneally 30 min before irradiation of animals with a dose of 3 Gy. Thymidine concentration in blood serum was determined by the radioimmunological technique. The influence of metronidazole on the level of thymidinemia was only noted in the animals exposed under hypoxic conditions.

[The level and immunochemical characteristics of fibronectin in the plasma of irradiated rats]. / Otsenka soderzhaniia i immunokhimicheskaia kharakteristika fibronektina plazmy obluchennykh krys.

The electrophoretic and immunoelectrophoretic methods were used to study fibronectin of blood plasma of intact Wistar rats and of those exposed to 1-10 Gy radiation. The increase in the fibronectin concentration 3 days after irradiation was a function of radiation dose. Possible mechanisms of the hyperfibronectinemia development involving mechanisms of endogenous proteolytic fragmentation of glycoprotein, the increase in the protein synthesis and complexation and inhibition of the rate of fibronectin degradation and elimination are discussed.

[Endonucleolysis of chromatin in thymocytes of irradiated and non-irradiated rats]. / Endonukleoliz khromatina v timotsitakh obluchennykh i neobluchennykh krys.

It was shown that in conditions optimal for Ca/Mg endonuclease, chromatin endonucleolysis in the nuclei and thymocytes occurs due to internucleosome fragmentation of DNA. Irradiation activates chromatin degradation in thymocytes washed by a buffer containing 0.25 M sucrose, 10 mM tris-HCl, pH 7.2, 3 mM MgCl2, and does not influence this process in thymocytes washed by 10 mM tris-HCl, pH 7.2, 3 mM MgCl2.

[Free thymidine in the blood serum of irradiated rats with different levels of cellular depletion of the thymus and spleen]. / Svobodnyi timidin v syvorotke krovi obluchennykh krys pri raznykh urovniakh kletochnogo opustosheniia timusa i selezenki.

The levels of the postirradiation thymidinemia, with an equal degree of the proceeding cell depletion of lymphoid organ tissues caused by the administration of dexamethasone and exposure of rats to 3 Gy radiation, markedly varied. Three days after the injection of the hormone, the organism responded to irradiation by an increase in the concentration of thymidine in blood serum in the same manner as intact animals did. The preirradiation with a dose of 3 Gy reduced sharply the ability of the organism to respond the repeated irradiation (after 3 days) by thymidinemia. There was a lesser increase in the thymidine concentration in the blood after the injection of dexamethasone than after irradiation inducing the same cell depletion of the thymus and spleen.

[A simple radioimmunological method of determining thymidine in biological fluids]. / Prostoi radioimmunologicheskii metod opredeleniia timidina v biologicheskikh zhidkostiakh.

A simple, sensitive and reproducible radioimmunoassay for determination of thymidine in biological fluids was developed. The technique is based on competition between 3H-thymidine and unlabelled thymidine for antithymidine antibodies. The cross-reactivity of structurally related compounds with the antibody was mostly negligible, except for deoxyuridine. The sensitivity of the assay was 10(-7) M. This radioimmunoassay may be used for measuring content of thymidine in blood serum and urine. A method for direct determination of thymidine in urine was not described before.

[Changes in the concentration of serum fibronectin in irradiated animals]. / Izmeneniia kontsentratsii syvorotochnogo fibronektina u obluchennykh zhivotnykh.

A study of the level of fibronectin in blood serum of Wistar rats at different times after gamma-irradiation (7.5 Gy) has demonstrated a considerable increase in its concentration after 3 days. This increase is a function of radiation dose absorbed (within the range from 1 to 10 Gy). The most pronounced changes are observed with serious and extremely serious forms of acute radiation sickness. The administration of cycloheximide 48 h after irradiation removes completely the increase in the level of blood serum fibronectin.