Biomedical subjects

G V Donchenko

Publications and source records attributed to G V Donchenko.

At least 55 records · Page 3Linked to original sources

PubMedDate not supplied

[Comparative study of the effect of alpha-tocopherol, its synthetic metabolite and ionol on dexamethasone-induced apoptosis in rat thymocytes].

alpha-Tocopherol was found to decrease the level of rat thymocytes DNA fragmentation and to increase the viability of these cells under apoptosis induction by dexamethazone. So the antiapoptotic role of this vitamin is suggested. In contrast to alpha-tocopherol synthetic antioxidant ionol and alpha-tocopherylacetate, contained only 6 carbon atoms in its isoprenoid side chain caused the cell death from necrosis. This process preceded the apoptosis stimulated by dexamethazone.

Animals↗

PubMedDate not supplied

[Antihypoxic effect of vitamin E and its derivative in rats under modeling of hypoxic conditions of different origin].

The increase of ubiquinone content in myocardial mitochondria and succinateubiquinone reductase activity in rat blood leucocytes under hypoxic hypoxia and acute microfocal myocardial damage [table: see text] have been shown. At the same time the succinateubiquinone reductase activity of rat myocardial mitochondria do not change substantially. We simultaneously observe the dramatic drop in NADH-ubiquinone reductase activity under experimental myocarditis. This fact demonstrates higher stability of succinateubiquinone reductase system and differences in metabolical processes under hypoxic conditions of different origin. All vitamin E derivatives studied demonstrate substantial antihypoxic activity, which is connected with increased animals' survivability, ubiquinone content in myocardial mitochondria and stabilization and leveling of succinateubiquinone reducatse activity in rat blood leucocytes. alpha-Tocopherolacetate with shortened to six carbon atoms side chain is the most effective in this respect. We discuss possible mechanisms for the realization of vitamin E and its active derivative's antihypoxic effect.

Animals↗

PubMedDate not supplied

[The functional characteristics of the inhibitory mediator systems in the brain synaptosomes of PP vitamin-deficient rats].

A decrease of the NAD and serotonin level in the brain of rats with PP hypovitaminosis is shown. NAD in concentration of 10(-6) M in vitro exerts a less pronounced inhibiting influence on the neuronal uptake of [14C]serotonin and [14C]GABA by brain synaptosomes of rats with PP hypovitaminosis. GABA content under such conditions increases as compared with the control and correlates with changes in the [14C]GABA uptake system.

Animals↗

PubMedDate not supplied

[Arachidonic acid metabolism and vitamin E].

Basing on data from literature vitamin E is considered for its possible effect on the exchange of arachidonic acid. It is supposed that vitamin E controls metabolism intensity of arachidonic acid by changing activity of phospholipase A2, cyclooxygenase and lipoxygenase.

Animals↗

PubMedDate not supplied

[Vitamin E and apoptosis].

The literature data concerning the participation of tocopherol in apoptosis are discussed. Acting as antioxidant this vitamin exerts a complex effect on apoptosis mechanisms. Its action on this process is caused by involvement of some different mechanisms transducing the apoptotic signal. Among them are caspase and Fas-receptor activation, sphingosine metabolism, processes carried out in nuclei and mitochondria and signal transduction pathways. The specific mechanisms connected with interaction of this vitamin with tocopherol-binding proteins may be also involved in this vitamin action.

Animals↗

PubMedDate not supplied

[Intracellular localization of thiamine-binding proteins in the liver and kidneys of rats].

The distribution of thiamine-binding and thiamine triphosphatase activity typical of thiamine-binding proteins was studied in intracellular structures of rats liver and kidneys. It was found that the fraction of microsomes has the highest rate of specific thiamine-binding activity amide fractions of subcellular structures that was isolated using differential centrifugation in the both organs. Hydrolysis of thiamine triphosphate (pH 7.4) was also extremely active in these structures. The results of our research allow to make a conclusion that subcellular structures precipitated as fraction of microsomes (endoplasmic reticulum and vesicled parts of plasma membranes) are the sites of the most probable localisation of thiamine-binding proteins of liver and kidneys.

Animals↗

PubMedDate not supplied

[Effect of alpha-tocopherol on apoptosis and necrosis of rat thymocytes induced by calcium ionophore A23187 in various concentrations].

It has been established that alpha-tocopherol prevented rat thymocytes apoptotic death induced by low concentration (250 nM) of calcium ionophore A23187. When necrotic cell death was induced high concentration (10 microM) of calcium ionophore A23187 alpha-tocopherol was able to alter necrosis to apoptosis. It was proposed that such effect can be explained by the ability of alpha-tocopherol to prevent the mitochondrial permeability transition--a key event in apoptosis and necrosis induction.

Animals↗

PubMedDate not supplied

[Effect of iodine and cobalt salts on content of biologically active substances in spirulina biomass].

Production technology of iodinized spirulina biomass at vertical panel airlifted photobioreactor has been developed. The influence of different concentrations of iodine ions at certain combinations with cobalt ions on iodine-accumulative properties of spirulina has been studied. It has been shown that it is possible to obtain spirulina biomass containing certain amount of organically bound iodine by varying cobalt and iodine ions combinations and by staged addition of ions to incubation medium. This technique of staged addition of iodine and cobalt salt allowed to adopt spirulina to their high amount in the incubation medium, to increase spirulina productivity during growth, and to produce biomass with large iodine content.

Bacterial Proteins↗

PubMedDate not supplied

[Increasing the effectiveness of thiamine by its administration together with methionine and vitamin E].

The influence of methionine and vitamin E, compounds intensifying thiol metabolism, on thiamine-phosphate level and thiamine-dependent dehydrogenase activity was studied in the liver of rats with varying thiamine providing: in case of its alimentary deficiency, and intensified thiamine consumption due to rat feeding with high-carbohydrate food. Methionine administration to vitamin B1-deficient rats led to a significant rise in thiamine-phosphate content and normalized alpha-ketoacid dehydrogenase acidity and non-protein SH-group level. Combined administration of thiamine with methionine and vitamin E increased the level of parameters studied. Methionine and vitamin E administered with thiamine intensified the regulatory action of thiamine on pyruvate dehydrogenase activity in the animals fed high-carbohydrate ration.

3-Methyl-2-Oxobutanoate Dehydrogenase (Lipoamide)↗

PubMedDate not supplied

[Viruses as the etiological factor of type 1 diabetes. Animal models].

Type 1 diabetes (TID) results from the destruction of pancreatic beta-cells. In spite of genetic pre-disposition, being the major component for the development of this type of diabetes, nongenetic factors also play an important role in the disease development. Among these factors viruses are implicated in the pathogenesis of TID. Basing on the literature data we have attempted to elucidate possible role of viruses in TID pathogenesis. Viruses may be involved in the TID pathogenesis in at least two distinct mechanisms. Firstly, viruses may trigger beta-cell-specific autoimmunity with or without direct infection of beta-cells. Secondly, viruses may directly infect and destroy beta-cells resulting in TID. Moreover viruses not only cause diabetes, but also may prevent from the disease in animals susceptible to diabetes. Further studies are necessary to understand the mechanisms of the pathogenesis of human virus-induced TID.

Animals↗

PubMedDate not supplied

[Effect of alpha-tocopherol and its derivatives on actinomycin D induced apoptosis of rat thymocytes].

The induction of rat thymocyte apoptosis by actinomycin D was associated with the increased caspase-3 activity and DNA fragmentation, the both effects were attenuated by alpha-tocopherol. Apoptosis was also decreased by alpha-tocopheryl acetate, but these suppressive effects were less than those of alpha-tocopherol. Tocopheryl quinone had no pronounced antiapoptotic effect. It was proposed that the difference in antiapoptotic effects of alpha-tocopherol derivatives is attributed to structure properties of the chroman head group and to the ability for scavenging reactive oxygen species but it is not excluded that antiapoptotic activity of alpha-tocopherol may exceed that of a mere antioxidant.

Animals↗

PubMedDate not supplied

[Cytotoxic effect of vitamin E short-chain derivatives on rat thymocytes].

It is established, that alpha-tocopherol, alpha-tocopheryl acetate and tocopheryl quinone with carbon lateral chains shortened to 6 atoms inhibited the viability of primary culture rats thymocytes in a dose-dependent manner. Absence of the DNA internucleosomal degradation side by side with cytosolic lactate-dehydrogenase outlet from the cells testifies to the benefit of necrotic way of thymocytes destruction. The outlet from cells of acid phosphatase, lysosomal marker enzyme, testifies to destabilization of lysosomal membranes by the researched compounds. The possible mechanism of cytotoxication of vitamin E short-chain derivatives in cell cultures is offered, namely: their high permeability through a plasmatic membrane allows to create inside the cells a concentration, sufficient for detergent-like rupture of the lysosomal membranes, that results in the entering of lysosomal enzymes in cytosol and destruction of cells by necrosis.

Animals↗

PubMedDate not supplied

[To the 20th anniversary of the Chornobyl accident study of vitamin status and provision with micro- and macroelements of limited groups of people at different time periods since the accident at Chornobyl nuclear power plant].

Results of the study of the provision with vitamins and some micro- and macroelements of limited groups of people, who suffered from the accident at the Chornobyl nuclear power plant (ChNPP), which have been carried out by Ukrainian and Russian scientists during various periods after the accident, are generalized in the paper. Persons which participated in liquidation of the accident and lived during the accident in the territory, adjoining to Pripyat (the Kyiv region, town of Slavutich), people which worked at the object "Shelter" and ChNPP were involved in the inspection. It was noted, that in 1-4 years after the ChNPP accident in blood of liquidators the biochemical parameters displaying security of their organism by vitamins A and B1, remain lower in comparison with the same parameters in a group of relatively healthy persons which were not affected by the accident (control), that testifies to stable metabolic disturbance in the organism of people under irradiation influence. Selective inspection of the vitamin status of ChNPP and object "Shelter" personnel in 1992 has shown, that provision with vitamins C, B1, B2, B6 of the overwhelming majority of these people (67-91%) are much below the norm. Deficiency of vitamins C, B1, B6, folate and selenium is also revealed in an organism of 50-90% of women and children living in Slavutich. Deficit of vitamins in most of persons was characterized by polyhypovitaminoses, that is a combination of several group B vitamins deficiency at simultaneously low provision with selenium, and in a part of women and children--by low amount of iron. The results of long-term complex studies by groups of authors give evidence on importance and urgency of formulation and execution of International program on optimisation of nutrition, micronutrition status and health among population of affected areas in Ukraine, Bielorus' and Russia.

Calcium↗

PubMedDate not supplied

[Vitamin E and its structural analogs in tuberculosis].

Efficiency of tocopherol, its analog with a shortened side chain as well as their quinons for tuberculosis was determined. All the studied compounds inhibited peroxide-formation processes in the liver homogenate and mitochondria. The vitamin E amount in the blood is considerably decreased in case of tuberculosis. The studied analogs increased its content and possessed a weak tuberculostatic but expressed antiedemic and antiinflammatory action. Administration of vitamin E in combination with isoniazid to sick animals had a favourable effect on the processes of tissue respiration and oxidative phosphorylation. If taking a sum of characters, tocopherol acetate with a shortened side chain is the most efficient of all the analogs under study for the tuberculosis therapy.

Animals↗

PubMedDate not supplied

[Functional-metabolic changes in the brain during various conditions of supplying the rat with vitamin PP].

Content of nicotinamide nucleotides, reception of NAD by synaptic membranes and the system of 14C-serotonin uptake and liberation in rat brain nerve endings were studied under various conditions of vitamin PP consumption. In PP hypovitaminosis binding of 14C-NAD was decreased in synaptic membranes as a result of alterations in capacity of receptor sites, which occurred simultaneously with low level of nicotinamide coenzymes in rat brain. These alterations led to deterioration of NAD modulating function in liberation of 14C-serotonin from synaptosomes. The data obtained suggest that functional activity of NAD-receptor system in synaptic membranes of rat brain depends on the rate of vitamin PP consumption. These results might be considered in clinical research when vitamin PP is used for treatment of various diseases.

Animals↗

PubMedDate not supplied

[Effect of benzodiazepines on NAD binding to synaptic membrane in the rat brain].

The receptor protein solubilized from synaptic membranes specifically binds [14C] NAD (dissociation constant--0.75 microM, capacity of binding sites--0.0125 nmol of metaid per 1 mg of protein). All the studied benzodiazepines (phenazepam, nitrazepam, clonazepam, flunitrazepam) are able to displace [14C] NAD from its receptor sites, the mixed type of inhibition being manifested. An inhibition constant for flunitrazepam, a ligand of benzodiazepine receptors, equals 10 microM. GABA promotes an inhibiting effect of benzodiazepines. It is supposed that neurotropic action of NAD is realized through the GABA-benzodiazepine complex of neuronal membranes.

Animals↗

PubMedDate not supplied

[Vitamin E, ubiquinone and ubiquinone-dependent enzymes in experimental myocarditis].

It is shown that a day after introduction of adrenaline which evokes experimental focal myocarditis the level of ubiquinone and vitamin E content in the myocardial mitochondria increases by 56.8 and 122%, respectively. Succinate-ubiquinone-reductase activity in mitochondria remains practically unchanged, while NADH-ubiquinone-reductase activity considerably falls. 5 days after the focal myocarditis reproduction the content of ubiquinone and NADH-ubiquinone-reductase activity of mitochondria return to the norm, while the vitamin E amount remains higher than in intact animals. 24h after adrenaline introduction the level of succinate-ubiquinone-reductase activity of blood leucocytes considerably grows. It is not normalized even on the 5th day after adrenaline administration. It is supposed that the level of this activity may be an index showing development of the focal myocarditis.

Animals↗

PubMedDate not supplied

[Changes in protein, lipid composition, DNA- and RNA- polymerase activity of the chromatin fraction and the nuclear matrix of the rat liver in hypovitaminosis E].

E-hypovitaminosis-induced antioxidant deficiency in rats causes changes in some properties of nuclear structures of the liver cells, i.e. fractions of transcriptionally active and repressed chromatin and nuclear matrix. Changes are found in the protein spectrum of the fraction of transcriptionally active chromatin and nuclear matrix. Lipids of transcriptionally active and repressed chromatin fractions may be peroxidated when this process is stimulated in the NADPH- and ascorbate-dependent systems. In antioxidant deficiency these processes are intensified in the fractions of repressed chromatin. E-hypovitaminosis leads to changes in the fatty acid spectrum of chromatin fractions which correlated with the shifts in the process of lipid peroxidation. Antioxidant deficiency produces changes in the activities of endogenous DNA- and RNA-polymerases in chromatin fractions and in the nuclear matrix. In the fraction of the transcriptionally active liver chromatin of E-deficient animals the endogenous total DNA-polymerase activity and the activity of DNA-polymerases alpha and beta decrease, while in the fractions of repressed chromatin the total RNA-polymerase activity increases. In E-hypovitaminosis the endogenous DNA- and RNA-polymerase activities in the nuclear matrix decrease. Addition of alpha-tocopherol to the preparations of the isolated nuclear matrix results in an increase of the DNA- and RNA-polymerase activities which is more vivid in preparations made of the E-hypovitaminous animal liver.

Animals↗