It has been found that under the action of oxygen free radicals the thiamine is transformed to hydrophobic thiochrome and oxodihydrothiochrome which are effective antioxidants. The oxidation of erythrocyte oxyhemoglobin and deoxyhemoglobin by nitrites revealed for the first time the formation of nitrogen oxide and nitrosoglutathione -- the relaxation factors of blood vessels.
It has been shown that the structural changes initiated by aldehyde products of lipid peroxidation in the microsomal membrane resulting in conversion of cytochrome P-450 into the inactive form are due to changes in the membrane rigidity profile and depend on the extent of hydrophobicity of the corresponding aldehyde and its localization in the membrane. The experiments on plasma membranes of the Ehrlich ascites carcinoma have demonstrated a membrane protective effects of pantothenic acid derivatives, CoA biosynthetic precursors.
Relationships have been revealed between the changes in the levels of glucosuria and pentosuria in experimental diabetes mellitus which enable one to use pentose metabolism as a factor of diagnostic, prognostic and treatment significance in insulin deficiency.
New mechanisms have been found for implementation of taurine biological activity in brain structures with different functional and metabolic orientation which are due to the activation of the dopamine and inhibition of the serotonine systems as well as to the imbalance of the inhibitory and excitatory neurotransmitters.
The experiments in vivo using newly synthesized hydrohythiamine derivaties have been carried out to obtain new data on a possible control by oxypyrimidine derivatives of the activity of principal vitamin B1-dependent enzymes. The role of intramolecular changes in the effect of these compounds on thiamine derivatives has been evaluated.
It was found in experiments in hypothalamic slices of guinea pigs that some neurons of this brain structure precisely set to the brain temperature possess intrinsic thermosensitivity independent of synaptic activity. The prolonged exposure to high temperatures (37-39 C during 4--6 days) leads to ultrastructural changes in the choroid plexus of the lateral ventricles of the cat brain, which indicates the development of pathological alterations is this region. Experiments with long- and short-term combined action of thermal and emotional factors revealed changes in the heart and lungs which are characterized by depletion of catecholamines, energy metabolism enzymes and ultrastructural disturbances. The data obtained reveal the mechanisms of disorders of neurohumoral regulation under the influence of stress factors of different nature.
The data were obtained indicating that a decrease in the catecholamine level in the gastric wall, an increase in vascular permeability, mucosal hemorrhages at early stages of experimental ulcerogenesis are due to inhibition of sympathetic efferent impulse activity in gastroduodenal nerves.
The neuronal groups of the caudal ventromedial and ventrolateral medulla were found to be links of the vestibulosympathetic reflex arc.
It is found that the nerve growth factor attenuates the lesioning effect of hydrogen peroxide on some clonal cell lines, synaptic transmission in sympathetic ganglia and prevents a reduction of ribo- and deoxynuclease activity in splenic and thymic tissues induced by X-radiation of animals at 12.9 mCoul/kg.
Fibers of the muscle plate of the colonic mucosa were found to regenerate in conditions of colon pexy to the ileum.
It was discovered that an important factor determining the radionuclides mobility in soil is the formation by 137Cs with humus soils substances of heteropolar salts which are more stable than 90Sr connections with humic and fulvic acids causing 90Sr mobility increase as compared with 137Cs in soil complex.
It was registered that chronic irradiation in small doses: a) causes in nearest and remote terms the disturbance of relations of vasoconstructive and vasodilating effects and diminishes the resistance of cardiovascular system to the injuring action of massive doses of catecholamines; b) exhausts the potential possibilities of immunocytes, conditioning the decrease of immune system response to specific antigenes; c) leads to the decrease followed by exhaustion of antioxidant system activity together with the accumulation of lipids peroxidation products in blood; d) causes the development of early edematous-distrophic changes in respiratory section of lungs with the macrophages quantity decrease, indicating the inhibition of defence functions in lung tissue; e) causes the disturbance of cytoplasmatic and nuclear reception of sexual steroid, glucocorticoid and thyroid hormones, the change of pancreas beta-cells function with insulin content decrease in pancreatic islands in the neurohormonal regulation system, testifying the discoordination of various regulation mechanisms in the irradiated organism.
The radiomodificatory properties of a number of preparations of natural origin (lactic acid bacilli preparation on the basis of Bifidobacterium adolescentis 91-BIM, preparation on the basis of mycelium extract of Schizophyllum commune) were revealed, which promote the blood leukogramme normalization, the improvement of a number of immunological indices and the optimization of functioning of reception systems of steroid and thyroid hormones in the conditions of acute and chronic irradiation. The mentioned preparations decrease the commune, pre- and post-implantation mortality.
Source: "Main Results of Fundamental Research.1994". Eds. A.M.Goncharenko and N.N.Kostyukovich. Academy of Sciences of Belarus, Minsk, 1995
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