![[About Institute]](../../graphics/aboutins.gif)
The results of biochemical, biophysical and morphologic research have shown that the liver is the organ sensitive to the irradiation of animals by low radiation doses. For instance, in g-irradiation (0.5-2 Gy) a dose-dependent effect is observed in the structural changes of rat liver microsomal membranes which is mostly due to the increased microviscosity of the membranous lipid bilayer and the formation in it of areas of sufficiently high polarity.
The information on molecular kinetic properties of the enzymes from the animal heart muscle oxoglutarate dehydrogenase complex has been extended. The role of the oxoglutarate 2-oxo group and the positively charged arginine residue spatially distant from the active site is essential for the manifestation of 2-oxoglutarate dehydrogenase activity. The additive effect of oleate observed in decreasing oxoglutarate catalysis indicates the significance of unsaturated fatty acids in control of enzyme activity. Multiple forms of all the complex subcomponents arising due to the post-translation modification have been revealed.
The cariometric studies of the epithelial and lymphoid components of the thyroid gland in endemic and toxic goiters, adenoma and cancer of the thyroid gland have been used to develop the morphologic criteria of thyreopathology early diagnosis, and its role in cancer morphogenesis has been studied.
The experiments on permeabilized cells of the Ehrlich ascites carcinoma have shown that the stability of plasmatic membranes is due to the close relations between the mitochondrial bioenergy processes and the cytosolic CoA biosynthesis.
It has been found that the oxidation of oxy- and desoxyhemoglobin from human erythrocytes by nitrites gives rise to nitrogen oxide and S-nitroso-glutathione playing an important role in control of the blood flow. It has been shown that the formation of these compounds can explain the favourable physico-therapeutic effects of ultrasound on the animal body.
It has been established for the first time that chronic ethanol consumption induces considerable disturbances in the activity and isoenzyme composition of monoaminooxidase from neuronal and barrier brain structures which can be assessed as a mechanism of the alcohol central action. The high extent of individual variability and the dependence of the severity of alcohol liver injury on the dose and character of ethanol action have been demonstrated. Close correlations have been determined between the morphologic and biochemical markers in this process.
Experiments in anterior hypothalamic slices revealed the presence of GABA-receptors involved in the inhibitory control of the host thermosensitive neurons. Opposite effects of bombesin and its molecular fragments on neurons with the same type of temperature behavior were shown. An increase in afferent impulse activity in the vagus, splanchnic and lumbar splanchnic nerves at the highest body temperature during pyrogenal fever was found. In these conditions, changes in the fine structure of sympathetic ganglion neurons and adrenal microcirculatory bed occurred, and energy metabolism in the thyroid gland and adrenal cortex was activated.
Persons with cranial traumas showed a higher concentration of nerve growth factor, as compared to healthy persons. Changes in the kinetic parameters of phosphorescence fading in PC12 cell nuclear suspension under the influence of nerve growth factor and epidermal growth factor were found.
It was found that the initial period of experimental fever is characterized by hyperalgesia and systemic arterial hypertension, and, in the brainstem, by activation of serotoninergic processes mostly in the sensory regions of the brainstem and attenuation of inhibitory glycinergic mediation in brain structures that form efferent signals to sympathetic pregangionic spinal neurons (ventrolateral medulla oblongata).
It was first shown that application of nicotinamide before and biogenic stimulants (thymaline or solcoseril) after carcinogenic agent led to a decrease in induced oncogenic disorders and tumour formation. The highest antimutational effect during ionizing radiation was reached after combined protection by thymaline and solcoseril.
A short-term (10 min) ischemia of a small intestine segment was accompanied by a rise in the blood content of catecholamines, reflex enhancement of sympathetic efferent impulse activity in gastrointestinal nerves, and inhibition in cervical sympathetic nerve. With a view to correcting the functioning of neurogenically lesioned organs, a possibility of their directional regulation by different surgical and physical methods was studied. The large intestine was found to be a donor of nerves and vessels during organopexy.
An increase in the content of catecholamines and a decrease in the acetylcholinesterase activity in thymic nerve fibers that occurred 15 and 120 min after application of interleukin-1 was not accompanied by changes in the proliferative activity of lymphoid cells of the organ. The intensity of energy metabolism processes in the brain and liver under the influence of the cytokine increased later (one day after). In animals with initially high motor activity, lipopolysaccharide induced a decrease in behavioral responses both in normal conditions and with acoustic stimulation.
It is concluded that the tritium content in the atmospheric precipitations is fluctuating in significant limits and constitutes 30--100 and more tritium units in the water (1 unit = 0.118 Bq/l of water) not overpassing however the admissible concentrations for the water of open reservoirs (1.5·105 Bq/l of water). The tritium origin is considered mainly as the result of technogenic pollution of the Belarus' territory.
The study of process of radionuclides absorption by soils had shown that as large is the quantity of organic matter in soil as less is the scale of 137Cs absorption. At the removal of organic matter by thermic method the quantity of absorbed radiocaesium increases. The firmness of its fixation increases equally and it was confirmed in the experiments on desorption in the conditions of soil humus removal using the hydrogen peroxide. This is connected with the fact that the structure of soil mineral component is not disturbed at the mild humus removal and the organic substances which screen the energy-saturated absorption centers are removed simultaneously. By the same the possibility of radiocaesium ions fixation by the mineral part of soil increases.
It is established that on the terminal folds of rivers flowing through the radiocontaminated territories of Gomel and Magilyou regions, the mean 137Cs wash-out constituted 161--3,390 Bq/s, and for 90Sr -- 144--11,281 Bq/s in the summer period of 1996, not exceeding in average the analogous wash-out values of preceding years. As a rule, the wash-out of radionuclides increases by the flow of rivers. This is connected with the continuous supply of them from polluted areas of water collection.
It is shown that use of biologically active natural compounds (oxyhumate, hydrohumate) and synthetical sulphur-containing means of plant protection cause the decrease of 137Cs and 90Sr accumulation in generative organs of agricultural legumes (peas, lupine) against the background of stimulation of photosynthetical and biochemical processes of yield raising.
The chronic external (1 Gy) and internal (137Cs, 160 kBq) irradiation as well as their combined action is shown lead to significant changes in the reception of sex steroid hormones in hormone-dependent organs which persist in remote terms after the irradiation, especially at the combined irradiation. At the action of small radiation doses, this may be one of factors of disturbance of state of organs regulated with the participation of sex hormones.
It is established that the thyroid hypofunction caused by the mercasolil incorporation aggravates the disturbances of organism's endocrine function conditioned by the irradiation in small doses (0.5 Gy): thyroid hormones formation and their metabolism in periphery, reduction of cytoplasmic receptors of androgens and estrogens in testicles, uterus and other organs, b-adrenergic regulation and cardiomiocytes' adenilatcyclase activity decrease, calcium transport system change with reconstruction of conformation characteristics and lipotropic structures modifying calcium pump functioning what leads finally to lowering of heart contractions frequency, increase of the index of regulation systems tension and shift of vegetative balance to the side of sympathetic regulation and other disturbances.
Source: "Main Results of Fundamental Research. 1996--1997". Eds. F.A.Lakhvich and N.N.Kostyukovich. National Academy of Sciences of Belarus, Minsk, 1998.
 Academy |
| The NASB Presidium Information Server Links: | ||||
| About Academy • Organizations • Academy Activities • Other Sites • Full Index | ||||
|
History • Officers • Membership • Staff • International Relations • Academy's Prizes Departments • Institutes • R&D Activities • Research Programs • Conferences Legislation • Publications • Library • Museums • Archive • Publishing House |
![[NASB Home]](../../graphics/homebutton.gif){kind=small} Home |
![[Scientific Sites]](../../graphics/sciencebutton.gif){kind=small} Science |
![[Belarus Sites]](../../graphics/countrybutton.gif){kind=small} Country |
![[World Sites]](../../graphics/worldbutton.gif){kind=small} World |
[ Home | Science | Country | World ]