Èçäàòåëü Èíñòèòóò ôèçèîëîãèè ÍÀÍ Áåëàðóñè, Ìèíñê, Ðåñïóáëèêà Áåëàðóñü
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ÍÎÂÎÑÒÈ ÌÅÄÈÊÎ-ÁÈÎËÎÃÈ×ÅÑÊÈÕ ÍÀÓÊ Èçäàòåëü Èíñòèòóò ôèçèîëîãèè ÍÀÍ Áåëàðóñè, Ìèíñê, Ðåñïóáëèêà Áåëàðóñü |
Summary: Age-related cognitive dysfunction has been linked to deficits in cholinergic and noradrenergic projections to the cortex. The role of these neurotransmitter systems in the regulation of cortical receptive fields suggests that functional disruption of the balance of excitatory and inhibitory modulation could contribute to impairments in cortical information processing with ageing. In the present study, age-dependent changes in the proportions of excitatory and inhibitory responses of somatosensory cortical neurones to iontophoretic application of acetylcholine and noradrenaline were investigated by recording extracellular unit activity in 2-3 months old and 14-15 months old Sprague-Dawley rats. In young rats, acetylcholine evoked equal proportions of excitatory and inhibitory responses at low ejection currents and an increased proportion of excitatory responses at higher currents while the effects of noradrenaline were predominantly inhibitory. Fewer neurones were sensitive to noradrenaline in the older rats. In the older rats, the inhibitory responses to acetylcholine at low ejection currents, and to noradrenaline, were significantly reduced while the number of excitatory responses to acetylcholine and noradrenaline were not significantly changed. Therefore, the proportion of inhibitory responses relative to excitatory responses was reduced in the older rats. These findings indicate an age-dependent imbalance of mechanisms underlying excitatory and inhibitory modulation of cortical neuronal activity by acetylcholine and noradrenaline.
Lukashenko T.M., Soltanov V.V.
Changes in the neuronal activity in the bulbar reticular formation after application of lipopolysaccharide E.coli to the small intestine of vagotomized rats. pp. 15--18
Summary: In acute experiments on thiopental sodium-anesthetized (70 mg/kg) rats, it was found that application of 10 µg lipopolysaccharide (LPS) to the jejunum of vagotomized rats led to a transient decrease in the total firing rate of neurons of the bulbar reticular formation, whereas infusion of the toxin to the ileum was accompanied by a significant biphasic increase in the firing rate. The effects emerged at 15 and 35 min of recording. It is concluded that, besides the vagus nerves, the information about an increased content of endogenous LPS in the small intestine is transmitted by spinal àfferent fibres, and largely from receptors of the terminal ileum.
Soltanov V.V., Halavach M.V.
Humoral modulation of activity of sympathetic efferent fibers after infusion of adenosine into the small intestine. pp. 19--24
Summary: In acute experiments on white rats (thiopental sodium anesthesia, 70 mg/kg, intraperitoneally) in conditions of extrinsic denervation, it was found that adenosine injected into the jejunum produced a long (1.5 h and more) reflex weakening of sympathetic efferent activity in superior mesenteric nerves. The opposite effects, but short-term (15-20 min), were observed after application of adenosine solution on the mesentery of the small intestine.
Shishkova M.K., Semenenya I.N., Ponomarev V.V.
Progesterone, thyroid hormones, and cortisol in liquor of subfebrile patients. pp. 25--27
Summary: Studies on the content of progesterone, thyroid hormones, and cortisol in cerebrospinal fluid of patients with prolonged subfebrility that had emerged under residual effects of neuroinfection revealed an increased level of progesterone, a decreased cortisol/progesterone ratio and lowered concentrations of triiodothyronine and thyroxine, which may play a substantial role in the mechanisms of development and maintenance of subfebrility.
Mardas D.K.
Influence of high temperature on the activity of proteinase inhibitors and concentration of corticosterone and iodine-containing thyroid hormones in blood of rats. pp. 28--33
Summary: It was found that high temperature exposure led to an increase in the activity of the proteinase inhibitor alpha-2-macroglobulin simultaneously with activation of the adrenal cortex and a decrease of the synthesis of thyroid hormones, T3 in particular. An enhanced activity of these systemic regulators, with a decrease in T3, may be a manifestation of a higher activity of mechanisms integrating the action of the functional systems of the organism during heat stress.
Stepanova N.A.
Participation of nitric oxide in the mechanisms of the influence of tri- and tetraiodothyronine on the detoxication processes and body temperature during experimental fever. pp. 34--39
Summary: In experiments on rats and rabbits it was established that action of LPS in the organism led to the activation of the hypophysis -- thyroid system, lipid peroxidation, detoxication processes and also to the elevation of body temperature. Preliminary injection of NO-synthase inhibitors (L-NNA, L-NAME) diminished the febrile response to endotoxin, prevented activation of the detoxication function of the liver and hypophysis -- thyroid system. Hyperthyrosis was accompanied by activation of the detoxication processes and a rise in body temperature. Inhibition of the NO-synthase activity attenuated the development of characteristic changes in the detoxication function of the liver and heat exchange processes under the action of exogenous triiodothyronine.
Bulhak A.A., Mrochek A.G., Gourine A.V.
Polymorphonuclear leukocytes in myocardial reperfusion injury. pp. 40--45
Summary: Reperfusion of ischaemic myocardium can induce irreversible reperfusion injury with manifestation of increasing infarct size along with its positive effect. Coronary flow restoration is accompanied by acute inflammatory reaction which includes activation and infiltration of myocardium by polymorphonuclear leukocytes what is supposed to play crucial role for the endothelial dysfunction progression and development of no-reflow phenomenon. Verapamil in dose 0.5 mg/kg decreased infarct size and myeloperoxidase activity, the marker of polymorphonuclear leukocytes infiltration, in the ischaemic myocardium in coronary artery ligation rat model when it was given at 35 min of 40 min ischaemia within 10 min. Verapamil in dose 0,1 mg/kg and precursor of nitric oxide L-arginine in dose 200 mg/kg did not influence on myeloperoxidase activity in the ischaemic myocardium along with their cardioprotective effect. These results indicate that activation and infiltration of myocardium by polymorphonuclear leukocytes do not take part in irreversible myocardial reperfusion damage and do not play crucial role in development of no-reflow phenomenon.
Kalunov V.N., Chaplinskaya E.V., Zhitkevich T.I.
The content of nerve growth protein in blood plasma of donors and chronic bronchitis patients. pp. 46--49
Summary: In patients with chronic bronchitis (n = 10) the plasma level of b-nerve growth factor changes at different stages of the disease, i.e. it decreases in the acute phase (to 284.00 ± 74.18 pg/ml as against 381.69 ± 166.82 pg/ml in control (n = 13)) and recovers in the course of treatment (to 417.00 ± 58.46). The increase in the circulatory content of the nerve growth protein in patients after the therapy may result from decompression of the immune part, the functions of which may be inhibited during a lasting disease.
Summary: The organization of tela submucosa of the human large intestine was studied using electron microscopy. Among multiple collagen fibres, there were electron-dense collagen bands running between the mucosal and muscular layers of the intestine. Collagen bands were also detected in connective tissue layers of the muscular membrane. The pattern of the distribution of collagen bands in tela submucosa indicates their role as an anchor-type linking factor between the mucosal and muscular layers of the gut wall. An analogous role is played by collagen bands in the muscular layer where they form the supporting frame of the intestinal wall. An adequate apposition of tela submucosa and muscular layer is an indispensable condition to form intestinal anastomosis with the use of layer-by-layer continuous inverted suture.
Summary: The possibility of simplification of thiamine triphosphatase (ThTPase) activity measurement by the amount of thiamine diphosphate was shown in the present study. To this end, the kinetics of ThTP hydrolysis at 100°C in water solution as well as the inhibition of bovine ThTPase by inorganic phosphate (Pi) were studied. The ThTP hydrolysis reaction was revealed to have the pseudo-first order, the rate constant being 0.0068 min-1. Pi inhibited the enzyme by a purely mixed type with the inhibitory constant of 2.7 mM. Based on these results, we propose to stop the ThTPase reaction by boiling or, that is preferably, adding a 4-fold excess of 0.5 M Na-phosphate buffer, pH 6.8, instead of using trichloroacetic acid. By the modified method, the import of denatured cytosolic ThTPase into bovine mitochondria in vitro was demonstrated.
Pronko S.P., Zimatkin S.M.
Ethanol metabolism in mice with genetically specified deficiency of catalase and cytochrome P450 E1. pp. 64--67
Summary: In the present study we examined the capacity of brain homogenates to oxidize ethanol through a catalase and cytochrome P450-dependent system, using the genetic strains of acatalasemic mice (IACAT), mice with genetically specified deficiency of cytochrome P450 2E1 (ICYP2E1KO), double mutants with genetic deficiency of both catalase and cytochrome P450 2E1 (F3DKO) and control mice (C3H). Acetaldehyde production from ethanol and ALDH activity in homogenates of their perfused brains were measured using gas chromatographic methods. The accumulation of ethanol-derived acetaldehyde in brain homogenates incubated for 30 min in the presence of 50 mM ethanol was the highest in the control group. The lowest rate of ethanol oxidation was observed in F3DKO mice (P < 0.01). The level of ethanol oxidation by brain tissue in vitro was significantly lower in F3DKO mice as compared to acatalasemic animals. Preincubation of homogenates with aminotriazole (catalase inhibitor) significantly reduced the acetaldehyde accumulation in control animals (P < 0.01). Preincubation of homogenates with diallyl sulfide (CYP2E1 inhibitor) also significantly reduced the acetaldehyde accumulation in control animals (P < 0.05). These experiments suggest that CYP2E1 as well as catalase can play an important role in ethanol metabolism in the brain.
Lapshina E.A., Domanski A.V., Zavodnik L.B.,. Zavodnik I.B.
Lysis of human red blood cells induced by hypochlorous acid. Effect of organic hydroperoxide and nitrite. pp. 68--74
Summary: Effects of organic hydroperoxide and nitrite on red blood cell damage induced by hypochlorous acid were studied. Hypochlorous acid induced oxidation of intracellular components and cell lysis. The oxidants nitrite and organic hydroperoxide (t-BHP), increased the damage induced by hypochlorous acid and led to new oxidative reactions. A direct interaction of hypochlorous acid and (t-BHP) in human erythrocytes was demonstrated using chemiluminescence.
Nadolnik L.I., Niatsetskaya Z.V., Vinogradov V.V.
The effect of single external g-radiation exposure on thyroperoxidase activity of the rat thyroid. pp. 75--78
Summary: We studied the effect of single external radiation exposure on thyroperoxidase (TPO) activity of the rat thyroid. For the first time it was shown that a single 0.25-5.0 Gy gamma-irradiation of rats induced a dose-dependent inhibition of TPO by 24.1-54.1% after 24 hours. The TPO activity decreased by 21.5–31.1% and 41.2-52.8%, also after 1 month and 1 year, respectively, indicating a pronounced sensitivity of the thyroid to irradiation. An increase in the concentration of the reactive oxygen species (O2- and H2O2) and toxic products of lipid peroxidation in the cells, and injury of thyrocyte genome (a decrease expression in the TPO mRNA gene) considered: as mechanisms of radiation-induced inhibition of thyroperoxidase.
Brasko N.V., Zavodnik L.B, Belanovskaya E.B., Buko V.U.
A combined iron and g-irradiation effect on free radical processes and liver texture in rats. pp. 79--85
Summary: It has been demonstrated that administration of carbonyl iron caused a moderate dose-dependent liver injury, accompanied by inflammatory changes and cytolysis in the high dose case. Simultaneously, LPO activation under the influence of g-irradiation was found in animals treated with the high iron dose, which may be due not only to the antioxidant system state, but also to the iron ion saturation of tissues.
Shpak G. A.
Early metabolic response of PC12 cells to polypeptide growth factors under heat shock. pp. 86--91
Summary: Nerve growth factor (NGF) and epidermal growth factor (EGF) were shown to activate endogenous phosphorylation of proteins (EPP) and the transport of glucose, alanine (without additivity) and leucine and uridine (additively) in PC12 cells. Heat shock largely inhibited EPP and the uptake of uridine, while NGF and EGF not only restored but also stimulated the processes. Thus, their interaction is both synergic and antagonistic. Despite that, the two bioregulators effectively maintain the survival of PC12 cells.
Summary: Rapid block of excitatory postsynaptic potentials, evoked by a paired-pulse stimulation of the Shaffer’s collaterals, in the CA1 region of the hippocampus has been found during perfusion of the hippocampal slices with the media containing ibotenic acid in 10-4--10-5 Ì concentration. After the end of perfusion, excitatory postsynaptic potentials have been restored, while their mean amplitude hasn’t reached the control (initial) level, i.e. toxic effect has been observed. Long-term increase in amplitude of excitatory postsynaptic potentials in the CA1 region has been found after perfusion of the hippocampus with media containing ibotenic acid in 10-6--10-8 Ì concentration.
Ioskevich N.N., Moiseenok A.G.
Pantenol as a remedy in prevention and treatment of reperfusion and reoxygenation syndrome in the lower extremities. pp. 96--102
Summary: The article considers possible methods of medical treatment and prevention of the reperfusion and reoxygenation syndrome complications in patients with lower extremity obliterating atherosclerosis who underwent reconstructive operations on the arterial femoral-popliteal-tibial segment. The efficacy of a complex therapy of this syndrome, according to the indices of oxygen transport blood function, with inclusion of Pantenol injections was shown. A correlation between medical correction of the postischemic reperfusion-reoxygenation syndrome and the stage of the initial lower extremity ischemia is emphasized.
Summary: The paper is a review of the literature characterizing free radical processes in trematodes, cestodes, nematodes and at their hosts. Helminths are able to produce antioxidant protection enzymes and nitric oxide synthetase. During invasions, the host shows an increased production of free radicals, activation or depression of the activity of antioxidant protection components which damage not only parasitic but also own host cells. Most hazardous are the mutagenic mechanisms of host genome damage under influence of free radical processes.
Kraskovsky G.V., Terpinskaya T.I., Mironova G.I., Manina E. Ju., Rosetskaya S.D.
The effect of immunization by an association of non-homologous oncotolerogen and adjuvant in the latency of urethane-induced tumour growth in lungs of mice. pp. 111--115
Summary: An association of factors: cross-reacting non-homologous oncotolerogen + adjuvant (egg albumin) acts as antioncotolerogen - during immunization in the latency of urethane-induced cancer growth and induces immunological response directed against cancer anergy and tumor growth (reduction of tumors in lung per mouse by 46.9%, that is 1.75 times (P < 0.05) less than in only cancerogen urethane control).
Suleymanoglu E.
Molecular phylogenetics and functional evolution of major RNA recognition domains of recently cloned and characterized autoimmune RNA-binding particle. pp. 116--126
Summary: Heterogeneous nuclear ribonucleoproteins (hnRNPs) are spliceosomal macromolecular assemblages and thus actively participate in pre-mRNA metabolism. They are composed of evolutionarily conserved tandemly repeated motifs, where both RNA-binding and protein-protein recognition occur to achieve cellular activities. By yet unknown mechanisms these ribonucleoprotein particles are targeted by autoantibodies and hence play significant role in a variety of human systemic autoimmune diseases. This feature makes them important prognostic markers in terms of molecular epidemiology and pathogenesis of autoimmunity. Since the ribonucleoprotein (RNP) domain is one of the most conserved and widespread scaffolds, evolutionary analyses of these RNA-binding domains can provide further clues to disease-specific epitope formation. The study presents a sequence comparison of RNA-recognition regions of recently cloned and characterized human hnRNP A3 with those of other relevant hnRNP A/B-type proteins. Their implications in human autoimmunity are particularly emphasized.
Summary: The data of own study of plasminogen molecule conformation, lability of its tryptophan-containing sites (including a comparative biochemical aspest) and functional properties of this molecule (involvement in reactions of generation and transformation of active oxygen species) are generalized. Literature data on a chemical composition of plasminogen molecule; its primary, secondary, tertiary structures; a character of the structure changes after zymogen transformation to plasmin; a peculiarities of zymogen interactions with small-molecular ligands and ligands of protein nature; the different sites of such interactions (lysine-binding, benzamidine-binding, interactions of carbohydrate residues) as well as nature of molecular heterogeneity of this zymogen molecule are discussed.
Nichelmann M.
What is the optimum temperature for animal keeping: a synopsis of own experiments. pp. 147--156
Summary: The optimum temperature for keeping of domestic animals must be characterised by a minimum of thermoregulatory heat production and therefore by an optimum of food convsumption rate and optimal satisfaction of all demands and by maximal wellness of the animals. The pros and cons of the thermoneutral temperature as a candidate for optimal temperature are discussed considering the following results of experiments and statements (a) at thermoneutral temperature there is a secondary depression of heat production, (b) there are different special optimum temperatures for different body functions and parameters of performances, (c) role of biological optimum temperature as a favourite candidate for optimal temperature, (d) role of thermoregulatory behaviour in the regulation of optimum body core temperature (e) role of postnatal acclimatisation and epigenetic temperature adaptation in influencing the optimal temperature. It is finally concluded that it is be impossible to estimate a single optimum temperature for animal keeping because of the physiological peculiarities of the physiological system It is recommended to keep all animals and poultry species under free running conditions in houses containing separated compartments with different climatic conditions: the individuals are able to search for conditions that satisfy their individual thermoregulatory demands.