Vol 162, No 1 (2016)

Activity of NMDA receptors is a prerequisite for numerous but not all forms of neuronal plasticity and learning. The present study examined the role of NMDA receptors in standard, weak, and repeated passive avoidance training in young chicks. Injection of MK-801, an antagonist of NMDA receptor, prior to strong training episode impaired subsequent memory recall. Moreover, repeated training did not restore the lost memory. In the double weak training protocol, the impairing effect of MK-801 was observed only when it was injected prior to the second but not to the first training episode. These results suggest that activation of NMDA receptors is not a necessary stage for memory acquisition in the weak training task. In contrast, the mechanisms of strong training depending on activation of NMDA receptors can be probably involved into the second training episode performed against the background of existing NMDA receptor-independent memory about the first training episode.

The study examined the effect of α₁-adrenoceptor stimulation with methoxamine on chronotropic function of isolated heart perfused ex vivo according to Langendorff and cardiac chronotropy in vivo. Stimulation of α₁-adrenoceptors in isolated heart induced gradually developing bradycardia, which progressed during several minutes. Similar stimulation in vivo produced a short-term bradycardia probably terminated by the compensatory influences in the whole organism. Comparison of the data obtained in both experimental paradigms during α1-adrenoceptor stimulation revealed unidirectional changes in cardiac chronotropy characterized with time-related peculiarities.

Tension in contracting muscle fiber under conditions of ramp stretching rapidly increases, but after reaching a critical stretch P_c sharply decreases. To find out the cause of these changes in muscle fiber tension, we stopped stretching before and after reaching P_c and left the fiber stretched for 50 msec. After rapid tension drop, the transient tension rise not accompanied by fiber stiffness increase was observed only in fibers heated to 25°C and stretched to P_c. Under other experimental conditions, this growth was absent. We suppose that stretch of the fiber to P_c induces transition of stereo-specifically attached myosin heads to pre-power stroke state and when the stretching is stopped, they make their step on actin and generate force. When the tension reaches P_c, all stereospecifically attached myosin heads turn out to be non-stereospecifically, or weakly attached to actin, and are unable to make the force-generating step.

Selective agonists of μ₁- and μ₂-opioid receptors endomorphin-2 and endomorphin-1 injected intravenously in a dose of 4500 nmol/kg in 5 min before coronary blood flow resumption had no effect on cardiac reperfusion damage. Consequently, μ₁- and μ₂-opioid receptors are not involved in the regulation of heart tolerance to reperfusion injury. Nonselective opioid receptor agonist β-endorphin (100 nmol/kg) also did not affect heart tolerance to the pathogenic effect of reperfusion.

We revealed some features of the left ventricular functional geometry in patients with myocardial diseases with different degrees of left ventricular systolic dysfunction. A negative correlation was found between the spatio-temporal heterogeneity of the kinetics of the left ventricular wall during systole and ejection fraction in normal heart and in systolic dysfunction. The differences in the quantitative characteristics of the functional geometry between patients and normal subjects and between different groups of patients depended on the severityof left-ventricular systolic dysfunction. In particular, spatial heterogeneity index that characterizes heterogeneity of systolic movement of the wall segments and end-systolic Fourier shape-power index characterizing complexity of the left ventricle shape during systole differed significantly in the examined groups of patients and have the greatest diagnostic power.

In a 3-month study, 30 obese patients were assigned to lifestyle modification therapy, which is the major component of all modern strategies correcting the metabolic syndrome. The 3-month course of non-pharmacological therapy significantly diminished the major index evaluating the state of these patients, i.e., the risk of cardiovascular disasters. This therapy positively affected all the states associated with metabolic syndrome: arterial BP attained the targets in 53% patients together with normalization of their nocturnal arterial BP dipping status; the lipid panel and carbohydrate metabolic indices normalized in 46 and 44% patients, respectively; hepatic steatosis moderated in 56% patients; and the disturbances in hemostasis were annihilated in 67% patients.

We studied the differences in twitch force of subendocardial and subepicardial cardiomyocytes isolated from mouse left ventricular wall at different preloads using an original single cell stretch method recently developed by us. Then, we used our mathematical models of subendocardial and subepicardial cells to predict underlying cellular mechanisms. Transmural differences in the amplitudes of active tension of subendocardial and subepicardial cardiomyocytes were revealed that could be related to the differences in cooperative end-to-end interaction between the neighboring regulatory units of the thin filament.

Different sensitivity of guinea pigs and rats to Mycobacterium tuberculosis and membranotropic mutagenic xenobiotics is associated with differences in the metabolism of amino acid precursors of phospholipids. In turn, specific features of phospholipid metabolism are determined by differences in the level of sulfur-containing regulatory metabolites (methionine, taurine, and glutathione) in tissues. Taurine and methionine increase organism’s resistance to Mycobacterium tuberculosis (typical of rats), glutathione and its constituent amino acids improve resistance to the mutagenic effects of xenobiotics (typical of guinea pigs). These metabolites can be used for strengthening of natural resistance to tuberculosis and mutagenic and carcinogenic xenobiotics.

Colonization of fluorinated surfaces produced by ion-plasma technology by Staphylococcus aureus was studied by scanning electron microscopy and surface energy analysis. It was shown that the intensity of colonization was determined by the surface relief and fluorine content. Formation of nanostructured surfaces accompanied by a sharp decrease in the surface energy prevented adhesion of Staphylococcus aureus cells to the fluorine-containing surface.

Associations between schizotypal traits and genes coding for inflammation markers (Creactive protein and TNF-α) were studied in 222 healthy men who completed the Schizotypal Personality Questionnaire (SPQ-74). CRP -717A>G and TNFα -308 G>A polymorphisms were genotyped. Carriers of low-active allele G of the CRP gene differed from subjects with genotype AA by a trend toward more manifest schizotypal traits in general and scores on the Interpersonal factor, which corresponds to negative syndrome in schizophrenia, and Constricted affect and Odd behavior scales. These results could be interpreted in favor of the hypothesis on a compensatory increase of CRP concentrations in subjects with abnormalities of CNS development that predispose to schizophrenia.

The effects of Fructus Sorbi aucupariae extract, originally saturated with anthocyans, on the development of Lewis lung carcinoma and B-16 melanoma in C57Bl/6 mice and the efficiency of cyclophosphamide treatment were studied. Antitumor activity of the extract and potentiation of the antimetastatic activity of the cytostatic were demonstrated. Studies on melanoma B-16 model revealed an increase in the counts of stromal progenitor cells in the tumor node and their accelerated maturation after treatment with the extract. No effects towards the tumor stem and committed cells were detected.

We use a mathematical model of one-dimensional blood flow in a network of blood vessels for in silico evaluation of hemodynamic significance of stenoses in multivessel coronary disease. Two cases were addressed: two stenosed vessels with different diameters and with the same degree of occlusion and two consecutive stenoses in the same vessel. We show that two criteria for the evaluation of hemodynamic significance based on the degree of stenosis and based on fractional flow reserve can give contradictory indications for surgical intervention. We also show that fractional flow reserve computation originally proposed for a single stenosis should be modified in the case of multivessel stenotic disease.

Activities of superoxide dismutase and catalase characterizing antioxidant status of the nervous tissue and its resistance to free radical oxidation were measured in the brainstem of rats with hydroxybutyrate-induced pathological periodic breathing. Hydroxybutyrate modified the pro- and antioxidant status in the brainstem respiratory center. It markedly inhibited catalase activity; in rats without the signs of periodic breathing, hydroxybutyrate up-regulated superoxide dismutase activity and to a lesser extent increased the resistance of the membrane structures in the medulla oblongata to induction of free radical oxidation. In rats with periodic breathing pattern, hydroxybutyrate induced more pronounced increase in the sensitivity of membrane structures in the medulla oblongata to induction of free radical oxidation.

Tropomyosin plays an important role in the regulation of actin—myosin interaction in striated muscles. Mutations in the tropomyosin gene disrupt actin—myosin interaction and lead to myopathies and cardiomyopathies. Tropomyosin with mutations in the α-chain is expressed in both the myocardium and skeletal muscles. We studied the effect of mutations in the α-chain of tropomyosin related to hypertrophic (D175N and E180G) and dilated cardiomyopathies (E40K and E54K) on calcium regulation of the actin–myosin interaction in skeletal muscles. We analyzed the calcium-dependent sliding velocity of reconstructed thin filaments containing F-actin, troponin, and tropomyosin over myosin surface in an in vitro motility assay. Mutations D175N and E180G in tropomyosin increased the sliding velocity and its calcium sensitivity, while mutation E40K reduced both these parameters. E54K mutation increased the sliding velocity of thin filaments, but did not affect its calcium sensitivity.

The leading role in the regulation of erythropoietic activity of adherent bone marrow cells under conditions of post-hemorrhagic anemia is played by classical MAP kinase pathway (ERK pathway). Erythropoietin is not the decisive factor in the formation of erythropoietic activity of adherent cells. PI3K, MAPK/ERK 1/2, and p38-signaling proteins are not the main regulators of local production of erythropoietin after 30% loss of circulating blood volume.

In vitro production of immunoregulatory cytokines (IFN-α, IL-31, TNF-β, IL-17A, IL-7, IL-1RA, IL-1α, IL-10, IL-15, IL-21, IL-22, IL-23, IL-27, and IL-9) by dendritic cell cultures was compared in ski athletes and healthy donors. Effect of prolonged intense physical exercise on secretory activity of immune cells was investigated. In both groups, secretion of IL-1RA, IL-10, IL-1α by dendritic cells was revealed, but there were significant differences in IL-1RA, IL-1α content (p<0.05) with lower level in the group of athletes. Production of IL-17A and IL-7 by dendritic cells in the group of athletes was not detected. In athletes, several proinflammatory cytokines (IFN-α, IL-31, and TNF-β) were secreted by cells in high concentrations, in contrast to the control group. In both groups, dendritic cells did not secrete IL-15, IL-21, IL-22, IL-23, IL-27, and IL-9.

A producing strain of an anti-tumor and antiviral enzyme L-lysine-α-oxidase from Trichoderma was cultured using a technological device of G. K. Skryabin Institute of Biochemistry and Physiology of Microorganisms, Russian Academy of Sciences (Pushchino). L-lysine-α-oxidase activity in the obtained metabolite concentrate was 5.4 U/ml. We studied the effects of the concentrate of active L-lysine-α-oxidase producer on the highly infectious Tobacco ringspot virus and revealed anti-viral activity of it when enzyme concentration was at least 1.0 U/ml.

Predisposition to antisocial behavior can be related to the presence of certain polymorphic variants of genes encoding dopaminergic system proteins. We studied the frequencies of allele variants and genotypes of variable number tandem repeat polymorphism in 3’ untranslated region (3’ VTNR) of the dopaminergic transporter SLC6A3 gene in Caucasian men committed socially dangerous violent and non-violent crimes. Alleles with 9 and 10 repeats were most frequent in both the control group and group of men predisposed to antisocial behavior. At the same time, the 10/10 genotype was more frequently observed in the group of men prone to antisocial non-violent behavior. Hence, the presence of certain variants of 3’ VTNR polymorphism of SLC6A3 gene in men is associated with predisposition to certain forms of antisocial behavior.

We studied the possibility of using membrane fabricated from type 1 collagen isolated from cattle tissues (group 1) or porcine tissues (group 2) for replacement of the resected bladder wall defect in rabbits in order to retain functional volume of the organ. Satisfactory take of both types of collagen membranes with formation of competent anastomosis was observed. Histological studies revealed inflammatory process in the bladder wall at the site of contact with the implanted membrane (more pronounced in case of membranes from cattle tissues) that decreased by day 21 of the experiment. Bladder tissue ingrowth into the implant from was observed starting from day 14. The bladder capacity decreased in 7 days after surgery in both groups, presumably because of increasing tone of the organ wall resulting from surgical trauma and inflammation. In group 2, the bladder volume increased by day 14 after surgery and returned to normal by day 21, whereas in group 1 it remained below the control despite a trend to increase. These findings confirm good prospects of using collagen-1 membranes for plastic repair of the urinary bladder, the membranes from porcine collagen being more preferable.

Studies with the use of highly sensitive enzymatic sensor have shown the presence of various forms of nitrosyl iron complexes, including those undetectable by other methods, in living tissues. All these complexes are long-living compounds and constitute the major part of nitroso compounds in the blood, muscles, liquor, and amniotic fluid.

The cells isolated from biopsy specimen of a patient with alcoholic liver cirrhosis and cultured under standard conditions for obtaining stromal cell culture clearly diverged during early passages into two morphologically and phenotypically different subtypes: epithelial and mesenchymal. Mesenchymal cells expressed CD90 and CD44 and epithelial cells expressed CD166, CD227, and hepatocyte growth factor receptor Met. Starting from passage 6, the culture underwent spontaneous morphological changes and by passages 8-10 contained only epithelium-like cells. CD90 and CD44 expression disappeared, CD166 and CD227 expression remained unchanged, and Met expression increased. A small fraction of cells expressed GATA-4, HNF3β, HNF1α, and HNF4α. After addition of inducers of hepatogeneic differentiation, the cells started producing albumin.

A series of experiments on co-culturing of Mel IL melanoma cells and mesenhymal stem cells showed that these cells do not influence proliferation of each other, but we observed weaker adhesion of stromal stem cells to plastic in cocultures where with melanoma cells were grown on mesenhymal stem cells feeder. Cell proliferation was also considerably influenced by experimental conditions, which should be taken into account for correct interpretation of obtained results. The principles of experiments on co-culturing of cancer and stromal cells are formulated that take into account the most important factors influencing cell behavior and minimize the probability of artifact results. It was concluded that co-culturing conditions cells significantly affect the experimental results and can be the source of conflicting conclusions on mutual influence of stromal and cancer cells in vitro.

Platelet lysate prepared from donor platelet concentrate and pooled according to a developed technique stimulates migration of multipotent mesenchymal stromal cells of the human adipose tissue and promotes healing of the monolayer defect in cultures of human fibroblasts and multipotent mesenchymal stromal cells in vitro in concentrations close those of fetal calf serum (5-10%). Lysate of platelets from platelet-rich rat blood plasma stimulated healing of the skin defect by promoting epithelialization and granulation tissue formation. The regenerative properties of platelet lysate in vivo increased with increasing its concentration.

We studied the possibility of in vivo tracing of multipotent mesenchymal stromal cells labeled with a radiophermaceutic preparation based on metastable isotope Technetium-99m and injected to rats with modeled traumatic brain injury. Accumulation of labeled cells occurred primarily in the liver and lungs. The cells distribution in internal organs greatly varied depending on the administration route. Cell injection into the carotid artery led to their significant accumulation in the damaged brain hemisphere, while intravenous injection was followed by diffuse cell distribution in all brain structures. Scintigraphy data were confirmed by magnetic resonance imaging and histological staining of cells. Visualization of stem cells labeled with Technetium-99m-based preparation by scintigraphy is an objective and highly informative method allowing real-time in vivo cell tracing in the body.

We developed a cytochrome P450 substrate—inhibitor panel for preclinical in vitro evaluation of drugs in a 3D histotypical microfluidic cell model of human liver (liver-on-a-chip technology). The concentrations of substrates and inhibitors were optimized to ensure reliable detection of the principal metabolites by HPLC—mass-spectroscopy. The selected specific substrate—inhibitor pairs, namely bupropion/2-phenyl-2-(1-piperidinyl)propane) for evaluation of CYP2B6B activity, tolbutamide/sulfaphenazole for CYP2C9, omeprazole/(+)-N-benzylnirvanol for CYP2C19, and testosterone/ketoconazole for CYP3A4, enable reliable evaluation of the drug metabolism pathway. In contrast to animal models characterized by species-specific expression profile and activity of cytochrome P450 isoforms, our in vitro model reflects the metabolism of human hepatocytes in vivo.