[The assessment of risk factors of development of extra body mass in children of school age].

The global problems of children health include overweight and obesity and associated high risks of disability, premature death and complications of mental health in adult age. Purpose of the study is to identify alimentary and social risk factors of development of extra body mass in children and adolescents 7-17 years old residing in industrial center of the Eastern Siberia. The average age of studied group of children was 10.95 years. The sampling survey and anthropometric examination of children of school-age was carried out with participation of their parents (legal representatives). The results were evaluated by parametric statistical methods. The analysis testifies predominantly fat-based dietary model in children with normal and extra body weight. It is established that diet of children is inadequate in fish, curds, cultured milk food, meat, vegetables, fruits and drinking water. And 51,67-61,90% of children never consumed seafood. The most significant factors associated with extra body mass and obesity in children and adolescents were status of working mother and her specialized secondary education, high body mass index of father, satisfactory family income, high body mass index of mother. The results of study can be useful for correcting and elaborating further strategies of development of healthy diet in institutions of general education.

[The diseases of digestive apparatus: the structure and dynamics at regional level].

The diseases of digestive apparatus significantly contribute into premature mortality of population. In the Republic of Buryatia, the diseases of digestive apparatus occupy third place in the structure of primary morbidity of population (6.7%) and fourth place in the structure of total mortality (6.6%). The purpose of the study is to establish characteristics of structure and dynamics of morbidity and mortality of population because of diseases of digestive apparatus in the Republic of Buryatia in 2009-2018. The analysis was based on data from state statistical reporting forms and official reports of the Territorial Authority of the Federal State Statistics Service in Republic of Buryatia for 2009-2018, reporting and accounting forms of medical organizations. The study was carried out using statistical, analytical methods, as well as elements of comparative analysis. The analysis testifies increasing of indicator of primary morbidity of diseases of digestive apparatus from 4051.0 to 4226.1 per 100 thousand of population and of mortality of diseases of digestive apparatus in the Republic of Buryatia from 60.6 to 62.5 per 100 thousand of population. The main causes of increasing of morbidity and mortality from diseases of digestive apparatus in the Republic of Buryatia are liver diseases, in particular liver fibrosis and cirrhosis because of alcoholization of population, undue diagnostics and treatment of liver pathology in the group "older than able-bodied age".

[Risk assessment for public health associated with nitrate content in crop products].

The increasing need of the population for crop products (СP) makes continuous monitoring of nitrate content an increasingly urgent task. The accumulation of multidirectional data on the effect of nitrates on the state of the body requires further studies to assess the alimentary risk caused by their admission to the population of various regions. The aim of the work was to study the levels of nitrate contamination of CP and assess the associated risk to the health of children and adults in the Baikal Region. Material and methods. The characteristics of СP contamination with nitrates were given according to the results of socio-hygienic monitoring for 2015-2019. The exposure to nitrates was estimated according to the data of their chronic daily intake with RP. Reference exposure levels were used to calculate hazard quotients for different age groups of the population. Results. The average number of annual studies in the Republic of Buryatia was 1000.6 [95% confidence interval (CI) 887.4-1113.8], the proportion of СP with nitrate content in concentrations above the permissible level was observed on average with a frequency of 4.51% (95% CI 4.11-4.91), which was 3.6 fold higher than the Russian average for 2019 - 1.26%. The alimentary effect of nitrates on the adult population of the Republic of Buryatia, due to admission from СP, was estimated as permissible at the level of the average centile trend, and as unfavorable at the level of the 90th centile. In children, nitrate exposure lead to an unacceptable risk at the level of the average centile tendency of the content of the contaminant in СP, which exceeded 1.0. A comparative analysis of СP safety indicators revealed the priority of nitrate pollution in a number of areas of the Republic of Buryatia. The high levels of СP nitrate contamination are primarily caused by the entrance of local products to the consumer market of the Republic of Buryatia. Conclusion. Taken together, the current situation poses a certain health risk and necessitates further in-depth study of the causes and factors of nitrate contamination. To reduce health risk assessment uncertainties, it is necessary to update data on СP consumption levels among different population groups, including preschool and infant children.

[The analysis of morbidity and mortality of population because of diseases of blood circulation system].

The article presents results of comparative analysis of morbidity and mortality of diseases of circulatory system in the Republic of Buryatia in 2003-2018. The population mortality depends on identification of risk factors for cardiovascular diseases, diseases of circulatory system and subsequent coverage of population with medical care, including dispensary monitoring. The analysis was based on data from State statistical reporting forms and official data of the Territorial Board of the Federal State Statistics Service in the Republic of Buryatia, including the form № 12 "The information on number of diseases registered in patients residing in area of medical organization servicing activity"; the form № 025-12/s "The Out-Patient Registration Card"; the form № 25-2/y "The Statistical Coupon for Final (updated) Diagnosis Registration". The study was carried out using statistical, analytical and comparative analysis methods. Currently, in the Republic of Buryatia, diseases of circular system occupying second place in the structure of total morbidity (15.7%) and primary disability of adult population (28.6%) are among leading cause of total population mortality (41.6%).

[The Regional Characteristics of Preventable Mortality of Population].

The concept of preventable mortality makes it possible to assess health care reserves and to identify priorities of their improvement at the regional level. It was established that in the Republic of Buryatia during 2005-2019, the percentage of the first group by the levels of prevention of causes of death of the old list (Preventable) decreased by 6.1%, mainly due to injuries, poisoning and other consequences of external factors. The percentage of the second and third groups increased by 4.4% and 1.7%, respectively. The cause of increasing of preventable mortality are malignant neoplasms and diseases of respiratory system. The increase of mortality from malignant neoplasms made from11.4% i.e. from 166.3 (2005) up to 185.3 (2019) per 100 thousand of population caused by increasing of mortality of malignant neoplasms included in the first group (malignant neoplasms of lip, mouth, pharynx, esophagus, liver, intrahepatic bile ducts, larynx, trachea, bronchi, lungs, urinary bladder). The increasing of mortality from malignant neoplasms in the second group occurred due to malignant neoplasms of skin, including melanoma, breast, cervix, uterus. In this case, the lateness of seeking medical care, which is characteristic of a large part of population is to be considered. The dynamics of proportion of respiratory diseases in the structure of the third group was characterized by wave-like curve, with minimum in 2008 (45.3%), and maximum in 2014 (65.1%). At the same time, overall mortality of respiratory diseases decreased from 84.9 to 54.6 per 100 thousand of population. Taking into account the results of the study, it is appropriate to update existing regional preventive programs with emphasis on improving diagnostic of malignant neoplasms and appropriateness of regular preventive examinations of population of the Republic.

[The social economical losses because of mortality due to alcohol-associated causes].

The evaluation of social economic losses based on the analysis of mortality of alcohol-associated causes in the Republic of Buryatia was carried out. It is established that in the Republic in 1993-2017 the average mortality due to alcohol-associated causes made up to 3.52% of total population mortality. This indicator is significantly higher among died individuals of able-bodied age, reaching 6.98±0.11% in this cohort. The economic damage due to direct alcohol-associated causes of death of individuals of able-bodied age made up to 4,123.9 million rubles, including 2038.3 million rubles in male population and 319.3 million rubles in female population, considering employment of analyzed population cohort. The social and economic damage due to population premature mortality in the Republic of Buryatia and directly related to alcohol consumption was calculated on the basis of potential demography principle. In average, the annual social losses made up to 80,248.37 man-years not survived till the end of able-bodied age. In total, the concomitant economic losses for the mentioned above period made up to 4.1 billion rubles. The obtained data testify both high level of alcoholization of population of the Republic of Buryatia and necessity of the activation of activities targeted to primary prevention.

[Features of actual nutrition of the adult population in Republic of Buryatia in modern conditions].

Evaluation of the actual nutrition of the population of individual regions allows the development of targeted practical measures to improve nutrition, the structure of food consumption and appropriate recommendations to ensure optimal development and health status of a person. In order to study the nutrition of the adult population of the Republic of Buryatia, a retrospective analysis of the feeding structure data was conducted according to the data of the territorial department of the Federal State Statistics Service for the Republic of Buryatia, and the results obtained in the course of the questionnaire survey of 426 people (chosen by selective method with observance of representativeness) were analyzed. The data are presented obtained on the results of comparison with physiological needs in energy and nutrients for men and women in the most employable age of 30-39 years, having the third group of labor intensity. The structure of the food indicates its irrationality, which was confirmed by an increase in the consumption of food products with high content of saturated fats and added sugars, a decrease in the consumption of biologically valuable food products with high food density. In the product mix of the adult population of the republic, both among men and women, there was a lack of consumption of products from aquatic bioresources, vegetables, dairy products and eggs. At the same time, the consumption of bakery, flour-grinding products and potatoes in aggregate amounted to 120% of the recommended level. According to the results of the observation, 91.6% of the interviewed did not take into account the distribution of caloric intake by meals, in 50.8% the highest calorie intake was for dinner. Actual nutrition included elements that are risk factors for the development of endocrine pathology, disorders of the hormonal system and other metabolic diseases. There was a high level of energy intake for a number of years, which averaged 2891±43.6 kcal in men, 2407±38.4 in women, due to excess of fat and carbohydrates with a protein content of 82.4-87.3% of the recommended level. As a result, the problem of healthy nutrition, bringing the diet in line with the real physiological needs of a person requires serious systemic decisions in terms of organizing, systematizing and standardizing nutrition.

[Assessment of nutrition of students of educational institutions of the various type].

Among the risk factors that have priority in shaping the health of the population, a leading place is held by a rational nutrition. Presented results indicate to the absence of a stable group eating regularly, with the rational regularity and having all the necessary meals and the recommended food set. In the population of the adult people of the city of Irkutsk there is revealed the role of the nutritional factor in the formation of morbidity rate level of the adult population. It was found that the risk of diseases of the circulatory system accounted of 2.5 (95% CI: 2.1-3.6), for infectious and parasitic diseases - 2.4 (95% CI: 1.7-3.5), for the endocrine system - 2.2 (95% CI: 1.4-3.4), andfor the urinary system - 2.3 (95% CI: 1,7-3,0).

[RISK ASSESSMENT TO HEALTH OF THE POPULATION OF BURIATIIA IN CONNECTION WITH THE CONSUMPTION OF FOODSTUFF].

Evaluation of the risk associated with contamination of food products coming to the population of the Republic of Buryatia, was performed on the basis of data on the content of contaminants in basic food products and results of the questionnaire survey of the adult population. There are considered groups with taking into account gender differences and dietary preferences. Hazard index of chemical impact of non-carcinogenic substances coming from the food, in the surveyed individuals with predominance of lipid-protein diet is on the border of the permissible level (HI = 1,06-1,18). There are most probable effects of negative impact of toxicants with a significant proportion of the diet of imported products: in females--on the endocrine system (HI = 1.27-2.83), central (HI = 1.35) and the autonomic nervous system (HI = 1.29); in males--on the endocrine system (HI = 2.7). Carcinogenic risks are in the second range (more than 1 case per 10,000 people), the main contribution (62.2-78.9%) into the number of additional cases of malignant tumors among the population of the Republic of Buryatia is made by cadmium.

Studies of the synaptic plasticity of field CA3 of the hippocampus during tetanization of the perforant path.

Studies on living slices of hippocampus-entorhinal cortex formation from adult rats were performed to investigate changes in responses in field CA3 to stimulation of mossy fibers in conditions of perforant path tetanization with different parameters. Tetanization of the perforant path at frequencies of 10 and 100 Hz induced depression of responses in CA3 on testing of this same path. Tetanization of the perforant path at a frequency of 10 Hz and an amplitude subthreshold for potentiating mossy fiber synapses in CA3 became threshold if preceded by tetanization of the perforant path at a frequency of 100 Hz. Tetanization of mossy fibers at 10 Hz resulted in potentiation of the input to CA3, while tetanization at 100 Hz induced depression. High-frequency tetanization of the perforant path (100 Hz) delivered in trains following at the frequency of the theta rhythm, led mainly to depression of field CA3 responses to stimulation of mossy fibers.

Post-tetanic changes in background gamma oscillations in interhemisphere interactions.

Experiments conducted on the motor cortex of anesthetized rats were performed to study the effects of high-frequency microstimulation of one of the hemispheres on oscillation parameters in neuronal networks containing callosal cells. Before tetanization, there were three modes in the distribution of gamma oscillation periods, corresponding to frequencies of 40-60, 70-100, and 100-200 Hz. In cells active in pre-tetanization background conditions, the three modes were retained after tetanization; there was a relative increase in the number of oscillatory interactions in that part of the gamma range (40-60 Hz) which dominated before tetanization. The distribution of oscillation periods in neurons which became active in background conditions after tetanization contained the same three modes. Tetanization resulted in a relative decrease in the number of oscillatory interactions and the number of neuron pairs in which additional synchronization occurred, along with a reduction in the extent of oscillations, which is evidence of reduced synchronization. Existing modeling data taken together with the present results led to the suggestion that these post-tetanization changes were based on a modification of the efficiency of excitatory and inhibitory inputs to neurons in both hemispheres.

Background gamma-oscillations in neuronal networks with interhemisphere connections.

Results obtained in studies of the high-frequency components of EEG recordings and in modeling, determining the conditions for the appearance of gamma oscillations in interneuronal interactions, were compared with features of the background gamma oscillations recorded in the activity of interacting neurons located in symmetrical loci of the right and left hemisphere motor areas in anesthetized rats. Similarities in high frequencies extracted from EEG recordings and in the most commonly observed gamma oscillation frequencies suggested that these oscillations may represent one of the mechanisms underlying the high-frequency EEG component. Published modeling data indicating that the formation of these oscillations involves reciprocal inhibitory connections, along with our own data that interhemisphere oscillations are seen 1.5 times more commonly than ipsilateral oscillations, suggested that transcallosal inhibition is more effective than inhibition between neighboring cells. Simultaneously extracted background oscillations in the interacting activity of callosal cells and neighboring cells could be different, as could those characterizing the activity of individual neurons. It is suggested that these differences underlie the functional heterogeneity of local cortical neuronal networks and explain the fact that these networks contain various types of inhibitory neurons.

The properties and possible mechanisms of interhemisphere synchronization in the motor cortex of the rat.

Cross-correlation analysis was used to observe interhemisphere synchronization of motor cortex neuron activity in anesthetized rats, which was seen on cross-correlograms as peaks located symmetrically relative to the coordinate origin. Peaks included "narrow" peaks (less than 20 msec) and "intermediate" peaks (30-80 msec). The results showed that the "common" source synchronizing the discharges of pairs of neurons located in different hemispheres of the brain might be a neuron (or group of neurons) located in one of the hemispheres and playing this role when there were reciprocal excitatory connections between it and each neuron in a pair. Comparison of the widths of symmetrical peaks with latent periods corresponding to transcallosal connections suggested that mono- and polysynaptic connections underlie the formation of "narrow" and "intermediate" peaks respectively.

The effects of high-frequency microstimulation of the cortex on interhemisphere synchronization in the rat motor cortex.

Studies were carried out on long-term changes in the synchronization of neuronal activity in networks including callosal cells of the opposite hemispheres evoked by high-frequency microstimulation in the motor cortex of anesthetized rats. The level of synchronization was assessed in terms of the amplitude and width of peaks located symmetrically on cross-correlograms relative to the coordinate origin. Tetanization predominantly decreased synchronization in a group of initially background-active neurons, while there was a significant number of synchronously firing neurons in a group of cells which became activated. "Super-narrow" peaks appeared in interhemisphere interactions. There was a correlation between the type of modification of "narrow" (<20 msec) and "intermediate" (30-80 msec) peaks and changes in the efficiencies of mono- and polysynaptic connections.

Post-tetanic modification of the efficiency of excitatory transmission in neural networks including interhemispheric connections.

This is the first report of modifiable reciprocal transcallosal monosynaptic excitatory connections, detected in in vivo experiments in the rat motor cortex by recording of multineuron activity and cross-correlation analysis. High-frequency microstimulation of a small group of cortical neurons in one hemisphere was shown to alter the efficiency of transcallosal excitatory connections, and also altered the efficiency of ipsilateral connections in both hemispheres. Post-tetanic changes consisted of long-term potentiation and depression. Neurons producing spike trains were found to have better conditions (compared with other neurons) for long-term potentiation of inputs converging on them. Synapses formed by axon collaterals of a given callosal cell on several neurons could simultaneously induce both long-term potentiation and long-term depression, while a given callosal neuron could simultaneously show long-term potentiation in some synapses and long-term depression in others. After microstimulation there were increases in the number of background-active callosal neurons, along with increases in the number and efficiency of transcallosal connections, while the number and efficiency of ipsilateral connections decreased. These data lead to the conclusion that ipsilateral inhibition is more effective than transcallosal inhibition. Microstimulation modified the pattern of initially existing connections between the many elements of ensembles including callosal cells in both hemispheres.

[The baseline gamma oscillations in neural networks with interhemispheric connections]. / Fonovye gamma-ostsilliatsii v neironnykh setiakh s mezhpolusharnymi sviaziami.

The evidence obtained from the studies of EEG high-frequency components and computer simulation which determined the necessary conditions for occurrence of oscillations were compared with some features of spontaneous gamma oscillations, which had been revealed by us in interconnections of neurons located in symmetrical loci of both hemispheres of motor cortex of anaesthetized rats. Based on the similarity of the most expressed high-frequency EEG components and dominant frequencies of gamma oscillations, we proposed that gamma oscillations could underlie the appearance of the high-frequency EEG components. Taking into account the obtained by us results that interhemispheric oscillations occurred 1.5 times more frequently than ipsilateral and the evidence from computer simulation experiments that reciprocal inhibition underlies oscillations in neural networks, we suggested that transcallosal inhibition was more effective than inhibition between the neighbouring cells. Parameters of simultaneously revealed spontaneous oscillations caused by interhemispheric and ipsilateral interactions and in individual cell activity could be different. It was assumed that functional variability of local neocortical networks and participation of different inhibitory neurons underlie distinctions in oscillation parameters.

[Posttetanic changes in the background gamma oscillations in interhemispheric interactions]. / Postteanicheskie izmeneniia fonovykh gamma-ostsilliatsii v mezhpolusharnykh vazimodeistviiakh.

The influence of high-frequency microstimulation (HFMS) of one of the hemispheres on the parameters of spontaneous gamma-oscillations in the neural network containing callosal cells of the motor cortex of both hemispheres. There were three modes in the background oscillation periods distribution, which corresponded to the frequencies 40-60, 70-100, and 100-200 Hz. These oscillation frequencies were also revealed after the HFMS in neural interactions of the cells, which were active before the HFMS; the frequency 40-60 Hz, which dominated before the HFMS, became even more pronounced. The same three groups of oscillation frequencies were found in the activity of cells which became active after the HFMS. The expression of oscillations, the number of oscillatory interactions, as well as the number of neuronal pairs with additional synchronization decreased after the HFMS, which suggests a decrease in synchronization. Taking into account the results of simulation experiments that the frequency of gamma-oscillations is determined by the strength of inhibitory and excitatory input, we suggest that the long-term posttetanic modifications in the efficacy of synaptic inputs of the neurons of both hemispheres underlie the observed posttetanic changes.

[Post-tetanic modification of the efficacy of excitatory transmission in neuronal networks with interhemispheric connections]. / Posttetanicheskaia modifikatsiia éffektivnosti vozbuditel'noi peredachi v neironnykh setiakh s mezhpolusharnymi sviaziami.

The modifiable reciprocal transcallosal monosynaptic excitatory connections were for the first time detected in vivo experiments in rat motor cortex using multiunit recording and crosscorrelation analysis, It was shown that high-frequency microstimulation (MCS) of a small group of cortical cells of one hemisphere produces long-term changes in the efficacy of transcallosal excitatory connections, and also ipsilateral connections in both hemispheres. The posttetanic changes appear as long-term potentiation (LTP) and long-term depression (LTD). The bursting neurons were found to have more favorable conditions for the induction of LTP of most converging inputs (in contrast to cells with other discharge patterns). Both LTP and LTD could be simultaneously induced in synapses formed by axon collaterals of a callosal cell on several neurons. LTP and LTD could be simultaneously obtained at diverse synapses of the same cell. The number of spontaneously active callosal neurons as well as the number and efficacy of transcallosal connections increased after the MCS, whereas the number and efficacy of ipsilateral connections decreased. Basing on these data we assume that the ipsilateral inhibition is more effective than the transcallosal inhibition. MCS results in the modification of the pattern of initially existing connections between numerous neurons of an ensemble including cells of both hemispheres.

[Study of synaptic plasticity of hippocampal CA3 area as a result of tetanization of perforant path]. / Issledovanie sinapticheskoi plastichnosti oblasti CA3 gippokampa pri tetanizatsii perforantnogo puti.

Evoked responses in CA3 area to the mossy fibers stimulation were studied after low and high frequency tetanizations of the perforant path. Stimulations of perforant path with 10 and 100 Hz frequencies inducted depression testing through the same path. Subthreshold for potentiation of the mossy fibers inputs to the CA3 tetanization of the perforant path with 10 Hz frequency transformed to threshold one after previous tetanization of the perforant path with 100 Hz frequency. Tetanization of the mossy inputs to the CA3 with 10 Hz frequency leaded to potentiation whereas tetanization with frequency 100 Hz depressed the same inputs. High frequency tetanizations (100 Hz) of the perforant path with theta-rithm frequency stimulation basically depressed of the CA3 evoked responces to the mossy fiber stimulation.