[Piezopulsometric analysis of autonomic regulation of the cardiovascular system in an elderly person under stress.]

The article describes the results of using the method of arterial piezopulsometry for non-invasive assessment of the functional state and physiological mechanisms of autonomous regulation of the cardiovascular system (CVS) in an elderly person with acute pain associated with unexpected physical trauma. On the first day, such an effect caused a negative stress reaction in the muscle effectors (ME) of the CVS, provoking an abnormal increase and acceleration of the contractility of the left ventricular myocardium. Analysis of the arterial blood pressure (PP) pulse wave graphs showed that the maximum rate of PP growth - VmaxPP, which reflects myocardial contractility, increased from 625±74 before injury to 2 117±173 mm Hg/s after injury, distorting the contour of the normal PP waveform. The reason for this growth could be the rapid cumulative effect of transmitters of the neuroendocrine sympathoadrenal system on adrenergic receptors (AR) of cardiomyocytes (CM). The results of the spectral analysis of the variability of the parameters of the PP waves confirmed this possibility. It was shown that under stress, norepinephrine from activated sympathetic efferents is added to the already increased content of humoral catecholamines in the extracellular environment of the myocardium near the AR of the CM, which is characteristic of the elderly. At the same time, the activity of parasympathetic efferents, releasing acetylcholine, which inhibits the contractile reaction of the myocardium and, thereby, performs a restraining cardioprotective function, significantly increases. A personalized approach was used for piezopulsometric study of the mechanisms of autonomous regulation of ME CVS under specific conditions of stress.

Effects of Pinacidil and Calcium on Succinate-Energized Rat Heart Mitochondria in the Presence of Rotenone.

The effect of pinacidil was studied on calcium-loaded rat heart mitochondria (RHM) in the presence of succinate and rotenone. In experiments with pinacidil, the swelling of these mitochondria increased in media with NH4NO3 or K-acetate, but the inner membrane potential (ΔΨmito) and the respiration in 3 or 2,4-dinitrophenol-stimulated states of these organelles decreased due to the opening of the mitochondrial permeability transition pore (MPTP) in their inner membrane. These effects were inhibited by cyclosporin A and ADP. It was concluded that the protective effect of pinacidil in the cardiac muscle under ischemia/reperfusion may be associated with both the stimulation of mitochondrial swelling and a decrease in RHM calcium overload resulted in ΔΨmito fall due to mild uncoupling effect of pinacidil.

[ESTIMATION OF THE EFFECTS OF GEOMAGNETIC AND SOLAR ACTIVITY ON THE HUMAN BRAIN BIOELECTRICAL PROCESSES WITH STRUCTURAL FUNCTION].

We investigate the impacts of sharp variations in solar and geomagnetic activity (GMA) at high latitudes on the human brain bioelectrical activity by means of the empirical structure function of multi-channel EEG. Ten healthy men ages 19 to 37 took part in the study. EEG was recor- ded daily over the 25 days test period that was marked by C- and M-class solar flares and geomagnetic storm levels in the G2-G3 range. The EEG signals were used for the estimate of the mul-tivariate temporal structure function (SF) of the first order in 8-dimensional space. The value of the SF correlation radius is used here as an estimation of a scale of the integral temporal correlation structure of multi-channel EEG, while the value of the SF horizontal asymptote is used as an estimation of the spatial correlation structure of EEG. It is shown that GMA variations make an even greater impact on the SF correlation radius, than on the SF asymptote. We reveal the disturbing and modulating effects of geomagnetic and solar activity on the SF parameters and its power spectrum. Thus, the SF of multi-channel EEG allows us to estimate the effects of heliogeophysical factors on the integrated brain reaction as a unitary system and may be used to investigate the environmental influence on the humans.

[Age-Related Features of EEG Coherence in Children and Adolescents Living in the European North of Russia].

The paper presents data on the formation of spatial synchronization of brain potentials in 91 children aged 7-18 years living in European North of Russia. We estimated coherence values for 19 derivations (pair 171) in five EEG frequency bands (delta, theta, alpha-1, alpha-2 and beta). We described age-related changes, gender differences and topical specific features of the formation of coherence in the left and right hemispheres, and in inter- and intrahemispheric synchronization. We carried out computer assessment of the differences in EEG coherence between three age groups of children in order to determine criteria for identification of children with retarded formation of spatial organization of local EEG processes. Age-related changes in the structure of EEG patterns observed in the study reflect the processes of morphofunctional brain development in children and adolescents at different stages of postnatal ontogenesis under severe conditions of northern climate.

[General Features of the Formation of EEG Wave Structure in Children and Adolescents Living in Northern European Russia].

The article presents the results of the analysis of EEG wave structure formation in children and adolescents aged 7-18 years living under severe conditions of the North. The approaches developed in discrete mathematics (the graph theory, the theory of network flows) were used to assess the time-frequency transformations of EEG patterns. We evaluated conditional probabilities of reciprocal transitions between the components of six frequency bands of E EG (delta, theta, alpha-1, alpha-2, beta-1, beta-2). We described age- and sex-related features as well as regional specificities of the EEG wave structure. We defined the age periods of reorganization of diffuse EEG activities into the main EEG rhythms; the role of distinct rhythms in the maintenance of the EEG wave structure and its dynamic rearrangements was also discussed. The age-related changes of the structure of EEG patterns form some general picture of the morphofunctional development of brain in children and adolescents at different stages of postnatal ontogenesis under severe climate and socio-economic conditions of the North.

[INFLUENCE OF SOCIAL FACTORS ON PERSONAL SOCIAL AND PSYCHOLOGICAL ADAPTATION AND FUNCTIONAL STATE OF THE CNS IN NORTHERN CHILDREN].

The results of the socio-psychological and psycho-physiological study of children and adolescents rural secondary school in a remote area of the Arkhangelsk region were studied. It was found that the poor situation of children in families at social risk leads to a decrease in their school performance, motivation to succeed and, in some cases, to reduce their personal social and psychological adaptation. However, in general, the level of personal social and psychological adaptation in the majority of surveyed students is high enough. As complementary social institutions, the family and the school, in some cases, can compensate for a number of adverse social and psychological factors. Pupils from social risk groups functional state of the central nervous system has been significantly reduced compared with children who are brought up in affluent families. In the North adverse social factors may increase the effects of the harsh climatic conditions and are an important risk factor for children's health.

Longitudinal study of EEG frequency maturation and power changes in children on the Russian North.

The aim of the study was to reveal longitudinal changes in electroencephalogram spectral power and frequency (percentage frequency composition of EEG and alpha peak frequency) patterns in normal children from northern Russia. Fifteen children (9 girls and 6 boys) participated in the study. The resting state (eyes closed) EEGs were recorded yearly (2005-2013) from age 8 to age 16-17 for each child. EEG frequency patterns were estimated as the percentages of waves with a 1 Hz step revealed by measuring the interval durations between points crossing zero (isoline) by a curve. EEG spectral power changes were analyzed for delta (1.5-4 Hz), theta (4-7.5 Hz), alpha-1 (7.5-9.5 Hz), alpha-2 (9.5-12.5 Hz), beta-1 (12.5-18 Hz) and beta-2 (18-30 Hz) bands. According to the frequency composition of the EEG signals fast synchronous, polymorphous synchronous, polymorphous desynchronous and slow synchronous types of children EEG were revealed. These EEG types were relatively stable during adolescence. In these EEG types, the frequency patterns and spectral power dynamics with age had several common and specific features. Slow wave percentage and spectral power in the delta band remarkably decreased with age in all groups. Starting from the theta band the EEG types were characterized by different EEG spectral power changes with age. In fast synchronous EEG type, the theta and alpha-1 EEG power decreased, and the alpha-2 power increased in the occipital and parietal areas. The polymorphous synchronous type was characterized by increased both the alpha-1 and alpha-2 power with regional peculiarities. In the polymorphous desynchronous type spectral power in all bands decreased with age, and in the slow synchronous type, the alpha-1 power massively increased with age. Obtained results suggest predictive strength of the spatial-frequency patterns in EEG for its following maturation through the years.

[Reflection of reserves of the brain energy mechanisms in cerebral blood flow dynamics in human under acute hypoxia].

Results of experimental researches of the cerebral blood flow (CBF) dynamics in human under acute hypoxia have been analyzed in the paper. It was found that changes of CBF under severe acute hypoxia are of nonlinear character and have several phases--the primary growth in the first minutes of hypoxia, relative stabilization and secondary growth. Secondary growth has no relation to changes of the hypoxemia level. It begins earlier under more severe hypoxia and in individuals with less resistance to oxygen deficit. Opposite to this, hypoxic training prolongs the time from the onset of hypoxia till the moment of the CBF secondary growth. The hypothesis was suggested that the CBF secondary growth reflects a phase of certain exhaustion of the brain's neuronal mitochondrial reserve capacity, which is accompanied by accumulation of vasoactive substances--precursors of ATP.

[Age dynamics and seasonal variations of parameters of cerebral circulation in children and adolescents from European north].

Age dynamics and seasonal variations in cerebral blood flow was studied by means of transcranial Doppler in 95 the natives of the Arkhangelsk region school students aged 7 to 18 years. The results of longitudinal (from 2005 to 2014) study of students are presented. The linear blood flow velocity (BFV) showed gradual declining from junior to senior school age, and BFV were in the middle cerebral artery below average, and in the basilar artery--above mid latitude standards. The influence of the seasonal factor is more pronounced in the younger (for boys) and intermediate (for girls) age group and leveled in the older group. The largest seasonal changes were obtained in BFV in carotid arteries, the relative constancy--in BFV in the basilar artery. Estimated by the resistivity index RI circulatory resistance in the younger and intermediate school students groups decreased in the carotid arteries in the spring and summer, and in the posterior cerebral artery territory--in the winter. BFV rate variability identifies groups of children with varying degrees of "sensitivity" to the influence of seasonal factors.

[Psychophysiological and cardiohemodynamic effects of solar, geomagnetic and meteorological factors in man living in Arctic area].

Complex investigation of solar, geophysical and meteorological factors as well as lunar cycle-phases effects on the indices of cardiohemodynamics, emotional state and the CNS functional state was carried out in 12 males 19-38 years old living in the Arctic region (Apatity, 67°57' N, 33°39' E). The observation period was characterized by flares of M1-M2-class as well as geomagnetic storms of G1-G3 class. Adaptive modulatory effect of environmental factors was shown on the autonomic regulatory systems, as well as a strongviolation action of geomagnetic storms and solar chromosphere flares were revealed on the human functional state. Multiple regression method allowed us to obtain the dominant environmental factors by magnitude of their action on functional parameters, and to estimate the combined effect of these factors. The coefficient of determination in the most cases did not exceed 0.5, but in a certain subjects reached 0.7-0.8 on some indicators. Data show the selective nature of the multiple effects of environmental factors on indicators of functional and emotional states at various persons. Each of examined subjects living in the high latitude extreme conditions reacts on permanent climatic-geographic and cosmophysical factors variation, however both a character and magnitude of reactions were dependent on personal susceptibility to isolated and combined actions of these factors.

[Age and gender characteristics of the content of macro- and trace elements in the organisms of the children from the European North].

By means of the nuclear-emission spectral analysis with inductively connected argon plasma were studied the contents of 28 macro- and trace elements (Al, Ag, Li, Ba, Bi, Ca, Cd, Co, Cr, Cu, Fe, Ga, In, K, Mg, Mn, Na, Ni, Mo, P, Zn, Se, Tl, Pb, Sr, S, Si) in the hair of children and teenagers living in the European North of the Russian Federation (Arkhangelsk region). There were revealed both: decrease and increase of some elements' contents. Also were revealed the dynamics of mentioned elements contents in the hair of the same children in different years. Significant individual variability of the macro and trace elements' status of children-northerners and some gender dependence were revealed.

[Effects of acute normobaric hypoxia on free plasma amino acids metabolism in humans].

We demonstrated significant changes in levels of several plasma free amino acids--proline, hydroxyproline, glycine, and phenylalanine--in healthy volunteers in response to severe acute normobaric hypoxia (breathing nitrogen-oxygen mixture with 9% of O2). We assume that demonstrated an increase of free proline, hydroxyproline, and glycine in plasma in the 10th minute of hypoxia was caused by increased collagenolysis due to hypoxic activation of matrix metalloproteinases. Significantly increased levels of free phenylalanine in the 10th and 20th minutes of hypoxia were the consequences of autophagy activation. Our results suggest that acute severe normobaric hypoxia has specific effects on plasma free amino acids in healthy humans.

[Features of seasonal reorganizations of the central mechanisms of regulation in children northerners with different level of social risk].

The paper presents a comparative analysis of frequency, spatial-temporal parameters and three-dimensional localization of EEG sources that characterize changes of cortical-subcortical interactions processes in autumn and spring periods at northern schoolchildren living in satisfactory and disadvantaged (risk group) conditions of the social (family) environment. Seasonal rearrangement of interaction between wave components of main EEG rhythms was revealed. School students present regressive changes in the EEG pattern temporal organization in spring compared to autumn, and this effect was more expressed at adolescents from group of risk. Data EEDS-tomography showed increased activity in the prefrontal, cingular and subcallosal areas of the cortex in the autumn period that could be related to the mechanisms of season depression caused by the significant reduction of the day length in the North. The increased activity of the limbic system structures which is persisted in the spring in adolescents from risk group narrows the range of regulation of adaptive reactions. Unfavorable conditions of the family environment are an additional stress factor to increased load on the regulatory mechanisms that have a negative impact on the emotional-motivation behavior of children and adolescents, thus increasing the risk of the school and of social disadaptation.

[EEG correlates of geno-phenotypical features of the brain development in children of the native and newcomers' population of the Russian North-East].

Traditional and original methods of EEG analysis were used to study the brain electrical activity maturation in 156 children and adolescents from 7 to 17 years old who represented the native (Koryaks and Evenks) and newcomers' populations living in severe climatic and geographic conditions of the Russian North-East. New data revealing age-, sex- and ethnic-related features in quantitative EEG parameters are presented. Markers are obtained that characterize alterations in the structure of interaction between different EEG rhythms. The results demonstrate age-dependent transformation of this structure separated in time for both different cortical areas and different EEG frequency bands. These alterations show time lag from 2 to 3 years in children of native population compared to the newcomers. The revealed differences are assumed to reflect geno-phenotypical features of morpho-functional CNS development in children of the native and newcomers' population that depend on strong adaptation tension for extreme environmental conditions.

[Individual systemic reactions of human organism under acute hypoxia].

Results of physiological and biochemical study including analysis of brain electrical activity dynamics, volumetric and linear parameters of cerebral blood flow, plasma stress hormones levels (adrenaline, noradrenaline, cortisol) and energy metabolism markers (glucose, lactate) at different stages of acute normobaric hypoxia are presented. The correlations are shown between alterations of main cerebral arteries tone and resistivity type vessels, as well as between changes in linear and volumetric cerebral blood flow providing a compensation of the oxygen deficit. Features of EEG dynamics were investigated that characterized CNS regulatory functions and brain electrogenesis disturbance under deep stages of hypoxia. By means of original evaluating methods of interaction structure between different EEG rhythm, EEG markers were obtained that revealed both brain intercentral interaction rearrangements and functional disintegration of systemic brain activity at various stages of acute hypoxia.

[Individual adaptation strategy under extreme environmental conditions in humans].

Starting from the researches of I.M. Sechenov, I.P. Pavlov, A.A. Uchtomskii, the Russian psychophysiological school considers adaptation in connection with the biological and social origin of a man as the integrated, coordinated and self-controlled human organism's reaction to maintain the vital functions in the constantly changing environmental conditions. On the base of well-known systemic-dynamic methodology and scrutinizing the issue of man and environment interaction V.I. Medvedev added to the theory of man's adaptation the activity paradigm that enable to uncover the distinctive features of professional activities in various environment conditions. The theoretical and practical investigations based on the activity methodology gave the opportunity to find out the new principles of interaction between man and environment and on the strategy of adaptive behavior. From this investigations one could see that the main characteristic of interaction "man-environment" is that man represents proactive side, man simulate different adaptation strategies using both genetically-fixed and acquired mechanisms of adaptive behavior.

[Comparisons of cerebral circulation parameters in schoolchildren living in the Far East and European North].

Transcranial Doppler sonography and impedansometry was used to study cerebral circulation in students aged from 7 to 17 living in the North in the "absolute discomfort" area (Magadan region. 62 degrees North, 158 degrees East, n = 167) and "discomfort" area (Arkhangelsk region, 61 degrees North, 41 degrees East, n = 52). New data were obtained about both blood flow parameters in main cerebral arteries, vessels tone and vasomotor reactivity as well as differences between these indices in children from the two northern areas. The results reveal that arterial blood flow velocity (BFV) in cerebral arteries is faster in Koryaks and Evens who are the children of the native population compared to BFV in the children born in the North whose parents represent newcomers. A tendency exists in the form of vascular tone rising in the living in the North students. This tendency is more expressed in children and adolescents from Magadan region which is distinguished from Arkhangelsk region by more severe climate. The indices that characterize individual alterations of cerebral circulation under hypoxic-cold factors as well as population peculiarities related to "polar adaptive type of metabolism" forming are discussed.

[Serum glucose level in acute severe hypoxia in human at rest].

Study of the effects of acute normobaric hypoxia was performed on a group of young healthy males (age 19-23, n = 10). Conditions of acute normobaric hypoxia were modeled by using oxygen-nitrogen mixture containing 8% of oxygen as a breath gas. That level of oxygen corresponds with its partial pressure at 7000 meters above sea level. A number of different analyses were conducted during experiment: levels of glucose, pyruvate, lactate in peripheral venous blood, hemoglobin, pH, hematocrit, partial pressures of 02 and CO2, hemoglobin saturation. It was shown that on 5th minute of hypoxia serum glucose level decreased significantly (p < 0.05). The average decrease was about 0.76 mmol/l in its maximum and lowest individual glucose levels were 4.0 mmol/l or higher. Serum glucose level returned to background values (assessed before the test) at 10th minute of experiment. In our opinion results of the study suggest that syncopal form of height hypoxia may be caused by the reasons other than hypoglycemia.

[Fatty acid of human plasma under the influence of acute strong normobaric hypoxia].

The influence of acute normobaric hypoxia on total pool of human plasma fatty acids was studied in experiment (respiration of hypoxic gas mixture containing 8% of O2, during 25 min). Health status of participants-volunteers and the hypoxia intensity were monitored with a complex of electrophysiological methods: EEC, ECG, measurement of blood pressure, SpO2, evaluation of cardiac output, gas analysis of exhaled air. Using gas chromatography we studied plasma fatty acids total profile (esterificated and non-esterificated) before hypoxia exposure, on 2nd, 5th, 10th, 20th minutes of acute hypoxia and on 5th and 15th minutes of recovery. It was shown that blood saturation value dropped to 52.1 +/- 7.1 % on 25th minute of hypoxia exposure. There were no statistically significant changes in concentrations of total fatty acids, saturated fatty acids, monounsaturated palmitoleic acid, polyunsaturated linoleic and linolenic acids. Significant (p < 0.05) decrease of concentration of oleic and arachidonic acids was displayed that persisted after 15 minutes of recovery period. It is possible to assume that these changes in unsaturated fatty acid concentration were caused by activation of free radical oxidation processes and production of oleic acid derivatives. The performed hypoxic test seemed to be sufficient in order to reveal hypoxia effects on metabolism of individual unsaturated fatty acids.

Age dynamics of evoked brain potentials in involuntary and voluntary attention to a deviant stimulus in schoolchildren from the northern region.

The central mechanisms of involuntary and voluntary regulation of attention in schoolchildren from the northern region were studied using a method based on the P300 wave of evoked brain potentials (the oddball paradigm). Data were compared with results obtained from psychological tests. Differences in the organization of EP were seen in the "passive" and active (counting) perception of deviant stimuli. Three components were identified within the time envelop of the P300 wave, two of which dominated in the frontal and one in the parietal area of the cerebral cortex. The latency of the P300 wave decreased with age in the children, reflecting increased rates of information processing and increases in the volume of operative memory. In passive perception, the statistical relationship characterized by a reduction in P300 latency with age was significant for leads in the central, temporal, parietal, and occipital areas; in active perception, this applied to all areas including the frontal. The most significant changes in P300 parameters were seen in children aged from seven to 12 years, indicating that this period can be regarded as "critical" in the development of learning skills. The roles of the parietal and frontal areas of the cortex in the mechanisms of involuntary and voluntary regulation of attention are discussed, along with the possibility of using the P300 method to identify children with delayed rates of development of voluntary attention in population studies.