Том 44, № 1 (2018)

The electrophysiological correlates of major depression disorder with anxious distress in patients of different age groups have been investigated. The spectral characteristics of 19-channel background EEG were analyzed and the power spectra recorded with the eyes closed vs. eyes open in 64 patients with anxiety–depressive disorder and in 194 healthy subjects were compared. The subjects were divided into the two age groups: 18–39 and 40–76 years old. The spectral parameters were calculated for 5 main EEG frequency bands: θ (4–8 Hz), α (8–12 Hz), β₁ (12–20 Hz), β₂ (20–30 Hz), and γ (30–40 Hz). The most statistically significant differences between the groups were found in the α, β, and γ bands. Lower values of spectral power of the α rhythm in occipital areas and the higher values of spectral power of the β and γ rhythms in the frontocentral region were recorded in the group of 18-to-39-year-old patients with the eyes closed. Higher values of spectral power of the β rhythm in the fronto-central region and in the left temporal lobe were recorded in the group of 40-to-76-year-old patients with both the eyes closed and the eyes open. The higher β-activity in the fronto-central regions in both groups of patients may be caused by increased excitability of the cerebral cortex and decreased activity of inhibitory processes. Increased activation of the left temporal lobe in older subjects is probably associated with the severity of anxiety symptoms and may be a distinctive marker of mixed anxiety and depressive disorder. The lower values of α-power revealed only in the group of younger subjects are probably associated with age-related reorganization of EEG in older subjects.

Cognitive potentials measured in players during computer games were used as a tool to assess the number of possible cognitive requests (NPCR) between two mouse clicks. The data obtained in recording cognitive evoked potentials (EP) with pressing a button allowed us to count the frequency of requests towards conscious cognitive processes in the working memory, which was associated with the number of operations of comparison (matching), decision-making, and triggering an action.

A new method was proposed for processing a nonstationary heart rate by using frequency-modulated signals rather than amplitude-modulated signals equally spaced over several points of time as in the conventional method. A frequency-modulated signal is a set of identical Gaussian peaks that coincide with the true time points of heart beats. A continuous wavelet transform was used to quantitatively describe the heart rhythm signal. A test with controlled breathing was performed as an example and included three consecutive stages: rest, rhythmic breathing at a specified frequency, and exhalation. Tachograms recorded during the breath test was found to be a nonstationary signal with the alternation of peaks of different spectral ranges. A system of quantitative parameters was developed to describe the dynamics of changes in the spectral properties of the tachogram in transitional areas. A static clustering by the effect of the respiratory test and a dynamic clustering in order to identify the time points when the autonomic nervous system is stressed were performed for all subjects. The article discusses the prospects of using the method as a means to analyze the transient effects in various functional tests and as biofeedback that would help to change the heart rhythm.

The physiological mechanisms that determined the maintenance of human physical performance in the absence of gravity are poorly understood. The article presents the results of analysis of locomotor training characteristics of 18 cosmonauts who participated in long-term spaceflights at the International Space Station (ISS) with the duration from 175 to 201 days. The level of cosmonauts' physical performance during spaceflight was determined by the results of a locomotor test with a stepwise increasing load. The vertical components of ground reaction forces were recorded for different types of locomotion using load cells in the BD-2 treadmill. The results of determination of changes in the level of cosmonauts' physical performance during long-term spaceflight have provided the data on a higher prophylactic efficacy of locomotor training performed with an axial load of over 64% of the body weight compared to those performed with an axial load of less than 61% of the body weight. The higher countermeasure efficacy of locomotor training in the first case may be due to an increase in the intensity of stimulation of the reference input and the strengthening of the response of systems providing autonomic muscle activity.

It is known that long-term space flights lead to dysregulation of the cardiovascular system, and the endothelium is the most important functional element of such dysregulation. In order to find the signs of endothelial dysfunction in cosmonauts who have been in long-term space flights, we collected urine samples from 21 cosmonauts before the flight and on the first and seventh days after landing. The urine samples were investigated by chromatography–mass spectrometry analysis. Proteins were identified using the MaxQuant software and the SwissProt database. The software package Perseus was used for semi-quantitative analysis. The reconstruction of associative molecular networks was performed using the ANDSystem software. We identified 200 different proteins in urine samples of 21 Russian cosmonauts. The ANDSystem software made it possible to determine seven processes related to endothelium functioning. These processes had direct relations to 17 urine proteins, which were functionally associated with the endothelium. At the same time, eight proteins (such as serotransferrin, prostate-specific antigen, fibrinogen gamma chain, UFO tyrosine kinase receptor, aminopeptidase N, vascular cell adhesion molecule 1, osteopontin, and syndecan-4) were significantly changed (p < 0.01) at different points of the recovery period (the first and seventh days). Thus, we performed the first study of the urine protein composition in cosmonauts for the evaluation of signs of endothelial dysfunction after space flight using proteomics methods.

Functional tests with incrementing axial load on the affected limb were performed in patients with humerus, tibia and fibula fractures, or undergoing tibial bone lengthening using the Ilizarov apparatus (n = 75). It was found that oossification was associated with a decrease in the blood flow velocity in the arteries of the bone regenerate. In the humerus, the exercise tolerance was two to three times lower, while the micromotion rate of bone fragments and the blood flow velocity were higher. The micromotion rate and the blood flow velocity decreased by the end of the fixation period, since they were no longer affected by the incrementing load.

In recent years, there has been an increasing interest in myostatin, a hormone that inhibits the growth and differentiation of muscle tissue. This interest is associated with an increase in the amount of data on the spectrum of the myostatin functioning. Myostatin, which has been known since 1997, belongs to the family of transforming growth factor β (TGF-β) and is a paracrine factor of skeletal muscle myocytes. It turned out that myostatin also affects the satellite cells and muscle fibroblasts, and its functions are not only to limit growth, but also to remodel skeletal muscles, which is necessary for muscle adaptation to physical training. Recent studies show that myostatin can play a significant role in musculoskeletal and cardiac cachexias in various pathologies, including cancer. It has been found that myostatin can be produced not only by skeletal muscle cells, but also by adipocytes and cardiomyocytes. It has been shown that, in cardiac pathology, the level of myostatin production increases in cardiac tissue. It is suggested that an increase in the myostatin production in the heart is necessary to prevent myocardial hypertrophy, which develops in some cardiac diseases. In this review, we examined the myostatin functions, as well as aspects of myostatin gene expression, mechanisms of its biosynthesis, its effect on various intracellular targets and transcription factors, and the regulation of its production. The importance of myostatin functions, as well as its involvement in pathological processes, allows us to consider this hormone as a promising target in therapeutic studies.

Seven male volunteers aged 22–27 years took part in the laboratory experiment for the determination of body response to acute normobaric hypoxia where they inhaled an oxygen–nitrogen gas mixture (9% of О₂) for 25 min. At least 100 cardiac cycles at each of six experimental time points have been recorded by using an electrocardiogram (ECG) recording technique in standard lead II. Mean heart rate (±SD) before hypoxia was 64 ± 2 bpm; the duration of the PP interval was 0.94 ± 0.07 s, that of the PT interval was 0.51 ± 0.02 s, and that of the TP segment was 0.41 ± 0.07 s. Five minutes after hypoxia, it has been found that heart rate (HR) increased by 19%; the duration of the PP and PT intervals and TP segment decreased by 16%, 6%, and 30%, respectively. Twenty minutes after hypoxia, all the parameters reached their initial values. Five and fifteen minutes after hypoxia, HR reached 59 ± 3 bpm; PP interval and TP segment increased by 9% and 14%, respectively, compared to the initial values; PT interval was the same as the initial value at the baseline. The correlation coefficient r_p (PP/PT) was 0.10–0.54; r_p (PP/TP) was 0.94–0.99. The intervals PP and TP were found to be identical.