Том 42, № 7 (2016)

The results of studying the system of the osteoprotegerin/receptor activator of nuclear factor kappa-B ligand (OPG/RANKL) in 22 Russian cosmonauts after long-term (124–199 days) International Space Station missions are presented. It was found that early readaptation period is associated with changes in the serum concentrations of OPG and RANKL and the production rate of OPG and RANKL in phytohemagglutinin (PHA)-stimulated and non-stimulated mononuclear cells of peripheral blood in vitro. The extent of these changes varied in different subjects. Our data suggest that the OPG/RANKL cytokine system takes part in the processes of bone remodeling in cosmonauts after long-term missions.

The purpose of the study was to analyze morbidity among pilots of different categories of aircraft and to investigate reactivity of the autonomic nervous system (ANS) in pilots of high-maneuver aircrafts who varied in age and flying time. Morbidity of the flying personnel was analyzed based on the data of aviation medical exams. The ANS investigation involved 56 pilots of fighter and assault aircrafts both in inter-flight periods and during duty shifts. Cytochemistry was used to measure glycogen in peripheral blood neutrophils in 77 pilots. It was shown that the pre-stress state in pilots with a flying time of more than 1000 h may transform into chronic stress, provided that flight duties remain heavy. Cytochemical data studies of the concentration of neutrophilic glycogen revealed that the level of this substance was controlled by hormonal components of the sympathetic and parasympathetic divisions of the ANS and indicated the energy potential of peripheral blood leukocytes.

Ultrasound investigations (USI) of the liver, organs and vessels of the gastroduodenal area, as well as blood biochemistry, were performed in two groups of male volunteers on the 4th day of their stay in the conditions of “dry” immersion with and without the application of countermeasures, including the support load imitator (SLI) or high-frequency electromyostimulation. Using ¹³С-methacetin breath test (¹³C-MBT), two other groups were investigated for the effect of immersion on the detoxification activity and metabolic capacity of the liver and the efficacy of SLI. The performed USIs have identified deceleration in the hepatic venous flow and the signs of plethora in the abdominal venous system. Elevated blood levels were detected in pepsinogen, pancreatic amylase, bilirubin total, due to its unconjugated fraction, insulin, and C-peptide. The ¹³C-MBT has shown a slowdown in the rate of ¹³C-methacetin inactivation and a reduction in the hepatic metabolic capacity. The application of countermeasures during the immersion has not affected the ultrasound patterns of the hemodynamic rearrangement in both the liver and the abdomen. High frequency electromyostimulation during the immersion has neutralized the changes in all biochemical indicators except C-peptide, while the application of SLI has led to the restoration of only pepsinogen and amylase to the initial values. In addition, the use of SLI during the immersion counteracted the reduction in the ¹³C-methacetin inactivation rate and did not substantially affect the reduction in the metabolic capacity of the liver.

Six participants of Mars-500 were examined to obtain information about intrapersonal conflicts and life spheres with high emotional tension associated with them by participation in an experiment with prolonged group isolation. The investigation was performed using operational analogy-based neurosemantic psychodiagnostics, with the subconscious regarded as a semantic filter with unstructured semantic information at the input and information structured by the inner world content at the output. The results shed light on the semantic structure of the subjective experience and functioning of protective mechanisms, as well as organizational levels and modality of emotional experience. Before and after a 520-day isolation, all the participants were shown to have intrapersonal conflicts and high emotional tension in the socio-professional sphere, caused by the family/sexual and interpersonal relations and self-assessment, and concerns about life and health. On completion of the isolation, the psychoemotional tension was reduced in interpersonal relations and increased in family/sexual ones.

The purpose of the study was to establish a relationship between trends in sleep alteration and individual adaptation to stress factors in the 520-day isolation study. Psychological evaluations using a battery of motivation tests, Sobchik’s modification of the Luscher personality test, and Mirror coordinograph made it possible to differentiate groups responding to the stress according to the pattern “control” (G-1) or “search” (G-2) manifested in individual styles of behavior and operator’s activity. The two groups exhibited different dynamics of the night sleep structure. Difficulties with falling asleep in G-1 arose on the eve of “landing onto Mars” and end of the experiment, whereas in G-2 they were evident prior to the end only. In addition, the micro- and segmental sleep structures were more stable in G-1, suggesting the integrity of somnogenic mechanisms despite difficult sleep initiation.

Hemostasis has been studied in the course of long-term (520 days) isolation in hermetic chamber. Measured parameters included activated partial thromboplastin time (APTT), international normalized ratio (INR), thrombin time (ТT); concentrations of fibrinogen (FBG), plasminogen (PG), Willebrand factor (WF), tissue factor pathway inhibitor (TFPI), tissue plasminogen activator (TPA), and thrombomodulin (ТМ); activities of the coagulation cascade factors II, V, VII, X, VIII, IX, XI, and XII, antithrombin III (ATIII), protein С (PC), С1-inhibitor (С1), α₂-antiplasmin (АP), TPA and TFPI. The investigation revealed a diversity of changes in plasma FBG concentration, slower blood coagulation in the intrinsic pathway and in final stage, and a relative rise in the activities of ATIII and PC-inhibited factors. The remaining parameters exhibited different trends.

In the real-life environment, the subjectively unperceived reactivity of rheoencephalogram (REG) and electroencephalogram (EEG) to ordinary geophysical factors (including wind, atmospheric pressure, relative humidity, and temperature) is gender-dependent. Correlations between REG and EEG values and weather fluctuations are more frequent and stronger in men. Dependence of EEG rhythms on weather factors increases as the rhythmic activity within the δ–θ–α–β range becomes more rapid. This pattern is particularly evident in men but not women. Reactivity of neurodynamic parameters in female REG and EEG is responsive to the ovarian-menstrual cycle. Almost all cases of cerebral weather sensitivity of women were objectified in the post-ovulatory period, whereas in the preovulatory period, episodes of weather sensitivity were few.

Heart rate variability (HRV), hemodynamics, cerebral α rhythm, and systemic relations between them have been investigated in 35 normal human subjects at the age of 37.2 ± 3.8 years. The results of comprehensive clinical, functional and instrumental HRV investigation, electroencephalography (EEG) using 21 monopolar electrodes, and blood pressure (BP) monitoring were embodied in mathematical models that describe the relations of these parameters, multiple regression equations, and generated 3D diagrams. It has been found that a relative increase in the LF range and a decrease in HF one are accompanied by elevations of BP. The EEG α amplitude has been depressed, and α index has decreased. The HRV reduction and modification of the α rhythm structure have been demonstrated to affect the BP values. These data indicate interactions and close relations between the autonomic and central nervous systems and BP.

The purpose of this study was to analyze the characteristics of the reaction of the human spinal column to axial static and dynamic loading. Segments of human column from dorsal vertebra XI to lumber vertebra III were exposed to axial static (20 mm/min) and dynamic (200 and 500 mm/min) loading. The measured variables included the load value, whole segment deformation, deformation of the anterior surfaces of intervertebral disk of Th_XI–Th_XII and dorsal vertebra XII, and acoustic emission signals (indicator of spongy bone microdestruction). It was found that the rate of increase in body deformation is lower than that in the intervertebral disk deformation and that the central parts of the spinal end plate compress greater than the peripheral parts. This difference was larger during static loading than that during dynamic loading. To produce the same deformation of a spinal segment due to dynamic loading as that due to static one, it is necessary to overcome a stronger resistance of a greater number of trabecular bones than that due to static loading. Therefore, it can be concluded that, first, the value of dynamic loading causing the same segment compression should be higher than the value of static loading, and the main practical significance here is that the dynamic strength of the column is markedly higher than the static one; second, spinal hardness during impact is higher than that under the static condition; and, third, the same degree of deformation should result in a larger volume of microdestructions in the case of dynamic loading than that in the case of static loading, which is evidenced by a significant difference in the number of AE signals accumulated prior to fracture. The number of AE signals is 444.2 ± 308.2 and 85.0 ± 36.6 in the case of dynamic and static loading, respectively (p < 0.05 according to Student’s t test).

A mathematical model of the biotechnical system integrating the human cardiorespiratory system with a hard- and software suite (HSS) was designed to investigate breathing control. The model describes the dynamics of carbon dioxide and oxygen in three biotechnical system compartments in the course of rebreathing tests. The tests do not require tanks with compressed gas and, hence, can be performed in space flights. The results of simulated modeling of the ventilation response in two breath tests, i.e., to hypercapnia due to rebreathing hyperoxic gas mixture (HGM) and to hypercapnia combined with hypoxia due to air rebreathing are presented. The model validity was verified by comparison between the modeling and experimental data. The mathematical model made it evident that CO₂ partial pressures in tissues, the lungs, and the breathing circuit equalize very fast when the initial carbon dioxide concentration in the respiration circuit is equal to the end-tidal CO₂ concentration in humans at rest.