A model of brain ischemia induced by staged ligation of the left and right common carotid arteries has been developed in experiments on rats. The use to this model led to reduction of animal mortality. On days 2-5 after the second ligature, the animals lost weight, the level of their CNS vulnerability increased, the volume of perceived information reduced, adaptation to environmental conditions and reproduction of conditioned reflexes were disordered. Focal and diffuse destructive changes in the nerve and glia cells were found in the cerebral cortex, hippocampus, and thalamic nuclei. The severity of disorders in the blood supply to the brain depended on the interval between ligation of the carotid arteries. This recommends this model for evaluation of the efficiency of drugs of various pharmacological groups.

In 2020 the whole world was faced with an epidemiological outbreak caused by a new coronavirus SARS-CoV-2. The information available to date suggests that the newly isolated SARS-CoV-2 coronavirus should be assigned to superantigens, the main manifestations of which, as it is known, are suppression of nonspecific resistance factors and suppression of innate immunity mechanisms associated with the formation of a systemic inflammatory response in the form of cytokine storm and pathological activation of phagocytes in the lung tissue with its alteration and subsequent fibrosis. In this case, it is quite difficult and sometimes even impossible to observe the formation of fully-fledged specific immune answer on the effect of such antigens. This, along with the high infectious nature of the disease and the associated mortality, requires special attention to the underlying immunopatomechanism(s). Perhaps that is why little information has been obtained regarding the immunogenic properties of the newly isolated SARS-CoV-2 coronavirus so far, as well as, most importantly, about the structures of the virus itself responsible for the formation of specific immunity to it. The latter will serve as the basis for patient management and vaccine development. Nevertheless, a certain point of view on this issue is already beginning to form, as tools for detecting specific antibodies are being actively developed, as well as modern diagnostic tests for coronavirus, which include real-time polymerase chain reaction, real-time reverse transcription polymerase chain reaction and isothermal amplification mediated by reverse transcription. The presented analysis makes it possible to expand the understanding of the issue concerning the immunopathogenesis of COVID-19, the mechanisms of the onset and development of the disease in a living organism, the formation of an immune response to the new coronavirus, and also to determine the therapeutic tactics of managing patients with severe coronavirus infection. Elucidating the mechanisms of the emergence and development of a new coronavirus infection can help scientists, general practitioners, clinicians, and laboratory physicians respond correctly to the COVID-19 pandemic.

A number of clinical studies demonstrate that individual characteristics such as stress tolerance and cognitive ability can be considered not only as diagnostic variables but also as risk factors for severe cerebral hypoperfusion. The aim of the study was to identify the typological features of the effect of physical activity on the behavioral reactions of rats during cerebral hypoperfusion. Material and methods. Cerebral hypoperfusion was modeled by bilateral carotid artery ligation. The study involved 280 rats, divided into equal subgroups, according to sex, stress tolerance and learning capacity. Of these, 112 animals were subjected to daily short-term swimming as a rehabilitation model. Before the simulation, and at 6, 8, 14, 21, 28, 35, 60 and 90 days postoperatively, the animals were tested using a Morris water maze and an “open field” test. Results and discussion. The dynamics of stress resistance and learning ability are related to the periodicity of inflammatory, necrotic, circulatory and reparative remodeling in the model used. After 2-3 months of study, cerebral hypoperfusion causes stabilization of indices characterizing stress resistance and cognitive functions below control values. A decrease in stress resistance begins earlier from day 6 of the study, while the index characterizing cognitive functions first decreases significantly after 3 weeks of study. Factors reducing the damaging effects of cerebral hypoperfusion were female gender, high baseline stress tolerance and learning ability. When assessing learning ability under physical load, animals with high baseline cognitive development showed earlier recovery dynamics during urgent adaptation and a significant increase during long-term adaptation.

Introduction. Currently, there is an increasing need for the study and development of the World Ocean, including for the purpose of laying deep-water pipelines, searching for new sources of minerals, etc. The performance of special tasks by divers at great depths has its own characteristics. The high cost of error, harmful working conditions - all this dictate the need for continuous receipt and analysis of scientific material on the preservation and promotion of health, ensuring their longevity, as well as the adaptation of divers to the nature and conditions of professional activity in order to prevent the occurrence of errors. The study aims to explore the functions of attention and thinking of a person, his fine muscular coordination and subjective assessment of the state of the body of divers, as elements of the functional state of the body, when working underwater. Materials and methods. We examined 18 divers, divided into two groups: the first - ten people made daily descents to a depth of 18 m, the second group - eight people dived to a depth of 56 m. Before and after diving, the divers underwent a psychophysiological examination to assess the function of attention (the method of the correction test with Landolt rings), the function of thinking (the method of the arithmetic test "addition in mind"), fine muscle coordination (the method of macrography) and subjective assessment of the state (the SAN questionnaire (state of health - activity-mood)). Results. During diving operations, there was a decrease in subjective self-assessment of the state of the body (SAN test), an increase in the number of errors (correction test with Landolt rings - attention function) and the values of the height index of numbers (macrography technique - fine muscle coordination), a decrease in the speed of thinking depending on the depth, the multiplicity of diving descents, as well as the dive itself (regardless from depth and multiplicity) on the functional state of divers. There were most pronounced changes during prolonged work (3-5 days or more) and when diving to a depth of 56 m. Conclusion. The dynamics of objective indicators and subjective assessment of the state of the body indicates that with an increase in the depth of immersion (from 18 to 56 m), the multiplicity of diving descents (daily immersion for 5 days) and the dive itself, the self-esteem of the state, the speed of thinking, attention, fine muscle coordination decreases. Ethics. The study was conducted in compliance with the Ethical principles of conducting medical research with human participation as a subject, set out in the Helsinki Declaration of the World Medical Association.

Today, there are personal protective equipment, which due to their weight and size characteristics and design features can aggravate professional activity. This is characterized by an increase in the load on several major systems of the employee's body, including the cardiorespiratory system, which can cause the development of occupational pathology. The study of the functions of the cardiorespiratory system of humans in the process of his work is an important task in biomedical tests such as PPE, aggravating their professional activities and future means of individual protection from heavy labor and industrial exoskeletons. The aim of the study is to determine the possibility of using ergospirometry for the physiological assessment of personal protective equipment and industrial exoskeletons. Main part. In medical practice and high-performance sports, ergospirometry is considered the "gold standard" for functional assessment of the cardiorespiratory system. There are very few studies showing the use of ergospirometry for the purpose of physiological assessment of personal protective equipment. Results of research works in which ergospirometry was used in medicine, sports, as well as on the physiological and hygienic assessment of combat equipment, various types of personal protective equipment, including new promising personal protective equipment of the musculoskeletal system-industrial exoskeletons. The use of ergospirometry made it possible to register the main indicators of the human cardiorespiratory system both in field and laboratory conditions and allowed forming an objective conclusion about the dynamics of the degree of stress of the human cardiorespiratory system when using personal protective equipment and industrial exoskeletons with various weight and size characteristics. Thus, the use of ergospirometry both in isolation and in combination with other methods allows us to solve problems related to biomedical testing of personal protective equipment and industrial exoskeletons.

The essence of the preconditioning effect is the activation of urgent defense mechanisms of adaptation as a result of a short episode of weak, non-damaging hypoxic or ischemic exposure, which contributes to an increase in the tolerance of the subsequent delayed, more severe exposure to hypoxia or ischemia. Aim of the study was to assess the literature data on the possibility of using the method of remote ischemic preconditioning (RIP) as a non-pharmacological method for correcting physical performance. Material and methods. In the Scopus, PubMed and eLibrary databases, a selection and analysis of modern literature sources devoted to the issues of increasing human performance, especially by nonpharmacological methods, as well as the use of distant preconditioning to increase physical performance and the mechanisms for implementing this effect, were carried out. Results. Since the discovery of the phenomenon until now, researchers have considered RIP, mainly as a way to protect organs and cells from ischemic damage in clinical practice. The article presents the literature data on the use of RIP as a non-drug method for improving physical performance with single and course use cases. In addition, the article focuses on the mobilization of the body’s own resources through the mechanisms of adaptation to hypoxia developing during RIP. Conclusions. Among the non-pharmacological methods of increasing physical performance, one of the most promising, in our opinion, is RIP that mobilizes the body’s own resources through the mechanisms of adaptation to hypoxia. The advantage of the method based on short-term cessation of blood circulation in the lower extremities and subsequent reperfusion does not apply to the ways prohibited in sports, does not require the use of drugs and the availability of special equipment, signifcant costs of economic and organizational resources.

We studied the effects of 2-(hexyl(methyl)amino)methyl)pyridyl-3-dimethyl carbamate (OPDC), a structural analogue of aminostigmine oxalate, on memory formation in rats with toxic scopolamine-induced amnesia. It was shown that OPDC in non-toxic doses ((1)/215 LD50) has significant anti-amnesic action. Ipidacrine and galantamine in the doses similar to toxic doses ((1)/17 and (1)/6 of LD50, respectively) induced the retention of memory trace. Administration of aminostigmine ((1)/11 of LD50) induced unstable anti-amnesic effect in the model of scopolamine-induced amnesia.

Introduction. From 1960 to 2018, 282 people were enrolled in cosmonaut groups in the USSR and Russia. Extreme special training and working conditions could lead to health disorders, which may be reflected in the causes and rates of mortality in the future. The goal of this work is to study the causes and rates of mortality in two cohorts of cosmonauts: those with and without spaceflight experience. The study aim is to research the causes and mortality rates of astronauts who have made and did not fly into space. Methods. A cohort study of mortality of 263 male cosmonauts was conducted, 118 cosmonauts with spaceflight experience formed cohort 1, 145 cosmonauts without it - cohort 2. The follow-up period was 59 yrs. (01.01.1960-31.12.2018) with 8351,4 person-years obtained. The reference group for both cohorts was the male population of Russia, cohort 2 was also the reference group for the cohort 1. Mortality risk was assessed using standardized mortality ratio (SMR) with 95% confidence interval (95% CI). Results. Death risk from all causes (A00-Y98) for each cohort was significantly lower than that for the male population (SMR=0,39, 95% CI 0,28-0,54 for cohort 1; SMR=0,53, 95% CI 0,41-0,69 for cohort 2). Moreover, the risk of death for cosmonauts with spaceflight experience is also lower than for cosmonauts without it (SMR=0,66, 95% CI 0,46-0,91). The most common causes of death in both cohorts were circulatory system diseases, and cosmonauts without spaceflight experience died at a younger age. Conclusion. Further research is required to understand the true influence of extreme working conditions on cosmonauts’ health, especially in the long-term period.