Vol 9, No 2 (2023)

INTRODUCTION. Severe climatic conditions, state of the environment, water and air quality and other factors affect human health in the Arctic region, including cardiovascular system. The study of these factors is necessary to create measures to prevent the development of diseases.
OBJECTIVE. Analyze morbidity and mortality from cardiovascular diseases in the Arctic countries as well as risk factors of their development.
MATERIALS AND METHODS. The study analyzed PubMed, Scopus, Web of Science and Google Scholar database over 25 years from 1998 to 2023. The search terms included the keywords: cardiovascular diseases, climate, risk factors, adaptation, morbidity, mortality, Arctic.
RESULTS. It was found that primary morbidity exceeds the all-Russian value 1,4 times in the Arctic region. Mortality by main causes of death for 2015–2019 over a 5-year period tends to decrease. There are similar data in other Arctic countries, including cardiovascular diseases. Mortality rate among Arctic indigenous groups is not the same.
DISCUSSION. Scientists consider the effect of extremely low temperatures and the body’s adaptive capacities, toxic effects of harmful chemicals and insufficiency of vitamin D due to reduced sun exposure to be among health hazards in Arctic, including cardiovascular system. Cardiovascular diseases were noted to be seasonal.
CONCLUSION. Arctic public health depends on many reasons, including the body’s adaptation to extreme habitat conditions, social conditions, ecology, lifestyle and nutrition, availability of medical care and drug provision.

The lecture systemizes modern ideas about the role of stress in the development of neuropsychiatric disorders in people with HIV (PLWH): variety of stress factors, mechanism of their involvement in pathogenesis, main clinical implications, prevention and measures of maintaining mental health. There was the analysis of currently relevant groups of people with chronic stress and various characteristics: demographic, social, age, ethnic, etc., with an increased risk of susceptibility to HIV infection that can lead to additional somatic and behavioural consequences. A special attention is paid to the effect of background psychological stress burden, depression, post-traumatic stress disorder, direct and indirect virologic pathogenic effects of HIV on the human body.
The lecture is intended for a wide range of specialists, participating in planning and implementing prevention programmes, medical, social and psychological support in different populations and workplace.

INTRODUCTION: Searching for an early marker in assessing the severity of community-acquired pneumonia is a global issue in modern medicine. As such a biological marker of community-acquired pneumonia severity, the assessment of telomere length peripheral blood lymphocytes on the day of inpatient treatment may be suggested.
OBJECTIVE: Study prognostic value of telomere length in assessing prognosis of pneumonia severity of different etiology.
MATERIALS AND METHODS: The study involved a group of 97 patients with community-acquired pneumonia of different etiology (viral pneumonia, caused by COVID-19 and bacterial pneumonias). Blood samples were taken on admission and discharge from hospital in accordance with informed voluntary consent. Telomeres were measured in DNA, secreted from peripheral blood lymphocytes, using the manufacturer’s protocol kit (Biolabmix, Novosibirsk).
RESULTS: Depending on the severity, the assessment of telomere length in patients with viral pneumonias showed that in the group 1 at admission the value of this indicator was 6343 (6114; 6422) kilobases, whereas in the second group it was statistically significantly lower - 5264 (5057; 5423) kilobases (p<0.001).
DISCUSSION: The study results showed that all patients with severe viral pneumonia, caused by a new coronavirus infection, after 3 weeks in hospital experienced significant reduction of telomere length not less than 2000 base pairs. Analyzing the data, we managed to confirm the hypothesis of much more severe viral pneumonia in patients with low telomere lengths. CONCLUSION: It was found that telomere length changes significantly in the dynamics of bacterial and viral pneumonia and can be considered as a marker of severity and prognosis of the disease course in the early stages of diagnosis.

INTRODUCTION: The study of the profile fatty acids (FA) as an energy and functional link of physical performance among enforcement agencies seems to be very relevant.
OBJECTIVE: Assessment of the blood FA profile of the body of military before and after a 4-month special duty associated with health and life risks.
MATERIALS AND METHODS: This prospective, between-subjects, repeated measures, study was conducted during 2014 year. 25 OMON fighters of the Komi Republic were examined before the trip and after a 4-month trip to the North Caucasus, where they constantly experienced combat stress. As a comparison group - employees of the Ministry of Emergency Situations (12 man). The level of FAs pool in total blood plasma lipids was determined by gas chromatography.
RESULTS: During the initial examination of OMON fighters, a higher proportion of hypercholesterolemic myristic acid was revealed in both groups relative to the recommended norms. Its level was significantly higher in the special forces group and averaged 1.5 mol% (p = 0.028). The level of essential n-3 polyunsaturated fatty acids (PUFAs) in the blood plasma (α-linolenic and eicosapentaenoic acids) reduced relative to the baseline values in the participants against the background of a high proportion of linoleic acid was established, as evidenced by the high value of the n6/n3 index - 13.8 / 1 at the recommended standards of WHO 5- 7/1. A re-examination of OMON officers conducted after a trip showed a significant decrease in the level of saturated (p=0.040) and essential n-3 docosahexaenoic (p=0.000) and α-linolenic acids (p=0.003) in blood lipids in 92% and 68% of the subjects respectively. At the same time, the proportion of docosahexaenoic acid in the blood negative correlated with the indicator of personal anxiety (r= -0.32; p=0.028).
DISCUSSION: The professional activity of military and the presence of regular psycho-emotional stress most significantly affect the essential part of fatty acids. The conducted study indicates the need to optimize the diet of participants and additional intake of food supplement, n-3 PUFAs enriched.

OBJECTIVE: To study specific features of the invasive telemetry system Stellar in implementing liquid breathing technology under excessive water pressure.
MATERIALS AND METHODS: The study of liquid breathing in hyperbariс conditions was carried out on the hyperbaric stand, providing a simulated immersion/emersion of a laboratory animal up to a depth of 1500 m. Dynamic monitoring of key indicators of the animal’s body functional systems was performed with the patient monitor Dixon Storm 5770 Vet. During bench tests, the frequency of the laboratory animal’s independent breathing, the core body temperature (Тº С), heart rate (HR), electrocardiopraphic research data through invasive telemetry Stellar were recorded in real time.
RESULTS: Before the bench tests the invasive telemetry system Stellar was implanted in the body of the laboratory animal. The process of simulated immersion/emersion of laboratory animals on the hyperbaric stand was 390 sec. at a total immersion time 570 sec. During the bench tests the laboratory animals experienced hypothermia with a rectal temperature 32,1 º С, their breathing after decompression was registered at the level of 28 breaths /min. Bradycardia was recorded at a level of 66-70 beats/min after extracting the laboratory animal from the hyperbaric stand. Under decompression the vast majority of the laboratory animals showed full restoration of the sinus rhythm. At the same time, restoration of the rhythm was not recorded with 2 laboratory animals with ST-segment elevation and depression, provoked by myocardial hypoxia.
DISCUSSION: Under different modes of barometric pressure during liquid breathing on the hyperbaric stand the laboratory animals experienced hypothermia, accompanied by transient ischemic changes in the myocardium, determined by immersion length and depth. Liquid respiratory desaturation under ultra-fast decompression revealed inversely proportional dependence of external respiration function on the basic characteristics of the external environment.
CONCLUSION: The expedience of applying the test hyperbaric stand, which allows to simulate high hydrostatic pressure for imitating immersion/emersion of laboratory animals when studying liquid breathing technology. The bench tests attested indispensability of applying the invasive telemetry system Stellar for monitoring functional parameters of laboratory animals, measuring peculiarities of body’s adaptation in extreme water conditions. Liquid respiratory desaturation under ultra-fast decompression revealed inversely proportional dependence of external respiration function on the basic characteristics of the external environment. Systematic empirical data indicate potential benefit from the invasive telemetry system Stellar in studying liquid breathing under the conditions of hyperbaric stand.

INTRODUCTION: Until recent times, the questions of tooth enamel functional resistance and possibility of its increase on long voyage were not thoroughly investigated that poses medical and social problems in maritime medicine.
OBJECTIVE: To assess the dynamics of tooth enamel functional resistance for seafarers and possibility of its increase on long voyage.
MATERIALS AND METHODS: 49 men aged 19-27 were monitored for 9 months, being periodically examined once a quarter for assessing tooth enamel functional resistance, done by TER test. The seafarers had in-depth examination in the first week of voyage and then every 3 months, i.e. 4 times for each examined seafarer. The first control group included 23 men, who carried out their standard 2-time individual oral hygiene per day on long voyage. The second main study group included 26 seafarers, who additionally used remineralizing tooth gel ASEPTA after individual oral care.
RESULTS: At the voyage start rates of tooth enamel functional resistance to acid were almost the same for the seafarers of the 1st and 2nd groups and were 2,12±0,17 and 2,13±0,17 srvc. units, respectively. On long voyage the seafarers of the 1st group tended to have lower tooth enamel functional resistance up to 2,52±0,12 srvc. units, while the seafarers of the 2nd group experienced significant increase in tooth enamel functional resistance up to 0,79±0,21 srvc. unit, which indicates effectiveness of their using remineralizing tooth gel ASEPTA.
DISCUSSION: The daily use of remineralizing tooth gel ASEPTA by the seafarers of the 2nd main study group on long voyage allowed to increase numerical rating of tooth enamel resistance by 37,1%, being an important factor in preventing the risk of dental caries.
CONCLUSION: On long voyage seafarers experience decline in tooth enamel functional resistance with commonly accepted individual oral hygiene. The use of remineralizing tooth gel ASEPTA allows to improve tooth enamel functional resistance. Thus, its application can be recommended in seafarers’ individual oral hygiene on long voyage.

Sample size calculation is a critical step in planning a research project to obtain valid and generalizable results in biomedical sciences. It enables researchers to reach a balance between time, resources, and ethical considerations when planning and conducting research. Statistical software can assist in calculating sample size, but calculation method depends on the data characteristics and the research question.
This article presents a practical tool for calculating the required sample size for studies that aim to compare measures of central tendency for several research questions using the G*Power software. Sample size calculation for Student’s unpaired t-test, oneway analysis of variance (ANOVA), as well as their non-parametric analogs – Wilcoxon and Mann–Whitney tests are presented. The article walks readers step by step through sample size calculations for the abovementioned situations using practical examples. Therefore, this paper has a potential to become a valuable resource for junior researchers who are at the planning phase of their research. It serves as a practical guide for calculating the required sample size for parametric and nonparametric methods of analysis to test statistical hypotheses about the equality of measures of central tendency in unpaired groups.

Current health indicators of modern schoolchildren, spending more than one third of the day in the educational organization, have negative tendencies. Deterioration of students’ health in recent decades has actualized the need to implement health system requirements in educational organizations, provided for by law № 273-FL (as amended on 01.03.2020) “On education in Russian Federation”. Due to the shortage of healthcare workers at schools, part of the tasks in preserve and strengthening students’ health can be achieved by teachers considering their professional retraining in the system of additional professional education. The study reveals the main areas of teachers’ work for creating health saving environment in the educational organization to implement sanitary and hygienic tasks to promote health of future recruits.