TOXOPLASMA GONDII AS A FACTOR OF PROGRESSION OF CARCINOGENIC PROCESSES AT THE MOLECULAR-GENETIC LEVEL IN AN INTERMEDIATE HOST

Objectives. To study Toxoplasma gondii as a factor of carcinogenic processes progression at the molecular-genetic level in an intermediate host. Material and methods. In the experiment, the expression of the proto-oncogenes survivin (BIRC5), epidermal growth factor (ErbB-2/HER2-Neu), GLI, vascular endothelial growth factor (VEGF) and anti-oncogene TP53 was determined in comparison with the reference genes - β-actin (ACTB) and GAPDH by means of PCR analysis in the tissues of animals with C6 tumor in situ infected with toxoplasma in different doses. A statistical comparison was made between the data of the experimental groups, depending on the dose of infection and the stage of the parasite development. Results. It has been revealed that toxoplasma can cause an increase in the expression of survivin (BIRC5), VEGF, ErbB-2/HER2-Neu, GLI in the tumors, lungs, liver, spleen, brain, both when invaded at a dose of 25 toxoplasma tachyzoites per 1 g of body weight (5000 tachyzoites per female) and when infected at a dose of 50 toxoplasma tachyzoites per 1 g of body weight (10000 tachyzoites per female). The degree of an increased expression of proto-oncogenes is directly dependent on the dose and stage of the parasite development. Infection of female rats having glioma with toxoplasma tachyzoites leads to a decrease in the expression of the anti-oncogene TP53 in the tissues of glioma, the lungs, liver, spleen, and brain of female rats. The decrease in the expression of TP53 depends on the dose of infection and the stage of toxoplasma development. Conclusions. Experimental toxoplasmosis causes an increase in the expression of BIRC5, ErbB-2/HER2-Neu, GLI, VEGF and a decrease in the expression of the anti-oncogene TP53, which can lead to the development of aggressive blastomogenic processes in mammalian tissues.

THE SURFACTANT SYSTEM OF THE LUNGS. A REVIEW ARTICLE

This article contains the information about the structure, functioning, and regeneration of type 2 pneumocytes. The composition of the surfactant, the processes of its synthesis, formation, secretion, distribution and redistribution of its components, as well as the biological role of the surfactant in the functioning of the lungs are described in detail. The information about the development of the surfactant system of the lungs during embryogenesis is also included. Objectives. To review modern literature on the structure and functions of the surfactant system of the lungs, the organization and structure of the surfactant, the mechanism of surfactant formation, the embryogenesis of the respiratory section, to characterize the structure and processes of the functioning of type 2 pneumocytes, as well as the processes of synthesis and secretion of the surfactant, its biological role in the functioning of the lungs. The relevance of the chosen topic is connected with a high level of the respiratory system pathology including a high incidence of respiratory system organs diseases in early childhood, associated with an insufficient level of the surfactant maturity. The problem of pulmonary pathology in newborns, including premature babies, largely determines the level of infant morbidity and mortality.

PREVENTION OF PSYCHOACTIVE SUBSTANCES USE AMOUNG SCHOOLCHILDREN

The article describes the relevance and necessity of primary prevention of psychoactive substances use among schoolchildren, considers the need for scientific substantiation and evidence of the effectiveness of the use of programs for the prevention of psychoactive substances use in different countries. A short literature review of the experience of primary prevention of the use of psychoactive substances in Belarus, Russia and the non-CIS countries has been made. The elaborated, tested and implemented in practice curriculum of optional classes aimed at the formation of students’ skills of responsible and safe behavior «We are ourselves» for grades 5-8 of general secondary education establishments is presented in detail. The goals of the extracurricular program as well as its structure are described, and its tasks are detailed. The organizational and methodological work that was carried out for the successful implementation of the cycle is highlighted (seminars with educational psychologists, individual consultations on request, summing up intermediate results after 5 lessons and a seminar on the final stage of testing methodological materials and definitive results). The primary results on the program effectiveness are given, that were obtained with the help of a survey of students, their parents and teachers, as well as the results concerning the distribution and implementation of monitoring the curriculum «We are ourselves» in Vitebsk region, which demonstrated its relevance and the prospects for its use. Based on the results of the article, the conclusions are drawn about the effectiveness of prophylactic work with schoolchildren to prevent the use of psychoactive substances and methods of its improvement.

THE IMPACT OF THE FOOD ADDITIVE E407A ON THE METABOLIC ACTIVITY OF DIFFERENT CELL CULTURES

Objectives. To study the effects of various concentrations of the food additive E407a (semi-refined carrageenan) on the metabolic activity of fetal liver cells, splenocytes, and bone marrow cells. Material and methods. Fetal liver, splenocytes and bone marrow cell cultures were incubated with the food additive E407a at concentrations varying from 0 mg/ml to 10 mg/ml for 24 hours (n=8). To analyze the effects of this food additive on the metabolic activity of cells, a colorimetric MTT assay was used. It is based on the ability of viable, metabolically active cells to convert 3 (4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide into formazan. The data were statistically processed using Kruskal-Wallis and Dunn’s criteria. Results. The bone marrow cell culture was found to be the most sensitive to carrageenan. More than a twofold statistically significant (p<0.0001) increase in the metabolic activity of bone marrow cells was observed when using E407a from 200 μg/ml and above. The metabolic activity of splenocytes increased approximately 1.5 times and over (p<0.0001) when using carrageenans at the concentration of 500 μg/ml and higher. Fetal liver cells turned out to be the most resistant to the direct toxic effect of the food additive E407a. Conclusions. The food additive E407a is cytotoxic to bone marrow cells and splenocytes at concentrations of 200 μg/ml and 500 μg/ml, respectively.

RESEARCH ON THE IMPACT OF PARTICIPATION IN THE WORK OF MEDICAL INSTITUTIONS RENDERING ASSISTANCE TO PATIENTS WITH COVID-19 ON THE STUDENTS’ PROFESSIONAL SELF-IDENTIFICATION

Objectives. To study the impact of participation in the work of medical institutions providing assistance to patients with COVID-19 on the professional self-identification of students. Material and methods. The study was carried out on the basis of the educational institution «VSMU». Inclusion group: medical students of the 4th-6th years who took part in the work of medical teams providing assistance to patients during the period of an epidemic rise in the incidence of respiratory infections, including SARS-CoV-2 coronavirus one. The survey was conducted in the form of an anonymous questionnaire. To segment the respondents according to certain criteria, depending on their answers, the «decision tree» method was used. Results. In the course of the study, it has been found that 1.8 times more often the question «To what extent did you manage to combine your work and studies?» the answer «everything turned out well» was given by the students who indicated that they had a curator who helped them to cope with their professional adaptation difficulties. The higher the self-esteem of the personal level of knowledge and skills was, the more often students chose the answer that they were definitely not going to leave medicine and change their profession. Conclusions. Based on the survey data, one of the most significant factors influencing the adaptation and development of practical skills is the high-quality work of university teaching staff and a physician-curator. An important role in professional adaptability is played by the solution of psychoemotional problems of working students through the establishment of their close interaction with the social, pedagogical and psychological service of the university, professional training centers.

TISSUE SEALING MEDICINAL AGENTS GROUP ON THE PHARMACEUTICAL MARKET OF THE REPUBLIC OF BELARUS

The purpose of this article was to analyze the pharmaceutical market of the tissue sealing agents group of the Republic of Belarus from 2010 to 2018 based on the data presented in the Medmarket database and the State Register of Medicines of the Republic of Belarus of UE «Center of Expertise and Testing in Healthcare». The group of tissue sealing agents (B02F) was found to be characterized by high growth rates and a relatively large market share. During the studied period, it was represented on the Belarusian pharmaceutical market by only one drug - Tachocomb (manufactured by Takeda Pharmaceutical Company Limited, Japan). When analyzing its dynamics in the period from 2010 to 2018 it was found that, in general, the change in the volume of the market for tissue sealing agents correlates with the change in the volume of the total market for hemostatic drugs over the years. During 2010-2018 there is an increase in the volume of sales for this local sealant, both in monetary (by 1.51) and in natural (by 2.01) expressions with a gradual fall of the price. It has been concluded that the development of the tissue sealing agents by domestic manufacturers is urgent and expedient.

THE ADMINISTRATION OF FISH OIL TO PREGNANT RATS AGAINST THE BACKGROUND OF STRESS PREVENTS THE DISORDERS OF NITRIC OXIDE FORMATION AND ACTION IN OFFSPRING

Objectives. To assess the possibility to prevent the disturbances of nitric oxide (NO) formation and action system in prenatally stressed rats with the help of fish oil administered to their mothers during pregnancy against the background of stress. Material and methods. Outbred pregnant rats weighing 180-220 g were divided into equal groups (n=10): «Pregnant control», «Pregnant stress», «Pregnant control + fish oil», «Pregnant stress+fish oil». Stress was reproduced by exposure to stressors on different days of pregnancy: food deprivation during one day, contact with cats’ feces during one day, and immobilization in water (20 minutes, t°=23±2). Rats of the groups «Pregnant control + fish oil» and «Pregnant stress + fish oil» received 0.1 ml of fish oil (Biosola, Lithuania) as a gavage at a daily dose of 60 mg/kg of eicosapentaenoic and docosahexaenoic acids; rats of groups «Pregnant control» and «Pregnant stress» received an equivalent volume of starch solution (0.1 ml). In 3-month-old offspring (n=181), systolic, diastolic, and mean arterial pressure (SBP, DBP, MAP, respectively) were measured noninvasively; the concentration of endothelial and inducible isoforms of NO-synthase (eNOS and iNOS, respectively), cyclic guanosine monophosphate (cGMP), asymmetric dimethylarginine (ADMA) was determined in blood serum by ELISA; the content of nitrates/nitrites (NO₃^-/NO₂^-), diene conjugates (DC), malondialdehyde (MDA), superoxide dismutase (SOD) and catalase was determined spectrophotometrically in blood serum. Results. Fish oil which was administered to pregnant rats under stress led to the increase of reduced compared with control males content of eNOS, cGMP, SOD, catalase, NO₃^-/NO₂^- (by 10.7%, 48.3%, 62.6%, 31.3%, 91.7%, respectively); the decrease of increased concentration of iNOS, ADMA, DC, MDA (by 21.8%, 37.4%, 61.2%, 75.9%, respectively) in the blood serum of male offspring. In female offspring of group «Pregnant stress + fish oil» the decrease of increased content of iNOS, DC, MDA (by 25.8%, 2.6 and 4.9 times, respectively) with the increase of reduced concentration of NO₃^-/NO₂^-, SOD (by 84.6%, 52%, respectively) were determined in the blood serum. The introduction of fish oil to pregnant rats against the background of stress prevented SBP, DBP, and MAP increasing in the offspring. Conclusions. The administration of fish oil to rats during pregnancy under chronic stress prevents the impairment of NO production and action in the offspring.

PARKINSONISM SYNDROME FORMATION IN EXPERIMENTAL ANIMALS. NEUROINFLAMMATORY PENUMBRA

Much valuable information about the development of Parkinson’s disease (PD) has been obtained from studies on the laboratory animals. Objectives. To compare the development of neurotoxic and neuroinflammatory parkinsonism syndrome in laboratory animals. Material and methods. The number of rats in the group of neuroinflammatory model of parkinsonism syndrome (lipopolysaccharide) was 6, and in the group of neurotoxic model (rotenone) - 20. The control group consisted of 5 animals. The study was approved by the independent Ethics Committee. The development dynamics of parkinsonism syndrome of neurotoxic and neuroinflammatory genesis was assessed in the study of the motor activity of animals, as well as in the laboratory study of biomarkers of dopamine metabolism (dopamine and homovanillic acid) in blood serum and cerebrospinal fluid obtained in 7 and 21 days after the first administration of rotenone or lipopolysaccharide, and also after a single intravenous injection of allogeneic (rat) multipotent mesenchymal stromal cells (MMSC) carried out after 9 injections of rotenone. Results. A decrease in the levels of dopamine and homovanillic acid has been shown in laboratory animals on the development of Parkinson’s syndrome. In rats with a neuroinflammatory model of parkinsonism syndrome, a pre-motor stage of motor disorders development has been laboratorially confirmed. During the first weeks after the introduction of MMSC, regression of the motor symptoms of neurotoxic parkinsonism syndrome and a parallel increase in dopamine and homovanillic acid are determined. Conclusions. The effectiveness of MMSC in the early post-transplantation period is associated with the paracrine effect. It is proposed to call activated microglia, a potential therapeutic target in PD, neuroinflammatory penumbra.

APPROACHES TO OPTIMIZING PHYSICAL ACTIVITY FOR PEOPLE WITH HEREDITARY DISORDERS OF THE CONNECTIVE TISSUE

The aim of the study was to assess the morphofunctional state and the level of motor activity of young people with phenotypic signs of hereditary connective tissue disorders. The study involved 320 students studying at the educational institution «Polessky State University» at the age of 17 to 20 years. In the course of the study the quantitative characteristics of the occurrence of phenotypic markers of hereditary connective tissue disorders in young people were determined, the functional characteristics of the body were estimated using anthropometry indicators, a functional test with dosed physical activity, and the level of motor activity of the subjects was assessed. As a result of the study, a high incidence of external signs of hereditary connective tissue disorders was revealed (in 39.1 % of the studied young people). The revealed functional features of the body of individuals with phenotypic manifestations of hereditary connective tissue disorders are expressed in an unfavorable reaction of the cardiovascular system to physical activity, unsatisfactory indicators of adaptation of functional systems, and a low level of motor activity. The carried out analysis of the data on the functional state of individuals with phenotypic manifestations of hereditary connective tissue disorders allows us to choose the optimal criteria for differentiating physical activity based on the identified features and functional disorders.

THE ANALYSIS OF POSSIBILITIES FOR INCREASING THE QUALITY OF EDUCATION BY MEANS OF GAME TEACHING METHODS

The aim of this article was to analyze the possibilities of improving the quality of medical education by means of using game teaching methods. The article discusses the nature and causes of the crisis phenomena in higher medical schools observed during the recent decades. A comparative assessment of the proposed ways to improve the quality of medical education is given. The analysis of the existing trends in the field of increasing the efficiency of the educational process has shown that game methods of teaching, which lack excessive formalization and fully contribute to the disclosure of the creative potential of a student, can become a promising solution to this problem. Educational games simulate real clinical situations that are unattainable in the course of the educational process. The educational game provides a variety of possible decisions that have to be made in high degree of uncertainty situations. A game technique of knowledge control in the clinical anatomy of ear, nose and throat has been proposed and tested. The methodology of a game for two teams within the frames of a given game scenario with a simple and sound method of result assessment has been developed.