Noninvasive and Invasive Study of the Pumping Function of Rat Heart in Myocardial Infarction.

The cardiohemodynamics was studied 2 and 4 weeks after myocardial infarction modeling in Wistar rats. We compared the data obtained by echocardiography (echoCG) and catheterization of the left ventricle. The myocardial infarction was modeled by ligation of the left anterior descending coronary artery. EchoCG and the left ventricle catheterization were performed before and after myocardial infarction modeling. Similar results were obtained by both methods, namely the left ventricle dilatation, bradycardia, a reduced ejection fraction and delayed relaxation. According to echoCG, the end-diastolic left ventricle volume increased by 2 times, and initial diastolic left ventricle volume - by more than 5 times. The left ventricle catheterization showed lower rise, by 32 and 69%, respectively. The overestimated volume of the left ventricle in myocardial infarction according to echoCG data in comparison with catheterization can be explained by changes in the geometry of the ventricle (bulging of a part of the ventricular wall).

Suprastin (Chloropyramine) Causes Proarrhythmic Deterioration of Excitation Conduction, Depolarization and Potentiates Adrenergic Automaticity in the Pulmonary Veins Myocardium.

A number of pharmacological drugs have side effects that contribute to the occurrence of atrial fibrillation, the most common type of cardiac rhythm disorders. The clinical use of antihistamines is widespread; however, information regarding their anti- and/or proarrhythmic effects is contradictory. In this work, we studied the effects and mechanisms of the potential proarrhythmic action of the first-generation antihistamine chloropyramine (Suprastin) in the atrial myocardium and pulmonary vein (PV) myocardial tissue. In PV, chloropyramine caused depolarization of the resting potential and led to reduction of excitation wave conduction. These effects are likely due to suppression of the inward rectifier potassium current (IK1). In presence of epinephrine, chloropyramine induced spontaneous automaticity in the PV and could not be suppressed by atrial pacing. Chloropyramine change functional characteristics of PV and contribute to occurrence of atrial fibrillation. It should be noted that chloropyramine does not provoke atrial tachyarrhythmias, but create conditions for their occurrence during physical exercise and sympathetic stimulation.

The Structure of Left Ventricular Relaxation in Case of Ventriculography.

AIM: To study the relaxation structure of the left ventricle (LV) in patients who underwent ventriculography. MATERIAL AND METHODS: LV ventriculography was performed in 37 patients. Before catheterization, echocardiography was performed in each patient. In 6 patients, the LV ejection fraction (EF) was below 40%; these patients with systolic dysfunction were not included in the study. In 31 patients, the LV EF was higher than 50%. In this group, 13 patients had NYHA functional class (FC) 2-3 chronic heart failure (CHF); the rest of the patients had FC 1 CHF. Eighteen of 31 patients had stable ischemic heart disease; 50% of these patients had a history of myocardial infarction; the rest of the patients had hypertension and atrial and ventricular arrhythmias. The dynamics of the LV pressure decrease was analyzed from the moment of the maximum rate of pressure drop, which usually coincides with the closure of the aortic valves. The pressure drop curve was logarithmized with natural logarithms and divided into 4-5 sections with different degrees of curve slope. The relaxation time constant was calculated for each section. Its inverse value characterizes the relaxation time constant (tau). RESULTS: In 31 patients with LV EF 52-60%, three types of the dynamics of the relaxation rate constant were identified during the pressure decrease in the isovolumic phase: in 9 patients, the isovolumic relaxation constant (IRC) steadily increased as the pressure decreased; in 13 patients, it continuously decreased; and in 9 patients, the dynamics of IRC change was intermediate, with an initial increase followed by a decrease. CONCLUSION: In diastolic dysfunction, one group of patients had an adaptation type associated with an increase in the LV wall elasticity, while the other group had a different type of adaptation associated with its decrease. Each type has advantages and disadvantages. This is probably due to changes in the structure of the sarcomeric protein connectin (titin).

The Role of Arterial Elasticity in Determining the Degree of Chronic Heart Failure in Myocardial Infarction.

Aim      To study the left ventricular (LV) contractile and pumping function during the recovery phase following ligation of the anterior descending coronary artery (CA).Material and methods  Cardiodynamic parameters were studied in Wistar rats 2-4 weeks after experimental myocardial infarction (MI). MI was induced by ligation of the anterior descending CA under zoletil anesthesia. LV catheterization was performed with a standard FTH-1912B-8018 PV catheter inserted into the LV through the right carotid artery.Results After the induction of MI, the mortality rate of animals was 50%. Survived animals developed significant LV dilatation and a decrease in ejection fraction (EF) by an average of 31%. However, major indexes of the pumping function, including minute volume, heart work, and maximum ejection velocity, were within a normal range whereas the maximum filling velocity was almost doubled. Approximately 50% of hearts with dilated LV had normal EF, delayed relaxation, and increased LV diastolic pressure, which qualified this group as a diastolic dysfunction group. The systolic dysfunction group with EF less than 50% of normal had similar values of myocardial contractility and relaxation but differed from the diastolic dysfunction group in more than 50% reduced maximum LV ejection velocity and 1.7 times increased elasticity of the arterial wall. A close inverse correlation was found between these values (r= -0.91).Conclusion      The study results showed that, with a similar myocardial contractile function, the cardiac pumping function is determined by the elasticity of the aortic wall. Therefore, restriction of reactive fibrosis during MI is an important task of modern cardiology.

[The content of zinc and selenium in local food products of Yakutia].

Deficiency of the necessary complex of micronutrients under abnormal nutrition structure creates a problem for the preservation of health and performance of the population. In this regard, it is very relevant to develop a science-based strategy for the consumption of traditional Yakut national food that have a high nutritional value and are able to satisfy the requirements of the human body in micronutrients. The purpose of the research was to investigate the content of selenium and zinc in the local foods which are most commonly consumed by the population of Yakutia. Material and methods. The objects of study were meat (7-9 cuts each) and offal (9-11 species each) of the Yakut cattle breed (2 bulls at the age of 2.5 years), of the Yakut horse foals (3 heads at the age of 6 months), northern domestic deer (3 heads), and whitefish (Coregonus muksun), Yakut crucian carp (Carassius carassius jacuticus), lake minnow [Phoxinus percnurus (Pallas)] (3 kg each). The trace elements, zinc and selenium, were determined by infrared spectroscopy. Results. The greatest amount of zinc in the meat of farm animals was noted in the meat of Yakut cattle (6.8±0.3 mg/100 g) and Yakut horse foals (6.7±0.2 mg/100 g), and the lowest - in the meat of domestic reindeer (1.5±0.1 mg/100 g). In terms of selenium content, the meat of domestic reindeer had the highest indicators (37.0±1.0 µg/100 g), and the meat of Yakut cattle had the lowest (19.0±0.8 µg/100g). The highest concentration of zinc and selenium was found in by-products of reindeer: zinc level in the heart and liver was 12.8 mg/100 g, in the small intestine and rennet - 19.0-20.4 mg/100 g, selenium level in the colon and rennet was 41.0-46.7 µg/100 g. The content of zinc and selenium in the fresh-water muksun belly (2.14±0.08 mg and 45.0±1.8 µg in 100 g) was 32.3-37.2% higher than in the fillet of muksun, and selenium level was 3 fold higher than in the Yakut carp and in the lake minnow. The consumption of 100-200 g of meat or by-products of Yakut cattle, Yakut horse foals, by-products of reindeer or Yakut crucian carp can fully cover the daily requirement of an adult in zinc. The consumption of 200 g of venison or muksun completely covers the daily need for selenium, while the portion of the other studied products contains about half or more of recommended daily intake of this trace element. Conclusion. The data presented in the article show that the population of Yakutia, with a rational diet with local products, can meet the requirements in selenium and zinc in accordance with physiological needs.

[The effect of applying clinical organizational telemedicine technology management of anti-tuberculous care on dynamics of tuberculosis morbidity and mortality].

The tuberculosis is the most important medical and social problem among globally dangerous epidemiological phenomena. the tuberculosis ranks 9th place in the structure of mortality and disability of population and 1st place among causes of death from single infectious agent.The purpose of the study was to analyze dynamics of total morbidity and mortality because of tuberculosis against the background of the implementation of telemedicine clinical organizational technology in phthisiology care 2007-2021.The official Regional and Federal data of Rosstat for 2007-2021 were used. The indicators of total morbidity and mortality of population caused by tuberculosis in the Sverdlovsk Oblast were established. The research methods were content analysis, dynamic series analysis, graphical analysis, statistical differences analysis.In the Sverdlovsk Oblast, the morbidity and mortality of tuberculosis exceeded national average indicators by 1.2-1.5 times. In 2007-2021, as a result of implementation of clinical organizational telemedicine technology in managing phthisiology care, total morbidity and mortality of population caused by tuberculosis decreased up to 2.275 and 2.97 times respectively. The rate of decrease of analyzed epidemiological indicators generally correlated with national average data with statistical validity of difference t≥2.In regions with unfavorable epidemiological indicators of tuberculosis, application of innovative technologies in management of clinical organizational processes is required. The development and implementation of clinical organizational telemedicine technology for managing regional phthisiology care contributes to significant reduction of morbidity and mortality of tuberculosis and optimizes sanitary and epidemiological well-being.

THE OCCURRENCE OF SPORTS INJURIES AMONG PRE-ADOLESCENTS.

Preschool children's harmonious development, cognitive and communicative abilities are enhanced through physical activities in sports, yet sports training and competition pose a risk of injury to children aged three to seven years due to their physiological and psychological features. Although sports injuries in preschool children are not common, they can be undesirable and unavoidable, and fortunately, these injuries are usually reversible. This review article presents data on the physiological features of the developing musculoskeletal system and its relationship to sports injuries in children, which together determine the nature of children's sports injuries. We also present a classification of sports injuries among preschool children, based on the literature, which considers the type, location, and severity of the trauma as estimated by the duration of mandatory missed practice.

THE INCIDENCE OF SPORTS INJURIES AMONG SCHOOL-AGED CHILDREN AND ADOLESCENTS.

It is estimated that approximately one in ten school-aged children experience sports-related injuries annually. These injuries are most common at 12 years of age. Boys are more likely to get injured and more likely to get seriously injured than girls. The probability of injury is greater in contact or high-impact sports, with American soccer accounting for the largest number of injuries, followed by wrestling, basketball, soccer, and baseball. In certain sports, such as horseback riding, women are four times more likely to sustain injuries. The presented literature review details the incidence of various sports-related injuries in adolescents. Sports-related injuries observed in children under the age of 10 are nonspecific and include contusions, mild sprains, and fractures of the extremities, most commonly Salter-Harris fractures (growth plate fractures) or plastic fractures. In young athletes, sports-related injuries of the ligaments or muscles, as well as spinal or head injuries, are rare. This is particularly true during puberty, where growth plate fractures and musculoskeletal injuries occur more frequently.

MEDICAL AND SOCIAL ASPECTS OF PREVENTING SPORTS INJURIES AMONG CHILDREN AND ADOLESCENTS.

Sports injuries among children and adolescents typically involve mild bruises and sprains. However, any sport can cause injuries to the musculoskeletal system. It is crucial to prevent such injuries through proper training and supervision to ensure the safety of young athletes. Therefore, when providing medical care to these patients, physicians must have the appropriate qualifications and skills and take into account the specific nature and location of injuries in each sport. Training programs and performance standards for young athletes should consider participants' biological age, physical and psychological immaturity, rather than their chronological age to prevent serious musculoskeletal injuries in child and youth sports. This review outlines the incidence of sports injuries in adolescents and considers how biological and social factors (factors related to coaches, peers and parents), influence the incidence and nature of injuries in different sports. Coaches and parents, though, have the ability to reduce the risk of injury by selecting suitable sports activities, employing the right equipment, enforcing rules, promoting safe playing conditions, and ensuring adequate supervision. Healthcare providers involved in the prevention and treatment of injuries in young athletes must possess the skillset to diagnose and assess the severity and risk to the athlete's future health and performance.

HEMODYNAMICS AND CARDIAC CONTRACTILE FUNCTION IN TYPE 1 DIABETES.

The cardiohemodynamics was studied 1 week after the administration of streptozotocin (60 mg / kg) or 2 weeks after a dose of 30 mg / kg. All rats had a significantly elevated level of glucose in the blood (up to 27-31 mM). In an echocardiographic study, about 1/3 of diabetic animals exhibited systolic dysfunction, and the remaining 2/3 - diastolic dysfunction with an increase in isovolumic relaxation time by 1.5 times. The catheterization of the left ventricle (LV) with a sensor that allows simultaneous measuring LV pressure and volume in both groups revealed decreased cardiac output by 25-31% and maximal ejection rate by 34-50%. However, LV developed pressure, the maximal rate of its development and the level of blood pressure remained within the control values, thus reduced LV ejection rate was probably due to increased arterial stiffness - a negative correlation was found between these indicators (r = - 0.70). The diastolic dysfunction group differed from systolic dysfunction by a significantly smaller end diastolic volume by 22%. Thus, in type 1 diabetes, LV remodeling with reduced end diastolic volume allows to maintain a normal ejection fraction in the presence of distinct heart failure.

Normalisation of diabetic heart pump function at decreased functional load.

Aim      To study left ventricular (LV) hemodynamics in presence of decreased blood inflow to the heart as well as changes in myocardial content of energy metabolites in diabetic rats.Material and methods  Diabetic cardiomyopathy is characterized by impaired heart contractility and by transition of cardiomyocyte energy metabolism fatty acids exclusively as a source of energy. This reduces the efficiency of energy utilization and increases the heart vulnerability to hypoxia. This study was performed on rats with type 1 diabetes mellitus induced by administration of streptozotocin (60 mg/kg). The LV pump function was studied with a catheter that allows simultaneous measurement of LV pressure and volume in each cardiac cycle.Results Blood glucose was approximately sixfold increased at 2 weeks. Heart failure was detected with decreases in ejection fraction by 27%, minute volume by 39%, and stroke work by 41%. Systolic dysfunction was based on a decrease in LV peak ejection velocity by more than 50%. Furthermore, the LV developed pressure and contractility index were within the normal range, while 1.5 times increased arterial stiffness was the factor that hampered ejection. The sum of adenine nucleotides was decreased by 21%, the ATP content was decreased by 29%, and also creatine phosphate formation was reduced in the myocardium of diabetic rats. Lactate content in the diabetic myocardium was increased almost threefold, which indicated mobilization of aerobic glycolysis. With the reduced preload, equal diastolic volume (0.3 ml), and equal blood pressure (60 mm Hg), the diabetic heart pump function did not differ from the control.Conclusion      In type 1 diabetes mellitus, decreases in functional load and oxygen consumption normalize the myocardial pump function with disturbed energy metabolism.

Compensatory Changes of the Diastole under Conditions of Inflow Restriction to the Heart.

This work was designed to study changes in the mechanical properties of rat myocardium during short-term (2-3 sec) compression of the lower vena cava. A catheter was inserted into the left ventricle, allowing simultaneous measurement of left-ventricular volume and pressure. The decrease in the left-ventricular end-diastolic volume caused by inflow restriction was accompanied by less pronounced decrease in the left-ventricular stroke volume and maximum rate of left-ventricular pressure development. This was coincided with accelerated relaxation and deeper fall of the minimum left-ventricular diastolic pressure. The lower was left-ventricular end-systolic volume, the greater was the degree of these changes. It is assumed that the "restoring force" that naturally appears under conditions of low filling of the left ventricle is determined by elastic N2B part of the titin molecule that is compressed during strong shortening of myofibrils and accelerates their return to the previous length during relaxation. As a result of better filling of the left ventricle, the heart can maintain left-ventricular stroke volume at the appropriate level.

Systolic Dysfunction of the Heart in Type 1 Diabetes Mellitus.

Impaired insulin synthesis is accompanied by hyperglycemia and the development of diabetic cardiomyopathy. Echocardiography and left-ventricular catheterization were employed for studying the contractile function of the left ventricle in 2 weeks after administration of streptozotocin (60 mg/kg). The results obtained by both methods were similar and indicated the development of systolic dysfunction with a 27% decrease in cardiac output. The invasive study showed that the maximum rate of left-ventricular pressure development, the contractility index, and systolic left-ventricular pressure were within the normal range, but the peak ejection rate was reduced by 28%. BP was normal, but the vascular stiffness index was increased by about 1.5 times and inversely correlated with the peak ejection rate (r=-0.69). The results showed that systolic dysfunction in type 1 diabetes model was due to reduced ejection from the left ventricle at normal rate of left-ventricular pressure development.

Study of Translocation of Stabilized NO Forms through Rat Skin using Electron Paramagnetic Resonance Method.

We studied the effect of dinitrosyl-iron complexes with N-acetyl-L-cysteine as a thiol-containing ligand (DNIC-Acc) after transdermal administration to rats. Electron paramagnetic resonance spectroscopy with a lipophilic NO spin trap (a complex of iron and diethyldithiocarbamate ions) showed that DNIC-Acc administration significantly increased the total level of NO in the lung and liver tissues of the animal, which was accompanied by a slight decrease in the mean BP (<10%).

Gaseous Nitric Oxide and Dinitrosyl Iron Complexes with Thiol-Containing Ligands as Potential Medicines that Can Relieve COVID-19.

It is shown that the inhalation of gaseous nitric oxide (gNO) or sprayed aqueous solutions of binuclear dinitrosyl iron complexes with glutathione or N-acetyl-L-cysteine by animals or humans provokes no perceptible hypotensive effects. Potentially, these procedures may be useful in COVID-19 treatment. The NO level in complexes with hemoglobin in blood decreases as the gNO concentration in the gas flow produced by the Plazon system increases from 100 to 2100 ppm, so that at 2000 ppm more than one-half of the gas can be incorporated into dinitrosyl complexes formed in tissues of the lungs and respiratory tract. Thus, the effect of gNO inhalation may be similar to that observed after administration of solutions of dinitrosyl iron complexes, namely, to the presence of dinitrosyl iron complexes with thiol-containing ligands in lung and airway tissues. With regard to the hypothesis posited earlier that these complexes can suppress coronavirus replication as donors of nitrosonium cations (Biophysics 65, 818, 2020), it is not inconceivable that administration of gNO or chemically synthesized dinitrosyl iron complexes with thiol-containing ligands may help treat COVID-19. In tests on the authors of this paper as volunteers, the tolerance concentration of gNO inhaled within 15 min was approximately 2000 ppm. In tests on rats that inhaled sprayed aqueous solutions of dinitrosyl iron complexes, their tolerance dose was approximately 0.4 mmol/kg body weight.

[Endovascular treatment of aneurysms and pseudoaneurysms of visceral arteries]. / Éndovaskuliarnoe lechenie anevrizm i psevdoanevrizm vistseral'nykh arterii.

AIM: The purpose of the study was to demonstrate the possibilities and efficacy of endovascular interventions in patients with visceral artery aneurysms. PATIENTS AND METHODS: From 2013 to June 2020, we performed 15 embolizations of visceral artery aneurysms in 15 patients (8 men and 7 women). The technical success rate was 100%. The patients' age varied from 32 to 71 years. In 8 cases, the aneurysm was located in the basin of the splenic artery, in 3 cases in the gastroduodenal artery, in 2 cases in the superior mesenteric artery and in 2 cases in the renal artery. Three aneurysms were classified as false, and 12 as true. All aneurysms were saccular, with their diameter ranging from 6 to 32 mm. In 2 patients aneurysms were detected after endured infective endocarditis, in 8 during examination in abdominal pain syndrome, and in 5 cases as an incidental finding while performing computed tomography of abdominal organs. One patient was subjected to embolization of the afferent vessel, two underwent implantation of stent grafts into the aneurysmal neck area, and eleven underwent aneurysmal sac embolization with microcoils. In 9 cases, embolization was performed using microcoils only in 1 case using microcoils with balloon assistance, and in 2 cases using microcoils with stent assistance. We used from 1 to 12 microcoils, with a diameter of from 2 to 30 mm. RESULTS: During endovascular embolization of visceral artery aneurysms there were no target-organ infarctions, haemorrhagic complications, nor lethal outcomes. In the early postoperative period, 7 patients developed pain syndrome. In 1 case pain syndrome was relieved by narcotic analgesics, in 4 cases by spasmolytics, and in 2 cases by a combination of spasmolytics and non-narcotic analgesics. CONCLUSION: Endovascular treatment of visceral arterial aneurysms is an efficient and safe method.

[ORGANIZATIONAL AND METHODICAL PROBLEMS OF DISTANCE LEARNING OF MEDICAL STUDENTS IN THE COVID-19 PANDEMIC].

In connection with the COVID-19 pandemic, since March 2020, medical universities in different countries have been forced to switch to distance or blended learning formats. The article discusses the limitations and advantages of distance learning through a meta-analysis of the research results and the authors' own experience. The article describes different options for conducting current classes, intermediate and final online certification, the peculiarities of establishing new methods of communication and changes in student-teacher communication. Practical recommendations are offered for solving organizational, methodical, educational, technical and informational problems of RUDN University and A. I. Yevdokimov MSMSU, associated with distance learning of future doctors.

[The double diseases burdens trends in Ethiopia: COVID-19 aggravate the burdens of diseases and health system].

The relevance of the study included that scarcity of evidence about the burdens of diseases in Ethiopia, in particular to non-communicable diseases along with the impact of COVID-19. MATERIALS AND METHODS: The systematic analysis and content analysis using GBD 2019 database and health metrics datasets of 2020 was used to analyze diseases burdens trends of Ethiopia. The descriptive retrospective analysis has been performed, and reported in text and charts method. RESULTS: The result of the study showed increment of crude death and premature death due to both communicable and non-communicable diseases such as enteric infections, cardiovascular, neoplasm, others. CONCLUSION: COVID-19 would be the headache of Ethiopia health systems due to double burdens of diseases have steadily been shooting at ground. Hence, the nation should incite local based innovation work proactively and integrate all health services to fight with COVID-19 based on the experience of Russia.

[The development of prototype of "ideal" model of competences of executive manager in health care].

The formation of a prototype of the organizational functional model of competences of the "ideal" health care manager and availability of objective assessment of its activities are of considerable practical interest. In any medical organization there is a need for trained, experienced and motivated administrators - managers capable effectively achieve their goals. This need can be met by developing and improving managerial competencies in managers at all levels. The competences of manager can be developed on the basis of organizational functional model and in accordance with personal responsibilities, work status, goals of medical organizations and professional standard. THE PURPOSE OF THE STUDY: was to develop a prototype of "ideal" organizational functional model of competencies of administrator - health care manager. MATERIALS AND METHODS: On the basis of data content analysis, evaluation of experimental results and logical and comparative technique a prototype of the "ideal" organizational functional model of health care manager was developed and tested. The development of model of administrators competences was based on comparative parameters of the professional standard "The specialist of health care and public health," personal managership of administrators of medical organizations, in accordance with the work status and objectives proposed in the course of the study organized in the Chelyabinsk Regional Children's Clinical Hospital (n = 26). THE RESULTS: The analysis of the factors affecting quality of management functions performed by managers, presented in t professional publications and based on the results of competence model testing, permitted to conclude that the requirements of the professional standard "The specialist of Health Organization and Public Health" are not sufficient to completely assess the activities of administrator - manager. To improve comprehensiveness of assessment of managers and the development of "ideal" model of executive manager competence the listing of requirements in the professional standard is to be supplemented with "The necessity of satisfaction with own work", "The necessity of conscious motivation to work at managerial position", "The necessity of abilities to perform management activities".

[Prevention of Diastolic Dysfunction Caused by Doxorubicin by Mitochondrial Antioxidant Plastomitin].

Aim      An attempt to prevent the development of diastolic dysfunction (DD) with the mitochondrial antioxidant plastomitin on a model of doxorubicin-induced cardiomyopathy. DD is a type of chronic heart failure. Due to the increasing number of patients with this condition and the absence of effective therapy, development of means for DD correction is a relevant objective.Material and methods  Cardiomyopathy was modeled in 17 rats by two subcutaneous injections of doxorubicin 2 mg/kg/week. The other group (n=17), also administered with doxorubicin, received plastomicin 0.32 mg/kg daily subcutaneously. Left ventricular function was evaluated with echocardiography (EchoCG) and cardiac catheterization with simultaneous pressure and volume monitoring.Results According to EchoCG data the ejection fraction remained unchanged in the experimental groups. Cardiac catheterization showed disorders of both myocardial contractility and relaxability only in the doxorubicin group.Conclusion      A course of plastomitin in combination with the doxorubicin treatment can maintain normal heart contractility and thereby, prevent the known doxorubicin cardiotoxicity.