A comparative study of the volume-speed parameters of the human external respiration system was carried out under the influence of an additional weight load: a body armor weighing 11 kg and a backpack weighing 15 kg. The nature of changes in the main spirometric parameters under the influence of an added mass is typical for restrictive disorders of pulmonary function. A marked decrease in forced vital capacity (FVC) and forced expiratory volume in 1 s (FEV1) values was observed when performing the test with a protective vest. In the conditions of a combination of body armor and a backpack, these changes were more pronounced (p < 0.01). At the same time, there were no significant changes in the Tiffno index values (FEV1/FVC). In addition, a significant decrease in the values of maximum voluntary ventilation (MVV) was revealed by 8.1

In the review, a generalized analysis of current scientific data explaining the physiological mechanisms of the influence of obesity on respiratory system is carried out. The multifactorial nature of the respiratory effect of obesity, including mechanical and inflammatory effects, is emphasized. The consequences of restrictive and obstructive changes in the biomechanics of respiration, changes in the topographic distribution of lung ventilation, mismatch of ventilation and perfusion, and a decrease in the efficiency of the respiratory muscles are considered. Elucidation of the central mechanisms of the respiratory action of proinflammatory mediators expressed by adipose tissue cells is recognized as a promising area of research. Special attention is paid to the action of leptin, which is the main regulator of metabolism and respiratory control in obesity. Its ability to modulate the central respiratory chemosensitive is discussed. It is assumed that an increase in pulmonary ventilation due to an increase in leptin production in obesity has a compensatory character and allows obese patients to maintain normocapnia despite an increase in mechanical load on respiration system. Whereas leptin resistance and suppressed hypercapnic ventilation response play a key role in the development of obesity–hypoventilation syndrome. It is concluded that it is necessary to further study the physiological mechanisms of the influence of obesity on the respiratory function in order to find new effective therapeutic methods for the treatment of diseases associated with obesity, which is the main factor in the development of metabolic syndrome.

A pressing issue of the day is the identification of therapeutic targets to suppress the "cytokine storm" in COVID-19 complicated by acute respiratory distress syndrome (ARDS) with concomitant hypoxemia. However, the key cytokine and its relative contribution to the pathogenesis of ARDS, which leads to high mortality, are unknown. A comparative assessment of the effect of elevated systemic levels of pro-inflammatory cytokines IL-1β, TNF-1α and IL-6 on the respiratory patterns and survival rate in rats was carried out under progressively increasing acute hypoxia. Increasing hypoxia was simulated by a rebreathing method (from normoxia to apnea). The recorded parameters were the breathing pattern components (tidal volume and respiratory rate), minute ventilation (MV), oxygen saturation, apnea onset time, and posthypoxic survival rate. A comparative analysis was carried out under mild, moderate and severe hypoxia (at FIO2 = 15, 12 and 8%, respectively). It was shown that increasing hypoxia was accompanied by an acute suppression of the compensatory elevation of MV in rats with increased systemic levels of IL-1β and TNF-1α. By contrast, IL-6 caused an intensive elevation of MV with increasing hypoxia. Acute hypoxia (FIO2 < 8%), in all experimental series, was accompanied by an impairment of the respiratory rhythm up to the development of apnea. Posthypoxic breathing restoration (survival rate) was 50% with IL-1β and TNF-1α and only 10% with IL-6. The obtained results indicate that the elevated IL-6 level, despite the absence of respiratory disorders at the initial stage of the developing pathologic process, leads to a higher mortality in rats compared to IL-1β and TNF-1α. This allows considering IL-6 as an early prognostic biomarker of a high risk of mortality under severe hypoxemia.

Ventilatory function variables and maximum inspiratory pressure (MIP) and expiratory pressure (MEP) were studied in athletes training strength and endurance. 36 athletes engaged in swimming (n = 12), game sports (n = 12) and wrestling (n = 12); in addition, 14 age-matched and sex-matched sedentary controls were examined. The observed values of MIP and MEP as well as the dynamic ventilatory variables in swimmers were significantly higher than those in control subjects and wrestlers. A close correlation was shown between MIP/MEP and the maximum voluntary ventilation both in the control group (r = 0.86 and r = 0.81 for MIP and MEP, respectively (p < 0.01)) and in the group of wrestlers (r = 0.87 (p < 0.01) and r = 0.66 (p < 0.05)). A weak relationship was found in the group of game players; in the group of swimmers, this relationship was completely nonsignificant. These data allow us to conclude that dynamic exercises in athletes who train endurance and static exercises in athletes who train strength cause different adaptive changes in the ventilatory function. Most of changes and an increase in functional reserves in the respiratory system are observed in athletes who train endurance, especially swimmers. Minimum changes are observed in athletes engaged in different types of wrestling. In this regard, the effectiveness of specific training of the respiratory muscles will be higher in athletes of power and game sports in comparison with athletes engaged in swimming.

At the present time very little is known about interactions between systemic inflammation and control of respiration. The aim of this study was to compare the respiratory effects of the main inflammatory cytokine TNF - α before and after pretreatment with diclofenac, a nonspecific cyclooxygenase (COX) inhibitor. In experiments on anesthetized, tracheostomized rats, pneumotachometry method was used to measure peak airflow and respiratory rate. The ventilatory response to hypoxia was investigated by the rebreathing method. It is shown that an increase in the systemic level of TNF – α causes a significant increase in the minute volume of respiration, tidal volume, the average speed of the inspiratory flow. In contrast the slope of the hypoxic ventilatory response decreased after administration of TNF-α. Diclofenac pretreatment eliminated these respiratory effects of TNF - α. The data indicate that the ability of TNF - α to enhance basal ventilation and to reduce the ventilatory hypoxic response is mediated by the cyclooxygenase pathway. Key words: tumor necrosis factor – α, hypoxia, prostaglandins, peripheral chemoreception, respiration.

Interleukin-1β (IL-1β) and tumor necrosis factor-α (TNF-α) are the major proinflammatory cytokines. Cytokine receptors are expressed in the brainstem areas involved in respiratory control, as well as in the carotid bodies that control the O 2 balance in arterial blood. We hypothesized that circulating proinflammatory cytokines are able to affect lung ventilation and modulate the respiratory response to hypoxia by activating NO-dependent pathways. The aim of our study was to compare the respiratory effects of IL-1β and TNF-α before and after pretreatment with L-NAME, a non-selective inhibitor of NO synthase (NOS). The ventilatory response to hypoxia was measured in anesthetized Wistar rats using the rebreathing method before and after intravenous administration of IL-1β (2 µg/kg) and TNF-α (40 µg/kg). It was found that an increase in the systemic level of proinflammatory cytokines increases lung ventilation under normoxia, while reducing respiratory sensitivity to hypoxia. Pretreatment with L-NAME (intraperitoneal administration) reduced these respiratory effects of both IL-1β and TNF-α. We believe that the activation of NOS pathways and an increase in NO synthesis, when cytokines interact with the corresponding receptors, mediate the respiratory effects of proinflammatory cytokines and underlies the effect of inflammation on respiratory function.

We studied the effect of increased systemic levels of the proinflammatory cytokine IL-1β on the vasomotor reactions of pial microvessels in anesthetized rats under conditions of experimentally simulated progressively increasing acute normobaric hypoxia. Vital microscopy showed that more pronounced dilatation of pial vessels in response to IL-1β under hypoxic conditions was almost completely prevented by pretreatment with non-specific NO synthase blocker L-NAME. These findings indicate the involvement of NO-dependent mechanisms in the vasodilator effect of proinflammatory cytokines under conditions of acute hypoxic exposure.

Введение. Снижение работоспособности и ортоустойчивости, наблюдаемых у космонавтов на разных этапах космического полета, диктует необходимость поиска новых методов, способствующих улучшению переносимости экстремальных факторов и восстановлению нарушенных функций организма, в реабилитационном периоде. Одним из перспективных направлений, повышающих общую неспецифическую резистентность организма являются гипоксические тренировки. Вместе с тем сведения о применении гипоксического воздействия непосредственно в условиях космического полета для нивелирования неблагоприятных эффектов невесомости отсутствует. Цель исследования - изучение влияния нормобарической периодической гипоксии на кардиореспираторные показатели и резервные возможности организма крыс при свободном двигательном режиме и в условиях антиортостатической гипокинезии (антиортостатическое вывешивание с углом наклона -30°), моделирующей физиологические эффекты невесомости. Методика. Проведено 4 серии экспериментов на 48 крысах Вистар, массой 280-300 г. Животные в течение 7 сут находились: в 1-й серии в свободном двигательном режиме с ежедневной 5-часовой нормобарической гипоксией (12% О2); во 2-й - в условиях антиортостатической гипокинезии после предварительного курса гипоксии; в 3-й - в антиортостатической гипокинезии без предварительной гипоксии (нормоксия 20,9% О2); в 4-й - в антиортостатической гипокинезии с ежедневной 5-часовой гипоксией. После завершения эксперимента у всех животных регистрировали кардиореспираторные показатели методом пневмотахографии, электрокардиографии, пульсоксиметрии, для оценки физической выносливости крыс использовали тест вынужденного плавания (по Порсолту). Результаты. Установлено, что эффективность НПГ в целях повышения функциональных резервов кардиореспираторной системы после длительного пребывания в условиях антиортостатической гипокинезии достигается только в результате предварительной адаптации (прекондиционирования) к периодической гипоксии в свободном двигательном режиме. Заключение. Воздействие нормобарической периодической гипоксии в условиях моделирования невесомости приводит к ухудшению функционального состояния организма и снижению физической выносливости крыс.Introduction. Restoring the physical condition of cosmonauts following a prolonged spaceflight requires new methods for improvement of resistance to extreme factors and recovery during the rehabilitation period. A promising approach to enhancing the general, nonspecific resistance to adverse environmental factors is hypoxic training. However, information about the use of hypoxia effects on the scene of a space flight to neutralize adverse effects of weightlessness is absent. Aim. To study the effect of intermittent normobaric hypoxia (INH) on cardiorespiratory parameters and reserve capacity of rats in free locomotion and in head-down tilt of -30°(HDT-30° ), a model of spaceflight. Methods. Experiments were performed on 48 Wistar rats weighing 280-300 g. For 7 days the animals were 1) in free locomotion with INH daily for 5-hours (12% O2); 2) in HDT-30o under normoxia following prior INH; 3) in HDT-30° under normoxia; 4) in HDT-30° in combination with INH. Cardiorespiratory parameters were recorded by pneumotachography, electrocardiography and pulse oximetry. Exercise tolerance was evaluated using the forced swimming test (Porsolt). Results. The effect of INH in increasing the cardiorespiratory functional reserve after long-term simulated microgravity is achieved only with prior adaptation (preconditioning) to INH in free locomotion. Conclusions. Intermittent normobaric hypoxia used in simulated microgravity leads to impairment of the functional state and decreases physical endurance of rats.

Abstract—The task of this review was to acquaint specialists with the methodical aspects of studies devoted to the function of human respiratory muscles and the most important points in the interpretation of investigation results. The paper discusses specialized aspects in measuring the maximal respiratory pressures, the main principles of the electromyographic techniques, as well as a possible application of the tension–time index calculation in its various modifications to the assessment of the functional state of inspiratory muscles and the determination of their reserve potential in the norm and diseases that generate additional loads on the respiratory muscles. The functional assessment of respiratory muscles is significant for differential diagnostics in some diseases of the bronchopulmonary, neuromuscular, and cardiovascular systems. The analysis of the functional potential contained in the motor apparatus of the external respiratory system may prove to be very useful for specialists in experimental physiology and athletic and rehabilitation medicine.

The article presents the results of application of photochemotherapy in the complex rehabilitation process of patients with bronchial asthma (hereinafter — BA). The assessment of effectiveness and impact was made on the basis of changes in indicators of blood rheology as one of the pathogenesis of this disease and based on clinical indicators of the flow BA.It is established that in comparison with the results of the baseline treatment (42 patients) in 74 patients with BA under the influence of photochemotherapy occurs a statistically significant restoration of the altered rheological parameters and improves the clinical course of BA. The effect of optical radiation of blue and red lights on the clinical course of BA in comparison with conventional medication is more pronounced, almost the same criteria of treatment efficacy, but differ in their mechanism of effects on the body.

The purpose of the study is to identify the role of nitrergic mechanisms in the ability of the pro-inflammatory cytokine IL-1β to influence the respiration pattern and hypoxic ventilation response. Materials and Methods. The experiments were performed on 42 anesthetized rats. To conduct an inhibitory analysis of the nitric oxide role in the manifestation of IL-1β respiratory effects, the authors used a non-selective inhibitor of NO-synthases of Nitro-L-arginine-methyl ether (L-NAME), and a highly specific inhibitor of inducible nitric oxide synthase, aminoguanidine bicarbonate. The hypoxic ventilation response was evaluated by a rebreathing method with a hypoxic gas mixture before and after intravenous administration of human recombinant IL-1β. Pneumatic tachometry was used to register the parameters of external respiration. Results. Intravenous administration of IL-1β has an activating effect on respiration and causes an increase in tidal volume by 36±5.2 %, minute respiration volume by 23±3.8 % and average inspiratory flow rate by 20±3.0 %. However, an increase in IL-1β systemic level decreases the ventilation response to hypoxia. Inhibition of NO-synthase activity with both L-NAME and aminoguanidine reduces IL-1β respiratory effects. Conclusion. One of the mechanisms to implement the respiratory effects of the key pro-inflammatory cytokine IL-1β in case of increase in its circulating level is an increase in the synthesis of nitric oxide with vascular endothelium cells. Keywords: cytokines, interleukin-1β, ventilation, ventilation response to hypoxia, hypoxic chemoreflex, nitric oxide. Цель исследования. Выявление роли нитрергических механизмов в способности провоспалительного цитокина ИЛ-1β оказывать влияние на паттерн дыхания и гипоксический вентиляционный ответ. Материалы и методы. Эксперименты выполнены на 42 наркотизированных крысах. Для проведения ингибиторного анализа роли оксида азота в проявлении респираторных эффектов ИЛ-1β использовались неселективный ингибитор NO-синтаз L-нитро-аргинин-метилэфира (L-NAME), а также высокоспецифичный ингибитор индуцибельной синтазы оксида азота аминогуанидина бикарбоната. Гипоксический вентиляционный ответ оценивался методом возвратного дыхания гипоксической газовой смесью до и после внутривенного введения человеческого рекомбинантного ИЛ-1β. Для регистрации параметров внешнего дыхания использовался метод пневмотахометрии. Результаты. Показано, что внутривенное введение ИЛ-1β оказывает активирующее влияние на дыхание, вызывая увеличение дыхательного объема на 36,0±5,2 %, минутного объема дыхания – на 23,0±3,8 % и средней скорости инспираторного потока – на 20,0±3,0 %. Вместе с тем повышение системного уровня ИЛ-1β вызывает ослабление вентиляционного ответа на гипоксию. Ингибирование NO-синтазной активности с помощью как L-NAME, так и аминогуанидина ослабляет респираторные эффекты ИЛ-1β. Выводы. Одним из механизмов реализации респираторных эффектов ключевого провоспалительного цитокина ИЛ-1β при повышении его циркулирующего уровня является усиление синтеза оксида азота клетками сосудистого эндотелия. Ключевые слова: цитокины, интерлейкин-1β, вентиляция, вентиляционный ответ на гипоксию, гипоксический хеморефлекс, оксид азота.

INTRODUCTION:Myocarditis is one of the most urgent and in many respects unresolved problems in cardiology. The situation is further aggravated by the ever increasing incidence of the of disease. The lack of knowledge about myocarditis etiology and pathogenesis creates a number of difficulties for the choice of the adequate treatment strategies.AIM:The objective of the present study was to evaluate the effectiveness of quantum photohemotherapy (PHT) with the use of a blue light in the combined treatment of infectious-allergic myocarditis (IAM).MATERIAL AND METHODS:We examined a total of 28 patients including 12 women and 16 men at the age from 16 to 45 years suffering from IAM. The diagnosis of IAM was confirmed clinically, biochemically, and functionally with the application of the blood tests, chest X-ray examination, echo- and electro-cardiography. We used the classification of N.R. Paleev and M.A. Gurevich for myocarditis diagnostics. The diagnosis of ischemic heart disease was excluded according to the WHO criteria. The degree of heart failure in the patients was assessed based on the NYHA classification criteria. All the patients were given therapy with nonsteroidal anti-inflammatory drugs, metabolic drugs, anti-arrhythmics, diuretics, and angiotensin converting enzyme inhibitors. In addition, the generally accepted methods for the characteristic of blood rheological properties were employed. Moreover, the universally recognized rehabilitative and therapeutic measures were supplemented by blue light PHT using an AFS-Solaris light-emitting diode for intravascular irradiation of blood through the disposable light guides.RESULTS:The study has demonstrated that IAM was accompanied by a number of hemorheological disorders that collectively make up a component of pathogenesis of the condition in question. The application of blue light PHT for the combined treatment of the patients with IAM led to the improvement in their rheological status and peripheral blood characteristics.CONCLUSION:Various hemorheological disorders were diagnosed in the patients suffering from infectious-allergic myocarditis. The main effect of blood viscosity reduction documented in the patients with IAM under the influence of blue light PHT was attributable to the reduction in hematocrit decreasing and suppression of the erythrocytes aggregation activity.

The results of this study confirm that the Elevation Training Mask 2.0 (ETM) increases the physiological characteristics and functional reserve capacity of the respiratory muscles. This is manifested in an increase in the maximal strength of muscle contraction, significantly greater maximal voluntary ventilation, an increase in the endurance and resistance of inspiratory and expiratory muscles to the development of fatigue when performing heavy exercise. An adequate indicator of the functional status of inspiratory muscles for the assessment of their functional potential is the tension–time index, ТТ0.1.