Sleep deprivation is widespread in modern society as a consequence of chronic stress and specificity of a number of civilian and military specialties. Correction of its consequences should take into account the fundamental principle of unity of form and function, realized by cellular-glial ensembles of anatomical formations of the brain. In this connection, the aim was set to characterize microscopic and ultramicroscopic rearrangements of brain structures involved in the regulation of the sleep–wake cycle during sleep deprivation. Changes in the main structures providing alternation of sleep–wake cycles acquire a pathological nature only in conditions of prolonged sleep deprivation associated with a threat to life. As a consequence, the methods of light microscopy are not sensitive enough to reveal the developed changes; however, electron microscopic study allows us to identify both specific ultramicroscopic rearrangements and desynchronosis between quantitative characteristics of organelles of cells of neuroglial ensembles and brain structures functionally united in providing the sleep–wake cycle.

Electrocorticography in rats has broad indications for use in biomedical research. This is due to the high translational potential from rodents to humans, established by comparative experimental electrocorticography under the action of a wide range of neurotropic substances. The paper presents the features and technique of manufacturing an electrocorticographic sensor, as well as the technique of its implantation in rats. The sensor was experimentally tested according to the validity of the received signal under the conditions of administration of neurotropic pharmacological probes: strychnine, corazole, sodium cyanide, tiletamine with zolazepam, xylazine, dexmedetomedin and diisopropylphenol. According to ethological and pathomorphological criteria, the tolerability of the structure in the skull by rats was assessed. It has been established that the design of the sensor and the technique of its implantation in rats are safe and effective for long-term monitoring in conditions of free movement. The correspondence of the received data to the expected ones and the high quality of the signal-to-noise ratio make it possible to consider the signal from the sensor as valid and diagnostically valuable. The design is well tolerated by rats and does not cause pronounced changes in the histomorphological picture of the brain in the area of electrode attachment to the cortex for 90 days after implantation.

Military toxicology teaching specialists of higher education military institution, in line with special professional development programs, have considered issues of emerging discipline allowing for the forms of knowledge transmission, as part of the joint scientific research and organized postgraduate education courses. Paper studies the organizational approaches to the lecture course design in terms of higher professional education. Forms of military toxicology teaching were systematized using simulants of toxic substances, fundamental knowledge of the critical processes’ physiology, their pharmacological and pharmaceutical modifications, molecular docking in risk evaluation of new toxicants creating.

Актуальность. Ведущую роль в патогенезе коронавирусной инфекции, вызванной SARS-CoV-2 (COVID-19), играют гиперкоагуляционные сдвиги в системе гемостаза, изменение функционального состояния эндотелия и системная дисфункция микроциркуляции. Принимая во внимание риск цереброваскулярных осложнений COVID-19 в острый период, а также при постковидном синдроме, особую важность приобретают исследования ультраструктурных изменений сосудов головного мозга для расширения знаний о патогенезе COVID-19-ассоциированной эндотелиопатии и разработки подходов к её фармакологической коррекции. Морфологическим эквивалентом изучения секреторной активности эндотелия сосудов может выступать кинетика структуры телец Вейбеля-Паладе, уникальных для эндотелиоцитов органелл, экзоцитоз которых определяет условия тромбообразования. Цель – электронно-микроскопическое исследование кинетики структуры телец Вейбеля-Паладе в эндотелии сосудов неокортекса сирийских хомяков в динамике инфекции SARS-CoV-2. Материалы и методы. Экспериментальную модель воспроизводили посредством интраназального введения сирийским хомякам культуры вируса, содержащей SARS-CoV-2 в количестве 4 × 104 ТЦД50/мл. На 3-и, 7-е, 14-е и 28-е сутки после заражения выполняли эвтаназию животных с последующим отбором образцов ткани неокортекса. Исследование материала проводили методом трансмиссионной электронной микроскопии. Результаты. Прослежена кинетика накопления и высвобождения секрета телец Вейбеля-Паладе в эндотелии сосудов неокортекса сирийских хомяков на экспериментальной модели SARS-CoV-2 инфекции. Выявлено увеличение секреторной активности эндотелиоцитов сосудов неокортекса у животных в период 3-7 суток после заражения в виде экзоцитоза телец Вейбеля-Паладе. Выявленные ультраструктурные изменения эндотелия у экспериментальных животных прослежены до 28 суток инфекционного процесса. Заключение. Результаты электронно-микроскопического исследования секреторной активности эндотелия сосудов неокортекса сирийских хомяков в динамике инфекции SARS-CoV-2 позволили определить риски сосудистых катастроф как в остром, так и в реконвалесцентном (28 суток) периоде заболевания. Полученные результаты значимы для расширения знаний о патогенезе эндотелиальной дисфункции, определяющей вероятность цереброваскулярных осложнений в критические периоды COVID-19, что представляет особую важность при проведении исследований, направленных на разработку и изучение новых средств терапии данной патологии. Background. Hypercoagulation, changes in the functional state of endothelium and systemic microcirculation dysfunction play a leading role in the pathogenesis of coronavirus infection caused by SARS-CoV-2 (COVID-19). Taking into account the risk of cerebrovascular complications of COVID-19 in the acute period, as well as in post-COVID-19 syndrome, studies of ultrastructural changes in cerebral vessels are of particular importance for expanding knowledge about the pathogenesis of COVID-19- associated endothelial pathology and developing approaches to its pharmacological correction. The morphological equivalent of studying the vascular endothelium secretory activity can be the structural kinetics of Weibel-Palade bodies, organelles unique to endotheliocytes, the exocytosis of which determines the conditions of thrombosis. The aim is to electron microscopic study the kinetics of Weibel–Palade body’s structure in the endothelium of the neocortex vessels of Syrian hamsters in the dynamics of SARS-CoV-2 infection. Materials and methods. The experimental model was reproduced by intranasal administration to Syrian hamsters of a virus culture containing SARS-CoV-2 in an amount of 4 × 104 TCD50/ml. On days 3, 7, 14 and 28 after infection animals were euthanized with subsequent selection of neocortex tissue. The study of the material was carried out by transmission electron microscopy. Results. The kinetics of accumulation and release of the secretion of Weibel-Palade bodies in the endothelium of the neocortex vessels of Syrian hamsters on an experimental model of SARS-CoV-2 infection was traced. It was found that secretory activity of neocortical vascular endotheliocytes in animals increases in the period 3–7 days after infection in the form of exocytosis of Weibel-Palade bodies. The revealed ultrastructural changes of the endothelium in experimental animals persist up to 28 days of the infectious process. Conclusion. The results of electron microscopic examination of the neocortex vessels endothelium secretory activity of Syrian hamsters in the dynamics of SARS-CoV-2 infection allowed us to determine the risks of vascular catastrophes both in the acute and convalescent (28 days) periods of disease. The results obtained are significant for expanding knowledge about the pathogenesis of endothelial dysfunction, which determines the likelihood of cerebrovascular complications during critical periods of COVID-19, which is of particular importance when conducting research aimed at developing and studying new therapies for this pathology.

Introduction. Taking into account the experience on the new coronavirus infection COVID-19 pandemic, the relevance of studies assessing the cellular processes of SARS-CoV-2 virus assembly and transport to justify the choice of pharmacological action points has now markedly increased. The study was aimed at analyzing morphologically assessed events of SARS-CoV-2 life cycle in neocortical neurons using electron microscopy based on its traced wide prevalence in vivo and ability to penetrate the blood-brain barrier accounts. Materials and methods. Patient-derived SARS-CoV-2 virus was obtained and accumulated in Vero(B) cell culture. An electron microscopy study (EMR) of the viral particle transport was carried out in male Syrian hamsters. Animals were inoculated intranasally with 26 mu l of virus culture in an amount of 4 x 104 TCID50/ml. Animals were euthanized on day 3, 7, and 28 post-infection. The extracted brain was prepared for EMR according to methods previously described in the literature. The results were recorded using an FEI Tecnai G2 Spitit BioTWIN electron microscope. Results. Using EMR, the morphological equivalents of virus transport variants in neocortical neurons were traced dynamically during infectious process in Syrian hamsters. After synthesis, viral membrane proteins are included in transport vesicles in the endoplasmic reticulum (ER) terminal tubules and enter the intermediate compartment (IC), a collection of smooth-walled membrane vesicles between the endoplasmic reticulum (ER) and the Golgi apparatus (AG). In the first 3 days post-infection, viral copies are included in the Ag in PC membrane-formed transport vesicles. Due to the large size, viral particles are restricted to the expanded ends of the mobile AG tanks. Morphologically, destruction of AG membranes was revealed on day 7 post-infection, which indicates an interaction between PC vesicles and preserved AG membrane elements or the implementation of their independent transport func-tion to deliver SARS-CoV-2 virus to the cell periphery and further into the intercellular space. In the neuronal processes, the transport of mature SARS-CoV-2 viral particles associated with cytoskeletal elements was observed, which was not detected in other loci of virus persistence. Conclusion. Based on data obtained, it is possible to hypothesize about a cu-mulative importance for progression and persistence of SARS-CoV-2 infection in cortical neurons. Early signs of neuron infection are represented by characteristic changes in the nuclei, ER hypertrophy and formation of "viral factories" based on the ER, PC and AG. The formation of viral biomass occurs inside neurons; virion exit from target cells is more accom-panied by cell death rather than if a virus becomes incorporated in the lysosomal-endosomal system.

INTRODUCTION. In the current practice of preclinical safety studies of pharmacologically active substances, standard neurotoxicity assessment procedures are mainly aimed at diagnosing higher nervous activity and behavioural disorders. However, it is the structures of the peripheral nervous system that are particularly susceptible to drug-induced neurotoxicity, which renders these structures an easy target and leads to a high incidence of neurotoxic side effects. These circumstances dictate the importance of refining methodological approaches to the assessment of toxic injury in the peripheral nervous system.AIM. The study aimed to analyse the current methodological level of clinical and functional tests for assessing the toxic effects of pharmacologically active substances on the structures of the peripheral nervous system, as well as to formulate practical recommendations for using these tests in preclinical studies in rodents.DISCUSSION. Rodents are considered the optimal test system for preclinical studies of pharmacologically active substances, but it is impossible to reproduce the entire neurological examination that is conducted to identify clinical equivalents of neurotoxicity in humans using these animals. This article presents a systematic approach to using available diagnostic tests to increase the translatability of data. The article briefly describes the neurological deficits due to adverse drug reactions in humans, as well as the main toxidromes that can also occur in animals. Based on a literature review and experience, the authors provide practical recommendations for performing basic tests to study the strength and tone of muscles, the state of physiological reflexes, the coordination of movements, and various types of sensitivities in rodents. The article provides a brief overview of the diagnostic utility of electrophysiological testing for identifying toxic damage to the peripheral nervous system. The following tests are recommended as a minimum list of primary screening techniques for detecting neurotoxic side effects in study animals: a resting posture assessment, the beam walking test, the horizontal bar test, the digit abduction score assay, the tail flick test, and the Preyer reflex test.CONCLUSIONS. The results of a comprehensive assessment of neurological deficits in rodent experiments should be analysed from a clinically relevant perspective— that is, with a focus on topical diagnosis and common pathological process components. It is advisable to verify the pathological process at the level of the peripheral nervous system using a set of electrophysiological techniques.

A study of structural changes in lung tissue during the formation of organ edema due to inhalation of a lipotropic poison, carbonic acid dichloride, showed the peculiarities of the formation of acute respiratory distress syndrome. The point of application of the poison is the distal bronchioles, whose epithelium is subject to dystrophic and necrotic changes followed by goblet metaplasia. The absorbed poison causes pronounced changes in blood microcirculation, steroid-resistant NO-mediated endothelial dysfunction with blood deposition in dilated capillaries, aggregation, and lysis of erythrocytes. Changes in the vascular bed in the interalveolar septa precede the formation of an acute inflammatory reaction with the accumulation of alveolar effusion and dystrophic changes in the alveolar epithelium with cell desquamation. Among the cells of the alveolar lining, type II alveolocytes are the most vulnerable. Plasma permeation of the connective tissue of the interalveolar septa interstitium is accompanied by their infiltration with polymorphonuclear leukocytes and activation of macrophages. Desquamation of epithelial cells of the distal bronchioles leads to obstruction of their lumens and, through the valve mechanism, contributes to overextension of the alveoli with the formation of emphysema and reduction of capillary blood circulation in the alveolar septa. The observed changes determined the directions for improving the treatment of poisoning by asphyxiating poisons.

The peculiarities of the influence of cytokines and metabolites of the systemic inflammatory reaction and stress-implementing and nutritional factors contributing to the transformation of the phenotype of the resident intestinal microflora with an increase in its virulence are described. From the perspective of expression of genes and conformations of proteins and phospholipids, the influence of temperature as a signaling factor in increasing the virulence of the intestinal microbiome is considered. Evolutionarily formed mechanisms of expression of the maximum pathogenic phenotype of microorganisms and, thus, achieving an increase in their biomass and maximum dissemination through the microorganism compartments increase the probability of the transmission of commensals to another biotope, i.e., increases the probability of their survival after the death of the host organism. To prevent bacterial translocation after the relief of critical conditions, early enteral administration of β-glucans in food mixtures, iron excretion, and relief of inorganic phosphate deficiency, including by induction of alkaline phosphatase synthesis, are substantiated.

INTRODUCTION:Verification of histological changes in respiratory system using Syrian (golden) hamsters (Mesocricetus auratus) as experimental model is an important task for preclinical studies of drugs intended for prevention and treatment of the novel coronavirus infection COVID-19.The aim of this work was to study pathological changes of pulmonary tissue in SARS-CoV-2 (Coronaviridae: Coronavirinae: Betacoronavirus; Sarbecovirus) experimental infection in Syrian hamsters.MATERIAL AND METHODS:Male Syrian hamsters weighting 80-100 g were infected by intranasal administration of culture SARS-CoV-2 at dose 4 × 104 TCID50/ml (TCID is tissue culture infectious dose). Animals were euthanatized on 3, 7 and 14 days after infection, with gravimetric registration. The viral load in lungs was measured using the polymerase chain reaction (PCR). Right lung and trachea tissues were stained with hematoxylin-eosin and according to Mallory.RESULTS AND DISCUSSION:The highest viral replicative activity in lungs was determined 3 days after the infection. After 7 days, on a background of the decrease of the viral load in lungs, a pathologically significant increase of the organ's gravimetric parameters was observed. Within 3 to 14 days post-infection, the lung histologic pattern had been showing the development of inflammation with a succession of infiltrative-proliferative, edematousmacrophagal and fibroblastic changes. It was found that initial changes in respiratory epithelium can proceed without paranecrotic interstitial inflammation, while in the formation of multiple lung parenchyma lesions, damage to the epithelium of bronchioles and acinar ducts can be secondary. The appearance of epithelioid large-cell metaplastic epithelium, forming pseudoacinar structures, was noted as a pathomorphological feature specific to SARS-CoV-2 infection in Syrian hamsters.CONCLUSION:As a result of the study, the specific features of the pathology of the respiratory system in SARSCoV-2 infected Syrian hamsters were described. These findings are of practical importance as reference data that can be used for preclinical studies to assess the effectiveness of vaccines and potential drugs.

This paper continues the discussion of higher fungi toxins, here their toxic nitrogen-free organic compounds are considered. The challenges linked to their study and systematization are discussed. Modern concepts of toxic processes induced by toxic terphenyls, sesquiterpenes, triterpenes, trichothecenes, and oligoisoprenoids are analyzed. Some recently discovered cytotoxic compounds of a similar structure are presented. It is concluded that the systematic study of nitrogen-free toxins is in demand, and this area of research has still not been well investigated.

INTRODUCTION:Convalescent COVID-19 patients have various signs of central nervous system damage, including those directly associated with SARS-CoV-2. Hence, studies of SARS-COV-2 related morphological changes in neocortex are particularly relevant for understanding the mechanisms of their formation and development of approaches to preclinical evaluation of the effectiveness of antiviral drugs. The purpose of the research is a longitudinal study of the ultrastructural alterations in Syrian hamsters neocortex after experimental SARS-CoV-2 infection.MATERIALS AND METHODS:Male Syrian hamsters weighing 80100 g, aged 4 to 6 weeks, were infected with 26 l SARS-CoV-2 intranasally with 4104 TCD50/ml of viral particles. The animals were euthanized on days 3, 7 or 28 post-infection, the brain was extracted with the cortex excision. The material analysis was performed using transmission electron microscopy.RESULTS AND DISCUSSION:On day 3 post-infection, the number of moderately hyperchromic neurons in neocortex increased, while by the day 7 the number of apoptotic cells significantly increased. Simultaneously, an increased signs of neuronophagy and representation of atypical glia were observed. Increased number of altered oligodendrocytes was observed on day 28 post-infection. Viral invasion was accompanied by changes in neocortical cells since day 3 post-infection, such as transformation of their nucleus, the rough endoplasmic reticulum and the Golgi vesicles as well as microvascular spasm with perivascular edema.CONCLUSION:As a result of electron microscopic study, the ultrastructural alterations in neocortex were described in an experimental model of SARS-CoV-2 infection. The findings can be used to identify the mechanisms of infection pathogenesis and to search for the new directions in development of medicines.

We studied the content of aquaporin-5 (AQP5) and epithelial sodium channel (ENaC) in rat lungs during the development of toxic pulmonary edema (TPE) caused by intoxication with phosgene and perfluoroisobutylene (1.5 LC50). The lung body weight index (LBI) was calculated and histological examination of the lung tissues was performed. Localization and expression of AQP5 and ENaC were determined by immunohistochemistry. Intoxication led to a significant (p<0.05) increase in LBI and histological changes typical of TPE 1 and 3 h after the exposure. In 1 and 3 h after phosgene intoxication, the AQP5 and ENaC content significantly (p<0.05) increased in comparison with the control. Similar changes in the AQP5 and ENaC content were observed 1 and 3 h after exposure to perfluoroisobutylene. It was hypothesized that AQP5 plays an important role in the formation of TPE caused by intoxication with acylating pulmonotoxicants. An increase in the content of ENaC can be considered as a compensatory reaction of the body aimed at clearance of the alveolar fluid.

This review article provides data on the current state of the pathogenesis peculiarities of body and lung inflammation (pneumonia) under the influence of damaging factors of various nature: infectious agents, chemical toxicants, as well as incorporated radionuclides, etc. The peculiarities of inflammation itself, as a typical pathological process, are considered. Information on mediators that induce the so-called pro-resolving phase of inflammation manifestations is given. Approaches to the neuroimmune correction of non-specific inflammation are substantiated. Data on the following alternative approaches to the correction of nonspecific inflammation are summarized: factors of the coagulation system, modulators of the integrated stress response, and modulators of sigma-1 receptors. Based on the data presented, general directions for the treatment of nonspecific pneumonia are formulated, including reflexogenic and anti-inflammatory therapy in combination with multimodal drugs, as well as pro-resolving therapy in combination with drugs that prevent fibrosis.

В литературном обзоре приведены современные представления о патогенезе и подходах к патогенетической терапии острого респираторного дистресс-синдрома. Рассмотрены механизмы активации нейтрофилов в ранние стадии развития этого синдрома и вклад нейтрофильных внеклеточных ловушек в прогрессирование воспалительных процессов. Показана важность дестабилизации межклеточных контактов эндотелия сосудов и альвеолярного эпителия в инициации отёка лёгких, а также роль эпителиальных натриевых каналов и аквапоринов на этапе резорбции альвеолярной жидкости при переходе в пролиферативную стадию синдрома. Отмечен вклад липидных противовоспалительных медиаторов в механизмах разрешения воспаления. Проанализированы результаты опубликованных экспериментальных и клинических исследований, подчеркивающих актуальность поиска новых стратегий фармакологического воздействия на основные звенья патогенеза этого жизнеугрожающего состояния. Описаны современные возможности патогенетической терапии, направленной на снижение нейтрофил-опосредованного повреждения ткани лёгких, уменьшение проницаемости аэрогематического барьера, а также восстановление структурной целостности и нормального клеточного состава легочной ткани. This review presents current concepts on the pathogenesis and approaches to pathogenetic therapy of acute respiratory distress syndrome. The authors addressed mechanisms of early neutrophil activation and the contribution of neutrophil extracellular traps to the progression of inflammatory processes. The review focused on the importance of destabilizing endothelial and alveolar epithelial intercellular junctions for initiation of pulmonary edema, as well as on the role of epithelial sodium channels and aquaporins at the stage of alveolar fluid resorption during the proliferative stage of the syndrome. The contribution of lipid anti-inflammatory mediators to the mechanisms of inflammation resolution was emphasized. The article analyzed results of published experimental and clinical studies that stressed the relevance of searching for new strategies of pharmacological interference with major steps in the pathogenesis of this life-threatening condition. The current capabilities of pathogenetic therapy were described that are aimed at reducing the neutrophil-mediated damage of lung tissue, at decreasing the permeability of the air-blood barrier, and at restoring the structural integrity and normal cellular composition of the lung tissue.

The development of coronavirus infection outbreak into a pandemic, coupled with the lack of effective COVID-19 therapies, is a challenge for the entire pharmaceutical industry. This study aimed to assess the treatment and preventive efficacy of the amino acid-peptide complex (APC) in male Syrian hamsters infected with SARSCoV-2 (intranasal administration of 26 μl of the virus culture, titer of 4 × 104 TCD50/ml). In a modeled COVID-19 case, APC administered for treatment and preventive purposes reduced lung damage. Compared to the positive control group, test group had the lung weight factor 15.2% smaller (trend), which indicates a less pronounced edema. Microscopic examination revealed no alveolar edema, atypical hypertrophied forms of type II alveolocytes, pulmonary parenchyma fibrinization. The macrophage reaction intensified, which is probably a result of the APC-induced activation of regenerative processes in the lung tissues. Spleens of the animals that received APC for therapeutic and preventive purposes were less engorged and had fewer hemorrhages. The decrease of body weight of the test animals that received APC for treatment and prevention was insignificant (p < 0.05), which indicates a less severe course of COVID-19. Administered following a purely therapeutic protocol, APC proved ineffective against SARS-CoV-2 post-infection. Thus, APC-based drug used as a therapeutic and preventive agent reduces pulmonary edema and makes morphological signs of lung tissue damage less pronounced in male Syrian hamsters infected with SARS-CoV-2.

The aimof the study was to carry out meta-analysis of randomized controlled trials in order to combine the results of clinical trials on Triazavirin®(Riamilovir) efficacy in the etiotropic therapy of acute respiratory viral infection.Materials and methods.The studies included 435 patients with a confirmed diagnosis of acute respiratory viral infection or ARVI (with laboratory confirmed absence of influenza virus antigens). The research was carried out in 27 centers. In studies, patients were divided into 3 groups in a 1:1:1 ratio (a total of 145 people per group). Each study included a group taking 100 mg of the medication 5 times a day, a group taking 250 mg of the medication 3 times a day and a placebo 2 times a day, as well as a group taking a placebo 5 times a day. The analysis was carried out in accordance with the PRISMA principles regarding the quality of information presentation on the results of systematic reviews and meta-analyzes of works evaluating the effects of medical interventions.Results. The conducted meta-analysis showed that the use of Triazavirin®(Riamilovir) has a statistically significantly effects on the severity of clinical symptoms in patients with ARVI. The performed meta-analysis confirmed reliable associations between the use of Triazavirin®(Riamilovir) in both doses and the chance of a persistent improvement in clinical symptoms on the 5thday of therapy. The meta-analysis also confirmed the statistical significance of the clinical effects of Riamilovir by such indicators as the area under the curve «point on the scale showing the severity of the condition in a patient with ARVI in relation to time», the proportion of patients with complete alleviation of all symptoms by the end of the 5th day from the start of therapy.Conclusion.The clinical trials proved that the use of Triazavirin®(Riamilovir) is effective both in the initial and in the late stages of the disease, therefore, the drug can be used in the initial therapy of adult patients with respiratory diseases of viral etiology.