Background There is still insufficient knowledge with regard to the potential involvement of mast cells (MCs) and their mediators in the pathology of coronavirus disease-2019 (COVID-19). Therefore, our study aimed to investigate the role of MCs, their activation and protease profiles in the pathogenesis of early and late lung damage in COVID-19 patients. Methods Formalin-fixed and paraffin embedded lung specimens from 30 patients who died from COVID-19 and 9 controls were used for histological detection of MCs and their proteases (tryptase, chymase) followed by morphometric quantification. Results Our results demonstrated increased numbers of MCs at early stage and further augmentation of MCs number during the late stage of alveolar damage in COVID-19 patients, as compared to the control group. Importantly, the percentage of degranulated (activated) MCs was higher during both stages of alveolar lesions in comparison to the controls. While there was no prominent alteration in the profile of tryptase-positive MCs, our data revealed a significant elevation in the number of chymase-positive MCs in the lungs of COVID-19 patients, compared to the controls. Conclusions MCs are characterized by dysregulated accumulation and increased activation in the lungs of patients suffering from COVID-19. However, future profound studies are needed for precise analysis of the role of these immune cells in the context of novel coronavirus disease.

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Background: New coronavirus infection (Covid-19) in patients with diabetes type 2 mellitus (DM) often has severe clinical course and manifestation. This comorbidity is a reasonable indication for vaccination. Male patients are often concerned about the vaccination impact on their fertility, so the current research of this issue seems to be essential and relevant.Aims: To evaluate the quality of ejaculate in type 2 diabetes mellitus (DM) patients, vaccinated by GamCovidVac (Sputnik V).Materials and Methods: The pilot observational prospective study included 30 males with type 2 diabetes mellitus (DM). The study continued from February 2021 till June 2021. The research design involved medical history analysis, glycated hemoglobin (HbA1c) tests, total testosterone level in blood measurement, semen analysis (sperm count test). Group comparison was performed by Wilcoxon Signed Ranks Test. The differences were considered statistically significant at p<0.05.Results: After vaccination 19 patients (63%) demonstrated a temperature rise which lasted for 2 days; 26 patients (87%) complained of tenderness in the injections site which lasted up to 5 days. Though a few patients reported general somatic side effects after the vaccination, there have been no statistically significant deviations in sperm count, viability, function and morphology. The levels of glycated hemoglobin and total testosterone remained unchanged.Conclusion: The study revealed no negative impact of GamCovidVac on ejaculate quality, total testosterone level and compensation of carbohydrate metabolism.

The paper describes methods for generating (modeling) representative driving cycles of the vehicle used to solve engineering problems in the design of electric vehicles, such as resource calculations, determination of the required capacity of traction batteries and evaluation of power reserve, etc. The general approaches used in the processing of real traffic data and algorithms for modeling driving cycles using deterministic and probabilistic approaches are described. This paper presents driving cycles that ensure convergence with parameters corresponding to the real conditions of vehicle movement. The developed driving cycles can be used in the design of electric vehicle transmission components and allow for the analysis of operational properties.

Mast cells cyclically synthesize and excrete a wide range of biogenesis products with different biological activities into the extracellular matrix and are regulators of local homeostasis both in normal conditions and in pathology – inflammation, oncogenesis, etc. The relative specificity of classical histochemical methods for detecting mast cells in relation to chromogenic to substrates causes certain difficulties in the selective study of the components of the secretome of mast cells, for example, heparin, histamine, chymase or tryptase. Therefore, immunomorphological techniques have become very popular, which identify specific substrates and allow differentiation of the components of the mast cell secretome. Mediators produced by mast cells promote neoangiogenesis, fibrillogenesis and re-epithelialization during the repair process.The aim of our work was to study the tryptase profile of the mast cell population of rat skin during the wound processusing an original combined method of immunohistochemical staining.Material and methods. The experiment involved 12 Wistar rats divided into two groups – intact (n=6) and with the existing wound process of the skin in the withers (n=6). The tryptase profile of mast cells was assessed on the 7th day of the wound process in comparison with the control group.Results. The results obtained showed a significant increase in the number of tryptase-positive mast cells on the 7th day of the wound process in the skin against the background of a general increase in the population of mast cells. Intragranular tryptase reserve was significantly increased. In contrast to the control, where mast cells with single tryptase-positive granules dominated, during the wound process, cells of this type were practically not detected in the skin (43.69±2.9% and 8.55±0.9%). The content of tryptase-positive mast cells with complete filling of the cytoplasm in the control group and the group of animals with a wound process was 14.24±1.2% and 38.03±2.9%, respectively.Conclusion. Thus, when modeling a wound, an increase in tryptase synthesis is detected both in individual MCs and within the entire MC population. This fact indicates that mast cell proteases can become a potential therapeutic target for improving wound regeneration by correcting immunogenesis, inflammation and fiber formation.

The mechanisms of regeneration for the fibrous component of the connective tissue of the dermis are still insufficiently studied. The aim of this study was to evaluate the effectiveness of the use of molecular hydrogen on the local therapy of a II degree burn wound with the intensification of collagen fibrillogenesis in the skin. We analyzed the involvement of mast cells (MCs) in the regeneration of the collagen fibers of the connective tissue using water with a high content of molecular hydrogen and in a therapeutic ointment for the cell wounds. Thermal burns led to an increase in the skin MC population, accompanied by a systemic rearrangement of the extracellular matrix. The use of molecular hydrogen for the treatment of burn wounds stimulated the regeneration processes by activating the formation of the fibrous component of the dermis, accelerating wound healing. Thus, the intensification of collagen fibrillogenesis was comparable to the effects of a therapeutic ointment. The remodeling of the extracellular matrix correlated with a decrease in the area of damaged skin. Skin regeneration induced by the activation of the secretory activity of MCs may be one of the possible points of implementation of the biological effects of molecular hydrogen in the treatment of burn wounds. Thus, the positive effects of molecular hydrogen on skin repair can be used in clinical practice to increase the effectiveness of therapy after thermal exposure.

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The paper presents a novel histochemical approach for evaluation of tryptase expression in the mast cell population. To study the selective effect of mast cells (MC) on the parameters of a specific tissue microenvironment, it is necessary to detail the molecular composition of their secretome and analyze the pathways of degranulation. The developed method for combined immunomorphological and histochemical tryptase staining protocols contributes to a more objective determination of the integral level of specific protease expression in the skin MC population. Extra visualization potentials of cytological features and specific aspects of tryptase processing expand efficiency of morphological analysis in both normal and pathological conditions.