�. V. Tyurina

Introduction.Currently, there are different approaches to assessing changes that occur in ischemic myocardium in patients with chronic coronary artery disease (CAD). Researchers argue about the timing and completeness of the restoration of myocardial dysfunction areas. We aimed to assess hibernating myocardium in the zones of hypokinesia in patients with CAD. Materials and methods. We performed a morphological and immunohistochemical study of left ventricular myocardial biopsies of 25 patients who underwent surgical reconstruction of the left ventricle with surgical revascularization. Results. Morphological and immunohistochemical studies revealed violated morphological structure of cardiomyocytes. It correlates with the accumulation of MMP9 in the cytoplasm of cardiomyocytes in the areas of affected myocardium in ischemia against the background of partial or complete destruction of CM basement membranes formed by type IV collagen. It also correlates with long-term consequences of treatment. Conclusion. As a result of the destructed structure of sarcomeres and cardiac basement membrane hibernating myocardium is unable to provide a contractile function in the future. Morphological examination showed that viable cells were likely to function only as a protective mechanism in early scar formation. Keywords: left ventricular remodeling, hibernating myocardium, basement membrane, cardiomyocytes, matrix metalloproteinase 9, type IV collagen

Changes in the activity of the renin-angiotensin-aldosterone system are responsible for a stable shift in the regulation of the cardiovascular system in essential hypertension (EH). They can be characterized as hemodynamic allostasis. The purpose of our study was to determine the role of hemodynamic parameters in allostatic load in patients with EH without metabolic syndrome. Twenty-four hours of ambulatory blood pressure monitoring was performed, followed by linear and non-linear rhythm analysis. Based on the daily index, patients with EH were divided into two groups: group 1-patients with no significant nighttime decrease in blood pressure (BP); group 2-patients who had a nocturnal decrease in BP. The control group included healthy persons aged 25 to 69 years. A linear analysis was used to determine the mean values of systolic and diastolic BP, heart rate (HR), time load of BP, circadian index, and structural point of BP. Non-linear analysis was applied to determine the mesor, amplitude, range of oscillations and % rhythm of BP and HR. The allostatic load index (ALI) was also calculated on the basis of the corresponding biomarkers. It was found that ALI was significantly higher in groups 1 and 2 in comparison with the control group. The hemodynamic mechanisms of this increase were different.

Background: Research into the pathogenesis and morphogenesis of new coronavirus infection (COVID-19) is currently a hot topic that requires the accumulation, management and analysis of the data. Understanding the mechanisms of the disease and their characteristics would help to improve diagnostic quality, treatment efficacy and reduce mortality. Aim: To identify morphological and immunohistochemical characteristics of the bronchopulmonary lymph node tissues in autopsied patients with COVID-19. Materials and methods: The study was carried out on 44 autopsy samples from patients who were hospitalized and died from the new coronavirus infection COVID-19 in the Moscow Regional Research and Clinical Institute. Macroscopic, histological, and immunohistochemical assessment methods were used. Results: We found stereotypical abnormalities in the morphology and cellular composition of the lymphoid tissue depending on the duration of the disease. These included signs of B-cell-mediated immunity suppression manifested by a decrease in the number and size of lymphoid follicles and occurs at latest after 7 days from the onset of the disease. In the patients with the disease duration of up to 14 days, the T-cell pool of the lymph nodes is represented mainly by CD4 + T-lymphocytes. With longer duration of the disease, there is a gradual increase in the number of lymphoid follicles and their sizes, with changes of the CD4 + to CD8 + T-cell ratio towards higher CD8 + counts. After 21 days of the disease, the CD4 + to CD8 + ratio levels off. Conclusion: The results obtained indicate a direct damaging effect of SARS-CoV-2 on the lymph node tissues of the bronchopulmonary group. The possibility of secondary transient immune deficiency and infectious complications in patients with a new coronavirus infection is discussed.