Biological significance of the CD38 molecule goes beyond its metabolic, enzymatic, and proliferative functions. Possessing the functions of both an exoenzyme and a receptor, CD38 is actively involved in the mechanisms of adhesion, migration, intercellular signaling, formation of immune synapses, and modulation of a wide range of immune and non-immune cells. However, the detection of CD38 in mast cells (MC) on formalin-fixed and paraffin-embedded organ sections has not been previously performed.

The aim of the study was to evaluate immunohistochemically cytological and histotopographic features of CD38 distribution in MC of the skin, breast, palatine tonsils and bone marrow.

Materials and methods. In accordance with the design of the experiment, the authors studied biomaterial of organs from patients with neurotrophic skin ulcers, tonsillitis, mastocytosis, breast cancer, and pancreatic adenocarcinoma. CD38 was detected immunohistochemically; multiplex staining technology was used to study cytotopographic patterns of the enzymes distribution in MC and to identify the features of their histotopography.

Results. The possibility of immunohistochemical detection of CD38 in MC on histological sections of various organs was shown for the first time. CD38 expression was detected in a smaller part of the MC population and was characterized by wide variability from mild to pronounced levels. The content of CD38 in MC had organspecific features and also depended on the development of pathological processes in a specific tissue microenvironment.

Conclusion. Multiplex immunohistochemistry technologies allow detecting CD38 expression in mast cells and studying interaction of mast cells with other CD38+-targets in tissues, developing novel ideas about the mechanisms of realization of the preformed secretome component effects in normal and pathological conditions.

Currently, the growing interest in the structure of the vascular stream of the colon is due to the rapid development of abdominal and colorectal surgery.

The aim of research was to study the variant anatomy of the sigmoid branches of the inferior mesenteric artery in men and women.

Material and methods. The study included findings of multi-slice spiral computed tomography; a total of 2300 computed tomograms of adults aged 25 to 75 years (913 men and 1387 women) were investigated. Variants of the architectonics of the inferior mesenteric artery were differentiated by the presence and nature of the origin of its sigmoid branches, for which standard axial images and a series of post-processing images were used.

Results. There have been identified sequential, stem and mixed types of branching of the inferior mesenteric artery. In the sequential type, the left colic and all sigmoid arteries separate from the inferior mesenteric artery; with a stem, two or more branches depart from the inferior mesenteric artery by a common vessel; in the mixed type, two left colic arteries sequentially depart from the inferior mesenteric artery. It has been proven that in both sexes the predominant type of branching of the inferior mesenteric artery is the stem: in men it is noted in 62% of cases, in women – in 63%, the mixed type of branching of the inferior mesenteric artery is the rarest, noted only in 2.4% of cases.

Conclusion. The obtained information is of practical significance in abdominal, vascular, X-ray endovascular surgery, transplantology, coloproctology, and radiation diagnostics.

The aim of research was to study the distribution of histamine in macrophages and mast cells of the lung structures in autopsy material in certain forms of secondary tuberculosis.

Material and methods. The authors examined 165 cases of secondary pulmonary tuberculosis. The study included 500 histological specimens of male patients, aged 30 to 55 years, divided into 5 groups depending on the forms of secondary tuberculosis., The luminescent-histochemical method of Cross was used to determine the content of histamine in the lung structures; the specimens were further exposed to re-staining with hematoxylin and eosin.

Results. Histamine-containing specific alveolar and interstitial macrophages and mast cells were detected when studying autopsy material from the lungs of "nominally healthy" people. The highest content of histamine in the lung structures of this group was recorded in interstitial macrophages. In acute focal tuberculosis, there was an increased content of histamine in intra-alveolar and interstitial macrophages, with a simultaneous decrease of this bioamine in mast cells. In fibro-focal tuberculosis, the content of histamine exceeded the control parameters in all the studied cellular lung structures, with the highest content in mast cells. In infiltrative tuberculosis, there was detected an infiltrative luminescent track from lymphocytes together with the maximum luminescence of histamine. In acute cavernous and fibrous-cavernous tuberculosis, total degranulation of mast cells was observed. The content of the studied bioamine significantly decreased in interstitial macrophages compared to the control group.

Conclusion. The study of small forms of secondary tuberculosis detected an increased concentration of histamine in intra-alveolar and interstitial macrophages. Its maximum accumulation in all cellular structures was registered in the infiltrative form of tuberculosis. In destructive forms of tuberculosis, histamine was detected only in macrophages, which appeared to be the regulatory link of specific inflammation. The literature data and the results obtained allow us to report on the influence of Mycobacterium tuberculosis as a corpuscular antigen that causes destruction of structures that produce and metabolize neuroamines in the lungs.

The aim of the study was to present differences and regularities in the macro- and microscopic structure of the muscle tendons of the limbs identified by comparative analysis and generalization of the obtained findings.

Material and methods. The study included transverse histotopograms of 519 tendons of 17 different muscles of the upper and lower limbs. Histotopograms were received from 93 human cadavers and amputated limbs of 10 patients. Transverse sections of tendons up to 20 μm thick were stained with picrofuchsin according to Van Gieson, and hematoxylin–eosin. Histotopograms were studied and photographed using a stereoscopic microscope MBS-10.

Results. The authors have generalized data on the macro- and microscopic structure of the limb tendons. General regularities of the internal macro- and microscopic structure of the tendons have been specified. It has been demonstrated that these regularities are of applied relevance for improvement of restorative tendon microsurgery. Individual differences and differences between the tendons of different muscles at the structural level were revealed: the number, size, architectonics of the tendon bundles of the 1st order. Tendon bundles of the 1^st  order are the main structural units of the macro- and microscopic structure of the limb muscle tendons. Depending on the size of the cross-sectional area, they can be divided into small (0.004–0.009 mm2), medium (0.01–0.04 mm2), large (0.05–0.09 mm2) and very large (0.1–0.5 mm2). There were detected differences in the number, ratio and architectonics of the tendon bundles at different levels within one tendon; this allows assuming division and fusion of tendon bundles of the 1st order throughout the tendon.

Conclusion. The macro- and microscopic structure of the muscle tendons of the upper and lower limbs demonstrates general regularities and differences in the structure of the various muscle tendons, the fact being of theoretical and applied significance.

The aim of the investigation was to study the quantitative morphometric characteristics of the lymphoid follicles in the walls of the urinary tract using the method of macro-microscopy.

Material and methods. The topography, number and size of lymphoid nodules in the walls of the ureters, bladder and urethra obtained from the corpses of 142 people of different ages were studied by macro-microscopy using a binocular stereomicroscope MBS-9 after elective staining with Harris's hematoxylin. The material was taken from persons whose death was due to injuries and asphyxia, and autopsy showed no signs of pathology of the urinary organs. For statistical data processing, parametric statistics methods based on the Statistica 6.0 program were used. Statistical data processing included the calculation of arithmetic mean indicators, their errors, analysis of the amplitude of the variation series of each indicator.

Results. Lymphoid nodules are permanent structures in the walls of the ureters, bladder, and urethra. The number of lymphoid structures is maximum in the 1st period of childhood. In subsequent age periods, regardless of organ affiliation, the number of lymphoid nodules decreases with age, reaching a minimum in old age. In the 1st period of childhood, the maximum values are also reached by the size indicators of lymphoid nodules, increasing in the walls of the right ureter by 5.06 times, the left ureter – by 5.22 times, the bladder – by 4.60 times, the male urethra – by 4.60 times, female urethra – 4.65 times compared with the neonatal period (p<0.05). In the future, a decrease in size is observed, which is most pronounced in old age in the walls of the female urethra. Regional (organ) differences are in a smaller number of lymphoid nodules and their size in the walls of the ureters and the maximum value of these parameters in the walls of the urethra.

The aim of the study was to present structural and morphometric changes in the sensorimotor cortex neurons of the rat brain after ligation of the common carotid arteries (LCCA).

Material and methods. Cerebral ischemia was modeled in white Wistar rats by irreversible bilateral ligation of common carotid arteries (2-vessel model of incomplete global ischemia, without hypotension). For morphological studies, histological (hematoxylin–eosin, thionin staining according to the Nissl method), immunohistochemical (NSE, GFAP) and morphometric methods were used. The control group consisted of intact animals (n=6), the material was taken 1, 3, 7, 14 and 30 days after the experimental modeling of LCCA (n=30). Morphometric analysis was performed on preparations of frontal sections of the brain using the ImageJ 1.53; statistical hypotheses were tested using the Statistica 8.0.

Results. It was found that the number density of normochromic neurons decreased throughout the study period and reached its minimum values 30 days after LCCA: the decrease in layer III was 75.9%, and in layer V it was 72.6%. There was a decrease in the total number density of neurons. After 1 and 3 days, in layers III and V, the content of hyperchromic neurons with intact shape of perikarya increased. The numerical density of hyperchromic neurons with a spindle-shaped perikaryon, a deformed nucleus, as well as neurons with a homogeneous cytoplasm had maximum values after 30 days.

Conclusion. After irreversible bilateral LCCA, together with an increase in the number density of hyperchromic pycnotic neurons, as well as neurons with homogenization of the cytoplasm and nucleus, a decrease in the NSE content in the cytoplasm of pyramidal neurons was noted, which may indicate a decrease in the expression of this protein and a decrease in the functional activity of neurons by the end of the study period. An increase in hyperchromic pycnotic neurons and shadow cells against the background of a decrease in the number density of normochromic and hyperchromic non-pycnotic neurons may indicate a significant severity of the processes occurring after LCCA and the irreversibility of destructive changes in nerve cells.

The aim of this study was to find out the microscopic and ultrastructural features of somatotropic endocrinocytes in two rare mammalian species in postnatal ontogenesis.

Material and methods. We used material from river beavers (Castor fiber L.) and sea otters (sea beaver, Enhydra lutris), listed in the Red Book of the Russian Federation. The collection of material was carried out in the Voronezh Reserve and on the rookeries of marine mammals on the Commander Islands (Bering Island, Medny Island). To fix the material, Shteve, Bouin, and Zenker liquids were used. Paraffin sections were stained with hematoxylin and eosin, aldehyde fuchsin according to Helmi–Dyban. The linear dimensions of cell structures were measured, the cross-sectional area of cells and their nuclei was calculated, and the nuclear cytoplasmic index was calculated. The numerical density of somatotropic endocrinocytes in the field of view was determined. For electron microscopy, pituitary specimens were fixed in 2.5% glutaraldehyde and 1% osmium fixative. Sections were prepared on BS-490 and LKB-4800 ultramicrotomes. Sections were counterstained with uranyl acetate and lead citrate and studied under a Tesla BS-500 electron microscope.

Results. In river beavers and sea otters at the age of 6 months, compared with newborn animals, the number of somatotropic cells in the center of the pituitary gland increases by 3.46 (p<0.05) and 3.32 times (p<0.05), respectively, and in the lateral zones – 2.61 times (p<0.05) and 3.39 times (p<0.05); cell cytoplasm area – 1.96 times (p<0.05) and 1.85 times (p<0.05); the area of the nuclei – 1.48 times (p<0.05) and 1.30 times (p<0.05). In river beavers and sea otters at the age of one year, compared with six-month-old animals, an increase in the number of somatotropic cells in the center of the pituitary gland by 1.27 times (p<0.05) and 1.33 times (p<0.05) was revealed; and in the lateral zones by 1.08 times (p<0.05) and 1.02 times (p>0.05); and area of the cytoplasm of cells, respectively – 1.29 times (p<0.05) and. 1.25 times (p<0.05). The maximum indicators of secretory activity of somatotropic cells were found in river beavers and sea otters at the age of 1 year.

Oligodendrocyte progenitor cells (OPCs) were first described more than two decades ago. New marker techniques have revealed that they are independent cells with the high nerve tissue repair potential, and they have been classified as the fourth glial cell type in addition to astrocytes, oligodendrocytes and microglial cells. Another term used for this type of cells is polydendrocytes, this is due to both their morphology and developing knowledge of their diverse functions. OPCs play an important role in the development and myelinogenesis in adults giving rise to oligodendrocytes that cover axons providing signal isolation by the myelin sheath, thus accelerating action potential propagation and ensuring high transmission fidelity without the need for an increased axon diameter. Loss or absence of oligodendrocyte precursors and the resulting absence of differentiated oligodendrocytes are associated with lost myelination and subsequent impairment of neurological functions. Demyelination is a feature of various diseases such as multiple sclerosis, Alzheimer's disease, schizophrenia, infantile cerebral palsy and childhood cognitive impairment. Moreover, OPCs express receptors for various neurotransmitters and are exposed to membrane depolarisation to receive synaptic signals from neurons. Numerous research studies have been investigated polydendrocyte functionality and potential for use as target cells in the treatment and prevention of neural tissue diseases. There are no studies related to morphology, functionality and potential of oligodendrocyte precursors in our country. In this review we highlight issues of the polydendrocyte discovery, their localization and migration potential, possibilities of remyelination through OPCs in hypoxic injury in the embryonic and postnatal period.

The issues of studying the mechanisms of skin aging continue to be relevant, due to the intensive development of cosmetology and various methods for restoring physiological parameters after destructive violations of the integrity of the skin. Skin aging due to internal and external factors can significantly change the structure and function of the epidermis and dermis, and may be associated with a large number of complications in various dermatological conditions, in that senescent dermal fibroblasts modify the tissue microenvironment through changes in their cellular factors and extracellular matrix. The paper presents data on the normal structure of the skin, the features of its vascularization, a review of the literature on the influence of various factors of the external and internal environment on the structure of the skin, taking into account age-related features, summarizes the structural changes in the skin in the age aspect, the main molecular mechanisms that explain these changes. Numerous studies confirm that skin aging is caused by a complex effect of various factors that are associated both with a change in the physiological mechanisms of regulation of the processes of the intracellular and extracellular matrix, and with the influence of environmental conditions.

The aim of research was to characterize the subject and object of scientific research by the employees of the department of histology and embryology of the Kursk State Medical Institute in the second half of the XX century and their contribution to the development of ideas about the microscopic structure of the nervous system.

Material and methods. The main research methods were source study and historical genetic analysis. As sources of personal and scientific biography, we used the personal files of the employees of the department of histology and embryology, stored in the State Archive of the Kursk Region, as well as collections of their dissertations and published scientific papers from the library of Kursk State Medical University. The article shows the contribution of the representative of the scientific school A.S. Dogel, Doct. Biol. Sci., Professor Z.N. Gorbatsevich, to the formation of the neuromorphological school of the department of histology and embryology of the Kursk State Medical Institute.

Results. The article shows the contribution of the representative of the scientific school A.S. Dogel, Doct. Biol. Sci., Professor Z.N. Gorbatsevich, to the formation of the neuromorphological school of the department of histology and embryology of the Kursk State Medical Institute. The results of collaboration of the staff of the department of histology and embryology with the leading neuromorphologists of our country – Professor V.M. Ugryumov, professor V.P. Kurkovsky, professor T.A. Grigorieva and Professor G.A. Koblov. The results of studying the reactions of the immune and nervous systems to the implantation of foreign bodies in the brain are shown; studies of the possibility of regeneration of nervous tissue after ischemia, blood loss and mechanical damage; the development of neuroendocrine research and research into the functions of the hypothalamus using the method of implanted electrodes.

The article focuses on the milestones of George Hoyt Whipple, who was a Nobel Prize Winner, pathologist, one of the major researchers of anemia, pigment metabolism, liver and pancreatic lesions, tuberculosis, parasitic diseases. He contributed significantly to biology and medicine. The authors briefly outline a biography of a well-known scientist, his significant contribution to the development of various branches of science, his landmark studies related to the role of the liver in the treatment of pernicious anemia. Modern aspects of the etio-pathogenesis of Whipple's disease are discussed.