[CHARACTERISTICS OF THE REACTIONS OF THE SPLEEN LYMPHOID STRUCTURES IN MICE IN A TERRESTRIAL EXPERIMENT AND AFTER A PROLONGED SPACEFLIGHT].

Morphometric methods were used to examine the cell composition of the germinal centers of lymphoid nodules and periarteriolar lymphoid sheaths (PALS) in male C57/b16 mice aged 19-20 weeks after 30-day-long space flight, simulation of space flight factors in a terrestrial experiment and in vivarium control group. After a ground-based experiment, compared to vivarium control, the functional activity of morphological zone of T lymphocyte maturation was decreased in PALM. In the germinal centers of lymphoid nodules of mice subjected to a ground-based experiment, lymphocytopoiesis and cell blast transformation, that characterize the morpho-functional activity of this zone and humoral immunity, remained unchanged. After a spaceflight, as compared with ground-based experiment, the changes of cell composition were less expressed in PALS than in the in the germinal centers of lymphoid nodules. It is concluded that PALS are more stable morphological zones, while the germinal centers of lymphoid nodules in the spleen are specific "target zones", most sensitive to a variety of factors of a space flight.

[Esophageal wall structure in people of elderly and senile age].

Using histological methods, the esophageal wall structure and the cytoarchitectonics of mucous membrane were studied in the individuals of elderly (n = 5) and senile (n = 10) age. The control group included the individuals of I (n = 3) and II (n = 3) periods of mature age. It was demonstrated that with advancing age in most cases the destructive processes took place in the epithelium (delamination of the layer, separation of large fragments, formation of microerosions etc.) in most of the studied cases. Lymphocytes, neutrophils and eosinophils were found between the epithelial cells; the numbers of infiltrating cells was increased 2-3 times during aging. Mucosal lamina propria and the submucosa, in particular, were characterized by the thickening of the bundles of collagen fibers. A two-fold increase in the number of the cells of the fibroblast lineage was found. The number of leukocytes in the lamina propria was increased by the eldery age in the upper and lower parts of the esophagus (3.5 and 1.75 times respectively). The changes in lamina muscularis were manifested by its thinning, delamination and myocyte dissociation. Remodeling of the muscular tunic was less pronounced. The degree of changes increased distally and varied widely depending on the individual peculiarities.

[Structural organization of the duodenal wall and its lymphoid tissue in the persons of elderly age].

Structural organization of the duodenal wall was studied in older men (aged 70-75 years, n=15), and its lymphoid tissue was examined using the qualitative and quantitative analysis. Deformation, flattening and sparseness of the intestinal villi were identified. Atrophic phenomena in the organ mucous membrane were accompanied by the destruction of the cells of surface epithelium, crypts and glands. Simultaneous infiltration of the lamina propria with lymphocytes, eosinophils, neutrophils and malfunctions in a microcirculatory bed is indicative of the presence of inflammatory processes. The duodenum of the elderly persons was characterized by the disruption of the integrity of the lamina muscularis mucosae that lead to the displacement of the duodenal glands from submucosa to the lamina propria. The suppression of cell proliferative activity, decreased blast transformation activity, in the lymphoid tissue of the intestine, along with a high degree of cell destruction, lead to the weakening of local immunity in the elderly persons.

[Morphological peculiarities of interrelations of lymphoid nodules, lymphatic capillaries and lymphocyte migration in the wall of intestine and trachea].

The objective of this study was to identify the peculiarities of lymphocyte migration in lymphoid nodules of the mucous membrane of the caecum and the trachea in autopsy material, obtained from 25 healthy individuals of various ages (from the newborns to the persons of 1st mature age). Also, the tendinous center of diaphragm was studied in 10 healthy rabbits. Using histological methods, the presence of two functionally different types of lymphatic capillaries in the wall of the caecum was demonstrated. The first group includes numerous lymphatic capillaries located around the base of the lymphoid nodules. A large number of lymphocytes in portions enter the lumen of the capillaries, in accordance with the intestinal wall contractions. The second group includes the rest of the lymphatic capillaries, draining the intestinal wall and the capillaries of the trachea, resorbing mainly the interstitial fluid. The migration of lymphocytes from the lymphoid nodules of the trachea was directed, mainly, towards the surrounding tissues. Using the lymphatic capillaries of the diaphragm as a model, it was demonstrated that during the migration of the cells through the endothelium, argyrophilic structures - the stigmata, were formed which disappeared after the passage of the cells.

[Splenic lymphoid structures reorganization in gerbils after space flight].

To assess the effects of weightlessness on the organism of mammals, splenic lymphoid tissue was studied in 10 intact Mongolian gerbils and in 10 animals after a 12-days-long spaceflight. In experimental animals the body mass and splenic, thymic and adrenal mass indexes were sharply reduced. In the spleen, the red pulp area was significantly increased, there appeared the areas of fibrous tissue proliferation, and extensive hemorrhage. Lymphoid nodules with germinal centers disappeared, while periarterial lymphoid sheaths were depleted. Quantitative analysis of cellular content of the lymphoid structures of the spleen showed dramatic activation of cell destruction, lymphocytopoiesis suppression with the disappearance of mitotically dividing cells and a decrease in the number of blast cells. The absence of plasma cells indicates the suppression of the processes of the immunocytopoiesis. The complex of changes noted suggests the decrease of immunological barrier of lymphoid tissue in the spleen and in the whole organism, in gerbils under the conditions of weightlessness in the spaceflight.

[Age-related dynamics of morphofunctional state of the lymphoid tissue in the wall of human ureter].

Cellular composition of the lymphoid tissue in the ureteral epithelium and lamina propria was studied morphometrically in human postnatal ontogenesis using autopsy material obtained from 32 males of different age (from the neonatal period to the II period of mature age). Lymphoid tissue was found to be weakly developed in the ureteral wall during the studied period of human life. Processes of lymphocytopoiesis were not expressed, while there was high activity of cellular destruction. The reduction of the plasma cell numbers by the II period of mature age is a manifestation of a general decrease of functional activity of the lymphoid tissue in the wall of the ureter.

Structure of gastric wall in wistar rats in health and after experimental traumatic brain injury.

The structure of gastric wall was studied by histological methods in Wistar rats in health and after skull trephination and insertion of a needle into the brain. Experimental brain injury led to the development of destructive changes in the gastric wall (in the lymphoid structures located between the gland bottoms and muscle plate of the mucosa). Changes in the structure of cardiac glands and desquamation of the epithelium were detected. Microcirculation was disordered, signs of inflammation appeared. The counts of medium-sized lymphocytes and plasma cells increased in the layer of lymphoid cells and in the submucosa.

Cellular composition of the thymus in Wistar rats in experimental intracerebral hemorrhage.

The time course of changes in cellular composition of the thymus after experimental intracerebral hemorrhage was studied in rats with various prognostic resistance to emotional stress. Increased migration of T lymphocyte precursors to the subcapsular zone, activation of T lymphocyte differentiation in the thymus, reduced number of mitotic cells, destruction and intensive migration of thymocytes from the thymus were observed. The severity of changes in cell composition in all layers of the thymus after experimental intracerebral hemorrhage was different in rats resistant and predisposed to emotional stress. Predisposition to emotional stress and stress before surgical modeling of intracerebral hemorrhage affected the severity of changes in the thymus. It is shown that autoimmune and adaptation mechanisms, which are closely interrelated, play an important role in the pathogenesis of the intracerebral hemorrhage.

[Morphological characteristics of the Wistar rat thymus in experimental intracerebral hemorrhage].

The purpose of the present investigation was to study thymus structure in 108 Wistar rats possessing different prognostic resistance to an emotional stress under the conditions of experimentally modeled intracerebral hemorrhage. It was demonstrated that after the intracerebral hemorrhage, the thymus underwent changes that were associated with both the stereotyped response to stress and the development of an immune response against the damaged brain tissue: relative thymus mass and the cortico-medullary index were shown to decrease, while the volumetric fractions of the capsule and connective tissue septa were increased. The reaction of the vascular bed included stasis, diapedesis and perivascular edema. These changes were more expressed in the rats predisposed to an emotional stress.

[The new method of the blood loss evaluation].

The quantification of the acute blood loss remains to be the crucial task of the emergency aid. There is no satisfactory and practically suitable method of the blood loss measurement to present day. The original method is based on the electrolyte blood characteristics' measurement. The compact and handy device allows measure the blood loss amount within minutes, which is mostly important at preadmission stages.

[Immune mechanisms in the development of hemorrhagic stroke].

The role played by immune mechanisms in intracerebral hemorrhage (ICH) was evaluated based on the studies of thymus structure and cell composition in rats showing different degree of tolerance to emotional stress. A new experimental ICH model is proposed. It is concluded that both stereotype and autoimmune mechanisms are involved in the development of ICH.

[Lymphatic system and its significance in immune processes].

Up to 80-90th of XX century, lymphatic system was considered as a part of vascular system, performing the functions of drainage of tissue fluid from the organs, in addition to the venous system. In the second half of XX century, detailed research of the organs of lymphatic system, and of lymph nodes in particular, lead to the understanding of a defensive role of this system, which participated in the elimination of foreign (potentially dangerous) particles--fragments of dead cells and other tissue elements. Tissue fluid containing these substances, is absorbed into lymphatic capillaries (where it gains the name of lymph), flows through the lymphatic vessels to the lymph nodes, which serve as lymph biological filters. In the lymph nodes, the foreign particles are detained on the fibers of the reticular meshwork, where they are recognized by lymphocytes and are eliminated with the help of macrophages. After passage through the lymph nodes, cleared lymph flows into the blood through lymphatic ducts and trunks, which are continuous with the large veins in the lower regions of the neck. Thus, the lymph nodes, that are the organs of immune system, which are formed by lymphoid tissue and possess special structures for the clearance of lymph (tissue fluid), are, at the same time, the organs of lymphatic system. Lymphatic capillaries and vessels provide the transport of the lymph (tissue fluid) to the lymph nodes and conduct the lymph to the blood.

[Inguinal lymph nodes of monkeys subjected to 8-days-long immersion in water].

The morphometric study of cytoarchitecture of the structural and functional components of lymph nodes of male monkeys (Macaca mulatta) aged 4-5 years was performed after 8-days-long immersion in water. Activation of lymphocyte mitotic activity in lymphoid nodules (B-dependent zones) was demonstrated in association with an accumulation of small lymphocytes in them and an increase of macrophage reaction. Accumulation of mature forms of plasma cells was detected in all the structures of lymph nodes. It was also found that 8-days-long immersion in water resulted in remodeling of the vessels of lymph node microcirculatory bed, which was accompanied by changes of the endothelium in blood vessel wall and by disturbances of lymph drainage, that lead to accumulation of lymphocytes in lymph node sinuses.

Changes in the rat thymus cytoarchitectonics during repeated exposure to hypergravitation.

Comparative study of the structural and functional changes in rat thymus after 5-day and repeated 5-day exposure to hypergravitation (2g) showed less pronounced changes after repeated exposure. Proliferative potential of thymic lymphocytes was higher and their loss (death) was lower after repeated exposure to hypergravitation, which attested to better adaptation of the thymus during repeated prolonged exposure to hypergravitation than after single exposure of the same intensity and duration. Our findings suggest the possibility of the formation of gravitation memory in thymic lymphocytes during repeated long-term exposure to hypergravitation.

[Pathogenetic mechanisms of peritonitis in acute small intestinal obstruction].

Microscopic changes in the walls of strangulated small intestine, morphology of their vascular and resorption elements, adaptive mechanisms were studied in experimental acute small intestinal obstruction. It is demonstrated that the main factor of pathogenesis of peritonitis in strangulate and obstructive small intestinal obstruction is morphofunctional changes of intraorganic microcirculation of the small intestine.

[Structures ensuring blood flow control in the vessels of microcirculatory bed].

The aim of this study was to investigate the morpho-functional mechanisms of blood flow regulation in the vessels of the microcirculatory bed in various organs of man and animals (rabbitts and dogs). Ranvier's and Rasskazova's methods of silver nitrate impregnation, histological section staining with hematoxylin-eosin and after van Gieson, Gomori's method for demonstration of acid and alkaline phosphomonoesterases were used to detect the presence of the structures within the vessels of the microcirculatory bed that are capable of changing the blood flow through their lumen. These mechanisms can be temporary, and their activity is associated with the functional state of the endothelium (presence of microprojections, endotheliocyte swelling, changes of endotheliocyte orientation and laminar surface size). Permanent structures are located in microvessel walls (sphincters) and they possess high activity of acid and alkaline phosphomonoesterses. Arteriolar-venular anostomoses, direct transition of arterioles into the venules and peculiarities of microvessel branching are also attributed to the mechanisms of blood redistribution. Under pathological conditions some additional structures may develop that include polyp-like structures in capillaries and venules, intimal cushions, ampule-like expansions of the arterioles, varicose widening of venular orifices and vascular glomeruli.

Thymus recovery after intensive physical exercise under conditions of immunocorrection and without it.

Exogenous antioxidants, e.g. tocopherol, prevent undesirable changes in the thymus and accelerate its recovery after intensive physical exercise. Four weeks after the end of training (swimming) the general structure of the thymus and content of LPO products in rats treated with tocopherol corresponded to the control values, in contrast to animals receiving no correction.