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Background: Benzo[a]pyrene (BaP) is the widespread environmental toxicant with carcinogenic activity. BaP undergoes metabolic activation in the liver microsomal monooxygenase system, and its regional lymph nodes act as peripheral filters, purifying lymph formed in the liver. It remains an open question about the significance of the integral liver and lymphatic system work in supporting processes of adaptation and resistance to the BaP effects., Objective: The purpose of our investigation was to study structural and metabolic changes in the liver and its lymph region in males Wistar rats weighing 180-220g., Methods: Animals of the experimental group (n =20) daily for 3 days was performed BaP injections: intraperitoneal with 2 mg per 100g of body weight in 0.2-0.3 ml of olive oil. Rats in the control group (n =20) received in the same mode of injection of olive oil. The light and electron microscopy morphometric study of the liver and its regional lymph nodes morphometric analysis were performed. The intensity of lipid peroxidation in the liver was measured by the number of diene conjugates (DC), ketotriene conjugates (KC) and malondialdehyde (MDA)., Results: Simultaneous increase of the hepatic sinusoids relative area and the specific area of the regional lymph nodes sinus system under the BaP effect was found. At ultrastructural level dilatation of the Disse spaces, filling of cell detritus and collagen fibers bundles of these spaces were noted. Damage of nuclear apparatus, balloon transformation of granular endoplasmic reticulum profiles were found in hepatocytes, condensation of the mitochondrial matrix was observed. The relative squares of B-dependent zones increased and T-dependentparacortical zone reduced in the regional lymph nodes. The increase in the content of KC and MDA in liver was identified., Conclusion: benzo[a]pyrene causes interrelated cascade of reactions in the liver and in its lymphatic region: a disturbance of the blood-lymph barrier morphological organization, and so obstruction of the lymphatic drainagefrom the organ. These promotes development of tissue hypoxia and apoptosis, protein synthesizing and energy cell apparatus disruptions, formation of lymphoid tissue temporary infiltrates in the liver.

The effects of combined action of the industrial frequency magnetic field (MF) and continuous illumination (CI) on microcirculation, ultrastructural features of liver cells and apoptosis were studied in Wistar rats (n=56). It was found that in the liver of rats exposed to MF, CI and CI+MF for 14 days, parenchyma relative area was reduced, and that occupied by the sinusoidal capillaries was increased together with the liver vascularization coefficient. Combined exposure resulted in most pronounced ultrastructural changes (plasma membrane lysis in hepatocytes and endothelial cells, doubling of osmiophilic layers in tight intercellular junctions). Hepatocytes revealed condensed cytoplasm, mitochondria with electron-dense matrix, nuclear chromatin disintegration and nucleolar compaction. Hepatocyte intranuclear endonucleases were activated.

Using transmission electron microscopy, the ultrastructural organization of the endothelium of blood and lymphatic capillaries and the structures of the interstitium of synovial membrane were studied in the patients with osteoarthrosis of a knee joint of I-II and II-III stages. Material, obtained from the patients with traumatic lesions of the knee joint components, was used as a control. The structural signs indicative of the microcirculation and lymphatic drainage disturbances were detected in the synovial membrane and were most expressed in II-III stages of osteoarthrosis. These included: the decrease of the volumetric density of all the types of micropinocytotic vesicles and the cisterns of rough endoplasmic reticulum, the decrease of the numerical density of attached and free polysomal ribosomes, the accumulation of erythrocytes and thrombocytes in the lumen of blood capillaries, the increase of the number of open-type interendotheliocyte contacts in the lymph capillaries, the increase of the size and the decrease of the electron density of the pericapillary and the interstitial spaces.

A total of 75 males from married couples with circulatory prostatitis aged 19-47 were examined and treated in Barnaulsky sanatorium. The patients were trained by walking with the load power 80-110 W for 2.5 to 3 hours. They also received phytocorrection with biologically active food additive Fitopan M. The treatment led to attenuation of pelvic symptoms, stabilization of morning erection, normalization of friction period and laboratory indices. The effect persisted for 3 years.

The safety of the new enterosorbent noolit has been evaluated within the framework of its preclinical characterization. Single introduction of noolit to rats and mice (females and males) in maximum doses for intragastric administration (5.0 - 20.0 g/kg) does not lead to the loss of experimental animals. Single administration of large doses (5 - 40 times the effective dose) can reduce the growth of the total body weight and lead to the development of nonlethal pathological changes of hemopoietic organs, which is manifested by a weak regenerative anemia (5% of cases); neutrophile, eosinophile, and basophile leukocytosis (3% of cases); and a decrease in the glucose level in blood serum. In chronic experiments on rabbits, the administration of noolit for 3 months in a dose of 0.5 and 2.0 g/kg (2 and 8 times that recommended for humans) did not reveal any toxic action on the functional and morphological state of the main systems and organs (blood, liver, kidneys, lungs, heart, gastrointestinal tract, sex organs, etc.).

Light microscopy was used to study mesenteric lymph nodes in 46 neonatal infants who had died from small bowel atresia, inflammatory abdominal processes and diseases. There were no lymphoid follicles with germinative centers in the mesenteric lymph nodes of all neonatal infants, which seemed to result from the lack of antigenic stimulation during intrauterine development. Medullary substance malformation in the lymph nodes promotes the occurrence of inflammation in the region of their lymph collection and favors the progression and generalization of a pathological process.

Drainage and detoxication functions of lymphatic system at regional level are discussed. Lymphodetoxication is regarded as a unity of biophysical, biochemical and immune actions upon the lymph in lymphoid structures of an anatomical region. Regional lymphatic drainage is considered as a three-component mechanism, that includes interstitial pathways of non-vascular microcirculation, regional lymphatic vessels and lymph nodes. As a whole, this construction represents a lymphatic region, that includes, besides the pathways of vascular and non-vascular lymph circulation, other lymphoid structures, which are present in this region (individual cells, constant and temporary aggregations of lymphoid tissue).

Using the methods of light and electron microscopy as well as histochemistry, the complex study of structural-cellular state of the wall of small intestine and its grouped lymphoid nodules, mesenterial and iliac lymph nodes and thymus was performed in rats subjected to the changes of a type of drinking water. Tap, distilled and radon waters were used. The organism was found to respond to the changes in the type of drinking water by both non-specific (increase in sectional area of lymphatic vessels and the number of eosinophilic granulocytes in the wall of small intestine, in lymphoid nodule number containing germinal centers in lymph nodes, in proportion of thymus connective tissue component, increased lymphocyte dehydrogenase activity) and specific reactions, which were characteristic only to a given type of water. The latter, for example, included the activation of the function of protein synthesis in endothelial cells of lymphatic capillaries of the small intestine and increased numbers of plasma cells and dividing cells in lymphoid organs in rats consuming distilled water; increased proportion of blood capillaries in the wall of the small intestine, accompanied by the ultrastructural signs of reduction of plastic processes in them in animals drinking radon water. The response of the wall of the small intestine and lymphoid organs of an animal to the effect of drinking waters, different in their mineral content and radon concentrations, was subjected to general biological regularities and took place in two phases of an adaptation process, functional stress and resistivity.

The enterosorbent noolit (representing a mineral matrix base with immobilized lithium and silicon compounds) significantly affects the psychoemotional state of mice with depression model induced by prolonged social emotional stress. Noolit administration produces a pronounced anxiolytic and antidepressant effect and reduced the level of behavioral deficiency in the test animals.

Morphological changes in inguinal lymph nodes, lymphatic collector and subcutaneous space were studied up in patients with the lower extremities lymphoedema. While the lower extremities lymphoedema occurs in inguinal lymph nodes the connective tissues spreading in two variants is observed. In the first one fibroblasts and collagen fibres appears in medullar substance (chordae medullaris and medullar sinuses) and in the second the sclerosis process begins from cortical plateau and paracortical zone. It is expedient to include the intraarterial infusion of the xenospleen preparations in complex of treatment of patients with initial stage of the lower extremities lymphoedema, especially in the absence of possibility to proceed with microsurgical intervention and the erysipelas presence in anamnesis.

In conditions of exotoxicosis arising after the effect of 2,4-dichlorphenoxyacetic acid cytoplasmic cells of littoral cells of marginal and medullary sinuses undergo alike changes and their cell organelles (rough endoplasmic reticulum, Golgi complex, micropinocytotic vesicles and mitochondria) mass is reduced. These changes are more pronounced in littoral cells of marginal sinus when the dos under the effect of 4 permissible doses of the poison. Intensity of intracellular structures reaction to the toxicant action depends on the cell localization on the lymph passage insid within the lymph node (marginal or medullar sinuses). Dystrophic changes in sinus lining cells so as the speed and character of regenerative processes depend on the dose and time of action of the agent.

In conditions of experimental inflammation of internal sexual organs in female rats fast and adequate reorganization of its lymphatic bed was found. In the nidus of inflammation sufficient drainage of tissues was retained. Loose and widened sinuses of ileal lymph nodes provided sufficient intranodal lymphodynamics. Formation of additional barrier composed of lymphoid cells was detected in paravaginal fat. Reduction of the speed of lymph flow within lymphangions promoted adequate conveyance of toxic lymph to nodes and its further processing. Mobilization of all links of lymphatic barrier resulted in its maximum activation and self recovery by d 14.

Adsorption of lymphocytes on the sorbents in correction of inflammatory lesions has significant clinical perspectives as the cells and active biological substances they secrete function actively in inflamed tissues acting in the site of its application: every cell adsorbs and inactivates foreign substances, every cytokin affects certain target cells. The products of these cells functioning and dissociation as well as the products of immune system reaction to them remain on the sorbent and are eliminated together with granules during bandaging or by the end of the treatment thus do not entering the organism. Lymphocytic monolayer on the sorbent does not prevent its specific action in pathologic nidus. In this case sorbent does not only drain the tissue duplicating certain primitive non specific functions of regional lymph node (barrier, filtrating, transport, draining and protective functions) but also performs certain highly specialized functions of immunocompetent organs--selective adsorption and inactivation of antigenic substances. It is reasonable to use sorbents for adsorbing lymphocytes in kapron containers which exclude the preparation leak into wounds and cavities and act as a filter preventing fast inactivation of the preparation by large fragments of tissue detritus.

Popliteal lymph nodes of male Wistar rats were studied in scanning regime of electron microscope. On the base of the data obtained it is concluded that on the lymph node surface and in the thickness of a capsule afferent lymphatic vessels branch into thin rami supplied with valves from the inside of the capsule in the site of falling into marginal sinus. Valvular apparatus found obviously gives possibility to regulate lymph flow in the lymph node.

Anterior mediastinal and popliteal lymph nodes were studied morphologically and cytologically in male Wistar line rats in an acute period of experimental ischemia resulting from ligation of the left coronary artery. Three stages of structural-functional changes were demonstrated. In first stage increase of cortical substance square, widening of intermediate sinuses and macrophage number increase in all lymph node zones were observed in both groups after ligation of the artery. Second stage (day III of the ischemia) is characterized with the accumulation of plasmatic series cells and reaction of blast transformation in lymph node zones. In third stage (day 7 of the ischemia) restoration of medullar sinuses square up to the control values and even certain increase of the latter were observed. Morphofunctional changes in an acute period of the experimental ischemia of myocardium depend on the lymph node functional specialization and they are greater expressed in mediastinal lymph nodes of the heart region. It was suggested that in an acute period of ischemia of myocardium lymph nodes influence the quantity and cellular content of the passing lymph.

Pharmacokinetics of water and liposomal suspensions of lipophilic antibiotic rifampicin introduced intragastrically through a tube was studied in experiments on Wistar rats. After administration of water suspension rifampicin concentration reached its peak in all the tissues in 3 hours, lung concentration being 1.6 and 1.9 times higher than blood one. After liposomal suspension administration lymphatic rifampicin concentrations were maximal in 3 hours, while in the lungs and blood they were the highest in 6 hours. It is concluded that oral liposoluble drug enter primarily chyle vessels and via thoracic lymphatic duct directly lesser circulation. Liposomal inclusion of the drug warrants its high concentration in lymphatic system and lung tissue.

The structural and functional responses of lymph nodes to environmental influences have common stereotypic features; however, they can vary with the nature of an influencing factor and the functional specialization of the lymph node. In this view, the morphological and functional status of lymph nodes can be regarded as markers of environmental impact on the lymphatic system. Approaches to correcting blood and lymph circulation have been developed via combined exposure of the body's internal environment to sorbent therapy, balneological procedures at the Siberian resorts, biological flavonoids, and derivatives of Siberian raw plant materials.

The effects of benzpyrene (BP) were studied in 32 male Wistar rats. Treatment of intact mature animals with benzpyrene causes transformations of hepatocytes. Antenatal treatment with BP initiates a complex of compensatory-adaptational reactions in the liver of progeny and the effect retains at the postnatal period. The combined ante- and postnatal administration of the toxic drug makes the liver prepared to liquidate the effect of the pathogenic action with the help of a complex of compensatory mechanisms with qualitative changes in cell metabolism.

We studied transportation of the colloidal gold labelled albumin 0.5-24 hours after intraabdominal administration of the tracer in normal rabbits and rabbits with experimental diffuse peritonitis (total 24 rabbits). Evacuation of foreign protein goes through the mesothelial stomata to the lymphatic vessels of diaphragm and further to the mediastinal lymph nodes. Sufficient amount of the tracer was captured by the phagocytes inside the lymph collectors. In case of peritonitis reticular cells of the lymph node displayed decreased capture of the tracer. This fact can be attributed to obstacles in the evacuation of the tracer from peritoneum and decreased phagocytic capacity of the reticular cells.

Electrical impedance of white rats heart muscle of wistar population was measured in different terms of experimental myocardial infarction. Results of electroimpedansometry reflect in full extent structural changes, taking place in a heart muscle. General tendency of animal and human healing processes was found and it was confirmed, that infarction affects the whole heart muscle.

The microanatomic organization of iliac lymph nodes was studied in 24 pregnant Wistar rats (pregnancy term 21 days) after simulation of acute hemorrhage in them. A considerable decrease of a relative area occupied by a marginal sinus was revealed. This shows transport functional changes of lymph nodes in pregnancy complicated by hemorrhage.

Under study was the influence of polyphenolic complexes of great burnet and venoruton upon the thymus, spleen, iliac lymph nodes of the uterus area in experimental phlebo-occlusion syndrome of pregnant rats. The data obtained show the changes of the drainage function of the lymphatic system under the influence of the drugs under study, certain reaction of T- and B- dependent zones of the central (thymus) and peripheral lymphoid organs. The structural-functional shifts had positive effects upon the fetus state. The action of polyphenols of great burnet is more effective as compared with venoruton.

The peripheral blood and central lymph of rats under experimental myocardial infarction was studied by means of light microscopy and electric conductivity measurement. Both hypertensive rats and animals 3 days after myocardial infarction had similar quantity of neutrophils in peripheral blood. Lymph cells count of hypertensive rats by middle lymphocytes is similar to the animals 1 day after myocardial infarction. The correlation between lymph and blood electric conductivity and its cell composition was noted.

Regional lymphatic bed in local application of mineral sorbent SUMS-2p in 80 white noninbred rats with experimental generalized purulent peritonitis is studied with the use of indirect intravital lympho-roentgenography. The correlation between lympho-dynamics and generalized purulent peritonitis stage was observed. It is shown that the peritoneo-sorption with the mineral sorbent SUMS-2p led to early restoration of lympho-drainage.

Polyphenol preparation of Poterium sanguisorba was tried for the treatment of experimental pregnancy abnormalities. The teratogenic and embryotoxic effects of the preparation administered in a dose of 0.75 LD50 were studied. The therapeutic doses of the drug are characterized by an immunostimulating effect on the mother and help correct the fetoplacental circulation and improve the fetal morphofunctional status.

The density of adrenergic innervation and relative content of catecholamines were investigated in rat lymphoid organs under different type of benzpyrene treatment. It was found that both ante- and postnatal influence of toxicant leads to a decrease of neurotransmitter providing of the thymus, spleen, mesenterial, iliac and popliteal lymph nodes. On the contrary, when mixed ante- and postnatal benzpyrene influence has place, the adrenergic innervation density and relative content of catecholamines are increased. We suppose that benzpyrene treatment of pregnant animals has specific "training" effect for monoaminergic systems of foetus and causes the increase of neurotransmitter providing of immunocompetent organs in conditions of repeat body and toxicant meeting.

In the lymphoid tissue of the iliac lymph node at an aseptic inflammation in the uterus the greatest changes have been revealed in 48 h from the moment, when the foreign body has been introduced. They are manifested at the tissue level (increasing content of macrophages, lymphoblasts, large lymphocytes, plasmoblasts, immature plasmocytes, mast cells, neutrophils), as well as at the organic level (increasing amount of secondary lymph noduli, increasing area of the paracortical zone, decreasing area of the cortical plateau, of the medullary intermediate sinus, medullary cords). Use of carbomineral sorbents ensures correction of the inflammation; this is demonstrated as reduction of reactive changes in the regional lymph node.

Morphometrical investigation of the blood microcirculatory bed has been performed using the material from nonpregnant rats. Changes in volumetric density of the arterial and venous parts of the microcirculatory bed in the ovary and uterine tube after application of the spherical carbonate-mineral sorbent (SUMS-1) demonstrate a corregating effect of the sorption applied.

We studied the volume compactness of the arterial, capillary and venous parts of the microcirculation channel after 24, 48, 72 and 96 hours of the aseptic inflammation and after local application of the carbon-mineral sorbents in the rat's uterus. The local sorption decreased the reaction of the inflammation in the endo- and myometrium.

Using certain histological and morphometrical methods, cytoarchitectonics of T- and B-zones in the iliac lymph nodes have been studied with a simultaneous embryometry at a physiological pregnancy and under conditions of immunomodulators (IM) administration. The degree of influence of IM changes in the raw polysaccharide++-conjugate-polyelectrolite. Mass of the lymph nodes studied under effect of polyelectrolite becomes greater. Polyelectrolite and conjugate stimulate essentially the hormonal link of immunity and activate the system of mononuclear phagocytes. Morphofunctional state of the iliac lymph node changes more considerably at polyelectrolite administration and somewhat less--at conjugate, with the greatest degree in pregnant mice, in comparison with nonpregnant ones. The IM produce hypertrophy of the lymph node, making a stimulating effect in lymphatic nodules++, paracortical zone cortical plateau, medullary cords, medullary intermediate sinus, as well as in cellular reactions (blast transformation++, amount of macrophages and plasma cells having various degree of differentiation, bi- and multinuclearity). Parallelizm between rearrangement degree of the iliac lymph node, administration of the synthetic IM and growth of the fetus mass has been revealed. This stresses the volume of reserved plastic properties of the lymph node and possibility to make longer the period of its greatest activity up to termination of pregnancy when IM are introduced. Pregnancy is a sensibilizing factor, which intensifies (or prolongates) the reaction of T- and B-zones in the lymph node and its cell composition. IM, altering the maternal immunological status, produce certain changes in the fetus mass.

Interrelations of the blood and lymphatic systems of the uterus have been examined in rats at pregnancy complicated with the ++phlebo-occlusive syndrome. Blood stream impediment in the caudal vena cava results in increasing diameter of the arterioles, capillaries and venules of the endo- and myometrium. Certain disturbances of blood circulation in the uterus at the ++phlebo-cclusive syndrome in the pregnancy animals, as a rule, reflect in the uterine lymph outflow; this is demonstrated as dilatation and deformity of the lymphatic vessels and capillaries, appearance of protrusions of the lymphatic vessels wall. There is a definite co-ordination in the reaction to the caudal vena cava occlusion in the intra-, ++extra-organic uterine lymphatic bed and in its regional lymph nodes, manifested as the following morphological signs: decreasing relative volume, that the lymphoid tissue occupies and increasing relative volume of the cortical and medullary intermediate sinuses.

By the morphometric method the microanatomical organization of the popliteal and kidney lymph nodes of the type Vi was studied in venous congestion. In the first experimental series (lymph nodes localize in venous congestion area) the venous congestion in the popliteal lymph nodes was created by the ligature of caudal vena cava. In the second experimental series (lymph nodes, which clean the venous congestion area--the kidney vena was tied up. The small and short time increase of the marginal sinus volume and hypertrophy of the medullary cords, which seemed about medullary substance B-zone stimulation were characteristically for the lymph nodes, localize in the venous congestion area. The sharp increase of the marginal sinus volume during the long experimental time and paracortical T-zone hyperplasia were characteristically for the lymph nodes, which clean the venous congestion area.

C57B1/6 inbred mice were placed in hypomagnetic condition during 14 days constantly. Degree of relaxation of geomagnetic field was 10(4). The increase of the number of eosinophil granulocytes was discovered in peripheral blood of mice. Measures of circadian rhythms of blood's absolute lymphocytosis, absolute number of cells in bone marrow, thymus, spleen and inguinal lymph nodes were safe. Adaptation of lymphoid system to hypomagnetic condition was manifested by desynchronization of circadian rhythmicity on the basis of different sensitivity of lymphoid organs, that realized in strengthening of ultradian rhythms with periods of 15 hours. There are indirect data, that show the increase of speed and/or volume of recirculation of lymphoid cells.

Ultrastructure of endothelium in the rat popliteal lymph nodes has been studied. The cross section area of the capillary arterial part is 29.9 +/- 1.0, that of the venous part -- 91.2 +/- 1.6, the luminal cross section of the arterial part is 4.90 +/- 0,23, that of the venous part -- 46.8 +/- 1.1 mcm2. Nucleous-cytoplasmic ratio in the endotheliocytes of the arterial part is 1.50 +/- 0.06, that of the venous part -- 2.10 +/- 0.13. The number of microvesicles per 1 mcm of the profile length in the section of the basal surface in a plasmolemma is 1.13 +/- 0.07 both in the arterial and venous parts of the capillary, that of the luminal surface -- 1.35 +/- 0.07 for the arterial part and 0.48 +/- 0.03 for the venous part. The number of free microvessels per 1 mcm2 of the cytoplasmic cross section area is also greater for the arterial part (9.6 +/- 0.8 vs. 7.3 +/- 0.4 in the venous part). Numerical density of free ribosomes in endotheliocytes of the arterial part is 62 +/- 6, in the venous part -- 47 +/- 5 per 1 mcm2 of the cytoplasmic cross section. Numerical density of mitochondria in the venous part is 0.77 +/- 0.11 and in the arterial part -- 0.40 +/- 0.04 per 1 mcm3 of cytoplasm.

Ecological influences, exercised on one the most important homeostatic systems - the lymphatic system - have been investigated extremely insufficiently. Nevertheless, in mechanisms of adaptogenesis interaction of the environmental effects with the lymphoid organs plays a rather essential role. Structural-functional response of the lymph nodes to the environmental effects possesses some features of stereotype, however, the stereotypic response is subjected to modulations in connection with the factor acting and functional specialization of the lymph node. Keeping this in mind, the lymph nodes (their morpho-functional status) can be considered as markers of the environmental pressing to the lymphatic system. When estimating the degree and stage of the phasic morpho-functional changes in the lymph nodes during their adaptation to the environmental influences, it is necessary to take into account the possibility of the environmental (in our case - cooling, chemicals) imprinting, in order to judge on the degree of individual stability of the organism to these effects. The morpho-functional rearrangements in the lymph nodes, under the environmental influences on the animal organism, reflect the dynamics of complex interorganic correlations both within the lymphatic system and at intersystemic level.

A mechanotron 6MX1C was used to study lymphodynamic indices of the dog popliteal lymph nodes after cutting the ischiatic and femoral nerves in the left limb at 1 week, 3 and 5 months. The lymph nodes of the contralateral limb and the lymph nodes from intact dogs were used as controls. It has been demonstrated that denervation causes acceleration of the periods of the filling and emptying of the lymph nodes both in the denervated and contralateral limbs as compared with the initial period. The amplitude of fluctuations under maximal filling of the lymph nodes decreases significantly at the long-term postoperative periods. The lymphodynamic changes seem to be determined by pathomorphological alterations in lymph node tissues.

The littoral cells of the sinuses in the popliteal lymph nodes have been studied in Wistar rats under physiological conditions of hemodynamics and 1 h after ligation of the caudal vena cava. Intercellular clefts (1-4 mcm wide) are demonstrated to exist between the littoral cells of the internal wall of the marginal sinus. Presence of fenestrae in the peripheral thinned areas of cytoplasm is specific for these cells. The diameter of the fenestrae is 60-1,000 nm however, the fenestrae with the diameter up to 100 nm predominate. Lining of the medullar sinuses is also characterized by a high content of fenestrae, the maximal diameter of the fenestrae being the same as in the marginal sinus, although most of the fenestrae have the diameter 50-500 nm. No open intercellular clefts between the littoral cells of the medullar sinuses are revealed. In some cases, penetration of lymphocytes through the lining of the sinuses is observed. Under venous congestion, the diameter and amount of the fenestrae, size and amount of open intercellular clefts in the lining of the lymphatic sinuses increase significantly. This demonstrates its increasing permiability, having an essential importance for compensation of circulatory disturbances in the zone of the venous congestion.

The popliteal and iliac lymph nodes have different regional specialization. The former belong to somatic lymph nodes, while the latter get lymph also from internal organs; this explains certain differences in their structural-functional organization. Some objective quantitative data have been obtained that characterize ultrastructure of blood capillaries in the rat popliteal and iliac lymph nodes under normal conditions of the organism's functioning. They demonstrate essential differences in the level of transendothelial transport and, hence, functional activity of these organs.

Transmission and scanning electron microscopy was used to study the structural organization of the lymph nodes during venous congestion. At the early period (1 h of venous congestion) one could see an increased number of the fenestrated cells in the venous part of the capillary whereas at the later period (after 6 h to 3 days) a rise of the microvesicular transport via endotheliocytes of the arterial part of the capillary and via fenestras of the venous part. Within 7 to 14 days one could see activation of the microvesicular transport via the indicated parts of the capillary. At all the stages of venous congestion the fluid contained by the parenchyma of the lymph node penetrates via fenestras and intercellular fissures to the marginal sinus, while only via fenestra to the cerebral sinuses.

Structural-functional organization of the lymphoid organs and functional state of the adrenals have been studied in animals, subjected to cold in early postnatal period, as well as changes of the parameters mentioned to a short and prolonged cooling in mature rats. For the animals increase in the thymus mass and in reproduction rate of lymphocytes in the thymus, spleen and lymph nodes is specific against the background of high corticosteroid secretion. When the control animals are kept in cold for a long time, after the phase of an acute stress, accompanied with hypercorticism and a pronounced lymphatic effect, during the period of an increased cold stability, the high secretion of glucocorticoid hormones is accompanied with a certain activation of thymus-dependent zones in the peripheral lymphoid organs. In the mature rats, subjected to cold at early ontogenesis both stress-reaction to cooling and rearrangement in the regulatory systems studied does not develop at adaptation to cold.