Ileo-colonic lymph nodes in macaques and pavians of different ages]

Quantitative and qualitative alterations occurring in various structural components of the ileocolonic lymph nodes of Papio hamadryas at the age of 3.5 months and 5 years and Macaca rhesus at the age of 5 years were studied by means of mathematical methods. Cellular composition was counted in every histological preparation per 1,000 cells in cortical plateau, in myelin cords, in follicles with light centers and in follicles without light centers. Part (in %) of every cell variety was determined, as well as correlation of different structural components of the lymph nodes. Construcgion and cytoarchitectonics of the ileocolonic lymph nodes were stated to depend on the age of monkeys and their systematic differences.     

Alteration of the construction and cellular composition of ileo-colonic lymph nodes of rhesus macaques after administration of salmonella vaccine]

In stained histological sections, percentage ratio of areas to different cellular elements in structural components of the ileocolonic lymph nodes was studied in mature Macaca rhesus, normal and after injection of salmonella vaccine. A rather considerable reaction in all structural components and cell composition of the lymph nodes was demonstrated as a response to immunization of the animals. These changes were demonstrated in decreased area occupied by the cortical substance and in increased area occupied by the medullar substance of the lymph node. In the cortical substance, together with decrease in the cortical plateau, total number of folliculi rises with formation of light centers in them. Calculation of cellular elements revealed that in the cortical substance cytopoietic function was inhibited; that was expressed in decreasing mitoses and blast forms in the cells. Most drastic alterations occur in myelin cords of the lymph nodes. Together with increasing area, a considerable reaction of acidophilic leucocytes, premature plasma cells and macrophages is observed. Their number increases notably.     

Cellular composition of structural components of the lymph nodes of rats during rehabilitation after dimethyl sulfate poisoning

By means of microanatomical methods the inferior tracheobronchial lymph nodes have been investigated in 48 Wistar rats in 2 weeks and 3 months after discontinuance of inhalation of dimethylsulfate (DMS) vapours for 2 and 14 days by the animals in concentration 2.0 mg/m3, that is to say during rehabilitation period. Comparison of relative parameters of the structural components areas and cell composition of the lymph nodes has been carried out. During rehabilitation period after DMS inhalation for 2 days the cortical and medullary areas in histological preparations do not essentially differ from corresponding parameters of an acute experiment (2 days, 2.0 mg/m3, without rehabilitation). Amount (%) of cells with mitotic figures in the lymphoid nodules++ increases in 2 weeks and in 3 months. Contents of poorly differentiated cells during rehabilitation periods increase in the cortical plateau, but keeps nearly at the same low level as during the acute experiment in the lymphoid nodules++. In 2 weeks after DMS influence for 14 days, the cortical and medullary area in the histological preparations reach the control levels. In the lymphoid nodules++ a relative amount of reticular, poorly differentiated, mitotically dividing cells increases, and in the medullary cords contents of middle and small lymphocytes become greater in comparison with the acute experiment (14 days, 2.0 mg/m3, without rehabilitation).(ABSTRACT TRUNCATED AT 250 WORDS)     

Morpho-functional status of the lymph nodes of rats during rehabilitation after exposure to vapors of dimethyl sulfate]

By means of histological methods inferior tracheobronchial lymph nodes have been investigated in 48 Wistar rats in 2 weeks and 3 months after cessation of inhalation of DNSV at maximum possible dose (0.1 mg/m3) for 2 and 14 days. Cell composition of the lymph nodes and cross sections of structural components have been compared. The cross section of the cortex decreases, while that of the medulla increases in comparison with corresponding parameters of the acute experiment. In 2 weeks and 3 months after DMSV effect for 2 days the part (%) of poorly differentiated cells and middle lymphocytes increases, while content of plasma cells in the medullary cords decreases. During rehabilitation after DMSV effect for 14 days a low level plateau is noted (as in the acute experiment). However, in lymphoid nodules++ within content of the poorly differentiated cells and middle lymphocytes in the cortical germinative centers in 2 weeks and 3 months the number of the poorly differentiated and reticular cells increases essentially, as well as mitotically dividing cells (in comparison to the acute experiment). In the medullary cords of the lymph nodes after 3 months of rehabilitation content of immature plasma cells is essentially higher than in 2 weeks of rehabilitation and than in the acute experiment. During rehabilitation the level of cells destruction in the lymph nodes noticeably decreases in comparison to the acute experiment.     

Structural changes in popliteal lymph nodes in the graft vs. host reaction to H-Y antigen in male C57BL/6-strain mice

Regional popliteal lymph nodes in intact, control and experimental (I, II, III groups, respectively) have been studied by means of the morphometric method in male C57Bl/6 line mice at the pick of the reaction produced by injection of spleen cells and mesenteric lymph nodes obtained from syngenic females and repeatedly immunized to H-Y antigen (10 animals in each group). Injection of the cell suspensions from the immunized and intact females of the C57Bl/6 mice result nearly in two-fold increasing mass of the regional popliteal node at the expense of enlarged size of all its zones. Changes in cytoarchitectonics of the node structural components result from redistribution of certain cellular elements. The essential changes in the cell composition of the lymph nodes in the II and III male groups are accompanied with an increasing part of the stromal reticular cells. Simultaneously, content of small lymphocytes decreases significantly. In the III group of mice there is a sharp increase in the content of young forms of the lymphoid line cells in all structural components of the node, as well as in eosinophilic granulocytes in medullary cords. In the dark cortical zone of the nodes (III group) there occur tissue basophils (mast cells), that, together with increasing number of acidophilic granulocytes and appearance of neutrophilic cells, demonstrates that there is an inflammatory reaction in the organ studied as a response to the lymphocytic suspension injected. In the experimental group of the animals a complete disappearance of plasma cells is noted in the node cortex, but some increase of their part takes place in the medullary cords.     

Cytoarchitectonics of ileocecal lymph nodes in newborn and sexually mature simians (pavian hamadrils)]

Cell composition of various components (cortical plateau, folliculi and cords) of ileocecal lymph nodes was studied in newborn, 1.5 and 2.5 months of age (2 animals) and in mature (3 animals) monkeys, Papio hamadryas. In histological sections obtained at the level of hilus of the lymph node cellular elements were counted by means of morphometric grid of Glagolev modifoed by S. B. Stefanov. The data obtained were statistically treated. Newborn and mature monkeys have their peculiar cytological profile in every structural component of the lymph node. The lymph nodes in the newborns contain much more reticular cells and young cellular forms (blast forms and large lymphocytes) than mature animals. In the newborns, the number of mitotically deviding cells in the cortical plateau and in folliculi is 6 times and in myelin cords 10 times as great as in mature monkeys. A much greater per cent of plasmatic cells in mature animals suggests their greater immunological activity. Age differences in cell composition of lymph nodes in young and mature monkeys seem to be connected with accumulation of cellular mass and growth of the node in young animals, as well as with general rearrangement of the organism as a whole (in particular with changes in nutrition, intensity of movement, hormonal background).     

Entamoeba histolytica: lymphoreticular changes in gerbils (Meriones unguiculatus) with experimentally induced cecal amebiasis

Antibody responses and changes in the lymphoreticular tissues of gerbils with experimental cecal amebiasis were studied from 5 to 60 days PI. Changes in the cecum consisted of lymphoid follicle hyperplasia and depletion of lymphocytes, followed by follicle atrophy and histiocytosis. Mesenteric lymphadenopathy, and histologic alterations in the lymph nodes paralleled the progressive development of amebic cecal lesions. Early in the infection (5 to 10 days PI) mesenteric lymph nodes showed cortical follicle hyperplasia, blastogenesis in the paracortical areas (PCA) and intense lymphoblast and plasma cell activity in the medullary cords. At 20 to 30 days PI, the cortical follicles, the PCA and the medulla were depleted of lymphocytes and there was histiocytosis throughout the organ. At 60 days PI, lymphocyte repopulation took place in the PCA, and cortical follicles had active germinal centers. Spleen follicles did not increase in number as the infection progressed, but became hyperplastic. Antibody titers to ameba were low throughout the cecal infection but rose whenever amebic metastasis to the liver occurred. The results of this study indicate that lymphocytes from the submucosal lymphoid follicles and the draining lymph nodes may control the pathogenesis of the infection. Lymphoreticular tissue alterations could result from antigenic stimulation and migration of cells to the sites of infection.     

Degree of chromatin activity and the RNA level in lymphocytes of popliteal lymph nodes of dogs after administration of an antigen]

In the experiment performed on 127 dogs by means of cytospectrofluorometric analysis, using fluorochrome acridine orange in dynamics up to 1 year, changes in the level of chromatin activation and RNA content have been studied in lymphocytes of the germinative centers and the crown of lymphoid nodules, in the paracortical zone and medullary cords of the regional and contralateral popliteal lymph nodes, after subcutaneous injection of antigen (BCG vaccine, 0.2 mg/kg) into the lateral area of the foot of the left pelvic extremity. The immune response is accompanied with a periodical increase in the level of chromatin activation and RNA content in populations of lymphocytes in the regional and contralateral popliteal lymph nodes with maximum in 6 h, 3-7 days, 1-3 months after the antigen injection. The intensity of these processes has an unequal level in lymphoid cells of various structural components; it is higher in lymphocytes of the contralateral lymph node.     

Mesenteric lymph nodes in the rat after exposure to hydrocortisone

The construction and cell composition of the cortex and medulla have been morphometrically studied after 1-, 3-, 5-, 7- and 14-aliquot injection of medical doses of hydrocortisone (0.25 mg per 100 g of body mass). The body mass of the animals decreases, as does the size of the mesenteric lymph nodes. The lymphocyto- and immunocytopoietic functions intensify in the medullary cords with a simultaneous inhibition of these processes in the cortical plateau and in the lymphoid noduli. On the 5th and 7th days there is some increase in the section area of the cortex, while that of the medulla decreases. The part of small lymphocytes in these structures grows large. Therefore, it is possible to suppose a definite tendency towards restoration of the structural components within two weeks.     

Role of macrophages in the immune response to soluble protein antigen and in staphylococcal infection]

In experiments on rabbits immunized with soluble protein antigen immune reactions were found to be accompanied by the production of lipofuscin in macrophages. This process was the morphological manifestation of the digestion of antigen by macrophages which thus acquired the ability to migrate in the organ and to form lymphoid follicules in the medullary zone of lymph nodes. The newly formed follicules seem to be the basis of pronounced specific immune response. In staphylococcal bacteriemia the phagocytic activity of macrophages was delayed, thus causing disturbances in lipofuscin production; as a result, the subsequent phases of immune response also lagged somewhat behind in time.     

Cytoarchitectonics of the tracheobronchial lymph nodes in rats exposed to carbon disulfide

Cytoarchitectonics and rearrangement of cellular composition in functionally different zones of the rat tracheobronchial lymph nodes have been studied at a short effect of the industrial carbon disulfide vapour at a maximally admissible concentration (MAC) (1 mg/m3 and 10 mg/m3), as well as after the effect of MAC of carbon disulfide in the inhaled air for 4, 7, 14 days. The inhalation of the carbon disulfide vapours results in certain changes of the cytoarchitectonics of the lymph nodes studied in dependence on concentration and duration of the substance effect in the air inhaled. The effect of the MAC carbon disulfide, when the experiment lasts for 2 days, is accompanied with a decreased lymphocytopoiesis in all the structural components of the node and with a sharp intensification in the number of plasma cells of the medullary cords, that demonstrates local immunocytopoiesis. An opposite picture is noted, when carbon disulfide is applied in an elevated concentration (10 mg/m3)--plasmic reaction is sharply inhibited in the medullary cords, lymphocytopoiesis is noticeably increased, certain signs of allergic reaction are also seen. A prolonged effect of carbon disulfide vapours (up to 14 days) in MAC results in lymphocytopenia of the nodes, in increasing destructive processes and in decreasing cell proliferation. Differences in reaction of the structural components are revealed in the nodes studied at the toxic effect: in the cortical plateau and in the medullary cords suppression of the lymphocytopoietic activity is noted, and in the medullary cords--inhibition of immunocytopoiesis.     

Structure of the arterial bed in human lymph nodes

Blood vessels, that bring blood to various areas of the human superficial inguinal lymph nodes are predominantly arterioles and precapillaries. They are often arranged radially from the hilus to the capsule and from the capsule towards the portal thickening. The arteries and arterioles of the portal and capsular trabeculae reach the paracortical zone, occupying an intermediate position between the medullary cords and the cortex of the lymph node. The arterioles of the paracortical zone, passing between the cortex and the medullary cords, acquire an arcuate appearance. In both directions from them (into central and peripheral areas of the node) precapillaries branch off at a right angle. The cortex is supplied with blood by the arteriolar branches of the paracortical zone and the capsule of the node. The cortical precapillaries branch into capillaries either within the lymphoid nodules, or along their periphery. In the medullary cords those arterioles branch, that get from the portal thickening, portal trabeculae and paracortical zone.     

Cellular composition of various structural zones of the iliac and mesenteric lymph node of pregnant rats

The dynamic of cellular reactions demonstrates certain changes in functional activity of all structures of the node during pregnancy. A similar trend of processes in the iliac (regional for the uterus) and mesenteric lymph nodes has been defined. At early stages of pregnancy, lymph nodule are the most active, this is demonstrated as an increasing portion of lymphoblasts, macrophages and dividing cells. During this period, cell composition of the cortical plateau is relatively stable. For the paracortical zone of the mesenteric lymph nodes a rather significant decrease in the portion of middle lymphocytes and reticular cells is characteristic. There is not any significant change in the relative amount of the cells in the same functional zone of the iliac lymph nodes during the same period of pregnancy. The medullar cords demonstrate an increasing number of blast forms and young plasmocytes. However, as the pregnancy develops, the structure of the paracortical zone undergoes an essential change--progressively increases the portion of lymphoblasts and large lymphocytes. The blastic reaction in the mesenteric lymph nodes is proved to depend, to some extent, on that in the iliac lymph nodes of the same animal. Mature plasma cells become the dominating cellular element in the medullary cords. At the end of the pregnancy a relative amount of the reticular cells increases in all structural zones of the node.     

Features of the structure of the regional lymph nodes of the duodenum in monkeys

By means of morphometric methods, duodenal regional lymph nodes were studied in rhesus and lapunder macaques. It was demonstrated that in monkeys the connective tissue framework, cortical plateau, medullary substance, cortical substance, sinuses and follicles are expressed differently. Cellular elements in the lymph nodes analysed in the monkeys subjected to a comparative investigation demonstrated their uneven distribution in the same structural components. Small lymphocytes were predominate cellular elements. There were rather essential differences in the number of plasmic cells, mitotically dividing cells, acidophilic granulocytes, mast cells and macrophages. Certain species differences were demonstrated to exist both in structure and cell composition of the lymph nodes that seemed to depend on some local peculiarities of immunogenic reactions.     

Morphocytochemical reaction of the lymph nodes in dogs to the administration of lysozyme

By means of morphological, morphometrical and histochemical methods pelvic and tracheobronchial lymph nodes have been studied in dogs and concentration of lysozyme has been estimated in blood serum, in lymph and the lymph nodes after a single intramuscular injection of lysozyme (2 mg/kg of body mass). In the material investigated total concentration of lysozyme reaches its maximal values in 6 h after injection, then it gradually decreases and in 48 h reaches its control level. Morphometrically changes in cell composition are revealed predominantly of immune-competent cells in T- and B-dependent zones of the lymph nodes. Thus, the volumetric part of lymphoblasts in the germinative centers of the lymphoid nodules reaches its maximal indices by 48 h after lysozyme injection, while plasmatization of the paracortical zone and of medullary cords increases up to the 7th day. By the 14th day the volumetric part of lymphoblasts, immunoblasts and plasmocytes decreases gradually, and in 21 days after injection of the drug contents of the blast forms of the cells in the structural-functional zones of the lymph nodes does not differ from that in the control. The data obtained demonstrate the immunomorphological rearrangement of the lymph nodes in response to the exogenic lysozyme administration.     

Regional graft vs host reaction to H-Y antigen (immunological mechanisms)

Structural changes in the regional popliteal lymph nodes have been studied in C57Bl/6 male mice at the peak of the reaction "graft-versus-host" to H-Y antigen. Morphological and morphometrical investigations have been carried out in three groups of males (10 animals in each group). The first group includes intact animals (the first control group). To the males of the second group (the second control group) lymphoid cells are inoculated from intact C57Bl/6 females. To the males of the third group (experimental group) lymphoid cells are inoculated from H-Y antigen immunized C57Bl/6 females (anti-H-Y effector lymphocytes). The popliteal lymph nodes of the male mice from the third group twice increase in their size comparing to those in the control (the first and the second groups). Miotic activity increases in them 4.5 times, amount of cellular blast forms in medullary cords--4 times and 10 times--in the light zone of the cortical substance. Ratio of macrophages and eosinophils in structural components of the lymph nodes studied changes; this is, evidently, connected with massive destructive progresses, that take place in the lymph nodes of the animals from the third group. The results of the morphological investigations are in agreement with the hypothesis suggested, explaining the mechanism of development of the regional reaction "graft-versus-host" to H-Y antigen, basing on idiotype-antiidiotype interaction (the idiotypic network in the immune system).     

Lymphocyte migration in syngeneic lymph node implants

Lymph nodes implanted subcutaneously to syngeneic recipients were shown to regenerate after mass cell destruction. Regenerated lymphoid tissue has a resemblance to the cortical zone of intact lymph nodes. Microenvironment of regenerated lymphoid tissue provides homing of lymphocytes. However, migration of 51Cr-labelled lymphocytes to implants declined drastically, as compared to lymphocyte migration to intact lymph nodes. Attenuation of proliferative activity and the data of morphological analysis indicate a more prolonged retention of lymphocytes in implanted lymph nodes. The results obtained could be attributable to only partial recovery of sinus and vessel systems regulating the inflow and outflow of lymphocytes in lymph nodes.     

Age and changes in the splenic lymphoid tissue of germ-free rats during the postnatal period of ontogenesis]

In germfree rats the splenic lymphopoiesis is not demonstrated by the investigation to be suppressed, and lymphoid follicules undergo age changes. Up to 15 days, periarterial zone of T-lymphocytes, responsible for cell immunity, is determined, and by the 30th day, as in control animals, peripheral zone of B-lymphocytes, responsible for hormonal immunity, is distinctly observed. In 4-month-old germfree animals, a large amount of free iron crystals is detected in the spleen, while in the organ of control animals its amount is still small. In 10-month-old germfree rats, with the appearance of reactive centers, the zone of B-lymphocytes widens in lymphoid follicules and iron crystals integrate in the red pulp. Lymphopoiesis in the spleen of the germfree rats seems to be maintained by certain local conditions which are connected with increased haemolytic function of the organ. This produces a discharge of a large amount of the products of erythrocytosis which, like autoantigens, stimulate lymphopoiesis in the spleen even when microflora is absent in the organism, while lymphopoiesis in lymph nodes in germfree animals is sharply inhibited.     

Structural and functional characteristics of the lower tracheobronchial lymph nodes in the rat after administration of dimethyl sulfate

By means of microanatomical methods the inferior tracheobronchial lymph nodes in 36 Wistar rats have been investigated, when the animals have been subjected to the effect of dimethylsulfate (DMS) vapors. The effect of the substance in doses 0.1 and 2.0 mg/m3 for 2 and 14 days has been studied. Comparison of relative parameters of the structural components areas and the cytological profile of the lymph nodes has been performed. DMS effects for 2 and 14 days in the maximal tolerance concentration (MTC) results in increasing area of the connective tissue stroma and the cortical substance, in comparison with the control, as well as in decreasing area of the medulla substance. At the contact with DMS for 2 days (at a corresponding MTC) certain changes of the nodular cytological profile are noted. They demonstrate that to the given time of the experiment the adaptive processes in the lymph nodes have no time to develop completely. DMS effect for 14 days in the same concentration produces an increased destruction of cellular elements and inhibits the plasmocellular reaction intensity (in comparison to the control and the experiment for 2 days). DMS maximal concentration (2.0 mg/m3) results in decreasing area of the lymphoid noduli with germinative centers. Intensity of mitotic processes decreases and autoimmune processes develop.     

Structure of the thymus gland, spleen and inguinal lymph nodes of albino rats after immunologic correction during the process of adaptation to physical exercise]

In the experiment performed on 70 noninbred white male rats by means of histological and morphometric techniques construction and cell composition of the thymus, spleen and inguinal lymph nodes have been studied under the influence of systematic physical (swimming) loads. They have been applied under conditions of a pharmacological correction (administration of leacadin) and without it. In the animals not given leacadin, the physical loads result in decrease of the immune function in all the organs investigated. This is evident from decreasing size of the thymus, outgrowth of adipose tissue in it, drop in amount of lymphoid nodules++ in the spleen, decline of contents of lymphocytes in all the organs, and in the cords of the inguinal lymph nodes--decline of plasma cells. Application of leacadin prevents appearance of unfavourable changes.