Myocytes of the inguinal lymph nodes

Owing to the method for making total plane preparations of the capsule after A. V. Borisov, it is possible not only to prove presence of myocytes in the capsule and in the trabeculae of the inguinal lymph nodes in the man and rat, but to open out general regularities of their distribution and orientation. In the capsule areas, corresponding to the places, where the lymph nodules are adjacent to (zone A), the number of myocytes is the least. They are oriented in various directions and are in close contact with each other (fascicular-reticulate principle of distribution of myocytes). In the capsule areas, surrounding A zones (named B zones) the myocytes are situated in tight layers and have circulatory orientation. At the place where the afferent lymphatic vessel gets into the capsule, precapsular lymphangion makes an infundibular dilatation and its myocytes along the sloping spiral get into the capsule, where they are arranged circulatory and form a muscular "constrictor". While studying ultrastructure of myocytes in the rat inguinal lymph nodes, it has been found out that their structure is typical for the smooth muscle cells. There are numerous myo-myocytic contacts of nexus type, that unite the myocytes of the node into a single functional complex.     

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.     

Structural organization of mesenteric lymph nodes in postnatal development of the Baikal seal, <Emphasis Type="Italic">Pusa sibirica</Emphasis> Gmel

Structural organization of mesenteric lymph nodes in the Baikal seal has been studied with regard to its age-dependent changes. It has been shown that the relative area of connective tissue structures (the capsule and trabeculae) increases during postnatal development, while the areas of the cortex and medulla decrease. The proportions of secondary lymph nodes and paracortical zone in the cortex become smaller, with the corticomedullary index tending to decrease with age. These phenomena indicate that mesenteric lymph nodes undergo regression during postnatal ontogeny, with their lymphopoietic function being attenuated. Lower values of the corticomedullary index in Baikal seal pups aged 1 month to 4 years are apparently explained by a decrease in the proportion of cortex substance related to the enhancement of the motor function of lymph nodes.     

Histological and enzyme histochemical investigation of the hemal nodes of the hair goat

We investigated the structure of the hemal node in six healthy hair goats using histological and enzyme histochemical methods. After processing, tissue sections were stained with Crossman's trichrome, Gordon-Sweet's silver and Pappenheim's panoptic stains. Alpha-naphthyl acetate esterase (ANAE) and acid phosphatase (ACP-ase) were demonstrated in frozen sections. Hemal nodes were encapsulated by connective tissue and few smooth muscle cells. Several trabeculae originated from the capsule and extended into the hemal node. A subcapsular sinus was present beneath the capsule and was continuous with the deeper sinuses. Subcapsular and deep sinuses were filled with erythrocytes. The parenchyma consisted of lymphoid follicles, diffuse interfollicular lymphocytes and irregular wide lymphoid cords. Cortical and medullary regions were not distinct. ANAE (+) and ACP-ase (+) cells were located mainly in the germinal centers of the lymphoid follicles and also were scattered equally in the interfollicular region and lymphoid cords. Monocytes, macrophages and reticular cells displayed a diffuse positive reaction, whereas localized granular positivity was observed in lymphocytes. We demonstrated that the general structure of the hair goat hemal nodes is similar to that of other ruminant species.     

Histological and enzyme histochemical investigation of the hemal nodes of the hair goat

Abstract

We investigated the structure of the hemal node in six healthy hair goats using histological and enzyme histochemical methods. After processing, tissue sections were stained with Crossman's trichrome, Gordon-Sweet's silver and Pappenheim's panoptic stains. Alpha-naphthyl acetate esterase (ANAE) and acid phosphatase (ACP-ase) were demonstrated in frozen sections. Hemal nodes were encapsulated by connective tissue and few smooth muscle cells. Several trabeculae originated from the capsule and extended into the hemal node. A subcapsular sinus was present beneath the capsule and was continuous with the deeper sinuses. Subcapsular and deep sinuses were filled with erythrocytes. The parenchyma consisted of lymphoid follicles, diffuse interfollicular lymphocytes and irregular wide lymphoid cords. Cortical and medullary regions were not distinct. ANAE (+) and ACP-ase (+) cells were located mainly in the germinal centers of the lymphoid follicles and also were scattered equally in the interfollicular region and lymphoid cords. Monocytes, macrophages and reticular cells displayed a diffuse positive reaction, whereas localized granular positivity was observed in lymphocytes. We demonstrated that the general structure of the hair goat hemal nodes is similar to that of other ruminant species.     

Langerhans cells in the lymph node: mirror section and immunoelectron microscopic studies

Cells immunostained with antibodies against both OKT-6 and S-100 protein were observed only in superficial and hilar lymph nodes draining tissues with predominantly squamous epithelia. In contrast, in mesenteric lymph nodes and the spleen, only S-100 protein-positive, but OKT-6-negative cells were found. We suspect that the S-100 and OKT-6-positive cells might be Langerhans cells (LC) and the S-100-positive, OKT-6-negative cells, interdigitating reticulum cells (IDC). We further postulate that the LC in superficial and hilar lymph nodes might migrate from squamous epithelia, with which contact is required for the formation of Birbeck granules.     

SEM and TEM study of caprine superficial lymph nodes

The splenic capsule was characteristic, having dense connective tissue. Smooth muscle cells and unmyelinated nerve fibers were observed. Smooth muscle cells were found to be independent of blood vessels in both the capsule and trabeculae. Littoral cells separated the capsule from the subcapsular sinus. Highly branched reticular cells were associated with the sinuses. The cellular components (large and small lymphocytes, plasma and mast cells, and macrophages) of the cortex and medulla were observed and described. No Golgi apparatus was observed in small lymphocytes and two surface types (rough and smooth) were observed on lymphocytes. Russell bodies were not observed in plasma cells. The paracortical postcapillary venule had cuboidal endothelium with microvilli. Two shapes of lymphocytes were seen associated with the endothelium of postcapillary venules.     

Differentiation of Langerhans Cells from Interdigitating Cells Using CD1a and S-100 Protein Antibodies

The present study shows that Langerhans cells can be differentiated from Interdigitating cells at the light microscopic level. Superficial lymph nodes and skin taken from necropsies and the lymph nodes of dermatopathic lymphadenopathy (DPL) were used for this experiment. Sections of lymph node and skin were embedded using the acetone, methyl benzoate and xylene (AMeX) method and dendritic cells were immunostained with anti S-100 protein antibody (S-100, and OKT-6 (CD1a) using the restaining method. Langerhans cells in the skin were positive for both CD1a and S-100. Dendritic cells positive for both CD1a and S-100, and dendritic cells positive for S-100, but not for CD1a were observed in superficial lymph nodes. In normal superficial lymph nodes, there were more interdigitating cells than Langerhans cells. The majority of the dendritic cells in the DPL were Langerhans cells. We conclude that the S-100 and CD1a positive cells are Langerhans cells, and the S-100 positive-CD1a negative cells are interdigitating cells.     

Differentiation of Langerhans Cells from Interdigitating Cells Using CD1a and S-100 Protein Antibodies

The present study shows that Langerhans cells can be differentiated from Interdigitating cells at the light microscopic level. Superficial lymph nodes and skin taken from necropsies and the lymph nodes of dermatopathic lymphadenopathy (DPL) were used for this experiment. Sections of lymph node and skin were embedded using the acetone, methyl benzoate and xylene (AMeX) method and dendritic cells were immunostained with anti S-100 protein antibody (S-100, and OKT-6 (CD1a) using the restaining method. Langerhans cells in the skin were positive for both CD1a and S-100. Dendritic cells positive for both CD1a and S-100, and dendritic cells positive for S-100, but not for CD1a were observed in superficial lymph nodes. In normal superficial lymph nodes, there were more interdigitating cells than Langerhans cells. The majority of the dendritic cells in the DPL were Langerhans cells. We conclude that the S-100 and CD1a positive cells are Langerhans cells, and the S-100 positive-CD1a negative cells are interdigitating cells.     

Langerhans cells in the lymph node: mirror section and immunoelectron microscopic studies.

Cells immunostained with antibodies against both OKT-6 and S-100 protein were observed only in superficial and hilar lymph nodes draining tissues with predominantly squamous epithelia. In contrast, in mesenteric lymph nodes and the spleen, only S-100 protein-positive, but OKT-6-negative cells were found. We suspect that the S-100 and OKT-6-positive cells might be Langerhans cells (LC) and the S-100-positive, OKT-6-negative cells, interdigitating reticulum cells (IDC). We further postulate that the LC in superficial and hilar lymph nodes might migrate from squamous epithelia, with which contact is required for the formation of Birbeck granules.     

Production and characterization of a monoclonal antibody to human type III collagen

Human type III collagen from placenta was isolated and purified for use as an immunogen. A monoclonal antibody was produced which specifically recognizes epitopes unique to type III collagen. The specificity of the antibody was determined by inhibition ELISA, an immunoblot assay, and by immunoprecipitation. Results indicated that the monoclonal antibody recognized only the alpha 1(III) polypeptide chains and did not crossreact with type I, IV, or V collagen. The monoclonal antibody was also used for immunohistochemical localization of type III collagen in tissue sections of human placenta, bovine spleen, and lymph node. In placenta, both large and small blood vessels showed pronounced staining of the tunica media, which contains largely smooth muscle cells, known to synthesize type III collagen. In contrast, the intimal areas and endothelial cells showed no staining with the antibody. In the placental villi, staining was limited to the villous core, where fine fibrillar structures showed strong staining. In lymph nodes, the capsule and pericapsular adipose cells were surrounded by a covering of type III collagen. Within the parenchyma of the node, staining was localized to a branching, reticular array of fine fibers. In the spleen, staining was pronounced in the capsule, splenic trabeculae, and white pulp, where blood vessel staining was especially prominent. The red pulp and splenic sinuses contain little or no type III collagen. The fine network-like or reticular staining pattern found in the lymph node parenchyma is consistent with the staining pattern of the protein reticulin, and suggests that type III collagen may be closely associated with reticulin in certain tissues. Since the role of type III in tissues is unclear, this reagent will be useful in providing new information in this regard.     

Mast cell types in the lymph nodes of the opossum Didelphis albiventris (Marsupialia,Didelphidae)

Summary Using histological and histochemical techniques, we have found a unique population of mast cells in the lymphatic sinuses of lymph nodes from different anatomical regions of the opossum. The lymphatic-sinus mast cells of the medullary sinuses were numerous, and could be easily distinguished from the connective-tissue mast cells of the dermis and lymph node capsule by their larger size and their enlarged cytoplasmic granules that were also more heterogeneous in shape and staining properties.     

Microanatomy of the lung parenchyma of a tegu lizard Tupinambis nigropunctatus

The combined techniques of light microscopy, scanning (SEM) and transmission (TEM) electron microscopy were used for the first time to study the structure of unicameral lungs of a Tegu lizard (Tupinambis nigropunctatus). The lungs are prolate spheroid bags with blood supplied by superficial branches of a dorsal pulmonary artery and returned by diffuse, more deeply located veins. The primary bronchus enters the medial aspect near the apex of the lung. The lung wall is composed of trabeculae: (1) arranged in a faviform pattern, (2) forming individual faveoli (gas exchange chambers) which appear deepest in the cranial one-half of the lung, (3) all of which have a smooth muscle core overlain by either a ciliated or nonciliated epithelium. A ciliated epithelium lines the luminal surfaces of the large primary trabeculae and parts of smaller secondary trabeculae; it is composed of cone-shaped cells with ciliated-microvillous surfaces, and of columnar serous secreting cells. Nonciliated epithelium covers the luminal surface of portions of some secondary trabeculae, abluminal surfaces of primary and secondary trabeculae and all surfaces of the small tertiary trabeculae forming the faveoli. The nonciliated epithelium overlies an extensive superficial capillary network. The blood-gas barrier (0.7-1.0 μm thick) is composed of a thin cytoplasmic flange of Type I pneumonocytes, a thick homogeneous basal lamina and an attenuated endothelial cytoplasm. Numerous surfactant-producing Type II pneumonocytes are closely associated with the Type I pneumonocytes. The nonrespiratory ciliated epithelium may function in humidification of air and clearing of the lungs.     

Macrophage-lymphocyte clusters in lymph nodes: a possible substrate for cellular interactions in the immune response.

The lumens of the lymphatic sinuses in lymph nodes are traversed by fibrocellular trabeculae. Joined to these trabeculae were macrophages, which formed cell clusters with lymphocytes. It is proposed, based on structural similarities, that these cell clusters are the equivalent in vivo to those seen during primary and secondary immune responses in vitro. These intraluminal macrophages were located in the path of lymph-borne antigen, as well as in the path of newly formed and recirculating lymphocytes in sinuses. This would facilitate the possible interaction between macrophage-associated antigen and antigen-reactive lymphoid cells. The attachment of numerous lymphocytes to the surfaces of macrophages and the resulting cell clusters also afford increased opportunities for lymphocyte-lymphocyte contact.     

Lymphatic vessels in the capsule of the lymph node

By means of the injection method the lymphatic vessels, running to the lymph nodes of various localization, have been studied. Their architectonics in the lymph node capsule is revealed. In the capsule the afferent vessels make peculiar broom-like formations. They are named terminal arborizations of afferent lymphatic vessels (TAALV). Two types of such arborizations are described: palm-like, peculiar for the somatic type of the lymph nodes, and tree-like, specific for visceral nodes. The TAALV diameter is 15-20 mcm. They come across the nodal capsule, penetrating it obliquely with numerous holes. In the TAALV wall myocytes are revealed. Together with the capsule muscular elements they might play a role of the most important factors in the mechanism of lymph circulation.     

Development and cell phenotypes in primary follicles of foetal sheep lymph nodes

Lymph nodes from sheep foetuses and postnatal lambs were examined to determine the participation of different leucocyte populations in primary follicle formation, with special emphasis on the emergence and subsequent development of follicular dendritic cells during late gestation and early postnatal life. A series of immune and enzyme histochemical markers was used. The first 5′-nucleotidase-positive primary follicles were found at 80 days gestational age (gestation in sheep is 150 days) in superficial cervical lymph nodes. In the last month of gestation the primary follicles possessed follicular dendritic cells, macrophages, dendritic cells, and CD5-positive lymphocytes, in addition to IgM-positive cells. Follicular dendritic cells in primary follicles were found to be ultrastructurally immature. These follicular dendritic cells were characterised by a few, coarse surface projections and many ribosomes attached to the endoplasmic reticulum. A final differentiation to mature follicular dendritic cells was coincident with the postnatal germinal centre reaction. Computer-assisted morphometric analysis demonstrated that the size of 5′-nucleotidase-positive primary follicles in the distal jejunal lymph node, but not in the superficial cervical lymph node, increased significantly during late gestation. It was concluded that stromal cells in primary follicles of foetal sheep lymph nodes were a continuously developing population but that ultrastructural maturity was only achieved in the germinal centres of postnatal lambs.     

Lymphoscintigraphic monitoring of the lower limb lymphatic system response to bone fracture and healing

Closed bone fractures, and torn muscles and tendons are "internal wounds". What kind of reaction do they evoke in the local and systemic immune system? Cellular debris of damaged tissue and extravasated blood cells are removed by scavenger cells. They are transported via lymphatics to the lymph nodes. There elimination of self antigens takes place. Clinically, no enlargement of lymph nodes is observed after closed fractures and soft tissue damage. The question arises whether there is really no enlargement of regional lymph nodes, in other words, no reaction to damaged cell antigens. This question was studied by using lymphoscintigraphy to visualize lymphatics and lymph nodes draining the site of closed bone fracture. The lymphoscintigraphic pictures of two groups of patients, those with a rapid noncomplicated healing of leg fractures, and those with protracted healing and undergoing surgical reconstructions, were evaluated. The surface area of lymphatic pathways and inguinal lymph nodes on the injured and contralateral normal limb were measured. Enlarged superficial lymphatics and inguinal lymph nodes were found in limbs with healed bone fractures, and decreased inguinal lymph nodes and visualization of deep lymphatics and popliteal nodes in the majority of patients with nonhealing fractures. There was a lack of correlation between age of patients, duration of healing, and surgical interventions and the lymphoscintigraphic changes. These findings suggest that the fracture gap tissue is a dominant source of signals to the lymph nodes, releasing cellular and humoral regulatory factors. Taken together, there is a strong immune reaction of lymph node to the fracture, although it cannot be recognized clinically.     

A novel porcine circovirus-like agent p1 is associated with wasting syndromes in pigs

A novel porcine pathogen tentatively named P1, which was obtained from the sera of the pigs exhibiting clinical signs of postweaning multisystemic wasting syndrome (PMWS) experimentally caused the classical clinic signs and pathologic lesions of the disease in pigs by direct in vivo injection with P1 DNA plasmids. Twenty colostrum-fed (CF) pigs that were free of PCV2 and P1 at 1 month of age were randomly designated equally to two groups. Group 1 pigs were each injected with 400 μg of the cloned P1 plasmid DNA into the superficial inguinal lymph nodes and Group 2 were injected with same amount of the empty pSK vector DNA and served as controls. Viremias were positively detected in 8 of 10 P1 infected pigs from 14-21 days post-inoculation (dpi). The 8 infected animals showed pallor of skin and diarrhea. Gross lesions in the pigs euthanized on 35 dpi were similarly characterized by encephalemia, haemorrhage of the bladder mucosa, haemorrhage of the superficial inguinal lymph nodes, lung atrophy and haemorrhage. Histopathological lesions were arteriectasis and telangiectasia of the cavitas subarachnoidealis, interstitial pneumonia, mild atrophy of the cardiac muscle cells, histiocytic hyperplasia of the follicles in the tonsils, and haemorrhage of the inguinal lymph nodes. P1 DNA and antigens were confirmed by PCR and immunohistochemistry in the tissues and organs of the infected pigs, including the pancreas, bladders, testicles/ovaries, brains, lungs and liver. There were no obvious clinical signs and pathological lesions in the control pigs. This study demonstrated that P1 infection is one of the important pathologic agents on pig farms.     

突触体素、S-100蛋白、NSE免疫反应神经纤维在人淋巴结的分布

探讨突触体素、S－100蛋白、NSE免疫反应神经纤维在人淋巴结的分布,为淋巴结的神经免疫相互作用提供形态学资料。应用免疫组织化学ABC法观察人类腹股沟、腋窝、肠系膜、肺等淋巴结40例,10％福尔马林固定,石蜡包埋组织切片。结果显示：突触体素、S－100蛋白、NSE免疫反应神经纤维呈细丝状沿被膜和门部结缔组织小梁及血管进入皮质后主要分布于副皮质区,环境淋巴小结,进一步分支到达髓质。同时在淋巴小结发生中心及副皮质区有S－100蛋白免疫反应阳性细胞。在髓质髓窦内有NSE免疫反应阳性细胞。结论;淋巴结内有突触体素、S－100蛋白、NSE免疫反应神经纤维的支配、并有S－100蛋白、NSE免疫反应阳性细胞,为淋巴结的神经免疫相互作用提供形态学资料。     

Ontogeny of human fetal lymph nodes.

Developing lymph nodes from 30 human embryos and fetuses with crown-rump lengths (CRL) of 18 mm (5.6 wk) to 245 mm (26 wk) were examined by light microscopy. The nodes were embedded in araldite, and the sections examined were approximately 1 mu in thickness. The development of nodes was divided into three stages: 1. the lymphatic plexus and connective tissue invagination (30 mm to 67 mm CRL); 2. the early fetal lymph node (43 mm to ,5 mm CRL); and 3. the late fetal lymph node (CRL greater than 75 mm). The lymphatic plexus was formed by connective tissue invaginations and bridges which divided a lymph sac into a meshwork of channels and spaces. Connective tissue invaginations were endothelially-lined and were surrounded by lymphatic space. Reticular cells, macrophages, and blood vessels were found in these invaginations. Early fetal lymph nodes were formed from invaginations when the cellular density and lymphocyte content increased. The lymphatic space surrounding the early node was the developing subcapsular sinus. With further development the early node became packed with lymphocytes, increasing the cellular density and size of the node. The connective tissue surrounding the subcapsular sinus condensed to form the capsule. Afferent lymphatic vessels pierced the capsule. Capillaries, veins, postcapillary venules, and occasional arteries were found in early and late nodes.