Browsing by Subject "Lymph nodes"

Now showing 1 - 5 of 5
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    Earliest lymphoid colonization of neonatal rat lymph nodes, an antigen-specific process
    (Murcia : F. Hernández, 2001) Sainte-Marie, G.
    The present work studied the little known process of lymphoid cell colonization of neonatal lymph nodes, while considering the nodal site of entry of circulating lymphoid cells and the either random or antigen-specific character of the process. Tissue sections of a mesenteric, cervical and popliteal node from each of 57 rats, aged 4 hours to 3 weeks, were analysed. Observations bear on the relative importance of the implication of the subcapsular sinus versus venules of nodes, and the composition of their emerging lymphoid cell population by determining the proportion of lymphocytes and blast-related cells. At 16-20 hours after birth, cell counts yielded a mean proportion of 84% for blast-related cells which decreased to 18% at 3 weeks. These percentages are compatible with values expected for a selective antigen-specific entry of lymphoid cells in nodes, not with values that would result from a random entry of lymphocytes. Moreover, observations revealed that by far most colonizing cells initially enter nodes carried by the afferent lymph, little via their venules.
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    Ectasias of the subcapsular sinus in lymph nodes of athymic and euthymic rats, a relation to immunodeficiency
    (Murcia : F. Hernández, 1997) Sainte-Marie, G.; Peng, F.S.; Guay, G.
    This paper describes a morphologically unusual feature occurring in lymph nodes of some aged euthymic animals but mostly athymic animals. It initially consists of small alveole-like excrescences of the cortical wall of the subcapsular sinus. With dilatation, an excrescence becomes an ectasia which expands into the cortex. Observations suggest that ectasias enlarge under the influence of an increased pressure of the afferent lymph of a node. Such condition conceivably results from a greater lymph formation due to inflamation of the drained tissue site, combined with an impairment to the flow of lymph from the subcapsular sinus into medullary sinuses. A probable relation of ectasia formation to immunodeficiency is discussed. This fonnation results in the atrophy of the affected lymphoid cell populations of a node which likely contributes to aggravate the deficiency of the immune system.
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    Lymph node hyalinization in elderly Japanese
    (Murcia : F. Hernández, 2003) Taniguchi, I.; Murakami, G.; Sato, A.; Fujiwara, D.; Ichikawa, H.; Yajima, T.; Kohama, G.
    Lymph node hyalinization has been comprehensively investigated using specimens obtained from elderly Japanese and white Americans. Onion-peel lesions and associated meshwork areas were often found in the medullary sinus of the thoracic node (mediastinaltype hyalinization), while eosinophilic, glassy and spotty lesions were consistently seen in B lymphocyte areas of the pelvic node (pelvic-type hyalinization). The mediastinal-type hyalinization was comprised of thin collagen fibrils (ca 50 nm in diameter), whereas the pelvic-type hyalinization had thick fibrils (ca 150 nm in diameter). This difference seemed to be consistent with a difference in composite collagen fibrils of vascular walls between the thoracic and pelvic regions. The pelvic-type hyalinization was often or sometimes seen in other nodes, such as cervical, axillary, abdominal and inguinal nodes, especially in white Americans. The mediastinaltype hyalinization, usually in combination with a sinus filled with anthracotic macrophages, tended to be observed in Japanese more frequently than in white Americans. Anthracosis seemed to be connected to the pathogenesis of the hyalinization. On the other hand, because the lesion was weakly positive for Factor VIII immunohistochemistry and because lesions were located along thin vessels, the pelvic-type hyalinization seemed to originate from vascular degeneration in the nodal cortex. Due to the high incidence and large proportion in total volume of the node, the hyalinization seems to be one of the major events that diminish the nodal filtration function and ruin the node with aging.
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    Morphological hallmarks facilitating distinction of omental milky spots and lymph nodes: an exploratory study on their discriminative capacity
    (Universidad de Murcia, Departamento de Biologia Celular e Histiologia, 2020) Cleypool, Cindy G.J.; Mackaaij, Claire; Schurink, Bernadette; Bleys, Ronald L.A.W.
    Background. Omental milky spots (OMSs) are the primary lymphoid structures of the greater omentum. However, the presence of lymph nodes (LNs) has occasionally been mentioned as well. Understanding which lymphoid structures are present is of significance, especially in gastric tumor metastasis; tumor deposits in omental LNs suggest local lymphatic spread, whereas tumor deposits in OMSs suggest peritoneal spread and hence extensive disease. Since LNs and OMSs share morphological characteristics and OMSs might be wrongly identified as LNs, reliable hallmarks facilitating easy discrimination are needed. Materials and method. A series of microscopic morphological hallmarks unique to LNs were selected as potential candidates and were assessed for their discriminative capacity: 1) capsule, 2) trabeculae, 3) subcapsular sinus, 4) afferent lymphatic vessels, 5) distinct B- and T cell regions, and 6) a layered organization with, from the outside in a capsule, cortex, paracortex, and medulla. These hallmarks were visualized by multiple staining techniques. Results. Hallmarks 1, 2 5 and 6 were shown to be the most efficient as these were consistent and discriminative. They were best visualized by Picrosirius red, smooth muscle actin and a B-cell / T-cell double staining. Conclusion. The presence of a capsule, trabeculae, distinct B- and T-cell regions and a layered organization represent consistent and reliable morphological features which allow to easily distinguish LNs from OMSs, especially when applied in combination.
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    Ultrastructural analysis of HNK-1 + cells in human peripheral blood and lymph nodes
    (Murcia : F. Hernández, 1989) Yuda, Fumiaki; Terashima, Kazuo; Dobashi, Michio; lshikawa, Masakazu; lmai, Yutaka
    HNK-1 positive (HNK-1+) cells in human peripheral blood and lymph nodes were comparatively analysed by means of immunohistochemistry and immunoelectron microscopy. In peripheral blood, the HNK-1' cells were grouped into large granular lymphocytes (LGLs), small lymphocytes and intermediate forms, al1 of which had many fine cytoplasmic processes. Except for smoothsurfaced lymphocytes, they could not be distinguished from helperlinducer T (OKT41Leu3a) cells and suppresssor/cytotoxic T (OKT81Leu2a) cells. In double staining, HNKlfT3- cells and HNK-1+T3+ cells could not be clearly distinguished in terms of morphology, although the former contained many LGLs. The HNK-1+ cells in the lymph nodes accumulated in the light zones of the germinal centers (GCs). These cells were small to medium-sized lymphocytes with few electron-dense granules and exclusively co-expressed helperlinducer T cell antigens (HNK-1+T4+). Their cytoplasmic projections were interwoven with those of the follicular dendritic cells which trap immune complexes for a long duration. These configurations suggesl that HNK-1+T4+ cells in GCs are engaged in an immunological regulation of germinal center cells. On the other hand. large blastic HNK-1+ cells were scattered outside the GCs and some of them were in the process of mitosis. Furthermore, HNKl+ LGL-like cells with a few large electron-dense granules were rarely seen. These observations indicate that the HNK-1+ cells in the lymph nodes may proliferate outside GCs and differentiate into LGLs with a strong natural killer function.