The Experts below are selected from a list of 18 Experts worldwide ranked by ideXlab platform
Poels, Lambert G. - One of the best experts on this subject based on the ideXlab platform.
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Splenic venous sinusoid in red pulp (rat)
2010Co-Authors: Poels, Lambert G.Abstract:Immunoelectron microscopy (gold labeling of heparan sulfate in Lowicryl embedding, using the single chain antibody HS4C3). (1) shows the open lumen of a venous sinusoid filled with few electron-dense erythrocytes and lining cells (2). (3) marks a neutrophilic granulocyte. (4) points to the diapedesis of a lymphocyte through the wall of the sinusoid. The splenic Cords (Cords of Billroth) surround the venous sinusoid and contain many cells such as lymphocytes and macrophages with dense lysosomes, as well as a few electron-dense erythrocytes. Arrows indicate the discontinuous basal lamina surrounding the venous sinusoid as well as the scaffolds of basal lamina material that is reinforced with thin collagen fibrils throughout the splenic cord forming the reticular network of the spleen. The basal lamina (arrows) contains electron-dense particles of heparan sulfate molecules (only visible by enlargement of this image). Glycosaminoglycans e.g. heparan sulfate are generally integrated in scaffolds of basal laminae and are secreted by the lining cells and reticular cells
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Scheme of the spleen (human)
2010Co-Authors: Poels, Lambert G.Abstract:Spleen: A. general diagram; B. adult; C. senium 1. capsule of dense irregular connective tissue with few elastic and smooth muscle fibers (it varies with the species); 2. trabecula (septum); 3. trabecular artery derived from the splenic artery; 4. trabecular vein; 5. when the pulpa artery or central artery leaves the trabecula, it becomes invested within the white pulp by cells forming the periarteriolar lymphoid sheath (PALS) of the white pulp; 6. central artery with periarteriolar lymphatic sheath (PALS); 7. arteriole to the germinal centre of splenic nodule (eccentric from central artery); 8. penicillar arterioles; 9. sheathed capillaries surrounded by macrophages; 10. funnel-like entrance into splenic Cords (Billroth's Cords = reticular tissue); 11. terminal capillary end opens into splenic venous sinusoid; 12. reticular cell ; 13. anastomosing splenic venous sinusoids; 14. pulpa vein The red pulp is formed by the penicillar arteriole; the macrophage-sheathed capillaries; the splenic sinusoids; the reticular cells forming the stroma of the splenic Cords (also known as Cords of Billroth), and all cell types of the circulating blood.; 15/16. the white pulp consists of the periarteriolar lymphatic sheaths (PALS), the central artery, and splenic nodule with germinal centre (16) surrounded by a corona. Background: The central artery gives rise to radiating branches, the radial arterioles, ending in the marginal sinus surrounding the white pulp. Blood from the marginal sinus and the central artery is transported into the penicillar arterioles, which end in a capillary network surrounded by macrophages (macrophage-sheathed capillaries). With ageing the spleen decreases in volume and quite a lot of splenic nodules disappears. However remnants of PALS remain and the amount of collagen I and collagen III (argyrophilia) increases
L. Jeffrey Medeiros - One of the best experts on this subject based on the ideXlab platform.
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Pathology of Non-Hodgkin’s and Hodgkin’s Lymphomas
Neoplastic Diseases of the Blood, 2012Co-Authors: L. Jeffrey MedeirosAbstract:Non-Hodgkin lymphomas (NHLs) are neoplasms that arise from lymphocytes of either B- or T-cell lineage or rarely from histiocytes. The anatomic location and many of the biologic features of various NHL types can be related to their normal counterparts. Normal B-cells are concentrated in the follicles and medullary Cords of lymph nodes and in the follicles of the spleen [1]. The lymphoid follicles represent the proliferative site of the B-cell system. Upon antigen stimulation, secondary germinal centers develop in which rapid cell division of B-cells takes place. The medullary cord region of the lymph node represents the secretory component of the B-cell system. By contrast, T-cells are selectively concentrated in the paracortical regions of lymph nodes and within the periarterial lymphoid sheaths of the spleen. In addition, small numbers of T-cells are found within follicles where they help in the induction of B-cell differentiation [2, 3]. Histiocytes are preferentially found in the subcapsular and medullary sinuses of lymph nodes and the Cords of Billroth in the splenic red pulp. Histiocytes are also a part of the reticuloendothelial system of the liver and lung. Tissue histiocytes have two broad categories of function. Most histiocytes are phagocytic, whereas a minority of specialized cells is involved in antigen processing and presentation to B- and T-cells [4].
Zhiyong Liang - One of the best experts on this subject based on the ideXlab platform.
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Hepatosplenic γδ T-cell lymphoma
World Journal of Gastroenterology, 2005Co-Authors: Shuanzeng Wei, Tong-hua Liu, De-tian Wang, Jin-ling Cao, Yufeng Luo, Zhiyong LiangAbstract:AIM: To investigate the clinicopathologic characteristics, immunophenotype and TCR gene rearrangements of hepatosplenic T-cell lymphoma in eight Chinese patients. METHODS: Eight Chinese patients with hepatosplenic γδ T-cell lymphomas were studied. Hematoxylin-eosin-stained slides and clinical histories were reviewed. We also carried out immunohistochemical staining for CD3, CD4, CD8, CD20, CD43, CD56, CD79a, UCHL-1, and TCR γδ. Rearrangements of TCR gamma and delta chain genes were also studied. RESULTS: The spleens were enlarged and the cut surfaces were homogeneous and red-purple in color without identifiable gross lesions or enlarged hilar lymph nodes. Histologically, lymphoma cells infiltrated the Cords of Billroth and often packed the sinuses. Liver biopsy showed lymphoma cell infiltrations in the sinusoids, and three cases showed involvements of the portal tracts. Immunohistochemically lymphoma cells were positive for CD3, CD43, and CD56 in all cases. Four of eight cases were positive for CD8, and all cases were negative for CD4 (6/6). Monoclonal rearrangements of TCR γ gene were demonstrated by PCR analysis in five out of the eight cases. TCR δ gene rearrangements were detected in six out of the eight cases, which demonstrated single bands on PAGE gel, and the amplification products in two cases were confirmed by sequencing. CONCLUSION: The clinicopathology of hepatosplenic γδ T-cell lymphoma in Chinese patients is similar to what was previously reported except that the splenomegaly is not so massive, and CD8 is positive.
Shuanzeng Wei - One of the best experts on this subject based on the ideXlab platform.
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Hepatosplenic γδ T-cell lymphoma
World Journal of Gastroenterology, 2005Co-Authors: Shuanzeng Wei, Tong-hua Liu, De-tian Wang, Jin-ling Cao, Yufeng Luo, Zhiyong LiangAbstract:AIM: To investigate the clinicopathologic characteristics, immunophenotype and TCR gene rearrangements of hepatosplenic T-cell lymphoma in eight Chinese patients. METHODS: Eight Chinese patients with hepatosplenic γδ T-cell lymphomas were studied. Hematoxylin-eosin-stained slides and clinical histories were reviewed. We also carried out immunohistochemical staining for CD3, CD4, CD8, CD20, CD43, CD56, CD79a, UCHL-1, and TCR γδ. Rearrangements of TCR gamma and delta chain genes were also studied. RESULTS: The spleens were enlarged and the cut surfaces were homogeneous and red-purple in color without identifiable gross lesions or enlarged hilar lymph nodes. Histologically, lymphoma cells infiltrated the Cords of Billroth and often packed the sinuses. Liver biopsy showed lymphoma cell infiltrations in the sinusoids, and three cases showed involvements of the portal tracts. Immunohistochemically lymphoma cells were positive for CD3, CD43, and CD56 in all cases. Four of eight cases were positive for CD8, and all cases were negative for CD4 (6/6). Monoclonal rearrangements of TCR γ gene were demonstrated by PCR analysis in five out of the eight cases. TCR δ gene rearrangements were detected in six out of the eight cases, which demonstrated single bands on PAGE gel, and the amplification products in two cases were confirmed by sequencing. CONCLUSION: The clinicopathology of hepatosplenic γδ T-cell lymphoma in Chinese patients is similar to what was previously reported except that the splenomegaly is not so massive, and CD8 is positive.
Paul M. Parizel - One of the best experts on this subject based on the ideXlab platform.
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Vascular pathology of the spleen, part I.
Abdominal Imaging, 2004Co-Authors: A. M. De Schepper, Filip Vanhoenacker, B. Op De Beeck, Jan Gielen, Paul M. ParizelAbstract:Quite often, the spleen is regarded as the ‘‘silent and forgotten’’ organ of the abdomen. Although primary splenic diseases are rare, the spleen is a frequent site of secondary manifestations in a wide range of hematologic, immunologic, oncologic, infectious, vascular, and systemic disorders. Despite this broad spectrum of splenic diseases, the radiologic literature on splenic pathology is rather sparse. The introduction of cross-sectional imaging modalities opened up new diagnostic horizons. Ultrasound (US) rapidly became a suitable method for screening abdominal pathology. Despite a low specificity, US provides a high sensitivity for the identification of focal splenic lesions. During the 1980s, due to its superior contrast resolution, computed tomography (CT) became the gold standard for splenic imaging. Currently, helical, volumetric CT scanning with bolus injection of contrast material is considered the state-of-the-art imaging modality for evaluation of the spleen. Magnetic resonance imaging (MRI) has shown great promise due to its superior tissue-characterization ability in selected cases. The spleen is surrounded by a capsule that sends out trabeculae that divide the parenchyma or splenic pulp into incomplete compartments. The white pulp contains arterioles surrounded by a sheath of densely packed, small lymphocytes that are subdivided into central, intermediate, and peripheral marginal zone that form a lattice for the red pulp, which consists of large, thinwalled sinusoids lined by fenestrated endothelium that are filled with blood and separated by thin plates of Cords of lymphoid tissue, the Cords of Billroth. The structure of the spleen is built around its blood supply. There are two models of circulation within the spleen, open and closed. In the closed circulation model, central arteries supply the white pulp, blood runs through a system of marginal zone sinuses that drain directly into the venous sinuses. In the open circulation model, central arteries supply the red pulp and form sheathed capillaries that drain into the splenic parenchyma, which consists of a stellate network of the splenic Cords. Venous sinuses flow together to become trabecular veins that unite at the hilus to form the splenic vein. The closed circulatory system consists of a small (10%) fast flow compartment, Whereas the open system consists of a large (90%) slow flow compartment. The mixture of the two circulation models is most likely the reason for the nonhomogeneous, flamelike enhancement of the spleen on the early arterial phase of CT or MRI (Fig. 1), whereas the spleen will enhance homogeneously on the late arterial and venous phases. This pictorial essay refers to lesions involving the splenic vessels and to the consequent splenic parenchymal pathology of such lesions. The spleen also plays a major role in portal hypertension, and splenic vessels are involved in the development of collateral pathways.