Structural and immunophenotypic characterization of high endothelial venules in rat and human tissue

To present additional data on high endothelial venule [HEV] structure and immunophenotype. We used the zinc iodide-osmium tetroxide technique [ZIO], which is a metallophilic fixation and staining technique to examine HEVs at light and electron microscopic levels as this technique was previously reported to be reactive with cells in HEVs. Tonsils and lymph nodes were obtained from the Surgery and Otorhinolaryngology Departments, Hacettepe University Hospital, Ankara, Turkey during 2002 and 2003. An indirect immunohistochemical technique was used to examine frozen human tissue samples. Organelle rich high endothelial cells, sheet-like processes of pericytes surrounding HEVs, structural relation of pericyte processes with fibroblastic reticular cells, an unusual multivesicular body-like organelle within high endothelial cells were presented. Expression of a large panel of defined and yet non-defined antigens on HEVs are also presented using an indirect immunoperoxidase technique. Presence of some of these antigens on HEVs was previously reported while no previous report is available for others. Significance of the expression of these antigens in HEVs, structural hints for trans endothelial migration of lymphocytes and their travel along the reticular cell meshwork is briefly discussed

Fibroblastic reticular cells and fibroblast-like cells determined by monoclonal antibodies B-F45 and B-D46 in humans

Identification of stromal microenvironmental components of lymphoid organs is relatively harder at light microscopic level as few markers, which are mostly not very specific, are available to be used for such a purpose. We screened a large panel to determine monoclonal antibodies [mAbs] those reactive with fibroblasts/fibroblast-like cells aiming to obtain further evidence for the organization and function of this cell group. Tissue samples of forty patients undergoing surgery in Otorhinolaryngology, Obstetrics and Gynecology, Orthopedics and Traumatology, Cardiovascular Surgery and General Surgery Departments, Hacettepe University Medical Faculty Hospital, Ankara, Turkey, due to different pathologies obtained as partial specimens of surgery which were apart from pathological examination were immunostained by indirect immunoperoxidase method in Histology and Embryology department in 2003. Among the screened monoclonal antibodies, monoclonal antibodies B-F45 and B-D46 reacted with the members of the family, therefore examined in detail in available human organs. Among the unique staining patterns of these mAbs, reactivity on fibroblastic reticular cells, perineural sheet cells pericryptal/perivillous fibroblasts were striking. Both mAbs will provide useful tools for further studies on stromal network of peripheral lymphoid organs and peripheral nerves

Light and electron microscopic examination of human subungual tissue Glomus and lamellated bodies

There is only limited data related to the subungual glomus body. We therefore studied the structure of this organ, aiming to obtain further evidence. Additionally, we encountered undefined receptor like structures in close association with these glomus cells, named them as lamellated bodies and examined both of the structures at light and electron microscopic levels. This study was carried out at the Faculty of Medicine, Hacettepe University, Ankara, Turkey, during the time period May 2001 to March 2002. In this study, the subungual tissues of 4 patients were examined. Within subungual tissue, 2 groups of morphologically significant structures were determined by light microscopy. The first structure was described as glomus body. It was characterized as an encapsulated structure, rich in rounded clear cells filling its central compartment. The latter structure having a lamellated appearance was described as lamellated body. In the electron microscopic examination, lamellated bodies were characterized by central filament rich large cells and surrounding cytoplasmic processes of ensheathing cells, some of which were vacuolated. Glomus bodies were surrounded by a capsule and centrally located numerous rounded cells which reflected the structural features of an active cell. The lamellated bodies are very unusual structures and they are not found in any other part of the body. The structural organization of the ensheathing cells in the lamellated bodies greatly resembles many skin associate receptors. Therefore, we planned future studies by using immunohistochemistry, to reveal nervous elements for structural contribution