Route of lymphocyte migration through the high endothelial venule (HEV) in human palatine tonsil

Eleven palatine tonsils were collected from subjects who underwent tonsillectomy in Christian Medical College Hospital and the route of migration of lymphocytes through the high endothelial vessel was studied under EM. In the interendothelial route, migration of a lymphocyte through HEV wall began with the adhesion of a lymphocyte to the surface of endothelial cells by means of a short cytoplasmic projection in the vicinity of intercellular space. The projection extended into the cleft between adjacent endothelial cells. The lymphocyte migrated through HEV by diapedesis. After the lymphocyte had traversed the interendothelial space, it occupied the subendothelial space. In the transendothelial route, migration of a lymphocyte through HEV was initiated by adherence of the lymphocyte to the endothelial cell. The adherent lymphocyte compressed or invaginated into the cytoplasm of the endothelial cell, entered the endothelial cell, was completely enclosed within the endothelial cell cytoplasm, and emerged from the endothelial cell to occupy the subendothelial space. Evidence is presented from static transmission electron microscopic pictures for the migration of lymphocytes by both interendothelial and transendothelial routes through the high endothelial venule.     

Electron microscopic demonstration of Langerhans cells in human tonsillar epithelium

Langerhans cells are believed to play an important role in cutaneous immune responses. The tonsils likewise have been regarded as lymphoid tissue performing critical functions in the immune system. The present study was undertaken to determine whether Langerhans cells are present in tonsillar epithelium. Samples of epithelium from four tonsils were processed and examined with an electron microscope. Cells morphologically typical of Langerhans cells were found to be present in the tonsillar epithelium.     

Demonstration of Langerhans Cells (Lcs) in the Intra-Follicular and Inter-Follicular Regions of the Human Palatine Tonsil Ultrastructural and Immunohistochemical Study

Dendritic cells (DCs) and macrophages function to capture and process antigen and present it to T lymphocytes, a critical step in early immune response. The dendritic Langerhans cells (LCs) belong to the system of antigen presenting cells and play a role in cutaneous immune responses. In our previous studies, we have ultrastructurally demonstrated the presence of LCs in the crypt epithelium and surface epithelium of the human palatine tonsil. In the present study our aim was to demonstrate the LCs in the intra-follicular and inter-follicular area of human palatine tonsil by conventional electron microscopy and immunocytochemistry. Here we report the presence of CD1a positive Langerhans Cells (LCs) in the intra-follicular and inter-follicular areas of the human palatine tonsil and confirm their presence ultrastructurally by demonstrating typical Birbeck granules (BGs) in their cytoplasm. Identification of LCs in the intra-follicular and inter-follicular areas of the palatine tonsil supports the migratory nature of the LCs. Apposition between the Langerhans cells and lymphocytes in the intra-follicular area further strengthens the function of Langerhans cells as antigen presenting cells in initiating immune responses in human palatine tonsil.     

Intertubercular sulcus of the humerus as an indicator of handedness and humeral length

Measurements of the maximum width and depth of the intertubercular sulcus (ITS), angles of the medial and lateral walls with the floor of the ITS, as well as the length of the humerus in 100 right and 100 left matched, unpaired dry humeri of 100 adults were statistically analyzed. Since 90–95% of the general population is right handed, on the basis of altered size of the dimensions of the right ITS relative to the left, it is proposed that greater width and smaller angles of the medial and lateral walls of the ITS of one side are indicative of handedness on that side. Handedness can further be deduced by the presence of a <50° angle of the medial wall and of a supratubercular ridge of Meyer on that side. The length of the humerus correlated with the width and depth of the ITS (P < 0.001). Regression equations of the length of the humerus on width, depth, as well as width and depth of the ITS have been derived. © 1995 WiIey-Liss, Inc.     

Quantitative analysis of CD1a (T6) positive Langerhans cells in human tonsil epithelium

Fifty-one human palatine tonsils of both sexes and 4–54 years of age were studied for quantitative analysis of Langerhans cells in the epithelium using CD1a (T6), which is a specific immunological marker for Langerhans cells and indeterminate cells. Cryo-sections were stained using the avidin biotin peroxidase method. Using light microscopy, CD1a-positive dark brown cells with dendritic processes were identified as Langerhans cells, which were located in the epithelium, subepithelial tissue, follicles and interfollicular areas. The Langerhans cells were counted only in the tonsil epithelium per zone of 1.1 mm length of basement membrane. For each biopsy, 25 such zones were studied. The mean number (SEM) of Langerhans cells per zone of tonsil epithelium was found to be 37 (± 0.5). In the male, it was 36 (± 0.7) but in the female, it was 38 (± 0.2). In different age subgroups, the mean number (SEM) varied between 40 (± 1.7) and 14 (± 1.1). In the age subgroups of 11–15, 16–20, and 21–25 years, the mean number showed significant sex differences. Since the 11–15, 16–20, and 21–25 age subgroups in the female showed an increased number of Langerhans cells, it is concluded that the immunological role of the palatine tonsils is increased during puberty and adolescence. In the female, there was a negative correlation (r = −0.196, p < 0.01) between age subgroups and mean numbers, but in the male there was no correlation (r = 0.008). Overall, in all the 51 biopsies together, there was a negative correlation (r = −0.017, p < 0.01) and significant (p < 0.001) sex and age differences.     

Gross morphology and ultrastructure of dendritic cells in the normal human decidua

Five normal placentae of normal pregnancy and delivery were used to study the gross morphology and ultrastructure of the dendritic cells in the normal human decidua. Zinc iodide osmium (ZIO) mixture was prepared. Small pieces of the placenta were processed for light microscopy and electron microscopy. For light microscopy, the small pieces of placenta were incubated in 20 mM PBS-EDTA solution, ph 7.4 at 37 degrees C to detach the basal plate. The basal plate pieces were incubated in ZIO. A wholemount preparation of the basal plate demonstrated the whole profile and gross morphology of the dendritic cell. For electron microscopy, the placenta pieces were fixed in 3% glutaraldehyde in 0.1 M phosphate buffer, ph 7.4, washed with phosphate buffer, put in ZIO mixture, washed in distilled water, dehydrated in graded ethanol, cleared in propylene oxide, and embedded in resin. Ultra thin sections of the ZIO blocks were cut using a diamond knife and stained with lead citrate. Ultrastructure of the dendritic cell presented multiple cytoplasmic processes, lobulated or round or oval, heterochromatic or euchromatic nucleus, mitochondria, free ribosomes, and pieces of rough endoplasmic reticulum, but no Birbeck granules.     

The morphology and distribution of CD1a positive Langerhans cells in normal and squamous cell carcinoma of cervix

Introduction

Langerhans cells (LCs), a type of dendritic cells are the professional antigen presenting cells present in the mucosa surfaces. They play an important role in antitumor immune response. The present study aims to find out the morphology and distribution of CD1a positive LCs in normal and squamous cell carcinoma of cervix.