Inbam Indrasingh

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.

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.

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°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. Clin. Anat. 13:177–180, 2000.

Different subsets of Langerhans cells in human uterine tubes and uterus

Langerhans cells (LC) are antigen‐presenting cells present in tissues with high antigenic exposure. Their role in the upper female reproductive tract is not fully understood. This study aims to determine the distribution and morphology of LC in the normal and post‐partum human uterine tubes and uterus by staining with the specific LC markers, CD1a and zinc iodide‐osmium (ZIO), and to determine their association with helper and cytotoxic T cells.

Langerhans cells in the human tympanic membrane in health and disease: a morphometric analysis.

Hypothesis The normal tympanic membrane contains Langerhans dendritic cells, and they play a role in the pathogenesis of chronic suppurative otitis media. Background The presence of Langerhans dendritic cells in the normal tympanic membrane is disputed. However, they have been identified in tympanic membranes of patients with otitis media. A quantitative analysis of the distribution and morphology of these cells in the types of chronic suppurative otitis media has not been undertaken. Methods Samples of normal cadaveric tympanic membranes and those from patients with chronic suppurative otitis media of the tubotympanic and atticoantral varieties were stained with the immunohistochemical marker CD1a. The number of cells per unit length of basement membrane, diameters of cells, and number and length of dendritic processes were compared between the groups. Results CD1a-positive Langerhans dendritic cells were present in the normal tympanic membrane. The number of cells per unit length of basement membrane, diameters of cells, and the length of dendritic processes increased significantly in tubotympanic disease and in atticoantral disease, the difference being more pronounced in the latter form of otitis media. Conclusion Langerhans cells are present in the normal tympanic membrane, and they probably play differing roles in the pathogenesis of tubotympanic and atticoantral forms of chronic suppurative otitis media.

Morphological Study of Dendritic Cells in Human Cervix by Zinc Iodide Osmium Method

BACKGROUND Dendritic cells (DCs) are a heterogeneous population of antigen presenting cells that have been identified in several tissues including the female reproductive organs. The aim of the present study is to demonstrate the morphological differences of dendritic cells in normal human exocervix using the Zinc Iodide Osmium (ZIO) procedure. MATERIALS AND METHODS Normal cervical tissues obtained from nine patients who underwent abdominal hysterectomies for various ailments were processed for histochemical study. Six microns thick serial sections were taken and viewed under a light microscope. The diameters of the cells were measured under a magnification of 40x using the Cellsens image analysing software and analysed using SPSS version 16. RESULTS AND CONCLUSION In the normal human exocervix, a greater density of ZIO-positive DCs was noted in the epithelium and subepithelium and their distribution was not uniform. In some areas of epithelium, the ZIO-positive cells in the basal layer showed a typical dendritic morphology, while the cells in the intermediate and superficial layers were nondendritic polygonal cells. Intraepithelial capillaries were noted, which were surrounded by ZIO-positive nondendritic polygonal cells. There was significant difference in the mean diameters of typical DCs (8.61±1.86 μm) and nondendritic polygonal cells (10.97±1.93 μm). In the subepithelium the DCs had typical morphology and their distribution varied. ZIO positive DCs were noted in the epithelium and cervical glands of endocervix also. In conclusion, the human cervix has different subsets of ZIO positive DCs with varied distribution. Their functional role has yet to be defined.

A case of communicating rami between the median and musculocutaneous nerves passing through the substance of an accessory head of biceps brachii.

Sir, During routine dissection of a 60-year-old male cadaver in the Anatomy department, multiple neuro-muscular anomalies in the left arm were noted. The biceps brachii had an accessory head originating from the anteromedial surface of the middle of shaft of humerus. These muscle fibers inserted into the bicipital tendon from the medial aspect. The median nerve gave a variant high branch in the middle of the arm. The musculocutaneous nerve pierced the coracobrachialis, gave branches to the long and short heads and terminated in the accessory head of the biceps. Two communicating rami were seen between the terminal part of the musculocutaneous nerve and the high branch of the median nerve, located 18 and 19 cm from the corocoid process, respectively. These communications pierced the fibers of the accessory head [Figure 1]. The branch of the median nerve in the arm received the communicating branches from the musculocutaneous nerve, supplied the brachialis and continued as the lateral cutaneous nerve of the forearm [Figure 2]. Figure 1 Dissection of the left arm. Note the median nerve (MN) giving an accessory branch (Ma) in the arm. The musculocutaneous nerve (McN) is seen piercing coracobrachialis (Cb) and giving a branch to supply the short (Bs) and long heads (Bl) of biceps brachii. ... Figure 2 View of dissected left axilla, arm and upper forearm. Notice how accessory branch (Ma) of the median nerve (MN) continues as the lateral cutaneous nerve of forearm (LCF) after supplying the brachialis (B). Sc-coracoid process of scapula; UN-ulnar nerve; ... Variations in the innervation of the flexors of the arm include absence of the musculocutaneous nerve wherein the flexors are supplied by the median nerve;[1] the musculocutaneous nerve supplying coracobrachialis and then joining the median nerve;[2] or communications between the two nerves without change in innervation of the flexors.[3] Differences in innervation are often associated with the presence of accessory head of biceps brachii.[4] One report described a proximal nerve supplying the coracobrachialis and the long and short heads of biceps brachii, while a distal branch from the median nerve supplied the third head of biceps brachii and brachialis, and continued as the lateral cutaneous nerve of the forearm.[5] This differs from the present case in the innervation of the third head of biceps brachii as well as the absence of communications between the two nerves. Knowledge of these variations is important while evaluating neurological deficits. High injuries to the median nerve could result in an unusual pattern of motor and sensory deficit including weaker flexion at the elbow and hyposthesia of the lateral aspect of the forearm. Similarly, injury to the musculocutaneous nerve may not present with the typically expected deficits. It is also important for surgeons to keep in mind the possibility of an aberrant high branch of median nerve while operating in the arm. The communicating branches, in this case, were found within the substance of the accessory head of biceps. This could potentially result in entrapment neuropathy. In conclusion, for the first time, in a case of communication between the median and musculocutaneous nerves, we report the communications lying within the substance of the accessory head of biceps brachii. The median nerve gave a high branch in the arm and the distribution of the median nerve was variant, taking over part of the normal distribution of the musculocutaneous nerve. Knowledge of variations in innervation is important in clinical evaluation of peripheral nerve injuries as well as exploratory surgeries in the arm.

Demonstration of CD1a‐positive and zinc iodide‐osmium‐positive Langerhans cells in the human eyelid

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

Abstract 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.