Morphology of mucosa-associated lymphoid tissue in odontocetes.

This study describes the mucosa-associated lymphoid tissue (MALT) in odontocetes from the Brazilian coast and freshwater systems. Seven species were evaluated and tissue samples were analyzed by light, scanning and transmission electron microscopy, and immunohistochemistry. Laryngeal tonsil was a palpable oval mass located in the larynx, composed of a lymphoepithelial complex. Dense collections of lymphocytes were found in the skin of male fetus and calf. Clusters of lymphoid tissue were found in the uterine cervix of a reproductively active juvenile female and along the pulmonary artery of an adult female. Lymphoid tissues associated with the gastrointestinal tract were characterized by diffusely arranged or organized lymphocytes. The anal tonsil was composed of an aggregate of lymphoid tissue occurring exclusively in the anal canal, being composed of squamous epithelium branches. MALT was present in different tissues and organic systems of cetaceans, providing constant protection against mucosal pathogens present in their environment.

Microarchitecture of the Palatine Tonsil in Sheep (Ovis aries) / Microarquitectura de la Tonsila Palatina en Oveja (Ovis aries)

The tissue pieces of palatine tonsil were collected from different postnatal age groups of sheep from the Corporation Slaughter House, Perambur, Chennai. The palatine tonsil consisted of a surface epithelium, capsule, tonsillar lobes, crypts, crypt epithelium and tonsillar follicles. The surface epithelium over the palatine tonsil was made up of non-keratinized stratified squamous epithelium in all the postnatal age groups studied. The palatine tonsil was clearly demarcated from the surrounding structures by a distinct connective tissue capsule and one septa dividing the tonsil into two lobes. The surface epithelium was invaginated into the substance of the tonsil to form primary and secondary crypts in each lobe. The crypt epithelium covered the regions of lymphoid follicles became lymphoepithelium. The macrophages were also observed in the epithelium. In the areas of lymphoepithelium the basement membrane was interrupted since lymphocytic infiltration was heavy into the epithelium. Numerous secondary tonsillar follicles with germinal centers separated by interfollicular areas were observed in the palatine tonsil. The tonsillar follicles consisted of a mantle zone, which was heavily populated with small darkly stained lymphocytes. These mantle zones were always oriented towards the crypts. The tonsillar follicles of young sheep showed many medium and small sized lymphocytes, lymphoblasts and also reticulocytes. The reticular cells usually appeared larger than lymphocytes and had a more abundant and organized cytoplasm with vacuoles.

Fueron recolectadas piezas de tejido desde la tonsila palatina de ovejas con diferentes edades postnatales, desde la Corporación Slaughter House, Perambur, Chennai. La tonsila palatina consistía en un epitelio de superficie, cápsula, lóbulos de las tonsilas, criptas, epitelio de las criptas tonsilares y folículos. El epitelio superficial sobre la tonsila palatina estaba compuesto, en todos los grupos estudiados, de epitelio escamoso estratificado no-queratinizado. La tonsila palatina se delimitó claramente de las estructuras circundantes por un tejido conectivo capsular y un septo dividiendo la tonsila en dos lóbulos. El epitelio superficial se invaginó dentro de de la tonsila para formar criptas primarias y secundarias en cada lóbulo. El epitelio de las criptas cubrió las regiones de folículos linfoides transfomándose en linfoepitelo. También se observaron macrófagos en el epitelio. En las áreas de linfoepitelo la membrana basal estaba interrumpida por la infiltración linfocitaria y fue mayor en el epitelio. Fueron observados numerosos folículos tonsilares secundarios con centros germinales separados por áreas interfoliculares. Los folículos tonsilares consistían en una zona del manto que estaba densamente poblada con pequeños linfocitos intensamente teñidos. Estas zonas del manto se orientaron siempre hacia las criptas. Los folículos tonsilares de las ovejas jóvenes mostraron muchos linfocitos de tamaño medianos y pequeños, linfoblastos y también reticulocitos. Las células reticulares usualmente aparecían más grandes que los linfocitos y tenían un citoplasma más abundante y organizado con vacuolas.

Morphological changes in the tongue as a consequence of manganese inhalation in a murine experimental model: light and scanning electron microscopic analysis.

Air pollution by suspended particles has become a worldwide health problem. The main sources of these particles are fossils and additives combustion. Mn enters the body through inhalation, but part of the particles accesses contact with tongue's posterior surface where lingual tonsils and lingual papillae are placed. We decided to explore in a mouse model, the impact that the deposit of inhaled Mn has on the tongue's surface. Atrophy of the lingual tonsil, filiform papillae, as well as the swelling of taste buds in fungiform papillae, were the predominant changes. Ferropenic anemia is associated with the changes described and could be related to the interference of Mn in iron metabolism and riboflavin absorption. More research should be done to explore the participation of suspended particles trapped in the oral cavity in toxicology of Mn or other inhaled pollutants.

Histopathology of the palatine tonsil in the newborn infant.

We studied 13 tonsils from newborn infants in order to understand the evolution of the microscopical alterations in tonsils of children with recurrent infections. The weight of the newborns ranged from 0.540 to 3.250 kg. All tonsils had a similar histopathological pattern, independent of the weight of the newborn. The epithelium of the crypt showed no or slight infiltration of lymphocytes. All cases had some dilated crypts with formation of cysts lined by squamous epithelium and filled with squamous debris. The lymphoid tissue was poorly developed and with no differentiation into primary follicles. Similar cysts have been described in recurrent tonsillitis as a result of focal compression of the lumen of crypts by enlarged lymphoid follicles or abscess. However, our narrowing of the lumen of the crypts was near the surface of the tonsils.

Histopathological concept of chronic tonsillitis in children.

The purpose of this study was to ascertain to what degree the clinical entity recurrent tonsillitis (RT) is associated with a histopathological pattern of chronic tonsillitis. Cases of idiopathic tonsillar hypertrophy (ITH) not associated with recurrent infections were used for comparison. We performed a histopathological study of 126 palatine tonsils of children (57 cases due to RT and 69 due to ITH). The following features were evaluated: cryptal reticulation, the relative amount of diffuse and follicular lymphoid tissues, the intensity of parenchymal fibrosis, the papillary arrangements of the epithelium, the amount of debris in the lumen of the crypts, and the presence of keratin cysts. There was no significant quantitative difference between the two groups (RT and ITH) and we did not find a histological distinctive pattern of RT or ITH. Recurrent infection in the tonsils in children is not associated with a histopathological pattern which could be termed chronic non-specific tonsillitis and is clearly distinguishable from idiopathic tonsillar hypertrophy.

Histopathological comparison between tonsil and adenoid responses to allergy.

In a previous study of adenoid tissue from allergic and non-allergic patients, we concluded that in allergic children edema of the "chorium" was present in 80.4% and that treatment with antihistamine drugs may reduce this edema. The purpose of the present study was to compare the histopathology of the palatine tonsil and adenoid from allergic patients. Tissue samples were obtained from 153 patients (56 tonsils and 97 adenoids from allergic children). We analysed the intensity of the edema and its cellular components in the chorium of palatine tonsils and adenoids. The frequently seen edema in the adenoids was significantly different from that in the tonsils. The squamous epithelium of the tonsils was thicker and bad stronger intercellular junctions than the columnar epithelium of the adenoids. This fact probably makes difficult the contact of the antigen with the chorium.