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Methods for the Morphological Study of Tracheal and Bronchial Glands
Published in Joan Gil, Models of Lung Disease, 2020
In interpreting such morphometric data related to secretory granules and products of submucosal gland, it should be noted that the following possibilities may account for the differences. First, there is more connective tissue or inflammatory or other nonsecretory cells in the more proximal human glands or in the female rat glands, so the proximal or female secretory cells as a whole must have contained relatively less acid mucin and relatively more cytoplasm. Second, the individual secretory granules in the mucous cell will vary in their rates of production and excretion and their initial volumes. For example, Phipps et al. (1986) have studied effects of O3 exposure on sheep tracheal mucus secretion by both measuring radiolabeled glycoprotein release and morphometry of submucosal glands. Although chronic exposure produced glandular hypertrophy, it also induced a decrease in glycoprotein release and the gland cells were devoid of secretory material (granules). With recovery, basal glycoprotein secretion was greatly increased above control and gland cells were full of secretory material.
The Thymic Defect
Published in Miroslav Holub, Immunology of Nude Mice, 2020
The postnatal development of the nude mouse dysgenetic thymus is due to the proliferation of the epithelial cells lining the ducts and forming small acini in the surrounding loose connective tissue.43,44 The acinar cells which have, in part, the appearance of mucous cells are situated at the dead ends of the branching central duct.43 They discharge their product(s) into the lumen. The branching ducts expand and form cyst-like structures. The onset of the process is discernible in about 2-week-old animals. By this time the duct-lining cells differentiate into mucous and ciliated types. At 1 month of age the growth of the paired polycystic organ still proceeds and the maximala dimensions are found after the 3rd month;44 thereafter, the increase of size occurs only in some individuals and is due chiefly to the dilatation of cysts filled by the glycoprotein product. During growth, the acini of mucous cells become associated and incorporated into the walls of the enlarging duct and cyst systems, however, a few mucous cell acini enlarge and persist.
Major Digestive and Endocrine Glands
Published in George W. Casarett, Radiation Histopathology: Volume II, 2019
The submaxillary gland is a mixed (serous-mucous) gland containing many more serous alveoli than mixed alveoli. Mucous cell cytoplasm elaborates the protein muci-gen which when secreted and mixed with water becomes mucin or, with other additions, mucus. Secretory capillaries, such as occur between serous cells, are lacking in mucous alveoli.
A novel sulfur mustard (HD) vapor inhalation exposure model of pulmonary toxicity for the efficacy evaluation of candidate medical countermeasures
Published in Inhalation Toxicology, 2021
Mark R. Perry, Matthew Neal, Roger Hawks, David Pressburger, Jan Satola, Cheryl Triplett, Beth Reed, Meredith Andrews, Jill A. Harvilchuck, Michael S. Nealy, Gennady E. Platoff, David T. Yeung
Animals that died between 2- and 28-days post exposure were exposed to doses ≥0.45 mg/kg HD. The animals that died between 2-days and 7-days post exposure had similar observations to the animals that died within 48-hours, with one animal demonstrating BALT lymphocyte necrosis, and the addition of macrophage inflammation of the airway epithelium. However, the animals that died in this range also demonstrated more evidence of repair and regeneration, with this increasing closer to the 28-day timepoint, as expected. Evidence of repair and regeneration (Figure 10(A–C)) included alveolar epithelium Type II cell hyperplasia, bronchiolo-alveolar hyperplasia, partial regeneration of the bronchial/bronchiolar epithelium by low cuboidal epithelial cells, perivascular neovascularization, bronchial fibroplasia/fibrosis, bronchiole mucous cell metaplasia, and septal/interstitial fibrosis. Additional alterations specific to the larger airways were dilatation of the lumen of the bronchi, bronchial epithelial damage, and intraluminal mucus (likely related to mucous cell metaplasia) both within bronchi/bronchioles and also within clusters of alveoli.
Influence of silica particles on mucociliary structure and MUC5B expression in airways of C57BL/6 mice
Published in Experimental Lung Research, 2020
Qimei Yu, Guoqing Fu, Hui Lin, Qin Zhao, Yuewei Liu, Yun Zhou, Yuqin Shi, Ling Zhang, Zhenyu Wang, Zhibing Zhang, Lingzhi Qin, Ting Zhou
Additionally, silica particles gradually induced mucus hypersecretion on the airway surface and in the submucosal glands of trachea with the prolonged exposure. And our previous study also found enriched mucus secretion in bronchi of lung tissue after silica particles instillation in mice.29 In agreement with our findings, mucin production is markedly elevated in the trachea and bronchi in patients with asthma or COPD.30 There are two possible reasons for these results. First, the damaged structure of cilia caused by silica particles weakens ciliary transport and coordination, resulting in mucus transport failure and adhesion to the airway surface. Second, silica particles induce persistent respiratory inflammatory responses involving various inflammatory cytokines such as IL-1β, which could trigger excessive mucin secretion and mucous cell hyperplasia.21,30,31 It has been reported that moderately high concentration of mucus could compress cilia and slow down mucus transport, whereas severe hyperconcentration can flatten cilia and lead to mucus stasis and adhesion.31 This may support our results that airway epithelial layer became short or flat with increased mucus when exposed to silica particles. Therefore, silica particles might also affect the structure and function of airway cilia by stimulating mucus hypersecretion, which possibly suppress the function of MCC in respiratory tract.
Cytological and histological effects of pesticide chlorpyriphos in the gills of Anabas testudineus
Published in Drug and Chemical Toxicology, 2020
Babu Velmurugan, Elif Ipek Cengiz, Murat Yolcu, Pelin Uğurlu, Mariadoss Selvanayagam
Light and transmission electron micrographs of control fish gills had normal and clear configuration. There were no exceptional structures. The gill was made up of primary lamellae. Secondary lamellae were found on the lateral sides of primary lamellae. The surface of the gill lamellae had a thin epithelial covering. The epithelial cells were flat and had prominent nuclei. Mucous cells, pillar cells, erythrocytes, and chloride cells were other cell types found on primary and secondary lamellae. Mucous cells were present throughout the epithelium. The mucous cells were small round cells filled with secretion (Figure 1(A)). A typical mucous cell was characterized by a basal irregular nucleus, numerous secretion vesicles with different diameters, and electron density which occupy the entire cytoplasm of the cell. Chloride cells were found along the basilamellar region. The chloride cells were described as spheroid with light vesicular cytoplasm, eccentric nuclei, and mitochondria-rich cells. The secondary lamellar epithelium was supported by pillar cells that were contractible and separated the capillary channel. The pillar cells were spool-shaped. They had a centrally located nucleus, cytoplasm contains a few mitochondria, few ribosomes, and little rough endoplasmic reticulum. The capillary channel was filled with erythrocytes (Figure 2(A)).