Methods for the Morphological Study of Tracheal and Bronchial Glands
Joan Gil in 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.
Physiology of the Airways
Anthony J. Hickey, Sandro R.P. da Rocha in Pharmaceutical Inhalation Aerosol Technology, 2019
Located in the submucosa of cartilage-containing airways and in the lamina propria of the trachea are glands that secrete mucus into the airway lumen (Reid, 1960). Each mucous gland consists of four regions: the ciliated duct, collecting duct, mucous tubules, and secretory tubules (Meyrick et al., 1960). The ciliated duct opens to the lumen of the airways and is lined by ciliated epithelial cells. It merges with the collecting duct, the walls of which comprise columnar cells. Mucous cells line the mucous tubules that lead from the collecting duct. Serous cells (which contribute to the more liquid component of mucus) line the blind-ended serous tubules that are located at the distal ends of the mucous tubules. Several secretory tubules feed into the collecting duct. Mucus is secreted via the collecting and ciliated ducts into the lumen of the airways. Goblet cells, located in the epithelium of the larger central airways, secrete mucus directly into the airway lumen (Rogers, 1994). Mucus hypersecretion results from an increase in the number and/or size of mucous glands and goblet cells in disease states, such as chronic bronchitis (Finkbeiner, 1999; Rogers, 1994).
The Thymic Defect
Miroslav Holub in 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.
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)).
Airborne particulate matter from goat farm increases acute allergic airway responses in mice
Published in Inhalation Toxicology, 2020
Dingyu Liu, James G. Wagner, Rob Mariman, Jack R. Harkema, Miriam E. Gerlofs-Nijland, Elena Pinelli, Gert Folkerts, Flemming R. Cassee, Rob J. Vandebriel
The BioPM-induced inflammatory response in the airway wall and peri-bronchiolar interstitial tissue (bronchiolitis) consisted of a mixed inflammatory cell influx of polymorphonuclear leukocytes (neutrophils) and lesser numbers of mononuclear leukocytes (mainly lymphocytes) and eosinophils (type 1 immunity/inflammation characteristic of a nonallergic toxic response). Large and small diameter bronchioles were affected as well as centriacinar regions including the terminal bronchioles and proximal alveolar ducts and associated alveoli. Associated with the airway inflammation in the large-diameter, but not small-diameter, bronchioles, was an occasional mucous cell metaplasia (secretory cells with AB/PAS-stained mucosubstances not normally found in bronchioles of mice) in the luminal airway epithelium. However, this epithelial change was of minimal severity.
Inhalation exposure to multi-walled carbon nanotubes alters the pulmonary allergic response of mice to house dust mite allergen
Published in Inhalation Toxicology, 2019
Mark D. Ihrie, Alexia J. Taylor-Just, Nigel J. Walker, Matthew D. Stout, Amit Gupta, Jamie S. Richey, Barry K. Hayden, Gregory L. Baker, Barney R. Sparrow, Katherine S. Duke, James C. Bonner
Mucous cell metaplasia was assessed by imaging all airways under 500 × 500 µm (HxW) in each AB/PAS-stained tissue. The AB/PAS-positive area was measured using NIH ImageJ software (National Institutes of Health, Bethesda, MD, USA) expressing the integrated density of the area of AB/PAS + mucosubstances per unit length of airway basement membrane (Harkema et al. 1987; Zhu et al. 2015). Airway fibrosis was assessed by imaging trichrome stained lung sections and obtaining area to perimeter ratios as described previously (Duke et al. 2017). Briefly, all round to oval shaped airways under approximately 500 × 500 µm (HxW) were imaged at 100x. The lasso tool in Adobe Photoshop CS5 was used to surround trichrome positive collagen around the airways, giving the outer area, and to surround the basement membrane, giving the inner area and circumference (perimeter). The difference between the outer and inner area was divided by the circumference, giving the area/perimeter ratio. All measurements were performed in a blinded manner. For statistical analysis airways were grouped into small (under 300 × 300 µm) and large (above 300 × 300 µm) airways.
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