Respiratory bronchiolitis following long-term ozone exposure in bonnet monkeys: a morphometric study.

To quantitate the response of respiratory bronchiolar (RB) epithelium and peribronchiolar connective tissue (PCT) to chronic exposure to high ambient levels of ozone, two groups of 8 adult male bonnet monkeys each were subjected 8 h daily for one year to 0.64 ppm (UV standard) ozone or filtered air, respectively. Blocks of tissue selected throughout the lung and from first generation RBs following airway microdissection had the following significant exposure-related changes: 57% greater volume of RB in the lung, 27% smaller diameter of RB lumen, 179% thicker media and intima of peribronchiolar arterioles, 61% thicker RB epithelium, and 77% thicker PCT.

Carbohydrate cytochemistry of rhesus monkey tracheal epithelium.

Three types of nonciliated secretory epithelial cells contribute material to the mucous lining of pulmonary airways: mucous cells, serous cells, and Clara cells. Extensive interspecies variation exists, especially between humans and laboratory mammals, with regard to occurrence, distribution, and granule content of these secretory cells. This study was designed to characterize one aspect of these differences in one species of nonhuman primate, the rhesus monkey.

The tracheobronchial epithelium of the bonnet monkey (Macaca radiata): a quantitative ultrastructural study.

Since there are major differences between the airway epithelium of man and that of common laboratory species, the tracheobronchial epithelium of the bonnet macaque was characterized to evaluate its usefulness as a model for study of human conducting airways. This study compared the light microscopic, scanning electron microscopic, and ultrastructural appearance of epithelium from the posterior membranous and anterior cartilaginous trachea and mainstem bronchus. Population densities, epithelial volumetric densities, and frequency distributions of cross-sectional areas of nuclei were determined for cell types present on electron micrographs.

The response of the macaque tracheobronchial epithelium to acute ozone injury. A quantitative ultrastructural and autoradiographic study.

The tracheal epithelium of a variety of laboratory species is widely used as a model system in studies of epithelial biology and respiratory carcinogenesis. The purpose of this study was to evaluate the response of the tracheal epithelium to cytotoxic injury in a primate species that may have an epithelium more representative of that in man than smaller laboratory species. This study evaluated changes in the light-microscopic, surface, and ultrastructural appearance of the tracheobronchial epithelium of bonnet monkeys exposed for 3 or 7 days to 0.

Lung development in the nephrectomized ovine fetus.

The effect of fetal nephrectomy on lung development was studied in sheep. Fetal kidneys were removed early in the canalicular stage of lung development (95 to 99 days of pregnancy) and lung structure examined during the alveolar stage (125 to 134 days of gestation). Progesterone and estradiol 17 beta concentrations in maternal and fetal plasma were normal for gestational age, thus indicating that the ewes were not close to labour at the time the fetuses were removed.

Tracheobronchial epithelium of the sheep: II. Ultrastructural and morphometric analysis of the epithelial secretory cell types.

In a light microscopic study we have described the morphology and distribution of six distinct, granule-containing cells in the tracheobronchial epithelium of sheep lung. We designed the present study to determine qualitatively and quantitatively whether these six cell types differ in ultrastructural morphology. Cell height varied from 30.

An immunocytochemical/histochemical approach to tracheobronchial mucus characterization in the rabbit.

Monoclonal antibodies have been made against components of rabbit respiratory mucous secretions, and these were used to localize secretory products in the respiratory epithelium by immunocytochemical methods. The antigen recognized by one antibody was localized within granules of mucous cells containing sulfated glycoprotein. This antibody also reacted with the ciliated surface layer of upper respiratory airways and mucous cells of colonic epithelium.

Carbohydrate cytochemistry of tracheobronchial airway epithelium of the rabbit.

Three types of nonciliated secretory epithelial cells contribute to the mucous lining of pulmonary airways: mucous cells, serous cells, and Clara cells. Contrary to observations in other species, airways of the rabbit have very few mucous cells. In the rabbit, the predominant secretory cell throughout the entire airway tree, including the trachea, appears to be one cell type, the Clara cell.

Triamcinolone-induced structural alterations in the development of the lung of the fetal rhesus macaque.

To test the effect of dose and time on fetal lung maturation by exogenous glucocorticosteroids, triamcinolone acetonide was given to time-mated pregnant rhesus macaques (Macaca mulatta). Triamcinolone acetonide (10 mg/kg or 1 mg/kg) was administered intramuscularly during the midpseudoglandular (63 to 65 days' gestational age) or midcanalicular phase (110 to 112 days' gestational age) of lung development. Fetectomies were performed at 90, 120, or 150 days' gestational age.

Comparison of nonciliated tracheal epithelial cells in six mammalian species: ultrastructure and population densities.

Three types of nonciliated epithelial cells in mammalian conducting respiratory airways are thought to be secretory: mucous (goblet) cells, serous epithelial cells, and Clara cells. Mucous and serous cells are considered to be the secretory cells of the trachea. Clara cells are considered to be the secretory cells of the most distal conducting airways or bronchioles.

Centriacinar alterations in lungs of cats chronically exposed to diesel exhaust.

This study describes the morphologic changes in the centriacinar regions of lungs following long-term exposure of cats to diesel exhaust. Nine male cats (13 months of age) from a minimal disease colony were exposed to diesel exhaust for 8 hours/day, 7 days/week for 27 months. Eight cats were exposed to filtered air.

Distribution of nonciliated bronchiolar epithelial (Clara) cells in intra- and extrapulmonary airways of the rabbit.

Three types of nonciliated secretory epithelial cells are thought to contribute to the mucous lining of intrapulmonary airways: mucous cells, serous cells, and Clara cells. The Clara cell is distinguished from the other two by low cuboidal shape, presence of membrane-bound electron-dense ovoid secretory granuLes, abundant apical agranular endoplasmic reticulum (AER), and its location as the lining cell of distal conducting airways (bronchioles). The present study was designed to define the distribution of the Clara cell within the trachea and intrapulmonary airway tree.

Structure as revealed by airway dissection. A comparison of mammalian lungs.

Microdissection of mammalian pulmonary airways demonstrates branching patterns and provides precisely defined tissue samples for morphologic study. The dissections are performed on lung fixed by airway infusion at standard pressures. Using fine scissors and a high resolution dual-viewing dissecting microscope, extrapulmonary and intrapulmonary airways are dissected down their axial pathways.

Estimation of cell numbers and volumes of bronchiolar epithelium during rabbit lung maturation.

To estimate the numbers and volumes of bronchiolar epithelial cells during lung maturation, we examined rabbits at three time points, 30 days gestation and 4 and 17 weeks postnatal age. Morphometric measures (mean caliper diameter, surface area, and volume) of nonciliated and ciliated bronchiolar cell nuclei, using computer modeling from serial sections, showed a significant decrease in nuclear size for both cell types and a significant increase in cell volume for the nonciliated bronchiolar cell during lung maturation. A shape coefficient (beta) proved to be the most efficient estimator of the number of cells per unit volume when it was used with estimates of the number of nuclei per unit area and the volumetric density of nuclei.

Cytodifferentiation of the nonciliated bronchiolar epithelial (Clara) cell during rabbit lung maturation: an ultrastructural and morphometric study.

The nonciliated bronchiolar epithelial (Clara) cell of adult lung is commonly defined by two cellular components: abundant agranular endoplasmic reticulum (AER) and electron-dense ovoid secretory granules. These reflect the Clara cell's proposed functions as the source of bronchiolar surface secretions and the site of xenobiotic metabolism via the cytochrome P-450 monooxygenase system. Since previous studies have indicated that Clara cells may not attain a fully functional state until some weeks after birth, the present study was undertaken to characterize systematically the differentiation of this cell type during lung maturation.

Morphometry of in situ and lavaged pulmonary alveolar macrophages from control and ozone-exposed rats.

Effects of ambient levels of ozone on cell size and compartments were determined morphometrically for both in situ and lavaged pulmonary alveolar macrophages from rats exposed to filtered air or to filtered air with 0.60 ppm ozone. The ozone exposure was 8 hr/day for 3 days.

Tracheobronchial epithelium of the sheep: I. Quantitative light-microscopic study of epithelial cell abundance, and distribution.

Glutaraldehyde-infused tracheas and airways of five castrated sheep were microdissected following the axial airway of the left cranial and caudal lobes. Airway branches were assigned binary numbers indicating their specific location in the tracheobronchial tree. Samples of known airway generation were resin embedded and examined by light-microscopy.

Ultrastructure of the nonciliated bronchiolar epithelial (Clara) cell of mammalian lung. III. A study of man with comparison of 15 mammalian species.

Two morphologic characteristics have been used to define the nonciliated bronchiolar epithelial cell: (1) abundance of agranular endoplasmic reticulum (AER) and (2) numerous membrane-bound ovoid granules. In this study, we examined lobectomy specimens from three nonsmoking humans: one male (9.5 yr) and two females (62 and 43 yr) for comparison with lung specimens from mammalian species used as experimental models in lung research.

Ultrastructure of the nonciliated bronchiolar epithelial (Clara) cell of mammalian lung: I. A comparison of rabbit, guinea pig, rat, hamster, and mouse.

The morphologic characteristics have been used to define the nonciliated bronchiolar epithelial: (1) abundance of agranular endoplasmic reticulum (AER) and (2) numerous membrane-bound ovoid granules. To quantitatively and qualitatively assess the ultrastructural homogeneity of this lung cell type among laboratory mammals used in lung research, we examined tissue from adult male rabbits, guinea pigs, rats, hamsters and mice. Following fixation by airway infusion at constant pressure (30 cm H2O), lungs were processed by a selective embedding technique and bronchioles of known anatomic location were examined by electron microscopy.

Ultrastructure of the nonciliated bronchiolar epithelial (Clara) cell of mammalian lung: II. A comparison of horse, steer, sheep, dog, and cat.

Two morphologic characteristics have been used to define the nonciliated bronchiolar epithelial cell: abundant agranular endoplasmic reticulum (AER) and membrane-bound avoid granules. To assess the ultrastructural homogeneity of this cell type in the lungs of large domestic mammals used as experimental models in pulmonary research, we evaluated lungs of horse, steer, sheep, dog, and cat. Bronchioles of known anatomic location were examined by electron microscopy following fixation by airway infusion at standard pressure and processing by selective embedding techniques.

Cytochrome p-450: localization in rabbit lung.

Cytochrome P-450-dependent monooxygenase systems, which metabolize endogenous as well as foriegn compounds, are found in hepatic and several extrahepatic tissues of mammals, including humans. A form of cytochrome P-450 is localized in the nonciliated bronchiolar epithelial cells (Clara cells) of the small airways of rabbit lung. The apparent high concentration of the cytochrome in this pulmonary cell type compared to liver may be an important determinant in the susceptibility of the lung to a number of toxic chemicals that undergo metabolic activation.

Pulmonary alterations in rats exposed to 0.2 and 0.1 ppm ozone: a correlated morphological and biochemical study.

Weanling male Sprague-Dawley rats were fed either a synthetic diet supplemented with 11 mg vitamin E/kg body weight (to approximate average U.S. human dietary intake) or a commercial rat chow for 5 wk.

Alterations in the ultrastructure of nonciliated bronchiolar epithelial (Clara) cells by streptozotocin-induced diabetes in rats.

Recent studies showed marked alterations in type II pneumocyte ultrastructure by streptozotocin-induced diabetes. To see whether other pulmonary epithelium is affected, we examined terminal bronchioles by transmission electron microscopy. Ten adult male rats received one intrajugular injection of streptozotocin (75 mg/kg of body weight) and were killed 14 days later.