Clara types

Figure 10.1 Typical tracheo-bronchial and bronchiolar epithelia showing the major cell types. The tracheo-bronchial epithelium showing the pseudostratified nature of the columnar epithelium, principally composed of ciliated cells (C), interspersed with goblet cells (G), brush cells (Br), serous cells (S), Kulchitsky s cells (K) and basal cells (B). The bronchiolar epithelium showing the cuboidal nature of the epithelium, principally composed of ciliated cells (C), Clara cells (Cl) and infrequent basal cells. Muc = mucus Ci = cilia N = nucleus Sec = secretory granules.

In animals, acute oral exposure to doses of 4,000 mg/kg has been observed to cause respiratory edema, atelectasis and hemorrhage (Gould and Smuckler 1971). This is accompanied by marked disruption of subcellular structure in most pulmonary cell types, including granular pneumocytes, capillary endothelial cells and Clara cells (Boyd et al. 1980 Gould and Smuckler 1971 Hollinger 1982). It has been shown that Clara cells were most severely injured because they are the most active in metabolic activation of carbon tetrachloride. Injury to capillary endothelial cells is dose-... 

White, J. F. Foley, R. R. Maronpot, and NT108 M. W. Anderson. Role of Clara cells and type II cells in the development of pulmonary tumors in rats and mice following exposure to a tobacco-specific nitrosamine. Exp Lung Res 1991 ... 

Sato, T. and Kauffman, S.L. (1980). A scaiming electrrai microscopic study of the type II and Clara cell adenoma of the mouse lung, Lab. Invest. 43, 28. 

Clara cells, type II cells and alveolar macrophages) in vitro ... 

DLA, DNA damage, rabbit (macrophage. Clara and type II) lung cells + NT 5 Becher et al. (1993)... 

The pharynx, larynx, trachea and bronchi are lined with pseudostratified, ciliated columnar epithelium that contain at least eight cell types, including mucous secretory goblet and Clara cells, which produce a protective mucus layer of 5-10 jum thickness (see Table 9.2). Subepithelial secretory glands, present in the bronchial submucosa, also contribute to the mucus blanket [9]. Through coordinated ciliary movement a propulsive wave is created, which continuously moves the mucus layer up towards the larynx. Consequently, the mucosal surface of trachea and bronchi is constantly swept to remove inhaled materials. As the bronchi divide into bronchioli, the ciliated columnar respiratory epithelium is much thinner and changes to a simpler non-ciliated cuboidal epithelium. The epithelium in the terminal and respiratory bronchioles consists of ciliated, cuboidal cells and a small number of Clara cells. However, Clara cells become the most predominant type in the most distal part of the respiratory bronchioles [10]. 

Continuous studies were performed in specially prepared microreactors molded from PDMS, designated PDMS (Sylgard 184 silicone elastomer Dow Corning) poured onto silicon wafer molds. The microreactor molds were prepared using 4-in. silicon wafers of Type P, crystal orientation of , resistivity of 1 to 2 Q, and thickness of 457-575 pm from Silicon Quest (Santa Clara, C A). After preparation, mixtures of urease enzyme and PDMS (designated PDMS-E) were poured onto the microreactor mold and allowed to cure at ambient conditions. 

Dutt S (1993) New faster Kernighan-Lin type graph-partitioning algorithms. In Proceedings of the 1993 IEEE/ACM international conference on computer-aided design, Santa Clara, CA, pp 370-377... 

The author would like to thank Chris Howland for editorial assistance and Clara Robison for typing the manuscript. Background researches for this article were supported by FDA Grant FD00568 and NIH Grant AM26031. 

The author thanks Vicky Crampton for checking the references and Clara Robison for typing of the manuscript. 

Many cell types within the lung, such as the bronchial epithelial cells, Clara cells, type II pneumocy tes, and alveolar macrophages, are capable of metabolizing xenobiotics. In rodents and rabbits, however, Clara cells and type II cells are the... 

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