Clara enzymes

Inhibitors of the microsomal enzymes decreased the covalent binding and the Clara cell necrosis and increased the LD50, even though the blood and pulmonary levels of ipomeanol... 

Certain furan derivatives show selective organ toxicity in animals. One such chemical is 4-ipomeanol (54 see Table 8 for structures), which is toxic to specific cells (Clara cells) in the lungs of treated animals (77MI10501). Administration results in bronchiolar cell necrosis, extensive pulmonary oedema and subsequent death of the animal. Experiments have shown that ipomeanol is localized within the Clara cell (77MI10501), which is considered to be rich in cytochrome P450 (78MI10505), an important enzyme complex for metabolism. The ipomeanol is then converted via the cytochrome P450 into an activated species that alkylates... 

The trachea and bronchi likewise have a protective function. Mucous and serous cells secrete fluids that together comprise the mucus, which is moved toward the pharynx by the cilia of the ciliated cells. The movement of mucus serves to move entrapped particles toward the pharynx where they are eliminated by swallowing or expectoration. The mucus may also have other protective functions, protecting the epithelial cells by free radical scavenging and antioxidant properties. The Clara cells are known to contain high concentrations of xenobiotic metabolizing enzymes. 

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. 

Immunohistochemical analysis of the distribution of P450 reductase in lung tissue demonstrated that in the control mice this enzyme was expressed most strongly in the cihated ceUs of the proximal and distal bronchi and in the Clara ceUs of the small or terminal bronchioles (Lim et al. 1998). Cu/Zn superoxide dismutase and Mn superoxide dismutase were detected primarily in the cihated cells of the bronchial epithehum. 

Most experiments with cytochrome P450 and other microsomal enzymes were performed on the Uver. But Clara cells have even higher levels of cytochrome P450 than do the hepatocytes (Serabjit-SiNGH et al. 1980), and are rather selectively injured by number of simple compounds as Usted in Table 21. 

F. Antonio, R. Guillem, T. Sonia, M. Clara, G. Piergiorgio, C. Valeria, C. Gianluca, and T. Tzanov, Cross-hnked collagen sponges loaded with plant polyphenols with inhibitory activity towards chronic wound enzymes, Biotechnol. J., 6 (10), 1208-1218,2011. 

The effect of various commercially available enzyme preparation in the HPLC determination of riboflavin and thiamine in foods was studied by M. Hagg (57). Different enzymes (takadiastase, clara-diastase, a-amylase), as well as the same enzyme produced by different manufacturers, strongly affected the determination of both vitamins. The recoveries for different foods ranged from 85% to 100% for thiamine and from 80% to 100% for riboflavin. Huka clara-diastase (6%) was the best enzyme in the study. 

---