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Phosphatidylcholine synthesis in isolated type II pneumocytes from ozone-exposed rats (1988)

Bree, Leendert ; Haagsman, Henk P. ; Golde, Lambert M. G. ; [et al.]

Springer

Archives of toxicology 61 (1988), S. 224-228

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ISSN: 1432-0738

Keywords: Ozone ; Phosphatidylcholine synthesis ; Alveolar type II cells ; Pulmonary surfactant ; Rat lung

Source: Springer Online Journal Archives 1860-2000

Topics: Medicine

Notes: Abstract Phosphatidylcholine (PC) synthesis by alveolar type II cells, as an indicator for the production of pulmonary surfactant, was studied after a 4-h exposure of rats to 4 mg ozone/m3 (2 ppm). Lung ravage fluid analysis after exposure revealed significant increases in proteins, which is indicative for pulmonary injury. When type II cells were isolated immediately and thereafter cultured for 20 h, the rate of PC synthesis in cells derived from ozone-exposed rats was not significantly different from that in cells from unexposed controls. Yet, a decreased rate of PC synthesis was observed when these cells were subsequently exposed to ozone in vitro. The activity of the enzyme glycerolphosphate acyltransferase (GPAT) was slightly enhanced in cultured type II cells isolated from ozone-exposed rats, while the lysophosphatidylcholine acyltransferase (LPCAT) activity was unchanged. However, ozone exposure of rats did result in a significant decrease of PC synthesis when measured in freshly prepared type II cell suspensions, although both GPAT and LPCAT activities were not affected. It is concluded that a decrease in pulmonary surfactant related PC synthesis after ozone exposure of rats can be demonstrated in freshly isolated type II pneumocytes. Cultured type II cells from exposed rats lack this effect and are therefore less useful to study changes in phospholipid biosynthesis after in vivo ozone exposure. The data on in vitro ozone exposure of cultured type II cells, however, support the view that ozone may impair pulmonary surfactant production.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1007/BF00316638

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Evidence for ionic clusters in butadiene-methacrylic acid copolymers neutralized with various salts (1974)

Pineri, M. ; Meyer, C. ; Levelut, A. M. ; [et al.]

New York : Wiley-Blackwell

Journal of Polymer Science: Polymer Physics Edition 12 (1974), S. 115-130

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ISSN: 0098-1273

Keywords: Physics ; Polymer and Materials Science

Source: Wiley InterScience Backfile Collection 1832-2000

Topics: Chemistry and Pharmacology , Physics

Notes: Effects of neutralization on butadiene-methacrylic acid copolymers have been studied. In Hycar CTB with 2% acid groups, small-angle x-ray scattering gives evidence of some cation clustering and leads to a value of the mean radius of 5.6 Å for the clusters and a value of the distance between them of 70 Å. When the concentration of salt is increased there is no appreciable change in the distance between clusters or in their size, but their number increases. The structure of clusters has been studied by electron paramagnetic resonance in copolymers neutralized with copper salts. The appearance of a line as in the monohydrated acetate salt permits one to define the structure of clusters consisting of two Cu2+ and four RCOO- ions with two H2O or RCOOH molecules. When the temperature is increased, the signal corresponding to Cu2+-Cu2+ pairs disappears. In high molecular weight butadiene methacrylic acid copolymers with 9% acid groups, we have found the ion pair clusters gathered into larger clusters. In dynamic mechanical properties, a relaxation peak appears at 340°K. We interpret this as due to breaking and possible re-forming of dipolar associations.

Additional Material: 14 Ill.