Stimulatory effect of gastroesophageal reflux disease (GERD) on pulmonary fibroblast differentiation.

Epidemiological studies indicate that prolonged micro-aspiration of gastric fluid is associated in gastroesophageal reflux disease with the development of chronic respiratory diseases, possibly caused by inflammation-related immunomodulation. Therefore, we sought to ascertain the effect of gastric fluid exposure on pulmonary residential cells. The expression of α-smooth muscle actin as a fibrotic marker was increased in both normal human pulmonary fibroblast cells and mouse macrophages. Gastric fluid enhanced the proliferation and migration of HFL-1 cells and stimulated the expression of inflammatory cytokines in an antibody assay. Elevated expression of the Rho signaling pathway was noted in fibroblast cells stimulated with gastric fluid or conditioned media. These results indicate that gastric fluid alone, or the mixture of proinflammatory mediators induced by gastric fluid in the pulmonary context, can stimulate pulmonary fibroblast cell inflammation, migration, and differentiation, suggesting that a wound healing process is initiated. Subsequent aberrant repair in pulmonary residential cells may lead to pulmonary fibroblast differentiation and fibrotic progression. The results point to a stimulatory effect of chronic GERD on pulmonary fibroblast differentiation, and this may promote the development of chronic pulmonary diseases in the long term.

Derivatization procedures for the detection of estrogenic chemicals by gas chromatography/mass spectrometry.

This work evaluated derivatization procedures for detecting both natural and synthetic estrogenic chemicals by gas chromatography/mass spectrometry (GC/MS). Different silylating agents, mainly trimethylsilylating (TMS) agents, were compared, and the roles of various content of trimethylchlorosilane (TMCS, as a stimulator) were investigated. The difference in the abundances of the derivatives was caused by the steric hindrance of multiple hydroxyl groups and ethynyl groups in the structures of estrogenic chemicals. The use of TMCS produces an increase in the derivatization yield, especially for the compounds with multiple hydroxyl groups (i.e., 17beta-estradiol (E(2)) and estriol (E(3))). Mass spectra of O-TMS derivatives and tentative fragmentation profiles are proposed. Molecular ions were the base peaks for all the derivatives, and were used as the quantitation ions to obtain maximum detection sensitivity and specificity. Sample enrichment was achieved by Oasis HLB solid-phase extraction cartridges. The quantitation limits of these compounds ranged from 5 to 10 ng/L in 1000-mL water samples. Recovery of the estrogenic chemicals in spiked various water samples ranged from 78 to 102% while relative standard deviation (RSD) ranged from 1 to 15%.