Enhancing effect of taurine on CYP7A1 mRNA expression in Hep G2 cells.

Taurine has been reported to enhance cholesterol 7alpha-hydroxylase (CYP7A1) mRNA expression in animal models. However, no in vitro studies of this effect have been reported. The Hep G2 human hepatoma cell line has been recognized as a good model for studying the regulation of human CYP7A1. This work characterizes the effects of taurine on CYP7A1 mRNA levels of Hep G2 cells in a dose- and time-dependent manner. In the dose-dependent experiment, Hep G2 cells were treated with 0, 2, 10 or 20 mM taurine in the presence or absence of cholesterol 0.2 mM for 48 h. In the time-dependent experiment, Hep G2 cells were treated with 0 or 20 mM taurine for 4, 24 and 48 h with and without cholesterol 0.2 mM. Our data revealed that taurine showed time- and dose-response effects on CYP7A1 mRNA levels in Hep G2 cells. However, glycine - a structural analogue of taurine - did not have an effect on CYP7A1 gene expression. These results show that, in agreement to previous studies on animal models, taurine induces the mRNA levels of CYP7A1 in Hep G2 cells, which could enhance cholesterol conversion into bile acids. Also, Hep G2 cell line may be an appropriate model to study the effects of taurine on human cholesterol metabolism.

Objective pathological diagnosis of coal worker's pneumoconiosis.

Pertinent pathological features of lungs obtained at autopsies from 99 coal miners were compared with those observed in the lungs of 268 male town dwellers of comparable age who were not occupationally related to the coal mining or other industries at risk for development of pneumoconiosis. The degree of anthracotic pigment deposition and severity of type of pigmented lesion with its accompanying reticulum fiber formation and fibrosis were significantly greater in lungs of miners. There was a high degree of overlap in degree of pigment deposition, particularly those quantitated as grades 1 and 2 and in lesions regarded as types 1 and 2. The greatest divergence was observed for prevalence of nodular pulmonary lesions (type 4). There was also a considerable divergence in the type 3 alteration characterized by nonnodular aggregates of carbon-laden macrophages accompanied by minimal reactive fibrosis. It appears that an objective pathological diagnosis of coal workers' pneumoconiosis (CWP) can be rendered only by the demonstration of type 4 lesions. Approximately 25% of coal miners exhibited unequivocal features of CWP. No significant differences concerning incidence or types of emphysema or frequency of chronic cor pulmonale were encountered between the two populations.