Cellular uptake and toxic effects of fine and ultrafine metal-sulfate particles in human A549 lung epithelial cells.

Ambient airborne particulate matter is known to cause various adverse health effects in humans. In a recent study on the environmental impacts of coal and tire combustion in a thermal power station, fine crystals of PbSO(4) (anglesite), ZnSO(4)·H(2)O (gunningite), and CaSO(4) (anhydrite) were identified in the stack emissions. Here, we have studied the toxic potential of these sulfate phases as particulates and their uptake in human alveolar epithelial cells (A549). Both PbSO(4) and CaSO(4) yielded no loss of cell viability, as determined by the WST-1 and NR assays. In contrast, a concentration-dependent increase in cytotoxicity was observed for Zn sulfate. For all analyzed sulfates, an increase in the production of reactive oxygen species (ROS), assessed by the DCFH-DA assay and EPR, was observed, although to a varying extent. Again, Zn sulfate was the most active compound. Genotoxicity assays revealed concentration-dependent DNA damage and induction of micronuclei for Zn sulfate and, to a lower extent, for CaSO(4), whereas only slight effects could be found for PbSO(4). Moreover, changes of the cell cycle were observed for Zn sulfate and PbSO(4). It could be shown further that Zn sulfate increased the nuclear factor kappa-B (NF-κB) DNA binding activity and activated JNK. During our TEM investigations, no effect on the appearance of the A549 cells exposed to CaSO(4) compared to the nonexposed cells was observed, and in our experiments, only one CaSO(4) particle was detected in the cytoplasm. In the case of exposure to Zn sulfate, no particles were found in the cytoplasm of A549 cells, but we observed a concentration-dependent increase in the number and size of dark vesicles (presumably zincosomes). After exposure to PbSO(4), the A549 cells contained isolated particles as well as agglomerates both in vesicles and in the cytoplasm. Since these metal-sulfate particles are emitted into the atmosphere via the flue gas of coal-fired power stations, they may be globally abundant. Therefore, our study is of direct relevance to populations living near such power plants.

Identifying elderly women with osteoporosis by spinal dual X-ray absorptiometry, calcaneal quantitative ultrasound and spinal quantitative computed tomography: a comparative study.

The ability of spinal dual x-ray absorptiometry (DXA), calcaneal quantitative ultrasound (QUS) and spinal quantitative computed tomography (QCT) to identify women with osteoporosis within the GISELA study was evaluated in 43 women, aged 62-87 years. Osteoporosis was defined as a T-score below or equal to -2.5 using DXA (femoral neck). To determine the performance of each method, the sensitivity, specificity and area under the curve (by means of a receiver operating characteristic [ROC] analysis) were calculated. The median T-scores from the measurements differed significantly (p < 0.0001). DXA (spine) identified 75% of women with osteoporosis; QUS and QCT identified 100%. The specificity was 89% for DXA (spine), 66% for QUS and 29% for QCT. ROC analysis showed that all three methods are qualified to identify women with osteoporosis; however, the different sensitivities and specificities of the methods, as well as the thresholds used for diagnosing osteoporosis have to be considered.