[Show abstract][Hide abstract] ABSTRACT: In a recent study, magnetite was investigated for its potential to induce toxic effects and influence signalling pathways. It was clearly demonstrated that ROS formation leads to mitochondrial damage and genotoxic effects in A549 cells. Based on these findings, we wanted to elucidate the origin of magnetite-mediated ROS formation and its influence on the cell cycle of A549 and H1299 human lung epithelial cells. A concentration and size-dependent superoxide formation, measured by electron paramagnetic resonance (EPR), was observed. Furthermore, we could show that the GSH level decreased significantly after exposure to magnetite particles while catalase (CAT) activity was increased. These effects were also depending on particle size, albeit less pronounced than those observed with EPR. We were able to show that incubation of A549 cells prior to particle treatment with diphenyleneiodonium (DPI), a NADPH-oxidase (NOX) inhibitor, leads to decreased ROS formation, but this effect was not observed for the NOX inhibitor apocynin. Soluble iron does not contribute considerably to ROS production. Analysis of cell-cycle distribution revealed a pronounced sub-G1 peak, which cannot be linked to increased cell death. Western blot analysis did not show activation of p53 but upregulation of p21 in A549. Here, we were unexpectedly able to demonstrate that exposure to magnetite leads to p21-mediated G1-like arrest. This has been reported previously only for low concentrations of microtubule stabilisation drugs. Importantly, the arrested sub-G1 cells were viable and showed no caspase 3/7 activation.
Chemical Research in Toxicology 04/2013; · 4.19 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Reports on adverse health effects related to occupational exposure to toner powder are still inconclusive. Therefore, we have previously conducted an in vitro-study to characterize the genotoxic potential of three commercially available black printer toner powders in A549 lung cells. In these cell-based assays it was clearly demonstrated that the tested toner powders damage DNA and induce micronucleus (MN) formation. Here, we have studied the cytotoxic and proinflammatory potential of these three types of printer toner particles and the influence of ROS and NF-κB induction in order to unravel the underlying mechanisms. A549 cells were exposed to various concentrations of printer toner particle suspensions for 24 h. The toner particles were observed to exert significant cytotoxic effects in the WST-1 and neutral red (NR)-assays, although to a varying extent. Caspase 3/7 activity increased, while the mitochondrial membrane potential (MMP) was not affected. Particles of all three printer toner powders induced concentration-dependent formation of reactive oxygen species (ROS), as measured in the DCFH-DA assay. Furthermore, toner particle exposure enhanced interleukin-6 and interleukin-8 production, which is in agreement with activation of the transcription factor NF-κB in A549 cells shown by the electrophoretic mobility shift assay (EMSA). Therefore, it can be concluded that exposure of A549 lung cells to three selected printer toner powders caused oxidative stress through induction of ROS. Increased ROS formation may trigger genotoxic effects and activate proinflammatory pathways.
[Show abstract][Hide abstract] ABSTRACT: 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 PbSO4 (anglesite), ZnSO4•H2O (gunningite), and CaSO4 (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 PbSO4 and CaSO4 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 Electron Paramagnetic Resonance (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 CaSO4, whereas only slight effects could be found for PbSO4. Moreover, changes of cell cycle were observed for Zn sulfate and PbSO4. It could be shown further that Zn sulfate increased the nuclear factor kappa-B (NF-κB) DNA binding activity and activated c-Jun N-terminal kinases (JNK). During our TEM investigations, no effect on the appearance of the A549 cells exposed to CaSO4 compared to the non-exposed cells was observed, and in our experiments only one CaSO4 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 PbSO4, 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 the population living near such power plants.
Chemical Research in Toxicology 11/2012; · 4.19 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Ciprofloxacin (CIP), a broad-spectrum, second-generation fluoroquinolone, has frequently been found in hospital wastewaters and effluents of sewage treatment plants. CIP is scarcely biodegradable, has toxic effects on microorganisms and is photosensitive. The aim of this study was to assess the genotoxic potential of CIP in human HepG2 liver cells during photolysis.
Photolysis of CIP was performed in aqueous solution by irradiation with an Hg lamp, and transformation products were monitored by HPLC-MS/MS and by the determination of dissolved organic carbon (DOC). The cytotoxicity and genotoxicity of CIP and of the irradiated samples were determined after 24 h of exposure using the WST-1 assay and the in vitro micronucleus (MN) test in HepG2 cells.
The concentration of CIP decreased during photolysis, whereas the content of DOC remained unchanged. CIP and its transformation products were not cytotoxic towards HepG2 cells. A concentration-dependent increase of MN frequencies was observed for the parent compound CIP (lowest observed effect level, 1.2 μmol L(-1)). Furthermore, CIP and the irradiated samples were found to be genotoxic with a significant increase relative to the parent compound after 32 min (P < 0.05). A significant reduction of genotoxicity was found after 2 h of irradiation (P < 0.05).
Photolytic decomposition of aqueous CIP leads to genotoxic transformation products. This proves that irradiated samples of CIP are able to exert heritable genotoxic effects on human liver cells in vitro. Therefore, photolysis as a technique for wastewater treatment needs to be evaluated in detail in further studies, not only for CIP but in general.
Environmental Science and Pollution Research 12/2011; 19(5):1719-27. · 2.76 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Various publications indicate that the operation of laser printers and photocopiers may be associated with health effects due to the release of gaseous components and fine and ultrafine particles (UFP). However, only sparse studies are available that evaluate the possible exposure of office workers to printer emissions under real conditions. Therefore, the aim of our study was to assess the exposure of office workers to particulate matter released from laser printers and photocopiers.
Concentrations of fine particles and UFP were measured before, during, and after the operation of laser printing devices in 63 office rooms throughout Germany. Additionally, the particles were characterized by electron microscopy and energy-dispersive X-ray spectroscopy.
A significant increase of fine particles and UFP was identified in ambient workplace air during and after the printing processes. Particle fractions between 0.23 and 20 μm emitted by the office machines significantly affect particle mass concentrations while printing 500 pages, i.e., during the printing process, PM(0.23-20), PM(2.5), and PM(10) concentrations increased in 43 out of the evaluated 62 office rooms investigated. Additionally, a significant increase was observed in submicrometer particles, with median particle number concentrations of 6,503 particles/cm(3) before and 18,060 particles/cm(3) during the printing process.
Our data indicate that laser printers and photocopiers could be a relevant source of fine particles and particularly UFP in office rooms.
Environmental Science and Pollution Research 11/2011; 19(9):3840-9. · 2.76 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Exposure to emissions from laser printers during the printing process is commonplace worldwide, both in the home and workplace environment. In the present study, cytotoxic and genotoxic effects of the emission from five low to medium-throughput laser printers were investigated with respect to the release of ozone (O(3) ), volatile organic compounds (VOC), particulate matter (PM), and submicrometer particles (SMP) during standby and operation. Experiments were conducted in a 1 m(3) emission chamber connected to a Vitrocell® exposure system. Cytotoxicity was determined by the WST-1 assay and genotoxicity by the micronucleus test in human A549 lung cells. The five laser printers emitted varying but generally small amounts of O(3) , VOC, and PM. VOC emissions included 13 compounds with total VOC concentrations ranging from 95 to 280 μg/m(3) (e.g., 2-butanone, hexanal, m,p-xylene, and o-xylene). Mean PM concentrations were below 2.4 μg/m(3). SMP number concentration levels during standby ranged from 9 to 26 particles/cm(3). However, three of the printers generated a 90 to 16 × 10(3) -fold increase of SMP during the printing process (maximum 294,460 particles/cm(3)). Whereas none of the printer emissions were found to cause cytotoxicity, emissions from two printers induced formation of micronuclei (P < 0.001), thus providing evidence for genotoxicity. As yet, differences in biological activity cannot be explained on the basis of the specific emission characteristics of the different printers. Because laser printing technology is widely used, studies with additional cytogenetic endpoints are necessary to confirm the DNA-damaging potency and to identify emission components responsible for genotoxicity.
Environmental and Molecular Mutagenesis 11/2011; 53(2):125-35. · 2.55 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Pinewood (Pinus ssp.) is widely used for furniture and building purposes. However, despite its widespread use, information on possible human
sensory irritations and pulmonary effects caused by exposure to volatile organic compounds (VOC) emitted from pinewood is
sparse. For this purpose, (1) sensory irritation of eyes, nose and throat, (2) lung function parameters (FVC, FEV1), (3) exhaled nitrogen oxide (NO) concentration, (4) eye blink frequency, and (5) sensory evaluation (using the SD method)
were investigated before, after, and partly during exposure of human volunteers to emissions from pinewood panels. Fifteen
healthy nonsmokers were exposed for 2 h under controlled conditions to VOCs emitted from pinewood panels in a 48 m3 test chamber. VOC concentrations were about 5 mg/ m3 (loading rate, 1 m2/m3), 8 mg/m3 (loading rate, 2 m2/m3), and 13 mg/m3 (loading rate, 3 m2/m3), respectively. Terpene and aldehyde exposure concentrations ranged from about 3.50 ± 0.51 mg/m3 and 0.07 ± 0.008 mg/m3, 5.00 ± 0.95 mg/ m3, and 0.20 ± 0.02 mg/m3 or 9.51 ± 1.10 mg/m3 and 0.21 ± 0.04 mg/m3 for loading rates of 1, 2, and 3 m2/m3, respectively. The emissions consisted predominantly of α-pinene and δ3-carene. No concentration-dependent effects before or after exposure to the emissions were measured with respect to sensory
irritation, pulmonary function, exhaled NO, and eye blink frequency. Only the odor of the emissions was perceived by the study
subjects, rated as being closer to “pleasant” than to “unpleasant.” In conclusion, the results of our study suggest that short-term
exposure to high VOC concentrations, even up to 13 mg/m3, released from pine wood does not elicit sensory irritation or pulmonary effects in healthy humans under controlled conditions.
Journal of Wood Science 10/2011; · 0.83 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Airborne particulate matter (PM) of varying size and composition is known to cause health problems in humans. The iron oxide Fe(3)O(4) (magnetite) may be a major anthropogenic component in ambient PM and is derived mainly from industrial sources. In the present study, we have investigated the effects of four different size fractions of magnetite on signaling pathways, free radical generation, cytotoxicity, and genotoxicity in human alveolar epithelial-like type-II cells (A549). The magnetite particles used in the exposure experiments were characterized by mineralogical and chemical techniques. Four size fractions were investigated: bulk magnetite (0.2-10 μm), respirable fraction (2-3 μm), alveolar fraction (0.5-1.0 μm), and nanoparticles (20-60 nm). After 24 h of exposure, the A549 cells were investigated by transmission electron microscopy (TEM) to study particle uptake. TEM images showed an incorporation of magnetite particles in A549 cells by endocytosis. Particles were found as agglomerates in cytoplasm-bound vesicles, and few particles were detected in the cytoplasm but none in the nucleus. Increased production of reactive oxygen species (ROS), as determined by the 2',7'-dichlorfluorescein-diacetate assay (DCFH-DA), as well as genotoxic effects, as measured by the cytokinesis block-micronucleus test and the Comet assay, were observed for all of the studied fractions after 24 h of exposure. Moreover, activation of c-Jun N-terminal kinases (JNK) without increased nuclear factor kappa-B (NF-κB)-binding activity but delayed IκB-degradation was observed. Interestingly, pretreatment of cells with magnetite and subsequent stimulation with the pro-inflammatory cytokine tumor necrosis factor-alpha (TNFα) led to a reduction of NF-κB DNA binding compared to that in stimulation with TNFα alone. Altogether, these experiments suggest that ROS formation may play an important role in the genotoxicity of magnetite in A549 cells but that activation of JNK seems to be ROS-independent.
Chemical Research in Toxicology 07/2011; 24(9):1460-75. · 4.19 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Until now, the adverse effects of toner powders on humans have been considered to be minimal. However, several recent reports have suggested possible significant adverse health effects from toner dust inhalation. The aim of this study was to evaluate the genotoxic potential of black toner powders in vitro. For the study of DNA damage, A549 cells were exposed to toner-powder suspensions and to their DMSO extracts, and then subjected to the comet assay and to the in-vitro cytokinesis block micronucleus test (CB-MNvit). Cytotoxic effects of the toner samples were assessed by the erythrosin B assay. Furthermore, size, shape, and composition of the toner powders were investigated. None of the three toner powders or their DMSO extracts reduced cell viability; however, they did induce DNA damage and formed micronuclei at concentrations from 80 to 400 μg cm(-2) , although to a varying extent. All toner powders contain considerable amounts of the pigments carbon black and magnetite (Fe(3) O(4) ) as well as small amounts of polycyclic aromatic hydrocarbons (PAHs). The overall results of our in-vitro study suggest that the investigated toner-powder samples are not cytotoxic but genotoxic. From the results of the physical and chemical characterization, we conclude that metals and metalloids as components of magnetite, or PAHs as components of the carbon-bearing material, are responsible for the genotoxic effects. Further research is necessary to determine the relevance of these in-vitro observations for private and occupational toner powder exposure.
Environmental and Molecular Mutagenesis 05/2011; 52(4):296-309. · 2.55 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Due to the reduction of air change rates in low-energy houses, the contribution to indoor air quality of volatile organic compounds (VOCs) emitting from oriented strand boards (OSB) has become increasingly important. The aim of this study was to evaluate sensory irritations, pulmonary effects and odor annoyance of emissions from OSB in healthy human volunteers compared to clean air. Twenty-four healthy non-smokers were exposed to clean air and OSB emissions for 2 h under controlled conditions in a 48 m(3) test chamber at three different time points: to fresh OSB panels and to the same panels after open storage for 2 and 8 weeks. Chemosensory irritation, exhaled nitric oxide (NO) concentration, eye blink frequency, lung function and subjective perception of irritation of eyes, nose and throat were examined before, during and after exposure. Additionally, olfactory perception was investigated. Total VOC exposure concentrations reached 8.9 ± 0.8 mg/m(3) for the fresh OSB panels. Emissions consisted predominantly of α-pinene, Δ(3)-carene and hexanal. Two-hour exposure to high VOC concentrations revealed no irritating or pulmonary effects. All the subjective ratings of discomfort were at a low level and the medians did not exceed the expression 'hardly at all.' Only the ratings for smell of emissions increased significantly during exposure in comparison to clean air. In conclusion, exposure of healthy volunteers to OSB emissions did not elicit sensory irritations or pulmonary effects up to a VOC concentration of about 9 mg/m(3). Sensory intensity of OSB emissions in the chamber air was rated as 'neutral to pleasant.'
Human & Experimental Toxicology 11/2010; 30(9):1204-21. · 1.41 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Epidemiological studies have shown that respirable exposure to emitted cement particulate matter is associated with adverse health risk for human. The underlying mechanisms, however, are poorly understood. To examine the effect of cement, nine blinded cement-related particulates (<10 μm) were assessed with regard to their induction of the proinflammatory cytokines IL-6 and IL-8 in human primary epithelial cells (pEC) from oropharyngeal mucosa as well as from nonsmall-cell lung carcinoma (non-SCLC) cells A549. It was demonstrated that the cement specimens did not act cytotoxic as assessed by the lactate dehydrogenase (LDH) assay. The basal and IL-1β-induced IL-8 expression was suppressed, in contrast to an unchanged IL-6. At the transcript level the basal and induced IL-6 and IL-8 gene expression was not influenced by cement dust. To discover the mechanism by which cement influenced the IL-8 expression the following experiments were performed. Submerse exposure experiments have shown that the release of IL-8 was suppressed by cement dust. Furthermore, the incubation of IL-8 with cement-related specimens under cell-free condition led to a loss of immunoreactive IL-8. An immunological masking of IL-8 by free soluble components of respiratory epithelial cells was excluded. Thus, the decrease of IL-8 protein content after cement exposure seems to be a result of the adsorption of IL-8 protein to cement particles and the inhibition of IL-8 release. In conclusion, due to absent cytotoxic and inflammatory effects of cement-related specimens in both human pEC and A549 cell models it remains open how cement exposure may lead to the respiratory adverse effects in humans.
[Show abstract][Hide abstract] ABSTRACT: Synthetic musk compounds are widely used as fragrance ingredients in many consumer products. Little is known about their accumulation in humans and especially in older persons. In this study, we determined concentrations of 11 synthetic musks in women above fifty years and compared the results with earlier results from samples of young females. Blood was taken from 53 women above 50 years of age, visiting outpatients of the Department of Angiology at the Hanusch-Krankenhaus in Vienna, Austria. The used analytical methods consist of an extraction and clean-up step and a chromatographic analysis by GC/MS. Tonalide-D3 was used as recovery standard in all samples. Hexachlorobenzene (13)C(6) was used as internal standard. Study participants also completed a questionnaire on the use of cosmetics, about nutrition and other life-style aspects. The two substances which could be detected in higher percentages of the blood plasma samples were galaxolide (89 percent, maximum concentration 6900 ng/L) and musk xylene (62 percent, maximum concentration 190 ng/L). Regression analysis revealed a significant association of galaxolide concentration with frequent use of perfumes, deodorants and shampoos. Frequent use of soaps and fabric softener was associated with higher plasma concentrations of musk xylene. Nutrition habits, skin type, body mass index or surface area were not related to plasma concentration of these musk compounds. From the study group investigated older persons showed higher plasma concentrations. These findings could be due to the higher use of lotions and crèmes on face and hands and a more frequent use of skin care products because older persons reported more frequently dry skin. In addition, physiological aging related changes might be responsible for higher dermal absorption of synthetic musks. These results indicate that more focus on aging tissues is needed.
International journal of hygiene and environmental health 03/2010; 213(2):124-30. · 2.64 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Due to the massive reduction of air-change rates in modern, energy-saving houses and dwellings, the contribution of volatile organic compound (VOCs) emissions from wood-based materials to indoor air quality has become increasingly important. To evaluate toxicity of VOC mixtures typically emitted from pine wood and oriented strand boards (OSB) and their main constituents (selected terpenes and aldehydes), cytotoxicity and genotoxicity were investigated in human A549 lung cells. To facilitate exposure directly via gas phase, a 250 L emission chamber was combined with a Vitrocell exposure system. VOC exposure concentrations were measured by GC/MSD. Biological effects were determined after an exposure time of 1h by measuring cytotoxicity (erythrosine B staining) and genotoxicity (comet assay). Neither cytotoxic nor genotoxic effects were observed for VOC mixtures emitted from pine wood or OSB at loading factors of approximately 13 m(2)/m(3) (worst case conditions) of the panels (with maximum VOC levels of about 80 mg/m(3)) in comparison to clean air. While alpha-pinene and Delta(3)-carene did not induce toxic effects even at exposure concentrations of up to 1800 mg/m(3) and 600 mg/m(3), respectively, hexanal showed a cytotoxic effect at 2000 mg/m(3). The alpha,beta-unsaturated aldehydes 2-heptenal and 2-octenal caused genotoxic effects in concentrations exceeding 100mg/m(3) and 40 mg/m(3), respectively. In conclusion, high concentrations of VOCs and VOC mixtures emitted from pine wood and OSB did not lead to adverse effects in A549 human lung cells even at concentrations 10(2) to 10(5)-fold higher than those found in normal indoor air. Attention must be paid to mutagenic and possibly carcinogenic alpha,beta-unsaturated aldehydes.