Publications by authors named "Oberemm A"

The marine biotoxin okadaic acid (OA) is produced by dinoflagellates and enters the human food chain by accumulating in the fatty tissue of filter-feeding shellfish. Consumption of highly contaminated shellfish can lead to diarrheic shellfish poisoning. However, apart from the acute effects in the intestine, OA can also provoke toxic effects in the liver, as it is able to pass the intestinal barrier into the blood stream.

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3-Chloro-1,2-propanediol (3-MCPD) and its fatty acid esters (FE) are present as contaminants in different processed foods. Based on the available toxicological data the potential risk of 3-MCPD and its FE to human health was assessed by risk assessment authorities, including the European Food Safety Authority (EFSA). Considering the available data, EFSA concluded that 3-MCPD is a non-genotoxic compound exhibiting secondary carcinogenic effects in rodents.

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Polycyclic aromatic hydrocarbons (PAHs) are among the chemicals with proven impact on workers' health. The use of human biomonitoring (HBM) to assess occupational exposure to PAHs has become more common in recent years, but the data generated need an overall view to make them more usable by regulators and policymakers. This comprehensive review, developed under the Human Biomonitoring for Europe (HBM4EU) Initiative, was based on the literature available from 2008-2022, aiming to present and discuss the information on occupational exposure to PAHs, in order to identify the strengths and limitations of exposure and effect biomarkers and the knowledge needs for regulation in the workplace.

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A number of human biomonitoring (HBM) studies have presented data on exposure to hexavalent chromium [Cr(VI)] and cadmium (Cd), but comparatively few include results on effect biomarkers. The latter are needed to identify associations between exposure and adverse outcomes (AOs) in order to assess public health implications. To support improved derivation of EU regulation and policy making, it is of great importance to identify the most reliable effect biomarkers for these heavy metals that can be used in HBM studies.

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Drug-induced liver injury (DILI) cannot be accurately predicted by animal models. In addition, currently available in vitro methods do not allow for the estimation of hepatotoxic doses or the determination of an acceptable daily intake (ADI). To overcome this limitation, an in vitro/in silico method was established that predicts the risk of human DILI in relation to oral doses and blood concentrations.

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Transcriptomics is developing into an invaluable tool in toxicology. The aim of this study was, using a transcriptomics approach, to identify genes that respond similar to many different chemicals (including drugs and industrial compounds) in both rat liver in vivo and in cultivated hepatocytes. For this purpose, we analyzed Affymetrix microarray expression data from 162 compounds that were previously tested in a concentration-dependent manner in rat livers in vivo and in rat hepatocytes cultivated in sandwich culture.

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The antihistaminic drug methapyrilene was withdrawn from the market in 1979 because of hepatocarcinogenicity in rats. Since then, the drug has been used as a model hepatotoxin especially for transcriptomic analyses using material from in vivo studies. Much less transcriptomics data are available from in vitro studies, and no studies have investigated proteomic effects of methapyrilene in vitro.

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2-monochloropropanediol (2-MCPD), 3-monochloropropanediol (3-MCPD) and their fatty acid esters have recently been identified as heat-induced contaminants in fat- and salt-containing foodstuff. Toxicity of 3-MCPD has been studied previously in some detail. Disturbance of glycolysis and cellular redox functions appear to be involved in 3-MCPD toxicity.

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2- and 3-monochloropropanediol (2-MCPD) and their fatty acid esters are food contaminants which are concomitantly formed upon thermal treatment of foodstuff containing fats and salt. Exposure to 2- or 3-MCPD thus results, for example, from refined vegetable oils, in instant meals or infant formula, as well as in cereals or pastries. The molecular mechanisms of 2-MCPD toxicity are poorly understood.

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The presence of nano-scaled particles in food and food-related products has drawn attention to the oral uptake of nanoparticles and their interactions with biological systems. In the present study, we used a toxicoproteomics approach to allow for the untargeted experimental identification and comparative analysis of cellular responses in rat liver after repeated-dose treatment with silver nanoparticles, ions, and the coating matrix used for particle stabilization. The proteomic analysis revealed treatment-related effects caused by exposure to silver in particulate and ionic form.

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Consumers are orally exposed to nanoparticulate or soluble species of the non-essential element silver due to its use in food contact materials or as a food additive. Potential toxicity of silver nanoparticles has gained special scientific attention. A fraction of ingested ionic or particulate silver is taken up in the intestine and transported to the liver, where it may induce oxidative stress and elicit subsequent adverse responses.

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The heat-induced food contaminant 3-monochloropropane-1,2-diol (3-MCPD) and its fatty acid esters exert nephrotoxicity in rodents. Previous studies including a non-targeted toxicoproteomics approach using samples from a 28-day oral toxicity study in rats with 10 mg/kg body weight (b.w.

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The chlorinated propanols 2- and 3-monochloropropanediol (MCPD), and their fatty acid esters have gained public attention due to their frequent occurrence as heat-induced food contaminants. Toxic properties of 3-MCPD in kidney and testis have extensively been characterized. Other 3-MCPD target organs include heart and liver, while 2-MCPD toxicity has been observed in striated muscle, heart, kidney, and liver.

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Data from a comparative proteomic analysis of three human breast epithelial cell lines are presented. M13SV1 cells and their tumorigenic derivatives M13SV1-R2-2 and M13SV1-R2-N1 were used. Proteomic data were obtained using 2-dimensional gel electrophoresis and subsequent identification of proteins by MALDI-TOF mass spectrometry.

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3-Monochloropropane-1,2-diol (3-MCPD) and 3-MCPD fatty acid esters are process contaminants in foodstuff which are generated during thermal treatment. Long-term exposure to 3-MCPD or 3-MCPD esters causes toxicity especially in kidney and testis. 3-MCPD esters are efficiently hydrolyzed in the gastrointestinal tract, suggesting that their toxicity is mediated by free 3-MCPD.

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Even although quite a number of studies have been performed so far to demonstrate nanoparticle-specific effects of substances in living systems, clear evidence of these effects is still under debate. The present study was designed as a comparative proteomic analysis of human intestinal cells exposed to a commercial silver nanoparticle reference material and ions from AgNO3. A two-dimensional gel electrophoresis/MALDI mass spectrometry (MS)-based proteomic analysis was conducted after 24-h incubation of differentiated Caco-2 cells with non-cytotoxic and low cytotoxic silver concentrations (2.

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3-Chloropropane-1,2-diol (3-MCPD) and its fatty acid esters are formed during thermal treatment of fat-containing foodstuff in the presence of salt. Toxicological studies indicate a carcinogenic potential of 3-MCPD, pointing to the kidney as the main target organ. It is assumed that the toxicological property of 3-MCPD esters is constituted by the release of 3-MCPD during digestion.

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Thermal treatment of foodstuff containing fats and salt promotes the formation of 3-chloropropane-1,2-diol (3-MCPD) and its fatty acid esters. 3-MCPD-exposed rats develop testicular lesions and Leydig cell tumors. 3-MCPD and 3-MCPD ester toxicity is thought to be caused by 3-MCPD and its metabolites, since 3-MCPD esters are hydrolyzed in the gut.

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A long-term goal of numerous research projects is to identify biomarkers for in vitro systems predicting toxicity in vivo. Often, transcriptomics data are used to identify candidates for further evaluation. However, a systematic directory summarizing key features of chemically influenced genes in human hepatocytes is not yet available.

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Cultivated hepatocytes represent a well-established in vitro system. However, the applicability of hepatocytes in toxicogenomics is still controversially discussed. Recently, an in vivo/in vitro discrepancy has been described, whereby the non-genotoxic rat liver carcinogen methapyrilene alters the expression of the metabolizing genes SULT1A1 and ABAT, as well as the DNA damage response gene GADD34 in vitro, but not in vivo.

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Although cultivated hepatocytes are widely used in the studies of drug metabolism, their application in toxicogenomics is considered as problematic, because previous studies have reported only little overlap between chemically induced gene expression alterations in liver in vivo and in cultivated hepatocytes. Here, we identified 22 genes that were altered in livers of rats after oral administration of the liver carcinogens aflatoxin B1 (AB1), 2-nitrofluorene (2-NF), methapyrilene (MP) or piperonyl-butoxide (PBO). The functions of the 22 genes have been classified into two groups.

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A common animal model of chemical hepatocarcinogenesis was used to examine the utility of transcriptomic and proteomic data to identify early biomarkers related to chemically induced carcinogenesis. N-nitrosomorpholine, a frequently used genotoxic model carcinogen, was applied via drinking water at 120 mg/L to male Wistar rats for 7 weeks followed by an exposure-free period of 43 weeks. Seven specimens of each treatment group (untreated control and 120 mg/L N-nitrosomorpholine in drinking water) were sacrificed at nine time points during and after N-nitrosomorpholine treatment.

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Recent studies have presented evidence that in vivo obtained gene expression data can be used for carcinogen classification, for instance to differentiate between genotoxic and non-genotoxic carcinogens. However, although primary rat hepatocytes represent a well-established in vitro system for drug metabolism and enzyme induction, they have not yet been systematically optimized for toxicogenomic studies. The latter may be confounded by the fact that cultured hepatocytes show strong spontaneous alterations in gene expression patterns.

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