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Lin S, Yang Z, Zhang X, Bian Z, Cai Z. Hippocampal metabolomics reveals 2,3,7,8-tetrachlorodibenzo-p-dioxin toxicity associated with ageing in Sprague-Dawley rats. Talanta 2011; 85:1007-12. [PMID: 21726731 DOI: 10.1016/j.talanta.2011.05.007] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2011] [Revised: 05/01/2011] [Accepted: 05/05/2011] [Indexed: 10/18/2022]
Abstract
Metabolomics, the exponentially developing technique, could provide a systemic mapping in toxicology by directly measuring small molecular metabolites. 2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) was found to be neurotoxic in mammalian animals. In this study, we employed liquid chromatography/quadrupole time-of-flight mass spectrometry for non-targeted analysis of metabolic profiling in hippocampal sample sets of the rats exposed to TCDD. Hippocampal metabolome from different ages of the healthy rats (4-week, 12-week and 20-week) was also deciphered. The relationship between the two tested cases was unlocked to delineate TCDD toxicity associated with ageing. Tandem mass spectrometry fragmentation in conjunction with metabolic database searching and compared to authentic standards was utilized for metabolite identification. As a consequence, the reduced levels of phenylalanine and leucine/isoleucine as well as the up-regulation of inosine and hypoxanthine were highlighted for understanding of TCDD toxicity related to age in rats and the trajectory was depicted by principal components analysis.
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Affiliation(s)
- Shuhai Lin
- Department of Chemistry, Hong Kong Baptist University, Hong Kong, China
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Sergeev AV, Carpenter DO. Geospatial patterns of hospitalization rates for stroke with comorbid hypertension in relation to environmental sources of persistent organic pollutants: results from a 12-year population-based study. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2011; 18:576-585. [PMID: 20938749 DOI: 10.1007/s11356-010-0399-7] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/31/2009] [Accepted: 09/27/2010] [Indexed: 05/30/2023]
Abstract
PURPOSE Recent evidence indicates that exposure to persistent organic pollutants (POPs) is emerging as an important risk factor for atherosclerosis-related diseases, including stroke. Hypertension (HTN) is a major risk factor for stroke, and some studies suggest that exposure to POPs is also a risk factor for HTN. We hypothesized that POPs increase the environmental burden of stroke with comorbid HTN. METHODS A population-based study of hospitalization rates for stroke with comorbid HTN in populations presumably exposed to POPs, based on the zip code of residence, was conducted. Data on hospitalizations for stroke with comorbid HTN were obtained from the New York Statewide Planning and Research Cooperative System for 1993-2004. Relative risks, with 95% confidence intervals (RR, 95% CI), of hospitalization were estimated by multiple Poisson regression analysis. RESULTS RR of hospitalization for stroke with comorbid HTN was 13.4% higher in populations residing in zip codes containing or abutting environmental sources of POPs (RR = 1.134; 95% CI, 1.036-1.241; p = 0.006). Also, hospitalization rates were significantly higher in males than in females (RR = 1.397; 95% CI, 1.357-1.437; p < 0.001), in African Americans than in Caucasians (RR = 3.902; 95% CI, 3.617-4.208; p < 0.001), and in older age groups (p for trend < 0.001). These statistically significant findings of the effect of demographic factors are highly consistent with the current knowledge of stroke and serve as indirect quality indicators for our model. CONCLUSIONS Results of our study support the hypothesis that exposure to POPs increases the environmental burden of both stroke and HTN.
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Affiliation(s)
- Alexander V Sergeev
- Department of Social and Public Health, Ohio University, Grover Center W343, Athens, OH 45701, USA.
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Dioxin exposure of human CD34+ hemopoietic cells induces gene expression modulation that recapitulates its in vivo clinical and biological effects. Toxicology 2011; 283:18-23. [DOI: 10.1016/j.tox.2011.01.025] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2010] [Revised: 01/25/2011] [Accepted: 01/28/2011] [Indexed: 11/22/2022]
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Omiecinski CJ, Vanden Heuvel JP, Perdew GH, Peters JM. Xenobiotic metabolism, disposition, and regulation by receptors: from biochemical phenomenon to predictors of major toxicities. Toxicol Sci 2011; 120 Suppl 1:S49-75. [PMID: 21059794 PMCID: PMC3145385 DOI: 10.1093/toxsci/kfq338] [Citation(s) in RCA: 240] [Impact Index Per Article: 18.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2010] [Accepted: 11/01/2010] [Indexed: 02/07/2023] Open
Abstract
To commemorate the 50th anniversary of the Society of Toxicology, this special edition article reviews the history and current scope of xenobiotic metabolism and transport, with special emphasis on the discoveries and impact of selected "xenobiotic receptors." This overall research realm has witnessed dynamic development in the past 50 years, and several of the key milestone events that mark the impressive progress in these areas of toxicological sciences are highlighted. From the initial observations regarding aspects of drug metabolism dating from the mid- to late 1800's, the area of biotransformation research witnessed seminal discoveries in the mid-1900's and onward that are remarkable in retrospect, including the discovery and characterization of the phase I monooxygenases, the cytochrome P450s. Further research uncovered many aspects of the biochemistry of xenobiotic metabolism, expanding to phase II conjugation and phase III xenobiotic transport. This led to hallmark developments involving integration of genomic technologies to elucidate the basis for interindividual differences in response to xenobiotic exposures and discovery of nuclear and soluble receptor families that selectively "sense" the chemical milieu of the mammalian cell and orchestrate compensatory changes in gene expression programming to accommodate complex xenobiotic exposures. This review will briefly summarize these developments and investigate the expanding roles of xenobiotic receptor biology in the underlying basis of toxicological response to chemical agents.
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Affiliation(s)
- Curtis J Omiecinski
- Department of Veterinary and Biomedical Sciences, Center for Molecular Toxicology and Carcinogenesis, Penn State University, University Park, Pennsylvania 16802, USA.
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Abstract
Dioxins and Human ToxicityThe term dioxins usually refers to polychlorinated dibenzo-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs). As 2,3,7,8-tetrachloro-dibenzo-p-dioxin (TCDD) has the highest toxic potential, the toxic potentials of other PCDDs and PCDFs are defined in comparison with it. Human exposure to dioxins can be environmental (background), occupational, or accidental pollution. In the human body, dioxins are in part metabolised and eliminated, and the rest is stored in body fat. People vary in their capacity to eliminate TCDD, but it is also dose-dependent; the elimination rate is much faster at higher than lower levels. The liver microsomal P4501A1 enzyme oxygenates lipophilic chemicals such as dioxins. It is encoded by the CYP1A1 gene. Cytosolic aryl hydrocarbon receptor (AhR) mediates their carcinogenic action. It binds to dioxin, translocates to nucleus and together with hydrocarbon nuclear translocator (ARNT) and xenobiotic responsive element (XRE) increases the expression of CYP1A1.Dioxins are classified as known human carcinogens, but they also cause noncancerous effects like atherosclerosis, hypertension, and diabetes. Long-term exposures to dioxins cause disruption of the nervous, immune, reproductive, and endocrine system. Short-term exposure to high levels impairs the liver function and causes chloracne. The most sensitive population to dioxin exposure are the foetuses and infants.A large number of health effects have been documented in the scientific literature, and they all place dioxins among the most toxic chemicals known to man.
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Kawano Y, Nishiumi S, Tanaka S, Nobutani K, Miki A, Yano Y, Seo Y, Kutsumi H, Ashida H, Azuma T, Yoshida M. Activation of the aryl hydrocarbon receptor induces hepatic steatosis via the upregulation of fatty acid transport. Arch Biochem Biophys 2010; 504:221-7. [PMID: 20831858 DOI: 10.1016/j.abb.2010.09.001] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2010] [Accepted: 09/01/2010] [Indexed: 10/19/2022]
Abstract
The aryl hydrocarbon receptor (AHR) is a basic helix-loop-helix/Per-ARNT-Sim domain transcription factor, which is activated by various xenobiotic ligands. AHR is known to be abundant in liver tissue and to be associated with hepatic steatosis. However, it has not yet been elucidated how the activation of AHR promotes hepatic steatosis. The aim of this study is to clarify the role of AHR in hepatic steatosis. The intraperitoneal injection of 3-methylcholanthrene (3MC), a potent AHR ligand, into C57BL/6J mice significantly increased the levels of triglycerides and six long-chain monounsaturated fatty acids in the livers of mice, resulting in hepatic microvesicular steatosis. 3MC significantly enhanced the expression level of fatty acid translocase (FAT), a factor regulating the uptake of long-chain fatty acids into hepatocytes, in the liver. In an in vitro experiment using human hepatoma HepG2 cells, 3MC increased the expression level of FAT, and the downregulation of AHR by AHR siRNA led to the suppression of 3MC-induced FAT expression. In addition, the mRNA level of peroxisome proliferator-activated receptor (PPAR) α, an upstream factor of FAT, was increased in the livers of 3MC-treated mice. Taking together, AHR activation induces hepatic microvesicular steatosis by increasing the expression level of FAT.
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Affiliation(s)
- Yuki Kawano
- Department of Internal Medicine, Kobe University Graduate School of Medicine, Japan
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Lim S, Cho YM, Park KS, Lee HK. Persistent organic pollutants, mitochondrial dysfunction, and metabolic syndrome. Ann N Y Acad Sci 2010; 1201:166-76. [PMID: 20649553 DOI: 10.1111/j.1749-6632.2010.05622.x] [Citation(s) in RCA: 68] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
The number of individuals with metabolic syndrome is increasing worldwide, constituting a major social problem in many countries. Recently, epidemiological and experimental studies have associated insulin resistance or type 2 diabetes with elevated body burdens of persistent organic pollutants (POPs). It has been proposed that mitochondrial dysfunction plays a key role in this association. Mitochondrial DNA abnormalities are known to cause pancreas beta cell damage, insulin resistance, and diabetes mellitus. Recently, much evidence has emerged showing that environmental toxins, including POPs, affect mitochondrial function and subsequently induce insulin resistance. In this review, we present a novel concept in which metabolic syndrome is the result of mitochondrial dysfunction, which in turn is caused by exposure to POPs. The potential mechanism including POPs for mitochondrial dysfunction on metabolic syndrome is also discussed. We propose that the mitochondrial paradigm for the etiology of metabolic syndrome will facilitate the prevention and treatment of this major health problem.
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Affiliation(s)
- Soo Lim
- Department of Internal Medicine, Seoul National University College of Medicine, Seoul, Korea
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Alexeyenko A, Wassenberg DM, Lobenhofer EK, Yen J, Linney E, Sonnhammer ELL, Meyer JN. Dynamic zebrafish interactome reveals transcriptional mechanisms of dioxin toxicity. PLoS One 2010; 5:e10465. [PMID: 20463971 PMCID: PMC2864754 DOI: 10.1371/journal.pone.0010465] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2009] [Accepted: 03/17/2010] [Indexed: 01/09/2023] Open
Abstract
Background In order to generate hypotheses regarding the mechanisms by which 2,3,7,8-tetrachlorodibenzo-p-dioxin (dioxin) causes toxicity, we analyzed global gene expression changes in developing zebrafish embryos exposed to this potent toxicant in the context of a dynamic gene network. For this purpose, we also computationally inferred a zebrafish (Danio rerio) interactome based on orthologs and interaction data from other eukaryotes. Methodology/Principal Findings Using novel computational tools to analyze this interactome, we distinguished between dioxin-dependent and dioxin-independent interactions between proteins, and tracked the temporal propagation of dioxin-dependent transcriptional changes from a few genes that were altered initially, to large groups of biologically coherent genes at later times. The most notable processes altered at later developmental stages were calcium and iron metabolism, embryonic morphogenesis including neuronal and retinal development, a variety of mitochondria-related functions, and generalized stress response (not including induction of antioxidant genes). Within the interactome, many of these responses were connected to cytochrome P4501A (cyp1a) as well as other genes that were dioxin-regulated one day after exposure. This suggests that cyp1a may play a key role initiating the toxic dysregulation of those processes, rather than serving simply as a passive marker of dioxin exposure, as suggested by earlier research. Conclusions/Significance Thus, a powerful microarray experiment coupled with a flexible interactome and multi-pronged interactome tools (which are now made publicly available for microarray analysis and related work) suggest the hypothesis that dioxin, best known in fish as a potent cardioteratogen, has many other targets. Many of these types of toxicity have been observed in mammalian species and are potentially caused by alterations to cyp1a.
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Affiliation(s)
- Andrey Alexeyenko
- Stockholm Bioinformatics Centre, Stockholm University, Stockholm, Sweden
| | - Deena M. Wassenberg
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, North Carolina, United States of America
| | | | - Jerry Yen
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, North Carolina, United States of America
| | - Elwood Linney
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, North Carolina, United States of America
| | | | - Joel N. Meyer
- Nicholas School of the Environment, Duke University, Durham, North Carolina, United States of America
- * E-mail:
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Han SG, Eum SY, Toborek M, Smart E, Hennig B. Polychlorinated biphenyl-induced VCAM-1 expression is attenuated in aortic endothelial cells isolated from caveolin-1 deficient mice. Toxicol Appl Pharmacol 2010; 246:74-82. [PMID: 20406653 DOI: 10.1016/j.taap.2010.04.009] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2010] [Revised: 04/09/2010] [Accepted: 04/12/2010] [Indexed: 12/13/2022]
Abstract
Exposure to environmental contaminants, such as polychlorinated biphenyls (PCBs), is a risk factor for the development of cardiovascular diseases such as atherosclerosis. Vascular cell adhesion molecule-1 (VCAM-1) is a critical mediator for adhesion and uptake of monocytes across the endothelium in the early stages of atherosclerosis development. The upregulation of VCAM-1 by PCBs may be dependent on functional membrane domains called caveolae. Caveolae are particularly abundant in endothelial cell membranes and involved in trafficking and signal transduction. The objective of this study was to investigate the role of caveolae in PCB-induced endothelial cell dysfunction. Primary mouse aortic endothelial cells (MAECs) isolated from caveolin-1-deficient mice and background C57BL/6 mice were treated with coplanar PCBs, such as PCB77 and PCB126. In addition, siRNA gene silencing technique was used to knockdown caveolin-1 in porcine vascular endothelial cells. In MAECs with functional caveolae, VCAM-1 protein levels were increased after exposure to both coplanar PCBs, whereas expression levels of VCAM-1 were not significantly altered in cells deficient of caveolin-1. Furthermore, PCB-induced monocyte adhesion was attenuated in caveolin-1-deficient MAECs. Similarly, siRNA silencing of caveolin-1 in porcine endothelial cells confirmed the caveolin-1-dependent VCAM-1 expression. Treatment of cells with PCB77 and PCB126 resulted in phosphorylation of extracellular signal-regulated kinase-1/2 (ERK1/2), and pharmacological inhibition of ERK1/2 diminished the observed PCB-induced increase in monocyte adhesion. These findings suggest that coplanar PCBs induce adhesion molecule expression, such as VCAM-1, in endothelial cells, and that this response is regulated by caveolin-1 and functional caveolae. Our data demonstrate a critical role of functional caveolae in the activation and dysfunction of endothelial cells by coplanar PCBs.
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Affiliation(s)
- Sung Gu Han
- Molecular and Cell Nutrition Laboratory, College of Agriculture, University of Kentucky, Lexington, KY 40536, USA
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Vinken M, Doktorova T, Decrock E, Leybaert L, Vanhaecke T, Rogiers V. Gap junctional intercellular communication as a target for liver toxicity and carcinogenicity. Crit Rev Biochem Mol Biol 2009; 44:201-22. [PMID: 19635038 DOI: 10.1080/10409230903061215] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Direct communication between hepatocytes, mediated by gap junctions, constitutes a major regulatory platform in the control of liver homeostasis, ranging from hepatocellular proliferation to hepatocyte cell death. Inherent to this pivotal task, gap junction functionality is frequently disrupted upon impairment of the homeostatic balance, as occurs during liver toxicity and carcinogenicity. In the present paper, the deleterious effects of a number of chemical and biological toxic compounds on hepatic gap junctions are discussed, including environmental pollutants, biological toxins, organic solvents, pesticides, pharmaceuticals, peroxides, metals and phthalates. Particular attention is paid to the molecular mechanisms that underlie the abrogation of gap junction functionality. Since hepatic gap junctions are specifically targeted by tumor promoters and epigenetic carcinogens, both in vivo and in vitro, inhibition of gap junction functionality is considered as a suitable indicator for the detection of nongenotoxic hepatocarcinogenicity.
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Affiliation(s)
- Mathieu Vinken
- Department of Toxicology, Faculty of Medicine and Pharmacy, Vrije Universiteit Brussel, Brussels, Belgium.
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Jung JE, Moon JY, Ghil SH, Yoo BS. 2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) inhibits neurite outgrowth in differentiating human SH-SY5Y neuroblastoma cells. Toxicol Lett 2009; 188:153-6. [DOI: 10.1016/j.toxlet.2009.04.004] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2008] [Revised: 03/30/2009] [Accepted: 04/02/2009] [Indexed: 10/20/2022]
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Pohjanvirta R. Transgenic mouse lines expressing rat AH receptor variants — A new animal model for research on AH receptor function and dioxin toxicity mechanisms. Toxicol Appl Pharmacol 2009; 236:166-82. [DOI: 10.1016/j.taap.2009.01.005] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2008] [Revised: 01/09/2009] [Accepted: 01/12/2009] [Indexed: 11/25/2022]
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2,3,7,8-TCDD neurotoxicity in neuroblastoma cells is caused by increased oxidative stress, intracellular calcium levels, and tau phosphorylation. Toxicology 2009; 255:65-71. [DOI: 10.1016/j.tox.2008.10.006] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2008] [Revised: 10/07/2008] [Accepted: 10/07/2008] [Indexed: 12/22/2022]
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Pelclová D, Prázny M, Skrha J, Fenclová Z, Kalousová M, Urban P, Navrátil T, Senholdová Z, Smerhovsky Z. 2,3,7,8-TCDD exposure, endothelial dysfunction and impaired microvascular reactivity. Hum Exp Toxicol 2008; 26:705-13. [PMID: 17984141 DOI: 10.1177/0960327107083971] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Vascular function was examined in subjects with long-term high level of serum 2,3,7,8-tetrachlorodibenzo- p-dioxin (TCDD) during their follow-up visits. Their earlier mean peak TCDD level at the time of exposure in 1965-1968 was estimated in the range of 3300-74 000 pg/g lipids. Ten former pesticide production workers heavily exposed to TCDD (age 57 +/- 2 years, TCDD about 170 pg/g lipids) were examined in 2001. Extended group of 15 TCDD-exposed men (age 59 +/- 3 years, TCDD about 130 pg/g lipids) underwent the same examination in 2004. Findings were compared with a control group of 14 healthy men (age 54 +/- 2 years). Skin microvascular reactivity (MVR) was measured by laser Doppler perfusion monitoring in the forearm during post-occlusive reactive hyperemia (PORH) and thermal hyperemia (TH). Several parameters of MVR in men exposed to TCDD were significantly impaired, compared with the control group and further progression of the impairment of MVR has been observed between years 2001 and 2004. Serum concentration of E-selectin and inhibitor of tissue plasminogen activator 1 (PAI-1) was significantly higher in exposed subjects (56.0 +/- 18.4 ng/mL versus 40.0 +/- 12.0 ng/mL, P = 0.022 and 90.9 +/- 33.3 ng/mL versus 45.0 +/- 18.0, P = 0.002, respectively). In addition, PORH in the forearm was significantly negatively associated with SOD activity (r = -0.77, P = 0.009) as well as the velocity of perfusion increase during TH (r = -0.68, P = 0.03) and TH% (r = -0.78, P = 0.008). Our data document the presence of endothelial dysfunction in TCDD-exposed men.
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Affiliation(s)
- Daniela Pelclová
- Department of Occupational Medicine, 1st Medical Faculty, Charles University and General University Hospital, Na Bojisti 1, Prague, Czech Republic.
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Rowe JM, Welsh C, Pena RN, Wolf CR, Brown K, Whitelaw CBA. Illuminating role of CYP1A1 in skin function. J Invest Dermatol 2008; 128:1866-8. [PMID: 18185528 DOI: 10.1038/sj.jid.5701236] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Scippo ML, Eppe G, Saegerman C, Scholl G, De Pauw E, Maghuin-Rogister G, Focant JF. Chapter 14 Persistent Organochlorine Pollutants, Dioxins and Polychlorinated Biphenyls. FOOD CONTAMINANTS AND RESIDUE ANALYSIS 2008. [DOI: 10.1016/s0166-526x(08)00014-7] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
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Urban P, Pelclová D, Lukás E, Kupka K, Preiss J, Fenclová Z, Smerhovský Z. Neurological and neurophysiological examinations on workers with chronic poisoning by 2,3,7,8-TCDD: follow-up 35 years after exposure. Eur J Neurol 2006; 14:213-8. [PMID: 17250732 DOI: 10.1111/j.1468-1331.2006.01618.x] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Between 1965 and 1968, about 350 workers were accidentally exposed to 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) in a chemical plant, which was producing herbicides based on the trichlorophenoxyacetic acid. About 80 workers developed signs of poisoning. The estimated mean concentration of TCDD at the time of exposure was about 5000 pg/g of plasma fat. Only 15 subjects from the original cohort remained available for the recent follow-up in 2004. All were men, mean age 60 years. The mean current TCDD plasma concentration was 128 pg/g. Neurological examination revealed some CNS impairment in eight subjects. Signs of polyneuropathy were found in nine subjects, confirmed by NCV studies in three cases. Electroencephalography was abnormal in three cases; Visual-evoked potential in five cases. Acquired dyschromatopsia was detected in six patients. SPECT showed focal reduction of perfusion in various brain locations in all but one patient. Two neuropsychological variables and the frequency of abnormal neurophysiological tests in individual patients correlated with TCDD plasma level. The findings support the hypothesis that TCDD can damage the nervous system. In addition to a direct neurotoxic effect of TCDD, changes secondary to vasculopathy should be considered, in the pathophysiology of the damage, because of the high frequency of lipid metabolism disorders and their complications.
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Affiliation(s)
- P Urban
- Center for Occupational Health, National Institute of Public Health, Prague, Czech Republic.
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