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Park AS, Ritz B, Ling C, Cockburn M, Heck JE. Exposure to ambient dichloromethane in pregnancy and infancy from industrial sources and childhood cancers in California. Int J Hyg Environ Health 2017; 220:1133-1140. [PMID: 28720343 PMCID: PMC5572480 DOI: 10.1016/j.ijheh.2017.06.006] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2017] [Revised: 06/06/2017] [Accepted: 06/21/2017] [Indexed: 01/07/2023]
Abstract
BACKGROUND The incidence of childhood cancers has been increasing and environmental exposure to air toxics has been suggested as a possible risk factor. This study aims to explore ambient exposure to dichloromethane (methylene chloride). METHODS We frequency matched by birth year approximately 20 cancer-free controls identified from birth records to all childhood cancers ages 0-5 in the California Cancer Registry diagnosed from 1988 to 2012; i.e. 13,636 cases and a total of 270,673 controls. Information on industrial releases of dichloromethane within 3km of birth addresses was retrieved from mandatory industry reports to the EPA's Toxics Release Inventory (TRI). We derived exposure to dichloromethane within close vicinity of birth residences using several modeling techniques including unconditional logistic regression models with multiple buffer distances, inverse distance weighting, and quadratic decay models. RESULTS We observed elevated risks for germ cell tumors [Odds Ratio (OR): 1.52, 95% Confidence Interval (CI) 1.11, 2.08], particularly teratomas (OR: 2.08, 95% CI 1.38-3.13), and possible increased risk for acute myeloid leukemias (AML) (OR: 1.64, 95% CI 1.15-2.32 in the quadratic decay model). Risk estimates were similar in magnitude whether releases occurred in pregnancy or the child's first year of life. CONCLUSION Our findings suggest that exposure to industrial dichloromethane releases may be a risk factor for childhood germ cell tumors, teratomas, and possibly AML.
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Affiliation(s)
- Andrew S Park
- Department of Epidemiology, Fielding School of Public Health, University of California, 650 Charles E. Young Dr. S, Box 951772, Los Angeles, CA 90095-1772, USA
| | - Beate Ritz
- Department of Epidemiology, Fielding School of Public Health, University of California, 650 Charles E. Young Dr. S, Box 951772, Los Angeles, CA 90095-1772, USA
| | - Chenxiao Ling
- Department of Epidemiology, Fielding School of Public Health, University of California, 650 Charles E. Young Dr. S, Box 951772, Los Angeles, CA 90095-1772, USA
| | - Myles Cockburn
- Department of Preventive Medicine, Keck School of Medicine, University of Southern California, 2001 N. Soto Street, Suite 318-A, Los Angeles, CA, USA; Department of Epidemiology, Colorado School of Public Health, University of Colorado, 13001 East 17th Place, Aurora, CO 80045, USA; Cancer Prevention and Control Program, Colorado Comprehensive Cancer Center, University of Colorado, 13001 East 17th Place, Aurora, CO 80045, USA
| | - Julia E Heck
- Department of Epidemiology, Fielding School of Public Health, University of California, 650 Charles E. Young Dr. S, Box 951772, Los Angeles, CA 90095-1772, USA.
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Impaired Autophagosome Clearance Contributes to Local Anesthetic Bupivacaine-induced Myotoxicity in Mouse Myoblasts. Anesthesiology 2015; 122:595-605. [DOI: 10.1097/aln.0000000000000568] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Abstract
Background:
The current study examined the role(s) of autophagy in myotoxicity induced by bupivacaine in mouse myoblast C2c12 cells.
Methods:
C2c12 cells were treated with bupivacaine. Myotoxicity was evaluated by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay (n = 3 to 30), live/dead assay (n = 3 to 4), and morphological alterations (n = 3). Autophagosome formation was reflected by microtubule-associated protein light chain 3 conversion (n = 4 to 12) and light chain 3 punctation (n = 4 to 5). Autophagosome clearance was evaluated by p62 protein level (n = 4) and autolysosomes generation (n = 3).
Results:
Bupivacaine induced significant cell damage. Notably, there was a significant increase in autophagosome generation as evidenced by light chain 3 puncta formation (72.7 ± 6.9 vs. 2.1 ± 1.2) and light chain 3 conversion (2.16 ± 0.15 vs. 0.33 ± 0.04) in bupivacaine-treated cells. Bupivacaine inactivated the protein kinase B/mammalian target of rapamycin/p70 ribosomal protein S6 kinase signaling. However, cellular levels of p62 protein were significantly increased upon bupivacaine treatment (1.29 ± 0.15 vs. 1.00 ± 0.15), suggesting that the drug impaired autophagosome clearance. Further examination revealed that bupivacaine interrupted autophagosome–lysosome fusion (10.87% ± 1.48% vs. 32.94% ± 4.22%). Administration of rapamycin increased autophagosome clearance and, most importantly, improved the survival in bupivacaine-treated cells. However, knockdown of autophagy-related protein 5 (atg5) exacerbated bupivacaine-induced impairment of autophagosome clearance and myotoxicity.
Conclusions:
The data suggest that autophagosome formation was induced as a stress response mechanism after bupivacaine challenge; however, autophagosome clearance was impaired due to inadequate autophagosome–lysosome fusion. Therefore, impairment of autophagosome clearance appears to be a novel mechanism underlying bupivacaine-induced myotoxicity.
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Zeljezic D, Mladinic M, Kopjar N, Radulovic AH. Evaluation of genome damage in subjects occupationally exposed to possible carcinogens. Toxicol Ind Health 2015; 32:1570-80. [PMID: 25653038 DOI: 10.1177/0748233714568478] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
In occupational exposures, populations are simultaneously exposed to a mixture of chemicals. We aimed to evaluate DNA damage due to possible carcinogen exposure (phenylhydrazine, ethylene oxide, dichloromethane, and 1,2-dichloroethane) in lymphocytes of pharmaceutical industry workers from the same production line. Population comprised 16 subjects (9 females and 7 males) who were exposed to multiple chemicals for 8 months. Genome damage was assessed using alkaline comet assay, micronucleus assay, and comet assay coupled with fluorescent in situ hybridization (comet-FISH). After 8 months of exposure, the issue of irregular use of all available personal protective equipment (PPE) came into light. To decrease the risk of exposure, strict use of PPE was enforced. After 8 months of strict PPE use, micronuclei frequency and comet assay parameters in lymphocytes of pharmaceutical workers significantly decreased compared with prior period of irregular PPE use. Comet-FISH results indicated a significant shift in distribution of signals for the TP 53 gene toward a more frequent occurrence in the comet tail. Prolonged exposure to possible carcinogens may hinder DNA repair mechanisms and affect structural integrity of TP 53 Two indicators of loss of TP 53 gene integrity have risen, namely, TP 53 fragmentation rate in lymphocytes with persistently elevated primary damage and incidence of TP 53 deletions in undamaged lymphocytes.
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Affiliation(s)
- Davor Zeljezic
- Division for Mutagenesis, Institute for Medical Research and Occupational Health, Zagreb, Croatia
| | - Marin Mladinic
- Division for Mutagenesis, Institute for Medical Research and Occupational Health, Zagreb, Croatia
| | - Nevenka Kopjar
- Division for Mutagenesis, Institute for Medical Research and Occupational Health, Zagreb, Croatia
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Schlosser PM, Bale AS, Gibbons CF, Wilkins A, Cooper GS. Human health effects of dichloromethane: key findings and scientific issues. ENVIRONMENTAL HEALTH PERSPECTIVES 2015; 123:114-9. [PMID: 25325283 PMCID: PMC4314245 DOI: 10.1289/ehp.1308030] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/18/2013] [Accepted: 10/16/2014] [Indexed: 05/19/2023]
Abstract
BACKGROUND The U.S. EPA's Integrated Risk Information System (IRIS) completed an updated toxicological review of dichloromethane in November 2011. OBJECTIVES In this commentary we summarize key results and issues of this review, including exposure sources, identification of potential health effects, and updated physiologically based pharmacokinetic (PBPK) modeling. METHODS We performed a comprehensive review of primary research studies and evaluation of PBPK models. DISCUSSION Hepatotoxicity was observed in oral and inhalation exposure studies in several studies in animals; neurological effects were also identified as a potential area of concern. Dichloromethane was classified as likely to be carcinogenic in humans based primarily on evidence of carcinogenicity at two sites (liver and lung) in male and female B6C3F1 mice (inhalation exposure) and at one site (liver) in male B6C3F1 mice (drinking-water exposure). Recent epidemiologic studies of dichloromethane (seven studies of hematopoietic cancers published since 2000) provide additional data raising concerns about associations with non-Hodgkin lymphoma and multiple myeloma. Although there are gaps in the database for dichloromethane genotoxicity (i.e., DNA adduct formation and gene mutations in target tissues in vivo), the positive DNA damage assays correlated with tissue and/or species availability of functional glutathione S-transferase (GST) metabolic activity, the key activation pathway for dichloromethane-induced cancer. Innovations in the IRIS assessment include estimation of cancer risk specifically for a presumed sensitive genotype (GST-theta-1+/+), and PBPK modeling accounting for human physiological distributions based on the expected distribution for all individuals 6 months to 80 years of age. CONCLUSION The 2011 IRIS assessment of dichloromethane provides insights into the toxicity of a commonly used solvent.
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Affiliation(s)
- Paul M Schlosser
- National Center for Environmental Assessment, U.S. Environmental Protection Agency, Washington, DC, USA
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Wang F, Li C, Liu W, Jin Y. Oxidative damage and genotoxic effect in mice caused by sub-chronic exposure to low-dose volatile organic compounds. Inhal Toxicol 2013; 25:235-42. [DOI: 10.3109/08958378.2013.779767] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
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On enzyme-based anticancer molecular dietary manipulations. J Biomed Biotechnol 2012; 2012:790987. [PMID: 23049243 PMCID: PMC3461303 DOI: 10.1155/2012/790987] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2012] [Accepted: 08/03/2012] [Indexed: 01/01/2023] Open
Abstract
Evidence from both epidemiological and experimental observations has fuelled the belief that the high consumption of fruits and vegetables rich in nutrients and phytochemicals may help prevent cancer and heart disease in humans. This concept has been drastically simplified from the dietary approaches to the use of single bioactive components both as a single supplement or in functional foods to manipulate xenobiotic metabolism. These procedures, which aim to induce mutagen/carcinogen detoxification or inhibit their bioactivation, fail to take into account the multiple and paradoxical biological outcomes of enzyme modulators that make their effects unpredictable. Here, we show that the idea that the physiological roles of specific catalysts may be easily manipulated by regular long-term administration of isolated nutrients and other chemicals derived from food plants is not viable. In contrast, we claim that the consumption of healthy diets is most likely to reduce mutagenesis and cancer risk, and that both research endeavours and dietary recommendations should be redirected away from single molecules to dietary patterns as a main strategy for public health policy.
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Susceptibility to the cytogenetic effects of dichloromethane is related to the glutathione S-transferase theta phenotype. Toxicol Lett 2010; 199:218-24. [DOI: 10.1016/j.toxlet.2010.09.002] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2010] [Revised: 09/01/2010] [Accepted: 09/02/2010] [Indexed: 11/22/2022]
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Rossi AM, Hansteen IL, Skjelbred CF, Ballardin M, Maggini V, Murgia E, Tomei A, Viarengo P, Knudsen LE, Barale R, Norppa H, Bonassi S. Association between frequency of chromosomal aberrations and cancer risk is not influenced by genetic polymorphisms in GSTM1 and GSTT1. ENVIRONMENTAL HEALTH PERSPECTIVES 2009; 117:203-8. [PMID: 19270789 PMCID: PMC2649221 DOI: 10.1289/ehp.11769] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/06/2008] [Accepted: 09/16/2008] [Indexed: 05/27/2023]
Abstract
BACKGROUND The frequency of chromosomal aberrations (CA) in peripheral blood lymphocytes of healthy individuals has been associated with cancer risk. It is presently unclear whether this association is influenced by individual susceptibility factors such as genetic polymorphisms of xenobiotic-metabolizing enzymes. OBJECTIVES To evaluate the role of polymorphisms in glutathione S-transferase (GST) M1 (GSTM1) and theta 1 (GSTT1) as effect modifiers of the association between CA and cancer risk. METHODS A case-control study was performed pooling data from cytogenetic studies carried out in 1974-1995 in three laboratories in Italy, Norway, and Denmark. A total of 107 cancer cases were retrieved from national registries and matched to 291 controls. The subjects were classified as low, medium, and high by tertile of CA frequency. The data were analyzed by setting up a Bayesian model that included prior information about cancer risk by CA frequency. RESULTS The association between CA frequency and cancer risk was confirmed [OR(medium) (odds ratio)(medium) = 1.5, 95% credibility interval (CrI), 0.9-2.5; OR(high) = 2.8, 95% CrI, 1.6-4.6], whereas no effect of the genetic polymorphism was observed. A much stronger association was seen in the Italian subset (OR(high)= 9.4, 95% CrI, 2.6-28.0), which was characterized by a lower technical variability of the cytogenetic analysis. CA level was particularly associated with cancer of the respiratory tract (OR(high)= 6.2, 95% CrI, 1.5-20.0), the genitourinary tract (OR(high) = 4.0, 95% CrI, 1.4-10.0), and the digestive tract (OR(high) = 2.8, 95% CrI, 1.2-5.8). CONCLUSIONS Despite the small size of the study groups, our results substantiate the cancer risk predictivity of CA frequency, ruling against a strong modifying effect of GSTM1 and GSTT1 polymorphisms.
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Affiliation(s)
| | - Inger-Lise Hansteen
- Department of Laboratory Medicine, Section of Medical Genetics, Telemark Hospital, Skien, Norway
| | - Camilla Furu Skjelbred
- Department of Laboratory Medicine, Section of Medical Genetics, Telemark Hospital, Skien, Norway
| | | | | | - Elena Murgia
- Department of Biology, Pisa University, Pisa, Italy
| | | | - Paolo Viarengo
- Department of Aerospace Engineering, University of Naples Federico II, Naples, Italy
| | - Lisbeth E. Knudsen
- Environmental Health, Institute of Public Health, University of Copenhagen, Copenhagen, Denmark
| | | | - Hannu Norppa
- New Technologies and Risks, Work Environment Development, Finnish Institute of Occupational Health, Helsinki, Finland
| | - Stefano Bonassi
- Unit of Molecular Epidemiology, National Cancer Research Institute, Genoa, Italy
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Speit G, Fröhler-Keller M, Schütz P, Neuss S. Low sensitivity of the comet assay to detect acetaldehyde-induced genotoxicity. MUTATION RESEARCH-GENETIC TOXICOLOGY AND ENVIRONMENTAL MUTAGENESIS 2008; 657:93-7. [DOI: 10.1016/j.mrgentox.2008.07.010] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/13/2008] [Revised: 07/29/2008] [Accepted: 07/30/2008] [Indexed: 11/27/2022]
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Speit G, Schmid O, Neuss S, Schütz P. Genotoxic effects of formaldehyde in the human lung cell line A549 and in primary human nasal epithelial cells. ENVIRONMENTAL AND MOLECULAR MUTAGENESIS 2008; 49:300-307. [PMID: 18366098 DOI: 10.1002/em.20386] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
The alkaline comet assay was used to further characterize the induction of DNA-protein crosslinks (DPX) by formaldehyde (FA) and their removal in the human lung cell line A549 and in primary human nasal epithelial cells (HNEC). DPX were indirectly measured as the reduction of gamma ray-induced DNA migration. FA induced DPX in A549 cells in a concentration-related manner in the range of 100-300 microM. This result is in agreement with previous studies using different mammalian cell lines. The main new findings of the present study are: (i) Determination of cytotoxicity in relation to genotoxicity strongly depend on the method used. Cytotoxicity measured as the reduction in cell counts 48 hr after addition of FA to the cultures occurred parallel to the induction of DPX while colony forming ability was already reduced at 10 times lower FA concentrations; (ii) DPX induced by a 1-hr FA treatment were completely removed within 8 hr cultivation in fresh medium while in the presence of FA in the medium DPX levels remained unchanged for 24 hr; (iii) Induction and removal of DPX did not fundamentally differ between exponentially growing and confluent A549 cultures; (iv) Slowly proliferating HNEC showed the same sensitivity towards FA-induced DPX as A549 cells (i.e. the same FA concentrations induced DPX under the same experimental conditions) and removed DPX with a similar efficiency. In summary, these results contribute to a better understanding of the genotoxic activity of FA in vitro and indicate that the tested cultured primary and permanent human cells do not differ fundamentally with regard to the processing of FA-induced primary genotoxic effects.
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Affiliation(s)
- Günter Speit
- Institut für Humangenetik, Universität Ulm, Ulm, Germany.
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Speit G, Neuss S, Schütz P, Fröhler-Keller M, Schmid O. The genotoxic potential of glutaraldehyde in mammalian cells in vitro in comparison with formaldehyde. MUTATION RESEARCH-GENETIC TOXICOLOGY AND ENVIRONMENTAL MUTAGENESIS 2008; 649:146-54. [DOI: 10.1016/j.mrgentox.2007.08.010] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/18/2007] [Revised: 08/06/2007] [Accepted: 08/20/2007] [Indexed: 11/30/2022]
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