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Dellarco M, Zaleski R, Gaborek BJ, Qian H, Bellin CA, Egeghy P, Heard N, Jolliet O, Lander DR, Sunger N, Stylianou KS, Tanir JY. Using exposure bands for rapid decision making in the RISK21 tiered exposure assessment. Crit Rev Toxicol 2017; 47:317-341. [PMID: 28266262 PMCID: PMC6091571 DOI: 10.1080/10408444.2016.1270255] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
The ILSI Health and Environmental Sciences Institute (HESI) Risk Assessment in the Twenty-first Century (RISK21) project was initiated to address and catalyze improvements in human health risk assessment. RISK21 is a problem formulation-based conceptual roadmap and risk matrix visualization tool, facilitating transparent evaluation of both hazard and exposure components. The RISK21 roadmap is exposure-driven, that is, exposure is used as the second step (after problem formulation) to define and focus the assessment. This paper describes the exposure tiers of the RISK21 matrix and the approaches to adapt readily available information to more quickly inform exposure at a screening level. In particular, exposure look-up tables were developed from available exposure tools (European Centre for Ecotoxicology and Toxicology of Chemicals (ECETOC) Targeted Risk Assessment (TRA) for worker exposure, ECETOC TRA, European Solvents Industry Group (ESIG) Generic Exposure Scenario (GES) Risk and Exposure Tool (EGRET) for consumer exposure, and USEtox® for indirect exposure to humans via the environment) and were tested in a hypothetical mosquito bed netting case study. A detailed WHO risk assessment for a similar mosquito net use served as a benchmark for the performance of the RISK21 approach. The case study demonstrated that the screening methodologies provided suitable conservative exposure estimates for risk assessment. The results of this effort showed that the RISK21 approach is useful for defining future assessment efforts, focusing assessment activities and visualizing results.
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Affiliation(s)
- M Dellarco
- a National Children?s Study, Eunice Kennedy Shriver National Institute of Child Health and Human Development , Bethesda , MD , USA
| | - R Zaleski
- b Occupational and Public Health Division, ExxonMobil Biomedical Sciences, Inc , Annandale , NJ , USA
| | - B J Gaborek
- c DuPont Haskell Global Centers for Health and Environmental Sciences, DuPont , Newark , DE , USA
| | - H Qian
- b Occupational and Public Health Division, ExxonMobil Biomedical Sciences, Inc , Annandale , NJ , USA
| | - C A Bellin
- c DuPont Haskell Global Centers for Health and Environmental Sciences, DuPont , Newark , DE , USA
| | - P Egeghy
- d National Exposure Research Laboratory , U.S. Environmental Protection Agency, Research Triangle Park , NC , USA
| | - N Heard
- e Product Safety, Operator and Consumer Safety, Syngenta Crop Protection LLC , Greensboro , NC , USA
| | - O Jolliet
- f Department of Environmental Health Sciences , University of Michigan , Ann Arbor , MI , USA
| | - D R Lander
- c DuPont Haskell Global Centers for Health and Environmental Sciences, DuPont , Newark , DE , USA
| | - N Sunger
- g Toxicology and Environmental Research & Consulting, The Dow Chemical Company , Midland , MI , USA
| | - K S Stylianou
- f Department of Environmental Health Sciences , University of Michigan , Ann Arbor , MI , USA
| | - J Y Tanir
- h ILSI Health and Environmental Sciences Institute , Washington , DC , USA
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Lorge E, Moore MM, Clements J, O'Donovan M, Fellows MD, Honma M, Kohara A, Galloway S, Armstrong MJ, Thybaud V, Gollapudi B, Aardema MJ, Tanir JY. Standardized cell sources and recommendations for good cell culture practices in genotoxicity testing. Mutat Res Genet Toxicol Environ Mutagen 2016; 809:1-15. [PMID: 27692294 DOI: 10.1016/j.mrgentox.2016.08.001] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/29/2016] [Revised: 07/29/2016] [Accepted: 08/02/2016] [Indexed: 11/16/2022]
Abstract
Good cell culture practice and characterization of the cell lines used are of critical importance in in vitro genotoxicity testing. The objective of this initiative was to make continuously available stocks of the characterized isolates of the most frequently used mammalian cell lines in genotoxicity testing anywhere in the world ('IVGT' cell lines). This project was organized under the auspices of the International Life Sciences Institute (ILSI) Health and Environmental Sciences Institute (HESI) Project Committee on the Relevance and Follow-up of Positive Results in In Vitro Genetic Toxicity (IVGT) Testing. First, cell isolates were identified that are as close as possible to the isolate described in the initial publications reporting their use in genotoxicity testing. The depositors of these cell lines managed their characterization and their expansion for preparing continuously available stocks of these cells that are stored at the European Collection of Cell Cultures (ECACC, UK) and the Japanese Collection of Research Bioresources (JCRB, Japan). This publication describes how the four 'IVGT' cell lines, i.e. L5178Y TK+/- 3.7.2C, TK6, CHO-WBL and CHL/IU, were prepared for deposit at the ECACC and JCRB cell banks. Recommendations for handling these cell lines and monitoring their characteristics are also described. The growth characteristics of these cell lines (growth rates and cell cycles), their identity (karyotypes and genetic status) and ranges of background frequencies of select endpoints are also reported to help in the routine practice of genotoxicity testing using these cell lines.
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Affiliation(s)
- E Lorge
- Servier Group, 45520, Gidy, France
| | - M M Moore
- Ramboll Environ, Little Rock, AR, 72201, USA
| | - J Clements
- Covance Laboratories Ltd, Harrogate, HG3 1PY, UK
| | - M O'Donovan
- O'Donovan GT Consulting Ltd., Epperstone, Nottingham, NG14 6AG, UK
| | - M D Fellows
- AstraZeneca, Drug Safety and Metabolism, Cambridge, CB4 0WG, UK
| | - M Honma
- National Institute of Health Sciences, Tokyo, Japan
| | - A Kohara
- JCRB Cell Bank, National Institutes of Biomedical Innovation, Health and Nutrition, Osaka, Japan
| | - S Galloway
- Merck Research Laboratories, W 45-316, West Point, PA 19486, USA
| | - M J Armstrong
- Merck Research Laboratories, W 45-316, West Point, PA 19486, USA
| | - V Thybaud
- Sanofi, 94400, Vitry sur Seine, France
| | - B Gollapudi
- Exponent, Inc., 1910 St. Andrews St., Midland, MI 48640, USA
| | - M J Aardema
- Marilyn Aardema Consulting LLC, Fairfield, OH 45014, USA
| | - J Y Tanir
- ILSI Health and Environmental Sciences Institute, Washington, DC 20005, USA.
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Johnson GE, Soeteman-Hernández LG, Gollapudi BB, Bodger OG, Dearfield KL, Heflich RH, Hixon JG, Lovell DP, MacGregor JT, Pottenger LH, Thompson CM, Abraham L, Thybaud V, Tanir JY, Zeiger E, van Benthem J, White PA. Derivation of point of departure (PoD) estimates in genetic toxicology studies and their potential applications in risk assessment. Environ Mol Mutagen 2014; 55:609-23. [PMID: 24801602 PMCID: PMC6710644 DOI: 10.1002/em.21870] [Citation(s) in RCA: 114] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/28/2014] [Revised: 04/07/2014] [Accepted: 04/11/2014] [Indexed: 05/13/2023]
Abstract
Genetic toxicology data have traditionally been employed for qualitative, rather than quantitative evaluations of hazard. As a continuation of our earlier report that analyzed ethyl methanesulfonate (EMS) and methyl methanesulfonate (MMS) dose-response data (Gollapudi et al., 2013), here we present analyses of 1-ethyl-1-nitrosourea (ENU) and 1-methyl-1-nitrosourea (MNU) dose-response data and additional approaches for the determination of genetic toxicity point-of-departure (PoD) metrics. We previously described methods to determine the no-observed-genotoxic-effect-level (NOGEL), the breakpoint-dose (BPD; previously named Td), and the benchmark dose (BMD10 ) for genetic toxicity endpoints. In this study we employed those methods, along with a new approach, to determine the non-linear slope-transition-dose (STD), and alternative methods to determine the BPD and BMD, for the analyses of nine ENU and 22 MNU datasets across a range of in vitro and in vivo endpoints. The NOGEL, BMDL10 and BMDL1SD PoD metrics could be readily calculated for most gene mutation and chromosomal damage studies; however, BPDs and STDs could not always be derived due to data limitations and constraints of the underlying statistical methods. The BMDL10 values were often lower than the other PoDs, and the distribution of BMDL10 values produced the lowest median PoD. Our observations indicate that, among the methods investigated in this study, the BMD approach is the preferred PoD for quantitatively describing genetic toxicology data. Once genetic toxicology PoDs are calculated via this approach, they can be used to derive reference doses and margin of exposure values that may be useful for evaluating human risk and regulatory decision making.
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Affiliation(s)
- G E Johnson
- Institute of Life Science, College of Medicine, Swansea University, Swansea, Wales, United Kingdom
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