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Kappenberg F, Duda JC, Schürmeyer L, Gül O, Brecklinghaus T, Hengstler JG, Schorning K, Rahnenführer J. Guidance for statistical design and analysis of toxicological dose-response experiments, based on a comprehensive literature review. Arch Toxicol 2023; 97:2741-2761. [PMID: 37572131 PMCID: PMC10474994 DOI: 10.1007/s00204-023-03561-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2023] [Accepted: 07/13/2023] [Indexed: 08/14/2023]
Abstract
The analysis of dose-response, concentration-response, and time-response relationships is a central component of toxicological research. A major decision with respect to the statistical analysis is whether to consider only the actually measured concentrations or to assume an underlying (parametric) model that allows extrapolation. Recent research suggests the application of modelling approaches for various types of toxicological assays. However, there is a discrepancy between the state of the art in statistical methodological research and published analyses in the toxicological literature. The extent of this gap is quantified in this work using an extensive literature review that considered all dose-response analyses published in three major toxicological journals in 2021. The aspects of the review include biological considerations (type of assay and of exposure), statistical design considerations (number of measured conditions, design, and sample sizes), and statistical analysis considerations (display, analysis goal, statistical testing or modelling method, and alert concentration). Based on the results of this review and the critical assessment of three selected issues in the context of statistical research, concrete guidance for planning, execution, and analysis of dose-response studies from a statistical viewpoint is proposed.
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Affiliation(s)
- Franziska Kappenberg
- Department of Statistics, TU Dortmund University, Vogelpothsweg 87, 44227, Dortmund, Germany.
| | - Julia C Duda
- Department of Statistics, TU Dortmund University, Vogelpothsweg 87, 44227, Dortmund, Germany
| | - Leonie Schürmeyer
- Department of Statistics, TU Dortmund University, Vogelpothsweg 87, 44227, Dortmund, Germany
| | - Onur Gül
- Department of Statistics, TU Dortmund University, Vogelpothsweg 87, 44227, Dortmund, Germany
| | - Tim Brecklinghaus
- Leibniz Research Centre for Working Environment and Human Factors at the Technical University of Dortmund (IfADo), Ardeystrasse 67, 44139, Dortmund, Germany
| | - Jan G Hengstler
- Leibniz Research Centre for Working Environment and Human Factors at the Technical University of Dortmund (IfADo), Ardeystrasse 67, 44139, Dortmund, Germany
| | - Kirsten Schorning
- Department of Statistics, TU Dortmund University, Vogelpothsweg 87, 44227, Dortmund, Germany
| | - Jörg Rahnenführer
- Department of Statistics, TU Dortmund University, Vogelpothsweg 87, 44227, Dortmund, Germany
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2
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Möllenhoff K, Schorning K, Kappenberg F. Identifying alert concentrations using a model-based bootstrap approach. Biometrics 2023; 79:2076-2088. [PMID: 36385693 DOI: 10.1111/biom.13799] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2022] [Accepted: 10/31/2022] [Indexed: 11/18/2022]
Abstract
The determination of alert concentrations, where a pre-specified threshold of the response variable is exceeded, is an important goal of concentration-response studies. The traditional approach is based on investigating the measured concentrations and attaining statistical significance of the alert concentration by using a multiple t-test procedure. In this paper, we propose a new model-based method to identify alert concentrations, based on fitting a concentration-response curve and constructing a simultaneous confidence band for the difference of the response of a concentration compared to the control. In order to obtain these confidence bands, we use a bootstrap approach which can be applied to any functional form of the concentration-response curve. This particularly offers the possibility to investigate also those situations where the concentration-response relationship is not monotone and, moreover, to detect alerts at concentrations which were not measured during the study, providing a highly flexible framework for the problem at hand.
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3
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Wright PSR, Smith GF, Briggs KA, Thomas R, Maglennon G, Mikulskis P, Chapman M, Greene N, Phillips BU, Bender A. Retrospective analysis of the potential use of virtual control groups in preclinical toxicity assessment using the eTOX database. Regul Toxicol Pharmacol 2023; 138:105309. [PMID: 36481280 DOI: 10.1016/j.yrtph.2022.105309] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2022] [Revised: 11/17/2022] [Accepted: 11/25/2022] [Indexed: 12/12/2022]
Abstract
Virtual Control Groups (VCGs) based on Historical Control Data (HCD) in preclinical toxicity testing have the potential to reduce animal usage. As a case study we retrospectively analyzed the impact of replacing Concurrent Control Groups (CCGs) with VCGs on the treatment-relatedness of 28 selected histopathological findings reported in either rat or dog in the eTOX database. We developed a novel methodology whereby statistical predictions of treatment-relatedness using either CCGs or VCGs of varying covariate similarity to CCGs were compared to designations from original toxicologist reports; and changes in agreement were used to quantify changes in study outcomes. Generally, the best agreement was achieved when CCGs were replaced with VCGs with the highest level of similarity; the same species, strain, sex, administration route, and vehicle. For example, balanced accuracies for rat findings were 0.704 (predictions based on CCGs) vs. 0.702 (predictions based on VCGs). Moreover, we identified covariates which resulted in poorer identification of treatment-relatedness. This was related to an increasing incidence rate divergence in HCD relative to CCGs. Future databases which collect data at the individual animal level including study details such as animal age and testing facility are required to build adequate VCGs to accurately identify treatment-related effects.
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Affiliation(s)
| | - Graham F Smith
- AstraZeneca, Data Science and AI, Clinical Pharmacology and Safety Sciences, R&D, Cambridge, United Kingdom
| | | | | | - Gareth Maglennon
- AstraZeneca, Oncology Pathology, Clinical Pharmacology and Safety Sciences, R&D, Melbourn, United Kingdom
| | - Paulius Mikulskis
- AstraZeneca, Imaging and Data Analytics, Clinical Pharmacology & Safety Sciences, R&D, Gothenburg, Sweden
| | - Melissa Chapman
- AstraZeneca, Toxicology, Clinical Pharmacology and Safety Sciences, R&D, Melbourn, United Kingdom
| | - Nigel Greene
- AstraZeneca, Imaging and Data Analytics, Clinical Pharmacology & Safety Sciences, R&D, Waltham, MA, USA
| | - Benjamin U Phillips
- AstraZeneca, Data Sciences and Quantitative Biology, Discovery Sciences, Cambridge Biomedical Campus, Cambridge, United Kingdom
| | - Andreas Bender
- University of Cambridge, Chemistry, Cambridge, United Kingdom.
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4
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Marks CA, Allen L, Lindeberg H. Non-Lethal Dose-Response Models Replace Lethal Bioassays for Predicting the Hazard of Para-Aminopropiophenone to Australian Wildlife. Animals (Basel) 2023; 13:ani13030472. [PMID: 36766361 PMCID: PMC9913665 DOI: 10.3390/ani13030472] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2022] [Revised: 01/23/2023] [Accepted: 01/23/2023] [Indexed: 02/01/2023] Open
Abstract
Para-aminopropiophenone (PAPP) is a potent methaemoglobin (MetHb) forming agent used for the lethal control of exotic carnivores and mustelids. To assess the sensitivity of Australian wildlife to PAPP we developed an in vivo assay that did not use death as an endpoint. Sub-lethal dose-response data were modelled to predict PAPP doses required to achieve an endpoint set at 80% MetHb (MetHb80). The comparative sensitivity of non-target mammals referenced to this endpoint was found to be highly variable, with southern brown bandicoots (Isoodon obesulus) the most sensitive species (MetHb80 = 6.3 mg kg-1) and bush rats (Rattus fuscipes) the most tolerant (MetHb80 = 1035 mg kg-1). Published LD50 estimates were highly correlated with PAPP doses modelled to achieve the MetHb80 endpoint (r2 = 0.99, p < 0.001). Most dose-response data for native mammals were collected in the field or in semi-natural enclosures, permitting PAPP and placebo dosed animals to be fitted with tracking transmitters and transponders and released at their point of capture. A protracted morbidity and mortality was observed only in Australian ravens (Corvus coronoides). The combination of sub-lethal dose-response assay and survival data collected in the field provided more relevant information about the actual hazard of pest control agents to non-target wildlife species than laboratory-based lethal-dose bioassays. We discuss the need to replace lethal-dose data with biologically meaningful insights able to define a continuum of toxicological hazards that better serve the needs of conservation and veterinary scientists and wildlife managers.
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Affiliation(s)
- Clive A. Marks
- Nocturnal Wildlife Research Pty Ltd., P.O. Box 2126, Melbourne, VIC 3145, Australia
- Manaaki Whenua Landcare Research, Lincoln P.O. Box 69040, New Zealand
- Correspondence:
| | - Lee Allen
- Queensland Department of Agriculture Fisheries and Forestry, Toowoomba, QLD 4350, Australia
| | - Heli Lindeberg
- Natural Resources Institute Finland (Luke), Production Systems, Halolantie 31 A, FI-71750 Maaninka, Finland
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5
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Toxicity studies of select ionic liquids (1-ethyl-3-methylimidazolium chloride, 1-butyl-3-methylimidazolium chloride, 1-butyl-1-methylpyrrolidinium chloride, and n-butylpyridinium chloride) administered in drinking water to Sprague Dawley (Hsd:Sprague Dawley SD) rats and B6C3F1/N mice. TOXICITY REPORT SERIES 2022:NTP-TOX-103. [PMID: 35652689 PMCID: PMC9638888 DOI: 10.22427/ntp-tox-103] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Ionic liquids (ILs) are synthetic solvents with applications in a variety of industrial and chemical industries. Human exposure to this diverse chemical class is primarily through dermal or oral routes. Research suggests toxicity may be associated with IL structural characteristics, including the type of cation base or alkyl chain substitutions associated with the cation. To further investigate this hypothesis, the National Toxicology Program (NTP) conducted 3-month toxicity studies in male and female Sprague Dawley (Hsd:Sprague Dawley SD) rats and B6C3F1/N mice (n = 10/sex/exposure group; 3 exposure concentrations per IL) to compare the relative toxicities of four ILs administered via drinking water-1-ethyl-3-methylimidazolium chloride (Emim-Cl), 1-butyl-3-methylimidazolium chloride (Bmim-Cl), 1-butyl-1-methylpyrrolidinium chloride (Bmpy-Cl), and n-butylpyridinium chloride (NBuPy-Cl). (Abstract Abridged).
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6
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Jensen SM, Kluxen FM, Ritz C. Benchmark dose modelling in regulatory ecotoxicology, a potential tool in pest management. PEST MANAGEMENT SCIENCE 2022; 78:1772-1779. [PMID: 34908226 DOI: 10.1002/ps.6759] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/19/2021] [Revised: 12/01/2021] [Accepted: 12/15/2021] [Indexed: 06/14/2023]
Abstract
For several authorities, benchmark dose (BMD) methodology has become the recommended approach by which to derive reference values for risk assessment. However, in practice, the BMD approach is not standard use in risk assessment for pesticides where the no observed adverse effect level, lowest observed adverse effect level and effective dose (ED50 or EDx ) prevail. Regression-based BMD and the benchmark dose lower confidence limit (BMDL) have several advantages, such as utilizing more information from the generated data and being less dependent on tested dose levels. However, the BMD approach requires some degree of expert knowledge for defining an appropriate risk level for estimating the BMD and using more sophisticated statistical methods to calculate BMD and BMDL. The BMD approach is one way to move away from p value-based binary decision-making towards putting the weight on effect sizes. We review the advantages and disadvantages of focusing on the BMD approach for risk assessment of pesticides. Further, we discuss potential applications in efficacy trials for pest management purposes. © 2021 Society of Chemical Industry.
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Affiliation(s)
- Signe M Jensen
- Department of Plant and Environmental Sciences, University of Copenhagen, Taastrup, Denmark
| | | | - Christian Ritz
- National Institute of Public Health, University of Southern Denmark, Odense, Denmark
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7
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Kale VP, Bebenek I, Ghantous H, Kapeghian J, Singh BP, Thomas LJ. Practical Considerations in Determining Adversity and the No-Observed-Adverse-Effect-Level (NOAEL) in Nonclinical Safety Studies: Challenges, Perspectives and Case Studies. Int J Toxicol 2022; 41:143-162. [PMID: 35230174 DOI: 10.1177/10915818211073047] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Determining the adverse nature of findings from nonclinical safety studies often poses a challenge for the key stakeholders responsible for interpreting the results of definitive toxicity studies in support of pharmaceutical product development. Although there are instances in which responses to treatment clearly indicate intolerability or tissue injury associated with dysfunction; in practice, more often there is uncertainty in characterizing an effect of drug treatment as adverse or not. This is due to the inherent variability in responses of biological test systems to toxicological insults, leaving the ultimate analyses of adversity to individual interpretation and subjectivity. This article is a follow-up to the workshop entitled, "Adverse or Not Adverse?: Thinking process behind adversity determination during nonclinical drug development," conducted at the 58th Annual Meeting of the Society of Toxicology, March 2019 in Baltimore, MD. In this paper, we further discuss and incorporate the perspectives of authors representing different roles, such as Study Director, Study Pathologist, Pharmacology/Toxicology Reviewer (U.S. Food and Drug Administration), and Sponsor in the determination and use of adversity. We also present a practical stepwise approach as an aid in this assessment, and further apply these principles to discuss 10 case studies with different therapeutic modalities and unique challenges.
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Affiliation(s)
| | - Ilona Bebenek
- Food and Drug Administration, Silver Spring, MD, USA
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8
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Altan S, Amaratunga D, Cabrera J, Garren J, Geys H, Kolassa J, LeBlond D, Li D, Liao J, Liu J, Lubomirski M, Miro-Quesada G, Novick S, Otava M, Peterson J, Reckermann K, Schofield T, Tan C, Tatikola K, Tekle F, Thomas J, Vukovinsky K. Survey and Recommendations on the Use of P-Values Driving Decisions in Nonclinical Pharmaceutical Applications. Stat Biopharm Res 2022. [DOI: 10.1080/19466315.2022.2038258] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Affiliation(s)
| | | | | | | | | | | | | | | | | | - Jia Liu
- Pfizer Inc, Andover, Ma, 01810
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9
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Utembe W, Tlotleng N, Kamng'ona AW. A systematic review on the effects of nanomaterials on gut microbiota. CURRENT RESEARCH IN MICROBIAL SCIENCES 2022; 3:100118. [PMID: 35909630 PMCID: PMC9325792 DOI: 10.1016/j.crmicr.2022.100118] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Nanomaterials have been shown to affect gut microbiota (GM) both in vivo and in vitro. The effects have been shown to depend on size, dose, dose duration and functional groups. In general, more studies seem to indicate dose-dependent adverse effects of NMs towards GM. Standardized protocols are needed for characterization of NMs, dosing, and test systems (both in vitro and in vivo).
Some nanomaterials (NMs) have been shown to possess antimicrobial activity and cause GM dysbiosis. Since NMs are being used widely, a systematic assessment of the effects of NMs on GM is warranted. In this systematic review, a total of 46 in vivo and 22 in vitro studies were retrieved from databases and search engines including Science-Direct, Pubmed and Google scholar. Criteria for assessment of studies included use of in vitro or in vivo studies, characterization of NMs, use of single or multiple doses as well as consistency of results. GM dysbiosis has been studied most widely on TiO2, Ag, Zn-based NMs. There was moderate evidence for GM dysbiosis caused by Zn- and Cu-based NMs, Cu-loaded chitosan NPs and Ag NMs, and anatase TiO2 NPs, as well as low evidence for SWCNTs, nanocellulose, SiO2, Se, nanoplastics, CeO2, MoO3 and graphene-based NMs. Most studies indicate adverse effects of NMs towards GM. However, more work is required to elucidate the differences on the reported effects of NM by type and sex of organisms, size, shape and surface properties of NMs as well as effects of exposure to mixtures of NMs. For consistency and better agreement among studies on GM dysbiosis, there is need for internationally agreed protocols on, inter alia, characterization of NMs, dosing (amounts, frequency and duration), use of sonication, test systems (both in vitro and in vivo), including oxygen levels for in vitro models.
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10
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Kluxen FM, Weber K, Strupp C, Jensen SM, Hothorn LA, Garcin JC, Hofmann T. Using historical control data in bioassays for regulatory toxicology. Regul Toxicol Pharmacol 2021; 125:105024. [PMID: 34364928 DOI: 10.1016/j.yrtph.2021.105024] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2021] [Revised: 06/21/2021] [Accepted: 07/30/2021] [Indexed: 12/12/2022]
Abstract
Historical control data (HCD) consist of pooled control group responses from bioassays. These data must be collected and are often used or reported in regulatory toxicology studies for multiple purposes: as quality assurance for the test system, to help identify toxicological effects and their effect-size relevance and to address the statistical multiple comparison problem. The current manuscript reviews the various classical and potential new approaches for using HCD. Issues in current practice are identified and recommendations for improved use and discussion are provided. Furthermore, stakeholders are invited to discuss whether it is necessary to consider uncertainty when using HCD formally and statistically in toxicological discussions and whether binary inclusion/exclusion criteria for HCD should be revised to a tiered information contribution to assessments. Overall, the critical value of HCD in toxicological bioassays is highlighted when used in a weight-of-evidence assessment.
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Affiliation(s)
| | | | | | - Signe M Jensen
- Department of Plant and Efoldnvironmental Sciences, University of Copenhagen, Copenhagen, Denmark
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11
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Bobadilla Alvarez MC, Palomino Cadenas EJ. CONTROL DE Aedes aegypti (DIPTERA: CULICIDAE) MEDIANTE ACTINOBACTERIAS FORMADORAS DE BIOPELÍCULAS. ACTA BIOLÓGICA COLOMBIANA 2021. [DOI: 10.15446/abc.v26n3.86966] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
El phylum Actinobacteria incluye miembros productores de compuestos bioinsecticidas. No obstante, la sobreexplotacion de metabolitos derivados de Streptomyces ha conllevado a explorar nuevas moléculas provenientes de bacterias no estreptomicetos para contrarrestar la resistencia a insecticidas químicos en Aedes aegypti. Concordantes con el uso de bioagentes ecológicos, esta investigación caracterizó actinobacterias formadoras de biopelículas con el fin de evaluar su dinámica de crecimiento, actividad larvicida y efectos subletales. La identificación, crecimiento de biopelículas y bioactividades se realizaron por cultivos, análisis de imágenes por fotomicrografía y bioensayos. Los resultados mostraron que las biopelículas pertenecen a Pseudonocardiaceae (PsA1TA) y Corynebacteriaceae (CoA2CA) característicamente dependientes del revestimiento cuticular. PsA1TA coloniza estructuras membranosas de tórax y abdomen con microcolonias aleatoriamente distribuidas que desarrollan a extensas biopelículas mono y biestratificadas, al cubrir cuatro veces la amplitud toracoabdominal (envergadura infectiva entre 1010 µm a 1036 µm). En contraste, CoA2CA envuelve radialmente estructuras esclerotizadas cefálica y anal al triplicar la amplitud de tales órganos (1820 a 2030 µm y 1650 a 1860 µm, respectivamente). Las biopelículas ejercieron mortalidad diferenciada a todos los estadios larvales, no obstante, PsA1TA resultó más mortal y virulento en el segundo estadio larval (58 %-96 horas, TL50: 3,4 días), mientras que CoA2CA lo fue en el cuarto estadio larval (85 %-96 horas, TL50: 2,5 días). CoA2CA indujo emergencia incompleta de adultos farados y despliegue de tarsos curvos en emergentes, además de revestir con robustas biopelículas cadáveres larvarios. Las biopelículas actinobacterianas revelaron ejercer función larvicida y respuestas subletales en A. aegypti.
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12
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Huang MC, Furr JR, Robinson VG, Betz L, Shockley K, Cunny H, Witt K, Waidyanatha S, Germolec D. Oral deoxynivalenol toxicity in Harlan Sprague Dawley (Hsd:Sprague Dawley® SD®) rat dams and their offspring. Food Chem Toxicol 2021; 148:111963. [PMID: 33388407 PMCID: PMC7923685 DOI: 10.1016/j.fct.2020.111963] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2020] [Revised: 12/15/2020] [Accepted: 12/28/2020] [Indexed: 10/22/2022]
Abstract
There is widespread human exposure to deoxynivalenol (DON), a fungal mycotoxin found globally in many grain-based foods and animal feed. Acute exposures to high levels of DON are associated with gastrointestinal effects and emesis in humans and some animals, but the effects of low-dose exposures throughout the lifetime, a more likely exposure scenario in humans, are understudied. Therefore, this study was designed to identify doses of DON that could be used to evaluate long-term toxicity following perinatal exposure. Time-mated Harlan Sprague Dawley (Hsd:Sprague Dawley® SD®) rats were administered 0, 0.03, 0.1, 0.3, 1, or 3 mg/kg/day of DON once daily via gavage starting on gestational day 6 through postnatal day (PND) 27. F1 animals were administered the same dose as their respective dams via gavage starting on PND 12 until PND 27. Animals were euthanized on PND 28. DON had no effect on maternal body weight or feed consumption at any dose. Findings were limited to the 3 mg/kg/day group: F0 females had smaller live litter sizes than controls and F1 pups had lower body weight (4-13%) compared to controls. By PND 28, F1 body weight, after adjustments for litter effects, was 10-13% lower than controls. Blood samples obtained on PND 28 showed no increases in frequencies of micronucleated immature erythrocytes in either F0 or F1 animals. In summary, doses of DON up to 3 mg/kg/day did not affect maternal survival or body weight. Doses of 3 mg/kg/day resulted in slight toxicity manifested as decreased body weight in the offspring. The no-observed effect level was 1 mg/kg/day.
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Affiliation(s)
- Madelyn C Huang
- Division of the National Toxicology Program, National Institute of Environmental Health Sciences, Research Triangle Park, NC, USA.
| | | | - Veronica G Robinson
- Division of the National Toxicology Program, National Institute of Environmental Health Sciences, Research Triangle Park, NC, USA
| | - Laura Betz
- Social and Scientific Systems, Durham, NC, USA
| | - Keith Shockley
- Division of Intramural Research, National Institute of Environmental Health Sciences, Research Triangle Park, NC, USA
| | - Helen Cunny
- Division of the National Toxicology Program, National Institute of Environmental Health Sciences, Research Triangle Park, NC, USA
| | - Kristine Witt
- Division of the National Toxicology Program, National Institute of Environmental Health Sciences, Research Triangle Park, NC, USA
| | - Suramya Waidyanatha
- Division of the National Toxicology Program, National Institute of Environmental Health Sciences, Research Triangle Park, NC, USA
| | - Dori Germolec
- Division of the National Toxicology Program, National Institute of Environmental Health Sciences, Research Triangle Park, NC, USA
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13
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Kluxen FM, Jensen SM. Expanding the toxicologist's statistical toolbox: Using effect size estimation and dose-response modelling for holistic assessments instead of generic testing. Regul Toxicol Pharmacol 2021; 121:104871. [PMID: 33485925 DOI: 10.1016/j.yrtph.2021.104871] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2020] [Revised: 12/21/2020] [Accepted: 01/19/2021] [Indexed: 12/25/2022]
Abstract
It is tempting to base (eco-)toxicological assay evaluation solely on statistical significance tests. The approach is stringent, objective and facilitates binary decisions. However, tests according to null hypothesis statistical testing (NHST) are thought experiments that rely heavily on assumptions. The generic and unreflected application of statistical tests has been called "mindless" by Gigerenzer. While statistical tests have an appropriate application domain, the present work investigates how unreflected testing may affect toxicological assessments. Dunnett multiple-comparison and Williams trend testing and their compatibility intervals are compared with dose-response-modelling in case studies, where data do not follow textbook behavior, nor behave as expected from a toxicological point of view. In such cases, toxicological assessments based only on p-values may be biased and biological evaluations based on plausibility may be prioritized. If confidence in a negative assay outcome cannot be established, further data may be needed for a robust toxicological assessment.
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Affiliation(s)
| | - Signe M Jensen
- Department of Plant and Environmental Sciences, University of Copenhagen, Copenhagen, Denmark
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14
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Alternatives to statistical decision trees in regulatory (eco-)toxicological bioassays. Arch Toxicol 2020; 94:1135-1149. [PMID: 32193567 DOI: 10.1007/s00204-020-02690-w] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2019] [Accepted: 02/25/2020] [Indexed: 12/24/2022]
Abstract
The goal of (eco-) toxicological testing is to experimentally establish a dose or concentration-response and to identify a threshold with a biologically relevant and probably non-random deviation from "normal". Statistical tests aid this process. Most statistical tests have distributional assumptions that need to be satisfied for reliable performance. Therefore, most statistical analyses used in (eco-)toxicological bioassays use subsequent pre- or assumption-tests to identify the most appropriate main test, so-called statistical decision trees. There are however several deficiencies with the approach, based on study design, type of tests used and subsequent statistical testing in general. When multiple comparisons are used to identify a non-random change against negative control, we propose to use robust testing, which can be generically applied without the need of decision trees. Visualization techniques and reference ranges also offer advantages over the current pre-testing approaches. We aim to promulgate the concepts in the (eco-) toxicological community and initiate a discussion for regulatory acceptance.
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15
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Fox JF, Denton DL, Diamond J, Stuber R. Comparison of false-positive rates of 2 hypothesis-test approaches in relation to laboratory toxicity test performance. ENVIRONMENTAL TOXICOLOGY AND CHEMISTRY 2019; 38:511-523. [PMID: 30776146 PMCID: PMC6869336 DOI: 10.1002/etc.4347] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/10/2018] [Revised: 08/18/2018] [Accepted: 12/18/2018] [Indexed: 06/09/2023]
Abstract
We compared 2 statistical hypothesis-test approaches (no-observed-effect concentration [NOEC] and test of significant toxicity [TST]) to determine the influence of laboratory test performance on the false-positive error rate using the US Environmental Protection Agency's Ceriodaphnia dubia reproduction whole-effluent toxicity (WET) test endpoint. Simulation and power calculations were used to determine error rates based on observed control coefficients of variation (CV) for 8 laboratories over a range of effect levels. Average C. dubia control reproduction among laboratories was 20 to 40 offspring per female, and the 75th percentile CV was 0.10 to 0.31, reflecting a range in laboratory performance. The 2 approaches behave similarly for CVs of 0.2 to 0.3. At effects <10%, as CV decreases, TST is less likely to declare toxicity and NOEC is more likely to do so. Laboratory performance affects whether a sample is declared toxic and influences the probability of false-positive (and -negative) error rates using either approach. At the 75th percentile control CV observed for each laboratory, 4 laboratories would achieve approximately a 5% false-positive rate using 13 or fewer replicates for this test method. For the remaining 4 laboratories, more replicates would be needed to achieve a 5% false-positive rate. The present analyses demonstrate how false-positive rates are influenced by laboratory performance and WET test design. Environ Toxicol Chem 2019;38:511-523. Published 2019 Wiley Periodicals Inc. on behalf of SETAC. This article is a US government work and, as such, is in the public domain in the United States of America.
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Affiliation(s)
- John F. Fox
- Office of Research and Development, US Environmental
Protection Agency, Washington, DC
| | - Debra L. Denton
- US Environmental Protection Agency, Region 9, Sacramento,
California
| | | | - Robyn Stuber
- US Environmental Protection Agency, Region 9, Sacramento,
California
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16
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Li X, Huo J, Liu Z, Yue Q, Zhang L, Gong Y, Chen J, Bao H. An updated weight of evidence approach for deriving a health-based guidance value for 4-nonylphenol. J Appl Toxicol 2018; 39:87-100. [PMID: 30027633 DOI: 10.1002/jat.3661] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2017] [Revised: 05/07/2018] [Accepted: 06/04/2018] [Indexed: 01/29/2023]
Affiliation(s)
- Xiaomeng Li
- West China School of Public Health and Healthy Food Evaluation Research Center; Sichuan University; Chengdu 610041 China
- Food Safety Monitoring and Risk Assessment Key Laboratory of Sichuan Province; Chengdu 610041 China
| | - Jiao Huo
- West China School of Public Health and Healthy Food Evaluation Research Center; Sichuan University; Chengdu 610041 China
- Food Safety Monitoring and Risk Assessment Key Laboratory of Sichuan Province; Chengdu 610041 China
| | - Zhaoping Liu
- China National Center for Food Safety Risk Assessment; Beijing 100022 China
| | - Qianlan Yue
- West China School of Public Health and Healthy Food Evaluation Research Center; Sichuan University; Chengdu 610041 China
- Food Safety Monitoring and Risk Assessment Key Laboratory of Sichuan Province; Chengdu 610041 China
| | - Lishi Zhang
- West China School of Public Health and Healthy Food Evaluation Research Center; Sichuan University; Chengdu 610041 China
- Food Safety Monitoring and Risk Assessment Key Laboratory of Sichuan Province; Chengdu 610041 China
| | - Yunyun Gong
- China National Center for Food Safety Risk Assessment; Beijing 100022 China
- School of Food Science and Nutrition; University of Leeds; Leeds LS2 9JT UK
| | - Jinyao Chen
- West China School of Public Health and Healthy Food Evaluation Research Center; Sichuan University; Chengdu 610041 China
- Food Safety Monitoring and Risk Assessment Key Laboratory of Sichuan Province; Chengdu 610041 China
| | - Huihui Bao
- China National Center for Food Safety Risk Assessment; Beijing 100022 China
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17
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Abstract
Study design, statistical analysis, interpretation of results, and conclusions should be a part of all research papers. Statistics are integral to each of these components and are therefore necessary to evaluate during manuscript peer review. Research published in Toxicological Pathology is often focused on animal studies that may seek to compare defined treatment groups in randomized controlled experiments or focus on the reliability of measurements and diagnostic accuracy of observed lesions from preexisting studies. Reviewers should distinguish scientific research goals that aim to test sufficient effect size differences (i.e., minimizing false positive rates) from common toxicologic goals of detecting a harmful effect (i.e., minimizing false negative rates). This journal comprises a wide range of study designs that require different kinds of statistical assessments. Therefore, statistical methods should be described in enough detail so that the experiment can be repeated by other research groups. The misuse of statistics will impede reproducibility.
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Affiliation(s)
- Keith R Shockley
- 1 Biostatistics and Computational Biology Branch, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, North Carolina, USA
| | - Grace E Kissling
- 1 Biostatistics and Computational Biology Branch, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, North Carolina, USA
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18
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Wieczorek MV, Bakanov N, Bilancia D, Szöcs E, Stehle S, Bundschuh M, Schulz R. Structural and functional effects of a short-term pyrethroid pulse exposure on invertebrates in outdoor stream mesocosms. THE SCIENCE OF THE TOTAL ENVIRONMENT 2018; 610-611:810-819. [PMID: 28826119 DOI: 10.1016/j.scitotenv.2017.08.048] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/13/2017] [Revised: 08/04/2017] [Accepted: 08/05/2017] [Indexed: 06/07/2023]
Abstract
Agricultural land-use frequently results in short pulse exposures of insecticides such as pyrethroids in river systems, adversely affecting local invertebrate communities. In order to assess insecticide-induced effects, stream mesocosms are used within higher tier aquatic risk assessment. Regulatory acceptable concentrations (RACs) derived from those studies are often higher compared with tier 1 RACs. Hence, the present mesocosm study evaluates this aspect using a pulse exposure scenario typical for streams and the pyrethroid insecticide etofenprox. A 6-h pulse exposure with measured concentrations of 0.04, 0.3 and 5.3μgL-1 etofenprox was used. We considered abundance, drift and emergence of invertebrates as structural endpoints and the in situ-measured feeding rates of the isopod Asellus aquaticus as functional endpoint. Most prominent effects were visible at 5.3μgL-1 etofenprox which caused adverse effects of up to 100% at the individual and population level, as well as community structure alterations. Transient effects were observed for invertebrate drift (effect duration ≤24h) and for the invertebrate community (9 days after exposure) at 0.3μgL-1 etofenprox. Furthermore, 0.04μgL-1 etofenprox affected the abundance of the mayfly Cloeon simile (decrease by 66%) and the feeding rate of A. aquaticus (decrease by 44%). Thus, implications for the functional endpoint leaf litter breakdown in heterotrophic ecosystems may be expected. A hypothetical RAC derived from the present mesocosm study (0.004μgL-1) is in line with the official tier 1 RAC (0.0044μgL-1) and thus shows that the present mesocosm study did not result in a higher RAC.
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Affiliation(s)
- Matthias V Wieczorek
- Institute for Environmental Sciences, University of Koblenz-Landau, Fortstrasse 7, 76829 Landau, Germany.
| | - Nikita Bakanov
- Institute for Environmental Sciences, University of Koblenz-Landau, Fortstrasse 7, 76829 Landau, Germany
| | - Daniel Bilancia
- Institute for Environmental Sciences, University of Koblenz-Landau, Fortstrasse 7, 76829 Landau, Germany
| | - Eduard Szöcs
- Institute for Environmental Sciences, University of Koblenz-Landau, Fortstrasse 7, 76829 Landau, Germany
| | - Sebastian Stehle
- Institute for Environmental Sciences, University of Koblenz-Landau, Fortstrasse 7, 76829 Landau, Germany
| | - Mirco Bundschuh
- Department of Aquatic Sciences and Assessment, Swedish University of Agricultural Sciences, Lennart Hjelms väg 9, 75007 Uppsala, Sweden
| | - Ralf Schulz
- Institute for Environmental Sciences, University of Koblenz-Landau, Fortstrasse 7, 76829 Landau, Germany
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19
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Melvin SD, Petit MA, Duvignacq MC, Sumpter JP. Towards improved behavioural testing in aquatic toxicology: Acclimation and observation times are important factors when designing behavioural tests with fish. CHEMOSPHERE 2017; 180:430-436. [PMID: 28419956 DOI: 10.1016/j.chemosphere.2017.04.058] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/01/2017] [Revised: 04/08/2017] [Accepted: 04/12/2017] [Indexed: 06/07/2023]
Abstract
The quality and reproducibility of science has recently come under scrutiny, with criticisms spanning disciplines. In aquatic toxicology, behavioural tests are currently an area of controversy since inconsistent findings have been highlighted and attributed to poor quality science. The problem likely relates to limitations to our understanding of basic behavioural patterns, which can influence our ability to design statistically robust experiments yielding ecologically relevant data. The present study takes a first step towards understanding baseline behaviours in fish, including how basic choices in experimental design might influence behavioural outcomes and interpretations in aquatic toxicology. Specifically, we explored how fish acclimate to behavioural arenas and how different lengths of observation time impact estimates of basic swimming parameters (i.e., average, maximum and angular velocity). We performed a semi-quantitative literature review to place our findings in the context of the published literature describing behavioural tests with fish. Our results demonstrate that fish fundamentally change their swimming behaviour over time, and that acclimation and observational timeframes may therefore have implications for influencing both the ecological relevance and statistical robustness of behavioural toxicity tests. Our review identified 165 studies describing behavioural responses in fish exposed to various stressors, and revealed that the majority of publications documenting fish behavioural responses report extremely brief acclimation times and observational durations, which helps explain inconsistencies identified across studies. We recommend that researchers applying behavioural tests with fish, and other species, apply a similar framework to better understand baseline behaviours and the implications of design choices for influencing study outcomes.
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Affiliation(s)
- Steven D Melvin
- Australian Rivers Institute, Griffith University, Southport, QLD, 4222, Australia.
| | - Marie A Petit
- Australian Rivers Institute, Griffith University, Southport, QLD, 4222, Australia
| | - Marion C Duvignacq
- Australian Rivers Institute, Griffith University, Southport, QLD, 4222, Australia
| | - John P Sumpter
- Institute for Environment, Health and Societies, Brunel University London, Uxbridge, Middlesex, UB8 3PH, United Kingdom
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20
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Tarazona JV, Court-Marques D, Tiramani M, Reich H, Pfeil R, Istace F, Crivellente F. Glyphosate toxicity and carcinogenicity: a review of the scientific basis of the European Union assessment and its differences with IARC. Arch Toxicol 2017; 91:2723-2743. [PMID: 28374158 PMCID: PMC5515989 DOI: 10.1007/s00204-017-1962-5] [Citation(s) in RCA: 192] [Impact Index Per Article: 27.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2017] [Accepted: 03/21/2017] [Indexed: 11/29/2022]
Abstract
Glyphosate is the most widely used herbicide worldwide. It is a broad spectrum herbicide and its agricultural uses increased considerably after the development of glyphosate-resistant genetically modified (GM) varieties. Since glyphosate was introduced in 1974, all regulatory assessments have established that glyphosate has low hazard potential to mammals, however, the International Agency for Research on Cancer (IARC) concluded in March 2015 that it is probably carcinogenic. The IARC conclusion was not confirmed by the EU assessment or the recent joint WHO/FAO evaluation, both using additional evidence. Glyphosate is not the first topic of disagreement between IARC and regulatory evaluations, but has received greater attention. This review presents the scientific basis of the glyphosate health assessment conducted within the European Union (EU) renewal process, and explains the differences in the carcinogenicity assessment with IARC. Use of different data sets, particularly on long-term toxicity/carcinogenicity in rodents, could partially explain the divergent views; but methodological differences in the evaluation of the available evidence have been identified. The EU assessment did not identify a carcinogenicity hazard, revised the toxicological profile proposing new toxicological reference values, and conducted a risk assessment for some representatives uses. Two complementary exposure assessments, human-biomonitoring and food-residues-monitoring, suggests that actual exposure levels are below these reference values and do not represent a public concern.
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Affiliation(s)
- Jose V Tarazona
- Pesticides Unit, European Food Safety Authority, Via Carlo Magno 1/A, 43126, Parma, Italy.
| | - Daniele Court-Marques
- Pesticides Unit, European Food Safety Authority, Via Carlo Magno 1/A, 43126, Parma, Italy
| | - Manuela Tiramani
- Pesticides Unit, European Food Safety Authority, Via Carlo Magno 1/A, 43126, Parma, Italy
| | - Hermine Reich
- Pesticides Unit, European Food Safety Authority, Via Carlo Magno 1/A, 43126, Parma, Italy
| | - Rudolf Pfeil
- Federal Institute for Risk Assessment (BfR), Berlin, Germany
| | - Frederique Istace
- Pesticides Unit, European Food Safety Authority, Via Carlo Magno 1/A, 43126, Parma, Italy
| | - Federica Crivellente
- Pesticides Unit, European Food Safety Authority, Via Carlo Magno 1/A, 43126, Parma, Italy
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21
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Moon SH, Kim D, Shimizu N, Okada T, Hitoe S, Shimoda H. Ninety-day oral toxicity study of rice-derived γ-oryzanol in Sprague-Dawley rats. Toxicol Rep 2016; 4:9-18. [PMID: 28959620 PMCID: PMC5615091 DOI: 10.1016/j.toxrep.2016.12.001] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2016] [Revised: 11/28/2016] [Accepted: 12/05/2016] [Indexed: 01/10/2023] Open
Abstract
A 90-day oral toxicity study of γ-oryzanol, a rice-derived triterpenoid ferulate, was performed by oral gavage administration to male and female Sprague-Dawley rats at doses of 0, 1000, and 2000 mg/kg body weight/day. All rats administered γ-oryzanol survived throughout the study period. Both male and female rats showed no toxicologically significant changes of the general signs, examination findings, body weight, food consumption, functional observational battery results, ophthalmological findings, urinalysis, hematology tests, clinical chemistry tests, organ weights, and necropsy findings. Moreover, there were no histopathological changes related to administration of γ-oryzanol in males and females from the 2000 mg/kg body weight/day group. In conclusion, the no observed adverse effect level (NOAEL) of γ-oryzanol exceeded 2000 mg/kg body weight/day for both male and female rats under the conditions of this study.
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Affiliation(s)
- Seol-Hee Moon
- Biotoxtech Co., Ltd., 53, Yeongudanji-ro, Ochang-eup, Cheongwon-gu, Cheongju-si, Chungcheongbuk-do, 363-883, Republic of Korea
| | - Duyeol Kim
- Biotoxtech Co., Ltd., 53, Yeongudanji-ro, Ochang-eup, Cheongwon-gu, Cheongju-si, Chungcheongbuk-do, 363-883, Republic of Korea
| | - Norihito Shimizu
- Oryza Oil & Fat Chemical Co. Ltd., 1 Numata, Kitagata-cho, Ichinomiya, Aichi 493-8001, Japan
| | - Tadashi Okada
- Oryza Oil & Fat Chemical Co. Ltd., 1 Numata, Kitagata-cho, Ichinomiya, Aichi 493-8001, Japan
| | - Shoketsu Hitoe
- Oryza Oil & Fat Chemical Co. Ltd., 1 Numata, Kitagata-cho, Ichinomiya, Aichi 493-8001, Japan
| | - Hiroshi Shimoda
- Oryza Oil & Fat Chemical Co. Ltd., 1 Numata, Kitagata-cho, Ichinomiya, Aichi 493-8001, Japan
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22
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Dalefield RR, Gosse MA, Mueller U. A 28-day oral toxicity study of echimidine and lasiocarpine in Wistar rats. Regul Toxicol Pharmacol 2016; 81:146-154. [PMID: 27546169 DOI: 10.1016/j.yrtph.2016.08.006] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2016] [Revised: 08/16/2016] [Accepted: 08/17/2016] [Indexed: 12/13/2022]
Abstract
Pyrrolizidine alkaloids (PAs) are a class of naturally-occurring plant toxins. Echimidine is one of the predominant PAs found in honeys produced in Australia and New Zealand. There is a lack of information on the oral toxicity of echimidine on which to base regulatory decisions concerning the risk to humans of these honeys. This GLP study was conducted to assess the subchronic dietary toxicity of echimidine to rats compared to that of lasiocarpine as a positive control. Wistar rats, 10/sex, were fed diets containing 0, 0.6, 1.2 or 2.5 mg/kg bw echimidine. Positive control groups, 10/sex, were fed diets containing 0.6, 1.2 or 2.5 mg/kg bw lasiocarpine. Neither PA had any effect on survival, food consumption, clinical signs, gross lesions, or histopathology. Consumption of lasiocarpine, but not echimidine, decreased bodyweight gain in males at ≥ 1.2 mg/kg bw, and in females at 2.5 mg/kg bw. Slight alterations in white cell counts and serum ALT concentrations at 2.5 mg/kg bw of both PAs were not clinically significant, had no histological correlates, and were considered to be of equivocal relevance. In conclusion, the subchronic No Observed Adverse Effect Level (NOAEL) for echimidine is 2.5 mg/kg bw/day, whereas, on the basis of a treatment-related decrease in bodyweight gain in males at 1.2 mg/kg bodyweight, the NOAEL for lasiocarpine is 0.6 mg/kg bw/day.
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Affiliation(s)
- Rosalind R Dalefield
- Food Standards Australia New Zealand, Level 3, 154 Featherston Street, Wellington 6011, 6143, New Zealand.
| | - Michelle A Gosse
- Food Standards Australia New Zealand, Level 3, 154 Featherston Street, Wellington 6011, 6143, New Zealand.
| | - Utz Mueller
- Food Standards Australia New Zealand, 55 Blackall Street, Barton, ACT 2600, Australia.
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23
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Baier B, Cordts R, Stei P. Influence of gender and body hemisphere on the occurrence of wavy ribs: An analysis of spontaneous skeletal abnormalities in Wistar rat fetuses. Reprod Toxicol 2016; 63:135-9. [DOI: 10.1016/j.reprotox.2016.05.020] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2016] [Revised: 05/17/2016] [Accepted: 05/27/2016] [Indexed: 12/26/2022]
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24
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Fox DR, Landis WG. Comment on ET&C perspectives, November 2015-A holistic view. ENVIRONMENTAL TOXICOLOGY AND CHEMISTRY 2016; 35:1337-1339. [PMID: 27216838 DOI: 10.1002/etc.3378] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/08/2015] [Revised: 01/15/2016] [Accepted: 01/21/2016] [Indexed: 06/05/2023]
Abstract
In response to a recent collection of perspectives published in Environmental Toxicology and Chemistry, the authors argue that there is little value in revisiting and rehashing the well-documented issues around toxicity metrics, competing statistical paradigms, legitimacy of theoretical constructs for species sensitivity distributions, and a number of other unresolved (and perhaps unresolvable) attendant statistical issues that have occupied journal space for more than 30 yr. This is not to say that these matters are unimportant-they are; however, the discussion on these topics is mature, with very few new insights being offered. To move forward on some of these seemingly intractable issues, the authors suggest the ecotoxicological community would be better served by the formation of a subdiscipline of "statistical ecotoxicology," where professional statisticians and ecotoxicologists work in unison. As it currently stands, statistical developments in ecotoxicology are not necessarily undertaken or peer-reviewed by professional statisticians, a situation that has no doubt contributed to the lack of real progress on important recommendations such as the phasing out of no-observed-effect concentrations. Environ Toxicol Chem 2016;35:1337-1339. © 2016 SETAC.
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Affiliation(s)
- David R Fox
- Environmetrics Australia, Victoria, Australia
- University of Melbourne, Melbourne, Victoria, Australia
| | - Wayne G Landis
- Institute of Environmental Toxicology, Huxley College of the Environment, Western Washington University, Bellingham, Washington, USA
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25
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Kim DE, Yang H, Jang WH, Jung KM, Park M, Choi JK, Jung MS, Jeon EY, Heo Y, Yeo KW, Jo JH, Park JE, Sohn SJ, Kim TS, Ahn IY, Jeong TC, Lim KM, Bae S. Predictive capacity of a non-radioisotopic local lymph node assay using flow cytometry, LLNA:BrdU–FCM: Comparison of a cutoff approach and inferential statistics. J Pharmacol Toxicol Methods 2016; 78:76-84. [DOI: 10.1016/j.vascn.2015.12.001] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2015] [Revised: 10/20/2015] [Accepted: 12/02/2015] [Indexed: 10/22/2022]
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26
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Berry C. The dangers of hazards. Toxicol Res (Camb) 2016; 5:373-376. [PMID: 30090352 PMCID: PMC6062252 DOI: 10.1039/c5tx00472a] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2015] [Accepted: 01/11/2016] [Indexed: 01/17/2023] Open
Abstract
Concerns about the quality and reproducibility of scientific papers have emphasised the uncertainty of observations in the biological sciences. Focussing on this problem in the types of science that often underlie regulations affecting population exposures has clear implications for regulatory studies. Recent comments on the IARC process of hazard identification in the field of carcinogenesis have identified problems in dealing with public information content and regulatory value of the Monograph system. What is the value of a system that does not clearly identify its methodology for defining a hazard and which does not provide realistic estimates of risk?
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Affiliation(s)
- Colin Berry
- Queen Mary - Pathology , London College Gardens , Dulwich , London SE21 7BE , UK .
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27
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Girardello F, Custódio Leite C, Vianna Villela I, da Silva Machado M, Luiz Mendes Juchem A, Roesch-Ely M, Neves Fernandes A, Salvador M, Antonio Pêgas Henriques J. Titanium dioxide nanoparticles induce genotoxicity but not mutagenicity in golden mussel Limnoperna fortunei. AQUATIC TOXICOLOGY (AMSTERDAM, NETHERLANDS) 2016; 170:223-228. [PMID: 26675368 DOI: 10.1016/j.aquatox.2015.11.030] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/30/2015] [Revised: 11/26/2015] [Accepted: 11/28/2015] [Indexed: 06/05/2023]
Abstract
The widespread use of titanium dioxide nanoparticles (TiO2-NP) in consumer products is the cause of its appearance in wastewater and effluents, reaching the aquatic environment. The evaluation of the biological impact of TiO2-NP and the need to understand its ecotoxicological impact to the aquatic ecosystem are of major concern. Bivalve mollusks may represent a target group for nanoparticle toxicity. Limnoperna fortunei (golden mussel), a freshwater bivalve organism that has been employed in biomonitoring environmental conditions. Comet assay, micronucleus test and oxidative damage to lipids and proteins were performed after the golden mussel was exposed to TiO2-NP (1, 5, 10 and 50μgmL(-1)). The results demonstrate that TiO2-NP can damage the DNA of haemocytes after 2h of exposure and the genotoxic activity significantly increased after 4h exposure to TiO2-NP, at all the TiO2-NP concentrations. TiO2-NP was ineffective in causing mutagenicity in the haemolymph cells of golden mussel. The increase in the lipid peroxidation levels and carbonyl proteins after the exposure to TiO2-NP indicates the induction of oxidative stress at 2h exposure with similar results to all TiO2-NP concentrations, but these effects did not occur at 4h exposure. These results demonstrated that, although TiO2-NP is not mutagenic to golden mussel, it does induce DNA damage and oxidative stress in these organisms.
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Affiliation(s)
- Francine Girardello
- Institute of Biotechnology, University of Caxias do Sul (UCS), Rua Francisco Getúlio Vargas 1130, 95070-560 Caxias do Sul, RS, Brazil.
| | - Camila Custódio Leite
- Institute of Biotechnology, University of Caxias do Sul (UCS), Rua Francisco Getúlio Vargas 1130, 95070-560 Caxias do Sul, RS, Brazil
| | - Izabel Vianna Villela
- InnVitro Research and Development, Rua Mariante 180, Sala 902, 90430-180 Porto Alegre, RS, Brazil
| | - Miriana da Silva Machado
- InnVitro Research and Development, Rua Mariante 180, Sala 902, 90430-180 Porto Alegre, RS, Brazil; Department of Biophysics/Center of Biotechnology, Federal University of Rio Grande do Sul (UFRGS), Av. Bento Gonçalves 9500, Campus do Vale Setor 4, P.O. Box 43422, 91501-970 Porto Alegre, RS, Brazil
| | - André Luiz Mendes Juchem
- Department of Biophysics/Center of Biotechnology, Federal University of Rio Grande do Sul (UFRGS), Av. Bento Gonçalves 9500, Campus do Vale Setor 4, P.O. Box 43422, 91501-970 Porto Alegre, RS, Brazil
| | - Mariana Roesch-Ely
- Institute of Biotechnology, University of Caxias do Sul (UCS), Rua Francisco Getúlio Vargas 1130, 95070-560 Caxias do Sul, RS, Brazil
| | - Andreia Neves Fernandes
- Institute of Chemistry, Federal University of Rio Grande do Sul (UFRGS), Av. Bento Gonçalves 9500, P.O. Box 15003, 91501-970 Porto Alegre, RS, Brazil
| | - Mirian Salvador
- Institute of Biotechnology, University of Caxias do Sul (UCS), Rua Francisco Getúlio Vargas 1130, 95070-560 Caxias do Sul, RS, Brazil
| | - João Antonio Pêgas Henriques
- Institute of Biotechnology, University of Caxias do Sul (UCS), Rua Francisco Getúlio Vargas 1130, 95070-560 Caxias do Sul, RS, Brazil; InnVitro Research and Development, Rua Mariante 180, Sala 902, 90430-180 Porto Alegre, RS, Brazil; Department of Biophysics/Center of Biotechnology, Federal University of Rio Grande do Sul (UFRGS), Av. Bento Gonçalves 9500, Campus do Vale Setor 4, P.O. Box 43422, 91501-970 Porto Alegre, RS, Brazil
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28
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Fabbrocini A, D'Adamo R, Del Prete F, Maurizio D, Specchiulli A, Oliveira LFJ, Silvestri F, Sansone G. The sperm motility pattern in ecotoxicological tests. The CRYO-Ecotest as a case study. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2016; 123:53-59. [PMID: 26318919 DOI: 10.1016/j.ecoenv.2015.08.018] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/16/2015] [Revised: 07/16/2015] [Accepted: 08/17/2015] [Indexed: 06/04/2023]
Abstract
Changes in environmental stressors inevitably lead to an increasing need for innovative and more flexible monitoring tools. The aim of this work has been the characterization of the motility pattern of the cryopreserved sea bream semen after exposure to a dumpsite leachate sample, for the identification of the best representative parameters to be used as endpoints in an ecotoxicological bioassay. Sperm motility has been evaluated either by visual and by computer-assisted analysis; parameters concerning motility on activation and those describing it in the times after activation (duration parameters) have been assessed, discerning them in terms of sensitivity, reliability and methodology of assessment by means of multivariate analyses. The EC50 values of the evaluated endpoints ranged between 2.3 and 4.5ml/L, except for the total motile percentage (aTM, 7.0ml/L), which proved to be the less sensitive among all the tested parameters. According to the multivariate analyses, a difference in sensitivity among "activation" endpoints in respect of "duration" ones can be inferred; on the contrary, endpoints seem to be equally informative either describing total motile sperm or the rapid sub-population, as well as the assessment methodology seems to be not discriminating. In conclusion, the CRYO-Ecotest is a multi-endpoint bioassay that can be considered a promising innovative ecotoxicological tool, characterized by a high plasticity, as its endpoints can be easy tailored each time according to the different needs of the environmental quality assessment programs.
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Affiliation(s)
- Adele Fabbrocini
- Consiglio Nazionale delle Ricerche, Istituto di Scienze Marine, UOS Lesina (FG), Italy.
| | - Raffaele D'Adamo
- Consiglio Nazionale delle Ricerche, Istituto di Scienze Marine, UOS Lesina (FG), Italy
| | | | - Daniela Maurizio
- Consiglio Nazionale delle Ricerche, Istituto di Scienze Marine, UOS Lesina (FG), Italy
| | | | - Luis F J Oliveira
- Instituto Oceanográfico - USP, São Paulo, Brazil; The Capes Foundation - Ministry of Education of Brazil, Brasília, DF, Brazil
| | - Fausto Silvestri
- Dipartimento di Biologia, Università degli Studi Federico II, Napoli, Italy; FIPERJ - Fundação Instituto de Pesca do Estado do Rio de Janeiro, Centro Angra dos Reis (RJ), Brazil
| | - Giovanni Sansone
- Dipartimento di Biologia, Università degli Studi Federico II, Napoli, Italy
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Zeller A, Tang L, Dertinger SD, Funk J, Duran-Pacheco G, Guérard M. A proposal for a novel rationale for critical effect size in dose–response analysis based on a multi-endpointin vivostudy with methyl methanesulfonate. Mutagenesis 2015; 31:239-53. [DOI: 10.1093/mutage/gev077] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Szöcs E, Schäfer RB. Ecotoxicology is not normal: A comparison of statistical approaches for analysis of count and proportion data in ecotoxicology. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2015; 22:13990-13999. [PMID: 25953608 DOI: 10.1007/s11356-015-4579-3] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/13/2015] [Accepted: 04/21/2015] [Indexed: 06/04/2023]
Abstract
Ecotoxicologists often encounter count and proportion data that are rarely normally distributed. To meet the assumptions of the linear model, such data are usually transformed or non-parametric methods are used if the transformed data still violate the assumptions. Generalized linear models (GLMs) allow to directly model such data, without the need for transformation. Here, we compare the performance of two parametric methods, i.e., (1) the linear model (assuming normality of transformed data), (2) GLMs (assuming a Poisson, negative binomial, or binomially distributed response), and (3) non-parametric methods. We simulated typical data mimicking low replicated ecotoxicological experiments of two common data types (counts and proportions from counts). We compared the performance of the different methods in terms of statistical power and Type I error for detecting a general treatment effect and determining the lowest observed effect concentration (LOEC). In addition, we outlined differences on a real-world mesocosm data set. For count data, we found that the quasi-Poisson model yielded the highest power. The negative binomial GLM resulted in increased Type I errors, which could be fixed using the parametric bootstrap. For proportions, binomial GLMs performed better than the linear model, except to determine LOEC at extremely low sample sizes. The compared non-parametric methods had generally lower power. We recommend that counts in one-factorial experiments should be analyzed using quasi-Poisson models and proportions from counts by binomial GLMs. These methods should become standard in ecotoxicology.
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Affiliation(s)
- Eduard Szöcs
- Institute for Environmental Sciences, University of Koblenz-Landau, Fortstraße 7, 76829, Landau, Germany,
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Yang H, Na J, Jang WH, Jung MS, Jeon JY, Heo Y, Yeo KW, Jo JH, Lim KM, Bae S. Appraisal of within- and between-laboratory reproducibility of non-radioisotopic local lymph node assay using flow cytometry, LLNA:BrdU-FCM: Comparison of OECD TG429 performance standard and statistical evaluation. Toxicol Lett 2015; 234:172-9. [DOI: 10.1016/j.toxlet.2015.02.014] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2014] [Revised: 02/15/2015] [Accepted: 02/18/2015] [Indexed: 10/23/2022]
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Kuper CF, Vogels J, Kemmerling J, Fehlert E, Rühl-Fehlert C, Vohr HW, Krul C. Integrated analysis of toxicity data of two pharmaceutical immunosuppressants and two environmental pollutants with immunomodulating properties to improve the understanding of side effects-A toxicopathologist׳s view. Eur J Pharmacol 2015; 759:343-55. [PMID: 25824899 DOI: 10.1016/j.ejphar.2015.03.045] [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] [Received: 01/27/2015] [Revised: 02/03/2015] [Accepted: 03/12/2015] [Indexed: 12/19/2022]
Abstract
Data in a toxicity test are evaluated generally per parameter. Information on the response per animal in addition to per parameter can improve the evaluation of the results. The results from the six studies in rats, described in the paper by Kemmerling, J., Fehlert, E., Rühl-Fehlert, C., Kuper, C.F., Stropp, G., Vogels, J., Krul, C., Vohr, H.-W., 2015. The transferability from rat subacute 4-week oral toxicity study to translational research exemplified by two pharmaceutical immunosuppressants and two environmental pollutants with immunomodulating properties (In this issue), have been subjected to principal component analysis (PCA) and principal component discriminant analysis (PC-DA). The two pharmaceuticals azathioprine (AZA) and cyclosporine A (CSA) and the two environmental pollutants hexachlorobenzene (HCB) and benzo(a)pyrene (BaP) all modulate the immune system, albeit that their mode of immunomodulation is quite diverse. PCA illustrated the similarities between the two independent studies with AZA (AZA1 and AZA2) and CSA (CSA1 and CSA2). The PC-DA on data of the AZA2 study did not increase substantially the information on dose levels. In general, the no-effect levels were lower upon single parameter analysis than indicated by the distances between the dose groups in the PCA. This was mostly due to the expert judgment in the single parameter evaluation, which took into account outstanding pathology in only one or two animals. The PCA plots did not reveal sex-related differences in sensitivity, but the key pathology for males and females differed. The observed variability in some of the control groups was largely a peripheral blood effect. Most importantly, PCA analysis identified several animals outside the 95% confidence limit indicating high-responders; also low-to-non-responders were identified. The key pathology enhanced the understanding of the response of the animals to the four model compounds.
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Affiliation(s)
| | - Jack Vogels
- TNO, PO Box 360, 3700 AJ Zeist, The Netherlands
| | - Jessica Kemmerling
- Bayer Pharma AG, GDD-GED-TOX-IT-Immunotoxicology, Aprather Weg, 42096 Wuppertal, Germany
| | - Ellen Fehlert
- Department of Medicine IV, Eberhard-Karls University, Otfried-Mueller Strasse 10, 72076 Tuebingen, Germany
| | | | - Hans-Werner Vohr
- Bayer Pharma AG, GDD-GED-TOX-IT-Immunotoxicology, Aprather Weg, 42096 Wuppertal, Germany
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