Regulatory Testing Research Articles

Applicability of nanomaterial-specific guidelines within long-term Daphnia magna toxicity assays: A case study on multigenerational effects of nTiO2 and nCeO2 exposure in the presence of artificial daylight

In recent years, various ecotoxicological test guidelines and (technical) guidance documents have been evaluated and updated with regard to their applicability to nanomaterials (NMs). Several of these have currently reached official regulatory status. Ensuring their harmonized implementation with previously recognized methods for ecotoxicity testing of chemicals is a crucial next step towards effective and efficient regulation of NMs. In the present study, we evaluated the feasibility of assessing multigenerational effects in the first generation of offspring derived from exposed Daphnia magna whilst maintaining test conditions in accordance with regulatory test guidelines and guidance documents for NMs. To do so, we integrated the recommendations for ecotoxicological testing of NMs as defined in OECD Guidance Document 317 into an extended long-term D. magna reproduction test method (OECD Test Guideline 211) and assessed effects of two poorly soluble NMs (nTiO2 and nCeO2). Our results show adverse effects on life-history parameters of D. magna exposed to the selected nanomaterials within the range of reported environmental concentrations. We argue that conforming to OECD test guidelines and accompanying guidance for nanomaterials is feasible when performing D. magna reproduction tests and can minimize unnecessary duplication of similar experiments, even when extensions to the standardized test setup are added.

Caenorhabditis elegans Neurotoxicity Testing: Novel Applications in the Adverse Outcome Pathway Framework.

Neurological hazard assessment of industrial and pesticidal chemicals demands a substantial amount of time and resources. Caenorhabditis elegans is an established model organism in developmental biology and neuroscience. It presents an ideal test system with relatively fewer neurons (302 in hermaphrodites) versus higher-order species, a transparent body, short lifespan, making it easier to perform neurotoxic assessment in a time and cost-effective manner. Yet, no regulatory testing guidelines have been developed for C. elegans in the field of developmental and adult neurotoxicity. Here, we describe a set of morphological and behavioral assessment protocols to examine neurotoxicity in C. elegans with relevance to cholinergic and dopaminergic systems. We discuss the homology of human genes and associated proteins in these two signaling pathways and evaluate the morphological and behavioral endpoints of C. elegans in the context of published adverse outcome pathways of neurodegenerative diseases. We conclude that C. elegans neurotoxicity testing will not only be instrumental to eliminating mammalian testing in neurological hazard assessment but also lead to new knowledge and mechanistic validation in the adverse outcome pathway framework.

Determination of Highly Polar and Ionic Pesticides in Grape and Pomegranate Using Liquid Chromatography Tandem Mass Spectrometry.

Residues of polar pesticides cannot be determined by QuEChERS-based multiresidue extractions because of their non-amenability to reverse-phase chromatographic separation and poor recoveries. On the other hand, single-residue methods pose limitations because of the various requirements of sample preparation and LC-MS/MS conditions. A new multiresidue method is thus warranted for rapid and simultaneous analysis of polar pesticides. The study developed a multiresidue method for the simultaneous analysis of glyphosate and its metabolite (aminomethylphosphonic acid, AMPA), glufosinate and its metabolites (3-methylphosphinicopropionic acid and N-acetyl-glufosinate), ethephon, fosetyl-aluminum and its metabolite (phosphonic acid), and trimesium in grape and pomegranate by LC-MS/MS. The homogenized samples (10 g) were extracted with acidified methanol (20 mL). An aliquot of the extract was diluted with acetonitrile (1 + 1) and measured by LC-MS/MS using a Torus DEA column. The performance of a hydrophilic interaction liquid chromatography (HILIC) column and an "anionic polar pesticides" (APP) column was also evaluated. The method performance on the Torus DEA column was satisfactory for all compounds (recoveries = 77-104%, repeatability-RSD, <11%) at limit of quantification (LOQ) (0.01 mg/kg), and with higher levels in grape and pomegranate. The only exception was AMPA, which had an LOQ of 0.05 mg/kg. In the APP column, AMPA could be determined with an LOQ of 0.01 mg/kg. Trimesium, which had poor retention in Torus DEA, performed better in an XBridge HILIC column (retention time = 4.2 min, LOQ = 0.01 mg/kg). The inter-laboratory validation experiment yielded comparable results with high accuracy and precision. The method could screen the residues of all compounds on a Torus DEA column. For AMPA and trimesium, the APP and XBridge HILIC columns provided superior method performances. Since isotopically labeled internal standards were not required, the method appeared cost-effective. Considering its compliance with the SANTE/12682/2019 validation guidelines and EU-MRLs, the method can be recommended for regulatory testing purposes. A high-throughput residue analysis method targeting nine polar and ionic compounds in grape and pomegranate involved a single multiresidue extraction, followed by direct analysis using LC-MS/MS. A satisfactory method performance was achieved through intra- and inter-laboratory validation. The method sensitivity met the EU-MRLs and the SANTE/12682/2019 analytical quality control criteria.

True Grit: A Story of Perseverance Making Two Out of Three the First Non-Animal Testing Strategy (Adopted as OECD Guideline No. 497)

In the last two decades, great strides have been made in developing alternative methods to animal testing for regulatory and safety testing. In 2021, a breakthrough in regulatory testing was achieved in that the first test strategies employing non-animal test methods for skin sensitization have been accepted as OECD guideline 497, which falls under the mutual acceptance of data (MAD) by OECD member states. Achieving this goal was a story of hard work and perseverance of the many people involved. This review gives an overview of some of the many aspects and timelines this entailed—just from the perspective of one stakeholder. In the end, the true grit of all involved allowed us to achieve not only a way forward in using test strategies for skin sensitization, but also a new approach to address other complex toxicological effects without the use of animals in the future.

Environmental fate studies with 14C-polyoxyethylene tallow amine (POE-T) to characterize environmental exposure and inform environmental risk assessments

Polyoxyethylene tallow amine (POE-T) is a member of the polyoxyethylene alkylamine (POEA) class of nonionic surfactants and is a component of some glyphosate-based formulations. The presence of POE-T improves foliar uptake of glyphosate in weeds, thereby reducing the amount of glyphosate needed for weed control. To further characterize the environmental fate of POE-T, aerobic soil degradation, hydrolysis, adsorption/desorption, and aerobic aquatic degradation studies were conducted according to U.S. EPA and OECD pesticide regulatory testing guidelines. POE-T labeled with carbon-14 was used in the studies to aid in analysis, assess mineralization to CO2, and allow for mass balance determinations. The aerobic soil half-lives (DT50) for POE-T ranged from 20 to 166 days with DT50 values increasing with increasing soil percent organic carbon (OC). POE-T was hydrolytically stable at pH 4–9. POE-T adsorbed strongly to soil (KFocads = 17,600–114,000) with sorption generally increasing as soil percent OC increased. The aerobic aquatic (water-sediment) system DT50s for POE-T were 14–29 days, with POE-T dissipating from the water column with DT50s of 0.10–0.12 days through metabolism and adsorption to sediment. Based on these results, aquatic organisms are unlikely to be exposed to POE -T in the water column for more than a few hours following waterborne exposure and sediment is a significant sink for POE-T in aquatic systems. However, bioavailability of POE-T in sediment and soil is predicted to be low based on strong adsorption and it is not readily desorbed.

Measurement of black carbon emissions from multiple engine and source types using laser-induced incandescence: sensitivity to laser fluence

Abstract. A new regulatory standard for non-volatile particulate matter (nvPM) mass-based emissions from aircraft engines has been adopted by the International Civil Aviation Organisation. One of the instruments used for the regulatory nvPM mass emissions measurements in aircraft engine certification tests is the Artium Technologies LII 300, which is based on laser-induced incandescence. The LII 300 response has been shown in some cases to vary with the type of black carbon particle measured. Hence it is important to identify a suitable black carbon emission source for instrument calibration. In this study, the relationship between the nvPM emissions produced by different engine sources and the response of the LII 300 instrument utilising the auto-compensating laser-induced incandescence (AC-LII) method was investigated. Six different sources were used, including a turboshaft helicopter engine, a diesel generator, an intermediate pressure test rig of a single-sector combustor, an auxiliary power unit gas turbine engine, a medium-sized diesel engine, and a downsized turbocharged direct-injection gasoline engine. Optimum LII 300 laser fluence levels were determined for each source and operating condition evaluated. It was found that an optimised laser fluence can be valid for real-time measurements from a variety of sources, where the mass concentration was independent of laser fluence levels covering the typical operating ranges for the various sources. However, it is important to perform laser fluence sweeps to determine the optimum fluence range as differences were observed in the laser fluence required between sources and fuels. We discuss the measurement merits, variability, and best practices in the real-time quantification of nvPM mass concentration using the LII 300 instrument and compare that with other diagnostic techniques, namely absorption-based methods such as photoacoustic spectroscopy (using a photoacoustic extinctiometer, PAX, and a micro soot sensor, MSS) and thermal-optical analysis (TOA). Particle size distributions were also measured using a scanning mobility particle sizer (SMPS). Overall, the LII 300 provides robust and consistent results when compared with the other diagnostic techniques across multiple engine sources and fuels. The results from this study will inform the development of updated calibration protocols to ensure repeatable and reproducible measurements of nvPM mass emissions from aircraft engines using the LII 300.

Regulatory Testing for Endocrine Disruptors; Need for Validated Methods and Integrated Approaches

Regulatory Testing for Endocrine Disruptors; Need for Validated Methods and Integrated Approaches

Return on investment on artificial intelligence: The case of bank capital requirement

Taking advantage of granular data we measure the change in bank capital requirement resulting from the implementation of AI techniques to predict corporate defaults. For each of the largest banks operating in France we build by an algorithm pseudo-internal models of credit risk management for a range of methodologies extensively used in AI (random forest, gradient boosting, ridge regression, neural network). We compare these models to the traditional model usually in place that basically relies on a combination of logistic regression and expert judgement. The comparison is made along two sets of criterias capturing: the ability to pass compliance tests used by the regulators during on-site missions of model validation (i), and the induced changes in capital requirement (ii). The different models show noticeable differences in their ability to pass the regulatory tests and to lead to a reduction in capital requirement. While displaying a similar ability than the traditional model to pass compliance tests, neural networks provide the strongest incentive for banks to apply AI models for their internal model of credit risk of corporate businesses as they lead in some cases to sizeable reduction in capital requirement.

Semiparametric GARCH models with long memory applied to value-at-risk and expected shortfall

In this paper new semiparametric GARCH models with long memory are in- troduced. The estimation of the nonparametric scale function is carried out by an adapted version of the SEMIFAR algorithm (Beran et al., 2002). Recurring on the revised recommendations by the Basel Committee to measure market risk in the banks' trading books (Basel Committee on Banking Supervision, 2013), the semi- parametric GARCH models are applied to obtain rolling one-step ahead forecasts for the Value at Risk (VaR) and Expected Shortfall (ES) for market risk assets. In addition, standard regulatory traffic light tests (Basel Committee on Banking Supervision, 1996) and a newly introduced traffic light test for the ES are carried out for all models. The practical relevance of our proposal is demonstrated by a comparative study. Our results indicate that semiparametric long memory GARCH models are an attractive alternative to their conventional, parametric counterparts.

Using R in Regulatory Toxicology.

Statistical analyses are an essential part of regulatory toxicological evaluations. While projects would be ideally monitored by both toxicologists and statisticians, this is often not possible in practice. Hence, toxicologists should be trained in some common statistical approaches but also need a tool for statistical evaluations. Due to transparency needed in regulatory processes and standard tests that can be evaluated with template approaches, the freely available open-source statistical software R may be suitable. R is a well-established software in the statistical community. The principal input method is via software code, which is both benefit and weakness of the tool. It is increasingly used by regulating authorities globally and can be easily extended by software packages, e.g., for new statistical functions and features. This manuscript outlines how R can be used in regulatory toxicology, allowing toxicologists to perform all regulatory required data evaluations in a single software solution. Practical applications are shown in case studies on simulated and experimental data. The examples cover a) Dunnett testing of treatment groups against a common control and in relation to a biological relevance threshold, assessing the test's assumptions and plotting the results; b) dose-response analysis and benchmark dose derivation for chronic kidney inflammation as a function of Pyridine; and c) graphical/exploratory data analysis of previously published developmental neurotoxicity data for Chlorpyrifos.

The Regulatory Evaluation of Vaccines for Human Use.

A vaccine is an immunogen, the administration of which is intended to stimulate the immune system to prevent, ameliorate, or treat a disease or infection. A vaccine may be a live attenuated preparation of microorganisms, inactivated (killed) whole organisms, living irradiated cells, crude fractions, or purified immunogens, including those derived from recombinant DNA in a host cell, conjugates formed by covalent linkage of components, synthetic antigens, polynucleotides (such as the plasmid DNA vaccines), mRNA, living vectored cells expressing specific heterologous immunogens, or cells pulsed with immunogen. Vaccines are highly complex products that differ from small molecule drugs because of the biological nature of the source materials such as those derived from microorganisms as well as the various cell substrates from which some are derived. Regardless of the technology used, because of their complexities, vaccines must undergo extensive testing and characterization. Special expertise and procedures are required for the manufacture, control, and regulation of vaccines. Throughout their life cycle from preclinical evaluation to post-licensure lot release testing, vaccines are subject to rigorous testing and oversight by manufacturers and national regulatory authorities. In this chapter, an overview of the regulatory evaluation and testing requirements for vaccines is presented.

Model of deformation growth dynamics during filled polymer materials mechanical tests under cable production conditions

With the introduction into highly filled halogen-free plastics production, the mechanical strength of which in operation directly depends on the flame retardant content and application technology, it becomes important to control the cable sheath mechanical characteristics in a fireproof design. Polymeric materials and their compositions are viscoelastic materials for which the mechanical properties depend on the stress time. The results of estimating the deformation samples rate elongation from the uniaxial stretching time at different dilution rates of the clamps in the mechanical characteristics determining process for halogen-free cable plastics in regulatory tests under production conditions are presented. It is shown that the inner and outer layers of the halogen-free plastic cable sheath have significantly different values of the plasticity normative parameter: differences evidence in the polymer structure in the inner and outer layers of the sheath due to the forced deformation process during extrusion, which is forced polymer structure orientation. Elongation relative deformation experimental dependences δL(t) of the samples on the uniaxial stretching time at different clamps dilution speeds are given, which illustrate confirmed by a large data array the dependencies shape reproducibility δL(t) for different in structure similar filled halogen-free polymers. The strain rate dependence model on tensile time as the sum of instantaneous-elastic, viscoelastic and instantaneous-plastic (irreversible) is proposed: dε/dt = λпр exp ( – t/λпр) + {∫ λ1 exp(–τ/λ1).exp[–(t–τ)/λ2]dτ]}/Δt. The appropriate parameter estimates of the named samples deformation components obtained by approximating the experimental data by the proposed model are given. The proposed model, firstly, explains the presence characteristic relative deformation maximum (t = tm) as a two interdependent deformation processes superposition with different aftermath λ. Secondly, it allows to specify the requirements for testing: with increasing the clamps dilution speed, the maximum time tm decreases significantly, respectively, the higher the clamps dilution speed, the smaller interval time Δt between a successive sample control section length measurements. This conclusion was experimentally confirmed for a specific material at a speed of 250 mm/min

Safety of Uncrossmatched ABO-Compatible RBCs in Alloimmunized Patients with Bleeding: Data from Two Decades: Results of a Systematic Analysis in 6,109 Patients

Introduction: Uncrossmatched ABO-compatible red blood cells (RBCs) are generally recommended in patients with life-threatening massive bleeding. There is little data regarding RBC transfusion when patients are transfused against clinically significant alloantibodies because compatible RBCs are not immediately available. Methods/Patients: All patients reviewed in this study (n = 6,109) required emergency blood transfusion and were treated at the Charité – Universitätsmedizin Berlin between 2001 and 2015. Primary uncrossmatched O Rh(D)-positive or -negative RBC units were immediately transfused prior to complete regulatory serological testing including determination of ABO group, Rhesus antigens, antibody screening, and crossmatching. Results: Without any significant change in the protocol of emergency transfusion of RBCs, a total of 63,373 RBC units were transfused in 6,109 patients. Antibody screening was positive in 413 patients (6.8%), and 19 of these patients received RBC units against clinically significant alloantibodies. None of these patients appeared to have developed significant hemolysis, and only one patient with anti-D seems to have developed signs of insignificant hemolysis following the transfusion of three Rh(D)-positive units. One patient who had anti-Jk^a received unselected units and did not develop a hemolytic transfusion reaction. Conclusion: Transfusion of uncrossmatched ABO-compatible RBCs against alloantibodies is highly safe in patients with life-threatening hemorrhage.

No evidence of effects or interaction between the widely used herbicide, glyphosate, and a common parasite in bumble bees.

BackgroundGlyphosate is the world’s most used pesticide and it is used without the mitigation measures that could reduce the exposure of pollinators to it. However, studies are starting to suggest negative impacts of this pesticide on bees, an essential group of pollinators. Accordingly, whether glyphosate, alone or alongside other stressors, is detrimental to bee health is a vital question. Bees are suffering declines across the globe, and pesticides, including glyphosate, have been suggested as being factors in these declines.MethodsHere we test, across a range of experimental paradigms, whether glyphosate impacts a wild bumble bee species, Bombus terrestris. In addition, we build upon existing work with honey bees testing glyphosate-parasite interactions by conducting fully crossed experiments with glyphosate and a common bumble bee trypanosome gut parasite, Crithidia bombi. We utilised regulatory acute toxicity testing protocols, modified to allow for exposure to multiple stressors. These protocols are expanded upon to test for effects on long term survival (20 days). Microcolony testing, using unmated workers, was employed to measure the impacts of either stressor on a proxy of reproductive success. This microcolony testing was conducted with both acute and chronic exposure to cover a range of exposure scenarios.ResultsWe found no effects of acute or chronic exposure to glyphosate, over a range of timespans post-exposure, on mortality or a range of sublethal metrics. We also found no interaction between glyphosate and Crithidia bombi in any metric, although there was conflicting evidence of increased parasite intensity after an acute exposure to glyphosate. In contrast to published literature, we found no direct impacts of this parasite on bee health. Our testing focussed on mortality and worker reproduction, so impacts of either or both of these stressors on other sublethal metrics could still exist.ConclusionsOur results expand the current knowledge on glyphosate by testing a previously untested species, Bombus terrestris, using acute exposure, and by incorporating a parasite never before tested alongside glyphosate. In conclusion our results find that glyphosate, as an active ingredient, is unlikely to be harmful to bumble bees either alone, or alongside Crithidia bombi.

Challenges of Conducting Point-Of-Care Testing Operations During The COVID-19 Pandemic In The Municipal Public Health System Based Ambulatory Care And School Health Clinics In New York City

Introduction/ObjectiveOur New York City Municipal Public Health System based multisite ambulatory clinics and school-based clinics, offer various waived POCT (point of care tests) and provider performed microscopy (PPM). To ensure standardization and quality of POC testing across our health system, our laboratory service conducts system wide centralized implementation, monitoring and oversight of the POCT operations in regard to regulatory compliance, test performance, quality control and training. With the emergence of the COVID-19 infection in the New York City, like all other clinical laboratories, our ambulatory care clinics encountered numerous hurdles and challenges. Here we elaborated the issues that we encountered and how we managed to overcome during the COVID-19 Pandemic.Methods/Case ReportWe categorized the challenges that affected our managers as well as field level laboratory operations and have devised a plane to deal with COVID-19 related predicaments.Results (if a Case Study enter NA)Among the staffing issues, staff relocation to the acute care hospital laboratories during the peak of the pandemic caused massive delay or cessation of POCT operations in our ambulatory care clinics. Manual result entry, for COVID-19 testing, at the patient portals due to lack of interface with the reference testing labs, staff shortages and frequent absences due to illness and fatigue were primary issues noted at technical level. Furthermore, there were notable delays in the processing of paper works and new staff recruitments. The lack of and significant delays in the critical laboratory supplies was another major management issue.ConclusionGiven the vastness and complexity of our multisite ambulatory care network, the COVID -19 pandemic impacted our ambulatory care clinic POCT operation in a very challenging way. However, our timeliness, coordinated interventions, close communications and initiatives handled the obstacles that arose very effectively to the ensure quality of POC testing, patient safety and quality care across our health system.

Ensuring Standardization, Quality Management And Improvement Of Point-Of-Care Testing In The Municipal Public Health System Based Ambulatory Care And School Health Clinics In New York City

Introduction/ObjectiveOperated under different acute care hospital clinical laboratory limited-service laboratory (LSL) licenses, our New York City five borough spanning multisite ambulatory clinics and school-based clinics have been offering various waived point-of-care tests (POCTs) and provider-performed microscopy (PPM) to the local communities. A wide range of variability existed among the clinics concerning regulatory compliance, test performance, quality control and training. To ensure standardization and quality of POCT across the health system, our laboratory service adopted and implemented a plan for systemwide LSL transfer from the acute care hospitals to ambulatory care laboratory service for centralized implementation, monitoring, and oversight of the POCT operations.Methods/Case ReportHaving over 60 clinics, while transferring the LSLs, we chose multi-site license with ten or more sites on each license and by phase transfer from NYSDOH. Since the commencement of the transfer, system wide our qualified laboratory personnel have been updating and providing standard operating procedures (SOP), performing quality assurance and validation of new tests/devices, providing competency assessments and helping clinical staffs maintain compliance with state and other regulatory agencies.Results (if a Case Study enter NA)After the final phase of the transfer and POCT standardization implementation in 63 clinics, currently the clinical staffs performing POCT, get expeditious training and troubleshooting in more timely manner and the providers get the results of the ordered POCTs much faster and more efficiently and overall the quality metrics get improved markedly, indicated by internal audit team.ConclusionEven though Implementation of the planned POCT standardization was initially challenging due to the vastness and complexity of our multisite ambulatory care network and later confounded by the COVID -19 pandemic effect but eventually, it helped improve patient care delivery significantly and very effectively. Expectedly, our planned transfer implementation provided standardization and ensured improved quality of POC testing across our health system.

International Consortium to Advance Cross-Species Extrapolation of the Effects of Chemicals in Regulatory Toxicology.

International Consortium to Advance Cross-Species Extrapolation of the Effects of Chemicals in Regulatory Toxicology.

Innovation in regulatory approaches for endocrine disrupting chemicals: The journey to risk assessment modernization in Canada

Globally, regulatory authorities grapple with the challenge of assessing the hazards and risks to human and ecosystem health that may result from exposure to chemicals that disrupt the normal functioning of endocrine systems. Rapidly increasing number of chemicals in commerce, coupled with the reliance on traditional, costly animal experiments for hazard characterization - often with limited sensitivity to many important mechanisms of endocrine disruption -, presents ongoing challenges for chemical regulation. The consequence is a limited number of chemicals for which there is sufficient data to assess if there is endocrine toxicity and hence few chemicals with thorough hazard characterization. To address this challenge, regulatory assessment of endocrine disrupting chemicals (EDCs) is benefiting from a revolution in toxicology that focuses on New Approach Methodologies (NAMs) to more rapidly identify, prioritize, and assess the potential risks from exposure to chemicals using novel, more efficient, and more mechanistically driven methodologies and tools. Incorporated into Integrated Approaches to Testing and Assessment (IATA) and guided by conceptual frameworks such as Adverse Outcome Pathways (AOPs), emerging approaches focus initially on molecular interactions between the test chemical and potentially vulnerable biological systems instead of the need for animal toxicity data. These new toxicity testing methods can be complemented with in silico and computational toxicology approaches, including those that predict chemical kinetics. Coupled with exposure data, these will inform risk-based decision-making approaches. Canada is part of a global network collaborating on building confidence in the use of NAMs for regulatory assessment of EDCs. Herein, we review the current approaches to EDC regulation globally (mainly from the perspective of human health), and provide a perspective on how the advances for regulatory testing and assessment can be applied and discuss the promises and challenges faced in adopting these novel approaches to minimize risks due to EDC exposure in Canada, and our world.

Development of an exposure protocol for toxicity test (FEET) for a marine species: the European sea bass (Dicentrarchus labrax).

Regulatory assessment of the effects of chemicals requires the availability of validated tests representing different environments and organisms. In this context, developing new tests is particularly needed for marine species from temperate environments. It is also important to evaluate effects that are generally poorly characterized and seldom included in regulatory tests. In this study, we designed an exposure protocol using European sea bass (Dicentrarchus labrax) larvae. We examined classical toxicological values (LCx) as well as behavioral responses. By comparing different hatching and breeding strategies, we defined the optimal conditions of exposure as non-agitated conditions in 24- or 48-well microplates. Our exposure protocol was then tested with 3,4-dichloroaniline (3,4-DCA), a recommended reference molecule. Based on our results, the 96 h LC50 for 3,4-DCA corresponded to 2.04 mg/L while the 168 h LC50 to 0.79 mg/L. Behavioral analyses showed no effect of 3,4-DCA at low concentration (0.25 mg/L). In conclusion, the present work established the basis for a new test which includes behavioral analysis and shows that the use of sea bass is suitable to early-life stage toxicity tests.

Integration of Epigenetic Mechanisms into Non-Genotoxic Carcinogenicity Hazard Assessment: Focus on DNA Methylation and Histone Modifications.

Epigenetics involves a series of mechanisms that entail histone and DNA covalent modifications and non-coding RNAs, and that collectively contribute to programing cell functions and differentiation. Epigenetic anomalies and DNA mutations are co-drivers of cellular dysfunctions, including carcinogenesis. Alterations of the epigenetic system occur in cancers whether the initial carcinogenic events are from genotoxic (GTxC) or non-genotoxic (NGTxC) carcinogens. NGTxC are not inherently DNA reactive, they do not have a unifying mode of action and as yet there are no regulatory test guidelines addressing mechanisms of NGTxC. To fil this gap, the Test Guideline Programme of the Organisation for Economic Cooperation and Development is developing a framework for an integrated approach for the testing and assessment (IATA) of NGTxC and is considering assays that address key events of cancer hallmarks. Here, with the intent of better understanding the applicability of epigenetic assays in chemical carcinogenicity assessment, we focus on DNA methylation and histone modifications and review: (1) epigenetic mechanisms contributing to carcinogenesis, (2) epigenetic mechanisms altered following exposure to arsenic, nickel, or phenobarbital in order to identify common carcinogen-specific mechanisms, (3) characteristics of a series of epigenetic assay types, and (4) epigenetic assay validation needs in the context of chemical hazard assessment. As a key component of numerous NGTxC mechanisms of action, epigenetic assays included in IATA assay combinations can contribute to improved chemical carcinogen identification for the better protection of public health.