Use In Safety Assessment Research Articles

Lack of genotoxicity potential and safety assessment of 4-(2-hydroxyethyl) morpholine present as an impurity in pharmaceuticals and nutritional supplements

4-(2-Hydroxyethyl) morpholine (HEM) is widely used as a building block of macromolecules in the manufacture of pharmaceuticals and dietary supplements and could remain as an impurity in the finished products. An evaluation of HEM was conducted to identify endpoints that could be used to determine the point-of-departure (POD) for use in assessing the potential risk from exposure to HEM. No oral repeated dose toxicological studies of appropriate duration were found for HEM. Therefore, suitable analogue(s) were identified. Although oral repeated dose studies were available for the analogues, the studies were not of sufficient duration for use in the assignment of a POD for risk evaluation. Accordingly, the Threshold of Toxicological Concern (TTC) approach, which proposes that a de minimis value can be derived to qualitatively assess risk, was considered for HEM. To determine the appropriate TTC approach (genotoxic or non-genotoxic), the genotoxicity of HEM and its analogues were evaluated. The weight of the evidence indicated that HEM, and the appropriate analogues, are not genotoxic. Considering the chemical structure of HEM, the non-genotoxic Cramer class III TTC value of 1.5 μg/kg bw/day was determined to be appropriate for use in safety assessment of HEM as an impurity in products intended for human consumption.

The use of in vitro methods in assessing human health risks associated with short-chain perfluoroalkyl and polyfluoroalkyl substances (PFAS).

Perfluoroalkyl and polyfluoroalkyl substances (PFAS) are a large class of industrial chemicals with a ubiquitous and persistent presence in the environment. Of the thousands of PFAS used by consumers and industry, very few have been thoroughly characterized for potential adverse effects. This is especially true for the novel short-chain (C < 8) alternatives that replaced legacy PFAS. Perfluoroalkyl and polyfluoroalkyl substances have revealed inconsistencies in the toxicokinetics predicted by animal models and empirical findings in humans. To adequately assess the possible health effects of short-chain PFAS, there is a need for robust aggregated data sets on the mechanistic underpinnings and physiochemical properties of these alternatives. Acquiring relevant data on the health effects of short-chain PFAS can be achieved through high-throughput methods supported by in vitro human cell-based models. This review briefly summarizes some of the toxicity data obtained using human cells in vitro, discusses the advantages and limitations of cell-based models, and provides insights on potential solutions to challenges presented with the use of these methods for use in safety assessments.

Systematic Assessment of Exposure Variations on Observed Bioactivity in Zebrafish Chemical Screening.

The embryonic zebrafish is a powerful tool for high-throughput screening of chemicals. While this model has significant potential for use in safety assessments and chemical prioritization, a lack of exposure protocol harmonized across laboratories has limited full model adoption. To assess the potential that exposure protocols alter chemical bioactivity, we screened a set of eight chemicals and one 2D nanomaterial across four different regimens: (1) the current Tanguay laboratory’s standard protocol of dechorionated embryos and static exposure in darkness; (2) exposure with chorion intact; (3) exposure under a 14 h light: 10 h dark cycle; and (4) exposure with daily chemical renewal. The latter three regimens altered the concentrations, resulting in bioactivity of the test agents compared to that observed with the Tanguay laboratory’s standard regimen, though not directionally the same for each chemical. The results of this study indicate that with the exception for the 2D nanomaterial, the screening design did not change the conclusion regarding chemical bioactivity, just the nominal concentrations producing the observed activity. Since the goal of tier one chemical screening often is to differentiate active from non-active chemicals, researchers could consider the trade-offs regarding cost, labor, and sensitivity in their study design without altering hit rates. Taken further, these results suggest that it is reasonably feasible to reach agreement on a standardized exposure regiment, which will promote data sharing without sacrificing data content.

Proteomics reveals the in vitro protein digestibility of seven transmembrane enzymes from the docosahexaenoic acid biosynthesis pathway

The measurement of protein digestibility is one of the key steps in determining the safety of a genetically modified crop that has been traditionally accomplished using antibodies. Membrane proteins are often extremely difficult to express with replicated authentic tertiary structure in heterologous systems. As a result raising antibodies for use in safety assessment may not be feasible. In this study, LC-MS based proteomics was used to characterise seven transmembrane enzymes from the docosahexaenoic acid biosynthetic pathway that had been introduced into canola. The application of a two-stage digestion strategy involving simulated gastric fluid followed by trypsin enabled the measurement of protein digestibility in vitro. Tryptic peptide markers that spanned the length of each desaturase protein were monitored and showed that these proteins were readily degraded (>95% within 5 min) and highlighted regions of the elongase enzymes that showed limited resistance to simulated gastric digestion. Traditional gel-based and Western blotting analysis of ω3-desaturase and Δ6-elongase revealed rapid hydrolysis of the intact proteins within seconds and no fragments (>3 kDa) remained after 60 min, complementing the novel approach described herein. The LC-MS approach was sensitive, selective and did not require the use of purified proteins.

Novel method for analyzing transport parameters in through-diffusion tests

Buffer materials such as bentonite are vital for absorbing radionuclide leakage and retarding migration from radioactive waste canisters. The diffusion coefficient and the retardation factor are the predominant properties controlling the diffusion-reaction process in a buffer material. Diffusion experiments combined with Crank's graphical method are a well-established process for determining asymptotic diffusion coefficients. However, the inaccuracy of the diffusion coefficient that results from the subjective judgement of the late-time linear part of the cumulative concentration data in Crank's graphical method will deteriorate the estimate of the retardation factor. A novel parameter identification process based on an iterative and analytical method (PIPIAM) is proposed here to obtain the diffusion coefficients and porosity of bentonite using concentration data. The results of PIPIAM and the graphical method are compared through an error analysis of concentration. The results show that PIPIAM outperforms the graphical method in terms of the error reduction of the concentration and the uncertainty decrease of the estimated parameters. The proposed method is thus a good alternative for acquiring transport parameters for use in safety assessments of nuclear waste repositories.

The use of human tissue in safety assessment

IntroductionThe safety-related failure of drugs during clinical phases of development is a significant contributor to drug attrition, wasting resources and preventing treatments from reaching patients. A lack of concordance between results from animal models and adverse events in the clinic has been identified as one potential cause of attrition. In vitro models using human tissue or cells have the potential to replace some animal models and improve predictivity to humans. MethodsTo gauge the current use of human tissue models in safety pharmacology and the barriers to greater uptake, an electronic survey of the international safety assessment community was carried out and a Safety Pharmacology Society European Regional Meeting was organised entitled ‘The Use of Human Tissue in Safety Assessment’. ResultsA greater range of human tissue models is in use in safety assessment now than four years ago, although data is still not routinely included in regulatory submissions. The barriers to increased uptake of the models have not changed over that time, with inadequate supply and characterisation of tissue being the most cited blocks. DiscussionSupporting biobanking, the development of new human tissue modelling technology, and raising awareness in the scientific and regulatory communities are key ways in which the barriers to greater uptake of human tissue models can be overcome. The development of infrastructure and legislation in the UK to support the use of post-mortem or surgical discard tissue will allow scientists to locally source tissue for research.

Genotoxicity of styrene oligomers extracted from polystyrene intended for use in contact with food

Here, we conducted in vitro genotoxicity tests to evaluate the genotoxicity of styrene oligomers extracted from polystyrene intended for use in contact with food. Styrene oligomers were extracted with acetone and the extract was subjected to the Ames test (OECD test guideline No. 471) and the in vitro chromosomal aberration test (OECD test guideline No. 473) under good laboratory practice conditions. The concentrations of styrene dimers and trimers in the concentrated extract were 540 and 13,431 ppm, respectively. Extraction with acetone provided markedly higher concentrations of styrene oligomers compared with extraction with 50% ethanol aqueous solution, which is the food simulant currently recommended for use in safety assessments of polystyrene by both the United States Food and Drug Administration and the European Food Safety Authority. And these high concentrations of styrene dimers and trimers were utilized for the evaluation of genotoxicity in vitro. Ames tests using five bacterial tester strains were negative both in the presence or absence of metabolic activation. The in vitro chromosomal aberration test using Chinese hamster lung cells (CHL/IU) was also negative. Together, these results suggest that the risk of the genotoxicity of styrene oligomers that migrate from polystyrene food packaging into food is very low.

The Research of the Stress Test Technology on Bridge Type Grab Ship Unloader

The safety performance of bridge type grab ship unloaders are the main factors in the normal operation of a bulk cargo wharf. This article made a research of the stress test technology on the use of safety assessment on the structure of the bridge type grab ship unloader, through the dynamic stress test of ship unloader key parts of the structure under the use of the condition, analysis bridge type grab ship unloader safety performance is at ordinary times and maintenance and inspection needs to focus on the dangerous site.Stress test shows that the Maximum compressive stress is Point 7, its maximum dynamic compressive stress is 82.5MPa; while the maximum tensile stress occurs at point 11, its maximum dynamic tensile stress of 72.5MPa. After 17 years used, The force main parts (except former trolleys) of the ship unloader are basically the same as its design value.

Considerations Regarding Nonhuman Primate Use in Safety Assessment of Biopharmaceuticals

Selection of a pharmacologically responsive species can represent a major challenge in designing nonclinical safety assessment programs for many biopharmaceuticals (eg, monoclonal antibodies (mAbs)). Frequently, the only relevant species for nonclinical testing of mAbs is the non-human primate (NHP). This situation, coupled with a rapidly increasing number of mAb drugs in development, has resulted in a significant increase in the number of NHPs used in nonclinical safety assessment. Apart from ethical considerations related to responsible animal use, there is a clear need for more efficient and innovative approaches to drug discovery and development; these factors drive the need to investigate alternative approaches and strategies for the safety assessment. This review summarizes important scientific and regulatory perspectives derived from presentations and audience discussions in an educational forum at the 2010 annual American College of Toxicology meeting regarding opportunities for employing alternative approaches to minimize NHP use in mAb drug development.

Influence of creep on water pressure measured from borehole tests in the Meuse/Haute-Marne Callovo-Oxfordian argillites

Porewater pressure is an important parameter for use in safety assessment of underground waste disposal. In order to measure porewater pressure in the Callovo-Oxfordian argillites, ANDRA has performed several in-situ tests, which consist in measuring time evolution of water pressure in an almost closed chamber. This was accomplished using an in-place pressure sensor coupled with an electromagnetic transmission device (called an EPG probe). The measured values show a small hydraulic overpressure (0.1 MPa) compared with the estimated value at the corresponding depth. In the framework of a scientific cooperation agreement between Andra and Ineris, a study was undertaken to examine whether all or a part of this overpressure could be attributed to the hydro-mechanical coupled processes linked with the creep of argillites and the stress relaxation in the experimental measuring chamber-nearby. In the whole, the numerical results were in good agreement with the measured results. Poroviscoplasticity can explain the increasing pressure in the borehole. The measured overpressure can be reached with adequate viscoplastic model parameters.

Pressure solution for sequential hydraulic tests in low‐transmissivity fractured and nonfractured media

In the last decade, considerable effort has been applied to the characterization of low‐permeability, heterogeneous formations. A primary reason for the increased activity is the importance of estimating formation properties for use in safety assessments at proposed nuclear waste disposal sites, such as those in Switzerland, Germany, Sweden, and the United States. Methods for determining formation properties (e.g., transmissivity, static head, storativity, and flow boundaries) are varied, but hydraulic testing is commonly used. Hydraulic tests in low‐permeability media typically consist of a sequence of multiple test events such as slug, constant pressure, and pulse tests. Each single test event can significantly affect the measured pressure response of subsequent test events. The pressure response can also be affected by borehole mud pressures that occur prior to testing (i.e., pretest pressures) and other factors such as well bore storage, well bore skin, and well bore temperature. We present a new analytical solution that accounts for all of the aforementioned complexities. The solution technique treats a sequence of pretest pressures and multiple test events (slugs, pulses, and shut‐ins) as one test sequence, thereby accounting for the influence of one test event upon another. The solution is derived so that only a kernel function, the constant‐rate pumping test solution, is required for new flow models. Furthermore, the solution is presented for any flow dimension allowing for interpretation in fractured formations where linear, radial, and fractional flow may exist. We demonstrate the use of the solution by inverse modeling to estimate the flow model and parameters for an example hydraulic test conducted in Switzerland.

Quantification of the uncertainty in the effect of irradiation on Charpy properties

The provision of material property values for use in safety assessments requires the use of statistical analysis techniques which can produce, for the deterministic approach, best estimate and confidence limit values and, for the full probabilistic method, probability distributions. In this paper a description is given of a robust and efficient method of analysis for deriving probability distributions which reflect the information in the data. As this novel approach adopts a Bayesian viewpoint for the analysis, the main aspects of this will first be presented before moving on to giving the details of the method. In order to illustrate the use of the various methods, results will be presented of an analysis of the effect of neutron irradiation dose on Charpy impact energy curves. On the basis of this analysis a model is derived with which it is possible to predict the form of the Charpy curve at any dose and for any probability level. Comparisons between the model predictions and the measured values are shown.

An Overview of INEL Fusion Safety R&D Facilities

The Fusion Safety Program at the Idaho National Engineering Laboratory has the lead for fusion safety work in the United States. Over the years, we have developed several experimental facilities to provide data for fusion reactor safety analyses. We now have four major experimental facilities that provide data for use in safety assessments. The Steam-Reactivity Measurement System measures hydrogen generation rates and tritium mobilization rates in high-temperature (up to 1200°C) fusion relevant materials exposed to steam. The Volatilization of Activation Product Oxides Reactor Facility provides information on mobilization and transport and chemical reactivity of fusion relevant materials at high temperature (up to 1200°C) in an oxidizing environment (air or steam). The Fusion Aerosol Source Test Facility is a scaled-up version of VAPOR. The ion-implanta-tion/thermal-desorption system is dedicated to research into processes and phenomena associated with the interaction of hydrogen isotopes with fusion materials. In this paper we describe the capabilities of these facilities.

Undrained shear strength for liquefaction flow failure analysis

An important factor in evaluating the stability of hydraulic fills against flow sliding is the undrained steady-state strength mobilized in the field. This paper proposes an empirical relationship between three factors: the undrained strength back-calculated from fills that failed by flow sliding, equivalent clean sand normalized blow-count values, and soil-specific parameters from steady-state laboratory testing. It is shown that Suo, which is a reference value of steady-state strength at maximum void ratio, is an important soil parameter. The proposed method offers an explanation for the performance of many artificial sand islands in the Beaufort Sea, indicates the extreme sensitivity of Suoto soil type and the usefulness of Suofor assessing the potential strength loss of soils for use in safety assessments of existing hydraulic fills. Key words : undrained strength, liquefaction, sand, field, case-histories, analysis.

New approaches to the assessment of eye and skin irritation

Assessment of eye and skin irritation potential is an important part of any comprehensive toxicology programme for new chemicals and consumer products. The original skin and eye irritation assessment methods described by Draize et al. are still widely used for regulatory purposes with only slight modification. These methods have been re-evaluated in the light of the modern approach to toxicological testing requiring refinement of protocols, reduction in animal numbers, and replacement of in vivo tests by in vitro assays. A refinement in the original Draize skin irritation test accepted by regulatory authorities is reduction of test substance exposure time from 24 to 4 h. This makes the test less stressful. The Low Volume Eye Irritation Test is also a less stressful, more predictive refinement of the Draize eye irritation procedure. Many in vitro models are being developed for use in the assessment of eye and skin irritation potential in the hope that the animal tests may some day be replaced. In order for alternative tests to be incorporated into safety assessment, they must undergo a defined evaluation that allows toxicologists to determine whether the new procedures provide relevant information. As the validity of the methods is determined, the new procedures can be incorporated into safety assessment using a tier assessment process. The first step in tier testing is a thorough analysis of existing in-house and published data on the test substance or similar material. A review of physical/chemical characteristics can also provide valuable information. If more data are needed in order to complete the safety assessment, the next step is to evaluate the test substance in in vitro assays. The in vitro data may provide sufficient information to make a safety assessment. If additional information is required, then in vivo testing may be conducted using a limited number of animals or human clinical studies. If alternative procedures are to be ultimately accepted for use in safety assessment, regulatory authorities must become active participants in programmes designed to assess and validate the new tests.

The assessment of impact on nuclear power plant structures in the United Kingdom

Impact research in the United Kingdom has embraced a wide range of topics during the last fifteen years and advice has been provided in the form of guidelines for use in safety assessments and design studies. It is now the intention to produce a comprehensive Impact Assessment Procedure encompassing the definition of loading, whipping pipe effects and the response of steel and concrete targets. This paper is restricted to introducing the methods used for characterising missiles from pressurised vessels and for determining the impact damage produced in concrete targets. Considerable reliance has been placed on the interpretation of experimental data and guidance is therefore limited by the availability of such data. This paper indicates the extent to which advice can be given and the issues which still need further attention. An example is given of the use of the methods for characterising missiles from a cylindrical pressure vessel.

地層処分時のガラス固化体浸出試験 ＥＣラウンドロビンテストの結果

This brief report describes the test results for the repository simulation test which is proposed and organized by the Commissions of European Comunities. There were three options of the test medium; granite, clay and salt, and the leaching experiments of granite option were carried out by 10 different laboratories of 9 countries under contolled temperature of 90°C for up to one year. The simulated waste glass was used together with backfill materials, crushed granite and underground water. The results suggested that the most suitable element to indicate the net dissolution of waste glass was B or Mo. The results also indicated that the statistical error among the 10 laboratories were in the range of 20-60% for B, Mo, Li and Cs.The EC commissions summarized from these results that the test procedure was practically valid and the data would be more appropriate for use in safety assessments.