Comparative Analysis Of Zebrafish And Planarian Model Systems For Developmental Neurotoxicity Screens Using An 87-Compound Library

There is a clear need to establish and validate new methodologies to more quickly and efficiently screen chemicals for potential toxic effects, particularly on development. The emergence of alternative animal systems for rapid toxicology screens presents valuable opportunities to evaluate how systems complement each other. In this article, we compare a chemical library of 87-compounds in two such systems, developing zebrafish and freshwater planarians, by screening for developmental neurotoxic effects. We show that the systems’ toxicological profiles are complementary to each other, with zebrafish yielding more detailed morphological endpoints and planarians more behavioral endpoints. Overall, zebrafish was more sensitive to this chemical library, yielding 86/87 hits, compared to 50/87 hits in planarians. The difference in sensitivity could not be attributed to molecular weight, Log Kow or the bioconcentration factor. Of the 87 chemicals, 28 had previously been evaluated in mammalian developmental neuro- (DNT), neuro- or developmental toxicity studies. Of the 28, 20 were hits in the planarian, and 27 were hits in zebrafish. Eighteen of the 28 had previously been identified as DNT hits in mammals and were highly associated with activity in zebrafish and planarian behavioral assays in this study. Only 1 chemical (out of 28) was a false negative in both zebrafish and planarian systems. Differences in endpoint coverage and system sensitivity illustrate the value of a dual systems approach to rapidly query a large chemical-bioactivity space and provide weight-of-evidence for prioritization of chemicals for further testing

Developmental toxicity of bisphenol A diglycidyl ether (epoxide resin badge) during the early life cycle of a native amphibian species

Bisphenol A diglycidyl ether (BADGE) is used in packaging materials, in epoxy adhesives, and as an additive for plastics, but it is also a potential industrial wastewater contaminant. The aim of the present study was to evaluate the adverse effects of BADGE on Rhinella arenarum by means of standardized bioassays at embryo–larval development. The results showed that BADGE was more toxic to embryos than to larvae at all exposure times. At acute exposure, lethality rates of embryos exposed to concentrations of 0.0005 mg/L BADGE and greater were significantly higher than rates in the vehicle control, whereas lethality rates of larvae were significantly higher in concentrations of 10 mg/L BADGE and greater. The toxicity then increased significantly, with 96‐h median lethal concentrations (LC50s) of 0.13 mg/L and 6.9 mg/L BADGE for embryos and larvae, respectively. By the end of the chronic period, the 336‐h LC50s were 0.04 mg/L and 2.2 mg/L BADGE for embryos and larvae, respectively. This differential sensitivity was also ascertained by the 24‐h pulse exposure experiments, in which embryos showed a stage‐dependent toxicity, with blastula being the most sensitive stage and S.23 the most resistant. The most important sublethal effects in embryos were cell dissociation and delayed development, whereas the main abnormalities observed in larvae related to neurotoxicity, as scare response to stimuli and narcotic effect.Fil: Hutler Wolkowicz, Ianina Ruth. Universidad Nacional de San Martín. Instituto de Investigación e Ingeniería Ambiental; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Svartz, Gabriela Veronica. Universidad Nacional de San Martín. Instituto de Investigación e Ingeniería Ambiental; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Aronzon, Carolina Mariel. Universidad Nacional de San Martín. Instituto de Investigación e Ingeniería Ambiental; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Perez Coll, Cristina Silvia. Universidad Nacional de San Martín. Instituto de Investigación e Ingeniería Ambiental; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin

An investigation on benefits and future expectation of Industrialised Building System (IBS) implementation in construction practices

Industrialised Building System (IBS) is well known in many developing countries due to the benefits that can be derived from its applications in construction projects. However, the low percentage of IBS usage may be due to lack of awareness and knowledge about IBS among many professionals. There may be factors that contribute to a lack of interest from the client towards IBS. The aim of this study is to improve the application of IBS particularly in private construction projects in Malaysia by determining the benefits and expectation on application of IBS in private construction projects. This study adopts a quantitative method using questionnaires that were sent to 35 construction firms as a sampling frame. Finally, the finding of this study hopefully could assist professional parties in construction industry in providing a better ground knowledge for improving decisions making to achieve the success of IBS construction projects implementation and also this study will achieved the project objectives in terms of predetermined objectives that are mostly within the time, specified budget and standard qualit

Mercury removal in wastewater by iron oxide nanoparticles

Mercury is one of the persistent pollutants in wastewater; it is becoming a severe environmental and public health problem, this is why nowadays its removal is an obligation. Iron oxide nanoparticles are receiving much attention due to their properties, such as: great biocompatibility, ease of separation, high relation of surface-area to volume, surface modifiability, reusability, excellent magnetic properties and relative low cost. In this experiment, Fe3O4 and γ-Fe2O3 nanoparticles were synthesized using iron salts and NaOH as precipitation agents, and Aloe Vera as stabilizing agent; then these nanoparticles were characterized by three different measurements: first, using a Zetasizer Nano ZS for their size estimation, secondly UV-visible spectroscopy which showed the existence of resonance of plasmon at λmax∼360 nm, and lastly by Scanning Electron Microscopy (SEM) to determine nanoparticles form. The results of this characterization showed that the obtained Iron oxides nanoparticles have a narrow size distribution (∼100nm). Mercury removal of 70% approximately was confirmed by atomic absorption spectroscopy measurements

Midazolam Efficacy Against Acute Hydrogen Sulfide-Induced Mortality and Neurotoxicity.

Hydrogen sulfide (H2S) is a colorless, highly neurotoxic gas. It is not only an occupational and environmental hazard but also of concern to the Department of Homeland Security for potential nefarious use. Acute high-dose H2S exposure causes death, while survivors may develop neurological sequelae. Currently, there is no suitable antidote for treatment of acute H2S-induced neurotoxicity. Midazolam (MDZ), an anti-convulsant drug recommended for treatment of nerve agent intoxications, could also be of value in treating acute H2S intoxication. In this study, we tested the hypothesis that MDZ is effective in preventing/treating acute H2S-induced neurotoxicity. This proof-of-concept study had two objectives: to determine whether MDZ prevents/reduces H2S-induced mortality and to test whether MDZ prevents H2S-induced neurological sequelae. MDZ (4 mg/kg) was administered IM in mice, 5 min pre-exposure to a high concentration of H2S at 1000 ppm or 12 min post-exposure to 1000 ppm H2S followed by 30 min of continuous exposure. A separate experiment tested whether MDZ pre-treatment prevented neurological sequelae. Endpoints monitored included assessment of clinical signs, mortality, behavioral changes, and brain histopathological changes. MDZ significantly reduced H2S-induced lethality, seizures, knockdown, and behavioral deficits (p < 0.01). MDZ also significantly prevented H2S-induced neurological sequelae, including weight loss, behavior deficits, neuroinflammation, and histopathologic lesions (p < 0.01). Overall, our findings show that MDZ is a promising drug for reducing H2S-induced acute mortality, neurotoxicity, and neurological sequelae

Workplace stress experienced by contractor in Malaysian construction industry

Work pressure can be experienced by any of the parties and organizations within various sectors. The work pressure issue also can be found in the construction industry, as the orientation and the nature of the job lead toward work pressure, such as organization factors, work demand factors, job roles and challenging work environment. Besides, previous studies have proven that uncontrollable of work pressure also led positively towards accident on a construction site. However, this issue had a lack of support and consensus among the parties itself. Therefore, this study is being carried out to explore the issue work stress in the Malaysian construction industry. The aim of this study is to identify the major contributor and measure work stress level in the Malaysian construction industry. The study was conducted within 78 individuals that involved from G7 class of contractors in Malacca with 74% rate of respond. This research is statistically descriptive orientation and questionnaire is being used as a research instrument. Data were analyzed by using the Statistical Package for the Social Sciences 20.0 software. Based on the results, it showed that work demand is the main factors contributing to the high-pressure jobs. Level of work stress experienced by the respondents is high, but they still have a good job in terms of achievements and satisfaction. Therefore, based on the results, all parties; DOSH, CIDB, contractors and others should take this issue seriously. The parties also need to put effort to handle the issue as its consider as an alternative to reduce the number of accidents in construction sites as well as improving performance of the industry

Strategic aims for improving the regulatory assessment of Developmental Neurotoxicity (DNT) using non-animal methods

Currently, the identification of chemicals that have the potential to induce developmental neurotoxicity (DNT) is based on animal testing, since there are no regulatory accepted alternative methods for this purpose. Since at the regulatory level, systematic testing of DNT is not a standard requirement within the EU legislation of chemical safety assessment, DNT testing is only performed in higher tiered tests triggered based on structure activity relationships or evidence of neurotoxicity in systemic adult studies. However, these triggers are rarely used and in addition do not always serve as reliable indicators of DNT as they are observed in an adult rodent animal. Consequently, to date only a limited amount of chemicals (Grandjean and Landrigan, 2006; Smirnova et al., 2014), mainly pesticides (Bjørling-Poulsen et al., 2008) have been tested under US EPA (OPPTS 870.630) or OECD DNT TG 426. Therefore, there is the pressing need for developing alternative methodologies that can more rapidly and cost-effectively screen large numbers of chemicals for their potential to cause DNT. In this report we propose that in vitro studies could contribute to the identification of potential triggers for DNT evaluation since existing cellular models permit the evaluation of a chemical impact on key neurodevelopmental processes, mimicking different windows of human brain development, especially if human models derived from induced pluripotent stem cells are applied. Furthermore, the battery of currently available DNT alternative test methods anchored to critical neurodevelopmental processes and key events identified in DNT Adverse Outcome Pathways (AOPs) could be applied to generate in vitro data useful for various regulatory purposes. Incorporation of in vitro mechanistic information would increase scientific confidence in decision making, by decreasing uncertainty and leading to refinement of chemical grouping according to biological activity. In this report development of IATA (Integrated Approaches to Testing and Assessment) based on key neurodevelopmental processes and AOP-informed is proposed as a tool for not only speeding up chemical screening, but also providing mechanistic data in support of hazard assessment and in the evaluation of chemical mixtures. Such mechanistically informed IATA for DNT evaluation could be developed integrating various sources of information (e.g., non-testing methods, in vitro approaches, as well as in vivo animal and human data), contributing to screening for prioritization, hazard identification and characterization, and possibly safety assessment of chemicals, speeding up the evaluation of thousands of compounds present in industrial, agricultural and consumer products that lack safety data on DNT potential. It is planned that the data and knowledge generated from such testing will be fed into the development of an OECD guidance document on alternative approaches to DNT testing.JRC.F.3-Chemicals Safety and Alternative Method

Leveraging Epidemiology to Improve Risk Assessment.

The field of environmental public health is at an important crossroad. Our current biomonitoring efforts document widespread exposure to a host of chemicals for which toxicity information is lacking. At the same time, advances in the fields of genomics, proteomics, metabolomics, genetics and epigenetics are yielding volumes of data at a rapid pace. Our ability to detect chemicals in biological and environmental media has far outpaced our ability to interpret their health relevance, and as a result, the environmental risk paradigm, in its current state, is antiquated and ill-equipped to make the best use of these new data. In light of new scientific developments and the pressing need to characterize the public health burdens of chemicals, it is imperative to reinvigorate the use of environmental epidemiology in chemical risk assessment. Two case studies of chemical assessments from the Environmental Protection Agency Integrated Risk Information System database are presented to illustrate opportunities where epidemiologic data could have been used in place of experimental animal data in dose-response assessment, or where different approaches, techniques, or studies could have been employed to better utilize existing epidemiologic evidence. Based on the case studies and what can be learned from recent scientific advances and improved approaches to utilizing human data for dose-response estimation, recommendations are provided for the disciplines of epidemiology and risk assessment for enhancing the role of epidemiologic data in hazard identification and dose-response assessment

New Zealand Guidelines for cyanobacteria in recreational fresh waters: Interim Guidelines

This document is divided into four main sections, plus 14 appendices. Section 1. Introduction provides an overview of the purpose and status of the document as well as advice on who should use it. Section 2. Framework provides a background to the overall guidelines approach, recommendations on agency roles and responsibilities, and information on the condition of use of this document. Section 3. Guidelines describes the recommended three-tier monitoring and action sequence for planktonic and benthic cyanobacteria. Section 4. Sampling provides advice on sampling planktonic and benthic cyanobacteria. The appendices give further background information and include templates for data collection and reporting, including: • background information on known cyanotoxins and their distribution in New Zealand • information on the derivation of guideline values • photographs of typical bloom events • a list of biovolumes for common New Zealand cyanobacteria • templates for field assessments • suggested media releases and warning sign templates. A glossary provides definitions for abbreviations and terms used in these guidelines