甲基汞神经毒性检测和评价效应指标--即刻早期基因研究

论述了甲基汞神经毒性研究现状，通过分析即刻早期基因（IEG）在甲基汞神经毒性机制中的作用，得出即刻早期基因能作为甲基汞神经毒性检测和评价的效应指标，同时也简要介绍即刻早期基因的研究方法，并指出利用基因芯片技术能够被步筛选出甲基汞对大鼠脑基因表达影响的相关基因。     

Effects of 2,4-dichlorophenoxyacetic acid formulation on medulla spinalis of Poecilia reticulata: A histopathological study

This study investigated the possible effects of a commonly used foliar herbicide 2,4-dichlorophenoxyacetic acid (2,4-D) formulation on medulla spinalis of lebistes. Fish were exposed to 2,4-D (15, 30, 45 mg L⁻¹), behavioral changes were monitored. Fish were fixed, histopathological examination was carried out on sections taken from the upper parts of the fish body. Histopathology showed increase in neuronal loss, swelling indicating formation of intracellular edema, vacuolization noticed as the formation of vacuoles within or adjacent to cells, deformation in the Nissl granules, pyknosis and gliosis in medulla spinalis. Behavioral changes were decreased general activity, grouping, shortness in breath, sudden rotations and jumping, loss of equilibrium and colour. In conclusion, this commercial formulation of 2,4-D is considerably neurotoxic to lebistes. Fish constitute the last link in the chain of the feeding cycle in aquatic eco-system, number of studies investigating acute and chronic neurotoxicity of various herbicides in fish should be increased.     

The mechanism of delayed neuropathy caused by some organophosphorus esters: Using the understanding to improve safety

Abstract

The mechanism of delayed neurotoxicity of some OP (organophosphorus) esters such as DFP (di‐isopropyl phosphorofluoridate) and TOCP (tri‐o‐cresyl phosphate) involves an initial two‐step process affecting an esterase called NTE (neurotoxic esterase). This understanding permits the assessment of delayed neuropathic potential in terms of a quantitative measurement of inhibition of NTE in tissue taken from dosed hens. Structure/activity relationships have been rationalized and the neurotoxic potential of those OP esters which are direct inhibitors of esterases may now be assessed in vitro. The response of human NTE can usefully be compared with that of hen NTE. Nil delayed neurotoxic potential is associated with carbamate or phosphinate anticholinesterases which may be designed as insecticides.     

Uranium bioaccumulation and biological disorders induced in zebrafish (Danio rerio) after a depleted uranium waterborne exposure

Because of its toxicity and its ubiquity within aquatic compartments, uranium (U) represents a significant hazard to aquatic species such as fish. In a previous study, we investigated some biological responses in zebrafish either exposed to depleted or to enriched U (i.e., to different radiological activities). However, results required further experiments to better understand biological responses. Moreover, we failed to clearly demonstrate a significant relationship between biological effects and U radiological activity. We therefore chose to herein examine U bioaccumulation and induced effects in zebrafish according to a chemical dose-response approach. Results showed that U is highly bioconcentrated in fish, according to a time- and concentration-dependent model. Additionally, hepatic antioxidant defenses, red blood cells DNA integrity and brain acetylcholinesterase activity were found to be significantly altered. Generally, the higher the U concentration, the sooner and/or the greater the effect, suggesting a close relationship between accumulation and effect.     

Studying developmental neurotoxic effects of bisphenol A (BPA) using embryonic stem cells

There is little to no toxicity information regarding thousands of chemicals to which people are exposed daily. In fact, of the 84,000 chemicals listed in the United States Toxic Substances Control Act Inventory, there is limited information available on their effects on neural development (Betts, 2010 and US EPA, 2015). The number of chemicals tested remains low due to the high cost of conducting multi-generational animal studies and the lack of alternative testing methods.     

Assessment of Bisphenol A (BPA) neurotoxicity in vitro with mouse embryonic stem cells

The adverse effects of environmental pollution on our well-being have been intensively studied with many in vitro and in vivo systems. In our group, we focus on stem cell toxicology due to the multitude of embryonic stem cell (ESC) properties which can be exerted in toxicity assays. In fact, ESCs can differentiate in culture to mimic embryonic development in vivo, or specifically to virtually any kind of somatic cells. Here, we used the toxicant Bisphenol A (BPA), a chemical known as a hazard to infants and children, and showed that our stem cell toxicology system was able to efficiently recapitulate most of the toxic effects of BPA previously detected by in vitro system or animal tests. More precisely, we demonstrated that BPA affected the proper specification of germ layers during our in vitro mimicking of the embryonic development, as well as the establishment of neural ectoderm and neural progenitor cells.     

美欧环境内分泌干扰物研究框架

欧美于20世纪90年代开始系统研究环境内分泌干扰物（EDs)，为此成立了专门的工作机构负责EDs研究的规划与协调工作。研究框架包括确认EDs对人类和生态效应的方法，剂量一效应关系模型以及检测环境暴露水平等。研究对环境威胁最大受试物的主要毒理学终点有致癌性，生殖发育毒性，神经毒性和免疫毒性，目前危险评价的新进展是应用定量结构活性关系（QSAR）模型预测化学物的安全性。     

Tetrabromobisphenol A (TBBPA): A controversial environmental pollutant

Tetrabromobisphenol A (TBBPA) is one of the most widely used brominated flame retardants and is extensively used in electronic equipment, furniture, plastics, and textiles. It is frequently detected in water, soil, air, and organisms, including humans, and has raised concerns in the scientific community regarding its potential adverse health effects. Human exposure to TBBPA is mainly via diet, respiration, and skin contact. Various in vivo and in vitro studies based on animal and cell models have demonstrated that TBBPA can induce multifaceted effects in cells and animals, and potentially exert hepatic, renal, neural, cardiac, and reproductive toxicities. Nevertheless, other reports have claimed that TBBPA might be a safe chemical. In this review, we re-evaluated most of the published TBBPA toxicological assessments with the goal of reaching a conclusion about its potential toxicity. We concluded that, although low TBBPA exposure levels and rapid metabolism in humans may signify that TBBPA is a safe chemical for the general population, particular attention should be paid to the potential effects of TBBPA on early developmental stages.