Risk assessment of bisphenol analogues towards mortality, heart rate and stress-mediated gene expression in cladocerans Moina micrura.

Bisphenol A (BPA) is a well-known endocrine-disrupting compound that causes several toxic effects on human and aquatic organisms. The restriction of BPA in several applications has increased the substituted toxic chemicals such as bisphenol F (BPF) and bisphenol S (BPS). A native tropical freshwater cladoceran, Moina micrura, was used as a bioindicator to assess the adverse effects of bisphenol analogues at molecular, organ, individual and population levels. Bisphenol analogues significantly upregulated the expressions of stress-related genes, which are the haemoglobin and glutathione S-transferase genes, but the sex determination genes such as doublesex and juvenile hormone analogue genes were not significantly different. The results show that bisphenol analogues affect the heart rate and mortality rate of M. micrura. The 48-h lethal concentration (LC50) values based on acute toxicity for BPA, BPF and BPS were 611.6 µg L-1, 632.0 µg L-1 and 819.1 µg L-1, respectively. The order of toxicity based on the LC50 and predictive non-effect concentration values were as follows: BPA > BPF > BPS. Furthermore, the incorporated method combining the responses throughout the organisation levels can comprehensively interpret the toxic effects of bisphenol analogues, thus providing further understanding of the toxicity mechanisms. Moreover, the output of this study produces a comprehensive ecotoxicity assessment, which provides insights for the legislators regarding exposure management and mitigation of bisphenol analogues in riverine ecosystems.

Visual evoked potentials can be reliably recorded using noninvasive epidermal electrodes in the anesthetized rat.

PURPOSE: Visual evoked potentials (VEPs) are a powerful tool to evaluate nervous conduction along the visual pathways, both in humans and in animal models. Traditionally, epidural screw electrodes are used to record VEPs in preclinical research. Here we tested the feasibility in the preclinical setting of the same noninvasive technique used for clinical VEP acquisition, by using epidermal cup electrodes with no surgical procedures. METHODS: Monocular flash VEPs were recorded bilaterally under sevoflurane anesthesia once a week for 6 weeks in 14 dark Agouti rats, 7 with implanted epidural screws and 7 with epidermal 6 mm Ø Ag/AgCl cups. RESULTS: VEP traces obtained with the two techniques were morphologically comparable. There were no significant differences in latency of the main visual component between screw-recorded VEPs (sVEPs) and cup-recorded VEPs (cVEPs). Amplitude values with epidermal cups were significantly lower than those with epidural screws. Both techniques provided latencies and amplitudes which were stable over time. Furthermore, with regard to latency both methods ensured highly repeatable measurements over time, with epidermal cups even providing slightly better results. On the other hand, considering amplitudes, cVEPs and sVEPs provided fairly acceptable repeatability. CONCLUSIONS: Epidermal cup electrodes can provide comparable results to those obtained with the "gold standard" epidural screws, while representing a simpler and less invasive technique to test nervous conduction along the visual pathways in the preclinical setting.

Cross-sectional study protocol to assess the environmental exposure of endocrine disruptive chemicals: bisphenol-A and heavy metals in children.

INTRODUCTION: Endocrine-disruptors are exogenous compounds that interfere with the human biological system. Bisphenol-A and toxic ele-mental mixtures (e.g. As, Pb, Hg, Cd, and U) are major endocrine-disruptive chemicals documented by the USEPA. Globally obesi-ty is a major health problem with increasing fast-food intake among children. The use of food packaging material is rising global-ly, becoming a primary source of chemical migration from food contact materials. MATERIAL AND METHODS: This protocol is a cross-sectional study, and the primary outcome is to assess the various dietary and non-dietary exposure sources of endocrine-disruptive chemicals (bisphenol A and heavy metals) through a questionnaire, and quantification of urinary bisphenol A and heavy metals using LC-MS/MS and ICP-MS, respectively, among children. In this study, anthropometric assess-ment, socio-demographic characteristics, and laboratory investigations will be performed. Exposure pathway assessment will be done using questions about household characteristics, surroundings, food and water sources, physical/dietary habits, and nutri-tional assessment. RESULTS: An exposure pathway model will be developed based on the questions on source, pathway/exposure, and receptor (child), of those exposed to or potentially exposed to the endocrine-disruptive chemicals. CONCLUSIONS: The children who are exposed or potentially exposed to the chemical migration sources need intervention through local bodies, school curriculum, and training programs. Also, methodological points of view implication of regression models and the LASSO approach will be assessed to identify the emerging risk factors of childhood obesity and even reverse causality through multi-pathway exposure sources. The feasibility of the current study outcome can be implicated in developing countries.