Developmental neurotoxicity: methylmercury and prenatal exposure protection in the context of the Minamata Convention / Neurotoxicidad durante el desarrollo: metilmercurio y protección frente a la exposición prenatal a este contaminante en el contexto del Convenio de Minamata

Mercury is a global pollutant of public environmental health concern due to its long-range atmospheric distribution, environmental distribution, and neurotoxic effects. Following biological methylation, methylmercury (MeHg) can be un-evenly bioaccumulated within aquatic food chains. Fish consumption can be a significant route of human exposure to MeHg. MeHg exposure in the prenatal stage, at relatively low levels, has recently been established as harmful during neurological development, potentially leading to intellectual disability. The Minamata Convention on Mercury is a global agreement, currently under ratification, to protect human health and the environment from anthropogenic emissions and releases of mercury and mercury compounds. The resolution regarding the role of the World Health Organization and ministries of health in the implementation of the Convention includes protection of human health from critical exposures to MeHg. Riverside populations living in areas with artisanal small-scale gold mining, and relying heavily on fish consumption, have been identified as the most vulnerable population in terms of MeHg exposure and developmental neurotoxicity. This article focuses on the proper design and dissemination of fish advisories within the context of implementation of the Convention.

El mercurio es un contaminante global motivo de preocupación en materia de salud pública ambiental como consecuencia de su amplia distribución atmosférica, su distribución ambiental y sus efectos neurotóxicos. Tras su metilación biológica, el metilmercurio (MeHg) se puede bioacumular de manera desigual en las cadenas alimentarias acuáticas. El consumo de pescado puede ser una ruta significativa de exposición humana al MeHg. Recientemente, se ha establecido que la exposición a niveles relativamente bajos de MeHg en la etapa prenatal es perjudicial para el neurodesarrollo, pudiendo ocasionar discapacidad intelectual. El Convenio de Minamata sobre el Mercurio es un acuerdo a escala mundial, actualmente en fase de ratificación, cuyo objeto es proteger la salud humana y el medio ambiente de las emisiones antropogénicas y los vertidos de mercurio y sus compuestos. La resolución referente a la función de la Organización Mundial de la Salud y los ministerios de salud en la aplicación del Convenio incluye la protección de la salud humana de exposiciones importantes al MeHg. Se ha establecido que las poblaciones ribereñas que residen en zonas de extracción artesanal de oro a pequeña escala, y que dependen en gran medida del consumo de pescado, son las más vulnerables en términos de exposición al MeHg y neurotoxicidad durante el desarrollo. Este artículo se centra en el diseño y la difusión adecuados de las recomendaciones relativas al consumo de pescado en el contexto de la aplicación del Convenio.

Mercury Exposure in a Riverside Amazon Population, Brazil: A Study of the Ototoxicity of Methylmercury

Introduction Mercury poisoning causes hearing loss in humans and animals. Acute and long-term exposures produce irreversible peripheral and central auditory system damage, and mercury in its various forms of presentation in the environment is ototoxic. Objective We investigated the otoacoustic emissions responses in a riverside population exposed to environmental mercury by analyzing the inhibitory effect of the medial olivocochlear system (MOCS) on transient otoacoustic emissions (TEOAE). Methods The purpose of the research was to evaluate the entire community independently of variables of sex and age. All of the participants were born and lived in a riverside community. After otolaryngologic evaluation, participants were received tympanometry, evaluation of contralateral acoustic reflexes, pure tone audiometry, and recording of TEOAEs with nonlinear click stimulation. Hair samples were collect to measure mercury levels. Results There was no significant correlation between the inhibitory effect of the MOCS, age, and the level of mercury in the hair. Conclusions The pathophysiological effects of chronic exposure may be subtle and nonspecific and can have a long period of latency; therefore, it will be important to monitor the effects of mercury exposure in the central auditory system of the Amazon population over time. Longitudinal studies should be performed to determine whether the inhibitory effect of the MOCS on otoacoustic emissions can be an evaluation method and diagnostic tool in populations exposed to mercury. .

Mercurio en pescados y su importancia en la salud / Mercury in fish and its importance in health

The contamination of fish with methylmercury (MeHg) could hamper the health promoting properties of fish. Currently, there is strong evidence about the health benefits of seafood consumption. When consumed by the mother before and during pregnancy it improves neurodevelopment of infants and toddlers. Thereafter it reduces the risk of cardiovascular and other chronic diseases. The benefits of fish are mainly due to its content of omega-3 long chain polyunsaturated fatty acids, including eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). Other constituents, such as high biological value proteins, fat-soluble vitamins, minerals and trace elements contribute to the benefits. On the other hand, there is also convincing evidence about the adverse effects of MeHg on neurodevelopment both during gestation and in early childhood. We herein review the effects of mercury on health. Based on international evidence and new data on the mercury content in Chilean fish, we also propose a recommendation for fish consumption for our population.

Effects of chronic mthylmercury chloride exposure on activity of protein kinase C in rat cerebellum during development / 吉林大学学报(医学版)

Objective To study the effects of methylmercury chloride(MMC) on protein kinase C(PKC) activities in rat developing cerebellum.Methods The animals in experimental groups were fed standard rat chow with(0.75 mg) MMC(ExpⅠ),1.5 mg MMC(ExpⅡ) and 3.0 mg MMC(ExpⅢ)respectively for 90 d before gestation to(30 d) post parturition.Cerebella of pups from each group on postnatal days(PND) 3,7,17,21 and 30 were dissected. All the samples were separated into cytosol and membrane subcellular fractions and assayed for PKC activity by the improved method from Takai′s.Results Membrane and cytosolic PKC activities of pups′ cerebella from certain experimental groups were significantly higher than those of corresponding control group,PKC activities of rats from ExpⅡ,ExpⅢ and PND 3,7,14 in ExpⅠwere significantly higher than those in control group((P

Inhibitory effect of methylmercury chloride on rat C6 glioma cells in vitro / 吉林大学学报(医学版)

Objective To study the inhibitory effect of methylmercury chloride(MMC) on rat C6 glioma cells in vitro.Methods The rat C6 glioma cells were cultivated in vitro and divided into control group and MMC-treated group(0.08-10.00 ?mol?L-1 MMC were divided into 8 groups with concentration gradient).MTT assay was performed to evaluate the proliferation inhibitory effect and cytotoxicity effect of MMC with different concentrations on cultured rat C6 glioma cells,and flow cytometry was used to assess the effects of MMC treatment on cell apoptosis and cell cycle in rat C6 glioma cells.Results 1.25,2.50,5.00 and 10.00 ?mol?L-1 MMC could inhibit the proliferation of cultured rat C6 glioma cells in vitro,the viabilities of MMC treated C6 glioma cells were significantly lower than those in control group(P