Determination of methylmercury in urine by direct mercury analyzer / 中华劳动卫生职业病杂志

Objective: To develop asolvent extraction-direct mercury analyzer method for determination of methylmercury in urine. Methods: After the urinehydrolyzesd by hydrobromic acid, methylmercury was extracted by tolueneand reverse-extracted from L-cysteine solution, it was then detectedbydirect mercuryanalyzer. Results: The linear range was 0.2-50.0 μg/L, and the related coefficient was 0.9999. The relative standard deviations (RSD) within the group were 5.04%-6.64%, and the RSD between the group were 5.65%-8.11 %. The average recovery efficiencies were 85.4%-95.5%. The detection limitation was 0.0482 μg/L and the quantification concentrations was 0.1607 μg/L. Conclusion: The method, which has low detection limit, high sensitivity, easy to operate, is stability for the determination of methylmercury in urine.

Mercury species analysis and tissue distribution in rats after continuous administration of Cinnabaris / 中国中药杂志

Cinnabaris is a traditional Chinese medicine(TCM) commonly used for sedation and tranquilization in clinics, and its safety has always been a concern. This study intends to investigate the species and tissue distribution of mercury in rats after continuous administration of Cinnabaris. In the experiment, 30 rats were randomly divided into the control group(equivalent to 0.5% carboxy-methyl cellulose sodium), low-dose Cinnabaris group(0.2 g·kg~(-1)), high-dose Cinnabaris group(2 g·kg~(-1)), pseudogerm-free control group(equivalent to 0.5% sodium carboxymethyl cellulose), and pseudogerm-free Cinnabaris group(2 g·kg~(-1)). They were orally administered for 30 consecutive days. Ultrasound-assisted acid extraction method combined with high performance liquid chromatography and inductively coupled plasma-mass spectrometry(HPLC-ICP-MS) was adopted to determine inorganic mercury [Hg(Ⅱ)], methylmercury(MeHg), and ethylmercury(EtHg) in different tissue, plasma, urine, and feces of rats. The optimal detection conditions and extraction methods were optimized, and the linearity(R~2>0.999 3), precision(RSD<7.0%), and accuracy(spike recoveries ranged from 73.05% to 109.5%) of all the mercury species were satisfied, meeting the requirements of analysis. The results of mercury species detection showed that Hg(Ⅱ) was detected in all the tissue of the five experimental groups, and the main accumulating organs were the intestinal tract, stomach, and kidney. MeHg existed at a low concentration in most tissue, and EtHg was not detected in all groups. In addition, pathological examination results showed that hepatocyte vacuolar degeneration, loose cytoplasm, light staining, and mononuclear cell infiltration were observed in the high-dose Cinnabaris group, low-dose Cinnabaris group, and pseudogerm-free Cinnabaris group, with slightly milder lesions in the low-dose Cinnabaris group. Hydrous degeneration of renal tubular epithelium could be seen in the high-dose Cinnabaris group and pseudogerm-free Cinnabaris group, but there was no significant difference between the other groups and the control group. No abnormal changes were found in the brain tissue of rats in each group. This paper studied the different mercury species and tissue distribution in normal and pseudogerm-free rats after continuous administration of Cinnabaris for 30 days and clarified its effects on the tissue structure of the liver, kidney, and brain, which provided supporting evidence for the safety evaluation of Cinnabaris.

Consequências do Mercúrio na Saúde Humana e no Meio Ambiente / Consequences of Mercury on Health Human and Environment

Uma das coisas mais bonitas em nossa cultura Munduruku e que nos foi passada por nossos ancestrais é de que nós fazemos parte do mundo e o mundo faz parte de cada um de nós. Tudo foi criado a partir da voz mágica de Karusakaibo usando os corpos dos nossos parentes-seres para fazer nascer todos os nossos alimentos, nossos remédios, nossas curas, nossas sabedorias. Em contrapartida, nós temos que nos esforçar para cuidar do mundo que ele nos deixou e no qual ele continua atuando. Enquanto continuarmos cuidando deste mundo, estaremos honrando a criação e o esforço de nossos avós que sempre lutaram com grande força para nos deixar este mundo bonito. O que se quer dizer com este livro é que nós fazemos parte da natureza e que é importante conhecer para entender quem somos e o que somos. A vida do planeta é a nossa própria vida. Devemos conhecer o mundo que a gente vive e cuidar dele, protegê-lo, pois é tão importante para nós a beleza de tudo que se encontra no ambiente e que está ao nosso redor. O valor da vida é primordial. Essa leitura é para nossas crianças, jovens e adultos para que apreciem e aprendam como se relacionar de forma saudável com a natureza, a fim de que se encantem com o passeio pelo mundo em que vivemos. Assim, imaginar como funciona o meio ambiente, a natureza, o seu ecossistema, assimilando o nosso modo de viver e como tudo está relacionado à nossa volta. Procuramos proporcionar uma leitura fácil, utilizando linguagem simples e acessível para que todos possamos entender o ciclo da vida e como nós nos encaixamos nele. Para compreender melhor, será preciso entrar e caminhar através da leitura. Vamos nos conscientizar, imaginar, olhar com uma visão mais humana, quão rico é ter respeito pelo que temos, que é a terra, uma herança de nosso criador Karusakaibo que entregou em nossas mãos um presente valiosíssimo, tão precioso para cuidarmos com muito carinho. Então, cabe a nós preservar o nosso território para que não seja destruído por nossas ações e pelas ações de pessoas que não conseguem entender nosso modo de vida. Somos responsáveis por cuidar, mas também ensinar aos outros que somos partes do mundo e não seus donos. Desejamos que esta leitura possa lhes ensinar a cuidar do mundo cuidando de si mesmos e das pessoas com quem convivem. Este material é a forma de dizermos NÃO à invasão de nossos territórios e NÃO ao uso de agrotóxicos e mercúrio em nosso alimento e em nossas águas. É nosso jeito de dizer SIM ao respeito ao espírito da natureza e ao bem-estar das futuras gerações. Desejamos a todos uma boa leitura e que ela seja capaz de lembrar a cada um de vocês que cada coisa que está na natureza também está dentro de nós; que a natureza é cíclica e que nós também somos; que alterar o ciclo da natureza afeta a nossa própria vida e empobrece nossa cultura porque mexe com nosso alimento, nossas crenças e nosso espírito.

Methylmercury toxic mechanism related to protein degradation and chemokine transcription

Methylmercury is an environmental pollutant that causes neurotoxicity. Recent studies have reported that the ubiquitin-proteasome system is involved in defense against methylmercury toxicity through the degradation of proteins synthesizing the pyruvate. Mitochondrial accumulation of pyruvate can enhance methylmercury toxicity. In addition, methylmercury exposure induces several immune-related chemokines, specifically in the brain, and may cause neurotoxicity. This summary highlights several molecular mechanisms of methylmercury-induced neurotoxicity.

Concentração de mercúrio total em atum enlatado comercializado no município do Rio de Janeiro: risco potencial à saúde? / Concentration of total mercury in canned tuna marketed in the city of Rio de Janeiro

Este estudo determinou o teor total de mercúrio (HgT) em 69 atuns em conserva de 13 marcas comercializadas no sudoeste do Brasil. Todos os valores são reportados em µg.g-1 de peso úmido. O potencial de risco para a saúde foi estimado com base na concentração de mercúrio e consumo médio (175 g / semana) de peixes no Brasil em comparação com ISPT de 1,6 µg.kg-1 (FAO / WHO, 2010). Uma grande variação na concentração de mercúrio em diferentes espécies foi observada. A concentração média de mercúrio foi de 0,256 ± 0,215 µg.g-1 com maior valor de 1,060 µg.g-1 em uma única lata. Em geral, a concentração média foi inferior à legislação de 1,0 µg.g-1 para espécies predadoras (BRASIL, 2014). A ingestão semanal estimada (EIS) variou de 0,2 a 1,7 µg.kg-1. Para as marcas analisadas de consumo de peixe no Brasil, não há ocorrência de risco à saúde humana. No entanto, uma marca foi superior a ISPT de 1,6 µg.kg-1, não mostrando segurança para o grupo de risco específico. Serão necessários mais estudos, incluindo dados específicos sobre o consumo de atum em conserva em populações específicas, bem como o tipo de peixe, tamanho e local de pesca.

Burden of Mild Mental Retardation attributed to prenatal methylmercury exposure in Amazon: local and regional estimates / Carga de Retardo Mental Leve atribuída à exposição pré-natal ao metilmercúrio na Amazônia: estimativas local e regional

Abstract The gold rush in the Amazon Region caused an increase of mercury (Hg) levels in the environment, and, consequently, raised human exposure. Once released into aquatic systems, Hg could generate methylmercury (MeHg), an extremely toxic compound, which is accumulated through trophic chains. Several studies have provided evidences of the brain sensitivity to MeHg, as well as, of the fetus vulnerability during pregnancy. The main objective of this study was to estimate the Mild Mental Retardation (MMR) in Amazonian populations, caused by prenatal exposure to MeHg, using the methodology proposed by Poulin (2008), which quantifies the environmental burden of disease. The estimates of the MMR burden, attributed to prenatal MeHg exposure, were based on the calculation of Disability-Adjusted Life Years (DALY), which were obtained from MMR incidence rate in the studied populations. At the local level, the MMR incidence rate calculations were based on primary data of MeHg exposure of riverine women at childbearing age. The MMR incidence rate was equal to 5.96/1,000 infants, which would result in 2.0 IQ points loss in 34.31% of the newborns. The estimated DALY/1,000 infants was equal to 71.2, while the DALY was 576. For the regional estimates, different exposure scenarios were created. The calculated DALY varied from 3,256 to 65,952 per year.

Resumo A corrida pelo ouro na Amazônia elevou os níveis de mercúrio (Hg) no ambiente e, consequentemente, aumentou a exposição humana. Uma vez liberado em sistemas aquáticos, o Hg pode gerar metilmercúrio (MeHg), um composto tóxico que se acumula ao longo de cadeias tróficas. Vários estudos têm gerado evidências sobre a sensibilidade do cérebro ao MeHg, bem como sobre a vulnerabilidade do feto durante a gravidez. O principal objetivo deste trabalho foi estimar a carga de Retardo Mental Leve (RML) em populações amazônicas, causada pela exposição pré-natal ao MeHg, utilizando a metodologia proposta por Poulin (2008). As estimativas de RML, atribuída à exposição ao MeHg pré-natal, foram baseadas no cálculo dos Anos de Vida Ajustados por Incapacidade (DALY), que foi desenvolvido a partir de taxa de incidência RML nas populações estudadas. Em nível local, o cálculo da taxa de incidência RML baseou-se em dados primários sobre a exposição ao MeHg em mulheres ribeirinhas em idade fértil. A taxa de incidência RML foi igual a 5,96/1.000 nascidos, o que resulta na perda de 2,0 pontos de QI em 34,31% dos nascidos. A estimativa de DALY/1.000 nascidos foi igual a 71,2, enquanto o DALY foi de 576. Para as estimativas regionais, foram criados diferentes cenários de exposição. Os DALYs calculados variaram de 3.256 a 65.952 por ano.

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.

Methylmercury inhibits prolactin release in a cell line of pituitary origin

Heavy metals, such as methylmercury, are key environmental pollutants that easily reach human beings by bioaccumulation through the food chain. Several reports have demonstrated that endocrine organs, and especially the pituitary gland, are potential targets for mercury accumulation; however, the effects on the regulation of hormonal release are unclear. It has been suggested that serum prolactin could represent a biomarker of heavy metal exposure. The aim of this study was to evaluate the effect of methylmercury on prolactin release and the role of the nitrergic system using prolactin secretory cells (the mammosomatotroph cell line, GH3B6). Exposure to methylmercury (0-100 μM) was cytotoxic in a time- and concentration-dependent manner, with an LC50 higher than described for cells of neuronal origin, suggesting GH3B6 cells have a relative resistance. Methylmercury (at exposures as low as 1 μM for 2 h) also decreased prolactin release. Interestingly, inhibition of nitric oxide synthase by N-nitro-L-arginine completely prevented the decrease in prolactin release without acute neurotoxic effects of methylmercury. These data indicate that the decrease in prolactin production occurs via activation of the nitrergic system and is an early effect of methylmercury in cells of pituitary origin.

Primary headaches interfere with the efficacy of temporomandibular disorders management

OBJECTIVES: This cross-sectional study aimed to evaluate the influence of Primary Headache (PH) on efficacy of a Temporomandibular Disorders (TMD) conservative therapy and its association with the presence of self-reported parafunctional habits. SAMPLE AND METHODS: Sample was composed of 400 medical records, divided into four groups: I) Muscular TMD (n=64); II) Muscular TMD+PH (n=48); III) Muscular TMD+Articular TMD (n=173); IV) Muscular TMD+Articular TMD+PH (n=115). All groups had undergone a TMD therapy for three months with a stabilization appliance and counseling for habits and behavioral changes, with no specific headache management. Current pain intensity and existence or not of self-reported bruxism were assessed. Repeated measures ANOVA and Chi-Square test followed by Odds were used for statistical analysis, with a significance level of 5%. RESULTS: results of this study showed that: (1) A conservative therapy with stabilization appliance and counseling for habits and behavioral changes was effective in the TMD pain relief; (2) Groups with an additional diagnosis of PH had worsened the pain improvement significantly; and (3) no association between the presence of self-reported bruxism and PH was found. CONCLUSIONS: this study could elucidate the important effect that headache may have on the TMD management. .

The Benefit Risk Assessment of Consumption of Marine Species Based on Benefit-Risk Analysis for Foods (BRAFO)-tiered Approach / 生物医学与环境科学（英文）

<p><b>OBJECTIVE</b>To assess the net health effect caused by the consumption of specific marine species based on Benefit-Risk Analysis for Foods (BRAFO)-tiered approach.</p><p><b>METHODS</b>Twenty species were collected from the Zhoushan Archipelago, China. Concentrations of n-3 long-chain polyunsaturated fatty acids, methyl mercury (MeHg), and dioxin-like compounds (DLCs) in the samples were analyzed for benefit risk assessment based on BRAFO-tiered approach.</p><p><b>RESULTS</b>Based on the BRAFO-tiered approach, reference scenario (no intake) and alternative scenario (intake of specific species of 200 g/week) were determined. The exposure to MeHg/DLCs via alternative scenario of all studied species did not exceed provisional tolerable weekly/monthly intake. However, the adult population with high DLCs exposure in China would significantly exceed the upper limit of DLCs via an additional alternative scenario of some species such as Auxis thazard. The results of deterministic computation showed that alternative scenario of all studied species generated clear net beneficial effects on death prevention and child IQ gain.</p><p><b>CONCLUSION</b>The alternative scenario of all studied species could be recommended to population with average DLCs exposure, and the reference scenario of species with relatively high DLCs concentration could be recommended to population exposed to high DLCs.</p>

Effect of Zhusha Anshen pill, cinnabar, HgS, HgCl2 and MeHg on gene expression of renal transporters in mice / 中国中药杂志

<p><b>OBJECTIVE</b>To study the effect of Zhusha Anshen pill, cinnabar, HgS, HgCl2 and MeHg on the gene expression of renal transporters in mice.</p><p><b>METHOD</b>Healthy male mice were given equivalent physiological saline, Zhusha Anshen pill (1.8 g · kg(-1), containing 0.17 g · kg(-1) of mercury), cinnabar (0.2 g · kg(-1), containing 1.7 g · kg(-1) of mercury), high dose cinnabar (2 g · kg(-1), containing 1.7 g · kg(-1) of mercury), HgS (0.2 g · kg(-1), containing 0.17 g · kg(-1) of mercury), HgCl2 (0.032 g · kg(-1), containing 0. 024 g · kg(-1) of mercury), MeHg (0.026 g · kg(-1), containing 0.024 g · kg(-1) of mercury), once daily, for 30 d, measuring body mass gain. 30 days later, the mice were sacrificed. The mercury accumulation in kidneys was detected with atomic fluorescence spectrometer. Expressions of Oat1, Oat2, Oat3, Mrp2, Mrp4, Urat1 were detected with RT-PCR.</p><p><b>RESULT</b>Compared with the normal control group, a significant accumulation of Hg in kidney in HgCl2 and MeHg groups was observed (P <0.05), but these changes were not found in other groups. Compared with normal control group, mRNA expressions of Oat1 and Oat2 were evidently lower in HgCl2 and MeHg groups, but mRNA expressions of Mrp2 were apparently higher in HgCl2 group (P <0.05), mRNA expression of Mrp4 was significant higher in HgCl2 and MeHg groups, and mRNA expression of Urat1 was apparently lower in MeHg group.</p><p><b>CONCLUSION</b>HgCl2 and MeHg groups show significant difference from the normal group in mercury accumulation in kidneys and gene expression of kidney transporters, but with no difference between other groups and the normal group. Compared with HgCl2 and MeHg, cinnabar and its compounds could cause lower renal toxicity to mice.</p>

Mercúrio e Metilmercúrio em cabelos de crianças e em peixes mais consumidos em Cubatão, Estado de São Paulo, Brasil / Mercury and Methylmercury in the children hair and fish mostly consumed in Cubatão, São Paulo State, Brazil

This study evaluated Hg and MeHg concentrations in fish muscle and children hair from Cubatão, using asstrategies: i) Hg and MeHg determinations in the mostly consumed fish species, ii) Hg and MeHg determinationsin 93 children hair samples (from 04 to 14 years old), and iii) analysis on the children diet consumptionquestionnaire answered by the respective parents. The results obtained in a similar study in Cananeia were usedas references. These two regions show different environmental anthropogenic impacts and distinct eating habits.The quantity and the frequency of fish consumption were the most important factors of Hg bioaccumulation inchildren hair. In both cities, 95 % of mercury contents in hair were >1 mg.kg-1 (US EPA reference) in analyzedchildren, and MeHg were between 67 and 83 % of total Hg. The median for total Hg concentration in fishmuscle (wet basis) ranged from 10 to 179 μg.kg-1 for Cananéia and 10 to 181 μg.kg-1 for Cubatão, values lowerthan the Brazilian limits for Hg in fish. Considering the Hg contents detected in the mostly consumed fish andhair, they indicate that the children are not at risk for Hg and MeHg contamination...

Este estudo avaliou a concentração de Hg e MeHg em amostras de peixes e de cabelos de crianças de Cubatão, usando-se como estratégia: i) Hg total e MeHg em peixes mais consumidos; ii) Hg total e MeHg em cabelos de 93 crianças (04 a 14 anos); iii) análise do inquérito alimentar respondido pelos pais. Os dados obtidos em estudo similar realizado em Cananéia foram usados como referência. Essas duas regiões estuarinas, sob diferentes graus de impacto ambiental, apresentam diferentes hábitos alimentares. A quantidade e a frequência de consumo de peixes foram os fatores mais importantes na bioacumulação de Hg nos cabelos. Em ambas as cidades, 95 % das concentrações de Hg total nos cabelos foram abaixo de 1 mg.kg-1 (limite US EPA) e o percentual de MeHg ocorreu entre 67 e 83 % em relação ao teor de Hg total. As medianas para Hg total nos músculos (base úmida) variaram de 10 a 179 μg.kg-1 para peixes de Cananéia e 10 a 181 μg.kg-1 de Cubatão, inferiores ao limite da legislação brasileira para Hg. A partir dos teores para Hg total e MeHg em peixes mais consumidos e cabelos, as crianças parecem não estar em risco de contaminação...

Zumbido em uma população ribeirinha exposta ao metilmercúrio / Tinnitus in a riverside population exposed to methyl-mercury

Objetivo : Estudar a prevalência de zumbido, verificando se há associação entre a queixa desse sintoma e o teor de mercúrio e mensurar seu impacto na qualidade de vida. Métodos : Estudo seccional em toda a população do Lago do Puruzinho, localizada na margem esquerda do Rio Madeira, cidade de Humaitá, Estado do Amazonas, Brasil. Todos os residentes maiores de 18 anos, de ambos os gêneros, foram submetidos à anamnese, avaliação otorrinolaringológica e exame audiológico. Os indivíduos que apresentaram queixa de zumbido responderam à versão traduzida do questionário Tinnitus Handicap Inventory (THI). Também foram pesquisados os teores de mercúrio total no cabelo desses indivíduos. Resultados: Para análise dos resultados sobre a queixa de zumbido, os sujeitos foram divididos em dois grupos quanto à presença ou não de zumbido. O Grupo 1 foi composto por indivíduos que apresentaram queixa de zumbido e o Grupo 2, por indivíduos sem zumbido. Foi observado que 40% dos indivíduos apresentaram escores do THI compatíveis com handicap leve. A análise da associação da presença de zumbido com os teores de mercúrio total no cabelo mostrou que ambos os grupos apresentaram níveis elevados de mercúrio, porém não ocorreram diferenças entre os grupos. Conclusão : Um quarto dos ribeirinhos apresentou queixa de zumbido e exposição significativa ao mercúrio, mas não houve associação entre o zumbido e os níveis elevados de mercúrio. .

Purpose : To study the association between the prevalence of tinnitus and mercury exposure and measure the influence of tinnitus on the quality of life. Methods : We conducted a cross-sectional study of men and women aged above 18 years residing in the Lake Puruzinho region, which is located on the left bank of the Rio Madeira, Humaita city, Amazonas state, Brazil. All subjects underwent anamnesis, otorhinolaryngologic evaluation, and an audiology test. Individuals who experienced tinnitus completed the translated Tinnitus Handicap Inventory (THI). We also examined the levels of total mercury in the hair of these individuals. Results : To analyze the results regarding the prevalence of tinnitus, the subjects were divided into two groups according to the presence or absence of tinnitus. Group 1 was composed of subjects with tinnitus and Group 2 was composed of subjects without tinnitus. Consequently, 40% of individuals had scores consistent with mild handicap according to the THI. The analysis of the association between tinnitus and levels of total mercury in hair samples showed that both groups had high levels of mercury. However, this finding was not significantly different between groups. Conclusion : Herein, 25% of the subjects complained of tinnitus and significant exposure to mercury; however, there was no association between the prevalence of tinnitus and high levels of mercury. .

Toxic effects of methylmercury, arsanilic acid and danofloxacin on the differentiation of mouse embryonic stem cells into neural cells

This study was performed to assess the neurotoxic effects of methylmercury, arsanilic acid and danofloxacin by quantification of neural-specific proteins in vitro. Quantitation of the protein markers during 14 days of differentiation indicated that the mouse ESCs were completely differentiated into neural cells by Day 8. The cells were treated with non-cytotoxic concentrations of three chemicals during differentiation. Low levels of exposure to methylmercury decreased the expression of GABAA-R and Nestin during the differentiating stage, and Nestin during the differentiated stage. In contrast, GFAP, Tuj1, and MAP2 expression was affected only by relatively high doses during both stages. Arsanilic acid affected the levels of GABA(A)-R and GFAP during the differentiated stage while the changes of Nestin and Tuj1 were greater during the differentiating stage. For the neural markers (except Nestin) expressed during both stages, danofloxacin affected protein levels at lower concentrations in the differentiated stage than the differentiating stage. Acetylcholinesterase activity was inhibited by relatively low concentrations of methylmercury and arsanilic acid during the differentiating stage while this activity was inhibited only by more than 40 microM of danofloxacin in the differentiated stage. Our results provide useful information about the different toxicities of chemicals and the impact on neural development.

Environmental Mercury and Its Toxic Effects / 예방의학회지

Mercury exists naturally and as a man-made contaminant. The release of processed mercury can lead to a progressive increase in the amount of atmospheric mercury, which enters the atmospheric-soil-water distribution cycles where it can remain in circulation for years. Mercury poisoning is the result of exposure to mercury or mercury compounds resulting in various toxic effects depend on its chemical form and route of exposure. The major route of human exposure to methylmercury (MeHg) is largely through eating contaminated fish, seafood, and wildlife which have been exposed to mercury through ingestion of contaminated lower organisms. MeHg toxicity is associated with nervous system damage in adults and impaired neurological development in infants and children. Ingested mercury may undergo bioaccumulation leading to progressive increases in body burdens. This review addresses the systemic pathophysiology of individual organ systems associated with mercury poisoning. Mercury has profound cellular, cardiovascular, hematological, pulmonary, renal, immunological, neurological, endocrine, reproductive, and embryonic toxicological effects.

Exposição aguda ao Metilmercúrio em ratos em desenvolvimento: mini-revisão / Acute exposition of developing rats to Methylmercury: a mini-review

Mercúrio (Hg) está presente no ambiente em três diferentes formas químicas: elementar (Hg0), inorgânico e orgânico, sendo que a sua distribuição, toxicidade e metabolismo são dependentes de sua forma química. A exposição oral ao consumo de peixes e alimentos contaminados é a principal forma de exposição humana ao metilmercúrio (MeHg), um poluente ambiental que é absorvido por ingestão, inalação e através da pele. O MeHg é um potente neurotóxico, especialmente para o cérebro em desenvolvimento. Neste estudo, foram examinados os principais efeitos da exposição ao MeHg durante o desenvolvimento salientando os mecanismos bioquímicos envolvidos nestes processos. Também foram apresentados recentes resultados sobre o uso de extratos de plantas medicinais que atenuaram os efeitos adversos deste metal. Deste modo, estes dados reforçam a toxicidade do MeHg durante o desenvolvimento e sugerem possíveis caminhos para futuras intervenções terapêuticas.

Mercury (Hg) is present in the environment in three different chemical forms: elemental, inorganic and organic Hg. The distribution, toxicity and metabolism of Hg are linked to its chemical form. The oral exposition following fish and food contaminated is the main route of contamination of humans to the methilmercury (MeHg), an environmental pollutant which is absorbed by ingestion, inhalation and through the skin. MeHg is a strong neurotoxic molecule, especially for the developing brain. In this study, the main effects of the MeHg exposition and the biochemical parameters involved in this process were examined. The results of the use of plant extracts which attenuate the adverse effects of this metal are also presented here. Therefore, these data reinforce the MeHg toxicity during the development and suggest alternative ways for future therapeutic approaches.

Analysis of Methylmercury Concentration in the Blood of Koreans by Using Cold Vapor Atomic Fluorescence Spectrophotometry

BACKGROUND: Methylmercury is an organic form of mercury that is highly toxic to humans. Here, we present and establish a novel method to detect methylmercury concentrations in the blood of Koreans. METHODS: Methylmercury concentration was analyzed with an automated methylmercury analytic system (MERX, Brooks Rand Co., USA) using cold vapor atomic fluorescence spectrophotometry (CVAFS). A variety of biological materials were digested in methanolic potassium hydroxide solution. The analysis method was validated by examination of certified reference material (955c, National Institute of Standard and Technology, USA). We randomly selected 30 Korean adults (age 20 yr or older) to analyze total blood mercury and methylmercury concentrations. RESULTS: The detection limit and methylmercury recovery rate using this method were 0.1 pg/L and, 99.19% (range: 89.33-104.89%), respectively. The mean blood concentration of methylmercury was 4.54+/-2.15 microg/L (N=30). The mean proportion of methylmercury to the total mercury concentration was 78.27% (range: 41.37-98.80%). CONCLUSIONS: This study is the first report to analyze blood methylmercury concentration using CVAFS in Korea. We expect that this method will contribute to the evaluation of mercury exposure and the assessment of the toxicological impact of mercury in future studies.

Fate and Transport of Mercury in Environmental Media and Human Exposure / 예방의학회지

Mercury is emitted to the atmosphere from various natural and anthropogenic sources, and degrades with difficulty in the environment. Mercury exists as various species, mainly elemental (Hg0) and divalent (Hg2+) mercury depending on its oxidation states in air and water. Mercury emitted to the atmosphere can be deposited into aqueous environments by wet and dry depositions, and some can be re-emitted into the atmosphere. The deposited mercury species, mainly Hg2+, can react with various organic compounds in water and sediment by biotic reactions mediated by sulfur-reducing bacteria, and abiotic reactions mediated by sunlight photolysis, resulting in conversion into organic mercury such as methylmercury (MeHg). MeHg can be bioaccumulated through the food web in the ecosystem, finally exposing humans who consume fish. For a better understanding of how humans are exposed to mercury in the environment, this review paper summarizes the mechanisms of emission, fate and transport, speciation chemistry, bioaccumulation, levels of contamination in environmental media, and finally exposure assessment of humans.

Methylmercury Exposure and Health Effects / 예방의학회지

Methylmercury is a hazardous substance that is of interest with regard to environmental health, as inorganic mercury circulating in the general environment is dissolved into freshwater and seawater, condensed through the food chain, ingested by humans, and consequently affects human health. Recently, there has been much interest and discussion regarding the toxicity of methylmercury, the correlation with fish and shellfish intake, and methods of long-term management of the human health effects of methylmercury. What effects chronic exposure to a low concentration of methylmercury has on human health remains controversial. Although the possibility of methylmercury poisoning the heart and blood vessel system, the reproductive system, and the immune system is continuously raised and discussed, and the carcinogenicity of methylmercury is also under discussion, a clear conclusion regarding the human health effects according to exposure level has not yet been drawn. The Joint FAO/WHO Expert Committee on Food Additives proposed to prepare additional fish and shellfish intake recommendations for consumers based on the quantified evaluation of the hazardousness of methylmercury contained in fish and shellfish, methylmercury management in the Korea has not yet caught up with this international trend. Currently, the methylmercury exposure level of Koreans is known to be very high. The starting point of methylmercury exposure management is inorganic mercury in the general environment, but food intake through methylation is the main exposure source. Along with efforts to reduce mercury in the general environment, food intake management should be undertaken to reduce the human exposure to methylmercury in Korea.