Intracellular accumulation and DNA damage caused by methylmercury in glial cells

Conselho Nacional de Desenvolvimento Cientifico e Tecnologico, Grant/Award Number: 307382/2019-2Ministério da Saúde. Secretaria de Vigilância em Saúde. Instituto Evandro Chagas. Programa de Pós Graduação em Epidemiologia e vigilância em Saúde. Ananindeua, PA, Brasil / Ministério da Saúde. Secretaria de Vigilância em Saúde. Instituto Evandro Chagas. Ananindeua, PA, Brasil.Ministério da Saúde. Secretaria de Vigilância em Saúde. Instituto Evandro Chagas. Programa de Pós Graduação em Epidemiologia e vigilância em Saúde. Ananindeua, PA, Brasil / Ministério da Saúde. Secretaria de Vigilância em Saúde. Instituto Evandro Chagas. Ananindeua, PA, Brasil.Universidade Federal do Pará - Campus de Altamira. Faculdade de Medicina. Altamira, PA, Brazil.Ministério da Saúde. Secretaria de Vigilância em Saúde. Instituto Evandro Chagas. Ananindeua, PA, Brasil.Ministério da Saúde. Secretaria de Vigilância em Saúde. Instituto Evandro Chagas. Ananindeua, PA, Brasil / Universidade Federal do Pará. Faculdade de Ciências Naturais. Belém, PA, Brazil.Mercury is widely used in industrial and extractive processes, and the improper disposal of waste or products containing this metal produces a significant impact on ecosystems, causing adverse effects on living organisms, including humans. Exposure to methylmercury, a highly toxic organic compound, causes important neurological and developmental impairments. Recently, the genotoxicity of mercurial compounds has gained prominence as one of the possible mechanisms associated with the neurological effects of mercury, mostly by disturbing the mitotic spindle and causing chromosome loss. In this sense, it is important to investigate if these compounds can also cause direct damage to DNA, such as single and double-strand breaks. Thus, the aim of this study was to investigate the cytotoxic and genotoxic potential of methylmercury in cell lines derived from neurons (B103) and glia (C6), exposed to methylmercury (MeHg) for 24 h, by analyzing cell viability, metabolic activity, and damage to DNA and chromosomes. We found that in comparison to the neuronal cell line, glial cells showed higher tolerance to MeHg, and therefore a higher LC50 and consequent higher intracellular accumulation of Hg, which led to the occurrence of several genotoxic effects, as evidenced by the presence of micronuclei, bridges, sprouts, and chromosomal aberration

Trayectoria de la rubéola en el Estado de Pará, Brasil: rumbo a la erradicación

Ministério da Saúde. Secretaria de Vigilância em Saúde. Instituto Evandro Chagas. Ananindeua, PA, Brasil.Ministério da Saúde. Secretaria de Vigilância em Saúde. Instituto Evandro Chagas. Ananindeua, PA, Brasil.Ministério da Saúde. Secretaria de Vigilância em Saúde. Instituto Evandro Chagas. Ananindeua, PA, Brasil.Ministério da Saúde. Secretaria de Vigilância em Saúde. Instituto Evandro Chagas. Ananindeua, PA, Brasil.Ministério da Saúde. Secretaria de Vigilância em Saúde. Instituto Evandro Chagas. Ananindeua, PA, Brasil.Objetivo: Descrever a trajetória da rubéola a partir do perfil soroepidemiológico de indivíduos referenciados ao Instituto Evandro Chagas (IEC) no período de 1989 a 2012, e comparar os resultados antes e após a introdução da vacina contra a rubéola no Estado do Pará, Brasil, pelo programa nacional de imunizações. Metodologia: Estudo retrospectivo com análise de resultados dos testes de dosagem de anticorpos IgG e IgM ao vírus da rubéola pelo método de ELISA em 50.439 indivíduos de diferentes faixas etárias, encaminhados ao IEC para investigação diagnóstica de doenças exantemáticas, nos períodos de 1989-1999 (antes da vacina) e 2000-2012 (após a vacina). Resultados: A prevalência da rubéola no estudo mostrou declínio significativo da infecção de 17,26% para 2,23% após o período vacinal; a frequência da imunidade aumentou de 48,30% para 79,39%; a suscetibilidade declinou de 34,54% para 18,38%. Gestantes infectadas: 9,3% no período anterior à vacinação e 0,6% após o período vacinal. Foram registrados 37 casos de síndrome da rubéola congênita (SRC) no período anterior à vacinação, e 11 casos após a vacinação. De 2010 a 2012 não foram registrados casos autóctones da doença e nem de SRC. Conclusão: O fortalecimento da vigilância epidemiológica, a capacitação de profissionais da área da saúde nos planos de erradicação com o serviço de sentinela, e as estratégias de campanhas de vacinação, com a introdução da vacina contra a rubéola no esquema de rotina, tiveram significativo impacto na redução dos casos de rubéola e SRC, contribuindo para a erradicação.Objective: To describe the rubella trajectory using seroepidemiological profile of individuals referred to Instituto Evandro Chagas (IEC) between 1989 and 2012, and to compare the results before and after rubella vaccine introduction in Pará State, Brazil, through the National Immunization Program. Methods: Retrospective study analyzing the results of tests for detection of IgG and IgM antibodies to rubella virus by ELISA method in 50,439 individuals from different age groups, who were directed to IEC for diagnosis of exanthematous diseases in 1989-1999 (before the vaccine), and 2000-2012 (after the vaccine). Results: The rubella prevalence in this study presented a relevant decrease in infection from 17.26% to 2.23% after the vaccination period; immunity frequency increased from 48.30% to 79.39%; susceptibility was reduced from 34.54% to 18.38%. Infected pregnant women were 9.3% before the vaccination period and 0.6% after the vaccination period. A total of 37 cases of congenital rubella syndrome (CRS) were recorded in the prevaccination period, and 11 after it. From 2010 to 2012, there were no records of autochthonous cases of either that disease or CRS. Conclusion: Strengthening of epidemiological surveillance, training for health professionals in eradication plans with monitoring services, and vaccination strategies with the introduction of rubella vaccine in the routine schedule had a great impact on reducing rubella and CRS cases, contributing to eradication

Meningiomas: An Overview of the Landscape of Copy Number Alterations in Samples from an Admixed Population

Meningiomas are considered the most common intracranial tumors, affecting mainly women. Studies in mixed populations can be of great importance to clarify issues related to the genetic diversity of tumors and their development. Considering that data obtained from analyses of the profile of copy number alterations (CNA) have been a useful diagnostic indicator for many types of tumors and that meningiomas show a complex pattern of gains and losses in the number of copies, our objective was to analyze the CNA profile in 33 samples of meningiomas of different histological grades (WHO Grade I-III) from patients in a city located in the Amazon region of Brazil, using aCGH. We found that the female to male ratio was 3 : 1. The aCGH analysis revealed a total of 2304 CNA, with an average of 69.8 ± 57.4 per case, of which 1197 were gains (52%), 926 were losses (40.2%), 105 were amplifications (4. 5%), and 76 were deletions (3.3%). A significant relationship was observed between the type of CNA and the degree of the tumor (chi-square test: χ2 = 65,844; p<0.0001; contingency coefficient: C = 0.1772; p<0.0001). Evaluating the recurrent changes in at least 50% of the samples, we observe as the most frequent losses of the segments 22q13.1-q13.2 (82%), 1p35.3 (76%), and 14q13.1-q13.2 (67%), involving all histopathological grades. The analysis of these regions showed the inclusion of genes with functions such as regulation, maintenance of cell survival, reorganization of the cytoskeleton, cell signaling, and DNA repair, among others. However, overall, the profiles observed in meningiomas of this admixed population were very similar to the ones observed in Caucasian groups. An interesting finding was a recurrent gain of 8p22 observed only in grade I meningiomas, a region which includes DLC1, a suppressor candidate gene probably implicated in the developments or progression of meningiomas, usually found deleted, when related to CNAs

Seroepidemiological study of measles in populations living in the metropolitan region of Belém, Pará State, Brazil, 2016 to 2018

Instituto Evandro Chagas/SVS/MSMinistério da Saúde. Secretaria de Vigilância em Saúde. Instituto Evandro Chagas. Ananindeua, PA, Brasil.Ministério da Saúde. Secretaria de Vigilância em Saúde. Instituto Evandro Chagas. Ananindeua, PA, Brasil.Ministério da Saúde. Secretaria de Vigilância em Saúde. Instituto Evandro Chagas. Ananindeua, PA, Brasil.Ministério da Saúde. Secretaria de Vigilância em Saúde. Instituto Evandro Chagas. Ananindeua, PA, Brasil.Ministério da Saúde. Secretaria de Vigilância em Saúde. Instituto Evandro Chagas. Ananindeua, PA, Brasil.Ministério da Saúde. Secretaria de Vigilância em Saúde. Instituto Evandro Chagas. Ananindeua, PA, Brasil.Ministério da Saúde. Secretaria de Vigilância em Saúde. Instituto Evandro Chagas. Ananindeua, PA, Brasil.Ministério da Saúde. Secretaria de Vigilância em Saúde. Instituto Evandro Chagas. Ananindeua, PA, Brasil.OBJETIVO: Investigar a soroprevalência de anticorpos contra o sarampo em adultos jovens, residentes em Belém e Ananindeua, estado do Pará, Brasil, visando identificar indivíduos suscetíveis. MATERIAIS E MÉTODOS: Estudo transversal, por conglomerado, de 2.220 indivíduos, sendo 1.109 de Belém e 1.111 de Ananindeua, da faixa etária de 15–39 anos, procedentes de escolas, faculdades, universidades, instituto de pesquisa e quartéis. Dados dos participantes foram coletados mediante questionário epidemiológico e digitados utilizando o software Epi-Info™ v7.0. O teste binomial foi utilizado para a análise de duas proporções por meio do programa BioEstat v5.3, nível de significância p < 0,05. RESULTADOS: A suscetibilidade geral para o sarampo foi de 17,2%, sendo 16,4% em Belém e 18,0% em Ananindeua, maior no sexo masculino, com ampla distribuição geográfica. Foi significativa a diferença na soropositividade em relação aos tipos de vacina recebida, tendo a vacina tríplice viral (SCR) os maiores percentuais, assim como a comparação das informações entre autorreferidos e comprovados por vacinação. Quanto ao número de doses, não houve significância na soropositividade entre os que referiram uma dose em relação a três doses da vacina contra o sarampo. Foi detectado um declínio dos níveis de anticorpos ao longo do tempo (20 anos) após a última vacinação. CONCLUSÃO: Existem grupos de suscetíveis formando bolsões de vulneráveis em ambos os munícipios, assinalando a necessidade do fortalecimento da vigilância epidemiológica e de estratégias de vacinação, diante da reintrodução do vírus, para o controle da doença no Brasil

Is Low Non-Lethal Concentration of Methylmercury Really Safe? A Report on Genotoxicity with Delayed Cell Proliferation.

Human exposure to relatively low levels of methylmercury is worrying, especially in terms of its genotoxicity. It is currently unknown as to whether exposure to low levels of mercury (below established limits) is safe. Genotoxicity was already shown in lymphocytes, but studies with cells of the CNS (as the main target organ) are scarce. Moreover, disturbances in the cell cycle and cellular proliferation have previously been observed in neuronal cells, but no data are presently available for glial cells. Interestingly, cells of glial origin accumulate higher concentrations of methylmercury than those of neuronal origin. Thus, the aim of this work was to analyze the possible genotoxicity and alterations in the cell cycle and cell proliferation of a glioma cell line (C6) exposed to a low, non-lethal and non-apoptotic methylmercury concentration. Biochemical (mitochondrial activity) and morphological (integrity of the membrane) assessments confirmed the absence of cell death after exposure to 3 μM methylmercury for 24 hours. Even without promoting cell death, this treatment significantly increased genotoxicity markers (DNA fragmentation, micronuclei, nucleoplasmic bridges and nuclear buds). Changes in the cell cycle profile (increased mitotic index and cell populations in the S and G2/M phases) were observed, suggesting arrest of the cycle. This delay in the cycle was followed, 24 hours after methylmercury withdrawal, by a decrease number of viable cells, reduced cellular confluence and increased doubling time of the culture. Our work demonstrates that exposure to a low sublethal concentration of MeHg considered relatively safe according to current limits promotes genotoxicity and disturbances in the proliferation of cells of glial origin with sustained consequences after methylmercury withdrawal. This fact becomes especially important, since this cellular type accumulates more methylmercury than neurons and displays a vital role protecting the CNS, especially in chronic intoxication with this heavy metal

Epidemiología molecular del rotavirus aviario en heces de pollos de corte en la Región Amazónica, Brasil, de agosto de 2008 a mayo de 2011

This study was partially supported by a grant from the Science and Technology Secretariat of Pará State, contract n° 067/2008 (Sedect/Fapespa/PA), and Instituto Evandro Chagas/SVS/MS, Brazil. Delana Andreza Melo Bezerra and Jane Haruko Lima Kaiano received a Grant fellowship from the Brazilian National Council for the Development of Science and Technology (CNPq).Ministério da Agricultura, Pecuária e Abastecimento. Laboratório Nacional Agropecuário. Belém, PA, Brasil.Ministério da Saúde. Secretaria de Vigilância em Saúde. Instituto Evandro Chagas. Ananindeua, PA, Brasil.Ministério da Saúde. Secretaria de Vigilância em Saúde. Instituto Evandro Chagas. Ananindeua, PA, Brasil.Universidade Federal Rural da Amazônia. Instituto de Saúde e Produção Animal. Belém, PA, Brasil.Ministério da Saúde. Secretaria de Vigilância em Saúde. Instituto Evandro Chagas. Ananindeua, PA, Brasil.Ministério da Saúde. Secretaria de Vigilância em Saúde. Instituto Evandro Chagas. Ananindeua, PA, Brasil.Ministério da Saúde. Secretaria de Vigilância em Saúde. Instituto Evandro Chagas. Ananindeua, PA, Brasil.Ministério da Agricultura, Pecuária e Abastecimento. Laboratório Nacional Agropecuário. Belém, PA, Brasil.Universidade Federal do Pará. Instituto de Ciências Biológicas. Belém, PA, Brasil.Universidade Estadual de Londrina. Departamento de Medicina Veterinária Preventiva. Londrina, PR, Brasil.Ministério da Saúde. Secretaria de Vigilância em Saúde. Instituto Evandro Chagas. Ananindeua, PA, Brasil.Enteric viruses cause avian diseases that result in economic losses. Avian Rotavirus (AvRV) is the most important virus associated with enteritis in poultry. The main goals of this study were to determine the prevalence of AvRV using molecular tests in broiler chickens (Gallus gallus) from the metropolitan mesoregion of Belém (Pará State, Brazil), to provide epidemiological information, and to compare the rotaviruses detected in this study with reference to strains by phylogenetic analysis. Pooled fecal samples were collected from 37 poultry farms. The samples were tested for the NSP4 gene using reverse transcription polymerase chain reaction (RT-PCR). In total, 35 (41.2%) of the 85 fecal samples were positive for NSP4. There were 19 (51.4%) farms with at least one poultry house positive for AvRV. Considering the distribution of positive samples by age, the chicks aged 31-45 days comprised 18 (51.4%) of the 35 rotavirus-positive samples. Analyzing the data by density population, the houses with more than 9 birds/m2 had 25 (86.2%) positive samples, showing that higher infection rates occurred in higher density houses. To confirm the RT-PCR results and perform phylogenetic analysis, 20 positive samples were selected for sequencing. The rotaviruses detected in our study were clustered in a single group and had 93.5 to 100% sequence identity at the nucleotide level. The most affected age group included broiler chickens older than 15 days. Climatic conditions and high population densities favored the spread of AvRV and supported its uniform maintenance between seasons.As viroses entéricas causam doenças em aves que resultam em perdas econômicas. O rotavírus aviário (AvRV) é o vírus mais importante associado à enterite em aves domésticas. Os principais objetivos deste estudo foram determinar a prevalência do AvRV, usando testes moleculares em frangos de corte (Gallus gallus) da mesorregião metropolitana de Belém (Estado do Pará, Brasil), fornecer informações epidemiológicas e comparar os rotavírus detectados com as cepas através da análise filogenética. Amostras fecais foram coletadas em 37 aviários e foram testadas para o gene NSP4 usando a reação em cadeia da polimerase via transcrição reversa (RT-PCR). No total, das 85 amostras fecais, 35 (41,2%) mostram-se positivas para NSP4. Foram encontrados 19 (51,4%) aviários com pelo menos um galpão positivo para AvRV. Considerando a distribuição de amostras positivas por idade, os frangos de 31-45 dias continham 18 (51,4%) das 35 amostras positivas para rotavírus. Analisando os dados pela densidade populacional, os galpões com mais de 9 aves/m² tiveram 25 (86,2%) amostras positivas, mostrando que índices maiores de infecção ocorreram em galpões de maior densidade. Para confirmar os resultado da RT-PCR e realizar a análise filogenética, 20 amostras positivas foram selecionadas por sequência. Os rotavírus detectados em nosso estudo foram reunidos em um único grupo e tiveram 93,5 a 100% de identidade sequencial no nível de nucleotídeos. O grupo etário mais atingido incluiu frangos de corte com mais de 15 dias. As condições climáticas e a alta densidade populacional favoreceram a disseminação do AvRV e sua manutenção uniforme entre as estações

Chronic intoxication by methylmercury leads to oxidative damage and cell death in salivary glands of rats

Federal University of Pará. Institute of Biological Sciences. Laboratory of Functional and Structural Biology. Belém, PA, Brazil.Federal University of Pará. Institute of Biological Sciences. Laboratory of Functional and Structural Biology. Belém, PA, Brazil.Federal University of Pará. Institute of Biological Sciences. Laboratory of Functional and Structural Biology. Belém, PA, Brazil.Federal University of Pará. Institute of Biological Sciences. Laboratory of Functional and Structural Biology. Belém, PA, Brazil.Federal University of Pará. Institute of Biological Sciences. Laboratory of Functional and Structural Biology. Belém, PA, Brazil.Federal University of Pará. Institute of Biological Sciences. Laboratory of Molecular Pharmacology. Belém, PA, Brazil.Federal University of Pará. Institute of Biological Sciences. Laboratory of Functional and Structural Biology. Belém, PA, Brazil.Ministério da Saúde. Secretaria de Vigilância em Saúde. Instituto Evandro Chagas. Laboratório de Cultura de Tecidos e Citogenética. Ananindeua, PA, Brasil.Ministério da Saúde. Secretaria de Vigilância em Saúde. Instituto Evandro Chagas. Laboratório de Cultura de Tecidos e Citogenética. Ananindeua, PA, Brasil / Federal University of Pará. Institute of Natural Sciences. College of Natural Sciences. Belém, PA, Brazil.Federal University of Pará. Institute of Biological Sciences. Laboratory of Molecular Pharmacology. Belém, PA, Brazil.Federal University of Pará. Institute of Biological Sciences. Laboratory of Functional and Structural Biology. Belém, PA, Brazil.Methylmercury (MeHg) is one of the most toxic species of mercury, causing several systemic damages; however, its effect on the salivary glands has rarely been explored to date. This study was aimed at analyzing the mercury deposit, oxidative stress markers, and cell viability in parotid and submandibular rat salivary glands after chronic methylmercury intoxication. Herein, forty male Wistar rats (40 days old) were used in the experiment. The animals of the experimental group were intoxicated by intragastric gavage with MeHg at a dose of 0.04 mg per kg body weight per day for 35 days, whereas the control group received only corn oil, a diluent. After the period of intoxication, the glands were obtained for evaluation of total mercury deposit, cell viability, and the malondialdehyde (MDA) and the nitrite levels. Our results indicated mercury deposits in salivary glands, with a decrease in cell viability, higher levels of MDA in both glands of intoxicated animals, and a higher concentration of nitrite only in the submandibular gland of the mercury group. Thus, the intoxication by MeHg was able to generate deposits and oxidative stress in salivary glands that resulted in a decrease in cell viability in both types of glands

Cell survival after exposure to methylmercury (MeHg) for 24h.

<p>Cellular viability of cells intoxicated with increased concentrations (panel A) and number of viable and non-viable cells in control and cells exposed to 3 μM (panel B). Insets show micrographs (40X and 100X). Data are expressed as mean ± SEM (n = 4–9). One-way ANOVA followed by <i>post-hoc</i> Tukey test (panel A) and Student’s t-test between control and MeHg groups (panel B) were performed. *P < 0.01 <i>vs</i> all groups.</p

Cell proliferation after exposure to methylmercury (MeHg) 3 μM for 24h.

<p>Cellular viability was evaluated at the beginning (day 0) and the end (day 1) of exposure and after 24h (day 2) and 48h (day 3) of MeHg withdrawal (panel A). Number of viable cells were registered on day 2 (panel B). Micrographs (40X) of culture confluence at days 0, 1 and 2 are shown (panel C). Data are shown as mean ± SEM (n = 3–9). Student’s t-test between control and MeHg groups of the same day was performed. *P < 0.01 <i>vs</i> control group of the same day.</p