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. .

Temporal modulation visual fields, normal aging, Parkinson's disease and methyl-mercury in the James Bay Cree: a feasibility study

We assessed temporal modulation visual field (TMFs) for 91 observers including controls, Parkinson patients and members of the James Bay Cree community of Northern Québec suspected of being chronically exposed to relatively low levels of methyl-mercury. The main goal was to establish the feasibility of using such procedures to rapidly evaluate visual function in a large field study with the James Bay Cree community. The results show clear normal aging effects on TMFs and the pattern of loss differed depending on the flicker rates used. Group data comparisons between the controls and the experimental groups showed significant effects only between the Cree and normal controls in the 40 and 49 year-old age category for the low temporal frequency condition (2 Hz). Examples of individual analysis shows a Cree observer with severe visual field constriction at the 2 Hz condition with a normal visual field at the 16 Hz condition and a reverse pattern was demonstrated for a ParkinsonÆs patient where a visual field constriction was evident only for the 16 Hz condition. The general conclusions are: Such a technique can be used to evaluate the visual consequences of neuropathological disorders and it may lead to dissociation between certain neurotoxic and neurodegenerative effects depending on the parameters used; this technique can be used for a large field study because it is rapid and easily understood and performed by the subjects; the TMF procedure used showed good test-retest correlations; normal aging causes changes in TMF profiles but the changes will show different patterns throughout the visual field depending on the parameters used.

Effects of low-dose exposure of rat fetuses pancreas to methylmercury: morphometric and stereologic studies

El cloruro de metilmercurio (20 mg/kg de peso corporal), cuando fue administrado oralmente a ratas Wistar en el día 10 de la preñez, dio origen a fetos y placentas de menor peso. Hubo muerte y reabsorción fetal, a pesar de no existir malformaciones macroscópicas. Histológicamente, los acinos pancreáticos, aumentados de tamaño, mostraron forma irregular con grandes núcleos picnóticos en los animales tratados. Los núcleos variaron en tamaño y forma. El lumen de los acinos era menor. En el citoplasma, débilmente eosinófilo, se observaron escasos gránulos de secreción. Los ductos eran desorganizados y presentaron núcleos mayores. Los islotes pancreáticos eran inmaduros y menos organizados. Las alteraciones morfológicas fueron analizadas mediante técnicas morfométricas y estereológicas

Morphologic, morphometric and stereologic analysis of palatine mucosa of rat fetuses after methylmercury administration to the dams during pregnancy

El cloruro de metilmercurio, administrado oralmente a ratas wistar en el día 10 de la gestación (20 mg/kg), originó fetos y placentas menores y cordones umbilicales más cortos. Las incidencias de mortalidad y de reabsorciones se encontraron aumentadas. Histológicamente, el epitelio del paladar duro fue más fino, debido a la reducción significativa del espesor de capa espinosa, con células de menor tamaño y más numerosas. Por otro lado, el epitelio del paladar blando no mostró alteraciones del espesor, y las células presentaron las mismas características. Morfométriucamente, el vólumen celular estaba disminuido en los epitelios del paladar duro y blando. La densidad numérica celular fue mayor en los epitelios del paladar blando y duro. No se observaron alteraciones del espesor de la queratina en el epitelio de los dos regiones palatinas.