1,615 research outputs found

    Heavy Metals and Human Health

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    The Role of Cytometry for Male Fertility Assessment in Toxicology

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    Infertility is nowadays a major concern, affecting approximately 8–12% of the couples and the male factor accounts for about 50% of the cases. Occupational and/or environmental exposure to heavy metals and other pollutants is the main cause of male infertility. Lead, cadmium and chromium are heavy metals widely used in industry and quite persistent in the environment, raising major concerns over the possible effects on the reproductive health of workers and the general population. Sperm DNA integrity is essential for the accurate transmission of paternal genetic information, and normal sperm chromatin structure is important for sperm fertilizing ability. Flow cytometry can be to characterize multiple physical characteristics of the population of spermatozoa in the sperm, including sperm concentration, viability, mitochondrial mass and function, acrosome integrity, capacitation, membrane fluidity, DNA content and status, etc. This chapter elucidates the role of cytometry in the study of male fertility under toxicological insult by pollutants such as chromium, cadmium and lead. Some representative examples are presented using in vivo studies with rodents. In addition, complementary techniques to cytometry and future perspectives will be mentioned in an interdisciplinary point of view to gain knowledge on this subject

    World Press Photo 2012: the discursive construction of the Arab Spring

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    O presente artigo pretende analisar a forma como o fenómeno da Primavera Árabe foi retratado nas fotografias vencedoras do concurso World Press Photo em 2012. As fotografias jornalísticas, embora se apresentem como índices do real, condicionam frequentemente a percepção dos indivíduos e influenciam as suas práticas sociais. Também as fotografias vencedoras do World Press Photo, um dos concursos mais prestigiados de fotojornalismo, em 2012 não fogem ao construtivismo discursivo que molda a representação e a percepção dos acontecimentos. A partir da análise crítica do discurso, nomeadamente dos instrumentos teóricos da semiótica barthesiana e da semiótica social de Gunther Kress e Theo van Leeuwen, procurámos interpretar as 38 fotografias vencedoras do World Press Photo 2012, a fim de reflectirmos sobre o modo como contribuíram para a compreensão da Revolta Árabe e como despertaram o nosso interesse e a nossa imaginação para o desenrolar do conflito.ABSTRACT:This article aims to analyze how the Arab Spring phenomenon was represented in the award-winning photographs of the World Press Photo contest in 2012. Although news photographs are usually seen as indexes of the real, they often limit the perception of individuals and influence their social practices. Also the winning photographs in 2012 of the World Press Photo, one of the most prestigious photojournalism contests, do not escape the discursive constructivism that shapes the representation and perception of events. Drawing from critical discourse analysis, namely from the theoretical tools of barthesian semiotics and Gunther Kress’s and Theo van Leeuwen’s social semiotics, we sought to interpret the 38 award-winning photographs of the World Press Photo contest in 2012, in order to reflect on the way they have contributed to our understanding of the Arab Revolt and aroused our interest and imagination to the unfolding of the conflict.info:eu-repo/semantics/publishedVersio

    The Second Transmembrane Domain of P2X7 Contributes to Dilated Pore Formation

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    Activation of the purinergic receptor P2X7 leads to the cellular permeability of low molecular weight cations. To determine which domains of P2X7 are necessary for this permeability, we exchanged either the C-terminus or portions of the second transmembrane domain (TM2) with those in P2X1 or P2X4. Replacement of the C-terminus of P2X7 with either P2X1 or P2X4 prevented surface expression of the chimeric receptor. Similarly, chimeric P2X7 containing TM2 from P2X1 or P2X4 had reduced surface expression and no permeability to cationic dyes. Exchanging the N-terminal 10 residues or C-terminal 14 residues of the P2X7 TM2 with the corresponding region of P2X1 TM2 partially restored surface expression and limited pore permeability. To further probe TM2 structure, we replaced single residues in P2X7 TM2 with those in P2X1 or P2X4. We identified multiple substitutions that drastically changed pore permeability without altering surface expression. Three substitutions (Q332P, Y336T, and Y343L) individually reduced pore formation as indicated by decreased dye uptake and also reduced membrane blebbing in response to ATP exposure. Three others substitutions, V335T, S342G, and S342A each enhanced dye uptake, membrane blebbing and cell death. Our results demonstrate a critical role for the TM2 domain of P2X7 in receptor function, and provide a structural basis for differences between purinergic receptors. © 2013 Sun et al

    Quantificação do teor de metais em águas engarrafadas comercializadas no município de Belém através de espectrometria de emissão ótica / Quantification of metal content in bottled waters commercialized in the municipality of Belém through spectrometry of optical emission

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    Nos últimos anos tem sido verificado um crescimento considerável no consumo de águas engarrafadas no Brasil, aumentando de 0,3 para 18,5 L per capita/ano. Para atender essa demanda, as indústrias aumentaram a produção, novas empresas surgiram e, consequentemente, surge a necessidade do monitoramento da qualidade dessas águas no mercado. O objetivo deste trabalho foi a quantificação do teor de metais em águas engarrafadas, de cinco marcas comercializadas em supermercados na cidade de Belém-PA. Foram utilizadas 120 (cento e vinte) amostras provenientes de oito locais da cidade. A determinação de metais foi feita utilizando um ICP-OES modelo VISTA PRO.  Os resultados obtidos foram comparados com os valores máximos permitidos (VMP) de acordo com a Portaria de Consolidação N°5/17 do Ministério da Saúde. Os teores médios de Al, Fe, Na e Ba estiveram abaixo do máximo permitido na referida Portaria (0,2 mg/L e 0,7 mg/L, respectivamente) não apresentando, portanto, nenhum tipo de contaminação por metais tóxicos. Os metais mais abundantes foram: Na (1,7594 mg/L), Mg (0,3156 mg/L), K (0,2756 mg/L) e Ca (0,1644 mg/L). estando apenas uma amostra com teor de bário fora dos padrões da referida Portaria, indicando uma provável contaminação pontual durante a captação, envase ou devido à possível adição de sais de bário nessas águas

    Estatística multivariada aplicada na avaliação dos parâmetros químicos e físico-químicos da água engarrafada do município de Belém-PA / Multivariate statistics applied in the evaluation of chemical and physical-chemical parameters of bottled water in the municipality of Belém-PA

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    A estatística multivariada fornece ferramentas importantes no entendimento do comportamento de variáveis físico-químicas e químicas, permitindo traçar padrões de comportamento para diversas matrizes ambientais, como é o caso de águas minerais. Este trabalho teve por objetivo utilizar a estatística multivariada na avaliação de parâmetros químicos e físico-químicos em amostras de água engarrafada comercializada no município de Belém. Foram utilizados softwares de modelagem estatística, como os programas Statistica, Minitab 14 e Microsoft Excel para análise de correlação, Box Plot, ANOVA Fator Único, Análise de Agrupamentos Hierárquicos (HCA) e Análise das Componentes Principais (PCA). Os resultados mostraram que a maioria dos elementos químicos e variáveis físico-químicas se apresentou dentro da conformidade com a legislação e sem variações significativas. Os metais em maiores concentrações nas águas minerais tendem a possuir comportamentos semelhantes, como é o caso do K, Mg, Na, Ba e Ca. Os testes de PCA mostraram que a maioria das amostras avaliadas não se comportam de maneira semelhante, apresentando ainda como variáveis mais significativas salinidade, condutividade, Ba, Ca, K e Na, Al e Be. Concluiu-se que a estatística multivariada pode ser usada como instrumento na avaliação do comportamento de parâmetros químicos e físico-químicos das águas engarrafadas

    Single nucleotide polymorphisms in several porcine cathepsin genes are associated with growth, carcass, and production traits in Italian Large White pigs

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    To identify DNA markers associated with performance, carcass, and meat production traits including muscle postmortem cathepsin activity, sev- eral porcine genes encoding for lysosomal proteinases (cathepsin B, CTSB; cathepsin D, CTSD; cathepsin F, CTSF; cathepsin H, CTSH; cathepsin L, CTSL; and cathepsin Z, CTSZ) and for a cathepsin inhibitor (cys- tatin B) were investigated. Single nucleotide polymor- phisms were identified in CTSD, CTSH, CTSL, and CTSZ genes with a combination of in silico expressed sequence tag database mining and single-strand confor- mation polymorphism analysis. Sequencing and PCR- RFLP protocols were used to validate the identified polymorphisms. Allele frequencies at these loci were investigated in Italian Large White, Landrace, Duroc, Pietrain, Belgian Landrace, Hampshire, and Meishan breeds. Genotyping CTSD and CTSH markers made it possible to genetically map these genes to SSC 2 and 7, respectively. Markers in CTSD, CTSH, CTSL, and CTSZ genes, together with mutations we previously re- ported in cystatin B, CTSB, and CTSF genes, were genotyped in an Italian Large White sib-tested popu- lation (272 or 482 animals). For these animals, meat quality traits (cathepsin B activity, pH measured at 2 h postmortem, pH measured at 24 h postmortem, glyco- gen, lactate, and glycolytic potential of semimembrano- sus muscle) and EBV for ADG, lean cuts (LC), backfat thickness (BFT), ham weight (HW), and feed:gain ra- tio (FGR) were determined. Analyzed markers did not show any association with muscle cathepsin B activity. Thus, it could be possible that different genes, other than these investigated candidates, affect this trait, which is correlated with the excessive softness defect of dry-cured hams. The results of association analysis confirmed the effects we already reported in another study for CTSF on ADG (P = 0.008), LC (P = 0.001), and BFT (P = 0.02). Moreover, CTSD was associated with ADG, LC (P < 0.0001), BFT, HW, and FGR (P < 0.001); CTSH was associated with FGR (P = 0.026); and CTSZ was associated with ADG (P = 0.006), LC (P = 0.01), HW (P = 0.024), and FGR (P = 0.029). The biochemical and physiological functions of the lys- osomal proteinases, together with the results obtained in our investigation, suggest that the cathepsin gene family might play important roles affecting economic traits in pigs
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