Navegando por Palavras-chave "Endocrine Disruptors"

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    Eletrodos de ouro modificados com monocamadas auto-organizadas aplicados à determinação eletroanalítica de hormônios
    (Universidade Federal de São Paulo (UNIFESP), 2020-06-04) Batista, Fabio Henrique Ferreira [UNIFESP]; Oliveira, Lucia Codognoto de [UNIFESP]; Universidade Federal de São Paulo
    In this work, characterization studies of gold electrodes modified with self-organized monolayers of 3-mercaptopropionic acid (AuMPA) and 2-mercapto-5-methyl-benzimidazole (AuMMB) and their applications in the determination of hormones are presented. The characterization by cyclic voltammetry indicated the immobilization of the monolayer of the MPA thiol on the surface of the gold electrode; the characterization by electrochemical impedance spectroscopy (EIS) showed the increase in charge transfer resistance due to the presence of the monolayer and made it possible to estimate the electrode coverage of the modified electrodes AuMPA and AuMMB in 74.4 e 65.4%, respectively; in the characterization by Raman spectroscopy, the presence of several shifts attributed to the MPA and MMB species was observed, thus showing that the modification of the electrodes was in fact performed. The potential of the modified electrodes was evaluated in the electrochemical study of the hormonal endocrine disruptors estradiol and estrone; pH studies indicated the 1: 1 proton: electron ratio and potential sweep rate studies denoted an electrochemical diffusion-controlled process for both. In the voltammetric study of signal stability, greater peak current stability for hormones was obtained when using the AuMMB electrode after 10 successive voltammograms. After the optimization of the square wave voltammetry parameters, analytical curves for estrone over Au and AuMMB electrodes were obtained, with limits of detection (LOD) and quantification (LOQ) of 1.07x10-6 mol L-1 and 3.57x10-6 mol L-1 (Au); and 1.17x10-6 mol L-1 and 3.90x10-6 mol L-1 (AuMMB) in ultrapure water and limits of detection (LOD) and quantification (LOQ) of 7.53x10-7 mol L-1 and 2.51x10 -6 mol L-1 (Au); and 6.94x10-7 mol L-1 and 2.31x10-6 mol L-1 (AuMMB) in water collected in the Billings dam, respectively. From partition studies in the water/n-octanol system for estrone, logD values ​​were estimated at 1.02 and 1.08 (pH 10.0), and 2.10 and 1.35 (pH 12.0 ) in ultrapure water and water sample from Billings Dam, respectively. Thus, the presence of other organic compounds in the matrix influences the partitioning process and suggests the accumulation of this species in sediments when inserted in quiescent water bodies.
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    Sperm characteristics in a sample of healthy adolescents in São Paulo, Brazil
    (Escola Nacional de Saúde Pública Sergio Arouca, Fundação Oswaldo Cruz, 2002-04-01) Mori, Marcos Mitsuyoshi [UNIFESP]; Cedenho, Agnaldo Pereira [UNIFESP]; Koifman, Sergio; Srougi, Miguel [UNIFESP]; Universidade Federal de São Paulo (UNIFESP); Fundação Oswaldo Cruz Escola Nacional de Saúde Pública Departamento de Epidemiologia e Métodos Quantitativos em Saúde
    The article presents preliminary data from a prospective investigation in a sample of healthy 14-17-year-old students from a technical school in São Paulo, Brazil. Ninety-six Tanner stage 5 and thirty-one Tanner stage 4 adolescents were evaluated: testicular volume was measured using a Prader orchidometer, and semen analysis was performed according to standard procedures. Median testicular volume was 20.0ml among Tanner 5 students and 15.0ml in Tanner 4 students in both the right and left testes. No significant differences were found in sperm volume or motility. Median concentration was 66.0 million/ml for Tanner 5 and 47.0 million/ml for Tanner 4 subjects. Morphological patterns showed abnormal forms in 81.9% of Tanner 5 and 93.6% of Tanner 4 adolescents. Oligospermia (sperm concentration < 5 million/ml) was observed in 7.3% of Tanner stage 5 and 12.9% of Tanner stage 4 individuals. Azoospermia was observed in 3 students (1.8%), with counts less than 1.0 in 8 students (4.8%). The authors discuss the observed results, analyzing the potential implications arising from biological development and potential environmental exposures.