971 resultados para 17 beta-estradiol


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The microorganism Mucor piriformis transforms androst-4-ene-3,17-dione into a major and several minor metabolites. X-ray crystallographic analysis of two of these metabolites was undertaken to determine unambiguously their composition and chirality. Crystals belong to the orthorhombic space-group P2(1)2(1)2(1), with a = 7.199(4) angstrom and a = 6.023(3) angstrom, b = 11.719(3) angstrom and b = 13.455(4) angstrom, c = 20.409(3) angstrom and c = 20.702(4) angstrom for the two title compounds, respectively. The structures have been refined to final R values of 0.060 and 0.040, respectively.

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Malignant pleural mesothelioma is an asbestos-related neoplasm with poor prognosis, refractory to current therapies, the incidence of which is expected to increase in the next decades. Female gender was identified as a positive prognostic factor among other clinical and biological prognostic markers for malignant mesothelioma, yet a role of estrogen receptors (ERs) has not been studied. Our goal was to investigate ERs expression in malignant mesothelioma and to assess whether their expression correlates with prognosis. Immunohistochemical analysis revealed intense nuclear ER beta staining in normal pleura that was reduced in tumor tissues. Conversely, neither tumors nor normal pleura stained positive for ER alpha. Multivariate analysis of 78 malignant mesothelioma patients with pathologic stage, histologic type, therapy, sex, and age at diagnosis indicated that FRO expression is an independent prognostic factor of better survival. Moreover, studies in vitro confirmed that treatment with 17 beta-estradiol led to an ER beta-mediated inhibition of malignant mesothelioma cell proliferation as well as p21(CIP1) and p27(KIP1) up-regulation. Consistently cell growth was suppressed by ER beta overexpression, causing a G(2)-M-phase cell cycle arrest, paralleled by cyclin B1 and survivin down-regulation. Our data support the notion that ER beta acting as a tumor suppressor is of high potential relevance to prediction of disease progression and to therapeutic response of malignant mesothelioma patients. [Cancer Res 2009;69(11):4598-604]

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The ovariectomized (OVX) rat, a preclinical model for studying postmenopausal bone loss, may also be used to study differences in alveolar bone (AB). The objectives of this study were to quantify the differences in AB following estrogen replacement therapy (ERT), and to investigate the relationship between AB structure and density, and trabecular bone at the femoral neck (FN) and third lumbar vertebral body (LB3). Estrogen treated rats had a higher bone volume fraction (BV/TV) at the AB region (9.8% P < 0.0001), FN (12% P < 0.0001), and LB3 (11.5% P < 0.0001) compared to the OVX group. BV/TV of the AB was positively correlated with the BV/TV at the FN (r = 0.69 P < 0.0001) and the LB3 (r = 0.75 P < 0.0001). The trabecular number (Tb.N), trabecular separation (Tb.Sp), and structure model index (SMI) were also positively correlated (P < 0.05) between the AB and FN (r = 0.42, 0.49, and 0.73, respectfully) and between the AB and LB3 (r = 0.44, 0.63, and 0.69, respectfully). Given the capacity of AB to respond to ERT, future preclinical drug/nutritional intervention studies aimed at improving skeletal health should include the AB as a region of interest (ROI).

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Tesis (Maestría en Ciencias con Especialidad en Biología Molecular e Ingeniería Genética) U.A.N.L.

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Since the alkyl esters of p-hydroxybenzoic acid (parabens) can be measured intact in the human breast and possess oestrogenic properties, it has been suggested that they could contribute to an aberrant burden of oestrogen signalling in the human breast and so play a role in the rising incidence of breast cancer. However, although parabens have been shown to regulate a few single genes (reporter genes, pS2, progesterone receptor) in a manner similar to that of 17 beta-oestradiol, the question remains as to the full extent of the similarity in the overall gene profile induced in response to parabens compared with 17 beta-oestradiol. The GE-Amersham CodeLink 20 K human expression microarray system was used to profile the expression of 19881 genes in MCF7 human breast cancer cells following a 7-day exposure to 5 x 10(-4) m methylparaben, 10(-5) m n-butylparaben and 10(-8) m 17 beta-oestradiol. At these concentrations, the parabens gave growth responses in MCF7 cells of similar magnitude to 17 beta-oestradiol. The study identified genes which are upregulated or downregulated to a similar extent by methylparaben, n-butylparaben and 17 beta-oestradiol. However, the majority of genes were not regulated in the same way by all three treatments. Some genes responded differently to parabens from 17 beta-oestradiol, and furthermore, differences in expression of some genes could be detected even between the two individual parabens. Therefore, although parabens possess oestrogenic properties, their mimicry in terms of global gene expression patterns is not perfect and differences in gene expression profiles could result in consequences to the cells that are not identical to those following exposure to 17 beta-oestradiol. Copyright (c) 2006 John Wiley & Sons, Ltd.

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Neste estudo, foram utilizadas 7 cadelas sem raça definida, adultas e hígidas, copuladas com macho hígido, após exame andrológico, para acompanhamento das variações hormonais de progesterona, 17b-estradiol e cortisol a partir do final do próestro, durante o estro e diestro gestacional em fêmeas da espécie canina. As avaliações séricas do cortisol foram iniciadas no período de estro. A citologia vaginal esfoliativa foi utilizada como parâmetro auxiliar para a determinação das fases do ciclo estral, mais especificamente para análise do melhor momento para cópula, através da presença das células superficiais queratinizadas visibilizadas nas lâminas. Os resultados obtidos mostraram concentrações médias de progesterona elevando-se discretamente no final do próestro (de 1,56 para 2,85ng ml-1), concomitante com o início do declínio dos valores de estradiol no mesmo período (de 20,93 para 18,81pg ml-1). Durante a gestação pôde-se observar concentrações elevadas de progesterona (36,90ng ml-1), havendo declínio apenas no terço final (4,10ng ml-1), quando também pôde ser notada, por um momento, ligeira elevação das concentrações médias de 17b-estradiol (2,46pg ml-1). O aumento do cortisol sérico foi notado na última semana da gestação havendo, antes disso, alterações significativas (P<0,05) nas concentrações séricas baseadas nos padrões descritos em literatura. No pós-parto imediato a redução do cortisol sérico (6,52ng ml-1) foi considerada relevante de acordo com as concentrações detectadas na última semana da gestação (22,27ng ml-1). A progesterona esteve mantida em níveis basais no pós-parto imediato (< 1ng ml-1).

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)