Base de dados : IBECS
Pesquisa : D01.625.062.374 [Categoria DeCs]
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Fotocópia
Id: 052504
Autor: Mesch, Viviana; Ferreiro, Lydia; Grupito, Fernando; Sciarretta, Liana; Río, Alberto del.
Título: Comparación de dos métodos para la determinación de testosterona biodisponible en mujeres / Comparison of two methods for bioavailable testosterone assessment in women
Fonte: Endocrinol. nutr. (Ed. impr.);54(2):89-95, feb. 2007. tab, graf.
Idioma: Es.
Resumo: Fundamento y objetivo: La evaluación androgénica en la mujer es requerida en el diagnóstico de diversas afecciones tales como irregularidades menstruales, hirsutismo y acné, en las cuales se prefiere medir la testosterona biodisponible a la testosterona total, ya que la primera refleja la testosterona biológicamente activa. Ésta puede determinarse mediante una técnica de precipitación selectiva o por cálculo a partir de la medición de testosterona total y de la globulina transportadora de esteroides sexuales (SHBG). Nuestro objetivo fue comparar los resultados de testosterona biodisponible obtenidos por precipitación con sulfato de amonio con los calculados en 4 grupos de mujeres con diferentes concentraciones androgénicas. Pacientes y métodos: Se estudió a 27 mujeres normales con ciclos menstruales regulares (A), 26 mujeres hiperandrogénicas (B), 11 mujeres hipertiroideas (C) y 15 mujeres embarazadas normales (D). Se determinó en todos los casos testosterona total y SHBG para el cálculo de testosterona biodisponible, la cual fue evaluada también por precipitación con sulfato de amonio. Resultados: Se encontró una correlación significativa entre los dos métodos para evaluar testosterona biodisponible en los primeros 3 grupos, pero no en el grupo D. En los grupos A y C, el análisis de concordancia de Bland y Altman mostró un sesgo bajo. Los grupos B y D presentaron un sesgo más alto que los grupos A y C, sin superposición de valores entre mujeres normales e hiperandrogénicas. Conclusiones: La determinación de testosterona biodisponible por cálculo es equivalente a medirla por precipitación con sulfato de amonio en mujeres normales, hiperandrogénicas e hipertiroideas, no así en mujeres embarazadas (AU)

Background and objective: Androgenic status evaluation is often required in women as a diagnostic tool in the assessment of menstrual irregularity, hirsutism and acne. There is good evidence that the non specifically bound testosterone (bioavailable To) more accurately reflects the clinical situation than total testosterone, so bioavailable To assessment is more useful in these women. The latter can be determined by a selective precipitation method or through a mathematical calculation that requires total testosterone and SHBG concentrations. The aim of our study was to compare bioavailable To levels obtained with the ammonium sulfate precipitation technique with those obtained with a mathematical calculation in four groups of women with different androgenic levels. Patients and methods: We studied 79 adult women divided into the following groups: 27 normal women with regular menstrual cycles (A), 26 hyperandrogenic women (B), 11 hyperthyroid women (C) and 15 normal pregnant women (D). All samples were assayed for total To and SHBG by chemiluminiscent methods in order to calculate bioavailable To, which was also determined by ammonium sulfate precipitation. Results: We found a significant correlation between the two methods for bioavailable testosterone in the first three groups but not in group D. In groups A and C, Bland and Altman correlation showed a low bias. Groups B and D showed higher bias than groups A and C, with no overlapping of values between normal and hyperandrogenic women. Conclusions: The mathematical calculation and the ammonium precipitation technique are equivalent in assessing bioavailable testosterone in normal, hyperandrogenic and hyperthyroid women but not in pregnant women (AU)
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Fotocópia
Id: 23286
Autor: Özkanca, R.
Título: Beta-Galactosidase activity of Escherichia coli under long-term starvation, alterations in temperature, and different nutrient conditions in lake water
Fonte: Int. microbiol;5(3):127-132, sept. 2002. graf, tab.
Idioma: en.
Resumo: beta-Galactosidase activity of Escherichia coli was investigated in response to long-term starvation, changes in temperature and the presence of certain nutrient sources in lake water. beta-Galactosidase activity decreased markedly in filtered-autoclaved lake water at 25 degrees C and 37 degrees C, whereas it remained almost constant at 4 degrees C and 15 degrees C for 60 days. Increases in beta-galactosidase activity were observed in response to the following nutrient sources: glycine, serine, methionine and ammonium sulfate at 4 degrees C; glycine and ammonium sulfate at 15 degrees C; glycine, serine, methionine and ammonium sulfate at 30 degrees C. Glycine addition led to an increase in beta-galactosidase activity of almost five and seven orders of magnitude at 15 degrees C and 30 degrees C, respectively. In addition, L-methionine had the strongest influence on beta-galactosidase activity, which was detected as an increase of seven and eleven orders of magnitude at 4 degrees C and 30 degrees C, respectively. The effect of several amino acids and other nitrogen sources depended on the concentration of the nutrient source and the temperature. The results showed that, in lake water, long-term starvation, temperature change, and variations in nitrogen sources alter beta-galactosidase activity. Those effects should be taken into account when monitoring coliforms from the environment (AU)
Responsável: ES1.1
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