產(chǎn)品名稱(chēng)：CBG (Cortisol binding Globulin) 產(chǎn) 地：Demeditec 產(chǎn)品貨號(hào)：DEKIP1809 產(chǎn)品規(guī)格：100 Tests 產(chǎn)品說(shuō)明： Special remarks: Biological activity Transcortin or corticosteroïd?binding globulin (CBG) is a plasma α1-glycoprotein with a molecular weight of approximately 52000 Dalton. It contains a single steroid?binding site with an affinity (at 37°C) for cortisol of 3.107 M-1 and a somewhat lower affinity for progesterone. Since the plasma concentration of transcortin varies between 0.4 and 2.5 10-6M, the major fraction of cortisol in plasma is bound to this protein. This transcortin?bound cortisol is considered to be biologically inactive, whereas the unbound cortisol constitutes the active form of cortisol. The active fraction of plasma cortisol will thus depend on the concentration of transcortin. Clinical applications The plasma concentration of transcortin shows little or no diurnal variation and no marked differences are observed in ***** subjects according to age, sex or menstrual cycle. In umbilical cord blood, however, transcortin is present at half of the normal ***** level and prepubertal children have somewhat higher levels than *****s. Estrogen therapy or estrogen impregnation during pregnancy causes a very marked increase of the transcortin concentration. Decreased levels of transcortin are observed in several conditions : hypoproteinemia, Cushing's syndrome or corticoïd treatment and in some cases of vitamin B12 deficiency. Extremely low levels of transcortin have been reported in a few patients with septic shock. Furthermore, a rare inherited form of hypotranscortinemia has been described. The most important clinical application of transcortin measurements consists of the interpretation of cortisol levels, since it allows to assess the unbound cortisol concentration, which is biologically active. Indeed, the concentration of unbound cortisol can be calculated from the concentration of total cortisol and that of transcortin on the basis of mass action. The results of this method correlate well with those obtained by centrifuged ultrafiltrations. PRINCIPLES OF THE METHOD A fixed amount of 125I labelled CBG competes with the CBG to be measured present in the sample or in the calibrator for a fixed amount of anti-CBG antibody sites, which are bound to the goat anti mouse (GAM) antibodies immobilized to the wall of a polystyrene tube. After 2 hours incubation at room temperature, an aspiration step terminates the competition reaction. The tubes are then washed with 2 ml of working wash solution and aspirated again. A calibration curve is plotted and the CBG concentrations of the samples are determined by dose interpolation from the calibration curve. 上海玉博生物技術(shù)有限公司在為生命科學(xué)領(lǐng)域提供豐富的產(chǎn)品與信息資源方面處于****地位，公司提供的產(chǎn)品涵蓋了二十多個(gè)國(guó)家近五十萬(wàn)種產(chǎn)品，而且產(chǎn)品的數(shù)量與信息在不斷的增長(zhǎng)和更新，公司提供的產(chǎn)品能夠使生命科學(xué)工作者加快對(duì)生物化學(xué)，分子生物學(xué)，細(xì)胞生物學(xué)以及蛋白質(zhì)組學(xué)研究的認(rèn)知，以及分子診斷和臨床醫(yī)學(xué)領(lǐng)域的應(yīng)用。
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