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81.
The potency of different substances for [3H]dihydrotestosterone ([3H]DHT) displacement from the bovine androgen receptor was tested. The phenylurea herbicide linuron and its derivative 3,4-dichloroaniline (3,4-DCA), which are found in sediments and surface waters, are known to displace bound testosterone from the rat androgen receptor. Because 3,4-DCA is rapidly taken up by fish and metabolised into 3,4-dichloroacetanilide (3,4-DCAc), it was investigated whether the displacement effects are attributable to 3,4-DCA or to 3,4-DCAc. The potency of 3,4-DCAc androgen receptor binding was compared with that of several phenylurea compounds. In a radioreceptor assay with calf uterus cytosol as androgen receptor preparation, the specific binding of [3H]DHT, the endogenous ligand, was completely displaceable by increasing concentrations of 3,4-DCAc. The relative binding affinities (RBA) of the various compounds were about 1/10(4) to 1/10(5) of that of DHT. 3,4-DCAc had the relative highest affinity (1.31 x 10(-4)), followed by linuron, 3,4-dichlorophenylurea, flutamide, 3,4-DCA and diuron with the lowest RBA (2.4 x 10(-5)). Hence the metabolism of xenobiotic compounds has to be considered to estimate potential ecotoxiocological effects. This test not only can be used to screen for androgen- and antiandrogen-like substances in environmentally relevant samples such as surface waters, but might also be applied for drug testing and for residue monitoring. 相似文献
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A. Breakstone C. D. Buchanan R. Campanini H. B. Crawley M. Cuffiani G. M. Dallavalle M. M. Deninno K. Doroba D. Drijard F. Fabbri A. Firestone H. G. Fischer H. Flöge H. Frehse W. M. Geist L. Gesswein G. Giacomelli R. Gokieli M. Gorbics M. Gorski P. Hanke M. Heiden D. Isenhower E. E. Kluge J. W. Lamsa T. Lohse R. Mankel W. T. Meyer T. Nakada M. Panter A. Putzer K. Rauschnabel B. Rensch F. Rimondi M. Schmelling G. P. Siroli J. Skeens R. Sosnowski M. Szczekowski O. Ullaland D. Wegener R. Yeung 《Zeitschrift fur Physik C Particles and Fields》1991,52(4):551-557
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Rock porosity determination by combination of X-ray computerized tomography with mercury porosimetry
P. Klobes H. Riesemeier K. Meyer J. Goebbels K.-H. Hellmuth 《Fresenius' Journal of Analytical Chemistry》1997,357(5):543-547
First results are described of coupling of mercury porosimetry with X-ray computerized tomography (CT) as a new combination
technique for rock porosity studies. This technique is suitable for rock samples with a pronounced mercury intrusion-extrusion
hysteresis and includes CT measurements before and after mercury intrusion. The entrapped portion of mercury, when the pressure
after the intrusion into the rock sample is reduced to 0.1 MPa, serves as a contrast agent in the porous network to localize
spatial distribution of rock porosity by CT. The results obtained show that the mercury intrusion and therefore the porosity
were quite different for the separate mineral phases. Therefore the combination of mercury porosimetry and computer tomography
can give 3-D data on mineral-specific porosity distributions with additional pore size information. In contrast to mercury
porosimetry as a single method, results of the combination technique with CT represent a direct visualization of porosity
variation and do not depend on any special pore network model.
Received: 2 July 1996 / Revised: 20 November 1996 / Accepted: 22 November 1996 相似文献