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This paper describes a sensitive method for the detection of precipitation bands in the qualitative acetylcholinesterase (AChe) gel test. This method–dark field illumination–is compared with two existing methods of detection: epi-illumination of unstained gels and transillumination of dithio-oxamide stained gels. The comparison has been carried out on a selected series of 271 amniotic fluid samples, taken before the 22nd week of gestation. All 96 samples from normal pregnancies were scored as negative with all three visualization methods. For the detection of neural tube defects (NTD) and omphaloceles, dark field illumination proved to be more efficient than epi-illumination or dithio-oxamide staining. In one case of another congenital defect, we obtained a positive result with dark field illumination, and a negative one with the other detection methods. It is concluded that dark field illumination was shown to be the most sensitive method for the detection of precipitation bands. 相似文献
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H. Thom A. G. M. Campbell V. Farr P. M. Fisher M. H. Hall G. H. Swapp E. S. Gray 《黑龙江环境通报》1985,5(1):15-19
Over the three years period 1980–1982, 18 256 pregnancies in the Grampian Region of N-E Scotland including the islands of Orkney and Shetland were screened for raised levels of maternal serum alpha fetoprotein (MSAFP) in the second trimester. Thirty six cases of fetal open neural tube defect in singletons were detected (18 anencephaly and 18 spina bifida). Four additional cases of open spina bifida were associated with normal MSAFP levels although two of these were detected by amniotic fluid AFP measurement when amniocentesis was carried out because of previous NTD history. A further three cases of open spina bifida and two of anencephaly occurred in unscreened pregnancies. The MSAFP screening programme alone was thus instrumental in reducing the birth incidence of open neural tube defects by 36 out of 45 cases (80 per cent) in singletons. 相似文献
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S.K. Jha P. Lenka S. Gothankar R.M. Tripathi V.D. Puranik D.T. Khating 《Journal of environmental radioactivity》2009
The gross alpha and gross beta activities were estimated for radiological assessment of surface water quality around the proposed uranium mining site Kylleng Pyndengsohiong Mawthabah (Domiasiat), West Khasi Hills District, Meghalaya situated in a high rainfall area (12,000 mm) in India. 189 Surface water samples were collected over different seasons of the year from nine different locations covering around 100 km2. Gross beta activities were found to vary from 144 to 361 mBq/L which is much below the prescribed WHO limit of 1000 mBq/L for drinking water. Gross alpha activities varied from 61 to 127 mBq/L. These values are much below the reported gross alpha values by other countries. In about 7% of the samples the alpha activities remain exceeded the WHO guideline limit of 100 mBq/L. Surface water samples collected during the summer season of the year show higher activity whereas low activity was found from samples collected during monsoon season. Results show that all water sources are acceptable as drinking water for human consumption from the radiological point of view, the higher gross alpha concentrations in a few locations remains so only for short duration during the summer season. 相似文献
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报道了对云南九大高原湖泊水体中总α、总β放射性水平的调查结果,并对调查结果进行了分析比较,为开展水体的环境辐射评价提供一定的依据。调查结果表明,这九大高原湖泊水体的总α、总β放射性水平属正常本底水平。 相似文献
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为从物种雌激素受体(ERα)敏感性差异的角度探索辽东湾野生梭鱼雌雄同体高发生率的一个可能原因,从梭鱼肝脏cDNA中扩增出长1113 bp的梭鱼ERα(sERα) DEF区片段,并以此构建pGBT9-sERα DEF 质粒,将其和pGAD424-TIF2质粒依次转入Y190酵母细胞中,建立了sERα物种特异性的酵母双杂交筛选系统.在此系统中测试了4种环境中主要的雌激素雌酮(E1)、17β-雌二醇(E2)、雌三醇(E3)及17α-炔雌醇(EE2)对梭鱼ERα的诱导活性,半数雌激素活性浓度(EC50)为3.7、2.4、1698.7、1.2nmol/L,分别是青鳉鱼ERα活性的4.6、2.3、3.4、3.3倍,说明梭鱼ERα对E1、E2、E3、EE2具有较高的敏感性,这为解释辽东湾梭鱼雌雄同体的高发生现象提供了重要线索. 相似文献
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