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排序方式: 共有909条查询结果,搜索用时 15 毫秒
41.
Dr. Yash P. Agrawal Päivi Ylikangas Markku T. Parviainen Ilkka M. Penttilä 《黑龙江环境通报》1994,14(12):1141-1149
The histochemical measurement of urea-resistant alkaline phosphatase from maternal blood neutrophils is known to have a high detection rate for the prenatal detection of Down's syndrome pregnancies. However, because the histochemical method is laborious and subjective to use, it has not gained widespread acceptance in prenatal screening programmes. We present a simple and objective method for the measurement of urea-resistant alkaline phosphatase by flow cytometry. The method should allow the design of larger studies aimed at evaluating the role of neutrophil urea-resistant alkaline phosphatase in the prenatal screening for Down's syndrome. 相似文献
42.
D. J. H. Brock 《黑龙江环境通报》1994,14(13):1243-1252
A number of different models of CF carrier screening have now been tested in pilot trials. Apart from opportunistic and cascade testing (which are strictly speaking not true forms of screening), the major programmes have been directed either to young adults in primary care or to pregnant women in antenatal clinics. Only in the latter form of screening has sufficient data been collected to allow conclusions to be reached on the optimum mode of delivery. It seems very probable that when CF carrier screening passes into routine service, it will be the antenatal couple model that is used. 相似文献
43.
内分泌扰乱化学品对动物的影响和作用机制 总被引:41,自引:5,他引:41
介绍了内分泌扰乱化学品(EDCs)的作用机制及其对野生动物影响的研究进展。内分泌化学品可能与性激素受体、甲状腺素受体和其他受体(如芳烃受体)结合,也可能通过影响动物体内激素的代谢而对动物的生长发育起调控作用。各实验室的重复实验不支持环境雌激素之间存在协同作用的结论。已报道过的人体和野生动物生殖缺陷中具有充分证据的暴露-效应关系的实例为数不多。尽管野生鱼类变性是英国河流中的一个普遍现象,但进一步的实验证明污水处理场出水中的天然和合成雌激素足以引起鱼类的变性反应,而不是先前怀疑的非离子表面活性剂降解产物。目前尚不能对EDCs对人体和野生动物的健康风险作出正确评价,并有待于进一步研究。 相似文献
44.
抗铬菌株的筛选鉴定及其生物学特性和吸附特性 总被引:1,自引:0,他引:1
利用微生物分离纯化技术,在培养基中加入不同浓度的Cr3+、Cr6+,经过长时间驯化,从污染土壤中筛选出2株对Cr具有较高抗性的菌株(A和B),对其进行了形态、生理生化特性及分子生物学鉴定,并研究了其最佳生长条件及对Cr3+的生物吸附规律。结果表明,菌株A和B分别为蜡状芽孢杆菌(Bacillus cereus)和米根霉菌(Rhizopus oryzae)。菌株A和B的最适生长pH值均为7,最适生长温度均为30℃,最佳装液量为80~100 mL(250 mL摇瓶)。在培养时间一定时,随着Cr3+浓度的增加,菌株对Cr3+的吸附率减少,而生物吸附量则逐渐增大;在Cr3+浓度一定时,随着培养时间的延长,菌体对Cr3+的吸附率呈现出先增加后减少的趋势,这与生物吸附量的变化趋势基本一致。在Cr3+浓度为100 mg/L时,菌株A和B对Cr3+的吸附率达到最大,分别为51.47%和46.36%。 相似文献
45.
46.
Kevin Spencer Adolfo W. Liao Charas Y. T. Ong Lut Geerts Kypros H. Nicolaides 《黑龙江环境通报》2001,21(9):718-722
Placenta growth factor (PIGF), an angiogenic factor belonging to the vascular endothelial growth factor family, pregnancy-associated plasma protein A (PAPP-A) and free β-human chorionic gonadotrophin (β-hCG) were measured in maternal serum from 45 pregnancies with trisomy 21, 45 with trisomy 18 and 493 normal controls at 10–13 completed weeks of gestation. In the normal pregnancies maternal serum PIGF levels increased exponentially with gestation. The median multiple of the median (MoM) PIGF concentration in the trisomy 21 group (1.26 MoM) was significantly higher (p<0.0001) than in the control group (1.00 MoM). In the trisomy 18 group the median PIGF was lower (0.889 MoM) but this did not quite reach significance (p=0.064). The corresponding median MoM values for PAPP-A were 1.00 MoM for the controls, 0.49 MoM for trisomy 21 and 0.16 MoM for trisomy 18. The median MoM values for free β-hCG were 1.00 MoM for the controls, 2.05 MoM for trisomy 21 and 0.38 MoM for trisomy 18. In the control group there was a small but significant correlation of PIGF with free β-hCG (r=+0.1024) and PAPP-A (r=+0.2288). In the trisomy 18 group there was a significant association between PIGF and free β-hCG (r=+0.2629) but not with PAPP-A (r=+0.0038). In the trisomy 21 group there was a small but significant association with PAPP-A (r=+0.1028) but not with free β-hCG (r=+0.0339). The separation of affected and unaffected pregnancies in maternal serum PIGF is small, and therefore it is unlikely that measurement of PIGF would improve screening for these abnormalities provided by the combination of fetal nuchal translucency and maternal serum PAPP-A and free β-hCG. Copyright © 2001 John Wiley & Sons, Ltd. 相似文献
47.
Wing Cheong Leung David Chitayat Gareth Seaward Rory Windrim Greg Ryan Jon Barrett Elizabeth J. T. Winsor 《黑龙江环境通报》2001,21(4):327-332
We retrospectively reviewed 309 amniotic fluid interphase fluorescence in situ hybridization (FISH) analyses performed from October 1995 to June 1999 to assess the role of interphase FISH in the management of patients at increased risk for fetal aneuploidies. Gestational age and indications for amniocentesis, clinical interventions after FISH results, as well as interventions after final culture reports were analyzed. There were 244 (79%) normal, 50 (16%) abnormal and 15 (5%) inconclusive FISH results. There were no false-positive or false-negative results, but there were nine (3%) clinically significant chromosomal abnormalities not detectable by FISH. Of the 50 women with abnormal FISH results, 26 (52%) elected to terminate the pregnancy prior to the availability of the standard chromosome analysis. In two of the fetuses with trisomy 21 no abnormalities were reported by ultrasound examination. Our experience indicates that interphase FISH results played an important role in decision making, especially for pregnancies close to 24 weeks' gestation. Standard karyotype analysis is still required for detection of chromosome abnormalities not detectable by interphase FISH techniques and for clarification of unusual or inconclusive FISH results. Copyright © 2001 John Wiley & Sons, Ltd. 相似文献
48.
Rita W. Driggers Helene Bernstein Michael Lantz Gail Stetten Cathleen S. Escallon Elizabeth Perlman Karin J. Blakemore 《黑龙江环境通报》2001,21(5):387-389
Non-mosaic trisomy 20 is rare in fetuses surviving beyond the first trimester. We report a case of a fetus with non-mosaic trisomy 20 in amniotic fluid cultures obtained during the prenatal evaluation of an unusual thoraco-abdominal mass which was found at autopsy to be pulmonary sequestration. Gross inspection and autopsy of the fetus revealed multiple anomalies. Copyright © 2001 John Wiley & Sons, Ltd. 相似文献
49.
Kevin Spencer 《黑龙江环境通报》2001,21(6):445-447
In a group of 149 women who had undergone routine first trimester screening using fetal nuchal translucency thickness (NT) and maternal serum free β-hCG and pregnancy associated plasma protein-A (PAPP-A) in two consecutive pregnancies the within person between pregnancy biological variability of these markers has been assessed. For fetal NT there was no correlation between NT MoM in the first and second pregnancy (r=0.0800). For maternal serum free β-hCG MoM a significant correlation was observed (r=0.4174) as was also found for PAPP-A MoM (r=0.3270). The implications for such between pregnancy marker association is that women who have an increased risk of Down syndrome in their first pregnancy are 1.5–2 times more likely to repeat this event in their next pregnancy. This observation may be useful in counselling women in the first trimester screening of a subsequent pregnancy. Copyright © 2001 John Wiley & Sons, Ltd. 相似文献
50.
粉煤灰分选工艺流程的改进 总被引:2,自引:0,他引:2
利用闲置设备进行流程改进,提高了粉煤灰的利用率,解决了制砖所需的细骨料。每年节省运灰费用200多万元,具有良好的经济效益和环境效益 相似文献