Cytogenetic analysis of chorionic villi for prenatal diagnosis: An ACC collaborative study of U.K. data

A prospective 3-year collaborative study was undertaken in 1987 to collect cytogenetic data from diagnostic chorionic villus samples (CVS) in the U.K. in order to determine the predictive value of the chromosome abnormalities encountered. Twenty-seven laboratories contributed a total number of 7595 cases, of which 97·6 per cent were successful. Excluding single cell anomalies, a total of 480 cytogenetic abnormalities were reported, of which 137 were familial structural rearrangements and 343 were de novo problems. Non-mosaic trisomies of chromosomes 13, 18, and 21 (n=157), non-mosaic sex chromosome abnormalities (n=33), and triploidy (n=6) were all confirmed in cells of fetal origin where follow-up information was available. Of the nine remaining non-mosaics including tetraploidy, trisomies of other autosomes, and extra markers, only a trisomy 16 and a case of a supernumerary marker proved genuine. Eighty-eight cases of mosaicism were reported to the study, of which only nine were confirmed as genuine: two cases involving chromosome 13, one trisomy 18, two examples of extra marker chromosomes, three 45,X, and one 47,XXX. There were no reports of false-negative findings. Presumptive maternal cell contamination was encountered in 39 cases, a detected incidence of 0·5 per cent. Four cases of presumptive ‘vanishing twin’ were recorded: in three of these, direct preparations showed a female karyotype, whereas cultures indicated a male (with male fetuses in two cases). The fourth case was of a female fetus with male and female cells in the CVS cultures. Subtle structural chromosome abnormalities were missed in three instances. Accurate prediction of the fetal karyotype was shown to require detailed knowledge of both the nature and the distribution of abnormal cells in the extra-embryonic tissues. In many cases, this could only be made where results from direct preparations and cultured cells were available. A number of conclusions were reached from these and similar data in the literature regarding the reliability of chromosome findings in CVS.     

Seasonal trend of ambient PCDD/Fs in Tianjin City, northern China using active sampling strategy

The spatial concentrations, seasonal trends, profiles and congener pairs of ambient polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs) were investigated within a seasonally active sampling scheme during Jun 2008 and Jan 2009 in Tianjin City, northern China. The PCDD/F concentrations ranged 14.2-172 fg I-TEQ/m³ (average 69.3 fg I-TEQ/m³) in summer and (89.8-1.01) × 10³ fg I-TEQ/m³ (average 509 fg I-TEQ/m³) in winter, respectively, except for the E-waste dismantling site where much higher values were observed (1.04 × 10³ fg I-TEQ/m³ in summer and 7.123 × 10³ fg I-TEQ/m³ in winter). The results indicated a significantly seasonal trend with higher TEQ values in winter as compared with summer, which could be related to increased emission sources and seasonal variations of the atmospheric boundary layer height. 2,3,4,7,8-PeCDF was the dominant contributor to the total PCDD/F toxic equivalents, and 2,3,7,8-TCDD was detected at almost all the sampling sites in winter. Most of the similarly substituted PCDD/F congener pairs exhibited high correlations, suggesting that they might have similar environmental fate or sources. But different seasonal and spatial distributions of PCDD/F concentrations indicated that the emission sources might be intermittent.     

便携式GC/MS对空气中苯系物的定量分析方法研究

文章采用简单快速的采气袋配气方式,以苯系物为例,研究了便携式GC/MS对大气中痕量有机污染物的快速定量测定方法。分别在Full scan和建立的SIM扫描方式下对苯系物标准样品进行了测定。对比实验结果表明,Full scan和SIM两种扫描方式下苯系物测定结果的相对标准偏差分别在5.1%~28.4%和13%~19%之间,回收率范围分别为46%~186%和60%~110%,方法检出限范围分别为2.504~10.63μg/m3和0.494~2.399μg/m3。总体而言,SIM方式在测定结果的精密度与准确度上均优于Full scan方式。室内外空气样品的测试结果映证了SIM方式在对痕量有机污染物测定的优势。     

巢湖沉积物有效磷的原位高分辨分析研究

将两种原位被动采样技术——高分辨平衡式间隙水(HR-Peeper)与氧化锆薄膜梯度扩散技术(Zr-oxide DGT)相结合,分别对巢湖西半湖7个点位溶解态反应性磷(cPW)和有效磷(cDGT)进行原位测定分析,cPW和cDGT在大部分沉积物剖面的分布相似或局部相似,说明不同深度沉积物固相有效磷组分对间隙水SRP的缓冲能力较接近.利用界面扩散通量和cDGT/cPW比值(R)表征沉积物磷的活性,从巢湖湖心向南淝河入湖口方向,界面以下6 mm的cPW、cDGT和扩散通量的变化基本一致,均呈递增趋势,表明沉积物磷的污染水平在增加;R值变化较小,说明沉积物界面处的缓冲能力差异不明显.     

我国公众环境保护意识的调查与分析

本文根据一次大规模的抽样调查资料，初步分析了我国公众环境保护意识的现状，认为从总体上看，公众的环保意识水平偏低；公众的环境资源况颇具特色；在经济发展与环境保护之间出现明显矛盾时，半数公众能够优先考虑环境保护；大多数公众认为环境保护与个人有关，但对个人的努力信心不足；超过七成的公众表示愿意为环境保护支付一定费用，但对高收入阶层普遍寄予较高的期望；公众有一定的依法保护环境的心理基础，但法律知识又非常缺乏。     

Chorionic villi sampling changes maternal serum alpha-fetoprotein

Second trimester amniocentesis has traditionally been utilized for prenatal genetic diagnosis. Chorionic villi sampling (CVS) is presently offered as an alternative. The occurrence of fetomaternal bleed (FMB) during CVS could increase the rate of post sampling abortion and, additionally, be of significance in patients at risk for isoimmunization. Detection and quantitation of FMB can be accomplished by the determination of changes in maternal serum alpha-fetoprotein (MSAFP) before and after CVS.     

Fetal blood sampling via the umbilical cord using a needle guided by ultrasound report of 66 cases

Pure fetal blood has been aspirated in utero from the umbilical vein near the placental insertion of the cord using a twenty gauge needle under ultrasound guidance. Sixty-six samples were taken on 63 pregnancies between 17 and 32 weeks of gestation. One to two millilitres of blood can be obtained easily without amniotic fluid dilution or contamination by maternal blood, as confirmed by the measurements of the mean corpuscular volume, the histogram distribution of the red blood cells and the hematocrit. In all cases the Kleihauer test and isoelectrofocusing of the hemoglobins were performed. Coagulation factors were also studied in 60 cases. In 17 cases a medical abortion was voluntarily induced after the procedure, and the follow-up was normal during the observation period after sampling. In the other cases, pregnancies have continued normally and twelve healthy babies have already been born.