Ultrasound in prenatal diagnosis: polemics around routine ultrasound screening for second trimester fetal malformations

Ultrasound for routine fetal malformation screening has been polemical from its early beginning because of the very broad range of diagnosis rates disclosed, i.e. from 13% to 82%, average 27.5%. A review of available studies is proposed to assess objectively the efficacy of ultrasound, considering also economical, ethical and methodological aspects as influential factors for choosing a routine screening policy. The utility of fetal malformation diagnosis before birth is brought forward, including second opinion, karyotyping, poly-disciplinary case discussion prior to management. Method and material of reviewed studies considerably vary and might influence the sensitivity results, as the choice of the population sample and selection of pregnant women, gestation age at screening, distribution of malformation among systems or tracts, exclusion of some fetal malformation and the routine practice of autopsy. Efficiency of screening studies is compared, and among them Radius and Eurofetus studies. Average sensitivity is finally considered as satisfactory in the daily practice when operated by trained personnel. The importance of additional factors for successful screening are emphasized such as education, equipment quality and fetal ultrasound examination at different gestation age for a better understanding of natural history of fetal morphology. Copyright © 2002 John Wiley & Sons, Ltd.     

Comparative audit of booking and mid-trimester ultrasound scans in the prenatal diagnosis of congenital anomalies

During 1988 and 1989, 3565 women booked under consultants who performed an ultrasound scan at booking, whilst 4984 booked under consultants who performed a formal mid-trimester scan between 16 and 18 weeks. All significant anomalies diagnosed prenatally and in the neonatal period were recorded, the incidence in each group being 12.9/1000 and 9.83/1000, respectively (NS). The sensitivity of diagnosis before 20 weeks was 45 per cent in the ‘mid-trimester’ group (kappa 0.62) compared with 30 per cent in the ‘booking’ group (kappa 0.46), overall sensitivity of prenatal diagnosis, however, being similar in both groups (63 vs. 65 per cent, kappa 0.77 vs. 0.79). Cardiac anomalies were the single largest group which were not detected equally prenatally in both groups. This study shows that formal mid-trimester scanning leads to anomalies being detected significantly earlier in the antenatal period. Although not statistically significant, three lethal anomalies were missed prenatally in the ‘booking’ group which we would have expected to diagnose on a mid-trimester scan. These figures are discussed in the light of previous reports.     

Rare cell isolation using antibodies covalently linked to slides: application to fetal cells in maternal blood

We describe here a new type of method for isolation of rare cell populations in biological fluids. The method is based on the anthraquinone technology for covalent binding of molecules to a polymer surface. An anthraquinone molecule conjugated via a linker to an electrophilic group (AQ Immobilizer™ reagent, Exiqon A/S) is covalently bound to a polymer surface by UV irradiation. The electrophilic group of this AQ reagent can covalently bind a specific antibody directed against a specific cell marker. Applying a cell sample to the functional surface, the cells having the specific cell marker on the cell surface will bind to the antibody on the functional surface. Using this technique, even extremely small cell populations may be isolated. We succeeded in isolating fetal cells from maternal blood samples in the first trimester for chromosome defects genetic diagnosis. Copyright © 2003 John Wiley & Sons, Ltd.     

Complications of cordocentesis in high-risk pregnancies: Effects on fetal loss or preterm delivery

Between 1990 and 1993, 166 cases underwent cordocentesis and were followed for at least the following 4 weeks in the Prenatal Diagnosis and Therapy Centre of Vienna University. The indications for the procedure were structural malformations in 46·4 per cent of the cases, other high-risk diagnoses in 48·8 per cent, and maternal age over 35 years in only 4·8 per cent. We investigated retrospectively all cases of complications resulting in fetal loss or preterm labour. Abortion, intrauterine fetal death, chorioamnionitis, and preterm delivery occurred in 0·6, 5·4, 0·6 and 9·0 per cent of these cases, respectively, adding up to a total of 26 cases (15·7 per cent). Although this rate looks relatively high, 20 of the 26 cases had already displayed signs implying a complicated prognosis. Neither maternal age, gestational age, number of attempts, nor placental location correlated with fetal loss or preterm delivery. Significantly higher rates of fetal loss or preterm delivery were observed when cordocentesis was performed in cases diagnosed as duodenal/intestinal stenosis or hydrops–ascites–hydrothroax/hygroma colli (P=0·0488 and P=0·0005). The frequency of complications did not decrease as the experience of the operators increased.     

镉"加标"沉积物对泥鳅(Misgurnus anguillicaudatus)生物毒性研究

选择泥鳅(Misgurnus anguillicaudaus)作为受试生物,以泥鳅死亡率、血液红细胞数量、红细胞体积、红细胞微核率和核异常率作为测试指标,考察了沉积物中"加标"金属镉(Cd)的毒性状况,探讨了水体沉积物中重金属的生物毒性影响.结果表明:高有机质的粘土粉砂性沉积物能够有效吸附重金属镉;镉加标暴露组泥鳅的死...     

广西春旱的时空分布特征及成因分析

利用广西具有气候代表性的32个站点1961-2007年逐日降水量资料,引入季节无雨日作为划分干旱的标准,采用EOF分析等方法,分析了广西春旱的时空分布特征;并用NCEP再分析资料、NOAA海温资料、国家气候中心的74项环流特征量资料等,对广西春旱的成因进行了分析。结果表明:从时间变化看,广西春旱的趋势变化不明显,主要以年际、年代际变化为主,从空间分布看,广西春旱以全区一致性型为主要空间分布型;在春旱年,广西上空对流层低层出现偏南-西南气流距平强辐散异常,伴随有明显的水汽通量辐散异常,同时东亚大槽偏弱,阿留申低压明显减弱,中纬度大陆高压减弱,中高纬环流平直,不利于冷空气南下华南;广西春旱年前冬阿留申低压明显增强,大陆高压也增强,冷空气活动频繁,当前冬印缅槽偏弱时,广西春季发生干旱的可能性较大。