Flow sorting of fetal erythroblasts using intracytoplasmic anti-fetal haemoglobin: Preliminary observations on maternal samples

Monoclonal antibody to fetal haemoglobin (a₂γy₂) has been proposed as a fetal-specific reagent. We developed an intracellular staining protocol that combines fluorescein isothiocyanate or phycoerythrin conjugated anti-γ with the DNA binding dye Hoechst 33342 to identify and flow sort fetal erythroblasts from maternal blood. Our preliminary observations on anti-γ-positive cells sorted from four different pregnant women are described here, using fluorescence in situ hybridization (FISH) with chromosome-specific probes to identify fetal cells. Our data demonstrate that far fewer candidate fetal cells are sorted with this protocol than by current cell surface staining methods that employ the monoclonal antibody CD71. This results in increased fetal cell sorting purities. With this protocol, standard FISH techniques require modification due to the rigorous fixation with 4 per cent paraformaldehyde. Our initial data indicate the promise of this approach.     

First-trimester prenatal diagnosis in quintuplets: A practical approach using step-by-step embryo reduction

A multiple pregnancy of high rank may occur in a couple at risk for a Mendelian disorder. Prenatal diagnosis is hampered by the difficulty of (1) obtaining chorionic villi from each zygote arid (2) unequivocally relating each sample to the corresponding embryo. The calculation of the genetic risk according to the number of zygotes led us to propose a diagnostic strategy based on embryo reduction, a technique initially designed to improve the perinatal outcome of multiple pregnancies with normal embryos. We report a case in which this approach allowed rational use of first-trimester chorionic villus sampling in a quintuplet pregnancy at risk for non-ketotic hyperglycinaemia, resulting in the selective birth of unaffected twins.     

灰关联分析在故障树诊断中的应用

介绍一种灰色诊断法。在故障诊断模式识别中,运用灰关联分析,依据故障树的底事件重要度,通过关联度计算及排序,对故障树分析中,各种故障模式发生的可能性大小作出了准确的判断,从而为处理事故的先后、缓急提供了依据。     

Residual risk for cytogenetic abnormalities after prenatal diagnosis by interphase fluorescence in situ hybridization (FISH)

Results from conventional cytogenetic studies on 21 609 amniotic fluid specimens were analyzed retrospectively to determine the residual risk for a cytogenetic abnormality if interphase FISH, capable of only detecting aneuploidy for chromosomes 13, 18, 21, X and Y, was performed and did not reveal an abnormality. Detection rates (the probability of detecting a cytogenetic abnormality when an abnormality is present) and residual risks (the likelihood of a cytogenetic abnormality, in view of normal interphase FISH results) were calculated for the four major clinical indications for prenatal diagnosis (advanced maternal age, abnormal maternal serum screen indicating increased risk for trisomy 18 or trisomy 21, abnormal maternal serum screen indicating increased risk for neural tube defects and ultrasound abnormality). Differences in detection rates were observed to depend on clinical indication and presence or absence of ultrasound abnormalities. The detection rate ranged from 18.2 to 82.6% depending on the clinical indication. The detection rates of abnormalities significant to the pregnancy being evaluated (i.e. abnormalities excluding familial balanced rearrangements and familial markers) were between 28.6 and 86.4%. The presence of ultrasound abnormalities increased the detection rate from 72.2 to 92.5% for advanced maternal age and from 78.6 to 91.3% for abnormal maternal serum screen, indicating increased risk for trisomy 18 or trisomy 21. With regard to residual risk, the risk for a clinically significant abnormality decreased from 0.9–10.1%, prior to the interphase FISH assay, to a residual risk of 0.6–1.5% following a normal interphase FISH result in the 4 groups studied. Providing patients with detection rates and residual risks, most relevant to their situation (clinical indication and presence or absence of ultrasound abnormality) during counseling, could help them better understand the advantages and limitations of interphase FISH in their prenatal diagnostic evaluation. Copyright © 2003 John Wiley & Sons, Ltd.     

甘肃省农业高质量发展水平测度及制约因子研究

结合农业高质量发展的特征,构建农业高质量发展评价指标体系,采用熵值法、障碍因子诊断模型对甘肃省2009—2018年农业高质量发展水平和制约因素进行分析。结果发现:①2009—2018年,甘肃省农业高质量发展综合水平整体呈增长态势,但农业发展质量不高。②农业绿色发展和农业科技创新是甘肃省农业高质量发展的主要短板。③人力资本和生态环境保护是制约甘肃省农业高质量发展的主要因素。基于研究结果,提出强化政府职能、培育和引进高质量农业人才、贯彻新发展理念、构建生态补偿机制等加快甘肃省农业高质量发展的政策建议。