Detection of fetal HLA-DQα sequences in maternal blood: A gender-independent technique of fetal cell identification

The objective of this study was to detect fetal HLA-DQα gene sequences in maternal blood. HLA-DQα genotypes of 70 pregnant women and their partners were determined for type A1. We specifically sought couples where the father, but not the mother, had genotype A1. In 12 women, maternal blood samples were flow-sorted. Candidate fetal cells were isolated and amplified by using PCR primers specific for a paternal HLA-DQα A1 allele. Fetal HLA-DQα A1 genotype was predicted from sorted cells; amniocytes or cheek swabs were used for confirmation. Six of twelve sorted samples had amplification products indicating the presence of the HLA-DQα A1 allele; 6/12 did not. Prediction of the fetal genotype was 100 per cent correct, as determined by subsequent amplification of amniocytes or cheek swabs. We conclude that paternally inherited uniquely fetal HLA-DQα gene sequences can be identified in maternal blood. This system permits the identification of fetal cells independent of fetal gender, and has the potential for non-invasive prenatal diagnosis of paternally inherited conditions.     

Maternal age-specific risks for trisomies at 9—14 weeks' gestation

This study provides data on the incidence of fetal trisomies 21, 18, and 13 at 9–14 weeks' gestation in women aged 35–45 years and estimates of maternal age-specific risks in women aged 20–45 years. Our data from 5814 singleton pregnancies undergoing first-trimester karyotyping for the sole indication of maternal age ⩾ 35 years were combined with those from two previous reports and the incidence of the trisomies was calculated from a total of 15 793 pregnancies. Comparison of incidences at 9–14 weeks' gestation with published data at 15–20 weeks' gestation and in livebirths demonstrated that at birth the maternal age-specific incidence of trisomy 21 is 33 per cent lower than at 15–20 weeks' gestation and 54 per cent lower than at 9–14 weeks' gestation. Furthermore, the relative frequency of trisomies 18 and 13 decreases from 30 per cent at 9–14 weeks to 22 per cent at 15–20 weeks and 14 per cent at birth.     

Dystrophin protein and rflp analyis for fetal diagnosis and carrier confirmation of duchenne muscular dystrophy

A pregnant woman with indeterminate Duchenne muscular dystrophy (DMD) carrier status, but with DMD diagnosed in her deceased brother (unavailable for study), presented for prenatal diagnosis, intending to continue the pregnancy only if proven unaffected with DMD with near absolute certainty. Creatine kinase (CK) assays to clarify carrier status were inconclusive. Male sex in the fetus was identified, but DNA restriction fragment length polymorphism (RFLP) analysis was not yet available to this centre to investigate the possible transmission of the DMD gene, and the pregnancy was terminated. Tissue histology and dystrophin protein analysis demonstrated the absence of DMD. In a situation with proven maternal carrier status, future fetal inheritance of the opposite maternal X chromosome would indicate the presence of DMD. However, maternal carrier status remained in doubt through a second pregnancy, even with RFLP studies, and was finally established when dystrophin analysis confirmed the presence of DMD in the second fetus. Histologic findings are presented, contrasting features in the two fetuses. The value of dystrophin analysis for establishing the diagnosis of fetal DMD, in this case proving maternal carrier status in a difficult situation, and for demonstrating DMD gene:RFLP haplotype relationships is illustrated.     

Prenatal diagnosis of endocardial fibroelastosis

In a case of fetal heart failure caused by endocardial fibroelastosis, prenatal echocardiography clearly demonstrated; a thickened endocardium. We therefore suggest that an abnormal endocardium may be detected in utero by ultrasound, thus representing an important clue in the differential diagnosis of fetal nonimmune hydrops and in the evaluation of pregnancies at risk for endocardial fibroelastosis.     

Hepatic calcifications in a fetus with trisomy 9 that underwent cordocentesis

Foci of calcification were observed at autopsy in the liver of a fetus with complete trisomy 9 on which two cordocenteses had been performed. It is suggested that liver calcifications are a possible complication of the procedure. As several other cases of calcifications in the liver and other organs of fetuses with autosomal trisomies have been described without a history of cordocentesis, further studies should be carried out to determine whether fetuses with chromosomal anomalies are more prone to thrombus formation and embolization.     

真,假草本咖啡种子的鉴别

在对草本咖啡（Ｃａｓｓｉａｓｏｐｎｅｒａｉｉｎｎ）、望江南（ＣａｓｓｉｓｏｃｃｉｄｅｎｔａｌｉｏＬ．）和决明（ＣａｓｓｉａｔｏｒａＬ．）种子的大小、颜色、形态进行了观察、研究，并对其形态特征进行了解剖学的分析后，提出了鉴别３种种子的方法。     

基于可靠度和性能的结构整体地震易损性分析

地震风险分析包括地震危险性分析、地震易损性分析和地震灾害损失评估3个方面，其中，地震易损性分析可以预测结构在不同等级地震作用下发生各级破坏的概率，因此对结构的抗震设计、加固和维修决策具有重要的应用价值。传统的结构地震易损性分析主要采用经验方法或蒙特卡洛模拟法绘制地震易损性曲线。首先介绍地震风险分析的基本原理，然后提出结构整体地震易损性的概念，针对传统方法存在的问题，将结构的可靠度方法与基于性能的抗震设计理论结合起来，提出了基于可靠度和性能的结构整体地震易损性分析方法，并采用有限元可靠度方法进行了结构地震易损性的计算。以结构的最大层间相对变形作为整体性能指标，对某5层2跨钢框架结构进行了地震易损性分析，绘制了其在不同地震作用下对应不同性能水准要求的地震易损性曲线。     

对"十一五"期间加快环保产业结构调整的有关思考

通过介绍“十一五”期间加快进行我国环保产业结构调整的迫切性,提出了应当采取的措施及要处理好的几个关系。     

基于非概率可靠性的离散变量结构优化设计

目的针对工程结构设计中因材料供应规范限制使得设计变量不能连续取值以及材料性能波动、外界载荷偏差等不确定性问题,探索研究非概率可靠性在离散变量结构优化设计中的应用。方法以桁架结构杆件截面直径为设计变量、结构质量极小化为目标,考虑材料强度极限与外部载荷的不确定性,建立具有非概率可靠性指标约束的离散变量结构可靠性优化模型,并采用遗传算法求解离散变量结构优化设计问题。结果求解获得了三杆、十杆超静定桁架杆件截面直径最优组合,得到的优化结果相较确定性优化结果更具鲁棒性。结论非概率可靠性模型对于解决工程中设计变量具有离散性和不确定性的优化设计问题具有可行性。