Does nuchal translucency have a role in fetal cardiac screening?

Increased nuchal translucency is the strongest single marker for chromosomal abnormality. Consequently, it is currently becoming established as the foundation of most early screening programmes for Down syndrome. In the absence of chromosomal abnormality, increased nuchal translucency has been shown to be associated with other congenital anomalies including cardiac defects. Several datasets have now reported this association and here these are reviewed to assess the effectiveness of nuchal translucency measurement as a screening tool for the prenatal detection of congenital heart disease. Copyright © 2004 John Wiley & Sons, Ltd.     

Measurement of cholinesterases in amniotic fluid using a naphthyl acetate as substrate: A possible initial test for prenatal diagnosis of open neural tube defects

A quantitative method for cholinesterases in amniotic fluid using the non-specific substrate α naphthyl acetate and the cholinesterase-specific inhibitor, eserine, is described. This assay was used to test 671 samples of amniotic fluid. The diagnoses for fetal ONTDs, based on the levels of AChE + ChE, were compared with those made for the same samples by the AFP method. Correct diagnoses were made by both methods with amniotic fluid from 35 women carrying fetuses with ONTDs and 631 carrying normal fetuses. There were five false-positive test results for normal fetuses by both methods when the cut-off points were 5 standard deviations above the mean for AFP and above the upper limit of the normal range (7. 5 milliunits) for cholinesterase (AChE + ChE). None of the false-positive samples from either method had the acetylcholinesterase band of activity characteristic of ONTDs after gel electrophoresis. In addition to the above 671 samples, 37 pregnancies with serious fetal abnormalities other than ONTDs were tested. Two were identified by both the AFP and AChE + ChE methods, two more by AFP assay and one other by the AChE + ChE assay.     

Where are the Sunday babies? II. Declining weekend birth rates in Switzerland

Birth dates from almost 3 million babies born between 1969 and 2005 in Switzerland were analyzed for the weekday of birth. As in other countries but with unprecedented amplitude, a very marked non-random distribution was discovered with decreasing numbers of births on weekends, reaching -17.9% in 2005. While most of this weekend births avoidance rate is due to fewer births on Sundays (up to -21.7%), the downward trend is primarily a consequence of decreasing births on Saturdays (up to -14.5%). For 2005, these percentages mean that 3,728 fewer babies are born during weekends than could be expected from equal distribution. Most interestingly and surprisingly, weekend birth-avoiding rates are significantly correlated with birth numbers (r = 0.86), i.e. the lower the birth number per year, the lower the number of weekend births. The increasing avoidance of births during weekends is discussed as being a consequence of increasing numbers of caesarean sections and elective labor induction, which in Switzerland reach 29.2 and 20.5%, respectively, in 2004. This hypothesis is supported by the observation that both primary and secondary caesarean sections are significantly correlated with weekend birth avoidance rates. It is therefore likely that financial aspects of hospitals are a factor determining the avoidance of weekend births by increasing the numbers of caesarean sections.     

腐蚀缺陷管道评价标准保守性对比分析

针对标准SY/T6477-2000和标准API RP579-2007 中腐蚀缺陷管道评价判据问题,研究了标准中各项判据及其算法,计算了不同评价标准对于同一腐蚀缺陷的评价结果,并对比分析了不同参数变化情况与评价结果保守性关系。结果表明,不同评价标准所得的缺陷管道判据参数值之间存在差异,即各评价标准的保守性不同,不同评价标准适用于不同的均匀腐蚀或局部腐蚀缺陷管道情况。以此有效防止使用标准时造成差错,同时为今后相关标准的修订尽可能提供有益的帮助。     

论我国能源就地转化概念的完善

我国能源就地转化的概念虽已有两个定义,但它们没有完全反映能源就地转化本身所具有的内在特点和发展的必然趋势。通过对之进行深入研究,从能源就地转化扩大资源地能源与能源转化设备消费内需、调整资源地与能源消费地的经济结构、转变其经济增长方式、增强资源地的发展能力、缓解我国的能源运输压力和缩小我国地域间发展差距6个方面对之予以完善。     

Pt-Cu/TiO2{001}纳米片用于CO2加氢制甲醇反应的研究

以高暴露{001}晶面的TiO₂纳米片为载体,利用共还原法负载0.5%的Pt和一定量的Cu得到Pt-Cu/TiO₂{001}催化剂,并在P=3.0 MPa,T=200~300℃,V（N₂）：V（H₂）：V（CO₂）=8：69：23,空速（WHSV）=3600 mL·g^-1·h^-1反应条件下评价了催化剂催化CO₂加氢制甲醇的反应性能.XRD、XPS、EPR和CO₂-TPD等的表征表明,与催化剂Cu/TiO₂相比,引入Pt后,催化剂由于金属Pt的电子促进作用使负载的金属与载体之间的相互作用更强,进而有利于稳定Cu颗粒尺寸且载体形成了更多缺陷（如氧空位、Ti³⁺）.因此,Pt-Cu/TiO₂{001}催化剂的金属与载体界面上的活性位点更多,从而表现出更好的CO₂活化能力和甲醇生成性能.     

Normal and abnormal fetal cardiac anatomy

The heart is often perceived as a difficult organ to understand by ultrasound during fetal life. This is undoubtedly reflected in the low detection rate of cardiac abnormalities as compared to those of most other organ systems in the fetus. In this article we start by updating classical concepts of cardiac embryology, many of which were previously difficult to understand since they were overly simplistic or purely observational. We then lead on to the structure and growth of the fully formed fetal heart where we review the anatomy and ultrasound appearances in detail and provide comparisons with major abnormalities. We emphasise the fact that a solid understanding of cardiac anatomy can enable those involved in fetal medicine to make full use of the views of the heart that are obtained by ultrasound and which are often only transient. Copyright © 2004 John Wiley & Sons, Ltd.     

An association between fetal abdominal wall defects and elevated levels of human chorionic gonadotropin in mid-trimester

We analysed maternal serum human chorionic gonadotropin (hCG) in 16 pregnancies with fetal abdominal wall defects previously identified prenatally by elevated maternal serum alpha-fetoprotein (AFP) or at birth. The AFP levels had a mean of 6·38 MOM (range 0·34–15·65), as expected with these defects. The hCG levels had a mean of 1·82 MOM (range 0·23–4·11). The hCG levels in five pregnancies (31·25 per cent) were above 2·30 MOM. Elevated levels of hCG may be associated with fetal abdominal wall defects.     

Transverse limb reduction defects after chorion villus sampling: A retrospective Cohort study

A retrospective cohort study was performed in five Italian obstetrical centres from 1984 to 1991 in order to verify the association between chorionic villus sampling (CVS) and transverse limb reduction defects (TLRDs). TLRD rates by period of gestation at CVS were calculated, and the study's results were compared with data from the general population. Of the 3430 pregnancies for which CVS was performed, 2759 had a known outcome. The overall rate for TLRDs was 1 in 1143 CVS pregnancies, four times higher than that of the general population in Italy (1 in 4458). The rate of TLRDs was 2·9/1000 for CVS performed at 9 weeks' gestation and 1·0/1000 for CVS at 10 weeks' gestation. A scalp defect was detected in a pregnancy in which CVS was performed at 10 weeks. A high proportion of pregnancies lost to follow-up and the poor quality of the data may have affected the results. Nevertheless, our results suggest an association between CVS carried out at less than 10 weeks' gestation and TLRDs which is consistent with the findings of other studies. CVS should not be prepared at less than 10 weeks' gestation until additional evidence is obtained.     

Prenatal sonographic diagnosis of diastematomyelia in a diabetic woman

Diastematomyelia is a structural anomaly which concerns primarily the spine and secondarily the nervous structures contained in it. A case of early prenatal diagnosis (20th week) by ultrasound of diastematomyelia with associated diplomyelia in a diabetic woman is reported. Radiological and pathological examination of the fetus after therapeutic abortion confirmed the diagnosis.