Incremental cost-effectiveness of incorporating oestriol evaluation in down syndrome screening programmes

As screening for Down syndrome becomes increasingly sophisticated, it is important to evaluate the newer technologies in terms of their cost-effectiveness. One recent addition to Down syndrome screening programmes is maternal serum unconjugated oestriol (uE₃), especially when used in conjunction with maternal serum α-fetoprotein and human chorionic gonadotropin. Using assumptions used in a California proposal to justify an expanded screening programme for Down syndrome, we calculated both the average and the incremental cost-effectiveness of adding uE₃. Using the base case assumptions, including an $8 fee for the uE₃, the incremental cost-effectiveness of adding uE₃ to the proposed California programme is $119 100 per case detected, a value that compares favourably with other Down syndrome screening programmes. The sensitivity analysis supports this conclusion over a wide range of assumptions. However, because of the uncertainty with some key data, it is still too early to fully support the inclusion of uE₃ in Down syndrome screening programmes.     

Attitudes of women of childbearing age towards prenatal diagnosis in Southeastern France

The objective of this study was to explore women's attitudes towards prenatal diagnosis of trisomy 21 and to examine some of the factors possibly responsible for these attitudes before implementing in real practice serological screening of pregnant women at risk for trisomy 21. We carried out a telephone survey on a representative sample of women who had recently had a normal livebirth delivery in the Marseille district in 1990. The participation rate was 80 per cent and the average age of the mothers was 28-9 years. Among the 514 women interviewed, 78 per cent stated that they would ask for an amniocentesis for a 1 per cent risk of trisomy 21 at their next pregnancy. When adjusting for confounding factors, the decision to have or not to have an amniocentesis was found to depend not only on the women's attitude towards induced abortion, but also on their understanding of the risk involved and on the social context (knowing a handicapped child, discussion with the father). It also depended on the women's age and on what they knew about amniocentesis from the medical point of view. The risk of miscarriage can influence a woman's choice but this objection was not found to affect the women's decisions significantly in our survey. The data showed the existence of a high potential demand for fetal karyotyping.     

Influence of chlorsulfuron herbicide on size of microbial biomass in the soil

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Molecular behavior and interactions with microbes during anaerobic degradation of bio-derived DOM in waste leachate

It is the key to control bio-derived dissolved organic matters (DOM) in order to reduce the effluent concentration of wastewater treatment, especially for waste leachate with high organic contaminants. In the present study, the anaerobic degradation of aerobically stabilized DOM was investigated with DOM substrate isolated through electrodialysis. The degradation of bio-derived DOM was confirmed by reduction of 15% of total organic carbon in 100 days. We characterized the molecular behavior of bio-derived DOM by coupling molecular and biological information analysis. Venn based Sankey diagram of mass features showed the transformation of bio-derived DOM mass features. Occurrence frequency analysis divided mass features into six categories so as to distinguish the fates of intermediate metabolites and persistent compounds. Reactivity continuum model and machine learning technologies realized the semi-quantitative determination on the kinetics of DOM mass features in the form of pseudo-first order, and confirmed the reduction of inert mass features. Furthermore, network analysis statistically establish relationship between DOM mass features and microbes to identify the active microbes that are able to utilize bio-derived DOM. This work confirmed the biological technology is still effective in controlling recalcitrant bio-derived DOM during wastewater treatment.     

生物传感器快速测定BOD在海洋监测中的应用

选用一株耐高渗透压的酵母菌种作为敏感材料可以实现BOD的快速测定。采用海藻酸钙包埋法和聚乙烯醇包埋法两种细胞固定化方法并进行了比较。就聚乙烯醇固定化微生物进行了渗稼压和重金属离子影响的研究。     

含纤维素废水生物水解的应用研究

提取植物或动物纤维所产生的高浓有机废水，含短小纤维、木质素、纤维素、半纤维素、蜡质、果胶及其分解产物(糖、脂肪酸、醇等)，较难生物处理，属含纤维素废水。试验研究和生产应用表明，生物水解对含纤维素废水中高分子有机物，可予分解并提高度水可生化性：在常温、PH约9．5时，水解池污泥浓度达6．5～16．0g/L，容积负荷达2．9kgCOD／m^3．d，COD去除率为24—36％，VFA提高3．9—5．1倍，BOD／COD提高12～16％。分析认为：中温、酸性，纤维素、木素含量低时，水解效果应更好。     

PFU微型生物群落水质鉴别及群落参数变化模式的研究

基于ＰＦＵ微型生物群落参数调查数据，对湖北省汉江两条污染带１１个站 和湖南常德市水系１５个站点所属水质组别进行了综合分析研究。所得典型鉴别函数能够对水质组别作出有效的鉴别，分类函数对站点的水质组别分类正确率达到９６％；群落参数对化学综合污染指数的响应不呈简单的线性关系，群落的变化存在一定模式。     

Ultrasonography in pregnancy and fetal abnormalities: Screening or diagnostic test? IPIMC 1986–1990 register data

The aim of the present study was to assess the sensitivity of ultrasound diagnosis used as a screening test in detecting major congenital anomalies in the prenatal period in a large nation-based multicentre setting. Data from the IPIMC register were collected in the period 1986–1990. One hundred and thirty-five hospitals, located in 17 out of the 20 regions in Italy, participated in the register. Study cases were 3479 infants with major congenital anomalies diagnosed at birth or in the first week of life. Subjects with chromosomal anomalies or multiple defects were excluded. The sensitivity of ultrasound prenatal diagnosis was 49.5 per cent for central nervous system anomalies, 3.8 per cent for congenital heart diseases, 17.1 per cent for gastrointestinal tract defects, 46.6 per cent for abdominal wall defects, 74.8 per cent for urinary tract anomalies, and 22.9 per cent for skeletal abnormalities. The detection rate for diaphragmatic hernia was 24.2 per cent. Overall, only 18 per cent of the defects diagnosed in utero were detected before 24 weeks' gestation. The sensitivity of prenatal diagnosis was 30.1 and 19.0 per cent in the northern, central, and southern regions, respectively. In light of its low sensitivity, ultrasonography as a screening test in the general population should be abandoned, although some improvement in its performance should be expected following adequate training of the ultrasound staff and the use of good technical equipment.     

Carrier screening for cystic fibrosis

A number of different models of CF carrier screening have now been tested in pilot trials. Apart from opportunistic and cascade testing (which are strictly speaking not true forms of screening), the major programmes have been directed either to young adults in primary care or to pregnant women in antenatal clinics. Only in the latter form of screening has sufficient data been collected to allow conclusions to be reached on the optimum mode of delivery. It seems very probable that when CF carrier screening passes into routine service, it will be the antenatal couple model that is used.