Prenatal diagnosis: does it alter outcome?

The prenatal detection of urinary tract anomalies is changing paediatric practice but in many areas the impact on clinical outcome remains difficult to quantify. However it is already apparent that termination of pregnancy has reduced the numbers of infants with lethal pulmonary hypoplasia and renal dsyplasia who would previously have been liveborn but destined to succumb as neonates. Similarly, referrals of major non lethal abnormalities such as bladder exstrophy are declining as parents increasingly opt for termination. Fetuses at greatest risk of early onset postnatal renal failure can now be identified with considerable accuracy on prenatal ultrasound. Termination, prompted by quality of life considerations, could result in reduced numbers of infants and young children requiring end stage renal failure treatment in the first few years of life. Pre natal detection of anomalies such as PUJ obstruction and reflux undoubtedly provides an opportunity to avert functional deterioration and minimise urinary infection. But the proportion of children who genuinely benefit has proved difficult to assess. The prenatal detection of mild dilatation is of doubtful benefit in all but a minority of cases. Clinically significant underlying pathology is rare yet this common prenatal finding often generates disproportionate parental anxiety. Copyright © 2001 John Wiley & Sons, Ltd.     

Antenatal gene tests in low-risk pregnancies: molecular screening for aspartylglucosaminuria (AGU) and infantile neuronal ceroid lipofuscinosis (INCL) in Finland

Approximately one in five subjects in Finland carries some gene defect associated with 30 diseases belonging to the Finnish disease heritage, and about one in 500 children born is affected. Almost all carriers, women and men, are unaware of their condition. Recent advances in molecular medicine have offered the possibility of population-based carrier screening for recessive disorders. We studied acceptance and attitudes to antenatal screening for aspartylglucosaminuria (AGU) and infantile neuronal ceroid lipofuscinosis (INCL). From January 1995 until December 1996 carrier tests were offered at Kuopio City Health Center, free of charge to all pregnant women attending maternity care units. Women found to be carriers of AGU (n=47) or INCL (n=14) underwent detailed genetic counseling, and their male partners were also offered the test. If both partners appeared to be carriers we offered prenatal testing (n=1). No affected fetuses were detected. Attitudes towards the gene test were elicited by means of a questionnaire. Altogether 87% of pregnant women elected to undertake the gene tests. Antenatal screening for gene defects was feasible and well accepted, and it provided an effective way to find carriers of genetic diseases and to incorporate prenatal testing into this process. Copyright © 2001 John Wiley & Sons, Ltd.     

First trimester serum screening for down's syndrome

Screening for Down's Syndrome has been shown to be effective at 10 weeks of pregnancy. A multicentre study (the First trimester serum screening study) has shown that there are two biochemical markers of choice at this time in pregnancy, namely pregnancy associated placental protein A (PAPP-A) and the free β-sub-unit of human chorionic gonadotrophin (free β-hCG). When used together with maternal age these two biochemical markers have an estimated detection rate of 62% and a 5% false-positive rate. The results are consistent with those obtained from a systematic review of the world literature. Other markers are less predictive of Down's syndrome though there is still some uncertainty over the value of dimeric inhibin-A at 10 weeks of pregnancy. Nuchal translucency measurement, from an ultrasound examination performed at about 10 weeks of pregnancy, is associated with Down's syndrome and is emerging as an important potential screening marker. At present there is uncertainty over its quantitative performance and performance when combined with biochemical markers. The resolution of these issues is currently the subject of active research. Ten week screening for Down's syndrome is an advance that is now technically possible though there is still insufficient information to justify its use in routine screening practice.     

Cadmium in aquatic microcosms: Implications for screening the ecological effects of toxic substances

A two-phase set of experiments was conducted to address some of the problems inherent in ecological screening of toxic substances in aquatic microcosms. Phase I was a 4×4 factorial experiment dealing with the interactive effects of cadmium and nutrients in static microcosms. Phase II was a 2×4 factorial experiment using flowthrough microcosms to study temporal aspects of system behavior in response to nutrient loading and chronic versus acute cadmium perturbations. Nutrient enrichment resulted in increased biomass and metabolic activity in both static and flowthrough microcosms. Cadmium treatments generally resulted in a decrease in abundance of grazing crustaceans and a subsequent increase in community respiration, suggesting a change in community structure from a grazing to a detritus food chain. Of the variables measured, community metabolism, community composition, and output/input ratios of nitrate-nitrogen were the most useful indicators of system response to cadmium. Nutrient enrichment significantly influenced cadmium effects with respect to most of the variables measured; high levels of enrichment reduced the effects of cadmium. For screening the ecological effects of toxic chemicals, a series of experiments is proposed, including 1) relatively simple static microcosms, 2) flow through microcosms, and 3) more detailed but selective studies in microcosms derived from specific ecosystems. Each step yields increasingly more information and serves as a guide for subsequent experiments; in addition, each step more closely approximates natural ecosystems.     

水环境红线划定技术与管控措施初探

国家水环境红线是国家环境质量安全底线这一生态保护红线体系的三大要素之一,是国家生态保护红线中非常重要的组成部分.本文系统总结了国家水环境红线的概念、内涵和特征,重点阐述了国家水环境红线的划定流程和技术方法,并从“质量-排放-风险”全面介绍了国家水环境红线的管控措施,提出了加快推进国家水环境红线管理的3点建议.     

工业场地再利用适宜性评价研究

土地是生态环境的重要组成部分,也是人类赖以生存的主要资源之一。随着城市规模的不断扩大,越来越多的工业企业搬离老城区,如何实现工业搬迁场地的安全再利用已成为制约土地资源再利用的关键因素。以泰安市某个工业搬迁场地为例,以北京市《场地环境评价导则》(DB 11/T 656-2009)中通用土壤筛选值为评价标准,通过对场地土壤环境质量进行调查与监测,对该场地能否再利用进行适宜性评价,以保证土地资源的安全再利用,为土地资源管理提供合理依据。     

家具行业挥发性有机物治理成本及排污权交易价格估算

佛山市顺德区工业VOCs污染问题突出,以中小企业为主的家具行业排放是第二大来源(17%),因此,顺德区率先在广东省开展了家具行业VOCs排污权交易试点工作.本文以区内木质家具行业为例,研究了排污权交易定价方法,得到VOCs平均污染治理成本(5363.26元·t~(-1)·a~(-1))并将其作为排污权交易的初始价格,之后运用多级模糊综合评价法计算的地区调整系数(γ=1.47)进行修正,得到最终参考交易价格(7883.99元·t~(-1)·a~(-1)).该价格与2016年交易底价(8000元·t~(-1)·a~(-1))偏差较小(1.45%).本文还开发了内置核心算法的挥发性有机物排污权交易辅助定价工具,综合利用数据库中企业基本信息、挥发性有机物排放数据等,为排污权交易定价提供辅助决策服务.     

一株耐盐废水降解菌株的分离与特性

从皂素废水生化处理系统中活性污泥中分离筛选出1株耐高氯离子(CaCl)2的皂素废水降解菌S616,并对其进行菌种鉴定和降解性能研究。综合16SrDNA测序结果和菌株的生理生化实验结果确定细菌S616为坚强芽孢杆菌;以皂素废水(COD6230mg/L,[Cl-]=20000～30000mg/L)为例,研究其降解能力:发现该菌株能有效去除皂素废水中COD的能力,能在3d之内去除废水中的COD为70%以上(实验条件:恒温35℃,140r/min振荡,pH=7.5～8.0)。     

曝气生物滤池处理生物质废水及降解菌分析

生物质污水含有大量的纤维素、半纤维素、淀粉、糖类、有机酸、蛋白质,COD值很高,严重污染环境,并造成生物质资源浪费.采用曝气生物滤池(BAF) 处理生物质污水,通过分析污水化学需氧量(COD),总氮(TN)的去除率表征该系统对高COD生物质污水的处理效果.结果表明,水力停留时间(HRT)为10 h,进水运行10 h后,出水平均COD为74.90 mg/Ｌ,总氮(TN)为1.21 mg/Ｌ,去除率分别达到95.7%与94.5%,均达到国家污水综合排放标准(GB 8978-1996)第二类污染物最高允许排放浓度的一级标准.系统运行稳定后,利用扫描电镜(SEM)观察载体的表面微生物的挂膜情况,并结合微生物分离、单菌处理效果评价、16S rDNA鉴定技术对系统内去除COD的优势菌群进行了分析,优势菌群为假单孢菌属、不动杆菌属、寡养单胞菌属、红球菌属、微杆菌属.