Amniotic fluid alpha-fetoprotein levels and prenatal diagnosis of autosomal trisomies

Pregnancies with fetal trisomy 21 have been associated with low amniotic fluid alpha-fetoprotein levels (AFAFP). This observation led to the suggestion that low AFAFP levels be used as a criterion for completion of a chromosomal analysis in patients who are not otherwise at increased risk for a fetal chromosome abnormality and in whom karyotyping might not have been completed for economic reasons. In order to assess the usefulness of such criteria, we reviewed the AFAFP levels of 90 cases of fetal trisomy 21, 23 cases of trisomy 18, and 10 cases of trisomy 13. These were compared with 2400 control samples with normal chromosome constitution. AFAFP levels were generally lower in pregnancies with trisomy 21, showing a median value of 0·72 MoM. However, 40 per cent of the trisomy 21 samples had AFAFP values greater than 0·8 MoM and 20 per cent were over 1·0 MoM. These data imply that over 50 per cent of Down syndrome cases might have been missed using a cut-off level of 0·70 MoM for completion of chromosome analysis. Using a higher cut-off level will leave only a small percentage of samples unkaryotyped. The distribution of AFP levels in trisomy 13 and 18 is no different from controls; we therefore believe that fetal karyotyping should be completed in every amniotic fluid sample obtained.     

Second-trimester cancer antigen 125 and Down's syndrome

This study explores if assay of cancer antigen 125 (CA 125) in maternal serum might aid the detection of Down's syndrome in the second trimester of pregnancy. CA 125 levels were determined retrospectively in stored maternal serum samples from ten Down's syndrome pregnancies and 78 controls matched for gestational and maternal age. In addition, second-trimester amniotic fluid samples from nine Down's syndrome and 109 unaffected pregnancies were analysed for CA 125. Maternal serum CA 125 values for Down's syndrome pregnancies were lower, with the median being 0.72 multiples of the unaffected population median. The medians for affected and unaffected pregnancies did not differ significantly and there was a considerable overlap in the range of values of cases and controls. The distribution of amniotic fluid CA 125 levels for Down's syndrome pregnancies resembled that for controls. From our present results, we could not find an association between Down's syndrome and second-trimester maternal serum or amniotic fluid CA 125 levels.     

Technical and theoretical considerations in the HLA typing of amniotic fluid cells for prenatal diagnosis and paternity testing

HLA typing of amniotic fluid cells has been used for the prenatal diagnosis of the HLA linked diseases congenital adrenal hyperplasia (21-OH-deficiency (21-OH-def) type) and complement C4 deficiency and it has also been used for the prenatal de termination of paternity. There are, however, technical difficulties in this test associated with the weak expression of some B locus antigens on amniotic fluid cells, and theoretical difficulties related to associations between particular HLA antigens and the 21-OH-def allele. Since certain HLA-B locus antigens are found in significantly increased frequencies among patients with 21-OH-def, there is a relatively high incidence of HLA-B homozygosity among the patients and over 40 percent of the parents of these patients share one or more HLA-B locus antigens. Results of some prenatal HLA typing tests may thus be difficult to interpret, and supplementary tests should be used whenever possible. HLA typing of amniotic cells is, however, the only available procedure for prenatal diagnosis of C4 deficiency and it is the best available procedure for prenatal determination of paternity. A modification of our original procedure allows HLA typing to be performed with increased numbers of HLA typing sera, and sera with optimum reactivity for amniotic fluid cells have now been selected for the definition of most of the more commonly expressed HLA antigens. Although amniotic fluid cells do not express DR antigens, amniotic fluid cells can be typed for the HLA-linked marker glyoxalase I (GLO) and this may be the informative for prenatal diagnosis in some cases.     

Rapid prenatal diagnosis of aneuploidy from uncultured amniotic fluid cells using five-colour fluorescence in situ hybridization

In this paper we describe the use of five-colour fluorescence in situ hybridization for prenatal diagnosis of aneuploidy using uncultured amniotic fluid cells. The analysis is based on ratio mixing of dual-labelled probes and digital imaging for the detection and visualization of five different probes specific for the five target chromosomes, 13, 18, 21, X, and Y. A retrospective blind analysis of 30 coded uncultured amniotic fluid samples correctly detected fetal sex and five trisomy 21 cases. Multicolour fluorescence in situ hybridization used in this way allows rapid and simultaneous detection of the most frequent aneuploidies.     

Prenatal diagnosis of 21-hydroxylase deficiency by rflp analysis of the 21-hydroxylase,complement C4, and HLA class II genes

In 19 pregnancies at risk for 21-hydroxylase deficiency (21OHD) in 18 families with at lea one affected child, prenatal diagnosis was performed by RFLP analysis using the enzymi Taq I and EcoRI and the DNA probes specific for the 21 OH genes, the closely linke complement C4 genes and the highly polymorphic HLA class II genes DRB, DQB, and DPI For fetal DNA analysis either chorionic villi or cultivated amniotic cells were used. In all 1 cases, a clear prenatal diagnosis was possible either with the 21OH probe alone or in mo cases, by combining the results of the different closely linked loci.     

Governing sustainability: a dialogue between Local Agenda 21 and transition management

Since the 1990s, the local level of governance has become increasingly important in addressing the challenge of sustainable development. In this article, we compare two approaches that seek to address sustainability locally, namely Local Agenda 21 and transition management. Discussing both approaches along six dimensions (history, aim, kind of change, governance understanding, process methodologies, and actors), we formulate general insights into the governance of sustainability in cities, towns, and neighbourhoods. This dialogue illustrates two related modes of thinking about sustainability governance. We touch upon the importance of an integrated perspective on sustainability transitions through which sustainability is made meaningful locally in collaborative processes. We suggest that the explicit orientation towards radical change is a precondition for governing sustainability in a way that addresses the root causes of societal challenges. Governing sustainability should address the tensions between aiming for radical change and working with status quo-oriented actors and governing settings. We conclude that governing sustainability should be about finding creative ways for opening spaces for participation, change, and experimentation, that is, for creating alternative ideas, practices, and social relations. These spaces for innovation encourage a reflexive stance on ways of working and one's own roles and attitudes, thereby preparing a fertile terrain for actors to engage in change from different perspectives.     

The promissory note: COP 21 and the Paris Climate Agreement

The 2015 UN climate negotiations in Paris resulted in an inclusive, binding treaty that succeeds the Kyoto Protocol. In contrast to the failure at Copenhagen in 2009, the Paris negotiations are therefore seen as a major diplomatic success that has regenerated faith in the United Nations Framework Convention on Climate Change as a forum for dynamic multilateralism. The Paris Agreement provides a robust framework for ratcheting up efforts to combat global warming. However, the Agreement’s value will remain unclear for some time. The historical path to the Paris accord is outlined, and a preliminary assessment is offered of its key elements and outcomes.     

《21世纪议程》:行动与展望

1992年,联合国环境与发展大会通过了《关于环境与发展的里约热内卢宣言》、《21世纪议程》和《关于森林问题的原则声明》3项重要文件。之后,国际社会为推动"里约精神"的落实做出了积极努力:联合国可持续发展委员会每年举行会议,审议《21世纪议程》的执行情况;许多国家制定了国家和地方层面的《21世纪议程》或可持续发展战略;相关国际组织以可持续发展能力建设为主的活动也十分活跃。人类把发展与环境相协调作为行动准则,各国依据国情制定了促进环境与发展相协调的优先事项,使人类在实现可持续发展的进程中取得了积极进展:全球经济实现了大幅增长,发展中国家在全球经济格局中的地位不断上升;在消除贫困等社会发展方面取得显著效果,全球开始进入城市化时代;全球能源资源供应呈现多元化,资源节约集约利用成效显著。中国在经济发展滞后、贫困现象较严重背景下,承担了全球实施《21世纪议程》的旗舰角色;并依据本国的具体国情,选择性地学习与借鉴,摸索创造出具有自身特色的发展模式和道路,增加了世界可持续发展方式选择的多样性。20年来,尽管各个国家在可持续发展方面采取了积极行动,但是"里约精神"尚未全面转化为行动,在相关国际承诺与公约的履行方面还需付出巨大努力,仍然面临着重大挑战。如:以气候变化为代表的重大全球性环境问题对人类生存构成的直接威胁加大;生态超载背景下的发展空间争夺更趋激烈;全球性民生问题凸显,可持续发展面临的社会风险加大,等等。我们期待:通过"里约+20"大会,使得相关国际制度安排不断形成和完善,可持续发展进一步向全球行动转化;科技创新步伐加快,进一步推动全球向绿色发展转型;加快全球治理体系调整,新兴发展中国家成为全球可持续发展的重要推动力;全球共同努力解决重大资源环境问题,可持续发展领域的国际关系呈现竞争性合作。