Noninvasive prenatal diagnosis of aneuploidy using cell-free nucleic acids in maternal blood: promises and unanswered questions

The discovery of cell-free fetal (cff) DNA and RNA in the maternal circulation has driven developments in noninvasive prenatal diagnosis (NIPD) for the past decade. Detection of paternally derived alleles in cff DNA is becoming well established. Now much interest is focussing on NIPD of fetal chromosomal abnormalities, such as trisomy 21, which is a considerable challenge because this demands accurate quantitative measurements of the amounts of specific cff DNA or cff RNA sequences in maternal blood samples. Emerging strategies for distinguishing and quantifying the fetal nucleic acids in the maternal circulation promise continued development of the field, and pose a number of unanswered questions. Copyright © 2007 John Wiley & Sons, Ltd.     

甲醛对洋葱根尖细胞的遗传毒性效应

将不同浓度(0.1%、1.0%、1.5%和3%)的甲醛溶液作为诱变剂,分别处理洋葱根尖24、36和48 h.通过常规染色体压片技术,观察洋葱根尖细胞有丝分裂现象.研究甲醛对洋葱根尖细胞有丝分裂指数(MI)和染色体畸变的影响,探讨甲醛的遗传毒性和洋葱作为甲醛污染指示植物的可行性.结果表明:不同浓度的甲醛溶液均能使洋葱根尖...     

Treatment of Olive Mill Wastewaters by Pseudomonas putida mt-2: Toxicity Assessment of Untreated and Treated Effluent

Abstract The aim of this work was to examine the performance of Pseudomonas putida mt-2 in treating olive mill wastewater (OMW) effluent after dilution with sterilized water (33%, v/v) to reduce its bactericide effect. P. putida significantly reduced the color and phenolic compounds in OMW by 75% and 66%, respectively. Dissolved chemical oxygen demand and biochemical oxygen demand removals reached 85.3% and 92.5%, respectively. Genotoxicity of OMW, before and after biodegradation with P. putida mt-2, was evaluated in vitro, using SOS chromotest, and in vivo, in mouse bone marrow, by assessing the percentage of cells bearing different chromosome aberrations. Results indicated that OMW showed a significant ability to induce DNA damage, evaluated by SOS and chromosome aberration assay systems. This toxicity was imputed to the presence of phenolic compounds of OMW. However, the toxicity of OMW was significantly reduced after 48?h of aerobic incubation with P. putida mt-2. The present study demonstrates that P...     

The nuchal translucency and the fetal heart: a literature review

In this overview the current knowledge of the relationship between an increased nuchal translucency (NT) measurement and fetal heart structure and function in chromosomally normal fetuses is reviewed. Relevant pathophysiological theories behind the increased NT are discussed. Fetuses with an increased NT have an increased risk for congenital heart disease (CHD) with no particular bias for one form of CHD over another. This risk increases with increasing NT measurement. Although the NT measurement is only a modestly effective screening tool for all CHD when used alone, it may indeed be effective in identifying specific CHD “likely to benefit” from prenatal diagnosis. The combination of an increased NT, tricuspid regurgitation and an abnormal ductus venosus (DV) Doppler flow profile, is a strong marker for CHD. A fetal echocardiogram should be performed at 20 weeks' gestation in fetuses with an NT ≥ 95th percentile but < 99th percentile. When the NT measurement is ≥ 99th percentile, or when tricuspid regurgitation and/or an abnormal DV flow pattern is found along with the increased NT, an earlier echocardiogram is indicated, followed by a repeat scan at around 20 weeks' gestation. The resultant increased demand for early fetal echocardiography and sonographers with this special expertise needs to be planned and provided for. Copyright © 2009 John Wiley & Sons, Ltd.