Factors associated with multiple-pass procedures during chorionic villus sampling: A video analysis

Multiple placental passes during chorionic villus sampling (CVS) increase the risk of fetal loss; however, specific factors that predispose to repeat aspiration have not been delineated. To identify anatomic and technical variables associated with multiple-pass procedures, a detailed review of 205 videotaped CVS procedures (single pass = 163; multiple pass = 42) was performed, blinded to pregnancy outcome. The route of sampling did not influence the need for multiple aspiration attempts (transabdominal—30/ 135; transcervical—12/70), nor was placental location alone discriminatory. However, the combination of a posterior placenta and uterine retroversion was observed more frequently in the multiple-pass cohort (8/42 vs. 9/163; p<0.05). In transabdominal cases, suboptimal needle placement (e.g., perpendicular to the placental long axis) was more common in the initial aspiration of a multiple-pass procedure (21/30 vs. 38/105;p<0.01), while limited penetration of the catheter tip (e.g., just inside the placental edge) characterized a majority of multiple-pass cases in the transcervical subset (7/12 vs. 3/58; p<0.0001). A case-control cohort was constructed to evaluate the impact of these technical variables on sampling efficacy, independent of the influence of uterine position and placental site. In that analysis, suboptimal location and/or orientation of the sampling device remained characteristic of multiple-pass cases. We conclude that further reduction in the frequency of multiple-pass procedures might be achieved by consistent placement of the device tip in the central placental mass. Unlike amniocentesis, where any point of amnion entry will suffice, this technical nuance should be emphasized with CVS to maximize the single-pass success rate.     

Internal circulating fluidized bed incineration system and design algorithm

ＩｎｔｒｏｄｕｃｔｉｏｎＴｈｅｐｒｏｃｅｓｓｏｆｍｕｎｉｃｉｐａｌｓｏｌｉｄｗａｓｔｅ(ＭＳＷ)ｉｓｏｎｅｏｆｔｈｅｍｏｓｔｓｅｒｉｏｕｓｉｓｓｕｅｓｉｎｔｅｒｍｓｏｆｅｎｖｉｒｏｎｍｅｎｔａｌｐｒｏｔｅｃｔｉｏｎ.ＰｒｏｃｅｓｓｉｎｇｏｆＭＳＷｗｉｔｈｏｕｔｆｕｒｔｈｅｒｄｉｓａｓｔｒｏｕｓｃｏｎｔａｍｉｎａｔｉｏｎｃａｎｂｅａｃｈｉｅｖｅｄｏｎｌｙｉｎｍｏｄｅｒｎｉｚｅｄｍｅａｓｕｒｅｓ,ｓｕｃｈａｓｉｎｃｉｎｅｒａｔｉｎｇａｎｄｅｎｅｒｇｙｇｅｎｅｒａｔｉｎｇｃｏｎｃｕｒｒｅｎｔｌｙ(Ｓｈｅｎ…     

Chinese life cycle impact assessment factors

ＩｎｔｒｏｄｕｃｔｉｏｎＬｉｆｅｃｙｃｌｅａｓｓｅｓｓｍｅｎｔ(ＬＣＡ)ｉｓａｎｅｎｖｉｒｏｎｍｅｎｔａｌｍａｎａｇｅｍｅｎｔｔｏｏｌｔｈａｔｉｓｕｓｅｄｔｏｅｘａｍｉｎｅａｎｄｅｖａｌｕａｔｅｔｈｅｅｎｖｉｒｏｎｍｅｎｔａｌｉｍｐａｃｔｓａｓｓｏｃｉａｔｅｄｗｉｔｈｔｈｅｅｘｉｓｔｅｎｃｅｏｆｐｒｏｄｕｃｔｓ(Ｊｅｎｓｅｎ,1998;Ｗｅｉｄｅｍａ,1997;Ｗｅｎｚｅｌ,1997).ＴｈｅｆｏｃｕｓｏｆＬＣＡｉｓｏｎｔｈｅｅｎｔｉｒｅｌｉｆｅｃｙｃｌｅｏｆｔｈｅｐｒｏｄｕｃｔ,ｉ.ｅ.ｆｒｏｍｔｈｅｅｘｔｒａｃｔｉ…     

Population growth, management and environmental degradation in China

Environmental problems in China can be divided into two large classes: pollution and destruction of natural environment. Environmental degradation is particularly serious in areas with rapid population growth. In this paper, some of China's major environmental problems, particularly those concerned with land, forests, and continental waters are introduced in order to see how population growth and management have affected these resources over the past few decades. It is also explained how the Chinese plan to cope and eventually solve these problems.     

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.     

Erythroid-specific antibodies enhance detection of fetal nucleated erythrocytes in maternal blood

Fetal nucleated erythrocytes (NRBC) in maternal blood are a non-invasive source of fetal DNA for prenatal genetic screening. We compared the effectiveness of three monoclonal antibodies for the separation of fetal cells from maternal blood by flow sorting. Mononuclear blood cells from 49 healthy pregnant women were incubated with antibody to CD 71, CD 36, and/or glycophorin A (GPA), employed singly or in combination with each other. These monoclonal antibodies recognize surface antigens on haematopoietic precursor cells. Successful isolation of fetal cells was defined as detection of Y chromosomal sequences in maternal blood from women carrying male fetuses, with absence of Y sequences when female fetuses were carried. Thus, gender prediction accuracy was used as a measure of fetal cell separation. Using anti-CD 71 to isolate fetal cells, gender prediction was 57 per cent correct; with anti-CD 36, it was 88 per cent correct. Anti-GPA, an erythrocyte-specific antigen, used alone or in combination with anti-CD 71 or 36, improved gender prediction to 100 per cent. We conclude that antibody to GPA improves the retrieval of fetal NRBC from maternal blood, permitting genetic analysis by the polymerase chain reaction.     

陆地生态系统的恢复--模拟全球变化所引起的酸性输入减少和海盐输入增加的影响

到2010年<哥德堡议定书>正式实施时,欧洲自20世纪70年代末以来已减少的酸化硫和氮释放量将进一步减少.这里我们论述了通过使用应用于3个大型"清洁雨"实验(即分别在挪威里斯达尔谢伊阿[Risdalsheia],瑞典耶德松[Gardsjon]以及丹麦克洛斯特海泽[Klosterhede]的所谓"屋顶实验")的酸化模型MAGIC讨论恢复酸化陆地生态系统的结果.<哥德堡议定书>的实施将启动通过重建盐基饱和恢复上述3处土壤的进程.恢复率较低,在今后30年中,盐基饱和增加不足5%.气候引发的风暴严重性的加剧将增加海盐输入生态系统的量.这将为土壤提供额外的碱阳离子,并使恢复速度翻一番,同时还将随着沉积的碱阳离子与存储在土壤中的酸性交换导致高海盐输入之后的强酸性脉动.因此,酸化集水区土壤和径流的进一步恢复将取决于酸沉积下降的数量和速率,在近岸系统的情况下,还取决于海盐输入事件的频率和强度.     

镉胁迫下大豆中镉的分布状况及其籽粒品质

溶液培养中0.5μmol·L-1镉胁迫浓度下,大豆表现出轻微受害症状,籽粒减产25 . 7%,而籽粒中粗脂肪和粗蛋白含量变化不大.镉在大豆中的积累分布状况为根>叶>籽>油,比例为32.100:1.690:1.000:0.003.大豆籽粒含镉4.89mg/kg,超过了国家环境标准规定的最高容许量.而大豆粗脂肪中含镉仅0.015mg/kg,远低于国家食品环境卫生标准.豆粕中含镉6.17mg/kg,表明大豆籽粒中的镉主要存在于粗蛋白和淀粉中.