The time of appearance and disappearance of fetal DNA from the maternal circulation

A single copy Y-chromosome DNA sequence was amplified using the polymerase chain reaction (PCR) from the peripheral blood of 30 women who had achieved a pregnancy through an in vitro fertilization (IVF) programme. The time of conception was known precisely and was confirmed by serial ultrasound scans. Conceptions were dated as the number of weeks after fertilization plus 2, to give a time equivalent to the obstetric menstrual dating of the pregnancy (LMP). Y-chromosome-specific DNA was detected in all pregnancies with a male fetus (18/30). The earliest detection was at 4 weeks and 5 days, and the latest at 7 weeks and 1 day. Y-chromosome-specific sequences were no longer detected in any of the male pregnancies 8 weeks after delivery. No Y-chromosome sequences were detected in any of the pregnancies where only female babies were delivered. This demonstrates that fetal DNA appears in the maternal circulation early in the first trimester, that it can be identified in all pregnancies tested by 7 weeks, that it continues to be present throughout pregnancy, and that it has been cleared from the maternal circulation 2 months after parturition. Early non-invasive prenatal diagnosis for aneuploidies and inherited disorders will be possible in all pregnancies if fetal cells can be isolated free from maternal contamination (or identified accurately in the presence of maternal cells) without problems of contamination from previous pregnancies.     

Fetal curarization for prenatal magnetic resonance imaging

Fetal magnetic resonance (MR) imaging was performed at 33 weeks of gestation for investigation of a posterior fossa abnormality found at ultrasound screening. Fetal movements were abolished by vecuronium injected under ultrasound guidance into the umbilical vein. MR images showed atrophy of the left cerebellar lobe with cisternal dilatation. These were confirmed postnatally by CT scan.     

Longitudinal assessment of blood flow velocity waveforms in the healthy human fetus

A longitudinal study was carried out on 30 healthy fetuses in order to assess the modifications of fetal blood flow throughout pregnancy. The pulsatility index was evaluated at two-week intervals by means of pulsed Doppler equipment. In the umbilical artery measurements were performed from 20 weeks onwards, whereas in the descending aorta and internal carotid artery analysis started from 26 weeks onwards. A decrease of the pulsatility index in umbilical artery and in the ratio between the pulsatility indexes in umbilical artery and internal carotid artery was found over the second half of pregnancy.     

Abnormal immunological development in fetuses with trisomy 18

Flow cytometry was used to enumerate the lymphocyte subpopulations in fetal blood obtained by cordocentesis from eight trisomy 18 fetuses at 20–36 weeks' gestation. Compared with values in chromosomally normal fetuses, in trisomy 18 the mean T- and natural killer (NK) cell counts were significantly lower (t= − 7·63, P<0·001 and t= − 3·58, P<0·01, respectively); the mean B-cell count was not significantly different (t= − 1·32). These findings demonstrate that in trisomy 18 there is abnormal intrauterine development of the immune system.     

Antenatal thrombocytopenia in three patients with TAR (thrombocytopenia with absent radii) syndrome

Three fetuses with TAR (thrombocytopenia with absent radii) or TAR variant syndrome were found to be thrombocytopenic during the third trimester of the pregnancy. These findings indicate that fetal blood sampling, besides ultrasonography, skeletal radiographs, or even fetoscopy, may indeed contribute to the prenatal diagnosis of TAR syndrome, and thus may help in differentiating TAR syndrome from other syndromes with malformations of the upper limbs.     

46,XY/47,XY,+ 17p+ mosaicism in amniocytes associated with fetal abnormalities despite normal fetal blood karyotype

46,XY/47,XY, + 17p + mosaicism was found in two primary amniotic fluid cultures (AFCs). Fetal blood karyotype was normal, but ultrasonography revealed Dandy-Walker malformation and bilateral choroid plexus cysts. Following termination of pregnancy, fetal examination revealed post-axial polydactyly and neuroblastoma-in-situ affecting both adrenals in addition to the cerebellar abnormalities. Mosaicism for the aberrant cell line was confirmed in all fetal tissues sampled and in the placenta.     

Prenatal exclusion of late infantile metachromatic leucodystrophy in a late-presenting pregnancy by assay of fetal leucocytes

Metachromatic leucodystrophy was excluded in a fetus at risk, by assay of fetal blood collected at fetoscopy. Isolated fetal leucocytes were shown to have activities of arylsulphatase A and cerebroside sulphatase in the heterozygous range. The prediction was confirmed in the newborn.     

用SPE法萃取,GC／NPD检测全血中氯氮平药物

本文报道了用固相萃取技术（ＳＰＥ）富集分离全血中的氯氮平药物，采用气相色谱氮磷检测器（ＧＣ／ＮＰＤ）分析方法凤ＳＫＦ５２５Ａ为内标物，在１ｍｌ全血中加入２．０μｇ药物，回收率为９０．０％，ＲＳＤ为７．９５％，血中最低检出浓度为５８ｎｇ．ｍｌ＾－１，该方法具有简单、快速、准确、１灵敏的优点。     

新形势下如何加强高校领导班子思想政治建设的思考

本文着重阐述了在新形势下加强高校领导班子思想政治建设,必须切实抓好党的基本理论、路线、方针、政治纪律、民主集中制、团结、群众路线、观点、廉洁自律等六个方面的教育,这样才能全面提高领导班子的整体素质和整本功能。     

Male residence and the patterning of serum testosterone in vervet monkeys (<Emphasis Type="Italic">Cercopithecus aethiops</Emphasis>)

This study investigated hormonal and demographic processes underlying unimale and multimale mating systems in primates. Reproductive skew and challenge models of male competition provide conflicting predictions of the relationship of male residence to group composition and androgen regulation. These predictions were tested using endocrine and socioecological data from Kenyan vervet monkeys (Cercopithecus aethiops). Serum samples from 57 adult male monkeys, drawn from 19 separate groups and 4 populations, were assayed for testosterone by radioimmunoassay. Male ability to respond to conspecific challenge was assessed by their testosterone response to the capture protocol.Analyses showed that reproductive skew models were useful predictors of intergroup and interpopulation variation in male residence and T profiles. The Limited Control model of male residence was supported by positive correlations of the number of males per group with the number of females without dependent offspring, demonstrating that monopolization potential was a key determinant of male residence. Testosterone concentrations under conditions that elevated serum levels were positively correlated with infanticide risk, supporting the Concession model. Population comparisons provided evidence for increased T responsiveness where groups were predominantly unimale. Unimale populations were from sites with higher rainfall, suggesting that ecological factors contributed to population differences in male residence and T regulation.For species name, we follow the 2000 taxonomy of the IUCN/SSC Primate Specialist Groups workshop (Grubb et al. 2003)