Hyodo Maki, Samura Osamu, Fujito Naoya, Tanigawa Miho, Miyoshi Hiroshi, Fujiwra Hisaya, Miharu Norio, Kudo Yoshiki
Department of Obstetrics and Gynecology, Graduate School of Biomedical Sciences, Hiroshima University, 1-2-3 Kasumi, Hiroshima, Japan.
Prenat Diagn. 2007 Aug;27(8):717-21. doi: 10.1002/pd.1765.
We have determined the number of fetal nucleated cells and the concentration of cell-free fetal DNA in parallel in the same maternal blood samples either before or after delivery, and studied the relationship between these two.
Venous blood samples were taken at four points around delivery from ten women who had singleton male fetus with informed consent. The number of fetal nucleated cells having a Y chromosome specific signal treated by two-color fluorescence in situ hybridization technique was counted using maternal whole blood. The concentration of sex-determining region Y gene sequence was determined using real-time quantitative PCR.
The number of fetal nucleated cells decreased after delivery, and some fetal cells were present 1 month after delivery. While cell-free fetal DNA decreased rapidly after delivery and became undetectable 1 day after delivery in eight out of ten cases. The number of fetal nucleated cells did not correlate with the concentration of cell-free fetal DNA in maternal circulation.
The present study demonstrates that cell-free fetal DNA disappears very rapidly after delivery and fetal nucleated cells remain longer in maternal circulation, and that there is no correlation between these two either before or after delivery.
我们在分娩前或分娩后的同一孕妇血样中，同时测定了胎儿有核细胞数量和游离胎儿DNA浓度，并研究了两者之间的关系。
在获得知情同意后，从10名单胎男性胎儿的孕妇中，在分娩前后的四个时间点采集静脉血样。使用孕妇全血，通过双色荧光原位杂交技术对具有Y染色体特异性信号的胎儿有核细胞进行计数。使用实时定量PCR测定性别决定区Y基因序列的浓度。
分娩后胎儿有核细胞数量减少，产后1个月仍有一些胎儿细胞存在。而游离胎儿DNA在分娩后迅速减少，10例中有8例在分娩后1天就检测不到了。胎儿有核细胞数量与孕妇循环中游离胎儿DNA浓度无关。
本研究表明，游离胎儿DNA在分娩后消失非常迅速，而胎儿有核细胞在孕妇循环中留存时间更长，且分娩前后两者之间均无相关性。
