Hamada H, Arinami T, Kubo T, Hamaguchi H, Iwasaki H
Department of Obstetrics and Gynecology, University of Tsukuba, Japan.
Hum Genet. 1993 Jun;91(5):427-32. doi: 10.1007/BF00217766.
To determine the frequency of fetal nucleated cells in maternal peripheral blood during different stages of pregnancy, 50 primigravidas were investigated by determining the frequency of cells with the Y chromosome using fluorescence in situ hybridization (FISH) of Y-specific repetitive sequences of the DYZ1 family. Polymerase chain reaction (PCR) amplifying the same part of the DYZ1 used as the probe in FISH and a single-copy Y-specific fragment was also carried out for genomic DNA from the same samples. Cells with the hybridization signal were detected by FISH at and after 15 weeks of pregnancy in all pregnant women who gave birth to boys. The ratio of cells with the signal to those without the signal ranged from 1 in 144,000 to 1 in 4,000 with a tendency to increase as the pregnancy advanced. The frequency of fetal cells estimated by the PCR experiments was significantly and positively correlated with that found by FISH. The present study suggests that fetal nucleated cells increase in maternal peripheral blood with advancing gestation, from less than 1 in 100,000 nucleated cells in the first trimester to around 1 in 10,000 at term. These frequencies were much lower than those reported by cytological methods.
为了确定孕期不同阶段母体外周血中胎儿有核细胞的频率，通过使用DYZ1家族Y特异性重复序列的荧光原位杂交（FISH）来测定Y染色体细胞的频率，对50例初产妇进行了研究。还对相同样本的基因组DNA进行了聚合酶链反应（PCR），扩增FISH中用作探针的DYZ1的相同部分以及一个单拷贝Y特异性片段。在所有分娩男婴的孕妇中，在怀孕15周及之后通过FISH检测到具有杂交信号的细胞。有信号的细胞与无信号的细胞的比例在144,000分之一至4,000分之一之间，且随着孕期进展有增加的趋势。通过PCR实验估计的胎儿细胞频率与FISH检测到的频率显著正相关。本研究表明，随着孕周增加，母体外周血中的胎儿有核细胞增多，从早孕期每100,000个有核细胞中少于1个增加至足月时约每10,000个中有1个。这些频率远低于细胞学方法报告的频率。
