摘要
确定孕妇外周血中是否存在胎儿细胞以及不同孕期对他的影响。采用套式聚事酶链反应技术，用人Ｙ染色体ＤＮＡ特异基因（ｓｅｘｄｅｔｅｒｍｉｎｉｎｇｒｅｇｉｏｎＹ，ＳＲＹ）作为研究孕妇外周血中胎儿ＤＮＡ的一个基因标本，结果在妊娠早期（８周＾＋３）开始到妊娠晚期（３８周）的孕妇血循环中均能发现源于胎儿的有核细胞，男性胎儿阳性结果的预测值在早、中、晚三个不同孕期分别为３／５，６／８，５／６。
Objective To demonstrate unequivocally the presence and abundance of fetal cells in the blood of pregnant women,with a humen Y chromosome-specific gene as a marker for our investiga- tion.Methods We used a nested-polymerase chain reaction(PCR)assay with oligonucleotide primers flanking sex determining region Y(SRY)single copy Y-specific deoxyribonuleic acid sequences for the detection of a fetal-specific Y-chromosomal sequence from DNA extracted from unsorted maternal pe- ripheral blood.Results It has been shown that fetal uncleated cells can be found in the maternal circu- lation during first trimesters(8_(+3) weeks)to at terms.The predictive values of a positive test for a male fetus were 3/5,6/8,5/6 in the first,second and third trimesters,respectively.Serial dilutions of male umbilical cord blood DNA into female blood DNA indicated that the assay could detect an equivalent of a single male cell(10pg DNA)in 200000(2μg DNA)female cells.This assay exhibited absolute speci- ficity for male.Conclusions Our study demonstrated that fetal uncleated cells indeed exist in maternal peripheral blood,and that fetal DNA appears in the maternal circulation early in the first trimester and continues to be present throughout pregnancy.It can be very valuable for early non-invasive prenatal di- agnosis of inherited disorders.
