Prenatal diagnosis of fetal sex by molecular analysis of maternal plasma after 8 weeks of gestation

Prenatal diagnosis of fetal sex is usually performed by invasive methods such as sampling through amniocentesis or chorionic villus sampling. One potential non-invasive approach involves analysis of cell-free fetal DNA in maternal plasma or serum. The objective of our study was to investigate the feasibility of using fetal DNA in maternal plasma for prenatal diagnosis of fetal sex. In this experimental study, a nested polymerase chain reaction [PCR] techniques was developed for fetal SRY gene identification using cell-free fetal DNA in maternal plasma. Peripheral blood samples were obtained from 32 pregnant women at the gestational period from 8 to 13 weeks and cell-free DNA was extracted by the phenol/chloroform method from plasma. The nested PCR was carried out to amplify the fragment of SRY gene by two sets of PCR primer pairs. Analysis was then performed on the PCR product. Specifically, the presence of Y-chromosome sequences in maternal blood plasma indicated that the fetus is male, whereas lack of signal will indicate that the fetus is female. Among the 32 pregnant women, SRY sequences were detected in 14 plasma samples after nested PCR amplification, while the 18 women bearing female fetuses had the negative results. The sensitivity of this technique was 87.5%. The phenol/chloroform extraction of fetal DNA in maternal plasma is an effective and simple method, and the nested PCR amplification of SRY sequence is a convenient and low-cost approach for the non-invasive early prenatal diagnosis of fetal sex

Comparative study of tissue culture and ELISA methods for cytomegalovirus infection diagnosis in abortions

Primary infection of cytomegalovirus especially in first and second trimester of pregnancy causes severe tissue injury and congenital abnormalities. Infection in third trimester of pregnancy has a higher chance of transmission but less tissue injury. Elisa method is a simple test for diagnosis of serum antibody but blood lymphocytes culture is a better and more specific diagnostic method than Elisa. In this study we compared Elisa and tissue culture methods for the diagnosis of congenital cytomegalovirus infections. In this study 5 ml of blood obtained from mothers who aborted their fetuses. Then serum antibody was titrated by ELISA method. Moreover, 5ml of citrated blood with 2 ml of Ficohl hypaque centrifuged in 3000 g and buffy coat layer of leukocytes was separated. These cells cultured in MRC5 fibroblast cell line and were assessed for intracellular inclusion bodies after 72 hours. Positive samples were selected and tested for nucleic acids of cytomegalovirus with PCR method. In this study, 118 cases of abortion were included. In tissue culture method, 6 samples [7.2%] had intracellular inclusion body. Of these samples only 4 had cytomegalovirus nucleic acid by PCR method. Two cases showed increasing anti-cytomegalovirus IgM with ELISA but they were negative by tissue culture method. In general, 6 cases [7.2%] of cytomegalovirus infection were diagnosed. ELISA and tissue culture methods should be performed together. Cytomegalovirus infection has not likely any relation with habitual abortion and is seen in first time abortions preferably