Explore the dynamic alternation of gene PLAC4 mRNA expression levels in maternal plasma in second trimester for nonivasive detection of trisomy 21

OBJECTIVE: Noninvasive prenatal detection of trisomy 21 (T21) has been achieved by measuring the ratio of two alleles of a single nucleotide polymorphism in circulating placenta specific 4 (PLAC4) mRNA in maternal plasma with a few assays in recent years. Our research is to explore the variations of PLAC4 mRNA expression level in maternal plasma with normal pregnancies in second trimester, which can provide pregnant women deeper insights with suitable detection period for the non-invasive prenatal detection of T21. METHODS: We measured a serial plasma PLAC4 mRNA concentrations weekly from the same 25 singleton normal pregnant women. We recruited maternal plasma samples from 45 singleton pregnant women, comprising of 25 euploid pregnancies (control group; range, 17 to 21 weeks) and 20 T21 pregnancies (T21 group; range, 19 to 24 weeks). With the application of reverse transcription polymerase chain reaction, we achieved an insight of PLAC4 mRNA expression levels in maternal plasma during second trimester with euploid pregnancies. RESULTS: Among the control group, the levels of PLAC4 mRNA expression in the gestation of 17 to 18 weeks were significantly less than those in the gestation of 18 to 21 weeks (P0.05). CONCLUSION: The PLAC4 mRNA showed a higher level of expression in the gestation of 18 to 21 weeks with an euploid pregnancy of pregnant women. We also found that there was no significant difference in plasma PLAC4 mRNA concentration between the normal and the T21 pregnancies in second trimester.

Growth inhibition of human leukemia cell line U937 by all-trans retinoic acid and its mechanism / 中华血液学杂志

<p><b>OBJECTIVE</b>To study the effect of all-trans retinoic acid (ATRA) on U937 cell growth and its mechanism.</p><p><b>METHODS</b>Cell cycle was detected by flow cytometry (FCM), expressions of cell cycle associated protein and the p27 related protein were detected by Western blot. The binding of P27 and Skp2 was detected by immunoprecipitation.</p><p><b>RESULTS</b>FCM displayed that ATRA could inhibit the proliferation of U937 cells. At 72 h on 1 micromol/L ATRA treatment, 72% of the cells were arrested at G0/G1 phase. Western blot displayed that ATRA could decrease the expression of cyclin A, up-regulate the expression of p21 and p27, and down-regulate the expression of p27 related proteins Skp2. p27 could bind with Skp2 in U937 cells as detected by immunoprecipitation.</p><p><b>CONCLUSION</b>ATRA may arrest the proliferation of U937 cells through the reduction of Skp2 expression, and finally the induction of the accumulation of p27.</p>