A risk model of prenatal screening markers in first trimester for predicting hypertensive disorders of pregnancy.

BACKGROUND: We aimed to construct a risk model to assess the diagnostic value of predicting hypertensive disorders of pregnancy (HDPs) by screening a range of prenatal markers, including pregnancy-associated plasma protein A (PAPP-A), free beta-human chorionic gonadotropin (free ß-hCG), and fetal nuchal translucency (NT). METHOD: We analyzed 902 women, classified into four groups: healthy gravidas (n = 680, controls), gravidas with gestational hypertension (n = 61; GH), gravidas with preeclampsia (n = 90; PE), and gravidas with severe preeclampsia (n = 71, SPE). We then compared the multiple of median (MoM) of PAPP-A, free ß-hCG, and NT. A risk model was constructed and receiver operating characteristic curve (ROC) analysis was used to diagnose HDPs. RESULTS: Levels of PAPP-A and free ß-hCG levels in the GH, PE, and SPE groups were significantly lower than those in the control group (χ 2 = 7.522, P = 0.001; χ 2 = 17.775, P < 0.001). NT did not differ significantly when compared across all four groups (χ 2 = 1.592, P > 0.05). When the cut-off values for PAPP-A and free ß-hCG were 0.795 MoM and 1.185 MoM, the corresponding sensitivities and specificities were 0.514 and 0.635, and 0.734 and 0.450, respectively. The best risk calculation featured PAPP-A, free ß-hCG, and NT; this model exhibited the highest diagnostic value in the SPE group, followed by the GH group and then the PE group. CONCLUSION: The use of prenatal screening markers during early pregnancy can identify fetal aneuploidy and can also predict HDPs. The development of innovative screening strategies for gravidas and the targeted prevention of HDPs in high-risk gravidas are essential for perinatal care and early intervention, thus creating significant opportunities for predictive and preventive personalized medicine. In our study, we found that the combination of a series of prenatal screening markers in early pregnancy is better than a single marker; our data clearly demonstrate the diagnostic value of combining PAPP-A, free ß-hCG, and NT for patients with SPE.

Significance of data analysis in the quality control of prenatal screening for Down syndrome.

Dual detection of α-fetoprotein (AFP) and free ß-human chorionic gonadotropin (ß-HCG) is a common screening method for Down syndrome in the second trimester and its efficacy is assessed by false-positive rate (FPR). The present study aimed to investigate the effects of the bias in median multiple of the median (mMoM) values of AFP and free ß-HCG on FPR. The bias in mMoM values of AFP and free ß-HCG and the bias in mMoM values under different gestational ages and weight groups were analyzed. Median equations were adjusted, and medians in LifeCycle software were replaced by local medians. Following two adjustments of the median equations, all indices including FPR, mMoM values of markers and mMoM values under different gestational ages and weight groups generally reached an ideal state. In conclusion, abnormal bias in mMoM values may prompt aberrant application of median equations, and regular monitoring of these indicators may be important for quality control in prenatal screening.

Plant siRNAs from introns mediate DNA methylation of host genes.

Small RNAs (sRNAs), largely known as microRNAs (miRNAs) and short interfering RNAs (siRNAs), emerged as the critical components of genetic and epigenetic regulation in eukaryotic genomes. In animals, a sizable portion of miRNAs reside within the introns of protein-coding genes, designated as mirtron genes. Recently, high-throughput sequencing (HTS) revealed a huge amount of sRNAs that derived from introns in plants, such as the monocot rice (Oryza sativa). However, the biogenesis and the biological functions of this kind of sRNAs remain elusive. Here, we performed a genome-scale survey of intron-derived sRNAs in rice based on HTS data. Several introns were found to have great potential to form internal hairpin structures, and the short hairpins could generate miRNAs while the larger ones could produce siRNAs. Furthermore, 22 introns, termed "sirtrons," were identified from the rice protein-coding genes. The single-stranded sirtrons produced a diverse set of siRNAs from long hairpin structures. These sirtron-derived siRNAs are dominantly 21 nt, 22 nt, and 24 nt in length, whose production relied on DCL4, DCL2, and DCL3, respectively. We also observed a strong tendency for the sirtron-derived siRNAs to be coexpressed with their host genes. Finally, the 24-nt siRNAs incorporated with Argonaute 4 (AGO4) could direct DNA methylation on their host genes. In this regard, homeostatic self-regulation between intron-derived siRNAs and their host genes was proposed.

CloneAssistant 1.0: a stand-alone software for automated cloning primer design.

"CloneAssistant 1.0" is a stand-alone software compatible with the current Windows operating systems, which can automatically design cloning primers with full consideration of the sequence information of vectors and genes, cloning strategies, the principles of primer design, reading frames, position effects, and enzymatic reaction conditions for users. Five internal XML (extensible markup language) databases [restriction enzymes, plasmids, universal buffers, PCR (polymerase chain reaction) protection bases, and an MCS (multiple cloning site) double digest interference database] were established to serve as the basic support for "CloneAssistant 1.0". The primer pairs designed are sorted according to the difficulty of the follow-up experiments. Once a primer pair is selected by the user, detailed experimental guidance for this primer pair will be provided. In addition, "CloneAssistant 1.0" can be used for restriction map analysis, ORF (open reading frame) finding, sequence alignment and complementary analysis, translation, restriction enzyme and universal buffer queries, and isocaudamer analysis. "CloneAssistant 1.0" makes gene clone design much easier, and it can be freely downloaded from http://bis.zju.edu.cn/clone.

Epigenetic performers in plants.

Epigenetic research is at the forefront of plant biology and molecular genetics. Studies on higher plants underscore the significant role played by epigenetics in both plant development and stress response. Relatively recent advances in analytical methodology have allowed for a significant expansion of what is known about genome-wide mapping of DNA methylation and histone modifications. In this review, we explore the different modification patterns in plant epigenetics, and the key factors involved in the epigenetic process, in order to illustrate various putative mechanisms. Experimental technology to exploit these modifications, and proposed focus areas for future plant epigenetic research, are also presented.