Preliminary study on the clinical value of noninvasive prenatal testing of fetal chromosomal copy number variations / 中国实用妇科与产科杂志

OBJECTIVE: To explore the clinical value of non-invasive prenatal testing(NIPT)for screening fetal chromosomal copy number variations(CNVs) and microdeletion/microduplication syndromes(MDs).METHODS: Retrospective analysis was made in the 10 005 women who received NIPT during the first trimester(15-20+ 6 weeks)from January,2012 to July,2017,at First People's Hospital of Yunnan Province,Department of Genetic Diagnosis Center.Among them 32 pregnant women were indicated fetal CNVs,25 of 32 pregnant women selected interventional prenatal diagnosis.Statistical analysis was made on the amniotic fluid/cord blood chromosome G band karyotype and high-throughput sequencing(NGS)genome copy number analysis was made,and relevant CNVs were searched and analyzed in the corresponding database;the consistency of CNVs found in NIPT with interventional prenatal diagnosis was statistically analyzed.RESULTS: During the second trimester(15-20+ 6 weeks),in the 10 005 pregnant women who received NIPT testing 32 cases were shown to have high risks of fetal CNVs,and the screening positive rate was 0.32%(32/10 005).In 25 high risk pregnant women who accepted invasive prenatal diagnosis via informed choice,14 women wereconfirmed as fetal CNVs,the positive predictive value(PPV)of NIPT being 56%(14/25),including 9 cases of microdeletion and 5 cases of microduplication.The sizes were between 587.75 kb and 36.05 Mb.The size and the start and end positions of CNVs found by NIPT were similar to those of fetal DNA samples detected by NGS.Among 14 cases of fetal CNVs,11 cases were identified as MDs,3 cases as unknown clinical significance.In 11 cases of MDs,8 cases were observed fetal chromosome structure abnormalities by karyotype analysis,10 cases were confirmed as de novo abbreviations,and 2 cases as originated from paternal same MD.After genetic counseling,10 pregnant women in 11 cases of MDs chose informed terminations,and one case chose continuing pregnancy.CONCLUSION: As a high-precision screening method,NIPT is expected to be an effective mean to screen for fetal CNVs,which can be used to detect highrisk chromosome microdeletion and microduplication CNVs of larger segments.High risk cases of fetal CNVs found by NIPT require invasive prenatal diagnosis for validation.

Enzymatic synthesis of monoglycerides in microaqueous media by using lipase from Pseudomonus fluorescens / 生物工程学报

Enzymatic synthesis of monoglycerides by glycerolysis of oil and fats in microaqueous solvent-free media was investigated by using lipase from pseudomonus fluorescens (PFL). Initial eutectic point(IEP) was substituted for melt point of oil and fats in Critical Temperature Theory. By investigating the glycerolysis under different IEP, it is showed that there is a relationship between composition of the oils and the yield of monoglycerides: Y = -0.0006 X3 + 0.0592 X2 - 0.8909 X + 26.753(13% < X < 76.5%), here X is the contents(W/W) of saturated fatty acid residue (C16 + C18) in the oils, Y is the yield of monoglycerides at 40 degrees C. The optimum isothermal reaction conditions for a system which IEP is 40 degrees C are: 40 degrees C, 3%-4.5% (W/W) water in glycerol, dosage of lipase is 500 u/g oil when the mole ratio of glycerol to oil is 2.5:1. The highest yield of monoglycerides is 81.4% in 48 h by means of programming temperature reaction.

Synthesis of partial glycerol caprates by using lipase in nonaqueous media / 生物工程学报

Enzymatic esterification by reacting caparic acid with glycerol in solvent-free system was studied. Lipases from Pseudomonas fluoresces(PFL), Mucor miehei(MML) and Candida antarictica(CAL) possessed good catalytic activity. The optimal reaction conditions to convert capric acid with CAL are: 60 degrees C, 20-100 u of CAL per gram capric acid, 12% (W/W) of initial water content in glycerol. CAL does not express its 1,3-specificity in final product. Mechanical fraying denatured CAL partly. 96.4% of catalytic activity of CAL recovered after 5 batches of reaction. Extraction with sodium carbonate solution can decrease acid value of product from 9.8 mg KOH/g to 0.68 mg KOH/g. Applying the enzymatic esterification in open system, under vacuum or dehydrating with molecular sieves all dehydrate effectively. Molar ratio of reactants does not influence the total conversion of capric acid but influences the yield of monoglyceride. With certain protocols, the reaction period could be shortened dramatically; conversion of capric acid reached 96.9% in 5 h.