利用孕妇外周血浆小片段游离胎儿DNA检测Y染色体性别决定区基因

目的探索从孕妇外周血浆中提取小片段游离胎儿DNA（cffDNA）提高检测胎儿Y染色体性别决定区（SRY）基因准确率的方法,评估利用小片段cffDNA进行无创性产前诊断可行性。方法收集117例孕妇外周血,利用柱吸收方法提取其血浆cffDNA,经琼脂糖凝胶电泳分离富集小片段cffDNA,使用二重PCR反应（dulex-PCR）检测SRY基因和磷酸甘油醛脱氢酶（GAPDH）基因。结果来源于66例孕男胎孕妇血浆标本小片段cffDNA均检出SRY和GAPDH基因,来源于50例孕女胎孕妇血浆标本小片段cffDNA仅检出GAPDH基因。与绒毛/羊水标本检测结果相符。特异性和敏感性均为100%。结论利用琼脂糖凝胶电泳,切胶回收,可选择性富集孕妇外周血小片段cffDNA,相对提高胎儿DNA水平,结合二重PCR扩增SRY基因技术可用于无创性产前性连锁遗传疾病和单基因突变疾病产前诊断。     

高通量测序联合染色体核型检测筛查高龄孕妇胎儿发育畸形的实践研究

目的 分析高通量测序联合染色体核型检测对高龄孕妇胎儿发育畸形的筛查效能.方法 回顾性分析2018年4月至2019年10月解放军联勤保障部队第901医院收治的102例有胎儿发育畸形高危因素的高龄孕妇的临床资料,患者均接受高通量测序、染色体核型检查.采用"四格表"记录检测结果,并评价不同方法筛查高龄孕妇胎儿发育畸形的价值,...     

Early detection of cell-free fetal DNA in maternal plasma

OBJECTIVES: We aimed to establish the earliest gestational age at which fetal DNA in maternal plasma could be detected and whether this was reliable at 12-13 weeks' gestation. STUDY DESIGN: A prospective observational cohort study of 32 pregnancies either after IVF or before prenatal diagnosis by CVS. Maternal blood was taken and RT-PCR was carried out to detect the multi-copy Y chromosome associated DSY14 gene. The end point was gender as assessed at delivery or on karyotype. RESULTS: Y signal was obtained as early as 14 days post conception (4 weeks' gestation) and has a good prediction rate by 12 weeks' gestation. CONCLUSION: Free fetal DNA allows very early prediction of fetal sex in some cases and could be useful for clinical use for X-linked conditions by the end of the first trimester.     

Preserved fetal plasma amino acid concentrations in the presence of maternal hypoaminoacidemia

The effects on the conceptus of persistently decreased maternal plasma amino acid concentrations were studied in pregnant rats by the infusion of glucagon (0.21 mg/day) to the mother from day 14 to 20 of gestation with a subcutaneous, osmotically driven minipump. Controls received diluent. The experimental animals either had normal caloric intake and weight gain, or diminished caloric intake with no weight gain. Both experimental groups exhibited a decrease in plasma total amino acid concentration of approximately 50%. Maternal plasma glucose and insulin concentrations were unaffected except for slight decreases in the low weight gain group. At cesarean section on day 20, fetal weight was unaffected in the normal weight gain group, while the low weight gain animals exhibited intrauterine growth retardation. Fetal plasma glucose and insulin concentrations were unaffected. Despite the marked decrease in maternal plasma total amino acid concentration, fetal plasma total amino acid concentration was unaffected. Individual plasma amino acid concentrations in the normal weight gain mothers and fetuses revealed a spectrum of changes. Some maternal amino acids were decreased by more than 60% (alpha-aminobutyric acid, asparagine, threonine, glutamine, alanine) while others were unaffected (tyrosine, tryptophan, phenylalanine, histidine). In general, amino acids that were decreased in the mother exhibited no change or a lesser decrease in fetal plasma concentration, while those that were unaffected in the mothers showed increased fetal concentrations. Fetuses from the low weight gain mothers had plasma amino acid profiles that were similar to those of the normal weight gain mothers.(ABSTRACT TRUNCATED AT 250 WORDS)     

The actions of vasoactive drugs on fetal and maternal plasma renin activity.

The association between fetal arterial pressure and fetal plasma renin activity (PRA) was studied in 30 fetal lambs prepared acutely, but studied in utero. There was a negative correlation between resting fetal arterial pressure and resting fetal PRA (p less than 0.05). Fetal hypotension caused by intravenous infusion of sodium nitroprusside was associated with increases in fetal PRA. Fetal hypertension caused by intravenous infusion of phenylephrine to the fetus was associated with a decrease in fetal PRA. Maternal hypotension caused by infusion of sodium nitroprusside to the mother, and maternal hypertension caused by maternal infusion of phenylephrine caused an increase in fetal blood pressure and a fall in fetal PRA. It is concluded that the hypertensive response of the fetus to these changes in maternal blood pressure was not initiated by the fetal renin-angiotensin system. Isoprenaline caused a rise in fetal PRA. In 11 of 28 infusions this increase in fetal PRA occurred even though diastolic pressure was increased. It is concluded that there is a beta-adrenergic receptor in the fetal kidney which can release renin. The increase in fetal PRA with intravenous isoprenaline was blocked by propanolol. Infusions of adrenaline were not associated with increases in fetal PRA.     

Plasma calcium control in the rat fetus. III. Influence of alterations in maternal plasma calcium on fetal plasma calcium level

Acute maternal alterations in plasma calcium were used as an indirect mean to study the placental transfer of calcium in thyroparathyroidectomized (TPTX) pregnant rats. Calcium infusions to normal or TPTX females showed in both cases a saturation mechanism reflected on fetal plasma calcium. With TPTX mothers saturation curves of the fetal plasma calcium were similar whether fetuses were decapitated (deprived of brain, hypophysis, and thyroparathyroid complex) or intact. Increments in fetal plasma calcium were 4-fold higher in TPTX mothers (approximately 2.5 mg/dl), and 2-fold higher in thyroidectomized (TX) mothers (approximately 0.5 mg/dl). From the whole results, it appeared that increments in fetal plasma calcium secondary to maternal calcium infusion were probably related to the basal plasma calcium in the fetus, and not to the hormonal deficiency of the mother.     

Homocysteine, cysteine, and related metabolites in maternal and fetal plasma in preeclampsia

Homocysteine is associated with endothelial dysfunction and cardiovascular disease, and elevated concentrations of homocysteine have been found in preeclampsia. The purpose of this study was to investigate maternal and fetal concentrations of total homocysteine and related metabolites (including cysteine, choline, and betaine), and possible associations with infant birth weight. Women with preeclampsia (n=47) and controls (n=51), who underwent cesarean section, were included. Maternal plasma, umbilical vein, and artery plasma were analyzed. Median concentrations of homocysteine, cysteine, choline, and betaine were significantly higher in women with preeclampsia than controls, both in maternal and fetal plasma. There were no differences in folate and vitamin B12 concentrations between the groups, neither for maternal nor fetal samples. Maternal homocysteine concentration was a negative predictor for birth weight only in the preeclampsia group. Elevated homocysteine and cysteine concentration in maternal circulation in preeclampsia is reflected in the fetal circulation. The clinical significance of elevated homocysteine and cysteine concentrations in maternal and fetal compartments in preeclampsia remain to be explored, both regarding fetal growth and development of disease later in life.     

Acute effect of maternal smoking on the maternal and fetal cardiovascular system

Maternal and fetal cardiovascular dynamics were studied in relation to maternal smoking in 18 healthy nulliparous subjects randomly divided into a smoking (n = 9) and a control group (n = 9) between 34 and 38 weeks of gestation. At the end of the study, data from 7 smokers and 7 controls were available for analysis. A significant rise in maternal heart rate and systolic blood pressure was observed during and following smoking one cigarette. A significant increase in fetal heart rate occurred following smoking, whereas mean blood flow velocity and vessel diameter in the fetal descending aorta as measured by pulsed Doppler and time motion techniques did not demonstrate any significant changes.     

Non-invasive prenatal diagnosis by fetal nucleic acid analysis in maternal plasma: the coming of age

Prenatal diagnosis is an important part of obstetrics care. In the current prenatal programmes, definitive diagnosis of fetal genetic or chromosomal conditions is conducted through fetal sampling by amniocentesis or chorionic villus sampling. To obviate the risks of fetal miscarriage that are associated with the invasive sampling procedures, we have been developing non-invasive prenatal diagnostic tests based on cell-free fetal DNA analysis from maternal plasma. To date, fetal sex and rhesus D status determination by circulating fetal DNA analysis is performed clinically in many centres. Strategies for the non-invasive diagnosis of monogenic diseases have been developed. Accurate detection of fetal trisomy 21 by next-generation sequencing has been achieved. Many of the non-invasive prenatal tests could be introduced to the clinics as soon as cost-effective and high throughput protocols are developed.     

Effect of maternal diabetes on the fetal exocrine pancreas

To test the hypothesis that fetal pancreatic exocrine and endocrine function are stimulated in parallel in the diabetic pregnancy, 68 mothers with gestational and pregestational diabetes who underwent amniocenteses after 34 weeks' for the evaluation of fetal lung maturity were enrolled. Amniotic fluid specimens were analyzed for C-peptide and trypsin content. Amniotic fluid specimens were obtained from 92 non-diabetic women undergoing amniocenteses for lung maturity, preterm labor, or premature rupture of membranes. Groups were compared using the Wilcoxon rank-sum test, Kruskal Wallis rank sum test, and Spearman's rank correlation test. C-peptide amniotic fluid concentrations were significantly greater in diabetics (median 0.6 ng/ml) than non-diabetics (median 0.4 ng/ml, P= 0.0001), in pregestational (median 0.6 ng/ml) vs. gestational diabetics (median 0.4 ng/ml, P = 0.006), and greater in proportion to severity of disease according to diabetic class (A1 = 0.4 ng/ml, A2 = 0.55 ng/ml, B = 0.6 ng/ml, C = 0.7 ng/ml, D = 0.85 ng/ml, P = 0.04). No significant differences were detected in amniotic fluid trypsin between the diabetic and non-diabetic or the gestational and non-gestational diabetic groups. There was no correlation between C-peptide and trypsin within the diabetic groups. Stimulation of the exocrine and endocrine pancreas does not occur in parallel in the fetus of the diabetic mother. Although originating as a single organ, pancreatic exocrine and endocrine functions are distinct in both physiologic and pathologic conditions.     

Advances in maternal fetal medicine practice

Maternal fetal medicine (MFM) is a subspecialty of obstetrics that focuses on identified risk pregnancies. The role includes obstetric ultrasound for fetal assessment and diagnosis of anomalies, invasive prenatal diagnosis and management of pregnancies complicated by maternal medical disorders, multiple fetuses and the antenatal management of extreme prematurity. Skill specialisation within MFM includes fetal interventions such as fetal shunting procedures, intrauterine transfusion, fetoscopic laser photocoagulation of anastomotic vessels for twin to twin transfusion syndrome and ex utero intrapartum treatment. MFM specialists are actively involved in clinical and basic science research to improve maternal and neonatal outcomes. Most Australian MFM specialists are associated with metropolitan teaching hospitals. MFM sub‐specialisation has reduced the impact of disability associated with aneuploidy, structural anomalies, multiple pregnancy and extreme prematurity. Management aims are to give families timely counselling, appropriate intervention, and optimisation of the time and location of delivery. The aim of this paper is to update the reader regarding current advances in MFM practices.