FETAL VELOCIMETRY AND AMINO ACID TRANSPORT IN PREGNANCY

该项目的具体目标涉及正常人的临床研究， 妊娠和妊娠合并胎儿生长受限。 这些研究包括两个方面：1）改进分类， 使用新的胎儿监测技术和2）研究的临床严重程度 氨基酸转运和代谢的稳定同位素方法。 脐静脉血流量直接测量的作用比较 动脉流速测量和胎儿血液化学是 围绕临床严重程度分类的框架进行检查。 同样，从单个胎儿器官获得的额外信息 静脉导管，胎儿肝静脉，胎儿 股动脉、大脑中动脉也与胎儿比较 脐动脉血流速度测定和胎儿化学。 研究在 体内氨基酸胎盘运输和代谢是一个后续我们的 观察到胎儿氨基酸浓度显著 减少胎儿生长受限的妊娠。 非稳态 利用必需和非必需氨基的稳定异构体的研究 脐带穿刺术孕妇体内酸检测 不同氨基酸组的转运：a）确定 它们在体内的相对转运率和B）测试氨基是否 与正常妊娠相比，FGR妊娠的酸转运减少 怀孕的所有氨基酸或特定子集。 稳态稳定 同位素方法也用于测试胎儿/母体是否 注入的氨基酸的稳定同分异构体的富集比 FGR妊娠中的母体循环较低，反映了 运输和增加蛋白质周转。 母性关系 对于正常和FGR妊娠， 利用脐动静脉浓度数据进行研究 剖宫产时的差异。 所有的代谢数据 与FGR妊娠的临床严重程度分类相比， 使用我们之前发布的标准。

The specific aims of this project involve clinical studies in normal pregnancies and pregnancies complicated by fetal growth restriction. The studies cover two aspects: 1) improvements in the classification of clinical severity using new fetal surveillance techniques and 2) studies of amino acid transport and metabolism using stable isotope methodology. The role of direct measurements of umbilical venous blood flow compared to arterial velocimetry measurements and fetal blood chemistry is examined around the framework of the classification of clinical severity. Similarly, the additional information acquired from single fetal organ velocimetry studies of the ductus venosus, fetal hepatic veins, fetal femoral artery, fetal middle cerebral artery are also compared to fetal umbilical arterial velocimetry and fetal chemistries. The studies of in vivo amino acid placental transport and metabolism is a follow up on our observations that fetal amino acid concentrations are significantly reduced in fetal growth restricted pregnancies. A non steady state study utilizing stable isoptomers of essential and non essential amino acids in pregnant women scheduled for cordocentesis examines in vivo transport for different groups of amino acids: a) to define differences in their relative rates of transport in vivo and b) to test whether amino acid transport is reduced in FGR pregnancies compared to normal pregnancies for all amino acids or a specific subset. Steady state stable isotope methodology is also used to test whether the fetal/maternal enrichment ratios for stable isoptomers of amino acids infused in the maternal circulation is lower in FGR pregnancies reflecting decreased transport and increased protein turnover. The relationship of maternal concentration to umbilical uptake for normal and FGR pregnancies is also investigated utilizing data on umbilical arteriovenous concentration differences at the time of cesarean section. All metabolic data are compared to the classification of clinical severity in FGR pregnancies using criteria we have previously published.