UMBILICAL VENOUS BLOOD FLOW & AMINOACID TRANSPORT & METABOLISM

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。 的 胎盘氨基酸转运及代谢动态研究 观察到胎儿氨基酸浓度显著 减少胎儿生长受限的妊娠。 非稳态研究 利用必需和非必需氨基酸的稳定异构体， 预定进行脐带穿刺术的孕妇检查体内转运 不同组氨基酸的比率; a.） 来定义 其体内转运的相对速率和B.） 来测试氨基 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 同位素方法也被用来测试胎儿母体是否 对于注入到该溶液中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， 利用脐动静脉差异数据进行研究 在剖腹产时确定。 最后，直接作用 脐静脉血流量与动脉血流量的比较 检查胎儿周围的速度测量和胎儿血液化学。 FGR妊娠临床严重程度分类的框架。

The specific aims of this project involve clinical studies in normal pregnancies and pregnancies complicated by fetal growth restriction. The study of in vivo amino acid placental transport and metabolism follow-up 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 nonessential amino acids in pregnant women scheduled for cordocentesis examines in vivo transport rates for different groups of amino acids; a.) to define differences in their relative rates of in vivo transport 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 into 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 arterial venous differences determined at the time of cesarean section. Finally the role of direct measurements of umbilical venous blood flow compared to arterial velocemetry measurements and fetal blood chemistry is examined around the framework of the classification of clinical severity in FGR pregnancies.