REGULATION OF AMNIOTIC FLUID VOLUME

拟议研究的长期目标是了解 羊水调节的详细机制 在正常和非正常情况下的体积。 研究 将在长期插管的妊娠绵羊中进行 在怀孕的最后50天。 先进的方法将是 用于测量羊水量、胎儿尿量 进入羊膜腔，胎儿吞下羊水。 此外，液体和电解质在整个组织中的移动 将在许多条件下探索胎膜。 第一项研究旨在确定在多大程度上， 羊水量的每日变化与 胎儿的尿流率和吞咽能力 以确定是否 胎儿水合作用的变化导致羊水的改变 将生理盐水静脉输注到 胎儿在一段时间内。 羊水和尿囊液量 将分别通过输注等渗液体 在几天内进入这些空间， 相关的体积和组成随着输注而改变， 尿流量和吞咽率 的相对贡献 液体的吞咽和跨膜运动， 电解质对羊水量的调节作用 通过将羊水体积变化与尿液相关联来确定 食管和气管结扎后的血流。 的exent to 胎盘参与调节羊水量 将确定胎儿尿液和羊水的一段时间， 天并将净体积和电解质损失与 经胎盘渗透压和电解质浓度的变化 梯度。 最后，单个激素对 通过输注精氨酸加压素来确定调节， 催乳素、皮质醇或血管紧张素II进入羊水， 将体积和组成的相关变化与 羊水中的激素浓度 统称 拟议的研究很重要，因为它们将大大扩大 我们对羊水量调节的理解。 因为羊水量的异常与 胎儿死亡或围产期结局不良，拟议的研究可能 导致胎儿和新生儿发病率和死亡率降低。

The long-term objective of the proposed studies is to understand the detail mechanisms involved in the regulation of amniotic fluid volume under normal as well as abnormal conditions. The studies will be conducted in chronically catheterized pregnant sheep during the last 50 days of gestation. Advanced methods will be used for measuring amniotic fluid volume, fetal urinary output into the amniotic space, and fetal swallowing of amniotic fluid. In addition, the movement of fluid and electrolytes across the fetal membranes will be explored under a number of conditions. The first study is designed to determine to what extent the large daily variations in amniotic fluid volume are related to variations in fetal urine flow rate and swallowing. To determine whether changes in fetal hydration lead to alterations in amniotic fluid volume, physiological saline will be infused intravenously into the fetus over a period of days. Amniotic and allantoic fluid volume regulation will be explored separately by infusing isotonic fluids into these spaces over a period of days and correlating the associated volume and composition changes with the infusion, urine flow, and swallowing rates. The relative contribution of swallowing and transmembrane movements of fluid and electrolytes to amniotic fluid volume regulation will be determined by correlating the amniotic volume changes with urine flow following esophageal and tracheal ligation. The exent to which the placenta is involved in regulating amniotic fluid volume will be determined fetal urine and amniotic fluid for a period of days and relating the net volume and electrolyte loss to the changes in transplacental osmotic and electrolyte concentration gradients. finally, the contribution of individual hormones to regulation will be determined by infusing arginine vasopressin, prolactin, cortisol, or angiotensin II into the amniotic fluid and relating the associated changes in volume and composition to the hormone concentrations in amniotic fluid. Collectively, the proposed studies are important because they will greatly expand our understanding of the regulation of amniotic fluid volume. Because aberrations in amniotic fluid volume are associated with fetal death or poor perinatal outcome, the proposed studies may lead to a decreased fetal and neonatal morbidity and mortality.