The experimental study of the effects of sequential fetal acidemia on the susceptibility of circulatory failure in adulthood.

本研究的目的是探讨胎儿循环衰竭对胎儿心血管和脑神经系统的影响。胎儿编程假说提出，发育期的不利条件可能导致成年期疾病。有证据表明，高血压、缺血性心血管疾病、脑梗死等可在子宫内获得。胎儿迅速成熟以适应不良环境，导致外周血管功能障碍被认为是其发病的主要原因之一。采用肌电描记法研究了营养不良对绵羊胎儿胎盘血管功能的影响。结果表明，孕早期饮食限制显著改变了孕中期胎盘血管调节功能。从妊娠中期开始，这种功能表现出下降的趋势。提示一氧化氮在异常应激状态及应激后可能起重要作用 ...更多信息 妊娠中晚期营养不良胎儿的胎儿血压调节系统是在异常条件下形成的（2005，Kimura Y）。血管药理作用存在种属差异。我们在分娩时检查了人胎盘的血管反应。正常胎儿妊娠晚期胎盘血管亦有扩张反应。(2006为了探讨胎儿循环衰竭对脑神经系统的影响，我们观察了一只绵羊胎儿在脐带受压时的皮层脑电图（ECoG）、颈动脉血流和动脉血压的变化。当胎儿动脉pH值为7.18时，即使在pH值下降到严重的胎儿酸血症之前，在脐带压迫过程中也出现了特征性的ECoG尖峰脉冲。这些结果表明，如果脊髓压迫反复或延长，这种由轻度循环衰竭引起的异常脑兴奋可导致胎儿脑功能障碍（2006年Takahash T，Okamura K）。少

The purpose of this research is to examine the influence of fetal circulatory failure on the fetal cardiovascular and cerebral nerve system as the adjustment system. The fetal programming hypothesis proposes that adverse conditions at periods of development may lead to adulthood disease. Evidence suggests that hypertension and ischemic cardiovascular disease, brain infarction can be acquired in uterus. One of the main causes of this disease has been considered peripheral vascular dysfunction of fetus resulting from rapid maturation to adapt those bad conditions. We investigated influences of under-nutrition on placental vascular function of sheep fetus using myography. It was revealed that dietary limitation from early gestation markedly changes placental vascular regulatory function in mid-gestation. This function showed a tendency to decline dilatation from mid-gestation. Our study indicated that Nitric oxide may play an important role in those abnormal stressful condition and after … More that the fetal blood pressure regulatory system of under-nutrition fetus in mid-to- late gestation is formed under abnormal condition (2005, Kimura Y). There is a species difference in vascular pharmacological function. We checked the vascular reaction of human placenta at delivery. The same dilatation reaction of vessels of human placenta was noticed in late gestation of normal fetus. (2006 Imai N, Okamura K) And to investigate the effect of circulatory failure of fetus on cerebral nerve system, we examined the changes in electrocorticogram (ECoG), cartid artery blood flow, and arterial blood pressure of a sheep fetus during cord compression. A characteristics burst of ECoG spikes emerged during cord compression at fetal arterial pH 7.18 even before the pH went down to severe fetal acidemia. These results suggest that this abnormal brain excitement caused by mild circulatory failure can lead to fetal brain dysfunction, if cord compression is repeated or prolonged (2006 Takahash T, Okamura K). Less