Research on pathophysiology, the prediction of onset and the prediction of latent fetal distress in toxemic pregnancy.

1.妊娠高血压综合征(PIH)的病理生理：在PIH中，血管加压系统(PRA和PAC)受到抑制，未观察到肾素分泌对血管紧张素I(AI)负荷的负反馈机制。相反，血管降压系统(血浆缓激肽和hANP水平)在原位条件下被刺激，其对盐负荷的AI的储备功能降低。这些结果表明，血管升压剂和血管降压剂系统在妊高征发病中均不起作用。从血管阻力的角度来看，PIN的外周血管阻力增加，因为细胞内Na~(2+)浓度显著升高，Na~(++)-K~(++)-ATPase活性代偿性升高。妊娠高血压综合征的预测：妊娠1、2周PRA升高与妊娠高血压综合征的发生密切相关，从妊娠中期到足月的PRA评分中，PRA在妊娠高血压综合征发病前几周开始下降，低于正常妊娠下限。钙代谢：妊高征血总钙、游离钙、1，25，(OH)_2、维生素D_3水平低，甲状旁腺激素水平高。低钙血症可能是由于胎-胎盘单位合成1，25，(OH)_2维生素D_3减少引起的肠道钙吸收减少所致。潜在性胎儿窘迫的预测在妊高征中，胎盘功能不全引起的胎儿生长迟缓与潜在的胎儿窘迫密切相关。Morcover，这些发现表明，在怀孕期间对胎儿生长的超声评估也可能有助于预测分娩时的胎儿窘迫。

1. Pathophysiology of pregnancy induccd hypertension(PIH) ; in PIH, the vasopressor system (PRA and PAC) was suppressed, and the negative feedback mechanism of renin secretion against angiotensin I (AI) loading was not observed. On the contrary, the vasodepressor system (plasma bradykinin levels and hANP levels) was stimulated in an in-situ condition, and its reserve function against AI of salt loading was decreased. These results suggest that both the vasopressor and the vasodepressor system do not play a causative role on the onset of PIH. From the point of view on vascular resistance, increase of the peripheral vascular resistance was confirmed in PIN, since intracellular Na^+ concentrations were significantly elcvated and a brcakdown of the compensatory increase of the Na^+ -K^+ -ATPase activities was obsorved.2. Prediction of PIH : High PRA in the lst and 2nd trimester closely correlated to the occurrence of PIH, and in scrial estimation of PRA from 2nd trimester to term, PRA began to dccrease below lower limits of normal pregnancy at several weeks before the onset of PIH.3. Caleium metabolism ; Calcium metabolism in PIH was characteristic of low scrum levels of total calcium, ionized calcium, 1,25, (OH)_2 vitamin D_3 and high serum levels of parathyroid hormone. Hypocalcemia secmed to be a result of the decrease in intestinal calcium absorption mainly caused by the decrease of the synthesis of 1,25, (OH)_2 vitamin D_3 in feto-placental unit.4. Prediction of latent fetal distress ; The fetal growth retardation induced by placental insufficiency strongly correlates with latent fetal distross in cases of PIH. Morcover, these findings indicate that ultrasonographical assessments of fetal growth during gestation might also be useful to predict fetal distress at the time of parturition.