American journal of obstetrics and gynecology
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Am. J. Obstet. Gynecol. · Apr 2000
Increased concentrations of plasma neuropeptide Y in patients with eclampsia and preeclampsia.
Epinephrine and norepinephrine are associated with the hyperstimulation of the sympathetic nervous system. Neuropeptide Y is a potent vasoconstrictive substance that is released in response to sympathetic nerve stimulation. ⋯ We have concluded that the level of neuropeptide Y in plasma is increased in women with eclampsia and preeclampsia. Elevated plasma neuropeptide Y levels may play a key role in the development of eclampsia and preeclampsia.
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Am. J. Obstet. Gynecol. · Apr 2000
Expression and regulation of the messenger ribonucleic acid encoding the prostaglandin F(2alpha) receptor in the rat myometrium during pregnancy and labor.
We examined expression of messenger ribonucleic acid encoding the prostaglandin F(2alpha) receptor in the rat myometrium throughout late gestation and its regulation by progesterone and mechanical stretch. ⋯ Increased myometrial expression of prostaglandin F(2alpha) receptor messenger ribonucleic acid during term and preterm labor is temporally associated with progesterone withdrawal but is not dependent on mechanical stretch of the myometrium.
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Am. J. Obstet. Gynecol. · Apr 2000
The role of diacylglycerol as a modulator of oxytocin-stimulated phasic contractions in myometrium from pregnant and nonpregnant rats.
The role of diacylglycerol in the phosphatidylinositol-signaling pathway is to activate protein kinase C. In the myometrium, protein kinase C activation leads to inhibition of phasic contractions. These studies are designed to determine why stimulation of the phosphatidylinositol-signaling pathway caused by oxytocin does not cause a paradoxical suppression of contractions through diacylglycerol production and protein kinase C activation. Specifically, these studies were performed to test the hypothesis that diacylglycerol catabolism is significant in myometrial tissue, thereby precluding its availability for the activation of protein kinase C. ⋯ These studies have demonstrated that prevention of diacylglycerol degradation, especially in response to inhibition of myometrial diacylglycerol kinase, results in the paradoxic oxytocin-mediated suppression of total myometrial contractile activity. These observations support the hypothesis that, when its catabolism is prevented, diacylglycerol produced in response to stimulation of the phosphatidylinositol-signaling pathway by oxytocin becomes available for protein kinase C activation, resulting in inhibition of myometrial contractile activity.
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Am. J. Obstet. Gynecol. · Apr 2000
Hypertensive disorders in twin versus singleton gestations. National Institute of Child Health and Human Development Network of Maternal-Fetal Medicine Units.
This study was undertaken to compare rates and severity of gestational hypertension and preeclampsia, as well as perinatal outcomes when these complications develop, between women with twin gestations and those with singleton gestations. ⋯ Rates for both gestational hypertension and preeclampsia are significantly higher among women with twin gestations than among those with singleton gestations. Moreover, women with twin pregnancies and hypertensive complications have higher rates of adverse neonatal outcomes than do those with singleton pregnancies.