American journal of obstetrics and gynecology
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Am. J. Obstet. Gynecol. · May 2000
Changes in hemodynamic parameters and volume homeostasis with the menstrual cycle among women with a history of preeclampsia.
Among women with a history of preeclampsia the prevalence of hemodynamic and clotting disorders is elevated. In this study we tested the hypothesis that the normal cyclic variation in hemodynamic and renal function parameters with the menstrual cycle that is seen among healthy women would be preserved in women with a history of preeclampsia irrespective of whether they had an underlying hemodynamic or clotting disorder. ⋯ Although baseline hemodynamic and volume status among women with a history of preeclampsia differed from that among healthy parous control subjects, the cyclic variation with the menstrual cycle was largely preserved.
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Am. J. Obstet. Gynecol. · May 2000
Effect of single versus multiple courses of antenatal corticosteroids on maternal and neonatal outcome.
Treatment of pregnant mothers with a single course of antenatal corticosteroids significantly reduces neonatal mortality and morbidity. Multiple weekly courses are often given. However, the safety and efficacy of repeated courses of antenatal corticosteroids have not been adequately studied. ⋯ Exposure to multiple courses of antenatal corticosteroids compared with a single course resulted in a significant reduction in the incidence of respiratory distress syndrome in singleton preterm infants delivered within a week of the last corticosteroid dose. This was associated with a reduction in birth head circumference and an increased incidence of maternal endometritis. Whether the potential benefits of repeated therapy clearly outweigh the risks will ultimately be determined in randomized prospective controlled trials.
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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.