Journal of maternal-fetal investigation : the official journal of French Society of Ultrasound in Medicine and Biology ... [et al.]最新文献

> Objective: There is a reduction in intravascular volume in patients with preeclampsia and eclampsia. Since the secretion of atrial natriuretic peptide (ANP) by human atrial myocytes is stimulated by increased intraatrial pressure or atrial distention, we sought to determine whether circulating maternal plasma ANP concentrations were lower in patients with severe preeclampsia and eclampsia compared with normal pregnant women. Methods: Fifteen patients with mild preeclampsia, 15 with severe preeclampsia, 15 with eclampsia, and 38 normotensive pregnant women were taken as the control group. All the women were age-matched and in their third trimester. The level of ANP in these patients was measured during the third trimester and in the postpartum period by a specific radioimmunoassay. At the same time, routine laboratory tests for eclampsia and preeclampsia such as uric acid, creatinine, and urine protein levels were obtained. Results: ANP levels were significantly higher in the antepartum periods in women with mild preeclampsia (20.7 +/- 6), severe preeclampsia (28.9 +/- 9), and eclampsia (26.6 +/- 6.5) than those in normotensive pregnant women (15.7 +/- 3.5; P < 0.05 and P < 0.001, respectively). As the severity of preeclampsia increased, the mean values of ANP became higher. Conclusions: ANP levels in preeclamptic and eclamptic women were found to be higher than those in normotensive pregnant women. There is a correlation between the severity of toxemia and plasma ANP levels. The mechanism(s) responsible for the elevation requires further investigation.

> Objective: This paper describes the deliberations of an interdisciplinary group of clinical and basic scientists who met at the National Institute of Child Health and Human Development to discuss the potential role of fetal behavior in assessing fetal well being and predicting neonatal outcome. The conference focused on three aspects of fetal behavior: 1) habituation; 2) state transitions; and 3) movement. Methods: The participants consisted of 25 leaders in the fields of obstetrics, perinatal medicine, neonatology, developmental psychobiology, developmental neuroscience, developmental psychology, ethology, and mathematics. The meeting was divided into three parts. In each of these a plenary speaker (a recognized expert in his field) began the session with an overview of the scientific theme. Two respondents, with research expertise in fetal research (animal models or human fetuses) followed with remarks on the plenary talk and comments based on their own studies. At the conclusion of these comments, the participants met in small groups to discuss the plenary proceedings and their implications for assessing human fetal well being and predicting outcome. At the conclusion of the small group deliberations all of the participants reconvened in a plenary session. During this part of the meeting a rapporteur from each small group summarized their discussions. Results and Conclusions: 1) Fetal habituation: there was a general consensus that research on this aspect of fetal behavior may have a high payoff for assessing human fetal well being and predicting neonatal outcome. 2) Behavioral state transitions: participants agreed that transitions afford investigators with an indication of when (timing) and how (models) behavior changes within and between developmental periods. Knowledge of transitions during development allows for tracking of behaviors that may be necessary for the fetus to adapt to its in utero environment or prepare for its postnatal life. 3) Chaos theory and fetal movement: participants concluded that non-linear dynamics systems analysis models could be useful to analyze "noise" within a measurement system; better define time scales; and increase resolution and thereby better identify "signals."

> Background: We have recently reported that progesterone caused a receptor-mediated, cAMP-dependent relaxation in isolated placental arteries and veins from normal term pregnancies that may be important in maintaining adequate blood flow in the placental circulation. Objective: To further investigate the activity of progesterone and some of its metabolites in both placental and umbilical vessels. Study design: Isolated human placental and umbilical arteries and veins from normal term pregnancies, incubated in Krebs-bicarbonate buffer and submaximally precontracted with potassium chloride, were exposed to cumulative concentrations (0.01-30 µm) of progesterone, 5beta-pregnane-3,20-dione, 5alpha-pregnane-3,20-dione, or 5alpha-pregnane-3beta-ol-20-one. Results: All experimental progestins produced concentration-dependent relaxations in precontracted human placental and umbilical arteries and veins. These relaxations were endothelium-independent. Progesterone and 5beta-pregnane-3,20-dione appeared to be the most potent and efficient of the tested progestins, whereas 5alpha-pregnane-3beta-ol-20-one produced the least relaxation in the same vessels. Conclusions: These results suggest that not only progesterone, but also its metabolites, may be of physiological importance in the regulation of umbilico-placental vascular tone. Additionally, it appears that the umbilical blood vessels possess the same relaxation to progesterone as placental arteries and veins. Taken together, these results indicate a potential role for progesterone and its metabolites in maintaining adequate blood flow in the umbilico-placental circulation.

> Objective: To investigate the relationship between maternal weight and serum alpha-fetoprotein (AFP) and free beta-human chorionic gonadotropin (beta-hCG) levels and to determine the methodology of correction formulas for influencing the results of Down syndrome screening in an Asian population. Methods: 8,194 normal singleton pregnancies without any congenital anomalies were screened using AFP and free beta-hCG between 14 and 22 weeks of gestation. Down syndrome risk was calculated by bivariate gaussian algorithm that combined information from the two biochemical measurements and maternal age. The all points regression method and median regression method were used to approach the study cases. Linear and quadratic regression correction formulas for AFP and free beta-hCG, either in analyte multiples of the median (MoM) or log analyte MoM, against maternal weight have been proposed in this study. Results: The mean maternal weight is 54.95 +/- 7.36 kg in Taiwanese pregnant women during the second trimester. There is a distinctly inverse relationship between maternal weight and serum marker levels. The log quadratic regression correction formula was the most satisfactory equation fit to the distribution of both AFP and free beta-hCG levels with a wide weight range. Routine weight correction may have the small benefit of reducing the screen-positive rate 0.36% at the risk cut-off level of 1:270. Conclusions: Maternal weight may affect the AFP and free beta-hCG levels. Although there is no discernible effect in maternal weight adjustment, it is worth making weight corrections for serum marker levels in order to reduce individual variance.

> Objective: Optical spectroscopy can monitor changes in cerebral oxyhemoglobin (HbO), deoxyhemoglobin (Hb), and total hemoglobin (HbT = Hb + HbO). The purpose of this study was to identify which one of these three optical variables would be the best correlate of cerebral hemodynamics and oxygenation accompanying different physiological conditions known to affect cerebral perfusion pressure and oxygenation. Methods: Eleven anesthetized and ventilated newborn piglets were subjected to: 1) hyperoxic hypercapnia, 2) asphyxia from room air, 3) hypertension, 4) hypotension, and 5) cerebral venous congestion. Optical measurements were recorded continuously along with carotid blood flow (CaBF) measured by the transit time Doppler technique and arterial hemoglobin oxygen saturation (SaO2) measured by pulse oximetry. Results: A good positive HbT-CaBF correlation was recorded during hypercapnia (r = 0.816), asphyxia (r = 0.846), hypertension (r = 0.72), and hypotension (r = 0.95), where as negative correlation was recorded during venous congestion (r = -0.91). A good positive correlation HbO-SaO2 was recorded during asphyxia (r = 0.842) and hypotension (r = 0.86), whereas no HbO-SaO2 agreement occurred during hypercapnia (r = 0.23), hypertension (r = 0.19), and venous congestion (r = 0.34), when SaO2 did not change at all. A good positive HbO-SaO2 correlation was recorded during hypercapnia (r = 0.84), hypertension (r = 0.91), and hypotension (r = 0.94), suggesting a high HbO dependence on changes in CaBF. Conclusions: We demonstrated that none of the optical variables (Hb, HbO, HbT) alone can be used as a correlate of cerebral hemodynamics and oxygenation over a broad range of cerebral perfusion pressure and oxygenation. However, all three variables combined (i.e. optical patterns) strongly reflect the changes in cerebral hemodynamics and oxygenation accompanying those physiological conditions. These and similar patterns could potentially serve as a reference model for future studies in the human fetus where "gold standard" correlation methods do not exist.

> Objective: To describe the perinatal characteristics of neurologically impaired infants with normal intrapartum fetal heart rate (FHR) patterns. Methods: In a registry of 300 neurologically impaired singleton term infants, a retrospective chart review was undertaken to analyze those patients with a normal intrapartum FHR pattern, i.e. reactive FHR pattern with a normal baseline rate throughout labor, and a subsequent finding of central nervous system impairment. Neonates with an abnormal intrapartum FHR pattern or a traumatic birth were excluded. In addition, the four criteria necessary for intrapartum asphyxia were as follows: arterial pH <7.00, Apgar score

> Objective: The physiology of hiccups is a sharp inspiratory gasp against a closed glottis, causing a sudden sharp fall in intrathoracic pressure. This would be expected to cause an increase in venous return to the chest; however, we noticed that umbilical venous Doppler waveforms indicated a cessation of flow during hiccups. We observed other hiccuping fetuses to ascertain the range of response of the fetal umbilical vein Doppler waveforms and derive an explanation for them. Methods: Fetuses who were hiccuping at the time of their antepartum testing had observations of umbilical vein flow made, and representative recordings of the trace were obtained. Results: Ten Doppler traces were obtained from fetuses during hiccuping. In every case there was a brief fall of the umbilical vein Doppler waveform to base line, indicating an arrest of flow. Conclusions: Fetal hiccups are associated with arrest of flow in the umbilical vein as demonstrated by Doppler waveforms. This is contrary to predictions based on previously demonstrated fetal physiology of hiccups. We speculate that the findings result from obstruction of the venous return by a combination of the contracting diaphragm at the level of the inferior vena cava as it passes through the diaphragm, by raised intra-abdominal pressure from the descending diaphragm, and possibly from kinking of the umbilical vein at the umbilical ring.

> At week 32 of a pregnancy complicated by maternal seizures, fetal ultrasonography showed hydrocephalus and an intracranial hyperechoic mass identified by magnetic resonance imaging as subacute right thalamic hemorrhage, with aqueductal obstruction. Fetal intracranial bleeding may be a cause factor of perinatal death complicating maternal epilepsy.

> Objective: To establish whether uterine artery flow velocity waveforms in the second trimester are associated with adverse pregnancy outcome in women with a poor obstetric history. Methods: We reviewed the obstetric case notes of 50 women with a poor obstetric history in previous pregnancies in whom uterine artery flow velocity waveforms had been obtained at 18 weeks gestation. Results: In this population 40% had an adverse pregnancy outcome (preeclampsia, pregnancy-induced hypertension, preterm delivery, birthweight <10th percentile or perinatal death). Preeclampsia, perinatal death, and preterm delivery were all significantly associated with abnormal uterine artery waveforms at 18 weeks. Conclusions: Assessment of uterine artery flow velocity waveforms at 18 weeks gestation shows promise as a screening test in the high risk obstetric population. The technique requires formal evaluation in a prospective, double blinded study.

>Background: We have recently described a dose-dependent, endothelium-independent relaxation to progesterone in human placental arteries and veins. This receptor-operated, cAMP-mediated relaxation may be of value in maintaining adequate blood flow in the placental circulation.Objective: To investigate if gestational diabetes alters this relaxation to progesterone.Study design: Isolated human placental vessels from pregnancies complicated by gestational diabetes and well matched controls (uncomplicated term pregnancies), incubated in Krebs-bicarbonate buffer and submaximally precontracted with KCl, were exposed to cumulative doses of progesterone (0.01-30 µmol/liter), nitroglycerin (0.001-1 µmol/liter), arachidonic acid (0.01-10 µmol/liter), forskolin (0.01-10 µmol/liter) and 5-hydroxytryptamine (serotonin, 0.01-10 µmol/liter).Results: The relaxation to progesterone in vessels from patients with gestational diabetes was reduced by 50-100% in both arteries and veins compared with control (for example, relaxation to 10 µmol/liter progesterone was reduced from 52 +/- 7 to 18.8 +/- 5.4% in arteries and from 58 +/- 8 to 19 +/- 5.2% in veins, n = 7-13, P < 0.05), whereas responses to the other vasoactive agents were unchanged.Conclusion: Based on these results, gestational diabetes significantly reduces the relaxation to progesterone in human placental vessels. This alteration of the relaxation to progesterone may lead to an increase in placental vascular resistance and possibly to a reduction of placental blood flow.