Biomedical subjects

W F O'Brien

Publications and source records attributed to W F O'Brien.

At least 91 records · Page 5Linked to original sources

PubMed1990

The effect of magnesium sulfate infusion on systemic and renal prostacyclin production.

Recent in vitro studies have suggested that magnesium sulfate (MgSO4) infusions may increase prostacyclin production. We studied the effect of MgSO4 infusion on prostacyclin (PGI2) metabolite excretion in women with either pregnancy induced hypertension or preterm labor. Excretion of renal and systemic metabolites of PGI2 was measured prior to and following the start of MgSO4 infusion in the two groups. An increased in renal PGI2 metabolite preterm labor excretion was noted in the hypertension group but no change was noted in systemic PGI2 excretion in either group. These data fail to support a generalized, short term increase in endothelial cell PGI2 production as the basis for the beneficial effect of MgSO4.

Adult↗

PubMed1990

Predicting preeclampsia.

Recent studies suggest that drugs affecting prostacyclin and thromboxane production may be able to affect the development of preeclampsia. In order to use these agents effectively, we must be able to select properly women at high risk. This review evaluates a number of historic and physical factors and laboratory tests that may aid in the prediction of preeclampsia. Family history, parity, and the roll-over test are currently the most efficient methods that are widely available. Two relatively new laboratory tests, plasma fibronectin concentration and urinary calcium/creatinine ratio, hold the greatest promise for the near future.

Angiotensin II↗

PubMed1990

Acute pyelonephritis in pregnancy: a prospective study of oral versus intravenous antibiotic therapy.

Ninety pregnant women admitted to the high-risk pregnancy unit with a diagnosis of acute pyelonephritis were randomized to receive either oral (cephalexin 500 mg every 6 hours) or intravenous (IV) (cephalothin 1 g every 6 hours) antibiotic therapy. All patients were initially hydrated with 1 L of normal saline IV over 4 hours. Neither parenteral analgesics nor antiemetics were used. Bacteremia was noted in 13 (14.4%) of the 90 patients and mandated IV therapy. There was no difference between the oral and IV groups concerning predefined criteria for successful therapy (91.4 versus 92.9% successful therapy, respectively). No characteristic available at presentation predicted bacteremia or ultimate failure of therapy. Two patients (2.2%) experienced significant complications. These data suggest that in nonbacteremic patients, oral antibiotics are both safe and effective for the treatment of acute pyelonephritis in pregnancy.

Acute Disease↗

PubMed1989

The association between apolipoprotein A-I and prostacyclin binding in human serum.

The stability of Prostacyclin in human blood is dependent upon binding to circulating proteins. Although this binding has been considered to be primarily due to albumin, a recent report has suggested that apolipoprotein A-I is responsible. We compared prostacyclin binding to the concentration of albumin and apolipoprotein A-I in several groups of sera with known differences in the ability to bind prostacyclin. Our results indicate a strong correlation with albumin concentration but no correlation between binding and the concentration of apolipoprotein A-I. It appears that in the human circulation albumin concentration is the most important determinant of prostacyclin binding.

Apolipoprotein A-I↗

PubMed1989

Influence of albumin and non-esterified fatty acids on serum prostacyclin binding in pregnancy.

We investigated the etiology of the previously documented decrease in serum prostocyclin binding during pregnancy. Addition of albumin to the serum of pregnant women failed to raise binding to non-pregnant levels. Pregnancy serum bound significantly more prostacyclin following the removal of non-esterified fatty acids and the addition of fatty acid free albumin resulted in a rise in binding to non-pregnant levels. We conclude that serum protein prostacyclin binding is affected by both albumin concentration and non-esterified fatty acids.

Blood Proteins↗

PubMed1989

Fetal lung maturation: the combined use of corticosteroids and thyrotropin-releasing hormone.

The purpose of this randomized study was to evaluate whether the combined use of corticosteroids and thyrotropin-releasing hormone would enhance fetal lung maturation to a greater degree than would corticosteroids alone. The study was restricted to patients under 34 weeks' gestation with a lecithin/sphingomyelin (L/S) ratio less than 2.0. The patients were randomized into a study group receiving intravenous thyrotropin-releasing hormone along with intramuscular corticosteroids over 48 hours and a control group receiving only corticosteroids. Patients undelivered 1 week after the onset of therapy underwent a repeat amniocentesis to document changes in the L/S ratio. In those patients delivering within 1 week of therapy, the neonatal clinical course was established by two investigators blinded to the antenatal therapy. Compared with the control group, the group receiving antenatal corticosteroids plus thyrotropin-releasing hormone showed a greater post-therapy increase in L/S ratio, fewer respirator days, and a lower incidence of bronchopulmonary dysplasia. The results of this study suggest that the combined use of corticosteroids and thyrotropin-releasing hormone results in enhanced fetal pulmonic maturation superior to that achieved with corticosteroids alone.

Betamethasone↗

PubMed1989

Serum prostacyclin binding and half-life in normal and hypertensive pregnant women.

The effective half-life of prostacyclin in human serum is highly dependent on binding to serum proteins. Abnormalities in prostacyclin binding appear to be important in some patients with thrombotic thrombocytopenic purpura. We investigated prostacyclin binding and half-life in normotensive and hypertensive pregnant women and in nonpregnant controls. Pregnancy was associated with a decrease in serum prostacyclin binding and a shorter prostacyclin half-life. This decrease was even greater in women with hypertensive disorders. The decrease in prostacyclin half-life in hypertensive disorders may play an important role in the pathogenesis of these disorders. Measurement of both production and metabolism, however, will be required to adequately assess the role of prostacyclin in normal and abnormal gestation.

Adult↗

PubMed1989

Efficacy and safety of indomethacin versus ritodrine in the management of preterm labor: a randomized study.

One hundred six patients in preterm labor with intact amniotic membranes and gestational age less than or equal to 32 weeks were randomized to receive either ritodrine hydrochloride or a 48-hour course of indomethacin for tocolysis. The relative efficacy, maternal and neonatal safety, and costs were evaluated to determine which may be the more appropriate first-line pharmacologic agent used to manage preterm labor. Fifty-four patients and 52 patients were randomized to receive ritodrine hydrochloride or indomethacin, respectively. Ritodrine hydrochloride and indomethacin were equally effective in inhibiting uterine contractions and delaying delivery. Delivery was delayed for at least 48 hours in 83 and 94%, and for at least 7 days in 70 and 75% of patients receiving ritodrine or indomethacin, respectively. Tocolysis with indomethacin was associated with no maternal side effects, whereas tocolysis with ritodrine hydrochloride was associated with a 24% incidence of serious cardiovascular and metabolic adverse effects prompting discontinuation of the drug. There were no differences in outcome between the infants exposed to indomethacin versus ritodrine hydrochloride when delivered either remote from therapy or during therapy, except for a statistically higher serum glucose in the infants exposed to ritodrine hydrochloride when delivered during tocolytic therapy. There were no cases of premature closure of the ductus arteriosus or pulmonary hypertension. Tocolysis with indomethacin was 17 times less costly than tocolysis with ritodrine hydrochloride. For gestations less than or equal to 32 weeks complicated by preterm labor, indomethacin may be an appropriate alternative as a first-line tocolytic agent.

Adult↗

PubMed1989

Use of ampicillin and corticosteroids in premature rupture of membranes: a randomized study.

A randomized study was conducted to investigate the effects of antenatal corticosteroids and ampicillin in the management of preterm pregnancies under 34 weeks complicated by premature rupture of membranes. Patients with documented lecithin/sphingomyelin (L/S) ratios of less than 2.0 and a singleton gestation were eligible to participate in the study. One hundred sixty-five patients qualified and were randomized, using sealed envelopes, to four study groups. All patients were followed expectantly. Group I (41 patients) received neither ampicillin nor corticosteroids. Group II (43 patients) received 24 mg of antenatal betamethasone. Group III (37 patients) received 2 g of intravenous ampicillin every 6 hours, with discontinuation of antibiotic therapy if cultures were negative for pathogenic bacteria. Group IV (44 patients) received both corticosteroids and ampicillin as described for groups II and III, respectively. Compared with patients not receiving corticosteroids, those administered antenatal corticosteroids experienced a reduction in the incidences of respiratory distress syndrome (53 versus 26%), bronchopulmonary dysplasia (23 versus 9%), severe grades of intracranial hemorrhage (15 versus 3%), and patent ductus arteriosus (18 versus 6%), with no difference in the incidence of maternal or neonatal infection. Compared with patients not receiving antenatal antibiotics, the group of patients treated with ampicillin on admission had a lower incidence of clinical chorioamnionitis (4 versus 26%) and neonatal sepsis (5 versus 10%). This reduction in infectious morbidity by antenatal ampicillin was restricted to those patients (28.4% of the study population) colonized with group B streptococci.(ABSTRACT TRUNCATED AT 250 WORDS)

Adrenal Cortex Hormones↗

PubMed1989

The effect of mode of delivery on the risk of intraventricular hemorrhage in nondiscordant twin gestations under 1500 g.

The effect of birth order, presentation, and mode of delivery on neonatal outcome in nondiscordant twin gestations under 1500 g was investigated. All neonates had echoencephalograms performed by the fourth day of life to diagnose the presence and severity of intraventricular hemorrhage. One hundred fifty-six sets of twins were included in the study, of which 59 were in a vertex/vertex presentation, 59 in vertex/nonvertex presentation, and 38 with twin A in a nonvertex presentation. Second twins were characterized by a higher incidence of respiratory distress syndrome (RDS): 66 versus 54% (P less than .05), and severe grades of intraventricular hemorrhage: 30 versus 19% (P less than .01). For vertex/vertex twins, cesarean delivery did not result in improved outcome. Rather, the incidence of RDS was significantly increased in neonates from this group delivered by cesarean birth: 67 versus 46% (P less than .01). Among twins in which at least one of the fetuses was in a nonvertex presentation, those born via cesarean delivery demonstrated a lower incidence of both severe grades of intraventricular hemorrhage and mortality. However, after multivariate analysis to correct for differences in birth weight between the groups, no advantage for cesarean delivery could be demonstrated. Therefore, differences in birth weight, rather than in mode of delivery, accounted for the differences in the neonatal outcome of nonvertex-presenting twins.

Birth Order↗

PubMed1989

Instructional model for percutaneous fetal umbilical blood sampling.

Percutaneous umbilical cord sampling is gaining widespread acceptance for diagnostic and therapeutic procedures on the fetus. The sampling technique has been reported to be relatively safe in experienced hands. Attainment of the skills for this procedure follows a learning curve, with improvement in successful sampling occurring over time. This paper presents a practical instructional model for percutaneous umbilical cord sampling.

Blood Specimen Collection↗

PubMed1988

Adnexal mass occurring with intrauterine pregnancy: report of fifty-four patients requiring laparotomy for definitive management.

Fifty-four cases in which surgical intervention during pregnancy was required for definitive therapy of adnexal masses were reviewed. The calculated incidence of adnexal masses that required surgical intervention during pregnancy in our primary population (patients who were not referred for evaluation of an already identified mass) was one case per 1300 live births. A malignant tumor was found in 5.9% of the pregnant patients who underwent exploratory celiotomy for therapy of an adnexal mass. Those pregnant women who underwent emergency celiotomy because of hemorrhage or torsion as a complication of an adnexal mass spontaneously aborted or underwent premature delivery more frequently than those patients who underwent elective celiotomy for removal of the mass (p less than 0.001). On the basis of this review, we recommend that pregnant women with persistent adnexal masses undergo elective extirpation of the mass in the second trimester of pregnancy.

Adnexal Diseases↗

PubMed1988

The sequential use of estradiol and prostaglandin E2 topical gels for cervical ripening in high-risk term pregnancies requiring induction of labor.

We compared the safety and efficiency of 200 mg of estradiol valerate prepared as a topical cervical gel as a preripening agent when used 6 hours before the application of 2 mg of prostaglandin E2 gel for the purpose of cervical ripening in 40 high-risk obstetric patients before indicated oxytocin induction of labor. When compared with a placebo prostaglandin E2 dosage, the estradiol had no effect on the change of Bishop score, length of labor, amount of oxytocin required, or the cesarean delivery rate. While no uterine contractions were noted after the application of the estradiol, 85% of patients had recordable uterine activity after the application of prostaglandin E2, suggesting that even at the 2 mg dosage this sequential regimen is not appropriate for local cervical ripening.

Administration, Topical↗

PubMed1988

Serum prostacyclin binding and half-life in the umbilical circulation.

Serum prostacyclin binding and half-life was measured in twenty pairs of maternal and umbilical venous samples and in twenty non-pregnant controls. When compared to non-pregnant values both umbilical and maternal samples demonstrated significantly lower albumin concentrations, percentage of prostacyclin binding and shorter prostacyclin half-life.

Epoprostenol↗

PubMed1988

The effect of prostaglandin D2 on angiotensin converting enzyme.

Intravenous administration of prostaglandin D2 (2, 4 and 8 micrograms/kg) in the rat resulted in a dose-dependent decrease in arterial pressure with partial recovery occurring during the course of the experiment. Hematocrit and hemoglobin decreased in all groups, probably related to the blood withdrawal and volume replacement. Increase in serum glucose is not specific to prostaglandin D2 and a progressive increase occurred even in the vehicle controls. Despite the fact that arterial pressure decreased with the injection of this prostanoid, angiotensin-converting enzyme did not change significantly. The results of this study demonstrate no association between the administration of prostaglandin D2 and angiotensin-converting enzyme within the concentrations we have used in these experiments.

Animals↗

PubMed1988

Carbohydrate intolerance in patients receiving oral tocolytics.

This prospective study was designed to evaluate the effects on glucose metabolism of terbutaline used as an oral tocolytic agent. Eighty-six patients were studied when admitted for preterm labor from 24 to 35 weeks' gestation. After intravenous tocolysis, these patients were maintained on 5 mg of terbutaline every 4 or 6 hours. An oral 50 gm, 1-hour glucose challenge test was done 48 hours after terbutaline dosing began. All abnormal glucose challenge test results (greater than or equal to 135 mg/dl) were followed by a standard 100 gm oral glucose tolerance test. Sixty-three percent (54 of 86) of the terbutaline group had an abnormal 1-hour screening result, which was significantly different than the 26.7% (23 of 86) observed in the control group (p less than 0.001). The mean fasting blood sugar and 1-hour postchallenge values were significantly higher in the study than in the control group (p less than 0.0001). Ten of 86 in the treated group (11.6%) and 2 of 86 in the control group (2.3%) with abnormal results met the criteria for gestational diabetes. These numbers achieve statistical significance at p less than 0.05. This study shows a significant effect of oral terbutaline therapy on glucose tolerance during pregnancy. Patients receiving oral terbutaline therapy for suppression of preterm labor should undergo screening for gestational diabetes.

Adult↗

PubMed1988

The use of antenatal vitamin K in the prevention of early neonatal intraventricular hemorrhage.

To establish the effect of antenatal vitamin K on the incidence and severity of intraventricular hemorrhage, 92 patients destined to deliver infants less than 32 weeks' gestation were, in a prospective fashion, randomly assigned to two groups. Group I received 10 mg of vitamin K1 intramuscularly every 5 days until delivery. Group II received no antenatal vitamin K1 therapy. There were 100 neonates less than 1500 gm, equally divided between groups I and II with respect to gestational age, birth weight, race, sex, presentation, route of delivery, duration of labor, Apgar scores, and arterial umbilical cord acid-base balance. The antenatal use of vitamin K resulted in significant reduction in the prothrombin time (12.7 versus 15.2 seconds) and partial thromboplastin time (42.6 versus 58.9 seconds; p less than 0.05). Furthermore, group I experienced a lower incidence of total (16% versus 36%) and severe (0% versus 11%) grades of intraventricular hemorrhage (p less than 0.05). This study suggests that the antenatal use of vitamin K may result in a reduction and severity of intraventricular hemorrhage in the neonate less than 1500 gm.

Blood Coagulation↗

PubMed1988

A randomized study of antibiotic therapy in idiopathic preterm labor.

A randomized study was undertaken to test the effects of antibiotics as an adjunct to established methods of tocolysis. One hundred fifty patients with cervical dilation of 1 cm or more and no clinically identifiable cause for preterm labor qualified for the study. Fifty-three (35%) received 500 mg ampicillin orally every 6 hours, 50 (33%) received 500 mg erythromycin orally every 6 hours, and 47 served as controls. Antibiotics were prescribed for 10 days, and the treatment was not altered by the results of cervical cultures. Of these 150 patients, 16 (11%) had positive amniotic fluid cultures. The pregnancies with positive amniotic fluid culture were characterized by significantly less time gained after admission (2.6 versus 28.7 days) and lower birth weight (1262 versus 2470 g) than in those with negative cultures. Histologic studies of the placenta revealed chorioamnionitis in 22 (16%) of 134 patients with negative amniotic fluid cultures; these pregnancies were associated with less time gained after admission (12.5 versus 31.9 days) and lower birth weight (1680 versus 2618 g) compared with pregnancies without histologic chorioamnionitis. In patients with similar gestational age and cervical dilation, the adjunctive use of antibiotic therapy resulted in a statistically significant delay from admission to delivery (30 versus 17 days). In cases of negative amniotic fluid cultures, cervical colonization with group B streptococcus and/or Gardnerella vaginalis increased the risk of prematurity, which improved significantly when ampicillin was given.

Adolescent↗