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Biomedical subjects

J Ducey

Publications and source records attributed to J Ducey.

13 recordsLinked to original sources

Effect of thromboxane A2-receptor antagonist on bradykinin-induced bronchoconstriction in asthma.

The role of the thromboxane A2 (TxA2) receptor in bradykinin-induced bronchial responses was investigated in this study by using a selective and potent TxA2-receptor antagonist BAY u 3405. Eleven asthmatic subjects were randomized to receive 50 mg of BAY u 3405 or matched placebo in a crossover and double-blind fashion. Ninety minutes after dosing, serum was taken for drug assay, and subjects underwent provocation with bradykinin or prostaglandin D2 (PGD2) to determine bronchial responsiveness [provocative concentration of agonist required to produce a 20% fall in forced expiratory volume in 1 s from the postdiluent baseline (PC20)]. Pretreatment with BAY u 3405 caused a twofold doubling-dilution reduction in bronchial reactivity to PGD2; the geometric mean PC20 values were 0.132 (0.015-0.871) and 0.034 (0.008-0.095) mg/ml, respectively, for active and placebo days (P = 0.001). There was, however, no significant difference in PC20 values for bradykinin between active and placebo treatment days. We have demonstrated that BAY u 3405 caused a significant inhibition of bronchconstriction induced by inhaled PGD2 but had no influence on bronchial responsiveness to inhaled bradykinin. This study suggests therefore that TxA2 receptors do not play a role in bradykinin-induced bronchoconstriction in asthma.

Adult↗

Value of a screening fetal heart rate tracing in the latent phase of labor.

We studied the value of a screening fetal heart rate (FHR) tracing obtained on 405 women in the latent phase of labor on presentation to the labor-and-delivery suite. All pregnancies were at term and had a cephalic presentation. Thirty-two women in the sample studied underwent a cesarean section for fetal distress. Using that end point, a screening FHR tracing in the admitting room had a sensitivity of 57%, specificity of 98%, positive predictive value of 75% and overall efficiency of 95%. One- and five-minute Apgar scores and thick meconium staining of the amniotic fluid were also examined. While no statistically significant differences were found (P less than .2 for Apgar score and less than .06 for meconium), there was a trend that might have been significant if more women had been studied. A screening FHR tracing on all women at term in the latent phase of labor will identify the majority of those who will develop fetal distress in labor. Women with an abnormal screening tracing should be admitted to the hospital and the fetal status evaluated further.

Female↗

Pregnancy surveillance with Doppler velocimetry of uterine and umbilical arteries.

Previous studies with Doppler velocimetry have demonstrated a strong correlation between abnormal waveforms and fetal-maternal disease. This study was designed to evaluate the potential role of Doppler velocimetry as a screening test in routine prenatal care. Two hundred fifty-five pregnant women had routine monthly Doppler (systolic/end-diastolic ratio) studies on the uterine and umbilical arteries starting in the twentieth week of gestation. When a cutoff value of 3 was used at 30 weeks for the umbilical arteries, there were 35 (13%) positive tests. In 20 of these values fell to less than 3 in the ensuing weeks and were considered false positive. The remaining 15 babies demonstrated positive clinical pathologic correlates. When a value of 2.6 was used at 26 weeks for uterine arteries, there were nine positive results, seven of which had clinical pathologic correlates. This study suggested an overall positivity rate of 7%; therefore it provides encouragement for a larger venture in which screening and impact on decision making are evaluated.

Adult↗

Vaginal delivery after cesarean section.

We retrospectively analyzed 194 pregnancies in women with a history of previous cesarean section (CS) who were offered a trial of labor. We offered every woman a trial of labor as long as she did not have a known previous classical scar. One hundred fifty-one women delivered vaginally (79%), 24 women had multiple uterine scars. Multiple gestations and breech presentation were not considered a sole indication to perform CS. Fetal and maternal morbidity are presented. We conclude that women with multiple previous CS scars can safely deliver vaginally as can women with unknown uterine scars, with careful intrapartum surveillance. Although our numbers of women with breech presentation and multiple gestations are small, in the absence of significant morbidity, we continue to allow these women to labor and deliver vaginally.

Cesarean Section↗

Upon-admission adrenal steroidogenesis is adapted to the degree of illness in intensive care unit patients.

Adrenal function was studied in 2 groups of intensive care unit (ICU) patients with varying degrees of illness, as determined by Acute Physiological and Chronic Health Evaluation (APACHE). The 15 seriously ill patients with high APACHE scores (greater than or equal to 25) had elevated Therapeutic Intervention Scores and increased mortality compared to the 15 ill patients (APACHE, less than or equal to 10; 67% vs. 27%). Plasma cortisol, aldosterone, and androstenedione concentrations were increased in the ICU patients compared to those in normal subjects (n = 23), being greater in the seriously ill patients. Plasma dehydroepiandrosterone sulfate (DHEAS) concentrations were low in both groups of ICU patients. The ratios of aldosterone or androstenedione to cortisol were not altered, whereas the DHEAS to cortisol ratios were reduced in the ICU patients. ACTH injection elicited increases in plasma cortisol, aldosterone, and androstenedione concentrations in both groups of ICU patients, and the ratios of aldosterone and androstenedione to cortisol did not change. In the seriously ill patients, plasma DHEAS increased, so that the DHEAS to cortisol ratio did not change, whereas in less ill patients plasma DHEAS did not increase, so that the DHEAS to cortisol ratio was reduced. In this study of patients admitted to an ICU, impairment of adrenal steroid secretion appears to be specific for DHEAS. Although plasma cortisol was elevated in ill patients proportional to the degree of illness, the contribution of the concomitant decrease in DHEAS to this increase is not clear.

Adrenal Glands↗

Prenatal surveillance using nonstress testing and Doppler velocimetry.

One hundred forty pregnant women referred to our prenatal testing laboratory for conventional nonstress testing (NST) also had a Doppler study of the umbilical arteries. The outcomes of 88 women with abnormal testing (NST or Doppler) were compared with the outcomes of 52 women who had normal results on both tests. The results demonstrated that 50% of the fetuses with decreased flow velocity who later developed an abnormal NST were growth-retarded, 75% required a cesarean section, and 63% were admitted to the neonatal intensive care unit. Development of an abnormal NST in the presence of normal velocimetry studies occurred most frequently in the postdates pregnancy; 32% required cesarean section for fetal distress. Knowledge of the umbilical circulation through Doppler studies may be of benefit when selecting patients for NST and when interpreting results.

Blood Flow Velocity↗

Uterine and umbilical artery Doppler velocimetry in postterm pregnancy.

Uterine and umbilical artery Doppler velocimetry was carried out on 149 women whose pregnancies went to 41 weeks or beyond. Flow velocity was not altered even in the presence of other signs suggestive of fetal compromise. It appears that the postdate syndrome is not associated with significant alterations in the maternal or umbilical blood flow prior to the onset of labor.

Arteries↗

The significance of absent end-diastolic velocity in umbilical artery velocity waveforms.

Doppler umbilical artery velocimetry has been used to study high-risk pregnancies. The most extreme waveform abnormality is the absence of end-diastolic velocity. To examine the significance of this finding, events outcome was evaluated in 161 women studied between 31 and 36 weeks. Ten had absence of end-diastolic velocity. When compared with fetuses with normal and less severely abnormal waveforms, there was a higher incidence of intrauterine growth retardation, pregnancy-induced hypertension, cesarean section for fetal distress, neonatal intensive care unit admission, and low Apgar scores. Average birth weight and gestational age at delivery were lower. Five other fetuses with absence of end-diastolic velocity were identified that were delivered between 27 and 30 weeks, making a total of 15 patients with absence of end-diastolic velocity. Of 12 patients monitored, 11 had an abnormal fetal heart rate pattern. Four fetuses had lethal anomalies. There were eight perinatal deaths. Acute or chronic hypoxia was evident in all fetuses with absence of end-diastolic velocity. Absent end-diastolic velocity represents a unique and severe fetal condition that cannot be identified by present surveillance methods and requires a Doppler study for diagnosis.

Blood Flow Velocity↗

Uterine-umbilical velocimetry in open heart surgery.

The effect of the nonpulsating cardiac pump in uterine and umbilical circulation has not been studied extensively by measuring the resistance of the uterine and umbilical circulation with velocimetry. During open heart surgery, we were able to demonstrate the effects of the nonpulsatile cardiac pump.

Adult↗

The clinical significance of Doppler umbilical artery velocimetry in the small for gestational age fetus.

Fifty-four women who were delivered of small for gestational age infants were studied antenatally by serially continuous-wave Doppler velocimetry. Outcomes were compared in the normal and abnormal systolic/diastolic ratio groups. Seventy-eight percent had an abnormal systolic/diastolic ratio. The group with an elevated systolic/diastolic ratio had a significantly higher incidence of abnormal fetal heart rate, pregnancy-induced hypertension, oligohydramnios, cesarean section for fetal distress, and admission into the neonatal intensive care unit. One third of the newborns required intermittent positive pressure ventilation. Average birth weight and gestational age at delivery were significantly lower and there were six perinatal deaths in the group with an elevated systolic/diastolic ratio and none in the group with a normal systolic/diastolic ratio. These data suggest that the small for gestational age fetus with normal umbilical artery velocimetry is at significantly lower risk than are those with abnormal ratios. This implies that management of the small for gestational age fetus may now be aided by a functional classification based on the umbilical artery velocity waveform.

Blood Flow Velocity↗

A classification of hypertension in pregnancy based on Doppler velocimetry.

We studied 136 pregnant women with hypertension with Doppler velocimetry of the uterine and umbilical arteries. The patients were classified into four groups according to the values of the systolic/diastolic ratios. The first group had normal ratios in both the umbilical and uterine arteries. The second group had elevated umbilical ratios and normal ratios in the uterine arteries. The third group had elevated uterine artery systolic/diastolic ratios with normal umbilical artery values, and the fourth group had elevated systolic/diastolic ratios in both vessels. Women in the group with normal ratios in both the umbilical and uterine arteries were delivered of infants with a birth weight (mean +/- SD) of 3261 +/- 522 gm and gestational age of 39 +/- 2 weeks. The values for the three groups with abnormal velocimetry were: those with elevated umbilical ratios and normal ratios in the uterine arteries: body weight = 2098 +/- 811 gm, gestational age = 35.7 +/- 3.2 weeks; those with elevated uterine artery ratios with normal umbilical artery values: 2464 +/- 722 gm, gestational age = 36.3 +/- 3 weeks; and those with elevated systolic/diastolic ratios in both vessels: body weight = 1627 +/- 697 gm, gestational age = 33.3 +/- 2.7 weeks (p less than 0.01; p less than 0.001). There were 27 small for gestational age infants delivered during this study. Doppler velocimetry studies were abnormal in 26 of them (96%). Results show that Doppler-derived vascular patterns correlate well with normal and adverse perinatal outcome. A description of the uterine and umbilical systolic/diastolic ratios should be part of the clinical evaluation of all pregnant women with hypertension. This should lead to better treatment protocols and improved clinical outcome.

Adult↗

Uterine artery Doppler velocimetry: the significance of divergent systolic/diastolic ratios.

Continuous wave Doppler studies were carried out on both uterine arteries in 71 pregnant women from the twentieth week of gestation onward. Analysis of the waveform included the systolic/diastolic ratio and the presence or absence of a diastolic notch. In the current study, these ratios from 31 women with left/right systolic/diastolic difference, (between left and right uterine arteries) were compared with those of women having normal ratios. A normal left/right systolic/diastolic ratio difference of 0.3 with SD of 0.3 was found. When the left/right difference was plotted against the left/right averaged systolic/diastolic ratio, a correlation coefficient of 0.7 was noted (p less than 0.001). Significant outcome differences were noted between normal and abnormal left/right difference systolic/diastolic ratios in the perinatal parameters of gestational age at delivery, fetal weight, pregnancy-induced hypertension, proteinuria, and intrauterine growth retardation. Divergent uterine artery ratio findings are a result of one artery being the dominant supplier to the placenta. The majority of women with an elevated systolic/diastolic ratio seem to have divergent uterine blood supply to the uterus and placenta. These data suggest that errors in placentation site contribute to the development of preeclampsia and growth retardation in the fetus.

Arteries↗