PubMed Health⌕ Search

Biomedical subjects

W F O'Brien

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

At least 109 records · Page 6Linked to original sources
PubMed1987

A group B streptococcal extract reduces neutrophil counts and induces neutrophil aggregation.

The possibility that group B streptococci (GBS) may induce neonatal neutropenia by promoting neutrophil aggregation and the entrapment of aggregates in the lung was studied in vivo and in vitro utilizing a cell free GBS extract [(GBS)-trichloroacetic acid (TCA)]. The intravenous infusion of the extract into neonatal lambs induced reductions of circulating white blood cells (0 time, 3.1 X 10(3)/mm3 +/- 0.5 versus 2.2 X 10(3)/mm3 +/- 0.7) 5 min after infusion (p less than 0.01). At necropsy these lambs had prominent accumulation of polymorphonuclear leukocytes in their pulmonary interstitium. Subsequently, neutrophil aggregation was studied by incubating GBS-TCA in human serum or phosphate-buffered saline with subsequent addition to human polymorphonuclear leukocytes in an aggregometer. GBS-TCA incubated in human serum induced prompt polymorphonuclear leukocyte aggregation (mean delta T 12.3% +/- 2.8 in human serum versus delta T 2.5% +/- 2.1 in phosphate-buffered saline, p less than 0.001). Preincubation of GBS-TCA followed by incubation in human serum with human GBS hyperimmune IgG significantly reduced aggregation (GBS-TCA in serum mean delta T 14.9 +/- 2.44 versus 5.42 +/- 1.80, p = 0.002). Cell-free GBS products may induce polymorphonuclear leukocyte aggregation in the presence of whole serum. This phenomenon might contribute to the pulmonary injury experienced by infants with GBS pneumonia and sepsis.

Animals↗
PubMed1987

Platelet inhibitory activity in placentas from normal and abnormal pregnancies.

Retroplacental blood flow requires inhibition of coagulation in the absence of an endothelial lining. We confirmed that trophoblast releases an inhibitor of platelet aggregation which functions via degradation of adenosine diphosphate. This inhibitor appears to be deficient in some pregnancies with abruptio placentae and intrauterine growth retardation. Unimpeded retroplacental blood flow may depend upon the local inhibition of platelet aggregation. Placental tissue contains an inhibitor of platelet aggregation which appears to be an adenosine diphosphatase distinct from heat-stable alkaline phosphatase. Placental tissue from patients with abruptio placentae contains abnormally low amounts of this enzyme.

Abruptio Placentae↗
PubMed1986

Psychiatric rehabilitation: past myths and current realities.

Psychiatric rehabilitation treatment has a unique and complementary contribution to make to the treatment of persons with a severe psychiatric disability. However, the development of the psychiatric rehabilitation field, and the adoption of its philosophy and techniques by mental health agencies, has been hampered by past myths. Research carried out in the 1960s and 1970s has exposed these myths as a part of the past, no longer relevant to the present practice of rehabilitating persons with severe psychiatric disabilities.

Combined Modality Therapy↗
PubMed1986

Alterations in platelet concentration and aggregation in normal pregnancy and preeclampsia.

Platelets were evaluated in normal pregnant women and in pregnant subjects with mild and severe preeclampsia, nonpregnant control subjects, and pregnant subjects with chronic hypertension. The parameters studied included platelet count, presence of circulating platelet aggregates, and in vitro platelet aggregability by means of a variety of agonists of platelet aggregation. When subjects with a normal pregnancy were compared to nonpregnant controls, they demonstrated a significantly lower platelet count and an increase in circulating platelet aggregates and in vitro hypoaggregability. Significant differences among the groups of pregnant subjects could not be found. These studies suggest the occurrence of platelet activation in pregnancy. This activation causes in vivo platelet aggregation followed by exhaustion of platelets.

Adolescent↗
PubMed1986

Plasma prostaglandin metabolite levels after use of prostaglandin E2 gel for cervical ripening.

An ideal agent for cervical ripening should produce an increase in cervical scores without stimulating myometrial contractions. Currently used methods of preinduction ripening with prostaglandin E2 are frequently associated with contractions, limiting their use in high-risk patients. To discriminate between a direct effect of absorbed prostaglandin E2 and a triggering of the intrinsic mechanisms of labor, we measured circulating levels of stable metabolites of prostaglandin E2 and prostaglandin F2 alpha. Prostaglandin E2 gel insertion followed by a rise in prostaglandin E2 metabolite but not prostaglandin F2 alpha metabolite implies that contractions are secondary to absorbed prostaglandin E2.

Dinoprost↗
PubMed1986

Cesarean delivery of the second twin after vaginal delivery of the first twin.

Cesarean birth of twin B after the vaginal delivery of twin A is an infrequent event. There is little information in the literature documenting outcome of vaginal-abdominal delivery. We reviewed our 10-year experience in the management of such cases and compared outcomes with twins delivered by repeat cesarean section and vaginal delivery in the same time period. Twenty-one cases of combined vaginal-cesarean section deliveries were managed at our institute in a 10-year period. There was no apparent increase in maternal and perinatal morbidity and mortality when twin B was delivered by cesarean section after vaginal delivery of twin A.

Apgar Score↗
PubMed1986

Birth weight in twins: an analysis of discordancy and growth retardation.

Sonographic estimation of fetal weight offers the potential of antenatal diagnosis of discordancy and growth retardation in twins. Although standards for intertwin birth weight percent differences in infants over 2500 g are available, similar norms are not available at lower weights. Intertwin birth weight percent differences in live-born twins above 500 g in 500-g increments were analyzed. Intertwin birth weight differences, expressed as a percentage of the weight of the larger twin, were relatively uniform across a wide range of birth weights. Differences above 15% were increasingly more likely to be associated with growth retardation in one of the infants.

Apgar Score↗
PubMed1986

Plasma and amniotic fluid concentrations of fibronectin during normal pregnancy.

To ascertain the influence of pregnancy on plasma concentrations of fibronectin, we quantified plasma concentrations of fibronectin in 22 normal, pregnant women during the first, second, and third trimesters; at the time of delivery; and at six weeks and eight months postpartum, using a rapid, immunoturbidimetric procedure. Mean plasma concentrations of fibronectin rose significantly throughout pregnancy, and were significantly greater than umbilical cord plasma concentrations. Maternal plasma concentrations of fibronectin at six weeks postpartum were similar to those observed at the time of delivery, but returned to concentrations observed in nonpregnant women by eight months postpartum. No significant differences between concentrations of fibronectin in amniotic fluid obtained during the second and third trimesters of pregnancy were observed. Six-week postpartum values appeared to depend upon the type of infant feeding as values rose in bottle feeding but fell in breast-feeding mothers.

Adolescent↗
PubMed1985

The effect of serotonergic blockade in postpartum preeclamptic patients.

Thirty postpartum preeclamptic patients from the University of South Florida Obstetrical Service were enrolled in a placebo-controlled, randomized, double-blind study to test the effectiveness of ketanserin in lowering the blood pressure. An intravenous bolus of ketanserin resulted in a significant drop in the mean arterial blood pressure. The decrease in the blood pressure could be maintained by a continuous infusion of ketanserin. Hypertension returned after the medication was discontinued. These observations suggest that ketanserin, a selective blocker of type II serotonin receptors, may be effective in acutely reducing elevated postpartum blood pressure in preeclamptic patients, and that serotonin may play a role in the pathogenesis of preeclampsia, but not be important as a mediator in the severity of the disease.

Adult↗
PubMed1985

Endotoxemia in the neonatal lamb.

Although gram-negative sepsis is a major cause of neonatal morbidity and mortality, our understanding of endotoxemia in the neonate has been hampered by the lack of experimental models. Previous studies have suggested neonatal hyporesponsiveness to endotoxin. We studied unanesthetized neonatal lambs which had been exposed to the environment prior to study. These animals demonstrated the classic early phase changes of endotoxemia including pulmonary hypertension which was dependent upon prostanoid production. This model allows further studies of endotoxemia in the neonate.

Animals↗
PubMed1985

Effect of maternal intravenous infusions on fetal extracellular fluid composition in pregnant ewes.

Infusion of intravenous solutions to women in labor is common clinical practice. Since these infusions may change the volume and electrolyte balance between the mother and fetus, we investigated the influence of acute maternal volume expansion upon fetal and maternal fluid and electrolyte equilibrium in the chronically catheterized fetal lamb. Paired measurements of maternal and fetal plasma sodium and potassium concentrations, osmolality, and colloid osmotic pressure (COP), plus measurements in the fetal-placental plasma volume were obtained following rapid maternal infusions with saline, dextrose, and dextran solutions. Maternal infusions resulted in changes in fetal electrolyte concentrations as well as alterations in transplacental COP differences. Despite these changes, however, no changes in fetal plasma volume were noted.

Animals↗
PubMed1985

Short-term responses in neonatal lambs after infusion of group B streptococcal extract.

Short-term (0 to 30 minutes) physiologic responses of neonatal lambs infused with a trichloroacetic extract of a type III (strain 878) group B streptococcus (878-TCA) were studied. Bolus injections of 878-TCA were associated with pulmonary hypertension, peripheral arterial hypoxemia, and reductions in circulating white blood cell and platelet counts. These events were associated with a rise in plasma levels of prostaglandins F2 alpha and E and could be prevented by proper treatment with ibuprofen. Continuous infusions of 878-TCA were associated with a dose-dependent rise in systemic and pulmonary arterial pressures and a fall in arterial PO2. During infusion, inhibition of prostaglandin synthesis resulted in a return toward preinfusion values. The authors conclude that venous infusions of extracts of 878-TCA induce significant pulmonary and systemic arterial vascular perturbations in the neonatal lamb and that some of these alterations are associated with the release of prostaglandins or other arachidonic acid metabolites.

Animals↗
PubMed1985

Use of prostaglandin E2 topical cervical gel in high-risk patients: a critical analysis.

This investigation compared the safety and efficacy of 3- and 5-mg doses of prostaglandin E2 topical gel used for cervical ripening in 60 high-risk obstetric patients before oxytocin induction of labor. Both dosages significantly increased the Bishop score, unrelated to parity or gestational age. Induction time was significantly shortened, and the average maximum amount of oxytocin required was significantly less with the 5-mg dose, but not with the 3-mg dose, when compared with a placebo. Prostaglandin E2 did not influence the cesarean section rate. Uterine contractions were stimulated in 87.5% of the patients who received the drug, and 37.5% went into active labor, suggesting that prostaglandin E2 in these dosages is not an appropriate agent for local cervical ripening.

Administration, Topical↗
PubMed1985

Intrauterine fetal death in twins after 32 weeks of gestation.

A retrospective review of the outcome in multifetal pregnancies from January 1, 1980 to July 31, 1983 was undertaken to evaluate the role of nonstress test, followed by contraction stress test when indicated, in reduction of intrauterine fetal deaths in twins after 32 weeks of gestation. Of the 90 twin pregnancies managed under the authors' protocol, there were no intrauterine fetal deaths. Intervention leading to delivery occurred in six twin pregnancies with an abnormal nonstress test followed by an equivocal or positive contraction stress test. The authors believe that routine use of weekly nonstress tests after 30 weeks of gestation coupled with contraction stress tests when indicated, and use of other parameters of fetal assessments such as ultrasound, intrauterine fetal death in twin gestation after 32 weeks of gestation, can be significantly reduced.

Evaluation Studies as Topic↗
PubMed1984

Rhesus isoimmunization in twin gestation.

The incidence of Rh isoimmunized twin gestation is extremely low. There are several perinatal risks inherent to twinning. Rhesus isoimmunization further increases hazards of such a compromised gestation. This paper reports three cases of rhesus isoimmunization in twin gestation, discusses the selective problems of such pregnancies, and reviews the pertinent literature.

Amniocentesis↗