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Biomedical subjects

R K Creasy

Publications and source records attributed to R K Creasy.

At least 55 records · Page 3Linked to original sources
PubMed1984

Cardiovascular consequences of beta-agonist tocolysis: an echocardiographic study.

M-mode echocardiography was performed before and during intravenous beta-adrenergic agonist tocolysis in 13 patients with preterm labor. There was a significant increase in heart rate, fractional shortening, and calculated cardiac output. There was also a significant decrease in both end-systolic and end-diastolic left ventricular dimensions, which resolved in 24 to 36 hours. There were, however, no changes in left atrial dimensions. The data derived from this study suggest that the pulmonary edema occasionally complicating beta-adrenergic agonist tocolysis is not the result of systolic cardiac dysfunction.

Adrenergic beta-Agonists↗
PubMed1984

Obstetric management of the growth retarded baby.

Identification and modification of potential risk factors, early diagnosis, intensive prenatal surveillance, and appropriate, timely intervention is necessary for successful management of the pregnancy complicated by intrauterine growth retardation. Once an antepartum diagnosis of fetal growth retardation has been made, extensive evaluation including a thorough ultrasound examination and amniocentesis (if technically possible) for fetal lung profile studies and karyotype is indicated. Intensive fetal surveillance with nonstressed testing (in the absence of oligohydramnios) or contraction stress testing on a weekly basis (if normal) can usually assure one of fetal well being. A combination of NST/CST testing may increase the effectiveness of predicting perinatal morbidity. Daily increasing serial oestriol urinary values may be of some benefit in assuring fetal well being. Serial sonography to assess amniotic fluid volume and interval fetal growth is important. Use of the biophysical profile may significantly improve the perinatal outcome, but substantiation in a large group of growth retarded infants is lacking. Delay of delivery until 37-38 weeks' gestational age (or, in the hypertensive patient, until fetal lung maturity is documented) currently appears optimal. However, in the face of fetal surveillance testing suggesting a deterioration in fetal status or lack of interval growth, delivery should be undertaken. The mode of delivery will depend rather on the indication for intervention. Caesarean section should be seriously considered in many cases of intrauterine growth retardation. At the time of delivery, the paediatric team should always be present and ready to resuscitate the infant if necessary and to anticipate potential problems associated with the growth retarded fetus.

Amniotic Fluid↗
PubMed1984

Heterotopic skin in the uterus. A report of an unusual case.

A case occurred of heterotopic skin in the uterus, with hair protruding from the cervix. The patient was on immunosuppressive therapy and 30 months earlier had undergone pregnancy termination at 14 weeks. Microscopic examination revealed a single endometrial polyp composed of mature squamous epithelium, adnexal structures and terminal hairs. Previous reports have been published on heterotopic tissue of all types in the uterus, and three hypotheses about their origin have been offered.

Adult↗
PubMed1983

Methods of cervical priming.

It is now well recognized that a priming agent without untoward effects on mother or fetus is highly desirable when an indicated induction is required in the face of an unripe cervix. There appears to be a potential role for Laminaria, estrogens, relaxin, and various forms and routes of administration of prostaglandins because efficacy has been reported with all of these methods. With careful selection of patients and judicious fetal monitoring, there are multiple reasonable modes available, although an ideal priming agent has not yet emerged.

Administration, Oral↗
PubMed1983

Cardiovascular responses to alpha-melanocyte stimulating hormone during the perinatal period in sheep.

To determine the effects of alpha-melanocyte stimulating hormone (alpha MSH) on the circulation of undisturbed fetal sheep and young lambs and to explore possible mechanisms of actions, we examined the responses of ascending aortic blood flow, heart rate, stroke volume, and arterial blood pressure to a single intravenous injection of alpha MSH, ACTH, cortisol and to alpha MSH after beta-adrenergic blockade. We also measured cardiac output and organ blood flows before and after alpha MSH injection by the radionuclide labeled microsphere technique. alpha MSH increased ascending aortic blood flow from 249 +/- 23 to 327 +/- 30 ml X min-1 X kg-1 (P less than 0.001), heart rate from 111 +/- 10 to 126 +/- 11 min-1, (P less than 0.001) and stroke volume from 2.32 +/- 0.21 to 2.75 +/- 0.20 ml X kg-1, (P less than 0.001) in 10 young lambs 15-30-day-old. alpha MSH decreased mean systemic arterial blood pressure from 42.6 +/- 1.7 to 39.3 +/- 1.6 mmHg (P less than 0.001) in fetal sheep and min-1, (P less than 0.001) and stroke volume from 2.32 +/- 0.21 to 2.75 +/- 0.20 ml X kg-1, (P less than 0.001) in 10 young lambs 15-30-days-old. alpha MSH decreased mean systemic arterial blood pressure from 42.6 +/- 1.7 to 39.3 +/- 1.6 mmHg (P less than 0.001) in fetal sheep and from 77.5 +/- 4.5 to 72.7 +/- 4.3 mmHg (P less than 0.001) in young lambs. In six additional young lambs (20-35-day-old) cardiac output, measured by microspheres, increased with alpha MSH from 216 +/- 20 to 261 +/- 19 ml X min-1 X kg-1 (P less than 0.001). alpha MSH also increased blood flow to the myocardium from 104 +/- 22 to 151 +/- 26 ml X min-1 X 100 g-1 (P less than 0.001), to the adrenals from 195 +/- 38 to 243 +/- 41 ml X min-1 X 100 g-1, (P less than 0.05), and to the lungs from 157 +/- 31 to 468 +/- 81 ml X min-1 X 100 g-1 (P less than 0.005).(ABSTRACT TRUNCATED AT 250 WORDS)

Adrenocorticotropic Hormone↗
PubMed1982

Cardiovascular and mammary blood flow alterations during pregnancy and nursing in the rabbit.

The changes in cardiac output, pulse rate, mean arterial pressure, and mammary blood flow were observed during pregnancy and nursing in a chronically instrumented rabbit preparation. Nursing and suckling were found to be associated with significant changes in cardiac output and mammary blood flow. These changes included a progressive increase in cardiac output during pregnancy. In addition, nursing animals had a significantly higher cardiac output than did nonnursing animals. Mammary blood flow was found to increase significantly prior to delivery and reached peak values at 2 weeks after delivery. The relationship between these changes and variables such as litter size, hormonal status, and puerperal stage is discussed in light of the possible physiologic mechanisms which control adaptation during nursing.

Animals↗
PubMed1982

Fetal growth and perinatal viability in California.

To produce more appropriate information for evaluating fetal growth and viability, vital records data were used to compute percentile curves and perinatal, neonatal, and fetal mortality rates at specific birth weights and gestational ages. Percentile values were in good agreement with previous studies, and the large number of births (2,288,806) allowed for a more precise determination of fetal viability at various weight-age combinations than has been previously available. Mortality rates were found to be much more sensitive to birth weight than to gestational age, especially for small-for-gestational age fetuses. Optimal weight-age combinations were found to be up to 500 g and 2 weeks greater than the average combination. The results consistently emphasize the importance of rapid and sustained fetal growth at all gestational ages.

Birth Weight↗
PubMed1982

Evaluation of a preterm birth prevention program: preliminary report.

A clinical study to determine the effectiveness of a program for prevention of preterm birth was conducted at the University of California, San Francisco. The program included scoring and assigning the patients according to their risk of having spontaneous preterm labor and delivery. Patients were instructed in self-detection of the early signs of preterm labor, and those at high risk were followed weekly in a special clinic. A second aspect of the program included intensive in-service education of the obstetric staff. The data indicate that during the year under review a significant decrease in the incidence of preterm delivery has occurred. It is suggested that the preterm birth prevention program may have been instrumental in reducing the preterm delivery rate by enabling early and effective long-term tocolytic therapy.

Female↗
PubMed1981

Uterine blood flow distribution after indomethacin infusion in the pregnant rabbit.

The distribution of uterine blood flow (UBF) in the chronically instrumented pregnant term rabbit was examined before and after indomethacin infusion. A significant fall in placental but not myometrial blood flow was observed. The fall in placental blood flow was significantly higher in placentas which were implanted in the midsection of the uterine horn than in those implanted in both ends of the horn. The results suggest that different physiologic mechanisms may regulate the blood flows in the placenta and the myometrium.

Animals↗
PubMed1981

Maternal morbidity associated with isoxsuprine and terbutaline tocolysis.

A retrospective study of 343 women treated with isoxsuprine and/or terbutaline for preterm labor (PTL) was performed to determine the incidence and nature of maternal morbidity which is associated with this treatment. The incidence of mild cardiovascular (CV), neurological and gastrointestinal side effects was similar with both medications. The incidence, however, of severe CV complications such as pulmonary edema and myocardial ischemia was higher among women treated with i.v. terbutaline (5.3%) than among those treated with isoxsuprine (0.8%, P less than 0.05). Patients with multiple gestations on i.v. terbutaline therapy had an exceptionally high incidence of severe CV complications (43%), while none of the twin pregnancies on i.v. isoxsuprine had such complications. Corticosteroid treatment was not associated with a significant increase of complications with either tocolytic medication. Both medications had similar success in inhibiting PTL.

Adult↗
PubMed1981

Prepartum maturation of the lung in fetal sheep: relation to cortisol.

We studied the relationship of certain fetal and maternal hormones to indicators of lung maturation in 12 fetal lambs delivered at gestational ages (GA) of 123-149 days. Maternal estrogen, maternal progesterone, and fetal prolactin did not correlate with GA or the indicators of fetal lung maturation. Fetal cortisol (range 4-165 ng X ml-1) increased with advancing GA (r = 0.747, P less than 0.01). All of the following showed a wide range of late gestation and showed a significant positive correlation with fetal cortisol: lung volumes at 40 cmH2O and 10 cmH2O on the deflation during air pressure-volume studies; saturated phosphatidylcholine (SPC) in lung tissue and in lavage fluid expressed both as mg X g-1 of wet lung and as percent of total phospholipids (%PL); total SPC (lung tissue plus lavage fluid): and SPC in lavage fluid as percent of total SPC. Lung DNA correlated inversely with GA and cortisol. All variables (except lavage fluid SPC as %PL) correlated more closely with cortisol than GA. Morphological development of lung was also related more closely to cortisol than GA. These results suggest that functional lung maturity is attained late in gestation and that endogenous cortisol is an important physiological factor in control of fetal lung maturation.

Animals↗
PubMed1981

Blood pressure and pressor response to angiotensin II during pregnancy and nursing in the rabbit.

A continuous study to determine blood pressure and pressor response to angiotensin II (A-2) during pregnancy and postpartum was performed in a chronic rabbit preparation. The resting blood pressure during pregnancy was found to be lower than that in the postpartum period. Pressor response to A-2 was diminished during pregnancy and during nursing, but in the absence of nursing, this response returned to normal values by 1 week postpartum. Inhibition of prostaglandin synthetase caused a significant increase in the pressor response to A-2 during gestation, but did not change the resting blood pressure either before or after delivery. The results are discussed in light of previous animal and human studies, and factors which could affect vascular reactivity during gestation and nursing are analyzed.

Angiotensin II↗
PubMed1981

Pulmonary maturation in the hypophysectomised ovine fetus. Differential responses to adrenocorticotrophin and cortisol.

Pulmonary maturation in six ovine fetuses hypophysectomised by a cryosurgical method at 0.7-0.8 of pregnancy and delivered by hysterotomy at 152.2 +/- 2.9 (SD) days was compared with that in seven control fetuses delivered at 144.5 +/- 3.5 days. Both the wet and the dry weight of the lungs was less in the hypophysectomised fetuses but total DNA did not differ. Lung volumes at 40 cm of H2O and at 5 cm of H2O on deflation in hypophysectomised fetuses were less than one-third that of controls. Saturated phosphatidylcholine, as an estimate of surfactant, was lower in both lung tissue and lavage fluid. A further group of hypophysectomised fetuses was infused intravenously either with cortisol at 1 mg/h for 72 h (n = 6), or with ACTH1-24 at 5 microgram/h for 84 h (n = 6) before delivery at 155.0 +/- 2.1 days and 154.2 +/- 3.9 days respectively. None of the indices of pulmonary maturation in the cortisol-treated fetuses differed from those in untreated hypophysectomised fetuses whereas values for lung volumes at 40 and 5 cm of H2O in ACTH-treated fetuses were more than twice those of untreated hypophysectomised fetuses and did not differ significantly from controls. In addition, the amount of saturated phosphatidylcholine in lavage fluid was greater in ACTH-treated fetuses (0.13 +/- 0.10 mg/g) than in untreated hypophysectomised fetuses (0.04 +/- 0.48 mg/g). Lung volume at 40 cm of H2O in four fetuses that were thyroidectomised at the time of hypophysectomy responded to ACTH as in hypophysectomised fetuses with intact thyroids but other indices were unaffected. We conclude that hypophysectomy retards pulmonary maturation in fetal sheep. Since ACTH restores distensibility and increases alveolar surfactant in the absence of other pituitary hormones it is likely that ACTH has a major role in lung maturation. The lack of response to cortisol suggests that the effect of ACTH is not mediated only by circulating cortisol.

Adrenocorticotropic Hormone↗