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Biomedical subjects

J M Crane

Publications and source records attributed to J M Crane.

At least 19 recordsLinked to original sources
PubMed2002

The development of a genetic map for meadowfoam comprised of amplified fragment length polymorphisms.

Limnanthes alba Benth. (meadowfoam), a diploid ( x=5) winter annual, produces novel very long-chain seed oils (C(20) and C(22)) with less than 2% saturated fatty acids. The first genetic map of meadowfoam, a recently domesticated species, is described herein. Two phenotypically diverse inbred lines, OMF40-11 ( L. alba ssp. alba) and OMF64 ( L. alba ssp. versicolor), were screened for amplified fragment length polymorphisms (AFLPs) using 16 primer combinations. Twenty three percent of the AFLP bands (415 out of 1,801) were polymorphic between OMF40-11 and OMF64. One hundred (OMF40-11xOMF64)xOMF64 BC(1) progeny were genotyped for 107 polymorphic AFLP markers produced by nine AFLP primer combinations. One hundred and three AFLP loci amalgamated into five linkage groups with 14 to 28 loci per linkage group (four loci segregated independently). The map was 698.5-cM long with a mean interlocus spacing of 6.7 cM and no dense clustering of loci. The segregation ratios for 25 loci (23.2%) were significantly distorted. Twenty one of the distorted loci (84%) had an excess of L. alba ssp. versicolor (recurrent parent) alleles. The distorted loci, apart from one locus on linkage group 4, were distally clustered on both ends of linkage groups 1, 4 and 5. The development of the map was facilitated by the small chromosome number, an abundance of restriction site polymorphisms between the two subspecies (23%), and a high multiplex ratio of the AFLP markers (112 per primer combination).

Journal Article↗
PubMed2001

Peptide mimics of SNARE transmembrane segments drive membrane fusion depending on their conformational plasticity.

SNARE proteins are essential for different types of intracellular membrane fusion. Whereas interaction between their cytoplasmic domains is held responsible for establishing membrane proximity, the role of the transmembrane segments in the fusion process is currently not clear. Here, we used an in vitro approach based on lipid mixing and electron microscopy to examine a potential fusogenic activity of the transmembrane segments. We show that the presence of synthetic peptides representing the transmembrane segments of the presynaptic soluble N-ethylmaleimide-sensitive factor attachment protein receptors (SNAREs) synaptobrevin II (also referred to as VAMP II) or syntaxin 1A, but not of an unrelated control peptide, in liposomal membranes drives their fusion. Liposome aggregation by millimolar Ca(2+) concentrations strongly potentiated the effect of the peptides; this indicates that juxtaposition of the bilayers favours their fusion in the absence of the cytoplasmic SNARE domains. Peptide-driven fusion is reminiscent of natural membrane fusion, since it was suppressed by lysolipid and involved both bilayer leaflets. This suggests transient presence of a hemifusion intermediate followed by complete membrane merger. Structural studies of the peptides in lipid bilayers performed by Fourier transform infrared spectroscopy indicated mixtures of alpha-helical and beta-sheet conformations. In isotropic solution, circular dichroism spectroscopy showed the peptides to exist in a concentration-dependent equilibrium of alpha-helical and beta-sheet structures. Interestingly, the fusogenic activity decreased with increasing stability of the alpha-helical solution structure for a panel of variant peptides. Thus, structural plasticity of transmembrane segments may be important for SNARE protein function at a late step in membrane fusion.

Amino Acid Sequence↗
PubMed2001

Rapid compression transforms interfacial monolayers of pulmonary surfactant.

Films of pulmonary surfactant in the lung are metastable at surface pressures well above the equilibrium spreading pressure of 45 mN/m but commonly collapse at that pressure when compressed in vitro. The studies reported here determined the effect of compression rate on the ability of monolayers containing extracted calf surfactant at 37 degrees C to maintain very high surface pressures on the continuous interface of a captive bubble. Increasing the rate from 2 A(2)/phospholipid/min (i.e., 3% of (initial area at 40 mN/m)/min) to 23%/s produced only transient increases to 48 mN/m. Above a threshold rate of 32%/s, however, surface pressures reached > 68 mN/m. After the rapid compression, static films maintained surface pressures within +/- 1 mN/m both at these maximum values and at lower pressures following expansion at < 5%/min to > or = 45 mN/m. Experiments with dimyristoyl phosphatidylcholine at 37 degrees C produced similar results. These findings indicate that compression at rates comparable to values in the lungs can transform at least some phospholipid monolayers from a form that collapses readily at the equilibrium spreading pressure to one that is metastable for prolonged periods at higher pressures. Our results also suggest that transformation of surfactant films can occur without refinement of their composition.

Animals↗
PubMed2001

Excessive uterine activity accompanying induced labor.

OBJECTIVE: To estimate the incidence and timing of excessive uterine activity accompanying induction of labor with misoprostol using different routes (oral or vaginal) and forms (intact tablet or crushed) and to compare these with dinoprostone gel, oxytocin, and spontaneous labor. METHODS: This retrospective cohort study included 519 women at term who had labor induced and 86 women at term in spontaneous labor. Induction agents included misoprostol, dinoprostone, or oxytocin. Fetal heart rate and uterine activity tracings were analyzed independently by three maternal-fetal medicine physicians. The diagnosis of tachysystole or hyperstimulation required the agreement of two or more reviewers. RESULTS: The incidence of tachysystole was highest with misoprostol administered by vaginal tablet (misoprostol vaginal tablet 50 microg every 4 hours, 48.6%; vaginal tablet crushed 50 microg and suspended in hydroxyethyl gel every 4 hours, 30.7%, P =.009; oral tablet 50 microg every 4 hours, 22.2%, P =.001; oral tablet crushed 50 microg every 4 hours, 15.5%, P <.001; dinoprostone gel, 33.0%, P =.022; intravenous oxytocin, 30.2%, P =.027; and spontaneous onset of labor, 23.3%, P <.001). Hyperstimulation occurred more often with dinoprostone gel (16.5%) than with other forms of induction or spontaneous labor. Hyperstimulation occurred significantly more often with vaginal misoprostol crushed tablet (7.9%) and vaginal misoprostol intact tablet (7.6%) than with crushed oral misoprostol (1.0%) (P =.016 and.018, respectively). There was a shorter time to tachysystole with increasing doses of vaginal misoprostol tablet (P =.01). CONCLUSION: The incidence of tachysystole and hyperstimulation, and time to tachysystole, varied depending on the route and form of misoprostol given.

Administration, Intravaginal↗
PubMed2001

Transvaginal ultrasound and digital examination in predicting successful labor induction.

OBJECTIVE: To compare transvaginal ultrasound and digital cervical examination in predicting successful induction in post-term pregnancy. METHODS: Transvaginal ultrasound and digital vaginal examinations were performed on 122 women at 41 or more weeks' gestation, immediately before labor induction. Ultrasound assessments of cervical length, dilatation, and presence of funneling were compared with the components of the Bishop score. The primary outcome was the rate of vaginal delivery. Secondary outcomes assessed included the rates of active labor in 12 hours, vaginal delivery in 12 and 24 hours, mean duration of latent phase, and induction to vaginal delivery interval. Linear and multiple logistic regression models were generated to identify factors independently associated with successful induction. RESULTS: No ultrasound characteristic predicted primary or secondary outcomes. Bishop score (odds ratio [OR] 2.98, 95% confidence interval [CI] 1.71, 5.20), cervical position (OR 4.35, 95% CI 1.41, 12.50), and maternal age (OR 1.15, 95% CI 1.01, 1.30) independently predicted vaginal delivery. Maternal weight (OR 0.96, 95% CI 0.94, 0.98), cervical dilatation (OR 6.08, 95% CI 1.70, 21.68), and effacement (OR 2.34, 95% CI 1.16, 4.73) independently predicted active labor in 12 hours. Independent predictors of vaginal delivery in 12 hours were induction method (P <.001), cervical dilatation (OR 11.16, 95% CI 3.17, 39.29), gravidity (OR 2.06, 95% CI 1.13, 3.77), and maternal weight (OR 0.96, 95% CI 0.93, 0.99). Cervical effacement (OR 2.70, 95% CI 1.59, 4.57) and parity (OR 7.10, 95% CI 2.22, 22.72) independently predicted vaginal delivery in 24 hours. Maternal weight, cervical position, and cervical dilatation were independently associated with latent phase labor duration. Factors independently associated with length of induction to delivery interval were parity, cervical effacement, and maternal weight. CONCLUSION: Transvaginal ultrasound does not predict successful labor induction in post-term pregnancy as well as digital cervical examination.

Adult↗
PubMed2001

Quality improvement efforts in oncology: are we ready to begin?

Large variations in the quality of cancer care are a matter of concern in the United States. Despite spending over 15% of our GNP on health care, more than any other country in the world, some cancer patients face significant risks of dying from their treatment precisely because of their choice of physician. The Institute of Medicine has reported that variations in the quality of cancer are large, and that low-experienced providers are more likely to provide a lower quality of medical care. Increased pressures to contain costs have led to concern that the quality and outcomes of cancer care may only worsen. One reaction to this situation is a greater reliance on "report cards." In an effort to address both quality and cost issues, providers are looking outside the health care sector for guidance for more acceptable alternatives to report cards, which are often viewed as punitive. The approach that they most often have selected recently is termed continuous quality improvement (CQI) or total quality management (TQM). In this article, we describe the potential benefits and drawbacks of CQI efforts in oncology, review experiences with four different CQI cancer programs, and make recommendations about future CQI efforts.

Medical Oncology↗
PubMed2000

Acardiac twin pregnancy with neonatal resolution of donor twin cardiomyopathy.

BACKGROUND: Twin reverse arterial perfusion, as with acardiac fetuses, is a rare complication of multifetal pregnancy. Prognosis of the donor twin is guarded because of the high risk of cardiac failure, polyhydramnios, and preterm delivery. CASE: A 40-year-old woman, gravida 4, para 3, was diagnosed at 19 weeks' gestation with a twin pregnancy complicated by an acardiac, acephalic fetus. Serial amniocenteses were done to decompress the hydramnios between 27 and 33 weeks. Ultrasonography showed ventricular septal hypertrophy in the donor twin at 27 weeks, and cesarean delivery was done at 33 weeks. The neonatal course was complicated by hypertrophic cardiomyopathy, which resolved without sequelae by 1 year of age. CONCLUSION: Antenatal sonographic monitoring of interventricular septal thickness can be a useful marker to predict neonatal cardiac sequelae.

Adult↗
PubMed2000

Successful intrauterine pregnancy after endometrial ablation.

The frequency of pregnancy after endometrial ablation is reported in the literature to be 0.7%, with a variety of complications and adverse outcomes for the fetus. A 30-year-old woman underwent rollerball endometrial ablation for menometrorrhagia. Her menses returned to normal and she conceived 16 months later. The pregnancy was uncomplicated apart from diet-controlled gestational diabetes and cesarean delivery for a transverse lie. To our knowledge, this is the first literature report of a viable pregnancy after rollerball ablation.

Adult↗
PubMed2000

Maternal complications with placenta previa.

The purpose of this study is to describe the maternal complications of placenta previa. A population-based retrospective cohort study including all women delivered in the province of Nova Scotia, Canada from 1988 to 1995 was performed. Patient information was obtained from the Nova Scotia Atlee Perinatal Database and maternal complications were described for all women undergoing cesarean delivery. Prognostic factors for the risk of hysterectomy in woman with placenta previa were analyzed by multiple logistic regression. During the 8-year period, 308 cases of placenta previa were identified in 93,996 deliveries (0.33%). Maternal complications included hysterectomy [relative risk (RR) = 33.26], antepartum bleeding (RR = 9.81), intrapartum (RR = 2.48), and postpartum (RR = 1.86) hemorrhages, as well as blood transfusion (RR = 10.05), septicemia (RR = 5.55), and thrombophlebitis (RR = 4.85). Risk factors for need of hysterectomy in women with placenta previa include the presence of placenta accreta and previous cesarean delivery.

Adult↗
PubMed2000

Sexuality and sexual activity in pregnancy.

OBJECTIVES: To evaluate women's sexual experience in pregnancy, and to describe their sources of information regarding sexuality during this period. DESIGN: Cross-sectional study. SETTING: The offices of obstetricians providing obstetric care in a tertiary care university hospital in St. John's, Newfoundland, Canada. POPULATION: One hundred and forty-one pregnant women. METHODS: Pregnant women anonymously completed self-administered questionnaires regarding sexuality and sexual activity during pregnancy. Responses were summarised using descriptive statistics, and comparisons were made between the trimesters of pregnancy. Multiple logistic regression was performed to assess the influences of a variety of factors on sexual activity. RESULTS: Vaginal intercourse and sexual activity overall decreased throughout pregnancy (P = 0.004 and 0.05, respectively) with the trimester of pregnancy being the only independent predictor. Most women reported a decrease in sexual desire (58%). Overall, 49% of women worried that sexual intercourse may harm the pregnancy. Concerns regarding sexual activity leading to preterm labour or premature rupture of membranes increased as the pregnancy progressed (P < 0-001 and P = 0-001, respectively). Only 29% of women discussed sexual activity in pregnancy with their doctor and 49% of these women raised the issue first, with 34% feeling uncomfortable in bringing up the topic themselves. Most women (76%) who had not discussed these issues with their doctor felt they should be discussed. CONCLUSIONS: A reduction in sexual activity, vaginal intercourse and sexual desire occurs in many women as pregnancy progresses. Both the woman and her partner have concerns regarding complications in the pregnancy as a result of sexual intercourse. The majority of women wish to discuss these issues with their doctor, but are not always comfortable raising the topic themselves.

Adult↗
PubMed2000

A double-blind placebo controlled randomised trial of misoprostol and oxytocin in the management of the third stage of labour.

OBJECTIVE: To compare oral misoprostol 400 microg with intramuscular oxytocin 10 IU in the routine management of the third stage. DESIGN: Double-blind placebo controlled trial. SETTING: Main referral hospital and its associated polyclinics in Accra, Ghana. POPULATION: Four hundred and one low risk women, in the second stage of labour with anticipated vaginal delivery, who entered labour spontaneously. METHODS: After delivery of the anterior shoulder of the baby, the women were randomised to receive either: 1. misoprostol 400 microg powder in water orally and 1 mL normal saline intramuscular injection (placebo); or 2. powdered cellulose in water orally (placebo) and 1 mL oxytocin 10 IU intramuscular injection. MAIN OUTCOME MEASURES: Change in haemoglobin concentration from before delivery to 12 hours postpartum. Secondary outcomes included need for additional oxytocics, blood loss > 500 mL and > 1,000 mL, operative intervention for postpartum haemorrhage, and side effects, including nausea, vomiting, diarrhoea, shivering and elevated temperature. RESULTS: Demographic characteristics were similar. There was no significant difference in change in haemoglobin concentration between the two groups (0.60 g/dL for misoprostol and 0.55 g/dL for oxytocin; relative difference 9.6%; 95% CI 20.5-39.6%; P = 0.54). There were no significant differences in secondary outcomes with the exception of shivering, which occurred more frequently in the misoprostol group (22.2% vs 5.7%; relative risk 4.73; 95% CI 2.31-9.68; P < 0.0001). CONCLUSIONS: In low risk women oral misoprostol appears to be as effective in minimising blood loss in the third stage of labour as intramuscular oxytocin. Shivering was noted more frequently with misoprostol use, but no other side effects were noted. Misoprostol has great potential for use in the third stage of labour especially in developing countries.

Administration, Oral↗
PubMed1999

Persistence of phase coexistence in disaturated phosphatidylcholine monolayers at high surface pressures.

Prior reports that the coexistence of the liquid-expanded (LE) and liquid-condensed (LC) phases in phospholipid monolayers terminates in a critical point have been compromised by experimental difficulties with Langmuir troughs at high surface pressures and temperatures. The studies reported here used the continuous interface of a captive bubble to minimize these problems during measurements of the phase behavior for monolayers containing the phosphatidylcholines with the four different possible combinations of palmitoyl and/or myristoyl acyl residues. Isothermal compression produced surface pressure-area curves for dipalmitoyl phosphatidylcholine (DPPC) that were indistinguishable from previously published data obtained with Langmuir troughs. During isobaric heating, a steep increase in molecular area corresponding to the main LC-LE phase transition persisted for all four compounds to 45 mN/m, at which collapse of the LE phase first occurred. No other discontinuities to suggest other phase transitions were apparent. Isobars for DPPC at higher pressures were complicated by collapse of the monolayer, but continued to show evidence up to 65 mN/m for at least the onset of the LC-LE transition. The persistence of the main phase transition to high surface pressures suggests that a critical point for these monolayers of disaturated phospholipids is either nonexistent or inaccessible at an air-water interface.

1,2-Dipalmitoylphosphatidylcholine↗
PubMed1999

Risk scoring, fetal fibronectin, and bacterial vaginosis to predict preterm delivery.

OBJECTIVE: To determine the value of markers for predicting spontaneous preterm birth. METHODS: One hundred forty asymptomatic gravidas were recruited from 20-24 weeks' gestation. Risk score was assessed, vaginal swabs were analyzed for bacterial vaginosis, and cervical and vaginal swab were tested for fetal fibronectin FDC-6, X18A4, and CAF. Univariate analysis was used to determine potential predictors (and combinations of predictors) of outcome. Multiple logistic regression was done to identify independent predictors of spontaneous preterm birth. Sensitivity, specificity, positive and negative predictive values; and odds and likelihood ratios were calculated for significant predictors. RESULTS: Predictors significantly associated with the primary outcome were preterm birth-risk score and vaginal fetal fibronection FDC-6 (logistic regression odds ratio [OR] 16.9 [95% confidence interval (CI) 3.1, 92.8]) and 8.0 ([95% CI 1.6, 38.2], respectively). Bacterial vaginosis, fetal fibronectin X18A4, fibronectin CAF, and cervical fetal fibronectin FDC-6 were not associated with spontaneous preterm birth; however, the statistical power to assess these variables was limited. The combination of positive preterm birth-risk score and vaginal fetal fibronectin FDC-6 had a sensitivity of 44.4%, specificity of 97.7%, positive predictive value of 57.1%, negative predictive value of 96.2%, and a significant likelihood ratio for a positive test of 19.4 (95% CI 5.1, 73.8). CONCLUSION: The combination of preterm birth-risk score and vaginal fetal fibronectin FDC-6 predicted spontaneous preterm birth. Intervention trials are required to determine whether a combination of screening tests will reduce rates of spontaneous preterm birth.

Adult↗
PubMed1999

Neonatal outcomes with placenta previa.

OBJECTIVE: To identify neonatal complications associated with placenta previa. METHODS: This was a population-based, retrospective cohort study involving all singleton deliveries in Nova Scotia from 1988 to 1995. The study group consisted of all completed singleton pregnancies complicated by placenta previa; all other singleton pregnancies were considered controls. Patient information was collected from the Nova Scotia Atlee perinatal database. Neonatal complications were evaluated while controlling for potential confounders. The data were analyzed using chi2, Fisher exact test, and multiple logistic regression. RESULTS: Among 92,983 pregnancies delivered during the study period, 305 cases of placenta previa were identified (0.33%). After controlling for potential confounders, neonatal complications significantly associated with placenta previa included major congenital anomalies (odds ratio [OR] 2.48), respiratory distress syndrome (OR 4.94), and anemia (OR 2.65). The perinatal mortality rate associated with placenta previa was 2.30% (compared with 0.78% in controls) and was explained by gestational age at delivery, occurrence of congenital anomalies, and maternal age. Although there was a higher rate of preterm births in the placenta previa group (46.56% versus 7.27%), there was no difference in birth weights between groups after controlling for gestational age at delivery. CONCLUSION: Neonatal complications of placenta previa included preterm birth, congenital anomalies, respiratory distress syndrome, and anemia. There was no increased occurrence of fetal growth restriction.

Cohort Studies↗
PubMed1999

Randomized comparison of oral misoprostol and oxytocin for labor induction in term prelabor membrane rupture.

OBJECTIVES: To compare labor induction intervals between oral misoprostol and intravenous oxytocin in women who present at term with premature rupture of membranes. METHODS: One hundred eight women were randomly assigned to misoprostol 50 microg orally every 4 hours as needed or intravenous oxytocin. The primary outcome measure was time from induction to vaginal delivery. Sample size was calculated using a two-tailed alpha of 0.05 and power of 80%. RESULTS: Baseline demographic data, including maternal age, gestation, parity, Bishop score, birth weight, and group B streptococcal status, were similar. The mean time +/-standard deviation to vaginal birth with oral misoprostol was 720+/-382 minutes compared with 501+/-389 minutes with oxytocin (P = .007). The durations of the first, second, and third stages of labor were similar. There were no differences in maternal secondary outcomes, including cesarean birth (eight and seven, respectively), infection, maternal satisfaction with labor, epidural use, perineal trauma, manual placental removal, or gastrointestinal side effects. Neonatal outcomes including cord pH, Apgar scores, infection, and admission to neonatal intensive care unit were not different. CONCLUSION: Although labor induction with oral misoprostol was effective, oxytocin resulted in a shorter induction-to-delivery interval. Active labor intervals and other maternal and neonatal outcomes were similar.

Female↗