1,513 research outputs found
The Formation of the Double Pulsar PSR J0737-3039A/B
Recent timing observations of the double pulsar J0737-3039A/B have shown that
its transverse velocity is extremely low, only 10 km/s, and nearly in the Plane
of the Galaxy. With this new information, we rigorously re-examine the history
and formation of this system, determining estimates of the pre-supernova
companion mass, supernova kick and misalignment angle between the pre- and
post-supernova orbital planes. We find that the progenitor to the recently
formed `B' pulsar was probably less than 2 MSun, lending credence to
suggestions that this object may not have formed in a normal supernova
involving the collapse of an iron core. At the same time, the supernova kick
was likely non-zero. A comparison to the history of the double-neutron-star
binary B1534+12 suggests a range of possible parameters for the progenitors of
these systems, which should be taken into account in future binary population
syntheses and in predictions of the rate and spatial distribution of short
gamma-ray burst events.Comment: To appear in MNRAS Letters. Title typo fix only; no change to pape
Importance of adequate sample sizes in fatty acid intervention trials
Abstract not availableLisa N. Yelland, Maria Makrides, Andrew J. McPhee, Julie Quinlivan, Robert A. Gibso
Comparison of MRI and DXA to measure muscle size and age-related atrophy in thigh muscles.
OBJECTIVES
Magnetic resonance imaging (MRI) and dual-energy x-ray absorptiometry (DXA) were used to examine the thigh lean mass in young and old men and women.
METHODS
A whole-body DXA scan was used to estimate thigh lean mass in young (20 men; 22.4±3.1y; 18 women; 22.1±2.0y) and older adults (25 men; 72.3±4.9y; 28 women; 72.0±4.5y). Thigh lean mass determined with a thigh scan on the DXA or full thigh MRI scans were compared.
RESULTS
Although the thigh lean mass quantified by DXA and MRI in young and older participants were correlated (R(2)=0.88; p<0.001) the magnitude of the differences in thigh lean mass between young and old was smaller with DXA than MRI (old vs. young men 79.5±13.1% and 73.4±11.2%; old vs. young women 88.6±11.8% and 79.4±12.3%, respectively). Detailed analysis of MRI revealed 30% smaller quadriceps muscles in the older than young individuals, while the other thigh muscles were only 18% smaller.
CONCLUSIONS
DXA underestimates the age-related loss of thigh muscle mass in comparison to MRI. The quadriceps muscles were more susceptible to age-related atrophy compared with other thigh muscles
Effects of diabetes family history and exercise training on the expression of adiponectin and leptin and their receptors
The daughters of patients with diabetes have reduced insulin sensitivity index (ISI) scores compared with women with no family history of
diabetes, but their ISI increase more in response to exercise training(1). The present study aimed to determine whether differences between
these groups in exercise-induced changes in circulating adiponectin and leptin concentrations and expression of their genes and receptors
in subcutaneous adipose tissue (SAT), could explain differences in the exercise-induced changes in ISI between women with and without
a family history of diabetes
Vaginal progesterone pessaries for pregnant women with a previous preterm birth to prevent neonatal respiratory distress syndrome (the PROGRESS Study): A multicentre, randomised, placebo-controlled trial
Published: September 26, 2017Background: Neonatal respiratory distress syndrome, as a consequence of preterm birth, is a major cause of early mortality and morbidity. The withdrawal of progesterone, either actual or functional, is thought to be an antecedent to the onset of labour. There remains limited information on clinically relevant health outcomes as to whether vaginal progesterone may be of benefit for pregnant women with a history of a previous preterm birth, who are at high risk of a recurrence. Our primary aim was to assess whether the use of vaginal progesterone pessaries in women with a history of previous spontaneous preterm birth reduced the risk and severity of respiratory distress syndrome in their infants, with secondary aims of examining the effects on other neonatal morbidities and maternal health and assessing the adverse effects of treatment. Methods: Women with a live singleton or twin pregnancy between 18 to <24 weeks' gestation and a history of prior preterm birth at less than 37 weeks' gestation in the preceding pregnancy, where labour occurred spontaneously or in association with cervical incompetence or following preterm prelabour rupture of the membranes, were eligible. Women were recruited from 39 Australian, New Zealand, and Canadian maternity hospitals and assigned by randomisation to vaginal progesterone pessaries (equivalent to 100 mg vaginal progesterone) (n = 398) or placebo (n = 389). Participants and investigators were masked to the treatment allocation. The primary outcome was respiratory distress syndrome and severity. Secondary outcomes were other respiratory morbidities; other adverse neonatal outcomes; adverse outcomes for the woman, especially related to preterm birth; and side effects of progesterone treatment. Data were analysed for all the 787 women (100%) randomised and their 799 infants. Findings: Most women used their allocated study treatment (740 women, 94.0%), with median use similar for both study groups (51.0 days, interquartile range [IQR] 28.0-69.0, in the progesterone group versus 52.0 days, IQR 27.0-76.0, in the placebo group). The incidence of respiratory distress syndrome was similar in both study groups-10.5% (42/402) in the progesterone group and 10.6% (41/388) in the placebo group (adjusted relative risk [RR] 0.98, 95% confidence interval [CI] 0.64-1.49, p = 0.912)-as was the severity of any neonatal respiratory disease (adjusted treatment effect 1.02, 95% CI 0.69-1.53, p = 0.905). No differences were seen between study groups for other respiratory morbidities and adverse infant outcomes, including serious infant composite outcome (155/406 [38.2%] in the progesterone group and 152/393 [38.7%] in the placebo group, adjusted RR 0.98, 95% CI 0.82-1.17, p = 0.798). The proportion of infants born before 37 weeks' gestation was similar in both study groups (148/406 [36.5%] in the progesterone group and 146/393 [37.2%] in the placebo group, adjusted RR 0.97, 95% CI 0.81-1.17, p = 0.765). A similar proportion of women in both study groups had maternal morbidities, especially those related to preterm birth, or experienced side effects of treatment. In 9.9% (39/394) of the women in the progesterone group and 7.3% (28/382) of the women in the placebo group, treatment was stopped because of side effects (adjusted RR 1.35, 95% CI 0.85-2.15, p = 0.204). The main limitation of the study was that almost 9% of the women did not start the medication or forgot to use it 3 or more times a week. Conclusions: Our results do not support the use of vaginal progesterone pessaries in women with a history of a previous spontaneous preterm birth to reduce the risk of neonatal respiratory distress syndrome or other neonatal and maternal morbidities related to preterm birth. Individual participant data meta-analysis of the relevant trials may identify specific women for whom vaginal progesterone might be of benefit. Current Clinical Trials ISRCTN20269066.Caroline A. Crowther, Pat Ashwood, Andrew J. McPhee, Vicki Flenady, Thach Tran, Jodie M. Dodd, Jeffrey S. Robinson, for the PROGRESS Study Grou
Paternal obesity modifies the effect of an antenatal lifestyle intervention in women who are overweight or obese on newborn anthropometry
The contribution of paternal obesity to pregnancy outcomes has been little described. Our aims were to determine whether the effect of an antenatal maternal dietary and lifestyle intervention among women who are overweight or obese on newborn adiposity, was modified by paternal obesity. We conducted a secondary analysis of a multicenter randomised trial. Pregnant women with BMI ≥25 kg/m2 received either Lifestyle Advice or Standard Care. Paternal anthropometric measures included height, weight, BMI; waist, hip, calf and mid-upper arm circumferences; biceps and calf skinfold thickness measurements (SFTM); and percentage body fat. Newborn anthropometric outcomes included length; weight; head, arm, abdominal, and chest circumferences; biceps, triceps, subscapular, suprailiac, thigh, and lateral abdominal wall SFTM; and percentage body fat. The effect of an antenatal maternal dietary and lifestyle intervention among women who were overweight or obese on neonatal anthropometric measures, was significantly modified by paternal BMI ≥35.0 kg/m2, with a significantly smaller infant triceps, suprailiac, and thigh SFTM, and percent fat mass, compared with that observed in offspring of lean fathers. Further research is required to determine whether our observed associations are causal, and whether paternal weight loss prior to conception is a potential strategy to reduce the intergenerational effects of obesity.Jodie M. Dodd, Lodewyk E. Du Plessis, Andrea R. Deussen, Rosalie M. Grivell, Lisa N. Yelland, Jennie Louise, Andrew J. Mcphee, Jeffrey S. Robinson and Julie A. Owen
The intention to hasten death: a survey of attitudes and practices of surgeons in Australia
Objective: To determine attitudes among surgeons in Australia to assisted death, and the proportion of surgeons who have intentionally hastened death with or without an explicit request. Design: Anonymous, cross-sectional, mail-out survey between August and November 1999. Participants: 683 out of 992 eligible general surgeons (68.9% response rate). Main outcome measures: Proportion of respondents answering affirmatively to questions about administering excessive doses of medication with an intention to hasten death. Results: 247 respondents (36.2%; 95% CI, 32.6%-39.9%) reported that, for the purpose of relieving a patient's suffering, they have given drugs in doses that they perceived to be greater than those required to relieve symptoms with the intention of hastening death. More than half of these (139 respondents; 20.4% of all respondents; 95% CI, 17.4%-23.6%) reported that they had never received an unambiguous request for a lethal dose of medication. Of all respondents, only 36 (5.3%; 95% CI, 2.9%-6.1%) reported that they had given a bolus lethal injection, or had provided the means to commit suicide, in response to an unambiguous request. Conclusions: More than a third of surgeons surveyed reported giving drugs with an intention to hasten death, often in the absence of an explicit request. However, in many instances, this may involve the use of an infusion of analgesics or sedatives, and such actions may be difficult to distinguish from accepted palliative care, except on the basis of the doctor's self-reported intention. Legal and moral distinctions based solely on a doctor's intention are problematic
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