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Biomedical subjects

A McEwen

Publications and source records attributed to A McEwen.

At least 19 recordsLinked to original sources
PubMed2006

Cassini observes the active south pole of Enceladus.

Cassini has identified a geologically active province at the south pole of Saturn's moon Enceladus. In images acquired by the Imaging Science Subsystem (ISS), this region is circumscribed by a chain of folded ridges and troughs at approximately 55 degrees S latitude. The terrain southward of this boundary is distinguished by its albedo and color contrasts, elevated temperatures, extreme geologic youth, and narrow tectonic rifts that exhibit coarse-grained ice and coincide with the hottest temperatures measured in the region. Jets of fine icy particles that supply Saturn's E ring emanate from this province, carried aloft by water vapor probably venting from subsurface reservoirs of liquid water. The shape of Enceladus suggests a possible intense heating epoch in the past by capture into a 1:4 secondary spin/orbit resonance.

Extraterrestrial Environment↗
PubMed2005

Cassini Imaging Science: initial results on Saturn's atmosphere.

The Cassini Imaging Science Subsystem (ISS) began observing Saturn in early February 2004. From analysis of cloud motions through early October 2004, we report vertical wind shear in Saturn's equatorial jet and a maximum wind speed of approximately 375 meters per second, a value that differs from both Hubble Space Telescope and Voyager values. We also report a particularly active narrow southern mid-latitude region in which dark ovals are observed both to merge with each other and to arise from the eruptions of large, bright storms. Bright storm eruptions are correlated with Saturn's electrostatic discharges, which are thought to originate from lightning.

Atmosphere↗
PubMed2005

Cassini Imaging Science: initial results on Phoebe and Iapetus.

The Cassini Imaging Science Subsystem acquired high-resolution imaging data on the outer Saturnian moon, Phoebe, during Cassini's close flyby on 11 June 2004 and on Iapetus during a flyby on 31 December 2004. Phoebe has a heavily cratered and ancient surface, shows evidence of ice near the surface, has distinct layering of different materials, and has a mean density that is indicative of an ice-rock mixture. Iapetus's dark leading side (Cassini Regio) is ancient, heavily cratered terrain bisected by an equatorial ridge system that reaches 20 kilometers relief. Local albedo variations within and bordering Cassini Regio suggest mass wasting of ballistically deposited material, the origin of which remains unknown.

Extraterrestrial Environment↗
PubMed2005

Cassini Imaging Science: initial results on Saturn's rings and small satellites.

Images acquired of Saturn's rings and small moons by the Cassini Imaging Science Subsystem (ISS) during the first 9 months of Cassini operations at Saturn have produced many new findings. These include new saturnian moons; refined orbits of new and previously known moons; narrow diffuse rings in the F-ring region and embedded in gaps within the main rings; exceptionally fine-scale ring structure in moderate- to high-optical depth regions; new estimates for the masses of ring-region moons, as well as ring particle properties in the Cassini division, derived from the analysis of linear density waves; ring particle albedos in select ring regions; and never-before-seen phenomena within the rings.

Journal Article↗
PubMed2005

General practitioners' views on and referral to NHS smoking cessation services.

OBJECTIVES: Increasing the rate of smoking cessation remains a major public health goal. To help achieve this in the UK, National Health Service (NHS) smoking cessation services have been established to provide treatment for smokers wanting help with stopping. Referrals from general practitioners (GPs) are crucial to the success of these clinics. This study aimed to assess English GPs' self-reported interactions with, and attitudes towards, their local smoking cessation services. STUDY DESIGN: Postal survey assessing the attitudes of GPs in England towards, and formal interactions with, NHS smoking cessation services. METHODS: A questionnaire was posted to a random sample of 544 GPs in England (response rate 63%). GPs' self-reported interactions with smoking cessation services and their attitudes towards these clinics were assessed. GPs were also asked what factors determined whether they prescribed nicotine-replacement therapy (NRT) and Buproprion (Zyban), and what was the extent and nature of their smoking cessation interventions with their patients. RESULTS: Most GPs (94%) reported that they were aware of the specialist smoking cessation service in their area. Seventy percent of GPs supported the continuation of current funding for specialist smoking cessation services. Seventy percent reported that they referred patients to these services, and 55% had staff within their practices trained as community smoking cessation advisors. Most GPs (79%) reported 'clinical need' as a determinant of whether they prescribed NRT/Zyban, and a few GPs cited 'budgetary constraints' as a factor (15%). Ninety-eight percent of GPs reported that they record smoking status when new patients join their practice, and they advise smokers to stop 'at least every now and then'. CONCLUSIONS: GPs support the existence and continuation of specialist smoking cessation services, and most reported that they refer patients to them. Virtually every GP reported that they record smoking status when new patients join their practice, and they advise smokers to stop 'at least every now and then'.

Adult↗
PubMed2003

Induction of contact-dependent endothelial apoptosis by osteosarcoma cells suggests a role for endothelial cell apoptosis in blood-borne metastasis.

Although tumour cells are believed to migrate between endothelial cells early in metastasis, the possibility remains that endothelial apoptosis may also contribute to the tumour's breach of the vascular barrier. Although seemingly inconsistent with tumour angiogenesis, one publication describes the induction of contact-dependent apoptosis in cultured endothelium by tumour cells. The cell culture data are, however, open to challenge on technical grounds while there are no confirmatory reports. The present paper describes experiments overcoming these limitations. SAOS-2 human osteosarcoma cells and two rat carcinoma cell lines were co-cultured with human umbilical vein endothelial cells (HUVECs) and cultures labelled by surface lectin histochemistry for endothelium. The HUVEC culture density was determined and SAOS-2 cells, but not rat carcinoma cells, were found significantly to reduce HUVEC survival despite the release of potent growth factors as determined in separate experiments with tumour cell conditioned medium. Lectin labelling combined with light microscopy, transmission electron microscopy, flow cytometry for both lectin binding and DNA content, and DNA gel electrophoresis of SAOS-2/HUVEC co-cultures revealed extensive HUVEC apoptosis. These findings indicate contact-dependent endothelial apoptosis by SAOS-2, while this activity appeared weaker and overwhelmed by HUVEC proliferation with rat carcinoma cells. Importantly, this study supports the suggestion that endothelial apoptosis may be important for metastasis and suggests a complex interplay between endothelial proliferation and apoptosis in tumours.

Animals↗
PubMed2003

Increase in common cold symptoms and mouth ulcers following smoking cessation.

OBJECTIVE: To examine changes in reports of common cold symptoms and mouth ulcers following smoking cessation. It was hypothesised that reports of these symptoms would increase on stopping smoking. DESIGN: Smokers were assessed one week before stopping smoking (baseline), then after one, two, and six weeks of smoking abstinence. PARTICIPANTS: 174 smokers attending a seven week smoking cessation programme combining behavioural support with nicotine patches. MAIN OUTCOME MEASURES: Self reports of cold symptoms, mouth ulcers, and smoking abstinence (validated using expired carbon monoxide) were recorded on each measurement occasion. RESULTS: Following one, two, and six weeks of smoking abstinence 73.0% (127/174), 57.5% (100/174), and 44.8% (78/174) of the participants, respectively, maintained continuous abstinence and provided reports of cold symptoms and mouth ulcers. For those abstinent from smoking for six weeks, relative to baseline, a significant increase in reports of the number of cold symptoms was observed following one and two weeks of smoking abstinence (p = 0.009 and p = 0.038, respectively) and an increase in reports of mouth ulcers after one and two weeks of abstinence (p = 0.004 and p = 0.008, respectively). Following one week of abstinence significant increases in reports of sore throat, coughing, deafness, and sneezing were observed (p = 0.049, p < 0.001, p< 0.039, and p < 0.003, respectively). CONCLUSIONS: This is the first study to systematically document significant increases in cold symptoms and mouth ulcers following smoking cessation. Smokers should be informed that they have an increased chance of experiencing these symptoms on stopping smoking. Being psychologically prepared for these effects may reduce their impact on the attempt to stop smoking.

Adult↗
PubMed2001

General Practitioners' views on the provision of nicotine replacement therapy and bupropion.

BACKGROUND: Nicotine replacement therapies (NRT) and a new drug, bupropion, are licensed in several countries as aids to smoking cessation. General practitioners (GPs) play a crucial role in recommending or prescribing these medications. In the UK there has been discussion about whether the medications should be reimbursable by the National Health Service (NHS). This study assessed English GPs' attitudes towards reimbursement of NRT and bupropion. METHODS: Postal survey of a randomly selected national sample of GPs; 376 GPs completed the questionnaire after one reminder; effective response rate: 53%. There was no difference between the responses of GPs who responded to the initial request and those who responded only after a reminder suggesting minimal bias due to non-response. RESULTS: Attitudes of GPs were remarkably divided on most issues relating to the medications. Forty-three percent thought that bupropion should not be on NHS prescription while 42% thought that it should be (15% did not know); Fifty percent thought that NRT should not be on NHS prescription while 42% thought it should be (8% did not know). Requiring that smokers attend behavioural support programmes to be eligible to receive the medications on NHS prescription made no appreciable difference to the GPs' views. GPs were similarly divided on whether having the medications reimbursable would add unacceptably to their workload or offer a welcome opportunity to discuss smoking with their patients. A principal components analysis of responses to the individual questions on NRT and bupropion revealed that GPs' attitudes could be understood in terms of a single 'pro-con' dimension accounting for 53% of the total variance which made no distinction between the two medications. CONCLUSIONS: GPs in England appear to be divided in their attitudes to medications to aid smoking cessation and appear not to discriminate in their views between different types of medication or different aspects of their use. This suggests that their attitudes are generated by quite fundamental values. Addressing these values may be important in encouraging GPs to adhere more closely to national and international guidelines.

Antidepressive Agents, Second-Generation↗
PubMed2001

Smoking cessation and smoking patterns in the general population: a 1-year follow-up.

OBJECTIVE: To assess the prevalence of motivation and behaviours relating to smoking cessation and attempts at harm minimization and the stability of these over a 1-year period; to identify demographic, social, behavioural and psychological predictors of attempts to stop smoking and the success of these attempts. DESIGN: Face-to-face interviews were carried out with a national sample of UK smokers in April/May 1996 with follow-up 1 year later. SUBJECTS: The original response rate was 61% (1478 of 1911 adult smokers), and of these 1012 were followed-up 1 year later (68% of those who were originally contactable). RESULTS: Thirty-one per cent of smokers reported making at least one quit attempt during the follow-up period and 17% made a quit attempt in the first 9 months of that period. Of these 29% were still not smoking at least 3 months later. Fifty-one per cent of smokers had tried to cut down in the year leading up to the first survey. There was a fair degree of consistency over time in individual smokers' desires and intentions to stop smoking across both surveys and in the incidence of quit attempts and attempts to cut down. Beliefs about the effects of smoking on future health and having a partner who disliked their smoking were positively associated with making a quit attempt at follow-up while reporting enjoying smoking at baseline was negatively associated with making a quit attempt at follow-up. Time to first cigarette of the day and age of starting smoking were positively associated with success of quit attempts. CONCLUSIONS: Motivation and behaviours relating to smoking cessation are prevalent and fairly stable over time. Different factors appear to be related to attempts to stop and the success of those attempts. Interventions to increase smoking cessation in the population should take account of this.

Adult↗
PubMed2001

General Practitioners' views on the English national smoking cessation guidelines.

OBJECTIVES: Several countries have followed the US example in publishing national guidelines on smoking cessation interventions. Gauging responses to these guidelines can provide important lessons for future implementation and revision internationally. This study sought to assess General Practitioners' (GPs') views on recently published English smoking cessation guidelines that form the foundation of the UK National Health Service's smoking cessation strategy. DESIGN: Postal survey in which GPs were asked to judge the appropriateness, effectiveness and practicability of key recommendations for primary care in recent national smoking cessation guidelines. SETTING: General practice, England and Wales. SUBJECTS: Random national sample of GPs; 236 GPs completed the questionnaire; effective response rate: 62%. RESULTS: Only 16% of GPs accepted that all the recommendations in the guidelines were appropriate; 43% accepted that it was appropriate to check the smoking status of known smokers when they visit the surgery and only 30% thought it was practicable to advise smokers to stop at every opportunity. However, 77% of GPs thought that they should provide assistance for smokers wanting to stop; 74% believed that they should refer smokers to specialist services if appropriate and a similar proportion (77%) believed that it was appropriate to recommend nicotine replacement therapy. CONCLUSIONS: There was greater acceptance by GPs that they should assist smokers wanting to stop than that they should routinely monitor smoking status and give opportunistic advice to patients to stop. Given that opportunistic advice is a cornerstone of the national guidelines there is a need to find ways of reconciling what is being recommended and what GPs feel is appropriate.

Attitude of Health Personnel↗
PubMed2001

Smoking cessation activities by general practitioners and practice nurses.

OBJECTIVES: To assess general practitioners' and practice nurses' self reported behaviour, attitudes, and knowledge in relation to smoking cessation. DESIGN AND SETTING: Two postal surveys of random national samples of 303 GPs (survey 1) and 459 practice nurses (survey 2) covering England and Wales; effective response rates were 75% and 96%, respectively. RESULTS: Survey 1 found that 96% of GPs accepted that intervening against smoking was part of their role and almost all (99%) said that they recorded smoking status when patients registered; 57% reported that they routinely updated their records on smoking status, 50% said they advised smokers to stop during most or all consultations, and 76% said they advised smokers to cut down if they cannot stop. A large majority (83%) said they either recommended or prescribed nicotine replacement therapy (NRT). Although most GPs (86%) thought that NRTs were effective, only a minority thought they were worth the cost (47%) or should be on National Health Service (NHS) prescription (32%). There was little evidence that previous training in smoking cessation was associated with more activity, more positive attitudes, or greater knowledge. Survey 2 found that almost all practice nurses (99%) agreed that intervening against smoking was part of their role and 95% said they advised patients to stop at least occasionally; 71% said they advised smokers to stop at most or all consultations. A majority (74%) said that they recommended NRT to their patients. As with the GPs most practice nurses thought that nicotine replacement was effective (79%), but fewer (42%) thought the cost was justified, and only about half (53%) thought it should be available on NHS prescription. Nurses who said they had been trained in smoking cessation engaged in more activity relating to smoking cessation, had more positive attitudes, and were more knowledgeable. CONCLUSION: GPs and practice nurses accepted that intervening with smoking was an important part of their role and a large majority reported that they intervened at least with some smokers. This represents a promising baseline from which to proceed in terms of implementation of the new smoking cessation guidelines, but it is hoped that improvements can be made in terms of the frequency of updating records and intervening, and acceptance of the cost-effectiveness of NRT as a life preserving intervention.

Adult↗
PubMed2001

The national health demonstration projects.

The White Paper Towards a Healthier Scotland pledged 15 million Pounds to support four national health demonstration projects to lead the way in achieving sustained improvement in child health, young people's sexual health, coronary heart disease and cancer. The Starting Well project aims to demonstrate that child health in Glasgow can be improved by a programme of activities which both supports families and provides them with access to enhanced community-based resources. The Healthy Respect project aims to help young people in Lothian develop a positive attitude to their own sexuality and that of others, and a healthy respect for their partners, in order to reduce unplanned teenage pregnancies and sexually transmitted infections. The Have a Heart Paisley project is targeting coronary heart disease among the population of Scotland's largest town. The Cancer Challenge project is piloting a screening programme in the North East of Scotland for the detection of colorectal cancer. Though each project has specific objectives, appropriate to its own topic, all share underlying principles. The projects will act as test beds for action and a learning resource for the rest of Scotland.

Cardiovascular Diseases↗
PubMed2000

Prometheus: Io's wandering plume.

Unlike any volcanic behavior ever observed on Earth, the plume from Prometheus on Io has wandered 75 to 95 kilometers west over the last 20 years since it was first discovered by Voyager and more recently observed by Galileo. Despite the source motion, the geometric and optical properties of the plume have remained constant. We propose that this can be explained by vaporization of a sulfur dioxide and/or sulfur "snowfield" over which a lava flow is moving. Eruption of a boundary-layer slurry through a rootless conduit with sonic conditions at the intake of the melted snow can account for the constancy of plume properties.

Cold Temperature↗
PubMed2000

Exercise interventions for smoking cessation.

BACKGROUND: Taking exercise may help people give up smoking by moderating the effects of nicotine withdrawal. OBJECTIVES: To determine whether exercise-based interventions combined with a smoking cessation programme are more effective than a smoking cessation intervention alone. SEARCH STRATEGY: We searched The Cochrane Tobacco Addiction group specialised register for studies including the terms 'exercise' or 'physical activity' in February 2000. SELECTION CRITERIA: We included randomised trials comparing an exercise programme as an adjunct to a cessation programme with a cessation programme alone, recruiting smokers or recent quitters, and with a follow-up of 6 months or more. DATA COLLECTION AND ANALYSIS: We extracted data on study characteristics and smoking outcomes. Because of differences in studies we summarised the results narratively, making no attempt at meta-analysis. MAIN RESULTS: We identified eight trials, six of which had fewer than 25 people in each treatment arm. They varied in the timing and intensity of the smoking cessation and exercise programmes. Only one trial showed a significant benefit from the exercise programme at long term follow-up. REVIEWER'S CONCLUSIONS: Only one of the eight trials offered evidence for exercise aiding smoking cessation but the other trials were too small to exclude reliably an effect of intervention. Trials are needed with larger sample sizes, equal contact control conditions, tailored and lifestyle exercise programmes and measures of exercise adherence.

Exercise↗
PubMed2000

Does exercise aid smoking cessation? A systematic review.

AIMS: To assess the effectiveness of exercise-based interventions in smoking cessation. DESIGN: A systematic review was conducted of articles published between 1980 and 1999. The review focused on randomized controlled trials (RCTs) in which the specific effects of exercise on smoking abstinence were examined. The primary dependent variable was smoking abstinence. Other studies which had both exercise programming as an independent variable and smoking behaviour as a dependent variable are briefly discussed. PARTICIPANTS: The review included interventions targeting both healthy individuals and those with specific medical conditions. SETTINGS: The interventions were delivered in both community and inpatient settings. MEASUREMENTS: Information extracted from each article included details of the participants, exercise and smoking cessation programmes, control conditions, exercise adherence rates, length of follow-up and outcomes. FINDINGS: Of the eight trials satisfying our inclusion criteria, only two trials found a positive effect for exercise on smoking abstinence. The others showed no effect. CONCLUSIONS: There is some evidence for exercise aiding smoking cessation. Of the two trials finding a positive effect one was rigorously designed, the other was found to have numerous methodological limitations. Trials showing no effect lacked sensitivity. This was principally because of small sample sizes and inadequate measurement and control of exercise adherence. There is a need for more rigorously designed studies in this area.

Exercise↗
PubMed1998

Evidence for non-synchronous rotation of Europa. Galileo Imaging Team.

Non-synchronous rotation of Europa was predicted on theoretical grounds, by considering the orbitally averaged torque exerted by Jupiter on the satellite's tidal bulges. If Europa's orbit were circular, or the satellite were comprised of a frictionless fluid without tidal dissipation, this torque would average to zero. However, Europa has a small forced eccentricity e approximately 0.01 , generated by its dynamical interaction with Io and Ganymede, which should cause the equilibrium spin rate of the satellite to be slightly faster than synchronous. Recent gravity data suggest that there may be a permanent asymmetry in Europa's interior mass distribution which is large enough to offset the tidal torque; hence, if non-synchronous rotation is observed, the surface is probably decoupled from the interior by a subsurface layer of liquid or ductile ice. Non-synchronous rotation was invoked to explain Europa's global system of lineaments and an equatorial region of rifting seen in Voyager images. Here we report an analysis of the orientation and distribution of these surface features, based on initial observations made by the Galileo spacecraft. We find evidence that Europa spins faster than the synchronous rate (or did so in the past), consistent with the possibility of a global subsurface ocean.

Jupiter↗
PubMed1998

Use of a focussed teen prenatal clinic at a military teaching hospital: model for improved outcomes of unmarried mothers.

We evaluated the utility of a focussed, multidisciplinary adolescent clinic in improving perinatal outcomes. The study population included all delivering unmarried teenagers (13-19 years) from January 1, 1993 to December 31, 1995 attending the focussed adolescent obstetrical clinic compared to a similar cohort of married teenagers (13-19 years), married 20-24 year-old patients, and unmarried 20-24 year-old patients. There were no statistical differences in chorioamnionitis, intrauterine growth retardation (IUGR), postpartum haemorrhage, maternal weight gain, mean gestational age at delivery, preterm delivery rates (<37 weeks), low birth-weight (<2,500 g), Caesarean delivery, postterm delivery rates (>41 weeks), macrosomia (>4,000 g), placental abruption, chronic hypertension, alcohol use, Apgar scores or stillbirth rates or neonatal death rates among the 4 groups studied. Statistical differences were noted in mean delivery weights (p<0.05), preeclampsia (p<0.004), gestational diabetes (p<0.01), history of substance abuse (p<0.0001), tobacco use (p<0.0001), and forceps delivery rates (p<0.004). However, in the teen cohort none of these differences appeared to adversely affect perinatal outcomes in our patients. The focussed, adolescent obstetrical clinic appears to provide perinatal morbidities equal to a low-risk, general population generating better than expected outcomes for pregnant teenagers.

Adolescent↗