5,974 research outputs found
Are There Clinical Cardiac Complications From Too Much Exercise?
The dose-response association between physical activity and cardiovascular outcomes is well described (10). As little as 15 min·d−1 of moderate-intensity exercise significantly lowers the risk for cardiovascular morbidity and mortality. Greater volumes yield greater cardiovascular benefit. However, the impact of extreme volumes of exercise on cardiovascular health is under debate (9), because some studies present evidence of adverse clinical outcomes in endurance athletes who perform exercise volumes at the extreme upper end of the physical activity continuum. These observations raise the possibility that high doses of exercise have deleterious cardiac effects
Limb amputations in fixed dystonia: a form of body integrity identity disorder?
Fixed dystonia is a disabling disorder mainly affecting young women who develop fixed abnormal limb postures and pain after apparently minor peripheral injury. There is continued debate regarding its pathophysiology and management. We report 5 cases of fixed dystonia in patients who sought amputation of the affected limb. We place these cases in the context of previous reports of patients with healthy limbs and patients with chronic regional pain syndrome who have sought amputation. Our cases, combined with recent data regarding disorders of mental rotation in patients with fixed dystonia, as well as previous data regarding body integrity identity disorder and amputations sought by patients with chronic regional pain syndrome, raise the possibility that patients with fixed dystonia might have a deficit in body schema that predisposes them to developing fixed dystonia and drives some to seek amputation. The outcome of amputation in fixed dystonia is invariably unfavorable
Special Article: Physical Activity, Physical Fitness, and Cardiovascular Risk Factors in Childhood
In adults, physical activity and exercise training are associated with reduced cardiovascular morbidity and mortality, a reduced likelihood of developing adverse cardiovascular risk factors, and improved insulin sensitivity. In childhood, participation in appropriate physical activity may prevent the development of cardiovascular risk factors in the future and complement treatment of existing cardiovascular risk factors, including hypertension, dyslipidemia, and overweight. Exercise in children can also significantly improve insulin sensitivity independent of weight loss. These e fects are mediated in overweight children by increases in lean body mass relative to fat mass and associated improvements in inflammatory mediators, endothelial function, and the associated adverse hormonal milieu
Exercise and Coronary Atherosclerosis: Observations, Explanations, Relevance, and Clinical Management.
Physical activity and exercise training are effective strategies for reducing the risk of cardiovascular events, but multiple studies have reported an increased prevalence of coronary atherosclerosis, usually measured as coronary artery calcification, among athletes who are middle-aged and older. Our review of the medical literature demonstrates that the prevalence of coronary artery calcification and atherosclerotic plaques, which are strong predictors for future cardiovascular morbidity and mortality, was higher in athletes compared with controls, and was higher in the most active athletes compared with less active athletes. However, analysis of plaque morphology revealed fewer mixed plaques and more often only calcified plaques among athletes, suggesting a more benign composition of atherosclerotic plaques. This review describes the effects of physical activity and exercise training on coronary atherosclerosis in athletes who are middle-aged and older and aims to contribute to the understanding of the potential adverse effects of the highest doses of exercise training on the coronary arteries. For this purpose, we will review the association between exercise and coronary atherosclerosis measured using computed tomography, discuss the potential underlying mechanisms for exercise-induced coronary atherosclerosis, determine the clinical relevance of coronary atherosclerosis in middle-aged athletes and describe strategies for the clinical management of athletes with coronary atherosclerosis to guide physicians in clinical decision making and treatment of athletes with elevated coronary artery calcification scores
Exploring the utility of Acxiom’s Research Opinion Poll data for use in social science research
Acxiom’s Research Opinion Poll (ROP), a voluntary survey designed to capture detailed information about household consumption and expenditure across Great Britain, has the potential to provide information valuable for social science research. This paper provides a review of the ROP, indicating that the survey in undertaken through a number of channels which enable Acxiom to generate over one million household responses a year. The ROP micro data collected are used in the construction of many of Acxiom’s aggregate products including its geo-demographic classification system called ‘PersonicX’. The ROP is found to compare favourably in areas such as sample size, geographic detail, consistency and data quality and accuracy when compared against government datasets including the 2001 Census, the Living Costs and Food Survey, the Labour Force Survey, the British Household Panel Survey, the General Lifestyle Survey and the English Housing Survey
Two cases of food aversion with semantic dementia
Accounts of altered eating behavior in semantic dementia generally emphasize gluttony and abnormal food preferences. Here we describe two female patients with no past history of eating disorders who developed early prominent aversion to food in the context of an otherwise typical semantic dementia syndrome. One patient (aged 57) presented features in line with anorexia nervosa while the second patient (aged 58) presented with a syndrome more suggestive of bulimia nervosa. These cases add to the growing spectrum of apparently dichotomous behavior patterns in the frontotemporal dementias and illustrate a potentially under-recognized cause of eating disorders presenting in later life
The effect of interferon beta-1b treatment on MRI measures of cerebral atrophy in secondary progressive multiple sclerosis.
The recently completed European trial of interferon beta-1b (IFN beta -1b) in patients with secondary progressive multiple sclerosis (SP multiple sclerosis) has given an opportunity to assess the impact of treatment on cerebral atrophy using serial MRI. Unenhanced T-1-weighted brain imaging was acquired in a subgroup of 95 patients from five of the European centres; imaging was performed at 6-month intervals from month 0 to month 36. A blinded observer measured cerebral volume on four contiguous 5 mm cerebral hemisphere slices at each time point, using an algorithm with a high level of reproducibility and automation. There was a significant and progressive reduction in cerebral volume in both placebo and treated groups, with a mean reduction of 3.9 and 2.9%, respectively, by month 36 (P = 0.34 between groups). Exploratory subgroup analyses indicated that patients without gadolinium (Gd) enhancement at the baseline had a greater reduction of cerebral volume in the placebo group (mean reduction at month 36: placebo 5.1%, IFN beta -1b 1.8%, P < 0.05) whereas those with Gd-enhancing lesions showed a trend to greater reduction of cerebral volume if the patient was on IFN<beta>-1b (placebo 2.6%, IFN beta -1b, 3.7%; P > 0.05). These results are consistent with ongoing tissue loss in both arms of this study of secondary progressive multiple sclerosis. This finding is concordant with previous observations that disease progression, although delayed, is not halted by IFN beta. The different pattern seen in patients with and without baseline gadolinium enhancement suggests that part of the cerebral volume reduction observed in IFN beta -treated patients may be due to the anti-inflammatory/antioedematous effect of the drug. Longer periods of observation and larger groups of patients may be needed to detect the effects of treatment on cerebral atrophy in this population of patients with advanced disease
Structure and Transport in Coatings from Multiscale Computed Tomography of Coatings-New Perspectives for Eelectrochemical Impedance Spectroscopy Modeling?
Computed Tomography (CT) is an approach that has been extensively applied in many areas of science from understanding structures in living organisms to materials science. In materials science, the study of structures within coatings presents challenges on at least two different levels. First, the structure of the coatings needs to be understood from the atomic scale, where dissolution reactions begin, up to length scales which cover the aggregation of inhibitors and other additives, which take place at ∼10−5 m, i.e. 4 to 5 orders of magnitude. CT is a favourable imaging technique since it allows multiscale information to be obtained non-destructively down to tens of nanometres. In this study X-ray absorption contrast imaging has been used to examine structures created using strontium chromate (SrCrO4) particles embedded in an epoxy film. It has been found that SrCrO4 particles can form clusters that extend a few hundred microns in the plane of the film, span the thickness of the film and have fractal characteristics. There are also volumes of low density epoxy of similar sizes and characteristics to the SrCrO4 clusters. The SrCrO4 clusters have a strong influence on the leaching behaviour since the release changes with time. Initially, leaching is controlled by direct dissolution but, as the clusters dissolve, the release is dominated by the fractal dimension of the cluster. The dissolved clusters leave behind voids filled with electrolyte that provide alternative transport pathways for corrosive ions through the polymer. In this paper, the nature of these clusters will be reviewed and the implication for transport properties and electrochemical assessment will be explored
The Relationship Between Lifelong Exercise Volume and Coronary Atherosclerosis in Athletes.
Background -Higher levels of physical activity are associated with a lower risk of cardiovascular events. Nevertheless, there is debate on the dose-response relationship of exercise and CVD outcomes and whether high volumes of exercise may accelerate coronary atherosclerosis. We aimed to determine the relationship between lifelong exercise volumes and coronary atherosclerosis. Methods -Middle aged men engaged in competitive or recreational leisure sports underwent a non-contrast and contrast-enhanced computed tomography scan to assess coronary artery calcification (CAC) and plaque characteristics. Participants reported lifelong exercise history patterns. Exercise volumes were multiplied by Metabolic Equivalent of Task (MET) scores to calculate MET-min/week. Participants were categorized as 2000 MET-min/week. Results -284 men (55±7 years) were included. CAC was present in 150/284 (53%) participants with a median CAC score of 35.8 [9.3-145.8). Athletes with a lifelong exercise volume >2000 MET-min/week (n=75) had a significantly higher CAC score (9.4 [0-60.9] versus 0 [0-43.5], p=.02) and prevalence of CAC (68%,ORadjusted=3.2 (95%CI: 1.6-6.6)) and plaque (77%, ORadjusted=3.3 (95%CI: 1.6-7.1)) compared to 0, there was no difference in CAC score (p=.20), area (p=.21), density (p=.25) and regions of interest (p=.20) across exercise volume groups. Among participants with plaque, the most active group (>2000 MET-min/week) had a lower prevalence of mixed plaques (48% versus 69%, ORadjusted=0.35 (95%CI: 0.15-0.85) and more often had only calcified plaques (38% versus 16%, ORadjusted=3.57 (95%CI: 1.28-9.97)) compared to the least active group (2000 MET-min/week group had a higher prevalence of CAC and atherosclerotic plaques. The most active group did however have a more benign composition of plaques, with fewer mixed plaques and more often only calcified plaques. These observations may explain the increased longevity typical of endurance athletes despite the presence of more coronary atherosclerotic plaque in the most active participants
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