Discrete and Effortful Imagined Movements Do Not Specifically Activate the Autonomic Nervous System

International audienceBACKGROUND: The autonomic nervous system (ANS) is activated in parallel with the motor system during cyclical and effortful imagined actions. However, it is not clear whether the ANS is activated during motor imagery of discrete movements and whether this activation is specific to the movement being imagined. Here, we explored these topics by studying the baroreflex control of the cardiovascular system. METHODOLOGY/PRINCIPAL FINDINGS: Arterial pressure and heart rate were recorded in ten subjects who executed or imagined trunk or leg movements against gravity. Trunk and leg movements result in different physiological reactions (orthostatic hypotension phenomenon) when they are executed. Interestingly, ANS activation significantly, but similarly, increased during imagined trunk and leg movements. Furthermore, we did not observe any physiological modulation during a control mental-arithmetic task or during motor imagery of effortless movements (horizontal wrist displacements). CONCLUSIONS/SIGNIFICANCE: We concluded that ANS activation during motor imagery is general and not specific and physiologically prepares the organism for the upcoming effortful action

Arginase activities and global arginine bioavailability in wild-type and ApoE-deficient mice: Responses to high fat and high cholesterol diets

Increased catabolism of arginine by arginase is increasingly viewed as an important pathophysiological factor in cardiovascular disease, including atherosclerosis induced by high cholesterol diets. Whereas previous studies have focused primarily on effects of high cholesterol diets on arginase expression and arginine metabolism in specific blood vessels, there is no information regarding the impact of lipid diets on arginase activity or arginine bioavailability at a systemic level. We, therefore, evaluated the effects of high fat (HF) and high fat-high cholesterol (HC) diets on arginase activity in plasma and tissues and on global arginine bioavailability (defined as the ratio of plasma arginine to ornithine + citrulline) in apoE-/- and wild-type C57BL/6J mice. HC and HF diets led to reduced global arginine bioavailability in both strains. The HC diet resulted in significantly elevated plasma arginase in both strains, but the HF diet increased plasma arginase only in apoE-/- mice. Elevated plasma arginase activity correlated closely with increased alanine aminotransferase levels, indicating that liver damage was primarily responsible for elevated plasma arginase. The HC diet, which promotes atherogenesis, also resulted in increased arginase activity and expression of the type II isozyme of arginase in multiple tissues of apoE-/- mice only. These results raise the possibility that systemic changes in arginase activity and global arginine bioavailability may be contributing factors in the initiation and/or progression of cardiovascular disease

Iron Behaving Badly: Inappropriate Iron Chelation as a Major Contributor to the Aetiology of Vascular and Other Progressive Inflammatory and Degenerative Diseases

The production of peroxide and superoxide is an inevitable consequence of aerobic metabolism, and while these particular "reactive oxygen species" (ROSs) can exhibit a number of biological effects, they are not of themselves excessively reactive and thus they are not especially damaging at physiological concentrations. However, their reactions with poorly liganded iron species can lead to the catalytic production of the very reactive and dangerous hydroxyl radical, which is exceptionally damaging, and a major cause of chronic inflammation. We review the considerable and wide-ranging evidence for the involvement of this combination of (su)peroxide and poorly liganded iron in a large number of physiological and indeed pathological processes and inflammatory disorders, especially those involving the progressive degradation of cellular and organismal performance. These diseases share a great many similarities and thus might be considered to have a common cause (i.e. iron-catalysed free radical and especially hydroxyl radical generation). The studies reviewed include those focused on a series of cardiovascular, metabolic and neurological diseases, where iron can be found at the sites of plaques and lesions, as well as studies showing the significance of iron to aging and longevity. The effective chelation of iron by natural or synthetic ligands is thus of major physiological (and potentially therapeutic) importance. As systems properties, we need to recognise that physiological observables have multiple molecular causes, and studying them in isolation leads to inconsistent patterns of apparent causality when it is the simultaneous combination of multiple factors that is responsible. This explains, for instance, the decidedly mixed effects of antioxidants that have been observed, etc...Comment: 159 pages, including 9 Figs and 2184 reference

Symposium Le développement professionnel pédagogique des enseignants du supérieur : questionner les postures des acteurs

International audienc

Nutritional status and the incidence of pneumonia in nursing home residents : results from the INCUR study

Objectives: To examine the predictive value of the Mini Nutritional Assessment-short form (MNA-SF) and its individual items on the incidence of pneumonia. Design: Prospective observational cohort study over 1-year of follow-up. Participants: A total of 773 older persons (74.4% women) living in 13 French nursing homes from the Incidence of pNeumonia and related ConseqUences in nursing home Residents (INCUR) study. Measurements: Nutritional status was assessed using the MNA-SF questionnaire at baseline. Diagnosis of pneumonia was based on clinical conditions retrieved from a medical chart. Cox proportional hazard models were applied to test whether the MNA-SF score and its single components predict pneumonia events over 1 year of follow-up. Results: After 1 year of follow-up, 160 (21%) incident cases of pneumonia were recorded. Mean age of participants was 86.2 (SD 7.5) years. Mean MNA-SF score was 9.8 (SD 2.4), with more than half of the participants (58.7%) being at risk of malnutrition (8-11 points). The total MNA-SF score and its categories did not predict the studied outcome. However, a single component of the MNA-SF score, specifically decreased mobility, was a significant risk factor for pneumonia (hazard ratio 2.289; 95% confidence interval 1.357-3.860; P= .002), independently of potential confounders. Conclusions: The total MNA-SF score did not predict the incidence of pneumonia. However, decreased mobility was a significant risk factor, implying that individual components of the MNA-SF should be more carefully explored to verify whether they might be used for detecting specific declines of the health status in nursing home residents, thus potentially improving the risk profile estimation of such a complex population

Frailty Index and Mortality in Nursing Home Residents in France : Results From the INCUR Study

The objective of this study was to examine whether the capacity of an age-related deficit accumulation index (the so-called Frailty Index [FI] proposed by Rockwood) to predict mortality in a nursing home population. Design, Setting, and Participants: Data are from a longitudinal cohort study (ie, the Incidence of pNeumonia and related ConseqUences in nursing home Residents [INCUR]) of 773 older persons (74.4% women) living in 13 French nursing homes. Measurements: The FI was computed as the ratio between actual and 30 potential deficits the participant might have presented at the baseline visit (range between 0 [no deficit] and 1 [30 deficits]). Death events were monitored and detected over a 12-month follow-up. The risk of death was estimated using Cox proportional hazards models. Results: Mean age of participants was 86.2 (SD 7.5) years, with a mean FI of 0.35 (SD 0.11). At the end of the follow-up, 135 (17.4%) death events were recorded. A positive association between the FI and mortality (per 0.01 FI increment: age- and gender-adjusted hazard ratio 1.018, 95% confidence interval 1.002-1.035, P =.03) was reported. The use of the traditional 0.25 cut-point for detecting the frailty status is inadequate in this population. Conclusion: The FI is able to predict mortality even in very old and complex elders, such as nursing home residents

Frailty Index and Quality of Life in Nursing Home Residents : Results From INCUR Study

Background. Frailty is a common clinical syndrome in older adults that carries an increased risk for poor health outcomes. The aim of this study was to examine the relationship between frailty and health-related Quality of Life (QoL) in older nursing home patients. Methods. The study sample consisted of 590 patients aged 65 years or older. QoL was measured with the Visual Analogue Scale. Frailty was assessed using the Frailty Index as proposed by Rockwood and colleagues. Results. Mean age of the participants was 85.9 (standard deviation [SD] 7.6) years, with 73.6% being female. The mean Frailty Index was 0.40 (SD 0.07) and the mean value of QoL was 67.4 out of 100 (SD 25.9). Before and after adjusting for age, and stratification for sociodemographic, and health-related variables, no significant associations between frailty and QoL were reported. Conclusion. In our study, the Frailty Index was not associated with QoL in nursing home residents

J Nat Prod

The inhibition of arginase is of substantial interest for the treatment of various diseases of public health interest including cardiovascular diseases. Using an ex vivo experiment on rat aortic rings and an in vitro assay with liver bovine purified arginase, it was demonstrated that several polyphenolic extracts from Cyperus and Carex species possess vasorelaxant properties and mammalian arginase inhibitory capacities. Phytochemical studies performed on these species led to the identification of eight compounds, including monomers, dimers, trimers, and tetramers of resveratrol. The potential of these stilbenes as inhibitors of mammalian arginase was assessed. Five compounds, scirpusin B (5), ε-viniferin (4), cyperusphenol B (6), carexinol A (7), and the new compound virgatanol (1), showed significant inhibition of arginase, with percentage inhibition ranging from 70% to 95% at 100 μg/mL and IC values between 12.2 and 182.1 μM, confirming that these stilbenes may be useful for the development of new pharmaceutical products