Chronic exercise preserves lean muscle mass in masters athletes.

Aging is commonly associated with a loss of muscle mass and strength, resulting in falls, functional decline, and the subjective feeling of weakness. Exercise modulates the morbidities of muscle aging. Most studies, however, have examined muscle-loss changes in sedentary aging adults. This leaves the question of whether the changes that are commonly associated with muscle aging reflect the true physiology of muscle aging or whether they reflect disuse atrophy. This study evaluated whether high levels of chronic exercise prevents the loss of lean muscle mass and strength experienced in sedentary aging adults. A cross-section of 40 high-level recreational athletes ("masters athletes") who were aged 40 to 81 years and trained 4 to 5 times per week underwent tests of health/activity, body composition, quadriceps peak torque (PT), and magnetic resonance imaging of bilateral quadriceps. Mid-thigh muscle area, quadriceps area (QA), subcutaneous adipose tissue, and intramuscular adipose tissue were quantified in magnetic resonance imaging using medical image processing, analysis, and visualization software. One-way analysis of variance was used to examine age group differences. Relationships were evaluated using Spearman correlations. Mid-thigh muscle area (P = 0.31) and lean mass (P = 0.15) did not increase with age and were significantly related to retention of mid-thigh muscle area (P < 0.0001). This occurred despite an increase in total body fat percentage (P = 0.003) with age. Mid-thigh muscle area (P = 0.12), QA (P = 0.17), and quadriceps PT did not decline with age. Specific strength (strength per QA) did not decline significantly with age (P = 0.06). As muscle area increased, PT increased significantly (P = 0.008). There was not a significant relationship between intramuscular adipose tissue (P = 0.71) or lean mass (P = 0.4) and PT. This study contradicts the common observation that muscle mass and strength decline as a function of aging alone. Instead, these declines may signal the effect of chronic disuse rather than muscle aging. Evaluation of masters athletes removes disuse as a confounding variable in the study of lower-extremity function and loss of lean muscle mass. This maintenance of muscle mass and strength may decrease or eliminate the falls, functional decline, and loss of independence that are commonly seen in aging adults.

A Survey of Active Learning Algorithms for Supervised Remote Sensing Image Classification

Defining an efficient training set is one of the most delicate phases for the success of remote sensing image classification routines. The complexity of the problem, the limited temporal and financial resources, as well as the high intraclass variance can make an algorithm fail if it is trained with a suboptimal dataset. Active learning aims at building efficient training sets by iteratively improving the model performance through sampling. A user-defined heuristic ranks the unlabeled pixels according to a function of the uncertainty of their class membership and then the user is asked to provide labels for the most uncertain pixels. This paper reviews and tests the main families of active learning algorithms: committee, large margin, and posterior probability-based. For each of them, the most recent advances in the remote sensing community are discussed and some heuristics are detailed and tested. Several challenging remote sensing scenarios are considered, including very high spatial resolution and hyperspectral image classification. Finally, guidelines for choosing the good architecture are provided for new and/or unexperienced user.

Epidémiologie clinique: définitions, utilités et raisons pour un développement en Suisse. [Clinical epidemiology: definitions, uses and reasons for development in Switzerland].

Clinical epidemiology is the most currently used name for a comparatively new branch of medicine covering a certain number of activities related to the practice of clinical medicine, but using epidemiological techniques and methods. Clinical epidemiology has only just begun to be known in Europe, whereas units are being increasingly developed and expanded in North America, particularly within the clinical departments of hospitals. The methods it offers are valid for both practicing physicians and hospital doctors (or those being trained in hospitals) and serve the purpose of promoting a better quality medical service, especially where a more adequate evaluation of the effectiveness of diagnostic methods, therapy and prognosis in medicine is concerned. Clinical epidemiology proposes a methodology of medical reasoning and of decision-making, as well as techniques intended to facilitate the indispensable task of keeping up with advances in medical knowledge.

Reproducibility and feasibility of a 22 joints ultrasound score in rheumatoid arthritis: a study among rheumatologists with diverse expertise in musculoskeletal ultrasound

Objective: To assess reproducibility and feasibility of amusculoskeletal ultrasound (US) score for rheumatoid arthritis amongrheumatologist with diverse expertise in US, working in private orhospital practice.Methods: The Swiss Sonography in Arthritis and Rheumatism(SONAR) group has developed a semi-quantitative score for RA usingOMERACT criteria for synovitis and erosion. The score was taught torheumatologists trained in US through two workshops. Subsequently,they were encouraged to practice in their office. For the study, we used6 US machines of different quality, each with a different patient.19 readers randomly selected among rheumatologists who haveattended both workshops, were asked to score anonymously at leastone patient. To assess whether some factors influence the score, weasked each reader to answer questionnaire describing his experiencewith US.Results: 19 rheumatologists have performed 29 scans, each patienthaving been evaluated by 4 to 6 readers. Median time for examcompletion was 20 minutes (range 15 to 60 mn). 53% ofrheumatologists work in private practice. Graph 1 show the global greyscale score for each patient. Weighted kappa was calculated for eachpair of reader using stata11. Almost all kappa of poor agreement wereobtained with a low quality device or by an assessor who havepreviously performed less than 5 scores himself.Conclusions: This is the first study to show an US score for RAfeasible by rheumatologists with diverse expertise in US both in privateand hospital practice. Reproducibility seemed to be influenced by thequality of device and previous experience with the score.

Post operative epidural haematomas following spinal surgery : P58

Introduction: Compressive epidural haematomas occurring following spine surgery are very rare but can potentially lead to irreversible damage. The evacuation of the haematoma as an emergency procedure remains the only effective treatment providing though alerting signs are detected on time. Few studies exist on this subject probably due to its rarity. The etiological factors as well as the place of imaging studies prior to urgent haematoma evacuation remain controversial. Two cases of delayed post-operative compressive epidural haematomas following lumbar-spine surgery were detected in our unit between April 2003 and January 2009. In both cases new onset of pain, aggravation of existing neurological deficit or development of new deficit along with worsening of pre-existing walking difficulties were noted. Emergency computer tomography (CT) could not exclude compression in both cases due to important artefacts. Emergency surgery was performed confirming the presence of haematoma in both cases and leading to a complete neurological recovery following its evacuation. As only risk factors common to both cases we identified drain removal and resuming of thromboprophylaxis. Conclusion: Obstacles in early detection of post-operative compressive epidural haematomas occurring following spine surgery are patients presenting with multiple complaints as well as shift work pattern of staff who might not always be trained in detecting early changes in neurological status. We therefore established a checklist for post-operative neurological observations to be carried out on spine surgery patients during the postoperative period. We describe our adopted attitude considering the etiological factors observed in our unit. Further studies including in a multi centre setting would be necessary in order to ascertain our observations.

The value of 'positive' clinical signs for weakness, sensory and gait disorders in conversion disorder: a systematic and narrative review.

Experts in the field of conversion disorder have suggested for the upcoming DSM-V edition to put less weight on the associated psychological factors and to emphasise the role of clinical findings. Indeed, a critical step in reaching a diagnosis of conversion disorder is careful bedside neurological examination, aimed at excluding organic signs and identifying 'positive' signs suggestive of a functional disorder. These positive signs are well known to all trained neurologists but their validity is still not established. The aim of this study is to provide current evidence regarding their sensitivity and specificity. We conducted a systematic search on motor, sensory and gait functional signs in Embase, Medline, PsycINfo from 1965 to June 2012. Studies in English, German or French reporting objective data on more than 10 participants in a controlled design were included in a systematic review. Other relevant signs are discussed in a narrative review. Eleven controlled studies (out of 147 eligible articles) describing 14 signs (7 motor, 5 sensory, 2 gait) reported low sensitivity of 8-100% but high specificity of 92-100%. Studies were evidence class III, only two had a blinded design and none reported on inter-rater reliability of the signs. Clinical signs for functional neurological symptoms are numerous but only 14 have been validated; overall they have low sensitivity but high specificity and their use should thus be recommended, especially with the introduction of the new DSM-V criteria.

Biocurators and biocuration: surveying the 21st century challenges.

Curated databases are an integral part of the tool set that researchers use on a daily basis for their work. For most users, however, how databases are maintained, and by whom, is rather obscure. The International Society for Biocuration (ISB) represents biocurators, software engineers, developers and researchers with an interest in biocuration. Its goals include fostering communication between biocurators, promoting and describing their work, and highlighting the added value of biocuration to the world. The ISB recently conducted a survey of biocurators to better understand their educational and scientific backgrounds, their motivations for choosing a curatorial job and their career goals. The results are reported here. From the responses received, it is evident that biocuration is performed by highly trained scientists and perceived to be a stimulating career, offering both intellectual challenges and the satisfaction of performing work essential to the modern scientific community. It is also apparent that the ISB has at least a dual role to play to facilitate biocurators' work: (i) to promote biocuration as a career within the greater scientific community; (ii) to aid the development of resources for biomedical research through promotion of nomenclature and data-sharing standards that will allow interconnection of biological databases and better exploit the pivotal contributions that biocurators are making. DATABASE URL: http://biocurator.org.

Effects of Intermittent Training on Anaerobic Performance and MCT Transporters in Athletes.

This study examined the effects of intermittent hypoxic training (IHT) on skeletal muscle monocarboxylate lactate transporter (MCT) expression and anaerobic performance in trained athletes. Cyclists were assigned to two interventions, either normoxic (N; n = 8; 150 mmHg PIO2) or hypoxic (H; n = 10; ∼3000 m, 100 mmHg PIO2) over a three week training (5×1 h-1h30.week-1) period. Prior to and after training, an incremental exercise test to exhaustion (EXT) was performed in normoxia together with a 2 min time trial (TT). Biopsy samples from the vastus lateralis were analyzed for MCT1 and MCT4 using immuno-blotting techniques. The peak power output (PPO) increased (p<0.05) after training (7.2% and 6.6% for N and H, respectively), but VO2max showed no significant change. The average power output in the TT improved significantly (7.3% and 6.4% for N and H, respectively). No differences were found in MCT1 and MCT4 protein content, before and after the training in either the N or H group. These results indicate there are no additional benefits of IHT when compared to similar normoxic training. Hence, the addition of the hypoxic stimulus on anaerobic performance or MCT expression after a three-week training period is ineffective.

Dietary supplements utilization: an explanatory survey among Swiss consumers

Dietary supplement (DS) use increased rapidly over the last years. However evidence of benefits of many DS for healthy users are scarce and may not equate known risks of overdose, drug interaction and recently discovered negative long-term effects. Therefore this study aimed to investigate perceptions and motivations of DS users in Lausanne, Switzerland. Method A convenience sample was recruited at the entrance of local sales points. Data were collected in on-site semi-structured interviews to assess dietary supplementation habits. Results The 119 participants provided information on 147 users. Among 273 declared products, the majority were mixed products, containing minerals and vitamins (78), mineral products (69), and herbal products (28). 55% of DS users took more than one product simultaneously. Seventy five percent of participants indicated that DS use presents no risk or nearly no risk and about half (49%) of participants did not inform their physician about their consumption. Male participants reported to share this information with their physicians significantly less frequently than female participants (p = 0.008). About half of participants looked for information on potential risks of DS, men significantly more often than women (p=0.001). Discussion According to other studies in the US, our study shows that, in Lausanne (Switzerland), DS are commonly used as mixed products. Risk perception seems generally low among DS users. Implications Physicians should be trained to evaluate patientsʼ health behaviour and needs in order to provide good evidence based information or propose alternatives to DS use.

Knowledge of Glasgow coma scale by air-rescue physicians.

OBJECTIVE: To assess the theoretical and practical knowledge of the Glasgow Coma Scale (GCS) by trained Air-rescue physicians in Switzerland. METHODS: Prospective anonymous observational study with a specially designed questionnaire. General knowledge of the GCS and its use in a clinical case were assessed. RESULTS: From 130 questionnaires send out, 103 were returned (response rate of 79.2%) and analyzed. Theoretical knowledge of the GCS was consistent for registrars, fellows, consultants and private practitioners active in physician-staffed helicopters. The clinical case was wrongly scored by 38 participants (36.9%). Wrong evaluation of the motor component occurred in 28 questionnaires (27.2%), and 19 errors were made for the verbal score (18.5%). Errors were made most frequently by registrars (47.5%, p = 0.09), followed by fellows (31.6%, p = 0.67) and private practitioners (18.4%, p = 1.00). Consultants made significantly less errors than the rest of the participating physicians (0%, p < 0.05). No statistically significant differences were shown between anesthetists, general practitioners, internal medicine trainees or others. CONCLUSION: Although the theoretical knowledge of the GCS by out-of-hospital physicians is correct, significant errors were made in scoring a clinical case. Less experienced physicians had a higher rate of errors. Further emphasis on teaching the GCS is mandatory.

Syndrome métabolique, diabète sucré et vulnérabilité: une approche "syndémique" de la maladie chronique [Metabolic syndrome, diabetes mellitus and vulnerability: a syndemic approach of chronic diseases].

The pandemic metabolic syndrome is generally attributed to our lifestyle. The current therapeutic strategies are centered on the behavioral changes and pharmacotherapy. A deeply analysis reveals the importance of the socio-cultural determinants with a "dose-responses effect according to the socio-economic level. The "syndemic" theory, which puts at the same level the socio-cultural environment, the behaviors and biomedecine, suggests a more holistic approach. This theory suggests introducing other partners of care, such cultural-mediators and welfare workers trained in the care, to have finally an approach centered on the roots of the causes. The healthcare networks centered on the management of the costs of health should not forget the socio-cultural dimension, unless wanting to select the good cases.

Dynamic visual information plays a critical role for spatial navigation in water but not on solid ground.

In the Morris water maze (MWM) task, proprioceptive information is likely to have a poor accuracy due to movement inertia. Hence, in this condition, dynamic visual information providing information on linear and angular acceleration would play a critical role in spatial navigation. To investigate this assumption we compared rat's spatial performance in the MWM and in the homing hole board (HB) tasks using a 1.5 Hz stroboscopic illumination. In the MWM, rats trained in the stroboscopic condition needed more time than those trained in a continuous light condition to reach the hidden platform. They expressed also little accuracy during the probe trial. In the HB task, in contrast, place learning remained unaffected by the stroboscopic light condition. The deficit in the MWM was thus complete, affecting both escape latency and discrimination of the reinforced area, and was thus task specific. This dissociation confirms that dynamic visual information is crucial to spatial navigation in the MWM whereas spatial navigation on solid ground is mediated by a multisensory integration, and thus less dependent on visual information.

Olfactory and/or visual cues for spatial navigation through ontogeny: olfactory cues enable the use of visual cues

This study analyzed the spatial memory capacities of rats in darkness with visual and/or olfactory cues through ontogeny. Tests were conducted with the homing board, where rats had to find the correct escape hole. Four age groups (24 days, 48 days, 3-6 months, and 12 months) were trained in 3 conditions: (a) 3 identical light cues; (b) 5 different olfactory cues; and (c) both types of cues, followed by removal of the olfactory cues. Results indicate that immature rats first take into account olfactory information but are unable to orient with only the help of discrete visual cues. Olfaction enables the use of visual information by 48-day-old rats. Visual information predominantly supports spatial cognition in adult and 12-month-old rats. Results point out cooperation between vision and olfaction for place navigation during ontogeny in rats.

Are oxygen uptake kinetics modified when using a respiratory snorkel?

PURPOSE: The aim of this study was to compare VO2 kinetics during constant power cycle exercise measured using a conventional facemask (CM) or a respiratory snorkel (RS) designed for breath-by-breath analysis in swimming. METHODS: VO2 kinetics parameters-obtained using CM or RS, in randomized counterbalanced order-were compared in 10 trained triathletes performing two submaximal heavy-intensity cycling square-wave transitions. These VO2 kinetics parameters (ie, time delay: td1, td2; time constant: τ1, τ2; amplitude: A1, A2, for the primary phase and slow component, respectively) were modeled using a double exponential function. In the case of the RS data, this model incorporated an individually determined snorkel delay (ISD). RESULTS: Only td1 (8.9 ± 3.0 vs 13.8 ± 1.8 s, P < .01) differed between CM and RS, whereas all other parameters were not different (τ1 = 24.7 ± 7.6 vs 21.1 ± 6.3 s; A1 = 39.4 ± 5.3 vs 36.8 ± 5.1 mL x min(-1) x kg(-1); td2 = 107.5 ± 87.4 vs 183.5 ± 75.9 s; A2' (relevant slow component amplitude) = 2.6 ± 2.4 vs 3.1 ± 2.6 mL x min(-1) x kg(-1) for CM and RS, respectively). CONCLUSIONS: Although there can be a small mixture of breaths allowed by the volume of the snorkel in the transition to exercise, this does not appear to significantly influence the results. Therefore, given the use of an ISD, the RS is a valid instrument for the determination of VO2 kinetics within submaximal exercise.

Differences in whole-body fat oxidation kinetics between cycling and running.

This study aimed to quantitatively describe and compare whole-body fat oxidation kinetics in cycling and running using a sinusoidal mathematical model (SIN). Thirteen moderately trained individuals (7 men and 6 women) performed two graded exercise tests, with 3-min stages and 1 km h(-1) (or 20 W) increment, on a treadmill and on a cycle ergometer. Fat oxidation rates were determined using indirect calorimetry and plotted as a function of exercise intensity. The SIN model, which includes three independent variables (dilatation, symmetry and translation) that account for main quantitative characteristics of kinetics, provided a mathematical description of fat oxidation kinetics and allowed for determination of the intensity (Fat(max)) that elicits maximal fat oxidation (MFO). While the mean fat oxidation kinetics in cycling formed a symmetric parabolic curve, the mean kinetics during running was characterized by a greater dilatation (i.e., widening of the curve, P < 0.001) and a rightward asymmetry (i.e., shift of the peak of the curve to higher intensities, P = 0.01). Fat(max) was significantly higher in running compared with cycling (P < 0.001), whereas MFO was not significantly different between modes of exercise (P = 0.36). This study showed that the whole-body fat oxidation kinetics during running was characterized by a greater dilatation and a rightward asymmetry compared with cycling. The greater dilatation may be mainly related to the larger muscle mass involved in running while the rightward asymmetry may be induced by the specific type of muscle contraction.