1,720,973 research outputs found
Metabolic myopathies: functional evaluation by analysis of oxygen uptake kinetics.
No full textPURPOSE: The aim was to identify additional noninvasive tools allowing to detect and to quantify the metabolic impairment in patients with mitochondrial myopathies (MM) or McArdle's disease (McA). METHODS: Kinetics of adjustment of pulmonary oxygen uptake (V̇O2 kinetics) during transitions to constant-load moderate-intensity cycle ergometer exercise were determined on 15 MM, 8 McA, 21 patients with signs and/or symptoms of metabolic myopathy but a negative biopsy ("patient controls"; P-CTRL), and 22 healthy untrained controls (CTRL). RESULTS: V̇O2 kinetics were slower in MM and in McA versus P-CTRL and CTRL, slower in McA versus MM, and not significantly different between P-CTRL and CTRL. The time constants (τ) of the monoexponential function describing the V̇O2 kinetics were (X̄ ± SE) 59.2 ± 8.5 s in MM, 87.6 ± 16.4 s in McA, 36.9 ± 3.1 s in P-CTRL, and 35.4 ± 1.9 s in CTRL. In a subgroup of the patients (eight MM and seven McA), τ of V̇O2 kinetics were negatively correlated with two variables determined in a previous study (Grassi B, Marzorati M, Lanfranconi F, et al. Impaired oxygen extraction in metabolic myopathies: detection and quantification by near-infrared spectroscopy. Muscle Nerve. 2007;35:510-20): a) a muscle oxygenation index, obtained by near-infrared spectroscopy, estimating the peak capacity of skeletal muscle fractional O2 extraction; and b) V̇O2 peak. CONCLUSIONS: In MM and McA patients, analysis of pulmonary V̇O2 kinetics during moderate-intensity exercise allows to identify and to quantify, noninvasively, the impairment of skeletal muscle oxidative metabolism. In these patients, the slower V̇O2 kinetics can be considered a marker of the impaired exercise tolerance. The present data could be useful for clinicians who need an objective, quantitative, and longitudinal evaluation of the impairment to be used in the follow-up of these patients as well as in the assessment of therapeutic interventions. © 2009 by the American College of Sports Medicine
Cardiac denervation does/does not play a major role in exercise limitation after heart transplantation [4]
No full textFollow-up of Acute Respiratory Disorders in Cyclists Competing in the 100th Giro d’Italia
No full textAcute respiratory disorder is a common sub-clinical condition affecting elite cyclists. Monitoring the perturbations of the immunological cells in the respiratory tract, indicative of a likely proinflammatory state, during an International Cycling Union world tour is a challenging task. The aim of this study was to follow up on the sign and symptoms of upper way respiratory infections with or without asthma, using non-invasive methods, during a 21-day race (100 ° Giro d’Italia, 2017). Nine male elite cyclists of the Bahrain Merida Team were evaluated before the training season and daily during the race. Clinical history, skin prick and spirometric test, acute respiratory symptoms were measured using validated questionnaires, and values of fraction of exhaled nitric oxide were collected longitudinally. Four of the 9 athletes had allergies with/or consistent abnormal spirometric curves before the race. During the race, 5 athletes had a fraction of exhaled nitric oxide values > 20 ppb which correlated with respiratory symptoms collected through questionnaires. These were related to the environmental characteristics of the places travelled through in the race. The athletes with a predisposition to chronic respiratory inflammation in the pre-competitive season were more likely to develop acute respiratory symptoms during the rac
Role of skeletal muscles impairment and brain oxygenation in limiting oxidative metabolism during exercise after bed rest
No full text"Central" and "peripheral" limitations to oxidative metabolism during exercise were evaluated in 10 young males following a 35-day horizontal bed rest (BR). Incremental exercise (IE) and moderate- and heavy-intensity constant-load exercises (CLE) were carried out on a cycloergometer before and 1-2 days after BR. Pulmonary gas exchange, cardiac output (Q; by impedance cardiography), skeletal muscle (vastus lateralis), and brain (frontal cortex) oxygenation (by near-infrared spectroscopy) were determined. After BR, "peak" (values at exhaustion during IE) workload, peak O(2) uptake (Vo(2 peak)), peak stroke volume, Q(peak), and peak skeletal muscle O(2) extraction were decreased (-18, -18, -22, -19, and -33%, respectively). The gas exchange threshold was approximately 60% of Vo(2 peak) both before and after BR. At the highest workloads, brain oxygenation data suggest an increased O(2) extraction, which was unaffected by BR. Vo(2) kinetics during CLE (same percentage of peak workload before and after BR) were slower (time constant of the "fundamental" component: 31.1 +/- 2.0 s before vs. 40.0 +/- 2.2 s after BR); the amplitude of the "slow component" was unaffected by BR, thus it would be greater, after BR, at the same absolute workload. A more pronounced "overshoot" of skeletal muscle O(2) extraction during CLE was observed after BR, suggesting an impaired adjustment of skeletal muscle O(2) delivery. The role of skeletal muscles in the impairment of oxidative metabolism during submaximal and maximal exercise after BR was identified. The reduced capacity of peak cardiovascular O(2) delivery did not determine a "competition" for the available O(2) between skeletal muscles and brain
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Insights into cental and peripheral factors affacting the "oxidative performance" of skeletal muscle in aging
No full textAppropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Possibilità di incrementare criticamente la cultura alimentare e di medicina dello sport in atleti agonisti e preparatori atletici
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