1,720,960 research outputs found
Effects of repeated High-Intensity Interval Training interventions on oxidative metabolism adaptations in human skeletal muscle
Full text linkSkeletal muscle is a highly plastic tissue. Exercise is a powerful stimulus that can remodel skeletal muscle by activating signalling pathways that change its metabolism and contractile properties. Resistance training is an effective intervention strategy to improve strength and muscle hypertrophy. It has been shown that an initial exposure to a hypertrophic stimulus leads to faster and greater growth of skeletal muscle if repeated subsequently. The permanence of acquired myonuclei and conserved epigenetic modifications are parallel processes that appear to be involved in the phenomenon known as 'muscle memory'.
Endurance exercise is a strong tool for modulating mitochondrial biogenesis. Acute high-intensity endurance exercise has been shown to promote epigenetic modifications and gene expression of mitochondrial biomarkers compared to low-intensity exercise.
This thesis aimed to understand whether oxidative metabolism adapts to repeated aerobic exercise training interventions retaining adaptations over time.
To achieve this goal twenty healthy young subjects (25 ± 5 years) underwent two repeated high-intensity interval training (HIIT) interventions (training and retraining), separated by 12 weeks of detraining. The training intervention consisted of 8 weeks of combined high-intensity cycling and interval sprint exercise performed 3 days per week.
In-vivo peak oxygen consumption (V̇O2peak) and peak power output (Wpeak) significantly improved during both training and retraining, but increment changes were not different between the two interventions. No change in ex-vivo mitochondrial respiration was found both after training and retraining.
Muscle capillarization (capillary density) and endothelial function (CD31 protein expression) were improved after training and retraining intervention. Interestingly, the increase in CD31 content was retained during detraining.
Mitochondrial biogenesis markers (CS, PGC1α and ANT1 protein content) showed a tendency to increase after training, which became significantly higher after retraining.
Mitochondrial dynamic markers showed a pro-fusion adaptation both after training and retraining based on the significant increase of OPA1, MFN2 and MFN1 protein content. MFN1 showed a tendency to increase after training, which became significantly higher after retraining. At the molecular level, these data show that retraining effects appear to be modulated by the first training, suggesting a potential muscle memory mechanism triggered by endurance exercise.
Considering that single fibres cross-sectional area has not been affected by the repeated HIIT interventions, thereby excluding the presence of hypertrophy and the addition of new myonuclei, we investigated the potential presence of an epigenetic memory mechanism. Genome-wide DNA methylation analysis identified differentially methylated positions (DMPs) induced by training. Two epigenetic memory profiles were revealed, characterized by the maintenance of hypomethylation even during prolonged detraining, and involving differentially methylated regions related to genes involved in skeletal muscle metabolic pathways. Six genes were identified as epigenetic memory genes with increased transcript expression after training, which was maintained after detraining and retraining. Since the retention of transcript expression was also observed in genes involved in lactate transport (SLC16A3), biomarkers of lactate transport (MCT1, MCT4, LDH) were studied. After retraining, MCT1 protein content increased compared to baseline, showing a memory profile at the level of protein expression.
These data provided evidence for a skeletal muscle memory mechanism, elicited by high-intensity aerobic training
A short-term treatment with resveratrol improves the inflammatory conditions of Middle-aged mice skeletal muscles
No full textSarcopenia starts around the age of 40, causes the loss of 8% of muscle mass every 10 years, and is accompanied by functional deficit, chronic low-grade inflammation, and can result in several negative health outcomes. Considering the early and gradual onset of sarcopenia, the time window of the potential interventions could be crucial for the exertion of a beneficial effect. We recently showed that the long-term supplementation with Resveratrol contrasts sarcopenia in naturally ageing C57BL/6 mice. Aiming to understand the effects of a short term treatment, we administered intraperitoneally middle aged male mice with 20 mg/kg body weight Resveratrol daily for 5 weeks. Although we could not observe major differences in the histological properties of SKMs, we detected a significant decrease of Cox-2 in RES-treated muscles, confirming the antiinflammatory action of Resveratrol, and suggesting that its anti-inflammatory action precedes modifications to SKM fibres
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
Appropriate 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
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
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