1,721,529 research outputs found
Influence of physical activity on structure and function of the RyR1 calcium channel: A systematic review
No full textINTRODUCTION: Calcium release through ryanodine receptor type 1 (RyR1) channel triggers skeletal muscle contraction, which is finely regulated during physical activity allowing muscles to adapt to stress. However, both prolonged physical activity and inactivity decrease contractile function. The adaptive mechanisms are related to changes in structure, function, and expression of RyR1 channel. EVIDENCE ACQUISITION: The search on the effects of physical activities on RyR1 structure and function covered PubMed and Scopus databases from 2008 onward. The search term used was RyR1 combined with exercise, fatigue, exertional rhabdomyolysis, or aging. EVIDENCE SYNTHESIS: Physical activity induces RyR1 dynamic post-translational modifications, driven essentially by increased reactive oxygen and nitrogen species. RyR1 redox-dependent modifications increase channel activity, but impaired Ca2+ handling may lead to muscle fatigue. Furthermore, imbalance of redox equilibrium may induce RyR1 fragmentation. During exercise RyR1 is also hyperphosphorylated and dissociated from its stabilizing subunit calstabin1, resulting in “leaky” channels and decreased exercise tolerance. RyR1 modifications also occur during aging. Conversely, reduced RyR1 protein expression occurs in some pathophysiological conditions characterized by low-exercise capacity, i.e., heart failure and prolonged bed rest. Impaired muscle performance is also linked to RyR1 mutations, with altered channel structure and/or function. Moreover, in apparently healthy subjects with RyR1 mutations, physical exercise can trigger skeletal muscle stiffness at low temperatures, or exertional rhabdomyolysis. CONCLUSIONS: We provide an overview of the molecular aspects linking skeletal muscle activity to RyR1 modifications, with particular attention to the effects produced by different type of exercises, i.e. aerobic and anaerobic exercise, by some pathophysiological conditions, by age-related loss of muscle function and by RyR1 mutations
Studio comparativo fra bufali e bovini sulla qualità della carne. VII. Caratteristiche mioreologiche all'età di 36 settimane
No full textLo studio è stato condotto su 13 muscoli prelevati dalla mezzena destra di 10 bufali e di 10 bovini Frisoni italiani allevati in identiche condizioni microambientali e macellati all'età di 36 settimane. I risultati piú importanti possono essere così sintetizzati:
(a) il muscolo, sia indipendentemente che entro la specie, risulta una importante fonte di variazione per quasi tutte le caratteristiche tessurometriche considerate;
(b) l'interazione ‘specie x muscolo’ non risulta statisticamente significativa;
(c) in ambedue le specie i muscoli tendono a conservare la stessa posizione ordinale per quasi tutti i parametri (W di Kendall);
(d) la carne bufalina tende ad essere qualitativamente superiore a quella bovina: piú tenera (12 per cento), richiedente un minor lavoro di masticazione (14 per cento) e con un maggior potere di ritenzione dell’acqua (6 per cento)
Physiopathology and treatment of anastomotic ulcer: An emerging pathology?
No full textAnastomotic ulcer in the upper gastrointestinal tract is a relatively infrequent lesion which generally occurs in gastrojejunal anastomosis. Different alterations have been involved in its pathogenesis, which likely remains multifactorial. Several risk factors have been identified, including NSAID use and smoking habit, while postoperative proton pump inhibitor therapy exerts a protective effect. Data on the potential role of H. pylori are still controversial, and further well-designed studies are needed. Improvement of surgical technique (absorbable suture, small pouch, reinforced stapler, etc.) could reduce the incidence of marginal ulcer. Novel therapies based on perianastomotic injection with different stimulating factors showed promising results in experimental models. The marginal ulcer may remain asymptomatic or cause different symptoms requiring a prompt upper endoscopy. Prolonged proton pump inhibitor therapy seems to be the best medical approach, and the ulcer healing need to be confirmed. Indeed, some patients may experience an ulcer complication (bleeding, perforation, and stenosis) requiring either an endoscopic or a surgical approach in selected cases
Ciliary Disfunction Underlies Cystic Kidney in Oral-Facial-Digital Type I (OFD1) Syndrome
No full text
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
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