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Lars Henrik Frich - One of the best experts on this subject based on the ideXlab platform.
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supraspinatus and deltoid Muscle Fiber composition in rotator cuff tear conditions
JSES international, 2020Co-Authors: Morten Kjaer Ravn, Trine Ivarsen Ostergaard, Henrik Daa Schroeder, Jens R Nyengaard, Kate Lykke Lambertsen, Lars Henrik FrichAbstract:Background Rotator cuff (RC) tears are associated with RC Muscle atrophy and changes in composition that are crucial to the prognosis of RC repair. The aim of this study was to characterize Muscle Fiber composition in the supraspinatus (SS) Muscle under tear conditions. Methods Muscle biopsies were obtained from 21 patients undergoing surgery for an RC tendon tear. Biopsies were obtained from the musculotendinous junction of the SS Muscle, and control biopsies were harvested from the deltoid Muscle (DT). Biopsies were immunohistochemically processed for detection of type 1 (slow type) and type 2 (fast type) Fibers and analyzed using unbiased, stereological principles. We counted the total numbers of type 1 and 2 Muscle Fibers/mm2, and Fiber diameter was used to estimate Muscle Fiber atrophy and hypertrophy. Results We found significantly more type 2 cells/mm2 in the SS compared with the DT (P Conclusion The changes in the composition of SS Muscle cell types suggest a shift from type 1 to type 2 Muscle Fibers and atrophy of both type 1 and 2 Fibers. This composition indicates loss of endurance and rapid fatigue of the SS Muscle under RC tear conditions.
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supraspinatus and deltoid Muscle Fiber composition in rotator cuff tear conditions
JSES international, 2020Co-Authors: Morten Kjaer Ravn, Trine Ivarsen Ostergaard, Henrik Daa Schroeder, Jens R Nyengaard, Kate Lykke Lambertsen, Lars Henrik FrichAbstract:Background Rotator cuff (RC) tears are associated with RC Muscle atrophy and changes in composition that are crucial to the prognosis of RC repair. The aim of this study was to characterize Muscle Fiber composition in the supraspinatus (SS) Muscle under tear conditions. Methods Muscle biopsies were obtained from 21 patients undergoing surgery for an RC tendon tear. Biopsies were obtained from the musculotendinous junction of the SS Muscle, and control biopsies were harvested from the deltoid Muscle (DT). Biopsies were immunohistochemically processed for detection of type 1 (slow type) and type 2 (fast type) Fibers and analyzed using unbiased, stereological principles. We counted the total numbers of type 1 and 2 Muscle Fibers/mm2, and Fiber diameter was used to estimate Muscle Fiber atrophy and hypertrophy. Results We found significantly more type 2 cells/mm2 in the SS compared with the DT (P < .01). In addition, we found a significantly higher fraction of type 1 Fibers than type 2 Fibers in the DT (P < .01), whereas both Fiber types were equally present in the SS. The diameters of SS cells were generally smaller than those of DT cells. Atrophy of especially SS type 2 Fibers was also demonstrated. Fiber atrophy was more pronounced in men than women. Conclusion The changes in the composition of SS Muscle cell types suggest a shift from type 1 to type 2 Muscle Fibers and atrophy of both type 1 and 2 Fibers. This composition indicates loss of endurance and rapid fatigue of the SS Muscle under RC tear conditions.
Morten Kjaer Ravn - One of the best experts on this subject based on the ideXlab platform.
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supraspinatus and deltoid Muscle Fiber composition in rotator cuff tear conditions
JSES international, 2020Co-Authors: Morten Kjaer Ravn, Trine Ivarsen Ostergaard, Henrik Daa Schroeder, Jens R Nyengaard, Kate Lykke Lambertsen, Lars Henrik FrichAbstract:Background Rotator cuff (RC) tears are associated with RC Muscle atrophy and changes in composition that are crucial to the prognosis of RC repair. The aim of this study was to characterize Muscle Fiber composition in the supraspinatus (SS) Muscle under tear conditions. Methods Muscle biopsies were obtained from 21 patients undergoing surgery for an RC tendon tear. Biopsies were obtained from the musculotendinous junction of the SS Muscle, and control biopsies were harvested from the deltoid Muscle (DT). Biopsies were immunohistochemically processed for detection of type 1 (slow type) and type 2 (fast type) Fibers and analyzed using unbiased, stereological principles. We counted the total numbers of type 1 and 2 Muscle Fibers/mm2, and Fiber diameter was used to estimate Muscle Fiber atrophy and hypertrophy. Results We found significantly more type 2 cells/mm2 in the SS compared with the DT (P Conclusion The changes in the composition of SS Muscle cell types suggest a shift from type 1 to type 2 Muscle Fibers and atrophy of both type 1 and 2 Fibers. This composition indicates loss of endurance and rapid fatigue of the SS Muscle under RC tear conditions.
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supraspinatus and deltoid Muscle Fiber composition in rotator cuff tear conditions
JSES international, 2020Co-Authors: Morten Kjaer Ravn, Trine Ivarsen Ostergaard, Henrik Daa Schroeder, Jens R Nyengaard, Kate Lykke Lambertsen, Lars Henrik FrichAbstract:Background Rotator cuff (RC) tears are associated with RC Muscle atrophy and changes in composition that are crucial to the prognosis of RC repair. The aim of this study was to characterize Muscle Fiber composition in the supraspinatus (SS) Muscle under tear conditions. Methods Muscle biopsies were obtained from 21 patients undergoing surgery for an RC tendon tear. Biopsies were obtained from the musculotendinous junction of the SS Muscle, and control biopsies were harvested from the deltoid Muscle (DT). Biopsies were immunohistochemically processed for detection of type 1 (slow type) and type 2 (fast type) Fibers and analyzed using unbiased, stereological principles. We counted the total numbers of type 1 and 2 Muscle Fibers/mm2, and Fiber diameter was used to estimate Muscle Fiber atrophy and hypertrophy. Results We found significantly more type 2 cells/mm2 in the SS compared with the DT (P < .01). In addition, we found a significantly higher fraction of type 1 Fibers than type 2 Fibers in the DT (P < .01), whereas both Fiber types were equally present in the SS. The diameters of SS cells were generally smaller than those of DT cells. Atrophy of especially SS type 2 Fibers was also demonstrated. Fiber atrophy was more pronounced in men than women. Conclusion The changes in the composition of SS Muscle cell types suggest a shift from type 1 to type 2 Muscle Fibers and atrophy of both type 1 and 2 Fibers. This composition indicates loss of endurance and rapid fatigue of the SS Muscle under RC tear conditions.
Christopher L Mendias - One of the best experts on this subject based on the ideXlab platform.
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changes in Muscle Fiber contractility and extracellular matrix production during skeletal Muscle hypertrophy
Journal of Applied Physiology, 2017Co-Authors: Christopher L Mendias, Andrew J Schwartz, Jeremy A Grekin, Jonathan P Gumucio, Kristoffer B SuggAbstract:This study utilized a rat synergist ablation model to integrate changes in single Muscle Fiber contractility, extracellular matrix composition, activation of important signaling pathways in Muscle ...
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reduced Muscle Fiber force production and disrupted myofibril architecture in patients with chronic rotator cuff tears
Journal of Shoulder and Elbow Surgery, 2015Co-Authors: Christopher L Mendias, Stuart M Roche, Max E Davis, Evan B Lynch, Julie A Harning, Elizabeth Sibilsky R Enselman, Jon A Jacobson, Dennis R Claflin, Sarah Calve, Asheesh BediAbstract:Background A persistent atrophy of Muscle Fibers and an accumulation of fat, collectively referred to as fatty degeneration, commonly occur in patients with chronic rotator cuff tears. The etiology of fatty degeneration and function of the residual rotator cuff musculature have not been well characterized in humans. We hypothesized that Muscles from patients with chronic rotator cuff tears have reduced Muscle Fiber force production, disordered myofibrils, and an accumulation of fat vacuoles. Methods The contractility of Muscle Fibers from biopsy specimens of supraspinatus Muscles of 13 patients with chronic full-thickness posterosuperior rotator cuff tears was measured and compared with data from healthy vastus lateralis Muscle Fibers. Correlations between Muscle Fiber contractility, American Shoulder and Elbow Surgeons (ASES) scores, and tear size were analyzed. Histology and electron microscopy were also performed. Results Torn supraspinatus Muscles had a 30% reduction in maximum isometric force production and a 29% reduction in normalized force compared with controls. Normalized supraspinatus Fiber force positively correlated with ASES score and negatively correlated with tear size. Disordered sarcomeres were noted, along with an accumulation of lipid-laden macrophages in the extracellular matrix surrounding supraspinatus Muscle Fibers. Conclusions Patients with chronic supraspinatus tears have significant reductions in Muscle Fiber force production. Force production also correlates with ASES scores and tear size. The structural and functional Muscle dysfunction of the residual Muscle Fibers is independent of the additional area taken up by fibrotic tissue. This work may help establish future therapies to restore Muscle function after the repair of chronically torn rotator cuff Muscles.
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patients with chronic myosteatosis have a reduction in Muscle Fiber force production and disrupted myofibril architecture 1163 18
The FASEB Journal, 2014Co-Authors: Christopher L Mendias, Stuart M Roche, Max E Davis, Evan B Lynch, Asheesh BediAbstract:A persistent atrophy of Muscle Fibers and an accumulation of fat, collectively referred to as myosteatosis, commonly occurs in patients with chronic Muscle tears. The rotator cuff Muscle group develops substantial myosteatosis after chronic tears, and patients with these injuries often have marked reductions in upper extremity function and quality of life. As the etiology of myosteatosis has not been well characterized in humans, our objective was to determine changes in Muscle Fiber structure and function in patients with chronic rotator cuff tears. We hypothesized that Muscles from patients with chronic rotator cuff tears have reduced Muscle Fiber force production, disordered myofibrils and an accumulation of inflammatory macrophages. Compared with control Muscles, there was no difference in Muscle Fiber cross-sectional area, but torn supraspinatus Muscles had a 30% reduction in maximum isometric force production and a 29% reduction in normalized force. Using electron microscopy and histology, disordere...
Asheesh Bedi - One of the best experts on this subject based on the ideXlab platform.
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reduced Muscle Fiber force production and disrupted myofibril architecture in patients with chronic rotator cuff tears
Journal of Shoulder and Elbow Surgery, 2015Co-Authors: Christopher L Mendias, Stuart M Roche, Max E Davis, Evan B Lynch, Julie A Harning, Elizabeth Sibilsky R Enselman, Jon A Jacobson, Dennis R Claflin, Sarah Calve, Asheesh BediAbstract:Background A persistent atrophy of Muscle Fibers and an accumulation of fat, collectively referred to as fatty degeneration, commonly occur in patients with chronic rotator cuff tears. The etiology of fatty degeneration and function of the residual rotator cuff musculature have not been well characterized in humans. We hypothesized that Muscles from patients with chronic rotator cuff tears have reduced Muscle Fiber force production, disordered myofibrils, and an accumulation of fat vacuoles. Methods The contractility of Muscle Fibers from biopsy specimens of supraspinatus Muscles of 13 patients with chronic full-thickness posterosuperior rotator cuff tears was measured and compared with data from healthy vastus lateralis Muscle Fibers. Correlations between Muscle Fiber contractility, American Shoulder and Elbow Surgeons (ASES) scores, and tear size were analyzed. Histology and electron microscopy were also performed. Results Torn supraspinatus Muscles had a 30% reduction in maximum isometric force production and a 29% reduction in normalized force compared with controls. Normalized supraspinatus Fiber force positively correlated with ASES score and negatively correlated with tear size. Disordered sarcomeres were noted, along with an accumulation of lipid-laden macrophages in the extracellular matrix surrounding supraspinatus Muscle Fibers. Conclusions Patients with chronic supraspinatus tears have significant reductions in Muscle Fiber force production. Force production also correlates with ASES scores and tear size. The structural and functional Muscle dysfunction of the residual Muscle Fibers is independent of the additional area taken up by fibrotic tissue. This work may help establish future therapies to restore Muscle function after the repair of chronically torn rotator cuff Muscles.
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patients with chronic myosteatosis have a reduction in Muscle Fiber force production and disrupted myofibril architecture 1163 18
The FASEB Journal, 2014Co-Authors: Christopher L Mendias, Stuart M Roche, Max E Davis, Evan B Lynch, Asheesh BediAbstract:A persistent atrophy of Muscle Fibers and an accumulation of fat, collectively referred to as myosteatosis, commonly occurs in patients with chronic Muscle tears. The rotator cuff Muscle group develops substantial myosteatosis after chronic tears, and patients with these injuries often have marked reductions in upper extremity function and quality of life. As the etiology of myosteatosis has not been well characterized in humans, our objective was to determine changes in Muscle Fiber structure and function in patients with chronic rotator cuff tears. We hypothesized that Muscles from patients with chronic rotator cuff tears have reduced Muscle Fiber force production, disordered myofibrils and an accumulation of inflammatory macrophages. Compared with control Muscles, there was no difference in Muscle Fiber cross-sectional area, but torn supraspinatus Muscles had a 30% reduction in maximum isometric force production and a 29% reduction in normalized force. Using electron microscopy and histology, disordere...
Trine Ivarsen Ostergaard - One of the best experts on this subject based on the ideXlab platform.
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supraspinatus and deltoid Muscle Fiber composition in rotator cuff tear conditions
JSES international, 2020Co-Authors: Morten Kjaer Ravn, Trine Ivarsen Ostergaard, Henrik Daa Schroeder, Jens R Nyengaard, Kate Lykke Lambertsen, Lars Henrik FrichAbstract:Background Rotator cuff (RC) tears are associated with RC Muscle atrophy and changes in composition that are crucial to the prognosis of RC repair. The aim of this study was to characterize Muscle Fiber composition in the supraspinatus (SS) Muscle under tear conditions. Methods Muscle biopsies were obtained from 21 patients undergoing surgery for an RC tendon tear. Biopsies were obtained from the musculotendinous junction of the SS Muscle, and control biopsies were harvested from the deltoid Muscle (DT). Biopsies were immunohistochemically processed for detection of type 1 (slow type) and type 2 (fast type) Fibers and analyzed using unbiased, stereological principles. We counted the total numbers of type 1 and 2 Muscle Fibers/mm2, and Fiber diameter was used to estimate Muscle Fiber atrophy and hypertrophy. Results We found significantly more type 2 cells/mm2 in the SS compared with the DT (P Conclusion The changes in the composition of SS Muscle cell types suggest a shift from type 1 to type 2 Muscle Fibers and atrophy of both type 1 and 2 Fibers. This composition indicates loss of endurance and rapid fatigue of the SS Muscle under RC tear conditions.
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supraspinatus and deltoid Muscle Fiber composition in rotator cuff tear conditions
JSES international, 2020Co-Authors: Morten Kjaer Ravn, Trine Ivarsen Ostergaard, Henrik Daa Schroeder, Jens R Nyengaard, Kate Lykke Lambertsen, Lars Henrik FrichAbstract:Background Rotator cuff (RC) tears are associated with RC Muscle atrophy and changes in composition that are crucial to the prognosis of RC repair. The aim of this study was to characterize Muscle Fiber composition in the supraspinatus (SS) Muscle under tear conditions. Methods Muscle biopsies were obtained from 21 patients undergoing surgery for an RC tendon tear. Biopsies were obtained from the musculotendinous junction of the SS Muscle, and control biopsies were harvested from the deltoid Muscle (DT). Biopsies were immunohistochemically processed for detection of type 1 (slow type) and type 2 (fast type) Fibers and analyzed using unbiased, stereological principles. We counted the total numbers of type 1 and 2 Muscle Fibers/mm2, and Fiber diameter was used to estimate Muscle Fiber atrophy and hypertrophy. Results We found significantly more type 2 cells/mm2 in the SS compared with the DT (P < .01). In addition, we found a significantly higher fraction of type 1 Fibers than type 2 Fibers in the DT (P < .01), whereas both Fiber types were equally present in the SS. The diameters of SS cells were generally smaller than those of DT cells. Atrophy of especially SS type 2 Fibers was also demonstrated. Fiber atrophy was more pronounced in men than women. Conclusion The changes in the composition of SS Muscle cell types suggest a shift from type 1 to type 2 Muscle Fibers and atrophy of both type 1 and 2 Fibers. This composition indicates loss of endurance and rapid fatigue of the SS Muscle under RC tear conditions.
