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Raffaele Lodi - One of the best experts on this subject based on the ideXlab platform.
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The role of pH on the thermodynamics and kinetics of Muscle Biochemistry: An in vivo study by 31P-MRS in patients with myo-phosphorylase deficiency
Biochimica et biophysica acta, 2011Co-Authors: Emil Malucelli, Stefano Iotti, David Neil Manners, Claudia Testa, Andrea Martinuzzi, Bruno Barbiroli, Raffaele LodiAbstract:Abstract In this study we assessed ΔG′ATP hydrolysis, cytosolic [ADP], and the rate of phosphocreatine recovery using Phosphorus Magnetic Resonance Spectroscopy in the calf Muscle of a group of patients affected by glycogen myo-phosphorylase deficiency (McArdle disease). The goal was to ascertain whether and to what extent the deficit of the glycogenolytic pathway would affect the Muscle energy balance. A typical feature of this pathology is the lack of intracellular acidosis. Therefore we posed the question of whether, in the absence of pH decrease, the rate of phosphocreatine recovery depends on the amount of phosphocreatine consumed during exercise. Results showed that at the end of exercise both [ADP] and ΔG′ATP of patients were significantly higher than those of matched control groups reaching comparable levels of phosphocreatine concentration. Furthermore, in these patients we found that the rate of phosphocreatine recovery is not influenced by the amount of phosphocreatine consumed during exercise. These outcomes provide experimental evidence that: i) the intracellular acidification occurring in exercising skeletal Muscle is a protective factor for the energy consumption; and ii) the influence of pH on the phosphocreatine recovery rate is at least in part related to the kinetic mechanisms of mitochondrial creatine kinase enzyme.
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The role of pH on the thermodynamics and kinetics of Muscle Biochemistry: An in vivo study by ³¹P-MRS in patients with myo-phosphorylase deficiency Bioenergetics
Biochimica et Biophysica Acta, 2011Co-Authors: Emil Malucelli, Stefano Iotti, David Neil Manners, Claudia Testa, Andrea Martinuzzi, Bruno Barbiroli, Raffaele LodiAbstract:In this study we assessed ΔG′ATP hydrolysis, cytosolic [ADP], and the rate of phosphocreatine recovery using Phosphorus Magnetic Resonance Spectroscopy in the calf Muscle of a group of patients affected by glycogen myo-phosphorylase deficiency (McArdle disease). The goal was to ascertain whether and to what extent the deficit of the glycogenolytic pathway would affect the Muscle energy balance. A typical feature of this pathology is the lack of intracellular acidosis. Therefore we posed the question of whether, in the absence of pH decrease, the rate of phosphocreatine recovery depends on the amount of phosphocreatine consumed during exercise. Results showed that at the end of exercise both [ADP] and ΔG′ATP of patients were significantly higher than those of matched control groups reaching comparable levels of phosphocreatine concentration. Furthermore, in these patients we found that the rate of phosphocreatine recovery is not influenced by the amount of phosphocreatine consumed during exercise. These outcomes provide experimental evidence that: i) the intracellular acidification occurring in exercising skeletal Muscle is a protective factor for the energy consumption; and ii) the influence of pH on the phosphocreatine recovery rate is at least in part related to the kinetic mechanisms of mitochondrial creatine kinase enzyme.
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the role of ph on the thermodynamics and kinetics of Muscle Biochemistry an in vivo study by p mrs in patients with myo phosphorylase deficiency bioenergetics
Biochimica et Biophysica Acta, 2011Co-Authors: Emil Malucelli, Stefano Iotti, David Neil Manners, Claudia Testa, Andrea Martinuzzi, Bruno Barbiroli, Raffaele LodiAbstract:In this study we assessed ΔG′ATP hydrolysis, cytosolic [ADP], and the rate of phosphocreatine recovery using Phosphorus Magnetic Resonance Spectroscopy in the calf Muscle of a group of patients affected by glycogen myo-phosphorylase deficiency (McArdle disease). The goal was to ascertain whether and to what extent the deficit of the glycogenolytic pathway would affect the Muscle energy balance. A typical feature of this pathology is the lack of intracellular acidosis. Therefore we posed the question of whether, in the absence of pH decrease, the rate of phosphocreatine recovery depends on the amount of phosphocreatine consumed during exercise. Results showed that at the end of exercise both [ADP] and ΔG′ATP of patients were significantly higher than those of matched control groups reaching comparable levels of phosphocreatine concentration. Furthermore, in these patients we found that the rate of phosphocreatine recovery is not influenced by the amount of phosphocreatine consumed during exercise. These outcomes provide experimental evidence that: i) the intracellular acidification occurring in exercising skeletal Muscle is a protective factor for the energy consumption; and ii) the influence of pH on the phosphocreatine recovery rate is at least in part related to the kinetic mechanisms of mitochondrial creatine kinase enzyme.
Emil Malucelli - One of the best experts on this subject based on the ideXlab platform.
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The role of pH on the thermodynamics and kinetics of Muscle Biochemistry: An in vivo study by 31P-MRS in patients with myo-phosphorylase deficiency
Biochimica et biophysica acta, 2011Co-Authors: Emil Malucelli, Stefano Iotti, David Neil Manners, Claudia Testa, Andrea Martinuzzi, Bruno Barbiroli, Raffaele LodiAbstract:Abstract In this study we assessed ΔG′ATP hydrolysis, cytosolic [ADP], and the rate of phosphocreatine recovery using Phosphorus Magnetic Resonance Spectroscopy in the calf Muscle of a group of patients affected by glycogen myo-phosphorylase deficiency (McArdle disease). The goal was to ascertain whether and to what extent the deficit of the glycogenolytic pathway would affect the Muscle energy balance. A typical feature of this pathology is the lack of intracellular acidosis. Therefore we posed the question of whether, in the absence of pH decrease, the rate of phosphocreatine recovery depends on the amount of phosphocreatine consumed during exercise. Results showed that at the end of exercise both [ADP] and ΔG′ATP of patients were significantly higher than those of matched control groups reaching comparable levels of phosphocreatine concentration. Furthermore, in these patients we found that the rate of phosphocreatine recovery is not influenced by the amount of phosphocreatine consumed during exercise. These outcomes provide experimental evidence that: i) the intracellular acidification occurring in exercising skeletal Muscle is a protective factor for the energy consumption; and ii) the influence of pH on the phosphocreatine recovery rate is at least in part related to the kinetic mechanisms of mitochondrial creatine kinase enzyme.
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The role of pH on the thermodynamics and kinetics of Muscle Biochemistry: An in vivo study by ³¹P-MRS in patients with myo-phosphorylase deficiency Bioenergetics
Biochimica et Biophysica Acta, 2011Co-Authors: Emil Malucelli, Stefano Iotti, David Neil Manners, Claudia Testa, Andrea Martinuzzi, Bruno Barbiroli, Raffaele LodiAbstract:In this study we assessed ΔG′ATP hydrolysis, cytosolic [ADP], and the rate of phosphocreatine recovery using Phosphorus Magnetic Resonance Spectroscopy in the calf Muscle of a group of patients affected by glycogen myo-phosphorylase deficiency (McArdle disease). The goal was to ascertain whether and to what extent the deficit of the glycogenolytic pathway would affect the Muscle energy balance. A typical feature of this pathology is the lack of intracellular acidosis. Therefore we posed the question of whether, in the absence of pH decrease, the rate of phosphocreatine recovery depends on the amount of phosphocreatine consumed during exercise. Results showed that at the end of exercise both [ADP] and ΔG′ATP of patients were significantly higher than those of matched control groups reaching comparable levels of phosphocreatine concentration. Furthermore, in these patients we found that the rate of phosphocreatine recovery is not influenced by the amount of phosphocreatine consumed during exercise. These outcomes provide experimental evidence that: i) the intracellular acidification occurring in exercising skeletal Muscle is a protective factor for the energy consumption; and ii) the influence of pH on the phosphocreatine recovery rate is at least in part related to the kinetic mechanisms of mitochondrial creatine kinase enzyme.
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the role of ph on the thermodynamics and kinetics of Muscle Biochemistry an in vivo study by p mrs in patients with myo phosphorylase deficiency bioenergetics
Biochimica et Biophysica Acta, 2011Co-Authors: Emil Malucelli, Stefano Iotti, David Neil Manners, Claudia Testa, Andrea Martinuzzi, Bruno Barbiroli, Raffaele LodiAbstract:In this study we assessed ΔG′ATP hydrolysis, cytosolic [ADP], and the rate of phosphocreatine recovery using Phosphorus Magnetic Resonance Spectroscopy in the calf Muscle of a group of patients affected by glycogen myo-phosphorylase deficiency (McArdle disease). The goal was to ascertain whether and to what extent the deficit of the glycogenolytic pathway would affect the Muscle energy balance. A typical feature of this pathology is the lack of intracellular acidosis. Therefore we posed the question of whether, in the absence of pH decrease, the rate of phosphocreatine recovery depends on the amount of phosphocreatine consumed during exercise. Results showed that at the end of exercise both [ADP] and ΔG′ATP of patients were significantly higher than those of matched control groups reaching comparable levels of phosphocreatine concentration. Furthermore, in these patients we found that the rate of phosphocreatine recovery is not influenced by the amount of phosphocreatine consumed during exercise. These outcomes provide experimental evidence that: i) the intracellular acidification occurring in exercising skeletal Muscle is a protective factor for the energy consumption; and ii) the influence of pH on the phosphocreatine recovery rate is at least in part related to the kinetic mechanisms of mitochondrial creatine kinase enzyme.
Geert H Geesink - One of the best experts on this subject based on the ideXlab platform.
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contribution of postmortem Muscle Biochemistry to the delivery of consistent meat quality with particular focus on the calpain system
Meat Science, 2006Co-Authors: Mohammad Koohmaraie, Geert H GeesinkAbstract:Tenderness has been repeatedly reported as the most important quality aspect of meat. However, a number of studies have shown that a significant portion of retail meat can be considered tough. As a consequence, a significant consumer segment is willing to pay a premium for guaranteed tender meat. However, apart from measuring the shear force, there is no reliable method to predict tenderness. Most of the branded meat programs therefore attempt to ensure eating quality by controlling some of the factors that affect tenderness. Meat tenderness is determined by the amount and solubility of connective tissue, sarcomere shortening during rigor development, and postmortem proteolysis of myofibrillar and myofibrillar-associated proteins. Given the effect of postmortem proteolysis on the Muscle ultrastructure, titin and desmin are likely key substrates that determine meat tenderness. A large number of studies have shown that the calpain proteolytic system plays a central role in postmortem proteolysis and tenderization. In skeletal Muscle, the calpain system consists of at least three proteases, l-calpain, m-calpain and calpain 3, and an inhibitor of l- and m-calpain, calpastatin. When activated by calcium, the calpains not only degrade subtrates, but also autolyze, leading to loss of activity. m-Calpain does not autolyze in postmortem Muscle and is therefore not involved in postmortem tenderization. Results from a number of studies, including a study on calpain 3 knockout mice, have shown that calpain 3 is also not involved in postmortem proteolysis. However, a large number of studies, including a study on l-calpain knockout mice, have shown that l-calpain is largely, if not solely, responsible for postmortem tenderization. Research efforts in this area should, therefore, focus on elucidation of regulation of lcalpain activity in postmortem Muscle. Discovering the mechanisms of l-calpain activity regulation and methods to promote l-calpain activity should have a dramatic effect on the ability of researchers to develop reliable methods to predict meat tenderness and on the meat industry to produce a consistently tender product. Published by Elsevier Ltd.
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Contribution of postmortem Muscle Biochemistry to the delivery of consistent meat quality with particular focus on the calpain system
Meat science, 2006Co-Authors: Mohammad Koohmaraie, Geert H GeesinkAbstract:Tenderness has been repeatedly reported as the most important quality aspect of meat. However, a number of studies have shown that a significant portion of retail meat can be considered tough. As a consequence, a significant consumer segment is willing to pay a premium for guaranteed tender meat. However, apart from measuring the shear force, there is no reliable method to predict tenderness. Most of the branded meat programs therefore attempt to ensure eating quality by controlling some of the factors that affect tenderness. Meat tenderness is determined by the amount and solubility of connective tissue, sarcomere shortening during rigor development, and postmortem proteolysis of myofibrillar and myofibrillar-associated proteins. Given the effect of postmortem proteolysis on the Muscle ultrastructure, titin and desmin are likely key substrates that determine meat tenderness. A large number of studies have shown that the calpain proteolytic system plays a central role in postmortem proteolysis and tenderization. In skeletal Muscle, the calpain system consists of at least three proteases, μ-calpain, m-calpain and calpain 3, and an inhibitor of μ- and m-calpain, calpastatin. When activated by calcium, the calpains not only degrade subtrates, but also autolyze, leading to loss of activity. m-Calpain does not autolyze in postmortem Muscle and is therefore not involved in postmortem tenderization. Results from a number of studies, including a study on calpain 3 knockout mice, have shown that calpain 3 is also not involved in postmortem proteolysis. However, a large number of studies, including a study on μ-calpain knockout mice, have shown that μ-calpain is largely, if not solely, responsible for postmortem tenderization. Research efforts in this area should, therefore, focus on elucidation of regulation of μ-calpain activity in postmortem Muscle. Discovering the mechanisms of μ-calpain activity regulation and methods to promote μ-calpain activity should have a dramatic effect on the ability of researchers to develop reliable methods to predict meat tenderness and on the meat industry to produce a consistently tender product.
A. Gorecka - One of the best experts on this subject based on the ideXlab platform.
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Comprehensive Physiology - Biochemistry of the Contractile Proteins of Smooth Muscle
Comprehensive Physiology, 2011Co-Authors: D. J. Hartshorne, A. GoreckaAbstract:The sections in this article are: 1 Background on Contractile Mechanism 1.1 Aspects of Striated Muscle Biochemistry 2 Comparison of Striated and Smooth Muscle Biochemistry 3 Content of Contractile Proteins in Smooth Muscle 4 Actin 5 Tropomyosin 6 Myosin 6.1 Isolation 6.2 Physical Properties and Subunit Composition 6.3 Myosin Fragments 6.4 ATPase Activity 6.5 Ca2+ Binding 6.6 Thick Filament Formation 6.7 Immunochemical Properties 7 Actomyosin 7.1 ATPase Activities 8 Regulation 8.1 Phosphorylation of Myosin 8.2 Phosphatase Activity 8.3 Phosphorylation and the Regulatory Mechanism 8.4 Other Mechanisms 8.5 Role of Tropomyosin in the Regulatory Mechanism 8.6 Summary of the Regulatory Mechanism 8.7 Correlation of Actomyosin ATPase Activity With In Vivo Functioning 9 Other Protein Components 9.1 α-Actinin 9.2 130,000 Component 9.3 100-A Filament Protein
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Biochemistry of the contractile proteins of smooth Muscle
Comprehensive Physiology, 2011Co-Authors: D. J. Hartshorne, A. GoreckaAbstract:The sections in this article are: 1 Background on Contractile Mechanism 1.1 Aspects of Striated Muscle Biochemistry 2 Comparison of Striated and Smooth Muscle Biochemistry 3 Content of Contractile Proteins in Smooth Muscle 4 Actin 5 Tropomyosin 6 Myosin 6.1 Isolation 6.2 Physical Properties and Subunit Composition 6.3 Myosin Fragments 6.4 ATPase Activity 6.5 Ca2+ Binding 6.6 Thick Filament Formation 6.7 Immunochemical Properties 7 Actomyosin 7.1 ATPase Activities 8 Regulation 8.1 Phosphorylation of Myosin 8.2 Phosphatase Activity 8.3 Phosphorylation and the Regulatory Mechanism 8.4 Other Mechanisms 8.5 Role of Tropomyosin in the Regulatory Mechanism 8.6 Summary of the Regulatory Mechanism 8.7 Correlation of Actomyosin ATPase Activity With In Vivo Functioning 9 Other Protein Components 9.1 α-Actinin 9.2 130,000 Component 9.3 100-A Filament Protein
Martin J. Sullivan - One of the best experts on this subject based on the ideXlab platform.
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Exercise intolerance in patients with chronic heart failure
Progress in cardiovascular diseases, 1995Co-Authors: Martin J. Sullivan, Mary H. HawthorneAbstract:Patients with chronic heart failure (CHF) experience significant morbidity because of dyspnea and fatigue with activities of daily living. Although central hemodynamic abnormalities are the hallmark of this disorder, investigators have not shown a relationship between left ventricular ejection fraction or exercise pulmonary capillary wedge pressure and exercise intolerance in this disorder. Recent studies have focused on the contributions of pulmonary abnormalities and alterations in peripheral vasomotor control and skeletal Muscle in exercise intolerance in this disorder. Early anaerobic metabolism occurs in patients with CHF and appears to be caused by a combination of reduced skeletal Muscle blood flow and decreased aerobic enzyme content in skeletal Muscle. Atrophy in skeletal Muscle and alterations in skeletal Muscle fiber typing are accompanied by alterations in contractile function in skeletal Muscle. These results suggest that exercise intolerance in patients with CHF is multifactorial, and that research efforts must consider central hemodynamic abnormalities, pulmonary abnormalities, and alterations in peripheral blood flow and skeletal Muscle Biochemistry and histology. The present review will explore current research in this area and develop a model for understanding exercise intolerance in CHF.
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Altered skeletal Muscle metabolic response to exercise in chronic heart failure. Relation to skeletal Muscle aerobic enzyme activity.
Circulation, 1991Co-Authors: Martin J. Sullivan, Howard J. Green, Frederick R. CobbAbstract:BACKGROUNDExertional fatigue, which frequently limits exercise in patients with chronic heart failure, is associated with early anaerobic metabolism in skeletal Muscle. The present study was designed to examine the skeletal Muscle metabolic response to exercise in this disorder and determine the relation of reduced Muscle blood flow and skeletal Muscle Biochemistry and histology to the early onset of anaerobic metabolism in patients.METHODS AND RESULTSWe evaluated leg blood flow, blood lactate, and skeletal Muscle metabolic responses (by vastus lateralis biopsies) during upright bicycle exercise in 11 patients with chronic heart failure (ejection fraction 21 +/- 8%) and nine normal subjects. In patients compared to normal subjects, peak exercise oxygen consumption was decreased (13.0 +/- 3.3 ml/kg/min versus 30.2 +/- 8.6 ml/kg/min, p less than 0.01), whereas peak respiratory exchange ratio and femoral venous oxygen content were not different (both p greater than 0.25), indicating comparable exercise end p...
