A5051775398- Muscle Physiology and Disorders
- Muscle activation and electromyography studies
- Adipose Tissue and Metabolism
- Cardiomyopathy and Myosin Studies
- Exercise and Physiological Responses
- Ion channel regulation and function
- Mitochondrial Function and Pathology
- Cardiovascular and exercise physiology
- Genetic Neurodegenerative Diseases
- Neuroscience and Neural Engineering
- Sports Performance and Training
- Metabolism and Genetic Disorders
- Ion Channels and Receptors
- Metabolism, Diabetes, and Cancer
- Cardiovascular Effects of Exercise
- Advanced Sensor and Energy Harvesting Materials
- Muscle metabolism and nutrition
- Hormonal and reproductive studies
- Fibromyalgia and Chronic Fatigue Syndrome Research
- Neurobiology and Insect Physiology Research
- Pain Mechanisms and Treatments
- Thyroid Disorders and Treatments
- ATP Synthase and ATPases Research
- Adrenal Hormones and Disorders
- Calcium signaling and nucleotide metabolism
Karolinska Institutet
2014-2024
Carleton University
2013
University of Oslo
2001-2006
Institutt for Eksperimentell Medisinsk Forskning
2001-2006
University College London Hospitals NHS Foundation Trust
1999
University College London
1999
Chinese University of Hong Kong
1988-1996
Royal Astronomical Society
1991
Astronomical Observatory
1991
Weatherford College
1991
Key points Dietary supplementation with inorganic nitrate has beneficial effects on skeletal muscle responses to exercise. Both mitochondrial and extra‐mitochondrial explanations have been proposed. Contractile force of fast‐twitch muscles was enhanced in mice supplemented 1 m NaNO 3 drinking water for 7 days. Myoplasmic free [Ca 2+ ] during tetanic stimulation increased nitrate‐supplemented this accompanied by expression calsequestrin the dihydropyridine receptor. These results provide a...
1. The effect of altered intracellular pH (pHi) on isometric contractions and shortening velocity at 12, 22 32 degrees C was studied in intact, single fibres mouse skeletal muscle. Changes pHi were obtained by exposing to solutions with different CO2 concentrations. 2. Under control conditions (5% CO2), (measured carboxy SNARF‐1) about 0.3 units more alkaline than neutral water each temperature. An acidification 0.5 produced 30% an alkalinization similar size 0% CO2. 3. In acidified tetanic...
Exercise increases glucose transport into skeletal muscle via a pathway that is poorly understood. We investigated the role of endogenously produced reactive oxygen species (ROS) in contraction-mediated transport. Repeated contractions increased 2-deoxyglucose (2-DG) uptake roughly threefold isolated, mouse extensor digitorum longus (fast-twitch) muscle. N-Acetylcysteine (NAC), non-specific antioxidant, inhibited 2-DG by approximately 50% (P < 0.05 versus control values), but did not...
Significance High-intensity interval training (HIIT) has become popular because it is a time-efficient way to increase endurance. An intriguing and so-far-unanswered question how few minutes of HIIT can be that effective. We exposed recreationally active men one session three six sets 30-s high-intensity cycling exercise. Muscle biopsies taken 24 h later showed an extensive fragmentation the sarcoplasmic reticulum (SR) Ca 2+ channels, ryanodine receptor 1 (RyR1). In isolated mouse muscle...
Hepatic tryptophan pyrrolase and its circulating substrate, whole blood tryptophan, have a circadian rhythmicity in mice. Intact adrenocortical function is required for the normal of both enzyme substrate although an altered but less apparent rhythm persists adrenalectomized state.
Skeletal muscle often shows a delayed force recovery after fatiguing stimulation, especially at low stimulation frequencies. In this study we focus on the role of reactive oxygen species (ROS) in fatigue‐induced prolonged low‐frequency depression. Intact, single fibres were dissected from flexor digitorum brevis (FDB) muscles rats and wild‐type superoxide dismutase 2 (SOD2) overexpressing mice. Force myoplasmic free [Ca 2+ ] ([Ca i ) measured. Fibres stimulated different frequencies before...
Obesity and insulin resistance are associated with enhanced fatty acid utilization, which may play a central role in diabetic cardiomyopathy. We now assess the effect of saturated palmitate (1.2 mmol/l) on Ca(2+) handling, cell shortening, mitochondrial production reactive oxygen species (ROS) freshly isolated ventricular cardiomyocytes from normal (wild-type) obese, insulin-resistant ob/ob mice. Cardiomyocytes were electrically stimulated at 1 Hz, signal fluorescent indicators was measured...
Cancer patients receiving doxorubicin chemotherapy experience both muscle weakness and fatigue. One postulated mediator of the dysfunction is an increase in tumor necrosis factor-α (TNF), a proinflammatory cytokine that mediates limb contractile through TNF receptor subtype 1 (TNFR1). Our main hypothesis was systemic administration would cause Systemic (20 mg/kg) depressed maximal force extensor digitorum longus (EDL; P < 0.01), accelerated EDL fatigue ( elevated serum levels 0.05) 72 h...
<h3>Objectives</h3> Polymyositis and dermatomyositis are characterised by muscle weakness fatigue even in patients with normal histology via unresolved pathogenic mechanisms. In this study, we investigated the mechanisms which high mobility group box protein 1 (HMGB1) acts to accelerate development. <h3>Methods</h3> Intact single fibres were dissociated from flexor digitorum brevis (FDB) of wild type, receptor for advanced glycation endproduct (RAGE) knockout toll like 4 (TLR4) mice cultured...
The contractile performance of skeletal muscle declines during intense activities, i.e. fatigue develops. Fatigued can enter a state prolonged low-frequency force depression (PLFFD). PLFFD be due to decreased tetanic free cytosolic [Ca(2+) ] ([Ca(2+) ]i ) and/or myofibrillar Ca(2+) sensitivity. Increases in reactive oxygen and nitrogen species (ROS/RNS) may contribute fatigue-induced reductions. We studied whether pharmacological ROS/RNS inhibition delays counteracts the development PLFFD....
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTThe Vapor Phase Dissociation of Some Carboxylic Acids. II. Formic and Propionic Acids1,2Moddie D. Taylor Joseph BrutonCite this: J. Am. Chem. Soc. 1952, 74, 16, 4151–4152Publication Date (Print):August 1, 1952Publication History Published online1 May 2002Published inissue 1 August 1952https://pubs.acs.org/doi/10.1021/ja01136a057https://doi.org/10.1021/ja01136a057research-articleACS PublicationsRequest reuse permissionsArticle...
Isolated whole skeletal muscles fatigue more rapidly than isolated single muscle fibres. We have now employed this difference to study mechanisms of fatigue. soleus and extensor digitorum longus (EDL) were fatigued by repeated tetanic stimulation while measuring force production. Neither application 10 m lactic acid nor increasing the [K + ] bath solution from 5 had any significant effect on rate decline during induced brief tetani. Soleus slightly faster continuous in ]. Inhibition...
The involvement of Ca(2+) in insulin-mediated glucose uptake is uncertain. We measured influx (as Mn(2+) quenching or Ba(2+) influx) and 2-deoxyglucose (2-DG) single muscle fibers isolated from limbs adult mice; 2-DG was also whole muscles. Exposure to insulin increased the cells. presence decreased by 2-aminoethoxydiphenyl borate (2-APB) membrane-permeable diacylglycerol analog 1-oleyl-2-acetyl-sn-glycerol (OAG), agents frequently used block activate, respectively, nonselective cation...
Mammals exposed to a cold environment initially generate heat by repetitive muscle activity (shivering). Shivering is successively replaced the recruitment of uncoupling protein-1 (UCP1)-dependent production in brown adipose tissue. Interestingly, adaptations observed skeletal muscles cold-exposed animals are similar those with endurance training. We hypothesized that increased myoplasmic free [Ca2+] ([Ca2+]i) important for these adaptations. To test this hypothesis, experiments were...
Idiopathic inflammatory myopathies (IIMs) are heterogeneous rheumatic disorders of unknown cause characterized by muscle weakness, cell infiltrates, and major histocompatibility complex (MHC) class I expression on fibers. The nonhistone nuclear protein alarmin high-mobility group box 1 (HMGB1) has been detected extranuclearly in biopsies from patients with IIMs. We hypothesize that HMGB1 a central role the particularly early phases Experiments were performed skeletal fibers isolated adult...
Genetic mutations that affect mitochondrial function often cause skeletal muscle dysfunction. Here, we used mice with skeletal-muscle-specific disruption of the nuclear gene for transcription factor A ( Tfam ) to study whether changes in cellular Ca 2+ handling is part mechanism dysfunction myopathy. Force measurements were combined cytosolic , and membrane potential reactive oxygen species intact, adult fibres. The results show reduced sarcoplasmic reticulum (SR) storage capacity KO muscles...
This study aimed to identify a mechanism for statin-induced myopathy that explains its prevalence and selectivity skeletal muscle, understand interaction with moderate exercise. Statin-associated adverse muscle symptoms reduce adherence statin therapy; this limits the effectiveness of statins in reducing cardiovascular risk. The issue is further compounded by perceived interactions between treatment examined muscles from individuals taking rats treated 4 weeks. In caused dissociation...