A5090757220- Muscle activation and electromyography studies
- Muscle Physiology and Disorders
- Cardiomyopathy and Myosin Studies
- Neuroscience and Neural Engineering
- Cardiac Structural Anomalies and Repair
- Mechanical Circulatory Support Devices
- Muscle metabolism and nutrition
- Adipose Tissue and Metabolism
- Transcranial Magnetic Stimulation Studies
- Congenital Heart Disease Studies
- Advanced Sensor and Energy Harvesting Materials
- Cardiovascular Effects of Exercise
- Cardiovascular and exercise physiology
- Cardiovascular Function and Risk Factors
- Tissue Engineering and Regenerative Medicine
- Cardiac pacing and defibrillation studies
- Motor Control and Adaptation
- Mitochondrial Function and Pathology
- Nerve Injury and Rehabilitation
- Peripheral Nerve Disorders
- Reconstructive Surgery and Microvascular Techniques
- Exercise and Physiological Responses
- Electrospun Nanofibers in Biomedical Applications
- Children's Physical and Motor Development
- Photoreceptor and optogenetics research
University of Liverpool
2003-2020
British Heart Foundation
1992-2004
Wayne State University
1990-2000
The University of Texas at Austin
1996
The University of Texas Health Science Center at Houston
1995
Washington University in St. Louis
1994
Wythenshawe Hospital
1993
University of Birmingham
1976-1988
Children's Hospital of Philadelphia
1988
Karolinska Institutet
1988
1. The time course of contraction and relaxation in the isometric twitch a rabbit soleus muscle becomes more rapid following tenotomy spinal cord section. This increase speed could be prevented by long‐term electrical stimulation at frequencies 5 or 10/sec. It was not 20 40/sec. 2. Long‐term fast cat muscles frequency 10/sec had slowing effect on relaxation. 3. is concluded that almost continuous low discharge motoneurones innervating postural plays an important part establishing maintaining...
Increased contractile activity of skeletal muscle augments the volume fraction and enzymatic capacity mitochondria suppresses several cytoplasmic enzymes glycolysis. To examine biochemical mechanisms underlying these effects, we measured concentrations cytochrome b mRNA aldolase A in tibialis anterior muscles adult rabbits that had been stimulated via motor nerve to contract continuously at 10 Hz for 5 or 21 days; were compared with corresponding levels unstimulated limbs same animals. After...
Twenty-one enzymes of different metabolic systems were measured in the rabbit fast-twitch tibialis anterior (TA) muscle after electrical stimulation (10 Hz, 24 h/day) for 1 day to 10 wk. Nine analytical methods are either new, (3-oxoacid CoA-transferase, branched-chain-amino-acid aminotransferase, carnitine acetyltransferase, thiolase), improved (glutamate dehydrogenase, glycogen synthase, adenylic acid deaminase), or specially adapted (hexokinase, phosphoglucomutase). The activities (based...
An increase in mitochondrial biogenesis mammalian cells requires a coordinated the expression of number nuclear genes that encode proteins. To examine regulatory mechanisms involved, we used specific anti-sense RNA probes to estimate cellular concentrations mRNA transcripts two such rabbit tibialis anterior muscles subjected vivo 10-21 days indirect electrical stimulation. The unstimulated contralateral muscle same animals provided base line for comparison. Change proteins was assessed terms...
We investigated the restorative potential of intensive electrical stimulation in a patient with long-standing quadriceps denervation. Stimulation started 18 months after injury. After 26 months, thighs were visibly less wasted. Muscle cross-sectional areas, measured by computerized tomography, increased from 36.0 cm2 to 57.9 (right) and 36.1 52.4 (left). Knee torque had become sufficient maintain standing without upper extremity support. Biopsies revealed evidence both growth regeneration...
Fiber type transformation was induced in fast skeletal muscles of the rabbit by chronic electrical stimulation motor nerve. The accompanying changes myosin subunit composition were examined order to establish precise sequence events during this transition. Replacement slow isoforms individual light and heavy chains native did not occur synchronously. resultant stoichiometry different classes are described relation possible mechanisms regulating expression corresponding genes. neonatal form...
Skeletal muscle ventricles (SMVs) were constructed from canine latissimus dorsi and connected to a totally implantable mock circulation device. The SMVs, stimulated by an pulse generator, pumped continuously for up 8 weeks in free-running beagle dogs. Systolic pressures produced the initially of 139 +/- 7.2 mmHg after 1 month continuous pumping 107 7 mmHg, comparable normal physiologic adult beagles (114 21 mmHg). After 2 pumping, mean stroke work SMVs was 0.4 X 10(6) ergs, performance that...
Continuous stimulation of a rabbit fast muscle at 10 Hz changes its physiological and biochemical parameters to those slow muscle. These transformations include the replacement myosin one type by another type. Two hypotheses could explain cellular basis these changes. First, if fibers were permanently programmed be or slow, but not both, change from would involve atrophy fiber accompanied de novo appearance other Alternatively, preexisting changing expression set genes another....
Our understanding of the effects long-term denervation on skeletal muscle is heavily influenced by an extensive literature based rat. We have studied physiological and morphological changes in alternative model, rabbit. In adult rabbits, tibialis anterior muscles were denervated unilaterally selective section motor branches common peroneal nerve examined after 10, 36, or 51 wk. Denervation reduced mass cross-sectional area 50-60% tetanic force 75%, with no apparent reduction specific (force...
Chronic stimulation converts skeletal muscle of mixed fiber type to a uniform made up I, fatigue-resistant fibers. Here, the bioenergetic correlates fatigue resistance in conditioned canine latissimus dorsi are assessed with vivo phosphorus-31 nuclear magnetic resonance (31P-NMR) spectroscopy. After chronic electrical stimulation, five dogs underwent 31P-NMR spectroscopic and isometric tension measurements on contralateral control during for 200, 300, 500, 800 ms an 1,100-ms duty cycle. With...
Single fibers of rabbit fast-twitch tibialis anterior (TA) muscles were analyzed after continuous low-frequency stimulation for up to 8 wk. After 2-5 wk, every fiber showed higher levels citrate synthase, hexokinase, and 3-oxoacid CoA-transferase than any control fiber; in some cases these 2-10 times (well above found even the soleus, a slow-twitch muscle). Average malate dehydrogenase alanine transaminase also rose dramatically, but peak single not much highest controls. These differential...
Implantable electronic stimulators were used to subject fast-twitch tibialis anterior and extensor digitorum longus muscles of adult rabbits a chronically increased level use. Stimulation was discontinued after 6 weeks physiological, histochemical biochemical properties the examined at intervals over ensuing 20 weeks. Previous work had shown that stimulation sufficient bring about substantial transformation type in muscles, which then exhibited much character slow-twitch type. The present...
Glucose transport and phosphorylation are the first steps in utilization of extracellular glucose by skeletal muscle. We have examined relationships between proteins mediating these single fibers identified type dissected from rabbit The level transporter isoform GLUT4, measured immunoblotting, varied among a factor 20 (slow oxidative > fast glycolytic glycolytic). In tibialis anterior muscle, GLUT4 was correlated (r2 = 0.75) with activity malate dehydrogenase, an enzyme representative...
<b>We review here various ways in which cardiac assistance might be derived from a patient9s own skeletal muscle. Calculations based on experimental data and optimistic estimates of the efficiency energy conversions involved suggest that continuous assist available would limited to about 2 litres minute if muscle were used energise an electromechanical device. It more efficient couple mechanically or hydraulically, but these approaches still pose problems anatomical placement, attachment,...