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Journal of Anatomy Jun 1996Morphological features and the chronology of muscle changes after denervation were studied over a 21 d period in 2 heavy (HW) and light-weight (LW) strains of 6-wk-old... (Comparative Study)
Comparative Study
Morphological features and the chronology of muscle changes after denervation were studied over a 21 d period in 2 heavy (HW) and light-weight (LW) strains of 6-wk-old male turkeys. The atrophy of tibialis cranialis, gastrocnemius lateralis and plantaris muscles was apparent at d 3 after denervation. By d 21 the weight of these muscles had reached 45-60% of that of nondenervated contralateral muscle. Cellular lesions, such as irregularities in mitochondrial distribution or coagulative necrosis with fragmentation and lysis associated with moderate infiltration of inflammatory cells, were similar in both strains. Ten days after denervation, immunolabelling of a proliferating cell nuclear antigen (PCNA) expressed during the G1 and S phase of the cell cycle revealed satellite cell activation in denervated muscles. The number of satellite cells activated at d 21 was markedly greater in the HW than LW strain. Morphometric analysis revealed that fast twitch (type II) fibres were atrophied after denervation, whereas slow-twitch (type I) and slow tonic (type III) fibres were hypertrophied from d 10. Hypertrophy occurred more rapidly in the LW than HW strain.
Topics: Animals; Body Weight; Hypertrophy; Immunohistochemistry; Inflammation; Male; Muscle Denervation; Muscle Fibers, Fast-Twitch; Muscle Fibers, Slow-Twitch; Muscle, Skeletal; Proliferating Cell Nuclear Antigen; Time Factors; Turkeys
PubMed: 8763485
DOI: No ID Found -
The Journal of Biological Chemistry Nov 2009Nebulin is a giant filamentous F-actin-binding protein ( approximately 800 kDa) that binds along the thin filament of the skeletal muscle sarcomere. Nebulin is one of...
Nebulin is a giant filamentous F-actin-binding protein ( approximately 800 kDa) that binds along the thin filament of the skeletal muscle sarcomere. Nebulin is one of the least well understood major muscle proteins. Although nebulin is usually viewed as a structural protein, here we investigated whether nebulin plays a role in muscle contraction by using skinned muscle fiber bundles from a nebulin knock-out (NEB KO) mouse model. We measured force-pCa (-log[Ca(2+)]) and force-ATPase relations, as well as the rate of tension re-development (k(tr)) in tibialis cranialis muscle fibers. To rule out any alterations in troponin (Tn) isoform expression and/or status of Tn phosphorylation, we studied fiber bundles that had been reconstituted with bacterially expressed fast skeletal muscle recombinant Tn. We also performed a detailed analysis of myosin heavy chain, myosin light chain, and myosin light chain 2 phosphorylation, which showed no significant differences between wild type and NEB KO. Our mechanical studies revealed that NEB KO fibers had increased tension cost (5.9 versus 4.4 pmol millinewtons(-1) mm(-1) s(-1)) and reductions in k(tr) (4.7 versus 7.3 s(-1)), calcium sensitivity (pCa(50) 5.74 versus 5.90), and cooperativity of activation (n(H) 3.64 versus 4.38). Our findings indicate the following: 1) in skeletal muscle nebulin increases thin filament activation, and 2) through altering cross-bridge cycling kinetics, nebulin increases force and efficiency of contraction. These novel properties of nebulin add a new level of understanding of skeletal muscle function and provide a mechanism for the severe muscle weakness in patients with nebulin-based nemaline myopathy.
Topics: Animals; Calcium; Kinetics; Mice; Mice, Knockout; Muscle Contraction; Muscle Fibers, Skeletal; Muscle Proteins; Muscle Tonus; Sarcomeres
PubMed: 19736309
DOI: 10.1074/jbc.M109.049718 -
Journal of Biomedical Optics Apr 2016We highlight the options available for noninvasive optical diagnostics of reporter gene expression in mouse tibialis cranialis muscle. An in vivo multispectral imaging...
We highlight the options available for noninvasive optical diagnostics of reporter gene expression in mouse tibialis cranialis muscle. An in vivo multispectral imaging technique combined with fluorescence spectroscopy point measurements has been used for the transcutaneous detection of enhanced green fluorescent protein (EGFP) expression, providing information on location and duration of EGFP expression and allowing quantification of EGFP expression levels. For EGFP coding plasmid (pEGFP-Nuc Vector, 10 μg/50 ml 10 μg/50 ml ) transfection, we used electroporation or ultrasound enhanced microbubble cavitation [sonoporation (SP)]. The transcutaneous EGFP fluorescence in live mice was monitored over a period of one year using the described parameters: area of EGFP positive fibers, integral intensity, and mean intensity of EGFP fluorescence. The most efficient transfection of EGFP coding plasmid was achieved, when one high voltage and four low voltage electric pulses were applied. This protocol resulted in the highest short-term and long-term EGFP expression. Other electric pulse protocols as well as SP resulted in lower fluorescence intensities of EGFP in the transfected area. We conclude that noninvasive multispectral imaging technique combined with fluorescence spectroscopy point measurements is a suitable method to estimate the dynamics and efficiency of reporter gene transfection in vivo.
Topics: Animals; Electroporation; Equipment Design; Female; Green Fluorescent Proteins; Histocytochemistry; Male; Mice; Mice, Inbred C57BL; Muscle, Skeletal; Optical Imaging; Sonication; Transfection
PubMed: 27129126
DOI: 10.1117/1.JBO.21.4.045003 -
Journal of the American Veterinary... Jul 2002To evaluate use of transcranial magnetic motor evoked potentials for assessment of the functional integrity of the cervical spinal cord in large-breed dogs with cervical... (Clinical Trial)
Clinical Trial Randomized Controlled Trial
OBJECTIVE
To evaluate use of transcranial magnetic motor evoked potentials for assessment of the functional integrity of the cervical spinal cord in large-breed dogs with cervical spinal cord disease.
DESIGN
Randomized, controlled, masked study.
ANIMALS
10 healthy large-breed control dogs and 25 large-breed dogs with cervical spinal cord diseases.
PROCEDURE
Affected dogs were allocated to 3 groups on the basis of neurologic status: signs of neck pain alone, ambulatory with ataxia in all limbs, or nonambulatory. Transcranial magnetic stimulation was performed on each dog with the same standard technique. Motor evoked potentials (MEP) were recorded from electrodes inserted in the tibialis cranialis muscle. Following the procedure, each dog was anesthetized and cervical radiography, CSF analysis, and cervical myelography were performed. The MEP latencies and amplitudes were correlated with neurologic status of the dogs after correction for neuronal path length.
RESULTS
Mean MEP latencies and amplitudes were significantly different between control dogs and dogs in each of the 3 neurologic categories, but were not significantly different among dogs in the 3 neurologic categories. A linear association was evident between MEP latencies and amplitudes and severity of neurologic deficits; the more severe the neurologic deficits, the more prolonged the latencies and the more decreased the amplitudes.
CONCLUSIONS AND CLINICAL RELEVANCE
Transcranial magnetic MEP are useful to assess severity of cervical spinal cord disease in large-breed dogs. Impairment of the functional integrity of the cervical spinal cord was found even in dogs with neck pain alone.
Topics: Animals; Ataxia; Cervical Vertebrae; Dog Diseases; Dogs; Electric Stimulation; Electromagnetic Fields; Electromyography; Evoked Potentials, Motor; Female; Male; Neck Muscles; Neurologic Examination; Severity of Illness Index; Spinal Cord Diseases
PubMed: 12420825
DOI: 10.2460/javma.2002.221.60 -
Medical & Biological Engineering &... Jul 2010The aim of this study was to theoretically and experimentally investigate electroporation of mouse tibialis cranialis and to determine the reversible electroporation...
The aim of this study was to theoretically and experimentally investigate electroporation of mouse tibialis cranialis and to determine the reversible electroporation threshold values needed for parallel and perpendicular orientation of the applied electric field with respect to the muscle fibers. Our study was based on local electric field calculated with three-dimensional realistic numerical models, that we built, and in vivo visualization of electroporated muscle tissue. We established that electroporation of muscle cells in tissue depends on the orientation of the applied electric field; the local electric field threshold values were determined (pulse parameters: 8 x 100 micros, 1 Hz) to be 80 V/cm and 200 V/cm for parallel and perpendicular orientation, respectively. Our results could be useful electric field parameters in the control of skeletal muscle electroporation, which can be used in treatment planning of electroporation based therapies such as gene therapy, genetic vaccination, and electrochemotherapy.
Topics: Algorithms; Animals; Anisotropy; Electromagnetic Fields; Electroporation; Female; Magnetic Resonance Imaging; Mice; Mice, Inbred C57BL; Models, Biological; Muscle Fibers, Skeletal; Muscle, Skeletal
PubMed: 20424926
DOI: 10.1007/s11517-010-0614-1 -
American Journal of Physiology.... Apr 2007A key regulatory point in the control of fatty acid (FA) oxidation is thought to be transport of FAs across the mitochondrial membrane by carnitine palmitoyltransferase...
A key regulatory point in the control of fatty acid (FA) oxidation is thought to be transport of FAs across the mitochondrial membrane by carnitine palmitoyltransferase I (CPT I). To investigate the role of CPT I in FA metabolism, we used in vivo electrotransfer (IVE) to locally overexpress CPT I in muscle of rodents. A vector expressing the human muscle isoform of CPT I was electrotransferred into the right lateral muscles of the distal hindlimb [tibialis cranialis (TC) and extensor digitorum longus (EDL)] of rats, and a control vector expressing GFP was electrotransferred into the left muscles. Initial studies showed that CPT I protein expression peaked 7 days after IVE (+104%, P<0.01). This was associated with an increase in maximal CPT I activity (+30%, P < 0.001) and a similar increase in palmitoyl-CoA oxidation (+24%; P<0.001) in isolated mitochondria from the TC. Importantly, oxidation of the medium-chain FA octanoyl-CoA and CPT I sensitivity to inhibition by malonyl-CoA were not altered by CPT I overexpression. FA oxidation in isolated EDL muscle strips was increased with CPT I overexpression (+28%, P<0.01), whereas FA incorporation into the muscle triacylglycerol (TAG) pool was reduced (-17%, P<0.01). As a result, intramyocellular TAG content was decreased with CPT I overexpression in both the TC (-25%, P<0.05) and the EDL (-45%, P<0.05). These studies demonstrate that acute overexpression of CPT I in muscle leads to a repartitioning of FAs away from esterification and toward oxidation and highlight the importance of CPT I in regulating muscle FA metabolism.
Topics: Animals; Biomarkers; Carnitine O-Palmitoyltransferase; Electroporation; Esterification; Fatty Acids; Hindlimb; Humans; In Vitro Techniques; Lipid Metabolism; Male; Mitochondria, Muscle; Muscle, Skeletal; Oxidation-Reduction; Palmitates; Palmitoyl Coenzyme A; Rats; Rats, Wistar; Transfection; Triglycerides
PubMed: 17179390
DOI: 10.1152/ajpendo.00561.2006