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At least 1,207 records · Page 67Linked to original sources
PubMed1991

A method for preparing skeletal muscle fiber basal laminae.

Previous attempts to prepare skeletal muscle basal laminae (BL) for ultrastructural analyses have been hampered by difficulties in successfully removing skeletal muscle proteins and cellular debris from BL tubes. In the present study we describe a two phase method which results in an acellular muscle preparation, the BL of which are examined by light, transmission electron, and scanning electron microscopy. In the first phase, excised rat extensor digitorum longus muscles are subjected to x-radiation and then soaked in Marcaine to inhibit muscle regeneration and to destroy peripheral muscle fibers. The muscles are then grafted back into their original sites and allowed to remain in place 7-14 days to allow for maximal removal of degenerating muscle tissue with minimal scar tissue formation. In the second phase, the muscle grafts are subjected sequentially to EDTA, triton X-100, DNAase, and sodium deoxycholate to remove phagocytizing cells and associated degenerating muscle tissue. These procedures result in translucent, acellular muscle grafts which show numerous empty tubes of BL backed by endomysial collagenous fibers. These preparations should be useful for morphological analyses of isolated muscle BL and for possible in vitro studies by which the biological activity of muscle BL can be examined.

Animals↗
PubMed1998

Potent stimulation of myofilament force and ATPase activity of skeletal muscle by eudistomin M, a novel Ca(++)-sensitizing agent from a Caribbean tunicate.

In the course of our survey of biologically active compounds from natural sources, eudistomins were isolated from a Caribbean tunicate Eudistoma olivaceum. In the present experiments, eudistomin M (Eud-M, > 10(-5) M) caused a concentration-dependent increase in the contractile response of skinned fibers from guinea pig skeletal psoas muscles to Ca++. The superprecipitation and ATPase activity of myosin B from fast skeletal muscles of rabbit back and leg were potentiated by this compound (> 10(-5) M) in a concentration-dependent manner. In skinned fibers, superprecipitation and the ATPase activity of myosin B, Eud-M shifted the concentration-response curve for Ca++ to the upper direction. Ca(++)-, K(+)-EDTA- or Mg(++)-ATPase was not affected by Eud-M. This compound had no effect on the ATPase activity of actomyosin reconstituted from actin and myosin in the presence or absence of troponin. However, the ATPase activity of actin-myosin-troponin-tropomyosin reconstituted system was increased significantly by Eud-M. These results suggest that Eud-M increases the Ca++ sensitivity of the contractile apparatus in skeletal muscles at least partially mediated through troponin-tropomyosin system and thus enhances the ATPase activity of myosin B and the contractile force of myofilament.

Actin Cytoskeleton↗
PubMed1984

Electromyography of the paravertebral muscles in idiopathic scoliosis. Measurements of amplitude and spectral changes under load.

The myoelectric activity of the paraspinal muscles was recorded in girls with idiopathic scoliosis and in healthy controls. The muscles of the back were loaded isometrically and the signals recorded at the T8 and L3 levels were analysed as regards amplitude and frequency. A comparatively higher signal amplitude was found on the convex side of the scoliosis curve. This was found to be due to a lower amplitude on the concave side when the scoliosis group was compared to the controls. The amplitude difference was correlated to the degree of scoliosis. A shift in the myoelectric spectrum toward lower frequencies occurred during the loading period. There were no differences in this respect between the sides of the scoliosis, nor were there differences between the scoliosis patients and the controls. Secondary adaptation to the higher load demand by the muscles on the convex side in scoliosis is the most probable explanation for our observations.

Adolescent↗
PubMed2006

[Gymnastic school sport injuries--aspects of preventive measures].

INTRODUCTION: Gymnastic school sport injuries account for a significant morbidity and mortality among children and adolescents. Preventive issues may be derived from a thorough in-depth analysis of the pattern and circumstances of gymnastic injuries. METHODS: During a school year among 3993 schools in 43 889 classes with 993 056 pupils 2234 school sport injuries have been reported to the Gemeinde Unfall Versicherung (GUV) Niedersachsen, Germany. RESULTS: Gymnastic sport injuries account for 18 % (403 accidents), which is second after ball sports injuries. Regarding the distribution of the gymnastic disciplines, vault was the major discipline with 34 %, followed by floor exercise (21.3 %), mini- and competition trampoline (16.8 %), and parallel bars (8.2 %). The analysis of the type of injury during vault accidents revealed contusion (31 %) as the predominant injury, followed by sprains (15.4 %), and fractures (15.4 %). Floor exercise injuries distributed among distorsions (26.7 %), contusions (18.6 %), muscle tears (14 %). Back injuries especially of the cervical and thoracic spine, accounted for 40 % of all their injuries. Minor head injuries account for 4.7 % of all floor exercise injuries. Mini-trampoline injuries distribute among contusions (30 %), fractures (22.5 %), distorsions (7.5 %). 21.8 % collisions were noted against a box in comparison to 6.8 % in case of the horse. CONCLUSION: Gymnast injuries account for a significant number of all school sport related injuries. Vault and floor exercise account for the vast majority of all injuries, with alarming high numbers of spine injuries during floor exercise and mini-trampoline. A preservation of a high level of attention during a sport lesson, safety measures including appropriate mats and landing zones are mandatory to reduce injuries. Muscle injuries and ankle sprains can be prevented by a prospective proprioceptive training intervention to be implemented in school sports.

Adolescent↗
PubMed1983

Encephalopathic effect of phenol in rats.

The coma-inducing effect of phenol was studied in normal 300 +/- 50 gm Sprague-Dawley rats. Dose-response curves were developed which showed that one-half the animals became deeply comatose with 540 mumol of intraperitoneal phenol and 100% with 600 mumol. Five stages of encephalopathy were readily distinguished. In stage I, spontaneous activity was noticeably decreased, posture was upright, back-leg control normal, muscle tonus slightly increased, and response to stimuli normal. In Stage V, activity was gone, the rats were deeply unconscious, righting reflex and back-leg control were gone, muscles were completely relaxed, and there was no response to stimuli. With a coma-inducing dose of phenol, spontaneous activity decreased. After 1 min a body tremor developed interspersed with unpredictable jumping, and all four limbs began to shake. Leg control and then the righting reflex were lost by 2 min. Within 5 min rats were deeply unconscious and muscles completely relaxed while shaking of limbs continued until recovery 20 to 60 min later or death. With 480 mumol or less, none of the rats became comatose, but the shaking of limbs was present. The coma-inducing dose of phenol was reduced by 10% to 20% with simultaneous injection of subcoma doses of NH4+ or OA and by 20% to 30% with simultaneous DMDS leads to 2 methanethiol. Conversely, a subcoma dose of phenol reduced the coma-inducing doses of NH4+, OA, and DMDS by approximately 20% to 25%. Thus phenol, which accumulates in human hepatic failure, induces coma by itself in rats and acts synergistically with other hepatic failure toxins.

Animals↗
PubMed1989

Doppler ultrasound velocity mapping of extra-ocular muscles: a preliminary report.

Colour doppler imaging and conventional spectral doppler/B-mode techniques were used to detect and quantify rectus muscle movement during voluntary saccades. A velocity gradient was evident in all muscles studied--low velocities near the muscle origin at the back of the orbit increasing linearly to a maximum near the muscle insertion on the globe. A consistent reduction in velocity occurred along muscles injected with botulinum toxin. Doppler ultrasound complements current clinical eye movement recording techniques--electronystagmography, infrared light reflection methods and magnetic induction methods--insofar as it detects movement in parts of the muscle itself rather than movement of the globe secondary to muscle contraction. Future developments in colour doppler imaging will make the technique clinically more applicable.

Botulinum Toxins↗
PubMed1995

Inactivation of Myf-6 and Myf-5 genes in mice leads to alterations in skeletal muscle development.

Myf-6, alternatively called MRF4 or herculin, is a member of a group of muscle-specific transcription factors which also comprises Myf-5, myogenin and MyoD. All family members show distinct expression patterns during skeletal muscle development and can convert a variety of cell lines to myocytes. We disrupted the Myf-6 gene in mice to investigate its functional role in the network of regulatory factors controlling myogenesis. Homozygous mice carrying the disrupted Myf-6 gene show pronounced down-regulation of Myf-5 transcription for reasons presently unknown. Consequently, these mice represent a double knock-out model for Myf-6 and Myf-5. The mutants resemble most of the Myf-5 phenotype with aberrant and delayed early myotome formation and lack of distal rib structures. In addition, we find a reduction in the size of axial muscles in the back. Apart from changes in the pattern of some contractile protein isoforms, the existing myofibers appear fairly normal. This suggests that Myf-6 has no major role in the maturation of myotubes, as previously proposed. Our results provide evidence that skeletal myogenesis can proceed in the absence of two myogenic factors, Myf-5 and Myf-6, therefore they must exert largely non-redundant functions in vivo.

Animals↗
PubMed2006

[Percutaneous dorsal versus open instrumentation for fractures of the thoracolumbar border. A comparative, prospective study].

STUDY DESIGN: A prospective clinical study. OBJECTIVE: To evaluate whether a percutaneous dorsal instrumentation of thoracolumbar fractures prevents irreversible damage to the spinal muscles. METHODS: A total of 57 patients with thoracolumbar fractures (Th12-L4) were divided into two groups, comparable in terms of gender, fracture level, classification and surgical concept. In the first, 24/57 patients were treated using an open procedure (OP-G); in the second, 33/57 were treated via percutaneous dorsal instrumentation (PER-G). Fracture localisation and classification, accuracy of pedicle screw placement, perioperative blood loss, OR- and image converter time as well as muscle damage (needle-EMG) were evaluated. RESULTS: OR- and image converter time as well as the accuracy of pedicle screw placement were not statistically different between groups. The difference in perioperative blood loss [43 (10-90) ml (PER-G) vs [870 (570-1,200 ml (OP-G)] was statistically significant (P <0.005). Needle EMG revealed no muscle damage, and the physiological activity and muscle potentials were normal (PER-G). In the OP-G, polyphasic EMG signals were most common (80%), a sign of the drop-out of numerous motor units. CONCLUSIONS: The open procedure caused permanent and significant damage to the strongest extensors of the autochthonus back musculature, the m. multifidus, which results from multisegment combined damage to the r. posterior nervi spinalis and muscle fibres. In contrast, percutaneous placement of an internal fixative reduces perioperative access morbidity causing little iatrogenic damage to back muscles and only a minor perioperative blood loss.

Adult↗
PubMed2004

Electrical twitch-obtaining intramuscular stimulation in lower back pain: a pilot study.

OBJECTIVES: To determine if electrical twitch-obtaining intramuscular stimulation (ETOIMS) provides greater myofascial lower back pain relief than muscle stimulation or skin stimulation. DESIGN: In this single-blinded, crossover, pilot trial performed at a university-affiliated outpatient rehabilitation medicine department in Taiwan, 12 acupuncture-naive patients with lower back pain of 3-60 mos duration received one crossover treatment every 2 wks by monopolar needle electrode insertion at bilateral T10-S1 levels to: (1) paraspinal muscles, (2) overlying skin, and (3) paraspinal muscles with ETOIMS applied via the needle electrode at individual treatment sites. A total of 30 manual insertions per side per treatment were performed, with withdrawal after 2 secs. Beginning 1 wk before each trial and continuing until 2 wks after, patients completed a visual analog scale twice daily. In addition, on the day of treatment, patients received a physical examination and completed a visual analog scale both before and after treatment. RESULTS: Significant and immediate reduction in the visual analog scale levels was noted only with ETOIMS. Immediate improvement occurred in one of nine physical tests with muscle stimulation and ETOIMS only. In the 2 wks after treatment, absolute visual analog scale levels for ETOIMS were significantly lower than muscle stimulation and skin stimulation. ETOIMS resulted in a greater percentage of pain relief in the first week after treatment, although it was not statistically significant from muscle stimulation and skin stimulation. CONCLUSIONS: ETOIMS provided significantly greater immediate and sustained myofascial lower back pain relief than muscle stimulation and skin stimulation. Although a greater percentage of pain reduction occurred with ETOIMS, it was not statistically significant.

Acupuncture Therapy↗
PubMedDate not supplied

Evaluation of mitomycin to limit postoperative adhesions in strabismus surgery.

BACKGROUND: Ocular motility dysfunction following strabismus surgery may be the result of postoperative scarring or the formation of adhesions. Mitomycin C (MMC) has been used with encouraging results as an adjunct to standard treatment of hypertrophic conjunctival scars after strabismus surgery. It has been demonstrated that MMC does not inhibit muscle reattachment and might inhibit adhesions and scar formation in the rabbit. We investigated in a rabbit model effectiveness of MMC in reducing the formation of postoperative adhesions following reoperations and the tensile strength of the new musculo-scleral junction. METHODS: A prospective, masked-observer, controlled study was performed in rabbits. Symmetrical bilateral recessions of the superior and inferior rectus muscles were performed on each rabbit. A reoperation was performed 6 weeks later, in which the muscles were advanced back to their original insertion. During the reoperation, one eye served as the control while the other was treated with a 5-minute intraoperative exposure to topical mitomycin. RESULTS: Mitomycin reduced the formation of adhesions and the amount of postoperative scarring. The tensile strength of the musculo-scleral junction was reduced in the mitomycin-treated eyes but exceeded the force generated during extraocular ductions. CONCLUSION: MMC may be an effective adjunctive therapy in the treatment of strabismus associated with pre-existing adhesions or scarring.

Animals↗
PubMed1992

Dying back type axonal degeneration of sensory nerve terminals in muscle spindles of the gracile axonal dystrophy (GAD) mutant mouse.

A disorder of the gracile axonal dystrophy (GAD) mutant mouse is characterized by a neuromuscular disease with sensory ataxia (detectable 30 days after birth) and paresis of the hindlimbs (detectable at 80 days). In the sensory ataxia stage, histological study of the primary sensory system shows that, in addition to the lesions in the central nervous system, peripherally projecting axons have also started to degenerate at their distal ends in muscle spindles. Although the structure of Ia fibre endings appear normal until 15 days after birth, initial changes in the annulo-spiral structure are detected around the 20th day by a degeneration of the terminal axons. Degeneration then progressed proximally and the secondary endings also start to degenerate. Neuron cell bodies located in the dorsal root ganglia are morphologically intact until the later stages. Chronological studies indicate that, although axonal degeneration progresses throughout life, it is accentuated during the rapid somatic growth period. Around 50 days of age, transient regeneration takes place at axonal endings when somatic growth has attained a plateau. Such primary sensory endings tend to be restored by fine, multiple axons which gain access to the intrafusal fibres through the original endoneurial tubes. Ultrastructural observations at the fully affected stage show intrafusal muscle fibres lying scattered within spindles due to loss of the fine network of inner capsule layers and an almost complete loss of sensory endings from the surface of intrafusal muscle fibres. These results indicate that this mutant mouse is a useful model for naturally occurring 'dying back' type axonal degeneration or 'central and peripheral distal axonopathies', and would provide significant information about the complete evolution of the pathological processes involved.

Animals↗
PubMed2004

Engineering novel spinal circuits to promote recovery after spinal injury.

We have developed an innovative way to establish a functional bridge around a spinal lesion. We disconnected the T13 nerve from its muscle targets, leaving the proximal end intact. The cut end was inserted either into an intact spinal cord, to assess regeneration of T13 axons into the cord and synapse formation with spinal neurons, or caudal to a hemisection at L2/3, to assess restoration of function below the injury. Four to 28 weeks later, anterograde tracers indicated that axons from the inserted T13 nerve regenerated into the ventral horn, the intermediate zone, and dorsal horn base, both in intact and hemisected animals. Antibodies to cholinergic markers showed that many regenerating axons were from T13 motoneurons. Electrical stimulation of the T13 nerve proximal to the insertion site 4 weeks or more after insertion into the intact cord evoked local field potentials in the intermediate zone and ventral horn, which is where T13 axons terminated. Stimulation of T13 in 71% of the animals (8 hemisected, 7 intact) evoked contraction of the back or leg muscles, depending on the level of insertion. Animals in which T13 was inserted caudal to hemisection had significantly less spasticity and muscle wasting and greater mobility at the hip, knee, ankle, and digits in the ipsilateral hindlimb than did animals with a hemisection only. Thus, T13 motor axons form novel synapses with lumbosacral motor circuits. Because the T13 motor neurons retain their connections to the brain, these novel circuits might restore voluntary control to muscles paralyzed below a spinal lesion.

Animals↗
PubMed1999

[Horizontal deceleration trauma with diffuse decollement bleeding--a casuistry].

Treatment of severe haemorrhage caused by multiple trauma is a serious challenge to preclinical as well as clinical management. This is a case report of a motorcycle accident in which a patient sustained total amputation of both legs. Following adequate preclinical care, vital indication led to the patient's immediate surgical treatment. After initially successful haemodynamic stabilisation, the patient developed a horizontal deceleration trauma which resulted in an extended decollement of the muscles of the back and buttock. During the further clinical course, soft tissue bleeding occurred that affected the whole torso. Due to its extent, the bleeding could not be treated surgically, nor did it allow of haemodynamic stabilisation despite continuous massive transfusion. Retrospectively, the impressing amputation injury was treated successfully. In spite of all available surgical and intensive care efforts, however, the slowly demasking monstrous decollement with diffuse tissue bleeding proved to be an injury pattern leading to the patient's death.

Accidents, Traffic↗
PubMed2003

Preventing nursing back injuries: redesigning patient handling tasks.

The researchers identified nine patient handling tasks that place nursing staff at high risk for musculoskeletal injuries. An expert panel redesigned these tasks using new patient handling technologies and work practice controls. The key objective was to evaluate the biomechanical benefit of the redesigned tasks. Back and shoulder muscle activity, forces on the lumbar spine, shoulder joint moments, and perceived comfort were evaluated in a laboratory setting. Using objective and subjective data, 63 participants who performed the redesigned tasks were compared with 71 participants who used standard procedures. Objective data revealed significant improvement in five of the redesigned tasks, while staff subjectively rated four of the redesigned tasks as significantly improved. Nursing tasks can be redesigned to improve caregiver and patient safety using new patient handling technologies and work practice controls. Further study is needed to redesign other high risk tasks to promote safer work environments.

Back Injuries↗
PubMed1998

Pharmacologic therapies.

Medical treatment of low back pain is at best palliative. While no drugs are specifically labeled for back pain treatment, analgesics, muscle relaxants, and corticosteroids are used in practice to augment rest and exercise programs. Invasive therapy remains contentious. This article reviews the available literature on the various pharmacologic therapies. In addition, newly postulated outcome measures for future back pain studies are discussed.

Acute Disease↗
PubMed2004

Paraspinal muscles and intervertebral dysfunction: part one.

BACKGROUND: One of the diagnostic characteristics of the manipulable spinal lesion--a musculoskeletal disturbance detected by manual palpation and corrected with manipulation--is said to be altered segmental tissue texture. Various manual therapy authors have speculated on the possible nature of this tissue change, with some authors hypothesizing that it represents deep segmental muscle overactivity. OBJECTIVES: To review the literature relating to the detection and nature of altered paraspinal tissue texture, proposed explanations for altered tissue texture, evidence for the plausibility of paraspinal muscle spasm, and evidence of muscle dysfunction associated with low back pain (LBP). DATA SOURCE: MEDLINE and CINAHL databases were searched using various combinations of the keywords paraspinal, muscle, palpation, EMG, spine, low back pain, pain, myofascial, hardness, manipulation, reliability, and somatic dysfunction, along with searching the bibliographies of selected articles and textbooks. DATA EXTRACTION: All relevant data were used. RESULTS: Little direct evidence exists for the nature of abnormal paraspinal tissue texture detected by palpation. Palpation for tenderness is more reliable than palpation for tissue texture change. Indirect evidence from animal studies and experimental muscle inflammation support the plausibility of protective paraspinal muscle contraction. Increased paraspinal electromyographic (EMG) activity observed in subjects with LBP appears to be a result of voluntary and nonvoluntary changes in motor control, modified by psychophysiological responses to perceived stress rather than a simple protective reflex. CONCLUSION: Although little direct evidence exists of the nature of clinically detected paraspinal tissue texture change, the concept of reactive muscle contraction appears plausible. Increased paraspinal EMG activity associated with LBP does not appear to be mediated by a simple protective reflex.

Electromyography↗
PubMed2002

Occurrence of a food poisoning incident by palytoxin from a serranid Epinephelus sp. in Japan.

Between October 30 and November 4, 2000, eleven persons were intoxicated due to ingestion of a serranid fish Epinephelus sp. in Kochi Prefecture, Japan. Their symptoms were mainly featured by severe muscle pain, low back pain, and discharge of black urine. Serum creatine phosphokinase (CPK) levels of victims were higher (700-23,800 IU/l) than normal values, and their recovery times were more than one month. Immediately after the incident, the leftovers were collected for investigation. The causative agent was identified as palytoxin (PTX) on the basis of delayed haemolytic activity which was inhibited by an anti-PTX antibody and ouabain (g-strophanthin). To our knowledge, this is the first report on palytoxin poisoning with serranid fish.

Acrylamides↗