OBJECTIVETo study the degeneration and regeneration of skeletal muscle after denervation.

METHODSDenervation was carried out in gastrocnemius muscles in 30 adult BALB/C mice by cutting the sciatic nerve. The gastrocnemius muscles were removed at 1, 2, 4, 8, 12, 16 weeks after denervation, respectively. Specimens were processed for histological study and immunohistochemical technique.

RESULTSMuscle fiber atrophy followed by degerneration and regeneration was observed in the early period of denervation. Fusion of the regenerated muscle cells with each other followed by degeneration of the cells and growth of fibro-connective tissue were observed in the later stage. The expression of myoglobin and actin decreased in 1-4 weeks after denervation. The postive expression of the proteins was observed in some 8 weeks' cells and in many degenerated 12-14 weeks' muscle cells.

CONCLUSIONDegeneration and regeneration may coexisted in the denervated muscles. The regenerated muscle cells can't fully develop due to the deficit of nerve regulation and degenerate again. The regenerated muscle cells will melt each other and can't develop to mature muscle fiber in the later stage.

Animals ; Female ; Mice ; Mice, Inbred BALB C ; Muscle Denervation ; Muscle Fibers, Skeletal ; pathology ; Muscle, Skeletal ; innervation ; physiology ; Muscular Atrophy ; physiopathology ; Nerve Regeneration ; physiology ; Sciatic Nerve ; physiology ; surgery

OBJECTIVE: This study aimed to clarify the morphology of the Martin-Gruber anastomosis (MGA) in Chinese. METHODS: One hundred and five Chinese upper limbs (36 males and 20 femalese) were dissected to find the connections between medial nerve and ulnar nerve. The MGA was classified as previously described by Lee. RESULTS: MGA was found in 24 cases (22.9%), in 11 of the 36 male and 5 of the 20 female. There was no obvious difference in the frequency of MGA in both upper limbs. Most MGA ulnar position was located at the medial and distal segment of the forearm. CONCLUSION MGA anatomy could play important role in forensic diagnosis of ulnar nerve injury in Chinese population.
Cadaver ; China/epidemiology* ; Expert Testimony/legislation & jurisprudence* ; Female ; Humans ; Male ; Median Nerve/pathology* ; Muscle, Skeletal/innervation* ; Nervous System Malformations/physiopathology* ; Ulnar Nerve/pathology* ; Upper Extremity/innervation*

Disfigurement of body contour, caused by excessive muscular hypertrophy, can seldom be effectively and safely corrected by lipectomy, liposuction or combined partial myomectomy. This study was conducted to obtain basic knowledge for the development of a safe and effective method of treating patients with excessive and unwelcome muscle hypertrophy. Accordingly, we developed a new experimental rat model, consisting of the peroneal nerve and its target muscles - the anterolateral crural muscle group. After severance of 1/4, 1/2, and 1/1 of the peroneal nerve, functional parameters based on gross movement and electrophysiologic data were monitored. Changes in the external circumference and weight of the anterolateral crural muscle were documented and compared with control sides. Histologic and histomorphometric parameters of the muscle were also documented. Average takeoff latency in 1/4 and 1/2 neurotomy groups was increased to 130% and 154% of the control at 3 months, and 156% and 149% of control at 6months, respectively. Similarly, average peak-to-peak compound action potentials were 72% and 59% of the control at 3months and 57% and 50% of control at 6months. No definite gait disturbances were evident in the partial neurotomy groups. Maximal circumferences of the anterolateral crural muscle group were significantly reduced to 86%, 71% and 66% of the control in the 1/4, 1/2 and 1/1 neurotomy groups at 3 months (p < 0.001), and to 74%, 68% and 64% of the control at 6 months, respectively (p < 0.001). The corresponding weights were 76%, 62%, and 50% of the control sides at 3 months, and 70%, 56%, and 48% at 6 months in 1/4, 1/2 and 1/1 neurotomy groups. Histograms drawn showing the number of muscle fibers per mm2 in cross-sections, showed a total number of 239 +/- 52 in the control group; the size of muscle fibers was mainly medium to large. The more extensive the neurotomy, the greater the was the number of small angulated muscle fibers, up to a total of 1,564 +/- 211. Although more research work and clinical trials are required, we believe that selective neurotomy has the potential of being an effective tool for reducing muscle bulk, and avoiding apparent muscular dysfunction and complications.
Animal ; Electromyography ; Hindlimb ; Hypertrophy ; Muscle, Skeletal/*innervation/*pathology/physiopathology ; Muscular Diseases/*surgery ; Peroneal Nerve/*surgery ; Rats ; Rats, Sprague-Dawley

We experienced a rare case of winged scapula that was caused by the rupture of the rhomboideus major and the lower trapezius muscles without any nerve injury in a 12 yr old female after she had carried a heavy backpack. Electrodiagnostic study revealed that the onset latencies, amplitudes and conduction velocities were normal in the long thoracic nerve, the spinal accessory nerve and the dorsal scapular nerve. The needle EMG findings were normal as well. An explorative operation was performed and the rupture of the rhomboideus major and lower trapezius muscles was detected. Direct surgical repair of the ruptured muscle was carried out and the deformity was corrected. The anatomical and functional restoration was satisfactorily accomplished.
Weight Lifting/injuries ; Thoracic Nerves/*injuries ; Scapula/anatomy & histology/*physiopathology ; Rupture ; Neurons/metabolism ; Muscle, Skeletal/*injuries/innervation/*pathology ; Humans ; Female ; Electromyography/*methods ; Child

To study the effects of ciliary neurotrophic factor (CNTF) on denervated skeletal muscle atrophy and to find a new approach to ameliorate atrophy of denervated muscle, a model was established by cutting the right sciatic nerve in 36 Wistar mice, with the left side serving as control. Then they were divided into two groups randomly. CNTF (1 U/ml) 0.1 ml was injected into the right tibial muscle every day in experimental group, and saline was used into another group for comparison. The muscle wet weight, muscle total protein, Ca2+, physiological response and morphology were analyzed on the 7th, 14th and 28th day after operation. Our results showed that compared to control group, there was a significant increase in muscle wet weight, total protein, Ca2+, muscle fiber cross-section area in CNTF group (P < 0.05). CNTF could ameliorate the decrease of tetanic tension (PO), post-tetanic twitch potentiation (PTP), and the prolonged muscle relaxation time (RT) caused by denervation (P < 0.05). The motor end-plate areas 7 days and 14 days after denervation was similar (P > 0.05), but significantly larger 28 days after the denervation (P < 0.05). Our results suggest that CNTF exerts myotrophic effects by attenuating the morphological and functional changes associated with denervation of rat muscles and has protective effects on denervated muscle and motor end plate.
Animals ; Ciliary Neurotrophic Factor ; pharmacology ; Male ; Motor Endplate ; pathology ; physiopathology ; Muscle Denervation ; adverse effects ; Muscle, Skeletal ; innervation ; pathology ; physiopathology ; Muscular Atrophy ; etiology ; prevention & control ; Random Allocation ; Rats ; Rats, Wistar ; Sciatic Nerve ; surgery

BACKGROUND/AIMS: We investigated the electromyography (EMG) findings and demographic, clinical, and laboratory features that may predict the development of malignancy in patients with idiopathic inflammatory myopathy (IIM). METHODS: In total, 61 patients, 36 with dermatomyositis and 25 with polymyositis, were included. Patients were divided into those with and without malignancies, and comparisons were made between the groups in terms of their demographic, clinical, laboratory, and EMG findings. RESULTS: The frequencies of malignancies associated with dermatomyositis and polymyositis were 22% and 8%, respectively. Patients with malignancies showed a significantly higher incidence of dysphagia (odds ratio [OR], 21.50; 95% confidence interval [CI], 3.84 to 120.49), absence of interstitial lung disease (ILD; OR, 0.12; 95% CI, 0.01 to 0.98), and complex repetitive discharge (CRD) on the EMG (OR, 26.25; 95% CI, 2.67 to 258.52), versus those without. After adjustment for age, dysphagia and CRD remained significant, while ILD showed a trend for a difference but was not statistically significant. Multivariate analysis revealed that the CRD conferred an OR of 25.99 (95% CI, 1.27 to 531.86) for malignancy. When the frequency of malignancy was analyzed according to the number of risk factors, patients with three risk factors showed a significantly higher incidence of malignancy, versus those with fewer than two (p = 0.014). CONCLUSIONS: We demonstrated for the first time that CRD on the EMG was an additional independent risk factor for malignancy in IIM. Further studies on a larger scale are needed to confirm the importance of CRD as a risk factor for malignancy in IIM.
Action Potentials ; Adult ; Aged ; Dermatomyositis/complications/*diagnosis/physiopathology ; *Electromyography ; Female ; Humans ; Logistic Models ; Male ; Middle Aged ; Multivariate Analysis ; Muscle, Skeletal/*innervation/pathology ; Neoplasms/*etiology ; Odds Ratio ; Polymyositis/complications/*diagnosis/physiopathology ; Predictive Value of Tests ; Retrospective Studies ; Risk Factors