Although light microscopic features of muscle are not pathognomonic in most cases of myasthenia gravis (MG), careful examination of neuromuscular junction by electron microscopy (EM) can reveal important clues for this disease. We report here a case of MG confirmed by EM study to emphasize that tissue diagnosis is still the best adjuvant to confirm the diagnosis. An 18-year-old female visited our hospital complaining of progressive muscle weakness for 3 years. She had difficulty in running, going upstairs and doing routine activities. Symptoms were aggravated with continuous work and resolved after rest. She had weakness of bilateral masseter and facial muscles and proximal portions of extremities without definite diurnal variation. Electromyography showed myopathic changes in proximal muscles of extremities. MG was considered but tensilon test was equivocal. Repetitive nerve stimulation tests revealed 20-30 percent decrease in responses to low and high rate stimulation. Muscle biopsy revealed selective type 2 atrophy. Ultrastructurally, abnormalities of neuromuscular junctions, i.e., wide primary synaptic cleft, and wide and shallow secondary synaptic clefts with mild myopathic features were present. These findings were pathognomonic for MG. Later, her symptoms were improved completely 3 months after thymectomy. The histologic finding of thymus was follicular hyperplasia.
Adolescence ; Biopsy ; Case Report ; Female ; Human ; Microscopy, Electron ; Mitochondria/ultrastructure ; Mitochondria/pathology ; Muscle, Skeletal/ultrastructure ; Muscle, Skeletal/pathology ; Muscle, Skeletal/enzymology ; Myasthenia Gravis/pathology* ; Myofibrils/ultrastructure ; Myofibrils/pathology ; Myosin ATPase/analysis ; Neuromuscular Junction/ultrastructure* ; Neuromuscular Junction/pathology*

Although light microscopic features of muscle are not pathognomonic in most cases of myasthenia gravis (MG), careful examination of neuromuscular junction by electron microscopy (EM) can reveal important clues for this disease. We report here a case of MG confirmed by EM study to emphasize that tissue diagnosis is still the best adjuvant to confirm the diagnosis. An 18-year-old female visited our hospital complaining of progressive muscle weakness for 3 years. She had difficulty in running, going upstairs and doing routine activities. Symptoms were aggravated with continuous work and resolved after rest. She had weakness of bilateral masseter and facial muscles and proximal portions of extremities without definite diurnal variation. Electromyography showed myopathic changes in proximal muscles of extremities. MG was considered but tensilon test was equivocal. Repetitive nerve stimulation tests revealed 20-30 percent decrease in responses to low and high rate stimulation. Muscle biopsy revealed selective type 2 atrophy. Ultrastructurally, abnormalities of neuromuscular junctions, i.e., wide primary synaptic cleft, and wide and shallow secondary synaptic clefts with mild myopathic features were present. These findings were pathognomonic for MG. Later, her symptoms were improved completely 3 months after thymectomy. The histologic finding of thymus was follicular hyperplasia.
Adolescence ; Biopsy ; Case Report ; Female ; Human ; Microscopy, Electron ; Mitochondria/ultrastructure ; Mitochondria/pathology ; Muscle, Skeletal/ultrastructure ; Muscle, Skeletal/pathology ; Muscle, Skeletal/enzymology ; Myasthenia Gravis/pathology* ; Myofibrils/ultrastructure ; Myofibrils/pathology ; Myosin ATPase/analysis ; Neuromuscular Junction/ultrastructure* ; Neuromuscular Junction/pathology*

OBJECTIVE: To observe ultrastructure changes of electrical injury in rats. METHODS: An experimental model of rats suffered from the low voltage were designed. Ultrastructure changes of electrical injured tissues were observed under transmission electron microscope. RESULTS: (1) Plasma of epithelium was concreted in the affected areas and inner membrane system was broken. (2) Hypercontraction bands were observed in skeleton muscles. (3) There was dissolved necrosis and hypercontraction bands in the myocardium. (4) Vacuoles were found in plasma of endothelium of blood vessels on electrical current path, and myelin sheath of nerve fiber were loosed. CONCLUSION The above mentioned ultrastructure changes could be used as assistant diagnostic index of electrocution. The mechanism of the changes were discussed.
Animals ; Electric Injuries/pathology* ; Muscle, Skeletal/ultrastructure* ; Nerve Fibers/ultrastructure* ; Rats ; Rats, Sprague-Dawley

OBJECTIVE: To study the pathological changes of genioglossus with transmission electron microscope (TEM) in patients with obstructive sleep apnea hypopnea syndrome (OSAHS) dominated by lingual region obstruction, and to explore the role of tongue organizations in the pathogenesis and its clinical significance. METHOD: Thirty-eight cases of genioglossus were collected from the patients received UPPP and partial glossectomy (3060 severe group 15 cases), 6 adult patients without oropharyneal and hypopharyneal obstructive disease received tongue tumor resection or trauma debridement surgery were collected as control group. The features of morphological changes in genioglossus were observed by TEM. RESULT: Under the TEM, in the control group,the muscle fibers of the genioglossus organization arranges regular, mitochondrial shape between muscle was regular; The below 3 kinds of variations existed simultaneously in all genioglossus specimens of all the OSAHS patients. In the mild group, myofibrillar atrophied, arranged sloppily, the gap was increased, localized filaments were edema, connective tissue between muscle bundles was proliferated, mitochondria were swelling, some were spherical, crests were still clear; In the moderate group, myofibrillar obviously atrophied with different diametric sizes and disorderliness, the Z lines were shortened or distorted, part of the myofibrillar ruptured, dissolved or disappeared, the connective tissues between muscle bundles were obviously proliferated, mitochondria were swellen, vacuolar degeneration, crests were vague, shorten and irregulatio; In the severe group, a large number of myofibrillar were fractured, dissolved, disorganized, integrated condensate lumpy, spotty or flake arranged, Z-lines were distorted or disappeared. Mitochondria were sizes, showed vacuolar degeneration, crests were disappeared, some changes were flocculent, mitochondria accumulation phenomenon was visible in some samples. Moreover, with the AHI increased, the occurence ratio of mild changes was decreased while severe changes occurence ratio increased. CONCLUSION The changes of genioglossus and mitochondrial in OSAHS patients is a continuous, progressive process, moverover, with the aggravation of OSAHS, genioglossus histopathological changes had gradually worsening tendency.
Adult ; Glossectomy ; Humans ; Mitochondria ; Muscle, Skeletal ; pathology ; ultrastructure ; Sleep Apnea, Obstructive ; complications ; Tongue ; pathology

Actins ; metabolism ; Adult ; Desmin ; metabolism ; Electromyography ; Humans ; Male ; Microscopy, Electron, Transmission ; Muscle, Skeletal ; pathology ; ultrastructure ; Myopathies, Nemaline ; metabolism ; pathology

OBJECTIVETo document ultrastructural changes of brain, spinal cord, skeletal muscle, jejunum and lung of EV71 infection mouse model, and to explore the myotropism and pathogenesis of EV71 in nervous system.

METHODSTen-day-old suckling mice were infected with EV71 strain via the intraperitoneal route. Mice with paralysis were scarified on day 4 post infection and the brain, spinal cord, skeletal muscle, jejunum and lung were sampled for transmission electron microscopy and light microscopy.

RESULTSLesions in brain were generally mild with inner chamber swelling in some of mitochondria. Myelin sheaths of medullated fibers were split with vacuolated changes. The Nissl bodies in anterior motor neurons disappeared along with mitochondria swelling, rough endoplasmic reticulum swelling and degranulation. Cytoplasm of anterior motor neurons showed cribriform appearance accompanied by neuronophagia. The bands of skeletal muscle in the infected group disappeared with degeneration and karyopyknosis in myocytes, in addition to mitochondrial swelling. Microvilli of epithelium in jejunum became loosely arranged along with formation of spiral medullary sheath structure and mitochondria swelling. Interstitial pneumonia was observed in lungs with type II pneumocyte proliferation and evacuation of the multilamellar bodies.

CONCLUSIONSEV71 infection causes severe myositis in the mouse model suggesting a strong myotropism of EV71 virus. The presence of lesions of various degrees in central nervous system and changes in anterior motor neurons may be associated with limb paralysis.

Animals ; Brain ; ultrastructure ; virology ; Disease Models, Animal ; Enterovirus A, Human ; Enterovirus Infections ; pathology ; virology ; Jejunum ; ultrastructure ; virology ; Lung ; ultrastructure ; virology ; Mice ; Mice, Inbred BALB C ; Microscopy, Electron, Transmission ; Muscle, Skeletal ; ultrastructure ; virology ; Spinal Cord ; ultrastructure ; virology

We report a first Korean case of presumably dominantly inherited primary tubular aggregate myopathy in a 19-yr-old man, who presented with slowly progressive proximal muscle stiffness and weakness. In hematoxylin and eosin stain, it showed subsarcolemmal, or central pale basophilic granular vacuoles, which stained red with modified Gomori's trichrome and intensive blue with nicotinamide adenonine dinucleotide-tetrazolium reductase, respectively. Ultrastructurally, aggregates of 60 nm-sized hexagonal tubules were found in both type 1 and type 2 fibers. We briefly review the pathologic findings of the previously reported cases of tubular aggregate myopathy and discuss the possible pathogenesis of this disease. We briefly discuss the possible pathogenesis of sarcoplasmic reticulum and review the ultrastructural characteristics.
Adult ; Biopsy ; Frozen Sections ; Genes, Dominant ; Genes, Recessive ; Human ; Korea ; Male ; Microscopy, Electron ; Microtubules/ultrastructure ; Mitochondria, Muscle/ultrastructure ; Muscle, Skeletal/pathology* ; Myopathies, Structural, Congenital/diagnosis ; Myopathies, Structural, Congenital/genetics ; Myopathies, Structural, Congenital/pathology* ; Pedigree

Recently apoptotic cell death has been reported in differentiated skeletal muscle, where apoptosis was generally assumed not to occur. To investigate whether apoptosis may contribute to the steroid-induced myopathy, rats treated with triamcinolone acetonide (TA) for 9 days were sacrificed for detecting apoptosis by in situ end labeling (ISEL) and electron microscopy in the soleus muscles. Immunohistochemical stainings of Fas antigen and p53 protein were performed to examine whether apoptosis-related proteins were present in the myopathy. Muscle fiber necrosis and apoptotic myonuclei appeared in the soleus muscles following administration of TA, while control muscles showed no evidences for apoptosis. Fas antigen was not detected in control muscles, but expressed in the soleus muscles of steroid-induced myopathy. Some of the Fas antigen-expressing muscle fibers were positive for ISEL. p53 protein was not detected in any muscle fibers. These findings indicate that TA can induce apoptosis in differentiated skeletal muscles, and Fas antigen might be partly related to apoptotic muscle death in steroid-induced myopathy.
Animal ; Antigens, CD95/analysis ; *Apoptosis ; Female ; Immunohistochemistry ; Microscopy, Electron ; Muscle, Skeletal/*pathology/ultrastructure ; Muscular Diseases/chemically induced/*pathology ; Protein p53/analysis ; Rats ; Rats, Sprague-Dawley ; Triamcinolone Acetonide/*toxicity

OBJECTIVETo investigate the effect of therapeutic ultrasound-induced microbubble destruction on the microcirculation of rat skeletal muscle.

METHODSThirty SD rats were randomized into 5 groups (n=6), namely normal saline, microbubble, ultrasound, high-energy ultrasound microbubble and low-energy ultrasound microbubble groups. Before and after the treatments, the diameter and blood flow velocity in the microvessels in the skeletal muscle were measured, and the structural changes of the injured microvessels observed by electron microscopy.

RESULTSMicrobubble cavitation did not produce significant effect on the mean arterial pressure and diameter of microvessels in rat skeletal muscle (P>0.05), but the blood flow velocity was obviously lowered and blood flow volume reduced in the microvessels. The reduction of the flow velocity and blood flow volume and their subsequent recovery were associated with ultrasound energy, and in the low ultrasound energy group, the flow velocity and blood flow volume in the of venules recovered obviously after about 15 min, which, however, took approximately 1 h for the arterioles. In contrast, recovery of the flow velocity and blood flow volume in the microvessels took more than 2 h in the high ultrasound energy group. Cavitation resulted in endothelium cell rupture, widening of the endothelial interspace and entry of the red blood cells into the extravascular tissues as revealed by electron microscopy, but no rupture of the lining endothelium was observed 2 h after the treatment.

CONCLUSIONSEndothelium cell rupture induced by microbubble cavitation may affect the local microcirculation, and lower ultrasound energy exposure is associated with milder endothelial injury and more rapid recovery.

Animals ; Blood Flow Velocity ; Blood Vessels ; pathology ; physiopathology ; Endothelial Cells ; pathology ; ultrastructure ; Female ; Male ; Microbubbles ; Microcirculation ; Microscopy, Electron ; Microspheres ; Muscle, Skeletal ; blood supply ; Rats ; Rats, Sprague-Dawley ; Ultrasonics

Animals ; Bone Matrix ; pathology ; Bone and Bones ; pathology ; Collagen Type I ; metabolism ; Collagen Type III ; metabolism ; Disease Models, Animal ; Humans ; Muscle, Skeletal ; metabolism ; pathology ; Osteoblasts ; pathology ; ultrastructure ; Osteoclasts ; pathology ; Osteocytes ; pathology ; Osteogenesis Imperfecta ; classification ; metabolism ; pathology ; Skin ; pathology