Overaction of the inferior oblique(IO) muscle is manifested by elevation of the adducted eye and from the clinical point of view there are two types of overaction. The primary type is of unknown cause, whereas the secondary type is usually related to the palsy of the ipsilateral superior oblique or contralateral superior rectus. An ultrastructural study on the overacting IO muscles was performed compared to normal IO muscles by electron microscopy. Of 16 biopsies of overacting IO muscles, four had primary overacting inferior obliques and twelve had secondary overacting inferior obliques due to paralysis of superior oblique muscle. Additional four IO muscle, obtained from patients with intraocular diseases served as control specimens. The most striking abnormalities were aggregations of mitochondria and degenerating mitochondrial profiles and increased vacuolization in primary and secondary overacting muscles. Many muscle fibers were in different stages of atrophy, and hypertrophy and regeneration of muscle fibers were sometimes visible. The results suggest that the primary overacting IO muscle might be the result of a paresis of the superior oblique muscle.
Biopsy ; Humans ; Mitochondria/ultrastructure ; Ocular Motility Disorders/*pathology ; Oculomotor Muscles/*ultrastructure ; Ophthalmoplegia/pathology ; Vacuoles/ultrastructure

Leigh's disease is a rare progressive neurological disorder that is characterized light microscopically by focal spongy necrosis in the brain and electron microscopically by mitochondriopathy. We report an autopsy case of Leigh's disease that showed abnormalities in the liver, kidney and skeletal muscle as well as the central nervous system. The patient was an 18-month-old girl who has carried a diagnosis of cerebral palsy ever since her birth to a 20-year-old mother. The baby was generally hypertonic and mentally retarded. She died of severe metabolic acidosis. Postmortem examination showed growth retardation, fatty liver, fatty kidney and soft brain. Brain section showed multifocal softenings in the brainstem, basal ganglia and periventricular areas. Microscopically increased capillaries with endothelial proliferation, vacuolar degeneration and mild gliosis were seen in the brain. The axons were relatively preserved. Liver and kidneys showed microvesicular fatty change. Myofiber degeneration of the skeletal muscle was also noted. Electron microscopic examination showed markedly increased mitochondria in the parenchymal cells of the brain, liver and kidney. The mitochondria showed round to ovoid ballooned appearance including electron-dense core-like structures and pseudoinclusions of glycogen granules.
Brain/pathology/ultrastructure ; Female ; Humans ; Infant ; Kidney/pathology/ultrastructure ; Leigh Disease/*pathology ; Liver/pathology/ultrastructure ; Mitochondrial Encephalomyopathies/pathology ; Muscles/pathology

OBJECTIVETo study the effects of repeated + Gz forces on masticatory muscles.

METHODS48 male Wistar rats were randomly divided into 4 groups. Group A was normally fed. Group B was only fixed with rat-kept devices for 5 minutes. Group C was borne + 1 Gz for 5 minutes. Group D was repeatedly exposed + 10 Gz (each for 30 s, onset rate about 0.5 G/s, 5 times/d with + 1 Gz 1 minute intervals, 4 d/wk, 3 weeks in total). The histological changes of the masseter, temporal and lateral pterygoid muscles were observed.

RESULTSNo abnormal changes were observed in Group A, B and C. But pathological changes could be found in group D. The wrench and deformation of muscular fibers, the dissolution of partial myofibril, the swelling of mitochondria, the reduce of hepatin from the masseter and lateral pterygoid muscles could be found.

CONCLUSIONSRepeated + Gz stresses could induce the damage of masticatory muscles in different degrees.

Animals ; Hypergravity ; Male ; Masseter Muscle ; pathology ; ultrastructure ; Masticatory Muscles ; pathology ; ultrastructure ; Microscopy, Electron ; Pterygoid Muscles ; pathology ; ultrastructure ; Rats ; Rats, Wistar ; Temporal Muscle ; pathology ; ultrastructure ; Time Factors

Chronic progressive external ophthalmoplegia (CPEO) is a rare clinical syndrome characterized by slowly progressive paralysis of extraocular muscles. We report a male patient who had a 20 year history of CPEO. Histological examination of left deltoid muscle showed characteristic ragged red fibers. Electron microscopy revealed a number of abnormal mitochondria which contain paracrystalline inclusion bodies.
Biopsy ; Chronic Disease ; Humans ; Male ; Middle Aged ; Mitochondria/ultrastructure ; Muscles/ultrastructure ; Ophthalmoplegia/*diagnosis/pathology

Central core disease is a rare congenital myopathy characterized by the formation of cores that consist of abnormal arrangement of myofibrils inside the myofibers. We report a 5-year-old Korean girl who showed a fairly typical clinical course of non-progressive muscle weakness. Electrodiagnostic studies showed low-amplitude polyphasic electromyograph and normal nerve conduction velocity. Gastrocnemius muscle biopsy showed central cores in over 80% of the fibers on H&E section. Histochemistry revealed deficient or absent mitochondrial enzyme in the cores and type I predominance. Ultrastructurally both structured and non-structured cores were found separately or simultaneously in one fiber. This case is the first report in the Korean literature.
Child, Preschool ; Female ; Humans ; Microscopy, Electron ; Muscles/pathology/ultrastructure ; Muscular Diseases/*congenital/*pathology

Multicore myopathy is a rare congenital myopathy. The multicores consist of numerous small areas of decreased oxidative enzyme activity. The long axis of the lesion is perpendicular or parallel to the long axis of the muscle fiber. These cores are usually smaller than central cores. For this reason they are also called minicores. Although the multicores represent a nonspecific change in that they can be observed in malignant hyperthermia, muscular dystrophy, inflammatory myopathy, etc. Muscular weakness dating from early infancy is combined large proportion of the muscle fibers. In about half of the reported cases the muscular weakness has not been progressive, while in the others a slow progression has occurred. This 9-year-old boy presented with congenital nonprogressive myopathy associated with thoracic scoliosis and bilateral equinovarus deformity. The serum creatine phosphokinase and lactic dehydrogenase levels were normal. Electromyography showed "myopathic" features. The biopsy revealed a marked size variation in myofibers, ranging from 10 microns to 100 microns. A few small angular fibers and slight endomyseal fibrosis were also noted. There was type I fiber predominance. NADH-TR reaction disclosed more well-defined cores with loss of intermyofibrillary mitochondrial activity. These cores were usually located with loss of intermyofibrillary mitochondrial activity. These cores were usually located in the peripheral portions of the myofibers and the core size measured 10-30 microns in diameter. Electron microscopic examination revealed circumscribed areas of disintegrated Z band material and disorganized sarcomeric units near the sarcolemma. A decrease in the number of mitochondria and glycogen particles was noted.
Biopsy ; Child ; Histocytochemistry ; Humans ; Korea ; Male ; Microscopy, Electron ; Muscles/pathology/ultrastructure ; Muscular Diseases/*pathology

OBJECTIVE: To investigate histopathologic and ultrastructural changes of extraocular muscles (EOM) in thyroid associated ophthalmopathy (TAO). METHODS: Twelve EOM specimens from 11 patients with TAO were observed. Each of the specimen was stained with HE and observed by light microscope,and then was sectioned with ultrathin method and observed by transmission electronic microscope. RESULTS: Under the light microscope, sarcoplasm coagulation,granular degeneration, vacuolization and necrosis were found in the extraocular muscular cells.Under the electronic microscope, there were disturbance and disappearance of the Z line in part of muscular fibers and various degrees of sarcoplasmic reticulum dilatation, myofilament lysis and destruction with formation of vacuoles.In severe cases,the muscular cells could be completely destroyed and phagocytosed by macrophages,fibrosis occurred and myofibroblasts were found in some cases. CONCLUSION The extraocular muscles in TAO are destroyed at various degrees,and the muscular cells may be the target cells in TAO.
Adult ; Aged ; Female ; Graves Ophthalmopathy ; pathology ; Humans ; Male ; Middle Aged ; Oculomotor Muscles ; pathology ; ultrastructure

PURPOSE: To analyze innervated myotendinous cylinders (IMCs) in the extraocular muscles (EOMs) of normal subjects and strabismic patients. METHODS: The rectus muscles of 37 subjects were analyzed. Distal myotendinous specimens were obtained from 3 normal subjects, 20 patients with acquired strabismus, 11 with infantile strabismus, and from 3 with congenital nystagmus, and were studied by using light microscopy. Some specimens (6 rectus muscles) were also examined by transmission electron microscopy. RESULTS: IMCs were found in the distal myotendinous regions of EOMs. The IMCs of patients with acquired strabismus showed no significant morphological alterations. However, significant IMCs alterations were observed at the distal myotendinous junction of patients with congenital strabismus and congenital nystagmus. CONCLUSIONS: This study supports the notion that IMCs in human EOMs function mainly as proprioceptors, along with effector properties, and a disturbance of ocular proprioceptors plays an important role in the pathogenesis of oculomotor disorder. We suggest that a proprioceptive feedback system should be stimulated and calibrated early in life for the development of binocular vision.
Adolescent ; Adult ; Child ; Child, Preschool ; Female ; Humans ; Infant ; Male ; Microscopy, Electron, Transmission ; Middle Aged ; Oculomotor Muscles/*innervation/physiopathology/ultrastructure ; Proprioception/physiology ; Strabismus/*pathology/physiopathology ; Young Adult

The purpose of this study were 1) to determine the earliest pathological changes of germanium dioxide (GeO2)-induced myopathy; 2) to determine the pathomechanism of GeO2-induced myopathy; and 3) to determine the minimal dose of GeO2 to induce myopathy in rats. One hundred and twenty five male and female Sprague-Dawley rats, each weighing about 150 gm, were divided into seven groups according to daily doses of GeO2. Within each group, histopathological studies were done at 4, 8, 16, and 24 weeks of GeO2 administration. Characteristic mitochondrial myopathy was induced in the groups treated daily with 10 mg/kg of GeO2 or more. In conclusion, the results were as follows: 1) The earliest pathological change on electron microscope was the abnormalities of mitochondrial shape, size and increased number of mitochondria; 2) The earliest pathological change on light microscope was the presence of ragged red fibers which showed enhanced subsarcolemmal succinate dehydrogenase and cytochrome c oxidase reactivity; 3) GeO2 seemed to affect the mitochondrial oxidative metabolism of muscle fibers; 4) GeO2 could induce mitochondrial myopathy with 10 mg/kg of GeO2 for 4 weeks or less duration in rats.
Animal ; Cytochrome-c Oxidase/metabolism ; Female ; Germanium/toxicity* ; Histocytochemistry ; Male ; Mitochondrial Myopathies/pathology ; Mitochondrial Myopathies/enzymology ; Mitochondrial Myopathies/chemically induced* ; Muscles/ultrastructure ; Muscles/enzymology ; Rats ; Rats, Sprague-Dawley ; Succinate Dehydrogenase/metabolism