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Biomedical subjects

I Nonaka

Publications and source records attributed to I Nonaka.

At least 325 records · Page 18Linked to original sources

Congenital nemaline myopathy with dilated cardiomyopathy: an autopsy study.

A 3-year-old boy with congenital nemaline myopathy had generalized muscle weakness and hypotonia since birth. He developed cardiac symptoms at 2 years of age and died from congestive heart failure. At autopsy, the heart was markedly dilated, involving both ventricles. Rod bodies were recognized not only in skeletal muscles but in cardiac muscles on light and electron microscopy. Desmin and alpha-actinin, which constitute Z-line protein, were shown to localize in the rod structures in both skeletal and myocardial cells by immunohistochemistry. Seven cases of nemaline myopathy with cardiomyopathy have been reported in the literature. All of these patients were over 20 years of age, and the condition appeared mostly in the adult onset and the asymptomatic forms. This is the first infantile case of congenital nemaline myopathy which showed dilated cardiomyopathy with a fatal outcome.

Cardiomyopathy, Dilated↗

Complete external ophthalmoplegia in a patient with congenital myopathy without specific features (minimal change myopathy).

An 11-month-old female infant with mild asphyxia at birth had severe generalized muscle hypotonia and weakness, predominantly in the neck flexors, a high-arched palate and a funnel chest from early infancy. Her facial muscles were also markedly involved. In addition, she showed striking non-progressive, complete external ophthalmoplegia and mild ptosis. A muscle biopsy specimen showed non-specific myopathic changes, including mild variation in fiber size, mild type 1 fiber predominance, type 2B fiber deficiency and slightly increased acid phosphatase activity. Complete ophthalmoplegia may thus be seen not only in myotubular myopathy but also in various forms of congenital non-progressive myopathy.

Abnormalities, Multiple↗

Antibody against the C-terminal portion of dystrophin crossreacts with the 400 kDa protein in the pia mater of dystrophin-deficient mdx mouse brain.

The mdx mouse is an animal model for X-linked Duchenne muscular dystrophy. A polyclonal antibody against a synthetic peptide IV equivalent to the C-terminal portion (amino acids 3495-3544) of dystrophin crossreacted with a 400 kDa protein in the brain and the spinal cord of mdx mouse, as well as in the control B10 mouse. However, the protein did not crossreact with the polyclonal antibody raised against the N-terminal portion of dystrophin peptide I (amino acids 215-264). Immunofluorescent micrography revealed that the outside of the small arteries and the pia mater of the brain strongly reacted with the anti-peptide IV antibody. These results strongly suggest the presence of a crossreactive protein other than dystrophin, possibly a dystrophin-related autosomal gene product, in the pia mater.

Animals↗

[A case of complex I deficiency with episodic respiratory distress].

A 7-year-old girl with normal psychomotor development during infancy began to have easy fatigability about 3 years of age. At the age of 5 years, she developed respiratory distress and became unconscious when the serum lactate and pyruvate levels were markedly elevated and a blood gas analysis showed respiratory and metabolic acidosis. Thereafter, she had similar episodic respiratory problems with lactic acidosis. Her muscle biopsy showed a myopathic pattern and numerous ragged-red fibers in an approximately half of muscle fibers. Lipid droplets were slightly to moderately increased in amount mostly in the ragged-red fibers. A biochemical analysis on the isolated mitochondria from the biopsied sample showed markedly decreased NADH cytochrome c reductase activity with no specific but rather uniformly decreased subunits of complex I by the immunoblotting method. She was diagnosed as having the myopathic form of complex I deficiency because she and her relatives with similar muscle symptoms had no central nervous system symptoms such as progressive mental deterioration, convulsions and stroke-like episodes. Diagnosis of complex I deficiency was further confirmed by an oxograph study; the oxygen consumption was not detectable when malate and pyruvate were added as the substrates in the isolated mitochondria. Although stroke-like episodes and convulsions are commonly seen in complex I deficiency, episodic respiratory distress as seen in the present patient has not been described in the literature.

Child↗

[Mitochondrial encephalomyopathy (focal cytochrome c oxidase deficiency) with transient episodes of muscle weakness and elevation of serum creatine kinase activity].

A 17-year-old boy who had mitochondrial encephalomyopathy with focal deficiency of cytochrome c oxidase (CCO) activity is described. He experienced 3 episodes of muscle weakness, fatigability, nausea, vomiting and concomitant increase of serum creatine kinase activity, at the age of 13, 15 and 17 years. During interval there was no muscle weakness and the serum creatine kinase activity was within normal range. Increased levels of lactic acid and pyruvic acid were observed in the blood and cerebrospinal fluid. After an aerobic exercise test, lactic acid and pyruvic acid in the blood increased to an abnormally high level, and the arterial blood became acidic (pH 7.297). On EEG, occasional intermittent irregular theta activities were observed in the anterior region, but there were no abnormalities on CT and MRI in the central nervous system. In the biopsied muscle, ragged-red fibers comprised 20% on modified Gomori-trichrome staining and a number of fibers with no CCO activity were scattered throughout. The CCO activity in the mitochondria isolated from the biopsied muscle was reduced to 49.2 nmol/min/mg protein (normal range 144.7-355.8), while other mitochondrial enzyme activities in the electron transport system were normal. From these data, the patient was considered to have a unique form of mitochondrial encephalomyopathy. By the administration of a large amount of coenzyme Q10, episodes of muscle weakness and nausea, and an increase of lactic acid and pyruvic acid in the blood after aerobic exercise test were no longer observed.

Adolescent↗

[Clinical and pathological studies on two patients with adult-onset nemaline myopathy].

Clinical and pathological findings of two patients, a 44-year-old male and a 54-year-old female, with adult-onset nemaline myopathy were described. Both patients showed normal motor development through their childhood; Patient 1 ran fast and was involved in powerful heavy labor until the age of 40, and Patient 2 was in good health until 49, when they began to have progressive muscle weakness. They had no family history of neuromuscular diseases. On neurological examination, they had moderate muscle weakness and atrophy in their limb-girdle and paravertebral muscles. Because paravertebral and neck muscles were preferentially involved, they had difficulty in holding the head straight up. They stood in a lordotic posture. They had neither high-arched palate nor facio-skeletal abnormalities which were common findings in congenital nemaline myopathy. Serum enzymes derived from muscle were normal and needle electromyography showed myogenic and neurogenic changes in both patients. On CT scan of the skeletal muscles, the paravertebral muscles were markedly decreased in density suggesting advanced fat tissue replacement in large areas. In patient 2 who was in more advanced stage, the quadriceps femoris, hamstrings and soleus muscles also showed the similar CT findings. Light microscopic examination of biopsied biceps brachii (Patient 1) and quadriceps femoris (Patient 2) demonstrated abundant rod-like structures in the majority of type 1 fibers. In both patients, there was a marked variation in fiber size. Type 1 fibers were atrophic and type 2C fibers increased in number.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

[A case of Becker muscular dystrophy presenting cardiac failure as an initial symptom].

Was reported a 23-year-old man with Becker muscular dystrophy (BMD), manifesting heart failure as an initial symptom. He had admitted to a hospital because of his sudden exertional dyspnea due to dilated cardiomyopathy. Because of elevated serum CK level, he had admitted to our hospital for further clinical evaluation. His uncle and male cousin were affected by a mild progressive muscle weakness since second decades. Physically, his intelligence was slightly below the average (WAIS total IQ 71). There was a slight weakness in his pelvic and shoulder girdle muscles. Pseudohypertrophy was observed in calves and tongue. Serum CK level was markedly elevated to ten times of the upper normal limits. Both EMG and muscle biopsy examinations revealed mild myopathic changes. Electrocardiogram showed tall R waves in leads V1 and V2, abnormal Q waves in I, aVL, V5 and V6 and flattened T waves in V5 and V6. On immunostaining of the biopsied skeletal muscle, patchy appearance of dystrophin on the surface membrane of the fiber was detected, which is consistent with BMD. Myocardiac damages in BMD are not always related either to the duration or the severity of the skeletal muscle weakness, as shown in our present case. The possibility that subclinical BMD is one of causes for dilated cardiomyopathy always must be considered.

Adult↗

[Cardiomyopathy in Becker muscular dystrophy].

In 6 patients with dystrophin-verified Becker muscular dystrophy (BMD), 3 patients had dilated cardiomyopathy (DCM group). The other 3 patients (non-DCM group) also had ECG abnormalities including incomplete right bundle branch block, left ventricular enlargement and intraventricular conduction defect. Between DCM and non-DCM group, there was no prominent difference in ages at onset, mean duration and severity of muscular weakness. Serum CK levels, and molecular weight and amount of dystrophin also showed no significant difference between two groups. On reviewing 14 BMD patients, including 3 present patients with cardiomyopathy, the cardiac symptoms appeared from 4 to 41 years, averaging 17.1 years of age. The mean duration of muscle symptoms was 9 years, ranging from 0 to 33 years. There was no correlation between severity of muscle weakness and cardiomyopathy. Six patients died of heart failure and 3 received cardiac transplantation. Thus there was no characteristic clinical feature in BMD patients with cardiomyopathy except for very poor prognosis. Since the myocardial involvement is not related with clinical severity and duration of the disease, careful observation for cardiac function should be carried out in all BMD patients even in the early stage of muscle weakness.

Adolescent↗

[Muscle regeneration in mdx mouse, and a trial of normal myoblast transfer into regenerating dystrophic muscle].

The most ideal therapeutic trial on Duchenne muscular dystrophy (DMD) is a transfer of normal myoblasts into dystrophic muscle which has been attempted on animal models in several institutes. In the process of muscle regeneration, the transferred normal myoblasts are expected to incorporate into the regenerating fibers in host dystrophic mouse. To know the capacity of muscle regeneration in dystrophic muscle, we compared the regenerating process of the normal muscle with that of the dystrophic muscle after myonecrosis induced by 0.25% bupivacaine hydrochloride (BPVC) chronologically. In the present study, C57BL/10ScSn-mdx (mdx) mouse was used as an animal model of DMD and C57BL/10ScSn (B10) mouse as a control. There was no definite difference in the behavior of muscle fiber regeneration between normal and dystrophic muscles. The dystrophic muscle regenerated rapidly at the similar tempo to the normal as to their size and fiber type differentiation. The variation in fiber size diameter of dystrophic muscle, however, was more obvious than that of normal. To promote successful myoblast transfer from B10 mouse into dystrophic mdx mouse at higher ratio, cultured normal myoblasts were transferred into the regenerating dystrophic muscle on the first and the second day after myonecrosis induced by BPVC. Two weeks after the myoblast injection, the muscles were examined with immunohistochemical stain using anti dystrophin antibody. Although dystrophin-positive fibers appeared in dystrophic muscle, the positive fibers were unexpectedly small in number (3.86 +/- 1.50%).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

[A case of myopathy with ulcerative colitis].

A 41-year-old woman was admitted to a local hospital because of bloody diarrhea and diagnosed as having ulcerative colitis (UC). Despite prednisolone of 40 mg/day administration, her symptoms aggravated rapidly and she developed muscle weakness of lower limbs two weeks after steroid administration. On admission, she was bed-ridden and could not lift her knees and arms from bed. The serum CK level was increased slightly and total protein decreased markedly. She had moderate liver dysfunction, mild hyperthyroidism, mild glucose intolerance, and some results suggestive of immuno-deficiency including positive cold agglutinin and microsome tests, and positive antinuclear antibody. Her muscle biopsy showed both type 1 and 2 fiber atrophy and focal myofibrillar degeneration with autophagic phenomenon. There were a few fibers with nemaline bodies probably formed from marked degeneration of myofibrils. Although she had been on prednisolone for 2 weeks, the degenerative muscle pathology differed from that of steroid myopathy in which type 2 fiber atrophy is one of characteristic findings. Some additional factors including marked malnutrition, possible immuno-deficiency and hyperthyroidism should be considered for the pathogenesis of this particular myopathic changes. Since her general condition and muscle weakness gradually improved postoperatively, UC itself might have played an important role in inducing muscle symptoms.

Adult↗

[A female infant of mitochondrial myopathy with findings of active necrosis and regeneration of muscle fibers].

An 8 year-old female infant with the clinical and pathological characteristics of both progressive muscular dystrophy and mitochondrial myopathy was described. Her maternal cousin had clinical and pathological findings of Duchenne muscular dystrophy (DMD). Since the patient had markedly elevated serum CK and calf muscle hypertrophy, her muscle was biopsied and she was diagnosed as having female DMD at the age of 5 years. She had generalized tonic-clonic convulsions and alternate hemiconvulsions for recent 4 years which brought her our hospital. On admission, she had mild generalized muscle atrophy and weakness predominantly in the proximal limbs. The lactate and pyruvate levels in both serum and cerebrospinal fluid were elevated, but with no metabolic acidosis. Serum CK was elevated to 4464 IU/L. Brain CT and MRI showed the expanding arachnoid cyst in the left middle fossa of cranium. In the biopsied left biceps crachii muscle, in addition to numerous ragged-red fibers, there were active muscular fiber necrosis and regeneration and interstitial fibrosis similar to those seen in progressive muscular dystrophy. Biochemically, no decrease or defect in the respiratory chain enzymes was detected. On electron microscopy, a large number of fibers contained aggregates of giant mitochondria with proliferated complicated cristae. Scattered throughout were necrotic muscle fibers filled with phagocytes and regenerating fibers. This patient had the diagnostic features of mitochondrial encephalomyopathy and progressive muscular dystrophy. We supposed that the patient provided very interesting evidences to study the relationship between mitochondrial myopathy and progressive muscular dystrophy.

Child↗

Mosaic expression of dystrophin in symptomatic carriers of Duchenne's muscular dystrophy.

A deficiency of the protein dystrophin is known to be the cause of Duchenne's muscular dystrophy. To examine the expression of dystrophin in symptomatic female carriers of this X-linked recessive disorder, we performed immunohistochemical studies on muscle-biopsy specimens from three such carriers, using an antiserum raised against a synthetic peptide fragment of dystrophin. In all three carriers, most individual muscle fibers reacted either strongly or not at all to the antiserum for dystrophin; only 2 to 8 percent of fibers showed partial immunostaining. This mosaic staining pattern was present on both cross-sectional and longitudinal muscle specimens. Although the mosaic pattern was seen in all fiber types, more than 80 percent of type 2B and 2C fibers from two of the carriers did not react with the antiserum. Similar studies in nine normal subjects showed consistently strong staining of all muscle fibers. No muscle fibers from 31 patients with Duchenne's muscular dystrophy reacted with the antiserum. We conclude that symptomatic carriers of Duchenne's muscular dystrophy can be identified by a distinct mosaic pattern in the immunohistochemical staining of the surface membrane of skeletal-muscle specimens. This finding may have practical implications for genetic counseling, although it remains to be shown whether the same staining pattern will be found in muscle specimens from asymptomatic carriers of Duchenne's muscular dystrophy.

Adolescent↗

Vascular involvement in mitochondrial myopathy.

Electron microscopic examination of muscle specimens taken at biopsy in 6 patients with complex I deficiency and 1 patient with an unknown primary chemical defect who had the clinical characteristics of mitochondrial myopathy, encephalopathy, lactic acidosis, and stroke-like episodes (MELAS) revealed striking abnormalities in blood vessels in 5. Abnormalities consisted of an increased number of enlarged mitochondria with complicated cristae in the pericytes of capillaries, endothelial cells, and smooth muscle cells of the small arteries, including terminal arterioles and precapillary sphincters, predominantly in smooth muscle cells. On statistical analysis, the number of mitochondria and the ratio of mitochondrial area to the total area of the smooth muscle cells were increased approximately tenfold (p less than 0.001). Although stroke-like episodes were not present, similar mitochondrial abnormalities in blood vessels were found in 1 patient who had the encephalomyopathic form of complex IV deficiency and in 2 patients in whom the primary chemical defects could not be clearly defined. Such abnormalities in small arteries might be responsible for the occasional occurrence of transient cerebral ischemia causing stroke-like episodes and progressive mental deterioration.

Adolescent↗

Progression in nemaline myopathy.

Four of seven patients with nemaline myopathy had severe, rapidly progressing symptoms. These four showed an increase in acid phosphatase activity in muscle fibers demonstrated by histochemistry and cathepsin B&L activity by biochemical measurement. On electron microscopy, nemaline bodies, occasionally disorganized myofibrils and autophagic vacuoles containing sarcoplasmic debris and glycogen particles were seen. Focal myofibrillar degeneration, through an unknown pathogenetic mechanism, induces an increase in lysosomal enzymes in the skeletal muscles which may be closely correlated with a rapid aggravation of muscle weakness in nemaline myopathy.

Acid Phosphatase↗

Changes of subcellular localization of Thy-1 antigen during thymic myoid cell differentiation.

Using a quantitative enzyme immunoassay, Thy-1 antigen expressed by a rat myoid cell line R615B2 was detected mainly on the cell surface at a single cell stage, whereas at the stage of forming myotubes, Thy-1 was found predominantly in the cytoplasm. The muscle specific creatine kinase activity also increased in association with the shift of Thy-1 from the cell surface to the cytoplasm, suggesting biological significance of Thy-1 redistribution in muscle differentiation from single cells to multinucleated cells.

Animals↗