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Biomedical subjects

I Nonaka

Publications and source records attributed to I Nonaka.

477 records · Page 27Linked to original sources
PubMedDate not supplied

Congenital fiber type disproportion myopathy in Lowe syndrome.

Two brothers with the typical clinical features of oculocerebro-renal syndrome of Lowe exhibited delays in developmental milestones, muscular weakness and hypotonia, and high serum creatine kinase activity. The biopsied muscle revealed selective type 1 fiber atrophy and mild type 1 fiber predominance, similar to that observed in congenital fiber type disproportion myopathy. The abnormal fiber type distribution may be responsible for the common finding of muscle hypotonia in this syndrome.

Atrophy↗
PubMedDate not supplied

Infantile cytochrome c oxidase deficiency with neonatal death.

A newborn male presented with severe respiratory insufficiency, generalized muscle weakness, and lactic acidemia. Immediately after admission, he was placed on a respirator because of respiratory arrest. He deteriorated rapidly and died 75 hours after birth. There was notable variation in fiber size and an increased number of type 2C fibers in the quadriceps femoris muscle obtained at autopsy; however, no ragged-red fibers were observed with modified Gomori trichrome staining. Markedly decreased cytochrome c oxidase activity was demonstrated in skeletal muscle by biochemical and histochemical studies, while cardiac muscle demonstrated normal cytochrome c oxidase activity. Mitochondrial myopathy should be considered in the differential diagnosis of patients with neonatal respiratory distress syndrome.

Cytochrome-c Oxidase Deficiency↗
PubMedDate not supplied

Respiratory muscle involvement in nemaline myopathy.

A boy who had experienced generalized muscle weakness and hypotonia since early infancy was diagnosed as having nemaline myopathy on the basis of muscle biopsy at 3 years of age. At 8 years of age, he developed severe respiratory failure and required respiratory support during sleep. Because of recurrent pneumothorax, he underwent thoracic surgery, at which time biopsy specimens were obtained from the respiratory and truncal muscles. The histologic findings of the respiratory muscles included marked variation in fiber size with a notable increase in fibrous tissue, type 2 fiber deficiency, elevated acid phosphatase activity, and a disorganized intermyofibrillar network. The findings from the truncal muscles were similar to those of the biceps brachii muscle: little variation in fiber size, numerous nemaline bodies in all fibers, and type 1 fiber predominance. The preferential damage to the respiratory muscles was probably responsible for the sudden onset of severe respiratory failure.

Biopsy↗
PubMedDate not supplied

Cytochrome c oxidase deficiency with acute onset and rapid recovery.

A 7-year-old girl with cytochrome c oxidase deficiency who had no neurologic deficits in infancy suddenly developed ophthalmoplegia, ptosis, and respiratory arrest. She recovered almost completely 80 days after onset, suggesting that acute onset and rapid remission are observed in patients with cytochrome c oxidase deficiency. It is also possible that early initiation of therapy in cytochrome c oxidase deficiency with coenzyme Q10 may hasten and enhance the therapeutic effect.

Acute Disease↗
PubMedDate not supplied

Leigh encephalopathy: histologic and biochemical analyses of muscle biopsies.

To elucidate the pathogenesis of Leigh encephalopathy, histologic, biochemical, and mitochondrial DNA analyses were performed on biopsied muscles from 33 patients with the clinical characteristics of this disorder. On muscle histochemistry, cytochrome c oxidase activity was decreased or absent in 7 patients (21%), although none had ragged-red fibers. In 2 patients with cytochrome c oxidase deficiency, staining for this enzyme was poor in the muscle fibers and fibroblasts but was normal in the arterial wall, indicating tissue-specific involvement. Ten patients (30%) had biochemical defects, including 2 with pyruvate dehydrogenase complex, 4 with cytochrome c oxidase, 1 with NADH-cytochrome c reductase (complex I), and 3 with multiple complex deficiencies. None of the 28 patients in whom muscle mitochondrial (mt)DNA was analyzed had DNA deletions or point mutation at nucleotide positions 3,243 or 8,344. These results indicate that the underlying defect in Leigh encephalopathy is heterogeneous because only 30% of patients had enzyme defects demonstrable in muscle biopsy material.

Child↗
PubMedDate not supplied

Fatal infantile mitochondrial encephalomyopathy with complex I and IV deficiencies.

A 4-month-old male infant had a fatal infantile mitochondrial disease associated with cardiomyopathy. He had elevated lactate concentrations in blood and cerebrospinal fluid and an increased lactate/pyruvate ratio. Histochemical analysis of muscle biopsy revealed several ragged-red fibers on modified Gomori trichrome stain and mildly decreased cytochrome c oxidase (complex IV) activity. Complex I and IV activities of the respiratory chain in muscle were decreased to about 35% of normal values biochemically; subunits of the two complexes were decreased nonselectively on immunoblotting. Mitochondrial DNA analysis failed to detect any mutation. Complex I and IV deficiencies should be considered as one of the causes of fatal infantile mitochondrial disease.

Acidosis, Lactic↗
PubMedDate not supplied

Myopathy with abnormal distribution of dystrophin, growth retardation, mental retardation, and hypospadia.

A 9-year-old boy with severe growth retardation, mild mental retardation, and hypospadia had a high serum CK level without muscle weakness and atrophy. Muscle biopsy revealed a moderate variation in fiber size with a few necrotic and scattered regenerating fibers. Although muscle membranes were clearly stained by immunostaining with antibody to dystrophin, N-terminal region (2-5E2), fibers in groups revealed striking, intense staining with the other antibody, C-terminal region (4C5), suggesting some aberration of the dystrophin gene near the C-terminal area. His unique clinical features, as well as myopathy, are reported, although further study is necessary to clarify the relationship between the anomalous conditions and dystrophin abnormalities.

Adrenal Insufficiency↗
PubMedDate not supplied

The role of the dystrophin-glycoprotein complex in the molecular pathogenesis of muscular dystrophies.

The dystrophin-glycoprotein complex is considered to be a major trans-sarcolemmal structure which provides a linkage between the subsarcolemmal actin cytoskeleton and the extracellular matrix component laminin. Recently, deficiency of the dystrophin-associated proteins has been shown to play an important role in the molecular pathogenesis of several forms of muscular dystrophy. These include Duchenne muscular dystrophy (DMD), symptomatic DMD carriers, Becker muscular dystrophy and severe childhood autosomal recessive muscular dystrophy with DMD-like phenotype prevalent in North Africa. In Fukuyama-type congenital muscular dystrophy (FCMD), the finding of abnormal expression of the dystrophin-associated proteins may provide a clue to its molecular pathogenesis. These recent findings indicate that the linkage between the subsarcolemmal cytoskeleton and extracellular matrix via the dystrophin-glycoprotein complex is critical for maintaining the integrity of muscle cell function.

Child↗