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Biomedical subjects

I Nonaka

Publications and source records attributed to I Nonaka.

At least 469 records · Page 26Linked to original sources

Duchenne muscular dystrophy: unusual activation of single fibers in vitro.

Single skinned fibers were prepared from muscle biopsies of patients with Duchenne muscular dystrophy (DMD) and other neuromuscular diseases. The activation of the contractile system by calcium or strontium ion and the function of the sarcoplasmic reticulum were studied. In many fibers of the biopsy specimens from patients with DMD, activation by strontium revealed a pattern intermediate between those shown by the usual type 1 and type 2 fibers. These fibers were generally of smaller diameter and produced less maximal tension than type 1 and 2 fibers. The study of muscle of newborn animals suggests that this unusual pattern of activation might reflect either arrested development or incomplete regeneration after muscle necrosis in the disease.

Adult↗

The significance of type 2C muscle fibers in Duchenne muscular dystrophy.

Undifferentiated type 2C fibers, which are dark on ATPase staining with both alkaline and acid preincubation, comprised on average 16.1% of the muscle fibers in 12 patients with Duchenne muscular dystrophy (DMD). Many of type 2C fibers had characteristics of regenerating fibers: basophilic cytoplasm, vesicular nuclei with occasional prominent nucleoli, high alkaline phosphatase and nonspecific esterase activity, and also high oxidative enzyme activity at the periphery of the fiber. A localized high acetylcholinesterase activity suggested the presence of a neuromuscular junction in some of the type 2C fibers. In serial sections, histochemical reactions characteristic of the type 2C fiber were present in segments of a single fiber, which in other parts was either a type 1 or a type 2 fiber. Since most of the opaque (hyaline, dark) fibers, which previously have been thought to be precursors of necrotic fibers, behaved as differentiated type 1 or type 2 fibers, the presence of type 2C fibers in DMD may not reflect "dedifferentiation" of fiber type, but rather indicate an active regenerating process. It remains unknown whether the type 2C fiber segments in DMD develop into fully differentiated functional fibers or remain as incompletely regenerated fibers.

Adenosine Triphosphatases↗

Myosin light chain components in single muscle fibers of Duchenne muscular dystrophy.

Single muscle fibers were prepared from biopsy specimens of Duchenne muscular dystrophy (DMD), normal, and neuromuscular disease controls. Single muscle cells were classified as type 1, type 2, or intermediate by the skinned fiber method. The intermediate fiber was most abundant in DMD, comprising 29% of fibers examined. The fiber type of single muscle fibers was contrasted to the composition of myosin light chain (MLC) components, which was analyzed by micro two-dimensional gel electrophoresis. In DMD, each of the components exhibited the same electrophoretic mobility as those in the controls. Type 1 fibers of DMD were more diverse in the composition of MLC than those of controls; 55% of type 1 fibers of DMD contained distinct fast-type MLC 3. Some intermediate fibers contained all five MLC components, but in others the composition was not different from usual type 1 or type 2 fibers. The diversity of MLC composition in DMD muscle cells might reflect the abundance of young muscle fibers in the tissue due to active muscle regeneration and/or retardation of maturation.

Adult↗

Immunohistochemical localization of AMP deaminase in rimmed vacuoles in human skeletal muscle.

High AMP deaminase reactivity was detected in the rimmed vacuoles in skeletal muscles in adult onset acid maltase deficiency and distal myopathy with rimmed vacuole formation histochemically as well as immunohistochemically. Acid phosphatase activity was positive but myosin ATPase activity was negative in the vacuoles. AMP deaminase found in rimmed vacuoles does not seem to be associated with myosin but is possibly bound to lysosomes or other related organelles in accordance with the proliferation of autophagic vacuoles.

AMP Deaminase↗

Demonstration of acid alpha-glucosidase in different types of Pompe disease by use of an immunochemical method.

The nature of mutant acid alpha-glucosidase (AAG) in muscle was studied in 6 patients with Pompe disease, consisting of 2 each of the infantile, childhood and adult types. Anti-human liver AAG rabbit antibody prepared in the present study was confirmed to be monospecific by immunodiffusion, immunotitration and immunohistochemical methods. It was found by the immunodiffusion and enzyme immunoassay methods using this antibody that the mutation produced a normal amount of enzyme protein but the latter was an inactive form, suggesting structural gene mutation in 5 of the 6 cases. In the remaining childhood type case there was no detectable amount of enzyme protein, suggesting that the mutation causes a reduction in the amount of the enzyme protein or synthesis of unstable enzyme protein. Similarly, the enzyme activity of AAG was markedly reduced in all patients, but that of neutral alpha-glucosidase was the least reduced in the adult type, medium in the childhood type, and the most reduced in the infantile type.

Adult↗

Idiopathic lactic acidemia with developmental delay and type 1 muscle fiber atrophy: report of two patients.

Two infants with generalized muscle hypotonia with mild muscle weakness and markedly delayed developmental milestones, had high lactate levels in serum and cerebrospinal fluid from early infancy. Biochemical and morphologic studies of biopsied muscles disclosed no abnormality except for type 1 fiber atrophy, which was quite different from patients with central nervous involvement with type 2 fiber atrophy. In both patients, the disease was not progressive and lactate levels gradually decreased. Although no metabolic defect was found, these patients probably shared common pathogenetic mechanism.

Acidosis, Lactic↗

Scoliosis associated with central core disease.

A 12-year-old Japanese girl who had progressive severe scoliosis but with minimal muscle weakness in the extremities was found to have central core disease. In her muscle biopsies obtained from the biceps brachii and paraspinous muscles, there was type 1 fiber atrophy and predominance, as is commonly seen in congenital myopathies, but the core structure was identified only in the former. To determine whether scoliosis is a prominent feature of this disease, we reviewed 10 patients with central core disease in our laboratory and found 6 ambulant patients who had mild-to-moderate scoliosis. Since kyphoscoliosis becomes prominent as muscle weakness progresses to loss of ambulation in most muscle diseases, this disproportionate spinal involvement in central core disease appears to be a striking feature. All patients with 'idiopathic' scoliosis deserve a careful neurological evaluation, even if they have minimal muscle symptoms in the extremities.

Adult↗

Early onset muscular dystrophy with autosomal dominant heredity. Report of a family and CT findings of skeletal muscle.

The clinical features and muscle pathology in a female infant and her mother with early onset and slowly progressive muscular dystrophy (MD), possibly transmitted through autosomal dominant inheritance, are described. The mother exhibited multiple joint contractures at birth. The daughter had mild proximal muscle weakness at 2 3/12 years old. The muscle biopsy specimens from both patients showed myopathic changes with evidence of fiber necrosis and regeneration. Computed tomographic (CT) findings of their skeletal muscles suggested that proximal muscles were involved at an early stage, with later gradual involvement of generalized muscles, without a characteristic selectivity pattern in thigh muscles. This may possibly be a clinically benign and distinct variant of MD with a slowly degenerating pattern of skeletal muscles on CT.

Adult↗

Progressive brainstem and white matter lesions in Kearns-Sayre syndrome: a case report.

We performed serial cranial MRI examinations on an 11-year-old boy with Kearns-Sayre syndrome. Proton density (PD)-, T2-weighted and T2-weighted fluid attenuated inversion recovery (FLAIR) sequences revealed progressive high signal intensity areas in the brainstem, globus pallidus, thalamus, and white matter of the cerebrum and cerebellum bilaterally. The probable gliotic lesions in the brainstem may be part of the neurogenic origin of the external ophthalmoplegia in addition to the primary defect of the extraocularmuscle in KSS.

Brain↗

A carrier of Duchenne muscular dystrophy with dilated cardiomyopathy but no skeletal muscle symptom.

A 29-year-old female developed dilated cardiomyopathy at 20 years of age but with no muscle symptoms. Her 2-year-old son with Duchenne muscular dystrophy (DMD)_had no demonstrable deletion in the dystrophin gene, but all fibers except for 5% 'revertant' fibers in a muscle biopsy specimen had no dystrophin. Both skeletal and cardiac muscle biopsy specimens from the mother showed a mosaic distribution of dystrophin-positive and -negative fibers, and so she was diagnosed as being a manifesting carrier of DMD. We conclude that, when one encounters a female patient with idiopathic cardiomyopathy with a high serum creatine kinase level, the suspicion of her being a manifesting DMD carrier should be ruled out.

Adult↗

Early onset distal muscular dystrophy.

A 14-year-old Chinese boy, who first became aware of muscle weakness in the lower limbs at 6 years of age, had progressive distal muscle weakness and atrophy, predominantly in the lower leg muscles. He exhibited reduced ankle dorsiflexion and tended to walk on his toes, showing preferential anterior tibial muscle involvement. Laboratory examination revealed a moderately elevated serum creatine kinase level of 905 IU/l. Computed tomographic scanning of muscle disclosed low density areas in the lower legs. A muscle biopsy specimen from the biceps brachii revealed mild dystrophic changes. We made a diagnosis of distal muscular dystrophy based on these findings, but could not classify it as one of the previously reported forms. The symptoms mimicked those of tibial muscular dystrophy, though the onset of the disease is far earlier than the previously described ones of distal muscular dystrophies. It remains unknown whether this patient has a new type of distal muscular dystrophy, or a variant form of the Miyoshi type or tibial muscular dystrophy.

Adolescent↗

Long-term therapy with cytochrome c, flavin mononucleotide and thiamine diphosphate for a patient with Kearns-Sayre syndrome.

Cardiocrome, containing cytochrome c, flavin mononucleotide and thiamine diphosphate, was administered intravenously for 22 months to a patient with Kearns-Sayre syndrome. This combined therapy alleviated the patient's easy fatigability, motor disability, corneal edema and chilblains, but was not effective for his ophthalmoplegia, blepharoptosis or hearing loss. Truncal ataxia, dysphagia and an atrioventricular block appeared even with this therapy. Although the abnormal distribution of cerebral blood flow demonstrated by single photon emission computed tomography was improved, serial cranial magnetic resonance imaging and electrophysiological examination revealed progressive changes. In conclusion, this therapy was favorably effective for impaired skeletal muscle function and corneal edema, but not for ocular movements, central nervous system symptoms or cardiac conduction abnormalities, because irreversible degeneration had probably occurred in these organs.

Cytochrome c Group↗

Merosin-negative non-Fukuyama-type congenital muscular dystrophy: a case report.

We report a female infant with non-Fukuyama-type congenital muscular dystrophy with merosin deficiency. She manifested marked hypotonia and muscle weakness from the neonatal period, with an elevated creatine kinase concentration. Her motor developmental milestones were markedly delayed; however, her intellectual development was normal. Although cranial computed tomography (CT) at 3 months of age was normal, subsequent CT at 16 months of age demonstrated diffuse, abnormal white matter lucencies. Muscle biopsy findings at 16 months of age were compatible with those of congenital muscular dystrophy. In addition, no muscle fibers were immunostained by the merosin antibody. The patient died of pneumonia at 23 months of age. These clinical symptoms and CT findings are similar to those described in patients with merosin-negative congenital muscular dystrophy in European countries.

Brain↗

A follow-up study of congenital non-progressive myopathies.

To determine the development and prognosis of patients with the moderate congenital form of congenital non-progressive myopathies (CNM), we investigated 55 patients with CNM by questionnaires. This patient group included 18 with nemaline myopathy, 11 with central core disease, 3 with myotubular myopathy, 15 with congenital fiber type disproportion and 3 with minicore disease. As to motor development, almost all patients had learned to walk alone by 3 years of age, averaging 2 2/12 years. Central nervous system involvement including mental retardation was seen in 24% of the patients, predominantly in patients with myopathy. The level of mental retardation was not related to the severity of muscle weakness. Patients with central core disease had a higher frequency of skeletal deformities. CNM were not necessarily benign in their prognosis as previously thought, but sometimes showed progressive deterioration leading to death. In 16% of patients, progressive deterioration in muscle strength and respiratory function became manifest after once the patient became ambulant. Even in the benign congenital form, seven of 55 patients died from respiratory or cardiac failures by 20 years of age. Therefore evaluation of cardiopulmonary function at regular intervals is important in the continuing care of patients with CNM.

Adolescent↗

Arthrogryposis multiplex congenita: histochemical study of biopsied muscles.

Morphometric analysis was performed after histochemical staining on 12 biopsied muscles of the affected limbs from 12 patients with arthrogryposis multiplex congenita. Except for one muscle, samples demonstrated variation in fiber size associated with abnormal fiber type distribution suggesting abnormal innervation: large groups of atrophic fibers in one muscle, either type 1 or 2 fiber predominance with occasional fiber type grouping in five, a complete lack of type 2 fibers in one, type one fiber atrophy in one, both type 2A and 2B fiber atrophy in two, and increased number of type 2C fibers in four. In most patients with arthrogryposis multiplex congenita, a defect in neural influence on the developing muscles may be responsible for the absence or maldevelopment of some muscle groups. Underdeveloped muscles are then assumed to induce imbalance of agonists and antagonists resulting in permanent contractures.

Adolescent↗

Nemaline myopathy: comparative muscle histochemistry in the severe neonatal, moderate congenital, and adult-onset forms.

A histochemical study of biopsied muscle specimens from patients with the 3 forms of nemaline myopathy (i.e., severe neonatal, moderate congenital, and adult-onset), classified on the basis of clinical symptoms, was conducted. A close relationship could not be found between the number of rods and the severity of weakness in any form. Type 1 fiber atrophy and predominance or type 2B fiber deficiency was the usual finding in all forms. In the moderate congenital form, type 1 fiber atrophy and predominance became more apparent in patients with a protracted course, suggesting that the histochemical abnormalities are progressive. The abnormal fiber type distribution is assumed to be related to the pathogenetic mechanism of nemaline myopathy in all forms. Because acid phosphatase activity was increased in muscle fibers of patients with rapid progression, an autodegenerative process inducing lysosomal enzyme activation may be responsible for the acute clinical progression and muscle fiber loss in this disorder.

Adolescent↗