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Biomedical subjects

S Miyabayashi

Publications and source records attributed to S Miyabayashi.

At least 55 records · Page 3Linked to original sources
PubMed1990

Secondary amyloidosis in glycogen storage disease type Ib.

We observed the development of generalized amyloidosis in a girl with glycogen storage disease type Ib (GSD-Ib) who showed neutropenia, neutrophil dysfunction and recurrent infections. Renal and thyroid biopsies showed secondary amyloidosis, characterized by the presence of potassium permanganate sensitive Dylon positive deposits in glomeruli, renal vessels and thyroid interstitium. Immunohistochemistry showed that the deposits were composed of amyloid A (AA) protein. Possibly neutrophil abnormalities are involved in the pathogenesis of amyloidosis.

Amyloidosis↗
PubMed1990

Chronic pancreatitis in muscular cytochrome c oxidase deficiency.

Chronic pancreatitis is described in a 10-year-old boy with mitochondrial myopathy due to cytochrome c oxidase (complex IV) deficiency. There have been few reports of chronic pancreatitis associated with congenital metabolic diseases. Marked pancreatic calcifications and pseudocysts of the pancreatic head and tail were demonstrated by computed tomography of the abdomen and by endoscopic retrograde pancreatography, which were thought to be useful methods for morphological examination of the pancreas. In the patient, no possible etiological factors were identified, including anomalous pancreatobiliary ductal junction or biochemical abnormalities. The association between cytochrome c oxidase deficiency and chronic pancreatitis remains to be established.

Child↗
PubMed1989

Mutation of the E1 alpha subunit of the pyruvate dehydrogenase complex, in relation to heterogeneity.

Pyruvate dehydrogenase complex was studied using bio- and immunochemical methods in cultured cells derived from two patients with the severe type and one patient with the mild type of pyruvate dehydrogenase complex deficiency. In patients 1 and 2, enzyme activity was all but undetectable and associated with the absence of E1 alpha subunit of the complex. Patient 3 had a slightly reduced level of enzyme activity, and this was associated with a larger form of E1 alpha subunit. The amount and size of E1 alpha mRNA in the three patients was similar to that of control samples. Thus, the severity of E1 alpha deficiency in these three patients is likely to depend on the type of mutation in the pyruvate dehydrogenase E1 alpha subunit and the synthesis and degradation rate of the subunit.

Cells, Cultured↗
PubMed1988

Defects in muscle fiber growth in fatal infantile cytochrome c oxidase deficiency.

In addition to numerous ragged-red fibers in the muscle from a female infant with fetal infantile cytochrome c oxidase deficiency, the muscle fibers were small in caliber with electron microscopic characteristics of immaturity; the satellite cells were significantly increased in number to 31.3% as compared with those in controls, 8.4 +/- 1.6% (p less than 0.001). In the culture system, the biopsied muscle showed markedly reduced growth despite the presence of numerous satellite cells which are known to act as myoblasts in muscle regeneration, and formed fewer numbers of myotubes containing poorly organized myofibrils and mitochondria with no cytochrome c oxidase activity. A defect in myogenesis and a paucity in repair process in severe form may account for the progressive course and a fatal outcome.

Biopsy↗
PubMed1988

Extensive defects of mitochondrial electron-transfer chain in muscular cytochrome c oxidase deficiency.

This study was undertaken to estimate the extent of molecular defects in the mitochondrial electron-transfer chain of a patient with mitochondrial myopathy. Biochemical and immunochemical studies were performed on the skeletal muscle mitochondria. Spectrophotometry and enzyme activity measurements localized a definite defect at the segment of cytochrome c oxidase (complex IV) of the electron-transfer chain. Immunoblotting and immunoprecipitation studies using the anti-complex IV antibody revealed that the contents of subunits 1, 4, 5, 6, and 7 of complex IV were markedly diminished and that subunit 2 was almost absent. Immunohistochemistry of the muscle tissue revealed a considerable accumulation of immunoreactive materials of complex IV in the ragged-red fibers. The immunoblots using the anti-NADH-ubiquinone oxidoreductase antibody demonstrated that the contents of NADH-ubiquinone oxidoreductase subunits were 47% of control and that the contents of three subunits were considerably decreased. The contents of ubiquinol-cytochrome c oxidoreductase subunits were also somewhat low (77% of control) and one of the minor contaminants detected in the control was completely absent. High-resolution one-dimensional sodium dodecyl sulfate-urea-gel electrophoresis disclosed that six additional unidentified polypeptides in the control were markedly diminished or completely missing. These results demonstrate that the molecular defects in the mitochondrial electron-transfer chain are more extensive than would be expected from either spectral analysis or enzyme activity measurements alone, and involve not only complex IV but also NADH-ubiquinone oxidoreductase and ubiquinol-cytochrome c oxidoreductase and several unidentified mitochondrial proteins.

Adult↗
PubMed1987

Cerebral glucose utilization in pediatric neurological disorders determined by positron emission tomography.

We measured local cerebral glucose utilization in 19 patients with Lennox-Gastaut syndrome (LG), partial seizures (PS), atypical and classical phenylketonuria (PKU), Leigh disease, and subacute sclerosing panencephalitis (SSPE), using positron emission tomography (PET). The mean values of regional glucose utilization in interictal scans of LG were significantly reduced in all brain regions when compared with that of PS (P less than 0.005). PET studies of glucose utilization in LG revealed more widespread hypometabolism than in PS. Two siblings with dihydropteridine reductase deficiency, a patient with classical PKU, and a boy with cytochrome c oxidase deficiency showed reduced glucose utilization in the caudate and putamen. A marked decrease in glucose utilization was found in the cortical gray matter of a patient with rapidly progressive SSPE, despite relatively preserved utilization in the caudate and putamen. The PET study of a patient with slowly progressive SSPE revealed patterns and values of glucose utilization similar to those of the control. Thus, PET provided a useful clue toward understanding brain dysfunction in LG, PS, PKU, Leigh disease, and SSPE.

Adolescent↗
PubMed1987

Regional cerebral metabolic rate for glucose in subacute sclerosing panencephalitis.

Regional cerebral metabolic rates for glucose (rCMRglc) were measured in two cases of subacute sclerosing panencephalitis (SSPE) with different clinical courses. A marked decrease in rCMRglc was found in the cortical gray matter of a patient with rapidly developing SSPE (3.6-4.2 mg/100 g brain tissue per min). However, the rCMRglc was preserved in the caudate and lenticular nuclei of the patient (7.7 mg/100 g per min). The rCMRglc in a patient with slowly developing SSPE revealed patterns and values similar to those of the control. The rCMRglc correlated better with the neurological and psychological status of SSPE.

Adolescent↗
PubMed1987

Regional cerebral metabolic rate for glucose and cerebrospinal fluid monoamine metabolites in subacute sclerosing panencephalitis.

Regional cerebral metabolic rate for glucose (rCMRglu) and cerebrospinal fluid monoamine metabolites were measured in two cases of subacute sclerosing panencephalitis (SSPE) with different clinical courses. A marked decrease in rCMRglu was found in the cortical gray matter of a patient with rapidly developing SSPE (3.6-4.2 mg/100 g brain tissue/min). However, the rCMRglu was preserved in the caudate and lenticular nuclei of the patient (7.7 mg/100 g/min). The rCMRglu in a patient with slowly developing SSPE revealed patterns and values similar to those of the control. Cerebrospinal fluid monoamine metabolites; homovanilic acid and 5-hydroxyindoleacetic acid, were decreased in both rapidly and slowly developing SSPE. These data indicated that rCMRglu correlated better with the neurological and psychological status and that dopaminergic and serotonergic abnormalities have been implicated in pathophysiology of SSPE.

Adolescent↗
PubMed1986

Ocular findings in childhood lactic acidosis.

We examined ophthalmologically nine children with lactic acidosis. All showed abnormal ocular findings. Optic atrophy was present in six patients, nystagmus in three, blepharoptosis in one, cataract in one, and limitation on abduction in one. We believe that optic atrophy is the most frequent ocular finding and that nystagmus and ophthalmoplegia are common associations in patients with childhood lactic acidosis.

Acidosis, Lactic↗