Search PubMed⌕ Search

Biomedical subjects

S Miyabayashi

Publications and source records attributed to S Miyabayashi.

64 records · Page 4Linked to original sources
PubMed1985

Biochemical study in 28 children with lactic acidosis, in relation to Leigh's encephalomyelopathy.

An enzymatic study of cultured skin fibroblasts was made in 28 patients with lactic acidosis. In three of these patients a diagnosis of Leigh's encephalomyelopathy was established from autopsy findings. Pyruvate decarboxylase (PDC) deficiency was found in four patients. In two of them, in whom Leigh's encephalomyelopathy was proved by autopsy, PDC activity was lower than 10% of the normal. The other two living patients, who showed 22%-25% of the normal activity, had clinical symptoms and courses different from Leigh's disease. These findings suggest that the patients with severe PDC deficiency develop Leigh's disease but those with mild deficiency may not. A deficiency of cytochrome c oxidase was found in two siblings. One of them, who was diagnosed as having Leigh's encephalomyelopathy by postmortem examination, showed a reduction of cytochrome c oxidase in the liver and brain. In the other sibling, who is living, the reduction of cytochrome c oxidase was demonstrated in the cultured skin fibroblasts and biopsied muscle. In an electron-microscopic study of biopsied muscle, two patients with mitochondrial myopathy were found. Their fundamental enzymatic defects were unclear. In two patients, in whom Leigh's disease was suspected following a brain CT, the production of 14CO2 from [3-14C] pyruvate was found to be low; suggesting a reduced activity of the TCA cycle. In another 18 patients, the fundamental defect was not clear.

Acidosis↗
PubMed1984

Cytochrome C oxidase deficiency in two siblings with Leigh encephalomyelopathy.

Two siblings with cytochrome c oxidase deficiency are described. One of them died of subacute necrotizing encephalomyelopathy which was proven by autopsy. The other was also suspected of having Leigh encephalomyelopathy by the findings on brain CT scans. The former, a younger brother, was in good health until the age of 10 months when progressive dysphagia, muscular hypotonia and abnormal eye movements became apparent. Six months later he suddenly died due to respiratory insufficiency. The latter, an elder brother, started to show nystagmus, abnormal eye movements and ataxia at the age of 5 years. A deficiency of cytochrome c oxidase in the younger brother was demonstrated in autopsied liver and brain, while such a deficiency in the elder brother was shown in biopsied peripheral muscle tissue and in cultured skin fibroblasts. Both patients showed a marked heat lability of cytochrome c oxidase. These results suggest that the biochemical defect observed in the siblings is due to a genetic defect. This seems to be the first case of a generalized defect in cytochrome c oxidase.

Brain↗
PubMed1982

Lymphoblasts and diagnosis of pyruvate carboxylase deficiency.

Pyruvate carboxylase activity was measured in phytohemagglutinin-transformed lymphocytes (i.e. lymphoblasts). Mean value +/- S.D. for 10 controls was 259 +/- 38 pmoles/min per mg protein. It was about 7 times higher than that of peripheral leukocytes and a half of cultured skin fibroblasts with similar techniques. Deficient pyruvate carboxylase activity less than 6 pmoles/min per mg protein was demonstrated in the lymphoblasts from a patient with biotin-dependent multiple carboxylase deficiency. It is suggested that lymphoblasts may allow more reliable and ready diagnosis of patients with pyruvate carboxylase deficiency.

Adult↗
PubMed1982

Pyruvate decarboxylase deficiency in a patient with Leigh's encephalomyelopathy.

A 23-month-old boy with progressive muscular hypotonia and mental and motor deterioration was described. Four days after the admission he had a respiratory arrest and required the care in a respirator thereafter. Laboratory examinations showed metabolic acidosis and high levels of pyruvate, lactate and alanine in blood and cerebrospinal fluid. Oral administration of thiamine-HCl and lipoic acid was noneffective and he died 7 months after the admission. Autopsy findings were compatible with subacute necrotizing encephalomyelopathy (Leigh's disease). The activity of pyruvate decarboxylase in autopsy samples was not detectable and that in fibroblasts was 9% of that in control cell lines. The present study confirmed that pyruvate decarboxylase deficiency is one of the causes of Leigh's disease.

Brain↗
PubMedDate not supplied

Cytochrome C oxidase-deficient mitochondria in mitochondrial myopathy.

Electron microscopic cytochemistry was used to evaluate the behavior of cytochrome c oxidase (COX) in cultured skin fibroblasts from 4 patients with decreased COX activity (Leigh encephalopathy, fatal infantile COX deficiency). In patients with Leigh encephalopathy, all mitochondria reacted to COX staining either equivocally or negatively, indicating that all mitochondria were abnormal in these patients. In 1 patient with fatal infantile COX deficiency, intercellular heterogeneity of mitochondria was observed by COX staining. In another patient with fatal infantile COX deficiency, intracellular heterogeneity of mitochondria was observed. Patients with Leigh encephalopathy appeared to have a different type of mitochondrial COX deficiency than those with fatal infantile COX deficiency. Our result suggest that these 2 diseases may result from different genetic mechanisms.

Acidosis, Lactic↗