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Query: UMLS:C0085584 (encephalopathy)
 18,178 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Inorganic lead, added to the diet of suckling rat in high doses, produces an encephalopathy similar to that seen in the immature human. Pathologic changes of edema and hemorrhage are seen earliest and are most prominent in the cerebellum. In this study, we measured respiration in cerebral hemisphere and cerebellar mitochondria isolated from led-fed and age-matched normal rat pups. Lactating mothers were begun on ad libitum feedins containing 4% lead carbonate when their pups were 2 weeks old. Mitochondria were isolated by differential centrifugation. Oxygen consumption was measured polarographically, NAD-linked respiration was measured with oxidation of the substrate pair, glutamate and malate. Cytochrome oxidase (cytochrome c oxidase, EC. 1.9.3.1) activity was measured in the presence of tetramethyl-p-phenylenediamine dihydrochloride (TMPD) and ascorbate. Within 2 days of starting lead feedings, rat pups showed a significant loss in body weight (P less than 0.02) and, after 1 week, a significant loss in cerebral hemisphere wet weight (P less than 0.01) compared with controls. Overt encephalopathy appeared in pups from two of nine litters receiving lead feedings for 1 week and in half of the litters after 2 weeks of feedings. None of the lead-fed mothers developed encephalopathic signs. With oxidation of the NAD-linked substrate pair, there was a progressive decrease, relative to controls, in ADP/O ratios in both cerebellar and cerebral mitochondria from lead-fed animals. After 2 weeks these differences were significant in mitochondria from both regions (cerebellum, P less than 0.02; cerebrum, P less than 0.005). Respiratory control ratios were significantly lower in cerebellar mitochondria from lead-fed rats within 2 days of beginning feedings (P less than 0.02) and in mitochondria from both regions after 2 weeks of lead feedings (cerebellum, P less than 0.01; cerebrum, P less than 0.05). The decrease in control ratios in cerebellar mitochondria from animals receivint lead feedings for 1 week or less was due to a small decrease in state 3 respiration and a large, but inconsistent, increase in state 4 respiration. The decrease in control ratios in both cerebellar and cerebral hemisphere mitochondria after 2 weeks of lead feedings was due to a marked inhibition of state 3 respiration, relative to controls (cerebellum, P less than 0.01; cerebral hemisphers, P less than 0.05). In cerebellar mitochondria from lead-fed animals, cytochrome oxidase activity showed similar changes compared with controls: a highly significant (P less than 0.001) increase within 2 days of beginning feedings and a significant (P less than 0.01) decrease after 2 weeks of feedings.
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PMID:Early effects of inorganic lead on immature rat brain mitochondrial respiration. 17 53

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.
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PMID:Cytochrome C oxidase-deficient mitochondria in mitochondrial myopathy. 131 74

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.
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PMID:Leigh encephalopathy: histologic and biochemical analyses of muscle biopsies. 132 89

Vascular involvement in biopsied muscle specimens from 11 patients with chronic progressive external ophthalmoplegia (CPEO) with ragged-red fibers (RRF) was studied. Almost none of 69 intramuscular arteries examined were strongly stained with succinate dehydrogenase (SDH) except one patient who had 2 SSV (strongly SDH-reactive blood vessels) in his muscle biopsy. Although RRF and focal cytochrome c oxidase (CCO) deficiency in muscle fibers were the common histochemical changes in muscle biopsy specimens from CPEO patients, all mitochondria in both endothelial and smooth muscle cells of the arteries had normal morphology except for the two SSV and all mitochondria in the blood vessels had normal CCO activity by electron cytochemistry. The findings obtained from the present study were quite different from those in mitochondrial myopathy, encephalopathy, lactic acidosis, and stroke-like episodes (MELAS), and myoclonus epilepsy associated with ragged-red fibers (MERRF) in which the striking vascular involvement with SSV is the most common and major abnormality in muscle biopsy specimens. To study vascular involvement in mitochondrial encephalomyopathies is the one of very important clues to understand the pathophysiology of phenotypic expressions in mitochondrial encephalomyopathies.
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PMID:[Vascular pathology in chronic progressive external ophthalmoplegia with ragged-red fibers]. 161 73

To determine whether a mitochondrial mRNA deficiency exists in mitochondrial myopathies, muscle biopsies from a patient with chronic progressive external ophthalmoplegia (CPEO) and a patient with mitochondrial myopathy, encephalopathy, lactic acidosis and stroke-like episodes (MELAS) were studied using in situ hybridization. Histochemistry and immunohistochemistry were performed along with hybridization. Hybridization reactions were widely distributed over the sarcoplasm of all muscle fibers in the patient with MELAS. In the patient with CPEO, 80% of the fibers showed a marked decrease in density of autoradiographic grains. This marked decrease corresponded to the histochemical and immunohistochemical findings of a very weak staining of cytochrome c oxidase (CCO). The isotope-labeled cDNA probe used in in situ hybridization in this study complements a part of subunit I of CCO and a part of subunit II of complex I in the mitochondrial gene. Our results suggest a defect in the mRNA in this CPEO patient.
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PMID:In situ hybridization of muscle mitochondrial mRNA in mitochondrial myopathies. 170 73

We report a 14-year-old boy with mitochondrial myopathy, encephalopathy, lactic acidosis, and strokelike episodes (MELAS) who presented repeated episodes of abdominal pain and vomiting since the age of 8 years. In addition, he developed strokelike episodes with myoclonic seizures and transient hemiplegia on three occasions. At the age of 14-1/12-years, he also developed epilepsia partialis continua persisting for 10 days, which was associated with myoclonic seizures synchronized with spike discharges at the right central area. Laboratory examination disclosed increased levels of lactate and pyruvate in serum and CSF and low density areas in the bilateral temporal regions on CT scan. Muscle biopsy showed scattered ragged-red fibers. The enzyme activities (pyruvate dehydrogenase complex, pyruvate carboxylase, phosphoenol pyruvate carboxykinase, and cytochrome c oxidase) and the rates of decarboxylation of [3-14C]pyruvate in cultured skin fibroblasts were within normal ranges.
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PMID:[A case with MELAS associated with epilepsia partialis continua]. 189 96

Two 30-year old twins, one male, the other female, were followed up for 20 years for predominantly proximal muscular deficit without increase of muscle enzymes. The lactic acid level was elevated at rest and further increased during exercise. Muscle biopsy revealed mitochondrial abnormalities. Encephalopathy was also present. The female patient had been treated, at the age of 10 years, for myoclonic attacks which regressed when she was over 18 years. None of the two patients had dementia. CT and MRI showed very extensive and symmetrical lesions of the white matter which did not involve the basal ganglia. These two cases are interesting on three scores: (1) clinically, the woman exhibited symptoms of the MELAS syndrome (without cerebral vascular accidents) and symptoms of the MERRF syndrome, which suggests the existence of borderline cases; (2) genetically, our cases were in favour of a so-called "maternal" heredity (boys are affected in all cases): here both sexes were involved but the phenotype varied; (3) biochemically, we found no enzyme activity deficit likely to explain the clinical features. The significance of a selective increase of cytochrome c oxidase in both mother and daughter is unclear.
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PMID:[Mitochondrial myopathy and leukoencephalopathy in twins of different sexes]. 196 56

An 18-year-old male with mitochondrial myopathy, encephalopathy and lactic acidosis was studied by electromyography (EMG) along with histological and biochemical studies on his biopsied muscle. Mitochondrial cytochrome c oxidase deficiency with a decrease in the amounts of the subunits 2, 6, and 7 was discovered. Although no apparent symptoms of peripheral neuropathy were present, EMG revealed high-amplitude motor unit action potentials with a reduced interference pattern and the histochemical study revealed fiber type grouping without grouped atrophy. These findings indicated lower motor neuron damage, probably due to the mitochondrial disorder, followed by reinnervation. Coenzyme Q10 administration was effective in reducing both the lactate and pyruvate levels and for recovering the muscle atrophy.
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PMID:A case of mitochondrial myopathy, encephalopathy and lactic acidosis due to cytochrome c oxidase deficiency with neurogenic muscular changes. 215 48

Electron microscopic histochemistry was applied to the study of cytochrome c oxidase activity in each mitochondrion of biopsied muscles from four patients with mitochondrial myopathy [one case of fatal infantile mitochondrial myopathy, one case of myoclonus epilepsy associated with ragged-red fibers (MERRF), and two cases of mitochondrial myopathy, encephalopathy, lactic acidosis and stroke-like episodes (MELAS)]. In the patient with fatal infantile mitochondrial myopathy, intercellular heterogeneity of mitochondria was recognized. In the three patients with either MERRF or MELAS, cytochrome c oxidase activity was segmentally changed from positive to negative within single muscle fibers. In the two patients with MELAS, small groups of positive-stained mitochondria were located among negative-stained mitochondria in the negative segment of a few muscle fibers. These findings revealed that there were heterogeneous populations of normal and abnormal mitochondria intracellularly or intercellularly within the muscles of these patients.
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PMID:Mosaicism of mitochondria in mitochondrial myopathy: an electronmicroscopic analysis of cytochrome c oxidase. 217 7

Two patients with mitochondrial myopathy, encephalopathy, lactic acidosis and strokelike episodes (MELAS) in one family are reported. Pathological examination of case 1 showed ragged-red fibers, with 7% of the fibers being unstained by cytochrome c oxidase stain, peripheral nerve damage, multiple areas of softening in the cerebrum and midbrain, and spongy changes in the cerebrum, optic nerve and pons. Electron microscopic examination revealed abnormal accumulations of mitochondria in the skeletal muscle, smooth muscle and cardiac muscle. The activity of cytochrome c oxidase in the brain and liver showed a tendency to decrease. In case 2 (maternal aunt of case 1), muscular weakness and peripheral nerve damage improved by treatment with coenzyme Q10. By adding idebenone to the coenzyme Q10 therapy, the EEG and Wechsler's Adult Intelligence Scale (WAIS) improved. Furthermore, in the cerebral spinal fluid (CSF), the protein, lactate, and pyruvate decreased, and the monoamines and monoamine metabolites increased.
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PMID:Mitochondrial encephalomyopathy (MELAS): pathological study and successful therapy with coenzyme Q10 and idebenone. 273 8


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