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Query: UMLS:C0038454 (stroke)
 147,016 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The strongly succinate dehydrogenase-reactive blood vessels (SSV) are shown to have increased numbers of enlarged mitochondria in smooth muscle cells of the vessel wall on electron microscopy. They are seen in biopsied skeletal muscles from patients with mitochondrial myopathy, encephalopathy, lactic acidosis, and stroke-like episodes (MELAS) at high frequency. The present study was done to examine the incidence of SSV in biopsied muscles from various neuromuscular diseases. Among 107 patients with mitochondrial encephalomyopathies (MEM) including 50 with chronic progressive external ophthalmoplegia (CPEO), 7 with myoclonus epilepsy with ragged-red fibers (MERRF), and 50 with MELAS, SSV were seen in nearly a half of the patients, and comprised approximately 24% of small arteries. On the other hand, SSV in 100 patients with various neuromuscular diseases other than MEM were exceptional, and only one of 8 patients with myotonic dystrophy had SSV. These findings suggest that the SSV are induced by functional abnormality of mitochondria in smooth muscle cells, and that an identification of the SSV is an additional crucial evidence to make a pathological diagnosis of MEM.
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PMID:[Strongly succinate dehydrogenase-reactive blood vessels (SSV) in various neuromuscular diseases]. 142 48

Myocardial imaging with beta-methyl-p-(123I)-iodophenyl-pentadecanoic acid (123I-BMIPP), a new radiopharmaceutical designed to evaluate myocardial fatty acid metabolism, was performed in 7 patients with mitochondrial myopathy to detect their myocardial damages in comparison with 201Tl myocardial imaging. These patients were divided into 4 chronic progressive external ophthalmoplegia (CPEO) cases, 2 mitochondrial myopathy, encephalopathy, lactic acidosis, and stroke-like episodes (MELAS) cases and 1 myoclonus epilepsy with ragged-red fibers (MERRF). In visual assessment, we observed more myocardial segments with decreased uptake of 123I-BMIPP compared to 201Tl in MELAS cases than in CPEO cases. The mean myocardial uptake of 123I-BMIPP was higher than that of 201Tl in CPEO cases. On the other hand, in MELAS and MERRF cases, the mean myocardial uptake of 123I-BMIPP was lower than that of 201Tl. Abnormal findings suggesting myocardial damages were observed in echocardiogram and/or in electrocardiogram in MELAS and MERRF cases, while no such abnormal findings were observed in CPEO cases. Along with the previously reported experimental result that the impairment of rat myocardial mitochondria decreased myocardial uptake of 125I-BMIPP, these results suggest that 123I-BMIPP may be useful to detect myocardial damages in patients with mitochondrial myopathy.
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PMID:[Clinical study on myocardial imaging with beta-methyl-p-(123I)-iodophenyl-pentadecanoic acid in patients with mitochondrial myopathy]. 160 40

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

Peripheral neuropathy has attracted relatively little attention in mitochondrial myopathy. However, mitochondrial myopathies are clinically heterogeneous disorders that can affect multiple systems including peripheral nerves other than the skeletal muscle. In addition to the survey of the literature, we studied 6 cases of mitochondrial myopathy with peripheral neuropathy; 3 cases of oligo-systemic involvement confined mainly to skeletal muscles and peripheral nerves, and 3 cases of multi-systemic involvement diagnosed as myoclonus epilepsy with ragged-red fibers (MERRF) or mitochondrial myopathy, encephalopathy, lactic acidosis and stroke-like episodes (MELAS). This study suggests that peripheral neuropathy may be relatively common and has similar clinical and laboratory features in a broad spectrum of mitochondrial myopathies. The clinical manifestation is usually of mild sensorimotor neuropathy with frequent subclinical involvement. Sensory disturbances are more evident than manifestations of motor neuropathy which is usually subclinical. It is also noteworthy that there exist some cases of oligo-systemic involvement, which present with peripheral neuropathy as main clinical manifestations. Electrophysiological findings include decreased nerve conduction velocities and neuropathic electromyograms. Peripheral nerves show loss of myelinated fibers, particularly of large ones, and the remaining fibers have disproportionately thin myelin sheaths with or without onion-bulb formation. Thus the pathological process is axonal degeneration with demyelination resulting from involvement of both neurons (axons) and Schwann cells.
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PMID:Peripheral neuropathy of mitochondrial myopathies. 166 Jan 82

Defects in mitochondrial DNA (mtDNA) are associated with several different human diseases, including the mitochondrial encephalomyopathies. The mutations include deletions but also duplications and point mutations. Individuals with MELAS (mitochondrial myopathy, encephalopathy, lactic acidosis and stroke-like episodes) carry a common A-to-G substitution in a highly conserved portion of the gene for transfer RNA(Leu(UUR)). Although the MELAS mutation may be comparable to the defect in the tRNA(Lys) gene associated with MERRF (myoclonus epilepsy associated with ragged-red fibres), it is also embedded in the middle of a tridecamer sequence necessary for the formation of the 3' ends of 16S ribosomal RNA in vitro. We found that the MELAS mutation results in severe impairment of 16S rRNA transcription termination, which correlates with a reduced affinity of the partially purified termination protein for the MELAS template. This suggests that the molecular defect in MELAS is the inability to produce the correct type and quantity of rRNA relative to other mitochondrial gene products.
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PMID:Impairment of mitochondrial transcription termination by a point mutation associated with the MELAS subgroup of mitochondrial encephalomyopathies. 175 69

We describe a sporadic case of adult-onset, complex I deficiency mitochondrial encephalomyopathy (MEM), the clinical and pathological features of which failed to fit any of the known subgroups of MEM, such as Kearns-Sayre syndrome, mitochondrial encephalomyopathy, lactic acidosis and stroke-like episodes or myoclonus epilepsy with ragged-red fibers. Clinically, this patient had only progressive cerebellar ataxia, generalized muscle weakness and hearing loss. The principal finding at autopsy was degeneration of the olivo-ponto-cerebellar system. This case suggests that mitochondrial disease could underlie some cases of olivo-ponto-cerebellar atrophy.
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PMID:An autopsy case of mitochondrial encephalomyopathy with prominent degeneration in olivo-ponto-cerebellar system. 179 71

Several reports showed that abnormality of mitochondrial DNA (mt DNA) can be an etiology of cardiomyopathy in recent years. Cardiac involvement in mitochondrial disease other than Kearns-Sayre syndrome (KSS), however, has not been documented clearly. Therefore, cardiac involvement, abnormality of mt DNA and defects of the respiratory chain in mitochondrial disease were studied. Thirty-eight patients with mitochondrial disease were studied. The patients were consisted of 2 patients with KSS, 1 patient with probable KSS, 15 patients with ocular myopathy, 1 patient with myoclonus epilepsy with ragged-red fibers (MERRF), 6 patients with mitochondrial myopathy, encephalopathy, lactic acidosis, and stroke-like episodes (MELAS), 5 patients with undefined mitochondrial encephalomyopathy and 8 patients with mitochondrial myopathy. Cardiac involvement was evaluated by electrocardiogram (ECG), chest roentgenogram and echocardiogram. Abnormality of mt DNA was examined using Southern blotting and polymerase chain reaction method in 25 patients. Defects of the respiratory chain were examined in 27 patients. All of the KSS and probable KSS showed heart block, and 2 of the 3 patients showed abnormalities on echocardiogram. Five of the 15 patients with ocular myopathy showed abnormalities on EGG. Four of the 6 patients with MELAS showed abnormalities on ECG, 1 showed cardiomegaly, and 3 showed left ventricular hypertrophy on echocardiogram. Three of the 5 patients with undefined mitochondrial encephalomyopathy showed abnormalities on ECG, 2 showed cardiomegaly and 2 showed asymmetric septal hypertrophy and wall motion abnormalities on echocardiogram. Large-scale deletions of mt DNA were detected in all of the KSS and probable KSS, and 7 patients with ocular myopathy. Deletions of mt DNA in the skeletal and cardiac muscles were proved to be identical in a case of KSS. A point mutation in mt DNA was detected in 5 patients with MELAS. Defects of the respiratory chain were detected in 22 patients. In conclusion, cardiac involvement is frequently seen in mitochondrial disease. Abnormality of ECG, especially heart block, is characteristic of KSS. Left ventricular hypertrophy is characteristic of mitochondrial encephalomyopathy.
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PMID:[Cardiac involvement in mitochondrial disease: a clinical study of 38 patients]. 182 6

Mitochondrial respiratory chain function was investigated with polarographic and enzymatic studies, and correlated with immunoblot studies using a battery of probes against respiratory chain holocomplexes in a series of patients with myoclonus epilepsy and ragged red fibers (MERRF) syndrome. State III respiration rates in intact skeletal muscle mitochondria were normal in two cases, suggested site I deficiency in one case and a mid-respiratory defect in another. Immunological studies of complex I showed reduced levels of several subunits with the apparent absence of two bands (which at 45 and 42 kDa, coincide with the predicted electrophoretic mobility of the ND5 gene product) in one case. Complex I, III and IV composition was normal in the other three cases indicating no major disruption of complex assembly. A differing severity of skeletal muscle respiratory chain impairment in a group of unrelated patients with severe cerebral clinical involvement is best explained by uneven tissue distribution between brain and muscle of a heteroplasmic mtDNA mutation. The relationship between MERRF and mitochondrial encephalomyopathy, lactic acidosis and stroke-like episodes (MELAS) encephalopathies is reappraised by extension of this hypothesis.
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PMID:Functional respiratory chain studies in mitochondrial cytopathies. Support for mitochondrial DNA heteroplasmy in myoclonus epilepsy and ragged red fibers (MERRF) syndrome. 190 54

EEG was studied in 25 children and adolescents with mitochondrial encephalomyopathies, defined on the basis of clinical, biochemical and morphological criteria. Twenty cases conformed to well-known mitochondrial syndromes: Alpers syndrome [6], Leigh syndrome [2], MERRF (myoclonus epilepsy and ragged red fibers) syndrome [3], MELAS (mitochondrial myopathy, encephalopathy, lactic acidosis and stroke-like episodes) syndrome [5] and Kearns-Sayre syndrome [4]. Many patients were followed for several years with repeated EEG. In all, 112 EEG records were included in the study. A common feature of all the mitochondrial encephalomyopathic syndromes was slowing of the alpha rhythm. Epileptic discharges were seen in most syndromes. In spite of the small number of cases in each group, in Alpers, MERRF and MELAS syndromes we found sequential EEG patterns which seemed to be typical of the respective syndromes. In contrast, in Kearns-Sayre syndrome, a slow background rhythm was the only consistent finding. We conclude that EEG, especially repeated recordings, may be of help in the diagnostic evaluation of mitochondrial encephalomyopathies.
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PMID:EEG findings in children and adolescents with mitochondrial encephalomyopathies: a study of 25 cases. 192 9

The total sequence data for mitochondrial DNA (mtDNA) revealed distinct clustering of point mutations (pms) in mtDNA among one patient with myoclonus epilepsy with ragged-red fibers (MERRF), two patients with Parkinson's disease (PD), two patients with mitochondrial myopathy, encephalopathy, lactic acidosis, and stroke-like episodes (MELAS), and one patient with fatal infantile cardiomyopathy (FICM). Among 33 to 62 pms found in each patients, sequentially diverged five clusters of pms were detected and designated as C-1 to C-5. C-1, consisted of fourteen pms, existed in the MERRF patient, C-1 and C-2 (nine pms) in one PD patient, C-1 to C-3 (seven pms) in another PD patient, C-1 to C-4 (one pm) in one MELAS patient and C-1 to C-5 (three pms) in another MELAS patient and the FICM patient. From these clustering of pms, a phylogenetic tree of mitochondrial encephalomyopathies (ME) was constructed. This tree clearly indicated that the ME and PD patients are members of the same gene family, and the MELAS and FICM patients are each others' closest relative. Each patient's unique pms (14 to 28 pms) were detected and, from their characteristic features, the types of the mutations specific for the disease were classified as mit- + syn- for MERRF, mit- + p- for PD, and syn- + mit- for MELAS. An inverse relation was found between the total number of pms and life span of the MELAS and FICM patients.
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PMID:Distinct clustering of point mutations in mitochondrial DNA among patients with mitochondrial encephalomyopathies and with Parkinson's disease. 202 3


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