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

The MELAS syndrome (mitochondrial myopathy, encephalopathy, lactic acidosis, and stroke-like episodes) can be difficult to identify. We report MRI abnormalities that we believe are specific to this disorder in three patients with complete or partial MELAS syndrome. The patients all showed an unusual pattern on T2-weighted MRI with multifocal areas of hyperintense signal confined to the cortex of the cerebrum, cerebellum, and adjacent white matter. Some images suggested selective cortical involvement of deeper layers only. Deep white matter was relatively spared, distinguishing this from usual cerebrovascular disease or the edema after status epilepticus. Specificity of these findings is further suggested by a good correlation of these findings with the previously described unique postmortem brain pathology of MELAS.
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PMID:Magnetic resonance imaging shows specific abnormalities in the MELAS syndrome. 206 32

A 12 year old girl with mitochondrial myopathy, encephalopathy, lactic acidosis and stroke like episodes (MELAS) is reported. After a normal childhood, at 9 years of age she developed generalized and hemilateralized seizures. Posteriorly, these episodes became more frequent and were accompanied by headache, homonimous hemianopsia, ataxia, vomiting, photophobia, left hemiparesis, slurred speech and even convulsive status. Laboratory tests evidenced lactic acidosis, brain lucencies at CT Scan and ragged skeletal muscle fibers at muscle biopsy.
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PMID:[Mitochondrial encephalomyopathy, lactic acidosis and features of cerebrovascular disorders]. 207 86

Mitochondrial encephalomyopathies are usually divided into three distinct clinical subgroups: (1) mitochondrial myopathy, encephalopathy, lactic acidosis and stroke-like episodes (MELAS); (2) myoclonus epilepsy associated with ragged-red fibres (MERRF); and (3) chronic progressive external ophthalmoplegia (CPEO) including Kearns-Sayre syndrome. Large deletions of human mitochondrial DNA and a transition mutation at the mitochondrial transfer RNALys gene give rise to CPEO including Kearns-Sayre syndrome and MERRF, respectively. Here we report an A-to-G transition mutation at nucleotide pair 3,243 in the dihydrouridine loop of mitochondrial tRNA(Leu)(UUR) that is specific to patients with MELAS. Because this mutation creates an ApaI restriction site, we could perform a simple molecular diagnostic test for the disease. The mutation was present in 26 out of 31 independent MELAS patients and 1 out of 29 CPEO patients, but absent in the 5 MERRF and 50 controls tested. Southern blot analysis confirmed that the mutant DNA always coexists with the wild-type DNA (heteroplasmy).
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PMID:A mutation in the tRNA(Leu)(UUR) gene associated with the MELAS subgroup of mitochondrial encephalomyopathies. 171 Mar 18

Two infants who had clinical and radiographic findings consistent with Leigh syndrome were found to have deficiency of complex I (reduced nicotinamide-adenine dinucleotide--coenzyme Q reductase) activity. Significant abnormalities were found on computed tomographic scans and magnetic resonance images of the brain. Lactate and pyruvate concentrations in blood and cerebrospinal fluid were elevated, and muscle biopsy specimens showed abnormal mitochondria. These data indicate that Leigh syndrome, as well as MELAS syndrome (mitochondrial encephalopathy, myopathy, lactic acidosis, and stroke-like episodes) may result from complex I deficiency.
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PMID:Complex I (reduced nicotinamide-adenine dinucleotide-coenzyme Q reductase) deficiency in two patients with probable Leigh syndrome. 210 30

We carried out a histological examination of the extraocular muscles (EOMs) in a case of myoclonus epilepsy associated with ragged-red fibers (MERRF) and two cases of mitochondrial myopathy, encephalopathy, lactic acidosis, and stroke-like episodes (MELAS), which did not manifest external ophthalmoplegia clinically. By light microscopy, many granular and vesicular fibers were seen associated with endomysial fibrosis. Electron microscopy revealed that the fibers showed prominent accumulation of abnormal mitochondria, extensive loss of myofibrils, proliferation of free sarcoplasmic reticulum and an increased amount of lipid vacuoles. These changes were more pronounced in MELAS than in MERRF. Hirano bodies were often seen in the subsarcolemmal area of muscle fibers and also in the intramuscular myelinated nerve fibers and axon terminals. These findings suggest the presence of mitochondrial myopathy of the EOMs in cases of MELAS and MERRF.
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PMID:Involvement of extraocular muscle in mitochondrial encephalomyopathy. 211 41

The pattern of epilepsy and other convulsive disorders in 1,000 consecutive Saudi nationals is described. These disorders were common with a hospital frequency rate of 8 per 1,000. Men were more frequently affected than women and 60% of the patients were under 10 years old at the onset of their illness. The epilepsies were the commonest type (74%). Febrile convulsions (20%) presented mainly between the ages of one and five years. Isolated seizures (3%) and acute symptomatic convulsions (3%) were uncommon. In the epileptic group, generalised seizures (71%) were more frequent than partial (29%) and complex partial seizures occurred mainly in those above 21 years old. Absences (4%), infantile spasms (3%) and atonic seizures (3%) were uncommon. No specific etiology of the epilepsy was determined in the majority of the cases (63%). The identified major etiologic factors of the epilepsies were perinatal encephalopathy (21%), cerebral trauma (11%), sequelae of meningitis or encephalitis (2%), brain tumors (0.5%), and vascular lesions such as stroke and arteriovenous malformation. Perinatal encephalopathy accounted for 40% of the epilepsies in children less than 5 years old, and trauma for 20% of those above 20 years old. A family history of epilepsy in close relations was obtained in 23% of the cases, and the consanguinity rate among the parents was 53%. The high incidence of associated perinatal encephalopathy found in this study suggests that perinatal factors play a major role in the pathogenesis of epilepsy in Saudi Arabia. The high frequency of cerebral trauma was also striking. Although consanguinity of the parents appeared not to be a major factor in the genetics of convulsive disorders in this environment, it might have potentiated the tendency of familial aggregation of convulsive disorders in this community. Consanguinity may be an important factor in the production of some of these disorders but its precise role has not been determined.
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PMID:Epilepsy and other convulsive disorders in Saudi Arabia: a prospective study of 1,000 consecutive cases. 212 16

A total of 112 patients with ischemic stroke and 115 patients of different sexes and age with dyscirculatory encephalopathy were examined for the main risk factors of cardiovascular diseases. Hypokinesia and obesity were most common in chronic vascular brain pathology whereas frequently occurring and prolonged psychoemotional overstrain, aggravated heredity and alcohol abuse promoted the occurrence of acute disorders of brain circulation. The combination of 4 and more risk factors significantly raises the probability of acute cerebral ischemia.
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PMID:[Risk factors of acute and chronic cerebral ischemia]. 215 17

Cultured skin fibroblasts from patients with lacticacidemia were incubated with glucose for 1 h and the lactate and pyruvate production measured. Those patients with increased lactate to pyruvate ratios were further analyzed for the cause of the abnormal redox state. Two categories of patients are described. The first contains patients with either severe or partial cytochrome oxidase deficiency; this group can be broken down further into patients with Leigh's disease, Kearns-Sayre syndrome, and liver-specific cytochrome oxidase deficiency. In this group, the rise in lactate to pyruvate ratio roughly correlated with the severity of the defect. The second patient category had defects located in complex I of the mitochondrial respiratory chain. This is easily demonstrated in the most severely affected patients with the fatal infantile form of the disease. Patients with severe defects in either complex I or cytochrome oxidase had complexes that were only partially assembled. Patients with mitochondrial encephalopathy with lactic acidosis and stroke-like episodes demonstrated only minor changes in redox state and in the behavior of the mitochondrial respiratory chain.
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PMID:The use of skin fibroblast cultures in the detection of respiratory chain defects in patients with lacticacidemia. 217 27

The authors assessed liquor biochemical indices, mainly enzymes, on day 1-3 of hemispheric ischemic stroke in correlation with brain infarction size in 90 relevant male patients (mean age 70 +/- 6 years). The brain damage was verified by computed tomography with measuring the infarction lesion. The latter in view, the patients were assigned in three groups: with ischemic lesion less than 5.0 cm3, less than 30 cm3 and greater than 30.0 cm3 or/and multiple lesions. The results were compared with those in patients who had suffered hemispheric ischemic stroke followed by discirculatory encephalopathy.
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PMID:[Relation between biochemical indicators of the cerebrospinal fluid and the extent of cerebral infarction]. 217 85

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


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