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

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

The search for effective therapy of acute stroke, centres on the two strategies of restoring blood flow before ischaemia causes irreversible infarction, and moderation of the biochemical changes in ischaemic tissue that cause neuronal death. This review concentrates on the role of lactacidosis, calcium ions, free radicals, and excitatory neurotransmitters in the pathogenesis of neuronal death, and on the therapeutic possibilities in acute stroke emerging from studies in animal models.
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PMID:Protection against ischaemia: the basis of acute stroke therapy. 162 35

1. Endothelin, a novel vasoconstrictor 21-residue peptide isolated from the supernatant of cultured porcine endothelial cells, has been shown to be increased in plasma in a variety of cardiovascular disease states, including acute myocardial infarction, acute renal failure and essential hypertension. We determined the time course of plasma and pulmonary lymph endothelin-like immunoreactivity in relation to the progressive deterioration of cardiopulmonary function in an ovine septic shock model leading to multi-organ failure syndrome and death within 42 h of a continuous intravenous infusion of Escherichia coli endotoxin (40 ng min-1kg-1). 2. Plasma and pulmonary lymph endothelin-like immunoreactivity were measured by r.i.a. using a specific antiserum raised in rabbits against porcine endothelin-1. Endothelin-like immunoreactivity was further determined in lung tissue and the thoracic duct lymph of endotoxin-treated sheep by reversed-phase h.p.l.c. In control instrumented conscious sheep not infused with endotoxin, there were no significant changes in any of the measured cardiopulmonary and biochemical variables, with plasma and pulmonary lymph endothelin-like immunoreactivity remaining below the detection limit (less than 1 pg/tube) throughout the 72 h study period. 3. Conscious sheep receiving endotoxin showed a major hypotensive septic syndrome, including persistently decreased systemic blood pressure, systemic vascular resistance, stroke volume, left ventricular stroke work, associated with sustained pulmonary vasoconstriction and protein-rich pulmonary oedema (greater than five-fold increase in pulmonary lymph flow and protein clearance), and marked lactic acidosis, leading to the death of animals within 14-42 h despite institution of mechanical ventilation and adequate intravascular volume replacement.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Time course of plasma and pulmonary lymph endothelin-like immunoreactivity during sustained endotoxaemia in chronically instrumented sheep. 165 37

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

Point mutations of mitochondrial DNA have been described in the muscle of patients with syndromes of myoclonic epilepsy and ragged red fibres (MERRF) and of mitochondrial encephalopathy with lactic acidosis and stroke-like episodes (MELAS). We have found the MERRF mutation in members of 6 British kindreds; 2 of these had unusual phenotypes but all index patients had myoclonus. The MELAS mutation was detected in 17 patients from 16 families, who had a wide range of clinical features that particularly affected the central nervous system; stroke-like episodes were observed in 10.3 patients with mitochondrial DNA mutations did not have ragged red fibres on muscle biopsy, generally considered to be the morphological hallmark of mitochondrial diseases. In all 6 patients with the MERRF mutation, and 10 of 11 with the MELAS mutation, the genetic defect was easily detected in blood cells as well as muscle (blood samples were not available in 6 patients with MELAS mutations in muscle). Molecular genetic analysis of blood samples represents an inexpensive and reliable screening test for mitochondrial encephalopathies, and use of such techniques could influence diagnosis and genetic counselling in patients with seizure disorders and young-onset stroke.
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PMID:Mitochondrial encephalopathies: molecular genetic diagnosis from blood samples. 167 25

The mitochondrial DNA (mtDNA) of Japanese patients suffering from the syndrome of mitochondrial myopathy, encephalopathy, lactic acidosis and stroke-like episodes (MELAS) exhibits a specific heteroplasmic A----G transition in the tRNA(Leu) at position 3243. In this study, we investigated mtDNA from skeletal muscle, cardiac muscle, brain, liver, diaphragm, fibroblasts and blood cells of four Caucasians with MELAS, one younger healthy sister of two MELAS patients, and eleven controls. We found that 1) the mutation was present in all investigated tissues of Caucasians with MELAS but not in controls, 2) within a single patient, the tissue-specific variation of the copy number of mutated mtDNA covered the same range as in the skeletal muscle of different patients, 3) the mutation was also present in the blood cells of the healthy sister of two MELAS siblings.
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PMID:A specific point mutation in the mitochondrial genome of Caucasians with MELAS. 168 68

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

A heteroplasmic point mutation (transition A to G at position 3243 in the mitochondrial tRNA(Leu(UUR)) gene is indicative for myo-encephalopathy with lactic acidosis and stroke-like episodes (MELAS). Decreased respiratory chain complex activities measured in different tissues from four patients with MELAS syndrome do not correlate with the proportion of mutated mitochondrial genome.
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PMID:Respiratory chain activity in tissues from patients (MELAS) with a point mutation of the mitochondrial genome [tRNA(Leu(UUR))]. 171 58

We studied a family with a myopathic form of complex I deficiency with regard to the clinical symptoms, usefulness of the exercise tolerance test with an ergometer for screening of mitochondrial abnormalities, pathological findings in biopsied muscles and genetics. In this family, none of the members had disorders of the central nervous system, such as convulsions, mental deterioration or stroke-like episodes. In the two affected generations, three mothers and three children had mitochondrial abnormalities. Two children were diagnosed as having complex I deficiency. One of them, an 8-year-old girl with normal psychomotor development during infancy, began to experience easy fatigability at about 3 years of age. At the age of 5 years, she experienced respiratory distress and became unconscious. Thereafter, she had similar episodic respiratory problems with lactic acidosis. Ragged-red fibers and respiratory chain enzyme defects were detected in the biopsied muscle. Another child, a 15-year-old boy with easy fatigability but no muscle weakness, had normal respiratory chain enzyme activities and a normal oxysogram: oxygen consumption showed a normal responses when malate and pyruvate were added as substrates for the isolated mitochondria. His muscle pathology revealed rare ragged-red fibers and abnormal subsarcolemmal mitochondrial aggregation. An investigation with an ergometer showed elevated serum lactate and pyruvate levels. Only one mother had muscle weakness and hyper-lactic acidemia. The other two mothers had no muscle symptoms, but abnormal results were obtained with the ergometer.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:[Ergometric and pathologic study of a family with complex I deficiency]. 173 24

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


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