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

'Myofibrillar myopathy' defines a myopathic condition with focal myofibrillar destruction and accumulation of degraded myofibrillar elements. Despite the fact that a number of mutations in different genes as well as cytotoxic agents lead to the disease, abnormal accumulation of desmin is a typical, common feature. Pathological changes of mitochondrial morphology and function have been observed in animal models with intermediate filament pathology. Therefore, in the present study we tested for mitochondrial pathology in skeletal muscle of five patients with the pathohistological diagnosis of myofibrillar myopathy. Screening for large-scale mtDNA deletions and the frequent MERRF (myoclonic epilepsy; ragged red fibres) and MELAS (mitochondrial encephalomyopathy; lactic acidosis; stroke) point mutations was negative in all patients. Histologically, all muscle biopsies showed nonspecific abnormalities of the oxidative/mitochondrial enzyme stainings (histochemistry for reduced nicotinamide adenine dinucleotide, succinic dehydrogenase, cytochrome c oxidase), only one of them had ragged red fibres and a significant number of cytochrome c oxidase-negative fibres. Upon biochemical investigation, four of our patients showed pathologically low respiratory chain complex I activities. Only one of our patients had a pathologically low complex IV activity, while the measurements of the others were within low normal range. The single patient with pathological values for both complex I and IV was the one with the clear histological hallmarks (ragged red and cytochrome c oxidase-negative fibres) of mitochondrial pathology. She also was the only patient with clinical signs hinting at a mitochondrial disorder. Together with data from observations in desmin- and plectin-deficient mice, our results support the view that desmin intermediate filament pathology in these cases is closely linked to mitochondrial dysfunction in skeletal muscle.
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PMID:Mitochondrial dysfunction in myofibrillar myopathy. 1258 39

Epilepsia Partialis Continua (EPC), a subtype of status epilepticus has varied etiology and the outcome depends on the cause. The aim of this study was to analyze the demographic, semiology, etiology, radiological findings, therapeutic response and outcome of EPC. This is a retrospective analysis of 76 patients (M:F: 46:30; mean age: 30.2+/-23.4 years; median age: 26 years) evaluated at our center over last 14 years. Twenty-three subjects (30.3%) had epilepsy for a mean of 25.8+/-52.3 months (range: 1-81 years; median: 14) before developing EPC and in half of them, seizures were controlled with anti-epileptic drugs (AEDs). Rest 53 (69.3%) manifested as de novo. The mean duration of EPC was 47.02+/-188.2 days (range: 1h to 48 months; median: 3 days). One patient of generalized convulsive SE (GCSE) evolved into EPC while five patients of EPC evolved into GCSE. CT scan of brain (n-76) was abnormal in 53 (69.7%) while all the 11 MRI scans which were available were abnormal. EEG (n-21) was abnormal in all but one, however it was non-specific in 7. The diagnoses were-idiopathic: 17, ischemic stroke: 15, meningo-encephalitis: 8, Rasmussen's encephalitis (RE): 7, granuloma: 6, diabetic-non-ketotic-hyperosmolar-coma (DNKHC): 6, CNS malignancies (primary/secondary): 4, birth injury: 4, cerebral venous thrombosis: 3, CNS tuberculosis: 2, and cerebritis, HIV-related, toxemia of pregnancy, and MERRF one each. Patients of >40 years (n=21) had stroke (10), idiopathic (6), DNKHC (4) and metastasis (1) as common causes. Only 12 of them received single AED, while others required 2 or more AEDs to control the seizures. The outcome (n=72) was-controlled: 43 (59.7%); uncontrolled: 26 (36.1%) (RE: 7, idiopathic: 5, birth injury: 4, encephalitis: 3, malignancy: 2, granuloma and MERRF: 1 each) and three patients succumbed (encephalitis: 2, idiopathic: 1). Causes of EPC are varied and it depends on age. Underlying cause determined the outcome and could be refractory in RE, idiopathic, and when associated with birth injury, malignancy and encephalitis. Treatment of underlying cause is essential in addition to AEDs.
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PMID:Epilepsia Partialis Continua over last 14 years: experience from a tertiary care center from south India. 1729 88

Mitochondrial encephalopathies are a group of diseases that have as their pathogenic basis an alteration of the mitochondrial DNA (mtDNA). The MELAS phenotype (mitochondrial encephalomyopathy with lactic acidosis and stroke-like episodes) has been related to mutation A3243G in approximately 80% of the cases reported. MERRF (epilepsy myoclonus with ragged red fibers) has been related to mutation A8344G and A8566G of tRNA Lys. We report the case of a 7 months-old female with early clinical signs of encephalopathy associated to the A3243G mutation. Laboratory tests showed lactic acidosis and the EEG pattern was compatible with an encephalopathic process. The infant was treated with ACTH during one month, with clinical and electroencephalographic improvements. Currently, she is receiving treatment with B-vitamins, L-Carnitine and urinary alkalizing agents. It is concluded that an analysis of mtDNA must be made in infants who present convulsions, delay in their psychomotor development, lactic acidosis and an EEG pattern compatible with an encephalopathy, to rule out a mitochondrial disease.
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PMID:[Infantile encephalopathy associated with the MELAS A3243G mutation. Case report]. 1759 46

We developed an oligonucleotide biochip for synchronous multiplex detection of 31 known mitochondrial DNA mutations associated with MELAS (Mitochondrial encephalomyopathy with lactic acidosis and stroke-like episodes) and MERRF (Myoclonic epilepsy with ragged red fibers). Allele-specific oligonucleotide probes were covalently immobilized on aldehyde modified glass slides, and then hybridized with Cy5-labled DNA fragments amplified from sample DNAs by a multiplex asymmetric PCR (MAP) method. Five patients with MELAS, 5 patients with MERRF and 20 healthy controls were investigated using the oligonucleotide biochip. The results showed that all the cases with MELAS had an A3243G mutation in the MT-TL1 gene. In the MERRF group, 4 cases were found to be an A8344G mutation and 1 case was a T8356C mutation, and both mutations were in the MT-TK gene. In the healthy controls, none of the 31 related mutations was found. The results of the DNA biochip were consistent with those by DNA sequencing. Clearly, the DNA biochip combined with MAP method would become a valuable tool in multiplex detecting of the point mutations in mtDNA leading to MELAS and/or MERRF syndrome. Moreover, this biochip format could be modified to extend to the screening scope of SNPs for any other human mitochondrial diseases.
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PMID:[Development of a DNA biochip for detection of known mtDNA mutations associated with MELAS and MERRF syndromes.]. 1893 Aug 87

The organ most frequently affected in mitochondrial disorders, particularly respiratory chain diseases (RCDs), in addition to the skeletal muscle, is the central nervous system (CNS). CNS manifestations of RCDs comprise stroke-like episodes, epilepsy, migraine, ataxia, spasticity, movement disorders, psychiatric disorders, cognitive decline, or even dementia (mitochondrial dementia). So far mitochondrial dementia has been reported in MELAS, MERRF, LHON, CPEO, KSS, MNGIE, NARP, Leigh syndrome, and Alpers-Huttenlocher disease. Mitochondrial dementia not only results from mutations in the mitochondrial genome but also from mutations in nuclear genes, such as POLG, thymidine kinase 2, or DDP1. Often mitochondrial dementia starts with specific cognitive deficits, particularly in visual construction, attention, abstraction, or flexibility but without a general intellectual deterioration. Cognitive impairment in RCDs is diagnosed upon neuropsychological testing, imaging studies, such as MRI, PET, or MR-spectroscopy, CSF-investigations, or electroencephalography. Therapy of mitochondrial dementia relies on symptomatic measures. Only single patients profit from cholinesterase inhibitors or memantine, antioxidants, vitamins, coenzyme-Q, or other substitutes. Overall, mitochondrial dementia is an important differential of dementias and should be considered in patients with multi-system disease.
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PMID:Mitochondrial disorders, cognitive impairment and dementia. 1926 75

Aim of this review is to discuss recent findings concerning the management of stroke-like episodes (SLEs) in patients with mitochondrial disorders (MIDs). Various databases were searched for appropriate literature. SLEs are a dominant feature of MIDs and occur most frequently in MELAS-syndrome, less frequently in MERRF-syndrome, Kearns-Sayre-syndrome, or Leigh-syndrome. SLEs occur at all ages and are frequently accompanied by other cerebral abnormalities. Clinically, SLEs mimic ischemic stroke but not on imaging studies and concerning the management. The morphological equivalent on MRI is the stroke-like-lesion, representing a vasogenic edema (hyperintensity on T2, diffusion-weighted imaging and apparent diffusion coefficient in the acute and subacute or chronic stage, most frequently in the parieto-occipital region, surpassing vascular territories). For diagnostic and therapeutic reasons SLEs need to be clearly delineated from ischemic stroke and cerebral bleeding. Though there is no causal therapy available, symptomatic and general measures can help to resolve the clinical manifestations. In conclusion this review shows that SLEs are a dominant feature of some syndromic or non-syndromic MIDs. The most effective strategy for the treatment of SLEs appears to be the application of L-arginine, coenzyme-Q, steroids, edaravone, creatine-monohydrate, or dichloracetate.
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PMID:Management of mitochondrial stroke-like-episodes. 1978 Aug 7

Mitochondrial diseases associated with mutations within mitochondrial genome are a subgroup of metabolic disorders since their common consequence is reduced metabolic efficiency caused by impaired oxidative phophorylation and shortage of ATP. Although the vast majority of mitochondrial proteins (approximately 1500) is encoded by nuclear genome, mtDNA encodes 11 subunits of respiratory chain complexes, 2 subunits of ATP synthase, 22 tRNAs and 2 rRNAs. Up to now, more than 250 pathogenic mutations have been described within mtDNA. The most common are point mutations in genes encoding mitochondrial tRNAs such as 3243A-->G and 8344T-->G that cause, respectively, MELAS (mitochondrial encephalopathy, lactic acidosis and stroke-like episodes) or MIDD (maternally-inherited diabetes and deafness) and MERRF (myoclonic epilepsy with ragged red fibres) syndromes. There have been also found mutations in genes encoding subunits of ATP synthase such as 8993T-->G substitution associated with NARP (neuropathy, ataxia and retinitis pigmentosa) syndrome. It is worth to note that mitochondrial dysfunction can also be caused by mutations within nuclear genes coding for mitochondrial proteins.
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PMID:[Diseases caused by mutations in mitochondrial DNA]. 2191 24

Mitochondrial DNA mutations that cause mitochondrial dysfunction are responsible for a wide spectrum of human diseases, referred to as mitochondrial diseases. Pathogenic point mutations are found frequently in genes encoding mitochondrial (mt) tRNAs, indicating that impaired functioning of mutant mt tRNAs is the primary cause of mitochondrial dysfunction. Our previous studies revealed the absence of posttranscriptional taurine modification at the anticodon wobble uridine in mutant mt tRNAs isolated from cells derived from patients with two major classes of mitochondrial diseases, MELAS (mitochondrial myopathy, encephalopathy, lactic acidosis, and stroke-like episodes) and MERRF (myoclonus epilepsy associated with ragged red fibers). Defective taurine modification of the mutant mt tRNAs results in a deficiency in protein synthesis as the cognate codons of the mutant mt tRNA cannot be decoded. These findings represent the first evidence of a molecular pathogenesis caused by an RNA modification disorder.
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PMID:Human mitochondrial diseases caused by lack of taurine modification in mitochondrial tRNAs. 2195 23

Mitochondrial disorders are clinically and genetically heterogeneous. There are a set of recurrent point mutations in the mitochondrial DNA (mtDNA) that are responsible for common mitochondrial diseases, including MELAS (mitochondrial encephalopathy, lactic acidosis, stroke-like episodes), MERRF (myoclonic epilepsy and ragged red fibers), LHON (Leber's hereditary optic neuropathy), NARP (neuropathy, ataxia, retinitis pigmentosa), and Leigh syndrome. Most of the pathogenic mtDNA point mutations are present in the heteroplasmic state, meaning that the wild-type and mutant-containing mtDNA molecules are coexisting. Clinical heterogeneity may be due to the degree of mutant load (heteroplasmy) and distribution of heteroplasmic mutations in affected tissues. Additionally, Kearns-Sayre syndrome and Pearson syndrome are caused by large mtDNA deletions. In this chapter, we describe a multiplex PCR/allele-specific oligonucleotide (ASO) hybridization method for the screening of 13 common point mutations. This method allows the detection of low percentage of mutant heteroplasmy. In addition, a nonradioactive Southern blot hybridization protocol for the analysis of mtDNA large deletions is also described.
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PMID:Analysis of common mitochondrial DNA mutations by allele-specific oligonucleotide and Southern blot hybridization. 2221 54

Mitochondrial respiratory chain disorders are relatively common inborn errors of energy metabolism, with a combined prevalence of one in 5000. These disorders typically affect tissues with high energy requirements, and cerebral involvement occurs frequently in childhood, often manifesting in seizures. Mitochondrial diseases are genetically heterogeneous; to date, mutations have been reported in all 37 mitochondrially encoded genes and more than 80 nuclear genes. The major genetic causes of mitochondrial epilepsy are mitochondrial DNA mutations (including those typically associated with the mitochondrial encephalomyopathy, lactic acidosis, and stroke-like episodes [MELAS] and myoclonic epilepsy with ragged red fibres [MERRF] syndromes); mutations in POLG (classically associated with Alpers syndrome but also presenting as the mitochondrial recessive ataxia syndrome [MIRAS], spinocerebellar ataxia with epilepsy [SCAE], and myoclonus, epilepsy, myopathy, sensory ataxia [MEMSA] syndromes in older individuals) and other disorders of mitochondrial DNA maintenance; complex I deficiency; disorders of coenzyme Q(10) biosynthesis; and disorders of mitochondrial translation such as RARS2 mutations. It is not clear why some genetic defects, but not others, are particularly associated with seizures. Epilepsy may be the presenting feature of mitochondrial disease but is often part of a multisystem clinical presentation. Mitochondrial epilepsy may be very difficult to manage, and is often a poor prognostic feature. At present there are no curative treatments for mitochondrial disease. Individuals with mitochondrial epilepsy are frequently prescribed multiple anticonvulsants, and the role of vitamins and other nutritional supplements and the ketogenic diet remain unproven.
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PMID:Mitochondrial disease and epilepsy. 2228 95


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