| 1. |
- Hammarén, Elisabet, et al.
(författare)
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Modified exercise test in screening for mitochondrial myopathies--adjustment of workload in relation to muscle strength.
- 2003
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Ingår i: European neurology. - : S. Karger AG. - 0014-3022 .- 1421-9913. ; 51:1, s. 38-41
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Tidskriftsartikel (refereegranskat)abstract
- The aim of this study was to evaluate the usefulness of a modification of the bicycle ergometer test, the subanaerobic threshold exercise test (SATET), as a screening test for patients with mitochondrial myopathies. Since the original SATET is frequently found to be strenuous for weak patients, a new variable (relative muscle strength) was added to the workload formula. Plasma lactate levels were recorded at rest, then after 5 and 15 min of cycling on an ergometer, with constant workload. Nine patients with mitochondrial myopathy, 10 patients with other neuromuscular diseases and 9 healthy but sedentary volunteers undertook the test. An upper reference limit after exercise for plasma lactate was settled at 2.9 mmol/l. The modified SATET showed a sensitivity of 78% and a specificity compared to the healthy subjects of 100%. Compared to patients with other neuromuscular diseases, the specificity was lower (60%). All subjects completed the test without severe fatigue or pain.
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| 2. |
- Moslemi, Ali-Reza, et al.
(författare)
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A novel mutation in the mitochondrial tRNA(Phe) gene associated with mitochondrial myopathy
- 2004
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Ingår i: Neuromuscul Disord. ; 14:1, s. 46-50
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Tidskriftsartikel (refereegranskat)abstract
- We report a novel heteroplasmic T-->C mutation at nt position 582 within the mitochondrial tRNA(Phe) gene of a 70-year-old woman with mitochondrial myopathy. No other family members were affected, suggesting that our patient was a sporadic case. The muscle showed frequent ragged red fibers and 43% cytochrome c oxidase deficient fibers. The mutation alters a conserved base pairing in the aminoacyl acceptor stem. The mutation load was 70% in muscle homogenate and varied from 0 to 95% in individual muscle fiber segments. Cytochrome c oxidase-negative fibers showed significantly higher levels of mutated mtDNA (>75%) than Cytochrome c oxidase-positive fibers (<55%). This mutation adds to the previously described four pathogenic mutations in the tRNA(Phe) gene.
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| 3. |
- Oldfors, Anders, 1951, et al.
(författare)
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Myopathies associated with myosin heavy chain mutations
- 2004
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Ingår i: Acta myologica : myopathies and cardiomyopathies : official journal of the Mediterranean Society of Myology / edited by the Gaetano Conte Academy for the study of striated muscle diseases. - : The Mediterranean Society of Myology. - 1128-2460. ; 23:2, s. 90-6
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Tidskriftsartikel (refereegranskat)abstract
- Myosin, a molecular motor, converts chemical energy into mechanical force. The motor domain of myosin heavy chain (MyHC) includes an ATP binding region with ATPase activity and an actin-binding region. Motor function is achieved by conformational changes, at hydrolysis, of ATP causing a shift in the angle between the actin binding head and the rod region of the molecule. The elongated alpha-helical coiled-coil rod region of MyHC molecules constitutes the major part of the thick filaments of the sarcomere. Three major MyHC isoforms are expressed in human skeletal muscle (type I, MYH7, expressed in type 1 fibres; IIa, MYH2, expressed in 2A fibres; IIx, MYH1, expressed in 2B fibres). While mutations in slow/beta cardiac MyHC (MYH7) are a common cause of familial hypertrophic cardiomyopathy, no skeletal myopathies have, until recently, been associated with mutations in MyHC. A heterozygous mutation, Glu706Lys, in the core of the head of MyHC IIa is associated with a familial congenital myopathy, which, in most instances, has shown mild phenotypic expression in children but progressive course in some adults. There is a relationship between the level of expression of mutated MyHC IIa and muscle pathology. Some adults with a progressive course show muscle fibres with rimmed vacuoles and filaments of the type seen in inclusion body myositis/myopathy (IBM). Endurance training in a group of affected patients caused a shift in the expression of myosin from fast (IIx) to slow (I) isoforms but no reduction in the expression of MyHC IIa. A heterozygous mutation, Arg1845Trp, in the distal rod region of slow myosin (type I, MYH7) is associated with familial congenital myopathy, with large deposits of MyHC I in the subsarcolemmal region of type 1 muscle fibres, "Myosin storage myopathy". These patients showed slowly progressive muscle weakness but no overt cardiomyopathy. These two muscle diseases, which are caused by mutations in MyHC, form the basis of a novel entity: "Myosin myopathies".
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| 4. |
- Tajsharghi, Homa, 1968, et al.
(författare)
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Myosin storage myopathy associated with a heterozygous missense mutation in MYH7.
- 2003
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Ingår i: Annals of neurology. - : Wiley. - 0364-5134 .- 1531-8249. ; 54:4, s. 494-500
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Tidskriftsartikel (refereegranskat)abstract
- Myosin constitutes the major part of the thick filaments in the contractile apparatus of striated muscle. MYH7 encodes the slow/beta-cardiac myosin heavy chain (MyHC), which is the main MyHC isoform in slow, oxidative, type 1 muscle fibers of skeletal muscle. It is also the major MyHC isoform of cardiac ventricles. Numerous missense mutations in the globular head of slow/beta-cardiac MyHC are associated with familial hypertrophic cardiomyopathy. We identified a missense mutation, Arg1845Trp, in the rod region of slow/beta-cardiac MyHC in patients with a skeletal myopathy from two different families. The myopathy was characterized by muscle weakness and wasting with onset in childhood and slow progression, but no overt cardiomyopathy. Slow, oxidative, type 1 muscle fibers showed large inclusions consisting of slow/beta-cardiac MyHC. The features were similar to a previously described entity: hyaline body myopathy. Our findings indicate that the mutated residue of slow/beta-cardiac MyHC is essential for the assembly of thick filaments in skeletal muscle. We propose the term myosin storage myopathy for this disease.
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| 5. |
- Wentz, Kerstin, 1958, et al.
(författare)
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Psychological functioning in women with fibromyalgia: a grounded theory study.
- 2004
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Ingår i: Health care for women international. - : Informa UK Limited. - 0739-9332 .- 1096-4665. ; 25:8, s. 702-29
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Tidskriftsartikel (refereegranskat)abstract
- The aim of this study was to elucidate psychological functioning and psychological processes in women with fibromyalgia. Twenty-one females with fibromyalgia (aged 26-72 years) were interviewed in-depth. The interviews were analysed in line with grounded theory. A core concept, "unprotected self," mirroring childhood conditions and adult psychological functioning, was identified. Intense activity or hypomanic helpfulness often was used as self-regulation in adult life. Later an increased exposure to mental load is accompanied by reduction of cognitive functioning and generalised pain. The phase of persistence of fibromyalgia is marked by reduction of cognitive functions, unprotected psychological functioning, and increased mental load as from crisis and somatic symptoms.
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