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Progressive Muscle Weakness (progressive + muscle_weakness)
Selected AbstractsImpaired myofibrillar function in the soleus muscle of mice with collagen-induced arthritisARTHRITIS & RHEUMATISM, Issue 11 2009Takashi Yamada Objective Progressive muscle weakness is a common feature in patients with rheumatoid arthritis (RA). However, little is known about whether the intrinsic contractile properties of muscle fibers are affected in RA. This study was undertaken to investigate muscle contractility and the myoplasmic free Ca2+ concentration ([Ca2+]i) in the soleus, a major postural muscle, in mice with collagen-induced arthritis (CIA). Methods Muscle contractility and [Ca2+]i were assessed in whole muscle and intact single-fiber preparations, respectively. The underlying mechanisms of contractile dysfunction were assessed by investigating redox modifications using Western blotting and antibodies against nitric oxide synthase (NOS), superoxide dismutase (SOD), 3-nitrotyrosine (3-NT), carbonyl, malondialdehyde (MDA), and S-nitrosocysteine (SNO-Cys). Results The tetanic force per cross-sectional area was markedly decreased in the soleus muscle of mice with CIA, and the change was not due to a decrease in the amplitude of [Ca2+]i transients. The reduction in force production was accompanied by slowing of the twitch contraction and relaxation and a decrease in the maximum shortening velocity. Immunoblot analyses showed a marked increase in neuronal NOS expression but not in inducible or endothelial NOS expression, which, together with the observed decrease in SOD2 expression, favors peroxynitrite formation. These changes were accompanied by increased 3-NT, carbonyl, and MDA adducts content in myofibrillar proteins from the muscles of mice with CIA. Moreover, there was a significant increase in SNO-Cys content in myosin heavy-chain and troponin I myofibrillar proteins from the soleus muscle of mice with CIA. Conclusion These findings show impaired contractile function in the soleus muscle of mice with CIA and suggest that this abnormality is due to peroxynitrite-induced modifications in myofibrillar proteins. [source] Signs and symptoms at diagnosis of amyotrophic lateral sclerosis: a population-based study in southern ItalyEUROPEAN JOURNAL OF NEUROLOGY, Issue 7 2006S. Zoccolella Amyotrophic lateral sclerosis (ALS) diagnostic criteria are used to select patients for clinical trials based on different levels of diagnostic certainty, according to the spread of upper (UMN) and lower motoneuron (LMN) signs in different anatomic regions. However, the clinical presentation of ALS patients is extremely variable and this can delay the time to diagnosis and decrease the likelihood for trial entry. The aims of the study were to describe the signs and symptoms of diagnosis in a population-based incident cohort of ALS cases, using the El Escorial (EEC) and the Revised Airlie Diagnostic Criteria (AHC). The source of the study was a prospective population-based registry established in Puglia, southern Italy, in 1997. The diagnosis and the classification of the cases were based on EEC and AHC. All incident ALS cases during the period 1998,1999 were enrolled and followed up. During the surveillance period, we identified 130 ALS incident cases, and bulbar-ALS represented 20% of our cohort. The highest risk for bulbar onset was among subjects aged >75 years [RR: 20.1, 95% confidence interval (CI) 3.4,118.0] compared with subjects aged <55 years and among females compared with males (Relative risk (RR): 2.75, 95% CI: 1,7.3). The vast majority of patients (72%) referred progressive muscle weakness in the limbs as the presenting symptom. Eighty percent of cases presented contemporary bulbar or spinal involvement; UMN signs in the bulbar region were present in 24% of cases and any motoneuronal sign in thoracic region in only 15% of the cases. In this population-based series, progressive muscle weakness was the most common presenting sign; bulbar onset was associated with advanced age and female sex. UMN signs in the bulbar region and any motoneuronal sign in the thoracic region were observed in 20% of our case series. This may represent the main limitation to show the spread of signs during diagnostic assessment for inclusion in epidemiological studies and clinical trials. [source] DMD exon 1 truncating point mutations: Amelioration of phenotype by alternative translation initiation in exon 6,HUMAN MUTATION, Issue 4 2009Olga L. Gurvich Abstract Mutations in the DMD gene result in two common phenotypes associated with progressive muscle weakness: the more severe Duchenne muscular dystrophy (DMD) and the milder Becker muscular dystrophy (BMD). We have previously identified a nonsense mutation (c.9G>A; p.Trp3X) within the first exon of the DMD gene, encoding the unique N-terminus of the 427-kDa muscle isoform of the dystrophin protein. Although this mutation would be expected to result in severe disease, the clinical phenotype is very mild BMD, with ambulation preserved into the seventh decade. We identify the molecular mechanism responsible for the amelioration of disease severity to be initiation of translation at two proximate AUG codons within exon 6. Analysis of large mutational data sets suggests that this may be a general mechanism of phenotypic rescue for point mutations within at least the first two exons of the DMD gene. Our results directly demonstrate, for the first time, the use of alternate translational initiation codons within the DMD gene, and suggest that dystrophin protein lacking amino acids encoded by the first five exons retains significant function. Hum Mutat 0:1,8, 2009. © 2009 Wiley-Liss, Inc. [source] A review of nutrition in Duchenne muscular dystrophyJOURNAL OF HUMAN NUTRITION & DIETETICS, Issue 5 2009Z. E. Davidson Abstract Duchenne muscular dystrophy (DMD) is a recessive X linked genetic disorder characterised by progressive muscle weakness and reduced muscle tone. Affecting only boys, it limits life expectancy to approximately 20 years. A literature review was conducted using MEDLINE and the Cochrane Library, employing the term ,Duchenne muscular dystrophy'. A total of 1491 articles in English were recovered. These papers were searched thematically under the headings: body composition (n = 10), energy expenditure (n = 10), nutrition (n = 6), corticosteroid therapy (n = 55) and gene therapy (n = 199). Key dietetic practice points were identified relevant to nutritional management. Papers supporting these key themes were assigned a level of evidence and grade of recommendation. There is limited high-quality evidence to guide the nutritional management of boys with DMD. Currently, the majority of evidence is based on expert opinion and clinical expertise. Delayed growth, short stature, muscle wasting and increased fat mass are characteristics of DMD and impact on nutritional status and energy requirements. The early introduction of steroids has altered the natural history of the disease, but can exacerbate weight gain in a population already susceptible to obesity. Prior to commencing steroids, anticipatory guidance for weight management should be provided. Malnutrition is a feature of end stage disease requiring a multidisciplinary approach, such as texture modification and supplemental feeding. Micronutrient requirements are yet to be determined but, as a result of corticosteroid treatment, vitamin D and calcium should be supplemented. Some evidence exists supporting supplementation with creatine monohydrate to improve muscle strength. More research is needed to provide a higher quality of evidence for dietitians working within this area. [source] | ||||||||||