Archive for the ‘Muscular Dystrophy’ Category

[Merosin-deficient congenital muscular dystrophy]

Sunday, July 11th, 2010
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Painful camptocormia: the relevance of shaking your patient’s hand.

Sunday, July 11th, 2010

Camptocormia is an abnormal posture with marked flexion of thoracolumbar spine that abates in the recumbent position. Camptocormia has been described in various neurological (Parkinsonism), muscular (myopathy), psychogenic or orthopedic disorders. There are several hypotheses that can explain this impaired posture but they are usually related to the concomitant pathologies. We report the first case of a patient with confirmed myotonic dystrophy addressed to our medical center for impaired posture who underwent extensive medical exams and explorations because of a myotonic hand. Axial weakness and muscle atrophy, validated by CT-scan imaging, are discussed independent of the concomitant pathology (Parkinson, myopathy).

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Three-dimensional porous scaffold allows long-term wild-type cell delivery in dystrophic muscle.

Sunday, July 11th, 2010

Duchenne muscular dystrophy (DMD) is caused by the lack of dystrophin; affected muscles are characterized by continuous bouts of muscle degeneration, eventually leading to the exhaustion of the endogenous satellite cell pool. At present, only palliative treatments are available, although several gene and cell therapy-based approaches are being studied. In this study we proposed to overcome the limitations hampering intramuscular cell injection by using a biomaterial-based strategy. In particular, we used a three-dimensional (3D) collagen porous scaffold to deliver myogenic precursor cells (MPCs) in vivo in the mdx murine model of DMD. MPCs, derived from single fibres of wild-type donors, were expanded in vitro, seeded onto collagen scaffolds and implanted into the tibialis anterior muscles of normal and mdx mice. As a control, cells were delivered via direct intramuscular cell injection in the contralateral muscles. Scaffold-delivered MPCs displayed lower apoptosis and higher proliferation than injected cells; in terms of dystrophin restoration, collagen scaffolds yielded better results than direct injections. Importantly, time-course experiments indicated that the scaffolds acted as a cell reservoir, although cell migration was mostly contained within 400 microm from the scaffold-host tissue interface. Copyright (c) 2010 John Wiley & Sons, Ltd.

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Alternative splicing and muscular dystrophy.

Thursday, July 8th, 2010

Alternative splicing of pre-mRNAs is a major contributor to proteomic diversity and to the control of gene expression in higher eukaryotic cells. For this reasons, alternative splicing is tightly regulated in different tissues and developmental stages and its disruption can lead to a wide range of human disorders. The aim of this review is to focus on the relevance of alternative splicing for muscle function and muscle disease. We begin by giving a brief overview of alternative splicing, muscle-specific gene expression and muscular dystrophy. Next, to illustrate these concepts we focus on two muscular dystrophy, myotonic muscular dystrophy and facioscapulohumeral muscular dystrophy, both associated to disruption of splicing regulation in muscle.

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Retinal arterial but not venous tortuosity correlates with facioscapulohumeral muscular dystrophy severity.

Thursday, July 8th, 2010

BACKGROUND: Facioscapulohumeral muscular dystrophy (FSHD) is an autosomal-dominant disease beginning with facial and shoulder girdle weakness with variable progression. Exudative retinal detachment, retinal vessel irregularities on fluorescein angiography, and retinal vessel tortuosity have been found in association with FSHD. METHODS: In this retrospective study, muscle affectedness severity was rated as mild, moderate, or severe by a neurologist masked to the retinal images. Three ophthalmologists masked to disease severity graded the degree of arterial and venous tortuosity on a scale of 1 to 4. An automated method estimated an index of tortuosity for arteries and veins from color fundus photographs. Spearman rank correlation coefficients were used to describe the relationship between retinal vessel tortuosity and disease severity. RESULTS: Seven patients with an average age of 13 years (range, 7-36 years) were selected. Correlation between the subjective tortuosity for arteries, and the severity of FSHD was 0.78 (p = 0.039). The correlation coefficient for venous tortuosity was -0.06 and was not significant (p = 0.882). The correlation coefficient between the average algorithmic computer-generated tortuosity indices for arteries and FSHD severity was high (0.85, p = 0.016), but for veins it was low and not significant (0.19, p = 0.662). CONCLUSIONS: The authors of previous reports have shown retinal vascular abnormalities did not correlate to FSHD disease severity. Our results suggest a correlation between the tortuosity of arteries and the severity of disease in FSHD patients. These results suggest the tortuosity of arteries can serve as a biomarker of severity of disease in these FSHD patients, either as determined by human experts or by an automated method. Copyright © 2010 American Association for Pediatric Ophthalmology and Strabismus. Published by Mosby, Inc. All rights reserved.

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Molecular aspects of cyclophilins mediating therapeutic actions of their ligands.

Thursday, July 8th, 2010

Cyclosporine A (CsA) is an immunosuppressive cyclic peptide that binds with a high affinity to 18 kDa human cyclophilin-A (hCyPA). CsA and its several natural derivatives have some pharmacological potential in treatment of diverse immune disorders. More than 20 paralogues of CyPA are expressed in the human body while expression levels and functions of numerous ORFs encoding cyclophilin-like sequences remain unknown. Certain derivatives of CsA devoid of immunosuppressive activity may have some potential in treatments of Alzheimer diseases, Hepatitis C and HIV infections, amyotrophic lateral sclerosis, congenital muscular dystrophy, asthma and various parasitic infections. Here, we discuss structural and functional aspects of the human cyclophilins and their interaction with various intra-cellular targets that can be under the control of CsA or its complexes with diverse cyclophilins that are selectively expressed in different cellular compartments. Some molecular aspects of the cyclophilins expressed in parasites invading humans and causing diseases were also analyzed.

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Electrocardiographic Abnormalities and Arrhythmias are Strongly Associated with the Development of Cardiomyopathy in Muscular Dystrophy.

Thursday, July 8th, 2010

OBJECTIVE:: Assess the utility of electrocardiography in patients with muscular dystrophy. BACKGROUND:: Dilated cardiomyopathy is a well-recognized sequela of muscular dystrophy (MD). Early identification of cardiac involvement with timely therapy can favorably impact outcome. We hypothesize that electrocardiography can be a useful adjunct in the identification of DCM in MD. METHODS:: A retrospective review of patients with MD was performed. ECGs and Holters were analyzed to assess for association between abnormalities and the development of DCM. RESULTS:: One-hundred-fifty patients were identified. Forty-three percent of patients (64/150) developed DCM. ECG abnormalities were found in 65% of patients and correlated well with the presence of DCM with 60/64 (94%) with DCM having an abnormal ECG vs. 38/86 (44%) without DCM (p<0.001). Only 4/52 (8%) of patients with normal ECGs had DCM. The presence of ECG abnormalities was highly sensitive (95.8%) but not specific (40.1%) to the presence of DCM. ECG abnormalities often preceded the development of DCM by a significant period of time (3.7+/-2.6 years). Arrhythmias were common with 17/150 (11%) of the cohort being affected. Those with DCM were significantly more likely to have an arrhythmia with 16/64 (25%) of that group being affected (p < 0.01). The presence of VT was a poor prognostic indicator with 6/11 patients dying within 0.68+/-0.41 years. CONCLUSIONS:: ECG abnormalities are strongly associated with DCM in patients with MD and frequently precede cardiac dysfunction by several years. Arrhythmias are common and periodic ECG and Holter evaluations are warranted as they may predict early cardiac involvement. Copyright © 2010. Published by Elsevier Inc.

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The Electrocardiogram: A Useful Screening Test for Cardiac Involvement in Some But Not All of the Muscular Dystrophies.

Thursday, July 8th, 2010
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Gait patterns comparison of children with Duchenne muscular dystrophy to those of control subjects considering the effect of gait velocity.

Thursday, July 8th, 2010

3D analysis of the gait of children with Duchenne muscular dystrophy (DMD) was the topic of only a few studies and none of these considered the effect of gait velocity on the gait parameters of children with DMD. Gait parameters of 11 children with DMD were compared to those of 14 control children while considering the effect of gait velocity using 3D biomechanical analysis. Kinematic and kinetic gait parameters were measured using an Optotrak motion analysis system and AMTI force plates embedded in the floor. The data profiles of children with DMD walking at natural gait velocity were compared to those of the control children who walked at both natural and slow gait velocities. When both groups walked at similar velocity, children with DMD had higher cadence and shorter step length. They demonstrated a lower hip extension moment as well as a minimal or absent knee extension moment. At the ankle, a dorsiflexion moment was absent at heel strike due to the anterior location of the center of pressure. The magnitude of the medio-lateral ground reaction force was higher in children with DMD. Despite this increase, the hip abductor moment was lower. Hip power generation was also observed at the mid-stance in DMD children. These results suggest that most of the modifications observed are strategies used by children with DMD to cope with possible muscle weakness in order to provide support, propulsion and balance of the body during gait. Copyright © 2010. Published by Elsevier B.V.

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Age-Related Differences in Lower-Limb Muscle Cross-Sectional Area and Torque Production in Boys With Duchenne Muscular Dystrophy.

Thursday, July 8th, 2010

Mathur S, Lott DJ, Senesac C, Germain SA, Vohra RS, Sweeney HL, Walter GA, Vandenborne K. Age-related differences in lower-limb muscle cross-sectional area and torque production in boys with Duchenne muscular dystrophy. OBJECTIVE: To examine the relationship between lower-extremity muscle cross-sectional area, muscle strength, specific torque, and age in ambulatory boys with Duchenne muscular dystrophy (DMD) compared with controls. DESIGN: Observational cross-sectional study. SETTING: University research setting. PARTICIPANTS: Volunteer sample of boys with DMD (n=22) and healthy control boys (n=10), ages 5 through 14 years. INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: Maximal muscle cross-sectional area (CSA(max)) assessed by magnetic resonance imaging of quadriceps, plantarflexors (PFs) and dorsiflexors (DFs), peak isometric torque from dynamometry, and timed functional tests. RESULTS: The average CSA(max) of the triceps surae muscle group was approximately 60% higher in boys with DMD compared with controls (39.1+/-13.6 cm(2) vs 24.5+/-9.3 cm(2); P=.002), while the tibialis anterior muscle showed age-appropriate increases in CSA(max). The increase in quadriceps CSA(max) was also distinctly different in boys with DMD compared with controls. Specific torque (ie, peak torque/CSA(max)) was impaired in all 3 muscles groups, with the knee extensor (KE) and PF muscles showing 4-fold, and the DF muscles 2-fold, higher values in controls compared with boys with DMD. Large age-related gains in specific torque were observed in all 3 muscle groups of control subjects, which were absent in ambulatory boys with DMD. Correlations were observed between performance on functional tasks and quadriceps and PF torque production (r=-.45 to -.57, P<.05), but not with DF strength. CONCLUSIONS: Age-related changes in muscle cross-sectional area and specific torque production in lower-extremity muscles showed distinctly different patterns in the KE, PF, and DF muscles of boys with DMD compared with controls. Copyright © 2010 American Congress of Rehabilitation Medicine. Published by Elsevier Inc. All rights reserved.

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