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1
Rabinowitz, Adam Howard. "Antisense therapies for Duchenne muscular dystrophy". Thesis, Imperial College London, 2007. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.444590.
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2
Smith, T. J. "Molecular analysis of Duchenne muscular dystrophy". Thesis, University of Oxford, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.233559.
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3
Hodgson, Shirley V. "Genetic studies in Duchenne muscular dystrophy". Thesis, University of Oxford, 1987. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.235878.
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4
Wakefield, Philip M. "Gene therapy for duchenne muscular dystrophy". Thesis, University of Oxford, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.365743.
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5
Koppaka, Sisir. "Imaging biomarkers for Duchenne muscular dystrophy". Thesis, Massachusetts Institute of Technology, 2015. http://hdl.handle.net/1721.1/106959.
Testo completoAbstract (sommario):
Thesis: S.M., Massachusetts Institute of Technology, School of Engineering, Center for Computational Engineering, Computation for Design and Optimization Program, 2015.Cataloged from PDF version of thesis.
Includes bibliographical references (pages 75-78).
Duchenne muscular dystrophy (DMD) is the most common muscular dystrophy of childhood and affects 1 in 3600 male births. The disease is caused by mutations in the dystrophin gene leading to progressive muscle weakness which ultimately results in death due to respiratory and cardiac failure. Accurate, practical, and painless tests to diagnose DMD and measure disease progression are needed in order to test the effectiveness of new therapies. Current clinical outcome measures such as the sixminute walk test and North Star Ambulatory Assessment (NSAA) can be subjective and limited by the patient's degree of effort and cannot be accurately performed in the very young or severely affected older patients. We propose the use of image-based biomarkers with suitable machine learning algorithms instead. We find that force-controlled (precise acquisition at a certain force) and force-correlated (acquisition over a force sweep) ultrasound helps to reduce variability in the imaging process. We show that there is a high degree of inter-operator and intra-operator reliability with this integrated hardware-software setup. We also discuss how other imaging biomarkers, segmentation algorithms to target specific subregions, and better machine learning techniques may provide a boost to the performance reported. Optimizing the ultrasound image acquisition process by maximizing the peak discriminatory power of the images vis-à-vis force applied at the contact force is also discussed. The techniques presented here have the potential for providing a reliable and non-invasive method to discriminate, and eventually track the progression of DMD in patients.
by Sisir Koppaka.
S.M.
6
Tay, Shaun Li Jian. "Duchenne Muscular Dystrophy—Insight and Treatment". Thesis, The University of Arizona, 2015. http://hdl.handle.net/10150/595055.
Testo completoAbstract (sommario):
Duchenne Muscular Dystrophy (DMD) is a genetic disorder characterized by progressive degeneration of muscle fibers and dystrophic changes on muscle biopsy¹. DMD accounts for approximately 50% of all dystrophinopathies, with around 21,000 male babies born with the disease each year², ³, ⁴, ⁵. It is also the most lethal X-linked recessive disorder as phenotypic traits are not immediately present at birth¹¹, ³. Patients usually do not live past their 20's without medical intervention to treat associated respiratory and cardiac dysfunctions¹¹, ³. For these reasons DMD remains one of the greatest threats, amongst a range of pediatric pathologies, to the normalcy of child development and parental care. Although treatment options have shown to mitigate the progression of DMD, most are controversial and costly - the estimated annual treatment cost of DMD per patient is $50,953⁵⁸. In light of this, disease awareness and public health education are critical components for acquiring funds needed for research towards a cure¹². My hope is that through this integrated overview of DMD, the medical layman will better understand the depths of this lethal disease, and how it can be detrimental to both the affected child and his caretaker.
7
vianello, sara. "Molecular modifiers in Duchenne muscular dystrophy". Doctoral thesis, Università degli studi di Padova, 2018. http://hdl.handle.net/11577/3426720.
Testo completoAbstract (sommario):
Duchenne muscular dystrophy (DMD) is an X-linked progressive neuromuscular disease affecting 1:3500 –1/5000 boys at birth. It is caused by the absence of dystrophin, a subsarcolemmal protein that confers membrane stability linking cytoskeletal actin to the extracellular matrix. Dystrophin is part of a multi-protein complex called dystrophin associated protein complex (DAPC), which contains, among the other components, β-dystroglycan and nitric oxide synthase (NOS). The consequences of the absence of dystrophin are: deregulation of calcium homeostasis, tissue necrosis, and progressive accumulation of fat and fibrosis and loss of contractile muscle fibers. The ensuing muscle weakness leads to progressive and severe disability, with loss of independent ambulation around the early teens, and cardiac and respiratory failure leading to patient’s death, usually around the age of 20-30 years.Despite all patients having a complete lack of dystrophin in muscle fibers, a relevant inter-patient variability in disease severity is observed (e.g. loss of ambulation may range from 8 to beyond 15 years of age). Emerging evidence points to genetic modifiers, i.e. polymorphisms in genes different form the disease gene, as one of the causes of this variability, but little is yet known about the underlying molecular mechanisms.My PhD work can be divided into 4 aims: Aim 1: To characterize the molecular mechanism underlying the modifier effect of the rs28357094 T>G SNP in the SPP1gene, encoding osteopontin (OPN) the first identified genetic modifier of DMD. I treated dystrophic and healthy cell line with two different concentrations of deflazacort (DFZ), one of the glucocorticoids mainly used to treat DMD patients, in order to analyze osteopontin expression in relation to genetic background at rs24357094. The results obtained revealed: (I) a developmental regulated expression pattern of OPN; (II) no difference of osteopontin expression are observed related to rs28357094 genotype; (III) an increase in OPN expression only in TG DFZ-treated myotubes, suggesting a possible interaction between glucocorticoid responsive elements (GRs) in the promoter of the SPP1gene and the glucocorticoid.Aim 2: To investigate the possible roles of SPP1splicing isoforms in DMDmuscle biopsies and cells. Three SPP1isoforms, named a, b and c, were analyzed. SPP1mRNA studies revealed that all three isoforms are overexpressed in DMD muscle compared to controls, but not in myogenic cell cultures. Moreover, SPP1isoforms expression was directly correlated withage in DMD patients’ muscle biopsies. Finally, muscle biopsies carrying the rs24357094 TT genotype showed an increased expression of all three SPP1isoforms compared to TG genotype.
Aim 3: To validate the known DMD geneticmodifiers in novel cohorts of DMD patients utilizing different outcome measures. First, we asked if SPP1genotype and LTBP4haplotype (the second identified modifier of DMD) can modulate the cardiac involvement in DMD. LTBP4haplotye and the SPP1rs28357094 were genotyped in 168 DMD patients. LTBP4haplotype is composed of 4 polymorphisms in perfect linkage disequilibrium (LD). The genotype at rs10880 resulted, as expected, to be associated to a delay at age of loss of ambulation (LoA) and, as novel finding, also to a delay in cardiomyopathy onset. The SPP1minor G allele at rs28357094 resulted also associated to a later cardiomyopathy onset.Finally, I participate to the identification of the third genetic modifier in DMD: CD40. CD40was identified through a GWAS approach in a large cohort of DMD patients.The CD40rs1883832 C>T polymorphism is located within the Kozak sequence of the gene and it causes a decrease of transcriptional activity of the promoter resulting in an increase of the CD40 secreted isoform. In order to validate CD40 as a genetic modifier in DMD in an independent cohort from the discovery cohort, rs1883832 was genotyped in 96 DMD patients.DMD patients carrying the minor T allele lost ambulation earlier compared to patients carrying the C allele. Moreover, in order to study the functional role of CD40 in DMD, RT-PCR and immunoblot were performed in a subset of patients’ muscle biopsies stratified according to rs1883832 genotype. Our results reveal that the minor T allele is associated to an increase of the transcript and a decrease of the protein compared to C genotype.Taken together these data contribute to clarify some aspects of the molecular mechanisms underlying the downstream consequences of genetic modifiers in DMD. Further studies are needed to fully translate the knowledge acquired in thefield of genetic modifiers in DMD to the clinic, e.g. to implement patient genotyping for genetic counseling, prognosis, planning of treatments, and stratification in clinical trials
8
Coovert, Daniel David. "Analysis of dystrophin in duchenne muscular dystrophy and SMN in spinal muscular atrophy /". The Ohio State University, 1998. http://rave.ohiolink.edu/etdc/view?acc_num=osu1487951595500021.
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9
Smith, Philip E. M. "Breathing during sleep in Duchenne muscular dystrophy". Thesis, University of Liverpool, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.235539.
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10
Babaria, Arati. "Molecular Mechanisms that Underlie Duchenne Muscular Dystrophy". Thesis, The University of Arizona, 2016. http://hdl.handle.net/10150/612573.
Testo completoAbstract (sommario):
Duchenne muscular dystrophy is an inherited, X-linked recessive skeletal muscle disorder that is characterized by mutations in the dystrophin gene [1]. Therefore, the disease affects primarily males and women are typically carriers. 1 in 3500 males in the United States are affected [1]. Dystrophin is a critical, large scaffolding protein in the dystrophin-glycoprotein complex found at the sarcolemma of skeletal muscle [1]. The complex helps maintain sarcolemma integrity and stability during muscle contractions by coupling the extracellular matrix proteins to the intracellular cytoskeleton in skeletal muscle [1]. Loss-of-function mutations in the dystrophin protein affect all skeletal muscle found throughout the human body. The 427 kD protein is also present in cardiac muscle, the brain, and peripheral nerves, thus affecting these tissues over time, as well [1]. One theory suggests the weakened stability of the dystrophin-glycoprotein complex when dystrophin is not expressed results in transient membrane tears during contraction, which permit pathological calcium influx [1]. Damaged skeletal muscle results in repair and regeneration of the tissue however, continual damage over time (referred to as muscle wasting) results in extensive fibrosis and loss of muscle fibers. The purpose of this thesis is to provide a comprehensive review on several molecular mechanisms that underlie Duchenne muscular dystrophy and to investigate current treatments and propose potential therapeutic targets for future research.
11
Skyrme, Sarah Louise. "Research decisions : living with Duchenne muscular dystrophy". Thesis, University of Newcastle upon Tyne, 2014. http://hdl.handle.net/10443/2678.
Testo completoAbstract (sommario):
Duchenne muscular dystrophy (DMD) is a severe form of muscular dystrophy that affects males. Muscle deterioration leads to increasing levels of disability during childhood and adolescence, with death commonly occurring in the late teens or early twenties, although changes in care and treatment are leading to increasing numbers of boys with DMD living into adulthood. Parents and parent-led charities are raising funds to find effective treatments and a cure, and much of the medical research they promote requires the participation of those with DMD. This raises questions about children and young people’s involvement in research, including their role and approach to consent and how willing they are to be involved in the medical research their parents and DMD charities advocate. Through qualitative interviews with nine boys and young men with DMD and one young woman with muscular dystrophy, I explored their thoughts on medical research and the broader issue of how they live and cope with their condition. As part of this discussion I examined how they might make a decision to participate in medical research, focusing on the processes, interactions and individuals they consider important in helping them to decide. My approach privileges the participants’ thoughts and opinions, positioning them as able social actors (James & Prout 1997) who can provide insight into their experiences. Currently little is known about the lives of children and young people with a significant, degenerative disability, particularly around their thoughts on medical research participation and decision-making (Dixon-Woods 2006). The views of my participants provide the basis for this research, with work from the sociology of childhood and from disability studies informing and contextualising it. The way in which parents are involved in daily life is discussed to gain an understanding of how the participants work with those they trust. This relationship may provide understandings of how decisions are influenced by family input and how support assists those who are young and have a degenerative condition. It is possible that this model of working with the significant people in their lives promotes agency and independence, aiding the participants towards, rather than away from autonomy.
12
Abmayr, Simone. "Gene therapy for muscular dystrophy using secondary modifiers of the dystrophic phenotype". [S.l.] : [s.n.], 2005. http://deposit.ddb.de/cgi-bin/dokserv?idn=973452595.
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13
Dunant, Patrick. "Strategies for Molecular Therapy of Duchenne Muscular Dystrophy". Diss., lmu, 2003. http://nbn-resolving.de/urn:nbn:de:bvb:19-12429.
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14
Bia, Britta Lydia. "Cardiomyopathy in mouse models of Duchenne muscular dystrophy". Thesis, University of Oxford, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.301799.
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15
Winnard, Alissa Vira. "Exception patients in Duchenne and Becker muscular dystrophy /". The Ohio State University, 1993. http://rave.ohiolink.edu/etdc/view?acc_num=osu1487847309050842.
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16
Fusto, Aurora. "Genetic and clinical modifiers in Duchenne muscular dystrophy". Doctoral thesis, Università degli studi di Padova, 2019. http://hdl.handle.net/11577/3423193.
Testo completoAbstract (sommario):
La distrofia muscolare di Duchenne (DMD) è una malattia neuromuscolare causata da mutazioni del gene codificante per la distrofina (DMD) che ne impediscono la produzione. Sebbene tutti i pazienti affetti da DMD condividano lo stesso difetto biochimico di distofina, a livello fenotipico è osservabile una grande varietà in termini di progressione della malattia, ad esempio nell'età di perdita della deambulazione o nell'età di insorgenza di complicanze cardiache e respiratorie. Questa variabilità è dovuta a diversi fattori, alcuni di origine ambientale (ad esempio la qualità delle cure a cui hanno accesso i malati) e altri di natura genetica, suddivisibili in cis-acting, ossia l'effetto dei diversi tipi di mutazioni nel gene DMD sul fenotipo, e trans-acting, ovvero l'effetto di SNPs modificatori sul fenotipo. Questi ultimi sono polimorfismi in geni diversi da quello causativo della malattia, che hanno però un effetto sul suo fenotipo. Usando come outcome la perdita della deambulazione sono stati individuati numerosi SNPs modificatori, quali: rs28359074 in SPP1, rs2303729, rs1131620, rs1051303 e rs10880 in LTBP4, rs1883832 e rs6074022 in CD40, rs1815739 in ACTN3, rs2725797 and rs2624259 in THBS1.
L'obiettivo del mio percorso di dottorato è stato lo studio della variabilità genetica e clinica nella distrofia muscolare di Duchenne, conducendo indagini in vitro e studi osservazionali retrospettivi.
Il primo approccio è stato utilizzato per verificare l'interazione dello SNP modificatore rs28357094 nel gene SPP1, codificante la proteina osteopontina (OPN), e il trattamento farmacologico con glucocorticoidi (nello specifico deflazacort) in mioblasti e miotubi primari derivati da controlli sani e da pazienti DMD. Lo studio ha messo in evidenza che l'osteopontina è sovraespressa in miotubi con genotipo TG per lo SNP rs28357094, rispetto a TT. Inoltre, è stato rilevato che il trattamento con Deflazacort induce l'aumento della produzione di OPN solo nei miotubi con genotipo TG. Questi risultati hanno confermato l'interazione tra il modificatore genetico e il trattamento con glucocorticoidi, sottolineando l'importanza del genotipo di rs28357094 nella risposta al trattamento farmacologico nei pazienti DMD.
Successivamente, il nostro interesse si è rivolto allo studio dell'effetto non solo degli SNPs modificatori, ma anche dell'effetto delle diverse mutazioni nel gene della distrofina (DMD) e del trattamento farmacologico sul decorso della malattia nei pazienti DMD, focalizzando la nostra attenzione su diversi aspetti fenotipici, quali: la performance degli arti superiori, la funzione respiratoria e cardiaca. L'obiettivo di questi studi, resi possibili dalla collaborazione di numerosi centri italiani nella raccolta dei dati clinici, è stato quello di evidenziare potenziali nuovi target terapeutici e di fornire importanti informazioni per la stratificazione dei pazienti nel corso dei trial clinici.
Il nostro lavoro ha permesso di confermare l'influenza di alcuni degli SNPs, noti per il loro effetto sulla perdita della deambulazione, anche su altri parametri clinici consentendoci di identificare misure di efficacia clinica nella DMD. E' stato poi possibile documentare l'effetto protettivo del trattamento con glucocorticoidi anche su aspetti della malattia non strettamente correlati alla deambulazione, come la funzionalità respiratoria e cardiaca e dimostrare come alcune mutazioni nel gene DMD abbiano effetti diversi sull'espressione del fenotipo dei pazienti.
Infine, il mio interesse si è rivolto al modelling di malattie neuromuscolari in sistemi di coltura tridimensionali, con lo scopo di far luce sui meccanismi molecolari causativi e fornire piattaforme utili per la ricerca e il test di molecole con azione farmacologica.Duchenne muscular dystrophy (DMD) is a neuromuscular disease caused by out-of-frame mutations in the DMD gene resulting in the lack of dystrophin in skeletal muscle fibres. Even though all DMD patients share the same molecular defect, it is possible to observe high variability in the disease's progression, i.e. differences in loss of ambulation age, onset of respiratory and cardiac failure. This variability is due both to environmental and genetic factors. Genetic factors may be divided in cis-acting, nominally the type of DMD mutation, and trans-acting, or modifier SNPs. These are polymorphisms in genes, different from the causative DMD, that have and effect on the phenotype. There are several modifier SNPs known to alter age at loss of ambulation. These are: rs28359074 in SPP1, rs2303729, rs1131620, rs1051303 e rs10880 in LTBP4, rs1883832 e rs6074022 in CD40, rs1815739 in ACTN3, rs2725797 e rs2624259 in THBS1. The main goal of my PhD was the study of clinical and genetic variability in DMD, through in vitro and observational retrospective studies. We carried an in vitro research to verify the interaction of rs28357094 in SPP1, that codifies for osteopontin (OPN), and glucocorticoids treatment (Deflazacort) in primary myoblasts and myotubes derived from healthy individuals and DMD patients. We found that OPN is overexpressed in rs28357094 TG genotype myotubes, compare to TT genotype. Moreover, deflazacort treatment induces an increase in OPN production in TG myotubes. These results confirmed the interaction between rs28357094 and glucocorticoids treatment. Afterwards, we studied the effect of the known modifiers, on multiple phenotypic aspects: upper limbs performance, respiratory and cardiac function. These analyses had been made possible thanks to the collaboration in the data collection phase of several Italian centres. Our goals were to find new potential therapeutic targets and to provide information useful for patients stratification in clinical trials. We were able to confirm the effect of some SNPs, known to be modifier of age at loss of ambulation, on diverse outcomes measures as performance of upper limbs, respiratory and cardiac function. Furthermore, we assess the protective effect of glucocorticoids treatments on diseases aspects other than ambulation, and provide new information about the correlation between DMD mutations and phenotype severity. Finally, I switched my interest to three-dimensional modelling of neuromuscular diseases, aiming to clarify pathological mechanisms and provide a versatile platform for drug screening and test.
17
Judge, Luke Milburn. "Dissecting the signaling and mechanical functions of the dystrophin-glycoprotein complex in skeletal muscle /". Thesis, Connect to this title online; UW restricted, 2006. http://hdl.handle.net/1773/4989.
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18
Pearce, Marcela. "Genomic structure of the human utrophin gene". Thesis, University of Oxford, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.318897.
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19
Woolf, Peter James. "Cardiac calcium handling in the mouse model of Duchenne Muscular Dystrophy". University of Southern Queensland, Faculty of Sciences, 2003. http://eprints.usq.edu.au/archive/00001525/.
Testo completoAbstract (sommario):
The dystrophinopathies are a group of disorders characterised by cellular absence of the membrane stabilising protein, dystrophin. Duchenne muscular dystrophy is the most severe disorder clinically. The deficiency of dystrophin, in the muscular dystrophy X-linked (mdx) mouse causes an elevation in intracellular calcium in cardiac myocytes. Potential mechanisms contributing to increased calcium include enhanced influx, sarcoplasmic reticular calcium release and\or reduced sequestration or sarcolemmal efflux. This dissertation examined the potential mechanisms that may contribute to an intracellular calcium overload in a murine model of muscular dystrophy. The general cardiomyopathy of the mdx myocardium was evident, with the left atria from mdx consistently producing less force than control atria. This was associated with delayed relaxation. The role of the L-type calcium channels mediating influx was initially investigated. Dihydropyridines had a lower potency in contracting left atria corresponding to a redued dihydropyridine receptor affinity in radioligand binding studies of mdx ventricular homogenates (P<0.05). This was associated with increased ventricular dihydropyridine receptor protein and mRNA levels (P<0.05). The function of the sarcoplasmic reticulum in terms of release and also sequestration of calcium via the sarco-endoplasmic reticulum ATPase were investigated. A lower force of contraction was evident in mdx left atria in response to a range of stimulation frequencies (P<0.05) and concentrations of extracellular calcium (P<0.05). However, in the presence of 1 nM Ryanodine to block sarcoplasmic reticular calcium release, increased stimulation frequency caused similar forces to those obtained in control mice suggesting enhanced calcium influx via L-type calcium channels in mdx. Rapid cooling contractures showed a reduced contracture in mdx compared to control in response to cooling. This suggests some dysfunction in SR storage, which may be associated with the delayed relaxation time. Concentration-response curves to inhibitors of the sarco-endoplasmic reticulum showed no difference in function of the enzyme responsible for calcium uptake into the sarcoplasmic reticulum. Although sarco-endoplasmic reticulum ATPase mRNA was upregulated, no functional benefit was evident. This study indicates that a deficiency of dystrophin leads to upregulation of L-type calcium channels that contribute to increased calcium influx, with no functional change in sarcoplasmic reticular sequestration. Upregulation of the influx pathway is a potential mechanism for the calcium overload observed in mdx cardiac muscle.
20
Johansson, Camilla. "Exploring genotype to phenotype correlations in Duchenne muscular dystrophy". Thesis, KTH, Skolan för bioteknologi (BIO), 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-215302.
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21
Roberts, Thomas C. "Duchenne muscular dystrophy : RNA-based therapeutics and microRNA biology". Thesis, University of Oxford, 2012. http://ora.ox.ac.uk/objects/uuid:f53ea1f3-92db-4f90-ba95-01f2a56eae8f.
Testo completoAbstract (sommario):
Duchenne muscular dystrophy (DMD) is a progressive muscle wasting disorder caused by absence of functional dystrophin protein. This thesis describes investigations into the role of small non-coding RNAs in both DMD pathology, and as potential therapeutic molecules. MicroRNAs (miRNAs) are a class of small RNAs that regulate gene expression and are implicated in wide-ranging cellular processes and pathological conditions. This study has compared differential miRNA expression in proximal and distal limb muscles, diaphragm, heart and serum in the mdx dystrophic mouse model relative to wild-type controls. Global transcriptome analysis revealed muscle-specific patterns of differential miRNA expression as well as commonalities between tissues, including previously identified dystromirs. miR-1, miR-133a and miR-206 were found to be highly abundant in mdx serum, suggesting that these miRNAs are promising disease biomarkers. Indeed, the relative serum levels of these miRNAs were normalised in response to peptide-PMO mediated dystrophin restoration therapy. This study has revealed further complexity in the miRNA transcriptome of the mdx mouse, an understanding of which will be valuable for the development of novel DMD therapeutics and for monitoring their efficacy. Myostatin is a secreted growth factor that negatively regulates muscle mass and is therefore a potential pharmacological target for the treatment of muscle wasting disorders such as DMD. This study describes a novel myostatin inhibition approach in which small interfering RNAs (siRNAs) complementary to a promoter-associated transcript induce transcriptional gene silencing (TGS) in cultured myotubes. Silencing was sensitive to treatment with the histone deacetylase inhibitor Trichostatin A, and the silent state chromatin mark H3K9me2 was enriched at the myostatin promoter following siRNA transfection, suggesting epigenetic remodelling underlies the silencing effect. These observations suggest that long-term epigenetic silencing may be feasible for myostatin and that TGS is a promising novel therapeutic strategy for the treatment of muscle wasting disorders. The work in this thesis therefore demonstrates the potential of small RNAs as therapeutic agents and as disease biomarkers in the context of DMD.
22
Geisemeyer, Sarah. "Duchenne muscular dystrophy : a genetic, cognitive and psychosocial approach". Thesis, Kingston University, 2017. http://eprints.kingston.ac.uk/40678/.
Testo completoAbstract (sommario):
Duchenne muscular dystrophy (DMD) is a severe, progressive muscle wasting disorder that affects 1 in 3600 male births. It is caused by genetic mutations in the dystrophin gene. This study investigated several aspects of the neuromuscular disorder within a population of Brazilian DMD boys and their families. This study's framework was laid out within the prism of an interacting cycle of genetic factors, cognitive functioning, and psychosocial aspects that underlie the neuromuscular disorder. It focuses on DMD's aetiology, history and previous research on genetic, cognitive and psychosocial aspects. Mixed methods were adopted to allow for a more encompassing view of the neuromuscular disorder: cognitive tests, an emotion recognition battery, genetic analyses, well-being questionnaires, and interviews were applied. Correspondent, quantitative and qualitative data analysis was carried out. The findings of 32 DMD patients (mean age 10.4 years, SD= 2 years) and 31 control subjects (mean age 9.4 years, SD= 3 years) revealed severe cognitive dysfunctioning in all assessed cognitive domains in the DMD population, as well as in the ability of emotion recognition. In the DMD group, it could be shown that poor executive functioning stood in a positive correlation with a poor ability of emotion recognition. The DMD patients' cognitive phenotypes were correlated with the genetic mutations in their dystrophin gene, but no relationship between the patients' genotype and cognitive phenotype could be confirmed. These results were contrary to previous research, which suggested that specific mutations in the dystrophin gene cause cognitive impairment. The DMD group scored poorly on the emotion recognition task, which is also a characteristic of autism spectrum disorder. However, when diagnosing for autistic characteristics through means of an interview, only a few similarities between the two disorders could be found. In order to assess the psychosocial components that come along with the disorder, well-being questionnaires were supplied. Interestingly, DMD boys scored higher on well-being than the boys in the control group. Moreover, 30 of the DMD caregivers (mean age app. 31 years) also revealed high levels of well-being, which correlated positively with the well-being of their sons, suggesting high levels of resilience. Given the participants' socio-economic hardship and the lack of governmental help, it was concluded that participants showed an incredible level of resilience that most likely resided within their faith, which nearly all of them stated to be the reason for their strength to strive. The relevant and new information about cognitive, genetic and social aspects of DMD uncovered in this study will pave the way for further (and much needed) studies into psychosocial aspects of the disorder.
23
Buser, Karen N. Kamiri. "Parental Attitudes Regarding Newborn Screening for Duchenne Muscular Dystrophy". Case Western Reserve University School of Graduate Studies / OhioLINK, 2011. http://rave.ohiolink.edu/etdc/view?acc_num=case1307627473.
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24
Reza, Mojgan. "Engineering and optimisation of mini-dystrophin constructs for Duchenne muscular dystrophy gene therapy". Thesis, University of Newcastle upon Tyne, 2015. http://hdl.handle.net/10443/2827.
Testo completoAbstract (sommario):
Muscular dystrophies (MDs) are inherited disorders characterised by muscle weakness and atrophy. One of the most severe forms is Duchenne muscular dystrophy (DMD) which together with the milder allelic form Becker muscular dystrophy (BMD) are known as the dystrophinopathies and result from defects in the X-linked gene encoding dystrophin. Dystrophin is a structural protein of the muscle that connects the internal cytoskeleton of muscle fibres to the extracellular matrix. DMD is also amongst the most common forms of muscular dystrophy, affecting ~1 in 4000 live male birth and manifests as rapidly progressive muscle degeneration leading to loss of ambulation and death in the second or third decade from respiratory or cardiac failure. Currently, there is no cure for this devastating disease. Clinical management of symptoms and complications is limited to stabilising the condition, slowing deterioration over time and palliative care. Since discovery of the DMD gene in 1986, researchers have dedicated substantial effort into vector technologies, facilitating the use of gene therapy to reintroduce a functional copy of the dystrophin gene into muscle fibres, a potential approach to treat DMD patients. However, this approach poses additional challenges relative to many gene therapy approaches since the full-length dystrophin cDNA is ~14 kb, exceeding the packaging capacity of most viral vectors. A number of large internal in-frame dystrophin deletions have been identified in patients that produce a relatively mild phenotype with later age of onset and a slower rate of disease progression than classical DMD. This observation has inspired the construction of internally truncated, but largely functional versions of dystrophin suitable for gene transfer using viral vectors. So far the most widely used miniaturised dystrophin transgenes have been tested in AAV-mediated gene delivery which has identified several limitations indicating the use of more favourable transgenes that have smaller deletions, yet carrying more functional parts of dystrophin. In this study human mini-dystrophin constructs of 4.3-7.7 kb in size were designed that retain key functional elements of dystrophin molecule and their relative functionality investigated in mdx mice. The ultimate aim of this study is the characterisation and optimisation of these mini-dystrophin constructs for gene delivery studies via viral vectors as a therapeutic tool for treatment of Duchenne muscular dystrophy.
25
Moura, Maria Clara Drummond Soares de. "Alterações atencionais na distrofia muscular de duchenne". Universidade de São Paulo, 2009. http://www.teses.usp.br/teses/disponiveis/47/47135/tde-31072009-151351/.
Testo completoAbstract (sommario):
A Distrofia Muscular de Duchenne (DMD) é uma doença de herança genética recessiva que gera um quadro de fraqueza muscular progressiva muitas vezes associada à deficiência mental. A atenção, considerada como o mecanismo cerebral que permite o processamento de uma informação em detrimento de outras, poderia estar alterada na doença contribuindo pelo menos em parte para o comprometimento cognitivo global observado. OBJETIVO: Investigou-se o desempenho atencional de meninos portadores de DMD utilizando-se testes psicofísicos específicos. MÉTODOS: Testou-se 30 meninos com DMD (GD) e 30 meninos saudáveis (GC), com idade entre 10 e 16 anos, em uma tarefa de tempo de reação de escolha, que consistia em responder o mais rapidamente possível a um estímulo alvo visual lateralizado com mão do mesmo lado. Antes do aparecimento deste estímulo, orientava-se a atenção automática do participante por meio de um estímulo visual periférico não-informativo espacialmente ou então sua atenção voluntária, por meio de um estímulo visual central que informava o local de maior probabilidade de aparecimento do estímulo alvo. RESULTADOS: Os tempos de reação (TR) foram maiores para o GD do que para o GC tanto no teste de atenção automática (p<0,001) quanto no teste de atenção voluntária (p<0,001). Os TR no teste de atenção voluntária foram menores do que no teste de atenção automática no caso do GD (p<0,001) mas não no caso do GC (p=0,20). O efeito atencional (diferença entre o TR na condição oposta/inválida e o TR na condição mesma/válida) não diferiu entre os dois grupos no caso da atenção automática (p=0,846), mas foi maior no GD do que no GC no caso da atenção voluntária (p<0,001). Não foram observadas quaisquer assimetrias interlaterais. DISCUSSÃO: Os resultados sugerem que os meninos com DMD apresentam prejuízo na capacidade de orientar a atenção no tempo e também gerenciam de modo anômalo para a idade a atenção espacial voluntária. O grande efeito atencional apresentado por eles é compatível com um atraso na maturação do seu sistema atencional.OBJECTIVE: Considering the divergence in the literature regarding the base of the cognitive deficits in Duchenne Muscular Dystrophy (DMD) patients, the objective of this work was to investigate their attention performance using psychophysical tests. METHODS: 25 boys with DMD (GD) and 25 healthy boys (GC), which were 10 to 16 years old, were tested in a choice reaction time task. They were instructed to respond as fast as possible to a lateralized visual target stimulus with the same side hand. Attention was automatically oriented by a peripheral spatially non-informative prime stimulus or, alternatively, voluntarily oriented by a central spatially informative cue. RESULTS: Reaction times (RT) were higher for GD than for GC in both automatic attention (p<0,001) and voluntary attention tests (p<0,001), as expected. RTs in voluntary attention tests were smaller than on automatic attention tests for GD (p<0,001) but not for GC (p=0,200). The attentional effect (difference between RT in the opposite/invalid condition and RT in the same/valid condition) was found not to differ between the two groups in the case of automatic attention (p=0,846); however it was greater for GD than for GC in the case of voluntary attention (p<0,001). Interlateral asymmetries have not been observed. CONCLUSION: These results suggest that patients with DMD are less efficient to allocate both automatic and voluntary attention. The lack of the expected motor preparation by the patients when the peripheral prime stimulus was used suggests a disturbance of temporal attention. The larger cost and benefit observed when the endogenous visual cue was used suggests a delay in maturation of the executive functions necessary to adequately allocate voluntary attention.
26
Lekan, Jaimy Marie. "Exercise-induced mechanisms of muscle adaptation in mdx mice". The Ohio State University, 2004. http://rave.ohiolink.edu/etdc/view?acc_num=osu1095372379.
Testo completo
27
Burkhardt, Katinka. "Generation of a tailored pig model of Duchenne muscular dystrophy". Diss., lmu, 2012. http://nbn-resolving.de/urn:nbn:de:bvb:19-142430.
Testo completo
28
Thomas, Karen. "The mdx mouse as a model for Duchenne muscular dystrophy". Thesis, University of Cambridge, 1991. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.386990.
Testo completo
29
Terry, Rebecca Louise. "Modification of skeletal muscle phenotype to treat Duchenne muscular dystrophy". Thesis, Royal Veterinary College (University of London), 2013. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.618307.
Testo completo
30
HARNOIS, MELISSA. "ANALYSIS OF MYOGENIC MARKERS IN DUCHENNE MUSCULAR DYSTROPHY CELL MODELS". Thesis, The University of Arizona, 2016. http://hdl.handle.net/10150/612963.
Testo completoAbstract (sommario):
The goal of this study is to compare the in vitro differentiation potential of Duchenne Muscular
Dystrophy (DMD) and non-diseased patient-derived skeletal muscle myoblasts during
myogenesis. The differentiation and fusion of myoblasts into multinucleate myotubes and the
maturity of these myotubes was assessed based on morphology, immunohistochemistry (IHC)
analysis of myotubes, as well as transcript profiles of myogenic markers. Human skeletal muscle
myoblasts derived from three non-diseased and three DMD human patients were evaluated in
multiple time course studies. Morphological evaluation as well as IHC analysis indicated that the
DMD patient-derived myoblasts have diminished capacity to differentiate and form mature
myotubes. Gene expression profiling also revealed significantly reduced basal transcript levels of
myogenic markers in DMD patient-derived cells as well as the impaired induction of these
transcripts during differentiation.
31
Wells, Kim Elizabeth. "Optimisation of constructs for gene therapy of Duchenne muscular dystrophy". Thesis, Imperial College London, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.392669.
Testo completo
32
Al-khalidi, Rasha. "P2RX7 purinoceptor as a therapeutic target in Duchenne muscular dystrophy". Thesis, University of Portsmouth, 2017. https://researchportal.port.ac.uk/portal/en/theses/p2rx7-purinoceptor-as-a-therapeutic-target-in-duchenne-muscular-dystrophy(7560e450-c050-41a0-a3a5-553ed42d6710).html.
Testo completoAbstract (sommario):
Duchenne muscular dystrophy (DMD) is the most common inherited muscle disease in men and currently there is no effective treatment for this debilitating and lethal disorder. Although the absence of dystrophin is identified as the main cause of DMD, multiple secondary changes have been found to result from the dystrophin deficiency both in muscle and in non-muscle tissues. Among these abnormalities, our laboratory and others have demonstrated a dramatic increase in the expression of the P2RX7 receptor in cells and tissues from DMD patients and the mdx mouse model of DMD. The aim of this study was to determine the effects of P2RX7 ablation on biological functions in mdx muscle in situ and to identify suitable diagnostic and prognostic biomarkers for use in studies on the pharmacological inhibition of P2RX7. RNA transcription was profiled in muscle from wild-type and mdx mice, and also from double knock-out mdx/P2rx7-/- mice which lack both functional Dmd and P2rx7 genes, and the effects of P2RX7 antagonists were assessed on pathological markers at the acute disease stage of disease in mdx mice, which resembles the human pathology. RNA sequencing was performed using the Illumina HiSeq 2000 platform to characterise the differential gene expression in tibialis anterior (TA) muscles from four week old wild type, mdx and mdx/P2rx7-/- mice. The biological functions and molecules that are most affected in mdx and corrected in mdx/P2rx7-/- tissues are those of the immune response, including the innate immune response, cytokine regulatory genes and the NF-кB pathway followed by fibrosis, telomerase regulatory genes, atherosclerosis signalling and the LXR/RXR activation pathway. Moreover, activation of the cell cycle, mitochondrial dysfunction, apoptosis and the adherens junction genes were found to be altered in mdx compared to wild type but not normalised in mdx/P2rx7-/- muscles. This analysis also demonstrated that the mdx mutation disrupts the non-sense-mediated RNA decay and splicing mechanisms, which leads to an increase in out-of-frame transcripts that may have unexpected cellular impact. One of these altered transcripts, Bmp7, was significantly down-regulated in the mdx myoblasts, myofibres and in TA muscles and restored to the normal level in mdx/P2rx7-/- muscle. Different analyses were used to map this alteration to the 5'exons of Bmp7 but the identification of this abnormal transcript was not successful. Four P2RX7 antagonists (oxidised ATP, A438079, AFC-5128 and azidothymidine (AZT)) were administered to male mdx mice and their effects on the pathology were analysed using different methods and biomarkers. All of the antagonists inhibited P2RX7 receptor-mediated responses in mdx mice without any detectable side effects. A438079 and AZT were found as the most effective in attenuating the wide range of the pathological features. The reduction in dystrophic features as results of ablation and antagonism the P2RX7 confirms the involvement of this purinoreceptor in the DMD pathology and making it an attractive target for a pharmacological treatment of this lethal disease. Additionally, as AZT is already in clinical use for other diseases, also in children, this drug could be relatively easily re-purposed and trialled for the treatment of DMD.
33
Bagdatlioglu, Emine. "Investigating the brain in mouse models of Duchenne muscular dystrophy". Thesis, University of Newcastle upon Tyne, 2017. http://hdl.handle.net/10443/3931.
Testo completoAbstract (sommario):
Duchenne muscular dystrophy (DMD) is an X-linked recessive muscle wasting disease caused by mutations in the DMD gene, which encodes the large cytoskeletal protein dystrophin. Alongside severe muscle pathology, one-third of DMD patients exhibit cognitive problems ranging from reduced verbal intelligence to severe autism. There is conclusive evidence that the muscle pathology exhibited by DMD patients is progressive, yet it remains unknown whether the cognitive impairments in DMD are also progressive. Previous studies have highlighted a cognitive impairment in the mdx mouse model of DMD, but no studies have investigated if this cognitive impairment worsens with age. We assessed the consequences of dystrophin deficiency on brain morphology and cognitive function in two dystrophin-deficient mouse models (mdx and Cmah-/-mdx mice). The overall project aim was to identify outcome measures to monitor central nervous system (CNS) pathology non-invasively in DMD mice. Magnetic resonance imaging (MRI) identified a total brain volume increase in DMD mice, alongside morphological changes in brain ventricles. Behavioural testing revealed a deficit in hippocampal spatial learning and memory, particularly long-term memory, in mdx mice, which appears to progressively worsen with age. Immunoblotting identified a progressive reduction of aquaporin-4 (AQP4) expression, the major water channel of the CNS, in DMD mice. Moreover, contrast enhancing MRI and Evans blue extravasation demonstrated a progressive impairment in blood-brain barrier (BBB) integrity in mdx mice. Proteomic profiling of the mdx cerebellum identified changes in expression of mitochondrial subunit complexes, suggestive of changes in mitochondrial function. Additionally, elevated levels of inflammatory markers were identified and confirmed in the mdx cerebellum. Our studies suggest that dystrophin deficiency causes a progressive cognitive impairment in mdx mice. We also present evidence showing that changes in osmotic equilibrium may be involved in the pathogenesis of DMD, with reductions in AQP4 expression and BBB disruptions. We speculate that some of the changes in the mdx cerebellar proteome, in comparison to wild type mice, iii serve as compensatory mechanisms whilst others may contribute directly to cognitive dysfunction in DMD. These results support a role for dystrophin in normal brain morphology and cognitive function.
34
Burt, Matthew. "Resveratrol as a Novel Therapeutic Agent for Treating Duchenne Muscular Dystrophy". Thèse, Université d'Ottawa / University of Ottawa, 2013. http://hdl.handle.net/10393/26273.
Testo completoAbstract (sommario):
Duchenne Muscular Dystrophy (DMD) is an x-linked neuromuscular disease that is caused by an absence of dystrophin protein, rendering skeletal muscle more susceptible to contraction-induced damage. One therapeutic strategy focuses on increasing the expression of endogenous utrophin A, a dystrophin homologue. Interestingly, slow muscle is more resistant to the dystrophic pathology and has increased utrophin A expression (Webster 1998; Gramolini 2001b). These observations led researchers to explore the therapeutic potential of stimulating the slow, oxidative myogenic program (SOMP) in the mdx context. Beneficial adaptations were seen with pharmacological activation of PPARδ and AMPK. We treated mdx mice with resveratrol (~100mg/kg/day), a putative SIRT1 activator, for 6-7 weeks and evaluated the activity of phenotypic modifiers that are known to influence the SOMP. SIRT1 activity and protein levels increased significantly, as well as downstream PGC-1α activity. There was evidence of a fibre type conversion as the treated mice had a higher proportion of the slow myosin heavy chain isoforms in both the EDL and Soleus skeletal muscles. Utrophin A protein levels showed modest, but consistent increases with resveratrol treatment. Finally, histological analysis revealed improvements in central nucleation and fibre size variability. These findings were promising, but raised the question of whether modifying the treatment regimen may result in greater therapeutic benefits. Surprisingly, we discovered that an elevated dose of 500mg/kg/day was ineffective in its promotion of the SOMP. SIRT1 was not activated and there was no change in utrophin A levels with resveratrol treatment. Taken together, this study demonstrates that resveratrol has the ability to promote the SOMP through SIRT1 and PGC-1α activation. It also highlights the importance of selecting an appropriate dose of resveratrol to maximize its effectiveness.
35
Betts, Corinne A. "Exon skipping peptide-pmos for correction of dystrophin in mouse models of duchenne muscular dystrophy". Thesis, University of Oxford, 2014. http://ora.ox.ac.uk/objects/uuid:545d586a-ad7b-4089-8537-b2677957b874.
Testo completoAbstract (sommario):
Duchenne muscular dystrophy (DMD) is a fatal, muscle-wasting disorder due to mutations/deletions in the dystrophin gene. Whilst improvements in palliative care have increased the life expectancy of patients, cardiomyopathy and respiratory complications are still the leading causes of death. A potential therapy for the treatment of DMD is antisense oligonucleotides (AOs), which modulate dystrophin pre-mRNA splicing to restore the dystrophin reading frame and generate a truncated functional protein. Conjugation of AOs to cell penetrating peptides (CPP), such as Pip5e-, significantly improves delivery to skeletal muscles and to the heart, which is imperative given the impact of cardiomyopathy to mortality. However, it should be noted that the contribution of skeletal muscles, such as the core respiratory muscle, the diaphragm, in dystrophic cardiopulmonary function is poorly understood. The specific aims of the work in this thesis were to (i) understand the effect of the diaphragm on cardiac function using magnetic resonance imaging (MRI), (ii) screen a number of derivatives of Pip5e (Pip6) in an effort to discover further promising peptides and define the properties integral to heart penetrating capacity, and (iii) assess whether Pip6-PMOs restore cardiac function (MRI) following a repeat, low dose regimen. In short, the specific restoration of dystrophin in the diaphragm of the dystrophic mouse model, the mdx mouse, did not improve cardiac function, highlighting the importance of a body-wide therapy. The screening of multiple Pip5e-PMO derivatives revealed 3 promising peptides with improved cardiac splicing capacity; however, serial deletions of amino acids from the central core resulted in the diminution of dystrophin restoration, possibly due to a reduction in hydrophobicity. Finally, the Pip6-PMO treatment regimen substantially restored dystrophin protein (28% in heart) and stabilised cardiac function, even with an increased work load. In conclusion, this study illustrates the importance of a body-wide treatment, such as the CPP strategy (Pip-PMO). These Pip-PMO conjugates demonstrate high dystrophin restoration in a number of muscles, including cardiac muscle, and have a beneficial effect on cardiac function.
36
Webster, Richard Ian School of Women & Children's Health UNSW. "Respiratory function as a measure of muscle strength in young boys with Duchenne Muscular Dystrophy". Awarded by:University of New South Wales. School of Women and Children's Health, 2003. http://handle.unsw.edu.au/1959.4/19206.
Testo completoAbstract (sommario):
AIMS: To evaluate the use of Manual Muscle Strength Tests (MMST), Timed Functional Tests (TFT) and Respiratory Function Tests (RFT) as measures of muscle strength in young boys with Duchenne Muscular Dystrophy (DMD) and specifically to evaluate the use of Peak Expiratory Flow (PEF). BACKGROUND: There is a need to measure the effect of treatments that potentially increase muscle strength in DMD. PEF may have advantages over Vital Capacity (VC) as a measure of respiratory function in young boys with DMD. METHODS: 17 boys with DMD (aged 5-10 years) were assessed regularly over one year. Assessment involved Respiratory Function Testing (PEF, VC, Forced Expiratory Volume in one second [FEV1]), Timed Functional Testing (walking 9 metres, climbing four stairs, arising from supine) and MMST. A single investigator performed MMST and TFTs. A separate investigator performed RFTs. For RFTs a percentage of predicted was calculated [PEF(%), FEV1(%), VC(%)].11/17 boys were treated with prednisolone which increases strength in DMD. RESULTS: At baseline, all boys had significant weakness. Mean (+/- SD) PEF(%) 69 +/- 13% and VC(%) 77 +/- 18% were abnormal. Baseline PEF(%) predicted correlated with MMST (P=0.003) and time to walk 9 metres (P=0.022). Baseline VC(%) correlated with MMST (P=0.049). There was a consistent statistically significant correlation between MMST and all TFTs. PEF was performed well on 80% of occasions, spirometry on 65%. Changes in PEF(%) showed statistically significant correlation with changes in all TFTs. The correlation was not statistically significant for VC(%) or FEV1(%). Prednisolone treated boys did better than those not treated. PEF, time to walk 9 metres and time to climb 4 stairs showed statistically significant improvement. The mean improvement from baseline in PEF(%) was 19 +/-14% in treated and 2 +/- 7% in untreated boys (P=0.012). CONCLUSIONS: MMST, TFTs and RFTs are valid measures of muscle strength in young boys with DMD. PEF is abnormal in young boys with DMD; correlates with other measures of strength and is sensitive to changes in strength. PEF is more easily performed than spirometry and has a role in monitoring muscle strength in young boys with DMD.
37
Parsons, Evelyn P. "Living with Duchenne muscular dystrophy : women's understandings of diability and risk". Thesis, Cardiff University, 1990. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.293022.
Testo completo
38
Taktak, Diane M. "A lightweight modular knee-ankle-foot orthosis for Duchenne muscular dystrophy". Thesis, University of Salford, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.261992.
Testo completo
39
Lloyd, Amy. "Duchenne muscular dystrophy and reproductive decision-making : implications of newborn screening". Thesis, Cardiff University, 2009. http://orca.cf.ac.uk/55904/.
Testo completoAbstract (sommario):
Newborn screening programmes once focused on identifying treatable conditions. In recent years, increasing numbers of untreatable genetic conditions have been included in newborn screening programmes, on the premise that families will benefit from the provision of information, support and reproductive choice. However, there is a paucity of research documenting families' experiences of newborn screening and the implications of screening for untreatable conditions. This study focuses on one untreatable condition, Duchenne muscular dystrophy (DMD). Using both quantitative and qualitative methods, this study explores the implications of two different diagnostic pathways for reproductive decision-making newborn screening and a later clinical diagnosis (which occurs when the child is an average age of 4.5 years). Quantitative data on reproductive behaviour were collected from 72 families 38 families who received a later clinical diagnosis (LCD) in the west of Scotland, and 34 families in Wales, who received a diagnosis through newborn screening (NBS), between 1990 and 2006. Qualitative data (in-depth interviews) were collected from a subset of 19 families to explore reproductive decision-making 8 families from the LCD cohort, and 11 families from the NBS cohort. The quantitative data highlighted varied effects of providing families with an earlier awareness of risk. Families in the newborn screening cohort were more likely to continue family building, and significantly more likely to use prenatal testing (p=0.05). However, there was no association between carrier risk and reproductive behaviour and little difference in the number of second affected boys. Participants in the qualitative interviews were often ambivalent about the provision of reproductive choice. Mothers' descriptions of the importance of "choice" were juxtaposed against accounts of "ignorant bliss", profound appreciation of the "carefree years", and relief at the avoidance of "difficult decisions". The medical information provided to families was often perceived to lack experiential validity. In addition, few families felt supported. The findings suggest a need for greater consideration of the true value of providing information, "choice" and support.
40
Xu, Ying. "Dynamic Regulation of Cardiac Contractility & Cardiomyopathy in Duchenne Muscular Dystrophy". The Ohio State University, 2011. http://rave.ohiolink.edu/etdc/view?acc_num=osu1306518289.
Testo completo
41
Chadwick, Jessica Ann. "Mineralocorticoid Receptors: A Novel Therapeutic Target for Treating Duchenne Muscular Dystrophy". The Ohio State University, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=osu1468946734.
Testo completo
42
Blubaugh, Victoria G. "Self-concept in siblings of chronically ill children : Duchenne muscular dystrophy /". The Ohio State University, 1986. http://rave.ohiolink.edu/etdc/view?acc_num=osu1487265555440494.
Testo completo
43
Hogarth, Marshall William. "α-Actinin-3: a novel genetic modifier of duchenne muscular dystrophy". Thesis, The University of Sydney, 2013. http://hdl.handle.net/2123/10458.
Testo completoAbstract (sommario):
Homozygosity for a common null polymorphism (R577X) in the ACTN3 gene results in deficiency of the fast muscle fiber protein, α-actinin-3, in ~18% of the world’s population. ACTN3 genotype significantly influences muscle performance in elite athletes and in the general population. There is also considerable inter-patient variability in Duchenne muscular dystrophy (DMD), some of which is caused by the modifying effects of genes independent of the causative mutation in dystrophin. On this basis, we tested ACTN3 as a genetic modifier of DMD. Here we show that α-actinin-3 deficiency significantly reduces muscle strength in both mdx mice and XX patients, providing strong evidence for ACTN3 as a genetic modifier of DMD. We also show that α-actinin-3 deficiency protects against stretch-induced damage and slows the accumulation of branched fibres in aged mdx muscle, suggesting an amelioration of disease progression. Slow muscle fibres are known to be relatively spared from the pathogenesis of DMD, and we demonstrate a shift towards a slow twitch muscle phenotype in Actn3 KO mdx muscle. In particular the shift towards aerobic metabolism, caused by increased activity of calcineurin and AMP-activated protein kinase, protects α-actinin-3 deficient muscle against the progression of dystrophic pathology in mdx mice. Genetic modifiers have immediate importance in the stratification and analysis of results of therapeutic trials and have the potential to provide insight into the molecular pathogenesis of DMD. Our studies in Actn3-/- mdx mice suggest that α-actinin-3 deficiency is detrimental to muscle performance in DMD at baseline, but ameliorates the progression of dystrophic pathology over time.
44
Laws, Nicola. "Characterisation and strategic treatment of dystrophic muscle". University of Southern Queensland, Faculty of Sciences, 2005. http://eprints.usq.edu.au/archive/00001457/.
Testo completoAbstract (sommario):
The mdx mouse is widely used as a model for Duchenne Muscular Dystrophy, a fatal X-linked disease caused by a deficiency of the sub-sarcolemmal protein, dystrophin. This dissertation reports characterisation of the features of dystrophy in the mdx mouse, including parameters such as electrophysiological and contractile properties of dystrophic cardiac tissue, quantitative evaluation of kyphosis throughout the mdx lifespan, and contractile properties of respiratory and paraspinal muscles. Following these characterisation studies, the efficacy of antisense oligonucleotides (AOs) to induce alternative mRNA splicing in mdx skeletal muscles (diaphragm and paraspinal muscles) was evaluated. The left atria of younger (<6 weeks) and older (>15 months) mdx mice showed consistently lower basal forces and responsiveness to increased calcium, while action potential duration was significantly shorter in young mice (3 weeks) and older mice (9 and 12 months) (P<0.05). Cardiac fibrosis increased with age in mdx atria and ventricles and was elevated in young (6-8 weeks) and old (15 months) mdx compared to control mice (P<0.01). This study provided insights into DMD cardiomyopathy, and suggested that very young or old mdx mice provide the most useful models. Mdx mice show thoracolumbar kyphosis like boys with Duchenne Muscular Dystrophy. A novel radiographic index, the Kyphotic Index (KI), was developed and showed that mdx mice are significantly more kyphotic from 9 months of age, an effect maintained until 17 months (P<0.05). At 17 months, the paraspinal and respiratory muscles (latissimus dorsi, diaphragm and intercostal muscles) are significantly weaker and more fibrotic (P<0.05). Administration of AOs at four sites within the diaphragm at 4 and 5 months of age significantly increased twitch and tetanic forces compared to sham treated mdx (P<0.05). However, no difference in collagen was evident and dystrophin was not detected, possibly due to the low concentration of AO utilised. This study suggested that AOs can provide functional improvement in treated skeletal muscles. Monthly injections with AOs into the paraspinal muscles from 2 months to 18 months of age alleviated kyphosis, without significantly altering twitch and tetanic forces of latissimus dorsi, diaphragm and intercostal muscles. There was evidence of less fibrosis in diaphragm and latissimus dorsi muscles (P<0.05) and reduced central nucleation of the latissimus dorsi and intercostal muscles (P<0.05). Again, dystrophin was not detected by immunoblot. These studies indicate that very young and old mdx mice display previously uncharacterised dystrophic features, and are useful models for testing new therapies such as AOs. Low doses of AOs were shown to be safe and efficacious for long-term use, however there remains a need for testing higher concentrations and improved delivery strategies.
45
Al-Rewashdy, Hasanen. "Determining the Contribution of Utrophin A Versus Other Components of the Slow, Oxidative Phenotype in the Beneficial Adaptations of Dystrophic Muscle Fibers Following AMPK Activation". Thesis, Université d'Ottawa / University of Ottawa, 2014. http://hdl.handle.net/10393/31470.
Testo completoAbstract (sommario):
Duchenne Muscular Dystrophy (DMD) results from the absence of a functional dystrophin protein. Among its possible therapeutic options is the upregulation of dystrophin’s autosomal analogue, utrophin A. This can be achieved by a pharmacologically induced shift towards a slower, more oxidative skeletal muscle phenotype, which has been shown to confer morphological and functional improvements on models of DMD. Whether these improvements are a result of the utrophin A upregulation or other beneficial adaptations associated with the slow, oxidative phenotype, such as improved autophagy, has not been determined. To understand the importance of utrophin A to the therapeutic value of the slow, oxidative phenotype, we used the utrophin/dystrophin double knockout (dKO) model of DMD. We found the dKO mouse to have a similar skeletal muscle signaling capacity and phenotype to mdx mice. When treated with the adenosine monophosphate activated protein kinase (AMPK) agonist 5-aminoimidazole-4-carboxamide-1-β-D-ribofuranoside (AICAR), both dKO and mdx mice expressed a shift towards a slower, more oxidative phenotype. In the mdx mice, this shift caused improvements in muscle fiber central nucleation, IgM penetration, damage from eccentric contractions, and forelimb grip strength. These morphological and functional benefits were not seen in the AICAR treated dKO mice. This study highlights the importance of utrophin A upregulation to the benefits of the slow, oxidative myogenic program to dystrophic mice. It confirms utrophin A as a therapeutic target in DMD and the slow, oxidative myogenic program as clinically relevant avenue towards treatment of the disease.
46
Deol, Jatinderpal. "Development of helper-dependent adenovirus for gene expression in muscle". Thesis, McGill University, 2001. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=33745.
Testo completoAbstract (sommario):
Duchenne muscular dystrophy (DMD) is characterized by necrosis and progressive loss of muscle fibers. DMD patients have a mutation in the gene encoding dystrophin, a large membrane-associated cytoskeletal protein on the cytoplasmic side of the sarcolemma. Gene therapy using fully deleted adenoviral vectors shows great potential for the eventual treatment of DMD and other genetic diseases. These vectors are less immunogenic than their predecessors and have the capacity to carry large DNA inserts such as the full-length dystrophin (12 kb). However, the lack of viral genes results in a weakened and subsiding (short) transgene expression in muscle. Findings in the lung and liver have shown the adenoviral E4 region, in particular E4 open reading frame 3 (ORF3) to contribute to the maintenance of transgene expression. We constructed an adenovirus in which E4 ORF3 was reintroduced into a fully-deleted adenovirus along with full-length dystrophin (AdCBDysORF3). Dystrophin levels produced by AdCBDysORF3 were found to be not sustained in mdx mice, dropping significantly by day 90. However, expression levels did increase when AdCBDysORF3 was complemented with other viral proteins such as EIB. Likewise, increasing the expression of the primary adenovirus receptor (CAR) in muscle also resulted in a higher initial dystrophin expression in myofibers.
47
Turner, Sally Ann. "Analysis of dystrophic mdx muscle following the implantation of normal dermal fibroblasts". Thesis, Imperial College London, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.271623.
Testo completo
48
Thanh, Le Thiet. "Exon-specific monoclonal antibodies against dystrophin". Thesis, University of Salford, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.261661.
Testo completo
49
Hoskin, Janet Ann. "Seeing beyond the wheelchair : learning and behaviour issues and intervention in Duchenne Muscular Dystrophy". Thesis, Swansea University, 2011. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.678285.
Testo completo
50
Wang, Qiong. "The activity and content of calpains in maturing dystrophic muscle membranes". Thesis, Virginia Tech, 2005. http://hdl.handle.net/10919/42729.
Testo completoAbstract (sommario):
Increased calcium-activated calpain proteolysis in the sarcolemma membrane is thought to be a primary mechanism in the pathophysiology of Duchenne Muscular Dystrophy (DMD). However, few studies have tested this possibility prior to the overt signs of the dystrophy. The purpose of this study was to test the hypothesis that there is greater calpain content and total relative calpain activity in membranes obtained from dystrophic (mdx; mdx:utrophin-deficient (mdx:utrn-/-)) compared to wildtype (wt) mouse skeletal muscles during maturation at ages 7- and 21-d,and at a post-maturation age of 35-d. Calpain activity was determined as the calcium-dependent cleavage of the flurogenic substrate SLY-AMC, and content was determined by Western analysis with an anti-calpain antibody. There were several intriguing findings:
1. There was an inverse relationship between calpain content and relative activity in the whole muscle in both wt and mdx mice from age 7- to 35-d: calpain content decreased, and relative calpain activity increased as the mice aged. This suggests a similar role for calpain in both genotypes, which might relate to specific maturation processes, possibly up to age 21-d. Although the inverse relation was evident at 35-d, the targets for calpain in mdx compared to wt likely differed.
2. The increased relative calpain activity in the membrane fraction of mdx mice at age 35-d (26.73 Arbitrary Units, (AU)) compared to that of age 7- (4.9AU; p<0.05) and 21-d (8.74AU; p<0.05) is temporally related to degeneration and regeneration processes, and may also indicate activation of apoptosis, in mdx muscles at this age.
3. At age 7-d, there were no significant differences in either calpain content or relative calpain activity in all subcellular fractions for wt and mdx mice. This result might suggest similar calpain distribution and activities that are related to the regulation of muscle maturation and differentiation in both genotypes. (Note:data were not obtained for the mdx:utrn-/- mice at age 7-d because of insufficient animals).
4. At age 21-d, there was greater relative calpain activity in the myofibrillar supernatant fraction in mdx (15.13AU) than wt mice (1.18AU; p<0.05). This could indicate calpainâ s role in the initiation of myofibrillar protein turnover and the proteolysis of submembranous networks in the mdx muscles.
5. At age 21-d, greater calpain content in the mdx (1.40ìg) compared to wt (0.23 ìg; p<0.05) membrane fraction might suggest a broader distribution of calpain along membranes that contributes to the onset of dystrophy in the mdx muscles.
6. At age 35-d, there was greater calpain content in the mdx:utrn-/- compared to the wt membrane (0.48ìg vs 0.13 ìg), cytosolic (0.88ìg vs 0.30ìg), and myofibrillar supernatant (0.49ìg vs 0.17ìg; p<0.05 ) fractions This increased content and broad distribution across several subcellular fractions may reflect degeneration and regeneration processes, and potentially activation of apoptosis, in the mdx:utrn-/- muscles.
These data suggest that calpain activity contributes to dystrophic pathophysiology mainly in the membrane fraction of mdx skeletal muscles at age ~21-d, but appears to contribute later at 35-d and in more subcellular fractions in mdx:utrn-/- skeletal muscles.Master of Science