1,736,430 research outputs found
Cardiological evaluation of DMD gene female mutation carriers.
No full textreservedBACKGROUND: la distrofia muscolare di Duchenne (DMD) è una malattia genetica X-linked dovuta a mutazioni del gene DMD, che codifica per distrofina. La sua mancanza causa la necrosi delle cellule muscoloscheletriche la sostituzione del tessuto muscolare con tessuto fibro-adiposo. È una malattia sistemica con progressiva compromissione fisica e dalla perdita della deambulazione attorno ai 12 anni. A livello cardiaco si ha sviluppo di cardiomiopatia dilatativa che insieme alla compromissione respiratoria è responsabile del decesso del paziente. La forma lieve di DMD è la distrofia muscolare di Becker (BMD). Il cardine della terapia sono i corticosteroidi. La prognosi è migliorata nel corso degli anni grazie alla ventilazione assistita e alle terapie farmacologiche cardio-attive: attualmente l’aspettativa di vita è in media di 30-40 anni.
Le portatrici femmine di varianti del gene DMD sono di solito protette dallo sviluppo del fenotipo DMD-like per la presenza di un allele sano; tuttavia sono suscettibili allo sviluppo di complicazioni cardiache che ne accorciano comunque l’aspettativa di vita.
SCOPO DELLO STUDIO: analisi delle caratteristiche cliniche delle pazienti portatrici di varianti del gene DMD con particolare attenzione al fenotipo cardiaco; valutazione di eventuali correlazioni tra le manifestazioni neurologiche e cardiologiche.
MATERIALI E METODI: per ogni paziente si sono stati valutati età alla valutazione, anamnesi patologica remota e prossima, sintomi ed obiettività neurologica. Il protocollo cardiologico comprendeva test genetico, esame obiettivo, eventuale sintomatologia riferibile a patologia cardiaca, ECG a 12 derivazioni, ECG Holter, ecocardiogramma Color Doppler. In casi selezionati è stata eseguita risonanza magnetica cardiaca con contrasto. Le pazienti sono state divise in due gruppi in base alla presenza o meno di cardiopatia; i dati strumentali dei due gruppi sono stati poi comparati.
RISULTATI: le pazienti della coorte avevano in media 48 anni e il 76% presentava storia familiare positiva per DMD. Il 33% assumeva un qualche farmaco cardio-attivo. Si aveva inattivazione random del cromosoma X nel 55,3% del campione, mentre nel 29,8% l’inattivazione era skewed. Il 29,4% delle pazienti sono state sottoposte a biopsia muscolare che ha rivelato in tutte un mosaico di fibre distrofino-positive e negative all’immunofluorescenza. La CPK sierica era aumentata nel 79,5% delle pazienti. Il 42,6% del campione era sintomatico dal punto di vista neuromuscolare. Sono state poi studiate 47 pazienti dal punto di vista cardiaco, di cui 11 sono affette da cardiopatia. Si è visto che il 66,7% delle pazienti cardiopatiche aveva un fenotipo neurologico intermedio o severo. Le alterazioni ECG erano presenti nel 50% delle pazienti cardiopatiche; l’intervallo QRS medio delle pazienti cardiopatiche era di 108,4 ms. All’ECG Holter le pazienti cardiopatiche presentavano in media 1565,5 BEV/24h. L’ecocardiogramma mostrava ventricolo sinistro dilatato in 7 pazienti (14,9% delle pazienti) e funzione sistolica ridotta in 10 casi (24,4%). La risonanza magnetica cardiaca ha poi permesso di osservare LGE a livello della parete postero-laterale basale in 6 pazienti, di cui 2 non precedentemente diagnosticate come cardiopatiche.
CONCLUSIONI: la DMD può avere delle manifestazioni anche nelle portatrici di sesso femminile, soprattutto cardiologiche. È opportuno monitorare nel tempo le pazienti dal momento della diagnosi di variante del gene DMD. A tal fine, la risonanza magnetica potrebbe essere lo strumento diagnostico più adeguato in quanto consente di rilevare precocemente eventuali alterazioni a livello miocardico non visibili all’esame ecocardiografico
Registries versus tertiary care centers: How do we measure standards of care in Duchenne muscular dystrophy?
No full textIn Duchenne Muscular Dystrophy (DMD), large clinical trials can only be possible as part of an international multicentric effort. A crucial question for the field is whether the centers involved in clinical trials and in natural history studies have similar standards of care, so that comparability of the data is guaranteed and the risk of bias reduced
Duchenne muscular dystrophy : mutation profiling in view of the emerging gene-based therapies
No full textIncludes bibliographical references (leaves 97-115).Duchenne Muscular Dystrophy (DMD) is a lethal, X-linked, recessive muscle-wasting disorder affecting 1 in 3 500 live male births worldwide, for which only palliative care is available to date. Large exonic deletions or duplications are found in approximately 70% of DMD patients, for which diagnostic testing is available. The remaining 30% carry point mutations, which go largely undetected, as no testing is currently offered due to the great size of the DMD gene and the logistical challenges involved
A novel custom high density-comparative genomic hybridization array detects common rearrangements as well as deep intronic mutations in dystrophinopathies
No full textBackground: The commonest pathogenic DMD changes are intragenic deletions/duplications which make up to 78% of all cases and point mutations (roughly 20%) detectable through direct sequencing. The remaining mutations (about 2%) are thought to be pure intronic rearrangements/mutations or 5'-3' UTR changes. In order to screen the huge DMD gene for all types of copy number variation mutations we designed a novel custom high density comparative genomic hybridisation array which contains the full genomic region of the DMD gene and spans from 100 kb upstream to 100 kb downstream of the 2.2 Mb DMD gene.Results: We studied 12 DMD/BMD patients who either had no detectable mutations or carried previously identified quantitative pathogenic changes in the DMD gene. We validated the array on patients with previously known mutations as well as unaffected controls, we identified three novel pure intronic rearrangements and we defined all the mutation breakpoints both in the introns and in the 3' UTR region. We also detected a novel polymorphic intron 2 deletion/duplication variation. Despite the high resolution of this approach, RNA studies were required to confirm the functional significance of the intronic mutations identified by CGH. In addition, RNA analysis identified three intronic pathogenic variations affecting splicing which had not been detected by the CGH analysis.Conclusion: This novel technology represents an effective high throughput tool to identify both common and rarer DMD rearrangements. RNA studies are required in order to validate the significance of the CGH array findings. The combination of these tools will fully cover the identification of causative DMD rearrangements in both coding and non-coding regions, particularly in patients in whom standard although extensive techniques are unable to detect a mutation
wardle/dmd: v1.0.180
No full text<p><strong>Full Changelog</strong>: https://github.com/wardle/dmd/compare/v1.0.174...v1.0.180</p>
wardle/dmd: v1.0.200
No full text<p><strong>Full Changelog</strong>: https://github.com/wardle/dmd/compare/v1.0.180...v1.0.200</p>
Scaling DMD modes for modeling Dynamic Induction Control wakes in various wind speeds
No full textDynamic Mode Decomposition (DMD) is a fully data-driven method to extract a linear system from experimental or numerical data. It has proven its suitability for modeling wind turbine wakes, particularly those generated with Dynamic Induction Control (DIC), a method to reduce the wake deficit by enhancing its mixing with the surrounding flow. In this context, DMD may be used to build computationally efficient aerodynamic models suitable for model-based wind farm control algorithms. However, these standard DMD models are only valid for the flow conditions of the training data. This paper presents a novel approach to generalize a DMD model for DIC wakes from the training wind speed to various wind speeds by scaling the DMD modes. For this purpose, we first extract the DMD modes from numerical simulations of a DIC wake at a constant, homogeneous wind speed. Then, we adapt the obtained modes to a different wind speed with a scaling law for the frequency and magnitude derived from the definition of the Strouhal number. This allows for a versatile, efficient application of the DMD model in heterogeneous wind conditions at low computational costs. For validating the presented method, we model a helix wake at 6 ms-1 based on the DMD modes from Large Eddy Simulations (LES) at 9 ms-1. The DMD model coincides at a high level with validation simulations, resolving even mid- to small-scale structures.Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Team Jan-Willem van Wingerde
wardle/dmd: v1.0.170-alpha
No full text<ul>
<li>Switch to using SQLite for backing store</li>
</ul>
<p>As a consequence, this release is not compatible with databases created using previous releases. As dmd is designed to create new databases for every release, every week, this should not be an issue.</p>
ANTISENSE MEDIATED DYSTROPHIN READING FRAME RESTORATION
No full textExon skipping using antisense oligonucleotides (AONs) has successfully been used to
reframe the mRNA in various DMD (Duchenne muscular dystrophy) patients carrying
deletions and in the mdx mouse model. This study can be devided in two parts: in the
first part we have tested the feasibility of the exon skipping approach for patients with
small mutations in in-frame exons, while in the second part a quantitative comparison of
exon skipping revealing techniques is addressed.
We first identified 55 novel disease-causing point mutations. We selected 5 patients
with nonsense or frameshifting mutations in exons 10, 16, 26, 33 and 34. Wild type and
mutation specific 2‟OMePS AONs were tested in cell-free splicing assays and in
cultured cells derived from the selected patients. The results obtained confirm cell-free
splicing assay as an alternative system to test exon skipping propensity when patients‟
cells are unavailable. In myogenic cells, similar levels of exon skipping were observed
for wild type and mutation specific AONs for exons 16, 26 and 33, while for exon 10 and
exon 34 the efficiency of the AONs was significantly different. Interestingly, in some
cases skipping efficiencies for mutated exons were quite dissimilar compared to what
previously reported for the respective wild type exons. This behaviour may be related to
effect of the mutations on exon skipping propensity and highlights the complexity of
identifying optimal AONs for skipping exons with small mutations.
In the second part we compared different techniques to reveal the exon skipping levels
in the muscles of 7 different mdx mice. An absolute quantification of the dystrophin
transcript amount was possible using a digital array. Results underline the low
expression of the dytrophin gene and the amount needed to correctly quantify the exon
skipping percentage
Proteomic profiling of Duchenne muscular dystrophy : protein patterns and candidate markers of disease
No full textDuchenne muscular dystrophy (DMD) caused by mutations in the dystrophin gene is a severe chronic muscle-wasting disease leading to early loss of ambulation in patients and to death by the third decade. Other muscular dystrophies exist including amongst others DMD’s milder allelic form Becker Muscular Dystrophy and the heterogeneous group of limb-girdle muscular dystrophies differ in age of onset, severity, and affected proteins.
In diagnosing muscular dystrophies, the assessment of multiple proteins in a muscle biopsy by immunohistochemical methods is considered the gold standard, as the identification of the underlying mutation is not always feasible or sufficient. The reproducibility and sensitivity of reverse protein arrays and their excellent correlation with immunohistochemistry and immunoblotting combined with minimal sample and antibody consumption make them an ideal approach for the assessment of muscular expression of multiple proteins in small biopsies. We have evaluated a set of antibodies currently used in standard diagnostic processes for muscular dystrophies on human muscle tissue and cultured primary human myotubes and show high correlations with Western blot data and reproducible significant differences in dystrophin, sarcoglycan, and dystroglycan expression between control and patient samples. This suggests that reverse protein arrays can quantitatively measure muscle proteins in as little as 10mg muscle tissue. This technology could be of interest not only in diagnostic processes, but especially for protein quantification of multiple, follow-up biopsies during clinical trials in upcoming therapy approaches such as exon-skipping, when protein expression in muscle is considered an important outcome measure or biomarker.
Despite the precise and extensive knowledge about the dystrophin gene and its protein, precise molecular and cellular events that eventually lead to muscle fiber degeneration in DMD are poorly understood. Downstream pathogenic events in metabolic pathways and cellular signalling that are key factors causing the ultimate degeneration of muscle fibers in DMD and reflecting disease state can be elucidated using mass spectrometry-based proteomics experiment. Proteomic profiling of DMD muscle tissue and comparing the resulting pattern to other muscular dystrophies has revealed a drastic increase in the muscle-specific member of the small heat shock protein family HSPb2 and, to a lesser extent, a decrease in GPD1L that was not seen in other muscular dystrophies. We are currently implementing a set of experiments to validate HSPb2 as disease marker for duchenne muscular dystrophy in cultured primary myotubes from DMD patients and, if applicable, in serum from DMD patients. HSPb2 is a promising candidate that could be applied as signature molecule as part of a protein panel that can be used to assessed disease state in DMD or therapeutic effects of novel drugs or treatments
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