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PubMed2006

Medulloblastoma in a child with Duchenne muscular dystrophy.

MATERIALS AND METHODS: A 7-year-old boy diagnosed with Duchenne muscular dystrophy (DMD) presented with clinical features of raised intracranial tension. A CT scan revealed an enhancing vermian mass extending on to the fourth ventricle, which was excised and reported to be medulloblastoma. The patient was treated with craniospinal radiotherapy but progressed after 6 months. DISCUSSION: Neoplasms associated with DMD are rare and the present case may well be the first one with medulloblastoma. Interestingly, all neoplasms associated with DMD reported so far have been round cell tumors, which may lead to insights into their possible molecular associations.

Cerebellar Neoplasms↗
PubMed2002

Expression of tumor necrosis factor-alpha in regenerating muscle fibers in inflammatory and non-inflammatory myopathies.

The expression level of tumor necrosis factor (TNF)-alpha is elevated in idiopathic inflammatory myopathies and Duchenne muscular dystrophy (DMD), but the precise role of TNF-alpha is unknown. To elucidate the possible role of TNF-alpha, we investigated the expression of TNF-alpha and its receptor in polymyositis (PM), dermatomyositis (DM), and DMD using in situ hybridization (ISH) and immunohistochemistry. We showed that TNF-alpha mRNA and protein were present in muscle fibers. TNF-alpha-positive fibers were observed in all cases of PM, DM and DMD, but were rare or absent in neurogenic disorders and normal controls. The proportion of TNF-alpha-positive fiber showed a significant positive correlation with the proportion of regenerating fibers that were positive for the developmental form of myosin heavy chain (MHC-d). The number of TNF receptor-positive fibers was small. Some muscle fibers expressed both TNF-alpha and its receptor simultaneously. Our results indicate that TNF-alpha is produced and expressed by muscle fibers and associated with muscle regeneration.

Adolescent↗
PubMed2003

Analysis of dystrophin mRNA from skeletal muscle but not from lymphocytes led to identification of a novel nonsense mutation in a carrier of Duchenne muscular dystrophy.

Dystrophin mRNA expressed in peripheral lymphocytes of individuals with X-linked Duchenne muscular dystrophy (DMD) has been used as a source material for mutation analysis. Here we present the first report of failure of isolation of nonsense dystrophin mRNA in lymphocytes but success in skeletal muscle in a female carrier of DMD. The mutation responsible for dystrophin-negative muscle fibers of the carrier was analysed by direct sequencing of the reverse transcription PCR product of dystrophin mRNA. In her peripheral lymphocytes, no nucleotide change was detected in the 14 kb long mRNA. Remarkably, a novel nucleotide change of C1682T in exon 12, changing glutamine codon to stop codon (Q492X) was found to be present in her skeletal muscle. This change was heterozygous. Analysis of her genomic DNA disclosed heterozygous C and T nucleotides at nt 1682, confirming the genomic origin of the nonsense mutation. Although dystrophin cDNA prepared from lymphocytes was sequenced again after subcloning, mutation-retaining clone could not be isolated. This lymphocyte-specific disappearance of nonsense mRNA strongly suggested tissue-specific skewing of X-inactivation. However, both paternal and maternal dystrophin alleles were shown to be equally expressed in lymphocytes as well as in muscle, indicating no skewing of X-inactivation in lymphocytes. We concluded that the dystrophin mRNA of the DMD carrier was destabilized in lymphocytes. Our results indicated that analysis of mRNA in lymphocytes is not enough for exact carrier diagnosis of Duchenne muscular dystrophy.

Adult↗
PubMed2002

Interstitial cells of Cajal, enteric neurons, and smooth muscle and myoid cells of the murine gastrointestinal tract express full-length dystrophin.

A gene located on the X chromosome is responsible for the transcription of several mRNA and related dystrophin isoforms. Lack or truncated expression of the 427-kDa, full-length isoform in skeletal muscle results in Duchenne muscular dystrophy (DMD). Patients with DMD, as well as mdx mice, a mutant strain also lacking this isoform, show gastrointestinal dismotilities. The present aim was to identify the cell types that express full-length dystrophin in the gastrointestinal tract. An immunohistochemical study was performed using an antibody specific for this isoform, and double labelings were made for interstitial cells of Cajal (ICC) identification and to verify whether all neurons express full-length dystrophin. Three different fixation procedures were used. The results showed that ICC, enteric neurons, and smooth muscle and myoid cells expressed full-length dystrophin. In ICC and neurons, dystrophin-immunoreactive patches were irregularly distributed at the cell contour and within the cytoplasm. In smooth muscle and myoid cells, regularly spaced dystrophin-immunoreactive bars were located along the cell contour. Labeling intensity varied according to fixation procedure. The different subcellular distributions of dystrophin immunoreactivity might reflect diverse roles played by full-length isoforms in each cell type. Dystrophin loss in cells involved in gastrointestinal motility might explain the gastrointestinal symptomatology affecting DMD patients and mdx mice.

Animals↗
PubMed2003

Identification of transcripts from a subtraction library which might be responsible for the mild phenotype in an intrafamilially variable course of Duchenne muscular dystrophy.

While frame-shift mutations are usually found in Duchenne muscular dystrophy (DMD), in-frame mutations are associated with the less severe phenotype of Becker's muscular dystrophy. Exceptions have been reported in both directions suggesting the existence of modifying genes, which might be helpful for innovation of new therapeutic strategies. We report on the very rare case of an intrafamilially different course of DMD, with the younger brother being far less affected than the older one when compared at the same age. In this context, we constructed a subtraction library enriched for transcripts over-expressed in the patient with the milder phenotype. Twelve random clones were sequenced, followed by database analysis. Six of them, casein kinase 1 alpha 1, RAP2B, dynactin 3 light chain, core binding factor beta, myosin light polypeptide 2 and one hypothetical gene, were further analysed by real-time RT-PCR. All these genes were over-expressed 3-20 times in the less affected patient compared with the more severely affected one. Casein kinase 1 and the hypothetical gene showed even a slightly higher expression than the control. Up-regulation of myosin light polypeptide 2, one of the most sensitive markers of muscle fibre regeneration, obviously reflects the milder phenotype. Casein kinase 1, dynactin and core binding factor are supposed to be involved in cell cycle pathways. RAP is a component of the signalling network which controls fundamental cellular processes such as proliferation and differentiation. All four might be interesting candidates for a therapeutic approach to diminish progression of dystrophy in DMD.

Casein Kinases↗
PubMed2004

Surgical treatment of spinal deformities in Duchenne muscular dystrophy: a long term follow-up study.

BACKGROUND: Surgical treatment of spinal deformities in Duchenne muscular dystrophy (DMD) is influenced by a number of factors which have proven to be a difficult challenge. Each case should be carefully evaluated, considering not only the natural history of the spinal deformity, but also the patient's general condition. These should be thoroughly assessed through clinical and radiographic investigations together with other medical specialists. Life expectancy should be determined according to the cardio-respiratory function, and both preoperative and postoperative quality of life should be taken into consideration, trying to imagine the functional status of each patient after surgery. METHODS: From February 1985 to February 2000, 58 patients with spinal deformity in DMD were surgically treated. Of 25 patients that were operated on between 1985 and 1995, only 20 were followed-up after 5 years because 5 of them had died during this time. Therefore, the present study focuses on the results obtained in 20 cases. The 20 cases reviewed presented with a mean angular value of scoliosis equal to 48 degrees (range 10-92 degrees). Spinal fusion with our modified Luque technique [6] was performed in 19 cases, whereas CD instrumentation was applied in only one case. RESULTS: At the 5 year follow-up (range 5.6-10 years), the age ranged from 18 to 24 years and averaged 20.4 years. The postoperative angular value of scoliosis averaged 22 degrees (58%, range 0-43 degrees), the mean correction at follow-up was 28 degrees (range 0-60 degrees), and the mean loss of correction was equal to 6 degrees (range, 0-11 degrees). Vital capacity showed a slow progression, slightly inferior to its natural evolution in untreated patients. The severest complication was the death that occurred in one of the patients. CONCLUSIONS: According to the present study, an early surgery (angular value lower than 35-40 degrees) dramatically reduces the rate of risk factors associated with spinal deformities in DMD, and its advantages far exceed the disadvantages, above all in terms of quality of life.

Adolescent↗
PubMed2003

Spinal fusion in patients with Duchenne's muscular dystrophy and a low forced vital capacity.

Traditionally, spinal fusion has been denied to patients with scoliosis secondary to Duchenne's muscular dystrophy (DMD) when their forced vital capacity (FVC) is less than 30-40% of predicted values (PFVC). The reasons for this decision are a theoretically increased risk of adverse events from a prolonged anaesthetic and extensive surgery. This paper presents a retrospective analysis of 30 patients with DMD scoliosis who underwent posterior spinal fusion at the Royal National Orthopaedic Hospital. Two subgroups of patients were compared: those with more than 30% PFVC (17 patients) and those with less than 30% PVFC (13 patients). One patient in each group required a temporary tracheotomy and there were nine complications in total. The post-operative stay for patients in each group was similar (24 days in the >30% group, 20 days in the <30% group) and the complication rate was comparable with other published series. We conclude that spinal fusion can be offered to patients with DMD even in the presence of a low FVC.

Adolescent↗
PubMed2003

Gene expression profiling of Duchenne muscular dystrophy skeletal muscle.

The primary cause of Duchenne muscular dystrophy (DMD) is a mutation in the dystrophin gene, leading to absence of the corresponding protein, disruption of the dystrophin-associated protein complex, and substantial changes in skeletal muscle pathology. Although the primary defect is known and the histological pathology well documented, the underlying molecular pathways remain in question. To clarify these pathways, we used expression microarrays to compare individual gene expression profiles for skeletal muscle biopsies from DMD patients and unaffected controls. We have previously published expression data for the 12,500 known genes and full-length expressed sequence tags (ESTs) on the Affymetrix HG-U95Av2 chips. Here we present comparative expression analysis of the 50,000 EST clusters represented on the remainder of the Affymetrix HG-U95 set. Individual expression profiles were generated for biopsies from 10 DMD patients and 10 unaffected control patients. Two methods of statistical analysis were used to interpret the resulting data (t-test analysis to determine the statistical significance of differential expression and geometric fold change analysis to determine the extent of differential expression). These analyses identified 183 probe sets (59 of which represent known genes) that differ significantly in expression level between unaffected and disease muscle. This study adds to our knowledge of the molecular pathways that are altered in the dystrophic state. In particular, it suggests that signaling pathways might be substantially involved in the disease process. It also highlights a large number of unknown genes whose expression is altered and whose identity therefore becomes important in understanding the pathogenesis of muscular dystrophy.

Biopsy↗
PubMed2006

Analysis of gene expression differences between utrophin/dystrophin-deficient vs mdx skeletal muscles reveals a specific upregulation of slow muscle genes in limb muscles.

Dystrophin deficiency leads to the progressive muscle wasting disease Duchenne muscular dystrophy (DMD). Dystrophin-deficient mdx mice are characterized by skeletal muscle weakness and degeneration but they appear outwardly normal in contrast to DMD patients. Mice lacking both dystrophin and the dystrophin homolog utrophin [double knockout (dko)] have muscle degeneration similar to mdx mice, but they display clinical features similar to DMD patients. Dko limb muscles also lack postsynaptic membrane folding and display fiber-type abnormalities including an abundance of phenotypically oxidative muscle fibers. Extraocular muscles, which are spared in mdx mice, show a significant pathology in dko mice. In this study, microarray analysis was used to characterize gene expression differences between mdx and dko tibialis anterior and extraocular skeletal muscles in an effort to understand the phenotypic differences between these two dystrophic mouse models. Analysis of gene expression differences showed that upregulation of slow muscle genes specifically characterizes dko limb muscle and suggests that upregulation of these genes may directly account for the more severe phenotype of dko mice. To investigate whether any upregulation of slow genes is retained in vitro, independent of postsynaptic membrane abnormalities, we derived mdx and dko primary myogenic cultures and analyzed the expression of Myh7 and Myl2. Real-time reverse transcriptase-polymerase chain reaction analysis demonstrates that transcription of these slow genes is also upregulated in dko vs mdx myotubes. This data suggests that at least part of the fiber-type abnormality is due directly to the combined absence of utrophin and dystrophin and is not an indirect effect of the postsynaptic membrane abnormalities.

Animals↗
PubMed2006

Therapeutic restoration of dystrophin expression in Duchenne muscular dystrophy.

It is 20 years since the discovery of the genetic defect causing Duchenne muscular dystrophy (DMD). This X-linked progressive and fatal myopathy is due to the absence of a functional version of a critical sub-sarcolemmal protein called dystrophin that appears to act both as a structural and as a signalling molecule in the muscle fibre. A number of molecular approaches have been developed to restore the expression of dystrophin in DMD patients. Pre-clinical experiments have demonstrated the potential of delivery of recombinant versions of the DMD gene using viral or non-viral vectors and importantly several of these systems are compatible with vascular delivery, an essential feature as all muscles are affected in this condition. Other studies have shown that antisense oligonucleotides can modify the splicing of the primary transcript to provide an internally truncated but still functional protein. Alternatively, in approximately 10-20% of cases it is possible to chemically persuade the translational machinery to read-through a pre-mature stop codon. The pre-clinical results of the last 4 years have encouraged the development of clinical trials for all of the above.

Animals↗
PubMed2001

Progress in gene therapy for Duchenne muscular dystrophy.

Gene transfer research for Duchenne muscular dystrophy (DMD) has brought the goal of successful treatment of this devastating, inherited disease closer to being a reality. Although gene therapeutic approaches for DMD patients are not yet in clinical use, recent advances using DMD animal models are encouraging. Progress in vector design, such as high-capacity adenoviral vectors, targeted adenoviral vectors, and heterodimerization of DNA delivered by adeno-associated virus (AAV) vectors have advanced the field considerably. The recent studies into the pharmacologic-induced read-through of stop codons, the increased study of utrophin and its upregulation, and the introduction of point mutation correction using chimeric oligonucleotides have expanded the field, providing new avenues of inquiry.

Anti-Bacterial Agents↗
PubMed1987

Abnormal protein metabolism in skin fibroblasts in vitro from patients with Duchenne muscular dystrophy.

Rates of protein turnover have been measured on a statistical basis in Duchenne muscular dystrophy and normal skin fibroblasts populations in vitro. At comparable numbers of cumulative population doublings, protein synthesis was significantly reduced by about 24% in DMD fibroblasts as compared to normal fibroblasts (p less than 0.01, N = 12). Degradation of short lived proteins was significantly enhanced by about 60% (p less than 0.05, N = 18), and the degradation of long lived proteins was significantly increased by about 28% (p less than 0.05, N = 18) in DMD fibroblast populations in vitro. The enhanced degradation of long lived proteins in DMD fibroblasts can be reduced to basal levels of degradation by the use of the protease inhibitors leupeptin and Ep475 (p less than 0.05, N = 9).

Adolescent↗
PubMed1992

Comparative metabolism of clinically important precursors of N-desmethyldiazepam using phenobarbitone-pretreated rat liver microsomes.

Phenobarbitone-pretreated male Sprague-Dawley rat liver microsomes were used to examine C3-hydroxylation and N-dealkylation of four clinically important benzodiazepines: diazepam (DZP), prazepam (PZP), pinazepam (PIN) and halazepam (HZP). These substrates differ only in the nature of the N-substituent of the B ring and N-desmethyldiazepam (DMD) is the N-dealkylation product in each case. C3-Hydroxylation was accordingly also studied with DMD as substrate. All monooxygenations were studied with substrates at a concentration of 10 microM, in the absence of solubilizing agents, and under conditions where the production of secondary metabolites was minimized. A 20-fold variation in the rate of C3-hydroxylation was recorded across the five substrates with HZP showing the highest rate and DMD showing the lowest rate. An almost equally large range of variation was shown for the N-dealkylation reaction, with PZP undergoing this biotransformation more than 17 times faster than DZP. Log P values (a measure of lipophilicity) for the five substrates were determined using an HPLC method and a remarkable lack of correspondence between this substrate parameter and either of the monooxygenations was noted. This suggests that multiple substrate determinants govern the relative rates of these monooxygenations. It was, however, notable that the additive rate of metabolism of these substrates by both monooxygenase routes did show an excellent correlation with substrate lipophilicity.

Animals↗
PubMed1980

Erythrocyte acetylcholinesterase in Duchenne muscular dystrophy.

The activity and the activation energy (25--43 degrees C) of acetylcholinesterase did not differ between erythrocytes from patients with Duchenne muscular dystrophy (DMD) and controls. The Hill coefficient for the inhibition of the enzyme activity by fluoride was 1 in both groups. The dose of fluoride for 50% inhibition of the enzyme activity differed between samples prepared in different ways, but not between DMD and controls. The present results suggest that there is no gross abnormality in erythrocyte acetylcholinesterase or its environment in the erythrocyte membrane in DMD.

Acetylcholinesterase↗
PubMed1981

Creatine kinase isoenzymes in cultured human muscle cells. II. A study of carrier females for Duchenne muscular dystrophy by needle and open biopsy.

Creatine kinase (CK) isoenzymes, total and specific CK activities and protein concentrations were measured in the cultured cells from muscle biopsies of 18 carriers of Duchenne muscular dystrophy (DMD) and the results compared with those in the cultures of patients with DMD and other neuromuscular disorders. The proportion of MB and BB isoenzyme in the carriers was similar to that in boys with DMD and in patients with other myogenic disorders, and significantly different from neurogenic patients. CK isoenzyme analysis appears to be a more sensitive index of in vitro differentiation than estimation of CK activities. Cell differentiation is reduced and the incidence of cell death increased in cultures derived from needle rather than open biopsies.

Biopsy↗
PubMed1984

A spin label study of the erythrocyte membrane in mothers and sisters of patients suffering from Duchenne muscular dystrophy.

The erythrocyte membranes of mothers and sisters of boys suffering from Duchenne Muscular Dystrophy (DMD) have been studied by spin labelling. Two oxazolidine nitroxide derivatives of stearic acid were used. With the first of them (16 NS) which probes the hydrophobic part of the phospholipids, we measured the fluidity of the membrane as a function of temperature. The second nitroxide derivative (5 NS) probes the membrane near the phospholipid polar heads. The amplitude of the electron spin resonance signal was studied as a function of the spectrometer microwave power in order to determine the paramagnetic label saturation behaviour. No significant difference was observed between the control adult women and the carrier mothers. On the contrary, almost all the normal young premenarchial girls showed simultaneously a break in the fluidity vs. temperature plot of the 16 NS probe and a saturation phenomenon of the 5 NS label signal. In about 50% of the DMD boys' sisters, no break in the temperature plot nor saturation behaviour was observed. This corresponds to the theoretical repartition between normal and carrier girls if one admits that about 30% of the latter do not have any detectable membrane abnormality, as in the case of the creatine kinase (CK) test which shows about 30% of normal levels in carrier women. The study of the erythrocyte membrane in young girls can then be an useful complementary tool to detect DMD carriers.

Adolescent↗
PubMed1984

Calcium-activated neutral protease from muscle and platelets of Duchenne muscular dystrophy cases.

Calcium-activated neutral protease (CANP) has been purified from its endogenous inhibitor and its activity is monitored in the muscle of Duchenne Muscular Dystrophy (DMD) patients. The specific activity of the enzyme is found to be significantly higher as compared to normal. CANP from platelets of DMD patients is significantly higher as compared to activities in other myopathies and controls. Platelet CANP, therefore, may prove to be an index of pathological condition in DMD, since other myopathies do not show such a significant change.

Adolescent↗