Thomas Sejersen

cDNA cloning and chromosomal localization of human alpha(11) integrin. A collagen-binding, I domain-containing, beta(1)-associated integrin alpha-chain present in muscle tissues.

We previously identified a novel integrin α-chain in human fetal muscle cells (Gullberg, D., Velling, T., Sjöberg, G., and Sejersen, T. (1995) Dev. Dyn. 204, 57–65). We have now isolated the full-length cDNA for this integrin subunit, α11. The open reading frame of the cDNA encodes a precursor of 1188 amino acids. The predicted mature protein of 1166 amino acids contains seven conserved FG-GAP repeats, an I domain with a metal ion-dependent adhesion site motif, a short transmembrane region, and a unique cytoplasmic domain of 24 amino acids containing the sequence GFFRS. α11, like other I domain integrins, lacks a dibasic cleavage site for generation of a heavy chain and a light chain, and it contains three potential divalent cation binding sites in repeats 5–7. The presence of 22 inserted amino acids in the extracellular stalk portion (amino acids 804–826) distinguishes the α11 integrin sequence from other integrin α-chains. Amino acid sequence comparisons reveal the highest identity of 42% with the α10 integrin chain. Immunoprecipitation with antibodies to α11 integrin captures a 145-kDa protein distinctly larger than the 140-kDa α2 integrin chain when analyzed by SDS-polyacrylamide gel electrophoresis under nonreducing conditions. Fluorescence in situ hybridization maps the integrin α11 gene to chromosome 15q23, in the vicinity of an identified locus for Bardet-Biedl syndrome. Based on Northern blotting, integrin α11 mRNA levels are high in the adult human uterus and in the heart and intermediate in skeletal muscle and some other tissues tested. During in vitro myogenic differentiation, α11 mRNA and protein are up-regulated. Studies of ligand binding properties show that α11β1binds collagen type I-Sepharose, and cultured muscle cells localize α11β1 into focal contacts on collagen type I. Future studies will reveal the importance of α11β1 for muscle development and integrity in adult muscle and other tissues.

Consensus statement on standard of care for congenital muscular dystrophies

Congenital muscular dystrophies are a group of rare neuromuscular disorders with a wide spectrum of clinical phenotypes. Recent advances in understanding the molecular pathogenesis of congenital muscular dystrophy have enabled better diagnosis. However, medical care for patients with congenital muscular dystrophy remains very diverse. Advances in many areas of medical technology have not been adopted in clinical practice. The International Standard of Care Committee for Congenital Muscular Dystrophy was established to identify current care issues, review literature for evidence-based practice, and achieve consensus on care recommendations in 7 areas: diagnosis, neurology, pulmonology, orthopedics/rehabilitation, gastroenterology/ nutrition/speech/oral care, cardiology, and palliative care. To achieve consensus on the care recommendations, 2 separate online surveys were conducted to poll opinions from experts in the field and from congenital muscular dystrophy families. The final consensus was achieved in a 3-day workshop conducted in Brussels, Belgium, in November 2009. This consensus statement describes the care recommendations from this committee.

Beneficial effect from a cognitive training programme on children with acquired brain injuries demonstrated in a controlled study

Primary objective: To test the effectiveness of a cognitive training programme in children and adolescents with attention and memory deficits after acquired brain injury (ABI). Research design: Randomized controlled study. Participants: Thirty-eight children with ABI, 9–16 years of age. Methods and procedures: The treatment group trained with the cognitive programme for 30 minutes per day interactively with a teacher or parent for a period of 17 weeks. Children in the control group had a freely chosen interactive activity 30 minutes daily for 17 weeks. Pre- and post-training assessments were made using a neuropsychological test battery. Main outcome and results: Significant improvements in the majority of neuropsychological tests of sustained and selective attention as well as in memory performance were shown in the treatment group as compared to controls. Conclusions: The immediate effect of the training programme improved complex attention and memory functions, indicating that this method may be a valuable treatment option for improving cognitive efficiency in children after ABI. On the basis of these results, the next step will be to evaluate long-term effects and further ecological validity.

Consensus statement on standard of care for congenital myopathies.

Recent progress in scientific research has facilitated accurate genetic and neuropathological diagnosis of congenital myopathies. However, given their relatively low incidence, congenital myopathies remain unfamiliar to the majority of care providers, and the levels of patient care are extremely variable. This consensus statement aims to provide care guidelines for congenital myopathies. The International Standard of Care Committee for Congenital Myopathies worked through frequent e-mail correspondences, periodic conference calls, 2 rounds of online surveys, and a 3-day workshop to achieve a consensus for diagnostic and clinical care recommendations. The committee includes 59 members from 10 medical disciplines. They are organized into 5 working groups: genetics/diagnosis, neurology, pulmonology, gastroenterology/nutrition/speech/oral care, and orthopedics/rehabilitation. In each care area the authors summarize the committee’s recommendations for symptom assessments and therapeutic interventions. It is the committee’s goal that through these recommendations, patients with congenital myopathies will receive optimal care and improve their disease outcome.

Best Practice Guidelines on molecular diagnostics in Duchenne/Becker muscular dystrophies

DNA Laboratory, GSTS Pathology, Guy’s Hospital, London SE1 9RT, UK Universite Montpellier1, UFR Medecine and INSERM U827, Montpellier F-34000, France Department of Human and Clinical Genetics, LUMC, 2333 AL Leiden, The Netherlands d Sezione di Genetica Medica, Dipartimento di Medicina Sperimentale e Diagnostica Universita di Ferrara, Italy Karolinska Institute, Neuropediatric Unit, Stockholm 17176, Sweden Universitat Wurzburg, Institut fur Humangenetik, Biozentrum, 97074 Wuerzburg, Germany

Long‐term follow‐up of children with obstetric brachial plexus palsy I: functional aspects

The aims of this study were to describe the development of sequelae in obstetric brachial plexus palsy (OBPP) and to identify possible differences in functional outcome from 5 years of age to follow‐up, 2 to 15 years later. A cohort of 70 participants (35 males, 35 females; age range 7‐20y, mean 13y 6mo [SD 4y 3mo], median 13y) with OBPP of varying degrees of severity were monitored. Differences in status between 5 years of age and follow‐up were studied. Active joint motion in the shoulder and hand function, especially grip strength, generally remained unchanged or improved, whereas a slight but significant deterioration occurred in elbow function. Shoulder surgery resulted in considerable improvement of shoulder function. Participants with nerve reconstruction had a similar profile of change as the non‐operated group. It was concluded that ongoing follow‐up of children with OBPP, beyond the preschool years, is required due to decreases in elbow function, a commonly occurring restriction in external rotation of the shoulder, together with individual variations in long‐term outcomes. In a related article (part II: neurophysiological aspects) long‐term neurophysiological and sensory aspects of OBPP are reported.

Pediatric Rhabdomyosarcomas Express the Intermediate Filament Nestin

Previous findings that the intermediate filament nestin is expressed in immature skeletal muscle cells prompted us to compare the staining patterns of nestin and desmin in rhabdomyosarcomas (RMSs) and in other small cell tumors of infancy. We found that nestin immunoreactivity was present in all of 29 examined typical RMSs, which also expressed desmin. Two undifferentiated tumors, primarily suspected to be RMSs, expressed nestin, but not desmin. One of these nestin-positive, desmin-negative tumors was positive for the expression of the myogenic regulatory gene MyoD and is considered to represent an undifferentiated RMS. The other, a paratesticular tumor, did not contain transcripts for MyoD, and most likely does not represent a RMS. In several RMSs and nonmuscle tumors, a z-disc-associated nestin immunoreactivity occurred as a paramalignant phenomenon in cross-striated muscle fibers adjacent to the tumor cells. Our findings indicate that nestin, although present also in tumors of the central and peripheral nervous systems, as well as in endothelial cells and in some muscle cells adjacent to tumors, is a useful complementary marker for RMS, particularly in very undifferentiated desmin-negative tumors.

Expression of PDGF α- and β-receptors in Rat Arterial Smooth Muscle Cells is Phenotype and Growth State Dependent

Adult rat arterial smooth muscle cells were shown to express mRNA for the platelet-derived growth factor (PDGF) alpha- and beta-receptors and to bind radioiodinated PDGF-AA and PDGF-BB in a phenotype-dependent and growth state-dependent manner. PDGF alpha-receptor mRNA was not detected in the intact aortic media, but appeared as the cells converted from a contractile to a synthetic phenotype during serum-free primary culture. PDGF beta-receptor mRNA was expressed already in vivo, and increased further as the cells were isolated and cultured in vitro. Exposure of the cells to human platelet PDGF resulted in increased PDGF alpha-receptor mRNA levels, decreased PDGF beta-receptor mRNA levels, and decreased binding of both PDGF-AA and PDGF-BB. Following removal of the exogenous mitogen, the content of PDGF alpha- and beta-receptor mRNA increased, as did the binding of PDGF-AA and PDGF-BB. Subsequently, the content of PDGF A-chain mRNA started to rise, and the cells retained a high rate of DNA synthesis in a serum-free medium. As a result of this autocrine stimulation, the PDGF receptors were down-regulated. Although smooth muscle cells in serum-free primary cultures bound the different PDGF isoforms to a varying extent (AA less than AB less than BB), the replicative response was of a similar magnitude. Subcultured cells bound the different PDGF isoforms in similar proportions as the primary cells. Contrary to the situation in primary cells, there was a direct correlation between the binding level and the DNA synthetic response. Moreover, the subcultured cells did not replicate in a serum-free medium. These observations support the idea that the phenotypic modulation of arterial smooth muscle cells in primary culture prepares the cells to activate autocrine growth mechanisms. When stimulated with an exogenous mitogen, they enter the cell cycle and are thereafter able to stimulate their own growth in an autocrine manner by production of PDGF-AA or a closely related molecule.

Ataluren in patients with nonsense mutation Duchenne muscular dystrophy (ACT DMD): a multicentre, randomised, double-blind, placebo-controlled, phase 3 trial

BACKGROUND Duchenne muscular dystrophy (DMD) is a severe, progressive, and rare neuromuscular, X-linked recessive disease. Dystrophin deficiency is the underlying cause of disease; therefore, mutation-specific therapies aimed at restoring dystrophin protein production are being explored. We aimed to assess the efficacy and safety of ataluren in ambulatory boys with nonsense mutation DMD. METHODS We did this multicentre, randomised, double-blind, placebo-controlled, phase 3 trial at 54 sites in 18 countries located in North America, Europe, the Asia-Pacific region, and Latin America. Boys aged 7-16 years with nonsense mutation DMD and a baseline 6-minute walk distance (6MWD) of 150 m or more and 80% or less of the predicted normal value for age and height were randomly assigned (1:1), via permuted block randomisation (block size of four) using an interactive voice-response or web-response system, to receive ataluren orally three times daily (40 mg/kg per day) or matching placebo. Randomisation was stratified by age (<9 years vs ≥9 years), duration of previous corticosteroid use (6 months to <12 months vs ≥12 months), and baseline 6MWD (<350 m vs ≥350 m). Patients, parents and caregivers, investigational site personnel, PTC Therapeutics employees, and all other study personnel were masked to group allocation until after database lock. The primary endpoint was change in 6MWD from baseline to week 48. We additionally did a prespecified subgroup analysis of the primary endpoint, based on baseline 6MWD, which is reflective of anticipated rates of disease progression over 1 year. The primary analysis was by intention to treat. This study is registered with ClinicalTrials.gov, number NCT01826487. FINDINGS Between March 26, 2013, and Aug 26, 2014, we randomly assigned 230 patients to receive ataluren (n=115) or placebo (n=115); 228 patients comprised the intention-to-treat population. The least-squares mean change in 6MWD from baseline to week 48 was -47·7 m (SE 9·3) for ataluren-treated patients and -60·7 m (9·3) for placebo-treated patients (difference 13·0 m [SE 10·4], 95% CI -7·4 to 33·4; p=0·213). The least-squares mean change for ataluren versus placebo in the prespecified subgroups was -7·7 m (SE 24·1, 95% CI -54·9 to 39·5; p=0·749) in the group with a 6MWD of less than 300 m, 42·9 m (15·9, 11·8-74·0; p=0·007) in the group with a 6MWD of 300 m or more to less than 400 m, and -9·5 m (17·2, -43·2 to 24·2; p=0·580) in the group with a 6MWD of 400 m or more. Ataluren was generally well tolerated and most treatment-emergent adverse events were mild to moderate in severity. Eight (3%) patients (n=4 per group) reported serious adverse events; all except one event in the placebo group (abnormal hepatic function deemed possibly related to treatment) were deemed unrelated to treatment. INTERPRETATION Change in 6MWD did not differ significantly between patients in the ataluren group and those in the placebo group, neither in the intention-to-treat population nor in the prespecified subgroups with a baseline 6MWD of less than 300 m or 400 m or more. However, we recorded a significant effect of ataluren in the prespecified subgroup of patients with a baseline 6MWD of 300 m or more to less than 400 m. Baseline 6MWD values within this range were associated with a more predictable rate of decline over 1 year; this finding has implications for the design of future DMD trials with the 6-minute walk test as the endpoint. FUNDING PTC Therapeutics.

Attention and memory training in children with acquired brain injuries.

Aim: To test the feasibility of the Amsterdam memory and attention training for children (Amat‐c) in Swedish children with acquired brain damage. Methods: Amat‐c consists of structured exercises in specific attention and memory techniques. Three Swedish children aged 9–16 y with acquired brain injuries and related memory and attention deficits trained with the Amat‐c method for half an hour a day in school or at home interactively with a teacher or parent for a period of 20 wk. Results: All children and their coaches completed the training without interruption. The results showed an improvement in several neuropsychological tests of sustained and selective attention as well as in memory performance. Questionnaires filled in by parents and teachers indicate that, using the Amat‐c method, the children learned strategies that improved their school achievement and self‐image.