12 research outputs found

    The HERMES Back Drift Chambers

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    The tracking system of the HERMES spectrometer behind the bending magnet consists of two pairs of large planar 6-plane drift chambers. The design and performance of these chambers is described. This description comprises details on the mechanical and electronical design, information about the gas mixture used and its properties, results on alignment, calibration, resolution, and efficiencies, and a discussion of the experience gained through the first three years of operation.Comment: 21 pages, LaTex, 16 figures include

    Search for the exotic Ξ(1860)\Xi^{--}(1860) Resonance in 340GeV/c Σ\Sigma^--Nucleus Interactions

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    We report on a high statistics search for the Ξ(1860)\Xi^{--}(1860) resonance in Σ\Sigma^--nucleus collisions at 340GeV/c. No evidence for this resonance is found in our data sample which contains 676000 Ξ\Xi^- candidates above background. For the decay channel Ξ(1860)Ξπ\Xi^{--}(1860) \to \Xi^-\pi^- and the kinematic range 0.15<xF<<x_F<0.9 we find a 3σ\sigma upper limit for the production cross section of 3.1 and 3.5 μ\mub per nucleon for reactions with carbon and copper, respectively.Comment: 5 pages, 4 figures, modification of ref. 43 and 4

    X-linked sideroblastic anaemia due to ALAS(2) mutations in the Netherlands: a disease in disguise

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    Item does not contain fulltextBACKGROUND: X-linked sideroblastic anaemia (XLSA; OMIM#300751) is the most common inherited form of sideroblastic anaemia and is associated with several mutations in the erythroid specific 5-aminolevulinate synthase gene (ALAS(2)). This gene encodes for aminolevulinic acid synthase 2 (ALAS(2)), the catalytic enzyme involved in the first en rate-limiting step of haem biosynthesis.1-3 The disorder is characterised by mostly mild hypochromic microcytic anaemia with bone marrow ring sideroblasts. Even untransfused patients with mild or no anaemia are at risk for severe systemic iron overload due to ineffective erythropoiesis. To date, 61 different ALAS(2) mutations have been reported in 120 families with XLSA. Descriptions of molecularly confirmed case series from the Netherlands, however, are lacking. METHODS: We reviewed age of presentation, clinical and biochemical features, ALAS(-)(2) defects and treatment characteristics of 15 Dutch patients from 11 unrelated families diagnosed with XLSA. RESULTS AND CONCLUSIONS: In one family a novel pathogenic c.1412G>A (p.Cys471Tyr) mutation was found. All other families shared the previously described c.1355G>A (p.Arg452His) mutation. Haplotype analysis in seven probands with the p.Arg452His mutation strongly suggests that six of them were ancestrally related. Nevertheless, their phenotype was very different. Our patients illustrate the phenotypical heterogeneity in the presentation of XLSA patients, the effectiveness of treatment regimens and the various pitfalls associated with the diagnosis, follow-up and treatment of the disease. A timely diagnosis avoids unnecessary investigations and allows adequate treatment that can prevent systemic iron load with subsequent severe life-threatening complications. Therefore, we suggest considering XLSA in both male and female patients with unexplained iron overload and/or (mild) microcytic anaemia, also at older age

    Beweegtool Foxfit voor kinderen met astma

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    Om kinderen met astma meer te laten bewegen, is de digitale tool Foxfit ontwikkeld. De tool bevat interactieve modulen met persoonlijke doelstellingen, educatie, agendavoering en een visuele terugkoppeling van het beweeggedrag

    Sportas: vitaal en zichtbaar: naar een gezonde leefstijl in een stimulerende omgeving

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    Practice guidelines for the diagnosis and management of microcytic anemias due to genetic disorders of iron metabolism or heme synthesis

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    Contains fulltext : 136560.pdf (publisher's version ) (Closed access)During recent years, our understanding of the pathogenesis of inherited microcytic anemias has gained from the identification of several genes and proteins involved in systemic and cellular iron metabolism and heme syntheses. Numerous case reports illustrate that the implementation of these novel molecular discoveries in clinical practice has increased our understanding of the presentation, diagnosis, and management of these diseases. Integration of these insights into daily clinical practice will reduce delays in establishing a proper diagnosis, invasive and/or costly diagnostic tests, and unnecessary or even detrimental treatments. To assist the clinician, we developed evidence-based multidisciplinary guidelines on the management of rare microcytic anemias due to genetic disorders of iron metabolism and heme synthesis. These genetic disorders may present at all ages, and therefore these guidelines are relevant for pediatricians as well as clinicians who treat adults. This article summarizes these clinical practice guidelines and includes background on pathogenesis, conclusions, and recommendations and a diagnostic flowchart to facilitate using these guidelines in the clinical setting

    Iron refractory iron deficiency anemia: a heterogeneous disease that is not always iron refractory

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    TMPRSS6 variants that affect protein function result in impaired matriptase-2 function and consequently uninhibited hepcidin production, leading to iron refractory iron deficiency anemia (IRIDA). This disease is characterized by microcytic, hypochromic anemia and serum hepcidin values that are inappropriately high for body iron levels. Much is still unknown about its pathophysiology, genotype-phenotype correlation, and optimal clinical management. We describe 14 different TMPRSS6 variants, of which 9 are novel, in 21 phenotypically affected IRIDA patients from 20 families living in the Netherlands; 16 out of 21 patients were female. In 7 out of 21 cases DNA sequencing and multiplex ligation dependent probe amplification demonstrated only heterozygous TMPRSS6 variants. The age at presentation, disease severity, and response to iron supplementation were highly variable, even for patients and relatives with similar TMPRSS6 genotypes. Mono-allelic IRIDA patients had a milder phenotype with respect to hemoglobin and MCV and presented significantly later in life with anemia than bi-allelic patients. Transferrin saturation (TSAT)/hepcidin ratios were lower in IRIDA probands than in healthy relatives. Most patients required parenteral iron. Genotype alone was not predictive for the response to oral iron. We conclude that IRIDA is a genotypically and phenotypically heterogeneous disease. The high proportion of female patients and the discrepancy between phenotypes of probands and relatives with the same genotype, suggest a complex interplay between genetic and acquired factors in the pathogenesis of IRIDA. In the absence of inflammation, the TSAT/hepcidin ratio is a promising diagnostic tool, even after iron supplementation has been given. Am. J. Hematol. 91:E482-E490, 2016. (c) 2016 Wiley Periodicals, Inc
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