113 research outputs found

    Quick release connector Patent

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    Design and development of quick release connecto

    Bim and Mcl-1 exert key roles in regulating JAK2V617F cell survival

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    <p>Abstract</p> <p>Background</p> <p>The JAK2<sup>V617F </sup>mutation plays a major role in the pathogenesis of myeloproliferative neoplasms and is found in the vast majority of patients suffering from polycythemia vera and in roughly every second patient suffering from essential thrombocythemia or from primary myelofibrosis. The V617F mutation is thought to provide hematopoietic stem cells and myeloid progenitors with a survival and proliferation advantage. It has previously been shown that activated JAK2 promotes cell survival by upregulating the anti-apoptotic STAT5 target gene Bcl-xL. In this study, we have investigated the role of additional apoptotic players, the pro-apoptotic protein Bim as well as the anti-apoptotic protein Mcl-1.</p> <p>Methods</p> <p>Pharmacological inhibition of JAK2/STAT5 signaling in JAK2<sup>V617F </sup>mutant SET-2 and MB-02 cells was used to study effects on signaling, cell proliferation and apoptosis by Western blot analysis, WST-1 proliferation assays and flow cytometry. Cells were transfected with siRNA oligos to deplete candidate pro- and anti-apoptotic proteins. Co-immunoprecipitation assays were performed to assess the impact of JAK2 inhibition on complexes of pro- and anti-apoptotic proteins.</p> <p>Results</p> <p>Treatment of JAK2<sup>V617F </sup>mutant cell lines with a JAK2 inhibitor was found to trigger Bim activation. Furthermore, Bim depletion by RNAi suppressed JAK2 inhibitor-induced cell death. Bim activation following JAK2 inhibition led to enhanced sequestration of Mcl-1, besides Bcl-xL. Importantly, Mcl-1 depletion by RNAi was sufficient to compromise JAK2<sup>V617F </sup>mutant cell viability and sensitized the cells to JAK2 inhibition.</p> <p>Conclusions</p> <p>We conclude that Bim and Mcl-1 have key opposing roles in regulating JAK2<sup>V617F </sup>cell survival and propose that inactivation of aberrant JAK2 signaling leads to changes in Bim complexes that trigger cell death. Thus, further preclinical evaluation of combinations of JAK2 inhibitors with Bcl-2 family antagonists that also tackle Mcl-1, besides Bcl-xL, is warranted to assess the therapeutic potential for the treatment of chronic myeloproliferative neoplasms.</p

    Transatlantic combined and comparative data analysis of 1095 patients with urea cycle disorders?A successful strategy for clinical research of rare diseases

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    BACKGROUND: To improve our understanding of urea cycle disorders (UCDs) prospectively followed by two North American (NA) and European (EU) patient cohorts. AIMS: Description of the NA and EU patient samples and investigation of the prospects of combined and comparative analyses for individuals with UCDs. METHODS: Retrieval and comparison of the data from 1095 individuals (NA: 620, EU: 475) from two electronic databases. RESULTS: The proportion of females with ornithine transcarbamylase deficiency (fOTC-D), particularly those being asymptomatic (asfOTC-D), was higher in the NA than in the EU sample. Exclusion of asfOTC-D resulted in similar distributions in both samples. The mean age at first symptoms was higher in NA than in EU patients with late onset (LO), but similar for those with early (</= 28 days) onset (EO) of symptoms. Also, the mean age at diagnosis and diagnostic delay for EO and LO patients were similar in the NA and EU cohorts. In most patients (including fOTC-D), diagnosis was made after the onset of symptoms (59.9%) or by high-risk family screening (24.7%), and less often by newborn screening (8.9%) and prenatal testing (3.7%). Analysis of clinical phenotypes revealed that EO patients presented with more symptoms than LO individuals, but that numbers of symptoms correlated with plasma ammonium concentrations in EO patients only. Liver transplantation was reported for 90 NA and 25 EU patients. CONCLUSIONS: Combined analysis of databases drawn from distinct populations opens the possibility to increase sample sizes for natural history questions, while comparative analysis utilizing differences in approach to treatment can evaluate therapeutic options and enhance long-term outcome studies

    Retinoic Acid-Dependent Signaling Pathways and Lineage Events in the Developing Mouse Spinal Cord

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    Studies in avian models have demonstrated an involvement of retinoid signaling in early neural tube patterning. The roles of this signaling pathway at later stages of spinal cord development are only partly characterized. Here we use Raldh2-null mouse mutants rescued from early embryonic lethality to study the consequences of lack of endogenous retinoic acid (RA) in the differentiating spinal cord. Mid-gestation RA deficiency produces prominent structural and molecular deficiencies in dorsal regions of the spinal cord. While targets of Wnt signaling in the dorsal neuronal lineage are unaltered, reductions in Fibroblast Growth Factor (FGF) and Notch signaling are clearly observed. We further provide evidence that endogenous RA is capable of driving stem cell differentiation. Raldh2 deficiency results in a decreased number of spinal cord derived neurospheres, which exhibit a reduced differentiation potential. Raldh2-null neurospheres have a decreased number of cells expressing the neuronal marker β-III-tubulin, while the nestin-positive cell population is increased. Hence, in vivo retinoid deficiency impaired neural stem cell growth. We propose that RA has separable functions in the developing spinal cord to (i) maintain high levels of FGF and Notch signaling and (ii) drive stem cell differentiation, thus restricting both the numbers and the pluripotent character of neural stem cells

    Environmental Design for Patient Families in Intensive Care Units

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