297 research outputs found

    MAARS: a novel high-content acquisition software for the analysis of mitotic defects in fission yeast

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    Faithful segregation of chromosomes during cell division relies on multiple processes such as chromosome attachment and correct spindle positioning. Yet mitotic progression is defined by multiple parameters, which need to be quantitatively evaluated. To study the spatiotemporal control of mitotic progression, we developed a high-content analysis (HCA) approach that combines automated fluorescence microscopy with real-time quantitative image analysis and allows the unbiased acquisition of multiparametric data at the single-cell level for hundreds of cells simultaneously. The Mitotic Analysis and Recording System (MAARS) provides automatic and quantitative single-cell analysis of mitotic progression on an open-source platform. It can be used to analyze specific characteristics such as cell shape, cell size, metaphase/anaphase delays, and mitotic abnormalities including spindle mispositioning, spindle elongation defects, and chromosome segregation defects. Using this HCA approach, we were able to visualize rare and unexpected events of error correction during anaphase in wild-type or mutant cells. Our study illustrates that such an expert system of mitotic progression is able to highlight the complexity of the mechanisms required to prevent chromosome loss during cell division

    Treatment of Low-flow Vascular Malformations by Ultrasound-guided Sclerotherapy with Polidocanol Foam: 24 Cases and Literature Review

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    AbstractObjectivesTreatment by sclerotherapy has been suggested as a first-line treatment of low-flow vascular malformations. This study reports our experience in treating low-flow vascular malformations by ultrasound-guided sclerosis with polidocanol foam at the Vascular Medicine Department in Grenoble, France.DesignRetrospective single-centre consecutive series.Materials and methodsBetween January 2006 and December 2009, we analysed the complete records of patients with symptomatic low-flow vascular malformations of venous, lymphatic or complex type (Klippel–Trenaunay syndrome, KTS) treated by ultrasound-guided sclerosis. The therapeutic indication was always validated by the Consultative Committee for vascular malformations of the University Hospital of Grenoble. All vascular malformations were classified according to the Hamburg Classification. The sclerosing agent was polidocanol used as foam.ResultsA total of 24 patients between 7 and 78 years were treated (19 venous malformations, three KTSs and two venous-lymphatic malformations). The concentrations of polidocanol used ranged from 0.25% to 3%. The average number of sessions was 2.3 (1–16). After a median follow-up at 5 months after the last session, 23 out of 24 patients reported a decrease in pain; in nine cases (37.5%), over 50% reduction in size was observed, and in 14 cases (58.3%), a reduction of less than 50% of the original size was obtained. Two minor side effects were reported.ConclusionsTreatment by ultrasound-guided sclerosis using polidocanol foam seems to be well tolerated and can improve the symptoms of low-flow malformations without the risks of more aggressive sclerosing agents, such as ethanol

    Platelet FcγRIIA-induced serotonin release exacerbates the severity of Transfusion-Related Acute Lung Injury in mice

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    Transfusion-related acute lung injury (TRALI) remains a major cause of transfusion-related fatalities. The mechanism of human antibody-mediated TRALI, especially the involvement of the Fcγ receptors, is not clearly established. Contrary to mice, human platelets are unique in their expression of the FcγRIIA/CD32A receptor, suggesting that our understanding of the pathogenesis of antibody-mediated TRALI is partial, as the current murine models incompletely recapitulate the human immunology. We evaluated the role of FcγRIIA/CD32A in TRALI using a humanized mouse model expressing the FcγRIIA/CD32A receptor. When challenged with a recombinant chimeric human immunoglobulin G1/mouse anti–major histocompatibility complex class I monoclonal antibody, these mice exhibited exacerbated alveolar edema and higher mortality compared with wild-type (WT) mice. Unlike in WT mice, monocytes/macrophages in CD32A(+) mice were accessory for TRALI initiation, indicating the decisive contribution of another cell type. Platelet activation was dramatically increased in CD32A(+) animals, resulting in their increased consumption and massive release of their granule contents. Platelet depletion prevented the exacerbation of TRALI in CD32A(+) mice but did not affect TRALI in WT animals. By blocking platelet serotonin uptake with fluoxetine, we showed that the severity of TRALI in CD32A(+) mice resulted from the serotonin released by the activated platelets. Furthermore, inhibition of 5-hydroxytryptamine 2A serotonin receptor with sarpogrelate, before or after the induction of TRALI, abolished the aggravation of lung edema in CD32A(+) mice. Our findings show that platelet FcγRIIA/CD32A activation exacerbates antibody-mediated TRALI and provide a rationale for designing prophylactic and therapeutic strategies targeting the serotonin pathway to attenuate TRALI in patients

    The ATP-gated P2X1 ion channel contributes to the severity of antibody-mediated Transfusion-Related Acute Lung Injury in mice

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    The biological responses that control the development of Transfusion-Related Acute Lung Injury (TRALI), a serious post-transfusion respiratory syndrome, still need to be clarified. Since extracellular nucleotides and their P2 receptors participate in inflammatory processes as well as in cellular responses to stress, we investigated the role of the ATP-gated P2X1 cation channel in antibody-mediated TRALI. The effects of NF449, a selective P2X1 receptor (P2RX1) antagonist, were analyzed in a mouse two-hit model of TRALI. Mice were primed with lipopolysaccharide (LPS) and 24 h later challenged by administrating an anti-MHC I antibody. The selective P2RX1 antagonist NF449 was administrated before the administration of LPS and/or the anti-MHC I antibody. When given before antibody administration, NF449 improved survival while maximal protection was achieved when NF449 was also administrated before the sensitization step. Under this later condition, protein contents in bronchoalveolar lavages were dramatically reduced. Cell depletion experiments indicated that monocytes/macrophages, but not neutrophils, contribute to this effect. In addition, the reduced lung periarteriolar interstitial edemas in NF449-treated mice suggested that P2RX1 from arteriolar smooth muscle cells could represent a target of NF449. Accordingly, inhibition of TRPC6, another cation channel expressed by smooth muscle cells, also reduced TRALI-associated pulmonary interstitial and alveolar edemas. These data strongly suggest that cation channels like P2RX1 or TRPC6 participate to TRALI pathological responses

    Aortic thrombus in a patient with myeloproliferative thrombocytosis, successfully treated by pharmaceutical therapy: a case report

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    <p>Abstract</p> <p>Introduction</p> <p>Thrombosis in myeloproliferative thrombocytosis occurs usually in the microvessels and medium-sized arteries and veins and only rarely in the aorta. Aortic thrombosis is usually treated with thrombectomy. Reported here is a rare case that was treated pharmacologically.</p> <p>Case presentation</p> <p>A 60-year-old Japanese woman presented with numbness of both lower extremities. Her platelet count was 1787 × 10<sup>3</sup>/μl. Through bone marrow examination, we diagnosed her condition as myelodysplastic and/or myeloproliferative disorder-unclassifiable. Abdominal ultrasonography and computed tomographic scan revealed aortic thrombosis. Her platelet count was controlled with hydroxyurea and ranimustine. Aspirin and ticlopidine improved the numbness in both lower limbs on the second day. Aortic thrombosis was not observed in a computed tomographic scan on the seventh day.</p> <p>Conclusion</p> <p>For aortic thrombosis, surgical management is usually adopted, but pharmacological management is also an option because of its immediate curative effects.</p

    Inherited dysfunctional platelet P2Y12 receptor mutations associated with bleeding disorders

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    The platelet adenosine 5'-diphosphate (ADP) receptor P2Y12 (P2Y12R) plays a critical role in platelet aggregation. The present report illustrates an update of dysfunctional platelet P2Y12R mutations diagnosed with congenital lifelong bleeding problems. Described patients with heterozygous or homozygous substitution in the P2Y12R gene and qualitative abnormalities of the platelet P2Y12R are summarized. Recently, a further dysfunctional variant of P2Y12R has been identified in two brothers who presented with a lifelong severe bleeding disorder. During in vitro aggregation studies, the patient's platelets show a markedly reduced and rapid reversible ADP-promoted aggregation. A homozygous c.561T > A substitution that changes the codon for His187 to Gln (p.His187Gln) in the P2Y12R gene has been identified. This mutation causes no change in receptor expression but decreases the affinity of the ligand for the receptor, even at high concentrations. Structure modelling studies indicated that the p.His187Gln mutation, located in the fifth transmembrane spanning domain (TM5), impairs conformational changes of the receptor. Structural integrity of the TM5 region is necessary for agonist and antagonist binding and for correct receptor function

    TRY plant trait database - enhanced coverage and open access

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    Plant traits-the morphological, anatomical, physiological, biochemical and phenological characteristics of plants-determine how plants respond to environmental factors, affect other trophic levels, and influence ecosystem properties and their benefits and detriments to people. Plant trait data thus represent the basis for a vast area of research spanning from evolutionary biology, community and functional ecology, to biodiversity conservation, ecosystem and landscape management, restoration, biogeography and earth system modelling. Since its foundation in 2007, the TRY database of plant traits has grown continuously. It now provides unprecedented data coverage under an open access data policy and is the main plant trait database used by the research community worldwide. Increasingly, the TRY database also supports new frontiers of trait-based plant research, including the identification of data gaps and the subsequent mobilization or measurement of new data. To support this development, in this article we evaluate the extent of the trait data compiled in TRY and analyse emerging patterns of data coverage and representativeness. Best species coverage is achieved for categorical traits-almost complete coverage for 'plant growth form'. However, most traits relevant for ecology and vegetation modelling are characterized by continuous intraspecific variation and trait-environmental relationships. These traits have to be measured on individual plants in their respective environment. Despite unprecedented data coverage, we observe a humbling lack of completeness and representativeness of these continuous traits in many aspects. We, therefore, conclude that reducing data gaps and biases in the TRY database remains a key challenge and requires a coordinated approach to data mobilization and trait measurements. This can only be achieved in collaboration with other initiatives

    Phosphorylated Nucleolin Interacts with Translationally Controlled Tumor Protein during Mitosis and with Oct4 during Interphase in ES Cells

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    BACKGROUND: Reprogramming of somatic cells for derivation of either embryonic stem (ES) cells, by somatic cell nuclear transfer (SCNT), or ES-like cells, by induced pluripotent stem (iPS) cell procedure, provides potential routes toward non-immunogenic cell replacement therapies. Nucleolar proteins serve as markers for activation of embryonic genes, whose expression is crucial for successful reprogramming. Although Nucleolin (Ncl) is one of the most abundant nucleolar proteins, its interaction partners in ES cells have remained unidentified. METHODOLOGY: Here we explored novel Ncl-interacting proteins using in situ proximity ligation assay (PLA), colocalization and immunoprecipitation (IP) in ES cells. PRINCIPAL FINDINGS: We found that phosphorylated Ncl (Ncl-P) interacted with translationally controlled tumor protein (Tpt1) in murine ES cells. The Ncl-P/Tpt1 complex peaked during mitosis and was reduced upon retinoic acid induced differentiation, signifying a role in cell proliferation. In addition, we showed that Ncl-P interacted with the transcription factor Oct4 during interphase in human as well as murine ES cells, indicating of a role in transcription. The Ncl-P/Oct4 complex peaked during early stages of spontaneous human ES cell differentiation and may thus be involved in the initial differentiation event(s) of mammalian development. CONCLUSIONS: Here we described two novel protein-protein interactions in ES cells, which give us further insight into the complex network of interacting proteins in pluripotent cells

    Resident Cardiac Immune Cells and Expression of the Ectonucleotidase Enzymes CD39 and CD73 after Ischemic Injury

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    BACKGROUND: The ectoenzymes CD39 and CD73 are expressed by a broad range of immune cells and promote the extracellular degradation of nucleotides to anti-inflammatory adenosine. This study explored the abundance of CD73 and CD39 on circulating and resident cardiac leukocytes and coronary endothelial cells under control conditions and in response to inflammation following myocardial ischemia and reperfusion (I/R). METHODS AND RESULTS: A method was elaborated to permit FACS analysis of non-myocardial cells (resident leukocytes, coronary endothelium and CD31(-) CD45(-) cells) of the unstressed heart. Under control conditions the murine heart contained 2.3 × 10(3) resident leukocytes/mg tissue, the most prominent fraction being antigen-presenting mononuclear cells (CD11b(+) CD11c(+) F4/80(+) MHCII(+)) followed by B-cells, monocytes and T-cells. CD73 was highly expressed on circulating and resident cardiac lymphoid cells with little expression on myeloid cells, while the opposite was true for CD39. Cardiomyocytes and erythrocytes do not measurably express CD39/CD73 and CD39 dominates on coronary endothelium. Three days after I/R, CD73 was significantly upregulated on invading granulocytes (2.8-fold) and T-cells (1.5-fold). Compared with coronary endothelial cells, CD73 associated with leukocytes comprised 2/3 of the total cardiac CD73. CONCLUSION: Our study suggests that extracellular ATP formed during I/R is preferentially degraded by CD39 present on myeloid cells, while the formation of immunosuppressive adenosine is mainly catalysed by CD73 present on granulocytes and lymphoid cells. Upregulated CD73 on granulocytes and T-cells infiltrating the injured heart is consistent with the existence of an autocrine adenosinergic loop which may promote the healing process
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