8 research outputs found

    Multi-messenger observations of a binary neutron star merger

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    On 2017 August 17 a binary neutron star coalescence candidate (later designated GW170817) with merger time 12:41:04 UTC was observed through gravitational waves by the Advanced LIGO and Advanced Virgo detectors. The Fermi Gamma-ray Burst Monitor independently detected a gamma-ray burst (GRB 170817A) with a time delay of ~1.7 s with respect to the merger time. From the gravitational-wave signal, the source was initially localized to a sky region of 31 deg2 at a luminosity distance of 40+8-8 Mpc and with component masses consistent with neutron stars. The component masses were later measured to be in the range 0.86 to 2.26 Mo. An extensive observing campaign was launched across the electromagnetic spectrum leading to the discovery of a bright optical transient (SSS17a, now with the IAU identification of AT 2017gfo) in NGC 4993 (at ~40 Mpc) less than 11 hours after the merger by the One- Meter, Two Hemisphere (1M2H) team using the 1 m Swope Telescope. The optical transient was independently detected by multiple teams within an hour. Subsequent observations targeted the object and its environment. Early ultraviolet observations revealed a blue transient that faded within 48 hours. Optical and infrared observations showed a redward evolution over ~10 days. Following early non-detections, X-ray and radio emission were discovered at the transient’s position ~9 and ~16 days, respectively, after the merger. Both the X-ray and radio emission likely arise from a physical process that is distinct from the one that generates the UV/optical/near-infrared emission. No ultra-high-energy gamma-rays and no neutrino candidates consistent with the source were found in follow-up searches. These observations support the hypothesis that GW170817 was produced by the merger of two neutron stars in NGC4993 followed by a short gamma-ray burst (GRB 170817A) and a kilonova/macronova powered by the radioactive decay of r-process nuclei synthesized in the ejecta

    Prospective evaluation of coagulopathy in multiple myeloma patients before, during and after various chemotherapeutic regimens

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    Background: Venous thromboembolism (VTE) occurs frequently in multiple myeloma patients, especially during induction treatment with thalidomide in combination with anthracyclines and/or dexamethasone. Several coagulation abnormalities have been described in untreated myeloma patients, but these have not been prospectively evaluated during and after treatment. Patients and methods: We performed a prospective study in 138 multiple myeloma patients in whom coagulation factor levels were evaluated longitudinally before, during induction and after intensification. Patients were randomized to induction treatment consisting of adriamycin and dexamethason, in combination with either vincristin (VAD), thalidomide (TAD), or bortezomib (PAD) followed by high-dose melphalan (HDM) and autologous stem cell transplant (ASCT). Results: Factor VHLC (FVIII:C) and von Willebrand factor (VWF) were significantly elevated before treatment (median FVIII:C 2.26U/ml, VWF:Ag 1.95 U/ml). Irrespective of the type of induction regimen, these variables increased strongly during induction therapy (FVIII:C 2.55 U/ml and VWF:Ag 2.96 U/ml). Fibrinogen also showed a significant increase after induction therapy (3.5 g/l pre-treatment and 4.0 g/l after treatment, respectively, P < 0.001). This was significantly higher in TAD than VAD treated patients. Three to six month after ASCT levels of VWF and FVIII:C had decreased to values lower than observed before treatment (1.71 and 1.67 U/ml respectively). There was no correlation between the increased levels at start and the response of multiple myeloma to treatment. High levels of VWF, fibrinogen and FVIII:C before start of treatment were significantly associated with mortality. Fourteen patients (10%) developed a venous thrombotic event (VTE). The coagulation factor abnormalities before and during treatment were not associated with the development of VTE. Conclusion: During induction treatment several changes in coagulation factor levels are observed, which may result in a prothrombotic state. Larger studies are required to establish whether the changes in these coagulation factors during induction treatment contribute to the increased risk of venous thromboembolism in multiple myeloma patients. (c) 2007 Elsevier Ltd. All rights reserved

    Peripheral T-cell lymphomas unspecified presenting in the skin:analysis of prognostic factors in a group of 82 patients

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    In the present study the clinicopathologic and immunophenotypic features of 82 patients with a CD30(-) peripheral T-cell lymphoma, unspecified, presenting in the skin were evaluated. The purpose of this study was to find out whether subdivision of these lymphomas on the basis of cell size, phenotype, or presentation with only skin lesions is clinically relevant. The study group included 46 primary cutaneous CD30(-) large cell lymphomas and 17 small/medium-sized T-cell lymphomas as well as 17 peripheral T-cell lymphomas with both skin and extracutaneous disease at the time of diagnosis. Patients with primary cutaneous small- or medium-sized T-cell lymphomas had a significantly better prognosis (5-year-overall survival, 45%) than patients with primary cutaneous CD30(-) large T-cell lymphomas (12%) and patients presenting with concurrent extracutaneous disease (12%). The favorable prognosis in this group with primary cutaneous small- or medium-sized T-cell lymphomas was particularly found in patients presenting with localized skin lesions expressing a CD3(+)CD4(+)CD8(-) phenotype. In the primary cutaneous T-cell lymphoma (CTCL) group and in the concurrent group, neither extent of skin lesions nor phenotype had any effect on survival. Our results indicate that peripheral T-cell lymphomas, unspecified, presenting in the skin have an unfavorable prognosis, irrespective of the presence or absence of extracutaneous disease at the time of diagnosis, cell size, and expression of a CD4(+) or CD8(+) phenotype. The only exception was a group of primary cutaneous small- or medium-sized pleomorphic CTCLs with a CD3(+)CD4(+)CD8(-) phenotype and presenting with localized skin lesions. (C) 2003 by The American Society of Hematology
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