31 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

    Outcome of empirical or targeted antifungal therapy after antifungal prophylaxis in febrile neutropenia

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    Azole prophylaxis has been shown to be effective in preventing invasive fungal infections (IFIs) and increasing survival in patients with prolonged neutropenia after myelosuppressive chemotherapy for haematological malignancies. Similarly, empirical antifungal therapy for persistent neutropenic fever has been shown to reduce IFI-related mortality. However, to date, there is little information with regard to the outcome of patients who receive both strategies. Here, we present our retrospective data on three cohorts of patients receiving empirical or targeted antifungal therapy after different antifungal prophylaxis regimens. All records from patients who received myelosuppressive induction chemotherapy for acute myelogenous leukemia (AML) in our centre from 2004-2010 were analysed. From 2004-2006, itraconazole was used as antifungal prophylaxis; for the first 6 months in 2007, local polyenes and from mid-2007 till 2010, posaconazole. Data of 315 courses of chemotherapy in 211 patients were analysed. Antifungal therapy (empirical or targeted, time point and antifungal agent at the physician's discretion) was initiated in 50/174 (29 %), 7/18 (39 %) and 34/123 courses (28 %, p = 0.615) in the itra cohort, the cohort without systemic prophylaxis and the posa cohort, respectively, and was effective in 24/50 (48 %), 5/7 (71 %) and 22/34 courses (65 %, p = 0.221), respectively. IFI occurred in 25/174 (14 %), 4/18 (22 %) and 16/123 (13 %) courses, respectively (p = 0.580). IFI-related survival was not different in the three cohorts. Antifungal treatment in patients with AML who received azole prophylaxis resulted in the expected efficacy-importantly, prior posaconazole prophylaxis did not render subsequent antifungal treatment less effective than prior itraconazole prophylaxis

    Insuficiência renal aguda em paciente tratada com ATRA e anfotericina B: relato de caso

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    O presente relato apresenta o caso clínico de uma paciente com leucemia promie-locítica aguda tratada com ácido todo-transretinoico (ATRA), que apresentou suspeita de síndrome do ácido transreti-noico (síndrome de ATRA). Com a ocor-rência de leucopenia febril inespecífica, foram associados ao tratamento antimi-crobianos e antifúngicos. A diminuição da função renal, observada inicialmente, contribuiu para a suspeita de síndrome de ATRA, que foi agravada pelos antifúngi-cos. Assim, o uso de ATRA foi suspenso, mas somente 8 dias depois foi caracteriza-da pneumonia e descartada a hipótese de síndrome de ATRA. Nesse contexto, foi discutida a nefrotoxicidade do ATRA e a potencialização desse efeito adverso pelo uso de antifúngicos nefrotóxicos, em par-ticular da anfotericina B, assim como a im-portância do diagnóstico diferencial entre síndrome de ATRA e doença infecciosa
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