Unveiling Soft Gamma-Ray Repeaters with INTEGRAL

Thanks to INTEGRAL's long exposures of the Galactic Plane, the two brightest Soft Gamma-Ray Repeaters, SGR 1806-20 and SGR 1900+14, have been monitored and studied in detail for the first time at hard-X/soft gamma rays. This has produced a wealth of new scientific results, which we will review here. Since SGR 1806-20 was particularly active during the last two years, more than 300 short bursts have been observed with INTEGRAL. and their characteristics have been studied with unprecedented sensitivity in the 15-200 keV range. A hardness-intensity anticorrelation within the bursts has been discovered and the overall Number-Intensity distribution of the bursts has been determined. In addition, a particularly active state, during which ~100 bursts were emitted in ~10 minutes, has been observed on October 5 2004, indicating that the source activity was rapidly increasing. This eventually led to the Giant Flare of December 27th 2004, for which a possible soft gamma-ray (>80 keV) early afterglow has been detected. The deep observations allowed us to discover the persistent emission in hard X-rays (20-150 keV) from 1806-20 and 1900+14, the latter being in a quiescent state, and to directly compare the spectral characteristics of all Magnetars (two SGRs and three Anomalous X-ray Pulsars) detected with INTEGRAL.Comment: 8 pages, 7 figures, Presented at the conference "Isolated Neutron Stars: from the Surface to the Interior", London, UK, 24-28 April 200

The first multi-wavelength campaign of AXP 4U 0142+61 from radio to hard X-rays

For the first time a quasi-simultaneous multi-wavelength campaign has been performed on an Anomalous X-ray Pulsar from the radio to the hard X-ray band. 4U 0142+61 was an INTEGRAL target for 1 Ms in July 2005. During these observations it was also observed in the X-ray band with Swift and RXTE, in the optical and NIR with Gemini North and in the radio with the WSRT. In this paper we present the source-energy distribution. The spectral results obtained in the individual wave bands do not connect smoothly; apparently components of different origin contribute to the total spectrum. Remarkable is that the INTEGRAL hard X-ray spectrum (power-law index 0.79 +/- 0.10) is now measured up to an energy of ~230 keV with no indication of a spectral break. Extrapolation of the INTEGRAL power-law spectrum to lower energies passes orders of magnitude underneath the NIR and optical fluxes, as well as the low ~30 microJy (2 sigma) upper limit in the radio band.Comment: 6 pages, 1 figure. To be published in the proceedings of the conference "Isolated Neutron Stars: from the Interior to the Surface" (April 24-28, 2006, London, UK), eds. S. Zane, R. Turolla and D. Pag

Preventive Antibacterial Therapy in Acute Ischemic Stroke: A Randomized Controlled Trial

BACKGROUND: Pneumonia is a major risk factor of death after acute stroke. In a mouse model, preventive antibacterial therapy with moxifloxacin not only prevents the development of post-stroke infections, it also reduces mortality, and improves neurological outcome significantly. In this study we investigate whether this approach is effective in stroke patients. METHODS: Preventive ANtibacterial THERapy in acute Ischemic Stroke (PANTHERIS) is a randomized, double-blind, placebo-controlled trial in 80 patients with severe, non-lacunar, ischemic stroke (NIHSS>11) in the middle cerebral artery (MCA) territory. Patients received either intravenous moxifloxacin (400 mg daily) or placebo for 5 days starting within 36 hours after stroke onset. Primary endpoint was infection within 11 days. Secondary endpoints included neurological outcome, survival, development of stroke-induced immunodepression, and induction of bacterial resistance. FINDINGS: On intention-to treat analysis (79 patients), the infection rate at day 11 in the moxifloxacin treated group was 15.4% compared to 32.5% in the placebo treated group (p = 0.114). On per protocol analysis (n = 66), moxifloxacin significantly reduced infection rate from 41.9% to 17.1% (p = 0.032). Stroke associated infections were associated with a lower survival rate. In this study, neurological outcome and survival were not significantly influenced by treatment with moxifloxacin. Frequency of fluoroquinolone resistance in both treatment groups did not differ. On logistic regression analysis, treatment arm as well as the interaction between treatment arm and monocytic HLA-DR expression (a marker for immunodepression) at day 1 after stroke onset was independently and highly predictive for post-stroke infections. INTERPRETATION: PANTHERIS suggests that preventive administration of moxifloxacin is superior in reducing infections after severe non-lacunar ischemic stroke compared to placebo. In addition, the results emphasize the pivotal role of immunodepression in developing post-stroke infections. TRIAL REGISTRATION: Controlled-Trials.com ISRCTN74386719

Arthroplasties (with and without bone cement) for proximal femoral fractures in adults

Backround Numerous types of arthroplasties may be used in the surgical treatment of a hip fracture ( proximal femoral fracture). The main differences between the implants are in the design of the stems, whether the stem is fixed in place with or without cement, whether a second articulating joint is included within the prosthesis ( bipolar prosthesis) or whether a partial ( hemiarthroplasty) or total whole hip replacement is used.Objectives To review all randomised controlled trials that have compared different arthroplasties for the treatment of hip fractures in adults.Search strategy We searched the Cochrane Bone, Joint and Muscle Trauma Group Specialised Register ( December 2005), the Cochrane Central Register of Controlled Trials ( T h e Cochrane Library Issue 4, 2005), MEDLINE, EMBASE, the UK National Research Register, several orthopaedic journals, conference proceedings and reference lists of articles.Selection criteria All randomised and quasi-randomised controlled trials comparing different arthroplasties and their insertion with or without cement, for the treatment of hip fractures.Data collection and analysis Two review authors independently assessed trial quality, by use of a ten-item checklist, and extracted data.Main results Seventeen trials involving 1920 patients were included. One trial involved two comparisons. Cemented prostheses, when compared with uncemented ( six trials, 549 participants) were associated with less pain at a year or later ( 16/52 versus 28/52; RR 0.51, 95% CI 0.31 to 0.81) and a tendency to better mobility. No significant difference in surgical complications was found. Comparison of unipolar hemiarthroplasty with bipolar hemiarthroplasty ( seven trials, 857 participants, 863 fractures) showed no significant differences between the two types of implant. Two trials involving 232 patients compared uncemented hemiarthroplasty with a total hip replacement. Both studies reported increased pain for the uncemented prosthesis and one study found better mobility and a lower long-term revision rate for those treated with a THR. Two trials involving 214 participants compared cemented hemiarthroplasty versus total hip replacement. Both trials generally found little difference between prostheses. THR was associated with a slightly longer surgical time but a tendency to better functional outcome in one trial.Authors' conclusions There is limited evidence that cementing a prosthesis in place may reduce post-operative pain and lead to better mobility. There is insufficient evidence to determine the roles of bipolar prostheses and total hip replacement. Further well-conducted randomised trials are required