Laser beam self-symmetrization in air in the multifilamentation regime

We show experimental and numerical evidence of spontaneous self-symmetrization of focused laser beams experiencing multi-filamentation in air. The symmetrization effect is observed as the multiple filaments generated prior to focus approach the focal volume. This phenomenon is attributed to the nonlinear interactions amongst the different parts of the beam mediated by the optical Kerr effect, which leads to a symmetric redistribution of the wave vectors even when the beam consists of a bundle of many filaments.Comment: 9 pages, 7 figure

Evolution of Endoscopic Lesions in Steroid-Refractory Acute Severe Ulcerative Colitis Responding to Infliximab or Cyclosporine

BACKGROUND/AIMS: Few data on the evolution of endoscopic findings are available in patients with acute severe ulcerative colitis (ASUC). The aim of this study was to describe this evolution in a prospective cohort. METHODS: Patients admitted for a steroid-refractory ASUC and included in a randomized trial comparing infliximab and cyclosporine were eligible if they achieved steroid-free clinical remission at day 98. Flexible sigmoidoscopies were performed at baseline, days 7, 42 and 98. Ulcerative colitis endoscopic index of severity (UCEIS) and its sub-scores - vascular pattern, bleeding and ulceration/erosion - were post-hoc calculated. Global endoscopic remission was defined by a UCEIS of 0, and partial endoscopic remission by any UCEIS sub-score of 0. RESULTS: Among the 55 patients analyzed (29 infliximab and 26 cyclosporine), 49 (83%) had UCEIS >= 6 at baseline at baseline. Partial endoscopic remission rates were higher for bleeding than for vascular pattern and for ulcerations/erosions at day 7 (20% vs. 4% and 5% (n = 55); p CONCLUSION: In steroid-refractory ASUC patients responding to a second-line medical therapy, endoscopic remission process started with bleeding remission and was not achieved in half the patients at day 98 for vascular pattern. Infliximab provided a higher endoscopic remission rate than cyclosporine at day 98.Peer reviewe

Ciclosporin versus infliximab in patients with severe ulcerative colitis refractory to intravenous steroids: a parallel, open-label randomised controlled trial.

International audienceBACKGROUND: Ciclosporin and infliximab are potential rescue treatments to avoid colectomy in patients with acute severe ulcerative colitis refractory to intravenous corticosteroids. We compared the efficacy and safety of these drugs for this indication. METHODS: In this parallel, open-label, randomised controlled trial, patients were aged at least 18 years, had an acute severe flare of ulcerative colitis defined by a Lichtiger score greater than 10 points, and had been given an unsuccessful course of high-dose intravenous steroids. None of the patients had previously received ciclosporin or infliximab. Between June 1, 2007, and Aug 31, 2010, patients at 27 European centres were randomly assigned (via computer-derived permutation tables; 1:1) to receive either intravenous ciclosporin (2 mg/kg per day for 1 week, followed by oral drug until day 98) or infliximab (5 mg/kg on days 0, 14, and 42). In both groups, azathioprine was started at day 7 in patients with a clinical response. Neither patients nor investigators were masked to study treatment. The primary efficacy outcome was treatment failure defined by absence of a clinical response at day 7, a relapse between day 7 and day 98, absence of steroid-free remission at day 98, a severe adverse event leading to treatment interruption, colectomy, or death. Analysis was by intention to treat. This trial is registered with EudraCT (2006-005299-42) and ClinicalTrials.gov (NCT00542152). FINDINGS: 115 patients were randomly assigned; 58 patients were allocated to receive ciclosporin and 57 to receive infliximab. Treatment failure occurred in 35 (60%) patients given ciclosporin and 31 (54%) given infliximab (absolute risk difference 6%; 95% CI -7 to 19; p=0*52). Nine (16%) patients in the ciclosporin group and 14 (25%) in the infliximab group had severe adverse events. INTERPRETATION: Ciclosporin was not more effective than infliximab in patients with acute severe ulcerative colitis refractory to intravenous steroids. In clinical practice, treatment choice should be guided by physician and centre experience. FUNDING: Association François Aupetit, Société Nationale Française de Gastroentérologie, and the International Organization for the study of Inflammatory Bowel Disease

High Risk of Anal and Rectal Cancer in Patients With Anal and/or Perianal Crohn’s Disease

International audienceBackground & AimsLittle is known about the magnitude of the risk of anal and rectal cancer in patients with anal and/or perineal Crohn’s disease. We aimed to assess the risk of anal and rectal cancer in patients with Crohn’s perianal disease followed up in the Cancers Et Surrisque Associé aux Maladies Inflammatoires Intestinales En France (CESAME) cohort.MethodsWe collected data from 19,486 patients with inflammatory bowel disease (IBD) enrolled in the observational CESAME study in France, from May 2004 through June 2005; 14.9% of participants had past or current anal and/or perianal Crohn’s disease. Subjects were followed up for a median time of 35 months (interquartile range, 29–40 mo). To identify risk factors for anal cancer in the total CESAME population, we performed a case-control study in which participants were matched for age and sex.ResultsAmong the total IBD population, 8 patients developed anal cancer and 14 patients developed rectal cancer. In the subgroup of 2911 patients with past or current anal and/or perianal Crohn’s lesions at cohort entry, 2 developed anal squamous-cell carcinoma, 3 developed perianal fistula–related adenocarcinoma, and 6 developed rectal cancer. The corresponding incidence rates were 0.26 per 1000 patient-years for anal squamous-cell carcinoma, 0.38 per 1000 patient-years for perianal fistula–related adenocarcinoma, and 0.77 per 1000 patient-years for rectal cancer. Among the 16,575 patients with ulcerative colitis or Crohn’s disease without anal or perianal lesions, the incidence rate of anal cancer was 0.08 per 1000 patient-years and of rectal cancer was 0.21 per 1000 patient-years. Among factors tested by univariate conditional regression (IBD subtype, disease duration, exposure to immune-suppressive therapy, presence of past or current anal and/or perianal lesions), the presence of past or current anal and/or perianal lesions at cohort entry was the only factor significantly associated with development of anal cancer (odds ratio, 11.2; 95% CI, 1.18-551.51; P = .03).ConclusionsIn an analysis of data from the CESAME cohort in France, patients with anal and/or perianal Crohn’s disease have a high risk of anal cancer, including perianal fistula–related cancer, and a high risk of rectal cancer