Detection of gamma-ray emission from the Vela pulsar wind nebula with AGILE.

Pulsars are known to power winds of relativistic particles that can produce bright nebulae by interacting with the surrounding medium. These pulsar wind nebulae are observed by their radio, optical, and x-ray emissions, and in some cases also at TeV (teraelectron volt) energies, but the lack of information in the gamma-ray band precludes drawing a comprehensive multiwavelength picture of their phenomenology and emission mechanisms. Using data from the AGILE satellite, we detected the Vela pulsar wind nebula in the energy range from 100 MeV to 3 GeV. This result constrains the particle population responsible for the GeV emission and establishes a class of gamma-ray emitters that could account for a fraction of the unidentified galactic gamma-ray sources.

Extreme particle acceleration in the microquasar Cygnus X-3.

Super-massive black holes in active galaxies can accelerate particles to relativistic energies, producing jets with associated gamma-ray emission. Galactic 'microquasars', which are binary systems consisting of a neutron star or stellar-mass black hole accreting gas from a companion star, also produce relativistic jets, generally together with radio flares. Apart from an isolated event detected in Cygnus X-1, there has hitherto been no systematic evidence for the acceleration of particles to gigaelectronvolt or higher energies in a microquasar, with the consequence that we are as yet unsure about the mechanism of jet energization. Here we report four gamma-ray flares with energies above 100 MeV from the microquasar Cygnus X-3 (an exceptional X-ray binary that sporadically produces radio jets). There is a clear pattern of temporal correlations between the gamma-ray flares and transitional spectral states of the radio-frequency and X-ray emission. Particle acceleration occurred a few days before radio-jet ejections for two of the four flares, meaning that the process of jet formation implies the production of very energetic particles. In Cygnus X-3, particle energies during the flares can be thousands of times higher than during quiescent states.

Effect of tension-free vaginal tape procedure on urodynamic continence indices.

OBJECTIVE: To assess the difference in measured urethral function before and after tension-free vaginal tape procedure (TVT). METHODS: Women who underwent TVT for genuine stress incontinence with or without intrinsic sphincter deficiency completed this study. Multichannel urodynamic testing was performed preoperatively and 6 weeks postoperatively. Maximum urethral closure pressure and pressure transmission ratio were recorded. Valsalva leak point pressures were determined at 150 mL and at full bladder capacity. Resting and straining urethral angles were measured using the cotton swab technique. Subjects completed both the Incontinence Impact Questionnaire and Urodynamic Distress Inventory preoperatively and postoperatively. RESULTS: Thirty-five consecutive women were studied. Twenty-three (65.7%) had a preoperative diagnosis of intrinsic sphincter deficiency as defined by maximum urethral closure pressure less than 20 cm H(2)O and/or Valsalva leak point pressure less than 60 cm H(2)O. Subjective and objective success rates were 91% and 83%, respectively. Subjects showed an 86.8% (95% CI 71.9%, 100.0%) improvement in their Incontinence Impact Questionnaire score and a 72.9% (95% CI 62.6%, 83.1%) improvement in their Urodynamic Distress Inventory score. The mean change in maximum urethral closure pressure was -1.3 cm H(2)O (95% CI -5.9, 3.3), whereas the pressure transmission ratio increased 15.7% (95% CI 5.0%, 26.3%). The mean decrease in straining urethral angle was 16.3 degrees (95% CI -23.9 degrees, -8.7 degrees ). Cured subjects demonstrating hypermobility preoperatively continued to do so postoperatively. CONCLUSION: There was a significant increase in pressure transmission ratio, but not maximum urethral closure pressure, after TVT. These changes are similar to those reported after retropubic urethropexy and traditional sling procedures. The effectiveness of the TVT sling does not appear to depend on a clinically significant change in the straining urethral angle.

Detrusor biopsy as a potential clinical tool.

Previous published work suggests that electron microscopic findings in bladder biopsies correlate with urodynamic diagnoses of bladder dysfunction in geriatric patients. Our goal was to determine the reproducibility of this previous work and to evaluate the use of detrusor biopsy as a clinical tool in the diagnosis and management in a urogynecology referral population. All patients underwent an initial evaluation, including history, physical examination and urodynamics. Urodynamic evaluation included uroflowmetry, provocative cystometry, instrumented voiding study, urethral profilometry, pressure-flow studies, and evaluation of postvoid residual urine. A cystoscopic-guided detrusor muscle biopsy was obtained from all patients. Each patient was assigned one of four urodynamic diagnoses: detrusor overactivity, obstructed voiding, both overactivity and obstruction, or neither. Each was given a subgroup of normal or ineffective contractility. All detrusor biopsies were evaluated by electron microscopy. Each biopsy was assigned one of four pathologic diagnoses: dysjunction, hypertrophy, both dysjunction and hypertrophy, or neither. Each was given a subgroup of the presence or absence of degeneration. All diagnoses were assigned in a double-blind fashion. All urodynamic and pathologic diagnoses were then compared to determine the percentage agreement. Twenty-six women participated, mean age 52.7 years, range 29-77. Overall agreement among diagnoses was 30% (95% CI 11%-50%). Comparison of each category revealed the following percentage agreements: detrusor overactivity/dysjunction, 52% (95% CI 32%-73%); obstructed voiding/hypertrophy, 78% (95% CI 61%-95%); ineffective contractility/degeneration, 65% (95% CI 45%-85%). The use of detrusor biopsy as a clinical tool was not supported in this population, as demonstrated by the low percentage agreement between urodynamic and pathologic diagnoses. The etiology of bladder dysfunction should be investigated by looking beyond organ-specific structural changes.