Peatland Initiation, Carbon Accumulation, and 2 ka Depth in the James Bay Lowland and Adjacent Regions

Copyright © 2014 University of Colorado at Boulder, Institute of Arctic and Alpine ResearchPeatlands surrounding Hudson and James Bays form the second largest peatland complex in the world and contain major stores of soil carbon (C). This study utilized a transect of eight ombrotrophic peat cores from remote regions of central and northern Ontario to quantify the magnitude and rate of C accumulation since peatland initiation and for the past 2000 calendar years before present (2 ka). These new data were supplemented by 17 millennially resolved chronologies from a literature review covering the Boreal Shield, Hudson Plains, and Taiga Shield bordering Hudson and James Bays. Peatlands initiated in central and northern Ontario by 7.8 ka following deglaciation and isostatic emergence of northern areas to above sea level. Total C accumulated since inception averaged 109.7 ± (std. dev.) 36.2 kg C m–2. Approximately 40% of total soil C has accumulated since 2 ka at an average apparent rate of 20.2 ± 6.9 g C m–2 yr–1. The 2 ka depths correlate significantly and positively with modern gridded climate estimates for mean annual precipitation, mean annual air temperature, growing degree-days > 0 °C, and photosynthetically active radiation integrated over days > 0 °C. There are significantly shallower depths in permafrost peatlands. Vertical peat accumulation was likely constrained by temperature, growing season length, and photosynthetically active radiation over the last 2 ka in the Hudson Bay Lowlands and surrounding regions.US National Science Foundatio

Sacral Neuromodulation for Refractory Urge Incontinence Is Less Effective Following Spinal Surgery

Patients with neurogenic disorders and voiding dysfunction have been reported to respond poorly to sacral neuromodulation. We report on our experience in treating voiding symptoms with sacral neuromodulation after spinal surgery. The medical charts of patients evaluated for sacral neuromodulation from 2000–2008 were retrospectively reviewed. Indications, need for explantation, and clinical success (>50% symptom improvement) were recorded. The cohort of patients who had undergone prior spinal surgery was compared to patients with no history of spinal surgery or neurological disease. Thirty-two patients with a history of spinal surgery and 136 with no history of neurologic disease underwent sacral neuromodulation testing. Twenty men and women (62.5%) from the spinal surgery group ultimately underwent permanent implantation. Seventeen of the 32 patients were diagnosed with urge incontinence, of whom 52.9% reported a successful outcome at a mean of 2.3 years of follow-up, compared to an 80.3% success rate in patients with no history of spinal surgery (p = 0.018). Sixteen of 32 carried a diagnosis of urgency/frequency with 62.5% success at last follow-up, compared 73.9% (p = 0.35) of those without a history of spinal surgery or neurological disease. Thirteen of 32 patients diagnosed with urinary retention experienced a 61.5% long-term success rate, compared with 63.6% for those without spinal surgery and urinary retention. Six of 20 (30.0%) in the spinal surgery group were explanted at a mean time of 2.9 years, compared with 27 of 102 (26.5%) of the non-neurologic patients. Clinical success can be achieved using sacral neuromodulation in patients with voiding dysfunction and a history of spinal surgery; however, those with urge incontinence are less likely to report significant improvement

Buccal Mucosal Graft Urethroplasty

At our institution, the majority of buccal mucosal graft urethroplasties are performed using a two-team approach with an otolaryngologic surgeon. We report our two-surgeon experience with buccal mucosal grafting for reconstruction of all anterior urethral strictures. Twenty-four men underwent autologous buccal mucosal graft urethroplasty between October 2001 and September 2008 for recurrent urethral stricture disease. Twenty-two underwent a single-stage repair and two underwent a two-stage repair. Medical charts were retrospectively reviewed for demographics, comorbidities, etiology, location and length of stricture, and prior interventions in order to identify predictors of buccal urethroplasty success, defined as no evidence of stricture recurrence. All patients underwent retrograde urethrogram and cystoscopy. Operative and anesthesia times were evaluated. We determined an overall success rate of 83.3% (20 of 24 cases). Mean anesthesia time for single-stage urethroplasty was 155 min and mean operative time was 123 min. One of the two two-stage urethroplasties experienced stricture recurrence (50%). The single-stage buccal graft success rate was 86.4% (19 of 22 cases). Two of the four who developed recurrent stricture disease that required intervention had undergone a previous mesh urethroplasty. Complications developed in four of 24 patients (16.6%), including superficial wound infection (one), superficial wound dehiscence (two), and abscess/fistula formation requiring reoperation (one). The buccal mucosa is an ideal tissue for both single- and two-stage substitution urethroplasty for patients with recurrent stricture disease. Our two-surgeon technique minimizes anesthesia and operative times, and contributes to the overall high success rate and relatively low complication rate

Accuracy of subjective vesicoureteral reflux timing assessment: supporting new voiding cystourethrogram guidelines.

BACKGROUND: Bladder volume at the onset of vesicoureteral reflux (VUR) is an important prognostic indicator of spontaneous resolution and the risk of pyelonephritis. OBJECTIVE: We aim to determine whether pediatric urologists and pediatric radiologists can accurately estimate the timing of reflux by examining voiding cystourethrogram (VCUG) images without prior knowledge of the instilled contrast volume. MATERIALS AND METHODS: Total bladder volume and the volume at the time of reflux were collected from VCUG reports to determine the volume at the onset of VUR. Thirty-nine patients were sorted into three groups: early-/mid-filling reflux, late-filling and voiding only. Thirty-nine images were shown to three pediatric urologists and two pediatric radiologists in a blinded fashion and they were then asked to estimate VUR timing based on the above categories. A weighted kappa statistic was calculated to assess rater agreement with the gold standard volume-based report of VUR timing. RESULTS: The mean patient age at VCUG was 3.1±2.9 months, the median VUR was grade 3, and 20 patients were female. Overall agreement among all five raters was moderate (k=0.43, 95% confidence interval [CI] 0.36-0.50). Individual agreement between rater and gold standard was slight to moderate with kappa values ranging from 0.13 to 0.43. CONCLUSION: Pediatric radiologists and urologists are unable to accurately and reliably characterize VUR timing on fluoroscopic VCUG. These findings support the recently published American Academy of Pediatrics protocol recommending the routine recording of bladder volume at the onset of VUR as a standard component of all VCUGs to assist in a more accurate assessment of the likelihood of resolution and risk of recurrent urinary tract infections