The Canadian Seasonal to Interannual Prediction System (CanSIPS) became operational at Environment Canada's Canadian Meteorological Centre (CMC) in December 2011, replacing CMC's previous two-tier ...system. CanSIPS is a two-model forecasting system that combines ensemble forecasts from the Canadian Centre for Climate Modeling and Analysis (CCCma) Coupled Climate Model, versions 3 and 4 (CanCM3 and CanCM4, respectively). Mean climate as well as climate trends and variability in these models are evaluated in freely running historical simulations. Initial conditions for CanSIPS forecasts are obtained from an ensemble of coupled assimilation runs. These runs assimilate gridded atmospheric analyses by means of a procedure that resembles the incremental analysis update technique, but introduces only a fraction of the analysis increment in order that differences between ensemble members reflect the magnitude of observational uncertainties. The land surface is initialized through its response to the assimilative meteorology, whereas sea ice concentration and sea surface temperature are relaxed toward gridded observational values. The subsurface ocean is initialized through surface forcing provided by the assimilation run, together with an offline variational assimilation of gridded observational temperatures followed by an adjustment of the salinity field to preserve static stability. The performance of CanSIPS historical forecasts initialized every month over the period 1981-2010 is documented in a companion paper. The CanCM4 model and the initialization procedures developed for CanSIPS have been employed as well for decadal forecasts, including those contributing to phase 5 of the Coupled Model Intercomparison Project.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, UILJ, UKNU, UL, UM, UPUK
Pancreas allograft acceptance is markedly more selective than other solid organs. The number of pancreata recovered is insufficient to meet the demand for pancreas transplants (PTx), particularly for ...patients awaiting simultaneous kidney‐pancreas (SPK) transplant. Development of a pancreas donor risk index (PDRI) to identify factors associated with an increased risk of allograft failure in the context of SPK, pancreas after kidney (PAK) or pancreas transplant alone (PTA), and to assess variation in allograft utilization by geography and center volume was undertaken. Retrospective analysis of all PTx performed from 2000 to 2006 (n = 9401) was performed using Cox regression controlling for donor and recipient characteristics. Ten donor variables and one transplant factor (ischemia time) were subsequently combined into the PDRI. Increased PDRI was associated with a significant, graded reduction in 1‐year pancreas graft survival. Recipients of PTAs or PAKs whose organs came from donors with an elevated PDRI (1.57–2.11) experienced a lower rate of 1‐year graft survival (77%) compared with SPK transplant recipients (88%). Pancreas allograft acceptance varied significantly by region particularly for PAK/PTA transplants (p < 0.0001). This analysis demonstrates the potential value of the PDRI to inform organ acceptance and potentially improve the utilization of higher risk organs in appropriate clinical settings.
The Pancreas Donor Risk Index identifies factors associated with graft loss following transplantation which appear to differentially affect pancreas allograft survival in isolated transplants compared with simultaneous kidney‐pancreas transplant.
Interstitial fibrosis and tubular atrophy (IFTA) is found in approximately 25% of 1‐year biopsies posttransplant. It is known that IFTA correlates with decreased graft survival when histological ...evidence of inflammation is present. Identifying the mechanistic etiology of IFTA is important to understanding why long‐term graft survival has not changed as expected despite improved immunosuppression and dramatically reduced rates of clinical acute rejection (AR) (Services UDoHaH. http://www.ustransplant.org/annual_reports/current/509a_ki.htm). Gene expression profiles of 234 graft biopsy samples were obtained with matching clinical and outcome data. Eighty‐one IFTA biopsies were divided into subphenotypes by degree of histological inflammation: IFTA with AR, IFTA with inflammation, and IFTA without inflammation. Samples with AR (n = 54) and normally functioning transplants (TX; n = 99) were used in comparisons. A novel analysis using gene coexpression networks revealed that all IFTA phenotypes were strongly enriched for dysregulated gene pathways and these were shared with the biopsy profiles of AR, including IFTA samples without histological evidence of inflammation. Thus, by molecular profiling we demonstrate that most IFTA samples have ongoing immune‐mediated injury or chronic rejection that is more sensitively detected by gene expression profiling. These molecular biopsy profiles correlated with future graft loss in IFTA samples without inflammation.
In this multicenter study featuring gene expression profiles with matching demographic and long‐term follow‐ up data, the authors demonstrate that biopsies with interstitial fibrosis and tubular atrophy without alternative explanations for pathogenesis and regardless of histological reads with or without inflammation, have significantly worse graft survival than those with biopsy‐proven normal transplant histology and differential gene expression changes that indicate ongoing cellular immune‐mediated injury that correlate with worse long‐term outcomes. See Maluf et al's editorial on page 1947.
Although previous consensus recommendations have helped define patients who would benefit from simultaneous liver–kidney transplantation (SLK), there is a current need to reassess published ...guidelines for SLK because of continuing increase in proportion of liver transplant candidates with renal dysfunction and ongoing donor organ shortage. The purpose of this consensus meeting was to critically evaluate published and registry data regarding patient and renal outcomes following liver transplantation alone or SLK in liver transplant recipients with renal dysfunction. Modifications to the current guidelines for SLK and a research agenda were proposed.
The authors report the findings of a summit meeting on simultaneous liver–kidney transplantation, present modifications to the current guidelines and propose directions for future research. See editorial by Feng and Trotter on page 2869.
Absolute quantitation of myocardial blood flow (MBF) by PET is an established method of analyzing coronary artery disease (CAD) but subject to the various shortcomings of available radiotracers. ...Flurpiridaz F 18 is a novel PET radiotracer that exhibits properties of an ideal tracer.
A new absolute perfusion quantitation method with flurpiridaz was developed, taking advantage of the early kinetics and high first-pass extraction by the myocardium of this radiotracer, and the first-in-human measurements of MBF performed in 7 healthy subjects and 8 patients with documented CAD. PET images with time-activity curves were acquired at rest and during adenosine stress.
In healthy subjects, regional MBF between coronary artery territories did not differ significantly, leading to a mean global MBF of 0.73 mL/min/g at rest and 2.53 mL/min/g during stress, with a mean global myocardial flow reserve (MFR) of 3.70. CAD vascular territories with <50% stenosis demonstrated a mean MBF of 0.73 at rest and 2.02 during stress, leading to a mean MFR of 2.97. CAD vascular territories with ≥50% stenosis exhibited a mean MBF of 0.86 at rest and 1.43 during stress, leading to a mean MFR of 1.86. Differences in stress MBF and MFR between normal and CAD territories, as well as between <50% and ≥50% stenosis vascular territories, were significant (P < 0.01).
Absolute quantitation of MBF in humans with the novel PET radiotracer flurpiridaz is feasible over a wide range of cardiac flow in the presence or absence of stress-inducible myocardial ischemia. The significant decrease in stress MBF and ensuing MFR in CAD territories allows a clear distinction between vascular territories exhibiting stress-inducible myocardial ischemia and those with normal perfusion.
A consensus conference sponsored by the American Society of Transplant Surgeons (ASTS), American Society of Transplantation (AST), United Network for Organ Sharing (UNOS) and American Society of ...Nephrology (ASN) convened to examine simultaneous liver‐kidney transplantation (SLK). Directors from the 25 largest liver transplant programs along with speakers with recognized expertise attended. The purposes of this conference were to propose indications for SLK, to establish a prospective data registry and, most importantly, to recommend standard listing criteria for these patients. Scientific registry of transplant recipients data, and single center data regarding chronic kidney disease (CKD) and acute kidney injury (AKI) in conjunction with liver failure as a basis for SLK was presented and discussed. The consensus was that Regional Review Boards (RRB) should determine listing for SLK, as with other MELD exceptions, with automatic approval for: (i) End‐stage renal disease with cirrhosis and symptomatic portal hypertension or hepatic vein wedge pressure gradient ≥ 10 mm Hg (ii) Liver failure and CKD with GFR ≤ 30 mL/min (iii) AKI or hepatorenal syndrome with creatinine ≥ 2.0 mg/dL and dialysis ≥ 8 weeks (iv) Liver failure and CKD and biopsy demonstrating > 30% glomerulosclerosis or 30% fibrosis. The RRB would evaluate all other requests to determine appropriateness.
This report highlights the most recent data on simultaneous liver‐ kidney transplantation and consensus on indications and recommendations for standardized listing criteria for patients with severe renal and liver disease being considered for combined transplants.
We examined factors associated with expanded criteria donor (ECD) kidney discard. Scientific Registry of Transplant Recipients (SRTR)/Organ Procurement and Transplantation Network (OPTN) data were ...examined for donor factors using logistic regression to determine the adjusted odds ratio (AOR) of discard of kidneys recovered between October 1999 and June 2005. Logistic and Cox regression models were used to determine associations with delayed graft function (DGF) and graft failure. Of the 12 536 recovered ECD kidneys, 5139 (41%) were discarded. Both the performance of a biopsy (AOR = 1.21, p = 0.02) and the degree of glomerulosclerosis (GS) on biopsy were significantly associated with increased odds of discard. GS was not consistently associated with DGF or graft failure. The discard rate of pumped ECD kidneys was 29.7% versus 43.6% for unpumped (AOR = 0.52, p < 0.0001). Among pumped kidneys, those with resistances of 0.26–0.38 and >0.38 mmHg/mL/min were discarded more than those with resistances of 0.18–0.25 mmHg/mL/min (AOR = 2.5 and 7.9, respectively). Among ECD kidneys, pumped kidneys were less likely to have DGF (AOR = 0.59, p < 0.0001) but not graft failure (RR = 0.9, p = 0.27). Biopsy findings and machine perfusion are important correlates of ECD kidney discard; corresponding associations with graft failure require further study.
This registry based analysis of factors associated with expanded criteria donor (ECD) kidney discard found that both the performance of a biopsy and the degree of glomerulosclerosis on biopsy were significantly associated with an increased odds of discard; also the discard rate of pumped ECD kidneys was lower than for unpumped. See also editorial by Cecka and Gritsch in this issue on page 735.
Using primarily postoperative laboratory parameters, Al‐Freah et al (page 1255) report a model to predict liver transplant primary nonfunction that significantly improves upon current definitions.
Highly textured ZnO cones have been grown onto glass substrates by chemical bath deposition (CBD) method. They were given heat treatment at 623
K for 2
h in air. The change in structural, optical and ...electrical properties were studied by means of X-ray diffraction (XRD), scanning electron microscopy (SEM), optical absorption, electrical resistivity and contact angle measurements. Structural analysis by X-ray diffraction pattern showed as-deposited ZnO film has high-orientation along
c-direction (0
0
2), which remained the same with low-intensity after heat treatment. Well-defined cones almost perpendicular to substrate surface, which were slightly compressed in size after heat treatment, have been detected through SEM micrographs. Water wettability study revealed a contact angle of 72.28
±
1.5° for as-deposited ZnO films, whereas hydrophobic surface with a contact angle of 152.84
±
1.5° was obtained after heat treatment. This is attributed to the topographical change in structural morphology. Change in bandgap energy from 3.7 to 3.2
eV was observed after heat treatment. Electrical resistivity measurement showed semiconducting nature with room temperature resistivity 10
4
Ω
cm for as-deposited ZnO, which was decreased to 10
3
Ω
cm for annealed ZnO film.
Background and Aims: Severe acute respiratory syndrome (SARS) is a virulent viral infection that affects a number of organs and systems. This study examined if SARS may result in cardiovascular ...complications. Methods and Results: 121 patients (37.5 (SD13.2) years, 36% male) diagnosed to have SARS were assessed continuously for blood pressure, pulse, and temperature during their stay in hopsital. Hypotension occurred in 61 (50.4%) patients in hospital, and was found in 28.1%, 21.5%, and 14.8% of patients during the first, second, and third week, respectively. Only one patient who had transient echocardiographic evidence of impaired left ventricular systolic function required temporary inotropic support. Tachycardia was present in 87 (71.9%) patients, and was found in 62.8%, 45.4%, and 35.5% of patients from the first to third week. It occurred independent of hypotension, and could not be explained by the presence of fever. Tachycardia was also present in 38.8% of patients at follow up. Bradycardia only occurred in 18 (14.9%) patients as a transient event. Reversible cardiomegaly was reported in 13 (10.7%) patients, but without clinical evidence of heart failure. Transient atrial fibrillation was present in one patient. Corticosteroid therapy was weakly associated with tachycardia during the second (χ2 = 3.99, p = 0.046) and third week (χ2 = 6.53, p = 0.01), although it could not explain tachycardia during follow up. Conclusions: In patients with SARS, cardiovascular complications including hypotension and tachycardia were common but usually self limiting. Bradycardia and cardiomegaly were less common, while cardiac arrhythmia was rare. However, only tachycardia persisted even when corticosteroid therapy was withdrawn.
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