An enhanced approach for the use of satellite-derived leaf area index values in dry deposition modeling in the Athabasca oil sands region.

In the Athabasca oil sands region (AOSR) of Northern Alberta, the dry deposition of sulphur and nitrogen compounds represents a major fraction of total (wet plus dry) deposition due to oil sands emissions. The leaf area index (LAI) is a critical parameter that affects the dry deposition of these gaseous and particulate compounds to the surrounding boreal forest canopy. For this study, LAI values based on Moderate Resolution Imaging Spectroradiometer satellite imagery were obtained and compared to ground-based measurements, and two limitations with the satellite data were identified. The satellite LAI data firstly represents one-sided LAI values that do not account for the enhanced LAI associated with needle leaf geometry, and secondly, underestimates LAI in winter-time northern latitude regions. An approach for adjusting satellite LAI values for different boreal forest cover types, as a function of time of year, was developed to produce more representative LAI values that can be used by air quality sulphur and nitrogen deposition models. The application of the approach increases the AOSR average LAI for January from 0.19 to 1.40, which represents an increase of 637%. Based on the application of the CALMET/CALPUFF model system, this increases the predicted regional average dry deposition of sulphur and nitrogen compounds for January by factors of 1.40 to 1.30, respectively. The corresponding AOSR average LAI for July increased from 2.8 to 4.0, which represents an increase of 43%. This increases the predicted regional average dry deposition of sulphur and nitrogen compounds for July by factors of 1.28 to 1.22, respectively. These findings reinforce the importance of the LAI metric for predicting the dry deposition of sulphur and nitrogen compounds. While satellite data can provide enhanced spatial and temporal resolution, adjustments are identified to overcome associated limitations. This work is considered to have application for other deposition model studies where dry deposition represents a significant fraction of total deposition.

Subtotal hepatectomy and whole graft auxiliary transplantation for acetaminophen-associated acute liver failure.

BACKGROUND: An acetominophen overdose (AOD) is the leading cause of acute liver failure (ALF) in the UK and USA. For patients who meet the King's College Hospital criteria, (mortality risk > 85%), an emergency orthotopic liver transplantation (OLT) is conventionally performed with subsequent life-long immunosuppression. A new technique was developed in 1998 for AOD-induced ALF where a subtotal hepatectomy (right hepatic trisectionectomy) and whole graft auxiliary liver transplant (WGALT) was performed with complete withdrawal of immunosupression during the first year post-operatively. RESULTS: During 1998-2010, 68 patients were listed for an emergency transplantation for AOD ALF at our institution: 28 died waiting, 16 underwent OLT and 24 a subtotal hepatectomy with WGALT. Eight OLT (50%) and 16 WGALT remain alive (67%); actuarial survival at 5 years OLT 50%, WGALT 63%, P = 0.37. All patients who had successful WGALT are off immunosuppression. Poor prognostic factors in the WGALT group included higher donor age (40.4 versus 53.9, P = 0.043), requirements for a blood transfusion (4.3 versus 7.6, P = 0.0043) and recipient weight (63.1 versus 54 kg, P = 0.036). CONCLUSION: Although OLT remains standard practice for AOD-induced ALF, life-long immunosuppression is required. A favourable survival rate using a subtotal hepatectomy and WGALT has been demonstrated, and importantly, all successful patients have undergone complete immunosuppression withdrawal. This technique is advocated for patients who have acetominophen hepatotoxicity requiring liver transplantation.

Liver transplantation following donation after cardiac death: an analysis using matched pairs.

Grafts from donation after cardiac death (DCD) donors are used to increase the number of organs available for liver transplantation. There is concern that warm ischemia may impair graft function. We compared our DCD recipients with a case-matched group of donation after brain death (DBD) recipients. Between January 2002 and April 2008, 39 DCD grafts were transplanted. These were matched with 39 DBD recipients on the basis of identified variables that had a significant impact on mortality. These were used to individually match DCD and DBD patients with similar predictive mortality. We compared patient/graft survival, primary non-function (PNF), and rates of complications. Of all liver transplants, 6.1% were DCD grafts. PNF occurred twice in the DCD group. The incidence of nonanastomotic biliary strictures (NABS; 20.5% versus 0%, P = 0.005) and hepatic artery stenosis (HAS; 12.8% versus 0%, P = 0.027) in the DCD group was higher. One-year (79.5% versus 97.4%, P = 0.029) and 3-year (63.6% versus 97.4%, P = 0.001) graft survival was lower in the DCD group. Three-year patient survival was also lower (68.2% versus 100%, P < 0.0001). Our study is the first to use case-matched patients and compare groups with similar predictive mortality. There was a higher incidence of NABS and HAS in the DCD group. NABS were likely a result of warm ischemia. HAS may have been due to ischemia or arterial injury during retrieval. The DCD group had significantly poorer outcomes, but DCD grafts remain a valuable resource. With careful donor/recipient selection, minimization of ischemia, and good postoperative care, acceptable results can be achieved.

Impact of Regional Organ Sharing and Allocation in the UK Northern Liver Alliance on Waiting Time to Liver Transplantation and Waitlist Survival.

BACKGROUND: In the United Kingdom, liver transplantation (LT) is undertaken in 7 supraregional centers. Until March 2018, liver grafts were offered to a center and allocated to a patient on their elective waiting list (WL) based on unit prioritization. Patients in Newcastle, Leeds, and Edinburgh with a United Kingdom Model for End-Stage Liver Disease (UKELD) score ≥62 were registered on a common WL and prioritized for deceased-donor liver allocation. This was known as the Northern Liver Alliance (NLA) "top-band scheme." Organs were shared between the 3 centers, with a "payback" scheme ensuring no patient in any center was disadvantaged. We investigated whether the NLA had improved WL survival and waiting time (WT) to transplantation. METHODS: Data for this study were obtained from the UK Transplant Registry maintained by National Health Service Blood and Transplant. This study was based on adult patients registered for first elective liver transplant between April 2013 and December 2016. Non-NLA centers were controls. The Kaplan-Meier method was used to estimate WL survival and median WT to transplant, with the log-rank test used to make comparisons; a Bonferroni correction was applied post hoc to determine pairwise differences. RESULTS: WT was significantly lower at NLA centers compared with non-NLA centers for top-band patients (23 versus 99 days, P < 0.001). However, WL survival was not significantly different for top-band patients (P > 0.999) comparing NLA with non-NLA centers. WL survival for nontop-band patients was no different (P > 0.999) comparing NLA with non-NLA centers. CONCLUSIONS: The NLA achieved its aim, providing earlier transplantation to patients with the greatest need. Nontop-band patients did not experience inferior survival.

Solitary main pancreatic ductal calculus of possible biliary origin causing acute pancreatitis.

CONTEXT: Pancreatic ductal calculi are most often associated with chronic pancreatitis. Radiological features of chronic pancreatitis are readily evident in the presence of these calculi. However, acute pancreatitis due to a solitary main pancreatic ductal calculus of biliary origin is rare. CASE REPORT: A 59-year-old man presented with a first episode of acute pancreatitis. Contrast enhanced computerized tomography (CT) scan and endoscopic retrograde cholangiopancreatography (ERCP) revealed a calculus in the main pancreatic duct in the head of the pancreas causing acute pancreatitis. There were no features suggestive of chronic pancreatitis on CT scanning. The episode acute pancreatitis was managed conservatively. ERCP extraction of the calculus failed as the stone was impacted in the main pancreatic duct resulting in severe acute pancreatitis. Once this resolved, a transduodenal exploration and extraction of the pancreatic ductal calculus was performed successfully. Crystallographic analysis revealed the composition of the calculus was different to that seen in chronic pancreatitis, but more in keeping with a calculus of biliary origin. This could be explained by migration of the biliary calculus via the common channel into the main pancreatic duct. Following the operation the patient made an uneventful recovery and was well at two-year follow up. CONCLUSION: Acute pancreatitis due to a solitary main pancreatic ductal calculus of biliary origin is rare. Failing endoscopic extraction, transduodenal exploration and extraction is a safe option after resolution of acute pancreatitis.

Improving cytopenia with splenic artery embolization in a patient with paroxysmal nocturnal hemoglobinuria on eculizumab.

Paroxysmal nocturnal hemoglobinuria is a rare acquired stem cell disorder characterized by intravascular hemolysis, aplasia and an increased risk of thrombosis. We describe a patient under treatment with the anti-complement antibody eculizumab who developed pancytopenia, requiring blood transfusions, due to massive splenomegaly. The patient underwent two separate splenic embolizations, which reduced the size of the spleen and improved his blood count to the point that blood transfusions were no longer necessary. Splenic embolization was chosen over splenectomy due to the potential postoperative complications of splenectomy, especially that of thrombosis.

Dense fine-mapping study identifies new susceptibility loci for primary biliary cirrhosis.

We genotyped 2,861 cases of primary biliary cirrhosis (PBC) from the UK PBC Consortium and 8,514 UK population controls across 196,524 variants within 186 known autoimmune risk loci. We identified 3 loci newly associated with PBC (at P<5×10(-8)), increasing the number of known susceptibility loci to 25. The most associated variant at 19p12 is a low-frequency nonsynonymous SNP in TYK2, further implicating JAK-STAT and cytokine signaling in disease pathogenesis. An additional five loci contained nonsynonymous variants in high linkage disequilibrium (LD; r2>0.8) with the most associated variant at the locus. We found multiple independent common, low-frequency and rare variant association signals at five loci. Of the 26 independent non-human leukocyte antigen (HLA) signals tagged on the Immunochip, 15 have SNPs in B-lymphoblastoid open chromatin regions in high LD (r2>0.8) with the most associated variant. This study shows how data from dense fine-mapping arrays coupled with functional genomic data can be used to identify candidate causal variants for functional follow-up.

Budd-Chiari syndrome--a review of the diagnosis and management.

Budd-Chiari syndrome (BCS) is the liver disease resulting from hepatic venous outflow obstruction comprising a triad of abdominal discomfort, hepatomegaly and ascites. Advances in the management of this disorder over the last three decades have dramatically improved survival. We present a review of the management of BCS followed by a case which illustrates some key points in the diagnosis and treatment of this condition.

Epstein-Barr virus infection and central nervous system involvement after orthoptic liver transplant.

Epstein-Barr virus (EBV) infection presenting as encephalitis in seronegative adults in the context of solid organ transplantation is rarely reported. EBV seroconversion illnesses in the adult population after organ transplantation are quite uncommon. This report describes a case of encephalitis due to EBV infection after liver transplantation in an adult patient. The patient was seronegative for EBV pretransplant. She showed persistent viral replication indicated by high levels of EBV DNA in the serum, which raised concerns for future development of post-transplant lymphoproliferative disorder. The report discusses the management of such patients, awareness of EBV infection and earlier diagnosis by use of EBV PCR in adult immunocompromised individuals where infection may cause particular problems.

Emergency subtotal hepatectomy: a new concept for acetaminophen-induced acute liver failure: temporary hepatic support by auxiliary orthotopic liver transplantation enables long-term success.

INTRODUCTION: Acetaminophen (paracetamol) overdose (AOD) has recently emerged as the leading cause of acute liver failure (ALF) in the United States, with an incidence approaching that seen in the United Kingdom. We describe a new way to treat AOD ALF patients fulfilling King's College criteria for "super-urgent" liver transplantation. METHODS: Beginning in June 1998, we have been piloting a clinical program of subtotal hepatectomy and auxiliary orthotopic liver transplantation (ALT) for AOD ALF. Our technique is based on the following principles: (1) subtotal hepatectomy; (2) auxiliary transplantation of a whole liver graft; (3) gradual withdrawal of immunosuppression after recovery. Results were compared with patients who had undergone an orthotopic liver transplantation (OLT) for AOD ALF in the same period. Quality of life comparisons were made using the SF36 questionnaire. RESULTS: Thirteen patients underwent this procedure between June 1998 and March 2005. Median survival is 68 months (range, 0-102 m). Actual survival data show that 9 of 13 patients are alive (69%) compared with 7 of 13 OLT patients (54%). One ALT patient required a retransplantation with an OLT due to hepatic vein thrombosis, and immunosuppression is therefore maintained. The other 8 surviving ALT patients are off immunosuppression. These 8 ALT patients have normal liver function and have a better quality of life compared with the 7 surviving OLT patients. CONCLUSION: Our results with this new technique are encouraging: 69% actual survival, no long-term immunosuppression requirement, and improved quality of life in the 62% successful cases.

The value of MELD and sodium in assessing potential liver transplant recipients in the United Kingdom.

As the result of the widening gap between supply and demand of organs for liver transplantation, efforts to improve allocation have become an increasingly important yet controversial subject. The MELD score has been adopted in the USA but its usefulness has rarely been examined in Europe. We carried out an intention to treat analysis of 422 patients placed on our transplant waiting list over a 5-year period. We examined multiple variables to investigate the value of MELD, sodium and other factors in predicting post-transplant outcomes. MELD at transplant was the most important indicator of post-transplant outcomes. In addition, delta-MELD and hyponatreamia were significant at predicting, which patients placed on the waiting list would not proceed to transplant. While a move to allocating solely by MELD is not justified in the UK allocation system, there is value in using MELD, delta-MELD and hyponatreamia in making decisions regarding the allocation of organs. This may subsequently help to improve overall outcomes.

Bile duct strictures after hepatobiliary surgery: assessment with MR cholangiography.

PURPOSE: To establish the accuracy of magnetic resonance (MR) cholangiography for diagnosis of postsurgical bile duct strictures. MATERIALS AND METHODS: Sixty-seven patients suspected of having bile duct strictures after liver transplantation (n = 54), cholecystectomy (n = 8), hepatic resection (n = 4), or pancreaticoduodenectomy (n = 1) underwent MR cholangiography. Thick-slab single-shot fast spin-echo (repetition time msec/echo time msec, 4,500/940) imaging was performed in the coronal through sagittal planes with rotation in 10 degrees increments, and contiguous thin-section images were obtained in the transverse and the optimal coronal oblique planes by using half-Fourier rapid acquisition with relaxation enhancement (1,900/96). Three blinded observers independently reviewed the MR images and recorded diagnostic features including presence of biliary stricture by using a five-point confidence scale. Receiver operating characteristic analysis was used to measure the accuracy of MR cholangiography. Sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) were calculated. Final diagnosis was established at surgery (n = 29) and direct cholangiography (23 of 29) or at direct cholangiography, liver biopsy, and/or serial liver function tests (n = 38). RESULTS: Thirty-three of 67 patients had strictures confirmed with the reference standard. MR cholangiography enabled correct diagnosis and depicted the site of strictures in all cases. Findings of stricture at MR cholangiography were false-positive in five patients with moderate duct dilatation and caliber change at the level of the anastomosis. Mean accuracy, sensitivity, specificity, PPV, and NPV were 94%, 97%, 74%, 86%, and 96%, respectively. CONCLUSION: MR cholangiography is as sensitive as direct cholangiography for the assessment of bile duct strictures after hepatobiliary surgery but may lead to overestimation of the importance of duct dilatation and caliber change.