Oxygen-insensitive nitroreductase E. coli NfsA, but not NfsB, is inhibited by fumarate

Escherichia coli NfsA and NfsB are founding members of two flavoprotein families that catalyze the oxygen-insensitive reduction of nitroaromatics and quinones by NAD(P)H. This reduction is required for the activity of nitrofuran antibiotics and the enzymes have also been proposed for use with nitroaromatic prodrugs in cancer gene therapy and biocatalysis, but the roles of the proteins in vivo in bacteria are not known. NfsA is NADPH-specific whereas NfsB can also use NADH. The crystal structures of E. coli NfsA and NfsB and several analogs have been determined previously. In our crystal trials, we unexpectedly observed NfsA bound to fumarate. We here present the X-ray structure of the E. coli NfsA-fumarate complex and show that fumarate acts as a weak inhibitor of NfsA but not of NfsB. The structural basis of this differential inhibition is conserved in the two protein families and occurs at fumarate concentrations found in vivo, so impacting the efficacy of these proteins.

Structure and Dynamics of Three Escherichia coli NfsB Nitro-Reductase Mutants Selected for Enhanced Activity with the Cancer Prodrug CB1954

Escherichia coli NfsB has been studied extensively for its potential for cancer gene therapy by reducing the prodrug CB1954 to a cytotoxic derivative. We have previously made several mutants with enhanced activity for the prodrug and characterised their activity in vitro and in vivo. Here, we determine the X-ray structure of our most active triple and double mutants to date, T41Q/N71S/F124T and T41L/N71S. The two mutant proteins have lower redox potentials than wild-type NfsB, and the mutations have lowered activity with NADH so that, in contrast to the wild-type enzyme, the reduction of the enzyme by NADH, rather than the reaction with CB1954, has a slower maximum rate. The structure of the triple mutant shows the interaction between Q41 and T124, explaining the synergy between these two mutations. Based on these structures, we selected mutants with even higher activity. The most active one contains T41Q/N71S/F124T/M127V, in which the additional M127V mutation enlarges a small channel to the active site. Molecular dynamics simulations show that the mutations or reduction of the FMN cofactors of the protein has little effect on its dynamics and that the largest backbone fluctuations occur at residues that flank the active site, contributing towards its broad substrate range.

Dragon 1 Protocol Manuscript: Training, Accreditation, Implementation and Safety Evaluation of Portal and Hepatic Vein Embolization (PVE/HVE) to Accelerate Future Liver Remnant (FLR) Hypertrophy

STUDY PURPOSE

The DRAGON 1 trial aims to assess training, implementation, safety and feasibility of combined portal- and hepatic-vein embolization (PVE/HVE) to accelerate future liver remnant (FLR) hypertrophy in patients with borderline resectable colorectal cancer liver metastases.

METHODS

The DRAGON 1 trial is a worldwide multicenter prospective single arm trial. The primary endpoint is a composite of the safety of PVE/HVE, 90-day mortality, and one year accrual monitoring of each participating center. Secondary endpoints include: feasibility of resection, the used PVE and HVE techniques, FLR-hypertrophy, liver function (subset of centers), overall survival, and disease-free survival. All complications after the PVE/HVE procedure are documented. Liver volumes will be measured at week 1 and if applicable at week 3 and 6 after PVE/HVE and follow-up visits will be held at 1, 3, 6, and 12 months after the resection.

RESULTS

Not applicable.

CONCLUSION

DRAGON 1 is a prospective trial to assess the safety and feasibility of PVE/HVE. Participating study centers will be trained, and procedures standardized using Work Instructions (WI) to prepare for the DRAGON 2 randomized controlled trial. Outcomes should reveal the accrual potential of centers, safety profile of combined PVE/HVE and the effect of FLR-hypertrophy induction by PVE/HVE in patients with CRLM and a small FLR.

TRIAL REGISTRATION

Clinicaltrials.gov: NCT04272931 (February 17, 2020). Toestingonline.nl: NL71535.068.19 (September 20, 2019).

The 3D-structure, kinetics and dynamics of the E. coli nitroreductase NfsA with NADP+ provide glimpses of its catalytic mechanism

Nitroreductases activate nitroaromatic antibiotics and cancer prodrugs to cytotoxic hydroxylamines and reduce quinones to quinols. Using steady-state and stopped-flow kinetics, we show that the Escherichia coli nitroreductase NfsA is 20-50 fold more active with NADPH than with NADH and that product release may be rate-limiting. The crystal structure of NfsA with NADP⁺ shows that a mobile loop forms a phosphate-binding pocket. The nicotinamide ring and nicotinamide ribose are mobile, as confirmed in molecular dynamics (MD) simulations. We present a model of NADPH bound to NfsA. Only one NADP⁺ is seen bound to the NfsA dimers, and MD simulations show that binding of a second NADP(H) cofactor is unfavourable, suggesting that NfsA and other members of this protein superfamily may have a half-of-sites mechanism.

O092 Fibrin-based haemostatic agents for reducing blood loss in adult liver resection: a meta-analysis

Introduction

Liver resection can be associated with significant perioperative bleeding. Fibrin based haemostatic agents (FBHAs) are bioabsorbable topical haemostatic agents used to enhance haemostasis and reduce blood loss. We performed a systematic review and meta-analysis, comparing FBHAs with the standard of care and no topical application (SoC), and comparing FBHAs with non-fibrin-based haemostatic agents (NFHAs) to evaluate their efficacy in reducing blood loss and improving perioperative outcomes.

Method

The Cochrane Hepato-Biliary Specialised Register was searched to identify (quasi-) RCTs to include in our meta-analysis. Two authors independently reviewed each study. Primary outcomes were haemostatic efficacy (defined as haemostasis within 4 or 5 minutes post application), adverse events and perioperative mortality (within 30-days of surgery). Statistical analyses were performed using the random effects model and results expressed as odds ratio (OR) with 95% confidence intervals.

Result

Twenty-seven RCTs (3736 participants) were included in our analysis. FBHAs were found to have superior haemostatic efficacy compared to NFHAs (OR 4.03; 1.73–9.36, p=0.001), and were superior to SoC (OR 13.59; 4.06–45.47, p<0.0001). Incidence of adverse events and perioperative mortality was no different when comparing FBHAs with SoC or NFHAs. No differences were detected when testing for post-operative bile leakage, intra-abdominal collections, volume of abdominal drain output, post-operative transfusion requirements, reoperation rates and length of stay (all p>0.05).

Conclusion

FBHAs appear superior to SoC and NFHAs in achieving haemostasis within 4–5 minutes post-application, however this does not translate into improved post-operative outcomes. FBHAs are not justified for routine use based on the available evidence.

O002 Diabetes-associated HLA donor genotypes and pancreas transplant outcomes

Introduction

The genotypes HLA DR3/DR4, DR3/DR3, DR4/DR4 are associated with a predisposition to diabetes. This study evaluated UK recipient outcomes after pancreas transplantation from donors with a diabetes-associated genotypes.

Methods

Data on all UK pancreas transplants from 2004–2019 was obtained from the NHSBT-UK Registry, n=2,938. HLA-DR type was recorded for all organ donors. Re-transplants and those missing patient (PS) or graft (GS) survival were excluded, resulting in a final cohort of n=2,661. We further delineated our categories into SPK, PTA and PAK as a previous study suggested different recipient categories may be adversely affected. Univariate analyses were conducted using Kaplan-Meier plots and multi-variate analysis using Cox-regression models. Complications were analysed using chi-squared analyses.

Results

The majority of grafts were from donors not associated with diabetes genotypes (90.1%, n=2397) whereas 5.4%(n=145) came from HLA DR3/DR4 donors, 1.6%(n=43) from DR3/DR3 and (n=76)2.9% from DR4/DR4. Comparable outcomes for GS at 1yr (SPK p=0.980, PTA p=0.759, PAK p=0.244) and 3yrs (SPK p=0.708, PTA p=0.744, PAK p=0.275) and PS at 1yr (SPK p=0.553, PTA p=0.527, PAK p=0.756) and 3yrs (SPK p=0.728, PTA p=0.928, PAK p=0.424) were seen. Multivariate analysis also showed no statistically significant difference in GS (p=0.604, HR 1.041, 95%CI 0.895, 1.211) or PS (p=0.623, HR 1.045, 95%CI 0.876, 1.248). There were comparable complication rates.

Conclusion

This multicentre UK study has found comparable survival outcomes and complication rates within our donor-HLA-genotype groups. We do not believe that the presence or absence of a diabetes associated HLA-genotype influences outcomes for any category of pancreas transplant.

Take-home message

We do not believe that the presence or absence of a diabetes-associated HLA-genotype influences outcomes for any category of pancreas transplant.

Location-Dependent Lanthanide Selectivity Engineered into Structurally Characterized Designed Coiled Coils

Herein we report unprecedented location-dependent, size-selective binding to designed lanthanide (Ln3+ ) sites within miniature protein coiled coil scaffolds. Not only do these engineered sites display unusual Ln3+ selectivity for moderately large Ln3+ ions (Nd to Tb), for the first time we demonstrate that selectivity can be location-dependent and can be programmed into the sequence. A 1 nm linear translation of the binding site towards the N-terminus can convert a selective site into a highly promiscuous one. An X-ray crystal structure, the first of a lanthanide binding site within a coiled coil to be reported, coupled with CD studies, reveal the existence of an optimal radius that likely stems from the structural constraints of the coiled coil scaffold. To the best of our knowledge this is the first report of location-dependent metal selectivity within a coiled coil scaffold, as well as the first report of location-dependent Ln3+ selectivity within a protein.

Cognitive Motor Dual Task Costs in Older Adults with Motoric Cognitive Risk Syndrome

The purpose of this study was to characterize Cognitive Motor Dual Task (CMDT) costs for a community-based sample of older adults with Motoric Cognitive Risk Syndrome (MCR), as well as investigate associations between CMDT costs and cognitive performance. Twenty-five community-dwelling older adults (ages 60-89 years) with MCR performed single and dual task complex walking scenarios, as well as a computerized cognitive testing battery. Participants with lower CMDT costs had higher scores on composite measures of Working Memory, Processing Speed, and Shifting, as well as an overall cognitive composite measure. In addition, participants with faster single task gait velocity had higher scores on composite measures of Working Memory, Processing Speed, and overall cognition. Taken together, these results suggest that CMDT paradigms can help to elucidate the interplay between cognitive and motor abilities for older adults with MCR.

O6: EARLY ANASTOMOTIC BILIARY COMPLICATIONS AFTER LIVER TRANSPLANTATION

Introduction

Biliary leaks and anastomotic strictures are common early biliary complications (EBC) following liver transplantation. However, their impact on outcomes remains controversial and poorly described.

Method

The NHS registry on adult liver transplantation between 2006 and 2017 was retrospectively reviewed (n=8304). Multiple imputations were performed to account for missing data. Adjusted regression models were used to assess predictors of EBC, and their impact on outcomes. 35 potential variables were included, and backwards stepwise selection enabled unbiased selection of variables for inclusion in final models.

Result

EBC occurred in 9.6% of patients. Adjusted cox regression revealed that EBCs have a significant and independent impact on graft survival (Leak HR=1.325; P=0.021, Stricture HR=1.514; P=0.002, Leak plus stricture HR=1.533; P=0.034) and patient survival (Leak HR=1.218; P=0.131, Stricture HR=1.578; P<0.001, Leak plus stricture HR=1.507; P=0.044). Patients with EBC had longer median hospital stay (23 versus 15 days; P<0.001) and increased chance for readmission within the first year (56% versus 32%; P<0.001). On adjusted logistic regression the following were identified as independent risk factors for development of EBC: donation following circulatory death (OR=1.280; P=0.009), accessory hepatic artery (OR=1.324; P=0.005), vascular anastomosis time in minutes (OR=1.005; P=0.032) and ethnicity ‘other’ (OR=1.838; P=0.011).

Conclusion

EBCs prolong hospital stay, increase readmission rates and are independent risk factors for diminished graft survival and increased mortality in liver transplantation. We have identified factors that increase the likelihood of EBC occurrence; further research into interventions to prevent EBCs in these at-risk groups is vital to improve liver transplantation outcomes.

Take-home message

Using a large registry database we have shown that early anastomotic biliary complications are independent risk factors for decreased graft survival and increased mortality after liver transplantation. Research into interventions to prevent biliary complications in high risk groups are essential to improve liver transplant outcomes.

Risk factors and impact of early anastomotic biliary complications after liver transplantation: UK registry analysis

Background

Biliary leaks and anastomotic strictures are common early anastomotic biliary complications (EABCs) following liver transplantation. However, there are no large multicentre studies investigating their clinical impact or risk factors. This study aimed to define the incidence, risk factors and impact of EABC.

Methods

The NHS registry on adult liver transplantation between 2006 and 2017 was reviewed retrospectively. Adjusted regression models were used to assess predictors of EABC, and their impact on outcomes.

Results

Analyses included 8304 liver transplant recipients. Patients with EABC (9·6 per cent) had prolonged hospitalization (23 versus 15 days; P < 0·001) and increased chance for readmission within the first year (56 versus 32 per cent; P < 0·001). Patients with EABC had decreased estimated 5-year graft survival of 75·1 versus 84·5 per cent in those without EABC, and decreased 5-year patient survival of 76·9 versus 83·3 per cent; both P < 0.001. Adjusted Cox regression revealed that EABCs have a significant and independent impact on graft survival (leak hazard ratio (HR) 1·344, P = 0·015; stricture HR 1·513, P = 0·002; leak plus stricture HR 1·526, P = 0·036) and patient survival (leak HR 1·215, P = 0·136, stricture HR 1·526, P = 0·001; leak plus stricture HR 1·509; P = 0·043). On adjusted logistic regression, risk factors for EABC included donation after circulatory death grafts, graft aberrant arterial anatomy, biliary anastomosis type, vascular anastomosis time and recipient model of end-stage liver disease.

Conclusion

EABCs prolong hospital stay, increase readmission rates and are independent risk factors for graft loss and increased mortality. This study has identified factors that increase the likelihood of EABC occurrence; research into interventions to prevent EABCs in these at-risk groups is vital to improve liver transplantation outcomes.

Robotic Versus Conventional Laparoscopic Liver Resections: A Systematic Review and Meta-Analysis

BACKGROUND

Theoretical advantages of robotic surgery compared to conventional laparoscopic surgery include improved instrument dexterity, 3D visualization, and better ergonomics. This systematic review and meta-analysis aimed to determine advantages of robotic surgery over laparoscopic surgery in patients undergoing liver resections.

METHOD

A systematic literature search was conducted for studies comparing robotic assisted or totally laparoscopic liver resection. Meta-analysis of intraoperative (operative time, blood loss, transfusion rate, conversion rate), oncological (R0 resection rates), and postoperative (bile leak, surgical site infection, pulmonary complications, 30-day and 90-day mortality, length of stay, 90-day readmission and reoperation rates) outcomes was performed using a random effects model.

RESULT

Twenty-six non-randomized studies including 2630 patients (950 robotic and 1680 laparoscopic) were included, of which 20% had major robotic liver resection and 14% had major laparoscopic liver resection. Intraoperatively, robotic liver resection was associated with significantly less blood loss (mean: 286 vs 301 mL, p < 0.001) but longer operating time (mean: 281 vs 221 min, p < 0.001). There were no significant differences in conversion rates or transfusion rates between robotic liver resection and laparoscopic liver resection. Postoperatively, there were no significant differences in overall complications, bile leaks, and length of hospital stay between robotic liver resection and laparoscopic liver resection. However, robotic liver resection was associated with significantly lower readmission rates than laparoscopic liver resection (odds ratio: 0.43, p = 0.005).

CONCLUSION

Robotic liver resection appears to offer some advantages compared to conventional laparoscopic surgery, although both techniques appear equivalent. Importantly, the quality of evidence is generally limited to cohort studies and a high-quality randomized trial comparing both techniques is needed.

Gemcitabine-based adjuvant chemotherapy in subtypes of ampullary adenocarcinoma: international propensity score-matched cohort study

BACKGROUND

Whether patients who undergo resection of ampullary adenocarcinoma have a survival benefit from adjuvant chemotherapy is currently unknown. The aim of this study was to compare survival between patients with and without adjuvant chemotherapy after resection of ampullary adenocarcinoma in a propensity score-matched analysis.

METHODS

An international multicentre cohort study was conducted, including patients who underwent pancreatoduodenectomy for ampullary adenocarcinoma between 2006 and 2017, in 13 centres in six countries. Propensity scores were used to match patients who received adjuvant chemotherapy with those who did not, in the entire cohort and in two subgroups (pancreatobiliary/mixed and intestinal subtypes). Survival was assessed using the Kaplan-Meier method and Cox regression analyses.

RESULTS

Overall, 1163 patients underwent pancreatoduodenectomy for ampullary adenocarcinoma. After excluding 187 patients, median survival in the remaining 976 patients was 67 (95 per cent c.i. 56 to 78) months. A total of 520 patients (53·3 per cent) received adjuvant chemotherapy. In a propensity score-matched cohort (194 patients in each group), survival was better among patients who received adjuvant chemotherapy than in those who did not (median survival not reached versus 60 months respectively; P = 0·051). A survival benefit was seen in patients with the pancreatobiliary/mixed subtype; median survival was not reached in patients receiving adjuvant chemotherapy and 32 months in the group without chemotherapy (P = 0·020). Patients with the intestinal subtype did not show any survival benefit from adjuvant chemotherapy.

CONCLUSION

Patients with resected ampullary adenocarcinoma may benefit from gemcitabine-based adjuvant chemotherapy, but this effect may be reserved for those with the pancreatobiliary and/or mixed subtype.

β-Cell and renal transplantation options for diabetes

Despite major advances in structured education, insulin delivery and glucose monitoring, diabetes self-management remains an unremitting challenge. Insulin therapy is inextricably linked to risk of dangerous hypoglycaemia and sustained hyperglycaemia remains a leading cause of renal failure. This review sets out to demystify transplantation for diabetes multidisciplinary teams, facilitating consideration and incorporation within holistic overall person-centred management. Deceased and living donor kidney, whole pancreas and isolated islet transplant procedures, indications and potential benefits are described, in addition to outcomes within the integrated UK transplant programme.

Prospective assessment of resection margin status following pancreaticoduodenectomy for pancreatic ductal adenocarcinoma after standardisation of margin definitions

BACKGROUND

Surgical resection remains the only curative treatment for pancreatic ductal adenocarcinoma (PDAC). The prognostic value of resection margin status following pancreatoduodenectomy (PD) remains controversial. Standardised pathological assessment increases positive margins but limited data is available on the significance of involved margins. We investigated the impact of resection margin status in PDAC on patient outcome.

METHOD

We identified all patients with PD for PDAC at one pancreatic cancer centre between August 2008 and December 2014. Demographic, operative, adjuvant therapeutic and survival data was obtained. Pathology data including resection margin status of specific anatomic margins was collected and analysed.

RESULTS

107 patients were included, all pathologically staged as T3 with 102 N1. 87.9% of patients were R1 of which 53.3% showed direct extension to the resection margin. Median survival for R0 patients versus R1<1 mm and R1 = 0 mm was 28.4 versus 15.4 and 25.1 versus 13.4 months. R1 = 0 mm status remained a predictor of poor outcome on multivariate analysis. Evaluation of individual margins (R1<1 mm) showed the SMV and SMA margins were associated with poorer overall survival. Multiple involved margins impacted negatively on outcome. SMA margin patient outcome with R1 = 1-1.9 mm was similar to R1=>2 mm.

CONCLUSION

Using an R1 definition of <1 mm and standardised pathology we demonstrate that R1 rates in PDAC can approach 90%. R1 = 0 mm remained an independent prognostic factor for overall survival. Using R1<1 mm we have shown that involvement of medial margins and multiple margins has significant negative impact on overall survival. We conclude that not all margin positivity has the same prognostic significance.

NUTRITIONAL RISK STATUS, DIETARY INTAKE AND COGNITIVE PERFORMANCE IN OLDER ADULTS WITH MOTORIC COGNITIVE RISK SYNDROME

Background

Modifiable lifestyle factors such as diet are associated with cognitive decline and dementia. Greater understanding of the nutritional intake of older adults who are at increased risk for cognitive decline may allow for the development of more effective dietary interventions to prevent or delay the onset of dementia.

Objectives

The purpose of this study was to characterize the nutritional status, diet quality and individual nutritional components of older adults with motoric cognitive risk syndrome (MCR). MCR is a pre-dementia syndrome classified by slow gait speed and subjective memory impairments.

Design

Cross-sectional analysis.

Setting

A community-based senior center located in an urban setting.

Participants

Twenty-five community-dwelling older adults with MCR aged 60-89 yrs.

Measurements

Nutritional risk status was determined using the Nestle Mini Nutritional Assessment (MNA). A food frequency questionnaire was used to quantify: overall dietary quality using the Healthy Eating Index (HEI); adherence to the Mediterranean-DASH for Neurodegenerative Delay (MIND) dietary pattern; and intake of individual nutritional components shown to be protective or harmful for cognitive function in older adults. Participants completed a computerized cognitive testing battery to assess cognitive abilities.

Results

More than one third (36%) of participants were at increased risk for malnutrition. Participants at lower risk for malnutrition had better working memory (r = 0.40, p = 0.04), executive functioning (r = 0.44, p = 0.03), and overall cognition (r = 0.44, p = 0.03). While participants generally consumed a reasonable quality diet (HEI = 65.15), 48% of participants had poor adherence to a neuroprotective MIND dietary pattern. Higher intake of B-complex vitamins was associated with better task switching (r = 0.40, p ≤ 0.05) and faster processing speeds (r = 0.39, p ≤ 0.05). Higher vitamin C intake was associated with better executive functioning (r = 0.40, p ≤ 0.05).

Conclusions

Our findings suggest that a significant proportion of older adults with MCR may be at increased risk for malnutrition. While the diet quality of older adults with MCR appeared to need improvement, future studies should investigate the effects of more specific nutritional interventions, including the MIND diet, on cognition in at-risk older adults.

A New Optical Remote Sensing Technique for High-Resolution Mapping of Soil Moisture

The recently developed OPtical TRApezoid Model (OPTRAM) has been successfully applied for watershed scale soil moisture (SM) estimation based on remotely sensed shortwave infrared (SWIR) transformed reflectance (TR_SWIR) and the normalized difference vegetation index (NDVI). This study is aimed at the evaluation of OPTRAM for field scale precision agriculture applications using ultrahigh spatial resolution optical observations obtained with one of the world's largest field robotic phenotyping scanners located in Maricopa, Arizona. We replaced NDVI with the soil adjusted vegetation index (SAVI), which has been shown to be more accurate for cropped agricultural fields that transition from bare soil to dense vegetation cover. The OPTRAM was parameterized based on the trapezoidal geometry of the pixel distribution within the TR_SWIR-SAVI space, from which wet- and dry-edge parameters were determined. The accuracy of the resultant SM estimates is evaluated based on a comparison with ground reference measurements obtained with Time Domain Reflectometry (TDR) sensors deployed to monitor surface, near-surface and root zone SM. The obtained results indicate an SM estimation error between 0.045 and 0.057 cm³ cm⁻³ for the near-surface and root zone, respectively. The high resolution SM maps clearly capture the spatial SM variability at the sensor locations. These findings and the presented framework can be applied in conjunction with Unmanned Aerial System (UAS) observations to assist with farm scale precision irrigation management to improve water use efficiency of cropping systems and conserve water in water-limited regions of the world.

Multicentre observational cohort study of implementation and outcomes of laparoscopic distal pancreatectomy

BACKGROUND

Laparoscopic distal pancreatectomy (LDP) is increasingly being performed as an alternative to open surgery. Whether the implementation and corresponding learning curve of LDP have an impact on patient outcome is unknown. The aim was to investigate the temporal trends in practice across UK centres.

METHODS

This was a retrospective multicentre observational cohort study of LDP in 11 tertiary referral centres in the UK between 2006 and 2016. The learning curve was analysed by pooling data for the first 15 consecutive patients who had LDP and examining trends in surgical outcomes in subsequent patients.

RESULTS

In total, 570 patients underwent LDP, whereas 888 underwent open resection. For LDP the median duration of operation was 240 min, with 200 ml blood loss. The conversion rate was 12·1 per cent. Neuroendocrine tumours (26·7 per cent) and mucinous cystic neoplasms (19·7 per cent) were commonest indications. The proportion of LDPs increased from 24·4 per cent in 2006-2009 (P1) to 46·0 per cent in 2014-2016 (P3) (P < 0·001). LDP was increasingly performed for patients aged 70 years or more (16 per cent in P1 versus 34·4 per cent in P3; P = 0·002), pancreatic ductal adenocarcinoma (6 versus 19·1 per cent; P = 0·005) and advanced malignant tumours (27 versus 52 per cent; P = 0·016). With increasing experience, there was a trend for a decrease in blood transfusion rate (14·1 per cent for procedures 1-15 to 3·5 per cent for procedures 46-75; P = 0·008), ICU admissions (32·7 to 19·2 per cent; P = 0·021) and median duration of hospital stay (7 (i.q.r. 5-9) to 6 (4-7) days; P = 0·002). After 30 procedures, a decrease was noted in rates of both overall morbidity (57·7 versus 42·2 per cent for procedures 16-30 versus 46-75 respectively; P = 0·009) and severe morbidity (18·8 versus 9·7 per cent; P = 0·031).

CONCLUSION

LDP has increased as a treatment option for lesions of the distal pancreas as indications for the procedure have expanded. Perioperative outcomes improved with the number of procedures performed.

The C-terminal tail of the bacterial translocation ATPase SecA modulates its activity

In bacteria, the translocation of proteins across the cytoplasmic membrane by the Sec machinery requires the ATPase SecA. SecA binds ribosomes and recognises nascent substrate proteins, but the molecular mechanism of nascent substrate recognition is unknown. We investigated the role of the C-terminal tail (CTT) of SecA in nascent polypeptide recognition. The CTT consists of a flexible linker (FLD) and a small metal-binding domain (MBD). Phylogenetic analysis and ribosome binding experiments indicated that the MBD interacts with 70S ribosomes. Disruption of the MBD only or the entire CTT had opposing effects on ribosome binding, substrate-protein binding, ATPase activity and in vivo function, suggesting that the CTT influences the conformation of SecA. Site-specific crosslinking indicated that F399 in SecA contacts ribosomal protein uL29, and binding to nascent chains disrupts this interaction. Structural studies provided insight into the CTT-mediated conformational changes in SecA. Our results suggest a mechanism for nascent substrate protein recognition.

Soil Microbiome Dynamics During Pyritic Mine Tailing Phytostabilization: Understanding Microbial Bioindicators of Soil Acidification

Challenges to the reclamation of pyritic mine tailings arise from in situ acid generation that severely constrains the growth of natural revegetation. While acid mine drainage (AMD) microbial communities are well-studied under highly acidic conditions, fewer studies document the dynamics of microbial communities that generate acid from pyritic material under less acidic conditions that can allow establishment and support of plant growth. This research characterizes the taxonomic composition dynamics of microbial communities present during a 6-year compost-assisted phytostabilization field study in extremely acidic pyritic mine tailings. A complementary microcosm experiment was performed to identify successional community populations that enable the acidification process across a pH gradient. Taxonomic profiles of the microbial populations in both the field study and microcosms reveal shifts in microbial communities that play pivotal roles in facilitating acidification during the transition between moderately and highly acidic conditions. The potential co-occurrence of organoheterotrophic and lithoautotrophic energy metabolisms during acid generation suggests the importance of both groups in facilitating acidification. Taken together, this research suggests that key microbial populations associated with pH transitions could be used as bioindicators for either sustained future plant growth or for acid generation conditions that inhibit further plant growth.

Phytoremediation Reduces Dust Emissions from Metal(loid)-Contaminated Mine Tailings

Environmental and health risk concerns relating to airborne particles from mining operations have focused primarily on smelting activities. However, there are only three active copper smelters and less than a dozen smelters for other metals compared to an estimated 500000 abandoned and unreclaimed hard rock mine tailings in the US that have the potential to generate dust. The problem can also extend to modern tailings impoundments, which may take decades to build and remain barren for the duration before subsequent reclamation. We examined the impact of vegetation cover and irrigation on dust emissions and metal(loid) transport from mine tailings during a phytoremediation field trial at the Iron King Mine and Humboldt Smelter Superfund (IKMHSS) site. Measurements of horizontal dust flux following phytoremediation reveals that vegetated plots with 16% and 32% canopy cover enabled an average dust deposition of 371.7 and 606.1 g m^-2 y^-1, respectively, in comparison to the control treatment which emitted dust at an average rate of 2323 g m^-2 y^-1. Horizontal dust flux and dust emissions from the vegetated field plots are comparable to emission rates in undisturbed grasslands. Further, phytoremediation was effective at reducing the concentration of fine particulates, including PM₁, PM_2.5, and PM₄, which represent the airborne particulates with the greatest health risks and the greatest potential for long-distance transport. This study demonstrates that phytoremediation can substantially decrease dust emissions as well as the transport of windblown contaminants from mine tailings.

Intrinsic disorder in the partitioning protein KorB persists after co-operative complex formation with operator DNA and KorA

The ParB protein, KorB, from the RK2 plasmid is required for DNA partitioning and transcriptional repression. It acts co-operatively with other proteins, including the repressor KorA. Like many multifunctional proteins, KorB contains regions of intrinsically disordered structure, existing in a large ensemble of interconverting conformations. Using NMR spectroscopy, circular dichroism and small-angle neutron scattering, we studied KorB selectively within its binary complexes with KorA and DNA, and within the ternary KorA/KorB/DNA complex. The bound KorB protein remains disordered with a mobile C-terminal domain and no changes in the secondary structure, but increases in the radius of gyration on complex formation. Comparison of wild-type KorB with an N-terminal deletion mutant allows a model of the ensemble average distances between the domains when bound to DNA. We propose that the positive co-operativity between KorB, KorA and DNA results from conformational restriction of KorB on binding each partner, while maintaining disorder.

Identification of Phosphorylation Sites Altering Pollen Soluble Inorganic Pyrophosphatase Activity

Protein phosphorylation regulates numerous cellular processes. Identifying the substrates and protein kinases involved is vital to understand how these important posttranslational modifications modulate biological function in eukaryotic cells. Pyrophosphatases catalyze the hydrolysis of inorganic phosphate (PP_i) to inorganic phosphate P_i, driving biosynthetic reactions; they are essential for low cytosolic inorganic phosphate. It was suggested recently that posttranslational regulation of Family I soluble inorganic pyrophosphatases (sPPases) may affect their activity. We previously demonstrated that two pollen-expressed sPPases, Pr-p26.1a and Pr-p26.1b, from the flowering plant Papaver rhoeas were inhibited by phosphorylation. Despite the potential significance, there is a paucity of data on sPPase phosphorylation and regulation. Here, we used liquid chromatographic tandem mass spectrometry to map phosphorylation sites to the otherwise divergent amino-terminal extensions on these pollen sPPases. Despite the absence of reports in the literature on mapping phosphorylation sites on sPPases, a database survey of various proteomes identified a number of examples, suggesting that phosphorylation may be a more widely used mechanism to regulate these enzymes. Phosphomimetic mutants of Pr-p26.1a/b significantly and differentially reduced PPase activities by up to 2.5-fold at pH 6.8 and 52% in the presence of Ca²⁺ and hydrogen peroxide over unmodified proteins. This indicates that phosphoregulation of key sites can inhibit the catalytic responsiveness of these proteins in concert with key intracellular events. As sPPases are essential for many metabolic pathways in eukaryotic cells, our findings identify the phosphorylation of sPPases as a potential master regulatory mechanism that could be used to attenuate metabolism.

Erratum: Title of article: Why more mothers die - Confidential enquiries into institutional maternal deaths in the Southern Region of Malawi, 2001

[This corrects the article on p. 73 in vol. 17.].

Phytostabilization of mine tailings using compost-assisted direct planting: Translating greenhouse results to the field

Standard practice in reclamation of mine tailings is the emplacement of a 15 to 90cm soil/gravel/rock cap which is then hydro-seeded. In this study we investigate compost-assisted direct planting phytostabilization technology as an alternative to standard cap and plant practices. In phytostabilization the goal is to establish a vegetative cap using native plants that stabilize metals in the root zone with little to no shoot accumulation. The study site is a barren 62-hectare tailings pile characterized by extremely acidic pH as well as lead, arsenic, and zinc each exceeding 2000mgkg(-1). The study objective is to evaluate whether successful greenhouse phytostabilization results are scalable to the field. In May 2010, a 0.27ha study area was established on the Iron King Mine and Humboldt Smelter Superfund (IKMHSS) site with six irrigated treatments; tailings amended with 10, 15, or 20% (w/w) compost seeded with a mix of native plants (buffalo grass, arizona fescue, quailbush, mountain mahogany, mesquite, and catclaw acacia) and controls including composted (15 and 20%) unseeded treatments and an uncomposted unseeded treatment. Canopy cover ranging from 21 to 61% developed after 41 months in the compost-amended planted treatments, a canopy cover similar to that found in the surrounding region. No plants grew on unamended tailings. Neutrophilic heterotrophic bacterial counts were 1.5 to 4 orders of magnitude higher after 41months in planted versus unamended control plots. Shoot tissue accumulation of various metal(loids) was at or below Domestic Animal Toxicity Limits, with some plant specific exceptions in treatments receiving less compost. Parameters including % canopy cover, neutrophilic heterotrophic bacteria counts, and shoot uptake of metal(loids) are promising criteria to use in evaluating reclamation success. In summary, compost amendment and seeding, guided by preliminary greenhouse studies, allowed plant establishment and sustained growth over 4years demonstrating feasibility for this phytostabilization technology.

Flexibility of KorA, a plasmid-encoded, global transcription regulator, in the presence and the absence of its operator

The IncP (Incompatibility group P) plasmids are important carriers in the spread of antibiotic resistance across Gram-negative bacteria. Gene expression in the IncP-1 plasmids is stringently controlled by a network of four global repressors, KorA, KorB, TrbA and KorC interacting cooperatively. Intriguingly, KorA and KorB can act as co-repressors at varying distances between their operators, even when they are moved to be on opposite sides of the DNA. KorA is a homodimer with the 101-amino acid subunits, folding into an N-terminal DNA-binding domain and a C-terminal dimerization domain. In this study, we have determined the structures of the free KorA repressor and two complexes each bound to a 20-bp palindromic DNA duplex containing its consensus operator sequence. Using a combination of X-ray crystallography, nuclear magnetic resonance spectroscopy, SAXS and molecular dynamics calculations, we show that the linker between the two domains is very flexible and the protein remains highly mobile in the presence of DNA. This flexibility allows the DNA-binding domains of the dimer to straddle the operator DNA on binding and is likely to be important in cooperative binding to KorB. Unexpectedly, the C-terminal domain of KorA is structurally similar to the dimerization domain of the tumour suppressor p53.

Mice with Dab1 or Vldlr insufficiency exhibit abnormal neonatal vocalization patterns

Genetic and epigenetic changes in components of the Reelin-signaling pathway (RELN, DAB1) are associated with autism spectrum disorder (ASD) risk. Social communication deficits are a key component of the ASD diagnostic criteria, but the underlying neurogenetic mechanisms remain unknown. Reln insufficient mice exhibit ASD-like behavioral phenotypes including altered neonatal vocalization patterns. Reelin affects multiple pathways including through the receptors, Very low-density lipoprotein receptor (Vldlr), Apolipoprotein receptor 2 (Apoer2), and intracellular signaling molecule Disabled-1 (Dab1). As Vldlr was previously implicated in avian vocalization, here we investigate vocalizations of neonatal mice with a reduction or absence of these components of the Reelin-signaling pathway. Mice with low or no Dab1 expression exhibited reduced calling rates, altered call-type usage, and differential vocal development trajectories. Mice lacking Vldlr expression also had altered call repertoires, and this effect was exacerbated by deficiency in Apoer2. Together with previous findings, these observations 1) solidify a role for Reelin in vocal communication of multiple species, 2) point to the canonical Reelin-signaling pathway as critical for development of normal neonatal calling patterns in mice, and 3) suggest that mutants in this pathway could be used as murine models for Reelin-associated vocal deficits in humans.

A conserved asparagine makes an essential contact to an RNA adenosine or cytidine

Abstract Post-transriptional regulation of yeast ribosomal protein L30, RPL30, requires the formation of a complex comprised of RPL30 and its RNA transcript [J. Vilardell and J. R. Warner, Genes & Dev. 8, 211-220 (1994)]. Mutational analysis of both the RNA and the protein reveals that an asparagine-adenosine contact is important. Replacement of the asparagine by alanine weakens binding dramatically, but substitution of the adenosine by cytidine or guanosine slightly increases or decreases respective binding affinities for RPL30. The structure of the complex has been solved by NMR and shows a conserved asparagine in position to form two hydrogen bonds with adenosine's Watson-Crick face [H. Mao, S. A. White and J. R. Williamson, Nat. Struct. Biol. 6, 1139-1147 (1999)]. Asparagine is necessary for this interaction but relatively small differences in binding affinity are measured for three different nucleotides.

De Novo Donor-Specific HLA Antibodies Are Associated With Rapid Loss of Graft Function Following Islet Transplantation in Type 1 Diabetes

Outcomes after islet transplantation continue to improve but etiology of graft failure remains unclear. De novo donor-specific human leukocyte antigen (HLA) antibodies (DSA) posttransplant are increasingly recognized as a negative prognostic marker. Specific temporal associations between DSA and graft function remain undefined particularly in programs undertaking multiple sequential transplants. Impact of de novo DSA on graft function over 12 months following first islet transplant was determined prospectively in consecutive recipients taking tacrolimus/mycophenolate immunosuppression at a single center. Mixed-meal tolerance test was undertaken in parallel with HLA antibody assessment pretransplant and 1-3 months posttransplant. Sixteen participants received a total of 26 islet transplants. Five (19%) grafts were associated with de novo DSA. Five (31%) recipients were affected: three post-first transplant; two post-second transplant. DSA developed within 4 weeks of all sensitizing grafts and were associated with decreased stimulated C-peptide (median [interquartile range]) at 3 months posttransplant (DSA negative: 613(300-1090); DSA positive 106(34-235) pmol/L [p = 0.004]). De novo DSA directed against most recent islet transplant were absolutely associated with loss of graft function despite maintained immunosuppression at 12 months in the absence of a rescue nonsensitizing transplant. Alemtuzumab induction immunosuppression was associated with reduced incidence of de novo DSA formation (p = 0.03).

Port site metastases following laparoscopic liver resection for hepatocellular carcinoma

A laparoscopic approach is being used increasingly in specialist centres for the resection of hepatocellular carcinomas and compares favourably with the traditional open approach, in terms of perioperative morbidity and mortality as well as long-term survival. We present a case of port site recurrence in a patient who underwent a laparoscopic left lateral segmentectomy for a hepatocellular carcinoma diagnosed during investigation of symptomatic gallstones. Nearly three years following surgery, surveillance computed tomography demonstrated a suspicious lesion at the site of one of the laparoscopic ports. Further resection was carried out and the lesion was confirmed histologically to be an isolated recurrence of the primary hepatocellular carcinoma, involving peritoneum and adominal wall. This case demonstrates that it is possible to encounter port site metastasis following laparoscopic resection of primary liver tumours although the incidence is very rare.

Selective internal radiation therapy for liver malignancies

BACKGROUND

Selective internal radiation therapy (SIRT) is a non-ablative technique for the treatment of liver primaries and metastases, with the intention of reducing tumour bulk. This study aimed to determine optimal patient selection, and elucidate its role as a downsizing modality.

METHODS

Data were collected retrospectively on patients who underwent SIRT between 2011 and 2014. The procedure was performed percutaneously by an expert radiologist. Response was analysed in two categories, based on radiological (CT/MRI according to Response Evaluation Criteria In Solid Tumours (RECIST)) and biological (α-fetoprotein, carcinoembryonic antigen, carbohydrate antigen 19-9, chromogranin A) parameters.

RESULTS

Forty-four patients were included. Liver metastases from colorectal cancer (22 patients) and hepatocellular carcinoma (HCC) (9) were the most common pathologies. Radiological response data were collected from 31 patients. A reduction in sum of diameters (SOD) was observed in patients with HCC (median -24.1 (95 per cent c.i. -43.4 to -3.8) per cent) and neuroendocrine tumours (-30.0 (-45.6 to -7.7) per cent), whereas a slight increase in SOD was seen in patients with colorectal cancer (4.9 (-10.6 to 55.3) per cent). Biological response was assessed in 17 patients, with a reduction in 12, a mixed response in two and no improvement in three. Six- and 12-month overall survival rates were 71 and 41 per cent respectively. There was no difference in overall survival between the RECIST response groups (median survival 375, 290 and 214 days for patients with a partial response, stable disease and progressive disease respectively; P = 0.130), or according to primary pathology (P = 0.063). Seven patients underwent liver resection with variable responses after SIRT.

CONCLUSION

SIRT may be used to downsize tumours and may be used as a bridge to surgery in patients with tumours deemed borderline for resection.

Implications of the index cholecystectomy and timing of referral for radical resection of advanced incidental gallbladder cancer

INTRODUCTION

Advanced (pT2/T3) incidental gallbladder cancer is often deemed unresectable after restaging. This study assesses the impact of the primary operation, tumour characteristics and timing of management on re-resection.

METHODS

The records of 60 consecutive referrals for incidental gallbladder cancer in a single tertiary centre from 2003 to 2011 were reviewed retrospectively. Decision on re-resection of incidental gallbladder cancer was based on delayed interval restaging at three months following cholecystectomy. Demographics, index cholecystectomy data, primary pathology, CA19-9 tumour marker levels at referral and time from cholecystectomy to referral as well as from referral to restaging were analysed.

RESULTS

Thirty-seven patients with pT2 and twelve patients with pT3 incidental gallbladder cancer were candidates for radical re-resection. Following interval restaging, 24 patients (49%) underwent radical resection and 25 (51%) were deemed inoperable. The inoperable group had significantly more patients with positive resection margins at cholecystectomy (p=0.002), significantly higher median CA19-9 levels at referral (p=0.018) and were referred significantly earlier (p=0.004) than the patients who had resectable tumours. On multivariate analysis, urgent referral (p=0.036) and incomplete cholecystectomy (p=0.048) were associated significantly with inoperable disease following restaging.

CONCLUSIONS

In patients with incidental, potentially resectable, pT2/T3 gallbladder cancer, inappropriate index cholecystectomy may have a significant impact on tumour dissemination. Early referral of breached tumours is not associated with resectability.

Oncological feasibility of laparoscopic distal pancreatectomy for adenocarcinoma: a single-institution comparative study

BACKGROUND

Laparoscopic distal pancreatectomy (LDP) is performed increasingly for pancreatic pathology in the body and tail of the pancreas. However, only few reports have compared its oncological efficacy with open distal pancreatectomy (ODP). We compared these two techniques in patients with pancreatic ductal adenocarcinoma.

METHODS

From a prospectively maintained database, all patients who underwent either LDP or ODP for adenocarcinoma in the body and tail of the pancreas between January 2008 and December 2011 were compared. Data were analysed using SPSS(®) v19 utilising standard tests. A p value <0.05 was considered significant.

RESULTS

Of 101 patients who underwent distal pancreatectomy, 22 had histologically confirmed adenocarcinoma (LDP n = 8, ODP n = 14). Both groups were well matched for age and the size of tumour (22 vs. 32 mm, p = 0.22). Intraoperative blood loss was 306 ml compared with 650 ml for ODP (p = 0.152). A longer operative time was noted for LDP (376 vs. 274 min, p < 0.05). Total length of stay was shorter for LDP compared with ODP (8 vs. 12 days, p = 0.05). The number of postoperative pancreatic fistulas were similar (LDP n = 2 vs. ODP n = 3, p = 0.5). Complete resection (R0) was achieved in 88 % of LDP (n = 7) compared with 86 % of ODP (n = 12). The median number of lymph nodes harvested was 16 for LDP versus 14 for ODP. Overall 3-year survival also was similar: LDP = 82 %, ODP = 74 % (p = 0.89).

CONCLUSIONS

From an oncological perspective, LDP is a viable procedure and its results are comparable to ODP for ductal adenocarcinomas arising in the body and tail of the pancreas.

Systematic review of irreversible electroporation in the treatment of advanced pancreatic cancer

BACKGROUND

Irreversible electroporation (IRE) is a novel procedure to combat pancreatic cancer, whereby high voltage pulses are delivered, resulting in cell death. This represents an ideal alternative to other thermal treatment modalities, as there is no overriding heat effect, therefore reducing the risk of injury to vessels and ducts.

METHODS

Multiple databases were searched to January 2014. Primary outcome measures were survival and associated morbidity. 41 articles were initially identified; of these 4 studies met the inclusion criteria, yielding 74 patients in total.

RESULTS

94.5% of patients had locally advanced tumours, the remainder had metastatic disease. Treated tumour size ranged from 1 to 7 cm. IRE approach included open (70.3%), laparoscopic (2.7%) and percutaneous (27%; ultrasound-guided 30%, CT-guided 70%) Morbidity ranged from 0 to 33%; due to the high number of simultaneous procedures performed (resection/bypass) it was difficult to ascertain IRE-related complications. However no significant bleeding occurred when IRE-alone was performed. Survival statistics suggest a prognostic benefit. Reported survival included: 6 month survival of 40% (n = 5) and 70% (n = 14); PFS and OS 14 and 20 months respectively (n = 54). Results of most interest showed a significant survival benefit in matched IRE vs non-IRE groups (PFS 14 vs 6 mths; p = 0.01, OS 20 vs 11 mths; p = 0.03).

CONCLUSION

Initial evidence suggests IRE incurs a prognostic benefit with minimal morbidity. More high quality research is required to determine the role IRE may play in the multi-modal management of pancreatic cancers.

Validation of the haemoglobin colour scale for screening blood donors in Malawi

BACKGROUND

In 2009 Malawi introduced a new protocol to screen potential blood donors for anaemia, using the WHO Haemoglobin Colour Scale (HCS) for initial screening. Published studies of the accuracy of the HCS to screen potential blood donors show varying levels of accuracy and opinion varies whether this is an appropriate screening test. The aim of the study was to assess the validity of the HCS, as a screening test, by comparison to HemoCue in potential blood donors in Malawi.

STUDY DESIGN AND METHODS

This was a blinded prospective study in potential blood donors aged over 18 years, at Malawi Blood Transfusion Service in Blantyre, Malawi. Capillary blood samples were analysed using the HCS and HemoCue, independent of each other. The sensitivity and specificity of correctly identifying ineligible blood donors (Hb ≤ 12 g/dL) were calculated.

RESULTS

From 242 participants 234 (96.7%) were correctly allocated and 8 (3.3%), were wrongly allocated on the basis of the Haemoglobin Colour Scale (HCS) compared to HemoCue, all were subjects that were wrongly accepted as donors when their haemoglobin results were ≤ 12.0 g/dL. This gave a sensitivity of 100% and specificity of 96.7% to detect donor eligibilty. The negative predictive value of the HCS was 100% but the positive predictive value to identify ineligible donors on the basis of anaemia was only 20%.

CONCLUSIONS

Initial screening with the HCS correctly predicts eligibility for blood donation in the majority of potential blood donors at considerable cost saving compared with use of HemoCue as the first line anaemia screening test, however, by this method a small number of anaemic patients were allowed to donate blood.

In Situ Production of Zoospores by Five Species of Phytophthora in Aqueous Environments for Use as Inocula

The goal of this study was to develop a procedure that could be used to evaluate the potential susceptibility of aquatic plants used in constructed wetlands to species of Phytophthora commonly found in nurseries. V8 agar plugs from actively growing cultures of three or four isolates of Phytophthora cinnamomi, P. citrophthora, P. cryptogea, P. nicotianae, and P. palmivora were used to produce inocula. In a laboratory experiment, plugs were placed in plastic cups and covered with 1.5% nonsterile soil extract solution (SES) for 29 days, and zoospore presence and activity in the solution were monitored at 2- or 3-day intervals with a rhododendron leaf disk baiting bioassay. In a greenhouse experiment, plugs of each species of Phytophthora were placed in plastic pots and covered with either SES or Milli-Q water for 13 days during both summer and winter months, and zoospore presence in the solutions were monitored at 3-day intervals with the baiting bioassay and by filtration. Zoospores were present in solutions throughout the 29-day and 13-day experimental periods but consistency of zoospore release varied by species. In the laboratory experiment, colonization of leaf baits decreased over time for some species and often varied among isolates within a species. In the greenhouse experiment, bait colonization decreased over time in both summer and winter, varied among species of Phytophthora in the winter, and was better in Milli-Q water. Zoospore densities in solutions were greater in the summer than in the winter. Decreased zoospore activities for some species of Phytophthora were associated with prolonged temperatures below 13 or above 30°C in the greenhouse. Zoospores from plugs were released consistently in aqueous solutions for at least 13 days. This procedure can be used to provide in situ inocula for the five species of Phytophthora used in this study so that aquatic plant species can be evaluated for potential susceptibility.

Methods of haemostasis during liver resection--a UK national survey

BACKGROUND

Although haemorrhage is a major cause of morbidity and mortality in liver surgery, there is very little available guidance on its management.

METHODS

The aim of this study was to identify current practice in the UK in this regard. An online survey was created and hepatobiliary (HPB) specialists who were members of a specialist society and others who were known practitioners were invited by e-mail to complete the survey anonymously.

RESULTS

Fifty-one percent responded (n = 36/70), and most of these respondents worked at large HPB centres (>100 liver resections/year; n = 24, 66%). Not all questionnaires were fully completed by the individual surgeons. Thirty-eight percent of the surgeons routinely used Pringle's manoeuvre. Most surgeons used ligation of the inflow vessels (n = 16, 44%) and stapled the outflow vessels (n = 15, 42%). The Cavitron ultrasonic surgical aspirator (CUSA; 54%, 13/24) was preferred for parenchymal transection. The majority routinely used haemostatic adjuncts (n = 22, 62%), whilst 33% (n = 12) used them occasionally. Twenty-three (64%) felt manufactured haemostatic adjuncts played a major role in maintaining haemostasis and 19 preferred fibrin-based products.

CONCLUSION

The Pringle manoeuvre is a popular technique amongst specialist UK liver surgeons and the CUSA is used by nearly half of the surgeons. Despite the absence of definitive evidence for their benefit, manufactured haemostatic adjuncts are still widely used, especially the fibrin-based adjuncts.

Prognostic factors and survival after resection of colorectal liver metastasis in the era of preoperative chemotherapy: an 11-year single-centre study

INTRODUCTION

A variety of factors have been identified in the literature which influence survival following resection of colorectal liver metastases (CRLM). Much of this literature is historical, and its relevance to contemporary practice is not known. The aim of this study was to identify those factors which influence survival during the era of preoperative chemotherapy in patients undergoing resection of CRLM in a UK centre.

METHODS

All patients having liver resection for CRLM during an 11-year period up to 2011 were identified from a prospectively maintained database. Prognostic factors analysed included tumour size (≥5 or <5 cm), lymph node status of the primary tumour, margin positivity (R1; <1 mm), neo-adjuvant chemotherapy (for liver), tumour differentiation, number of liver metastases (≥4), preoperative carcinoembryonic antigen (CEA; ≥200 ng/ml) and whether metastases were synchronous (i.e. diagnosed within 12 months of colorectal resection) or metachronous to the primary tumour. Overall survival (OS) was compared using Kaplan-Meier plots and a log rank test for significance. Multivariate analysis was performed using a Cox regression model. Statistical analysis was performed in SPSS v19, and p < 0.05 was considered to be significant.

RESULTS

432 patients underwent resection of CRLM during this period (67% male; mean age 64.5 years), and of these, 54 (13.5%) had re-resections. The overall 5-year survival in this series was 43% with an actuarial 10-year survival of 40%. A preoperative CEA ≥200 ng/ml was present in 10% of patients and was associated with a poorer 5-year OS (24 vs. 45%; p < 0.001). A positive resection margin <1 mm was present in 16% of patients, and this had a negative impact on 5-year OS (15 vs. 47%; p < 0.001). Tumour differentiation, number, biliary or vascular invasion, size, relationship to primary disease, nodal status of the primary disease or the use of neo-adjuvant chemotherapy had no impact on OS. Multivariate analysis identified only the presence of a positive resection margin (OR 1.75; p < 0.05) and a preoperative CEA ≥200 ng/ml (OR 1.88; p < 0.01) as independent predictors of poor OS.

CONCLUSION

Despite the wide variety of prognostic factors reported in the literature, this study was only able to identify a preoperative CEA ≥200 ng/ml and the presence of tumour within 1 mm of the resection margin as being of value in predicting survival. These variables are likely to identify patients who may benefit from intensive follow-up to enable early aggressive treatment of recurrent disease.

Double bypass for inoperable pancreatic malignancy at laparotomy: postoperative complications and long-term outcome

INTRODUCTION

Between 4% and 13% of patients with operable pancreatic malignancy are found unresectable at the time of surgery. Double bypass is a good option for fit patients but it is associated with high risk of postoperative complications. The aim of this study was to identify pre-operatively which patients undergoing double bypass are at high risk of complications and to assess their long-term outcome.

METHODS

Of the 576 patients undergoing pancreatic resections between 2006 and 2011, 50 patients who underwent a laparotomy for a planned pancreaticoduodenectomy had a double bypass procedure for inoperable disease. Demographic data, risk factors for postoperative complications and pre-operative anaesthetic assessment data including the Portsmouth Physiological and Operative Severity Score for the enUmeration of Mortality and morbidity (P-POSSUM) and cardiopulmonary exercise testing (CPET) were collected.

RESULTS

Fifty patients (33 men and 17 women) were included in the study. The median patient age was 64 years (range: 39–79 years). The complication rate was 50% and the in-hospital mortality rate was 4%. The P-POSSUM physiology subscore and low anaerobic threshold at CPET were significantly associated with postoperative complications (p=0.005 and p=0.016 respectively) but they were unable to predict them. Overall long-term survival was significantly shorter in patients with postoperative complications (9 vs 18 months). Postoperative complications were independently associated with poorer long-term survival (p=0.003, odds ratio: 3.261).

CONCLUSIONS

P-POSSUM and CPET are associated with postoperative complications but the possibility of using them for risk prediction requires further research. However, postoperative complications following double bypass have a significant impact on long-term survival and this type of surgery should therefore only be performed in specialised centres.

Liver damage during organ donor procurement in donation after circulatory death compared with donation after brain death

Background

During the past decade the number of livers recovered and transplanted from donation after circulatory death (DCD) donors has increased significantly. As reported previously, injuries are more frequent during kidney procurement from DCD than from donation after brain death (DBD) donors. This aim of this study was to compare outcomes between DCD and DBD with respect to liver injuries.

Methods

Data on liver injuries in organs procured between 2000 and 2010 were obtained from the UK Transplant Registry.

Results

A total of 7146 livers were recovered from deceased donors during the study, 628 (8·8 per cent) from DCD donors. Injuries occurred in 1001 procedures (14·0 per cent). There were more arterial (1·6 versus 1·0 per cent), portal (0·5 versus 0·3 per cent) and caval (0·3 versus 0·2 per cent) injuries in the DBD group than in the DCD group, although none of these findings was statistically significant. Capsular injuries occurred more frequently in DCD than DBD (15·6 versus 11·4 per cent; P = 0·002). There was no significant difference between DCD and DBD groups in liver discard rates related to damage.

Conclusion

There were no differences in terms of vascular injuries between DCD and DBD livers, although capsular injuries occurred more frequently in DCD organs. Continuing the trend for increased frequency of DCD liver recovery, and ensuring that there is an adequately skilled surgical team available for procurement, is vital to improving the utilization of DCD livers.

Effects of low cardiopulmonary reserve on pancreatic leak following pancreaticoduodenectomy

Background

Postoperative complications are increased in patients with reduced cardiopulmonary reserve undergoing major surgery. Pancreatic leak is an important contributor to postoperative complications and death following pancreaticoduodenectomy. The aim of this study was to determine whether reduced cardiopulmonary reserve was a risk factor for pancreatic leak.

Methods

All patients who underwent pancreaticoduodenectomy between January 2006 and July 2010 were identified from a prospectively held database. Data analysis was restricted to those who underwent cardiopulmonary exercise testing during preoperative assessment. Pancreatic leak was defined as grade A, B or C according to the International Study Group on Pancreatic Fistula definition. An anaerobic threshold (AT) cut-off value of 10·1 ml per kg per min was used to identify patients with reduced cardiopulmonary reserve. Univariable and multivariable analyses were performed to identify other risk factors for pancreatic leak.

Results

Some 67 men and 57 women with a median age of 66 (range 37–82) years were identified. Low AT was significantly associated with pancreatic leak (45 versus 19·2 per cent in patients with greater cardiopulmonary reserve; P = 0·020), postoperative complications (70 versus 38·5 per cent; P = 0·013) and prolonged hospital stay (29·4 versus 17·5 days; P = 0·001). On multivariable analysis, an AT of 10·1 ml per kg per min or less was the only independent factor associated with pancreatic leak.

Conclusion

Low cardiopulmonary reserve was associated with pancreatic leak following pancreaticoduodenectomy. AT seems a useful tool for stratifying the risk of postoperative complications.

Kidney damage during organ recovery in donation after circulatory death donors: data from UK National Transplant Database

During the last 10 years, kidneys recovered/transplanted from donors after circulatory death (DCD) have significantly increased. To optimize their use, there has been an urgent need to minimize both warm and cold ischemia, which often necessitates more rapid removal. To compare the rates of kidney injury during procurement from DCD and donors after brain death (DBD) organ donors. A total of 13 260 kidney procurements were performed in the United Kingdom over a 10-year period (2000-2010). Injuries occurred in 903 procedures (7.1%). Twelve thousand three hundred seventy-two (93.3%) kidneys were recovered from DBD donors and 888 (6.7%) from DCD donors. The rates of kidney injury were significantly higher when recovered from DCD donors (11.4% vs. 6.8%, p < 0.001). Capsular, ureteric and vascular injuries were all significantly more frequent (p = 0.002, p < 0.001 and p = 0.017, respectively). Discard because of injury was more common after DCD donation (p = 0.002). Multivariate analysis demonstrated procurement injuries were significantly associated with DCD donors (p = 0.035) and increased donor age (<0.001) and donor body mass index (BMI; 0.001), donor male gender (p = 0.001) and no liver donation (0.009). We conclude that procurement from DCD donors leads to higher rates of injury to the kidney and are more likely to be discarded.

Metastatic lymph node ratio as an important prognostic factor in pancreatic ductal adenocarcinoma

BACKGROUND

Overall five year survival following pancreaticoduodenectomy for ductal adenocarcinoma is poor with typical reported rates in the literature of 8-27%. The aim of this study was to identify the histological variables best able to predict long-term survival in these patients.

METHODS

A prospective database of patients undergoing pancreaticoduodenectomy between April 2002 and June 2009 was analysed to identify patients with histologically proven pancreatic ductal adenocarcinoma. Patients with ampullary tumours, cholangiocarcinoma, duodenal adenocarcinoma and neuroendocrine tumours were excluded. The histology reports for these patients were reviewed. Uni-variate and multi-variate survival analysis was performed to identify variables useful in predicting long-term outcome.

RESULTS

134 patients underwent pancreaticoduodenectomy for pancreatic ductal adenocarcinoma during this period. 5 year survival in this series was 18.6%. Uni-variate analysis identified nodal status and the metastatic to resected lymph node ratio as predictors of survival. Using multi-variate Cox Regression analysis a metastatic to lymph node ratio of >15% (p < 0.01) and the presence of perineural invasion (p < 0.05) were identified as independent predictors of patient survival. Metastatic to resected lymph node ratio is better able to stratify prognosis than nodal status alone with 5 year survival of those with N0 disease being 55.6% and 12.9% for N1 disease. However for those with <15% of resected nodes positive, 5 year survival was 21.7% and in those with >15% nodes positive it was 5.2% (p = 0.0017).

CONCLUSION

The metastatic to resected lymph node ratio can provide significant prognostic information in those patients with node positive disease after pancreaticoduodenectomy for pancreatic ductal adenocarcinoma.

Intraoperative cholangiography in the laparoscopic cholecystectomy era: why are we still debating?

Laparoscopic cholecystectomy is now one of the most frequently performed abdominal surgical procedures in the world. The most common major complication is bile duct injury, which can have catastrophic repercussions for patients and it has been suggested that intraoperative cholangiography may reduce the rate of bile duct injury. Whether this procedure should be performed routinely is still an active subject of debate. We discuss the available evidence and likely implications for the future.

Response of key soil parameters during compost-assisted phytostabilization in extremely acidic tailings: effect of plant species

Phytostabilization of mine tailings acts to mitigate both eolian dispersion and water erosion events which can disseminate barren tailings over large distances. This technology uses plants to establish a vegetative cover to permanently immobilize contaminants in the rooting zone, often requiring addition of an amendment to assist plant growth. Here we report the results of a greenhouse study that evaluated the ability of six native plant species to grow in extremely acidic (pH ∼ 2.5) metalliferous (As, Pb, Zn: 2000-3000 mg kg(-1)) mine tailings from Iron King Mine Humboldt Smelter Superfund site when amended with a range of compost concentrations. Results revealed that three of the six plant species tested (buffalo grass, mesquite, and catclaw acacia) are good candidates for phytostabilization at an optimum level of 15% compost (w/w) amendment showing good growth and minimal shoot accumulation of metal(loid)s. A fourth candidate, quailbush, also met all criteria except for exceeding the domestic animal toxicity limit for shoot accumulation of zinc. A key finding of this study was that the plant species that grew most successfully on these tailings significantly influenced key tailings parameters; direct correlations between plant biomass and both increased tailings pH and neutrophilic heterotrophic bacterial counts were observed. We also observed decreased iron oxidizer counts and decreased bioavailability of metal(loid)s mainly as a result of compost amendment. Taken together, these results suggest that the phytostabilization process reduced tailings toxicity as well as the potential for metal(loid) mobilization. This study provides practical information on plant and tailings characteristics that is critically needed for successful implementation of assisted phytostabilization on acidic, metalliferous mine tailings sites.

The HPB Clinic: Do Patients Want a Copy of Their Clinic Letter?

The NHS plan published by the Department of Health (DH) in 2000 recommended that patients should receive copies of all clinician-generated correspondence written about them. Concerns from many groups delayed widespread implementation of the policy and a committee set up under the NHS Modernisation Board recommended that further research was required in this area prior to rolling out the policy fully. Good practice guidelines on copying letters to patients were subsequently produced by the DH in 2001.