Surviving in a semi-marine habitat: Dietary salt exposure and salt secretion of a New Zealand intertidal skink.

Species that inhabit marine and intertidal ecosystems face osmoregulatory challenges, risking dehydration and increased ion concentrations in the body. Lizards need to either tolerate or regulate these increased ion concentrations. In this study, we aim to understand how Suter's skink (Oligosoma suteri), an intertidal skink restricted to shoreline habitats, is able to cope with the physiological stress of living in an extreme salt environment. We determined the diet, prey species' salt content, and nasal and cloacal salt excretion on Rangitoto and Motutapu Islands in northern New Zealand, where the skinks have contrasting access to terrestrial invertebrates. Analysis of stable isotopes suggests inter- and intra-population variability in Suter's skink diets. Intertidal invertebrates under washed up seaweed appear to compose a major part of the diet of the Rangitoto population, while the Motutapu population showed evidence for a mixed diet of terrestrial and intertidal invertebrates. Sodium content of prey species decreased with an increasing distance from the seawater. Field secretion of cations through nasal glands consisted primarily of Na(+), which is consistent with other marine and intertidal species. Sodium was also the primary cation in urine. In contrast, fecal cations consisted primarily of K(+). This first study into the salt secretion of an intertidal skink species provides evidence of Suter's skink's plasticity in secreting excess ions through nasal salt glands. This likely enables it to deal with the challenges of living in a semi-marine habitat.

Homo sapiens systemic RNA interference-defective-1 transmembrane family member 1 (SIDT1) protein mediates contact-dependent small RNA transfer and microRNA-21-driven chemoresistance.

Locally initiated RNA interference (RNAi) has the potential for spatial propagation, inducing posttranscriptional gene silencing in distant cells. In Caenorhabditis elegans, systemic RNAi requires a phylogenetically conserved transmembrane channel, SID-1. Here, we show that a human SID-1 orthologue, SIDT1, facilitates rapid, contact-dependent, bidirectional small RNA transfer between human cells, resulting in target-specific non-cell-autonomous RNAi. Intercellular small RNA transfer can be both homotypic and heterotypic. We show SIDT1-mediated intercellular transfer of microRNA-21 to be a driver of resistance to the nucleoside analog gemcitabine in human adenocarcinoma cells. Documentation of a SIDT1-dependent small RNA transfer mechanism and the associated phenotypic effects on chemoresistance in human cancer cells raises the possibility that conserved systemic RNAi pathways contribute to the acquisition of drug resistance. Mediators of non-cell-autonomous RNAi may be tractable targets for novel therapies aimed at improving the efficacy of current cytotoxic agents.

Implementation of an enhanced recovery programme following pancreaticoduodenectomy.

OBJECTIVES: The aim of this prospective study was to investigate the implementation of an enhanced recovery after surgery (ERAS) programme following pancreaticoduodenectomy (PD). METHODS: Patients undergoing PD were managed according to an ERAS protocol. Outcome measures included postoperative mortality, morbidity, hospitalization and 30-day readmission rate. Key protocol targets were: nasogastric tube (NGT) removal [postoperative day (PoD) 1]; resumption of oral fluids (PoD 1); urinary catheter removal (PoD 3); high-dependency unit (HDU) discharge (PoD 3); tolerating diet (PoD 4); drain removal (PoD 5), and hospital discharge (PoD 6). RESULTS: Data were collected for 50 patients (24 male; median age 67 years). Rates of mortality, morbidity and readmission were 4%, 46% and 4%, respectively. The median length of postoperative hospitalization was 10 days. The proportions of patients achieving key targets were: 78% for NGT removal; 82% for resumption of oral fluids; 48% for urinary catheter removal; 82% for HDU discharge; 86% for tolerating diet; 84% for meeting mobility targets, and 72% for drain removal. One patient was discharged by PoD 6, eight patients by PoD 7, 15 patients by PoD 8 and 26 patients (52%) by PoD 10. Discharge was delayed in 16 patients for social or transport-related reasons. CONCLUSIONS: The ERAS protocol was implemented safely. Achieving certain targets was challenging. Non-medical causes remain a significant factor in delayed discharge following PD.

Is the Glycoprotein Responsible for the Differences in Dispersal Rates between Lettuce Necrotic Yellows Virus Subgroups?

Lettuce necrotic yellows virus is a type of species in the Cytorhabdovirus genus and appears to be endemic to Australia and Aotearoa New Zealand (NZ). The population of lettuce necrotic yellows virus (LNYV) is made up of two subgroups, SI and SII. Previous studies demonstrated that SII appears to be outcompeting SI and suggested that SII may have greater vector transmission efficiency and/or higher replication rate in its host plant or insect vector. Rhabdovirus glycoproteins are important for virus-insect interactions. Here, we present an analysis of LNYV glycoprotein sequences to identify key features and variations that may cause SII to interact with its aphid vector with greater efficiency than SI. Phylogenetic analysis of glycoprotein sequences from NZ isolates confirmed the existence of two subgroups within the NZ LNYV population, while predicted 3D structures revealed the LNYV glycoproteins have domain architectures similar to Vesicular Stomatitis Virus (VSV). Importantly, changing amino acids at positions 244 and 247 of the post-fusion form of the LNYV glycoprotein altered the predicted structure of Domain III, glycosylation at N248 and the overall stability of the protein. These data support the glycoprotein as having a role in the population differences of LNYV observed between Australia and New Zealand.

Giant haemangioma of the liver: observation or resection?

BACKGROUND: Haemangiomata are the most frequent benign solid liver lesion. The management of giant (> or =5 cm) haemangiomata of the liver remains controversial. METHODS: A search of relevant peer-reviewed literature was conducted using PubMed and original articles were reviewed. RESULTS AND CONCLUSIONS: The vast majority of giant haemangiomata remain asymptomatic and have a benign and uncomplicated natural history. Decisions regarding the optimal management of giant haemangiomata depend on a high level of confidence in diagnostic imaging. Diagnostic biopsy to differentiate giant haemangiomata from malignant lesions should be discouraged. Despite limitations and alternative modalities, surgery remains the only consistently effective curative treatment for giant haemangiomata. Surgery is not generally justified to prevent complications in asymptomatic patients. Principal indications for the surgical management of giant haemangiomata include established complications, incapacitating symptoms and uncertainty of diagnosis. Patients should only be selected for surgery based on a careful assessment of risks and benefits of intervention.

Systematic review of postdischarge oral nutritional supplementation in patients undergoing GI surgery.

OBJECTIVE: To determine whether nutritional supplementation following hospital discharge in patients who undergo gastrointestinal (GI) surgery is beneficial in specific outcome measures. METHODS: A systematic review was conducted of randomized controlled trials comparing nutritional supplements vs a "standard care" regimen given to patients following discharge from hospital after GI surgery. Outcome measures were weight change, quality of life, clinical complications, fatigue, and hand grip strength. RESULTS: Four studies were identified. Postdischarge oral nutritional supplements were found to be safe and increased energy intake, protein intake, and weight in patients after discharge from hospital. The greatest gains in weight were seen in malnourished patients. Little evidence was found that nutritional supplements reduce morbidity or improve quality of life, fatigue, or hand-grip strength. Only one study was methodologically adequate, and none were powered to detect differences in clinical complications. CONCLUSIONS: In patients who undergo GI surgery and receive nutritional supplements after discharge from hospital, little evidence of clinical benefit was found, principally through lack of robust data. All the studies were under-powered or not specifically designed to show benefit during this period. It is recommended that nutritional supplements be offered to malnourished patients or those at high risk of poor dietary intake at discharge from hospital.

RNA interference demonstrates a novel role for integrin-linked kinase as a determinant of pancreatic adenocarcinoma cell gemcitabine chemoresistance.

Integrin-linked kinase (ILK) facilitates signal transduction between extracellular events and important intracellular survival pathways involving protein kinase B/Akt. We examined the role of ILK in determining pancreatic adenocarcinoma cellular chemoresistance to the nucleoside analogue gemcitabine. Cellular ILK expression was quantified by Western blot analysis. We examined the effects of overexpression of active ILK and of ILK knockdown induced by RNA interference on gemcitabine chemoresistance. We also examined the effects of modulating ILK expression on gemcitabine-induced caspase 3-mediated apoptosis, phosphorylation status of Akt (Ser473) and glycogen synthase kinase. Overexpression of ILK increased cellular gemcitabine chemoresistance, whereas ILK knockdown induced chemosensitization via increased caspase 3-mediated apoptosis. ILK knockdown attenuated Akt Ser473 and glycogen synthase kinase phosphorylation, whereas overexpression of constitutively active myristoylated Akt was sufficient to induce significant recovery in gemcitabine chemoresistance in the presence of ILK knockdown. Levels of ILK expression affect gemcitabine chemoresistance in pancreatic adenocarcinoma cells. This novel finding suggests that therapies directed against ILK and its downstream signaling targets may have the potential to enhance the efficacy of gemcitabine-based chemotherapy.

A novel role for carcinoembryonic antigen-related cell adhesion molecule 6 as a determinant of gemcitabine chemoresistance in pancreatic adenocarcinoma cells.

Most patients with pancreatic adenocarcinoma present with surgically incurable disease. Gemcitabine, the principal agent used to treat such patients, has little impact on outcome. Overexpression of carcinoembryonic antigen-related cell adhesion molecule (CEACAM) 6, a feature of this malignancy, is associated with resistance to anoikis and increased metastasis. The purpose of this study was to determine the role of CEACAM6 in cellular chemoresistance to gemcitabine. CEACAM6 was stably overexpressed in Capan2 cells, which inherently express very low levels of the protein. Suppression of CEACAM6 expression was achieved in BxPC3 cells, which inherently overexpress CEACAM6, by stable transfection of a CEACAM6 small interfering RNA-generating vector. The effects of modulating CEACAM6 expression on gemcitabine-induced cytotoxicity were determined by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide cytotoxicity assay, flow cytometric apoptosis quantification, caspase profiling, and Western analysis of cytoplasmic cytochrome c release. The roles of Akt and c-Src kinases as downstream targets of CEACAM6 signaling were examined. Stable overexpression of CEACAM6 in Capan2 increased gemcitabine chemoresistance, whereas CEACAM6 gene silencing in BxPC3 markedly increased the sensitivity of these cells to gemcitabine. Differential expression of CEACAM6 modulates Akt activity in a c-Src-dependent manner, and CEACAM6 overexpression appears to protect cells from cytochrome c-induced caspase 3 activation and apoptosis.

Prostaglandin E2 enhances pancreatic cancer invasiveness through an Ets-1-dependent induction of matrix metalloproteinase-2.

Accumulating evidence suggests an important role for cyclooxygenase-2 (COX-2) in the pathogenesis of a wide range of malignancies. Here we tested the hypothesis that the COX-2 product prostaglandin E(2) (PGE(2)) increases cellular invasive potential by inducing matrix metalloproteinase-2 (MMP-2) expression and activity through an extracellular signal-regulated kinase (ERK)/Ets-1-dependent mechanism in pancreatic cancer. PANC-1 and MIAPaCa-2 pancreatic cancer cells were treated with PGE(2) or rofecoxib, a selective COX-2 inhibitor. MMP-2 expression and activity were assayed using Western blot analysis and zymography, respectively. MMP-2 promoter activity was analyzed with a luciferase-based assay. Ets-1 activity was analyzed using gel shift assay. Ets-1 expression was specifically silenced using RNA interference. Cellular invasive and migratory potentials were determined using a Boyden chamber assay with or without Matrigel, respectively. Exogenous PGE(2) induced MMP-2 expression and activity and increased ERK1/2 phosphorylation, Ets-1 binding activity, and MMP-2 promoter activity. PGE(2) also increased cellular migratory and invasive potentials. The mitogen-activated protein kinase kinase inhibitor PD98059 and Ets-1 silencing each abolished PGE(2)-induced increases in MMP-2 expression. PD98059 and Ets-1 silencing each abrogated the effect of PGE(2) on cellular invasive potential but not on cellular migratory potential. Rofecoxib suppressed MMP-2 expression and activity, Ets-1 binding activity, MMP-2 promoter activity, and cellular migratory and invasive potentials. These results suggest that PGE(2) mediates pancreatic cancer cellular invasiveness through an ERK/Ets-1-dependent induction of MMP-2 expression and activity. They also suggest that COX-2 inhibition may represent a strategy to inhibit invasive potential in pancreatic cancer.

Leaf Stable Isotope and Nutrient Status of Temperate Mangroves As Ecological Indicators to Assess Anthropogenic Activity and Recovery from Eutrophication.

We measured nitrogen stable isotope values (δ15N), and total phosphorus (%P) and total nitrogen (%N) contents in leaves of the temperate mangrove (Avicennia marina sp. australasica) from three coastal ecosystems exposed to various levels of human impact (Manukau, high; Mangawhai, low; and Waitemata, intermediate) in northern New Zealand. We measured δ15N values around 10‰ in environments where the major terrestrial water inputs are sewage. The highest average total nitrogen contents and δ15N values were found in the Auckland city region (Manukau Harbour) at 2.2%N and 9.9‰, respectively. The lowest values were found in Mangawhai Harbour, situated about 80 km north of Auckland city, at 2.0%N and 5.2‰, respectively. In the Waitemata Harbour, also located in Auckland city but with less exposure to human derived sewage inputs, both parameters were intermediate, at 2.1%N and 6.4‰. Total phosphorus contents did not vary significantly. Additionally, analysis of historical mangrove leaf herbarium samples obtained from the Auckland War Memorial Museum indicated that a reduction in both leaf total nitrogen and δ15N content has occurred over the past 100 years in Auckland's harbors. Collectively, these results suggest that anthropogenically derived nitrogen has had a significant impact on mangrove nutrient status in Auckland harbors over the last 100 years. The observed decrease in nitrogenous nutrients probably occurred due to sewage system improvements. We suggest that mangrove plant physiological response to nutrient excess could be used as an indicator of long-term eutrophication trends. Monitoring leaf nutrient status in mangroves can be used to assess environmental stress (sewage, eutrophication) on coastal ecosystems heavily impacted by human activities. Moreover, nitrogen and phosphorus leaf contents can be used to assess levels of available nutrients in the surrounding environments.

EphA2: a determinant of malignant cellular behavior and a potential therapeutic target in pancreatic adenocarcinoma.

The EphA2 receptor tyrosine kinase is overexpressed in a variety of human cancers. We sought to characterize the role of EphA2 in pancreatic adenocarcinoma and, using RNA interference (RNAi) mediated by small interfering RNA (siRNA), we determined the effects of suppressing EphA2 expression in vitro and in vivo. EphA2 expression in PANC1, MIAPaCa2, BxPC3 and Capan2 cells was assessed by Northern and Western blot. We artificially overexpressed EphA2 by transient transfection and suppressed EphA2 expression using RNAi. Cellular invasiveness was quantified by modified Boyden chamber assay. Anoikis was induced by anchorage-independent polyHEMA culture and caspase 3 activity was quantified fluorometrically. Focal adhesion kinase (FAK) phosphorylation was assessed by immunoprecipitation. EphA2 siRNA treatment was assessed in a nude mouse xenograft model. Pancreatic adenocarcinoma cells differentially express EphA2. Inherent and induced EphA2 overexpression is associated with increased cellular invasiveness and anoikis resistance. EphA2 siRNA suppresses EphA2 expression, cellular invasiveness, anoikis resistance and FAK phosphorylation in vitro and retards tumor growth and inhibits metastasis in vivo. EphA2 is both a determinant of malignant cellular behavior and a potential therapeutic target in pancreatic adenocarcinoma.

CEACAM6 gene silencing impairs anoikis resistance and in vivo metastatic ability of pancreatic adenocarcinoma cells.

Anoikis is the apoptotic response induced in normal cells by inadequate or inappropriate adhesion to substrate. It is postulated that resistance to anoikis facilitates tumorigenesis and metastasis. Carcinoembryonic antigen-related cell adhesion molecule 6 (CEACAM6) is an immunoglobulin superfamily member overexpressed in a number of human cancers and implicated in anoikis resistance. We tested the effect of CEACAM6 gene silencing on anoikis in pancreatic adenocarcinoma cell lines. Anoikis was induced in PANC1, Capan2, MiaPaCa2 and Mia(AR) (a MiaPaCa2-derived anoikis-resistant subline) by culture in poly-2-hydroxyethylmethacrylate-coated wells. Anoikis was quantified by YO-PRO-1/propidium iodide staining and flow cytometry. The role of caspase activation was determined using fluorometric profiling and the caspase inhibitor Z-Val-Ala-Asp-fluoromethyl ketone (Z-VAD-fmk). CEACAM6 expression was suppressed by RNA interference. Using a nude mouse orthotopic xenograft model, we assessed the effect of this treatment on in vivo metastatic ability. Anoikis resistance was associated with increased CEACAM6 expression. CEACAM6-specific short interfering ribonucleic acid (siRNA), but not control siRNA, increased susceptibility to caspase-mediated anoikis, an effect abrogated by Z-VAD-fmk, and decreased Akt phosphorylation (Ser-473) under anchorage-independent conditions. CEACAM6 gene silencing reversed the acquired anoikis resistance of Mia(AR) and inhibited its in vivo metastatic ability. CEACAM6 warrants further investigation as a novel therapeutic target for the treatment of pancreatic adenocarcinoma.