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Groove pancreatitis (GP) is an underrecognised subtype of chronic pancreatitis, focally affecting the area between the duodenum and pancreatic head. It most commonly affects males between 40 and 50 years of age with a history of alcohol misuse. Patients most commonly complain of abdominal pain and vomiting. Due to its focal nature, it is a potentially surgically treatable form of chronic pancreatitis. We report results of patients surgically treated for groove pancreatitis followed by a literature review of patient outcomes post resection.A retrospective chart review of patients with histopathologically confirmed GP post-surgical resection at the Princess Alexandra Hospital and Greenslopes Private Hospital in Brisbane, Australia was conducted between 2013 and 2020. Diagnosis was confirmed histologically when Brunner gland hyperplasia and chronic inflammation/fibrosis were found within the pancreaticoduodenal interface. Preoperative and postoperative symptoms were analysed along with complications. Additionally, a systematic review on outcomes of patients undergoing pancreaticoduodenectomy (PD) for GP was performed from three databases.Eight patients underwent surgery for GP. Elimination of preoperative symptoms was achieved in five of the eight patients. Major complications included one take back to theatre for pancreatic leak. Our literature review found complete resolution of pain and vomiting in 80% of GP patients after PD.Optimal management of GP begins with early recognition. Symptoms from GP are likely to respond well to surgical intervention. We advocate for aggressive surgical resection in a patient with a high index of suspicion for GP.

The induced membrane technique is a simple, effective, and reproducible treatment method for segmental bone defects. It is a 2-stage approach that requires eventual autologous bone graft to manage the deficit. The first stage requires debridement of all nonviable tissue while preserving a healthy soft tissue envelope. A polymethylmethacrylate is implanted between the osseous segments to maintain length. The osseous defect can be stabilized internally or externally. During the second stage, a vascularized induced membrane is formed and produces multiple growth factors. The induced membrane technique is a valuable option for limb salvage in cases of segmental bone defects.

Radical prostatectomy (RP) is a common treatment choice for localized prostate cancer. While there is increasing utilisation of robotic assisted RP in some centres, open RP (ORP) remains well established and commonly performed in many parts of the world. The goals of modern ORP are to remove the prostate en-bloc with negative surgical margins, while minimising blood loss and preserving urinary continence and erectile function. We present a technical review of ORP incorporating contemporary techniques for control of the deep venous complex, additional haemostatic measures, nerve-sparing and vesicourethral reconstruction.

New computer technology is often seen as the key to the future of manufacturing. Much of the research on the benefits of technology has focused on automation in the factory and its effects on produ...

The flow (flux) of climate-critical gases, such as carbon dioxide (CO2), between the ocean and the atmosphere is a fundamental component of our climate and an important driver of the biogeochemical systems within the oceans. Therefore, the accurate calculation of these air–sea gas fluxes is critical if we are to monitor the oceans and assess the impact that these gases are having on Earth's climate and ecosystems. FluxEngine is an open-source software toolbox that allows users to easily perform calculations of air–sea gas fluxes from model, in situ, and Earth observation data. The original development and verification of the toolbox was described in a previous publication. The toolbox has now been considerably updated to allow for its use as a Python library, to enable simplified installation, to ensure verification of its installation, to enable the handling of multiple sparingly soluble gases, and to enable the greatly expanded functionality for supporting in situ dataset analyses. This new functionality for supporting in situ analyses includes user-defined grids, time periods and projections, the ability to reanalyse in situ CO2 data to a common temperature dataset, and the ability to easily calculate gas fluxes using in situ data from drifting buoys, fixed moorings, and research cruises. Here we describe these new capabilities and demonstrate their application through illustrative case studies. The first case study demonstrates the workflow for accurately calculating CO2 fluxes using in situ data from four research cruises from the Surface Ocean CO2 ATlas (SOCAT) database. The second case study calculates air–sea CO2 fluxes using in situ data from a fixed monitoring station in the Baltic Sea. The third case study focuses on nitrous oxide (N2O) and, through a user-defined gas transfer parameterisation, identifies that biological surfactants in the North Atlantic could suppress individual N2O sea–air gas fluxes by up to 13 %. The fourth and final case study illustrates how a dissipation-based gas transfer parameterisation can be implemented and used. The updated version of the toolbox (version 3) and all documentation is now freely available.

Acute pancreatitis (AP) is one of the most common general acute surgical presentations. Current recommendations are that idiopathic acute pancreatitis (IAP) should account for no more than 20% of AP cases. Some studies suggest gallbladder microlithiasis is the aetiology in up to 75% of IAP patients. Endoscopic ultrasound (EUS) has been reported to be effective in the detection of microlithiasis and choledocholithiasis as well as pancreatic parenchymal, ductal and ampullary disorders. The aims of this study were to evaluate the usefulness of EUS in establishing aetiology in IAP patients and to assess if there is a role for EUS in the selection criteria for laparoscopic cholecystectomy to treat a potential biliary cause in IAP patients. A systematic review following PRISMA guideline was performed to gather data on patients with IAP undergoing EUS for further investigation. Three databases (MEDLINE, PubMed, and EMBASE) were searched to 28 July 2018. Our systematic review included 28 studies, comprising 1850 patients with an initial diagnosis of IAP prior to having EUS. Diagnosis of a potential aetiology or associated pancreatic pathology was established in 1095 (62%, p

Connecting tropical rainforests to larger rivers, tropical headwaters export large quantities of carbon and nutrients as dissolved organic matter (DOM), and are thus a key component of the global carbon cycle. This DOM transport is not passive, however; sunlight and microbial activity alter DOM concentrations and compositions, affecting riverine greenhouse gas emissions and downstream ecosystems. The effects of sunlight and microbial turnover/activity on DOM concentrations and compositions in tropical headwaters are currently poorly understood, but novel Size Exclusion Chromatography (SEC) techniques coupled to suitable detectors can for the first time quantify their influences. Here, we present in-situ incubation experiments from from headwaters of the Essequibo River, in the Iwokrama Rainforest, Guyana, where sunlight oxidised up to 9% of dissolved organic carbon (DOC) over 12 hours, at higher rates than in larger tropical rivers. DOM transformations occurred in both photo-sensitive and supposedly photo-resistant pools. Microbial activity had varying, less clear influences on DOC concentrations over the same time span; compositionally, this appeared to extend beyond known bio-labile components. Biopolymers were particularly reactive to both processes. We show sunlight has the greater potential to mineralise headwater DOM and thus potentially influence degassing. Our approach provides a future template to constrain DOM transformations along river networks, identify biogeochemical activity hotspots, and improve greenhouse gas emissions estimations under changing environmental conditions.

The environmental, social and political challenges of the twenty-first century are interconnected and interdependent: they are systemic. To address these challenges systemically, systems thinking and ecoliteracy skills need to be communicated and promoted. We present a combined physical and virtual reality game experience that invites players to become climate scientists in the Amazon rainforest and role play as participants at a UN climate summit. This aims to achieve environmental transformational change where, traditionally, presentation of research alone has not been effective.

Prototypes have long been deemed critical to the success of product development, yet there has been little formal study of the tradeoffs between different alternative prototype forms. We propose a normative model that enables the selection of an appropriate prototype typology for a given product type. Based on observations from 11 different firms, we explore the tension between the cost effectiveness and ease of iteration of virtual prototypes versus the high-fidelity yet more costly physical prototypes. We discovered that the selection of prototype states primarily depends on the product newness and we were able to propose a decision model for typology selection with the other variables being the aesthetic and structural requirements of the product. We generated eight propositions based on our grounded theory study and we were able to expand the boundary of the known benefits and risks of the various prototype states.

Ocean CO2 uptake accounts for 20–40% of the post-industrial sink for anthropogenic CO2. The uptake rate is the product of the CO2 interfacial concentration gradient and its transfer velocity, which is controlled by spatial and temporal variability in near-surface turbulence. This variability complicates CO2 flux estimates and in large part reflects variable sea surface microlayer enrichments in biologically derived surfactants that cause turbulence suppression. Here we present a direct estimate of this surfactant effect on CO2 exchange at the ocean basin scale, with derived relationships between its transfer velocity determined experimentally and total surfactant activity for Atlantic Ocean surface seawaters. We found up to 32% reduction in CO2 exchange relative to surfactant-free water. Applying a relationship between sea surface temperature and total surfactant activity to our results gives monthly estimates of spatially resolved ‘surfactant suppression’ of CO2 exchange. Large areas of reduced CO2 uptake resulted, notably around 20° N, and the magnitude of the Atlantic Ocean CO2 sink for 2014 was decreased by 9%. This direct quantification of the surfactant effect on CO2 uptake at the ocean basin scale offers a framework for further refining estimates of air–sea gas exchange up to the global scale. Biologically produced surfactants in the sea surface microlayer reduce air–sea exchange of CO2 in the North Atlantic Ocean, according to tank and ocean measurements.

The sural flap procedure is a versatile technique that can be used to cover many types of defects about the lower extremity. The management of soft tissue defects of the lower extremity with underlying osteomyelitis is difficult. The goal for any of these patients is to create a biomechanically stable foot for weight-bearing purposes with no continued infection. Data were gathered using multiple databases from the years 2000 to 2016. Data were compiled looking at the number of subjects, age, comorbidities, number of complications, number of failures, and average flap size of complications/failures. A total of 110 patients were gathered using 5 separate articles. Twenty-two of the 110 patients had short-term complications. Flap failure was seen in 9/110 patients. A significant difference was noticed in flap size between flap failure and complication groups and nonfailure groups. The average flap size of patients who had some form of complication or failure was 51.87 cm2 in size. The average graft size for patients without complications during their recovery was 36.54 cm2. Within our study, the failure rate of 8.9% and complication rate of 13.7% are consistent with previous reports on sural perforator flaps. Last, with regard to the effect of flap size, there were significant differences between patients with a successful outcome and those who experienced complications or failures. Levels of Evidence: Therapeutic, Level III: Systematic review

We report the first measurements of surfactant activity (SA) in the sea surface microlayer (SML) and in sub-surface waters (SSW) at the ocean basin scale, for two Atlantic Meridional Transects (AMT) from 50°N to 50°S during 2014 and 2015. Northern hemisphere (NH) SA was significantly higher than southern hemisphere (SH) SA in the SML and in the SSW. SA enrichment factors (EF = SASML/SASSW) were also higher in the NH, for wind speeds up to ~13 m s-1, questioning a prior assertion that Atlantic Ocean wind speeds > 12 m s-1 poleward of 30°N and 30°S would preclude high EFs and showing the SML to be self-sustaining with respect to SA. Our results imply that surfactants exert a control on air-sea CO2 exchange across the whole North Atlantic CO2 sink region and that the contribution made by high wind, high latitude oceans to air-sea gas exchange globally should be re-examined.

MILAN was a multidisciplinary, international study examining how the diel variability of sea-surface microlayer biogeochemical properties potentially impacts ocean-atmosphere interaction, in order to improve our understanding of this globally important process. The sea-surface microlayer (SML) at the air-sea interface is < 1 mm deep but it is physically, chemically and biologically distinct from the underlying water and the atmosphere above. Wind-driven turbulence and solar radiation are important drivers of SML physical and biogeochemical properties. Given that the SML is involved in all ocean-atmosphere exchanges of mass and energy, its response to solar radiation, especially in relation to how it regulates the air-sea exchange of climate-relevant gases and aerosols, is surprisingly poorly characterised. MILAN (sea-surface MIcroLAyer at Night) was an international, multidisciplinary campaign designed to specifically address this issue. In spring 2017, we deployed diverse sampling platforms (research vessels, radio-controlled catamaran, free-drifting buoy) to study full diel cycles in the coastal North Sea SML and in underlying water, and installed a land-based aerosol sampler. We also carried out concurrent ex situ experiments using several microsensors, a laboratory gas exchange tank, a solar simulator, and a sea spray simulation chamber. In this paper we outline the diversity of approaches employed and some initial results obtained during MILAN. Our observations of diel SML variability, e.g. the influence of changing solar radiation on the quantity and quality of organic material, and diel changes in wind intensity primarily forcing air-sea CO2 exchange, underline the value and the need of multidisciplinary campaigns for integrating SML complexity into the context of air-sea interaction.

A 49-year-old man presented with a 2-week history of gradual onset progressively worsening left upper quadrant pain. Ten months prior, he had a laparoscopic roux-en-Y gastric bypass (LRYGBP) for severe gastro-oesophageal reflux disease and obesity. On examination, his abdomen was not distended and was soft to palpation. The haemoglobin, white cell count, liver function test, lipase and lactate were normal. An abdominal CT scan demonstrated swirl sign. Given the suspicion of internal herniation, laparoscopy was performed demonstrating only partial closure of the jejuno-jejunal mesodefect resulting in herniation of the small bowel alimentary limb. Internal herniation should be considered as a differential diagnosis in all patients with previous LRYGBP and unexplained abdominal pain, nausea or vomiting. If closure of a mesodefect is to be attempted, a running, braided, non-absorbable suture should be used as a purse-string to avoid small defects with subsequent weight and mesenteric fat loss following bariatric surgery.

Three different source waters were investigated using virgin and pre-used anion exchange resins, coagulation, and ion exchange combined with coagulation (IEX&Coagulation). The hydrophobicity, size distribution and charge of natural organic matter (NOM) were used to evaluate its removal. Dissolved organic carbon (DOC) removal by pre-used IEX resin was 67–79%. A consistent ratio of different hydrophobicity fractions was found in the removed DOC, while the proportion and quantity of the molecular weight fraction around 1 kDa was important in understanding the treatability of water. For pre-used resin, organic compounds were hypothesised to be restricted to easily accessible exchange sites. Comparatively, virgin resin achieved higher DOC removals (86–89%) as resin fouling was absent. Charge density and the proportion of the hydrophobic fraction were found to be important indicators for the specific disinfection byproduct formation potential (DBP-FP). Treatment of raw water with pre-used resin decreased the specific DBP-FP by between 2 and 43%, while the use of virgin resin resulted in a reduction of between 31 and 63%. The highest water quality was achieved when the combination of IEX and coagulation was used, reducing DOC and the specific DBP-FP well below that seen for either process alone.

An 81-year-old man presented to medical services with pelvic pain and evolving urinary retention over 3 months. The patient was found to have a tense glans and penile shaft with surrounding induration consistent with malignant priapism. The extent of the induration included the suprapubic region, scrotum, left iliac region and left flank. A CT scan demonstrated an enhancing, pedunculated lesion arising from the anterior bladder wall measuring 30×31×20 mm. There were multiple enlarged left inguinal lymph nodes. Core biopsies of the subcutaneous tissue on the anterior abdominal wall demonstrated plasmacytoid urothelial carcinoma. The majority of patients with plasmacytoid variant of transitional cell carcinoma will present with >stage 3 bladder disease

A 35-year-old man presented to a regional hospital after being kicked by a horse in the right upper quadrant. He was transferred to our hepatobiliary unit with bile peritonitis 8 days post trauma. Laparoscopic cholecystectomy and intraoperative cholangiography were performed, demonstrating distal common bile duct (CBD) obstruction with contrast extravasation from the distal duct. The CBD was drained with a T-tube via laparotomy. On postoperative day 14, T-tube cholangiography demonstrated no extravasation of contrast from the distal CBD and minor stricturing with eventual duodenal drainage. The T-tube was clamped and 5 weeks later, the patient represented with peri-T-tube bile leakage and right upper quadrant pain. A T-tube cholangiogram confirmed a complex distal CBD stricture. Two attempts at ERCP with intent of stenting the stricture were unsuccessful. The patient underwent an end to side Roux-en-Y choledochojejunostomy and was discharged home 4 days postoperatively on simple analgesia.

The flow (flux) of climate critical gases, such as carbon dioxide (CO2), between the ocean and the atmosphere is a fundamental component of our climate and the biogeochemical development of the oceans. Therefore, the accurate calculation of these air-sea gas fluxes is critical if we are to monitor the health of our oceans and changes to our climate. FluxEngine is an open source software toolbox that allows users to easily perform calculations of air-sea gas fluxes from model, in-situ and Earth observation data. The original development and verification of the toolbox was described in a previous publication and the toolbox is already being used by scientists across multiple disciplines. The toolbox has now been considerably updated to allow its use as a Python library, to enable simplified installation, verification of its installation, to enable the handling of multiple sparingly soluble gases and greatly expanded functionality for supporting in situ dataset analyses. This new functionality for supporting in situ analyses includes user defined grids, time periods and projections, the ability to re-analyse in situ CO2 data to a common temperature dataset and the ability to easily calculate gas fluxes using in situ data from drifting buoys, fixed moorings and research cruises. Here we describe these new capabilities and then demonstrate their application through illustrative case studies. The first case study demonstrates the workflow for accurately calculating CO2 fluxes using in situ data from four research cruises from the Surface Ocean CO2 Atlas (SOCAT) database. The second case study shows that reanalysing an eight month time series of pCO2 data collected from a fixed station in the Baltic Sea can remove errors equal to 35 % of the net air-sea gas flux. The third case study demonstrates that biological surfactants could supress individual nitrous oxide sea-air gas fluxes by up to 13 %. The final case study illustrates how a dissipation-based gas transfer parameterisation can be implemented and used. The updated version of the toolbox (version 3) and all documentation is now freely available.

Background Extrahepatic bile duct injuries (EHBDIs) are a rare consequence of blunt abdominal trauma. The purpose of this study was to establish mechanisms of injury, clinical indicators of EHBDI following blunt trauma (both with investigative modalities and intraoperatively), method and timing of injury detection, and definitive treatment options. Methods A systematic review was performed to gather data on patients with an EHBDI secondary to blunt trauma. Three databases (MEDLINE, PubMed, and EMBASE) were searched to July 19, 2018. Results Our systematic review included 51 studies, compromising a study population of 66 patients with EHBDIs sustained from blunt trauma. The three most common injuries included complete transection of the suprapancreatic common bile duct (29%, n = 19), complete transection of the intrapancreatic common bile duct (23%, n = 15) and partial laceration of the left hepatic duct (20%, n = 13). Of the hemodynamically stable group managed nonoperatively (n = 23), mean timing postinjury to diagnosis of EHBDI was 11 days. An EHBDI was recognized at initial laparotomy in 87% (n = 13) of hemodynamically stable patients. An EHBDI was recognized at initial laparotomy in 57% (n = 8) of hemodynamically unstable patients. Conclusion The EHBDIs are a rare yet serious consequence of blunt trauma. To establish a timely diagnosis and limit complications of missed injuries, a heightened awareness is required by the attending surgeon with particular attention to subtle yet important clinical indicators. These vary depending on the hemodynamic stability of the patient and decision to manage injuries conservatively or surgically on presentation. Level of evidence Systematic review, level III.

Background A left-sided gallbladder (LSGB) is a rare anatomical anomaly that is often not discovered until surgery. Two cases of LSGB managed with laparoscopic cholecystectomy (LC) stimulated this systematic review. The aims of this study were in LSGB to define the rate of pre-operative detection, variations in biliary anatomy, laparoscopic techniques employed and outcomes of surgery for symptomatic gallstones. Methods A systematic review was performed using Preferred Reporting Items for Systematic reviews and Meta-Analyses principles. Results Fifty-three studies with 112 patients of which 90 (80.4%) had symptomatic gallstones. Pre-operative imaging was performed in 108 patients (96.4%) with an LSGB reported on imaging in 32 (29.6%) patients. The remainder of LSGB were discovered at surgery. Ultrasound detected an LSGB in three (2.7%) patients. Five variants of cystic union with the common hepatic duct (CHD) were identified. The most common (67.8%) was union on the right side of the CHD after a hairpin bend anterior to the CHD. A cholecystectomy for gallstone disease was performed in 90 patients, 23.3% open and 76.7% LC. Common variations in LC technique were different port site placement and techniques related to the falciform ligament to improve exposure. Common bile duct injury occurred in four (4.4%) patients. Conclusion LSGB is a rare anatomical variation that in patients with symptomatic gallstones is usually discovered at surgery. Cholecystectomy is associated with a higher incidence of common bile duct injury.

Despite decades of imitation and apparent convergence, there are still major differences in product development practices between Japanese automakers and their North American counterparts. Through an in-depth investigation of product development practices at the project level, we study two firms-Toyota and a major North American automaker-that possess very different approaches to product development. We take the perspective of a major supplier to both automakers. Adopting a grounded theory approach and by selecting similar projects performed by the same supplier for different original equipment manufacturer (OEM) customers, we hold constant variables such as product, supplier, and period of observation. We find that the lack of best practice proliferation in product development can be explained by a lack of organizational culture that sustains and facilitates best practices. We view our results through the lens of cultural frameworks offered in the literature and derive a model linking organizational culture to product development effectiveness.

Small bowel diaphragm disease (SBDD) is characterised by circumferential lesions of short length (

Biliary colic is a pain in the right upper quadrant or epigastrium thought to be caused by functional gallbladder spasm from a temporary obstructing stone in the gallbladder neck, cystic duct or common bile duct. A 56-year-old man presented with frequent episodes of typical biliary colic. At initial laparoscopy, the gallbladder was absent from its anatomic location. Further inspection revealed a left-sided gallbladder (LSGB), suspended from liver segment 3. Preoperative ultrasound, the most common imaging modality for symptomatic gallstones, has a low positive predictive value for detecting LSGB (2.7%). Laparoscopic cholecystectomy (LC) was delayed to attain additional imaging. A magnetic resonance cholangiopancreatography demonstrated the gallbladder left of the falciform ligament with the cystic duct entering the common hepatic duct from the left. The patient underwent an elective LC 8 weeks later. The critical view of safety is paramount to safe surgical dissection and could be safely achieved for LSGB.

The dense, intact rainforests of the Guianas (northern Amazonia) are important for the regulation of the local and regional climate, but preclude easy access so a large data gap exists. The rainforest–savannah boundary may also be particularly susceptible to increasing pressures from ecosystem exploitation and climate change. It is important therefore to establish a baseline climate regime so that the impacts of any future change can be determined. Currently this area is not covered by the publicly available climate data sets, so interpolated data sets are not an accurate representation of the climate of this area, emphasizing the need for a more detailed analysis in this region. Here, we collate the available data sets and use these to derive maps of observed precipitation and temperature across the region. To overcome the limitations in the inadequate observational data sets, we also test and use the ECMWF ERA-40 reanalysis data set for the period 1958–2001 at a ∼125 km2 (1.125°) resolution. Mean differences (biases) and annual average spatial correlations are examined between modelled and observed time series comparing the seasonal cycles and the yearly, monthly and monthly anomaly time series. The results show that with the exception of sub-grid resolution mountain environments, reanalysis data for the Guianas provide a consistent and relatively accurate spatial distribution of temperature. Precipitation is modelled less accurately, with best results for the average timings, length and severity of the dry periods. This study provides consistent and quantitative details on the spatial variations in seasonality, particularly in areas lacking observations, thereby advancing beyond previous studies. Precipitation is highly variable in the region so care must be taken when averaging modelled data over large geographical areas for comparisons with gridded data sets based on few observations. This is the first comprehensive study of the recent historical climate and its variability in this area. Copyright © 2011 The Authors. Journal compilation © 2011 The Royal Meteorological Society

A 57-year-old man presented with a 6-month history of pelvic fullness. He had no lower urinary tract symptoms or altered bowel habits. On examination, there was a non-tender pelvic mass which extended from the pubic symphysis to the level of the umbilicus. CT scan of the abdomen demonstrated a 22×11×11 cm cystic mass arising from the pelvis extending into the midline and superiorly to the umbilicus. Other than raised carcinoembryonic antigen of 7.6 ng/mL (

In the version of this Article originally published, in the ‘Acknowledgements’ section the authors neglected to include the following text: “The Surface Ocean CO2 Atlas (SOCAT) is an international effort, endorsed by the International Ocean Carbon Coordination Project (IOCCP), the Surface Ocean Lower Atmosphere Study (SOLAS) and the Integrated Marine Biosphere Research (IMBeR) programme, to deliver a uniformly quality-controlled surface ocean CO2 database. The many researchers and funding agencies responsible for the collection of data and quality control are thanked for their contributions to SOCAT.” This has now been added in the online versions of the Article.

The rhodopsin/transducin-coupled vertebrate vision system has served as a paradigm for G protein-coupled signaling. We have taken advantage of this system to identify new types of constitutively active, transducin-alpha (alphaT) subunits. Here we have described a novel dominant-negative mutation, made in the background of a chimera consisting of alphaT and the alpha subunit of G(i1) (designated alphaT*), which involves the substitution of a conserved arginine residue in the conformationally sensitive Switch 3 region. Changing Arg-238 to either lysine or alanine had little or no effect on the ability of alphaT* to undergo rhodopsin-stimulated GDP-GTP exchange, whereas substituting glutamic acid for arginine at this position yielded an alphaT* subunit (alphaT*(R238E)) that was incapable of undergoing rhodopsin-dependent nucleotide exchange and was unable to bind or stimulate the target/effector enzyme (cyclic GMP phosphodiesterase). Moreover, unlike the GDP-bound forms of alphaT*, alphaT*(R238A) and alphaT*(R238K), the alphaT*(R238E) mutant did not respond to aluminum fluoride (AlF4(-)), as read out by changes in Trp-207 fluorescence. However, surprisingly, we found that alphaT*(R238E) effectively blocked rhodopsin-catalyzed GDP-GTP exchange on alphaT*, as well as rhodopsin-stimulated phosphodiesterase activity. Analysis by high pressure liquid chromatography indicated that the alphaT*(R238E) mutant exists in a nucleotide-free state. Nucleotide-free forms of G alpha subunits were typically very sensitive to proteolytic degradation, but alphaT*(R238E) exhibited a resistance to trypsin-proteolysis similar to that observed with activated forms of alphaT*. Overall, these findings indicated that by mutating a single residue in Switch 3, it is possible to generate a unique type of dominant-negative G alpha subunit that can effectively block signaling by G protein-coupled receptors.

Ran (Ras-related nuclear) protein, a member of the Ras superfamily of GTPases, is best known for its roles in nucleocytoplasmic transport, mitotic spindle fiber assembly, and nuclear envelope formation. Recently, we have shown that the overexpression of Ran in fibroblasts induces cellular transformation and tumor formation in mice (Ly, T. K., Wang, J., Pereira, R., Rojas, K. S., Peng, X., Feng, Q., Cerione, R. A., and Wilson, K. F. (2010) J. Biol. Chem. 285, 5815-5826). Here, we describe a novel activated Ran mutant, Ran(K152A), which is capable of an increased rate of GDP-GTP exchange and an accelerated GTP binding/GTP hydrolytic cycle compared with wild-type Ran. We show that its expression in NIH-3T3 fibroblasts induces anchorage-independent growth and stimulates cell invasion, as well as activates signaling pathways that lead to extracellular regulated kinase (ERK) activity. Furthermore, Ran(K152A) expression in the human mammary SKBR3 adenocarcinoma cell line gives rise to an enhanced transformed phenotype and causes a robust stimulation of both ERK and the N-terminal c-Jun kinase (JNK). Microarray analysis reveals that the expression of the gene encoding SMOC-2 (secreted modular calcium-binding protein-2), which has been shown to synergize with different growth factors, is increased by at least 50-fold in cells stably expressing Ran(K152A) compared with cells expressing control vector. Knocking down SMOC-2 expression greatly reduces the ability of Ran(K152A) to stimulate anchorage-independent growth in NIH-3T3 cells and in SKBR3 cells and also inhibits cell invasion in fibroblasts. Collectively, our findings highlight a novel connection between the hyper-activation of the small GTPase Ran and the matricellular protein SMOC-2 that has important consequences for oncogenic transformation.

Although the small GTPase Ran is best known for its roles in nucleocytoplasmic transport, mitotic spindle assembly, and nuclear envelope formation, recent studies have demonstrated the overexpression of Ran in multiple tumor types and that its expression is correlated with a poor patient prognosis, providing evidence for the importance of this GTPase in cell growth regulation. Here we show that Ran is subject to growth factor regulation by demonstrating that it is activated in a serum-dependent manner in human breast cancer cells and, in particular, in response to heregulin, a growth factor that activates the Neu/ErbB2 tyrosine kinase. The heregulin-dependent activation of Ran requires mTOR (mammalian target of rapamycin) and stimulates the capped RNA binding capability of the cap-binding complex in the nucleus, thus influencing gene expression at the level of mRNA processing. We further demonstrate that the excessive activation of Ran has important consequences for cell growth by showing that a novel, activated Ran mutant is sufficient to transform NIH-3T3 cells in an mTOR- and epidermal growth factor receptor-dependent manner and that Ran-transformed cells form tumors in mice.