383 research outputs found

    Influence of temperature on the electrochemical window of boron doped diamond: a comparison of commercially available electrodes

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    This work compares the electrochemical windows of polished and unpolished boron doped diamond (BDD) electrodes with hydrogen and oxygen terminations at a series of temperatures up to 125 °C. The experiment was run at 5 bar pressure to avoid complications due to bubble formation. An alternative method for determining the electrochemical window is compared to the most commonly used method, which defines the window at an arbitrary current density cut-off (Jcut-off) value. This arbitrary method is heavily influenced by the mass transport of the electrolyte and cannot be used to compare electrodes across literature where different Jcut-off values have been used. A linear fit method is described which is less affected by the experimental conditions in a given measurement system. This enables a more accurate comparison of the relative electrochemical window from various diamond electrode types from reported results. Through comparison of polished and unpolished BDD electrodes, with hydrogen and oxygen surface terminations, it is determined that the electrochemical window of BDD electrodes narrows as temperature increases; activation energies are reported

    Exploiting inflammation for therapeutic gain in pancreatic cancer

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    Pancreatic ductal adenocarcinoma (PDAC) is an aggressive malignancy associated with <5% 5-year survival, in which standard chemotherapeutics have limited benefit. The disease is associated with significant intra- and peritumoral inflammation and failure of protective immunosurveillance. Indeed, inflammatory signals are implicated in both tumour initiation and tumour progression. The major pathways regulating PDAC-associated inflammation are now being explored. Activation of leukocytes, and upregulation of cytokine and chemokine signalling pathways, both have been shown to modulate PDAC progression. Therefore, targeting inflammatory pathways may be of benefit as part of a multi-target approach to PDAC therapy. This review explores the pathways known to modulate inflammation at different stages of tumour development, drawing conclusions on their potential as therapeutic targets in PDAC

    Kinome rewiring reveals AURKA limits PI3K-pathway inhibitor efficacy in breast cancer.

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    Dysregulation of the PI3K-AKT-mTOR signaling network is a prominent feature of breast cancers. However, clinical responses to drugs targeting this pathway have been modest, possibly because of dynamic changes in cellular signaling that drive resistance and limit drug efficacy. Using a quantitative chemoproteomics approach, we mapped kinome dynamics in response to inhibitors of this pathway and identified signaling changes that correlate with drug sensitivity. Maintenance of AURKA after drug treatment was associated with resistance in breast cancer models. Incomplete inhibition of AURKA was a common source of therapy failure, and combinations of PI3K, AKT or mTOR inhibitors with the AURKA inhibitor MLN8237 were highly synergistic and durably suppressed mTOR signaling, resulting in apoptosis and tumor regression in vivo. This signaling map identifies survival factors whose presence limits the efficacy of targeted therapies and reveals new drug combinations that may unlock the full potential of PI3K-AKT-mTOR pathway inhibitors in breast cancer

    BIM mediates synergistic killing of B-cell acute lymphoblastic leukemia cells by BCL-2 and MEK inhibitors

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    B-cell acute lymphoblastic leukemia (B-ALL) is an aggressive hematological disease that kills ~50% of adult patients. With the exception of some BCR-ABL1(+) patients who benefit from tyrosine kinase inhibitors, there are no effective targeted therapies for adult B-ALL patients and chemotherapy remains first-line therapy despite adverse side effects and poor efficacy. We show that, although the MEK/ERK pathway is activated in B-ALL cells driven by different oncogenes, MEK inhibition does not suppress B-ALL cell growth. However, MEK inhibition synergized with BCL-2/BCL-XL family inhibitors to suppress proliferation and induce apoptosis in B-ALL cells. We show that this synergism is mediated by the pro-apoptotic factor BIM, which is dephosphorylated as a result of MEK inhibition, allowing it to bind to and neutralize MCL-1, thereby enhancing BCL-2/BCL-XL inhibitor-induced cell death. This cooperative effect is observed in B-ALL cells driven by a range of genetic abnormalities and therefore has significant therapeutic potential

    Immunobiological effects of gemcitabine and capecitabine combination chemotherapy in advanced pancreatic ductal adenocarcinoma

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    Background: Preclinical studies suggest that chemotherapy may enhance the immune response against pancreatic cancer. Methods: The levels of granulocyte macrophage-colony-stimulating factor (GM-CSF) and interleukin-6 (IL-6) and the associated inflammatory marker C-reactive protein (CRP) were assessed in 38 patients receiving gemcitabine and capecitabine combination chemotherapy for advanced pancreatic cancer within the TeloVac trial. Apoptosis (M30) and total immune response (delayed-type hypersensitivity and/or T-cell response) were also assessed and levels of apoptosis induction correlated with immune response. The telomerase GV1001 vaccine was given either sequentially (n=18) or concomitantly (n=24) with the combination chemotherapy. Results: There were no differences between baseline and post-treatment levels of CRP (P=0.19), IL-6 (P=0.19) and GM-CSF (P=0.71). There was a positive correlation between post-chemotherapy CRP and IL-6 levels (r=0.45, P=0.005) and between CRP with carbohydrate antigen-19-9 (CA19-9) levels at baseline (r=0.45, P=0.015) and post treatment (r=0.40, P=0.015). The change in CRP and IL-6 levels was positively correlated (r=0.40, P=0.012). Hazard ratios (95% CI) for baseline CA19-9 (1.30 (1.07–1.59), P=0.009) and CRP (1.55 (1.00–2.39), P=0.049) levels were each independently predictive of survival. The M30 mean matched differences between pre- and post-chemotherapy showed evidence of apoptosis in both the sequential (P=0.058) and concurrent (P=0.0018) chemoimmunotherapy arms. Respectively, 5 of 10 and 9 of 20 patients had a positive immune response but there was no association with apoptosis. Conclusions: Combination gemcitabine and capecitabine chemotherapy did not affect circulating levels of GM-CSF, IL-6 and CRP. Chemotherapy-induced apoptosis was not associated with the immunogenicity induced by the GV1001 vaccine in advanced pancreatic cancer

    The Effect of Particulate Air Pollution on Emergency Admissions for Myocardial Infarction: A Multicity Case-Crossover Analysis

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    Recently, attention has focused on whether particulate air pollution is a specific trigger of myocardial infarction (MI). The results of several studies of single locations assessing the effects of ambient particular matter on the risk of MI have been disparate. We used a multicity case-crossover study to examine risk of emergency hospitalization associated with fine particulate matter (PM) with aerodynamic diameter < 10 μm (PM(10)) for > 300,000 MIs during 1985–1999 among elderly residents of 21 U.S. cities. We used time-stratified controls matched on day of the week or on temperature to detect possible residual confounding by weather. Overall, we found a 0.65% [95% confidence interval (CI), 0.3–1.0%] increased risk of hospitalization for MI per 10 μg/m(3) increase in ambient PM(10) concentration. Matching on apparent temperature yielded a 0.64% increase in risk (95% CI, 0.1–1.2%). We found that the effect size for PM(10) doubled for subjects with a previous admission for chronic obstructive pulmonary disease or a secondary diagnosis of pneumonia, although these differences did not achieve statistical significance. There was a weaker indication of a larger effect on males but no evidence of effect modification by age or the other diagnoses. We also found that the shape of the exposure–response relationship between MI hospitalizations and PM(10) is almost linear, but with a steeper slope at levels of PM(10) < 50 μg/m(3). We conclude that increased concentrations of ambient PM(10) are associated with increased risk of MI among the elderly

    Insulin-like growth factor 2 mRNA binding protein 3 (IGF2BP3) overexpression in pancreatic ductal adenocarcinoma correlates with poor survival

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    <p>Abstract</p> <p>Background</p> <p>Pancreatic ductal adenocarcinoma is a lethal disease with a 5-year survival rate of 4% and typically presents in an advanced stage. In this setting, prognostic markers identifying the more agrressive tumors could aid in managment decisions. Insulin-like growth factor 2 mRNA binding protein 3 (IGF2BP3, also known as IMP3 or KOC) is an oncofetal RNA-binding protein that regulates targets such as insulin-like growth factor-2 (IGF-2) and ACTB (beta-actin).</p> <p>Methods</p> <p>We evaluated the expression of IGF2BP3 by immunohistochemistry using a tissue microarray of 127 pancreatic ductal adenocarcinomas with tumor grade 1, 2 and 3 according to WHO criteria, and the prognostic value of IGF2BP3 expression.</p> <p>Results</p> <p>IGF2BP3 was found to be selectively overexpressed in pancreatic ductal adenocarcinoma tissues but not in benign pancreatic tissues. Nine (38%) patient samples of tumor grade 1 (n = 24) and 27 (44%) of tumor grade 2 (n = 61) showed expression of IGF2BP3. The highest rate of expression was seen in poorly differentiated specimen (grade 3, n = 42) with 26 (62%) positive samples. Overall survival was found to be significantly shorter in patients with IGF2BP3 expressing tumors (P = 0.024; RR 2.3, 95% CI 1.2-4.8).</p> <p>Conclusions</p> <p>Our data suggest that IGF2BP3 overexpression identifies a subset of pancreatic ductal adenocarcinomas with an extremely poor outcome and supports the rationale for developing therapies to target the IGF pathway in this cancer.</p

    Repetition and severity of suicide attempts across the life cycle: a comparison by age group between suicide victims and controls with severe depression

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    <p>Abstract</p> <p>Background</p> <p>Suicide attempts have been shown to be less common in older age groups, with repeated attempts generally being more common in younger age groups and severe attempts in older age groups. Consistently, most studies have shown an increased suicide risk after attempts in older age. However, little is known about the predictive value of age on repeated and severe suicide attempts for accomplished suicide. The aim of the present study was to investigate the reduced incidence for initial, repeated, or severe suicide attempts with age in suicide victims and controls by gender.</p> <p>Methods</p> <p>The records of 100 suicide victims and matched controls with severe depression admitted to the Department of Psychiatry, Lund University Hospital, Sweden between 1956 and 1969, were evaluated and the subjects were monitored up to 2006. The occurrence of suicide attempts (first, repeated, or severe, by age group) was analysed for suicide victims and controls, with gender taken into consideration.</p> <p>Results</p> <p>There was a reduced risk for an initial suicide attempt by older age in females (suicide victims and controls) and male controls (but not suicide victims). The risk for repeated suicide attempts appeared to be reduced in the older age groups in female controls as compared to female suicide victims. The risk for severe suicide attempts seemed reduced in the older age groups in female suicide victims. This risk was also reduced in male controls and in male controls compared to male suicide victims.</p> <p>Conclusion</p> <p>In the older age groups repeated attempts appeared to be predictive for suicide in women and severe attempts predictive in men.</p

    CDK1 is a synthetic lethal target for KRAS mutant tumours.

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    Activating KRAS mutations are found in approximately 20% of human cancers but no RAS-directed therapies are currently available. Here we describe a novel, robust, KRAS synthetic lethal interaction with the cyclin dependent kinase, CDK1. This was discovered using parallel siRNA screens in KRAS mutant and wild type colorectal isogenic tumour cells and subsequently validated in a genetically diverse panel of 26 colorectal and pancreatic tumour cell models. This established that the KRAS/CDK1 synthetic lethality applies in tumour cells with either amino acid position 12 (p.G12V, pG12D, p.G12S) or amino acid position 13 (p.G13D) KRAS mutations and can also be replicated in vivo in a xenograft model using a small molecule CDK1 inhibitor. Mechanistically, CDK1 inhibition caused a reduction in the S-phase fraction of KRAS mutant cells, an effect also characterised by modulation of Rb, a master control of the G1/S checkpoint. Taken together, these observations suggest that the KRAS/CDK1 interaction is a robust synthetic lethal effect worthy of further investigation

    MRI of Arterial Flow Reserve in Patients with Intermittent Claudication: Feasibility and Initial Experience

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    Objectives: The aim of this work was to develop a MRI method to determine arterial flow reserve in patients with intermittent claudication and to investigate whether this method can discriminate between patients and healthy control subjects. Methods: Ten consecutive patients with intermittent claudication and 10 healthy control subjects were included. All subjects underwent vector cardiography triggered quantitative 2D cine MR phase-contrast imaging to obtain flow waveforms of the popliteal artery at rest and during reactive hyperemia. Resting flow, maximum hyperemic flow and absolute flow reserve were determined and compared between the two groups by two independent MRI readers. Also, interreader reproducibility of flow measures was reported. Results: Resting flow was lower in patients compared to controls (4.961.6 and 11.163.2 mL/s in patients and controls, respectively (p,0.01)). Maximum hyperemic flow was 7.362.9 and 16.463.2 mL/s (p,0.01) and the absolute flow reserve was 2.461.6 and 5.361.3 mL/s (p,0.01), respectively in patients and controls. The interreader coefficient of variation was below 10 % for all measures in both patients and controls. Conclusions: Quantitative 2D MR cine phase-contrast imaging is a promising method to determine flow reserve measures in patients with peripheral arterial disease and can be helpful to discriminate patients with intermittent claudication fro
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