265 research outputs found

    Tumour budding and poorly differentiated clusters in colon cancer – different manifestations of partial epithelial-mesenchymal transition

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    Morphological features including infiltrative growth, tumour budding (TB) and poorly differentiated clusters (PDCs), have a firmly established negative predictive value in colorectal cancer (CRC). Despite extensive research, the mechanisms underlying different tumour growth patterns remain poorly understood. The aim of this study was to investigate the involvement of epithelial-mesenchymal transition (EMT) in TB and PDCs in CRC. Using laser-capture microdissection, we obtained distinct parts of the primary CRC including TB, PDCs, expansive tumour front and the central part of the tumour and analysed the expression of EMT-related markers, i.e., miR-200 family, ZEB1/2, RND3 and CDH1. In TB, the miR-200 family and CDH1 were significantly downregulated, while ZEB2 was significantly upregulated. In PDCs, miR- 141, miR-200c and CDH1 were significantly downregulated. No significant differences were observed in the expression of any EMT-related markers between the expansive tumour front and the central part of the tumour. Our results suggest that both TB and PDCs are related to partial EMT. Discrete differences in morphology and EMT-related markers expression between TB and PDCs indicate that they represent different manifestations of partial EMT. TB seems to be closer to complete EMT than PDCs

    Improvement of conventional anti-cancer drugs as new tools against multidrug resistant tumors

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    Multidrug resistance (MDR) is the dominant cause of the failure of cancer chemotherapy. The design of antitumor drugs that are able to evade MDR is rapidly evolving, showing that this area of biomedical research attracts great interest in the scientific community. The current review explores promising recent approaches that have been developed with the aim of circumventing or overcoming MDR. Encouraging results have been obtained in the investigation of the MDR-modulating properties of various classes of natural compounds and their analogues. Inhibition of P-gp or downregulation of its expression have proven to be the main mechanisms by which MDR can be surmounted. The use of hybrid molecules that are able to simultaneously interact with two or more cancer cell targets is currently being explored as a means to circumvent drug resistance. This strategy is based on the design of hybrid compounds that are obtained either by merging the structural features of separate drugs, or by conjugating two drugs or pharmacophores via cleavable/non-cleavable linkers. The approach is highly promising due to the pharmacokinetic and pharmacodynamic advantages that can be achieved over the independent administration of the two individual components. However, it should be stressed that the task of obtaining successful multivalent drugs is a very challenging one. The conjugation of anticancer agents with nitric oxide (NO) donors has recently been developed, creating a particular class of hybrid that can combat tumor drug resistance. Appropriate NO donors have been shown to reverse drug resistance via nitration of ABC transporters and by interfering with a number of metabolic enzymes and signaling pathways. In fact, hybrid compounds that are produced by covalently attaching NO-donors and antitumor drugs have been shown to elicit a synergistic cytotoxic effect in a variety of drug resistant cancer cell lines. Another strategy to circumvent MDR is based on nanocarrier-mediated transport and the controlled release of chemotherapeutic drugs and P-gp inhibitors. Their pharmacokinetics are governed by the nanoparticle or polymer carrier and make use of the enhanced permeation and retention (EPR) effect, which can increase selective delivery to cancer cells. These systems are usually internalized by cancer cells via endocytosis and accumulate in endosomes and lysosomes, thus preventing rapid efflux. Other modalities to combat MDR are described in this review, including the pharmaco-modulation of acridine, which is a well-known scaffold in the development of bioactive compounds, the use of natural compounds as means to reverse MDR, and the conjugation of anticancer drugs with carriers that target specific tumor-cell components. Finally, the outstanding potential of in silico structure-based methods as a means to evaluate the ability of antitumor drugs to interact with drug transporters is also highlighted in this review. Structure-based design methods, which utilize 3D structural data of proteins and their complexes with ligands, are the most effective of the in silico methods available, as they provide a prediction regarding the interaction between transport proteins and their substrates and inhibitors. The recently resolved X-ray structure of human P-gp can help predict the interaction sites of designed compounds, providing insight into their binding mode and directing possible rational modifications to prevent them from becoming P-gp drug substrates. In summary, although major efforts were invested in the search for new tools to combat drug resistant tumors, they all require further implementation and methodological development. Further investigation and progress in the abovementioned strategies will provide significant advances in the rational combat against cancer MDR

    918-7 Limitations of Percutaneous Interventions in the Treatment of Bifurcation Lesions Involving the Left Anterior Descending Coronary Artery

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    Serious complications may occur when intervention is unsuccessful in bifurcation lesions involving the left anterior descending (LAD) and first major diagonal (D), because of the large amount of involved myocardium. To determine this complication rate, we reviewed 82 consecutive cases, over a 3 year period, in which these lesions were attempted. Sixty-six percent of the subjects were male, and 37% had unstable angina. The mean age was 59 and the mean ejection fraction was 56%. Digital calipers were used to measure vessel minimum lumen (MLD) and reference diameters. For the LAD the final MLD was 1.81mm and for the 0 1.32mm. The final percent mean diameter stenoses for the LAD and D were 41% and 45%, respectively. There were no significant differences in the rates of success or complication between groups treated with angioplasty only (N=68) or directional atherectomy (N=14). The in-hospital event-free success rate was 55%. The in-hospital complication rates were:Recurrent Ischemia16%Ventricular Tachycardia2%Myocardial Infarction14%Stroke2%Bypass Surgery12%Death1%Repeat Procedure4%Composite34%ConclusionLAD bifurcation lesion intervention is associated with a high in-hospital complication rate. Since these lesions are not amenable to stent placement or atherectomy with simultaneous protection of both vessels, these cases should be carefully evaluated before intervention, and bypass surgery should be considered as a treatment option

    In-beam internal conversion electron spectroscopy with the SPICE detector

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    The SPectrometer for Internal Conversion Electrons (SPICE) has been commissioned for use in conjunction with the TIGRESS Îł\gamma-ray spectrometer at TRIUMF's ISAC-II facility. SPICE features a permanent rare-earth magnetic lens to collect and direct internal conversion electrons emitted from nuclear reactions to a thick, highly segmented, lithium-drifted silicon detector. This arrangement, combined with TIGRESS, enables in-beam Îł\gamma-ray and internal conversion electron spectroscopy to be performed with stable and radioactive ion beams. Technical aspects of the device, capabilities, and initial performance are presented

    Pharmacological manipulations of judgement bias:a systematic review and meta-analysis

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    Validated measures of animal affect are crucial to research spanning numerous disciplines. Judgement bias, which assesses decision-making under ambiguity, is a promising measure of animal affect. One way of validating this measure is to administer drugs with affect-altering properties in humans to non-human animals and determine whether the predicted judgement biases are observed. We conducted a systematic review and meta-analysis using data from 20 published research articles that use this approach, from which 557 effect sizes were extracted. Pharmacological manipulations overall altered judgement bias at the probe cues as predicted. However, there were several moderating factors including the neurobiological target of the drug, whether the drug induced a relatively positive or negative affective state in humans, dosage, and the presented cue. This may partially reflect interference from adverse effects of the drug which should be considered when interpreting results. Thus, the overall pattern of change in animal judgement bias appears to reflect the affect-altering properties of drugs in humans, and hence may be a valuable measure of animal affective valence.Funding Agencies|Biotechnology and Biological Sciences Research Council (BBSRC: SWBio Doctoral Training Programme)Biotechnology and Biological Sciences Research Council (BBSRC) [BB/M009122/1]; Australian Research Council (ARC)Australian Research Council [DP180100818]</p

    Coupling of conductive, convective and radiative heat transfer in Czochralski crystal growth process

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    Abstract This paper studies the conjugate problems of fluid flow and energy transport (involving conduction, convection and radiation heat transfer) within a material changing its phase. The analysis focuses on the Czochralski crystal growth process. The solidifying material is treated as a pure substance with constant material properties. The solution of the resulting 3-D, axisymmetric, non-linear problem is obtained iteratively using the commercial CFD package Fluent. The algorithm employed here treats each subdomain of the system separately, i.e. the liquid and solid phases of the solidified material, as well as the inertial gas surrounding both phases. Results of a test case shows the velocity field and temperature distribution within a simple system employed for the growth of a single silicon crystal
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