2,842 research outputs found

    Harnessing autophagy to overcome mitogen‐activated protein kinase kinase inhibitor‐induced resistance in metastatic melanoma

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    Background Patients with malignant melanoma often relapse after treatment with BRAF and/or mitogen‐activated protein kinase kinase (MEK) inhibitors (MEKi) owing to development of drug resistance. Objectives To establish the temporal pattern of CD271 regulation during development of resistance by melanoma to trametinib, and determine the association between development of resistance to trametinib and induction of prosurvival autophagy. Methods Immunohistochemistry for CD271 and p62 was performed on human naevi and primary malignant melanoma tumours. Western blotting was used to analyse expression of CD271, p62 and LC3 in melanoma subpopulations. Flow cytometry and immunofluorescence microscopy was used to evaluate trametinib‐induced cell death and CD271 expression. MTS viability assays and zebrafish xenografts were used to evaluate the effect of CD271 and autophagy modulation on trametinib‐resistant melanoma cell survival and invasion, respectively. Results CD271 and autophagic signalling are increased in stage III primary melanomas vs. benign naevi. In vitro studies demonstrate MEKi of BRAF‐mutant melanoma induced cytotoxic autophagy, followed by the emergence of CD271‐expressing subpopulations. Trametinib‐induced CD271 reduced autophagic flux, leading to activation of prosurvival autophagy and development of MEKi resistance. Treatment of CD271‐expressing melanoma subpopulations with RNA interference and small‐molecule inhibitors to CD271 reduced the development of MEKi resistance, while clinically applicable autophagy modulatory agents – including Δ9‐tetrahydrocannabinol and Vps34 – reduced survival of MEKi‐resistant melanoma cells. Combined MEK/autophagy inhibition also reduced the invasive and metastatic potential of MEKi‐resistant cells in an in vivo zebrafish xenograft. Conclusions These results highlight a novel mechanism of MEKi‐induced drug resistance and suggest that targeting autophagy may be a translatable approach to resensitize drug‐resistant melanoma cells to the cytotoxic effects of MEKi

    A feasibility study of signed consent for the collection of patient identifiable information for a national paediatric clinical audit database

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    Objectives: To investigate the feasibility of obtaining signed consent for submission of patient identifiable data to a national clinical audit database and to identify factors influencing the consent process and its success. Design: Feasibility study. Setting: Seven paediatric intensive care units in England. Participants: Parents/guardians of patients, or patients aged 12-16 years old, approached consecutively over three months for signed consent for submission of patient identifiable data to the national clinical audit database the Paediatric Intensive Care Audit Network (PICANet). Main outcome measures: The numbers and proportions of admissions for which signed consent was given, refused, or not obtained (form not returned or form partially completed but not signed), by age, sex, level of deprivation, ethnicity (South Asian or not), paediatric index of mortality score, length of hospital stay (days in paediatric intensive care). Results: One unit did not start and one did not fully implement the protocol, so analysis excluded these two units. Consent was obtained for 182 of 422 admissions (43%) (range by unit 9% to 84%). Most (101/182; 55%) consents were taken by staff nurses. One refusal (0.2%) was received. Consent rates were significantly better for children who were more severely ill on admission and for hospital stays of six days or more, and significantly poorer for children aged 10-14 years. Long hospital stays and children aged 10-14 years remained significant in a stepwise regression model of the factors that were significant in the univariate model. Conclusion: Systematically obtaining individual signed consent for sharing patient identifiable information with an externally located clinical audit database is difficult. Obtaining such consent is unlikely to be successful unless additional resources are specifically allocated to training, staff time, and administrative support

    Perioperative Teaching and Feedback: How are we doing in Canadian OTL-HNS programs?

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    Background: Discrepancies between resident and faculty perceptions regarding optimal teaching and feedback during surgery are well known but these differences have not yet been described in Otolaryngology - Head and Neck Surgery (OTL-HNS). The objectives were thus to compare faculty and resident perceptions of perioperative teaching and feedback in OTL-HNS residency programs across Canada with the aim of highlighting potential areas for improvement. Methods: An anonymous electronic questionnaire was distributed to residents and teaching faculty in OTL-HNS across Canada with additional paper copies distributed at four institutions. Surveys consisted of ratings on a 5-point Likert scale and open-ended questions. Responses among groups were analysed with the Wilcoxon-Mann Whitney test, while thematic analysis was used for the open-ended questions. Results: A total of 143 teaching faculty and residents responded with statistically significant differences on 11 out of 25 variables. Namely, faculty reported higher rates of pre and intra-operative teaching compared to resident reports. Faculty also felt they gave adequate feedback on residents\u27 strengths and technical skills contrary to what the residents thought. Both groups did agree however that pre-operative discussion is not consistently done, nor is feedback consistently given or sought. Conclusion: Faculty and residents in OTL-HNS residency programs disagree on the frequency and optimal timing of peri-operative teaching and feedback. This difference in perception emphasizes the need for a more structured approach to feedback delivery including explicitly stating when feedback is being given, and the overall need for better communication between residents and staff

    Somatization among ethnic minorities and immigrants: Why does it matter to Consultation Liaison Psychiatry?

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    The article describes the reasons why psychiatrists working in the field of consultation-liaison should be trained and aware of the relevance of culture in their everyday work. Moreover, the article aims at advertising the special-interest group on cultural CLP, a network of clinicians and researchers within the European Association of Psychosomatic Medicine that share their interest and activities in this subject

    Histopathological changes and antioxidant responses in common carp (Cyprinus carpio) exposed to copper nanoparticles

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    This is the author accepted manuscript. The final version is available from Taylor & Francis via the DOI in this recordDespite the rapid increase of nanotechnology in a wide array of industrial sectors, the biosafety profile of nanomaterials remains undefined. The accelerated use of nanomaterials has increased the potential discharge of nanomaterials into the environment in different ways. The aquatic environment is mainly susceptible as it is likely to act as an ultimate sink for all contaminants. Therefore, this study assessed the toxicological impacts of waterborne engineered copper nanoparticles (Cu-NPs) on histology, lipid peroxidation (LPO), catalase (CAT), and glutathione (GSH) levels in the gills of common carp (Cyprinus carpio). Nanoparticles were characterized by XRD and SEM techniques. Before starting the sub-acute toxicity testing, 96 h LC50 of Cu-NPs for C. carpio was calculated as 4.44 mg/l. Then based on LC50, C. carpio of 40–45 g in weight were exposed to three sub-lethal doses of waterborne engineered Cu-NPs (0 or 0.5 or 1 or 1.5 mg/l) for a period of 14 days. The waterborne Cu-NPs have appeared to induce alterations in gill histology and oxidative stress parameters in a dose-dependent manner. The gill tissues showed degenerative secondary lamellae, necrotic lamella, fused lamella, necrosis of the primary and secondary lamella, edema, complete degeneration, epithelial lifting, degenerative epithelium, and hyperplasia in a dose-dependent manner. In the gill tissues, waterborne Cu-NPs caused a decreased level of CAT and elevated levels of LPO, and GSH in the fish exposed to the highest dose of 1.5 mg Cu-NPs/l of water. Our results indicate that the exposure to waterborne Cu-NPs was toxic to the aquatic organisms as shown by the oxidative stresses and histological alterations in C. carpio, a freshwater fish of good economic value
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