191 research outputs found

    Letters

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    Ovarian Cancer Genetics: Subtypes and Risk Factors

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    The genetics of ovarian cancer are a complex, ever evolving concept that presents hurdles in classification, diagnosis, and treatment in the clinic. Instead of common driver mutations, genomic instability is one of the hallmarks of ovarian cancer. While ovarian cancer is stratified into different clinical subtypes, there still exists extensive genetic and progressive diversity within each subtype. In high-grade serous ovarian cancer, the most common subtype, TP53 is mutated in over 90% of all patients while the next most common mutation is less than 20%. However, next-generation sequencing and biological statistics have shown that mutations within DNA repair pathways, including BRCA1 and BRCA2, are common in about 50% of all high-grade serous patients leading to the development of a breakthrough therapy of poly ADP ribose polymerase (PARP) inhibitors. This is just one example of how a better understanding of the complex genetic background of ovarian cancer can improve clinical treatment. A thorough review of ovarian cancer genetics and the effect it has on disease development, diagnosis, progression, and treatment will enhance the understanding of how to better research and treat ovarian cancer

    Tumor-Derived Exosomes Mediate Platinum Resistance in Ovarian Cancer Through Regulation of EMT

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    Nano-sized vesicles, termed exosomes, have been implicated in the transfer of oncogenic proteins and genetic material from one cell to another. We speculated this may be one mechanism by which an intrinsically platinum-resistant population of epithelial ovarian cancer (EOC) cells imparts its influence on surrounding tumor cells. To explore this possibility we have utilized the platinum-sensitive A2780 cell line and independent platinum-resistant derivatives, e.g., CP70 and C30, as well as a non-related platinum-resistant cell line, OVCAR10. We find A2780 cells treated with exosomes derived from highly resistant cells demonstrate up to a ~2-fold increase (p<0.05) in resistance to carboplatin as compared to treatment with isolated autologous exosomes. Importantly, this exosome-associated phenotype is stable and associated with increased epithelial to mesenchymal transition (EMT) characteristics. In addition, we identified previously unreported somatic mutations in the Mothers Against Decapentaplegic Homolog 4 (SMAD4), only in cells (OVCAR10, C30, and CP70) that demonstrated robust acquired resistance after platinum therapy. Cells displaying mutations in SMAD4 exhibited significant changes in EMT-related markers following treatment with carboplatin. Interestingly, exosomes derived from A2780 cells engineered to exogenously express specific SMAD4 mutations resulted in ~1.7-fold (p<0.05) increase in resistance as compared to exosomes isolated from exogenous wildtype SMAD4 (SMAD4WT) expressing A2780 cells, suggesting these mutations are contributing to the development of a resistant phenotype. Additionally, cells expressing mutations in SMAD4 exhibit a loss of phosphorylation of SMAD2 but retain activated SMAD3, which is important for EMT. Importantly, inhibition of SMAD3 via the small molecule inhibitor, SIS3, reversed the EMT phenotype and acted synergistically with carboplatin to enhance cell death. Lastly, we identified a clinically relevant inhibitor of SMAD3, Eribulin Mesylate (Halaven®), which also acted synergistically with carboplatin in vitro. Altogether, our findings provide the first evidence that ovarian tumor cells use exosomes as a vehicle to achieve tumor cell-cell crosstalk and this exchange advantageously impacts the recipient cells response to platinum. We continue to describe a novel mechanism of action by which an EMT phenotype is perpetuated via exchange of tumor-derived exosomes, ultimately leading to the development of a subpopulation of chemotherapy refractory cells. Importantly, we present a novel therapeutic strategy that targets resistant cells and ‘tricks’ them into responding once again to the most effective therapeutics to date, cisplatin and carboplatin

    Do marine protected areas affect emerging fisheries population density?

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    Kellet’s whelk, Kelletia kelletii, were observed at sample sites throughout their range from Baja California, Mexico, to Monterey, CA to determine patterns of population density. Sample sites in each region were either located within California marine protected areas where take of the Kellet’s whelk in prohibited, or in non-protected areas where the whelks can be fished both commercially and recreationally. Kellet’s whelk population density was compared between all MPA and non-MPA sample sites. These mean densities were also found for sites in Santa Barbara and San Diego near active fishing ports and compared to data from the same sites collected in 2004. Whelk density was significantly greater in MPAs than in non-MPA sample sites. Moreover, the comparison of MPA and non-MPA sites near fishing ports between 2004 and 2015 data showed non-significant changes in density over the 11 years, but there were noticeable trends in decreasing density in the fished areas while the density in the MPAs remained fairly constant. Our results suggest that fishing pressure has caused a decreased density of Kellet’s whelk in fished areas, while these effects have been mitigated in protected areas. Significant decreases in density of the Kellet’s whelk could alter kelp forest population dynamics, and although the overall population is currently stable, consumers must be aware of overfishing

    Integrated immunoisolation and protein analysis of circulating exosomes using microfluidic technology

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    Developing blood-based tests is appealing for non-invasive disease diagnosis, especially when biopsy is difficult, costly, and sometimes not even an option. Tumor-derived exosomes have attracted increasing interest in non-invasive cancer diagnosis and monitoring of treatment response. However, the biology and clinical value of exosomes remains largely unknown due in part to current technical challenges in rapid isolation, molecular classification and comprehensive analysis of exosomes. Here we developed a new microfluidic approach to streamline and expedite the exosome analysis pipeline by integrating specific immunoisolation and targeted protein analysis of circulating exosomes. Compared to the conventional methods, our approach enables selective subpopulation isolation and quantitative detection of surface and intravesicular biomarkers directly from a minimally invasive amount of plasma samples (30 μL) within ~100 min with markedly improved detection sensitivity. Using this device, we demonstrated phenotyping of exosome subpopulations by targeting a panel of common exosomal and tumor-specific markers and multiparameter analyses of intravesicular biomarkers in the selected subpopulation. We were able to assess the total expression and phosphorylation levels of IGF-1R in non-small-cell lung cancer patients by probing plasma exosomes as a non-invasive alternative to conventional tissue biopsy. We foresee that the microfluidic exosome analysis platform will form the basis for critically needed infrastructures for advancing the biology and clinical utilization of exosomes

    Renewing Teaching Practices: Differentiated Instruction in the College Classroom

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    At a time of high college student attrition rates, faculty who work in higher education settings are being challenged more than ever before with accountability for student learning. The purpose of this article is to share insights relative to a multi-year professional development initiative that provided college faculty with an opportunity to explore changes in their teaching. Over the course of three years, faculty members honed their knowledge, skills, and dispositions relative to a specific instructional strategy for their own classrooms: differentiated instruction. An experiential approach to the initiative was used, and the degree to which participants committed to change their own instructional practices was evaluated. Results indicated an encouraging degree of success, especially in technology integration, providing clear objectives and feedback to students, and enhanced student engagement

    A checklist for clinical trials in rare disease: Obstacles and anticipatory actions-lessons learned from the FOR-DMD trial

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    Background: Trials in rare diseases have many challenges, among which are the need to set up multiple sites in different countries to achieve recruitment targets and the divergent landscape of clinical trial regulations in those countries. Over the past years, there have been initiatives to facilitate the process of international study set-up, but the fruits of these deliberations require time to be operationally in place. FOR-DMD (Finding the Optimum Steroid Regimen for Duchenne Muscular Dystrophy) is an academic-led clinical trial which aims to find the optimum steroid regimen for Duchenne muscular dystrophy, funded by the National Institutes of Health (NIH) for 5 years (July 2010 to June 2015), anticipating that all sites (40 across the USA, Canada, the UK, Germany and Italy) would be open to recruitment from July 2011. However, study start-up was significantly delayed and recruitment did not start until January 2013. Method: The FOR-DMD study is used as an example to identify systematic problems in the set-up of international, multi-centre clinical trials. The full timeline of the FOR-DMD study, from funding approval to site activation, was collated and reviewed. Systematic issues were identified and grouped into (1) study set-up, e.g. drug procurement; (2) country set-up, e.g. competent authority applications; and (3) site set-up, e.g. contracts, to identify the main causes of delay and suggest areas where anticipatory action could overcome these obstacles in future studies. Results: Time from the first contact to site activation across countries ranged from 6 to 24 months. Reasons of delay were universal (sponsor agreement, drug procurement, budgetary constraints), country specific (complexity and diversity of regulatory processes, indemnity requirements) and site specific (contracting and approvals). The main identified obstacles included (1) issues related to drug supply, (2) NIH requirements regarding contracting with non-US sites, (3) differing regulatory requirements in the five participating countries, (4) lack of national harmonisation with contracting and the requirement to negotiate terms and contract individually with each site and (5) diversity of languages needed for study materials. Additionally, as with many academic-led studies, the FOR-DMD study did not have access to the infrastructure and expertise that a contracted research organisation could provide, organisations often employed in pharmaceutical-sponsored studies. This delay impacted recruitment, challenged the clinical relevance of the study outcomes and potentially delayed the delivery of the best treatment to patients. Conclusion: Based on the FOR-DMD experience, and as an interim solution, we have devised a checklist of steps to not only anticipate and minimise delays in academic international trial initiation but also identify obstacles that will require a concerted effort on the part of many stakeholders to mitigate

    Reproducibility of left atrial ablation with high-intensity focused ultrasound energy in a calf model

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    ObjectiveAchieving transmural tissue ablation might be necessary for successful treatment of atrial fibrillation. The purpose of this study was to evaluate the reproducibility of transmural left atrial ablation using a high-intensity focused ultrasound energy system in a calf model.MethodsNine heparinized bovines underwent a beating-heart left atrial ablation with a single application of the high-intensity focused ultrasound device. All animals were acutely killed, and the left atrium was fixed in formalin. Protocolized histological sections (5 μm) were obtained throughout each lesion and prepared with Masson trichrome and hematoxylin and eosin staining. Measurements were performed on a total of 359 slides from the 9 lesions. In addition, fresh left atrial tissues from 18 unused human donor hearts that did not meet the criteria for cardiac transplantation were measured at the site where the high-intensity focused ultrasound device is normally applied.ResultsCalf left atrial thickness ranged between 2.5 and 20.1 mm, with a mean of 9.10 mm. High-intensity focused ultrasound ablation consistently produced a 100% transmural lesion in left atrial thickness up to 6 mm. In addition, a transmural lesion was observed in 91% of tissues that were up to 10 mm thick and in 85% that were up to 15 mm thick. Human left atrial thickness ranged between 1.2 to 6 mm, with a mean of 3.7 mm.ConclusionsCalf left atrial thickness in this study was greater than human left atrial thickness. Human left atrial thickness is generally less than 6 mm, and in this range high-intensity focused ultrasound ablation achieved 100% transmurality. These histological results might correlate with a high success rate of atrial fibrillation ablation by using the high-intensity focused ultrasound system

    Visual Ethics: developing good practice

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    This project aimed to capitalise on the NCRM’s networks and innovative work in visual methods to i) identify visual researchers’ everyday practice in relation to ethics; ii) map the ethical issues and challenges encountered by visual researchers ; iii) identify the strategies adopted to manage visual ethics; iv) gain an understanding, and identify exemplars, of good ethical practice in visual research; v) identify any particularly problematic or seemingly ‘unresolvable’ ethical concerns that would benefit from further and more detailed exploration. It was intended that a resource on good ethical practice for visual researchers would be developed from the project
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