248 research outputs found

    A training programme to build cancer research capacity in low- and middle-income countries: Findings from Guatemala

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    PROBLEM: Guatemala is experiencing an increasing burden of cancer but lacks capacity for cancer prevention, control and research. APPROACH: In partnership with a medical school in the United States of America, a multidisciplinary Cancer Control Research Training Institute was developed at the Instituto de Cancerología (INCAN) in Guatemala City. This institute provided a year-long training programme for clinicians that focused on research methods in population health and sociocultural anthropology. The programme included didactic experiences in Guatemala and the United States as well as applied training in which participants developed research protocols responsive to Guatemala\u27s cancer needs. LOCAL SETTING: Although INCAN is the point of referral and service for Guatemala\u27s cancer patients, the institute\u27s administration is also interested in increasing cancer research - with a focus on population health. INCAN is thus a resource for capacity building within the context of cancer prevention and control. RELEVANT CHANGES: Trainees increased their self-efficacy for the design and conduct of research. Value-added benefits included establishment of an annual cancer seminar and workshops in cancer pathology and qualitative analysis. INCAN has recently incorporated some of the programme\u27s components into its residency training and established a research department. LESSONS LEARNT: A training programme for clinicians can build cancer research capacity in low- and middle-income countries. Training in population-based research methods will enable countries such as Guatemala to gather country-specific data. Once collected, such data can be used to assess the burden of cancer-related disease, guide policy for reducing it and identify priority areas for cancer prevention and treatment

    Focal Segmental Glomerulosclerosis Complicating Therapy With Inotersen, an Antisense Oligonucleotide Inhibitor: A Case Report

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    Inotersen is an antisense oligonucleotide inhibitor licensed for the treatment of polyneuropathy complicating hereditary transthyretin amyloidosis (ATTRv). Nephrotoxicity has been reported with inotersen, including progression to end stage renal disease. We describe the first reported case of inotersen-associated nephrotic syndrome secondary to focal segmental glomerulosclerosis (FSGS) and review the literature concerning inotersen-induced nephrotoxicity. We report a woman in her early 30s with ATTRv associated with the (p.V50M) transthyretin (TTR) variant, who presented with nephrotic syndrome 7 months after commencement of inotersen. Renal histology demonstrated focal segmental glomerulosclerosis and scanty glomerular amyloid deposition. Discontinuation of inotersen alone resulted in complete clinical and biochemical resolution of nephrotic syndrome. Inotersen is associated with significant nephrotoxicity. In the phase III NEURO-TTR clinical trial, 3% of patients in the treatment arm developed a crescentic glomerulonephritis. All affected patients carried the (p.V50M) TTR variant which is known to be associated with renal amyloid deposition. This case adds to spectrum of renal disease associated with inotersen and indicates that discontinuation of the drug alone may result in resolution of renal complications without additional immunosuppression. Monitoring of renal function is essential in patients with ATTRv receiving inotersen, particularly if there is evidence of existing renal amyloid

    K2-136: A Binary System in the Hyades Cluster Hosting a Neptune-sized Planet

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    We report the discovery of a Neptune-size planet (R_p = 3.0 R⊕) in the Hyades Cluster. The host star is in a binary system, comprising a K5V star and M7/8V star with a projected separation of 40 au. The planet orbits the primary star with an orbital period of 17.3 days and a transit duration of 3 hrs. The host star is bright (V = 11.2, J = 9.1) and so may be a good target for precise radial velocity measurements. K2-136A c is the first Neptune-sized planet to be found orbiting in a binary system within an open cluster. The Hyades is the nearest star cluster to the Sun, has an age of 625–750 Myr, and forms one of the fundamental rungs in the distance ladder; understanding the planet population in such a well-studied cluster can help us understand and set constraints on the formation and evolution of planetary systems

    Characterizing K2 Candidate Planetary Systems Orbiting Low-mass Stars. IV. Updated Properties for 86 Cool Dwarfs Observed during Campaigns 1–17

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    We present revised stellar properties for 172 K2 target stars that were identified as possible hosts of transiting planets during Campaigns 1–17. Using medium-resolution near-infrared spectra acquired with the NASA Infrared Telescope Facility/SpeX and Palomar/TripleSpec, we found that 86 of our targets were bona fide cool dwarfs, 74 were hotter dwarfs, and 12 were giants. Combining our spectroscopic metallicities with Gaia parallaxes and archival photometry, we derived photometric stellar parameters and compared them to our spectroscopic estimates. Although our spectroscopic and photometric radius and temperature estimates are consistent, our photometric mass estimates are systematically ΔM sstarf = 0.11 M ⊙ (34%) higher than our spectroscopic mass estimates for the least massive stars (M sstarf,phot < 0.4 M ⊙). Adopting the photometric parameters and comparing our results to parameters reported in the Ecliptic Plane Input Catalog, our revised stellar radii are ΔR sstarf = 0.15 R ⊙ (40%) larger, and our revised stellar effective temperatures are roughly ΔT eff = 65 K cooler. Correctly determining the properties of K2 target stars is essential for characterizing any associated planet candidates, estimating the planet search sensitivity, and calculating planet occurrence rates. Even though Gaia parallaxes have increased the power of photometric surveys, spectroscopic characterization remains essential for determining stellar metallicities and investigating correlations between stellar metallicity and planetary properties

    K2-288Bb: A Small Temperate Planet in a Low-mass Binary System Discovered by Citizen Scientists

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    Original content from this work may be used under the terms of the Creative Commons Attribution 3.0 licence. Any further distribution of this work must maintain attribution to the author(s) and the title of the work, journal citation and DOI.Observations from the Kepler and K2 missions have provided the astronomical community with unprecedented amounts of data to search for transiting exoplanets and other astrophysical phenomena. Here, we present K2-288, a low-mass binary system (M2.0 ± 1.0; M3.0 ± 1.0) hosting a small (R p = 1.9 R ⊕), temperate (T eq = 226 K) planet observed in K2 Campaign 4. The candidate was first identified by citizen scientists using Exoplanet Explorers hosted on the Zooniverse platform. Follow-up observations and detailed analyses validate the planet and indicate that it likely orbits the secondary star on a 31.39-day period. This orbit places K2-288Bb in or near the habitable zone of its low-mass host star. K2-288Bb resides in a system with a unique architecture, as it orbits at >0.1 au from one component in a moderate separation binary (a proj ~ 55 au), and further follow-up may provide insight into its formation and evolution. Additionally, its estimated size straddles the observed gap in the planet radius distribution. Planets of this size occur less frequently and may be in a transient phase of radius evolution. K2-288 is the third transiting planet system identified by the Exoplanet Explorers program and its discovery exemplifies the value of citizen science in the era of Kepler, K2, and the Transiting Exoplanet Survey Satellite

    Meta-analysis of gene expression microarrays with missing replicates

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    <p>Abstract</p> <p>Background</p> <p>Many different microarray experiments are publicly available today. It is natural to ask whether different experiments for the same phenotypic conditions can be combined using meta-analysis, in order to increase the overall sample size. However, some genes are not measured in all experiments, hence they cannot be included or their statistical significance cannot be appropriately estimated in traditional meta-analysis. Nonetheless, these genes, which we refer to as <it>incomplete genes</it>, may also be informative and useful.</p> <p>Results</p> <p>We propose a meta-analysis framework, called "Incomplete Gene Meta-analysis", which can include incomplete genes by imputing the significance of missing replicates, and computing a meta-score for every gene across all datasets. We demonstrate that the incomplete genes are worthy of being included and our method is able to appropriately estimate their significance in two groups of experiments. We first apply the <it>Incomplete Gene Meta-analysis </it>and several comparable methods to five breast cancer datasets with an identical set of probes. We simulate incomplete genes by randomly removing a subset of probes from each dataset and demonstrate that our method consistently outperforms two other methods in terms of their false discovery rate. We also apply the methods to three gastric cancer datasets for the purpose of discriminating diffuse and intestinal subtypes.</p> <p>Conclusions</p> <p>Meta-analysis is an effective approach that identifies more robust sets of differentially expressed genes from multiple studies. The incomplete genes that mainly arise from the use of different platforms may also have statistical and biological importance but are ignored or are not appropriately involved by previous studies. Our Incomplete Gene Meta-analysis is able to incorporate the incomplete genes by estimating their significance. The results on both breast and gastric cancer datasets suggest that the highly ranked genes and associated GO terms produced by our method are more significant and biologically meaningful according to the previous literature.</p

    K2-136: A Binary System in the Hyades Cluster Hosting a Neptune-sized Planet

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    We report the discovery of a Neptune-size planet (R_p = 3.0 R⊕) in the Hyades Cluster. The host star is in a binary system, comprising a K5V star and M7/8V star with a projected separation of 40 au. The planet orbits the primary star with an orbital period of 17.3 days and a transit duration of 3 hrs. The host star is bright (V = 11.2, J = 9.1) and so may be a good target for precise radial velocity measurements. K2-136A c is the first Neptune-sized planet to be found orbiting in a binary system within an open cluster. The Hyades is the nearest star cluster to the Sun, has an age of 625–750 Myr, and forms one of the fundamental rungs in the distance ladder; understanding the planet population in such a well-studied cluster can help us understand and set constraints on the formation and evolution of planetary systems
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