53 research outputs found

    Quantification in cardiac MRI: advances in image acquisition and processing

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    Cardiac magnetic resonance (CMR) imaging enables accurate and reproducible quantification of measurements of global and regional ventricular function, blood flow, perfusion at rest and stress as well as myocardial injury. Recent advances in MR hardware and software have resulted in significant improvements in image quality and a reduction in imaging time. Methods for automated and robust assessment of the parameters of cardiac function, blood flow and morphology are being developed. This article reviews the recent advances in image acquisition and quantitative image analysis in CMR

    Characterization of the association between 8q24 and colon cancer: gene-environment exploration and meta-analysis

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    <p>Abstract</p> <p>Background</p> <p>Genome-wide association studies and subsequent replication studies have shown that single nucleotide polymorphisms (SNPs) in the chromosomal region 8q24 are associated with colorectal cancer susceptibility.</p> <p>Methods</p> <p>We examined 11 SNP markers in the 8q24 region between 128.47 and 128.54 Mb, using a total of 1,987 colon cases and 2,339 controls who self-reported as white from two independent, well-characterized study populations. Analysis was performed separately within each study, and combined using random effects meta-analysis. Logistic regression was used to estimate odds ratios (ORs) and 95% confidence intervals (95% CIs) and to test for effect modification by known colon cancer risk factors. We also performed a meta-analysis combining our results with previous studies.</p> <p>Results</p> <p>We observed evidence of association for four SNPs in low to high linkage disequilibrium (r<sup>2 </sup>ranging from 0.18 to 0.93) localized in a 16.2 kb region defined by rs10505477 and rs1056368. The combined results for our two studies of colon cancer showed an OR of 1.10 (95% CI: 1.01-1.20, P<sub>trend </sub>= 0.023), and a meta-analysis of our results with previously reported studies of colon and colorectal cancer strongly support the association for this SNP (combined OR for rs6983267 = 1.21, 95% CI: 1.18-1.24, p = 5.5 × 10<sup>-44</sup>). We did not observe any notable evidence of effect modification by known colon cancer risk factors, and risk did not differ significantly by tumor site or stage.</p> <p>Conclusions</p> <p>Our study confirms the association between polymorphisms on chromosome 8q24 and colon cancer risk and suggests that the susceptibility locus in region 8q24 is not strongly modified by various lifestyle, environmental, and demographic risk factors for colon cancer.</p

    Improved reference genome of Aedes aegypti informs arbovirus vector control

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    Female Aedes aegypti mosquitoes infect more than 400 million people each year with dangerous viral pathogens including dengue, yellow fever, Zika and chikungunya. Progress in understanding the biology of mosquitoes and developing the tools to fight them has been slowed by the lack of a high-quality genome assembly. Here we combine diverse technologies to produce the markedly improved, fully re-annotated AaegL5 genome assembly, and demonstrate how it accelerates mosquito science. We anchored physical and cytogenetic maps, doubled the number of known chemosensory ionotropic receptors that guide mosquitoes to human hosts and egg-laying sites, provided further insight into the size and composition of the sex-determining M locus, and revealed copy-number variation among glutathione S-transferase genes that are important for insecticide resistance. Using high-resolution quantitative trait locus and population genomic analyses, we mapped new candidates for dengue vector competence and insecticide resistance. AaegL5 will catalyse new biological insights and intervention strategies to fight this deadly disease vector

    Improved reference genome of Aedes aegypti informs arbovirus vector control

    Get PDF
    Female Aedes aegypti mosquitoes infect more than 400 million people each year with dangerous viral pathogens including dengue, yellow fever, Zika and chikungunya. Progress in understanding the biology of mosquitoes and developing the tools to fight them has been slowed by the lack of a high-quality genome assembly. Here we combine diverse technologies to produce the markedly improved, fully re-annotated AaegL5 genome assembly, and demonstrate how it accelerates mosquito science. We anchored physical and cytogenetic maps, doubled the number of known chemosensory ionotropic receptors that guide mosquitoes to human hosts and egg-laying sites, provided further insight into the size and composition of the sex-determining M locus, and revealed copy-number variation among glutathione S-transferase genes that are important for insecticide resistance. Using high-resolution quantitative trait locus and population genomic analyses, we mapped new candidates for dengue vector competence and insecticide resistance. AaegL5 will catalyse new biological insights and intervention strategies to fight this deadly disease vector

    Stereoselective synthesis of cyclopropanes based on a 1,2-chirality transfer

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    A stereoselective route to enantiomerically enriched bicyclic cyclopropane derivatives 13 is described which is based on a conceptually novel 1,2-chirality transfer approach. The hyperconjugative interaction of an electronically excited carbonyl group with the * orbital of an adjacent C-X bond in the transition state of a hydrogen abstraction causes the preference of a certain conformation and consequently the differentiation between two diastereotopic methylene groups. The 1,2-chirality transfer is completed by a subsequent HX elimination which destroys the only stereogenic center in the reactants 12. Furthermore, it was found that contrary enthalpic and entropic influences result in the existence of an inversion temperature T0. Upon crossing T0 the stereoselectivity is reversed. Considering this temperature dependency, chirality transfer efficiencies of up to 83% could be achieved. The absolute configuration of most products could be unambiguously determined by VCD sp ectroscopy combined with DFT calculations

    New class of oxygen carriers improves islet isolation from long-term stored rat pancreata.

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    OBJECTIVE: Pancreas shipment is frequently associated with prolonged ischemia deteriorating islet graft function. The strategy to prevent ischemic damage utilizing perfluorodecalin (PFD) for human pancreas oxygenation does not seem to improve isolation outcome. The present study investigated the efficiency of perfluorohexyloctane (F6H8), a hyperoxygen carrier characterized by low specific density (1.33 g/cm3) and lipophilic qualities, to facilitate islet isolation from long-term stored rat pancreata. MATERIALS AND METHODS: Prior to islet isolation, pancreata were intraductally flushed in situ with Kyoto solution (KS) and stored for 24 hours in KS, oxygenated PFD, or F6H8. RESULTS: Islet isolation performed after 24-hour storage in KS failed completely. The intrapancreatic pO2 in PFD- and F6H8-incubated pancreata was almost the same. In correspondence, the ATP content and viability of isolated islets were similar as well. In contrast, islet yield and in vitro function were significantly reduced after storage in PFD compared with F6H8. CONCLUSION: This study suggested that islet isolation performed after long-term pancreas preservation can be significantly improved utilizing semifluorinated alkanes as oxygen carriers
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