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251.
252.
Jody A. O’Connor Frank J. Sulloway Jeremy Robertson Sonia Kleindorfer 《Biodiversity and Conservation》2010,19(3):853-866
Darwin’s medium tree finch (Camarhynchus pauper) meets the 2009 International Union for Conservation of Nature Red List criteria for a critically endangered species because it has “a very small range on a single island” and is “declining rapidly owing to the effects of the parasite Philornis downsi”, habitat degradation, and introduced predators. The medium tree finch is only found in patches of remnant highland forest on Floreana Island, where it co-exists with breeding populations of small and large tree finches (C. parvulus and C. psittacula). Here, we examine the intensity of P. downsi in nests of small, medium, and large tree finches on Floreana. We expected that parasite intensity would increase with finch body size, and with greater rainfall, and would also correlate with increased nestling mortality. We found a trend in the expected direction for parasite intensity and rainfall. Combined meta-analytically with data from a previous study, the overall trend for the two studies was significant. We also found a significant linear trend in parasite intensity with finch body size. In addition, the medium tree finch exhibited a somewhat higher parasite intensity than would be expected based on body mass alone. Of 63 active medium tree finch nests, 17 nests had nestlings: all of which were infested with P. downsi. Only 25% of medium tree finch nestlings fledged, 28% were depredated, 41% died due to P. downsi parasitism, and 6% died for other reasons. 相似文献
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254.
Talbi C Lemey P Suchard MA Abdelatif E Elharrak M Nourlil J Jalal N Faouzi A Echevarría JE Vazquez Morón S Rambaut A Campiz N Tatem AJ Holmes EC Bourhy H 《PLoS pathogens》2010,6(10):e1001166
Understanding the role of humans in the dispersal of predominantly animal pathogens is essential for their control. We used newly developed Bayesian phylogeographic methods to unravel the dynamics and determinants of the spread of dog rabies virus (RABV) in North Africa. Each of the countries studied exhibited largely disconnected spatial dynamics with major geopolitical boundaries acting as barriers to gene flow. Road distances proved to be better predictors of the movement of dog RABV than accessibility or raw geographical distance, with occasional long distance and rapid spread within each of these countries. Using simulations that bridge phylodynamics and spatial epidemiology, we demonstrate that the contemporary viral distribution extends beyond that expected for RABV transmission in African dog populations. These results are strongly supportive of human-mediated dispersal, and demonstrate how an integrated phylogeographic approach will turn viral genetic data into a powerful asset for characterizing, predicting, and potentially controlling the spatial spread of pathogens. 相似文献
255.
Sara Da Pieve Sonia Calligaris Edmund Co Maria C. Nicoli Alejandro G. Marangoni 《Food biophysics》2010,5(3):211-217
The aim of the present research was to study the effect of shear on the crystallization behavior of monoglyceride organogels.
To this end, organogels were prepared by mixing cod liver oil and saturated monoglycerides at 80°C and then crystallizing
them at 20°C under shear rates ranging from 0 to 2,000 s−1. The organogels were characterized using polarized light microscopy, Cryo-SEM, and X-ray diffraction. The rheological properties
and the oil binding capacity of the different systems were also evaluated. Results obtained in this study showed that the
introduction of shear during organogel formation greatly affects structure at the nano, micro, and macro levels. Solidification
of the organogel under static conditions led to the formation of a strong gel network, with a high oil binding capacity. On
the contrary, shear processing during crystallization led to the formation of a weak gel network with a low oil binding capacity. 相似文献
256.
El-Armouche A Wahab A Wittköpper K Schulze T Böttcher F Pohlmann L King SB DuMond JF Gerloff C Böger RH Eschenhagen T Carrier L Donzelli S 《Biochemical and biophysical research communications》2010,397(2):340-344
Haplotype, which is the sequence of SNPs in a specific chromosome, plays an important role in disease association studies. However, current sequencing techniques can detect the presence of SNP sites, but they cannot tell which copy of a pair of chromosomes the alleles belong to. Moreover, sequencing errors that occurred in sequencing SNP fragments make it difficult to determine a pair of haplotypes from SNP fragments. To help overcome this difficulty, the haplotype assembly problem is defined from the viewpoint of computation, and several models are suggested to tackle this problem. However, there are no freely available web-based tools to overcome this problem as far as we are aware. In this paper, we present a web-based application based on the genetic algorithm, named HapAssembler, for assembling a pair of haplotypes from SNP fragments. Numerical results on real biological data show that the correct rate of the proposed application in this paper is greater than 95% in most cases. HapAssembler is freely available at http://alex.chonnam.ac.kr/~drminor/hapHome.htm. Users can choose any model among four models for their purpose and determine haplotypes from their input data. 相似文献
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Cristina Oliveras-Ferraros Alejandro Vazquez-Martin Begoña Martin-Castillo Silvia Cufí Sonia Del Barco Eugeni Lopez-Bonet Javier A. Menendez 《Biochemical and biophysical research communications》2010,397(1):27-1021
Evidence is mounting that the occurrence of the CD44pos/CD24neg/low cell population, which contains potential breast cancer (BC) stem cells, could explain BC clinical resistance to HER2-targeted therapies. We investigated whether de novo refractoriness to the anti-HER2 monoclonal antibody trastuzumab (Tzb; Herceptin) may relate to the dynamic regulation of the mesenchymal CD44pos/CD24neg/low phenotype in HER2-positive BC. We observed that the subpopulation of Tzb-refractory JIMT-1 BC cells exhibiting CD44pos/CD24neg/low-surface markers switched with time. Low-passage JIMT-1 cell cultures were found to spontaneously contain ∼10% of cells bearing the CD44pos/CD24neg/low immunophenotype. Late-passage (>60) JIMT-1 cultures accumulated ∼80% of CD44pos/CD24neg/low cells and closely resembled the CD44pos/CD24neg/low-enriched (∼85%) cell population constitutively occurring in HER2-negative MDA-MB-231 mesenchymal BC cells. Dynamic expression of mesenchymal markers was not limited to CD44/CD24 because high-passages of JIMT-1 cells exhibited also reduced expression of the HER2 protein and over-secretion of pro-invasive/metastatic chemokines and metalloproteases. Accordingly, late-passage JIMT-1 cells displayed an exacerbated migratogenic phenotype in plastic, collagen, and fibronectin substrates. Intrinsic genetic plasticity to efficiently drive the emergence of the CD44pos/CD24neg/low mesenchymal phenotype may account for de novo resistance to HER2 targeting therapies in basal-like BC carrying HER2 gene amplification. 相似文献
259.
Sonia Lewycka Charles Mwansambo Peter Kazembe Tambosi Phiri Andrew Mganga Mikey Rosato Hilda Chapota Florida Malamba Stefania Vergnano Marie-Louise Newell David Osrin Anthony Costello 《Trials》2010,11(1):1-15
Background
Paclitaxel-eluting stents decrease angiographic and clinical restenosis following percutaneous coronary intervention compared to bare metal stents. TAXUS Element is a third-generation paclitaxel-eluting stent which incorporates a novel, thinner-strut, platinum-enriched metal alloy platform. The stent is intended to have enhanced radiopacity and improved deliverability compared to other paclitaxel-eluting stents. The safety and efficacy of the TAXUS Element stent are being evaluated in the pivotal PERSEUS clinical trials.Methods/Design
The PERSEUS trials include two parallel studies of the TAXUS Element stent in single, de novo coronary atherosclerotic lesions. The PERSEUS Workhorse study is a prospective, randomized (3:1), single-blind, non-inferiority trial in subjects with lesion length ≤28 mm and vessel diameter ≥2.75 mm to ≤4.0 mm which compares TAXUS Element to the TAXUS Express2 paclitaxel-eluting stent system. The Workhorse study employs a novel Bayesian statistical approach that uses prior information to limit the number of study subjects exposed to the investigational device and thus provide a safer and more efficient analysis of the TAXUS Element stent. PERSEUS Small Vessel is a prospective, single-arm, superiority trial in subjects with lesion length ≤20 mm and vessel diameter ≥2.25 mm to <2.75 mm that compares TAXUS Element with a matched historical bare metal Express stent control.Discussion
The TAXUS PERSEUS clinical trial program uses a novel statistical approach to evaluate whether design and metal alloy iterations in the TAXUS Element stent platform provide comparable safety and improved procedural performance compared to the previous generation Express stent. PERSEUS trial enrollment is complete and primary endpoint data are expected in 2010. PERSEUS Workhorse and Small Vessel are registered at http://www.clinicaltrials.gov, identification numbers NCT00484315 and NCT00489541. 相似文献260.
Francisco Martínez Sandra Monfort Mónica Roselló Silvestre Oltra David Blesa Ramiro Quiroga Sonia Mayo Carmen Orellana 《BMC medical genomics》2010,3(1):1-6