985 resultados para THIRD GENERATION
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Transcription Activator-Like Effector Nucleases (TALEN) are potential tools for precise genome engineering of laboratory animals. We report the first targeted genomic integration in the rat using TALENs (Transcription Activator-Like Effector Nucleases) by homology-derived recombination (HDR). We assembled TALENs and designed a linear donor insert targeting a pA476T mutation in the rat Glucocorticoid Receptor (Nr3c1) namely GR(dim), that prevents receptor homodimerization in the mouse. TALEN mRNA and linear double-stranded donor were microinjected into rat one-cell embryos. Overall, we observed targeted genomic modifications in 17% of the offspring, indicating high TALEN cutting efficiency in rat zygotes.
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Abstract: Blocking tumor growth by targeting the tumor vasculature is a promising approach in cancer therapy. Both, disrupting tumor vessels as well as normalization of tumor vessel abnormalities have shown anti-cancer efficacy. A plethora of agents that act on the tumor vasculature have been developed; however, so far few have shown clinical benefits. Among the successful agents, inhibitors of the mammalian target of rapamycin (mTOR) are able to reduce tumor growth by targeting tumor vessels. mTOR inhibition exerts at least three different effects on the tumor vasculature. First, it reduces tumor angiogenesis. Second it normalizes the tumor vasculature and third, it promotes the formation of thrombosis in tumor vessels. The characterization of the molecular functions regulated by mTOR and of relevance to the tumor vasculature is therefore important in order to further identify biological mechanisms involved in the tumor vascular network as well as to improve the efficacy of these inhibitors. Here, we will first enumerate the evidences for the anti-angiogenic activities of mTOR inhibitors and describe the molecular mechanisms involved. We will further analyze the effects of mTOR inhibition on vascular normalization and also describe how mTOR inhibition promotes thrombosis formation specifically in tumor vessels. Finally, we will describe a new generation of mTOR inhibitors and examine their effects on the tumor vasculature
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Résumé La voie de signalisation de Wnt est extrêmement conservée au cours de l'évolution. Les protéines Wnt sont des molécules sécrétées qui se lient à la famille de récepteurs Frizzled. Cette interaction mène à la stabilisation de la protéine β-caténine, qui va s'accumuler dans le cytoplasme puis migrer dans le noyau où elle peut s'hétérodimériser avec les facteurs de transcription de la famille TCF/LEF. Il a été démontré que cette voie de signalisation joue un rôle important durant la lymphopoïèse et de récents résultats suggèrent un rôle clé de cette voie dans le renouvellement des Cellules Souches Hématopoïétique (CSH). Des études se basant sur un système de surexpression de protéines montrent clairement que la voie Wnt peut influencer l'hématopoïèse. Cependant, le rôle de la protéine β-caténine dans le système hématopoïétique n'a jamais été testé directement. Ce projet de thèse se propose d'étudier la fonction de la protéine β-caténine par sa délétion inductible via le système Cre-loxP. De façon surprenante, nous avons pu démontrer que les progéniteurs de la moelle osseuse, déficients en β-caténine, ne montrent aucune altération dans leur capacité à s'auto-renouveler et/ou à reconstituer toutes les lignées hématopoïétiques (myéloïde, érythroïde et lymphoïde) dans les souris-chimères. De plus, le développement, la survie des thymocytes ainsi que la prolifération des cellules T périphériques induite par un antigène, sont indépendants de β-caténine. Ces résultats suggèrent soit que la protéine β-caténine ne joue pas un rôle primordial dans le système hématopoiétique, soit que son absence pourrait être compensée par une autre protéine. Un candidat privilégié susceptible de se substituer à β-caténine, serait plakoglobine, aussi connu sous le nom de γ-caténine. En effet, ces deux protéines partagent de multiples caractéristiques structurelles. Afin de démontrer que la protéine γ-caténine peut compenser l'absence de β-caténine, nous avons généré des souris dans lesquelles, le système hématopoïétique est déficient pour ces deux protéines. Cette déficience combinée de β- caténine et γ-caténine ne perturbe pas la capacité des Cellules Souche Hématopoïétique-Long Terme (CSH-LT) de se renouveler, par contre elle agit sur un progéniteur précoce déjà différencié de la moelle osseuse. Ces résultats mettent en évidence que la protéine γ-caténine est capable de compenser l'absence de protéine β-caténine dans le système hématopoïétique. Par conséquent, ce travail contribue à une meilleure connaissance de la cascade Wnt dans l'hématopoïèse. Summary The canonical Wnt signal transduction pathway is a developmentally highly conserved. Wnts are secreted molecules which bind to the family of Frizzled receptors in a complex with the low density lipoprotein receptor related protein (LRP-5/6). This initial activation step leads to the stabilization and accumulation of β-catenin, first in the cytoplasm and subsequently in the nucleus where it forms heterodimers with TCF/LEF transcription factor family members. Wnt signalling has been shown to be important during early lymphopoiesis and has more recently, been suggested to be a key player in self-renewal of haematopoietic stem cells (HSCs). Although mostly gain of function studies indicate that components of the Wnt signalling pathway can influence the haematopoietic system, the role of β-catenin has never been directly investigated. The aim of this thesis project is to investigate the putatively critical role of β-catenin in vivo using the Cre-loxP mediated conditional loss of function approach. Surprisingly, β-catenin deficient bone marrow (BM) progenitors arc not impaired in their ability to self-renew and/or to reconstitute all haematopoietic lineages (myeloid, erythroid and lymphoid) in both mixed and straight bone marrow chimeras. In addition, both thymocyte development and survival, and antigen-induced proliferation of peripheral T cells are β- catenin independent. Our results do not necessarily exclude the possibility of an important function for β-catenin mediated Wnt signalling in the haematopoietic system, it rather raises the question that β-catenin is compensated for by another protein. A prime candidate that may take over the function of β-catenin in its absence, is the close relative plakoglobin, also know as γ-catenin. This protein shares multiple structural features with β-catenin. In order to investigate whether γ-catenin can compensate for the loss of β-catenin we have generated mice in which the haematopoietic compartment is deficient for both proteins. Combined deficiency of β-catenin and γ-catenin does not perturb Long Term-Haematopoietic Stem Cells (LT-HSC) self renewal, but affects an already lineage committed progenitor population within the BM. Our results demonstrate that y-catenin can indeed compensate for the loss of β-catenin within the haematopoietie system.
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A precise and simple computational model to generate well-behaved two-dimensional turbulent flows is presented. The whole approach rests on the use of stochastic differential equations and is general enough to reproduce a variety of energy spectra and spatiotemporal correlation functions. Analytical expressions for both the continuous and the discrete versions, together with simulation algorithms, are derived. Results for two relevant spectra, covering distinct ranges of wave numbers, are given.
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We present a nonequlibrium approach for the study of a flexible bilayer whose two components induce distinct curvatures. In turn, the two components are interconverted by an externally promoted reaction. Phase separation of the two species in the surface results in the growth of domains characterized by different local composition and curvature modulations. This domain growth is limited by the effective mixing due to the interconversion reaction, leading to a finite characteristic domain size. In addition to these effects, first introduced in our earlier work [ Phys. Rev. E 71 051906 (2005)], the important new feature is the assumption that the reactive process actively affects the local curvature of the bilayer. Specifically, we suggest that a force energetically activated by external sources causes a modification of the shape of the membrane at the reaction site. Our results show the appearance of a rich and robust dynamical phenomenology that includes the generation of traveling and/or oscillatory patterns. Linear stability analysis, amplitude equations, and numerical simulations of the model kinetic equations confirm the occurrence of these spatiotemporal behaviors in nonequilibrium reactive bilayers.
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High-fidelity 'proofreading' polymerases are often used in library construction for next-generation sequencing projects, in an effort to minimize errors in the resulting sequence data. The increased template fidelity of these polymerases can come at the cost of reduced template specificity, and library preparation methods based on the AFLP technique may be particularly susceptible. Here, we compare AFLP profiles generated with standard Taq and two versions of a high-fidelity polymerase. We find that Taq produces fewer and brighter peaks than high-fidelity polymerase, suggesting that Taq performs better at selectively amplifying templates that exactly match the primer sequences. Because the higher accuracy of proofreading polymerases remains important for sequencing applications, we suggest that it may be more effective to use alternative library preparation methods.
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This report includes discussions of the general subject of water resources and flood control, including the presentation of facts and arguments which were considered in the drafting of this report. It also discusses various bills presented and a brief explanation of each bill.
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The process of comparing a fingermark recovered from a crime scene with the fingerprint taken from a known individual involves the characterization and comparison of different ridge details on both the mark and the print. Fingerprints examiners commonly classify these characteristics into three different groups, depending on their level of discriminating power. It is commonly considered that the general pattern of the ridge flow constitutes first-level detail, specific ridge flow and minutiaes (e.g. ending ridges, bifurcations) constitutes second-level detail, and fine ridge details (e. g. pore positions and shapes) are described as third-level details.In this study, the reproducibility of a selection of third-level characteristics is investigated. The reproducibility of these features is examined on serveral recordings of a same finger, first acquired using only optical visualization techniques and second on impressions developed using common firngermark development techniques. Prior to the evaluation of the reproducibility of the considered characteristics, digital images of the fingerprints were recorded at two different resolutions (1000 and 2000 ppi). This allowed the study to also examine the influence of higher resolution on the considered characteristics. It was observed that the increase in the resolution did not result in better feature detection or comparison between images.The examination of the reproducibility of a selection of third-level characteristics showed that the most reproducible features observed were minutiae shapes and pore positions along the ridges.
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BACKGROUND: Adalimumab (ADA) and certolizumab pegol (CZP) have demonstrated efficacy in Crohn's disease (CD) patients previously treated with infliximab (IFX). AIM: To assess the efficacy and tolerability of a third anti-TNF in CD after failure of and/or intolerance to two different anti-TNF antibodies. METHODS: Crohn's disease patients who received ADA or CZP after loss of response and/or intolerance to two anti-TNF agent were included in this retrospective study. Data were collected using a standardized questionnaire. Clinical response, duration, safety and reasons for discontinuation were assessed. RESULTS: Sixty-seven patients treated with CZP (n = 40) or ADA (n = 27) were included. A clinical response was observed in 41 (61%) at week 6 and 34 patients (51%) at week 20. The probability of remaining under treatment at 3 months, 6 months and 9 months was 68%, 60% and 45%, respectively. At the end of follow-up, the third anti-TNF had been stopped in 36 patients for intolerance (n = 13), or failure (n = 23). Two deaths were observed. CONCLUSIONS: The treatment with a third anti-TNF (CZP or ADA) agent of CD patients, who have experienced loss of response and/or intolerance to two anti-TNF antibodies, has favourable short-term and long-term efficacy. It is an option to be considered in patients with no other therapeutic options.
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Recent construction of new generation power plants burning western coal within Iowa has resulted in fly Ash production on the order of 760,000 tons annually. Although fly ash has long been accepted as a valuable replacement for portland cement in concrete, most experience has been with fly ash generated from eastern bituminous coals. A few years ago, fly ash in Iowa was not a significant factor because production was small and economics dictated disposal as the better alternative than construction use. Today, the economic climate, coupled with abundance of the material, makes constructive use in concrete feasible. The problem is, however, fly ash produced from new power plants is different than that for which information was available. It seems fly ash types have outgrown existing standards. The objective of this study was to develop fundamental information about fly ashes available to construction in Iowa such that its advantages and limitations as replacement to portland cement can be defined. Evaluative techniques used in this work involve sophisticated laboratory equipment, not readily available to potential fly ash users, so a second goal was preliminary development of rapid diagnostic tests founded on fundamental information. Lastly, Iowa Department of Transportation research indicated an interesting interdependency among coarse aggregate type, fly ash and concrete's resistance to freeze-thaw action. Thus a third charge of this research project was to verify and determine the cause for the phenomena. One objective of this project was to determine properties of Iowa fly ashes and evaluate their relevance to use of the material as an admixture of PCC. This phase of the research involved two approaches. The first involved the development of a rapid method for determining quantitative elemental composition while the second was aimed at both qualitative and quantitative determination of compounds. X-ray fluorescence techniques were adapted for rapid determination of elemental composition of fly ash. The analysis was performed using a Siemens SR-200 sequential x-ray spectrometer controlled by a PDP-11-03 microcomputer. The spectrometer was equipped with a ten sample specimen chamber and four interchangeable analyzing crystals. Unfiltered excitation radiation was generated using a chromium tube at 50 KV and 48 ma. Programs for the spectrometer were developed by the Siemens Corporation.
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OBJECTIVE: To explore the user-friendliness and ergonomics of seven new generation intensive care ventilators. DESIGN: Prospective task-performing study. SETTING: Intensive care research laboratory, university hospital. METHODS: Ten physicians experienced in mechanical ventilation, but without prior knowledge of the ventilators, were asked to perform eight specific tasks [turning the ventilator on; recognizing mode and parameters; recognizing and setting alarms; mode change; finding and activating the pre-oxygenation function; pressure support setting; stand-by; finding and activating non-invasive ventilation (NIV) mode]. The time needed for each task was compared to a reference time (by trained physiotherapist familiar with the devices). A time >180 s was considered a task failure. RESULTS: For each of the tests on the ventilators, all physicians' times were significantly higher than the reference time (P < 0.001). A mean of 13 +/- 8 task failures (16%) was observed by the ventilator. The most frequently failed tasks were mode and parameter recognition, starting pressure support and finding the NIV mode. Least often failed tasks were turning on the pre-oxygenation function and alarm recognition and management. Overall, there was substantial heterogeneity between machines, some exhibiting better user-friendliness than others for certain tasks, but no ventilator was clearly better that the others on all points tested. CONCLUSIONS: The present study adds to the available literature outlining the ergonomic shortcomings of mechanical ventilators. These results suggest that closer ties between end-users and manufacturers should be promoted, at an early development phase of these machines, based on the scientific evaluation of the cognitive processes involved by users in the clinical setting.
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Epistatic effects involving genic combinations of fixed and non fixed genes are shown to contribute to the genotypic mean of any population. These effects define specific additive x additive and additive x dominant epistatic components. As such components are not estimable, their relative importance cannot be assessed. These epistatic effects can cause bias in the estimates of the additive and dominance components to which they are confounded. The magnitude of the bias depends on the relative values of the epistatic effects, comparatively to deviations d and h, type of prevailing epistasis and direction of dominance.