454 research outputs found

    Follicular regulatory T cells control humoral autoimmunity via NFAT2-regulated CXCR5 expression

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    Maturation of high-affinity B lymphocytes is precisely controlled during the germinal center reaction. This is dependent on CD4(+)CXCR5(+) follicular helper T cells (TFH) and inhibited by CD4(+)CXCR5(+)Foxp3(+) follicular regulatory T cells (TFR). Because NFAT2 was found to be highly expressed and activated in follicular T cells, we addressed its function herein. Unexpectedly, ablation of NFAT2 in T cells caused an augmented GC reaction upon immunization. Consistently, however, TFR cells were clearly reduced in the follicular T cell population due to impaired homing to B cell follicles. This was TFR-intrinsic because only in these cells NFAT2 was essential to up-regulate CXCR5. The physiological relevance for humoral (auto-)immunity was corroborated by exacerbated lupuslike disease in the presence of NFAT2-deficient TFR cells

    Overlapping of Ranges of Eastern and Western Hognose Snakes in Southeastern Iowa

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    Overlapping of ranges of the eastern hognose snake (Heterodon platyrhinos Latreille) and the western hognose snake (Heterodon nasicus nasicus Baird and Girrard) is reported from a sand prairie in Muscatine County, Iowa

    Improved Implementation of Point Location in General Two-Dimensional Subdivisions

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    We present a major revamp of the point-location data structure for general two-dimensional subdivisions via randomized incremental construction, implemented in CGAL, the Computational Geometry Algorithms Library. We can now guarantee that the constructed directed acyclic graph G is of linear size and provides logarithmic query time. Via the construction of the Voronoi diagram for a given point set S of size n, this also enables nearest-neighbor queries in guaranteed O(log n) time. Another major innovation is the support of general unbounded subdivisions as well as subdivisions of two-dimensional parametric surfaces such as spheres, tori, cylinders. The implementation is exact, complete, and general, i.e., it can also handle non-linear subdivisions. Like the previous version, the data structure supports modifications of the subdivision, such as insertions and deletions of edges, after the initial preprocessing. A major challenge is to retain the expected O(n log n) preprocessing time while providing the above (deterministic) space and query-time guarantees. We describe an efficient preprocessing algorithm, which explicitly verifies the length L of the longest query path in O(n log n) time. However, instead of using L, our implementation is based on the depth D of G. Although we prove that the worst case ratio of D and L is Theta(n/log n), we conjecture, based on our experimental results, that this solution achieves expected O(n log n) preprocessing time.Comment: 21 page

    Gene Expression Profiles from Needle Biopsies Provide Useful Signatures of Non-Small Cell Lung Carcinomas

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    Gene expression profiles from DNA microarrays can provide molecular signatures that improve tumor classification, prognosis, and treatment options. While much of this work has focused on isolation of RNA from the resected tumor, fewer studies have utilized RNA from fine needle aspirates (FNA). In this pilot study we examined whether the gene signatures obtained from FNA samples would correlate with signatures taken from the resected tumor. Based on NSCLC gene expression profiles obtained from eleven sets of FNA and tumor samples we obtained a high concordance of FNA profiles matching their matched tumor sample. These results suggest that FNA samples may provide informative gene expression signatures regarding the potential aggressiveness of non-small-cell lung carcinomas

    Motilitätsstörungen des Ösophagus

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    Zusammenfassung: Motilitätsstörungen des Ösophagus umfassen ein heterogenes Spektrum von Erkrankungen. Primäre Fehlbildungen des Ösophagus sind heute zwar einer verbesserten chirurgischen und gastroenterologischen Therapie zugänglich, führen jedoch zu langfristig persistierender ösophagealer Dysmotilität. Die Achalasie resultiert aus einer gestörten Relaxation des gastroösophagealen Sphinkters. Systemische Erkrankungen können mit einer sekundären ösophagealen Motilitätsstörung einhergehen. Zahlreiche neuromuskuläre Erkrankungen mit viszeraler Manifestation zeigen eine ösophageale Beteiligung. Selten kann eine Aganglionose bis in den Ösophagus reichen. Die wachsende Gruppe der Myopathien schließt metabolische und mitochondriale Störungen ein, deren zunehmende Charakterisierung genetischer Defekte vereinzelt bereits therapeutische Ansätze eröffnet. Infektbedingte Ösophagitiden zeigen besonders bei immunkompromittierten Patienten eine schwere Störung der Motilität. Immunologisch vermittelte Entzündungsprozesse im und um den Ösophagus werden allmählich besser verstanden. Schließlich können seltene Tumoren und tumorartige Läsionen eine Dysmotilität des Ösophagus verursache

    Motion Planning via Manifold Samples

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    We present a general and modular algorithmic framework for path planning of robots. Our framework combines geometric methods for exact and complete analysis of low-dimensional configuration spaces, together with practical, considerably simpler sampling-based approaches that are appropriate for higher dimensions. In order to facilitate the transfer of advanced geometric algorithms into practical use, we suggest taking samples that are entire low-dimensional manifolds of the configuration space that capture the connectivity of the configuration space much better than isolated point samples. Geometric algorithms for analysis of low-dimensional manifolds then provide powerful primitive operations. The modular design of the framework enables independent optimization of each modular component. Indeed, we have developed, implemented and optimized a primitive operation for complete and exact combinatorial analysis of a certain set of manifolds, using arrangements of curves of rational functions and concepts of generic programming. This in turn enabled us to implement our framework for the concrete case of a polygonal robot translating and rotating amidst polygonal obstacles. We demonstrate that the integration of several carefully engineered components leads to significant speedup over the popular PRM sampling-based algorithm, which represents the more simplistic approach that is prevalent in practice. We foresee possible extensions of our framework to solving high-dimensional problems beyond motion planning.Comment: 18 page

    Multiple roles of GluN2B-containing NMDA receptors in synaptic plasticity in juvenile hippocampus

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    AbstractIn the CA1 area of the hippocampus N-methyl-d-aspartate receptors (NMDARs) mediate the induction of long-term depression (LTD), short-term potentiation (STP) and long-term potentiation (LTP). All of these forms of synaptic plasticity can be readily studied in juvenile hippocampal slices but the involvement of particular NMDAR subunits in the induction of these different forms of synaptic plasticity is currently unclear. Here, using NVP-AAM077, Ro 25-6981 and UBP145 to target GluN2A-, 2B- and 2D-containing NMDARs respectively, we show that GluN2B-containing NMDARs (GluN2B) are involved in the induction of LTD, STP and LTP in slices prepared from P14 rat hippocampus. A concentration of Ro (1 μM) that selectively blocks GluN2B-containing diheteromers is able to block LTD. It also inhibits a component of STP without affecting LTP. A higher concentration of Ro (10 μM), that also inhibits GluN2A/B triheteromers, blocks LTP. UBP145 selectively inhibits the Ro-sensitive component of STP whereas NVP inhibits LTP. These data are consistent with a role of GluN2B diheretomers in LTD, a role of both GluN2B- and GluN2D- containing NMDARs in STP and a role of GluN2A/B triheteromers in LTP.This article is part of the Special Issue entitled ‘Ionotropic glutamate receptors’

    What’s in a Name? Use of Brand versus Generic Drug Names in United States Outpatient Practice

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    BACKGROUND: The use of brand rather than generic names for medications can increase health care costs. However, little is known at a national level about how often physicians refer to drugs using their brand or generic names. OBJECTIVE: To evaluate how often physicians refer to drugs using brand or generic terminology. DESIGN AND PARTICIPANTS: We used data from the 2003 National Ambulatory Medical Care Survey (NAMCS), a nationally representative survey of 25,288 community-based outpatient visits in the United States. After each visit, patient medications were recorded on a survey encounter form by the treating physician or transcribed from office notes. MEASUREMENTS: Our main outcome measure was the frequency with which medications were recorded on the encounter form using their brand or generic names. RESULTS: For 20 commonly used drugs, the median frequency of brand name use was 98% (interquartile range, 81–100%). Among 12 medications with no generic competition at the time of the survey, the median frequency of brand name use was 100% (range 92–100%). Among 8 medications with generic competition at the time of the survey (“multisource” drugs), the median frequency of brand name use was 79% (range 0–98%; P < .001 for difference between drugs with and without generic competition). CONCLUSIONS: Physicians refer to most medications by their brand names, including drugs with generic formulations. This may lead to higher health care costs by promoting the use of brand-name products when generic alternatives are available

    Surface modification of Ti-4Al-2V alloy by nitrogen implantation

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    Ti-4Al-2V is a new type of alpha titanium alloy that suitable for the application in high-temperature and high-pressure water/steam environment. Ti-4Al-2V can be used in marine engineering, nuclear power industry. In this paper the surface characterization of the Ti-4Al-2V implanted with 75 keV nitrogen with fluences of 3 × 10 17 and 8 × 10 17  N + /cm 2 is investigated by glancing-incidence XRD, XPS and microhardness. The results show that new phase TiN are formed after N implantation in the surface region. The nitrogen implantation increases the surface hardness up to 340 and 260% for fluence of 8 × 10 17 and 3 × 10 17  N + /cm 2 , respectively. The enhancement of hardness is related to the formation of TiN and irradiation induced hardness.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/43177/1/10853_2005_Article_5365.pd
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