296 research outputs found

    Direct demonstration of an HLA-DR allotypic determinant on the low molecular weight (beta) subunit using a mouse monoclonal antibody specific for DR3

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    A murine monoclonal antibody directed against a human B cell surface antigen with the characteristics of HLA-DR is described. The antigen detected is tightly linked to HLA and is correlated with the alloantigen HLA-Dw/DR3. Reactivity with a fraction of Dw/DRw6 cells is also observed. The determinant recognized by this antibody has been shown to be present on the smaller molecular weight β subunit of the HLA-DR antigen

    First direct detection of an exoplanet by optical interferometry; Astrometry and K-band spectroscopy of HR8799 e

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    To date, infrared interferometry at best achieved contrast ratios of a few times 10410^{-4} on bright targets. GRAVITY, with its dual-field mode, is now capable of high contrast observations, enabling the direct observation of exoplanets. We demonstrate the technique on HR8799, a young planetary system composed of four known giant exoplanets. We used the GRAVITY fringe tracker to lock the fringes on the central star, and integrated off-axis on the HR8799e planet situated at 390 mas from the star. Data reduction included post-processing to remove the flux leaking from the central star and to extract the coherent flux of the planet. The inferred K band spectrum of the planet has a spectral resolution of 500. We also derive the astrometric position of the planet relative to the star with a precision on the order of 100μ\,\muas. The GRAVITY astrometric measurement disfavors perfectly coplanar stable orbital solutions. A small adjustment of a few degrees to the orbital inclination of HR 8799 e can resolve the tension, implying that the orbits are close to, but not strictly coplanar. The spectrum, with a signal-to-noise ratio of 5\approx 5 per spectral channel, is compatible with a late-type L brown dwarf. Using Exo-REM synthetic spectra, we derive a temperature of 1150±501150\pm50\,K and a surface gravity of 104.3±0.310^{4.3\pm0.3}\,cm/s2^{2}. This corresponds to a radius of 1.170.11+0.13RJup1.17^{+0.13}_{-0.11}\,R_{\rm Jup} and a mass of 104+7MJup10^{+7}_{-4}\,M_{\rm Jup}, which is an independent confirmation of mass estimates from evolutionary models. Our results demonstrate the power of interferometry for the direct detection and spectroscopic study of exoplanets at close angular separations from their stars.Comment: published in A&

    Radiolabeled CCK/gastrin peptides for imaging and therapy of CCK2 receptor-expressing tumors

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    Cholecystokinin (CCK) receptors are overexpressed in numerous human cancers, like medullary thyroid carcinomas, small cell lung cancers and stromal ovarian cancers. The specific receptor-binding property of the endogenous ligands for these receptors can be exploited by labeling peptides with a radionuclide and using these as carriers to guide the radioactivity to the tissues that express the receptors. In this way, tumors can be visualized using positron emission tomography and single photon emission computed tomography imaging. A variety of radiolabeled CCK/gastrin-related peptides has been synthesized and characterized for imaging. All peptides have the C-terminal CCK receptor-binding tetrapeptide sequence Trp-Met-Asp-Phe-NH2 in common or derivatives thereof. This review focuses on the development and application of radiolabeled CCK/gastrin peptides for radionuclide imaging and radionuclide therapy of tumors expressing CCK receptors. We discuss both preclinical studies as well as clinical studies with CCK and gastrin peptides

    Localization of the murine cholecystokinin A and B receptor genes

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    We have determined the chromosomal locations of the two cholecystokinin (CCK) receptor genes in the mouse. Genetic localization utilized an interspecific backcross panel formed from the cross (C57BL/6J x Mus spretus ) F 1 x Mus spretus . Genomic DNAs from 94 individuals in the backcross were analyzed by Southern hybridization with rat CCK A and CCK B receptor cDNA probes. Unique map positions were determined by haplotype analysis with 650 previously mapped loci in the mouse backcross. The CCK A receptor gene ( Cckar ) mapped to mouse Chromosome (Chr) 5, in tight linkage with the DNA marker D5Bir8 . The CCK B receptor gene ( Cckbr ) mapped to mouse Chr 7, tightly linked to the β-hemoglobin locus ( Hbb ). This localization places Cckbr in the same region as the mouse obesity mutation tubby ( tub ), which also maps near Hbb (2.4±1.4 cM). Since CCK can function as a satiety factor when administered to rodents, localization of Cckbr near the tub mutation identifies this receptor as a possible candidate gene for this obesity mutation.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/47021/1/335_2004_Article_BF00352408.pd

    Interaction between polymorphisms of the Human Leukocyte Antigen and HPV-16 Variants on the risk of invasive cervical cancer

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    <p>Abstract</p> <p>Background</p> <p>Persistent infection with oncogenic types of human papillomavirus (HPV) is the major risk factor for invasive cervical cancer (ICC), and non-European variants of HPV-16 are associated with an increased risk of persistence and ICC. HLA class II polymorphisms are also associated with genetic susceptibility to ICC. Our aim is to verify if these associations are influenced by HPV-16 variability.</p> <p>Methods</p> <p>We characterized HPV-16 variants by PCR in 107 ICC cases, which were typed for <it>HLA-DQA1</it>, <it>DRB1 </it>and <it>DQB1 </it>genes and compared to 257 controls. We measured the magnitude of associations by logistic regression analysis.</p> <p>Results</p> <p>European (E), Asian-American (AA) and African (Af) variants were identified. Here we show that inverse association between <it>DQB1*05 </it>(adjusted odds ratio [OR] = 0.66; 95% confidence interval [CI]: 0.39–1.12]) and HPV-16 positive ICC in our previous report was mostly attributable to AA variant carriers (OR = 0.27; 95%CI: 0.10–0.75). We observed similar proportions of <it>HLA DRB1*1302 </it>carriers in E-P positive cases and controls, but interestingly, this allele was not found in AA cases (p = 0.03, Fisher exact test). A positive association with <it>DRB1*15 </it>was observed in both groups of women harboring either E (OR = 2.99; 95% CI: 1.13–7.86) or AA variants (OR = 2.34; 95% CI: 1.00–5.46). There was an inverse association between <it>DRB1*04 </it>and ICC among women with HPV-16 carrying the 350T [83L] single nucleotide polymorphism in the <it>E6 </it>gene (OR = 0.27; 95% CI: 0.08–0.96). An inverse association between <it>DQB1*05 </it>and cases carrying 350G (83V) variants was also found (OR = 0.37; 95% CI: 0.15–0.89).</p> <p>Conclusion</p> <p>Our results suggest that the association between HLA polymorphism and risk of ICC might be influenced by the distribution of HPV-16 variants.</p

    Effects of an attention demanding task on dynamic stability during treadmill walking

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    <p>Abstract</p> <p>Background</p> <p>People exhibit increased difficulty balancing when they perform secondary attention-distracting tasks while walking. However, a previous study by Grabiner and Troy (<it>J. Neuroengineering Rehabil</it>., 2005) found that young healthy subjects performing a concurrent Stroop task while walking on a motorized treadmill exhibited <it>decreased </it>step width variability. However, measures of variability do not directly quantify how a system responds to perturbations. This study re-analyzed data from Grabiner and Troy 2005 to determine if performing the concurrent Stroop task directly affected the dynamic stability of walking in these same subjects.</p> <p>Methods</p> <p>Thirteen healthy volunteers walked on a motorized treadmill at their self-selected constant speed for 10 minutes both while performing the Stroop test and during undisturbed walking. This Stroop test consisted of projecting images of the name of one color, printed in text of a different color, onto a wall and asking subjects to verbally identify the color of the text. Three-dimensional motions of a marker attached to the base of the neck (C5/T1) were recorded. Marker velocities were calculated over 3 equal intervals of 200 sec each in each direction. Mean variability was calculated for each time series as the average standard deviation across all strides. Both "local" and "orbital" dynamic stability were quantified for each time series using previously established methods. These measures directly quantify how quickly small perturbations grow or decay, either continuously in real time (local) or discretely from one cycle to the next (orbital). Differences between Stroop and Control trials were evaluated using a 2-factor repeated measures ANOVA.</p> <p>Results</p> <p>Mean variability of trunk movements was significantly reduced during the Stroop tests compared to normal walking. Conversely, local and orbital stability results were mixed: some measures showed slight increases, while others showed slight decreases. In many cases, different subjects responded differently to the Stroop test. While some of our comparisons reached statistical significance, many did not. In general, measures of variability and dynamic stability reflected different properties of walking dynamics, consistent with previous findings.</p> <p>Conclusion</p> <p>These findings demonstrate that the decreased movement variability associated with the Stroop task did <it>not </it>translate to greater dynamic stability.</p

    Co-optation & Clientelism: Nested Distributive Politics in China’s Single-Party Dictatorship

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    What explains the persistent growth of public employment in reform-era China despite repeated and forceful downsizing campaigns? Why do some provinces retain more public employees and experience higher rates of bureaucratic expansion than others? Among electoral regimes, the creation and distribution of public jobs is typically attributed to the politics of vote buying and multi-party competition. Electoral factors, however, cannot explain the patterns observed in China’s single-party dictatorship. This study highlights two nested factors that influence public employment in China: party co-optation and personal clientelism. As a collective body, the ruling party seeks to co-opt restive ethnic minorities by expanding cadre recruitment in hinterland provinces. Within the party, individual elites seek to expand their own networks of power by appointing clients to office. The central government’s professed objective of streamlining bureaucracy is in conflict with the party’s co-optation goal and individual elites’ clientelist interest. As a result, the size of public employment has inflated during the reform period despite top-down mandates to downsize bureaucracy.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/116599/1/Ang, Cooptation & Clientelism, posted 2016-01.pdfDescription of Ang, Cooptation & Clientelism, posted 2016-01.pdf : First Onlin
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