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181.
Anania C Gustafsson T Hua X Su J Vikström M de Faire U Heimbürger M Jogestrand T Frostegård J 《Arthritis research & therapy》2010,12(6):R214
Introduction
The risk of cardiovascular disease (CVD) and atherosclerosis is reported to be increased in systemic lupus erythematosus (SLE). We recently reported a negative association between natural IgM-antibodies against phosphorylcholine (anti-PC) in the general population, high anti-PC levels leading to decreased atherosclerosis development and low levels to increased risk of CVD. Potential mechanisms include anti-inflammatory properties and inhibition of uptake of oxidized low density lipoprotein (LDL) in macrophages. The objective herein was to study atherosclerosis in SLE in detail and in relation to traditional and non-traditional risk factors. 相似文献182.
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The Genome-wide Patterns of Variation Expose Significant Substructure in a Founder Population 总被引:2,自引:0,他引:2 下载免费PDF全文
Eveliina Jakkula Karola Rehnstrm Teppo Varilo Olli P.H. Pietilinen Tiina Paunio Nancy L. Pedersen Ulf deFaire Marjo-Riitta Jrvelin Juha Saharinen Nelson Freimer Samuli Ripatti Shaun Purcell Andrew Collins Mark J. Daly Aarno Palotie Leena Peltonen 《American journal of human genetics》2008,83(6):787-794
Although high-density SNP genotyping platforms generate a momentum for detailed genome-wide association (GWA) studies, an offshoot is a new insight into population genetics. Here, we present an example in one of the best-known founder populations by scrutinizing ten distinct Finnish early- and late-settlement subpopulations. By determining genetic distances, homozygosity, and patterns of linkage disequilibrium, we demonstrate that population substructure, and even individual ancestry, is detectable at a very high resolution and supports the concept of multiple historical bottlenecks resulting from consecutive founder effects. Given that genetic studies are currently aiming at identifying smaller and smaller genetic effects, recognizing and controlling for population substructure even at this fine level becomes imperative to avoid confounding and spurious associations. This study provides an example of the power of GWA data sets to demonstrate stratification caused by population history even within a seemingly homogeneous population, like the Finns. Further, the results provide interesting lessons concerning the impact of population history on the genome landscape of humans, as well as approaches to identify rare variants enriched in these subpopulations. 相似文献
185.
Werner Mstle Ulrich Link Wolfgang Witschel Ulf Thewalt Thomas Weber Manfred Rothe 《Biopolymers》1991,31(6):735-744
The title compound represents the smallest member of cyclic proline peptides corresponding to the general formula c(DDLL-Pro4)n with a strictly D,D,L,L double-alternating sequence of the chiral amino acid residues. The cyclopeptides with n greater than or equal to 2 could be synthesized from both DDLL-Pro4 (1) and DLLD-Pro4 (2). The cyclic monomer (n = 1) resulted only from 2, whereas not even a trace could be found by cyclization of 1. The peptide exists in a strongly strained Ci symmetrical conformation (x-ray analysis) with alternating cis and trans peptide bonds (ctct form I). The cis peptide bonds deviate from planarity (omega = 22 degrees); two of the pyrrolidine rings show a "South" conformation (phi = -94 degrees), whereas the other residues exhibit C alpha-endo puckering (phi = -124 degrees). Two of the psi angles surprisingly occur at +41 degrees (anti-cis'), the others are located in the trans' region. A quantitative ring opening occurs with trifluoroacetic acid at room temperature. In solution the existence of an isomeric ctcc sequence (form Ia) is indicated. Dreiding model studies also suggested a favorable conformation with a tctc sequence (form II). Consequently, we performed molecular mechanics calculations, based on the CHARMM force field and semiempirical quantum mechanical AM1 calculations (MOPAC program). Pronounced differences in the backbone parameters were found using these two methods. However, the theoretical studies evidenced the experimentally obtained differences in the cyclization tendencies of the linear precursors. 相似文献
186.
Hubregtse T Neeleman E Maschmeyer T Sheldon RA Hanefeld U Arends IW 《Journal of inorganic biochemistry》2005,99(5):1264-1267
The ligand of the naturally occurring vanadium compound amavadin found in Amanita muscaria, (2S, 2'S)-N-hydroxyimino-2,2'-dipropionic acid (1), was synthesized stereoselectively in two steps with 43% overall yield. After complexation of this ligand to vanadyl acetate, amavadin was isolated in quantitative yield. Due to the chirality at vanadium amavadin consists of a mixture of delta and lambda diastereoisomers. Directly after its synthesis, the delta to lambda ratio of amavadin is 2.27 and it decreases to 0.80 after equilibrium has been reached. During this epimerization the optical rotation for V[(2S,2'S)-N-hydroxyimino-(2,2')-dipropionate]2 (=amavadin) changes from [alpha](D)25 = +36 degrees to +114.0 degrees (c = 0.5, H2O). For V[(2R,2'R)-N-hydroxyimino-(2,2')-dipropionate] the optical rotation changes from [alpha](D)25 = -36 degrees to -113.2 degrees (c = 0.5, H2O). 相似文献
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Beisvåg V Kauffmann A Malone J Foy C Salit M Schimmel H Bongcam-Rudloff E Landegren U Parkinson H Huber W Brazma A Sandvik AK Kuiper M 《BioTechniques》2011,50(1):27-31
While minimum information about a microarray experiment (MIAME) standards have helped to increase the value of the microarray data deposited into public databases like ArrayExpress and Gene Expression Omnibus (GEO), limited means have been available to assess the quality of this data or to identify the procedures used to normalize and transform raw data. The EMERALD FP6 Coordination Action was designed to deliver approaches to assess and enhance the overall quality of microarray data and to disseminate these approaches to the microarray community through an extensive series of workshops, tutorials, and symposia. Tools were developed for assessing data quality and used to demonstrate how the removal of poor-quality data could improve the power of statistical analyses and facilitate analysis of multiple joint microarray data sets. These quality metrics tools have been disseminated through publications and through the software package arrayQualityMetrics. Within the framework provided by the Ontology of Biomedical Investigations, ontology was developed to describe data transformations, and software ontology was developed for gene expression analysis software. In addition, the consortium has advocated for the development and use of external reference standards in microarray hybridizations and created the Molecular Methods (MolMeth) database, which provides a central source for methods and protocols focusing on microarray-based technologies. 相似文献
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Pain DJ Green RE Giebetaing B Kozulin A Poluda A Ottosson U Flade M Hilton GM 《Oecologia》2004,138(2):168-174
Understanding the links between breeding and wintering areas of migratory species has important ecological and conservation implications. Recently, stable isotope technology has been used to further our understanding. Stable isotope ratios vary geographically with a range of biogeochemical factors and isotope profiles in organisms reflect those in their food and environment. For inert tissues like feathers, isotope profiles reflect the environment in which they were formed. Following large-scale habitat destruction, the globally threatened aquatic warbler Acrocephalus paludicola has a fragmented breeding population across central Europe, largely in Belarus, Poland and Ukraine. The species sub-Saharan African wintering grounds have not yet been discovered, and this significantly hampers conservation efforts. Aquatic warblers grow their flight feathers on their wintering grounds, and we analysed stable isotope ratios (15N, 13C, D) in rectrices of adults from six main breeding sites (subpopulations) across Europe to determine whether different breeding subpopulations formed a single mixed population on the wintering grounds. 15N varies considerably with dietary trophic level and environmental factors, and D with the D in rainfall; neither varied between aquatic warbler subpopulations. Uniform feather 15N signatures suggest no major variation in dietary trophic level during feather formation. High variance and inter-annual differences in mean D values hinder interpretation of these data. Significant differences in mean 13C ratios existed between subpopulations. We discuss possible interpretations of this result, and consider differences in moulting latitude of different subpopulations to be the most parsimonious. 13C in plants and animals decreases with latitude, along a steep gradient in sub-Saharan Africa. Birds from the most north-westerly breeding subpopulation (Karsibor, Poland) had significantly lower variance in 13C and 15N than birds from all other sites, suggesting either that birds from Karsibor are less geographically dispersed during moult, or moult in an area with less isotopic heterogeneity. Mean 13C signatures from winter-grown feathers of different subpopulations were positively correlated with the latitude and longitude of breeding sites, suggesting a strong relationship between European breeding and African winter moulting latitudes. The use of stable isotopes provides novel insights into migratory connectivity and migration patterns in this little-known threatened species. 相似文献