bluuebunny/crossref_metadata_2025_split huggingface dataset:
B-type natriuretic peptide release and left ventricular filling pressure assessed by echocardiographic study after subarachnoid hemorrhage: a prospective study in non-cardiac patients
Authors: Meaudre Eric , Jego Christophe , Kenane Nadia , Montcriol Ambroise , Boret Henry , Goutorbe Philippe , Habib Gilbert , Palmier Bruno 
Published: May 2009

Abstract
Introduction
Serum B-type natriuretic peptide (BNP) is frequently elevated after subarachnoid hemorrhage (SAH), but whether this high BNP level is related to transient elevation of left ventricular filling pressure (LVFP) is unknown. However, in patients with preexistent cardiac pathologies, it is impossible to differentiate between BNP elevation caused by chronic cardiac abnormalities and BNP related to acute neurocardiac injury.

Methods
All adult patients with SAH admitted to our intensive care unit were eligible. Patients were excluded for the following reasons: admission >48 hours after aneurysm rupture, pre-existing hypertension, or cardiac disease. Levels of BNP and cardiac troponin Ic were measured daily for 7 days. Echocardiography was performed by a blinded cardiologist on days 1, 2, and 7. Doppler signals from the mitral inflow, tissue Doppler, and the color M-mode–derived flow propagation velocity (FPV) were obtained to assess echo-estimated LVFP.

Results
During a 3-year period, sixty-six consecutive patients with SAH were admitted. Thirty one patients were studied. The BNP level was >100 ng/L in 25 patients (80%) during the first 3 days, with a peak on day 2 (median, 126 ng/L) followed by a gradual decrease (median variation days 1 to 7, 70%). All patients had an ejection fraction >50%. Early transmitral velocity/tissue Doppler mitral annular early diastolic velocity was low: 5.4 (± 1.5) on day 1, 5.8 (± 1.2) on day 2, and 5.1 (± 0.9) on day 7. Early transmitral velocity/FPV was also low: 1.27 (± 0.4), 1.25 (± 0.3), and 1.1 (± 0.2) on days 1, 2, and 7, respectively. Cardiac troponin Ic levels ranged from 0 to 3.67 μg/L and were correlated with BNP (r = 0.63, P < 0.01).

Conclusions
BNP rises gradually over two days and return to normal within a week after SAH. Its release is associated with myocardial necrosis, but is unrelated to elevated LVFP assessed by echocardiography.
Whole genome sequencing of a natural recombinant Toxoplasma gondiistrain reveals chromosome sorting and local allelic variants
Authors: Bontell Irene Lindström , Hall Neil , Ashelford Kevin E , Dubey JP , Boyle Jon P , Lindh Johan , Smith Judith E 
Published: May 2009

Abstract
Background
Toxoplasma gondii is a zoonotic parasite of global importance. In common with many protozoan parasites it has the capacity for sexual recombination, but current evidence suggests this is rarely employed. The global population structure is dominated by a small number of clonal genotypes, which exhibit biallelic variation and limited intralineage divergence. Little is known of the genotypes present in Africa despite the importance of AIDS-associated toxoplasmosis.

Results
We here present extensive sequence analysis of eight isolates from Uganda, including the whole genome sequencing of a type II/III recombinant isolate, TgCkUg2. 454 sequencing gave 84% coverage across the approximate 61 Mb genome and over 70,000 single nucleotide polymorphisms (SNPs) were mapped against reference strains. TgCkUg2 was shown to contain entire chromosomes of either type II or type III origin, demonstrating chromosome sorting rather than intrachromosomal recombination. We mapped 1,252 novel polymorphisms and clusters of new SNPs within coding sequence implied selective pressure on a number of genes, including surface antigens and rhoptry proteins. Further sequencing of the remaining isolates, six type II and one type III strain, confirmed the presence of novel SNPs, suggesting these are local allelic variants within Ugandan type II strains. In mice, the type III isolate had parasite burdens at least 30-fold higher than type II isolates, while the recombinant strain had an intermediate burden.

Conclusions
Our data demonstrate that recombination between clonal lineages does occur in nature but there is nevertheless close homology between African and North American isolates. The quantity of high confidence SNP data generated in this study and the availability of the putative parental strains to this natural recombinant provide an excellent basis for future studies of the genetic divergence and of genotype-phenotype relationships.
Pivotal Advance: CEACAM1 is a negative coreceptor for the B cell receptor and promotes CD19-mediated adhesion of B cells in a PI3K-dependent manner
Authors: Lobo Elizabeth O , Zhang Zhifang , Shively John E 
Published: May 2009

Abstract
CEACAM1 coreceptor for the B-cell receptor inhibits activated B-cells by recruiting SHP-1 to its phosphorylated ITIMs, preventing phosphorylation of the large subunit of PI-3K.
Upon antigen binding, the BCR transduces a signal culminating in proliferation or in AICD of the B cell. Coreceptor engagement and subsequent modification of the BCR signal pathway are mechanisms that guide the B cell to its appropriate fate. For example, in the absence of coreceptor engagement, anti-sIgM antibodies induce apoptosis in the human Daudi B cell lymphoma cell line. ITIM-bearing B cell coreceptors that potentially may act as negative coreceptors include FcRγIIb, CD22, CD72, and CEACAM1 (CD66a). Although the role of CEACAM1 as an inhibitory coreceptor in T cells has been established, its role in B cells is poorly defined. We show that anti-sIgM antibody and PI3K inhibitor LY294002-induced apoptosis are reduced significantly in CEACAM1 knock-down clones compared with WT Daudi cells and that anti-sIgM treatment induced CEACAM1 tyrosine phosphorylation and association with SHP-1 in WT cells. In contrast, treatment of WT Daudi cells with anti-CD19 antibodies does not induce apoptosis and has reduced tyrosine phosphorylation and SHP-1 recruitment to CEACAM1. Thus, similar to its function in T cells, CEACAM1 may act as an inhibitory B cell coreceptor, most likely through recruitment of SHP-1 and inhibition of a PI3K-promoted activation pathway. Activation of B cells by anti-sIgM or anti-CD19 antibodies also leads to cell aggregation that is promoted by CEACAM1, also in a PI3K-dependent manner.
Resistin Is More Abundant in Liver Than Adipose Tissue and Is Not Up-Regulated by Lipopolysaccharide
Authors: Szalowska Ewa , Elferink Marieke G. L. , Hoek Annemiek , Groothuis Geny M. M. , Vonk Roel J. 
Published: May 2009

Context: Resistin is an adipokine correlated with inflammatory markers and is predictive for cardiovascular diseases. There is evidence that serum resistin levels are elevated in obese patients; however, the role of resistin in insulin resistance and type 2 diabetes remains controversial.
Objective: We addressed the question of whether inflammation may induce expression of resistin in organs involved in regulation of total body energy metabolism, such as liver and adipose tissue (AT).
Methods: Human liver tissue, sc AT, and omentum were cultured in the absence/presence of lipopolysaccharide (LPS). The resistin and cytokine mRNA and protein expression levels were determined by real-time PCR, ELISA, and Multiplex Technology, respectively. The localization of resistin in human liver was analyzed by immunohistochemistry.
Results: Resistin gene and protein expression was significantly higher in liver than in AT. Exposure of human AT and liver tissue in culture to LPS did not alter resistin concentration; however, concentrations of IL-1β, IL-6, and TNFα were significantly increased in these tissues. In liver, resistin colocalizes with markers for Kupffer cells, for a subset of endothelial and fibroblast-like cells.
Conclusions: High level of resistin gene and protein expression in liver compared to AT implies that resistin should not be considered only as an adipokine in humans. LPS-induced inflammation does not affect resistin protein synthesis in human liver and AT. This suggests that elevated serum resistin levels are not indicative for inflammation of AT or liver in a manner similar to known inflammatory markers such as IL-1β, IL-6, or TNFα.
Serial increased cardiac troponin T predicts mortality in asymptomatic patients treated with chronic haemodialysis
Authors: Roberts Matthew A , Hare David L , Macmillan Neil , Ratnaike Sujiva , Sikaris Ken , Ierino Francesco L 
Published: May 2009

Background A single detectable cardiac troponin predicts mortality in patients treated with dialysis. There are limited data on changes in troponin concentration over time and the clinical implications of serial troponin measurement. Methods Serial cardiac troponin T (cTnT) was assayed five times over 12 months in a prospective cohort study of patients with end-stage kidney disease treated with haemodialysis. A concentration of cTnT ≥0.04 μg/L was considered increased. Mortality and cardiovascular events were analysed by survival analysis, according to the serial troponin results. Results From 100 patients who provided a baseline sample for cTnT, 81 completed five serial measurements. The analysis of patients who completed serial cTnT measurements demonstrated that 28 patients (35%) had normal cTnT concentrations in all five samples, 20 patients (24%) had between one and four increased cTnT measurements and 33 patients (41%) had increased concentrations of cTnT in all five samples. The 1.7-y patient survival was 100%, 90% and 78% for patients with zero, one to four, or five out of five concentrations of cTnT increased, respectively ( P = 0.037), and the corresponding cardiovascular event-free survival was 100%, 91% and 78%, respectively ( P = 0.027). Conclusions Serial measurements of cTnT concentration were frequently increased in patients receiving haemodialysis. The number of abnormal measurements over time predicted mortality and cardiovascular adverse events.
MAD2 as a Key Component of Mitotic Checkpoint
Authors: Wang Li , Yin Fang , Du Yulei , Du Wenqi , Chen Bei , Zhang Yongguo , Wu Kaichun , Ding Jie , Liu Jie , Fan Daiming 
Published: May 2009

Abstract
We studied the subcellular localization of MAD2 in normal human tissues and gastric cancers. MAD2 showed nuclear and cytoplasmic localization in normal tissues such as muscle, testis, thyroid gland, cerebrum, trachea, and skin; blood vessels in some organs were also MAD2+. In normal stomach, MAD2 was expressed mainly in cytoplasm but showed nuclear staining in the majority of gastric cancers. MAD2 was significantly overexpressed in gastric cancer compared with matched adjacent tissues (P &lt; .001), and expression was related to differentiation and other clinical parameters of cancer (P &lt; .001). The cancer/adjacent normal tissue (C/N) ratio of MAD2 expression was higher than 2 and more frequently observed in patients with lymph gland metastasis (P &lt; .05) and related to cancer differentiation. Our findings suggest that the steady-state amount of MAD2 inside cells may serve as a molecular switch in mitotic checkpoint control and that the subcellular localizations of this spindle protein undergo a shift during malignant transformation. The change of MAD2 expression may be involved mainly in gastric carcinogenesis and associated with the prognosis of gastric cancer; a C/N of more than 2 may be associated with the worse prognosis for survival in gastric carcinoma.
Enhancement of dissolution rates of amorphous silica by interaction with amino acids in solution at pH 4
Authors: Kawano Motoharu , Hatta Tamao , Hwang Jinyeon 
Published: May 2009

AbstractAmino acids are present in various geochemical environments and they interact with mineral surfaces. To evaluate the effects of amino acids on mineral dissolution at pH conditions less than their isoelectric points (pI), dissolution experiments of X-ray amorphous silica in solutions containing 10.0 mmol/L of various amino acids (cysteine, asparagine, serine, tryptophan, alanine, threonine, histidine, lysine, and arginine) at pH 4 were performed. The results confirmed that basic amino acids (histidine, lysine, and arginine) produce an 8- to 8.5-fold enhancement of the rate of dissolution of amorphous silica compared with an amino acid-free control. Neutral amino acids (cysteine, asparagine, serine, tryptophan, alanine, and threonine) enhanced rates of dissolution by a factor of ∼3 to 3.5. The rate-enhancement effects of amino acids are controlled by concentrations of the amino acid’s cationic species which interact with the negatively charged >SiO− sites at the surface of the amorphous silica.
Chemostratigraphic correlation of sediments containing expandable clay minerals based on ion exchange with Cu(II) triethylenetetramine
Authors: Grygar Tomáš , Kadlec Jaroslav , Žigová Anna , Mihaljevič Martin , Nekutová Tereza , Lojka Richard , Světlík Ivo 
Published: May 2009

AbstractCopper(II) triethylenetetramine [Cu(trien)]2+ is an agent suitable for the 1-step determination of the cation exchange capacity (CEC) of many geomaterials using a procedure much less laborious than other, commonly used methods. It is also suitable for the determination of the composition of original exchangeable cations. In contrast to other common ions used for CEC analysis, the Cu(II) complex with triethylenetetramine, [Cu(trien)]2+, is specific for expandable clay minerals. The robustness of [Cu(trien)]2+ analysis was verified using reference clays, ion-exchanged reference clays, sediments, and soils. The [Cu(trien)]2+-based CEC of expandable clay minerals is not influenced significantly by ferrihydrite, goethite, manganite, birnessite, calcite, and gypsum. Birnessite, calcite, and gypsum admixtures affect the composition of the evolved cations. [Cu(trien)]2+ does not recover the entire CEC of soils (but rather that of the clay minerals only) which contain components other than clays which contribute to the CEC, e.g. soil organic matter. In a series of loess with buried paleosols and recent soils the [Cu(trien)]2+-based CEC ranged from 30 to 110% of total CEC obtained by traditional BaCl2 methods. The relative ratio of Ca to Mg, the prevailing exchangeable cations in soils and sediments in exogenic environments, are similar after [Cu(trien)]2+ and conventional BaCl2 treatments. The Ca/Mg ratio in the exchangeable fraction was used successfully for chemostratigraphic correlation of paleolacustrine sediments from a large lake in the Upper Carboniferous basins of eastern equatorial Pangaea and a series of recent flood plain sediments of the meandering Morava River in the Czech Republic. The Ca/Mg ratio obtained by [Cu(trien)]2+ analysis is proposed as a novel tool for the chemostratigraphic correlation of sediment series containing expandable clay minerals.
Crystallographic features and cleavage nanomorphology of chlinochlore: Specific applications
Authors: Valdrè Giovanni , Malferrari Daniele , Brigatti Maria Franca 
Published: May 2009

AbstractNatural and synthetic micas have been used widely as substrates to study biological systems; but, as in the case of negatively charged DNA, anionic charge repulsion may render micas a less than ideal templating surface for many biological systems. The purpose of this study was to investigate the potential for the chlorite clinoclore, which contains a positively charged interlayer octahedral sheet, to serve as a substrate for DNA adsorption. The relationships between clinochlore cleavage characteristics, in terms of nano-morphology, and surface potential are investigated, as are its average crystal chemistry and topology. That the structural features of clinochlore can be used successfully to condense, order, and self assemble complex biomolecules, such as DNA is also proven.A natural IIb-4 clinochlore [C1¯\$\end{document} symmetry, unit-cell parameters a = 0.53301(4); b = 0.92511(6); c = 1.4348(1) (nm); α = 90.420(3); β = 97.509(3); γ = 89.996(4) (°)] with chemical composition (Mg1.701Fe0.2452+Ti0.004Al0.998Cr0.0523+)Mg3(Si2.939Al1.015Fe0.0463+)O10(OH7.913F0.087)\$\end{document} was selected. The octahedral sites of the silicate layer (<M(1)−O> = 0.2080 nm and <M(2)−O> = 0.2081 nm) are equal and occupied by Mg, whereas the octahedral sites in the interlayer M(3) and M(4) (<M(3)−O> = 0.2088 nm and <M(4) − O> = 0.1939 nm) show different sizes and are mostly completely occupied by divalent (Mg2+ and Fe2+) and trivalent (Al3+) cations, respectively.The clinochlore cleaved surface is present in two forms: (1) the stripe type (0.40 nm in height, up to several micrometers long and ranging from some nanometers to a few microns in lateral size); and (2) the triangular type (0.40 nm in height). Both features may result either from interlayer sheets whose cleavage weak directions are related to the different M(3) and M(4) site occupancy, or from weak interlayer bonding along specific directions to the 2:1 layer underneath. The cleaved surface, particularly at the cleaved edges, presents high DNA affinity, which is directly related to an average positive surface and ledge potential.
The role of clay minerals in the preservation of organic matter in sediments of Qinghai Lake, NW China
Authors: Yu Bingsong , Dong Hailiang , Jiang Hongchen , LV Guo , Eberl Dennis , Li Shanying , Kim Jinwook 
Published: May 2009

AbstractThe role of saline lake sediments in preserving organic matter has long been recognized. In order to further understand the preservation mechanisms, the role of clay minerals was studied. Three sediment cores, 25, 57, and 500 cm long, were collected from Qinghai Lake, NW China, and dissected into multiple subsamples. Multiple techniques were employed, including density fractionation, X-ray diffraction, scanning and transmission electron microscopy (SEM and TEM), total organic carbon (TOC) and carbon compound analyses, and surface area determination. The sediments were oxic near the water-sediment interface, but became anoxic at depth. The clay mineral content was as much as 36.8%, consisting mostly of illite, chlorite, and halloysite. The TEM observations revealed that organic matter occurred primarily as organic matter-clay mineral aggregates. The TOC and clay mineral abundances are greatest in the mid-density fraction, with a positive correlation between the TOC and mineral surface area. The TOC of the bulk sediments ranges from 1 to 3% with the non-hydrocarbon fraction being predominant, followed by bitumen, saturated hydrocarbon, aromatic hydrocarbons, and chloroform-soluble bitumen. The bimodal distribution of carbon compounds of the saturated hydrocarbon fraction suggests that organic matter in the sediments was derived from two sources: terrestrial plants and microorganisms/algae. Depth-related systematic changes in the distribution patterns of the carbon compounds suggest that the oxidizing conditions and microbial abundance near the water-sediment interface promote degradation of labile organic matter, probably in adsorbed form. The reducing conditions and small microbial biomass deeper in the sediments favor preservation of organic matter, because of the less labile nature of organic matter, probably occurring within clay mineral-organic matter aggregates that are inaccessible to microorganisms. These results have important implications for our understanding of mechanisms of organic matter preservation in saline lake sediments.
Polarized ATR-FTIR investigation of Fe reduction in the Uley nontronites
Authors: Bzdek Bryan R. , McGuire Molly M. 
Published: May 2009

AbstractReduction of structural Fe in smectites affects the surface chemical behavior of the clay, but the underlying mechanism and changes in clay structure are still in need of investigation, particularly with respect to changes in the tetrahedral sheet. The purpose of this study was to probe changes in the tetrahedral sheet that occur when structural Fe is reduced in the Uley nontronites, NAu-1 and NAu-2, using polarized attenuated total internal reflection Fourier-transform infrared spectroscopy. Despite the differences in their structures — NAu-2 has tetrahedral Fe3+while NAu-1 does not — the changes observed in the Si-O stretching region were quite similar. Reduction results in a shift of the in-plane Si-O stretching modes to lower frequencies, while the out-of-plane Si-O stretch shifts to higher frequencies. The magnitude of these shifts is greater in NAu-2 than in NAu-1, but the crystallinity of the tetrahedral silicate sheet of NAu-2 is preserved upon reduction. In both nontronites, the orientation of the out-of-plane Si-O bond changes and becomes completely perpendicular to the basal (001) surface of the clay, indicating the formation of trioctahedral domains wherein the individual tetrahedra reorient relative to the plane of the clay layer.
Simultaneous incorporation of Cr, Zn, Cd, and Pb in the goethite structure
Authors: Kaur Navdeep , Gräfe Markus , Singh Balwant , Kennedy Brendan 
Published: May 2009

AbstractIn order to improve our understanding of how the goethite crystal structure is affected by the incorporation of metals (and by variations in the amount of the incorporation), and to review any possible synergistic and antagonistic effects of co-metals, the present investigation focused on the incorporation of multiple (di-, tri-, and tetra-) metals, i.e. Cr, Zn, Cd, and Pb, in the goethite crystallographic structure. A series of single- and multi-metal M-Cr/Zn/Cd/Pb-substituted goethites with M/(M+Fe) molar ratios = 0.10 were prepared. The general sequence of metal entry in single-metal substituted goethites was Zn = Cr > Cd > Pb and in multi-metal-substituted goethites was Zn > Cr ⩾ Cd > Pb. Simultaneous incorporation of Cr, Zn, Cd, and Pb up to 10.5 mole % was achieved in goethite. Synchrotron X-ray diffraction and extended X-ray absorption fine structure (EXAFS) techniques were employed to assess the structural characteristics of the synthesis products. Rietveld refinement of XRD data showed small changes in unit-cell parameters and Fe/M-Fe/M distances due to M substitution(s). A typical goethite-like crystalline structure remained intact, however. The unit-cell parameters were mutually, linearly correlated, though Fe/M-Fe/M distances were not, indicating that complex changes occurred at the local scale. In single-metal substituted goethites, incorporation of Cr reduced the unit-cell volume by 0.13% while that of Zn, Cd, and Pb increased it by 1.09, 3.58, and 0.56%, respectively. The changes in multi-metal-substituted goethites appeared to be the complex combination of that of the individually incorporated metals. The X-ray absorption near edge structure study of Pb-substituted goethites showed that the majority of associated Pb was Pb2+, while Pb4+ was preferred over Pb2+ in the bulk structure. Measurements by EXAFS at the Fe K-edge indicated that the Fe polyhedra contracted in the presence of Cd2+ and Pb2+, providing room for the substitution of larger cations. Measurements by EXAFS at the Cr and Cd K-edges indicated symmetric Cr/Cd polyhedra with single Cr/Cd-O distances and, at Fe and Zn K-edges and the Pb LIII-edge, indicated asymmetric polyhedra with two sets of Fe/Zn/Pb-O distances. The Zn octahedra were possibly Zn(OH)4O2, which enlarged the metal-metal corner-sharing distance to 3.86 Å. This configuration of ligands around the Zn2+ cation might occur to balance local charges. Symmetric polyhedra appeared to reduce steric strains in the structure, compared to the asymmetric polyhedra. The result was that Cr enhanced the incorporation of Zn, Cd, and Pb, while the converse was true for Zn.