bluuebunny/crossref_metadata_2025_split huggingface dataset:
Cutting Edge: Extracellular Signal-Related Kinase Is Not Required for Negative Selection of Developing T Cells
Authors: McGargill Maureen A. , Ch'en Irene L. , Katayama Carol D. , Pagès Gilles , Pouysségur Jacques , Hedrick Stephen M. 
Published: October 2009

Abstract
Signals initiated through the TCR during development can result in either survival and differentiation or cell death. High affinity signals that induce death elicit a robust yet transient activation of signaling pathways, including Erk, whereas low affinity ligands, which promote survival, generate a gradual and weaker activation of the same pathways. It was recently demonstrated that Erk localizes to distinct cellular locations in response to high and low affinity ligands. Although a requirement for Erk in positive selection is well established, its role in negative selection is controversial and, thus, the importance of Erk relocalization during development is not understood. In this study, we examined the role of Erk in negative selection using mice that are genetically deficient in both Erk1 and Erk2 in T cells. Results from three different models reveal that thymocyte deletion remains intact in the absence of Erk.
Multilayer Hybrid Films Consisting of Alternating Graphene and Titania Nanosheets with Ultrafast Electron Transfer and Photoconversion Properties
Authors: Manga Kiran Kumar , Zhou Yong , Yan Yongli , Loh Kian Ping 
Published: October 2009

AbstractAlternating graphene (G) and titania (Ti0.91O2) multilayered nanosheets are fabricated using layer‐by‐layer electrostatic deposition followed by UV irradiation. Successful assemblies of graphene oxide (GO) and titania nanosheets in sequence with polyethylenimine as a linker is confirmed by UV–vis absorption and X‐ray diffraction. Photocatalytic reduction of GO into G can be achieved upon UV irradiation. Ultrafast photocatalytic electron transfer between the titania and graphene is demonstrated using femtosecond transient absorption spectroscopy. Efficient exciton dissociation at the interfaces coupled with cross‐surface charge percolation allows efficient photocurrent conversion in the multilayered Ti0.91O2/G films.
Preferential recruitment of interferon‐γ–expressing TH17 cells in multiple sclerosis
Authors: Kebir Hania , Ifergan Igal , Alvarez Jorge Ivan , Bernard Monique , Poirier Josée , Arbour Nathalie , Duquette Pierre , Prat Alexandre 
Published: October 2009

AbstractObjectiveThere is substantial evidence supporting the role of interferon (IFN)‐γ–producing T helper (TH) 1 and interleukin (IL)‐17–expressing TH17 lymphocytes in multiple sclerosis (MS) and its animal model, experimental allergic encephalomyelitis (EAE). However, to date little is known about the potential cooperative interplay between these 2 cytokines. In the current study, we sought to evaluate the frequency of IFN‐γ–expressing TH17 lymphocytes in MS and EAE, and study their recruitment into the central nervous system (CNS).MethodsHuman TH17 lymphocytes were expanded in vitro from the blood of healthy controls and relapsing MS patients using IL‐23. Immune cell migration to the CNS was assessed in vitro with primary cultures of human blood–brain barrier (BBB)‐derived endothelial cells, and in vivo in EAE mice.ResultsWe demonstrate that in response to IL‐23, human memory lymphocytes expand into a TH17 phenotype, with a subpopulation of cells simultaneously expressing IFN‐γ and IL‐17. We note that lymphocytes obtained from the blood of relapsing MS patients have an increased propensity to expand into IFN‐γ–producing TH17 cells and identify numerous T lymphocytes coexpressing IL‐17 and IFN‐γ in brain tissue of MS patients. We also find lymphocytes expressing both the TH1‐ and the TH17‐associated transcription factors RORγt and T‐bet, in situ and in vitro. We further provide in vitro and in vivo evidence that IFN‐γ+ TH17 lymphocytes preferentially cross the human BBB and accumulate in the CNS of mice during the effector phase of EAE.InterpretationOur data underscore the involvement of IFN‐γ+ TH17 lymphocytes in the pathology of MS and EAE and their preferential recruitment into the CNS during inflammatory events. Ann Neurol 2009;66:390–402
Student laboratory presentations as a learning tool in anatomy education
Authors: Chollet Madeleine B. , Teaford Mark F. , Garofalo Evan M. , DeLeon Valerie B. 
Published: October 2009

AbstractPrevious studies have shown that anatomy students who complete oral laboratory presentations believe they understand the material better and retain it longer than they otherwise would if they only took examinations on the material; however, we have found no studies that empirically test such outcomes. The purpose of this study was to assess the effectiveness of oral presentations through comparisons with other methods of assessment, most notably, examination performance. Specifically, we tested whether students (n = 256) performed better on examination questions on topics covered by their oral presentations than on other topics. Each student completed two graded, 12‐minute laboratory presentations on two different assigned topics during the course and took three examinations, each of which covered a third of the course material. Examination questions were characterized by type (memorization, pathway, analytical, spatial). A two‐way repeated measures analysis of variance revealed that students performed better on topics covered by their presentations than on topics not covered by their presentations (P < 0.005), regardless of presentation grade (P > 0.05) and question type (P > 0.05). These results demonstrate empirically that oral presentations are an effective learning tool. Anat Sci Educ 2: 260–264, 2009. © 2009 American Association of Anatomists.
Demonstrating and eliminating the aggregation effect in physical skill tasks
Authors: Stone Eric R. , Rittmayer Ashley D. , Murray Nicole T. , McNiel J. Murray 
Published: October 2009

AbstractConfidence judgments can be elicited in multiple ways. One of these procedures is to provide confidence judgments regarding each of a number of cases (individual judgments). A second procedure is to provide confidence judgments about a set of items (an aggregate judgment). Much research has demonstrated an aggregation effect—that individual judgments are more confident than aggregate judgments—within the cognitive knowledge domain. However, this effect has not previously been investigated with physical performance skill tasks. In three experiments, participants gave individual and aggregate judgments regarding the number of successful tosses they would make in either a ring toss, ping‐pong toss, or basketball toss task. In keeping with the aggregation effect, individual judgments were more confident than were aggregate judgments of success. Additionally, we eliminated the aggregation effect in Experiments 2 and 3 by employing a case‐specific base rate manipulation. Consistent with previous research with cognitive tasks, these results suggest that individual confidence judgments for physical skill tasks are determined primarily by characteristics associated with the individual case to be judged, whereas aggregate confidence judgments are determined by a more general evaluation of one's ability in the domain. Copyright © 2009 John Wiley & Sons, Ltd.
Structural stability and aggregation behavior of the VEALYL peptide derived from human insulin: A molecular dynamics simulation study
Authors: Lin Yeh‐Fon , Zhao Jian‐Hua , Liu Hsuan‐Liang , Liu Kung‐Tien , Chen Jenn‐Tzong , Tsai Wei‐Bor , Ho Yih 
Published: October 2009

AbstractThe VEALYL peptide from B chain (residues 12–17) of insulin has been shown to form amyloid‐like fibrils. Recently, the atomic structure of the VEALYL oligomer has been determined by X‐ray microcrystallography and reveals a dry, tightly self‐complementing structure between the neighboring β‐sheet layers, termed as “steric zipper.” In this study, several molecular dynamics simulations with all‐atom explicit water were conducted to investigate the structural stability and aggregation behavior of the VEALYL peptide with various sizes and its single glycine replacement mutations. The results of our single‐layer models showed that the structural stability of the VEALYL oligomers increases significantly with increasing the number of β‐strands. We further suggested that the minimal nucleus seed for VEALYL fibril formation could be as small as three or four peptides. Our results also revealed that the hydrophobic interaction between E2 and Y5 plays an important role in stabilizing the adjacent β‐strands within the same layer, whereas the hydrophobic steric zipper formed via the side chains of V1, A3, L4, Y5, and L6 locks the two neighboring β‐sheet layers together. Mutation simulations showed that the substitution of a single glycine residue directly disrupts this steric zipper, resulting in the destabilization of the VEALYL oligomers. This study provides the atomic insights into understanding the aggregation behavior of the VEALYL peptide. It may also be helpful for designing new or modified capping peptides able to break the driving force for aggregation and to prevent the fibril formation of the VEALYL peptide and the insulin protein. © 2010 Wiley Periodicals, Inc. Biopolymers (Pept Sci) 94: 269–278, 2010.This article was originally published online as an accepted preprint. The “Published Online” date corresponds to the preprint version. You can request a copy of the preprint by emailing the Biopolymers editorial office at biopolymers@wiley.com
Thermal stability and conformational structure of salmon calcitonin in the solid and liquid states
Authors: Lee Ting‐Huei , Cheng Wen‐Ting , Lin Shan‐Yang 
Published: October 2009

AbstractSalmon calcitonin (sCT) was selected as a model protein drug for investigating its intrinsic thermal stability and conformational structure in the solid and liquid states by using a Fourier transform infrared (FT‐IR) microspectroscopy with or without utilizing thermal analyzer. The spectral correlation coefficient (r) analysis between two second‐derivative IR spectra was applied to quantitatively estimate the structural similarity of sCT in the solid state before and after different treatments. The thermal FT‐IR microspectroscopic data clearly evidenced that sCT in the solid state was not effected by temperature and had a thermal reversible property during heating–cooling process. Moreover, the high r value of 0.973 or 0.988 also evidenced the structural similarity of solid‐state sCT samples before and after treatments. However, sCT in H2O exhibited protein instability and thermal irreversibility after incubation at 40°C. The temperature‐induced conformational changes of sCT in H2O was occurred to transform the α‐helix/random coil structures to β‐sheet structure and also resulted in the formation of intramolecular and intermolecular β‐sheet structures. © 2009 Wiley Periodicals, Inc. Biopolymers 93: 200–207, 2010.This article was originally published online as an accepted preprint. The “Published Online” date corresponds to the preprint version. You can request a copy of the preprint by emailing the Biopolymers editorial office at biopolymers@wiley.com
Investigating the role of native propionyl‐CoA and methylmalonyl‐CoA metabolism on heterologous polyketide production in Escherichia coli
Authors: Zhang Haoran , Boghigian Brett A. , Pfeifer Blaine A. 
Published: October 2009

Abstract6‐Deoxyerythronolide B (6dEB) is the macrocyclic aglycone precursor of the antibiotic natural product erythromycin. Heterologous production of 6dEB in Escherichia coli was accomplished, in part, by designed over‐expression of a native prpE gene (encoding a propionyl‐CoA synthetase) and heterologous pcc genes (encoding a propionyl‐CoA carboxylase) to supply the needed propionyl‐CoA and (2S)‐methylmalonyl‐CoA biosynthetic substrates. Separate E. coli metabolism includes three enzymes, Sbm (a methylmalonyl‐CoA mutase), YgfG (a methylmalonyl‐CoA decarboxylase), and YgfH (a propionyl‐CoA:succinate CoA transferase), also involved in propionyl‐CoA and methylmalonyl‐CoA metabolism. In this study, the sbm, ygfG, and ygfH genes were individually deleted and over‐expressed to investigate their effect on heterologous 6dEB production. Our results indicate that the deletion and over‐expression of sbm did not influence 6dEB production; ygfG over‐expression reduced 6dEB production by fourfold while ygfH deletion increased 6dEB titers from 65 to 129 mg/L in shake flask experiments. It was also found that native E. coli metabolism could support 6dEB biosynthesis in the absence of exogenous propionate and the substrate provision pcc genes. Lastly, the effect of the ygfH deletion was tested in batch bioreactor cultures in which 6dEB titers improved from 206 to 527 mg/L. Biotechnol. Bioeng. 2010; 105: 567–573. © 2009 Wiley Periodicals, Inc.
Determination of dopamine, serotonin, and their metabolites in pediatric cerebrospinal fluid by isocratic high performance liquid chromatography coupled with electrochemical detection
Authors: Hubbard K. Elaine , Wells Amy , Owens Thandranese S. , Tagen Michael , Fraga Charles H. , Stewart Clinton F. 
Published: October 2009

AbstractA method to rapidly measure dopamine (DA), dihydroxyindolphenylacetic acid, homovanillic acid, serotonin (5‐HT) and 5‐hydroxyindoleacetic acid concentrations in cerebrospinal fluid (CSF) has not yet been reported. A rapid, sensitive, and specific HPLC method was therefore developed using electrochemical detection. CSF was mixed with an antioxidant solution prior to freezing to prevent neurotransmitter degradation. Separation of the five analytes was obtained on an ESA MD‐150 × 3.2 mm column with a flow rate of 0.37 mL/min and an acetonitrile–aqueous (5 : 95, v/v) mobile phase with 75 mM monobasic sodium phosphate buffer, 0.5 mM EDTA, 0.81 mM sodium octylsulfonate and 5% tetrahydrofuran. The optimal electrical potential settings were: guard cell +325 mV, E1 −100 mV and E2 +300 mV. Within‐day and between‐day precisions were <10% for all analytes and accuracies ranged from 91.0 to 106.7%. DA, 5‐HT, and their metabolites were stable in CSF with antioxidant solution at 4°C for 8 h in the autoinjector. This method was used to measure neurotransmitters in CSF obtained from children enrolled on an institutional medulloblastoma treatment protocol. Copyright © 2009 John Wiley & Sons, Ltd.
Bioanalysis of pentoxifylline and related metabolites in plasma samples through LC‐MS/MS
Authors: Sora Daniela Iuliana , Cristea Elena , Albu Florin , David Victor , Medvedovici Andrei 
Published: October 2009

AbstractAnalytical aspects related to the assay of pentoxifylline (PTX), lisofylline (M1) and carboxypropyl dimethylxanthine (M5) metabolites are discussed through comparison of two alternative analytical methods based on liquid chromatography separation and atmospheric pressure electrospray ionization tandem mass spectrometry detection. One method is based on a ‘pure’ reversed‐phase liquid chromatography mechanism, while the second one uses the additional polar interactions with embedded amide spacers linking octadecyl moieties to the silicagel surface (C‐18 Aqua stationary phase). In both cases, elution is isocratic. Both methods are equally selective and allows separation of unknowns (four species associated to PTX, two species associated to M1) detected through specific mass transitions of the parent compounds and owning respective structural confirmation. Plasma concentration–time patterns of these compounds follow typical metabolic profiles. It has been advanced that in‐vivo formation of conjugates of PTX and M1 is possible, such compounds being cleaved back to the parent ones within the ion source. The first method was associated with a sample preparation procedure based on plasma protein precipitation by strong organic acid addition. The second method used protein precipitation by addition of a water miscible organic solvent. Both analytical methods were fully validated and used to assess bioequivalence between a prolonged release generic formulation and the reference product, under multidose and single dose approaches. Copyright © 2009 John Wiley & Sons, Ltd.
Highly sensitive determination of Schisandrin and Schisandrin B in plasma of rats after administration of Wurenchun (Fructus Schisandrae Chinensis Extracts) preparations by LC‐ESI‐MS/MS
Authors: Tang Jingling , Shao Bing , Liu Yan , Liu Hongmei , Ji Hongyu , Zhu Daling , Wu Linhua 
Published: October 2009

AbstractA sensitive and specific method based on liquid chromatography‐tandem mass spectrometry using electrospray ionization (LC‐ESI‐MS/MS) has been developed for the determination of Schisandrin and Schisandrin B in rat plasma. A 100 μL plasma sample was extracted by methyl tert‐butyl ether after spiking the samples with nimodipine (internal standard) and performed on an XTerra®MS‐C18 column (150 mm × 2.1 mm, 3.5 μm) with the mobile phase of acetonitrile–water–formic acid (80:20:0.2, v/v) at a flow rate of 0.2 mL/min in a run time of 8.5 min. The lower limit of quantification of the method was 40 ng/mL for Schisandrin and 20 ng/mL for Schisandrin B. The method showed reproducibility with intra‐day and inter‐day precision of less than 13.8% RSD, as well as accuracy, with inter‐ and intra‐assay accuracies between 93.5 and 107.2%. Finally, the LC‐ESI‐MS/MS method was successfully applied to study the pharmacokinetics of Schisandrin and Schisandrin B in rats after administration of Wurenchun commercial formulations to rats. Copyright © 2009 John Wiley & Sons, Ltd.
The impact of hematocrit drop on long‐term survival after cardiac catheterization: Insights from the Dartmouth Dynamic Registry
Authors: Leung Calvin C. , Sabir Sajjad A. , Brown Jeremiah R. , Sidhu Mandeep S. , Kaplan Aaron V. , Jayne John E. , Friedman Bruce J. , Hettleman Bruce D. , Niles Nathaniel W. , DeVries James T. , Robb John F. , Malenka David J. , Thompson Craig A. 
Published: October 2009

AbstractBackground: The long‐term prognostic implication of post‐procedural hematocrit drops in patients undergoing cardiac catheterization outside the clinical trial setting is not well defined. Methods: Data was prospectively collected from 12,661 patients undergoing diagnostic or interventional cardiac catheterization between July 1998 and July 2006. Patients were divided into three cohorts based upon the degree of hematocrit change: drop greater than 6, drop between 3 and 6, and drop less than 3. In‐hospital major adverse events, 30‐day mortality, and long‐term all‐cause mortality were recorded. Results: Patients with larger reductions in hematocrit were more likely to be older, female, and have a higher baseline hematocrit, present with acute myocardial infarction, develop cardiogenic shock, require emergent catheterization, develop retroperitoneal bleeds and large hematomas, receive transfusions, have longer index hospitalizations, develop subacute stent thrombosis, and have higher 30‐day and long‐term mortality. An increase in long‐term mortality was observed with progressive hematocrit drop. This finding is largely driven by early (30 day) mortality, as trends were no longer significant after rezeroing mortality. Hematocrit drop was not an independent risk factor for 30‐day mortality. Transfusion and low baseline hematocrit were identified as independent predictors of near and long‐term mortality. Conclusions: Periprocedural bleeding, defined by hematocrit drop, is associated with increased near‐term and long‐term mortality in patients undergoing diagnostic and therapeutic cardiac catheterization procedures. Long‐term mortality is largely driven by up front 30‐day mortality. Hematocrit drop was not an independent predictor for near‐term mortality. Transfusion and low baseline hematocrit were independent predictors for near and long‐term mortality. © 2009 Wiley‐Liss, Inc.
Multicentre experience with MGuard™ net protective stent in ST‐elevation myocardial infarction: Safety, feasibility, and impact on myocardial reperfusion
Authors: Piscione Federico , Danzi Gian Battista , Cassese Salvatore , Esposito Giovanni , Cirillo Plinio , Galasso Gennaro , Rapacciuolo Antonio , Leosco Dario , Briguori Carlo , Varbella Ferdinando , Tuccillo Bernardino , Chiariello Massimo 
Published: October 2009

AbstractObjective: To report, for the first time, angiographic and ECG results as well as in‐hospital and 1‐month clinical follow‐up, after MGuard net protective stent (Inspire‐MD, Tel‐Aviv, Israel—MGS) implantation in consecutive, not randomized, STEMI patients undergoing primary or rescue PCI. Background: Distal embolization may decrease coronary and myocardial reperfusion after percutaneous coronary intervention (PCI), in ST‐elevation myocardial infarction (STEMI) setting. Methods: One‐hundred consecutive patients underwent PCI, with MGS deployment for STEMI, in five different high‐volume PCI centres. Sixteen patients presented cardiogenic shock at admission. Results: All patients underwent successful procedures: mean TIMI flow grade and mean corrected TIMI frame count—cTFC(n)—improved from baseline values to 2.85 ± 0.40 and to 17.20 ± 10.51, respectively, with a mean difference in cTFC(n) between baseline and postprocedure of 46.88 ± 31.86. High‐myocardial blush grade (90% MBG 3; 10% MBG 2) was also achieved in all patients. Sixty minutes post‐PCI, a high rate (90%) of complete (≥70%) ST‐segment resolution was achieved. At in‐hospital follow‐up, seven deaths occurred: noteworthy, 5 of 16 patients with cardiogenic shock at admission died. After hospital discharge, no Major Adverse Cardiac Events have been reported up to 30‐day follow‐up. Conclusions: MGS might represent a safe and feasible option for PCI in STEMI patients, providing high perfusional and ECG improvement. Further randomized trials comparing this strategy with the conventional one are needed in the near future to assess the impact on clinical practice of this strategy. © 2009 Wiley‐Liss, Inc.
Endovascular therapy for a ruptured popliteal aneurysm
Authors: Lamoca Luis Miguel Izquierdo , Alerany Montserrat Blanch , Hernando Luis Leiva 
Published: October 2009

AbstractIntroduction: We here present a case of a ruptured giant popliteal artery aneurysm (PAA) successfully treated with endovascular surgery. Case Report: A 88‐year‐old male presented with left limb massive swelling and pain. His general status was critical with acute respiratory insufficiency. CT scan showed massive haematoma in the thigh and a PAA of 9.1 cm in diameter. Urgent endovascular repair was successfully performed under local anaesthesia. Nevertheless, patient died, on second postoperatory day, because of respiratory failure. Discussion: Up to 50% of PAA present with acute limb ischaemia is due to thrombosis or distal embolization. Rupture is an uncommon complication affecting less than 3% of PAA. Diameter greater than 2 cm or mural thrombosis are indications for elective intervention. Open surgical repair is the first treatment option. In selected patients, endovascular repair can be performed. Midterm results of this technique, recently reported, are comparable to open repair. © 2009 Wiley‐Liss, Inc.