bluuebunny/crossref_metadata_2025_split huggingface dataset:
Transcobalamin II 775G&gt;C polymorphism and indices of vitamin B12 status in healthy older adults
Authors: Miller Joshua W. , Ramos Marisa I. , Garrod Marjorie G. , Flynn Margaret A. , Green Ralph 
Published: October 2002

AbstractA common polymorphism (775G&gt;C) in the vitamin B12 transport protein, transcobalamin II (TCII), has been identified in which proline replaces arginine at codon 259. We determined the influence of TCII genotype on indices of B12 status, including total serum B12, the amount of B12 bound to TCII (holoTCII), methylmalonic acid, and homocysteine, in 128 healthy older adults (ages 40-88 years). Mean total B12 and homocysteine concentrations were not significantly different among the 3 genotypes. Mean holoTCII concentration was significantly higher in those subjects homozygous for the proline form of TCII (PP) compared with those homozygous for the arginine form (RR) and heterozygotes (PR) (P ≤ .006). In addition, mean methylmalonic acid concentrations were significantly lower in the PP and PR groups compared with the RR group (P ≤ .02). The PP genotype may be more efficient in delivering B12 to tissues, resulting in enhanced B12 functional status. TCII genotype may thus influence susceptibility to B12 deficiency.
Functional characterization of recombinant FV Hong Kong and FV Cambridge
Authors: Norstrøm Eva , Thorelli Elisabeth , Dahlbäck Björn 
Published: October 2002

AbstractIn factor V (FV) Cambridge (Arg306Thr) and Hong Kong (Arg306Gly), a cleavage site for anticoagulant activated protein C (APC), which is crucial for the inactivation of FVa, is lost. Although patients carrying FV Hong Kong have a normal APC response, those with FV Cambridge were reported to be APC resistant. To elucidate the molecular characteristics of the 2 FV mutants, we recreated them in a recombinant system and evaluated their functional properties. The 2 FV variants yielded identical APC resistance patterns, with APC responses being intermediate to those of wild-type FV and FV Leiden (Arg506Gln), which is known to be associated with the APC resistance phenotype. In the absence of protein S, APC mediated FVa inactivation curves obtained with the 2 variants were identical, resulting in partial FVa inactivation. In the presence of protein S, both FVa variants were almost completely inactivated because of protein S stimulation of the cleavage at Arg679. In a FVIIIa degradation system, both FV variants demonstrated slightly impaired APC cofactor activity. The ability of APC to cleave at Arg506 and at Arg679 in FVa Cambridge and Hong Kong and the slight decrease in APC cofactor activity of the 2 FV variants may explain the low thrombotic risk associated with these Arg306 mutations. In conclusion, we demonstrate that recombinant FV Cambridge and Hong Kong behave identically in in vitro assays and provide a mechanism for the low thrombotic risk associated with these FV mutations.
Rapamycin inhibits macropinocytosis and mannose receptor–mediated endocytosis by bone marrow–derived dendritic cells
Authors: Hackstein Holger , Taner Timucin , Logar Alison J. , Thomson Angus W. 
Published: October 2002

AbstractDendritic cells (DCs) are professional antigen-presenting cells (APCs) that use 2 major pathways for antigen uptake: constitutive macropinocytosis and mannose receptor–mediated endocytosis. Efficient endocytosis is critical for DCs to fulfill their sentinel function in immunity. We investigated the influence of the immunosuppressive macrolide rapamycin on macropinocytosis of fluorescein isothiocyanate (FITC)–albumin and mannose receptor–mediated endocytosis of FITC-dextran by murine bone marrow–derived DCs by flow cytometry. The data show that (1) at a low, physiologically relevant concentration (1 ng/mL), rapamycin impairs macropinocytosis and mannose receptor–mediated endocytosis; (2) the effects are independent of DC maturation and can be demonstrated specifically in immature CD11c+ major histocompatibility complex (MHC) class IIlo DCs by 3-color flow cytometry; (3) inhibition of endocytosis is not related to apoptotic cell death; and (4) molar excess of the structurally related molecule FK506 inhibits the actions of rapamycin. The inhibitory effects of rapamycin on DC endocytosis were confirmed in vivo. To our knowledge, this is the first report that a clinically relevant immunosuppressant inhibits DC endocytosis.
Stomatin is a major lipid-raft component of platelet α granules
Authors: Mairhofer Mario , Steiner Marianne , Mosgoeller Wilhelm , Prohaska Rainer , Salzer Ulrich 
Published: October 2002

AbstractLipid rafts are detergent-resistant, cholesterol- and sphingolipid-rich membrane domains that are involved in important cellular processes such as signal transduction and intracellular trafficking. Stomatin, a major lipid-raft component of erythrocytes and epithelial cells, is also an abundant platelet protein. Microscopical methods and subcellular fractionation showed that stomatin is located mainly at the α-granular membrane. The lipid-raft marker proteins flotillin-1 and flotillin-2 were also present in platelets but excluded from α granules. Stomatin and the flotillins were associated with Triton X-100–insoluble lipid rafts. Whereas stomatin was partly soluble in Triton X-100, it was insoluble in the detergents Lubrol and 3-[(3-cholamidopropyl)dimethylamonio]-1-propyl sulfonate (CHAPS). Flotation experiments after CHAPS lysis of platelets revealed a distinct set of lipid-raft–associated proteins, which were identified by matrix-assisted laser desorption/ionization mass spectrometry as stomatin, flotillin-1, flotillin-2, CD36, CD9, integrin αIIbβ3, and the glucose transporter GLUT-3. Stomatin, the flotillins, and CD36 were exclusively present in this lipid-raft fraction. Activation of platelets by calcium ionophore A23187 or thrombin led to translocation of stomatin to the plasma membrane, cleavage by calpain, and specific sorting into released microvesicles. In conclusion, this study demonstrated the existence of α-granular lipid rafts and suggests an important role for stomatin in the organization and function of α granules.
CCAAT/enhancer-binding proteins are required for granulopoiesis independent of their induction of the granulocyte colony-stimulating factor receptor
Authors: Wang Qian-fei , Friedman Alan D. 
Published: October 2002

AbstractPotential redundancy among members of the CCAAT/enhancer-binding protein (C/EBP) family in myeloid cells is indicated by the ability of C/EBPβ to replace C/EBPα in vivo, by the expression of granulocyte colony-stimulating factor receptor (G-CSFR) on C/EBPα−/− cell lines, and by our finding that as with C/EBPα–estrogen receptor (C/EBPα-ER), either C/EBPβ-ER or C/EBPδ-ER can induce terminal granulopoiesis in 32D cl3 cells. To assess the consequences of globally inhibiting C/EBPs, we employed KαER, containing a Kruppel-associated box (KRAB) transrepression domain, the C/EBPα DNA-binding domain, and an ER ligand-binding domain. C/EBPs have a common DNA-binding consensus, and activation of KαER repressed transactivation by endogenous C/EBPs 50-fold and reduced endogenous G-CSFR expression. In 32D cl3 cells coexpressing exogenous G-CSFR, activation of KαER prevented and even reversed myeloperoxidase, lysozyme, lactoferrin, and C/EBPε RNA induction by G-CSF. In contrast, induction of PU.1 and CD11b, a gene regulated by PU.1 but not by C/EBPs, was unaffected. A KαER variant incapable of binding DNA owing to an altered leucine zipper did not affect 32D cl3 differentiation. Transduction of KαER into murine hematopoietic progenitor cells suppressed the formation of granulocyte colony-forming units, even in cytokines that enable C/EBPα−/−progenitors to differentiate into neutrophils. The formation of macrophage and of granulocyte-macrophage colony-forming units were also inhibited, but erythroid burst-forming units grew normally. Thus, in 32D cl3 cells and perhaps normal progenitors, C/EBPs are required for granulopoiesis beyond their ability to induce receptors for G-CSF and other cytokines. One requisite activity may be activation of the C/EBPε gene by C/EBPα, as either C/EBPα-ER or C/EBPβ-ER rapidly elevated C/EBPε RNA in 32D cl3 cells in the presence of cycloheximide but not actinomycin D.
Human mast cell progenitors use α4-integrin, VCAM-1, and PSGL-1 E-selectin for adhesive interactions with human vascular endothelium under flow conditions
Authors: Boyce Joshua A. , Mellor Elizabeth A. , Perkins Brandy , Lim Yaw-Chyn , Luscinskas Francis W. 
Published: October 2002

AbstractMast cells (MCs) are central to asthma and other allergic diseases, and for responses to infection and tissue injuries. MCs arise from committed progenitors (PrMCs) that migrate from the circulation to tissues by incompletely characterized mechanisms, and differentiate in situ in perivascular connective tissues of multiple organs. PrMCs derived in vitro from human cord blood were examined for adhesion molecule expression and their ability to adhere to human umbilical vein endothelial cells (HUVECs) under conditions that mimic physiologic shear flow. The PrMCs expressed α4β1, low levels of β7, and the β2-integrins αLβ2 and αMβ2. The PrMCs also expressed PSGL-1, but not L-selectin. At low (0.5 dynes/cm2-1.0 dynes/cm2) shear stress, PrMCs attached and rolled on recombinant E-selectin and P-selectin and VCAM-1. An anti–PSGL-1 monoclonal antibody (mAb) blocked essentially all adhesion to P-selectin but reduced adhesion to E-selectin by only 40%, suggesting PrMCs express other ligands for E-selectin. PrMCs adhered strongly to tumor necrosis factor-α (TNF-α)–activated HUVECs, whereas adhesion to interleukin 4 (IL-4)–activated HUVECs was lower. PrMC adhesion to IL-4–activated HUVECs was totally α4-integrin– and VCAM-1–dependent. Adhesion to TNF-α–activated HUVECs was blocked by 50% by mAbs against α4-integrin, vascular cell adhesion molecule–1 (VCAM-1), E-selectin, or PSGL-1, whereas combinations of mAbs to α4-integrin plus PSGL-1, or VCAM-1 plus E-selectin, blocked adhesion by greater than 70%. Thus, PrMCs derived in vitro predominantly use α4-integrin, VCAM-1, PSGL-1, and other ligands that bind E-selectin for adhesion to cytokine-activated HUVEC monolayers. These observations may explain the abundance of MCs at sites of mucosal inflammation, where VCAM-1 and E-selectin are important inducible receptors.
The coiled-coil domain and Tyr177 of bcr are required to induce a murine chronic myelogenous leukemia–like disease by bcr/abl
Authors: He Yiping , Wertheim Jason A. , Xu Lanwei , Miller Juli P. , Karnell Fredrick G. , Choi John K. , Ren Ruibao , Pear Warren S. 
Published: October 2002

Abstract
The bcr/abl fusion in chronic myelogenous leukemia (CML) creates a chimeric tyrosine kinase with dramatically different properties than intact c-abl. In P210 bcr/abl, the bcr portion includes a coiled-coil oligomerization domain (amino acids 1-63) and a grb2-binding site at tyrosine 177 (Tyr177) that are critical for fibroblast transformation, but give variable results in other cell lines. To investigate the role of the coiled-coil domain and Tyr177 in promoting CML, 4 P210 bcr/abl-derived mutants containing different bcr domains fused to abl were constructed. All 4 mutants, Δ(1-63) bcr/abl, (1-63) bcr/abl, Tyr177Phe bcr/abl, and (1-210) bcr/abl exhibited elevated tyrosine kinase activity and conferred factor-independent growth in cell lines. In contrast, differences in the transforming potential of the 4 mutants occurred in our mouse model, in which all mice receiving P210 bcr/abl-expressing bone marrow cells exclusively develop a myeloproliferative disease (MPD) resembling human CML. Of the 4 mutants assayed, only 1-210 bcr/abl, containing both the coiled-coil domain and Tyr177, induced MPD. Unlike full-length P210, this mutant also caused a simultaneous B-cell acute lymphocytic leukemia (ALL). The other 3 mutants, (1-63) bcr/abl, Tyr177Phe bcr/abl, and Δ(1-63) bcr/abl, failed to induce an MPD but instead caused T-cell ALL. These results show that both the bcr coiled-coil domain and Tyr177 are required for MPD induction by bcr/abl and provide the basis for investigating downstream signaling pathways that lead to CML.
A mouse orthologue of puromycin-insensitive leucyl-specific aminopeptidase is expressed in endothelial cells and plays an important role in angiogenesis
Authors: Miyashita Hiroki , Yamazaki Tohru , Akada Tetsuya , Niizeki Osamu , Ogawa Minetaro , Nishikawa Shin-ichi , Sato Yasufumi 
Published: October 2002

AbstractUsing polymerase chain reaction–coupled subtractive hybridization, we have isolated genes expressed during the in vitro differentiation of murine embryonic stem cells into endothelial cells (ECs). Among the genes obtained, we identified one gene that was inducible by vascular endothelial growth factor (VEGF) in the murine EC line MSS31. Analysis of the nucleotide and deduced amino acid sequences revealed that the protein was composed of 930 amino acids, including an HEXXH(X)18E consensus sequence of the M1 aminopeptidase family, and is thought to be a mouse orthologue of puromycin-insensitive leucyl-specific aminopeptidase (mPILSAP). The recombinant protein hydrolyzed N-terminal leucyl and methionyl residues from synthetic substrates. Immunohistochemical analysis revealed that mPILSAP was expressed in ECs during postnatal angiogenesis. Specific elimination of mPILSAP expression by antisense oligodeoxynucleotide (AS-ODN) attenuated VEGF-stimulated proliferation, migration, and network formation of ECs in vitro. Moreover, AS-ODN to mPILSAP inhibited angiogenesis in vivo. These results suggest a novel function of mPILSAP, which is expressed in ECs and plays an important role in angiogenesis.
Human primary and memory cytotoxic T lymphocyte responses are efficiently induced by means of CD40-activated B cells as antigen-presenting cells: potential for clinical application
Authors: von Bergwelt-Baildon Michael S. , Vonderheide Robert H. , Maecker Britta , Hirano Naoto , Anderson Karen S. , Butler Marcus O. , Xia Zhinan , Zeng Wan Y. , Wucherpfennig Kai W. , Nadler Lee M. , Schultze Joachim L. 
Published: October 2002

AbstractCD40 engagement is the major signal that induces B cells to efficiently present antigen to T cells. We previously demonstrated that human peripheral blood–derived CD40-activated B cells (CD40–B cells) function as antigen-presenting cells (APCs). Here, we have established a culture system to generate these APCs under clinically applicable conditions using guanylic acid–grade soluble trimeric CD40 ligand. To monitor APC function and antigen loading for these cells, simple and efficient quality control assays have been developed. Using this approach, we demonstrate that CD40–B cells from healthy donors and cancer patients are fully functional and equally expanded in long-term cultures. These B cells boost robust memory T-cell responses, but more importantly, they also prime naive T-cell responses against neoantigens ex vivo. CD40–B cells overcome current obstacles, such as the difficulty of isolation, generation, and long-term expansion observed with other APCs. Therefore, they are an excellent source of professional APCs for immune assessment, antigen discovery, and antigen-specific immunotherapy.
Synergistic induction of apoptosis by simultaneous disruption of the Bcl-2 and MEK/MAPK pathways in acute myelogenous leukemia
Authors: Milella Michele , Estrov Zeev , Kornblau Steven M. , Carter Bing Z. , Konopleva Marina , Tari Ana , Schober Wendy D. , Harris David , Leysath Clinton E. , Lopez-Berestein Gabriel , Huang Ziwei , Andreeff Michael 
Published: October 2002

Abstract
Recent studies suggest that the Bcl-2 and mitogen-activated protein kinase (MAPK) pathways together confer an aggressive, apoptosis-resistant phenotype on acute myelogenous leukemia (AML) cells. In this study, we analyzed the effects of simultaneous inhibition of these 2 pathways. In AML cell lines with constitutively activated MAPK, MAPK kinase (MEK) blockade by PD184352 strikingly potentiated the apoptosis induced by the small-molecule Bcl-2 inhibitor HA14-1 or by Bcl-2 antisense oligonucleotides. Isobologram analysis confirmed the synergistic nature of this interaction. Moreover, MEK blockade overcame Bcl-2 overexpression-mediated resistance to the proapoptotic effects of HA14-1. Most importantly, simultaneous exposure to PD184352 significantly (P = .01) potentiated HA14-1–mediated inhibition of clonogenic growth in all primary AML samples tested. These findings show that the Bcl-2 and MAPK pathways are relevant molecular targets in AML and that their concurrent inhibition could be developed into a new therapeutic strategy for this disease.
Reflection and transmission responses of a layered isotropic viscoelastic medium
Authors: Ursin Bjørn , Stovas Alexey 
Published: October 2002

Transmission effects in the overburden are important for amplitude versus offset (AVO) studies and for true‐amplitude imaging of seismic data. Thin layers produce transmission effects which depend on frequency and slowness. We consider an inhomogeneous viscoelastic layered isotropic medium where the parameters depend on depth only. This takes into account both the effects of intrinsic attenuation and the effects of the layering (including changes in attenuation). The seismic wavefield is decomposed into up‐ and downgoing waves scaled with respect to the vertical energy flux. This gives important symmetry relations for the reflection and transmission responses. For a stack of homogeneous layers, the exact reflection response can be computed in a numerically stable way by a simple layer‐recursive algorithm.The reflection and transmission coefficients at a plane interface are functions of the complex medium parameters (depending on frequency) and the real horizontal slowness parameter. Approximations for weak contrast and weak attenuation are derived and compared to the exact values in two numerical examples.We derive first‐order approximations of the PP and SS transmission responses which are direct extensions of the well‐known O'Doherty‐Anstey formula. They consist of a phase shift and attenuation term from direct transmission through the layers and two attenuation terms from backscattered P‐ and S‐waves. The average of these transmission responses may be used for overburden corrections in AVO analysis. The first‐order PP and PS reflection responses have been computed for a stack of very thin layers corresponding to about 2800 m thickness. Because of a lack of data, the intrinsic attenuation was assumed to be constant in the layers. In the seismic frequency band, the intrinsic attenuation dominates the thin‐layer effects. Approximate and exact layer‐recursive modeling of the reflection responses for this layered medium are in good agreement.
A multimodel method for depth estimation from magnetic data
Authors: Thurston Jeffrey B. , Smith Richard S. , Guillon Jean-Claude 
Published: October 2002

The local wavenumber and a multimodel wavenumber are complex attributes derived from a complex analytic signal. These quantities have been used to interpret anomalies arising from contacts, thin sheets, and horizontal cylinders. A new multimodel wavenumber can be used for computing depths of 2-D thick dikes and 2-D sloping steps. These two multimodel wavenumbers have been incorporated into a depth-estimation algorithm based on automatic curve matching. This algorithm works on profile data and has three appealing features: (1) the most appropriate of these five models is selected automatically; (2) the automatic curve matching uses a least-squares technique to reject responses that do not conform to the model assumptions; and (3) interference from distant sources can be accounted for as a base-level shift of the multimodel wavenumber curves. Applying the automatic technique to survey data from the Western Canada sedimentary basin yields four thick dikes between 3400 and 4300 m below sensor. These depths are equivalent to 2.2 and 3.1 km below sea level, which is consistent with the basement depths derived from drillhole information. Using these solutions as a starting point in an iterative forward modeling exercise, the measured data were explained with a geologically reasonable model.
Estimation of gas hydrate and free gas saturation, concentration, and distribution from seismic data
Authors: Lu Shaoming , McMechan George A. 
Published: October 2002

Gas hydrates contain a major untapped source of energy and are of potential economic importance. The theoretical models to estimate gas hydrate saturation from seismic data predict significantly different acoustic/elastic properties of sediments containing gas hydrate; we do not know which to use. Thus, we develop a new approach based on empirical relations. The water‐filled porosity is calibrated (using well‐log data) to acoustic impedance twice: one calibration where gas hydrate is present and the other where free gas is present. The water‐filled porosity is used in a combination of Archie equations (with corresponding parameters for either gas hydrate or free gas) to estimate gas hydrate or free gas saturations.The method is applied to single‐channel seismic data and well logs from Ocean Drilling Program leg 164 from the Blake Ridge area off the east coast of North America. The gas hydrate above the bottom simulating reflector (BSR) is estimated to occupy ∼3–8% of the pore space (∼2–6% by volume). Free gas is interpreted to be present in three main layers beneath the BSR, with average gas saturations of 11–14%, 7–11%, and 1–5% of the pore space (6–8%, 4–6%, and 1–3% by volume), respectively. The estimated saturations of gas hydrate are very similar to those estimated from vertical seismic profile data and generally agree with those from independent, indirect estimates obtained from resistivity and chloride measurements. The estimated free gas saturations agree with measurements from a pressure core sampler. These results suggest that locally derived empirical relations between porosity and acoustic impedance can provide cost‐effective estimates of the saturation, concentration, and distribution of gas hydrate and free gas away from control wells.
Novel Targets for Lung Cancer Therapy: Part II
Authors: Dy Grace K. , Adjei Alex A. 
Published: October 2002

ABSTRACT: Lung cancer is the second most common form of cancer in the United States, and although it accounts for 15% of all cancers, it is the most lethal, accounting for approximately 28% of cancer deaths. In 2002, it is estimated that 177,000 new cases of lung cancer will be diagnosed in the United States, and an estimated 160,000 men and women will die from the disease. This mortality rate is greater than that attributable to colorectal, breast, and prostate cancer combined. Systemic treatments for lung cancer with standard chemotherapy agents are still relatively ineffective. Agents targeting novel proliferative and survival pathways in lung cancer are needed to improve treatment outcomes. In recent years, numerous agents inhibiting aberrant processes in tumor cells have undergone clinical evaluation. This review is the second of a two-part series that summarizes pertinent preclinical and clinical information on novel drugs that target critical abnormalities in lung cancer. In this article, agents that were developed to inhibit various aspects of tumor protein trafficking and protein degradation, cell cycle regulation, angiogenesis, and antigenicity are described. Future approaches to treatment are suggested.