14,107 research outputs found

    Role of the Cd40-cd40 Ligand Interaction in Cd4(+) T Cell Activation of Monocyte Interleukin-1 Synthesis

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    Most studies of the induction of cytokine synthesis in monocytes have used an exogenous triggering agent such as Lipolpoysaccharide (LPS). However, during nonseptic chronic inflammatory responses (e.g., rheumatoid arthritis) monocyte activation occurs as a result of T cell generated signals. This report demonstrated that plasma membranes from anti-CD3 activated peripheral CD4\sp{+} T cells (Tm\sp{\rm A}) but not from resting CD4\sp{+} cells (Tm\sp{\rm R}) induced monocytes to synthesize IL-1 in the absence of costimulatory cytokines. The expression kinetics of the molecule(s) unique to activated T cells which interact with monocyte receptors to induce IL-1 demonstrated that optimal expression occurred at 6h post activation. This matched Lederman\u27s, et al., (1992) previously reported kinetics of expression of CD40 ligand (CD40L) on activated peripheral T cells, implicating the CD40-CD40L interaction as a candidate for the initiator of IL-1 induction in monocytes. In this work, it was demonstrated that the signal could be reduced up to 85% by addition of 5c8, a monoclonal anti-CD40L antibody. In addition, a monoclonal anti-CD40 IgM (BL-C4) induced resting monocytes to synthesize IL-1. Experiments demonstrated that crosslinking the CD40 molecules on monocytes was critical for IL-1 induction. Tm\sp{\rm A} but not Tm\sp{\rm R} also up-regulated cell surface expression of adhesion/costimulatory molecules on monocytes including CD40, ICAM-1, and LFA-3. Anti-CD40 signaling up-regulated expression of ICAM-1 and LFA-3. Experiments suggested that signaling through CD40 may utilize a protein tyrosine kinase (PTK) mediated pathway but not a protein kinase C mediated pathway and studies using THP-1, a premonocytic cell line, indicated that the transcription factor, NF-κ\kappaB, was activated through anti-CD40 signaling. Since CD40 ligand-transfected cells alone did not induce IL-1 but Tm\sp{\rm A} did, it was considered that an additional costimulatory cell surface molecule was required. Preliminary experiments suggested that CD69 may be required. In summary, these results indicate that contact-dependent T cell-monocyte interactions, alone, can activate inflammatory cytokine production by resting monocytes and that a critical component of this interaction is the CD40-CD40L signaling event

    M meson and a generalization of the Pomeranchuk relations

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    Under the hypothesis that a K-π resonance is vector, we examine its role in the associated production of Λ by π and in Λ production by K. We shall demonstrate the existence of a new symmetry between two reaction amplitudes. This symmetry may be regarded as a generalization of Pomeranchuk's relations and should appear at high energies and low momentum transfers when both amplitudes are dominated by the same pole or pseudopole, as is to be expected according to the Regge pole hypothesis. Specifically, we find, in considering the details of the role of a strange vector meson in the processes π+N→Λ+K and K +N→Λ+π, that the associated production amplitude in the forward direction (for the K) at high energies is asymptotically equal to the negative of the amplitude characterizing Λ production by a K. The contribution of the dominant pole terms in these amplitudes is constructed for the high-energy limit and the energy and momentum transfer dependences are compared for the alternative hypothesis of composite or elementary particle behavior of a pole term. We discuss experiments which are needed to supply data for a test of the Regge pole hypothesis. The results of these experiments, which are feasible with the new large accelerators, will be most important as guides for the construction of theories of the strong interactions

    A Note on the Leptonic Decays of the K-Meson

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    In this note we present an analysis of the leptonic decay modes of the K-meson in terms of a four-parameter representation of the two form factors F1(q^2) and F3(q^2) which describe the matrix element of the vector current of the weak interactions, . Such a representation, while general enough to take account of the violation of the ΔΙ = 1/2 rule and the possible existence of two resonances in the K-π system, no longer permits unique predictions for the ratio of the electron to muon decay rate, or of the pion spectrum. We therefore suggest that experiments be carried out to determine the four unknown parameters, and theoretical attention be turned to relating these parameters to measurable quantities occurring in related processes

    Chapter 2 - Laboratory Techniques

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    Explore the contents of Bryophyte Ecology, Volume 3, Chapter 2 - Laboratory Techniques by clicking the links above. For the Contents section of this ebook, as well as Volumes 2 through 5, please visit the Bryophyte Ecology Main Page. Use CTRL+F to easily search within PDF files. Ebook sponsored by Michigan Technological University and the International Association of Bryologists.https://digitalcommons.mtu.edu/bryophyte-ecology3/1001/thumbnail.jp

    Binding-incompetent adenovirus facilitates molecular conjugate-mediated gene transfer by the receptor-mediated endocytosis pathway

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    Molecular conjugate vectors may be constructed that accomplish high efficiency gene transfer by the receptor-mediated endocytosis pathway. In order to mediate escape from lysosomal degradation, we have incorporated adenoviruses into the functional design of the conjugate. In doing so, however, we have introduced an additional ligand, which can bind to receptors on the cell surface, undermining the potential for cell specific targeting. To overcome this, we have treated the adenovirus with a monoclonal anti-fiber antibody, which renders the virus incapable of binding to its receptor. The result is a multi-functional molecular conjugate vector, which has preserved its binding specificity while at the same time being capable of preventing lysosomal degradation of endosome-internalized conjugate-DNA complexes. This finding indicates that adenoviral binding is not a prerequisite for adenoviral-mediated endosome disruption

    Relativistic dissipative spin hydrodynamics from kinetic theory with a nonlocal collision term

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    We derive relativistic dissipative spin hydrodynamics from kinetic theory featuring a nonlocal collision term using the method of moments. In this framework, the components of the spin tensor are dynamical variables which obey relaxation-type equations. We find that the corresponding relaxation times are determined by the local part of the collision term, while the nonlocal part contributes to the Navier-Stokes terms in these equations of motion. The spin relaxation time scales are comparable to those of the usual dissipative currents. Finally, the Navier-Stokes limit of the Pauli-Lubanski vector receives contributions proportional to the shear tensor of the fluid, which implies that the polarization of hadrons observed in heavy-ion collisions is influenced by dissipative effects.Comment: 7 pages, 1 figur

    Rare, Threatened and Endangered Vascular Plants in Oregon: An Interim Report

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    This report on rare, threatened and endangered vascular plants in Oregon is a basic document in the process of inventorying the state\u27s natural areas * Prerequisite to the orderly establishment of natural preserves for research and conservation in Oregon are (1) a classification of the ecological types, and (2) a listing of the special organisms, which should be represented in a comprehensive system of designated natural areas. The necessary ecological classification was published in the U.S. Forest Service Pacific Northwest Forest and Range Experiment Station document, Research Natural Area Needs in the Pacific Northwest, by Dyrness et al. (1975). This valuable reference also provided lists of vascular plants of special interest in each major physiographic province, based on early work by Chambers and Siddall. Under the direction of the Oregon Rare and Endangered Plant Species Taskforce, work has actively continued to expand and perfect the list of vascular plant species, to serve the needs of land management and natural area planning in Oregon, and of many other governmental and private activities. Studies of rare and endangered plants in Oregon have involved a unique coalition of professional and amateur botanists, who have systematically gathered data on the distribution, abundance, habitat, and ecological requirements of some 700 native species. Coordination and leadership have come from the Oregon Rare and Endangered Plant Species Taskforce, and specifically from the Taskforce chairman, Jean L. Siddall. The Natural Area Preserves Advisory Committee has long recognized the significance of this effort and has encouraged the Taskforce\u27s goal of assembling a list of rare, threatened and endangered plant species for the State of Oregon. In August,1979, it was decided to support the publication of an interim report, summarizing the present status of all the plants under review by the Taskforce. This list will serve as a working document for the many individuals and organizations, both public and private, needing information on the rare plants in Oregon. This list will be particularly useful to the Natural Heritage Advisory Council (replacing the Natural Area Preserves Advisory Committee) as it develops the Natural Heritage Plan required by Oregon statute. Ultimately, a detailed Oregon List of Rare, Threatened and Endangered Plants will be produced. This current interim report is a timely step toward this goal

    An Accounting Program Merit Pay Survey

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    Basing the compensation of accounting professors on merit pay in order to encourage better teaching, research and service is controversial. Before the effectiveness of merit-based salary plans can be examined empirically, it must be determined which accounting programs use such a system. In this study, the 852 accounting programs in the United States were surveyed to identify the methods in use to adjust the salaries of individual professors. Initial findings indicate that schools using a merit system usually do not also offer time in grade increases and that doctoral granting schools and AACSB accredited schools are more likely to use a merit system. &nbsp
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