871 resultados para presentation
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"Designed for use with three companion books: Fair thought and speech, Corporate correspondence, and Letter writing in action."
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Includes bibliographies
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Mode of access: Internet.
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Natural killer T (NKT) cells play an important role in controlling cancers, infectious diseases and autoimmune diseases. Although the rhesus macaque is a useful primate model for many human diseases such as infectious and autoimmune diseases, little is known about their NKT cells. We analyzed Valpha24TCR+ T cells from rhesus macaque peripheral blood mononuclear cells stimulated with aalpha-galactosylceramide (a-GalCer) and interleukin-2. We found that rhesus macaques possess Va24TCR+ T cells, suggesting that recognition of alpha-GalCer is highly conserved between rhesus macaques and humans. The amino acid sequences of the V-J junction for the Valpha24TCR of rhesus macaque and human NKT cells are highly conserved (93% similarity), and the CD1d alpha1-alpha2 domains of both species are highly homologous (95.6%). These findings indicate that the rhesus macaque is a useful primate model for understanding the contribution of NKT cells to the control of human diseases.
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Epstein-Barr virus (EBV)-encoded nuclear antigen (EBNA)1 is thought to escape cytotoxic T lymphocyte (CTL) recognition through either self-inhibition of synthesis or by blockade of proteasomal degradation by the glycine-alanine repeat (GAr) domain. Here we show that EBNA1 has a remarkably varied cell type-dependent stability. However, these different degradation rates do not correspond to the level of major histocompatibility complex class I-restricted presentation of EBNA1 epitopes. In spite of the highly stable expression of EBNA1 in B cells, CTL epitopes derived from this protein are efficiently processed and presented to CD8(+) T cells. Furthermore, we show that EBV-infected B cells can readily activate EBNA1-specific memory T cell responses from healthy virus carriers. Functional assays revealed that processing of these EBNA1 epitopes is proteasome and transporter associated with antigen processing dependent. We also show that the endogenous presentation of these epitopes is dependent on the newly synthesized protein rather than the long-lived stable EBNA1. Based on these observations, we propose that defective ribosomal products, not the full-length antigen, are the primary source of endogenously processed CD8(+) T cell epitopes front EBNA1.
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Background: Although immunization with tumor antigens can eliminate many transplantable tumors in animal models, immune effector mechanisms associated with successful immunotherapy of epithelial cancers remain undefined. Methods: Skin from transgenic mice expressing the cervical cancer-associated tumor antigen human papillornavirus type 16 (HPV16) E6 or E7 proteins from a keratin 14 promoter was grafted onto syngeneic, non-transgenic mice. Skin graft rejection was measured after active immunization with HPV16 E7 and adoptive transfer of antigen-specific T cells. Cytokine secretion of lymphocytes from mice receiving skin grafts and immunotherapy was detected by enzyme-linked immunosorbent assay, and HPV16 E7-specific memory CD8(+) T cells were detected by flow cytometry and ELISPOT. Results: Skin grafts containing HPV16 E6- or E7-expressing keratinocytes were not rejected spontaneously or following immunization with E7 protein and adjuvant. Adoptive transfer of E7-specific T-cell receptor transgenic CD8(+) T cells combined with immunization resulted in induction of antigen-specific interferon gamma-secreting CD8(+) T cells and rejection of HPV16 E7-expressing grafts. Specific memory CD8(+) T cells were generated by immunotherapy. However, a further HPV16 E7 graft was rejected from animals with memory T cells only after a second E7 immunization. Conclusions: Antigen-specific CD8(+) T cells can destroy epithelium expressing HPV16 E7 tumor antigen, but presentation of E7 antigen from skin is insufficient to reactivate memory CD8(+) T cells induced by immunotherapy. Thus, effective cancer immunotherapy in humans may need to invoke sufficient effector as well as memory T cells.
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The H I Parkes All-Sky Survey (HIPASS) catalogue forms the largest uniform catalogue of H I sources compiled to date, with 4315 sources identified purely by their H I content. The catalogue data comprise the southern region delta < + 2&DEG; of HIPASS, the first blind H I survey to cover the entire southern sky. The rms noise for this survey is 13 mJy beam(-1) and the velocity range is -1280 to 12 700 km s(-1). Data search, verification and parametrization methods are discussed along with a description of measured quantities. Full catalogue data are made available to the astronomical community including positions, velocities, velocity widths, integrated fluxes and peak flux densities. Also available are on-sky moment maps, position-velocity moment maps and spectra of catalogue sources. A number of local large-scale features are observed in the space distribution of sources, including the super-Galactic plane and the Local Void. Notably, large-scale structure is seen at low Galactic latitudes, a region normally obscured at optical wavelengths.
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Infection of humans with the West Nile flavivirus principally occurs via tick and mosquito bites. Here, we document the expression of antigen processing and presentation molecules in West Nile virus (WNV)-infected human skin fibroblast (HFF) cells. Using a new Flavivirus-specific antibody, 4G4, we have analyzed cell surface human leukocyte antigen (HLA) expression on virus-infected cells at a single cell level. Using this approach, we show that West Nile Virus infection alters surface HLA expression on both infected HFF and neighboring uninfected HFF cells. Interestingly, increased surface HLA evident on infected HFF cultures is almost entirely due to virus-induced interferon (IFN)alpha/beta because IFNalpha/beta-neutralizing antibodies completely prevent increased surface HLA expression. In contrast, RT-PCR analysis indicates that WNV infection results in increased mRNAs for HLA-A, -B, and -C genes, and HLA-associated molecules low molecular weight polypeptide-2 (LMP-2) and transporter associated with antigen presentation-1 (TAP-1), but induction of these mRNAs is not diminished in HFF cells cultured with IFNalpha/beta-neutralizing antibodies. Taken together, these data support the idea that that both cytokine-dependent and cytokine-independent mechanisms account for WNV-induced HLA expression in human skin fibroblasts. (C) 2004 Elsevier Inc. All rights reserved.
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A Viet Namese child presented with a history of abdominal pain. Shortly afterwards, he vomited eight live trematode flukes that were collected and morphologically identified as Fasciolopsis buski. The identification was confirmed by DNA analysis. Adult worms of F buski from humans are very rarely seen except at autopsy, and this is the first such report from Viet Nam. (C) 2003 Royal Society of Tropical Medicine and Hygiene. Published by Elsevier Ltd. All rights reserved.
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In subtropical and tropical climates, dehydration is common in cystic fibrosis patients with respiratory exacerbations. This may lead to a clinical presentation of metabolic alkalosis with associated hyponatraemia and hypochloraemia. An adult cystic fibrosis patient who presented with a severe respiratory exacerbation accompanied by metabolic alkalosis is presented and the effects of volume correction are reported.
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Burning mouth syndrome is an oral dysaesthesia presenting as a burning sensation of the tongue and less frequently other oral and peri-oral sites. There may be other coincident symptoms and signs, but the defining feature is the absence of any obvious organic cause. Because of this the condition frequently remains unrecognized for extended periods with a variable progression of symptoms. The current paper describes the complex presentation of burning mouth syndrome with the major aim of increasing recognition.
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The mechanisms responsible for the immunosuppression associated with sepsis or some chronic blood infections remain poorly understood. Here we show that infection with a malaria parasite (Plasmodium berghei) or simple systemic exposure to bacterial or viral Toll-like receptor ligands inhibited cross-priming. Reduced cross-priming was a consequence of downregulation of cross-presentation by activated dendritic cells due to systemic activation that did not otherwise globally inhibit T cell proliferation. Although activated dendritic cells retained their capacity to present viral antigens via the endogenous major histocompatibility complex class I processing pathway, antiviral responses were greatly impaired in mice exposed to Toll-like receptor ligands. This is consistent with a key function for cross-presentation in antiviral immunity and helps explain the immunosuppressive effects of systemic infection. Moreover, inhibition of cross-presentation was overcome by injection of dendritic cells bearing antigen, which provides a new strategy for generating immunity during immunosuppressive blood infections.
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Acute epiploic appendagitis is an uncommon cause of abdominal pain. It is caused by torsion of an epiploic appendage or spontaneous venous thrombosis of a draining appendageal vein.1 The diagnosis of this condition primarily relies on cross-sectional imaging and is made most often after computed tomography (CT). Clinically, it is most often mistaken for acute diverticulitis. Approximately 7.1% of patients investigated to exclude sigmoid diverticulitis have imaging findings of primary epiploic appendagitis.