1,721,006 research outputs found
Immunomodulatory mechanisms during Echinococcus granulosus infection
No full textThe pathologic events that ensue after humans ingest the eggs of Echinococcus granulosus and continue while cystic echinococcosis develops, provide an excellent example illustrating the evasive strategies helminth parasites use to develop, progress and cause chronic disease. The hydatid cyst secretes and exposes numerous immunomodulatory molecules to the host's immune system. By characterizing these molecules we can understand the mechanisms that E. granulosus uses for increasing the efficiency and persistency of infection in the host. These molecules modulate both the innate and adaptive arms of the immune response and appear to target cellular and humoral responses. In this review, we discuss recent advances in the immunobiology of host-E. granulosus interactions that provide intriguing insights into the complex interplay between host and parasite that ultimately facilitates parasite survival. © 2008 Elsevier Inc. All rights reserved
Oxidized haemoglobin-driven endothelial dysfunction and immune cell activation: novel therapeutic targets for atherosclerosis.
No full textAtherosclerosis is a chronic inflammatory disease of the arterial wall characterized by endothelial dysfunction, and in which innate and adaptive immune responses have a crucial role. Autoimmune reactions against several self molecules and modified self molecules have been identified in patients with atherosclerotic disease. Oxidative stress, increasingly reported in these patients is the major event causing protein structural modifications, thus inducing the appearance of neo/cryptic epitopes. Following intraplaque haemorrhage large amounts of cell-free haemoglobin (Hb) accumulate within atheroma, due to its impaired clearance by the haptoglobin-CD163 scavenging system. The pro-oxidative intraplaque microenvironment may induce Hb structural changes, thus generating neo/cryptic autoantigenic epitopes and rendering the oxidized self molecule as a dangerous signal for both immune and endothelial cells. In this review, we will present the most relevant information on Hb as a candidate self antigen involved in the pathogenesis of atherosclerotic disease and on its ability to trigger signals that drive endothelial dysfunction and immune cell activation. On these grounds, we will also discuss how these new paradigms may lead to novel therapeutic targets for cardiovascular diseases
T Lymphocyte Autoreactivity in Inflammatory Mechanisms Regulating Atherosclerosis
Full text linkAtherosclerosis has been clearly demonstrated to be a chronic inflammatory disease of the arterial wall. Both cells of the innate and the acquired immune system, particularly monocytes and T lymphocytes, are implicated in the atherogenic process, producing different cytokines with pro- and anti-inflammatory effects. The majority of pathogenic T cells involved in atherosclerosis are of the Th1 profile, that has been correlated positively with coronary artery disease. Many studies conducted to evaluate the molecular factors responsible for the activation of T cells have demonstrated that the main antigenic targets in atherosclerosis are modified endogenous structures. These self-molecules activate autoimmune reactions mainly characterized by the production of Th1 cytokines, thus sustaining the inflammatory mechanisms involved in endothelial dysfunction and plaque development. In this paper we will summarize the different T-cell subsets involved in atherosclerosis and the best characterized autoantigens involved in cardiovascular inflammation
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Thioredoxin peroxidase from Echinococcus granulosus: a candidate to extend the antigenic panel for the immunodiagnosis of human cystic echinococcosis
No full textThe currently available tests for the diagnosis of cystic echinococcosis (CE), enzyme-linked immunosorbent assay (ELISA), and immunoblotting (113) lack sensitivity and specificity, and antigen panels need standardizing. By screening an Echinococcus granulosus cDNA library with IgG1 from patients with CE, we identified E. granulosus thioredoxin peroxidase (EgTPx). Although IB and ELISA achieved the same specificity (92%), ELISA showed higher sensitivity than IB (83% versus 42%) in determining total immunoglobulin G (IgG) specific to EgTPx in CE sera. The percentage of total IgG- and IgG1-positive sera in ELISA was. equally distributed in patients with active, transitional, and inactive disease. Conversely, the percentages of IgG4-positive sera were significantly higher in sera from patients with active than inactive disease (P=0.03). Our data suggest that adding this highly specific recombinant antigen to the standard diagnostic panel of antigens used in ELISA would increase diagnostic sensitivity. Antibodies specific to EgTPx are of potential interest in the host-parasite relationship. (c) 2008 Elsevier Inc. All rights reserved
7-Oxo-cholesterol potentiates pro-inflammatory signaling in human M1 and M2 macrophages
No full textMacrophages, the major cellular components of atherosclerotic plaques, consist of two main subsets: the pro-inflammatory, M1 or classically activated macrophages, and the anti-inflammatory, M2 or alternatively activated macrophages. The molecular and cellular mechanisms that orchestrate the macrophage polarization and activation that may play a role in plaque progression and stability are poorly understood. Recent studies suggest that oxysterols, oxidative stress-mediated cholesterol oxidation products that are abundant in atherosclerotic lesions, may affect macrophage biology. We investigated whether 7-oxo-cholesterol (7oxo-C) affected polarized human M1 and M2 macrophage phenotypes and functions. Monocyte-derived M1 and M2 macrophages were challenged with 7oxo-C and their phenotype analyzed using flow cytometric analysis, and their function via secretome profiling, the presence of endocytosis and matrix metalloproteinase-9 (MMP-9) release. 7oxo-C increased the expression of HLA-DR in M1 macrophages, and CD14 on M2 macrophages. The oxysterol also reduced CD16 expression on M1 macrophages, while reducing their endocytotic capability and increasing MMP-9 secretion in M2 macrophages. Secretome profiling from cultured cell supernatants showed that 7oxo-C stimulated the production of key pro-atherogenic mediators involved in pro-inflammatory, pro-invasive and pro-angiogenic mechanisms both in M1 and M2 cells. Hypoxic conditions potentiated the effects of 7oxo-C on M1 and M2 cells. The ability of 7oxo-C to polarize macrophages toward a pro-inflammatory state represents a potentially novel mechanism by which oxidative stress can contribute to atherosclerotic lesion progression. (C) 2013 Elsevier Inc. All rights reserved
Plaque-infiltrating T lymphocytes in patients with carotid atherosclerosis: an insight into the cellular mechanisms associated to plaque destabilization
No full textAim. Inflammation plays a crucial role in the progression of atherosclerotic plaques. The aim of the present study was to investigate phenotypic and functional characteristics of plaque-infiltrating T lymphocytes associated with a complicated phenotype of carotid atherosclerotic lesions. Methods. Atherosclerotic plaques were obtained from 17 patients undergoing carotid endarterectomy and cultured to isolate infiltrating T lymphocytes. Blood samples were obtained from patients and from 20 sex- and age-matched healthy subjects. The presence of lymphocytes (CD3+ cells) within atherosclerotic plaques was determined by immunohistochemistry. Phenotypic characteristics and intracellular cytokine expression of plaque-infiltrating and circulating T lymphocytes were determined by flow cytometry. Cytokine levels in supernatants from infiltrating T cell cultures were evaluated by enzyme-linked immunosorbent assay. Results. A higher number of CD3+ cells was detected. in complicated than in uncomplicated plaques. Complicated plaques had higher percentages of tumor necrosis factor (TNF)-alpha- and interferon (IFN)-gamma- positive cells than uncomplicated ones, especially in CD4+ subpopulation. In patients the percentages of TNF-alpha-positive cells were higher in infiltrating than in circulating lymphocyte samples. Intracellular TNF-alpha, IFN-gamma, interleukin (IL)-4 and IL-10 expression resulted higher in circulating lymphocyte samples from patients than in those from healthy subjects. Supernatants of infiltrating T cell cultures from complicated plaques showed higher levels of TNF-alpha and lower levels of IL-4 than those from uncomplicated plaques. Conclusion. Our data provide new information on the presence of increased percentages of pro-inflammatory T lymphocytes in complicated plaques with respect to uncomplicated ones and support the concept of the key role played by activated T cells in the progression of atherosclerotic lesions
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