1,720,967 research outputs found
Beretti F., Cermelli C., Cenacchi V., Orsi C., Blasi E., Portolani M.
No full textMicroglia activation occurs during brain injury, ischemia and several neurological disorders. Moreover, microglial cells are highly dynamic structures also during the “resting” state in vivo, releasing neurotrophic factors and/or pro- and anti-inflammatory cytokines. Recently, we obtained a transmissible cytotoxic activity (TCA) from the cerebrospinal fluid of a patient with brain ischemia. We demonstrated that this TCA is associated with one or 2 protein(s), that supposedly underwent misfolding, and causes apoptotic cytotoxicity in a variety of cell lines. In this work, we studied microglia response to this TCA. The murine brain macrophage cell line RR4 was stimulated with TCA. Its response was evaluated as phagocytosis and antifungal activity against C. Albicans, and as secretion pattern, measuring MIP-1and TNF- by commercial sandwich ELISAs, nitric oxide (NO) by Griess reaction and phosphorylation of p38 by Fast Activated Cell-based ELISA.Microglia stimulated with TCA showed an increase in phagocytosis of C. albicans. On the contrary, the macrophage capability to kill the ingested fungi was diminished. The analysis of soluble factors secreted by microglial cells in response to TCA demonstrated an increase in MIP-1TNF- NO and an activation of p38 MAP kinase. These results suggest an initial microglia activation induced by TCA leading to an increase in candida ingestion not followed by killing of the fungus. Activation of p38 MAP kinase could suggest the induction of a signaling cascade leading to TCA production which in turn could cause failure in the antifungal activity. Moreover, MIP-1a, NO and TNF-a secretion by microglia cells and induction of apoptosis could provide an in vitro model for the cell events associated with brain ischemia
HSV-1 induces macrophage activation and dysregulation in monocytes
No full textClinical cases of double infections by fungi and viruses are increasing, especially in immunocompromised hosts. To date, the biomolecular events that characterize the outcome of polymicrobic diseases remain poorly investigated and little is known on the mutual interactions occurring between pathogens. In order to investigate the interplay between microrganisms co-infecting macrophagic cells, we recently set up an in vitro model in which a monocytic cell line was infected with human herpesvirus 6 and C. neoformans. In the present work, we used an similar model to understand the molecular mechanisms underlying interactions between herpes simplex virus 1 (HSV-1) and C. albicans. The monocytic cell line THP-1 was infected with HSV-1 and, after an overnight incubation, cells were exposed to C. albicans. The cell response to the viral infection was evaluated as phagocytosis of C. albicans and killing of the ingested fungus. Moreover, a number of activation markers (CD38, CD69, CD95) and adhesion molecules (CD54, TLR-2, CD11b, CD106) was evaluated by FACS analysis in THP-1 cells. THP-1 cells infected with HSV-1 showed increased phagocytosis of C. albicans but reduced killing capability, suggesting that in the course of a double infection macrophages could contribute to yeast dissemination. Activation markers (CD38 and CD69) were found down expressed by FACS analysis in HSV-1-infected THP-1 cells, accounting for the failure in the antifungal activity
Human herpesvirus-6 dysregulates monocyte-mediated anti cryptococcal defences
No full textIn order to investigate the interplay occurring between pathogens in the course of double infections, an in vitro model was set up in which the monocytic cell line THP-1 was exposed to Cryptococcus neoformans (Cn) and human herpesvirus 6 (HHV-6). Cn and HHV-6, both highly neurotropic, can cause serious diseases of the central nervous system and have monocytes, among other cell types, as target cells, causing alteration of their secretion pattern. Here, it was shown that unlike THP-1 cells exposed to cell-free virus inocula, THP-1 exposed to HHV-6-producing lymphocytes exhibited augmented phagocytosis against Cn. The phenomenon occurred after 24 h of monocyte/lymphocyte co-culture and was independent of direct cell-to-cell contact. Moreover, in the presence of HHV-6, THP-1 cells expressed enhanced secretory responses but reduced capability to counteract fungal infection: the enhanced ingestion by monocytes was followed by facilitated fungal survival and replication. These data provide initial in vitro evidence that HHV-6 may dysregulate monocyte-mediated anticryptococcal defences with an overall pro-cryptococcus result
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
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
Antiviral activity of propolis
No full textPropolis, a natural product of beehives, comprises a complex of chemicals, the most important being flavonoids, which are known to havw antiviral activities. Alcohol solutions of 5 different commercial products were tested in vitro against HSV-1, CoxB5, Adenovirus, Mumps virus.All the propolis preparations under study showed antiviral activity against at least some of the virus tested, although with different efficacy
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