1,720,985 research outputs found
Anticryptococcal Resistance in the Mouse Brain: Beneficial Effects ofLocal Administration of Heat-Inactivated Yeast Cells
No full textUsing a murine model, we have previously shown that brain resistance to local infection with opportunistic fungi is affected by manipulation of the host myelomonocytic compartment. Here, we demonstrate thatintracerebral administration of heat-inactivated Cryptococcus neoformans (H-CN) yeast cells results in a consistent enhancement of mouse survival to subsequent local challenge with lethal doses of C. neoformans. The phenomenon, more pronounced upon double H-CN treatment, is associated with (i) massive local inflammatoryresponse, (ii) reduced growth of the fungus within the brain, and (iii) induction of delayed-type hypersensitivity. Moreover, H-CN treatment confers protection against local heterologous challenges. Our data provide initial evidence that intracerebral administration of H-CN results in the establishment of aspecific and specific immune responses; the mechanisms of elicitation and relative contributions to host antimicrobial resistance remain to be elucidated.Using a murine model, we have previously shown that brain resistance to local infection with opportunistic fungi is affected by manipulation of the host myelomonocytic compartment. Here, we demonstrate that intracerebral administration of heat-inactivated Cryptococcus neoformans (H-CN) yeast cells results in a consistent enhancement of mouse survival to subsequent local challenge with lethal doses of C. neoformans. The phenomenon, more pronounced upon double H-CN treatment, is associated with (i) massive local inflammatory response, (ii) reduced growth of the fungus within the brain, and (iii) induction of delayed-type hypersensitivity. Moreover, H-CN treatment confers protection against local heterologous challenges. Our data provide initial evidence that intracerebral administration of H-CN results in the establishment of a specific and specific immune responses; the mechanisms of elicitation and relative contributions to host antimicrobial resistance remain to be elucidated
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
Indinavir-treated Cryptococcus neoformans promotes an efficient antifungal immune response in immunosuppressed hosts
No full textA previous paper demonstrated that indinavir affects the virulence of Cryptococcus neoformans, thereby rendering the fungus more susceptible to killing by natural effector cells. This study demonstrates that inoculation of immunosuppressed mice with C. neoformans previously exposed to indinavir, in comparison to untreated C. neoformans, results in: (i) a more pronounced secretion of interleukin-12 by splenic dendritic cells; (ii) reduction of CD14 and Fc gammaRs expression on splenic dendritic cells, and upregulation of CD86 and CD40 molecules; (iii) enhancement of interferon-y and interleukin-2 production by splenic T cells and increase of their proliferation in response to fungal antigens; and (iv) survival from an otherwise lethal challenge, correlated with a drastic decrease in colony forming units from brain and liver. In conclusion, these data indicate that indinavir interaction with C. neoformans could be beneficial because of its direct influence on fungal virulence and blunting of the deleterious effects exerted by C. neoformans on host immune response. Thus, indinavir could be crucial in addressing the outcome of cryptococcosis in immunocompromised hosts
Biomolecular events involved in the establishment of brain anticandidal resistance
No full textUsing a murine model, we have demonstrated the establishment of cerebral resistance to local lethal challenge with Candida albicans strain CA-6, by previous intracerebral (i.c.) infection with the low-virulent strain PCA-2. Here we show that i.c. infection with PCA-2 is effective in drastically reducing brain colonization following secondary infection with CA-6. As assessed by colony forming unit assay and histopathological analysis, microbial counts are impaired, granuloma formation and hyphal growth are also reduced in brains of PCA-2- and CA-B-infected mice with respect to CA-6-challenged mice. Furthermore, using PCR studies, we found that, while PCA-2 (i.e. healing infection) induces transient cytokine gene expression in the mouse brain, CA-6 lethal challenge results in long-lasting (until mouse death) high levels of all cytokine gene transcripts assessed. Finally, brains from mice that will resist CA-6 challenge, because of previous infection with PCA-2, also exhibit a transient induction of all cytokine genes. Only IL-1 beta remains highly expressed at all time-points tested. Overall, these results provide evidence that healing and non-healing C. albicans i.c. infections differ in the immune reaction(s) locally evoked, at least in terms of cytokine gene expression, strongly suggesting cytokine involvement in the establishment of brain anticandidal resistance
Intracerebral transfer of an in vitro established microglial cell line: local induction of a protective state against lethal challenge with Candida albicans.
No full textAn in vitro generated BV-2 microglial cell line has been transferred intracerebrally into syngeneic immunocompetent mice prior to local challenge with Candida albicans. The transfer resulted in the establishment of local protection against a lethal dose of C. albicans, which was accompanied by an impairment of yeast growth in the brain and kidneys. Upon histological examination of brain sections from BV-2 cell-pretreated mice, it was found that the size and number of granulomas was reduced as compared to untreated controls receiving Candida alone. These observations provide direct evidence that microglia play a crucial role in the local defense against intracerebral infections
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