907 resultados para inflammatory pseudotumor
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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Phagocytic cells play an important role in nonspecific resistance to fungal infection by mediating an inflammatory response and by a direct fungicidal action. In this study, the functional activity of peritoneal macrophages obtained from hamsters experimentally infected with strain Pb18 of Paracoccidioides brasiliensis was evaluated during 16 weeks of infection. The results showed that macrophages had a higher spreading ability associated with increased production of tumor necrosis factor alpha (TNF-alpha) and enhanced fungicidal activity during the early periods of infection. TNF-alpha levels remained elevated during all periods studied, while low levels of interleukin-1 beta (IL-1 beta) were produced during the infection. A necrotic area with dead fungi was observed at the inoculation site and the infection disseminated only to liver and lymph nodes in a few animals. These results suggest that during the early stages of infection with P. brasiliensis, macrophage activation by the high levels of TNF-alpha limited fungal dissemination. In contrast, in the later stages of infection, high levels of TNF-alpha were observed while the fungicidal activity of macrophages was lower and the animals presented loss of vitality resulting in their death. These observations suggest a complex role of TNF-alpha in experimental paracoccidioidomycosis of Syrian hamsters, involving not only resistance but also pathogenesis.
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Monocytes and macrophages can produce a large repertoire of cytokines and participate in the pathogenesis of granulomatous diseases. We investigated the production of pro- and anti-inflammatory cytokines by monocytes from patients with active paracoccidioidomycosis. Peripheral blood monocytes from 37 patients and 29 healthy controls were cultivated with or without 10 mug/ml of lipopolysaccharide (LPS) for 18 h at 37 degreesC, and the cytokine levels were determined in the culture supernatants by enzyme immunoassay. The results showed that the endogenous levels of tumor necrosis factor alpha (TNF-alpha), interleukin-1 beta (IL-1beta), IL-6, IL-8, IL-10 and transforming growth factor beta detected in the supernatant of patient monocytes cultivated without stimulus were significantly higher than those produced by healthy controls. These data demonstrated that monocytes from patients with active paracoccidioidomycosis produce high levels of cytokines with both inflammatory and anti-inflammatory activities. However, patient monocytes produced significantly lower TNF-alpha and IL-6 levels in response to LPS when compared to normal subjects, suggesting an impairment in their capacity to produce these cytokines after LPS stimulation. Concentrations of IL-1beta, IL-8 and IL-10 in cultures stimulated with LPS were higher in patients than in controls. These results suggest that an imbalance in the production of pro- and anti-inflammatory cytokines might be associated with the pathogenesis of paracoccidioidomycosis. (C) 2003 Editions scientifiques et medicales Elsevier SAS. All rights reserved.
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Leukotrienes are classic inflammatory response mediators considered chemotactic agents and microbicidal activity regulators in cells of the innate immune system, playing a protective role against different infectious agents. In this study, we investigated the involvement of leukotrienes in the course of murine paracoccidioidomycosis based on the following immunologic parameters: cell influx, mieloperoxydase activity, NO production, cytokine production, and fungal recovery in lungs of mice selected according to the intensity of their low (AIRmin) and high (AIRmax) acute inflammatory response. Infection by P. brasiliensis induced considerable production of IL-6, IL-10, IFN-gamma and TNF-alpha cytokines, and led to cell recruitment, as well as NO production in lungs at different study periods. In animals treated with MK886, a leukotriene biosynthesis inhibitor, IFN-gamma, IL-6 and TNF-alpha production was lower, while neutrophil influx and NO production decreased. These results may explain the higher fungal load in lungs of animals in which leukotriene synthesis was inhibited, suggesting that leukotrienes have a possible protective role in experimental paracoccidioidomycosis. AIRmax animals had lower fungal load in comparison with AIRmin ones, which can be related to the AIR phenotype regarding neutrophil migration, besides lower production of NO and pro-inflammatory cytokines. Thus, mice presenting AIRmax background are more resistant to infection by P. brasiliensis.
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Paracoccidioidomycosis is a systemic human mycosis caused by Paracoccidioides brasiliensis (P. brasiliensis), an imperfect dimorphic fungus whose conidia are its infective form. Mice genetically selected for maximum (AIRmax) and minimum (AIRmin) acute inflammatory response were used as experimental paracoccidioidomycosis models. The animals were intraperitoneally inoculated with P. brasiliensis (strain 18) and killed 6, 12 and 24 hours or 3, 7 and 14 days after infection. In these periods, fragments from their spleen, liver and lung were removed for evaluation of the infection level by fungal cells, assessment of macrophagic activity by peritoneal and splenic macrophages - through the determination of nitric oxide (NO) concentrations and production of pro- and anti-inflammatory cytokines of lung and spleen homogenate supernatants. In the present study, it was observed that AIRmax lineages presented greater control of the infectious process than the AIRmin ones. Regarding NO production, AIRmax animals produced more metabolites in late periods, what may help control the infectious process. Concerning cytokine production, it was observed that the production of INF-gamma, TNF-alpha, IL-1, IL-6, IL-8 and IL-12 were increased in AIRmax lineages in most analyzed organs and periods, thus contributing to the greater resistance exhibited by such lineages against infection, except for IL-4 and IL-10 that showed decreased production in AIRmax lineage, reproducing its suppressive biological effect. From these results, it was observed that the AIRmax lineage was more effective in controlling the infectious process, with an important involvement of the analyzed cytokines. These findings are probably related to the genetically selected factors involved in the acute inflammatory response.
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Two groups of mice were infested with first stage larvae of the human bot-fly, Dermatobia hominis (Linnaeus Jr) (Diptera: Oestridae). In the first group, skin biopsies were carried out 1, 3, 5, 7, 10 and 18 days after infestation. The second group was also infested but had all the larvae removed 5 days after infestation. The mice in the latter group were reinfested 4 weeks later and skin biopsies were carried out 1, 3, 5, 7, 10 and 18 days after reinfestation. In the first group, an inflammatory reaction began slowly, the neutrophils being the main inflammatory cells, eosinophils being scarce. The reaction progressed with time, developing a necrotic halo around the larvae containing inflammatory cells surrounded by fibroblasts. The inflammation invaded the adjacent tissue. In the second group, the inflammatory reaction was intense on the day immediately after reinfestation, the pattern being changed by the presence of a large number of eosinophils. Activated fibroblasts surrounding the necrotic area around the larvae appeared 3 days after reinfestation in the second group and 7 days after infestation in the first group. The results demonstrated that the previous contact with the antigens elicited the early arrival of eosinophils, probably through the chemotactic factors liberated by mast cells in the anaphylactic reaction.
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
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The social wasp P. paulista is relatively common in southeast Brazil causing many medically important stinging incidents. The seriousness of these incidents is dependent on the amount of venom inoculated by the wasps into the victims, and the characteristic envenomation symptoms are strongly dependent on the types of peptides present in the venom. In order to identify some of these naturally occurring peptides available in very low amounts, an analytical protocol was developed that uses a combination of reversed-phase and normal-phase high-performance liquid chromatography (HPLC) of wasp venom for peptide purification, with matrix-assisted laser desorption/ionization time-of-flight post-source decay mass spectrometry (MALDI-Tof-PSD-MS) and low-energy collision-induced dissociation (CID) in a quadrupole time-of-flight tandem mass spectrometry (QTof-MS/MS) instrument for peptide sequencing at the sub-picomole level. The distinction between Leu and Ile was achieved both by observing d-type fragment ions obtained under CID conditions and by comparison of retention times of the natural peptides and their synthetic counterparts (with different combinations of I and/or L at N- and C-terminal positions). To distinguish the isobaric residues K and Q, acetylation of peptides was followed by Q-Tof-MS analysis. The primary sequences obtained were INWLKLGKMVIDAL-NH2 (MW 1611.98Da) and IDWLKLGKMVMDVL-NH2 (MW 1658.98Da). Micro-scale bioassay protocols characterized both peptides as presenting potent hemolytic action, mast cell degranulation, and chemotaxis of poly-morphonucleated leukocyte (PMNL) cells. The primary sequences and the bioassay results suggest that these toxins constitute members of a new sub-class of mastoparan toxins, directly involved in the occurrence of inflammatory processes after wasp stinging. Copyright (C) 2004 John Wiley Sons, Ltd.
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Extracts from Lychnophora species are traditionally used in Brazil as anti-inflammatory, and to treat bruise, pain and rheumatism. The ethanolic extract of aerial parts of five species of Lychnophoras and one specie of Lychnophoriopsis were examined for the antinociceptive (hot-plate and writhing tests) and anti-inflammatory (carrageenan-induced paw oedema test) activity in mice, by oral and topical routes, respectively. In the hot-plate test, the Lychnophora pinaster (0.75 g/kg) and Lychnophora ericoides (1.50 g/kg) extracts significantly increased the time for licking of the paws. The species Lychnophora passerina, Lychnophoriopsis candelabrum and Lychnophora pinaster, using the dose of 0.75 g/kg, and Lychnophora ericoides and Lychnophora trichocarpha in both doses evaluated (0.75 and 1.50 g/kg) significantly reduced the number of writhes induced by acetic acid. The administration of Lychnophora pinaster and Lychnophora trichocarpha ointments, in both concentrations evaluated (5 and 10%, w/w), and Lychnophora passerina and Lychnophoriopsis candelabrum, in the concentration of 10%, significantly reduced the paw oedema measured 3 h after carrageenan administration, suggesting, for the first time, an anti-inflammatory activity upon topical administration of these species. The present work comparatively demonstrated the antinociceptive and anti-inflammatory activities of some Brazilian Lychnophoras. (C) 2007 Elsevier B.V. All rights reserved.