In paracoccidioidomycosis, a systemic mycosis caused by the fungusParacoccidioides brasiliensis (Pb), studies have focused on the role of neutrophils that are involved in the primary response to the fungus. Neutrophil functions are regulated by pro-and anti-inflammatory cytokines. Molecular mechanisms involved in this process are not fully understood, but there are strong evidences about the involvement of toll-like receptors (TLRs). We aimed at evaluating TLR2 and TLR4 expression on human neutrophils activated by GM-CSF, IL-15, TNF-alpha or IFNgamma and challenged with a virulent strain of P. brasiliensis (Pb18). Moreover, we asked if these receptors have a role on fungicidal activity, H 2 O 2 and IL-6, IL-8, TNFalpha and IL-10 production, by activating and challenging cells. All cytokines increased TLR2 and TLR4 expression. Pb18 also increased TLR2 expression, inducing an additional cytokine effect. On the contrary, it inhibited TLR4 expression.All cytokines increased neutrophil fungicidal activity and H 2 O 2 production; however, this process was not associated with TLR2 or TLR4. Neutrophil activation by GM-CSF and TNF-alpha resulted in a significant increase of IL-8 production, while IL-15 and IFN-alpha have no effect. Pb18 also augmented IL-8 expression, inducing an additional effect to that of cytokines. None of the cytokines activated neutrophils by releasing IL-10. This cytokine was only detected after Pb18 challenge. Interestingly, IL-8 and IL-10 production involved TLR2 and mainly TLR4 modulation. The present results suggest that Pb18 interaction with neutrophils through TLR2 and TLR4 with

Paracoccidioides brasiliensis is the agent of paracoccidioidomycosis, the most prevalent deep mycosis in Latin America. Production of eicosanoids during fungal infections plays a critical role on fungal biology as well as on host immune response modulation. The purpose of our study was to assess whether P. brasiliensis strains with different degree of virulence (Pb18, Pb265, Bt79, Pb192) produce prostaglandin E(x) (PGE(x)). Moreover, we asked if P. brasiliensis could use exogenous sources of arachidonic acid (AA), as well as metabolic pathways dependent on cyclooxygenase (COX) enzyme, as reported for mammalian cells. A possible association between this prostanoid and fungus viability was also assessed. Our results showed that all strains, independently of their virulence, produce high PGE(x) levels on 4 h culture that were reduced after 8 h. However, in both culture times, higher prostanoid levels were detected after supplementation of medium with exogenous AA. Treatment with indomethacin, a COX inhibitor, induced a reduction on PGEx, as well as in fungus viability. The data provide evidence that P. brasiliensis produces prostaglandin-like molecules by metabolizing either endogenous or exogenous AA. Moreover, the results suggest the involvement of these mediators on fungal viability.

In paracoccidioidomycosis, a systemic mycosis caused by the fungus Paracoccidioides brasiliensis (Pb), studies have focused on the role of neutrophils that are involved in primary response to the fungus. Neutrophil functions are regulated by pro‐ and anti‐inflammatory cytokines. The molecular mechanisms involved in this process are not fully understood, but there are strong evidences about the involvement of toll‐like receptors (TLR). We aimed at evaluating TLR2 and TLR4 expression on human neutrophils activated with GM‐CSF, IL‐15, TNF‐α or IFN‐γ and challenged with a virulent strain of P. brasiliensis (Pb18). Moreover, we asked if these receptors have a role on fungicidal activity, H2O2 and IL‐6, IL‐8, TNF‐α and IL‐10 production by activated and challenged cells. All cytokines increased TLR2 and TLR4 expression. Pb18 also increased TLR2 expression inducing an additional effect to that of cytokines. On the contrary, it inhibited TLR4 expression. All cytokines increased neutrophil fungicidal activity and H2O2 production, but this process was not associated with TLR2 or TLR4. Neutrophils activation with GM‐CSF and TNF‐α resulted in a significative increase in IL‐8 production, while IL‐15 and IFN‐γ have no effect. Pb18 alone also increased IL‐8 production. None of the cytokines activated neutrophils for IL‐10 release. This cytokine was only detected after Pb18 challenge. Interestingly, IL‐8 and IL‐10 production involved TLR2 and mainly TLR4 modulation. Our data suggest that Pb18 uses TLR4 to gain access to human neutrophils. This interaction results in IL‐8 and IL‐10 production that may be considered as a pathogenic mechanism in paracoccidioidomycosis.

PURPOSE:To obtain a decellularized tracheal scaffold associating traditional approaches with the novel light-emitting diode (LED) proposal. METHODS:This study was performed with New Zealand adult rabbits weighing 3.0 -4.0 kg. Different protocols (22) were used combining physical (agitation and LED irradiation), chemical (SDS and Triton X-100 detergents), and enzymatic methods (DNase and RNase). RESULTS:Generally, the cells surrounding soft tissues were successfully removed, but none protocol removed cells from the tracheal cartilage. However, longer protocols were more effective. The cost-benefits relation of the enzymatic processes was not favorable. It was possible to find out that the cartilaginous tissue submitted to the irradiation with LED 630nm and 475 nm showed an increased number of gaps without cells, but several cells were observed to be still present. CONCLUSION:The light-emitting diode is a promising tool for decellularization of soft tissues.

Paracoccidioides brasiliensis is the etiological agent of paracoccidioidomycosis, a deep mycosis endemic in Latin America. Studies to elucidate the host-parasite relationship in this mycosis have demonstrated that non-activated phagocytes fail to kill the etiologic agent. Investigations of human monocytes have shown that the lack of fungicidal activity is partially associated with the capacity of a high-virulence strain to induce PGE(2) release by these cells. This eicosanoid inhibits production of TNF-α, the cytokine involved in cell activation for release of H(2)O(2), the fungicidal metabolite. Cell priming with IFN-γ was shown to partially reverse this inhibitory effect. In this study, we asked whether monocyte challenge with a low-virulence strain of this fungus would also result in PGE(2) release and consequently inhibition of antifungal activities. We also assessed whether PGE(2,) besides inhibiting production of TNF-α, a monocyte-activating cytokine, also affects IL-10. The latter, in contrast to TNF-α is a monocyte-suppressing cytokine. Finally, we evaluated whether priming cells with other cytokines, namely TNF-α and GM-CSF, could be more effective than IFN-γ in reversing the PGE(2) inhibitory effect. The results revealed that the less virulent P. brasiliensis strain also induces human monocytes to release PGE(2). However, the inhibitory effect of PGE(2) was less pronounced when cells were challenged with this strain than with the more virulent one. It was also demonstrated that PGE(2), while inhibits TNF-α production, tends to increase IL-10 levels. Priming with GM-CSF or TNF-α was more effective than IFN-γ in compensating for the inhibitory PGE(2) effect, since these cytokines induce cells to produce higher H(2)O(2) and TNF-α levels.

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Este livro explica por meio de figuras produzidas a partir de scripts produzidos para programas computacionais de Bioinformática como ocorre a ligação entre a indometacina e a ciclo-oxigenase-2, sua enzima-alvo. Compreendendo como ocorre esta ligação é possível entender a ação anti-inflamatória da indometacina no organismo.

Seja bem-vindo, ao Museu Virtual de Ciências!!! Nesta coleção, em cada volume são apresentadas algumas das principais descobertas científicas. Neste terceiro volume, vamos conhecer um divertido jogo sobre a descoberta e a evolução do equipamento de ressonância magnética.