180 resultados para in vivo study


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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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The potential sequelae of intestinal infection with Yersinia enterocolitica include reactive arthritis, erythema nodosum, Reiter's syndrome and other autoimmune diseases. The role of the immune response in the pathogenesis of these diseases has not been fully defined, but autoimmune manifestations may be a consequence of the increase in autoantibodies as a result of polyclonal B-cell activation induced by Yersinia. We investigated the effects of Y enterocolitica 0:3 derivatives on B lymphocyte activation in vivo. Groups of five specific pathogen free (SPF) Swiss mice were inoculated with bacterial cell extract, Yersinia outermembrane proteins (Yops) or lipopolysaccharide (LPS) obtained from Y enterocolitica 0:3 and their immunoglobulin-secreting spleen cells were detected by isotype-specific protein A plaque assay. The presence of specific anti-Yersinia antibodies and autoantibodies was determined in mouse sera by ELISA. In all experiments a marked increase in the number of secretory cells of different isotypes was observed as early as the third day after inoculation. IgG and IgM anti-Yersinia antibodies were detected in the sera of all inoculated mice, and autoantibodies against myosin in the sera of those inoculated with bacterial cell extract. The sera from animals stimulated with LPS reacted with myelin, actin and laminin, while the sera from mice inoculated with Yops reacted with myelin, thyroglobulin and cardiolipin. These results suggest that SPF Swiss mice inoculated with any one of the Y enterocolitica derivatives tested exhibited polyclonal activation of B lymphocytes as a result of stimulation by various bacterial components and not only LPS stimulation.

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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It is know that endotoxin and various matrix metalloproteinases (MMPs) are involved in the development of periapical lesions. The purpose of this study was to evaluate and correlate the presence of endotoxins and MMP- 3, MMP-8 and MMP-9 in root canals of teeth with necrotic pulp and periapical lesion before, during and after the biomechanical preparation (PBM) using a combination of different irrigations solutions and intracanal dressing. Thirty-three single-root teeth with a diagnosis of pulp necrosis and periapical lesion radiographically visible were selected. Immediately after the coronal opening was collected the first sample from the root canal content. Then, all canals were prepared (cervical and middle thirds) by oscillatory instruments (EndoEze) and irrigated by 2.5% NaOCl. After, a manual preparation was made for the apical third and the teeth were divided into three groups according to the irrigation protocol: G1) 2.5% NaOCl (4 manual files); G2) 2.5% NaOCl (2 manual files) + [Ca (OH)2 0.14%] (2 manual files) and G3) 2.5% NaOCl (2 manual files) + polymyxin B (2 manual files). After the PBM, the second sample was collected; then the third collect was performed after using EDTA final flush. The fourth sample was collected 14 days after placing the dressing [2% chlorhexidine gel + Ca(OH)2]. Quantification of endotoxins was performed by a kinetic chromogenic lysate from amoebocytes of Limulus (LAL) and quantification of MMPs by ELISA assay. The results were analyzed statistically by Kruskal-Wallis and Dunn's test (5%) and ordinal Spearman correlation. Presence of endotoxin was observed in 100% of cases and G3 showed the greatest reduction of endotoxins from the 1st to the 2nd samples (97%), being statistically similar to G2 (84.2%) and different from G1 (49.4%) (p<0.05). The intracanal dressing promoted a significant reduction of endotoxin, no difference among the groups. For...

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Background The recent emergence of extensively multidrug-resistant Mycobacterium tuberculosis strains has further complicated the control of tuberculosis. There is an urgent need for the development of new molecular candidates antitubercular drugs. Medicinal plants have been an excellent source of leads for the development of drugs. The aim of this study was to evaluate the in vitro activity of 28 alcoholic extracts and essential oils of native and exotic Brazilian plants against Mycobacterium tuberculosis and to further study these extracts through chemical fractionation, the isolation of their constituents, and an evaluation of the in vivo acute toxicity of the active extracts. To the best of our knowledge this is the first chemical characterization, antituberculosis activity and acute toxicity evaluation of Annona sylvatica. Methods The anti-mycobacterial activity of these extracts and their constituent compounds was evaluated using the resazurin reduction microtiter assay (REMA). To investigate the acute toxicity of these extracts in vivo, female Swiss mice were treated with the extracts at doses of 500, 1000 and 2000 mg · kg-1 of body weight. The extracts were characterized by LC-MS, and the constituents were isolated and identified by chromatographic analysis of spectroscopic data. Results Of the 28 extracts, the methanol extract obtained from the leaves of Annona sylvatica showed anti-mycobacterial activity with an minimal inhibitory concentration (MIC) of 184.33 μg/mL, and the ethyl acetate fraction (EAF) resulting from liquid-liquid partitioning of the A. sylvatica extract showed an MIC of 115.2 μg/mL. The characterization of this extract by LC-MS identified flavonoids and acetogenins as its main constituents. The phytochemical study of the A. sylvatica EAF resulted in the isolation of quercetin, luteolin, and almunequin. Conclusions Among the compounds isolated from the EAF, luteolin and almunequin were the most promising, with MICs of 236.8 μg/mL (827.28 μM) and 209.9 μg/mL (328.48 μM), respectively. The acute administration of the EAF fraction in doses of 500, 1000, and 2000 mg · kg-1 of body weight did not cause signs of toxicity in the treated animals.

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Aims: This work aimed to assess how seed size, vials, vial sealing (in vitro), and substrate (in vivo) affect C. regium germination and emergence. This study shall contribute to the viable production of C. regium seedlings. Study Design: The experimental design used in these experiments was randomized. Place and Duration of Study: Department of Plant Biotechnology, Universidade de RibeirãoPreto, between March 2010 and December 2010. Methodology: This work has evaluated how seed size, vials, vial sealing (in vitro), and substrate (in vivo) influence the germination and emergence of C. regium. Results: The results showed that cultivation of C. regium seedlings from seeds is viable, irrespective of seed size. Vial oxygenation is an important parameter to consider in vitro, to obtain a larger number of normal seedlings. As for in vivo conditions, germination should be conducted in sand, to ensure a greater amount of young seedlings. Conclusion: The results presented here attested that it is possible to produce C. regium seedlings from seeds of any size both in vivo and in vitro conditions. In vitro, it is important to consider vial oxygenation, in order to obtain a greater amount of normal seedlings. In vivo, germination should be conducted in sand, to ensure production of a large quantity of seedlings.

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