10 resultados para protection mechanisms

em Repositório Institucional UNESP - Universidade Estadual Paulista "Julio de Mesquita Filho"


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For retarding carbon oxidation in refractories during the preheating of metallurgical furnaces, a ceramic coating, made mainly of sodium phosphosilicate and clay was developed. The coating presents high adherence to the substrate with no swelling. The coating was characterized by thermal analysis, X-ray diffraction at room temperature (XRD) and at high temperature (HTXRD), X-ray fluorescence and scanning electronic microscopy (SEM). The glass transition temperature is reached at 800 °C and only glassy phase is observed above this temperature. Thus the mechanism of protection seems to be the formation of a glassy phase on the surface of the refractory, and the coating tends to be more efficient at temperatures higher than 800 °C.

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

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Pós-graduação em Fisiopatologia em Clínica Médica - FMB

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Pós-graduação em Engenharia Elétrica - FEIS

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In the present work, the antitumor effect of fastuosain, a cysteine proteinase from Bromelia fastuosa, was investigated. In the intravenous model of lung colonization in C57Bl/6 mice, fastuosain and bromelain injected intraperitoneally were protective, and very few nodules of B16F10-Nex2 melanoma cells were detected. Tumor cells treated with fastuosain showed reduced expression of CD44 and decreased invasion through Matrigel, lost their cytoplasmic extensions and substrate adherence, and became round and detached, forming strongly bound cell clusters in suspension. Peritoneal cells recruited and activated by fastuosain treatment ( mainly monocytic cells and lymphocytes) migrated to the lung, where pulmonary melanoma metastases grew. Adoptive transference of peritoneal cells recruited by fastuosain had no protective effect against lung metastases in recipient mice. Treatment of green fluorescent protein - chimeric animals with fastuosain did not change the number of cells that migrated to the lung, compared to PBS-injected control mice, but the number of positive major histocompatibility complex class II cells increased with fastuosain treatment. Murine antibodies against fastuosain, bromelain, and cathepsins B and L cross-reacted in ELISA and recognized surface and cytoplasmic components expressed on B16F10-Nex2 cells. Anti-fastuosain antibodies were cytotoxic/lytic to B16F10-Nex2 cells. Antitumor effects of fastuosain involve mainly the direct effect of the enzyme and elicitation of protective antibodies.

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Flavonoid-rich Praxelis clematidea (Griseb.) R.M.King & H.Robinson (Asteraceae) is a native plant of South America. This study evaluates the gastroprotective activity and possible mechanisms for both the chloroform (CHCl3P) and ethyl acetate phases (AcOEtP) obtained from aerial parts of the plant. The activity was investigated using acute models of gastric ulcer. Gastric secretion biochemical parameters were determined after pylorus ligature. The participation of cytoprotective factors such as mucus, nitric oxide (NO), sulfhydryl (SH) groups, prostaglandin E2 (PGE 2), reduced glutathione (GSH), superoxide dismutase (SOD), glutathione peroxidase (GPx), glutathione reductase (GR), reduction of lipid peroxidation (malondialdehyde level), and polymorphonuclear infiltration (myeloperoxidase activity), was also investigated. CHCl3P (125, 250, and 500 mg/kg) and AcOEtP (62.5, 125, and 250 mg/kg) showed significant gastroprotective activity, reducing the ulcerative index by 75, 83, 88 % and 66, 66, 81 % for ethanol; 67, 67, 56 % and 56, 53, 58 % for a non-steroidal anti-inflammatory drug (NSAID); and 74, 58, 59 % and 64, 65, 61 % for stress-induced gastric ulcer, respectively. CHCl3P (125 mg/kg) and AcOEtP (62.5 mg/kg) significantly reduced the ulcerative area by 78 and 83 %, respectively, for the ischemia-reperfusion model. They also did not alter the biochemical parameters of gastric secretion, the GSH level or the activities of SOD, GPx or GR. They increased the quantity of gastric mucus, not dependent on NO, yet dependent on SH groups, and maintained PGE2 levels. The P. clematidea phases demonstrated gastroprotective activity related to cytoprotective factors. © 2012 The Japanese Society of Pharmacognosy and Springer.

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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When calcinine (A-23187) (2 mu M), a known Ca2+ ionophore, is present, a significant protection is observed to a mitochondrial suspension undergoing lipid peroxidation by Fe2+-citrate complex. A-23187 can remove Ca2+, which seems to have an important role in the lipid peroxidation process, from its 'lesive sites' and consequently preventing the damage. This information has importance in terms of knowing the mechanisms and avoiding the damages of lipid peroxidation that occur in some pathological cases such as tumor promotion and hemochromatosis.