17 resultados para intermediate agents

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


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Para estimar e analisar os custos de comercialização e identificar locais e formas de comercialização do caju, foram realizadas, durante o ano de 2000/01, entrevistas com produtores, técnicos da extensão rural, agentes intermediários e pesquisadores de órgãos públicos. Também foram levantadas informações na Companhia de Entrepostos e Armazéns Gerais de São Paulo (CEAGESP). Os custos agregados pelo segmento da comercialização devem-se, em grande parte, às despesas com o transporte até os grandes centros atacadistas, e também à comissão definida pelo atacadista. Para o produtor da região Noroeste do Estado de São Paulo, o ideal seria direcionar sua produção para os meses de janeiro a junho, garantindo assim melhores preços e com isso resultados mais satisfatórios.

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Aim To evaluate ex vivo effectiveness of the three formulations of bleaching materials for intracoronal bleaching of root filled teeth using the walking bleach technique.Methodology Extracted premolar teeth were stained artificially with human blood. After biomechanical preparation, the root canals were filled and a 3-mm thick intermediate base of zinc phosphate cement was placed at the level of the cementoenamel junction. The teeth were divided into four groups (n = 12): C (control, without bleaching material), A1 (sodium perborate + distilled water), A2 (sodium perborate + 10% carbamide peroxide) and A3 (sodium perborate + 35% carbamide peroxide). The bleaching materials were changed at 7 and 14 days. Evaluation of shade was undertaken with aid of the VITA Easyshade (TM) (Delta E*ab) and was performed after tooth staining and at 7, 14 and 21 days after bleaching, based on the CIELAB system. Data were analysed by ANOVA for repeated measurements, Tukey and Dunnett tests (alpha = 0.05).Results The Tukey test revealed that group A1 (10.58 +/- 4.83 Delta E*ab) was statistically different from the others (A2, 19.57 +/- 4.72 Delta E*ab and A3, 17.58 +/- 3.33 Delta E*ab), which were not different from each other. At 7 days: A1 was significantly different from A2; at 14 and 21 days: A2 and A3 were significantly better than A1; the Dunnett test revealed that the control group was different from A1, A2 and A3 at all periods (P < 0.05).Conclusion Sodium perborate associated with both 10% and 35% carbamide peroxide was more effective than when associated with distilled water.

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Purpose: To evaluate the influence of three different adhesives, each used as an intermediary layer, on microleakage of sealants applied under condition of salivary contamination. Materials and Methods: Six different experimental conditions were compared, 3 with adhesives and 3 without. After prophylaxis and acid etching of enamel, salivary contamination was placed for 10 s. In Group SC the sealant was applied after saliva without bonding agent and then light-cured. In Group SCA, after saliva, the surface was air dried, and then the sealant was applied and cured. In Groups ScB, SB and PB, a bonding agent (Scotchbond Dual Cure/3M, Single Bond/3M and Prime & Bond 2.1/Dentsply, respectively) was applied after the saliva and prior to the sealant application and curing. After storage in distilled water at 37°C for 24 hrs, the teeth were submitted to 500 thermal cycles (5°C and 55°C), and silver nitrate was used as a leakage tracer. Leakage data were collected on cross sections as percentage of total enamel-sealant interface length. Representative samples were evaluated under SEM. Results: Sealants placed on contaminated enamel with no bonding agent showed extensive microleakage (94.27% in SC; 42.65% in SCA). The SEM revealed gaps as wide as 20 μm in areas where silver nitrate leakage could be visualized. In contrast, all bonding agent groups showed leakage less than 6.9%. Placement of sealant with a dentin-bonding agent on contaminated enamel significantly reduced microleakage (P< 0.0001). The use of a bonding agent as an intermediary layer between enamel and sealant significantly reduced saliva's effect on sealant microleakage.

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Lung cancer is a leading cause of death in developed countries. Although smoking cessation is a primary strategy for preventing lung cancer, former smokers remain at high risk of cancer. Accordingly, there is a need to increase the efficacy of lung cancer prevention. Poor bioavailability is the main factor limiting the efficacy of chemopreventive agents. The aim of this study was to increase the efficacy of cancer chemopreventive agents by using lipid nanoparticles (NPs) as a carrier. This study evaluated the ability of lipid NPs to modify the pharmacodynamics of chemopreventive agents including N-acetyl-L-cysteine, phenethyl isothiocyanate and resveratrol (RES). The chemopreventive efficacy of these drugs was determined by evaluating their abilities to counteract cytotoxic damage (DNA fragmentation) induced by cigarette smoke condensate (CSC) and to activate protective apoptosis (annexin-V cytofluorimetric staining) in bronchial epithelial cells both in vitro and in ex vivo experiment in mice. NPs decreased the toxicity of RES and increased its ability to counteract CSC cytotoxicity. NPs significantly increased the ability of phenethyl isothiocyanate to attenuate CSC-induced DNA fragmentation at the highest tested dose. In contrast, this potentiating effect was observed at all tested doses of RES, NPs dramatically increasing RES-induced apoptosis in CSC-treated cells. These results provide evidence that NPs are highly effective at increasing the efficacy of lipophilic drugs (RES) but are not effective towards hydrophilic agents (N-acetyl-L-cysteine), which already possess remarkable bioavailability. Intermediate effects were observed for phenethyl isothiocyanate. These findings are relevant to the identification of cancer chemopreventive agents that would benefit from lipid NP delivery.

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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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DNA analysis by molecular techniques has significantly expanded the perspectives of the study and understanding of genetic variability in molluscs that ere vectors of schistosomiasis. In tire present study, the genetic variability of susceptible and resistant B. tenagophila strains to S. mansoni infection was investigated using amplification of their genomic DNA by RAPD-PCR. The products were analyzed by PAGE and stained with silver. The results showed pdymorphism between tested strains with four different primers. We found two bonds of 1,900 and 3,420 bp that were characteristic of the susceptible strains with primer 2. The primers 9 end 10 identified a single polymorphic bond that was also characteristic of (3,136 and 5,041 bp, respectively) susceptible snails. Two polymorphic bonds were detected by primer 15: one with 1 800 bp was characteristic of the resistant strain and the other with 1,700 do in the susceptible one. These results provide additional evidence showing that the RAPD-PCR technique is adequate for the study of polymorphisms in intermediate hosts snails of S. mansoni. The obtained results are expected to expend the knowledge about the genetic variability of the snails and to permit the future identification of genomic sequences specifically related to the resistance/susceptibility of Biompholario to the larval forms of S. mansoni.

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The Topliss method was used to guide a synthetic path in support of drug discovery efforts toward the identification of potent antimycobacterial agents. Salicylic acid and its derivatives, p-chloro, p-methoxy, and m-chlorosalicylic acid, exemplify a series of synthetic compounds whose minimum inhibitory concentrations for a strain of Mycobacterium were determined and compared to those of the reference drug, p-aminosalicylic acid. Several physicochemical descriptors (including Hammett's sigma constant, ionization constant, dipole moment, Hansch constant, calculated partition coefficient, Sterimol-L and -B-4 and molecular volume) were considered to elucidate structure-activity relationships. Molecular electrostatic potential and molecular dipole moment maps were also calculated using the AM1 semi-empirical method. Among the new derivatives, m-chlorosalicylic acid showed the lowest minimum inhibitory concentration. The overall results suggest that both physicochemical properties and electronic features may influence the biological activity of this series of antimycobacterial agents and thus should be considered in designing new p-aminosalicylic acid analogs.

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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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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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The activity of ten compounds isolated from Brazilian lichen over the release of hydrogen peroxide and nitric oxide was evaluated in the culture of peritoneal macrophage cells from mice. Salazinic, secalonic A and fumarprotocetraric acids were the compounds that induced the greatest release of H2O2, whereas 12R-usnic and diffractaic acids induced the release of NO. These results indicate that lichen products have potential immunological modulating activities. (C) 2004 Elsevier B.V. All rights reserved.

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With the objective of obtaining slow-acting isoniazid derivatives, of potential use as chemoprophylactics or chemotherapeutics in tuberculosis, the micelle-forming copolymer of poly(ethylene glycol)-poly(aspartic acid) prodrug with isoniazid was synthesized. The derivative obtained was found to be active in Mycobacterium Il(tuberculosis culture, with a minimal inhibitory concentration (MIC) 5.6 times lower than that of the tuberculostatic drug.

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Nitroaromatic compounds such as nifuroxazide are used in many human enteropathogenic bacteria infections without causing an increase in the plasmidial antibiotic resistance of the aerobic Gram-negative intestinal Enterobacteriaceae. For these reasons, these compounds have been synthesized using the rational approach of Topliss' decision tree. Generally. this approach allows us to obtain the most active derivative from the series in a few steps. These compounds were tested against Mycobacterium tuberculosis in vitro and the most active of the series identified. A new lead for potential tuberculostatic activity has been predicted and will be used in further QSAR studies. (C) 2002 Elsevier B.V. Ltd. All rights reserved.