Co-stressors chilling and high light increase photooxidative stress in diuron-treated red alga Kappaphycus alvarezii but with lower involvement of H2O2

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

Evaluation of the influences of solution path length and additives concentrations on the solar photo-Fenton degradation of 4-chlorophenol using multivariate analysis

This study reports the photodegradation of 4-chlorophenol (4-CP) in aqueous solution by the photo-Fenton process using solar irradiation. The influence of solution path length, and Fe(NO3)(3) and H2O2 concentrations on the degradation of 4-CP is evaluated by response surface methodology. The degradation process was monitored by the removal of total organic carbon (TOC) and the release of chloride ion. The results showed a very important role of iron concentration either for TOC removal or dechlorination. on the other hand, a negative effect of increasing solution path length on mineralization was observed, which can be compensated by increasing the iron concentration. This permits an adjustment of the iron concentration according to the irradiation exposure area and path length (depth of a tank reactor). Under optimum conditions of 1.5 mM Fe(NO3)(3), 20.0 mM H2O2 and 4.5 cm solution path length, 17 min irradiation under solar light were sufficient to reduce a 72 mg C L-1 solution of 4-CP by 91 (c) 2006 Elsevier B.V. All rights reserved.

Homogeneous photodegradation of CI Reactive Blue 4 using a photo-Fenton process under artificial and solar irradiation

The oxidation of C.I. Reactive Blue 4 (RB4) by photo-Fenton process mediated by lerrioxalate was investigated under artificial and solar irradiation. The RB4 degradation in acidic medium (pH 2.5) was evaluated by the decrease in Total Organic Carbon (TOC) content and color, measured by the decrease in chromophore absorption band (600 nm). The influence of ferrioxalate and H2O2 concentrations on the dye degradation was studied and best results were obtained using 1.0 mM ferrioxalate and 10 nM of hydrogen peroxide. Under these experimental conditions, 80% of TOC and 100% of color removal were obtained for a 0.1 mM RB4 dye in 35 min of solar irradiation. (c) 2006 Elsevier Ltd. All rights reserved.

Participação do receptor toll-like4 na resposta imune durante a esporotricose ecperimental

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Degradação de fármacos por processo foto-Fenton e ferro metálico

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Desenvolvimento, otimização e avaliação da viabilidade dos processos fenton e foto-fenton para a remediação de solos contaminados

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Effect of therapeutic plasma concentrations of non-steroidal anti-inflammatory drugs on the production of reactive oxygen species by activated rat neutrophils

The release of reactive oxygen specie (ROS) by activated neutrophil is involved in both the antimicrobial and deleterious effects in chronic inflammation. The objective of the present investigation was to determine the effect of therapeutic plasma concentrations of non-steroidal anti-inflammatory drugs (NSAIDs) on the production of ROS by stimulated rat neutrophils. Diclofenac (3.6 µM), indomethacin (12 µM), naproxen (160 µM), piroxicam (13 µM), and tenoxicam (30 µM) were incubated at 37ºC in PBS (10 mM), pH 7.4, for 30 min with rat neutrophils (1 x 10(6) cells/ml) stimulated by phorbol-12-myristate-13-acetate (100 nM). The ROS production was measured by luminol and lucigenin-dependent chemiluminescence. Except for naproxen, NSAIDs reduced ROS production: 58 ± 2% diclofenac, 90 ± 2% indomethacin, 33 ± 3% piroxicam, and 45 ± 6% tenoxicam (N = 6). For the lucigenin assay, naproxen, piroxicam and tenoxicam were ineffective. For indomethacin the inhibition was 52 ± 5% and diclofenac showed amplification in the light emission of 181 ± 60% (N = 6). Using the myeloperoxidase (MPO)/H2O2/luminol system, the effects of NSAIDs on MPO activity were also screened. We found that NSAIDs inhibited both the peroxidation and chlorinating activity of MPO as follows: diclofenac (36 ± 10, 45 ± 3%), indomethacin (97 ± 2, 100 ± 1%), naproxen (56 ± 8, 76 ± 3%), piroxicam (77 ± 5, 99 ± 1%), and tenoxicam (90 ± 2, 100 ± 1%), respectively (N = 3). These results show that therapeutic levels of NSAIDs are able to suppress the oxygen-dependent antimicrobial or oxidative functions of neutrophils by inhibiting the generation of hypochlorous acid.

Anti-inflammatory activity of Alchornea triplinervia ethyl acetate fraction: Inhibition of H2O2, NO and TNF-alpha

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

Serum iron and plasma fibrinogen concentrations as indicators of systemic inflammatory diseases in horses

Background: Detection of systemic inflammation, which is important for proper diagnosis and prompt treatment, can be challenging.Hypothesis: Measurement of plasma iron concentration is a sensitive method for detecting systemic inflammation in horses compared with measurements of plasma Fibrinogen concentration, a traditional marker for inflammation in the horse.Animals: Ninety-seven horses hospitalized with diseases causing systemic inflammation, 22 horses with localized inflammation, and 12 clinically normal horses were included in this study.Methods: A retrospective study was made on hospitalized horses that had both plasma iron and fibrinogen concentrations measured on hospital admission.Results: Plasma iron concentration was lower in horses with systemic inflammation (64 +/- 45 mu g/dL) than the reference interval minimum (105 mu g/dL) and were significantly lower (P = .001) than the value in a group of horses with local inflammation (123 +/- 45 mu g/dL) and in healthy transported horses (143 +/- 29 mu g/dL). Low plasma iron and high fibrinogen concentrations were both sensitive indicators of systemic inflammation in horses with sensitivity of 90 and 82%, respectively. There was a similar correlation between either continued decreases in iron concentration (R-sp of 0.239) or increases in fibrinogen concentration (R-sp of 0.280) during hospitalization and a worse prognosis.Conclusions and Clinical Importance: Measurement of plasma iron concentration better reflected acute inflammation than did fibrinogen concentration.

Simple and fast spectrophotometric determination of H2O2 in photo-Fenton reactions using metavanadate

This work proposes a spectrophotometric method for the determination of hydrogen peroxide during photodegradation reactions. The method is based on the reaction of H2O2 with amonium metavanadate in acidic medium, which results in the formation of a red-orange color peroxovanadium cation, with maximum absorbance at 450 nm. The method was optimized using the multivariate analysis providing the minimum concentration of vanadate (6.2 mmol L-1) for the maximum absorbance signal. Under these conditions, the detection limit is 143 mu mol L-1. The reaction product showed to be very stable for samples of peroxide concentrations up to 3 mmol L-1 at room temperature during 180 h. For higher concentrations however, samples must be kept refrigerated (4 degrees C) or diluted. The method showed no interference of Cl- (0.2-1.3 mmol L-1), NO3- (0.3-1.0 mmol L-1), Fe3+, (0.2-1.2 mmol L-1) and 2,4-dichlorophenol (DCP) (0.2-1.0 mmol L-1). When compared to iodometric titration, the vanadate method showed a good agreament. The method was applied for the evaluation of peroxide consumption during photo-Fenton degradation of 2,4-dichlorophenol using blacklight irradiation. (c) 2004 Elsevier B.V. All rights reserved.

Photodegradation of dichloroacetic acid and 2,4-dichlorophenol by ferrioxalate/H2O2 system

The photo-Fenton process using potassium ferrioxalate as a mediator in the photodegradation reaction of organochloride compounds in an aqueous medium was investigated. The influence of parameters such as hydrogen peroxide and ferrioxalate concentrations and initial pH, was evaluated using dichloroacetic acid (DCA) as a model compound under black-light lamp irradiation. An upflow annular photoreactor, operating in a single pass or recirculating mode was used during photodegradation experiments with artificial light. The extent of the release of chloride ions was used to evaluate the photodegradation reaction. The optimum pH range observed was 2.5-2.8. The efficiency of DCA dechlorination increased with increasing concentrations of H2O2 and potassium ferrioxalate, reaching a plateau after the addition of 6 and 1.5 mmol/L of those reagents, respectively. The total organic carbon (TOC) content in DCA and 2,4-dichlorophenol (DCP) solutions was compared with the chloride released after photodegradation. The influence of natural solar light intensity, measured at 365 nm, was evaluated for the dechlorination of DCA on typical summer's days showing a linear dependency. The photodegradation of DCA using black-light lamp and solar irradiation was compared.

Citotoxicidade de Styrax camporum Pohl em macrófagos peritoneais e a liberação de H2O2

The immunological response includes wide contexts involving several cells, and the macrophage is crucial in the cellular immune response. Several stimuli to macrophage membrane may induce the liberation of H2O2, contributing to antibacterial and cytotoxicical actions. Nowadays, there is a tendency to study natural products to verify their capacity of acting in the immune system. This study evaluated the citotoxicity of the bulk extract and the hexanic and acetic fractions extracted from Styrax camporum Pohl (Styracaceae) and the production of H2O2, on murine peritonal macrophages cultures exposed to fractions extracted from this plant. The results showed that the fraction HX 2 mg/ml produced the liberation of H 2O2 in high concentrations and to 4 mg/ml was observed high citotoxicity. The fractions AC did not produce the liberation of H 2O2 and EB was produced in low levels. We conclude that this HX is a potent stimulator of macrophage.

Effect of prostaglandins on the production of H2O2 and cytokines that modulate the fungicidal activity of human monocytes against Paracoccidioides brasiliensis

Human monocytes lack fungicidal activity against high virulent strains of Paracoccidioides brasiliensis, the etiological agent of paracoccidioidomycosis, even after IFN-γ activation. However, monocytes treated with indomethacin (INDO) or INDO plus IFN-γ effectively killed this fungus, suggesting an inhibitory role of prostaglandins in this process. Thus, the purpose of this work was to test if this regulatory effect of prostaglandin was associated with alterations on H2O2 production and/or on modulatory cytokines levels, such as TNF-α, IL-10, and IL-6. Peripheral blood monocytes obtained from 10 healthy donors were incubated for 18 hours in the presence or absence of IFN-γ, INDO, or IFN-γ plus INDO, and further challenged with a high virulent strain of P. brasiliensis (Pb18) for 4 hours. Then, the monocytes cultures were evaluated for H2O2 release and fungicidal activity calculated by counting the colony forming units after plating. Moreover, on supernatants of the same cultures, TNF-α, IL-10, IL-6, and PGE2 concentrations were evaluated by ELISA. Monocytes treated with INDO or INDO plus IFN-γ presented higher fungicidal activity associated with the release of higher levels of H2O2 and TNF-α, but lesser levels of PGE2, when compared to nontreated cells. However, the levels of IL-10 and IL-6 were similar between treated and nontreated cells. The results suggest that human monocytes when challenged with high virulent strains of P. brasiliensis produce prostaglandins that inhibit the fungicidal activity of these cells by reducing H2O2 and TNF-α levels.

Concentrations of and application protocols for hydrogen peroxide bleaching gels: Effects on pulp cell viability and whitening efficacy

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

Protective Effect of Alpha-Tocopherol Isomer from Vitamin E against the H2O2 Induced Toxicity on Dental Pulp Cells

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)