Consulta: subjectFacets:"Hydrogen peroxide"
Registros recuperados: 36
Data/hora: 13/06/2024 04:35:42

Effects of H2O2, Fe2+ and Fe3+ on curcumin-induced chromosomal aberrations in CHO cells
Provedor de dados: 74
Autores: Antunes,Lusânia Maria Greggi; Araújo,Maria Cristina Paiva; Dias,Francisca da Luz; Takahashi,Catarina Satie.
The effects of H2O2, Fe2+ and Fe3+ on curcumin-induced clastogenicity were evaluated in CHO cells. Curcumin combined with H2O2 did not increase the chromosomal aberrations more than expected based on a simple additive effect. In contrast, the combination of curcumin-Fe significantly decreased the total number of chromosomal aberrations and the number of abnormal metaphases. The clastogenicity of curcumin may be related to its pro-oxidant properties and its ability to generate free radicals.
Tipo: Info:eu-repo/semantics/article
Palavras-chave: CHO; Chromosomal aberrations; Curcumin; Hydrogen peroxide; Mutagenesis.
Ano: 2005
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-47572005000100028

Several pathways of hydrogen peroxide action that damage the E. coli genome
Provedor de dados: 74
Autores: Asad,Nasser Ribeiro; Asad,Lidia Maria Buarque Oliveira; Almeida,Carlos Eduardo Bonacossa de; Felzenszwalb,Israel; Cabral-Neto,Januário Bispo; Leitão,Alvaro Costa.
Hydrogen peroxide is an important reactive oxygen species (ROS) that arises either during the aerobic respiration process or as a by-product of water radiolysis after exposure to ionizing radiation. The reaction of hydrogen peroxide with transition metals imposes on cells an oxidative stress condition that can result in damage to cell components such as proteins, lipids and principally to DNA, leading to mutagenesis and cell death. Escherichia coli cells are able to deal with these adverse events via DNA repair mechanisms, which enable them to recover their genome integrity. These include base excision repair (BER), nucleotide excision repair (NER) and recombinational repair. Other important defense mechanisms present in Escherichia coli are OxyR and SosRS...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Hydrogen peroxide; Cross-adaptive response; Lethal synergism; Copper and iron.
Ano: 2004
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-47572004000200026

Réaction de réduction de l'oxygène sur les aciers inoxydables en eau de mer naturelle. Influence du biofilm sur les processus de corrosion
Provedor de dados: 5
Autores: Le Bozec, Nathalie.
iofilm development on stainless steels immersed in natural seawater can have prejudicial consequences on the resistance of these materials to corrosion . The goal of the present study was to get more precise information on the corrosion processes, and especially on the oxygen reduction reaction. As the reaction is linked to the stainless steel surface state, the characterisation of the oxides films (composition, structure, thickness...) is essential to understand the mechanisms and the oxygen reduction kinetic. The first aim of the study has been to correlate the oxygen reduction processes with the characteristics of the oxides layer as a function of the alloy surface treatment (mechanical polishing, electrochemical passivation and prereduction, chemical...
Tipo: Text
Palavras-chave: Hydrogen peroxide; Oxides layer; Biofilm; Oxygen reduction; Corrosion; Seawater; Stainless steels; Peroxyde d'hydrogène; Films d'oxydes; Biofilm; Réduction de l'oxygène; Corrosion; Eau de mer; Aciers inoxydables.
Ano: 2000
URL: http://archimer.ifremer.fr/doc/2004/these-223.pdf

The decomposition of hydrogen peroxide by marine phytoplankton
Provedor de dados: 5
Autores: Wong, Gtf; Dunstan, Wm; Kim, Db.
All nine species of marine phytoplankton tested (a cyanobacterium: Synechococcus sp., three diatoms: Chaetoceros simplex, Thalassiosira oceanica and Skeletonema costatum, two prymnesiophytes: Pleurochrysis carterae and Isochrysis galbana, a prasinophyte: Tetraselmis sp., a green alga: Dunaliella tertiolecta, and a dinoflagellate: Amphidinium carterae) were able to decompose hydrogen peroxide in the dark. Since these phytoplankton species can be found widely in a variety of marine sub-environments, this indicates that the dark decomposition of hydrogen peroxide by phytoplankton is a general phenomenon in the oceans. The decomposition rates were first order with respect to the concentration of hydrogen peroxide and biomass. The second-order rate constants...
Tipo: Text
Palavras-chave: Phytoplancton marin; Peroxyde d'hydrogène; Oxydo-réduction; Marine phytoplankton; Hydrogen peroxide; Oxidation-reduction.
Ano: 2003
URL: http://archimer.ifremer.fr/doc/00322/43276/43007.pdf

Development of a comet-FISH assay for the detection of DNA damage in hemocytes of Crassostrea gigas
Provedor de dados: 5
Autores: Perez Garcia, Maria Concepcion; Rouxel, Julien; Akcha, Farida.
In this work, the DNA-damaging effect of hydrogen peroxide on the structural integrity of nucleolar organizer regions (NORs) was studied for the first time by comet-FISH in the Pacific oyster Crassostrea gigas. Global DNA damage was assessed in hemocytes using an alkaline version of the comet assay. Next, NOR sensitivity was analysed by mapping major rDNA repeat unit by fluorescence in situ hybridisation (FISH) on the same comet slides. Exposure of hemocytes to 100 μM of hydrogen peroxide induced a significant increase in both DNA damage and number of FISH-signals of major ribosomal genes versus the control. Moreover, a significant positive correlation was shown between DNA damage as measured by the comet assay (percentage of DNA in comet tail) and the...
Tipo: Text
Palavras-chave: Crassostrea gigas; Hydrogen peroxide; Comet assay; Comet-FISH; Genotoxicity.
Ano: 2015
URL: https://archimer.ifremer.fr/doc/00250/36157/34712.pdf

The ABTS-HRP System as an Alternative Method to RRDE for the Determination of the Selectivity of the Oxygen Reduction Reaction
Provedor de dados: 5
Autores: Cheng, Xi; Challier, Lylian; Etcheberry, Arnaud; Noel, Vincent; Perez, Henri.
A 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonate) (ABTS)-H2O2-peroxidase system was involved to study the oxygen reduction reaction (ORR) selectivity in acid medium. The average number of electron transferred per oxygen molecule (n) was calculated by measuring the quantity of H2O2 produced during the oxygen reduction reaction, taking advantage of the high activity of peroxidase enzyme coupled with the ABTS chromogen. The method was validated using electrode materials for which the electron pathway is established. It is simple, accurate and can be used on various kind of electrode structure.
Tipo: Text
Palavras-chave: ORR; Selectivity; Hydrogen peroxide; Porous electrodes.
Ano: 2012
URL: https://archimer.ifremer.fr/doc/00692/80365/83471.pdf

New Insight into Antimicrobial Compounds from Food and Marine-Sourced Carnobacterium Species through Phenotype and Genome Analyses
Provedor de dados: 5
Autores: Begrem, Simon; Ivaniuk, Flora; Gigout Chevalier, Frederique; Kolypczuk, Laetitia; Bonnetot, Sandrine; Leroi, Francoise; Grovel, Olivier; Delbarre-ladrat, Christine; Passerini, Delphine.
Carnobacterium maltaromaticum and Carnobacterium divergens, isolated from food products, are lactic acid bacteria known to produce active and efficient bacteriocins. Other species, particularly those originating from marine sources, are less studied. The aim of the study is to select promising strains with antimicrobial potential by combining genomic and phenotypic approaches on large datasets comprising 12 Carnobacterium species. The biosynthetic gene cluster (BGCs) diversity of 39 publicly available Carnobacterium spp. genomes revealed 67 BGCs, distributed according to the species and ecological niches. From zero to six BGCs were predicted per strain and classified into four classes: terpene, NRPS (non-ribosomal peptide synthetase), NRPS-PKS (hybrid...
Tipo: Text
Palavras-chave: Lactic acid bacteria; Antimicrobial activity; Carnobacteriumspp; Hydrogen peroxide; Bacteriocin; RiPP; NRPS; Terpene; Natural product; Genome mining.
Ano: 2020
URL: https://archimer.ifremer.fr/doc/00641/75335/75999.pdf

Immunomodulatory action of propolis on macrophage activation
Provedor de dados: 79
Autores: ORSI,R.O.; FUNARI,S.R.C.; SOARES,A.M.V.C.; CALVI,S.A.; OLIVEIRA,S.L.; SFORCIN,J.M.; BANKOVA,V.
Propolis has been the subject of several recent studies, with the aim of elucidating its biological and pharmacological properties. Propolis has a well-known antimicrobial activity as well as antioxidant, antitumoral, antiinflammatory, and regenerative properties, but literature about its effects on the immune response is scarce. The goal of this work was to evaluate the propolis effect on macrophage activation by oxygen (H2O2) and nitrogen (NO) metabolite determination. Propolis was produced by africanized honeybees and hydroalcoholic solutions were prepared at different concentrations. Peritoneal macrophages were obtained from male BALB/c mice and culture cells were stimulated in vitro with propolis or interferon-gamma (IFN-gamma). In the in vivo assay,...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Propolis; Macrophages; Hydrogen peroxide; Nitric oxide.
Ano: 2000
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0104-79302000000200006

Physical constraints of bath treatments of Atlantic salmon (Salmo salar) with a sea lice burden (Copepoda: Caligidae)
Provedor de dados: 16
Autores: Treasurer, James W.; Grant, Andrew; Davis, Paul J.
Licensed medicines available in the U.K. for treating Atlantic salmon infested with sea lice, dichlorvos, azamethiphos, and hydrogen peroxide, can only be administered by bath application. Adverse reactions have been reported to bath treatments including mortalities, inappetance, reduction in growth and reduced louse sensitivity to dichlorvos. The physical constraints of bath treatments are examined and improvements recommended. Oxygen saturation was adequate during treatments but declined rapidly when the tarpaulin was removed. A chemical marker dispersed uniformally both horizontally and vertically in a cage within 5 mins of dispensing indicating dispersal of a medicine is rapid and adequate during treatment. The range in enclosed volumes in 86...
Tipo: Article / Letter to the editor
Palavras-chave: Sea lice; Atlantic salmon; Salar; Bath application; Dichlorvos; Hydrogen peroxide.
Ano: 2000
URL: http://www.repository.naturalis.nl/record/534338

Evaluation of pregerminative treatments in gulupa seeds (P. edulis f. edulis Sims).
Provedor de dados: 94
Autores: Camargo,María Antonia Martínez; Coronado,Ana Cruz Morillo; Mora,Edilberto Cepeda; Fernández,Sandra Yaneth Mesa.
Abstract  The genus Passiflora, commonly known as fruits of passion, includes numerous species, including gulupa (Passiflora edulis f. edulis), of nutracetic and economic importance, both for consumption in nature and for its agro-industrial applicability. This research was developed to evaluate the effects of various pre-germinative treatments on the germination of gulupa seeds from the municipality of Ramiriquí (Boyacá), such as: exposure to hydrogen peroxide (H2O2), hypochlorite of sodium (NaOCl), gibberellic acid (GA3), distilled water imbibition and stratification at 4 °C, in varying concentrations and exposure times (24 and 48 hours), using an experimental design completely random, with three repetitions of 50 seed each one. Statistical analysis...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Passiflora; Gulupa; Germination; Hydrogen peroxide; Gibberellic acid; Sodium hypochlorite.
Ano: 2020
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-29452020000302003

Análise de processos alternativos na preparação de esqueletos para uso didático - DOI: 10.4025/actascibiolsci.v30i4.5876
Provedor de dados: 3
Autores: Silveira, Márcio José da; UEM; Teixeira, Gustavo Monteiro; UNESP/Botucatu; Oliveira, Edson Fontes de; UEM.
Laboratórios de Zoologia em Instituições de Pesquisa e Ensino têm demonstrado grande demanda por peças anatômicas para utilização em aulas práticas. No entanto, embora a bibliografia voltada para este tema não seja escassa, são raras as análises das relações custo/benefício de tais processos levando em consideração aspectos técnicos, como tempo de preparo, qualidade das peças e recursos materiais e humanos. Além de técnicas usualmente utilizadas, novos produtos de baixo custo, não-citados na literatura e encontrados facilmente no mercado, também foram testados. O principal objetivo deste trabalho foi a elaboração e organização de informações sobre técnicas alternativas de maceração de peças ósseas para coleções didáticas, realizando análises comparativas...
Palavras-chave: Maceração; Clarificação de esqueletos; Peróxido de hidrogênio; Suco de mamão maceration; Skeleton clarification; Hydrogen peroxide; Papaya juice.
Ano: 2008
URL: http://periodicos.uem.br/ojs/index.php/ActaSciBiolSci/article/view/5876

Experimental study on the performance of microwave assisted Hydrogen peroxide (H2O2) pretreatment of rice straw
Provedor de dados: 111
Autores: Singh, Renu; Tiwari, Sapna; Srivastava, Monika; Shukla, Ashish.
Biofuels are essentials as they can provide impending substitute for fossil fuels.  Rice straw has gained much attention from researchers because of its usability as a potential feedstock for bioethanol production.  Pre-treatments are crucial for enzymatic hydrolysis of rice straw.  In this study, combination of microwave and hydrogen peroxide (H2O2) is employed for the delignification of rice straw.  The Response surface methodology is used to optimize the pretreatment conditions with respect to H2O2 concentration, microwave power and irradiation time.  Under optimum conditions, maximum reducing sugar obtained through microwave assisted H2O2 is 1,453.64 µg/mL.  The chemical and morphological analysis ascertained that the surface of the samples treated...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Biofuel; Bio-ethanol  Biomass Enzymatic hydrolysis; Rice straw; Biofuel; Microwave; Hydrogen peroxide.
Ano: 2014
URL: http://www.cigrjournal.org/index.php/Ejounral/article/view/2633

Low concentrations of doxycycline attenuates FasL-induced apoptosis in HeLa cells
Provedor de dados: 48
Autores: Yoon,Jung Mi; Koppula,Sushruta; Huh,Se Jong; Hur,Sun Jin; Kim,Chan Gil.
BACKGROUND: Doxycycline (DC) has been shown to possess non-antibiotic properties including Fas/Fas Ligand (FasL)-mediated apoptosis against several tumor types in the concentration range of 10-40 &amp;#956;g/mL. However, the effect of DC in apoptotic signaling at much low concentrations was not studied. METHODS: The present study investigated the attenuation effect of low dose of DC on FasL-induced apoptosis in HeLa cell by the methods of MTT assay, fluorescence microscopy, DNA fragmentation, flow cytometry analysis, and western blotting. RESULTS AND CONCLUSION: In the present findings we showed that low concentration of DC (&lt;2.0 &amp;#956;g/mL) exhibited protective effects against FasL-induced apoptosis in HeLa cells. FasL treatment to HeLa cells...
Tipo: Journal article
Palavras-chave: Apoptosis; Caspase; Cisplatin; FasL; Hydrogen peroxide; Tetracycline.
Ano: 2015
URL: http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0716-97602015000100038

Hydrogen Peroxide Induced Oxidative Damage on Mineral Density and Mechanical Properties of Bone
Provedor de dados: 52
Autores: Cicek,Ekrem; Cakmak,Enes.
ABSTRACT Hydrogen peroxide is a common reactive oxygen species involved in the catalytic mechanism though it is toxic to cells due to its oxidative nature. This work investigates the effects of hydrogen peroxide induced oxidative damage on bone mineral density and mechanical properties of bone which is primarily a composite material composed primarily of collagen fibers and biominerals. Sheep leg bones were exposed to hydrogen peroxide for a week. Bone mineral density was measured by using dual energy X-ray absorptiometry. Compressive modulus tests were applied to bone in order to determine mechanical properties. Our study shows that the hydrogen peroxide induced oxidative stress has negative effects on bone mineral density and stiffness. We observed...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Bone mineral density; Compressive modulus; Hydrogen peroxide; Reactive oxygen species.
Ano: 2018
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1516-89132018000100320

Interference of a commercial catalase preparation in laccase and peroxidase activities
Provedor de dados: 52
Autores: Ballaminut,Nara; Yamanaka,Renata; Machado,Katia Maria Gomes.
The influence of commercial catalase preparations (fungal and bovine origin) on laccase and peroxidase activity assays was evaluated using enzymatic extracts obtained from several basidiomycetes grown under different culture conditions. No hydrogen peroxide was detected in the extracts. Inhibition of laccase activity by 40 to 80% was related to the catalase source. In addition, oxidation of the substrate (ABTS) by fungal catalase in the absence of the enzymatic extract from basidiomycetes was observed. The results demonstrated the need for the evaluation of interference of the commercial catalase preparation when its use was required in the reaction mixture.
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Peroxidase; Fungi; Basidiomycetes; Hydrogen peroxide; Enzymatic inhibition.
Ano: 2009
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1516-89132009000500017

Characterization of native and oxidized starches of two varieties of Peruvian carrot (Arracacia xanthorrhiza, B.) from two production areas of Paraná state, Brazil
Provedor de dados: 52
Autores: Matsuguma,Luciana Shizue; Lacerda,Luiz Gustavo; Schnitzler,Egon; Carvalho Filho,Marco Aurélio da Silva; Franco,Célia Maria Landi; Demiate,Ivo Mottin.
Two commercial varieties of Peruvian carrot ('Amarela de Carandaí' and 'Senador Amaral') were processed into flour, starch and bagasse and chemically evaluated. The starch was extracted, modified with H2O2 and characterized by the physicochemical methods. By using the methylene blue dyeing, the granules of the modified starches showed intense blue color. The carboxyl content, the reducing power and the amount of the water liberated from the pastes after the freeze-thawing were higher for the oxidized starches and their pastes were clearer than those of the native starches of the two varieties from the two production areas. The RVA viscoamylography showed that the modified starches had lower viscosities with differences between the varieties. In the thermal...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Peruvian carrot varieties; Starch; Hydrogen peroxide; Technological properties.
Ano: 2009
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1516-89132009000300022

The effect of phosphoethanolamine intake on mortality and macrophage activity in mice with solid ehrlich tumors
Provedor de dados: 52
Autores: Arruda,Maria Sueli Parreira de; Correa,Mara Adriana; Venturini,James; Félix,Maira Camila; Rosis,Ana Maria Bormio De; Galhiane,Mário Sérgio; Chierice,Gilberto Orivaldo; Costa,Maria Renata Sales Nogueira.
The aim of the present study was to examine the effect of a diet rich in synthetic PEtn on the metabolism macrophages of tumor-bearing mice. The results demonstrated that PEtn increased the animals' survival time. In addition, the treated animals released smaller amounts of hydrogen peroxide (H2O2) and nitric oxide (NO) than the non-treated animals, particularly after day 14. From the results it could be concluded that H2O2 and NO were important in the modulation of neoplastic growth, and pointed to a promising role of PEtn in the control of human neoplasms.
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Phosphoethanolamine; Ehrlich tumor; Nitric oxide; Hydrogen peroxide; Lipids.
Ano: 2011
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1516-89132011000600016

Efeito do etanol e do peróxido de hidrogênio intragástrico sobre a mucosa gástrica de rã (Rana catesbeiana, SHAW)
Provedor de dados: 52
Autores: Estivallet,Hidê Virgínia; Rodrigues,Maria Inês; Marroni,Norma Possa.
This work investigated the frog gastric mucosa response to hydrogen peroxide and ethanol induced injury. Acid and mucus secretion were estimated "in vitro" in control animals with intragastric absolute ethanol (1ml/30min. or 2ml/60min.) and hydrogen peroxide. The gastric mucosa morphological conditions were assessed "in vivo", concerning lesion area, pH and mucus. Ethanol (1ml/30min.) was observed to cause hyperemia, cell damage, rupture, edema, erosions, necrosis in gastric mucosa and significant increase in acid secretion. Absolute ethanol (2ml/60min.) caused a decrease in acid secretion due to alcalinization and an increase of mucus and pH. Intragastric hydrogem peroxide provoked gastric unwrinkling and hyperemia, acid secretions were not increased,...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Gastric acid secretion; Mucus; Ethanol; Hydrogen peroxide; Frog.
Ano: 1998
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1516-89131998000100007

Effects of hydrogen peroxide mouthwash on preventing ventilator-associated pneumonia in patients admitted to the intensive care unit
Provedor de dados: 55
Autores: Nobahar,Monir; Razavi,Mohammad Reza; Malek,Farhad; Ghorbani,Raheb.
Abstract  Aims The aim of the study was to determine the effect of hydrogen peroxide (HP) mouthwash on the incidence of ventilator associated pneumonia (VAP) in patients admitted to the intensive care unit (ICU).  Methods This was a randomized clinical trial conducted on 68 patients. The intervention group used 3% HP as mouthwash and the control group used mouthwashes with 0.9% normal saline (NS) twice a day. Data were collected using a questionnaire and the Modified Clinical Pulmonary Infection Score (MCPIS). MCPIS includes five items, body temperature: white blood cell count, pulmonary secretions, the ratio of pressure of arterial oxygen (PaO2) to fraction of inspired oxygen (FiO2), and the chest X-ray. Each of these items scored 0–2. Scores ≥6 were...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Nosocomial infection; Ventilator associated pneumonia; Hydrogen peroxide; Intensive care unit.
Ano: 2016
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1413-86702016000500444

Age-related changes and effects of regular low-intensity exercise on gait, balance, and oxidative biomarkers in the spinal cord of Wistar rats
Provedor de dados: 56
Autores: Silveira,E.M.S.; Kroth,A.; Santos,M.C.Q.; Silva,T.C.B.; Silveira,D.; Riffel,A.P.K.; Scheid,T.; Trapp,M.; Partata,W.A.
The present study aimed to analyze age-related changes to motor coordination, balance, spinal cord oxidative biomarkers in 3-, 6-, 18-, 24-, and 30-month-old rats. The effects of low-intensity exercise on these parameters were also analyzed in 6-, 18-, and 24-month-old rats. Body weight, blood glucose, total cholesterol, and high-density lipoprotein (HDL) cholesterol were assessed for all rats. The soleus muscle weight/body weight ratio was used to estimate skeletal muscle mass loss. Body weight increased until 24 months; only 30-month-old rats exhibited decreased blood glucose and increased total cholesterol and HDL cholesterol. The soleus muscle weight/body weight ratio increased until 18 months, followed by a small decrease in old rats. Exercise did not...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Superoxide anion generation; Hydrogen peroxide; Total thiol content; Lipid hydroperoxide levels; Total antioxidant capacity; Superoxide dismutase.
Ano: 2019
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-879X2019000700608

Therapeutic concentration of morphine reduces oxidative stress in glioma cell line
Provedor de dados: 56
Autores: Almeida,M.B.; Costa-Malaquias,A.; Nascimento,J.L.M.; Oliveira,K.R.; Herculano,A.M.; Crespo-López,M.E.
Morphine is a potent analgesic opioid used extensively for pain treatment. During the last decade, global consumption grew more than 4-fold. However, molecular mechanisms elicited by morphine are not totally understood. Thus, a growing literature indicates that there are additional actions to the analgesic effect. Previous studies about morphine and oxidative stress are controversial and used concentrations outside the range of clinical practice. Therefore, in this study, we hypothesized that a therapeutic concentration of morphine (1 μM) would show a protective effect in a traditional model of oxidative stress. We exposed the C6 glioma cell line to hydrogen peroxide (H2O2) and/or morphine for 24 h and evaluated cell viability, lipid peroxidation, and...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Morphine; Glia; Oxidative stress; Hydrogen peroxide; Lipid peroxidation; Opiod.
Ano: 2014
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-879X2014000500398

Identification and in vitro production of Lactobacillus antagonists from women with or without bacterial vaginosis
Provedor de dados: 56
Autores: Branco,K.M.G.R.; Nardi,R.M.D.; Moreira,J.L.S.; Nunes,A.C.; Farias,L.M.; Nicoli,J.R.; Carvalho,M.A.R.
Lactobacilli isolated from the vaginal tract of women with and without bacterial vaginosis (BV) were identified and characterized for the production of antagonists. Bacterial samples were isolated from healthy women (N = 16), from patients with clinical complaints but without BV (N = 30), and from patients with BV (N = 32). Identification was performed using amplified ribosomal DNA restriction analysis. Production of antagonistic compounds was evaluated by the double-layer diffusion technique using Gram-positive (N = 9) and Gram-negative bacteria (N = 6) as well as yeast (N = 5) as indicator strains. Of a total of 147 isolates, 133 were identified as pertaining to the genus Lactobacillus. Lactobacillus crispatus was the species most frequently recovered,...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Lactobacillus; Bacterial vaginosis; Antagonism; Hydrogen peroxide; Identification.
Ano: 2010
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-879X2010000400003

Cytotoxicity of chlorhexidine digluconate to murine macrophages and its effect on hydrogen peroxide and nitric oxide induction
Provedor de dados: 56
Autores: Bonacorsi,C.; Raddi,M.S.G.; Carlos,I.Z.
Chlorhexidine, even at low concentrations, is toxic for a variety of eukaryotic cells; however, its effects on host immune cells are not well known. We evaluated in vitro chlorhexidine-induced cytotoxicity and its effects on reactive oxygen/nitrogen intermediate induction by murine peritoneal macrophages. Thioglycollate-induced cells were obtained from Swiss mice by peritoneal lavage with 5 ml of 10 mM phosphate-buffered saline, washed twice and resuspended (10(6) cells/ml) in appropriate medium for each test. Cell preparations contained more than 95% macrophages. The cytotoxicity was determined by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-tetrazolium bromide assay and the presence of hydrogen peroxide (H2O2) and nitric oxide (NO) by the horseradish...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Chlorhexidine; Cytotoxicity; Macrophages; Nitric oxide; Hydrogen peroxide.
Ano: 2004
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-879X2004000200007

Treatment with ascorbic acid and α-tocopherol modulates oxidative-stress markers in the spinal cord of rats with neuropathic pain
Provedor de dados: 56
Autores: Riffel,A.P.K.; Santos,M.C.Q.; de Souza,J.A.; Scheid,T.; Horst,A.; Kolberg,C.; Belló-Klein,A.; Partata,W.A.
Vitamin E (vit. E) and vitamin C (vit. C) are antioxidants that inhibit nociception. The effect of these vitamins on oxidative-stress markers in the spinal cord of rats with chronic constriction injury (CCI) of the sciatic nerve is unknown. This study investigated the effect of intraperitoneal administration of vit. E (15 mg·kg-1·day-1) and vit. C (30 mg·kg-1·day-1), given alone or in combination, on spinal cord oxidative-stress markers in CCI rats. Adult male Wistar rats weighing 200–250 g were divided equally into the following groups: Naive (rats did not undergo surgical manipulation); Sham (rats in which all surgical procedures involved in CCI were used except the ligature), and CCI (rats in which four ligatures were tied loosely around the right...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Total thiol; Superoxide anion generation; Nitric oxide; Lipid hydroperoxides; Hydrogen peroxide; Total antioxidant capacity.
Ano: 2018
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-879X2018000400612

Gastrodin induced HO-1 and Nrf2 up-regulation to alleviate H2O2-induced oxidative stress in mouse liver sinusoidal endothelial cells through p38 MAPK phosphorylation
Provedor de dados: 56
Autores: Zhang,Hongbin; Yuan,Bo; Huang,Hanfei; Qu,Siming; Yang,Shikun; Zeng,Zhong.
Nuclear factor erythroid-related factor 2 (Nrf2) has been implicated in several detoxifying and antioxidant defense processes. Nrf2-mediated heme oxygenase-1 (HO-1) expression was demonstrated to play a key role against oxidative stress. Gastrodin (GSTD) is a well-known active compound isolated from the roots of Rhizoma gastrodiae, a plant used in ancient Chinese traditional medicine. The aim of this work was to investigate whether GSTD could alleviate H2O2-induced oxidative stress in mouse liver sinusoidal endothelial cells (LSECs). In LSECs exposed to 1 mM H2O2, treatment with GSTD (1, 10, or 50 µM) resulted in higher cell viability than the untreated control. Treated cells maintained a higher Bcl2/Bax ratio and suppressed caspase-9 expression compared...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Gastrodin; Liver sinusoidal endothelial cells; Heme oxygenase 1; Oxidative stress; Hydrogen peroxide.
Ano: 2018
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-879X2018001000611

Glutathione peroxidase induction protects Saccharomyces cerevisiae sod1deltasod2delta double mutants against oxidative damage
Provedor de dados: 56
Autores: Manfredini,V.; Roehrs,R.; Peralba,M.C.R.; Henriques,J.A.P.; Saffi,J.; Ramos,A.L.L.P.; Benfato,M.S.
Saccharomyces cerevisiae mutants deficient in superoxide dismutase genes (sod1delta, sod2delta and the double mutant) were subjected to H2O2 stress in the stationary phase. The highest sensitivity was observed in the sod2delta mutant, while the sod1deltasod2delta double mutant was not sensitive. Sod mutants had lower catalase activity (44%) than wild-type cells, independent of H2O2 stress. Untreated cells of sod1deltasod2delta double mutants showed increased glutathione peroxidase activity (126%), while sod1delta had lower activity (77%) than the wild type. Glutathione levels in sod1delta were increased (200-260%) after exposure to various H2O2 concentrations. In addition, the highest malondialdehyde levels could be observed without H2O2 treatment in...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Catalase; Superoxide dismutase; Glutathione; Hydrogen peroxide; Saccharomyces cerevisiae; Reactive oxygen species.
Ano: 2004
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-879X2004000200001

A method for multiple sequential analyses of macrophage functions using a small single cell sample
Provedor de dados: 56
Autores: Nascimento,F.R.F.; Rodríguez,D.; Gomes,E.; Fernvik,E.C.; Russo,M.
Microbial pathogens such as bacillus Calmette-Guérin (BCG) induce the activation of macrophages. Activated macrophages can be characterized by the increased production of reactive oxygen and nitrogen metabolites, generated via NADPH oxidase and inducible nitric oxide synthase, respectively, and by the increased expression of major histocompatibility complex class II molecules (MHC II). Multiple microassays have been developed to measure these parameters. Usually each assay requires 2-5 x 10(5) cells per well. In some experimental conditions the number of cells is the limiting factor for the phenotypic characterization of macrophages. Here we describe a method whereby this limitation can be circumvented. Using a single 96-well microassay and a very small...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Macrophages; Nitric oxide; Hydrogen peroxide; MHC II; Method.
Ano: 2003
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-879X2003000900012

Involvement of Src tyrosine kinase and protein kinase C in the expression of macrophage migration inhibitory factor induced by H2O2 in HL-1 mouse cardiac muscle cells
Provedor de dados: 56
Autores: Rao,F.; Deng,C.Y.; Zhang,Q.H.; Xue,Y.M.; Xiao,D.Z.; Kuang,S.J.; Lin,Q.X.; Shan,Z.X.; Liu,X.Y.; Zhu,J.N.; Yu,X.Y.; Wu,S.L.
Macrophage migration inhibitory factor (MIF), a pleiotropic cytokine, plays an important role in the pathogenesis of atrial fibrillation; however, the upstream regulation of MIF in atrial myocytes remains unclear. In the present study, we investigated whether and how MIF is regulated in response to the renin-angiotensin system and oxidative stress in atrium myocytes (HL-1 cells). MIF protein and mRNA levels in HL-1 cells were assayed using immunofluorescence, real-time PCR, and Western blot. The result indicated that MIF was expressed in the cytoplasm of HL-1 cells. Hydrogen peroxide (H2O2), but not angiotensin II, stimulated MIF expression in HL-1 cells. H2O2-induced MIF protein and gene levels increased in a dose-dependent manner and were completely...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Macrophage migration inhibitory factor; HL-1 cells; Hydrogen peroxide; Atrial fibrillation; Protein kinases.
Ano: 2013
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-879X2013000900746

Effect of trolox C on cardiac contracture induced by hydrogen peroxide
Provedor de dados: 56
Autores: Belló-Klein,A.; Oliveira,A.R.; Miranda,M.F.S.; Irigoyen,M.C.; Homem-de-Bittencourt Jr.,P.I.; Llesuy,S.; Belló,A.A.
Hydrogen peroxide (H2O2) perfused into the aorta of the isolated rat heart induces a positive inotropic effect, with cardiac arrhythmia such as extrasystolic potentiation or cardiac contractures, depending on the dose. The last effect is similar to the "stone heart" observed in reperfusion injury and may be ascribed to lipoperoxidation (LPO) of the membrane lipids, to protein damage, to reduction of the ATP level, to enzymatic alterations and to cardioactive compounds liberated by LPO. These effects may result in calcium overload of the cardiac fibers and contracture ("stone heart"). Hearts from male Wistar rats (300-350 g) were perfused at 31oC with Tyrode, 0.2 mM trolox C, 256 mM H2O2 or trolox C + H2O2. Cardiac contractures (baseline elevation of the...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Trolox C; "stone heart"; Free radicals; Hydrogen peroxide.
Ano: 1997
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-879X1997001100013

Antioxidant responses of Laeonereis acuta (Polychaeta) after exposure to hydrogen peroxide
Provedor de dados: 56
Autores: Rosa,C.E. da; Bianchini,A.; Monserrat,J.M.
The effects of H2O2 were evaluated in the estuarine worm Laeonereis acuta (Polychaeta, Nereididae) collected at the Patos Lagoon estuary (Southern Brazil) and maintained in the laboratory under controlled salinity (10 psu diluted seawater) and temperature (20°C). The worms were exposed to H2O2 (10 and 50 µM) for 4, 7, and 10 days and the following variables were determined: oxygen consumption, catalase (CAT) and glutathione peroxidase activity in both the supernatant and pellet fractions of whole body homogenates. The concentrations of non-protein sulfhydryl and lipid peroxides (LPO) were also measured. The oxygen consumption response was biphasic, decreasing after 4 days and increasing after 7 and 10 days of exposure to 50 µM H2O2 (P &lt; 0.05). At the...
Tipo: Info:eu-repo/semantics/other
Palavras-chave: Worms; Laeonereis acuta; Hydrogen peroxide; Oxidative stress; Antioxidant enzymes; Oxygen consumption.
Ano: 2008
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-879X2008000200007

Cytotoxic activity of BCG-activated macrophages against L929 tumor cells is nitric oxide-dependent
Provedor de dados: 56
Autores: Nascimento,F.R.F.; Ribeiro-Dias,F.; Russo,M.
The tumoricidal activity of activated macrophages has been attributed largely to the release of tumor necrosis factor (TNF), or to the production of reactive oxygen or nitrogen intermediates. The L929 tumor cell line (a murine fibroblast-like cell) when treated with actinomycin D (ActD) has been used to measure TNF&lt;FONT FACE="Symbol"&gt;a&lt;/FONT&gt; cytotoxicity. In the present study, we determined the cytotoxic activity of BCG-activated peritoneal macrophages against ActD-untreated L929 tumor cells. Furthermore, we measured the production of hydrogen peroxide (H2O2), nitric oxide (NO) and TNF by macrophages cultured in the presence or absence of L929 cells. As expected, BCG-activated macrophages produced significant amounts of H2O2 (16.0 ± 3.0 µM),...
Tipo: Info:eu-repo/semantics/other
Palavras-chave: Cytotoxicity; Macrophages; L929 tumor cells; Nitric oxide; TNF; Hydrogen peroxide.
Ano: 1998
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-879X1998001200012

Hydrogen peroxide induces a specific DNA base change profile in the presence of the iron chelator 2,2’ dipyridyl in Escherichia coli
Provedor de dados: 56
Autores: Felício,D.L.; Almeida,C.E.B.; Silva,A.B.; Leitão,A.C.
Pretreatment of Escherichia coli cultures with the iron chelator 2,2’-dipyridyl (1 mM) protects against the lethal effects of low concentrations of hydrogen peroxide (&lt;15 mM). However, at H2O2 concentrations equal to or greater than 15 mM, dipyridyl pretreatment increases lethality and mutagenesis, which is attributed to the formation of different types of DNA lesions. We show here that pretreatment with dipyridyl (1 mM) prior to challenge with high H2O2 concentrations (≥15 mM) induced mainly G:C→A:T transitions (more than 100X with 15 mM and more than 250X with 20 mM over the spontaneous mutagenesis rate) in E. coli. In contrast, high H2O2 concentrations in the absence of dipyridyl preferentially induced A:T→T:A transversions (more than 1800X and more...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Hydrogen peroxide; Dipyridyl; Mutagenesis; Iron; Fenton reaction.
Ano: 2009
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-879X2009001100003

Heterologous expression of a rice metallothionein isoform (OsMTI-1b) in Saccharomyces cerevisiae enhances cadmium, hydrogen peroxide and ethanol tolerance
Provedor de dados: 58
Autores: Ansarypour,Zahra; Shahpiri,Azar.
Abstract Metallothioneins are a superfamily of low-molecular-weight, cysteine (Cys)-rich proteins that are believed to play important roles in protection against metal toxicity and oxidative stress. The main purpose of this study was to investigate the effect of heterologous expression of a rice metallothionein isoform (OsMTI-1b) on the tolerance of Saccharomyces cerevisiae to Cd2+, H2O2 and ethanol stress. The gene encoding OsMTI-1b was cloned into p426GPD as a yeast expression vector. The new construct was transformed to competent cells of S. cerevisiae. After verification of heterologous expression of OsMTI-1b, the new strain and control were grown under stress conditions. In comparison to control strain, the transformed S. cerevisiae cells expressing...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Cadmium; Ethanol; Hydrogen peroxide; Rice metallothionein; S. cerevisiae.
Ano: 2017
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1517-83822017000300537

High levels of catalase in sod mutants of Saccharomyces cerevisiae in high aeration conditions
Provedor de dados: 58
Autores: Martins,Vanessa; Manfredini,Vanusa; Benfato,Mara Silveira.
Saccharomyces cerevisiae mutants deficient in superoxide dismutase genes (sod1delta, sod2delta and sod1deltasod2delta mutants) in a stationary phase of growth under high aeration conditions were subjected to H2O2 stress. All the mutants were sensitive after H2O2 treatment. Glutathione peroxidase levels were significantly lower in sod1delta and sod2delta single mutants than in the wild-type without treatment. After exposure to H2O2 concentrations, glutathione peroxidase levels were increased in sod1deltasod2delta double mutants and the sod2delta single mutant, while sod1delta maintained lower gluthatione peroxidase activities. The sod2delta mutant demonstrated a similar catalase activity to that of the wild-type without treatment, whilst decreased catalase...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Catalase; Superoxide dismutase; High aeration; Hydrogen peroxide; S. cerevisiae.
Ano: 2005
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1517-83822005000400008

Pretreatment with H2O2 in maize seeds: effects on germination and seedling acclimation to salt stress
Provedor de dados: 61
Autores: Gondim,Franklin A; Gomes-Filho,Enéas; Lacerda,Claudivan F; Prisco,José Tarquinio; Azevedo Neto,André D; Marques,Elton C.
The aim of this study was to evaluate the effects of H2O2 on germination and acclimation of maize plants subject to salt stress. Three experiments using BRS3003 seeds, a triple hybrid of maize, were carried out in a growth room and in greenhouse. In the first experiment, H2O2 accelerated the germination percentage of seeds at 100 mM, but not at 500 mM. In the second experiment, the pretreatment of seeds was observed to induce a pronounced increase in ascorbate peroxidase (APX) and catalase (CAT) enzyme activity after 30 h of soaking in H2O2. It was also observed that guaiacol peroxidase (GPX) activity was smaller in the seeds soaked in H2O2 for 12, 24, 30, 36 and 42 h, in relation to those soaked in distilled water. The superoxide dismutase (SOD) activity...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Antioxidant enzymes; Hydrogen peroxide; Oxidative stress; Salinity stress; Zea mays.
Ano: 2010
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1677-04202010000200004

Preservatives and neutralizing substances in milk: analytical sensitivity of official specific and nonspecific tests, microbial inhibition effect, and residue persistence in milk
Provedor de dados: 65
Autores: Silva,Livia Cavaletti Corrêa da; Tamanini,Ronaldo; Pereira,Juliana Ramos; Rios,Edson Antônio; Ribeiro Junior,José Carlos; Beloti,Vanerli.
Milk fraud has been a recurring problem in Brazil; thus, it is important to know the effect of most frequently used preservatives and neutralizing substances as well as the detection capability of official tests. The objective of this study was to evaluate the analytical sensitivity of legislation-described tests and nonspecific microbial inhibition tests, and to investigate the effect of such substances on microbial growth inhibition and the persistence of detectable residues after 24/48h of refrigeration. Batches of raw milk, free from any contaminant, were divided into aliquots and mixed with different concentrations of formaldehyde, hydrogen peroxide, sodium hypochlorite, chlorine, chlorinated alkaline detergent, or sodium hydroxide. The analytical...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Fraud; Formaldehyde; Hydrogen peroxide; Chlorinated compounds; Inhibitors.
Ano: 2015
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0103-84782015000901613