Repositório Institucional - Unifesp :: Navegando por Palavras-chave "Free radicals"

Navegando por Palavras-chave "Free radicals"

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Acesso aberto (Open Access)
1,4-Diamino-2-butanone, a wide-spectrum microbicide, yields reactive species by metal-catalyzed oxidation
(Elsevier B.V., 2011-06-15) Soares, Chrislaine Oliveira; Alves, Maria Julia Manso; Bechara, Etelvino José Henriques [UNIFESP]; Universidade de São Paulo (USP); Universidade Federal de São Paulo (UNIFESP)
The alpha-aminoketone 1,4-diamino-2-butanone (DAB), a putrescine analogue, is highly toxic to various microorganisms, including Trypanosoma cruzi. However, little is known about the molecular mechanisms underlying DAB's cytotoxic properties. We report here that DAB (pK(a) 7.5 and 9.5) undergoes aerobic oxidation in phosphate buffer, pH 7.4, at 37 degrees C, catalyzed by Fe(II) and Cu(II) ions yielding NH(4)(+) ion, H(2)O(2), and 4-amino-2-oxobutanal (oxoDAB). OxoDAB, like methylglyoxal and other alpha-oxoaldehydes, is expected to cause protein aggregation and nucleobase lesions. Propagation of DAB oxidation by superoxide radical was confirmed by the inhibitory effect of added SOD (50 U ml(-1)) and stimulatory effect of xanthine/xanthine oxidase, a source of superoxide radical. EPR spin trapping studies with 5,5-dimethyl-1-pyrroline-1-oxide (DMPO) revealed an adduct attributable to DMPO-HO(center dot), and those with alpha-(4-pyridyl-1-oxide)-N-tert-butylnitrone or 3,5-dibromo-4-nitrosobenzenesulfonic acid, a six-line adduct assignable to a DAB(center dot) resonant enoyl radical adduct. Added horse spleen ferritin (HoSF) and bovine apo-transferrin underwent oxidative changes in tryptophan residues in the presence of 1.0-10 mM DAB. Iron release from HoSF was observed as well. Assays performed with fluorescein-encapsulated liposomes of cardiolipin and phosphatidylcholine (20:80) incubated with DAB resulted in extensive lipid peroxidation and consequent vesicle permeabilization. DAB (0-10 mM) administration to cultured LLC-MK2 epithelial cells caused a decline in cell viability, which was inhibited by preaddition of either catalase (4.5 mu M) or aminoguanidine (25 mM). Our findings support the hypothesis that DAB toxicity to several pathogenic microorganisms previously described may involve not only reported inhibition of polyamine metabolism but also DAB pro-oxidant activity. (C) 2011 Elsevier Inc. All rights reserved.
Acesso aberto (Open Access)
17 beta-Estradiol and steady-state concentrations of H2O2: antiapoptotic effect in endometrial cells from patients with endometriosis
(Elsevier B.V., 2013-07-01) Andrade, Sheila Siqueira [UNIFESP]; Azevedo, Aline de Cássia [UNIFESP]; Monasterio, Izabel C. G. [UNIFESP]; Paredes-Gamero, Edgar Julian [UNIFESP]; Gonçalves, Giovana Aparecida [UNIFESP]; Bonetti, Tatiana Carvalho de Souza [UNIFESP]; Albertoni, Guilherme Ambrozio [UNIFESP]; Schor, Eduardo [UNIFESP]; Barreto, Jose A.; Oliva, Maria Luiza Vilela [UNIFESP]; Juliano, Luiz [UNIFESP]; Girão, Manoel João Batista Castello [UNIFESP]; Silva, Ismael Dale Cotrim Guerreiro da [UNIFESP]; Universidade Federal de São Paulo (UNIFESP); Charitable Assoc Blood Collect
Increased levels of hydrogen peroxide (H2O2) can initiate protective responses to limit or repair oxidative damage. However, H2O2 signals also fine-tune responses to growth factors and cytokines controlling cell division, differentiation, and proliferation. Because 17 beta-estradiol (E-2) also plays important roles in these processes, and is considered a major risk factor in the development and progression of endometriosis, this study evaluated whether E-2 has an antiapoptotic effect on oxidative stress in endometrial cells in combination with steady-state H2O2 levels ([H2O2]ss). Endometrial stromal cells were prepared from the eutopic endometrium of 18 women with and without endometriosis to produce primary cells. These cells were stimulated with E-2 for 20 h, exposed to [H2O2]ss, and examined for cell viability, proliferation, and apoptosis. the endometrial cells from women with endometriosis maintained the steady state for 120 min at high H2O2 concentrations. When they were pretreated with E-2 and exposed to [H2O2]ss, a decrease in apoptosis level was observed compared to the control cells (p < 0.01). the endometrial cells from patients with endometriosis subjected to both E-2 and [H2O2]ss showed increased ERK phosphorylation. These findings suggested that H2O2 is a signaling molecule that downregulates apoptosis in endometrial cells, supporting the fact that endometriosis, albeit a benign disease, shares some features with cancer such as decreased catalase levels. These results link the E-2 effects on [H2O2]ss to resistance to apoptosis and progression of endometriosis. (C) 2013 Elsevier Inc. All rights reserved.
Somente Metadadados
Arginase 2 and nitric oxide synthase: Pathways associated with the pathogenesis of thyroid tumors
(Elsevier B.V., 2010-09-15) Sousa, Maria Sharmila A. [UNIFESP]; Latini, Flavia R. M. [UNIFESP]; Monteiro, Hugo P. [UNIFESP]; Cerutti, Janete M. [UNIFESP]; Universidade Federal de São Paulo (UNIFESP)
We have previously shown that ARG2 expression was increased in most malignant thyroid tumors, but absent in benign lesions and normal tissues. Small interfering RNA knockdown was used to investigate the role of ARG2 in a thyroid carcinoma cell line. ARG2 knockdown decreased eNOS expression as well as the expression of eNOS-related genes (p21, Akt1, HIF-1, VEGF, and CAVI). ARG2 silencing changed tumor properties of thyroid cancer cells promoting apoptosis and reduced expression of cell proliferation markers. These results, coupled with enhanced nitric oxide production and elevated reactive oxygen species (ROS) levels, account for the altered intracellular redox environment. Genes related to either production (DUOX1 and NOX4) or catabolism (SODS) of ROS and reactive nitrogen species were negatively modulated by ARG2 knockdown. Additionally, a positive correlation of ARG2 with eNOS and related genes was investigated in thyroid tumors, further substantiating our in vitro findings. Our results suggest that ARG2 and eNOS may work in a coordinated manner and the underlying mechanism might be of major significance for thyroid tumorigenesis and/or tumor progression pathways. Fine modulation of ARG2, eNOS, and related genes may represent a potential source for targeted therapy of several cancer types. (C) 2010 Elsevier Inc. All rights reserved.
Acesso aberto (Open Access)
“A associação entre hormônios sexuais femininos e o processo de estresse oxidativo e inflamatório no desenvolvimento de doenças cardiovasculares em mulheres obesas: uma revisão literária”
(Universidade Federal de São Paulo, 2022-02-14) Fernandes, Mayla Franciele Lopes [UNIFESP]; Oliveira, Jean Carlo Siqueira de [UNIFESP]; Lambertucci, Rafael Herling [UNIFESP]; http://lattes.cnpq.br/5826005580515987; http://lattes.cnpq.br/0985561086549125; Universidade Federal de São Paulo (UNIFESP)
A obesidade é considerada uma doença crônica e multifatorial, caracterizada por acúmulo excessivo de gordura corporal de forma regional ou global, e seu desenvolvimento envolve fatores comportamentais, ambientais, genéticos e hormonais. A adiposidade está relacionada ao aumento de mediadores inflamatórios como elevação da proteína C-reativa e também aumento do estresse oxidativo, principalmente pela produção de espécies reativas de oxigênio (ERO) e diminuição de substâncias antioxidantes, ocasionando danos celulares, estes fatores associados alteram as funções endócrinas ocasionando a redução dos níveis de estrogênio, e elevando o risco de doenças cardiovasculares, considerando que o estradiol exerce papel protetor sobre o sistema cardíaco. O objetivo do estudo foi avaliar na literatura a associação entre hormônios sexuais femininos, o processo de estresse oxidativo e a inflamação no desenvolvimento de doenças cardiovasculares em mulheres obesas. Utilizou-se a base de dados MEDLINE, obtendo-se inicialmente 23 resultados, sendo que apenas 9 atenderam aos critérios de elegibilidade estabelecidos. Os estudos avaliados demonstram que existe relação direta entre mulheres obesas com o sistema antioxidante e hormonal, indicando um aumento do processo inflamatório, formação de EROs, atividade de enzimas antioxidantes aumentada e maior agregação plaquetária concomitante com a diminuição de fatores anti-inflamatórios como a adiponectina e a glutationa. Além disso, a resistência insulina, como demonstrado nos estudos, é um elemento importante no processo correlacionado a biomarcadores de estresse oxidativo, sendo componente central das doenças da síndrome metabólica como, por exemplo, a Síndrome dos Ovários Policísticos. Todavia, é necessária a realização de mais estudos para avaliar essas relações encontradas, como, até que ponto essas pode contribuir para o desenvolvimento de doenças cardiovasculares, qual o nível de relevância na prática clínica, se há possibilidade de manejar os fatores potencializadores dessa situação e refletir sobre planejamentos terapêuticos que considerem essas relações.
Acesso aberto (Open Access)
Baccharis dracunculifolia, the main source of green propolis, exhibits potent antioxidant activity and prevents oxidative mitochondrial damage
(Elsevier B.V., 2012-03-01) Guimaraes, Natalia S. S.; Mello, Joyce C.; Paiva, Juliana S.; Bueno, Paula C. P.; Berretta, Andresa A.; Torquato, Ricardo José Soares [UNIFESP]; Nantes, Iseli L.; Rodrigues, Tiago; Univ Mogi das Cruzes UMC; Univ Estadual Paulista UNESP; Universidade de São Paulo (USP); Universidade Federal de São Paulo (UNIFESP); Universidade Federal do ABC (UFABC)
Baccharis dracunculifolia DC (Asteraceae) is the main botanical source used by honeybees to produce Brazilian green propolis whose hepatoprotective properties have been already described. in this work we investigated the protective effects of the glycolic extract of B. dracunculifolia (GEBd) against oxidative stress in isolated rat liver mitochondria (RLM). the GEBd was prepared by fractionated percolation using propylene glycol as solvent. the total phenols and flavonoids, which are substances with recognized antioxidant action, were quantified in GEBd and the phytochemical analysis was carried out by HPLC. GEBd exhibited significant scavenger activity towards DPPH radicals and superoxide anions in a concentration-dependent manner, and also a Fe2+ chelating activity. GEBd decreased the basal H2O2 generation and the Fe2+- or t-BuOOH-induced ROS production in isolated mitochondria. Lipid oxidation of mitochondrial membranes, protein thiol groups and GSH oxidation were also prevented by GEBd. This shows that B. dracunculifolia exhibit potent antioxidant activity protecting liver mitochondria against oxidative damage and such action probably contribute to the antioxidant and hepatoprotective effects of green propolis. (C) 2011 Elsevier B.V. All rights reserved.
Acesso aberto (Open Access)
Comportamento do estresse oxidativo e da capacidade antioxidante total em ratos submetidos a retalhos cutâneos isquêmicos
(Sociedade Brasileira para o Desenvolvimento da Pesquisa em Cirurgia, 2004-01-01) Cymrot, Moacir [UNIFESP]; Percário, Sandro [UNIFESP]; Ferreira, Lydia Masako [UNIFESP]; Universidade Federal de São Paulo (UNIFESP)
PURPOSE: to study oxidative stress (MDA) and total antioxidant status (CAT) in fragments of randomic ischemic skin flaps from rat dorsum. METHODS: 18 male rats, young adults (Wistar EPM-1, 290 - 350g), that underwent elevation of randomic ischemic flaps from dorsum, were divided in three groups (N=6), according to post-operative time-points: immediate (POI), third and seventh post-operative days (PO3 and PO7), respectively. At the end, peripheral blood samples and tissue fragments of the flap and of normal skin outside flap were draw for MDA and CAT measurement. RESULTS: serum MDA values in group POI were significantly lower than those in PO3 and PO7, both latter in the same range. No differences were found among MDA values of the skin samples in any of the three groups. The analysis of the total antioxidant status of the animal s serum (CAT) did not show significant differences among the three groups. However, in the skin flap samples, the CAT values significantly decreased with time. CONCLUSION: The lack of significant differences among MDA values in skin samples from all groups, and the decreasing CAT values with time, suggest that the existence of necrosis at the distal portion of flaps in group PO7 is due not only to oxidant aggression but mainly to the reduction of local antioxidant status.
Acesso aberto (Open Access)
Conceitos atuais e perspectivas na prevenção da degeneração macular relacionada à idade
(Sociedade Brasileira de Oftalmologia, 2008-06-01) Torres, Rogil José De Almeida [UNIFESP]; Précoma, Dalton Bertolim; Maia, Maurício [UNIFESP]; Kaiber, Flávia; Prim, Camila; Luchini, Andréa; Matos, Rossane Serafin; Farah, Michel Eid [UNIFESP]; Universidade Federal de São Paulo (UNIFESP); Hospital Angelina Caron; Pontifícia Universidade Católica do Paraná Departamento de Cardiologia; Hospital de Olhos Oeste Paulista Serviço de Cirurgia Vitreorretiniana; Pontifícia Universidade Católica do Paraná; Nutrimedical Curitiba; Centro Oftalmológico de Curitiba
The authors prepare a literature review about the main antioxidants used in daily practice for the prevention of age-related macular degeneration progression (AMD), emphasizing the mechanism of action of each substance as well as the possible complications related to the overuse of such components.
Somente Metadadados
Efeito do dimetil sulfóxido sobre a necrose dos retalhos cutâneos, em ratos
(Universidade Federal de São Paulo (UNIFESP), 1996) Duarte, Ivone da Silva [UNIFESP]; Ferreira, Lydia Masako [UNIFESP]; Universidade Federal de São Paulo (UNIFESP)
Acesso aberto (Open Access)
Efeito do peróxido de hidrogênio (H2O2) no íleo
(Universidade Federal de São Paulo (UNIFESP), 2017-07-31) Cesário, Thalyta Aparecida Munhóz [UNIFESP]; Smith, Ricardo Luiz [UNIFESP]; http://lattes.cnpq.br/2039545891941644; http://lattes.cnpq.br/1091529937004985; Universidade Federal de São Paulo (UNIFESP)
The study of reactive oxygen species becomes interesting due to production by normal cellular metabolism, in the presence of diseases and the ability to oxidize biological macromolecules. H2O2 included in the ROS class is often studied, but the effects are quite variable depending on the tissue, organ and the animal species studied. In general, H2O2 has a dual effect on biological systems, depending on concentration range, acting deleteriously at high concentrations (range of μM to mM) or as a cell marker at lower concentrations (nM range). Thus, the objective of this study was to investigate the effect of exogenous H2O2 administration in ileum isolated from mice to evaluate possible changes in morphology, redox state and antioxidant defense to further deepen the understanding of the effects of induced oxidative stress in ileum. The following results were observed: the exogenous administration of H2O2 for 20 minutes promoted changes depending on the concentration: at 100 nM concentration, was observed an increase in the thickness of the longitudinal and circular layer, with a moderate alteration of the intestinal mucosa, but an increase in lipid peroxidation. At concentrations of 100 μM and 1 mM were observed total villus destruction of the intestinal mucosa and reduction of the muscular layer. In relation to the redox state, there was a decrease in the activity of the antioxidant enzyme catalase (CAT), but of activation of the enzyme superoxide dismutase (SOD) and maintenance of levels of lipid peroxidation at concentrations of 100 μM and 1 mM. These data are indicative of the similarity of mouse ileum results as described in other animal species, that is, ileum is extremely sensitive to exogenous H2O2 administration and this compound acts positively or negatively on the structural and functional integrity of the organ.
Acesso aberto (Open Access)
O efeito do tratamento com carnosina durante o processamento seminal de amotras humanas por gradiente de densidade descontínuo
(Universidade Federal de São Paulo (UNIFESP), 2018-02-27) Adami, Luana Nayara Gallego [UNIFESP]; Nichi, Marcilio; http://lattes.cnpq.br/7054360633543023; Universidade Federal de São Paulo (UNIFESP)
Introdução: A infertilidade masculina pode ser causada pelo estresse oxidativo seminal que leva prejuízos aos espermatozoides. Entretanto, o plasma seminal possui mecanismos antioxidantes para tentar neutralizar esses danos celulares. Por outro lado, as biotécnicas utilizadas durante o processamento seminal tendem a diminuir essa proteção antioxidante aumentando os danos oxidativos ao gameta. Na tentativa de minimizar os danos, antioxidantes exógenos são suplementados nos sistemas in vitro. A carnosina, reportada por sua potente função antioxidante, tem capacidade de reagir com produtos responsáveis por provocar danos celulares. Dessa forma suplementar carnosina nos meios de processamento seminal levaria a uma melhora na qualidade funcional dos espermatozoides. Objetivo: Avaliar o efeito de diferentes concentrações da carnosina no processamento das amostras seminais. Método: As amostras seminais (n=34) foram divididas em 3 grupos e seguiram para o processamento seminal: grupo controle sem suplementação com a carnosina (0) recebeu as camadas de gradiente de densidade descontínua – Percoll (80% e 40%) e a amostra; o grupo 20 mM, por sua vez, teve as camadas de Percoll suplementadas com 20 mM de carnosina; finalmente, o grupo 50mM teve as camadas de Percoll suplementadas com 50 mM de carnosina. As amostras passaram pelo processo de gradiente de densidade descontínuo por 20 minutos a 600xG e foram lavadas com meio de cultura fluido tubário humano (HTF) por 10 minutos a 600xG. Após o processamento, os espermatozoides foram avaliados quanto ao potencial de membrana mitocondrial, à produção de ânion superóxido intracelular, à fragmentação de DNA espermático, à integridade acrossômica, à atividade mitocondrial, à integridade de membrana plasmática e à motilidade espermática. Para analisar a normalidade e esfericidade dos dados, utilizamos os testes de Kolmogorov-Smirnov e de Mauchly respectivamente, e então o General Linear Model (GLM) com teste post-hoc de Sidak. Para as variáveis não normais foi utilizado o teste não paramétrico de Friedman com post-hoc de Games-Howell, considerando α = 5% e utilizando o programa SPSS21. Resultados: A suplementação com a carnosina na concentração de 50 mM levou à melhora da atividade mitocondrial dos espermatozoides quando comparado ao grupo controle. Para variáveis como % de espermatozoides móveis e % de espermatozoides progressivos, velocidade média de percurso, retilínea e curvilínea, e linearidade dos espermatozoides houve uma melhora nos índices após o gradiente de densidade descontínuo, entretanto as concentrações de carnosina não foram efetivas. Já para a frequência de batimento dos flagelos a presença de carnosina em ambas concentrações elevou as frequências quando comparadas à amostra antes do gradiente de densidade descontínuo. Conclusão: A suplementação da carnosina nas amostras seminais humanas pode apresentar efeito benéfico para a atividade mitocondrial espermática e a frequência de batimento cruzado, amenizando os possíveis danos provocados pelo processamento seminal.
Acesso aberto (Open Access)
Effect of electroacupuncture to prevent selenite-induced cataract in Wistar rats
(Conselho Brasileiro de Oftalmologia, 2006-06-01) Cariello, Angelino Julio [UNIFESP]; Casanova, Fábio Henrique [UNIFESP]; Lima Filho, Acácio Alves de Souza [UNIFESP]; Juliano, Yara [UNIFESP]; Tabosa, Angela Maria Florencio [UNIFESP]; Universidade Federal de São Paulo (UNIFESP)
PURPOSE: To investigate whether electroacupuncture can prevent selenite-induced cataract in an experimental model. METHODS: Fifty Wistar rat pups were randomized into 5 groups of 10 animals: Group 1 (control), no procedure was performed; Group 2 (selenite), sodium selenite (30 micromoles/kg body weight) was injected subcutaneously between postpartum days 10 to 12; Group 3 (anesthesia) received the same dose of selenite and underwent ether inhalation anesthesia during 10 minutes daily for one week; Group 4 (electroacupuncture) underwent the same procedure of Group 3, but also receiving electroacupuncture (2 Hz, 50 mA) applied to the Neiguan (PC6) and Guangming (GB37) acupoints during the anesthesia period; and Group 5 (Sham) underwent the same procedures of Group 4, but needles were applied to non-acupoints. The development of cataract was assessed one week later, and its density was graded by slit lamp biomicroscopy. RESULTS: All control rats lenses (Group 1) were clear. Groups 2, 3 and 5 rats developed more severe cataract or complete opacification. In Group 4 (electroacupuncture), 45% of eyes did not develop cataract while thirty per cent developed less severe cataract than Groups 2, 3 and 5. The between-group difference was statistically significant (p<0.001). Lens opacification grade in Groups 1 and 4 was lower than in the Groups 2, 3 and 5 (p<0.001). CONCLUSION: Electroacupuncture effectively decreased selenite-induced cataract formation rate in pup rats when needles were applied at specific acupoints.
Somente Metadadados
Effect of transgastric peritoneal access on peritoneal innate cellular immunity: experimental study in swine
(Springer, 2013-03-01) Rodrigues, Rodrigo [UNIFESP]; Rezende, Marcelo [UNIFESP]; Gomes, Gustavo [UNIFESP]; Souza, Fernando; Blagitz, Maiara; Della Libera, Alice; Taha, Murched [UNIFESP]; Ferrari, Angelo Paulo [UNIFESP]; Della Libera, Ermelindo [UNIFESP]; Universidade Federal de São Paulo (UNIFESP); Fleury Med & Saude; Hosp Israelita Albert Einstein
One of the main concerns of natural orifice surgery is the local and systemic impact on physiology. Few studies have compared natural orifice transluminal endoscopic surgery (NOTES) with other surgical modalities. Most studies are based on systemic variables such as postoperative serum cytokines, with conflicting results. Surgical trauma induces an early inflammatory response, release of cytokines, and local leukocyte activation and oxidative burst. Major surgical trauma is related to impairment of phagocytic function and an increase in production of active oxygen species by phagocytes. the aim of this study was to evaluate the impact of transgastric peritoneoscopy on peritoneal innate immune response compared with laparoscopy and laparotomy in swine.Thirty-four male Sus scrofa domesticus swine were assigned to four groups: transgastric peritoneoscopy (13), laparoscopy (7), laparotomy (7), and sham procedure (7). Twenty-four hours after the procedure, peritoneal fluid cells were harvested by peritoneal washing after necropsy. Flow cytometry analysis of labeled S. aureus and E. coli phagocytosis by peritoneal neutrophils and macrophages was blindly performed. Oxidative burst activity measured by H2O2 production under different challenges was also evaluated.Total operative time varied between all groups. the transgastric, laparoscopy, and laparotomy groups required 56, 17.2, and 40.3 min of mean operative time, respectively (p < 0.05). Even though the mean percentage and intensity of phagocytosis by peritoneal phagocytes were higher in the sham, transgastric, and laparoscopy groups, there was no significant difference between these groups and laparotomy. Macrophage production of H2O2 has been shown to be similar among the transgastric, laparoscopy, and sham groups, and smaller than that in laparotomy (p < 0.05), either under basal conditions, while performing E. coli phagocytosis, or challenged by the presence of E. coli membrane lipopolysaccharide.Under the conditions of this study, transgastric peritoneoscopy has been shown to have minimal impact on peritoneal innate immune response.
Acesso aberto (Open Access)
Endothelial nitric oxide synthase uncoupling as a key mediator of melanocyte malignant transformation associated with sustained stress conditions
(Elsevier B.V., 2011-05-15) Melo, Fabiana Henriques Machado de [UNIFESP]; Molognoni, Fernanda [UNIFESP]; Morais, Alice Santana [UNIFESP]; Toricelli, Mariana [UNIFESP]; Mouro, Margaret Gori [UNIFESP]; Higa, Elisa Mieko Suemitsu [UNIFESP]; Lopes, Jose Daniel [UNIFESP]; Jasiulionis, Miriam Galvonas [UNIFESP]; Universidade Federal de São Paulo (UNIFESP)
Melanoma cell lines and cells corresponding to premalignant melanocytes were established by our group after subjecting a nontumorigenic murine melanocyte lineage, melan-a, to sequential cycles of anchorage blockade. Previous results showed that in melan-a cells the superoxide level increases after such procedure. Superoxide production during melanocyte de-adhesion was inhibited by L-sepiapterin, the precursor of eNOS cofactor BH(4), and increased by the inhibitor of BH(4) synthesis, DAHP, hence indicating a partial uncoupling state of eNOS. the eNOS uncoupling seems to be maintained in cells derived from melan-a, because they present decreased nitric oxide and increased superoxide levels. the inhibition of superoxide production in Tm5 melanoma cells with L-sepiapterin reinforces their eNOS-uncoupled state. the maintenance of oxidative stress seems to be important in melanoma apoptosis resistance because Mn(III)TBAP, a superoxide scavenger, or L-sepiapterin renders Tm5 cells more sensitive to anoikis and chemotherapy. More importantly, eNOS uncoupling seems to play a pivotal role in melanocyte malignant transformation induced by sustained anchorage impediment, because no malignant transformation was observed when L-NAME-treated melanocytes were subjected to sequential cycles of de-adhesion. Our results show that uncoupled eNOS contributes to superoxide production during melanocyte anchorage impediment, contributing to anoikis resistance and malignant transformation. (C) 2011 Elsevier Inc. All rights reserved.
Acesso aberto (Open Access)
Estudo das alterações oxidativas, da capacidade antioxidante total e do óxido nítrico, em ratos submetidos à isquemia e reperfusão de membros posteriores
(Sociedade Brasileira para o Desenvolvimento da Pesquisa em Cirurgia, 2005-04-01) Francisco Neto, Acacio [UNIFESP]; Baptista-Silva, José Carlos Costa [UNIFESP]; Fagundes, Djalma José [UNIFESP]; Percário, Sandro; Novo, Neil Ferreira [UNIFESP]; Juliano, Yara [UNIFESP]; Moreira Neto, Antonio Augusto; Universidade Federal de São Paulo (UNIFESP); Universidade de Sorocaba; Santa Casa de Mogi das Cruzes
PURPOSE: To verify the effect of the ischemia time on the oxidative alterations, total antioxidant status and the nitric oxide, in the muscle, kidney and plasma, in rats submitted to ischemia and reperfusion of hind limbs. METHODS: Forty male rats were randomized in four groups with ten animals each. Laparotomy, abdominal aorta infra e juxta renal isolation. Groups 1 and 3 (sham), passage of the polipropilen 7.0 monofilamentary thread aorta around without bending it and waiting time of 1 hour to group 1 and 6 hours to group 3. Withdrawal of the thread, waiting time of 15 minutes, euthanasia and material collection. Groups 2 and 4 (experiments), ligation of abdominal aorta with the same thread and ischemia of 1 hour in the group 2 and 6 hours to the group 4. Withdrawal of the thread and reperfusion for 15 minutes. Euthanasia and blood collection by flowing; withdrawal of the left hind limb muscle and of the left kidney. The parameters evaluated were: malondialdehyde, total antioxidant status and the nitric oxide. RESULTS: The TStudent test and the MANN-WHITNEY test have been used as nonparametrics tests and the rejection level have been fixed in 0,05 or 5%. There were significative alterations of the malondialdehyde in the kidney. The total antioxidant status has been shoun significative alterations in the kidney, muscle and plasma. Although the nitric oxide has been altered in the plasma only. CONCLUSION: The ischemia time changing has provoked significative alterations of malondialdehyde, total antioxidant status and nitric oxide.
Acesso aberto (Open Access)
Estudo teórico dos estados eletrônicos e mecanismos fotodissociativos das moléculas SBr, SBr- e HSBr
(Universidade Federal de São Paulo, 2022-06-23) Ferreira, Jéssica Jaqueline [UNIFESP]; Hermoso, Willian [UNIFESP]; http://lattes.cnpq.br/4192903739260722
As preocupações ambientais relacionadas à destruição do ozônio na estratosfera estão focadas no aumento da velocidade da destruição da camada de ozônio por espécies químicas que atuam como catalisadores, potencializando tal reação, tais como compostos de nitrogênio, cloro, flúor, enxofre e bromo. Este trabalho teve como foco o estudo dos sistemas contendo enxofre, bromo e hidrogênio como espécies potencialmente importantes nos ciclos catalíticos da destruição do ozônio; na literatura há indícios que estas moléculas podem estar presentes na atmosfera terrestre, porém há poucos estudos que abordem o assunto e atuação delas na destruição da camada de ozônio. Como há poucos trabalhos publicados específicos sobre os sistemas diatômicos e triatômicos, este trabalho tem sua motivação em estudar as transições eletrônicas que tenham maior probabilidade de participar de mecanismos de dissociação das espécies moleculares HSBr, SBr e SBr - , e que possam apresentar o caminho de formação de radicais na atmosfera. Sendo assim, para a molécula SBr foi realizada a descrição eletrônica, a estimativa de seção de choque parcial, cálculo de coeficientes de tunelamento e foram estudadas as transições entre o estado fundamental dubleto de simetria para os estados excitados dubletos não ligados de representações de simetrias Σ + , Σ - e Δ, respectivamente; para a molécula triatômica, HSBr, foi realizada a descrição dos aspectos energéticos e estruturais, obtivemos as propriedades espectroscópicas assim como as curvas associadas com os cortes na superfície na dissociação e determinamos o espectro de fotodissociação desta molécula e, por fim, para o ânion diatômico SBr - obtivemos as curvas de energia potencial para os estados singletos mais baixos do estado de simetria espacial Σ + , Σ - Π e ∆, assim como um conjunto de constantes espectroscópicas dos estados ligados, uma descrição das funções de potencial e o perfil energético dos estados eletrônicos juntamente com os canais de dissociação.
Acesso aberto (Open Access)
Fatores modificáveis da degeneração macular relacionada à idade
(Conselho Brasileiro de Oftalmologia, 2009-06-01) Torres, Rogil José De Almeida [UNIFESP]; Maia, Maurício [UNIFESP]; Muccioli, Cristina [UNIFESP]; Winter, Guilherme; Souza, Greyce Kelly De; Pasqualotto, Luca Rodrigo; Luchini, Andréa; Précoma, Dalton Bertolim; Hospital Angelina Caron; Universidade Federal de São Paulo (UNIFESP); Hospital de Olhos Oeste Paulista Serviço de Cirurgia Vitreorretiniana; Pontifícia Universidade Católica do Paraná; PUCPR; Centro Oftalmológico de Curitiba; PUCPR Departamento de Cardiologia
The authors present the main modifiable risk factors that may trigger and/or worsen age-related macular degeneration. Mechanisms of action related to these factors as well as preventive measures and intervention effectiveness are discussed.
Acesso aberto (Open Access)
Increased exhalation of hydrogen peroxide in healthy subjects following cigarette consumption
(Associação Paulista de Medicina - APM, 2000-07-06) Guatura, Sandra Baltazar [UNIFESP]; Martinez, José Antônio Baddini [UNIFESP]; Bueno, Patricia Cincotto dos Santos [UNIFESP]; Santos, Manuel Lopes dos [UNIFESP]; Universidade Federal de São Paulo (UNIFESP); University of São Paulo Medical School of Ribeirão Preto Department of Medicine
CONTEXT: Increased hydrogen peroxide has been described in the expired breath condensate (H2O2-E) of several lung conditions, such as acute respiratory distress syndrome, chronic obstructive pulmonary disease and asthma. This technique has been advocated as being a simple method for documenting airway inflammation. OBJECTIVE: To evaluate H2O2-E in healthy cigarette smokers, and to determine the acute effects of the consumption of one cigarette on H2O2-E levels. TYPE OF STUDY: Prospective, controlled trial. SETTING: A pulmonary function laboratory in a University Hospital. PARTICIPANTS: Two groups of healthy volunteers: individuals who had never smoked (NS; n=10; 4 men; age = 30.6 ± 6.2 years) and current cigarette smokers (S; n=12; 7 men; age = 38.7 ± 9.8). None of the volunteers had respiratory symptoms and all showed normal spirometric tests. INTERVENTION: Expired air was collected from all volunteers through a face mask and a plastic collecting system leading into a flask with dry ice and pure ethanol. Samples from the group S were collected twice, before and half an hour after the combustion of one cigarette. MAIN MEASUREMENTS: Expired hydrogen peroxide using the Gallati and Pracht method. RESULTS: The S and NS groups showed comparable levels of H2O2-E at basal conditions [NS = 0.74 muM (DP 0.24) vs. S = 0.75 muM (DP 0.31)]. The smokers showed a significant increase in H2O2-E levels half an hour after the consumption of only one cigarette [0.75 muM (DP 0.31) vs. 0.95 muM (DP 0.22)]. CONCLUSION: The present results are consistent with the concept that smokers increase oxidative stress with elevated production of reactive oxygen species, contributing to the development of smoking-related disorders.
Acesso aberto (Open Access)
Myoglobin-H2O2 catalyzes the oxidation of beta-ketoacids to alpha-dicarbonyls: Mechanism and implications in ketosis
(Elsevier B.V., 2011-08-01) Ganini, Douglas; Christoff, Marcelo; Ehrenshaft, Marilyn; Kadiiska, Maria B.; Mason, Ronald P.; Bechara, Etelvino José Henriques [UNIFESP]; Universidade Federal de São Paulo (UNIFESP); Universidade de São Paulo (USP); Natl Inst Environm Hlth Sci
Acetoacetate (AA) and 2-methylacetoacetate (MAA) are accumulated in metabolic disorders such as diabetes and isoleucinemia. Here we examine the mechanism of AA and MAA aerobic oxidation initiated by myoglobin (Mb)/H2O2. We propose a chemiluminescent route involving a dioxetanone intermediate whose thermolysis yields triplet alpha-dicarbonyl species (methylglyoxal and diacetyl). the observed ultraweak chemiluminescence increased linearly on raising the concentration of either Mb (10-500 mu M) or AA (10-100 mM). Oxygen uptake studies revealed that MAA is almost a 100-fold more reactive than AA. EPR spin-trapping studies with MNP/MAA revealed the intermediacy of an alpha-carbon-centered radical and acetyl radical. the latter radical, probably derived from triplet diacetyl, is totally suppressed by sorbate, a well-known quencher of triplet carbonyls. Furthermore, an EPR signal assignable to MNP-AA(center dot) adduct was observed and confirmed by isotope effects. Oxygen consumption and a-dicarbonyl yield were shown to be dependent on AA or MAA concentrations (1-50 mM) and on H2O2 or tert-butOOH added to the Mb-containing reaction mixtures. That ferrylMb is involved in a peroxidase cycle acting on the substrates is suggested by the reaction pH profiles and immunospin-trapping experiments. the generation of radicals and triplet dicarbonyl products by Mb/H2O2/beta-ketoacids may contribute to the adverse health effects of ketogenic unbalance. (C) 2011 Elsevier Inc. All rights reserved.
Somente Metadadados
Natural Persulfate Activation for Anthracene Remediation in Tropical Environments
(Springer, 2017) Ferreira, Ieda D.; Prieto, Tatiana; Freitas, Juliana G.; Thomson, Neil R.; Nantes, Iseli L.; Bechara, Etelvino J. H. [UNIFESP]
In situ chemical oxidation using persulfate is one alternative to remediate polycyclic aromatic hydrocarbon-contaminated soil
Somente Metadadados
Relação entre o exercício aeróbio moderado e o estresse oxidativo induzido pelo peróxido de hidrogênio(H2O2) sobre a resposta contrátil de íleo isolado de camundongo
(Universidade Federal de São Paulo (UNIFESP), 2004) Vancini, Rodrigo Luiz [UNIFESP]; Nouailhetas, Viviane Louise Andreé [UNIFESP]
Introdução: Sabe-se que diferentes concentrações de H202 e exercícios de diferentes intensidades interferem no status oxidativo de tecidos e órgãos. Recentemente, demonstramos que a administração exógena de H202 e o exercício aeróbio moderado prejudicam a reatividade a diversos agentes estimulantes em íleo de cobaia e de camundongos C57BL/6, respectivamente. Objetivos: Neste trabalho, investigamos se os eventuais efeitos deletérios da administração exógena de H202 sobre a reatividade intestinal de camundongos C57BL/6 estariam relacionados ao nível de estresse oxidativo induzido por este peróxido, e se um programa de exercício aeróbio moderado protegeria este tecido dos eventuais efeitos deletérios da administração exógena de H202. Metodologia: Camundongos machos, com 3 meses de idade, foram subdivididos em grupos SED, EX 55 e NC, após uma semana de adaptação à corrida em esteira. O programa de exercício aeróbio moderado consistiu de uma sessão de 60 min/dia, 5 vezes/semana, durante 55 dias. Os parâmetros estudados foram a velocidade máxima atingida em um teste de velocidade incremental; a relação peso úmido do coração/peso corporal; o nível de estresse oxidativo dos músculos gastrocnêmio, masseter e do íleo, quantificado pela medida da reação dos produtos da peroxidação lipídica (PL) da membrana com o TBARs; a análise microscópica de cortes histológicos das fibras dos músculos gastrocnêmio, masseter e do íleo corados com hematoxilina/eosina. A reatividade foi estudada pelo registro da resposta contrátil isométrica disparada pelo KCI (acoplamento eletromecânico) ou CCh (acoplamento farmacomecânico) do íleo isolado banhado em solução de Tyrode, pH 7,4, borbulhados com ar e equilibrados a 37°C. A potência e a eficácia foram estudadas a partir de curvas concentrações-resposta aos agentes estimulantes (1,5 min de contato e 5 min de intervalo entre as concentrações), determinando-se os valores de CE50 (concentração do estimulante que provoca 50 por cento da resposta contrátil máxima) e da resposta máxima (Emáx). Os efeitos do H202 sobre a reatividade intestinal foram avaliados através de alterações dos valores de CE50 e do Emáx ao KCI e CCh de curvas concentrações-resposta feitas após o contato de 20 min com H202 0,012, 0,03 e 0,3 mM, seguida de lavagem exaustiva durante 10 min…(au).

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