Navegando por Palavras-chave "alpha-tocopherol"
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- ItemSomente Metadadadosalpha-Tocopherol modulates tyrosine phosphorylation in human neutrophils by inhibition of protein kinase C activity and activation of tyrosine phosphatases(Taylor & Francis Ltd, 2001-01-01) Chan, S. S.; Monteiro, H. P.; Schindler, F.; Stern, A.; Junqueira, VBC; Universidade Federal de São Paulo (UNIFESP); Universidade de São Paulo (USP); Fdn Pro Sangue; NYUalpha-Tocopherol augmentation in human neutrophils was investigated for effects on neutrophil activation and tyrosine phosphorylation of proteins, through its modulation of protein kinase C (PKC) and tyrosine phosphatase activities. Incubation of neutrophils with alpha-tocopherol succinate (TS) resulted in a dose-dependent incorporation into cell membranes, up to 2.5 nmol/2 X 10(6) cells. A saturating dose of TS (40 mumol/l) inhibited oxidant production by neutrophils stimulated with phorbol myristate acetate (PMA) or opsonized zymosan (OZ) by 86 and 57%, as measured by luminol-amplified chemiluminescence (CL). With PMA, TS inhibited CL generation to a similar extent to staurosporine (10 nmol/l) or genistein (100 mumol/l), and much more than Trolox (40 mumol/l). With OZ, TS inhibited CL to a similar extent to Trolox. Neutrophil PKC activity was inhibited 50% or more by TS or staurosporine. the enzyme activity was unaffected by genistein or Trolox, indicating a specific interaction of alpha-tocopherol. TS or Trolox increased protein tyrosine phosphorylation in resting neutrophils, and as with staurosporine further increased tyrosine phosphorylation in PMA-stimulated neutrophils, while the tyrosine kinase (TK) inhibitor genistein diminished phosphorylation. These effects in resting or PMA-stimulated neutrophils were unrelated to protein tyrosine phosphatase (PTP) activities, which were maintained or increased by TS or Trolox. in OZ-stimulated neutrophils, on the other hand, all four compounds inhibited the increase in tyrosine-phosphorylated proteins. in this case, the effects of pre-incubation with TS or Trolox corresponded with partial inhibition of the marked (85%) decrease in PTP activity induced by OZ. These results indicate that alpha-tocopherol inhibits PMA-activation of human neutrophils by inhibition of PKC activity, and inhibits tyrosine phosphorylation and activation of OZ-stimulated neutrophils also through inhibition of phosphatase inactivation.
- ItemSomente Metadadadosalpha-Tocopherol supplementation avoids apoptosis in the anal sphincter(Informa Healthcare, 2012-03-01) Silva, Romualdo Correa da [UNIFESP]; Reis, Leonardo Oliveira; Lorenzetti, Fabio [UNIFESP]; Palma, Paulo; Ortiz, Valdemar [UNIFESP]; Dambros, Miriam [UNIFESP]; Universidade Federal de São Paulo (UNIFESP); Universidade Estadual de Campinas (UNICAMP)Purpose: To analyze the influence of alpha-tocopherol supplementation on the levels of oxidative stress and apoptosis rates in the anal sphincter induced by orchiectomy in rats. Methods: Forty male Wistar rats weighing 250-300 g, were divided into four groups and sacrificed 8 weeks after: I- Control: sham; II- Orchiectomy: bilateral orchiectomy; III- Pre Orchiectomy Tocopherol: alpha-tocopherol supplementation for 4 weeks preceding bilateral orchiectomy; IV- Orchiectomy Full Tocopherol: alpha-tocopherol supplementation for 4 weeks before and 8 weeks after bilateral orchiectomy. the anal sphincter was analyzed stereologically to evaluate the density of collagen and the muscle fibers. the oxidative stress and the apoptosis were determined with 8-isprostane and caspase-3, respectively. Results: the collagen fibers concentration was statistically greater in Orchiectomy group than the others. the muscle fibers concentration was higher in Control and Orchiectomy Full Tocopherol than Orchiectomy and Pre Orchiectomy Tocopherol groups. Orchiectomy group showed higher 8-isoprostane concentrations compared to the other groups (p < 0.0003). Pre Orchiectomy Tocopherol and Orchiectomy Full Tocopherol groups presented caspase-3 levels lower than the Orchiectomy group (0.0072). Conclusion: Vitamin supplementation with alpha-tocopherol for 12 weeks had the highest protection against bilateral orchiectomy generation of reactive oxygen species as well as apoptosis in the muscle fibers of the anal sphincter of rats.
- ItemSomente MetadadadosAscorbic acid and alpha-tocopherol attenuate methylmalonic acid-induced convulsions(Lippincott Williams & Wilkins, 1999-07-13) Fighera, M. R.; Queiroz, C. M.; Stracke, M. P.; Brauer, MCN; Gonzalez-Rodriguez, L. L.; Frussa, R.; Wajner, M.; Mello, C. F. de; Universidade Federal de Sergipe (UFS); Universidade Federal de São Paulo (UNIFESP); Univ Fed Rio Grande SulTHE effects of chronic administration of alpha-tocopherol or melatonin, or acute ascorbic acid administration on the convulsant action of methylmalonic acid (MMA) were investigated in adult male rats. Animals were chronically injected with alpha-tocopherol (40 mg kg(-1), i.p.), melatonin (5 mg kg(-1), i.p.) or vehicle for 7 days. Buffered MMA (6 mu mol/2 mu l) or NaCl (9 mu mol/2 mu l) was injected intrastriatally and the animals were observed for the appearance of clonic or tonic-clonic convulsions and rotational behavior. Ascorbic acid (100 mg kg(-1), s.c.) was administered 30 min before MMA injection. alpha-Tocopherol and ascorbic acid pretreatment decreased the duration of the convulsive episodes and the rotational behavior elicited by MMA, This study provides evidence that free radical generation may participate in the convulsant effects of methylmalonic acid. NeuroReport 10:2039-2043 (C) 1999 Lippincott Williams & Wilkins.
- ItemSomente MetadadadosContent of liver and brain ubiquinol-9 and ubiquinol-10 after chronic ethanol intake in rats subjected to two levels of dietary alpha-tocopherol(Harwood Acad Publ Gmbh, 2000-01-01) Junqueira, VBC; Carrasquedo, F.; Azzalis, L. A.; Giavarotti, KAS; Giavarotti, L.; Rodrigues, L.; Fraga, C. G.; Boveris, A.; Videla, L. A.; Universidade Federal de São Paulo (UNIFESP); Univ Buenos Aires; Universidade de São Paulo (USP); Univ ChileTo assess the effect of chronic ethanol ingestion in the content of the reduced forms of coenzymes Q(9) (ubiquinol-9) and Q(10) (ubiquinol-10) as a factor contributing to oxidative stress in liver and brain, male Wistar rats were fed ad libitum a basal diet containing either 10 or 2.5 mg alpha-tocopherol/100% diet (controls), or the same basal diet plus a 32% ethanol-25% sucrose solution. After three months treatment, ethanol chronically-treated rats showed identical growth rates to the isocalorically pair-fed controls, irrespectively of alpha-tocopherol dietary level. Lowering dietary alpha-tocopherol led to a decreased content of this vitamin in the liver and brain of control rats, without changes in that of ubiquinol-9, and increased levels of hepatic ubiquinol-10 and total glutathione (tGSH), accompanied by a decrease in brain tGSH. At the two levels of dietary alpha-tocopherol, ethanol treatment significantly decreased the content of hepatic alpha-tocopherol and ubiquinols 9 and 10. This effect was significantly greater at 10 mg alpha-tocopherol/100% diet than at 2.5, whereas those of tGSH were significantly elevated by 43% and 9%, respectively. Chronic ethanol intake did not alter the content of brain alpha-tocopherol and tGSH, whereas those of ubiquinol-9 were significantly lowered by 20% and 14% in rats subjected to 10 and 2.5 mg alpha-tocopherol/100 g diet, respectively. It is concluded that chronic ethanol intake at two levels of dietary alpha-tocopherol induces a depletion of hepatic alpha-tocopherol and ubiquinols 9 and 10, thus contributing to ethanol-induced oxidative stress in the liver tissue. This effect of ethanol is dependent upon the dietary level of alpha-tocopherol, involves a compensatory enhancement in hepatic tGSH availability, and is not observed in the brain tissue, probably due to its limited capacity for ethanol biotransformation and glutathione synthesis.
- ItemAcesso aberto (Open Access)Impact of castration with or without alpha-tocopherol supplementation on the urethral sphincter of rats(Sociedade Brasileira de Urologia, 2012-04-01) Kracochansky, Mirian [UNIFESP]; Reis, Leonardo Oliveira; Lorenzetti, Fábio [UNIFESP]; Ortiz, Valdemar [UNIFESP]; Dambros, Miriam [UNIFESP]; Universidade Federal de São Paulo (UNIFESP); Universidade Estadual de Campinas (UNICAMP)OBJECTIVE: To analyze the impact of low levels of testosterone induced by orchiectomy and the effect of alpha-tocopherol supplementation on oxidative stress in the urethral sphincter. MATERIALS AND METHODS: Forty male Wistar rats weighing 250-300g were divided into four groups with 10 each: Sham group; Orchiectomy group: bilateral orchiectomy; Orchiectomy-pre-Tocopherol group: bilateral orchiectomy preceded by alpha-tocopherol supplementation for four weeks; Orchiectomy-full-Tocopherol group: bilateral orchiectomy with alpha-tocopherol supplementation for four weeks preceding the procedure and for eight weeks afterwards. At the protocol end, animals were euthanized and had the sphincter analyzed stereologically focusing on collagen and muscle fibers percentage. Oxidative stress levels were determined using 8-epi-PGF2. RESULTS: The 8-epi-PGF2 levels were statistically higher (p < 0.0003) in the Orchiectomy group compared to others groups while Sham and Orchiectomy-full-Tocopherol groups presented statistically similar values (p = 0.52). Collagen volumetric densities were significantly lower in Sham and Orchiectomy-full-Tocopherol groups (p < 0.022). Sham group presented statistically greater muscle fiber percent. CONCLUSION: Castration caused oxidative stress in the urethral sphincter complex, with increased collagen deposition. Alpha-tocopherol had a protective effect and its supplementation for twelve weeks provided the greatest protection.
- ItemAcesso aberto (Open Access)A suplementação de antioxidantes inibe o processo de apoptose na parede vesical de ratos submetidos à privação androgênica(Universidade Federal de São Paulo (UNIFESP), 2009-02-27) Ludwig, Luana [UNIFESP]; Dambros, Miriam [UNIFESP]; Universidade Federal de São Paulo (UNIFESP)Ludwig, Luana. A suplementação de antioxidantes inibe o processo de apoptose na parede vesical submetida à privação androgênica. [Antioxidant supplementation inhibits apoptosis in blader wall subjected to sndrogen deprivation]. Orientadora: Miriam Dambros. São Paulo: s.n, 2009. [46]. Dissertação(Mestrado em Urologia)-Universidade Federal de São Paulo. Escola Paulista de Medicina. Resumo: Introdução: Dentre as disfunções vesicais a bexiga hiperativa afeta negativamente a população idosa. Respeitando os princípios básicos da hiperatividade do detrusor, grande evidência tem se mostrado que a geração de radicais livres participa no processo de desenvolvimento da bexiga hiperativa, e durante 0 envelhecimento celular de organismos, este processo é intensificado colaborando para um aumento no dano de DNA. Objetivo: Avaliar os efeitos do hipogonadismo (usando um modelo de envelhecimento induzido) no processo de apoptose celular na parede vesical de ratos machos orquiectomizados e do efeito protetor da suplementação de alfa-tocoferol. Material e Métodos: Foram empregados 4 grupos de 10 ratos Wistar machos: grupo I (controle); grupo II (orquiectomia bilateral); grupo III (orquiectomia bilateral e suplementação prévia com alfa-tocoferol por 4 semanas); grupo IV (orquiectomia bilateral, suplementação prévia com alfa-tocoferol por 4 semanas e nas 8 semanas seguintes). Todos os ratos foram sacrificados após 8 semanas, e amostras de sangue foram coletadas para dosagem de testosterona e 8-epi-PGF2. A bexiga foi removida ao nível do colo vesical, fixada em formal 10% e processada em parafina e submetida a secções de 5μm para imuno-histoquímica. A presença de caspase-3 ativada foi detectada através de técnica descrita por Brown, 1996 (1). A avaliação estatística empregou métodos não paramétricos e nível de significância de 5%. Resultados: As concentrações séricas de testosterona ao final do experimento, nos grupos II, III e IV foram menores do que 20 pg/mL. A análise do isoprostano 8-epi-PGF2 mostrou diferença estatisticamente significativa do grupo II em relação aos demais (p<0,0003). A densidade volumétrica da caspase-3 mostrou diferença significativa quando os grupos foram comparados (p=0,0023). 0 grupo II apresentou 0 maior nível de morte celular que os demais. Conclusão: Nossos resultados demonstraram que 0 processo apoptótico na parede vesical foi mais expressivo no grupo II do que nos outros. A suplementação com alfa¬-tocoferol atenuou significativamente 0 estresse oxidativo e morte celular na musculatura detrusora. Estes resultados sugerem que 0 estresse oxidativo causado pela castração cirúrgica em ratos machos pode estar envolvido na indução de apoptose. Além disso, a administração de um antioxidante reduziu significativamente a apoptose na parede vesical submetidos à privação androgênica. 0 que corrobora com a hipótese da influência de radicais livres no processo de morte celular na bexiga de ratos.