Protection of insulin-producing cells against toxicity of dexamethasone by catalase overexpression

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

Lipid peroxidation and generation of hydrogen peroxide in frozen-thawed ram semen supplemented with catalase or Trolox

Semen manipulation and cryopreservation-thaw procedures may accelerate the generation of reactive oxygen species (ROS). Sperm exposure to large amounts of ROS has been shown to cause membrane lipid peroxidation and cellular injury to the sperm. The objective of this study was to overcome the ROS production in frozen-thawed ram semen by the addition of the antioxidants catalase or Trolox to semen following thawing. Frozen-thawed ram semen (100 x 10(6) sperm/straw) was supplemented with PBS (control group), 100 mu g/ml catalase, or 100 mu M Trolox/10(8) sperm (catalase and Trolox being dissolved in PBS) and incubated (37 degrees C) for 5 min. Under the experimental conditions used in this study, the catalase and Trolox antioxidants failed to protect the sperm from the spontaneous production of ROS. However, when lipid peroxidation was induced by iron (FeSO(4)), the addition of Trolox promoted a reduction (P < 0.05) in the formation of TBARS in the semen, compared to the control and catalase semen samples. The generation of TBARS and H(2)O(2) occurred in the extender alone, without the presence of sperm cells. In conclusion, the addition of Trolox to frozen-thawed ram semen could be beneficial as it decreases the production of TBARS when oxidative stress is induced. It is possible that a longer incubation period could lead to different results. The concentration of catalase also needs to be further evaluated. The extender could contribute to the oxidative stress of sperm, as it is a source of ROS during the cryopreservation of semen. (C) 2010 Elsevier B.V. All rights reserved.

PRODUCTION of FREE RADICALS and CATALASE ACTIVITY DURING ACUTE EXERCISE TRAINING IN YOUNG MEN

Reactive oxygen species (ROS) are constantly produced by cells that promote cellular oxidative damage and are neutralized by an antioxidant system including superoxide dismutase, glutathione, peroxidase and catalase. Male volunteers were exercised for 20 minutes, three days (60, 70 and 80% of maximum heart rate). Catalase activity and plasma malondialdehyde concentration were measured. The mean age of the volunteers was 25 +/- 7 years, with body mass index 2 of 24.03 +/- 4.32 kg/m(2). Acute exercise training produced an increase of malondialdehyde concentration that was exercise intensity-dependent in young volunteers. However, catalase activity shows a great variability at baseline and the percentual of reduction was exercise intensity-independent in this particular population. Therefore, our study shows that acute cycling exercise promotes an increase of oxidative stress that was exercise intensity-dependent in young volunteers. Furthermore, the antioxidant system measured by catalase activity was effective to counterbalance the ROS production showing a saturation behavior at an intensity of 70% of maximum heart rate.

The Water Effect on the Kinetics of the Bovine Liver Catalase

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Catalase activity of different Candida species after exposition to specific antiserum

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

Effects of the administration of a catalase inhibitor into the fourth cerebral ventricle on cardiovascular responses in spontaneously hypertensive rats exposed to sidestream cigarette smoke

OBJECTIVE: ,,,,,Previous studies have demonstrated a relationship between brain oxidative stress and cardiovascular regulation. We evaluated the effects of central catalase inhibition on cardiovascular responses in spontaneously hypertensive rats exposed to sidestream cigarette smoke. ,,,, ,,,, ,,,,,METHODS: ,,,,,Male Wistar Kyoto (WKY) rats and spontaneously hypertensive rats (SH) (16 weeks old) were implanted with a stainless steel guide cannula leading into the fourth cerebral ventricle (4th V). The femoral artery and vein were cannulated for arterial pressure and heart rate measurement and drug infusion, respectively. The rats were exposed to sidestream cigarette smoke for 180 minutes/day, 5 days/week for 3 weeks (CO: 100-300 ppm). The baroreflex was tested using a pressor dose of phenylephrine (8 μg/kg, bolus) and a depressor dose of sodium nitroprusside (50 μg/kg, bolus). Cardiovascular responses were evaluated before and 5, 15, 30 and 60 minutes after injection of a catalase inhibitor (3-amino-1,2,4-triazole, 0.001 g/100 μL) into the 4th V. ,,,, ,,,, ,,,,,RESULTS: ,,,,,Vehicle administration into the 4th V did not affect the cardiovascular response, whereas administration of the central catalase inhibitor increased the basal HR and attenuated the bradycardic peak (p<0.05) to a greater extent in WKY rats exposed to sidestream cigarette smoke than in WKY rats exposed to fresh air. However, in spontaneously hypertensive rats, the effect of the catalase inhibitor treatment was stronger in the fresh air condition (p<0.05). ,,,, ,,,, ,,,,,CONCLUSION: ,,,,,Administration of a catalase inhibitor into the 4th V combined with exposure to sidestream cigarette smoke has a stronger effect in WKY rats than in SH rats.

Electrophoretic variants of intracellular catalase of different Candida species

Intracellular and extracellular catalases of different species of Candida were investigated using different culture media. All the Candida strains produced intracellular catalase, whose enzymatic activity was detected by non-denaturating polyacrylamide gradient (4-30%) gel electrophoresis. The cell extracts presented a major 230 kDa catalase band and in some strains variants of catalase with different molecular weights were detected. Candida catalase activity was not affected by heating at 50degreesC and incubation with beta-mercaptoethanol, but treatment with sodium dodecyl sulphate inhibited or reduced enzymatic activity. Extracellular enzyme activity was not detected in any of the culture filtrate extracts tested.

Efeito da adição de Trolox® e catalase ao meio glicina-gema-leite sobre o sêmen caprino refrigerado por 24 ou 48 horas em sistema Equitainer®

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Influência dos níveis de ferritina sérica, das mutações no gene da beta globina e dos valores das enzimas de detoxificação Catalase e Glutationa S -Transferase na expressão fenotípica de Beta Talassemia Heterozigota

Pós-graduação em Genética - IBILCE

Prevenção do estresse oxidativo pela utilização de trolox®, catalase e glutationa no processo de congelação de sêmen ovino

Pós-graduação em Medicina Veterinária - FMVZ

Viabilidade espermática e geração de metabólicos reativos do oxigênio(ROS) no sêmen ovino criopreservado em diluidor aditivado de lauril de sódio (OE), trolox-C e catalase

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

Cardiovascular Responses Induced by Catalase Inhibitior into the Fourth Cerebral Ventricle is Changed in Wistar Rats Exposed to Sidestream Cigarette Smoke

Objectives: This experimental study aimed to evaluate the effects of central catalase inhibition on cardiovascular responses in rats exposed to sidestream cigarette smoke (SSCS) for 3 weeks. Methodology: A total of 20 males Wistar rats (320–370g) were implanted with a stainless steel guide cannula into the fourth cerebral ventricle (4thV). Femoral artery and vein were cannulated for mean arterial pressure (MAP) and heart rate (HR) measurement and drug infusion, respectively. Rats were exposed to SSCS for three weeks, 180 minutes per day, 5 days/week [carbon monoxide (CO): 100–300 ppm)]. Baroreflex was tested with one pressor dose of phenylephrine (PHE, 8 μg/kg, bolus) and one depressor dose of sodium nitroprusside (SNP, 50 μg/kg, bolus). Cardiovascular responses were evaluated before and 15 minutes after 3-amino-1, 2, 4-triazole (ATZ, catalase inhibitor, 0.001g/100μL) injection into the 4th V. Results: Vehicle treatment into the 4th V did not change cardiovascular responses. Central catalase inhibition increased tachycardic peak, attenuated bradycardic peak and reduced HR range at 15 minutes, increased MAP at 5, 15 and 30 min and increased HR at 5 and 15 min. In rats exposed to SSCS, central ATZ increased basal MAP after 5 min and increased HR at 5, 15 and 30 minutes, respectively, and attenuated bradycardic peak at 15 minutes. Conclusion: This study suggests that brain oxidative stress caused by SSCS influences autonomic regulation of the cardiovascular system.