120 research outputs found
Evaluation of Antioxidant Parameters in Rats Treated with Sevoflurane
SummaryBackground and objectivesSevoflurane is a halogenated fluorinated ether that undergoes hepatic biotransformation through cytochrome P4502E1. Halogenated ethers undergoing biotransformation by P4502E1 can produce reactive oxygen species (ROS), weakening the antioxidant defense mechanism. The objective of this study was to investigate the relationship between the activity of erythrocyte antioxidant enzymes and sevoflurane.MethodsAnimals were divided in four groups: Group 1 – control: 100% oxygen (1 L.min-1 for 60 min during five consecutive days); Group 2 – 4.0% sevoflurane in 100% oxygen (1 L.min-1 for 60 minutes during five consecutive days); Group 3 – isoniazid (i.p.), 50 mg.kg-1/day for four consecutive days, followed by 100% oxygen (1 L.min-1 for 60 minutes during four consecutive days); Group 4 – intraperitoneal isoniazid, 50 mg.kg-1 daily for four days, followed by 4.0% sevoflurane in 100% oxygen (1 L.min-1 for 60 minutes during five days). Twelve hours after the last exposure to sevoflurane, animals were sacrificed and their blood was collected through the portal vein for analysis of antioxidant enzymes.ResultsAn increase in the activity of glucose-6-phosphate dehydrogenase and a decrease in the activity of catalase were observed, especially in the group of animals pre-treated with isoniazid. Changes in the activity of glutathione peroxidase were not observed.ConclusionsThe interaction between sevoflurane and cytochrome P450 2E1 with enzymatic inducers can lead to oxidative stress with prolonged and repetitive exposure
Mycelial glucoamylases produced by the thermophilic fungus Scytalidium thermophilum strains 15.1 and 15.8: purification and biochemical characterization
A tecnologia como referência dos saberes escolares: perspectivas teóricas e concepções dos professores
Levels of true digestible lisiane and metabolizable energy for growing pigs: effect on nitrogen and energy balance
Microrganismos heterotróficos mesófilos e bactérias do grupo do Bacillus cereus em leite integral submetido a ultra alta temperatura
Atmospheric effects on extensive air showers observed with the Surface Detector of the Pierre Auger Observatory
Atmospheric parameters, such as pressure (P), temperature (T) and density,
affect the development of extensive air showers initiated by energetic cosmic
rays. We have studied the impact of atmospheric variations on extensive air
showers by means of the surface detector of the Pierre Auger Observatory. The
rate of events shows a ~10% seasonal modulation and ~2% diurnal one. We find
that the observed behaviour is explained by a model including the effects
associated with the variations of pressure and density. The former affects the
longitudinal development of air showers while the latter influences the Moliere
radius and hence the lateral distribution of the shower particles. The model is
validated with full simulations of extensive air showers using atmospheric
profiles measured at the site of the Pierre Auger Observatory.Comment: 24 pages, 9 figures, accepted for publication in Astroparticle
Physic
The Fluorescence Detector of the Pierre Auger Observatory
The Pierre Auger Observatory is a hybrid detector for ultra-high energy
cosmic rays. It combines a surface array to measure secondary particles at
ground level together with a fluorescence detector to measure the development
of air showers in the atmosphere above the array. The fluorescence detector
comprises 24 large telescopes specialized for measuring the nitrogen
fluorescence caused by charged particles of cosmic ray air showers. In this
paper we describe the components of the fluorescence detector including its
optical system, the design of the camera, the electronics, and the systems for
relative and absolute calibration. We also discuss the operation and the
monitoring of the detector. Finally, we evaluate the detector performance and
precision of shower reconstructions.Comment: 53 pages. Submitted to Nuclear Instruments and Methods in Physics
Research Section
Análise econômica da produção de Acacia mearnsii De Wild e carvão vegetal no Vale do Caí e Taquari, Rio Grande do Sul
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