ABSTRACT
Aerobic life is characterized by a steady generation of reactive oxygen species balanced by a similar rate of their consumption by antioxidants. To maintain homeostasis, there is a requirement for the continuous regeneration of antioxidant capacity, and if this is not met, oxidative stress occurs, resulting in pathophysiological events. Cellular protection against oxidative stress is organized at multiple levels. Defense strategies include prevention, interception, replacement, and repair. These mechanisms are coupled to the intermediary metabolism for a continuous supply of energy, reducing equivalents, and precursors, and depend on the dietary supply of metabolic fuels and essential molecules to allow an optimal cellular functioning
Subject(s)
Humans , Antioxidants/metabolism , Catalase/physiology , Glutathione Peroxidase/physiology , Oxidative Stress/physiology , Peroxidases/physiology , Reactive Oxygen Species/physiology , Superoxide Dismutase/physiology , Free Radicals/metabolismABSTRACT
1. Recent research on experimental animals indicates that thyroid hormone administration is associated with greater electron flow through the microsomal, mitochondrial, and peroxisomal electron transport systems of the liver, as indicated by the enhanced production of superoxide radicals (O2.-) and/or hydrogen proxide (H2O2). 2. Hyperthyroidism induces an increased respiratory burst activity in rat and human polymorphonuclear leukocytes, an effect that seems to be related to changes in the myeloperoxidase-H2O2 system of the cell, rather than to the direct actions of the hormone or changes in the opsonic capacity of plasma. 3. These findings indicate that thyroid calorigenesis involves an elevated prooxidant activity in target cells, which may be relevant in determining toxic effects within the tissue or in neighboring cells
Subject(s)
Animals , Humans , Male , Female , Adult , Respiratory Burst/physiology , Thyroid Hormones/physiology , Neutrophils/physiology , Body Temperature , Electron Transport , Thyroid Hormones/blood , Oxygen Consumption , Rats, Sprague-DawleyABSTRACT
Urinary visible luminescence is the result of the excretion of oxidized biomolecules and, as such, could provide a valuable index of systemic oxidative stress. The characteristics of the urinary luminescence that support this proposal are reviewed and the data obtained for patients with hyperthyroidism and children with Duchenne muscular dystrophy are also discussed. Enhanced urinary chemiluminescence was observed in both pathologies. A similar enhancement was obtained when the urinary luminescence of smokers was compared to that of non-smokers. The possibilities and limitations of this noninvasive methodology for the evaluation of systemic oxidative stress is critically evaluated.
Subject(s)
Humans , Child , Luminescent Measurements , Oxidative Stress , Urine , Creatinine , Free Radicals , Hydrogen-Ion Concentration , Hyperthyroidism , Muscular Dystrophies , Oxidation-Reduction , Smoking , Time FactorsABSTRACT
Se revisan los principales mecanismos de alteracion del transporte y utilizacion de oxigeno en el hombre, incluyendo desde alteraciones del aire atmosferico hasta lesiones intracelulares. Se mencionan efectos frecuentes y caracteristicos de enfermedades y causas que provocan hipoxemia, hipoxia y dano celular. Tambien son analizados algunos efectos toxicos de oxigeno