Methanogenesis is a major metabolic pathway long associated with strictly anaerobic conditions predominantly due in part to the high sensitivity of obligate methanogenic archaea to oxygen toxicity. However, there is increasing evidence that methanogenic archaea can survive prolonged periods of oxygen stress in both pure culture and environmental conditions. The molecular defense mechanisms agai...

This review examines the role of oxidative stress in damage to cells of the trabecular meshwork and associated impaired aqueous drainage as well as damage to retinal ganglion cells and associated visual field losses. Consideration is given to the interaction between vascular and mechanical explanations for pathological changes in glaucoma. For example, elevated intraocular pressure (IOP) forces...

neurodegeneration is a complex and multifaceted process leading to many chronic disease states. a conventional definition implies a progressive neuronal death, which usually affects a specific population of nerve cells the vulnerability of which determines the clinical manifestations of a particular neurodegenerative disease. the neurodegenerative process is associated with many events. each ev...

Diabetic nephropathy is strongly associated with both increased oxidative stress and kidney tissue hypoxia. The increased oxidative stress causes increased kidney oxygen consumption resulting in kidney tissue hypoxia. To date, it has been difficult to determine the role of kidney hypoxia, per se, for the development of nephropathy. We tested the hypothesis that kidney hypoxia, without confoundi...

Cardiotonic agents influence myocardial energy consumption by vasodilation, which may reduce energy demand, and by inotropism, which may increase it. To distinguish between the two effects, myocardial oxygen consumption must be analyzed in relation to its hemodynamic determinants. The coupling of myocardial oxygen consumption with its determinants was investigated in 22 patients with idiopathic...

background: an increased oxidative stress in patients under treatment with high concentrations of oxygen (hyperoxia) is considered to be one of the major mechanisms of lung injury. between different mediators, transition metal ions especially iron, by generation of very reactive free radicals play an important role in oxidative stress process. disruption of normal iron hemostasis has been repor...

At high altitudes, the air pressure is much lower than it is at sea level and contains fewer oxygen molecules and less oxygen is taken in at each breath. This requires deeper and rapid breathing to get the same amount of oxygen into the blood stream compared to breathing in air at sea level. Exercises increase the oxygen demand and make breathing more difficult at high altitude. In this study, ...

A major cause of male infertility, which includes 50 causes of infertility, is oxidative stress.  The aerobic respiration in the sperm cell is associated with the production of reactive oxygen species (ROS). Some reactions such as sperm capacitation and acrosome reactions require moderate levels of ROS. However, when the amount of ROS production surpasses the natural antioxidant defense of the ...

Plants activate antioxidant defense mechanisms under stress, which help maintaining the structural integrity of cell components and possibly reduces oxidative damage.  Low temperature stress leads to the production of reactive oxygen species and oxidative damage to plants. In this study, the effect of putrescine and proline on reducing the production of reactive oxygen species and increasing th...

Stress can alter the functional status of the animal through a chain of complex interactions. In this work, influence of stress on oxygen consumption and rectal temperature was studied in parabiotic albino rats, to show the possibility of involvement of humoral factors. Stress has resulted in fall in rectal temperature and increase or decrease in oxygen consumption even when one animal of the p...