To determine if oxygen-derived free radicals are mediators of endothelium-dependent contractions to acetylcholine in the aorta of spontaneously hypertensive rats (SHR), the mechanism of contraction to xanthine plus xanthine oxidase was studied. Rings, with and without endothelium, of thoracic aorta from normotensive Wistar-Kyoto (WKY) rats and SHR were suspended in organ chambers for isometric ...

Researchers have recently shown an increased interest in free radicals and their role in the tumor microenvironment. Free radicals are molecules with high instability and reactivity due to the presence of an odd number of electrons in the outermost orbit of their atoms. Free radicals include reactive oxygen and nitrogen species, which are key players in the initiation and progression of tumor c...

Oxygen-derived free radical formation can lead to cellular injury and death. Under normal situations, the human body has a free radical scavenger system (catalase, superoxide dismutase) that can detoxify free radicals. Antioxidant vitamins and enzymatic and synthetic oxygen-derived free radical scavengers have been used clinically to prevent the formation of oxidized LDL and to prevent reperfus...

Oxygen free radicals are known to be generated during periods of ischemia followed by reperfusion. There is still some controversy, however, concerning the use of electron paramagnetic resonance spectroscopy to accurately detect and identify the free radical species that are formed. There is no doubt that oxygen radicals are deleterious to the myocardium; free radicals cause left ventricular dy...

Objective; Tympanosclerosis is a common sequela of tympanoplasty operations causing hearing disability. It is associated with an increased production of free radicals (also known as reactive oxygen species) after trauma. Vitamin E is a scavenger of different free radicals by working as an antioxidant. The aim of the present study was to evaluate the effect of vitamin E-soaked absorbable gelatin...

Reactive oxygen species comprise oxygen-based free radicals and non-radical such as peroxynitrite electronically excited (singlet) oxygen. These reactive often have short lifetimes, much of our understanding their formation reactivity in biological especially medical environments has come from complimentary fast reaction methods involving pulsed lasers high-energy radiation techniques. related ...