The present study investigates whether reactive oxygen species (ROS) are involved in p53 activation, and if they are, which species is responsible for the activation. Our hypothesis is that hydroxyl radical (.OH) functions as a messenger for the activation of this tumor suppressor protein. Human lung epithelial cells (A549) were used to test this hypothesis. Cr(VI) was employed as the source of...

Background. Oxygen-derived free radicals are thought to injure the ischemic heart during coronary microvascular embolization. Methods and Results. To test this idea, microspheres (15 gm in diameter) were repetitively administered into the left anterior descending coronary artery to cause microvascular embolization in dogs. Myocardial contractile and metabolic dysfunctions were significantly att...

UNLABELLED BACKGROUND Sonchus arvensis is used in the treatment of various human aliments as a traditional medicine in Pakistan. In the study its various fractions are characterized for scavenging of diverse free radicals. RESULTS Results of the present study revealed that various fractions of Sonchus arvensis significantly scavenged the free radicals (DPPH·, ABTS·+, ·OH, superoxide), howe...

Increased oxidative stress in diabetes mellitus may underlie the development of endothelial cell dysfunction by decreasing the availability of nitric oxide (NO) as well as by activating pro-inflammatory pathways. In the arterial wall, redox imbalance and oxidation of tetrahydrobiopterin (BH4) uncouples endothelial nitric oxide synthase (eNOS). This results in decreased production and increased ...

Methanolic extract of P. amarus was found to have potential anti-oxidant activity as it could inhibit lipid peroxidation, and scavenge hydroxyl and superoxide radicals in vitro. The amount required for 50% inhibition of lipid peroxide formation was 104 microg/ml and the concentrations needed to scavenge hydroxyl and superoxide radicals were 117 and 19 microg/ml respectively. The extract was fou...

We investigated the effects of polysaccharides from the brown seaweed Sargassum graminifolium (Turn.) (SGP) on calcium oxalate crystallization, and determined its antioxidant activities. To examine the effects of SGP on calcium oxalate crystallization, we monitored nucleation and aggregation of calcium oxalate monohydrate crystals, using trisodium citrate as a positive control. We assessed anti...

By means of the ESR spectrum technique it was demonstrated that fluoride (F-) stimulated human polymorphonuclear leukocytes (PMN) in a respiratory burst to generate active oxygen radicals ( • 02 and -OH) and to consume oxygen (02). The experiments' using the spin trapping technique with the nitrone DMPO as the trapping agent indicated that the PMN produce the adduct DMPO-OOH under high concentr...

To determine whether oxygen free radicals are responsible for the pathogenesis of the cholestasis induced by ligation of common bile duct (CBD) variables which reflect the hepatic function in the serum, the amount of superoxide radical production, and xanthine oxidase(XO) activity were studied. The activity of serum alanine aminotransferase, bilirubin level in the serum and the amount of supero...

Superoxide generated adventitiously by the mitochondrial respiratory chain can give rise to much more reactive radicals, resulting in random oxidation of all classes of macromolecules. Harman's 1956 suggestion that this process might drive aging has been a leading strand of biogerontological thinking since the discovery of superoxide dismutase. However, it has become apparent that the many down...

Treatment of Chinese hamster ovary and mouse hybridoma cells with Mega-H brand silica hydride, a marketed antioxidant, after photosensitization with singlet oxygen and hydroxyl/superoxide reactive oxygen species through the use of rose bengal diacetate and malachite green resulted in an effective method of reducing free radical activity by more than 96% against singlet oxygen species and more t...