The major unexplained phenomenon in fibrotic conditions is an increase in replicating fibroblasts. In this report we present evidence that oxygen free radicals can both stimulate and inhibit proliferation of cultured human fibroblasts, and that fibroblasts themselves release superoxide (O2.-) free radicals. Fibroblasts released O2.- in concentrations which stimulated proliferation, a finding co...

antibacterial, antifungal and antioxidant activities of methanolic crude extracts from aerial parts of four arnebia species namely arnebia fimbriopetala, arnebia linearifolia, arnebia garandiflora, arnebia tubata were screened. total phenolic contents were determined by folin-ciocalteu procedure and ranged from 2.2 ± 0.13 (a. fimbriopetala) to 1.6 ± 1.0 mg (arnebia tubata) gallic acid µmol equi...

We have developed a method to determine serum scavenging-capacity profile against multiple free radical species, namely hydroxyl radical, superoxide radical, alkoxyl radical, alkylperoxyl radical, alkyl radical, and singlet oxygen. This method was applied to a cohort of chronic kidney disease patients. Each free radical species was produced with a common experimental procedure; i.e., uv/visible...

Using ESR we have demonstrated the formation of the ascorbate free radical from sodium ascorbate, methylene blue and light. In oxygen uptake experiments we have observed the production of hydrogen peroxide while spin trapping experiments have revealed the iron catalyzed production of the hydroxyl free radical in this system. The presence of this highly reactive radical suggests that it could be...

Phleomycin induces DNA breakage in vitro in the presence of the sulphydryl compound dithiothreitol. The reaction appears to be free radical-mediated, and requires oxygen and metal ions. Reaction rate is limited by the concentration of oxygen, which is converted to hydrogen peroxide during DNA breakage. However there is no net change in the sulphydryl compound. The proposed reaction mechanism in...

Abstract Diabetes mellitus is one of the major metabolic disorders. Diabetes is recognized for severe complications including diabetic nephropathy, neuropathy and retinopathy. Long-lasting effect of hyperglycemia results in increased oxidative stress. Oxidative stress results from an imbalance between radical-generating and radical scavenging systems. Increased oxidative stress has been shown ...

the first reaction between food components and biological tissues occurs in the oral cavity. saliva modulates the ecosystem in the oral cavity and plays a critical role in oral homeostasis. in addition, saliva is a first line of defense against free radical-mediated stress. salivary antioxidant defense mechanisms seem to be very important. in this study we discuss in detail free radicals (fr) a...

The oxidation of L-cysteine by horseradish peroxidase in the presence of oxygen forms a thiyl free radical as demonstrated with the spin-trapping ESR technique. Reactions of this thiyl free radical result in oxygen consumption, which is inhibited by the spin trap 5,5'-dimethyl-1-pyrroline-N-oxide. Cysteine sulfinic acid, a cysteine metabolite, is a poorer substrate for horseradish peroxidase th...

Melatonin was discovered to be a direct free radical scavenger less than 10 years ago. Besides its ability to directly neutralize a number of free radicals and reactive oxygen and nitrogen species, it stimulates several antioxidative enzymes which increase its efficiency as an antioxidant. In terms of direct free radical scavenging, melatonin interacts with the highly toxic hydroxyl radical wit...