Free oxygen radicals are an irrefutable component of life, underlying important biochemical and physiological phenomena in animals. Here it is shown that free oxygen radicals activate plasma membrane Ca(2+)- and K(+)-permeable conductances in Arabidopsis root cell protoplasts, mediating Ca(2+) influx and K(+) efflux, respectively. Free oxygen radicals generate increases in cytosolic Ca(2+) medi...

oxygen-derived free radical* (ofr) involvement in ischacmia-rcpcrfusion (ir) injury was investigated in a rat isolated kidney model, using 20 minutes iscliaemia followed by 15 or 60 minutes reperfusion. two antioxidants, the xanthine oxidase inhibitor allopurinol and the hydroxyl radical scavenger dimcthylthiourca (dmtu), were uscit to try and prevent ofr-relatcd damage. renal function was esti...

Hypoxia, reactive oxygen species (ROS) and oxidative stress contribute to contrast-induced acute kidney injury (CI-AKI) and ischemic reperfusion injury (IRI) in the kidney and heart. Imbalance between the increased formation of ROS by hypoxia in the cardiac and renal tissue and the low availability of endogenous antioxidants is a common cause of cellular and tissue damage. Therefore, a strategy...

BACKGROUND AND PURPOSE Cardiac arrest and resuscitation in immature piglets result in a delayed increase in blood-brain barrier permeability. We tested the hypothesis that pretreatment with oxygen radical scavengers reduces postischemic permeability. METHODS Permeability was assessed by measuring the plasma-to-brain transfer coefficient of the small amino acid, alpha-aminoisobutyric acid, in ...

Currently, there is a great deal of interest in the study of natural compounds with free-radical-scavenging activity because of their potential role in maintaining human health and preventing diseases. In this paper, we report the antioxidant and cytoprotective properties of 2,4,8-trihydroxybicyclo [3.2.1]octan-3-one (TBO) isolated from the aqueous extract of Decalepis hamiltonii roots. Our res...

It has been proposed that oxygen free radicals mediate damage that occurs during postischemic reperfusion. Recombinant human superoxide dismutase (r-h-SOD) has been shown to be effective at reducing reperfusion injury, but it is not known if this infused enzyme actually reduces oxygen free radical concentrations in the myocardial tissue. Electron paramagnetic resonance spectroscopy was used to ...

BACKGROUND Airway inflammation represents the basis of respiratory allergic disease and is generally associated with increased oxidative stress. As a consequence of successful treatment leading to hyposenzibilization and remission of symptoms, decrease of reactive oxygen formation is expected. MATERIAL/METHODS This preliminary study evaluates the production of oxygen free radicals in white bl...

The polyamines, relatively low-molecular-weight aliphatic compounds, are the main inducers of eukaryotic cell growth and proliferation. Although polyamine requirements for cell growth are well defined, their role is still enigmatic. We have previously reported that amyloid beta-peptide (A beta), the main constituent of senile plaques in Alzheimer's disease (AD) brain, is toxic to neurons throug...

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...