The implantation of foreign material carries a risk of infection which frequently is resistant to all treatment short of removing the implant. We have previously shown that these materials activate neutrophils by contact, leading to production of oxygen free radicals accompanied by release of granule products. Such activation further results in depletion of local host defenses, including the ca...

Background and objectives: Natural product compounds of plants have been used since ancient times and in folklore medicine for the treatment of many diseases and illnesses. Oxygen-centered free radicals and other reactive oxygen species, which are continuously, produced in vivo, result in cell death and tissue damage. Oxidative damage caused by free radicals may be rel...

Free radicals and other active derivatives of oxygen are inevitable by-products of biological redox reactions and universal under stress situations. Reactive oxygen species inactivate enzymes and damage important cellular processes and subsequently cell components also. Plants and other organisms have evolved a wide range of mechanisms to contend with this problem by promoting the synthesis of ...

The seemingly disparate areas of oxygen toxicity, radiation exposure, and aging are now recognized to share a common feature-the aberrant production and/or removal of biologically derived free radicals and other reactive oxygen and nitrogen species (ROS/RNS). Advances in our understanding of the effects of free radicals in biology and medicine have been, and continue to be, actively translated ...

Endogenous and exogenous sources cause free radical-induced DNA damage in living organisms by a variety of mechanisms. The highly reactive hydroxyl radical reacts with the heterocyclic DNA bases and the sugar moiety near or at diffusion-controlled rates. Hydrated electron and H atom also add to the heterocyclic bases. These reactions lead to adduct radicals, further reactions of which yield num...

A role has been suggested for free radicals and active states of oxygen in tumor promotion. There are a number of lines of support for this hypothesis, but no definitive evidence. The hypothesis has proven of value in leading to the development of models pertinent to understanding the mechanism of action of tumor promoters.

Chromophore-assisted laser inactivation (CALI) is a technique that selectively inactivates proteins of interest to elucidate their in vivo functions. This method has application to a wide array of biological questions and an understanding of its mechanism is required for its judicious application. We report here that CALI is not mediated by photoinduced thermal denaturation but by photogenerate...

Kinetics of enzymic oxidation of indoleacetic acid (ISA) are interpreted as indicating that the reaction has an autocatalytic, cyclical mechanism invol\-ing unst,ablc intermcdiatcs whose formation and disappearance are important in determining the over-all reaction rate. The kinetics do not supporl the idea that IAA oxidation occurs mainly by reaction with Mnt3, nor that the reaction is an elec...

We recently published electron paramagnetic resonance (EPR) spin trapping results that demonstrated the enzymatic reduction of sulfur mustard sulfonium ions to carbon-based free radicals using an in vitro system containing sulfur mustard, cytochrome P450 reductase, NADPH, and the spin trap α-(4-pyridyl-1-oxide)-N-tert-butylnitrone (4-POBN) in buffer (A.A. Brimfield et al., 2009, Toxicol. Appl. ...