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BACKGROUND N-acetylcysteine (NAC) has been in clinical practice for several decades. It has been used as a mucolytic agent and for the treatment of numerous disorders including paracetamol intoxication, doxorubicin cardiotoxicity, ischemia-reperfusion cardiac injury, acute respiratory distress syndrome, bronchitis, chemotherapy-induced toxicity, HIV/AIDS,(More)
Changes in chromatin composition accompany cellular differentiation in eukaryotes. Although bulk chromatin is duplicated during DNA replication, replication-independent (RI) nucleosome replacement occurs in transcriptionally active chromatin and during specific developmental transitions where the genome is repackaged. In most animals, replacement uses the(More)
We report here a novel cDNA clone with a predicted protein sequence similar to lysyl oxidase. This full-length cDNA clone of 3432 base pairs (WS9-14) was isolated from human fibroblasts on the basis of its overexpression in senescent cells. It encodes an 87-kDa polypeptide, whose protein is a member of the scavenger receptor cysteine-rich family, because it(More)
Nitronyl nitroxides, such as derivatives of 2-phenyl-4,4,5,5,-tetramethylimidazoline-1-oxyl 3-oxide (PTIOs), react with *NO to form the corresponding imino nitroxides (PTIs) and *NO2. PTIOs are considered as monitors of *NO, stoichiometric sources of *NO2, biochemical and physiological effectors, specific tools for the elimination of *NO, and potential(More)
In this study we calculate the half-life of .NO in its reactions with superoxide and with oxygen under various conditions using the known rate constants for these reactions. The measured half-life of .NO in biological systems is 3-5 s, which agrees well with the calculated value for intracellular .NO, but not for extracellular .NO under normal physiological(More)
Stable nitroxide radicals were reported to act as SOD mimics and catalyze the dismutation of O2-. through two different catalytic pathways including reductive and oxidative reaction mechanisms (Samuni, A., Krishna, C. M., Riesz, P., Finkelstein, E. & Russo, A. (1988) J. Biol Chem. 263, 17921-17924). Recent studies directly monitoring O2-. and employing(More)
The reactions of NO. with O2.- and with HO2. were studied using the pulse radiolysis technique under pseudo first order conditions where ([O2.-]o + [HO2.]o) > [NO.]o at pH 3.3-10.0. The rate constant of the reaction of NO. with O2.- was determined both by monitoring the decay of O2.- at 250 nm and the formation of ONOO- at 302 nm to be (4.3 +/- 0.5) x 10(9)(More)
Nitroxide stable radicals generally serve for probing molecular motion in membranes and whole cells, transmembrane potential, intracellular oxygen and pH, and are tested as contrast agents for magnetic resonance imaging. Recently nitroxides were found to protect against oxidative stress. Unlike most low molecular weight antioxidants (LMWA) which are(More)
Nitroxide antioxidants can be reduced to hydroxylamines or oxidized to oxoammonium cations. Consequently, nitroxides can modify oxidative damage acting as reducing and/or as oxidizing agents, and in many cases the nitroxides are continuously recycled. They provide protection against oxidative stress via various mechanisms including SOD-mimic activity and(More)