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Brain nitric oxide synthase (NOS), which utilizes NADPH and calcium/calmodulin as cofactors for metabolizing L-arginine to nitric oxide (NO) and L-citrulline, contains recognition sites for the flavins FAD and FMN. Using a spin-trapping technique combined with electron spin resonance spectroscopy, we report that brain NOS generates superoxide O2-. in a(More)
Neuronal nitric-oxide synthase (NOS I) in the absence of L-arginine has previously been shown to generate superoxide (O-2) (Pou, S., Pou, W. S., Bredt, D. S., Snyder, S. H., and Rosen, G. M. (1992) J. Biol. Chem. 267, 24173-24176). In the presence of L-arginine, NOS I produces nitric oxide (NO.). Yet the competition between O2 and L-arginine for electrons,(More)
Biologically generated nitric oxide appears to play a pivotal role in the control of a diverse series of physiologic functions. Iron-chelates and low-frequency EPR spectroscopy have been used to verify in vivo production of nitric oxide. The interpretation of in vivo identification of nitric oxide localized at the site of evolution in real time is(More)
Nitric-oxide synthases (NOS, 1 EC are hemeproteins that catalyze oxidation of L-arginine to NO ⅐ and L-citrulline. Three main isozymes exist in mammals that are regulated by distinct genes (1– 6): a constitutive neuronal NOS (nNOS or NOS I), (7, 8), an endotoxin-and cytokine-inducible NOS (iNOS or NOS II) (9, 10), and a constitutive endothelial(More)
Using the electron spin resonance/spin trapping system, 4-pyridyl 1-oxide N-tert-butylnitrone (4-POBN)/ethanol, hydroxyl radical was detected as the alpha-hydroxyethyl spin trapped adduct of 4-POBN, 4-POBN-CH(CH3)OH, from phorbol 12-myristate 13-acetate-stimulated human neutrophils and monocytes without the addition of supplemental iron. 4-POBN-CH(CH3)OH(More)
Phagocytes mediate their innate immunological response by releasing products that damage invading microorganisms. These products include proteins such as lysozyme, peroxidases, and elastase as well as reactive oxygen species such as superoxide, hydrogen peroxide, hypohalous acid, and hydroxyl radical. Although it is clear that many phagocytic secretory(More)
The spin trap 5,5-dimethyl-1-pyrroline-1-oxide (DMPO) alone, as well as DMPO or N-tert-butyl-alpha-phenylnitrone (PBN) in the presence of excess dimethyl sulfoxide (Me2SO), have been used as spin trapping systems for the detection of hydroxyl radical. However, the instability of DMPO and many of its corresponding spin-trapped adducts has limited the(More)
OBJECTIVE AND DESIGN Effects of activated PMN on airway goblet cell mucin release were investigated using a co-culture system in which both tracheal surface epithelial (TSE) cells and PMN from hamsters were present. MATERIALS AND METHODS TSE cells were metabolically labeled using (3)H-glucosamine and chased in the presence of PMN under various(More)
With an eye toward the development of nitroxides as potential contrast enhancing agents for MRI applications, we have compared the rates of reduction of 24 nitroxides of diverse structures by rat whole liver homogenate, hepatocytes, subcellular fractions, and ascorbate (10 eq excess). Our results indicate that five-membered ring nitroxides and alpha-carboxy(More)
The reaction of xanthine and xanthine oxidase generates superoxide and hydrogen peroxide. In contrast to earlier works, recent spin trapping data (Kuppusamy, P., and Zweier, J.L. (1989) J. Biol. Chem. 264, 9880-9884) suggested that hydroxyl radical may also be a product of this reaction. Determining if hydroxyl radical results directly from the(More)