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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)
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)
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)
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)
Nitric-oxide synthases (NOS, EC 1.14.13.39) are hemeproteins that catalyze oxidation of L-arginine to NOz 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 endotoxinand cytokine-inducible NOS (iNOS or NOS II) (9, 10), and a constitutive endothelial NOS(More)
Toward the development of a fluorescence assay in combination with confocal microscopy to image free radicals generated by cells, we synthesized a fluorophore-nitroxide, 5-((2-carboxy)phenyl)-5-hydroxy-1-((2,2,5,5-tetramethyl-1-oxypyrrolid in-3- yl)methyl)-3-phenyl-2-pyrrolin-4-one sodium salt, and tested the applicability of this probe to detect(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)
Age-related macular degeneration (ARMD) is one of the leading causes of severe visual loss in the United States. Numerous risk factors have been investigated, but the pathogenesis of ARMD has remained elusive. The authors propose that ARMD develops as a direct result of photosensitization of the vascular endothelium of the choriocapillaris, Bruch's(More)
Brain sigma-type receptors are thought to mediate hallucinogenic effects of certain benzomorphan opiates in humans. The biochemical characterization of sigma receptors has been difficult because of the lack of potent and selective ligands. We report here the synthesis and characterization of a tritiated, symmetrically substituted guanidine derivative,(More)
Exposure of cultured Chinese hamster ovary (CHO) cells to hydrogen peroxide results in the production of extensive DNA breakage which can be prevented by the intracellular calcium chelator Quin 2. This effect occurs at Quin 2 AM concentrations as low as 0.1 microM and is maximal at 1 microM. Addition of the extracellular calcium chelator, EGTA, does not(More)