Spin trapping evidence for the lack of significant hydroxyl radical production during the respiration burst of human phagocytes using a spin adduct resistant to superoxide-mediated destruction
- Veterans Administration Medical Center, Iowa City, IA (USA)
Failure to detect hydroxyl radical (.OH)-derived spin adducts of 5,5-dimethyl-1-pyrroline N-oxide in electron spin resonance (ESR) spin trapping experiments has been offered as evidence for the lack of the endogenous capacity of stimulated human phagocytes neutrophils, monocytes, and monocyte-derived macrophages (MDM) to generate .OH. Recent reports that 5,5-dimethyl-1-pyrroline N-oxide spin adducts are unstable in the presence of superoxide-generating systems such as stimulated neutrophils has raised concerns regarding the sensitivity of spin trapping techniques for assessment of phagocyte free radical formation. Consequently, we have employed a new approach that uses the spin trap N-t-butyl-alpha-phenyl-nitrone (PBN) and dimethyl sulfoxide. In the presence of dimethyl sulfoxide and PBN, the formation of .OH via three different mechanisms in air-saturated aqueous solutions all yielded a single nitroxide species whose ESR peak amplitude remained stable in the presence of superoxide (.O2-). This nitroxide, which we have assigned as PBN/.OCH3, appears to be an oxygen-centered radical derived from the spin trapping of the reaction product of O2 and methyl radical. When neutrophils, monocytes, or MDM were stimulated with phorbol 12-myristate 13-acetate or opsonized zymosan in the presence of exogenous iron, catalase-inhibitable PBN/.OCH3 was the sole nitroxide detected. In the absence of exogenous iron, no nitroxide was observed, providing evidence for the lack of the endogenous capacity of neutrophils, monocytes, and MDM to generate .OH.
- OSTI ID:
- 7024912
- Journal Information:
- Journal of Biological Chemistry; (USA), Journal Name: Journal of Biological Chemistry; (USA) Vol. 265:5; ISSN JBCHA; ISSN 0021-9258
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT.
ANIMAL CELLS
AQUEOUS SOLUTIONS
BIOLOGICAL EFFECTS
BIOLOGICAL MATERIALS
BIOSYNTHESIS
BLOOD
BLOOD CELLS
BODY FLUIDS
CARCINOGENS
CHALCOGENIDES
CONNECTIVE TISSUE CELLS
DISPERSIONS
ELECTRON SPIN RESONANCE
ELEMENTS
ESTERS
HYDROXYL RADICALS
IN VITRO
LEUKOCYTES
MACROPHAGES
MAGNETIC RESONANCE
MATERIALS
MIXTURES
MONOCYTES
NEUTROPHILS
NITROGEN COMPOUNDS
NITROGEN OXIDES
NONMETALS
ORGANIC COMPOUNDS
OXIDES
OXYGEN
OXYGEN COMPOUNDS
PHAGOCYTES
PHORBOL ESTERS
RADICALS
RESONANCE
SOLUTIONS
SOMATIC CELLS
SUPEROXIDE RADICALS
SYNTHESIS