Sensitization of Anoxic Mammalian Cells to Radiation by Triacetoneamine-N-Oxyl. Effect of Pre- and Postirradiation Treatment

Agnew, D. A.; Skarsgard, L. D.

doi:10.2307/3573647

Cited by 18 publications

(3 citation statements)

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“…It has previously been suggested for Ehrlich ascites cells that the conversion of spin label into diamagnetic species, probably through reduction, might occur at the cell surface (31). An alternative explanation is that the radicals might penetrate into the cells and there undergo bioreduction (26)(27)(28)32). The chemical reaction in both cases might be mediated enzymat- ically.…”

Section: Resultsmentioning

confidence: 98%

“…Cellularly induced decay of spin labels has been previously investigated because it interferes with their function as radiosensitizers (26) and as cellular probes (27). Probably by metabolizing the free radicals, various cells or cellular components were reported to hasten the decay of ESR signals from stable nitroxides and spin adducts (26)(27)(28)(29)(30)(31).…”

Section: Resultsmentioning

confidence: 99%

“…The heating of the cells partially reduced the rate of the cellularly induced decay of the spin adduct but did not eliminate it. This implies that in addition to metabolic pathways by which it can be blocked as discussed (26)(27)(28)(29)(30)(31)(32), the spin adduct might be converted into an ESR-silent species via some nonenzymatic mechanism. Supporting this conclusion is the lack of protection by azide and the finding that cyanide provided only a small protective effect.…”

Section: Resultsmentioning

confidence: 99%

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On the spin trapping and ESR detection of oxygen-derived radicals generated inside cells.

Samuni¹,

Carmichael²,

Russo³

et al. 1986

Proc. Natl. Acad. Sci. U.S.A.

102

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Recently several attempts to identify oxygenderived radicals in whole cells by spin trapping and electron spin resonance have been reported by using 5,5-dimethyl-1-pyrroline-N-oxide as the spin trap. In the present study, the feasibility of this method is examined. Chinese hamster V79 cells and human erythrocytes served as the test systems, while OH radicals were generated by y radiolysis. Several spin traps were used to scavenge the radicals and a distinction between exo-and endocellular ESR observable species was achieved using tri(oxalato) chromiate(I) as a line broadening agent. To distinguish between exo-and endocellular sites of radical formation, we studied the effects of high molecular weight scavengers (polyethylene glycols), which do not enter the cell. Various possible obstacles associated with trapping and detecting the radicals inside the cells were examined. The results indicate that the primary radicals react with the spin traps. However, these spin adducts decayed within the cells.Cellularly induced decay of 2-hydroxy-5,5-dimethyl-1-pyrrolidinyloxyl radical presented the major difficulty in detecting the endogenous radicals, and potential experimental approaches to overcome this difficulty are discussed.Oxygen-derived radicals in various biological systems under physiological conditions have been identified by using spintrapping and electron spin resonance (ESR) spectrometry mainly in solutions or in in vitro systems containing subcellular components as with tissue homogenates (1)(2)(3) Chemicals. a-Phenyl-N-tert-butylnitrone (PBN), a-(4-pyridyl-1-oxide)-N-tert-butylnitrone (4-POBN), 5,5-dimethyl-1-pyrroline-N-oxide (DMPO), a-(4-N-methylpyridinium-Ntert-butylnitrone (PyBN), and the stable nitroxide 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO) were purchased from Aldrich. Polyethylene glycols (PEG) Abbreviations: PBN, a-phenyl-N-tert-butylnitrone; 4-POBN, a-(4-pyridyl-1-oxide)-N-tert-butylnitrone; DMPO, 5,5-dimethyl-1-pyrroline-N-oxide; PyBN, a-(4-N-methylpyridinium)-N-tert-butylnitrone; TEMPO, 2,2,6,6-tetramethylpiperidine-1-oxyl; Me2SO, dimethyl sulfoxide.

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Section: Resultsmentioning

confidence: 98%

Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

See 1 more Smart Citation

On the spin trapping and ESR detection of oxygen-derived radicals generated inside cells.

Samuni¹,

Carmichael²,

Russo³

et al. 1986

Proc. Natl. Acad. Sci. U.S.A.

102

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Effects of Ionizing Radiation on Mammalian Cells

Little

Williams

1977

Comprehensive Physiology

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The sections in this article are: Physical and Chemical Events Development of Radiation Injury The Target Theory Direct and Indirect Effects, Radiation Chemistry Effects on Cell Division Division Delay Mitotic Inhibition (Reproductive Failure) Radiation Sensitivity in Different Phases of the Life Cycle Chromosomal Damage Interphase Death Nonlethal Heritable Changes Biological Variation in Radiation Sensitivity Mechanisms Modification of Radiation Effects Physical Factors Chemical Radiation Protection and Sensitization Oxygen Effect Intracellular Recovery Processes Repair of Potentially Lethal Damage Repair of Sublethal Damage (Split‐Dose Recovery) Molecular Repair Processes Damage Observed in DNA Cellular Repair Systems for DNA Damage Repair Activities in Mammalian Cells Correlation of DNA Repair with Biological Effects Concluding Remarks Addendum

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From Nitric Oxide to Desferal: Nitrogen Free Radicals and Iron in Oxidative Injury

Willson

1988

Oxygen Radicals in Biology and Medicine

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Sensitization of Anoxic Mammalian Cells to Radiation by Triacetoneamine-N-Oxyl. Effect of Pre- and Postirradiation Treatment

Cited by 18 publications

References 4 publications

On the spin trapping and ESR detection of oxygen-derived radicals generated inside cells.

On the spin trapping and ESR detection of oxygen-derived radicals generated inside cells.

Effects of Ionizing Radiation on Mammalian Cells

From Nitric Oxide to Desferal: Nitrogen Free Radicals and Iron in Oxidative Injury

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