The enhanced sensitivity of mammalian cells to killing by x rays after prolonged exposure to several nitroimidazoles

Journal Article · Sun Feb 28 23:00:00 EST 1982 · Int. J. Radiat. Oncol., Biol. Phys.; (United States)

DOI:https://doi.org/10.1016/0360-3016(82)90658-7· OSTI ID:6715152

Hall, E J ^[1]; Astor, M; Biaglow, J; Parham, J C

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1. Columbia Univ. Coll. of Physicians and Surgeons, New York, NY

Electron affinic compounds, such as misonidazole, preferentially sensitize hypoxic cells to killing by X rays, and are also preferentially cytotoxic to cells deficient in oxygen. Prolonged exposure of cells to misonidazole prior to irradiation results in an increased radiosensitization. This is expressed as the Extra Enhancement Ratio (EER), defined as the ratio of the doses delivered immediately after the addition of the sensitizer or after prolonged incubation, that produce a given biological effect. Chinese hamster V79 cells have been used to investigate this prolonged incubation effect for a variety of 2-nitroimidazoles including misonidazole, desmethylmisonidazole and SR-2508 and as well as two ortho-substituted-4-nitroimidazoles with a bromine or sulfonamide group substitued in the 5-position. A considerable variation was observed in the magnitude of the Extra Enhancement Ratio (EER) produced by pre-incubation wth different compounds at concentrations that produce the same sensitizing effect. There is a good correlation between the EER and the measured rate at which the various sensitizers deplete cells of non-protein sulfhydryl compounds. There is also a good correlation between the EER and the fraction of cells killed by the pre-incubation period in the drug.

• OSTI ID: 6715152
• Journal Information: Int. J. Radiat. Oncol., Biol. Phys.; (United States), Journal Name: Int. J. Radiat. Oncol., Biol. Phys.; (United States) Vol. 8:3/4; ISSN IOBPD
• Country of Publication: United States
• Language: English

Related Subjects

560121* -- Radiation Effects on Cells-- External Source-- (-1987)
560301 -- Chemicals Metabolism & Toxicology-- Cells-- (-1987)
63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT.
ANIMAL CELLS
ANIMALS
ANOXIA
AZOLES
CELL CULTURES
CELL KILLING
CONNECTIVE TISSUE CELLS
ELECTROMAGNETIC RADIATION
FIBROBLASTS
HAMSTERS
HETEROCYCLIC COMPOUNDS
IMIDAZOLES
IONIZING RADIATIONS
MAMMALS
NITRO COMPOUNDS
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
ORGANIC SULFUR COMPOUNDS
RADIATIONS
RADIOINDUCTION
RADIOSENSITIVITY EFFECTS
RESPONSE MODIFYING FACTORS
RODENTS
SOMATIC CELLS
THIOLS
VERTEBRATES
X RADIATION