Discrepancies between patterns of potentially lethal damage repair in the RIF-1 tumor system in vitro and in vivo
Repair of potentially lethal damage (PLD) was studied in the RIF-1 tumor system in several different growth states in vivo. Exponentially growing, fed plateau, and unfed plateau cells in cell culture as well as small and large subcutaneous or intramuscular tumors were investigated. Large single doses of radiation followed by variable repair times as well as graded doses of radiation to generate survival curves immediately after irradiation or after full repair were investigated. All repair-promoting conditions studied in vitro (delayed subculture, exposure of cells to depleted growth medium after irradiation) increased surviving fraction after a single dose. The D/sub 0/ of the cell survival curve was also increased by these procedures. No PLD repair was observed for any tumors irradiated in vivo and maintained in the animal for varying times prior to assay in vitro. The nearly 100% cell yield obtained when this tumor is prepared as a single-cell suspension for colony formation, the representative cell sample obtained, and the constant cell yield per gram as a function of time postirradiation suggest that this discrepancy is not an artifact of the assay system. The most logical explanation of these data and information on radiocurability of this neoplasm is that PLD repair, which is so frequently demonstrated in vitro, may not be a major factor in the radioresponse of this tumor when left in situ.
- Research Organization:
- Univ. of Washington School of Medicine, Seattle
- OSTI ID:
- 5682725
- Journal Information:
- Radiat. Res.; (United States), Journal Name: Radiat. Res.; (United States) Vol. 93:1; ISSN RAREA
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
560152 -- Radiation Effects on Animals-- Animals
63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT.
ALKALI METAL ISOTOPES
ANIMAL CELLS
BETA DECAY RADIOISOTOPES
BETA-MINUS DECAY RADIOISOTOPES
BIOLOGICAL RECOVERY
BIOLOGICAL REPAIR
CELL KILLING
CESIUM 137
CESIUM ISOTOPES
DATA
ELECTROMAGNETIC RADIATION
EXPERIMENTAL DATA
EXPERIMENTAL NEOPLASMS
GAMMA RADIATION
IN VITRO
IN VIVO
INFORMATION
IONIZING RADIATIONS
ISOTOPES
NUCLEI
NUMERICAL DATA
ODD-EVEN NUCLEI
RADIATIONS
RADIOINDUCTION
RADIOISOTOPES
RECOVERY
REPAIR
SURVIVAL CURVES
TUMOR CELLS
YEARS LIVING RADIOISOTOPES