Biomaterial Database

Reversed dose-rate effect and RBE of 252-californium radiation in the induction of 6-thioguanine-resistant mutations in mouse L5178Y cells. 1988

N Nakamura, and S Sawada

Department of Radiation Biology, Hiroshima University, Japan.

The effects of californium-252 radiation (average neutron energy E = 2.13 MeV) were investigated using mouse leukemia L5178Y cells. No dose-rate effect was detected for cell killing, but a 'reversed' dose-rate effect was observed for mutation induction. The frequency of 6-thioguanine-resistant mutations increased linearly up to 100 cGy (1 Gy = 100 rad), then began to level off at a dose rate of 1.2 cGy/min, while it increased continuously up to 200 cGy at a reduced dose rate of 0.16 cGy/min. Compared with results obtained using 60Co gamma-rays, the ratio of the initial slope of each dose-response curve was 4-5 for cell killing, and more than 11 for mutagenesis. Since one-third of 252Cf radiation consists of gamma-rays, the relative biological effectiveness (RBE) of 252Cf neutrons would be even greater, 16 or more, for mutation induction in the present assay.

UI	MeSH Term	Description	Entries
D007940	Leukemia L5178	An experimental lymphocytic leukemia of mice.	Lymphoma L5178,L5178, Leukemia,L5178, Lymphoma
D007942	Leukemia, Experimental	Leukemia induced experimentally in animals by exposure to leukemogenic agents, such as VIRUSES; RADIATION; or by TRANSPLANTATION of leukemic tissues.	Experimental Leukemia,Experimental Leukemias,Leukemia Model, Animal,Leukemias, Experimental,Animal Leukemia Model,Animal Leukemia Models,Leukemia Models, Animal
D009154	Mutation	Any detectable and heritable change in the genetic material that causes a change in the GENOTYPE and which is transmitted to daughter cells and to succeeding generations.	Mutations
D009502	Neutrons	Electrically neutral elementary particles found in all atomic nuclei except light hydrogen; the mass is equal to that of the proton and electron combined and they are unstable when isolated from the nucleus, undergoing beta decay. Slow, thermal, epithermal, and fast neutrons refer to the energy levels with which the neutrons are ejected from heavier nuclei during their decay.	Neutron
D012062	Relative Biological Effectiveness	The ratio of radiation dosages required to produce identical change based on a formula comparing other types of radiation with that of gamma or roentgen rays.	Biological Effectiveness, Relative,Effectiveness, Biologic Relative,Effectiveness, Biological Relative,Relative Biologic Effectiveness,Biologic Effectiveness, Relative,Biologic Relative Effectiveness,Biological Relative Effectiveness,Effectiveness, Relative Biologic,Effectiveness, Relative Biological,Relative Effectiveness, Biologic
D002142	Californium	A man-made radioactive actinide with atomic symbol Cf, atomic number 98, and atomic weight 251. Its valence can be +2 or +3. Californium has medical use as a radiation source for radiotherapy.
D002470	Cell Survival	The span of viability of a cell characterized by the capacity to perform certain functions such as metabolism, growth, reproduction, some form of responsiveness, and adaptability.	Cell Viability,Cell Viabilities,Survival, Cell,Viabilities, Cell,Viability, Cell
D003037	Cobalt Radioisotopes	Unstable isotopes of cobalt that decay or disintegrate emitting radiation. Co atoms with atomic weights of 54-64, except 59, are radioactive cobalt isotopes.	Radioisotopes, Cobalt
D004307	Dose-Response Relationship, Radiation	The relationship between the dose of administered radiation and the response of the organism or tissue to the radiation.	Dose Response Relationship, Radiation,Dose-Response Relationships, Radiation,Radiation Dose-Response Relationship,Radiation Dose-Response Relationships,Relationship, Radiation Dose-Response,Relationships, Radiation Dose-Response
D004351	Drug Resistance	Diminished or failed response of an organism, disease or tissue to the intended effectiveness of a chemical or drug. It should be differentiated from DRUG TOLERANCE which is the progressive diminution of the susceptibility of a human or animal to the effects of a drug, as a result of continued administration.	Resistance, Drug