Kinetic basis for compensated hemopoiesis during continuous irradiation with low doses. [. gamma. rays; mice]
The hemopoietic effects of low-level continuous ..gamma.. irradiation with a daily regime of 16.0, 2.5, 1.4, and 1.15 rad were studied in mice. Irradiation time varied from 3 to 38 days. During the irradiation in vivo TL dosimetry was applied. Between 43 and 50 rad the reduction in both erythropoiesis and the number of femoral colony-forming cells (CFU/sub 8/) were inversely related to irradiation time. If exposure time was extended to over 30 days, /sup 59/Fe uptake and stem cell level practically agreed with those of the control indicating a compensation within the hemopoietic system. At the same time, however, a significantly increased proliferation rate of CFU/sub 8/ was found. The threshold dose for a detectable increase in CFU/sub 8/ turnover rate was observed to be about 30 rad at 2.5 rad daily dose. The results suggest the following conclusions. (1) In spite of the virtually unaltered hemopoiesis during the low-level chronic irradiation, characteristic changes can be detected in the turnover rate of the CFU/sub 8/ population. Therefore, the number of CFU/sub 8/ in S phase is proposed to be a suitable tool for the investigation of the effects of low-level irradiation. (2) The significantly enhanced proliferation rate of CFU/sub 8/ can be regarded as the basis for the maintenance of the normal stem cell level and hemopoiesis during low-level irradiation.
- Research Organization:
- National Research Inst. for Radiobiology and Radiohygiene, Budapest, Hungary
- OSTI ID:
- 6137816
- Journal Information:
- Radiat. Res.; (United States), Vol. 77:2
- Country of Publication:
- United States
- Language:
- English
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BLOOD FORMATION
BIOLOGICAL RADIATION EFFECTS
CFU
POPULATION DYNAMICS
ERYTHROPOIESIS
LOW DOSE IRRADIATION
RISK ASSESSMENT
STEM CELLS
ACUTE IRRADIATION
CHRONIC IRRADIATION
COBALT 60
COMPARATIVE EVALUATIONS
EXPERIMENTAL DATA
GAMMA RADIATION
ISOLATED VALUES
MICE
WHOLE-BODY IRRADIATION
ACUTE EXPOSURE
ANIMAL CELLS
ANIMALS
BETA DECAY RADIOISOTOPES
BETA-MINUS DECAY RADIOISOTOPES
BIOLOGICAL EFFECTS
CHRONIC EXPOSURE
COBALT ISOTOPES
DATA
DATA FORMS
ELECTROMAGNETIC RADIATION
EXTERNAL IRRADIATION
INFORMATION
INTERMEDIATE MASS NUCLEI
INTERNAL CONVERSION RADIOISOTOPES
IONIZING RADIATIONS
IRRADIATION
ISOMERIC TRANSITION ISOTOPES
ISOTOPES
MAMMALS
MINUTES LIVING RADIOISOTOPES
NUCLEI
NUMERICAL DATA
ODD-ODD NUCLEI
RADIATION EFFECTS
RADIATIONS
RADIOISOTOPES
RODENTS
SOMATIC CELLS
VERTEBRATES
YEARS LIVING RADIOISOTOPES
560152* - Radiation Effects on Animals- Animals