A MEASURE OF ACUTE RECOVERY AND OF RESIDUAL RADIATION INJURY TO ERYTHROPOIETIC SYSTEM OF RATS GIVEN REPETITIVE X-RAY EXPOSURES
Rats exposed repeatedly to 300 r x rays show a decrease in Fe/sup 59/ incorporation which attains its lowest point 48 hours post-irradiation. Thereafter iron uptake increases until normal values are measured. This return to normalcy is delayed further with each newly repeated irradiation. On any day during the recovery pericd Fe/sup 59/ uptake decreases exponentially with repeated x irradiations. The decrease is a measure of residual injury to the erythropoietic system. Since it was demonstrated that after each repeated irradiation a reduced amount of Fe/sup 59/ was incorporated into newly formed erythrocytes at the beginning of the recovery period while the rate of recovery is similar, it is postulated that the decrease in Fe/sup 59/ uptake is due to a decrease in the functional capacity of the stem cells to proliferate erythrocytes. A working hypothesis for the calculation of erythrocyte stem cell damage was presented. This calculation indicates that only 77 to 80% of the previously measured amount of erythrocyte precursors were present after each repeated x-ray exposure. bed cell mass and hematocrit values measured after the animals had recovered from the effects of irradiation indicate that despite the reduction in the functional capacity of the stem cells to proliferate erythrocytes, the daily red cell turnover is nearly normal. The data indicate that only when this is reduced below a certain limit does a permanent anemia ensue. (auth)
- Research Organization:
- Naval Radiological Defense Lab., San Francisco
- NSA Number:
- NSA-14-022757
- OSTI ID:
- 4154298
- Report Number(s):
- USNRDL-TR-432
- Country of Publication:
- Country unknown/Code not available
- Language:
- English
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