Doctoral Dissertations

Date of Award

8-1972

Degree Type

Dissertation

Degree Name

Doctor of Philosophy

Major

Biomedical Engineering

Major Professor

William L. Russell

Committee Members

R. C. Fuller, E. F. Oakberg, E. H. Grell, L. B. Russell

Abstract

The specific-locus mutation frequency resulting from 300 R of acute X irradiation has been determined for the germ cells present in male mice at 0, 2, 4, 6, 8, 10, 14, 21, 28, and 35 days of age and also for female mice at 0 days of age, Sample size was much larger for the males irradiated on day 0 than for other age groups but in all groups it was large enough to insure that an extremely high rate would be noticed. At 35 days of age the testis is histologically similar to that of the adult. It was important to know if the germ cells present in immature mice yield the same mutation frequency as those in the adult.

The mutation frequency is only 1/2 as high in the day-0 male as it is in the similarly irradiated adult male, this difference being statistically significant. Taken together, the remaining nine groups of males have an average mutation frequency similar to that of the adult. None of the nine groups has a mutation rate statistically significantly higher than the adult.

There is a statistically significantly higher incidence of both permanent sterility and clusters of mutations following irradiation of day-0 males than is found for similarly irradiated adults. Both of these results would be expected if there are relatively fewer surviving germ cells following irradiation of the day-0 testis.

The mutation frequency per R is only 1/5 as high for the females irradiated with 300 R on day 0 as it is for adult females exposed to 400 R, the nearest dose used, this difference in rate being highly statistically significant. The reproductive capacity of the females irradiated on day 0 is about 1/3 that of control females,

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