Quantitative Histologic and Behavioral 



Studies on Effects of Fetal X-lrradiation in 



Developing Cerebral Cortex of White Rat * 



K. R. Brizzee. L. a. Jacobs. X. Kharetchko. and J. C". Sharp 



University of Utah College of Medicine, 

 Salt Lake City, Utah 



Introduction 



Recent experimental studies on effects of fetal irradiation on nervous tis- 

 sues have clearly showns (Hicks, 1954. and Hicks it al., 1957 i that primiti\e 

 neuroblasts and spongioblasts are selecti\ely damaged by ionizing i adiation. It 

 has also been demonstrated in this work that rather specific and predictable 

 anomalies are produced in nervous tissues in postnatal life in the rat by radia- 

 tion exposure on any given day in the gestation period between the 9th day and 

 birth. At the same time, some beha\ioral studies i Levinson. 1952: Furchtgott 

 and Echols. 1958a. bi have demonstrated serious beha\ioral deficits in rats 

 irradiated as fetuses. While considerable attention has been given in the 

 histopathologic studies to the regenerati\e ability and reco\ery of nervous 

 tissues from such radiation exposure (Hicks. 1957) little effort has been 

 devoted to analyzing the capacity of the cells sur\iving irradiation exposure 

 for normal growth or the specific effects of the irradiation on cell growth. 

 Further, the behavioral studies carried out thus far have not emphasized 

 the possible relationships between cytologic deficits and beha\ ioral deficits. It 

 has been our purpose, therefore, in initiating the present series of investiga- 

 tions to analyze effects of fetal x-irradiation administered in fractionated 

 and single doses on early postnatal growth of sur\i\ing cells in cerebral 

 cortex and to determine what relationships may exist between alterations in 

 normal growth patterns or cytologic deficits and beha\ioral abnormalities 

 appearing later in life. The present report is concerned with our preliminan- 

 findings with fractionated doses administered during the latter half of the 

 testation jx-riod. 



* Supported in part by research grants from the National Institute of Neurological 

 Diseases and Blindness. National Institutes of Health, and the University of Utah 

 Research Fund. 



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