ACUTE BRAIN DAMAGE INDUCED BY X IRRADIATION WITH SPECIAL REFERENCE TO RATE AND RECOVERY FACTORS
Histopathologic studies were made of the brains of rats receiving limited head x irradiation of 3000 r delivered at the following dose rates: 930, 600, 300, and 150 r/min. No marked or consistent changes were revealed by physical examination before sacrifice or macroscopic analysis of gross brain after sacrifice at 1 to 48 postirradiation hours. Cerebellar granule cells demonstrated slight nuclear shrinkage and darkening of staining reaction (pyknosis). The severest response was elicited at the 930- and 600-r/min dose rates, becoming more pronounced from 1 to 24 hr after irradiation. At 48 hr, cerebellar granule cells were frequently normal or swollen in appearance and demonstrated a lighter stainlng reaction. Rossman-fixed material from animals that received 930- and 600-r/min dose rates demonstrated fine particulate granules of diastase-digestible periodic acidSchiff (PAS) positive material scattered throughout the neuropil with a tendency to greater concentration on the surfaces or in the vicinity of capillaries and small blood vessels. This phenomenon increased from the first to the 24 hr after irradiation and decreased thereafter. Acute swelling of oligodendroglia leading apparently to necrosis reached a maximum 6 to 24 hr after irradiation, irrespective of the dose rate. Numerical counts and statistical methods were employed to evaluate a quantitative and qualitative analysis of the data, but there were no consistent trends or significant changes among the various stages of oligodendroglial degeneration. There was no significant difference between the damaged oligodendrocytes of the brain stem and those of the cerebral cortex. There was a signlficant difference between the damaged oligodendrocytes of the cerebellum and those of both the brain stem and the cerebral cortex. In the cerebellum, there was a signlficant difference between the 0 dose rate (control) and the 300- 600-, and 930-r/min dose rates. There was also a signlficant difference between the 150-r/min dose rate and the 600- and 930-r/min dose rates. For the cerebral cortex, there was a signlficant difference between the 0 dose rate and the 150-, 300-, 600-, and 930- r/min dose rates. The same conclusion of the cerebral contex was made for the brain stem. Over-all analysis showed that the time and dose rate were significant at the 95% level. This effect is significant out of the third degree in time and the second degree in dose rate. However, it was concluded that effects of the dose rate in the range between 0 and 150 r/min requires further study. (BBB)
- Research Organization:
- Medical Coll. of Virginia, Richmond
- Sponsoring Organization:
- USDOE
- NSA Number:
- NSA-18-013520
- OSTI ID:
- 4083232
- Journal Information:
- Neurology (U.S.), Vol. Vol: 13; Other Information: Orig. Receipt Date: 31-DEC-64
- Country of Publication:
- Country unknown/Code not available
- Language:
- English
Similar Records
Locomotion, physical development, and brain myelination in rats treated with ionizing radiation in utero
RADIATION NECROSIS OF THE CEREBELLUM AFTER SINGLE, HIGH-DOSAGE X IRRADIATION