EFFECTS OF HEAVY HIGH-ENERGY CHARGED PARTICLES. II. PRIMARY ATYPICAL EPITHELIAL HYPERPLASIA IN MOUSE SKIN AFTER EXPOSURE TO 10-Mev PROTONS, 20-Mev DEUTERONS, OR 30-Mev /cap alpha/-PARTICLES
The direct effect of ionizing radiation upon mouse epidermis was investigated by using an external beam of these accelerator-produced monoenergetic, heavy ionizing particles. These particles have a finite, energy- dependent range of penetration in tissue. Ionization occurs throughout the entire path of the particles with a final rise to a peak (Bragg peak) just before the end of the path is reached, By introduction of a rotating disc filter of varying thickness in the form of a wheel revolving in front of the radiation pont it was possible to deliver a series of Bragg peaks. In this way a cylinder of skin was irradiated with resultant nearly uniform ionization limited to a total depth of 1 to 2 mm, depending upon the particle and energy selected for the experiment. This approach is important, since apparently cellular damage in irradiated tissue depends not only upon the number of ions absorbed in a given volume of tissue but also upon the density of ionization. The gross appearance of the postirradiated skin areas was similar for all three types of panticles employed at 2000 to 5000 rad. Up to two days no obvious alteration was noted, but by the 3rd to 4th day the exposed areas were erythematous. By 6 to 7 days, the skin was thickened and indurated with superficial desquamation and epilation, A thin, dry eschar formed by the 10th to 14th day, with progressive contractive. After 25 to 30 days the irradiated areas were shiny and elevated, measuring from 5 to 8 mm in dia. After an exposure to 1200 rad of protons, at three days there was no microscopic alteration in the epidermis except alteration of some hair follicles. At 7 days the epidermis showed an increase in the width due to increase in the size and number of epithelial cells together with hyperkeratosis. Large vacuolnted nuclei with big nucleoli were in evidence. No changes were seen in the capillaries or arterioles. By the tenth day the width of the epidermis had increased further, and as many as 4 to 5 layers of epithelial cells were observed. At 20 days epithelial hyperplasia was marked. After exposure to 2000 and 5000 rad of deuterons, protons, or alpha panticles the epithelial hyperplastic changes appeared earlier and were more pronounced. In some instances the epidermal lesions resulting from an exposure of 2000 to 5000 rad resembled the type of lesion considered in the skin of man to be carcinoma in situ. Changes in underlying blood vessels and collagen were slight. (BBB)
- Research Organization:
- Bowman Gray School of Medicine, Winston-Salem, N.C.
- NSA Number:
- NSA-18-015827
- OSTI ID:
- 4070406
- Journal Information:
- Archives of Pathology (U.S.) Formerly Arch. Pathol. Lab. Med. Formerly AMA Arch. Pathol. Changed back to Arch. Pathol. Lab. Med., Vol. Vol: 76; Other Information: Orig. Receipt Date: 31-DEC-64
- Country of Publication:
- Country unknown/Code not available
- Language:
- English
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