The Reaction of the Skin Epithelium of the Tails of Rana catesbiana Tadpoles to Local X-Irradiation

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Abstract
One hundred tadpoles of Rana catesbiana were divided into 2 groups. In the 1st group, the tails were amputated and irradiated with 2000 to 4000 r after formation of tail regenerates. In the 2d group, the tails were irradiated with the same doses, but without amputation. The formation of degenerating giant cell epithelium was observed in both groups, but much more often in the group irradiated after formation of tail regenerates. In this group the giant cell epithelium was observed in about 80% of all cases. In the 2d group (irradiation without amputation) this epithelium was observed in only 33% of the cases. The typical giant cell epithelium consists of very large cells with large nucleus and nucleolus. Some cells are multinucleate. The general thickness of this epithelium is much greater than in control animals, the outer surface is very uneven and irregular, and separation of cells and outer groups of cells is typical. In some cases between the portions of degenerating giant cell epithelium in the distal region and in all proximal irradiated regions the formation of unusually large outgrowths was observed. These formations consisted of cells of normal size, with many mitotic figures. This is an example of indirect roentgen stimulation. The development of stimulated epithelium formations was observed in close proximity to the degenerated giant cell epithelium. Probably, the stimulation is the result of formation of some disintegration products ("necrohormones") in the neighboring degenerating portions of the epithelium.