Dark-field Observations on Lymphocytes Exposed to X-Rays and Injurious Agents.

Abstract

Suspensions from the rabbit thymus were treated with x-rays (1000r), incubated at 37[degree] and were examined by dark-field illumination, by histo-logic sections and by the method of unstained cell counts. In irradiated suspensions incubated for 3 hrs., many of the cells had, on dark-field examination, one or more primary vacuoles usually surrounded by a bright vacuolar. wall. On histologic section, these vacuoles were seen to be intranuclear and acidophilic. In irradiated suspensions incubated for 24 hrs., most of the cells had a single relatively large secondary vacuole and a crescent of fine and coarse granules. On histologic examination, the secondary vacuole was seen to be a pyknotic nucleus. According to the method of unstained cell count, the cells with primary vacuoles were viable and the cells with secondary vacuoles were dead. Non-irradiated suspensions incubated for 24-48 hrs. also developed primary and secondary vacuoles but at a much lower rate than in the irradiated suspensions. Irradiation of the rat thymus in vivo also resulted in cells with primary and secondary vacuoles. Thymic cells incubated at 45[degree] developed coarse granules but not vacuoles. The addition of distilled water to lymphocytes produced enlargement and vacuolization of the nuclei. The hypothesis is proposed that irradiation caused the absorption of water into one or more foci in the nucleus and caused the acceleration of a normal physiologic and degenerative process in the lymphocyte.