Previous studies by time-lapse cinemicrography (1) showed that irradiated lymphocytes, after a latent period, undergo lobulation and death. This work has been repeated with the use of a new cinemicrographic apparatus which provided additional information in regard to the morphology and death of irradiated and non-irradiated lymphocytes. Methods: A cell suspension was prepared from the thymus of a rabbit by methods described in another paper (2). The cells were suspended in 50 per cent rabbit serum and treated with 1,000 r from a 200-kv machine. A drop of the irradiated and non-irradiated suspension was placed between two cover slips, separated by a metal disk 0.8 mm. in thickness. The preparation was incubated at 37° C. and photographed. The cinemicrographic outfit consisted of an inverted microscope equipped with a fluorite, phase-contrast, oil-immersion objective 45×, N.A. 0.95. The microscope was enclosed in a Lucite incubator which maintained a temperature of 37° C. A 16-mm. moving picture camera with time-lapse equipment was mounted in front of the microscope. Pictures were taken on negative film at the rate of 1 frame per two to six seconds. The magnification on the film was 170×. Projection of the cinemicrographic film at the normal speed of 16 frames per second did not permit a detailed study of the film. It was necessary to project at lower speeds and to view and print many single frames. A commercial moving picture projector with a hand drive and a counter to enumerate the individual frames was used to study the film. A voltage transformer was inserted in the electric circuit of the lamp so that the light could be controlled to minimize heat and to facilitate printing. The positive film was studied carefully, and the frames needed for printing were determined and identified by means of the counter. The negative film was then run through and the image was projected downward by means of a first surfaced mirror at a 45° angle. By this means 3 × 4-inch prints were made from the 16-mm. film. The final magnification was then 1,750×. Results Irradiated Lymphocytes: On the projected cinemicrographic film the irradiated lymphocytes at first seemed normal in appearance and in behavior. Figure 1 shows still prints of two morphologically normal cells labeled E and F and gives the duration of incubation in hours and minutes. It is seen from the figure that the lymphocytes had large, round or oval nuclei with distinct nuclear walls. Several large dark granules are visible beneath the nuclear membrane and in the interior of the nucleus. The granules are apparently chromatin in character, as indicated by their distribution, number, and size. A small amount of cytoplasm is seen in cell F, which is undergoing ameboid motion. The light halo around the cells is an artefact produced by the phase microscopy. On projection of the time-lapse cinemicrographic film, the viable lymphocytes had an active rhythmic, vibratory, brownian-like movement.
No takes yet. Share an insight, caveat, or question.
Robert Schrèk (1955) studied this question.