. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. 92 PATRICIA J. HARRIS. CAST LEAD END WINDOW C-M TUBE UEAD SHIELD SCAU&P. J FIGURE 1. Counter arrangement for measuring activity of thyroid area. Skokie, 111.). Lead shielding was found to be necessary around the tube, and its photosensitivity was obviated by cementing a thin plastic film over the opening in the bottom of the block and coating with "Aquadag" (see Fig. 1). A series of trial injections of I131 indicated that a dose of yu,C per five-gram fish gave an adequate counting rate, and since this was a
. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. 92 PATRICIA J. HARRIS. CAST LEAD END WINDOW C-M TUBE UEAD SHIELD SCAU&P. J FIGURE 1. Counter arrangement for measuring activity of thyroid area. Skokie, 111.). Lead shielding was found to be necessary around the tube, and its photosensitivity was obviated by cementing a thin plastic film over the opening in the bottom of the block and coating with "Aquadag" (see Fig. 1). A series of trial injections of I131 indicated that a dose of yu,C per five-gram fish gave an adequate counting rate, and since this was also in line with tracer doses used by Gorbman and Berg (1955) and others, it was subsequently used in this screening procedure. RESULTS Histological studies of the thyroid Following fixation in Bouin's solution at the time of autopsy, the thyroid regions of the experimental and control fish were examined histologically to determine the degree of thyroidectomy. Serial sections were made through the entire region, and an evaluation was made based on the relative number of follicles present, the height of the epithelial cells, and amount of colloid, in relation to the control fish. Few of the treated fish showed a total lack of follicles, but it was interesting to note that these fish, and others with very few follicles, did not survive to the end of the experiment. There was a great range in the amount of thyroid tissue present. However, while some fish showed evidence of considerable regeneration, in the majority of fish regeneration was present to a much lesser extent, and on the whole they could be considered markedly hypothyroid. Uptake of a tracer dose of 7131 in hypothyroid and control fish The most promising means of evaluating the tracer data appeared to be a simple comparison of rate of activity loss in the thyroid region of the treated (hypothyroid). Please note that these images are extracted from scanned page images that may have been digitally enhanced for readabilit
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Keywords: ., bookauthorlilliefrankrat, booksubjectbiology, booksubjectzoology
