Letter | Published:

Estimation of Time of Generation of Living Cells

Naturevolume 191pages290291 (1961) | Download Citation



THE use of tritiated thymidine as a labelling agent has greatly facilitated examination of nuclear reproduction and cellular proliferation1–4. In such work, it has been customary to focus attention on the proliferation and fate of the cells that are labelled. Mendelsohn, however, has studied the fate of both labelled and unlabelled cells in tumours of mice and has used data obtained from both the labelled and unlabelled cell populations to derive the ratio of proliferative cells to total cells (the growth fraction)5,6. In the method presented here, applicable whenever a cohort of cells (that is, a fraction of the population) is labelled, the data for the labelled and unlabelled cells are analysed separately. In this way more information is obtained than when either only the labelled cells are studied or when data for the two cell populations are combined. The generation time of both labelled and unlabelled cells can be determined and compared, thus providing a method by which one aspect of toxicity of tritiated thymidine can be examined.

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    Leblond, C. P., and Messier, B., Anat. Rec., 132, 247 (1958).

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    Patt, H. M., and Maloney, M. A., in Kinetics of Cellular Proliferation, edit. by Stohlman, jun., F., 201 (Grune and Stratton, New York, 1959).

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    Baserga, R., Kisieleski, W. E., and Halvorsen, K., Cancer Res., 20, 910 (1960).

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    Lesher, S., Fry, R. J. M., and Kohn, H. I., Exp. Cell Res. (in the press).

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  1. Division of Biological and Medical Research, Argonne National Laboratory, Argonne, Illinois

    • R. J. M. FRY
    • , S. LESHER
    •  & H. I. KOHN
  2. Radiological Laboratory, University of California Medical School, San Francisco

    • R. J. M. FRY
    • , S. LESHER
    •  & H. I. KOHN


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