CELL LOSS FROM VIABLE AND NECROTIC TUMOR REGIONS MEASURED BY I-125-UDR

  • 1 January 1983
    • journal article
    • research article
    • Vol. 16  (6) , 549-556
Abstract
Loss of cells from vital and necrotic areas of the syngeneic mammary adenocarcinoma EO-771 in male C57BL/6J mice may be measured by use of 125I-labeled 5-iodo-2''-deoxyuridine (125I-UdR). Later than 50 h after an i.p. injection of 20 .mu.Ci 125I-UdR the incorporated activity of the entire tumor was externally measured and found to decrease with time after injection. The injected amount was neither chemo- nor radiotoxic. By injecting the vital dye ''light green'', unstained necrotic and stained viable regions were separately excised and measured for loss of activity throughout the natural development of the labeled tumor. With the appearance of necrotic regions, labeled viable cells became necrotic and activity was slowly eliminated. With increasing proportions of necrosis during tumor growth, the rate of loss of activity of the whole tumor decreased. Loss of activity from viable tumor regions reflected cell death and exceeded the loss rates of the whole tumor by a factor of 2-3. Loss of activity from the whole tumor results from a superposition of different elimination rates of viable and necrotic tumor regions and is not an immediate consequence of cell death in the course of undisturbed tumor development.