Arnold M. Markoe

Radioprotective Effect of Rauscher Leukemia Virus in the SJL/J Mouse

Experiments have been performed to study the radiosensitivity of mice with Rauscher virus induced leukemia. Development of the leukemia was evaluated by measurements of the changes in spleen weight, leukocyte count and differentials, and hematocrit. Thirty-day survival of Rauscher virus injected mice was compared with that of normal mice following: no irradiation, 490, 650, 700, 750, 800, 850, 900, 950, 1000, 1050 and 1100 R of x-rays. Thirty-day survival of Rauscher infected mice given no irradiation was only 36%. This was increased to 100% by exposure to 490 R of x-rays. From 490 to 750 R the effect of irradiation on both normal and Rauscher infected mice was equivalent. However, from 800 through 1050 R the leukemic mice showed a notably greater radioresistance than did irradiated normal mice. Thirty-day survival of leukemic mice after exposure to 800 R was twice as great as that of normal mice (80% vs. 40%). At 900 R and above none of the normal mice survived for 30 days after the irradiation. In contr...

Interrelationship of erythropoietic recovery, marrow recovery, colony-forming units, and erythropoiesis-stimulating factors after sublethal x-irradiation.

Studies have been performed to compare the injury and recovery of various elements of the erythropoietic system after sublethal (200 R) exposure to x-rays. In the peripheral blood a distinct fall and an early (6-7 day) abortive rise in reticulocytes and newly formed hemoglobin could be seen, followed by a second drop and final recovery to normal levels at 2-3 weeks after exposure. A similar drop in total nucleated cells could be seen in both femoral marrow and spleen. However, splenic recovery was slow, whereas recovery to normal nucleated cell levels occurred by 5 days in the marrow. Transplantable marrow colony-forming units also showed delayed recovery reaching normal proportions at 16 days with no abortive rise. Total blood and plasma volumes showed only minimal changes, although there was a significant drop in hematocrit. Levels of erythropoiesis-stimulating factors (ESF) showed a slight increase consistent with the fall in hematocrit but no large fluctuations which could be easily correlated with th...

Cytokinetic stability of an Ehrlich ascites tumor.

An Ehrlich ascites tumor has maintained much of its cytokinetic stability through multiple passages which included a change in host.

Radioprotective effect of Rauscher leukemia virus in the SJL-J mouse. II. Development of radioresistance and the distribution of mortality.

Studies have been performed to evaluate the development of radioresistance in mice after Rauscher leukemia virus (RLV) infection. In terms of the ability of infected mice to survive the initial 30-day period after exposure to 875 R (a

Estimation of Tumor Growth Fraction in Murine Tumors by the Primer-available DNA-dependent DNA Polymerase Assay

{\rm LD}_{95/30}

Cycling characteristics of human lymphocytes in vitro.

exposure for normal mice), increased survival became manifested between 6 and 10 days after RLV inoculation. When RLV-injected mice were x-irradiated at 10, 14, 18, 22, 26 and 30 days after infection, the respective 30-day survival values were 47, 47, 20, 52, 33 and 16%. Median survival times were more than doubled in mice irradiated 10 days after RLV infection, and remained elevated. Likewise, an apparent therapeutic effect of radiation on Rauscher disease lethality became manifested on the tenth day of infection and persisted thereafter. However, since posttreatment mortality is the result of two components, radiation-induced mortality and mortality due to Rauscher disease, the 30-day postirradiation survival parameter does not adequately describe the de...