Incidence Of Myeloid Leukemia Research Articles

Effect of interferon on the course of spontaneous and radiation-induced renal lesions in the RF-Un mouse.

Summary. A spontaneous form of progressive intercapillary glomerulosclerosis (IGS) develops in RF/Un mice in early life and is accelerated by neonatal irradiation. The lesions are similar to those seen in mice with viral infections and may be of viral origin. In the present study, daily injection of the antiviral agent interferon appeared to retard the course of both spontaneous and radiation‐induced IGS in RF/Un mice. In addition, the occurrence of the lesions was independent of the occurrence of myeloid leukemia, suggesting that if IGS is viral mediated, the virus is different from the agent responsible for the high incidence of myeloid leukemia in mice of the RF/Un strain.

Influence of microbial environment on development of myeloid leukemia in x-irradiated RFM mice.

AbstractThe incidence of radiation‐induced myeloid leukemia, to which conventionally reared RF mice are unusually susceptible, has been observed to vary among colonies of RFM mice maintained in different microbial environments. The incidence in germ‐free RFM males exposed to 300 R of X‐irradiation at 5 to 6 weeks of age was only 1%, whereas that in their conventionally reared counterparts was 13%. In similarly irradiated RFM males subjected to microbial shock by transfer from an environment containing a limited number of bacteria to a conventional microbial environment, the incidence was 20%. The results suggest that the incidence of myeloid leukemia varies inversely in relation to the bacterial “cleanliness” of the environment, possibly as a result of associated variations in granulocytopoiesis.

MYELOID LEUKEMIA IN THE MOUSE.

The incidence of myeloid leukemia is elevated in RF mice acutely exposed early in adult life to 50 to 400 rads of whole-body x radiation. The relation between incidence and dose is complex, the yield of leukemias declining as the dose is increased above an optimal level. X rays and gamma rays are less leukemogenic when administered daily at low dose rates than when administered in one or two large exposures at high dose rates. The leukemogenic effectiveness of fast neutrons depends on the neutron energy but appears generally comparable to that of x rays. In contrast, however, the effectiveness of fast neutrons shows no detectable reduction with decrease in dose rate. A given dose in air to part of the body is less leukemogenic than the same dose in air to the whole body, but quantitative data on the relative importance of the integral dose and of the volume and region of the body irradiated are not available. The average induction period of leukemia after wholebody x irradiation is 6 to 12 months depending on the dose, although the earliest radiogenic leukemias become detectable within two months. In contrast to the relatively long average latency of leukemia induced bymore » irradiation, the neoplasm appears in a significant number of nonirradiated recipients within one month after injection of cellfree filtrates of leukemic tissue. The age-specific death rate from the disease is biphasic. Radiation markedly advances the onset of the early peak, which occurs in controls between the fifteenth and eighteenth months of life. Radiation affects the late peak (occurring at 22 to 24 months) relatively less, if at all. The results of these studies suggest that the leukemic transformation induced by radiation evolves through multiple changes rather than through a single, one-hit type of alteration in a host cell or in the virus-host relation. (auth)« less

Leukemogenic Effect of Myleran on the Mouse Thymus

SummaryMyleran given before or after whole-body X-irradiation increased the incidence of thymic lymphomas and decreased the incidence of myeloid leukemias in male mice of the RF strain. The magnitude of these effects varied, depending on the time Myleran was administered in relation to irradiation. Effects were greatest when Myleran was given 15 days before exposure to X rays.These results are paradoxical in view of the myelotoxic action of Myleran and attest further to the complexity of factors influencing susceptibility to radiogenic leukemia.

The Effects of Cortisone on the Development of Spontaneous Leukemia in Mice and on Its Induction by Irradiation

Abstract The development of spontaneous lymphoma in a high leukemia strain of mice was inhibited by administration of cortisone, although the hormone-induced atrophy of the thymus and other lymphoid tissues was only transient. Inhibition of lymphoma formation resulted from only three successive daily injections of cortisone but was greater if the cortisone administration was prolonged for three months. A high incidence of myeloid leukemia was induced in a low-leukemia strain of mice by a single exposure to 350 r of x-radiation. Cortisone was without effect on the induction of myeloid leukemia. Cortisone administered preirradiation increased, and postirradiation decreased, the incidence of radiation-induced lymphomas in male mice.

A STATISTICAL STUDY OF MORTALITY FROM LEUKEMIA

Abstract The recorded death rate from leukemia in the United States has risen continuously since 1900, with an accelerated rate of increase since 1930. The rise from a rate of 1.9 per 100,000 population in 1920 to 3.7 in 1940 represents an increase of 94.7 per cent in this twenty-year period. This increase cannot be accounted for by changes in the age distribution of the population, for the age specific death rates have increased in each age group. The factor of increasing recognition of the disease resulting from improved diagnostic technics and greater use of hospitals with their laboratory facilities must be given adequate consideration in an effort to determine the causes for the rising death rate. White persons are affected at a rate more than twice as great as nonwhites. Some of the difference must be attributed to variations in the availability of diagnostic services. Males experience a rate approximately one-third greater than females. Leukemia affects persons in the older ages, particularly over 55 years, with the greatest frequency, and the population under 5 years of age experiences a mortality rate higher than any other age under 45 years. In the intermediate ages the death rate falls to the lowest point. In 1940 the death rate from leukemia for all ages was 3.7 per 100,000 population. The highest rate, 15.7 per 100,000 occurred in the age group 75-84 years. Under 1 year the rate was 4.9 per 100,000. The lowest rate, 1.5 per 100,000, occurred in the ages from 15 to 2.4 years. Figures for the city of Baltimore for the five-year period 1939-1943 indicate an almost equal incidence of lymphoid and myeloid leukemia. Nearly two-thirds of the deaths studied in Baltimore were reported as acute leukemia. Acute myeloid leukemia appears to be more common than acute lymphoid. After age 45 chronic leukemia is more frequently observed; younger persons experience acute leukemia most commonly. Undoubtedly many deaths result from leukemia in which this disease was neither diagnosed nor recorded on a death certificate. Clinical evidence indicates that the causes in which this failure would occur most commonly are cancer, anemia, and diseases of the spleen. Statistical evidence reveals that these conditions are certified jointly with leukemia in a significant number and proportion of cases. Comparison of the experience of several countries indicates that the general trends of mortality from leukemia in the United States are common to the other communities. The death rates per 100,000 population in 1931 adjusted for differences in age and sex composition of the population were: United States, 3.5; England and Wales, 3.0; Paris 2.5; and Canada 2.3. Each year since 1940 more than 5,000 persons in the United States have died from leukemia.