The effect of aging on the growth of XXXX .

@entity1 @entity694 @entity19 @entity5
Reports on the effect of @entity1 age on the prognosis for @entity694 vary. We have tested the effect of aging using a model of @entity19 @entity694 in groups of @entity19 of different ages. In experiment A, Balb/c @entity19 of age groups 3-4 weeks, 10-12 weeks, 24-32 weeks and 40-48 weeks (13 @entity19 /group) were injected with 5 X 10(4) MC-26 cells subcutaneously in the right flank. @entity5 were measured twice weekly, and the rate of occurrence of @entity5 , mortality rate, and growth rate were calculated. In experiment B, the same plan as experiment A was used, except @entity19 of age groups I (14 days), II (3-4 weeks), and III (20-22 months) were used with @entity5 doses of 1 X 10(4) cells and 5 X 10(5) cells (9-15 @entity19 /group). In both experiments, the rate of growth of @entity5 , mortality rate, and sizes of @entity5 obtained were the same. In experiment A, the rate of occurrence of the @entity5 was the same in all groups, but in experiment B the occurrence of the @entity5 varied. A palpable @entity5 appeared earliest in the weanling @entity19 (14 days), next in old @entity19 (20-22 months), and last in the young adult group (3-4 weeks). @entity5 doubling time was longest in the young adult @entity19 (7 days), intermediate in the old @entity19 (6.1 days), and shortest in the weanling @entity19 (5.5 days). Established @entity5 grew at similar rates (as assessed by doubling time), independent of host age. Mortality rates were similar.(ABSTRACT TRUNCATED AT 250 WORDS)
