To elucidate the mechanism of granulopoiesis in the aged, we studied granulo-macrophage (GM) colony formation in 13 healthy aged persons and 8 young adult volunteers.
The results obtained were as follows:
1. GM colony formation was observed when 2×10⁵ marrow cells were treated by the addition of 10% human placental conditioned medium after 7 days culture. The aged group formed 113±19 colonies. Compared with 118±19 colonies formed in volunteer group, no significant difference could be found.
2. The concentration of colony stimulating factor (CSF) revealed no difinite influence to GM colony forming cells in both aged and volunteer group. However, to a same concentration of CSF, the aged group showed slightly depressed responsiveness.
3. Components of GM colony forming cells were differentiated by combined non-specific esterase staining.
In aged group, GM colony forming cells consisted of 91±3% naphthol AS-D chloroacetate esterase positive colonies (granulocyte colonies), 9±3% alpha-naphthyl acetate esterase positive colonies (monomacrophage colonies) and 4±3% both positive colonies (granulocyte-macrophage colonies), In volunteer group, there were 87±6%, 9±3% and 9±3% respectively. Again, no significant difference could be found.
From above findings, we assume that marrow function in the aged, compared with that of the young adults, was maintained normally with respect to colony formation and components of GM colony forming cells. On the contrary, it showed depressed responsiveness to CSF in the aged.

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The aim of this study is to compare the myocardial contractility of the healthy elderly men to that of healthy young men, all of them underwent submaximal treadmill stress tests which were negative. The study population consists of 29 healthy young (young group) and 18 old men (old group). Their average ages were 28.5±4.3 (mean±SD) in the former and 68.5±5.1 in the latter. All of them performed the graded exercise of bicycle ergometer in the supine position. Echocardiograms of the left ventricular internal dimensions with simultaneous measurements of external pulse recording were successfully obtained from all of them at rest and during the steady state of the exercise level of 75 Watts.
Changes in heart rate and peripheral vascular resistence during exercise compared to resting state showed no significant difference in both groups. Systolic and diastolic blood pressure, however, increased more markedly in the old than the young group during exercise (P<0.01), while the values at rest were not different in both groups. As to the ejection phase indices at rest, the values of stroke dimension (SD) and of mean rate of circumferential fiber shortening (VCF) in both groups were not statistically different, while those of ejection fraction (EF) and of normalized VCF were significantly smaller in the old (65.4±5.7%, 1.01±0.12sec^-1, respectively) than in the young group (70.7±5.3, 1.14±0.13, respectively) (p<0.01). It revealed, however, that EF and normalized VCF did not show any significant difference in both groups of values, when they were corrected by the left ventricular end-diastolic internal dimension. During exercise, all of these four indices increased their values significantly in both groups and the changes were more marked in the old than the young group (p<0.05-0.01). Therefore, the values in EF and normalized VCF during exercise showed no significant difference in both groups.
These results suggest that healthy elderly men have no reduction in myocardial contractility as compared to that in healthy young subjects, judged by the echocardiographic measurements. It is also suggested that these measurements can be used as the tool to differentiate the normal heart and the latent cardiac dysfunction.

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Seven hundred and fifty mg of crystaline cholesterol was administered every day as capsules for 2 weeks to 18 aged volunteers who live in Takasagoen, an old people's home in Tokyo, and the changes of plasma lipoproteins in response to cholesterol load were compared with the changes among 23 healthy volunteers aged from 20 to 42. Ages of the aged group were from 62 to 89.
Plasma VLDL, LDL, and HDL cholesterol levels did not change significantly on 2 weeks' cholesterol load in the control group. However, plasma total cholesterol decreased from 205±28mg/dl (mean±SD) to 186±26mg/dl (p<0.05) and LDL cholesterol also decreased from 149±25mg/dl to 131±24mg/dl on 2 weeks' cholesterol feeding in the aged group (p<0.05). HDL cholesterol did not change significantly in both groups. Changes of HDL₂ and HDL₃ levels were different between two groups. In the control group, HDL₂ cholesterol increased significantly from 24±10mg/dl to 35±13mg/dl on 2 weeks' cholesterol load and HDL₃ cholesterol remained unchanged. In the aged group, HDL₂ cholesterol remained unchanged and HDL₃ cholesterol decreased significantly from 22±5mg/dl to 17±6mg/dl (p<0.02) on 2 weeks' cholesterol feeding.
Changes of lipoproteins in response to cholesterol load were classified into 3 groups according to atherogenic index (LDL chol./HDL chol. ratio); increased, unchanged and decreased group. 35 percent in the control group and 17 percent in the aged group were comprised in atherogenic index increased group.
Responses to cholesterol feeding were different in the aged from the control group in this study and we considered it important clinically to examine the individual response to cholesterol feeding.

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