Alpha-ray Activity in the Large Human Arteries

Abstract

HISTOCHEMICAL studies of the ageing process in human aortas and coronary arteries have shown that after the age of twenty incipient deposits of calcium are present in the media of these vessels, and these steadily increase with age. The calcium deposits in the arterial wall are not only a manifestation of ageing but in some cases also precede the formation of atheromatous plaques^1–3. The effect of the ageing process on tissue calcium metabolism is different in the skeletal system. Arnold⁴ studied the weight of ash per unit volume of bone removed at autopsy from the lumbar vertebral cortex and found a steady decrease from the age of thirty. Other authors^5,6 reported that the density of bone decreases steadily and at an increasing speed after the age of twenty in both sexes. Thus senile osteoporosis is not an ageing process with a sudden onset in middle or old age, but is a condition towards which all people gradually progress, beginning after the age of about twenty, although the rate of progress varies individually and between the sexes.