Abstract. Circadian breast skin temperature rhythms were characterised throughout the menstrual cycle, for various locations on the left breast of ambulatory women. All subjects exhibited highly significant circadian rhythms ( P < 0.001). Changes in rhythm parameters, such as the mesor, amplitude and acrophase, were observed during the menstrual cycle. No consistent trend in these rhythm parameters was observed between subjects in relation to menstrual cycle stage. Experimental and statistical techniques used to characterise circadian rhythms in pre-menopausal women were applied to a post-menopausal woman with primary breast cancer. Comparison of rhythm parameters associated with the tumour area and corresponding site on the contralateral breast showed abnormal thermal characteristics such as elevated mesor values, decreased amplitude as well as changes in the timing of the acrophase. These properties may be exploited for the early detection of breast cancer. The project also involved the design and testing of an ambulatory device, known as the 'chronobra', for the measurement of breast skin temperature. The performance of the chronobra was in close agreement with reliable, conventional equipment. The chronobra now allows studies of breast skin temperature rhythms associated with breast disease to be extended.
A few puzzles relating to a small fraction of my endeavors in the 1950s are summarized herein, with answers to a few questions of the Editor-in-Chief, to suggest that the rules of variability in time complement the rules of genetics as a biological variability in space. I advocate to replace truisms such as a relative constancy or homeostasis, that have served bioscience very well for very long. They were never intended, however, to lower a curtain of ignorance over everyday physiology. In raising these curtains, we unveil a range of dynamics, resolvable in the data collection and as-onegoes analysis by computers built into smaller and smaller devices, for a continued self-surveillance of the normal and for an individualized detection of the abnormal. The current medical art based on spotchecks interpreted by reference to a time-unqualified normal range can become a science of time series with tests relating to the individual in inferential statistical terms. This is already doable for the case of blood pressure, but eventually should become possible for many other variables interpreted today only based on the quicksand of clinical trials on groups. These ignore individual differences and hence the individual's needs. Chronomics (mapping time structures) with the major aim of quantifying normalcy by dynamic reference values for detecting earliest risk elevation, also yields the dividend of allowing molecular biology to focus on the normal as well as on the grossly abnormal.
The authors evaluate the blood pressure variability by 7- days ambulatory blood pressure monitoring in healthy subjects and in patients with coronary heart disease.
