Chronobiologia最新文献

The core temperature temporal behavior of DBA/2 mice (11 normal and 13 with an ascites tumor) was studied using surgically implanted radio telemetry transmitters. Normal mice continuously displayed a stable 24 hour temperature rhythm. Tumor-bearers displayed a progressive deterioration of the temperature rhythm following inoculation with tumor cells. While such disruptions have been noted by others, details on the dynamics of the changes have been mostly qualitative, often due to time-averaging or steady-state analysis of the data. The present study attempts to quantify the dynamics of the disruption of temperature rhythm (when present) by continuously monitoring temperatures over periods up to a month. Analysis indicated that temperature regulation in tumor-bearers was adversely affected during the active period only. Furthermore, it appears that the malignancy may be influencing temperature regulation via pathways not directly attributable to the energy needs of the growing tumor.

Self-reported activation measures through adjective checklist have not been widely tested in the field of chronopsychology. Previous studies have mostly explored two daily measurements (morning/evening) and reported differences as a function of the time of day. The aim of this study is to determine whether the energetic arousal, tensional arousal and hedonic tone scales of the Matthews' inventory (UMACL) change the function according to the time of day (09(00), 13(00), 17(00) and 21(00)). We also test whether morningness, sex or personality factors influence the results. The sample consisted of 156 university students of age 17-28 years, 41 of whom were men and 115 women. When all the subjects are considered, all UMACL scales show significant differences according to the time of day. Subjects presented a fall in their energetic arousal and hedonic tone from morning to evening, while tensional arousal increased throughout the day. However, when individual differences are taken into account, only morningness influences energetic arousal and hedonic tone. Morning-type subjects show an earlier peak time than evening-type subjects in both scales. The use of adjective checklist measures has been shown to be a valid method of revealing Self-reported circadian variations, and to assess individual differences in terms of their circadian typology or morningness.

The realization of the implications of splitting the atom ended a tragic war. The nuclear age ensued. Likewise, a devastating escalation of health care costs could be ended by realizing the implications of splitting the normal range. Our currently disease-cure-oriented health care system does too little too late. Chronobiology could change this status quo into a system that recognizes risk early; it would gain new information from the resolution of predictable variations that take place within the physiologic range. Investment into vaccinations leads to returns in the form of savings in suffering and cost. A relatively modest investment into a 'Blood Pressure Health Start', pursued while chronobiology is being taught as an integral part in primary, secondary, higher and continued education, may not only drastically and in some respects promptly reduce the health care bill, but it would help the economy of the country that invests into the development of instrumentation for a chronobiologic systems approach. On the one hand, reducing the number of cases of catastrophic diseases, via improved diagnosis (to start with) of the blood pressure status, is likely to substantially reduce the budget deficit by reducing the legitimate and essential costs of care (to start with, of strokes and heart attacks, that kill more people than all other diseases combined and that have blood pressure disorders as their major risk factor). On the other hand, by implementing a novel health care system which also involves new technology that can become in demand worldwide, any trade balance will be improved.(ABSTRACT TRUNCATED AT 250 WORDS)

Clinical trials would gain from incorporating 'Phase 0' chronobiologic pilot designs both from the viewpoint of (statistical) power and cost-effectiveness. Herein, this statement is documented by power computations and is further illustrated by clinical examples answering specific questions. Power computations show the merits both of chronobiologic designs (that assign samples at equidistant intervals to cover one full cycle of anticipated pertinent rhythms) and of chronobiologic analyses (the cosinor versus the analysis of variance). Randomized clinical trials would gain from incorporating a concern for timing as well as dosing in all three stages of clinical trials (Phase I, II and III focusing on toxicity, efficacy and a comparison with the current best treatment, respectively) and could be cost-effectively preceded by 'Phase 0' trials so as to detect, sooner and with smaller sample sizes, desired or undesired effects that may otherwise be missed.

The ESR is used as a common human clinical laboratory test which allows identification in the presence and intensity of active pathologies. In this paper, the seasonality of the variable was described and modelled. Monthly means and medians of a transformation of this variable were used. Nonparametric smoothing techniques and cumulative periodograms permitted to describe the seasonal behavior, and parametric models allowed to demonstrate its significance.

A chronobiologic approach is much more than fine-tuning that may perhaps be considered after a drug has been identified as useful; at very little cost at first, a Phase 0 chronobiologic trial may show that there is danger that a given drug may do more harm than good when administered at the wrong time. At least equally important, the chronobiologic approach may recognize the usefulness of a drug that is active only at the proper time. When different chronobiologic timing results in opposite effects from the same total weekly dose of the same drug, it is clear that timing cannot be separated from dosing. The time structure-adjusted pattern of drug administration can make the difference between the undesired stimulation of a malignant growth and shortening of survival time and the desired growth inhibition and prolongation of survival. The experience with lentinan, namely that this immunomodulating drug can stimulate as well as inhibit the development of a cancer, may apply to many more therapeutic agents in a day and age of biologic response modifiers. It is a point of particular importance that an immunostimulator ought not be given at a time when it can be an immunosuppressor. What is surprising to many under these circumstances is that chronobiologic designs are also cost-effective. Most scholars believe that if a test is carried out at six times, it will cost six times more, will require six times more patients and six times more work. We believe we have shown that the reverse holds true: if so, the discussion of the pros and cons of chronobiometry and of neglect thereof becomes one of ethics. Figures 1-5 depict the status quo. Examples have been given to show that some effects can be obtained only at certain times with the dose used. Figure 8 reveals the doubling of the desired anticancer effect by timing treatment according to an unspecific marker rhythm. The recognition of the power of chronobiologic designs coupled to the discovery of large-amplitude rhythms in non-invasively determined marker chronomes is a challenge that can be exploited, particularly in the treatment of cancer. Marker determinations are still expensive, but once the cost of their development is paid, a market is established, and the community is trained in self-help, the responsibility now assumed by most diabetic patients for themselves can also be shouldered by cancer patients.(ABSTRACT TRUNCATED AT 400 WORDS)