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Biomedical subjects

J Halberg

Publications and source records attributed to J Halberg.

17 recordsLinked to original sources
PubMed1987

Chronobiologic monitoring and analysis for anesthesiologists: another look at a chronoanesthetic index.

A circadian rhythm in anesthetic index is quantified by the single cosinor method in data published earlier. Although the double circadian amplitude, a measure of the extent of predictable change, is only 14%, the assumption of no rhythm (zero amplitude) is rejected at the 1% level of statistical significance. It seems likely that, in the absence of noise, the amplitude of the rhythmic change in the response to the anesthetic will be larger. The broader importance of chronobiology for anesthesiologists is also indicated. Hardware and software for the monitoring of a patient's vital signs before, during, and after surgery provide refined dynamic endpoints from the analysis of data series and lead to time-specified reference values that improve even the interpretation of time-specified single values.

Anesthetics↗
PubMed1979

Schedule shifts, life quality and quantity--modeled by murine blood pressure elevation and arthropod life span.

During the span from 50 to 100 days and beyond, the male stroke-prone Okamoto rat develops systolic blood pressure measures in excess of 200 mm Hg. In the course of developing such a marked elevation in systolic blood pressure mean, this intermittently handled male Okamoto rat exhibits a statistically significant circadian rhythm with large amplitude. This amplitude may represent, at least in part, a response to intermittent handling; it is several times larger than the amplitude for spontaneously mesor-hypertensive (but not stroke-prone) female animals of the same age.

Aging↗
PubMedDate not supplied

Chronobiology: a frontier in biology and medicine.

On the occasion of Franz Halberg's 70th birthday, some of his many achievements are reviewed. We provide a historical background to the development of chronobiology; offer insight into the current state of this new science; and sketch the promise of this discipline for health care and cure. As a tribute to Franz Halberg, in an era of fast-growing technology, an attempt is made to describe his perspective of tomorrow's medicine and biology. The many students he trained throughout his productive career face the challenge of deserving the trust he placed in them and of further implementing his vision. A leader in social pediatrics put it aptly: it will take several generations of researchers to study and master his life's work.

Animals↗
PubMedDate not supplied

Further steps toward a neonatal chronocardiology.

The study of 53 series of blood pressures at half-hour intervals from clinically healthy full-term newborns during the first days of life reveals various classifiers correlating with a history of high blood pressure: the circadian amplitude of diastolic blood pressure, the 50% range of systolic blood pressure and the standard deviation of heart rate.

Cardiovascular Diseases↗
PubMedDate not supplied

Catfish anyone?

Explore the source record for details and available documents.

Animals↗
PubMedDate not supplied

Comparative effects of meal timing on circadian rhythms of plasma insulin and skin surface temperature in non-human primates.

Circadian rhythms of plasma immunoreactive insulin and skin surface temperature were demonstrated in a group of African green vervets. Alteration in the timing of a single daily meal of fixed calorie content resulted in an acrophase shift of plasma immunoreactive insulin for the group of animals and in an acrophase shift of skin surface temperature in 7 or the 8 animals studied. The acrophase shift of skin surface temperature was considerably less then the shift of acrophase of plasma immunoreactive insulin, which closely approximated the shift in meal timing. The results of this study are compared with results of similar studies in human beings.

Animals↗
PubMedDate not supplied

Variability of human blood pressure with reference mostly to the non-chronobiologic literature.

The voluminous literature on the variability encountered in 24-h recordings of human blood pressure in health is here presented by reference to selected clinical articles. Most references are cited by number for the sake of brevity, with a few cited by author when this appears to be of particular interest. Reports of work on laboratory animals are included when the findings are directly pertinent as background to studies on human beings. Results from semiautomatic and automatic direct and indirect measurements are briefly reviewed and aligned with results from work in which blood pressure was self-measured or measured conventionally by staff. The considerable and not generally recognized range of human blood pressure variability is thus extracted from the literature. An apparently limited extent of variation is shown to result mostly from the averaging of data from individuals constituting the groups investigated. Once variation is overwhelmingly documented and recognized as a fact, the different ways in which variations are presented and utilized by different author-investigators gain in importance. In a number of studies, methods of time series analysis are used. Thus, major attention can be paid to the extent to which predictable changes, so-called rhythms, characterize the data. Circadian rhythms are found to be quite prominent. By the assessment of these rhythms and about-yearly (circannual) ones, one quantifies health and individualized risk as well as disease. Otherwise 'unmanageable' variability, reviewed herein, can be resolved by relatively simple inferential statistical procedures as a set of new endpoints. A formidable foe thus becomes a powerful friend: the rhythm characteristics can be used in cardiovascular physiology and epidemiology, and preventive and curative medicine. Long-term blood pressure monitoring is no longer a mere research tool and a curiosity for the practitioner of medicine. Results from such monitoring should immediately be used in the clinic, in the school and at home. Automatic blood pressure monitoring, cost-effectively used in combination with self-measurement, as needed, may become a routine procedure if data collection can be wedded to appropriate analyses yielding new endpoints as sensitive gauges of health.

Adolescent↗
PubMedDate not supplied

Chronobiology of human blood pressure in the light of static (room-restricted) automatic monitoring.

Systematic 24-h automatic physiologic monitoring has obvious merits, even without rhythmometry. It can lead more readily to the recognition of odd-hour blood pressure elevation (e.g., of 'evening' or 'morning' hypertension). Such a condition can constitute an initial diagnosis or it may be found under treatment that may seem to be satisfactory if its effects are assessed only on the basis of a conventional check at a casual, possibly 'wrong' time. The mere inspection of a 24-h record, however, does not necessarily allow one to make objective quantitative global statements as to a change in pattern, e.g., after a given intervention. This paper illustrates how by rhythmometry, some of the uncertainties of a subjective interpretation of a record may be removed by practitioners of medicine, as well as basic scientists interested in mechanisms of blood pressure variability. This is possible since a large part of blood pressure variability can be accounted for by its circadian periodic behavior. We herein present a methodology for data collection and analysis that allows the objective quantification of blood pressure rhythm parameters in health and disease and the derivation of reference standards for such parameters. The chronobiologic approach thus makes it possible to define 'hypertension' objectively, and to distinguish between 'mesor-' and 'amplitude-hypertension', i.e., between an elevation in overall mean and one in the predictable extent of variability. Moreover, chronobiology has shown that mesor-hypertension may be preceded by an elevation in circadian amplitude only (amplitude-hypertension). Parameter tests readily allow the assessment, in relation to an objective reference standard, of these conditions, with a defined probability. Similarly, response to drug or non-drug therapy can be established and a given intervention optimized by timing treatment. Using chronobiologic tools in cardiovascular research provides new insights into possible mechanisms underlying mesor- and amplitude-hypertension. The teaching of the chronobiology of blood pressure and autorhythmometry in schools has been proven to be feasible and has been recommended as a step toward self-help for health care.

Adolescent↗