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Biomedical subjects

E Halberg

Publications and source records attributed to E Halberg.

At least 19 recordsLinked to original sources
PubMed2002

The biological effects of solar activity.

The synchronization of biological circadian and circannual rhythms is broadly viewed as a result of photic solar effects. Evidence for non-photic solar effects on biota is also slowly being recognized. The ultrastructure of cardiomyocytes from rabbits, the time structure of blood pressure and heart rate of neonates, and the heart rate variability of human adults on earth and in space were examined during magnetically disturbed and quiet days, as were morbidity statistics. Alterations in both the about-daily (circadian) and about-weekly (circaseptan) components are observed during disturbed vs. quite days. The about-weekly period of neonatal blood pressure correlates with that of the local geomagnetic disturbance index K. Circaseptans which are seen early in human life and in various other forms of life, including unicells, may provide information about the possible site(s) of life's origins from an integrative as well as adaptive evolutionary perspective.

Animals↗
PubMed1987

Altered circadian plasma cortisol and aldosterone group rhythms in Cushing's syndrome versus obesity and health.

According to textbooks, Cushing's syndrome (CS) is associated with a loss of the circadian rhythmicity in circulating cortisol. Documented cases of a persisting rhythm in CS are regarded as an exception. Herein, we show that a circadian rhythmicity in plasma cortisol, albeit of much reduced amplitude and with altered timing, remains a group characteristic of patients with CS, characterized further by a circadian rhythm in circulating aldosterone. In Lubochna, Czechoslovakia, 28 patients with CS, 120 patients with obesity imitating CS, 70 subjects with simple obesity, and 19 nonobese controls were sampled at 0800, 1600, 2000, 0000, and again at 0800 on the following day. In Rome, five women and three men with CS and 27 women and 30 men in clinical health gave blood for aldosterone determinations at 0600, 0800, 1200, 1800, 2000, and 0000. Results were first analyzed by single cosinor and then summarized by population-mean cosinor. A group rhythm was demonstrated for all categories of subjects by the methods employed, although, compared to health and even to simple obesity or Cushing-imitating obesity, the amplitude of the rhythm in CS was much reduced. Subgrouping according to etiology and individualized assessment in practice are mandatory. The scope of this group rhythm assessment, however, is merely to document that as a general rule the circadian rhythms in circulating cortisol and aldosterone persist in CS documented by surgery or at autopsy.

Aldosterone↗
PubMed1987

Circadian urinary characteristics of adolescents: sensitive dynamic indices complement mean values as new physiologic endpoints.

To introduce the study of physiologic urinary rhythms into secondary education, six girls and 11 boys, 14-18 years of age, collected urine at about 3-hr intervals for 24 hr. The volume and the excretion in urine of creatinine, potassium, and sodium were determined. Blood pressure was measured during the same 24-hr span to teach the students some elements of chronobiologic sampling and analysis in the context of evaluating the risk of developing a high blood pressure later in life. Herein, we examine on urinary excretory rates whether dynamic chronobiologic endpoints such as the amplitude (A) and/or acrophase (phi) may complement the more static mesor (M) in distinguishing groups of adolescents. In a comparison of the two sexes, dynamic characteristics of the urinary excretion of sodium and of the ratio of sodium/potassium do not separate the two groups, while the M does so. The reverse holds true for the excretion of potassium. In the case of urinary creatinine, the circadian A in itself is an index suggesting a "sex" difference; whereas in urinary volume, the M alone, and to a lesser extent the combination of (M, A, phi), yields a P value below the 5% level. The groups are rather small and heterogeneous; a study of ethnicity is beyond our scope. These qualifications notwithstanding, results indicate the need for testing multiple chronobiologic characteristics in comparing groups whether one's interest in the future relates to ethnicity, sex, or other factors. Such studies of urinary rhythms of high-school students serve for instruction and research and to instill responsibility for self-help in preventive health care.

Adolescent↗
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↗
PubMed1987

Ultradian rhythmometry by adaptive line enhancer.

Widrow's adaptive line enhancer (ALE) was applied to human rectal temperatures at 12-min intervals for 9 days. Changes along the scale of 9 days in circadian pattern suggested the occurrence of infradian variation, resolved by analyses of the entire series by linear-nonlinear rhythmometry. Once the original signal is filtered to extract the circadian component, ultradian components appear. A wide peak with a period of about 100 min, seen each day, may reflect a consistent ultradian component. Other peaks at lower ultradian frequencies (around a period of approximately 8 hr) are unsteady and may correspond to harmonics of the partially extracted circadian oscillation. Ultradian components with periods of approximately 131 and approximately 68 min were also suggested independently by population-mean cosinor summarizing data collected over a total of 158 days. Results show the ability of ALE to detect and reconstruct periodic components in noise and to track their changes in frequency, notably when other methods are also used to assess separately the components and the corresponding uncertainties involved.

Biometry↗
PubMed1986

Evidence for a circaseptan and a circasemiseptan growth response to light/dark cycle shifts in nucleated and enucleated Acetabularia cells, respectively.

Nucleated as well as enucleated Acetabularia mediterranea cells were subjected to 14 different patterns of shifts in a regimen of 12 hr of light alternating with 12 hr of darkness in four 30-day long experiments. With one exception, which might be due to a circannual modulation, these experiments showed that nucleated cells had maximal growth rates when a shift was performed every 7th or 15th day. In enucleated cells, maxima were observed on shift schedules that were about 3-4 days rather than about 7 days apart. The results indicate that in the unicellular green alga Acetabularia a rhythm of about 7 days (circaseptan) exists and that removal of the nucleus results in a circaseptan frequency multiplication.

Acetabularia↗
PubMed1986

Circadian characteristics of urinary melatonin from clinically healthy young women at different civilization disease risks.

Rhythm characteristics in the about-daily (circadian) and about-yearly (circannual) frequency ranges were assessed for urinary melatonin. Clinically healthy women in Minnesota, USA, and Kyushu, Japan, were sampled around the clock once in 1-4 seasons. Possible differences that could reflect the large difference in breast cancer incidence in these two geographic locations were investigated. Each subject's risk of developing breast cancer, cardiovascular diseases resulting from an elevated blood pressure, and emotional conditions was numerically evaluated according to epidemiologic questionnaires. A prominent circadian rhythm characterizes urinary melatonin in both populations, peaking in the middle of the night. The American women exhibit a larger circadian rhythm-adjusted mean (mesor) than do the Japanese women. A circannual rhythm is also apparent in the North American women, but not in the Japanese women. The circadian mesor of urinary melatonin correlates negatively with the risk score of emotional depression and positively with that of developing cardiovascular diseases.

Adolescent↗
PubMed1986

Circadian characteristics of urinary epinephrine and norepinephrine from healthy young women in Japan and U.S.A.

Clinically healthy diurnally active young adult women were studied during the same season (March) at the Universities of Kyushu (Fukuoka City, Japan) and of Minnesota (Minneapolis, U.S.A.), under comparable conditions, except that the habitual diets were not changed. The subjects (20 Japanese and 16 Americans of mixed Caucasian background) were studied over a single 24-hr span. Urine was collected at 4-hr intervals. A circadian rhythm in total urinary norepinephrine excretion showed similar characteristics in Japanese and Americans. In epinephrine excretion, the Japanese women showed a statistically significantly higher amplitude with higher peak values, but no statistically significant difference in the rhythm-adjusted mean. This intergroup difference is strictly time dependent; it does not come to the fore in urine samples covering the nocturnal rest span of the subjects.

Adult↗
PubMed1983

Pineal modulation of ACTH 1-17 effect upon murine corticosterone production.

In tests of corticosterone production in vitro, aqueous pineal homogenate (APH) modulates the effect of a short-chain ACTH analogue, ACTH 1-17, added to adrenals from different circadian stages. Adrenal and pineal glands from female B6D2F1 mice, standardized on staggered LD 12:12 regimens, were obtained at the same clock-hour from each room, in order to cover 6 different circadian stages. Adrenals from each circadian stage were bisected and incubated with APH from the same circadian stage (isophasic incubation) or from one of the other 5 circadian stages (heterophasic incubation). ACTH 1-17 (0.05 IU) was added to each incubation medium. After 4 hours of incubation at 37 degrees C with 95% O2 and 5% CO2, the media were stored at -20 degrees C until corticosterone RIA were done. APH was found to have a statistically significant modulatory effect upon the stimulation by ACTH 1-17 of adrenal corticosterone production in vitro. This APH effect changed rhythmically as a function of circadian stage from amplification over no effect to attenuation, as a so-called feed-sideward.

Adrenal Glands↗
PubMed1983

Lighting cycle and social isolation affect development of elevated blood pressure in spontaneously hypertensive rats.

Around-the-clock blood pressure measurements repeated from the 2nd to 6th month of life in spontaneously hypertensive rats (SHR) quantify circadian rhythmicity during the development of an elevated mean blood pressure. The rise in overall pressure is aggravated by social isolation in SHR maintained on a 12-hour white light/12-hour dim red light cycle, but not in SHR kept in continuous dim red light. The demonstration of this interaction is not possible with blood pressure measurements performed only at certain (convenient) times: failure to quantify the circadian rhythm in systolic blood pressure leads to conclusions which can vary with the circadian time at which measurements are made, even in comparisons at the same fixed clock-hour. Thus, in order to model and optimize multiple factors interacting in the genesis of overall mammalian pressure in SHR, rhythmometry is an indispensable tool as it is in other fields.

Animals↗
PubMed1981

Changes with age characterize circadian rhythm in telemetered core temperature of stroke-prone rats.

In a stroke-prone (SP) strain of laboratory rats, aging is associated with quantifiable changes of the circadian rhythm in body core temperature: (1) its timing becomes less tight, as revealed by a larger standard error of the acrophase (the peak in the 24-hour cosine function best approximating all data) and (2) the acrophase in old SPs occurs earlier than in young ones--quite apart from (3) a decrease in circadian amplitude reported earlier. These results gain particularly in interest in the context of the recent finding that a large (approximately 90 degrees) acrophase-advance is associated with bilateral lesions of the suprachiasmatic nuclei in inbred (non-SP) Fischer rats. These observations may be of interest to those developing models of aging functions in disorders with blood pressure elevation.

Aging↗
PubMed1981

Familial and individualized longitudinal autorhythmometry for 5 to 12 years and human age effects.

Statistically significant and biologically interesting changes (no decrease and even an increase) with age may characterize peak expiratory flow. This variable and others were investigated in the same persons by dense measurements for several years. A possible health benefit from the monitoring of personal health thus becomes apparent. The relative prominence of changes in body core temperature and 2-min estimation with circadian rhythms, as compared to those with aging is of basic interest. The population-based presumption that aging necessarily involves an increase in overall-systolic and diastolic blood pressure is here aligned with an unusually well documented exception to this view.

Adolescent↗
PubMed1980

Circadian placebo and ACTH effects on urinary cortisol in arthritics.

The effect of placebo and ACTH-1-17 (Synchrodyn, Hoechst) upon urinary free cortisol was examined at 5 different circadian stages on 10 men with Steinbrocker Stage II-III rheumatoid arthritis. A mean cosinor analysis of urinary cortisol data from the subjects prior to treatment with either ACTH or placebo revealed a statistically highly-significant rhythm. A circadian variation in a response of urinary free cortisol to a placebo was also seen. Moreover, the response of the midline-estimating statistic of rhythm (rhythm-adjusted circadian average) of urinary free cortisol to ACTH-1-17 by patients with rheumatoid arthritis is circadian rhythmic. This reactivity rhythm is out of phase with the spontaneous rhythm in urinary cortisol acrophases-in the tests limited thus far to midsummer. The further assessment of the circadian component in the context of broader interactions by rhythms with other frequencies in various conditions in health and disease is warranted by the demonstration of rhythms here presented for men with rheumatoid arthritis.

Adrenal Glands↗