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Biomedical subjects

F Halberg

Publications and source records attributed to F Halberg.

568 records · Page 32Linked to original sources
PubMedDate not supplied

Chronome assessment of circulating melatonin in humans.

BACKGROUND: Melatonin (MEL) production occurs mainly during the dark span. A prominent circadian variation is demonstrated in both blood and urine in humans. MATERIALS AND METHODS: The circadian, circannual, age and gender patterns of MEL were concomitantly investigated in 40 men and 132 women, each providing blood samples every 4 hours for 24 hours for conventional and cosinor analysis. RESULTS: Circulating MEL is circadian periodic (P < 0.001), peaking at night. The MESOR (rhythm-adjusted mean) is higher in women than in men. The circadian amplitude decreases with age. Both are modulated by a circannual variation, the MESOR peaking in winter (P < 0.001) and the circadian amplitude in summer (P < 0.05). CONCLUSIONS: Samples, unqualified as to gender, age and/or season, incompletely characterize the circadian MEL patterns. This chronome approach detects changes that may escape detection otherwise, checking whether a value is too high or too low, and also whether "swinging" occurs to the right extent.

Adult↗
PubMedDate not supplied

The human blood pressure chronome: a biological gauge of aging.

OBJECTIVE: This study examines changes in the broad time structure (chronome) of blood pressure (BP) as a function of age. DESIGN: This is an observational study. SETTING: The study was conducted at the Chronobiology Laboratories of the University oi Minnesota, Minneapolis, Minnesota. PARTICIPANTS: Seventy-two individuals 12 to 106 years of age provided a 7-day record of BP measured indirectly with an ambulatory monitor, mostly at 15-60-minute intervals. MAIN OUTCOME MEASURES: Amplitudes in least squares spectra at frequencies of 1 to 7 cycles per week and 1 to 8 cycles per day were analyzed by linear regression as a function of age. A two-way analysis of variance for subjects classified in four age groups tested for any variance transposition from the circadian (about-daily) to the infradian (frequency lower than one cycle per day) and/or to the ultradian (frequency higher than one cycle per day) domain. RESULTS: The decreasing circadian BP amplitude with age is accompanied by an increase in infradian and ultradian prominence. The day-to-day variability in circadian characteristics also increases with age. CONCLUSION: A variance transposition from the circadian to the neighboring ultradian and infradian domains characterizes the elderly human BP chronome, as a new, technically implementable biological, rather than chronological, gauge of human aging.

Adolescent↗
PubMedDate not supplied

Studies on circadian periodicity of urinary corticoids in carcinoma of the breast.

The circadian periodicity of urinary 17-ketogenic steroids (17-KGS), 17-ketosteroids (17-KS) and creatinine (Cr) was studied preoperatively and on the 9th postoperative day in 25 histopathologically proved breast cancer patients and in 15 healthy Indian women under tropical conditions. A statistically significant rhythm was observed in healthy participants for all three variables. Urinary corticoids were markedly elevated in breast cancer patients irrespective of the stage of the disease in comparison with healthy controls. The degree of elevation was more pronounced preoperatively in advanced stage breast cancer in comparison with other groups. After mastectomy, the values of all three variables declined markedly, approaching usual values with a circadian rhythm resembling the pattern found in clinical health.

17-Ketosteroids↗
PubMedDate not supplied

[Chronobiological profile of arterial blood pressure and heart rate in a family group determined by automatic monitoring].

Over a week, blood pressure (systolic, mean and diastolic) and heart rate were determined in a family, by means of automatic, uninterrupted monitoring. The chronobiological profile for each family member was prepared in time series of various periodicities. An ample circadian component and a lesser circaseptan component were apparent. Clear phase differences were identified among the four cardiovascular variables studied. The chronobiological profile of the children was closer to that of the father than to that of the mother.

Adolescent↗
PubMedDate not supplied

Chronomes render predictable the otherwise-neglected human "physiological range": position paper of the BIOCOS project. BIOsphere and the COSmos.

On June 30, 1997, the Russian Academy of Medical Sciences convened a special session at its headquarters to discuss and, at the end of this meeting, to unanimously endorse a project on "The BIOsphere and the COSmos" (BIOCOS), a follow-up on various international resolutions reviewed elsewhere [1]. BIOCOS recommends the introduction of the science of the body's time structure, chronobiology [2], into basic science and health and environmental care via national physiological and physical monitoring and educational endeavors. More specifically, BIOCOS aims at the collection and archivization for basic and applied purposes at different latitudes and longitudes of physical and physiological time structures, or chronomes [1, 3]. The first step of BIOCOS is the systematic mapping of variation in human blood pressure and heart rate from womb to tomb and the opportunistic mapping of other variables in human and other life forms. On July 1, 1997, BIOCOS was introduced at the XXXIII International Congress of the International Union for Physiological Sciences in St. Petersburg, in the context of a symposium on "Adaptation to the Environment". Thereafter, BIOCOS was presented in a course on chronobiology in Mexico City, August 27-30, 1997, in lectures at Masaryk University, Brno, Czech Republic (September 1, 1997); at a meeting on "Chronobiology with roots in the cosmos", September 2-6, 1997, in Stara Lesna, Slovakia, under the auspices of the Slovak Medical Society; at Safarik University in Kosice (September 8) and the Institute of Clinical Endocrinology in Lubochna (September 9), both in Slovakia and at the International Conference on the Pineal Gland and Cancer (October 2-5, 1997) in Blaubeuren, Germany.

Aerospace Medicine↗
PubMedDate not supplied

[The origin of the biological week from data on the rhythm of cardiac contractions in people during the solar activity cycle].

A human biologic week in the heart rate variations was compared with the variations of the sunspot area and geomagnetic activity over the solar cycle. The low ratio of amplitude of circaseptan rhythm to that of circadian rhythm in the heart rate of several clinically healthy men who did around-the-clock self-measurements in a number of years coincides with the period of anomalously low amplitude of circaseptan rhythm of the solar activity. Results herein suggest that physiologic circaseptan rhythms are built into the genome being adapted evolutionary to the original heliogeomagnetic environmental circaseptans.

Adaptation, Physiological↗
PubMedDate not supplied

[Quasi-eleven year modulation of global and spectral features of geomagnetic disturbances].

Variations in spectral characteristics of the Kp-index of geomagnetic activity during the solar activity cycle were studied in order to assess the role of its rhythms in the formation of temporal structure of biological objects. It is shown that most spectral components of the Kp-index are modulated by the 10.5-year periodic rhythms in solar activity variations, while its circasemiseptan component (3.5 days) exhibits an 11-year rhythm. Since it is a circasemiseptan rhythm that is characteristics of biological objects (e.g., unicellular algae), it can be assumed that geophysical rhythms played a substantial role in the formation of biological rhythms during evolution.

Humans↗
PubMedDate not supplied

[Effect of geomagnetic activity on the human body in extreme conditions and correlation with data from laboratory observations].

It was hypothesized based on previous laboratory observations and theoretical concepts that astronauts working at the "Mir" station under zero gravity conditions exhibit enhanced sensitivity to geomagnetic disturbances. The result of studies made it possible to reveal the dynamics of changes in cardiovascular characteristics separately in the main phase and the phase of storm restoration. A similar dynamics of cardiac activity was observed in experimental rabbits during geomagnetic storms.

Animals↗