Experimental models for the study of chronoimmunomodulation (rhythms of the springtail Folsomia candida, Collembola: Isotomidae)

A third-generation cephalosporine, cefodizime, was tested in two experiments on the springtail, Folsomia candida, used as a model of infradian rhythmicity. Any effect on ecdysis (molt), oviposition and oviproduction was sought for 6, 20 or 60 ng of cefodizime administered with brewer's yeast every other day, as compared to controls given only the yeast. Results indicate that a 20-ng dose of cefodizime on alternate days may shorten an infradian period (of molt) in the springtail.

Toward a chronoimmunomodulation by cefodizime in multiple myeloma and chronic uremia

Nine healthy subjects, 19 patients with multiple myeloma (MM) and 21 patients with chronic uremia were given cefodizime (2 g i.v.) at 2 different timepoints either in the morning or in the evening for 5 to 7 consecutive days. The following immunological parameters were comparatively evaluated before and after cefodizime administration: rosette-forming cells (RFC%), T lymphocyte subpopulations, monocyte chemotaxis index (MCI) and granulocyte chemotaxis index (GCI). Independently of the time of drug administration, a circadian rhythm was clearly detected (90% CI) as regards RFC%, CD3, CD4, CD8, CD4/CD8 before and RFC%, CD3, CD4, CD8, GCI after therapy. In addition, in patients treated at 0800 cefodizime increased the MESOR of the MCI and, to a lesser extent, of the GCI. The chronoimmunomodulatory effects of cefodizime in patients with MM and chronic uremia are discussed.

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.

Intermittent automatic chronobiologic monitoring complements daily self-measurements

The self-measurement of blood pressure for circadian rhythm assessment has been used for the evaluation, 'as one goes', of the effectiveness of treatment for high blood pressure (among other purposes). Even in a setting of high technology, with miniaturized ambulatory fully automatic recorders available, it is cost-effective to combine self- with automatic blood pressure measurement, to check on both the adequacy of treatment and the need for it. These aims were followed by an 81-year-old physician practicing autorhythmometry for over a decade.

Important time, though not causal, relations in atrial natriuretic peptide, cortisol and renin

A cosinor analysis validates a circadian rhythm in circulating atrial natriuretic peptide and quantifies its time relations to circulating cortisol and renin.

Modelling prey-predator cycles using hemipteran predators of mosquito larvae for reducing world-wide mosquito-borne disease incidence

Diplonychus indicus is an aquatic hemipterous bug known to be a voracious predator of dipteran larvae, among others, and to show a selective predation for mosquito larvae when exposed to a mixed prey diet. A datum consisted of the percentage of the fourth instar of (25) culicine mosquitoes killed by the bug. Data around the clock, published earlier (from starved adult males of this bug), reanalyzed by single cosinor, reveal a circasemidian rhythm (p = 0.004). This result prompts the recommendation of studying the time structure of prey-predator cycles further to evaluate the merits or demerits of introducing the bug in the field with the aim of reducing worldwide mosquito-borne disease incidence.

Chronomodulatory effect of cyclosporine upon survival of DBA mice with L1210 leukemia

A circadian stage-dependent anti-tumor effect of cyclosporine was tested on 268 female DBA mice, 9-10 weeks of age. The mice were kept in 6 different environmental chambers on regimens of 12h of light alternating with 12h of darkness, staggered by 4h: they were inoculated intraperitoneally with 2 X 10(5) L1210 cells at one of 6 different circadian stages. At the same circadian stage, starting 48h after inoculation, for 4 days, each mouse received the vehicle, a fixed dose of cyclosporine (15 mg/kg b.w.), a varying dose of cyclosporine 5, 10, 20 and 25 mg/kg b.w.) or no treatment. Cyclosporine prolonged survival time in a circadian stage dependent fashion (p less than 0.01), as shown by an analysis of variance and by cosinor analysis (mesor = 8.45h; amplitude = 5.45h; acrophase = 12 HALO). Cyclosporine thus acts, in a feed-sideward, as a chronomodulator of the interaction between the tumor and its host.

Cephalo-adrenal interactions in the broader context of pragmatic and theoretical rhythm models

Some of the literature on modeling of biological rhythms with mathematical, physical, chemical, biochemical, in vivo and in vitro oscillations is succintly annotated. The need for biologic models that account for the interaction of 3 or more periodic entities is indicated, documented and illustrated, with emphasis on the cephalo-adrenal network of rodents. Patterns of interaction, in this context, involve attenuation, no-effect and/or amplification by a third entity, the modulator, of the effect of an actor upon the reactor. Such feedsidewards lead to chronomodulation, a phenomenon accounting for qualitatively as well as quantitatively different modulatory effects of the same drug or other stimulus. Controversies of long standing can thus be resolved and novel effects uncovered.

Chronomodulatory infradian synchronization by placebo or ACTH 1-17 of Musca autumnalis mortality on shifted lighting regimens

The face fly, Musca autumnalis, exposed to shifts of an LD16:8 lighting schedule at varying intervals, whether previously untreated or given placebo or ACTH 1-17 treatment, before the initiation of shifts, exhibits an infradian frequency response in mortality. At overall 50% mortality, a periodicity of approximately 4.5 days is found for flies exposed to placebo or ACTH 1-17 as a response to the shift interval. As compared to controls, the mortality of flies treated with placebo or ACTH 1-17 is delayed. Not all shift schedules are detrimental; some are actually beneficial.

Circadian rhythms of adenosine deaminase activity in human erythrocytes: a transverse study on young, elderly and senile demented subjects

Adenosine deaminase activity (ADA) was determined around the clock in human plasma from different groups of subjects: presumably clinically healthy women in Minneapolis, USA; healthy medical students, healthy elderly men and women, and mentally ill patients in Paris, France. In addition to analyses of variance, circadian characteristics were estimated individually and summarized by population-mean cosinor for each group. Technical and sampling considerations are documented: the individualized assessment of a circadian rhythm in adenosine deaminase is feasible in 8 out of 11 series from clinically healthy women covering 24h at 20-min intervals. A circadian population rhythm could be determined for the elderly men and women (p less than 0.05) and tentatively (p = 0.053) for the senile demented patients. A difference in circadian group rhythm characteristics found between the healthy elderly subjects and patients with senile dementia deserves further exploration.

Testing period for single cosinor: extent of human 24-h cardiovascular 'synchronization' on ordinary routine

A clinically healthy woman monitored her systolic and diastolic blood pressure and pulse for 26 days at approximately 10-min intervals, with interruptions. Data over subspans of varying length were analyzed by single cosinor. A method for testing a period assumed to characterize data analyzed by single cosinor was introduced and programmed to compute a 95% confidence interval for the circadian period. Statistically significant deviations from precisely 24 h were found. The likelihood of their occurrence was found to vary as a function of the length of the interval analyzed. Under ordinary conditions in health, the circadian period may vary around 24 h, indicating that strict frequency-synchronization with the environment need not occur on a short-term basis. Deviations from an average circadian period may be brought about in part by infradian components modulating the circadian rhythm and by day-to-day changes in waveform.

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.

Timing of medical diagnosis and treatment: clino-circadian quantification of suppression by dexamethasone of the adrenal cortical cycle in healthy men

The inhibitory effect exerted upon the cyclic activity of the adrenal cortex by a synthetic steroid analog (dexamethasone-21-phosphate) administered at different circadian stages, has been studied previously. Reexamination of the same data by microscopic methods herein provides two sets of objective quantitative endpoints for further studies, namely 1. the characteristics of a rhythm isolated from a superimposed trend as well as noise, and 2. the endpoints of the trend itself. These endpoints quantify the effect of dose and, with the appropriate dose, the optimal timing for a given purpose may also be found.

Construction of rhythm-specified reference intervals and regions, with emphasis on 'hybrid' data, illustrated for plasma cortisol

Time-specified reference intervals, so-called chronodesms for the interpretation of single samples, have heretofore been proposed for longitudinal data, consisting of repeated samples from a single individual, and for transverse data: single time-specified samples from many individuals. Herein the problem of dealing with hybrid data, namely time series of data collected on a group of subjects, is considered for a derivation of reference intervals that take into account both inter- and intra-individual variability. The formulae are applied to cortisol data (72 samples from each of 10 healthy young adult North American women) with interpretation from both Bayesian and frequentist viewpoints. The provision of reference limits for both single samples and paired rhythm characteristics offers the opportunity of introducing an overdue time-specification and time-structure evaluation into microscopic chronobiology and through it into medical, veterinarian and other practice.

Chronobiologic serial sections of several orders

The chronobiologic serial section is described. Its applicability to the analysis of nonequidistant data is emphasized. Its ability to detect and quantify multiple components is discussed and exemplified on simulated series with various amounts of additive Gaussian noise. This least-squares method is discussed in the context of a number of complementary procedures such as complex demodulation and linear-nonlinear least-squares rhythmometry.

Toward a chronopsy: Part III. Automatic monitoring of rectal, axillary and breast surface temperature and of wrist activity; effects of age and of ambulatory surgery followed by nosocomial infection

Data of core and breast surface temperature and motor activity collected automatically with ambulatory devices, reveal circadian rhythms of different prominence in these various potential chronobiologic markers. Chronobiologic serial sections further allow the study of any alterations of the circadian rhythm parameters following ambulatory surgery. An approach using miniaturized instrumentation and methods of time series analysis may signal the danger of postoperative complications and, if it prompts timely preventive measures, may increase the safety of ambulatory surgery in particular.

Circadian murine ouabain chronotolerance revisited

Data published earlier on a possible circadian variation in murine susceptibility to intravenously-administered ouabain and analyzed by conventional biometric methods, were reanalyzed by cosinor procedures. A statistically significant circadian rhythm could thus be demonstrated, contradicting the earlier conclusion that there was no circadian rhythm in susceptibility to ouabain when injected intravenously. Results from this reanalysis agreed with those from previous investigations in which ouabain was injected intraperitoneally or subcutaneously. Thus, a circadian rhythm characterizes murine susceptibility to ouabain given via 3 different routes.

Chronobiometry with pocket calculators and computer systems

Selected methods for the study of biologic time series are reviewed and their relative merits are discussed in the light of underlying assumptions. Their potential applications are exemplified in several fields of biology and medicine. The monitoring of environmental integrity, notably of pollution, is investigated. The need for specifying optimal sampling requirements is underlined. An individualized and time-qualified definition of health by the establishment of reference intervals is required for increasingly rational individualized program for the prevention and/or treatment of disease. With these reference intervals and rhythm characteristics available, one can better interpret with single samples or time series an increased risk of a certain disease or the inception of the disease. For all of these aims the monitoring of environmental and/or personal marker rhythms is essential--to obtain large data bases from which information can be more easily derived for monitoring personal health, to recognize risk as well as to diagnose disease early and to optimize treatment by timing according to rhythms.

Toward a chronopsy: part II. A thermopsy revealing asymmetrical circadian variation in surface temperature of human female breasts and related studies

A thermorhythmometric analysis was carried out on data from a patient who underwent a prophylactic subcutaneous mastectomy, subsequently to a preoperative mammogram revealing clustered small calcifications in the left breast. The patient self-measured surface temperature of each breast, above and below the nipple, at intervals of 75 +/- 10 min for 59 h while awake. In one location of each breast, the recording thermistor-probe was insulated for 21.5 h while other probe locations remained uninsulated. The overall rhythm-adjusted average surface temperature and the extent of predictable circadian variation differed with statistical significance when the two breasts were compared. The left breast exhibited a higher rhythm-adjusted mean temperature and a lower extent of predictable circadian variation, as compared to the contralateral breast. The interbreast differences of surface temperature also demonstrated a statistically significant rhythm. A review on results of rhythmometry of breast temperature was also carried out. The thermorhythmometric findings here reported must not necessarily be regarded as indicative of cancer; they may be found in non-cancerous subjects and may or may not reflect early pathology. The objective of this publication is to suggest that non-invasive mammary thermorhythmometry may complement clinical histopathology. This subject may exemplify a new principle awaiting scrutiny with much more extensive sampling and much longer follow-up, namely that chronopathology including chronoprotopathology, alongside established diagnostic procedures, may provide an indication for prophylactic intervention.

Chronochemotherapy: L 1210 leukemia and beyond

In cancer and other therapeutic research, an interpretation of median survival times can and should take cure into account. With this qualification, an analysis of recently published data provides further statistically significant evidence in favor of cancer chronotherapy as compared to homeostatic therapy.

Toward a chronopsy: part I. A chronobiologic case report and a thermopsy complementing the biopsy

A prophylactic bilateral subcutaneous mastectomy, following a preoperative mammogram revealed clustered small calcifications in the left breast. In order to investigate the merits of thermorphythmometry, the patient self-measured surface temperature of each breast, above and below the nipple, while awake. In the case here presented, bilateral subcutaneous mastectomy followed by extensive histologic scrutiny of both breasts revealed no indication of malignancy. Bilateral fibrocystic disease with calcification and lobular hyperplasia was found. As compared to the contralateral sites, the atypical epithelial proliferation was more abundant in the mammographically and thermorhythmometrically 'abnormal' area of the left breast.