Alain Reinberg

Introduction to Chronobiology

Recorded recognition of the importance of biological rhythms in plants and animals dates back at least to 5000 b.c. Over the years, the understanding of rhythmic phenomena has grown, but the acceptance of chronobiology as a science has been slow nonetheless. This chapter reviews the development of modern chronobiology by recounting the milestone events that have contributed to the current knowledge in this field, and discusses why chronobiology has developed slowly as a science.

Circadian reactivity rhythms of human skin to histamine or allergen and the adrenal cycle

Abstract Six adults, apparently healthy subjects, were standardized, for one week on a routine of diurnal activity and nocturnal (2400-0800) rest. Circadian rhythms in cutaneous responses (erythema and wheal areas) to constant intradermal injections of histamine (10 μg) and of 4880, a histamine liberator (35 μg), were found. These rhythms are synchronized roughly in phase; the cutaneous reactions reach their crest at about 2300 and their trough around 0700–1100. Circadian rhythms in immediate cutaneous response to penicillin (scratch tests) were also found in two patients suffering from humoral allergy to that drug. A crest occurred at 2300 and trough around 0700 to 1500, under the conditions studied. Data on such circadian rhythms extend to man the concept of the hours of changing responsiveness documented extensively by F. Halberg. A temporal relationship, though not necessarily a causal one, has been defined between the circadian rhythms in cutaneous responsiveness and those of the integrated 4 hourly urinary excretion of 17-hydroxy-corticosteroids, 17-ketosteroids and potassium. Adrenal hormone excretion showed a trough at about 2300 to 0300 and a crest at about 1100 to 1500. Several theoretical and practical aspects of those results are discussed.

Circadian rhythm in duration of salicylate excretion referred to phase of excretory rhythms and routine.

Summary The duration of urinary salicy-late excretion following oral administration of the drug was studied on 6 human subjects standardized on a routine of sleep daily from 23:00 to 07:00. The drug was administered to each of the 6 subjects at 4 different time points, i.e., at 07:00, 11:00, 19:00 or 23:00 (4 separate tests at least 1 week apart). Average duration of drug excretion depended on the time of its administration. A circadian rhythm in this pharmacologic phenomenon was detected and analyzed by the so-called cosinor method and such results agreed with impressions gained from a conventional time plot of the data. By cosinor, duration of salicylate excretion was found to be longest when the drug was administered about 06:41. The 95% confidence arc of this circadian crest-phase estimate extends clockwise from 01:45 to 10:52. When expressed in degrees (with 360° = 24 hours), in relation to the middle of the daily span of rest and/or sleep, the crest ϕ of the rhythm in drug excretion occurs with a delay of 55° from this ϕ reference, the confidence arc of the crest extending clockwise from —341° to —118°. The pharmacologic rhythm here reported also is expressed in relation to the timing, in the same subjects, of 2 well-known excretory rhythms—in 17-OHCS and potassium excretion. The latter rhythms were determined on each subject in 2 separate 48-hour profiles and were also evaluated by the cosinor method, with excellent agreement of the ϕ and the C from one profile to the next.

Circadian reactivity rhythm of human skin to house dust, penicillin, and histamine

Abstract Circadian rhythms characterize the extent of erythematous allergic response to fixed doses of house dust extract as well as penicillin. In the evening for diurnally active man, or, more generally, during the interval from 17.5 to 19.5 hours following the midpoint of the daily sleep span, a positive test may be more readily elicited than at other test times. Crests in the susceptibility rhythm to the allergens coincide roughly with the peaks of statistically significant changes characterizing the response of healthy subjects to a fixed dose of histamine and occur near the circadian trough in plasma corticosteroid levels, gauged in this study by urinary 17-hydroxycorticosteroid (17-OHCS) determinations. The findings, evaluated by electronic computer procedures, reveal the basic periodicity in mans susceptibility to a broad range of potentially harmful agents, while accounting on the practical side for some of the variability in cutaneous test results.

Agreement in endpoints from circadian rhythmometry on healthy human beings living on different continents.

Circadiane Akrophasen — Gipfel der ungefähren 24-h-Periodik — von Blut- und Harnkortikosteroiden, Kalium im Harn, Körpertemperatur, Pulsrate und 2-min-Schätzung wurden mittels elektronischer Anpassung einer Kosinusfunktion vermöge der Methode der kleinsten Quadrate bestimmt. Solche Charakteristika circadianer Rhythmen empfehlen sich als Referenzstandarde dem Mediziner und Biologen durch ihre zufriedenstellende übereinstimmung in Daten von Untersuchungen auf verschiedenen Kontinenten mit zum Teil unterschiedlichen Methoden.

LARGE-AMPLITUDE CIRCADIAN RHYTHM IN HELPER:SUPPRESSOR RATIO OF PERIPHERAL BLOOD LYMPHOCYTES

SIR,-We report here preliminary results from studies of circadian rhythm in T lymphocyte subtypes in two apparently healthy subjects. Ritchie et all have reported significant circadian rhythms.in healthy subjects for total circulating lymphocytes and for absolute numbers of Leu 4 (all T), Leu 3a (T helper), and Leu 2b (suppressor-cytotoxic) cells, but not for the helper:suppressor ratio. They used mouse anti-Leu antibodies (Beckton-Dickinson) and counted fluorescent lymphocytes by flow cytometry. Our methodology was different. Blood (20 ml) was drawn every 4 h for 24 h from two male volunteers (aged 28 and 34), who were recumbent from 2300 hours (on April 20, 1983) to 0700 hours (on April 21 ). Leucocyte and differential counts were measured and oral temperature was recorded every 4 h as a reference function. Mononuclear cells were isolated on ’Ficoll-Hypaque’ and incubated with anti-OKT3 (labelling all T cells), anti-OKT4 (helper T cells), and anti-OKTg (suppressor-cytotoxic T cells) monoclonal antibodies, which react against lymphocyte surface antigens. The proportion of fluorescent cells per 100 cells, determined microscopically, was multiplied by the number of circulating lymphocytes per 1 venous blood. Cosinor analyses2 of the absolute number of fluorescent cells per III were done on data from both individual and two-subject time series. Significant differences in mean 24 h values of the two subjects were found. Thus, data from each subject were transformed as % of their individual 24 h mean, before group statistical analysis. Significant circadian rhythms (p<0-05) by F test, indicating rejection of the null amplitude hypothesis) were found for numbers of OKT3+ (all T), OKT4 + (T helper), and OKT8 (suppressor T cells) and the OKT 4 + :OKT 8 +

Investigative Methodology for Chronobiology

Progress in the developing science of chronobiology has closely paralleled the emergence of new and improved research methodologies. Methodological requirements for biological rhythm study have been reviewed previously (Halberg et al. 1972, 1977; Reinberg 1971, 1974; Smolensky et al. 1974). This chapter outlines a minimum set of conditions and procedures necessary for conducting sound chronobiologic investigations. The recommendations which are put forward should be regarded as proposals and/or suggestions rather than rules or criteria for judging the quality of experimentation. It is obvious that each study dictates a specific methodology depending upon, among other things, the goals of the investigation and the state of knowledge. The contents of this chapter provide necessary information for designing chronobiologic research protocols and for minimizing the occurrence of those types of mistakes typically experienced in earlier chronobiologic investigations.

Evaluation of Circadian Dyschronism during Transmeridian Flights

In order to evaluate the effects of transmeridian flights upon human beings and other organisms, several facts should be kept in mind: 1. The most powerful synchronizer for animals seems to be the alternation of light and darkness; for man, under ordinary conditions, this role is probably played by the routine of the society in which he lives. 2. There will be a lag between a synchronizer phase-shift and corresponding shifts in the circadian rhythm acrophases of the physiologic functions studied. The time required to phase-shift the latter will vary according to function and subject and may range from a few days to several weeks. 3. Adaptation time after a transmeridian flight: a) varies from subject to subject for a given physiologic function; b) varies from function to function for a given subject; c) varies for a given function with direction of flight (being shorter after an East to West flight than after a West to East flight). 4. Experiments must be rigorously controlled and the data obtained thereby objectively analyzed (using modern electronic computer methods) in order to avoid differing interpretations of results.

Carbon Dioxide, Respiratory Regulation, and Chronobiology

Today a section of biology, which may be called chronobiology, is achieving the objective description of biologic time structure—the sum total of nonrandom, and thus predictable, temporal aspects of organismic behavior, including rhythms as well as changes related to growth, development and aging.