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We monitored peak expiratory flow (PEF) in outpatients with adult bronchial asthma in 17 sites in Chiba prefecture 4 times daily for 2 weeks, using a peak flow meter to categorize the patients by circadian patterns of PEF. Then a sustained-release theophylline preparation formulated for once-daily dosing was administered to these patients grouped to examine the effect of the drug on circadian rhythms in PEF. Analysis was performed in 215 of total 245 patients enrolled as a result of excluding 30 ineligible patients. 187 patients (87.0%) exhibited a certain rhythm in their PEF, and 28 patients (13.0%) did not show any particular rhythm. These 187 patients with a certain rhythm in PEF were grouped into 63 patients (29.3%) of morning-dip type, 83 patients (38.6%) of peak type, 7 patients (3.3%) of evening-dip type, and 34 patients (15.8%) of flat type. And there were no trough-type patients. Uniphyl tablets were administered once a day at a daily dosage of 400 mg after supper to 124 patients of the above 187 patients grouped according to circadian patterns of PEF. Uniphyl was particularly effective in the morning-dip type and the peak type. This result suggests that it is necessary to take circadian rhythms of PEF into consideration in drug therapy for patients with bronchial asthma.
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BACKGROUND: Digitalis glycosides have been in clinical use in the treatment of congestive heart failure for more than 200 years. In recent years several trials have been conducted to address concerns about efficacy and toxicity. Although a systematic review of the literature was recently published, an update is required to include more current trials. OBJECTIVES: To examine the effectiveness of digitalis glycosides in treating congestive heart failure in patients with normal sinus rhythm. To examine the effect of digitalis in patients taking diuretics, ACE inhibitors, and beta blockers; patients with varying severity and duration of disease; patients with prior exposure to digitalis vs. no prior exposure; and patients with diastolic vs. systolic dysfunction. SEARCH STRATEGY: Electronic databases were searched between 1966 and 2000. Dissertation Abstracts and annual meeting abstracts of the American Heart Association, American College of Cardiology, and European Society of Cardiology were searched from 1996-2000. In addition, reference lists provided by the pharmaceutical industry (Glaxo Wellcome Inc.) were searched. SELECTION CRITERIA: Included were randomized placebo-controlled trials of 20 or more adult patients of either sex with symptomatic congestive heart failure who were studied for seven weeks or more. Excluded were trials in which the prevalence of atrial fibrillation was 2% or greater, or in which any arrhythmia that might compromise cardiac function or any potentially reversible cause of heart failure such as acute ischemic heart disease or myocarditis was present. DATA COLLECTION AND ANALYSIS: Articles selected from the searches described above were reviewed by one of the coauthors, and validated by staff from the central office of the Heart Collaborative Review Group in Bristol, UK. MAIN RESULTS: Eleven articles meeting the defined criteria were identified, and major endpoints of mortality, hospitalization, and clinical status, based respectively upon on 8, 4, and 10 of these selected studies, were recorded and analyzed. The data show that there is no difference in mortality between treatment and control groups, whereas digitalis therapy is associated with a lower rate of hospitalization and of clinical deterioration. REVIEWER'S CONCLUSIONS: The literature indicates that digitalis has a useful role in the treatment of patients with congestive heart failure who are in normal sinus rhythm.
In passerine birds, the periodic secretion of melatonin by the pineal organ represents an important component of the pacemaker that controls overt circadian functions. The daily phase of low melatonin secretion generally coincides with the phase of intense activity, but the precise relationship between the melatonin and the behavioral rhythms has not been studied. Therefore, we investigated in European starlings (Sturnus vulgaris) (1) the temporal relationship between the circadian plasma melatonin rhythm and the rhythms in locomotor activity and feeding; (2) the persistence of the melatonin rhythm in constant conditions; and (3) the effects of light intensity on synchronized and free-running melatonin and behavioral rhythms. There was a marked rhythm in plasma melatonin with high levels at night and/or the inactive phase of the behavioral cycles in almost all birds. Like the behavioral rhythms, the melatonin rhythm persisted for at least 50 days in constant dim light. In the synchronized state, higher day-time light intensity resulted in more tightly synchronized rhythms and a delayed melatonin peak. While all three rhythms usually assumed a rather constant phase relationship to each other, in one bird the two behavioral rhythms dissociated from each other. In this case, the melatonin rhythm retained the appropriate phase relationship with the feeding rhythm.
We assessed the correlation between the rhythm of melatonin concentration and circadian blood pressure patterns in normal and hypertensive pregnancy. Ambulatory 24-h blood pressure and blood samples every 4 h were monitored in 16 primigravidae who had shown an abnormal circadian blood pressure pattern (eight pre-eclamptic and eight normotensive) in pregnancy and 6-12 months after pregnancy. The circadian rhythm was analyzed by chronobiological measures. Eight normotensive women with maintained blood pressure rhythm served as controls. During pregnancy, melatonin concentration was significantly higher in pre-eclamptic than in normotensive women (pre-eclampsia, 29.4 +/- 1.9 pg/ml, normotensin, altered rhythm, 15.6 +/- 2.1; controls, 22.7 +/- 1.8; p < 0.001). This difference faded after pregnancy, owing to the fall observed in pre-eclampsia (11.8 +/- 3.2 pg/ml, 9.8 +/- 2.1, and 11.1 +/- 2.0, respectively; NS). The rhythm of melatonin concentration was lost in all pregnant women with loss of blood pressure rhythm. After pregnancy, normotensive women showed a reappearance of both melatonin and blood pressure rhythm, whereas pre-eclamptic women showed a reappearance of blood pressure but not melatonin rhythm. The loss of blood pressure rhythm in pregnancy is consistent with the loss of melatonin concentration rhythm. In pre-eclamptic women, the normalization of blood pressure rhythm, while melatonin rhythm remained altered, suggests a temporal or causal priority of circadian concentration of melatonin in the determination of blood pressure trend.
It is known that contemporary space station revolves at the altitude of 400-500 km in the outer space. The present study was undertaken to investigate the effects of simulated space rhythm (L:D = 0.75 h:0.75 h) at this altitude on circadian rhythm in tree shrews (Tupaia belangeri chinensis) and the effects of endogenous sleep inducing neuropeptide Asp5-alpha-DSIP on the space-rhythm-entrained circadian rhythm. This primitive stock serves as one species of Tupaiidae and is a unique native of South China. Our previous studies have shown that this species showed striking differences in natural circadian rhythm between day and night (e.g. 3.03 degrees C of rectal temperature). Results showed that the above mentioned space rhythm (L:D = 0.75h:0.75h) could drastically disturb the inherent circadian rhythm of Tupaia belangeri chinensis. The maximal peak of motor activity dropped significantly in the morning (0600-1200) and a new enhanced peak (more than 20 times greater than that of the control) was found between 1800-2400, whereas the maximal trough of motor activity (2400-0600) remained basically unchanged. Concurrently, the total amount of 24-h motor activity was significantly decreased and the recovery after the cessation of space rhythm was slow. Experimental results also demonstrated that consecutive administration of Asp5-alpha-DSIP (30 micrograms/kg, i.p.) for 5 days (2 days before and 3 days during space rhythm) did not prevent the basic disturbance of circadian rhythm of Tupaia belangeri chinensis caused by the space rhythm (L:D = 0.75h:0.75h). Nevertheless, no decrease or even some enhancement of the total amount of 24th motor activity was observed during space rhythm or after its cessation.
The daily rhythms of melatonin, cortisol and body temperature were studied in 16 institutionalized subjects with the Lennox-Gastaut syndrome. The results of 9 subjects with normal daily rhythms of sleep and wakefulness (group 1) were compared with those of 7 subjects with disordered sleep (group 2). Salivary samples were collected and axillary temperature was measured every 2 h during two or three separate 26-h periods. The hormones were measured by radioimmunoassays. The rhythms were characterized with single cosinor analysis. Two subjects in group 1 and six subjects in group 2 had abnormalities in their rhythms of temperature, cortisol or melatonin. All three rhythms were disrupted in two subjects of group 2. These two subjects were the only ones with disrupted cortisol rhythm. The diversity of rhythm pathologies suggested partly separate regulatory mechanisms for each rhythm. The co-occurrence of circadian rhythm sleep disorders with the deteriorated melatonin rhythm raised the question as to whether the sleep disorders of these subjects, like those of subjects with healthy brains, could be relieved by the induction of normal melatonin rhythm.
The desynchronaization between sleep-wakefulness rhythm and other biological rhythms such as rectal temperature rhythm and melatonin rhythm is the most unique characteristics for human circadian rhythms. Based on the findings of desynchronaization, a multi-oscillator hypothesis has been advanced for the human circadian clock. Three kind of the hypotheses such as Wever, Kronauer and two-process model were introduced in this article. According to the multi-oscillator hypothesis, one clock regulates rectal temperature and melatonin rhythm and another clock regulates sleep-wake rhythm. There are a few differences between the two different kind of circadian rhythms. For example, the oscillator mechanism which regulates the rectal temperature and the melatonin rhythm are reseted directly by the bright light, but the sleep-wake rhythm is entrained by the bright light through an internal coupling to the former mechanism. And it is also recognized that the length and the structure of sleep are depended strongly on the phase of biological clock which regulates the rectal temperature rhythm.
During organic stress, severe dysfunctions of fundamental biological phenomena, such as modification of vagal tone, have been described. These dysfunctions could induce changes in the rhythm of acid secretion and/or its hormonal control. We therefore analyzed the effects of acute respiratory failure on the 24 h variations in intragastric pH, serum gastrin, and pancreatic polypeptide levels, taken as a marker of vagal tone. Body temperature and plasma cortisol circadian rhythms were used as marker rhythms. Twelve patients with chronic obstructive pulmonary disease complicated with acute respiratory failure were studied before and during continuous enteral nutrition; half of the patients received ranitidine, a H2 blocker. During the 3 days of the study, intragastric pH was below 2.5 for only one third of the time. No difference was observed between the placebo and the ranitidine groups. Plasma pancreatic polypeptide was within normal ranges despite increased cortisol levels. Gastrin levels reflected changes in intragastric pH over the 24 h time frame and were noted to increase during ranitidine and enteral nutrition. Despite the loss of cortisol and body temperature circadian rhythmicity all throughout the study, circadian rhythms were maintained or restored during the different therapeutic regimens for intragastric pH, serum gastrin, and pancreatic polypeptide levels. Moreover, an ultradian rhythm for gastrin before any treatment, a circadian rhythm for intragastric pH on enteral nutrition, a circadian rhythm for intragastric pH, plasma gastrin and plasma pancreatic polypeptide on ranitidine regimen were observed. Thus during acute respiratory failure, certain physiological circadian rhythms persisted despite the disappearance of "marker" rhythms. Furthermore, these rhythms for digestive secretions could be pharmacologically restored.
In order to investigate the relationship between internal desynchronization and clinical intolerance to shift work, a set of circadian rhythms including salivary cortisol rhythm were monitored in seven shift-working ambulance personnel. Oral temperature, grip strength of both hands, subjective assessment of drowsiness, fatigue and attention were recorded approximately every four hours except during sleep, for seven days. Self-sampling of salivary cortisol, which was suitable evaluation of endocrine rhythm in field studies, was also tried in this study. cosinor (cosine curve fitting) method and power spectral analysis were used for time series data analysis. The internal desynchronizations between rhythms of physiological variables and sleep-wake cycle were observed in shift-working ambulance personnel. The incidence of internal desynchronization seemed to be higher in intolerant subjects, although the difference between tolerant and intolerant subjects did not reach a statistically significant level. The peak time of salivary cortisol rhythm during a twenty-four hour shift was phase-advanced as intolerant to shift work showed apparently an atypical circadian pattern of salivary cortisol with an abnormal peak at 21.00 h. In this subject, the clinical intolerance to shift work seemed to be associated with internal desynchronization of circadian rhythms. The present study confirmed the internal desynchronization of the circadian rhythm in physiological rhythms like oral temperature and grip strengths, and was in favour of the hypothesis of an internal desynchronization and clinical intolerance to shift work. The clinical implication of impairment of salivary cortisol rhythm remains to be further investigated.
In healthy mature subjects simple reaction time (SRT) to a single light signal (an easy task) is associated with a prominent rhythm with tau = 24 h of dominant (DH) as well as nondominant (NDH) hand performance, while three-choice reaction time (CRT), a complex task, is associated with tau = 24 h of the DH but tau < 24 h of the NDH. The aims of the study were to assess the influence of age and gender on the difference in tau of the NDH and DH, as it relates to the corresponding cortical hemisphere of the brain, in comparison to the rhythm in handgrip strength. Healthy subjects, 9 (5 M and 4 F) adolescents 10-16 yr of age and 15 (8 M and 7 F) adults 18-67 yr of age, active between 08:00 +/- 1 h and 23:00 +/- 1:30 h and free of alcohol, tobacco, and drug consumption volunteered. Data were gathered longitudinally at home and work 4-7 times daily for 11-20 d. At each test time the following variables were assessed: grip strength of both hands (Dynamometer: Colin-Gentile, Paris, France); single reaction time to a yellow signal (SRT); and CRT to randomized yellow, red, or green signal series with varying instruction from test to test (Psycholog-24: Biophyderm, France). Rhythms in the performance in SRT, CRT, and handgrip strength of both DH and NDH were explored. The sleep-wake rhythm was assessed by sleep-logs, and in a subset of 14 subjects it was also assessed by wrist actigraphy (Mini-Motionlogger: AMI, Ardsley NY). Exploration of the prominent period tau of time series was achieved by a special power spectra analysis for unequally spaced data. Cosinor analysis was used to quantify the rhythm amplitude A and rhythm-adjusted mean M of the power spectral analysis determined trial tau. A 24h sleep-wake rhythm was detected in almost all cases. In adults, a prominent tau of 24 h characterized the performance of the easy task by both the DH and NDH. In adults a prominent tau of 24 h was also detected in the complex CRT task performed by the DH, but for the NDH the tau was < 24 h. This phenomenon was not gender-related but was age-related since it was seldom observed in adolescent subjects. Hand-side differences in the grip strength rhythms in the same individuals were detected, the tau being ultradian rather than circadian in adolescent subjects while in mature subjects the tau frequently differed from that of the rhythm in CRT. These findings further support the hypothesis that functional biological clocks exist in both the left and right hemispheres of the human cortex.
The circadian wheel-running activity rhythms of individual hamster pups raised and maintained in constant dim light were measured beginning at 18 days of age. Records of the postweaning free-running activity rhythm were used to determine the phase of a pup's rhythm on the day of weaning and its phase relationship to its mother's rhythm. Although raised in constant light, the rhythms of pups within a litter were approximately synchronous and in phase with their mother's activity rhythm. These results indicate that the circadian oscillator underlying the activity rhythm is functional prior to weaning and is entrained by some as yet unidentified aspect of maternal rhythmicity. Furthermore, the results suggest that even in the absence of external entraining cycles, behavioral rhythms, and perhaps physiologic rhythms as well, of a mother and her offspring are normally synchronized.
The 24-hour rhythm of retinal and hypothalamic melatonin immunofluorescence was determined in male albino rats and compared to the 24-hour rhythm of serum melatonin determined by radioimmunoassay. Under a 12-hour (0:00-12:00): 12-hour dark cycle, the 24-hour rhythm of melatonin immunocytochemical fluorescence in the retina was biomodal (crests at 1:00 and 10:00-13:00). In serum, melatonin has a single crest late in the dark period (18:00). In the hypothalamus melatonin immunofluorescence showed increments corresponding to the crests in retina (13:00) and serum (18:00). In a 2-hour light: 22-hour dark cycle, the retinal rhythm was suppressed, the serum rhythm unchanged, and the hypothalamic rhythm had a single crest corresponding to the crest of the serum melatonin rhythm. These data indicate that the 24-hour hypothalamic rhythm of melatonin immunofluorescence may be secondary to the serum and retinal 24-hour rhythms of melatonin.
Circadian rhythms of flashing and glow were recorded simultaneously in Gonyaulax polyedra by determining maximum and minimum light emission at each measured interval of 28 sec. In constant light, the two rhythms in some cases showed different period lengths (tau), the glow rhythm being up to 1 hr shorter than the flashing rhythm. Lower temperatures shortened the tau of the glow rhythm more than that of the flashing rhythm. The amplitude of the flashing rhythm decreased when the temperature was increased from 15 degrees C to 25 degrees C, whereas that of the glow rhythm was increased. These results may indicate that the two rhythms are controlled by two separate oscillators.
In the subtropical finch, spotted munia (Lonchura punctulata), circanual rhythms (of gonads, fattening, feeding) have been demonstrated in an information-free environment of continuous illumination (LL), rendering it an ideal model for research on the physiology of the circannual clock. In an attempt to understand the involvement, if any, of the circadian system in the genesis of circannual rhythms, we studied the effect of pinealectomy (LL 15 lux) and strong continuous illumination (LL 300 lux), both known to abolish circadian rhythms, on the circadian perch-hopping rhythm and on the circannual rhythm of reproduction and fattening in the same birds. While both pinealectomy and LL 300 lux treatments abolished the circadian rhythm of motor activity, they had no effect on the circannual rhythms of gonadal size and fattening. If the endogenous circadian rhythm in perch-hopping can be taken to reflect the circadian clock mechanism associated with gonadal functioning, present results suggest that circannual rhythm of reproduction in spotted munia is independent of circadian events.
This paper outlines the relevance of the idea of rhythm to cultural anthropology, with specific suggestions for a medical anthropology of rhythm. By reconsidering the fluid nature of the concept of rhythm in ordinary language, the paper defines rhythm functionally in terms of a temporal order that anticipates, suspends and fulfills on the level of the visceral, physical, ecological, institutional as well as the moral. Although the paper identifies most explicitly the link between the bodily and social rhythm, it tries to suggest a cosmic background in the interaction of the social and bodily rhythms. The paper is divided into three parts: 1) the general problem of defining rhythm, 2) the concept of rhythm from its origin, and 3) the concept of rhythm in cultural theory since Durkheim. Further readings in particular reference to medical anthropology are often indicated in the notes.
OBJECTIVES: The Atrial Fibrillation Follow-up Investigation of Rhythm Management (AFFIRM) functional status substudy aimed to test the hypothesis that functional status is similar in rate-control and rhythm-control strategies. BACKGROUND: Randomized studies, including the AFFIRM study, have failed to demonstrate survival benefits between rate-control and rhythm-control strategies for atrial fibrillation (AF). However, AF may cause functional capacity or cognitive impairment that might justify maintenance of sinus rhythm. METHODS: Investigators of the AFFIRM study enrolled 4,060 patients with AF who required long-term therapy and who were 65 years of age or older or who had another risk factor for stroke or death. New York Heart Association functional class (NYHA-FC) and Canadian Cardiovascular Society Angina Classification were assessed at initial and each follow-up visit. From 22 randomly chosen functional status substudy sites, 245 participants underwent 6-min walk tests and Mini-Mental State Examination (MMSE) at initial, two-month, and yearly visits. Patients were assigned randomly to rate-controlling drugs, allowing AF to persist, or rhythm-controlling antiarrhythmic drugs, to maintain sinus rhythm. RESULTS: The NYHA-FC worsened with time in both rate-control and rhythm-control groups, with no differences between groups. Presence of AF was associated with worse NYHA-FC (p < 0.0001). No differences were observed in Canadian Cardiovascular Society Angina Classification or MMSE scores. Six-minute walk distance improved over time in both study arms. On average, walk distance was 94 feet greater in the rhythm-control group (adjusted p = 0.049). CONCLUSIONS: Modest improvement in 6-min walk distance was noted in the rhythm-control arm. Presence of AF was associated with worse NYHA-FC. No difference in cognitive function was detected.