Chronobiological study on the circadian rhythm of blood gastrin in non‐synchronized young healthy males as tested by different statistical methods

Abstract

In this study, the day course of blood gastrin was investigated in a group of 15 students whose eating habits had not been synchronized. A significant 24‐h pattern could be found. Because of the discrepancy between the rhythm parameters obtained by Cosinor analysis and the visual inspection of the original data, a new method of testing the suitability of the Cosinor model was applied. On analysis of our data we came to the conclusion that the circadian rhythm of blood gastrin could have an endogenous as well as an exogenous component.     

Tumor progression as a factor of variability of diurnal rhythm of phosphorus metabolism in a tumor

In a transplanted lymphosarcoma of rats by means of Cosinor method we discovered rhythm of P32 inclusions with ultradian and circadian periods. In the course of tumor growth changes of spectrum of periods, amplitudes and acrophases of rhythms take place. These shifts are explained by the progression and clonal structure of neoplasms.     

Circadian course of delta 5,3 beta-hydroxysteroids and glucocorticosteroids in the plasma and brain of rats

Corticosterone (B), pregnenolone (P) and dehydroepiandrosterone (D) undergo circadian variations in the rat plasma and brain. When the data are interpreted by the Cosinor method, the acrophases of P in brain and of D in plasma significantly precede the acrophase of B. The asynchrony of delta 5-3 beta-hydroxysteroid and glucocorticosteroid rhythms brings an additional argument in favor of separate regulatory mechanisms.     

24-hour pattern of work-related injury risk of French firemen: nocturnal peak time

The first aim of the study was to assess clock-time patterning of work-related injuries (WRIs) of firemen (FM) of Sa?ne et Loire-71 (France) during the 4-yr span of 1 January 2004 to 31 December 2007. FM of this service are legally required to log every WRI and seek its evaluation by the medical service, whether the WRI was the result of worksite duties or exercise/sport activities at the station. WRI was defined specifically as a (nonexercise, nonsport, and nonemotional/stress) work-associated trauma, verified both by log book and medical records. For the corresponding years, the 24-h pattern of emergency calls (Calls) plus road traffic (Traffic) on the main roads of the service area was also assessed. Relative risk (R) of WRI was calculated as the quantity of WRIs/h divided by the quantity of Call responses/h?×?1000, which takes into account the number of at-risk FM/unit time, since each dispatched emergency vehicle is staffed with 4 FM. Comparably trained regular (RFM) and volunteer (VFM) FM experienced a total of 187 WRIs. The 24-h WRI curve patterns of RFM and VFM were correlated (r?=?0.4, p??.05). Analysis of variance (ANOVA) validated comparable clock-time patterns in WRIs of RFM and VFM each year and each season (all p??.0006; Cosinor analysis, p?相似文献   

Daily Modifications of 3h-Naloxone Binding Sites in the Rat Brain: A Quantitative Autoradiographic Study

The endogenous opioid peptides, the opiate receptors and several related behaviours, like opioid-mediated analgesia, show daily variations in different animal species including rats. The attempt to correlate the daily rhythm of opiate receptors in the central nervous system (CNS) to opiate related rhythmic phenomena requires an experimental approach with a high anatomical resolution, as the opioid distribution is very heterogeneous. In this paper we present the study of daily variations of 3H-naloxone binding sites in the different regions of the adult male rat brain, performed by means of quantitative autoradiography. Five rats are sacrificed at each investigated time of the day (0200, 0600,1000,1400,1800 and 2200). The ligand is 3H-naloxone(4nM), the quantification is performed by means of densitometric procedures (image analyzer Tesak VDC 501, computer Digital PDP11,3H-microscale). The statistical analysis is performed according to the single Cosinor method and the one-way analysis of variance followed by the multiple range test of Duncan. We analysed 33 different regions of the rat CNS, and the daily variations of opiate receptors are regionally selective. A circadian rhythm is found in the anterior cingulate cortex, hippocampal cortex, periventricular, medial, ventral, reticular and posterior nuclei of the thalamus, rhomboid, gelatinosus and rheuniens nuclei, lateral hypothalamus, locus coeruleus, grey substance of the pons, reticular formation of medulla oblongata, inferior olivary complex, medial part of the nucleus of the solitary tract and nucleus of the spinal tract of the trigeminal nerve. An ultradian rhythm is found in the medial and lateral preoptic areas, in the medial hypothalamus, in the medial and in the lateral nuclei of habenula. No significant variations during 24 hr according to the Cosinor analysis are found in the dorsal and lateral cerebral cortex, striatum, globus pallidus, bed nucleus of the stria terminalis, septal nuclei, lateral nucleus of the thalamus, cochlear nuclei, nucleus of the solitary tract, lateral and caudal parts, dorsal motor nucleus of the vagal nerve, XII and IX nerve nuclei. The amplitude of the daily variations observed ranges from 10 to 40%. Our results demonstrate the high anatomical selectivity of the daily modifications of 3H-naloxone binding sites in the rat CNS. They also indicate that quantitative autoradiography is a suitable and sensitive technique for these studies.     

Independence between Rhythms of Temperature and Progesterone in Mares

We investigated the ultradian and diurnal body temperature and plasma progesterone concentration rhythms and the temporal relationship between them in mares during the midluteal phase. Data were obtained from 6 mares at 3-h intervals for 3 consecutive days. Cosinor analysis showed that body temperature acrophases occurred in the evening, whereas the progesterone acrophases occurred in the early morning (3 mares) and at night (3 mares). The spectral analysis of the temperature data showed periods of 24 hr for all mares and of 8 hr for 1 mare. In contrast, the periods observed for plasma progesterone concentration were quite divergent (24 and 12 hr). The small variation in the rhythmic parameters of body temperature suggests that its oscillator system is stable. No phase relationship was detected between the rhythmometric parameters of body temperature and plasma progesterone concentration, suggesting that the physiological mechanisms of control of the 24 hr and ultradian rhythm of the two variables are not coupled during the midluteal phase.     

Independence between Rhythms of Temperature and Progesterone in Mares

We investigated the ultradian and diurnal body temperature and plasma progesterone concentration rhythms and the temporal relationship between them in mares during the midluteal phase. Data were obtained from 6 mares at 3-h intervals for 3 consecutive days. Cosinor analysis showed that body temperature acrophases occurred in the evening, whereas the progesterone acrophases occurred in the early morning (3 mares) and at night (3 mares). The spectral analysis of the temperature data showed periods of 24 hr for all mares and of 8 hr for 1 mare. In contrast, the periods observed for plasma progesterone concentration were quite divergent (24 and 12 hr). The small variation in the rhythmic parameters of body temperature suggests that its oscillator system is stable. No phase relationship was detected between the rhythmometric parameters of body temperature and plasma progesterone concentration, suggesting that the physiological mechanisms of control of the 24 hr and ultradian rhythm of the two variables are not coupled during the midluteal phase.     

24-hour pattern in lag time of response by firemen to calls for urgent medical aid

The aim of the study was to assess the group 24-h pattern of lag time (LT) in response by regular and volunteer firemen (RFM and VFM) to calls for medical help (CFMH), specifically calls for out-of-hospital cardiac arrest (OHCA). LT, duration in min between a CFMH and departure of service vehicle equipped with a semiautomated defibrillator and generally staffed with four well-trained and ready-to-go FM, represents the integrated duration of several processes, each with separate reaction and decision-making times. The exact time of each CFHM (in min, h, day, month, yr) was recorded electronically, and the exact departure time from the station of the responding FM vehicle was recorded by an on-duty FM. Overall, CFMH made up 53 ± 9% (SEM) of all emergencies calls for aid. To standardize the study methods, the reported findings are based on 568 CFMH specifically regarding OHCA that occurred during the 4-yr study span (January 2005 to December 2008). CFMH exhibited a 24-h pattern with a major peak at 10:00 h (mean ± SEM: n = 9.5 ± 1.6) and major trough at 01:00 h (n = 1.3 ± 0.3; t test, p??.05). In CFMH/h pooled time series, ANOVA-detected differences between the hourly means (p?相似文献   

Bright Light Therapy: Improved Sensitivity to Its Effects on Rest-Activity Rhythms in Alzheimer Patients by Application of Nonparametric Methods

Sleep-wake rhythm disturbances in patients with Alzheimer's disease (AD) make a strong demand on caregivers and are among the most important reasons for institutionalization. Several previous studies reported that the disturbances improve with increased environmental light, which, through the retinohypothalamic tract, activates the suprachiasmatic nucleus (SCN), the biological clock of the brain. The data of recently published positive and negative reports on the effect of bright light on actigraphically assessed rest-activity rhythms in demented elderly were reanalyzed using several statistical procedures. It was demonstrated that the light-induced improvement in coupling of the rest-activity rhythm to the environmental zeitgeber of bright light is better detected using nonparametric procedures. Cosinor, complex demodulation, and Lomb-Scargle periodogram-derived variables are much less sensitive to this effect because of the highly nonsinusoidal waveform of the rest-activity rhythm. Guidelines for analyses of actigraphic data are given to improve the sensitivity to treatment effects in future studies.     

Circadian Variation in the Occurrence of Paroxysmal Supraventricular Tachycardia in Clinically Healthy Subjects

The purpose of this study was to assess prospectively the circadian distribution of spontaneous paroxysmal Supraventricular tachycardia (PSVT) in drug-free subjects with no previous history or symptoms and signs of concomitant heart or lung disease. Of 112,424 presumably diurnally active patients admitted to the Emergency Department of a city hospital during a 2-year period (1990-1991), a total of 185 patients were screened with these characteristics. Time of symptom onset was exactly recordable in 177 (75 men and 102 women). Analysis of variance documented a higher incidence in the morning-afternoon hours. Cosinor analysis, although not a perfect method for the time series analysis, verified circadian rhythmicity with afternoon peak times. Our findings suggest that a circadian pattern in intrinsic electrical instability of the heart conduction system exists irrespective of the circadian fluctuations in the pathophysiologic mechanisms of the cardiovascular or lung diseases most frequently associated with PSVT itself.     

Cosinor analysis of diurnal changes of the reduced glutathione level in the blood, brain, liver and kidneys of mice, induced by ACTH administration

The influence of a single dose of ACTH(100 I.U. /kg body weight) on the diurnal rhythm of reduced glutathione (GSH) was studied in the blood and brain, liver and kidney homogenates of male mice. Cosinor analysis revealed that ACTH induces changes in the mean diurnal amount of GSH in the blood, brain, liver and kidneys. At the same time, GSH amplitudes in the blood and kidneys increased significantly, whereas in the case of brain and liver they decreased markedly. Moreover, it was found that ACTH induces a shift in GSH acrophases in the blood, brain, liver and kidneys as compared with the control values.     

Circadian variation of the cell proliferation in the jejunal epithelium of rats at weaning phase

Circadian variation in cell proliferation of the jejunal epithelium of 18-day-old rats was studied using the 2-h arrested metaphase score and crypt isolation method. A continuous decrease in the arrested metaphases occurred from 07.00 h to 13.00 h. From 17.00 h arrested metaphase values increased and were maintained at the higher level during the dark period as showed by Cosinor analyses (P < 0.05). These results indicate that in the young rat there is already a circadian variation in jejunal epithelial cell proliferation as early as 18 days. We can even suggest that the presence of a circadian rhythm at weaning contributes to the steady state of cell proliferation in the intestinal epithelium observed in adult life.     

Influence of actinomycin-D on the diurnal rhythm of cytoplasmic RNA in the neurocytes of selected nuclei of mouse hypothalamus

The influence of a single dose of actinomycin-D (1 mg/kg body weight) on the diurnal rhythm of cytoplasmic RNA was studied in neurocytes of the supraoptic nucleus (SON), paraventricular nucleus (PVN), and arcuate nucleus (AN) by microspectrophotometer. Cosinor analysis of the obtained results revealed a disturbed diurnal rhythm of cytoplasmic RNA in the animals treated with actinomycin-D. The mean diurnal RNA content in the SON, PVN, and AN neurocytes decreased, the amplitude of diurnal fluctuation was reduced and the acrophase was shifted to earlier hours.     

Spatiotemporal variability in activity patterns of urban street cattle as function of environmental factors

ABSTRACT

In the current study, we studied behavioral patterns, such as foraging, activity, standing, and laying in a population of cattle wandering on streets of Raipur city. We also determined the effects of four environmental factors (temperature, humidity, light, and noise intensities) on these behaviors. We recorded all four behavioral variables at four time points each day over a period of three consecutive days at 10 randomly selected locations using on-site human observation method, digital video, and still camera. We used Cosinor rhythmometry to analyze the time series data on all four behavioral variables. One-way ANOVA was performed to determine the impact of the factor “time of the day” on all observed behavioral variables. Pearson correlation was also employed to evaluate the relationship between the environmental and behavioral variables. Cosinor analyses revealed statistically significant 24-h rhythms in all observed behavioral variables, at the group level, with peaks of foraging, activity, standing, and laying located at 11.54 h, 14.54 h, 18.66 h, and 23.88 h, respectively. Factor “time of the day” had statistically significant effect on all observed behavioral variables. Foraging and activity were found to be positively correlated with temperature, light, and noise intensities; and negatively correlated with humidity. The laying behavior was found to be negatively associated with temperature, light, and noise intensities; and positively correlated with humidity. The findings of this study might be helpful in the management of cattle menace that has become an annoying phenomenon on the streets and highways of almost all Indian cities.     

Circadian rhythm changes in toxicity of the insecticide dieldrin on larvae of the migratory locust Locusta migratoria migratorioides.

Circadian changes in toxicity of the insecticide dieldrin were documented in the larvae (fifth stage) of the migratory locust, Locusta migratoria migratorioides. Insects were housed under light (L): dark (D) = 12:12, with L from 0800 to 2000 h. Topical applications of dieldrin at fixed clock hours, with doses ranging from 0.1 to 8 micrograms/gm body weight, were carried out in a series of experiments on male and female larvae. Twenty-four h after dosing, mortality was recorded to quantify the median lethal dose (LD50) values with reference to time of treatment. Experiments were performed during February, early and late June, and August. Larvae were more susceptible to dieldrin when dosed during the night rather than during the day [analysis of variance (ANOVA); p less than 0.05]. Moreover, female larvae were less susceptible to dieldrin than were male larvae (ANOVA; p less than 0.05). Cosinor analysis revealed circadian rhythms in susceptibility-resistance to the insecticide in all experiments except no. 2. Toxicity was found to be greatest during the nighttime. Cosinor analysis of pooled data of the four experiments documented circadian rhythmicity to toxicity of dieldrin in female but not in male larvae. Regardless of sex, the timing of least susceptibility (greatest resistance and highest LD50 value) to the insecticide, dieldrin, was around 1500.     

24-hour Pattern in Lag Time of Response by Firemen to Calls for Urgent Medical Aid

The aim of the study was to assess the group 24-h pattern of lag time (LT) in response by regular and volunteer firemen (RFM and VFM) to calls for medical help (CFMH), specifically calls for out-of-hospital cardiac arrest (OHCA). LT, duration in min between a CFMH and departure of service vehicle equipped with a semiautomated defibrillator and generally staffed with four well-trained and ready-to-go FM, represents the integrated duration of several processes, each with separate reaction and decision-making times. The exact time of each CFHM (in min, h, day, month, yr) was recorded electronically, and the exact departure time from the station of the responding FM vehicle was recorded by an on-duty FM. Overall, CFMH made up 53?±?9% (SEM) of all emergencies calls for aid. To standardize the study methods, the reported findings are based on 568 CFMH specifically regarding OHCA that occurred during the 4-yr study span (January 2005 to December 2008). CFMH exhibited a 24-h pattern with a major peak at 10:00?h (mean?±?SEM: n?=?9.5?±?1.6) and major trough at 01:00?h (n?=?1.3?±?0.3; t test, p?<?.001). From year to year and season to season, a 24-h pattern was detected in the total of CFMH/h with two peaks (～10:00 and ～17:00h) and two troughs (～01:00 and ～15:00?h) (analysis of variance [ANOVA], p?<?.01; Cosinor, p?<?.05 to?<?.003), with neither season- nor year-related differences (χ², p?>?.05). In CFMH/h pooled time series, ANOVA-detected differences between the hourly means (p?<?.01), and Cosinor analysis validated a 24-h rhythm (p?<?.002). In raw data, the longest LT, indicative of poorest performance, occurred at 05:00?h (8.8?±?0.7?min) and the trough of LT, indicative of best performance, at 16:00?h (4.3?±?0.8?min (t test, p?<?.02). 24-h patterning in LT was validated both by ANOVA of hourly means (p?<?.0006) and Cosinor analysis (p?<?.05), with longest LT ～05:00?h and shortest LT ～16.00?h for data of the individual yearly time-series data. The 24-h LT rhythm was also validated in the pooled time series by Cosinor (p?<?.0001), with the 24-h mean?±?SEM?=?6?±?0.17?min and acrophase (peak) of 03:00?h?±?88?min (SD). Curve patterns of CFMH/h and LT/h differed widely. As a group phenomenon, the LT 24-h rhythm mimics the 24-h pattern of performance, as demonstrated by many laboratory and field investigations. The stability of the LT rhythm between years and seasons and its weak relationship with the CFMH 24-h pattern favors the hypothesis of an endogenous component or origin. The nighttime trough of performance is presumably linked to the elevated risk of work accidents in the same population of FM.     

24-Hour Pattern of Work-Related Injury Risk of French Firemen: Nocturnal Peak Time

The first aim of the study was to assess clock-time patterning of work-related injuries (WRIs) of firemen (FM) of Saône et Loire-71 (France) during the 4-yr span of 1 January 2004 to 31 December 2007. FM of this service are legally required to log every WRI and seek its evaluation by the medical service, whether the WRI was the result of worksite duties or exercise/sport activities at the station. WRI was defined specifically as a (nonexercise, nonsport, and nonemotional/stress) work-associated trauma, verified both by log book and medical records. For the corresponding years, the 24-h pattern of emergency calls (Calls) plus road traffic (Traffic) on the main roads of the service area was also assessed. Relative risk (R) of WRI was calculated as the quantity of WRIs/h divided by the quantity of Call responses/h?×?1000, which takes into account the number of at-risk FM/unit time, since each dispatched emergency vehicle is staffed with 4 FM. Comparably trained regular (RFM) and volunteer (VFM) FM experienced a total of 187 WRIs. The 24-h WRI curve patterns of RFM and VFM were correlated (r?=?0.4, p?<?.05), with no histogram difference (p?>?.05). Analysis of variance (ANOVA) validated comparable clock-time patterns in WRIs of RFM and VFM each year and each season (all p?<?.0001). Thus, time series of the RFM and VFM were pooled, revealing a statistical significant 24-h variation in WRIs (ANOVA, p?>?.0006; Cosinor analysis, p?<?.0001), with peak at 16:00?h and trough at 04:00?h. The 24-h pattern in Traffic, which mirrors that of human activity, with peak ～18:00?h and trough ～03:00?h, was also verified (ANOVA, p <?.0001; Cosinor, p?<?.0001). Calls (n?=?112,059) resulting in FM responses also exhibited statistically significant 24-h variation, with peak at ～20:00?h and trough at ～06:00?h. The 24-h pattern of R showed a nocturnal peak at 02:00?h (R?=?2.87?±?0.46; mean?±?SEM) and diurnal trough 14:00?h (R?=?1.30?±?0.05) (t test, p?<?.02); clock-time-related changes in R were further validated by ANOVA (p?=?.0001) and Cosinor (p?<?.0001), with acrophase (peak time, Ø) of 02:43?h?±?68?min (SD). The second aim of the study was to evaluate the relationship between the 24-h patterns of WRIs and lag-time (LT) response (used as a measure of work performance) of FM of the same service to urgent medical calls for out-of-hospital cardiac arrests. Highest R of WRI at 02:00?h corresponded closely to longest LT (raw data at ～02:00?h and Cosinor derived Ø of 02.54?h?±?71?min [SD]), thereby supporting the hypothesis of a common mechanism underlying the two 24-h profiles. A third aim was to determine the relevance of a new concept in work safety, “chronoprevention,” for future FM training programs. (Author correspondence: bergarein@yahoo.fr)     

Seeking Tau in Head Injury

The aim of this study was to determine if heart rate, blood pressure (diastolic, systolic, and mean), intracranial pressure, and cerebral perfusion pressure of patients with head injury have circadian rhythm. We studied data of 13 patients with severe head injury using the Iterative Cosinor method. We detected a circadian rhythm for at least one of the parameters in 11 (85%) of the 13 patients. The period of the rhythms (tau) was often not equal to 24 hours. Also, taus within and between patients were different. The results of our study showed that in these patients, when parameters are recorded hourly, tau can be estimated reasonably accurately (average error 0.7 hours). The distribution of taus suggests that the patients in our sample had free-running circadian rhythm. We used the surrogate data technique to validate the results of our study. Possible reasons for uncertainty in tau-estimation and proposed changes in data collection protocols and inclusion criteria are discussed.