Y Touitou

..Other drugs like B12 vitamin or psychotropic drugs have also been proposed as chronobiotics...

..1-1.6). Other studies are required to confirm these results...

..Melatonin also has free radical-scavenging properties that have primarily been observed in vitro at pharmacological concentrations...

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..It is unlikely that malignancies or mood disorders reported by people exposed to 50/60-Hz EMF could be related to the disruption of the melatonin levels...

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..These results suggest that age (older than 60 years), disease and male sex are associated with increased morning serum cortisol levels in a Chinese population...

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..Large-scale studies, implying numerous countries, carried on at present within the framework of the WHO should bring elements of answer to the unresolved questions...

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..The purpose of this review is to summarize the results obtained on the circadian rhythms of body temperature and motor activity throughout the daily cycle in order to clarify the relationships between these two functions...

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..This study shows that, by contrast to the pineal gland, melatonin in Wistar rat Harderian gland does not exhibit daily variations and that aging does not affect the melatonin content of the gland...

..The observed variations in metabolism parameters underline the need for study designs in pharmaco-toxicology taking into account the possible risks induced by circadian changes, especially in aged subjects...

..Our results suggest that light per se may regulate ALA-S gene expression in the rat HGs, and reveal that the ALA-S gene expression, and so heme biosynthesis, is under a photodynamic control...

..Yields of cortisol and cortisone were also large showing that the tissues did not lack the zona fasciculata-like 11 beta-hydroxylation ability...

..The question thus arises as to the origin of these alterations, and whether they are related to a cause or a consequence of the disease, and their possible incidence upon therapeutic designs...

..Our results suggest that the pineal tetrapeptide Ala-Glu-Asp-Gly, does not seem to play a role, at least in vitro, in the control of melatonin secretion by the rat pineal gland...

..CTE, and not duration estimation, was disturbed in patients. RH patients made significantly more pathological advance errors than LH patients (43% vs. 12%). This study points out the RH dominance for CTE in stroke patients...

..Additionally, melatonin, a pineal gland hormone produced from serotonin, is of special interest in autistic disorder given reported alterations in central and peripheral serotonin neurobiology...

..Light general anesthesia itself impairs synchronization of the circadian rest-activity rhythm to local time in patients by acting directly on the circadian clock...

..Overall, the sleep of this sample of Parisian children around 10 years of age was rather stable in its duration and timing, suggesting flexibility to adjust to the different school schedules...

..The purpose of this study was to investigate and compare the effects of the beta-adrenergic agonist, isoproterenol, on induced increase in melatonin production in the pineal gland of young and old rats, at different circadian stages...

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..No significant difference was found among the three younger groups, but nocturnal melatonin levels were significantly lower in the men in their 60s...

..Our data show that the circadian rhythm of motor activity, but not of body temperature, responds age dependently to a photoperiod reduction...

..These data show that daytime fasting, modifications in sleep schedule and psychological and social habits during Ramadan induce changes in the rhythmic pattern of a number of hormonal variables...

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..8. CONCLUSION: Our study demonstrates that changes in the characteristics of the circadian rhythm of serum leptin in healthy men are associated with both advancing age and increased BMI...

..At the concentrations used, ghrelin does not influence melatonin production in rat pineal and Harderian glands, and therefore is not involved in the regulation of melatonin secretion, at least under our experimental conditions...

..Our data, which strongly suggest that prolonged mild hypoxia alters the expression of cortisol circadian rhythm, should be taken into account to interpret secretory rhythm changes after transmeridian flights...

..The results also show that the control of melatonin production in the Harderian glands differ from that observed in the pineal gland...

..This topic is highly relevant to clinicians, especially those involved in that field of ambulatory practice responsible for post-operative patient care, including patient recovery and fatigue...

..Our study clearly shows that these hormones can be considered to be stable markers of the circadian time structure and therefore useful tools to validate rhythms' synchronisation of human subjects...

..The data are of interest for the diagnosis and treatment of chronobiological disorders in prepubertal children...

..This work shows that DHEA-S (and not DHEA) is able, at pharmacological concentrations, to stimulate melatonin production by rat pineal glands regardless of the age of the animals...

..This is a rare and unusual case of adrenal pathology showing that a deficiency in 11 beta-hydroxylase activity does not rule out the presence of an adrenocortical adenoma...

..These data indicate that anticipation of social defeat induces a marked activation of cortical CCKergic neurons associated with anxiety-related behaviors in rats...

..In this study, we examined the secretion of melatonin during 24 h after a 30-min propofol anesthesia in rats...

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..The concepts of chronopharmacology and chronotoxicology are of equal importance to the fields of occupational medicine and industry medicine...

..Our findings suggest that hypoxia may by itself contribute at least in part to postflight fatigue after long duration flights, and to the clinical disorders of jet lag in transmeridian flights through its effects on the circadian system...

..Therefore, the authors conclude that mild hypobaric hypoxia does not seem to be responsible for any quantitative changes during long-haul flights in the immune assays commonly used in routine clinical medicine practice...

..In this paper we show that NPY concentrations in the rat atrium exhibit daily variations, which are maintained with ageing. Moreover, photoperiod greatly influences NPY levels in the atrium...

..Studies of ethanol's effects on TSH carried out during the daytime, when its secretion is at its nadir, do not reflect the true action of alcohol on TSH secretion since TSH peak occurs at night...

..No significant changes in amplitude or 24 h mean concentration were seen, but significant shifts of 5 h 30 min in peak and trough serum leptin levels were found on the twenty-third day of Ramadan...

..Mild hypoxia may therefore alter circadian structure and result in sleep disturbances. These results may explain in part the frequent complaints of prolonged post-flight fatigue after long flights, even when no time zones are crossed...

..This rhythmicity seems to be a pertinent criterion for alcohol dependence syndrome...

..Continuous light exposure abolishes the day-night ALA-S variation in the HG that is observed under standard 12 L:12 D conditions. Our results suggest that melatonin and environmental lighting regulate ALA-S gene expression in the rat HG...

..The authors examined whether general (propofol) anesthesia can impact the circadian temporal structure by disturbing circadian rest-activity and body temperature rhythms under normal light-dark conditions (light-dark 12:12 h) in rats...

..Resveratrol behaved as an antioxidant during the dark span and as a pro-oxidant during the light span. These data suggested a day/night rhythm in basal lipoperoxidation and in resveratrol antioxidant effect...

..We thus documented the daily and overnight variations of urinary electrolytes (calcium, magnesium, and phosphorus), urea, and creatinine in prepubertal (Tanner stage I) boys...

..The fact that diazepam affects locomotor activity, but not core body temperature, suggests that different mechanisms mediate the actions of diazepam on locomotor activity and on core body temperature...

..Finally, though the observed biochemical changes were significant, their clinical relevance must be clarified in studies involving actual long-distance flights...

..We found no significant effects of hypoxia on the circadian profile of the gonadal axis hormones and, therefore, conclude that these hormones do not serve as valuable markers of post-flight alterations of the circadian system in human...

..Our data show that the 900 MHz EMF exposure, at least under our experimental conditions, does not appear to affect endocrine functions in men...

..This study suggests that the clinical relevance of cortisol circadian rhythm for patient outcome may differ according to the hormonal dependency of the tumor...

..Such 24h rhythm alterations appeared to be independent of conventional clinical factors...

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..Also, the results are in good accordance with a modified two-oscillator model where lights-off triggers advances of an evening oscillator and lights-on delays a morning oscillator...

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..In conclusion, our results show that ANP concentrations in the rat atrium exhibit daily variations which are significantly affected by the daylength (photoperiod) change in aged rats...