Temperature profiles, and the effect of sleep on them, in relation to morningness-eveningness in healthy female subjects

There were 15 healthy female subjects, differing in their position on the “morningness-eveningness” scale, studied for 7 consecutive days, first while living a sedentary lifestyle and sleeping between midnight and 08:00 and then while undergoing a “constant routine.” Rectal temperature was measured at regular intervals throughout this time, and the results were subjected to cosinor analysis both before and after “purification” for the effects of physical activity. Results showed that there was a phase difference in the circadian rhythm of core temperature that was associated with the morningness score, with calculations that “morning types” would be phased earlier than “evening types” by up to about 3h. This difference in phase (which was also statistically significant when the group was divided by a median split into a “morning group” and an “evening group”) could not be attributed to effects of waking activity and existed in spite of the subjects keeping the same sleep-wake schedule. Moreover, it persisted when the subjects' data had been purified and when the data were obtained from the constant routine. That is, there was an endogenous component to this difference in phase of the core temperature. The morning group also showed a greater fall of core temperature during sleep; this was assessed in two ways, the main one being a comparison of constant routine and nychthemeral data sets after correction for any effects of activity. Even though the morning group was sleeping at a later phase of their circadian temperature rhythm than was the evening group, neither group showed a fall of temperature due to sleep that varied with time elapsed since the temperature acrophase. It is concluded that another factor that differs between morning and evening types is responsible for this difference. (Chronobiology International, 18(2), 227-247, 2001)     

Role of intracellular reactive oxygen species and mitochondrial dysfunction in evening primrose extract-induced apoptosis in Ehrlich ascites tumor cells

Herbal medicines are increasingly being utilized to treat a wide variety of disease processes. Evening primrose extract (EPE) is extracted from Oenothera biennis L., one species of evening primroses, which has been shown to have several pharmacological effects. However, anti-tumor activity in the extract of defatted seeds of O. biennis L. has not been defined thus far. In this study, we identified the major biochemical changes upon EPE treatment and investigated the functional relationship between these changes. We found that EPE-induced apoptosis in Ehrlich ascites tumor cells as evidenced by morphological changes. Furthermore, our results demonstrated rapid increase of intracellular peroxides levels, loss of mitochondrial membrane potential and the release of cytochrome c from mitochondria to cytosol. These results suggest that the rapid increase of intracellular peroxides levels after addition of EPE triggers off induction of apoptosis.     

Chronopharmacology of Captopril plus Hydrochlorothiazide in Hypertension: Morning Versus Evening Dosing

Blood pressure follows a strong circadian rhythm in normotensive people and in patients with primary hypertension. This may have several implications for antihypertensive therapy, including the time of dosing. For this reason we studied the influence of different dosing times on the antihypertensive effect over 24 h using ambulatory blood pressure monitoring (ABPM). We studied 13 male patients with moderate hypertension with controlled blood pressure over 12 months under a fixed combination of captopril and hydrochlorothiazide. The dosage of the combination therapy was then halved and given as one evening and then as one morning dose, each for 3 weeks. The combination therapy given twice daily showed a good 24-h antihypertensive effect after 12 months of treatment. During the following 6 weeks the mean 24-h blood pressure did not increase under half dosage, irrespective of whether under evening or morning dosing. However, mean daytime values (systolic and diastolic) of ABPM were significantly higher with evening dosing when compared both with full dosage and with half dosage given in the morning. The mean arterial blood pressure over 24 h showed the same differences as systolic and diastolic blood pressure, whereas heart rate was not significantly different between the three therapeutic regimens. ABPM seems to be an ideal method for chronopharmacological investigations under everyday conditions. Our study demonstrated significant differences in daytime blood pressure but not in 24-h blood pressure between morning and evening dosing of a fixed antihypertensive combination therapy.     

Possible evidence for morning and evening oscillators in Drosophila melanogaster populations selected for early and late adult emergence

In this paper, we report the results of our study aimed at a systematic analysis of the circadian phenotypes of fruit flies Drosophila melanogaster selected for early and late adult emergence, in light of the "morning and evening oscillator" (M and E) model for circadian clocks. We monitored adult emergence and activity/rest rhythms in these flies under light/dark (LD) cycles with short (8:16 h), normal (12:12 h) and long (16:8 h) photoperiods, as well as under constant darkness (DD). Across all the three LD cycles, the early populations displayed a morning phenotype with peak of emergence and activity occurring earlier than the controls and greater anticipation to "lights-on" and weak anticipation to "lights-off", while the late populations showed an evening phenotype with peak of emergence and activity occurring later than the controls and greater anticipation to lights-off and weak anticipation to lights-on. The gate of adult emergence and duration of activity in the early populations was narrower than the controls, while those of the late populations were wider than the controls. In addition, the circadian periodicities of adult emergence and activity/rest rhythms of the early flies were significantly shorter than the controls, while those of the late flies were significantly longer than the controls. In summary, the circadian phenotypes indicate that the early populations have evolved a dominant M oscillator, while the late populations have evolved a dominant E oscillator, thus providing an empirical support for the M and E model in Drosophila.     

Involvement of polyamines in evening primrose extract-induced apoptosis in Ehrlich ascites tumor cells

Summary. We previously demonstrated that evening primrose extract (EPE) induced apoptosis and inhibited the DNA synthesis in Ehrlich ascites tumor cells (EATC) and suggested that EPE-induced inhibition of the growth of EATC are via at least two pathway differentially modulated by reactive oxygen species, notably intracellular peroxides. These are (a) the EPE-induced apoptosis pathway which is dependent on increases in hydrogen peroxide and (b) the EPE-induced inhibition of cell proliferation which is hydrogen peroxide independent. In this study, EPE brought about a significant decrease in intracellular polyamine levels. Furthermore, the addition of polyamines reversed the EPE-induced decrease in cell viability and suppressed the EPE-induced increase in intracellular hydrogen peroxides. However, the addition of polyamines did not reverse EPE-induced decrease in DNA synthesis and phosphorylation of Rb protein, and EPE-induced translocation of AIF. These results suggest the involvement of polyamines in the EPE-induced apoptosis pathway which is dependent on increase in hydrogen peroxide.     

Associations between chronotypes and psychological vulnerability factors of depression

Chronotypes have been associated with psychopathology. The eveningness chronotype has been consistently linked with depressed states or depressive disorder, but the underlying mechanism remains unclear. Prior studies have shown associations between chronotype and personality traits that are linked to depression (e.g. neuroticism), but other psychological vulnerability factors have not been previously investigated in relation to chronotypes. The aim of this study was to examine the association between chronotypes, depression and psychological risk factors of depression (namely, cognitive reactivity and worry), in a large cohort of depressed patients and healthy individuals. We used data from the Netherlands Study of Depression and Anxiety (n = 1654), which includes 1227 clinically diagnosed individuals with a lifetime diagnosis of depression and 427 healthy controls. We assessed cognitive reactivity (Leiden Index of Depression Sensitivity-Revised) and trait worry (Penn State Worry Questionnaire). We controlled for sociodemographic factors as well as for insomnia and neuroticism. We found that the evening type is associated with higher cognitive reactivity scores, especially with increased rumination. Cognitive reactivity also mediated the relationship between chronotype and depression status, even when controlling for neuroticism and insomnia. Trait worry was not associated with chronotype. Our findings show that depressogenic cognitions are more prevalent in evening types and perhaps mediate the association between chronotype and depression. Further prospective research is needed to determine the timeline of the association. Nevertheless, results imply that targeting depressogenic cognitive processes, perhaps in combination with chronotherapeutic treatments, may be particularly useful in evening types.     

Lutein-based plumage coloration in songbirds is a consequence of selective pigment incorporation into feathers

Many birds obtain colorful carotenoid pigments from the diet and deposit them into growing tissues to develop extravagant red, orange or yellow sexual ornaments. In these instances, it is often unclear whether all dietary pigments are used as integumentary colorants or whether certain carotenoids are preferentially excluded or incorporated into tissues. We examined the carotenoid profiles of three New World passerines that display yellow plumage coloration—the yellow warbler (Dendroica petechia), common yellowthroat (Geothlypis trichas) and evening grosbeak (Coccothraustes vespertinus). Using high-performance liquid chromatography, we found that all species used only one carotenoid—lutein—to color their plumage yellow. Analyses of blood carotenoids (which document those pigments taken up from the diet) in two of the species, however, revealed the presence of two dietary xanthophylls—lutein and zeaxanthin—that commonly co-occur in plants and animals. These findings demonstrate post-absorptive selectivity of carotenoid deposition in bird feathers. To learn more about the site of pigment discrimination, we also analyzed the carotenoid composition of lipid fractions from the follicles of immature yellow-pigmented feathers in G. trichas and D. petechia and again detected both lutein and zeaxanthin. This suggests that selective lutein incorporation in feathers is under local control at the maturing feather follicle.     

Melatonin ingestion after exhaustive late-evening exercise improves sleep quality and quantity,and short-term performances in teenage athletes

ABSTRACT

The present study aimed to explore the effects of a single 10-mg dose of melatonin (MEL) administration after exhaustive late-evening exercise on sleep quality and quantity, and short-term physical and cognitive performances in healthy teenagers. Ten male adolescent athletes (mean ± SD, age = 15.4 ± 0.3 years, body-mass = 60.68 ± 5.7 kg, height = 167.9 ± 6.9 cm and BMI = 21.21 ± 2.5) performed two test sessions separated by at least one week. During each session, participants completed the Yo-Yo intermittent-recovery-test level-1 (YYIRT-1) at ~20:00 h. Then, sleep polysomnography was recorded from 22:15 min to 07:00 h, after a double blind randomized order administration of a single 10-mg tablet of MEL (MEL-10 mg) or Placebo (PLA). The following morning, Hooper wellness index was administered and the participants performed the Choice Reaction Time (CRT) test, the Zazzo test and some short-term physical exercises (YYIRT-1, vertical and horizontal Jumps (VJ; HJ), Hand grip strength (HG), and five-jump test (5-JT)). Evening total distance covered in the YYIRT-1 did not change during the two conditions (p > 0.05). Total sleep time (Δ = 24.55 mn; p < 0.001), sleep efficiency (Δ = 4.47%; p < 0.001), stage-3 sleep (N3 sleep) (Δ = 1.73%; p < 0.05) and rapid-eye-movement sleep (Δ = 2.15%; p < 0.001) were significantly higher with MEL in comparison with PLA. Moreover, sleep-onset-latency (Δ = –8.45mn; p < 0.001), total time of nocturnal awakenings after sleep-onset (NA) (Δ = –11 mn; p < 0.001), stage-1 sleep (N1 sleep) (Δ = –1.7%; p < 0.001) and stage-2 sleep (N2 sleep) (Δ = ?1.9%; p < 0.05) durations were lower with MEL. The Hooper index showed a better subjective sleep quality, a decrease of the subjective perception of fatigue and a reduced level of muscle soreness with MEL. Moreover, MEL improved speed and performance but not inaccuracy during the Zazzo test. CRT was faster with MEL. Morning YYIRT-1 (Δ = 82 m; p < 0.001) and 5-JT (Δ = 0.08 m; p < 0.05) performances were significantly higher with MEL in comparison with PLA. In contrast, HG, VJ and HJ performances did not change during the two conditions (p > 0.05). The administration of a single dose of MEL-10 mg after strenuous late-evening exercise improved sleep quality and quantity, selective attention, subjective assessment of the general wellness state, and some short-term physical performances the following morning in healthy teenagers.