Browsing by Subject "circadian rhythm"

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  • Cannistraci, Carlo Vittorio; Nieminen, Tuomo; Nishi, Masahiro; Khachigian, Levon M.; Viikilä, Juho; Laine, Mika; Cianflone, Domenico; Maseri, Attilio; Yeo, Khung Keong; Bhindi, Ravinay; Ammirati, Enrico (2018)
    Background-ST-elevation acute myocardial infarction (STEMI) represents one of the leading causes of death. The time of STEMI onset has a circadian rhythm with a peak during diurnal hours, and the occurrence of STEMI follows a seasonal pattern with a salient peak of cases in the winter months and a marked reduction of cases in the summer months. Scholars investigated the reason behind the winter peak, suggesting that environmental and climatic factors concur in STEMI pathogenesis, but no studies have investigated whether the circadian rhythm is modified with the seasonal pattern, in particular during the summer reduction in STEMI occurrence. Methods and Results-Here, we provide a multiethnic and multination epidemiological study (from both hemispheres at different latitudes, n= 2270 cases) that investigates whether the circadian variation of STEMI onset is altered in the summer season. The main finding is that the difference between numbers of diurnal (6:00 to 18:00) and nocturnal (18:00 to 6:00) STEMI is markedly decreased in the summer season, and this is a prodrome of a complex mechanism according to which the circadian rhythm of STEMI time onset seems season dependent. Conclusions-The "summer shift" of STEMI to the nocturnal interval is consistent across different populations, and the sunshine duration (a measure related to cloudiness and solar irradiance) underpins this season-dependent circadian perturbation. Vitamin D, which in our results seems correlated with this summer shift, is also primarily regulated by the sunshine duration, and future studies should investigate their joint role in the mechanisms of STEMI etiogenesis.
  • Puttonen, Eetu; Lehtomäki, Matti; Litkey, Paula; Näsi, Roope; Feng, Ziyi; Liang, Xinlian; Wittke, Samantha; Pandzic, Milos; Hakala, Teemu; Karjalainen, Mika; Pfeifer, Norbert (Frontiers Reseach Foundation, 2019)
    Frontiers in Plant Science
    Terrestrial Laser Scanning (TLS) can be used to monitor plant dynamics with a frequency of several times per hour and with sub-centimeter accuracy, regardless of external lighting conditions. TLS point cloud time series measured at short intervals produce large quantities of data requiring fast processing techniques. These must be robust to the noise inherent in point clouds. This study presents a general framework for monitoring circadian rhythm in plant movements from TLS time series. Framework performance was evaluated using TLS time series collected from two Norway maples (Acer platanoides) and a control target, a lamppost. The results showed that the processing framework presented can capture a plant's circadian rhythm in crown and branches down to a spatial resolution of 1 cm. The largest movements in both Norway maples were observed before sunrise and at their crowns' outer edges. The individual cluster movements were up to 0.17 m (99th percentile) for the taller Norway maple and up to 0.11 m (99th percentile) for the smaller tree from their initial positions before sunset.
  • Immonen, Katariina (Helsingin yliopisto, 2022)
    Aims of the study. The aim of this study was to examine normative development of sleep patterns and circadian rhythmicity during adolescence. Previous studies have found that sleep duration shortens across the lifespan, and especially adolescents’ sleep timing shifts later due to physiological and psychological factors. Sleep patterns in adolescence are connected to individual’s endogenous circadian rhythms, usually measured by delayed melatonin secretion in the evening. There is a lack of understanding how sleep patterns are related to circadian body temperature rhythms during adolescence. Methods. This study was part of SleepHelsinki! cohort study of the Sleep & Mind Research Group. Adolescents’ sleep patterns were measured with actigraphies, whereas circadian body temperature was measured from the skin surface. Circadian temperature rhythmicity was inspected by circadian period length, the mesor of skin surface temperature and the amplitude of daily changes within the rhythm. Baseline measurements were measured from 215 (71.6 % girls) adolescents aged 16–18 years. At one-year follow-up, 156 (76.3 % girls) adolescents were measured again. Mixed models for repeated measures were used to examine changes over the year in sleep patterns and endogenous circadian temperature rhythm, separately for both girls and boys. Sex differences were tested with one-way variance analysis. Linear and ordinal regressions were used to predict sleep and circadian rhythm over the year. Results and conclusions. Over the year, adolescents’ sleep duration became longer during the week, while weekend sleep shortened. However, this change was only significant for girls. Sleep schedule became more delayed for both girls and boys during the week, as sleep onset, midpoint and offset occurred at a later time. Circadian rhythm changed for boys, as their average skin surface temperature increased, and their circadian temperature amplitude became smaller. Boys also had significantly lower circadian temperature amplitude than girls at the follow-up. Compared to boys, girls were 5.85 times more likely to have a high circadian temperature amplitude at the follow-up measurement. Changes in sleep length during the week was moderated by temperature amplitude, with higher circadian amplitude predicting sleep duration to become longer. Still, the likelihood to have long sleep duration was affected by past sleep duration.
  • Hemmann, Karin; Raekallio, Marja; Kanerva, Kira; Hänninen, Laura; Pastell, Matti; Palviainen, Mari; Vainio, Outi (2012)
    Crib-biting is classified as an oral stereotypy, which may be initiated by stress susceptibility, management factors, genetic factors and gastrointestinal irritation. Ghrelin has been identified in the gastric mucosa and is involved in the control of food intake and reward, but its relationship to crib-biting is not yet known. The aim of this study was to examine the concentration and circadian variation of plasma ghrelin, cortisol, adrenocorticotropic hormone (ACTH) and β-endorphin in crib-biting horses and non-crib-biting controls. Plasma samples were collected every second hour for 24 h in the daily environment of eight horses with stereotypic crib-biting and eight non-crib-biting controls. The crib-biting horses had significantly higher mean plasma ghrelin concentrations than the control horses. The circadian rhythm of cortisol was evident, indicating that the sampling protocol did not inhibit the circadian regulation in these horses. Crib-biting had no statistically significant effect on cortisol, ACTH or β-endorphin concentrations. The inter-individual variations in β-endorphin and ACTH were higher than the intra-individual differences, which made inter-individual comparisons difficult and complicated the interpretation of results. Further research is therefore needed to determine the relationship between crib-biting and ghrelin concentration.
  • Molari, Joonas (Helsingin yliopisto, 2018)
    Currently, there is an undeniable need for more effective treatments of depression. The efficacy of traditional antidepressant drugs becomes apparent after multiple weeks of treatment. New advancements in depression treatments have been made, as glutamatergic NMDA-receptor antagonist ketamine is seen to ameliorate symptoms rapidly, even only hours after drug administration. Understanding ketamine’s mechanism of action as an antidepressant could enable the development of more effective antidepressant drugs. The critical molecular level component in ketamine’s antidepressant effect is considered to be the activation of TrkB tyrosine receptor kinase B, which subsequently leads to the initiation of signaling pathways, which regulate synaptic plasticity. So far, it has not been examined; whether there is a difference in ketamine’s antidepressant effect based on the dosing-time of day. The aim of the present study was to find out if there is a variation between ketamine’s effect on synaptic plasticity and the circadian phase in which the drug is administered. Ketamine’s (200 or 50 mg/kg, i.p.) effects were studied in C57BL/6J–mice during light phase (mouse’s inactive phase) and dark phase (mouse’s active phase) of the day. The phase of the day didn’t affect the activity of TrkB signaling in its related parts (pTrkBTyr816, pGSK3βSer9, p-p70S6KTyr421/Ser424 and p-p44/42MAPKThr202/Tyr204) in prefrontal cortex samples which were analysed in Western blot assay. Ketamine increased dose-dependently the phosphorylation of GSK3βSer9 and p70S6KTyr421/Ser424 as well as decreased p-p44/42MAPKThr202/Tyr204 at 30 minutes after drug administration in both phases of the day. Ketamine (200 mg/kg, i.p.) also lowered the glucose concentration measured from the trunk blood. To examine the effect of hypoglycemia on the activity of TrkB signaling another experiment was conducted. The hypoglycemia induced by insulin detemir (6 IU/kg, i.p.) didn’t affect any measured protein phosphorylation at 60 minutes after drug administration. The results of this study support the notion of ketamine’s rapid and dosedependent induction of neuroplasticity. The possible role of hypoglycemia in ketamine's neuropharmacology should be investigated in future studies.
  • Pesonen, Anu-Katriina; Merikanto, Ilona; Halonen, Risto; Ujma, Peter; Makkonen, Tommi; Räikkönen, Katri; Lahti, Jari; Kuula, Liisa (2020)
    Sleep spindles are thalamocortical oscillations that contribute to sleep maintenanceand sleep-related brain plasticity. The current study is an explorative study of the cir-cadian dynamics of sleep spindles in relation to a polygenic score (PGS) for circadianpreference towards morningness. The participants represent the 17-year follow-upof a birth cohort having both genome-wide data and an ambulatory sleep electroen-cephalography measurement available (N= 154, Mean age = 16.9, SD = 0.1 years,57% girls). Based on a recent genome-wide association study, we calculated a PGSfor circadian preference towards morningness across the whole genome, including354 single-nucleotide polymorphisms. Stage 2 slow (9-12.5 Hz,N= 186 739) andfast (12.5-16 Hz,N= 135 504) sleep spindles were detected using an automatedalgorithm with individual time tags and amplitudes for each spindle. There was a sig-nificant interaction of PGS for morningness and timing of sleep spindles across thenight. These growth curve models showed a curvilinear trajectory of spindle ampli-tudes: those with a higher PGS for morningness showed higher slow spindle ampli-tudes in frontal derivations, and a faster dissipation of spindle amplitude in centralderivations. Overall, the findings provide new evidence on how individual sleep spin-dle trajectories are influenced by genetic factors associated with circadian type. Thefinding may lead to new hypotheses on the associations previously observedbetween circadian types, psychiatric problems and spindle activity.
  • Tahkamo, Leena; Partonen, Timo; Pesonen, Anu-Katriina (2019)
    Light is necessary for life, and artificial light improves visual performance and safety, but there is an increasing concern of the potential health and environmental impacts of light. Findings from a number of studies suggest that mistimed light exposure disrupts the circadian rhythm in humans, potentially causing further health impacts. However, a variety of methods has been applied in individual experimental studies of light-induced circadian impacts, including definition of light exposure and outcomes. Thus, a systematic review is needed to synthesize the results. In addition, a review of the scientific evidence on the impacts of light on circadian rhythm is needed for developing an evaluation method of light pollution, i.e., the negative impacts of artificial light, in life cycle assessment (LCA). The current LCA practice does not have a method to evaluate the light pollution, neither in terms of human health nor the ecological impacts. The systematic literature survey was conducted by searching for two concepts: light and circadian rhythm. The circadian rhythm was searched with additional terms of melatonin and rapid-eye-movement (REM) sleep. The literature search resulted to 128 articles which were subjected to a data collection and analysis. Melatonin secretion was studied in 122 articles and REM sleep in 13 articles. The reports on melatonin secretion were divided into studies with specific light exposure (101 reports), usually in a controlled laboratory environment, and studies of prevailing light conditions typical at home or work environments (21 studies). Studies were generally conducted on adults in their twenties or thirties, but only very few studies experimented on children and elderly adults. Surprisingly many studies were conducted with a small sample size: 39 out of 128 studies were conducted with 10 or less subjects. The quality criteria of studies for more profound synthesis were a minimum sample size of 20 subjects and providing details of the light exposure (spectrum or wavelength; illuminance, irradiance or photon density). This resulted to 13 qualified studies on melatonin and 2 studies on REM sleep. Further analysis of these 15 reports indicated that a two-hour exposure to blue light (460 nm) in the evening suppresses melatonin, the maximum melatonin-suppressing effect being achieved at the shortest wavelengths (424 nm, violet). The melatonin concentration recovered rather rapidly, within 15 min from cessation of the exposure, suggesting a short-term or simultaneous impact of light exposure on the melatonin secretion. Melatonin secretion and suppression were reduced with age, but the light-induced circadian phase advance was not impaired with age. Light exposure in the evening, at night and in the morning affected the circadian phase of melatonin levels. In addition, even the longest wavelengths (631 nm, red) and intermittent light exposures induced circadian resetting responses, and exposure to low light levels (5-10 lux) at night when sleeping with eyes closed induced a circadian response. The review enables further development of an evaluation method of light pollution in LCA regarding the light-induced impacts on human circadian system.
  • Sokolowska, Ewa; Viitanen, Riikka; Misiewicz, Zuzanna; Mennesson, Marie; Saarnio, Suvi; Kulesskaya, Natalia; Kängsep, Sanna; Liljenback, Heidi; Marjamäki, Paivi; Autio, Anu; Callan, Saija-Anita; Nuutila, Pirjo; Roivainen, Anne; Partonen, Timo; Hovatta, Iiris (2021)
    Cryptochrome 2 (Cry2) is a core clock gene important for circadian regulation. It has also been associated with anxiety and depressive-like behaviors in mice, but the previous findings have been conflicting in terms of the direction of the effect. To begin to elucidate the molecular mechanisms of this association, we carried out behavioral testing, PET imaging, and gene expression analysis of Cry2(-/-) and Cry2(+/+) mice. Compared to Cry2(+/+) mice, we found that Cry2(-/-) mice spent less time immobile in the forced swim test, suggesting reduced despair-like behavior. Moreover, Cry2(-/-) mice had lower saccharin preference, indicative of increased anhedonia. In contrast, we observed no group differences in anxiety-like behavior. The behavioral changes were accompanied by lower metabolic activity of the ventro-medial hypothalamus, suprachiasmatic nuclei, ventral tegmental area, anterior and medial striatum, substantia nigra, and habenula after cold stress as measured by PET imaging with a glucose analog. Although the expression of many depression-associated and metabolic genes was upregulated or downregulated by cold stress, we observed no differences between Cry2(-/-) and Cry2(+/+) mice. These findings are consistent with other studies showing that Cry2 is required for normal emotional behavior. Our findings confirm previous roles of Cry2 in behavior and extend them by showing that the effects on behavior may be mediated by changes in brain metabolism.