AI Article Synopsis
Article Abstract
This study was carried out to examine the seasonal difference in the magnitude of the suppression of melatonin secretion induced by exposure to light in the late evening. The study was carried out in Akita (39 degrees North, 140 degrees East), in the northern part of Japan, where the duration of sunshine in winter is the shortest. Ten healthy male university students (mean age: 21.9+/-1.2 yrs) volunteered to participate twice in the study in winter (from January to February) and summer (from June to July) 2004. According to Japanese meteorological data, the duration of sunshine in Akita in the winter (50.5 h/month) is approximately one-third of that in summer (159.7 h/month). Beginning one week prior to the start of the experiment, the level of daily ambient light to which each subject was exposed was recorded every minute using a small light sensor that was attached to the subject's wrist. In the first experiment, saliva samples were collected every hour over a period of 24 h in a dark experimental room (<15 lux) to determine peak salivary melatonin concentration. The second experiment was conducted after the first experiment to determine the percentage of melatonin suppression induced by exposure to light. The starting time of exposure to light was set 2 h before the time of peak salivary melatonin concentration detected in the first experiment. The subjects were exposed to light (1000 lux) for 2 h using white fluorescent lamps (4200 K). The percentage of suppression of melatonin by light was calculated on the basis of the melatonin concentration determined before the start of exposure to light. The percentage of suppression of melatonin 2 h after the start of exposure to light was significantly greater in winter (66.6+/-18.4%) than summer (37.2+/-33.2%), p<0.01). The integrated level of daily ambient light from rising time to bedtime in summer was approximately twice that in winter. The results suggest that the increase in suppression of melatonin by light in winter is caused by less exposure to daily ambient light.
Download full-text PDF |
Source |
|---|---|
| http://dx.doi.org/10.1080/07420520601139805 | DOI Listing |
Publication Analysis
Top Keywords
Similar Publications
Time series (ARIMA) as a tool to predict the temperature-humidity index in the dairy region of the northern desert of Mexico.
PeerJ
December 2024
Departamento de Ciencias Médico Veterinarias, Universidad Autónoma Agraria Antonio Narro, Unidad Laguna, Torreón, Coahuila, Mexico.
The environment in which an animal is situated can have a profound impact on its health, welfare, and productivity. This phenomenon is particularly evident in the case of dairy cattle, then, in order to quantify the impact of ambient temperature (°C) and the relative humidity (%) on dairy cattle, the temperature-humidity index (THI) is employed as a metric. This indicator enables the practical estimation of the stress imposed on cattle by ambient temperature and humidity.
View Article and Find Full Text PDFThe direct and urinary electrolyte-mediated effects of ambient temperature on population blood pressure: A causal mediation analysis.
Environ Int
December 2024
Division of Epidemiology, Biostatistics, and Environmental Health, School of Public Health, The University of Memphis, Memphis, TN, USA. Electronic address:
High ambient heat can directly influence blood pressure (BP) through the vasodilation of the skin vasculature and indirectly by affecting urinary volume and electrolyte levels. We evaluated the direct and urine electrolyte-mediated effects of ambient temperature on BP. We pooled 5,624 person-visit data from a community-based stepped-wedge randomized control trial in southwest coastal Bangladesh from December 2016 to May 2017.
View Article and Find Full Text PDFA Compensated Clock: Temperature and Nutritional Compensation Mechanisms Across Circadian Systems.
Bioessays
December 2024
Department of Molecular & Systems Biology, Geisel School of Medicine at Dartmouth, Hanover, New Hampshire, USA.
Circadian rhythms are ∼24-h biological oscillations that enable organisms to anticipate daily environmental cycles, so that they may designate appropriate day/night functions that align with these changes. The molecular clock in animals and fungi consists of a transcription-translation feedback loop, the plant clock is comprised of multiple interlocking feedback-loops, and the cyanobacterial clock is driven by a phosphorylation cycle involving three main proteins. Despite the divergent core clock mechanisms across these systems, all circadian clocks are able to buffer period length against changes in the ambient growth environment, such as temperature and nutrients.
View Article and Find Full Text PDFShort-term exposure to outdoor nitrogen dioxide and respiratory mortality, with high-risk populations: a nationwide time-stratified case-crossover study.
BMC Public Health
December 2024
School of Biomedical Convergence Engineering, College of Information and Biomedical Engineering, Pusan National University, 49-Budandaehak-Ro, Yangsan, Gyeongsangnam-do, South Korea.
Numerous existing studies reported the negative impacts of outdoor nitrogen dioxide (NO) on respiratory mortality. However, the evidence of related high-risk populations was considerably limited, especially associated with ages, causes of death, and district-level characteristics. In addition, most earlier studies were based on monitored areas, thus previous risk estimates of NO could be biased to provide nationwide risk estimates and high-risk populations.
View Article and Find Full Text PDFAssociations between airborne algae, ambient air pollution and lung function in a cross-sectional canadian population-based study.
Environ Res
December 2024
Environmental Health Science & Research Bureau, Health Canada, Canada. Electronic address:
Airborne algae have been associated with respiratory illness in the setting of coastal harmful algae blooms but little is known about their effects in urban populations distributed across a country, and whether ambient air pollution is an effect modifier. Using cross-sectional data from 11,256 participants of the Canadian Health Measures Survey (CHMS), we tested the association between lung function expressed as a forced expiratory volume (FEV) and airborne concentrations of algae measured by a rotation impact sampler in the participant's city of residence on the day of spirometric testing. The daily upper 95th percentiles of algae ranged from 12.
View Article and Find Full Text PDFWant AI Summaries of new PubMed Abstracts delivered to your In-box?
Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!