Light exposure regulates several circadian functions in normal humans including the sleep-wake cycle. Individuals with Alzheimer’s Disease (AD) often do not have regular patterns of activity and rest, but, rather, experience random periods of sleep and agitation during both day and night. Bright light during the day and darkness at night has been shown to consolidate activity periods during the...

BACKGROUND The objective of this epidemiological study was to evaluate the effect of length of sunlight exposure on interleukin 6 (IL-6) levels in depressive and non-depressive subjects. METHODS This was a cross-sectional study with 154 subjects (54 males, mean age: 43.5 ± 12.8 years) who were living in a rural area in south Brazil. Chronobiological and light parameters were assessed using th...

Reduced exposure to daytime sunlight and increased exposure to electrical lighting at night leads to late circadian and sleep timing [1-3]. We have previously shown that exposure to a natural summer 14 hr 40 min:9 hr 20 min light-dark cycle entrains the human circadian clock to solar time, such that the internal biological night begins near sunset and ends near sunrise [1]. Here we show that th...

background: hairdressers are occupationally exposed to a number of agents in their workplace that result in respiratory symptoms and changes in pulmonary function. objective: to evaluate associations between occupational exposure and respiratory function and reported symptoms in a group of hairdressers compared to a control group. methods: a questionnaire on respiratory symptoms and workplace c...

The purpose of this review is to summarize the peer-reviewed literature in relation to sunlight exposure assessment and the validity of using sunlight exposure questionnaires to quantify vitamin D status. There is greater variability in personal ultraviolet (UV) light exposure as the result of personal behavior than as the result of ambient UV light exposure. Although statistically significant,...

PURPOSE Visible light has been previously demonstrated to induce retinal ganglion cell (RGC)-5 cell death through the mitochondrial pathway. The present study was designed to determine whether visible light might also directly trigger the death pathway by damaging nuclear DNA. METHODS RGC-5 cells were exposed to various intensities and durations of visible light exposure. Cell viability and d...

conclusions caffeic acid treatment reduced bacterial growth and resulted in a decreased number of colony formation. the simultaneous effect of caffeic acid and laser at three time courses showed a synergic effect in reducing colony formation compared to the control and caffeic acid, and laser alone. objectives the aim of this study was to investigate the effect of caffeic acid and low-power las...

We evaluated the effect of exposure to constant light started at the age of 1 month and at the age of 14 months on the survival, life span, tumorigenesis and age-related dynamics of antioxidant enzymes activity in various organs in comparison to the rats maintained at the standard (12:12 light/dark) light/dark regimen. We found that exposure to constant light started at the age of 1 month accel...

PURPOSE To further test the hypothesis that light-adaptation-mediated photoreceptor protection works through inhibition of apoptosis by activation and/or upregulation of neuroprotective molecules. METHODS Albino rats were born and raised in 5-lux cyclic light (12 hours OFF and ON). At 8 weeks of age, animals were adapted to 400-lux cyclic light for different periods. Light damage was induced ...

At present, light pollution (exposure to light-at-night) both in the form of occupational exposure during night work and as a personal choice and life style, is experienced by numerous night-active members of our society. Disruption of the circadian rhythms induced by light pollution has been associated with cancer in humans. There are epidemiological evidences of increased breast and colon can...