scholarly journals PERSPECTIVE: The Long-Term Effects of Light Exposure on Establishment of Newborn Circadian Rhythm

2018 ◽  
Vol 14 (10) ◽  
pp. 1829-1830
Author(s):  
Jacqueline Yates
Keyword(s):  
Circadian Rhythm ◽  
Light Exposure ◽  
Long Term Effects

scholarly journals The Acetyltransferase CLOCK Is Dispensable for Circadian Aftereffects in Mice

2011 ◽  
Vol 26 (6) ◽  
pp. 561-564 ◽  
Author(s):  
Christian Beaulé ◽  
Hai-Ying M. Cheng
Keyword(s):  
Histone Acetyltransferase ◽  
Light Exposure ◽  
Light Cycle ◽  
Long Term Effects ◽  
Brain Physiology ◽  
Free Running ◽  
Recent Demonstration ◽  
Histone Acetyltransferase Activity

Recent demonstration of the histone acetyltransferase activity of the Clock gene greatly expanded the regulatory role of circadian clocks in gene transcription. Clock and its partner Bmal1 are responsible for the generation of circadian oscillations that are synchronized (entrained) to the external light cycle. Entraining light often produces long-lasting changes in the endogenous period called aftereffects. Aftereffects are light-dependent alterations in the speed of free-running rhythms that persist for several weeks upon termination of light exposure. How light causes such long-lasting changes is unknown. However, the persistent nature of circadian aftereffects in conjunction with the long-term effects of epigenetic modifications on development and various aspects of brain physiology prompted us to hypothesize that the histone acetyltransferase CLOCK was required for circadian aftereffects. The authors exposed Clock knockout mice to 25-hour light cycles and report that these mice retain the ability to display circadian aftereffects, indicating that Clock is dispensable for this form of circadian plasticity.

scholarly journals Circadian Dysregulation: A Mainstream Mess of the Present World

2021 ◽  
pp. 272-281
Author(s):  
Pankaj Mehta ◽  
Gurpreet Kaur ◽  
Neelam Thakur ◽  
Navneet Kaur
Keyword(s):  
Circadian Rhythm ◽  
Lung Tumor ◽  
Internal Clock ◽  
Long Term Effects ◽  
Lung Tumorigenesis ◽  
Core Components ◽  
Anxiety Depression ◽  
Present World ◽  
Circadian Rhythm Disorders

The physiological systems of humans and other organisms are periodic in nature. One such system is a circadian rhythm, a biological internal clock that is endogenous and entrainable. The circadian rhythm regulates essential functions such as the sleep/wake cycle, hormones, feeding behaviour, metabolism and cell division as well. Due to shift work or jet lag or even irregular sleep, diet, etc., circadian rhythm disorders are one of the most common problems in this century. It is a major factor that can trigger various diseases like depression, lung tumorigenesis, cancer, anxiety, depression and many more. The purpose of this review is to discuss circadian dysregulation and its potential long-term effects in cancer including lung tumor and mental illness including depression, anxiety. Loss of autonomous cells containing Bmal1 and Per2 (the core components of circadian rhythm) will increase growth and metabolism imbalance and increase in c-Myc levels. To treat circadian rhythm disorders, zeitgebers (external cues) should be used to entrain or synchronize the circadian rhythm and sleep phase chronotherapy can also be used.

Augmenting leptin circadian rhythm following a weight reduction in diet-induced obese rats: short- and long-term effects

Metabolism ◽  
2004 ◽  
Vol 53 (6) ◽  
pp. 782-789 ◽  
Author(s):  
Anne Buison ◽  
Michael Pellizzon ◽  
Frank Ordiz ◽  
K.-L.Catherine Jen
Keyword(s):  
Circadian Rhythm ◽  
Weight Reduction ◽  
Long Term Effects ◽  
Obese Rats ◽  
Short And Long Term

scholarly journals Breaking the rules: Atypical photoreceptors with diverse functions

2011 ◽  
Vol 33 (6) ◽  
pp. 6-9
Author(s):  
Catherine Sheely ◽  
Samer Hattar
Keyword(s):  
Hormonal Regulation ◽  
Light Exposure ◽  
Day Length ◽  
Food Chains ◽  
Long Term Effects ◽  
Neuronal Structure ◽  
The Earth ◽  
Unicellular Organisms ◽  
To Receive

As the Earth rotates around its axis, the Sun illuminates different parts of the planet with varied strengths and amounts of light exposure. Primary producers, from unicellular cyanobacteria to redwood trees, harness the light energy and provide the basis for food chains in the Earth's ecosystems. Light, however, has other functions that are important for survival, which include phototaxis in unicellular organisms, measuring day length (photoperiodism) in plants and animals, and vision. Although the eye is a highly specialized organ that contains the photoreceptive machinery to mediate vision, organisms such as fish, birds and lizards rely on extraocular photoreceptors to co-ordinate long-term effects of light, including synchronization of daily rhythms to the solar day, photoperiodic measurements and hormonal regulation. Mammals, however, rely solely on the eyes and a specialized photoreceptive neuronal structure, the retina, to receive all light information for image and non-image forming visual functions.

scholarly journals Chronodisruption: effects on reproduction, transgenerational health of offspring and epigenome

Reproduction ◽  
2020 ◽  
Vol 160 (5) ◽  
pp. R79-R94 ◽  
Author(s):  
Leyla Sati
Keyword(s):  
Circadian Rhythm ◽  
Human Subjects ◽  
Temporal Organization ◽  
Model Systems ◽  
Long Term Effects ◽  
Negative Effects ◽  
Reproductive Systems ◽  
Complex Biological System ◽  
Epigenetic Effects

The circadian system regulates the daily temporal organization in behavior and physiology, including neuroendocrine rhythms and reproduction. Modern life, however, increasingly impacts this complex biological system. Due to limitations of working with human subjects exposed to shift work schedules, most chronoregulation research has used rodent models. Recent publications in these model systems have emphasized the negative effects of circadian rhythm disruption on both female and male reproductive systems and fertility. Additionally, there is growing concern about the long-term effects of circadian rhythm disruptions during pregnancy on human offspring and their descendants as circadian regulation during pregnancy can also alter epigenetic programing in offspring. However, to truly know if such concerns apply to humans will require retrospective and prospective human studies. Therefore, this review will highlight the latest available evidence regarding potential effects of chronodisruption on both female and male reproductive systems. Additionally, it presents a comprehensive summary of transgenerational and epigenetic effects on adult offspring that result from maternal chronodisruption.

scholarly journals Daily blue-light exposure shortens lifespan and causes brain neurodegeneration in Drosophila

2019 ◽  
Vol 5 (1) ◽  
Author(s):  
Trevor R. Nash ◽  
Eileen S. Chow ◽  
Alexander D. Law ◽  
Samuel D. Fu ◽  
Elzbieta Fuszara ◽  
...  
Keyword(s):  
Blue Light ◽  
Prolonged Exposure ◽  
Light Exposure ◽  
Model Organism ◽  
Accelerated Aging ◽  
Health Concern ◽  
Constant Darkness ◽  
Long Term Effects ◽  
Light Emitting

Abstract Light is necessary for life, but prolonged exposure to artificial light is a matter of increasing health concern. Humans are exposed to increased amounts of light in the blue spectrum produced by light-emitting diodes (LEDs), which can interfere with normal sleep cycles. The LED technologies are relatively new; therefore, the long-term effects of exposure to blue light across the lifespan are not understood. We investigated the effects of light in the model organism, Drosophila melanogaster, and determined that flies maintained in daily cycles of 12-h blue LED and 12-h darkness had significantly reduced longevity compared with flies maintained in constant darkness or in white light with blue wavelengths blocked. Exposure of adult flies to 12 h of blue light per day accelerated aging phenotypes causing damage to retinal cells, brain neurodegeneration, and impaired locomotion. We report that brain damage and locomotor impairments do not depend on the degeneration in the retina, as these phenotypes were evident under blue light in flies with genetically ablated eyes. Blue light induces expression of stress-responsive genes in old flies but not in young, suggesting that cumulative light exposure acts as a stressor during aging. We also determined that several known blue-light-sensitive proteins are not acting in pathways mediating detrimental light effects. Our study reveals the unexpected effects of blue light on fly brain and establishes Drosophila as a model in which to investigate long-term effects of blue light at the cellular and organismal level.

Ovarian Dysfunction in Fetally Irradiated Beagles

1977 ◽  
Vol 35 ◽  
pp. 658-659
Author(s):  
T. M. Seed ◽  
M. H. Sanderson ◽  
D. L. Gutzeit ◽  
T. E. Fritz ◽  
D. V. Tolle ◽  
...  
Keyword(s):  
Gamma Rays ◽  
Low Dose ◽  
Long Term Effects ◽  
Ovarian Dysfunction ◽  
Dose Rates ◽  
Highly Sensitive ◽  
Microscopic Evaluation ◽  
Ovarian Pathology ◽  
Normal Offspring

The developing mammalian fetus is thought to be highly sensitive to ionizing radiation. However, dose, dose-rate relationships are not well established, especially the long term effects of protracted, low-dose exposure. A previous report (1) has indicated that bred beagle bitches exposed to daily doses of 5 to 35 R 60Co gamma rays throughout gestation can produce viable, seemingly normal offspring. Puppies irradiated in utero are distinguishable from controls only by their smaller size, dental abnormalities, and, in adulthood, by their inability to bear young.We report here our preliminary microscopic evaluation of ovarian pathology in young pups continuously irradiated throughout gestation at daily (22 h/day) dose rates of either 0.4, 1.0, 2.5, or 5.0 R/day of gamma rays from an attenuated 60Co source. Pups from non-irradiated bitches served as controls. Experimental animals were evaluated clinically and hematologically (control + 5.0 R/day pups) at regular intervals.

Ultrastructural investigations of MDL 19,660-induced effects on the canine platelet and megakaryocyte

1990 ◽  
Vol 48 (3) ◽  
pp. 374-375
Author(s):  
D.E. Loudy ◽  
J. Sprinkle-Cavallo ◽  
J.T. Yarrington ◽  
F.Y. Thompson ◽  
J.P. Gibson
Keyword(s):  
Antidepressant Drug ◽  
Beagle Dogs ◽  
Long Term Effects ◽  
Short Term ◽  
Platelet Counts ◽  
Toxicological Studies ◽  
Induced Aggregation ◽  
Internal Architecture

Previous short term toxicological studies of one to two weeks duration have demonstrated that MDL 19,660 (5-(4-chlorophenyl)-2,4-dihydro-2,4-dimethyl-3Hl, 2,4-triazole-3-thione), an antidepressant drug, causes a dose-related thrombocytopenia in dogs. Platelet counts started to decline after two days of dosing with 30 mg/kg/day and continued to decrease to their lowest levels by 5-7 days. The loss in platelets was primarily of the small discoid subpopulation. In vitro studies have also indicated that MDL 19,660: does not spontaneously aggregate canine platelets and has moderate antiaggregating properties by inhibiting ADP-induced aggregation. The objectives of the present investigation of MDL 19,660 were to evaluate ultrastructurally long term effects on platelet internal architecture and changes in subpopulations of platelets and megakaryocytes.Nine male and nine female beagle dogs were divided equally into three groups and were administered orally 0, 15, or 30 mg/kg/day of MDL 19,660 for three months. Compared to a control platelet range of 353,000- 452,000/μl, a doserelated thrombocytopenia reached a maximum severity of an average of 135,000/μl for the 15 mg/kg/day dogs after two weeks and 81,000/μl for the 30 mg/kg/day dogs after one week.

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