scholarly journals A Programmable Optical Stimulator for the Drosophila Eye

2017 ◽  
Author(s):  
Xinping Chen ◽  
Walter D. Leon-Salas ◽  
Taylor Zigon ◽  
Donald Ready ◽  
Vikki Weake
Keyword(s):  
Light Intensity ◽  
Retinal Degeneration ◽  
Power Density ◽  
Blue Light ◽  
Temperature Control ◽  
Light Exposure ◽  
Red Light ◽  
Photoreceptor Cells ◽  
Embedded Computer ◽  
Age Related

AbstractA programmable optical stimulator for Drosophila eyes is presented. The target application of the stimulator is to induce retinal degeneration in fly photoreceptor cells by exposing them to light in a controlled manner. The goal of this work is to obtain a reproducible system for studying age-related changes in susceptibility to environmental ocular stress. The stimulator uses light emitting diodes and an embedded computer to control illuminance, color (blue or red) and duration in two independent chambers. Further, the stimulator is equipped with per-chamber light and temperature sensors and a fan to monitor light intensity and to control temperature. An ON/OFF temperature control implemented on the embedded computer keeps the temperature from reaching levels that will induce the heat shock stress response in the flies. A custom enclosure was fabricated to house the electronic components of the stimulator. The enclosure provides a light-impermeable environment that allows air flow and lets users easily load and unload fly vials. Characterization results show that the fabricated stimulator can produce light at illuminances ranging from 0 to 16000 lux and power density levels from 0 to 7.2 mW/cm2 for blue light. For red light the maximum illuminance is 8000 lux which corresponds to a power density of 3.54 mW/cm2. The fans and the ON/OFF temperature control are able to keep the temperature inside the chambers below 28.17°C. Experiments with white-eye male flies were performed to assess the ability of the fabricated simulator to induce blue light-dependent retinal degeneration. Retinal degeneration is observed in flies exposed to 8 hours of blue light at 7949 lux. Flies in a control experiment with no light exposure show no retinal degeneration. Flies exposed to red light for the similar duration and light intensity (8 hours and 7994 lux) do not show retinal degeneration either. Hence, the fabricated stimulator can be used to create environmental ocular stress using blue light. Specifications table

scholarly journals Chemical Exacerbation of Light-induced Retinal Degeneration in F344/N Rats in National Toxicology Program Rodent Bioassays

2016 ◽  
Vol 44 (6) ◽  
pp. 892-903 ◽  
Author(s):  
Haruhiro Yamashita ◽  
Mark J. Hoenerhoff ◽  
Shyamal D. Peddada ◽  
Robert C. Sills ◽  
Arun R. Pandiri
Keyword(s):  
Retinal Degeneration ◽  
Light Exposure ◽  
Photoreceptor Cells ◽  
Environmental Chemicals ◽  
Albino Rats ◽  
National Toxicology Program ◽  
Kava Kava ◽  
Age Related ◽  
Microscopic Evaluation ◽  
Leucomalachite Green

Retinal degeneration due to chronic ambient light exposure is a common spontaneous age-related finding in albino rats, but it can also be related to exposures associated with environmental chemicals and drugs. Typically, light-induced retinal degeneration has a central/hemispherical localization whereas chemical-induced retinal degeneration has a diffuse localization. This study was conducted to identify and characterize treatment-related retinal degeneration in National Toxicology Program rodent bioassays. A total of 3 chronic bioassays in F344/N rats (but not in B6C3F1/N mice) were identified that had treatment-related increases in retinal degeneration (kava kava extract, acrylamide, and leucomalachite green). A retrospective light microscopic evaluation of the retinas from rats in these 3 studies showed a dose-related increase in the frequencies of retinal degeneration, beginning with the loss of photoreceptor cells, followed by the inner nuclear layer cells. These dose-related increased frequencies of degenerative retinal lesions localized within the central/hemispherical region are suggestive of exacerbation of light-induced retinal degeneration.

scholarly journals The Effects of Day Length and Light Intensity on Tile Growth of Barley

1969 ◽  
Vol 22 (1) ◽  
pp. 53 ◽  
Author(s):  
D Aspinall
Keyword(s):  
Light Intensity ◽  
Linear Relationship ◽  
Light Source ◽  
Blue Light ◽  
Floral Development ◽  
Red Light ◽  
Day Length

The acceleration of flowering in barley due to the inclusion of incandescent illumination in the light source has been shown to be due to the far�red content of the light. A linear relationship between floral development and intensity of far�red light in a 16�hr photoperiod has been established with the cultivar CI5611. Barley appears to be relatively unresponsive to blue light, however.

scholarly journals Protective Effect of Astaxanthin on Blue Light Light-Emitting Diode-Induced Retinal Cell Damage via Free Radical Scavenging and Activation of PI3K/Akt/Nrf2 Pathway in 661W Cell Model

Marine Drugs ◽  
2020 ◽  
Vol 18 (8) ◽  
pp. 387 ◽  
Author(s):  
Chao-Wen Lin ◽  
Chung-May Yang ◽  
Chang-Hao Yang
Keyword(s):  
Antioxidant Enzymes ◽  
Free Radical ◽  
Protective Effect ◽  
Blue Light ◽  
Nuclear Translocation ◽  
Light Exposure ◽  
Cell Damage ◽  
Radical Scavenging ◽  
Photoreceptor Cells ◽  
Light Emitting

Light-emitting diodes (LEDs) are widely used and energy-efficient light sources in modern life that emit higher levels of short-wavelength blue light. Excessive blue light exposure may damage the photoreceptor cells in our eyes. Astaxanthin, a xanthophyll that is abundantly available in seafood, is a potent free radical scavenger and anti-inflammatory agent. We used a 661W photoreceptor cell line to investigate the protective effect of astaxanthin on blue light LED-induced retinal injury. The cells were treated with various concentrations of astaxanthin and then exposed to blue light LED. Our results showed that pretreatment with astaxanthin inhibited blue light LED-induced cell apoptosis and prevented cell death. Moreover, the protective effect was concentration dependent. Astaxanthin suppressed the production of reactive oxygen species and oxidative stress biomarkers and diminished mitochondrial damage induced by blue light exposure. Western blot analysis confirmed that astaxanthin activated the PI3K/Akt pathway, induced the nuclear translocation of Nrf2, and increased the expression of phase II antioxidant enzymes. The expression of antioxidant enzymes and the suppression of apoptosis-related proteins eventually protected the 661W cells against blue light LED-induced cell damage. Thus, our results demonstrated that astaxanthin exerted a dose-dependent protective effect on photoreceptor cells against damage mediated by blue light LED exposure.

scholarly journals Light Stress-Induced Increase of Sphingosine 1-Phosphate in Photoreceptors and Its Relevance to Retinal Degeneration

2019 ◽  
Vol 20 (15) ◽  
pp. 3670 ◽  
Author(s):  
Ryo Terao ◽  
Megumi Honjo ◽  
Takashi Ueta ◽  
Hideru Obinata ◽  
Takashi Izumi ◽  
...  
Keyword(s):  
Retinal Degeneration ◽  
Photoreceptor Cell ◽  
Light Exposure ◽  
Outer Nuclear Layer ◽  
Light Stress ◽  
Age Related Macular Degeneration ◽  
Lipid Mediator ◽  
Age Related ◽  
Sphingosine 1 Phosphate

Sphingosine 1-phosphate (S1P) is a potent lipid mediator that modulates inflammation and angiogenesis. In this study, we investigated the possible involvement of S1P in the pathology of light-induced retinal degeneration in vivo and in vitro. The intracellular S1P and sphingosine kinase (SphK) activity in a photoreceptor cell line (661W cells) was significantly increased by exposure to light. The enhancement of SphK1 expression was dependent on illumination, and all-trans-retinal significantly promoted SphK1 expression. S1P treatment reduced protein kinase B (Akt) phosphorylation and increased the protein expression of cleaved caspase-3, and induced photoreceptor cell apoptosis. In vivo, light exposure enhanced the expression of SphK1 in the outer segments of photoreceptors. Intravitreal injection of a SphK inhibitor significantly suppressed the thinning of the outer nuclear layer and ameliorated the attenuation of the amplitudes of a-waves and b-waves of electroretinograms during light-induced retinal degeneration. These findings imply that light exposure induces the synthesis of S1P in photoreceptors by upregulating SphK1, which is facilitated by all-trans-retinal, causing retinal degeneration. Inhibition of this enhancement may be a therapeutic target of outer retinal degeneration, including age-related macular degeneration.

Photodynamic Therapy for Head and Neck Cancer Xenografts in Athymic Mice

1986 ◽  
Vol 95 (5) ◽  
pp. 602-606 ◽  
Author(s):  
James H. Hill ◽  
Randall L. Plant ◽  
David M. Harris ◽  
Randal C. Paniello
Keyword(s):  
Photodynamic Therapy ◽  
Light Intensity ◽  
Head And Neck ◽  
Treatment Time ◽  
Light Exposure ◽  
Red Light ◽  
Human Head ◽  
Athymic Mice ◽  
Squamous Cancer ◽  
Argon Dye Laser

This study examines efficacy and optimal treatment variables of photodynamic therapy (PDT) for human head and neck squamous cancer (HNSC) xenografts in athymic mice. Two and four days after injection of hematoporphyrin derivative (HPD), tumors were illuminated with red light from an argon-dye laser. Sixty-three tumors were treated. With HPD dose and light intensity constant at 7.5 mg/kg and 100 mW/cm2, respectively, the extent of tumor necrosis was strongly dependent on duration of light exposure. There was no substantial difference in results for 30- and 60-minute treatment durations between animals injected with HPD 2 and 4 days before treatment. After 30 minutes treatment time, responses were seen in 8 of 10 mice (2 days post-HPD) and 11 of 12 mice (4 days post-HPD). After 60 minutes treatment time, toxicity was high. We conclude that, in this model, PDT is effective in selective killing of HNSC. For future comparison studies in this model, if the indicated HPD dose and light intensity are used we recommend a 2-day delay after HPD injection and a light exposure duration of 30 minutes

scholarly journals Effects of Changes in Colored Light on Brain and Calf Muscle Blood Concentration and Oxygenation

2011 ◽  
Vol 11 ◽  
pp. 1216-1225
Author(s):  
J. Weinzirl ◽  
M. Wolf ◽  
P. Heusser ◽  
M. Nelle ◽  
U. Wolf
Keyword(s):  
Blue Light ◽  
Blood Volume ◽  
Near Infrared ◽  
Light Exposure ◽  
Red Light ◽  
Light Therapy ◽  
Calf Muscle ◽  
Sequential Order ◽  
Color Changes ◽  
The Brain

Color light therapy is a therapeutic method in complementary medicine. In color therapy, light of two contrasting colors is often applied in a sequential order. The aim of this study was to investigate possible physiological effects, i.e., changes in the blood volume and oxygenation in the brain and calf muscle of healthy subjects who were exposed to red and blue light in sequential order. The hypothesis was that if a subject is first exposed to blue and then red light, the effect of the red light will be enhanced due to the contrastingly different characteristics of the two colors. The same was expected for blue light, if first exposing a subject to red and then to blue light. Twelve healthy volunteers (six male, six female) were measured twice on two different days by near-infrared spectroscopy during exposure to colored light. Two sequences of colored light were applied in a controlled, randomized, crossover design: first blue, then red, and vice versa. For the brain and muscle, the results showed no significant differences in blood volume and oxygenation between the two sequences, and a high interindividual physiological variability. Thus, the hypothesis had to be rejected. Comparing these data to results from a previous study, where subjects were exposed to blue and red light without sequential color changes, shows that the results of the current study appear to be similar to those of red light exposure. This may indicate that the exposure to red light was preponderant and thus effects of blue light were outweighed.

scholarly journals ANALISIS WARNA CAHAYA LAMPU TERHADAP HASIL TANGKAPAN IKAN

2012 ◽  
Vol 6 (1) ◽  
pp. 47-49
Author(s):  
Grace Loupatty
Keyword(s):  
Light Intensity ◽  
Blue Light ◽  
Wave Length ◽  
Red Light ◽  
Green Light ◽  
Yellow Light ◽  
Know How ◽  
Observation Method ◽  
Parameter Condition ◽  
Direct Observation Method

By learning and researching the wave-length of light and its propagation we can make an observation of the function and effectiveness light as a stimulation in fishing.The purposes of the observation are: to know how the color of light lamp influences to the result of fishing; to observe how the depth of location for fishing influences the reduction of light intensity; to know what is the relation between parameter condition/ atmosphere (salinity, temperature and transparency of the water) with the result of fishing.The observation is applied with a direct observation method in water of Batu Dua- Ambon Island.The total result of fishing is 57.2 kilograms with applied for us different light lamp (red, yellow, green and blue). Each color applied has the result: the red light lamps got amount of 4.5 kg; the yellow light lamps got amount of 15,1 kg ; the green light lamps got amount 17.4 kg; and the blue light lamps got amount of 20.2 kg.Data analysis statistically using an analysis of variance system which indicates that the stimulation light lamp influences to the result of fishing.Result of the statistical observation shows that parameter conditions/ atmosphere in the water, such as salinity. temperature, transparency of the water, such as: salinity, temperature, transparency of the water do not influence to the result of fishing.

Spindle shaped bodies in foveolar cones of the baboon retina

1989 ◽  
Vol 47 ◽  
pp. 960-961
Author(s):  
W. Krebs ◽  
I. Krebs
Keyword(s):  
Cross Sections ◽  
Inclusion Bodies ◽  
Photoreceptor Cells ◽  
Papio Anubis ◽  
Retinal Photoreceptor ◽  
Age Related ◽  
Cone Cells ◽  
Membrane Bound ◽  
Oriented Parallel ◽  
Shaped Inclusion

Various inclusion bodies occur in vertebrate retinal photoreceptor cells. Most of them are membrane bound and associated with phagocytosis or they are age related residual bodies. We found an additional inclusion body in foveal cone cells of the baboon (Papio anubis) retina.The eyes of a 15 year old baboon were fixed by immersion in cacodylate buffered glutaraldehyde (2%)/formaldehyde (2%) as described in detail elsewhere . Pieces of retina from various locations, including the fovea, were embedded in epoxy resin such that radial or tangential sections could be cut.Spindle shaped inclusion bodies were found in the cytoplasm of only foveal cones. They were abundant in the inner segments, close to the external limiting membrane (Fig. 1). But they also occurred in the outer fibers, the perikarya, and the inner fibers (Henle’s fibers) of the cone cells. The bodies were between 0.5 and 2 μm long. Their central diameter was 0.2 to 0. 3 μm. They always were oriented parallel to the long axis of the cone cells. In longitudinal sections (Figs. 2,3) they seemed to have a fibrous skeleton that, in cross sections, turned out to consist of plate-like (Fig.4) and tubular profiles (Fig. 5).

Nighttime Blue Light Exposure and Breast Cancer

2021 ◽  
pp. 30-33
Author(s):  
David Jaynes ◽  
Paul Switzer
Keyword(s):  
Breast Cancer ◽  
Risk Factor ◽  
Blue Light ◽  
Shift Work ◽  
Light Exposure ◽  
Night Shift ◽  
Background Information ◽  
Common Disease ◽  
Essential Information ◽  
Night Shift Work

The purpose of this article is to provide background information and the current understanding of a less familiar cause of female breast cancer; exposure to ultraviolet light at night. Breast cancer is a common disease that causes significant morbidity and mortality in women. There are several risk factors for breast cancer, most of which are genetic and environmental in nature. An often-overlooked risk factor is exposure to blue light during night shift work, which decreases melatonin production. One of the many cancer-preventing properties of melatonin is to limit estrogen production. Increased lifetime exposure to estrogen is a well-known cause of breast cancer. Awareness of nighttime blue light exposure as a breast cancer risk factor by women doing night shift work and those exposed to nighttime light via smartphones and laptops, is essential information to know so that protective measures can be taken.

scholarly journals Phototropin 1 and dim-blue light modulate the red light de-etiolation response

2014 ◽  
Vol 9 (11) ◽  
pp. e976158
Author(s):  
Yihai Wang ◽  
Kevin M Folta
Keyword(s):  
Blue Light ◽  
Red Light
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