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https://www.readbyqxmd.com/read/28612282/probing-of-peripheral-blood-mononuclear-cells-anchoring-on-tnf-alpha-challenged-vascular-endothelia-in-an-in-vitro-model-of-the-retinal-microvascular
#1
Yuan Li, Yao Lu, Qiong Chen, Yuejun Kang, Ling Yu
Retinopathy is a complication of diabetes that affects the eyes; it stems from damage to the microvasculature of the retina and eventually compromises vision. The diagnosis of retinopathy is difficult to make because there are no early symptoms or warning signs. Dysfunction of the retina's microvascular networks is believed to be associated with inflammatory cytokines and tumor necrosis factor alpha (TNF-α). To investigate the effect of these cytokines, such as TNF-α, a polydimethylsiloxane (PDMS)/glass hydride microfluidic device reflecting the physiological structure of the retina's microvasculature was developed...
September 2017: Biomedical Microdevices
https://www.readbyqxmd.com/read/28611460/chlorophyll-derivatives-enhance-invertebrate-red-light-and-ultraviolet-phototaxis
#2
Andrea Degl'Innocenti, Leonardo Rossi, Alessandra Salvetti, Attilio Marino, Gabriella Meloni, Barbara Mazzolai, Gianni Ciofani
Chlorophyll derivatives are known to enhance vision in vertebrates. They are thought to bind visual pigments (i.e., opsins apoproteins bound to retinal chromophores) directly within the retina. Consistent with previous findings in vertebrates, here we show that chlorin e6 - a chlorophyll derivative - enhances photophobicity in a flatworm (Dugesia japonica), specifically when exposed to UV radiation (λ = 405 nm) or red light (λ = 660 nm). This is the first report of chlorophyll derivatives acting as modulators of invertebrate phototaxis, and in general the first account demonstrating that they can artificially alter animal response to light at a behavioral level...
June 13, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28575952/biocompatibility-and-neurotoxicity-of-magnesium-alloys-potentially-used-for-neural-repairs
#3
Jianjun Fei, Xiaoxiao Wen, Xiao Lin, Saijilafu, Weihua Wang, Olga Ren, Xinjian Chen, Lili Tan, Ke Yang, Huilin Yang, Lei Yang
Nerve injury, especially the large-size nerve damage, is a serious problem affecting millions of people. Entubulation of two ends of the injured nerve by using an implantable device, e.g., nerve guidance conduit (NGC), to guide the regeneration of nerve tissue is a promising approach for treating the large-size nerve defect. Magnesium (Mg) and its alloys are biodegradable, conductive, and own good mechanical properties. Mg(2+) ion, one of the main degradation products of Mg and its alloys, was reported to promote the proliferation of neural stem cells and their neurite production...
September 1, 2017: Materials Science & Engineering. C, Materials for Biological Applications
https://www.readbyqxmd.com/read/28566464/activation-of-ganglion-cells-and-axon-bundles-using-epiretinal-electrical-stimulation
#4
Lauren E Grosberg, Karthik Ganesan, Georges A Goetz, Sasidhar S Madugula, Nandita Bhaskhar, Victoria Fan, Peter Li, Pawel Hottowy, Wladyslaw Dabrowski, Alexander Sher, Alan M Litke, Subhasish Mitra, E J Chichilnisky
Epiretinal prostheses for treating blindness activate axon bundles, causing large, arc-shaped visual percepts that limit the quality of artificial vision. Improving the function of epiretinal prostheses therefore requires understanding and avoiding axon bundle activation. This paper introduces a method to detect axon bundle activation based on its electrical signature, and uses the method to test whether epiretinal stimulation can directly elicit spikes in individual retinal ganglion cells without activating nearby axon bundles...
May 31, 2017: Journal of Neurophysiology
https://www.readbyqxmd.com/read/28548648/electronic-retinal-implants-and-artificial-vision-journey-and-present
#5
REVIEW
J O Mills, A Jalil, P E Stanga
Retinitis pigmentosa and age-related macular degeneration are two significant causes of severe visual dysfunction. In both, the retinal photoreceptors degenerate, preventing successful conversion of light into electrical energy that is interpreted in the visual cortex as visual function. Artificial vision or visual function began over two centuries ago with the idea of creating artificial light pulses, or phosphenes, through cortical stimulation. The pursuit is now on to improve artificial visual function. Two retinal implants appear the most likely to succeed in the future having undergone multicentre human trials: the Argus II electronic epiretinal device (Second Sight Medical Products, CA, USA) and Alpha-IMS electronic subretinal device (Retina Implant AG, Germany)...
May 26, 2017: Eye
https://www.readbyqxmd.com/read/28541930/progress-in-artificial-vision-through-suprachoroidal-retinal-implants
#6
Lilach Bareket, Alejandro Barriga-Rivera, Marc Patrick Zapf, Nigel H Lovell, Gregg J Suaning
Retinal implants have proven their ability to restore visual sensation to people with degenerative retinopathy, characterized by photoreceptor cell death and the retina's inability to sense light. Retinal bionics operate by electrically stimulating the surviving neurons in the retina, thus triggering the transfer of visual sensory information to the brain. Suprachoroidal implants were first investigated in Australia in the 1950s. In this approach, the neuromodulation hardware is positioned between the sclera and the choroid, thus providing significant surgical and safety benefits for patients, with the potential to maintain residual vision combined with the artificial input from the device...
May 25, 2017: Journal of Neural Engineering
https://www.readbyqxmd.com/read/28532361/electrical-stimulation-of-the-retina-to-produce-artificial-vision
#7
James D Weiland, Steven T Walston, Mark S Humayun
Retinal prostheses aim to restore vision to blind individuals suffering from retinal diseases such as retinitis pigmentosa and age-related macular degeneration. These devices function by electrically stimulating surviving retinal neurons, whose activation is interpreted by the brain as a visual percept. Many prostheses are currently under development. They are categorized as epiretinal, subretinal, and suprachoroidal prostheses on the basis of the placement of the stimulating microelectrode array. Each can activate ganglion cells through direct or indirect stimulation...
October 14, 2016: Annual Review of Vision Science
https://www.readbyqxmd.com/read/28513500/rescue-vitrectomy-with-blocked-artery-massage-and-bloodletting-for-branch-retinal-artery-occlusion
#8
Chun-Ju Lin, Cheng-Wen Su, Huan-Sheng Chen, Wen-Lu Chen, Jane-Ming Lin, Yi-Yu Tsai
A 61-year-old male suffered from sudden blurred vision and superior visual field defect oculus dexter. His vision was counting fingers at 20 cm. Fundoscopy demonstrated inferior pale retina and a large embolus located at the proximal inferior retinal artery. Branch retinal artery occlusion (BRAO) was diagnosed. Initial paracentesis, topical brimonidine tartrate, oral pentoxifylline, and hyperbaric oxygen therapy were performed but showed limited improvement. Hence, he received 25-gauge vitrectomy, artificial posterior vitreous detachment, blocked retinal artery massage, and bloodletting 5 days after onset...
April 2017: Indian Journal of Ophthalmology
https://www.readbyqxmd.com/read/28449714/detecting-central-fixation-by-means-of-artificial-neural-networks-in-a-pediatric-vision-screener-using-retinal-birefringence-scanning
#9
Boris I Gramatikov
BACKGROUND: Reliable detection of central fixation and eye alignment is essential in the diagnosis of amblyopia ("lazy eye"), which can lead to blindness. Our lab has developed and reported earlier a pediatric vision screener that performs scanning of the retina around the fovea and analyzes changes in the polarization state of light as the scan progresses. Depending on the direction of gaze and the instrument design, the screener produces several signal frequencies that can be utilized in the detection of central fixation...
April 27, 2017: Biomedical Engineering Online
https://www.readbyqxmd.com/read/28422669/bioinspired-approach-to-modeling-retinal-ganglion-cells-using-system-identification-techniques
#10
Philip J Vance, Gautham P Das, Dermot Kerr, Sonya A Coleman, T Martin McGinnity, Tim Gollisch, Jian K Liu
The processing capabilities of biological vision systems are still vastly superior to artificial vision, even though this has been an active area of research for over half a century. Current artificial vision techniques integrate many insights from biology yet they remain far-off the capabilities of animals and humans in terms of speed, power, and performance. A key aspect to modeling the human visual system is the ability to accurately model the behavior and computation within the retina. In particular, we focus on modeling the retinal ganglion cells (RGCs) as they convey the accumulated data of real world images as action potentials onto the visual cortex via the optic nerve...
April 12, 2017: IEEE Transactions on Neural Networks and Learning Systems
https://www.readbyqxmd.com/read/28374068/light-at-night-acutely-impairs-glucose-tolerance-in-a-time-intensity-and-wavelength-dependent-manner-in-rats
#11
Anne-Loes Opperhuizen, Dirk J Stenvers, Remi D Jansen, Ewout Foppen, Eric Fliers, Andries Kalsbeek
AIMS/HYPOTHESIS: Exposure to light at night (LAN) has increased dramatically in recent decades. Animal studies have shown that chronic dim LAN induced obesity and glucose intolerance. Furthermore, several studies in humans have demonstrated that chronic exposure to artificial LAN may have adverse health effects with an increased risk of metabolic disorders, including type 2 diabetes. It is well-known that acute exposure to LAN affects biological clock function, hormone secretion and the activity of the autonomic nervous system, but data on the effects of LAN on glucose homeostasis are lacking...
July 2017: Diabetologia
https://www.readbyqxmd.com/read/28320674/simulation-study-of-an-ultrasound-retinal-prosthesis-with-a-novel-contact-lens-array-for-noninvasive-retinal-stimulation
#12
Mengdi Gao, Yanyan Yu, Huixia Zhao, Guofeng Li, Hongyang Jiang, Congzhi Wang, Feiyan Cai, Leanne Chan, Bernard Chiu, Wei Qian, Weibao Qiu, Hairong Zheng
Millions of people around the world suffer from varying degrees of vision loss (including complete blindness) because of retinal degenerative diseases. Artificial retinal prosthesis, which is usually based on electrical neurostimulation, are the most advanced technology for different types of retinal degeneration. However, this technology involves placing a device into the eyeball, and such a highly invasive procedure is inevitably highly risk and expensive. Ultrasound has been demonstrated to be a promising technology for noninvasive neurostimulation, making it possible to stimulate the retina and induce action potentials similar to those elicited by light stimulation...
March 15, 2017: IEEE Transactions on Neural Systems and Rehabilitation Engineering
https://www.readbyqxmd.com/read/28248989/efficacy-of-two-different-thiol-modified-crosslinked-hyaluronate-formulations-as-vitreous-replacement-compared-to-silicone-oil-in-a-model-of-retinal-detachment
#13
Sven Schnichels, Nele Schneider, Christine Hohenadl, José Hurst, Andreas Schatz, Kai Januschowski, Martin S Spitzer
The efficacy of two novel artificial vitreous body substitutes (VBS) consisting of highly biocompatible thiolated cross-linked hyaluronic acid (HA)-based hydrogels in comparison to silicone oil in a model of retinal detachment was investigated. Pars plana vitrectomy (23G) was performed in the right eye of 24 pigmented rabbits. Retinal detachment of two quadrants was induced by creating a small retinotomy near the vascular arcade and injecting balanced salt solution (BSS) subretinally. The retina was reattached by injecting air, which was followed by increasing the infusion pressure, and the retinal tear was treated by endolaser photocoagulation...
2017: PloS One
https://www.readbyqxmd.com/read/28198154/daily-and-seasonal-expression-profile-of-serum-melatonin-and-its-biosynthesizing-enzyme-genes-tph1-aanat1-aanat2-and-hiomt-in-pineal-organ-and-retina-a-study-under-natural-environmental-conditions-in-a-tropical-carp-catla-catla
#14
Chongtham Rajiv, Haobijam Sanjita Devi, Gopinath Mondal, Sijagurumayum Dharmajyoti Devi, Zeeshan Ahmad Khan, Thangal Yumnamcha, Rupjyoti Bharali, Asamanja Chattoraj
The tropical carp Catla catla is gaining importance for the studies of the impact of environmental changes on aquatic animals due to its surface dwelling habitat. To date, no information is available on the transcriptional profile of melatonin biosynthesizing enzyme genes in any tropical carp under either natural or artificial photothermal conditions in pineal and retina. The present study is an attempt to demonstrate the temporal pattern of expression of melatonin biosynthesizing enzyme genes, tryptophan hydroxylase 1 (tph1), arylalkylamine N-acetyltransferase (aanat1 and aanat2), and hydroxyindole-O-methyltransferase (hiomt) collectively and simultaneously in pineal organ and retina in tropical fish, C...
December 2016: Journal of Experimental Zoology. Part A, Ecological Genetics and Physiology
https://www.readbyqxmd.com/read/28179882/connecting-artificial-brains-to-robots-in-a-comprehensive-simulation-framework-the-neurorobotics-platform
#15
Egidio Falotico, Lorenzo Vannucci, Alessandro Ambrosano, Ugo Albanese, Stefan Ulbrich, Juan Camilo Vasquez Tieck, Georg Hinkel, Jacques Kaiser, Igor Peric, Oliver Denninger, Nino Cauli, Murat Kirtay, Arne Roennau, Gudrun Klinker, Axel Von Arnim, Luc Guyot, Daniel Peppicelli, Pablo Martínez-Cañada, Eduardo Ros, Patrick Maier, Sandro Weber, Manuel Huber, David Plecher, Florian Röhrbein, Stefan Deser, Alina Roitberg, Patrick van der Smagt, Rüdiger Dillman, Paul Levi, Cecilia Laschi, Alois C Knoll, Marc-Oliver Gewaltig
Combined efforts in the fields of neuroscience, computer science, and biology allowed to design biologically realistic models of the brain based on spiking neural networks. For a proper validation of these models, an embodiment in a dynamic and rich sensory environment, where the model is exposed to a realistic sensory-motor task, is needed. Due to the complexity of these brain models that, at the current stage, cannot deal with real-time constraints, it is not possible to embed them into a real-world task...
2017: Frontiers in Neurorobotics
https://www.readbyqxmd.com/read/28114567/retinotopic-to-spatiotopic-mapping-in-blind-patients-implanted-with-the-argus-ii-retinal-prosthesis
#16
Avi Caspi, Arup Roy, Jessy D Dorn, Robert J Greenberg
Purpose: To quantify the precision of mapping from retinotopic (retina-centered) to spatiotopic (world-centered) coordinates in blind humans implanted with a retinal prosthesis device. Additionally, to demonstrate that an eye tracker can be calibrated on sightless patients based on the percept from a visual implant. Methods: We directly activated epiretinal electrodes to create retinotopic stimuli and recorded the location of the percept at world-based coordinates...
January 1, 2017: Investigative Ophthalmology & Visual Science
https://www.readbyqxmd.com/read/28107513/the-zebrafish-anillin-egfp-reporter-marks-late-dividing-retinal-precursors-and-stem-cells-entering-neuronal-lineages
#17
Meret Cepero Malo, Anne-Laure Duchemin, Luca Guglielmi, Eva Patzel, Saadettin Sel, Gerd U Auffarth, Matthias Carl, Lucia Poggi
Monitoring cycling behaviours of stem and somatic cells in the living animal is a powerful tool to better understand tissue development and homeostasis. The tg(anillin:anillin-eGFP) transgenic line carries the full-length zebrafish F-actin binding protein Anillin fused to eGFP from a bacterial artificial chromosome (BAC) containing Anillin cis-regulatory sequences. Here we report the suitability of the Anillin-eGFP reporter as a direct indicator of cycling cells in the late embryonic and post-embryonic retina...
2017: PloS One
https://www.readbyqxmd.com/read/28060395/design-and-validation-of-a-training-simulator-for-laser-capsulotomy-peripheral-iridotomy-and-retinopexy
#18
Sarah M Simpson, Kelly D Schweitzer, Davin E Johnson
BACKGROUND AND OBJECTIVES: Ophthalmology trainees commonly learn laser procedures on live patients. A simulator for learning peripheral iridotomy (PI), posterior capsulotomy, and retinopexy may improve patient outcomes. MATERIALS AND METHODS: A model eye with artificial tissues was designed. The tissues reacted to laser similarly to human tissues. Inexperienced (n = 6; first- to third-year residents) and experienced (n = 7; fourth- to fifth-year residents and staff) ophthalmic personal were compared on performance of the above laser procedures...
January 1, 2017: Ophthalmic Surgery, Lasers & Imaging Retina
https://www.readbyqxmd.com/read/27958724/engineering-an-artificial-flavoprotein-magnetosensor
#19
Chris Bialas, Lauren E Jarocha, Kevin B Henbest, Tilo M Zollitsch, Goutham Kodali, Christiane R Timmel, Stuart R Mackenzie, P Leslie Dutton, Christopher C Moser, P J Hore
Migratory birds use the Earth's magnetic field as a source of navigational information. This light-dependent magnetic compass is thought to be mediated by cryptochrome proteins in the retina. Upon light activation, electron transfer between the flavin adenine dinucleotide cofactor and tryptophan residues leads to the formation of a spin-correlated radical pair, whose subsequent fate is sensitive to external magnetic fields. To learn more about the functional requirements of this complex chemical compass, we have created a family of simplified, adaptable proteins-maquettes-that contain a single tryptophan residue at different distances from a covalently bound flavin...
December 28, 2016: Journal of the American Chemical Society
https://www.readbyqxmd.com/read/27942525/are-long-stimulus-pulse-durations-the-answer-to-improving-spatial-resolution-in-retinal-prostheses
#20
COMMENT
Matthew A Petoe, Mohit N Shivdasani
Retinal prostheses can provide artificial vision to patients with degenerate retinae by electrically stimulating the remaining inner retinal neurons. The evoked perception is generally adequate for light localization, but of limited spatial resolution owing to the indiscriminate activation of multiple retinal cell types, leading to distortions in the perceived image. Here we present a perspective on a recent work by Weitz and colleagues who demonstrate a focal confinement of retinal ganglion cell (RGC) activation when using extended pulse durations in the stimulation waveform...
November 2016: Annals of Translational Medicine
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