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https://www.readbyqxmd.com/read/28549093/autoantibodies-in-melanoma-associated-retinopathy-recognize-an-epitope-conserved-between-trpm1-and-trpm3
#1
Robert M Duvoisin, Tammie L Haley, Gaoying Ren, Iwona Strycharska-Orczyk, James P Bonaparte, Catherine W Morgans
Purpose: Melanoma-associated retinopathy (MAR) is a paraneoplastic syndrome associated with malignant melanoma and the presence of anti-retinal autoantibodies, including autoantibodies against transient receptor potential melanopsin 1 (TRPM1), a cation channel expressed by both melanocytes and retinal bipolar cells. The goal of this study was to further map the antigenic epitope. Methods: Patient sera were tested by immunofluorescence and Western blotting on HEK293 cells transfected with enhanced green fluorescent protein (EGFP)-TRPM1 fusion constructs and mouse retina sections...
May 1, 2017: Investigative Ophthalmology & Visual Science
https://www.readbyqxmd.com/read/28545362/insight-into-the-role-of-photoreception-and-light-intervention-for-sleep-and-neuropsychiatric-behaviour-in-the-elderly
#2
Katharina Wulff, Russell G Foster
Light exerts influences on many physiological and behavioural functions in humans. These functions can be described as image-forming (IF) and non-image forming (NIF) visual processes, both originating in the retina of the eye. Image-forming refers to vision; the process of detecting and distinguishing shapes and colour of objects. Non-image forming refers to detecting level of light intensity or brightness of ambient space, which affects basal physiology such as cycles of rest and activity or the endocrine system...
May 22, 2017: Current Alzheimer Research
https://www.readbyqxmd.com/read/28545361/applying-melanopic-lux-to-measure-biological-light-effects-on-melatonin-suppression-and-subjective-sleepiness
#3
Claudia Nowozin, Amely Wahnschaffe, Andrea Rodenbeck, Jan de Zeeuw, Sven Hädel, Ruslan Kozakov, Heinz Schöpp, Mirjam Münch, Dieter Kunz
In the beginning of this century a novel photopigment, melanopsin, was discovered in a sub-class of retinal ganglion cells and its action spectrum was described. Shortly after, it became clear that melanopsin is one major contributor to non-visual eye-mediated effects of light on e.g. the circadian, neuroendocrine and neurobehavioral systems. First applied studies pointed out that these non-visual effects of light are relevant for wellbeing, performance and general health. A standardized measurement quantity for these non-visual effects does not exist, but would ease application...
May 22, 2017: Current Alzheimer Research
https://www.readbyqxmd.com/read/28535270/intrinsically-photosensitive-retinal-ganglion-cell-function-sleep-efficiency-and-depression-in-advanced-age-related-macular-degeneration
#4
Michelle L Maynard, Andrew J Zele, Anthony S Kwan, Beatrix Feigl
Purpose: Melanopsin expressing intrinsically photosensitive retinal ganglion cells (ipRGC) input to multiple brain regions including those for pupil control, circadian rhythms, sleep and mood regulation. Here we measured ipRGC function and its relationship to sleep quality and depression in patients with advanced AMD. Methods: The melanopsin-mediated post-illumination pupil response (PIPR) was measured in 53 patients with advanced AMD (age 78.8 ± 8.8 years) and in 20 healthy controls (age 72...
February 1, 2017: Investigative Ophthalmology & Visual Science
https://www.readbyqxmd.com/read/28532353/ocular-photoreception-for-circadian-rhythm-entrainment-in-mammals
#5
Russell N Van Gelder, Ethan D Buhr
Circadian rhythms are self-sustained, approximately 24-h rhythms of physiology and behavior. These rhythms are entrained to an exactly 24-h period by the daily light-dark cycle. Remarkably, mice lacking all rod and cone photoreceptors still demonstrate photic entrainment, an effect mediated by intrinsically photosensitive retinal ganglion cells (ipRGCs). These cells utilize melanopsin (OPN4) as their photopigment. Distinct from the ciliary rod and cone opsins, melanopsin appears to function as a stable photopigment utilizing sequential photon absorption for its photocycle; this photocycle, in turn, confers properties on ipRGCs such as sustained signaling and resistance from photic bleaching critical for an irradiance detection system...
October 14, 2016: Annual Review of Vision Science
https://www.readbyqxmd.com/read/28528909/melanopsin-contributions-to-the-representation-of-images-in-the-early-visual-system
#6
Annette E Allen, Riccardo Storchi, Franck P Martial, Robert A Bedford, Robert J Lucas
Melanopsin photoreception enhances retinal responses to variations in ambient light (irradiance) and drives non-image-forming visual reflexes such as circadian entrainment [1-6]. Melanopsin signals also reach brain regions responsible for form vision [7-9], but melanopsin's contribution, if any, to encoding visual images remains unclear. We addressed this deficit using principles of receptor silent substitution to present images in which visibility for melanopsin versus rods+cones was independently modulated, and we recorded evoked responses in the mouse dorsal lateral geniculate nucleus (dLGN; thalamic relay for cortical vision)...
May 17, 2017: Current Biology: CB
https://www.readbyqxmd.com/read/28525301/mood-the-circadian-system-and-melanopsin-retinal-ganglion-cells
#7
Lorenzo Lazzerini Ospri, Glen Prusky, Samer Hattar
The discovery of a third type of photoreceptors in the mammalian retina, intrinsically photosensitive retinal ganglion cells (ipRGCs), has had a revolutionary impact on chronobiology. We can now properly account for numerous nonvision-related functions of light, including its effect on the circadian system. Here, we give an overview of ipRGCs and their function as it relates specifically to mood and biological rhythms. Although circadian disruptions have been traditionally hypothesized to be the mediators of light's effects on mood, here we present an alternative model that dispenses with assumptions of causality between the two phenomena and explains mood regulation by light via another ipRGC-dependent mechanism...
May 17, 2017: Annual Review of Neuroscience
https://www.readbyqxmd.com/read/28522986/retinal-ganglion-cells-and-circadian-rhythms-in-alzheimer-s-disease-parkinson-s-disease-and-beyond
#8
REVIEW
Chiara La Morgia, Fred N Ross-Cisneros, Alfredo A Sadun, Valerio Carelli
There is increasing awareness on the role played by circadian rhythm abnormalities in neurodegenerative disorders such as Alzheimer's disease (AD) and Parkinson's disease (PD). The characterization of the circadian dysfunction parallels the mounting evidence that the hallmarks of neurodegeneration also affect the retina and frequently lead to loss of retinal ganglion cells (RGCs) and to different degrees of optic neuropathy. In the RGC population, there is the subgroup of cells intrinsically photosensitive and expressing the photopigment melanopsin [melanopsin-containing retinal ganglion cells (mRGCs)], which are now well known to drive the entrainment of circadian rhythms to the light-dark cycles...
2017: Frontiers in Neurology
https://www.readbyqxmd.com/read/28491019/shared-and-differential-retinal-responses-against-optic-nerve-injury-and-ocular-hypertension
#9
REVIEW
Manuel Vidal-Sanz, Caridad Galindo-Romero, Francisco J Valiente-Soriano, Francisco M Nadal-Nicolás, Arturo Ortin-Martinez, Giuseppe Rovere, Manuel Salinas-Navarro, Fernando Lucas-Ruiz, Maria C Sanchez-Migallon, Paloma Sobrado-Calvo, Marcelino Aviles-Trigueros, María P Villegas-Pérez, Marta Agudo-Barriuso
Glaucoma, one of the leading causes of blindness worldwide, affects primarily retinal ganglion cells (RGCs) and their axons. The pathophysiology of glaucoma is not fully understood, but it is currently believed that damage to RGC axons at the optic nerve head plays a major role. Rodent models to study glaucoma include those that mimic either ocular hypertension or optic nerve injury. Here we review the anatomical loss of the general population of RGCs (that express Brn3a; Brn3a(+)RGCs) and of the intrinsically photosensitive RGCs (that express melanopsin; m(+)RGCs) after chronic (LP-OHT) or acute (A-OHT) ocular hypertension and after complete intraorbital optic nerve transection (ONT) or crush (ONC)...
2017: Frontiers in Neuroscience
https://www.readbyqxmd.com/read/28420980/loss-of-melanopsin-expressing-ganglion-cell-subtypes-and-dendritic-degeneration-in-the-aging-human-retina
#10
Gema Esquiva, Pedro Lax, Juan J Pérez-Santonja, José M García-Fernández, Nicolás Cuenca
In mammals, melanopsin-expressing retinal ganglion cells (mRGCs) are, among other things, involved in several non-image-forming visual functions, including light entrainment of circadian rhythms. Considering the profound impact of aging on visual function and ophthalmic diseases, here we evaluate changes in mRGCs throughout the life span in humans. In 24 post-mortem retinas from anonymous human donors aged 10-81 years, we assessed the distribution, number and morphology of mRGCs by immunostaining vertical retinal sections and whole-mount retinas with antibodies against melanopsin...
2017: Frontiers in Aging Neuroscience
https://www.readbyqxmd.com/read/28414048/light-and-the-laboratory-mouse
#11
Stuart N Peirson, Laurence A Brown, Carina A Pothecary, Lindsay A Benson, Angus S Fisk
Light exerts widespread effects on physiology and behaviour. As well as the widely-appreciated role of light in vision, light also plays a critical role in many non-visual responses, including regulating circadian rhythms, sleep, pupil constriction, heart rate, hormone release and learning and memory. In mammals, responses to light are all mediated via retinal photoreceptors, including the classical rods and cones involved in vision as well as the recently identified melanopsin-expressing photoreceptive retinal ganglion cells (pRGCs)...
April 13, 2017: Journal of Neuroscience Methods
https://www.readbyqxmd.com/read/28412540/melanopsin-expressing-retinal-ganglion-cells-are-resistant-to-cell-injury-but-not-always
#12
Birgitte Georg, Anna Ghelli, Carla Giordano, Fred N Ross-Cisneros, Alfredo A Sadun, Valerio Carelli, Jens Hannibal, Chiara La Morgia
Melanopsin retinal ganglion cells (mRGCs) are intrinsically photosensitive RGCs deputed to non-image forming functions of the eye such as synchronization of circadian rhythms to light-dark cycle. These cells are characterized by unique electrophysiological, anatomical and biochemical properties and are usually more resistant than conventional RGCs to different insults, such as axotomy and different paradigms of stress. We also demonstrated that these cells are relatively spared compared to conventional RGCs in mitochondrial optic neuropathies (Leber's hereditary optic neuropathy and Dominant Optic Atrophy)...
April 12, 2017: Mitochondrion
https://www.readbyqxmd.com/read/28399269/loss-of-melanopsin-expressing-retinal-ganglion-cells-in-patients-with-diabetic-retinopathy
#13
Elisabeth Anne Obara, Jens Hannibal, Steffen Heegaard, Jan Fahrenkrug
Purpose: Photo-entrainment of the circadian clock is mediated by melanopsin-expressing retinal ganglion cells (mRGCs) located in the retina. Patients suffering from diabetic retinopathy (DR) show impairment of light regulated circadian activity such as sleep disorders, altered blood pressure, and abnormal melatonin secretion. The aim of this study was to assess the impact of DR on the expression of mRGCs in the human retina. Methods: The expression of mRGCs and RGCs was determined in eye sections containing retinal tissue from patients with DR (n = 6) and respective age-matched controls (n = 8) using immunohistochemistry by costaining with antibodies against RNA binding protein with multiple splicing (RBPMS), which identified RGCs and melanopsin which identified the mRGCs...
April 1, 2017: Investigative Ophthalmology & Visual Science
https://www.readbyqxmd.com/read/28395083/pathological-confirmation-of-optic-neuropathy-in-familial-dysautonomia
#14
Carlos E Mendoza-Santiesteban, Jose-Alberto Palma, Thomas R Hedges, Nora V Laver, Nada Farhat, Lucy Norcliffe-Kaufmann, Horacio Kaufmann
Clinical data suggest that optic neuropathy and retinal ganglion cell loss are the main cause of visual decline in patients with familial dysautonomia, but this has not previously been confirmed by pathological analyses. We studied retinas and optic nerves in 6 eyes from 3 affected patients obtained at autopsy. Analyses included routine neurohistology and immunohistochemistry for neurofilaments, cytochrome c oxidase (COX), and melanopsin-containing ganglion cells. We observed profound axon loss in the temporal portions of optic nerves with relative preservation in the nasal portions; this correlated with clinical and optical coherence tomography findings in 1 patient...
March 1, 2017: Journal of Neuropathology and Experimental Neurology
https://www.readbyqxmd.com/read/28339754/expression-of-deep-brain-photoreceptors-in-the-pekin-drake-a-possible-role-in-the-maintenance-of-testicular-function
#15
R Haas, E Alenciks, S Meddle, G S Fraley
Several putative deep brain photoreceptors (DBPs) have been identified, such as melanopsin, opsin 5, and vertebrate ancient opsin. The aim of this study was to elucidate the role of DBPs in gonadal regulation in the Pekin drake. As previously reported, we observed opsin-like immunoreactivity (-ir) in the lateral septum (LS), melanopsin-ir in the premammillary nucleus (PMM), and opsin 5-ir in the periventricular organ. To determine the sensitivity of the DBPs to specific wavelengths of light, drakes were given an acute exposure to red, blue, or white light...
February 23, 2017: Poultry Science
https://www.readbyqxmd.com/read/28332564/pupillary-responses-in-non-proliferative-diabetic-retinopathy
#16
Jason C Park, Yi-Fan Chen, Norman P Blair, Felix Y Chau, Jennifer I Lim, Yannek I Leiderman, Mahnaz Shahidi, J Jason McAnany
The goal of this study was to determine the extent of rod-, cone-, and melanopsin-mediated pupillary light reflex (PLR) abnormalities in diabetic patients who have non-proliferative diabetic retinopathy (NPDR). Fifty diabetic subjects who have different stages of NPDR and 25 age-equivalent, non-diabetic controls participated. PLRs were measured in response to full-field, brief-flash stimuli under conditions that target the rod, cone, and intrinsically-photosensitive (melanopsin) retinal ganglion cell pathways...
March 23, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28271634/choroideremia-melanopsin-mediated-postillumination-pupil-relaxation-is-abnormally-slow
#17
Shakoor Ba-Ali, Søren Kirchhoff Christensen, Birgit Sander, Thomas Rosenberg, Michael Larsen, Henrik Lund-Andersen
PURPOSE: To investigate the rod-cone and melanopsin pupillary light response (PLR) pathways in choroideremia. METHODS: Eight patients with choroideremia and 18 healthy age-matched controls underwent chromatic pupillometry by applying blue (463 nm) and red light (643 nm) at 100 lux intensity to the right eye while recording pupil diameters. Absolute baseline pupil size (mm), normalized maximal pupil constriction and the early and late postillumination pupillary dilation, from 0 to 10 seconds and 10 to 30 seconds after the end of illumination, respectively, were determined...
March 8, 2017: Acta Ophthalmologica
https://www.readbyqxmd.com/read/28266650/pupillary-responses-to-short-wavelength-light-are-preserved-in-aging
#18
A V Rukmini, Dan Milea, Tin Aung, Joshua J Gooley
With aging, less blue light reaches the retina due to gradual yellowing of the lens. This could result in reduced activation of blue light-sensitive melanopsin-containing retinal ganglion cells, which mediate non-visual light responses (e.g., the pupillary light reflex, melatonin suppression, and circadian resetting). Herein, we tested the hypothesis that older individuals show greater impairment of pupillary responses to blue light relative to red light. Dose-response curves for pupillary constriction to 469-nm blue light and 631-nm red light were compared between young normal adults aged 21-30 years (n = 60) and older adults aged ≥50 years (normal, n = 54; mild cataract, n = 107; severe cataract, n = 18)...
March 7, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28264100/the-relation-between-light-induced-lacrimation-and-the-melanopsin-driven-postillumination-pupil-response
#19
Shaobo Lei, Herbert C Goltz, Xingqiao Chen, Marija Zivcevska, Agnes M F Wong
Purpose: To investigate the chromatic characteristics and intensity-response function of light-induced reflex lacrimation and its correlation with the melanopsin-driven postillumination pupil response (PIPR). Methods: Eleven visually normal participants completed the experiment. Lacrimation was measured in one eye by placing a calibrated filter paper strip in the conjunctival sac over a 1 minute-interval (Schirmer's test) during which participants received either no light stimulation (baseline trial) or one flash of blue or red light stimuli presented binocularly with a Ganzfeld stimulator, while the pupil response was recorded simultaneously from the fellow eye by using an eye tracker...
March 1, 2017: Investigative Ophthalmology & Visual Science
https://www.readbyqxmd.com/read/28251921/clinical-implications-of-the-melanopsin-based-non-image-forming-visual-system
#20
REVIEW
Alexander Ksendzovsky, I Jonathan Pomeraniec, Kareem A Zaghloul, J Javier Provencio, Ignacio Provencio
Since the discovery of the non-image-forming visual system, tremendous research efforts have been dedicated to understanding its mechanisms and functional roles. Original functions associated with the melanopsin system include the photoentrainment of circadian sleep-wake cycles and the pupillary light reflex. Recent findings, however, suggest a much broader involvement of this system in an array of physiologic responses to light. This newfound insight into the underlying function of the non-image-forming system has revealed the many connections to human pathology and attendant disease states, including seasonal affective disorder, migraine, glaucoma, inherited mitochondrial optic neuropathy, and sleep dysregulation of aging...
March 28, 2017: Neurology
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