keyword
https://read.qxmd.com/read/38443311/natural-history-and-biomarkers-of-kcnv2-associated-retinopathy
#1
JOURNAL ARTICLE
Dhimas H Sakti, Elisa E Cornish, Haipha Ali, Stephanie Retsas, Marium Raza, Nonna Saakova, Livia S Carvalho, Benjamin M Nash, Robyn V Jamieson, John R Grigg
BACKGROUND: KCNV2-associated retinopathy is an autosomal recessive inherited retinal disease classically named cone dystrophy with supernormal rod response (CDSRR). This study aims to identify the best biomarker for evaluating the condition. METHODS: A retrospective review of eight patients from seven families with genetically confirmed KCNV2-associated retinopathy was performed. The best corrected visual acuity (BCVA), full-field electroretinogram (ffERG), pattern ERG (pERG), fundus imaging: retinal photograph and fundus autofluorescence (FAF), and optical coherence tomography (OCT) were analysed...
March 5, 2024: Clinical & Experimental Ophthalmology
https://read.qxmd.com/read/38333056/the-mongolian-gerbil-as-an-advanced-model-to-study-cone-system-physiology
#2
JOURNAL ARTICLE
Alexander Günter, Soumaya Belhadj, Mathias W Seeliger, Regine Mühlfriedel
In this work, we introduce a diurnal rodent, the Mongolian gerbil ( Meriones unguiculatus ) (MG) as an alternative to study retinal cone system physiology and pathophysiology in mice. The cone system is of particular importance, as it provides high-acuity and color vision and its impairment in retinal disorders is thus especially disabling. Despite their nocturnal lifestyle, mice are currently the most popular animals to study cone-related diseases due to the high availability of genetically modified models...
2024: Frontiers in Cellular Neuroscience
https://read.qxmd.com/read/38076962/modeling-aging-and-retinal-degeneration-with-mitochondrial-dna-mutation-burden
#3
John Sturgis, Rupesh Singh, Quinn Caron, Ivy S Samuels, Thomas Micheal Shiju, Aditi Mukkara, Paul Freedman, Vera L Bonilha
Somatic mitochondrial DNA (mtDNA) mutation accumulation has been observed in individuals with retinal degenerative disorders. To study the effects of aging and mtDNA mutation accumulation in the retina, a Polymerase gamma (POLG) deficiency model, the POLG D257A mutator mice (PolgD257A), was used. POLG is an enzyme responsible for regulating mtDNA replication and repair. Retinas of young and older mice with this mutation were analyzed in vivo and ex vivo to provide new insights into the contribution of age-related mitochondrial dysfunction due to mtDNA damage...
December 1, 2023: bioRxiv
https://read.qxmd.com/read/37999773/association-between-choroidopathy-and-photoreceptors-during-the-early-stage-of-diabetic-retinopathy-a-cross-sectional-study
#4
JOURNAL ARTICLE
Ningxin Dou, Guangyang Li, Dong Fang, Shaochong Zhang, Xiaoling Liang, Shanshan Yu
PURPOSE: To explore the role of choroidopathy in diabetic retinopathy (DR) by investigating the correlation between alterations of choroidal vessel and photoreceptors during the early stage of DR. METHODS: We performed a cross-sectional comparison of diabetic patients without DR (NDR group; n=16) and those with mild nonproliferative diabetic retinopathy (NPDR group; n=39). Optical coherence tomography (OCT) images of choroidal vessel alterations and photoreceptor structures were evaluated using the choroidal vascularity index (CVI) and adjusted ellipsoid zone (EZ) reflectivity, respectively...
November 24, 2023: Graefe's Archive for Clinical and Experimental Ophthalmology
https://read.qxmd.com/read/37924416/cone-driven-strong-flash-electroretinograms-in-healthy-adults-prevalence-of-negative-waveforms
#5
JOURNAL ARTICLE
Xiaofan Jiang, Taha Bhatti, Ambreen Tariq, Shaun M Leo, Nancy Aychoua, Andrew R Webster, Pirro G Hysi, Christopher J Hammond, Omar A Mahroo
PURPOSE: Both rod and cone-driven signals contribute to the electroretinogram (ERG) elicited by a standard strong flash in the dark. Negative ERGs usually reflect inner retinal dysfunction. However, in diseases where rod photoreceptor function is selectively lost, a negative waveform might represent the response of the dark-adapted cone system. To investigate the dark-adapted cone-driven waveform in healthy individuals, we delivered flashes on a dim blue background, designed to saturate the rods, but minimally adapt the cones...
November 4, 2023: Documenta Ophthalmologica. Advances in Ophthalmology
https://read.qxmd.com/read/37835784/the-value-of-electroretinography-in-identifying-candidate-genes-for-inherited-retinal-dystrophies-a-diagnostic-guide
#6
REVIEW
Tsai-Hsuan Yang, Eugene Yu-Chuan Kang, Pei-Hsuan Lin, Pei-Liang Wu, Jacob Aaron Sachs, Nan-Kai Wang
Inherited retinal dystrophies (IRDs) are a group of heterogeneous diseases caused by genetic mutations that specifically affect the function of the rod, cone, or bipolar cells in the retina. Electroretinography (ERG) is a diagnostic tool that measures the electrical activity of the retina in response to light stimuli, and it can help to determine the function of these cells. A normal ERG response consists of two waves, the a-wave and the b-wave, which reflect the activity of the photoreceptor cells and the bipolar and Muller cells, respectively...
September 25, 2023: Diagnostics
https://read.qxmd.com/read/37797989/8%C3%A2-unexpected-retinopathy-in-a-patient-presenting-with-bilateral-optic-disc-swelling
#7
JOURNAL ARTICLE
G Kiray, V Panteli, N Enright, S Handley, O Marmoy, D Thompson, R Henderson
A 12-year-old boy presented with 5 day history of blurry vision, 'wobbly eyes', tinnitus and difficulty seeing at night. Local ophthalmology noted bilateral optic disc swelling and referred him urgently for neurological investigations.Clinical Findings: At presentation VA was RE 0.00 and LE 0.2 with normal Ishihara colour vision. His extraocular movements were full without manifest strabismus. Fundoscopy showed bilateral optic disc swelling. Electrophysiology unexpectedly revealed a functionally cone isolated retina with markedly abnormal rod function...
October 2023: BMJ Open Ophthalmology
https://read.qxmd.com/read/37583414/single-opsin-driven-white-noise-ergs-in-mice
#8
JOURNAL ARTICLE
Nina Stallwitz, Anneka Joachimsthaler, Jan Kremers
PURPOSE: Electroretinograms elicited by photopigment isolating white noise stimuli (wnERGs) in mice were measured. The dependency of rod- and cone-opsin-driven wnERGs on mean luminance was studied. METHODS: Temporal white noise stimuli (containing all frequencies up to 20 Hz, equal amplitudes, random phases) that modulated either rhodopsin, S-opsin or L*-opsin, using the double silent substitution technique, were used to record wnERGs in mice expressing a human L*-opsin instead of the native murine M-opsin...
2023: Frontiers in Neuroscience
https://read.qxmd.com/read/37465364/the-origins-of-the-full-field-flash-electroretinogram-b-wave
#9
REVIEW
Yashvi Bhatt, David M Hunt, Livia S Carvalho
The electroretinogram (ERG) measures the electrical activity of retinal neurons and glial cells in response to a light stimulus. Amongst other techniques, clinicians utilize the ERG to diagnose various eye diseases, including inherited conditions such as cone-rod dystrophy, rod-cone dystrophy, retinitis pigmentosa and Usher syndrome, and to assess overall retinal health. An ERG measures the scotopic and photopic systems separately and mainly consists of an a-wave and a b-wave. The other major components of the dark-adapted ERG response include the oscillatory potentials, c-wave, and d-wave...
2023: Frontiers in Molecular Neuroscience
https://read.qxmd.com/read/37440055/compensatory-cone-mediated-mechanisms-in-inherited-retinal-degeneration-mouse-models-a-functional-and-gene-expression-analysis
#10
JOURNAL ARTICLE
Alicia A Brunet, David M Hunt, Carla Mellough, Alan R Harvey, Livia S Carvalho
The retina undergoes compensatory changes in response to progressive photoreceptor loss/dysfunction; however, studies of inherited retinal diseases (IRDs) often lack a temporal connection between gene expression and visual function. Here, we used three mouse models of IRD - Cnga3-/- , Pde6ccpfl1 , and Rd1 - to investigate over time the effect of photoreceptor degeneration, particularly cones, on visual function and gene expression. Changes to gene expression include increases in cell survival and cell death genes in Pde6ccpfl1 before significant cell loss, as well as an increase in cone-specific genes in the Rd1 at the peak of rod death...
2023: Advances in Experimental Medicine and Biology
https://read.qxmd.com/read/37433860/cone-dystrophy-associated-with-autoimmune-polyglandular-syndrome-type-1
#11
JOURNAL ARTICLE
Abdulrahman Badawi, Moustafa Magliyah, Omar Alabbasi, Lama AlAbdi, Fowzan S Alkuraya, Patrik Schatz, Hani Basher ALBalawi, Marco Mura
To report the association of autoimmune polyglandular syndrome type 1 (APS1) with cone dystrophy in a large Saudi family. This is a Retrospective chart review and prospective genetic testing and ophthalmic examination of a large multiplex consanguineous family. Genetic testing was performed on 14 family members, seven of whom had detailed ophthalmic examinations. Medical history, ocular history and evaluation, visual field testing, full-field electroretinogram (ERG), and Whole Exome Sequencing (WES) results were analyzed...
July 11, 2023: Scientific Reports
https://read.qxmd.com/read/37425946/synaptotagmin-9-in-mouse-retina
#12
Chris S Mesnard, Cassandra L Hays, Cody L Barta, C B Gurumurthy, Wallace B Thoreson
Synaptotagmin-9 (Syt9) is a Ca 2+ sensor mediating fast synaptic release expressed in many parts of the brain. The presence and role of Syt9 in retina is unknown. We found evidence for Syt9 expression throughout the retina and created mice to conditionally eliminate Syt9 in a cre-dependent manner. We crossed Syt9 fl/fl mice with Rho-iCre, HRGP-Cre, and CMV-cre mice to generate mice in which Syt9 was eliminated from rods (rod Syt9CKO ), cones (cone Syt9CKO ), or whole animals (CMV Syt9 ). CMV Syt9 mice showed an increase in scotopic electroretinogram (ERG) b-waves evoked by bright flashes with no change in a-waves...
June 28, 2023: bioRxiv
https://read.qxmd.com/read/36555803/electroretinography-as-a-biomarker-to-monitor-the-progression-of-stargardt-disease
#13
JOURNAL ARTICLE
Jana Sajovic, Andrej Meglič, Marko Hawlina, Ana Fakin
The aim of the present study is to determine how electroretinographic (ERG) responses reflect age-related disease progression in the Stargardt disease (STGD1). The prospective comparative cohort study included 8 patients harboring two null ABCA4 variants (Group 1) and 34 patients with other ABCA4 genotypes (Group 2). Age at exam, age at onset, visual acuity (VA) and ERG responses were evaluated. The correlation between ERG responses and age in each patient group was determined using linear regression. A Mann-Whitney U Test was used to compare the median values between the groups...
December 18, 2022: International Journal of Molecular Sciences
https://read.qxmd.com/read/36351817/the-developmental-progression-of-eight-opsin-spectral-signals-recorded-from-the-zebrafish-retinal-cone-layer-is-altered-by-the-timing-and-cell-type-expression-of-thyroxin-receptor-%C3%AE-2-tr%C3%AE-2-gain-of-function-transgenes
#14
JOURNAL ARTICLE
Ralph F Nelson, Annika Balraj, Tara Suresh, Leah J Elias, Takeshi Yoshimatsu, Sara S Patterson
Zebrafish retinal cone signals shift in spectral shape through larval, juvenile, and adult development as expression patterns of eight cone-opsin genes change. An algorithm extracting signal amplitudes for the component cone spectral types is developed and tested on two thyroxin receptor β2 (trβ2) gain-of-function lines crx:mYFP-2A-trβ2 and gnat2:mYFP-2A-trβ2 , allowing correlation between opsin signaling and opsin immunoreactivity in lines with different developmental timing and cell-type expression of this red-opsin-promoting transgene...
November 9, 2022: ENeuro
https://read.qxmd.com/read/36338670/sulforaphane-recovers-cone-function-in-an-nrf2-dependent-manner-in-middle-aged-mice-undergoing-rpe-oxidative-stress
#15
JOURNAL ARTICLE
Xiaoping Qi, Dorothy A Walton, Kendra S Plafker, Michael E Boulton, Scott M Plafker
Purpose: Sulforaphane (SFN) is an isothiocyanate derived from cruciferous vegetables that has therapeutic efficacy in numerous animal models of human disease, including mouse models of retinal degeneration. However, despite dozens of clinical trials, the compound remains to be tested as a clinical treatment for ocular disease. Numerous cellular activities of SFN have been identified, including the activation of Nrf2, a transcription factor that induces a battery of target gene products to neutralize oxidative and xenobiotic stresses...
2022: Molecular Vision
https://read.qxmd.com/read/36280223/synaptotagmins-1-and-7-in-vesicle-release-from-rods-of-mouse-retina
#16
JOURNAL ARTICLE
C S Mesnard, C L Hays, C L Barta, A L Sladek, J J Grassmeyer, K K Hinz, R M Quadros, C B Gurumurthy, W B Thoreson
Synaptotagmins are the primary Ca2+ sensors for synaptic exocytosis. Previous work suggested synaptotagmin-1 (Syt1) mediates evoked vesicle release from cone photoreceptor cells in the vertebrate retina whereas release from rods may involve another sensor in addition to Syt1. We found immunohistochemical evidence for syntaptotagmin-7 (Syt7) in mouse rod terminals and so performed electroretinograms (ERG) and single-cell recordings using mice in which Syt1 and/or Syt7 were conditionally removed from rods and/or cones...
October 22, 2022: Experimental Eye Research
https://read.qxmd.com/read/36265576/fmr-protein-evidence-of-an-emerging-role-in-retinal-aging
#17
JOURNAL ARTICLE
M Ardourel, I Ranchon-Cole, A Pâris, C Felgerolle, N Acar, F Lesne, S Briault, O Perche
Aging is a multifactorial process that affects the entire organism by cumulative alterations. Visual function impairments that go along with aging are commonly observed, causing lower visual acuity, lower contrast sensitivity, and impaired dark adaptation. Electroretinogram analysis revealed that the amplitudes of rod- and cone-mediated responses are reduced in aged mice and humans. Reports suggested that age-related changes observed in both rod and cone photoreceptor functionality were linked to oxidative stress regulation or free radical production homeostasis...
October 17, 2022: Experimental Eye Research
https://read.qxmd.com/read/36173494/melanoma-associated-retinopathy-with-anti-trpm1-autoantibodies-showing-concomitant-off-bipolar-cell-dysfunction
#18
JOURNAL ARTICLE
Wei-Che Hung, Hui-Chen Cheng, An-Guor Wang
BACKGROUND: To report the clinical features of a patient with melanoma-associated retinopathy (MAR) with anti-transient receptor potential cation channel, subfamily M, member 1 (TRPM1) autoantibodies showing concomitant Off-bipolar cell dysfunction. METHODS: We evaluated a patient with a past history of scalp melanoma presented with sudden-onset shimmering photopsia in both eyes. MAR was confirmed with complete ophthalmic examinations, electronegative electroretinogram (ERG), and the presence of anti-TRPM1 autoantibodies by Western blot analysis...
September 29, 2022: Documenta Ophthalmologica. Advances in Ophthalmology
https://read.qxmd.com/read/36140584/a-novel-autosomal-recessive-variant-of-the-nrl-gene-causing-enhanced-s-cone-syndrome-a-morpho-functional-analysis-of-two-unrelated-pediatric-patients
#19
JOURNAL ARTICLE
Giancarlo Iarossi, Lorenzo Sinibaldi, Chiara Passarelli, Andrea Maria Coppe', Alessandro Cappelli, Gianni Petrocelli, Gino Catena, Chiara Perrone, Benedetto Falsini, Antonio Novelli, Andrea Bartuli, Luca Buzzonetti
Enhanced S-cone syndrome (ESCS) is a rare autosomal recessive retinal degeneration mainly associated with pathogenic variations in the NR2E3 gene. Only a few pathogenic variations in the NRL gene associated with ESCS have been reported to date. Here, we describe the clinical and genetic findings of two unrelated pediatric patients with a novel frameshift homozygous variant in the NRL gene. Fundus examinations showed signs of peripheral degeneration in both patients, more severe in Proband 2, with relative sparing of the macular area...
September 9, 2022: Diagnostics
https://read.qxmd.com/read/36078159/age-and-sex-related-changes-in-retinal-function-in-the-vervet-monkey
#20
JOURNAL ARTICLE
Catarina Micaelo-Fernandes, Joseph Bouskila, Roberta M Palmour, Jean-François Bouchard, Maurice Ptito
Among the deficits in visual processing that accompany healthy aging, the earliest originate in the retina. Moreover, sex-related differences in retinal function have been increasingly recognized. To better understand the dynamics of the retinal aging trajectory, we used the light-adapted flicker electroretinogram (ERG) to functionally assess the state of the neuroretina in a large cohort of age- and sex-matched vervet monkeys ( N = 35), aged 9 to 28 years old, with no signs of obvious ocular pathology. We primarily isolated the cone-bipolar axis by stimulating the retina with a standard intensity light flash (2...
September 3, 2022: Cells
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