Untitled

Narfström, Kristina; Ekesten, Björn; Rosolen, Serge G.; Spiess, Bernhard M.; Percicot, Christine L.; Ofri, Ron

doi:10.1023/a:1020524305726

Cited by 99 publications

(29 citation statements)

References 6 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…The right and left mini-ganzfeld domes were positioned approximately 2 cm from the corresponding eye. Each ERG session consisted of scotopic and photopic recordings in accordance with the Dog Diagnostic Protocol, recommended by the European College of Veterinary Ophthalmology, primarily for evaluation of rod and cone function (Narfström et al 2002). Throughout a 20 minute period of dark adaptation, scotopic low-intensity rod responses were elicited at a stimulus intensity of 10.2 log photons/cm 2 /s (0.01 cd/m 2 ) with 4 minutes of dark adaptation between recordings.…”

Section: Methodsmentioning

confidence: 99%

Pupillary light reflex deficits in a canine model of late infantile neuronal ceroid lipofuscinosis

Whiting¹,

Narfström²,

Yao³

et al. 2013

Experimental Eye Research

Self Cite

View full text Add to dashboard Cite

Late-infantile neuronal ceroid lipofuscinosis (CLN2) is a hereditary neurological disorder characterized by progressive retinal degeneration and vision loss, cognitive and motor decline, seizures, and pronounced brain atrophy. The progressive loss of neurological functions eventually leads to death, usually by the early teenage years. Utilizing a canine model of CLN2, therapeutic studies to inhibit the brain and retinal degenerations are currently under way. Using this dog model, studies were undertaken to compare quantitative assessments of the pupillary light reflex (PLR) and electroretinography (ERG) as tools for evaluating the effects of the disease on retinal function. The PLR and ERG were recorded in normal and CLN2-affected Dachshunds at 2 month intervals between the ages of 4 and 10 months. Using custom instrumentation for quantitative PLR assessments, a series of white light stimuli of varying intensity was used to elicit pupil constriction, and pupil images were recorded using continuous infrared illumination and an infrared-sensitive camera. Electroretinography was used to evaluate retinal function in the same dogs. As the disease progressed, affected dogs exhibited progressive and profound declines in ERG amplitudes under both scotopic and photopic conditions. With low intensity light stimuli, CLN2 was also accompanied by progressive deficits in the PLR. Changes in the PLR to dim light stimuli included significant deficits in latency, constriction velocity, constriction amplitude, and redilation velocity. However, despite the almost complete loss of detectable ERG responses by disease end stage, the PLR to bright stimuli was well preserved throughout the disease progression. These findings demonstrate that the PLR is much more sensitive than the ERG in detecting residual retinal function in animal models of retinal degenerative disease. The preservation of the PLR in dogs with profoundly depressed ERGs correlates with a preservation of visually-mediated behavior even late in the disease progression. Quantitative analysis of the PLR has potential as a biomarker in animal models of retinal degenerative diseases and in evaluating the efficacy of therapeutic interventions in preserving retinal function.

show abstract

Section: Methodsmentioning

confidence: 99%

Pupillary light reflex deficits in a canine model of late infantile neuronal ceroid lipofuscinosis

Whiting¹,

Narfström²,

Yao³

et al. 2013

Experimental Eye Research

Self Cite

View full text Add to dashboard Cite

show abstract

“…Each ERG session consisted of scotopic and photopic ERGs in accordance with the “Dog Diagnostic Protocol,” recommended by the European College of Veterinary Ophthalmologists, primarily for evaluation and separation of rod and cone function [30]. This protocol is preprogrammed on the ERG unit and is executed automatically upon initiation of the ERG session by the examiner.…”

Section: Methodsmentioning

confidence: 99%

“…Data were collected automatically on the compact flash card of the ERG unit, transferred to a computer, printed, and stored for further analysis. ERGs were evaluated and the amplitudes and implicit times for the a- and b-waves were measured as previously described [30]. …”

Section: Methodsmentioning

confidence: 99%

Assessment of Hereditary Retinal Degeneration in the English Springer Spaniel Dog and Disease Relationship to anRPGRIP1Mutation

Narfström

Jeong

Hyman

et al. 2012

Stem Cells International

Self Cite

View full text Add to dashboard Cite

Intensive breeding and selection on desired traits have produced high rates of inherited diseases in dogs. Hereditary retinal degeneration, often called progressive retinal atrophy (PRA), is prevalent in dogs with disease entities comparable to human retinitis pigmentosa (RP) and Leber's congenital amaurosis (LCA). Recent molecular studies in the English Springer Spaniel (ESS) dog have shown that PRA cases are often homozygous for a mutation in the RPGRIP1 gene, the defect also causing human RP, LCA, and cone rod dystrophies. The present study characterizes the disease in a group of affected ESS in USA, using clinical, functional, and morphological studies. An objective evaluation of retinal function using electroretinography (ERG) is further performed in a masked fashion in a group of American ESS dogs, with the examiner masked to the genetic status of the dogs. Only 4 of 6 homozygous animals showed clinical signs of disease, emphasizing the need and importance for more precise studies on the clinical expression of molecular defects before utilizing animal models for translational research, such as when using stem cells for therapeutic intervention.

show abstract

“…The purpose of the present study was therefore to compare three different anesthetic combinations frequently used clinically in dogs: thiopental-isoflurane, medetomidine-ketamine, and xylazine-ketamine, using the dog ERG protocol recommended by ECVO [19] in the same MS under similar laboratory conditions.…”

Section: Introductionmentioning

confidence: 99%

Comparison of the effects of three different combinations of general anesthetics on the electroretinogram of dogs

et al. 2009

Self Cite

View full text Add to dashboard Cite

The objective of this study is to compare the effects of three different anesthetic combinations on the electroretinogram in the same animals under similar laboratory conditions. Thiopental-isoflurane (TI), medetomidine-ketamine (MK), and xylazine-ketamine (XK) were used on each of 12 healthy miniature schnauzer dogs (MS) with a period of at least 3 weeks in between subsequent anesthesia protocols, using the Dog Standard Protocol. The scotopic ERGs consisted of scotopic low stimulus strength (S) responses designated S1, S2, S3, S4, and S5, at 1, 5, 10, 15, and 20 min after dark adaptation, respectively, and scotopic standard stimulus strength (S-ST) responses. The photopic ERGs consisted of a photopic single flash (P) response and 31 Hz flicker (P-FL) responses. For S-ST (2.5 cd s/m(2)), the amplitude of the a-wave using TI was significantly lower than that using MK (adjusted P = 0.05) and XK (adjusted P = 0.03), and the implicit time of the a-wave was significantly shorter than that using MK (adjusted P = 0.04). For P (2.5 cd s/m(2)), the amplitude of the b-wave using XK was significantly higher than that using MK (adjusted P = 0.01). The implicit times of the b-wave using TI was significantly longer and shorter than that of MK for S1, S2 and P-FL and for S4 and S-ST, respectively, and than that of XK for S2 and P-FL and for S5 and S-ST, respectively. The results of the present study showed that TI affected both the amplitude and the implicit time of the a-wave for S-ST and the implicit time of the b-wave relatively more so than was the case when using XK or MK. Therefore, it appears that either XK or MK could be advantageous to use rather than TI for clinical studies.

show abstract

Untitled

Cited by 99 publications

References 6 publications

Pupillary light reflex deficits in a canine model of late infantile neuronal ceroid lipofuscinosis

Pupillary light reflex deficits in a canine model of late infantile neuronal ceroid lipofuscinosis

Assessment of Hereditary Retinal Degeneration in the English Springer Spaniel Dog and Disease Relationship to anRPGRIP1Mutation

Comparison of the effects of three different combinations of general anesthetics on the electroretinogram of dogs

Contact Info

Product

Resources

About