David G. W. Birch

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PURPOSE Relationships between the Lamb and Pugh model of transduction in single rod photoreceptors and the parameters derived from human rod a-waves are examined to evaluate transduction abnormalities in retinitis pigmentosa (RP) and cone-rod dystrophy (CRD). METHODS ERGs were obtained from 15 patients, 11 with RP and 4 with CRD, and from 15 normal(More)
Rim protein (RmP) is an ABC transporter of unknown function in rod outer segment discs. The human gene for RmP (ABCR) is affected in several recessive retinal degenerations. Here, we characterize the ocular phenotype in abcr knockout mice. Mice lacking RmP show delayed dark adaptation, increased all-trans-retinaldehyde (all-trans-RAL) following light(More)
During development, visual photoreceptors, bipolar cells and other neurons establish connections within the retina enabling the eye to process visual images over approximately 7 log units of illumination. Within the retina, cells that respond to light increment and light decrement are separated into ON- and OFF-pathways. Hereditary diseases are known to(More)
One of two orphan photoreceptor guanylyl cyclases that are highly conserved from fish to mammals, GC-E (or retGC1) was eliminated by gene disruption. Expression of the second retinal cyclase (GC-F) as well as the numbers and morphology of rods remained unchanged in GC-E null mice. However, rods isolated from such mice, despite having a normal dark current,(More)
Leber congenital amaurosis (LCA, MIM 204000) accounts for at least 5% of all inherited retinal disease and is the most severe inherited retinopathy with the earliest age of onset. Individuals affected with LCA are diagnosed at birth or in the first few months of life with severely impaired vision or blindness, nystagmus and an abnormal or flat(More)
PURPOSE To survey families with clinical evidence of autosomal dominant retinitis pigmentosa (adRP) for mutations in genes known to cause adRP. METHODS Two hundred adRP families, drawn from a cohort of more than 400 potential families, were selected by analysis of pedigrees. Minimum criteria for inclusion in the adRP cohort included either evidence of at(More)
The leading edge of the a-wave of the electroretinogram (ERG) was evaluated as a measure of human cone photoreceptor activity. The amplitude of the cone a-wave elicited by flashes of different energy was compared to the predictions of a class of models from in vitro studies of cone photoreceptors. These models successfully describe the leading edge of the(More)
Mutations in the retinal-expressed gene CRX (cone-rod homeobox gene) have been associated with dominant cone-rod dystrophy and with de novo Leber congenital amaurosis. However, CRX is a transcription factor for several retinal genes, including the opsins and the gene for interphotoreceptor retinoid binding protein. Because loss of CRX function could alter(More)
Full-field electroretinograms were obtained in 269 normal subjects with the International Standardization Protocol endorsed by the International Society for Clinical Electrophysiology of Vision and the National Retinitis Pigmentosa Foundation Inc. Log rod and cone amplitudes decreased exponentially with age in adults; amplitudes declined to one half those(More)
Ninety-four patients, 6 to 49 years old, with progressive forms of retinitis pigmentosa were examined at baseline and annually for three consecutive years with respect to visual acuity, kinetic visual fields, dark-adaptation thresholds, computer-averaged electroretinograms, and fundus photographs. A subset was recalled within two months of a given visit to(More)