Retinal encoder

Another emphasis has been given to the design of optimal and appropriate adaptive stimulation with respect to the interindividual retinal degeneration in retinitis pigmentosa and the implantation site. An adaptive retinal encoder has been under development [45]. Adaptive visual fields are employed which are adjusted to the function of retinal ganglion cells. The arrangement of electrodes allows sophisticated stimulation procedures. The described retinal prosthesis is considered to be one of the most challenging adaptronic systems of the future. The first patients have been implanted in Europe and the USA... 

However, acyclic nucleotide analogs (acyclic nucleoside phosphonates) have been developed, which carry one phosphonate moiety and require only the two subsequent phosphorylation steps (De Clercq et al. 1978). Independent of virus-encoded kinases, they display a broader spectrum of efficacy. This class comprises important drugs against HIV (tenofovir) and HBV (adefovir, tenofovir), as well as cidofovir, which is approved for use against CMV retinitis, but also displays an exceptionally broad efficacy profile against many herpesviruses, adenovirus, poxviruses, and papillomaviruses (De Clercq and Holy 2005). 

Bieszke, J. A., E. L. Braun et al. (1999). The nop-1 gene of Neurospora crassa encodes a seven transmembrane helix retinal-binding protein homologous to archaeal rhodopsins. Proc. Natl. Acad. Sci. 96(14) 8034-8039. 

Nicoletti, A., D. J. Wong et al. (1995). Molecular characterization of the human gene encoding an abundant 61 kDa protein specific to the retinal pigment epithelium. Hum. Mol. Genet. 4(4) 641-649. 

Anderson, R. E., Maude, M. B., Alvarez, R. A, Acland, G. and Aguirre, G. D. A hypothesis to explain the reduced blood levels of docosahexaenoic acid in inherited retinal degenerations caused by mutations in genes encoding retina-specific proteins. Lipids 34, S235-S237,1999. 

Retinal responses to different light frequencies are encoded in the retina and conveyed to the thalamus and visual cortex 808... 

Downes, S.M., Payne, A.M., Kelsell, R.E., Fitzke, F.W., Holder, G.E., Hunt, D.M., Moore, A.T., and Bird, A.C. (2001b). Autosomal dominant cone-rod dystrophy with mutations in the guanylate cyclase 2D gene encoding retinal guanylate cyclase-1. Arch. Ophthalmol. 119 1667-1673. 

Mitochondrial disease. A mutation in a mitochondrial gene encoding a component of ATP synthase has been identified. People who have this mutation suffer from muscle weakness, ataxia, and retinitis pigmentosa. A tissue biopsy was performed on each patient, and submitochondrial particles were isolated that were capable of succinate-sustained ATP synthesis. First, the activity of the ATP synthase was measured on the addition of succinate and the following results were obtained. 

Leber hereditary optic neuropathy (LHON) is the most common mitochondrial disease and the first linked to maternal inheritance through a mutation in the mtDNA. LHON is characterized by bilateral subacute loss of central vision caused by focal degeneration of the retinal ganglion cell layer and of the optic nerve. After initial symptoms, both eyes are usually affected within 6 months. Approximately 50% to 60% of males and only 8% to 32% of females who possess the mtDNA mutation will actually develop this optic neuropathy. Nuclear-encoded factors that affect mtDNA expression, mtDNA products, or mitochondrial metabolism may modify the phenotypic expression of LHON. Genetic coimseling in LHON is complicated in that the amount of mutant mtDNA transmitted by heteroplasmic females cannot be predicted, and testing cannot predict which individuals will develop visual symptoms. ... 

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