T. Michael Nork

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The distribution of carbonic anhydrase (CA) among human photoreceptors has been a topic of dispute. In our experiments, by modifying an established enzyme histochemical technique, reproducible staining was observed. Of the cones in the peripheral retina, 91% were positive for CA. The CA-negative (CA-) cones were absent within approximately 8 arc min of the(More)
PURPOSE S-antigen (48 kDa protein or arrestin) is known to be present in rod photoreceptors. Its localization in cones is less clear with several conflicting reports among various species examined. METHODS This study employed three different anti-S-antigen antibodies (a48K, a polyclonal antiserum and two monoclonal antibodies, MAb A9-C6 and MAb 5c6.47)(More)
OBJECTIVE To test a hypothesis of photoreceptor involvement in retinal ganglion cell (RGC) death in chronic glaucoma. METHODS Laser spots were applied to 6 eyes of 3 rhesus monkeys, causing focal destruction of the outer retina, including the photoreceptors. After 3 to 4 weeks, experimental glaucoma was induced in the right eyes of each monkey using argon(More)
BACKGROUND Retinoblastoma is the most common childhood tumor of the eye, arising from cells that are defective in both copies of the retinoblastoma susceptibility gene (RB1). Most retinoblastoma tumor cells eventually undergo programmed cell death (i.e., apoptosis); however, some cells can acquire the ability to metastasize and become immortal. Transfection(More)
PURPOSE This study was designed to test the hypothesis that photoreceptors are adversely affected in glaucoma. As a measure of this effect, we examined the levels of rod opsin, and red/green and blue cone opsin mRNAs in monkeys with experimental ocular hypertension and glaucoma and in human eyes from donors with diagnosed glaucoma. METHODS Experimental(More)
PURPOSE To compare the relative contribution of VEGF and TNF-alpha in the development of laser-induced choroidal neovascularization (CNV) in monkeys and to exploit the feasibility of topical use of suitable antibody fragments for the prevention of experimental CNV. METHODS To induce experimental CNV, small high-energy laser spots were used to treat(More)
  • T M Nork
  • 2000
PURPOSE First, to study the cellular mechanisms of acquired color vision loss in retinal detachment and diabetic retinopathy. Second, to learn why, in glaucoma, the type of color vision deficit that is observed is more characteristic of a retinal injury than it is of an optic neuropathy. Third, to test a hypothesis of photoreceptor-induced, ganglion cell(More)
ACKNOWLEDGEMENTS: We gratefully acknowledge Quantum Devices, Inc. (Barneveld, WI) for providing light emitting diode arrays with Quantum's High-Emissivity Aluminiferous Light-Emitting Substrate (HEALS®) technology for this project. Abstract Retinal injury and retinal degenerative diseases are a leading causes of visual impairment in the developed world.(More)
OBJECTIVE To characterize functional and anatomic sequelae of a bleb induced by subretinal injection. METHODS Subretinal injections (100 μL) of balanced salt solution were placed in the superotemporal macula of 1 eye in 3 cynomolgus macaques. Fellow eyes received intravitreal injections (100 μL) of balanced salt solution. Fundus photography, ocular(More)
PURPOSE We report, for the first time to our knowledge, dynamic movements of the vitreous membrane and peripheral choroid during accommodation, and age-related changes in the anterior sclera. METHODS We studied 11 rhesus monkeys (ages 6-27 years) and 12 human subjects (ages 19-65 years). Accommodation was induced pharmacologically in human subjects and by(More)