Retinal oxalosis. A clinicopathologic report.

A 55-year-old woman with chronic renal failure treated with hemodialysis had severe bilateral visual loss develop due to retinal ischemia. Ophthalmoscopy showed crystals in the distribution of the retinal arteries, but not veins, and this led to a diagnosis of systemic oxalosis. Factors contributing to systemic oxalosis in addition to renal failure were ascorbic acid dietary supplementation, pyridoxine deficiency, and ileal resection.

Alpha transducin is present in blue-, green-, and red-sensitive cone photoreceptors in the human retina.

Phototransduction in vertebrate rod and cone photoreceptor cells involves G protein-mediated light stimulation of cGMP hydrolysis. Enzymes of the cGMP hydrolysis cascades of rods and cones are products of different genes. Three different classes of cones in the human retina are maximally sensitive to either blue, green, or red light.

Aspergillus necrotizing retinitis. A clinico-pathologic study and review.

The authors describe a case of bilateral acute necrotizing retinitis caused by Aspergillus fumigatus in an immunocompromised host. The patient rapidly lose useful vision and expired from progressive systemic disease while on parenteral amphotericin B. Postmortem aqueous cultures were negative whereas vitreous cultures were positive.

Long-term corneal retention of a plant foreign body.

A fragment of sunflower stalk had been retained in the cornea of a 71-year-old man for 58 years. During initial healing of the wound, which included formation of a retrocorneal membrane over the foreign body in the anterior chamber, there was probably loss of endothelial cells. This probably predisposed the cornea to the endothelial decompensation that occurred following cataract extraction and implant of an intraocular lens 56 years after the foreign body first appeared in the cornea.

Standardized intravitreal injections: evaluation of the effect of anesthesia on rapid axonal transport in the optic nerve.

Retinal ganglion cells incorporate intravitreally injected [3H]leucine into proteins that are transported orthogradely in optic axons to the superior colliculus. Since optic projections in the albino rabbit are nearly totally crossed, an agent suspected to alter axonal transport can be applied to one optic nerve after bilateral intravitreal injection of [3H]leucine; any reduction in radioactivity transported to the contralateral superior colliculus can then be quantified. Such studies require symmetric uptake and incorporation of precursor into ganglion cell proteins.

Distribution of membrane proteins in mechanically dissociated retinal rods.

Solitary rods were isolated from frog retinas by mechanical dissociation. Typically, the rods cleave sclerad to the nucleus and consist of outer segments with attached partial inner segments with either tapered or rounded profiles. Light and electron microscopy reveal that the outer and inner segments of rods with tapered inner segments, like rods in the intact retina, are joined by a single connecting cilium.

Optic nerve head axonal transport in rabbits with hereditary glaucoma.

Rabbits with hereditary glaucoma develop ocular changes that resemble human congenital glaucoma and buphthalmia. The inheritance is autosomal recessive (bu). Previous research was performed primarily on albino bu/bu rabbits that were unhealthy and bred poorly.

Congenital iris cysts.

Unilateral, spontaneous, non-pigmented iris cysts appeared before the age of 2 years in four patients. Histopathological specimens obtained in three cases showed stratified to cuboidal, non-pigmented, epithelial lined cysts. Goblet cells were recognised in two of the three specimens.

Uveoretinitis in rabbits following immunization with interphotoreceptor retinoid-binding protein.

Interphotoreceptor retinoid-binding protein (IRBP) is a glycoprotein found in the interphotoreceptor matrix between the neurosensory retina and the retinal pigment epithelium and is thought to shuttle retinol among cells that border the interphotoreceptor space. Immunization of rabbits with bovine IRBP caused subsequent photoreceptor degeneration, as documented by light- and electron microscopy. Beginning on post-injection day 18, scattered regions had photoreceptor outer segments that were disorganized and shortened or absent.

Donor corneal endothelial striae.

Excessive traction during excision of donor corneoscleral buttons can result in damage or death to corneal endothelial cells. This damage manifests as multiple peripheral and, less commonly, central striae or stretch marks that correspond to linear opacities at the level of the endothelium. The striae consist of parallel lines of degenerate endothelium, each line three to eight cells wide, and stain readily with trypan blue, which is indicative of cell damage or death.

Identification of specific transducin alpha subunits in retinal rod and cone photoreceptors.

Transducin is a guanyl nucleotide-binding protein that couples rhodopsin photolysis to hydrolysis of guanosine 3',5'-monophosphate in rod photoreceptor cells of vertebrate retinas. Several complementary DNA clones encoding transducin subunits have recently been characterized. One clone, isolated from a bovine retina complementary DNA library, encodes a previously unidentified polypeptide with an amino acid sequence 78% identical to the sequence of the alpha subunit of bovine rod outer segment transducin.

Breakdown of the outer blood-retinal barrier in experimental commotio retinae.

An animal model has been developed in this study to produce commotio retinae (Berlin's edema) by means of standardized, non-penetrating B.B. pistol injury to the cornea.

'Leopard spot' retinopathy in Warburg syndrome.

A female infant with brain and muscle abnormalities characteristic of Warburg syndrome had an atypical retinal dysplasia which appeared clinically as a 'leopard spot' retinopathy. The retinal histology is described in detail and is remarkable for periodic thinning of the inner nuclear layers and for isolated rosettes in the periphery. We believe 'leopard spot' retinopathy is yet another ocular manifestation of the Warburg syndrome.

Retinal neovascularization in Potter's syndrome secondary to renal agenesis.

Abnormalities of retinal vascularization were observed in a male stillborn at 33 weeks gestation with Potter's syndrome secondary to renal agenesis. Each eye had a persistent tunica vasculosa lentis and hyaloid artery as well as enlarged intraretinal vessels and a sharply demarcated avascular peripheral retina. Light microscopy revealed marked proliferation of capillaries and mesenchymal spindle cells of the retina.

Zonulae adherentes pore size in the external limiting membrane of the rabbit retina.

The interphotoreceptor space (IPS) of the retina is bordered by the retinal pigment epithelium, photoreceptors, and Müller cells and surrounds the photoreceptor outer and inner segments. It contains a matrix composed of glycosaminoglycans and proteins, including interphotoreceptor retinol-binding protein (IRBP). The matrix does not diffuse sclerad through the tight junctions that link cells of the pigment epithelium or vitread beyond the point at which photoreceptors and Müller cells are linked by zonulae adherentes that comprise the external limiting membrane (ELM).

Localization of retinoid-binding proteins in developing rat retina.

Antibodies to cellular retinol-binding protein (CRBP) and cellular retinal-binding protein (CRALBP) were obtained from rabbits immunized with antigens purified from bovine retina. Antigens were localized on frozen sections of rat retina using indirect FITC immunofluorescence. In the retinal pigment epithelium of rats from postnatal day 1 (the day of birth) to postnatal day 32, specific staining with anti-CRBP was restricted to the cytoplasm; the nuclei were unstained.

Immunocytochemical localization of interphotoreceptor retinoid-binding protein in developing normal and RCS rat retinas.

Interphotoreceptor retinoid-binding protein (IRBP) was localized immunocytochemically in developing normal and RCS rat retinas. IRBP was present in normal and RCS neural retinas on the day after birth (postnatal day 2, P2) to P8 in the space between the neuroblastic layer and the retinal pigment epithelium (RPE). The presence of IRBP prior to the development of outer segments (OS) suggests that OS formation is not linked temporally with IRBP secretion.

cGMP phosphodiesterase in rod and cone outer segments of the retina.

Immunochemical, chromatographic, and sodium dodecyl sulfate gel electrophoresis studies suggest that immunologically related but distinct cyclic GMP phosphodiesterases are present in rod and cone outer segments of the retina. Immunocytochemical studies demonstrated that one monoclonal antibody (ROS-1) recognized a determinant present in both rod and cone outer segments, while another monoclonal antibody (ROS-2) only recognized rod outer segments. At least two peaks of phosphodiesterase activity could be separated by high-performance anion-exchange chromatography of retinal extracts.

Characterization of the interstitial space: immunocytochemical and biochemical studies.

The interstitial space has been characterized using immunocytochemical and biochemical techniques. The pore size of the external limiting membrane that forms the vitread margin of this extracellular space has been probed using a series of biotinylated proteins of known Stokes' radius, followed by avidin-horseradish peroxidase histochemistry. The pore size of the zonulae adherentes that collectively comprise the external limiting membrane has been found to lie between 30 and 36A.

Immunocytochemical localization of retinoid-binding proteins in developing normal and RCS rats.

Interstitial retinol-binding protein (IRBP), cellular retinol-binding protein (CRBP), and cellular retinal-binding protein (CRALBP) were localized in developing normal and RCS rat retinas. IRBP is found in the presumptive interphotoreceptor space in normal and RCS rats on P1. It reaches adult levels on P18.

Müller cell expression of glial fibrillary acidic protein after genetic and experimental photoreceptor degeneration in the rat retina.

Glial fibrillary acidic protein (GFAP) is normally found in astrocytes. In the normal rat retina at all ages, only astrocytes stain for GFAP. This staining pattern is also found in RCS rats with inherited retinal dystrophy younger than 38 days.

Immunologic characterization of the photoreceptor outer segment cyclic GMP phosphodiesterase.

High affinity (KD approximately 1 X 10(-9) M) monoclonal antibodies (ROS-1 and ROS-2) were prepared to bovine photoreceptor outer segment cGMP phosphodiesterase. ROS-1 immunoadsorbed greater than 95% of the cGMP phosphodiesterase activity from a detergent-solubilized bovine retina extract while ROS-2 immunoadsorbed only a subfraction of the same activity. Sodium dodecyl sulfate gel analysis of these immunoadsorbates demonstrated that ROS-1 and ROS-2 specifically adsorbed only peptides that comigrated with purified rod outer segment phosphodiesterase.