Search PubMed⌕ Search

Biomedical subjects

B Wiggert

Publications and source records attributed to B Wiggert.

At least 145 records · Page 8Linked to original sources
PubMed1986

Uveitis induced in primates by interphotoreceptor retinoid-binding protein.

Interphotoreceptor retinoid-binding protein was found to be highly uveitogenic in primates. All six monkeys immunized with bovine interphotoreceptor retinoid-binding protein developed ocular inflammation. The main clinical changes were sheathing of retinal vessels and deep well-circumscribed yellow-white lesions. Histologic changes in the retina included shortening of the outer segments and foci of inflammation, which extended through all retinal layers. Particularly profound were the choroidal changes, such as severe inflammatory infiltration, which often formed focal granulomas with epithelioid and giant cells. Some granulomas had the structure of Dalen-Fuchs nodules. These structures and other histologic changes in the monkeys closely resemble those in uveitic conditions in humans, such as sympathetic ophthalmia or Vogt-Koyanagi-Harada syndrome. These findings show that antigen that localizes specifically in the retina may initiate an immunopathogenic process affecting mainly the choroid.

Animals↗
PubMed1986

Retinoblastoma. A clinical, immunohistochemical, and electron microscopic case report.

A 4-year, 9-month-old boy had a history of leukocoria of the right eye for approximately six months prior to admission. The other eye was normal. There was no family history of retinoblastoma. Funduscopy disclosed a large white mass extending from the nasal pars plana to the mid-pupillary zone and the posterior pole with a near total retinal detachment in the superior temporal quadrant. A B-scan ultrasound showed an echo dense area of the anterior portion of the mass. A CT scan showed intraocular tissue densities with no evidence of optic nerve involvement or extraocular extension. Immunohistochemistry of a fresh frozen portion of tumor revealed reactivity with antibodies directed against interphotoreceptor retinoid-binding-protein (IRBP), neuron-specific enolase, glial fibrillary acidic protein, S-antigen, focal reactivity with opsin, and scattered cytoplasmic staining for cyclic GMP and cyclic GMP phosphodiesterase. Biochemical analysis of fresh frozen tissue samples confirmed the presence of IRBP. Transmission electron microscopy disclosed occasional Flexner-Wintersteiner rosettes connected by zonula adherens-like junctions. These showed inner segment-like structures containing prominent mitochondria, portions of cilia and fragments of outer segment material. These data, along with the immunocytochemistry indicates a predominant neuronal nature of the tumor cells with significant photoreceptor-like differentiation.

Child, Preschool↗
PubMed1986

Retinitis pigmentosa: immunohistochemical and biochemical studies of the retina.

Several immunohistochemical and biochemical characteristics of retinas from two patients with retinitis pigmentosa (RP) were examined. Histochemically, interphotoreceptor retinoid-binding protein (IRBP) was found in the interphotoreceptor space in small areas of preserved peripheral retina, although enzyme-linked immunosorbent assay suggested that little IRBP was present. Antibodies to glial fibrillary acidic protein and factor VIII-related antigen corroborated retinal gliosis and retinal vessel attenuation, respectively, in the RP cases. Fibronectin showed similar staining in normal and affected tissue.

Aged↗
PubMed1986

Uveoretinitis and pinealitis induced by immunization with interphotoreceptor retinoid-binding protein.

Rats immunized with microgram amounts of interphotoreceptor retinoid-binding protein (IRBP), a glycoprotein which localizes specifically in the eye and pineal gland, developed uveoretinitis and pinealitis. The severity and onset of changes were found to be dose-related and to be enhanced by B. pertussis bacteria. In general, the inflammatory changes induced by IRBP resembled those provoked by S-antigen (S-Ag), but significant differences were noted between the two diseases. The possible usefulness of the new experimental autoimmune disease is discussed.

Animals↗
PubMed1986

Immunochemical distribution of interphotoreceptor retinoid-binding protein in selected species.

An enzyme-linked immunosorbent assay (ELISA) was used to quantitate interphotoreceptor retinoid-binding protein (IRBP) in tissues of monkey and other species using rabbit antiserum against monkey IRBP. A 1:7500 antiserum dilution was found optimal with the linear range extending to 250 micrograms IRBP/ml. The highest IRBP concentration was found in cannulation fluid of the monkey interphotoreceptor space, although vitreous and aqueous humors also contained IRBP. The presence of IRBP in the vitreous was confirmed by Western blot and 3H-retinol binding studies. The pineal gland of monkey and rat also was found to contain IRBP, as assessed by ELISA and immunocytochemistry; IRBP was below the limits of detection in turtle and chicken retina. IRBP levels were uniformly low in retinas of human cases with hereditary retinal degeneration, including retinitis pigmentosa (three cases) and choroideremia (two cases). The presence of IRBP in pineal as well as in the vitreous and aqueous humors may indicate a broader role for this putative retinoid-transport protein than previously suspected.

Animals↗
PubMed1985

Endogenous fatty acids are covalently and noncovalently bound to interphotoreceptor retinoid-binding protein in the monkey retina.

Interphotoreceptor retinoid-binding protein (IRBP) purified from monkey interphotoreceptor matrix contains relatively high concentrations of endogenous fatty acids, 6.51 mol/mol of protein. Sixty-five percent of the total fatty acid bound to IRBP was found to be noncovalently attached, with the remainder covalently bound. The fatty acids are not residual components of phospholipids or neutral lipids, as judged by microchemical methods. The major fatty acids bound to IRBP are: palmitic (35%), stearic (21%), palmitoleic (7%), oleic (29%), linoleic (6%) and docosahexaenoic acids (2%). These fatty acids account for about 90% of the total fatty acid bound to interphotoreceptor matrix proteins extracted with organic solvents. Thus, IRBP may function as an intercellular fatty acid carrier and may depend on the covalently bound fatty acids for anchoring in the outer leaflet of cell membranes.

Animals↗
PubMed1985

cDNA clones encoding bovine interphotoreceptor retinoid binding protein.

We have isolated a cDNA clone (lambda IRBP-1) for bovine interphotoreceptor retinoid-binding protein (IRBP) by immunological screening of a bovine retinal lambda gt11 cDNA expression library. This clone contained a cDNA insert 325 bp in length. A 250 bp fragment of this cDNA was used to screen a bovine retina lambda gt10 cDNA library, resulting in the isolation of two larger cDNA clones containing inserts of 2.5 kb (lambda IRBP-2) and 1.5 kb (lambda IRBP-3). Restriction endonuclease mapping revealed all three clones to have an EcoR I restriction site. The 250 bp fragment of lambda IRBP-1 and the 2000 bp fragment of lambda IRBP-2 both hybridized to a single bovine retinal mRNA species approximately 8 kb in length; there was no hybridization with either chicken lens or liver RNA. The amino acid sequence of a tryptic peptide from authentic IRBP has been obtained. The deduced amino acid sequence from the cDNA nucleotide sequence is the same as this authentic peptide. This definitively establishes the identity of the cDNA clones as encoding bovine IRBP.

Amino Acid Sequence↗
PubMed1985

Extracellular cGMP phosphodiesterase related to the rod outer segment phosphodiesterase isolated from bovine and monkey retinas.

A phosphodiesterase (PDE) has been characterized in the interphotoreceptor matrix (IPM) of light-adapted fresh bovine retinas. It is obtained through a gentle rinsing of the retinal surface under conditions where the light-activated rod outer segment (ROS) enzyme remains attached. The enzyme has an apparent native molecular weight of 350 000 by gel filtration and appears as a doublet at Mr 47 000 and 45 000 on sodium dodecyl sulfate-polyacrylamide gels. It has an apparent Km value for cGMP of 33 microM and an apparent Km value for cAMP of 2200 microM. It is activated 3-6-fold by protamine and over 40-fold by trypsin. Protamine has no effect on the Km for cGMP while trypsin decreases the Km for cGMP by a factor of 2. The enzyme occurs in at least two forms as evidenced by two distinct peaks of activity after gel electrophoresis under nondenaturing conditions. A heat-stable inhibitor is tightly bound to the enzyme. The inhibitor obtained from the IPM PDE inhibits 98% of the activity of the trypsin-activated ROS PDE: conversely, the inhibitor obtained by boiling the ROS PDE completely inhibits the trypsin-activated IPM enzyme. A high-affinity monoclonal antibody to the active site of the ROS PDE, ROS 1 [Hurwitz, R., Bunt-Milan, A.H., & Beavo, J. (1984) J. Biol. Chem. 259, 8612-8618], quantitatively absorbs the IPM PDE. These observations indicate a clear relationship between these two PDEs even though their location, sizes, and specific functions in the retina appear to be distinct.

3',5'-Cyclic-GMP Phosphodiesterases↗
PubMed1985

Isolation and characterization of monkey interphotoreceptor retinoid-binding protein, a unique extracellular matrix component of the retina.

The interphotoreceptor retinoid-binding protein (IRBP) has been isolated from monkey interphotoreceptor matrix (IPM). Following gentle washing of the IPM from the retinal surface, the protein was purified to homogeneity by concanavalin A-Sepharose affinity chromatography, ion-exchange high-performance liquid chromatography (HPLC), and size-exclusion HPLC. Bovine IRBP was purified similarly and compared with the monkey protein. Sedimentation equilibrium analysis yielded a molecular weight of 106 000 +/- 2900 for the native monkey protein. Sedimentation velocity analysis gave a sedimentation coefficient of 5.4 +/- 0.3 S and a frictional ratio of 1.59, indicating an asymmetrical molecular shape. IRBP contains neutral sugar, including fucose, and sialic acid; the glycoprotein nature of the proteins probably accounts for the microheterogeneity observed in the electrofocusing pattern of both bovine and monkey IRBP. Both IRBPs have isoelectric points between 6.0 and 7.0. The fluorescence emission lambda max of the bound ligand was 470 nm with excitation at 340 nm, while the excitation lambda max was 333 nm with emission at 470 nm, for monkey IRBP incubated with exogenous all-trans-retinol. The amino acid compositions of the monkey and bovine proteins are similar; nonpolar amino acids account for over 50% of the residues, which may explain the apparent hydrophobic nature of the isolated proteins. The amino-terminal analyses indicated considerable homology between the monkey and bovine IRBPs in this region and verified the purity of the isolated proteins. IRBP thus appears to be a unique, conserved glycoprotein of the retinal extracellular matrix that could serve as a retinoid-transport vehicle.

Amino Acid Sequence↗
PubMed1985

Butyrate enhances the synthesis of interphotoreceptor retinoid-binding protein (IRBP) by Y-79 human retinoblastoma cells.

The synthesis and secretion of interphotoreceptor retinoid-binding protein (IRBP) from Y-79 human retinoblastoma cells was investigated using immunocytochemistry and SDS-polyacrylamide gel electrophoresis. Indirect immunofluorescence of cells growing in monolayer culture for 11 and 13 days showed no significant IRBP staining although by SDS-polyacrylamide gel electrophoresis, a small amount of IRBP was detected in the culture medium, suggesting synthesis and extracellular secretion. Butyrate (2mM) treatment of cells starting on the eighth day of culture resulted in a dramatic increase of IRBP fluorescence 3-5 days after treatment. Treatment of cells in all conditions with 1 microM monensin for 3 h showed concentration of IRBP in the Golgi apparatus of about 10-20% of cells as proved by a double immunofluorescent technique, employing anti-IRBP antibody and wheat-germ agglutinin. Incubation of cells with either radiolabeled amino acids or glucosamine followed by analysis of cell cytosol and culture medium by SDS-polyacrylamide gel electrophoresis also confirmed that 1) IRBP is synthesized by the Y-79 cells and secreted into the medium and 2) its production is markedly increased by butyrate treatment. The enhancement of IRBP synthesis by butyrate suggests biochemical differentiation of Y-79 cells possibly into photoreceptor-like cells and offers a new system for studying the properties of this unique retinoid-binding protein and of factors that control its synthesis and secretion.

Amino Acids↗
PubMed1985

Dominantly inherited retinitis pigmentosa. Ultrastructure and biochemical analysis.

A 66-year-old white man had dominant retinitis pigmentosa. He developed progressive restriction of his visual field, night blindness, pallor of the optic discs, pigmentary retinopathy and posterior subcapsular cataracts. Postmortem examination of the eyes included electron microscopy and biochemical analysis of cyclic nucleotides and interphotoreceptor retinoid-binding protein (IRBP). Except for the fovea and periphery, the retina showed extensive gliosis and neuronal loss with loss of photoreceptor cells. The choriocapillaris was variably occluded in the regions of absent retinal pigment epithelium (RPE). In places, the pigment epithelium invaded the retina to the level of the internal limiting membrane. Biochemical analysis revealed that the interphotoreceptor retinoid-binding protein (IRBP), an important glycoprotein of the interphotoreceptor space, was virtually absent even in retinal areas where photoreceptor cells were still present. Cyclic nucleotide determinations indicated a decrease in the cyclic GMP concentration that reflected the general loss of photoreceptor elements. On the other hand the cyclic AMP levels in all retinal areas tested were abnormally elevated, indicating the possible involvement of this nucleotide in the pathogenesis of the disease.

Aged↗
PubMed1984

Synthesis of interphotoreceptor retinoid-binding protein (IRBP) by monkey retina in organ culture: effect of monensin.

Whole monkey retinas were incubated in short-term organ culture with either radiolabeled amino acids or glucosamine. Soluble retinal proteins and proteins in the culture medium were analyzed by SDS-poly-acrylamide gel electrophoresis. Fluorography showed that the interphotoreceptor retinoid-binding protein (IRBP), a 146,000 Mr glycoprotein localized in the extracellular matrix, is synthesized by the neural retina and rapidly secreted into the medium. Secretion is blocked by 10-5M monensin. No significant IRBP synthesis was observed in the pigment-epithelium-choroid complex. IRBP is thus the major component synthesized and secreted by the neural retina into the interphotoreceptor space. This, and its affinity for retinoid makes it a prime candidate for an extracellular retinoid transport vehicle.

Animals↗
PubMed1984

Interphotoreceptor retinoid-binding protein. Characteristics in bovine and monkey retina.

Evidence is presented for the presence of a unique retinoid-binding protein in the retinal interphotoreceptor space (IPS). The protein is a glycoprotein with an apparent native Mr of approx. 250,000 and subunit Mr of about 146,000. It is synthesized by the retina and appears to be quickly secreted into the IPS. The protein binds retinol endogenously and there is an apparent differential light-dark binding of the ligand. The protein will bind other retinoids as well as retinol and thus is not as ligand specific as is the cellular retinol-binding protein (CRBP). With the localization of this protein in the IPS and its relatively catholic taste in retinoid binding, it is reasonable to call it the interphotoreceptor retinoid-binding protein (IRBP). The protein may function as a retinoid transport vehicle between retina and pigment epithelium.

Animals↗
PubMed1984

Isolation and characterization of an unsaturated fatty acid-binding protein from developing chick neural retina.

An unsaturated fatty acid-binding protein has been isolated from the cytosol fraction of developing chick neural retina. It has a molecular weight of approximately 14,800 and specifically binds not only added radiolabeled arachidonic and oleic acids but has also been found to bind unsaturated fatty acids endogenously. This protein was detected in chick neural retina at all stages examined, from 8 to 16 days of development. It is also present in chick heart, brain, and retinal pigmented epithelium-choroid as well as in adult bovine neural retina. It is distinct from both cellular retinol-binding protein and cellular retinoic acid-binding protein on the bases of binding specificity and isoelectric point.

Amino Acids↗
PubMed1983

The presence of a soluble interphotoreceptor retinol-binding protein (IRBP) in the retinal interphotoreceptor space.

A new, gentle technique has been developed for washing of the retinal interphotoreceptor space (IPS) to obtain soluble components of the extracellular matrix (ECM). Using this method, we have determined that the major soluble constituent of monkey IPS is a 146,000 Mr glycoprotein, which binds [3H]retinol, sediments on sucrose gradients at 7S and has an Rf of 0.42 on native gel electrophoresis. Using size-exclusion high performance liquid chromatography, the apparent molecular weight of the native protein was calculated to be 250,000 daltons. In contrast to previous studies, no 15,000-dalton cellular retinol-binding protein (CRBP) or 33,000-dalton cellular retinaldehyde-binding protein (CRALBP) was observed in the IPS wash, indicating that these proteins are probably not involved in retinol transport between retina and pigment epithelium (PE). In the supernatant fraction of retinal homogenates that contains soluble intracellular proteins as well as extracellular constituents, the 146,000 Mr protein was closely associated with a 93,000 Mr protein that could be separated on SDS-gel electrophoresis; the 93,000 Mr protein was not found in the IPS wash. The 146,000 Mr interphotoreceptor retinol-binding protein (IRBP) may function in extracellular retinol transport in the IPS.

Animals↗