Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “retinal development”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 919 records · Page 51Linked to original sources
PubMed2002

Systematic analysis of E-, N- and P-cadherin expression in mouse eye development.

Cadherins are a family of Ca(2+)-dependent cell adhesion molecules. Through their homophilic binding interactions, cadherins play important roles in tissue formation and maintenance during development. Here the authors compare the expression patterns of the three classical cadherins, E-, N- and P-cadherin, during mouse eye development from embryonic day 9.5 (E9.5) to adult. It was found that: (1) The expression patterns of N- and P-cadherin are mutually exclusive in most ocular tissues during development. N-cadherin mRNA is detected specifically in the lens placode during lens induction at E9.5, and is absent in the rest of the surface ectodermal tissues. In contrast, P-cadherin is expressed in the surface ectoderm but not in the lens vesicle. N-cadherin is expressed continuously in the lens pit, lens vesicle, and in the epithelial cells and newly differentiating fiber cells of the mature lens. P-cadherin is expressed in the epithelial cells of the cornea, eyelids and Harderian gland. Reciprocal expression patterns of N-and P-cadherins are also seen during retinal development. N-cadherin is initially expressed in both the inner and outer layers of the optic cup at E9.5. N-cadherin expression persists in the inner layer as it develops into neural retina, but is turned off in the outer layer where the cells differentiate into retinal pigment epithelial (RPE) cells and express P-cadherin. Reciprocal patterns of expression are also seen in the ciliary epithelium. N-cadherin is expressed in the inner layer and P-cadherin in the outer layer of the ciliary epithelium. (2) E- and P-cadherins are epithelial cadherins. Their expression patterns in the eye are not identical. Both cadherins are found in the epithelia of the cornea, eyelid and Harderian gland. In contrast, lens epithelial cells express E- but not P-cadherin, and RPE cells express P- but not E-cadherin. (3) In addition to its high expression in surface ectoderm-derived tissues, E-cadherin mRNA was also detected in some of the retinal ganglion neurons at postnatal day 14 (P14). E-cadherin expression in the neural retina has not been reported before. This study shows that cell fate determination in the eye occurs in conjunction with distinct changes in the patterns of cadherin gene expression.

Animals↗
PubMed2002

Retinal detachment in eyes with vitreous loss and an anterior chamber or a posterior chamber intraocular lens: comparison of the incidence.

PURPOSE: To compare the incidence of retinal detachment within 6 months of cataract surgery complicated by vitreous loss in eyes with a posterior chamber intraocular lens (PC IOL) or an anterior chamber IOL (AC IOL). SETTING: Department of Ophthalmology, Kaplan Medical Center, Rehovot, Israel. METHODS: In this retrospective consecutive nonrandomized comparative case series, all cases of cataract surgery complicated by vitreous loss between January 1991 and March 1998 were reviewed. Included were patients who had thorough anterior vitrectomy and primary IOL implantation and at least 6 months follow-up. Exclusion criteria were congenital and traumatic cataract, previous intraocular surgery, and previous retinal detachment. Patients receiving an unsutured single-piece poly(methyl methacrylate) (PMMA) PC IOL formed the PC group, while those receiving flexible open-loop single-piece PMMA AC IOLs formed the AC group. The incidence of postoperative retinal detachment in the 2 groups was compared. RESULTS: Of the 151 eyes of 149 patients, 66 received a PC IOL and 85 received an AC IOL. Two eyes (3.0%) in the PC group and 2 (2.4%) in the AC group developed retinal detachment; the difference between groups was not statistically significant (P = 1.00, Fisher exact test). CONCLUSIONS: In eyes that have vitreous loss and thorough anterior vitrectomy, AC IOL implantation did not appear to increase the incidence of retinal detachment.

Aged↗
PubMed2000

Regulation of FGF soluble receptor type 1 (SR1) expression and distribution in developing, degenerating, and FGF2-treated retina.

The spatial and temporal patterns of expression and content of the fibroblast growth factor (FGF) soluble receptor SR1, a specific inhibitor of FGF, were investigated during embryonic and postnatal development of the retina in Fisher rats. As early as at embryonic day 18 (E18), SR1 mRNA and protein were detected in the retina. SR1 protein was strongly associated with the differentiating ganglion cells and its distribution paralleled the radial pattern of retinal development, from center to periphery. From E18 to postnatal day 5, the levels of both SR1 mRNA and SR1 protein remained constant. Thereafter, they decreased rapidly, by a factor of 5 in the adult retina. SR1 was labeled in the inner nuclear layer, but never in the photoreceptor nuclei. In the neural retina of RCS dystrophic rats, the levels SR1 mRNA and SR1 protein were 2 to 3 times higher than those in the normal congenic controls, before and during photoreceptor degeneration. These results provide the first evidence that a natural FGF inhibitor is regulated during retina development and degeneration and suggest that changes in SR1 content may be involved in the regulation of FGF activities in retina. This was confirmed in vivo in RCS rats, in which delayed photoreceptor apoptosis by intravitreal injection of FGF2 was accompanied by a downregulation of SR1 expression. Dev Dyn 2000;217:24-36.

Animals↗
PubMed2000

Ectopic expression of Msx2 in chick retinal pigmented epithelium cultures suggests a role in patterning the optic vesicle.

During the initial stages of vertebrate retinogenesis, cells of the optic vesicle adopt one of two alternate cell fates. Cells in the distal-most part of the vesicle, immediately beneath the surface ectoderm, undergo neural differentiation; cells in the proximal part differentiate into retinal pigmented epithelial cells. The mechanisms that establish this pattern of differentiation are poorly understood. In the mouse embryo, Msx2, a homeobox-containing transcription factor, is expressed in cells of the optic vesicle that will form the neural retina, whilst the developing retinal pigmented epithelium (RPE) does not express this gene. Msx2 could therefore be involved in patterning the optic vesicle into neural and pigmented domains. To explore this possibility we ectopically expressed mouse Msx2 in cultures of chick RPE cells. Compared with cultures transfected with a control construct, Msx2-transfected cultures contained fewer cells expressing the RPE marker, Mitf, and more cells expressing class III beta-tubulin, a neuronal marker. In addition a small proportion of Msx2-transfected cells acquired a neural-like morphology. These results show that Msx2 can suppress the differentiated state of RPE cells and promote their differentiation into neural cell types. We suggest that Msx2 may pattern the optic vesicle into neural and pigmented domains by affecting the balance between RPE and neural retina differentiation.

Animals↗
PubMed2004

P23H and S334ter opsin mutations: Increasing photoreceptor outer segment n-3 fatty acid content does not affect the course of retinal degeneration.

PURPOSE: The n-3 polyunsaturated fatty acids (PUFA) facilitate retinal development and function. Rats carrying transgenes with P23H and S334ter rhodopsin mutations lose their photoreceptors and have lower levels of 22:6n-3 in rod photoreceptor outer segments (ROS) than wild type (WT) animals. We tested the hypothesis that the rate of retinal degeneration in these mutant animals could be sensitive to the n-3 fatty acid content of retina. METHODS: Beginning embryonic day 15, WT and heterozygous transgenic rats with P23H and S344ter rhodopsin mutations were fed semi-synthetic diets enriched in n-6 (safflower oil, SO) or n-3 (flaxseed oil, FO) PUFA. At 35 and 55 days of age, electroretinographic (ERG) response, outer nuclear layer (ONL) thickness, and fatty acid composition of plasma and ROS were determined. Student's t-tests and multivariate analysis of variance with post hoc tests determined statistical differences. RESULTS: Rats fed FO or SO diets had different n-6/n-3 PUFA ratios in plasma (1.3 and 62) and ROS (0.2 and 1.1, respectively). Although there were profound effects of the diets on the plasma fatty acid composition, there were only minor differences between WT and transgenic animals within each dietary regime. The ROS of FO fed rats had 70% more 22:6n-3 than those fed SO, and the WT had higher concentrations of 22:6n-3 than the transgenic animals (WT>P23H>S334ter). In contrast, there was no difference in 22:6n-3 levels in ROS of WT and transgenic rats fed the SO diet. At P55, both transgenic lines had diminished ERGs and ONL thickness relative to the WT. There was no detectable effect of ROS fatty acid enrichment on the rate of retinal degeneration in the transgenic animals. However, the FO-diet provided a modest protection of function (b-wave) in S334ter animals. CONCLUSIONS: Feeding n-3 fatty acids to rats with mutant rhodopsin transgenes significantly increased the levels of 22:6n-3 in ROS membranes, but had no effect on the rate of retinal degeneration. Therefore, the degeneration is not the result of low (or high) 22:6n-3 in ROS and supplementation with 18:3n-3 will not rescue dying photoreceptor cells in these animal models of inherited retinal degenerations.

Animals↗
PubMed1990

Stimulatory effects of retinal extract and fibroblast growth factor on lentoidogenesis in cultures of chick embryo neuroretinal cells.

A crude extract prepared from embryonic chick retina stimulates growth and particularly transdifferentiation into lens when added as a supplement to neuroretinal (NR) cultures in vitro. This effect is especially marked when using a medium (H) containing 5% horse serum, where growth factors are likely to be limiting. The level of delta-crystallin (lens marker) production in such cultures increases with the concentration of extract. Using extracts from earlier and later stages of retinal development, there is an age-dependent decline in the extent to which transdifferentiation is stimulated. However, such extracts have little effect on the activity of CAT, a neuronal marker enzyme. These effects are most probably mediated by growth factors present in the retinal extract acting upon Müller glial cells or their precursors in the NR cultures. In support of this suggestion, we show that purified fibroblast growth factor (but not epidermal growth factor) exerts similar effects on both culture growth and delta-crystallin accumulation.

Age Factors↗
PubMed1997

Vsx-1 and Vsx-2: two Chx10-like homeobox genes expressed in overlapping domains in the adult goldfish retina.

The genetic linkages of the murine ocular retardation mutation with the Chx10 gene and the murine small eye mutation with the Pax-6 gene has demonstrated the importance of Paired class homeobox genes in the development of the mammalian retina. Previously, we identified a Paired-class homeobox gene, Vsx-1, whose expression in the adult goldfish retina is restricted to the inner nuclear layer (INL) and to postmitotic, differentiating progenitor cells in the growth zone at the retinal peripheral margin, where neurogenesis continues throughout life. Here, we report the molecular cloning and expression pattern of a new Paired class homeobox gene, Vsx-2, in the adult goldfish retina. Like Vsx-1, Vsx-2 expression is highly restricted to the retina in the adult goldfish and overlaps with Vsx-1 expression in the mature INL. At the peripheral margin, Vsx-2 is expressed in mitotically active neuronal progenitors and is downregulated as these cells become postmitotic and begin to differentiate. Comparison of the amino acid sequences of Vsx-2, Vsx-1, Chx10, and C. elegans ceh-10 reveal a conserved homeodomain and a unique domain termed the CVC domain. The similarities of the Vsx-2, Vsx-1, and Chx10 expression patterns suggest that genes containing the CVC domain have conserved functions during retinal development in vertebrates.

Amino Acid Sequence↗
PubMed1991

[Sudden blindness in an AIDS patient. Simultaneous infection with cytomegalovirus and herpes simplex viruses and development of malignant non-Hodgkin lymphoma].

A 50 year old patient with non-diagnosed HIV-infection at onset of his illness developed impairment of vision and temporary double vision combined with severe hemianopsia. With normal fundus and suspicious Herpes simplex iritis therapy with Acyclovir was started. Primarily the patient showed a good response to the therapy and loss of vision could be prevented. After 4 weeks CMV-retinitis developed. In spite of Gancyclovir therapy manifestation of total loss of vision after 6 weeks. Autopsy demonstrated signs of simultaneous a CMV-infection of the retina and a herpes simplex-infection of the optic nerve combined with a Non-Hodgkin-Lymphoma of the optic tract.

Acquired Immunodeficiency Syndrome↗
PubMed2003

Double cone dystrophy and RPE degeneration in the retina of the zebrafish gnn mutant.

PURPOSE: To characterize morphologic alterations in the retina of the visual mutant zebrafish gantenbein (gnn) and to examine whether these alterations correlate with those present in human hereditary eye diseases. METHODS: The gnn mutant was isolated by behavioral and macroscopic screening. Retinas of gnn zebrafish larvae were examined at different developmental stages from 2 to 9 days postfertilization (dpf) by standard histologic staining techniques and by immunocytochemistry. Ultrastructural alterations were examined by electron microscopy. The genetic map position of the induced mutation was identified by mapping with two candidate primer pairs on single larvae. RESULTS: The gnn mutant exhibited shortened outer photoreceptor segments and altered RPE morphology. In the photoreceptor layer of the mutant, the total number of lectin-labeled cones was reduced in all developmental stages from 2 to 7 dpf, whereas the amount of rhodopsin-positive cells remained at the wild-type (WT) level. Labeling with zebrafish opsin antibodies revealed dystrophic red cones at 5 dpf, whereas the morphology of all other cone types was largely unaffected. Electron microscopy unveiled electron-dense deposits between the discs of the double cone outer segments. In addition, the onset of progressive RPE degeneration was observed at this stage of development. At later stages, all cone types and the RPE became degenerative. The morphology of distinct second-order neurons remained largely unaffected by the mutation. The gnn mutation was located approximately 4.3 cM from the simple sequence length polymorphism (SSLP) marker Z15453 on linkage group 16. CONCLUSIONS: In gnn mutant zebrafish, cones, and especially red cones, are dystrophic in early retinal development. Subsequent to this cone dystrophy, the RPE becomes dysfunctional and starts to degenerate in later stages of development. Thus, the early developmental morphology of gnn exhibits similarities to cone dystrophies most commonly seen in age-related macular degeneration (AMD) among humans, whereas the later stages of degeneration in gnn resemble RPE alterations in retinitis pigmentosa (RP) in humans. The gnn zebrafish mutant may therefore be a useful model for examining the possible interplay and connection between cone dystrophy and RPE degeneration.

Animals↗
PubMedDate not supplied

Expression of GABA in the fetal, postnatal, and adult human retinas: an immunohistochemical study.

The expression of GABA in the human fetal (12-25 weeks of gestation), postnatal (five-month-old), and adult (35-year-old) retinas was investigated by immunohistochemistry. GABA expression was seen as early as 12 weeks in the undifferentiated cells of the inner neuroblast zone; a few optic nerve fiber layer axons were clearly labeled, suggesting that some of the stained cell bodies were prospective ganglion cells, others could be displaced amacrine cells. From 16-17 to 24-25 weeks, intense labeling was found in the amacrine, displaced amacrine, and some ganglion cells. During this time period, horizontal cells (identified by calbindin immunohistochemistry), undergoing migration (periphery) and differentiation (center), expressed GABA prominently. In the postnatal retina, some horizontal cells were moderately labeled, but very weakly in a few cells, in the adult. The Müller cells developed immunoreactivity first weakly at 12 weeks and then moderately from 16-17 weeks onward. The staining was also evident in the postnatal and adult retinas, showing labeled processes of these glial cells. Virtually no axons in the adult optic nerve and nerve fiber layer were stained; the staining was restricted to a few, large ganglion cells and displaced amacrine cells: Some amacrines were also labeled. The possibility that GABA might play a role in horizontal cell differentiation and maturation is highlighted. Other evidences suggest that GABA might play a role in metabolism during retinal development.

Adult↗
PubMed2006

The developmental expression of K+ channels in retinal glial cells is associated with a decrease of osmotic cell swelling.

A major function of glial cells is the control of osmotic and ionic homeostasis, mediated by K+ and water movements predominantly through inwardly rectifying K+ (Kir) and aquaporin water channels. It has been suggested that K+ currents through Kir channels are implicated in the regulation of glial cell volume. Here, we investigated whether the developmental increase in Kir channel expression in Müller glial cells of the rat retina is associated with an alteration of cell volume regulation under anisoosmotic conditions. Around the time of eye opening at postnatal day (P) 15, developing retinal glial cells fully alter the profile of their membrane conductances, from a current pattern with prominent fast transient K+ and Na+ currents to a pattern of noninactivating currents through Kir and delayed rectifier K+ channels. Concomitantly, aquaporins-1 and -4 are expressed in the developing retina. This is accompanied by a conspicuous alteration of the swelling characteristics of cells; somata of immature glial cells in early postnatal retinas (P5-P15) swell under hypotonic stress but no swelling is inducible in mature cells at P18 and thereafter. However, glial cells at all developmental stages swell when their Kir channels are blocked by Ba2+. The postnatal maturation of Kir channel currents and volume regulation in retinal glial cells is delayed by visual deprivation. The data suggest that Kir channels are crucially involved in osmotic volume homeostasis of mature glial cells, and that the absence of Kir channels in immature cells is a major cause of their insufficient volume regulation.

Animals↗
PubMed1995

Localization of a fatty acid binding protein and its transcript in the developing chick retina.

The undifferentiated chick retina has elevated levels of fatty acid binding protein (R-FABP) mRNA. Tissue maturation is accompanied by a 50-100-fold decrease in transcript levels. To determine the location of the R-FABP transcript and its encoded protein in the developing retina, in situ hybridization and immunohistochemical analyses were carried out using chick embryos at different stages of development. The R-FABP mRNA and protein were found throughout the retina from day 3 to day 7 of incubation. Accumulation of R-FABP in the neurites of ganglion cells could readily be detected at early developmental stages. By day 11, R-FABP transcript levels were considerably reduced in the retina, while the protein was primarily found in the inner nuclear layer, inner plexiform layer and optic nerve fiber layer of the retina. As well, R-FABP mRNA and protein were abundant in the non-pigmented ciliary epithelium, which represents the forward prolongation of the retina in the anterior eye. Immunoelectron microscopy revealed the presence of R-FABP in both the nucleus and cytoplasm of day 4 retinal cells. In the day 13 retina, R-FABP was abundant in the processes of neuronal cells. These results suggest that, early in retinal development, there is a requirement for FABP in the nucleus as well as the cytoplasm of all retinal cells. At later stages, the concentration of R-FABP in the processes of neuronal cells would suggest a biochemical or structural role related to neurite extension and synapse formation.

Animals↗
PubMed1993

A pilot study of sequential therapy with zidovudine plus acyclovir, dideoxyinosine, and dideoxycytidine in patients with severe human immunodeficiency virus infection.

A pilot study was initiated to explore a sequential combination antiretroviral regimen in 21 patients with AIDS or advanced human immunodeficiency virus (HIV) infection, who had received little or no prior anti-HIV therapy. The mean entry CD4 cell count was 184/mm3. Patients received 3-week cycles consisting of zidovudine plus acyclovir, dideoxyinosine, and dideoxycytidine for 1 week each. Overall, the regimen was well tolerated for up to 3 years. The principal toxicities were anemia, nausea, and vomiting; 1 patient developed retinal lesions. The mean CD4 cell count reached a peak of 64 cells/mm3 above baseline at week 8 (P = .005 compared to baseline) and remained above baseline for > 40 weeks. Patients also gained weight and had decreases in serum HIV p24 antigen. Eight patients developed opportunistic infections or tumors. Only 4 patients died during 3 years of follow-up. This regimen appears to be generally tolerable and to have anti-HIV activity. Additional studies will be needed, however, to learn how to best combine the available agents in patients with HIV infection.

AIDS-Related Complex↗
PubMed2000

Late retinal progenitor cells show intrinsic limitations in the production of cell types and the kinetics of opsin synthesis.

The seven major cell classes of the vertebrate neural retina arise from a pool of multipotent progenitor cells. Several studies suggest a model of retinal development in which both the environment and the progenitor cells themselves change over time (). To test this model, we used a reaggregate culture system in which a labeled population of progenitor cells from the postnatal rat retina were cultured with an excess of embryonic retinal cells. The labeled cells were then assayed for their cell fate choices and their kinetics of rod differentiation, as measured by opsin synthesis. The kinetics of opsin synthesis remained unchanged, but fewer postnatal cells adopted the rod cell fate when cultured with embryonic cells. There was an increase in the percentage of bipolar cells produced by postnatal progenitor cells, indicating a possible respecification of fate. The increase in bipolar cells could occur even after progenitor cells had completed their terminal mitoses. These alterations in cell fates appeared to be caused at least in part by a secreted factor released by the embryonic cells that requires the LIFRbeta/gp130 complex for signaling. Finally, although surrounded by 20-fold more embryonic cells, the postnatal cells did not choose to adopt any fates normally produced only by embryonic cells.

Animals↗
PubMed2005

Oxygen modifies artery differentiation and network morphogenesis in the retinal vasculature.

The mechanisms that control differentiation of immature blood vessels into either arteries or veins are not well understood. Because oxygen tension in arteries is higher than in veins, oxygen has the potential to be an instructive signal for artery/vein (AV) differentiation. We test this hypothesis by exposing newborn mice to moderate hypoxia (10% atmospheric oxygen) and studying AV differentiation in the developing retinal vasculature. Forming retinal arteries fail to express the artery-specific markers Delta-like 4 (Dll4) and EphrinB2 during hypoxia. However, other aspects of AV differentiation are retained such as high levels of alpha smooth muscle actin in arterial mural cells and vein-specific expression of the msr/apj gene. The capillary network between arteries and veins is denser, and capillaries expressing the venous marker msr/apj are found in territories normally occupied by arterial capillaries. Thus, it appears that high oxygen in arterial blood is required for arterial expression of Dll4 and EphrinB2, which could be involved in cell-cell repulsion pathways that dictate the normal segregation of arteries and veins.

Animals↗
PubMed1992

Immunocytochemical localization of parvalbumin- and neurofilament triplet protein immunoreactivity in the cat retina: colocalization in a subpopulation of AII amacrine cells.

Using antibodies against parvalbumin and neurofilament triplet protein, colocalization of these two neuronal markers was revealed in all of type A horizontal cells and alpha ganglion cells and in a small number of AII amacrine cells of the cat retina. Besides the double-labeled neurons, parvalbumin alone was present in type B horizontal cells, in small numbers of starburst- and A13-like amacrine cells and in the somata of unidentified ganglion cells. The processes of the double- or single-labeled amacrine cells did not have a continuous retinal cover. Although the parvalbumin- and neurofilament-immunolabeled amacrine cells belonged to groups of neurons with well-defined cell morphologies, their neurochemical features differed from other AII, starburst and A13 amacrine cells. The presence of these cells may be due to an accidental expression of an unusual combination of neurochemical features during retinal development. It is also possible that these cells support the functioning of ganglion cells with rarely occurring complex receptive fields.

Animals↗
PubMed1983

Reduced ocular glucose transport and increased non-electrolyte permeability in rats with retinal degeneration (RCS).

The transport kinetics across the plasma-ocular barriers of labeled molecules including urea, D-glucose, 3-0-methyl-D-glucose, L-glucose, and sucrose were studied in adult RCS rats and compared to control albino Sprague-Dawleys (SD). Results indicate that substances that passively cross the plasma-aqueous and plasma-vitreous barriers (urea, sucrose, L-glucose) do so more readily in the RCS rat especially via the trans-retinal route. By contrast, D-glucose, which penetrates the ocular barriers of the control rat by a carrier-mediated mechanism was found to cross the ocular barriers of the RCS rat at a reduced rate. Thus, the ocular barriers of the RCS rat with well developed retinal degeneration demonstrate an increase in passive permeability and a reduction in ability to perform their membrane transport function (D-glucose). The permeability defect was more pronounced in the blood-vitreous barrier than in the blood-aqueous barrier.

3-O-Methylglucose↗
PubMed2005

5-HT2B-mediated serotonin signaling is required for eye morphogenesis in Xenopus.

In this paper, we show that serotonin, via 5-HT2B receptor, is involved in Xenopus retinal histogenesis and eye morphogenesis by supporting cell proliferation and survival. To analyze the 5-HT2B function in retinal development, we performed a loss-of-function study using both a pharmacological and a morpholino antisense oligonucleotide approach. Gain-of-function experiments were made by microinjecting 5-HT2B mRNA. Misregulation of the 5-HT2B receptor activity causes alterations in the proliferation rate and survival of retinal precursors, resulting in abnormal retinal morphology, where lamination is severely compromised. Clones derived from lipofected retinoblasts that overexpress 5-HT2B show an increase in the relative percentage of ganglion cells, possibly due to protection from apoptosis. This effect is reversed in clones lipofected with a 5-HT2B-specific morpholino. We hypothesize that the survival of the correct number of ganglion cells is controlled by 5-HT/5-HT2B signaling. Serotonin, acting as a neurotrophic factor, may contribute by refining retinal connectivity and cytoarchitecture.

Animals↗