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At least 1,135 records · Page 63Linked to original sources
PubMed1991

Tissue-specific and developmental regulation of rod opsin chimeric genes in transgenic mice.

Chimeric gene fusions between 4.4 kb of rod opsin 5' flanking sequence fused to a diphtheria toxin gene and 4.4 kb or 500 bp of rod opsin 5' flanking sequence fused to the E. coli IacZ gene were used to generate transgenic mice for analysis of cell type-specific expression and temporal and spatial distribution of reporter gene product during retinal development. Opsin-diphtheria toxin transgene expression evoked photoreceptor-specific cell death. The 4.4 kb opsin-IacZ transgene followed temporal and spatial gradients of expression that approximate opsin expression. The 500 bp opsin fragment targeted expression to photoreceptors, but expression was weaker and nonuniform, suggesting that elements located upstream may be required for enhanced and uniform spatial expression.

Animals↗
PubMed1994

Developmental expression of a novel murine homeobox gene (Chx10): evidence for roles in determination of the neuroretina and inner nuclear layer.

Few potential regulatory proteins of vertebrate retinal development have been identified. We describe a 39 kDa murine polypeptide (Chx10) with a homeodomain 82% identical to that of the nematode protein ceh-10. In the developing mouse, the Chx10 transcript is expressed throughout the anterior optic vesicle and all neuroblasts of the optic cup. In the mature retina, the Chx10 protein is restricted to the inner nuclear layer, in which its expression decreases from the outer to the inner margin. Chx10 transcripts are also detected in regions of the developing thalamus, hindbrain, and ventral spinal cord. The data suggest that Chx10 plays critical roles in the formation of the neuroretina and in the development and maintenance of the inner nuclear layer.

Amino Acid Sequence↗
PubMed2006

[Omega 3: is there a situation of deficiency in young children?].

This paper starts with a review of the metabolism of n-6 (omega6) and n-3 (omega3) fatty acids, the resulting eicosanoids (prostaglandins, leucotrienes, and thromboxanes), and the physiological functions they are involved in, with special emphasis on effects during pregnancy (such as possible benefits on fetal growth, prevention of hypertension of pregnancy, and prevention of premature labor). Attention is then turned to the key role for long-chain polyunsaturated fatty acids (LCPUFAs), most notably docosahexaenoic acid (DHA), in central nervous system and retinal cell membrane structure and in cerebral and retinal development. Massive maternofetal transfer of LCPUFAs occurs during the third trimester of pregnancy, so that maintaining an adequate intake of DHA during pregnancy is crucial. Preterm babies must receive sufficient amounts of DHA, either via breast milk or via formula supplemented with LCPUFAs, both of which prevent DHA levels from declining in blood and cerebral phospholipids. These two methods of achieving an adequate DHA intake ensure normal maturation of visual acuity and cognitive function, as shown by randomized controlled trials. Formula supplemented with fish oils rich in n-3 LCPUFAs but lacking a proportionate supply of arachidonic acid (ArA, 20: 4n-6) negatively affects somatic growth, confirming the need for an adequate ArA supply. Eicosapentaenoic acid (EPA) can also exert negative effects. Therefore, the best source of supplemental LCPUFAs may be oil from single-cell algae and microscopic fungi, which contains adequate amounts of DHA and ArA. In full term neonates, strong arguments support LCPUFA supplementation, despite continuing controversy generated by conflicting results from interventional studies. These discrepancies in study results may be ascribable to differences in study design, patient age, intervention duration, assessment tool sensitivity, and LCPUFA sources. In 1996, an amendment to the European Directive on infant formulas and follow-on formulas was developed to authorize LCPUFA supplementation and to specify appropriate ranges. As a result, formulas supplemented with DHA and ArA were introduced on the market. Pregnant and nursing women should be advised to maintain an adequate dietary intake of DHA in order to meet their increased needs and those of the fetus or infant.

Animals↗
PubMed2004

Cumulative labeling of embryonic mouse neural retina with bromodeoxyuridine supplied by an osmotic minipump.

I describe a method for providing cumulative label of bromodeoxyuridine (BrdU) to mouse embryos. Commercially available osmotic pumps, which release their contents at a steady rate, were implanted subcutaneously in the interscapular space of pregnant mice on embryonic day (E) 9.5-12.5. Survival times varied from 4h to 37 days. Tissues (embryonic and neonatal eyes and maternal intestine) were immunochemically labeled for BrdU and examined histologically. The first detectably labeled cells appeared 4-7h post-implantation (hpi) and all cycling cells were labeled for at least 7 days post-implantation (dpi). Retinal development appeared normal. Terminal deoxynucleotidyl transferase-mediated biotinylated UTP nick end labeling (TUNEL) stained retinas that had been exposed to BrdU showed no more apoptotic cells than those unexposed. I conclude that the maternally implanted osmotic pump successfully provides cumulative BrdU labeling in the mouse embryo.

Animals↗
PubMed2004

Cell-intrinsic regulators of proliferation in vertebrate retinal progenitors.

The proliferative expansion of retinal progenitor cells (RPCs) is a fundamental mechanism of growth during vertebrate retinal development. Over the past couple of years, significant progress has been made in identifying genes expressed in RPCs that are essential for their proliferation, and the molecular mechanisms are beginning to be resolved. In this review, we highlight recent studies that have identified regulatory components of the RPC cell cycle machinery and implicate a set of homeobox genes as key regulators of proliferative expansion in the retina.

Animals↗
PubMed2003

Pericyte production of cell-associated VEGF is differentiation-dependent and is associated with endothelial survival.

Pericytes have been suggested to play a role in regulation of vessel stability; one mechanism for this stabilization may be via pericyte-derived vascular endothelial growth factor (VEGF). To test the hypothesis that differentiation of mesenchymal cells to pericytes/smooth muscle cells (SMC) is accompanied by VEGF expression, we used endothelial cell (EC) and mesenchymal cell cocultures to model cell-cell interactions that occur during vessel development. Coculture of EC and 10T1/2 cells, multipotent mesenchymal cells, led to induction of VEGF expression by 10T1/2 cells. Increased VEGF expression was dependent on contact between EC-10T1/2 and was mediated by transforming growth factorbeta (TGFbeta). A majority of VEGF produced in coculture was cell- and/or matrix-associated. Treatment of cells with high salt, protamine, heparin, or suramin released significant VEGF, suggesting that heparan sulfate proteoglycan might be sequestering some of the VEGF. Inhibition of VEGF in cocultures led to a 75% increase in EC apoptosis, indicating that EC survival in cocultures is dependent on 10T1/2-derived VEGF. VEGF gene expression in developing retinal vasculature was observed in pericytes contacting newly formed microvessels. Our observations indicate that differentiated pericytes produce VEGF that may act in a juxtacrine/paracrine manner as a survival and/or stabilizing factor for EC in microvessels.

Animals↗
PubMed1989

Posterior chamber intraocular lens insertion during pars plana lensectomy and vitrectomy for complications of proliferative diabetic retinopathy.

We inserted posterior chamber lenses into 21 eyes with complications of diabetic retinopathy upon completion of pars plana lensectomy and vitrectomy in a single session. After the original surgery, two eyes developed retinal detachments and underwent vitrectomy revisions with scleral buckling, one eye had a fluid-gas exchange for residual vitreous cavity blood, one eye had supplemental laser treatment, and one eye had intraocular antibiotics for endophthalmitis. Six months later, postoperative vision was better in 16 of the 21 eyes (76%), the same in four eyes (19%), and worse in one eye (5%). In 16 eyes visual acuity was 20/200 or better, and in six eyes it was 20/40 or better postoperatively. Decreased vision was caused by preexisting macular disease; two eyes had corneal edema with iris neovascularization associated with residual retinal detachment. The procedure and lenses were well tolerated and provided good pseudophakic vision.

Adult↗
PubMed2001

Developmentally regulated expression of GABA receptor rho1 and rho2 subunits, L7 and cone-rod homeobox (CRX) genes in mouse retina.

In this study, we compared the temporal expression pattern of four retinal genes; rho1 and rho2 that encode subunits of GABA(c) receptors, L7 that encodes Purkinje cell protein and CRX that encodes the cone-rod homeobox transcription factor. A reverse-transcription-polymerase chain reaction (RT-PCR) strategy that generated a linear correlation between the amount of retinal RNA and the amount of amplified product was used to quantify transcripts from each gene. Results with this method showed that the rho1 and L7 have similar developmental patterns. Both exhibit basal level expression before P7. From P7 to P20, the RNA levels for both genes were increased about 12-fold. After P20, the RNA levels remained unchanged. Compared to rho1 and L7, expression of rho2 began later, since the rho2 RNA could not be detected until P10. At P10, the rho2 RNA level was about 10% of its level at P35. Expression of rho2 reached its peak at a later developmental stage compared to that of rho1 and L7. The different temporal patterns were confirmed by co-amplification of rho1, rho2, and L7 in a single PCR tube. CRX RNA was detected at embryonic day 15 (E15) and increased progressively, in agreement with a prior study using in situ hybridization. These data, combined with evidence that the tissue distribution of rho1 and L7 RNA in the CNS are similar, indicates that rho1 and L7 may share common transcriptional regulatory elements. Furthermore, the difference in the timing of rho subunit expression suggests that the subunit composition of GABA(c) receptors vary during retinal development.

Aging↗
PubMed2002

Supplemental transscleral diode laser cyclophotocoagulation after aqueous shunt placement in refractory glaucoma.

OBJECTIVE: To assess the outcome of supplemental transscleral diode laser cyclophotocoagulation after aqueous tube shunt placement to obtain effective intraocular pressure (IOP) control. DESIGN: Retrospective non-comparative case series. PARTICIPANTS: Twenty-one eyes in 21 subjects with uncontrolled IOP despite the presence of an aqueous tube shunt and maximally tolerated glaucoma medications. INTERVENTION: Supplemental transscleral diode laser cyclophotocoagulation was performed. MAIN OUTCOME MEASURES: Reduction of intraocular pressure and reduction of glaucoma medications. RESULTS: Twelve adults and nine children underwent supplemental transscleral diode cyclophotocoagulation and were followed postoperatively for a mean of 26.9 +/- 13.4 (standard deviation [SD]) months (range, 7-58 months). Average IOP was significantly reduced from a preoperative level of 35.7 +/- 14.7 (SD) mmHg to a postoperative level of 13.6 +/- 7.1 (SD) mmHg (P < 0.001) with the mean number of medications significantly reduced to 1.5 +/- 1.3 (SD) (P < 0.001). Seven subjects (33%) had additional laser treatment to achieve IOP control. Six subjects who were therapy failures included three who developed no light perception in the setting of proliferative diabetic retinopathy, one subject with chronic angle-closure glaucoma who gradually developed no light perception after refusing further treatment or medication, and two subjects who developed retinal detachments. One child who was a qualified success underwent enucleation and debulking of an enlarging neurofibroma that caused significant proptosis and disfigurement. CONCLUSIONS: In cases of glaucoma that are uncontrolled despite a glaucoma aqueous tube shunt and multiple medications, adjunctive transscleral diode cyclophotocoagulation treatment(s) is a viable option to lower IOP.

Adult↗
PubMed1986

Hyperviscosity retinopathy secondary to polyclonal gammopathy in a patient with rheumatoid arthritis.

A patient with rheumatoid arthritis developed retinal venous stasis as part of a hyperviscosity syndrome secondary to a polyclonal gammopathy. Ocular findings included bilateral retinal venous dilation, disc hyperemia, optociliary venous collaterals, and left macular edema. This clinical picture improved following systemic corticosteroid therapy. Although occasional cases of rheumatoid polyclonal gammopathy causing hyperviscosity have been described in the rheumatology literature, this case represents the first detailed ophthalmological documentation of this occurrence.

Arthritis, Rheumatoid↗
PubMed1996

Prognostic factors for retinal vein occlusion: prospective study of 175 cases.

BACKGROUND: The prognosis of retinal vein occlusion is highly unpredictable because nonischemic types may convert into ischemic types within the first months. This study was designed to identify epidemiologic characteristics of the different types of retinal vein occlusion, their visual outcome, and their prognostic factors. METHODS: The authors analyzed prospectively the data from patients who have had retinal vein occlusion with complete medical and biologic examination, including fluorescein angiography, and a 1-year follow-up. RESULTS: One hundred seventy-five retinal vein occlusion eyes consisted of 120 central retinal vein occlusions (CRVO), 7 hemicentral occlusions, and 48 branch occlusions. In initially nonischemic CRVO eyes, retinal ischemia developed in 54%. The study of prognostic factors in the CRVO group showed that older age, male sex, and the number of risk factors (systemic vascular risk factors and glaucoma) were correlated with a poor visual outcome and with the development of retinal ischemia, as well as baseline visual acuity, initial extent of retinal ischemia, and rheologic findings (hematocrit, fibrinogen, and erythrocyte aggregation levels). Logistic regression underlined the prognostic role of sex, the number of risk factors, erythrocyte aggregation, and initial clinical features. Persistent macular edema was shown to be associated with hyperlipidemia and cardiovascular history, and inversely correlated to glaucoma. CONCLUSION: Because clinical characteristics of CRVO may worsen, the authors' results provide a basis to predict visual outcome by taking into account epidemiologic and rheologic findings. A careful follow-up of these patients is recommended.

Adult↗
PubMed2001

Developmental expression of DCC in the rat retina.

The protein product of the deleted in colorectal cancer (DCC) gene possesses netrin-binding activity and may be involved in axonal guidance during retinal development. The temporal and spatial expression of DCC was analyzed in developing rat retina by means of immunoblotting and immunohistochemistry as well as by reverse transcription-polymerase chain reaction. Transient DCC protein expression is evident on ganglion cell axons in embryonic and neonatal retina. Double labeling experiments demonstrate DCC immunolabeling on processes that stratify in the inner plexiform layer and are derived from cholinergic amacrine cells. This pattern is maintained during the early postnatal period. DCC immunolabeling in the inner plexiform layer declines with age and is not observed in adult retina. The down-regulation of the DCC protein is confirmed by Western blot analysis. mRNA for DCC is expressed in embryonic, postnatal and adult retina and shows no correlation with the protein down-regulation. We suggest that DCC expression may be correlated with the functional segregation of the inner plexiform layer.

Animals↗
PubMed2003

Transient muscarinic calcium mobilisation in transdifferentiating as in reaggregating embryonic chick retinae.

Two independent in vitro regeneration systems of the embryonic chick retina (E4-5) were used to study the mobilisation of intracellular calcium by the neurotransmitters acetylcholine (ACh) and glutamate, as measured by Fura-2 fluorescence changes. Retinal pigment epithelium (RPE) explants under the influence of basic fibroblast growth factor transdifferentiate into a retina-like tissue with normal laminar organisation, while rosetted spheres reaggregated from fully dispersed cells of the embryonic retina will achieve only an inferior tissue organisation, characterised by regions of an inverted retina [Layer et al., Neuroreport 12 (2001) A39-46]. ACh induced a pronounced Ca(2+) response in young explants, and a similar but less pronounced response in reaggregates; this response decreased almost entirely after 1 week in culture. In contrast, a Ca(2+) response to glutamate became detectable later, continuously increasing during this period. The response to ACh was strictly mediated by muscarinic ACh receptors (mAChRs), since it was inhibited by preincubation with atropine, but not tubocurarine; correspondingly, it was mimicked by muscarine, but not nicotine. Studies with mAChR blockers, preferentially acting on the m1-, m2-, or m3-receptor subtypes, suggested that the muscarine-induced Ca(2+) response is mediated by m1- and/or m3-type mAChRs, but not by the m2-type. These results show that (i) similar to the in vivo retina, in both a transdifferentiating and a reaggregating system an early muscarinic Ca(2+) response is active, which (ii) roughly parallels periods of cell proliferation, and (iii)-as evidenced by the reaggregates-does not depend on any tissue pre-organisation. In contrast, a response to glutamate becomes prominent only when tissue differentiation commences. This is the first demonstration of a physiological response in regenerating chick retinas, supporting their validity as models both of retinal development and regeneration.

Acetylcholine↗
PubMed1996

Hormonal and non-hormonal regulation of glutamine synthetase in the developing neural retina.

Two isoforms of the glucocorticoid receptor, with apparent molecular mass of 90 and 95 kDa, are expressed in embryonic chicken neural retina. The 95-kDa receptor represents a hyperphosphorylated form of the 90-kDa receptor. Activation of the glucocorticoid receptor by cortisol results in a dose-dependent increase in receptor phosphorylation, translocation of receptor molecules into the nucleus and a decline in the total amount of the receptor. Activation of the glucocorticoid receptor can also be observed in the developing retinal tissue in ovo. At late embryonic ages, when the systemic level of glucocorticoids increases, a substantial quantity of receptor molecules becomes translocated into the nucleus, the relative level of the 95-kDa isoform increases, and the total amount of receptor declines. Activation of the receptor molecules in ovo correlates directly with an increase in transcription of the glucocorticoid-inducible gene, glutamine synthetase. The close correlation between the increase in systemic glucocorticoids, activation of glucocorticoid receptor molecules and induction of glutamine synthetase gene transcription suggests that glucocorticoids are directly involved in the developmental control of glutamine synthetase expression. Long-term organ culturing of embryonic retinal tissue in the absence of hormone results in an increase in glutamine synthetase expression. This increase, which is only 5 to 10% of that observed in ovo, is not mediated by activated receptor molecules and represents a mechanism for non-hormonal regulation of glutamine synthetase.

Animals↗
PubMed1990

Ocular manifestations in Fukuyama type congenital muscular dystrophy.

We describe a child with Fukuyama type congenital muscular dystrophy (FCMD) who had several ocular manifestations since birth. These included high myopia, strabismus, nystagmus and optic atrophy of both eyes. Later he developed retinal detachment of both eyes. Our survey of 33 cases with FCMD revealed that high myopia and optic atrophy are common in FCMD. Retinal detachment was reported in two cases in addition to the present one and was considered to be of developmental origin. The association of congenital muscular dystrophy with brain changes and ocular anomalies were found in FCMD, muscle, eye and brain disease (MEB) and Walker-Warburg syndrome (WWS). Ocular manifestations in FCMD were, in general, less severe than those in WWS or MEB. Our study suggests that FCMD, MEB and WWS are developmental abnormalities with a continual spectrum of disease severity.

Adolescent↗
PubMed1990

Corneal-scleral melt in association with cataract surgery and intraocular lenses: a report of four cases.

Four patients with rheumatoid arthritis had cataract extraction with implantation of an intraocular lens (IOL). Postoperatively three patients developed progressive scleromalacia perforans. All three cases required patch grafting of the sclera and two of them developed progressive melting of the sclera and graft. The fourth case involved progressive corneal melting with extrusion of the IOL despite treatment with penetrating keratoplasties. All four cases developed retinal detachments with loss of vision and three of the eyes were subsequently enucleated. We describe each case and discuss the clinicopathologic correlations of this condition. The need for careful evaluation of rheumatoid arthritis patients with cataract surgery and IOL implantation is emphasized.

Aged↗
PubMed1996

Phacoemulsification with intraocular lens implantation in high myopia.

PURPOSE: To assess phacoemulsification and posterior chamber intraocular lens (IOL) implantation in highly myopic eyes and to compare the results of sutureless scleral tunnel incision and sutured scleral incision techniques. SETTING: The Eye Institute of Utah, Salt Lake City. METHODS: A series of 109 highly myopic eyes (axial length over 26.00 mm) were reviewed at a mean postoperative follow-up of 27 months. RESULTS: Postoperative corrected visual acuity was 20/40 or better in 94% of eyes, and uncorrected visual acuity was 20/40 or better in 77% of eyes. Posterior capsule opacification developed in 50% of eyes; 95% of these had neodymium:YAG (Nd:YAG) laser capsulotomy. Cystoid macular edema occurred in two eyes, and one eye developed retinal detachment following Nd:YAG capsulotomy. Eyes that had sutureless scleral tunnel incisions attained earlier postoperative rehabilitation of visual acuity and stabilization of astigmatism than did patients who had sutured scleral incisions. CONCLUSIONS: The results of this study of highly myopic eyes indicate that treating retinal pathology preoperatively and using the sutureless procedure, phacoemulsification, and in-the-bag IOL placement lead to good visual outcome, a lower rate of retinal complications, and a more stable wound.

Adult↗
PubMed1999

Lbx2, a novel murine homeobox gene related to the Drosophila ladybird genes is expressed in the developing urogenital system, eye and brain.

We describe the cloning, expression pattern, and genomic organization of Lbx2, a murine homologue of the Drosophila and mammalian ladybird genes. Lbx2 includes a homeodomain motif most closely related to those of Lbx1 and the Drosophila ladybird proteins. Lbx2 transcripts are first detected at E10.5 when they are located in the gonadal component of the urogenital ridge. Expression of Lbx2 dramatically increases by E11.5 in the urogenital ridges, and in the cranial surface ectoderm. At later stages, Lbx2 transcripts are expressed in the brain and organs derived from the urogenital ridge, including the gonadal tubercle, kidneys, and adrenal glands. From E14.5 to birth, Lbx2 expression is evident in the developing retinal neuroepithelium and the vibrissa.

Amino Acid Sequence↗