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.

SourceResearch connectionFrom yearThrough year

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

At least 1,225 records · Page 68Linked to original sources

PubMed1995

Expression, secretion, and age-related downregulation of pigment epithelium-derived factor, a serpin with neurotrophic activity.

Retinal pigment epithelial (RPE) cells form a functional complex with photoreceptor neurons of the retina, interacting through the interphotoreceptor matrix (IPM). We now provide evidence that the gene for pigment epithelium-derived factor (PEDF), a protein possessing neurotrophic and neuronal-survival activities, is highly expressed by both fetal and young adult RPE cells. PEDF mRNA is present in RPE cells of the human eye at 17 weeks of gestation, demonstrating its potential for action in vivo during early retinal development. The PEDF protein is secreted in vivo where it constitutes a part of the fetal and adult IPM surrounding photoreceptor outer segments. A polyclonal PEDF antibody recognizes at least four isoforms of secreted human and bovine PEDF by two dimensional gel analysis, and detects a similar 50 kDa protein in the IPM of several other vertebrate species. Within soluble extracts of RPE cells, however, where little, if any, of the 50 kDa species can be detected, an immunoreactive 36 kDa protein is observed by Western blot analysis. By immunofluorescence, PEDF is localized intracellularly in association with the nucleus, presumptive secretory granules, and cytoskeletal elements of cultured RPE cells with PEDF and actin antibodies colocalizing to the same cytoskeletal structures. During initial stages of attachment, PEDF and actin also concentrate at the tips of pseudopods extended by the cultured RPE cells. However, with successive passages, synthesis, and secretion of the PEDF protein as well as transcription of its mRNA decrease and are lost by about 10 passages. In parallel, cultured RPE cells lose their proliferative potential and change from an epithelial-like morphology in early passages to a more fibroblast-like appearance by about the 10th passage. PEDF is thus apparently present intracellularly and extracellularly in both fetal and early adult periods where it could be involved in cellular differentiation and survival and with its loss, in the onset of senescence.

Aging↗

PubMed1994

Neurogenesis in the vertebrate retina.

Many studies concerned with the control of neurogenesis in the retina, as well as other parts of the nervous system, impose the dichotomy of lineage restrictions versus environmental regulation on the design and interpretation of experiments. Recent work on retinal development has focused primarily on "environmental regulation," and this article will review some observations from these studies that provide clues about signals and mechanisms that control proliferation and cell type determination in the retina. Although still at an early stage, these studies already indicate that regulatory signals are not easily categorized as affecting only proliferation or differentiation, but are instead pleiotropic. Interpretation of these findings will be considered in terms of recent work in other systems, which further demonstrates that signals and regulatory mechanisms cannot be classified so simplistically and which suggests that polarizing regulatory mechanisms in terms of lineage restrictions and environmental regulation underestimates the interplay between these types of mechanisms.

Aging↗

PubMedDate not supplied

Retinopathy of prematurity: diagnosis and management [continuing education credit].

1. Despite advancements in neonatal and ophthalmic care, over 500 infants per year are blinded by retinopathy of prematurity (ROP). 2. Cryotherapy and laser photocoagulation have greatly improved the prognosis for infants with ROP. 3. Despite timely intervention, some infants with ROP will develop retinal detachment.

Cryotherapy↗

PubMedDate not supplied

[The early changes in the fundus oculi of premature infants].

The authors prospect the fundus at 69 prematures with birth weight under 1,500 g and at 49 prematures with birth weight over 1,600 g, whose neonatal pathology required intermittent administration of oxygen. The examination were done at the medium age of 5.5-6.9 weeks, when the retinal development is completed. The results show a greater proportion of the nervous systems lesions and of the retinopathy at the prematures with birth weight less than 1,500 g, in similar conditions of oxygen administration and prophylaxis with E-vitamin. It is indicated the opportunity of fundus investigation at all the prematures with very low birth weight and the necessity of prophylactic administration of E-vitamin starting from the first day of life.

Ascorbic Acid↗

PubMed1996

Trilateral tumors in four different lines of transgenic mice expressing SV40 T-antigen.

PURPOSE: A line of transgenic mice containing the simian virus (SV) 40 T-antigen (T-ag) gene driven by the beta-luteinizing hormone (BLH) promoter developed bilateral retinoblastoma and primitive neuroectodermal tumors (PNET) of the midbrain. Midbrain tumors arose from the subependymal layer of the cerebral aqueduct. Bilateral ocular and brain tumors ("trilateral") were found in three other SV40 T-ag transgenic murine lines containing different promoters (murine interphotoreceptor retinoid-binding protein (IRBP), human IRBP, and alpha A-crystallin). To gain insight into the regulatory mechanisms involved in central nervous system tumorigenesis, the authors examined brain tumors from four lines of SV40 T-ag mice with different promoters. METHODS: Formalin-fixed brain tumors were examined from four lines of transgenic mice containing different promoters linked to the protein coding region of the enhancerless SV40 T-ag oncogene. Transgenes contained the following promoters: BLH, mouse 1.8-kb IRBP, human 1.3-kb IRBP, and alpha A-crystallin. RESULTS: Mice with a 1.8-kb IRBP promoter develop retinal photoreceptor and pineal tumors. Intracranial tumors arising from the subependymal layer of the third ventricle also were observed. Mice with a 1.3-kb IRBP promoter exhibit bilateral retinal PNET and PNET originating from the subependymal layer of the third ventricle. Mice with the alpha A-crystallin promoter exhibit bilateral lens tumors and PNET of the midbrain. CONCLUSIONS: Ocular tumors in these mice may be ascribed to the promoter-driven, tissue-specific expression of SV40 T-ag. The common finding of PNET arising from the subependymal layer of the diencephalon is unlikely to be promoter related. These findings indicate that a regulatory region specific to the subependymal layer of the cerebral aqueduct and third ventricle resides in the structural region of the SV40 T-ag gene.

Animals↗

PubMed1996

Genetic aspects of uveal melanoma: a brief review.

Uveal melanoma usually occurs sporadically in the absence of obvious genetic predisposing factors. However, in rare patients, there is a suggestion that there may be genetic predisposition. Rare occurrences of familial uveal melanoma are believed to be inherited in an autosomal dominant mode. There are a few clinical conditions that can predispose to or be associated with uveal melanoma, including ocular melanocytosis, neurofibromatosis type I, and familial atypical mole and melanoma syndrome. Nonrandom cytogenetic changes in uveal melanoma are characterized by monosomy 3, trisomy 8, and structural or numerical abnormalities of chromosome 6. Alterations of chromosome 9p are less frequently observed. CDKN2 gene, a cutaneous melanoma predisposition gene, is probably not a uveal melanoma predisposition gene as evidenced by the lack of somatic mutations involving this gene in uveal melanoma samples and the absence of germline mutations in familial uveal melanoma patients. Transgenic mouse models developed using a tyrosinase promoter tagged with a mutated ras gene or SV40-Tag oncoprotein develop retinal pigment epithelium tumors that resemble uveal melanoma. We propose that uveal melanoma cases be categorized on genetic basis according to a new classification system. This classification scheme will help to identify and uniformly categorize uveal melanoma patients with genetic predisposition. Such patients offer unique opportunities for studying the genetic aspects of uveal melanoma and, therefore, appropriate tissue samples should be obtained from them for molecular genetic studies. Further studies are needed to fully understand the genetic aspects of uveal melanoma.

Animals↗

PubMed1997

[Ocular complications of atopic dermatitis].

We examined the frequency and types of ocular complications that developed in 560 eyes of 280 patients with atopic dermatitis at the Department of Dermatology, Tokyo Medical College Hospital. Mild ocular involvement included blepharitis in 294 eyes (52.5%), conjunctivitis in 221 eyes (39.5%), and superficial punctate keratopathy in 65 eyes (11.6%). More serious ocular complications leading to decreased visual function occurred in 133 eyes (23.8%) that developed lens opacities, and 34 eyes (6.0%) that developed retinal break or retinal detachment. Because of the presence of abnormalities in the peripheral retina, we believe that a pathogenic factor may have been present in the vitreous of these atopic dermatitis patients. Many of our patients with atopic dermatitis had serious ocular complications in the absence of ocular symptoms. Thus it is important to conduct a thorough ophthalmological examination in the early period of disease in atopic dermatitis patients, both for the management of early but serious ocular complications, as well as for the preservation of visual function.

Adolescent↗

PubMed1996

Fish and healthy pregnancy: more than just a red herring!

In modern Western diets we eat predominantly omega-6 essential fatty acids from vegetable oils, and too little omega-3. The Department of Health recommends doubling the amount of omega-3s we eat. Omega-3 essential fatty acids (EFAs) are derived mainly from fish oils. Omega-3s are believed to help reduce the risks of cardiovascular disease. Among the main materials required for fetal brain and CNS growth in late pregnancy are omega-3s (mainly docosahexaenoic acid [DHA]) and omega-6 EFAs (mainly arachidonic acid [AA]). These come from the mother's diet. Several formulae for preterm infants now contain DHA and AA to aid optimum brain, nerve and retinal development. One manufacturer has begun to include DHA and AA in formulae for term babies. Breast milk contains DHA and AA, derived from the mother's diet. Eating oily fish in pregnancy has been found to have a slight beneficial effect on birthweight and length of gestation. Eating fresh or canned oil-rich fish (e.g. kippers, herring, mackerel, salmon, sardine, pilchards, tuna) twice or three times a week can be encouraged as part of a healthy balanced diet, in pregnancy and for all the family. As well as containing omega-3 polyunsaturates, oily fish is a good source of protein and vitamins A and D. Alternatively, a fish-oil supplement may be taken. Cod liver oil is best avoided during pregnancy, because of concerns over the possible teratogenicity of vitamin A.

Animals↗

PubMed1997

The mGluR6 5' upstream transgene sequence directs a cell-specific and developmentally regulated expression in retinal rod and ON-type cone bipolar cells.

We generated transgenic mice, using 9.5 kilobase pairs of the 5' upstream sequence from the mouse metabotropic glutamate receptor subtype 6 (mGluR6) gene fused to the beta-galactosidase (lacZ) reporter gene, and investigated the promoter function of the cell-specific and developmentally regulated expression of mGluR6. Most of the independent transgenic lines commonly showed the lacZ expression in the defined cell layers of the retina, and four transgenic lines were characterized in detail for cell-specific lacZ expression patterns by X-gal staining and lacZ immunostaining. The lacZ-expressing retinal cells were classified into two cell types. One cell type was identified as rod bipolar cells on the basis of colocalization of protein kinase C (PKC) immunoreactivity and morphological criteria. The other cell type was PKC-immunonegative and resided at the cell layers corresponding precisely to ON-type cone bipolar cells. The latter bipolar cells were found to exist as a large cell population comparable to rod bipolar cells. This observation was confirmed by coimmunostaining of dissociated retinal cells with the lacZ and PKC antibodies. The ontogeny analysis indicated that the lacZ expression completely agrees with a temporal expression pattern of mGluR6 during retinal development. This study demonstrates that the mGluR6 5' upstream genomic sequence is capable of directing a cell-specific and developmentally regulated expression of mGluR6 in ON-type bipolar cells and supports the view that mGluR6 is responsible for ON responses in both the rod and cone systems.

Animals↗

PubMed1997

[Description of the prismation method in the rehabilitation of low visions of macular origin].

GOALS: This work aimed at presenting an original rehabilitation method based on the prismation available for patients with organic lesions of the macula. We report results obtained in our first series of patients. MATERIAL AND METHODS: The treatment was given to 14 patients, 7 women and 7 men, aged from 68 to 92 years, with an average age of 81.64, followed in "Low Vision" consultation, and suffering from bilateral macular diseases. All the patients with age-related macular degeneration developed retinal correspondences. They all received a bilateral prismation over their old correction. The orientation of the prisms taking into account the eccentric fixations. The criteria chosen for surveillance were binocular subjective and objective acuity, contrast sensitivity and vision of colours. RESULTS: For all the patients concerned, the method led to an immediate subjective improvement of the visual function. Tolerance to optical support was improved. The patients recovered better self-sufficiency in their daily life. The objective binocular for VA was improved by at least one line for 92.86% of the patients, by at least 2 lines for 42.85% and by 3 lines for 7.14%. The binocular contrast sensitivity was better for all the patients. Regarding the vision of binocular colours, the examination performance time was improved for all the patients. CONCLUSIONS: Prismation allows optimal use of the corresponding eccentric fixation areas. It appears as an interesting new therapeutic method for patients with macular-related low vision. It is complementary to rehabilitation treatment of such patients.

Aged↗

PubMed1996

Transsclerally sutured versus ciliary sulcus lenses.

We evaluated retrospectively the results of 39 eyes in which the implantation of a lens in the capsular bag was not possible. Due to the loss of capsule a transsclerally sulcus sutured lens (TSSL) was implanted in 9 eyes. In 30 eyes a ciliary sulcus supported lens (SSL) could be implanted using residual capsule support. Lens implantation in the ciliary sulcus resulted in improved vision in 33/39 eyes (7/9 TSSLs, 26/30 SSLs). Postoperatively slight decentration of the implant lens was observed in 3 eyes, 6 eyes developed glaucoma, 5 eyes developed hyphema after surgery and 2 patients developed retinal detachment in the late postoperative period.

Adult↗

PubMed1998

The use of the consensual light reflex as an aid to performing laser peripheral iridectomy in patients with pigment dispersion syndrome and pigmentary glaucoma.

PURPOSE: The authors explore an alternative method of performing laser peripheral iridectomy (LPI) in patients with pigment dispersion syndrome and pigmentary glaucoma (PDS/PG) who are high myopes and therefore at increased risk of developing retinal detachment. METHODS: Four myopic patients with PDS/PG had LPI performed in one eye. A transilluminator was held up to the opposite eye to provide pupillary constriction via the consensual light reflex. No miotics were used. RESULTS: All LPIs were easily performed without complications. CONCLUSION: The authors present an alternative method to the standard use of pilocarpine for LPI theoretically to decrease further the incidence of retinal detachment in populations predisposed to it.

Accommodation, Ocular↗

PubMed1998

Transforming growth factor-beta1 induces apoptotic cell death in cultured retinal endothelial cells but not pericytes: association with decreased expression of p21waf1/cip1.

Transforming growth factor-beta1 (TGF-beta1) regulates a variety of cellular functions. In several types of cells, for example, it acts as a growth inhibitor and an inducer of apoptotic cell death. Although one of the important modulators in retinal vascular development and retinal neovascularization, the effects of TGF-beta1 on retinal microvascular cells are not fully defined. We have found that proliferation of both bovine retinal endothelial cells (EC) and pericytes was inhibited by TGF-beta1 in a concentration-dependent manner. However, only retinal EC lost viability after exposure to increasing concentrations of TGF-beta1 (up to 10 microg/ml) in the presence of 2% fetal bovine serum. Dying EC exhibited the morphological and biochemical characteristics of apoptosis. Fragmented nuclei and chromatin condensation were apparent after staining with the fluorochrome Hoechst 33258 and the reagent ApopTag; moreover, gel electrophoresis of DNA from TGF-beta1-treated EC demonstrated degradation of chromatin into the discrete fragments typically associated with apoptosis. The addition of anti-TGF-beta1 neutralizing antibody abolished the apoptotic cell death induced by TGF-beta1. Because not all the EC in a given culture died after exposure to TGF-beta1, we separated the apoptosis-sensitive cells from those resistant to TGF-beta1 -mediated apoptosis and determined the expression of several proteins associated with this apoptotic pathway. Apoptosis of EC mediated by TGF-beta1 was associated with a decreased level of the cyclin-dependent kinase inhibitor p21waf1/cip1, compared with that observed in the apoptosis-resistant cells. In contrast, the translation product of the tumor-suppressor gene p53 was increased in the TGF-beta1-treated apoptotic cells. Thus, we propose that p21waf1/cip1 and p53 function in distinct pathways that are protective or permissive, respectively, for the apoptotic signals mediated by TGF-beta1.

Animals↗

PubMed1999

A novel pineal night-specific ATPase encoded by the Wilson disease gene.

We have identified a pineal night-specific ATPase (PINA), a novel splice variant of the ATP7B gene disrupted in Wilson disease (WD). PINA expression exhibits a dramatic diurnal rhythm in both pineal gland and retina with 100-fold greater expression at night than at day. PINA is expressed in pinealocytes and a subset of photoreceptors in adult rats and is transiently expressed in the retinal pigment epithelium and the ciliary body during retinal development. Nocturnal pineal expression of PINA is under the control of a suprachiasmatic nucleus clock mediated by superior cervical ganglion innervation of the pineal. In vitro, PINA expression in pineal cells can be stimulated by agents activating the cAMP signal transduction pathway. PINA is able to restore copper transport activity in Saccharomyces cerevisiae deficient in the homologous copper-transporting ATPase CCC2, suggesting that this protein may function as a copper transporter in rat pinealocytes. These studies suggest a potential role of rhythmic copper metabolism in pineal and/or retina circadian function.

Adenosine Triphosphatases↗

PubMed2001

Association between cytomegalovirus-specific reactivity of T cell subsets and development of cytomegalovirus retinitis in patients with acquired immunodeficiency syndrome.

The association between cytomegalovirus (CMV)-specific reactivity of T cell subsets and development of CMV retinitis (CMV-R) was prospectively studied in 50 CMV-seropositive AIDS patients. The frequency of CMV-specific CD69 expression on CD8 T cells was similar in patients with and patients without CMV-R (median, 1.0% vs. 1.2%; P=.14). However, the frequency of CMV-specific CD69 expression on CD4 T cells was significantly lower in patients with CMV-R than in those without CMV-R (median, 0.4% vs. 2.25%; P<.001). CMV-specific CD4 T cell reactivity in patients who developed CMV-R shortly after starting highly active antiretroviral therapy (HAART) remained low, although the CD4 cell counts increased markedly. Therefore, development of CMV-R is associated with a poor CMV-specific reactivity of CD4 T cells but not with poor reactivity of CD8 T cells. Development of CMV-R after initiation of HAART is associated with a poor reconstitution of CMV-specific immune response, rather than with immune rebound.

AIDS-Related Opportunistic Infections↗

PubMed1996

Changing patterns of spontaneous bursting activity of on and off retinal ganglion cells during development.

In adult ferrets, retinal ganglion cells (RGCs) responsive to increased (On) or decreased (Off) illumination convey information to different cellular layers of the dorsal lateral geniculate nucleus (dLGN). These dLGN sublaminae emerge during development when RGCs are found to undergo correlated spontaneous bursting activity. Using Ca2+ imaging and intracellular dye-filling techniques, we demonstrate here that in ferret neonates, morphologically identified On and Off beta RGCs have similar burst frequencies prior to the segregation of their inputs in the dLGN, but during the segregation period, they develop distinct burst frequencies. Although the bursts of On cells and Off cells occur synchronously, On cells burst only 25%-35% of the time that Off cells do. This change in the temporal bursting patterns of On and Off RGCs may underlie the segregation of their inputs on dLGN neurons.

Age Factors↗

PubMed1991

Early development of the retinal line of decussation in normal and albino ferrets.

This work describes the retinal origin of the crossed and uncrossed projections in newborn, 9-day-old and adult normally pigmented and albino ferrets. Horseradish peroxidase (HRP) was injected unilaterally into the thalamic and midbrain visual centers of ferrets to label retinal ganglion cells retrogradely. In normally pigmented adults, the retinal line of decussation was sharp and passed through the area centralis. Ganglion cells with uncrossed axons occupied the entire temporal retina. In albino adults, ganglion cells with uncrossed axons were distributed in the periphery of the temporal retina away from the area centralis. In the normally pigmented adults, about 11% of the retinal ganglion cells had uncrossed axons compared to about 4% in the albinos. At birth, normally pigmented ferrets had a sharp line of decussation with most (about 98%) uncrossed ganglion cells found in the temporal retina. In the newborn albinos, most uncrossed ganglion cells were in the temporal retina (about 89%), but there were many fewer than in the normal neonates and, as in the albino adults, the uncrossed ganglion cells were distributed along the temporal most margin of the retina. In the normal neonates, about 11% of the ganglion cells had uncrossed axons, compared to about 3% in the albino neonates. The area centralis and visual streak were not evident until 9 days after birth. From these results we conclude that the retinal line of decussation is essentially mature by birth in the ferret, and the degree of the albino's abnormality is as extreme in neonates as in adults. The retinal decussation is virtually mature at a stage of development when the crossed and uncrossed retinal afferent axons are completely intermingled in their target nuclei and prior to the onset of significant retinal ganglion cell loss.

3,3'-Diaminobenzidine↗

PubMed1999

Repetitive firing deficits and reduced sodium current density in retinal ganglion cells developing in the absence of BDNF.

Previous work by Cellerino et al. has shown that chronic absence of brain-derived neurotrophic factor (BDNF) resulted in hypomyelination of the optic nerve. Since myelination is influenced by neuronal activity, it is possible that a deficiency in BDNF during early development could alter the firing properties of retinal neurons. To test this hypothesis, patch-clamp recordings were performed in retinal whole mounts from BDNF-deficient (bdnf-/-), heterozygote (bdnf+/-) or wild-type control mice (bdnf+/+). Ganglion cell layer neurons (RGNs) were tested at different age [postnatal day (P)1-11] for their ability to encode graded depolarization with variable action potential frequency. At all developmental ages examined, RGNs exhibiting frequency coding were less frequently encountered in bdnf-/- than in bdnf+/+ mice. At P1, none of the RGNs from bdnf-/- mice displayed repetitive firing compared to 50% in bdnf+/+ mice, and by P7-11, only 50% of bdnf-/- RGNs exhibited repetitive firing compared to 100% in bdnf+/+ mice. Moreover, in bdnf-/- RGNs repetitive discharge was characterized by a reduced frequency increment per current change. Acquisition of repetitive firing was paralleled by a decrease in input resistance and a steep increase of sodium current density. In bdnf-/- mice, the onset of this increase occurred at later stages of development than in wild-type controls (bdnf-/-: P6-11; bdnf+/+: P2-6). The discharge pattern of P7-11 bdnf-/- RGNs resembled that of RGNs in neonatal wild-type mice and was mimicked by acute application of a Ca(2+) channel blocker. We conclude that BDNF plays an important role in the ontogeny of repetitive firing of RGNs.

Animals↗