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Analysis of the IRBP gene as a cause of RP in 45 ARRP Spanish families. Autosomal recessive retinitis pigmentosa. Interstitial retinol binding protein. Spanish Multicentric and Multidisciplinary Group for Research into Retinitis Pigmentosa.

Autosomal recessive retinitis pigmentosa (ARRP) is a degenerative disorder of photoreceptors. Mutations in several genes encoding different proteins of the visual cascade are described. The inheritance of two intragenic markers within the interstitial retinol binding protein (IRBP) gene was established in 45 Spanish families with a history of ARRP. Homozygosity mapping and cosegregation analyses were positive in 19 families. Only one heterozygous T-C transition at position 3024 (exon 1) was detected in one consanguineous family. This variant was identified as a rare polymorphism and was present in 5% of the chromosomes analyzed.

Chromosome Segregation↗

Retinal twin cones or retinal double cones in fish: misnomer or different morphological forms?

Scanning retinal electronmicroscopy studies demonstrated the presence of both twin cones (two identical cones adhered together) and double cones (two non-identical cones adhered together) in the retinae of the major forms of fish, which included actinopterygi, elasmobranch, and teleosts. The complexity of these visual cells in the retinae of different groups of fishes was revealed for the first time and reflected on the diversities of functions of the fish retina in general.

Animals↗

Penetrating diathermy for retinal microincarceration in the management of giant retinal tears with inverted flaps.

Using vitrectomy, fluid-air exchange, penetrating diathermy, and scleral buckling, surgical success was achieved in 24 of 27 eyes with inverted giant retinal tears (GRTs) and concomitant unfavorable conditions. The follow-up period ranged from 6-52 months. Anatomic success was achieved in 18 eyes. Tears larger than 300 degrees with immobile flaps or advanced proliferative vitreoretinopathy (PVR) contributed significantly to surgical failure (P less than .05). Preoperative (greater than C2) and postoperative PVR figured significantly in unimproved final visual acuity (P less than .05). Penetrating diathermy was effective in fixating the repositioned retina, with little complication. Postoperative therapy with fluid-gas or air exchange or photocoagulation greatly enhanced final success.

Adolescent↗

Tumor-associated retinal pigment epithelial proliferation simulating retinal pigment epithelial tear.

A lesion with both the clinical and fluorescein angiographic appearance of the classical retinal pigment epithelial (RPE) tear was discovered over the dome of an actively growing metastatic choroidal tumor in a patient with a previous history of breast carcinoma. However, our patient exhibited no evidence of pigment epithelial detachment or age-related macular degeneration, the underlying cause of the RPE tear. Although we cannot be sure that a true RPE tear did not exist over our patient's tumor, more likely, we are observing a tumor induced zone of RPE dehiscence accompanied by RPE proliferation at its border, giving a very similar fundus appearance. Possible pathogenic mechanisms for the finding in our patient, and a comparison to those mechanisms responsible for the classical RPE tear, are discussed.

Bone Neoplasms↗

Morphogenesis of the retinal pigment epithelium: toward understanding retinal degenerative diseases.

The phenotype of an epithelial cell is defined by a unique combination of morphology, gene and protein expression, and protein localization. Results indicate that the terminal differentiation of the RPE cell can be described in part by changes in the polarity of its surface proteins alpha v beta 5 integrin, Na,K-ATPase, N-CAM, and EMMPRIN. Changes in protein/gene expression and protein localization in late stages of RPE development identify alpha v beta 5 integrin as a key player in RPE phagocytosis, and N-CAM and EMMPRIN as potentially important molecules in other RPE functions necessary for photoreceptor survival. By studying the trafficking of the later two proteins it is shown that entry into an apical or basolateral pathway in RPE cells cannot be predicted by the distribution of a given protein in other epithelial cells, and that this distribution may change through the course of RPE development. The mechanisms used by RPE and other epithelia to establish and maintain their specific polarity properties are fundamental to the formation and maintenance of their specific epithelial phenotype. The ability to therapeutically direct molecules incorporated into RPE by gene therapy into apical or basal surfaces requires an understanding of protein localization and expression. Furthermore, evidence is provided that assays capitalizing on changes in gene/protein expression and protein localization during the late stages of RPE development can prove a productive way of identifying proteins used by RPE for photoreceptor support. This approach can continue to be exploited to identify other proteins essential for the mission of the RPE cell, that may thus be likely candidates for participation in retinal degenerative disease.

Aging↗

Age and sex distribution of some retinal macular diseases: senile and presenile macular degeneration and central serous retinitis.

The age and sex distribution of senile macular degeneration (SMD) was investigated at the Low Vision Clinic in Stockholm. SMD increased with age and was found to be more common among women than men. This difference was not due to the fact that women live longer than men or related to women consulting ophthalmologists more often than men because of visual handicap. The age and sex distribution of presenile macular degeneration ( PSMD ) and central serous retinitis (CSR) was investigated at the Department of Ophthalmology of Falun Hospital. Also PSMD increased with age and was found to be more common among women than men, even if the sex difference was not as clear as for SMD. CSR was found to be more frequent at younger ages and, contrary to SMD and PSMD , more common among men. The reasons for these sex differences in frequencies of SMD, PSMD and CSR are not known.

Adult↗

Retinal ischemia (capillary nonperfusion) and retinal neovascularization in patients with diabetic retinopathy.

138 diabetic retinopathy patients with good fluorescein angiograms of the macular areas were studied. Areas of capillary nonperfusion (CNP) were surrounded by other capillary abnormalities and were often based on a larger retinal vessel. A satistically highly significant anatomical relationship was found between CNP and neovascularization. In addition, the frequency of neovascularization increased with the increase in size of CNP.

Diabetic Retinopathy↗

Retinal detachment during glaucoma therapy. Review. A case report of an occurrence of retinal detachment after using membranous pilocarpine delivery system [Pilokarpin lameller (Ocusert) 11 mg].

Miotic-induced retinal detachment (RD) is a condition that is not recognized as such by common consent. Clinically it has been shown that all miotic agents, whether strong or weak, can precipitate an RD, if there are additional contributing factors like high myopia, peripheral lattice degeneration of the retina, pathological vitreoretinal changes and previous history of an RD in the other eye, which all increase the basic risk of RD. Pilokarpin lameller 11 mg represents a form of miotic therapy having initially only a moderate accommodative and miotic effect, which further declines to a level of steady state during the next hours. Because the time interval after which a new Pilokarpin lameller unit is required lasts up to 1 week, the total amount of accommodation and miosis is much smaller than when applying daily 2% pilocarpine drops. However, it seems important, before the start of any kind of miotic therapy, to perform a careful examination and management of virtually all detachment-prone patients. This case report deals with an RD which occurred after 2 days of treatment with Pilokarpin lameller (Ocusert) 11 mg in a myopic patient who had a juvenile type of glaucoma and previous history of an RD in the other eye.

Adult↗

Occlusive thromboaortopathy (Takayasu's disease): cervical arterial stenoses, retinal arterial pressure, retinal microaneurysms and prognosis.

Eighty-one young Japanese patients with occlusive thromboaortopathy (Takayasu's disease) were classed into three groups according to the degree and extent of diameter stenosis in the 4 cervical arterial systems, as determined by serial aortography. Class I was made up of 63 patients with 70% or greater stenosis in less than 3 systems, including 33 patients without systemic hypertension (Class Ia). Class II was made up of 6 patients with 70% or greater stenosis in 3 systems and less than 50% stenosis in the remaining 1, including 5 patients without systemic hypertension (Class IIa). Class III was up of 12 patients with 70% or greater stenosis in 3 systems and 50% or greater stenosis in 1 system. Ophthalmodynamometric systolic pressure in patients in Class III was significantly lower than that in patients in Class IIa (p less than 0.001), but there was no significant difference between patients in Classes Ia and IIa. Microaneurysms and/or arteriovenous anastomoses in the retinal vessels were found in all but one patient in Class III and in only one patient in combined Classes I and II. These results indicate that each of the ophthalmodynamometric values and fundoscopic findings are very helpful in identifying the markedly severe occlusive lesions (Class III) of the 4 cervical arterial systems. In this chronic disease, however, angiography is most useful for evaluation of these severe lesions, to monitor progression from Classes I and II to Class III, in which the prognosis is rather poor.

Adult↗

Transcorneal electrical stimulation rescues axotomized retinal ganglion cells by activating endogenous retinal IGF-1 system.

PURPOSE: To investigate the effect of transcorneal electrical stimulation (TES) on the survival of axotomized RGCs and the mechanism underlying the TES-induced neuroprotection in vivo. METHODS: Adult male Wistar rats received TES after optic nerve (ON) transection. Seven days after the ON transection, the density of the surviving RGCs was determined, to evaluate the neuroprotective effect of TES. The levels of the mRNA and protein of insulin-like growth factor (IGF)-1 in the retina after TES were determined by RT-PCR and Northern and Western blot analyses. The localization of IGF-1 protein in the retina was examined by immunohistochemistry. RESULTS: TES after ON transection increased the survival of axotomized RGCs in vivo, and the degree of rescue depended on the strength of the electric charge. RT-PCR and Northern and Western blot analyses revealed a gradual upregulation of intrinsic IGF-1 in the retina after TES. Immunohistochemical analysis showed that IGF-1 immunoreactivity was localized initially in the endfeet of Muller cells and then diffused into the inner retina. CONCLUSIONS: TES can rescue the axotomized RGCs by increasing the level of IGF-1 production by Muller cells. These findings provide a new therapeutic approach to prevent or delay the degeneration of retinal neurons without the administration of exogenous neurotrophic factors.

Animals↗

Dimensional differences among the groups of retinal ganglion cells according to the retinal zones in chicks.

The populations of retinal ganglion cell (RGC) groups (Groups I, II, III, IV) were similar each other between the central and intermediate zones, but the population in the peripheral zone were clearly different from those in the central and intermediate zones due to increase of Group III and IV cells and decrease of Group I cells. The dimensions of somal area and dendritic field of Group I cells increased very gradually toward the peripheral zone, but those of other three Groups grew steeply in the peripheral zone. The correlation index between somal area and dendritic field of RGCs showed high coefficient in the central (r=0.73) and intermediate (r=0.77) zones, but lowered clearly in the peripheral zone (r=0.64) due to increase of Group III cells, which showed nonlinear relation between somal area and dendritic field.

Animals↗

Retinal noise, the performance of retinal ganglion cells, and visual sensitivity in the dark-adapted frog.

By extracellular recording of action potentials from single ganglion cells in the dark-adapted eyecup of the frog, we show that four different characteristics of a cell, the frequency-of-response function, the variability in responses to low suprathreshold stimulation, the maintained discharge, and the susceptibility to desensitization by weak background lights, all seem to reflect the same intrinsic noise. In a small fraction of reliable cells this noise is close to that expected from dark isomerizationlike events in rods, but it differs by orders of magnitude between cells. We have also determined a threshold intensity for the phototactic jumping behavior of frogs in darkness. This intensity, while below the human threshold, is still above the threshold for an appreciable fraction of frog retinal ganglion cells, and the sensitivity of this visually guided behavior at 16 degrees C is not strictly limited by dark events in rods.

Animals↗

[Mutation analysis of retinitis pigmentosa 1 gene in Chinese with retinitis pigmentosa].

OBJECTIVE: To investigate the frequency and pattern of RP1 point mutations in Chinese retinitis pigmentosa (RP) patients and to examine their effects on the development of RP. METHODS: Conformation sensitive gel electrophoresis (CSGE) and direct DNA sequencing were used to determine sequence alterations occurring in the entire coding region of the RP1 gene in 101 Chinese RP patients in Hong Kong. RESULTS: R677X was detected in one RP patient. A nonpathogenic nonsense mutation, R1933X, was identified in three normal individuals and one patient with Stargardt disease. The frequency of RP1 mutations among all RP patients in this study is 1/101. R677X is expected to lead to large disruptions of the encoded protein. Additionally, 10 more missense alterations in the RP1 gene were identified in the subjects of this study. Apart from M479I whose pathogenicity can not be determined currently, other sequence changes are just polymorphisms of the RP1 gene. CONCLUSION: The nonpathogenicity of R1933X indicates that the C-terminal 224 residues of RP1 protein may be not critical for RP1. Recently, a C-termnal truncating mutation, Y1053(1 bp del), was reported to occur in an RP patient. Thus RP can be caused by lack of the region of RP1 protein after codon 1052 but before 1933. To confirm such a proposition, a large genotyping study is necessary and is likely to reveal more RP causative mutations and uncover more sequence alterations different from those of other ethnic groups.

Adolescent↗

[Retinal and retinal pigment epithelium hamartoma].

Authors present four patients with combined hamartoma of the retina and retinal pigment epithelium who were observed for a period of 10 years. The significance of this entity lies primarily in its resemblance to malignant condition of the retina and choroid and in the vizual reduction. Clinical finding, diagnosis, natural history, histopathology, association with other diseases and therapy are discussed in this report as well.

Adult↗

Screening for mutations in a novel retinal-specific gene among Chinese patients with retinitis pigmentosa.

OBJECTIVE: To identify and evaluate mutations in the RP1 gene among Chinese patients with retinitis pigmentosa (RP). METHODS: Leukocyte DNA of 92 RP patients were collected in Hong Kong. Sequence changes of the entire coding region of the RP1 gene were examined using PCR, conformation sensitive gel electrophoresis and DNA sequencing. RESULTS: In total, 1 nonsense mutation and 1 nonsense variant as well as 10 missense alterations were identified in the RP1 gene, among which, Arg677Ter was found in 1 RP patient and another nonsense variant, Arg1933Ter, was identified in 3 normal individuals and 1 patient with Stargardt's disease, suggesting its nonpathogenicity. Arg77Ter is expected to lead to large disruptions of the encoded protein. CONCLUSIONS: The nonpathogenicity of Arg1933Ter indicates that the C-terminal 224 residues of RP1 protein may be not critical for RP1. The most C-terminal truncation previously reported was due to Tyr1053 (1-bp del) and occurred in RP patients. Thus RP can be caused by reduction in the level of the region of RP1 protein after codon 1052 but before 1933. To ascertain such a proposition, genotypes of more RP patients may reveal more RP causative mutations and more sequence alterations different than those of other ethnic groups.

Adolescent↗

[Evaluation of the macula which was not involved in retinal detachment after surgical treatment of retinal detachment using scleral indentation. Summary of a doctoral thesis].

The goal of the study was the evaluation of the influence of the nowadays most frequently used surgical methods in cases of retinal detachment on the macula not involved in the detachment. The study takes into account surgical interventions which have the same indications and principles of action. They are based on an extra-scleral indentation--temporary or permanent one--by means of a Lincoff-Kreissig balloon and a meridional silicone sponge implant. The examinations comprised 54 patients. They were divided into 2 groups: 1st group (24 patients) was treated by cryopexy and a Lincoff-Kreissig balloon, the 2nd group (30 patients) by cryopexy and a meridional silicone sponge implant. In all the patients of both groups the retina reattached. During the 5-years observation of patients of the 1st group no macular changes were detected; one did not observe metamorphopsia or disturbances of the color vision. In the 2nd group instead 17 patients claimed metamorphopsia, 20 patients showed disturbances of the color vision and angiography changes involving the macular region (13 patients).

Adult↗