• Biomolecules & Therapeutics
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• v.24 no.1
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• pp.94-98
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• 2016

The objective of the present study was to elucidate the effect of bisphosphonates, anti-osteoporosis agents, on glucose uptake in retinal capillary endothelial cells under normal and high glucose conditions. The change of glucose uptake by pre-treatment of bisphosphonates at the inner blood-retinal barrier (iBRB) was determined by measuring cellular uptake of $[^3H]3$-O-methyl glucose (3-OMG) using a conditionally immortalized rat retinal capillary endothelial cell line (TR-iBRB cells) under normal and high glucose conditions. $[^3H]3$-OMG uptake was inhibited by simultaneous treatment of unlabeled D-glucose and 3-OMG as well as glucose transport inhibitor, cytochalasin B. On the other hand, simultaneous treatment of alendronate or pamidronate had no significant inhibitory effect on $[^3H]3$-OMG uptake by TR-iBRB cells. Under high glucose condition of TR-iBRB cells, $[^3H]3$-OMG uptake was increased at 48 h. However, $[^3H]3$-OMG uptake was decreased significantly by pre-treatment of alendronate or pamidronate compared with the values for normal and high glucose conditions. Moreover, geranylgeraniol (GGOH), a mevalonate pathway intermediate, increased the uptake of $[^3H]3$-OMG reduced by bisphosphonates pre-treatment. But, pre-treatment of histamine did not show significant inhibition of $[^3H]3$-OMG uptake. The glucose uptake may be down regulated by inhibiting the mevalonate pathway with pre-treatment of bisphosphonates in TR-iBRB cells at high glucose condition.

• Applied Microscopy
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• v.37 no.3
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• pp.175-183
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• 2007

The Drosophila retinal cell is widely used to study cell development and cell signaling processes. In the past decades, conventional chemical fixation had been used to study the structure of retinal cells in Droscphila. Rapid freezing methods are superior to chemical fixation methods due to their fixation speed. Some Drosophila tissues, such as the eyes, should not be freezed due to their surrounding cuticle layer. Therefore, in the case of the Drosophila retina, the benefits of high pressure freezing and freeze substitution (HPF-FS) had not been verified. In this study, a retinal cell from Drosophila melanogaster had been studied by using the HPF-FS method. Compared to chemical fixation, the preservation of the cytoplasm in the HPF-FS sample was improved on the whole. The HPF-FS cell membranes were smoother than that of chemical fixation. In addition, HPF-FS preserved the mitochondria structures very well. These results of the present study suggest that HPF-FS is superior to other fixation methods for the preservation of the retinal cell structure.

• Biomolecules & Therapeutics
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• v.17 no.2
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• pp.175-180
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• 2009

Taurine is the most abundant free amino acid in the retina and transported into retina via taurine transporter (TauT) at the inner blood-retinal barrier (iBRB). In the present study, we investigated whether the taurine transport at the iBRB is regulated by oxidative stress or disease-like state in a conditionally immortalized rat retinal capillary endothelial cell line (TR-iBRB) used as an in vitro model of iBRB. First, [$^3H$]taurine uptake and efflux by TR-iBRB were regulated in the presence of extracellular $Ca^{2+}$. [$^3H$]Taurine uptake was inhibited and efflux was enhanced under $Ca^{2+}$ free condition in the cells. In addition, oxidative stress inducing agents such as tumor necrosis factor-$\alpha$ (TNF-$\alpha$), lipopolysaccharide (LPS), diethyl maleate (DEM) and glutamate increased [$^3H$]taurine uptake and decreased [$^3H$]taurine efflux in TR-iBRB cells. Whereas, 3-morpholinosydnonimine (SIN-1), which is known to NO donor decreased [$^3H$]taurine uptake. Lastly, TR-iBRB cells exposed to high glucose (25 mM) medium and the [$^3H$]taurine uptake was reduced about 20% at the condition. Also, [$^3H$]taurine uptake was decreased by cytochalasin B, which is known to glucose transport inhibitor. In conclusion, taurine transport in TR-iBRB cells is regulated diversely at extracellular $Ca^{2+}$, oxidative stress and hyperglycemic condition. It suggested that taurine would play a role as a retinal protector in diverse disease states.

• Biomolecules & Therapeutics
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• v.30 no.3
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• pp.291-297
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• 2022

Dry age-related macular degeneration (AMD) is a type of progressive blindness that is primarily due to dysfunction and the loss of retinal pigment epithelium (RPE). The accumulation of N-retinylidene-N-retinylethanolamine (A2E), a by-product of the visual cycle, causes RPE and photoreceptor degeneration that impairs vision. Genes associated with dry AMD have been identified using a blue light model of A2E accumulation in the retinal pigment epithelium and transcriptomic studies of retinal tissue from patients with AMD. However, dry macular degeneration progresses slowly, and current approaches cannot reveal changes in gene transcription according to stages of AMD progression. Thus, they are limited in terms of identifying genes responsible for pathogenesis. Here, we created a model of long-term exposure to identify temporally-dependent changes in gene expression induced in human retinal pigment epithelial cells (ARPE-19) exposed to blue light and a non-cytotoxic dose of A2E for 120 days. We identified stage-specific genes at 40, 100, and 120 days, respectively. The expression of genes corresponding to epithelial-mesenchymal transition (EMT) during the early stage, glycolysis and angiogenesis during the middle stage, and apoptosis and inflammation pathways during the late stage was significantly altered by A2E and blue light. Changes in the expression of genes at the late stages of the EMT were similar to those found in human eyes with late-stage AMD. Our results provide further insight into the pathogenesis of dry AMD induced by blue light and a novel model in vitro with which relevant genes can be identified in the future.

• Journal of Veterinary Clinics
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• v.24 no.2
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• pp.154-159
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• 2007

The objective of this retrospective study was to investigate the prevalence of retinal diseases in dogs presented to the Veterinary Medical Teaching Hospital, Seoul National University from April 2004 to December 2005. Sixty-five dogs (120 eyes) with retinal diseases involving blindness were included in this study. Age, breed, and gender data for all breeds were collected from medical records documenting vision loss. Generalized progressive retinal atrophy (gPRA) was the most common manifestation. Other prevalent findings included sudden acquired retinal degeneration (SARD) and retinal detachment (RD). Bilateral gPRA was found in 32 dogs with a female-to-male ratio of 1 : 1. The mean $age{\pm}SD$ of all dogs in this group was $4.66{\pm}2.30$ years with a range of 3 to 12 years. Breeds with highest prevalence of gPRA were Miniature Schnauzer (24/32, $mean{\pm}SD$ age: $3.79{\pm}0.78$ yr) and Poodle (2/32, $6.50{\pm}0.71$ yr). Twelve dogs (24 eyes) were diagnosed with SARD bilateraly, ranging from 3 to 13 years of age ($mean{\pm}SD:\;6.91{\pm}2.61$ yr). There were no abnormalities in fundus of 11 dogs at presentation. Electroretinography (ERG) without anesthesia was performed in 7 dogs, and all response was totally extinguished. Retinal detachment was identified in 21 dogs (32 eyes): 11 bilateral and 10 unilateral (7 right eye, 3 left eye). The most common breed was Shih Tzu (15/21, $mean{\pm}SD$ age: $4.39{\pm}3.24$ yr). Four other breeds comprised the remaining 6 cases (8 eyes). The everall mean age of the group was: $4.18{\pm}2.89$ years (range 0.8 to 14 years) with a female-to-male ratio of 1 : 1.1 (10 females, and 11 males).

• The Korean Journal of Zoology
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• v.1 no.2
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• pp.17-24
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• 1958

Since Kesser first described in 1934 the functional change of the autonomic nervous system caused by certain visible rays many researchers have unanimously approved that animals flashed with a red visible ray develop parasympathicotony while those flashed with a blue visible ray develop sympathicotony. On the other hand through studies made by our colleagues it is now well known that the inner-movement of the retinal pigments of frogs is stimulated in sympathicotony and is in reverse inhibited in parasimpathicotony. It is almost evident that the mechanism by which the inner-movement of the retinal pigments is due to sympathicotony derived from the excessive secretion of adrenalin. In addition , through may recent experiments on the pharmacological action of various medicines on the retinal pigments reaction of tadpoles , ranging from the excessive secretion of adrenalin. In addition , through my recent experiments on the pharmacologtical action of various medicines on the retinal pigments reaction of tadploes, raging from every developmental stage , Ifound that the movement of the retinal pigments by adrenalin is predominant in the earlier developmental stages of taopoles around 11 mm of body length, whereas other medicines fail to give any responce to the retinal pigments in such an earlier stage. When tadpoles grown to body length of 15-16m the retinal pigments move to the complete light position while kept in adrenalin solution. Based on these facts it might be well to consider that if tadpoles were grown under the visible rays for a given period, they might show a functional change of the autonomic nervous system and thereby cause of certain change in the physciological phases of the retinal reaction. Experiments were undertaken to find this matter and also to discover the simultaneous effects of the visible radiations on the developmental process of tadpoles. The results summarized as follows ; 1. The longest wave of visible rav has an effective reaction on the growth of body length of taopoles, while the shortest wave of visible ray causes the same for the metamorphoric differentiation of tadpoles. 2. When keeping two groups of tadpoles the first group of 15 mm body length grown for the period of one week and the latter group of 20 mm body length grown for two weeks under the various visible rays. swimming in adrenalin solution, the inner-movement of the retinal pigment occurs in both groups. The movement of pigments of the first group is accelerated in a sequence of blue ray \ulcorner green ray > brown ray> red ray, and that of the latter group is also accelerated in a sequence of blue ray>green ray > brown ray and red ray. 3. When keeping tow groups of tadpoles, the first group of 20 mm body length grown for the period of two weeks, the latter group of 25 m body length grown for three wheeks, under the various visible rays in sunlight, the inner-movement of the retinal pigments occurs in both groups. The movement of pigments of the first group is accelerated in a sequence of blue ray> green ray>brown ray and red ray, and that of the latter group is also accelerated in a sequence of blue ray > brow ray>red ray. 4. In order words, there facts manifest that tadpoles grown under the various visible rays reveal functional disturbances of the autonomic nervous system, at the time of 15 mm body length by adrenalin solution, which is a unique indicator illustrating the status of sympathicotony, and at the time of 20 mm body length by sunlight. This means that the longest visible ray cause sympathicotony, while the shortest visible ray causes parasympathicotony.

• Proceedings of the Korean Society of Medical Physics Conference
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• 2006.08a
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• pp.154-154
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• 2006

• 한국가시화정보학회:학술대회논문집
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• 2002.04a
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• pp.51-78
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• 2002

A number of research groups worldwide are studying electronic implants that can be mounted on retinal optic nerve/visual cortex to restore vision of patients suffering from retinal degeneration. The implants consist of a neural interface made of biocompatible materials, one or more integrated circuits for stimuli generation, a camera, an image processor, and a telemetric channel. The realization of these classes of neural prosthetic devices is largely due to the explosive development of micro- and nano-electronics technologies in the late $20^{th}$ century and biotechnologies more recently. Animal experiments showed promise and some human experiments are in progress to indicate that recognition of images can be obtained and improved over time. We, at NBS-ERC of SNU, have started our own retinal implant project in 2000. We have selected polyimide as the biomaterial for an epi-retinal stimulator. In-vitro and in-vivo biocompatibility studies have been performed on the electrode arrays. We have obtained good affinity to retinal pigment epithelial cells and no harmful effect. The implant also showed very good stability and safety in rabbit eye for 12 weeks. We have also demonstrated that through proper stimulation of inner retina, meaning vision can be obtained.

• Journal of Korean Ophthalmic Optics Society
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• v.19 no.1
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• pp.93-98
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• 2014

Purpose: We were aim to investigate individual difference of visual acuity (VA) decrease and the change of contrast threshold (CT) according to the level of optically induced retinal defocus. Methods: A total of 69 eyes were examined using consist of ten-graded decimal vision chart (Landolt's ring). After conducted full correction of subject's refractive error, a monocular VA and CT were measured according to sequential increase by 0.25 D each time. Results: VA gradually decreased according to the increase of retinal defocus level. Individual difference of VA decrease was range from 1.2 to 0.6 in retinal defocus induced by +0.25 D. When retinal defocus was induced as much as +0.50 D and +0.75 D, it was in the range of 1.0 to 0.3 and 0.9 to 0.1 respectively. With +1.00 D, some participants didn't even recognize the 0.1 in the chart. With +1.75 D, whole participant did not recognize the 0.1. Also, CT was gradually decreased with increase of the retinal defocus level. Conclusions: Examiners should consider individual difference in the decrease of VA according to the level of residual refractive error when determining final prescription of a patient.

• Journal of The Korean Ophthalmological Society
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• v.59 no.12
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• pp.1160-1165
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• 2018

Purpose: To evaluate the availability of ultra-wide field fundus photography based on eye steering technique to diagnose retinal breaks in patients with symptomatic posterior vitreous detachment (PVD). Methods: The medical records of patients with symptomatic PVD were reviewed. Retinal breaks were independently identified using four eye steering capture images of ultra-wide field fundus photographs. The sensitivity and specificity of eye steering capture imaging for diagnosing retinal breaks were calculated. Results: A total of 94 eyes of 94 patients were included. Using fundus examination after pupil dilatation, retinal breaks were diagnosed in 42 (45%) eyes. The sensitivity of the eye steering capture imaging was 98% (95% confidence interval [CI]: 88-100%), and the specificity was 98% (95% CI: 90-100%). Of the 58 retinal tears, 28 (97%) involving the superior quadrant, 10 (100%) involving the inferior quadrant, 6 (100%) involving the nasal quadrant, and 13 (100%) involving the temporal quadrant were identified using eye steering capture images. Conclusions: Ultra-wide field fundus photography based on eye steering technique was useful for diagnosing retinal breaks in patients with symptomatic PVD. However, eye steering photography could not adequately replace the fundus examination after pupil dilatation in all cases.