• Journal of Yeungnam Medical Science
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• v.27 no.2
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• pp.91-97
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• 2010

Endothelial cells play a key role in pathological processes such as cancer cell metastasis, atherosclerosis, and diabetic retinopathy. Vascular smooth muscle cells directly involve in the formation of atheroma in atherosclerosis. Some kinds of the endothelial cells are simply harvested from the umbilical veins, the tunica intima of aortic walls, the retina using various enzymes solutions. Those purely isolated cells provide a powerful tool in vitro studies of the endothelial cell related diseases. In this context, the cultured smooth muscle cells after the isolation from the tunica media of aortic walls are also used for elucidating the pathogenesis of atherosclerosis. Here, I briefly introduce articles that include the isolation of human umbilical vein endothelial cells(HUVEC), aortic endothelial and smooth muscle cells, retinal microvascular endothelial cells(RMEC), as well as the diseases' applications of these cells.

• 제어로봇시스템학회:학술대회논문집
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• 2004.08a
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• pp.312-316
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• 2004

The paper presents a technique to identify the boundary of the optic disc in infant retinal digital images using an approach based on active contours (snakes). The technique can be used to be develop a automate system in order to help the ophthalmologist's diagnosis the retinopathy of prematurity (ROP) disease which may occurred on preterm infant,. The optic disc detection is one of the fundamental step which could help to create an automate diagnose system for the doctors we use a new kind of active contour (snake) method has been developed by Chenyang et. al. [1], based on a new type of external force field, called gradient vector flow, or GVF. GVF is computed as a diffusion of the gradient vectors of a gray-level or binary edge map derived from the image. The testing results on a set of infant retinal ROP images verify the effectiveness of the proposed methods. We show that GVF has a large capture range and it's able to move snakes into boundary concavities of optic disc and finally the optic disk boundary was determined.

• 제어로봇시스템학회:학술대회논문집
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• 2004.08a
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• pp.321-325
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• 2004

Retinopathy of Prematurity (ROP) is a common retinal neovascular disorder of premature infants. It can be characterized by inappropriate and disorganized vessel. This paper present a method for blood vessel detection on infant retinal images. The algorithm is designed to detect the retinal vessels. The proposed method applies a Lapalacian of Gaussian as a step-edge detector based on the second-order directional derivative to identify locations of the edge of vessels with zero crossings. The procedure allows parameters computation in a fixed number of operations independent of kernel size. This method is composed of four steps : grayscale conversion, edge detection based on LOG, noise removal by adaptive Wiener filter & median filter, and Otsu's global thresholding. The algorithm has been tested on twenty infant retinal images. In cooperation with the Digital Imaging Research Centre, Kingston University, London and Department of Opthalmology, Imperial College London who supplied all the images used in this project. The algorithm has done well to detect small thin vessels, which are of interest in clinical practice.

• The Korean Journal of Physiology and Pharmacology
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• v.18 no.1
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• pp.1-14
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• 2014

During long standing hyperglycaemic state in diabetes mellitus, glucose forms covalent adducts with the plasma proteins through a non-enzymatic process known as glycation. Protein glycation and formation of advanced glycation end products (AGEs) play an important role in the pathogenesis of diabetic complications like retinopathy, nephropathy, neuropathy, cardiomyopathy along with some other diseases such as rheumatoid arthritis, osteoporosis and aging. Glycation of proteins interferes with their normal functions by disrupting molecular conformation, altering enzymatic activity, and interfering with receptor functioning. AGEs form intra- and extracellular cross linking not only with proteins, but with some other endogenous key molecules including lipids and nucleic acids to contribute in the development of diabetic complications. Recent studies suggest that AGEs interact with plasma membrane localized receptors for AGEs (RAGE) to alter intracellular signaling, gene expression, release of pro-inflammatory molecules and free radicals. The present review discusses the glycation of plasma proteins such as albumin, fibrinogen, globulins and collagen to form different types of AGEs. Furthermore, the role of AGEs in the pathogenesis of diabetic complications including retinopathy, cataract, neuropathy, nephropathy and cardiomyopathy is also discussed.

• Journal of Yeungnam Medical Science
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• v.23 no.2
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• pp.227-231
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• 2006

The Valsalva maneuver is described as an expiratory effort against a closed glottis or airway. It leads to elevation of retinal venous pressure and may result in retinal hemorrhage. A fifty two- year-old man presented with an acute reduction of central visual acuity in his right eye which occurred after considerable straining at stool. Detailed past medical history revealed that he suffered from chronic constipation and hypertension. There were one disc sized subhyaloid hemorrhage and three small intraretinal hemorrhages around the fovea at the dilated fundus examination. After three months of follow-up without any treatment, the retinal hemorrhages resolved without any sequelae. Here we report a patient with sudden visual loss and retinal hemorrhage.

• Journal of Nutrition and Health
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• v.34 no.8
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• pp.912-919
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• 2001

The increased oxidative stress may play an important role on the pathogenesis of diabetes and diabetic complications, and the blood level of vitamin C and lipid peroxidation in NIDDM patients may be used as an indicator for oxidative stress. However there is only scanty evidence on the blood level of vitamin C in NIDDM patients with or without diabetic complications. The study population consisted of 90 NIDDM patients(diabetes without complication, 48, and diabetes with complications, 42) and 41 normal subjects. The 42 diabetic complications were divided into 3 groups : 15 diabetic nephropathy, 18 diabetic neuropathy, 9 diabetic retinopathy. The anthropometric data and blood biochemical data were studied. The dietary intake was determined by 24 hour recall methods and food frequency questionnaire. The plasma concentrations of MDA and vitamin C were determined by fluorophotometer and HPLC respectively. 1) In blood lipoprotein study, diabetes with complication had higher level of TG than diabetes without complications, while no significant differences in total cholesterol, HDL, and LDL were shown. Diabetic neuropathy had the highest TG level among diabetic complication groups. 2) The intakes of vitamin B complexes(vitamin B$_2$, vitamin B$_{6}$, not vitamin B$_1$) and antioxidant vitamins(vitamin A and vitamin E, not vitamin C) and certain minerals such as iron and calcium in diabetes were not sufficient but the intakes of energy, protein, niacin, and phosphorus in diabetes were sufficient. The dietary intakes between diabetes with-and without complications were not significantly different. Among diabetic complications, the diabetic retinopathy had the lowest intake of vitamin B$_2$ and B$_{6}$(p < 0.05). the diabetic neuropathy or nephropathy consumed extremely low amount of vitamin A. 3) The MDA concentrations of NIDDM was significantly higher than that in controls(p < 0. 05) while no significant difference in the MDA concentration between with and without complications was shown. Although there were no statistical differences, the diabetic nephropathy and diabetic neuropathy showed the higher concentration of MDA than the diabetes without complications or diabetic retinopathy. 4) The plasma concentration of vitamin C in controls was higher than that in diabetes(p < 0.05) while the plasma vitamin C in diabetes with and without complications were similar. In diabetic complications, no differences in plasma vitamin C concentration of three groups were shown. This study showed that the oxidative stress in NIDDM patients was highly increased and the vitamin C reserve was significantly depleted, as compared with normals, although their intakes of vitamin C met korean RDA, which means that diabetes need more vitamin C intake to decrease oxidative stress in NIDDM patients.nts.

• Clinical and Experimental Pediatrics
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• v.52 no.1
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• pp.50-55
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• 2009

Purpose : This study aimed to determine the influence of low-dose oxygen ($FiO_2$ <25%) therapy through nasal cannulae on the progress and prognosis of retinopathy of prematurity (ROP) as well as methods of preventing ROP. Methods : Our subjects comprised premature infants (gestation period <37 weeks; birth weight <1,750 g) born in Daegu Fatima Hospital between February 1, 2001 and January 31, 2006. We retrospectively reviewed and analyzed the medical records of 273 patients who were available for eye examination and follow up over 6 months. Results : The factors maximally influencing the occurrence of ROP were low gestation age and low birth weight. We observed that the incidence of ROP increased with the increasing duration of low-dose oxygen therapy. ROP onset was delayed during ongoing oxygen therapy; however, rapid progression of ROP occurred after the discontinuation of oxygen therapy among premature infants up to the prethreshold stage. Conclusion : To prevent of occurrence of severe ROP and its rapid progression, the period of low-dose oxygen therapy needs to be shortened. Moreover, frequent eye examinations should be performed after the discontinuation of oxygen therapy.

• Toxicological Research
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• v.31 no.2
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• pp.157-163
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• 2015

Nanotechnology has advanced at an extremely rapid pace over the past several years in numerous fields of research. However, the uptake of nanoparticles (NPs) into the body after administration through various routes may pose a risk to human health. In this study, we investigated the potential ocular toxicity of 20-nm, negatively- charged zinc oxide (ZnO) NPs in rats using micro-computed tomography (micro-CT) and histopathological assessment. Animals were divided into four groups as control group, ZnO NPs treatment group (500 mg/kg/day), control recovery group, and ZnO NPs treatment and recovery group. Ocular samples were prepared from animals treated for 90 days (10 males and 10 females, respectively) and from recovery animals (5 males and 5 females, respectively) sacrificed at 14 days after final treatment and were compared to age-matched control animals. Micro-CT analyses represented the deposition and distribution of foreign materials in the eyes of rats treated with ZnO NPs, whereas control animals showed no such findings. X-ray fluorescence spectrometry and energy dispersive spectrometry showed the intraocular foreign materials as zinc in treated rats, whereas control animals showed no zinc signal. Histopathological examination revealed the retinopathy in the eyes of rats treated with ZnO NPs. Neuronal nuclei expression was decreased in neurons of the ganglion cell layer of animals treated with ZnO NPs compared to the control group. Taken together, treatment with 20-nm, negatively-charged ZnO NPs increased retinopathy, associated with local distribution of them in ocular lesions.

• Journal of The Korean Ophthalmological Society
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• v.59 no.12
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• pp.1137-1141
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• 2018

Purpose: We explored the mydriatic effects of injected intracameral epinephrine after phacoemulsification (PE) combined with phacovitrectomy to treat proliferative diabetic retinopathy (PDR). Methods: We enrolled 96 patients (96 eyes) who underwent phacovitrectomy to treat PDR; we used ImageJ software to measure pupil sizes and the ratios of pupil to cornea area (PCA) before and after PE and after pars plana vitrectomy (PPV). We compared pupil sizes between those who received intracameral epinephrine (0.001% w/v) after PE but before PPV (study group, 46 eyes) and patients not so treated (control group, 50 eyes). Results: The PCA ratios of the study group were $0.52{\pm}0.11$ before PE, $0.43{\pm}0.12$ after PE, and $0.51{\pm}0.11$ after PPV, respectively. Changes in pupil size were significant (p < 0.001, p < 0.001 respectively). The PCA ratios of the control group were $0.52{\pm}0.10$ before PE, $0.39{\pm}0.15$ after PE, and $0.43{\pm}0.15$ after PPV, respectively. Changes in pupil size after PE were significant (p = 0.011) but the change after PPV was not (p = 0.056). Conclusions: Intracameral epinephrine given after PE but before PPV effectively dilates the pupils during phacovitrectomy to treat PDR.

• Korean Journal of Ophthalmology
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• v.32 no.6
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• pp.451-458
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• 2018

Purpose: To investigate the efficacy, safety, and anatomical outcomes associated with intravitreal anti-vascular endothelial growth factor (VEGF) treatment of retinopathy of prematurity (ROP). Methods: We performed a retrospective review of intravitreal anti-VEGF (bevacizumab or ranibizumab) treatment of 153 eyes (83 infants) diagnosed with ROP at two tertiary hospitals from June 2011 to January 2017. The primary outcome was the rate of recurrence requiring additional treatment; secondary outcomes included incidence of major complications and final refractive error. Results: A total of 101 eyes were treated with bevacizumab, and 52 with ranibizumab. The bevacizumab and ranibizumab groups were characterized by mean birthweights of $941.8{\pm}296.1$ and $1,257.7{\pm}514.5g$, gestational ages at birth of $26.9{\pm}1.9$ and $28.1{\pm}3.2$ weeks, and postmenstrual ages at treatment of $40.4{\pm}2.4$ and $39.2{\pm}2.3$ weeks, respectively. The two groups differed significantly in birthweights and gestational ages at birth, but not in postmenstrual ages at treatment. The mean follow-up duration was $30.9{\pm}18.4$ months for the bevacizumab group, and $13.9{\pm}12.5$ months for ranibizumab. More cases were classified as zone 1 ROP in the ranibizumab group (44.2% vs. 11.9%, p < 0.001). Major surgical interventions included scleral encircling and vitrectomy (one and two eyes, respectively, both in the bevacizumab group). Retinal detachment was noted in one eye treated with bevacizumab. There was no significant difference in the most recent spherical equivalence for the two groups ($+0.10{\pm}3.66$ and $+0.22{\pm}3.00$ diopters for bevacizumab and ranibizumab, respectively). Univariable analysis revealed that only ROP stage influenced the occurrence of major complications (odds ratio, 9.046; p = 0.012). Conclusions: Intravitreal anti-VEGF treatment of ROP with both bevacizumab and ranibizumab achieved stable retinal vascularization with a low rate of complications and recurrence. Ranibizumab achieved similar anatomical outcomes as bevacizumab, without additional risk for major complications.