1.The Effect of Daunorubicin on Experimental Proliferative Vitreoretinopathy.
Jae Hyun LEE ; Hyung Woo KWAK ; Woo Jeong CHOI
Journal of the Korean Ophthalmological Society 1996;37(10):1656-1662
Proliferative vitreoretinopathy (PVR) is a main cause of failure in retinal reattachment surgery. There have been many studies about the inhibition of proliferative vitreoretinophthy with several drugs. Authors investigated the inhibitory effect of proliferative vitreoretinopathy and retinal toxicity with various concentration of daunorubicin after intravitreal injection into the eyes of the pigmented rabbit. 7 pigment rabbit (11eyes) were used as subjects. After lensectomy and vitrectomy, control group was injected dermal fibroblast and F-BSS, and treatment group was injected dermal fibroblast and 5, 10, 15, 30 nmol Daunorubicin. At two weeks after intravitreal injection, both group were enucleated and examined with gross finding, light--microscopy, and electronmicroscopy. In all control group, proliferative vitreoretinopathy was found, but only preretinal membrane formation was found in 5, 10 nmol Daunorubicin injected group. In 15 nmol Daunorubicin injected group, the retina structure was preserved normally. In 30 nmol Daunorubicin injected group, the retinal outer segment was degenerated in microscopic finding. These results show that Daunorubicin has a potent effect on proliferative vitreoretinopathy, especially in 15 nmol, but retinal toxicity is suspected in marethan 30 nmol.
Daunorubicin*
;
Fibroblasts
;
Intravitreal Injections
;
Membranes
;
Retina
;
Retinal Photoreceptor Cell Outer Segment
;
Retinaldehyde
;
Vitrectomy
;
Vitreoretinopathy, Proliferative*
2.Evaluation of Pattern-Reversal Retinal Potentials in Normal Groups.
Journal of the Korean Ophthalmological Society 1987;28(6):1271-1277
Pattern-reversal retinal potentials(PRRP) are electrical signals generated within retina, possibly by the retinal ganglion cells, when a phase-alternating check board pattern is viewed. Authors clinically studied the characteristics of PRRP the mean amplitude and latency with 24 minute checks, the effect of the spatial frequency, the effect of defocusing and the retinocortical time in 20 normals, using Nicolet CA 1,000. The results are as follows; 1. The mean latency P1 and the mean P1-N2 amplitude of PRRP in normal group was 39.19 +/- 3.30(msec), 1.32 +/- 0.22(uV), respectively. 2. The mean retinocortical time in normal group was 52.93 +/- 7.39(msec). 3. The P1-N2 amplitude of PRRP was reduced linearly with increasing defocusing, and significant amplitude reduction was observed when defocusing amounted to +1D. 4. When central 3 degree of stimulus was covered in order to simulate a macular pathology, PRRP to 24 minute checks was abnormal both in amplitude and latency. 5. Peak response amplitude of PRRP was obtained with large checksizes(3 degrees 12 minutes, 6 degrees 24 minutes).
Pathology
;
Retina
;
Retinal Ganglion Cells
;
Retinaldehyde*
3.A Case of Choroiditis Associated with IgA Nephropathy.
Journal of the Korean Ophthalmological Society 1987;28(5):1095-1099
The pathogenesis of IgA nephropathy is unknown, but the systemic character of the IgA deposits (skin and glomerular capillaries), the presence of circulating IgG and IgA complexes and its similarity to Henoch-Schonlein purpura suggest that it is an immune-complex mediated disease. The nature and source of the antigen are unknown. Anatomically, the extremely vascular uvea offers a favorable site for the interplay of various components of immune reaction. We have experienced a 21-year old male who had a choroiditis and IgA nephropathy and had suffered the Henoch-Schonlein purpura when he was 16-years old. We performed the choroidal aspiration and scleral buckling, but steroid and other specific therapy were not given. In the course of follow-up check, the choroidal lesion and hematuria were progressively subsided. In conclusion, we report that the choroiditis is manifested as a part of immunecomplex mediated disease associated with IgA nephropathy.
Adolescent
;
Choroid*
;
Choroiditis*
;
Follow-Up Studies
;
Glomerulonephritis, IGA*
;
Hematuria
;
Humans
;
Immunoglobulin A*
;
Immunoglobulin G
;
Male
;
Purpura, Schoenlein-Henoch
;
Scleral Buckling
;
Uvea
;
Young Adult
4.Effects of Preinduction Atropine on the Hemodynamic Response to Induction with Fentanyl and Vecuronium for Coronary Artery Bypass Grafting.
Hyun Jeong KWAK ; Woo Kyung LEE ; Geun Mo PARK ; Young Lan KWAK
Korean Journal of Anesthesiology 2003;44(5):626-632
BACKGROUND: Induction of anesthesia with a high dose of fentanyl and vecuronium decreases the heart rate and blood pressure. This study was designed to evaluate the effect of preinduction atropine on these hemodynamic changes in patients undergoing coronary artery bypass graft surgery (CABG). METHODS: Forty-one patients who underwent CABG were randomly divided into two groups. After insertion of a radial artery cannula and a Swan-Ganz catheter, normal saline 1 ml (control group, n = 20) or atropine 0.5 mg (atropine group, n = 21) was injected intravenously 1 min before the induction of anesthesia. Anesthesia was induced with a first dose of fentanyl (5-8 microgram/kg) and vecuronium (0.12 mg/kg) and a second dose of fentanyl (5-10 microgram/kg). The patient was then intubated. Hemodynamic variables were measured before the induction of anesthesia, 1 min after the administration of each drug during the induction of anesthesia and 5, 10, and 30 min after the intubation. RESULTS: There was no significant differences between the two groups in terms of demographic data except that the number of patients with diabetes mellitus was greater in the control group than in the atropine group. The number of patients treated for hypotension or bradycardia during the induction of anesthesia was greater in the control group than in the atropine group, but this was not statistically significant. Heart rates significantly decreased in the control group but were maintained in the atropine group without any significant tachycardia. Blood pressure significantly decreased in both groups. CONCLUSIONS: Intravenous injection of atropine before anesthetic induction in patients undergoing CABG attenuates the decrease in heart rate resulting from anesthetic induction with high dose fentanyl and vecuronium. However, it didn't prevent the decrease in blood pressure nor did it reduce the incidence of treatment for hypotension.
Anesthesia
;
Atropine*
;
Blood Pressure
;
Bradycardia
;
Catheters
;
Coronary Artery Bypass*
;
Coronary Vessels*
;
Diabetes Mellitus
;
Fentanyl*
;
Heart Rate
;
Hemodynamics*
;
Humans
;
Hypotension
;
Incidence
;
Injections, Intravenous
;
Intubation
;
Radial Artery
;
Tachycardia
;
Transplants
;
Vecuronium Bromide*
5.The Ocular Electrical Conductivity by Vitreous Substitutes in rabbits.
Journal of the Korean Ophthalmological Society 1993;34(7):613-618
Electrical conductivity of eyeball replaced with vitreous substitutes were also measured in both the non-enucleated and enucleated eye. The study of correlation between the electroretinogram and conductivity of eyeball to be replaced with vitreous substitutes was also evaluated. The electrical conductivity of each vitreous replacement was shown 74.5% in vitreous, 77.5% in saline, 100% in air and silicone oil respectively relative to standard material -1.5 battery, 100%. There was no difference of conductivity between the enucleated eye and non-enucleated eye. There were no correlation between the ERG amplitude and conductivity. As a result of experiments, the decrease in amplitude is suggested as a damage of retina by manipulation and surgery rather than decrease of conductivity with vitreous replacements.
Electric Conductivity*
;
Rabbits*
;
Retina
;
Silicone Oils
6.Determination of dexamethasone sodium phosphate in the vitreous by high performance liquid chromatography.
Hyung Woo KWAK ; Donald J D'AMICO
Korean Journal of Ophthalmology 1995;9(2):79-83
Dexamethasone sodium phosphate (DSP) is increasingly used in the treatment of ocular inflammatory diseases by systemic, periocular, and recently, intravitreal injection. We have developed a method for the determination of vitreous levels of DSP by reverse phase HPLC. In this method, co-elution of vitreous proteins with DSP is resolved by a prior sample clean-up procedure using Waters Sep-Pak C18 cartridge; the protein is separated and eluted with water while DSP, paraben and prednisone are eluted with methanol. DSP in the resulting sample is then separated by reverse phase HPLC and quantified by UV absorption at 254 nm. The recovery of DSP through the sample clean-up is 68.9 +/- 3.0%. DSP quantitation is linear from 0.1 mg to 1.0 mg per 1.0 ml vitreous. This method provides a simple, sensitive and reliable technique for determining the vitreous levels of DSP.
Animals
;
Anti-Inflammatory Agents/*analysis
;
Chromatography, High Pressure Liquid/*methods
;
Dexamethasone/*analogs & derivatives/analysis
;
Rabbits
;
Reproducibility of Results
;
Sensitivity and Specificity
;
Vitreous Body/*chemistry
7.Comparison of Betamethasone Concentration in Aqueous Humor Between Upper and Lower Fornix Subconjunctival Injection After Lens Delivery.
Hyung Woo KWAK ; Jung Hyoo MOON
Journal of the Korean Ophthalmological Society 1988;29(4):547-550
The purpose of this paper is to investigate the difference in concentration of 0.53% betamethasone in aqueour humor after betamethasone subconjunctival injection on upper and lower fornix after cataract extraction. A total of 8 rabbits were used. Cataract extractions were performed with the cryoprobe. After 6 hours, 0.53% betamethasone was subconjunctivally in upper fornix of the left eye and injected in lower fornix of the right eye. The control group of 3 rabbits underwent with the same procedures but the without lens delivery. the concentration of 0.53% betamethasone in aqueous humor was measured with HPLC(High Performance Liquid Chromatograph) after fine needle aspiration of aqueous humor. The results obtained were as follows. 1. In 5 eyes of the control group in 3 rabbits, 0.53%betamethasone was injected subconjunctivally on the lower fornix. The mean concentration of 0.53% betamethasone in aqueous humor was 0.544 +/- 0.0818 microgram/ml. 2. After 0.53% betamethasone subconjunctival injection on upper fornix after lens extraction, the mean concentration of 0.53% betamethasone in aqueous humor was 0.318 +/- 0.0117 microgram/ml. 3. After 0.53% betamethasone subconjunctival injection on lower fornix agter lens extraction, the mean concentration of 0.53%betamethasone in aqueous humor was 0.702 +/- 0.0332 microgram/ml. 4. The mean concentration of the betamethasone in aqueous humor after 0.53% betamethasone subconjunctival injection on lower fornix after lens extraction was significantly higher than on upper fornix(p<0.05).
Aqueous Humor*
;
Betamethasone*
;
Biopsy, Fine-Needle
;
Cataract Extraction
;
Rabbits
8.Comparison of Blood-Ocular-Barrier between White Rabbits and Colored Rabbits.
Chang Soo PARK ; Hyung Woo KWAK
Journal of the Korean Ophthalmological Society 1986;27(6):1037-1043
The purpose of this paper is to investigate the extent of destruction Blood-ocularbarrier between colored rabbits and white rabbits after photocoagulation, as preliminary experiment for the using colored and white rabbits. A total of 10 rabbits (5 white rabbits, 5 colored rabbits) were used. Photocoagulation in the right eye of 5 white rabbits and 5 colored rabbits were performed. The left eye of all the rabbits was control eye and the right eye was laser treated eye. After 3 days, a dose of 25mg/kg of 10% fluorescein sodium was injected in the ear vein of rabbit intravenously. We sampled aquous humor in anterior chamber and vitreous, and checked fluorescein concentration in anterior chamber and vitreous using HPLC (High Performance Liquid Chromatography). The results obtained were as follows; In experimental animals, 1. There is no significance between colored rabbits and white rabbits in fluorescein concentration of vitreous and aquous humor in control group. 2. The concentration of the fluorescein in the anterior chamber and vitreous of the right photocoagulated eye was higher than control eye, but there is no significance between colored rabbits and white rabbits. 3. there is no significance between colored rabbits and white rabbits in extent of destruction of Blood-ocular-barrier after Laser photocoagulation.
Animals
;
Anterior Chamber
;
Chromatography, High Pressure Liquid
;
Ear
;
Fluorescein
;
Light Coagulation
;
Rabbits*
;
Veins
9.Comparision of the Effects of Transpupillary Thermotherapy(TTT) of Pigmented and Albino Rabbit Retina.
Tae Kwann PARK ; Seung Young YU ; Hyung Woo KWAK
Journal of the Korean Ophthalmological Society 2001;42(5):762-771
PURPOSE: We compared the clinicopathologic effects of TTT between pigmented and albino rabbits. METHODS: TTT was delivered using infrared diode laser at 810 nm(Iris Medical Instrument, Mountain Veiw, CA, USA) and applied with spot size of 3 mm, duration of 60 seconds. At 1 week and 4 weeks after TTT, fundus photographs and simultaneous FAG/ICG angiogram were taken with SLO(Scanning Laser Ophthalmolscopy, Rodenstock, Munish, Germany). Light and electron microscopic examination were performed. RESULTS: In pigmented rabbits, visible funduscopic change was visible even with minimal power setting(100 mW). Obliteration of choroidal vessels was observed on ICG angiogram. In microscopic examination, entire layers of neural retina, retinal pigment epithelial cells, and deep choroid were severely damaged at the center of treated fields. Whereas, in albino rabbits fundus changes were not observed at any power setting. However, focal thrombosis at margin of lesion was identified on ICG angiogram after power of 300 mW. In microscopic examination, tissue damage was developed up to 600 mW and the lesion extended into the superficial choroid posteriorly and outer neural retina anterioly. CONCLUSIONS: The effect of TTT was increased with fundus pigmentation. Clinically we should adjust TTT power setting according to the amount of melanin pigmentation in the fundus.
Choroid
;
Epithelial Cells
;
Lasers, Semiconductor
;
Melanins
;
Pigmentation
;
Rabbits
;
Retina*
;
Retinaldehyde
;
Thrombosis
10.The Neuroprotective Effect of Intravitreal Melatonin Injection in Pressure-induced Retinal Ischemia.
Seung Joon LEE ; Won Sub SON ; Hyung Woo KWAK
Journal of the Korean Ophthalmological Society 2001;42(4):638-646
PURPOSE: The authors sought to determine the neuroprotective effect of melatonin in a model of ischemic injury in rabbit retina. METHODS: Ischemia was induced by high intraocualr pressure. A dose of 100 microgram of melatonin or dimethyl sulfoxide(DMSO) alone was injected intravitreally just after the induction of ischemia. After 7 and 14 days, the neuroprotective effect of melatonin on ischemic retina was examined with light microscope and transmission electron microscope. RESULTS: The authors found reduction of cytoplasm of retinal ganglion cell(RGC), vacuole formation, chromatin condensation and rupture of nuclear membrane in ischemia-injured eyes treated with DMSO alone. But in melatonin treated eyes, we found that RGC layer's thickness and number of RGC reduced and destruction of cytoplasmic organells and nuclear damage were minimal. The partial recovery of wave is noted in melatonin-treated eyes after ischemia induction. CONCLUSIONS: The melatonin(100 microgram) protected the rabbit retina from high intraocular pressure-induced ischemic injury when administered intravitreally. Melatonin may be useful to decrease neuronal damage in the retina as a result of ischemic injury. But further investigations are neccesary to decide effective concentration, route and time of administration.
Chromatin
;
Cytoplasm
;
Dimethyl Sulfoxide
;
Ganglion Cysts
;
Ischemia*
;
Melatonin*
;
Neurons
;
Neuroprotective Agents*
;
Nuclear Envelope
;
Retina
;
Retinaldehyde*
;
Rupture
;
Vacuoles