The Study on the Role of NMDA Receptors in Rat Visual Cortex

The amino acid L-glutamate is a major excitatory neurotransmitter in central nervous system of vertebrates. NMDA( n-methyl-d-aspartate) is one of the L-glutamate receptor subtypes. During a critical period of early postnatal development, the visual cortex is susceptible to experience-dependent modification of neuronal response. Recently, the activation of NMDA receptors has been supposed as an prerequisite for the induction of such modification We therefore investigated developmental changes of NMDA receptors in rat visual cortex and questioned whether they could be related to the visual development. We assessed the density of [3H] NMDA receptor in visual cortex of normally reared rats (Group I) and visually deprivated rats (Group II) using quantitative autoradiography. The density of [3H] NMDA receptor was increased rapidly by postnatal 1 week and decreased after postnatal 5 weeks, and was significantly lower in Group II than Group I during early postnatal period. These results suggest that NMDA receptors may have a role in neuronal development in visual cortex.

A study on the role of N-methyl-D-aspartate receptors in the rat visual cortex

The amino acid L-glutamate is a major excitatory neurotransmitter in the central nervous system of vertebrates(1). NMDA (N-methyl-d-aspartate) is one of the L-glutamate receptor subtypes(2). During a critical period of early postnatal development, the visual cortex is susceptible to experience-dependent modification of neuronal responses. Recently, the activation of NMDA receptors has been supposed as a prerequisite for the induction of such modification(3). We therefore investigated developmental changes of NMDA receptors in the rat visual cortex and questioned whether they could be related to the visual development. We assessed the density of [(3)H]-NMDA receptor in the visual cortex of normally reared rate (Group I) and visually deprived rats (Group II) using quantitative autoradiography(4). The density of [(3)H]-NMDA receptor was significantly lower in Group II than in group I during the early postnatal period, and increased rapidly by postnatal 1 week and, decreased after postnatal 5 weeks. These results suggested that NMDA receptors may play a role in neuronal development in the visual cortex during the early postnatal period.

Experimental Intraocular Fibrovascular Proliferation Through Sclerommy Wound

In the process of closing a scleral wound caused by various conditions, incarceration af the conjunctiva, Tenon's capsule or vitreous in the wound can occur unexpectedly. We created such conditions experimentally to determine their intraocular complications. The experimental, materials were 12 albino rabhits(24 eyes) and the rabbits were divided into two groups(I and II). Group I rabbits(12 eyes) received no vinectormy and group II rabbits(12 eyes) received a vitrectormy. After the conjunctiva and Tenon's capsule flap was made, the tissue flap was inserted into the vitreous cavity through the sclerotomy site- Fundus examination with an indirect ophthalmoscope and enucleation for histology were performed at 3 days, 1 week, 3 weeks, 6 weeks, 3 months and 6 months after the experiment. The results were as follows: 1, Intraocular fibrovascular proliferation developed in all experimental rabbit eyes. 2. The more vitreous hemorrhage developed, the greater was the fibrovascular proliferation and the degree of fibrovascular proliferation was more marked in group II than group I. 3. The fibrovascular proliferation developed to a band in 3 weeks, then regressed gradually. 4. The fibrovascular band was composed of fibroblasts, stromal matrix and few vessels.

Experimental Intraocular Fibrovascular Proliferation Through Sclerommy Wound

In the process of closing a scleral wound caused by various conditions, incarceration af the conjunctiva, Tenon's capsule or vitreous in the wound can occur unexpectedly. We created such conditions experimentally to determine their intraocular complications. The experimental, materials were 12 albino rabhits(24 eyes) and the rabbits were divided into two groups(I and II). Group I rabbits(12 eyes) received no vinectormy and group II rabbits(12 eyes) received a vitrectormy. After the conjunctiva and Tenon's capsule flap was made, the tissue flap was inserted into the vitreous cavity through the sclerotomy site- Fundus examination with an indirect ophthalmoscope and enucleation for histology were performed at 3 days, 1 week, 3 weeks, 6 weeks, 3 months and 6 months after the experiment. The results were as follows: 1, Intraocular fibrovascular proliferation developed in all experimental rabbit eyes. 2. The more vitreous hemorrhage developed, the greater was the fibrovascular proliferation and the degree of fibrovascular proliferation was more marked in group II than group I. 3. The fibrovascular proliferation developed to a band in 3 weeks, then regressed gradually. 4. The fibrovascular band was composed of fibroblasts, stromal matrix and few vessels.

Experimental intraocular fibrovascular proliferation through sclerotomy wound

In the process of closing scleral wounds caused by various conditions, incarceration of conjunctiva, Tenon's capsule, or vitreous in the wound can occur unexpectedly. We created such conditions experimentally in order to discover their intraocular complications. The experimental materials consisted of 12 albino rabbits (24 eyes) divided into two groups (Groups I & II). Vitrectomy was performed in the Group I rabbits (12 eyes) but not in the Group II rabbits (12 eyes). Flaps of conjunctiva and Tenon's capsule were made and inserted into the vitreous cavity through the sclerotomy site, which was soon closed. Fundal examination of the rabbits was carried out using an indirect ophthalmoscope at intervals after the procedure; first at 3 days, then at 1, 3, and 6 weeks, and then at 3 months and 6 months, respectively. Enucleation of the rabbits' eyes 4 from two different rabbits at each of these intervals was carried out, and the extracted eyes were examined under a light microscope at each interval. The results are summarized as follows: 1. All rabbit eyes studied showed intraocular fibrovascular proliferation. 2. The extent of tissue proliferation, which was proportional to the amount of vitreous hemorrhage, was greater in Group II than in Group I. 3. The proliferated tissue developed to "band" by three weeks postexperiment, after which it gradually regressed. 4. The fibrovascular band was made of fibroblasts, stromal matrix, and capillaries.

Clinical Analysis on Focal Laser Treatment of Diabetic Maculopathy

Diabetic maculopathy which is the major cause of blindness in nonproliferative diabetic retinopathy, has been treated clinically with laser photocoagulation. We reviewed 21 cases(26 eyes) of diabetic maculopathy which were treated by focal laser treatment and followed up for more than 6 months from January 1984 to December 1988. The results were as follows: 1. There was improvement of the visual acuity in 19 eyes(71.1%), no changes in 5 eyes(19.2%), and only two eyes(7.7%) showed worsened visual acuity. 2. The two eyes which showed worsened visula acuity after treatment showed stage IV of diabetic maculopathy.

Two Cases of Sympathetic Ophthalmia After Ocular Surgery

Sympathetic ophthalmia is rare, bilateral, diffuse, and granulomatous inflammation of the uvea, which occurs days, months, or years after penetrating ocular injury or intraocular surgery. The cause of the disease is still unknown but seems to be an autoimmune disease by reaction of delayed hypersensitivity mediated by T-Iymphocyte. There have been 4 cases reports on sympathetic ophthalmia domestically untill now, which occurred after ocular penetrating injury. The authors experienced two cases of sympathetic ophthalmia; one occurred after implantation of intraocular lens and the other occurred after cyclocryotherapy. A brief review of the related literatures is presented.

Two Cases of Sympathetic Ophthalmia After Ocular Surgery

Sympathetic ophthalmia is rare, bilateral, diffuse, and granulomatous inflammation of the uvea, which occurs days, months, or years after penetrating ocular injury or intraocular surgery. The cause of the disease is still unknown but seems to be an autoimmune disease by reaction of delayed hypersensitivity mediated by T-Iymphocyte. There have been 4 cases reports on sympathetic ophthalmia domestically untill now, which occurred after ocular penetrating injury. The authors experienced two cases of sympathetic ophthalmia; one occurred after implantation of intraocular lens and the other occurred after cyclocryotherapy. A brief review of the related literatures is presented.

The effect of Contact Lens Wear on Tear Secretion

Tear film consists of lipid layer, aqueous layer, and mucinous layer, and it acts as protection of cornea, nutritional supply, and refraction. The assumption of this study is that the use of contact lens may induce the rapid drainage of tear film, and may make it become thin, and may affect the function of corneal epithelium, and may induce several complication. The author analysed 168 volunteers of medical students. The volunteers consisted of junior and senior grades in Ewha Womans University were classified into two groups. One group was the users of contact lenses(70), and the other group was non-users of contacts lenses who have not any other ocular problems control group(98). The purpose of this study was to evaluate the influence of tear secretion in fitting contact lens. The results were as follows; 1. Mean value and standard deviation of Schirmer test showed; contact lens group was 20.5 +/- 8.0mm/5min, and control group was 21.2 +/- 8.2mm/5min. There was no statistical significance between two groups. 2. The author could not obtain the statistical difference the users of soft contact lenses and the users of hard contact lenses, because the number of the users of hard contact lenses was so small in contrast to that of the users of soft contact lenses. 3. There was no significant correlation between daily wearing time and the result of Schimer test. 4. The correlation between the wearing period of contact lens and the result of Schirmer test showed; the longer wearing period of contact lens was, the longer wetting length of Schirmer test paper was, but it was not statistically significant. The authors concluded that the use of contact lens does not affect the secretion of tear.

Clinical Analysis of Choroidal Ruptures

Choroidal rupture is a common complication of contusion injuries of the eye. The data from 53 patients of choroidal ruptures attending SNUH for 6 years were analyzed. 1. There were more males than females and the peak age was twenties and thirties of age. 2. There was no statistical diffenence in frequency of left or right eye injuries. 3. The major(55%) chief complaint of the patients was visual disturbance. 4. The majority(36%) of the patients visited SNUH from 11 days to 1 month after the ocular trauma. 5. The major(34%) cause of ocular trauma was a blow by fist or foot. 6. Most(79%) of the corrected visual acuities on initial examination were 0.3 or less. 7. The majority(45%) of the choroidal ruptures were 1-2 disc diopter in length. 8. Most(75%) of the choroidal ruptures were single in number. 9. The majority(59%) of the choroidal ruptures were in the posterior pole and/or near the posterior pole and most(82%) of choroidal ruptures were located temporal to the optic disc. 10. The majority(72%) of the choroidal ruptures were associated with macular lesions, e.g., choroidal rupture, subretinal neovascular membrance, hemorrhage and degeneration, etc. 11. Fluorescein angiographic findings of choroidal ruptures were scleral staining(100%), subretinal pigment epithelial hemorrhage(37%), pigment hypertrophy(19%), subretinal hemorrhage(15%), and subretinal neovascular membrane(11%), etc. 12. In 15% of the choroidal ruptures, subretinal neovascular membrane developed.

Two Cases of the Metastatic Endophthalmitis

The endophthalmitis is an ophthalmic emergency and it usually takes a tragic course, so its early diagnosis and appropriate treatment are urgently mandatory to preserve the vision and the eyeball. The authors found metastatic endophthalmitis developed during the course of acute pyelonephritis of two diabetic patients. In spite of aggressive topical and systemic managements, the disesed eyes were brought about to enucleation. The pathogens were proved to be Escherichia coli by culture of the specimen obtained from the vitreous. In accordance with cases and book review, it is emphasized that early recognition and aggressive treatments are essential in prevention of phthisis and blindness.

Two Cases of the Metastatic Endophthalmitis

The endophthalmitis is an ophthalmic emergency and it usually takes a tragic course, so its early diagnosis and appropriate treatment are urgently mandatory to preserve the vision and the eyeball. The authors found metastatic endophthalmitis developed during the course of acute pyelonephritis of two diabetic patients. In spite of aggressive topical and systemic managements, the disesed eyes were brought about to enucleation. The pathogens were proved to be Escherichia coli by culture of the specimen obtained from the vitreous. In accordance with cases and book review, it is emphasized that early recognition and aggressive treatments are essential in prevention of phthisis and blindness.