Factors Affecting ISNT Rule Satisfaction in Normal and Glaucomatous Eyes

PURPOSE: To determine the factors that influence the satisfaction of the ‘ISNT rule’ (neural rim width: inferior ≥ superior ≥ nasal ≥ temporal) in normal and glaucomatous eyes. METHODS: The medical records of patients that visited Boramae Medical Center, Seoul, Korea, were reviewed. Each group of normal and glaucomatous eyes was divided into subgroups based on whether or not they satisfied the ISNT rule. ISNT rule assessment was performed by measuring the rim width with stereoscopic optic disc photographs using ImageJ software. Logistic regression analysis was performed to determine the factors that affect ISNT rule satisfaction. RESULTS: Seventy-seven normal eyes and 97 glaucomatous eyes were included in the study. The ISNT rule was intact in 59 (76.6%) of the normal eyes and was violated in 71 (73.2%) of the glaucomatous eyes. Logistic regression analysis revealed a significant influence of axial length in violation of the ISNT rule in the normal eye group, while the mean deviation value was a significant factor for violation of the ISNT rule in the glaucomatous eye group. CONCLUSIONS: The ISNT rule should be cautiously applied when evaluating normal eyes with long axial lengths. In addition, the ISNT rule might not be as effective for detecting early glaucoma.

Amniotic Membrane Transplantation for Repair of a Large Intraoperative Conjunctival Defect during Trabeculectomy

No abstract available.

Patterns of Subsequent Progression of Localized Retinal Nerve Fiber Layer Defects on Red-free Fundus Photographs in Normal-tension Glaucoma

PURPOSE: To investigate patterns of subsequent progression of localized retinal nerve fiber layer (RNFL) defects and to quantify the extent of progression in normal-tension glaucoma (NTG) patients. METHODS: Thirty-three eyes of 33 consecutive NTG patients who had shown continuous progression of localized RNFL defect on serial red-free fundus photographs were selected for the study. Patterns of subsequent progression of localized RNFL defects were categorized, and extents of progression were quantified. Serial evaluations of disc stereophotographs and visual fields were also performed to detect progression. RESULTS: The most common pattern was continuous widening of the defect towards the macula (n = 11, 33.3%) followed by sharpening of the defect border after widening of the defect towards the macula (n = 5, 15.2%), continuous widening of the defect away from the macula (n = 2, 6.1%), and deepening of the defect after appearance of a new defect (n = 2, 6.1%). Four eyes (12.1%) simultaneously showed two patterns of subsequent progression. In 13 eyes that showed continuous widening of the defect, subsequent angular widening towards the macula and away from the macula were 9.2 ± 6.0degrees (range, 1.1degrees to 24.4degrees; n = 11) and 5.2 ± 4.9degrees (range, 0.3degrees to 11.3degrees; n = 2), respectively. Thirty-two eyes showed no progression of optic disc cupping. Out of the 21 eyes in which Humphrey central 30-2 threshold visual field tests were performed after progression of RNFL defects, 15 eyes showed no deterioration in the visual field. CONCLUSIONS: There were nine patterns of subsequent progression of localized RNFL defects. Among them, continuous RNFL loss proceeding temporally was the most common one. Initial progression of the defect proceeded temporally, especially in the defect located at the inferior fundus, might be at a risk of further RNFL loss temporally.

Location of the Tube Tip in the Anterior Chamber and Change in Corneal Endothelium after Ahmed Valve Implantation

PURPOSE: To evaluate the impact of location of a silicone tube tip in the anterior chamber on corneal endothelium after Ahmed glaucoma valve implantation. METHODS: We measured the distance from the tip of a silicone tube in the anterior chamber to the posterior surface of the cornea by anterior segment optical coherence tomography (OCT) in 24 eyes of 21 patients who underwent Ahmed glaucoma valve implantation. All surgeries were performed by a single surgeon. The corneal endothelial cells of central, superior, superotemporal, and superonasal area of the cornea were examined by specular microscope before and after surgery. RESULTS: The distance from the tip of the silicone tube in the anterior chamber to the posterior surface of the cornea and the corneal endothelium were measured at 19.2 +/- 11.8 months (2.8-41.2 months) after surgery. At the central corneal area, a statistically significant decrease in the number of corneal endothelial cells (2278 +/- 565/mm2 vs. 2177 +/- 529/mm2, p = 0.043) after surgery was observed, but no relationship was found between the amount of decrease and distance from the tip to the posterior surface of the cornea. At the superotemporal corneal area where the tip of the silicone tube was located in the anterior chamber, there was more significant loss of corneal endothelial cells than in the other areas after surgery (p = 0.006). Moreover, the amount of endothelial cell loss at the superotemporal area was negatively correlated to the distance from the tip to the posterior surface of the cornea (partial correlation coefficient by time -0.558, p = 0.031). CONCLUSIONS: To minimize the loss of corneal endothelial cells after Ahmed glaucoma valve implantation, ensuring a sufficient distance from the tip of the silicone tube to the posterior surface of the cornea is important.

Anterior Chamber Configuration Changes after Cataract Surgery in Eyes with Glaucoma

PURPOSE: To evaluate changes in anterior chamber depth (ACD) and angle width induced by phacoemulsification and intraocular lens (IOL) implantation in eyes with glaucoma, using anterior segment optical coherence tomography (AS-OCT). METHODS: Eleven eyes of 11 patients with angle-closure glaucoma (ACG) and 12 eyes of 12 patients with open-angle glaucoma (OAG) underwent phacoemulsification and IOL implantation. Using AS-OCT, ACD and angle parameters were measured before and 2 days after surgery. Change in intraocular pressure (IOP) and number of ocular hypotensive drugs were evaluated. RESULTS: After surgery, central ACD and angle parameters increased significantly in eyes with glaucoma (p < 0.05). Prior to surgery, mean central ACD in the ACG group was approximately 1.0 mm smaller than that in the OAG group (p < 0.001). Post surgery, mean ACD of the ACG group was still significantly smaller than that of the OAG group. No significant differences were found in angle parameters between the ACG and OAG groups. In the ACG group, postoperative IOP at the final visit was significantly lower than preoperative IOP (p = 0.018) and there was no significant change in the number of ocular hypotensive medications used, although clinically, patients required fewer medications. In the OAG group, the IOP and number of ocular hypotensive drugs were almost unchanged after surgery. CONCLUSIONS: The ACD and angle width in eyes with glaucoma increased significantly after phacoemulsification and IOL implantation. Postoperative ACD significantly differed between the ACG and OAG groups, whereas angle parameters did not differ.

Changes in Anterior Chamber Configuration after Cataract Surgery as Measured by Anterior Segment Optical Coherence Tomography

PURPOSE: To evaluate the changes in anterior chamber depth (ACD) and angle width induced by phacoemulsification and intraocular lens (IOL) implantation in normal eyes using anterior segment optical coherence tomography (AS-OCT). METHODS: Forty-five eyes (45 patients) underwent AS-OCT imaging to evaluate anterior chamber configuration before and 2 days after phacoemulsification and IOL implantation. We analyzed the central ACD and angle width using different methods: anterior chamber angle (ACA), trabecular-iris angle (TIA), angle opening distance (AOD), and trabecular iris surface area (TISA) in the nasal and temporal quadrants. Comparison between preoperative and postoperative measurement was done using paired t-tests and each of the angle parameters was analyzed with Pearson correlation testing. Subgroup analyses according to the IOL and axial length were performed with a general multivariate linear model adjusted for age. RESULTS: Before surgery, the mean anterior chamber angle widths were 23.21 +/- 6.70degrees in the nasal quadrant and 24.89 +/- 7.66degrees in the temporal quadrant. The mean central ACD was 2.75 +/- 0.43 mm. After phacoemulsification and IOL implantation, the anterior chamber angle width increased significantly to 35.16 +/- 4.65degrees in the nasal quadrant (p = 0.001) and 36.03 +/- 4.86degrees in the temporal quadrant (p = 0.001). Also, central ACD increased to 4.14 +/- 0.31 mm (p = 0.001). AOD, TISA, and TIA increased significantly after cataract surgery and showed positive correlation with ACA. CONCLUSIONS: After cataract surgery, the ACD and angle width significantly increased in eyes with cataract. AS-OCT is a good method for obtaining quantitative data regarding anterior chamber configuration.

Circadian Blood Pressure and Intraocular Pressure Patterns in Normal Tension Glaucoma Patients with Undisturbed Sleep

PURPOSE: To investigate and compare the circadian pattern of blood pressure (BP), intraocular pressure (IOP) and mean ocular perfusion pressure (MOPP) while experiencing undisturbed sleep in normal-tension glaucoma (NTG) and non-glaucoma control patient groups. METHODS: Twenty-four eyes from 24 patients diagnosed with NTG and 22 eyes from 22 control group patients were enrolled. Systolic BP, diastolic BP and IOP were measured every two hours except for the period of time from 1 AM to 7 AM in the NTG group and from 11 PM to 7 AM in the control group over a one-day period. IOP and hemodynamic parameters were then compared between the two groups. NTG patients were subdivided according to the degree of morning BP dip and IOP, and hemodynamic parameters and visual field indices (mean deviation and pattern standard deviation) were also compared among these subgroups. RESULTS: There were no significant differences in mean systolic BP, mean diastolic BP and mean arterial pressure (MAP) between the NTG and the control groups. The NTG group showed a significantly large morning BP dip compared to the control group (7.1+/-4.2% vs. 3.8+/-3.4%, p=0.022). However, there were no significant differences in mean or fluctuation of MOPP between the two groups. Morning over-dippers showed significantly large MAP and MOPP fluctuations compared to non-dippers and dippers, while there were no significant differences in visual field indices among the three subgroups. CONCLUSIONS: NTG patients showed significant morning BP dips compared to the control group. The marked morning BP dip was associated with significantly large MAP or MOPP fluctuations but was not associated with visual field indices.

Clinical Outcomes of Ahmed Glaucoma Valve Implantation Using Tube Ligation and Removable External Stents

PURPOSE: To investigate the immediate and long-term outcomes of Ahmed glaucoma valve (AGV) implantation with silicone tube ligation and removable external stents. METHODS: This retrospective non-comparative study investigated the outcomes of AGV implantation with silicone tube ligation and removable external stents in 95 eyes (90 patients) with at least 12 months of postoperative follow-up. Qualified success was defined as an intraocular pressure (IOP) of or =6 mmHg regardless of anti-glaucoma medication. Those who required additional glaucoma surgery, implant removal or who had phthisis bulbi were considered failures. Hypotony was defined as an IOP of <6 mmHg. RESULTS: Mean IOP reduced from 37.1+/-9.7 mmHg preoperatively to 15.2+/-5.6 mmHg at 12 months postoperatively (p<0.001). Qualified success was achieved in 84.2% at 1 year. Hypotony with an IOP of <6 mmHg was seen in 8.4% and an IOP of <5 mmHg in 3.2% on the first postoperative day. No case of hypotony required surgical intervention. Suprachoroidal hemorrhage did not occur in this study. When stents were removed on the first postoperative day because of an insufficient IOP decrease, the mean IOP decreased significantly from 42.0 mmHg to 14.1 mmHg (p<0.001) after 1 hour. The most common complication was hyphema, which occurred in 17.9%. CONCLUSIONS: Hypotony-related early complications requiring surgical intervention were reduced by ligation and external stents in the tube. In addition, early postoperative high IOPs were managed by removing external stents. The described method can prevent postoperative hypotony after AGV implantation and showed long-term success rates comparable to those reported previously.

Differences in the Histopathology and Matrix Metalloproteinase Expression in Tenon's Tissue of Primary Open-Angle Glaucoma and Primary Angle-Closure Glaucoma

PURPOSE: To investigate the differences in the histopathology and matrix metalloproteinase (MMP) expression in the Tenon's tissue of primary open-angle glaucoma (POAG) patients, primary angle-closure glaucoma (PACG) patients, and non-glaucomatous patients. METHODS: POAG and PACG patients, who underwent a trabeculectomy and had no history of ocular disease except glaucoma, were enrolled. The number and instillation period of topical eye drops were reviewed. For the controls, which were patients without glaucoma or a history of ocular surgery, the Tenon's tissue was obtained in the course of retinal detachment surgery. For glaucoma patients, the Tenon's tissue was obtained during the trabeculectomy. H&E and Masson's trichrome staining and immunohistochemistry for MMP-1, MMP-2, and MMP-9 were performed. A total of six eyes of POAG, six eyes of PACG, and four control eyes were evaluated. RESULTS: The duration of topical anti-glaucoma medication and the mean number of anti-glaucoma medications were similar in the POAG and PACG groups. The levels of MMP-1 and 2 were elevated in the POAG and PACG groups compared to the control group (p=0.03, 0.01, respectively). Compared with the control group, the MMP-2 level was higher in the POAG patients (p=0.01), whereas the MMP-1 was higher in the PACG patients (p=0.04). The levels of MMP-9 in the POAG and PACG patients were not significantly different from that of the control patients (p=0.48, 0.26). The levels of MMP-2 were significantly lower in the PACG patients than in the POAG patients (p=0.02). CONCLUSIONS: The MMP expression was altered in the Tenon's tissue of glaucoma patients compared to the control group. The levels of MMP-2 were lower in the PACG patients than in the POAG patients. These results suggest that there may be histopathological differences in the Tenon's tissue of POAG and PACG patients.

Differences in the Histopathology and Matrix Metalloproteinase Expression in Tenon's Tissue of Primary Open-Angle Glaucoma and Primary Angle-Closure Glaucoma

PURPOSE: To investigate the differences in the histopathology and matrix metalloproteinase (MMP) expression in the Tenon's tissue of primary open-angle glaucoma (POAG) patients, primary angle-closure glaucoma (PACG) patients, and non-glaucomatous patients. METHODS: POAG and PACG patients, who underwent a trabeculectomy and had no history of ocular disease except glaucoma, were enrolled. The number and instillation period of topical eye drops were reviewed. For the controls, which were patients without glaucoma or a history of ocular surgery, the Tenon's tissue was obtained in the course of retinal detachment surgery. For glaucoma patients, the Tenon's tissue was obtained during the trabeculectomy. H&E and Masson's trichrome staining and immunohistochemistry for MMP-1, MMP-2, and MMP-9 were performed. A total of six eyes of POAG, six eyes of PACG, and four control eyes were evaluated. RESULTS: The duration of topical anti-glaucoma medication and the mean number of anti-glaucoma medications were similar in the POAG and PACG groups. The levels of MMP-1 and 2 were elevated in the POAG and PACG groups compared to the control group (p=0.03, 0.01, respectively). Compared with the control group, the MMP-2 level was higher in the POAG patients (p=0.01), whereas the MMP-1 was higher in the PACG patients (p=0.04). The levels of MMP-9 in the POAG and PACG patients were not significantly different from that of the control patients (p=0.48, 0.26). The levels of MMP-2 were significantly lower in the PACG patients than in the POAG patients (p=0.02). CONCLUSIONS: The MMP expression was altered in the Tenon's tissue of glaucoma patients compared to the control group. The levels of MMP-2 were lower in the PACG patients than in the POAG patients. These results suggest that there may be histopathological differences in the Tenon's tissue of POAG and PACG patients.

Personal Privacy Protection of Electronic Medical Record in Health Information System / 대한의료정보학회지

OBJECTIVE: The consolidation of health information has led to the creation of a national network of medical institutions. In this wireless and hard-line communication web, patients' medical information, which is extremely private and must be kept in secret, may leak out, and the risk of dangers such as privacy infringement and misuse of information has increased. METHODS: For this dissertation, a patient information protection algorithm was designed for a hospital information system in order to improve the untraceability and anonymity of patients' individual information in a ubiquitous computing environment. RESULTS: Additionally, analyzing the computing load showed that the computing load of the entire system did not increase, and since 57 percent of the sensor node's computing load was transferred to the secure server, the sensor node's load was minimized. Thus, the system can also be applied to low performance sensor networks. CONCLUSION: In conclusion, improving the security level of identification information transmissions while minimizing the computing and communication load of sensor nodes in a ubiquitous computing environment did not lead to an increase in the system's overall computing or communication load. Thus, a system with improved security features for identification information and communication information was developed and established.

Investigation of the Association between Normal-tension Glaucoma and Single Nucleotide Polymorphisms in Natriuretic Peptide Gene

PURPOSE: The expression of natriuretic peptides in the neural bundles of the anterior portion of the optic nerves and their functions in regulating vessel tone and blood flow may suggest a possible role in the pathogenesis of glaucoma. The purpose of this study was to investigate the association between normal-tension glaucoma and the genetic variations of atrial natriuretic peptide (Nppa) and natriuretic peptide receptor A (Npr1) gene. METHODS: Sixty-seven Korean normal-tension glaucoma (NTG) patients and 100 healthy subjects (as normal controls) were enrolled. DNA from peripheral blood leukocytes was extracted, and the genotypes of five polymorphisms (c.94G>A, c.454T>C, IVS1+16C>T, IVS2+701G>A, and c.-764C>G) in the Nppa gene and one polymorphism (c.1023G>C) in the Npr1 gene were determined using the restriction fragment length polymorphism and the SNaPshot methods. The genotype and allele frequencies of these polymorphisms in patients with NTG and normal controls were compared using the Fisher's exact test and the chi-square test. RESULTS: In both groups, the genotype distributions were in accordance with the Hardy-Weinberg equilibrium. There was no significant difference in the frequency of the Nppa and Npr1 alleles or genotypes in the normal-tension glaucoma group as compared to the control group. CONCLUSIONS: Nppa and Npr1 gene polymorphisms are not associated with normal-tension glaucoma, suggesting that this gene does not have an important role in the pathogenesis of optic neuropathy in this disease.

The Detection of Retinal Never Fiber Layer Defect by Modification of Non-mydriatic Digital Fundus Photograph

PURPOSE: To evaluate the efficiency of digital retinal nerve fiber layer (RNFL) photographs converted from a non-mydriatic digital fundus camera for detecting RNFL defects. METHODS: Ninety-five eyes were evaluated with both a non-mydriatic digital fundus photograph and a digital RNFL photograph by two glaucoma specialists independently. The red-free, monochrome modified digital fundus photograph was acquired from non-mydriatic digital fundus photographs using Photoshop 7.0. Whether a localized wedge-shaped or diffuse RNFL defect existed or not was evaluated on a non-mydriatic digital fundus photograph and a modified digital fundus photograph, and inter- and intraobserver agreement were also evaluated. Regarding the use of digital RNFL photographs as a standard method, we calculated the sensitivity, specificity, and positive and negative predictive values of the two types of photographs. RESULTS Interobserver agreement (Cohen's kappa values) about localized RNFL defects observable on digital RNFL photographs, non-mydriatic digital fundus photographs, and modified digital fundus photographs were 0.749, 0.634, and 0.793, respectively, but all were 0.417 or less with regard to diffuse RNFL defects. Regarding localized RNFL defects, the sensitivity, specificity, and positive and negative predictive values of modified digital fundus photographs were 85.7%, 95.5%, 85.7% and 94.1%, respectively, showing superiority to those of non-mydriatic digital fundus photographs. But, in cases of diffuse RNFL defect, the sensitivity and specificity of modified digital fundus photographs were 60.0% and 97.8%, respectively, indicating no superiority to non-mydriatic digital fundus photographs. CONCLUSIONS: The localized RNFL defect can be detected more efficiently with modified digital fundus photographs than non-mydriatic digital fundus photographs, but the diffuse RNFL defect cannot.

The Detection of Retinal Never Fiber Layer Defect by Modification of Non-mydriatic Digital Fundus Photograph

PURPOSE: To evaluate the efficiency of digital retinal nerve fiber layer (RNFL) photographs converted from a non-mydriatic digital fundus camera for detecting RNFL defects. METHODS: Ninety-five eyes were evaluated with both a non-mydriatic digital fundus photograph and a digital RNFL photograph by two glaucoma specialists independently. The red-free, monochrome modified digital fundus photograph was acquired from non-mydriatic digital fundus photographs using Photoshop 7.0. Whether a localized wedge-shaped or diffuse RNFL defect existed or not was evaluated on a non-mydriatic digital fundus photograph and a modified digital fundus photograph, and inter- and intraobserver agreement were also evaluated. Regarding the use of digital RNFL photographs as a standard method, we calculated the sensitivity, specificity, and positive and negative predictive values of the two types of photographs. RESULTS Interobserver agreement (Cohen's kappa values) about localized RNFL defects observable on digital RNFL photographs, non-mydriatic digital fundus photographs, and modified digital fundus photographs were 0.749, 0.634, and 0.793, respectively, but all were 0.417 or less with regard to diffuse RNFL defects. Regarding localized RNFL defects, the sensitivity, specificity, and positive and negative predictive values of modified digital fundus photographs were 85.7%, 95.5%, 85.7% and 94.1%, respectively, showing superiority to those of non-mydriatic digital fundus photographs. But, in cases of diffuse RNFL defect, the sensitivity and specificity of modified digital fundus photographs were 60.0% and 97.8%, respectively, indicating no superiority to non-mydriatic digital fundus photographs. CONCLUSIONS: The localized RNFL defect can be detected more efficiently with modified digital fundus photographs than non-mydriatic digital fundus photographs, but the diffuse RNFL defect cannot.

Comparison of the Results between Heidelberg Retina Tomography II and Stratus Optical Coherence Tomography in Glaucoma

PURPOSE: To evaluate the ability of Stratus OCT and HRT II with Moorfields' analysis to detect localized RNFL defects and to evaluate the accordance of Stratus OCT and HRT II results in glaucoma patients. METHODS: A total of 60 patients (119 eyes) who had localized RNFL defects of either eye in red-free fundus photographs unserwent evaluation by Stratus OCT and HRT II. For the results of Stratus OCT and HRT II with Moorfields' analysis, normal distribution percentiles less than 5% were considered a significant RNFL defect. For each disc, superotemporal and inferotemporal portions were evaluated. The diagnostic abilities of Stratus OCT and HRT II to detect localized RNFL defects were calculated. The results of HRT II were compared with those of Stratus OCT. RESULTS: The overall sensitivity, specificity, positive predictive value and negative predictive value to detect localized RNFL defects were 67.9%, 88.9%, 84.3% and 76.5% in Stratus OCT and 67.3%, 64.8%, 62.2% and 69.6% in HRT II, respectively. Compared with Stratus OCT, 67.2% of HRT II results were in accord in the superotemporal portion and 68.9% in the inferotemporal portion. The accordance of detection of RNFL defects between the two instruments in the inferotemoral portion was higher (79.2%) than others. CONCLUSIONS: Stratus OCT with a normative database is a useful aid to detect localized RNFL defects in early glaucoma. If observation of topographic changes of the optic disc with HRT II is added, results will be even better.

Assessment of Retinal Ganglion Cell using Retinal Nerve Fiber Layer Photography in Age-related Macular Degeneration

PURPOSE: To determine the loss of ganglion cell layer (GCL) neurons in patients with age-related macular degeneration (AMD) with choroidal neovascularization (CNV). METHODS: Retinal nerve fiber layer (RNFL) photography was taken in patients with AMD with CNV to assess the presence of RNFL defects in the papillomacular bundle area. Patients with other ocular disorders or a history of previous intraocular surgery or laser treatment were excluded from this study. RESULTS: Eighty-five eyes in 65 patients were included, of which only one (1.2%) showed papillomacular bundle defects in association with CNV. CONCLUSIONS: From this study, the majority of the patients with AMD with CNV had no papillomacular bundle defect, which demonstrates that considerable amount of GCL is maintained in AMD.

The Neuroprotective Effect of Intravitreally Injected CNTF on Rat Retinal Ganglion Cell in Optic Nerve Crush Injury Model

PURPOSE: To make an optic nerve crush injury model and to investigate the neuroprotective effect of intravitreally injected ciliary neurotrophic factor (CNTF) on rat retinal ganglion cells (RGCs) in the model. METHODS: The optic nerves of 12 Sprague-Dawley rats were crushed at 3 mm posterior to the eyeball for 1 minute using aneurysm clip (110 g). Two micrograms of CNTF in 2 micro liter of vehicle was injected intravitreally in one group (n=6) and 2 micro liter of PBS was injected in the control group (n=6) at 4, 7, and 10 days after the optic nerve injury. After 2 weeks, the retrograde labeling of the RGCs was done by the dextran tetramethylrhodamine. Twenty-four hours after the labeling, the retina was wholly mounted and the labeled RGCs were counted under the fluorescence microscope. RESULTS: The death of RGCs in this model began at 1 week and continued for 3 weeks. The number of labeled RGCs in CNTF-injected group (510+/-139/mm2) were significantly higher than that in control group (345+/-87/mm2)(p<0.05). CONCLUSIONS: The optic nerve crush injury model was established by use of aneurysm clip. In this model, the intravitreally injected CNTF had a neuroprotective effect on the rat RGCs.

Biochemical characterizations reveal different properties between CDK4/cyclin D1 and CDK2/cyclin A

CDK2 and CDK4 known promoter of cell cycling catalyze phosphorylation of RB protein. Enzyme specificity between two CDKs that work at a different cell cycle phase is not clearly understood. In order to define kinase properties of CDK2 and CDK4 in complex with cycline A or cycline D1 in relation to their respective role in cell cycling regulation, we examined enzymatic properties of both CDK4/cycline D1 and CDK2/cycline A in vitro. Association constant, Km for ATP in CDK4/cyclin D1 was found as 418 micrometer, a value unusually high whereas CDK2/cyclin A was 23 micrometer, a value close to most of other regulatory protein kinases. Turnover value for both CDK4/cyclin D1 and CDK2/cyclin A were estimated as 3.4 and 3.9 min(-1)respectively. Kinetic efficiency estimation indicates far over one order magnitude less efficiency for CDK4/cyclin D1 than the value of CDK2/cycline A (9.3 pM(-1)min(-1)and 170 pM(-1)min(-1)respectively). In addition, inhibition of cellular CDK4 caused increase of cellular levels of ATP, even though inhibition of CDK2 did not change it noticeably. These data suggest cellular CDK4/cyclin D1 activity is tightly associated with cellular ATP concentration. Also, analysis of phosphorylated serine/threonine sites on RB catalyzed by CDK4/cyclin D1 and CDK2/cyclin A showed significant differences in their preference of phosphorylation sites in RB C-terminal domain. Since RB is known to regulate various cellular proteins by binding and this binding is controlled by its phosphorylation, these data shown here clearly indicate significant difference in their biochemical properties between CDK4/cyclin D1 and CDK2/cyclin A affecting regulation of cellular RB function.

Localized Nerve Fiber Layer Defects with Normal Intraocular Pressure and Normal Visual Field

PURPOSE: To compare the features of localized nerve fiber layer (NFL) defects between with normal intraocular pressure and normal visual field (Group A) and with early visual field defect in normal-tension glaucoma (Group B). METHODS: This was a retrospective, nonrandomized clinical study in which thirty-two eyes of each group were enrolled. On the NFL photograph, proximity of defect to the fovea (angle alpha) and sum of angular widths of defects (angle beta) were determined. Angle alpha, angle beta and locations of the NFL defect were compared between two groups. The relationship between age and angle alpha and between age and angle beta were examined. Chi square test, student t-test and linear regression analysis were used for statistical analysis. RESULTS: Angle alpha of Group A was larger (68.5 +/- 20.4 degrees) than that of Group B (46.0 +/- 17.1 degrees), and angle beta of Group A was smaller (6.9 +/- 7.6 degrees) than that of Group B (28.0 +/- 21.0 degrees) (p<.05). Angle alpha of Group A decreased as age increased (p<.05), while there was no relationship between age and angle alpha in Group B. Most of NFL defects of Group A were distributed over superior retina but NFL defects of Group B were evenly distributed over superior and inferior retina. CONCLUSIONS: The feature of NFL defect with normal intraocular pressure and normal visual field was different from that of early normal-tension glaucoma. And that cannot be managed as preperimetric stage of normal-tension glaucoma.

Factors Associated with Progression of Visual Field Defect in Normal Tension Glaucoma

PURPOSE: To evaluate the risk factors associated with progression of visual field defect in patients with normal-tension glaucoma (NTG). METHODS: We reviewed medical records of 61 patients who were diagnosed as NTG and followed for more than 2 years. Age, sex, family history of glaucoma, migraine, hypertension, diabetes mellitus, refractive error, baseline intraocular pressure (IOP), disc hemorrhage, topographic data of optic disc, MD (mean deviation), and CPSD (corrected pattern standard deviation) of visual field test were analyzed. Progression of visual field was determined by Change Probability Analysis of Humphrey Field Analyzer. RESULTS: During an average follow-up of 42.5 months, 11 eyes of 61 eyes (18%) showed progression of visual field defect. Higher baseline IOP influenced significantly on the progression of visual field defect in NTG patients (Cox regression analysis, p<0.05). CONCLUSIONS: The higher the baseline IOP, the higher the probability of visual field progression.