Biomedical subjects

Jae Kyoun Ahn

Publications and source records attributed to Jae Kyoun Ahn.

10 recordsLinked to original sources

PubMed2006

Phacotrabeculectomy with mitomycin C in patients with uveitis.

PURPOSE: To evaluate the safety and efficacy of combined phacoemulsification, intraocular lens implantation, and trabeculectomy with mitomycin C for the management of uveitic complications. DESIGN: Retrospective case-control study. METHODS: We conducted a retrospective review of the records of 23 consecutive eyes with chronic noninfectious uveitis (uveitic group) and 43 nonuveitic eyes (control group) that had received primary phacotrabeculectomy. Mitomycin C was used in all the uveitic eyes. Considering the high preoperative intraocular pressure (IOP) of the uveitic group, nonuveitic eyes that had a preoperative IOP of >or=20 mm Hg or that had been given two or more medications were included in the control group. All patients were followed for at least one year. The main outcome measures were postoperative vision, IOP control, complications, and acute uveitis relapse rates. RESULTS: Visual outcome of the uveitic group was similar to the control group. In the uveitic group, the success rate of IOP control (91.3% at one year, 84.8% at two years) was favorable but was significantly lower than in the control group (P = .0423). Complications were comparable between the groups. Primary surgical failure in the uveitic group was associated with the postoperative acute uveitis attack. In the uveitic group, the acute uveitis attack rate showed no change after surgery (P = .283). CONCLUSION: With adequate inflammation suppression, phacotrabeculectomy with mitomycin C is an effective and safe therapeutic option for the management of secondary cataract and glaucoma in uveitic eyes. A lower surgical success rate of the uveitic group might be attributable to the postoperative inflammation recurrence.

Acute Disease↗

PubMed2006

Intraocular cytokine environment in active Behçet uveitis.

PURPOSE: To determine cytokine profiles in aqueous humor and peripheral blood from patients with Behçet uveitis. DESIGN: Prospective, experimental, and case-control study. METHODS: Aqueous humor and peripheral blood samples from 24 patients with Behçet uveitis, 28 patients with other causes of endogenous uveitis, and 20 healthy subjects after uncomplicated cataract surgery were obtained. Cytokines (interferon gamma (IFN-gamma), interleukin [IL]-2, IL-4, IL-10, IL-12, IL-15, and tumor necrosis factor alpha (TNF-alpha)) were measured by enzyme-linked immunosorbent assay and compared between the uveitis groups. RESULTS: Aqueous interferon gamma (IFN-gamma) levels were higher in patients with Behçet uveitis in contrast to higher concentrations of IL-4 in patients without Behçet uveitis. Aqueous levels of tumor necrosis factor alpha (TNF-alpha) were higher in patients with Behçet uveitis than in patients without Behçet uveitis. Aqueous and serum IL-10 were detected in all patients without Behçet uveitis, but were below detection limits in all patients with Behçet uveitis. Furthermore, IL-15 was exclusively increased in the aqueous humor of Behçet uveitis. The aqueous IL-2 or IL-12 levels were similar regardless of the presence of Behçet uveitis. CONCLUSIONS: Our results showed that an extreme Th1 polarization, a high proinflammatory condition, a low immunosuppressive status, and the presence of natural killer (NK) or CD8+ T cell-activating cytokine were unique features in aqueous humor with Behçet uveitis, suggesting that different immunopathogenic mechanisms may be involved in the ongoing intraocular inflammation of Behçet uveitis.

Adult↗

PubMed2006

Combined low dose cyclosporine and prednisone down-regulate natural killer cell-like effector functions of CD8brightCD56+ T cells in patients with active Behçet uveitis.

PURPOSE: To investigate the changes of effector-related phenotypic markers and the natural killer (NK)-like effector functions of CD8(bright)CD56+ T cells in patients with Behçet uveitis after combined cyclosporine and prednisone (Cs/Pd) treatment. METHODS: Ten patients with active Behçet panuveitis and 10 healthy controls were prospectively recruited in this study. The effector-related surface markers (CD27, CD62L, CD11b, HLA-DR, CD94, NKG2D), chemokine receptors (CXCR1, CXCR3, CCR4, CCR5), and intracellular perforin of circulating CD8(bright)CD56+ T cells were determined by flow cytometric analysis before and after two months' treatment. NK-like cytotoxicity of ex vivo CD8(bright)CD56+ T cells against K562 was measured by standard 51Cr release assay. RESULTS: The expression levels of effector-related molecules on CD8(bright)CD56+ T cells normalized after treatment. The expression levels of CXCR1 and CCR5 were down-regulated on CD8(bright)CD56+ T cells after treatment. The amounts of preformed intracellular perforin of CD8(bright)CD56+ T cells were reduced to the normal levels. Furthermore, the NK-like cytolytic capacities of CD8(bright)CD56+ T cells were decreased after treatment. CONCLUSIONS: Our results suggest that the combined Cs/Pd treatments in active Behçet uveitis may downregulate the NK-like effector functions of CD8(bright)CD56+ T cells.

Adult↗

PubMed2005

CD8brightCD56+ T cells are cytotoxic effectors in patients with active Behcet's uveitis.

Behçet's uveitis, characterized by chronic recurrent uveitis and obliterating retinal vasculitis, frequently causes bilateral blindness. Intraocular infiltration of TCRalphabeta+CD8brightCD56+ cells was a distinct feature in Behçet's uveitis. However, phenotypic natures and effector functions of the cells have remained elusive. This study was conducted to determine phenotypic and functional characteristics and cytotoxic mechanisms of CD8brightCD56+ T cells in Behçet's uveitis. CD11b+CD27-CD62L- phenotypes of CD8brightCD56+ T cells were increased in patients with active Behçet's uveitis compared with inactive Behcet's patients and normal controls. Interestingly, CD45RAdimCD45RO- phenotypes were expanded, and CD94 expression was markedly up-regulated in contrast to the down-regulation of NKG2D. Furthermore, these subsets were polarized to produce IFN-gamma and contained high amounts of preformed intracellular perforin while exclusively expressing surface FasL upon PI stimulation. Moreover, the cytolytic functions of freshly isolated CD8brightCD56+ T cells were up-regulated against both K562 (NK-sensitive) and Raji (NK-resistant) cells, which were effectively inhibited by perforin inhibitor (concanamycin A). Their cytolytic activity against HUVECs was also increased and was effectively suppressed by Fas ligand inhibitor (brefeldin A) and partly by perforin inhibitor. Furthermore, cytolytic functions of PMA and ionomycin-stimulated CD8brightCD56+ T cells against HUVECs were greatly enhanced, by pretreatment of recombinant human IFN-gamma on HUVECs. Therefore, CD8brightCD56+ T cells in Behçet's uveitis are characterized by cytotoxic effector phenotypes with functional NK receptors and function as strong cytotoxic effectors through both Fas ligand-dependent and perforin-dependent pathways.

Adult↗

PubMed2005

Anatomical and functional characteristics in atrophic maculopathy associated with spinocerebellar ataxia type 7.

PURPOSE: To assess the anatomic and functional characteristics in a Korean family with spinocerebellar ataxia type 7-associated atrophic maculopathy. DESIGN: Observational case report. METHODS: Three patients in a family underwent funduscopic examination, fluorescein angiogram, full-field electroretinogram (ERG), electro-oculogram, and optical coherence tomography (OCT). Macular functions were assessed using multifocal ERG and scanning laser ophthalmoscope (SLO) microperimetry. RESULTS: Both eyes showed bull's eye configuration and cone-rod dystrophy phenotype. OCT revealed that retinal thinning extended outside the visibly atrophic lesions. Multifocal ERG demonstrated that amplitudes from the six ring segments were reduced in a centrifugal pattern. SLO microperimetry showed that fixations were unstable and shifted superior to the atrophic lesions. The areas of functional deficits were greater than those of anatomic deficits. CONCLUSIONS: Macular functions were severely depressed in atrophic maculopathy associated with spinocerebellar ataxia type 7 in both the visibly atrophic areas and the areas without visible atrophy in a centrifugal pattern.

Adult↗

PubMed2005

Vitrectomy for persistent panuveitis in Behçet's disease.

PURPOSE: To determine whether vitrectomy is safe and effective for the management of vitreoretinal complications in Behçet's patients with persistent panuveitis. METHODS: Patients who had undergone therapeutic vitrectomy for Behçet's panuveitis were reviewed retrospectively. Those patients who had shown persistent uveitis despite maximum medical therapy were included. Surgical outcomes were measured by an improvement in vision of 0.3 logarithm of minimum angle of resolution, acute relapse rates, and postoperative complications. RESULTS: Twenty-one patients with a mean postoperative follow-up of 30 months were identified. For almost all patients visual acuity and inflammatory control were significantly improved after vitrectomy. However, patients with optic disc neovascularization (NVD) showed no improvement in their vision or inflammatory control. The postoperative rise of intraocular pressure was frequently associated with intravitreal triamcinolone acetonide injections. CONCLUSIONS: Our study suggests that vitrectomy may be both safe and effective for the management of vitreoretinal complications in Behçet's patients with persistent uveitis. Patients with NVD, however, may have poor outcomes.

Adult↗

PubMed2005

Down-regulation of IFN-gamma-producing CD56+ T cells after combined low-dose cyclosporine/prednisone treatment in patients with Behçet's uveitis.

PURPOSE: To investigate the effects of combined low-dose cyclosporine and prednisone (Cs/Pd) treatment on circulating CD56+ T cells in patients with Behçet's uveitis. METHODS: Ten patients with Behçet's uveitis and 10 healthy control subjects were prospectively recruited. The patients were treated with Cs/Pd for 2 months. Phenotypic and functional changes in circulating CD56+ T cells were assayed before and after treatment. CD56+ T-cell subsets were determined by flow cytometric analysis with monoclonal antibodies for CD3, CD4, CD8, CD56, pan gammadelta TCR, and Valpha24. The absolute numbers of cells in the lymphocyte subsets were calculated. Cytokine (IFN-gamma, IL-4, and IL-10) expressions were measured by ELISA and by intracellular cytokine staining. RESULTS: The proportions of CD56+ T cells, specifically CD8highCD56+ and CD56+gammadelta T-cell subsets, were significantly higher in active Behçet's uveitis but normalized after treatment, whereas the total T-lymphocyte count and the absolute numbers of CD56- T cells were unaffected by treatment. The levels of IFN-gamma and IL-4 were elevated in aqueous humor and serum in Behçet's uveitis (P < 0.001), whereas IL-10 was not detected. After treatment, serum IL-4 levels markedly increased (P < 0.001), and IFN-gamma production by circulating CD56+ T cells was then suppressed. IL-4 and -10 production by CD56+ T cells was increased by treatment, but in contrast, minimal changes were found in CD56- T cells. CONCLUSIONS: The results imply that Cs/Pd treatment for Behçet's uveitis selectively affects the population of and the cytokine expression in CD56+ T cells, but without significant changes in CD56- T cells, and that IFN-gamma-producing CD56+ T cells are the central pathogenic immune cells in Behçet's uveitis.

Adult↗

PubMed2004

Correlation between a disc hemorrhage and peripapillary atrophy in glaucoma patients with a unilateral disc hemorrhage.

PURPOSE: To investigate the correlation between a disc hemorrhage and peripapillary atrophy in glaucoma patients with a unilateral disc hemorrhage. METHODS: The 44 glaucoma patients (7 with primary open-angle glaucoma and 37 with normal-tension glaucoma) with a unilateral disc hemorrhage from June 1997 to November 2002 were selected randomly and included sequentially. The topographic measurements were performed using Heidelberg Retina Tomograph (HRT) within 3 months of detecting the disc hemorrhage. The zone beta parameters of the peripapillary atrophy were analyzed by the Atrophy Zone Analysis software. The intraocular pressure, refractive error, visual field parameters, and optic disc parameters were compared between both eyes. Univariate and multivariate regression analysis were performed. RESULTS: The area, angular and radial extent of the zone beta, and the ratio of the zone beta area to the disc area were significantly greater in the hemorrhagic eyes than in the contralateral eyes (P < 0.001). The prevalence of peripapillary atrophy was significantly higher in the hemorrhagic eyes (84%) than in the contralateral eyes (66%) (P = 0.034, chi2 test). The rim area and the rim volume of the hemorrhagic eyes were significantly smaller than those of the contralateral eyes (P = 0.02, < 0.001, respectively). In multivariate regression analysis, the peripapillary atrophy area was the independent significant factor associated with disc hemorrhage (P = 0.03, Odds Ratio = 1.51). The refractive error, intraocular pressure, Mean Deviation (MD), and Corrected Pattern Standard Deviation (CPSD) of the visual fields in both eyes were similar. CONCLUSION: The area and extent of the peripapillary atrophy was significantly greater and more prevalent in the eyes with a disc hemorrhage than in the contralateral control eyes. Peripapillary atrophy is closely associated with a disc hemorrhage in glaucoma patients irrespective of small neuroretinal rim area and volume.

Aged↗

PubMed2003

Transscleral fixation of a foldable intraocular lens in aphakic vitrectomized eyes.

PURPOSE: To evaluate the clinical outcomes of transscleral fixation of a foldable intraocular lens (IOL) in eyes that had pars plana lensectomy combined with pars plana vitrectomy for severe vitreoretinal disease. SETTING: Seoul National University Hospital, Seoul, Korea. METHODS: The medical records of 21 patients who had a transscleral fixation of a foldable IOL after previous vitrectomy combined with lensectomy for severe posterior segment pathology were reviewed. The underlying vitreoretinal diseases were complicated proliferative diabetic retinopathy (n = 9), proliferative vitreoretinopathy (n = 5), traumatic retinal detachment (n = 3), intraocular foreign body (n = 2), and uveitic retinal detachment (n = 2). The postoperative best corrected visual acuity (BCVA) was compared with the preoperative BCVA. Autorefractometry and keratometry measurements and central endothelial cell counts were evaluated 1 day preoperatively and 6 months postoperatively. RESULTS: The mean age of the patients was 54.5 years. The preoperative aphakic period ranged from 2 to 22 months. The visual acuity reached the preoperative BCVA by 2 months after surgery and was better than the preoperative BCVA at 6 months (P =.006) and at the final visit (P =.003). Six months postoperatively, the mean myopic shift by cycloplegic autorefractometry was -1.0 diopter (D) and the mean scalar shift in surgically induced keratometric cylinder, 1.0 D. The mean central corneal endothelial loss at 6 months was 6.7% (range 2.4% to 22.2%). The only vitreoretinal complications were a transient vitreous hemorrhage and a reopened macular hole that was reattached after fluid-gas exchange. CONCLUSION: Transscleral fixation of a foldable IOL was safe and led to favorable visual outcomes in aphakic vitrectomized eyes with previous severe vitreoretinal disease.

Adult↗

PubMed2002

Morphometric change analysis of the optic nerve head in unilateral disk hemorrhage cases.

PURPOSE: To measure the changes in optic disk morphology after unilateral disk hemorrhage and to compare the changes between eyes. DESIGN: Observational case series. METHODS: Ten glaucoma patients who had a unilateral disk hemorrhage were enrolled. The baseline measurements obtained by Heidelberg Retina Tomograph (HRT) were performed on both eyes when a disk hemorrhage was detected, and the second measurements were done after an average of 32 +/- 19 months. The amount of change and the percent change in the HRT parameters from the baseline measurements of the hemorrhagic eyes were compared with those of the contralateral nonhemorrhagic eyes. RESULTS: The reduction in the neuroretinal rim area and the decrease in volume were significantly greater in the octant with the disk hemorrhage than measured in the contralateral eyes (P =.002, Wilcoxon signed rank test). CONCLUSIONS: This study demonstrated quantitatively that the progression of optic disk damage in glaucoma is faster in eyes with disk hemorrhage than in eyes without disk hemorrhage.

Disease Progression↗