Ching-Long Chen

Immediate Pars Plana Vitrectomy Improves Outcome in Retained Intravitreal Lens Fragments after Phacoemulsification

Purpose: To investigate the clinical features, visual acuity outcomes and the most appropriate intervention time in patients with retained lens fragments managed by pars plana vitrectomy. Methods: This was a retrospective review of the records of 78 patients who underwent pars plana vitrectomy for retained lens fragments at the Tri-Service General Hospital from January 1, 2000, to December 31, 2006. Results: The mean age of the patients was 70 years (range, 24–92 years). There were 40 men (51%) and 38 women (49%). The mean follow-up period after surgery was 13.8 months. Forty-five patients (58%) had vitrectomy within 1 day of phacoemulsification (group A), 22 (28%) within 1 week (group B) and 11 (14%) after more than 1 week (group C). No patients in group A developed complications, and 76% achieved a final visual acuity of 6/12 or better. In group B, all patients had elevated intraocular pressure, and 45% achieved a final visual acuity of 6/12 or better. In group C, all patients presented with corneal edema, moderate or severe uveitis, and elevated intraocular pressure. Of these patients, 27% had cystoid macular edema, 36% developed retinal detachment, and 27% had a final visual acuity of 6/12 or better. Conclusion: Pars plana vitrectomy performed immediately after cataract surgery for retained lens fragments is a viable option and may achieve a better visual outcome, with reduced risk of secondary glaucoma, retinal detachment or cystoid macular edema.

Glucosamine Modulates TNF-α–Induced ICAM-1 Expression and Function Through O-Linked and N-Linked Glycosylation in Human Retinal Pigment Epithelial Cells

PURPOSE The purpose of this article was to investigate the effects of glucosamine (GlcN) on the TNF-α-induced expression of intercellular adhesion molecule 1 (ICAM-1) and the function of ICAM-1 in ARPE-19 cells in vitro. METHODS We quantified protein levels of TNF-α-induced ICAM-1 in ARPE-19 cells with Western blotting. The effects of GlcN on O-linked glycosylation, and therefore on ICAM-1 expression, were compared after the addition of alloxan, an inhibitor of O-linked N-acetylglucosamine transferase (OGT), or O-(2-acetamido-2-deoxy-d-glucopyranosylidene)amino-N-phenylcarbamate (PUGNAc), an inhibitor of N-acetylglucosaminidase (O-GlcNAcase [OGA]), or after OGT gene overexpression. The effect of GlcN on the N-linked glycosylation of ICAM-1 was evaluated by the change in its molecular mass on Western blotting. The effect of O-linked glycosylation on the nuclear factor κB (NF-κB) signaling pathway was examined using an NF-κB reporter gene assay. The effect of GlcN on ICAM-1 adhesion activity was examined using an ICAM-1 adhesion assay. RESULTS GlcN, PUGNAc, and OGT overexpression inhibited TNF-α-induced ICAM-1 expression and NF-κB activity in ARPE-19 cells. Alloxan increased ICAM-1 expression and NF-κB activity in TNF-α-induced ARPE-19 cells. GlcN and tunicamycin reduced the molecular mass of TNF-α-induced ICAM-1 in ARPE-19 cells. The proteasome inhibitor MG-132 suppressed the GlcN-induced reduction in the molecular mass of TNF-α-induced ICAM-1. GlcN also attenuated the adhesion activity of TNF-α-induced ICAM-1. CONCLUSIONS GlcN inhibits ICAM-1 expression and functions by modulating the O-linked glycosylation of factors involved in NF-κB signaling and by reducing the N-linked glycosylation of TNF-α-induced ICAM-1 in ARPE-19 cells. These effects may contribute to the GlcN-mediated anti-inflammatory effects in the eye.

Protective Effects of Glucosamine on Oxidative-Stress and Ischemia/Reperfusion-Induced Retinal Injury

PURPOSE To investigate the protective effects of glucosamine (GlcN) using oxidative stress and rat models of ischemia-reperfusion (I/R) injury and to determine the antiapoptotic and anti-inflammatory mechanisms of GlcN treatment. METHODS We determined the effects of GlcN and the levels of O-linked N-acetylglucosamine (O-GlcNAc) in in vitro retinal ganglion cells (RGCs) treated with or without H₂O₂. The survival and apoptosis rates of RGCs were compared after the addition of GlcN, glucose, or O-(2-acetamido-2-deoxy-Dglucopyranosylidene) amino-N-phenylcarbamate (PUGNAc). Retinal I/R injury was induced in Sprague-Dawley rats by elevating the IOP to 110 mm Hg for 60 minutes. An intraperitoneal injection of GlcN (1000 mg/kg) or normal saline was administered in the different groups, including a control group, a GlcN group, an I/R group, a GlcN+I/R group (1000 mg/kg GlcN 24 hours before I/R injury), and an I/R+GlcN group (7-day period of 1000 mg/kg GlcN 24 hours after I/R injury). The rats were killed 7 days after the I/R injury, and the retinas were collected from each rat for thickness measurements. Quantitative analysis of RGC survival was further determined using labeling with FluoroGold. RESULTS The GlcN increased levels of O-GlcNAc in a dose-dependent manner in the RGCs treated with or without H₂O₂. The GlcN resulted in increased cell survival and reduced apoptosis in the RGCs under oxidative stress conditions. In the rat model of I/R injury, GlcN significantly protected against I/R-induced retinal thinning and suppressed the I/R-induced reductions in a- and b-wave amplitudes of the ERG. In terms of RGC survival, significant incremental density of RGCs was found in the I/R+GlcN group compared with the I/R group. Notably, the use of GlcN in the rat retina decreased apoptosis and the formation of reactive oxygen species (ROS) after I/R injury. We also found that mitogen-activated protein kinase signal pathways played a critical role in the GlcN-mediated attenuation of ROS-induced damage in vitro and I/R injury in vivo. CONCLUSIONS Glucosamine treatment provides multiple levels of retinal protection, including antiapoptotic, anti-inflammatory, and antioxidative benefits. More research on the role of GlcN as a potential agent for the prevention and treatment of glaucoma is warranted.

Trabeculectomy in patients with primary angle-closure glaucoma.

PurposeTo analyze the results of trabeculectomy in patients with primary angle-closure glaucoma. MethodsA retrospective and noncomparative case series analysis was performed on data from Taiwan, from 2001 to 2004. The outcomes of trabeculectomy in eyes with acute primary angle-closure glaucoma attack (AACG) and those with chronic primary angle-closure glaucoma (CACG) were assessed in terms of final intraocular pressure (IOP), changes to visual acuity, and the incidence of complications. ResultsA total of 52 eyes of 52 patients, 15 patients in AACG group and 37 patients in CACG group, were reviewed. The mean follow-up period was 32 months (range, 26-42 mo). In terms of no visual acuity change after surgery, there were significant differences between the CACG and AACG groups (P=0.02, Fisher exact test). In terms of final IOP control, trabeculectomy outcome was significantly worse in patients in the AACG group than those in the CACG group (P<0.01, Fisher exact test). Moreover, the complication of bleb encapsulation appeared more frequently in the AACG group than in the CACG group (P=0.02, Fisher exact test). ConclusionsCompared with CACG, trabeculectomy may not be as good for patients of AACG, because it may lead to worsened visual acuity; it also seems to present a greater failure rate, more complications, and fewer cases of surgical survival.

Bevacizumab modulates epithelial‐to‐mesenchymal transition in the retinal pigment epithelial cells via connective tissue growth factor up‐regulation

Purpose:  To investigate the effect of bevacizumab treatment on connective tissue growth factor (CTGF) expression and the induction of epithelial‐to‐mesenchymal transition in ARPE‐19 cells and human donor retinal pigment epithelium (HRPE) cells in vitro.

A Rare Case of Conjunctival Myxoma and a Review of the Literature

Background: To report on an 11-year-old boy with a painless slow-growing temporal bulbar conjunctival mass of his left eye. Methods: A case report and review of the literature. Results: An 11-year-old boy presented with a painless slow-growing mass in the temporal bulbar conjunctiva of his left eye, which had been noted for 1 year. After ophthalmic and systemic evaluations, the clinical differential diagnosis at the time included amelanotic naevus, amelanotic melanoma, myxoma, fibrous histiocytoma, reactive lymphoid hyperplasia and lipoma. This lesion was excised under local anaesthesia. From the histopathological features, conjunctival myxoma was confirmed. After 12 months, the patient remained healthy, with no recurrence or metastasis of the conjunctival lesion or evidence of a systemic abnormality. Conclusion: We report this case to emphasize that conjunctival myxoma can appear as a well-circumscribed, translucent, yellow-pink conjunctival mass in teenage patients. Successful healing is usually achieved by complete surgical resection. Cardiac, endocrine, and family screening is required to reduce the risk of morbidity and mortality.

Acute corneal hydrops with perforation after LASIK-associated keratectasia

Herein a case of acute corneal hydrops with perforation in keratectasia 9 years after bilateral laser in situ keratomileusis is presented. A 27‐year‐old man presented with right eye sudden loss of vision. Right eye best‐corrected visual acuity was counting fingers. Left eye best‐corrected visual acuity was 6/9. Right eye slit‐lamp examination revealed diffuse corneal oedema with central epithelial cystic change. The interface between the flap and residual stroma was open and filled with fluid. This separation extended nearly to the flap margin. Shallow anterior chamber and aqueous leakage were noted the following day. An emergency penetrating keratoplasty was performed to the right eye. Histopathology of corneal button revealed reactive keratocytes with irregular, wrinkled collagen formation over ablated stroma. Marked stromal oedema was observed. Twelve months after corneal transplantation, vision improved to 6/6 with correction in the right eye.

Silibinin inhibits myofibroblast transdifferentiation in human tenon fibroblasts and reduces fibrosis in a rabbit trabeculectomy model.

Purpose:  To investigate the effect of silibinin in myofibroblast transdifferentiation and in animal trabeculectomy models.

Silibinin Inhibits ICAM-1 Expression via Regulation of N-Linked and O-Linked Glycosylation in ARPE-19 Cells

To evaluate the effects of silibinin on intercellular adhesion molecule-1 (ICAM-1) expression, we used ARPE-19 cells as a model in which tumor necrosis factor (TNF-α) and interferon (IFN-γ) enhanced ICAM-1 expression. This upregulation was inhibited by silibinin. In an adherence assay using ARPE-19 and THP-1 cells, silibinin inhibited the cell adhesion function of ICAM-1. The inhibitory effects of silibinin on ICAM-1 expression were mediated via the blockage of nuclear translocation of p65 proteins in TNF-α and phosphorylation of STAT1 in IFN-γ-stimulated cells. In addition, silibinin altered the degree of N-linked glycosylation posttranslationally in ARPE-19 cells by significantly enhancing MGAT3 gene expression. Silibinin can increase the O-GlcNAc levels of glycoproteins in ARPE-19 cells. In a reporter gene assay, PUGNAc, which can also increase O-GlcNAc levels, inhibited NF-κB reporter activity in TNF-α-induced ARPE-19 cells and this process was augmented by silibinin treatment. Overexpression of OGT gene was associated with reduced TNF-α-induced ICAM-1 levels, which is consistent with that induced by silibinin treatment. Taken together, silibinin inhibits ICAM-1 expression and its function through altered O-linked glycosylation in NF-κB and STAT1 signaling pathways and decreases the N-linked glycosylation of ICAM-1 transmembrane protein in proinflammatory cytokine-stimulated ARPE-19 cells.

Infectious crystalline keratopathy caused by Serratia marcescens.

Purpose: To report the case of a 70-year-old woman with Serratia infectious crystalline keratopathy. Methods: Case report. Results: This is a report of a 70-year-old woman with a history of chronic open-angle glaucoma and trachoma with lagophthalmos, entropion, and trichiasis in both eyes who developed crystalline keratopathy after penetrating keratoplasty and cataract extraction in the right eye followed up with treatment with long-term topical steroids. Ten months after the initial penetrating keratoplasty and cataract extraction, the patient had decreased visual acuity, intense pain, and tearing in the right eye. Corneal cultures showed Serratia marcescens. Topical steroids were discontinued, and treatment with tobramycin and vancomycin ophthalmic solution every hour was initiated. Despite 1 week of aggressive therapy, there was an increase in corneal infiltrate, epithelial defects, and melting, which eventually involved the peripheral recipient cornea. Therapeutic penetrating keratoplasty, debridement of the peripheral cornea, and amniotic membrane transplantation were performed. Antibiotic agents were used postoperatively. There has been no evidence of recurrent infection. The best-corrected visual acuity improved to 6/15 at the 6-month follow-up period after the second intervention. Conclusions: S. marcescens may cause infectious crystalline keratopathy after penetrating keratoplasty in patients treated with long-term topical steroids. Therapeutic penetrating keratoplasty, surgical debridement, and amniotic membrane transplantation may be necessary when the clinical response to intensive medical treatment is inadequate.