Biomedical subjects

Wan-Chen Ku

Publications and source records attributed to Wan-Chen Ku.

8 recordsLinked to original sources

PubMed2006

Interleukin-1 receptor antagonist (IL-1RA) prevents apoptosis in ex vivo expansion of human limbal epithelial cells cultivated on human amniotic membrane.

Stem cells of the corneal epithelium have been found to be located exclusively at the anatomical junction between the cornea and the conjunctiva, the limbus. Ex vivo expanded limbal epithelial cells on amniotic membrane (AM) are capable of restoring the corneal surface with limbal stem cell deficiency. Recent studies indicate that intact AM preserves the limbal epithelial phenotype and that distinct epithelial morphology is noted among various culture matrix. However, the factors in response to the interaction between limbal epithelial cells and AM were not well understood. Using Annexin V-fluorescein isothiocyanate staining, we found that human limbal epithelial cells expanded on intact human AM demonstrated fewer apoptotic cells as compared with those on plastic dishes. To identify the anti-apoptotic factors, we performed cDNA microarray analysis and showed that interleukin-1 receptor antagonist (IL-1RA) was overexpressed in cultures on intact AM, which was confirmed by reverse transcription-polymerase chain reaction (RT-PCR), real-time quantitative PCR (Q-PCR) and enzyme-linked immunosorbent assay. In addition, we also noted that the phenomenon of apoptosis detected in cultures on plastic dishes could be reversed by adding recombinant IL-1RA protein into the media, whereas apoptosis of limbal epithelial cells cultivated on intact AM could be induced by exogenous neutralizing IL-1RA neutralizing antibody. These results demonstrated that intact human AM may prevent cultured human limbal epithelial cells from undergoing apoptosis. IL-1RA might be a candidate mediator to exert as an anti-apoptotic molecule during the interaction between human limbal epithelial cells and intact human AM.

Adolescent↗

PubMed2005

Role of matrix metalloproteinase-9 in ex vivo expansion of human limbal epithelial cells cultured on human amniotic membrane.

PURPOSE: To investigate the expression and pivotal role of matrix metalloproteinase (MMP)-9 in the ex vivo expansion of human limbal explants with or without amniotic membrane (AM). METHODS: Corneoscleral buttons were cultured on intact, denuded AM or plastic dishes for 3 weeks. To determine the role of MMP-9 in cell migration, either the MMP inhibitor GM6001 or an MMP-9 antibody was used. Expression of MMP-9 was determined by gelatin zymography, reverse transcription-polymerase chain reaction, and immunohistochemical staining. RESULTS: The expression of MMP-9 in all culture conditions increased in a time-dependent manner. However, the active form of MMP-9 emerged only in cultures on both intact and denuded AM from the second week. The averaged corrected ratio of MMP-9 expression in cultures on intact AM versus those on denuded AM or plastic dishes was 2.76 +/- 0.69- or 4.25 +/- 0.30-fold, respectively, when total RNA was used as an internal control. MMP-9 transcripts were upregulated in cultures on intact AM compared with the other two culture conditions. Immunohistochemical staining demonstrated that the MMP-9 protein was located on the limbal epithelial cells. Upregulation of MMP-9 associated with cell migration was significantly attenuated by both GM6001 and MMP-9 antibody, consistent with the inhibition of MMP-9 activity, as determined by gelatin zymography. In contrast, the sizes of limbal outgrowth were not different between the control and MMP-9 antibody-treated plastic dishes. CONCLUSIONS: These results demonstrated that MMP-9 not only was upregulated, it was also involved in the outgrowth of limbal epithelial cells. These results suggest that cell-cell matrix interaction is involved in the expansion of limbal epithelial cells on intact AM, and MMP-9 may be a key element.

Adolescent↗

PubMed2005

Choroidal detachment after filtering surgery.

BACKGROUND: The purpose of this study is to report the treatment and outcome of eight cases of choroidal detachment, which occurred several days to many years after trabeculectomy. METHODS: This is a retrospective study of eight cases of choroidal detachment after trabeculectomy with or without cataract extraction reviewed at CGMH, Keelung, from 2002 to 2004. One eye with idiopathic scleromalacia with chronic uveitis and secondary glaucoma, five eyes with primary open angle glaucoma and two eyes with chronic angle closure glaucoma after trabeculectomy were reported. Six of the eight cases developed acute onset choroidal detachment within two weeks after surgery. The other two cases suffered from choroidal detachment many years after trabeculectomy for different reasons. Regarding the types of operation, combined glaucoma and cataract surgery was performed in five cases and intraoperative application of adjunctive mitomycin C was used in two cases. Decrease in vision acuity and varying degrees of eye pain with a flat or shallow chamber were noted in all cases. Associated hypotony was found in six of the eight cases. The treatment included topical cycloplegic corticosteroid and oral corticosteroid. RESULTS: Choroidal detachments were improved or complete resolution obtained after medical treatment for about three weeks to one month in all cases. But persistent poor control of intraocular pressure was found in two cases. Ultrasonography was used as a reliable tool to confirm the diagnosis and resolution of choroidal etachment in cases of blurred fundus examination and synechiae miotic pupil. CONCLUSIONS: Choroidal detachment is one of the complications after trabeculectomy. The diagnosis of choroidal detachment can be confirmed most reliably by ultrasonography. Medical therapy is effective for resolution.

Adult↗

PubMed2004

Efficacy and safety of phacoemulsification with intraocular lens implantation under topical anesthesia.

BACKGROUND: To eliminate complications of peribulbar and retrobulbar anesthesia and to achieve efficacy and safety for topical anesthesia with cataract surgery. METHODS: We performed clear corneal phacoemulsification with foldable intraocular lens (IOL) implantation under topical anesthesia using preservative-free 2% lidocaine drops, without intracameral anesthetic supplementation. The exclusion criteria were anxiety, small pupil, baseline endothelial count 1500 cells/mm2, uncontrolled glaucoma, other ocular entities affecting corneal endothelium, and allergy to the relevant medications. We used a specular microscope to evaluate the effect on the endothelium and employed a 10-point visual analog pain scale to assess the discomfort experienced during the operation. RESULTS: Totally, 29 eyes of 29 patients were enrolled in this series. The mean age was 71.5 +/- 8.5 years. Twenty-three of 29 (79.3%) cases achieved a best-corrected visual acuity (BCVA) equal to 20/40 or better at an interval of 3 months postoperatively. Most patients (86.5%) felt mild or no pain during surgery. Pre- and postoperative endothelial counts were 2072.6 +/- 104 and 1927.4 +/- 196 cell/mm2, respectively. One in 29 cases developed vitreous loss due to involuntary eye movements intraoperatively. CONCLUSIONS: Topical anesthesia with preservative-free 2% lidocaine drops is an effective and safe modality for clear corneal phacoemulsification with IOL implantation. On the other hand, for patients with small pupil or those who are anxious, the procedure may be time-consuming, and it is challenging for physicians to perform cataract surgery merely using topical anesthesia.

Aged↗

PubMed2003

Progression of diabetic retinopathy after phacoemulsification in diabetic patients: a three-year analysis.

BACKGROUND: This retrospective study was conducted to analyze the progression rates of diabetic retinopathy (DR) after phacoemulsification in diabetic patients and to determine whether phacoemulsification causes the progression of DR. METHODS: The medical charts of diabetic patients who had undergone cataract surgery using phacoemulsification techniques during a 3-year period and had completed 3 years of follow-up were retrospectively reviewed. Data were collected to evaluate the visual outcomes and progression of DR postoperatively. The retinopathy progression rates of operated and nonoperated eyes were compared. RESULTS: Thirty-seven diabetic patients were enrolled. Binocular cataract surgeries were performed in 14 patients. Monocular cataract surgeries were performed in the remaining 23 patients whose nonoperated fellow eyes served as the control group. The postoperative retinopathy progression rates of eyes with preoperative mild to moderate nonproliferative diabetic retinopathy (NPDR) were significantly greater than eyes without preoperative retinopathy whether at postoperative 1 year or postoperative 3 years. No statistical significance was found for the rate of retinopathy progression between operated and nonoperated eyes at 1 year and 3 years postoperatively. Of 51 operated eyes, 33 (64.7%) achieved an uncorrected visual acuity of 20/40 at 1 year postoperatively, and 47 (92.1%) had improvement of visual acuity of more than two lines. CONCLUSION: Uncomplicated phocoemulsificaton had no significant influence on the postoperative progression of DR. Patients with preoperative NPDR had greater chances to show postoperative retinopathy progression. The majority of diabetic patients who had no DR or had mild to moderate NPDR achieved visual improvement after phacoemulsification.

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PubMed2002

Cataract extraction in high myopic eyes.

BACKGROUND: According to the high prevalence of myopia in Taiwan, we analyze the adopted cataract extractions, identify predicting factors for postoperative vision, and to assess the incidence of retinal complications after Nd: YAG laser capsulotomy in high myopic eyes. METHODS: One hundred and twenty-five eyes, which the axial lengths were longer than 26 mm, following cataract extraction were enrolled. Surgeries adopted included phacoemulsification with intraocular lens implantation, extracapsular cataract extraction with intraocular lens implantation, phacoemulsification, and extracapsular cataract extraction. Logistic regression was utilized to assess predictive factors for postoperative vision. RESULTS: Postoperative vision of 41 eyes (32.8%) of the 125 high myopic eyes improved at least 4 lines of Snellen acuity. Thirty-two eyes (25.6%) achieved good postoperative vision (BCVA > or = 20/40), and 26 eyes (20.8%) demonstrated poor postoperative vision (BCVA < 20/200). Younger age and shorter axial length were appreciated for better visual outcome (p < 0.05). Nd: YAG laser capsulotomy is required for posterior capsular opacity. Three in 125 eyes (2.4%) developed retinal complications and 2 of them had retinal detachment subsequently within one month after Nd: YAG laser capsulotomy. CONCLUSION: Most high myopic patients achieved visual improvement after cataract surgeries. Age and axial length are the predictive factors in high myopic patients. It is crucial to examine retina prior to Nd: YAG laser capsulotomy to prevent retinal complication.

Adult↗

PubMed2002

Surgical removal of the internal limiting membrane for the treatment of a macular hole.

BACKGROUND: To evaluate the efficacy of internal limiting membrane (ILM) peeling in the treatment of a macular hole. METHODS: The ocular evaluation included Snellen visual acuity, a slit-lamp examination, indirect ophthalmoscopy, and contact lens biomicroscopy. The macular holes were confirmed using a Watzke-Allen slit beam test. Surgery consisted of a standard 3-port vitrectomy under local anesthesia. The vitreous was removed, and the macular ILM was peeled by creating a small opening and a tear in the ILM with a bent 22-gauge needle around the inner margin of the vascular arcade. The ILM flap was then grasped with end-gripping forceps, and a circular capsulorrhesis maneuver was initiated. Next, gas-fluid exchange and internal tamponade with 10% C3F8 were performed, followed by postoperative face-down positioning. RESULTS: Thirty-six eyes in 36 patients with idiopathic macular holes from stages 2 to 4 were included. The average follow-up time was 8.9 months. The holes were completely closed in 33 eyes (92%), and visual acuity was improved in 26 eyes (72%). Ten eyes were pseudophakic, 24 of the 26 phakic eyes had an increased density of the cataract after surgery, which was not detected in 2 cases. One of the patients had vitreous hemorrhage and hyphema; no retinal detachment or retinal tear was found in this study. CONCLUSION: Surgery for macular holes using ILM peeling has a high anatomical and functional success rate.

Adult↗

PubMedDate not supplied

Surgical management of scleral perforation after pterygium excision.

OBJECTIVE: Scleral perforation is a rare complication occurring after pterygium excision often leading to scleral ulceration and loss of vision. Our purpose is to evaluate the long-term effectiveness and safety of tenonplasty and amniotic membrane transplantation in the management of scleral perforation after pterygium excision. PATIENTS AND METHODS: We performed a retrospective study on patients with scleral perforation after pterygium excision that underwent tenonplasty and amniotic membrane transplantation at Chang Gung Memorial Hospital from 1997 to 1999 and followed up for at least 12 months postoperatively. RESULTS: There were 6 patients, 1 male and 5 females ranging in ages from 46 to 71 years (mean, 63.3). The interval between pterygium excisions to scleral perforation ranged from 3 to 20 years. There were no recurrences during the follow-up period of 12 to 24 months (average, 18.3 months). CONCLUSIONS: Tenonplasty and amniotic membrane transplantation appears to be a relatively simple, safe, and effective method for treating scleral perforation after pterygium excision.

Aged↗