Biomedical subjects

Eung Kweon Kim

Publications and source records attributed to Eung Kweon Kim.

At least 19 recordsLinked to original sources

PubMed2007

Development of a DNA chip for the diagnosis of the most common corneal dystrophies caused by mutations in the betaigh3 gene.

AIM: To develop a diagnostic DNA chip to detect mutations in the betaigh3 gene causing the most common corneal dystrophies (CDs). METHODS: Samples from 98 people, including patients with betaigh3-associated CDs (beta-aCDs), were examined. Specific primer and probe sets were designed to examine exons 4 and 12 of the betaigh3 gene, in order to identify mutant and wild-type alleles. Mutations were then identified by hybridisation signals of sequence-specific probes immobilised on the slide glass. RESULTS: Direct sequencing of exons 4 and 12 of the betaigh3 gene in the patients' genome showed that beta-aCDs could be mainly classified into five types: homozygotic Avellino corneal dystrophy (ACD), heterozygotic ACD, heterozygotic lattice CD I, heterozygotic Reis-Bucklers CD and heterozygotic granular CD. Blind tests were performed by applying the target DNA amplified from the genomic DNA isolated from the peripheral blood of the participants onto a DNA chip. The results obtained by DNA chip hybridisation matched well with the direct DNA sequencing results. CONCLUSIONS: The DNA chip developed in this study allowed successful detection of beta-aCDs with a sensitivity of 100%. Mutational analysis of exons 4 and 12 of the betaigh3 gene, which are the mutational hot spots causing beta-aCDs, can be successfully performed with the DNA chip. Thus, this DNA chip-based method should allow a convenient, yet highly accurate, diagnosis of beta-aCDs, and can be further applied to diagnose other types of CDs.

Base Sequence↗

PubMed2006

Impact of short-term exposure of commercial eyedrops preserved with benzalkonium chloride on precorneal mucin.

PURPOSE: The aim of this study is to investigate the short-term effects of benzalkonium chloride (BAC), a preservative used in many ophthalmic topical solutions, on precorneal mucin in humans. METHODS: Immortalized human corneal-limbal epithelial (HCLE) cells were exposed to eyedrops containing BAC solutions at 0.0025% and 0.01% concentrations for a period of 15 min. Human corneal epithelium was acquired with consent, as a byproduct of elective excimer photorefractive keratectomy procedures after application of Ocuflox eyedrops (0.3% ofloxacin with 0.0025% BAC) for 1 week before surgery. The relative expression of the MUC1 and MUC16 mucin gene was determined by conventional and real-time reverse transcription-polymerase chain reaction (RT-PCR). Monoclonal antibodies for MUC1 (HMFG-1) and MUC16 (OC125) were used in western blot analysis to detect MUC1 and MUC16. Human corneas exposed to 0.01% BAC solutions were examined by transmission electron microscopy. RESULTS: The expression of MUC1 and MUC16 gene transcripts was not changed after exposure to BAC in HCLE cells and human corneal epithelium. However, MUC1 and MUC16 were reduced after exposure to BAC in HCLE cells and human corneal epithelium. Transmission electron microscopy of the anterior corneal surface revealed fixation of the mucous layer after exposure to 0.01% BAC for 5 or 15 min; prolonged exposure (60 min) to 0.01% BAC destroys the mucous layer. CONCLUSIONS: This study demonstrates that short-term exposure to BAC can alter the precorneal mucin.

Antigens, Neoplasm↗

PubMed2006

Comparison of corneal nerve regeneration and sensitivity between LASIK and laser epithelial keratomileusis (LASEK).

PURPOSE: To compare changes in corneal nerve fibers and keratocyte density by confocal microscopy after laser-assisted in situ keratomileusis (LASIK) and laser epithelial keratomileusis (LASEK). DESIGN: Prospective, nonrandomized comparative clinical trial. METHODS: Fifty-six eyes of 28 patients who underwent LASIK and 52 eyes of 26 patients who underwent LASEK were included. Confocal microscopic data of the central cornea, corneal sensitivity, tear film breakup time, and Schirmer values were determined at three and six months after LASIK or LASEK treatment. RESULTS: In the LASIK group, corneal sensitivity was reduced from preoperative levels at six months after surgery. In the LASEK group, however, there was no difference between baseline and six-month postoperative values. The number of subbasal nerve fibers and the keratocyte density were also different in the LASIK and LASEK groups. The regeneration of corneal nerves correlated strongly with the recovery of corneal sensation and keratocyte density in both groups, whereas the tear film breakup time, Schirmer values, and epithelial thickness did not correlate with corneal nerve regeneration in either group. CONCLUSIONS: The greater decrease in the number of subbasal nerve fibers in the LASIK group compared with the LASEK group may relate to the greater decrease in corneal sensitivity. The pattern of corneal nerve regeneration and the recovery of corneal sensation after LASEK did not differ greatly from that after photorefractive keratectomy in previous studies.

Adult↗

PubMed2006

Amniotic membrane as a biologic pressure patch for treating epithelial ingrowth under a damaged laser in situ keratomileusis flap.

We present 2 patients who had epithelial ingrowth after intraoperative laser in situ keratomileusis (LASIK) complications that created defects in the flap near the visual axis. As an adjuvant to removing the epithelium, an amniotic membrane patch was sutured tightly to the episclera so that it covered the entire cornea. The amniotic membrane overlay was left in place for about 1 week. There was no evidence of recurrent epithelial ingrowth after a minimum of 4 months. Use of an amniotic membrane overlay can be an effective adjuvant therapy to secure a LASIK flap when direct suturing would threaten the visual axis.

Adult↗

PubMed2006

Comparison of higher-order aberrations after wavefront-guided laser in situ keratomileusis and laser-assisted subepithelial keratectomy.

PURPOSE: To compare the higher-order aberrations (HOAs) in 70 eyes (38 patients) that had wavefront-guided laser in situ keratomileusis (LASIK) with those in 70 eyes (40 patients) that had wavefront-guided laser-assisted subepithelial keratectomy (LASEK) for the treatment of myopia. SETTING: Department of Ophthalmology, Yonsei University College of Medicine, Myongdong Bal-geun sesang Eye Clinic, and Seran Eye Center, Seoul, Korea. METHODS: In a prospective study, 140 consecutive eyes of 78 patients were treated with wavefront-guided LASIK or LASEK according to the patient's choice after each procedure had been thoroughly explained. The patients were followed for 6 months. Best corrected visual acuity (BCVA), uncorrected visual acuity (UCVA), manifest refraction, and wavefront aberrations were measured at baseline and 1, 3, and 6 months after surgery. RESULTS: There were no significant differences in postoperative BCVA, UCVA, and manifest refraction between groups. The mean root-mean-square wavefront error of HOAs for a scotopic pupil in the wavefront-guided LASIK group was significantly smaller than that in the wavefront-guided LASEK group at 1 month. Analyzing individual Zernike coefficients, the spherical aberration and second coma were significantly smaller in the wavefront-guided LASIK group than in the wavefront-guided LASEK group at 1 month. This difference in HOAs between groups disappeared at 3 and 6 months. CONCLUSIONS: The HOAs in the scotopic condition were not different between the wavefront-guided LASIK and LASEK groups beginning 3 months after surgery. However, the HOAs in the LASIK and LASEK groups had a different time course, especially in the case of spherical aberration. This finding suggests that postoperative changes in aberration contribute to the final outcome of wavefront-guided ablation.

Cornea↗

PubMed2006

Mitomycin C inhibits recurrent Avellino dystrophy after phototherapeutic keratectomy.

PURPOSE: To report 4 patients with Avellino corneal dystrophy (ACD) who were treated with 0.02% mitomycin C (MMC) during phototherapeutic keratectomy (PTK). METHODS: ACD was confirmed by polymorphism of the exon region in the BIGH3 gene using polymerase chain reaction followed by DNA sequencing analysis. Three patients with recurrent ACD and 1 patient with primary ACD underwent PTK. Intraoperative 0.02% MMC was applied topically with a soaked microsponge. RESULTS: There was no recurrence of ACD in the heterozygotes, but there were recurrences with best-corrected visual acuity of 20/30 in the 2 homozygotes. CONCLUSION: Intraoperative use of topical 0.02% MMC in conjunction with PTK may prevent or delay the recurrence of ACD for at least for 1 year.

Adult↗

PubMed2006

Comparison of corneal thickness after the instillation of topical anesthetics: proparacaine versus oxybuprocaine.

PURPOSE: To compare changes in human corneal thickness after the instillation of proparacaine with those after oxybuprocaine instillation with time over a period of 10 minutes. METHODS: Eighteen healthy young participants were recruited. Proparacaine was used in the right eye and oxybuprocaine in the left. Right and left baseline corneal thicknesses were measured every 30 seconds for 10 minutes using a noncontact specular microscope by 1 observer. Baseline corneal thickness was defined as the average of all values taken over 10 minutes. Changes in corneal thickness were measured every 20 seconds for 10 minutes after the administration of 1 drop of 0.5% proparacaine onto the right cornea and 1 drop of 0.4% oxybuprocaine onto the left cornea. RESULTS: Mean baseline right cornea thickness was 531 +/- 45 microm, and that of the left cornea was 531 +/- 42 microm. The corneal thickness after proparacaine increased by 8.6 microm ( approximately 4.5-12.6 microm, 95% CI) and then returned to baseline within 80 seconds. Corneal thickness after applying oxybuprocaine increased by 7.7 microm (3.6-11.2 microm, 95% CI) and then returned to baseline within 80 seconds. There was a second transient increase about 5 minutes later after proparacaine instillation but no additional transient increase after oxybuprocaine instillation. CONCLUSION: Oxybuprocaine is similar to proparacaine in terms of the severity of its effect on corneal thickness. Corneal thickness instability may occur for 5 minutes after proparacaine administration. Changes in corneal thickness after topical anesthetic instillation should be considered when performing measurements for refractive surgery or central corneal thickness in glaucoma patients.

Adult↗

PubMed2006

Avellino corneal dystrophy exacerbated after LASIK: scanning electron microscopic findings.

PURPOSE: To evaluate the ultrastructure of the cornea of Avellino corneal dystrophy (ACD) exacerbated by LASIK. METHODS: Three ACD patients with exacerbation of granular corneal deposits after LASIK underwent surgical removal of the corneal flap. The corneal flap was processed for scanning electron microscopy (SEM). RESULTS: SEM of all patients showed abnormal granular clusters in the fibrils of the corneal flap. CONCLUSION: Laser in situ keratomileusis induces corneal collagen abnormalities and adhesions of granular material in ACD patients.

Adult↗

PubMed2006

Exacerbation of Avellino corneal dystrophy after LASIK in North America.

PURPOSE: To report the first case of Avellino corneal dystrophy exacerbation after LASIK in a white or North American patient. METHODS: Case report and literature review. RESULTS: A 25-year-old white female developed progressive corneal opacities after LASIK. Preoperative examination had revealed only subtle white corneal opacities in each eye. The patient's mother had similar corneal opacities. DNA analysis of the patient revealed a heterozygous mutation at the R124H location in the BIGH3 gene. CONCLUSIONS: LASIK can exacerbate Avellino corneal dystrophy and should be avoided in patients with this condition. A careful history and genetic analysis can identify affected patients and those at risk.

Adult↗

PubMed2006

Preserved peripheral corneal clarity after surgical trauma in patients with Avellino corneal dystrophy.

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Adult↗

PubMed2006

Effects of corneal neovascularization on the manifestations of Avellino corneal dystrophy (granular corneal dystrophy type II).

PURPOSE: To evaluate the corneal deposits of Avellino corneal dystrophy (ACD) in patients with corneal neovascularization from pterygium or phthisis bulbi as a way of understanding the pathogenesis of ACD. METHODS: Five patients with ACD with pterygium, 10 patients with ACD (age >50 years) without pterygium, 1 patient with ACD with phthisis bulbi with corneal neovascularization, and 1 patient with ACD with phthisis bulbi without corneal neovascularization were examined. The corneal deposits of all patients were assessed by slit-lamp examination and reviewed with biomicroscopic photographs. The distance between the limbus and the nearest corneal opacities was measured. RESULTS: In eyes with vascularized nasal pterygia, there was a granule-free zone adjacent to the advancing edge of the pterygium so that the distance between the nasal limbus and the most nasally located granule exceeds that of the distance between the limbus and the closest granule elsewhere on the cornea. In patients with ACD with phthisis bulbi, no granular deposits were observed in the cornea with neovascularization, but there were deposits in the cornea without neovascularization. CONCLUSION: Corneal neovascularization prevents the deposition of corneal opacities in patients with ACD.

Adult↗

PubMed2006

Mycobacterium abscessus keratitis after LASIK with IntraLase femtosecond laser.

A healthy 38-year-old woman developed 2 white spots in her left eye 2 weeks after bilateral laser in situ keratomileusis (LASIK) using the IntraLase femtosecond laser. Initial treatment included levofloxacin 0.5% but was unsuccessful. The surgeon irrigated the interface and repositioned the flap due to a worsened lesion. She was referred to us after the keratitis had not improved. The flap was lifted for collection of the specimen and irrigation of the interface. The keratitis was treated with intensive topical clarithromycin 1%, amikacin 1.25% and oral clarithromycin, which improved her clinical condition. She developed a toxic reaction to amikacin 1.25%, which was replaced by moxifloxacin 0.5%. Mycobacterium abscessus was identified. The keratitis resolved over 2 months. Five months after treatment, the patient had a visual acuity of 20/20 with correction. Nontuberculous mycobacteria should be considered as an etiologic agent, even in cases of infectious keratitis after LASIK using the femtosecond laser.

Adult↗

PubMed2006

Induced expression of insulin-like growth factor-1 by amniotic membrane-conditioned medium in cultured human corneal epithelial cells.

PURPOSE: To determine the effect of amniotic membrane-conditioned medium (AMCM), via insulin-like growth factor (IGF)-1 induction, on human corneal epithelial cell (HCEC) proliferation. METHODS: HCECs were cultured from corneal limbal tissue with supplemented hormonal epithelial medium (SHEM). After administration of AMCM, cell proliferation was evaluated with an MTT assay and DNA synthesis with methyl-[(3)H]-thymidine incorporation assay. RT-PCR and Western immunoblot analyses were performed, to determine potential inducible factors that may be associated with AMCM-induced cell proliferation. Neutralizing anti-IGF-1 antibody and small interfering (si)RNA were also used to clarify the role of IGF-1 in AMCM-induced HCEC proliferation. RESULTS: HCEC proliferation increased after AMCM treatment. Of the cytokines known to be associated with HCEC proliferation, only IGF-1 expression was upregulated in response to AMCM in a dose- and time-dependent manner. The IGF-1 induction effect was found on both AMCM from live AM and from cryopreserved AM. HCEC proliferation was also increased by addition of exogenous IGF-1. AMCM-induced HCEC proliferation was inhibited in the presence of neutralizing anti-IGF-1 antibody and IGF-1 siRNA. Finally, Akt phosphorylation was increased in HCECs after AMCM treatment and was inhibited by IGF-1 siRNA. CONCLUSIONS: IGF-1 is induced by AMCM during HCEC proliferation, and this induction may play an important role in the amniotic membrane during HCEC proliferation and migration in several intractable corneal epithelial defects.

Amnion↗

PubMed2006

Insulin-like growth factor-1 induces migration and expression of laminin-5 in cultured human corneal epithelial cells.

PURPOSE: The effects of insulin-like growth factor (IGF)-1 on laminin (Ln)-5 and the associated integrins during in vitro HCEC migration were examined. Also investigated were the effects of IGF-1 on the migration of human corneal epithelial cells (HCECs). METHODS: HCEC migration was examined by wound-healing and chemoattraction assays. For migration inhibition assays, HCECs were pretreated with inhibitors of the IGF-1 receptor (alphaIR3), the PI3-K/AKT pathway (LY294002), and the MEK-ERK pathway (PD98059). The expression levels of Ln-5 and fibronectin (Fn) were determined by Western blot analysis, and the expression levels of the beta1 and alpha3 integrins were determined by confocal microscopy and Western blot analysis. The migration inhibition with anti-integrin alpha3 and beta1 antibodies was also determined. RESULTS: HCEC migration was significantly increased in the presence of IGF-1 and Ln-5. IGF-1 enhanced the production of Ln-5 in both a dose- and time-dependent manner, and this upregulation was blocked by pretreatment with alphaIR3 or LY294002. IGF-1 treatment upregulated expression of beta1 integrin, but not alpha3 integrin. The HCEC migration facilitated by IGF-1 was inhibited with the anti-integrin antibody for beta1. However, there was no cross-talk between Ln-5 and integrin beta1 production. CONCLUSIONS: The results reveal that IGF-1 induces HCEC migration through the independent production of Ln-5 and beta1 integrin, which are directed at least in part by activation of the PI3-K/AKT pathway, but are not affected by the MEK-ERK pathway.

Blotting, Western↗

PubMed2006

Measurement of contrast sensitivity and glare under mesopic and photopic conditions following wavefront-guided and conventional LASIK surgery.

PURPOSE: To compare contrast and glare vision in a prospective study of eyes treated using conventional and wavefront-guided LASIK surgery. The reproducibility of a glaremeter device used to quantitatively measure glare and halo was also determined. METHODS: Ninety-two eyes of 46 patients underwent conventional LASIK surgery and 104 eyes of 52 patients underwent wavefront-guided LASIK surgery. Visual acuity, glare disability measured using a glaremeter, and contrast sensitivity assessed using a Pelli-Robson chart were measured monthly for 6 months postoperatively. Glaremeter testing was performed under both mesopic (5.4 +/- 0.4 cd/m2) and photopic (78.3 +/- 4.4 cd/m2) conditions. To evaluate the reproducibility of the glaremeter, 36 eyes of 18 nonoperated myopic patients were tested. RESULTS: The coefficient of variation and the reliability coefficient for the glare test were 13.6% and 95.2%, respectively. The glaremeter showed that glare disability under mesopic conditions differed between conventional and wavefront-guided LASIK eyes over 6-month follow-up (907.5 +/- 491.5 vs 986.1 +/- 448.0 pixels preoperatively and 1717.1 +/- 521.2 vs 1407.8 +/- 411.3 pixels at 6 months, P<.0001). At 6 months, contrast sensitivity log values were 1.62 +/- 0.31 and 1.78 +/- 0.34 for conventional and wavefront-guided LASIK eyes, respectively (P=.010). The visual complaint score was lower in the wavefront-guided LASIK group (P=.0116). CONCLUSIONS: Compared to conventional ablation, wavefront-guided ablation provided superior outcomes in terms of postoperative glare under mesopic conditions, subjective complaints, and contrast sensitivity. In addition, it appears the glaremeter can be used for clinical quantitative evaluation of glare and halo.

Adult↗

PubMed2006

Use of peripheral chatter lines for free-flap alignment during LASIK.

PURPOSE: To report a case in which an improperly rotated free flap was successfully repositioned using peripheral chatter lines as a reference. METHODS: A 30-year-old woman with irregular astigmatism as the result of an improperly rotated free flap during LASIK underwent repositioning of the corneal flap correspondingly along the chatter lines. RESULTS: Best spectacle-corrected visual acuity improved from 20/100 to 20/20 following the procedure. Corneal topography showed improvement in the astigmatism and the Placido disk pattern. CONCLUSIONS: When marks on a free flap are obscured during LASIK, periodic chatter lines can be used for realignment if no other landmarks are available.

Adult↗

PubMed2005

Topical 0.1% prednisolone lowers nerve growth factor expression in keratoconjunctivitis sicca patients.

PURPOSE: To compare nerve growth factor (NGF) levels in tears and on the ocular surfaces of normal control and non-Sjögren's type keratoconjunctivitis sicca subjects, and to investigate the effect of 0.1% prednisolone eyedrops on NGF levels in keratoconjunctivitis sicca patients. DESIGN: Prospective, double-masked, randomized, comparative clinical trial. PARTICIPANTS: Forty-one keratoconjunctivitis sicca patients and 23 age- and gender-matched healthy subjects. METHODS: Baseline tear NGF levels were measured in keratoconjunctivitis sicca patients and healthy control subjects using enzyme-linked immunosorbent assays. Keratoconjunctivitis sicca patients received 0.1% prednisolone drops in one eye and 0.1% hyaluronic acid drops in the other, 3 times a day for 28 days. Also, impression cytology (IC) and immunostaining for NGF on conjunctival epithelium were performed on both groups. MAIN OUTCOME MEASURES: Tear NGF/total tear protein (TP) concentration ratio, IC and NGF immunocytologic staining, subjective symptom scale, tear breakup time, and Schirmer values. RESULTS: Keratoconjunctivitis sicca patients were found to have baseline tear NGF concentrations higher than those of age- and gender-matched healthy control subjects (65.9+/-14.5 vs. 122.1+/-45.3 pg/mug, P<0.0001). In keratoconjunctivitis sicca patients, prednisolone treatment for 28 days resulted in a decrease in tear NGF levels, symptom scores, and IC scores, whereas hyaluronic acid treatment had no such effect (68.2+/-25.0 pg/mug vs. 108.0+/-43.4 pg/mug, P<0.0001 for tear NGF/TP ratio; 2.16+/-1.01 vs. 3.39+/-1.50, P = 0.0014 for symptom scale; 1.05+/-0.67 vs. 1.61+/-0.86, P = 0.0317 for IC). Measurements taken at both 14 and 28 days indicated that neither prednisolone nor hyaluronic acid treatment affected breakup time or Schirmer values. CONCLUSION: Keratoconjunctivitis sicca patients showed elevated levels of tear NGF, which were decreased by treatment with 0.1% prednisolone. These data suggest that ocular surface NGF may play an important role in ocular surface inflammation processes associated with dry eyes.

Administration, Topical↗

PubMed2005

Expression of tumor necrosis factor alpha and matrix metalloproteinase-9 in surgically induced necrotizing scleritis.

BACKGROUND: Surgically induced necrotizing scleritis is primarily managed with immunosuppressive regimens. Such treatments can alter inflammatory cytokines and products such as tumor necrosis factor-alpha (TNF-alpha) and matrix metalloproteinase-9 (MMP-9), which are an important proinflammatory cytokine and a tissue-degrading protease involved in necrosis of some ocular tissues. OBJECT: To evaluate TNF-alpha and MMP-9 in the tear or sclera of surgically induced necrotizing scleritis. METHODS: After tear collection from healthy and diseased eyes of 2 patients, immunoblot analysis using monoclonal antibody specific for human TNF-alpha and MMP-9 was performed. In another patient, scleral tissues were obtained during scleral allograft surgery, and the same immunoblot analysis was done. RESULTS: The level of TNF-alpha and MMP-9 was increased in tear fluid from patients compared to that of control volunteers and returned to the control level after treatment. The diseased sclera showed an increased expression of MMP-9 compared to that of the normal donor sclera. CONCLUSIONS: TNF-alpha and MMP-9 may suggest disease activity of surgically induced necrotizing scleritis and can be altered by proper immunosuppressive treatment.

Aged↗