Jonghoon Shin

The Effect of Corneal Biomechanical Properties on Rebound Tonometer in Patients With Normal-Tension Glaucoma

PURPOSE To evaluate the effects of corneal biomechanical properties on intraocular pressure (IOP) measured with the ICare, and to compare IOP readings obtained with ICare, Ocular Response Analyzer (ORA), and Goldmann applanation tonometry (GAT) in normal-tension glaucoma (NTG) and normal subjects. DESIGN Prospective, cross-sectional, comparative study. METHODS IOP was measured with ICare, ORA, and GAT. All subjects had corneal hysteresis (CH) and corneal resistance factor (CRF), which were measured with ORA; and central corneal thickness (CCT), axial length, spherical equivalent, and keratometry. RESULTS This study enrolled 97 eyes of 97 NTG patients and 89 eyes of 89 normal subjects. CCT, CH, and CRF in NTG patients were significantly lower than those in normal subjects (P = .033, P = .006, and P = .003). The difference in IOP between techniques was highly significant in NTG patients (P < .001), while there was no significant difference in IOP values between techniques in normal controls (P = .931). ICare readings were significantly lower than corneal-compensated IOP in NTG patients (P = .014). CH and CRF were significantly associated with IOP measurements with ICare in NTG and normal subjects (P < .001). The greater difference between IOPcc and ICare in NTG patients was significantly influenced by the lower CH (P < .001). CONCLUSIONS Since ICare is a convenient way to measure IOP, ICare is a reasonable option as an alternative tonometer in NTG patients. However, the clinician must consider that the corneal biomechanical characteristics in NTG can cause ICare to underestimate IOP.

The multi-faceted potential of plant-derived metabolites as antimicrobial agents against multidrug-resistant pathogens

Multidrug-resistant (MDR) pathogens are currently causing serious problems globally in the medical setting. Improper and extensive usage of antibiotics results in a selective pressure supporting the rise of antibiotic-resistant microbes. Many key cellular bacterial components, including enzymes and small noncoding RNAs (sRNAs), and their involvement in MDR have been well studied, but exploiting such components in eradicating these pathogens requires further study. Delineation of many mechanisms that underpin the known MDR pathways necessitates urgent development of new specific strategies to control the rise of MDR pathogens. Botanical derivatives are comparatively safer than currently used antibiotics and exert multiple therapeutic benefits associated with their high efficacy. Numerous plant-derived compounds display synergistic activity with antibiotics against many MDR pathogens. Such plant derivatives include alkaloids, flavonoids, terpenoids, and tannins. A synthetic biological approach, e.g., metabolic engineering of secondary metabolites, can be utilized to exploit the natural metabolic pathways against MDR microbes. In this review, we focused on the major threats of antibiotic resistance, and the utilization of plant-derived compounds as alternative therapeutic agents to limit the rise of MDR pathogens.

Relationship between corneal biomechanical properties and structural biomarkers in patients with normal-tension glaucoma: a retrospective study

BackgroundWe evaluated the relationships between corneal biomechanical properties and structural parameters in patients with newly diagnosed, untreated normal-tension glaucoma (NTG).MethodsAll subjects were evaluated using an Ocular Response Analyzer (ORA) measuring corneal hysteresis (CH) and the corneal resistance factor (CRF). Central corneal thickness (CCT), Goldmann applanation tonometric (GAT) data, axial length, and the spherical equivalent (SE), were also measured. Confocal scanning laser ophthalmoscopy was performed with the aid of a Heidelberg retina tomograph (HRT III). We sought correlations between HRT parameters and different variables including CCT, CH, and the CRF. Multiple linear regression analysis was performed to identify significant associations between corneal biomechanical properties and optic nerve head parameters.ResultsWe enrolled 95 eyes of 95 NTG patients and 93 eyes of 93 normal subjects. CH and the CRF were significantly lower in more advanced glaucomatous eyes (P = 0.001, P = 0.008, respectively). The rim area, rim volume, linear cup-to-disc ratio (LCDR), and mean retinal nerve fiber layer (RNFL) thickness were significantly worse in more advanced glaucomatous eyes (P < 0.001, P < 0.001, P < 0.001, and P = 0.001). CH was directly associated with rim area, rim volume, and mean RNFL thickness (P = 0.012, P = 0.028, and P = 0.043) and inversely associated with LCDR (P = 0.015), after adjusting for age, axial length, CCT, disc area, GAT data, and SE. However, in normal subjects, there were no significant associations between corneal biomechanical properties and HRT parameters.ConclusionsA lower CH is significantly associated with a smaller rim area and volume, a thinner RNFL, and a larger LCDR, independent of disc size, corneal thickness, intraocular pressure, and age.

Intracranial fibromuscular dysplasia presenting as various ocular manifestations

Fibromuscular dysplasia (FMD) is a nonatherosclerotic, noninflammatory vascular disease that mainly affects renal, extracranial carotid, and vertebral arteries. Intracranial FMD is uncommon unlike extracranial or renal FMD, and the primary manifestation of intracranial FMD is intracranial aneurysm. We report an unusual case of intracranial FMD showing various ocular manifestations, including central retinal artery occlusion, transient monocular blindness, and oculomotor nerve palsy without renal involvement.

Goniosynechialysis for secondary angle closure glaucoma in a pseudophakic patient after vitrectomy and silicone oil injection.

Department of Ophthalmology, Pusan National University School of Medicine, Busan 602-739, Korea Medical Research Institute, Pusan National University Hospital, Busan 602-739, Korea 3Department of Ophthalmology, Pusan National University Yangsan Hospital, Yangsan, Gyeongsangnam-do 626-770, Korea Correspondence to: Ji-Woong Lee. Department of Ophthalmology, Pusan National University School of Medicine, 1-10, Ami-Dong, Seo-Ku Busan 602-739, Korea. glaucoma@pnu.ac.kr Received: 2013-08-09 Accepted: 2014-02-12

Role of acid responsive genes in the susceptibility of Escherichia coli to ciclopirox

Antibiotic resistance poses a huge threat to the effective treatment of bacterial infections. To circumvent the limitations in developing new antibiotics, researchers are attempting to repurpose pre-developed drugs that are known to be safe. Ciclopirox, an off-patent antifungal agent, inhibits the growth of Gram-negative bacteria, and genes involved in galactose metabolism and lipopolysaccharide (LPS) biosynthesis are plausible antibacterial targets for ciclopirox, since their expression levels partially increase susceptibility at restrictive concentrations. In the present study, to identify new target genes involved in the susceptibility of Escherichia coli to ciclopirox, genome-wide mRNA profiling was performed following ciclopirox addition at sublethal concentrations, and glutamate-dependent acid resistance (GDAR) genes were differentially regulated. Additional susceptibility testing, growth analyses and viability assays of GDAR regulatory genes revealed that down-regulation of evgS or hns strongly enhanced susceptibility to ciclopirox. Further microscopy and phenotypic analyses revealed that down-regulation of these genes increased cell size and decreased motility. Our findings could help to maximise the efficacy of ciclopirox against hard-to-treat Gram-negative pathogens.

Mobile lens-induced angle closure glaucoma and rubeosis iridis in Sturge Weber syndrome.

Yangsan Hospital, Yangsan 50612, Korea 2Department of Ophthalmology, Pusan National University Hospital, Busan 49241, Korea 3Research Institute for Convergence of Biomedical Science and Technology, Yangsan Pusan National University Hospital, Yangsan 50612, Korea 4Medical Institute, School of Medicine, Pusan National University, Busan 46241, Korea Correspondence to: Ik Soo Byon. Department of Ophthalmology, Pusan National University Yangsan Hospital, Yangsan 50612, Korea. isbyon@naver.com Received: 2014-05-12 Accepted: 2014-11-03