PubMed Health⌕ Search

Biomedical subjects

Elmer Y Tu

Publications and source records attributed to Elmer Y Tu.

5 recordsLinked to original sources
PubMed2006

Epidemiological characteristics of a Chicago-area Acanthamoeba keratitis outbreak.

PURPOSE: To characterize Acanthamoeba keratitis (AK) cases and analyze the geographical distribution within the Chicago-Gary-Kenosha metropolitan area, Chicago, Illinois, USA. DESIGN: Retrospective, population-based cohort study. METHODS: All AK cases diagnosed at the University of Illinois at Chicago Cornea Service from June 1, 2003, to November 30, 2005, were included in analysis. Patients with keratitis were defined as cases through confocal microscopy, histology, and/or positive cultures. Exploratory analyses were performed to evaluate whether AK cases were unequally distributed geographically. County population data were extracted from US Census 2000 data, and rates were age-standardized to Cook County. Poisson regression analysis was used to estimate the age-standardized rate ratio (RR) between AK cases and county of residence. Current cases (June 1, 2003 to November 30, 2005) were compared with historical cases (June 1, 2000 to November 30, 2002) to determine if the current rate of AK diagnosis differed from historical rates. RESULTS: Forty AK cases were diagnosed between June 1, 2003 and November 30, 2005. The average (+/-SD) age of patients with AK was 28.0 +/- 15.0 years (range, 13 to 70 years), 52.5% were men, and 95.0% wore contact lenses. Estimated RR measures demonstrated increased rates for all counties relative to Cook, and were significant for both DuPage County (RR 3.59; 95% confidence interval [95% CI] 1.44, 8.39) and Will County (RR 3.66; 95% CI 1.18 to 9.56). Current AK diagnosis rates were significantly higher than historical rates (RR 6.67; 95% CI 3.05 to 17.52). CONCLUSIONS: AK cases are increasing in frequency. The increased rates are unevenly distributed in the study area. Further research is warranted to better understand the increase and unusual geographical distribution.

Acanthamoeba Keratitis↗
PubMed2006

The effect of temperature on the antimicrobial activity of Optisol-GS.

PURPOSE: To determine the survival of different bacteria inoculated in Optisol-GS at refrigerated storage temperature (6 degrees C) and after subsequent warming to room temperature (19-22 degrees C). METHODS: Staphylococcus aureus, Enterococcus faecium, Streptococcus pneumoniae, and Pseudomonas aeruginosa were chosen from stock clinical isolates for inclusion in the study. The first group consisted of 12 Optisol-GS vials. The second group consisted of 12 Optisol-GS vials containing corneas inappropriate for transplantation according to the Eye Bank Association of America (EBAA) protocols. Each group was inoculated with 3 concentrations of approximately 10, 10, and 10 colony-forming units (CFU)/mL of each bacterial species and then refrigerated per EBAA protocol. After 48 hours of refrigeration, all vials were placed at room temperature (RT) and counts were performed at 48, 50 (2 hour RT), 54 (6 hour RT), 60 (12 hour RT), 72 (24 hour RT), and 96 (48 hour RT) hours. At 96 hours, the corneal tissue from 10 and 10 inocula were cultured. All samples underwent serial dilution, spiral plating on blood agar plates, and incubation at 35 degrees C. Viable colony counts were determined at 24 hours. RESULTS: Except for the 10 CFU/mL inocula of P. aeruginosa, all isolates were viable after 48 hours of refrigeration. Rapid bactericidal activity was observed against P. aeruginosa after 2 hours at RT, with complete sterilization by 6 hours. The rate and extent of killing against S. aureus were influenced by the initial inoculum. Bactericidal activity was achieved after 2 hours at RT with 10 CFU/mL of S. aureus versus 24 hours with the 10 inoculum. Of note, bactericidal activity was not observed against S. pneumoniae and E. faecium following 24 hours of storage at RT. The presence of corneal tissue did not affect viable counts, with counts from corneal tissue cultures reflecting the counts seen from Optisol-GS after 48 hours at RT. CONCLUSIONS: The antimicrobial activity of Optisol-GS was reduced at refrigerated temperature and enhanced at RT. Bactericidal activity was not observed against E. faecium at either refrigerated temperature or RT.

Anti-Bacterial Agents↗
PubMed2006

Gemella haemolysans infectious crystalline keratopathy.

PURPOSE: To report a case of infectious crystalline keratopathy caused by Gemella haemolysans. METHODS: Observational case report. A 65-year-old woman underwent penetrating keratoplasty for contact lens-related Acanthamoeba keratitis and developed a nonhealing epithelial defect. Despite continued prophylaxis with topical gatifloxacin, small superficial stromal opacities were noted and cultured 6 months after penetrating keratoplasty. The opacities coalesced into a fine, crystalline keratopathy in the superficial stroma with persistent overlying epithelial defect. RESULTS: Culture results from corneal scraping showed more than 100 colonies of G. haemolysans. Topical vancomycin was instituted, with complete resolution of the crystalline keratopathy and epithelial defect over the next 2 months. CONCLUSIONS: G. haemolysans can be a causative organism of infectious crystalline keratopathy. This infection can arise in a postkeratoplasty patient despite prophylaxis with a fourth-generation fluoroquinolone.

Administration, Topical↗
PubMed2005

Contact lens overrefraction variability in corneal power estimation after refractive surgery.

PURPOSE: To evaluate the accuracy and precision of the contact lens overrefraction (CLO) method in determining corneal refractive power in post-refractive-surgery eyes. SETTING: Refractive Surgery Service and Contact Lens Service, University of Illinois, Chicago, Illinois, USA. METHODS: Fourteen eyes of 7 subjects who had a single myopic laser in situ keratomileusis procedure within 12 months with refractive stability were included in this prospective case series. The CLO method was compared with the historical method of predicting the corneal power using 4 different lens fitting strategies and 3 refractive pupil scan sizes (3 mm, 5 mm, and total pupil). Rigid lenses included 3 9.0 mm overall diameter lenses fit flat, steep, and an average of the 2, and a 15.0 mm diameter lens steep fit. Cycloplegic CLO was performed using the autorefractor function of the Nidek OPD-Scan ARK-10000. Results with each strategy were compared with the corneal power estimated with the historical method. The bias (mean of the difference), 95% limits of agreement, and difference versus mean plots for each strategy are presented. RESULTS: In each subject, the CLO-estimated corneal power varied based on lens fit. On average, the bias between CLO and historical methods ranged from -0.38 to +2.42 diopters (D) and was significantly different from 0 in all but 3 strategies. Substantial variability in precision existed between fitting strategies, with the range of the 95% limits of agreement approximating 0.50 D in 2 strategies and 2.59 D in the worst-case scenario. The least precise fitting strategy was use of flat-fitting 9.0 mm diameter lenses. CONCLUSIONS: The accuracy and precision of the CLO method of estimating corneal power in post-refractive-surgery eyes was highly variable on the basis of how rigid lense were fit. One of the most commonly used fitting strategies in clinical practice--flat-fitting a 9.0 diameter lens-resulted in the poorest accuracy and precision. Results also suggest use of large-diameter lenses may improve outcomes.

Adult↗