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Biomedical subjects

N Yokoi

Publications and source records attributed to N Yokoi.

81 records · Page 5Linked to original sources

Acute conjunctivitis associated with biofilm formation on a punctal plug.

BACKGROUND: Punctal plugs are used for the treatment of tear-deficient type dry eye. We recently examined a case of acute conjunctivitis associated with bacterial biofilm formation on a punctal plug. CASE: A 63-year-old woman diagnosed as having tear-deficient type dry eye came to our hospital with a complaint of soreness in her right eye. Punctal plugs had been inserted into this eye 5 1/2 months previously. On the day of her visit, she presented with acute conjunctivitis. OBSERVATIONS: In biomicroscopical examination, the top of the punctal plug was seen to be covered with a whitish soft material. Microbiological analysis performed on a part of this material was positive for Staphylococcus haemolyticus and Candida tropicalis. Scanning electron microscopy of the removed punctal plug revealed widespread bacterial colonization embedded within an extensive extracellular matrix. Treatment consisted of the replacement of the plug, and administration of a combination of antibacterial eyedrops and preservative-free artificial solution. As a result, the acute conjunctivitis cleared up within 1 month. CONCLUSIONS: This case suggests that a punctal plug poses a potential risk of causing the formation of bacterial biofilm. In such a case, replacement of the plug and/or removal of the accumulated materials should be considered.

Acute Disease↗

Sialic acid in normal human tear fluid.

PURPOSE: We measured the concentration of sialic acid, the terminal component of mucin, in normal diluted human tears. METHODS: Twenty-microliter tear samples were collected from 31 healthy volunteers (average age = 50.7 years) using micropipette after 50 microL instillation of saline. We investigated the correlation of concentration between glycoprotein and sialic acid and the difference between the right and the left eyes, as well as the reproducibility of the sampling procedure. RESULTS: There was significant correlation of the concentration between glycoprotein and sialic acid (right eye: r = 0.952, P <.0001; left eye: r = 0.976, P <.001). There was no significant difference in concentration between the right and the left eyes. Also, the reproducibility was considered acceptable in three measurements of sialic acid using the present procedure. The sialic acid concentration in normal diluted tears was 37.1 microg/mL on average. CONCLUSION: Our data indicates that sialic acid concentration is an indicator for the concentration of glycoprotein and that this method of measurement is applicable to the analysis of mucin-deficient disorders.

Chromatography, High Pressure Liquid↗

Effect of beta-blocker eyedrops on corneal epithelial barrier function.

To investigate the long-term effect of a topically applied beta-blocker on human corneal epithelium, the corneal epithelial barrier function and the superficial cell area of the corneal epithelium were evaluated. Seventeen normal healthy volunteers (without medication), 7 cataract patients (treated with pyrenoxine eyedrops) and 7 glaucoma or ocular hypertension patients (treated with 0.5% timolol maleate) were assigned to this study. The eyedrops had been used on a daily basis for at least 3 months. In the evaluation of corneal epithelial barrier function, fluorescein uptake was measured using a slitlamp fluorophotometer after application of 3 microl of 0.5% fluorescein for 10 min. In the evaluation of the superficial cell area, the central corneal epithelium was measured by tandem scanning confocal microscopy (TSCM). The healthy control and timolol groups were compared. Corneal fluorescein uptake in the healthy control, pyrenoxine and timolol groups was 20.3 +/- 3.2, 21.5 +/- 4.0 and 76.2 +/- 30.0 ng/ml (mean +/- standard error), respectively. There was a significantly higher fluorescein uptake in the timolol group compared to the pyrenoxine group (p = 0.0088) and the healthy control group (p = 0.0055). TSCM showed no significant difference in the superficial cell areas of the corneal epithelium between the healthy control and timolol groups. beta-Blocker eyedrops decreased the corneal epithelial barrier function. Their application was not accompanied by any biomicroscopic change in the superficial cell area.

Adrenergic beta-Antagonists↗