Sun Xg

The antibacterial efficacy of an aceraceous plant [Shantung maple (Acer truncatum Bunge)] may be related to inhibition of bacterial β-oxoacyl-acyl carrier protein reductase (FabG)

Polyphenols, including flavonoids, are the major components of the extracts from aceraceous plants. They possess remarkable antibacterial and antitumour activity. Our study focused on whether the inhibition of the bacterial type II fatty acid synthesis system is the mechanism for the antibacterial effect of the related plant polyphenols. Extracts obtained from the fallen leaves of the Shantung maple (Acer truncatum Bunge) using different solvents, and the related pure compound PGG (1,2,3,4,6‐penta‐O ‐galloyl‐β‐d‐glucose), potently inhibited the FabG (β‐oxoacyl‐ACP reductase) steps in the fatty‐acid‐elongation cycle with the IC50 values between 0.9 and 7.2 μg/ml. An ethyl acetate extract appeared to inhibit FabG reductase in a mixed manner with NADPH, as did PGG with NADPH, demonstrating that they interfered with the binding of the cofactor to the enzyme. Gram‐positive and Gram‐negative bacteria and some fungi were used to evaluate the antibacterial abilities of different extract samples. The experiments showed that a higher polyphenol content of the extracts led to a more potent inhibitory capacity against FabG, thus enhancing the antibacterial efficacy.

Pharmacokinetics of terbinafine in the rabbit ocular tissues after topical administration.

Objective: To determine the distribution of terbinafine in the cornea and aqueous humor after topical administration. Methods: A corn oil ointment of terbinafine 0.2% (resolved in sterile corn oil) was applied to the conjunctival sac of albino rabbits twice (with a 5-min interval). The concentration of terbinafine was determined with high-performance liquid chromatography (HPLC) 5, 15, 30, 60, 120 and 240 min after administration of terbinafine. Results: After topical administration, the concentration of terbinafine increased gradually, reached a peak (1.39 µg/ml at 30 min in the cornea and 82.9 ng/ml at 30 min in aqueous humor, respectively) and then decreased. The concentration was 0.18 µg/g at 240 min in the cornea, but terbinafine could not be tested at 120 min in aqueous humor. Conclusions: Topical ophthalmic terbinafine 0.2% could penetrate into the cornea and aqueous humor at concentrations adequate for inhibition of fungus.

A new in vivo confocal microscopy prognostic factor in Acanthamoeba keratitis.

PURPOSE To identify prognostic factors associated with poor outcomes in Acanthamoeba keratitis (AK). METHODS Patients with AK treated at the Beijing Tongren Hospital between January 2008 and January 2012 were included. All patients had corneal scrapings and/or cultures positive for Acanthamoeba and visible cysts on in vivo confocal microscopy (IVCM) examination. Therapeutic penetrating keratoplasty was performed in patients who experienced disease progression or lack of improvement on topical therapy. Patient demographics, clinical characteristics, previous treatment, and IVCM characteristics of the cysts were evaluated. Patients defined as poor outcomes were those requiring therapeutic penetrating keratoplasty. Logistic regression was used to estimate the odd-ratio identifying prognostic factors associated with a poor outcome. RESULTS Twenty-nine eyes of 29 patients were diagnosed as having AK over the study period. IVCM showed clusters and/or chains of Acanthamoeba cysts in 9 patients. Fifteen patients underwent therapeutic penetrating keratoplasty. A late-disease stage on presentation, a deep location of cysts, and clusters or chains of cysts observed with IVCM were significantly associated with a worse outcome. On multivariate analysis, only clusters or chains of cysts observed with IVCM were independently associated with a poor prognosis. CONCLUSION The presence of clusters or chains of Acanthamoeba cysts could be a new IVCM criterion allowing the identification of AK patients requiring therapeutic penetrating keratoplasty.