[The changes of ocular bacterial isolates and in vitro antimicrobial susceptibility in the past six years].

OBJECTIVE: To analyze the changes of ocular bacterial isolates and their susceptibility to ciprofloxacin, ofloxacin, levofloxacin, gatifloxacin and tobramycin in Henan Province in the past six years. METHODS: Retrospective study of ocular bacterial isolates and their in vitro antimicrobial susceptibility test results of Henan Eye Institute in the past six years. RESULTS: A total of 2044 bacterial isolates were classified into 39 kinds in the past six years, which were mainly from the conjunctival sac. Staphylococcus epidermidis was the most common, followed by Pseudomonas aeruginosa, Staphylococcus aureus and Bacillus cereus. All kinds of the ocular bacteria had the highest susceptibility to gatifloxacin (92.3%) among the tested drugs. Rods were more sensitive to quinolone drugs than cocci and gram-positive rods were more sensitive to tobramycin than the other types of germs. The drug's susceptibility of the four kinds of quinolone except ciprofloxacin decreased year by year with a decreasing ladder fashion every two years in the susceptibility change of levofloxacin in the past six years, while the susceptibility of tobramycin increased slowly from 2004 to 2008 and then decreased. Staphylococcus epidermidis susceptibility to every drug had the similar trend with the general changes in the past six years, that is, their susceptibility to ofloxacin decreased significantly since 2008, their susceptibility to gatifloxacin and tobramycin reduced significantly in 2009. Although Pseudomonas aeruginosa susceptibility to all the drugs had no significant change, for all gram-negative rods, their susceptibility to the four kinds of quinolone drugs were higher than their susceptibility to tobramycin while their susceptibility to levofloxacin and gatifloxacin reduced significantly as time passed by, especially from the year 2008 to 2009. CONCLUSIONS: The most common ocular bacterial isolates were Staphylococcus epidermidis, followed by Pseudomonas aeruginosa. Ocular bacterial isolates' susceptibility to gatifloxacin in vitro was significantly higher than to other drugs in every year but decreased significantly in 2009 while their susceptibility to ofloxacin and levofloxacin decreased significantly since 2008. Their susceptibility to tobramycin increased slowly from 2004 to 2008 and then decreased.

[Activity of butenafine against ocular pathogenic filamentous fungi in vitro].

OBJECTIVE: To investigate antifungal activity of butenafine in comparison with that of natamycin, amphotericin B and fluconazole against ocular pathogenic filamentous fungi in vitro. METHODS: It was an experimental study. Susceptibility tests were performed against 260 isolates of ocular pathogenic filamentous fungi by broth dilution antifungal susceptibility test of filamentous fungi approved by the Clinical and Laboratory Standards Institute (CLSI) M38-A document. The isolates included Fusarium spp. (136), Aspergillus spp. (98), Alternaria alternata (9), Curvularia lunata (3), and unusual ocular pathogens (14). Final concentration ranged from 0.008 to 16.000 mg/L for butenafine, from 0.031 to 16.000 mg/L for amphotericin B and natamycin, and from 0.5 to 256.0 mg/L for fluconazole. Following incubation at 35 degrees C for 48 h, minimal inhibitory concentration (MIC) was determined according to the CLSI M38-A document. For amphotericin B and natamycin, the MIC was defined as the lowest drug concentration that prevented any discernible growth. For butenafine and fluconazole, the MIC was defined as the lowest concentration in which an approximately 75% reduction compared to the growth of the control was observed. Candida parapsilosis ATCC22019 was used as quality control strains to validated the results. Mean MIC and MIC range, the MIC at which 50% of the isolates tested were inhibited (MIC(50)) and the MIC at which 90% of the isolates tested were inhibited (MIC(90)), were provided for all the isolates tested by using descriptive statistical analysis with the statistical SPSS package (version 13.0). RESULTS: MIC(90) of butenafine, natamycin, amphotericin B and fluconazole were 4, 8, 2 and 512 mg/L for Fusarium spp., respectively; 0.063, 32.000, 2.000 and 256.000 mg/L for Aspergillus spp., respectively; 0.5, 8.0, 2.0 and 128.0 mg/L for Alternaria alternate, respectively; 0.125, 2.000, 0.500 and 4.000 mg/L for Curvularia lunata, respectively; and 1, 4, 1 and 256 mg/L for unusual ocular pathogens, respectively. CONCLUSIONS: Butenafine exhibits potent antifungal activity against a wide variety of ocular pathogenic fungi, especially for Aspergillus spp., Alternaria alternata, Curvularia lunata, and some unusual ocular pathogens and may have a role in future studies of antifungal eye drops and treating fungal keratitis.

[Comparison of the activities of silver nitrate with those of three antifungal agents against ocular pathogenic fungi in vitro].

OBJECTIVE: To investigate antifungal activity of silver nitrate compared with fluconazole, ketoconazole and amphotericin B against ocular pathogenic fungi in vitro. METHODS: It was an experimental study. Susceptibility tests were performed against 260 isolates (15 genera and 29 species) of ocular pathogenic fungi by broth dilution antifungal susceptibility testing of filamentous fungi (M38-A) approved by National Committee for Clinical Laboratory Standards (NCCLS). Final concentrations ranged from 0.031 to 16.000 mg/L for silver nitrate, ketoconazole and amphotericin B, from 0.5 - 256.0 mg/L for fluconazole. Minimum inhibitory concentration (MIC) was defined as the lowest drug concentration that showed absence of growth or complete growth inhibition (100%). The end points were determined as 100% growth inhibition for silver nitrate and amphotericin B, and > or = 75% growth inhibition for ketoconazole and fluconazole. RESULTS: The MICs at which 90% of isolates were inhibited (MIC(90)) of silver nitrate, ketoconazole, amphotericin B and fluconazole were 2.000, 512.000, 32.000 and 2.000 mg/L for Fusarium species, respectively; 1.000, 256.000, 2.000 and 2.000 mg/L for Aspergillus species, respectively; 2.000, 128.000, 4.000 and 2.000 mg/L for Alternaria alternate, respectively; 2.000, 4.000, 0.125 and 0.500 mg/L for Curvularia lunata, respectively; and 1.000, 256.000, 1.000 and 1.000 mg/L for unusual ocular pathogens, respectively. Silver nitrate was highly active against Aspergillus species (92.9% susceptible at a MIC of < or = 1.0 mg/L) and Fusarium species (96.3% susceptible at a MIC of < or = 2.0 mg/L). 95.6% of Fusarium species and 90.8% of Aspergillus species exhibited resistance to fluconazole, 44.1% of Fusarium species and 42.9% of Aspergillus species exhibited resistance to amphotericin B, 66.2% of Fusarium species exhibited resistance to ketoconazole. The activity of silver nitrate against the fluconazole-resistant, ketoconazole-resistant and amphotericin B-resistant strains was high. CONCLUSION: Silver nitrate has promising activity against a wide variety of ocular pathogenic fungi in vitro, and may have a role in future studies of antifungal eye drops and treating fungal keratitis.

Decision-making and prepotent response inhibition functions in excessive internet users.

INTRODUCTION: Excessive Internet use (EIU), also described as Internet addiction or pathological Internet use, has already become a serious social problem around the world. Some researchers consider EIU as a kind of behavioral addiction. However, there are few experimental studies on the cognitive functions of excessive Internet users (EIUers) and limited data are available to compare EIU with other addictive behaviors, such as drug abuse and pathological gambling. METHODS: In the present study, we examined EIUers' functions of decision-making and prepotent response inhibition. Two groups of participants, EIUers and controls, were compared on these two functions by using a Gambling Task and a Go/no-go Task, respectively. RESULTS: Compared with controls, EIUers selected significantly less net decks in the Gambling Task (P=.007). Furthermore, the EIUers made progress in selecting strategy, but more slowly than did the control group (EIUers, chunk 3 > chunk 1, P<.001; controls, chunk 2 > chunk 1, P<.001). Interestingly, EIUers' accuracy during the no-go condition was significantly higher than that of controls (P=.018). CONCLUSION: These results showed some similarities and dissimilarities between EIU and other addictive behaviors such as drug abuse and pathological gambling. The findings from the Gambling Task indicated that EIUers have deficits in decision-making function, which are characterized by a strategy learning lag rather than an inability to learn from task contingencies. EIUers' better performance in the Go/no-go Task suggested some dissociation between mechanisms of decision-making and those of prepotent response inhibition. However, EIUers could hardly suppress their excessive online behaviors in real life. Their ability of inhibition still needs to be further studied with more specific assessments.

[Emphasizing the research for ocular drug delivery system].

Choosing appropriate drug delivery system can apparently improve drug efficacy, prolong action time and decrease adverse reaction. In recent years, with the progress of macromolecule chemistry, the research of ocular drug delivery system has been developed rapidly. The present article reviews the progress of ocular drug delivery system and its development in our country. This article also discusses how to exploit the macromolecule polymer material with independence intellectual property rights, and how to promote the studies of intraocular pharmacokinetics and ocular toxicology about new ocular drug delivery system.

[The effect of propyl gallate on the activity of various antifungal drugs against filamentous fungi in vitro].

OBJECTIVE: The influence of an antioxidant, propyl gallate (PG), on the activity of amphotericin B (AMB), terbinafine (TBF), butenafine (BTF) and ketoconazole (KCZ) against ocular pathogenic filamentous fungi in vitro was investigated to determine whether PG could increase the antifungal activity. METHODS: Susceptibility tests were performed against 6 isolates of ocular pathogenic filamentous fungi (Fusarium solanae, Fusarium moniliforme, Fusarium poae, Fusarium oxysporum, Aspergillus fumigatus and Aspergillus flavus) and 2 quality control strains (Candida krusei ATCC 6258 and Cadida parapsilosis ATCC 22019) by the NCCLS M38-P broth microdilution method (MIC). PG was added to the incubation media at a final concentration of 400 microg/ml. Antifungal agents were serially two-fold diluted and final dilutions were made in 1640 and PG-1640 culture media to a concentration ranging from 0.0313 to 16 microg/ml for AMB, TBF, BTF and KCZ. One hundred microl of the corresponding diluted inoculum suspension was added to each well of the microdilution tray. The MIC end-point of AMB was determined as 100% growth reduction and the MIC end-point of TBF, BTF, KCZ and PG was determined as 75% growth reduction as compared with the turbidity produced by the control well. RESULTS: At a concentration of 400 microg/ml, PG did not show any antifungal activity under these experimental conditions. The combination of PG (400 microg/ml) with amphotericin B revealed a remarkably increased activity against all of the isolates of ocular pathogenic filamentous fungi and quality control strains. In the combination of PG with terbinafine, a remarkably increased activity was observed against Fusarium solanae, Fusarium poae, Fusarium oxysporum, Aspergillus fumigatu and Aspergillus flavus. The combination of PG with butenafine had remarkably synergistic effect against Fusarium solanae, but did not synergistic or even showed antagonistic effect for other isolates. The combination of PG with ketaconazole was synergistic against Fusarium solanae, but was antagonistic against all other isolates. CONCLUSIONS: Combination of PG and amphotericin has remarkably synergistic effect against all tested ocular pathogenic filamentous fungi isolates. Combination of PG and terbinafine has remarkably synergistic effect against some isolates. The PG-amphotericin combination and the PG-terbinafine combination may have a role in future studies of antifungal eye drops.

[The concentrations of fluoroquinolones in prevention of Staphylococcus epidermidis from mutant in ocular surface].

OBJECTIVE: To examine the mutant prevention concentration (MPC) of the four fluoroquinolones to Staphylococcus epidermidis from ocular in vitro, and to compare the MPCs to the minimal inhibitory concentrations (MICs). METHODS: The MICs of the ciprofloxacin, ofloxacin, levofloxacin and gatifloxacin were determined by the standard twofold agar dilution methods of the National Committee for Clinical Laboratory Standards (NCCLS). The single colony of Staphylococcus epidermidis on the blood agar plate was inoculated into Muller Hinton broth. The turbidity of the actively growing broth culture was adjusted to 1 x 10(8) cfu/ml and then the broth was diluted 1:10 and 1 microl of the diluted broth was inoculated on the Muller Hinton agar surface for each drug in different concentrations. The final inoculum was approximately 10(4) cfu. The MPCs were measured by mix-bacterial methods. The concentrations of the drugs used in MPC's determination were determined according to the drug's MIC(50) to the bacteria. 1 ml of drug's broth and 19 ml suspension of the bacteria and Muller Hinton agar were added into one plate with the final 10(10) cfu of inoculum. RESULTS: The lowest MIC(90) was gatifloxacin at 0.25 mg/L, the medium MIC(90) is levofloxacin at 0.50 mg/L, the highest MIC(90) at 1.00 mg/L was detected in ciprofloxacin and ofloxacin. The MPC(50) and MPC(90) for gatifloxacin were 1.00 mg/L and 2.00 mg/L respectively, which were the lowest concentration among the four drugs tested. The same parameter of the MPC(50) (2.00 mg/L) and MPC(90) (4.00 mg/L) was obtained in levofloxacin and ciprofloxacin, the MPC(50) for ofloxacin was as high as levofloxacin and ciprofloxacin at 2.00 mg/L but its MPC(90) was 8.00 mg/L. CONCLUSIONS: The new fluoroquinolones shows high effect on anti-bacterial Staphylococcus epidermidis. Gatifloxacin and levofloxacin may play a role in prevention Staphylococcus epidermidis from mutation.

[Ocular pharmacokinetics of 0.5% pilocarpine with sodium hyaluronate in rabbits].

OBJECTIVE: To compare the pharmacokinetics of 0.5% pilocarpine containing sodium hyaluronate with 1% generic pilocarpine solution. METHODS: One hundred albino rabbits were divided into 20 groups, each consisting of 5 animals. Ten groups received 0.5% pilocarpine containing sodium hyaluronate and 10 groups received 1% generic pilocarpine solution as control. The aqueous humor was withdrawn at 5, 10, 20, 30, 40, 60, 90, 120, 150, and 180 min after instillation. The drug was extracted from aqueous humor with dichloromethane and was detected by reversed phase high performance liquid chromatography (HPLC). RESULTS: The average recovery rate of pilocarpine from aqueous humor was 98.2%. The minimum detectable concentration was 0.025 micro g/ml. The peak concentration and half-life of pilocarpine in aqueous humor were 4.46 micro g/ml at 10 min and 31.83 min, respectively, in the experimental group. Whereas, the peak concentration and half-life of pilocarpine in aqueous humor were 2.25 micro g/ml at 20 min and 22.98 min, respectively, in the control group. The peak concentration of pilocarpine in aqueous humor in the experimental group was 1.98 (P < 0.05) times higher than the control group. The area under curve of the drug concentration-time (AUC(0 - 180)) in the experimental group was 1.75 times higher than the control group. CONCLUSION: Pilocarpine (0.5%) containing sodium hyaluronate significantly increased the peak concentration of pilocarpine, shortened the time of reaching peak concentration and prolonged the half-life in aqueous humor. These results indicate that 0.5% pilocarpine with sodium hyaluronate significantly increases ocular bioavailability of pilocarpine.