In vitro elution of amikacin from four hydrogel preparations: A pilot study.

OBJECTIVE: To determine in vitro elution of amikacin from poloxamer 407 NF, 1% carboxymethylcellulose (CMC), 3% CMC, 5% CMC, and control (sterile water). STUDY DESIGN: Descriptive in vitro. SAMPLE POPULATION: Triplicate samples from each experimental group. METHODS: Amikacin solution was prepared in poloxamer 407 NF, 1% CMC, 3% CMC, 5% CMC, or sterile water. Then, 1 ml of phosphate-buffered saline (PBS) was added to each of three aliquots per base and the samples were incubated at 37°C. PBS was removed and replaced at 1, 4, 8, 12, 24, 48, 72, 96, 120, 144, 168, 192, 216, and 240 hours and amikacin concentration was measured. RESULTS: The highest median concentration of amikacin in the eluent of poloxamer 407 NF, 3% CMC, and 5% CMC was observed at 48 hours: 3300, 3030, and 2190 µg/ml, respectively. The highest median concentration of amikacin in the eluent of 1% CMC and sterile water were observed at 1 hour: 13300 and 15600 µg/ml, respectively. Median eluent concentration of amikacin exceeded 2000 µg/ml (the reported minimum inhibitory concentration [MIC] of certain biofilm-producing methicillin-resistant Staphylococcus pseudintermedius) from 24 to 96 hours for poloxamer 407 NF, 24-72 hours for 3% CMC, 48-72 hours for 5% CMC, 1-4 hours for 1% CMC, and 1-4 hours for sterile water. CONCLUSION: Amikacin elution from tested substances reached or exceeded target MIC during the 240 hours tested. CLINICAL SIGNIFICANCE: Hydrogel-amikacin solutions may be useful topical treatment options for some infected wounds. In vivo safety and efficacy should be evaluated.

Chernobyl-level radiation exposure damages bumblebee reproduction: a laboratory experiment.

The consequences for wildlife of living in radiologically contaminated environments are uncertain. Previous laboratory studies suggest insects are relatively radiation-resistant; however, some field studies from the Chernobyl Exclusion Zone report severe adverse effects at substantially lower radiation dose rates than expected. Here, we present the first laboratory investigation to study how environmentally relevant radiation exposure affects bumblebee life history, assessing the shape of the relationship between radiation exposure and fitness loss. Dose rates comparable to the Chernobyl Exclusion Zone (50-400 µGy h-1) impaired bumblebee reproduction and delayed colony growth but did not affect colony weight or longevity. Our best-fitting model for the effect of radiation dose rate on colony queen production had a strongly nonlinear concave relationship: exposure to only 100 µGy h-1 impaired reproduction by 30-45%, while further dose rate increases caused more modest additional reproductive impairment. Our data indicate that the practice of estimating effects of environmentally relevant low-dose rate exposure by extrapolating from high-dose rates may have considerably underestimated the effects of radiation. If our data can be generalized, they suggest insects suffer significant negative consequences at dose rates previously thought safe; we therefore advocate relevant revisions to the international framework for radiological protection of the environment.

Eradication of common mynas Acridotheres tristis from Denis Island, Seychelles.

BACKGROUND: In Seychelles, the common myna has been shown to have a negative impact on endangered endemic birds on Denis Island, interfering with breeding attempts and attacking adult endemic birds at their nests. This stimulated an attempt to eradicate the island's mynas. RESULTS: The eradication was undertaken in three phases, overall killing 1186 mynas and lasting 5 years. Decoy trapping was the most effective method for catching mynas, but the last birds were shot. Decoy trapping was compromised by catches of non-target species. Data collection from killed birds indicated that trapping did not favour either sex, and that most breeding occurred during the wetter season, November to March. CONCLUSIONS: Eradication of mynas from small tropical islands is feasible. The Denis Island eradication was prolonged by difficulties in management and staffing. Using volunteers, the cost of the eradication was similar to that of eradicating rodents from the island. In future eradication attempts in Seychelles, possible food stress during the drier season (May to September) might facilitate trapping at this time. Habitat management, especially the removal of short mown grass, could enhance eradication progress. Continued monitoring is needed to confirm eradication and detect any immigration, and also to record responses in the endemic birds. © 2016 Society of Chemical Industry.