Browsing by Author "Brown, Jennifer A."
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- Elution of Antibiotics from a Novel Cross-linked Dextran Gel: In vivo QuantificationHart, Samantha Kym (Virginia Tech, 2009-06-08)Amikacin-, vancomycin- or amikacin/clindamycin-impregnated gel was placed subcutaneously on either side of horses' necks a total of 6 times each. Interstitial fluid was collected at 0, 4, 8, 12 and 24 hours, and days 2 through 10, via capillary ultrafiltration probes placed within the incision (0cm) and 1.5cm laterally. Plasma or serum was collected at days 0, 1 and 7. Biopsy samples were obtained at the completion of the study. A histomorphologic score was assigned to each sample, and the differences in mean scores between treatment (gel) and control incisions were assessed using Wilcoxon signed rank test. Amikacin and vancomycin samples were analyzed via fluorescence polarization immunoassay; clindamycin samples were analyzed via high performance liquid chromatography. Concentrations greater than 2000 times the MIC of vancomycin and clindamycin, greater than 1000 times the MIC of amikacin, and greater than 800 times the MIC of amikacin (amikacin/clindamycin gel) were obtained at 0cm. Mean concentrations remained above MIC for vancomycin and clindamycin for 10 days (0cm) and 8 days (1.5cm); for 9 days (0cm) and 7 days (1.5cm) for amikacin gel; and for 9 days (0cm) and 5 days (1.5cm) for amikacin (amikacin/clindamycin gel). Mean plasma amikacin and vancomycin concentrations were negligible; serum clindamycin concentrations were greater than MIC (0.52µg/ml and 0.63µg/ml) at 24 hours and 7 days respectively. There were no significant differences in histomorphologic scores between treatment and control incisions. Cross-linked dextran gel is a safe, effective alternative for local antibiotic delivery in horses, with substantially high local concentrations and minimal systemic absorption for amikacin- and vancomycin-impregnated gels.
- Equine Emergency Preparedness in VirginiaPorr, C. A. Shea; Brown, Jennifer A. (Virginia Cooperative Extension, 2010)Emergency plans for evacuating horses in the event of natural or man-made disasters.
- Serum concentrations of lidocaine and its metabolites after prolonged infusion in healthy horsesDickey, Emma Jane (Virginia Tech, 2009-06-11)Lidocaine continuous-rate infusions (CRI) are the most commonly used prokinetic in equine practice for the treatment of post-operative ileus and are also increasingly being used in pain management, such as in cases of severe laminitis, and are often used for prolonged durations. To date only limited time/concentration relationships of lidocaine administered as a short term (24hours) CRI to horses are reported. This study examined the time/concentration profile of lidocaine and its active metabolites (GX, MEGX) during a 96 hour lidocaine infusion in eight mature healthy horses. Serum lidocaine concentrations reached steady state by three hours and did not accumulate thereafter. The serum concentration of lidocaine was above the target therapeutic concentration (980ng/ml) only at 6 and 48 hours. The serum lidocaine concentration did not reach the range described as potentially causing toxicity (>1850ng/ml). The MEGX metabolite did not accumulate over time, while the GX metabolite accumulated significantly up to 48 hours and then remained constant. The serum concentrations of lidocaine, MEGX and GX were below the limit of detection within 24 hours of discontinuation of the infusion. None of the horses developed any signs of lidocaine toxicity during the study. It was concluded that the metabolism of lidocaine was not significantly impaired by prolonged infusion, contrasting with studies in dogs and humans. No adverse effects were observed in this study, which with the lack of lidocaine accumulation suggests that prolonged infusions are safe. However the accumulation of GX, a potentially toxic active metabolite, is cause for concern.