2006 merck/merial - School of Veterinary Medicine - Louisiana State ...

Plasma concentrations of potassium penicillin G obtained in swine after administration via drinking waterBryan Kerling*, Mike Apley, Marlin HooglandKansas State University College of Veterinary MedicineIt is a typical practice in the swine industry, to administer potassium penicillin G through the water to nursery pigs totreat and/or prevent infections caused by Streptococcus suis. The doses routinely used in the field raise questions as towhether adequate amounts of penicillin G are absorbed by the pigs. We will administer a dose through a proportioner into thewater supply to the pigs beginning on day 0 of the study. The dose will remain constant throughout the 3 day length of thestudy. Blood will be drawn from 40 randomly selected pigs on four occasions on day 3 of the study. Plasma levels ofpenicillin will be determined using HPLC. This information will then be compared to MICs of common pathogensencountered by nursery pigs, including streptococcus suis, in order to evaluate current doses and determine if changes need tobe made to the current dosing regimens.Evaluation of Bone Response on Porous Surfaces Using A Canine Total Hip ModelOlivia Kilian 1 *, Elizabeth Pluhar, D.V.M, Ph.D. 1 , Renwen Zhang, M.D., Ph.D. 2 , Nena Dimaano 2College of Veterinary Medicine, 1352 Boyd Ave C352, University of Minnesota, Saint Paul, MN, 55108 1Stryker Orthopaedics, 325 Corporate Drive, Mahwah, NJ 07430 2Although the overall success with uncemented hip implants is established, bone ingrowth into the porous surfacethat provides implant stability has been less than expected. New types of porous coatings are continually being developed totry to improve fixation of uncemented acetabular cups. The goal of this study is to evaluate bony response and ingrowth offour different porous surface coatings on acetabular cups; Praxis, a novel coating, with and without hydroxyapatite coatingversus cobalt-chromium beads and a modified titanium, both control surfaces. To test the hypothesis that different porouscoatings will result in variable volume fractions of bony ingrowth, randomly staged bilateral total hip replacements (THR)will be performed on 24 normal, healthy canines. The contralateral surgery will be performed 10 weeks after the initial THRsurgery, yielding 6 samples of each treatment at 6 and 16 weeks. Radiographic signs of implant loosening will be checked at16 weeks and compared to immediate postoperative films. After sacrifice at 16 weeks, the acetabula will be sectioned andqualitative and quantitative analyses measuring volume of bone ingrowth, apposition and depth penetration; tissue response;and signs of inflammation will be performed to compare differences among the types of porous coatings. This study mayprove that a new porous coating has better bone ingrowth that gives greater implant stability and decreased bone resorptionthat causes implant loosening compared to currently available implants.Assessing the effects of Cued Fear Conditioning and the role of the Amygdala in REM Sleep Patterns ofMale S-D RatsD. Knight, V. Madan, G. Mann, F. Brennan, R. Ross, A. MorrisonUniversity of Pennsylvania, Department of Animal Biology, School of Veterinary MedicineUniversity of Pennsylvania, Department of Psychiatry, School of MedicineMedical Research Service, Philadelphia VA Medical CenterStressful events and emotional states, controlled by the amygdala, affect the quality of sleep. In rats, fearconditioning- where a tone or conditioned stimulus (CS) is paired to a shock or unconditioned stimulus (US) - can be used todemonstrate the effect stressors have on sleep. In response to fear-conditioning, rats show changes in the quality of REMsleep, which are modulated by the Lateral Amygdala (LA). In fact, both lesions to the LA and the nonspecific neuronalinhibitor lidocaine prevent changes in REM normally seen in fear-conditioned rats. However, non-specific antagonism of theregion has few clinical applications. Work in vitro has demonstrated that serotonin (5-HT) placed in the LA inhibits GABAneurons thought to mediate the linkage of the US, a foot shock, with the CS, a tone, in intact animals. If GABA neurons areindeed responsible for this linkage, and if 5-HT inhibits GABA neurons in vivo, then 5-HT injections in the LA shouldinhibit changes in REM. To test this hypothesis, we are implanting 12 male Sprague Dawley rats with EEG and EMGelectrodes as well as bilateral cannulae in the LA. After a period of adaptation and a baseline sleep and behavior recording,experimental rats are given injections of 1.5 mM 5-HT and fear-conditioned. Control rats are given injections of artificialCSF prior to training. The training paradigm consists of five 800Hz, 90 dB, 5 second tones paired to 1 second 1.0 mAshocks. Sleep recordings are taken at 24 hours and 2 weeks post training after a presentation of 5 tones without shocks. Thebehavior of the animals is video recorded for offline scoring of freezing and ultrasonic vocalization. Sleep recordings arethen scored in 10s intervals. The results of the study should determine whether 5-HT can be used to block the effects of fearconditioningon sleep, an important step in developing possible treatments for posttraumatic stress disorder, which is aninterest of the laboratory.83