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

+/- 2.96 g) (P= 0.12, U=11.0). These data suggest that the contamination differentially affects the growth of P. maniculatus.Field necropsies allowed acquisition of liver, kidney and testes for histopathology and collection of RNA in these tissues.We hypothesized that exposed mice exposed would be more prone to abnormal pathology in the liver, kidney and testes.Samples will be analyzed with light microscopy to assess abnormal pathology. To assess the effects of heavy metal toxicityat a genetic level, we are using Affymetrix microarrays to measure changes in RNA expression in the liver, kidney and testes.We will use changes in RNA expression of specific genes to see how the contamination is influencing the health of theanimals. This project will help determine if habitat in the Cherokee County Superfund Site has been sufficiently restored forhealthy wildlife communities.Searching ion receptor and neurotransmitter genes for linkage to canine idiopathic epilepsyLena DeTar*, Jim Mickelson, Kari Eckenstedt, Katie MinorUniversity of Minnesota School of Veterinary MedicineUsing polymorphic microsatellite repeats within or very close to canine genes for Potassium channels, acetylcholinereceptors and GABA receptors, this ongoing project attempts to correlate incidence of tandem repeat alleles to knownincidence of inherited epilepsy in four canine breeds (Vizsla, Greater Swiss Mountain Dog, English Springer Spaniel,Beagle). Alleles are identified using a Beckman CEQ genetic analysis machine. Specific genes were chosen by theirimplication or involvement in human idiopathic epilepsy, and for one breed (Vizsla), pedigree analysis figures into statisticalcalculations. Of those tested so far, no one gene’s allele distribution has been positively correlated with the frequency ofepilepsy in any canine breed.Development of a murine in vitro model for assessing characteristics of enterocytes and intestinalmacrophages during development of spontaneous and bacteria-induced colitisBrittney Fierro*, Helle Bielefeldt-Ohmann.Department of Microbiology, Immunology and Pathology, College of Veterinary Medicine and BiomedicalSciences, Colorado State University.Both pathogenic and nonpathogenic enteric bacteria interact with enteric immune cells in the large intestine. Thisinteraction can initiate the inflammatory process and lead to colitis, e.g. IBD. Enterocytes are known to modulate thisprocess. These complex interactions are not fully understood and are difficult to study in vivo. Thus, an in vitro modelwould be useful to identify and characterize the events involved. A better understanding of the pathogenesis of colitis shouldprove useful in targeting treatment and/or prevention modalities. Both normal and mdr1a -/- mice are used. Mdr1a -/- miceare deficient in a multi-drug-resistant transporter; this deficiency allows bacterial toxins and antigens to pass the epithelialbarrier, causing spontaneous colitis. To model induced and spontaneous colitis in vitro, a model simulating the in vivosystem is constructed. Full-thickness samples from the large intestine are first removed for histopathology. Enterocytes andmacrophages are then harvested from the large intestine. Enterocytes are plated onto matrigel-coated transwells.Macrophages are separated from contaminating cells via Percoll gradient centrifugation, then co-cultured with enterocytes.Bacteria are added either to the apical (enterocyte) chamber or to the basolateral (macrophage) chamber. To assess thecharacteristics of both enterocytes and intestinal macrophages, several methods are used. RNA from both enterocytes andmacrophages is harvested at varying time points. The RNA will then be used for microarrays to determine cytokine mRNAexpression. Additionally, macrophages are spotted onto slides and phenotypically characterized. Expression of macrophagesurface markers will be assessed by immunohistochemistry and/or flow cytometry. All results are pending. In futureexperiments, lymphocytes will also be harvested, co-cultured, and assessed for cytokine mRNA expression.A comparison between MDV production in feather pulp versus feather follicle epithelium (FFE)James B. Finlay 1 , John R. Dunn 2 , Richard L. Witter 2 and Robert F. Silva 2Michigan State University College of Veterinary Medicine 1USDA ARS Avian Disease and Oncology Laboratory, 3606 E. Mt. Hope Road, East Lansing, MI 2Marek's disease is a lymphoproliferative disease in chickens caused by the alphaherpesvirus Marek's disease virus(MDV). After a cytolytic phase in lymphoid tissue (i.e. thymus, spleen and bursa) the virus travels to the feather follicleepithelium (FFE). The FFE is the only known location that sheds cell-free MDV. One method of measuring viral load in abird is to quantify viral DNA in feather tips. The current study was designed to determine whether quantification of viralDNA in feather tips is an accurate reflection of the quantity of shed virus. A total of 57 birds (6 days old) were infected withserotype 1 MDV of varying pathotype and shedding potential, specifically JM/102W, rMd5, 648A p.8 and 648A p.50. Theywere divided into 4 isolators with multiple birds and 12 isolators with single birds. Feather samples were collected at 3 timepoints (14, 21 and 28 days). Dust was also collected and analyzed for MDV as the true measure of viral shedding.Comparisons of MDV load as reflected in the e FFE tips and in the pulp within the feather shaft to that determinedfrom the dust samples will allow us to verify or negate the validity of each as a measure of viral shedding. Currently, DNA97