Medicine and Health Sciences Commons^™

Rac-1 And Iqgap Are Potential Regulators Of E-Cadherin-Catenin Interactions During Murine Preimplantation Development., David R Natale, Andrew J Watson

Obstetrics & Gynaecology Publications

Adherens junction formation is fundamental for compaction and trophectoderm differentiation during mammalian preimplantation development. We recently isolated an IQGAP-2 cDNA from a differential display-polymerase chain reaction screen of bovine preimplantation developmental stages. IQGAP-1 and -2 proteins mediate E-cadherin-based cell-to-cell adhesion through interactions with beta-catenin and the Rho GTPases, rac1 and cdc42. Our study demonstrates IQGAP-1,-2, rac-1 and cdc42 mRNAs are present throughout murine preimplantation development. IQGAP-1 and rac-1 protein distribution changes from predominantly plasma membrane associated to predominantly cytoplasmic as the embryo progresses through cleavage divisions and compaction to the blastocyst stage.

The Gamma-Subunit Of The Na-K-Atpase As A Potential Regulator Of Apical And Basolateral Na+-Pump Isozymes During Development Of Bovine Pre-Attachment Embryos., L C Barcroft, S E Gill, A J Watson

Obstetrics & Gynaecology Publications

Expression and activity of the Na-K-ATPase within the basolateral membrane domains of the trophectoderm epithelium provide the driving force for accumulation of Na(+) and Cl(-) across the nascent epithelium, mediating fluid movement into the forming blastocoel. Within the trophectoderm of the bovine blastocyst, multiple isozymes of the Na-K-ATPase are expressed. Immunolocalization has demonstrated that the alpha1-isozyme localizes within the basolateral membrane, whereas the alpha 3-isozyme localizes to the apical cell margins. Gene-specific RT-PCR and wholemount indirect immunofluorescence confocal laser scanning microscopy were used to examine expression of the Na-K-ATPase gamma-subunit (a regulatory subunit of the Na-K-ATPase) throughout development of bovine …

Optimisation Of Bile Production During Normothermic Preservation Of Porcine Livers., Charles J. Imber, Shawn D. St Peter, Inigo Lopez De Cenarruzabeitia, Hugh Lemonde, Mike Rees, Andrew Butler, Peter T. Clayton, Peter J. Friend

Manuscripts, Articles, Book Chapters and Other Papers

Machine perfusion of livers may provide a mechanism for extended preservation of marginal donor organs before transplantation, as well as a method for viability assessment. It has proved possible in a series of experimental porcine liver perfusions to maintain liver viability for up to 72 h. However, a reduction in bile production with associated histological evidence of cholestasis was seen after 10 h of perfusion, damaging the biliary canaliculi during the preservation period and leaving these organs in an unacceptable condition for transplantation. It was proposed that reduction in bile production was the result of a relentless depletion of available …

Identification Of The Vibrio Cholerae Enterobactin Receptors Vcta And Irga: Irga Is Not Required For Virulence, Alexandra R. Mey, Elizabeth E. Wyckoff, Amanda G. Oglesby, Eva Rab, Ronald K. Taylor, Shelley M. Payne

Dartmouth Scholarship

The gram-negative enteric pathogen Vibrio cholerae requires iron for growth. V. cholerae has multiple iron acquisition systems, including utilization of heme and hemoglobin, synthesis and transport of the catechol siderophore vibriobactin, and transport of several siderophores that it does not itself make. One siderophore that V. cholerae transports, but does not make, is enterobactin. Enterobactin transport requires TonB and is independent of the vibriobactin receptor ViuA. In this study, two candidate enterobactin receptor genes, irgA (VC0475) and vctA (VCA0232), were identified by analysis of the V. cholerae genomic sequence. A single mutation in either of these genes did not significantly …

Treatment With Soluble Interleukin-15ralpha Exacerbates Intracellular Parasitic Infection By Blocking The Development Of Memory Cd8+ T Cell Response, Imtiaz A. Khan, Magali Moretto, Xiao-Qing Wei, Martha Williams, Joseph D. Schwartzman, F Y. Liew

Dartmouth Scholarship

Interferon (IFN)-γ–producing CD8⁺ T cells are important for the successful resolution of the obligate intracellular parasite Toxoplasma gondii by preventing the reactivation or controlling a repeat infection. Previous reports from our laboratory have shown that exogenous interleukin (IL)-15 treatment augments the CD8⁺ T cell response against the parasite. However, the role of endogenous IL-15 in the proliferation of activated/memory CD8⁺ T cells during toxoplasma or any other infection is unknown. In this study, we treated T. gondii immune mice with soluble IL-15 receptor α (sIL-15Rα) to block the host endogenous IL-15. The treatment markedly reduced the ability …

Hepatic Steatosis And Its Relationship To Transplantation., Charles J. Imber, Shawn D. St Peter, Ashok Handa, Peter J. Friend

Manuscripts, Articles, Book Chapters and Other Papers

Fatty infiltration of the liver is common in the brain-dead donor population and has a strong correlation with primary nonfunction after cold preservation, a condition that is catastrophic to liver transplant recipients. This literature review examines factors associated with the development, diagnosis, quantification, and clinical management of this difficult condition.

Extended Preservation Of Non-Heart-Beating Donor Livers With Normothermic Machine Perfusion., Shawn D. St Peter, C J. Imber, I Lopez, D Hughes, P J. Friend

Manuscripts, Articles, Book Chapters and Other Papers

BACKGROUND: Non-heart-beating donor (NHBD) livers represent an important organ pool, but are seldom utilized clinically and require rapid retrieval and implantation. Experimental work with oxygenated perfusion during preservation has shown promising results by recovering function in these livers. This study compared sanguinous perfusion with cold storage for extended preservation of the NHBD liver in a porcine model.

METHODS: Porcine livers were subjected to 60 min of in vivo total warm ischaemia before flushing, after which they were preserved by one of two methods: group 1 (n = 4), University of Wisconsin (UW) solution by standard cold storage for 24 h; …

Cd8+-T-Cell Immunity Against Toxoplasma Gondii Can Be Induced But Not Maintained In Mice Lacking Conventional Cd4+ T Cells, Lori Casciotti, Kenneth H. Ely, Martha E. Williams, Imtiaz A. Khan

Dartmouth Scholarship

T-cell immunity is critical for survival of hosts infected with Toxoplasma gondii. Among the cells in the T-cell population, CD8⁺ T cells are considered the major effector cells against this parasite. It is believed that CD4⁺ T cells may be crucial for induction of the CD8⁺-T-cell response against T. gondii. In the present study, CD4^−/− mice were used to evaluate the role of conventional CD4⁺ T cells in the immune response against T. gondii infection. CD4^−/− mice infected with T. gondii exhibited lower gamma interferon (IFN-γ) messages in the majority of their …

Differential Synthesis Of Beta-Tubulin Isotypes In Gerbil Nasal Epithelia, Karen Woo, Heather Jensen Smith, Richard F. Ludueña, Richard Hallworth

Journal Articles: Eppley Institute

Compartmentalization of beta-tubulin isotypes within cells according to function was examined in gerbil olfactory and respiratory epithelia by using specific antibodies to four beta-tubulin isotypes (beta(I), beta(II), beta(III), and beta(IV)). Isotype synthesis was cell-type-specific, but the localization of the isotypes was not compartmentalized. All four isotypes were found in the cilia, dendrites, somata, and axons of olfactory neurons. Only two isotypes (beta(I) and beta(IV)) were present in the cilia of nasal respiratory epithelial cells. The beta(IV) isotype, thought to be an essential component of cilia, was present in olfactory neurons and respiratory epithelial cells, which are ciliated, but was not …

Beta-Galactosidase As A Marker Of Ischemic Injury And A Mechanism For Viability Assessment In Porcine Liver Transplantation., Shawn D. St Peter, Charles J. Imber, Inigo Lopez De Cenarruzabeitia, James Mcguire, Tim James, Richard Taylor, Peter J. Friend

Manuscripts, Articles, Book Chapters and Other Papers

Glycohydrolases are a group of enzymes contained predominantly within lysosomes, which are released during Kupffer cell activation or death. One of these, beta-galactosidase, has been proposed as a marker of ischemia-reperfusion injury in the liver because Kupffer cell activation represents a primary event in the injurious reperfusion cascade. In this study, we compared B-galactosidase with more traditional indicators of liver injury and function in a porcine model of liver preservation. Porcine livers were allocated into two groups: group C (n = 5), preserved in University of Wisconsin solution by standard cold storage for 24 hours, and group W (n = …