Browsing by Author "Chen, Dawei"

Now showing 1 - 2 of 2
  • Thumbnail Image
    The Role of CD44 in Concanavalin A-Induced Hepatitis
    Chen, Dawei (Virginia Tech, 1999-02-18)
    Administration of Concanavalin-A (Con A) induces severe injury to the hepatocytes in mice and is considered to be a model for human hepatitis. In the current study, we investigated the role of CD44 in Con A induced hepatitis. Although immune cells have been identified as the causative agent of Con A-induced hepatitis, the exact mechanism of pathogenesis remains unclear. When Con A was injected into CD44 wild type (WT) mice, it induced hepatitis as evident from increased plasma aspartate aminotransferase (AST) levels accompanied by active infiltration of mononuclear cells in the liver and significant induction of apoptosis. Interestingly, Con A injected C57BL/6 CD44-knockout (KO) mice exhibited increased hepatitis with higher levels of apoptosis in the liver and increased plasma AST levels when compared to the CD44 WT mice. Also, transfer of T cells from Con A injected CD44-KO mice into CD44 WT mice induced higher levels of hepatitis when compared to transfer of similar cells from CD44 WT mice into CD44 WT mice. The increased hepatitis seen in CD44-KO mice was partially due to increased production of cytokines such as TNF-a, IL-2 and IFN-g, but not Fas or FasL. Also, it was not caused by altered presence of T cell subsets. The increased susceptibility of CD44 KO mice to hepatitis correlated with increased resistance of T cells from CD44 KO mice to undergo apoptosis when compared to the CD44 WT mice. Together, these data demonstrate that activated T cells use CD44 to undergo apoptosis, and dysregulation in this pathway could lead to increased pathogenesis in a number of diseases, including hepatitis.
  • Thumbnail Image
    Studying the Functional Genomics of Stress Responses in Loblolly Pine With the Expresso Microarray Experiment Management System
    Heath, Lenwood S.; Ramakrishnan, Naren; Sederoff, Ronald R.; Whetten, Ross W.; Chevone, Boris I.; Struble, Craig A.; Jouenne, Vincent Y.; Chen, Dawei; van Zyl, Leonel; Grene, Ruth (Hindawi, 2002-01-01)
    Conception, design, and implementation of cDNA microarray experiments present avariety of bioinformatics challenges for biologists and computational scientists. The multiplestages of data acquisition and analysis have motivated the design of Expresso, asystem for microarray experiment management. Salient aspects of Expresso includesupport for clone replication and randomized placement; automatic gridding, extraction ofexpression data from each spot, and quality monitoring; flexible methods of combiningdata from individual spots into information about clones and functional categories; and theuse of inductive logic programming for higher-level data analysis and mining. Thedevelopment of Expresso is occurring in parallel with several generations of microarrayexperiments aimed at elucidating genomic responses to drought stress in loblolly pineseedlings. The current experimental design incorporates 384 pine cDNAs replicated andrandomly placed in two specific microarray layouts. We describe the design of Expresso aswell as results of analysis with Expresso that suggest the importance of molecularchaperones and membrane transport proteins in mechanisms conferring successfuladaptation to long-term drought stress.