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  • 1
    Online Resource
    Online Resource
    La Vergne :New Central Book Agency,
    Keywords: Transition metal complexes-Spectra. ; Electronic books.
    Description / Table of Contents: The purpose of this book is to familiarize students with the concepts, methods and applications of Crystal Field Theory as well as Ligand Field Theory to a point where the literature on the subject can be followed without much difficulty. Large number of tables and diagrams and figures enhance the value of the highly readable text. Suitable advanced reading is suggested in the bibliography at the end of each chapter. Problems of varying degree of difficulty are included after certain chapters to provide practice in the methods of CFT and LFT.
    Type of Medium: Online Resource
    Pages: 1 online resource (515 pages)
    Edition: 1st ed.
    ISBN: 9781642873191
    DDC: 543.5
    Language: English
    Note: Cover -- Contents -- Preface -- CHAPTER 1 Electron Energy Levels for Transition Metal Ions -- CHAPTER 2 Crystal Field Splitting Diagrams and Electron Energy Levels for Transition Metal Complexes -- CHAPTER 3 Term Diagrams -- CHAPTER 4 Some Theoretical Aspects of Electronic Spectra -- CHAPTER 5 Selection Rules, Vibronic Coupling, Dichroism, Band Intensities and Bandwidths -- CHAPTER 6 Charge Transfer Spectra -- CHAPTER 7 Electronic Spectra of dn Ions -- APPENDICES -- List of Tables -- Index of Absorption Spectra -- General Subject Index.
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  • 2
    Publication Date: 2012-11-20
    Description: Hepatitis C virus (HCV)-mediated liver disease progression may reflect distinct molecular mechanisms for increased hepatocyte growth and hepatic stellate cell activation. In this study, we have observed that primary human hepatocytes, when infected in vitro with cell culture-grown HCV genotype 1a or 2a, display viral RNA and protein expression. Infected hepatocytes displayed a fibroblast-like shape and an extended life span. To understand the changes at the molecular level, we examined epithelial-mesenchymal transition (EMT) markers. Increased mRNA and protein expression levels of vimentin, snail, slug, and twist and a loss of the epithelial cell marker E-cadherin were observed. Snail and twist, when examined separately, were upregulated in chronically HCV-infected liver biopsy specimens, indicating an onset of an active EMT state in the infected liver. An increased expression level of fibroblast-specific protein 1 (FSP-1) in the infected hepatocytes was also evident, indicating a type 2 EMT state. Infected hepatocytes had significantly increased levels of phosphorylated β-catenin (Ser 552 ) as an EMT mediator, which translocated into the nucleus and activated Akt. The phosphorylation level of β-catenin at Thr 41 /Ser 45 moieties was specifically higher in control than in HCV-infected hepatocytes, implicating an inactivation of β-catenin. Together, these results suggested that primary human hepatocytes infected with cell culture-grown HCV display EMT via the activation of the Akt/β-catenin signaling pathway. This observation may have implications for liver disease progression and therapeutic intervention strategies using inhibitory molecules.
    Print ISSN: 0022-538X
    Electronic ISSN: 1098-5514
    Topics: Medicine
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  • 3
    Publication Date: 2015-10-23
    Description: We have previously reported that hepatitis C virus (HCV) infection of primary human hepatocytes (PHH) induces the epithelial mesenchymal transition (EMT) state and extends hepatocyte life span (S. K. Bose, K. Meyer, A. M. Di Bisceglie, R. B. Ray, and R. Ray, J Virol 86:13621–13628, 2012, http://dx.doi.org/10.1128/JVI.02016-12 ). These hepatocytes displayed sphere formation on ultralow binding plates and survived for more than 12 weeks. The sphere-forming hepatocytes expressed a number of cancer stem-like cell (CSC) markers, including high levels of the stem cell factor receptor c-Kit. The c-Kit receptor is regarded as one of the CSC markers in hepatocellular carcinoma (HCC). Analysis of c-Kit mRNA displayed a significant increase in the liver biopsy specimens of chronically HCV-infected patients. We also found c-Kit is highly expressed in transformed human hepatocytes (THH) infected in vitro with cell culture-grown HCV genotype 2a. Further studies suggested that HCV core protein significantly upregulates c-Kit expression at the transcriptional level. HCV infection of THH led to a significant increase in the number of spheres displayed on ultralow binding plates and in enhanced EMT and CSC markers and tumor growth in immunodeficient mice. The use of imatinib or dasatinib as a c-Kit inhibitor reduced the level of sphere-forming cells in culture. The sphere-forming cells were sensitive to treatment with sorafenib, a multikinase inhibitor, that is used for HCC treatment. Further, stattic, an inhibitor of the Stat3 molecule, induced sphere-forming cell death. A combination of sorafenib and stattic had a significantly stronger effect, leading to cell death. These results suggested that HCV infection potentiates CSC generation, and selected drugs can be targeted to efficiently inhibit cell growth. IMPORTANCE HCV infection may develop into HCC as an end-stage liver disease. We focused on understanding the mechanism for the risk of HCC from chronic HCV infection and identified targets for treatment. HCV-infected primary and transformed human hepatocytes (PHH or THH) generated CSC. HCV-induced spheres were highly sensitive to cell death from sorafenib and stattic treatment. Thus, our study is highly significant for HCV-associated HCC, with the potential for developing a target-specific strategy for improved therapies.
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    Electronic ISSN: 1098-5514
    Topics: Medicine
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  • 4
    Publication Date: 2013-06-28
    Description: CD55 limits excessive complement activation on the host cell surface by accelerating the decay of C3 convertases. In this study, we observed that hepatitis C virus (HCV) infection of hepatocytes or HCV core protein expression in transfected hepatocytes upregulated CD55 expression at the mRNA and protein levels. Further analysis suggested that the HCV core protein or full-length (FL) genome enhanced CD55 promoter activity in a luciferase-based assay, which was further augmented in the presence of interleukin-6. Mutation of the CREB or SP-1 binding site on the CD55 promoter impaired HCV core protein-mediated upregulation of CD55. HCV-infected or core protein-transfected Huh7.5 cells displayed greater viability in the presence of CD81 and CD55 antibodies and complement. Biochemical analysis revealed that CD55 was associated with cell culture-grown HCV after purification by sucrose density gradient ultracentrifugation. Consistent with this, a polyclonal antibody to CD55 captured cell culture-grown HCV. Blocking antibodies against CD55 or virus envelope glycoproteins in the presence of normal human serum as a source of complement inhibited HCV infection. The inhibition was enhanced in the presence of both the antibodies and serum complement. Collectively, these results suggest that HCV induces and associates with a negative regulator of the complement pathway, a likely mechanism for immune evasion.
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    Electronic ISSN: 1098-5514
    Topics: Medicine
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  • 5
    Publication Date: 2017-04-29
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  • 6
    Publication Date: 2017-03-01
    Description: Fibrogenic pathways in the liver are principally regulated by activation of hepatic stellate cells (HSC). Fibrosis is associated with chronic hepatitis C virus (HCV) infection, although the mechanism is poorly understood. HSC comprise the major population of nonparenchymal cells in the liver. Since HCV does not replicate in HSC, we hypothesized that exosomes secreted from HCV-infected hepatocytes activate HSC. Primary or immortalized human hepatic stellate (LX2) cells were exposed to exosomes derived from HCV-infected hepatocytes (HCV-exo), and the expression of fibrosis-related genes was examined. Our results demonstrated that HCV-exo internalized to HSC and increased the expression of profibrotic markers. Further analysis suggested that HCV-exo carry miR-19a and target SOCS3 in HSC, which in turn activates the STAT3-mediated transforming growth factor β (TGF-β) signaling pathway and enhances fibrosis marker genes. The higher expression of miR-19a in exosomes was also observed from HCV-infected hepatocytes and in sera of chronic HCV patients with fibrosis compared to healthy volunteers and non-HCV-related liver disease patients with fibrosis. Together, our results demonstrated that miR-19a carried through the exosomes from HCV-infected hepatocytes activates HSC by modulating the SOCS-STAT3 axis. Our results implicated a novel mechanism of exosome-mediated intercellular communication in the activation of HSC for liver fibrosis in HCV infection. IMPORTANCE HCV-associated liver fibrosis is a critical step for end-stage liver disease progression. However, the molecular mechanisms for hepatic stellate-cell activation by HCV-infected hepatocytes are underexplored. Here, we provide a role for miR-19a carried through the exosomes in intercellular communication between HCV-infected hepatocytes and HSC in fibrogenic activation. Furthermore, we demonstrate the role of exosomal miR-19a in activation of the STAT3–TGF-β pathway in HSC. This study contributes to the understanding of intercellular communication in the pathogenesis of liver disease during HCV infection.
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  • 7
    Publication Date: 2016-01-16
    Description: Hepatitis C virus (HCV) is a major cause of chronic hepatitis, liver cirrhosis, and hepatocellular carcinoma in humans. We showed previously that HCV induces autophagy for viral persistence by preventing the innate immune response. Knockdown of autophagy reduces extracellular HCV release, although the precise mechanism remains unknown. In this study, we observed that knockdown of autophagy genes enhances intracellular HCV RNA and accumulates infectious virus particles in cells. Since HCV release is linked with the exosomal pathway, we examined whether autophagy proteins associate with exosomes in HCV-infected cells. We observed an association between HCV and the exosomal marker CD63 in autophagy knockdown cells. Subsequently, we observed that levels of extracellular infectious HCV were significantly lower in exosomes released from autophagy knockdown cells. To understand the mechanism for reduced extracellular infectious HCV in the exosome, we observed that an interferon (IFN)-stimulated BST-2 gene is upregulated in autophagy knockdown cells and associated with the exosome marker CD63, which may inhibit HCV assembly or release. Taken together, our results suggest a novel mechanism involving autophagy and exosome-mediated HCV release from infected hepatocytes. IMPORTANCE Autophagy plays an important role in HCV pathogenesis. Autophagy suppresses the innate immune response and promotes survival of virus-infected hepatocytes. The present study examined the role of autophagy in secretion of infectious HCV from hepatocytes. Autophagy promoted HCV trafficking from late endosomes to lysosomes, thus providing a link with the exosome. Inhibition of HCV-induced autophagy could be used as a strategy to block exosome-mediated virus transmission.
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  • 8
    Publication Date: 2012-08-24
    Description: We have examined the underlying mechanism of hepatitis C virus (HCV)-mediated IFITM1 regulation. IFITM1 is a potential target of miR-130a. Our results demonstrated that miR-130a expression was significantly higher in HCV-infected hepatocytes and liver biopsy specimens than in controls. Introduction of anti-miR-130a in hepatocytes increased IFITM1 expression. Hepatocytes stably expressing IFITM1 reduced HCV replication. Together, these results suggested that HCV infection of hepatocytes upregulates miR-130a and that use of anti-miR-130a may have potential for restriction of HCV replication.
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  • 9
    Publication Date: 2012-07-28
    Description: Hepatitis C virus (HCV) induces autophagosome formation in infected human hepatocytes. We have previously reported that HCV exploits autophagic machinery in favor of virus growth and survival in host cells (S. Shrivastava et al., Hepatology 53: 406–414, 2011); however, the mechanisms for autophagy induction is poorly understood. In the present study, we observed that HCV infection transcriptionally upregulates Beclin1, which forms complex with Vps34, the class III phosphatidylinositol 3-kinase, as a first step for autophagy initiation. Although Bcl-2 has an anti-autophagy effect by its association with Beclin1 in nutrient-deprived cells, our studies revealed that HCV-mediated autophagy occurs independent of Beclin1–Bcl-2 dissociation. Mammalian target of rapamycin (mTOR) is a positive regulator of cell growth and is recognized as an inhibitor of autophagy induction. Our results demonstrated that HCV infection enhances phospho-mTOR expression and its downstream target 4EBP1 activation, suggesting that mTOR is not a negative regulator of HCV-induced autophagy. On the other hand, HCV infection in autophagy-impaired cells reduced phospho-mTOR, mTOR, and phospho-4EBP1 expression. Together, these results suggested that HCV induces autophagy by upregulating Beclin1 and activates mTOR signaling pathway, which in turn may promote hepatocyte growth.
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  • 10
    Publication Date: 2013-10-18
    Description: Hepatitis C virus (HCV)-mediated chronic liver disease is a global health problem, and inflammation is believed to be an important player in disease pathogenesis. HCV infection often leads to severe fibrosis/cirrhosis and hepatocellular carcinoma, although the mechanisms for advancement of disease are not fully understood. The proinflammatory cytokines interleukin-1β (IL-1β) and IL-18 have critical roles in establishment of inflammation. In this study, we examined induction of IL-1β/IL-18 secretion following HCV infection. Our results demonstrated that monocyte-derived human macrophages (THP-1) incubated with cell culture-grown HCV enhance the secretion of IL-1β/IL-18 into culture supernatants. A similar cytokine release was also observed for peripheral blood mononuclear cell (PBMC)-derived primary human macrophages and Kupffer cells (liver-resident macrophages) upon incubation with HCV. THP-1 cells incubated with HCV led to caspase-1 activation and release of proinflammatory cytokines. Subsequent studies demonstrated that HCV induces pro-IL-1β and pro-IL-18 synthesis via the NF-B signaling pathway in macrophages. Furthermore, introduction of HCV viroporin p7 RNA into THP-1 cells was sufficient to cause IL-1β secretion. Together, our results suggested that human macrophages exposed to HCV induce IL-1β and IL-18 secretion, which may play a role in hepatic inflammation.
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    Topics: Medicine
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