Regensburg, Univ., Diss., 2009.

Thesis (Ph. D.)--University of Hong Kong, 2005. / Title proper from title frame. Also available in printed format.

Hepatitis B virus infection (HBV) is an important health problem worldwide, with a significant rate of chronic infection, which can lead to cirrhosis and hepatocellular carcinoma (HCC). Increased age is an important determinant of progression to cirrhosis and HCC, possibly because age is a crude measure of the duration of HBV infection. Increasing age is associated with changes in liver structure, blood flow and function and with reduced response to injury, impaired regeneration and increased mortality in acute liver disease. Age has been identified as a co‐factor in several chronic liver diseases including chronic hepatitis C infection (HCV). Available evidence suggests differential ageing of various intrahepatic cell types in different liver diseases and the ageing process may be more complex in the liver than originally thought. Telomeres are DNA structures located at the end of each chromosome, which protect the underlying coding DNA from breaks and fusions and shorten with increasing age. Both DNA damage and cell proliferation lead to progressive telomere shortening, which ultimately leads to cell cycle arrest and a state of replicative senescence. Persistent HCV and HBV infections lead to cell cycle arrest, providing a favourable environment for viral replication. Evidence suggests that progressive telomere shortening occurs with advancing stage of liver disease in HBV and specifically from cirrhosis through large cell dysplasia to small cell dysplasia and to HCC. Whether cell cycle arrest leads to a senescent‐like state or whether this is the result of oxidative stress is unknown. Unpublished data using cell cycle phase markers in chronic HBV infection reveal that hepatocytes, which support HBV replication, are arrested in G1, which is mediated by hepatocyte p21 expression. I hypothesise that: 1. In normal liver tissue, different cell types age at different rates and this is altered during disease; 2. Hepatocyte senescence plays a significant role in the natural course of chronic HBV infection and underlies HBV antigen expression. I developed and optimised large volume Q‐FISH methodology to measure telomere length and nuclear size in a variety of intrahepatic cell lineages. In normal liver tissue, cholangiocytes had longer telomeres compared with all other intrahepatic lineages over a wide age range. Hepatocytes did not show any age‐related telomere shortening, in contrast to Kupffer and hepatic stellate cells. In chronic HBV infection, all hepatocytes had shortened telomeres when compared to age and sex‐matched controls consistent with accelerated ageing. HBV replication was confined to those hepatocytes with longer telomeres, suggesting that HBV entry or replication is less efficient in older hepatocytes and compatible with the fall in serum HBV DNA and HBsAg titre seen with advancing age. There may be two populations of hepatocytes in chronic HBV infection; hepatocytes that are growth arrested with short telomeres not supporting HBV replication and biologically 'younger' hepatocytes with longer telomeres that do support HBV replication. The change in cellular HBV antigen localisation with disease progression is also explained by age related changes in HBV expression. Nuclear Hepatitis B core antigen expression (HBcAg), characteristic of the early immune tolerant phase of infection, was associated with the longest telomeres, while cytoplasmic HBcAg expression was associated with shorter telomeres. Furthermore, the total number of hepatocyte telomeres fell with increasing fibrosis stage. Hepatocyte nuclear size, a marker of senescence, increased as HBcAg expression shifted from nucleus to cytoplasm; and p21, another senescence marker, never co‐localised with HBcAg expression. These results suggest that the location and production of HBV antigens are related to increased functional hepatocyte age and the onset of cellular senescence.

No description available.

Mathematical modeling of biological systems has improved the knowledge of scientists for many years. In virology, particularly in the study of hepatitis B virus, mathematical models were used to explain interactions between hepatitis B virus and the human host in the absence and presence of interventions such as drug therapy and vaccines. This thesis seeks to explain the role of e-Antigen, a particle produced by hepatitis B virus, in the pathogenesis of hepatitis B infection. To accomplish this goal, I will provide biological background as well as previous modeling work on the role of e-Antigen in hepatitis B virus infection, before finally developing a new model adapted specifically for connecting hepatitis B progression with e-Antigen and drug therapy. I will analyze the model both analytically and numerically, fit it to virus data from humans chronically infected with hepatitis B that undergo drug therapy, and draw conclusions about the relation between drugs, immune activation, and loss of e-Antigen. / Master of Science

Gene therapy has shown potential in alleviating a wide range of diseases, ranging from viral infections to autosomal diseases. One of the obstacles to gene therapy reaching its full potential is the inadequacy of methods to deliver therapeutic nucleic sequences. Current delivery of gene therapy entails use of viral and non-viral vectors. Viral vectors are however associated with drawbacks such as potential toxicity, high cost and labour-intensive production. Thus non-viral delivery alternatives are being developed in an attempt to overcome difficulties associated with nucleic acid delivery for gene therapy. Virus-like particles are potentially very useful delivery vehicles as their production is simple and cost effective, the particle surface is amenable to modification and the capsid interior can be altered to accommodate a variety of cargoes. One such particle is the recombinant HBV capsid, which comprises a single species of protein and is tolerant of amino acid substitutions on the surface exposed immunodominant loops. This study aimed to enhance the vector-like properties of the HBV virus-like particle by including amino acid substitutions on the particle surface. These substituted residues in turn provided a conjugation site for tropic and immuno evasive moieties. It was found that lysine substitutions resulted in poor conjugation to the capsid surface, whereas substituted cysteine residues resulted in almost all protein-moiety conjugates forming. In order to introduce lysine and cysteine substitutions, a novel method of cloning into the HBV was generated. In doing so, complicated procedures associated with cloning into the immunodominant loop of the HBV capsid have been alleviated. Ligands containing galactose were utilised on the surface of both the HBV capsid and liposomes to confer hepatotropism. The presence of the galactose moieties on the surface of the HBV capsid prevented indiscriminate cellular uptake in cultured cells, however did not improve hepatotropism. Galactose ligands on the surface of liposomes did improve transfection efficiency, however they required a short linker distance between liposome surface and galactose group. The inclusion of galactose in liposome formulations also provided a means to deliver siRNA to the liver of transgenic HBV mice. It is believed that with alterations to the ligand structure, it is possible to provide HBV capsids with hepatotropism in future experimentation. This study demonstrated that the exposed external surface of the HBV capsid is amenable to convenient conjugation, which potentially facilitates immune evasion and conferring of defined tropism.

by Chan Lik-yuen, Henry. / Thesis (M.D.)--Chinese University of Hong Kong, 2001. / Includes bibliographical references (p. 192-217). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Mode of access: World Wide Web.

In conclusion, two new methods of cccDNA quantitation were developed and validated. The two assays are complementary to each other and may be used in patients with extreme HBV DNA levels. These cccDNA assays should be further validated in larger studies and may become important tests for diagnostic, prognostic and treatment monitoring purposes. / Over 350 million people worldwide suffer from chronic hepatitis B virus (HBV) infection, which leads to many cases of cirrhosis and hepatocellular carcinoma. HBV covalently closed circular DNA (cccDNA) is a critical intracellular replicative intermediate and cannot be eliminated during antiviral therapy. Current methods for cccDNA detection are limited by false positive detection due to the interference by HBV relaxed circular DNA (rcDNA). The tests also have limited sensitivity to detect cccDNA at low concentrations. Hence, we aimed to develop a highly sensitive and highly specific assay for cccDNA detection with wide linear range. / The modified Bowden's assay had the highest intrahepatic cccDNA detection rate (60 positive results out of 61 cases). The detection rate of the modified Bowden's assay is significantly higher than that of the Bowden's assay. On the other hand, the cccDNA detection rate in serum samples was low at 20--27% by all 3 assays. In 5 samples in which cccDNA was undetectable by the Bowden's assay but detectable by the other two assays, a point mutation in the HBV genome was found in the forward primer binding site of the Bowden's assay. This partly explained the false negative results. / The quantification result of cccDNA by the bisulfite conversion assay was significantly lower than that by the Bowden's assay assay (P=0.001) and the modified Bowden's assay (P=0.003). When the total HBV DNA was higher than 107 copies/ml, the serum cccDNA level detected by the bisulfite conversion assay was significantly lower than that detected by the Bowden's assay (P=0.008) and the modified Bowden's assay (P=0.046). When the total HBV DNA is less than 107 copies/ml, there were no significant differences. This suggests that the bisulfite conversion assay was less affected by rcDNA even in samples containing a high viral load. / With this background, two new cccDNA assays were developed and optimized. Bowden's assay was used as a standard to evaluate the performance of new assays. The first new assay (modified Bowden's assay) involved the use of new primers and probes that targeted more conserved regions in the HBV genome. The second assay adopted the bisulfite conversion method, which introduced gene sequence changes into the HBV genome and thereby enhance the specificity of the assay. Capillary sequencing was performed to find mutations in primers and probe range of different assays. / Yu, Ling. / Advisers: Vincent Wai-Sun Wang; Joseph Jao-Yiu Sung. / Source: Dissertation Abstracts International, Volume: 73-06, Section: B, page: . / Thesis (Ph.D.)--Chinese University of Hong Kong, 2011. / Includes bibliographical references (leaves 105-111). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Electronic reproduction. [Ann Arbor, MI] : ProQuest Information and Learning, [201-] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstract also in Chinese.

Ng Wah. / Thesis submitted in: August 2006. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2007. / Includes bibliographical references (leaves 101-113). / Abstracts in English and Chinese. / ABSTRACT --- p.II / 摘要 --- p.IV / ACKNOWLEDGEMENT --- p.VI / TABLE OF CONTENTS --- p.VII / LIST OF TABLES --- p.X / LIST OF FIGURES --- p.XI / ABBREVIATIONS --- p.XII / Chapter Chapter 1 --- Introduction --- p.1 / Chapter 1.1 --- Introduction --- p.2 / Chapter 1.2 --- Etiological Factors of Hepatocellualr Carcinoma (HCC) --- p.4 / Chapter 1.2.1 --- Dietary Aflatoxins --- p.4 / Chapter 1.2.2 --- Liver Cirrhosis --- p.5 / Chapter 1.2.3 --- Alcohol Abuse --- p.6 / Chapter 1.2.4 --- Viral Hepatitis Infection --- p.6 / Chapter 1.3 --- Literature Review on the Investigations of HBV Integrants in HCC --- p.16 / Chapter 1.3.1 --- Affected Host Junctions --- p.17 / Chapter 1.3.2 --- Viral Junctions --- p.18 / Chapter 1.4 --- Restriction Site Polymerase Chain Reaction (RS-PCR) --- p.19 / Chapter 1.5 --- Aims of Thesis --- p.21 / Chapter Chapter 2 --- Materials and Methods --- p.22 / Chapter 2.1 --- Materials --- p.23 / Chapter 2.1.1 --- Chemicals --- p.23 / Chapter 2.1.2 --- Buffers --- p.24 / Chapter 2.1.3 --- Cell Cultures --- p.24 / Chapter 2.1.4 --- Nucleic Acids --- p.24 / Chapter 2.1.5 --- Enzymes --- p.25 / Chapter 2.1.6 --- Equipment --- p.25 / Chapter 2.1.7 --- Software and Web Resources --- p.26 / Chapter 2.2 --- Methods --- p.27 / Chapter 2.2.1 --- DNA Extraction --- p.27 / Chapter 2.2.2 --- RS-PCR --- p.31 / Chapter 2.2.3 --- Sequencing --- p.37 / Chapter 2.2.4 --- Spectral Karyotyping (SKY) --- p.38 / Chapter 2.2.5 --- Fluorescence In situ hybridization --- p.39 / Chapter Chapter 3 --- Investigation of HBV Integration Sites in HCC Cell lines --- p.45 / Chapter 3.1 --- Introduction --- p.46 / Chapter 3.2 --- Materials and Methods --- p.47 / Chapter 3.2.1 --- Cell Lines --- p.47 / Chapter 3.2.2 --- RS-PCR --- p.47 / Chapter 3.2.3 --- Spectral Karyotyping --- p.48 / Chapter 3.2.4 --- Tyramide Signal Amplification for HBV in FISH Analysis --- p.48 / Chapter 3.3 --- Results --- p.51 / Chapter 3.3.1 --- Identification of HBV Integration Sites in Cell Lines --- p.51 / Chapter 3.3.2 --- Evaluation of RSO Primer Efficiency --- p.52 / Chapter 3.3.3 --- SKY and FISH Analysis --- p.53 / Chapter 3.4 --- Discussion --- p.64 / Chapter 3.4.1 --- HBV Insertions in HCC Cell Lines --- p.64 / Chapter 3.4.2 --- Efficacy of RSO Primers --- p.65 / Chapter 3.4.3 --- Investigation of HBV Integration on Chromosomal Rearrangement --- p.65 / Chapter Chapter 4 --- Investigation of Hepatitis B Virus Integration Sites in Primary HCC --- p.67 / Chapter 4.1 --- Introduction --- p.68 / Chapter 4.2 --- Materials and Methods --- p.69 / Chapter 4.2.1 --- Patients --- p.69 / Chapter 4.2.2 --- RS-PCR --- p.70 / Chapter 4.3 --- Results --- p.72 / Chapter 4.3.1 --- HBV Integration Sites in Primary HCC Tumors and Adjacent Non- malignant Liver --- p.72 / Chapter 4.4 --- Discussion --- p.88 / Chapter 4.4.1 --- HBV integration Sites in Primary HCC Tumors and Adjacent Non- malignant Liver --- p.88 / Chapter 4.4.2 --- Summary on HBV Integrants Identified --- p.91 / Chapter Chapter 5 --- Proposed Future Studies --- p.98 / Chapter 5.1 --- Correlation of Structural Aberrations with HBV Integrations --- p.99 / Chapter 5.2 --- Transcriptional Expression Study on the Genes Interrupted by or Located near the Virus Host Junctions --- p.100 / Chapter Chapter 6 --- References --- p.101

Lam Kit. / Thesis submitted in: July 2002. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2004. / Includes bibliographical references (leaves 141-153). / Abstracts in English and Chinese. / Acknowledgment --- p.I / Table of Content --- p.II / List of Tables --- p.VII / List of Figures --- p.IX / Abbreviations --- p.XIV / Abstract --- p.XVI / 論文摘要 --- p.XIX / Chapter CHAPTER 1 --- INTRODUCTION --- p.1 / Chapter 1.1 --- Hepatitis B --- p.1 / Chapter 1.1.1 --- Brief Introduction of HBV --- p.1 / Chapter 1.1.2 --- History of Hepatitis B Virus --- p.2 / Chapter 1.1.3 --- Hepatitis B Virus Infection around the World --- p.4 / Chapter 1.1.4 --- Hepatitis B Virus Infection in Hong Kong --- p.5 / Chapter 1.1.5 --- Hepatitis B Virus Infection in China --- p.7 / Chapter 1.1.5.1 --- Update of HBV Infection in China --- p.7 / Chapter 1.1.5.2 --- Problems in China --- p.7 / Chapter 1.2 --- Hepatitis B Virology --- p.8 / Chapter 1.2.1 --- Hepadnaviridae Family --- p.8 / Chapter 1.2.2 --- HBV Particles Types --- p.9 / Chapter 1.2.3 --- The HBV Genome --- p.10 / Chapter 1.2.4 --- The Life Cycle of HBV --- p.12 / Chapter 1.2.5 --- Hepatitis B Surface Antigen (HBsAg) --- p.17 / Chapter 1.3 --- HBV Transmission --- p.19 / Chapter 1.4 --- HBV Therapy --- p.19 / Chapter 1.5 --- Phyllanthus Species --- p.22 / Chapter 1.6 --- Alexander Cells --- p.26 / Chapter 1.7 --- Objectives --- p.29 / Chapter CHAPTER 2 --- COMPARISONS OF AQUEOUS AND ORGANIC EXTRACTS OF THREE PHYLLANTHUS SPECIES OF THEIR IN VITRO ANTI-HBV EFFECTS --- p.30 / Chapter 2.1 --- Introduction --- p.30 / Chapter 2.2 --- Materials and Methods --- p.30 / Chapter 2.2.1 --- Materials --- p.30 / Chapter 2.2.1.1 --- Phyllanthus species --- p.30 / Chapter 2.2.1.2 --- "Chemicals, Antibodies and Instrument" --- p.31 / Chapter 2.2.2 --- Extraction Methods --- p.32 / Chapter 2.2.2.1 --- Aqueous Extraction --- p.33 / Chapter 2.2.2.2 --- Organic Extraction --- p.33 / Chapter 2.2.3 --- Cell line --- p.33 / Chapter 2.2.4 --- Toxicity of Extracts --- p.34 / Chapter 2.2.5 --- IMx Assay --- p.34 / Chapter 2.2.6 --- Semi-quantitative RT-PCR --- p.35 / Chapter 2.2.6.1 --- RNA Extraction --- p.35 / Chapter 2.2.6.2 --- RT-PCR --- p.36 / Chapter 2.2.7 --- Western Blotting --- p.37 / Chapter 2.2.7.1 --- Preparation of Protein Samples --- p.37 / Chapter 2.2.7.2 --- Sodium Dodecyl Sulfate Polyacrylamide Gel Electrophoresis (SDS-PAGE) --- p.37 / Chapter 2.2.7.3 --- Protein Transfer --- p.38 / Chapter 2.2.7.4 --- Immumnoblotting --- p.39 / Chapter 2.2.7.5 --- Protein Assay --- p.39 / Chapter 2.3 --- Results --- p.40 / Chapter 2.3.1 --- Toxicity of the Extracts --- p.40 / Chapter 2.3.2 --- Effects on HBsAg Secretion and Viral Gene Expression --- p.45 / Chapter 2.3.2 --- Analysis of Intracellular Viral Proteins --- p.58 / Chapter 2.4 --- Discussion --- p.63 / Chapter CHAPTER 3 --- ISOLATION AND CHARACTERIZATION OF ACTIVE COMPONIENT FROM AN ORGANIC EXTRACT OF PHYLLANTHUS URINARIA (GUANGDONG) --- p.68 / Chapter 3.1 --- Introduction --- p.68 / Chapter 3.2 --- Materials and Methods --- p.69 / Chapter 3.2.1 --- Materials --- p.69 / Chapter 3.2.2 --- Methods --- p.70 / Chapter 3.2.2.1 --- Ethanol Extraction --- p.70 / Chapter 3.2.2.2 --- Partitions --- p.70 / Chapter 3.2.2.3 --- Column Purification --- p.71 / Chapter 3.2.2.4 --- Analytical Thin Layer Chromatographic (TLC) --- p.71 / Chapter 3.2.2.5 --- Crystallization --- p.71 / Chapter 3.3 --- Results --- p.72 / Chapter 3.3.1 --- Analysis of Four Fractions after Partitions --- p.72 / Chapter 3.3.2 --- Screening of the Active Fraction after Column Chromatography of Fraction B --- p.76 / Chapter 3.3.3 --- Screening of the Active Fraction after Column Chromatography of Fraction6 --- p.79 / Chapter 3.3.4 --- Crystallization and Identification of the Isolated component --- p.82 / Chapter 3.3.5 --- Study Anti-HBV effects of pheophorbide a --- p.91 / Chapter 3.4 --- Discussion --- p.97 / Chapter CHAPTER 4 --- STUDY OF PRE S I PROMOTER ACTIVITY OF HBV --- p.103 / Chapter 4.1 --- Introduction --- p.103 / Chapter 4.2 --- Materials and Methods --- p.108 / Chapter 4.2.1 --- Materials --- p.108 / Chapter 4.2.2 --- Methods --- p.109 / Chapter 4.2.2.1 --- Cell line --- p.109 / Chapter 4.2.2.2 --- Clonning of Pre SI Promoter from HBV Genome --- p.109 / Chapter 4.2.2.3 --- Gene Clean --- p.110 / Chapter 4.2.2.4 --- Restriction Enzyme Digestion --- p.111 / Chapter 4.2.2.5 --- Synthesis of T-Overhang EcoR V Cut pBluescript® II KS (-) --- p.111 / Chapter 4.2.2.6 --- Ligation --- p.112 / Chapter 4.2.2.7 --- DH5α Competent Cells Preparation --- p.112 / Chapter 4.2.2.8 --- Transformation --- p.113 / Chapter 4.2.2.9 --- Plasmid Purification --- p.113 / Chapter 4.2.2.10 --- Transfection --- p.114 / Chapter 4.2.2.11 --- Luciferase Assay --- p.115 / Chapter 4.3 --- Results --- p.116 / Chapter 4.3.1 --- Cloning of the Pre S I Promoter --- p.116 / Chapter 4.3.2 --- Sequences of the Pre S I Promoter --- p.121 / Chapter 4.3.3 --- Pre S I Promoter Activities in Hep 3B Cell Line --- p.123 / Chapter 4.3.4 --- Effects of Herbal Extracts on Pre S I Promoter --- p.126 / Chapter 4.4 --- Discussion --- p.130 / Chapter CHAPTER 5 --- GENERAL DISCUSSION --- p.134 / REFERENCES --- p.141