Displaying publications 1 - 20 of 106 in total

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  1. Azmi AN, Tan SS, Mohamed R
    World J Gastroenterol, 2014 Sep 14;20(34):12045-55.
    PMID: 25232242 DOI: 10.3748/wjg.v20.i34.12045
    The natural history of chronic hepatitis B is characterized by different phases of infection, and patients may evolve from one phase to another or may revert to a previous phase. The hepatitis B e antigen (HBeAg)-negative form is the predominant infection worldwide, which consists of individuals with a range of viral replication and liver disease severity. Although alanine transaminase (ALT) remains the most accessible test available to clinicians for monitoring the liver disease status, further evaluations are required for some patients to assess if treatment is warranted. Guidance from practice guidelines together with thorough investigations and classifications of patients ensure recognition of who needs which level of care. This article aims to assist physicians in the assessment of HBeAg-negative individuals using liver biopsy or non-invasive tools such as hepatitis B s antigen quantification and transient elastography in addition to ALT and hepatitis B virus DNA, to identify who will remain stable, who will reactivate or at risk of disease progression hence will benefit from timely initiation of anti-viral therapy.
    Matched MeSH terms: Hepatitis B virus/drug effects*; Hepatitis B virus/immunology; Hepatitis B virus/pathogenicity
  2. Tan WS, Ho KL
    World J Gastroenterol, 2014 Sep 7;20(33):11650-70.
    PMID: 25206271 DOI: 10.3748/wjg.v20.i33.11650
    Hepatitis B virus (HBV) has killed countless lives in human history. The invention of HBV vaccines in the 20(th) century has reduced significantly the rate of the viral infection. However, currently there is no effective treatment for chronic HBV carriers. Newly emerging vaccine escape mutants and drug resistant strains have complicated the viral eradication program. The entire world is now facing a new threat of HBV and human immunodeficiency virus co-infection. Could phage display provide solutions to these life-threatening problems? This article reviews critically and comprehensively the innovative and potential applications of phage display in the development of vaccines, therapeutic agents, diagnostic reagents, as well as gene and drug delivery systems to combat HBV. The application of phage display in epitope mapping of HBV antigens is also discussed in detail. Although this review mainly focuses on HBV, the innovative applications of phage display could also be extended to other infectious diseases.
    Matched MeSH terms: Hepatitis B virus/drug effects*; Hepatitis B virus/genetics; Hepatitis B virus/immunology; Hepatitis B virus/pathogenicity
  3. Raihan R, Akbar SMF, Al Mahtab M, Khan MSI, Tabassum S, Tee KK, et al.
    Viral Immunol, 2020 09;33(7):530-534.
    PMID: 32513066 DOI: 10.1089/vim.2019.0198
    Hepatitis B virus (HBV) is a noncytopathic virus and billions of HBV-infected patients live uneventful lives and do not suffer from notable liver damage. However, HBV also causes progressive liver diseases characterized by hepatic inflammation, hepatic fibrosis, and liver cancer in millions of HBV-infected patients. The goal of this study was to evaluate the role of mutant HBV in HBV pathogenesis. In a cohort of 360 chronic HBV-infected patients, mutations at T1762/A1764 of HBV genome were detected in most of the patients with HBV-induced liver cirrhosis and hepatocellular carcinoma. To explore if mutations at T1762/A1764 of HBV genome has any role in progressive liver disease, peripheral blood mononuclear cells (PBMCs) and antigen-presenting dendritic cells (DCs) were isolated from five chronic hepatitis B (CHB) patients with mutations at T1762/A1764 and five comparable patients of CHB without mutations at T1762/A1764. DCs were pulsed with hepatitis B surface antigen (HBsAg). The levels of cytokines produced by PBMCs and DCs as well as nitrite production by DCs were evaluated. Significantly higher levels of interleukin-12, tumor necrosis factor-alpha, interferon-gamma, and transforming growth factor-beta were detected in cultures of PBMCs, DCs, and HBsAg-pulsed DCs from CHB patients with mutations at T1762/A1764 compared with those without mutations (p 
    Matched MeSH terms: Hepatitis B virus/genetics*
  4. Ninyio NN, Ho KL, Ong HK, Yong CY, Chee HY, Hamid M, et al.
    Vaccines (Basel), 2020 Jun 04;8(2).
    PMID: 32512923 DOI: 10.3390/vaccines8020275
    Chimeric virus-like particles (VLPs) have been widely exploited for various purposes including their use as vaccine candidates, particularly due to their ability to induce stronger immune responses than VLPs consisting of single viral proteins. In the present study, VLPs of the Macrobrachium rosenbergii nodavirus (MrNV) capsid protein (Nc) displaying the hepatitis B virus "a" determinant (aD) were produced in Spodoptera frugiperda (Sf9) insect cells. BALB/c mice immunised with the purified chimeric Nc-aD VLPs elicited a sustained titre of anti-aD antibody, which was significantly higher than that elicited by a commercially available hepatitis B vaccine and Escherichia coli-produced Nc-aD VLPs. Immunophenotyping showed that the Sf9-produced Nc-aD VLPs induced proliferation of cytotoxic T-lymphocytes and NK1.1 natural killer cells. Furthermore, enzyme-linked immunospot (ELISPOT)analysis showed the presence of antibody-secreting memory B cells in the mice splenocytes stimulated with the synthetic aD peptide. The significant humoral, natural killer cell and memory B cell immune responses induced by the Sf9-produced Nc-aD VLPs suggest that they present good prospects for use as a hepatitis B vaccine candidate.
    Matched MeSH terms: Hepatitis B virus
  5. Jo HS, Khan JF, Han JH, Yu YD, Kim DS
    Transplant Proc, 2021 Dec;53(10):3016-3021.
    PMID: 34740450 DOI: 10.1016/j.transproceed.2021.09.038
    BACKGROUND: Hepatitis B immunoglobulin (HBIG) and oral nucleoside/nucleotide analogs have been the mainstay of hepatitis B virus (HBV) prophylaxis after liver transplantation. However, long-term HBIG administration could have disadvantages, such as an increase in medical costs and the development of mutant HBV strains. This study aimed to investigate the safety and efficacy of HBV vaccination after the withdrawal of HBIG after liver transplantation.

    METHODS: This prospective open-label single-arm observational clinical trial enrolled 41 patients who underwent liver transplantation between 2010 and 2016 because of a condition related to chronic HBV infection. At the time of enrollment, all patients had taken entecavir and discontinued HBIG administration. When hepatitis B surface antibody titer was undetectable after the withdrawal of HBIG, a recombinant HBV vaccine was injected intramuscularly at month 0, 1, and 6.

    RESULTS: After excluding 5 patients who dropped out and 2 patients who had a persistent hepatitis B surface antibody titer, 9 (26.5%) of 34 patients had a positive vaccination response. The median hepatitis B surface antibody titer at seroconversion was 86 (12-1000) IU/L, and those at the end of follow-up were 216 (30-1000) IU/L. No patients experienced HBV recurrence during the study period. Sex (female, odds ratio 32.91 [1.83-592.54], P = .018) and the dosing interval of HBIG before withdrawal (≥90 days, 16.21 [1.21-217.31], P = .035) were independent contributing factors for positive response to the vaccination.

    CONCLUSION: HBV vaccination still deserves consideration as active immunoprophylaxis after liver transplantation because it could provide added immunity to nucleoside/nucleotide analogs monotherapy with excellent cost-effectiveness.

    Matched MeSH terms: Hepatitis B virus/genetics
  6. Yousuf R, Rapiaah M, Ahmed SA, Rosline H, Salam A, Selamah S, et al.
    PMID: 18613548
    The objective of this study was to determine the prevalence and trends in hepatitis B infection among blood donors attending the Transfusion Medicine Unit at the Hospital Universiti Sains Malaysia, Kelantan, Malaysia. A retrospective study was carried out by reviewing the results of HBsAg among blood donors for the years 2000 to 2004. During this period, 44,658 blood donors were studied. We noted that there was a significant difference in the prevalence of hepatitis B infection between regular and first time donors. There was also a decreasing trend noticed in both study groups. The mean prevalence was significantly different between first time (1.83%) and regular donors (0.45%) (p < 0.005). There is a need to improve public awareness programs to lower the incidence of hepatitis B infection in the general population and consequently first time blood donors. Future studies are also required to determine the trends and outcomes of these programs.
    Matched MeSH terms: Hepatitis B virus*
  7. Ng KP, Ngeow YF, Rozainah K, Rosmawati M
    Med J Malaysia, 2013 Apr;68(2):144-7.
    PMID: 23629561 MyJurnal
    A nationwide HBV vaccination for neonates in the Expanded Programme on Immunization (EPI) was implemented in Malaysia in 1989. The objective of this study was to investigate the prevalence of HBsAg, anti-HBs and anti-HBc among the new student intakes in the Faculties of Medicine and Dentistry, University of Malaya from 2005 to 2011.
    Matched MeSH terms: Hepatitis B virus
  8. Leung N
    Med J Malaysia, 2005 Jul;60 Suppl B:63-6.
    PMID: 16108176
    The association of hepatitis B virus (HBV) infection and liver cancer is well documented in epidemiological study. Patients with chronic hepatitis B have increased risk of hepatocelluar carcinoma (HCC), in particular those with active liver disease and cirrhosis. The incidence of HCC increases with age and is more common among male patients. The introduction of universal HBV vaccination program for the newborn in endemic regions has started to show beneficial impact. Taiwan introduced this program two decades ago and the incidence of liver cancer among infants and young children have declined significantly. The carcinogenic events leading to HCC are under intense research. A number of hypotheses have been proposed. HBV is not directly hepatotoxic but its interaction with the host immune system creates opportunity for HBV DNA integration into the host genome. One of the main foci of research is the HBX-encoded X protein. Its integration and protein expression impose alteration in cell proliferation cycle and apoptosis process. Many other factors may be involved including viral-induced alterations in p53 and telemerase, HBV genotypes, co-infection with HCV or delta agents, patient's lifestyle such as smoking, alcohol excesses, and genetic factors of the host patient. The processes of necroinflammation, cell proliferation and fibrosis facilitate the initial carcinogenic development. HCC surveillance with tumor markers such as alpha-foetal protein, decarboxylated prothrombin, in conjunction with imaging techniques has identified early small HCC that is amenable to curative therapy. Viral load has been correlated with increase risk of HCC. The available anti-viral agents have demonstrated clinical benefit among those with maintained and sustained response. Interferon and lamivudine therapy have demonstrated reduction of HCC among responders. However, they only constitute a minority proportion of treated patients. The mainstay of prevention should lie in prevention of HBV infection and early effective therapy of chronic hepatitis B infection.
    Matched MeSH terms: Hepatitis B virus/immunology
  9. Locarnini S
    Med J Malaysia, 2005 Jul;60 Suppl B:41-51.
    PMID: 16108173
    Matched MeSH terms: Hepatitis B virus/drug effects; Hepatitis B virus/genetics; Hepatitis B virus/immunology*
  10. Hoo CZ, Wan Abdullah WZ, Omar H, Tan SS
    Med J Malaysia, 2023 Mar;78(2):234-240.
    PMID: 36988536
    INTRODUCTION: Worldwide, around 296 million people have hepatitis B virus (HBV) infection, most commonly transmitted from mother-to-child. Global Health Sector Strategy on Viral Hepatitis (GHSSVH) was introduced in May 2016, calling for elimination of viral hepatitis by 2030. This study aims to compare practice in a tertiary liver centre before and after GHSSVH introduction for prevention of mother-to-child transmission (MTCT).

    MATERIALS AND METHODS: This retrospective cohort study was performed in a tertiary referral liver centre in Malaysia, using data from electronic medical record from January 2015 to December 2019. A total of 1457 medical records of female with HBV infection were screened. The inclusion criteria of the study were pregnant women with HBsAg positive or known to have HBV infection during the study period. We excluded patients with co-infections of other types of viral hepatitis or human immunodeficiency virus, concurrent liver diseases (e.g.: autoimmune hepatitis, Wilson’s disease), previous organ transplant and malignancy—except for hepatocellular carcinoma (HCC).

    RESULTS: This study included 117 pregnancies and 21/117 (17.9%) were on antiviral therapy (AVT) for HBV. In 2017– 2019, 13/18 (72.2%) of those with HBV DNA >200,000IU/ml were on AVT, compared to 5/9 (55.6%) for 2015–2016, indicating 58% (95% CI −63% to 568%) higher odds of being on AVT in post GHSSVH group after accounting for HBV DNA.

    CONCLUSION: Uptake of maternal AVT for the prevention of MTCT shows an increased trend since the introduction of GHSSVH, with room for improvement.

    Matched MeSH terms: Hepatitis B virus*
  11. Rasuli R, Mohamad M, Yaacob SS
    Med J Malaysia, 2023 Dec;78(7):883-889.
    PMID: 38159922
    INTRODUCTION: Despite substantial progress in reducing hepatitis B prevalence in the general population, the indigenous population in Malaysia continues to face a significant burden of infection, with high seroprevalence rates. It is hypothesised that transmission patterns differ between the indigenous and non-indigenous populations. This study aimed to compare key risk factors for hepatitis B transmission in indigenous and non-indigenous cases.

    MATERIALS AND METHODS: This is a comparative crosssectional study using secondary data from the eNotifikasi system and hepatitis B case investigation forms between 2018 and 2022 from four district health offices in Pahang, Malaysia. Demographic data, hepatitis B vaccination status and risk factors were assessed. Data analysis employed were independent chi-squared tests, t-tests and binary logistic regression.

    RESULTS: The study included 285 cases (141 indigenous and 145 non-indigenous). Among the indigenous cases, 72.3% were unvaccinated and 59.6% reported a history of infected mother, followed by percutaneous exposure, multiple sexual partners, and sharing syringe. The odds for those with a history of an infected mother being indigenous group is 2.5 times (95% CI: 1.4-4.4) compared to those with a history of an infected mother being non-indigenous group.

    CONCLUSION: Significant difference exists in hepatitis B risk factors between indigenous and non-indigenous populations. The main risk factor for indigenous community is history of infected mother. Thus, the necessity of incorporating hepatitis B screening into the current practice of antenatal HIV screening, specifically targeting the indigenous community, should be given consideration.

    Matched MeSH terms: Hepatitis B virus
  12. Wilkinson IE
    Med J Aust, 1992 May 18;156(10):741.
    PMID: 1535682
    Matched MeSH terms: Hepatitis B virus/immunology*
  13. Lim CK, Tan JT, Ravichandran A, Chan YC, Ton SH
    Malays J Pathol, 2007 Dec;29(2):79-90.
    PMID: 19108399 MyJurnal
    Hepatitis B virus (HBV) is classified into eight genotypes (A to H). In this study, three genotyping methods were compared for their sensitivity and accuracy, namely PCR-RFLP on the S region, PCR-RFLP on the pre-S region and nested PCR with type specific primers. Sixty HBV samples from infected sera were genotyped. The nested PCR with type specific primers was found to be the most sensitive and produced substantial numbers of co-infections by genotypes B and C. The sensitivities for both PCR-RFLP methods were lower and did not reveal co-infections. Generally, the three methods produced consistent genotyping results in samples infected by single genotypes but for co-infections by genotypes B and C, the two PCR-RFLP methods yielded only single genotypic results. For the cases of single genotypic infections, genotypes ascertained by sequencing were in concordance across all three methods. However, when co-infections occurred, PCR analysis on clones revealed only single genotypic infections.
    Matched MeSH terms: Hepatitis B virus/genetics*
  14. Yap SF
    Malays J Pathol, 2004 Jun;26(1):1-12.
    PMID: 16190102
    "Parenteral" or "serum" hepatitis is known to have afflicted man for centuries. However, it was not until the mid-1960s that the causative agent of this infection, the hepatitis B virus, was discovered. Since then, the biology and the replication strategy of the virus, and the clinical features and the epidemiology of the hepatitis B infection have been determined. Knowledge about the virus and the infection it causes led to the development of firstly, a plasma-derived vaccine and later a recombinant vaccine for the prevention of the infection. Integration of the hepatitis B vaccine into newborn vaccination programmes on a worldwide basis represents a major step in the effort to eliminate this infectious disease and its complications. Laboratory tests are available for the diagnosis and monitoring of the disease. Therapies have been developed to halt the progress of the chronic infection in affected individuals. While these developments have resulted in a decrease of the frequency of infection in many countries, particularly those that have implemented universal immunization of newborns, the chronic infection remains a significant global problem. Worldwide, over 300 million individuals are infected and each year, an estimated 1 million persons die from chronic complications of the disease including hepatocellular carcinoma and hepatic failure. The therapies currently available result in elimination of the virus in only a relatively small proportion of subjects and carry with it serious side effects. Geopolitical, economic and other factors hinder the vision of elimination of the infection through immunization programmes. Nevertheless, work continues to clarify further the underlying pathological mechanism of the infection, the host and viral factors that promote elimination or persistence of the virus in the human host. It is hoped that such investigations will reveal viral targets for the design of newer and potentially more effective drugs to treat the infection.
    Matched MeSH terms: Hepatitis B virus/genetics; Hepatitis B virus/immunology; Hepatitis B virus/ultrastructure
  15. Yap SF, Wong NW, Goh KL
    Malays J Pathol, 1994 Jun;16(1):57-62.
    PMID: 16329577
    The relationship between serum Hepatitis B virus DNA (HBV-DNA) and the Hepatitis B e-antigen/ anti-Hepatitis Be (HBeAg/anti-HBe) serological status in Malaysians was studied. 212 cases of asymptomatic HBV carriers were recruited for this study. 92 cases were positive for the HBeAg at the point of recruitment. 85 (92.4%) of these patients tested positive for HBV-DNA, of whom 55 (64.7%) had levels over 100pg/ml of serum. Three of the remaining 7 HBeAg positive cases who were negative for HBV-DNA subsequently seroconverted. The other 4 cases remained negative for HBV-DNA for periods of 6-12 months. Out of 113 cases who were anti-HBe positive, 12 (10.6%) gave a positive HBV-DNA result. 2 of these 12 patients were recent seroconverters; the remaining cases had transiently increased viral replicative activity which later subsided. 7 out of the 212 carriers were in the e-window period; all 7 tested negative for HBV-DNA. Our data confirm a high frequency of HBV-DNA in HBeAg positive carriers and a negative correlation between HBV-DNA and anti-HBe. An atypical profile of anti-HBe associated with HBV-DNA was observed in 10.6% of the carriers. An inverse relationship between serum HBV-DNA levels and age was also observed.
    Matched MeSH terms: Hepatitis B virus/genetics; Hepatitis B virus/immunology; Hepatitis B virus/isolation & purification*
  16. Yap SF
    Malays J Pathol, 1994 Jun;16(1):3-6.
    PMID: 16329567
    Chronic hepatitis B virus (HBV) infection constitutes a major public health problem particularly in developing countries in East Asia, South-East Asia, the Pacific Basin and Africa. In Malaysia, a developing nation in the South East Asian region, the chronic HBV carrier rate varies between < 1% to about 10% depending on the ethnic group studied. The highest frequency is seen among the Chinese, followed by the Malays and lastly the Indians, with a male preponderance of between 2 : 1 and 3 : 1. Exposure to the virus among the adult population is estimated to be about 15%, 26% and 36% among the Indians, Malays and Chinese respectively. Serological study of adult chronic HBV carriers showed a frequency of HBe antigenemia of about 35%, with a significant decreasing trend with age. HBV DNA status generally correlated with the HBe status. An atypical profile of anti-HBe associated with serum HBV DNA is found in some carriers; in most instances, this is related to seroconversion from HBe antigenemia to anti-HBe. Chronic complications of HBV infection include the development of hepatocellular carcinoma (HCC), the occurrence of which closely parallel that of HBsAg carrier rate. In Malaysia, HCC is the third most common malignant neoplasm and among the 10 leading causes of death. About 80% of our HCC cases are HBV associated. All 3 ethnic groups are afflicted, the highest frequency being among the Chinese. Males show a disproportionate risk with an odds ratio of 3.93 (p < 0.0001).
    Matched MeSH terms: Hepatitis B virus/immunology
  17. Goh KL
    Malays J Med Sci, 2019 Mar;26(2):18-29.
    PMID: 31447605 DOI: 10.21315/mjms2019.26.2.3
    The landscape of liver diseases in Malaysia has changed dramatically since the time of Professor Balasegaram Manickavasagar-an eminent surgeon in the 1960s. The most significant discoveries in hepatology have been that of hepatitis B virus in 1963 and hepatitis C virus in 1989, which have both been shown to be predominantly blood borne diseases. Hepatitis B and C infections result in long term carrier state and a high propensity to develop liver cirrhosis and cancer. Hepatitis B is the most common cause of liver cirrhosis and cancer in Malaysia. Blood bank screening and public health preventive measures have reduced the disease burden significantly and an effective vaccination for hepatitis B is now incorporated in our National Immunisation Programme. Although no vaccine is available for hepatitis C, highly effective eradication therapies were introduced in 2011. These agents will significantly change the disease scenario across the world. A "new" disease was described in 1980, by Ludwig et al.-non-alcoholic fatty liver (NAFLD) disease. With the global epidemic of obesity and diabetes mellitus, NAFLD is set to increase exponentially across the world including in Malaysia. It will be the most important liver disease in the future, replacing hepatitis B and C infections.
    Matched MeSH terms: Hepatitis B virus
  18. Tan WS
    J Gen Appl Microbiol, 2002 Apr;48(2):103-7.
    PMID: 12469306
    The long surface antigen (L-HBsAg) of hepatitis B virus (HBV) plays a central role in the production of infectious virions. During HBV morphogenesis, both the PreS and S domains of L-HBsAg form docking sites for the viral nucleocapsids. Thus, a compound that disrupts the interaction between the L-HBsAg and nucleocapsids could serve as a therapeutic agent against the virus based upon inhibition of morphogenesis. Synthetic peptides correspond to the binding sites in L-HBsAg inhibited the association of L-HBsAg with core antigen (HBcAg). A synthetic peptide carrying the epitope for a monoclonal antibody to the PreS1 domain competed weakly with L-HBsAg for HBcAg, but peptides corresponding to a linear sequence at the tip of the nucleocapsid spike did not, showing that the competing peptide does not resemble the tip of the spike.
    Matched MeSH terms: Hepatitis B virus/drug effects*; Hepatitis B virus/physiology
  19. Hasmoni SS, Yusoff K, Tan WS
    J Gen Appl Microbiol, 2005 Apr;51(2):125-31.
    PMID: 15942873
    The nucleocapsids of hepatitis B virus (HBV) are made of 180 or 240 subunits of core proteins or known as core antigens (HBcAg). A fusion bacteriophage bearing the WSFFSNI sequence that interacts tightly to HBcAg was employed as a diagnostic reagent for the detection of the antigen using the phage-enzyme-linked immunosorbent (phage-ELISA), dot blot and immunoprecipitation assays. The results from phage-ELISA and dot blot assay showed that as low as 10 ng of HBcAg can be detected optimally by 1.0x10(12) pfu/ml fusion M13 bacteriophage. The sensitivity of the dot blot assay corresponds with that of the phage-ELISA. HBcAg in HBV positive serum samples can also be detected using the fusion phage via the phage-ELISA and phage-dot blot assay. The phage cross-linked to cyanogen bromide (CNBr) activated agarose can also be used to precipitate HBcAg in bacterial lysate. The optimum amount of phage needed for cross-linking to 1 g of agarose is about 7.0x10(6) pfu/ml which could also precipitate purified and unpurified HBcAg in bacterial lysate. This study demonstrates the potential of fusion bacteriophage bearing the sequence WSFFSNI as a diagnostic reagent and a ligand for the detection and purification of HBcAg respectively.
    Matched MeSH terms: Hepatitis B virus/isolation & purification*
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