Displaying publications 41 - 60 of 106 in total

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  1. Hudu SA, Harmal NS, Saeed MI, Alshrari AS, Malik YA, Niazlin MT, et al.
    Eur J Clin Microbiol Infect Dis, 2015 Jul;34(7):1349-59.
    PMID: 25792010 DOI: 10.1007/s10096-015-2358-1
    Hepatitis B virus surface mutants are of enormous importance because they are capable of escaping detection by serology and can infect both vaccinated and unvaccinated populations, thus putting the whole population at risk. This study aimed to detect and characterise hepatitis B-escaped mutants among blood donors and vaccinees. One thousand serum samples were collected for this study from blood donors and vaccinees. Hepatitis B surface antigen, antibodies and core antibodies were tested using a commercial enzyme-linked immunosorbent assay (ELISA) kit. DNA detection was performed via nested polymerase chain reaction (PCR), and the S gene was sequenced and analysed using bioinformatics. Of the 1,000 samples that were screened, 5.5% (55/1,000) were found to be HBsAg-negative and anti-HBc- and HBV DNA-positive. All 55 isolates were found to belong to genotype B. Several mutations were found across all the sequences from synonymous and non-synonymous mutations, with the most nucleotide mutations occurring at position 342, where adenine was replaced by guanine, and cytosine at position 46 was replaced by adenine in 96.4% and 98% of the isolates, respectively. Mutation at position 16 of the amino acid sequence was found to be common to all the Malaysian isolates, with 85.7% of the mutations occurring outside the major hydrophilic region. This study revealed a prevalence of 5.5% for hepatitis B-escaped mutations among blood donors and vaccinated undergraduates, with the most common mutation being found at position 16, where glutamine was substituted with lysine.
    Matched MeSH terms: Hepatitis B virus/genetics*; Hepatitis B virus/immunology
  2. 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
  3. Monjezi R, Tan SW, Tey BT, Sieo CC, Tan WS
    J Virol Methods, 2013 Jan;187(1):121-6.
    PMID: 23022731 DOI: 10.1016/j.jviromet.2012.09.017
    The core antigen (HBcAg) of hepatitis B virus (HBV) is one of the markers for the identification of the viral infection. The main purpose of this study was to develop a TaqMan real-time detection assay based on the concept of phage display mediated immuno-PCR (PD-IPCR) for the detection of HBcAg. PD-IPCR combines the advantages of immuno-PCR (IPCR) and phage display technology. IPCR integrates the versatility of enzyme-linked immunosorbent assay (ELISA) with the sensitivity and signal generation power of PCR. Whereas, phage display technology exploits the physical association between the displayed peptide and the encoding DNA within the same phage particle. In this study, a constrained peptide displayed on the surface of an M13 recombinant bacteriophage that interacts tightly with HBcAg was applied as a diagnostic reagent in IPCR. The phage displayed peptide and its encoding DNA can be used to replace monoclonal antibody (mAb) and chemically bound DNA, respectively. This method is able to detect as low as 10ng of HBcAg with 10(8)pfu/ml of the recombinant phage which is about 10,000 times more sensitive than the phage-ELISA. The PD-IPCR provides an alternative means for the detection of HBcAg in human serum samples.
    Matched MeSH terms: Hepatitis B virus/genetics*; Hepatitis B virus/immunology*
  4. 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
  5. Candotti D, Lin CK, Belkhiri D, Sakuldamrongpanich T, Biswas S, Lin S, et al.
    Gut, 2012 Dec;61(12):1744-53.
    PMID: 22267593 DOI: 10.1136/gutjnl-2011-301281
    To investigate the molecular basis of occult hepatitis B virus (HBV) infection (OBI) in Asian blood donors.
    Matched MeSH terms: Hepatitis B virus/genetics*; Hepatitis B virus/immunology; Hepatitis B virus/isolation & purification
  6. Wong Ch, Goh K
    Biomed Imaging Interv J, 2006 Jul;2(3):e7.
    PMID: 21614253 MyJurnal DOI: 10.2349/biij.2.3.e7
    Hepatitis B virus (HBV) is one of the most well recognised human carcinogens. Since its discovery about 40 years ago, HBV has been studied extensively. This article summarises the evidence derived from various studies including epidemiological, animal model, histopathology studies and molecular genetics studies leading to the establishment of HBV as the main aetiological agent for hepatocellular carcinoma (HCC). The reduction in the incidence of childhood HCC due to mass hepatitis B vaccination in Taiwan is a dramatic demonstration of the critical aetiological role of hepatitis B in HCC. Thus it is essential for interventionalists to understand the epidemiological and pathogenesis of HCC to ensure optimal patient care.
    Matched MeSH terms: Hepatitis B virus
  7. Ramli M, Zulkafli Z, Chambers GK, Zilan RSAR, Edinur HA
    Oman Med J, 2020 Nov;35(6):e189.
    PMID: 33110633 DOI: 10.5001/omj.2020.86
    Objectives: Blood bank centers routinely screen for hepatitis B virus (HBV), hepatitis C virus (HCV), and human immunodeficiency virus (HIV) to ensure the safety of blood supply and thus prevent the dissemination of these viruses via blood transfusion. We sought to evaluate the detection of transfusion-transmitted infection (TTI) markers using standard serological methods and nucleic acid testing (NAT) among blood donors in Hospital Universiti Sains Malaysia.

    Methods: Donated blood units were assessed for the presence or absence of HBV, HCV, and HIV using two screening method: serology and NAT. Reactive blood samples were then subjected to serological confirmatory and NAT discriminatory assays.

    Results: A total of 9669 donors were recruited from September 2017 to June 2018. Among these, 36 donors were reactive either for HBV, HCV, or HIV by serological testing and eight by NAT screening. However, only 10 (three for HBV and seven for HCV) donors tested positive using serological testing and five (two for HBV and three for HCV) by NAT discriminatory assays. Note that all five NAT positive donors detected in the NAT discriminatory assays were confirmed to be serologically reactive. Therefore, the prevalence of HBV, HCV, and HIV was 0.03%, 0.1%, and 0.0%, respectively, in our donor pool.

    Conclusions: Both serological and NAT screening and confirmatory assays should be used routinely to reduce the risk of infection transmission via the transfusion of blood and blood components.

    Matched MeSH terms: Hepatitis B virus
  8. Chuon C, Takahashi K, Matsuo J, Katayama K, Yamamoto C, Ko K, et al.
    Sci Rep, 2019 08 21;9(1):12186.
    PMID: 31434918 DOI: 10.1038/s41598-019-48304-z
    Approximately 75% of hepatocellular carcinomas (HCC) occur in Asia; core promoter mutations are associated with HCC in HBV genotype C, the dominant genotype in Cambodia. We analyzed these mutations in Cambodian residents and compared them with HBV full genomes registered in GenBank. We investigated the characteristics of 26 full-length HBV genomes among 35 residents positive for hepatitis B surface antigen in Siem Reap province, Cambodia. Genotype C1 was dominant (92.3%, 24/26), with one case of B2 and B4 each. Multiple mutations were confirmed in 24 Cambodian C1 isolates, especially double mutation at A1762T/G1764A in 18 isolates (75.0%), and combination mutation at C1653T and/or T1753V and A1762T/G1764A in 14 isolates (58.3%). In phylogenetic analysis, 16 of 24 isolates were located in the cluster with Laos, Thailand, and Malaysia. In 340 GenBank-registered C1 strains, 113 (33.2%) had combination mutation amongst which 16.5%, 34.2%, and 95.2% were found in ASC, chronic hepatitis, and liver cirrhosis (LC)/HCC respectively (P 
    Matched MeSH terms: Hepatitis B virus/classification; Hepatitis B virus/genetics*; Hepatitis B virus/isolation & purification
  9. Riazalhosseini B, Mohamed Z, Apalasamy YD, Shafie NS, Mohamed R
    Biomed Rep, 2018 Sep;9(3):213-220.
    PMID: 30271596 DOI: 10.3892/br.2018.1126
    Interleukin-6 (IL-6) is a cytokine with a critical role in regulating the immune response to infectious disease. Studies have indicated that polymorphisms in the IL-6 gene may be linked to hepatitis B virus (HBV) infection. The purpose of the present study was to examine the association among IL-6 SNPs and haplotypes with HBV infection risk in a Malaysian population. A total of 1,246 Malaysian subjects with and without chronic hepatitis B were recruited for this study. Three IL-6 polymorphisms (rs2069837, rs1800796 and rs2066992) were genotyped using a Sequenom MassARRAY® platform. The results suggested that GC and CC genotypes of rs1800796 as well as GT and TT genotypes of rs2066992 were associated with protection against HBV infection (P<0.001). Furthermore, haplotypes GG and CT exhibited a significant association with protection against HBV (P=0.003 and =0.005, respectively); and haplotypes GG and CT exhibited a significant association with clearance of HBV infection (P=0.035 and =0.037, respectively). The present study indicates that two IL-6 SNPs (rs1800796 and rs2066992) are associated with clearance of chronic HBV or protection against HBV infection at allelic, genotypic and haplotypic levels.
    Matched MeSH terms: Hepatitis B virus
  10. Riazalhosseini B, Mohamed Z, Apalasamy YD, Eng HS, Mohamed R
    Pharmacogenet Genomics, 2016 Feb;26(2):74-9.
    PMID: 26529280 DOI: 10.1097/FPC.0000000000000187
    MicroRNAs (miRNAs) are small noncoding RNAs that have been implicated in mechanisms underlying various types of cancers including hepatocellular carcinoma (HCC). Reports have indicated that single nucleotide polymorphisms in miRNA-196A2 and miRNA-146A genes may contribute to the risk of progression of hepatitis B virus (HBV) infection to cirrhosis and HCC. This study aimed to examine the effect of miRNA-196A2 and miRNA-146A polymorphisms on the progression of HBV infection to cirrhosis and/or HCC in HBV patients in the Malaysian population.
    Matched MeSH terms: Hepatitis B virus
  11. Cheong XK, Wong Z, Nor NM, Lee BR
    BMC Gastroenterol, 2020 Sep 18;20(1):305.
    PMID: 32948126 DOI: 10.1186/s12876-020-01452-3
    BACKGROUND: Hepatitis B infection is a significant worldwide health issue, predispose to the development of liver cirrhosis and hepatocellular carcinoma. Entecavir is a potent oral antiviral agent of high genetic barrier for the treatment of chronic hepatitis B infection. Cutaneous adverse reaction associated with entecavir has rarely been reported in literature. As our knowledge, this case was the first case reported on entecavir induced lichenoid drug eruption.

    CASE PRESENTATION: 55 year old gentlemen presented with generalised pruritic erythematous rash on trunk and extremities. Six weeks prior to his consultation, antiviral agent entecavir was commenced for his chronic hepatitis B infection. Skin biopsy revealed acanthosis and focal lymphocytes with moderate perivascular lymphocyte infiltration. Skin condition recovered completely after caesation of offending drug and short course of oral corticosteroids.

    CONCLUSION: This case highlight the awareness of clinicians on the spectrum of cutaneous drug reaction related to entecavir therapy.

    Matched MeSH terms: Hepatitis B virus
  12. Cheek, Ken Lim, So, Har Ton
    Medicine & Health, 2007;2(1):1-25.
    MyJurnal
    Infection by hepatitis B virus (HBV) is a major global health-care problem. HBV is an accepted factor in the elevated risks for liver disease such as cirrhosis and development of hepatocellular carcinoma. This problem is particularly prevalent in the Asia-Pacific region which includes Malaysia. During infection, the hepatitis B e antigen (HBeAg) is produced in the hosts. This antigen is an important serological marker for diagnosing chronic hepatitis B. Seroconversion to anti-body (anti-HBe) corresponds to the improvement of disease prognosis. However, certain mutations such as the core promoter dual mutations (A1762G1764→T1762A1764), the codon 15 variants (C1858/ T1858) and the precore stop codon mutations (TGG→TAG) can affect the HBeAg expression. This has diagnostic and clinical implications. Besides that, the HBV can be grouped into eight genotypes (A to H). Moreover, genotypic subtypes and recombinants have been observed as well. Studies have observed that these can differ in their affiliations with the mutations above as well as with disease prognosis.
    Matched MeSH terms: Hepatitis B virus
  13. Sow, Emmy, Noorsuzana Mohd Shariff, Chong, Soon Eu, Tun Maizura Mohd. Fathullah, Siti Salmah Noordin
    MyJurnal
    Hepatitis B virus (HBV) infection is one of the major public health problems in Malaysia. It remains the most common permanent deferral among blood donors. In Malaysia, the national vaccination programme has been introduced since 1989 to prevent HBV transmission. The objective of this study is to determine the prevalence and associated risk factors of HBV infection among first-time blood donors after the implementation of the national hepatitis B vaccination programme. Methods: This is a retrospective cohort study involving tracing of the database of National Blood Centre Malaysia. The record of first-time blood donors who had donated between 1st January 2010 and 31st December 2015 and were screened HBV positive was reviewed and analysed. Results: There were 376,737 first-time donors who had donated blood and 575 of them screened positive for HBV. The overall prevalence of seropositive for hepatitis B was 0.15%. The prevalence was higher at 0.23% among donors born before the year 1989 (pre-vaccination era) compared to 0.05% among donors born in and after the year 1989 (post-vaccination era). Perinatal transmission was found to have 15 times higher odds of developing HBV infection as compared to those who had the combination of risk factors among those born after the year 1989 (adjusted OR=14.95, 95% CI 1.80=124.01). Conclusion: The implementation of the national vaccination programme reduced the prevalence of hepatitis B among donors who received vaccination at birth compared to those who did not.
    Matched MeSH terms: Hepatitis B virus
  14. Jobayer M, Chowdhury SS, Shamsuzzaman SM, Islam MS
    Mymensingh Med J, 2016 07;25(3):530-5.
    PMID: 27612902
    Hepatitis and AIDS are major public health problem globally. The aim of this study was to determine the sero-prevalence of hepatitis B, C virus and HIV infection among Bangladeshi overseas job seekers. This cross sectional study was carried out in the Department of Microbiology of Dhaka Medical College, Dhaka, Bangladesh from February 2013 to August 2013. A total of 2254 adult (18-45 years) male job seekers to Malaysia attending for health check up were enrolled. HBsAg, Anti-HCV, Anti-HIV were detected from venous blood by ELISA method using commercial kits. From the positive people, further history and information were collected by predesigned questionnaire. Prevalence of HBV was 2.35%, HCV was 0.13% and none was found positive for HIV. Prevalence of hepatitis was higher in the age group of 21-30 year and infection was more prevalent in married group. No significant relationship was found between hepatitis infection and religion, localities, profession. Only a few cases had history of possible major known route of transmission of virus. But most of them had history of taking injection or sharing blades in barber shop and history of circumcision. About 96% population had no history of hepatitis B vaccination. None was co-infected with HBV and HCV. Prevalence of hepatitis B virus infection in adult population appears to be on decline and hepatitis C and HIV infection is still low in Bangladesh. In majority of the positive person, routes of transmission of viruses were not well established.
    Matched MeSH terms: Hepatitis B virus
  15. Yap WB, Tey BT, Alitheen NB, Tan WS
    J Biosci Bioeng, 2012 Jan;113(1):26-9.
    PMID: 22024533 DOI: 10.1016/j.jbiosc.2011.09.007
    The C-terminal domain of Nipah virus (NiV) nucleocapsid protein (NP₄₀₁₋₅₃₂) was inserted at the N-terminus and the immunodominant loop of hepatitis B core antigen (HBc). The stability of NP₄₀₁₋₅₃₂ increased tremendously when displayed on the HBc particles. These particles reacted specifically with the swine anti-NiV and the human anti-HBc antisera.
    Matched MeSH terms: Hepatitis B virus/metabolism*
  16. 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
  17. Lee MF, Chan ES, Tan WS, Tam KC, Tey BT
    J Chromatogr A, 2015 Oct 9;1415:161-5.
    PMID: 26358561 DOI: 10.1016/j.chroma.2015.08.056
    Poly(oligo(ethylene glycol) methacrylate) (POEGMA), an inert polymer was grafted onto an anion exchange adsorbent for the exclusion of relatively larger hepatitis B virus-like particles (HB-VLPs) from the anion exchange ligand (Q) and at the same time this process allowed the selective adsorption of smaller size Escherichia coli host cell proteins (HCPs). The chain lengths of the POEGMA grafted were modulated by varying the amount of monomers used in the polymer grafting. The purification factor and yield of the HB-VLPs obtained from the flow-through of negative chromatography were 2.3 and 66.0±3.1%, respectively, when shorter chain length of POEGMA (SQ) was grafted. Adsorbent grafted with longer chain of POEGMA (LQ) excluded some HCPs that are larger in size together with the HB-VLPs, reducing the purity of the recovered HB-VLPs. Further heat-treatment of the flow-through pool from SQ followed by centrifugation increased the purity of heat stable HB-VLPs to 87.5±1.1%. Heat-treatment of the flow through sample resulted in thermal denaturation and aggregation of HCPs, while the heat stable HB-VLPs still remained intact as observed under a transmission electron microscope. The performance of the negative chromatography together with heat treatment in the purification of HB-VLPs is far better than the reported bind-and-elute techniques.
    Matched MeSH terms: Hepatitis B virus/metabolism*
  18. Muhamad A, Ho KL, Rahman MB, Tejo BA, Uhrín D, Tan WS
    Org Biomol Chem, 2015 Jul 28;13(28):7780-9.
    PMID: 26100394 DOI: 10.1039/c5ob00449g
    Hepatitis B virus (HBV) infection remains a health problem globally despite the availability of effective vaccines. In the assembly of the infectious virion, both the preS and S regions of the HBV large surface antigen (L-HBsAg) interact synergistically with the viral core antigen (HBcAg). Peptides preS and S based on the L-HBsAg were demonstrated as potential inhibitors to block the viral assembly. Therefore, the objectives of this study were to determine the solution structures of these peptides and study their interactions with HBcAg. The solution structures of these peptides were solved using (1)H, (13)C, and (15)N NMR spectroscopy. Peptide preS has several structured regions of β-turns at Ser7-Pro8-Pro9, Arg11-Thr12-Thr13 and Ser22-Thr23-Thr24 sequences whereas peptide S has only one structured region observed at Ser3-Asn4-His5. Both peptides contain bend-like structures surrounding the turn structures. Docking studies revealed that both peptides interacted with the immunodominant region of HBcAg located at the tip of the viral capsid spikes. Saturation Transfer Difference (STD) NMR experiments identified several aromatic residues in peptides preS and S that interact with HBcAg. This study provides insights into the contact regions of L-HBsAg and HBcAg at atomic resolution which can be used to design antiviral agents that inhibit HBV morphogenesis.
    Matched MeSH terms: Hepatitis B virus/drug effects
  19. 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
  20. Goh CL, Kamarudin A, Chan SH, Rajan VS
    Genitourin Med, 1985 Apr;61(2):127-9.
    PMID: 3980022
    The prevalence of hepatitis B virus markers in 121 men and 239 women prostitutes was studied. Of 33 (9.7%) with hepatitis B surface antigen (HBsAg), nine (27.3%) also had hepatitis Be antigen, which was more prevalent in men than women. Antibodies to HBsAg (anti-HBs) and to hepatitis B core antigen (anti-HBc) were found in about 71% of men and women prostitutes. Hepatitis B virus markers were more prevalent in men than in women prostitutes. Compared with other people, prostitutes had a significantly greater prevalence of hepatitis B virus markers. This study strongly suggested the importance of sexual transmission of infection with hepatitis B virus in a country where infection is endemic.
    Matched MeSH terms: Hepatitis B virus/immunology*
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