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Trends in hepatitis B virus infection among blood donors in Kelantan, Malaysia: a retrospective study

Yousuf R, Rapiaah M, Ahmed SA, Rosline H, Salam A, Selamah S, et al.

Southeast Asian J Trop Med Public Health, 2007 Nov;38(6):1070-4.
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 Surface Antigens/isolation & purification
A phage-displayed cyclic peptide that interacts tightly with the immunodominant region of hepatitis B surface antigen

Tan WS, Tan GH, Yusoff K, Seow HF

J Clin Virol, 2005 Sep;34(1):35-41.
PMID: 16087122

The surface antigen (HBsAg) of hepatitis B virus (HBV) is highly conformational and generally evokes protective humoral immune response in human. A disulfide constrained random heptapeptide library displayed on the coat protein III of filamentous bacteriophage M13 was employed to select specific ligands that interact with HBsAg subtype ad. Fusion phages carrying the amino acid sequence ETGAKPH and other related sequences were isolated. The binding site of peptide ETGAKPH was located on the immunodominant region of HBsAg. An equilibrium binding assay in solution showed that the phage binds tightly to HBsAg with a relative dissociation constant (KDrel) of 2.9+/-0.9 nM. The phage bearing this peptide has the potential to be used as a diagnostic reagent and two assays for detecting HBsAg in blood samples are described.

Matched MeSH terms: Hepatitis B Surface Antigens/isolation & purification
Fulltext Enhanced cell disruption strategy in the release of recombinant hepatitis B surface antigen from Pichia pastoris using response surface methodology

Tam YJ, Allaudin ZN, Lila MA, Bahaman AR, Tan JS, Rezaei MA

BMC Biotechnol, 2012 Oct 05;12:70.
PMID: 23039947 DOI: 10.1186/1472-6750-12-70

BACKGROUND: Cell disruption strategies by high pressure homogenizer for the release of recombinant Hepatitis B surface antigen (HBsAg) from Pichia pastoris expression cells were optimized using response surface methodology (RSM) based on the central composite design (CCD). The factors studied include number of passes, biomass concentration and pulse pressure. Polynomial models were used to correlate the above mentioned factors to project the cell disruption capability and specific protein release of HBsAg from P. pastoris cells.
RESULTS: The proposed cell disruption strategy consisted of a number of passes set at 20 times, biomass concentration of 7.70 g/L of dry cell weight (DCW) and pulse pressure at 1,029 bar. The optimized cell disruption strategy was shown to increase cell disruption efficiency by 2-fold and 4-fold for specific protein release of HBsAg when compared to glass bead method yielding 75.68% cell disruption rate (CDR) and HBsAg concentration of 29.20 mg/L respectively.
CONCLUSIONS: The model equation generated from RSM on cell disruption of P. pastoris was found adequate to determine the significant factors and its interactions among the process variables and the optimum conditions in releasing HBsAg when validated against a glass bead cell disruption method. The findings from the study can open up a promising strategy for better recovery of HBsAg recombinant protein during downstream processing.

Matched MeSH terms: Hepatitis B Surface Antigens/isolation & purification
Hepatitis B surveillance in Singapore

Goh KT

Ann Acad Med Singap, 1980 Apr;9(2):136-41.
PMID: 6775577

257 cases of acute hepatitis B were reported between January 1977 and June 1979. This constituted about one-third of all reported acute viral hepatitis cases in Singapore. The mean annual morbidity and mortality rates per 100,000 was 4.4 and 0.12 respectively. The case-fatality rate was 2.7%. The age-specific morbidity rates were high in the 15-24 and 25-34 years age groups, while the ethnic specific morbidity rate was highest in Indians. The male to female ratio was 4.6: 1. Cases were concentrated in urban and suburban areas with high population density. Three outbreaks, one traced to contaminated needles and syringes, one to contaminated tattoo neeedles, and amongst close contacts, were described. Although parenteral procedures were associated with hepatitis B infection (p < 0.005), non-parenteral or inapparent parenteral mode of transmission probably contributes to a significant extent in the transmission of hepatitis B in Singapore. Studies to determine the role of perinatal transmission, and of vectors, in maintaining the endemicity of the disease, were suggested.

Matched MeSH terms: Hepatitis B Surface Antigens/isolation & purification
An Overview of Hepatitis B Virus Surface Antigen Mutant in the Asia Pacific

Hudu SA, Malik YA, Niazlin MT, Harmal NS, Sekawi Z

Curr Issues Mol Biol, 2014;16:69-78.
PMID: 24014801

Hepatitis B virus infection is a serious health problem worldwide, and more than 350 million people are chronic carriers, constituting a major global threat. Southeast Asia and the Western Pacific have the highest levels of endemicity in the world, with an estimated seroprevalence ranging between 2% and 31%. Mutations in the hepatitis B surface antigen (HBsAg) have been reported in many parts of the world but are most common in Asian infants; such mutants have several clinical effects, such as the development of hepatocellular carcinoma. Diagnostic failures by commercial assays have reduced the diagnostic effectiveness of HBsAg detection. For example the substitution of an amino acid in the major hydrophilic region of the S gene reduces the binding of hepatitis B surface antibodies leading to immune escape. The safety of blood transfusion may be compromised by current screening tests due to escape from being neutralised by antibodies induced by HBsAg mutants, and undetectable levels of viral surface protein. Data on the epidemiology of HBsAg mutation in Asia Pacific are scant; however, this manuscript has reviewed the available information on the epidemiology of HBsAg mutation in Asia Pacific.

Matched MeSH terms: Hepatitis B Surface Antigens/isolation & purification