• Clinical and Experimental Pediatrics
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• v.50 no.4
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• pp.348-354
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• 2007

Purpose : Perinatal hepatitis B viral infection is decreasing; however, 10% of babies to HBeAg positive mothers still become chronic carriers despite perinatal prophylaxis. Although, the cause of prophylaxis failure is still unclear, an importance of maternal HBV-DNA level at the delivery time has been suggested. This study was established to certify if it would be a useful predictable factor for the outcome of perinatal prophylaxis. Methods : Twenty-nine HBeAg positive mothers whose babies had known outcomes of prophylaxis were selected. To determine the amount of maternal HBV-DNA, a quantitative PCR was performed with the WHO International Standard for HBV DNA NAT assays. Results : The mean logarithm HBV-DNA level of mothers with failed outcomes was significantly higher than that of mothers with succeessful outcomes (7.99 vs. 6.72, P=0.015). The predictable maternal HBV-DNA cut-off level to prophylaxis outcome was $2.83{\times}10^7copies/mL$ (100 pg/mL). None out of the case 16 (0%) who had below this level, and 5 out of 13 (38.5%) who had above this level of maternal HBV-DNA failed in perinatal prophylaxis. Conclusion : Mothers with higher levels of HBV-DNA at delivery time would be prone to a worse outcome of prophylaxis using the conventional approach. Perinatal prophylaxis failure rate can be reduced, if we try to introduce more potent prophylactic treatment into the cases with this risk factor.

• The Korean Journal of Nuclear Medicine Technology
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• v.23 no.1
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• pp.35-39
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• 2019

Purpose Hepatitis B virus (hepatitis B virus, HBV) infection is a worldwide major public health problem and it is known as a major cause of chronic hepatitis, liver cirrhosis and liver cancer. And serologic tests of hepatitis B virus is essential for diagnosing and treating these diseases. In addition, with the development of molecular diagnostics, the detection of HBV DNA in serum diagnoses HBV infection and is recognized as an important indicator for the antiviral agent treatment response assessment. We performed HBeAg assay using Immunoradiometric assay (IRMA) and Chemiluminescent Microparticle Immunoassay (CMIA) in hepatitis B patients treated with antiviral agents. The detection rate of HBV DNA in serum was measured and compared by RT-PCR (Real Time - Polymerase Chain Reaction) method Materials and Methods HBeAg serum examination and HBV DNA quantification test were conducted on 270 hepatitis B patients undergoing anti-virus treatment after diagnosis of hepatitis B virus infection. Two serologic tests (IRMA, CMIA) with different detection principles were applied for the HBeAg serum test. Serum HBV DNA was quantitatively measured by real-time polymerase chain reaction (RT-PCR) using the Abbott m2000 System. Results The detection rate of HBeAg was 24.1% (65/270) for IRMA and 82.2% (222/270) for CMIA. Detection rate of serum HBV DNA by real-time RT-PCR is 29.3% (79/270). The measured amount of serum HBV DNA concentration is $4.8{\times}10^7{\pm}1.9{\times}10^8IU/mL$($mean{\pm}SD$). The minimum value is 16IU/mL, the maximum value is $1.0{\times}10^9IU/mL$, and the reference value for quantitative detection limit is 15IU/mL. The detection rates and concentrations of HBV DNA by group according to the results of HBeAg serological (IRMA, CMIA)tests were as follows. 1) Group I (IRMA negative, CMIA positive, N = 169), HBV DNA detection rate of 17.7% (30/169), $6.8{\times}10^5{\pm}1.9{\times}10^6IU/mL$ 2) Group II (IRMA positive, CMIA positive, N = 53), HBV DNA detection rate 62.3% (33/53), $1.1{\times}10^8{\pm}2.8{\times}10^8IU/mL$ 3) Group III (IRMA negative, CMIA negative, N = 36), HBV DNA detection rate 36.1% (13/36), $3.0{\times}10^5{\pm}1.1{\times}10^6IU/mL$ 4) Group IV(IRMA positive, CMIA negative, N = 12), HBV DNA detection rate 25% (3/12), $1.3{\times}10^3{\pm}1.1{\times}10^3IU/mL$ Conclusion HBeAg detection rate according to the serological test showed a large difference. This difference is considered for a number of reasons such as characteristics of the Ab used for assay kit and epitope, HBV of genotype. Detection rate and the concentration of the group-specific HBV DNA classified serologic results confirmed the high detection rate and the concentration in Group II (IRMA-positive, CMIA positive, N = 53).

• Molecules and Cells
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• v.42 no.1
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• pp.67-78
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• 2019

Methylation of HBV cccDNA has been detected in vivo and in vitro; however, the mechanism and its effects on HBV replication remain unclear. HBx derived from a 1.2-mer HBV replicon upregulated protein levels and enzyme activities of DNA methyltransferase 1 (DNMT1), 3a, and 3b, resulting in methylation of the negative regulatory region (NRE) in cccDNA, while none of these effects were observed with an HBx-null mutant. The HBx-positive HBV cccDNA expressed higher levels of HBc and produced about 4-fold higher levels of HBV particles than those from the HBx-null counterpart. For these effects, HBx interrupted the action of NRE binding protein via methylation of the C-1619 within NRE, resulting in activation of the core promoter. Treatment with 5-Aza-2′dC or DNMT1 knock-down drastically impaired the ability of HBx to activate the core promoter and stimulate HBV replication in 1.2-mer HBV replicon and in vitro infection systems, indicating the positive role of HBx-mediated cccDNA methylation in HBV replication.

• Journal of Applied Biological Chemistry
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• v.49 no.4
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• pp.143-147
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• 2006

A rapid PCR-based assay for detecting hepatitis B viral DNA(HBV DNA) in serum and plasma was developed using a new PCR instrument named GenSpector(TMC-1000, Samsung electronics). PCR was carried out using a chip-based platform, which enabled 50 PCR cycles with internal controls, and melting-curve analysis in 30 minutes. Verification of the amplified HBV DNA product and the internal control was based on specific melting temperatures(Tm) analysis, executed by the GenSpector software. Primers were designed within the region conserved through HBV genotypes A to F. The lower limit of detection was 840 copies/ml serum, conducted with serial dilutions of a HBV DNA positive control(ACCURUN 325 series 700, Boston Biomedica Inc.). The assay was also compared to another assay for HBV DNA(Versant HBV DNA 3.0 assay, Bayer HealthCare) for 200 samples(each 100 clinical negative and positive samples). The sensitivity and specificity were 100% matched. This rapid PCR-based assay is specific, reproducible, and enables qualitative detection of HBV DNA.

• Journal of Yeungnam Medical Science
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• v.14 no.1
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• pp.155-167
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• 1997

The identification of serum HBV DNA is very important for the assessment of the disease activity in persistent infection, for the evaluation of the infectivity of an individuals blood. The dot blot, however, has limited sensitivity and sometimes inconsistent with other serological markers and clinical settings. Using the most important recent advance in molecular biology, the polymerase chain reaction(PCR), specific DNA sequences can be amplified more than a million-fold in a few hours and with this technique the detection of the extreme low level of DNA is possible. This study was to determine sensitivity of the PCR for the detection of serum HBV DNA in comparison with dot blot analysis and to investigate the serum HBV DNA status and clinical significance of PCR in patients with chronic HBsAg positive liver disease. The subjects of this study were 17 patients with asymptomatic HBsAg carriers(9 HBeAg positive patients, 8 anti-HBe positive patients), 91 chronic hepatitis B(50 HBeAg positive patients, 41 anti-HBe positive patients), 57 liver cirrhosis(21 HBeAg positive patients, 36 anti-HBe positive patients), 27 hepatocellular carcinoma(10 HBeAg positive patients, 17 anti-HBe positive patients). The results were summerized as following; The detection rates of HBV DNA by dot blot, PCR were 58.9%, 72.2% in HBeAg positive patients, 34.3%, 53.9% in anti-HBe positive patients. The detection rates of HBV DNA by PCR in HBeAg negative patients were 25.0% in asymptomatic HBsAg carriers, 61.0% in chronic hepatitis B, 52.8% in liver cirrhosis, 52.9% in hepatocellular carcinoma. The positive rate for HBV DNA is a significant difference between HBeAg positive and negative asymptomatic HBsAg carriers, but not significantly difference in other groups. In conclusions, this study confirmed that the PCR is much more sensitive than the dot blot analysis in detecting the HBV DNA in the sera of patients with chronic liver disease. The presence of HBV DNA in the serum was detected by PCR with higher sensitivity and it suggested that active viral replication is still going on in most patients with chronic HBsAg positive liver disease irrespective of HBeAg/anti-HBe status, and PCR may be used as a prognostic factor in asymptomatic HBsAg carriers.

• Biomedical Science Letters
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• v.18 no.3
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• pp.283-290
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• 2012

In this study, we investigated the virological characteristics, HBV DNA levels and presence of mutations of "a" determinant in the HBsAg S gene in chronic hepatitis B patients with coexisting HBsAg and anti-HBs. The 18 patients who were diagnosed with chronic hepatitis B were both positive for HBsAg and anti-HBs. HBV Among them, 15 patients were DNA positive. The median of HBV DNA levels in serum was $2.18{\times}10^7$ copies/mL with the HBsAg+/anti-HBsAb+ patients. Also, 4 of 8 HBeAg negative patients had HBV DNA levels higher than $10^4$ copies/mL and the median of HBV DNA levels was $2.03{\times}10^6$ copies/mL, which were significantly high. These results showed that viral replication still existed in most of the patients of the concomitant HBsAg and anti-HBs, and even in the some HBeAg negative patients. Furthermore, mutation within the "a" determinant of HBV were found in 7 of 15 patients. The most frequent changes were located at positions aa126. In addition, one mutation observed for HBsAg only positive.

• Archives of Pharmacal Research
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• v.19 no.6
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• pp.469-474
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• 1996

A rapid and sensitive method has been developed to detect hepatitis B virus DNA (HBV) by nested polymerase chain reaction (PCR) technique with primers specific for the surface and core regions in capillary thermal cycler within 80 min. The lower limit for detection by present PCR method is $10^{-5}$ pg of recombinant HBV DNA which is equivalent to that determined by one round of PCR amplification and Southern blot hybridization analysis. When boiled HBV positive serum was serially diluted 10-fold, HBV DNA was successfully determined in $1{\mu}l-10^{-3}$ of serum. HBV DNA was detected by present method in 69 clinical samples including HBsAg positives and negatives by enzyme-linked immunosorbent assay (ELISA). When serum samples were amplified by nested PCR using surface and core region primers, HBV DNAs were detected in 37 of 69 samples (53.6%) and 18 of 69 samples (26.1%), respectively. These results can inform the infectious state of HBsAg positive pateints. A simple and rapid nested PCR protocol by using boiled serum as DNA template has been described for the clinical utility to determine HBV DNA in human serum.

• Proceedings of the Korean Society of Applied Pharmacology
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• 1996.04a
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• pp.178-178
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• 1996

Hepatitis B virus (HBV) infection is one of the serious problems in Southeast Asia including Korea because it causes chronic hepatitis, which can easily be transformed In fatal conditions such as cirrhosis and hepatoma. Even though lots of informations on structural characteristics and gene expression mechanisms have been accumulated, the mechanism for HBV-induced hepatocellular injury which is believed to be the consequences of the immunological response is not well understood. In order tn perform immunopathological studies for prevention and treatment of HBV infection, we designed transgenic mice as a disease model which can mimic HBV infection, In this study, a promoter-HBV DNA fragment for the preparation of HBV transgenic mice has been constructed. To add a proper enzyme site on 5' end of HBV gene, total HBV (subtype adr) gene was inserted into BamHI site of pBluescript SK vector and reextracted by PstI-SacI treatment A liver-specific promoter, rat ${\alpha}$ 2u globulin gene promoter, was insrted to pBluescript SK vector and reextracted by BamHI-PstI treatment, Promoter-HBV DNA was constructed by ligation of two fragments using identical PstI sites. For large scale production of promoter-HBV DNA, it was inserted to BamHI-SacI site of pBluescript SK vector.

• Journal of Yeungnam Medical Science
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• v.12 no.2
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• pp.339-346
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• 1995

Assays for HBsAg, HBV DNA, anti-HBc and anti-HBs of 285 units of packed red blood cells supplied by Taegu Red Cross Blood Center were performed to evaluate the correlation between the prevalence of HBV DNA and the serologic markers for hepatitis B virus. None of 285 plasma samples was positive for HBsAg, however, HBV DNA were detected by polymerase chain reaction in 2 samples which both presented only with anti-HBc positivity. Of 204 samples tested for anti-HBs, 96 samples(47.1%) were positive and among 216 samples tested for anti-HBc, 80 samples(37.0%) were positive. Of 193 samples tested for both anti-HBs and anti-HBc, 80(41.1%) were all negative and 48(24.9%) were positive on both tests. Those samples which showed positivity only to anti-HBc were 25(13.0%). Considering the above results, transfusion-transmitted hepatitis B virus infection could be prevented by discarding anti-HBc positive blood, however, that may bring insufficient supply of donor bloods in the country like Korea where the prevalence of anti-HBc is high. Anti-HBc positive blood unequivocally positive for anti-HBs should be considered noninfectious for HBV and should be allowed to be transfused. It would reduce the amount of discarding donor blood as the routine blood donor screening tests presently used at Korea Red Cross Blood Center supplemented by anti-HBs and anti-HBc testing.

• BMB Reports
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• v.31 no.5
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• pp.498-502
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• 1998

HBV polymerase shares several regions of amino acid homology with other DNA-directed and RNA-directed polymerases. The amino acid residues $Asp^{429}$, $Gly^{518}$, $Asp^{551}$, $Lys^{585}$, and $Gly^{641}$ in the conserved motifs A, B', C, D, and E in the polymerase domain of HBV polymerase were mutated to alanine or histidine by in vitro site-directed mutagenesis. Those mutants were overexpressed, purified, and analyzed against DNA-dependent DNA polymerase activity and affinity for DNA binding. All those mutants did not show DNA-dependent DNA polymerase activities indicating that those five amino acid residues are all critical in DNA polymerase activity. South-Western analysis shows that amino acid residues $ASp^{429}$ and $ASp^{551}$ are essential to DNA binding, and $Gly^{318}$ and $Gly^{585}$ also affect DNA binding to a certain extent.