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/complications; Hepatitis B/epidemiology; Hepatitis B/pathology; Hepatitis B/virology*; Hepatitis B Surface Antigens/blood; Hepatitis B virus/classification; Hepatitis B virus/genetics*; Hepatitis B virus/isolation & purification
Hepatitis B surface antigen can be serologically defined as ayw1, ayw2, ayw3, ayw4, ayr, adw2, adw4 and adrq+ or adrq-. A study of common HBsAg subtypes in 44 HBsAg reactive sera in University Hospital was conducted using a solid-phase sandwich EIA. Eleven samples were found not typable and among the 33 typable HBsAg reactive sera, 3 HBsAg subtypes: adw, adr and ayw were identified. Subtype adw was found in 66.7% (22/33) of the typable HBsAg reactive sera; 24.2% (8/33) was of subtype adr and 6.0% (2/33) of subtype ayw. One sample was found to be reactive to both adw and adr. HBsAg subtype adw was found more commonly in Chinese but among the Malays, HBsAg subtype adr appeared to predominate. However, the small sample size precludes firm conclusions on the predominant subtype among the Malays.
Matched MeSH terms: Hepatitis B Antibodies/analysis*; Hepatitis B Surface Antigens/analysis*
Hepatitis B virus (HBV) DNA in the serum of 31 patients with histologically confirmed primary hepatocellular carcinoma (PHC) from Malaysia and Indonesia was quantitated by densitometric scanning of autoradiograms obtained by Southern blot DNA hybridization, after electrophoresis using a 32P DNA cloned into plasmid pBR325 as a probe. This quantitation after electrophoresis is more informative than the usual spot hybridization technique. Five of the 31 sera were positive for HBV DNA. Levels ranged between 1.36 pq and 143.18 pq per ml of serum, and the levels of HBsAg, anti-HBs, anti-HBc, HBeAg and anti-HBe in the serum were serologically determined. All five sera positive for HBV DNA were also positive for HBsAg. Three of the five positive for HBV DNA were positive for HBeAg and negative for anti-HBe. Two of the sera positive for HBV DNA were negative for HBeAg but positive for anti-HBe. All sera negative for HBV DNA were also negative for HBeAg. Many sera which were negative for HBV DNA and HBeAg were positive for HBsAg. Of the 31 sera from PHC patients, 23 had at least one HBV marker positive (74.2%).
Matched MeSH terms: Hepatitis B Antigens/analysis; Hepatitis B virus/genetics*
In the 7-year period between 1980 and 1987, six cases of childhood primary hepatocellular carcinoma (PHC) were confirmed histologically in our institution. Hepatitis B surface antigen (HBsAg) seropositivity was confirmed in five of the cases, and tissue HBsAg was shown in four of these using the Shikata's orcein stain. An associated maternal HBsAg seropositivity was shown in two of the seropositive children. The youngest seropositive patient who developed PHC was 7 years old. The mother of this patient was also seropositive. These observations support a causal relation between childhood Hepatitis B virus infection and PHC. The importance of vertical or perinatal transmission of HBV in the causation of childhood PHC and the prophylactic role of childhood vaccination is emphasized. Attention is also drawn to the relative short malignant transformation time seen in some of these patients.
Matched MeSH terms: Hepatitis B/complications*; Hepatitis B Surface Antigens/analysis
The Asia-Pacific Expert Committee on Hepatitis B Management recently reviewed the impact of hepatitis B in the region and assessed the differences and similarities observed in the practical management of the disease in individual Asia-Pacific countries. Hepatitis B is a major health concern in the Asia-Pacific region, and of all chronically infected carriers worldwide, approximately 75% are found in Asia. The disease poses a considerable burden on healthcare systems, and is likely to remain a cause of substantial morbidity and mortality for several decades. Disease prevention activities, including screening and vaccination programs, have been implemented successfully in some Asia-Pacific countries and similar measures are being established in other parts of the region. The management of hepatitis B in the Asia-Pacific varies throughout the region, with each country confronting different issues related to treatment options, disease monitoring and duration of therapy. The influence of cost, availability of diagnostic equipment, and patient awareness and compliance are of additional concern. Although guidelines such as those developed by the Asian Pacific Association for the Study of the Liver have been created to address problems encountered in the management of hepatitis B, many physicians in the region still find it difficult to make satisfactory management decisions because of the treatment choices available. This article examines the different approaches to hepatitis B management in a number of Asia-Pacific countries, and highlights the difficulties that can arise when adhering to treatment guidelines and disease prevention solutions that have proved to be successful in the region.
The MLF since its inception in 1996 has endeavored to develop a coordinated approach towards the improved care and treatment of liver diseases in Malaysia. Its close liaison with the Malaysian MOH, local medical associations, and corporate bodies has contributed to the success of its many programs. Educating the public, research, and training have been important elements of successful hepatitis disease control programs. Hepatitis Days have been proven to be very successful in raising the awareness of the general public to hepatitis disease. Rapid screening and vaccination has also helped to remove the social stigma associated with the disease, eliminated the need for numerous clinic appointments, and rendered vaccination more accessible to the public. The MLF perspective emphasizes the need for collaborative effort between Government bodies and other agencies, such as non-governmental organizations, laboratories, and the medical fraternity, to ensure the overall success of hepatitis disease management programs.
One hundred and ninety hepatitis B surface antigen positive (HBsAG+) sera were subtyped, belonging to : blood donors, hepatitis patients, patients and staff in a hemodialysis unit, all from Kuala Lumpur; Malaysian aborigines from three jungle locations in Peninsular Malaysia; and East Malaysians from Sarawak, East Malaysia; Three subtypes adr, adw and ayw were present in Malaysia in the following frequencies: 44%, 29%, and 27%, respectively; In Kuala Lumpur 87% had subdeterminant d and 13 per cent y, whereas in the deep jungle aborigines of Perak and Pahang, the y subdeterminant was present in 87% and the d in 13%. A similar pattern of preponderance of y prevailed in Sarawak, East Malaysia. In Kuala Lumpur the two main ethnic groups, Malays and Chinese, differed in subtype distribution, in that adr predominated in the Malays (61%), while the adw predominated in the Chinese (51%); Subtype distribution was not related to age or sex of carriers of the antigen, or to whether they had hepatitis, or asymptomatic antigenemia.
Matched MeSH terms: Hepatitis B/immunology; Hepatitis B Antigens*
Virus-like nanoparticles (VLNPs) have been studied extensively as nanocarriers for targeted drug delivery to cancer cells. However, VLNPs have intrinsic drawbacks, in particular, potential antigenicity and immunogenicity, which hamper their clinical applications. Thus, they can be eliminated easily and rapidly by host immune systems, rendering these nanoparticles ineffective for drug delivery. The aim of this study was to reduce the antigenicity of hepatitis B core antigen (HBcAg) VLNPs by shielding them with a hydrophilic polymer, poly(2-ethyl-2-oxazoline) (PEtOx). In the present study, an amine-functionalized PEtOx (PEtOx-NH2) was synthesized using the living cationic ring-opening polymerization (CROP) technique and covalently conjugated to HBcAg VLNPs via carboxyl groups. The PEtOx-conjugated HBcAg (PEtOx-HBcAg) VLNPs were characterized with dynamic light scattering and UV-visible spectroscopy. The colloidal stability study indicated that both HBcAg and PEtOx-HBcAg VLNPs maintained their particle size in Tris-buffered saline (TBS) at human body temperature (37 °C) for at least five days. Enzyme-linked immunosorbent assays (ELISA) demonstrated that the antigenicity of PEtOx-HBcAg VLNPs reduced significantly as compared with unconjugated HBcAg VLNPs. This novel conjugation approach provides a general platform for resolving the antigenicity of VLNPs, enabling them to be developed into a variety of nanovehicles for targeted drug delivery.
Matched MeSH terms: Hepatitis B Core Antigens/chemistry; Hepatitis B virus*
A total of 941 screening tests for HBV antigen and antibody were done. These included 342 male adults, 492 female adults and 107 children under 15 years. Most of them had no clinical symptoms. There were 18 cases of active hepatitis of various causes. Percentage of positive for HBsAg: adult male 12.3%, adult female 6.5%, children under 15 years 1.9%, overall 8.1%. Percentage of positive for anti-HBs antibody: 18.5%.
Study site: private laboratory, Kuching, Sarawak, Malaysia
The infectiousness with regard to HBV Infection of staff and patients in various units of the General Hospital, Kuala Lumpur
was assessed. It was found that all units, with the exception of the obstetric unit, were equally high risk areas. At least 50% of the patients in all these units had one or more of the markers. Among the medical staff, the anaesthetists had the highest
incidence of HBV markers (100%) while medical officers who had worked for three years or more were more likely to have to
have the HBV markers. The degree of infectiousness of the nurses In HDU and ICU/OT was found to be similar.
Matched MeSH terms: Hepatitis B/immunology*; Hepatitis B Antigens/analysis*
Hepatitis B virus (HBV) has been divided into 10 genotypes, A to J, based on an 8% nucleotide sequence divergence between genotypes. The conventional practice of using a single set of primers to amplify a near-complete HBV genome is hampered by its low analytical sensitivity. The current practice of using overlapping conserved primer sets to amplify a complete HBV genome in a clinical sample is limited by the lack of pan-primers to detect all HBV genotypes. In this study, we designed six highly conserved, overlapping primer sets to cover the complete HBV genome. We based our design on the sequences of 5,154 HBV genomes of genotypes A to I downloaded from the GenBank nucleotide database. These primer sets were tested on 126 plasma samples from Malaysia, containing genotypes A to D and with viral loads ranging from 20 to >79,780,000 IU/ml. The overall success rates for PCR amplification and sequencing were >96% and >94%, respectively. Similarly, there was 100% amplification and sequencing success when the primer sets were tested on an HBV reference panel of genotypes A to G. Thus, we have established primer sets that gave a high analytical sensitivity for PCR-based detection of HBV and a high rate of sequencing success for HBV genomes in most of the viral genotypes, if not all, without prior known sequence data for the particular genotype/genome.
Matched MeSH terms: Hepatitis B/virology; Hepatitis B virus/genetics*
A retrospective study was carried out to determine the frequency of the pre-core stop codon mutant virus in a group of chronic hepatitis B carriers: 81 cases were considered [33 hepatits B e antigen (HBe) positive and 48 HBe negative]. All of the HBe positive cases had detectable viral DNA by hybridization analysis; in the case of the HBe negative cases, one third had detectable viral DNA by hybridization analysis and two thirds had HBV DNA detectable by polymerase chain reaction (PCR) amplification. Pre-core stop codon mutant detection was carried out on all specimens using allele-specific oligonucleotide hybridization following PCR amplification of the target sequence. The pre-core mutant was detected in 13/33 (39.4%) of HBe positive cases and in 32/48 (66.7%) of HBe negative cases. Sequence analysis was carried out on 8 of the 16 HBe negative specimens that did not carry the pre-core mutant virus to determine the molecular basis for the HBe minus phenotype in these cases: the 1762/1764 TA paired mutation in the second AT rich region of the core promoter was detected in five cases; a start codon mutation was detected in one case. The predominant mutation resulting in the HBe minus phenotype in our isolates was the 1896A pre-core ("pre-core stop codon") mutation; other mutations responsible for the phenotype included the core promoter paired mutation and pre-core start codon mutation. In view of the high frequency of the pre-core mutant virus, sequence analysis was performed to determine the virus genotype on the basis of the nucleotide sequence of codon 15. The sequences of 21 wild type virus (14 HBe positive and 7 HBe negative cases) were examined: 15 were found to be codon 15 CCT variants (71.4%); the frequency in the HBe positive group was 12/14 (85.7%), while that in the HBe negative group was 3/7 (42.9%). The high frequency of the codon 15 CCT variant in association with the frequent occurrence of the pre-core mutant in our isolates concurs with the results of other studies.
Matched MeSH terms: Hepatitis B Core Antigens/genetics*; Hepatitis B, Chronic/genetics*
Hepatitis B core antigen (HBcAg) expressed in Escherichia coli is able to self-assemble into large and small capsids comprising 240 (triangulation number T = 4) and 180 (triangulation number T = 3) subunits, respectively. Conventionally, sucrose density gradient ultracentrifugation and SEC have been used to separate these capsids. However, good separation of the large and small particles with these methods is never achieved. In the present study, we employed a simple, fast, and cost-effective method to separate the T = 3 and T = 4 HBcAg capsids by using native agarose gel electrophoresis followed by an electroelution method (NAGE-EE). This is a direct, fast, and economic method for isolating the large and small HBcAg particles homogenously based on the hydrodynamic radius of the spherical particles. Dynamic light scattering analysis demonstrated that the T = 3 and T = 4 HBcAg capsids prepared using the NAGE-EE method are monodisperse with polydispersity values of ∼15% and ∼13%, respectively. ELISA proved that the antigenicity of the capsids was not affected in the purification process. Overall, NAGE-EE produced T = 3 and T = 4 capsids with a purity above 90%, and the recovery was 34% and 50%, respectively (total recovery of HBcAg is ∼84%), and the operation time is 15 and 4 times lesser than that of the sucrose density gradient ultracentrifugation and SEC, respectively.
Matched MeSH terms: Hepatitis B Core Antigens/biosynthesis; Hepatitis B Core Antigens/genetics; Hepatitis B Core Antigens/isolation & purification*; Hepatitis B Core Antigens/chemistry; Hepatitis B virus/chemistry*