Hepatitis B infection and aflatoxin biomarker levels in Gambian children.
(33/729)
OBJECTIVES: To examine the relationship between hepatitis B virus (HBV) infection and biomarkers of aflatoxin exposure in West African children. METHODS: Sera from 444 children aged 3-4 years who were selected to be representative of their communities were analysed for aflatoxin-albumin (AF-alb) adducts and markers of hepatitis B infection. RESULTS: There was large interindividual variation in adduct levels (range: 2.2 to 459 pg AF-lysine eq./mg albumin). Adduct level was strongly correlated with season, with an approximately twofold higher mean level in the dry season than the wet. Geometric mean adduct levels in uninfected children, chronic carriers and acutely infected children were 31.6 (n = 404), 44.9 (n = 34) and 96.9 (n = 6) pg/mg, respectively. The relationship of AF-alb level to ethnicity, month of sampling and HBV status was examined in a multiple regression model. Month of obtaining the blood sample (P = 0.0001) and HBV status (P = 0.0023) each made a highly significant contribution to the model; the high AF-alb levels were particularly associated with acute infection. Elevated serum transaminase levels were significantly (P < 0.002) associated with HBV status, with acutely infected children having the highest levels. Ethnicity was not significantly associated with AF-alb adduct levels in the model (P = 0.09). CONCLUSIONS: HBV infection and month of sampling both significantly influence AF-alb adduct levels. The effect of seasonality on adducts was also observed in a previous study of 347 Gambian adults, although there was no correlation between adduct level and HBV status in that population. This difference between children and adults may reflect a more severe effect of HBV infection, particularly acute infection, in childhood on hepatic AF metabolism. (+info)
Prevalence of hepatitis B anti-core antibody in the Republic of Ireland.
(34/729)
The aim of this study was to estimate the prevalence of hepatitis B exposure in the population of the Republic of Ireland, by measuring the prevalence of hepatitis B anti-core antibody in oral fluid collected by postal survey. A random multi-stage stratified sample of Irish households was obtained, using the Irish electoral register as the sampling frame. A total of 962 households were selected, and a household response rate of 60.4% was achieved. Oral fluid specimens totalling 1714 were tested for antibody to hepatitis B core antigen (anti-HBc), using an Immune Capture Enzyme Immuno-Assay. Five specimens (0.29%) were found to contain anti-HBc. Adjusting for study design, the estimated anti-HBc prevalence in the Republic of Ireland is 0.51%. This study demonstrates that self-collection of oral fluid samples is acceptable to the public, and based upon the data generated, that the Republic of Ireland has a low prevalence of hepatitis B infection. (+info)
Nuclear covalently closed circular viral genomic DNA in the liver of hepatocyte nuclear factor 1 alpha-null hepatitis B virus transgenic mice.
(35/729)
The role of hepatocyte nuclear factor 1alpha (HNF1 alpha) in the regulation of hepatitis B virus (HBV) transcription and replication in vivo was investigated using a HNF1 alpha-null HBV transgenic mouse model. HBV transcription was not measurably affected by the absence of the HNF1 alpha transcription factor. However, intracellular viral replication intermediates were increased two- to fourfold in mice lacking functional HNF1 alpha protein. The increase in encapsidated cytoplasmic replication intermediates in HNF1 alpha-null HBV transgenic mice was associated with the appearance of nonencapsidated nuclear covalently closed circular (CCC) viral genomic DNA. Viral CCC DNA was not readily detected in HNF1 alpha-expressing HBV transgenic mice. This indicates the synthesis of nuclear HBV CCC DNA, the proposed viral transcriptional template found in natural infection, is regulated either by subtle alterations in the levels of viral transcripts or by changes in the physiological state of the hepatocyte in this in vivo model of HBV replication. (+info)
Quantitative hepatitis B virus DNA testing for the early prediction of the maintenance of response during lamivudine therapy in patients with chronic hepatitis B.
(36/729)
To determine whether a dramatic decrease in hepatitis B virus (HBV) DNA levels within the first months of lamivudine therapy can predict the emergence of YMDD variants in patients with chronic hepatitis B, quantitative testing was done every 3 months on serum samples from 35 patients who were treated with lamivudine for >1 year. The decline in HBV DNA levels from baseline to month 3 was higher in 22 responders than in 13 nonresponders (mean+/-SD, 4.16+/-1.06 vs. 2.88+/-1.77 log(10) copies; P=.002), whereas no differences were observed in patients with and without YMDD variants at 1 year of therapy. At 3 months, HBV DNA was undetectable in 77% of the responders, whereas, after 1 year, it was undetectable in 23% of nonresponders, 40% of patients with YMDD variants, and 74% of those without variants. Therefore, quantitative HBV DNA testing is very useful in deciding whether to continue therapy, because of the low likelihood of response in patients who remain HBV DNA positive at month 3 of treatment. (+info)
Prevalence of antibodies to hepatitis B core antigen in blood donors in the middle West region of Brazil.
(37/729)
The prevalence of antibodies to hepatitis B core antigen in 552 prime blood donors was of 9.4%. The majority (71.2%) has antibodies to hepatitis B surface antigen. The hepatitis B surface antigen was present in 0.7%, all of them antibodies to hepatitis B core antigen positive. (+info)
Isolated presence of antibody to hepatitis B core antigen in injection drug users: do they need to be vaccinated?
(38/729)
In a study of 497 injection drug users who had isolated presence of antibody to hepatitis B core antigen (anti-HBc) at the time of enrollment, 404 (81%) retained this condition after a mean of 49 months of follow-up, during which time no new hepatitis B surface antigen marker was detected. These findings support the hypothesis that patients with isolated presence of anti-HBc have strong resistance to reinfection and do not need vaccination. (+info)
Prevalence of hepatitis B infection markers in Lebanese children: the need for an expanded programme on immunization.
(39/729)
This multi-centre, cross-sectional study was designed to reveal the present status of hepatitis B infection markers among Lebanese children, and provide recommendations regarding childhood immunization policies. A total of 841 children, aged between 6 months and 6.5 years, were enrolled from Lebanon's five districts. Their sera were tested for hepatitis B surface antigen and hepatitis B core IgG. The overall prevalence of hepatitis B virus infection markers was 0.8% with increasing age-specific rates from 0% at 6 months to 1.3 % at > 5 years. There was no statistically significant association between the presence of hepatitis B markers and family characteristics or risk factors for infection. The highest prevalence rates were among children from Beirut suburbs (2.9 %) and South Lebanon (1.6%). The risk of horizontal transmission of hepatitis B to uninfected children increased substantially after the age of 2 years. An expanded programme on immunization that integrates hepatitisB vaccine during the first year of life is needed. (+info)
Demonstration of hepatitis B e antigen (HBeAg) in association with intact Dane particles.
(40/729)
Mild detergent treatment (0.1% Sarkosyl-0.1% beta-mercaptoethanol) of Dane particle-rich fraction from human serum resulted in the release of core particles together with HBe antigen activity when examined by the reversed passive haemagglutination method. Furthermore, when the core particles isolated by the above procedure were exposed to stronger detergent (1% Sarkosyl-0.1% beta-mercaptoethanol), additional HBe antigen activity was released only from intact core particles with DNA polymerase activity and not from empty core particles. (+info)