Avian and Mammalian hepadnaviruses have distinct transcription factor requirements for viral replication. (1/15)

Hepadnavirus replication occurs in hepatocytes in vivo and in hepatoma cell lines in cell culture. Hepatitis B virus (HBV) replication can occur in nonhepatoma cells when pregenomic RNA synthesis from viral DNA is activated by the expression of the nuclear hormone receptors hepatocyte nuclear factor 4 (HNF4) and the retinoid X receptor alpha (RXR alpha) plus peroxisome proliferator-activated receptor alpha (PPAR alpha) heterodimer. Nuclear hormone receptor-dependent HBV replication is inhibited by hepatocyte nuclear factor 3 (HNF3). In contrast, HNF3 and HNF4 support duck hepatitis B virus (DHBV) replication in nonhepatoma cells, whereas the RXR alpha-PPAR alpha heterodimer inhibits HNF4-dependent DHBV replication. HNF3 and HNF4 synergistically activate DHBV pregenomic RNA synthesis and viral replication. The conditions that support HBV or DHBV replication in nonhepatoma cells are not able to support woodchuck hepatitis virus replication. These observations indicate that avian and mammalian hepadnaviruses have distinct transcription factor requirements for viral replication.  (+info)

Hepatitis B virus taxonomy and hepatitis B virus genotypes. (2/15)

Hepatitis B virus (HBV) is a member of the hepadnavirus family. Hepadnaviruses can be found in both mammals (orthohepadnaviruses) and birds (avihepadnaviruses). The genetic variability of HBV is very high. There are eight genotypes of HBV and three clades of HBV isolates from apes that appear to be additional genotypes of HBV. Most genotypes are now divided into subgenotypes with distinct virological and epidemiological properties. In addition, recombination among HBV genotypes increases the variability of HBV. This review summarises current knowledge of the epidemiology of genetic variability in hepadnaviruses and, due to rapid progress in the field, updates several recent reviews on HBV genotypes and subgenotypes.  (+info)

Hepatitis A vaccination in chronic liver disease: is it really required in a tropical country like India? (3/15)

Vaccination against hepatitis A virus (HAV) has been recommended in patients with chronic liver disease to prevent any decompensation due to superinfection. This may not hold good in high endemic areas for hepatitis A like India. The aim of this study was to find out the seroprevalence of anti-HAV antibodies in patients with chronic liver disease and to justify the need for vaccination against hepatitis A virus in these patients. One hundred and thirty three consecutive patients with cirrhosis of liver attending Gastroenterology department of our Institute between June 2004 and June 2005 were enrolled. Seventy-five healthy persons were taken as controls. The diagnosis of cirrhosis was based on clinical profile, biochemical, radiological (ultrasound abdomen) and endoscopic findings. The etiology of cirrhosis was based on presence of viral markers, history of significant alcohol consumption, autoimmune and metabolic workup. All patients and controls were tested for antiHAV (total) antibodies using commercially available enzyme-linked immunosorbent assay kits. Data from patients and control group were compared by unpaired 't' test and Chi square test. All subjects were in the age group 11 to 75 years. Etiology of chronic liver disease was as follows: HBV- 29.3%, HCV - 14.28%, HBV+HCV dual -1.5%, alcohol- 21.8%, Cryptogenic -23.3%, Wilson"s Disease -1.5% and Budd chiari -1.5%. The prevalence of HAV was 93.2% in patients with cirrhosis of liver and 94.6% in controls. The prevalence was almost similar irrespective of the etiology. In view of high seroprevalence of HAV antibodies among cirrhotic patients in our study and the high cost of the vaccine, the hepatitis A vaccination may not be routinely required in this part of the world.  (+info)

Hepatitis B immunoglobulin and Lamivudine improve hepatitis B-related outcomes after liver transplantation: meta-analysis. (4/15)

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Prevalence of a virus similar to human hepatitis B virus in swine. (5/15)

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Seroprevalence of HIV, HBV, HCV and syphilis in blood donors in Southern Haryana. (6/15)

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Exposure to risk factors for hepatitis B and C viruses among primary school teachers in Karachi. (7/15)

INTRODUCTION: The study aimed to determine hepatitis B vaccination status and assess the exposure of risk factors for hepatitis B and C among primary schoolteachers in Karachi, Pakistan. METHODOLOGY: In two hundred school teachers from 30 primary schools in Karachi participated in the study between January and June 2008 by completing an anonymous, self-administered questionnaire. Exposure to and knowledge of hepatitis B and C were assessed, as well as mode of transmission and prevention. The percentage of vaccinated and non-vaccinated teachers was also estimated. RESULTS: Only 73 (36.5%) respondents were vaccinated against HBV. Nine percent (17) of the teachers had received more than 10 therapeutic injections while about 56% (101) took between 5-10 injections per annum. Fifteen (8%) of the teachers confirmed they had been injected with re-used syringes. More than 8% (17) of participants' family members were suffering from hepatitis B or C, while 10% (20) of family members had died of liver diseases without any known history. More than 13% (27) of participants shared razors, brushes, cigarettes and hukahs. Statistically significant difference was also observed in risk factors of hepatitis B and C among male and female respondents. CONCLUSION: Hepatitis B vaccination among school teachers of Karachi was around 37% with a high use of therapeutic injections and syringe reuse. Health awareness programs and educational workshops are needed for teachers, who can later educate the children.  (+info)

Protein X of hepatitis B virus: origin and structure similarity with the central domain of DNA glycosylase. (8/15)

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