Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0019158 (hepatitis)
 30,205 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

We have determined the complete nucleotide sequence of an infectious cloned genome of ground squirrel hepatitis virus (GSHV), a nonpathogenic member of the hepadnavirus group. The genome is 3,311 base pairs long and contains the major open reading frames described for the related human and woodchuck hepatitis B viruses (HBV and WHV, respectively). These reading frames include genes for the major structural proteins (the surface and core antigens), unassigned open reading frames (A and B), the longer of which is presumed to encode the viral DNA polymerase, and an open reading frame preceding and continuous with the surface antigen gene. The arrangement of these open reading frames is similar to that encountered in the genomes of HBV and WHV: all of the reading frames are encoded on the same strand, they are positioned in the same fashion with respect to each other, and a large portion (at least 51%) of the genome can be translated in two reading frames. Comparisons of the predicted translational products of the three mammalian hepadnaviruses reveal 78% amino acid homology between the proteins of GSHV and WHV and 43% homology between those of GSHV and HBV. In addition, a perfect direct repeat of 10 to 11 base pairs, separated by ca. 46 to 223 base pairs, is present in the three mammalian viruses and in duck hepatitis B virus; the position of the repeats near the 5' termini of the two strands of virion DNA suggests a role in viral replication.
 ...
PMID:Nucleotide sequence of an infectious molecularly cloned genome of ground squirrel hepatitis virus. 608 50

The serological markers of hepatitis B virus and serum alpha-fetoprotein (AFP) levels have been studied in 28 consecutive cases of fulminant hepatitis, correlating the data with survival. On admission, 20 patients were found to be positive for HBsAg and eight for anti-HBs. All anti-HBs-positive cases showed high titers of anti-HBc, and six patients were positive for specific anti-HBc-IgM. DNA polymerase activity was detected in serum of 11 HBsAg-positive (55%) and four anti-HBs-positive (50%) patients. HBeAg was detected in six (21.4%) subjects (five HBsAg-positive and one anti-HBs-positive), whereas anti-HBe was present in nine (32.1%) subjects (six HBsAg-positive and three anti-HBs-positive). AFP levels greater than 60 ng/ml were found in sera of 14 patients (50%). No significant difference was evidenced in the survival rate between HBsAg-positive and anti-HBs-positive and between HBeAg-positive and HBe Ag-negative patients. However, a statistically significant difference (P less than 0.05) in the survival rate was found in patients positive and negative for DNA polymerase activity and in those with AFP levels higher and lower than 60 ng/ml (P less than 0.005). Pathogenetic and prognostic significance of these findings are discussed.
 ...
PMID:Hepatitis B virus markers, alpha-fetoprotein and survival in fulminant viral hepatitis. 616 71

Six patients with chronic type B hepatitis were treated with adenine arabinoside 5'-monophosphate at a dosage of 10 to 15 mg per kg per day for 10 days. All demonstrated an immediate and marked decrease in serum hepatitis B virus DNA and DNA polymerase, and 5 of the 6 became negative for both markers by the end of the period of therapy. One patient remained negative for hepatitis B virus DNA and DNA polymerase when therapy was discontinued. This patient subsequently exhibited clinical, serum biochemical, and histological remission in disease activity concurrent with seroconversion from hepatitis B e antigen to antibody. In the remaining five patients, serum hepatitis B virus DNA and DNA polymerase returned to pretreatment values soon after therapy was stopped, and these patients demonstrated no significant changes in clinical, biochemical, serological, or histological features of the disease. Side effects of the therapy were mild and transient. These results suggest that a 10-day course of adenine arabinoside 5'-monophosphate is not adequate to induce permanent amelioration of infection and disease activity in the majority of patients with chronic type B hepatitis.
 ...
PMID:Adenine arabinoside 5'-monophosphate treatment of chronic type B hepatitis. 618 83

The efficient in vitro inhibition of hepatitis B virus DNA polymerase by trisodium phosphonoformate (PFA, INN: foscarnet sodium) and its low toxicity suggested that PFA could be used as a therapeutic agent for hepatitis B infection. PFA was also found to inhibit woodchuck hepatitis virus (WHV) DNA polymerase in vitro. As a model to test PFA's eventual effect, chronically WHV infected woodchucks were treated with PFA. The animals were treated twice daily in a dosage which gave a minimum serum level of PFA corresponding to an in vitro inhibiting effect on WHV DNA polymerase of about 40%. The concentration in liver tissue was found to be 15% below serum level. The amount of WHV particles in serum was followed by DNA polymerase assay. No effect on WHV production could be seen during 2 weeks' treatment. No change of the in vitro sensitivity to PFA of the WHV DNA polymerase was seen. These results indicate that the WHV associated DNA polymerase has no role in the production of viral particles.
 ...
PMID:No in vivo effect of trisodium phosphonoformate on woodchuck hepatitis virus production. 622 May 63

The principal properties of the DNA polymerases of woodchuck hepatitis virus and human hepatitis B virus were compared. The enzymes of both viruses exhibited optimal activities in the same range of pH, ionic strength, and MgCl2 concentration. Like human hepatitis B virus DNA polymerase, the woodchuck hepatitis virus DNA polymerase was strongly inhibited by phosphonoformic acid but not by phosphonoacetic acid and aphidicolin. Similar inhibition patterns for both enzymes were observed with arabinofuranosyl nucleotides (9-beta-D-arabinofuranosyladenine-5'-triphosphate, 1-beta-D-arabinofuranosylcytosine-5'-triphosphate, 1-beta-D-arabinofuranosylthymine-5'-triphosphate) and dideoxythymidine triphosphate, whereas no effect was obtained with corresponding nucleosides. The therapeutic significance of these results and the relevance of the woodchuck as an experimental animal model for the study of human hepatitis B virus infections are discussed.
 ...
PMID:Comparison of properties of woodchuck hepatitis virus and human hepatitis B virus endogenous DNA polymerases. 623 85

Two human hypatitis viruses have been identified and characterized, but one or more additional agents exist. Hepatitis B virus (HBV) is a complex 42-nm predominantly double-stranded DNA virus with distinct surface and core antigens and an endogenous DNA polymerase. Hepatitis A virus (HAV) is a 27-nm RNA virus with enterovirus-like properties. Progressively more sensitive and specific immunologic assays have been applied to the study of viral hepatitis and are available for routine diagnostic purposes. As a result we recognize distinct serologic response patterns to infection, new antigenic markers, biochemical-biophysical characteristics of the viruses, and their epidemiologic features. Recombinant DNA technology has permitted the cloning of HBV genetic material and gene products in E. coli, but the virus has not been cultivated in vitro. In contrast, successful in vitro cultivation of HAV has finally been accomplished. Application of sensitive serologic tests for HAV and HBV has revealed that "non-A, non-B" agents account for a substantial proportion of transfusion-associated hepatitis as well as hepatitis occurring in the absence of percutaneous exposure. These agents have been transmitted to chimpanzees, and several putative virus antigen-antibody systems have been described; however, a specific association between these virus antigens and non-A, non-B hepatitis has not been established.
 ...
PMID:Hepatitis viruses: characterization and diagnostic techniques. 624 88

The livers of 33 captive woodchucks were examined histologically in 30 biopsy and 10 autopsy specimens and the findings were correlated with serum determinations for woodchuck hepatitis virus (WHV), surface antigen (WHsAg) and antibody (anti-WHs), and WHV DNA and DNA polymerase. The liver appeared normal in all 3 serum-negative animals, 7 of 16 with indeterminate WHV status, and 1 of 4 with anti-WHs, but not in 10 animals with WHsAg, WHV DNA, and DNA polymerase. Mild hepatic inflammation was found in 7 woodchucks with indeterminate status, 4 with anti-WHs, and 2 with each marker of WHV infection. Significant inflammation was found in 2 of indeterminate status and 4 with every marker, whereas more severe lesions (2 of chronic active type) occurred, almost always in autopsy specimens, in 8 animals with every marker. Eight of 10 animals with all markers had orcein-positive inclusions (Shikata's technique) and 6 had hepatocellular carcinoma associated with acute and chronic hepatic inflammation and, usually, neoplastic nodules in the noncarcinomatous parenchyma. Features distinguishing the woodchuck lesion from human hepatitis B disease were: association of carcinoma with acute hepatic inflammation (but not with cirrhosis) and DNA polymerase in the serum; transition to carcinoma from neoplastic nodules; conspicuous plasma-cellular reaction of hepatic inflammation, and hematopoietic cells in the tumor. Significant hepatic lesions in the woodchucks were regularly associated with serum WHsAg, WHV DNA, and DNA polymerase. In contrast to man, hepatocellular carcinoma in woodchucks was regularly associated with these markers of active viral replication. The nature of the orcein-positive inclusions requires elucidation, although they may assist in screening for similar viruses in other species. The woodchuck may help in the study of the relation between hepatocellular carcinoma and hepatitis B, including the possibility of cocarcinogenic factors.
 ...
PMID:Woodchuck hepatitis and hepatocellular carcinoma: correlation of histologic with virologic observations. 626 81

The structure of the encapsidated DNA genome of ground squirrel hepatitis virus (GSHV) has been examined by restriction endonuclease cleavage, nucleic acid hybridization, and molecular cloning. GSHV virion DNA is a relaxed circular molecule of approximately 3,200 bases in length; most molecules harbor an extensive single-stranded region which is largely confined to one-half of the genome. The full-length viral DNA strand is covalently bound to protein. The single-stranded region can be repaired in vitro by the action of the endogenous virion polymerase, exogenously added DNA polymerase from avian myeloblastosis virus, or both. Restriction enzyme cleavage of viral DNA from different isolates demonstrated that multiple variants of GSHV exist in nature. The genomes of two such strains have been cloned in Escherichia coli, and their physical maps have been determined. Nucleic acid hybridization studies revealed that the strains share sequence homology with the DNA of human hepatitis B virus. Regions homologous to the coding regions for the surface and core antigens of human hepatitis B virus have been localized on the GSHV chromosome. Molecular cloning experiments have also led to the identification of a region of the viral genome which is altered in a procaryotic host.
 ...
PMID:Virion DNA of ground squirrel hepatitis virus: structural analysis and molecular cloning. 629 98

Hepatitis B virus (HBV) markers were measured in 83 immunosuppressed renal transplant patients who were followed for periods of 2 to 15 years. Sixty-nine patients were negative for HBsAg before transplantation, of whom 14 were positive for anti-HBs. The remaining 14 patients were HBsAg positive prior to transplantation. Eighteen patients were identified as being HBsAg positive during the follow-up period. Four patients acquired primary type B hepatitis; one died of submassive hepatic necrosis and the remaining three became chronic HBV carriers with positive HBeAg, DNA polymerase, and HBV DNA. Several patterns of HBV expression were observed in HBsAg-positive patients. Four patients were HBsAg, HBeAg, DNA polymerase, and HBV DNA positive prior to transplantation, and these markers persisted. Reactivation of HBV replication occurred in eight patients, seven of whom were HBsAg positive and HBeAg and anti-HBe negative originally; one patient was anti-HBc positive. A single patient was HBsAg and anti-HBe positive and remained so for 22 months. The remaining previously HBsAg-positive patient is currently HBsAg negative. These serological data suggest that reactivation of HBV replication or continued hepatitis B virion replication occurs as commonly or more commonly than de novo infection in renal transplant recipients. The presence of HBeAg in serum predisposes to long-term Dane particle expression in immunosuppressed patients, whereas anti-HBe-positive carriers may not always be susceptible to reactivation of HBV replication despite immunosuppression.
 ...
PMID:Natural history of hepatitis B virus infection in renal transplant recipients--a fifteen-year follow-up. 634 Nov 96

Sera from 588 woodchucks were assayed for woodchuck hepatitis virus (WHV) markers using hepatitis B virus (HBV) reagents which have cross-reactivity with WHV markers. Twenty per cent of these woodchucks, trapped in Delaware, Maryland and Pennsylvania, had WHsAg; 50% of these had DNA polymerase. There are areas of high and low endemicity within these states. Female woodchucks may have a higher incidence of WHV markers than do males. Woodchuck hepatitis surface antigen (WHsAg) and anti-WHc often occur together but less commonly than HBsAg and anti-HBc do in human HBV infection. Experimental infection of woodchucks with WHV produced a prolonged infection (up to 40 weeks). WHsAg and DNA polymerase appeared to be more reliable indicators of infectivity than anti-WHc, woodchuck hepatitis e antigen (WHeAg) or anti-WHe. WHeAg was not detected throughout this period of infection, while anti-WHe appeared late in two of three experimentally infected animals. Four male and four female woodchucks which developed primary hepatocellular carcinoma in captivity were analyzed for WHV markers throughout their period of confinement. Seven were WHsAg and anti-WHc positive when captured. The animal that was free of WHV markers on capture converted to the WHsAg and anti-WHc positive state prior to the development of primary hepatocellular carcinoma. One primary hepatocellular carcinoma animal produced WHeAg and none anti-WHs or anti-WHe.
 ...
PMID:Woodchuck hepatitis virus: experimental infection and natural occurrence. 638 96


<< Previous 1 2 3 4 5 6 7 8 9 10 Next >>