| serological relationship of woodchuck hepatitis virus to human hepatitis b virus. | two antigenic systems of the woodchuck hepatitis virus have been identified. the relationship between viral antigens of the woodchuck hepatitis virus and the human hepatitis b virus was determined by using immunoprecipitation, hemagglutination, and immune electron microscopy techniques. antigens found on the cores of the two viruses were cross-reactive. lack of cross-reactivity between the surface antigens of the two viruses in immunodiffusion experiments suggested that the major antigenic deter ... | 1979 | 94359 |
| a virus similar to human hepatitis b virus associated with hepatitis and hepatoma in woodchucks. | particles with properties similar to those associated with human hepatitis b were found in serum from woodchucks with chronic hepatitis and hepatocellular carcinoma. it is suggested that woodchuck hepatitis virus is a second member of a novel class of viruses represented by the human hepatitis b virus. | 1978 | 212758 |
| direct immunofluorescence testing for immunoglobulin deposits in haired skin, nasal planum and footpads of woodchuck hepatitis virus-infected woodchucks with chronic hepatitis and multiple hepatocellular carcinomas. | the purpose of this study was to determine the frequency of immunoglobulin deposition in the haired skin, footpads, and nasal planums of 10 whv-infected woodchucks with chronic hepatitis and hepatocellular carcinoma and compare these results with those reported in humans. immunoglobulin deposition was detected in the skin samples of 3 of 10 woodchucks. granular deposits were revealed in the superficial dermal blood vessels of the nasal planum, lateral thoracic skin, and footpads in 1 animal each ... | 1992 | 1310926 |
| multiple rearrangements and activated expression of c-myc induced by woodchuck hepatitis virus integration in a primary liver tumour. | woodchuck hepatitis virus (whv) is a small, partially double-stranded dna virus. like the related human hepatitis b virus (hbv), whv induces acute and chronic hepatitis and hepatocellular carcinoma (hcc) in its natural host. whv dna integration into c-myc and n-myc, resulting in deregulated expression of these genes, has been described previously in woodchuck hcc. we have analysed a woodchuck liver tumour in which whv dna was integrated in the c-myc gene. the virus insertion provoked multiple al ... | 1992 | 1317604 |
| hepadnavirus integration: mechanisms of activation of the n-myc2 retrotransposon in woodchuck liver tumors. | in persistent hepadnavirus infections, a distinctive feature of woodchuck hepatitis virus (whv) is the coupling of frequent viral integrations into myc family genes with the rapid onset of primary liver tumors. we have investigated the patterns of whv dna insertion into n-myc2, a newly identified retroposed oncogene, in woodchuck hepatomas resulting from either natural or experimental infections. in both cases, integrated viral sequences were preferentially associated with the n-myc2 locus. in m ... | 1992 | 1323693 |
| mammalian hepatitis b viruses and primary liver cancer. | hepatitis b virus is a major etiologic agent in the development of human hepatocellular carcinoma, but the precise role of the virus in the tumorigenic process is still unclear. recent studies of naturally occurring animal models, such as woodchucks and squirrels infected with hepatitis b-like viruses (hepadnaviruses) have revealed different oncogenic strategies and outlined the predominant role of myc genes in rodent hepatomas. higher oncogenicity of woodchuck hepatitis virus has been correlate ... | 1992 | 1335794 |
| the role of hepatitis b virus in the development of primary hepatocellular carcinoma: part i. | chronic infections with hepatitis b virus (hbv) of humans and animal hepadnavirus infections in their natural hosts are strongly associated with primary hepatocellular carcinoma (hcc). although viral integrations are found in cells of many hcc, no general viral-specific hepatocarcinogenic mechanism for hepadnaviruses has been identified. in approximately one half of hcc in woodchuck hepatitis virus (whv) infected woodchucks, viral integrations near the c-myc or n-myc genes have been reported whi ... | 1992 | 1336678 |
| altered glycosylation of alpha-fetoprotein in hepadnavirus-induced hepatocellular carcinoma of the woodchuck. | altered glycosylation of alpha-fetoprotein (afp) has been proposed as a marker of hepatocellular carcinoma (hcc) in humans. the lectin-binding properties of woodchuck afp were investigated to determine if woodchuck hepatitis virus (whv)-induced hccs are also accompanied by changes in afp glycosylation. ninety-eight to 100% of the afp from normal, whv-free woodchucks with physiologic afp elevations and from whv-carrier woodchucks with hcc bound to concanavalin a, indicating that virtually all of ... | 1992 | 1373341 |
| viral spliced rna are produced, encapsidated and reverse transcribed during in vivo woodchuck hepatitis virus infection. | by the use of reverse transcription followed by polymerase chain reaction (rt-pcr), we have identified one shorter than full-length, pregenomic viral rna species in liver samples of woodchucks chronically infected with the woodchuck hepatitis virus (whv). the spliced whv rna of about 2.4 kb in length was cloned and partially sequenced. the splicing donor and acceptor sites of this novel rna are located, respectively, 130 nucleotides downstream of the atg initiation codon of the core gene and 21 ... | 1992 | 1382340 |
| microscopic anatomy of the skin of the woodchuck (marmota monax): comparison of woodchuck hepatitis virus-infected and non-infected animals. | thirty-three woodchucks were used in this study. seventeen animals were healthy adults, not infected with woodchuck hepatitis virus (whv); 10 were healthy adults infected with whv; 4 were noninfected neonates; 2 were infected neonates. within the 4 groups of woodchucks, no histologic differences were detected on the basis of sex or age. neither were histologic findings different between infected and noninfected woodchucks of similar ages. the average thickness of skin (as measured from the skin ... | 1992 | 1424633 |
| skin disorders of the laboratory woodchuck (marmota monax): a retrospective study of 113 cases (1980-1990). | an 11-year retrospective study was conducted on the dermatoses occurring in 113 woodchucks from a colony at the college of veterinary medicine at cornell university. bacterial dermatitis was the most common dermatologic disorder, accounting for 70.2% of the cases. the highest incidence of bacterial dermatitis occurred in september/october prior to hibernation and in february/march during the breeding season. other dermatoses observed during the study period included taenia crassiceps infection, ... | 1992 | 1424634 |
| lack of pre-c region mutation in woodchuck hepatitis virus from seroconverted woodchucks. | woodchuck hepatitis virus, which shares a large degree of homology with human hbv, was examined for indications of mutational variants. no alteration in the pre-c region was found, but as in hbv, viral dna could still be detected by pcr after seroconversion to anti-whe. | 1992 | 1450731 |
| immunosuppression with cyclosporine during the incubation period of experimental woodchuck hepatitis virus infection increases the frequency of chronic infection in adult woodchucks. | the immunosuppressive agent cyclosporine was given to adult woodchucks during acute experimental infection with woodchuck hepatitis virus (whv). all 17 woodchucks given whv alone or with a vehicle resolved the infection (i.e., zero chronicity), but when cyclosporine was given throughout the incubation and acute phases of infection (0-12 or 14 weeks; n = 12), the rate of chronic infection increased to 92%. when cyclosporine was given only during the incubation period (0-4 weeks; n = 10) or only d ... | 1992 | 1500746 |
| the precore gene of the woodchuck hepatitis virus genome is not essential for viral replication in the natural host. | a number of naturally occurring hepatitis b virus mutants that cannot synthesize the virus precore protein have been identified. such mutants have been associated with more severe forms of hepatitis, including fulminant hepatitis. the most common mutation observed is a substitution of g to a in the distal precore gene that converts a codon specifying trp (tgg) to a termination codon (tag). using oligonucleotide-directed mutagenesis, we have produced the same point mutation in the precore gene of ... | 1992 | 1501300 |
| assembly of hepatitis delta virus particles. | hepatitis delta virus (hdv) is a subviral satellite of hepatitis b virus (hbv). since the rna genome of hdv can replicate in cultured cells in the absence of hbv, it has been suggested that the only helper function of hbv is to supply hbv coat proteins in the assembly process of hdv particles. to examine the factors involved in such virion assembly, we transiently cotransfected cells with various hepadnavirus constructs and cdnas of hdv and analyzed the particles released into the medium. we rep ... | 1992 | 1548764 |
| frequent amplification of c-myc in ground squirrel liver tumors associated with past or ongoing infection with a hepadnavirus. | persistent infection with hepatitis b virus (hbv) is a major cause of hepatocellular carcinoma (hcc) in humans. hcc has also been observed in animals chronically infected with two other hepadnaviruses: ground squirrel hepatitis virus (gshv) and woodchuck hepatitis virus (whv). a distinctive feature of whv is the early onset of woodchuck tumors, which may be correlated with a direct role of the virus as an insertional mutagen of myc genes: c-myc, n-myc, and predominantly the woodchuck n-myc2 retr ... | 1992 | 1570307 |
| spliced rna of woodchuck hepatitis virus. | polymerase chain reaction was used to investigate rna splicing in liver of woodchucks infected with woodchuck hepatitis virus (whv). two spliced species were detected, and the splice junctions were sequenced. the larger spliced rna has an intron of 1300 nucleotides, and the smaller spliced sequence shows an additional downstream intron of 1104 nucleotides. we did not detect singly spliced sequences from which the smaller intron alone was removed. control experiments showed that spliced sequences ... | 1992 | 1604814 |
| effects of 2'-fluorinated arabinosyl-pyrimidine nucleosides on duck hepatitis b virus dna level in serum and liver of chronically infected ducks. | the 2'-fluorinated arabinosyl-pyrimidine nucleosides, 1-(2'-deoxy-2'-fluoro-beta-d-arabinofuranosyl)-5-iodocytosine (fiac) and 1-(2'-deoxy-2'-fluoro-beta-d-arabinofuranosyl)-5-methyluracil (fmau), are new antiviral compounds with in vitro inhibitory activity against the dna polymerase of hepadnaviruses. those compounds also induced permanent inhibition of viral replication in woodchucks chronically infected by woodchuck hepatitis virus. the effects of these antiviral compounds were assessed in d ... | 1992 | 1629711 |
| immunopathology of glomerulonephritis associated with chronic woodchuck hepatitis virus infection in woodchucks (marmota monax). | retrospective analysis of necropsy findings of 705 woodchucks was performed to determine the prevalence and morphology of immune-mediated glomerulonephritis, its relationship to woodchuck hepatitis virus (whv) infection, and the presence of major whv antigens. twenty-six woodchucks had glomerular lesions. renal tissue of the 26 animals was evaluated histologically and immunohistochemically for immune-mediated glomerulonephritis. of these 26 animals, immune-mediated glomerulonephritis was diagnos ... | 1992 | 1632459 |
| nitrite and nitrosamine synthesis by hepatocytes isolated from normal woodchucks (marmota monax) and woodchucks chronically infected with woodchuck hepatitis virus. | hepatocytes isolated from woodchucks (marmota monax) were shown to produce nitrite in vitro from l-arginine after stimulation with lipopolysaccharide (lps). hepatocytes isolated from woodchucks that were chronic carriers of woodchuck hepatitis virus formed twice as much nitrite as hepatocytes from noninfected animals. nitrite synthesis by hepatocytes was directly related to l-arginine and lps concentrations in the tissue culture medium and reached a plateau at 0.5 mm l-arginine and 1.0 microgram ... | 1992 | 1638528 |
| full-length and truncated versions of the hepatitis b virus (hbv) x protein (px) transactivate the cmyc protooncogene at the transcriptional level. | the products of the human hepatitis b virus (hbv) and woodchuck hepatitis b virus x genes (pxs) transactivate homologous and heterologous genes including the hbv-x and core promoters, the human immunodeficiency viruses 1 (hiv-1) and 2 (hiv-2) long terminal repeats and the beta interferon regulatory sequences. we report here that px is also able to influence the expression of both extrachromosomal transfected c-myc regulatory sequences and endogenous c-myc gene. px acts by increasing transcriptio ... | 1991 | 1645550 |
| [hepatitis b virus and hepatocellular carcinoma]. | hepatocellular carcinomas in woodchuck were characterized for woodchuck hepatitis virus integration near c-myc oncogene. in one tumor, viral integration resulted in overexpression of a c-myc viral cotranscript. in a second tumor, viral insertion, 600 bp upstream of c-myc exon 1, was associated with increased levels of normal c-myc mrna. these results demonstrate that integration of woodchuck hepatitis virus near a proto-oncogene can contribute to the genesis of liver tumors. from a comparison of ... | 1991 | 1650625 |
| analysis of insulin-like growth factor ii (igf-ii) expression in neoplastic nodules and hepatocellular carcinomas of woodchucks utilizing in situ hybridization and immunocytochemistry. | hepatocarcinogenesis in woodchucks that are persistently infected with woodchuck hepatitis virus (whv) follows a progressive course characterized by foci of altered hepatocytes, benign neoplastic nodules and finally hepatocellular carcinoma (hcc). in situ hybridization studies have demonstrated that insulin-like growth factor ii (igf-ii) is expressed in most hccs in woodchucks but that the patterns of expression are variable from tumor to tumor. in some cases, expression of igf-ii is high throug ... | 1991 | 1657428 |
| alpha-fetoprotein in the woodchuck model of hepadnavirus infection and disease: immunochemical analysis of woodchuck alpha-fetoprotein and measurement in serum by quantitative monoclonal radioimmunoassay. | woodchuck hepatitis virus infection of the eastern woodchuck represents a useful model for the study of hepatitis b virus infection and disease in humans, including hepatocellular carcinoma. in man, hepatocellular carcinoma is frequently detected and monitored using assays for serum alpha-fetoprotein. to study the relationship between alpha-fetoprotein and woodchuck hepatitis virus-induced hepatocellular carcinoma in the woodchuck model, we produced a monoclonal antibody to woodchuck alpha-fetop ... | 1990 | 1693355 |
| alpha-fetoprotein in the woodchuck model of hepadnavirus infection and disease: normal physiological patterns and responses to woodchuck hepatitis virus infection and hepatocellular carcinoma. | persistent infection of the eastern woodchuck (marmota monax) with the woodchuck hepatitis virus (whv) produces disease sequelae similar to those observed in humans with persistent hepatitis b virus infection, including hepatocellular carcinoma (hcc). to further characterize serological markers of hcc in the woodchuck, serum alpha-fetoprotein (afp) was measured under normal physiological conditions and following infection with whv. serum afp was elevated in association with whv-induced hepatitis ... | 1990 | 1701355 |
| adenine arabinoside monophosphate and acyclovir monophosphate coupled to lactosaminated albumin reduce woodchuck hepatitis virus viremia at doses lower than do the unconjugated drugs. | the woodchuck was selected to study the efficacy of liver-targeted antiviral drugs on hepadnavirus replication. nineteen woodchucks chronically infected with woodchuck hepatitis virus were treated with adenine arabinoside monophosphate or acyclovir monophosphate, either free or conjugated with the liver-targeting molecule lactosaminated human serum albumin. circulating woodchuck hepatitis virus dna levels remained unchanged in untreated animals and in those receiving the carrier lactosaminated h ... | 1991 | 1712338 |
| demonstration of woodchuck hepatitis virus infection of peripheral blood mononuclear cells by flow cytometry and polymerase chain reaction. | peripheral blood mononuclear cells (pbmcs) from 10 woodchuck hepatitis virus (whv)-infected woodchucks were examined for the presence of whv surface (whs) and core (whc) antigens (whsag and whcag) by cytofluorometry using fluorescein isothiocyanate-conjugated anti-whs and anti-hbc-purified immunoglobulins from woodchuck and human sera. the presence of viral dna and rna was detected in the serum and pbmcs from the same blood samples by polymerase chain reaction (pcr) with two primer sets located ... | 1992 | 1730932 |
| animal models of hepatocellular carcinoma: hepadnavirus-induced liver cancer in woodchucks. | woodchuck hepatitis virus (whv), a member of the hepadnaviridae, is closely related to hepatitis-b virus (hbv) in its virus structure, genetic organization, and mechanism of replication. as with hbv in man, persistent whv infection is common in natural woodchuck populations and is associated with chronic hepatitis and hepatocellular carcinoma (hcc). experimental studies have established that whv causes hcc in woodchucks. chronic whv carriage as an outcome of experimental infection is a function ... | 1991 | 1751825 |
| [hepatitis b virus and hepatocellular carcinoma]. | hepatocellular carcinoma in woodchuck were characterized for woodchuck hepatitis virus integration nea c-myc oncogene. in one tumor, viral integration resulted in overexpression of a c-myc viral cotranscript. in a second tumor, viral insertion, 600 bp upstream of c-myc exon 1, was associated with increased levels of normal c-myc mrna. these results demonstrate that integration of woodchuck hepatitis virus near a proto-oncogene can contribute to the genesis of liver tumors. from a comparison of a ... | 1991 | 1772242 |
| cyclosporin a modulates the course of woodchuck hepatitis virus infection and induces chronicity. | immunosuppression is known to influence the state of chronic hepatitis b virus infection, and is thought to increase the risk of developing chronic infection in newly exposed individuals. cyclosporin a (csa), an immunosuppressive agent that inhibits th cell function, was administered to woodchucks chronically infected with woodchuck hepatitis virus (whv), and resulted in a decreased severity of chronic hepatitis and an increased viremia during the treatment. adult woodchucks inoculated with whv ... | 1991 | 1826706 |
| prevention of radioactive indicator and viral particle transmission with an ointment barrier. | to determine the efficacy of a lanolin-based gel in preventing radioactive particle and viral penetration. | 1991 | 1849933 |
| topoisomerase i-mediated integration of hepadnavirus dna in vitro. | hepadnaviruses integrate in cellular dna via an illegitimate recombination mechanism, and clonally propagated integrations are present in most hepatocellular carcinomas which arise in hepadnavirus carriers. although integration is not specific for any viral or cellular sequence, highly preferred integration sites have been identified near the dr1 and dr2 sequences and in the cohesive overlap region of virion dna. we have mapped a set of preferred topoisomerase i (topo i) cleavage sites in the re ... | 1991 | 1850018 |
| elevated formation of nitrate and n-nitrosodimethylamine in woodchucks (marmota monax) associated with chronic woodchuck hepatitis virus infection. | nitrate balance and n-nitrosodimethylamine (ndma) excretion were studied in woodchucks chronically infected with woodchuck hepatitis virus (whv). twenty-four-h urinary recovery of a bolus dose of [15n]nitrate was 54 +/- 12% in woodchucks. whv-infected animals formed 3-fold more nitrate endogenously than did control animals (p less than 0.01). treatment of whv-infected animals with escherichia coli lipopolysaccharide increased nitrate excretion 15-fold, while uninfected animals increased nitrate ... | 1991 | 1855209 |
| hepatitis delta virus cdna sequence from an acutely hbv-infected chimpanzee: sequence conservation in experimental animals. | hepatitis delta virus (hdv) rna was isolated from the serum of a chimpanzee acutely infected with hepatitis b virus (hbv) and superinfected with hdv. interference of hdv with hbv resulted in decreased hbv dna levels in the serum. this interference did not change the size of the two hbv specific rnas present in the liver of the chimpanzee. the complete cdna sequence of the hdv rna (5th passage) was determined. comparison of this cdna sequence with our previously published sequence (4th passage), ... | 1991 | 1940877 |
| polymerase-related polypeptides associated with woodchuck hepatitis core antigen (whcag) particles. | the woodchuck hepatitis virus (whv) polymerase (pol)-encoded polypeptide(s), obtained from purified virus nucleocapsid particles, have been characterized by western blotting. peptide antibodies to amino-terminal (residues 32-45, whv pol-6) and carboxy-terminal (residues 861-879, whv pol-1) sequences were used, in addition to monoclonal antibodies made from purified woodchuck hepatitis core antigen (whcag) particles. one of the monoclonal antibodies, wc pol-11, specifically bound whv pol-1. both ... | 1991 | 1984662 |
| production of polyclonal antibodies against the s and pres2 regions of woodchuck hepatitis virus: lack of detectable low glycosylated pres2 protein (gp33) in sera from infected animals. | polyclonal antibodies directed against the pres2 and s domains of the woodchuck hepatitis virus (whv) envelope proteins were prepared using synthetic peptides and fusion polypeptides as immunogens. they were tested by immunoblotting and immunoprecipitation of infected woodchuck sera and lysates of a eukaryotic cell line expressing whv envelope proteins. only one anti-peptide serum directed against the pres2 domain was reactive with whv envelope proteins, recognizing the pres2 and pres1 proteins ... | 1991 | 1993879 |
| woodchuck hepatitis virus is a more efficient oncogenic agent than ground squirrel hepatitis virus in a common host. | chronic infection with hepatitis b viruses (hepadnaviruses) is a major cause of hepatocellular carcinoma (hcc), but the incubation time varies from 1 to 2 years to several decades in different host species infected with indigenous viruses. to discern the influence of viral and host factors on the kinetics of induction of hcc, we exploited the recent observation that ground squirrel hepatitis virus (gshv) is infectious in woodchucks (c. seeger, p. l. marion, d. ganem, and h. e. varmus, j. virol. ... | 1991 | 2002538 |
| direct immunofluorescence testing of haired skin, nasal planum, and footpads of clinically normal woodchuck hepatitis virus-infected and non-infected woodchucks. | the purpose of this study was to determine the frequency of immunoreactant deposition in the skin, footpad, and nasal planum of 10 clinically normal, non whv-infected woodchucks. the second part of the study investigated the frequency of immunoreactant deposition at the same sites in clinically normal, whv-infected woodchucks, and compared these results with those reported in humans. direct immunofluorescence testing of the haired skin, footpad, and nasal planum of all normal and 9 of the 10 whv ... | 1991 | 2029839 |
| integration of woodchuck hepatitis virus (whv) dna at two chromosomal sites (vk and gag-like) in a hepatocellular carcinoma. | integration of woodchuck hepatitis virus (whv) dna into the liver dna of a woodchuck infected by the virus was investigated. clonal viral integration was not detected three months before the appearance of four hepatocellular carcinomas (hcc). integration of the viral dna was detected in all four hccs, of which one was chosen to determine the structure of the viral integration completely in a single tumor. the integration occurred in two sites. one part contains the viral dna from the middle of t ... | 1991 | 2055466 |
| hepatic lesions in woodchucks (marmota monax) seronegative for woodchuck hepatitis virus. | livers from 128 captive woodchucks (marmota monax) that were negative for serological markers of woodchuck hepatitis virus (whv) were examined grossly and histologically. livers from 19 additional seronegative woodchucks were examined only grossly. the most common finding (61% of histological specimens) was mononuclear cells in portal areas. moderate to severe portal infiltrates in association with similar scattered mononuclear cell aggregates and extramedullary hematopoiesis, were present in wo ... | 1991 | 2067050 |
| autoantibody pattern in a woodchuck model of hepatitis b. | spectrum, dynamics, and immunoglobulin class of the non-organ specific autoantibodies were investigated in 646 sequential sera from 18 woodchucks with experimental woodchuck hepatitis virus (whv) infection and in 8 naturally infected chronic carriers of the virus. among examined whv carriers, 8 animals developed hepatocellular carcinoma. the sera were tested by indirect immunofluorescence for autoantibodies against smooth muscle (sma), nuclei (ana), brush border of proximal renal tubuli (abba), ... | 1990 | 2078910 |
| phenotypic patterns of preneoplastic and neoplastic hepatic lesions in woodchucks infected with woodchuck hepatitis virus. | chronic infection of woodchucks with woodchuck hepatitis virus (whv) was associated with the development of hepatitis, foci of altered hepatocytes and hepatocellular adenomas and carcinomas. the cytomorphological and cytochemical analysis permitted the identification of three different types of focal lesions; namely, glycogen-storage foci, mixed-cell foci and intermediate-cell foci, each showing a characteristic pattern. the cells of the glycogen-storage foci had clear to acidophilic cytoplasm, ... | 1990 | 2152341 |
| woodchuck hepatitis virus infection: a model of human hepatic diseases and hepatocellular carcinoma. | | 1990 | 2156308 |
| trans-complementation of the c gene of human and the p gene of woodchuck hepadnaviruses. | a 5 bp insertion was introduced into the bsteii site at nucleotide 2815 in dna of hepatitis b virus (hbv) and a mutant hbv genome was produced, which coded for envelope and core proteins, but not for dna polymerase, due to a frameshift. cultured hepatoma cells (hepg2) were simultaneously transfected with a plasmid harbouring a tandem dimer of the mutant hbv dna and another plasmid harbouring a tandem dimer of dna of woodchuck hepatitis virus or duck hepatitis b virus. the replication of mutant h ... | 1990 | 2157804 |
| hepatitis b virus and primary hepatocellular carcinoma: treatment of hbv carriers with phyllanthus amarus. | a viricide capable of eliminating hepatitis b virus (hbv) from chronic carriers should, theoretically, decrease the risk of primary hepatocellular carcinoma. extracts of phyllanthus amarus have been shown to inhibit the dna polymerase of hbv and woodchuck hepatitis virus (whv) in vitro. three of four recently infected whv carriers treated i.p. with p. amarus extract lost whv, animals infected for greater than or equal to 3 months showed a decrease in virus levels. preliminary results in human ca ... | 1990 | 2158192 |
| clonal origin of mammalian hepatitis b virus-related hepatocellular carcinoma. | the clonal origins of 20 multifocal hepatocellular carcinomas (hccs) in four woodchucks were analyzed by the southern blot hybridization technique. the woodchucks were divided into two groups according to the morphological classification of multifocal tumors: 1) three woodchucks had multifocal tumors that were widely separated and similar in size, which suggests a multiclonal origin of the tumors; and 2) one woodchuck had ten small multifocal tumors surrounding two large main tumors, which indic ... | 1990 | 2164561 |
| integration of hepatitis virus dna near c-myc in woodchuck hepatocellular carcinoma. | a total of 33 hepatocellular carcinomas, induced in woodchucks by chronic infection with woodchuck hepatitis virus (whv), a virus closely related to the human hepatitis b virus, were analyzed for the state of viral dna, the expression of viral genes and of different cellular proto-oncogenes. low levels of viral replication and presence of integrated viral forms including sequences of the enhancer element, appeared as a general rule in these tumors. enhanced expression of one or more of the nucle ... | 1990 | 2172071 |
| hepadnaviruses, their infections and hepatocellular carcinoma. | ten years ago hepatitis b virus (hbv) was thought to be a unique virus, not included in any known family of viruses. following the discovery of a number of hbv-like viruses that infect birds and mammals, the existence of a new family known as hepadnaviridae has been confirmed. hepadnaviruses are small hepatotropic viruses that have a characteristic partially double stranded genome, exhibit a narrow host range and replicate by reverse transcription. the family currently comprises six viruses of w ... | 1990 | 2178194 |
| frequent activation of n-myc genes by hepadnavirus insertion in woodchuck liver tumours. | the recent finding of c-myc activation by insertion of woodchuck hepatitis virus dna in two independent hepatocellular carcinoma has given support to the hypothesis that integration of hepatitis b viruses into the host genome, observed in most human and woodchuck liver tumours, might contribute to oncogenesis. we report here high frequency of woodchuck hepatitis virus dna integrations in two newly identified n-myc genes: n-myc1, the homologue of known mammalian n-myc genes, and n-myc2, an intron ... | 1990 | 2205804 |
| experimental whv infection of woodchucks: an animal model of hepadnavirus-induced liver cancer. | woodchuck hepatitis virus (whv), a member of the hepadnaviridae, is closely related to hbv in its virus structure, genetic organization and mechanism of replication. natural infection of woodchucks is associated with chronic liver disease and primary hepatocellular carcinoma (hcc). a concerted effort to develop the woodchuck as an experimental animal model of hepadnavirus-induced disease was initiated in 1980. the experimental studies have established the following: (1) chronic whv carriage as a ... | 1990 | 2227264 |
| development of transgenic mice containing woodchuck hepatitis virus dna. | we produced transgenic mice containing woodchuck hepatitis virus dna with tandem repeat structure capable of producing virus and viral antigens. poly(a)+ rnas probably corresponding to pregenome and viral antigens were detected in their liver. these mice have now been healthy for one year. however, there is the possibility of inducing immunologically mediated hepatitis. we anticipate these transgenic mice may present a useful model system for studying the significance of chronic hepatitis in hep ... | 1990 | 2227266 |
| immunization of woodchucks with recombinant hepatitis delta antigen does not protect against hepatitis delta virus infection. | to assess the role of immunization against hepatitis delta antigen in the prevention of hepatitis delta virus infection, woodchuck carriers of woodchuck hepatitis virus were immunized with a 64 amino acid portion of hepatitis delta antigen from its n-terminal region. the protein was expressed in escherichia coli and contained a major immunogenic epitope. a significant anti-hepatitis delta response was observed that did not, however, protect the animals from hepatitis delta virus superinfection. ... | 1990 | 2227808 |
| [woodchuck hepatitis virus and enhancer]. | | 1990 | 2236617 |
| evidence against a requisite role for defective virus in the establishment of persistent hepadnavirus infections. | the factors involved in the establishment of persistent hepadnavirus infection are poorly understood. recent findings demonstrate that the sequence of the genome of hepatitis b virus (hbv) is variable in infected individuals and that, in some cases, virus mutants predominate. our objectives in the present study were to analyze the variability of woodchuck hepatitis virus (whv) genomes in an infected animal and to determine whether sequence heterogeneity played a critical role in the ability of w ... | 1990 | 2251274 |
| different outcomes of chronic hepatitis delta virus infection in woodchucks. | hepatitis delta virus (hdv) superinfection of woodchuck chronic carriers of woodchuck hepatitis virus (whv) results in acute and chronic disease. the different courses of disease mimicked the outcome of human hdv superinfection, making woodchucks valuable models for clinical studies of hdv. ten of 11 woodchuck chronic carriers of whv superinfected with hdv developed acute hdv infection with markers of viral replication in the serum and liver. one animal (dw128) had no serological markers of acut ... | 1990 | 2255230 |
| identification and characterization of the woodchuck hepatitis virus origin of dna replication. | replication of the woodchuck hepatitis virus (whv) genome requires the synthesis of minus-strand dna from an rna template, the pregenome, by reverse transcription. during this reaction, the 5' end of minus-strand dna becomes covalently linked to a protein. the position of the 5' end of minus-strand dna was identified previously, but the initiation site for dna synthesis on pregenomic rna remained ambiguous because of a sequence repetition at the termini of the rna template for reverse transcript ... | 1990 | 2293662 |
| x antigen/antibody markers in hepadnavirus infections. presence and significance of hepadnavirus x gene product(s) in serum. | the finding that x antigen is associated with hepatitis b core antigen particles and that serum hepatitis b e antigen derives from the cleavage of one or more core associated polypeptides raises the question as to whether core associated x antigen could be similarly generated and released into serum. to test this hypothesis, antisera raised to x antigen peptides were used to construct an enzyme-linked solid-phase immunoassay to detect x antigen in sera from patients infected with hepatitis b vir ... | 1990 | 2311861 |
| inhibitory effects of 2'-fluorinated arabinosyl-pyrimidine nucleosides on woodchuck hepatitis virus replication in chronically infected woodchucks. | the treatment of woodchuck hepatitis virus infections with 1-(2'-deoxy-2'-fluoro-beta-d-arabinofuranosyl)-5-iodocytosine (fiac) and 1-(2'-deoxy-2'-fluoro-beta-d-arabinofuranosyl)-5-methyluracil (fmau), given intraperitoneally, caused complete and permanent decrease of serum virus endogenous dna polymerase and viral dna in all treated woodchucks but was associated with severe toxicity. by contrast 1-(2'-deoxy-2'-fluoro-beta-d-arabinofuranosyl)-5-ethyluracil (feau) induced a sustained, although le ... | 1990 | 2334160 |
| monoclonal antibodies raised to purified woodchuck hepatitis virus core antigen particles demonstrate x antigen reactivity. | woodchuck hepatitis core antigen (whcag) particles purified from the liver of chronically infected animals were used for monoclonal antibody production. most of the putative clones demonstrated anti-whc specificity. however, the supernatants from several putative clones bound x antigen sequences from woodchuck hepatitis virus (whv) and hepatitis b virus (hbv). one monoclonal antibody, designated wc9-85 (an igm), specifically bound hepatitis b x antigen (hbxag) residues spanning positions 115-131 ... | 1990 | 2353460 |
| hepadna virus nucleocapsid and surface antigens and the antigen-specific antibodies associated with hepatocyte plasma membranes in experimental woodchuck acute hepatitis. | hepatocyte plasma membranes purified from five woodchucks with distinct serologic and histologic patterns of experimentally induced acute woodchuck hepatitis virus (whv) infection were studied to determine the virus antigens expression and anti-viral specificity of the bound immunoglobulins. whv core, e, and surface antigens (whcag, wheag, and whsag, respectively) were analyzed with the use of immunoblotting technique both in the native form of these membranes and in the membranes treated with h ... | 1990 | 2359258 |
| x antigen/antibody markers in hepadnavirus infections. antibodies to the x gene product(s). | antibodies to the x antigen of hepatitis b virus and woodchuck hepatitis virus were assayed in serial sera from infected individuals and compared with other markers of infection. antibody to the x antigen was found in 11 of 17 (65%) patients and 17 of 40 (42%) woodchucks that were surface-antigen positive. in comparison, this antibody was found in 5 of 14 (36%) patients and in none of 4 woodchucks that were surface-antigen negative. in 5 of 6 patients showing seroconversion from hepatitis b e an ... | 1990 | 2365196 |
| natural history of experimental woodchuck hepatitis virus infection: molecular virologic features of the pancreas, kidney, ovary, and testis. | the kinetic patterns of woodchuck hepatitis virus (whv) infection were monitored in the pancreas, kidneys, ovaries, and testes. groups of woodchucks experimentally infected with a standardized inoculum of whv were sacrificed at different times over a 65-week period beginning in the preacute phase of viral infection and continuing to the period of serologic recovery or the establishment of chronic infections and subsequent hepatocellular carcinoma (b. e. korba, p. j. cote, f. v. wells, b. baldwin ... | 1990 | 2384922 |
| establishment and characterization of a woodchuck hepatocellular carcinoma cell line (wh44ka). | a continuous cell line was established from a hepatocellular carcinoma obtained from a woodchuck that was sero-positive for woodchuck hepatitis virus (whv). the cell line, designated wh44ka, grows as an adhering monolayer with a doubling time of 36 hr in dulbecco's modified eagle's medium supplemented with 10% fetal bovine serum. the cells not only showed epithelial origin on light and electron microscopic examination but also possess biosynthetic markers of the latter, such as albumin and alpha ... | 1988 | 2453497 |
| insulinlike growth factor ii expression and oval cell proliferation associated with hepatocarcinogenesis in woodchuck hepatitis virus carriers. | insulinlike growth factor ii (igf-ii) is a highly mitogenic fetal growth factor suspected of regulating the growth of a wide spectrum of tissues via an autocrine or paracrine mode of action or both. high steady-state levels of igf-ii rna were detected in 45% of hepatocellular carcinomas (hccs) arising from woodchuck livers with persistent woodchuck hepatitis virus (whv) infection. analysis of whv rna in the same hccs revealed that hccs with high levels of igf-ii rna contained low or undetectable ... | 1988 | 2457114 |
| x-region-specific transcript in mammalian hepatitis b virus-infected liver. | in vitro gene expression systems for hepatitis b virus have demonstrated that the virus genome is capable of producing an x-region-specific transcript of approximately 0.7 kilobases (kb). however, this transcript has not been detected in virus-infected cells. we now report the presence of a heterogeneous x-region-specific transcript of approximately 0.65 kb that is found primarily in the nucleus of liver cells infected with the woodchuck hepatitis virus. interestingly, the majority of the transc ... | 1988 | 2459409 |
| hepatocellular carcinoma in woodchuck hepatitis virus-infected woodchucks: presence of viral dna in tumor tissue from chronic carriers and animals serologically recovered from acute infections. | during long-term studies of the natural history of woodchuck hepatitis virus infection, five cases of histologically confirmed, primary hepatocellular carcinoma were observed in a total of 92 woodchucks which had recovered, by analysis of viral serologic markers (whsag-, anti-whc+, anti-whs+), from experimental acute woodchuck hepatitis virus infections 20 to 30 months prior to the detection of hepatocellular carcinoma. no hepatocellular carcinoma was observed in 167 uninfected controls at least ... | 1989 | 2465987 |
| characterization of the incorporation of woodchuck hepatitis virus surface antigen into hepatocyte plasma membrane in woodchuck hepatitis and in the virus-induced hepatocellular carcinoma. | interaction between woodchuck hepatitis virus surface antigen and proteins of hepatocyte plasma membranes were examined in the course of woodchuck hepatitis virus infection. membranes purified from animals with histologically confirmed acute hepatitis, active or persistent chronic hepatitis and the virus-related hepatocellular carcinoma were evaluated for the virus surface antigen contents, treated with agents eluting plasma membrane-bound antigen to test the extent of the antigen-membrane assoc ... | 1989 | 2535620 |
| chromosomal assignment of woodchuck hepatitis virus (whv) dna integration sites in a woodchuck hepatocellular carcinoma-derived cell line (wh257ge10). | the chromosomal sites of woodchuck hepatitis virus (whv) dna integration were identified in a woodchuck hepatocellular carcinoma-derived cell line (wh257ge10) by the in situ hybridization technique using 3h-labelled whv whole genome (whv 2) as a probe. the g-banded chromosome spreads from wh257ge10 were identified and diagrammed schematically according to their band patterns. whv dna was integrated into 2 sites: 33 region of the long arm of chromosome 6 (6q33) and 31 region of the long arm of ch ... | 1989 | 2539331 |
| interaction of fucoidan from pelvetia fastigiata with surface antigens of hepatitis b and woodchuck hepatitis viruses. | a sulfated polysaccharide isolated from pelvetia fastigiata, a marine algae, was found to inhibit in vitro the reaction of the surface antigen of hepatitis b virus (hbsag) or of woodchuck hepatitis virus (whsag) with antibody to hbsag (anti-hbs). the polysaccharide was composed mainly of 1----2 linked l-fucose-4-sulfate with some (less than 10%) 1----3 linkages. the inhibition of the reaction of hbsag with anti-hbs or of whsag with anti-hbs was found to be directly proportional to the molecular ... | 1989 | 2544915 |
| characterization of woodchuck hepatitis virus dna and rna in the hepatocellular carcinomas of woodchucks. | integration and transcription of woodchuck hepatitis virus dna were studied by southern and northern blot analysis in 26 hepatocellular carcinomas and in adjacent nontumor tissue of woodchucks (marmota monax). all liver tissue chronically infected with woodchuck hepatitis virus contained various amounts of episomal and replicative forms of woodchuck hepatitis virus dna: episomal and replicative forms of woodchuck hepatitis virus dna without integration were found in six tumors, episomal and inte ... | 1989 | 2545590 |
| in vitro infection of woodchuck hepatocytes with woodchuck hepatitis virus and ground squirrel hepatitis virus. | primary cultures of woodchuck hepatocytes were demonstrated to be susceptible to in vitro infection by both woodchuck hepatitis virus and ground squirrel hepatitis virus, as evidenced by the appearance of dna species characteristic of hepadnavirus replication. initiation of infection by woodchuck hepatitis virus was blocked by the presence of suramin, polybrene, or dideoxycytidine. viral ccc dna, the putative template for viral rna transcription, was detected at 2 days postinfection. accumulatio ... | 1989 | 2549713 |
| hepatitis b virus and hepatocellular carcinoma--treatment of hbv carriers with phyllanthus amarus. | extracts of phyllanthus amarus inhibit the dna polymerase of hbv and related viruses. woodchuck carriers of woodchuck hepatitis virus (whv) were treated intraperitoneally with p. amarus extract. three of four animals which had been recently infected lost the virus. animals infected for about 3 months or more had a decrease in virus levels. human carriers of hbv were treated orally for 1 month. about 60% of the carriers lost hbv, which did not return during the observation period. fractions conta ... | 1989 | 2559794 |
| hepadnaviruses and hepatocellular carcinoma (hcc). | members of the hepadnavirus family share properties of virion structure, genome structure and replication, epidemiologic behavior, and pathogenic effects. persistent infections with hepatitis b virus (hbv) in man, woodchuck hepatitis virus (whv) in marmota monax, ground squirrel hepatitis virus (gshv) in spermophilus beecheyi, and duck hepatitis b virus (dhbv) in domestic ducks of china are associated with development of hepatocellular carcinoma (hcc). epidemiological evidence implicating hepadn ... | 1989 | 2559799 |
| construction of a plasmid for expression of foreign epitopes as fusion proteins with subunit b of escherichia coli heat-labile enterotoxin. | a novel vector (pfs2.2) for high-level expression of fusion polypeptides with the nontoxic subunit b (lt-b) of escherichia coli heat-labile enterotoxin in escherichia coli and salmonellae is presented. it carries the complete coding sequence of lt-b under lac promoter control and a universal polylinker site for the in-frame insertion of foreign genes at the lt-b gene 3' end. by using this vector, fusion proteins comprising parts of the human or woodchuck hepatitis b virus surface and nucleocapsi ... | 1989 | 2647637 |
| hepadnavirus-induced liver cancer in woodchucks. | woodchuck hepatitis virus (whv), a member of the hepadnaviridae, is closely related to hepatitis b virus (hbv) in its virus structure, genetic organization, and mechanism of replication. as with hbv in man, persistent whv infection is common in natural woodchuck populations and is associated with chronic hepatitis and hepatocellular carcinoma (hcc). in 1980, a program was initiated to develop the woodchuck as an experimental model of hepadnavirus infection and disease. the experimental studies h ... | 1989 | 2695243 |
| molecular analysis of the function of direct repeats and a polypurine tract for plus-strand dna priming in woodchuck hepatitis virus. | the replication of the hepadnavirus dna genome is initiated by reverse transcription of pregenome rna into minus-strand dna followed by plus-strand dna synthesis. the priming of plus-strand dna requires the transfer of an rna primer from pregenome rna to the primer-binding site on minus-strand dna. annealing of the primer to the primer-binding site is facilitated by short direct repeats, dr1 and dr2. to investigate the mechanism of plus-strand primer formation, we have introduced specific mutati ... | 1989 | 2704069 |
| enhanced metabolic activation of chemical hepatocarcinogens in woodchucks infected with hepatitis b virus. | the metabolism of chemical carcinogens was investigated in liver preparations from 28 captive woodchucks (marmota monax). of these, 23 were naturally infected with the woodchuck hepatitis virus (whv), and eight also had primary hepatocellular carcinoma (phc). twenty-nine parameters were investigated in liver subcellular fractions, including cross-reactivity with hbsag, and biochemical parameters, such as gamma-glutamyl transpeptidase, cytochrome p-450 and microsomal monooxygenases (aryl hydrocar ... | 1989 | 2720903 |
| mutation rate of the hepadnavirus genome. | an essential factor for charting the evolution of hepadnaviruses is an estimation of the mutation rate of the virus genome during replication in the host. in order to determine the mutation rate of the hepadnavirus genome under defined experimental conditions, we transfected 10 neonatal woodchucks with an infectious molecular clone of woodchuck hepatitis virus (whv). by 4 months post-transfection, all 10 animals showed serological evidence for whv infection. subsequently, 1 animal became chronic ... | 1989 | 2728351 |
| [breeding and care for wild woodchucks (marmota monax) by indoor and outdoor housing]. | woodchuck (marmota monax) is a very useful animal for studying human diseases such as endocrine, metabolic or cardiovascular diseases. it is regarded especially as the most excellent animal model for human hepatic cell cancer since woodchuck hepatitis virus has various biological characters similar to those of human hepatitis b virus. we have investigated in domestic this wild animals as laboratory experimental animals and succeeded in breeding and rearing in our outdoor facilities. | 1989 | 2744103 |
| protection of woodchucks from infection with woodchuck hepatitis virus by immunization with recombinant core protein. | woodchucks were immunized with recombinant woodchuck hepatitis virus (whv) core antigen (whcag) to investigate whether such immunization protects against whv infection. the c gene was cloned into a puc12 vector and expressed in escherichia coli. core particles purified by sucrose and cscl gradient centrifugation had a buoyant density of 1.37 g/ml which corresponded to the density of whcag particles present in chronically infected liver. two animals immunized with the recombinant antigen develope ... | 1989 | 2769230 |
| host-independent evolution and a genetic classification of the hepadnavirus family based on nucleotide sequences. | an analysis of molecular phylogeny was undertaken to examine whether the evolution of the hepadnavirus family is host-dependent. using the nucleotide sequences of 18 strains, we constructed phylogenetic trees. the trees obtained show that all 12 strains of hepatitis b virus can be classified into four subgroups that are not compatible with conventional subtypes. we estimated the rate of synonymous (silent) substitution for hepatitis b virus to be 4.57 x 10(-5) per site per year. applying this ra ... | 1989 | 2780562 |
| transcriptional activation of homologous and heterologous genes by the hepatitis b virus x gene product in cells permissive for viral replication. | the potential of the hepadnavirus x gene product to activate gene expression in trans was tested through a series of cotransfections of x expression vectors with a variety of potential targets for transactivation. the x gene products from human hepatitis b virus (hbv), woodchuck hepatitis virus, and ground squirrel hepatitis virus are all equally active in augmenting the expression of a wide array of target promoters in both permissive and nonpermissive cells. using the hbv genome itself as the ... | 1989 | 2788226 |
| in vitro production of infectious woodchuck hepatitis virus by lipopolysaccharide-stimulated peripheral blood lymphocytes. | peripheral blood lymphocytes (pbls) from a wild-caught woodchuck (wc192) chronically infected with woodchuck hepatitis virus (whv) carried low levels of nonreplicating whv genomes. in a previous study, these whv genomes were induced to replicate and intact whv particles were released when these pbls were cultured in the presence of the generalized mitogen, lipopolysaccharide (lps). to determine whether the culture-derived whv particles were infectious, adult woodchucks were inoculated with cell- ... | 1989 | 2794556 |
| expression of infectious woodchuck hepatitis virus in murine and avian fibroblasts. | the liver is the primary site for replication of the hepadnavirus genome. we asked whether the posttranscriptional phase of the viral replication cycle would depend on hepatocyte-specific functions. for this purpose, we assayed a previously constructed chimera between sequences of the cytomegalovirus immediate-early promoter-enhancer region and woodchuck hepatitis virus (whv) (c. seeger and j. maragos, j. virol. 63:1907-1915, 1989) for its ability to direct the synthesis of infectious whv in hep ... | 1989 | 2795716 |
| characterization of a herpesvirus isolated from woodchuck hepatocytes. | a dna virus with the characteristics of a herpesvirus has been isolated from woodchuck hepatocytes cultured in vitro. we refer to this virus as herpesvirus of marmots (hvm). electron microscopy of thin sections of hvm-infected cells showed nucleocapsids with a hexagonal outline and a diameter of 80 nm. enveloped virions were seen in cytoplasmic vacuoles and outside the cell. negatively stained virus particles purified from cell supernatants were enveloped with the characteristic appearance of he ... | 1988 | 2839596 |
| establishment and characterization of a diethylnitrosamine-initiated woodchuck hepatocyte cell line. | woodchucks free from woodchuck hepatitis virus were treated with diethylnitrosamine in vivo for 2 months, and then hepatocytes obtained by enzymatic perfusion were cultured with the hepatopromoter phenobarbital. this in vivo-in vitro procedure gave rise to proliferating epithelial cell foci, from one of which the presently described hepatocyte cell line (wlc-3) was established and characterized. wlc-3 cells possess morphological and biochemical features of differentiated hepatocytes, including g ... | 1987 | 2888713 |
| enzyme-altered liver cell foci in woodchucks infected with woodchuck hepatitis virus. | the histochemical characteristics of liver cell foci in woodchucks were investigated. the foci appeared to be distributed throughout the liver and were observed only in the woodchuck hepatitis virus (whv)-positive animals, including all 19 woodchucks with hepatocellular carcinoma(hcc), and 7 without hcc. no foci appeared in 11 whv-negative animals. histochemical studies revealed that liver cell foci and carcinoma cells were characterized by positive gamma-glutamyl transpeptidase (ggt) enzymatic ... | 1988 | 2898465 |
| natural history of woodchuck hepatitis virus infections during the course of experimental viral infection: molecular virologic features of the liver and lymphoid tissues. | in this study, the kinetic patterns of woodchuck hepatitis virus (whv) infection were monitored in the liver and the five primary components of the lymphoid system (peripheral blood lymphocytes, lymph nodes, bone marrow, spleen, and thymus). groups of woodchucks experimentally infected with a standardized inoculum of whv were sacrificed at different times over a 65-week period beginning in the preacute phase of viral infection and continuing to the period of serologic recovery or the establishme ... | 1989 | 2915383 |
| extrahepatic replication of woodchuck hepatitis virus in chronic infection. | we describe studies of woodchuck hepatitis virus nucleic acids in liver and other tissues of chronically infected woodchucks, using southern and northern blot hybridization techniques. single-stranded and covalently closed circular replicative dna molecules were distinguished from partly double-stranded virus genomes. in most animals the liver contained more virus than any other organ, but all extrahepatic organs studied (spleen, thymus, pancreas, and kidney) contained viral dna and significant ... | 1989 | 2922930 |
| hepatitis delta virus (hdv) and woodchuck hepatitis virus (whv) nucleic acids in tissues of hdv-infected chronic whv carrier woodchucks. | the molecular forms of genomic and antigenomic hepatitis delta virus (hdv) rna and of woodchuck hepatitis virus (whv) dna and whv rna were studied in nonneoplastic liver (nl) tissues, hepatocellular carcinoma (hcc) tissues, and several extrahepatic tissues of chronic whv carrier woodchucks acutely (two animals) and chronically (six animals) superinfected with hdv. hdv was shown to replicate in all nl and hcc tissues but not in any of the extrahepatic tissues analyzed, which included spleen, peri ... | 1989 | 2926865 |
| complete nucleotide sequence of a molecular clone of woodchuck hepatitis virus that is infectious in the natural host. | woodchuck hepatitis virus (whv) dna was cloned from viral particles obtained from the serum of a woodchuck with a naturally acquired infection. the complete nucleotide sequence of the virus genome was determined and found to be 3323 base pairs long. transfection experiments demonstrated that the recombinant whv dna was infectious in each of 18 woodchucks tested and established a chronic carrier state in 1 of 13 neonates and 3 of 5 adult animals. whv dna from serum particles from the chronically ... | 1989 | 2928306 |
| chronic hepatitis and hepatocellular carcinoma associated with persistent woodchuck hepatitis virus infection. | the livers of 16 woodchucks with naturally acquired chronic infection with woodchuck hepatitis virus were examined both grossly and histologically in 14 biopsy specimens and seven necropsy specimens. fifteen woodchucks had lesions characteristic of chronic hepatitis; ten of these had chronic active hepatitis, four had chronic persistent hepatitis, and one had cirrhosis with nodular regeneration. in one woodchuck there was massive hepatic necrosis attributed to infection with an unclassified prot ... | 1985 | 2994274 |
| scintigraphic diagnosis of primary hepatocellular carcinoma in the woodchuck (marmota monax). | hepatic imaging with 99mtc-sulfur colloid was used to diagnose primary hepatocellular carcinoma (phc) in woodchucks infected with woodchuck hepatitis virus (whv). based on imaging results, 6 of 12 whv-infected woodchucks had space-occupying hepatic lesions, and all 6 had phc. of the remaining woodchucks, 2 did not have phc, 2 had discrete tumors (less than 1 cm diameter), 1 had miliary small tumors, and 1 had tumors located near the great vessels. hepatic imaging was a valuable technique for dia ... | 1986 | 3008602 |
| stable integration of woodchuck hepatitis virus dna in transplanted tumors and established tissue culture cells derived from a woodchuck primary hepatocellular carcinoma. | the fate of integrated woodchuck hepatitis viral (whv) dna was systematically investigated in dna samples from primary hepatocellular carcinoma (hcc) of woodchucks, solid tumors transplanted in athymic mice derived from a primary hcc of woodchuck, and an established cell line of tissue culture originating from the transplanted tumor. in four of five woodchuck primary hccs, whv dna integration was demonstrated in addition to various amounts of extrachromosomal replicative intermediate whv dna. th ... | 1986 | 3011252 |
| hepatocellular carcinoma in ground squirrels persistently infected with ground squirrel hepatitis virus. | although persistent infection with hepatitis b virus and woodchuck hepatitis virus has been associated with development of hepatocellular carcinoma in the host, little has been known of such an association with ground squirrel hepatitis virus (gshv), which is closely related to the woodchuck virus. colonies of gshv-infected and -uninfected beechey ground squirrels were observed for tumors for a period of 5 years. tumors developed in seven squirrels after a minimum of 2.4 years of observation per ... | 1986 | 3012572 |
| rearrangement and enhanced expression of c-myc in hepatocellular carcinoma of hepatitis virus infected woodchucks. | hepatocellularcarcinoma (hcc) that occur in woodchucks chronically infected with woodchuck hepatitis virus (whv) were screened for activation of cellular oncogenes. enhanced expression and allelic alterations of the c-myc oncogene were found in three hcc out of nine. variations in the size of the c-myc transcripts, ranging from 2.0 kilobases (kb) to 5.6 kb, as well as in the level of c-myc gene expression, 5-50-fold higher than in adjacent liver tissues, were observed among the three hcc. rearra ... | 1986 | 3024010 |
| [hbv and hepatocellular carcinoma]. | significant research evidence has demonstrated an association between persistent infection with hepatitis b virus (hbv) and the generation of hepatocellular carcinoma (hcc). these findings are based on epidemiologic studies, molecular studies and studies of hbv like viruses. epidemiologically, the geographic correlation between hbv infection and hcc, serum hbsag in patients with hcc, familial clustering of hcc, prospective studies, and pathological studies are discussed. molecular studies of hbv ... | 1987 | 3030195 |
| in vitro recombinants of ground squirrel and woodchuck hepatitis viral dnas produce infectious virus in squirrels. | hepatitis b viruses of humans, woodchucks, ground squirrels, and ducks are similar biochemically but differ with respect to host range and pathogenicity. to pursue the genetic basis of these properties in the absence of a cell culture system for virus growth, we exploited the demonstrated infectivity of cloned hepatitis b virus dna in whole animals. we constructed several recombinant molecules in vitro between cloned infectious genomes of woodchuck hepatitis virus (whv) and ground squirrel hepat ... | 1987 | 3041044 |
| activation of c-myc by woodchuck hepatitis virus insertion in hepatocellular carcinoma. | two hepatocellular carcinomas, induced in woodchucks chronically infected with woodchuck hepatitis virus, were characterized for viral integration near c-myc and alterations of c-myc expression. in one tumor, viral integration within the untranslated region of c-myc exon 3 resulted in overexpression of a long c-myc viral cotranscript. in the second tumor, a single insertion of highly rearranged viral sequences 600 bp upstream of c-myc exon 1 was associated with increased levels of normal c-myc m ... | 1988 | 3180223 |
| propagation of woodchuck hepatitis delta virus in primary woodchuck hepatocytes. | monolayer cell cultures of primary woodchuck hepatocytes, prepared by perfusing the liver in situ with collagenase type i, yielded hepatocytes with a viability of greater than 90% which could be held in culture for up to 3 months. cultures of primary woodchuck hepatocytes were infected one day after plating with hepatitis delta virus (hdv) which had been passaged five times in woodchucks and was therefore identified as woodchuck hepatitis delta virus (whdv). replication of whdv was demonstrated ... | 1988 | 3201748 |