Publications
| Title | Abstract | Year(sorted ascending) Filter | PMID Filter |
|---|
| rearrangement of the surface antigen gene of hepatitis b virus integrated in the human hepatoma cell lines. | the rearrangement of integrated hbv dna sequences in three different hepatoma cell lines, huh-1, huh-2, kg-55-t from japanese patients, were studied by blot hybridization using whole hbv genome or a hbsag or hbcag dna as a probe. the characteristic existence of multiple integration sites of hbv dna sequences in each hindiii-restricted hepatoma cell dna was revealed by the hbv genome probe. detection of the isolated hbsag gene in the hindiii fragment indicates that the integration of hbv dna was ... | 1983 | 6310497 |
| human hepatitis b vaccine from recombinant yeast. | the worldwide importance of human hepatitis b virus infection and the toll it takes in chronic liver disease, cirrhosis and hepatocarcinoma, make it imperative that a vaccine be developed for worldwide application. human hepatitis b vaccines are presently prepared using hepatitis b surface antigen (hbsag) that is purified from the plasma of human carriers of hepatitis b virus infection. the preparation of hepatitis b vaccine from a human source is restricted by the available supply of infected h ... | 1984 | 6318124 |
| woodchuck hepatitis virus: experimental infection and natural occurrence. | 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 o ... | 1984 | 6383996 |
| core antigen and antibody in woodchucks after infection with woodchuck hepatitis virus. | the woodchuck hepatitis virus is a naturally occurring hepatitis b-like virus that infects the eastern woodchuck. direct immunofluorescence staining for woodchuck hepatitis virus core antigen in liver biopsies demonstrated the presence of this antigen in 14 of 17 chronically infected woodchucks, and in 8 of 10 woodchucks undergoing acute infections. fluorescent localization of woodchuck hepatitis virus core antigen was typically cytoplasmic, and this was confirmed further by electron microscopy. ... | 1984 | 6384556 |
| [spontaneous and experimental infection of alpine marmots (marmota marmota) by the north american woodchuck hepatitis virus (marmota monax). initial results]. | summer's discovery in 1978 of a dna virus, very close to human hepatitis b virus in a woodchuck population in the u.s.a. (pennsylvania) was a confirmation of the first description made by snyder at penrose research laboratory (philadelphia). it was the first animal model of human b hepatitis infection. the comparative study of morphological, ecological and ethological characteristics of the marmot (marmota marmota) and the woodchuck (marmota monax) enables an easy distinction between these two s ... | 1984 | 6532649 |
| inhibition of human and woodchuck hepatitis virus dna polymerase by the triphosphates of acyclovir, 1-(2'-deoxy-2'-fluoro-beta-d-arabinofuranosyl)-5-iodocytosine and e-5-(2-bromovinyl)-2'-deoxyuridine. | the triphosphates of acyclovir (acv), 1-(2'-deoxy-2'-fluoro-beta-d-arabinofuranosyl)-5-iodocytosine (fiac) and e-5-(2-bromovinyl)-2'-deoxyuridine (bvdu) have been examined for their inhibitory effects on the endogenous dna polymerase reactions of human hepatitis b virus (hbv) and woodchuck hepatitis virus (whv). all three triphosphates (acvtp, fiactp and bvdutp) inhibited the hbv and whv dna polymerases by competing with the corresponding natural substrates. fiactp was the most potent inhibitor ... | 1984 | 6541455 |
| liver disease associated with duck hepatitis b virus infection of domestic ducks. | the liver disease associated with duck hepatitis b viremia was investigated in naturally infected ducks from chi-tung county in china and in both naturally and experimentally infected ducks from the united states. liver and serum specimens of adult chinese ducks were examined for duck hepatitis b virus (dhbv) dna by dot and gel blot hybridization. dhbv was found in serum and (in episomal form only) in livers of 6 of 11 birds exhibiting various degrees of chronic hepatitis. in 1 bird with hepatoc ... | 1984 | 6583686 |
| transmission of the hepatitis b virus-associated delta agent to the eastern woodchuck. | delta agent of human origin was inoculated into four woodchucks chronically infected with woodchuck hepatitis virus (whv). the animals developed delta infections with serologic patterns similar to those previously observed in human and chimpanzee infections. delta antigen was detected transiently in serum and liver and was followed by seroconversion to anti-delta antibody. analogous to the chimpanzee model of delta infection, serum and hepatocyte markers of whv were suppressed in the woodchuck d ... | 1984 | 6585793 |
| predicted secondary structure similarity in the absence of primary amino acid sequence homology: hepatitis b virus open reading frames. | proteins that are related evolutionarily may have diverged at the level of primary amino acid sequence while maintaining similar secondary structures. computer analysis has been used to compare the open reading frames of the hepatitis b virus to those of the woodchuck hepatitis virus at the level of amino acid sequence, and to predict the relative hydrophilic character and the secondary structure of putative polypeptides. similarity is seen at the levels of relative hydrophilicity and secondary ... | 1984 | 6585835 |
| nucleotide sequence of an infectious molecularly cloned genome of ground squirrel hepatitis virus. | 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 lo ... | 1984 | 6086950 |
| synthesis in animal cells of hepatitis b surface antigen particles carrying a receptor for polymerized human serum albumin. | a recombinant plasmid (psvs dhfr) encoding the pre-s region and the s gene of human hepatitis b virus (hbv) and murine dihydrofolate reductase (dhfr) cdna has been used for the transfection of chinese hamster ovary (cho) dhfr- cells. selection of clones resistant to methotrexate has permitted amplification of hbv sequences and an increase in production of hepatitis b surface antigen (hbsag). hbv-specific transcripts have been characterized. the hbsag 22-nm particles contain a receptor for polyme ... | 1984 | 6096851 |
| a transformed vero cell line stably producing the hepatitis b virus surface antigen. | we have constructed plasmids in which transcription of the surface antigen gene of the human hepatitis b virus (hbsag) is under the control of the sv40 early promoter. these plasmids have been used to analyze the expression of the hbsag gene, both in mouse cells and in african green monkey kidney (vero) cells. we have established a vero cell line continuously expressing hbsag that is indistinguishable from authentic 22 nm hbsag particles. post-transcriptional modification of hbsag mrna also appe ... | 1984 | 6098537 |
| liver carcinogenesis in tropical africa. | the geographical pathology of hepatocellular carcinoma (hcc) was essentially anecdotal until systematic cancer registration was introduced, but it is now clear that sub-saharan africa is a high-incidence area. the disease is multifactorial in etiology, the possible etiological agents including hepatitis b virus and a number of chemical carcinogens, among which the most important appear to be the aflatoxins and n-nitroso compounds. medicinal plants and herbal teas used in the tropics also contain ... | 1984 | 6100283 |
| sarcoma growth in 15i5 x 7(2) chickens infected with avian sarcoma viruses of subgroup b or g. | a comparative study was made of sarcoma growth in 15i5 x 7(2) chickens infected in the wing web at 4 weeks of age with strains of subgroup b or g avian sarcoma viruses. infection with sarcoma viruses of either subgroup b or g resulted in the formation of progressive wing web sarcomas at the site of inoculation. the survival times of the subgroup g virus-infected chickens were generally at least twice as great as the survival times of the subgroup b virus-infected chickens, which averaged 6-9 wee ... | 1984 | 6100579 |
| nucleotide sequence of a cloned duck hepatitis b virus genome: comparison with woodchuck and human hepatitis b virus sequences. | the nucleotide sequence of an ecori duck hepatitis b virus (dhbv) clone was elucidated by using the maxam and gilbert method. this sequence, which is 3,021 nucleotides long, was compared with the two previously analyzed hepatitis b-like viruses (human and woodchuck). from this comparison, it was shown that dhbv is derived from an ancestor common to the two others but has a slightly different genomic organization. there was no intergenic region between genes 5 and 8, which were fused into a singl ... | 1984 | 6699938 |
| combined interferon-alpha 2, rimantadine hydrochloride, and ribavirin inhibition of influenza virus replication in vitro. | recombinant dna-produced human interferon-alpha 2 inhibited the replication of influenza a and b viruses in primary rhesus monkey kidney cells (rmk). human interferon-alpha 2 interacted additively or synergistically with rimantadine hydrochloride or ribavirin in reducing the yield of clinical isolates of either h3n2 or h1n1 subtype influenza a viruses. the combination of human interferon-alpha 2 and ribavirin also inhibited the replication of an influenza b virus to a greater extent than either ... | 1984 | 6703684 |
| transmission of duck hepatitis b virus from chinese carrier ducks to japanese ducklings: a study of viral dna in serum and tissue. | human hepatitis b-like viruses have been found in several animal species, including chinese ducks. sera from chinese carrier ducks which were positive for duck hepatitis b virus (dhbv) were inoculated in 33 japanese one-day-old ducklings. the same sera were inoculated in four 3-week-old ducklings, and three 3-month-old ducks. ten uninoculated ducklings served as controls. hepatitis b e-antigen positive human sera and dna polymerase-positive woodchuck sera were also inoculated into ducklings. dhb ... | 1984 | 6745848 |
| comparison of properties of woodchuck hepatitis virus and human hepatitis b virus endogenous dna polymerases. | 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 arabino ... | 1984 | 6231885 |
| liver orcein stain and viral dna in duck hepatitis b virus infection in chinese ducks and experimentally infected japanese ducklings. | liver sections were stained with orcein, and duck hepatitis b virus was identified in sera and livers by the hybridization technique in 106 ducks (44 chinese ducks, 15 japanese ducks and 47 japanese ducklings). orcein-positive hepatocytes were found in 18 of 38 (47%) duck hepatitis b virus dna seropositive ducks, and only in 3 of 68 (4%) seronegative ducks. the three ducks were all from a heavily infected flock in southern china. serial analyses of viral dna by southern blot and spot hybridizati ... | 1984 | 6209199 |
| nucleotide sequence of a cloned woodchuck hepatitis virus genome: evolutional relationship between hepadnaviruses. | we have determined the complete nucleotide sequence of a cloned dna of woodchuck hepatitis virus (whv), the most oncogenic virus among hepadnaviruses. the genome, designated whv2, is 3,320 base pairs long and contains four major open reading frames (orfs) coded on the same strand of nucleotide sequence as in the human hepatitis b virus (hbv) genome. comparison of the nucleotide sequence and amino acid sequences deduced from it among the genomes of various hepadnaviruses demonstrates that each pr ... | 1985 | 3855246 |
| duck hepatitis b virus dna in liver and serum of chinese ducks: integration of viral dna in a hepatocellular carcinoma. | the presence of duck hepatitis b virus (dhbv) dna in liver and serum and its state (integrated vs. free) were studied in 23 ducks from chi-tung county in china by spot hybridization and southern blot hybridization, respectively. in 16 of 23 (70%), dhbv dna was detected in serum and/or in liver tissue. these infected ducks showed a variety of pathological changes including advanced chronic disease in the liver. in contrast, none of the virus-negative ducks had advanced hepatic changes. one dhbv d ... | 1985 | 3860852 |
| detection of an igm antiidiotype directed against anti-hbs in hepatitis b patients. | an igm-specific anti-[anti-hbs] antibody was detected by radioimmunoassay using anti-igm-coated beads and 125i-labeled anti-hbs. this antiidiotype was found only in the sera of hepatitis b virus-infected patients, both acute and chronic. however, not all hbsag-positive patients exhibited this reaction, and activity was correlated with the presence of hbeag. approximately 93% of sera that contained antiidiotype activity also contained hbeag. conversely, 70% of the sera positive for hbeag reacted ... | 1985 | 3875543 |
| the hbv hbx gene expressed in e. coli is recognised by sera from hepatitis patients. | we have cloned the x gene (hbx) and the hbc antigen (hbc ag) gene of human hepatitis b virus (hbv) in escherichia coli as fusion products with beta-galactosidase. both hbv genes are expressed in e. coli strain csr 603. expression is detected by u.v. irradiation of the bacteria, metabolic labelling and electrophoresis of the labelled extracts on sds-polyacrylamide gels. the hbc ag protein produced in bacteria can be recognised by anti-hbc sera and peptides derived from the protein are also recogn ... | 1985 | 3891326 |
| establishment of a cell line from a woodchuck hepatocellular carcinoma. | a new cell line derived from a woodchuck hepatocellular carcinoma serially transplanted in athymic nude mice has been established and named wh257ge10. the original tumor in the nude mouse system produces woodchuck hepatitis surface antigen and albumin. in addition, woodchuck hepatitis virus dna is integrated into cellular dna. adaptation of the cells to the in vitro culture condition was completed after 15 months with the doubling time of 40 hr. the morphologic features of the cell by light micr ... | 1985 | 3905560 |
| neuraminic acid is involved in the binding of influenza c virus to erythrocytes. | neuraminidases of both viral and bacterial origin have been reported to be unable to destroy the cellular receptor for influenza c virus on chicken erythrocytes, in contrast to the receptors for influenza a and b virus. however, under appropriate conditions neuraminidases from both vibrio cholerae and clostridium perfringens were able (i) to make chicken red blood cells resistant against agglutination by influenza c virus and (ii) to reduce the hemagglutination-inhibiting activity of rat serum. ... | 1985 | 3976175 |
| radioimmunoassay and characterization of woodchuck hepatitis virus core antigen and antibody. | solid-phase radioimmunoassays for woodchuck hepatitis virus core antigen (whcag) and antibody (anti-whc) were developed. whcag in woodchuck liver homogenates was characterized by ultracentrifugation in cscl gradients; both heavy (1.35 g/cm3) and light (1.31 g/cm3) cores were obtained from the liver of an animal during acute whv infection, which is consistent with observations in hepatitis b virus infection in man. endpoint titers of anti-whc were higher in chronic whv carriers than in animals re ... | 1985 | 4036315 |
| subacute nonsuppurative hepatitis associated with hepatitis b virus infection in two cynomolgus monkeys. | subacute, nonsuppurative hepatitis was diagnosed in a cynomolgus monkey (macaca fascicularis) based on histopathologic examination of a liver biopsy specimen. clinical signs of illness included anorexia, lethargy and hepatomegaly. abnormal laboratory findings included elevations of serum liver enzymes, bilirubin and a monocytosis. circulating antibody (anti-hbs) against hepatitis b surface antigen (hbsag) was present in serum and antigens reactive with anti-hbsag antiserum were found in the live ... | 1985 | 4046551 |
| [circulation of the influenza virus on poultry-raising farms]. | the results of examinations for immunity to influenza in chickens and the personnel handling them at the permanently observed farm are presented. antibodies mainly to the same antigenic variants of human influenza viruses were found in chicken and human blood sera. alongside with antihemagglutinins to influenza a (h3n2) virus strains, chicken in 1983-1984 were found to have antibodies to influenza b virus epidemically important in those years. thus, in poultry farms human influenza viruses are i ... | 1985 | 4049842 |
| alterations in the hemagglutinin associated with adaptation of influenza b virus to growth in eggs. | in 1943 burnet reported on changes in the hemagglutinating properties of human influenza virus which occurred during adaptation of the virus to growth in chicken eggs. only recently has direct evidence been presented that these changes affect the antigenic properties of the virus. schild et al. (g. c. schild, j. s. oxford, j. c. dejong, and r. g. webster (1983), nature (london) 303, 706-709) demonstrated that egg adaptation of influenza b virus selects variants which are antigenically distinct f ... | 1985 | 4060580 |
| protection of chimpanzees from type b hepatitis by immunization with woodchuck hepatitis virus surface antigen. | two chimpanzees immunized with woodchuck hepatitis virus (whv) surface antigen (whsag) developed antibodies cross-reactive with hepatitis b virus (hbv) surface antigen (hbsag). after challenge with hbv, one animal was completely protected and the other experienced a subclinical infection, without evidence of liver disease. three woodchucks immunized with hbsag developed antibodies to hbsag which did not cross-react with whsag. after challenge with whv, all three woodchucks developed typical acut ... | 1986 | 3783820 |
| failure to detect polyalbumin-binding sites on the woodchuck hepatitis virus surface antigen: implications for the pathogenesis of hepatitis b virus in humans. | binding sites for polymerized albumin on hepatitis b virus components were reported in human hepatitis b virus chronic carriers predominantly with active viral replication (hb e antigen positive). the presence of comparable albumin-binding sites in the woodchuck hepatitis virus (whv) model was examined on whv components obtained from woodchucks with active viral replication (dna polymerase positive). binding sites for polymerized woodchuck serum albumin were not detected on the intact whv virion ... | 1986 | 3783821 |
| evidence for the presence of duck hepatitis b virus in wild migrating ducks. | a virus closely related to duck hepatitis b virus (dhbv) was isolated from serum and liver samples of wild migratory ducks (mallards) caught in two separate wildlife reserve parks in france. in the first one (dombes region) 12% of wild mallards were positive for dhbv, and in the second (river somme) 3% of mallards were found positive. the dhbv isolated from the serum of wild mallards was also associated with an endogenous dna polymerase activity capable in vitro of completing a partially double- ... | 1986 | 3005480 |
| herpes simplex virus complement fixing antibody and herpes b virus serum neutralizing antibody in sera of wild and laboratory-bred cynomolgus monkeys. | the result of the complement fixation (cf) test for the antibody to herpes simplex virus (hsv) in sera of the cynomolgus monkeys was compared with that of the neutralization test (ns) for the antibody to herpes b virus (hbv) in the same sera. fifty-seven (74%) of 77 wild-originated monkeys were positive for hsv-cf, while 65 (84%) of the 77 animals were positive for hbv-sn. all of the 57 cf positive cases were also positive for hbv-sn. on the other hand, 30 (75%) of 40 laboratory-bred monkeys had ... | 1986 | 3011466 |
| 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 |
| a recombinant chinese hamster ovary cell line containing a 300-fold amplified tetramer of the hepatitis b genome together with a double selection marker expresses high levels of viral protein. | a new series of double-selection plasmids containing recombinant genes expressing the neomycin phosphotransferase (neo) of transposon tn5 and mouse dihydrofolate reductase (dhfr) in mammalian cells is described. activity of the recombinant dhfr gene varied more than 50-fold, depending on the location of the simian virus 40 72 base-pair repeat or enhancer, which is part of the promoter of the neo unit. a neo-dhfr module with the enhancer located at the 3' end of the dhfr gene was inserted into a ... | 1986 | 3023626 |
| hepadnavirus infection of peripheral blood lymphocytes in vivo: woodchuck and chimpanzee models of viral hepatitis. | the peripheral blood lymphocytes (pbl) of five hepatitis b virus (hbv)-infected chimpanzees and 17 woodchuck hepatitis virus (whv)-infected woodchucks were examined for the presence of viral dna and rna. hbv dna was detected in the pbl of three of three chronically infected chimpanzees but in neither of two animals with acute hbv infection. whv dna was found in the pbl of 11 of 13 chronically infected woodchucks and in the pbl and bone marrow of 1 of 4 woodchucks with antibody to whv surface ant ... | 1986 | 3485201 |
| intracellular assembly and packaging of hepatitis b surface antigen particles occur in the endoplasmic reticulum. | hepatitis b surface antigen (hbsag) particles are secreted by chinese hamster ovary cells that are stably transfected with the s gene of hepatitis b virus. the assembly of hbsag into cylindrical and spherical particles occurred intracellularly within the endoplasmic reticulum. hbsag particles accumulated within large dilated areas of the endoplasmic reticulum and remained within these structures for most of the time prior to secretion from the cells. once the particles were formed, the hbsag pol ... | 1986 | 3517385 |
| products of the "x" gene in hepatitis b and related viruses. | the x region in hepatitis b virus dna potentially encodes a polypeptide 154 amino acids in length. two synthetic peptides spanning residues 100 to 115 (peptide 99) and 115 to 131 (peptide 100) in a hydrophilic domain within the carboxy terminal third of the proposed gene product were made and used to raise peptide antisera in rabbits. such antisera specifically bound to x reactive determinants in liver-derived core antigen particles from humans (hbcag), ducks (dhbcag), ground squirrels (gshcag) ... | 1986 | 2420692 |
| structure and replication of the genome of the hepatitis delta virus. | the hepatitis delta virus can be found in the serum and liver of some hepatitis b virus patients. we now report that the rna genome of serum-derived delta virus is single-stranded and circular. livers of infected chimpanzees or woodchucks contained as many as 300,000 copies of genomic strand rna per average cell, and at least some of this rna had a circular conformation. also present in the livers were rna species complementary to the virion rna. the genomic rna was 5-22 times more abundant than ... | 1986 | 2430299 |
| common evolutionary origin of hepatitis b virus and retroviruses. | hepatitis b virus (hbv), although classified as a double-stranded dna virus, has been shown recently to replicate by reverse transcription of an rna intermediate. also, the putative viral polymerase has been found to share amino acid homology with reverse transcriptase of retroviruses. using computer-assisted dna and protein sequence analyses, we examined the genomes of 13 hepadnavirus isolates (nine human, two duck, one woodchuck, and one ground squirrel) and found that other conserved regions ... | 1986 | 3458214 |
| effects of an extract from phyllanthus niruri on hepatitis b and woodchuck hepatitis viruses: in vitro and in vivo studies. | an aqueous extract of the plant phyllanthus niruri inhibits endogenous dna polymerase of hepatitis b virus and binds to the surface antigen of hepatitis b virus in vitro. the extract also inhibits woodchuck hepatitis virus (whv) dna polymerase and binds to the surface antigen of whv in vitro. the extract, nontoxic to mice, was tested for antiviral activity in woodchucks (marmota monax). in a trial using six long-term whv-carrier woodchucks, five treated animals showed a faster decrease in woodch ... | 1987 | 3467354 |
| hepatocarcinogenicity of the woodchuck hepatitis virus. | during investigations of the evolution of experimental laboratory infections of woodchucks (marmota monax) with the woodchuck hepatitis virus (whv), eight hepatocellular carcinomas (hcc) were observed, six in newborns and two in young adult animals, all within 17-36 months after infection. the absence of an external cocarcinogenic effect in the well-monitored woodchucks indicates the carcinogenicity of whv and suggests the same for the genetically and biologically similar human hepatitis b virus ... | 1987 | 3468514 |
| main properties of duck hepatitis b virus dna polymerase: comparison with the human and woodchuck hepatitis b virus dna polymerases. | the main properties of the duck hepatitis b virus (dhbv) dna polymerase have been studied and compared with those of the human hepatitis b virus (hbv) and of the woodchuck hepatitis virus (whv) dna polymerases. all 3 enzymes are active under high salt conditions in the presence of high magnesium concentration. dhbv dna polymerase was found less sensitive to ethanol and to operate at higher optimal ph than the hbv and whv dna polymerases. like the other two viral endogenous dna polymerases, the d ... | 1987 | 3446017 |
| [detection and identification of host cell antigens in the composition of influenza b virus]. | two heterogeneous antigens, forssman antigen and an antigen similar to human group a antigen, were detected by enzyme-immunoassay in cells of normal chick embryo camn and mdck culture (dog kidney). both these antigens were associated with purified influenza b virus preparations reproduced in these cultures since the variants under study actively reacted with antibodies both to forssman antigen and to human a antigen. serological differences between the variants grown in different cell systems we ... | 1987 | 3300030 |
| the florey lecture, 1986. vaccine prevention of virus-induced human cancers. | carcinogenic viruses have been discovered in numerous animal species over the last 80 years but their role in human cancer has only recently become an important issue. with eb virus involved with endemic burkitt's lymphoma and undifferentiated nasopharyngeal carcinoma, hepatitis b virus with primary liver cancer, papilloma viruses with carcinoma of the cervix, and t-cell leukaemia virus with adult t leukaemia, 20-25% of all human cancer appears to have a virus component in its causation. by anal ... | 1987 | 2884667 |
| [experimental infection of human hepatitis b virus (hbv) in adult tree shrews]. | 1987 | 2962750 | |
| production of hepatitis b virus surface antigen particles by the human hepatoma cell line hugk-14 in a serum-free medium. | the human hepatoma cell line, hugk-14, containing integrated hepatitis b virus (hbv) dnas, produced a large number of 23 nm spherical particles of hbv surface antigen (hbsag) in a serum-free medium. these particles closely resembled the hbsag particles found in the sera of hbv carriers and elicited a high antibody response in guinea pigs. the hugk-14 cells in a serum-free medium would provide a new, economic source of hbv vaccine. | 1987 | 2828295 |
| microbial oncogenesis. | for more than a century, medical investigators have sought to incriminate microorganisms in the cause of cancer. the first scientific evidence of such a relationship came in 1911, with the first successful induction of a tumor using a cell-free extract. since that time, considerable data have accrued linking retroviruses, herpes viruses, the hepatitis b virus, papovaviruses, and adenoviruses to various malignant neoplasms. there is also increasing evidence that certain bacteria and parasites par ... | 1987 | 3541601 |
| maintenance of woodchuck hepatitis virus activity in woodchuck hepatocyte primary culture. | primary cultures of non-proliferating hepatocytes isolated by the two-step collagenase perfusion method from woodchuck naturally infected with hepatitis virus (whv) were used to study whv propagation in vitro. hepatocytes carrying whv dna exhibited a very high level of survival and retained their morphological characteristics for 2 to 3 months. over this time, they were found to produce virus-specific proteins and release viral particles with dna polymerase activity into the medium. using southe ... | 1987 | 3572356 |
| inactivation of influenza b virus by normal guinea-pig serum. | normal guinea-pig serum (gps) lacking detectable antiviral antibody efficiently neutralized the infectivity of influenza b virus grown in chick embryos or mdck cells. the inhibitor was heat-labile and sensitive to trypsin digestion. this beta-like inhibitor required ca2+ and the complement components c1 and c4 for its activity. in contrast, gps did not inactivate influenza a virus. influenza b virus from which the neuraminidase activity of the spikes on the viral envelope had been eliminated by ... | 1987 | 3572357 |
| emerging models in the u.s.a.: swine, woodchucks, and the hairless guinea pig. | swine have been used in biomedical research for many years, but have generally been limited to those locations with personnel familiar with this species and with specially designed facilities and equipment. there is currently a growing trend in the united states for more swine, both miniature and domestic to be used as research models. commercial availability, education through workshops and symposia, and specific research applicability in the areas such as: organ transplantation, cardiovascular ... | 1987 | 3601991 |
| expression of the hepatitis b virus core gene in vitro and in vivo. | the core gene of hepatitis b virus contains two in-phase aug codons which may both be used in the viral life cycle. by in vitro translation of transcripts produced in vitro, we investigated the corresponding core gene products and their counterparts in vivo. depending on the location of the 5' end of the transcripts, two major core gene-derived proteins were obtained. in transcripts with both in-phase augs, only the first one was efficiently used and resulted in synthesis of a 25-kilodalton prot ... | 1987 | 3625840 |
| a cultured cell receptor for the small s protein of hepatitis b virus. | human hepatitis b virus (hbv) has not been passaged in established cell culture systems. to determine whether this inability results from the lack of a receptor, 30 cell lines were examined for their abilities to bind 125i-labeled recombinant hepatitis b virus surface antigen (rhbsag) particles. these particles contained only the small surface (s) protein, which is also found in the envelope of infectious hbv particles. only two cells lines, both derived from african green monkey kidney, were ab ... | 1987 | 3629972 |
| integration of hepatitis b virus: analysis of unoccupied sites. | hepatitis b virus (hbv) sequences integrated in the plc/prf/5 cell line (alexander cells), which was derived from a human primary liver carcinoma, were previously extensively studied. here we describe the analysis of the unoccupied sites of two linearly integrated forms of hbv dna, al-14 and al-26, that were characterized previously. no major cellular dna rearrangements were seen at the integration sites except for small deletions of host sequences: 2 kilobases of dna in al-14 and 17 base pairs ... | 1987 | 3029413 |
| [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 |
| occurrence and ultrastructural localization of duck hepatitis b virus in the liver of ducks after experimental infection. | a sequential study was performed to investigate the occurrence and localization of duck hepatitis b virus in the liver of domestic ducks utilizing the indirect immunoperoxidase method and electron microscopy. seventeen ducklings were injected intravenously with duck hepatitis b virus-positive serum within 24 hr after hatching and were subsequently sacrificed on the 2nd, 3rd, 4th, 5th, 27th and 44th day after injection. nine ducklings were not injected and were used as a negative control. duck he ... | 1987 | 3804203 |
| hepadnaviruses and retroviruses share genome homology and features of replication. | the hepadnavirus family includes hepatitis b virus (hbv), woodchuck hepatitis virus (whv), ground squirrel hepatitis virus (gshv) and duck hepatitis b virus (dhbv). these viruses share unique ultrastructural, molecular and biological features. hbv has great medical importance in many parts of the world. more important numerically than acute hepatitis b in high prevalence geographic regions is the liver disease associated with chronic infection. there appear to be more than 200 million chronicall ... | 1987 | 3804216 |
| molecular aspects of persistent woodchuck hepatitis virus and hepatitis b virus infection and hepatocellular carcinoma. | it seems evident that the development of fully malignant hcc is a multistage process with many variables. one possible mechanism by which many of these variables may interact is as follows. during chronic active hepatitis, viral dna integration occurs randomly and at a low frequency in hepatocytes. integration may be stimulated by the increased rate of hepatocyte cell division resulting from liver necrosis and regeneration during chronic disease. the presence of viral integrations in the cellula ... | 1987 | 3804217 |
| regulation of secretion of the hepatitis b virus major surface antigen by the pres-1 protein. | p24, p30, and p39, the three major surface antigens of the envelope of hepatitis b virus, are co-carboxy-terminal proteins with different amino-terminal extensions. we prompted expression of these proteins in chinese hamster ovary (cho) cells by placing the appropriate coding sequence(s) under the control of the simian virus 40 early promoter. p24 and p30 formed 22-nm particles which were efficiently secreted. in contrast, p39 accumulated in a perinuclear structure, presumably the golgi complex, ... | 1987 | 3806798 |
| infectious influenza a and b virus variants with long carboxyl terminal deletions in the ns1 polypeptides. | an influenza a virus, a/turkey/oregon/71, was shown by protein gel analysis to code for an ns1 protein approximately half the size of those of other influenza a viruses. sequence analysis of the ns gene of this virus revealed a 10 nucleotide deletion resulting in an ns1 protein of only 124 amino acids. this truncated ns1 polypeptide retained its karyophilic pattern as detected by indirect immunofluorescence analysis of virus infected cells. also, a/turkey/oregon/71 virus grew to high titer in em ... | 1987 | 3811235 |
| liver tumors in rodents: extrapolation to man. | man is a poor model for the prediction of agents that are hepatocarcinogenic for laboratory rodents. relatively few agents are known to cause any form of primary liver cancer in man. the most important is hepatitis b virus, for which there is possibly a model in the woodchuck but not one in rats or mice. the only other agents known to cause primary liver cancer in man are certain steroid hormones, vinyl chloride, and thorium dioxide. there are animal models for the first two of these and a reaso ... | 1987 | 3300204 |
| establishment of a new cell line from a woodchuck hepatocellular carcinoma. | a new cell line derived from a woodchuck hepatitis surface antigen-positive woodchuck hepatocellular carcinoma has been established and named t3-hep-w1. this new cell line was established directly from a primary woodchuck hepatocellular carcinoma. adaptation of the cells to the in vitro culture condition was completed after 3 months, with the doubling time of 24 hr. the morphologic features of the cell by light microscopy were of an epithelial type. the modal chromosome number was 100. ornithine ... | 1988 | 3338696 |
| presence of antibodies to the polymerase gene product(s) of hepatitis b and woodchuck hepatitis virus in natural and experimental infections. | antibodies against synthetic peptides derived from the polymerase gene of the hepatitis b virus (hbv) were present in 80% of renal dialysis patients infected with hbv and in woodchucks infected with woodchuck hepatitis virus (whv). polymerase antibody (anti-pol) appeared as the earliest marker of both hbv and whv infections in approximately half of the individuals tested, suggesting that these antibodies were generated following early viral replication in the liver during the incubation period a ... | 1988 | 3351482 |
| dna-binding activity of hepatitis b e antigen polypeptide lacking the protaminelike sequence of nucleocapsid protein of human hepatitis b virus. | the characteristics of binding of hepatitis b core antigen (hbcag) and hepatitis b e antigen (hbeag) polypeptides to hepatitis b virus (hbv) dna were analyzed. hbcag polypeptide from recombinant hbv core particles and hbeag polypeptide from partially purified serum hbeag were prepared and verified to have molecular weights of 21,500 (p21.5) and of 17,000 (p17) and 18,000 (p18), respectively, by immunoblot analysis. by reaction of these proteins on a nitrocellulose membrane with cloned 32p-hbv dn ... | 1988 | 3404582 |
| isolation and characterization of a hepatitis b virus endemic in herons. | a new hepadnavirus (designated heron hepatitis b virus [hhbv]) has been isolated; this virus is endemic in grey herons (ardea cinerea) in germany and closely related to duck hepatitis b virus (dhbv) by morphology of viral particles and size of the genome and of the major viral envelope and core proteins. despite its striking similarities to dhbv, hhbv cannot be transmitted to ducks by infection or by transfection with cloned viral dna. after the viral genome was cloned and sequenced, a comparati ... | 1988 | 3418788 |
| influence of aflatoxin b1 intoxication on duck livers with duck hepatitis b virus infection. | in an attempt to determine the effect of aflatoxin b1 (afb) intoxication on livers with duck hepatitis b virus (dhbv) infection, domestic ducks were given 0.1 mg of afb/kg body weight twice a week for a maximum period of 54 weeks employing various experimental designs. the ducks were infected with dhbv by i.v. inoculation of dhbv-positive sera within 24 h posthatch. the livers were examined histologically, immunohistochemically, and ultrastructurally, and the livers and sera were examined by mol ... | 1988 | 3125965 |
| analysis of the mechanism of influenza b virus inactivation by guinea pig serum. | normal guinea pig serum lacking detectable antiviral antibody inactivated influenza b virus via the classical complement pathway. this virus inactivation appeared to result from the steric hindrance of ha activity by the association with the virus of serum proteins presumed to be complement components. trypsin digestion of the associated proteins fully restored the ha activity but not infectivity. it was found that the virus underwent minor disruption of the envelope and degradation of m1 protei ... | 1988 | 3214275 |
| presence of hbe antibody in glomerular deposits in membranous glomerulonephritis is associated with hepatitis b virus infection. | the specificity of igg on the glomerular capillary wall was investigated in 3 patients with hepatitis b virus associated membranous glomerulonephritis. the immune deposits on the capillary walls were stained by immunofluorescent antibody against hbe antigen and igg. the eluted fluid (0.02 m citrate buffer, ph 3.2) from renal biopsy slices contained significant activity of hbe antibody, but not of hbs and hbc antibodies. after elution, the disappearance of igg on the capillary walls was confirmed ... | 1988 | 3239599 |
| localization of woodchuck hepatitis virus in the liver. | localization of woodchuck hepatitis virus in liver tissue from 10 infected woodchucks was investigated immunohistochemically and ultrastructurally. woodchuck hepatitis virus surface antigen was detected by immunoperoxidase methods in the cytoplasm of hepatocytes with a fine granular and/or inclusion body appearance. woodchuck hepatitis virus surface antigen positive hepatocytes were often found in the peripheral zone of hepatic lobules. in contrast to human hepatitis b core antigen, woodchuck he ... | 1988 | 3276592 |
| the vero cell receptor for the hepatitis b virus small s protein is a sialoglycoprotein. | the vero (african green monkey kidney-derived) cell line is capable of binding recombinant hepatitis b surface antigen (rhbsag) particles containing only the small surface (s) protein of hepatitis b virus (hbv). this binding activity appears to be due to a single major population of receptors (m. e. peeples et al., virology 160, 135-142 (1987]. since infectious hbv particles also contain the small s protein, it is possible that the vero cell receptor might also function as an hbv receptor. the i ... | 1988 | 3281375 |
| integrated structures of duck hepatitis b virus dna in hepatocellular carcinoma. | the structure of integrated viral dna in a hepatocellular carcinoma of a duck from chi-tung county in china was analyzed. three different clones of integrated viral dna, lambda dhs 6-1, lambda dhs 6-2, and lambda dhe 6-2, were obtained from the neoplastic portion of the liver by molecular cloning. one of the three clones, lambda dhs 6-1, showed inverted repetition of integrated viral dna with chromosomal flanking sequences. another clone, lambda dhs 6-2, showed a head-to-head configuration of th ... | 1988 | 2828681 |
| evolution of hepatocellular carcinoma associated with chronic hepatitis b virus infection in alaskan eskimos. | hepatocellular carcinoma (hcc) associated with chronic hepatitis b virus (hbv) infection in yupik eskimos in southwestern alaska, detected in early stages as a result of screening, appears to be more frequently associated with variants of chronic portal inflammation in the noninvolved liver than with fully developed cirrhosis, otherwise common in hbv-associated hcc from other geographic areas. of 38 patients diagnosed with hcc since 1969, adequate tissue was available from both the tumor and non ... | 1988 | 2833872 |
| use of peptides for immunization against foot-and-mouth disease. | a peptide corresponding to the major immunogenic site of the protein vp1 of foot-and-mouth disease virus (fmdv) will elicit a protective neutralizing antibody response in guinea-pigs, cattle and pigs. the response is much greater when the peptide is presented as a linear dimer or tetramer and pigs receiving as little as 40 micrograms peptide have been protected against challenge infection. an even greater response is obtained when the peptide is presented as part of the core protein of hepatitis ... | 1988 | 2838987 |
| relation between hepatocellular carcinoma and persistent hepatitis b infection. | epidemiologic studies indicate a close association between hepatocellular carcinoma (hcc) and chronic hepatitis b virus (hbv) infection. hcc, a most frequent malignancy, is far more common in the far east and africa than in the west and may be the first to be greatly eliminated because of prevention of hbv infection by vaccination. the conceptual integration of epidemiologic observations, morphologic studies of the human precursor stages and investigations of animal infections by hepadna viruses ... | 1988 | 2839217 |
| 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 |
| viral versus chemical hepatocarcinogenesis. | almost all experimental studies on hepatocarcinogenesis have been performed on models induced by chemicals. the human hepatocellular carcinoma (hcc), a highly malignant tumor, particularly frequent in the far east and in africa, is overwhelmingly associated with hepatitis b virus (hbv) infections and only very rarely is it caused by chemicals. this raises the question as to what degree observations on the preferentially studied chemical carcinogenesis apply to human hcc. this question is timely, ... | 1988 | 2842391 |
| 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 |
| influence of env and long terminal repeat sequences on the tissue tropism of avian leukosis viruses. | adsorption and penetration of retroviruses into eucaryotic cells is mediated by retroviral envelope glycoproteins interacting with host receptors. recombinant avian leukosis viruses (alvs) differing only in envelope determinants that interact with host receptors for subgroup a or e alvs have been found to have unexpectedly distinctive patterns of tissue-specific replication. recombinants of both subgroups were highly expressed in bursal lymphocytes as well as in cultured chicken embryo fibroblas ... | 1988 | 2846895 |
| hepatitis delta antigen. antigenic structure and humoral immune response. | hepatitis delta virus (hdv) is a small rna virus that is dependent on helper functions provided by hepatitis b virus. the hepatitis delta ag (hdag) is the only protein known to be made from the viral genome, from an orf with a coding capacity of 214 amino acids. the immunogenic epitopes of hdag and the immune response to it were mapped by the use of synthetic peptides, antipeptide antibodies, and human mab. antipeptide sera covering approximately 60% of the linear sequence reacted with liver-der ... | 1989 | 2479687 |
| [the effect of human gamma globulin on tbe production of antibodies to the surface antigen of the hepatitis b virus in an experiment on animals]. | the biological assay for the determination of hbsag in gamma globulin is proposed. the assay is based on the immunizing action of immune complexes and some specific features of secondary immune response. for this purpose, the highly purified preparation of hbsag is injected into guinea pigs. subsequently the animals receive human gamma globulin. an increase in the titer of anti-hbsag antibodies in the animals preimmunized with the antigen is indicative of the presence hbsag in human gamma globul ... | 1989 | 2481912 |
| characterization of the binding sites for glutaraldehyde-polymerized albumin on purified woodchuck hepatocyte plasma membranes. | highly purified woodchuck hepatocyte plasma membranes demonstrated tight specific binding to glutaraldehyde-polymerized serum albumin immobilized on sepharose macrobeads. this phenomenon was characterized in detail and used for recognition of the plasma membrane constituents involved in binding of the albumin polymer. the hepatocyte membrane-polyalbumin interaction was found to be ligand-specific, saturable, and time-dependent. other characteristics of a specific receptor-ligand interaction were ... | 1989 | 2491821 |
| [a study on primary liver cancer in tree shrews induced by human hepatitis b virus and aflatoxin b1]. | among 41 tree shrews exposed to aflatoxin b1(afb1), 17 were experimental infected by human hepatitis b virus (hhbv) and 24 were uninfected. after 158 weeks, 9 cases (52.94%) of primary liver cancer (plc) were found out of the 17 tree shrews infected by hhbv and only 3 cases (12.5%) developed plc in the 24 uninfected animals. significant difference of plc incidence was seen between the hhbv-infected and uninfected groups (p less than 0.05). moreover, 1/9 of the tree shrews that had been infected ... | 1989 | 2505943 |
| bilateral posterior parietal atrophy in an infant rhesus monkey (macaca mulatta). | a case of severe neurological deficiency syndrome marked by visual impairment, motor disturbances, and bilateral extensive glial scarring of the posterior parietal cortex is described in an infant rhesus monkey. although morphologically resembling perinatal asphyxia, the possibility of a perinatal or postnatal herpesvirus simiae infection is discussed. | 1989 | 2540335 |
| discrimination between twenty isolates of herpesvirus simiae (b virus) by restriction enzyme analysis of the viral genome. | twenty isolates, obtained from adult breeding monkeys, were all identified as herpesvirus simiae (b virus) by neutralisation with polyclonal b virus antiserum. subsequent analysis of restriction enzyme profiles produced by digestion of dna from the isolates enabled discrimination to be made between them. in particular cynomolgus monkey isolates could be distinguished from those of rhesus animals. one isolate (isolate 9) could not be typed either as b virus or as the antigenically related herpesv ... | 1989 | 2543157 |
| 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 |
| herpesvirus simiae contamination of primary rhesus monkey kidney cell cultures. cdc recommendations to minimize risks to laboratory personnel. | 1989 | 2556236 | |
| 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 |
| hepatitis b surface antigen binds to human serum albumin cross-linked by transglutaminase. | it has been postulated that polymerized human serum albumin may play a role in the infection of hepatocytes by hepatitis b virus, because both the envelope of hepatitis b virus (hbsag) and hepatocytes exhibit binding activity for human serum albumin after cross-linking by glutaraldehyde. since glutaraldehyde-dependent cross-linking of albumin molecules is not likely to occur in vivo, we considered the possibility that albumin may be polymerized by the action of transglutaminase enzymes present i ... | 1989 | 2565285 |
| serological survey for viral diseases in the cayo santiago rhesus macaque population. | the free-ranging population of rhesus monkeys (macaca mulatta) on cayo santiago was sero-surveyed for human measles, simian virus 40, b virus (herpes simiae), rhesus cytomegalovirus, human and simian retroviruses and encephalomyocarditis virus to determine the prevalence of these viruses in the colony. the results of this study indicate that the colony is free of sv40, htlviii (hiv-1), stlviii (siv) and srv1; has a low prevalence of measles and emcv; and high prevalence rates for b virus, cmv an ... | 1989 | 2571176 |
| 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 |
| enhancement of humoral immune responses against viral vaccines by a non-pyrogenic 6-o-acylmuramyldipeptide and synthetic low toxicity analogues of lipid a. | 6-o-acyl derivatives of n-acetylmuramyl-l-alanyl-d-isoglutamine (mdp) and synthetic, low toxicity lipid-a analogues were examined for their ability to enhance the potency of current viral vaccines. 6-o-(2-tetradecylhexadecanoyl)-mdp (b30-mdp) in non-irritative vehicles such as physiological saline, phosphate-buffered saline (pbs), squalene-pbs emulsion, intralipid or liposomes, significantly stimulated the primary and secondary antibody production of guinea-pigs against influenza split or subuni ... | 1989 | 2718605 |
| 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 |
| [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 |
| production of hepatitis b virus surface antigen containing pre-s1 and pre-s2 domains by chinese hamster ovary cells. | we have established transformed chinese hamster ovary cells, which secrete hepatitis b virus surface antigen containing both pre-s1 and pre-s2 domains into culture medium, by using the autologous s gene promoter. | 1989 | 2764727 |
| 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 |
| molecular mimicry between a uveitopathogenic site of s-antigen and viral peptides. induction of experimental autoimmune uveitis in lewis rats. | s-antigen (s-ag) is a well characterized 45,000 m.w. photoreceptor cell protein. when injected into susceptible animal species, including primates, it induces an experimental autoimmune uveitis, a predominantly t cell-mediated autoimmune disease of the retina and uveal tract of the eye, and of the pineal gland. in this study we found an amino acid sequence homology between a uveitopathogenic site of s-ag, several viral proteins and one additional nonviral protein. an experimental autoimmune uvei ... | 1990 | 1689349 |