Publications
| Title | Abstract | Year(sorted ascending) Filter | PMID Filter |
|---|
| 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 |
| 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 |
| 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 |
| reduced duck hepatitis b virus viraemia in ducklings coinfected with the immunodepressive reticuloendotheliosis virus. | coinfection of avian hosts by duck hepatitis b virus (dhbv) and reticuloendotheliosis virus (rev) was studied to assess the effect of immunodepression by rev on the replication of dhbv. one-day-old ducklings, domestic chickens, and turkey poults were inoculated either with dhbv or dhbv and rev and were bled and weighed at regular intervals. dhbv infection as manifested by viraemia and dhbv dna in liver was established only in ducklings. all chickens and turkeys were negative for dhbv dna in seru ... | 1990 | 2160513 |
| anti-influenza virus activity of the compound ly253963. | the compound ly253963 (1,3,4-thiadiazol-2-ylcyanamide) inhibited the in vitro replication of representative influenza a and b viruses in madin-darby canine kidney (mdck) cells at concentrations of 1-3.2 micrograms/ml. the yield of an influenza a (h3n2) virus in primary rhesus monkey kidney (rmk) cells was inhibited at 0.1-0.3 micrograms/ml. however, similar concentrations were inhibitory for the growth of uninfected mcdk or rmk cells. combination drug studies generally found indifferent interact ... | 1990 | 2080866 |
| ocular histopathologic findings in a case of human herpes b virus infection. | a 37-year-old male laboratory technician who sustained a cutaneous penetrating wound from a rhesus monkey developed a progressive ascending encephalomyelitis due to culture-proven herpes b virus (herpesvirus simiae) infection. he died 6 weeks after his injury despite acyclovir and ganciclovir treatment that was initiated after central nervous system symptoms developed. histopathological examination of the patient's left eye revealed a multifocal necrotizing retinitis associated with a vitritis, ... | 1990 | 2159276 |
| seroprevalence of b virus (herpesvirus simiae) antibodies in a naturally formed group of rhesus macaques. | eighty-two percent of a group of rhesus monkeys removed from cayo santiago were seropositive for b virus (herpesvirus simiae) antibodies. similar results were obtained from the cayo santiago macaque population two decades ago and from feral indian rhesus monkeys. thus it is likely that b virus has been enzootic in the cayo santiago population since 1938, when the colony was established with stock imported from india. | 1990 | 2160017 |
| a cross sectional survey for b virus antibody in a colony of group housed rhesus macaques. | a systematic sampling technique was used in combination with a highly sensitive and specific elisa to provide unbiased age-specific prevalence estimates of b virus antibody in rhesus monkeys housed in three different outdoor breeding corrals. among 146 sampled monkeys, 97% of animals 2.5 years and older were seropositive, while only 22% of younger animals were seropositive. neither gender nor social dominance ranking were predictive of b virus antibody status. the strong age association was not ... | 1990 | 2162979 |
| vectors, promoters, and expression of genes in chick embryos. | transgenic chickens were produced by injecting the day-1 egg with 10(5) infectious particles of a replication-competent virus based on the schmidt-ruppin a strain of rous sarcoma virus. the chickens were resistant to transforming subgroup a virus containing the src gene but not the corresponding subgroup b virus. transgenic chickens producing bovine growth hormone (bgh) were generated using a modified virus containing the bryan high titre polymerase gene. the virus was constructed with the bgh g ... | 1990 | 2170640 |
| 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 |
| isolation of measles virus in primary rhesus monkey cells from a child with acute interstitial pneumonia who cytologically had giant-cell pneumonia without a rash. | the isolation of measles virus in primary rhesus monkey kidney cells (prmk) in patients with documented giant-cell pneumonia who have presented without a rash is limited. the diagnosis usually is made by cytologic examination of nasal or bronchial secretions in which characteristic multinucleated giant cells with intranuclear and intracytoplasmic inclusion bodies are observed. the diagnosis of giant-cell pneumonia has been associated with measles virus but not exclusively. canine distemper, herp ... | 1990 | 2220674 |
| 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 |
| nci-h292 as an alternative cell line for the isolation and propagation of the human paramyxoviruses. | primary rhesus monkey kidney (mk) cells have long been the cells of choice for isolation and propagation of the human paramyxoviruses (parainfluenza 1, 2, 3, 4a, 4b, and mumps). however, problems with the supply and cost of mk cells and the presence of endogenous viruses, including herpes b virus and sv-5, necessitated a search for an alternative cell line. continuous cell cultures of human origin (l132, a-549, hut-292, hek, g-293, g-401, a-498, a-704, caki-1, rd) and simian origin (llc-mk2, bsc ... | 1990 | 2260924 |
| 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 |
| enhancement of antibody responses to influenza b virus haemagglutinin by use of a new adjuvant formulation. | mice and guinea pigs were immunized with the haemagglutinin (ha) of influenza b-ussr/100 virus, either in syntex adjuvant formulation-1 (saf-1) or in saline. antibody titres were determined by elisa, haemagglutination inhibition and virus neutralization. animals immunized with ha in saf-1 had significantly higher antibody titres than did animals immunized with ha in saline. both 3-week-old and 13 1/2-month-old mice had greater and more uniform antibody responses to ha in saf-1 than to ha in sali ... | 1990 | 2316284 |
| 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 |
| fatal herpesvirus simiae (b virus) infection in a patas monkey (erythrocebus patas). | 1990 | 1965586 | |
| animal transmission of enteric non-a, non-b hepatitis infection to macaca mulatta by faeco-oral route. | m. mulatta monkeys were inoculated faeco-orally by enteric non-a, non-b virus to study the development of clinical, biochemical, histopathological and serological changes in the blood and liver. pooled stool samples positive for putative non-a, non-b viral antigen by micro-elisa and aggregated viral particles by immune electron microscopy, were administered in two m. mulatta monkeys. biochemical, histopathological and serological changes were seen in the blood and liver and excretion of 27 nm vi ... | 1990 | 1693136 |
| 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 |
| adjuvant formulations and their mode of action. | we have developed an adjuvant formulation (saf) consisting of a synthetic muramyl dipeptide analogue (n-acetylmuramyl-l-threonyl-d-isoglutamine) in a squalane-pluronic polymer emulsion. used with a variety of antigens saf elicits cell-mediated immunity and antibodies of protective isotypes (igg2a in the mouse). saf augments responses to influenza virus haemagglutinin and hepatitis b virus surface antigen. vaccines using saf have protected guinea pigs against genital herpes simplex virus infectio ... | 1990 | 1966859 |
| 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 |
| 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 |
| immunogenic domains of hepatitis delta virus antigen: peptide mapping of epitopes recognized by human and woodchuck antibodies. | hepatitis delta virus (hdv) is a defective rna virus which is dependent on hepatitis b virus for essential helper functions. only a single highly basic phosphoprotein, hdv antigen (hdag), is expressed by the hdv genome during infection in humans. antibody directed to hdag is important in the diagnosis of hdv infection, and it is likely but not yet proven that the immune response to hdag provides significant protection against subsequent exposures to hdv. in an effort to map the antigenic domains ... | 1990 | 1689390 |
| 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 |
| 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 |
| improvement of hepatitis b vaccine by the use of a new adjuvant. | humoral and cellular immune responses of mice and guinea-pigs to hepatitis b virus surface antigen when alum-precipitated or administered with syntex adjuvant formulation (saf) were compared. two doses of hbsag in saf were sufficient to elicit antibody responses, and using saf the dose of antigen could be reduced to one-tenth of that required to elicit antibody responses by alum-adjuvanted hbsag. the use of saf increased and made more consistent the antibody responses in young mice and in strain ... | 1991 | 1872014 |
| genetic analysis of the rous sarcoma virus subgroup d env gene: mammal tropism correlates with temperature sensitivity of gp85. | subgroup d avian sarcoma and leukosis viruses can penetrate a variety of mammalian cells in addition to cells from their natural host, chickens. sequences derived from the gp85-coding domain within the env gene of a mammal-tropic subgroup d virus (schmidt-ruppin d strain of rous sarcoma virus [sr-d rsv]) and a non-mammal-tropic subgroup b virus (rous-associated virus type 2) were recombined to map genetic determinants that allow penetration of mammalian cells. the following conclusions were base ... | 1991 | 1848317 |
| 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 |
| 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 |
| natural and experimental infection of wild mallard ducks with duck hepatitis b virus. | wild duck populations were investigated over a 4 year period for duck hepatitis b virus (dhbv) infection and liver disease. it appeared that dhbv is endemic in wild migratory mallards from france and the u.s.a., although neither hepatocellular carcinoma nor viral dna integration could be detected in liver samples examined. the follow up of natural infection indicated that wild mallards developed significantly higher serum titres to dhbv dna than pekin ducks. the results of experimental transmiss ... | 1991 | 1993878 |
| 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 |
| 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 |
| a percutaneous liver biopsy technique in ducks (anas platyrhynchos) experimentally infected with duck hepatitis b virus. | aylesbury ducks (anas platyrhynchos) chronically infected with the duck hepatitis b virus provide a useful model for studying hepadna-virus infection, replication and the effects of antiviral therapy. in these studies, it is necessary to have an effective method for obtaining repeat liver specimens for histological and molecular analyses. we have therefore developed a percutaneous liver biopsy technique which has a low rate of complications, can be performed at repeated intervals, and provides s ... | 1991 | 1921325 |
| [hepatitis b and primary cancer of the liver: recent data on the role of b virus in oncogenesis]. | although epidemiologic studies have clearly demonstrated the importance of the hepatitis b virus in the genesis of hepatocellular carcinoma, the molecular basis for this tumorigenic effect is still under debate. studies of woodchucks infected with a virus closely related to the human hepatitis b virus suggest that integration of the viral dna in the host genome often plays a direct role by activating myc cellular oncogenes through insertional mutagenesis. a similar mechanism involving other cell ... | 1991 | 1850121 |
| characterization of infectious and defective cloned avian hepadnavirus genomes. | the infectivity in vivo, replication competence in vitro, and expression of viral genes of several molecularly cloned duck hepatitis b virus (dhbv) genomes were investigated. in addition, replication competence, core protein expression, and secretion of viral proteins were investigated for a grey heron hepatitis b virus genome. except two, all dhbv isolates tested induced a systemic infection in pekin ducks when injected as cloned viral dna into the liver. after transfection of chicken hepatoma ... | 1991 | 1926780 |
| herpesvirus simiae (b virus) antibody response and virus shedding in experimental primary infection of cynomolgus monkeys. | four cynomolgus monkeys (macaca fascicularis) were inoculated in the lips and tongues with b virus. virus shedding and antibody responses were monitored for up to 50 days postinfection. virus was isolated from the oral cavities of all monkeys at 6 days postinfection despite the absence of observable lesions. virus was not isolated from genital swabs or serum. antibodies to both b virus and herpes simplex virus were detected by neutralization between days 8 and 12. virus-specific igm and igg anti ... | 1991 | 1658484 |
| development of immunogenic recombinant oka varicella vaccine expressing hepatitis b virus surface antigen. | recombinant oka varicella vaccine expressing hepatitis b virus (hbv) surface antigen (hbs) was constructed by inserting the hbs gene into the viral thymidine kinase (tk) gene and was examined for its immunogenicity in guinea-pigs. the hbs gene encoding 25 amino acids of pres2 and the whole of the s region was inserted into the tk gene of the cloned plasmid. the chimeric plasmid dna and oka varicella vaccine dna were cotransfected and recombinant virus was isolated after immunofluorescence screen ... | 1991 | 1646279 |
| [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 |
| a functional hepatitis b virus x protein produced in insect cells. | we have constructed a recombinant baculovirus from autographa californica nuclear polyhedrosis virus, called acx, that expresses the gene encoding the hepatitis b virus x protein in infected spodoptera frugiperda (sf21ae) insect cells. a 16.5-kda monomer and a 33-kda dimer of the x protein were detected in extracts from acx-infected cells on immunoblots using a polyclonal anti-x antibody. the biological activity of the insect cell-produced x protein was assayed by fusing acx-infected sf21ae cell ... | 1991 | 1660211 |
| persistent reduction of b virus (herpesvirus simiae) seropositivity in rhesus macaques acquired for a study of renal allograft tolerance. | one hundred and two rhesus macaques were used in a study of renal allograft tolerance. each animal was monitored serologically more than one time to determine its b virus (herpesvirus simiae) antibody status. the follow-up period for some individuals was 3 years, extending from 1986 to 1989. the accumulated test results eventually provided an opportunity to retrospectively support a contention that a small research colony of rhesus macaques could become and remain b virus seronegative if the ani ... | 1991 | 1667193 |
| immunological evaluation of the multiple antigen peptide (map) system using the major immunogenic site of foot-and-mouth disease virus. | the multiple antigenic peptide (map) system for presenting epitopes to the immune system has been studied with an immunogenic foot-and-mouth disease virus (fmdv) peptide comprising amino acids 141-160 of protein vp1. neutralizing antibody responses known to protect guinea-pigs against challenge infection were obtained with a single inoculation of 0.8-4 micrograms of peptide, presented as an octamer or a tetramer, whereas 20 micrograms of a dimer were required to evoke a similar level of antibody ... | 1991 | 1652552 |
| 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 |
| [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 |
| naturally occurring point mutation in the c terminus of the polymerase gene prevents duck hepatitis b virus rna packaging. | a duck hepatitis b virus (dhbv) genome cloned from a domestic duck from the people's republic of china has been sequenced and exhibits no variation in sequences known to be important in viral replication or generation of gene products. intrahepatic transfection of a dimer of this viral genome into ducklings did not result in viremia or any sign of virus infection, indicating that the genome was defective. functional analysis of this mutant genome, performed by transfecting the dna into a chicken ... | 1992 | 1309904 |
| biology of b virus in macaque and human hosts: a review. | b virus is a zoonotic alpha-herpesvirus enzootic in asian monkeys of the genus macaca. at least 25 cases of human disease caused by b virus have occurred to date, leading to death in 16 instances. advances in the technology available for the diagnosis of b virus infection and in the agents for its treatment are improving the prognosis for cases in human beings. efforts are under way at several institutions in the united states to establish b virus-free colonies of rhesus macaques for use in biom ... | 1992 | 1313312 |
| 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 |
| effects of phyllanthus plant extracts on duck hepatitis b virus in vitro and in vivo. | the effects of extracts of five australian phyllanthus species (p. hirtellus, p. gunnii, p. gasstroemii, p. similis and p. tenellus), other plant extracts and the antiviral drug foscarnet on duck hepatitis b virus (dhbv) endogenous dna polymerase (dnap) activity were compared. all 5 phyllanthus species caused 50% inhibition at concentrations of dry weight between 350-800 micrograms/ml, which is comparable with the effect described for p. amarus on the dnap of human and woodchuck hepatitis b viru ... | 1992 | 1416905 |
| 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 |
| 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 |
| an attempt to eradicate herpesvirus simiae from a rhesus monkey breeding colony. | in the fall of 1987 an attempt to establish a herpesvirus simiae (b-virus)-negative rhesus monkey (macaca mulatta) breeding colony was initiated at the armstrong laboratory. a serologic testing program was used to identify all monkeys into groups that were either positive or negative to b-virus based on serologic tests. segregation of the groups allowed the creation of breeding harems that were exclusively seropositive or -negative to b-virus. animals that were serologically positive were kept i ... | 1992 | 1334170 |
| 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 |
| pharmacokinetics and metabolism of racemic 2',3'-dideoxy-5-fluoro-3'-thiacytidine in rhesus monkeys. | 2',3'-dideoxy-5-fluoro-3'-thiacytidine (ftc) is a nucleoside analog that selectively inhibits human immunodeficiency and hepatitis b viruses in vitro. in this study, the preclinical pharmacokinetics of racemic ftc in rhesus monkeys following intravenous and oral administration were characterized. the terminal half-life of ftc was independent of the route of administration and averaged 1.34 +/- 0.18 h (mean +/- standard deviation). total clearance of ftc was moderate to high, averaging 1.49 +/- 0 ... | 1992 | 1336946 |
| activation of b virus (herpesvirus simiae) in chronically immunosuppressed cynomolgus monkeys. | three of 14 cynomolgus monkeys given the highest dose of an immunosuppressive drug in a 6-month toxicology study developed b virus (herpesvirus simiae) oral lesions after 3 months of dosing. this necessitated early removal of all high-dose monkeys from the study due to concerns related to b virus. the incidence and severity of parasitic (oesphagostomum sp.) lesions of the large intestine were also increased in high-dose animals. both b virus and oesophagostomum are enzootic in macaques, and the ... | 1992 | 1351111 |
| 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 |
| 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 |
| 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 |
| hepatitis b virus envelope l protein particles. synthesis and assembly in saccharomyces cerevisiae, purification and characterization. | the hepatitis b virus envelope gene encodes three transmembrane proteins in frame; s, the product of s gene; m, the product of m (pre-s2 + s) gene; and l, the product of l (pre-s1 + pre-s2 + s) gene. unlike the s and m proteins, attempts to efficiently synthesize l proteins and assemble them into l protein particles in various eukaryotic cells have been unsuccessful, probably because of the presence of the pre-s1 peptide with an unknown function which appears to be inhibitory to the host secreto ... | 1992 | 1370486 |
| human immunodeficiency virus type 1 major neutralizing determinant exposed on hepatitis b surface antigen particles is highly immunogenic in primates. | hepatitis b surface antigen (hbsag) produced by recombinant dna technology is now widely and safely used worldwide for hepatitis b vaccination. we used the hbsag particle as a carrier molecule for presentation of selected human immunodeficiency virus type 1 (hiv-1) determinants to the immune system. immunization of rhesus monkeys with an hbsag chimera carrying the hiv-1 envelope major neutralizing determinant allowed us to generate proliferative t-cell responses and, in some cases, neutralizing ... | 1992 | 1548782 |
| relationship between superoxide dismutase (sod) and viral liver diseases. | immunohistochemical evaluation of cu, zn- and mn-superoxide dismutase (sod) activity in various viral liver diseases was performed by the peroxidase-conjugated antibody indirect method. anti-human cu, zn-sod (rabbit) and anti-human mn-sod (guinea-pig) derived and purified from sod of human erythrocytes and placentas were used to determine sod distribution in liver tissues. sod in the liver tissues was detected in 68 inpatients of our unit. they consisted of 23 cases with chronic hepatitis caused ... | 1992 | 1320579 |
| 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 |
| cells transfected with human interleukin 6 cdna acquire binding sites for the hepatitis b virus envelope protein. | earlier studies revealed that human interleukin 6 (il-6) contains recognition sites for the hepatitis b virus (hbv) envelope (env) protein, and that il-6 and anti-il-6 antibodies, respectively, inhibited the interaction of cells expressing a receptor for hbv with the pres(21-47) segment of the hbv env protein, encompassing the complementary attachment site for il-6. this suggested that il-6 mediates hbv-cell interactions. we report that: (a) chinese hamster ovary cells transfected with human il- ... | 1992 | 1334115 |
| 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 |
| a novel particulate influenza vaccine induces long-term and broad-based immunity in mice after oral immunization. | the immunogenicity of a novel particulate oral influenza vaccine was examined in terms of antibody response and protection in mice. oral immunization with chicken erythrocytes (crbc) adsorbed with gamma-irradiated influenza a virus induced high levels of immunoglobulin g antibodies and protection in the lung compared with gamma-irradiated virus administered alone or crbc. immunoglobulin a antibodies were the predominant antibodies in nasal washings, and their presence did not correlate with prot ... | 1992 | 1731094 |
| epitopes recognized by antibodies to denatured core protein of hepatitis b virus. | particulate and denatured core protein as well as e-antigen (hbe) of hepatitis b virus (hbv) differ in part immunologically but this has not been studied in sufficient detail. therefore, in this study the b-cell immune response to native and denatured hbv core protein which both can exhibit hbe-specific epitopes was examined using a panel of mouse mabs and rabbit polyclonal antibodies to native and denatured core protein and polyclonal anti-hbe/anti-hbc antibodies from sera of infected patients. ... | 1993 | 7679466 |
| duck hepatitis b virus (dhbv) infection in indian domestic ducks: a pilot study. | one hundred and two apparently healthy indian domestic ducks from the poultry research station, madras were screened for duck hepatitis b virus (dhbv) infection by; 1. screening for the duck hepatitis b virus surface antigen (dhbsag) in their sera using hepatitis b virus (hbv) reagents, 2. screening for dhbsag using specific duck hepatitis b virus (dhbv) reagents and 3. demonstration of dhbv dna using dhbv dna probe by dot blot hybridisation. while 5 ducks (4.9%) were consistently positive with ... | 1993 | 8109057 |
| saccharomyces cerevisiae can release hepatitis b virus surface antigen (hbsag) particles into the medium by its secretory apparatus. | we constructed a plasmid that directs the synthesis and secretion of hepatitis b virus (hbv) surface antigen (hbsag) particles by saccharomyces cerevisiae. this plasmid contains a proteinase-resistant hbsag m (m-p31c) gene fused at its 5'-terminus with a chicken-lysozyme signal peptide (c-sig) gene, which is placed under the yeast gld (glyceraldehyde-3-phosphate dehydrogenase gene) promoter. the products encoded by the "c-sig+m-p31c" (lm-p31c) gene were synthesized and assembled themselves into ... | 1993 | 7764388 |
| a hepatitis b virus pre-s-retinoic acid receptor beta chimera transforms erythrocytic progenitor cells in vitro. | in this report, we investigated the transforming properties of retinoic acid receptor beta (rar beta). the v-erba protein, which is the viral oncogenic homologue of the thyroid hormone receptor, was replaced by either the complete rar beta (beta r) or a hepatitis b virus pre-s-rar beta (h beta r) hybrid product in an avian erythroblastosis virus-based vector. in chicken hematopoietic cells, the h beta r protein was able to transform erythroid progenitor cells, whereas no such transformation was ... | 1993 | 8093562 |
| infrequent shedding and transmission of herpesvirus simiae from seropositive macaques. | the epizootiologic properties of herpesvirus simiae (b virus) were studied in singly housed macaques (macaca mulatta and m. fascicularis) in a biomedical vivarium to determine whether commonly encountered environments and procedures such as quarantine, breeding, caesarean section, parturition, and social stress induced virus shedding and transmission. macaques were tested serologically and for infectious virus. oral, conjunctival, and vaginal swab samples were obtained repeatedly. virus excretio ... | 1993 | 8158977 |
| disseminated b virus infection in a cynomolgus monkey. | a cynomolgus monkey (macaca fascicularis) was euthanatized 1 week following dystocia because of severe peritonitis. histologic examination revealed lesions characteristic of herpesvirus infection in lungs, liver, spleen, bone marrow, uterus, and adrenal gland, and on the serosal surface of intestines, pancreas, and reproductive tract. immunohistochemical studies on liver and lungs revealed herpes b-like antigens in the lesions. b virus was isolated from serum. as systemic b-virus infection was n ... | 1993 | 8158978 |
| immunization with recombinant woodchuck hepatitis virus nucleocapsid antigen or hepatitis b virus nucleocapsid antigen protects woodchucks from woodchuck hepatitis virus infection. | woodchucks were immunized with recombinant woodchuck hepatitis virus (whv) nucleocapsid antigen (whcag) or hepatitis b virus (hbv) nucleocapsid antigen (hbcag) and challenged with 10(6) whv id50. six out of six woodchucks immunized with whcag and four out of six immunized with hbcag were protected from whv infection. woodchucks immunized with whcag or hbcag developed high serum antibody titres against whcag or hbcag. antibodies against whc and hbc displayed little cross-reactivity (< 1%). this c ... | 1993 | 8322485 |
| [production of transgenic rabbits by micro injection]. | the feasibility of using whole animal instead of bioreactor in genetic engineering has been investigated with transgenic domestic rabbits. the gene chosen is the surface gene (s gene) of hepatitis b virus. two plasmids were specifically constructed for this purpose, phbv3.0 contains the promoter pre s gene and a part of c gene of the virus; while mt-sa, the s gene and mouse mt promotor. these plasmids were made linear by suitable restriction endonuclease before they were transferred into malepro ... | 1993 | 8329213 |
| unique pres sequence in a gibbon-derived hepatitis b virus variant. | a unique hepatitis b virus (hbv) variant has been identified in a gibbon (hylobates lar) which could be passed to a chimpanzee by experimental inoculation. this hbv variant had been shown to have no reactivity to a monoclonal anti-pres2 antibody (pres2 mab 116-34) differentiating it from all human hbv specimens tested. this gibbon sera also was not recognized by an anti-pres1 mab which binds the pres1 hepatocyte receptor region, amino acids 27-35. in this paper, we report the dna sequence of the ... | 1993 | 8363598 |
| polymerase chain reaction for detection of herpesvirus simiae (b virus) in clinical specimens. | a polymerase chain reaction (pcr) was designed which is specific to macaca fascicularis (cynomolgus monkey) isolates of b virus. the pcr primers produced the expected 188 basepair product from the cyno 2 strain and seven other cynomolgus monkey isolates of b virus. oligomer hybridization with a 31-mer oligonucleotide was used to confirm the origin of this product. the pcr failed to amplify dna of epstein-barr virus, cytomegalovirus, varicella-zoster virus, and other alphaherpesviruses (herpes si ... | 1993 | 8392323 |
| epidemiology of cercopithecine herpesvirus 1 (b virus) infection and shedding in a large breeding cohort of rhesus macaques. | the epidemiology of b virus infection in a large (n = 157) cohort of rhesus macaques at the california regional primate research center was evaluated prospectively from september 1989 through january 1991 by serial physical examinations, a behavioral substudy (n = 51), and repeated diagnostic testing. half were b virus antibody-positive at baseline; subsequently, incident cases of infection were documented through serology alone (42) or with virus isolation (5). eight recurrent infections and a ... | 1993 | 8380607 |
| competitive radioimmunoassay to detect antibodies to herpes b virus and sa8 virus. | a monoclonal competitive radioimmunoassay (compriam) which detects antibody to herpesvirus simiae (b virus) in monkey and human sera and antibody to sa8 virus in monkey sera but not antibody to herpes simplex virus in human sera is described. of 232 serum samples from wild-caught cynomolgus monkeys, 117 serum samples were positive when tested by compriam. the results were in close agreement (97.5%) with b virus neutralizing antibody results on the same sera. sera from 97 wild-caught rhesus monke ... | 1993 | 8385154 |
| antibodies to polymerized albumin in woodchuck hepatitis virus infection. | polymerized human serum albumin may play a role in the entry of hepatitis b virus into hepatocytes, and antibodies to polyalbumin that frequently appear during acute hepatitis may aid the process of viral clearance. we developed an enzyme-linked immunosorbent assay for antibodies to polymerized woodchuck albumin to enable us to evaluate further the role of these antibodies in an animal model system. sera from 17 uninfected adult woodchucks and 8 newborns showed no binding to control plates coate ... | 1993 | 8476506 |
| [recombinant oka varicella vaccine as a live hepatitis b virus vaccine]. | recombinant oka varicella-hepatitis b virus (hbv) vaccine was constructed by inserting the hbv surface antigen (hbsag) gene coding partial pres2 and whole s regions into the viral thymidine kinase gene. hbsag was expressed in the cytoplasm of infected cells. intracellular hbsag (26k and 30k) was n- and o-glycosylated, sialylated, and secreted into the supernatant as 30k and 35k hbsag particles. recombinant virus induced antibody response to both varicella-zoster virus and hbsag in guinea pigs an ... | 1993 | 8381884 |
| comparative anti-influenza virus activity of 2'-deoxy-2'-fluororibosides in vitro. | the anti-influenza virus activity of 2'-deoxy-2'-fluoroguanosine was determined in cell culture and in explants of human respiratory epithelium by yield reduction assay. the concentration causing at least 1.0 log10 reduction in influenza a (h3n2) virus yield (ec90) at 24 h was 2.5 micrograms/ml in primary rhesus monkey kidney and 12 micrograms/ml in madin-darby canine kidney (mdck) cells, compared to 0.5 micrograms/ml and 0.9 micrograms/ml, respectively, for ribavirin. the estimated therapeutic ... | 1993 | 8215305 |
| duck hepatitis b virus infection, aflatoxin b1 and liver cancer in ducks. | the association between chronic infection by hepadnaviruses isolated from human (hbv), woodchuck (whv), ground squirrel (gshv) and development of hepatocellular carcinoma (hcc) in their respective hosts is well established (reviewed in [11, 15, 17]). by contrast, the association of duck hepatitis b virus (dhbv) infection with hcc is less documented. pekin ducks congenitally infected with dhbv and followed for several years throughout the world do not develop liver tumors: hcc has been found only ... | 1993 | 8260880 |
| direct cloning and expression of pcr amplified dna and rna sequences: application to the hepadnaviruses nucleocapsid proteins. | gene amplification may benefit from the construction of primers that augments the speed at which cloning and protein expression proceeds. such primers include ecori or hindiii linkers as well as an in phase initiation or termination codon. pcr was carried out directly from viral particles of human hepatitis b virus (hbv) and woodchuck hepatitis virus (whv) without dna purification and from rna extracted from whv infected liver. amplified products were directly cloned in the pkk223-3 expression v ... | 1993 | 8514845 |
| new enzyme immunoassays for the serologic detection of woodchuck hepatitis virus infection. | the woodchuck and the woodchuck hepatitis virus (whv) have been used as a model of hepatitis b virus infection and its disease sequelas. serologic responses to whv infection have been described in previous reports from this laboratory by using virus-specific radioimmunoassays (rias) for whv surface antigen, antibody to whv core antigen, and antibody to whsag. in this study, we developed and evaluated new enzyme immunoassays (eias) for these whv serologic markers. relative to the established rias ... | 1993 | 8216715 |
| duck hepatitis b virus infection, aflatoxin b1 and liver cancer in domestic chinese ducks. | the oncogenicity of duck hepatitis b virus (dhbv) is unclear since hepatocellular carcinomas (hccs) have been reported only in domestic ducks in qidong, an area of china where hepatitis b virus (hbv) and aflatoxin b1 (afb1) are risk factors for liver cancer in man. in order to better define the association between dhbv infection, afb1 and hcc we analysed a series of 16 duck liver samples collected from local farms in qidong. hcc was found in eight and cirrhosis in one of these samples. furthermo ... | 1994 | 8286190 |
| different in situ expression of insulin-like growth factor type ii in hepatocellular carcinoma. an in situ hybridization and immunohistochemical study. | reexpression of the insulin-like growth factor type ii (igf-ii) gene has recently been described in hepatocellular carcinoma (hcc). in this study, we used a nonisotopic in situ hybridization method to analyze the expression of igf-ii mrna in a series of 28 hccs arising on cirrhotic and noncirrhotic livers. an immunohistochemical method was used to detect igf-ii peptide. hepatitis b virus (hbv) status and the histological differentiation degree were also evaluated. increased expression of igf-ii ... | 1994 | 8162257 |
| molecular events in the pathogenesis of hepadnavirus-associated hepatocellular carcinoma. | chronic hepadnavirus infection is associated with hepatocellular carcinoma (hcc) in natural hosts such as humans, woodchucks, and beechey ground squirrels. several possible oncogenic mechanisms have been identified, including a potential role of the hepadnavirus x (hbx) gene, which transactivates transcription regulated by certain cis-acting sequences, e.g. regulatory sequences of the hepatitis b virus (hbv) and heterologous regulatory sequences of other viruses and cellular genes. the oncogenic ... | 1994 | 8198385 |
| characterization of the antiviral effects of 2' carbodeoxyguanosine in ducks chronically infected with duck hepatitis b virus. | this study was carried out to evaluate benefits and limitations of long-term therapy of hepatitis b virus infections with a nucleoside analog inhibitor of virus replication. the model we used was the domestic duck chronically infected with duck hepatitis b virus by in ovo infection. 2' carbodeoxyguanosine was used as an inhibitor of viral dna synthesis. in all animals examined there was a reduction in virus production during therapy. a dose of 2' carbodeoxyguanosine of 10 micrograms/kg every oth ... | 1994 | 8294097 |
| spontaneous development of anti-hepatitis b virus envelope (anti-idiotypic) antibodies in animals immunized with human liver endonexin ii or with the f(ab')2 fragment of anti-human liver endonexin ii immunoglobulin g: evidence for a receptor-ligand-like relationship between small hepatitis b surface antigen and endonexin ii. | in a previous study, we have identified endonexin ii (e-ii) on human liver plasma membranes as a specific, ca(2+)-dependent, small hepatitis b surface antigen (hbsag)-binding protein. in this article, we describe the spontaneous development of anti-hbs antibodies in rabbits immunized with native or recombinant human liver e-ii and in chickens immunized with the f(ab')2 fragment of rabbit anti-human liver e-ii immunoglobulin g. anti-hbs activity was not observed in rabbits immunized with rat live ... | 1994 | 8107214 |
| characterization and biosynthesis of the woodchuck hepatitis virus e antigen. | the biosynthesis of the secretory core gene product of the woodchuck hepatitis virus (whv) was studied in human cells. we have shown that the whv e antigen was a n-glycosylated (most likely a diglycosylated) protein, with an apparent m(r) of 24k. to demonstrate that the whv precore protein was correctly processed in human cells, we engineered chimeric proteins in which signal peptides or arginine-rich domains of whv and hepatitis b virus (hbv) precore proteins were exchanged. our results showed ... | 1994 | 8113724 |
| identification of factor-binding sites in the duck hepatitis b virus enhancer and in vivo effects of enhancer mutations. | hepatitis b viruses (hepadnaviruses) can cause chronic, productive infections of hepatocytes. analyses of the enhancers and promoters of these viruses in cell lines have suggested a requirement of these elements for liver-enriched transcription factors. in this study, a minimum of seven factor-binding sites on the duck hepatitis b virus enhancer were detected by dnase i footprinting using duck liver nuclear extracts. among the sites that were tentatively identified were one c/ebp-, one hnf1-, an ... | 1994 | 8139013 |
| dot blot hybridization assay for the detection of duck hepatitis b virus dna among healthy indian country ducks. | a dna molecular hybridization technique employing duck hepatitis b virus (dhbv) dna of 3.0 kilobase pairs as a probe was used to screen for the presence of dhbv dna in blood samples, collected from 90 apparently healthy indian country ducks. six out of 90 ducks showed positivity for dhbv dna in serum (5.4%) and only 4 out of 6 dhbv dna positive ducks answered in counter immuno electrophoresis (ciep) using specific antibody against dhbv surface antigen raised in guinea pig. the results indicate t ... | 1994 | 8088900 |
| behavioral management of specific pathogen-free rhesus macaques: group formation, reproduction, and parental competence. | breeding colonies of specific pathogen-free (spf) rhesus macaques were established to eradicate the transmission of herpesvirus simiae and several retroviruses in this species. strategies to attain this goal included the combination of large numbers of monkeys into groups, the establishment of small unimale groups, and a program using animals that were temporarily socially restricted. all methods required the establishment of new social groups from unfamiliar animals. in using these methods, we ... | 1994 | 7933968 |
| characterization of hepatitis b virus core mutants that inhibit viral replication. | we have generated and functionally characterized dominant negative core protein variants of the hepadnaviruses to determine their effects on "wild type" viral replication. plasmids expressing these constructs were introduced into hepatoma cell lines by transient transfection and effects on wild type woodchuck hepatitis virus (whv) and hepatitis b virus (hbv) replication were evaluated by southern blot analysis of purified viral core particles. whv and hbv constructs expressing a truncated core p ... | 1994 | 7975206 |
| cytosolic activation of aromatic and heterocyclic amines. inhibition by dicoumarol and enhancement in viral hepatitis b. | the aromatic amines 2-aminofluorene (2af), 2-acetylaminofluorene, and 2-aminoanthracene, and the heterocyclic amines 2-amino-3-methylimidazo[4,5-f]quinoline (iq), 2-amino-3,4-dimethylimidazo[4,5-f]quinoline, and 3-amino-1-methyl-sh-pyrido[4,3-b]indole (trp-p-2) were activated by rat liver cytosolic fractions to form mutagenic metabolites in salmonella typhimurium strains ta98, ta98nr, and ta98/1,8-dnp6. in the case of the trp-p-2, the cytosolic activation was even more potent than the microsomal ... | 1994 | 7534225 |
| woodchuck hepatitis virus surface antigen induces nitric oxide synthesis in hepatocytes: possible role in hepatocarcinogenesis. | woodchuck hepatitis virus surface antigen (whsag) stimulated hepatocytes in culture to produce nitric oxide (no.), as evidenced by the accumulation of nitrite in the medium. no. synthesis by hepatocytes was positively correlated with whsag concentration. whsag-induced no. synthesis was inhibited by ng-monomethyl-l-arginine and anti-whsag antibody. to our knowledge, this is the first demonstration of an increase in no. formation by a viral antigen. these data, when considered in the light of the ... | 1994 | 8001249 |
| therapy of chronic hepatitis b with a 6-month course of ribavirin. | ribavirin is a nucleoside analogue with broad spectrum antiviral activity that has been shown to inhibit viral replication in the woodchuck model of hepatitis b virus infection. we studied the effect of ribavirin on viral replication in 18 patients with chronic hepatitis b who were positive for hepatitis b e antigen. patients were randomized to receive a 24-week course of oral ribavirin at a dose of either 800, 1000, or 1200 mg/kg per day. all patients completed 24 weeks of treatment and an addi ... | 1994 | 7989704 |
| rapid isolation of highly productive recombinant chinese hamster ovary cell lines. | an expression system combining a unit for the expression of the gene of interest reinforced by the hepatitis b virus x transactivator and a selectable gene weakened by the insertion of an a+t-rich sequence derived from the 3'-untranslated region of the granulocyte-macrophage colony-stimulating factor mrna is described. this vector allows rapid one-step isolation of highly productive chinese hamster ovary clones. | 1994 | 7959014 |
| absence of p53 mutation at codon 249 in duck hepatocellular carcinomas from the high incidence area of qidong (china). | dietary aflatoxin and hepatitis b virus infection may play a role in generating the p53 tumor suppressor gene codon 249 hotspot mutation found in human hepatocellular carcinomas (hccs) from qidong (china) and southern africa. no data are available on the hcc site-specific mutation of the p53 gene in hepadnavirus-infected animals exposed to afb1. we have searched for the presence of p53 gene codon 249 mutations in both duck hepatitis b virus (dhbv) positive and negative hccs of domestic ducks fro ... | 1994 | 8033311 |
| woodchuck hepatitis virus surface antigen produced in vitro fails to bind polymerized woodchuck serum albumin. | using a plasmid (psws) similar to one that has been successfully used for large-scale production of hepatitis b virus (hbv) envelope protein particles (psvs) but containing the corresponding woodchuck hepatitis virus (whv) envelope gene sequences, we have stably transformed the rodent dihydrofolate reductase-deficient cell line cho dhfr-. although production of whv envelope particles in cho/psws cell lines was low, it was sufficient to test whether these particles could bind to polymerized serum ... | 1994 | 8046413 |
| apparent helper-independent infection of woodchucks by hepatitis delta virus and subsequent rescue with woodchuck hepatitis virus. | hepatitis delta virus (hdv) is a subviral agent of humans which is dependent upon hepatitis b virus as a helper for transmission. hdv can be experimentally transmitted to woodchucks by using woodchuck hepatitis virus (whv) as the helper. we used this model system to study two types of hdv infections: those of animals already chronically infected with whv and those of animals without any evidence of prior exposure to whv. at 5 to 10 days after infection with hdv, liver biopsies of these two group ... | 1994 | 8057418 |