| hazards from simian herpes viruses: reactivation of skin lesions with virus shedding. | a new simian herpes virus with biological properties similar to herpes simplex and to simian "b" virus has been used as a model system for studying virus latency in dorsal root spinal sensory ganglia. following intradermal injection, virus is present in the skin lesions and corresponding ganglia only, during the acute stage of the disease. by organ-culture techniques, latent virus was rescued from ganglia up to 2 years later. no latent virus was ever found in skin organ cultures of the primar ... | 1975 | 47078 |
| the hepatitis b virus and its dna polymerase: the prototype three-d virus. | the hepatitis b virus (hbv), the causal agent of serum hepatitis, has a diameter of 42 nm and is comprised of an outer surface coat and a 27 nm core. a unique dna-dependent dna polymerase is associated with the core of the virus. the core also houses a circular dna that contains both double-stranded and single-stranded regions. in the endogenous reaction, the dna polymerase repairs the single-stranded gaps of the viral dna. the surface protein of the virus, called hepatitis b surface antigen, co ... | 1979 | 91092 |
| serological relationship of woodchuck hepatitis virus to human hepatitis b virus. | two antigenic systems of the woodchuck hepatitis virus have been identified. the relationship between viral antigens of the woodchuck hepatitis virus and the human hepatitis b virus was determined by using immunoprecipitation, hemagglutination, and immune electron microscopy techniques. antigens found on the cores of the two viruses were cross-reactive. lack of cross-reactivity between the surface antigens of the two viruses in immunodiffusion experiments suggested that the major antigenic deter ... | 1979 | 94359 |
| transmission of hepatitis b to the rhesus monkey. studies on the humoral and cell-mediated immune response. | the susceptibility of the rhesus monkey (macaca mulatta) to hepatitis b virus was enhanced by the induction of chronic infection with plasmodium inuei. | 1978 | 101663 |
| multiple herpesvirus simiae isolation from a rhesus monkey which died of cerebral infarction. | a rhesus monkey housed in the new england regional primate research center for more than 4 yr died after an illness of 19 da. clinical signs included central nervous system involvement and ulcers on the labial mucosa. microscopically, the cause of death was established as multiple cerebral infarction. lesions characteristic of herpesvirus infections were not present in the brain nor in any other tissue; however, herpesvirus simiae was isolated from oral and anal swabs as well as from tongue and ... | 1975 | 167229 |
| recovery of herpes simiae (b virus) from both primary and latent infections in rhesus monkeys. | the suspected ability of herpes simiae (b virus) to persist in a latent form has been confirmed in rhesus monkeys. the virus was recovered from primary oral lesions of 2 young monkeys and again, 6 months after disappearance of symptoms, from cultures of gasserian ganglia taken from the same individuals. b virus was identified by its effects in vivo and in vitro and in cross neutralization tests with antisera to reference b virus and herpes simplex virus. tests showed that the same virus was pres ... | 1975 | 177038 |
| hepatitis a antigen isolated from liver and stool: immunologic comparison of antisera prepared in guinea pigs. | morphologically similar hepatitis a antigen particles (ha ag)3 have been detected in the stools of patients with type a hepatitis and in the livers of marmosets experimentally infected with hepatitis a virus. to investigate the humoral antibody responses to these antigens and to compare the immunologic properties of ha ag from these two sources, we immunized guinea pigs with either marmoset liver-derived ha ag or with human stool-derived ha ag in complete freund's adjuvant and measured their ant ... | 1976 | 182882 |
| oncogenicity of avian leukosis viruses of different subgroups and of mutants of sarcoma viruses. | leukosis viruses of seven subgroups were tested for oncogenicity in chickens susceptible to virus infection and to development of lymphoid leukosis (ll) tumors. all subgroup a viruses and the subgroup b virus tested produced a high incidence of ll and other related neoplasms. viruses of subgroup c and rav-61 of subgroup f produced a low level of ll. the rav-50 of subgroup d produced osteopetrosis. in these tests, the viruses of subgroup e and g and one virus of subgroup f were not pathogenic, po ... | 1977 | 191400 |
| comparative complement fixation and serum neutralization antibody titers to herpes simplex virus type 1 and herpesvirus simiae in macaca mulatta and humans. | the serological relationship of herpes simplex type 1 virus and herpesvirus simiae was studied. antibody titers to these viruses were determined in 163 macaca mulatta sera and 67 human sera by serum neutralization (sn) and complement fixation (cf) tests. both groups of sera were also tested by cf with envelope and capsid antigens of herpes simplex type 1. by sn, the majority of the monkeys and all of the humans had a higher titer to herpes simplex type 1 than to h. simiae. by cf, with crude anti ... | 1977 | 192762 |
| properties of the erythrocyte receptors for influenza c virus. | properties of the receptor for influenza c virus were studied. although the receptor for influenza c virus on chicken erythrocytes was destroyed by the homologous virion, neuraminidase activity could not be detected in any of the influenza c virus strains tested. the receptor activity of chicken erythrocytes for influenza c virus was diminished by formaldehyde treatment but not by periodate oxidation. there was a considerable variation in the pattern and the titer of hemagglutination of influenz ... | 1978 | 211399 |
| a virus similar to human hepatitis b virus associated with hepatitis and hepatoma in woodchucks. | particles with properties similar to those associated with human hepatitis b were found in serum from woodchucks with chronic hepatitis and hepatocellular carcinoma. it is suggested that woodchuck hepatitis virus is a second member of a novel class of viruses represented by the human hepatitis b virus. | 1978 | 212758 |
| t-lymphocyte cytotoxicity to hbsag-coated target cells in hepatitis b virus infection. | the cytotoxic effect of peripheral lymphocytes on chicken red blood cells (chrbc) coated with purified hepatitis b surface antigen (hbsag) has been studied as an in vitro parameter of cell-mediated immunity in acute and chronic infection with hepatitis b virus. using this technique, the mean cytotoxic index of lymphocytes from patients with acute hepatitis b (29.13 +/- 20.88) was significantly higher than that obtained with lymphocytes from control subjects (6.53 +/- 3.75). only 33.3% of the pat ... | 1977 | 304824 |
| [rearing and management of chimpanzees for experimental infection with hepatitis b virus (author's transl)]. | for the purpose of experimental infection with human hepatitis b virus, 14 chimpanzees (pan troglodytes) were delivered to the division of animal research, faculty of medicine, university of tokyo, tokyo. these chimps, 11 males and 3 females, born in the west africa, had been reared for two to six months. several days after delivery, they were anesthetized with ketalar in order to make clinical, bacteriological and parasitological examinations; it was found that one of them was in malnutrition, ... | 1977 | 558103 |
| [experiments for the development of a hepatitis b vaccine: immunogenicity of hbsag in guinea pigs (author's transl)]. | hepatitis b surface antigen (hbsag) was purified from human plasma by gel chromatography, isopyknic centrifugation, and zonal centrifugation. the final product had about 60% of the original activity and was essentially free from hepatitis b virus particles (hbv) and plasma proteins. treatment with formaldehyde concentrations up to 0.1% for inactivation of residual infectivity did not significantly reduce antigenicity in vitro and immunogenicity in guinea pigs. adsorption to aluminum hydroxide re ... | 1979 | 572908 |
| [biological characteristics of influenza b viruses isolated during influenza b epidemics in 1976-1977]. | comparative studies of the antigenic structure of influenza b viruses isolated in 1976-1977 and in previous years demonstrated one-way relationship of the hemagglutinin of b/76 viruses with that of b/72 viruses. antisera to new b/76 strains neutralized the hemagglutinating activity of all known reference influenza b virus strains beginning from 1972. influenza b/76 viruses were divided into two groups depending on complete or partial neutralization by antiserum b/hong kong/7/75. the study of the ... | 1978 | 749340 |
| transmission of hepatitis b to the rhesus monkey. | the rhesus monkey does provide a suitable laboratory animal model for studying hepatitis b virus and for investigating various aspects of interaction between this infectious agent and the host. this species of non-human primate, however, offers a less sensitive animal model for hepatitis b infection than the chimpanzee. | 1975 | 812744 |
| development and chimpanzee testing of a vaccine against human hepatitis b. | highly purified hepatitis b virus surface antigen (australia antigen) purified by physical and chemical procedures from infected human plasma was used to prepare hepatitis b vaccine. the purified antigen was treated with formalin and the vaccine was tested exhaustively for safety by ordinary procedures and additionally in marmosets (for live hepatitis b virus). the vaccine was highly potent, inducing antibody in guinea pigs, grivet monkeys, and chimpanzees given three doses of vaccine containing ... | 1976 | 817293 |
| vaccine against human hepatitis b. | a highly purified and inactivated vaccine was made of hepatitis b virus surface antigen. the vaccine was tested exhaustively for safety by ordinary procedures and additionally in chimpanzees and marmosets. it was highly potent and induced antibody in guinea pigs, grivet monkeys, and chimpanzees after three doses of vaccine were given subcutaneously. chimpanzees given three doses of vaccine were protected against challenge with 1,000 chimpanzee-infectious doses of live human hepatitis b virus giv ... | 1976 | 819667 |
| viral hepatitis, type b, in experimental animals. | evidence of natural infection with hepatitis b virus (hbv) in chimpanzees was followed by demonstration that this species provides a highly sensitive animal model system for experimental type b hepatitis. with rare exceptions, inoculation of sero-negative chimps with materials containing infectious hbv produces serologic evidence of infection including appearance of circulating hepatitis b surface antigen (hbs ag) and subsequently development of antibody to hbs ag and hepatitis b core antigen. s ... | 1975 | 1181931 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| animal models of hepatocellular carcinoma: hepadnavirus-induced liver cancer in woodchucks. | woodchuck hepatitis virus (whv), a member of the hepadnaviridae, is closely related to hepatitis-b virus (hbv) in its virus structure, genetic organization, and mechanism of replication. as with hbv in man, persistent whv infection is common in natural woodchuck populations and is associated with chronic hepatitis and hepatocellular carcinoma (hcc). experimental studies have established that whv causes hcc in woodchucks. chronic whv carriage as an outcome of experimental infection is a function ... | 1991 | 1751825 |
| [hepatitis b virus and hepatocellular carcinoma]. | hepatocellular carcinoma in woodchuck were characterized for woodchuck hepatitis virus integration nea c-myc oncogene. in one tumor, viral integration resulted in overexpression of a c-myc viral cotranscript. in a second tumor, viral insertion, 600 bp upstream of c-myc exon 1, was associated with increased levels of normal c-myc mrna. these results demonstrate that integration of woodchuck hepatitis virus near a proto-oncogene can contribute to the genesis of liver tumors. from a comparison of a ... | 1991 | 1772242 |
| 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 |
| 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 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| fatal herpesvirus simiae (b virus) infection in a patas monkey (erythrocebus patas). | | 1990 | 1965586 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| trans-complementation of the c gene of human and the p gene of woodchuck hepadnaviruses. | a 5 bp insertion was introduced into the bsteii site at nucleotide 2815 in dna of hepatitis b virus (hbv) and a mutant hbv genome was produced, which coded for envelope and core proteins, but not for dna polymerase, due to a frameshift. cultured hepatoma cells (hepg2) were simultaneously transfected with a plasmid harbouring a tandem dimer of the mutant hbv dna and another plasmid harbouring a tandem dimer of dna of woodchuck hepatitis virus or duck hepatitis b virus. the replication of mutant h ... | 1990 | 2157804 |
| hepatitis b virus and primary hepatocellular carcinoma: treatment of hbv carriers with phyllanthus amarus. | a viricide capable of eliminating hepatitis b virus (hbv) from chronic carriers should, theoretically, decrease the risk of primary hepatocellular carcinoma. extracts of phyllanthus amarus have been shown to inhibit the dna polymerase of hbv and woodchuck hepatitis virus (whv) in vitro. three of four recently infected whv carriers treated i.p. with p. amarus extract lost whv, animals infected for greater than or equal to 3 months showed a decrease in virus levels. preliminary results in human ca ... | 1990 | 2158192 |
| 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 |
| 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 |
| progress report on the charles river breeding laboratories' free-ranging rhesus monkey breeding colony on key lois, florida. | the nucleus of a breeding colony of free-ranging rhesus monkeys (macaca mulatta) free from tuberculosis, herpes-b virus, shigellosis, and salmonellosis has been established on key lois, florida, usa. standardized procedures for trapping, quarantine, and shipping from the wild in india to the island have been established. the monkeys seem to have adapted well to the florida keys' climate. reproduction has proceeded according to expectations, and social groups have been formed with continual restr ... | 1976 | 1271747 |
| hepatitis b core antigen and antibody. | two distinct antigen-antibody systems are associated with the hepatitis b virus: the hepatitis b surface antigen (hbsag, australia antigen) and antibody (anti-hbs) and the recently characterized hepatitis b core antigen (hbcag) and antibody (anti-hbc, anti-core). hbsag is found in the serum of patients acutely or chronically infected with the hepatitis b virus (hbv) and is represented on electron microscopy of such serum as 20 nm spherical and tubular structures and as the surface component of t ... | 1975 | 1204955 |
| transmission experiments with hepatitis b surface antigen and the common bedbug (cimex lectularius l). | hepatitis b surface antigen (hbsag)-positive blood meals were fed to a colony of the common bedbug (cimex lectularius l) in a series of 5 experiments. antigen persisted in the bugs for at least 7 1/2 weeks, but was undetectable after 18 weeks. trans-stadial transmission was demonstrated through one moult only, and transovarial transmission did not occur. antigen was successfully transmitted by adult bugs into 3 out of 35 canisters of hbsag-negative blood. antibody of hbsag was detected in the se ... | 1979 | 573506 |
| partial amino acid sequence of two major component polypeptides of hepatitis b surface antigen. | determination of the amino acid sequence of the immunogenic polypeptides of hepatitis b surface antigen may not only permit molecular localization of the distinct determinants a, d, and y but may also lead to the synthesis of a hapten useful in prophylactic immunization against hepatitis b virus infection. for this purpose, purified monotypic hepatitis b surface antigen of adw subtype was resolved into equal amounts of two major polypeptides (22,000 and 28,000 daltons) and up to six other minor ... | 1977 | 266193 |
| integration of hepatitis virus dna near c-myc in woodchuck hepatocellular carcinoma. | a total of 33 hepatocellular carcinomas, induced in woodchucks by chronic infection with woodchuck hepatitis virus (whv), a virus closely related to the human hepatitis b virus, were analyzed for the state of viral dna, the expression of viral genes and of different cellular proto-oncogenes. low levels of viral replication and presence of integrated viral forms including sequences of the enhancer element, appeared as a general rule in these tumors. enhanced expression of one or more of the nucle ... | 1990 | 2172071 |
| hepadnaviruses, their infections and hepatocellular carcinoma. | ten years ago hepatitis b virus (hbv) was thought to be a unique virus, not included in any known family of viruses. following the discovery of a number of hbv-like viruses that infect birds and mammals, the existence of a new family known as hepadnaviridae has been confirmed. hepadnaviruses are small hepatotropic viruses that have a characteristic partially double stranded genome, exhibit a narrow host range and replicate by reverse transcription. the family currently comprises six viruses of w ... | 1990 | 2178194 |
| 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 |
| classification of porcine enteroviruses by antigenic analysis and cytopathic effects in tissue culture: description of 3 new serotypes. | porcine enteroviruses isolated in the united kingdom between 1972 and 1976 were compared with the 8 serotypes previously described and with human coxsackie b virus types 1 to 6 for ability to grow in different cell lines. this allowed the classification of all strains into 3 broad groups according to type of cytopathic effect in ibrs-2 cells and further subdivision on the basis of production of cytopathic effect in bhk 21, hela and vero cells. none of the porcine enterovirus strains was neutrali ... | 1979 | 229804 |
| viral type a and type b hepatitis: morphology, biology, immunology and epidemiology--a review. | viral hepatitis is one of the most serious infectious diseases in the united states and is of great concern to the public health agencies, hospitals and research laboratories. progress in our knowledge of this disease has been based on cooperation between specialists in many diverse scientific disciplines employing sophisticated scientific instruments and technics. close cooperation between clinical pathologists and clinicians is of great importance in diagnosis. biologic, immunologic, epidemiol ... | 1976 | 218439 |
| 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 |
| experimental carcinoma of liver in macaque monkeys exposed to diethylnitrosamine and hepatitis b virus. | the effects of treatments with diethylnitrosamine (dena) and hepatitis b virus (hbv) on macaque monkeys were investigated by virus serology and by light and electron microscopy. the experimental groups comprised 43 newborn or juvenile cynomolgus and rhesus monkeys of both sexes. hbv neither had a carcinogenic effect nor increased the oncogenic effect of dena. however, hbv given to juvenile primates before treatment with dena resulted in subsequent gross and microscopic alterations consistent wit ... | 1977 | 198564 |
| multiple testing for the detection of b virus antibody in specially handled rhesus monkeys after capture from virgin trapping grounds. | eight groups of rhesus monkeys totaling over 1,000 animals were captured in the virgin trapping grounds of jammu and kashmir, india. individual caging and special handling technics were utilized to prevent cross-contamination during capture, holding, and subsequent shipment to quarantine facilities in the united states. immediately following the arrival of the monkeys, 5 consecutive blood samples were obtained at approximately 2-wk intervals, and the sera were rested for neutralizing antibody ag ... | 1976 | 177807 |
| the isolation of monkey b virus (herpesvirus simiae) from the trigeminal ganglia of a healthy seropositive rhesus monkey. | | 1975 | 169266 |
| 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 |
| immunochemical and oligonucleotide fingerprint analyses of venezuelan equine encephalomyelitis complex viruses. | rna oligonucleotide fingerprint analyses indicate that the genome rna obtained from trinidad donkey (trd) venezuelan equine encephalomyelitis (vee) virus serotype i a, its vaccine strain derivative tc-83, and the vee i b virus isolate ptf-39, have almost identical patterns of characteristic ribonuclease t1 resistant oligonucleotides. the tc-83 strain and the i b isolate can, on the basis of these analyses, be considered as variants of the trd virus and categorized as i ab serotypes. comparisons ... | 1979 | 90115 |
| antigens of hepatitis b virus: failure to detect hbeag on the surfaces of hbsag forms. | the particulate forms of hbsag were analysed for the presence of hbeag on their surfaces. by immunodiffusion analysis, anti-hbe did not form precipitin bands with the purified forms of hbsag and hyperimmune guinea pig antisera to these forms did not react with hbeag. lines of non-identity were observed between the hbeag determinants (e1 and e2) and the dane particles and filaments isolated from an hbeag-positive serum. finally, anti-hbe failed to precipitate the polymerase-positive subpopulation ... | 1978 | 75946 |
| immune complexes of hepatitis b surface antigen in the pathogenesis of periarteritis nodosa. a study of seven necropsy cases. | in 7 unselected necropsy cases of clinically diagnosed periarteritis nodosa, the detection of hepatitis b surface antigen (hbsag) and hepatitis b core antigen (hbcag) in the cytoplasm and nuclei of hepatocytes indicated an ongoing infection with hepititis b virus (hbv). in all these cases histologic changes found in the liver varied from "minimal" to chronic aggressive hepatitis. in all the cases, deposits of hbsag, immunoglobulins, beta1c-globulin and c1q were detected in vascular lesions. that ... | 1978 | 24342 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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: 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 |
| [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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |