| activation of the n-myc2 oncogene by woodchuck hepatitis virus integration in the linked downstream b3n locus in woodchuck hepatocellular carcinoma. | in the woodchuck hepatitis virus (whv)/woodchuck model for hepatitis b virus-induced hepatocellular carcinoma, frequent activation of n-myc oncogenes by whv integration has been firmly established. n-myc2, the most frequently affected gene, was reported to be activated by whv insertion either in the proximity of the gene or in a distant uncoding locus, win. we previously reported that a whv integration cloned from a liver tumor was located in a chromosomal locus already described by others as th ... | 1999 | 10329558 |
| b-virus specific-pathogen-free breeding colonies of macaques (macaca mulatta): retrospective study of seven years of testing. | national institutes of health's division of comparative medicine has sponsored a multi-institutional program for the establishment of specific-pathogen-free (spf) macaque colonies. b virus (herpesvirus simiae, cercopithecine herpesvirus type 1) has been targeted in this surveillance. participating institutions have established individual timetables for frequency of testing and types of monitoring and husbandry techniques, all with the common goal of producing pathogen-free monkeys for research. ... | 1999 | 10331543 |
| [experimental study of residual virulence of viral vaccine strains]. | residual virulence of three vaccinia strains: neurovaccine, l-ivp, and its recombinant revacs-b expressing hbs and pres2 antigens of hepatitis b virus is compared. insertion of hbs and pres2 antigens of hepatitis b virus in the genome of vaccinia virus strain l-ivp decreases its residual virulence and leads to a benign course of vaccinal reaction involving no deaths of rabbits, cotton rats, or guinea pigs. we may expect that recombinant vaccine revacs b based on l-ivp strain will cause no postva ... | 1999 | 10358902 |
| the expression of insulin-like growth factor ii, hepatitis b virus x antigen and p21 in experimental hepatocarcinogenesis in tree shrews. | the purpose of this paper was to study the mechanism of synergistic effect in hepatocarcinogenesis induced by hepatitis b virus (hbv) infection and aflatoxin b1 (afb1) intake. immunohistochemical staining was used in formalin-fixed, paraffin-embedded sections of cancer and liver tissues. the incidence of hepatocellular carcinomas (hccs) was 52.9% in experimental tree shrews that received both hbv and afb1. it was significantly higher than that of animals exposed to hbv (11.1%, group b), or (afb1 ... | 1999 | 10374027 |
| synergistic effect of hepatitis b virus and aflatoxin b1 in hepatocarcinogenesis in tree shrews. | an animal experiment with tree shrews was performed to detect the synergistic effects of hepatitis b virus (hbv) infection and dietary aflatoxin b1 (afb1) in hepatocarcinogenesis. adult healthy tree shrews (tupaia belangeri chinensis) were divided into four groups: group a (hbv + afb1)--animals were infected with human hbv serum at first, then fed afb1 diluted with milk, 150 ug/kg.bw/day, 6 days/week for 105 weeks. group b (hbv)--animals were infected with human hbv as group a, but no afb1 treat ... | 1999 | 10374028 |
| threat to humans from virus infections of non-human primates. | several hundred distinct non human primate species are recognised, and they are likely to harbour a similar range of viruses to humans. simians such as cynomolgus and rhesus macaques, african green monkeys, and marmosets are widely used for biomedical research, but despite this extensive close contact very few simian viruses have been shown to pose a threat of infection or illness to humans. herpesvirus simiae is the best recognised zoonotic hazard of simians. it is an alphaherpes virus of asiat ... | 1997 | 10398488 |
| persistence of infectious hepadnavirus in the offspring of woodchuck mothers recovered from viral hepatitis. | mother-to-child transmission is an important route for hepatitis b virus (hbv) dissemination. it has been established that hbv traces persist for years after complete clinical recovery from hepatitis b. similarly, resolution of hepatitis caused by hbv-related woodchuck hepatitis virus (whv) is followed by occult lifelong carriage of pathogenic virus. in this study, we documented that whv persisting after termination of acute hepatitis is transmittable to newborns as an asymptomatic long-term inf ... | 1999 | 10411550 |
| perspectives for the treatment of hepatitis b virus infections. | primarily resulting as a spin-off of the search for effective anti-hsv or anti-hiv agents, several compounds have been identified as effective and promising candidate anti-hbv drugs, i.e. famciclovir (penciclovir), bms-200475, lamivudine (3tc), (-)ftc, l(-)fd4c, l-fmau, dapd (dxg), bis(pom)-pmea and bis(poc)-pmpa. they all inhibit hbv replication in hep g2 2.2.15 at concentrations that are well below the cytotoxicity threshold. all these nucleoside analogues require three phosphorylation steps t ... | 1999 | 10418752 |
| a new group of hepadnaviruses naturally infecting orangutans (pongo pygmaeus). | a high prevalence (42.6%) of hepatitis b virus (hbv) infection was suspected in 195 formerly captive orangutans due to a large number of serum samples which cross-reacted with human hbv antigens. it was assumed that such viral infections were contracted from humans during captivity. however, two wild orangutans were identified which were hbv surface antigen positive, indicating that hbv or related viruses may be occurring naturally in the orangutan populations. sequence analyses of seven isolate ... | 1999 | 10438880 |
| fusogenic activity of hepadnavirus peptides corresponding to sequences downstream of the putative cleavage site. | sequence homology between the amino-terminal region of the s protein of hepatitis b virus (hbv) and known fusion peptides from retroviruses and paramyxoviruses led us to propose that this region might be equally involved in the initial infective steps of hepadnaviruses. in fact, we showed that a synthetic peptide corresponding to the n-terminus region of the s protein of hbv had membrane-interacting properties and was able to induce liposome fusion adopting an extended (beta-sheet) conformation ... | 1999 | 10441561 |
| new chimaeric hepatitis b virus core particles carrying hantavirus (serotype puumala) epitopes: immunogenicity and protection against virus challenge. | virus-like particles generated by the heterologous expression of virus structural proteins are able to potentiate the immunogenicity of foreign epitopes presented on their surface. in recent years epitopes of various origin have been inserted into the core antigen of hepatitis b virus (hbv) allowing the formation of chimaeric hbv core particles. chimaeric core particles carrying the 45 n-terminal amino acids of the puumala hantavirus nucleocapsid protein induced protective immunity in bank voles ... | 1999 | 10486924 |
| identification and expression of glycine decarboxylase (p120) as a duck hepatitis b virus pre-s envelope-binding protein. | a 120-kilodalton protein (p120) was identified in the duck liver that binds to several truncated versions of duck hepatitis b virus (dhbv) pre-s envelope protein, suggesting p120 may serve as a dhbv co-receptor. the amino acid sequences of tryptic peptides from purified p120 were found to be the duck p protein of the glycine decarboxylase complex (dgd). dgd cdna cloning revealed extensive protein conservation with the chicken homologue except for several insertions in the n-terminal leader seque ... | 1999 | 10488106 |
| a new avian hepadnavirus infecting snow geese (anser caerulescens) produces a significant fraction of virions containing single-stranded dna. | we describe the identification and functional analysis of an evolutionary distinct new avian hepadnavirus. infection of snow geese (anser caerulescens) with a duck hepatitis b virus (dhbv)-related virus, designated sghbv, was demonstrated by detection of envelope proteins in sera with anti-dhbv pres and s antibodies. comparative sequence analysis of the pcr-amplified sghbv genomes revealed unique sghbv sequence features compared with other avian hepadnaviruses. unlike dhbv, sghbv shows an open r ... | 1999 | 10489339 |
| evaluation of immune responses to inactivated influenza vaccines prepared in embryonated chicken eggs and mdck cells in a mouse model. | this study was initiated with the isolation of influenza a and b viruses from clinical throat swabs in both fertile chicken eggs (egg) and mdck cells, which were used in subsequent vaccine production in the above two hosts. on the basis of haemagglutination-inhibiting (hi) tests, immune mouse sera from mice vaccinated with mdck cell-derived vaccines revealed antigenic similarities among h3n2 or b viruses isolated in mdck cells or eggs. similarly, antiserum prepared by immunization with egg-deriv ... | 1999 | 10494959 |
| unraveling hepatitis b virus infection of mice and men (and woodchucks and ducks) | | 1999 | 10502809 |
| hepatitis b virus x protein: structure, function and biology. | the x gene is conserved among mammalian hepadnaviruses and the x protein, px, is essential for viral propagation at least in the woodchuck. during the last decade, efforts have centered on elucidating the oncogenic role of px in hepatitis b virus infection. the accumulating knowledge on px indicates that it is a multifunctional regulatory protein which modulates many host functions by communicating directly or indirectly with a variety of host targets as is the case for many viral regulatory pro ... | 1999 | 10516464 |
| echoviruses and coxsackie b viruses that use human decay-accelerating factor (daf) as a receptor do not bind the rodent analogues of daf. | many serotypes of echovirus (ev) and coxsackie b virus (cbv) bind human decay-accelerating factor (daf) and use it as a receptor for infection. analogues for daf have been isolated from mice and rats and characterized; these analogues have amino acid identities to human daf of approximately 60%. ev serotypes 3, 6', 7, 11-13, and 29 and cbv serotypes 1, 3, and 5 caused hemagglutination of human erythrocytes but not rat or mouse erythrocytes, suggesting failure to bind rodent daf. to confirm this ... | 2000 | 10608785 |
| effects of age and viral determinants on chronicity as an outcome of experimental woodchuck hepatitis virus infection. | acute hepadnavirus infections either resolve or progress to chronicity. factors that influence chronicity as an outcome of hepatitis b virus (hbv) infection in humans can be studied experimentally in the woodchuck model. accordingly, several woodchuck hepatitis virus (whv) inocula were characterized. representative inocula had high titers of infectious virus (approximately 10(7.7)-10(9.5) woodchuck 50% infectious doses per milliliter [wid(50%)/ml] by subcutaneous inoculation), with 1 wid(50%) ra ... | 2000 | 10613745 |
| phyllanthus orbicularis aqueous extract: cytotoxic, genotoxic, and antimutagenic effects in the cho cell line. | the present work evaluates the cytotoxic, genotoxic, and antimutagenic effects of phyllanthus orbicularis (plant of genus phyllantus) aqueous extract in chinese hamster ovary (cho) cells. p. orbicularis aqueous extracts are used in cuban traditional medicine for their antiviral activity against hepatitis b virus and a and b flu virus. the cytotoxicity of the extract was tested by means of colony-forming ability and growth-inhibition assays as well as by measuring the mitotic index. apoptosis ind ... | 1999 | 10620480 |
| apoptosis and regeneration of hepatocytes during recovery from transient hepadnavirus infections. | it is well known that hepatitis b virus infections can be transient or chronic, but the basis for this dichotomy is not known. to gain insight into the mechanism responsible for the clearance of hepadnavirus infections, we have performed a molecular and histologic analysis of liver tissues obtained from transiently infected woodchucks during the critical phase of the recovery period. we found as expected that clearance from transient infections occurred subsequent to the appearance of cd4(+) and ... | 2000 | 10627561 |
| full-genome sequence analyses of hepatitis b virus (hbv) strains recovered from chimpanzees infected in the wild: implications for an origin of hbv. | hepatitis b virus (hbv) belongs to the genus orthohepadnavirus of the family hepadnaviridae. having been found in various animals (duck, heron, woodchuck, ground squirrel, and primates), hepadnaviruses must have undergone a long history of evolution and may comprise more members than currently recognized. chimpanzees may also have their own hepadnavirus, even if it might be very close to hbv. we analyzed hbv-like sequences from three chimpanzees (pan troglodytes) that were most likely infected d ... | 2000 | 10648183 |
| kemri hep-cell ii hepatitis b surface antigen screening kit. | kenya is a high hepatitis b virus (hbv) endemic zone. prevention of hbv transmission by transfusing safe blood is necessary. kits for screening hepatitis b surface antigen (hbsag) are usually imported and are expensive. hence it has been difficult to screen donated and patient blood samples all over kenya. | 1999 | 10685326 |
| immune responses to duck hepatitis b virus infection. | the duck hepatitis b virus (dhbv) was the first hepatitis b virus identified from an avian host. it is a member of the hepadnaviridae family of viruses. all members of this family display similar genomic organization and replication strategies and cause species-specific infections that result in either transient (acute) or persistent infection. hepadnavirus infection occurs primarily in hepatocytes in the liver with release of infectious virions and non-infectious 'empty' surface antigen particl ... | 2000 | 10717294 |
| woodchuck lymphotoxin-alpha, -beta and tumor necrosis factor genes: structure, characterization and biological activity. | we cloned and characterized the woodchuck tumor necrosis factor (tnf) and lymphotoxin-alpha, -beta (lt-alpha, -beta) cdnas, genes and proteins to facilitate study of the functions of these cytokines during the course of woodchuck hepatitis virus (whv) infection. woodchuck cdna and genomic dna libraries were screened with woodchuck-specific dna probes to isolate the cdna and gene clones for tnf, lt-alpha and lt-beta. the cdnas for woodchuck tnf, lt-alpha and lt-beta code for proteins of 233, 205 ... | 2000 | 10721723 |
| preclinical investigation of l-fmau as an anti-hepatitis b virus agent. | preclinical aspects of a potent anti-hepatitis b virus (hbv) l-nucleoside, 1-(2-fluoro-5-methyl-beta-l-arabino-furanosyl)uracil (l-fmau) are described. l-fmau was prepared from l-ribose derivatives via either l-xylose or l-arabinose. l-fmau shows potent antiviral activity against hepatitis b virus (ec50 5.0 microm in h1 cells) with high selectivity in vitro. l-fmau is not incorporated into mitochondrial dna and no significant lactic acid production was observed in vitro. l-fmau is phosphorylated ... | 1998 | 10726061 |
| detection of hepatitis b virus infection in wild-born chimpanzees (pan troglodytes verus): phylogenetic relationships with human and other primate genotypes. | infection with hepatitis b virus (hbv) was detected by serological testing for hbv surface antigen and by pcr assay for hbv dna in serum samples from two common chimpanzees (pan troglodytes subsp. verus) born in west africa. the complete genome sequences obtained by nucleotide sequencing of overlapping dna fragments amplified by pcr were compared with hbv variants recovered from other primates and with human genotypes a to f. both chimpanzee sequences were 3, 182 nucleotides in length, and the s ... | 2000 | 10756039 |
| enhanced antiviral benefit of combination therapy with lamivudine and famciclovir against whv replication in chronic whv carrier woodchucks. | cell culture studies in our laboratory and others have previously demonstrated synergistic antiviral activity for combinations of 3tc (lamivudine) and penciclovir against hepatitis b virus (hbv) replication and the duck hepatitis b virus (dhbv). based on these results, a study was designed to determine if an enhanced antiviral effect with combinations of 3tc and famciclovir (fcv, oral prodrug of penciclovir) could be demonstrated in vivo using the woodchuck hepatitis virus (whv)/woodchuck experi ... | 2000 | 10774587 |
| posttranscriptional inhibition of class i major histocompatibility complex presentation on hepatocytes and lymphoid cells in chronic woodchuck hepatitis virus infection. | woodchuck hepatitis virus (whv), similar to human hepatitis b virus, causes acute liver inflammation that can progress to chronic hepatitis and hepatocellular carcinoma. whv also invades cells of the host lymphatic system, where it persists for life. we report here that acute and chronic hepadnavirus hepatitis is characterized by a profound difference in the expression of class i major histocompatibility complex (mhc) molecules on the surface of infected hepatocytes and, notably, lymphoid cells. ... | 2000 | 10775584 |
| treatment of chronic woodchuck hepatitis virus infection in the eastern woodchuck (marmota monax) with nucleoside analogues is predictive of therapy for chronic hepatitis b virus infection in humans. | the woodchuck hepatitis virus (whv) and its natural host, the eastern woodchuck (marmota monax), have been established as a model of hepatitis b virus (hbv)-induced disease. several published studies have used this experimental animal model system to demonstrate potential antiviral therapies for chronic hbv infections. however, there has been little comparative information available on compounds used in clinical anti-hbv studies in whv-infected woodchucks, thereby making interpretations of the p ... | 2000 | 10796894 |
| susceptibility of chacma baboons (papio ursinus orientalis) to infection by hepatitis b virus. | because baboons are being considered as a source of xenografts for human liver transplantation in patients with hepatitis b virus- (hbv) induced cirrhosis to forestall infection of the graft by the virus, we undertook a study to ascertain if baboons are resistant to hbv infection. | 2000 | 10798766 |
| reduction of aflatoxin b(1) adduct biomarkers by oltipraz in the tree shrew (tupaia belangeri chinensis). | the risk of liver cancer is greatest in people both infected with hepatitis b virus (hbv) and highly exposed to aflatoxin b(1) (afb(1)). the tree shrew (tupaia belangeri chinensis) is a unique species that can be infected with human hbv, is susceptible to afb(1)-induced liver cancer, and shows a synergistic interaction between hbv and afb(1) for liver cancer. in this regard, the tree shrew may be useful for evaluating experimental chemoprevention strategies relevant to high-risk human population ... | 2000 | 10799742 |
| occult persistence and lymphotropism of hepadnaviral infection: insights from the woodchuck viral hepatitis model. | hepatitis b virus (hbv) is a major human pathogen that causes chronic infection and life-threatening liver diseases in millions of individuals. while pathological and epidemiological consequences of clinically evident hbv infections are well recognized, there is no similar knowledge on an asymptomatic, silently progressing virus persistence. contrary to previous opinion, current evidence indicates that a serologically undetectable (occult) hbv carriage is a common outcome of recovery from sympto ... | 2000 | 10807510 |
| influenza b virus in seals. | influenza b virus is a human pathogen whose origin and possible reservoir in nature are not known. an influenza b virus was isolated from a naturally infected harbor seal (phoca vitulina) and was found to be infectious to seal kidney cells in vitro. sequence analyses and serology indicated that influenza virus b/seal/netherlands/1/99 is closely related to strains that circulated in humans 4 to 5 years earlier. retrospective analyses of sera collected from 971 seals showed a prevalence of antibod ... | 2000 | 10807575 |
| effect of oral administration of emtricitabine on woodchuck hepatitis virus replication in chronically infected woodchucks. | emtricitabine [(-)ftc] [(-)-beta-2', 3'-dideoxy-5-fluoro-3'-thiacytidine] has been shown to be an effective inhibitor of hepatitis b virus (hbv) in cell culture, with a potency and selectivity that are essentially identical to those of lamivudine. the antiviral activity of oral administration of (-)ftc against whv replication in chronically infected woodchucks, an established and predictive model for antiviral therapy against hbv, was examined in a placebo-controlled study. (-)ftc significantly ... | 2000 | 10817750 |
| antiviral activities of oral 1-o-hexadecylpropanediol-3-phosphoacyclovir and acyclovir in woodchucks with chronic woodchuck hepatitis virus infection. | acyclovir triphosphate is a potent inhibitor of hepatitis b virus dna polymerase, but acyclovir treatment provides no benefit in patients with hepatitis b virus infection. this is due in part to the fact that hepatitis b virus, unlike herpes simplex virus, does not code for a viral thymidine kinase which catalyzes the initial phosphorylation of acyclovir. we synthesized 1-o-octadecyl-sn-glycero-3-phospho (3-p)-acyclovir and found that it was highly active in reducing hepatitis b virus replicatio ... | 2000 | 10858362 |
| mutations in the p53 tumor suppressor gene in tree shrew hepatocellular carcinoma associated with hepatitis b virus infection and intake of aflatoxin b1. | infection with hepadnaviruses and exposure to aflatoxin b1 (afb1) are considered to be major risk factors in the development of hepatocellular carcinoma (hcc) in humans. a high rate of p53 mutations at codon 249 has been reported in these tumors. the tree shrew (tupaia belangeri chinensis) is a useful animal model for the development of hcc after human hepatitis b virus (hbv) infection or afb1 treatment. therefore, it was of particular interest to determine whether the p53 gene in tree shrew hcc ... | 2000 | 10863098 |
| increased hepatocyte turnover and inhibition of woodchuck hepatitis b virus replication by adefovir in vitro do not lead to reduction of the closed circular dna. | the aim of this study was to evaluate the inhibitory effect of the nucleotide analogue adefovir on woodchuck hepatitis b virus (whv) replication and, in particular, to determine whether the pool of covalently closed circular dna (cccdna) could be reduced by adefovir treatment in primary cultures of woodchuck hepatocytes isolated from a chronic carrier. strong reduction of whv-dna synthesis (90%) and secretion (up to 98%) was observed with all 3 doses of adefovir used (1, 10, and 100 micromol/l), ... | 2000 | 10869302 |
| herpes b-virus specific-pathogen-free breeding colonies of macaques (macaca mulatta): diagnostic testing before and after elimination of the infection. | the national institutes of health's (nih) national center for research resources' (ncrr) division of comparative medicine has funded the establishment of specific pathogen-free (spf) captive macaque colonies. herpes b-virus (herpesvirus simiae, cercopithecine herpesvirus type 1) has been targeted for elimination. late seroconversion presents the greatest threat to the integrity of spf colonies. the purpose of the study reported here was to evaluate that threat through detailed investigation of t ... | 2000 | 10894500 |
| the collagen repeat sequence is a determinant of the degree of herpesvirus saimiri stp transforming activity. | herpesvirus saimiri (hvs) is divided into three subgroups, a, b, and c, based on sequence divergence at the left end of genomic dna in which the saimiri transforming protein (stp) resides. subgroup a and c strains transform primary common marmoset lymphocytes to interleukin-2-independent growth, whereas subgroup b strains do not. to investigate the nononcogenic phenotype of the subgroup b viruses, stp genes from seven subgroup b virus isolates were cloned and sequenced. consistent with the lack ... | 2000 | 10933720 |
| enhanced antiviral benefit of combination therapy with lamivudine and alpha interferon against whv replication in chronic carrier woodchucks. | cell culture studies in our laboratory previously demonstrated synergistic antiviral activity for the combinations of lamivudine and a novel recombinant hybrid human alpha b/d interferon (rhu alpha b/d ifn) against hepatitis b virus (hbv) replication. based on these results, a study was designed to determine if an enhanced antiviral effect with this drug combination could be demonstrated in vivo using the woodchuck hepatitis virus (whv)/woodchuck experimental model of chronic hbv infection. both ... | 2000 | 10971862 |
| correct binding of viral x protein to uvddb-p127 cellular protein is critical for efficient infection by hepatitis b viruses. | a fully effective treatment of chronic human hepatitis b virus (hbv) infection is still missing and hbv remains the first etiological agent of liver cancer. although the viral regulatory x protein is essential for infection, its mode of action remains obscure, due the lack of an in vitro infection system. in the accompanying study, we showed the functional importance of interaction between x and the host protein uvddb-p127, in the transactivation and apoptotic properties of the viral protein. he ... | 2000 | 10980618 |
| limitations to replication of hepatitis delta virus in avian cells. | human hepatitis delta virus (hdv) is a natural subviral agent that uses hepatitis b virus as a helper. experimentally, hdv can be made to replicate in woodchucks, using woodchuck hepatitis b virus as a helper virus. also, independent of such helper activity, replication of the hdv rna genome can be achieved in many mammalian cells. in this study we examined whether such replication could also be achieved in avian cells. we used cotransfection strategies and initially found no detectable genome r ... | 2000 | 10982328 |
| high-level synthesis of human prolactin in chinese-hamster ovary cells. | two eukaryotic human prolactin (hprl) expression vectors, based on a selectable dihydrofolate reductase (dhfr) marker, were used to transfect dhfr(-) chinese- hamster ovary (cho) cells. one vector, p658-hprl, contains the hepatitis-b virus-x cdna coding for a viral transactivator and sequences mediating dhfr mrna degradation. the other, peddc-hprl, carries the encephalomyocarditis virus leader sequence coupled to hprl cdna to provide high-level protein expression, possibly via a mechanism of int ... | 2000 | 11001873 |
| 48-mer synthetic peptide analogue of the hepatitis b virus "a" determinant induces an anti-hbs antibody response after a single injection. | an extended (48 amino acid) synthetic peptide analogue of the hepatitus b virus (hbv) s protein (hbsag) 'a' determinant has been produced by using 9-fluorenylmethoxycarbonyl (fmoc) chemistry and a low substitution polystyrene resin as the solid phase support. this peptide (s121/48) elicited a sustained anti-peptide antibody response in balb/c (h-2(d)) mice when immunised with freund's complete adjuvant (fca). cross-reactive, anti-hbs antibodies were induced, directed against a significant propor ... | 2000 | 11002244 |
| temporal pathogenesis of experimental neonatal woodchuck hepatitis virus infection: increased initial viral load and decreased severity of acute hepatitis during the development of chronic viral infection. | acute hepatitis b virus (hbv) infections either resolve or progress to chronicity. identification of early deviations in host-virus responses associated with these outcomes can further differentiate cause-effect mechanisms that initiate and maintain chronicity. neonatal woodchucks were infected experimentally with the woodchuck hepatitis virus (whv) at 3 days of age. at 8 or 14 weeks of age (i.e. , the early- or mid-acute stage of infection), whole blood and large surgical biopsies of the liver ... | 2000 | 11003627 |
| identification of five different patr class i molecules that bind hla supertype peptides and definition of their peptide binding motifs. | we have sequenced the pan troglodytes class i (patr) molecules from three common chimpanzees and expressed them as single molecules in a class i-deficient cell line. these lines were utilized to obtain purified class i molecules to define the peptide binding motifs associated with five different patr molecules. based on these experiments, as well as analysis of the predicted structure of the b and f polymorphic mhc pockets, we classified five patr molecules (patr-a*0101, patr-b*0901, patr-b*0701 ... | 2000 | 11035079 |
| nucleosomes are major t and b cell autoantigens in systemic lupus erythematosus. | double-stranded dna (dsdna) is a well-known target of autoantibodies in systemic lupus erythematosus (sle). the majority of these autoantibodies are of the igg isotype and show affinity maturation, both of which are known hallmarks of t cell help. t cell responses to autoantigens, including dna, have been reported only incidentally in sle patients. nevertheless, in murine sle, naked dna and complexed dna (nucleosomes) are known to be recognized by t cells. this study aimed to characterize the an ... | 2000 | 11037891 |
| puumala (puu) hantavirus strain differences and insertion positions in the hepatitis b virus core antigen influence b-cell immunogenicity and protective potential of core-derived particles. | hepatitis b virus (hbv) core-derived chimeric particles carrying a puumala (puu) hantavirus (strain vranica/hällnäs) nucleocapsid (n) protein sequence (aa 1-45), alternatively inserted at three distinct positions (n-, c-terminus, or the internal region), and mosaic particles consisting of hbv core as well as core/puu (vranica/hällnäs) n (aa 1-45) readthrough protein were generated. chimeric particles carrying the insert at the n-terminus or the internal region of core induced some protective imm ... | 2000 | 11040127 |
| naturally occurring woodchuck hepatitis virus (whv) deletion mutants in chronically whv-infected woodchucks. | deletion mutants of hepatitis b virus (hbv) are often found in chronically hbv-infected patients. it has not been possible to study the significance of such deletion mutants on liver diseases in a suitable animal model. in this study, we characterized naturally occurring deletion mutants of woodchuck hepatitis virus (whv) in 11 chronically whv-infected woodchucks. deletions within the whv pres region (nt 2992-338) had a length of 72 or 84 bp and were located in the amino terminal part of pres1. ... | 2000 | 11080471 |
| combination therapy with lamivudine and adenovirus causes transient suppression of chronic woodchuck hepatitis virus infections. | treatment of hepatitis b virus carriers with the nucleoside analog lamivudine suppresses virus replication. however, rather than completely eliminating the virus, long-term treatment often ends in the outgrowth of drug-resistant variants. using woodchucks chronically infected with woodchuck hepatitis virus (whv), we investigated the consequences of combining lamivudine treatment with immunotherapy mediated by an adenovirus superinfection. eight infected woodchucks were treated with lamivudine an ... | 2000 | 11090175 |
| antiviral l-nucleosides specific for hepatitis b virus infection. | a unique series of simple "unnatural" nucleosides has been discovered to inhibit hepatitis b virus (hbv) replication. through structure-activity analysis it was found that the 3'-oh group of the beta-l-2'-deoxyribose of the beta-l-2'-deoxynucleoside confers specific antihepadnavirus activity. the unsubstituted nucleosides beta-l-2'-deoxycytidine, beta-l-thymidine, and beta-l-2'-deoxyadenosine had the most potent, selective, and specific antiviral activity against hbv replication. human dna polym ... | 2001 | 11120971 |
| antiviral activity of clevudine [l-fmau, (1-(2-fluoro-5-methyl-beta, l-arabinofuranosyl) uracil)] against woodchuck hepatitis virus replication and gene expression in chronically infected woodchucks (marmota monax). | l: -fmau [1-(2-fluoro-5-methyl-beta,l-arabinofuranosyl) uracil] has been shown to be an effective inhibitor of hepatitis b virus (hbv) and duck hepatitis b virus replication in cell culture and duck hepatitis b virus replication in acutely infected peking ducks. the woodchuck hepatitis virus (whv) and its natural host, the eastern woodchuck (marmota monax), have been established as a predictive model for the evaluation of antiviral therapies against chronic hbv infection. in this report, the ant ... | 2001 | 11124844 |
| targeting murine immune responses to selected t cell- or antibody-defined determinants of the hepatitis b surface antigen by plasmid dna vaccines encoding chimeric antigen. | by exchanging sequences from the middle-surface (ms) and small-surface (s) ag of hepatitis b virus (hbv) with corresponding sequences of the ms ag of woodchuck hepatitis virus, we constructed chimeric ms variants. using these constructs as dna vaccines in mice, we selectively primed highly specific (non-cross-reactive) ab responses to pre-s2 of the hbv ms ag and the "a" determinant of the hbv s ag, as well as l(d)- or k(b)-restricted ctl responses to hbv s epitopes. in transgenic mice that const ... | 2001 | 11145726 |
| hepatitis b virus (hbv) virion and covalently closed circular dna formation in primary tupaia hepatocytes and human hepatoma cell lines upon hbv genome transduction with replication-defective adenovirus vectors. | hepatitis b virus (hbv), the causative agent of b-type hepatitis in humans, is a hepatotropic dna-containing virus that replicates via reverse transcription. because of its narrow host range, there is as yet no practical small-animal system for hbv infection. the hosts of the few related animal viruses, including woodchuck hepatitis b virus and duck hepatitis b virus, are either difficult to keep or only distantly related to humans. some evidence suggests that tree shrews (tupaias) may be suscep ... | 2001 | 11152483 |
| in vitro and in vivo infectivity and pathogenicity of the lymphoid cell-derived woodchuck hepatitis virus. | woodchuck hepatitis virus (whv) and human hepatitis b virus are closely related, highly hepatotropic mammalian dna viruses that also replicate in the lymphatic system. the infectivity and pathogenicity of hepadnaviruses propagating in lymphoid cells are under debate. in this study, hepato- and lymphotropism of whv produced by naturally infected lymphoid cells was examined in specifically established woodchuck hepatocyte and lymphoid cell cultures and coculture systems, and virus pathogenicity wa ... | 2001 | 11160675 |
| limited proteolysis induces woodchuck hepatitis virus infectivity for human hepg2 cells. | previous work from our laboratory has shown that digestion of hepatitis b virus (hbv) with v8 protease rendered the virus infectious for human hepatoblastoma cell line (hepg2). it was hypothesized that the cleavage exposes a 16 amino acid region that includes a consensus 'fusion' motif necessary to mediate infectivity. since woodchuck hepatitis virus (whv) and hbv possess significant homology in this region of their envelope proteins, including the v8 protease cleavage site, the possibility that ... | 2001 | 11163642 |
| antiviral efficacy of lobucavir (bms-180194), a cyclobutyl-guanosine nucleoside analogue, in the woodchuck (marmota monax) model of chronic hepatitis b virus (hbv) infection. | lobucavir (bms-180194), a cyclobutyl-guanosine nucleoside analogue, effectively reduced whv-viremia in chronically infected carrier woodchucks (marmota monax) by daily per os treatment. whv-viremia in the animals was measured by the serum content of hybridizable whv-genomic dna. lobucavir, given at daily doses of 10 and 20 mg/kg body weight, reduced whv-viremia by a 10- to 200-fold range during therapy. lobucavir, given at 5 mg/kg, suppressed whv-viremia by a 10- to 30-fold range, whereas a 0.5 ... | 2000 | 11164506 |
| immune responses following simian/human immunodeficiency virus (shiv) challenge of rhesus macaques after human immunodeficiency virus (hiv)-1 third variable domain (v3) loop-based genetic immunization. | following dna immunization of rhesus macaques with a plasmid encoding the human immunodeficiency virus (hiv)-1 third variable domain (v3) loop, presented by pseudo-viral envelope particles of hepatitis b virus, specific immune responses were induced. the primates were then inoculated with a chimeric simian/human immunodeficiency virus (shiv). all the animals were infected, but the v3-specific immunization provided a relative attenuation of the acute phase of infection in the absence of neutraliz ... | 2000 | 11168828 |
| key determinants in the occurrence of clonal variation in humanized antibody expression of cho cells during dihydrofolate reductase mediated gene amplification. | recombinant chinese hamster ovary (cho) parental clones expressing a humanized antibody against s surface antigen of hepatitis b virus were obtained by cotransfection of heavy chain (hc) and light chain (lc) cdna expression vectors into dihydrofolate reductase (dhfr)-deficient cho cells. when 23 representative parental clones were subjected to stepwise selection for increasing methotrexate (mtx) resistance, such as 0.02, 0.08, 0.32, and 1.0 microm, their clonal variations in regard to antibody e ... | 2001 | 11170482 |
| retrospective analysis of an outbreak of b virus infection in a colony of debrazza's monkeys (cercopithecus neglectus). | in 1981, an outbreak of herpetic disease developed in a colony of debrazza's monkeys (cercopithecus neglectus). in seven of eight infected animals, clinical signs of infection included vesicular and ulcerative lesions on the lips, tongue, and/or palate. histologic examination of lesions revealed intranuclear inclusion bodies, and electron microscopy revealed nucleocapsids and virions with typical herpesvirus morphology. although a virus was isolated that appeared similar to monkey b virus, techn ... | 2000 | 11200573 |
| animal models of hepadnavirus-associated hepatocellular carcinoma. | animal models of hepatitis b virus infection have been valuable for determining the mechanisms of hepadnavirus replication, for studies of pathogenesis, and for investigations of viral hepatocarcinogenesis. the woodchuck model also seems to be useful in the discovery and development of antiviral drugs to treat hbv infection and for testing new forms of immunotherapy. in particular, the woodchuck seems to be ideal for studying the effect of antiviral treatment and immunotherapy on the outcome of ... | 2001 | 11218919 |
| synovial stimulatory protein fragments copurify with woodchuck hepatitis virus: implications for the etiology of arthritis in chronic hepatitis b virus infection. | | 2001 | 11229482 |
| improved adenovirus vectors for infection of cardiovascular tissues. | to identify improved adenovirus vectors for cardiovascular gene therapy, a library of adenovirus vectors based on adenovirus serotype 5 (ad5) but carrying fiber molecules of other human serotypes, was generated. this library was tested for efficiency of infection of human primary vascular endothelial cells (ecs) and smooth muscle cells (smcs). based on luciferase, lacz, or green fluorescent protein (gfp) marker gene expression, several fiber chimeric vectors were identified that displayed improv ... | 2001 | 11238859 |
| experimental study on pathogenicity of precore mutants in hepadnaviridae. | to study the replicative competency and pathogenicity of precore gene mutants of duck hepatitis b virus (dhbv) in the duck model. | 1998 | 11245071 |
| antiviral activity of beta-l-2',3'-dideoxy-2',3'-didehydro-5-fluorocytidine in woodchucks chronically infected with woodchuck hepatitis virus. | the l-nucleoside analog beta-l-2',3'-dideoxy-2',3'-didehydro-5-fluorocytidine (beta-l-fd4c) was first shown to exhibit potent activity against hepatitis b virus (hbv) in tissue culture and then to significantly inhibit viral spread during acute infection in the duck hbv model (f. le guerhier et al., antimicrob. agents chemother. 44:111-122, 2000). we have therefore examined its antiviral activity in a mammalian model of chronic hbv infection, the woodchuck chronically infected with woodchuck hep ... | 2001 | 11257017 |
| expansion of hbv-specific memory ctl primed by dual hiv/hbv genetic immunization during shiv primary infection in rhesus macaques. | we have previously shown the induction of humoral and cytotoxic responses specific for human immunodeficiency virus (hiv) and hepatitis b virus (hbv) antigens, following genetic immunization of rhesus macaques with a plasmid encoding both the third variable domain of the hiv-1 external envelope glycoprotein and the pseudo-viral particle of hepatitis b surface antigen (hbsag) as presenting molecules. the dna-immunized primates and two control animals were then challenged with a chimeric simian/hu ... | 2001 | 11257382 |
| replication of naturally occurring woodchuck hepatitis virus deletion mutants in primary hepatocyte cultures and after transmission to naive woodchucks. | woodchuck hepatitis virus (whv) mutants with core internal deletions (cid) occur naturally in chronically whv-infected woodchucks, as do hepatitis b virus mutants in humans. we studied the replication of whv deletion mutants in primary woodchuck hepatocyte cultures and in vivo after transmission to naive woodchucks. by screening 14 wild-caught, chronically whv-infected woodchucks, two woodchucks, wh69 and wh70, were found to harbor whv cid mutants. consistent with previous results, whv cid mutan ... | 2001 | 11264370 |
| overexpression of bcl-2 inhibits sodium butyrate-induced apoptosis in chinese hamster ovary cells resulting in enhanced humanized antibody production. | sodium butyrate (nabu) can enhance the expression of genes from some of the mammalian promoters including cytomegalovirus (cmv) and simian virus 40 (sv40), but it can also inhibit cell growth and induce cellular apoptosis. thus, the beneficial effect of using a higher concentration of nabu on a foreign protein expression is compromised by its cytotoxic effect on cell growth. to overcome this cytotoxic effect of nabu, a survival protein, human bcl-2, was overexpressed in recombinant chinese hamst ... | 2000 | 11291028 |
| thymidine utilization abnormality in proliferating lymphocytes and hepatocytes of the woodchuck. | effective incorporation of tritiated thymidine ([(3)h]tdr) into proliferating lymphocytes is important because [(3)h]tdr is a standard label to study proliferate t-cell responses. we analyzed the thymidine utilization of woodchuck peripheral blood lymphocytes (pbl) since the [(3)h]tdr incorporation assay was not applicable to measure proliferative immune responses in the woodchuck, a current major virus/host model for human hepatitis b virus infection. incorporation of [(3)h]tdr into dna as well ... | 2001 | 11292529 |
| purification of woodchuck hepatitis surface antigen using a monoclonal antibody raised against the antigen. | woodchuck hepatitis virus (whv) is closely related to the human hepatitis b virus (hbv) and infection of woodchucks with whv creates a useful model for studies of immunity, pathogenesis and therapy of hbv infection. to increase the usefulness of this model, monoclonal antibodies were raised to woodchuck hepatitis surface antigen (whsag) and one of these antibodies was used to purify the antigen by affinity chromatography from serum, a simpler and quicker method of purification than the current u ... | 2001 | 11311348 |
| antiviral activity of a conjugate of adenine-9-beta-d-arabinofuranoside 5'-monophosphate and a 9 kda fragment of arabinogalactan. | an arabinogalactan conjugate containing a 9 kda fragment of arabinogalactan and adenine-9-beta-d-arabinofuranoside 5'-monophosphate (araamp), denoted ag(9 kda)-araamp, has been synthesized and characterized. in 2.2.15 (human hepatoblastoma) cells, the attachment of araamp to ag(9 kda), a ligand of the asialoglycoprotein receptor, decreased the effective concentration for inhibiting extracellular hepatitis b virus (hbv) production by 90% (ec90) from 17 to 0.9 microm adenine arabinoside (araa) equ ... | 1996 | 11322248 |
| efficient infection of primary tupaia hepatocytes with purified human and woolly monkey hepatitis b virus. | the asian tree shrew, tupaia belangeri, has been proposed as a novel animal model for studying hepatitis b virus (hbv) infection. here, we describe a protocol for efficient and reproducible infection of primary tupaia hepatocytes with hbv. we report that human serum interferes with hbv binding to the hepatocytes, thus limiting the maximum multiplicity of infection. purification of hbv virions by gradient sedimentation greatly enhances virus binding and infectivity. covalently closed circular dna ... | 2001 | 11333889 |
| novel helicobacter species isolated from rhesus monkeys with chronic idiopathic colitis. | chronic, idiopathic diffuse colitis is a well recognised clinical and pathological entity in captive rhesus monkeys. six rhesus monkeys were diagnosed with clinically debilitating, chronic diarrhoea. histologically, colonic tissues were characterised as chronic, moderate to severe colitis and typhlitis, with diffuse mononuclear inflammation of lamina propria, reactive lymphoid hyperplasia and multifocal micro-abscesses. colonic tissues were cultured for salmonella spp. and shigella spp.; all res ... | 2001 | 11339249 |
| cloning and expression of a novel hepatitis b virus-binding protein from hepg2 cells. | a direct involvement of the hepatitis b virus (hbv) pres1-(21-47) sequence in virus attachment to cell membrane receptor(s) and the presence on the plasma membranes of hepg2 cells of protein(s) with receptor activity for hbv have been suggested by many previous experiments. in this study, by using a tetravalent derivative of the pres1-(21-47) sequence, we have isolated by affinity chromatography from detergent-solubilized hepg2 plasma membranes a 44-kda protein (hbv-binding protein; hbv-bp), whi ... | 2001 | 11389143 |
| inhibition of hepatitis b virus dna replication by imino sugars without the inhibition of the dna polymerase: therapeutic implications. | previously we have shown that the imino sugar inhibitor of n-linked glycan processing, n-nonyl-deoxynojirimycin (n-nonyl-dnj), had antiviral activity in the woodchuck model of chronic hepatitis b virus (hbv) infection. in studying the mechanism of action of this compound, it was discovered that imino sugars could inhibit hbv secretion without inhibiting n-linked glycoprocessing. although n-nonyl-dnj is an inhibitor of the endoplasmic reticulum (er) glucosidase, here it is shown that n-nonyl-dnj ... | 2001 | 11391538 |
| prevalence of hepatitis b virus infections in nonhuman primates. | the aim of this study was to determine the prevalence of hepatitis b virus (hbv) infection in nonhuman primates. serum samples from europe, thailand and vietnam were analyzed. sera obtained from 262 apes and 454 monkeys were tested for hbv infection serologically and for hbv dna using nested pcr (npcr). a total number of 198 ape sera and all but one (cercopithecus aethiops) of the 4543 monkey sera had no serological signs of hbv infection. among the 64 of 262 (24.4%) seropositive ape sera, we fo ... | 2001 | 11396859 |
| the woodchuck model of hepatitis b virus infection. | the woodchuck hepatitis virus (whv) was the first of the mammalian and avian hepadnaviruses described after discovery of the virus of hepatitis b (hbv). woodchucks chronically infected with whv develop progressively severe hepatitis and hepatocellular carcinoma, which present as lesions that are remarkably similar to those associated with hbv infection in humans. the initial virological studies and studies of pathogenesis utilized woodchucks that had been trapped in the wild and had acquired whv ... | 2001 | 11406711 |
| animal models of hepatitis delta virus infection and disease. | hepatitis delta virus (hdv) is a defective rna virus with similarities to unusual subviral pathogens of higher plants. it requires hepatitis b virus (hbv) for its replication/transmission, and hbv-infected humans are the only established host. hdv causes both severe acute hepatitis and rapidly progressive chronic disease in some individuals. the hdv life cycle involves remarkable features, such as ribozyme- mediated autocatalytic processes, pol ii-directed rna synthesis from a single-stranded ci ... | 2001 | 11406712 |
| [application of dhfr gene negative chinese hamster ovary cell line to express hepatitis b virus surface antigen]. | to set up an efficient expressing system for recombinant hepatitis b virus surface antigen (hbsag) in dhfr gene negative cho cell line. | 2001 | 11436651 |
| experimental influenza b viral myositis. | to investigate the pathogenesis of influenza myositis in animals, juvenile balb/c mice were inoculated with influenza b/lee virus intramuscularly into the right quadriceps muscle. chicken normal allantoic fluid (naf) or phosphate-buffered saline (pbs) was injected into the left quadriceps of control mice and in some virus-infected mice. serum creatinine phosphokinase (cpk) levels rose significantly on days 1 and 2 post-inoculation (pi) in only virus-inoculated mice. on days 2 and 3 pi, right qua ... | 2001 | 11440746 |
| generation and characterization of a novel tetravalent bispecific antibody that binds to hepatitis b virus surface antigens. | hepatitis b virus (hbv) infection is a worldwide public health problem affecting about 350 million people. hbv envelope contains three surface antigens, called pre-s1, pre-s2 and s. for the prophylaxis of hbv infection, only an anti-s monoclonal antibody was tested for the protective efficacy against hbv infection, but it was shown to be incomplete. in addition, some immune escape mutants carrying mutations on the s antigen were reported. therefore, a multivalent bispecific antibody rather than ... | 2000 | 11451417 |
| t-helper cell response to woodchuck hepatitis virus antigens after therapeutic vaccination of chronically-infected animals treated with lamivudine. | immunotherapy of patients chronically-infected with hepatitis b virus (hbv) may have the risk of fulminant hepatitis. this risk might be diminished if immunotherapy was carried out under conditions of low viremia. | 2001 | 11495027 |
| management of hepatitis b virus infections in two gibbons and a western lowland gorilla in a zoological collection. | since 1996, three primates newly arrived at london zoo have been found to be infected with hepatitis b virus. the species involved were white-cheeked gibbons (hylobates leucogenys leucogenys and hylobates leucogenys siki) and a western lowland gorilla (gorilla gorilla gorilla). the protocols for the practical management of these cases, including the immunisation of susceptible non-human primates and the staff with recombinant hepatitis b vaccine are described, and the origin and evolution of hep ... | 2001 | 11504202 |
| evaluation of new approaches to prophylactic and therapeutic vaccinations against hepatitis b viruses in the woodchuck model. | the woodchuck model is most suitable for vaccine studies of prophylaxis and therapeutic treatment of hepatitis b virus infection. recently, methodological advances allowed the examination of antigen-specific t cell responses in woodchucks during woodchuck hepatitis virus (whv) infection and vaccinations. similar to hepatitis b virus infection in humans, multispecific t-cell responses to whv occur during acute self-limiting infection in woodchucks. immunizations with whv core antigen (whcag) or d ... | 2001 | 11509873 |
| vaccination against hepatitis delta virus infection: studies in the woodchuck (marmota monax) model. | hepatitis delta virus (hdv) superinfection of hepatitis b virus carriers causes severe liver disease and results in a high rate of chronicity. so far, neither sufficient therapy nor vaccines to prevent hbv carriers from superinfection are available. a good model to test vaccine candidates is the woodchuck chronically infected with the woodchuck hepatitis virus (whv); the woodchuck can be superinfected with hdv and shows a course of infection similar to that of patients. different strategies have ... | 2001 | 11509876 |
| detection of b virus infection in cynomolgus monkeys by elisa using simian agent 8 as alternative antigen. | the use of simian agent 8 (sa8) as an antigen for b virus (bv) antibody detection was evaluated in cynomolgus monkeys. seventy-two sera judged as positive using bv antigen were all positive when the sa8 antigen was used. out of 28 bv-negative sera 2 were positive against the sa8 antigen and one serum was classified as indeterminate. the present data indicates that detection of bv antibody can be achieved accurately and safely by enzyme-linked immunosorbent assay (elisa) using sa8 antigen. | 2001 | 11515100 |
| antibody responses of healthy infants to concurrent administration of a bivalent haemophilus influenzae type b-hepatitis b vaccine with diphtheria-tetanus-pertussis, polio and measles-mumps-rubella vaccines. | to confirm that children given a bivalent haemophilus influenzae type b-hepatitis b vaccine (bivalent hib-hb vaccine; comvax) concurrently with priming doses of diphtheria-tetanus-pertussis vaccine (dtp), a booster dose of diphtheria-tetanus-acellular pertussis vaccine (dtap), inactivated or oral polio vaccine (ipv or opv) and measles-mumps-rubella vaccine (m-m-r(ii)) have satisfactory antibody responses to all antigens. | 2001 | 11520252 |
| antiviral activity and intracellular metabolism of bis(tbutylsate) phosphotriester of beta-l-2',3'dideoxyadenosine, a potent inhibitor of hiv and hbv replication. | the beta-l-nucleoside analogue beta-l-2',3'-dideoxy adenosine (beta-l-dda) has been shown to exhibit limited antiviral activities. this was attributed to its rapid catabolism through cleavage of the glycosidic bond and poor phosphorylation to the nucleotide beta-l-2',3'-dideoxyadenosine-5'-mono phosphate (beta-l-ddamp) (placidi et al., 2000). however, the nucleotide beta-l-2',3'-dideoxyadenosine-5'-triphosphate (beta-l-ddatp) inhibited the activity of both hiv-1 reverse transcriptase (rt) and vi ... | 2001 | 11527047 |
| protection against woodchuck hepatitis virus (whv) infection by gene gun coimmunization with whv core and interleukin-12. | woodchuck hepatitis virus (whv) and hepatitis b virus (hbv) are closely similar with respect to genomic organization, host antiviral responses, and pathobiology of the infection. t-cell immunity against viral nucleocapsid (hbcag or whcag) has been shown to play a critical role in viral clearance and protection against infection. here we show that vaccination of healthy woodchucks by gene gun bombardment with a plasmid coding for whcag (pcw) stimulates proliferation of whcag-specific t cells but ... | 2001 | 11533170 |
| immunogenicity of a dna vaccine against herpes b virus in mice and rhesus macaques. | herpes b virus (cercopithecine herpesvirus 1) is endemic in captive macaque populations and poses a serious threat to humans who work with macaques or their tissues. a vaccine that could prevent or limit b virus infection in macaques would lessen occupational risk. to that end, a dna vaccine plasmid expressing the b virus glycoprotein b (gb) was constructed and tested for immunogenicity in mice and macaques. intramuscular (im) or intradermal (id) immunization in mice elicited antibodies to gb th ... | 2001 | 11535340 |
| paired chimpanzee hepatitis b virus (chhbv) and mtdna sequences suggest different chhbv genetic variants are found in geographically distinct chimpanzee subspecies. | the surface antigen gene region from five chronic hepatitis b virus (hbv) infected chimpanzees was amplified by pcr and the sequence determined. sequence comparison confirmed that all of the sequences were chimpanzee hepatitis b virus (chhbv) and they appeared to represent three distinct clusters or branches. to address the question of whether the three branches represented recently identified subspecies of chimpanzees, we determined the sequence of the mitochondrial dna hypervariable d loop fro ... | 2001 | 11551650 |
| anti-hbv specific beta-l-2'-deoxynucleosides. | a unique series of simple unnatural l-nucleosides that specifically inhibit hepatitis b virus (hbv) replication has been discovered. these molecules have in common a hydroxyl group in the 3'-position (3'-oh) of the beta-l-2'-deoxyribose sugar that confers antiviral activity specifically against hepadnaviruses. replacement of the 3'-oh broadens activity to other viruses. substitution in the base decreases antiviral potency and selectivity. human dna polymerases and mitochondrial function are not ... | 2001 | 11563077 |
| entecavir (bristol-myers squibb). | bristol-myers squibb (bms) is developing entecavir, a viral replication inhibitor, for the potential treatment of hepatitis b virus (hbv) infection [220240]. the compound is a cyclopentyl guanosine analog and is in phase ii trials in the us [383065]. entecavir was originally developed as sq-34676 for the treatment of herpes simplex virus infections [221992], but displayed only moderate activity which eventually led to discontinuation of development for this indication. however, bristol-myers squ ... | 2001 | 11569933 |
| the replication of certain coxsackie b virus strains in cho cells. | cell surface molecules that can act as viral receptors may exert an important selective pressure on rna viral quasi-species. coxsackie-adenovirus receptor and decay accelerating factor (daf, cd55) have been identified as receptors for coxsackie b virus. in studies of viral replication using different strains of coxsackievirus serotype 4 (cbv-4), it was found that despite lack of expression of these cell surface molecules on chinese hamster ovary (cho) cells and despite their common use as negati ... | 2001 | 11576643 |
| ddb2 induces nuclear accumulation of the hepatitis b virus x protein independently of binding to ddb1. | the hepatitis b virus (hbv) x protein (hbx) is critical for the life cycle of the virus. hbx associates with several host cell proteins including the ddb1 subunit of the damaged-dna binding protein ddb. recent studies on the x protein encoded by the woodchuck hepadnavirus have provided correlative evidence indicating that the interaction with ddb1 is important for establishment of infection by the virus. in addition, the interaction with ddb1 has been implicated in the nuclear localization of hb ... | 2001 | 11581406 |
| woodchuck hepatocytes remain permissive for hepadnavirus infection and mouse liver repopulation after cryopreservation. | isolated hepatocytes represent a relevant model of the liver and are highly required both for research and therapeutic applications. however, sources of primary liver cells from human beings and from some animal species are limited. therefore, cryopreservation of hepatocytes could greatly facilitate advances in various research areas. the aim of this study was to evaluate whether cryopreserved primary woodchuck hepatocytes could be used for woodchuck hepatitis b virus (whv) infection studies, an ... | 2001 | 11584382 |
| antiviral beta-l-nucleosides specific for hepatitis b virus infection. | three simple, related nucleosides, beta-l-2'-deoxycytidine (ldc), beta-lthymidine (ldt), and beta-l-2'-deoxyadenosine (lda), have been discovered to be potent, specific and selective inhibitors of the replication hepatitis b virus (hbv), as well as the closely related duck and woodchuck hepatitis viruses (whv). structure-activity relationship analysis indicates that the 3'-oh group of the beta-l-2'-deoxyribose of the beta-l-2'-deoxynucleoside confers specific anti-hepadnavirus activity. the simp ... | 2001 | 11594678 |
| evaluation of novel strategies to combat hepatitis b virus targetting wild-type and drug-resistant mutants in experimental models. | recent studies have shown that the kinetics of hepatitis b virus (hbv) clearance during antiviral therapy are slow, requiring long-term therapy to control viral replication. it has also been shown that emergence of resistant mutants is accelerated by high hbv replication and hepatocyte turnover, which are common features in patients with chronic hbv infection. it is therefore important to continue research on novel antiviral agents to design optimal combination strategies. the duck and woodchuck ... | 2001 | 11594680 |
| identification and analysis of a new hepadnavirus in white storks. | we identified, cloned, and functionally characterized a new avian hepadnavirus infecting storks (sthbv). sthbv has the largest dna genome of all avian hepadnaviruses and, based on sequence and phylogenetic analysis, is most closely related to, but distinct from, heron hepatitis b virus (hhbv). unique for sthbv among the other avian hepadnaviruses is a potential hnf1 binding site in the pres promoter. in common only with hhbv, sthbv has a myristylation signal on the s and not the pres protein, tw ... | 2001 | 11601923 |
| a short sequence within domain c of duck carboxypeptidase d is critical for duck hepatitis b virus binding and determines host specificity. | virus-cell surface receptor interactions are of major interest. hepadnaviruses are a family of partially double-stranded dna viruses with liver tropism and a narrow host range of susceptibility to infection. at least in the case of duck hepatitis b virus (dhbv), host specificity seems controlled partly at the receptor level. the middle portion in the pre-s region of the viral large envelope protein binds specifically to duck carboxypeptidase d (dcpd) but not to its human or chicken homologue. al ... | 2001 | 11602705 |