bluuebunny/crossref_metadata_2025_split huggingface dataset:
Clinical Relevance of the
babA2
Genotype of
Helicobacter pylori
in Japanese Clinical Isolates
Authors: Mizushima Takuji , Sugiyama Toshiro , Komatsu Yoshito , Ishizuka Jun , Kato Mototsgu , Asaka Masahiro 
Published: July 2002

ABSTRACT

Genotypic variation of
Helicobacter pylori
is speculated to associate with different clinical outcomes. In Western countries, the gene encoding blood group antigen-binding adhesin (BabA),
babA2
, is of high clinical relevance and is a useful marker to identify patients who are at higher risk for peptic ulceration and gastric adenocarcinoma, as are
vacA
and
cagA
. We investigated the presence of
babA2
and
cagA
in 179 Japanese clinical isolates by PCR and Southern blot analysis and looked for correlations with various clinical outcomes (nonulcer dyspepsia, duodenal ulcers, gastric ulcers gastric adenocarcinoma, and mucosa-associated lymphoid tissue lymphoma). The prevalence of the
babA2
genotype was 84.9% and that of the
cagA
genotype was 96.1%. There was no correlation between the
babA2
and
cagA
genotypes, and there was no association between the
babA2
or
cagA
status and clinical outcome. These results indicate that
babA2
status is not of high clinical relevance in Japan and that Japanese strains are different from those infecting Western populations.
Quantitative Detection of
Borrelia burgdorferi
in 2-Millimeter Skin Samples of Erythema Migrans Lesions: Correlation of Results with Clinical and Laboratory Findings
Authors: Liveris Dionysios , Wang Guiqing , Girao Gary , Byrne Daniel W. , Nowakowski John , McKenna Donna , Nadelman Robert , Wormser Gary P. , Schwartz Ira 
Published: July 2002

ABSTRACT

Variability of disease manifestations has been noted in patients with Lyme disease. A contributing factor to this variation may be the number of spirochetes present in infected patients. We evaluated clinical and laboratory findings for patients with erythema migrans with regard to the number of
Borrelia burgdorferi
organisms detected by quantitative PCR (qPCR) in 2-mm skin biopsy specimens.
B. burgdorferi
was detected in 80% (40 of 50) of the specimens tested; the mean number of spirochetes in these specimens ranged over 3 orders of magnitude (10 to 11,000 spirochetes per 2-mm biopsy specimen). Larger numbers of spirochetes were significantly associated with a shorter duration of the erythema migrans skin lesion (
P
= 0.020), smaller skin lesions (
P
= 0.020), and infection with a specific genotype of
B. burgdorferi
(
P
= 0.008) but not with the number or severity of symptoms. Skin culture positivity was significantly associated with skin lesions containing larger numbers of spirochetes (
P
= 0.019).
Coronavirus-Induced Demyelination Occurs in the Absence of Inducible Nitric Oxide Synthase
Authors: Wu Gregory F. , Pewe Lecia , Perlman Stanley 
Published: July 2002

ABSTRACTDemyelination induced by mouse hepatitis virus (MHV), strain JHM, is in large part immune mediated, but little is known about the mechanisms involved in this process. Previous results suggest that inducible nitric oxide synthase (NOS2) contributes transiently to MHV-induced demyelination. Herein, we show that equivalent amounts of demyelination were evident at day 12 after MHV infection in mice genetically deficient in NOS2 (NOS2−/−) and in C57BL/6 mice. Furthermore, using an established adoptive transfer model and pharmacological inhibitors of NOS2 function, we could demonstrate no effect on MHV-induced demyelination. These results indicate that NOS2 function is not required for demyelination in mice infected with MHV.
Selective Cleavage of AAVS1 Substrates by the Adeno-Associated Virus Type 2 Rep68 Protein Is Dependent on Topological and Sequence Constraints
Authors: Lamartina Stefania , Ciliberto Gennaro , Toniatti Carlo 
Published: July 2002

ABSTRACT

The adeno-associated virus type 2 (AAV-2) Rep78 and Rep68 proteins are required for replication of the virus as well as its site-specific integration into a unique site, called AAVS1, of human chromosome 19. Rep78 and Rep68 initiate replication by binding to a Rep binding site (RBS) contained in the AAV-2 inverted terminal repeats (ITRs) and then specifically nicking at a nearby site called the terminal resolution site (
trs
). Similarly, Rep78 and Rep68 are postulated to trigger the integration process by binding and nicking RBS and
trs
homologues present in AAVS1. However, Rep78 and Rep68 cleave in vitro AAVS1 duplex-linear substrates much less efficiently than hairpinned ITRs. In this study, we show that the AAV-2 Rep68 endonuclease activity is affected by the topology of the substrates in that it efficiently cleaves in vitro in a site- and strand-specific manner the AAVS1
trs
only if this sequence is in a supercoiled (SC) conformation. DNA sequence mutagenesis in the context of SC templates allowed us to elucidate for the first time the AAVS1
trs
sequence and position requirements for Rep68-mediated cleavage. Interestingly, Rep68 did not cleave SC templates containing RBS from other sites of the human genome. These findings have intriguing implications for AAV-2 site-specific integration in vivo.
The Human Herpesvirus 8 Homolog of Epstein-Barr Virus SM Protein (KS-SM) Is a Posttranscriptional Activator of Gene Expression
Authors: Gupta Ashish K. , Ruvolo Vivian , Patterson Cam , Swaminathan Sankar 
Published: July 2002

ABSTRACTHomologs of the Epstein-Barr virus (EBV) SM protein exist in several human and nonhuman herpesviruses. Structure and function differ significantly among these proteins. We have cloned and characterized the human herpesvirus 8 (HHV8) gene, KS-SM, which is homologous to the EBV SM and herpes simplex virus ICP27 genes, from an HHV8-infected primary effusion lymphoma. KS-SM is shown to be a posttranscriptional activator of gene expression in cotransfection studies. KS-SM activated gene expression in a gene-specific, promoter-independent manner. In particular, KS-SM enhanced the expression of KDR/flk-1, a receptor for vascular endothelial growth factor (VEGF), in cotransfection studies. Since expression of KDR/flk-1 is increased in Kaposi's sarcoma and HHV8-infected cell cultures and VEGF enhances the proliferation of HHV8-infected cells, KS-SM may play a pathogenic role in Kaposi's sarcoma.
Prevention of Adult T-Cell Leukemia-Like Lymphoproliferative Disease in Rats by Adoptively Transferred T Cells from a Donor Immunized with Human T-Cell Leukemia Virus Type 1 Tax-Coding DNA Vaccine
Authors: Ohashi Takashi , Hanabuchi Shino , Kato Hirotomo , Tateno Hiromi , Takemura Fumiyo , Tsukahara Tomonori , Koya Yoshihiro , Hasegawa Atsuhiko , Masuda Takao , Kannagi Mari 
Published: July 2002

ABSTRACTHuman T-cell leukemia virus type 1 (HTLV-1) causes adult T-cell leukemia (ATL) in infected individuals after a long incubation period. To dissect the mechanisms of the development of the disease, we have previously established a rat model of ATL-like disease which allows examination of the growth and spread of HTLV-1 infected tumor cells, as well assessment of the effects of immune T cells on the development of the disease. In the present study, we induced HTLV-1 Tax-specific cytotoxic T lymphocyte (CTL) immunity by vaccination with Tax-coding DNA and examined the effects of the DNA vaccine in our rat ATL-like disease model. Our results demonstrated that DNA vaccine with Tax effectively induced Tax-specific CTL activity in F344/N Jcl-rnu/+ (nu/+) rats and that these CTLs were able to lyse HTLV-1 infected syngeneic T cells in vitro. Adoptive transfer of these immune T cells effectively inhibited the in vivo growth of HTLV-1-transformed tumor in F344/N Jcl-rnu/rnu (nu/nu) rats inoculated with a rat HTLV-1 infected T cell line. Vaccination with mutant Tax DNA lacking transforming ability also induced efficient anti-tumor immunity in this model. Our results indicated a promising effect for DNA vaccine with HTLV-1 Tax against HTLV-1 tumor development in vivo.
Comparison of Second-Strand Transfer Requirements and RNase H Cleavages Catalyzed by Human Immunodeficiency Virus Type 1 Reverse Transcriptase (RT) and E478Q RT
Authors: Snyder Christine Smith , Roth Monica J. 
Published: July 2002

ABSTRACT

Truncated tRNA-DNA mimics were examined in an in vitro assay for second-strand transfer during human immunodeficiency virus type 1 (HIV-1) reverse transcription. Strand transfer in this system requires the progressive degradation of the RNA within the 18-mer tRNA-DNA (plus-strand strong stop DNA) intermediate to products approximately 8 nucleotides in length. The ability of the truncated substrates to substitute for directional processing by RNase H or reverse transcriptase (RT) was examined. Using wild-type HIV-1 RT, substrates which truncated the 5′ end of the tRNA primer by 6, 9, and 12 nucleotides (Δ6, Δ9, and Δ12, respectively) were recognized by RNase H and resulted in strand transfer. An overlap of 5 nucleotides between the acceptor and newly synthesized DNA template was sufficient for strand transfer. The mutant RT, E478Q correctly catalyzed the initial cleavage of the 18-mer tRNA-DNA mimic in the presence of Mn
2+
; however, no directional processing was observed. In contrast, no RNase H activity was observed with the Δ6, Δ9, and Δ12 substrates with E478Q RT in this strand transfer assay. However, when complemented with
Escherichia coli
RNase H, E478Q RT supported strand transfer with the truncated substrates. E478Q RT did cleave the truncated forms of the substrates, Δ6, Δ9, and Δ12, in a polymerase-independent assay. The size requirements of the substrates which were cleaved by the polymerase-independent RNase H activity of E478Q RT are defined.
Core Protein-Coding Sequence, but Not Core Protein, Modulates the Efficiency of Cap-Independent Translation Directed by the Internal Ribosome Entry Site of Hepatitis C Virus
Authors: Wang Ting-Hsien , Rijnbrand René C. A. , Lemon Stanley M. 
Published: July 2002

ABSTRACTAmong a myriad of putative functions assigned to the hepatitis C virus (HCV) core protein, several studies suggest that it may modulate internal ribosome entry site (IRES)-mediated initiation of translation. We compared the translational activity of dicistronic reporter transcripts containing the HCV IRES within the intercistronic space fused to downstream sequence encoding either 22 amino acids (aa) or 173 aa of the core protein. The inclusion of the nearly full-length core protein-coding sequence significantly suppressed translation in vitro and in transfected HepG2 cells. However, this suppression was not eliminated by frameshift mutations introduced into the core sequence, suggesting that it occurred at the RNA level and not as a result of core protein expression incis. Similarly, the expression of core protein (aa 1 to 191) intransfrom a recombinant baculovirus did not suppress IRES-directed translation from any of these transcripts in transfected Huh-7 cells. While core protein expression did decrease IRES activity in HepG2 cells (up to 79% suppression), the expression of β-galactosidase from a control baculovirus also suppressed IRES activity (up to 56%), strongly suggesting that this suppression was nonspecific. Finally, the addition of purified recombinant core protein (aa 1 to 179) to in vitro translation reactions at concentrations up to a 10-fold molar excess over the RNA transcripts resulted in no significant reduction in IRES activity. Consistent with these results, a gel retention assay indicated no difference in the affinities of the recombinant HCV core protein and a recombinant Venezuelan equine encephalitis virus capsid protein for HCV IRES-containing RNA transcripts. We conclude that while the inclusion of core protein-coding sequence downstream of the IRES may reduce the efficiency of cap-independent translation on HCV RNA, the core protein itself has no biologically relevant activity in modulating HCV IRES activity.
Sint1
, a Common Integration Site in SL3-3-Induced T-Cell Lymphomas, Harbors a Putative Proto-Oncogene with Homology to the Septin Gene Family
Authors: Sørensen Annette Balle , Lund Anders H. , Ethelberg Steen , Copeland Neal G. , Jenkins Nancy A. , Pedersen Finn Skou 
Published: July 2002

ABSTRACT

The murine retrovirus SL3-3 is a potent inducer of T-cell lymphomas when inoculated into susceptible newborn mice. Previously, DNAs from twenty SL3-3-induced tumors were screened by PCR for provirus integration sites. Two out of 20 tumors demonstrated clonal provirus insertion into a common region. This region has now been isolated and characterized. The region, named SL3-3 integration site 1 (
Sint1
), maps to the distal end of mouse chromosome 11, corresponding to human chromosome 17q25, and may be identical to a mouse mammary tumor virus integration site in a T-cell lymphoma,
Pad3
. Two overlapping genomic λ clones spanning about 35 kb were isolated and used as a starting point for a search for genes in the neighborhood of the virus integration sites. A genomic fragment was used as a hybridization probe to isolate a 3-kb cDNA clone, the expression of which was upregulated in one of two tumors harboring a provirus in
Sint1
. The cDNA clone is predicted to encode a protein which shows 97.0% identity to a human septin-like protein encoded by a gene which has been found as a fusion partner gene of MLL in an acute myeloid leukemia with a t(11;17)(q23;q25). Together these findings raise the possibility that a proto-oncogene belonging to the septin family, and located about 15 kb upstream of the provirus integration sites, is involved in murine leukemia virus-induced T-cell lymphomagenesis.
Downregulation of p56lckTyrosine Kinase Activity in T Cells of Squirrel Monkeys (Saimiri sciureus) Correlates with the Nontransforming and Apathogenic Properties of Herpesvirus Saimiri in Its Natural Host
Authors: Greve Timm , Tamgüney Gültekin , Fleischer Bernhard , Fickenscher Helmut , Bröker Barbara M. 
Published: July 2002

ABSTRACTHerpesvirus saimiri is capable of transforming T lymphocytes of various primate species to stable growth in culture. The interaction of the T-cellular tyrosine kinase p56lckwith the transformation-associated viral protein Tip has been shown before to activate the kinase and provides one model for the T-cell-specific transformation by herpesvirus saimiri subgroup C strains. In contrast to other primate species, squirrel monkeys (Saimiri sciureus) are naturally infected with the virus without signs of lymphoma or other disease. Although the endogenous virus was regularly recovered from peripheral blood cells from squirrel monkeys, we observed that the T cells lost the virus genomes in culture. Superinfection with virus strain C488 did not induce growth transformation, in contrast to parallel experiments with T cells of other primate species. Surprisingly, p56lckwas enzymatically inactive in primary T-cell lines derived from different squirrel monkeys, although the T cells reacted appropriately to stimulatory signals. The cDNA sequence revealed minor point mutations only, and transfections in COS-7 cells demonstrated that theS. sciureus lckgene codes for a functional enzyme. InS. sciureus, the tyrosine kinase p56lckwas not activated after T-cell stimulation and enzymatic activity could not be induced by Tip of herpesvirus saimiri C488. However, the suppression of p56lckwas partially released after administration of the phosphatase inhibitor pervanadate. This argues for unique species-specific conditions in T cells ofS. sciureuswhich may interfere with the transforming activity and pathogenicity of herpesvirus saimiri subgroup C strains in their natural host.
Protective Mechanisms Induced by a Japanese Encephalitis Virus DNA Vaccine: Requirement for Antibody but Not CD8+Cytotoxic T-Cell Responses
Authors: Pan Chien-Hsiung , Chen Hsin-Wei , Huang Hui-Wen , Tao Mi-Hua 
Published: July 2002

ABSTRACTWe have previously shown that a plasmid (pE) encoding the Japanese encephalitis virus (JEV) envelope (E) protein conferred a high level of protection against a lethal viral challenge. In the present study, we used adoptive transfer experiments and gene knockout mice to demonstrate that the DNA-induced E-specific antibody alone can confer protection in the absence of cytotoxic T-lymphocyte (CTL) functions. Plasmid pE administered by either intramuscular or gene gun injection produced significant E-specific antibodies, helper T (Th)-cell proliferative responses, and CTL activities. Animals receiving suboptimal DNA vaccination produced low titers of anti-E antibodies and were only partially or not protected from viral challenge, indicating a strong correlation between anti-E antibodies and the protective capacity. This observation was confirmed by adoptive transfer experiments. Intravenous transfer of E-specific antisera but not crude or T-cell-enriched immune splenocytes to sublethally irradiated hosts conferred protection against a lethal JEV challenge. Furthermore, experiments with gene knockout mice showed that DNA vaccination did not induce anti-E titers and protective immunity in Igμ−/−and I-Aβ−/−mice, whereas in CD8α−/−mice the pE-induced antibody titers and protective rate were comparable to those produced in the wild-type mice. Taken together, these results demonstrate that the anti-E antibody is the most critical protective component in this JEV challenge model and that production of anti-E antibody by pE DNA vaccine is dependent on the presence of CD4+T cells but independent of CD8+T cells.
Granulocyte-Macrophage Colony-Stimulating Factor Expressed by Recombinant Respiratory Syncytial Virus Attenuates Viral Replication and Increases the Level of Pulmonary Antigen-Presenting Cells
Authors: Bukreyev Alexander , Belyakov Igor M. , Berzofsky Jay A. , Murphy Brian R. , Collins Peter L. 
Published: July 2002

ABSTRACTAn obstacle to developing a vaccine against human respiratory syncytial virus (RSV) is that natural infection typically does not confer solid immunity to reinfection. To investigate methods to augment the immune response, recombinant RSV (rRSV) was constructed that expresses murine granulocyte-macrophage colony-stimulating factor (mGM-CSF) from a transcription cassette inserted into the G-F intergenic region. Replication of rRSV/mGM-CSF in the upper and lower respiratory tracts of BALB/c mice was reduced 23- to 74- and 5- to 588-fold, respectively, compared to that of the parental rRSV. Despite this strong attenuation of replication, the level of RSV-specific serum antibodies induced by rRSV/mGM-CSF was comparable to, or marginally higher than, that of the parental rRSV. The induction of RSV-specific CD8+cytotoxic T cells was moderately reduced during the initial infection, which might be a consequence of reduced antigen expression. Mice infected with rRSV/mGM-CSF had elevated levels of pulmonary mRNA for gamma interferon (IFN-γ) and interleukin 12 (IL-12) p40 compared to animals infected by wild-type rRSV. Elevated synthesis of IFN-γ could account for the restriction of RSV replication, as was observed previously with an IFN-γ-expressing rRSV. The accumulation of total pulmonary mononuclear cells and total CD4+T lymphocytes was accelerated in animals infected with rRSV/mGM-CSF compared to that in animals infected with the control virus, and the level of IFN-γ-positive or IL-4-positive pulmonary CD4+cells was elevated approximately twofold. The number of pulmonary lymphoid and myeloid dendritic cells and macrophages was increased up to fourfold in mice infected with rRSV/mGM-CSF compared to those infected with the parental rRSV, and the mean expression of major histocompatibility complex class II molecules, a marker of activation, was significantly increased in the two subsets of dendritic cells. Enhanced antigen presentation likely accounts for the maintenance of a strong antibody response despite reduced viral replication and would be a desirable property for a live attenuated rRSV vaccine.
Mad-1 Is the Exclusive JC Virus Strain Present in the Human Colon, and Its Transcriptional Control Region Has a Deleted 98-Base-Pair Sequence in Colon Cancer Tissues
Authors: Ricciardiello Luigi , Chang Dong K. , Laghi Luigi , Goel Ajay , Chang Christina L. , Boland C. Richard 
Published: July 2002

ABSTRACT

JC virus (JCV), along with other members of the polyomavirus family, encodes a class of highly conserved proteins, T antigens, that are capable of inducing aneuploidy in cultured cells. We have previously isolated T-antigen DNA variants of JCV from both colon cancer tissues and the corresponding nonneoplastic gastrointestinal tissues, raising new questions about the role of JCV in the development of chromosomal instability of the colon. Based on the sequence of the transcriptional control region (TCR), JCV can be classified as archetype or tandem repeat variants. Among the latter, Mad-1, the prototype virus first isolated from a patient with progressive multifocal leukoencephalopathy, is characterized by lacking the 23- and 66-bp sequences that are present in the archetype and by duplication of a 98-bp sequence. In this study, we evaluated differences in the TCR of JCV isolated from colon cancer tissues and nonneoplastic epithelium. To characterize JCV variants, we first treated eight pairs of DNA samples from colon cancers and noncancerous tissue with topoisomerase I and then amplified and cloned the JCV TCR. We obtained 285 recombinant clones from the JCV TCR, 157 from nonneoplastic samples, and 128 from colon cancer tissues. Of these clones, 262 spanned the length of the JCV Mad-1 TCR: 99.3% from nonneoplastic samples and 82.8% from colon cancer tissues. In sequencing 54 clones in both directions, we did not find archetype JCV either in the nonneoplastic tissue or in the cancer samples. From all colon cancer tissues, 18 clones had a deletion of one 98-bp tandem repeat. This deleted strain was not detected in any of the nonneoplastic tissues (14 versus 0% [χ
2
= 23.6;
P
< 0.001]). Our study demonstrates that the only JCV strain present in the human colon is Mad-1, and the variant with a single 98-bp sequence is found exclusively in the cancer tissues. This strain may be involved in the development of chromosomal instability.
Analysis of Protein Expression from within the Region Encoding the 2.0-Kilobase Latency-Associated Transcript of Herpes Simplex Virus Type 1
Authors: Lock Martin , Miller Cathie , Fraser Nigel W. 
Published: July 2002

ABSTRACT
During latent infections of sensory neurons, herpes simplex virus type 1 gene expression is restricted to the latency-associated transcripts (LATs). The association of the stable 2.0-kb LAT intron with polysomes has suggested that it might represent a novel mRNA. In this work, we investigated expression of 2.0-kb LAT open reading frames (ORFs) by inserting the gene for green fluorescent protein (GFP) within the 2.0-kb LAT sequence, both within a LAT expression plasmid and in the context of the virus. Upon transient transfection of cells of both neuronal and nonneuronal origin with LAT-GFP expression vectors, low-level GFP fluorescence was distributed over the cell cytoplasm and likely resulted from infrequent initiation at a GFP AUG codon, on either unspliced or alternately spliced LAT RNAs. A second nucleolar GFP expression pattern which resulted from fusion of GFP to a conserved ORF in exon 1 of the LAT gene was also observed. However, the abundant expression of this fusion protein was dependent upon an artificially added translation initiation codon. Expression was much reduced and restricted to a small subset of transfected cells when this initator codon was removed. Neither the 2.0-kb LAT-GFP intron itself nor transcripts originating from the latency-associated promoter 2 (LAP2) were responsible for GFP expression. Abundant alternate splicing involving the 1.5-kb LAT splice acceptor and including splicing between the 1.5-kb LAT splice donor and acceptor, was observed in the nonneuronal Cos-1 cell line. Contrary to the results of our transfection studies, GFP expression could not be detected from a LAT-GFP virus at any stage of the infection cycle. Our results suggest that the inhibition of LAT ORF expression during viral infection occurred primarily at the level of translation.