bluuebunny/crossref_metadata_2025_split huggingface dataset:
Transformation of Rodent Fibroblasts by the Jaagsiekte Sheep Retrovirus Envelope Is Receptor Independent and Does Not Require the Surface Domain
Authors: Chow Yen-Hung J. , Alberti Alberto , Mura Manuela , Pretto Carla , Murcia Pablo , Albritton Lorraine M. , Palmarini Massimo 
Published: May 2003

ABSTRACT
Jaagsiekte sheep retrovirus (JSRV) is the etiological agent of a contagious lung cancer of sheep known as ovine pulmonary adenocarcinoma (OPA). Expression of the JSRV envelope protein (Env) is sufficient to transform immortalized and primary fibroblasts, but the precise mechanisms of this process are not known. The cellular receptor for JSRV is hyaluronidase 2 (Hyal-2), the product of a putative tumor suppressor gene that in humans maps to a chromosomal region frequently deleted in the development of lung and breast cancers. Here we report studies to determine whether the Hyal-2-JSRV Env interaction plays a role in virus-induced transformation of rodent fibroblasts. Chimeric Env proteins between JSRV and the unrelated murine retroviruses Moloney murine leukemia virus (MMuLV) and mouse mammary tumor virus (MMTV) showed cell surface expression comparable to that of wild-type MMuLV Env and rescued infection of MMuLV particle pseudotypes. Interestingly, an MMuLV-JSRV chimera in which the putative receptor binding domain (RBD) and proline-rich region (PRR) of JSRV Env were replaced by the RBD and PRR of MMuLV induced transformation of 208F, a rodent fibroblast line. Cell lines derived from foci of MMuLV-JSRV chimera-transformed 208F cells grew in soft agar and showed Akt activation, a hallmark of JSRV-transformed rodent fibroblasts. Transformation assays performed using proteins with amino-terminal deletion mutations showed that the carboxy-terminal 141 amino acids of the transmembrane subunit (TM) were sufficient to induce cell transformation when targeted to the membrane with a myristoylation signal. Thus, the JSRV TM is necessary and sufficient to transform rodent fibroblasts. Taken together these results indicate that the interaction with Hyal-2 at least is not an essential determinant of JSRV-induced transformation of fibroblasts and that the viral TM functions essentially as an oncoprotein.
U.S. Human Immunodeficiency Virus Type 1 Epidemic: Date of Origin, Population History, and Characterization of Early Strains
Authors: Robbins Kenneth E. , Lemey Philippe , Pybus Oliver G. , Jaffe Harold W. , Youngpairoj Ae S. , Brown Teresa M. , Salemi Marco , Vandamme Anne-Mieke , Kalish Marcia L. 
Published: May 2003

ABSTRACTHuman immunodeficiency virus (HIV) type 1 subtype B sequences (whole envelope and the p17 region ofgag) were obtained from peripheral blood mononuclear cell samples collected in 1981 from seven HIV-infected U.S. individuals and in 1982 from one infected Canadian resident. Phylogenetic and nucleotide distance analyses were performed by using database sequences representing North American strains collected from 1978 to 1995. The estimated phylogeny was starlike, with early strains represented on different lineages. When sequences were grouped by years of collection, nucleotide distance comparisons demonstrated an increase in diversity over time and indicated that contemporary strains are more closely related to early epidemic strains than to each other. Using a recently developed likelihood ratio reduction procedure, the date of origin of the U.S. epidemic was estimated to be 1968 ± 1.4 years. A coalescent approach was also used to estimate the population history of the U.S. subtype B epidemic. Our analyses provide new information that implies an exponential growth rate from the beginning of the U.S. HIV epidemic. The dating results suggest a U.S. introduction date (or date of divergence from the most recent common ancestor) that precedes the date of the earliest known AIDS cases in the late 1970s. Furthermore, the estimated epidemic growth curve shows a period of exponential growth that preceded most of the early documented cases and also indicates a leveling of prevalence rates in the recent past.
Intracellular Targeting of Gag Proteins of theDrosophilaTelomeric Retrotransposons
Authors: Rashkova S. , Athanasiadis A. , Pardue M.-L. 
Published: May 2003

ABSTRACTDrosophilahas two non-long-terminal-repeat (non-LTR) retrotransposons that are unique because they have a defined role in chromosome maintenance. These elements,HeT-AandTART, extend chromosome ends by successive transpositions, producing long arrays of head-to-tail repeat sequences. These arrays appear to be analogous to the arrays produced by telomerase on chromosomes of other organisms. While other non-LTR retrotransposons transpose to many chromosomal sites,HeT-AandTARTtranspose only to chromosome ends. AlthoughHeT-AandTARTbelong to different subfamilies of non-LTR retrotransposons, they encode very similar Gag proteins, which suggests that Gag proteins are involved in their unique transposition targeting. We have recently shown that both Gags localize efficiently to nuclei whereHeT-AGag forms structures associated with telomeres.TARTGag does not associate with telomeres unlessHeT-AGag is present, suggesting a symbiotic relationship in whichHeT-AGag provides telomeric targeting. We now report studies to identify amino acid regions responsible for different aspects of the intracellular targeting of these proteins. Green fluorescent protein-tagged deletion derivatives were expressed in culturedDrosophilacells. The intracellular localization of these proteins shows the following. (i) Several regions that direct subcellular localizations or cluster formation are found in both Gags and are located in equivalent regions of the two proteins. (ii) Regions important for telomere association are present only inHeT-AGag. These are present at several places in the protein, are not redundant, and cannot be complemented intrans. (iii) Regions containing zinc knuckle and major homology region motifs, characteristic of retroviral Gags, are involved in protein-protein interactions of the telomeric Gags, as they are in retroviral Gags.
Unique Pattern of Convergent Envelope Evolution in Simian Immunodeficiency Virus-Infected Rapid Progressor Macaques: Association with CD4-Independent Usage of CCR5
Authors: Dehghani Houman , Puffer Bridget A. , Doms Robert W. , Hirsch Vanessa M. 
Published: May 2003

ABSTRACTThe rate of disease development in simian immunodeficiency virus (SIV) infection of macaques varies considerably among individual macaques. While the majority of macaques inoculated with pathogenic SIV develop AIDS within a period of 1 to 2 years, a minority exhibit a rapid disease course characterized by absence or transience of humoral and cellular immune responses and high levels of virus replication with widespread dissemination of SIV in macrophages and multinucleated giant cells. The goal of this study was to examine viral evolution in three SIVsmE543-3-inoculated rapid progressors to determine the contribution of viral evolution to the development of rapid disease and the effect of the absence of immune pressure upon viral evolution. PCR was used to amplify and clone the entire SIV genome from tissues collected at necropsy, and the course of viral evolution was assessed byenvsequences cloned from sequential plasma samples of one rapid progressor (RP) macaque. The majority of sequence changes in RP macaques occurred in the envelope gene. Substitutions were observed in all three animals at specific conserved residues in envelope, including loss of a glycosylation site in V1/V2, a D-to-N/V substitution in a highly conserved GDPE motif, and a P-to-V/H/T substitution in the V3 loop analog. A cell-cell fusion assay revealed that representativeenvclones utilized CCR5 as a coreceptor, independent of CD4. The selection of specific substitutions in envelope in RP macaques suggests novel selection pressures on virus in such animals and suggests that viral variants that evolve in these animals may play a role in disease progression.
Characterization of a Conformational Epitope on Hepatitis B Virus Core Antigen and Quasiequivalent Variations in Antibody Binding
Authors: Conway J. F. , Watts N. R. , Belnap D. M. , Cheng N. , Stahl S. J. , Wingfield P. T. , Steven A. C. 
Published: May 2003

ABSTRACTWe have characterized a conformational epitope on capsids of hepatitis B virus (HBV) by cryo-electron microscopy and three-dimensional image reconstruction of Fab-labeled capsids to ∼10-Å resolution, combined with molecular modeling. The epitope straddles the interface between two adjacent subunits and is discontinuous, consisting of five peptides—two on one subunit and three on its neighbor. Together, the two icosahedral forms of the HBV capsid—T=3 and T=4 particles—present seven quasiequivalent variants of the epitope. Of these, only three bind this Fab. Occupancy ranges from ∼100 to ∼0%, reflecting conformational variations in the epitope and steric blocking effects. In the former, small shifts of the component peptides have large effects on binding affinity. This approach appears to hold general promise for elucidating conformational epitopes of HBV and other viruses, including those of neutralizing and diagnostic significance.
Molecular and Genetic Determinants of Rous Sarcoma Virus Integrase for Concerted DNA Integration
Authors: Chiu Roger , Grandgenett Duane P. 
Published: May 2003

ABSTRACT
Site-directed mutagenesis of recombinant Rous sarcoma virus (RSV) integrase (IN) allowed us to gain insights into the protein-protein and protein-DNA interactions involved in reconstituted IN-viral DNA complexes capable of efficient concerted DNA integration (termed full-site). At 4 nM IN, wild-type (wt) RSV IN incorporates ∼30% of the input donor into full-site integration products after 10 min of incubation at 37°C, which is equivalent to isolated retrovirus preintegration complexes for full-site integration activity. DNase I protection analysis demonstrated that wt IN was able to protect the viral DNA ends, mapping ∼20 bp from the end. We had previously mapped the replication capabilities of several RSV IN mutants (A48P and P115S) which appeared to affect viral DNA integration in vivo. Surprisingly, recombinant RSV A48P IN retained wt IN properties even though the virus carrying this mutation had significantly reduced integrated viral DNA in comparison to wt viral DNA in virus-infected cells. Recombinant RSV P115S IN also displayed all of the properties of wt RSV IN. Upon heating of dimeric P115S IN in solution at 57°C, it became apparent that the mutation in the catalytic core of RSV IN exhibited the same thermolabile properties for 3′ OH processing and strand transfer (half-site and full-site integration) activities consistent with the observed temperature-sensitive defect for integration in vivo. The average half-life for inactivation of the three activities were similar, ranging from 1.6 to 1.9 min independent of the IN concentrations in the assay mixtures. Wt IN was stable under the same heat treatment. DNase I protection analysis of several conservative and nonconservative substitutions at W233 (a highly conserved residue of the retrovirus C-terminal domain) suggests that this region is involved in protein-DNA interactions at the viral DNA attachment site. Our data suggest that the use of recombinant RSV IN to investigate efficient full-site integration in vitro with reference to integration in vivo is promising.
Cellular Gene Expression Survey of Vaccinia Virus Infection of Human HeLa Cells
Authors: Guerra Susana , López-Fernández Luis A. , Pascual-Montano Alberto , Muñoz Manuel , Harshman Keith , Esteban Mariano 
Published: May 2003

ABSTRACT
Vaccinia virus (VV) is a cytocidal virus that causes major changes in host cell machinery shortly after infecting cells. To define the consequences of virus infection on host gene expression, we used microarrays of approximately 15,000 human cDNAs to examine expression levels of mRNAs isolated at 2, 6, and 16 h postinfection from cultures of infected HeLa cells. The majority of profiling changes during VV infection corresponded to downregulation of genes at 16 h postinfection. Differentially expressed genes were clustered into seven groups to identify common regulatory pathways, with most of them (90%) belonging to clusters 6 and 7, which represent genes whose expression was repressed after infection. Cluster 1, however, contained 37 transcripts (2.81%) showing a robust pattern of induction that was maintained during the course of infection. Genes in cluster 1 included those for Wiskott-Aldrich syndrome protein (WASP) family member WASF1, thymosine, adenosine A2a receptor, glutamate decarboxylase 2, CD-80 antigen, KIAA0888 protein, selenophosphate synthetase, pericentrin, and attractin as well as several expressed sequence tags. We analyzed in more detail the fate of WASP protein in VV-infected cells, because a related family member, N-WASP, is involved in viral motility. WASP protein accumulated in the course of infection; its increase required viral DNA replication and de novo protein synthesis, and it localized in cytoplasmic structures distinct from uninfected cells. This study is the first quantitative analysis of host gene expression following VV infection of cultured human cells, demonstrating global changes in the expression profile, and identifies upregulated genes with potential roles in the virus replication cycle.
Activation of Fusion by the SER Virus F Protein: a Low-pH-Dependent Paramyxovirus Entry Process
Authors: Seth Shaguna , Vincent Annelet , Compans R. W. 
Published: May 2003

ABSTRACT
SER virus, a paramyxovirus closely related to simian virus 5, induces no syncytium formation. The SER virus F protein has a long cytoplasmic tail (CT), and truncation or mutations of the CT result in enhanced syncytium formation (S. Seth, A. Vincent, and R. W. Compans, J. Virol. 77:167-178, 2003; S. Tong, M. Li, A. Vincent, R. W. Compans, E. Fritsch, R. Beier, C. Klenk, M. Ohuchi, and H.-D. Klenk, Virology 301:322-333, 2002). We hypothesized that the presence of the long CT serves to stabilize the metastable conformation of the F protein. We observed that the hemifusion, cytoplasmic content mixing, and syncytium formation ability of the wild-type SER virus F coexpressed with the SER virus hemagglutinin-neuraminidase (HN) protein was enhanced, both qualitatively and quantitatively, at elevated temperatures. We also observed enhanced hemifusion, content mixing, and syncytium formation in SER virus F- and HN-expressing cells at reduced pH conditions ranging between 4.8 and 6.2. We have obtained evidence that in contrast to other paramyxoviruses, entry of SER virus into cells occurs by a low-pH-dependent process, indicating that the conversion to the fusion-active state for SER virus F is triggered by exposure to reduced pH.
Mechanisms of oxidative stress and vascular dysfunction
Authors: Nedeljkovic Z S , Gokce N , Loscalzo J 
Published: May 2003

Abstract
The endothelium regulates vascular homoeostasis through local elaboration of mediators that modulate vascular tone, platelet adhesion, inflammation, fibrinolysis, and vascular growth. Impaired vascular function contributes to the pathogenesis of atherosclerosis and acute coronary syndromes. There is growing pathophysiological evidence that increased generation of reactive oxygen species and oxidative stress participates in proatherogenic mechanisms of vascular dysfunction and atherothrombosis. In this review, the role of oxidative stress in mechanisms of vascular dysfunction is discussed, and potential antioxidant strategies are reviewed.
Effect of Vasoactive Intestinal Peptide and Pituitary Adenylate Cyclase-Activating Polypeptide on Pancreatic, Hepatic and Duodenal Mucosal Bicarbonate Secretion in the Pig
Authors: Glad Henrik , Ainsworth Mark A. , Svendsen Per , Fahrenkrug Jan , Schaffalitzky de Muckadell Ove B. 
Published: May 2003

Background and Method: The potency of pituitary adenylate cyclase-activating polypeptide (PACAP) and the related vasoactive intestinal peptide (VIP) on pancreaticobiliary and duodenal mucosal bicarbonate secretion (DMBS) was studied in anaesthetized pigs. VIP, PACAP27 and PACAP38 were infused at doses of 250, 500, 1,000, 2,000 and 6,000 pmol/kg·h. Results: Infusion of VIP in these concentrations increased the portal plasma concentrations of VIP from 9 to 102, 220, 600, 850 and 3,795 pM, respectively. At doses of 1,000 and 6,000 pmol/kg·h all three peptides significantly stimulated pancreatic bicarbonate secretion, VIP from 0.0 to 0.3 and 7.6 mmol/h, PACAP27 from 0.0 to 2.3 and 8.2 mmol/h, and PACAP38 from 0.0 to 0.2 and 7.4 mmol/h, respectively. Only during infusion of 6,000 pmol/kg·h did the three peptides elicit a significant increase in hepatic bicarbonate output. At this dose VIP increased hepatic bicarbonate output from 0.4 to 3.8 mmol/h, PACAP27 from 0.3 to 3.6 mmol/h, and PACAP38 from 0.1 to 1.4 mmol/h, respectively. Infusion of VIP (500, 1,000, 2,000 and 6,000 pmol/kg·h) dose-dependently and significantly enlarged DMBS from 0.09 to 0.19, 0.41, 0.54 and 0.53 mmol/h, respectively. A significant effect of PACAP27 and PACAP38 on DMBS was only obtained at a dose of 6,000 pmol/kg·h, and at this dose VIP-induced DMBS was 4- and 8-fold higher than that induced by PACAP27 and PACAP38, respectively. Conclusions: VIP, PACAP27 and PACAP38 all have a pharmacological effect on both DMBS and pancreaticobiliary bicarbonate secretion. When comparing these results with the distribution of VIP/PACAP neurons and relevant receptors, it seems likely that VIP and PACAP have a physiological importance as neurotransmitters in the pancreas and duodenum, but not in the liver. The differences in the effect of VIP and PACAP on DMBS observed in this study indicate that there are variations between pancreatic and duodenal PACAP/VIP receptor subtypes, or that the duodenal inactivation of the peptides is different from the inactivation in the pancreas.
Experimental Trigeminal Glycerol Injection in Dogs: Histopathological Evaluation by Light and Electron Microscopy
Authors: Işik N. , Pamir M.N. , Benli K. , Erbengi A. , Erbengi T. , Ruacan Ş. 
Published: May 2003

We investigated the effects of percutaneous gasserian glycerol injection in dogs and reviewed the histopathological changes. Experiments were performed in 16 adult healthy mongrel dogs. In group 1 (8 dogs) normal saline and in group 2 (8 dogs) pure glycerol was injected in the right trigeminal ganglion. After these procedures, dogs in each group were sacrificed after 24 h (3 dogs), 7 days (3 dogs), 21 days (2 dogs). The trigeminal ganglion and nerve of both sides were removed by using microsurgical techniques and examined by light and electron microscopy. Group 1: in all sections, nerve cells, myelinated and nonmyelinated fibers revealed normal patterns with slight fibrosis. Group 2: in all sections, myelinated fibers showed disintegration and swelling of the myelin sheath, rupture of axon continuity, destruction of basal lamina, deformation of the myelin-axon relationship by both light microscopy and electron microscopy. The sections examined by electron microscopy also showed axonolysis in nonmyelinated fibers. The changes after 7 and 21 days were less prominent than after 24 h. In the left sides, there are no pathological changes. Glycerol has a neurolytic effect on the dog’s trigeminal ganglion. These effects were not specific and selective for myelinated and nonmyelinated nerve fibers.
Consolidation Docetaxel After Concurrent Chemoradiotherapy in Stage IIIB Non–Small-Cell Lung Cancer: Phase II Southwest Oncology Group Study S9504
Authors: Gandara David R. , Chansky Kari , Albain Kathy S. , Leigh Bryan R. , Gaspar Laurie E. , Lara Primo N. , Burris Howard , Gumerlock Paul , Kuebler J. Philip , Bearden James D. , Crowley John , Livingston Robert 
Published: May 2003

Purpose: To test the concept of taxane sequencing in combined-modality therapy, this phase II trial (S9504) evaluated consolidation docetaxel after concurrent chemoradiotherapy in patients with pathologically documented stage IIIB non–small-cell lung cancer (NSCLC). Results were compared with those of the predecessor study (S9019) with identical eligibility, staging criteria, and treatment, excepting docetaxel consolidation. Patients and Methods: Treatment consisted of cisplatin 50 mg/m2 on days 1, 8, 29, and 36, etoposide 50 mg/m2 on days 1 through 5 and 29 through 33, and concurrent thoracic radiotherapy (total dose of 61 Gy). Consolidation docetaxel started 4 to 6 weeks after chemoradiotherapy at an initial dose of 75 mg/m2. Results: Stage subsets (tumor-node-metastasis system) in 83 eligible patients were as follows: T4N0/1, 31 patients (37%); T4N2, 22 patients (27%), and T1–3N3, 30 patients (36%). Concurrent chemoradiotherapy was generally well tolerated, but two patients died from probable radiation-associated pneumonitis. Neutropenia during consolidation docetaxel was common (57% with grade 4) and most frequent during escalation to 100 mg/m2. Median progression-free survival was 16 months, median survival was 26 months, and 1-, 2-, and 3-year survival rates were 76%, 54%, and 37%, respectively. Brain metastasis was the most common site of failure. In S9019, median survival was 15 months and 1-, 2-, and 3-year survival rates were 58%, 34%, and 17%, respectively. Conclusion: Consolidation docetaxel after concurrent chemoradiotherapy in stage IIIB NSCLC is feasible and generally tolerable, and results compare favorably with the predecessor trial S9019. Nevertheless, this study remains hypothesis-generating and does not provide definitive evidence of the benefit of this approach. Phase III trials evaluating the S9504 regimen have been initiated to validate these results.
Molecular Grading of Urothelial Cell Carcinoma With Fibroblast Growth Factor Receptor 3 and MIB-1 is Superior to Pathologic Grade for the Prediction of Clinical Outcome
Authors: van Rhijn Bas W.G. , Vis André N. , van der Kwast Theo H. , Kirkels Wim J. , Radvanyi François , Ooms Engelbert C.M. , Chopin Dominique K. , Boevé Egbert R. , Jöbsis Adriaan C. , Zwarthoff Ellen C. 
Published: May 2003

Purpose: Fibroblast growth factor receptor 3 (FGFR3) mutations were recently found at a high frequency in well-differentiated urothelial cell carcinoma (UCC). We investigated the relationship between FGFR3 status and three molecular markers (MIB-1, P53, and P27kip1) associated with worse prognosis and determined the reproducibility of pathologic grade and molecular variables. Patients and Methods: In this multicenter study, we included 286 patients with primary (first diagnosis) UCC. The histologic slides were reviewed. FGFR3 status was examined by polymerase chain reaction–single strand conformation polymorphism and sequencing. Expression levels of MIB-1, P53, and P27kip1 were determined by immunohistochemistry. Mean follow-up was 5.5 years (range, 0.4 to 18.4 years). Results: FGFR3 mutations were detected in 172 (60%) of 286 UCCs. Grade 1 tumors had an FGFR3 mutation in 88% of patient samples and grade 3 tumors in 16% of patient samples. Conversely, aberrant expression patterns of MIB-1, P53, and P27kip1 were seen in 5%, 2%, and 3% of grade 1 tumors and in 85%, 60%, and 56% of grade 3 tumors, respectively. In multivariate analysis with recurrence rate, progression, and disease-specific survival as end points, the combination of FGFR3 and MIB-1 proved independently significant in all three cases. By using these two molecular markers, three molecular grades (mGs) could be identified: mG1 (mutation; normal expression), favorable prognosis; mG2 (two remaining combinations), intermediate prognosis; and mG3 (no mutation; high expression), poor prognosis. The molecular variables were more reproducible than pathologic grade (85% to 100% v 47% to 61%). Conclusion: The FGFR3 mutation represents the favorable molecular pathway of UCC. Molecular grading provides a new, simple, and highly reproducible tool for clinical decision making in UCC patients.