bluuebunny/crossref_metadata_2025_split huggingface dataset:
Modulation of coronavirus‐mediated cell fusion by homeostatic control of cholesterol and fatty acid metabolism
Authors: Cervin Marguerite , Anderson Robert 
Published: March 2007

AbstractCellular susceptibility to fusion mediated by murine coronavirus (mouse hepatitis virus, MHV strain A59) was separated into lipid‐dependent and lipid‐independent mechanisms with the use of subclones and selected mutants of mouse L‐2 fibroblasts. Fusion‐resistant L‐2 cell mutants had similar cholesterol and fatty acid composition as did their fusion‐susceptible parent subclone, and were presumably deficient in a genetically mutable non‐lipid, host cell factor (e.g., fusion protein receptor). On the other hand, cellular sensitivity to virus fusion, which is known to be influenced by cell cholesterol content [Daya et al., 1988], was shown further to be modulated by homeostatic alterations in fatty acid metabolism. Cholesterol supplementation of mouse L‐2 fibroblasts or of peritoneal macrophages from MHV‐susceptible mice elevated susceptibility to viral fusion. Increased fusion susceptibility occurred in cholesterol‐supplemented L‐2 cells in the absence of any detectable alterations i n host cell fatty acid composition, thus demonstrating fusion enhancement by cholesterol alone. L‐2 cells cloned by limiting dilution in normal (not cholesterol‐supplemented) medium were found to be heterogeneous i n cholesterol content. Interestingly, high cholesterol‐containing subclones had increased levels of C‐18:0, C‐18:2, C‐20:4, and C‐22:6 and markedly reduced levels of C‐18:l fatty acids when compared to low cholesterol‐containing subclones. High cholesterol‐containing subclones did not show enhanced susceptibility to viral fusion, suggesting that homeostatic alteration of fatty acid metabolism compensated for the increased cholesterol levels and countered the normally fusion‐enhancing effect of cholesterol alone. Since these observations have potentially important consequences regarding the effects of dietary cholesterol on the severity of virus infection, we examined liver titres and pathology of normal and hypercholesterolemic mice infected with MHV. Hypercholesterolemia had no significant effect on virus replication or on liver pathology in two MHV‐ sensitive strains (Balb/c and AIJ) or in one MHV‐resistant (SJLIJ) of mice. Lipid analyses of the livers from normal and hypercholesterolemic mice showed evidence of two homeostatic mechanisms (cholesterol esterification and alteration of fatty acid composition) which likely counteracted the normally exacerbating effect of cholesterol on MHV cytopathology.
Antibody to hepatitis C virus in cryptogenic chronic liver disease
Authors: Diodati G. , Tagger A. , Bonetti P. , Ribero M. L. , Drago C. , Cavalletto D. , Grossi A. , Realdi G. , Ruol A. , Alberti A. 
Published: March 2007

AbstractThe prevalence of antibody to hepatitis C virus (HCV) was studied in 207 patients with chronic liver disease of unknown etiology, in relation to clinical, epidemiological and histological features. Serum antibody to C‐100 epitope of HCV was detected by ELISA in 82.6% of patients, with a significant difference compared with a group of patients with primary biliary cirrhosis (10%). The presence of anti‐HCV antibody in serum did not correlate with age, sex, histological diagnosis, and activity and duration of the disease, nor with serum anti‐HBc, used as a marker of exposure to hepatitis B virus infection. These results strongly support the view that most cases that were previously defined as cryptogenic forms of chronic liver disease are in fact related to HCV infection. There was a correlation between serum anti‐HCV antibody and history of risk for parenteral exposure or of acute hepatitis. This correlation was particularly evident for transmission by parenteral route, suggesting that HCV infection may be transmitted often by this route (36.8% among anti‐HCV antibody‐positive patients and 11.1% among anti‐HCV‐negative patients). Liver disease in patients without risk factors for parenteral transmission and with lower prevalence of anti‐HCV antibody may be caused by other as yet unidentified non‐A, non‐B (non‐C) agents or may be of nonviral origin.
Growth of human immunodeficiency virus I in cultured cells in the absence of the CD4 antigen
Authors: Morrison N. K. , McCarthy K. , Hart C. A. 
Published: March 2007

AbstractThe ability of a variety of epithelial, embryonal, placental, and neuronal cells to express the CD4 antigen and to be infected by human immuno deficiency virus 1 (HIV‐1) was examined. Only two (IMR‐32 and HeLa‐T4) expressed CD4 detectable by indirect immunofluorescence, and both were infectable by HIV‐1. Two others, a human laryngeal carcinoma (HEp‐2) and human colonic carcinoma (HT‐291, did not express CD4 antigen but were infectable by HIV‐I. Infection of the HEp‐2 cells was detectable four months (and 20 serial passages) later. Infection of HEp‐2 cells was not inhibited by anti CD4 monoclonal anti‐ body but was by the lectin concanavalin A. These results suggest the presence of a receptor other than CD4 can be involved in HIV‐1 infection.
Comparison of class and subclass antibody response to live and UV‐inactivated RSV administered intranasally in mice
Authors: Reuman Peter D. , Keely Scott P. , Schiff Gilbert M. 
Published: March 2007

AbstractTo determine the effect of viral dose and replication on the subclass antibody response to RSV, mice were immunized intranasally with different doses of live RSV (104‐106 pfu) and compared to mice given an immunizing regimen of UV‐inactivated RSV. Mice given the 106 pfu dose of live RSV and mice given the 40 p.g dose of UV‐inactivated RSV had comparable class specific antibody responses to whole RSV in serum and respiratory secretions. Serum from these two groups of mice were then compared for IgG subclass response to whole RSV. A predominance of IgG2a subclass antibody was found for both immunizing regimens, and no significant differences in subclass proportions were noted between regimens. These two regimens were then compared for serum total IgG response to RSV surface glycoproteins F and G. The serum IgG response to these glycoproteins was lower after immunization with UV‐ inactivated RSV than after live‐RSV immunization (F: P = 0.03; G: P < 0.051, even though the serum IgG response of the two groups to whole RSV was comparable. The IgG subclass re‐ sponse to surface glycoproteins was evaluated for live RSV immunization. The proportions of subclass antibody responses to glycoprotein F were comparable to the subclass response proportions to whole RSV and were not characteristic of a T‐dependent response pattern. The subclass profile for glycoprotein G was not com‐ parable to that of whole RSV but was suggestive of a T‐independent response pattern.
Direct serotyping of porcine rotaviruses using VP7‐specific monoclonal antibodies by an enzyme immunoassay
Authors: Nagesha H. S. , Holmes I. H. 
Published: March 2007

AbstractEmploying a serotyping EIA test using Mabs both cell culture adapted and faecal porcine rotaviruses were classified into serotypes G3, G3/5, G4, and G5. The MAbs have confirmed and extended the serotyping results obtained using polyclonal antisera. These MAbs are therefore potential reagents for serotyping of porcine ro‐taviruses. Using subgroup specific MAbs sero‐types G3, G3/5, and G5 were found to contain subgroup I antigens while G4 rotaviruses contained either subgroup II or subgroup I antigens.
Simple system for isolation of cellular and viral mutants for transformation by retrovirus
Authors: Inoue Hirokazu , Isaka Masami , Takeda Shun‐Ichi , Hakura Akira 
Published: March 2007

AbstractTo investigate the cellular mechanism of transformation by retroviruses, we established a system for isolation of cellular and viral mutants for transformation of a rat cell line. Mutagenized untransformed cells of this line were infected with recombinant murine retrovirus containing the src gene of Rous sarcoma virus and the selective marker gene, neo. After reaching confluence, cells transformed by the src gene tend to overgrow and die. Utilizing this property of src transformed rat cells and the selective marker gene, we could easily select untransformed cell clones containing the retrovirus genome. Expression of the src gene product in the flat clones selected was examined by in vitro assay of src kinase activity. To determine whether the mutations of these flat clones were viral or cellular, the susceptibilities of the clones to transformation were examined after superinfection with the wild‐type virus and also characterized the retroviruses recovered from these clones. With this system, two novel clones were isolated. One had a defect in viral information affecting the transformed phenotype, but still retained src kinase activity like fully transformed cells. The other showed low src kinase activity but retained wild‐type transforming virus, suggesting that a cellular gene involved in viral gene expression was mutated.
Hepatitis C virus RNA in blood donor sera detected by the polymerase chain reaction: Comparison with supplementary hepatitis C antibody assays
Authors: Widell Anders , Månsson Ann‐Sofie , Sundstrom Gunnar , Hansson Bengt Göran , Nordenfelt Erik 
Published: March 2007

AbstractThe low specificity of screening ELISAs for antibodies to hepatitis C virus in blood donors has called for confirmatory tests. Two types of supplementary antibody assays are available, recombinant immunoblot assays (RIBA‐1 and RIBA‐2) and an antibody consumption test referred to as a neutralization assay. Amplification of viral nucleic acid by the polymerase chain reaction (PCR) provides an antibody independent mode of detecting viral infection. We applied reverse transcription‐double PCR to detect an HCV 5'‐noncoding viral RNA sequence in serum specimens and compared PCR findings with confirmatory antibody tests. This study includes sera from 37 blood donors found positive by the Ortho anti‐HCV (C100‐3) ELISA out of 14,591 donations. Of the 37 positive sera, 8 were positive by RIBA‐1 and 1 further by RIBA‐2. Seven of the RIBA positive sera contained HCV RNA by PCR. Among the 8 indeterminate and the 21 negative donor sera by RIBA‐I, no PCR positive serum was found. The 37 anti‐HCV positive donor sera identified by Ortho ELISA were also tested by Abbott anti‐HCV (C100‐3) ELISA whereby 22 were positive. Of these 22 sera plus 1 further with ELISA OD just below cutoff, 8 were positive by the “neutralization assay,” (Abbott Laboratories, North Chicago, IL, USA) and 6 of these, including the borderline serum, were PCR positive. One of the two neutralizable but PCR negative sera was RIBA positive and the other was indeterminate. However, one ELIS. A (Abbott Laboratories) positive (OD 1.99) serum was not neutralizable but nevertheless contained HCV RNA by PCR. Thus in blood donor sera, anti‐HCV (C100‐3) reactivity confirmed by RIBA or “neutralization” correlated well with the presence of HCV RNA.
Host dependent modulation of hepatitis delta virus replication in chronic delta hepatitis
Authors: Gupta Sanjeev , Govindarajan Sugantha , Valinluck Boontar , Redeker Allan G. 
Published: March 2007

AbstractTo determine whether host dependent differences modulated hepatitis delta virus replication in chronic delta hepatitis, we tested HDV RNA in homosexual and intravenous drug abuser populations. Overall, the seroprevalence of HDV RNA in the two groups with matching clinical characteristics was 72% (76/106 patient visits). A trend for greater prevalence of HDV RNA was noted at initial presentation in homosexuals (82%) compared to intravenous drug abusers (6O%, P < 0.05) and this trend appeared to be maintained during two years of sequential follow‐up. The seroprevalence of co‐appearing IgM and IgG anti‐HD antibodies was similar in the two groups of patients. However, in HDV RNA positive homosexuals IgG anti‐HD antibody was more prevalent, and additionally, assumed concordance with HDV RNA of 92% although the significance of this observation is unclear. The difference in prevalence of HIV in the two groups did not reach statistical significance. Prospective studies are required to confirm differences in HDV replication in various patient groups and to define underlying mechanisms.
Levels of Pre‐S antigens and HBV DNA in sera from high and low viremic HBV carriers
Authors: Garbuglia Anna Rosa , Manzin Aldo , Budkowska Agata , Taliani Gloria , Clementi Massimo , Delfini Carlo , Carloni Guido 
Published: March 2007

AbstractThe biological and clinical significances of pre‐S antigens and HBV replication were investigated. Some 125 sera, 28 from HBeAg and 97 from anti‐HBe‐positive HBsAg, carriers were studied. The aim was to verify whether pre‐S antigens could be expressed in serum in complete absence of viremia. Pre‐S proteins, determined by an enzyme immunoassay, were found in sera regardless of the presence of HBV DNA, as detected by spot‐hybridization. The sera without detectable HBV DNA were investigated further by PCR using specific primers for the S and C regions of HBV. PCR analysis of samples revealed that 4 out of 5 HBeAg and 33 out of 41 (80.5%) anti‐HBe positive sera contained HBV amplified sequences of S and C regions. Pre‐S antigen values correlated well with the amounts of HBV DNA in serum detected by PCR in anti HBe‐positive subjects with high titers of pre‐S antigens (104−106). In addition, PCR highlighted the presence of HBV DNA sequences in 8 out of 17 (47.1%) pre‐S‐negative HBsAg‐positive sera.
Perinatal infection by human immunodeficiency virus type 1 (HIV–1): Relationship between proviral copy number in vivo, viral properties in vitro, and clinical outcome
Authors: De Rossi Anita , Pasti Marcella , Mammano Fabrizio , Ometto Lucia , Giaquinto Carlo , Chieco‐Bianchi Luigi 
Published: March 2007

AbstractHuman immunodeficiency virus type 1 (HIV‐1) isolates from 25 perinatally HIV‐1 infected children were classified according to their capacity to replicate in vitro as rapid (R), intermediate (S/R) and slow (S) variants. R‐type viruses replicated on peripheral blood mononuclear cells (PBMCs) and grew better in T‐lymphoid cells, even though 9 out of 12 isolates also maintained tropism for monocytoid cells. The S/R‐type isolates replicated efficiently after several days of culture, while the S‐type viruses displayed only a low and transient replication activity; however, both S/R‐ and S‐type isolates exerted viral transactivation activity in an indicator monocytoid cell line. Replication patterns in vitro were significantly associated in vivo with the number of HIV‐1 copies in PBMCs as determined by polymerase chain reaction: in children with R‐type isolates, the number of HIV‐1 proviral DNA molecules/105 PBMCs ranged from 62 to 571, and in children with S/R and S isolates the range was 5–43.Seven children had severe symptomatic HIV‐1 infection, and in all an R‐type virus was identified; 18 children had no or only mild symptoms, and among these, S‐, S/R‐, and R‐type isolates were found in 5, 8, and 5 cases, respectively. Besides demonstrating HIV‐1 variability in perinatal infection, these findings suggest that R‐type virus might be a prerequisite for disease progression.
Surrogate markers are not useful for identification of HCV carriers in chronic hemodialysis patients
Authors: Willems M. , De Jong G. , Moshage H. , Verresen L. , Goubau P. , Desmyter J. , Yap S. H. 
Published: March 2007

AbstractSeveral diagnostic hepatitis C assays have been developed for the detection of antibodies to different antigens of the virus. This virus is the major cause of non‐A, non‐B hepatitis. Seventynine patients undergoing chronic hemodialysis and/or hemofiltration were tested for the presence of anti‐HCV antibodies (anti‐C‐100‐3 antibodies and anti‐core antibodies), anti‐hepatitis B core antibodies (anti‐HBc), and aminotransferases (ALT). Seven patients were positive by one or more of the anti‐HCV enzyme linked immunoassays (EIAs), while HCV‐RNA was detectable in only four patients. These four patients had at least one, but not necessarily the same, positive anti‐HCV EIA. HCV‐RNA was not detected in patients who had no antibodies as determined by all six anti‐HCV EIAs. All patients with a marker for HCV infection had persistent normal levels of transaminases. Three patients had elevated ALT values without a marker for HCV infection and suffered from hepatitis B virus infection. Anti‐HBc was detected in 27/72 patients without any marker and in four patients with a marker of HCV infection. However, HCV‐RNA was detectable in only one of these four anti‐HBc positive patients. It is concluded that surrogate markers (anti‐HBc and serum transaminases) are not useful for identification of HCV carriers in chronic hemodialysis patients.
Occurrence and characterization of acyclovir‐resistant herpes simplex virus isolates: Report on a two—year sensitivity screening survey
Authors: Nugier F. , Colin J. N. , Aymard M. , Langlois M. 
Published: March 2007

AbstractFor the past 2 years, a survey network was established for the screening of acyclovir (ACV)‐resistant clinical isolates of herpes simplex virus (HSV). Among 889 strains tested for in vitro ACV sensitivity, 14 HSV‐1 and 6 HSV‐2 were resistant to ACV concentrations exceeding 3 μg/ml. These resistant isolates were most often obtained after prolonged ACV treatment of severely immuno‐compromised patients. For five patients, the emergence of ACV‐resistant virus correlated with treatment failure. In particular, a decrease in the in vitro sensitivity to ACV was observed for eight successive HSV‐1 isolates from one immunodeficient patient undergoing therapy. All ACV‐resistant isolates were studied for their sensitivity to different antiherpetic compounds and showed various cross‐sensitive and ‐resistant patterns. The examination of viral populations by plaque autoradiography procedures frequently revealed their heterogeneity in terms of thymidine kinase (TK) phenotype and allowed the detection of various proportions of TK‐positive (TK+), TK‐deficient (TKD), or TK‐altered (TKA) viruses. Our data underline the importance of monitoring the emergence of drug‐resistant virus during the course of antiviral therapy, and the need for the detection and characterization of TK mutants in clinical specimens. The routine examination of drug sensitivity of HSV isolates provides useful information to clinicians for the management of ACV treatment in the hope of preventing ACV‐resistant mutants from becoming predominant in mixed viral populations.
Significance of serum IgM anti‐HBc in chronic hepatitis B virus infection
Authors: Smith Hather. M. , Lau Johnson Y. N. , Davies Susan E. , Daniels Helena M. , Alexander Graeme J. M. , Williams Roger 
Published: March 2007

AbstractBecause of widely differing reports on the significance of IgM anti‐HBc in chronic hepatitis B virus (HBV) infection, paired sera and liver biopsies from 49 patients with chronic HBV infection were analysed for serum IgM anti‐HBc, HBsAg titre, HBeAgianti‐HBe, HBV DNA, serum aspartate transaminase, intrahepatic HBcAg expression, and liver histology. High levels of IgM anti‐HBc, i n the diagnostic range of acute hepatitis B (>1.2), were detected in seven patients (14.3%) and a total of 34 patients (69.6%) had an index of more than 0.2. No correlation was found between IgM anti‐HBc and the serum markers of active viral replication or HBsAg titre but it correlated significantly with intrahepatic expression of cytoplasmic HBcAg (r2 = 0.165, P =0.002). IgM anti‐HBc also correlated with active liver histology (P = 0.015) but there was a considerable overlap of the IgM anti‐HBc index values between the various disease groups, indicating a poor specificity. Serial assessment of IgM anti‐HBc in eight patients treated with interferon‐α (four responders) showed an increase in IgM anti‐HBc in three out of four patients corresponding to the e‐seroconversion period followed by a drop in IgM anti‐HBc levels. However, an increase in IgM anti‐HBc was also seen in one non‐responder, indicating that this feature is not unique to interferon‐α responders. These data indicate that serum IgM anti‐HBc cannot be used alone as a certain diagnostic measure of HBV replication nor in the prediction of liver histology.
Comparison of hepatitis B virus subtyping of d/y determinants by radioimmunoprecipitation assay and the polymerase chain reaction
Authors: Nicholson W. J. , Black S. H. , Simmonds P. , Chung C‐W. , Aw D. , Peutherer J. F. 
Published: March 2007

AbstractUsing a double polymerase chain reaction a method was devised for detecting and subtyping hepatitis B virus DNA in serum samples. Primers from the S‐gene were selected from the sequence analyses of five HBV HBsAg subtypes, to amplify HBV DNA and subtype for y specific DNA. Thirty‐eight samples were subtyped for dand y determinants by radioimmunoprecipitation assay (RIPA) and the polymerase chain reaction (PCR). Subtyping by PCR and RIPA was in agreement in 100°/o of subtype y samples and 83.3% of subtype d, giving an overall correlation of 92.1%. As a third comparison, 12 amplified samples were digested by the restriction enzyme Sau 3A, which differentiates between subtypes yand d. The digest results agreed with PCR in 83.3% of the samples. In addition, we compared our standard phenol/chloroform extraction against a rapid one step method. The phenol/chloroform stage was found to be essential for the removal of nucleases and polymerase inhibitors present in sera.
The diagnostic significance of the polymerase chain reaction and isoelectric focusing in herpes simplex virus encephalitis
Authors: Pohl‐Koppe Annette , Dahm Cornelia , Elgas Michael , Kühn Joachim E. , Braun Rüdiger W. , Meulen Volker te. 
Published: March 2007

AbstractIn this study, serum and CSF samples of 55 neurological patients have been examined to confirm the diagnosis of herpes simplex virus encephalitis (HSVE). Different methods were applied, including serological titer evaluations, determination of intrathecally‐produced HSV‐specific antibodies by isoelectric focusing with affinity immunoblotting (IEF), as well as HSV‐specific ELISA and HSV‐specific polymerase chain reaction (PCR). The results of IEF and PCR have been compared and contrasted to develop general directions for virological diagnosis of HSVE. Of 14 patients suffering from clinically diagnosed HSVE, HSVE was confirmed in 12 cases by the demonstration of PCR or IEF positivity. A HSV‐specific CNS infection could be excluded in 2 of these 14 patients. In 17 patients suffering from non‐HSVE, PCR and IEF results were negative. Twenty‐four patients, suffering from other neurological diseases, serving as a control group, were PCR‐ and HSV‐IEF‐negative. The study indicated that there are two possibilities for unequivocal demonstration of HSV‐specific CNS involvement: first, performance of PCR especially in the acute phase of disease and in sus‐picious relapses, and second, performance of HSV‐specific IEF for determination of intrathecally synthesized HSV‐specific antibodies. It is suggested that these two methods should be introduced in routine diagnosis of viral encephalitis.
Herpes simplex virus infection of cultured human term trophoblast
Authors: Nørskov‐Lauritsen N. , Aboagye‐Mathisen G. , Juhl C. B. , Petersen P. M. , Zachar V. , Ebbesen P. 
Published: March 2007

AbstractMononuclear trophoblast cells were isolated from term placentas of uncomplicated pregnancies, purified to homogeneity by negative immunomagnetic separation using monoclonal antibodies to the major histocompatibility complex, and challenged with herpes simplex virus (HSV). The cultures were highly susceptible to virusinduced cytopathic effect as evidenced by cytopathic alteration and inhibition of human chorionic gonadotropin (hCG) secretion. Both HSV I and II underwent a full replicative cycle in the trophoblast, although the production of progeny virus was 10‐100 times less than that obtained with placental fibroblasts or choriocarcinoma cells. The permissiveness was independent of in vitro syncytial differentiation of the trophoblast. The results suggest that the trophoblast layer may be involved in intrauterine HSV infection.