bluuebunny/crossref_metadata_2025_split huggingface dataset:
Complex Formation by Human Cytomegalovirus Glycoproteins M (gpUL100) and N (gpUL73)
Authors: Mach M. , Kropff B. , Dal Monte P. , Britt W. 
Published: July 2002

ABSTRACT

The envelope glycoproteins of human cytomegalovirus (HCMV) virions are incompletely characterized. We have analyzed complex formation between glycoprotein M (gM or gpUL100) and a second glycoprotein. gM-homologous proteins are conserved throughout the herpesvirus family and represent type III membrane proteins containing multiple hydrophobic sequences. In extracellular HCMV particles, gM was found to be complexed through disulfide bonds to a second protein with an apparent molecular mass of 50 to 60 kDa. The 50- to 60-kDa protein was found to be derived from reading frame UL73 of HCMV strain AD169. UL73-homologous genes are also conserved within herpesviruses. When transiently expressed by itself, the UL73 gene product consisted of a protein of 18 kDa. However, in the presence of gM, the UL73 gene product was posttranslationally modified to the 50- to 60-kDa species. Thus, gM and the UL73 gene product, which represents the gN homolog of herpesviruses, form a disulfide-linked complex in HCMV virions. Transient expression of gM and gN followed by fluorescence imaging with monoclonal antibodies against either protein demonstrated that complex formation was required for transport of the proteins from the endoplasmic reticulum to the Golgi and
trans
-Golgi compartments. Finally, we tested the gM-gN complex for reactivity with sera from HCMV-seropositive donors. Whereas most sera failed to react with either gM or gN when expressed alone, 62% of sera were positive for the gM-gN complex. Because a murine monoclonal antibody reactive with gN in the gM-gN complex efficiently neutralizes infectious virus, the gM-gN complex may represent a major antigenic target of antiviral antibody responses.
Multiple Integrations of Human Foamy Virus in Persistently Infected Human Erythroleukemia Cells
Authors: Meiering Christopher D. , Comstock Kenine E. , Linial Maxine L. 
Published: July 2002

ABSTRACT

Foamy viruses are complex retroviruses whose replication strategy resembles that of conventional retroviruses. However, foamy virus replication also resembles that of hepadnaviruses in many respects. Because hepadnaviruses replicate in an integrase-independent manner, we were interested in investigating the characteristics of human foamy virus (HFV) integration. We have shown that HFV requires a functional integrase protein for infectivity. Our analyses have revealed that in single-cell clones derived from HFV-infected erythroleukemia-derived cells (H92), there were up to 20 proviral copies per host cell genome as determined by Southern blot and fluorescent in situ hybridization analysis. Use of specific probes has also shown that a majority of the proviruses contain the complete
tas
gene, which encodes the viral transactivator, and are not derived from Δ
tas
cDNAs, which have been shown to arise rapidly in infected cells. To demonstrate that the multiple proviral sequences are due to integration instead of recombination, we have sequenced the junctions between the proviral sequences and the host genome and found that the proviruses have authentic long terminal repeat ends and that each integration is at a different chromosomal site. A virus lacking the Gag nuclear localization signal accumulates fewer proviruses, suggesting that nuclear translocation is important for high proviral load. Since persistently infected H92 clones are not resistant to superinfection, the relative importance of an intracellular versus extracellular mechanism in proviral acquisition has yet to be determined.
Induction of the Cellular E2F-1 Promoter by the Adenovirus E4-6/7 Protein
Authors: Schaley Joel , O'Connor Robert J. , Taylor Laura J. , Bar-Sagi Dafna , Hearing Patrick 
Published: July 2002

ABSTRACT
The adenovirus type 5 (Ad5) E4-6/7 protein interacts directly with different members of the E2F family and mediates the cooperative and stable binding of E2F to a unique pair of binding sites in the Ad5 E2a promoter region. This induction of E2F DNA binding activity strongly correlates with increased E2a transcription when analyzed using virus infection and transient expression assays. Here we show that while different adenovirus isolates express an E4-6/7 protein that is capable of induction of E2F dimerization and stable DNA binding to the Ad5 E2a promoter region, not all of these viruses carry the inverted E2F binding site targets in their E2a promoter regions. The Ad12 and Ad40 E2a promoter regions bind E2F via a single binding site. However, these promoters bind adenovirus-induced (dimerized) E2F very weakly. The Ad3 E2a promoter region binds E2F very poorly, even via a single binding site. A possible explanation of these results is that the Ad E4-6/7 protein evolved to induce cellular gene expression. Consistent with this notion, we show that infection with different adenovirus isolates induces the binding of E2F to an inverted configuration of binding sites present in the cellular E2F-1 promoter. Transient expression of the E4-6/7 protein alone in uninfected cells is sufficient to induce transactivation of the E2F-1 promoter linked to chloramphenicol acetyltransferase or green fluorescent protein reporter genes. Further, expression of the E4-6/7 protein in the context of adenovirus infection induces E2F-1 protein accumulation. Thus, the induction of E2F binding to the E2F-1 promoter by the E4-6/7 protein observed in vitro correlates with transactivation of E2F-1 promoter activity in vivo. These results suggest that adenovirus has evolved two distinct mechanisms to induce the expression of the E2F-1 gene. The E1A proteins displace repressors of E2F activity (the Rb family members) and thus relieve E2F-1 promoter repression; the E4-6/7 protein complements this function by stably recruiting active E2F to the E2F-1 promoter to transactivate expression.
Hypervariable Region 1 Sequence Stability during Hepatitis C Virus Replication in Chimpanzees
Authors: Ray Stuart C. , Mao Qing , Lanford Robert E. , Bassett Suzanne , Laeyendecker Oliver , Wang Yu-Ming , Thomas David L. 
Published: July 2002

ABSTRACT
The putative envelope 2 (E2) gene of hepatitis C virus (HCV) contains a highly variable region referred to as hypervariable region 1 (HVR1). We hypothesized that this genetic variability is driven by immune selection pressure, rather than representing the accumulation of random mutations in a region with relatively little functional constraint. To test this hypothesis, we examined the E2 sequence of a human inoculum that was passaged through eight chimpanzees, which appear to have a replicative rate (opportunity for chance mutation) similar to that of humans. Acute-phase plasma samples from a human (the inoculum) and six of eight serially infected chimpanzees were studied. For each, 33 cloned cDNAs were examined by a combined heteroduplex–single-stranded conformational polymorphism assay to assess quasispecies complexity and optimize selection of clones with unique gel shift patterns (clonotypes) for sequencing. The sequence diversity of HCV was significantly lower in the chimpanzees than in the humans, and during eight serial passages there was no change in the sequence of the majority clonotype from each animal examined. Similarly, the rates of protein sequence altering (nonsynonymous) substitution were lower in the chimpanzees than in the humans. These findings demonstrate that nonsynonymous mutations indicate selection pressure rather than being an incidental result of HCV replication.
Identification of Antigenic Proteins Encoded by Human Herpesvirus 8 and Seroprevalence in the General Population and among Patients with and without Kaposi's Sarcoma
Authors: Katano Harutaka , Iwasaki Takuya , Baba Nobuyoshi , Terai Masanori , Mori Shigeo , Iwamoto Aikichi , Kurata Takeshi , Sata Tetsutaro 
Published: July 2002

ABSTRACT

To establish a sensitive and specific antibody assay, potent antigenic proteins encoded by human herpesvirus 8 (HHV8) were studied. Fifteen recombinant HHV8-encoded proteins were produced as glutathione
S
-transferase fusion proteins. The sera from AIDS-associated Kaposi's sarcoma (KS) patients reacted with four proteins encoded by open reading frames (ORFs) K8.1, 59, 65, and 73 in a Western blot assay. An enzyme-linked immunosorbent assay (ELISA) using these four proteins as antigens (mixed-antigen ELISA) revealed that all 26 sera derived from KS patients (24 with and 2 without human immunodeficiency virus infection) became positive for anti-HHV8 antibodies. The presence of HHV8 was demonstrated in 14 (1.4%) of 1,004 sera from the Japanese general population and 10 (1.9%) of 527 sera from patients without HHV8-associated diseases. The presence of immunoglobulin G (IgG) and IgM antibodies against HHV8 examined further by the mixed-antigen ELISA and Western blotting revealed IgG antibody in all ELISA-positive sera, while IgM antibody against ORF K8.1 was absent. These data suggest that the ORF 73 and 65 proteins are potent antigens for a sensitive serological assay.
Sustained Activation of Mitogen-Activated Protein Kinases and Activator Protein 1 by the Hepatitis B Virus X Protein in Mouse Hepatocytes In Vivo
Authors: Nijhara Ruchika , Jana Siddhartha S. , Goswami Shyamal K. , Rana Ajay , Majumdar Subeer S. , Kumar Vijay , Sarkar Debi P. 
Published: July 2002

ABSTRACT
Transcriptional activation of diverse cellular genes by the X protein (HBx) of hepatitis B virus (HBV) has been suggested as one of the mechanisms for HBV-associated hepatocellular carcinoma. However, such functions of HBx have been studied using transformed cells in culture and have not been examined in the normal adult hepatocytes, a natural host of HBV. Using an efficient hepatocyte-specific virus-based gene delivery system developed in our laboratory earlier, we studied the HBx action in vivo. We demonstrate that following virosome-mediated delivery of HBx DNA, a large population (>50%) of hepatocytes express the HBx protein in a dose-dependent manner, which induces a significant increase in the activity of extracellular signal-regulated kinases (ERKs) in the livers of HBx-transfected mice. Inhibition of HBx-induced ERK activation following intravenous administration of PD98059, a mitogen-activated protein kinase kinase kinase (MEK) inhibitor, confirmed the requirement for MEK in the activation of ERKs by HBx. Induction of ERK activity by HBx was sustained for up to 30 days. Interestingly, sustained activation of c-Jun N-terminal kinases (JNKs) for up to 30 days was also noted. Such constitutive ERK and JNK activation as a consequence of continued HBx expression also led to sustained stimulation of further downstream events, such as increased levels of c-Jun and c-Fos proteins along with the persistent induction of activator protein 1 binding activity. Taken together, our data suggest a critical role of these molecules in HBx-mediated cell transformation.
Cloning and Sequencing of Defective Particles Derived from the Autonomous Parvovirus Minute Virus of Mice for the Construction of Vectors with Minimal
cis
-Acting Sequences
Authors: Clément Nathalie , Avalosse Bernard , El Bakkouri Karim , Velu Thierry , Brandenburger Annick 
Published: July 2002

ABSTRACT

The production of wild-type-free stocks of recombinant parvovirus minute virus of mice [MVM(p)] is difficult due to the presence of homologous sequences in vector and helper genomes that cannot easily be eliminated from the overlapping coding sequences. We have therefore cloned and sequenced spontaneously occurring defective particles of MVM(p) with very small genomes to identify the minimal
cis
-acting sequences required for DNA amplification and virus production. One of them has lost all capsid-coding sequences but is still able to replicate in permissive cells when nonstructural proteins are provided in
trans
by a helper plasmid. Vectors derived from this particle produce stocks with no detectable wild-type MVM after cotransfection with new, matched, helper plasmids that present no homology downstream from the transgene.
Role of Vaccinia Virus A20R Protein in DNA Replication: Construction and Characterization of Temperature-Sensitive Mutants
Authors: Ishii Koji , Moss Bernard 
Published: July 2002

ABSTRACT
Previous analyses of randomly generated, temperature-sensitive vaccinia virus mutants led to the mapping of DNA synthesis negative complementation groups to the B1R, D4R, D5R, and E9L genes. Evidence from the yeast two-hybrid system that the D4R and D5R proteins can interact with the A20R protein suggested that A20R was also involved in DNA replication. We found that the A20R gene was transcribed early after infection, consistent with such a role. To investigate the function of the A20R protein, targeted mutations were made by substituting alanines for charged amino acids occurring in 11 different clusters. Four mutants were not isolated, suggesting that they were lethal, two mutants exhibited no temperature sensitivity, two mutants exhibited partial temperature sensitivity, and two mutants formed no plaques or infectious virus at 39°C. The two mutants with stringent phenotypes were further characterized. Temperature shift-up experiments indicated that the crucial period was between 6 and 12 h after infection, making it unlikely that the defect was in virus entry, early gene expression, or a late stage of virus assembly. Similar patterns of metabolically labeled viral early proteins were detected at permissive and nonpermissive temperatures, but one mutant showed an absence of late proteins under the latter conditions. Moreover, no viral DNA synthesis was detected when cells were infected with either stringent mutant at 39°C. The previous yeast two-hybrid analysis together with the present characterization of A20R temperature-sensitive mutants suggested that the A20R, D4R, and D5R proteins are components of a multiprotein DNA replication complex.
Evolution of Replication Efficiency following Infection with a Molecularly Cloned Feline Immunodeficiency Virus of Low Virulence
Authors: Hosie Margaret J. , Willett Brian J. , Klein Dieter , Dunsford Thomas H. , Cannon Celia , Shimojima Masayuki , Neil James C. , Jarrett Oswald 
Published: July 2002

ABSTRACT

The development of an effective vaccine against human immunodeficiency virus is considered to be the most practicable means of controlling the advancing global AIDS epidemic. Studies with the domestic cat have demonstrated that vaccinal immunity to infection can be induced against feline immunodeficiency virus (FIV); however, protection is largely restricted to laboratory strains of FIV and does not extend to primary strains of the virus. We compared the pathogenicity of two prototypic vaccine challenge strains of FIV derived from molecular clones; the laboratory strain PET
F14
and the primary strain GL8
414
. PET
F14
established a low viral load and had no effect on CD4
+
- or CD8
+
-lymphocyte subsets. In contrast, GL8
414
established a high viral load and induced a significant reduction in the ratio of CD4
+
to CD8
+
lymphocytes by 15 weeks postinfection, suggesting that PET
F14
may be a low-virulence-challenge virus. However, during long-term monitoring of the PET
F14
-infected cats, we observed the emergence of variant viruses in two of three cats. Concomitant with the appearance of the variant viruses, designated 627
W135
and 628
W135,
we observed an expansion of CD8
+
-lymphocyte subpopulations expressing reduced CD8 β-chain, a phenotype consistent with activation. The variant viruses both carried mutations that reduced the net charge of the V3 loop (K409Q and K409E), giving rise to a reduced ability of the Env proteins to both induce fusion and to establish productive infection in CXCR4-expressing cells. Further, following subsequent challenge of naïve cats with the mutant viruses, the viruses established higher viral loads and induced more marked alterations in CD8
+
-lymphocyte subpopulations than did the parent F14 strain of virus, suggesting that the E409K mutation in the PET
F14
strain contributes to the attenuation of the virus.
Mutant Tax Protein from Bovine Leukemia Virus with Enhanced Ability To Activate the Expression of c
-fos
Authors: Tajima Shigeru , Aida Yoko 
Published: July 2002

ABSTRACT

Bovine leukemia virus (BLV) is the etiologic agent of enzootic bovine leukosis. We previously identified several mutants of the BLV Tax protein with an ability to transactivate transcription via the BLV enhancer that is significantly greater than that of the wild-type Tax protein. Moreover, the mutant proteins also activated other viral enhancers, such as the enhancer of human T-cell leukemia virus type 1, which cannot be activated by wild-type BLV Tax. In this study, we demonstrated that the mutant proteins but not wild-type protein activate the upstream sequence of the human c
-fos
gene, which contains two major
cis
-acting elements, the CArG box and cyclic AMP-responsive element (CRE) motif. The mutant protein also strongly increased levels of endogenous c-
fos
mRNA in both human and bovine cell lines. On the other hand, the wild-type Tax protein has no activity to activate the expression of human c-
fos
, indicating that wild-type BLV Tax might discriminate between human and bovine c-
fos
promoter sequences. Deletion and point-mutational analysis of the
cis
-acting elements revealed that both the CArG box and the CRE motif were indispensable for the activation of c-
fos
by the mutant BLV Tax protein. Our results suggest that the mutant BLV Tax proteins might not only have the ability to enhance the production of virus particles but might also have increased ability to induce leukemia.
High Frequency of Virus-Specific B Lymphocytes in Germinal Centers of Simian-Human Immunodeficiency Virus-Infected Rhesus Monkeys
Authors: Margolin David H. , Helmuth Saunders Erika F. , Bronfin Benjamin , de Rosa Nicole , Axthelm Michael K. , Alvarez Xavier , Letvin Norman L. 
Published: July 2002

ABSTRACTThe etiology of the lymphadenopathy and follicular hyperplasia associated with human immunodeficiency virus type 1 (HIV-1) infection has remained unclear. To determine whether the B-lymphocyte expansions characteristic of this syndrome represent polyclonal and virus-specific processes, the antigen specificity of B cells in lymphoid tissues of monkeys infected with simian-human immunodeficiency virus (SHIV) chimeras was assessed using an inverse immunohistochemical assay with biotinylated HIV-1 envelope gp120 (Env) as an antigen probe. Env-binding B cells were found aggregated in lymph node and splenic germinal centers (GCs). Most Env-binding GCs also contained an unstained population of B cells, suggesting the GCs were formed by a polyclonal (oligoclonal) process. By day 42 following infection, Env-binding B cells were present in 19% of all lymph node GCs. Env-binding cells were present in 25% of GCs even during chronic infection. This extraordinarily high frequency of Env-specific B lymphocytes suggests that the expansion of virus-specific B cells may largely account for the follicular hyperplasia in AIDS virus-infected individuals.
In situ Mössbauer Study of the Passive Layer Formed on the Iron Anode in Alkaline Electrolyte
Authors: Bouzek Karel , Nejezchleba Martin 
Published: July 2002

In situ Mössbauer spectra of the iron electrode at anodic potential were measured in sodium hydroxide solution over a wide range of concentrations (0.1 - 14 mol l-1). It was found that the in situ Mössbauer spectra exhibit generally one sextet and one doublet corresponding to the oxide layer on the anode surface. Parameters of these spectra show only minor variations within the electrolyte concentration range of 0.1 - 7 M NaOH. A pronounced change in the spectra was observed in 14 M NaOH. The major processes taking place in the anode surface layer are based on the break-down of protective properties of the passive layer, incipient intense metal dissolution and subsequent oxidation. Important differences were also found between in situ and ex situ spectra measurements.
Phaeochromocytoma unearthed by fluoxetine
Authors: Kashyap A S 
Published: July 2002

Abstract
Non-specific noradrenaline reuptake inhibition by high dose selective serotonin reuptake inhibitors, along with catecholamine release from phaeochromocytoma, may lead to a hypertensive paroxysm. This may unmask a clinically silent phaeochromocytoma. Hypertensive paroxysm induced by paroxetine leading to detection of phaeochromocytoma has been reported. The first patient in whom fluoxetine unmasked a phaeochromocytoma is reported.
Modern management of oesophageal varices
Authors: Gow P J , Chapman R W 
Published: July 2002

Abstract
Haemorrhage from oesophageal varices is a life threatening emergency with a mortality rate in the order of 30%–50%. In the last three decades there have been many advances in the treatment and prevention of variceal bleeding. Over recent years the introduction of new pharmaceutical agents that reduce portal pressure, endoscopic variceal ligation, transjugular intrahepatic portosystemic shunt, and the availability of liver transplantation have further increased the therapeutic options available to the physician treating this disorder. This article reviews the literature regarding therapies available in the treatment of haemorrhage from oesophageal varices and provides guidelines to aid the physicians in clinical decision making.
Failure to develop diabetic ketoacidosis in a newly presenting type 1 diabetic patient
Authors: McNulty S J , Hardy K J 
Published: July 2002

Abstract
An 18 year old woman presented with a two week history of polyuria, polydypsia, and accelerated weight loss. On examination she was thin, dehydrated, hypotensive (blood pressure 88/58 mm Hg), and tachycardic (pulse 130 beats/min). Random blood glucose concentration was 20.2 mmol/l and she had hyponatraemia, hyperkalaemia, and mild uraemia (consistent with diabetic ketoacidosis); however, she was not ketoacidotic (box 1). She was diagnosed as having diabetes (subsequent testing confirmed a diagnosis of type 1 diabetes mellitus) and treated with intravenous insulin and intravenous fluid. On further questioning, she admitted to a 13 month history of easy tanning, weight loss, generalised weakness, reduced appetite, and several episodes of collapse with abdominal pain.
Closure of traumatic wounds without cleaning and suturing
Authors: Maharaj D , Sharma D , Ramdass M , Naraynsingh V 
Published: July 2002

Abstract

Background
In less than ideal situations wounds have to be closed without extensive cleaning using sterile adhesive strips (Steristrips). This prospective analyses the efficiency of this technique and compares it to the more conventional approach.

Methods
Altogether 147 lacerations were closed with sterile strips with no wound cleaning. Patients were subsequently followed up for a minimum of three months.

Results
The sepsis rate in compliant patients was 1.4% with a total complication rate of 2.7%.

Conclusion
This technique, while contradicting the “sacred tenets” of wound closure, is a cheap, quick, and effective alternative to routine closure of traumatic wounds in a casualty department.