bluuebunny/crossref_metadata_2025_split huggingface dataset:
Lymphotoxin-α-Deficient Mice Can Clear a Productive Infection with Murine Gammaherpesvirus 68 but Fail To Develop Splenomegaly or Lymphocytosis
Authors: Lee Bong Joo , Santee Sybil , Von Gesjen Sigrid , Ware Carl F. , Sarawar Sally R. 
Published: July 2002

ABSTRACTRespiratory challenge with murine gammaherpesvirus 68 (MHV-68) leads to an acute productive infection of the lung and a persistent latent infection in B lymphocytes, epithelia, and macrophages. The virus also induces splenomegaly and an increase in the number of activated CD8 T cells in the circulation. Lymphotoxin- α-deficient (LTα−/−) mice have no lymph nodes and have disrupted splenic architecture. Surprisingly, in spite of the severe defect in secondary lymphoid tissue, LTα−/−mice could clear a productive MHV-68 infection, although with delayed kinetics compared to wild-type mice, and could control latent infection. Cytotoxic T-cell activity was comparable in the lungs and spleens of LTα−/−and wild-type mice. However, splenic gamma interferon responses were substantially reduced in LTα−/−mice. Furthermore, LTα−/−mice failed to develop splenomegaly or lymphocytosis. Although germinal centers were absent, LTα−/−mice were able to class switch and showed significant virus-specific antibody titers. This work demonstrates that organized secondary lymphoid tissue is not an absolute requirement for the generation of immune responses to viral infections.
Modulation of Antigen-Specific Humoral Responses in Rhesus Macaques by Using Cytokine cDNAs as DNA Vaccine Adjuvants
Authors: Kim Jong J. , Yang Joo-Sung , VanCott Thomas C. , Lee Daniel J. , Manson Kelledy H. , Wyand Michael S. , Boyer Jean D. , Ugen Kenneth E. , Weiner David B. 
Published: July 2002

ABSTRACTAn important limitation of DNA immunization in nonhuman primates is the difficulty in generating high levels of antigen-specific antibody responses; strategies to enhance the level of immune responses to DNA immunization may be important in the further development of this vaccine strategy for humans. We approached this issue by testing the ability of molecular adjuvants to enhance the levels of immune responses generated by multicomponent DNA vaccines in rhesus macaques. Rhesus macaques were coimmunized intramuscularly with expression plasmids bearing genes encoding Th1 (interleukin 2 [IL-2] and gamma interferon)- or Th2 (IL-4)-type cytokines and DNA vaccine constructs encoding human immunodeficiency virus Env and Rev and simian immunodeficiency virus Gag and Pol proteins. We observed that the cytokine gene adjuvants (especially IL-2 and IL-4) significantly enhanced antigen-specific humoral immune responses in the rhesus macaque model. These results support the assumption that antigen-specific responses can be engineered to a higher and presumably more desirable level in rhesus macaques by genetic adjuvants.
Dominant-Negative Inhibition of Prion Formation Diminished by Deletion Mutagenesis of the Prion Protein
Authors: Zulianello Laurence , Kaneko Kiyotoshi , Scott Michael , Erpel Susanne , Han Dong , Cohen Fred E. , Prusiner Stanley B. 
Published: July 2002

ABSTRACTPolymorphic basic residues near the C terminus of the prion protein (PrP) in humans and sheep appear to protect against prion disease. In heterozygotes, inhibition of prion formation appears to be dominant negative and has been simulated in cultured cells persistently infected with scrapie prions. The results of nuclear magnetic resonance and mutagenesis studies indicate that specific substitutions at the C-terminal residues 167, 171, 214, and 218 of PrPCact as dominant-negative, inhibitors of PrPScformation (K. Kaneko et al., Proc. Natl. Acad. Sci. USA 94:10069–10074, 1997). Trafficking of substituted PrPCto caveaola-like domains or rafts by the glycolipid anchor was required for the dominant-negative phenotype; interestingly, amino acid replacements at multiple sites were less effective than single-residue substitutions. To elucidate which domains of PrPCare responsible for dominant-negative inhibition of PrPScformation, we analyzed whether N-terminally truncated PrP(Q218K) molecules exhibited dominant-negative effects in the conversion of full-length PrPCto PrPSc. We found that the C-terminal domain of PrP is not sufficient to impede the conversion of the full-length PrPCmolecule and that N-terminally truncated molecules (with residues 23 to 88 and 23 to 120 deleted) have reduced dominant-negative activity. Whether the N-terminal region of PrP acts by stabilizing the C-terminal domain of the molecule or by modulating the binding of PrPCto an auxiliary molecule that participates in PrPScformation remains to be established.
Functional Analysis of the Simian Immunodeficiency Virus Vpx Protein: Identification of Packaging Determinants and a Novel Nuclear Targeting Domain
Authors: Mahalingam Sundarasamy , Van Tine Brian , Santiago Mario L. , Gao Feng , Shaw George M. , Hahn Beatrice H. 
Published: July 2002

ABSTRACTThevpxgene products of human immunodeficiency virus type 2 (HIV-2) and of the closely related simian immunodeficiency viruses from sooty mangabeys (SIVsm) and macaques (SIVmac) comprise a 112-amino-acid virion-associated protein that is critical for efficient virus replication in nondividing cells such as macrophages. When expressed in the absence of other viral proteins, Vpx localizes to the nuclear membrane as well as to the nucleus; however, in the context of virus replication Vpx is packaged into virions via interaction with the p6 domain of the Gag precursor polyprotein (p55gag). To identify the domains essential for virion incorporation and nuclear localization, site-directed mutations were introduced into thevpxgene of SIVsmPBj1.9 and functionally analyzed. Our results show that (i) mutation of two highly conserved L74 and I75 residues impaired both virion incorporation and nuclear localization of Vpx; (ii) substitution of conserved H82, G86, C87, P103, and P106 residues impaired Vpx nuclear localization but not virion incorporation; (iii) mutations of conserved Y66, Y69, and Y71 residues impaired virion incorporation but not the translocation of Vpx to the nucleus; and (iv) a mutation at E30 (predicted to disrupt an N-terminal α-helix) had no effect on either virion incorporation or nuclear localization of Vpx. Importantly, mutations in Vpx which impaired nuclear localization also reduced virus replication in macaque macrophages, suggesting an important role of the carboxyl terminus of Vpx in nuclear translocation of the viral preintegration complex. Analyzing this domain in greater detail, we identified a 26-amino-acid (aa 60 to 85) fragment that was sufficient to mediate the transport of a heterologous protein (green fluorescent protein [GFP]) to the nucleus. Taken together, these results indicate that virion incorporation and nuclear localization are encoded by two partially overlapping domains in the C-terminus of Vpx (aa 60 to 112). The identification of a novel 26-amino-acid nuclear targeting domain provides a new tool to investigate the nuclear import of the HIV-2/SIV preintegration complex.
Detailed Analysis of the Requirements of Hepatitis A Virus Internal Ribosome Entry Segment for the Eukaryotic Initiation Factor Complex eIF4F
Authors: Borman Andrew M. , Michel Yanne M. , Kean Katherine M. 
Published: July 2002

ABSTRACT
The hepatitis A virus (HAV) internal ribosome entry segment (IRES) is unique among the picornavirus IRESs in that it is inactive in the presence of either the entero- and rhinovirus 2A or aphthovirus Lb proteinases. Since these proteinases both cleave eukaryotic initiation factor 4G (eIF4G) and HAV IRES activity could be rescued in vitro by addition of eIF4F to proteinase-treated extracts, it was concluded that the HAV IRES requires eIF4F containing intact eIF4G. Here, we show that the inability of the HAV IRES to function with cleaved eIF4G cannot be attributed to inefficient binding of the cleaved form of eIF4G by the HAV IRES. Indeed, the binding of both intact eIF4F and the C-terminal cleavage product of eIF4G to the HAV IRES was virtually indistinguishable from their binding to the encephalomyocarditis virus IRES, as assessed by UV cross-linking and filter retention assays. Rather, we show that HAV IRES activity requires, either directly or indirectly, components of the eIF4F complex which interact with the N-terminal fragment of eIF4G. Effectively, HAV IRES activity, but not that of the human rhinovirus IRES, was sensitive to the rotavirus nonstructural protein NSP3 [which displaces poly(A)-binding protein from the eIF4F complex], to recombinant eIF4E-binding protein (which prevents the association of the cap binding protein eIF4E with eIF4G), and to cap analogue.
Molecular Determinants of Virulence, Cell Tropism, and Pathogenic Phenotype of Infectious Bursal Disease Virus
Authors: Brandt Meggin , Yao Kun , Liu Meihong , Heckert Robert A. , Vakharia Vikram N. 
Published: July 2002

ABSTRACT

Infectious bursal disease viruses (IBDVs), belonging to the family
Birnaviridae
, exhibit a wide range of immunosuppressive potential, pathogenicity, and virulence for chickens. The genomic segment A encodes all the structural (VP2, VP4, and VP3) and nonstructural proteins, whereas segment B encodes the viral RNA-dependent RNA polymerase (VP1). To identify the molecular determinants for the virulence, pathogenic phenotype, and cell tropism of IBDV, we prepared full-length cDNA clones of a virulent strain, Irwin Moulthrop (IM), and constructed several chimeric cDNA clones of segments A and B between the attenuated vaccine strain (D78) and the virulent IM or GLS variant strain. Using the cRNA-based reverse-genetics system developed for IBDV, we generated five chimeric viruses after transfection by electroporation procedures in Vero or chicken embryo fibroblast (CEF) cells, one of which was recovered after propagation in embryonated eggs. To evaluate the characteristics of the recovered viruses in vivo, we inoculated 3-week-old chickens with D78, IM, GLS, or chimeric viruses and analyzed their bursae for pathological lesions 3 days postinfection. Viruses in which VP4, VP4-VP3, and VP1 coding sequences of the virulent strain IM were substituted for the corresponding region in the vaccine strain failed to induce hemorrhagic lesions in the bursa. In contrast, viruses in which the VP2 coding region of the vaccine strain was replaced with the variant GLS or virulent IM strain caused rapid bursal atrophy or hemorrhagic lesions in the bursa, as seen with the variant or classical virulent strain, respectively. These results show that the virulence and pathogenic-phenotype markers of IBDV reside in VP2. Moreover, one of the chimeric viruses containing VP2 sequences of the virulent strain could not be recovered in Vero or CEF cells but was recovered in embryonated eggs, suggesting that VP2 contains the determinants for cell tropism. Similarly, one of the chimeric viruses containing the VP1 segment of the virulent strain could not be recovered in Vero cells but was recovered in CEF cells, suggesting that VP1 contains the determinants for cell-specific replication in Vero cells. By comparing the deduced amino acid sequences of the D78 and IM strains and their reactivities with monoclonal antibody 21, which binds specifically to virulent IBDV, the putative amino acids involved in virulence and cell tropism were identified. Our results indicate that residues Gln at position 253 (Gln253), Asp279, and Ala284 of VP2 are involved in the virulence, cell tropism, and pathogenic phenotype of virulent IBDV.
In Vitro Selection and Characterization of Influenza A (A/N9) Virus Variants Resistant to a Novel Neuraminidase Inhibitor, A-315675
Authors: Molla Akhteruzzaman , Kati Warren , Carrick Robert , Steffy Kevin , Shi Yan , Montgomery Debra , Gusick Nanette , Stoll Vincent S. , Stewart Kent D. , Ng Teresa I. , Maring Clarence , Kempf Dale J. , Kohlbrenner William 
Published: July 2002

ABSTRACT
With the recent introduction of neuraminidase (NA) inhibitors into clinical practice for the treatment of influenza virus infections, considerable attention has been focused on the potential for resistance development and cross-resistance between different agents from this class. A-315675 is a novel influenza virus NA inhibitor that has potent enzyme activity and is highly active in cell culture against a variety of strains of influenza A and B viruses. To further assess the therapeutic potential of this compound, in vitro resistance studies have been conducted and a comparative assessment has been made relative to oseltamivir carboxylate. The development of viral resistance to A-315675 was studied by in vitro serial passage of influenza A/N9 virus strains grown in MDCK cells in the presence of increasing concentrations of A-315675. Parallel passaging experiments were conducted with oseltamivir carboxylate, the active form of a currently marketed oral agent for the treatment of influenza virus infections. Passage experiments with A-315675 identified a variant at passage 8 that was 60-fold less susceptible to the compound. Sequencing of the viral population identified an E119D mutation in the NA gene, but no mutations were observed in the hemagglutinin (HA) gene. However, by passage 10 (2.56 μM A-315675), two mutations (R233K, S339P) in the HA gene appeared in addition to the E119D mutation in the NA gene, resulting in a 310-fold-lower susceptibility to A-315675. Further passaging at higher drug concentrations had no effect on the generation of further NA or HA mutations (20.5 μM A-315675). This P15 virus displayed 355-fold-lower susceptibility to A-315675 and >175-fold-lower susceptibility to zanamivir than did wild-type virus, but it retained a high degree of susceptibility to oseltamivir carboxylate. By comparison, virus variants recovered from passaging against oseltamivir carboxylate (passage 14) harbored an E119V mutation and displayed a 6,000-fold-lower susceptibility to oseltamivir carboxylate and a 175-fold-lower susceptibility to zanamivir than did wild-type virus. Interestingly, this mutant still retained susceptibility to A-315675 (42-fold loss). This suggests that cross-resistance between A-315675- and oseltamivir carboxylate-selected variants in vitro is minimal.
Kunjin Virus Replicon Vaccine Vectors Induce Protective CD8+T-Cell Immunity
Authors: Anraku Itaru , Harvey Tracey J. , Linedale Richard , Gardner Joy , Harrich David , Suhrbier Andreas , Khromykh Alexander A. 
Published: July 2002

ABSTRACTThe ability of self-replicating RNA (replicon) vaccine vectors derived from the Australian flavivirus Kunjin (KUN) to induce protective αβ CD8+T-cell responses was examined. KUN replicons encoding a model immunogen were delivered by three different vaccine modalities: (i) as naked RNA transcribed in vitro, (ii) as plasmid DNA constructed to allow in vivo transcription of replicon RNA by cellular RNA polymerase II (DNA based), and (iii) as replicon RNA encapsidated into virus-like particles. A single immunization with any of these KUN replicon vaccines induced CD8+T-cell responses at levels comparable to those induced by recombinant vaccinia virus encoding the same immunogen. Immunization with only 0.1 μg of DNA-based KUN replicons elicited CD8+T-cell responses similar to those seen after immunization with 100 μg of a conventional DNA vaccine. Naked RNA immunization with KUN replicons also protected mice against challenges with recombinant vaccinia virus and B16 tumor cells. These results demonstrate the value of KUN replicon vectors for inducing protective antiviral and anticancer CD8+T-cell responses.
Tat-Vaccinated Macaques Do Not Control Simian Immunodeficiency Virus SIVmac239 Replication
Authors: Allen Todd M. , Mortara Lorenzo , Mothé Bianca R. , Liebl Max , Jing Peicheng , Calore Briana , Piekarczyk Marian , Ruddersdorf Richard , O'Connor David H. , Wang X. , Wang Chenxi , Allison David B. , Altman John D. , Sette Alessandro , Desrosiers Ronald C. , Sutter Gerd , Watkins David I. 
Published: July 2002

ABSTRACTThe regulatory proteins of human immunodeficiency virus may represent important vaccine targets. Here we assessed the role of Tat-specific cytotoxic T lymphocytes (CTL) in controlling pathogenic simian immunodeficiency virus SIVmac239 replication after using a DNA-prime, vaccinia virus Ankara-boost vaccine regimen. Despite the induction of Tat-specific CTL, there was no significant reduction in either peak or viral set point compared to that of controls.
The Role of MoO3 and Fe2O3 in the Thermal Decomposition of Ammonium Perchlorate
Authors: Halawy Samih A. , Mohamed Mohamed A. 
Published: July 2002

The effect of addition of MoO3 and Fe2O3 as well as mixtures of the two oxides (calcined in air at 500 °C) on the thermal decomposition of ammonium perchlorate (AP) was studied using thermogravimetry (TGA) and derivative thermogravimetric analysis (DTG). The catalysts calcined at 500 °C were characterized using TPR, XPS and XRD techniques. The surface area of the catalysts was determined by means of the conventional BET method. The results are discussed in terms of the recently published mechanism in which nitryl perchlorate is supposed as an intermediate in the thermal decomposition of pure AP. The correlation between the surface area and activity of the catalysts in the thermal decomposition of AP has been done. The activation energy (∆E) for non-catalyzed and catalyzed high-temperature thermal decomposition of AP were calculated from the TGA results using the Coats-Redfern equation.
Neurodevelopmental outcome in meningococcal disease: a case–control study
Authors: Fellick J M , Sills J A , Marzouk O , Hart C A , Cooke R W I , Thomson A P J 
Published: July 2002

AIMSTo determine long term neurodevelopmental outcome following the spectrum of meningococcal infection.METHODSBetween 1988 and 1990, 152 cases of meningococcal disease were recruited; 139 survived. Between 1998 and 1999, 115 survivors (83%) were evaluated, together with 115 sex and age matched controls. Standard measures of neurological function, coordination, cognition, behaviour, and hearing were used to assess neurodevelopmental status.RESULTSOne case has spastic quadriplegia. Gross neurological examination was normal in all other cases and all controls. Five cases and no controls have significant hearing loss. Cases performed at a lower level than controls on measures of coordination, cognition, and behaviour. Four cases and no controls had major impairments. The adjusted odds ratios for moderate and minor impairments were 3.6 (95% CI 1.3 to 10.3) and 1.6 (95% CI 0.8 to 3.4) respectively.CONCLUSIONThe majority of survivors from this cohort do not have gross neurological deficits. However, when objective measures of motor function, cognitive ability, and behaviour were applied significant detriments were found in meningococcal survivors.
Delivery of surgical care in a district general hospital without high dependency unit facilities
Authors: Coggins R P 
Published: July 2002

Abstract

Background
Many hospitals lack the facilities for high dependency care, and patients requiring this level of care are nursed on the surgical ward. The aim of this study was to assess the extent of this problem in a district general hospital, looking at the impact of providing high dependency unit (HDU) care at ward level.

Methods
A 28 bed surgical ward was studied for 39 consecutive days. Patients were assessed as being either appropriately placed (routine) or inappropriately placed (HDU). Nursing interventions and observations over each 24 hour period were recorded for the most dependent patient in each group.

Results
Data were collected for a total of 1092 bed days. Median bed occupancy was 22 patients/day (78%). Inappropriately placed HDU patients accounted for 55 bed days (5%, mean 1.4 patients/day). These patients required more nursing intervention than routine patients.
HDU patients received more observations during a 24 hour period than routine patients (mean 11.3 and 4.2 respectively, p&lt;0.005). The number of observations recorded for a routine patient in a 24 hour period fell when a HDU patient was nursed concurrently on the ward (mean 5.1/24 hours, falling to 3.8 /24 hours in the presence of an HDU patient, p&lt;0.02 ).

Conclusions
HDU patients require more intensive nursing care than routine surgical patients, and the nursing of HDU patients on the ward adversely affects the quantity of care available for less dependent patients. High dependency care should therefore be provided in dedicated units.
HDU is an essential facility for all surgical patients, including those who require intensive nursing, and the routine surgical patient whose nursing is compromised by the failure to provide comprehensive postoperative care.
Carotid sinus syndrome masquerading as treatment resistant epilepsy
Authors: Parry Steve W , Kenny Rose Anne 
Published: July 2002

Abstract
A 65 year old woman had a 12 year history of frequent, recurrent seizure-like episodes labelled as treatment resistant epilepsy after neurological evaluation and follow up and treatment with multiple antiepileptic medications. Carotid sinus massage provoked 5.6 seconds asystole with symptom reproduction, and she has remained symptom-free after permanent pacemaker implantation for her carotid sinus syndrome and withdrawal of antiepileptic medications.
Parasites in fine needle breast aspirates—assessment of host tissue response
Authors: Sahai K , Kapila K , Verma K 
Published: July 2002

Abstract
Parasites in the human breast are uncommon but not rare. Cysticercus and filariasis in fine needle breast aspirates have been documented and their cytomorphology is well characterised. However, the host tissue response to these parasites and the factors responsible for their initiation are not clear. Over a 21 year period, 28 cases of breast parasites (16 cases of cysticercus and 12 of filariasis), diagnosed by fine needle aspiration cytology, were reviewed to assess the host tissue response.
CHARACTERISATION OF CONDUCTING POLYMERS USING ION BEAM ANALYSIS
Authors: MORETTO G. L. , MARKWITZ A. , HALL S. B. , BURRELL A. K. , OFFICER D. L. , CAMPBELL W. M , COLLIS G. E. 
Published: July 2002

Complex bis terthiophene porphyrin conducting polymers were used to investigate the uptake of zinc into the freebase porphyrin unit after polymerisation by acquiring depth profiles using Rutherford Backscatting Spectrometry (RBS) analysis. Issues such as the influence of the support material and extent of polymer oxidation on the dispersion of the counter ions through the polymer films are of importance. Gaining knowledge of the dispersion of counter ions provides new insights into the redox mechanisms for conductive polymers. The results were compared to those obtained from a sample where zinc was coordinated to the porphyrin prior to the polymerisation process. Unexpectedly high concentration of both nitrogen and oxygen were found which could be due to evidence of the trapped cations from the electrolyte ( (Bu) 4 N +), and trapped water molecules, within the polymer films. The chlorine concentrations help to understand the dispersion of the perchlorate counter ion throughout the polymer films, and the combination of both RBS and Proton Induced X-ray Emission (PIXE) show that trace element impurities can be detected using ion beam analysis which other analytical techniques are unable to do.