bluuebunny/crossref_metadata_2025_split huggingface dataset:
Heterologous Protection Induced by the Inner Capsid Proteins of Rotavirus Requires Transcytosis of Mucosal Immunoglobulins
Authors: Schwartz-Cornil Isabelle , Benureau Yann , Greenberg Harry , Hendrickson Barbara A. , Cohen Jean 
Published: July 2002

ABSTRACTProtective immunization against rotavirus (RV) can be achieved with heterologous RV, i.e., virus isolated from another species, and with heterologous inner core VP2 and VP6 proteins assembled as virus-like particles (VLP). Although the antigenically conserved VP6 protein does not induce in vitro-neutralizing antibodies, it may, however, elicit immunoglobulins (Ig) involved in heterologous protection, as some IgA against VP6 prevent RV infection in a backpack mouse model. The protective role of Ig directed to the RV inner core proteins VP2 and VP6 was investigated in J-chain-deficient mice (J chain−/−), which have a defect in the polymeric Ig receptor (pIgR)-mediated transcytosis of IgA and IgM. J chain−/−mice and wild-type (WT) mice were intranasally vaccinated with bovine RV-derived VLP2/6 and then challenged with highly infectious murine ECw RV. Whereas WT mice were totally protected, immunized J chain−/−mice shed RV for several days. In addition, naïve J chain−/−mice exhibited a 2-day delay in clearing RV compared with WT mice. The immunized J chain−/−mice displayed unaltered VLP2/6-specific B-cell numbers in spleen and in mesenteric nodes and similar levels of serum anti-VLP2/6 Ig, confirming that the adaptive B-cell response is preserved in J chain−/−mice. These results indicate that J-chain-mediated transcytosis of Ig participates in the clearance of RV and that epithelial pIgR-mediated transport of Ig is involved in the heterologous protection induced by VLP2/6.
Effects of Prostratin on T-Cell Activation and Human Immunodeficiency Virus Latency
Authors: Korin Yael D. , Brooks David G. , Brown Stephen , Korotzer Andrew , Zack Jerome A. 
Published: July 2002

ABSTRACT
Human immunodeficiency virus (HIV) replication is linked to cellular gene transcription and requires target cell activation. The latent reservoir of HIV-1 in quiescent T cells is thought to be a major obstacle to clearance of infection by highly active antiretroviral therapy (HAART). Thus, identification of agents that can induce expression of latent virus may, in the presence of HAART, allow elimination of the infected cells by the immune response. We previously used the SCID-hu (Thy/Liv) mouse model to establish that activation-inducible HIV can be generated at high frequency during thymopoiesis. Latently infected mature thymocytes can be exported into the periphery, providing an efficient primary cell model to determine cellular activation signals that induce renewed expression of latent virus. Here we characterized the effects of prostratin, a non-tumor-promoting phorbol ester, on primary human peripheral blood lymphocytes (PBLs) and assessed its ability to reactivate latent HIV infection from thymocytes and PBLs in the SCID-hu (Thy/Liv) model. Prostratin stimulation alone did not induce proliferation of quiescent PBLs; however, it could provide a secondary signal in the context of T-cell receptor stimulation or a primary activation signal in the presence of CD28 stimulation to induce T-cell proliferation. While prostratin alone was not sufficient to allow de novo HIV infection, it efficiently reactivated HIV expression from latently infected cells generated in the SCID-hu mouse. Our data indicate that prostratin alone is able to specifically reactivate latent virus in the absence of cellular proliferation, making it an attractive candidate for further study as an adjunctive therapy for the elimination of the latent HIV reservoir.
Rebound of Hepatitis B Virus Replication in HepG2 Cells after Cessation of Antiviral Treatment
Authors: Abdelhamed Ayman M. , Kelley Colleen M. , Miller Thomas G. , Furman Phillip A. , Isom Harriet C. 
Published: July 2002

ABSTRACT
Treatment of patients with lamivudine (3TC) results in loss of detectable levels of hepatitis B virus (HBV) DNA from serum; however, the relapse rate, with regard to both reappearance of virus in the bloodstream and hepatic inflammation, is high when therapy is terminated. Although the rebound observed in patients has also been seen in animal hepadnavirus models, rebound has not been analyzed in an in vitro cell culture system. In this study, we used the HBV recombinant baculovirus/HepG2 system to measure the time course of antiviral agent-mediated loss of HBV replication as well as the time course and magnitude of HBV production after release from antiviral treatment. Because of the sensitivity of the system, it was possible to measure secreted virions, intracellular replicative intermediates, and nuclear non-protein-bound HBV DNA and separately analyze individual species of DNA, such as single-stranded HBV DNA compared to the double-stranded form and relaxed circular compared to covalently closed circular HBV DNA. We first determined that HBV replication in the HBV recombinant baculovirus/HepG2 system could proceed for at least 35 days, with a 30-day plateau level of replication, making it possible to study antiviral agent-mediated loss of HBV followed by rebound after cessation of drug treatment. All HBV DNA species decreased in a time-dependent fashion following antiviral treatment, but the magnitude of decline differed for each HBV DNA species, with the covalently closed circular form of HBV DNA being the most resistant to drug therapy. When drug treatment ceased, HBV DNA species reappeared with a pattern that recapitulated the initiation of replication, but with a different time course.
The Block in Assembly of Modified Vaccinia Virus Ankara in HeLa Cells Reveals New Insights into Vaccinia Virus Morphogenesis
Authors: Sancho M. Carmen , Schleich Sibylle , Griffiths Gareth , Krijnse-Locker Jacomine 
Published: July 2002

ABSTRACT
It has previously been shown that upon infection of HeLa cells with modified vaccinia virus Ankara (MVA), assembly is blocked at a late stage of infection and immature virions (IVs) accumulate (G. Sutter and B. Moss, Proc. Natl. Acad. Sci. USA 89:10847-10851, 1992). In the present study the morphogenesis of MVA in HeLa cells was studied in more detail and compared to that under two conditions that permit the production of infectious particles: infection of HeLa cells with the WR strain of vaccinia virus (VV) and infection of BHK cells with MVA. Using several quantitative and qualitative assays, we show that early in infection, MVA in HeLa cells behaves in a manner identical to that under the permissive conditions. By immunofluorescence microscopy (IF) at late times of infection, the labelings for an abundant membrane protein of the intracellular mature virus, p16/A14L, and the viral DNA colocalize under permissive conditions, whereas in HeLa cells infected with MVA these two structures do not colocalize to the same extent. In both permissive and nonpermissive infection, p16-labeled IVs first appear at 5 h postinfection. In HeLa cells infected with MVA, IVs accumulated predominantly outside the DNA regions, whereas under permissive conditions they were associated with the viral DNA. At 4 h 30 min, the earliest time at which p16 is detected, the p16 labeling was found predominantly in a small number of distinct puncta by IF, which were distinct from the sites of DNA in both permissive and nonpermissive infection. By electron microscopy, no crescents or IVs were found at this time, and the p16-labeled structures were found to consist of membrane-rich vesicles that were in continuity with the cellular endoplasmic reticulum. Over the next 30 min of infection, a large number of p16-labeled crescents and IVs appeared abruptly under both permissive and nonpermissive conditions. Under permissive conditions, these IVs were in close association with the sites of DNA, and a significant amount of these IVs engulfed the viral DNA. In contrast, under nonpermissive conditions, the IVs and DNA were mostly in separate locations and relatively few IVs acquired DNA. Our data show that in HeLa cells MVA forms normal DNA replication sites and normal viral precursor membranes but the transport between these two structures is inhibited.
Molecular Basis of the Attenuation Exhibited by Molecularly Cloned Highly Passaged Chicken Anemia Virus Isolates
Authors: Todd Daniel , Scott Alistair N. J. , Ball Neris W. , Borghmans Borghert J. , Adair Brian M. 
Published: July 2002

ABSTRACT
Chimeric virus experiments indicated that the pathogenicity and monoclonal antibody reactivity differences between two molecularly cloned, highly passaged chicken anemia virus isolates could be attributed to the VP1 amino acid change at residue 89. The introduction of this change into a pathogenic cloned low-passage isolate was not sufficient to cause attenuation.
Inserting a Nuclear Targeting Signal into a Replication-Competent Moloney Murine Leukemia Virus Affects Viral Export and Is Not Sufficient for Cell Cycle-Independent Infection
Authors: Seamon Jennifer A. , Jones Kathryn S. , Miller Christina , Roth Monica J. 
Published: July 2002

ABSTRACT

The effects of inserting reported nuclear localization signals (NLSs) into the Moloney murine leukemia virus (Mo-MuLV) integrase (IN) protein, within a replication-competent viral construct, were studied. In contrast to the virus harboring IN fused to the simian virus 40 (SV40) large T antigen NLS (SV40 NLS) (J. A. Seamon, M. Adams, S. Sengupta, and M. J. Roth, Virology
274:
412-419, 2000), a codon-modified SV40 NLS was stably expressed during viral propagation. Incorporation of the codon-modified SV40 NLS into IN, however, altered the packaging of the Gag-Pol precursor in the virus; viral particles contained decreased levels of reverse transcriptase (RT) and IN. In addition, the virus showed delayed kinetics of viral DNA synthesis upon infection. A panel of infectious MuLVs containing alternative IN-NLS fusions was generated and assayed for cell cycle-independent infection. Viral infection with the NLS-tagged proteins, however, remained dependent on passage of the cells through mitosis. This finding has direct implications for engineering murine-based retroviral vectors for gene therapy.
Analysis of Bovine Leukemia Virus Gag Membrane Targeting and Late Domain Function
Authors: Wang Huating , Norris Kendra M. , Mansky Louis M. 
Published: July 2002

ABSTRACT

Assembly of retrovirus-like particles only requires the expression of the Gag polyprotein precursor. We have exploited this in the development of a model system for studying the virus particle assembly pathway for bovine leukemia virus (BLV). BLV is closely related to the human T-cell leukemia viruses (HTLVs), and all are members of the
Deltaretrovirus
genus of the
Retroviridae
family. Overexpression of a BLV Gag polyprotein containing a carboxy-terminal influenza virus hemagglutinin (HA) epitope tag in mammalian cells led to the robust production of virus-like particles (VLPs). Site-directed mutations were introduced into HA-tagged Gag to test the usefulness of this model system for studying certain aspects of the virus assembly pathway. First, mutations that disrupted the amino-terminal glycine residue that is important for Gag myristylation led to a drastic reduction in VLP production. Predictably, the nature of the VLP production defect was correlated to Gag membrane localization. Second, mutation of the PPPY motif (located in the MA domain) greatly reduced VLP production in the absence of the viral protease. This reduction in VLP production was more severe in the presence of an active viral protease. Examination of particles by electron microscopy revealed an abundance of particles that began to pinch off from the plasma membrane but were not completely released from the cell surface, indicating that the PPPY motif functions as a late domain (L domain).
A clinical neurological, neurophysiological, and neuropsychological study of sheep farmers and dippers exposed to organophosphate pesticides
Authors: Jamal G A , Hansen S , Pilkington A , Buchanan D , Gillham R A , Abdel-Azis M , Julu P O O , Al-Rawas S F , Hurley F , Ballantyne J P 
Published: July 2002

Objectives:To classify clinical diseases of the subjects with abnormal indices of peripheral neuropathy identified in field studies of sheep farmers and dippers exposed to organophosphate pesticides. To explore what neuropsychological profiles, if any, may be associated with neurophysiological damage in these subjects.Methods:A case-control study (79 subjects) nested within the cross sectional study (685 subjects) of sheep farmers from the field study. Three groups with no, possible, and probable or definite neuropathy according to field studies were recruited. Investigations comprised symptoms of neuropathy, neurologial signs, motor and sensory nerve conduction, electromyography, quantitative sensory testing, and neuropsychological tests.Results:The incidence of clinical neuropathy increased from 7% in the no neuropathy group to 52% in the probable or definite neuropathy group based on nerve conduction measurements or presence of neurological signs. Sensory abnormalities were found more often than motor deficits. Small diameter nerve fibres were also affected more than large fibres.Conclusions:The neuropathy is predominantly sensory and is characteristic of distal, chronic neuropathy with no acute features. Small fibre populations are affected more than large fibre populations. Increasing severity of neuropathy was associated with anxiety and depression as measured in the neuropsychological tests.
Methicillin resistantStaphylococcus aureus(MRSA) in the intensive care unit
Authors: Haddadin A S , Fappiano S A , Lipsett P A 
Published: July 2002

AbstractMethicillin resistant Staphylococcus aureus (MRSA) is a major nosocomial pathogen that causes severe morbidity and mortality worldwide. MRSA strains are endemic in many American and European hospitals and account for 29%–35% of all clinical isolates. Recent studies have documented the increased costs associated with MRSA infection, as well as the importance of colonisation pressure. Surveillance strategies have been proposed especially in high risk areas such as the intensive care unit. Pneumonia and bacteraemia account for the majority of MRSA serious clinical infections, but intra-abdominal infections, osteomyelitis, toxic shock syndrome, food poisoning, and deep tissue infections are also important clinical diseases. The traditional antibiotic therapy for MRSA is a glycopeptide, vancomycin. New antibiotics have been recently released that add to the armamentarium for therapy against MRSA and include linezolid, and quinupristin/dalfopristin, but cost, side effects, and resistance may limit their long term usefulness.
Foreign body aspiration: clinical utility of flexible bronchoscopy
Authors: Dikensoy O , Usalan C , Filiz A 
Published: July 2002

AbstractForeign body aspiration is a worldwide health problem which often results in life threatening complications. More than two thirds of foreign body aspirations occur among children younger than 3 years. Organic materials such as nuts, seeds, and bones are most commonly aspirated. There is a wide range of clinical presentation, and often there is not a reliable witness to supply the clinical history, especially in children. Maintaining a high index of suspicion is therefore necessary for the diagnosis. None of the imaging methods employed in such cases are diagnostic, and bronchoscopy is frequently necessary for the diagnosis as well as the treatment. In adults, removal of the foreign body can be attempted during diagnostic examination with a fibreoptic bronchoscope under local anaesthesia, which may help to avoid any further invasive procedures with more complications. When diagnosis is delayed, complications of a retained foreign body such as unresolving pneumonia, lung abscess, recurrent haemoptysis, and bronchiectasis may necessitate a surgical resection. However, some of the late complications may resolve completely after the retrieval of the foreign body, therefore, a preoperative flexible bronchoscopy should always be considered in suitable cases.
Fatigue in cholestatic liver disease—a perplexing symptom
Authors: Kumar D , Tandon R K 
Published: July 2002

Abstract
Fatigue is an important symptom and a quality of life determinant in patients with cholestatic liver disease. The pathogenesis of fatigue is obscure, although alterations in central neurotransmission and peripheral muscle dysfunction have been incriminated. No effective treatment is available at present. The available literature on fatigue in cholestatic liver disease is reviewed.
Gamma-ray transmission technique for quality control of coal seams
Authors: Sekhar N R , Reddy SV SR , Rao A SN 
Published: July 2002

The useful heat value (UHV) that is the figure of merit for coal depends on various parameters such as fixed carbon, volatiles, ash, and moisture. The percentage of these materials present in a given sample of coal can be estimated by gamma-ray transmission studies. Using gamma rays of energies 30.85 and 81.0 keV, coal samples were studied and the relationships between attenuation coefficients and known UHV and ash contents were obtained. These relationships can be used to measure UHV/ash values for other samples using this simple, fast, and reliable nondestructive method. PACS No.: 32.80
Studies for the Odin sub-millimetre radiometer: III. Performance simulations
Authors: Merino F , Murtagh D P , Ridal M , Eriksson P , Baron P , Ricaud P , Noë J de la 
Published: July 2002

Odin is a small, low-cost satellite with a combined astronomical and aeronomical mission. The mission is divided on an equal basis between astronomy and aeronomy. The aeronomy objectives can be divided into four main subjects: stratospheric ozone chemistry, mesospheric ozone chemistry, the summer mesopause region, and the coupling between atmospheric regions. The primary instrument on Odin is the millimetre and sub-millimetre radiometer (SMR), which is used both for astronomy and aeronomy. It is the first satellite to use sub-millimetre frequencies for limb-sounding mode. Odin is also equipped with an optical spectrometer (OSIRIS). This paper is the third of a three-part series and describes the choices of observing modes and the expected performance of the SMR instrument for the aeronomy mission. The relevant frequencies are identified and the exact selection of lines is made. This is followed by a detailed simulation study to determine the achievable altitude coverage together with the corresponding vertical resolution for each retrievable species. An indication of the expected uncertainties is also given, showing, for example, a high-sensitivity to mesospheric water vapour and stratospheric chlorine monoxide. However, a complete analysis of observation uncertainties must await launch and the completion of the validation programme. PACS Nos.: 42.68A, 07.07D, 07.57K
THE AGILE MISSION AND GAMMA-RAY ASTROPHYSICS
Authors: TAVANI MARCO 
Published: July 2002

Gamma-ray astrophysics in the energy range between 30 MeV and 30 GeV is in desperate need of arcminute angular resolution and source monitoring capability. The AGILE Mission planned to be operational in 2004-2006 will be the only space mission entirely dedicated to gamma-ray astrophysics above 30 MeV. The main characteristics of AGILE are the simultaneous X-ray and gamma-ray imaging capability (reaching arcminute resolution) and excellent gamma-ray timing (10-100 microseconds). AGILE scientific program will emphasize a quick response to gamma-ray transients and multiwavelength studies of gamma-ray sources.
Human Secretory Phospholipase A2Mediates Decreased Plasma Levels of HDL Cholesterol and ApoA-I in Response to Inflammation in Human ApoA-I Transgenic Mice
Authors: Tietge Uwe J.F. , Maugeais Cyrille , Lund-Katz Sissel , Grass David , deBeer Frederick C. , Rader Daniel J. 
Published: July 2002

Objective—Plasma levels of high density lipoprotein (HDL) cholesterol and apolipoprotein (apo)A-I are decreased in inflammatory states. Secretory phospholipase A2(sPLA2), an acute-phase protein, may play a key role in the pathophysiology of this phenomenon.Methods and Results—To investigate the effects of sPLA2on human-like HDL particles in vivo, we generated transgenic mice overexpressing human apoA-I and human sPLA2(apoA-I/sPLA2mice). Compared with apoA-I mice, apoA-I/sPLA2mice had significantly lower plasma levels of phospholipids, HDL cholesterol, and apoA-I (eachP<0.01). HDL from apoA-I/sPLA2mice was significantly depleted in phospholipids and cholesteryl esters (eachP<0.001) but was enriched in protein and triglycerides (eachP<0.001). As assessed by gel filtration and nondenaturing gel electrophoresis, sPLA2overexpression in apoA-I mice resulted in a dramatic shift of the HDL particle size toward smaller particles. Furthermore, virtually all plasma sPLA2in apoA-I/sPLA2mice was found in association with the HDL fraction. The acute-phase response was induced in apoA-I/sPLA2double-transgenic and apoA-I single-transgenic mice by intraperitoneal lipopolysaccharide (LPS) injection. Plasma sPLA2was significantly increased after LPS injection in apoA-I/sPLA2mice. Twelve hours after LPS administration, plasma total cholesterol, HDL cholesterol, apoA-I, and phospholipids were unchanged in apoA-I transgenic control mice but had decreased significantly in the apoA-I/sPLA2mice (−57%, −62%, and −54%, −61%, respectively; eachP<0.001). Both groups of mice had increased plasma levels of serum amyloid A (SAA) in response to LPS. To test the hypothesis that SAA may be an in vivo activator of sPLA2, we specifically overexpressed SAA in apoA-I/sPLA2mice by means of liver-directed gene transfer. Despite high plasma levels of SAA, plasma lipid and lipoprotein profiles were not different than those in control mice.Conclusions—These results in a mouse model of human-like HDL indicate that sPLA2expression significantly influences HDL particle size and composition and demonstrate that an induction of sPLA2is required for the decrease in plasma HDL cholesterol in response to inflammatory stimuli in mice and that this effect is independent of SAA.
The Quantitative Nature of a Visual Task Differentiates between Ventral and Dorsal Stream
Authors: Fias Wim , Dupont Patrick , Reynvoet Bert , Orban Guy A. 
Published: July 2002

Abstract
The aim of the present positron emission tomography (PET) study was to investigate how visual processing in dorsal and ventral streams depends on the quantitative nature of the task. In the same—different task, participants identified the presence of an orientation difference between two gratings, presented centrally in succession. In the quantification task, participants estimated the magnitude of the difference and compared it to a fixed standard. Detection of dimming of the fixation point was used as a control task. Visual input, motor responses, and performance were equated across tasks. Subtracting same— different from quantification yielded significant activation in the left superior parietal lobule and left ventral premotor cortex, consistent with results obtained in number-processing tasks. The reverse subtraction yielded activation in the right inferior temporal gyrus, in agreement with earlier results. These results demonstrate that a single attribute can be processed either in the ventral or dorsal stream, depending on the cognitive operations required by the tasks.