bluuebunny/crossref_metadata_2025_split huggingface dataset:
Truncation of Herpes Simplex Virus Type 2 Glycoprotein B Increases Its Cell Surface Expression and Activity in Cell-Cell Fusion, but These Properties Are Unrelated
Authors: Fan Zhenghong , Grantham Michael L. , Smith M. Shane , Anderson Eric S. , Cardelli James A. , Muggeridge Martin I. 
Published: October 2002

ABSTRACTFormation of small polykaryons by cell-cell fusion is characteristic of herpes simplex virus (HSV) lesions, but the great majority of viruses isolated from such lesions produce only limited cell fusion in tissue culture. Because of this, HSV laboratory strains that produce extensive cell fusion (syncytium formation) in culture are regarded as variants or mutants. Furthermore, the rarity of clinical isolates able to produce syncytia in culture suggests that extensive cell fusion is deleterious in vivo. Mutations that confer a syncytial phenotype can then be regarded as bypassing a mechanism that normally limits cell fusion. Determination of how these mutations, some of which are in the cytoplasmic tail of glycoprotein B (gB), lead to syncytium formation will likely reveal how fusion is controlled. Here we show the following. (i) Truncation of the cytoplasmic tail of HSV type 2 gB (gB-2) by a minimum of 25 residues or a maximum of 49 residues produces a syncytial phenotype. (ii) Truncation by 20 to 49 residues increases cell fusion when gB-2 is coexpressed with only gD-2, gH-2, and gL-2. (iii) Truncation by 25 or more residues removes a potential endocytosis motif and increases gB-2 cell surface expression. (iv) Mutation of this motif increases gB-2 cell surface expression but does not increase fusogenic activity, whereas mutation of another potential endocytosis motif does not increase surface expression but does increase fusogenic activity. Therefore, syncytial mutations in the cytoplasmic tail of gB-2 do not act by increasing cell surface levels of the protein.
Genetic Requirements for Homologous Recombination in
Autographa californica
Nucleopolyhedrovirus
Authors: Crouch Erin A. , Passarelli A. Lorena 
Published: October 2002

ABSTRACT

It is known that baculovirus infection promotes high-frequency recombination between its genomes and plasmid DNA during the construction of recombinant viruses for foreign gene expression. However, little is known about the viral genes necessary to promote homologous recombination (HR). We developed an assay to identify viral genes that are necessary to stimulate HR. In this assay, we used two plasmids containing extensive sequence homology that yielded a visible and quantifiable phenotype if HR occurred. The plasmids contained the green fluorescent protein gene (
gfp
) that was mutated at either the N or the C terminus and a viral origin of DNA replication. When the plasmids containing these mutant
gfp
genes were transfected into insect cells alone or together, few green fluorescent protein (GFP)-positive cells were observed, confirming that the host cell machinery alone was not able to promote high levels of HR. However, if viral DNA or viral genes involved in DNA replication were cotransfected into cells along with the mutant
gfp
-containing plasmids, a dramatic increase in GFP-positive cells was observed. The viral genes
ie-1
,
ie-2
,
lef-7
, and
p35
were found to be important for efficient HR in the presence of all other DNA replication genes. However,
ie-1
and
ie-2
were sufficient to promote HR in the absence of other viral genes. Recombination substrates lacking a viral origin of replication had similar genetic requirements for recombination but were less dependent on
ie-1
. Interestingly, even though HR was stimulated by the presence of a viral origin of DNA replication, virally stimulated HR could proceed in the presence of the DNA synthesis inhibitor aphidicolin.
Overexpression of Promyelocytic Leukemia Protein Precludes the Dispersal of ND10 Structures and Has No Effect on Accumulation of Infectious Herpes Simplex Virus 1 or Its Proteins
Authors: Lopez Pascal , Jacob Robert J. , Roizman Bernard 
Published: October 2002

ABSTRACTA key early event in the replication of herpes simplex virus 1 (HSV-1) is the localization of infected-cell protein no. 0 (ICP0) in nuclear structures knows as ND10 or promyelocytic leukemia oncogenic domains (PODs). This is followed by dispersal of ND10 constituents such as the promyelocytic leukemia protein (PML), CREB-binding protein (CBP), and Daxx. Numerous experiments have shown that this dispersal is mediated by ICP0. PML is thought to be the organizing structural component of ND10. To determine whether the virus targets PML because it is inimical to viral replication, telomerase-immortalized human foreskin fibroblasts and HEp-2 cells were transduced with wild-type baculovirus or a baculovirus expressing theMr69,000 form of PML. The transduced cultures were examined for expression and localization of PML in mock-infected and HSV-1-infected cells. The results obtained from studies of cells overexpressing PML were as follows. (i) Transduced cells accumulate large amounts of unmodified and SUMO-I-modified PML. (ii) Mock-infected cells exhibited enlarged ND10 structures containing CBP and Daxx in addition to PML. (iii) In infected cells, ICP0 colocalized with PML in ND10 early in infection, but the two proteins did not overlap or were juxtaposed in orderly structures. (iv) The enlarged ND10 structures remained intact at least until 12 h after infection and retained CBP and Daxx in addition to PML. (v) Overexpression of PML had no effect on the accumulation of viral proteins representative of α, β, or γ groups and had no effect on the accumulation of infectious virus in cells infected with wild-type virus or a mutant (R7910) from which the α0 genes had been deleted. These results indicate the following: (i) PML overexpressed in transduced cells cannot be differentiated from endogenous PML with respect to sumoylation and localization in ND10 structures. (ii) PML does not affect viral replication or the changes in the localization of ICP0 through infection. (iii) Disaggregation of ND10 structures is not an obligatory event essential for viral replication.
Development of a Human Neuronal Cell Model for Human Immunodeficiency Virus (HIV)-Infected Macrophage-Induced Neurotoxicity: Apoptosis Induced by HIV Type 1 Primary Isolates and Evidence for Involvement of the Bcl-2/Bcl-xL-Sensitive Intrinsic Apoptosis Pathway
Authors: Chen Wei , Sulcove Jerrold , Frank Ian , Jaffer Salman , Ozdener Hakan , Kolson Dennis L. 
Published: October 2002

ABSTRACTNeuronal apoptosis within the central nervous system (CNS) is a characteristic feature of AIDS dementia, and it represents a common mechanism of neuronal death induced by neurotoxins (e.g., glutamate) released from human immunodeficiency virus (HIV)-infected macrophages (HIV/macrophage-induced neurotoxicity). Neuronal apoptosis may result from activation of the intrinsic (mitochondrial/bcl-2regulated) or extrinsic (death receptor) pathways, although which pathway predominates in CNS HIV infection is unknown. Apoptosis initiated by the intrinsic pathway is typically blocked by antiapoptosis Bcl-2 family proteins, such as Bcl-2 and Bcl-xL, but whether these can block HIV/macrophage-induced neuronal apoptosis is unknown. To determine the potential role of the Bcl-2 family in HIV/macrophage-induced neuronal apoptosis, we developed a unique in vitro model, utilizing the NT2 neuronal cell line, primary astrocytes and macrophages, and primary CNS HIV type 1 (HIV-1) isolates. We validated our model by demonstrating that NT2.N neurons are protected against HIV-infected macrophages byN-methyl-d-aspartate (NMDA) glutamate receptor antagonists, similar to effects seen in primary neurons. We then established stable NT2.N neuronal lines that overexpress Bcl-2 or Bcl-xL (NT2.N/bcl-2 and NT2.N/bcl-xL, respectively) and determined their sensitivity to macrophages infected with primary R5, X4, and R5/X4 HIV-1 isolates. We found that NT2.N/bcl-2 and NT2.N/bcl-xL neurons were resistant to apoptosis induced by either R5, X4, or R5/X4 isolates and that resistance was abrogated by a Bcl-2 antagonist. Thus, the NMDA receptor/bcl-2-regulated apoptotic pathway contributes significantly to HIV/macrophage-induced neuronal apoptosis, and Bcl-2 family proteins protect neurons against the spectrum of primary HIV-1 isolates. Modulation ofbcl-2gene expression may therefore offer adjunctive neuroprotection against development of AIDS dementia.
Compartmentalization of Surface Envelope Glycoprotein of Human Immunodeficiency Virus Type 1 during Acute and Chronic Infection
Authors: Zhang Linqi , Rowe Leslie , He Tian , Chung Chris , Yu Jian , Yu Wenjie , Talal Andrew , Markowitz Marty , Ho David D. 
Published: October 2002

ABSTRACT
Human immunodeficiency virus type 1 is characterized by extensive genetic heterogeneity. Having previously demonstrated that, in the peripheral blood, the initial viral population is more homogeneous than at subsequent stages of infection, we have extended our studies to tissue samples, allowing comparisons between viral populations in peripheral blood and tissues during both the acute and chronic stages of infection. We found that homogeneity in gp120 sequences during the acute infection phase is not just restricted to the peripheral blood but also extends to other tissue compartments. However, in chronically infected individuals, heterogeneous and distinct viral populations were found in different compartments. We therefore conclude that the dominant and homogeneous viral population observed during the acute infection phase is likely to infiltrate lymphoid tissues and form the genetic bases for subsequent diversification. It is therefore likely that the compartmentalization of viral sequences observed in chronically infected patients reflects a gradual diversification of a common dominant viral variant rather than the preferential migration of distinct viral populations to different tissue compartments at the beginning of infection.
Interaction with Decay-Accelerating Factor Facilitates Coxsackievirus B Infection of Polarized Epithelial Cells
Authors: Shieh Joseph T. C. , Bergelson Jeffrey M. 
Published: October 2002

ABSTRACT
All coxsackie B (CB) viruses can initiate infection by attaching to the coxsackievirus and adenovirus receptor (CAR). Although some CB isolates also bind to decay-accelerating factor (DAF), the role of DAF interaction during infection remains uncertain. We recently observed that CAR in polarized epithelial cells is concentrated at tight junctions, where it is relatively inaccessible to virus. In the experiments reported here we found that, unlike CAR, DAF was present on the apical surface of polarized cells and that DAF-binding isolates of CB3 and CB5 infected polarized epithelial cells more efficiently than did isolates incapable of attaching to DAF. Virus attachment and subsequent infection of polarized cells by DAF-binding isolates were prevented in the presence of anti-DAF antibody. Serial passage on polarized cell monolayers selected for DAF-binding virus variants. Taken together, these results indicate that interaction with DAF on the apical surface of polarized epithelial cells facilitates infection by a subset of CB virus isolates. The results suggest a possible role for DAF in infection of epithelial cells at mucosal surfaces.
A Recombinant Rhesus Cytomegalovirus Expressing Enhanced Green Fluorescent Protein Retains the Wild-Type Phenotype and Pathogenicity in Fetal Macaques
Authors: Chang W. L. William , Tarantal Alice F. , Zhou Shan Shan , Borowsky Alexander D. , Barry Peter A. 
Published: October 2002

ABSTRACTTo facilitate identification of rhesus cytomegalovirus (RhCMV)-infected cells, a recombinant virus expressing enhanced green fluorescent protein (EGFP), designated RhCMV-EGFP, was constructed. An expression cassette for EGFP under the control of the simian virus 40 (SV40) early promoter was inserted into the intergenic region between unique short 1 (US1) and US2 of the RhCMV genome by homologous recombination. RhCMV-EGFP exhibited comparable growth kinetics to that of wild-type virus in rhesus fibroblast cultures and retained its pathogenicity in monkey fetuses. Typical neurologic syndromes caused by CMV infection were observed in all fetuses experimentally inoculated with RhCMV-EGFP, as evidenced by sonographic and gross examinations. Systemic RhCMV infections were established in all fetuses, as viral antigen was detected in multiple organs and virus was isolated from fetal blood samples. The engineered viral genome was stable following rapid serial passages in vitro and multiple rounds of replication in vivo. Infected cells could be readily distinguished by green fluorescence both in tissue cultures and in the fetuses. In addition, EGFP expression was detected in various cell types that were permissive to RhCMV infection, consistent with a broad tissue tropism of the SV40 promoter. These results demonstrate that RhCMV can be successfully engineered without loss of wild-type replication and pathogenic potential. Further, the spectrum of cortical anomalies and the distribution of infected cells in the brain tissues indicated that RhCMV may have preferentially targeted immature neuronal cells. The pattern of RhCMV infection in the central nervous system may offer an explanation for the severe developmental outcomes associated with congenital human CMV infection early in gestation.
Circadian effects on the acute responses of salivary cortisol and IgA in well trained swimmers
Authors: Dimitriou L , Sharp N C C , Doherty M 
Published: October 2002

Objective: To examine whether time of day significantly affects salivary cortisol and IgA levels before and after submaximal swimming.Methods: Fourteen male competitive swimmers (mean (SD) age 18 (3.2) years) volunteered to participate in the study. In a fully randomised, cross over design, each subject performed 5 × 400 m front crawl at 85 (1.2)% of their seasonal best time (277 (16) seconds), with one minute rest between each 400 m, at 0600 and 1800 hours on two separate days. Timed, unstimulated saliva samples were collected before and after exercise. Saliva samples were analysed for cortisol and IgA by radioimmunoassay and single radial immunodiffusion respectively.Results: Significant time of day effects (am and pm respectively) were observed in IgA concentration (0.396 (0.179)v0.322 (0.105) mg/ml, p<0.05), IgA secretory rate (0.109 (0.081)v0.144 (0.083) mg/min, p<0.01), and saliva flow rate (0.31 (0.23)v0.46 (0.22) ml/min, p<0.001) before exercise (all values mean (SD)). Differences in cortisol levels before exercise (1.09 (0.56)v0.67 (0.94) μg/dl) approached significance (p = 0.059). The exercise protocol did not significantly affect IgA concentration and secretory rate (p>0.05) but, in comparison with values before exercise, caused significant alterations in cortisol (p<0.01) and saliva flow rate (p<0.01). There was no significant interaction effect of time of day by exercise on any salivary variables measured (p>0.05). However, most of the values of the salivary variables before exercise were significantly inversely related to their exercise induced response (p<0.05).Conclusion: These results suggest a significant circadian variation in the variables measured before exercise, without showing a significant effect on their acute responses to exercise.
Citrulline/malate promotes aerobic energy production in human exercising muscle
Authors: Bendahan D , Mattei J P , Ghattas B , Confort-Gouny S , Le Guern M E , Cozzone P J 
Published: October 2002

Background: Previous studies have shown an antiasthenic effect of citrulline/malate (CM) but the mechanism of action at the muscular level remains unknown.Objective: To investigate the effects of CM supplementation on muscle energetics.Methods: Eighteen men complaining of fatigue but with no documented disease were included in the study. A rest-exercise (finger flexions)-recovery protocol was performed twice before (D−7 and D0), three times during (D3, D8, D15), and once after (D22) 15 days of oral supplementation with 6 g/day CM. Metabolism of the flexor digitorum superficialis was analysed by31P magnetic resonance spectroscopy at 4.7 T.Results: Metabolic variables measured twice before CM ingestion showed no differences, indicating good reproducibility of measurements and no learning effect from repeating the exercise protocol. CM ingestion resulted in a significant reduction in the sensation of fatigue, a 34% increase in the rate of oxidative ATP production during exercise, and a 20% increase in the rate of phosphocreatine recovery after exercise, indicating a larger contribution of oxidative ATP synthesis to energy production. Considering subjects individually and variables characterising aerobic function, extrema were measured after either eight or 15 days of treatment, indicating chronological heterogeneity of treatment induced changes. One way analysis of variance confirmed improved aerobic function, which may be the result of an enhanced malate supply activating ATP production from the tricarboxylic acid cycle through anaplerotic reactions.Conclusion: The changes in muscle metabolism produced by CM treatment indicate that CM may promote aerobic energy production.
An international comparison of childhood injuries in Hong Kong
Authors: Chan Charles C , Cheng J C Y , Wong T W , Chow C B , Luis Ben P K , Cheung W L , Chan Kevin 
Published: October 2002

Objectives—This study describes 7813 childhood injuries in Shatin, Hong Kong. Supplementary analyses include developmental specificity of external causes and comparison with international childhood injury data.Methods—Children aged 0–15 attending the accident and emergency (A&E) department of the Prince of Wales Hospital in Hong Kong were recruited for the study. Attendance records of participants from the A&E department were analyzed. Details concerning the injury, including theInternational Classification of Diseases, ninth revision, external cause of injury (E code), nature of injury (N code), abbreviated injury scale, and injury severity scale constitute core measurements, along with participants' age, gender, and respective A&E procedural data.Results—Males (65.7%) and fall related injuries (44.2%) predominate, while contusion (34.6%) is the prevailing nature of injury. Two age external cause dimensions are derived from a correspondence analysis. Children 0–1 years old are associated with falls, poisoning, scalds, and machinery related injury. Adolescents aged 12–15 are associated with motor related injury, animal related injury, and cuts/piercings. In comparison with international data, unintentional child injuries in Hong Kong comprised more falls but fewer poisonings and burns.Conclusion—A large proportion of falls, along with low proportion of poisonings and burns, are characteristics of childhood injury profile in Hong Kong. From the results of age external cause correspondence analysis, prevention strategies for different external cause should be developmentally specific.
International comparisons of child injuries and prevention programs: recommendations for an improved prevention program in Germany
Authors: Ellsäβer G , Berfenstam R 
Published: October 2002

Objectives—To compare child injury mortality in Germany with that of four neighboring countries, and to examine injury prevention models in these countries with a view to improving prevention programs in Germany.Methods—Based on official cause of death certificates, child injury mortality rates in Germany are compared with those of Austria, the Netherlands, Sweden, and Switzerland. The main structures and funding of injury prevention programs in these countries are described.Results—In all five countries, mortality is highest among children aged 1–4 years for home and leisure accidents and drownings. Transport accidents are the main cause of death in the 5–14 age group. Mortality in both age groups has fallen significantly since 1980, most markedly in Sweden and the Netherlands.Conclusion—Drawing on the injury mortality data and experience of the comparison countries, the following recommendations are proposed to further reduce home and leisure injuries among children in Germany: (1) establish a soundly funded, central institution responsible for child injury surveillance, research, and the coordination of injury prevention activities, (2) improve product control legislation, and (3) disseminate specific safety information to target groups and the general public.
Parental attitudes regarding interviews about injuries to their children
Authors: Scheidt Peter C , Brenner Ruth A , Rossi Maryann W , Clyman Robert , Boyle Kerrie E 
Published: October 2002

Background—Questions about the circumstances of injuries, especially to infants and young children, might be perceived by parents as threatening or intrusive. Some institutional research review committees express concerns that interviews about childhood injuries may be offensive to parents. The perceived value and potential risk of questions about a young child's injury could affect the quality of responses.Objectives—To assess parents' perceptions of threat and value of interviews about injury to their young children.Setting—District of Columbia, 1 October 1995 to 30 September 1996.Methods—Trained research assistants telephoned the parents of children seen in an emergency department or admitted to the hospital after an injury. To be eligible for inclusion the child must have been <3 years of age and a resident of the District of Columbia at the time of the event. After collection of sociodemographic information and circumstances of injury, the respondents were asked if the interview caused them to feel angry, offended or threatened, and if participation in the study was considered worthwhile.Results—Seventy eight per cent of eligible families were contacted. Among those contacted, 93% completed the interview. Eighty two per cent of respondents were mothers and 11% fathers. Ninety per cent (95% confidence interval (CI) 88.4 to 91.6) of the respondents reported that the interview did not make them feel angry, offended, or threatened. Only 13 (1%; 95% CI 0.5 to 1.5) reported being very angry and 7.1% (95% CI 5.8 to 8.5) reported being a little angry. The majority of participants (61.2%, 95% CI 58.6 to 63.8) felt that participation in the study was definitely worthwhile and only 5.5 % (95% CI 4.3 to 6.7) felt that it was not at all worthwhile. Parents of children with intentional injuries were more likely to report feelings of anger than parents of children with unintentional injuries (24%v8 %; p=0.02). The per cent of respondents reporting any anger was greater when the interview was conducted within 14 days of the hospital visit compared with later interviews (11%v7 %; p=0.02).Conclusions—In similar populations most parents of young, injured children are neither upset nor threatened by interviews that probe for details about how their children become injured. In general, collecting data aimed to prevent injuries is perceived as worthwhile, and parents readily cooperate with providing this information. Investigators and review committees should consider that interviews about infant and young child injuries are of no or minimal risk.