bluuebunny/crossref_metadata_2025 huggingface dataset:
Lateral Flow Immunoassay for Diagnosis of
Trypanosoma cruzi
Infection with High Correlation to the Radioimmunoprecipitation Assay
Authors: Houghton Raymond L. , Stevens Yvonne Y. , Hjerrild Kathryn , Guderian Jeff , Okamoto Masahiko , Kabir Mazbahul , Reed Steven G. , Leiby David A. , Morrow W. John W. , Lorca Myriam , Raychaudhuri Syamal
Published: February 2009

The incidence of blood donors seropositive for
Trypanosoma cruzi
in North America has increased with population migration and more rigorous surveillance. The United States, considered nonendemic for
T. cruzi
, could therefore be at risk to exposure to parasite transmission through blood or organ donations. Current tests show variable reactivity, especially with Central American sera. Here we describe the development of a lateral flow immunoassay for the rapid detection of
T. cruzi
infection that has a strong correlation to the radioimmunoprecipitation assay (RIPA) “gold standard” in the United States. Such a test could have utility in small blood banks for prescreening donors, as well as in cardiac transplantation evaluation.
T. cruzi
consensus and/or RIPA-positive sera from Central and South America were evaluated in enzyme immunoassays (EIAs). These included commercial panels from Boston Biomedica, Inc. (BBI) (
n
= 14), and HemaBio (
n
= 21). Other sources included RIPA-positive sera from the American Red Cross (ARC) (
n
= 42), as well as from Chile. Sera were tested with the multiepitope recombinant TcF. All but one of the BBI samples were positive and 7 of 21 HemaBio samples and 6 of 42 ARC samples were low positive or negative. This observation indicated the need for additional antigens. To complement TcF reactivity, we tested the sera with peptides 30, 36, SAPA, and 1.1, 1.2, and 1.3 His fragments of 85-kDa trans-sialidase. We identified a promising combination of the tested antigens and constructed a single recombinant protein, ITC6, that enhanced the relative sensitivity in U.S. blood donor sera compared to that of TcF. The data on its evaluation using RIPA-confirmed positive sera in EIA and lateral flow immunoassay studies are presented, along with an additional recombinant protein, ITC8.2, with two additional sequences for peptide 1 and Kmp-11. The latter, when evaluated in a dipstick assay with consensus positive sera, had a sensitivity of 99.2% and a specificity of 99.1%.
Molecular Epidemiological Investigation of a Nosocomial Outbreak of Human Metapneumovirus Infection in a Pediatric Hemato-Oncology Patient Population
Authors: Kim Sollip , Sung Heungsup , Im Ho Joon , Hong Soo-Jong , Kim Mi-Na
Published: February 2009

We report the first nosocomial outbreak of human metapneumovirus (hMPV) infection in a pediatric patient population. Among 15 pediatric hMPV infections from March to May 2007, there was a nosocomial outbreak involving two patients sharing a room in a hemato-oncology ward with a patient with a community-acquired case of hMPV infection. The estimated incubation period was 7 to 9 days for a symptomatic nosocomial case. Sequencing of fusion genes of 15 isolates revealed two clusters belonging to subgroup A2 and one cluster belonging to subgroup B2. Three isolates from the outbreak had sequences identical to those of samples in the A2 cluster. There was also a separate nosocomial case represented by the B2 cluster.
Presence and Molecular Epidemiology of Virulence Factors in Methicillin-Resistant
Staphylococcus aureus
Strains Colonizing and Infecting Soldiers
Authors: Ellis Michael W. , Griffith Matthew E. , Jorgensen James H. , Hospenthal Duane R. , Mende Katrin , Patterson Jan E.
Published: February 2009

Methicillin-resistant
Staphylococcus aureus
(MRSA) has emerged as an important cause of skin and soft-tissue infections (SSTI). The understanding of the molecular epidemiology and virulence of MRSA continues to expand. From January 2005 to December 2005, we screened soldiers for MRSA nasal colonization, administered a demographic questionnaire, and monitored them prospectively for SSTI. All MRSA isolates underwent molecular analysis, which included pulsed-filed gel electrophoresis (PFGE) and PCR for Panton-Valentine leukocidin (PVL), the arginine catabolic mobile element (ACME), and the staphylococcal cassette chromosome
mec
(SCC
mec
). Of the 3,447 soldiers screened, 134 (3.9%) had MRSA colonization. Of the 3,066 (89%) who completed the study, 39 developed culture-confirmed MRSA abscesses. Clone USA300 represented 53% of colonizing isolates but was responsible for 97% of the abscesses (
P
< 0.001). Unlike colonizing isolates, isolates positive for USA300, PVL, ACME, and type IV SCC
mec
were significantly associated with MRSA abscess isolates. As determined by multivariate analysis, risk factors for MRSA colonization were a history of SSTI and a history of hospitalization. Although various MRSA strains may colonize soldiers, USA300 is the most virulent when evaluated prospectively, and PVL, ACME, and type IV SCC
mec
are associated with these abscesses.
Intercellular Adhesion Molecule 1 (ICAM-1), but Not ICAM-2 and -3, Is Important for Dendritic Cell-Mediated Human Immunodeficiency Virus Type 1 Transmission
Authors: Wang Jian-Hua , Kwas Constance , Wu Li
Published: February 2009

Dendritic cells (DCs) play a critical role in cell-to-cell-mediated transmission of human immunodeficiency virus type 1 (HIV-1). Interactions between intercellular adhesion molecules (ICAMs) and their ligands facilitate DC-T-cell contact. The interaction between ICAM-1 on DCs and leukocyte function-associated molecule 1 (LFA-1) on CD4+T cells has been proposed to be important for DC-mediated HIV-1 transmission. Given that DCs and T cells express multiple ICAMs and binding ligands, the relative importance of ICAMs in DC-mediated HIV-1 transmission remains to be defined. Here, we examine the role of ICAM-1, -2, and -3 in DC-mediated HIV-1 transmission to various types of target cells including primary CD4+T cells. The expression levels of ICAMs and their ligands on immature and mature DCs and various types of HIV-1 target cells were measured by flow cytometry. Blocking ICAM-1 in DCs with specific monoclonal antibodies and small interfering RNA impaired DC-mediated HIV-1 transmission. DC-mediated viral transmission was significantly inhibited when both ICAM-1 on DCs and LFA-1 on CD4+T cells were blocked. However, blockade of ICAM-1 on target cells did not significantly inhibit DC-mediated HIV-1 transmission. Ectopic expression and antibody blocking suggest that DC-mediated HIV-1 transmission to primary CD4+T cells is independent of ICAM-2 and ICAM-3. Taken together, our data clarified the role of ICAMs in DC-mediated HIV-1 transmission to CD4+T cells.
Components of Nuclear Domain 10 Bodies Regulate Varicella-Zoster Virus Replication
Authors: Kyratsous Christos A. , Silverstein Saul J.
Published: February 2009

PML, Sp100, and Daxx are proteins that normally reside within nuclear domains 10 (ND10s). They associate with DNA virus genomes and repress the very early stages of the DNA virus replication cycle. Virus-encoded proteins counteract this innate antiviral response. ICP0, a herpes simplex virus (HSV) immediate-early protein, is necessary and sufficient to dissociate ND10s and target their two major components, PML and Sp100, for proteasomal degradation. In this report, we show that ORF61p, the varicella-zoster virus (VZV) ortholog of ICP0, does not degrade PML and alters Sp100 levels only slightly. Furthermore, we demonstrate that other virus proteins cannot substitute for this lack of function during infection. By using short interfering RNAs, we depleted PML, Sp100, and Daxx and studied their roles in plaquing efficiency, virus protein accumulation, infectious-center titer, and virus spread. The results of these studies show that components of ND10s can accelerate VZV replication but do not ultimately control cell-associated virus titers. We conclude that while both ICP0 and ORF61p activate virus gene expression, they modulate host innate repression mechanisms in two different ways. As a result, HSV and VZV commandeer their host cells by distinct mechanisms to ensure their replication and spread.
Replication-Deficient Ebolavirus as a Vaccine Candidate
Authors: Halfmann Peter , Ebihara Hideki , Marzi Andrea , Hatta Yasuko , Watanabe Shinji , Suresh M. , Neumann Gabriele , Feldmann Heinz , Kawaoka Yoshihiro
Published: February 2009

Ebolavirus causes severe hemorrhagic fever, with case fatality rates as high as 90%. Currently, no licensed vaccine is available against Ebolavirus. We previously generated a replication-deficient, biologically contained Ebolavirus, EbolaΔVP30, which lacks the essential VP30 gene, grows only in cells stably expressing this gene product, and is genetically stable. Here, we evaluated the vaccine potential of EbolaΔVP30. First, we demonstrated its safety in STAT-1-knockout mice, a susceptible animal model for Ebolavirus infection. We then tested its protective efficacy in two animal models, mice and guinea pigs. Mice immunized twice with EbolaΔVP30 were protected from a lethal infection of mouse-adapted Ebolavirus. Virus titers in the serum of vaccinated mice were significantly lower than those in nonvaccinated mice. Protection of mice immunized with EbolaΔVP30 was associated with a high antibody response to the Ebolavirus glycoprotein and the generation of an Ebolavirus NP-specific CD8
+
T-cell response. Guinea pigs immunized twice with EbolaΔVP30 were also protected from a lethal infection of guinea pig-adapted Ebolavirus. Our study demonstrates the potential of the EbolaΔVP30 virus as a new vaccine platform.
Poxvirus Host Range Protein CP77 Contains an F-Box-Like Domain That Is Necessary To Suppress NF-κB Activation by Tumor Necrosis Factor Alpha but Is Independent of Its Host Range Function
Authors: Chang Shu-Jung , Hsiao Jye-Chian , Sonnberg Stephanie , Chiang Cheng-Ting , Yang Min-Hsiang , Tzou Der-Lii , Mercer Andrew A. , Chang Wen
Published: February 2009

Tumor necrosis factor alpha (TNF-α) activates the nuclear factor κB (NF-κB) signaling pathway that regulates expression of many cellular factors playing important roles in innate immune responses and inflammation in infected hosts. Poxviruses employ many strategies to inhibit NF-κB activation in cells. In this report, we describe a poxvirus host range protein, CP77, which blocked NF-κB activation by TNF-α. Immunofluorescence analyses revealed that nuclear translocation of NF-κB subunit p65 protein in TNF-α-treated HeLa cells was blocked by CP77. CP77 did so without blocking IκBα phosphorylation, suggesting that upstream kinase activation was not affected by CP77. Using GST pull-down, we showed that CP77 bound to the NF-κB subunit p65 through the N-terminal six-ankyrin-repeat region in vitro. CP77 also bound to Cullin-1 and Skp1 of the SCF complex through a C-terminal 13-amino-acid F-box-like sequence. Both regions of CP77 are required to block NF-κB activation. We thus propose a model in which poxvirus CP77 suppresses NF-κB activation by two interactions: the C-terminal F-box of CP77 binding to the SCF complex and the N-terminal six ankyrins binding to the NF-κB subunit p65. In this way, CP77 attenuates innate immune response signaling in cells. Finally, we expressed CP77 or a CP77 F-box deletion protein from a vaccinia virus host range mutant (VV-hr-GFP) and showed that either protein was able to rescue the host range defect, illustrating that the F-box region, which is important for NF-κB modulation and binding to SCF complex, is not required for CP77's host range function. Consistently, knocking down the protein level of NF-κB did not relieve the growth restriction of VV-hr-GFP in HeLa cells.
A Chimeric A2 Strain of Respiratory Syncytial Virus (RSV) with the Fusion Protein of RSV Strain Line 19 Exhibits Enhanced Viral Load, Mucus, and Airway Dysfunction
Authors: Moore Martin L. , Chi Michael H. , Luongo Cindy , Lukacs Nicholas W. , Polosukhin Vasiliy V. , Huckabee Matthew M. , Newcomb Dawn C. , Buchholz Ursula J. , Crowe James E. , Goleniewska Kasia , Williams John V. , Collins Peter L. , Peebles R. Stokes
Published: February 2009

Respiratory syncytial virus (RSV) is the leading cause of respiratory failure and viral death in infants. Abundant airway mucus contributes to airway obstruction in RSV disease. Interleukin-13 (IL-13) is a mediator of pulmonary mucus secretion. It has been shown that infection of BALB/c mice with the RSV line 19 strain but not with the RSV A2 laboratory strain results in lung IL-13 and mucus expression. Here, we sequenced the RSV line 19 genome and compared it to the commonly used A2 and Long strains. There were six amino acid differences between the line 19 strain and both the A2 and Long RSV strains, five of which are in the fusion (F) protein. The Long strain, like the A2 strain, did not induce lung IL-13 and mucus expression in BALB/c mice. We hypothesized that the F protein of RSV line 19 is more mucogenic than the F proteins of A2 and Long. We generated recombinant, F-chimeric RSVs by replacing the F gene of A2 with the F gene of either line 19 or Long. Infection of BALB/c mice with RSV rA2 line 19F resulted in lower alpha interferon lung levels 24 h postinfection, higher lung viral load, higher lung IL-13 levels, greater airway mucin expression levels, and greater airway hyperresponsiveness than infection with rA2-A2F or rA2-LongF. We identified the F protein of RSV line 19 as a factor that plays a role in pulmonary mucin expression in the setting of RSV infection.
Kinetics of Immune Responses to Influenza Virus-Like Particles and Dose-Dependence of Protection with a Single Vaccination
Authors: Quan Fu Shi , Yoo Dae-Goon , Song Jae-Min , Clements John D. , Compans Richard W. , Kang Sang-Moo
Published: February 2009

The format of influenza virus-like particles (VLPs) as a nonreplicating particulate vaccine candidate is a promising alternative to conventional egg-based vaccines. In this study, we have investigated the detailed kinetics of immune responses and protective efficacy after a single intranasal immunization with different doses of VLPs alone or in the presence of anEscherichia colimutant heat-labile enterotoxin [mLT(R192G)] or cholera toxin subunit B as adjuvants. Analysis of immune responses showed differential kinetics in a VLP antigen dose-dependent manner and dynamic changes in the ratios of antibody immunoglobulin G isotypes over the time course. Protection against lethal challenge was observed with a single immunization with influenza VLPs even without adjuvant. The addition of adjuvant showed significant antigen-sparing effects with improved protective efficacy. The protective immune responses, efficacies of protection, and antigen-sparing effects were significantly improved by a second immunization as determined by the levels of neutralizing antibodies, morbidity postchallenge, lung viral titers, and inflammatory cytokines. Our results are informative for a better understanding of the protective immunity induced by a single dose or two doses of influenza VLPs, which is dependent on antigen dosage and the presence of adjuvant, and will provide insights into designing effective vaccines based on VLPs.
Differential Modification of Interferon Regulatory Factor 3 following Virus Particle Entry
Authors: Noyce Ryan S. , Collins Susan E. , Mossman Karen L.
Published: February 2009

Viral infection elicits the activation of numerous cellular signal transduction pathways, leading to the induction of both innate and adaptive immune responses in the host. In particular, interferon regulatory factor 3 (IRF3) has been shown to be essential for the induction of an antiviral response. Current models suggest that virus replication causes phosphorylation of C-terminal serine and threonine residues on IRF3, leading to its dimerization and translocation to the nucleus, where it activates interferon. Upon entry of replication-deficient Newcastle disease virus (NDV) particles, however, we failed to detect IRF3 dimerization or hyperphosphorylation, despite robust interferon-stimulated gene (ISG) and antiviral state induction and confirmation by small interfering RNA knockdown that IRF3 is essential for this response. To further compare the effects of various viruses and their replication status on IRF3 activation and to determine the minimal posttranslational modification required for IRF3 activation, two-dimensional gel electrophoresis and native polyacrylamide gel electrophoresis were employed. However, we failed to identify a minimal posttranslational modification of IRF3 that correlated with downstream biological activity, and the extent of posttranslational modification observed on IRF3 did not correlate with the degree of subsequent ISG induction. Thus, current techniques used to detect IRF3 activation are insufficient to infer its role in mediating downstream biological response induction and should be utilized with caution.
NSs Protein of Rift Valley Fever Virus Induces the Specific Degradation of the Double-Stranded RNA-Dependent Protein Kinase
Authors: Habjan Matthias , Pichlmair Andreas , Elliott Richard M. , Överby Anna K. , Glatter Timo , Gstaiger Matthias , Superti-Furga Giulio , Unger Hermann , Weber Friedemann
Published: February 2009

Rift Valley fever virus (RVFV) continues to cause large outbreaks of acute febrile and often fatal illness among humans and domesticated animals in Africa, Saudi Arabia, and Yemen. The high pathogenicity of this bunyavirus is mainly due to the viral protein NSs, which was shown to prevent transcriptional induction of the antivirally active type I interferons (alpha/beta interferon [IFN-α/β]). Viruses lacking the NSs gene induce synthesis of IFNs and are therefore attenuated, whereas the noninducing wild-type RVFV strains can only be inhibited by pretreatment with IFN. We demonstrate here in vitro and in vivo that a substantial part of the antiviral activity of IFN against RVFV is due to a double-stranded RNA-dependent protein kinase (PKR). PKR-mediated virus inhibition, however, was much more pronounced for the strain Clone 13 with NSs deleted than for the NSs-expressing strain ZH548. In vivo, Clone 13 was nonpathogenic for wild-type (wt) mice but could regain pathogenicity if mice lacked the PKR gene. ZH548, in contrast, killed both wt and PKR knockout mice indiscriminately. ZH548 was largely resistant to the antiviral properties of PKR because RVFV NSs triggered the specific degradation of PKR via the proteasome. The NSs proteins of the related but less virulent sandfly fever Sicilian virus and La Crosse virus, in contrast, had no such anti-PKR activity despite being efficient suppressors of IFN induction. Our data suggest that RVFV NSs has gained an additional anti-IFN function that may explain the extraordinary pathogenicity of this virus.
The Adenoviral E1B 55-Kilodalton Protein Controls Expression of Immune Response Genes but Not p53-Dependent Transcription
Authors: Miller Daniel L. , Rickards Brenden , Mashiba Michael , Huang Wenying , Flint S. J.
Published: February 2009

The human adenovirus type 5 (Ad5) E1B 55-kDa protein modulates several cellular processes, including activation of the tumor suppressor p53. Binding of the E1B protein to the activation domain of p53 inhibits p53-dependent transcription. This activity has been correlated with the transforming activity of the E1B protein, but its contribution to viral replication is not well understood. To address this issue, we used microarray hybridization methods to examine cellular gene expression in normal human fibroblasts (HFFs) infected by Ad5, the E1B 55-kDa-protein-null mutant Hr6, or a mutant carrying substitutions that impair repression of p53-dependent transcription. Comparison of the changes in cellular gene expression observed in these and our previous experiments (D. L. Miller et al., Genome Biol. 8:R58, 2007) by significance analysis of microarrays indicated excellent reproducibility. Furthermore, we again observed that Ad5 infection led to efficient reversal of the p53-dependent transcriptional program. As this same response was also induced in cells infected by the two mutants, we conclude that the E1B 55-kDa protein is not necessary to block activation of p53 in Ad5-infected cells. However, groups of cellular genes that were altered in expression specifically in the absence of the E1B protein were identified by consensus k-means clustering of the hybridization data. Statistical analysis of the enrichment of genes associated with specific functions in these clusters established that the E1B 55-kDa protein is necessary for repression of genes encoding proteins that mediate antiviral and immune defenses.
PI3K Signaling Regulates Rapamycin-Insensitive Translation Initiation Complex Formation in Vaccinia Virus-Infected Cells
Authors: Zaborowska Izabela , Walsh Derek
Published: February 2009

How vaccinia virus (VV) regulates assembly of the host translation initiation complex eIF4F remains unclear. Here, we show that VV activated host PI3K to stimulate downstream mammalian target of rapamycin (mTOR), a kinase that inactivates the translational repressor 4E-BP1. However, although the mTOR inhibitor rapamycin suppressed VV-induced inactivation of 4E-BP1, it failed to inhibit eIF4F assembly. In contrast, PI3K inhibition in VV-infected cells increased the abundance of hypophosphorylated 4E-BP1 and disrupted eIF4F complex formation. PI3K signaling, therefore, plays a critical role in regulating protein production during VV infection, at least in part by controlling the abundance and activity of 4E-BP1.
Protein X of Borna Disease Virus Inhibits Apoptosis and Promotes Viral Persistence in the Central Nervous Systems of Newborn-Infected Rats
Authors: Poenisch Marion , Burger Nils , Staeheli Peter , Bauer Georg , Schneider Urs
Published: February 2009

Borna disease virus (BDV) is a neurotropic member of the order
Mononegavirales
with noncytolytic replication and obligatory persistence in cultured cells and animals. Here we show that the accessory protein X of BDV represents the first mitochondrion-localized protein of an RNA virus that inhibits rather than promotes apoptosis induction. Rat C6 astroglioma cells persistently infected with wild-type BDV were significantly more resistant to death receptor-dependent and -independent apoptotic stimuli than uninfected cells or cells infected with a BDV mutant expressing reduced amounts of X. Confocal microscopy demonstrated that X colocalizes with mitochondria and expression of X from plasmid DNA rendered human 293T and mouse L929 cells resistant to apoptosis induction. A recombinant virus encoding a mutant X protein unable to associate with mitochondria (BDV-X
A6A7
) failed to block apoptosis in C6 cells. Furthermore, Lewis rats neonatally infected with BDV-X
A6A7
developed severe neurological symptoms and died around day 30 postinfection, whereas all animals infected with wild-type BDV remained healthy and became persistently infected. TUNEL (terminal deoxynucleotidyltransferase-mediated dUTP-biotin nick end labeling) staining revealed a significant increase in the number of apoptotic cells in the brain of BDV-X
A6A7
-infected animals, whereas the numbers of CD3
+
T lymphocytes were comparable to those detected in animals infected with wild-type BDV. Our data thus indicate that inhibition of apoptosis by X promotes noncytolytic viral persistence and is required for the survival of cells in the central nervous system of BDV-infected animals.
Electroporation of Synthetic DNA Antigens Offers Protection in Nonhuman Primates Challenged with Highly Pathogenic Avian Influenza Virus
Authors: Laddy Dominick J. , Yan Jian , Khan Amir S. , Andersen Hanne , Cohn Amanda , Greenhouse Jack , Lewis Mark , Manischewitz Jody , King Lisa R. , Golding Hana , Draghia-Akli Ruxandra , Weiner David B.
Published: February 2009

Avian influenza highlights the need for novel vaccination techniques that would allow for the rapid design and production of safe and effective vaccines. An ideal platform would be capable of inducing both protective antibodies and potent cellular immune responses. These potential advantages of DNA vaccines remain unrealized due to a lack of efficacy in large animal studies and in human trials. Questions remain regarding the potential utility of cellular immune responses against influenza virus in primates. In this study, by construct optimization and in vivo electroporation of synthetic DNA-encoded antigens, we observed the induction of cross-reactive cellular and humoral immune responses individually capable of providing protection from influenza virus infection in the rhesus macaque. These studies advance the DNA vaccine field and provide a novel, more tolerable vaccine with broad immunogenicity to avian influenza virus. This approach appears important for further investigation, including studies with humans.
Proteasomal Degradation of the Papillomavirus E2 Protein Is Inhibited by Overexpression of Bromodomain-Containing Protein 4
Authors: Gagnon David , Joubert Simon , Sénéchal Hélène , Fradet-Turcotte Amélie , Torre Sabrina , Archambault Jacques
Published: February 2009

The E2 protein of human papillomavirus (HPV) binds to specific sites in the viral genome to regulate its transcription, replication, and maintenance in infected cells. Like most regulatory proteins, E2 is rapidly turned over. A high-throughput assay was developed to quantify the expression and stability of E2 in vivo, based on its fusion toRenillaluciferase (RLuc). The steady-state levels of Rluc-E2 were quantified by measuring the amounts of associated luciferase activity, and its degradation was measured by monitoring the decrease in enzymatic activity occurring after a block of translation with cycloheximide. Using this assay, the E2 proteins from a low-risk (HPV11) and a high-risk (HPV31) human papillomavirus (HPV) type were found to have short half-lives of 60 min in C33A cervical carcinoma cells and to be ubiquitinated and degraded by the proteasome. Analysis of mutant proteins showed that the instability of E2 is independent of its DNA-binding and transcriptional activities but is encoded within its transactivation domain, the region that binds to the cellular chromatin factor bromodomain-containing protein 4 (Brd4) to regulate viral gene transcription. Overexpression of Brd4, or of its C-terminal E2-interaction domain, was found to increase the steady-state levels and stability of wild-type E2 but not of E2 mutants defective for binding Brd4. These results indicate that the stability of E2 is increased upon complex formation with Brd4 and highlight the value of the luciferase assay for the study of E2 degradation.
Major Coexisting Human Immunodeficiency Virus Type 1envGene Subpopulations in the Peripheral Blood Are Produced by Cells with Similar Turnover Rates and Show Little Evidence of Genetic Compartmentalization
Authors: Ince William L. , Harrington Patrick R. , Schnell Gretja L. , Patel-Chhabra Milloni , Burch Christina L. , Menezes Prema , Price Richard W. , Eron Joseph J. , Swanstrom Ronald I.
Published: February 2009

A distinctive feature of chronic human immunodeficiency virus type 1 (HIV-1) infection is the presence of multiple coexisting genetic variants, or subpopulations, that comprise the HIV-1 population detected in the peripheral blood. Analysis of HIV-1 RNA decay dynamics during the initiation of highly active antiretroviral therapy (HAART) has been a valuable tool for modeling the life span of infected cells that produce the bulk HIV-1 population. However, different HIV-1 target cells may have different turnover rates, and it is not clear whether the bulk HIV-1 RNA decay rate actually represents a composite of the decay rates of viral subpopulations compartmentalized in different cellular subsets with different life spans. Using heteroduplex tracking assays targeting the highly variable V3 or V4-V5 regions of the HIV-1envgene in eight subjects, we found that all detectable coexisting HIV-1 variants in the peripheral blood generally decayed at similar rates during the initiation of HAART, suggesting that all of the variants were produced by cells with similar life spans. Furthermore, single genome amplification and coreceptor phenotyping revealed that in two subjects coexisting HIV-1 variants with distinct CXCR4 or CCR5 coreceptor phenotypes decayed with similar rates. Also, in nine additional subjects, recombination and a lack of genetic compartmentalization between X4 and R5 variants were observed, suggesting an overlap in host cell range. Our results suggest that the HIV-1envsubpopulations detectable in the peripheral blood are produced by cells with similar life spans and are not genetically isolated within particular cell types.
Essential Role for either
TRS1
or
IRS1
in Human Cytomegalovirus Replication
Authors: Marshall Emily E. , Bierle Craig J. , Brune Wolfram , Geballe Adam P.
Published: February 2009

Viral infections often produce double-stranded RNA (dsRNA), which in turn triggers potent antiviral responses, including the global repression of protein synthesis mediated by protein kinase R (PKR) and 2′-5′ oligoadenylate synthetase (OAS). As a consequence, many viruses have evolved genes, such as those encoding dsRNA-binding proteins, which counteract these pathways. Human cytomegalovirus (HCMV) encodes two related proteins, pTRS1 and pIRS1, which bind dsRNA and can prevent activation of the PKR and OAS pathways. HCMV mutants lacking either
IRS1
or
TRS1
replicate at least moderately well in cell culture. However, as we demonstrate in the present study, an HCMV mutant lacking both
IRS1
and
TRS1
(HCMV[ΔI/ΔT]) has a severe replication defect. Infection with HCMV[ΔI/ΔT] results in a profound inhibition of overall and viral protein synthesis, as well as increased phosphorylation of eukaryotic initiation factor 2α (eIF2α). The vaccinia virus
E3L
gene can substitute for
IRS1
or
TRS1
, enabling HCMV replication. Despite the accumulation of dsRNA in HCMV-infected cells, the OAS pathway remains inactive, even in HCMV[ΔI/ΔT]-infected cells. These results suggest that PKR-mediated phosphorylation of eIF2α is the dominant dsRNA-activated pathway responsible for inhibition of protein synthesis and HCMV replication in the absence of both
IRS1
and
TRS1
and that the requirement for evasion of the PKR pathway likely explains the necessity for
IRS1
or
TRS1
for productive infection.
Role of Sialic Acid Binding Specificity of the 1918 Influenza Virus Hemagglutinin Protein in Virulence and Pathogenesis for Mice
Authors: Qi Li , Kash John C. , Dugan Vivien G. , Wang Ruixue , Jin Guozhong , Cunningham Robert E. , Taubenberger Jeffery K.
Published: February 2009

The 1918 influenza pandemic caused more than 40 million deaths and likely resulted from the introduction and adaptation of a novel avian-like virus. Influenza A virus hemagglutinins are important in host switching and virulence. Avian-adapted influenza virus hemagglutinins bind sialic acid receptors linked via α2-3 glycosidic bonds, while human-adapted hemagglutinins bind α2-6 receptors. Sequence analysis of 1918 isolates showed hemagglutinin genes with α2-6 or mixed α2-6/α2-3 binding. To characterize the role of the sialic acid binding specificity of the 1918 hemagglutinin, we evaluated in mice chimeric influenza viruses expressing wild-type and mutant hemagglutinin genes from avian and 1918 strains with differing receptor specificities. Viruses expressing 1918 hemagglutinin possessing either α2-6, α2-3, or α2-3/α2-6 sialic acid specificity were fatal to mice, with similar pathology and cellular tropism. Changing α2-3 to α2-6 binding specificity did not increase the lethality of an avian-adapted hemagglutinin. Thus, the 1918 hemagglutinin contains murine virulence determinants independent of receptor binding specificity.
Eccentric loading for Achilles tendinopathy — strengthening or stretching?
Authors: Allison G T , Purdam C
Published: February 2009

The prescription of eccentric loading is considered as a mainstay of non-operative rehabilitation programmes for mid-substance chronic Achilles tendinopathy. Such exercises have some degree of clinical utility in comparison with concentric training and are often referred to as a strengthening programme. Yet the dose parameters of the eccentric loading do not reflect an optimal strengthening programme and specifically avoid the normal eccentric–concentric coupling typical of the stretch shortening cycle. This manuscript identifies the arguments and counterarguments for why eccentric loading rehabilitation is not an optimal strengthening programme. It is proposed that such exercises reflect a specific stretching programme directed at the passive structures. This has two important clinical implications. Firstly, this reinterpretation of the role of eccentric exercises may direct future research into the underlying mechanisms of tendinopathy and, secondly, it may reinforce the importance of adjunct sports specific strengthening programmes.
Secular trends in aerobic fitness performance in 13–18-year-old adolescents from 1976 to 2001
Authors: Huotari P R T , Nupponen H , Laakso L , Kujala U M
Published: February 2009

Objective

To analyse the secular trends in aerobic fitness performance and some of its determinants (body mass index (BMI) and leisure time physical activity (LTPA)) in adolescents.

Design

Cross-sectional population-based studies in 1976 and 2001 in Finland. A stratified random sample of Finnish 13–18-year-old adolescents was studied in 1976 (n = 717; 384 boys and 333 girls) and in 2001 (n = 558; 305 boys and 253 girls). The main outcome measure was aerobic fitness, estimated with a 2000 m (for boys) and 1500 m (for girls) running test; the weight and height of participants were also measured. Self-reported weekly frequency of LTPA of at least 30 min duration and regularity of participation in organised sport were obtained by questionnaire. Identical methods were used in 1976 and 2001.

Results

Running time was longer in 2001 compared to 1976 in boys (56 s, Cohen d = 0.46, medium effect size; p<0.001) and girls (29 s, d = 0.32, small; p<0.01). BMI and participation in LTPA explained more of the variance in aerobic fitness in 2001 than in 1976 in boys and girls.

Conclusions

Aerobic fitness of school-aged children deteriorated between the measurement points. BMI and organised LTPA were better associated with aerobic fitness in 2001 than in 1976. An increase in overweight and obesity was associated with the decrease in aerobic fitness. Although the importance of organised LTPA to fitness increased, it is possible that the decrease in overall physical activity between 1976 and 2001 contributed most to the decrease in the level of aerobic fitness.
The effectiveness of vocationally oriented multidisciplinary intervention on sickness absence and early retirement among employees at risk: an observational study
Authors: Suoyrjö H , Oksanen T , Hinkka K , Kivimäki M , Klaukka T , Pentti J , Vahtera J
Published: February 2009

Objective:

To study the effect of a preventive vocationally oriented intervention on rates of sickness absence and disability pension in employees considered to be at risk of future work disability.

Design:

An observational register-based study of public sector employees.

Subjects:

2236 intervention programme participants and 8944 matched controls were followed up for 8 years.

Methods:

Multidisciplinary intervention was carried out at rehabilitation institutions. Data on demographics and sickness absences were obtained from employers’ records and information about health at baseline, participation in the intervention and subsequent disability pension from national registers.

Results:

Before the intervention participants had 17% more annual sick leave days and a 23% higher rate of absence spells lasting >21 days than controls. In the intervention year and 3 subsequent years, the sickness absence rate among participants reduced to that observed among controls but thereafter increased to the pre-intervention level (p for curvilinear trend <0.001 for absence days and 0.03 for absence spells). The association between the intervention and future disability pension was non-proportional among participants. Compared to controls, risk among participants was lower in the first 4 years of follow-up but thereafter returned to the previous higher level. The temporary decline in sickness absence attributable to the intervention totalled 6673 absence days per 1000 employees and the cumulative reduction in disability was 56.4 years. These direct health benefits may not fully cover the costs of the intervention.

Conclusion:

The risk of work disability can be temporarily reduced in employees at risk by means of a vocationally oriented multidisciplinary intervention programme.
Open source marketing: Camel cigarette brand marketing in the “Web 2.0” world
Authors: Freeman B , Chapman S
Published: February 2009

Background:

The international trend towards comprehensive bans on tobacco advertising has seen the tobacco industry become increasingly innovative in its approach to marketing. Further fuelling this innovation is the rapid evolution and accessibility of web-based technology. The internet, as a relatively unregulated marketing environment, provides many opportunities for tobacco companies to pursue their promotional ambitions.

Methods:

In this paper, “open source marketing” is considered as a vehicle that has been appropriated by the tobacco industry, through a case study of efforts to design the packaging for the Camel Signature Blends range of cigarettes. Four sources are used to explore this case study including a marketing literature search, a web-based content search via the Google search engine, interviews with advertising trade informants and an analysis of the Camel brand website.

Results:

RJ Reynolds (RJR) has proven to be particularly innovative in designing cigarette packaging. RJR engaged with thousands of consumers through their Camel brand website to design four new cigarette flavours and packages. While the Camel Signature Blends packaging designs were subsequently modified for the retail market due to problems arising with their cartoon-like imagery, important lessons arise on how the internet blurs the line between marketing and market research.

Conclusions:

Open source marketing has the potential to exploit advertising ban loopholes and stretch legal definitions in order to generate positive word of mouth about tobacco products. There are also lessons in the open source marketing movement for more effective tobacco control measures including interactive social marketing campaigns and requiring plain packaging of tobacco products.
Impact on the Australian Quitline of new graphic cigarette pack warnings including the Quitline number: Figure 1
Authors: Miller C L , Hill D J , Quester P G , Hiller J E
Published: February 2009

Background:

In March 2006, Australia introduced graphic pictorial warnings on cigarette packets. For the first time, packs include the Quitline number.

Objective:

To measure the combined effect of graphic cigarette pack warnings and printing the Quitline number on packs on calls to the Australian Quitline service.

Methods:

Calls to the Australian Quitline were monitored over 4 years, 2 years before and after the new packets were introduced.

Results:

There were twice as many calls to the Quitline in 2006 (the year of introduction), as there were in each of the preceding 2 years. The observed increase in calls exceeds that explained by the accompanying television advertising alone. While call volume tapered back in 2007, it remained at a level higher than before the introduction of new packets. No change was observed in the proportion of first time callers.

Conclusion:

Introducing graphic cigarette packet warnings and the Quitline number on cigarette packets boosts demand for Quitline services, with likely flow on effects to cessation.
Education
Authors: Pietrobon Ricardo , Shah Jatin , Rajgor Dimple
Published: February 2009

Certificate Course in Outcomes Research From Data to Publication.
Ghrelin inhibits skeletal muscle protein breakdown in rats with thermal injury through normalizing elevated expression of E3 ubiquitin ligases MuRF1 and MAFbx
Authors: Balasubramaniam Ambikaipakan , Joshi Rashika , Su Chunhua , Friend Lou Ann , Sheriff Sulaiman , Kagan Richard J. , James J. Howard
Published: February 2009

We previously determined that ghrelin synthesis was downregulated after burn injury and that exogenous ghrelin retained its ability both to stimulate food intake and to restore plasma growth hormone levels in burned rats. These observations and the finding that anabolic hormones can attenuate skeletal muscle catabolism led us to investigate whether ghrelin could attenuate burn-induced skeletal muscle protein breakdown in rats. These studies were performed in young rats (50–60 g) 24 h after ∼30% total body surface area burn injury. Burn injury increased total and myofibrillar protein breakdown in extensor digitorum longus (EDL) muscles assessed by in vitro tyrosine and 3-methyl-histidine release, respectively. Continuous 24-h administration of ghrelin (0.2 mg·kg−1·h−1) significantly inhibited both total and myofibrillar protein breakdown in burned rats. Ghrelin significantly attenuated burn-induced changes in mRNA expression of IGFBP-1 and IGFBP-3 in liver. In EDL, ghrelin attenuated the increases in mRNA expression of the binding proteins, but had no significant effect on reduced expression of IGF-I. Ghrelin markedly reduced the elevated mRNA expression of TNF-α and IL-6 in EDL muscle that occurred after burn. Moreover, ghrelin normalized plasma glucocorticoid levels, which were elevated after burn. Expression of the muscle-specific ubiquitin-ligating enzyme (E3) ubiquitin ligases MuRF1 and MAFbx were markedly elevated in both EDL and gastrocnemius and were normalized by ghrelin. These results suggest that ghrelin is a powerful anticatabolic compound that reduces skeletal muscle protein breakdown through attenuating multiple burn-induced abnormalities.
Adiponectin is required to mediate rimonabant-induced improvement of insulin sensitivity but not body weight loss in diet-induced obese mice
Authors: Migrenne Stéphanie , Lacombe Amélie , Lefèvre Anne-Laure , Pruniaux Marie-Pierre , Guillot Etienne , Galzin Anne-Marie , Magnan Christophe
Published: February 2009

The increase in adiponectin levels in obese patients with untreated dyslipidemia and its mRNA expression in adipose tissue of obese animals are one of the most interesting consequences of rimonabant treatment. Thus, part of rimonabant's metabolic effects could be related to an enhancement of adiponectin secretion and its consequence on the modulation of insulin action, as well as energy homeostasis. The present study investigated the effects of rimonabant in adiponectin knockout mice (Ad−/−) exposed to diet-induced obesity conditions. Six-week-old Ad−/− male mice and their wild-type littermate controls (Ad+/+) were fed a high-fat diet for 7 mo. During the last month, animals were administered daily either with vehicle or rimonabant by mouth (10 mg/kg). High-fat feeding induced weight gain by about 130% in both wild-type and Ad−/− mice. Obesity was associated with hyperinsulinemia and insulin resistance. Treatment with rimonabant led to a significant and similar decrease in body weight in both Ad+/+ and Ad−/− mice compared with vehicle-treated animals. In addition, rimonabant significantly improved insulin sensitivity in Ad+/+ mice compared with Ad+/+ vehicle-treated mice by decreasing hepatic glucose production and increasing glucose utilization index in both visceral and subcutaneous adipose tissue. In contrast, rimonabant failed to improve insulin sensitivity in Ad−/− mice, despite the loss in body weight. Rimonabant's effect on body weight appeared independent of the adiponectin pathway, whereas adiponectin seems required to mediate rimonabant-induced improvement of insulin sensitivity in rodents.
Effects of varying combinations of intraduodenal lipid and carbohydrate on antropyloroduodenal motility, hormone release, and appetite in healthy males
Authors: Seimon Radhika V. , Feltrin Kate L. , Meyer James H. , Brennan Ixchel M. , Wishart Judith M. , Horowitz Michael , Feinle-Bisset Christine
Published: February 2009

Intraduodenal infusions of both lipid and glucose modulate antropyloroduodenal motility and stimulate plasma CCK, with lipid being more potent than glucose. Both stimulate glucagon-like peptide-1, but only lipid stimulates peptide YY (PYY), while only glucose raises blood glucose and stimulates insulin. When administered in combination, lipid and carbohydrate may, thus, have additive effects on energy intake. However, elevated blood glucose levels do not suppress energy intake, and the effect of insulin is controversial. We hypothesized that increasing the ratio of maltodextrin, a complex carbohydrate, relative to lipid would be associated with a reduction in effects on antropyloroduodenal pressures, gut hormones, appetite, and energy intake, when compared with lipid alone. Ten healthy males were studied on three occasions in double-blind, randomized order. Antropyloroduodenal pressures, plasma CCK, PYY and insulin, blood glucose, and appetite were measured during 90-min intraduodenal infusions of 1) 3 kcal/min lipid (L3), 2) 2 kcal/min lipid and 1 kcal/min maltodextrin (L2/CHO1), or 3) 1 kcal/min lipid and 2 kcal/min maltodextrin (L1/CHO2). Energy intake at a buffet lunch consumed immediately after the infusion was quantified. Reducing the lipid (thus, increasing the carbohydrate) content of the infusion was associated with reduced stimulation of basal pyloric pressures ( r = 0.76, P < 0.01), plasma CCK ( r = 0.66, P < 0.01), and PYY ( r = 0.98, P < 0.001), and reduced suppression of antral ( r = −0.64, P < 0.05) and duodenal ( r = −0.69, P < 0.05) pressure waves, desire-to-eat ( r = −0.8, P < 0.001), and energy intake ( r = 0.74, P < 0.01), with no differences in phasic (isolated) pyloric pressures. In conclusion, in healthy males, intraduodenal lipid is a more potent modulator of gut function, associated with greater suppression of energy intake, when compared with isocaloric combinations of lipid and maltodextrin.
Integration of cerebrovascular CO2reactivity and chemoreflex control of breathing: mechanisms of regulation, measurement, and interpretation
Authors: Ainslie Philip N. , Duffin James
Published: February 2009

Cerebral blood flow (CBF) and its distribution are highly sensitive to changes in the partial pressure of arterial CO2(PaCO2). This physiological response, termed cerebrovascular CO2reactivity, is a vital homeostatic function that helps regulate and maintain central pH and, therefore, affects the respiratory central chemoreceptor stimulus. CBF increases with hypercapnia to wash out CO2from brain tissue, thereby attenuating the rise in central Pco2, whereas hypocapnia causes cerebral vasoconstriction, which reduces CBF and attenuates the fall of brain tissue Pco2. Cerebrovascular reactivity and ventilatory response to PaCO2are therefore tightly linked, so that the regulation of CBF has an important role in stabilizing breathing during fluctuating levels of chemical stimuli. Indeed, recent reports indicate that cerebrovascular responsiveness to CO2, primarily via its effects at the level of the central chemoreceptors, is an important determinant of eupneic and hypercapnic ventilatory responsiveness in otherwise healthy humans during wakefulness, sleep, and exercise and at high altitude. In particular, reductions in cerebrovascular responsiveness to CO2that provoke an increase in the gain of the chemoreflex control of breathing may underpin breathing instability during central sleep apnea in patients with congestive heart failure and on ascent to high altitude. In this review, we summarize the major factors that regulate CBF to emphasize the integrated mechanisms, in addition to PaCO2, that control CBF. We discuss in detail the assessment and interpretation of cerebrovascular reactivity to CO2. Next, we provide a detailed update on the integration of the role of cerebrovascular CO2reactivity and CBF in regulation of chemoreflex control of breathing in health and disease. Finally, we describe the use of a newly developed steady-state modeling approach to examine the effects of changes in CBF on the chemoreflex control of breathing and suggest avenues for future research.