bluuebunny/crossref_metadata_2025 huggingface dataset:
Roles for NK Cells and an NK Cell-Independent Source of Intestinal Gamma Interferon for Innate Immunity toCryptosporidium parvumInfection
Authors: Barakat Farah M. , McDonald Vincent , Di Santo James P. , Korbel Daniel S.
Published: August 2009

A gamma interferon (IFN-γ)-dependent innate immune response operates against the intestinal parasiteCryptosporidium parvumin T- and B-cell-deficient SCID mice. Although NK cells are a major source of IFN-γ in innate immunity, their protective role againstC. parvumhas been unclear. The role of NK cells in innate immunity was investigated using Rag2−/−mice, which lack T and B cells, and Rag2−/−γc−/−mice, which, in addition, lack NK cells. Adult mice of both knockout lines developed progressive chronic infections; however, on most days the level of oocyst excretion was higher in Rag2−/−γc−/−mice and these animals developed morbidity and died, whereas within the same period the Rag2−/−mice appeared healthy. Neonatal mice of both mouse lines survived a rapid onset of infection that reached a higher intensity in Rag2−/−γc−/−mice. Significantly, similar levels of intestinal IFN-γ mRNA were expressed in Rag2−/−and Rag2−/−γc−/−mice. Also, infections in each mouse line were exacerbated by treatment with anti-IFN-γ neutralizing antibodies. These results support a protective role for NK cells and IFN-γ in innate immunity againstC. parvum. In addition, the study implies that an intestinal cell type other than NK cells may be an important source of IFN-γ during infection and that NK cells may have an IFN-γ-independent protective role.
Microbial Quorum-Sensing Molecules Induce Acrosome Loss and Cell Death in Human Spermatozoa
Authors: Rennemeier Claudia , Frambach Torsten , Hennicke Florian , Dietl Johannes , Staib Peter
Published: August 2009

Infertility in men and women is frequently associated with genital contamination by various commensal or uropathogenic microbes. Since many microorganisms are known to release quorum-sensing signals in substantial amounts, we raised the question whether such molecules can directly affect human spermatozoa. Here we show that farnesol and 3-oxododecanoyl-
l
-homoserine lactone, employed by the opportunistic pathogenic yeast
Candida albicans
and the gram-negative bacterium
Pseudomonas aeruginosa
, respectively, induce multiple damage in spermatozoa. A reduction in the motility of spermatozoa coincided in a dose-dependent manner with apoptosis and necrosis at concentrations which were nondeleterious for dendritic cell-like immune cells. Moreover, sublethal doses of both signaling molecules induced premature loss of the acrosome, a cap-like structure of the sperm head which is essential for fertilization. Addressing their mechanism of action, we found that the bacterial molecule, but not the fungal molecule, actively induced the acrosome reaction via a calcium-dependent mechanism. This work uncovers a new facet in the interaction of microorganisms with human gametes and suggests a putative link between microbial communication systems and host infertility.
Ehrlichia chaffeensis
Infections in
Drosophila melanogaster
Authors: Luce-Fedrow Alison , Von Ohlen Tonia , Chapes Stephen K.
Published: August 2009

Ehrlichia chaffeensis
is an obligate, intracellular bacterium, transmitted by the tick
Amblyomma americanum
, and is the causative agent of human monocytic ehrlichiosis infections. We previously demonstrated that
E. chaffeensis
is capable of growing in
Drosophila
S2 cells. Therefore, we tested the hypothesis that
E. chaffeensis
can infect adult
Drosophila melanogaster
. Adult
Drosophila
organisms were experimentally challenged with intra-abdominal injections of bacteria.
Ehrlichia
-infected flies showed decreased survival compared to wild-type flies, and bacteria isolated from flies could reinfect mammalian macrophages.
Ehrlichia
infections activated both the cellular and humoral immune responses in the fly. Hemocytes phagocytosed bacteria after injection, and antimicrobial peptide pathways were induced following infection. Increased pathogenicity in flies carrying mutations in genes in both the Toll and Imd pathways suggests that both immune defense pathways participate in host defense. Induction of
Drosophila
cellular and humoral responses and the in vivo replication of
E. chaffeensis
suggests that
D. melanogaster
is a suitable host for
E. chaffeensis
. In the future, it will be a useful tool to unlock some of the in vivo mysteries of this arthropod-borne bacterium.
The NS1 Protein of the 1918 Pandemic Influenza Virus Blocks Host Interferon and Lipid Metabolism Pathways
Authors: Billharz Rosalind , Zeng Hui , Proll Sean C. , Korth Marcus J. , Lederer Sharon , Albrecht Randy , Goodman Alan G. , Rosenzweig Elizabeth , Tumpey Terrence M. , García-Sastre Adolfo , Katze Michael G.
Published: August 2009

The “Spanish influenza” of 1918 claimed an unprecedented number of lives, yet the determinants of virulence for this virus are still not fully understood. Here, we used functional genomics and an in vitro human lung epithelial cell infection model to define the global host transcriptional response to the eight-gene 1918 virus. To better understand the role of the 1918 virus NS1 gene, we also evaluated the host response to a reassortant 1918 virus containing the NS1 gene from A/Texas/36/91 (a seasonal isolate of human influenza virus), as well as the host response to a reassortant of A/Texas/36/91 containing the 1918 NS1 gene. Genomic analyses revealed that the 1918 virus blocked the transcription of multiple interferon-stimulated genes and also downregulated a network of genes associated with lipid metabolism. In contrast, the expression of genes encoding chemokines and cytokines, which serve to attract infiltrating immune cells, was upregulated. Viruses containing the NS1 gene from A/Texas/36/91 induced a significant increase in type I interferon signaling but did not repress lipid metabolism. The 1918 NS1 gene may therefore have contributed to the virulence of the 1918 pandemic virus by disrupting the innate immune response, inducing hypercytokinemia, and by blocking the transcription of certain lipid-based proinflammatory mediators that function as part of the host antiviral response.
Host Genetic Variation Affects Resistance to Infection with a Highly Pathogenic H5N1 Influenza A Virus in Mice
Authors: Boon Adrianus C. M. , deBeauchamp Jennifer , Hollmann Anna , Luke Jennifer , Kotb Malak , Rowe Sarah , Finkelstein David , Neale Geoffrey , Lu Lu , Williams Robert W. , Webby Richard J.
Published: August 2009

Despite the prevalence of H5N1 influenza viruses in global avian populations, comparatively few cases have been diagnosed in humans. Although viral factors almost certainly play a role in limiting human infection and disease, host genetics most likely contribute substantially. To model host factors in the context of influenza virus infection, we determined the lethal dose of a highly pathogenic H5N1 virus (A/Hong Kong/213/03) in C57BL/6J and DBA/2J mice and identified genetic elements associated with survival after infection. The lethal dose in these hosts varied by 4 logs and was associated with differences in replication kinetics and increased production of proinflammatory cytokines CCL2 and tumor necrosis factor alpha in susceptible DBA/2J mice. Gene mapping with recombinant inbred BXD strains revealed five loci orQivr(quantitative trait loci forinfluenzavirusresistance) located on chromosomes 2, 7, 11, 15, and 17 associated with resistance to H5N1 virus. In conjunction with gene expression profiling, we identified a number of candidate susceptibility genes. One of the validated genes, the hemolytic complement gene, affected virus titer 7 days after infection. We conclude that H5N1 influenza virus-induced pathology is affected by a complex and multigenic host component.
Human Immunodeficiency Virus Type 1 Protease-Correlated Cleavage Site Mutations Enhance Inhibitor Resistance
Authors: Kolli Madhavi , Stawiski Eric , Chappey Colombe , Schiffer Celia A.
Published: August 2009

Drug resistance is an important cause of antiretroviral therapy failure in human immunodeficiency virus (HIV)-infected patients. Mutations in the protease render the virus resistant to protease inhibitors (PIs). Gag cleavage sites also mutate, sometimes correlating with resistance mutations in the protease, but their contribution to resistance has not been systematically analyzed. The present study examines mutations in Gag cleavage sites that associate with protease mutations and the impact of these associations on drug susceptibilities. Significant associations were observed between mutations in the nucleocapsid-p1 (NC-p1) and p1-p6 cleavage sites and various PI resistance-associated mutations in the protease. Several patterns were frequently observed, including mutations in the NC-p1 cleavage site in combination with I50L, V82A, and I84V within the protease and mutations within the p1-p6 cleavage site in combination with D30N, I50V, and I84V within the protease. For most patterns, viruses with mutations both in the protease and in either cleavage site were significantly less susceptible to specific PIs than viruses with mutations in the protease alone. Altered PI resistance in HIV-1 was found to be associated with the presence of Gag cleavage site mutations. These studies suggest that associated cleavage site mutations may contribute to PI susceptibility in highly specific ways depending on the particular combinations of mutations and inhibitors. Thus, cleavage site mutations should be considered when assessing the level of PI resistance.
Preinfection Human Immunodeficiency Virus (HIV)-Specific Cytotoxic T Lymphocytes Failed To Prevent HIV Type 1 Infection from Strains Genetically Unrelated to Viruses in Long-Term Exposed Partners
Authors: Liu Yi , Woodward Amanda , Zhu Haiying , Andrus Thomas , McNevin John , Lee Jean , Mullins James I. , Corey Lawrence , McElrath M. Juliana , Zhu Tuofu
Published: August 2009

Understanding the mechanisms underlying potential altered susceptibility to human immunodeficiency virus type 1 (HIV-1) infection in highly exposed seronegative (ES) individuals and the later clinical consequences of breakthrough infection can provide insight into strategies to control HIV-1 with an effective vaccine. From our Seattle ES cohort, we identified one individual (LSC63) who seroconverted after over 2 years of repeated unprotected sexual contact with his HIV-1-infected partner (P63) and other sexual partners of unknown HIV-1 serostatus. The HIV-1 variants infecting LSC63 were genetically unrelated to those sequenced from P63. This may not be surprising, since viral load measurements in P63 were repeatedly below 50 copies/ml, making him an unlikely transmitter. However, broad HIV-1-specific cytotoxic T-lymphocyte (CTL) responses were detected in LSC63 before seroconversion. Compared to those detected after seroconversion, these responses were of lower magnitude and half of them targeted different regions of the viral proteome. Strong HLA-B27-restricted CTLs, which have been associated with disease control, were detected in LSC63 after but not before seroconversion. Furthermore, for the majority of the protein-coding regions of the HIV-1 variants in LSC63 (except
gp41
,
nef
, and the 3′ half of
pol
), the genetic distances between the infecting viruses and the viruses to which he was exposed through P63 (termed the exposed virus) were comparable to the distances between random subtype B HIV-1 sequences and the exposed viruses. These results suggest that broad preinfection immune responses were not able to prevent the acquisition of HIV-1 infection in LSC63, even though the infecting viruses were not particularly distant from the viruses that may have elicited these responses.
Human Immunodeficiency Virus Type 1 Mediates Global Disruption of Innate Antiviral Signaling and Immune Defenses within Infected Cells
Authors: Doehle Brian P. , Hladik Florian , McNevin John P. , McElrath M. Juliana , Gale Michael
Published: August 2009

Interferon regulatory factor 3 (IRF-3) is essential for innate intracellular immune defenses that limit virus replication, but these defenses fail to suppress human immunodeficiency virus (HIV) infection, which can ultimately associate with opportunistic coinfections and the progression to AIDS. Here, we examined antiviral defenses in CD4+cells during virus infection and coinfection, revealing that HIV type 1 (HIV-1) directs a global disruption of innate immune signaling and supports a coinfection model through suppression of IRF-3. T cells responded to paramyxovirus infection to activate IRF-3 and interferon-stimulated gene expression, but they failed to mount a response against HIV-1. The lack of response associated with a marked depletion of IRF-3 but not IRF-7 in HIV-1-infected cells, which supported robust viral replication, whereas ectopic expression of active IRF-3 suppressed HIV-1 infection. IRF-3 depletion was dependent on a productive HIV-1 replication cycle and caused the specific disruption of Toll-like receptor and RIG-I-like receptor innate immune signaling that rendered cells permissive to secondary virus infection. IRF-3 levels were reduced in vivo within CD4+T cells from patients with acute HIV-1 infection but not from long-term nonprogressors. Our results indicate that viral suppression of IRF-3 promotes HIV-1 infection by disrupting IRF-3-dependent signaling pathways and innate antiviral defenses of the host cell. IRF-3 may direct an innate antiviral response that regulates HIV-1 replication and viral set point while governing susceptibility to opportunistic virus coinfections.
Drastic Reduction in the Production of Subviral Particles Does Not Impair Hepatitis B Virus Virion Secretion
Authors: Garcia Tamako , Li Jisu , Sureau Camille , Ito Kiyoaki , Qin Yanli , Wands Jack , Tong Shuping
Published: August 2009

Hepatitis B virus (HBV) contains three coterminal envelope proteins on the virion surface: large (L), middle (M), and small (S). The M and S proteins are also secreted as empty “subviral particles,” which exceed virions by at least 1,000-fold. The S protein serves as the morphogenic factor for both types of particles, while the L protein is required only for virion formation. We found that cotransfecting replication constructs with a small dose of the expression construct for the missing L, M, and S proteins reconstituted efficient virion secretion but only 5 to 10% of subviral particles. The L protein inhibited secretion of subviral particles in a dose-dependent manner, whereas a too-high or too-low L/S protein ratio inhibited virion secretion. Consistent with the results of cotransfection experiments, a point mutation at the −3 position of the S gene AUG codon reduced HBsAg secretion by 60 to 70% but maintained efficient virion secretion. Surprisingly, ablating M protein expression reduced virion secretion but markedly increased the maturity of virion-associated genomes, which could be reversed by providing
in trans
both L and M proteins but not just M protein. M protein stability was dependent on the coexpression of S protein. Our findings suggest that efficient HBV virion secretion could be maintained despite drastic reduction in subviral particle production, which supports the recent demonstration of separate secretion pathways adopted by the two types of particles. The M protein appears to facilitate core particle envelopment, thus shortening the window of plus strand DNA elongation.
Two-Step Conformational Changes in a Coronavirus Envelope Glycoprotein Mediated by Receptor Binding and Proteolysis
Authors: Matsuyama Shutoku , Taguchi Fumihiro
Published: August 2009

The coronaviruses mouse hepatitis virus type 2 (MHV-2) and severe acute respiratory syndrome coronavirus (SARS-CoV) utilize proteases to enter host cells. Upon receptor binding, the spike (S) proteins of both viruses are activated for membrane fusion by proteases, such as trypsin, present in the environment, facilitating virus entry from the cell surface. In contrast, in the absence of extracellular proteases, these viruses can enter cells via an endosomal pathway and utilize endosomal cathepsins for S protein activation. We demonstrate that the MHV-2 S protein uses multistep conformational changes for membrane fusion. After interaction with a soluble form of the MHV receptor (CEACAM1a), the metastable form of S protein is converted to a stable trimer, as revealed by mildly denaturing sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Liposome-binding assays indicate that the receptor-bound virions are associated with the target membrane through hydrophobic interactions. The exposure of receptor-bound S protein to trypsin or cathepsin L (CPL) induces the formation of six-helix bundles (6HB), the final conformation. This trypsin- or CPL-mediated conversion to 6HB can be blocked by a heptad repeat peptide known to block the formation of 6HB. Although trypsin treatment enabled receptor-bound MHV-2 to enter from the cell surface, CPL failed to do so. Interestingly, consecutive treatment with CPL and then chlorpromazine enabled a portion of the virus to enter from cell surface. These results suggest that trypsin suffices for the induction of membrane fusion of receptor-primed S protein, but an additional unidentified cellular factor is required to trigger membrane fusion by CPL.
Peptides That Mimic the Amino-Terminal End of the Rabies Virus Phosphoprotein Have Antiviral Activity
Authors: Castel Guillaume , Chtéoui Mohamed , Caignard Grégory , Préhaud Christophe , Méhouas Stéphanie , Réal Eléonore , Jallet Corinne , Jacob Yves , Ruigrok Rob W. H. , Tordo Noël
Published: August 2009

We wanted to develop a therapeutic approach against rabies disease by targeting the lyssavirus transcription/replication complex. Because this complex (nucleoprotein N-RNA template processed by the L polymerase and its cofactor, the phosphoprotein P) is similar to that of other negative-strand RNA viruses, we aimed to design broad-spectrum antiviral drugs that could be used as a complement to postexposure vaccination and immunotherapy. Recent progress in understanding the structure/function of the rabies virus P, N, and L proteins predicts that the amino-terminal end of P is an excellent target for destabilizing the replication complex because it interacts with both L (for positioning onto the N-RNA template) and N (for keeping N soluble, as needed for viral RNA encapsidation). Thus, peptides mimicking various lengths of the amino-terminal end of P have been evaluated, as follows: (i) for binding properties to the N-P-L partners by the two-hybrid method; (ii) for their capacity to inhibit the transcription/replication of a rabies virus minigenome encoding luciferase in BHK-21-T7 cells; and (iii) for their capacity to inhibit rabies virus infection of BHK-21-T7 cells and of two derivatives of the neuronal SK-N-SH cell line. Peptides P60 and P57 (the first 60 and first 57 NH
2
residues of P, respectively) exhibited a rapid, strong, and long-lasting inhibitory potential on luciferase expression (>95% from 24 h to 55 h). P42 was less efficient in its inhibition level (75% for 18 to 30 h) and duration (40% after 48 h). The most promising peptides were synthesized in tandem with the Tat sequence, allowing cell penetration. Their inhibitory effects were observed on BHK-21-T7 cells infected with rabies virus and Lagos bat virus but not with vesicular stomatitis virus. In neuronal cells, a significant inhibition of both nucleocapsid inclusions and rabies virus release was observed.
Identification of a Novel Astrovirus (Astrovirus VA1) Associated with an Outbreak of Acute Gastroenteritis
Authors: Finkbeiner Stacy R. , Li Yan , Ruone Susan , Conrardy Christina , Gregoricus Nicole , Toney Denise , Virgin Herbert W. , Anderson Larry J. , Vinjé Jan , Wang David , Tong Suxiang
Published: August 2009

The etiology of a large proportion of gastrointestinal illness is unknown. In this study, random Sanger sequencing and pyrosequencing approaches were used to analyze fecal specimens from a gastroenteritis outbreak of unknown etiology in a child care center. Multiple sequences with limited identity to known astroviruses were identified. Assembly of the sequences and subsequent reverse transcription-PCR (RT-PCR) and rapid amplification of cDNA ends generated a complete genome of 6,586 nucleotides. Phylogenetic analysis demonstrated that this virus, named astrovirus VA1 (AstV-VA1), is highly divergent from all previously described astroviruses. Based on RT-PCR, specimens from multiple patients in this outbreak were unequivocally positive for Ast-VA1.
Respiratory Syncytial Virus Infection Induces a Reactive Oxygen Species-MSK1-Phospho-Ser-276 RelA Pathway Required for Cytokine Expression
Authors: Jamaluddin Mohammad , Tian Bing , Boldogh Istvan , Garofalo Roberto P. , Brasier Allan R.
Published: August 2009

Respiratory syncytial virus (RSV) is a human pathogen that induces airway inflammation, at least in part, by modulating gene expression programs in airway epithelial cells. The presence of RSV replication is detected by the intracellular retinoic acid-inducible gene I (RIG-I) RNA helicase that forms a productive signaling complex with the mitochondrion-anchored MAVS protein, resulting in nuclear translocation of the NF-κB transcription factor. Although nuclear translocation is a prerequisite for activation of the innate inflammatory response, recent studies show that separate pathways governing RelA activation are also required for target gene expression. In this study, we examine the mechanism of RelA phosphorylation and its requirement for RSV-induced gene expression. RSV infection produced a time-dependent RelA phosphorylation on serine (Ser) residues Ser-276 and Ser-536 in parallel with enhanced reactive oxygen species (ROS) stress. Inhibition of RSV-induced ROS inhibited formation of phospho-Ser-276 RelA without affecting phospho-Ser-536 RelA formation. RSV potently induced activation of cytoplasmic mitogen- and stress-related kinase 1 (MSK1) in an ROS-dependent manner. Inhibition of MSK1 using H89 and small interfering RNA knockdown both reduced RSV-induced phospho-Ser-276 RelA formation and expression of a subset of NF-κB-dependent genes. Direct examination of the role of phospho-Ser-276 in target gene expression by expression of a RelA Ser-276-to-Ala site mutation in RelA
−/−
mouse embryonic fibroblasts showed that the mutation was unable to mediate RSV-induced NF-κB-dependent gene expression. We conclude that RSV induces RelA activation in the innate inflammatory response via a pathway separate from that controlling RelA cytoplasmic release, mediated by ROS signaling to cytoplasmic MSK1 activation and RelA Ser-276 phosphorylation.
Baculovirus DNA Replication-Specific Expression Factors Trigger Apoptosis and Shutoff of Host Protein Synthesis during Infection
Authors: Schultz Kimberly L. W. , Friesen Paul D.
Published: August 2009

Apoptosis is an important antivirus defense. To define the poorly understood pathways by which invertebrates respond to viruses by inducing apoptosis, we have identified replication events that trigger apoptosis in baculovirus-infected cells. We used RNA silencing to ablate factors required for multiplication of
Autographa californica
multicapsid nucleopolyhedrovirus (Ac
M
NPV). Transfection with double-stranded RNA (dsRNA) complementary to the Ac
M
NPV late expression factors (
lef
s) that are designated as replicative
lef
s (
lef-1
,
lef-2
,
lef-3
,
lef-11
,
p143
,
dnapol
, and
ie-1
/
ie-0
) blocked virus DNA synthesis and late gene expression in permissive
Spodoptera frugiperda
cells. dsRNAs specific to designated nonreplicative
lef
s (
lef-8
,
lef-9
,
p47
, and
pp31
) blocked late gene expression without affecting virus DNA replication. Thus, both classes of
lef
s functioned during infection as defined. Silencing the replicative
lef
s prevented Ac
M
NPV-induced apoptosis of
Spodoptera
cells, whereas silencing the nonreplicative
lef
s did not. Thus, the activity of replicative
lef
s or virus DNA replication is sufficient to trigger apoptosis. Confirming this conclusion, Ac
M
NPV-induced apoptosis was suppressed by silencing the replicative
lef
s in cells from a divergent species,
Drosophila melanogaster
. Silencing replicative but not nonreplicative
lef
s also abrogated Ac
M
NPV-induced shutdown of host protein synthesis, suggesting that virus DNA replication triggers inhibition of host biosynthetic processes and that apoptosis and translational arrest are linked. Our findings suggest that baculovirus DNA replication triggers a host cell response similar to the DNA damage response in vertebrates, which causes translational arrest and apoptosis. Pathways for detecting virus invasion and triggering apoptosis may therefore be conserved between insects and mammals.
Partial Inhibition of Human Immunodeficiency Virus Replication by Type I Interferons: Impact of Cell-to-Cell Viral Transfer
Authors: Vendrame Daniela , Sourisseau Marion , Perrin Virginie , Schwartz Olivier , Mammano Fabrizio
Published: August 2009

Type I interferons (IFN) inhibit several steps of the human immunodeficiency virus type 1 (HIV) replication cycle. Some HIV proteins, like Vif and Vpu, directly counteract IFN-induced restriction factors. Other mechanisms are expected to modulate the extent of IFN inhibition. Here, we studied the impact of IFN on various aspects of HIV replication in primary T lymphocytes. We confirm the potent effect of IFN on Gag p24 production in supernatants. Interestingly, IFN had a more limited effect on HIV spread, measured as the appearance of Gag-expressing cells. Primary isolates displayed similar differences in the inhibition of p24 release and virus spread. Virus emergence was the consequence of suboptimal inhibition of HIV replication and was not due to the selection of resistant variants. Cell-to-cell HIV transfer, a potent means of virus replication, was less sensitive to IFN than infection by cell-free virions. These results suggest that IFN are less active in cell cultures than initially thought. They help explain the incomplete protection by naturally secreted IFN during HIV infection and the unsatisfactory outcome of IFN treatment in HIV-infected patients.
Lentiviral Vector-Based Prime/Boost Vaccination against AIDS: Pilot Study Shows Protection against Simian Immunodeficiency Virus SIVmac251 Challenge in Macaques
Authors: Beignon Anne-Sophie , Mollier Karine , Liard Christelle , Coutant Frédéric , Munier Sandie , Rivière Julie , Souque Philippe , Charneau Pierre
Published: August 2009

AIDS vaccination has a pressing need for more potent vaccination vectors capable of eliciting strong, diversified, and long-lasting cellular immune responses against human immunodeficiency virus (HIV). Lentiviral vectors have demonstrated efficiency not only as gene delivery vehicles for gene therapy applications but also as vaccination tools. This is likely due to their ability to transduce nondividing cells, including dendritic cells, enabling sustained endogenous antigen presentation and thus the induction of high proportions of specific cytotoxic T cells and long-lasting memory T cells. We show in a first proof-of-concept pilot study that a prime/boost vaccination strategy using lentiviral vectors pseudotyped with a glycoprotein G from two non-cross-reactive vesicular stomatitis virus serotypes elicited robust and broad cellular immune responses against the vector-encoded antigen, simian immunodeficiency virus (SIV) GAG, in cynomolgus macaques. Vaccination conferred strong protection against a massive intrarectal challenge with SIVmac251, as evidenced both by the reduction of viremia at the peak of acute infection (a mean of over 2 log10fold reduction) and by the full preservation of the CD28+CD95+memory CD4+T cells during the acute phase, a strong correlate of protection against pathogenesis. Although vaccinees continued to display lower viremia than control macaques during the early chronic phase, these differences were not statistically significant by day 50 postchallenge. A not-optimized SIV GAG antigen was chosen to show the strong potential of the lentiviral vector system for vaccination. Given that a stronger protection can be anticipated from a modern HIV-1 antigen design, gene transfer vectors derived from HIV-1 appear as promising candidates for vaccination against HIV-1 infection.
Low pH-Triggered Beta-Propeller Switch of the Low-Density Lipoprotein Receptor Assists Rhinovirus Infection
Authors: Konecsni Tuende , Berka Ursula , Pickl-Herk Angela , Bilek Gerhard , Khan Abdul Ghafoor , Gajdzig Leszek , Fuchs Renate , Blaas Dieter
Published: August 2009

Minor group human rhinoviruses (HRVs) bind three members of the low-density lipoprotein receptor (LDLR) family: LDLR proper, very-LDLR (VLDLR) and LDLR-related protein (LRP). Whereas ICAM-1, the receptor of major group HRVs actively contributes to viral uncoating, LDLRs are rather considered passive vehicles for cargo delivery to the low-pH environment of endosomes. Since the Tyr-Trp-Thr-Asp β-propeller domain of LDLR has been shown to be involved in the dissociation of bound LDL via intramolecular competition at low pH, we studied whether it also plays a role in HRV infection. Human cell lines deficient in LDLR family proteins are not available. Therefore, we used CHO
-ldla7
cells that lack endogenous LDLR. These were stably transfected to express either wild-type (wt) human LDLR or a mutant with a deletion of the β-propeller. When HRV2 was attached to the propeller-negative LDLR, a lower pH was required for conversion to subviral particles than when attached to wt LDLR. This indicates that high-avidity receptor binding maintains the virus in its native conformation. HRV2 internalization directed the mutant LDLR but not wt LDLR to lysosomes, resulting in reduced plasma membrane expression of propeller-negative LDLR. Infection assays using a CHO-adapted HRV2 variant showed a delay in intracellular viral conversion and de novo viral synthesis in cells expressing the truncated LDLR. Our data indicate that the β-propeller attenuates the virus-stabilizing effect of LDLR binding and thereby facilitates RNA release from endosomes, resulting in the enhancement of infection. This is a nice example of a virus exploiting high-avidity multimodule receptor binding with an intrinsic release mechanism.
Novel Avian Bornavirus in a Nonpsittacine Species (Canary;
Serinus canaria
) with Enteric Ganglioneuritis and Encephalitis
Authors: Weissenböck Herbert , Sekulin Karin , Bakonyi Tamás , Högler Sandra , Nowotny Norbert
Published: August 2009

A canary bird (
Serinus canaria
) died with nonsuppurative ganglioneuritis of the proventriculus and gizzard and encephalitis, lesions comparable to proventricular dilatation disease (PDD) of psittacine birds. Recently, several genotypes of a novel avian bornavirus have been linked to PDD. In the canary, bornaviral antigen was detected by immunohistochemistry in both neural and extraneural tissues. The widespread viral dissemination was confirmed by reverse transcription-PCR. Sequence analysis revealed a unique genotype of avian bornavirus. This observation suggests that bornaviruses are natural pathogens of several avian species and that the family
Bornaviridae
comprises more viral genotypes (or viral species) than previously assumed.
Relationship of ventricular and atrial dilatation to valvular function in endurance athletes
Authors: Prakken N H , Velthuis B K , Bosker A C , Mosterd A , Teske A J , Mali W P , Cramer M J
Published: August 2009

Objective

To establish cardiac magnetic resonance imaging (MRI) reference values for atrial adaptation to training in endurance athletes in comparison with matched non-athletes. In addition, to study the relationship of atrial size to ventricular and annular size and valvular function.

Design

Cross-sectional study.

Participants

180 healthy individuals aged 18–39 years (41% women): 60 elite endurance athletes (exercising > 18 h/week), 60 regular endurance athletes (9–18 h/ week), and 60 age and gender matched non-athletes (exercising ≤3 h/week) underwent cardiac MRI. Quantitative atrial dimensions and volumes, indexed for body surface area (BSA), were compared with ventricular and annular dimensions. Regurgitant fractions of all four valves and peak velocities of mitral and tricuspid valves were also assessed.

Results

BSA-corrected right and left atrial volumes and diameters were significantly larger for athletes compared with non-athletes (p<0.05–p<0.0005). Ventricular, annular and atrial ratios remained constant for all groups, suggesting balanced adaptation to exercise training. E/A ratios remained statistically unchanged in all groups. Regurgitant fractions of the four cardiac valves were all mild (≤15%) and not significantly different in athletes compared with non-athletes.

Conclusions

Atrial remodelling in endurance athletes may be regarded as a balanced physiological adaptation to exercise training with preservation of valvular function.
The pathology of Wilms' tumour (nephroblastoma): the International Society of Paediatric Oncology approach
Authors: Vujanić G M , Sandstedt B
Published: August 2009

In the International Society of Paediatric Oncology renal tumour trials, preoperative chemotherapy has been successfully applied with resulting reduction of tumour rupture and increased favourable stage distribution of nephroblastoma. Postoperative treatment includes chemotherapy and sometimes radiotherapy in a risk-adapted approach based on histological sub-classification and stage of the tumour. However, preoperative chemotherapy alters the tumour's histological features and distribution of subtypes, and makes staging more difficult. The paper highlights the most common practical diagnostic difficulties that a pathologist is faced with in dealing with pretreated nephroblastomas. It emphasises the importance of a systematic, step-by-step analysis based on adequately sampled material, in order to accurately sub-classify a nephroblastoma as a low, intermediate or high risk tumour and assign its genuine stage. Finally, it outlines the standard operating procedure for submission of renal tumours for rapid central pathology review which allows the treating oncologists to apply the optimal treatment protocol.
Curative cerebrovascular reconstruction with the Pipeline embolization device: the emergence of definitive endovascular therapy for intracranial aneurysms
Authors: Fiorella D , Lylyk P , Szikora I , Kelly M E , Albuquerque F C , McDougall C G , Nelson P K
Published: August 2009

Endovascular, endosaccular, coil embolization has emerged as an established therapy for both ruptured and unruptured cerebral aneurysms. However, many aneurysms are not cured using conventional endovascular techniques. Coil embolization often results in incomplete aneurysm occlusion or recanalization in the ensuing months after treatment. The Pipeline embolization device (PED; Chestnut Medical) represents a new generation endoluminal implant which is designed to treat aneurysms by reconstructing the diseased parent artery. Immediately after implantation, the PED functions to divert flow from the aneurysm, creating an environment conducive to thrombosis. With time, the PED is incorporated into the vessel wall as neointimal–endothelial overgrowth occurs along the construct. Ultimately, this process results in the durable complete exclusion of the aneurysm from the cerebrovasculature and a definitive endoluminal reconstruction of the diseased parent artery.
Infectious pseudoaneurysm of the internal carotid artery treated with a covered stent
Authors: Bulsara K R , Aruny J E , Muhs B
Published: August 2009

Rapidly expanding infectious pseudoaneurysms of the internal carotid artery can have deleterious consequences. A patient is reported who presented with such an aneurysm. The morphology of the aneurysm was not amenable to microsurgical treatment. The aneurysm was successfully treated with covered stents. This is only the third report of a patient with an infectious pseudoaneurysm in the internal carotid artery treated with a covered stent. At the 1 year follow-up visit, the patient continues to do well.
Prospective assessment of pain and functional status after vertebroplasty for treatment of vertebral compression fractures
Authors: Evans A J , Kip K E , Boutin S M
Published: August 2009

Background and purpose

There has been no prospective evaluation of vertebroplasty using a validated instrument. We describe the pain and functional status of 72 patients before and after vertebroplasty, as prospectively evaluated by the Vertebral Compression Fracture Pain and Functional Disability Questionnaire.

Methods

Of 161 consecutive patients, 72 consented to participate in the study and self-completed the questionnaire prior to undergoing vertebroplasty. Differences in pain and distress before and after vertebroplasty, and between the first and second follow-up intervals, were evaluated. Mean scores for each of 24 activities of daily living (ADLs) were plotted at the baseline and first and second follow-up intervals.

Results

The mean (SD) patient age was 74 (10) years; 80% were female. On the 0 (no pain) to 10 (pain as bad as it could be) visual analog pain scale, patients reported significantly more pain, on average, before undergoing percutaneous vertebroplasty (PV) than at the first follow-up interval (mean 5.8 vs 3.5, p<0.001). The reduction in reported pain following vertebroplasty persisted at the second follow-up on both the visual analog and adjectival pain scales. Among the 24 ADLs, between 25% and 69% of patients reported a mean improvement of at least 1 level on the 5-point ADL scale, and between 14% and 55% reported a mean improvement of at least two levels. The majority of the improvement in reported functional status following vertebroplasty was sustained at the second follow-up interval.

Conclusion

PV resulted in substantial, lasting reduction in pain and improvement in ability to perform ADLs.
Predicting acute ischemic stroke by measuring the degree of ocular gaze deviation (Prévost's sign) on CT: Figure 1
Authors: Lesley W S , Rangaswamy R , Smith K H , Watkins D M
Published: August 2009

Background and aim

Ocular gaze deviation (OGD) is a well known clinical observation (Prevost's sign) in patients with acute cerebral ischemic stroke. Although OGD has been observed on CT in acute stroke, no investigation has quantified the degree of OGD in acute stroke.

Material and methods

A blinded prospective comparison was performed of two groups of adult patients who underwent CT of the brain. Group 1 comprised patients with acute hemiplegia or hemiparesis due to middle cerebral artery ischemic stroke. Group 2 included ambulatory outpatients with a history of headache but no clinical neurologic signs or cerebral pathology on CT. The CT images were cropped to only show the orbital contents. A neuroradiologist, who was blinded to the clinical data, then measured the OGD for both groups. The OGD was quantified using the axial planes of the lenses relative to the nasal midline structures, and the bilateral OGD average was calculated. Both groups were also evaluated for conjugate or disconjugate gaze. Results were analyzed using Fisher's exact test.

Results

10 of 70 patients in group 1 and 15 of 46 patients in group 2 were eligible for analysis. The frequency of conjugate and disconjugate gaze was similar in the two groups (p = 0.596). An averaged OGD of >14° and an OGD >18° in either globe was predictive of the presence of acute stroke (p = 0.0166).

Conclusion

Measurement of OGD is useful in predicting the presence of acute ischemic stroke.
Results of cutting balloon angioplasty for carotid artery in-stent restenosis in six patients: description of the technique, long-term outcomes, and review of the literature
Authors: Heck D
Published: August 2009

Background/purpose

The optimal management of carotid artery in-stent restenosis is not well described. Reported here is experience with cutting balloon angioplasty in six patients with long-term follow-up.

Methods

A single-operator, prospective, elective, carotid artery stent registry (n = 296) was reviewed for patients who underwent retreatment for early (within 6 months) in-stent restenosis after carotid artery stenting (CAS). Six patients were identified. All were treated with cutting balloons. Procedural outcome and long-term follow-up was collected from the registry and hospital records.

Results

Cutting balloon angioplasty was technically successful and uncomplicated in all six treated patients. The procedure was durable in 5/6 (range of follow-up 3–36 months, median = 24 months).

Conclusions

Cutting balloon angioplasty is an effective initial treatment for severe carotid in-stent restenosis.
Shift work is a risk factor for increased total cholesterol level: a 14-year prospective cohort study in 6886 male workers
Authors: Dochi M , Suwazono Y , Sakata K , Okubo Y , Oishi M , Tanaka K , Kobayashi E , Nogawa K
Published: August 2009

Objectives:

The widespread adoption of 24 h continuous operations in a number of industries has resulted in an increase in shift work, which may influence lipid metabolism because of disturbed circadian rhythms, broken sleep and lifestyle problems. The objective of the present study was to assess the effect of shift work on serum total cholesterol as an index of lipid metabolism.

Methods:

A 14-year prospective cohort study was conducted in day workers (n = 4079) and alternating shift workers (n = 2807) who received annual health check-ups between 1991 and 2005 in a Japanese steel company. The end-points were either a 20%, 25%, 30%, 35%, 40% or 45% increase in serum total cholesterol during the period of observation, compared with serum total cholesterol at entry to the study. The association between the job schedule type and increase in serum total cholesterol was investigated using multivariate pooled logistic regression analyses. The odds ratios for the effect of shift work were obtained after adjustment for a number of potential confounders.

Results:

The significant odds ratios of alternating shift work (and 95% confidence intervals) were: ⩾20%, 1.16 (1.07 to 1.26); ⩾25%, 1.16 (1.05 to 1.28); ⩾35%, 1.23 (1.05 to 1.43); ⩾40%, 1.30 (1.07 to 1.58); and ⩾45%, 1.28 (1.01 to 1.63) for serum total cholesterol.

Conclusion:

Generally the odds ratios of alternating shift work tended to be higher for stricter cut-points of relative increase in serum total cholesterol level. Our study in male Japanese workers revealed that alternating shift work adversely affected lipid metabolism.
Associations of long- and short-term air pollution exposure with markers of inflammation and coagulation in a population sample
Authors: Panasevich S , Leander K , Rosenlund M , Ljungman P , Bellander T , de Faire U , Pershagen G , Nyberg F
Published: August 2009

Background:

Exposure to elevated levels of ambient air pollutants can lead to adverse cardiovascular effects. Potential mechanisms include systemic inflammation and perturbation of the coagulation balance.

Objectives:

To investigate long- and short-term effects of air pollution exposure on serum levels of inflammatory (IL-6, TNF-α and CRP) and coagulation (fibrinogen and PAI-1) markers relevant for cardiovascular pathology.

Methods:

The study group consisted of a population sample of 1028 men and 508 women aged 45–70 years from Stockholm. Long-term air pollution exposure was assessed using spatial modelling of traffic-related NO2and heating-related SO2emissions at each subject’s residential addresses over retrospective periods of 1, 5 and 30 years. Short-term exposure was assessed as averages of rooftop measurements over 12–120 h before blood sampling.

Results:

Long-term exposures to both traffic-NO2and heating-SO2emissions showed consistent associations with IL-6 levels. 30-year average traffic-NO2exposure was associated with a 64.5% (95% CI 6.7% to 153.8%) increase in serum IL-6 per 28.8 μg/m3(corresponding to the difference between the 5th and 95th percentile exposure value), and 30-year exposure to heating-SO2with a 67.6% (95% CI 7.1% to 162.2%) increase per 39.4 μg/m3(5th–95th percentile value difference). The association appeared stronger in non-smokers, physically active people and hypertensive subjects. We observed positive non-significant associations of inflammatory markers with NO2and PM10during 24 h before blood sampling. Short-term exposure to O3was associated with increased, and SO2with decreased, fibrinogen levels.

Conclusions:

Our results suggest that exposure to moderate levels of air pollution may influence serum levels of inflammatory markers.
Area of Attraction and Effective Area Fished by a Whelk (Buccinum undatum) Trap under Variable Conditions
Authors: McQuinn I. H. , Gendron L. , Himmelman J. H.
Published: August 2009

A study was conducted to examine the size and shape of the area of attraction, to evaluate the effective fishing area of a whelk (Buccinum undatum) trap under different physical and biotic conditions, and to validate the whelk density estimates as determined from the effective area. The study was conducted using a tag–recapture method in the Archipel de Mingan, Quebec. The effect of six different variables was examined (season, bait, depth, substratum, current, and stress). Current speed and direction were shown to be important in defining the size and shape of the area of attraction. Estimates of the effective area ranged from 18 to 278 m2. Lowest values were associated with relatively strong currents (26 cm∙s−1), while highest values were observed in July and when a less stressful tagging procedure was used. Behavioural factors, notably seasonal variations in feeding rates and reproductive activity, also appeared to affect the size of the effective area. Density estimates derived from the effective areas were comparable with SCUBA diving survey estimates. Our study shows that the effective area cannot be estimated as a single, gear-specific value. Effective area estimates must therefore be determined on a site- and season-specific basis if conditions affecting the catchability of whelks vary during the fishing season and/or over the fishing area.
Evaluation of Whole-Lake Nitrogen Fertilization for Controlling Blue-Green Algal Blooms in a Hypereutrophic Lake
Authors: Lathrop Richard C.
Published: August 2009

Indian Lake, a shallow hypereutrophic lake in southern Wisconsin, was treated with ammonium nitrate to test whether high dissolved inorganic nitrogen (DIN) concentrations or high total nitrogen to phosphorus (N:P) ratios could prevent the development of summer blue-green algal blooms (predominately Microcystis aeruginosa). The fertilizer was applied weekly from late April to early July 1981–82 in annual amounts of 14 and 23 g N/m2, respectively. In 1981, a dense summer blue-green algal bloom developed, although both dissolved inorganic phosphorus (DIP) and algal P (particulate P/chlorophyll a) were lower than in summers without fertilizer treatments. In 1982, unusually clear water in May allowed aquatic macrophytes and associated filamentous algae to become very dense in June. The increase in water clarity and macrophytes was probably a response to a fishkill the previous winter. Later in the summer the macrophyte community disappeared and a blue-green algal bloom developed. After each fertilization in both treatment years, the NH4+ and NO3− decreased rapidly, suggesting nitrification/denitrification in the lake sediments. Whole-lake N fertilization did not prevent the summer blue-green algal blooms in Indian Lake. Low DIN apparently does not trigger the bloom development or cause the vernal nonblue-green algae to decline. Also, Sow total N:P ratios (<11 by weight) during the blooms occur partly because of high DIP and because of high algal P levels resulting from luxury P consumption. The Indian Lake data suggest that low total N:P ratios are only predictive of (or resultant from) blue-green algal blooms rather than causative.