bluuebunny/crossref_metadata_2025 huggingface dataset:
Exploring the Importance of Business Clockspeed as a Moderator for Determinants of Supplier Network Performance*
Authors: Guimaraes Tor , Cook Dave , Natarajan Nat
Published: June 2007

As the importance of supplier networks becomes increasingly recognized as a vital factor to company performance, researchers and practitioners alike are focusing their attention on this subject. The study's main objective is to test the specific hypotheses that effective use of Information Technology (IT) and the depth of company relationships with suppliers are directly related to Supplier Network (SN) performance, and that industry clockspeed moderates these relationships. A convenience sample of 135 manufacturing organizations was used to empirically test these hypotheses. Our results indicate that clockspeed does moderate the relationship between IT use effectiveness and supplier network performance. The same is true in the case of supplier relations depth, and hence, managers are encouraged to pay attention to the items comprising network performance as a determinant of supplier network performance.
Foraging specialisms, prey size and life‐history patterns: a test of predictions using sympatric polymorphic Arctic charr (Salvelinus alpinus)
Authors: Fraser D. , Huntingford F. A. , Adams C. E.
Published: June 2007

Abstract –  We use arguments based on optimal foraging theory to predict body size constraints and the consequences of these on a range of life‐history traits in three trophic specialist morphs of Arctic charr, Salvelinus alpinus, living in sympatry in Loch Rannoch, Scotland. As predicted, foraging specialists feeding on small prey items with a narrow size range showed evidence of deterministic growth; the ultimate body size of macrobenthos feeders being larger (L∞ = 238 mm) than that of planktivores (L∞ = 216 mm). In contrast, the piscivorous morph showed no evidence of reaching a maximal body size.

The two size‐constrained morphs (benthivores and planktivores) matured earlier and died younger (living for up to 11 and 7 years, respectively, in this study) than did the piscivorous charr which showed continuous growth up to at least 17 years.

The pattern of annual reproductive investment in maturing individuals was complex. Planktivores invested in larger eggs than the other two forms, but benthivores produced a greater number of eggs than planktivores, which in turn produced more than piscivores. Planktivorous males had a greater investment in mean testis weight than the other two forms.

Lifetime reproductive output was the greatest in the benthivorous charr, intermediate in planktivorous and the lowest in the piscivorous charr when measured either as fecundity or as gonadal weight. We conclude that constraints imposed upon foraging specialists by foraging efficiency is a significant driver of body size and ultimately reproductive investment in gape‐limited foraging salmonids.
ESE‐1 inhibits the invasion of oral squamous cell carcinoma in conjunction with MMP‐9 suppression
Authors: Iwai S , Amekawa S , Yomogida K , Sumi T , Nakazawa M , Yura Y , Nishimune Y , Nozaki M
Published: June 2007

Objectives:  Matrix metalloproteinases (MMPs) regulated by ets transcription factors facilitate carcinoma cell invasion. An ets family member, ESE‐1, is expressed specifically in epithelial tissues, but its association with MMPs is obscure. In this study, we investigated whether ESE‐1 regulates invasion of oral squamous cell carcinoma (SCC) via transcriptional activity of MMP‐9.

Methods:  HSC‐3 and KB were used as human oral SCC lines. The expression of ESE‐1 and MMP‐9 was detected by in situ hybridization and immunohistochemistry. Invasion assay, gelatin zymography and Northern blotting were used to detect the invasion activity, the gelatinolytic activity and the expression of MMP‐9 in the ESE‐1 transfectants. Luciferase assays and mutation analysis were used for the transcriptional analysis of MMP‐9 promoter region by ESE‐1.

Results:  ESE‐1 was expressed in the intermediate layer but not in the invasive area, in which MMP‐9 was expressed, in the oral SCC tissues. ESE‐1 suppressed invasion activity and 92 kDa gelatinolytic activity in HSC‐3 as a result of transfection. ESE‐1 regulates MMP‐9 expression in a negative manner and the ets binding site on the MMP‐9 promoter contributed to suppression by ESE‐1.

Conclusions:  These findings indicate that ESE‐1 negatively regulates the invasion of oral SCC via transcriptional suppression of MMP‐9.
Why do young women smoke? V. Role of direct and interactive effects of nicotinic cholinergic receptor gene variation on neurocognitive function
Authors: Rigbi A. , Kanyas K. , Yakir A. , Greenbaum L. , Pollak Y. , Ben‐Asher E. , Lancet D. , Kertzman S. , Lerer B.
Published: June 2007

Previous work suggests that young women who smoke cigarettes regularly, or did so in the past, manifest a neurocognitive profile that is characterized by small but significant impairments of response inhibition and attention. The present study sought to determine whether variation in nicotinic cholinergic receptor (nAchR) genes impacts upon cognitive function in these domains by overall or differential effects on the performance of current, former and non‐smokers. The study sample consisted of 100 female college students, current or past smokers, and 144 who had never smoked. All performed a computerized neurocognitive test battery and were genotyped for 39 single nucleotide polymorphisms in 11 nAchR genes. The results, derived from linear or logistic regression, show significant direct and interactive relationships between single nucleotide polymorphisms and haplotypes in several nAchR genes and performance on the Matching Familiar Figures Test (MFFT) Stroop test, Continuous Performance Task (CPT) and Tower of London (TOL) test. Response inhibition (MFFT, Stroop, CPT Loading Phase, TOL) was associated with variants in CHRNA2, CHRNA4, CHRNA5, CHRNA7, CHRNA9, CHRNA10, CHRNB2 and CHRNB3. Selective attention (Stroop) was associated with CHRNA4, CHRNA5, CHRNA9 and CHRNB2. Sustained attention (CPT Boring Phase) was associated with CHRNA4, CHRNA5, CHRNA7, CHRNA10 and CHRNB3. Up to 37% of the variance among the smokers and up to 47% of the variance among the non‐smokers on the test measures was explained. Differences between smokers and non‐smokers in neurocognitive function, putatively implicated in susceptibility to nicotine dependence, may be modulated by variants in nAchR genes, with potential implications for prevention and treatment.
Autism‐like behavioral phenotypes in BTBR T+tf/J mice
Authors: McFarlane H. G. , Kusek G. K. , Yang M. , Phoenix J. L. , Bolivar V. J. , Crawley J. N.
Published: June 2007

Autism is a behaviorally defined neurodevelopmental disorder of unknown etiology. Mouse models with face validity to the core symptoms offer an experimental approach to test hypotheses about the causes of autism and translational tools to evaluate potential treatments. We discovered that the inbred mouse strain BTBR T+tf/J (BTBR) incorporates multiple behavioral phenotypes relevant to all three diagnostic symptoms of autism. BTBR displayed selectively reduced social approach, low reciprocal social interactions and impaired juvenile play, as compared with C57BL/6J (B6) controls. Impaired social transmission of food preference in BTBR suggests communication deficits. Repetitive behaviors appeared as high levels of self‐grooming by juvenile and adult BTBR mice. Comprehensive analyses of procedural abilities confirmed that social recognition and olfactory abilities were normal in BTBR, with no evidence for high anxiety‐like traits or motor impairments, supporting an interpretation of highly specific social deficits. Database comparisons between BTBR and B6 on 124 putative autism candidate genes showed several interesting single nucleotide polymorphisms (SNPs) in the BTBR genetic background, including a nonsynonymous coding region polymorphism in Kmo. The Kmo gene encodes kynurenine 3‐hydroxylase, an enzyme‐regulating metabolism of kynurenic acid, a glutamate antagonist with neuroprotective actions. Sequencing confirmed this coding SNP in Kmo, supporting further investigation into the contribution of this polymorphism to autism‐like behavioral phenotypes. Robust and selective social deficits, repetitive self‐grooming, genetic stability and commercial availability of the BTBR inbred strain encourage its use as a research tool to search for background genes relevant to the etiology of autism, and to explore therapeutics to treat the core symptoms.
Success Factors for Managing International Joint Ventures: A Review and an Integrative Framework
Authors: Nippa Michael , Beechler Schon , Klossek Andreas
Published: June 2007

International joint ventures (IJV) are an important organizational mode for expanding and sustaining global business and have been of special relevance for the emerging Chinese market for decades. While IJVs offer specific economic advantages they also present serious management problems that lead to high failure rates, especially in developing countries. Because of the strategic relevance of IJVs and corresponding management challenges, research on success factors for managing IJVs in China has received broad attention, resulting in a variety of studies. However, there are no conceptual syntheses of the literature to date and further development in the field is hampered by both a lack of consolidation of what is known and identification of viable avenues for future research. We address this gap by building on existing concepts in the field, developing them further and synthesizing them into an integrative, theory-based framework of IJV success factors. We use this framework to systematically depict the results of both empirical studies related to Sino-foreign IJVs and to IJVs in general. Finally, we draw important implications from the research and propose potential paths for future study.
EMINENT DOMAIN: UNUSED TOOL FOR AMERICAN LABOR?
Authors: Ranis Peter
Published: June 2007

The deindustrialization of America with the concomitant loss of decent paying jobs, the rise of unemployment, and the increasing poverty among the working class requires a novel response. The challenges of “free trade,” globalization and international competition and technological change are all threatening the viability of the labor movement in the U.S. The use of eminent domain offers a meaningful tool that can be implemented to counter this trend. Eminent domain has been legally used and constitutionally sanctioned for community, infrastructure, and development purposes. The time is ripe for a broad‐based coalition of legislatures, community interests, labor unions, and social movements to promote the use of eminent domain to expropriate with compensation enterprises in danger of being abandoned and moved offshore by their owners. Decisions by the owners of enterprises have repercussions and societal externalities that legitimize the rights to regulate them by way of eminent domain on behalf of the public interest. Workers in cooperatives in both the U.S. and throughout the world have shown that they can run factories and enterprises without owners and managers if given the necessary financial and legal wherewithal.
IMPROVING THE ENFORCEMENT OF RESTRAINING ORDERS AFTER CASTLE ROCK V. GONZALES*
Authors: Talwar Mandeep
Published: June 2007

After the U.S. Supreme Court's decision in Castle Rock, reliance on domestic violence restraining orders does not offer the solution in and of itself. Our legal system needs to provide greater protection for victims of domestic violence. This note explores ways to use risk assessment tools to augment restraining orders, in addition to examining integrated domestic violence courts that take a proactive approach to aiding victims of abuse.
Decrease in accumulation of ultrasound contrast microbubbles in non‐alcoholic steatohepatitis
Authors: Iijima Hiroko , Moriyasu Fuminori , Tsuchiya Kaoru , Suzuki Shiro , Yoshida Masahiro , Shimizu Masafumi , Sasaki Shunichi , Nishiguchi Syuhei , Maeyama Shiro
Published: June 2007

Aim: Non‐alcoholic steatohepatitis (NASH) is one of the representative liver diseases in developed countries. Diagnosis of NASH is dependent on histological findings from liver biopsy.

Methods: The usefulness of contrast ultrasound with Levovist for diagnosis of NASH is described. 2.5 g of ultrasound contrast agent Levovist was injected intravenously. The liver was scanned at 5, 10, 15, 20, 30, 40 and 50 min and changes in microbubble accumulation were evaluated. The signal intensity from regions of interest (ROI) on the contrast images was measured and estimated using time intensity curves (TICs). Twenty‐one patients with NASH, 33 with non‐alcoholic fatty liver disease (NAFLD) and 10 healthy volunteers (HV) were studied. The signal intensity was measured quantitatively at 5 and 20 min after injection.

Results: There was a statistically significant decrease in NASH, when compared with NAFLD and HV groups. These changes in signal intensity were not correlated to the degree of fibrosis and steatosis in histological study. The sensitivity, specificity and overall accuracy obtained from the receiver operating characteristic (ROC) curve were 100% when the cut‐off value was set at 43.6 of signal intensity at 20 min.

Conclusion: The Levovist contrast study is a useful screening examination which picks up NASH among fatty liver patients.
Development of quality control standards for radiation therapy equipment in Canada
Authors: Dunscombe Peter , Johnson Harry , Arsenault Clement , Mawko George , Bissonnette Jean‐Pierre , Seuntjens Jan
Published: June 2007

Among the essential components of a comprehensive quality assurance program in radiotherapy are the quality control protocols to be used on the equipment and, in particular, the performance objectives and criteria. In the present work, we describe the development of a suite of quality control documents for use across Canada. Following a generic format, we are generating concise, clear standards for the most commonly used equipment in radiotherapy, with the emphasis on performance measures. The final standards of performance are confirmed following cross‐country consultation facilitated by the availability of draft documents on the Canadian Medical Physics web site.

PACS number: 87.53.Xd
Imaging Atomic Structure and Dynamics with Ultrafast X-ray Scattering
Authors: Gaffney K. J. , Chapman H. N.
Published: June 2007

Measuring atomic-resolution images of materials with x-ray photons during chemical reactions or physical transformations resides at the technological forefront of x-ray science. New x-ray–based experimental capabilities have been closely linked with advances in x-ray sources, a trend that will continue with the impending arrival of x-ray–free electron lasers driven by electron accelerators. We discuss recent advances in ultrafast x-ray science and coherent imaging made possible by linear-accelerator–based light sources. These studies highlight the promise of ultrafast x-ray lasers, as well as the technical challenges and potential range of applications that will accompany these transformative x-ray light sources.
A Meta-Analysis of Effects of Bt Cotton and Maize on Nontarget Invertebrates
Authors: Marvier Michelle , McCreedy Chanel , Regetz James , Kareiva Peter
Published: June 2007

Although scores of experiments have examined the ecological consequences of transgenic
Bacillus thuringiensis
(Bt) crops, debates continue regarding the nontarget impacts of this technology. Quantitative reviews of existing studies are crucial for better gauging risks and improving future risk assessments. To encourage evidence-based risk analyses, we constructed a searchable database for nontarget effects of Bt crops. A meta-analysis of 42 field experiments indicates that nontarget invertebrates are generally more abundant in Bt cotton and Bt maize fields than in nontransgenic fields managed with insecticides. However, in comparison with insecticide-free control fields, certain nontarget taxa are less abundant in Bt fields.
Comment on "From Plant Traits to Plant Communities: A Statistical Mechanistic Approach to Biodiversity"
Authors: Marks Christian O. , Muller-Landau Helene C.
Published: June 2007

Shipley
et al
. (Reports, 3 November 2006, p. 812) predicted plant community composition and relative abundances with a high level of accuracy by maximizing Shannon's index of information entropy (species diversity), subject to constraints on plant trait averages. We show that the entropy maximization assumption is relatively unimportant and that the high accuracy is due largely to a statistical effect.
An Ancient Mechanism Controls the Development of Cells with a Rooting Function in Land Plants
Authors: Menand Benoît , Yi Keke , Jouannic Stefan , Hoffmann Laurent , Ryan Eoin , Linstead Paul , Schaefer Didier G. , Dolan Liam
Published: June 2007

Root hairs and rhizoids are cells with rooting functions in land plants. We describe two basic helix-loop-helix transcription factors that control root hair development in the sporophyte (2
n
) of the angiosperm
Arabidopsis thaliana
and rhizoid development in the gametophytes (
n
) of the bryophyte
Physcomitrella patens
. The phylogeny of land plants supports the hypothesis that early land plants were bryophyte-like and possessed a dominant gametophyte and later the sporophyte rose to dominance. If this hypothesis is correct, our data suggest that the increase in morphological complexity of the sporophyte body in the Paleozoic resulted at least in part from the recruitment of regulatory genes from gametophyte to sporophyte.
Molecular Typing of Isolates ofRickettsia rickettsiiby Use of DNA Sequencing of Variable Intergenic Regions
Authors: Karpathy Sandor E. , Dasch Gregory A. , Eremeeva Marina E.
Published: June 2007

Rickettsia rickettsii, the causative agent of Rocky Mountain spotted fever, is found throughout the Americas, where it is associated with different animal reservoirs and tick vectors. No molecular typing system currently exists to allow for the robust differentiation of isolates ofR. rickettsii. Analysis of eight completed genome sequences of rickettsial species revealed a high degree of sequence conservation within the coding regions of chromosomes in the genus. Intergenic regions between coding sequences should be under less selective pressure to maintain this conservation and thus should exhibit greater nucleotide polymorphisms. Utilizing these polymorphisms, we developed a molecular typing system that allows for the genetic differentiation of isolates ofR. rickettsii. This typing system was applied to a collection of 38 different isolates collected from humans, animals, and tick vectors from different geographic locations. Serotypes 364D, fromDermacentor occidentalisticks, and Hlp, fromHaemaphysalis leporispalustristicks, appear to be distinct genotypes that may not belong to the speciesR. rickettsii. We were also able to differentiate 36 historical isolates ofR. rickettsiiinto three different phylogenetic clades containing seven different genotypes. This differentiation correlated well, but not perfectly, with the geographic origin and likely tick vectors associated with the isolates. The few apparent typing discrepancies found suggest that the molecular ecology ofR. rickettsiineeds more investigation.
Rapid Identification of Viridans Streptococci by Mass Spectrometric Discrimination
Authors: Friedrichs C. , Rodloff A. C. , Chhatwal G. S. , Schellenberger W. , Eschrich K.
Published: June 2007

Viridans streptococci (VS) are responsible for several systemic diseases, such as endocarditis, abscesses, and septicemia. Unfortunately, species identification by conventional methods seems to be more difficult than species identification of other groups of bacteria. The aim of the present study was to evaluate the use of cell matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF-MS) for the rapid identification of 10 different species of VS. A total of 99 VS clinical isolates, 10 reference strains, and 20 strains from our in-house culture collection were analyzed by MALDI-TOF-MS. To evaluate the mass-spectrometric discrimination results, all strains were identified in parallel by phenotypic and genotypic methods. MALDI-TOF-MS identified 71 isolates as the mitis group, 23 as the anginosus group, and 5 as
Streptococcus salivarius
. Comparison of the species identification results obtained by the MALDI-TOF-MS analyses and with the phenotypic/genotypic identification systems showed 100% consistency at the species level. Thus, MALDI-TOF-MS seems to be a rapid and reliable method for the identification of species of VS from clinical samples.
Development of Multiple-Locus Variable-Number Tandem-Repeat Analysis for
Yersinia enterocolitica
subsp.
palearctica
and Its Application to Bioserogroup 4/O3 Subtyping
Authors: Gierczyński Rafał , Golubov Andrey , Neubauer Heinrich , Pham Jeannette N. , Rakin Alexander
Published: June 2007

Yersinia enterocolitica
bioserogroup 4/O3 is the predominant causative agent of yersiniosis in Europe and North America. Multiple-locus variable-number tandem-repeat analysis (MLVA) was developed to improve the resolution power of classical genotyping methods. MLVA based on six loci was able to distinguish 76 genotypes among 91
Y. enterocolitica
isolates of worldwide origin and 41 genotypes among 51 nonepidemiologically linked bioserogroup 4/O3 isolates, proving that it has a high resolution power. However, only a slight correlation of the MLVA genotypes and the geographic distribution of the isolates was observed. Although MLVA was also capable of distinguishing strains of
Y. enterocolitica
subsp.
palearctica
O9 and O5,27, there was only a minor correlation between the MLVA genotypes and serogroups. MLVA may be a helpful tool for epidemiological investigations of
Y. enterocolitica
subsp.
palearctica
outbreaks.
Gray Foxes (Urocyon cinereoargenteus) as a Potential Reservoir of aBartonella clarridgeiae-Like Bacterium and Domestic Dogs as Part of a Sentinel System for Surveillance of Zoonotic Arthropod-Borne Pathogens in Northern California
Authors: Henn Jennifer B. , Gabriel Mourad W. , Kasten Rickie W. , Brown Richard N. , Theis Jerold H. , Foley Janet E. , Chomel Bruno B.
Published: June 2007

Two species ofBartonella, a novelBartonella clarridgeiae-like bacterium andB. vinsoniisubsp.berkhoffii, were isolated from rural dogs and gray foxes in northern California. A novelB. clarridgeiae-like species was isolated from 3 (1.7%) of 182 dogs and 22 (42%) of 53 gray foxes, whileB. vinsoniisubsp.berkhoffiiwas isolated from 1 dog (0.5%) and 5 gray foxes (9.4%). PCR and DNA sequence analyses of the citrate synthase (gltA) gene and the 16S-23S intergenic spacer region suggested that strains infecting dogs and gray foxes were identical. Fifty-four dogs (29%) and 48 gray foxes (89%) had reciprocal titers of antibodies againstBartonellaspp. of ≥64. The high prevalence of bacteremia and seroreactivity toBartonellaspp. in gray foxes suggests that they may act as a reservoir species for theB. clarridgeiae-like species in this region. Domestic dogs were also tested for other arthropod-borne infectious agents. Fifty-one dogs (28%) were positive forDirofilaria immitisantigen, seventy-four (40%) were seroreactive toAnaplasma phagocytophilum, and five (2.7%) were seropositive forYersinia pestis. Fourteen dogs (7.6%) were PCR positive forA. phagocytophilum. Polytomous logistic regression models were used to assess the association ofBartonellaantibody titer categories with potential risk factors and the presence of other vector-borne agents in domestic dogs. Older dogs were more likely to be seroreactive toBartonellaspp. There was no association between the exposure of dogs toBartonellaand the exposure of dogs toA. phagocytophilumin this study.
Expression of the Mu Opioid Receptor in the Human Immunodeficiency Virus Type 1 Transgenic Rat Model
Authors: Chang Sulie L. , Beltran Jose A. , Swarup Shilpa
Published: June 2007

Opioids, via the mu opioid receptor (MOR), can exacerbate bacterial infections and the immunopathogenesis of human immunodeficiency virus type 1 (HIV-1) infection. Recently, an HIV-1 transgenic (HIV-1Tg) rat model containing circulating HIV-1 gp120 was created. Using real-time reverse transcription-PCR, we found that MOR mRNA levels were significantly higher in the peritoneal macrophages of the HIV-1Tg rat than those in control animals. Lipopolysaccharide, a bacterial endotoxin, induced secretion of the inflammatory cytokines tumor necrosis factor alpha (TNF-α), interleukin-β (IL-β), and IL-10 in the HIV-1Tg rat and further increased MOR expression. Ex vivo studies showed that MOR expression was up-regulated in the peritoneal macrophages of F344 control rats by exposure to serum from HIV-1Tg rats and that MOR up-regulation was abolished by addition of gp120 antibody to the serum. In human TPA-differentiated HL-60 cells, which are macrophage-like cells, LPS-induced MOR mRNA up-regulation was greater in gp120-pretreated cells than in vehicle-pretreated cells. Our data suggest that in individuals infected with HIV-1, the MOR is up-regulated, possibly by circulating HIV-1 proteins such as gp120, and HIV-1 proteins may play a significant role in modulating the response to bacterial infection in opioid-using HIV-infected individuals. Furthermore, our results demonstrate that the new HIV-1Tg rat model can be a valuable tool with which to study MOR gene expression and its effects in the continuous presence of HIV viral proteins.
Multiple-Cytokine-Producing Antiviral CD4 T Cells Are Functionally Superior to Single-Cytokine-Producing Cells
Authors: Kannanganat Sunil , Ibegbu Chris , Chennareddi Lakshmi , Robinson Harriet L. , Amara Rama Rao
Published: June 2007

Virus-specific CD4 T cells are endowed with multiple functions, such as cytokine production, CD40 ligand (CD40L) expression (associated with the costimulation of CD8 and B cells), and degranulation (associated with cytotoxic potential). Here, we used antiviral CD4 T cells present in human blood to evaluate the relationship between cytokine production and other functions of CD4 T cells. Antiviral CD4 T cells specific for a virus causing persistent infection, cytomegalovirus (CMV), and two viruses causing nonpersistent infections, influenza virus and the smallpox vaccine virus (vaccinia virus), were studied. CD4 T cells specific for each of the viruses produced all seven possible combinations of the cytokines gamma interferon (IFN-γ), interleukin-2, and tumor necrosis factor alpha. Cells producing three or two cytokines (triple producers and double producers) represented nearly 50% of the total response to each of the viruses. Triple producers expressed the highest levels of cytokines per cell, and single producers expressed the lowest. Following stimulation, higher frequencies of triple producers than single producers expressed CD40L. Only CMV-specific CD4 T cells underwent degranulation. However, higher frequencies of CMV-specific triple producers than single producers showed this functional characteristic. In contrast to the functional phenotypes, the memory phenotypes of triple producers and IFN-γ single producers did not differ. These results demonstrate a strong positive association between the cytokine coproduction capacity of a virus-specific CD4 T cell and its other functional characteristics and suggest that vaccines should aim to elicit T cells that coproduce more than one cytokine.
A Protein Kinase A-Dependent Mechanism by Which Rotavirus Affects the Distribution and mRNA Level of the Functional Tight Junction-Associated Protein, Occludin, in Human Differentiated Intestinal Caco-2 Cells
Authors: Beau Isabelle , Cotte-Laffitte Jacqueline , Amsellem Raymonde , Servin Alain L.
Published: June 2007

We found that at the tight junctions (TJs) of Caco-2 cell monolayers, rhesus monkey rotavirus (RRV) infection induced the disappearance of occludin. Confocal laser scanning microscopy showed the disappearance of occludin from the cell-cell boundaries without modifying the expression of the other TJ-associated proteins, ZO-1 and ZO-3. Western immunoblot analysis of RRV-infected cells showed a significant fall in the levels of the nonphosphorylated form of occludin in both Triton X-100-insoluble and Triton X-100-soluble fractions, without any change in the levels of the phosphorylated form of occludin. Quantitative reverse transcription-PCRs revealed that the level of transcription of the gene that encodes occludin was significantly reduced in RRV-infected cells. Treatment of RRV-infected cells with Rp-cyclic AMP and protein kinase A inhibitors H89 and KT5720 during the time course of the infection restored the distribution of occludin and a normal level of transcription of the gene that encodes occludin.
Tissue-Specific and Inducer-Specific Differential Induction of ISG56 and ISG54 in Mice
Authors: Terenzi Fulvia , White Christine , Pal Srabani , Williams Bryan R. G. , Sen Ganes C.
Published: June 2007

The interferon-stimulated genes (ISGs) ISG56 and ISG54 are strongly induced in cultured cells by type I interferons (IFNs), viruses, and double-stranded RNA (dsRNA), which activate their transcription by various signaling pathways. Here we studied the stimulus-dependent induction of both genes in vivo. dsRNA, which is generated during virus infection, induced the expression of both genes in all organs examined. Induction was not seen in STAT1-deficient mice, indicating that dsRNA-induced gene expression requires endogenous IFN. We further examined the regulation of these ISGs in several organs from mice injected with dsRNA or IFN-β. Both ISG56 and ISG54 were widely expressed and at comparable levels. However, in organs isolated from mice injected with IFN-α the expression of ISG54 was reduced and more restricted in distribution compared with the expression level and distribution of ISG56. When we began to study specific cell types, splenic B cells showed ISG54 but not ISG56 expression in response to all agonists. Finally, in livers isolated from mice infected with vesicular stomatitis virus, the expression of ISG56, but not ISG54, was induced; this difference was observed at both protein and mRNA levels. These studies have revealed unexpected complexity in IFN-stimulated gene induction in vivo. For the first time we showed that the two closely related genes are expressed in a tissue-specific and inducer-specific manner. Furthermore, our findings provide the first evidence of a differential pattern of expression of ISG54 and ISG56 genes by IFN-α and IFN-β.
Molecular Changes in the Polymerase Genes (PA and PB1) Associated with High Pathogenicity of H5N1 Influenza Virus in Mallard Ducks
Authors: Hulse-Post D. J. , Franks J. , Boyd K. , Salomon R. , Hoffmann E. , Yen H. L. , Webby R. J. , Walker D. , Nguyen T. D. , Webster R. G.
Published: June 2007

The highly pathogenic (HP) influenza viruses H5 and H7 are usually nonpathogenic in mallard ducks. However, the currently circulating HP H5N1 viruses acquired a different phenotype and are able to cause mortality in mallards. To establish the molecular basis of this phenotype, we cloned the human A/Vietnam/1203/04 (H5N1) influenza virus isolate that is highly pathogenic in ferrets, mice, and mallards and found it to be a heterogeneous mixture. Large-plaque isolates were highly pathogenic to ducks, mice, and ferrets, whereas small-plaque isolates were nonpathogenic in these species. Sequence analysis of the entire genome revealed that the small-plaque and the large-plaque isolates differed in the coding of five amino acids. There were two differences in the hemagglutinin (HA) gene (K52T and A544V), one in the PA gene (T515A), and two in the PB1 gene (K207R and Y436H). We inserted the amino acid changes into the wild-type reverse genetic virus construct to assess their effects on pathogenicity in vivo. The HA gene mutations and the PB1 gene K207R mutation did not alter the HP phenotype of the large-plaque virus, whereas constructs with the PA (T515A) and PB1 (Y436H) gene mutations were nonpathogenic in orally inoculated ducks. The PB1 (Y436H) construct was not efficiently transmitted in ducks, whereas the PA (T515A) construct replicated as well as the wild-type virus did and was transmitted efficiently. These results show that the PA and PB1 genes of HP H5N1 influenza viruses are associated with lethality in ducks. The mechanisms of lethality and the perpetuation of this lethal phenotype in ducks in nature remain to be determined.
Recombination Confounds the Early Evolutionary History of Human Immunodeficiency Virus Type 1: Subtype G Is a Circulating Recombinant Form
Authors: Abecasis Ana B. , Lemey Philippe , Vidal Nicole , de Oliveira Túlio , Peeters Martine , Camacho Ricardo , Shapiro Beth , Rambaut Andrew , Vandamme Anne-Mieke
Published: June 2007

Human immunodeficiency virus type 1 (HIV-1) is classified in nine subtypes (A to D, F, G, H, J, and K), a number of subsubtypes, and several circulating recombinant forms (CRFs). Due to the high level of genetic diversity within HIV-1 and to its worldwide distribution, this classification system is widely used in fields as diverse as vaccine development, evolution, epidemiology, viral fitness, and drug resistance. Here, we demonstrate how the high recombination rates of HIV-1 may confound the study of its evolutionary history and classification. Our data show that subtype G, currently classified as a pure subtype, has in fact a recombinant history, having evolved following recombination between subtypes A and J and a putative subtype G parent. In addition, we find no evidence for recombination within one of the lineages currently classified as a CRF, CRF02_AG. Our analysis indicates that CRF02_AG was the parent of the recombinant subtype G, rather than the two having the opposite evolutionary relationship, as is currently proposed. Our results imply that the current classification of HIV-1 subtypes and CRFs is an artifact of sampling history, rather than reflecting the evolutionary history of the virus. We suggest a reanalysis of all pure subtypes and CRFs in order to better understand how high rates of recombination have influenced HIV-1 evolutionary history.
Hydrophobic Residues That Form Putative Fusion Loops of Epstein-Barr Virus Glycoprotein B Are Critical for Fusion Activity
Authors: Backovic Marija , Jardetzky Theodore S. , Longnecker Richard
Published: June 2007

To test the importance of the hydrophobic residues within the putative Epstein-Barr virus (EBV) glycoprotein B (gB) fusion loops in membrane fusion, WY
112-113
and WLIW
193-196
were mutated into alanine, glutamic acid, or the analogous residues from herpes simplex virus type 1 (HSV-1) gB (HR and RVEA). All gB variants exhibited cell surface expression, demonstrating that the substitutions did not perturb gB trafficking. None of six gB variants was, however, capable of mediating fusion with either epithelial or B cells. These data demonstrate that the bulky and hydrophobic EBV loop residues, which differ from the more hydrophilic HSV-1 residues and appear more compatible with membrane insertion, are essential for EBV gB-dependent fusion.
Evolutionary Processes among Sylvatic Dengue Type 2 Viruses
Authors: Vasilakis Nikos , Holmes Edward C. , Fokam Eric B. , Faye Ousmane , Diallo Mawlouth , Sall Amadou A. , Weaver Scott C.
Published: June 2007

Sylvatic dengue viruses (DENV) are transmitted in an enzootic cycle between nonhuman primates and arboreal
Aedes
mosquitoes in Southeast Asia and West Africa. Although previous analyses have revealed the evolutionary processes among endemic (human) DENV, little is known about viral evolution in the sylvatic cycle. Through an analysis of 14 complete coding regions of sylvatic Dengue type 2 virus sampled over a 33-year period, we show that both the rate of evolutionary change and the pattern of natural selection are similar among endemic and sylvatic DENV, although the latter have a uniquely high frequency of positive selection in the NS4B protein gene. Our findings support a recent cross-species transmission event and suggest the possibility of future DENV reemergence from the sylvatic cycle.
Atrial natriuretic peptide contribution to lipid mobilization and utilization during head-down bed rest in humans
Authors: Moro Cédric , Pillard Fabien , de Glisezinski Isabelle , Crampes François , Thalamas Claire , Harant Isabelle , Marques Marie-Adeline , Lafontan Max , Berlan Michel
Published: June 2007

Head-down bed rest (HDBR) increases plasma levels of atrial natriuretic peptide (ANP) and decreases norepinephrine levels. We previously demonstrated that ANP promotes lipid mobilization and utilization, an effect independent of sympathetic nervous system activation, when infused into lean healthy men at pharmacological doses. The purpose of the present study was to demonstrate that a physiological increase in ANP contributes to lipid mobilization and oxidation in healthy young men. Eight men were positioned for 4 h in a sitting (control) or in a HDBR position. Indexes of lipid mobilization and hormonal changes were measured in plasma. Extracellular glycerol, an index of lipolysis, was determined in subcutaneous adipose tissue (SCAT) with a microdialysis technique. A twofold increase in plasma ANP concentration was observed after 60 min of HDBR, and a plateau was maintained thereafter. Plasma norepinephrine decreased by 30–40% during HDBR, while plasma insulin and glucose levels did not change. The level of plasma nonesterified fatty acids was higher during HDBR. SCAT lipolysis, as reflected by interstitial glycerol, as well as interstitial cGMP, the second messenger of the ANP pathway, increased during HDBR. This was associated with an increase in blood flow observed throughout HDBR. Significant changes in respiratory exchange ratio and percent use of lipid and carbohydrate were seen only after 3 h of HDBR. Thus the proportion of lipid oxidized increased by 40% after 3 h of HDBR. The rise in plasma ANP during HDBR was associated with increased lipolysis in SCAT and whole body lipid oxidation. In this physiological setting, independent of increasing catecholamines, our study suggests that ANP contributes to lipid mobilization and oxidation in healthy young men.
Calcium regulation of endothelin-1 synthesis in rat inner medullary collecting duct
Authors: Strait Kevin A. , Stricklett Peter K. , Kohan Jessica L. , Miller Margaux B. , Kohan Donald E.
Published: June 2007

Collecting duct-derived endothelin-1 (ET-1) reduces blood pressure and inhibits Na and water reabsorption. Collecting duct ET-1 production is increased by volume expansion; however, the mechanism by which this occurs is unknown. We hypothesized that intracellular calcium, which is likely to be increased by volume expansion, regulates collecting duct ET-1 synthesis. Rat inner medullary collecting ducts (IMCD) were studied in primary culture. ET-1 release was decreased by 50–70% after chelation of intracellular calcium (BAPTA) or inhibition of CaM (W7) or CaMK (KN-93). These agents reduced ET-1 mRNA to a similar degree. CaM inhibition did not affect ET-1 mRNA stability. Transfection of IMCD with rat ET-1 promoter-luciferase constructs revealed maximal activity within 1.7 kb 5′ to the transcription start site; 5, 20, 35, and 90% of this activity were in the 0.08-, 0.37-, 1.0-, and 3.0-kb promoter regions, respectively. W7 markedly inhibited activity of the 3.0-kb but not 0.37- or 1.0-kb promoter regions. In contrast, W7 did not affect ET-1 release by rat aortic endothelial cells. Furthermore, transfected endothelial cells had maximal activity in the 0.37-kb region (as compared with the 1.7- and 3.0-kb regions), whereas W-7 had no effect on the activity of any of these promoter regions. In summary, IMCD ET-1 synthesis is regulated by calcium/CaM/CaMK-dependent pathways. The calcium/CaM-sensitive pathway is active in IMCD, but not endothelial cells. This suggests that IMCD-specific enhancer elements exist within the ET-1 promoter that confer unique calcium responsiveness.
Novel sandwich ELISA for human angiotensinogen
Authors: Katsurada Akemi , Hagiwara Yoshiaki , Miyashita Kazuya , Satou Ryousuke , Miyata Kayoko , Ohashi Naro , Navar L. Gabriel , Kobori Hiroyuki
Published: June 2007

We recently reported that urinary excretion rates of angiotensinogen (UAGT) provide a specific index of intrarenal renin-angiotensin (ANG) system (RAS) status in ANG II-dependent hypertensive rats. When this is shown to be applicable to human subjects, a diagnostic test to identify those hypertensive patients most likely to respond to an RAS blockade could provide useful information to allow a mechanistic rationale for selection of an optimized approach to treatment of hypertensive patients. However, simple and accurate methods to measure human angiotensinogen (hAGT) are unavailable. For future studies of human subjects, we developed antibodies and a sensitive and specific quantification system for hAGT using a sandwich ELISA. We raised two antibodies against hAGT: a mouse monoclonal antibody and a rabbit polyclonal antibody. The standard curve of this ELISA exhibited a high linearity (0.31–20 ng/ml). The correlation coefficient was >0.99. Plasma angiotensinogen concentrations of healthy volunteers ranged from 28 to 71 μg/ml ( n = 10). The ratio of UAGTto urinary creatinine concentration ranged from 5.0 to 30 μg/g ( n = 7). Intra- and interassay coefficients of variation ranged from 4.4 to 5.5% and from 4.3 to 7.0%, respectively. This ELISA system had no cross-reactivity with major proteins in proteinuric urine samples, such as human albumin, immunoglobulin, or transferrin. Moreover, the cross-reactivity of the system with angiotensin peptides was also negligible. This hAGT ELISA will be a useful tool to investigate the relationship of UAGTand reactivity to antihypertensive drugs in hypertensive patients.
Short-term intermittent hypoxia enhances sympathetic responses to continuous hypoxia in humans
Authors: Leuenberger Urs A. , Hogeman Cynthia S. , Quraishi Sadeq , Linton-Frazier Latoya , Gray Kristen S.
Published: June 2007

Short-term intermittent hypoxia leads to sustained sympathetic activation and a small increase in blood pressure in healthy humans. Because obstructive sleep apnea, a condition associated with intermittent hypoxia, is accompanied by elevated sympathetic activity and enhanced sympathetic chemoreflex responses to acute hypoxia, we sought to determine whether intermittent hypoxia also enhances chemoreflex activity in healthy humans. To this end, we measured the responses of muscle sympathetic nerve activity (MSNA, peroneal microneurography) to arterial chemoreflex stimulation and deactivation before and following exposure to a paradigm of repetitive hypoxic apnea (20 s/min for 30 min; O2 saturation nadir 81.4 ± 0.9%). Compared with baseline, repetitive hypoxic apnea increased MSNA from 113 ± 11 to 159 ± 21 units/min ( P = 0.001) and mean blood pressure from 92.1 ± 2.9 to 95.5 ± 2.9 mmHg ( P = 0.01; n = 19). Furthermore, compared with before, following intermittent hypoxia the MSNA (units/min) responses to acute hypoxia [fraction of inspired O2 (FiO2) 0.1, for 5 min] were enhanced (pre- vs. post-intermittent hypoxia: +16 ± 4 vs. +49 ± 10%; P = 0.02; n = 11), whereas the responses to hyperoxia (FiO2 0.5, for 5 min) were not changed significantly ( P = NS; n = 8). Thus 30 min of intermittent hypoxia is capable of increasing sympathetic activity and sensitizing the sympathetic reflex responses to hypoxia in normal humans. Enhanced sympathetic chemoreflex activity induced by intermittent hypoxia may contribute to altered neurocirculatory control and adverse cardiovascular consequences in sleep apnea.
Differential Effects of SNAP-25 Deletion on Ca2+-Dependent and Ca2+-Independent Neurotransmission
Authors: Bronk Peter , Deák Ferenc , Wilson Michael C. , Liu Xinran , Südhof Thomas C. , Kavalali Ege T.
Published: June 2007

At the synapse, SNAP-25, along with syntaxin/HPC-1 and synaptobrevin/VAMP, forms SNARE N-ethylmaleimide-sensitive factor [soluble (NSF) attachment protein receptor] complexes that are thought to catalyze membrane fusion. Results from neuronal cultures of synaptobrevin-2 knockout (KO) mice showed that loss of synaptobrevin has a more severe effect on calcium-evoked release than on spontaneous release or on release evoked by hypertonicity. In this study, we recorded neurotransmitter release from neuronal cultures of SNAP-25 KO mice to determine whether they share this property. In neurons lacking SNAP-25, as those deficient in synaptobrevin-2, we found that ∼10–12% of calcium-independent excitatory and inhibitory neurotransmitter release persisted. However, in contrast to synaptobrevin-2 knockouts, this remaining readily releasable pool in SNAP-25-deficient synapses was virtually insensitive to calcium-dependent–evoked stimulation. Although field stimulation reliably evoked neurotransmitter release in synaptobrevin-2 KO neurons, responses were rare in neurons lacking SNAP-25, and unlike synaptobrevin-2–deficient synapses, SNAP-25–deficient synapses did not exhibit facilitation of release during high-frequency stimulation. This severe loss of evoked exocytosis was matched by a reduction, but not a complete loss, of endocytosis during evoked stimulation. Moreover, synaptic vesicle turnover probed by FM-dye uptake and release during hypertonic stimulation was relatively unaffected by the absence of SNAP-25. This last difference indicates that in contrast to synaptobrevin, SNAP-25 does not directly function in endocytosis. Together, these results suggest that SNAP-25 has a more significant role in calcium-secretion coupling than synaptobrevin-2.
Retinogeniculate Transmission in Wakefulness
Authors: Weyand Theodore G.
Published: June 2007

Despite popular belief that the primary function of the thalamus is to “gate” sensory inputs by state, few studies have attempted to directly characterize the efficacy of such gating in the awake, behaving animal. I measured the efficacy of retinogeniculate transmission in the awake cat by taking advantage of the fact that many neurons in the lateral geniculate nucleus (LGN) are dominated by a single retinal input, and that this input produces a distinct event known as the S-potential. Retinal input failed to produce an LGN action potential half of the time. However, success or failure was powerfully tied to the recency of the S-potential. Short intervals tend to be successful and long intervals unsuccessful. For four of 12 neurons, the probability that a given S-potential could cause a spike exceeded 90% if that S-potential was preceded by an S-potential within the previous 10 ms (100 Hz). Whereas this temporal influence on efficacy has been demonstrated extensively in anesthetized animals, wakefulness is different in several ways. Overall efficacy is better in wakefulness than in anesthesia, the durations of facilitating effects are briefer in wakefulness, efficacy of long intervals is superior in wakefulness, and the temporal dependence can be briefly disrupted by altering background illumination. The last two observations may be particularly significant. Increased success at long intervals in wakefulness provides additional evidence that the spike code of the anesthetized animal is not the spike code of the awake animal. Altering retinogeniculate efficacy by altering visual conditions undermines the influence inter-S-potential interval might have in determining efficacy in the real world. Finally, S-potential amplitude, duration, and even slope are dynamic and systematic within wakefulness; providing further support that the S-potential is the extracellular signature of the retinal EPSP.