bluuebunny/crossref_metadata_2025 huggingface dataset:
Opportunities to work at home in the context of work‐life balance
Authors: Felstead Alan , Jewson Nick , Phizacklea Annie , Walters Sally
Published: August 2006

Discussion of ‘work‐life balance’ and ‘family‐friendly’ employment is much in vogue among politicians and business leaders. Often, but not always, working at home is included within such practices. However, the concepts of work‐life balance and family‐friendly are commonly left ill‐defined by researchers and policymakers alike. In this article we outline formal definitions of these terms, which place spatial issues ‐ and hence working at home ‐ at the heart of the debate. This leads us on to examine working at home through the theoretical lens offered by attempts to explain the rise of work‐life balance arrangements. Twelve hypotheses emerge from the literature and are tested on the management data contained in the 1998 Workplace Employee Relations Survey or WERS98. Many of these hypotheses pass weak statistical tests but fail on stronger logistic regression tests. The article shows that the option to work at home is more likely to be available in the public sector, large establishments and work environments in which individuals are responsible for the quality of their own output. These workplaces are typically less unionised but not especially feminised.
Knowledge management practice in Scottish law firms
Authors: Hunter Laurie , Beaumont Phil , Lee Matthew
Published: August 2006

Law firms, as part of the professional services sector, are increasingly engaged in strategic thinking about business growth and development. The management of partners, staff and their knowledge is critical to this strategic development. This study of a sample of Scottish law firms engaged in commercial and corporate law finds that organisations are at different stages of progress, and that change has focused more on technical solutions than on organisational and HR issues. Based on evidence from partners and management, and on attitude data from salaried staff, the article suggests that, although the traditional professional firm's interest in building and leveraging its human capital is still present, the underlying social and cultural processes involving motivation, sharing of experiences, coaching and mentoring are relatively underdeveloped. The implications for HR strategy and practice, and for the role of the HR manager, are considered.
A female ghetto? Women's careers in call centres
Authors: Belt Vicki
Published: August 2006

Although several studies have shown that women make up the majority of the call centre workforce, their role and position in this new and expanding industry has not yet been examined. This article makes a contribution to the research gap by exploring the extent and nature of the career opportunities open to women within call centres. Current portrayals of call centre work appear to indicate that these new workplaces offer very little in the way of either job satisfaction or potential for career progression. Indeed, on the basis of existing research evidence it could be concluded that call centres represent little more than female job ‘ghettos’. The article assesses this claim by drawing on women's own accounts of their work experiences and their perceptions of their prospects.
The rise of the ‘network organisation’ and the decline of discretion
Authors: Grugulis Irena , Vincent Steven , Hebson Gail
Published: August 2006

This article explores the implications of ‘networked’ and ‘flexible’ organisations for the work and skills of professionals/ Drawing on material from four different case studies, it reviews work that is outsourced (involving IT professionals and housing benefit caseworkers), work that is done by teachers contracted to a temporary employment agency and work organised through an inter‐firm network (chemical production workers). In each case work that was outsourced was managed very differently to that undertaken in‐house, with managerial monitoring replacing and reducing employees' discretion. New staff in these networks had fewer skills when hired and were given access to a narrower range of skills than their predecessors. By contrast, the production staff directly employed on permanent contracts in the inter‐firm network were given (and took) significant amounts of responsibility, with positive results for both their skills and the work processed. Yet, despite the negative impact they have on skills, outsourcing and subcontracting are a far more common means of securing flexibility than organisational collaboration.
The implications of the national minimum wage for training in small firms
Authors: Heyes Jason , Gray Alex
Published: August 2006

This article investigates the extent to which small firms' training practices have altered since the introduction of the national minimum wage (NMW). Low pay is particularly widespread among small firms and they are thus likely to have been disproportionately affected by the NMW. Drawing on survey data collected from 258 establishments, the study provides information about training practices and identifies the steps that employers have taken to offset the impact of the NMW. The study also assesses the extent to which firms have made use of lower ‘development’ rates for young workers and new adult recruits, and whether this has been associated with an increase in training activity. The findings suggest that the NMW has provided a positive boost to training in some cases, although this has primarily come about as a result of efforts by firms to offset increases in labour costs, as opposed to take‐up of the development rate.
Teamworking and change: managing the contradictions
Authors: Francis Helen
Published: August 2006

This article examines managers' experiences of introducing a team‐based work system in a manufacturing firm, and their efforts to manage this. Drawing on a social constructionist view, findings are presented that point to the plurality of ‘world views’ held among managers responsible for the delivery of change and to the socially contested nature of teamworking. Implications of these findings are pursued, including the need for change agents and human resource development (HRD) specialists to build sufficient time for review and reflection into change programmes. This is central to developing more skilled approaches to balancing inherent tensions in the employment relationship and processes of change, and in creating opportunities for more fluid and open dialogue among different groups and individuals within management in order to enhance processes of learning and understanding.
Labour scarcity and the survival of small firms: a resource‐based view of the road haulage industry
Authors: Marchington Mick , Carroll Marilyn , Boxall Peter
Published: August 2006

This article is concerned with the problem of labour scarcity in the road haulage industry and how it affects small firms. The recruitment and retention of lorry drivers is critically important for the industry because driving is no longer seen as an attractive occupation, and there are worries that there is an insufficient supply of new recruits to replace the experienced drivers who are leaving the industry. In order to investigate this issue, we make use of a modified version of the resource‐based view (RBV) of the firm, focusing on the notion that a minimum set of ‘table stakes’(HR practices) is necessary for the continued survival of small firms. Drawing on longitudinal data from seven small road haulage companies, we argue that owner‐managers have developed an astute combination of path‐dependent and socially complex networking abilities, embedded within an extensive understanding of both product and local labour markets. We conclude that the RBV needs extending to make greater allowance for different ownership goals and diversity in markets, and to consider the forces that promote similarity rather than difference among firms within an industry.
British employer resistance to trade union recognition
Authors: Gall Gregor
Published: August 2006

Following the introduction of a statutory mechanism by which trade unions can gain recognition from employers, this article examines employers' attempts in Britain to resist campaigns for union recognition and to undermine newly granted recognition agreements. Using an array of primary and secondary sources, the extent and nature of these employer activities are documented. The article develops a revised schema, following Roy (1980), to help understand and interpret these anti‐union activities. While of significance in deterring and undermining new recognition agreements, these activities are found to represent a minority current in the overall response of employers to campaigns for union recognition.
HR accounting as a measurement tool
Authors: Toulson Paul K , Dewe Philip
Published: August 2006

In tracing the history of human resource accounting, most reviewers would agree that the topic is now experiencing something of a revival. This research set out to explore why HR accounting is regarded as important, to whom it is important and its links with organisational and HR strategies. We used a survey‐questionnaire approach to gather data. A scale was developed measuring the extent to which respondents thought each item reflected their organisation's view on the importance of measuring of human resources. Component analysis revealed two reasons why measuring human resources is perceived as being important. The first illustrates the view that ‘measurement reflects the strategic and competitive importance of human resources’, while the second suggests that,‘to earn credibility, HRM must be expressed in financial terms’. Further analysis highlighted the importance of senior management and financial managers' support for measuring human resources and drew attention to what may appear to be a ‘hard view' of HRM held by HR managers in relation to why they consider this important.
Foreign firms in China: modelling HRM in a toy manufacturing corporation
Authors: Cooke Fang Lee
Published: August 2006

This article reports the study of a large, wholly foreign‐owned toy factory in China. It explores whether foreign direct investment (FDI) manufacturing firms in China inevitably operate in a Taylorist fashion, in contrast to the much praised HR model of blue chip multinational corporations (MNCs) in the country, or whether there is a ‘third way’ in which good HR practices may be adopted on the ground. The article concludes that a more nuanced approach is needed in our study of FDI companies in order to gain a fuller understanding of the institutional and cultural factors at play and of the consequent diversity in the HR and employment practices of FDI firms, instead of being trapped in a simplistic and polarising typological framework of analysis. This study is necessary in light of the growing diversity in the patterns of FDI companies operating in China in terms of their ownership structure, product market, management style and HR strategy, both for managers and for workers.
The implications of meta‐qualities for HR roles
Authors: Buckley Finian , Monks Kathy
Published: August 2006

A great deal has been written about the types of competencies that HR managers need. However, there is little known about how these might be acquired and which ones prove most valuable in carrying out HR tasks. This article provides insights into this issue from a study carried out in Ireland. The study examined HR managers' perceptions of the ways in which their competencies changed over the timespan of a management education process and the ways that they utilised these competencies within their work situations. The study suggests that the acquisition and development of ‘meta‐qualities’(Pedler et al, 1994) can be important to HR professionals in managing the complexity and ambiguity in their roles.
Organisational flexibility and HRM in the hotel industry: evidence from Australia
Authors: Knox Angela , Walsh Janet
Published: August 2006

The hotel industry is renowned for its poor pay and employment conditions and a low take‐up of HR practices. It is generally believed that the industry has relied on a lowcost, numerically flexible and disposable workforce. Recently, however, there has been debate concerning the extent to which managers in the hotel industry are embracing high commitment HRM and functionally flexible work practices. This study seeks to shed light on this question by analysing large‐scale survey and interview data on the hotel industry in Australia. While hotel workplaces in general continue to be associated with high levels of numerical and temporal flexibility and greater informality of HR policies, it was apparent that larger luxury hotels were adopting more systematic employee management techniques and strengthening their internal labour markets through functional flexibility initiatives. Such firms were also pursuing numerical and temporal flexibility strategies, although in rather different ways.
An Inexpensive Optical Absorption Experiment
Authors: Greenslade Thomas B.
Published: August 2006

This optical absorption experiment can be put together in only a few minutes with materials found in most secondary or undergraduate stockrooms. The absorption material is the partly transparent flexible anti-static plastic material used to package solid-state devices. The detector is a hand-held photographic exposure meter of the type that was in common use before the advent of point-and-shoot cameras. A graph of the intensity of the transmitted light as a function of the number of sheets of the material is a decreasing exponential. The emphasis of the experiment is on the mathematical form.
Finding the Outdoor Temperature Using a Tuning Fork and Resonance
Authors: Froehle Peter
Published: August 2006

This paper describes a simple laboratory exercise for estimating the outside temperature using a homemade sound resonance apparatus.
Baculovirus-Derived Human Immunodeficiency Virus Type 1 Virus-Like Particles Activate Dendritic Cells and Induce Ex Vivo T-Cell Responses
Authors: Buonaguro L. , Tornesello M. L. , Tagliamonte M. , Gallo R. C. , Wang L. X. , Kamin-Lewis R. , Abdelwahab S. , Lewis G. K. , Buonaguro F. M.
Published: August 2006

We have recently developed a candidate human immunodeficiency virus type 1 (HIV-1) vaccine model based on HIV-1 Pr55

gag

virus-like particles (HIV-VLPs), produced in a baculovirus expression system and presenting a gp120 molecule from a Ugandan HIV-1 isolate of clade A (HIV-VLP
A
s). The HIV-VLP
A
s show the induction in BALB/c mice of systemic and mucosal neutralizing antibodies as well as cytotoxic T lymphocytes, by intraperitoneal as well as intranasal administration. In the present article, the effects of the baculovirus-expressed HIV-VLPs on human immature monocyte-derived dendritic cells (MDDCs) have been evaluated. The HIV-VLPs efficiently induce maturation and activation of MDDCs and are incorporated into MDDCs preferentially via an actin-dependent macropinocytosis and endocytosis. The HIV-VLP-activated MDDCs show enhanced Th1- and Th2-specific cytokine production, and the effects of HIV-VLPs on MDDCs are not mediated through Toll-like receptors 2 and 4 (TLR2 and -4) signaling. Finally, HIV-VLP-loaded MDDCs are able to induce a primary and secondary response in autologous human CD4
+
T cells in an ex vivo immunization assay. Our results on the interaction and processing of baculovirus HIV-VLPs by MDDCs give an insight into the mechanisms underlying the immune response induced by HIV-VLP
A
s in vivo.
DC-SIGN and CLEC-2 Mediate Human Immunodeficiency Virus Type 1 Capture by Platelets
Authors: Chaipan Chawaree , Soilleux Elizabeth J. , Simpson Peter , Hofmann Heike , Gramberg Thomas , Marzi Andrea , Geier Martina , Stewart Elizabeth A. , Eisemann Jutta , Steinkasserer Alexander , Suzuki-Inoue Katsue , Fuller Gemma L. , Pearce Andrew C. , Watson Steve P. , Hoxie James A. , Baribaud Frederic , Pöhlmann Stefan
Published: August 2006

Platelets can engulf human immunodeficiency virus type 1 (HIV-1), and a significant amount of HIV-1 in the blood of infected individuals is associated with these cells. However, it is unclear how platelets capture HIV-1 and whether platelet-associated virus remains infectious. DC-SIGN and other lectins contribute to capture of HIV-1 by dendritic cells (DCs) and facilitate HIV-1 spread in DC/T-cell cocultures. Here, we show that platelets express both the C-type lectin-like receptor 2 (CLEC-2) and low levels of DC-SIGN. CLEC-2 bound to HIV-1, irrespective of the presence of the viral envelope protein, and facilitated HIV-1 capture by platelets. However, a substantial fraction of the HIV-1 binding activity of platelets was dependent on DC-SIGN. A combination of DC-SIGN and CLEC-2 inhibitors strongly reduced HIV-1 association with platelets, indicating that these lectins are required for efficient HIV-1 binding to platelets. Captured HIV-1 was maintained in an infectious state over several days, suggesting that HIV-1 can escape degradation by platelets and might use these cells to promote its spread. Our results identify CLEC-2 as a novel HIV-1 attachment factor and provide evidence that platelets capture and transfer infectious HIV-1 via DC-SIGN and CLEC-2, thereby possibly facilitating HIV-1 dissemination in infected patients.
Gene-Specific Inhibition of Reovirus Replication by RNA Interference
Authors: Kobayashi Takeshi , Chappell James D. , Danthi Pranav , Dermody Terence S.
Published: August 2006

Mammalian reoviruses contain a genome of 10 segments of double-stranded RNA (dsRNA). Reovirus replication and assembly occur within distinct structures called viral inclusions, which form in the cytoplasm of infected cells. Viral nonstructural proteins μNS and σNS and core protein μ2 play key roles in forming viral inclusions and recruiting other viral proteins and RNA to these structures for replication and assembly. However, the precise functions of these proteins in viral replication are poorly defined. Therefore, to better understand the functions of reovirus proteins associated with formation of viral inclusions, we used plasmid-based vectors to establish 293T cell lines stably expressing small interfering RNAs (siRNAs) specific for transcripts encoding the μ2, μNS, and σNS proteins of strain type 3 Dearing (T3D). Infectivity assays revealed that yields of T3D, but not those of strain type 1 Lang, were significantly decreased in 293T cells stably expressing μ2, μNS, or σNS siRNA. Stable expression of siRNAs specific for any one of these proteins substantially diminished viral dsRNA, protein synthesis, and inclusion formation, indicating that each is a critical component of the viral replication machinery. Using cell lines stably expressing μNS siRNA, we developed a complementation system to rescue viral replication by transient transfection with recombinant T3D μNS in which silent mutations were introduced into the sequence targeted by the μNS siRNA. Furthermore, we demonstrated that μNSC, which lacks the first 40 amino residues of μNS, is incapable of restoring reovirus growth in the complementation system. These results reveal interdependent functions for viral inclusion proteins and indicate that cell lines stably expressing reovirus siRNAs are useful tools for the study of viral protein structure-function relationships.
CD80 and CD86 Control Antiviral CD8
+
T-Cell Function and Immune Surveillance of Murine Gammaherpesvirus 68
Authors: Fuse Shinichiro , Obar Joshua J. , Bellfy Sarah , Leung Erica K. , Zhang Weijun , Usherwood Edward J.
Published: August 2006

The interactions between CD80 and CD86 on antigen-presenting cells and CD28 on T cells serve as an important costimulatory signal in the activation of T cells. Although the simplistic two-signal hypothesis has been challenged in recent years by the identification of different costimulators, this classical pathway has been shown to significantly impact antiviral humoral and cellular immune responses. How the CD80/CD86-CD28 pathway affects the control of chronic or latent infections has been less well characterized. In this study, we investigated its role in antiviral immune responses against murine gammaherpesvirus 68 (MHV-68) and immune surveillance using CD80/CD86
−/−
mice. In the absence of CD80/CD86, primary antiviral CD8
+
T-cell responses and the induction of neutralizing antibodies were severely impaired. During long-term immune surveillance, the virus-specific CD8
+
T cells were impaired in IFN-γ production and secondary expansion and exhibited an altered phenotype. Surprisingly, a low level of viral reactivation in the lung was observed, and this effect was independent of CD28 and CTLA-4. Thus, CD80 and CD86, signaling through CD28 and possibly another unidentified receptor, are required for optimal immune surveillance and antiviral immune responses to murine gammaherpesvirus.
Rotavirus Nonstructural Protein NSP3 Is Not Required for Viral Protein Synthesis
Authors: Montero Hilda , Arias Carlos F. , Lopez Susana
Published: August 2006

Initiation is the rate-limiting step in protein synthesis and therefore an important target for regulation. For the initiation of translation of most cellular mRNAs, the cap structure at the 5′ end is bound by the translation factor eukaryotic initiation factor 4E (eIF4E), while the poly(A) tail, at the 3′ end, is recognized by the poly(A)-binding protein (PABP). eIF4G is a scaffold protein that brings together eIF4E and PABP, causing the circularization of the mRNA that is thought to be important for an efficient initiation of translation. Early in infection, rotaviruses take over the host translation machinery, causing a severe shutoff of cell protein synthesis. Rotavirus mRNAs lack a poly(A) tail but have instead a consensus sequence at their 3′ ends that is bound by the viral nonstructural protein NSP3, which also interacts with eIF4GI, using the same region employed by PABP. It is widely believed that these interactions lead to the translation of rotaviral mRNAs, impairing at the same time the translation of cellular mRNAs. In this work, the expression of NSP3 in infected cells was knocked down using RNA interference. Unexpectedly, under these conditions the synthesis of viral proteins was not decreased, while the cellular protein synthesis was restored. Also, the yield of viral progeny increased, which correlated with an increased synthesis of viral RNA. Silencing the expression of eIF4GI further confirmed that the interaction between eIF4GI and NSP3 is not required for viral protein synthesis. These results indicate that NSP3 is neither required for the translation of viral mRNAs nor essential for virus replication in cell culture.
Novel Function of Prothymosin Alpha as a Potent Inhibitor of Human Immunodeficiency Virus Type 1 Gene Expression in Primary Macrophages
Authors: Mosoian Arevik , Teixeira Avelino , High Anthony A. , Christian Robert E. , Hunt Donald F. , Shabanowitz Jeffrey , Liu Xinyan , Klotman Mary
Published: August 2006

CD8
+
T lymphocytes control human immunodeficiency virus type 1 (HIV-1) infection by a cytotoxic major histocompatibility complex-restricted pathway as well as by secretion of noncytotoxic soluble inhibitory factors. Several components of CD8
+
cell supernatants have been identified that contribute to the latter activity. In this study we report that prothymosin alpha (ProTα), a protein found in the cell culture medium of the herpesvirus saimiri-transformed CD8
+
T-cell line, K#1 50K, has potent HIV-1-inhibitory activity. Depletion of native ProTα from an HIV-1-inhibitory fraction of CD8
+
cell supernatants removes the inhibitory activity, supporting its role in inhibition via soluble mediators. ProTα is an abundant, acidic peptide that has been reported to be localized in the nucleus and associated with cell proliferation and activation of transcription. In this report we demonstrate that ProTα suppresses HIV-1 replication, its activity is target cell specific, and inhibition occurs following viral integration. Native and recombinant ProTα protein potently inhibit HIV-1 long terminal repeat (LTR)-driven gene expression in macrophages. Furthermore studies using different promoters in lentiviral vectors (cytomegalovirus and phosphoglycerate kinase) revealed that suppression of viral replication by ProTα is not HIV LTR specific.
High-Throughput, Library-Based Selection of a Murine Leukemia Virus Variant To Infect Nondividing Cells
Authors: Yu Julie H. , Schaffer David V.
Published: August 2006

Gammaretroviruses, such as murine leukemia virus (MLV), are functionally distinguished from lentiviruses, such as human immunodeficiency virus, by their inability to infect nondividing cells. Attempts to engineer this property into MLV have been hindered by an incomplete understanding of early events in the viral life cycle. We utilized a transposon-based method to generate saturated peptide insertion libraries of MLV
gag-pol
variants with nuclear localization signals randomly incorporated throughout these overlapping genes. High-throughput selection of the libraries via iterative retroviral infection of nondividing cells led to the identification of a novel variant that successfully transduced growth-arrested cells. Vector packaging by cotransfection of the
gag-pol
.
NLS
variant with wild-type
gag-pol
produced high-titer virions capable of infecting neurons in vitro and in vivo. The capacity of mutant virions to transduce nondividing cells could help to elucidate incompletely understood mechanisms of the viral life cycle and greatly broaden the gene therapy applications of retroviral vectors. Furthermore, the ability to engineer key intracellular viral infection steps has potential implications for the understanding, design, and control of other postentry events. Finally, this method of library generation and selection for a desired phenotype directly in a mammalian system can be readily expanded to address other challenges in protein engineering.
Alphavirus Capsid Protein Helix I Controls a Checkpoint in Nucleocapsid Core Assembly
Authors: Hong Eunmee M. , Perera Rushika , Kuhn Richard J.
Published: August 2006

The assembly of the alphavirus nucleocapsid core has been investigated using an in vitro assembly system. The C-terminal two-thirds of capsid protein (CP), residues 81 to 264 in Sindbis virus (SINV), have been previously shown to have all the RNA-CP and CP-CP contacts required for core assembly in vitro. Helix I, which is located in the N-terminal dispensable region of the CP, has been proposed to stabilize the core by forming a coiled coil in the CP dimer formed by the interaction of residues 81 to 264. We examined the ability of heterologous alphavirus CPs to dimerize and form phenotypically mixed core-like particles (CLPs) using an in vitro assembly system. The CPs of SINV and Ross River virus (RRV) do not form phenotypically mixed CLPs, but SINV and Western equine encephalitis virus CPs do form mixed cores. In addition, CP dimers do not form between SINV and RRV in these assembly reactions. In contrast, an N-terminal truncated SINV CP (residues 81 to 264) forms phenotypically mixed CLPs when it is assembled with full-length heterologous CPs, suggesting that the region that controls the mixing is present in the N-terminal 80 residues. Furthermore, this result suggests that the dimeric interaction, which was absent between SINV and RRV CPs, can be restored by the removal of the N-terminal 80 residues of the SINV CP. We mapped the determinant that is responsible for phenotypic mixing onto helix I by using domain swapping experiments. Thus, discrimination of the CP partner in alphavirus core assembly appears to be dependent on helix I sequence compatibility. These results suggest that helix I provides one of the important interactions during nucleocapsid core formation and may play a regulatory role during the early steps of the assembly process.
Keratinocyte-Secreted Laminin 5 Can Function as a Transient Receptor for Human Papillomaviruses by Binding Virions and Transferring Them to Adjacent Cells
Authors: Culp Timothy D. , Budgeon Lynn R. , Marinkovich M. Peter , Meneguzzi Guerrino , Christensen Neil D.
Published: August 2006

Human papillomaviruses (HPVs) replicate only in the terminally differentiating epithelium of the skin and mucosa. While infection of basal keratinocytes is considered a requirement for permissive infection, it remains unclear whether virions can specifically target basal cells for adsorption and uptake following epithelial wounding. We present evidence that HPV binds specifically to laminin 5 (LN5), a component of the extracellular matrix (ECM) secreted by migrating and basal keratinocytes. HPV type 11 capsids colocalized with LN5 in the ECM secreted by vaginal keratinocytes. Binding of both virions and virus-like particles to purified LN5 and to the LN5-rich ECM secreted by cultured keratinocytes was effectively blocked by pretreatment with anti-LN5 antibodies. HPV capsid binding to human cervical mucosa sections included the basement membrane which contains LN5. Cultured keratinocytes expressing α6 integrin, a transmembrane protein known to bind LN5, were readily infected by virions preadsorbed to LN5-containing substrates, whereas mutant keratinocytes lacking α6 integrin were relatively resistant to infection via this route. These findings suggest a model of natural HPV infection in which proliferating keratinocytes expressing α6 integrin at the site of epithelial wounding might be targeted by virions adsorbed transiently to LN5 secreted by migrating keratinocytes.
Envelope Proteins of Jaagsiekte Sheep Retrovirus and Enzootic Nasal Tumor Virus Induce Similar Bronchioalveolar Tumors in Lungs of Mice
Authors: Wootton Sarah K. , Halbert Christine L. , Miller A. Dusty
Published: August 2006

Jaagsiekte sheep retrovirus (JSRV) induces bronchioalveolar tumors in sheep and goats. Expression of the JSRV envelope (Env) protein in mouse airway epithelial cells induces similar tumors, indicating that Env expression is sufficient for tissue-specific tumor formation. Enzootic nasal tumor virus (ENTV) is related to JSRV but induces tumors in the nasal epithelium of sheep and goats. Here we found that ENTV Env can also induce tumors in mice but, unexpectedly, with a phenotype identical to that of tumors induced by the JSRV Env, indicating that factors other than Env mediate the tissue specificity of tumor induction by ENTV.
Vaginal Protection and Immunity after Oral Immunization of Mice with a Novel Vaccine Strain ofListeria monocytogenesExpressing Human Immunodeficiency Virus Type 1gag
Authors: Zhao Xinyan , Zhang Manxin , Li Zhongxia , Frankel Fred R.
Published: August 2006

Natural transmission of human immunodeficiency virus (HIV) occurs at mucosal surfaces. During acute infection, intestinal and other mucosae are preferential sites of virus replication and rapidly become depleted of CD4+T cells. Therefore, mucosal immunity may be critical to control both initial infection and the massive early spread of virus. An attenuatedd-alanine-requiring strain of the oral intracellular microorganismListeria monocytogenesexpressing HIV type 1gagwas shown to induce protective cell-mediated immunity in mice against viruses that express HIVgagwhen immunization occurs in the presence of a transient supply ofd-alanine. In this study, we examined the efficacy of new attenuated strains that are able to synthesized-alanine from a heterologousdalgene tightly regulated by anactA-promoted resolvase recombination system. In the absence ofd-alanine, Gag-specific cytotoxic T lymphocytes (CTLs) were induced systemically after intravenous immunization, and one strain, Lmdd-gag/pARS, induced strong dose-dependent Gag-specific CTLs after oral immunization. A significant level of Gag-specific CD8+T cells was induced in the mucosal-associated lymphoid tissues (MALTs). Upon intravaginal challenge of these orally immunized mice with recombinant vaccinia virus (rVV) expressing HIVgag, gamma interferon- and tumor necrosis factor alpha-secreting Gag-specific CD8+T cells were dramatically increased in the spleen and MALTs. Oral immunization with Lmdd-gag/pARS led to complete protection against vaginal challenge by a homologous clade Bgag-expressing rVV. In addition, strong cross-clade protection was seen against clades A and C and partial protection against clade Ggag-expressing rVV. These results suggest that Lmdd-gag/pARS may be considered as a novel vaccine candidate for use against HIV/AIDS.
α2,3 and α2,6 N-Linked Sialic Acids Facilitate Efficient Binding and Transduction by Adeno-Associated Virus Types 1 and 6
Authors: Wu Zhijian , Miller Edward , Agbandje-McKenna Mavis , Samulski Richard Jude
Published: August 2006

Recombinant adeno-associated viruses (AAVs) are promising vectors in the field of gene therapy. Different AAV serotypes display distinct tissue tropism, believed to be related to the distribution of their receptors on target cells. Of the 11 well-characterized AAV serotypes, heparan sulfate proteoglycan and sialic acid have been suggested to be the attachment receptors for AAV type 2 and types 4 and 5, respectively. In this report, we identify the receptor for the two closely related serotypes, AAV1 and AAV6. First, we demonstrate using coinfection experiments and luciferase reporter analysis that AAV1 and AAV6 compete for similar receptors. Unlike heparin sulfate, enzymatic or genetic removal of sialic acid markedly reduced AAV1 and AAV6 binding and transduction. Further analysis using lectin staining and lectin competition assays identified that AAV1 and AAV6 use either α2,3-linked or α2,6-linked sialic acid when transducing numerous cell types (HepG2, Pro-5, and Cos-7). Treatment of cells with proteinase K but not glycolipid inhibitor reduced AAV1 and AAV6 infection, supporting the hypothesis that the sialic acid that facilitates infection is associated with glycoproteins rather than glycolipids. In addition, we determined by inhibitor (
N
-benzyl GalNAc)- and cell line-specific (Lec-1) studies that AAV1 and AAV6 require N-linked and not O-linked sialic acid. Furthermore, a resialylation experiment on a deficient Lec-2 cell line confirmed a 2,3 and 2,6 N-linked sialic acid requirement, while studies of mucin with O-linked sialic acid showed no inhibition effect for AAV1 and AAV6 transduction on Cos-7 cells. Finally, using a glycan array binding assay we determined that AAV1 efficiently binds to NeuAcα2-3GalNAcβ1-4GlcNAc, as well as two glycoproteins with α2,3 and α2,6 N-linked sialic acids. Taken together, competition, genetic, inhibitor, enzymatic reconstitution, and glycan array experiments support α2,3 and α2,6 sialic acids that are present on N-linked glycoproteins as primary receptors for efficient AAV1 and AAV6 viral infection.
Temporal Transcription Program of Recombinant
Autographa californica
Multiple Nucleopolyhedrosis Virus
Authors: Jiang Shih Sheng , Chang I-Shou , Huang Lin-Wei , Chen Po-Cheng , Wen Chi-Chung , Liu Shu-Chen , Chien Li-Chu , Lin Chung-Yen , Hsiung Chao A. , Juang Jyh-Lyh
Published: August 2006

Baculoviruses, a family of large, rod-shaped viruses that mainly infect lepidopteran insects, have been widely used to transduce various cells for exogenous gene expression. Nonetheless, how a virus controls its transcription program in cells is poorly understood. With a custom-made baculovirus DNA microarray, we investigated the recombinant
Autographa californica
multiple nucleopolyhedrosis virus (Ac
M
NPV) gene expression program in lepidopteran Sf21 cells over the time course of infection. Our analysis of transcription kinetics in the cells uncovered sequential viral gene expression patterns possibly regulated by different mechanisms during different phases of infection. To gain further insight into the regulatory network, we investigated the transcription program of a mutant virus deficient in an early transactivator (
pe38
) and uncovered several
pe38
-dependent and
pe38
-independent genes. This study of baculovirus dynamic transcription programs in different virus genetic backgrounds provides new molecular insights into how gene expression in viruses is regulated.
Inhibiting Hypoxia-Inducible Factor 1 for Cancer Therapy
Authors: Melillo Giovanni
Published: August 2006

Hypoxia has long been recognized as a common feature of solid tumors and a negative prognostic factor for response to treatment and survival of cancer patients. The discovery of hypoxia-inducible factor 1 (HIF-1), a molecular determinant of the response of mammalian cells to hypoxia, has led to the identification of a “molecular target” of hypoxia suitable for the development of cancer therapeutics. Early controversy about whether or not HIF-1 is a good target for therapy has not discouraged academic groups and pharmaceutical companies from actively engaging in the discovery of small-molecule inhibitors of HIF. However, what is the best strategy to inhibit HIF and how HIF inhibitors should be developed for treatment of human cancers is still poorly defined. In this review, aspects related to the identification and early development of novel HIF inhibitors are discussed. Identification and validation of pharmacodynamic end points relevant to the HIF-1 pathway is essential for a rational development of HIF inhibitors. Integration of these biomarkers in early clinical trials may provide valuable information to determine the contribution of HIF inhibitors to response to therapy. Finally, HIF inhibitors should be incorporated in combination strategies to effectively target multiple cellular components of the tumor microenvironment and redundant signaling pathways frequently deregulated in human cancer. (Mol Cancer Res 2006;4(9):601–5)
Ovariectomy Augments Hypertension Through Rho-Kinase Activation in the Brain Stem in Female Spontaneously Hypertensive Rats
Authors: Ito Koji , Hirooka Yoshitaka , Kimura Yoshikuni , Sagara Yoji , Sunagawa Kenji
Published: August 2006

Estrogen protects against increases in arterial pressure (AP) by acting on blood vessels and on cardiovascular centers in the brain. The mechanisms underlying the effects of estrogen in the brain stem, however, are not clear. The aim of the present study was to determine whether ovariectomy affects AP via the Rho/Rho-kinase pathway in the brain stem. We performed bilateral ovariectomy in 12-week-old female spontaneously hypertensive rats. AP and heart rate (HR), measured using radiotelemetry in awake rats, were increased in ovariectomized rats compared with control rats (mean AP: 163±3 versus 144±4 mm Hg; HR: 455±4 versus 380±6 bpm). Continuous intracisternal infusion of Y-27632 significantly attenuated the ovariectomy-induced increase in AP and HR (mean AP: 137±6 versus 163±3 mm Hg; HR: 379±10 versus 455±4 bpm). In addition, we confirmed the increase of Rho-kinase activity in the brain stem in ovariectomized rats, and the increase was attenuated by intracisternal infusion of Y-27632 via the phosphorylated ezrin, radixin, and moesin (ERM) family, which are Rho-kinase target proteins. Furthermore, angiotensin II type 1 receptor expression in the brain stem was significantly greater in ovariectomized rats than in control rats, and the increase was partially reduced by intracisternal infusion of Y-27632. In a separate group of animals, we confirmed that the serum and cerebrospinal fluid 17β-estradiol concentrations decreased in ovariectomized rats. These results suggest that depletion of endogenous estrogen by ovariectomy, at least in part, induces hypertension in female spontaneously hypertensive rats via activation of the renin–angiotensin system and the Rho/Rho-kinase pathway in the brain stem.
Endothelial NO Synthase Activity in Nucleus Tractus Solitarii Contributes to Hypertension in Spontaneously Hypertensive Rats
Authors: Waki Hidefumi , Murphy David , Yao Song T. , Kasparov Sergey , Paton Julian F.R.
Published: August 2006

NO is implicated as a major modulator of central nervous circuits regulating cardiovascular activity. Based on previous data, we hypothesized that overactivity of endothelial NO synthase (eNOS) within the nucleus tractus solitarii (NTS) could contribute to the hypertension in the spontaneously hypertensive rat (SHR). Using real-time PCR, we found that endogenous eNOS mRNA was greater in the NTS of mature, but not juvenile prehypertensive SHRs compared with aged-matched Wistar Kyoto (WKY) rats. To test the functional significance of this, we chronically blocked eNOS activity in the NTS in the adult SHR by in vivo adenoviral-mediated gene transfer of a dominant-negative form of eNOS; data were compared with WKY rats. This resulted in a fall in arterial pressure in the SHR but not WKY rats. In both rat strains, cardiac baroreceptor reflex gain and the high-frequency spectral component of heart rate variability increased. Thus, endogenous eNOS activity in the NTS plays a major role in determining the set point of arterial pressure in the SHR and contributes to maintaining high arterial blood pressure in this animal model of human hypertension.
Quantification of Wave Reflection in the Human Aorta From Pressure Alone
Authors: Westerhof Berend E. , Guelen Ilja , Westerhof Nico , Karemaker John M. , Avolio Alberto
Published: August 2006

Wave reflections affect the proximal aortic pressure and flow waves and play a role in systolic hypertension. A measure of wave reflection, receiving much attention, is the augmentation index (AI), the ratio of the secondary rise in pressure and pulse pressure. AI can be limiting, because it depends not only on the magnitude of wave reflection but also on wave shapes and timing of incident and reflected waves. More accurate measures are obtainable after separation of pressure in its forward (P
f
) and reflected (P
b
) components. However, this calculation requires measurement of aortic flow. We explore the possibility of replacing the unknown flow by a triangular wave, with duration equal to ejection time, and peak flow at the inflection point of pressure (F
tIP
) and, for a second analysis, at 30% of ejection time (F
t30
). Wave form analysis gave forward and backward pressure waves. Reflection magnitude (RM) and reflection index (RI) were defined as RM=P
b
/P
f
and RI=P
b
/(P
f
+P
b
), respectively. Healthy subjects, including interventions such as exercise and Valsalva maneuvers, and patients with ischemic heart disease and failure were analyzed. RMs and RIs using F
tIP
and F
t30
were compared with those using measured flow (F
m
). Pressure and flow were recorded with high fidelity pressure and velocity sensors. Relations are: RM
tIP
=0.82RM
mf
+0.06 (
R
2
=0.79; n=24), RM
t30
=0.79RM
mf
+0.08 (
R
2
=0.85; n=29) and RI
tIP
=0.89RI
mf
+0.02 (
R
2
=0.81; n=24), RI
t30
=0.83RI
mf
+0.05 (
R
2
=0.88; n=29). We suggest that wave reflection can be derived from uncalibrated aortic pressure alone, even when no clear inflection point is distinguishable and AI cannot be obtained. Epidemiological studies should establish its clinical value.
Nebivolol Inhibits Superoxide Formation by NADPH Oxidase and Endothelial Dysfunction in Angiotensin II–Treated Rats
Authors: Oelze Matthias , Daiber Andreas , Brandes Ralf P. , Hortmann Marcus , Wenzel Philip , Hink Ulrich , Schulz Eberhard , Mollnau Hanke , von Sandersleben Alexandra , Kleschyov Andrei L. , Mülsch Alexander , Li Huige , Förstermann Ulrich , Münzel Thomas
Published: August 2006

Nebivolol is a β
1
-receptor antagonist with vasodilator and antioxidant properties. Because the vascular NADPH oxidase is an important superoxide source, we studied the effect of nebivolol on endothelial function and NADPH oxidase activity and expression in the well-characterized model of angiotensin II–induced hypertension. Angiotensin II infusion (1 mg/kg per day for 7 days) caused endothelial dysfunction in male Wistar rats and increased vascular superoxide as detected by lucigenin-derived chemiluminescence, as well as dihydroethidine staining. Vascular NADPH oxidase activity, as well as expression at the mRNA and protein level, were markedly upregulated, as well as NOS III uncoupled, as evidenced by NO synthase III inhibitor experiments and dihydroethidine staining and by markedly decreased hemoglobin–NO concentrations. Treatment with the β-receptor blocker nebivolol but not metoprolol (10 mg/kg per day for each drug) normalized endothelial function, reduced superoxide formation, increased NO bioavailability, and inhibited upregulation of the activity and expression of the vascular NADPH oxidase, as well as membrane association of NADPH oxidase subunits (Rac1 and p67
phox
). In addition, NOS III uncoupling was prevented. In vitro treatment with nebivolol but not atenolol or metoprolol induced a dissociation of p67
phox
and Rac1, as well as an inhibition of NADPH oxidase activity assessed in heart membranes from angiotensin II–infused animals, as well as in homogenates of Nox1 and cytosolic subunit–transfected and phorbol ester–stimulated HEK293 cells. These findings indicate that nebivolol interferes with the assembly of NADPH oxidase. Thus, inhibitory effects of this β-blocker on vascular NADPH oxidase may explain, at least in part, its beneficial effect on endothelial function in angiotensin II–induced hypertension.
Aging Reduces the Efficacy of Estrogen Substitution to Attenuate Cardiac Hypertrophy in Female Spontaneously Hypertensive Rats
Authors: Jazbutyte Virginija , Hu Kai , Kruchten Patricia , Bey Emmanuel , Maier Sebastian K.G. , Fritzemeier Karl-Heinrich , Prelle Katja , Hegele-Hartung Christa , Hartmann Rolf W. , Neyses Ludwig , Ertl Georg , Pelzer Theo
Published: August 2006

Clinical trials failed to show a beneficial effect of postmenopausal hormone replacement therapy, whereas experimental studies in young animals reported a protective function of estrogen replacement in cardiovascular disease. Because these diverging results could in part be explained by aging effects, we compared the efficacy of estrogen substitution to modulate cardiac hypertrophy and cardiac gene expression among young (age 3 months) and senescent (age 24 months) spontaneously hypertensive rats (SHRs), which were sham operated or ovariectomized and injected with placebo or identical doses of 17β-estradiol (E2; 2 μg/kg body weight per day) for 6 weeks (n=10/group). Blood pressure was comparable among sham-operated senescent and young SHRs and not altered by ovariectomy or E2 treatment among young or among senescent rats. Estrogen substitution inhibited uterus atrophy and gain of body weight in young and senescent ovariectomized SHRs, but cardiac hypertrophy was attenuated only in young rats. Cardiac estrogen receptor-α expression was lower in intact and in ovariectomized senescent compared with young SHRs and increased with estradiol substitution in aged rats. Plasma estradiol and estrone levels were lower not only in sham-operated but surprisingly also in E2-substituted senescent SHRs and associated with a reduction of hepatic 17β-hydroxysteroid dehydrogenase type 1 enzyme activity, which converts weak (ie, estrone) into potent estrogens, such as E2. Aging attenuates the antihypertrophic effect of estradiol in female SHRs and is associated with profound alterations in cardiac estrogen receptor-α expression and estradiol metabolism. These observations contribute to explain the lower efficiency of estrogen substitution in senescent SHRs.