bluuebunny/crossref_metadata_2025 huggingface dataset:
Perceived diversity and organizational performance
Authors: Allen Richard S. , Dawson Gail , Wheatley Kathleen , White Charles S.
Published: December 2007

Purpose

The purpose of this paper is to investigate the relationship between employee perceptions of diversity within the senior management, management and non‐management levels of their organizations and their perceptions of organizational performance.

Design/methodology/approach

Surveys were administered to 391 managers or professionals in 130 organizations located in the southeastern United States to determine their perceptions of diversity and performance within their organizations.

Findings

Regression analysis found strong support for the hypothesis that employee perceptions of diversity at the senior management level of an organization is positively related to perceptions of organizational performance. Likewise, there was support for the hypothesis that employee perceptions of diversity at the non‐manager level were positively related to perceptions of organizational performance.

Research limitations/implications

The current study was based strictly on perceptual measures. Future research could also consider the use of more objective measures of diversity to gauge any potential differences between perception and reality. Considering that the sample was drawn strictly from the southeastern US, the conclusions may not be applicable to other cultures in other parts of the world.

Practical implications

Organizations need to be sure that they focus on initiatives that have a positive influence on employee perceptions of diversity within the ranks of senior management and non‐management.

Originality/value

This research sheds new light on the importance of employee perceptions of diversity within the various levels of employees in their organizations and organizational performance.
An evaluation of employee motivation in the extended public sector in Greece
Authors: Manolopoulos Dimitris
Published: December 2007

Purpose

The purpose of this paper is to advance the understanding of the relationship between work motivation and organisational performance in the extended public sector, by testing empirically common elements of existing theoretical frameworks.

Design/methodology/approach

A unique questionnaire‐based survey was carried out in three organisations/corporations where the state is the major stakeholder. Of the 1,000 questionnaires distributed, 454 were returned and included in the analysis. By using descriptive statistics the provision of extrinsic rewards and intrinsic motives in the extended public sector of Greece was identified.

Findings

Findings show that the public sector in Greece is more likely to provide extrinsic than intrinsic rewards, however the latter seems to be related to better organisational outcomes. Both individuals' ability and demographic characteristics are core determinants of employees' motivational preferences.

Research limitations/implications

The core of this paper tests empirically the relationship between intrinsic and extrinsic motivation with performance in a country of EU “periphery”. Caution should be exercised in generalizing the results for more advanced economies.

Practical implications

Organisational leaders and public management in Greece need to conceive work motivation as a complex system and recognize the importance of intrinsic incentives. Originality/value – There is currently limited evidence on the impact of motivation in the performance of the extended public sector. This research is one of the very few that has been made from the perspective of employees. To the extent of the author's knowledge, this is the first time that a detailed public sector level analysis on work motivation has been presented for Greece.
Two representatives but no representation: cases from Estonia
Authors: Kallaste Epp , Jaakson Krista , Eamets Raul
Published: December 2007

Purpose

The purpose of this paper is to discover how non‐unionised representatives (NERs) are created and what their role is in comparison to unionised representation. The authors aim to analyse why the institution of non‐unionised employee representation is created if its functions overlap with those of the unions, including the functions of collective bargaining and information‐consultation.

Design/methodology/approach

The case study involves interviews with representatives and executive directors, as well as a survey of the employees of two companies.

Findings

The results show that when there is a weak union, the employers initiate an NER in order to involve the whole workforce in the collective agreement. The NER is elected by employees even though it was initiated by the employer. The roles of the two representatives do not differ much, the main function for both being collective bargaining with some provision for information and consultation.

Originality/value

The unique situation in Estonia, which is about to change with adoption of EU directive 14/2002/EC, enables the analysis of cases involving two different representative institutions with the same functions in the same company. This provides valuable input for researchers describing in practice the behaviour of representatives and employers in this situation. It also provides East‐European policy makers some idea about how policies that address collective bargaining and the involvement of workers should be designed.
On document supply in Ireland and the USA: experiences at the Boole Library, Cork University
Authors: Ashton Susanna
Published: December 2007

Purpose

The purpose of this paper is to compare the Boole Library at Cork University, Ireland with university libraries in the USA in terms of resource sharing and inter‐library lending.

Design/methodology/approach

Comparisons are made between Boole Library and university libraries in the USA with reference to lack of funds and resources. The paper highlights the differences in funding of inter‐library lending.

Findings

Much could be said about how electronic resources are altering the landscape and future of interlibrary loan, but no media forms have evolved to entirely satisfy readers' need to handle the physical book in front of them.

Originality/value

One of the remarkable things about the physical book is what a superb technological form it is. Books are both portable and strong. There is still no better way to read lengthy texts. Although more people are requesting articles electronically, the demand for books seems to keep growing apace with the development of shared library catalogs.
Ten years after
Authors: Caplan Priscilla
Published: December 2007

Purpose

The purpose of this paper is to reflect on progress over the last ten years in the field of digital preservation for cultural heritage institutions.

Design/methodology/approach

This is an opinion piece, based on the experience of a practitioner in digital preservation.

Findings

Digital preservation has become a mainstream activity. There are differences in the American and European approaches to supporting and organizing preservation initiatives. US institutions would benefit from wider outreach and education efforts.

Practical implications

The implications are left to the reader, but may suggest that more reflection on the goals and strategies of the preservation community is in order.

Originality/value

This paper identifies a need to develop and support distributed centers of excellence to promote digital preservation, provide expertise to other institutions, and to organize sharing and training opportunities for their constituencies.
Heuristic evaluation of interface usability for a web‐based OPAC
Authors: Yushiana Mansor , Abdul Rani Widyawati
Published: December 2007

Purpose

The purpose of this paper is to investigate the usability of a web‐based OPAC (WebPAC) user interface at the International Islamic University Malaysia (IIUM). It also looks at the applicability of heuristic evaluation in designing a user‐centered WebPAC interface.

Design/methodology/approach

Based on Nielsen's ten usability heuristic principles, the study focuses on three heuristics only, i.e. aesthetic and minimalist design, match between interface and the real world, and visibility of interface status.

Findings

Results of the study found that the WebPAC interface conforms to at least 70 percent usability properties prescribed. Usability problems violated in the interface were identified.

Practical implications

The study suggests that heuristic evaluation is applicable in libraries to asses the usability of user interface for online catalogs.

Originality/value

Heuristic evaluation could assist libraries in designing user‐centered interface for online catalogs.
Changing markets, changing relationships
Authors: Andrews Mark
Published: December 2007

Purpose

Dissatisfaction with the online public access catalog (in particular) and the integrated library system (in general) have prompted a variety of responses from libraries and library automation vendors. The purpose of this paper is to summarize and examine these responses to get some sense of the library automation market's “trajectory.”

Design/methodology/approach

The approach is to write a discursive essay on: the “broken” online public access catalogs; a review of the literature about online catalog features, limitations and remedies; customer (library) responses; (library automation) vendor responses, including a review of recent market surveys, and an attempted meta‐analysis of some of those surveys; and an attempt to redefine the ILS.

Findings

The findings suggest the market “trajectory” is towards products other than the “traditional” ILS. Literature describing ILS faults and remedies may be productively applied to these other products.

Research limitations/implications

The attempted meta‐analysis is not statistically valid, so it can only be used as “loosely” descriptive of the library automation market. The impact and potential utility of social computing tools is not addressed.

Practical implications

A redefined ILS includes the wide range of services libraries provide or attempt to provide, rather than operating within the narrow definition of the traditional ILS. The essay provides a wider range of products for inclusion in requests for proposals for new library systems, and suggests new criteria to evaluate library systems as a whole, and the constituent parts of such systems.

Originality/value

The findings, if applied to the creation of new requests for proposals for new library automation products, may make it easier for libraries to state their needs, and for vendors to create new systems to meet those needs.
Anthropologists in the library: a review of Studying Students
Authors: Seadle Michael
Published: December 2007

Purpose

The purpose of this paper is to review the book Studying Students: The Undergraduate Research Project at the University of Rochester edited by Nancy Fried Foster and Susan Gibbons.

Design/methodology/approach

The review first examines the methods used in the Rochester study, and then considers the conclusions for their local implications as well as their meaning for the library profession.

Findings

The Rochester study should serve as a wake‐up call for librarians that imagine they understand their user‐base. Over and over again in this book the authors note how much they learned about the students after studying them systematically and how surprising they found the results. It seems unlikely that the Rochester experience is unique.

Originality/value

The transformation that took place at the University of Rochester Libraries should serve as an example for the profession as a whole.
Interfacial reactions between Sn‐based solders and AgPt thick film metallizations on LTCC
Authors: Nousiainen Olli , Kangasvieri Tero , Rönkä Kari , Rautioaho Risto , Vähäkangas Jouko
Published: December 2007

Purpose

This paper aims to investigate the metallurgical reactions between two commercial AgPt thick films used as a solder land on a low temperature co‐fired ceramic (LTCC) module and solder materials (SnAgCu, SnInAgCu, and SnPbAg) in typical reflow conditions and to clarify the effect of excessive intermetallic compound (IMC) formation on the reliability of LTCC/printed wiring boards (PWB) assemblies.

Design/methodology/approach

Metallurgical reactions between liquid solders and AgPt metallizations of LTCC modules were investigated by increasing the number of reflow cycles with different peak temperatures. The microstructures of AgPt metallization/solder interfaces were analyzed using SEM/EDS investigation. In addition, a test LTCC module/PWB assembly with an excess IMC layer within the joints was fabricated and exposed to a temperature cycling test in a −40 to 125°C temperature range. The characteristic lifetime of the test assembly was determined using DC resistance measurements. The failure mechanism of the test assembly was verified using scanning acoustic microscopy and SEM investigation.

Findings

The results showed that the higher peak reflow temperature of common lead‐free solders had a significant effect on the consumption of the original AgPt metallization of LTCC modules. The results also suggested that the excess porosity of the metallization accelerated the degradation of the metallization layer. Finally, the impact of these adverse metallurgical effects on the actual failure mechanism in an LTCC/PWB assembly was demonstrated.

Originality/value

This paper proves how essential it is to know the actual LTCC metallization/solder interactions that occur during reflow soldering and to recognize their effect on solder joint reliability in LTCC module/PWB assemblies. Moreover, the adverse effect of using lead‐free solders on the degradation of Ag‐based metallizations and, consequently, on board level reliability is demonstrated. Finally, practical guidelines for selecting materials for second‐level solder interconnections of LTCC module are given.
Multiphysics simulation of microwave curing in micro‐electronics packaging applications
Authors: Tilford T. , Sinclair K.I. , Bailey C. , Desmulliez M.P.Y. , Goussettis G. , Parrott A.K. , Sangster A.J.
Published: December 2007

Purpose

This paper aims to present an open‐ended microwave curing system for microelectronics components and a numerical analysis framework for virtual testing and prototyping of the system, enabling design of physical prototypes to be optimized, expediting the development process.

Design/methodology/approach

An open‐ended microwave oven system able to enhance the cure process for thermosetting polymer materials utilised in microelectronics applications is presented. The system is designed to be mounted on a precision placement machine enabling curing of individual components on a circuit board. The design of the system allows the heating pattern and heating rate to be carefully controlled optimising cure rate and cure quality. A multi‐physics analysis approach has been adopted to form a numerical model capable of capturing the complex coupling that exists between physical processes. Electromagnetic analysis has been performed using a Yee finite‐difference time‐domain scheme, while an unstructured finite volume method has been utilized to perform thermophysical analysis. The two solvers are coupled using a sampling‐based cross‐mapping algorithm.

Findings

The numerical results obtained demonstrate that the numerical model is able to obtain solutions for distribution of temperature, rate of cure, degree of cure and thermally induced stresses within an idealised polymer load heated by the proposed microwave system.

Research limitations/implications

The work is limited by the absence of experimentally derived material property data and comparative experimental results. However, the model demonstrates that the proposed microwave system would seem to be a feasible method of expediting the cure rate of polymer materials.

Originality/value

The findings of this paper will help to provide an understanding of the behaviour of thermosetting polymer materials during microwave cure processing.
E‐strategy in the UK retail grocery sector: a resource‐based analysis
Authors: Ellis‐Chadwick Fiona , Doherty Neil F. , Anastasakis Leonidas
Published: December 2007

Purpose

The purpose of this paper is to develop a better understanding of the expansion and development strategies used by retailers based in the UK for creating sustained competitive advantage in online grocery retailing.

Design/methodology/approach

The objectives of this research were addressed by using a qualitative research strategy consisting of two specific methods of data collection: primary and secondary data collection.

Findings

The study suggests that retailers have tended to follow an incremental approach towards the development and expansion of their online service provision. This route to expansion involves the trialling of new ideas, keeping close watch on the competition while endeavouring to introduce innovative new services to capture consumer interest and deliver customer benefits.

Research limitations/implications

The major limitation associated with this study is with respect to its heavy reliance on secondary sources. Consequently, assumptions have had to be made about the retailers' strategic thinking, as we were not able to secure any first hand accounts. However, in terms of the research implications, this study has both demonstrated the value of secondary data sources, and highlighted the benefits of adopting a resource‐based analysis.

Practical implications

The findings highlight the importance of viewing an organisation's web‐based IT resources, as being only one element of its e‐commerce strategy.

Originality/value

This study makes a major contribution in two ways. First, it has mapped out the strategic pathways followed by the UK's five leading grocery retailers, in terms of their adoption of e‐commerce during the first complete decade of online retailing. Second, the paper has demonstrated how the resource‐based theory provides a very useful lens through which these pathways can be viewed and ultimately explained.
Antecedents of organizational politics perceptions in Kuwait business organizations
Authors: Muhammad Ali H.
Published: December 2007

Purpose

This paper aims to examine three sets of antecedents of organizational politics perceptions: organizational antecedents, job work context antecedents, and personal antecedents.

Design/methodology/approach

Survey data were collected from 206 full‐time Arab employees of seven Kuwaiti companies and four industries (financial services, investment, real estate, and communication).

Findings

Results of multiple regression analysis showed job/work context factors and hierarchical level to be significant predictors of perceptions of organizational politics. However, contrary to the findings of previous research, formalization and centralization did not have a significant effect on organizational politics perceptions.

Research limitations/implications

The potential for common method variance that may be associated with the use of a single source, self‐report methodology of data collection represents a limitation.

Practical implications

The study is very useful in raising the level of awareness of managers, at various levels of the organization, of the potential consequences of their political behavior to their employees.

Originality/value

This study expands such research on organizational politics in a different cultural setting, one that is characterized by lower individualism and higher power distance.
REIT returns: between the Pacific and the Atlantic
Authors: Diane Li Deqing , Yung Kenneth
Published: December 2007

Purpose

The purpose of this paper is twofold in examining the international transmission of REIT returns volatility. The first purpose is to add to the literature on whether the real estate securities market and the broader equity market are integrated. The second objective of the study is to determine whether geographic risk factors can be transmitted beyond their region of influence.

Design/methodology/approach

The study uses the GARCH(1, 1), EGARCH, and GARCH‐M models.

Findings

The results show that there are significant international spillovers of REIT returns volatility within the Pacific region. The results also show that there are significant volatility transmissions between the Pacific and the Atlantic regions.

Practical implications

The results are consistent with the implication that the real estate sector and the general equity market are integrated such that geographic risk can be transmitted across national borders. The result will have major implications for international investment strategies.

Originality/value

To date, there has been no published study on the international transmission of REIT returns volatility. This study therefore examines whether the conditional variance of REIT returns of a country is affected by volatility transmission across markets in the same region using four Pacific markets.
Auditors as monitors: evidence from discretionary accruals of Laventhol and Horwath clients
Authors: Reed Brad J. , Lovata Linda M. , Costigan Michael L. , Ortegren Alan K.
Published: December 2007

Purpose

This paper aims to provide evidence on the hypothesis that auditors differ in how they constrain discretionary accruals (DAs) of their clients. The paper seeks to analyze changes in DAs for clients of Laventhol and Horwath associated with the appointment of a successor auditor.

Design/methodology/approach

The study uses regression and archival data to separate a firm's accounting accruals into discretionary and non‐DAs. The study then examines changes in a firm's DAs associated with a change in auditors.

Findings

Replacing LH with a new auditor resulted in a statistically significant decrease in DAs. This result is contrary to prior research and could be due to the prior research using voluntary auditor changes where variables such as financial distress and opinion shopping could drive the results.

Originality/value

The study provides results that differ from prior research. This study shows that the auditor change is associated with a systematic decline in the level of a firm's DAs. The results could be due to the forced nature of this auditor change as opposed to voluntary auditor changes used in prior research.
The social and ethical aspects connected with e‐space development
Authors: Wielki Janusz
Published: December 2007

Purpose

The purpose of this paper is, firstly, an analysis of the behavior of entities operating in the virtual space (termed in the paper “e‐space”) which has emerged and has been continuously developing around the internet (understood in a purely technical way as a global network infrastructure) and, secondly, to create a framework of the impact of these entities on an organization, especially in the context of emerging new ethical challenges. The motivation for undertaking this research was a lack of literature on such a holistic approach to this important problem facing contemporary organizations and the systematization of these issues.

Design/methodology/approach

The framework proposed in the paper was developed based on analyses of case studies of organizations from various industries which use the internet and the inter‐related mobile infrastructure. To create this framework the stakeholder theory and the cost‐benefit analysis approach were used.

Findings

The basic findings of the paper include a classification of the entities operating in e‐space and a taxonomy of the possible influences they may have on an organization. It is intended that the proposed framework be tested in selected industries.

Practical implications

It seems that the holistic approach presented in this paper has significant practical implications for the increasing number of organizations utilizing the on‐line environment in their business practices, offering them a far better understanding of the whole complexity of problems and challenges connected with the e‐economy phenomena.

Originality/value

The new and original aspects of the paper are the introduction and defining of the term e‐space; a classification of the elements operating there and the proposal of a taxonomy of the possible types of influence of these entities on an organization.
Amt2 Permease Is Required To Induce Ammonium-Responsive Invasive Growth and Mating in
Cryptococcus neoformans
Authors: Rutherford Julian C. , Lin Xiaorong , Nielsen Kirsten , Heitman Joseph
Published: December 2007

The conserved AmtB/Mep/Rh family of proteins mediate the transport of ammonium across cellular membranes in a wide range of organisms. Certain fungal members of this group are required to initiate filamentous growth. We have investigated the functions of two members of the AmtB/Mep/Rh family from the pathogenic basidiomycete
Cryptococcus neoformans
. Amt1 and Amt2 are low- and high-affinity ammonium permeases, respectively, and a mutant lacking both permeases is unable to grow under ammonium-limiting conditions.
AMT2
is transcriptionally induced in response to nitrogen limitation, whereas
AMT1
is constitutively expressed. Single and double
amt
mutants exhibit wild-type virulence in two models of cryptococcosis. Consistent with this, the formation of two
C. neoformans
virulence factors, cell wall melanin and the extracellular polysaccharide capsule, is not impaired in cells lacking either or both of the Amt1 and Amt2 permeases. Amt2 is, however, required for the initiation of invasive growth of haploid cells under low-nitrogen conditions and for the mating of wild-type cells under the same conditions. We propose that Amt2 may be a new fungal ammonium sensor and an element of the signaling cascades that govern the mating of
C. neoformans
in response to environmental nutritional cues.
Combination of Two Regulatory Elements in the
Tetrahymena thermophila HSP70-1
Gene Controls Heat Shock Activation
Authors: Barchetta Sabrina , La Terza Antonietta , Ballarini Patrizia , Pucciarelli Sandra , Miceli Cristina
Published: December 2007

The induction of heat shock genes (
HSP
s) is thought to be primarily regulated by heat shock transcription factors (HSFs), which bind target sequences on HSP promoters, called heat shock elements (HSEs). In this study, we investigated the 5′ untranslated regions of the
Tetrahymena thermophila HSP70-1
gene, and we found, in addition to the canonical and divergent HSEs, multiple sets of GATA elements that have not been reported previously in protozoa. By means of in vivo analysis of a green fluorescent protein reporter transgene driven by the
HSP70-1
promoter, we demonstrate that HSEs do not represent the minimal regulatory elements for heat shock induction, since the
HSP70-1
is tightly regulated by both HSE and GATA elements. Electrophoretic mobility shift assay also showed that HSFs are constitutively bound to the HSEs, whereas GATA elements are engaged only after heat shock. This is the first demonstration by in vivo analysis of functional HSE and GATA elements in protozoa. Furthermore, we provide evidence of a functional link between HSE and GATA elements in the activation of the heat shock response.
Galactosyl Transferases in Mycobacterial Cell Wall Synthesis
Authors: Beláňová Martina , Dianišková Petronela , Brennan Patrick J. , Completo Gladys C. , Rose Natisha L. , Lowary Todd L. , Mikušová Katarína
Published: December 2007

Two galactosyl transferases can apparently account for the full biosynthesis of the cell wall galactan of mycobacteria. Evidence is presented based on enzymatic incubations with purified natural and synthetic galactofuranose (Gal
f
) acceptors that the recombinant galactofuranosyl transferase, GlfT1, from
Mycobacterium smegmatis
, the
Mycobacterium tuberculosis
Rv3782 ortholog known to be involved in the initial steps of galactan formation, harbors dual β-(1→4) and β-(1→5) Gal
f
transferase activities and that the product of the enzyme, decaprenyl-P-P-GlcNAc-Rha-Gal
f
-Gal
f
, serves as a direct substrate for full polymerization catalyzed by another bifunctional Gal
f
transferase, GlfT2, the Rv3808c enzyme.
Evolution of Acetoclastic Methanogenesis in
Methanosarcina
via Horizontal Gene Transfer from Cellulolytic
Clostridia
Authors: Fournier Gregory P. , Gogarten J. Peter
Published: December 2007

Phylogenetic analysis confirmed that two genes required for acetoclastic methanogenesis,
ackA
and
pta
, were horizontally transferred to the ancestor of
Methanosarcina
from a derived cellulolytic organism in the class
Clostridia
. This event likely occurred within the last 475 million years, causing profound changes in planetary methane biogeochemistry.
Regulation of the
yjjQ
-
bglJ
Operon, Encoding LuxR-Type Transcription Factors, and the Divergent
yjjP
Gene by H-NS and LeuO
Authors: Stratmann Thomas , Madhusudan S. , Schnetz Karin
Published: December 2007

The
yjjQ
and
bglJ
genes encode LuxR-type transcription factors conserved in several enterobacterial species. YjjQ is a potential virulence factor in avian pathogenic
Escherichia coli
. BglJ counteracts the silencing of the
bgl
(β-glucoside) operon by H-NS in
E. coli
K-12. Here we show that
yjjQ
and
bglJ
form an operon carried by
E. coli
K-12, whose expression is repressed by the histone-like nucleoid structuring (H-NS) protein. The LysR-type transcription factor LeuO counteracts this repression. Furthermore, the
yjjP
gene, encoding a membrane protein of unknown function and located upstream in divergent orientation to the
yjjQ
-
bglJ
operon, is likewise repressed by H-NS. Mapping of the promoters as well as the H-NS and LeuO binding sites within the 555-bp intergenic region revealed that H-NS binds to the center of the AT-rich regulatory region and distal to the divergent promoters. LeuO sites map to the center and to positions distal to the
yjjQ
promoters, while one LeuO binding site overlaps with the divergent
yjjP
promoter. This latter LeuO site is required for full derepression of the
yjjQ
promoters. The arrangement of regulatory sites suggests that LeuO restructures the nucleoprotein complex formed by H-NS. Furthermore, the data support the conclusion that LeuO, whose expression is likewise repressed by H-NS and which is a virulence factor in
Salmonella enterica
, is a master regulator that among other loci, also controls the
yjjQ-bglJ
operon and thus indirectly the presumptive targets of YjjQ and BglJ.
Genetic and Functional Properties of the Self-Transmissible
Yersinia enterocolitica
Plasmid pYE854, Which Mobilizes the Virulence Plasmid pYV
Authors: Hammerl Jens A. , Klein Iris , Lanka Erich , Appel Bernd , Hertwig Stefan
Published: December 2007

Yersinia
strains frequently harbor plasmids, of which the virulence plasmid pYV, indigenous in pathogenic strains, has been thoroughly characterized during the last decades. Yet, it has been unknown whether the nonconjugative pYV can be transferred by helper plasmids naturally occurring in this genus. We have isolated the conjugative plasmids pYE854 (95.5 kb) and pYE966 (70 kb) from a nonpathogenic and a pathogenic
Yersinia enterocolitica
strain, respectively, and demonstrate that both plasmids are able to mobilize pYV. The complete sequence of pYE854 has been determined. The transfer proteins and
oriT
of the plasmid reveal similarities to the F factor. However, the pYE854 replicon does not belong to the IncF group and is more closely related to a plasmid of gram-positive bacteria. Plasmid pYE966 is very similar to pYE854 but lacks two DNA regions of the larger plasmid that are dispensable for conjugation.
Cardiotrophin-1 stimulates intercellular adhesion molecule-1 and monocyte chemoattractant protein-1 in human aortic endothelial cells
Authors: Ichiki Tomoko , Jougasaki Michihisa , Setoguchi Manabu , Imamura Junichi , Nakashima Hitoshi , Matsuoka Tatsuru , Sonoda Masahiro , Nakamura Kazuhiko , Minagoe Shinichi , Tei Chuwa
Published: December 2007

Intercellular adhesion molecule-1 (ICAM-1) and monocyte chemoattractant protein-1 (MCP-1) play critical roles in mediating monocyte adhesion to the vascular endothelium and monocyte migration into the subendothelial regions of the vessels. Inasmuch as cardiotrophin-1 (CT-1), an IL-6-type cytokine, was expressed in human atherosclerotic plaque, we examined whether CT-1 induces monocyte adhesion and migration by stimulating gene and protein expressions of ICAM-1 and MCP-1 in human aortic endothelial cells (HAECs). Immunocytochemistry revealed that CT-1 increased intensity of ICAM-1 and MCP-1 immunoreactivity in HAECs. Adhesion assay and chemotaxis assay revealed that CT-1 increased human monocytic THP-1 cell adhesion to HAECs and promoted chemotaxis in THP-1 cells, which were attenuated by anti-ICAM-1 and anti-MCP-1 antibody, respectively. Western blot analysis showed that CT-1 increased phosphorylation of ERK1/2 MAP kinase, p38 MAP kinase, and Akt and that their inhibitors, PD-98059, SB-203580, and LY-294002, respectively, inhibited phosphorylation. RNase protection assay and ELISA demonstrated that CT-1 increased gene and protein expressions of ICAM-1 and MCP-1. EMSA revealed that CT-1 enhanced NF-κB DNA-binding activity. CT-1-mediated upregulation of ICAM-1 and MCP-1 was suppressed by PD-98059, SB-203580, LY-294002, and parthenolide. The present study demonstrates that CT-1 promotes monocyte adhesion and migration by stimulating ICAM-1 and MCP-1 through mechanisms that involve ERK1/2 MAP kinase, p38 MAP kinase, phosphatidylinositol 3-kinase, and NF-κB pathways and suggests that CT-1 plays an important role in the pathophysiology of vascular inflammation and atherosclerosis.
Coupling of endothelial injury and repair: an analysis using an in vivo experimental model
Authors: Nogueras Sonia , Merino Ana , Ojeda Raquel , Carracedo Julia , Rodriguez Mariano , Martin-Malo Alejandro , Ramírez Rafael , Aljama Pedro
Published: December 2007

The repair of the endothelium after inflammatory injury is essential to maintaining homeostasis. The link between inflammation-induced endothelial damage and repair has not been fully characterized in vivo. We have developed a rat model to evaluate the coupling of lipopolysaccharide (LPS)-induced endothelial injury and repair. Aortic endothelium injury was analyzed by both inmunohistochemistry and flow cytometry to quantify the number of endothelial cells and the percentage of apoptotic endothelial cells. We have also identified the percentage of circulating angiogenic cells capable of repairing the damaged endothelium. Erythropoietin was administered to inhibit LPS-induced endothelial apoptosis. Loss of the normal endothelial structure was observed in the aorta of the animals treated with LPS. Eight hours after LPS administration, the number of endothelial cells decreased by 40%, returning to normal after 24 h. There was a threefold increase in the percentage of circulating angiogenic cells, which did not return to normal levels until 48 h after LPS administration. Circulating angiogenic cell levels did not change when LPS-induced endothelial damage was prevented by erythropoietin. The endothelial injury caused by inflammation activates the mobilization of circulating angiogenic cells, thus completing endothelial repair. Inflammation without endothelial injury does not trigger the mobilization of circulating angiogenic cells.
Oxygen regulation of arterial smooth muscle cell proliferation and survival
Authors: Ray Julie Basu , Arab Sara , Deng Yupu , Liu Peter , Penn Linda , Courtman David W. , Ward Michael E.
Published: December 2007

The purpose of this study was to determine if hypoxia elicits different proliferative and apoptotic responses in systemic arterial smooth muscle cells incubated under conditions that do or do not result in cellular ATP depletion and whether these effects are relevant to vascular remodeling in vivo. Gene expression profiling was used to identify potential regulatory pathways. In human aortic smooth muscle cells (HASMCs) incubated at 3% O2, proliferation and progression through the G1/S interphase are enhanced. Incubation at 1% O2reduced proliferation, delayed G1/S transition, increased apoptotic cell death, and is associated with mitochondrial membrane depolarization and reduced cellular ATP levels. In aorta and mesenteric artery from rats exposed to hypoxia (10% O2, 48 h), both proliferation and apoptosis are increased, as are medial nuclear density and smooth muscle cell content. Although nuclear levels of hypoxia-inducible factor 1-α (HIF-1α) are increased to a similar extent in HASMCs incubated at 1 and 3% O2, expression of tumor protein p53, its transcriptional target p21, as well as their regulatory factors and downstream effectors, are differentially affected under these two conditions, suggesting that the bidirectional effects of hypoxia are mediated by this pathway. We conclude that hypoxia induces a state of enhanced cell turnover through increased rates of both smooth muscle cell proliferation and death. This confers the ability to remodel the vasculature in response to changing tissue metabolic needs while avoiding the accumulation of mutations that may lead to malignant transformation or the formation of abnormal vascular structures.
AT1receptor antagonism attenuates target organ effects of salt excess in SHRs without affecting pressure
Authors: Varagic Jasmina , Frohlich Edward D. , Susic Dinko , Ahn Jwari , Matavelli Luis , López Begoña , Díez Javier
Published: December 2007

Our recent studies have demonstrated that salt excess in the spontaneously hypertensive rat (SHR) produces a modestly increased arterial pressure while promoting marked myocardial fibrosis and structural damage associated with altered coronary hemodynamics and ventricular function. The present study was designed to determine the efficacy of an angiotensin II type 1 (AT1) receptor blocker (ARB) in the prevention of pressure increase and development of target organ damage from high dietary salt intake. Eight-week-old SHRs were given an 8% salt diet for 8 wk; their age- and gender-matched controls received standard chow. Some of the salt-loaded rats were treated concomitantly with ARB (candesartan; 10 mg·kg−1·day−1). The ARB failed to reduce the salt-induced rise in pressure, whereas it significantly attenuated left ventricular (LV) remodeling (mass and wall thicknesses), myocardial fibrosis (hydroxyproline concentration and collagen volume fraction), and the development of LV diastolic dysfunction, as shown by longer isovolumic relaxation time, decreased ratio of peak velocity of early to late diastolic waves, and slower LV relaxation (minimum first derivative of pressure over time/maximal LV pressure). Without affecting the increased pulse pressure by high salt intake, the ARB prevented the salt-induced deterioration of coronary and renal hemodynamics but not the arterial stiffening or hypertrophy (pulse wave velocity and aortic mass index). Additionally, candesartan prevented the salt-induced increase in kidney mass index and proteinuria. In conclusion, the ARB given concomitantly with dietary salt excess ameliorated salt-related structural and functional cardiac and renal abnormalities in SHRs without reducing arterial pressure. These data clearly demonstrated that angiotensin II (via AT1receptors), at least in part, participated importantly in the pressure-independent effects of salt excess on target organ damage of hypertension.
In vivo measurement of flow-mediated vasodilation in living rats using high-resolution ultrasound
Authors: Heiss Christian , Sievers Richard E. , Amabile Nicolas , Momma Tony Y. , Chen Qiumei , Natarajan Shobha , Yeghiazarians Yerem , Springer Matthew L.
Published: December 2007

In humans, endothelial vasodilator function serves as a surrogate marker for cardiovascular health and is measured as changes in conduit artery diameter after temporary ischemia [flow-mediated dilation (FMD)]. Here we present an FMD-related approach to study femoral artery (FA) vasodilation in anesthetized rats. Diameter and Doppler flow were monitored in the FA. Using high-resolution ultrasound (35 MHz) and automated analysis software, we detected dose-dependent vasodilation using established endothelium-independent [intravenous nitroglycerin EC50 = 3.3 × 10−6 mol/l, peak 21Δ% (SD 4)] and endothelium-dependent [intra-arterial acetylcholine EC50 = 1.3 × 10−6 mol/l, peak 27Δ% (SD 4)] pharmacological vasodilators. Wall shear stress induced by intra-aortic injection of adenosine and infusion of saline at increasing rates (1.5–4.5 ml/min) led to vasodilation at 1 to 2 min. Transient hindlimb ischemia by common iliac occlusion (5 min) led to reactive hyperemia with flow velocity and wall shear stress increase and was followed by FA dilation [16Δ% (SD 2)], the latter of which was completely abolished by nitric oxide synthase (NOS) inhibition with NG-monomethyl-l-arginine [1Δ% (SD 2)]. FMD was significantly reduced in adult 20–24-wk-old animals compared with 9- to 10-wk-old animals, consistent with age-dependent endothelial dysfunction [16Δ% (SD 3) vs. 10Δ% (SD 3), P < 0.05]. Whereas FMD was completely NOS dependent in 9- to 10-wk-old animals, NOS-dependent mechanisms accounted for only half of the FMD in 20–24-wk-old animals, with the remainder being blocked by charybdotoxin and apamin, suggesting a contribution of endothelium-derived hyperpolarizing factor. To our knowledge, this is the first integrative physiological model to reproducibly study FMD of conduit arteries in living rats.
Multiple antiapoptotic targets of the PI3K/Akt survival pathway are activated by epoxyeicosatrienoic acids to protect cardiomyocytes from hypoxia/anoxia
Authors: Dhanasekaran Anuradha , Gruenloh Stephanie K. , Buonaccorsi J. Noelle , Zhang Rong , Gross Garrett J. , Falck John R. , Patel Paresh K. , Jacobs Elizabeth R. , Medhora Meetha
Published: December 2007

Epoxyeicosatrienoic acids (EETs) reduce infarction of the myocardium after ischemia-reperfusion injury to rodent and dog hearts mainly by opening sarcolemmal and mitochondrial potassium channels. Other mediators for the action of EET have been proposed, although no definitive pathway or mechanism has yet been reported. Using cultured cells from two rodent species, immortalized myocytes from a mouse atrial lineage (HL-1) and primary myocytes derived from neonatal rat hearts, we observed that pretreatment with EETs (1 μM of 14,15-, 11,12-, or 8,9-EET) attenuated apoptosis after exposure to hypoxia and reoxygenation (H/R). EETs also preserved the functional beating of neonatal myocytes in culture after exposure to H/R. We demonstrated that EETs increased the activity of the prosurvival enzyme phosphatidylinositol 3-kinase (PI3K). In fact, cardiomyocytes pretreated with EET and exposed to H/R exhibited antiapoptotic changes in at least five downstream effectors of PI3K, protein kinase B (Akt), Bcl-xL/Bcl-2-associated death promoter, caspases-9 and -3 activities, and the expression of the X-linked inhibitor of apoptosis, compared with vehicle-treated controls. The PI3K/Akt pathway is one of the strongest intracellular prosurvival signaling systems. Our studies show that EETs regulate multiple molecular effectors of this pathway. Understanding the targets of action of EET-mediated protection will promote the development of these fatty acids as therapeutic agents against cardiac ischemia-reperfusion.
Identity of the renin cell is mediated by cAMP and chromatin remodeling: an in vitro model for studying cell recruitment and plasticity
Authors: Pentz Ellen Steward , Sequeira Lopez Maria Luisa S. , Cordaillat Magali , Gomez R. Ariel
Published: December 2007

The renin-angiotensin system (RAS) regulates blood pressure and fluid-electrolyte homeostasis. A key step in the RAS cascade is the regulation of renin synthesis and release by the kidney. We and others have shown that a major mechanism to control renin availability is the regulation of the number of cells capable of making renin. The kidney possesses a pool of cells, mainly in its vasculature but also in the glomeruli, capable of switching from smooth muscle to endocrine renin-producing cells when homeostasis is threatened. The molecular mechanisms governing the ability of these cells to turn the renin phenotype on and off have been very difficult to study in vivo. We, therefore, developed an in vitro model in which cells of the renin lineage are labeled with cyan fluorescent protein and cells actively making renin mRNA are labeled with yellow fluorescent protein. The model allowed us to determine that it is possible to culture cells of the renin lineage for numerous passages and that the memory to express the renin gene is maintained in culture and can be reenacted by cAMP and chromatin remodeling (histone H4 acetylation) at the cAMP-responsive element in the renin gene.
IP3receptor-dependent Ca2+release modulates excitation-contraction coupling in rabbit ventricular myocytes
Authors: Domeier Timothy L. , Zima Aleksey V. , Maxwell Joshua T. , Huke Sabine , Mignery Gregory A. , Blatter Lothar A.
Published: December 2007

Inositol 1,4,5-trisphosphate (IP3) receptor (IP3R)-dependent Ca2+signaling exerts positive inotropic, but also arrhythmogenic, effects on excitation-contraction coupling (ECC) in the atrial myocardium. The role of IP3R-dependent sarcoplasmic reticulum (SR) Ca2+release in ECC in the ventricular myocardium remains controversial. Here we investigated the role of this signaling pathway during ECC in isolated rabbit ventricular myocytes. Immunoblotting of proteins from ventricular myocytes showed expression of both type 2 and type 3 IP3R at levels ∼3.5-fold less than in atrial myocytes. In permeabilized myocytes, direct application of IP3(10 μM) produced a transient 21% increase in the frequency of Ca2+sparks ( P < 0.05). This increase was accompanied by a 13% decrease in spark amplitude ( P < 0.05) and a 7% decrease in SR Ca2+load ( P < 0.05) and was inhibited by IP3R antagonists 2-aminoethoxydiphenylborate (2-APB; 20 μM) and heparin (0.5 mg/ml). In intact myocytes endothelin-1 (100 nM) was used to stimulate IP3production and caused a 38% ( P < 0.05) increase in the amplitude of action potential-induced (0.5 Hz, field stimulation) Ca2+transients. This effect was abolished by the IP3R antagonist 2-APB (2 μM) or by using adenoviral expression of an IP3affinity trap that buffers cellular IP3. Together, these data suggest that in rabbit ventricular myocytes IP3R-dependent Ca2+release has positive inotropic effects on ECC by facilitating Ca2+release through ryanodine receptor clusters.
Dose-related effects of red wine and alcohol on hemodynamics, sympathetic nerve activity, and arterial diameter
Authors: Spaak Jonas , Merlocco Anthony C. , Soleas George J. , Tomlinson George , Morris Beverley L. , Picton Peter , Notarius Catherine F. , Chan Christopher T. , Floras John S.
Published: December 2007

The cardiovascular benefits of light to moderate red wine consumption often have been attributed to its polyphenol constituents. However, the acute dose-related hemodynamic, vasodilator, and sympathetic neural effects of ethanol and red wine have not been characterized and compared in the same individual. We sought to test the hypotheses that responses to one and two alcoholic drinks differ and that red wine with high polyphenol content elicits a greater effect than ethanol alone. Thirteen volunteers (24–47 yr; 7 men, 6 women) drank wine, ethanol, and water in a randomized, single-blind trial on three occasions 2 wk apart. One drink of wine and ethanol increased blood alcohol to 38 ± 2 and 39 ± 2 mg/dl, respectively, and two drinks to 72 ± 4 and 83 ± 3 mg/dl, respectively. Wine quadrupled plasma resveratrol ( P < 0.001) and increased catechin ( P < 0.03). No intervention affected blood pressure. One drink had no heart rate effect, but two drinks of wine increased heart rate by 5.7 ± 1.6 beats/min; P < 0.001). Cardiac output fell 0.8 ± 0.3 l/min after one drink of ethanol and wine (both P < 0.02) but increased after two drinks of ethanol (+0.8 ± 0.3 l/min) and wine (+1.2 ± 0.3 l/min) ( P < 0.01). One alcoholic drink did not alter muscle sympathetic nerve activity (MSNA), while two drinks increased MSNA by 9–10 bursts/min ( P < 0.001). Brachial artery diameter increased after both one and two alcoholic drinks ( P < 0.001). No beverage augmented, and the second wine dose attenuated ( P = 0.02), flow-mediated vasodilation. One drink of ethanol dilates the brachial artery without activating sympathetic outflow, whereas two drinks increase MSNA, heart rate, and cardiac output. These acute effects, which exhibit a narrow dose response, are not modified by red wine polyphenols.