bluuebunny/crossref_metadata_2025 huggingface dataset:
A proposed ethical warrant for global knowledge representation and organization systems
Authors: Beghtol Clare
Published: September 2002

New technologies have made the increased globalization of information resources and services possible. In this situation, it is ethically and intellectually beneficial to protect cultural and information diversity. This paper analyzes the problems of creating ethically based globally accessible and culturally acceptable knowledge representation and organization systems, and foundation principles for the ethical treatment of different cultures are established on the basis of the United Nations Universal Declaration of Human Rights (UDHR). The concept of “cultural hospitality”, which can act as a theoretical framework for the ethical warrant of knowledge representation and organization systems, is described. This broad discussion is grounded with an extended example of one cultural universal, the concept of time and its expression in calendars. Methods of achieving cultural and user hospitality in information systems are discussed for their potential for creating ethically based systems. It is concluded that cultural hospitality is a promising concept for assessing the ethical foundations of new knowledge representation and organization systems and for planning revisions to existing systems.
Co‐term network analysis as a means of describing the information landscapes of knowledge communities across sectors
Authors: Jacobs Neil
Published: September 2002

Many and varied information sources are used by researchers and managers across sectors relevant to public policy development. When aggregated, these sources can be described in terms of sector‐specific information landscapes. This paper describes results from a survey that investigated such landscapes and relates them to the working practices of those for whom they were relevant. This is achieved through the use of co‐word or co‐term analysis, a technique derived from actor‐network theory. This technique allows for the production of graphic plots of normalised free text term pairs, which take into account inclusiveness. The results suggest that knowledge communities can be identified by this technique.
Evidence for the existence of geographic trends in university Web site interlinking
Authors: Thelwall Mike
Published: September 2002

The Web is an important medium for scholarly communication of various types, perhaps eventually to replace entirely some traditional mechanisms such as print journals. Yet the Web analogy of citations, hyperlinks, are much more varied in use and existing citation techniques are difficult to generalise to the new medium. In this context, one new challenging object of study is the modern multi‐faceted, multi‐genre, partly unregulated university Web site. This paper develops a methodology to analyse the patterns of interlinking between university Web sites and uses it to indicate that the degree of interlinking decreases with distance, at least in the UK. This is perhaps not in itself a surprising result, despite claims of a paradigm shift from the traditional virtual college towards collaboratories, but the methodology developed can also be used to refine existing Web link metrics to produce more powerful tools for comparing groups of sites.
Strategic reorientation in former public utilities: the example of UK electricity
Authors: Ghobadian Abby , Viney Howard
Published: September 2002

Much current discussion of strategic content focuses upon the elaboration and refinement of existing strategies, rather than upon the demands of strategic reorientation. This lack of attention is particularly in relation to organisations undergoing market liberalisation. Consequently, our understanding of the complex outcomes resulting from the deregulation of industries is yet nascent. This paper reports empirical research undertaken in the United Kingdom aimed at identifying viable combinations of corporate and business level strategy within a regulated environment, the recently privatised UK electricity industry. The conclusions reached by the authors suggest that despite the introduction of competition to the industry, companies seeking superior market performance face limited options in their choice of strategic content. Key success criteria for companies in competitive segments of the industry are the achievement of critical mass and of some form of integration, while companies operating in regulated segments may face a very limited choice of strategic approach.
Supply side short‐circuiting in design and build projects
Authors: Knight A.D. , Griffith A. , King A.P.
Published: September 2002

Design and build is becoming an increasingly adopted procurement solution for construction projects. Characterised by its integrated team approach, it allows the construction contractor to take a more central role in the design process than its traditional alternatives. Its global popularity and rate of adoption necessitate greater understanding by those involved, particularly client organisations whose primary business is not construction. This research is focused on understanding the team dynamics at the pre‐tender stage. Employing a grounded theory methodology and semi‐structured interviews, the central theme of “short‐circuiting” the tender development process by architects emerged. Four major themes responsible for short‐circuiting are: the quality and distribution of the “employer’s requirements”; architect’s unwillingness to realign their role with design and build; clarity of the contractor’s communication channels; and client’s misunderstanding of the time required to successfully procure buildings. The short‐circuiting manifests itself in a confusion of roles and responsibility of the parties involved, leading to client dissatisfaction in the finished construction product.
Effective strategic planning in small and medium sized firms
Authors: O’Regan Nicholas , Ghobadian Abby
Published: September 2002

Little attention has been paid to the strategy‐making processes of small and medium‐sized firms (SMEs), or to the effectiveness of strategic planning in the SME sector. Planning often fails because of implementation problems often associated with SMEs’ lack of capability to determine and overcome potential barriers to strategic planning. This paper examines the concept of formal strategic planning, presents the findings of a critical analysis of the suitability of formal planning for SMEs, and identifies some of the barriers which prevent effective implementation of strategic plans. Suggests that SMEs that engage in formal strategic planning experience fewer barriers to implementation than those that do not and that subsidiary firms tend to place a greater emphasis on formal planning than independent firms. Indicates that the eight barriers to deployment examined are experienced to a lesser degree by subsidiary firms compared with independent firms. However, the differences are not statistically significant. Suggests that apart from the preparation of written strategic plans by subsidiary firms, there is little transferability from the parent firm of influences that impact on the reduction or elimination of barriers to the deployment of strategic plans. Parent firms may wish to encourage their subsidiary firms to think and act as part of a larger group and to make greater use of the more significant resources of the parent firm.
On the incentive for price‐taking behavior
Authors: Huang Weihong
Published: September 2002

Price‐taking has long been mistakenly regarded as an inferior firm behavior in an imperfectly competitive market. This scenario is challenged when a “Naiver’s Paradox” is shown to exist in an oligopolic market where all firms produce the same product with the same technology (cost structure). It is shown that a firm behaving as a naive price‐taker with ignorance of its output impact on the market will perform no worse or even better than its rivals in terms of profits achieved, where the latter are assumed to take “Cournot”, “relative profit” or other more advanced strategies. More significantly, when the number of firms in the market is large, a price‐taker may achieve higher profit not only in a relative sense, but also in an absolute sense. Such paradoxical outcome is generic, for it results from neither ad hoc assumptions on market structure nor on information sets, but from the conventionally granted “convexity” assumption on cost functions. An analogous phenomenon is observed for oligopsony market.
Service quality in the Thai telecommunication industry: a tool for achieving a sustainable competitive advantage
Authors: Johnson William C. , Sirikit Anuchit
Published: September 2002

The objectives of this paper are to provide an overview of service quality and discuss its potential for offering a competitive advantage; to test several research propositions concerning service quality in the Thai telecommunications industry; and to offer managerial implications of the study’s findings and provide directions for future research. The results indicated that perceptions and expectations of service quality level showed no significant difference. A post hoc analysis found that the telecommunication industry received excellent ratings on tangibles, particularly customer service staff’s dress, and low ratings on empathy, particularly service providers’ interest differences. Tangibles are an aspect of service quality that is extremely important to the Thai telecommunication customer. This study provides evidence supporting the proposition that consumers distinguish between the performance cues of customer‐contact employee groups. Service delivery systems should create positive moments of truth by ensuring that the point of customers’ contact is reduced to a minimum.
The development of Russian e‐commerce: the case of Ozon
Authors: Hawk Stephen
Published: September 2002

E‐commerce in Russia is in an early phase of development. The online bookseller, Ozon, is one of the earliest and best‐known examples of business‐to‐customer e‐commerce in Russia. In developing its business, Ozon has faced and dealt with many difficulties present in the Russian economic and business environment. The development of Ozon’s business has required it to resolve many challenges that are likely to be faced by other online retailers in Russia. These challenges, and Ozon’s solutions to them, are presented. The case of Ozon is illustrative of the challenges faced by many Russian e‐commerce firms, and can be used to draw some initial conclusions about what tactics could employed to deal with the peculiarities of doing business online in Russia.
Managing international trade: an analysis of South African SMEs and regional exports
Authors: Soontiëns W.
Published: September 2002

Although South African small and medium‐sized enterprises (SMEs) are supported by various initiatives from the government, only a limited number (3 per cent) of firms enter the international export arena. The paper briefly sketches the role of SMEs in South Africa and their involvement in exports. Based on primary data, the significance of different obstacles to trade in the Southern African Development Community (SADC) is discussed. The listing of obstacles and their significance supplies both enterprises and policy makers with crucial information with respect to regional exports. By addressing these obstacles, South African SMEs will be encouraged to increase their exports to neighbouring countries in the SADC.
Endorsement of the money ethic, income, and life satisfaction
Authors: Li‐Ping Tang Thomas , Kim Jwa K. , Li‐Na Tang Theresa
Published: September 2002

The present study investigated the money ethic scale among full‐time employees, part‐time employed students, and non‐employed university students. Confirmatory factor analyses results showed that there was a good fit between the three‐factor model and research data for full‐time employees and non‐employed students and a weaker fit for part‐time employees and the whole sample. Further, factors success and evil were predictors of income for full‐time employees. Money attitudes were not related to pay satisfaction. Factor budget was associated with life satisfaction for full‐time employees and non‐employed students. Full‐time employees in this sample tended to be older, male, and have higher education than part‐time employees and students. Non‐employed students tended to have higher life satisfaction, lower protestant work ethic, less type A behavior pattern, and think more strongly that money does not represent their success, that they budget money carefully, and that money is not evil than part‐time employees.
Can codes of ethics really produce consistent behaviours?
Authors: Farrell Brian J. , Cobbin Deirdre M. , Farrell Helen M.
Published: September 2002

The paper investigates the effectiveness of codes of ethics to influence the behaviour of employees. Vignettes are not part of the methodology as the core data come from the direct observations of behaviours reported by 25 top managers and 545 employees from eight large Australian enterprises. One aim of the research is to measure the consistency of the observed behavioural patterns among employees and to investigate the possible association of high consistency with particular ethics strategies. The research models are based on medians and tallies of percentage frequencies of behavioural patterns. Two matters of importance are concluded from the investigation. First, there is no discernible association between the consistency ratings of the enterprises and their particular strategies in ethics. Second, the analysis suggests that the strongest ethical culture affecting behaviour in the respondents comes from an external, shared source.
Occupational stress and health outcome among British and German managers
Authors: Kirkcaldy B.D. , Trimpop R.M. , Williams S.
Published: September 2002

A large sample of German and British managers selected from the private and public sectors completed the pressure management indicator (PMI). The PMI is a 120‐item self‐report questionnaire developed from the occupational stress indicator (OSI). The PMI provides a global measure as well as differentiated profiles of occupational stress. Outcome measures include work satisfaction, organisational security, organisational satisfaction, and commitment, as well as physical wellbeing (physical symptoms and exhaustion) and psychological health (anxiety depression, worry and resilience). In addition moderator variables are assessed including type A behaviour, internal locus of control and coping strategies. The data from the PMI show that, when compared with British managers, the German managers reported greater job satisfaction and lower levels of resilience. The German managers displayed substantially higher pressure from the home‐work interface but less pressure from the need to have their achievements recognised. German managers reported higher levels of impatience (a sub‐scale of type A behaviour), coupled with high internal control (extent to which individual feels able to influence and control events) and made more use of coping strategies, especially problem focussed measures.
Sexuality at work
Authors: Leung Alicia S.M.
Published: September 2002

The current study explored the dynamics of sexuality that are embodied in secretaries’ work experiences. The study found that sexuality infused the process for recruitment, selection, and personnel development in organisations, but it made a distinction between junior and senior secretaries. The study also revealed that the boss‐secretary relation was linked to Chinese cultural values and traditions, especially those associated with filial piety and respect for authority. The boss‐secretary relation remained personal, but the Confucian ethic governed and guided the behaviour within the relationships. Secretaries accepted the “patriarchal right” and were deferential and compliant to meet men’s professional and personal demands. In respect to the boss‐secretary relation, the male boss might be a soft father, a demanding master, or a peer‐like friend with some overlapping qualities. Father‐daughter discourse was the most visible aspect of structural domination. Limitations and implications for future study are discussed.
Are Indian expatriates in Sultanate of Oman under stress?
Authors: Deosthalee Pravin G.
Published: September 2002

Stress among expatriates has been studied from various perspectives. The present study attempts to assess the occupational stress experienced by Indian expatriates working in Sultanate of Oman, and stress experienced by Indians working in India. The sample of 573 Indians working in Sultanate of Oman and 302 employees working in their motherland, Mumbai, India were selected. A.K. Srivasatava and A.P. Singh’s occupational stress index was used to measure the stress experienced by the Indians working in the Sultanate of Oman and those working in India. The results show that Indian females working in Sultanate of Oman experience more stress than their counterparts working in India. Personnel having post‐graduate qualifications working in Sultanate of Oman experience more stress than their counterparts working in India, and Indian expatriates over the age of 45 who are working in Sultanate of Oman experience more stress than their counterparts working in India.
The “Belbin” team role inventory: reinterpreting reliability estimates
Authors: Swailes Stephen , McIntyre‐Bhatty Tim
Published: September 2002

Previous research into the reliability of the “Belbin” team role self‐perception inventory has concluded that internal consistency reliability is poor, raising concerns about the validity of the inventory as a selection and development tool. This paper argues that, in overcoming the problem of unequal scale lengths between respondents, researchers have tampered with the true error variance contained within item response sets, leading to a misapplication of Cronbach’s alpha in this case. Using weighted average inter‐item correlation coefficients in a formula unrelated to scale length, alternative estimates of the internal consistency reliability of the TRSPI’s scales are derived. For a large data set (n=5,003), results show that the internal consistency of item responses is better than previous research suggests and tends towards the boundary at which internal consistency is considered acceptable in social and psychological research.
The relationship of customer satisfaction and service workers’ perceived control
Authors: Yagil Dana
Published: September 2002

The study examined three models that suggested direct, mediated, and moderated relationships among personality and situational variables relating to the service provider and customer satisfaction. Questionnaires were administered to 151 service provider‐customer dyads. The results support the model describing a mediation by job‐related control of the relationship between organizational variables relating to the service provider, on the one hand, and customer satisfaction, on the other. The service provider’s trait control was found to contribute to the prediction of job‐related control over and above the contribution of the organizational variables. Trait control moderates the relationship between empowering leadership and job‐related control, such that the relationship is significant only when trait control is low.
SYSTRA‐SQ: a new measure of bank service quality
Authors: Aldlaigan Abdullah H. , Buttle Francis A.
Published: September 2002

We describe the development of a new scale designed to measure service quality perceptions of retail bank customers. Empirical studies were performed in two waves. First, qualitative research was undertaken in the form of seven focus groups and 39 one‐to‐one interviews. These produced 963 text items that described customers’ service quality perceptions. These were categorised against the technical and functional service quality schema proposed by Grönroos. Then, a three‐phase, four‐sample, quantitative study was undertaken to derive a quantitative measure of technical and functional service quality. We have developed and validated a new 21‐item scale comprising four dimensions: service system quality, behavioural service quality, service transactional accuracy, and machine service quality. We found that customers evaluate SQ at two levels: organisational and transactional. The parsimony, reliability and validity of the scale suggest this is a measure of high utility to the banking industry.
The job satisfaction and performance of contingent and regular customer service representatives
Authors: Moshavi Dan , Terborg James R.
Published: September 2002

Although research on customer service representatives (CSRs) in call centers has increased in recent years, little attention has been paid to the growing use of contingent (temporary) CSRs in this setting. This study investigated the role that human capital plays in explaining the job satisfaction and performance of contingent and regular CSRs. Consistent with our expectations, contingent CSRs had less human capital but higher job satisfaction than regular workers. In addition, we found that human capital mediated the relationship between work status and job satisfaction. Contrary to expectations, no performance differences were found between contingent and regular CSRs. Implications for research and practice are discussed.
The factor structure of customer satisfaction
Authors: Matzler Kurt , Sauerwein Elmar
Published: September 2002

There is growing evidence that service quality attributes fall into three categories of factors that have a different impact on the formation of customer satisfaction. However, it is not clear which analytical procedure best identifies these factors. Vavra proposed a two‐dimensional importance grid based on customers’ self‐stated importance and derived importance using regression analysis. It is based on the assumption that there is a difference between self‐stated and derived importance and that by combining these importance weights, three groups of product or service attributes can be identified. Using data collected to measure customer satisfaction with the service of the IT department of a hospital, the authors test the underlying assumptions of the importance grid. They seem to be correct. When the results are compared with the penalty‐reward contrast analysis developed by Brandt, the two methods do not yield the same results. Therefore, the convergent validity of the importance grid has to be questioned. The paper closes with a discussion of the implications for research and practice.
Introducing Scirus: Elsevier’s shot at the title
Authors: Medeiros Norm
Published: September 2002

This article reviews Scirus, Elsevier Science’s search engine. Scirus is advertised as the world’s first scientific search engine. It indexes freely‐available Web sites, as well as proprietary content owned by Elsevier and its partners. Scirus was awarded “best specialty search engine” by Search Engine Watch, and may spark a trend whereby other content providers index their content with discipline‐specific Web sites.
Archival description and finding aids
Authors: Jimerson Randall C.
Published: September 2002

Archival arrangement and description establish physical and intellectual control over archives and manuscripts, enabling users to find the records they need. Description is the process of analyzing and recording information about these materials. The descriptive tools used to convey this information are called finding aids. In order to find manuscripts and archives when we need them, we must shift our orientation from single documents to groups of materials that can be described collectively. The principle of provenance likewise changes our focus from subject matter to the organic origins of documents, based on the purposes for which they were initially created and used. Archives and manuscripts are unique materials, but they can be organized and described using standards that permit data exchange and access by means of national networks, such as OCLC and RLIN, and through Web sites, using encoded archival description for archival finding aids. Descriptive practices continue to evolve, and improved systems are likely to be developed within the next decade.
Implementation of Dublin Core at the University of Alberta Libraries
Authors: Banski Erika
Published: September 2002

The article describes the application of the Dublin Core metadata scheme for the digital collections, the Alberta Folklore and Local History, housed at the University of Alberta Libraries. It highlights the metadata needs for describing an archival collection, a detailed metadata encoding structure, the metadata authority guidelines, and the use of controlled vocabulary. It concludes that the extended Dublin Core metadata element set derived from this project is also feasible for describing other locally developed digital collections.
The Austrian National Library’s card image catalog
Authors: Mueller Christa
Published: September 2002

For historical reasons, the Austrian National Library (ANL) had only 10 per cent of its 2.9 million items available in its OPAC as of 1997. Its unique holdings from the sixteenth to the nineteenth centuries could still only be found via card catalogs. In order to make these unique collections accessible via the Web, the library scanned each catalog card into a digital image. An in‐house software application called KatZoom was used to browse and search the catalog card images. Within less than half a year, ANL’s unique holdings became accessible via the Web. At a later time, these digital images were converted to electronic text and incorporated into the local library systems.
Cataloging and processing of special format science curriculum materials
Authors: Piascik Jeanne M.
Published: September 2002

The University of Central Florida’s Curriculum Materials Center acquired a number of science‐related instructional materials which were to be cataloged and added to the collection. Nearly all of the items were three‐dimensional artifacts (including games, models, and toys). Most of these items did not have records on OCLC and required original cataloging. Processing methods needed to be imaginative, and suitable containers were often obtained from less‐than‐traditional sources.
A Possible Dual Site of Action for Carbon Monoxide‐Mediated Chemoexcitation in the Rat Carotid Body
Authors: Barbé C. , Al‐Hashem F. , Conway A. F. , Dubuis E. , Vandier C. , Kumar P.
Published: September 2002

High tensions of carbon monoxide (CO), relative to oxygen, were used as a tool to investigate the mechanism of chemotransduction. In an in vitro whole organ, rat carotid body preparation, CO increased sinus nerve chemoafferent discharge in the dark, an effect that was significantly reduced (by ca 70 %) by bright white light and by the removal of extracellular Ca2+ from the superfusate or by the addition of either Ni2+ (2 mM) or methoxyverapamil (100 μM). Addition of the P2 purinoceptor antagonist pyridoxalphosphate‐6‐azophenyl‐2′,4′‐disulphonic acid (50 μM) also significantly reduced the neural response to CO. In perforated patch, whole‐cell recordings of isolated rat type I cells, CO induced a depolarisation of ca 11 mV and a decrease in the amplitude of an outward current around and above the resting membrane potential. Membrane conductance between ‐50 and ‐60 mV was significantly reduced by ca 40 % by CO. These effects were not photolabile and were present also when a ‘blocking solution’ containing TEA, 4‐AP, Ni2+ and zero extracellular Ca2+ was used. In conventional whole‐cell recordings, CO only decreased current amplitudes above +10 mV and was without effect around the resting membrane potential. These data demonstrate a direct effect of CO upon type I cell K+ conductances and strongly suggest an effect upon a background, leak conductance that requires an intracellular mediator. The photolabile effect of CO only upon afferent neural discharge adds further evidence to a dual site of action of CO with a separate action at the afferent nerve terminal that, additionally, requires the permissive action of the neurotransmitter ATP.
Influence of Different Cuff Inflation Protocols on Capillary Filtration Capacity in Human Calves ‐ A Congestion Plethysmography Study
Authors: Bauer A. , Bruegger D. , Gamble J. , Christ F.
Published: September 2002

It has been suggested that venous congestion plethysmography (VCP) substantially underestimates microvascular permeability by activation of a veni‐arteriolar constrictor mechanism, even when using small (< 25 mmHg) congestion pressure steps. We studied human lower limbs of 18 young healthy volunteers to test whether the congestion pressure step size of the VCP protocol has an influence on the values of the capillary filtration capacity (CFC) and isovolumetric venous pressure (Pvi). Two different dual stage VCP pressure step protocols, with 3 and 10 mmHg steps, were used in randomised order and separated by a transient reduction in congestion pressure. Since lymph flow is known to increase after venous congestion, we also looked to see if changes in the estimated lymph flow (JvL) occur as a result of these VCP protocols. The measured CFC (median [25th; 75th percentile]) was 2.6 [2.5; 3.2]× 10−3 ml (100 ml)−1 min−1 mmHg−1 with the 3 mmHg pressure step protocol, which was not different from the value of 2.9 [2.7; 3.4]× 10−3 ml (100 ml)−1 min−1 mmHg−1 obtained with 10 mmHg pressure steps. However, when either of these step sizes was applied after a transient venous decongestion, significantly higher values of CFC, 4.0 [3.4; 4.1]× 10−3 and 3.5 [3.1; 4.5]× 10−3 ml (100 ml)−1 min−1 mmHg−1, respectively, were obtained (P < 0.05). The assessment of Pvi was also independent of the pressure protocol (10 mmHg: 8.0 [5.7; 13.2] mmHg and 3 mmHg: 15.7 [12.5; 18.5] mmHg), but when Pvi was measured after the transient deflation, significantly higher values were found with both 10 and 3 mmHg steps (24.1 [20.9; 27.3] and 30.4 [28.9; 30.9] mmHg, respectively; P < 0.01). The transient pressure reduction was associated with a rise in estimated JvL from 0.04 [0.03; 0.05] to 0.12 [0.08; 0.18] and 0.04 [0.04; 0.05] to 0.09 [0.07; 0.10] ml (100 ml)−1 min−1, respectively (P < 0.01). The first stage data from these protocols shows that the value of CFC is not influenced by the size of the cumulative venous pressure steps, providing they are of 10 mmHg or less. The data also show that JvL can be estimated with small step VCP protocols. We hypothesise that the sudden reduction in cuff pressure after venous congestion is associated with a temporary upregulation of lymph flow. As the congestion pressure is raised again, there is a modulation of the enhanced lymph flow, such that the resulting CFC slope appears greater than that obtained in the first stage of the protocol.
The Scotopic Threshold Response of the Dark‐Adapted Electroretinogram of the Mouse
Authors: Saszik Shannon M. , Robson John G. , Frishman Laura J.
Published: September 2002

The most sensitive response in the dark‐adapted electroretinogram (ERG), the scotopic threshold response (STR) which originates from the proximal retina, has been identified in several mammals including humans, but previously not in the mouse. The current study established the presence and assessed the nature of the mouse STR. ERGs were recorded from adult wild‐type C57/BL6 mice anaesthetized with ketamine (70 mg kg−1) and xylazine (7 mg kg−1). Recordings were between DTL fibres placed under contact lenses on the two eyes. Monocular test stimuli were brief flashes (λmax 462 nm; ‐6.1 to +1.8 log scotopic Troland seconds(sc td s)) under fully dark‐adapted conditions and in the presence of steady adapting backgrounds (‐3.2 to ‐1.7 log sc td). For the weakest test stimuli, ERGs consisted of a slow negative potential maximal ≈200 ms after the flash, with a small positive potential preceding it. The negative wave resembled the STR of other species. As intensity was increased, the negative potential saturated but the positive potential (maximal ≈110 ms) continued to grow as the b‐wave. For stimuli that saturated the b‐wave, the a‐wave emerged. For stimulus strengths up to those at which the a‐wave emerged, ERG amplitudes measured at fixed times after the flash (110 and 200 ms) were fitted with a model assuming an initially linear rise of response amplitude with intensity, followed by saturation of five components of declining sensitivity: a negative STR (nSTR), a positive STR (pSTR), a positive scotopic response (pSR), PII (the bipolar cell component) and PIII (the photoreceptor component). The nSTR and pSTR were approximately 3 times more sensitive than the pSR, which was approximately 7 times more sensitive than PII. The sensitive positive components dominated the b‐wave up to > 5 % of its saturated amplitude. Pharmacological agents that suppress proximal retinal activity (e.g. GABA) minimized the pSTR, nSTR and pSR, essentially isolating PII which rose linearly with intensity before showing hyperbolic saturation. The nSTR, pSTR and pSR were desensitized by weaker backgrounds than those desensitizing PII. In conclusion, ERG components of proximal retinal origin that are more sensitive to test flashes and adapting backgrounds than PII provide the ‘threshold’ negative and positive (b‐wave) responses of the mouse dark‐adapted ERG. These results support the use of the mouse ERG in studies of proximal retinal function.
Role of Presynaptic Muscarinic and GABAB Receptors in Spinal Glutamate Release and Cholinergic Analgesia in Rats
Authors: Li De‐Pei , Chen Shao‐Rui , Pan Yu‐Zhen , Levey Allan I. , Pan Hui‐Lin
Published: September 2002

Spinally administered muscarinic receptor agonists or acetylcholinesterase inhibitors can produce effective pain relief. However, the analgesic mechanisms and the site of actions of cholinergic agents in the spinal cord are not fully understood. In this study, we investigated the mechanisms underlying cholinergic presynaptic regulation of glutamate release onto spinal dorsal horn neurons. The role of spinal GABAB receptors in the antinociceptive action of muscarine was also determined. Whole‐cell voltage‐clamp recordings were performed on visualized dorsal horn neurons in the lamina II in the spinal cord slice preparation of rats. The miniature excitatory postsynaptic currents (mEPSCs) and miniature inhibitory postsynaptic currents (mIPSCs) were recorded in the presence of tetrodotoxin. The evoked EPSCs (eEPSCs) were obtained by electrical stimulation of the dorsal root entry zone or the attached dorsal root. Nociception in rats was measured using a radiant heat stimulus and the effect of intrathecal administration of drugs tested. Acetylcholine (10–100 μM) reduced the amplitude of monosynaptic eEPSCs in a concentration‐dependent manner. Acetylcholine also significantly decreased the frequency of non‐NMDA receptor‐mediated mEPSCs, which was antagonized by atropine but not mecamylamine. The frequency of GABAA receptor‐mediated mIPSCs was significantly increased by acetylcholine and this excitatory effect was abolished by atropine. Existence of presynaptic M2 muscarinic receptors in the spinal dorsal horn was further demonstrated by immunocytochemistry staining and dorsal rhizotomy. CGP55845, a GABAB receptor antagonist, significantly attenuated the inhibitory effect of acetylcholine on the frequency of mEPSCs and the amplitude of monosynaptic eEPSCs in lamina II neurons. Furthermore, the antinociceptive action produced by intrathecal muscarine was significantly reduced by CGP55845 pretreatment in rats. Therefore, data from this integrated study provide new information that acetylcholine inhibits the glutamatergic synaptic input to lamina II neurons through presynaptic muscarinic receptors. Inhibition of glutamate release onto lamina II neurons by presynaptic muscarinic and GABAB heteroreceptors in the spinal cord probably contributes to the antinociceptive action of cholinergic agents.
The Relationship between Intracellular [Ca2+] and Ca2+ Wave Characteristics in Permeabilised Cardiomyocytes from the Rabbit
Authors: Loughrey C. M. , MacEachern K. E. , Neary P. , Smith G. L.
Published: September 2002

Spontaneous sarcoplasmic reticulum (SR) Ca2+ release and propagated intracellular Ca2+ waves are a consequence of cellular Ca2+ overload in cardiomyocytes. We examined the relationship between average intracellular [Ca2+] and Ca2+ wave characteristics. The amplitude, time course and propagation velocity of Ca2+ waves were measured using line‐scan confocal imaging of β‐escin‐permeabilised cardiomyocytes perfused with 10 μM Fluo‐3 or Fluo‐5F. Spontaneous Ca2+ waves were evident at cellular [Ca2+] > 200 nM. Peak [Ca2+] during a wave was 2.0–2.2 μM; the minimum [Ca2+] between waves was 120–160 nM; wave frequency was ≈0.1 Hz. Raising mean cellular [Ca2+] caused increases in all three parameters, particularly Ca2+ wave frequency. Increases in the rate of SR Ca2+ release and Ca2+ uptake were observed at higher cellular [Ca2+], indicating calcium‐sensitive regulation of these processes. At extracellular [Ca2+] > 2 μM, the mean [Ca2+] inside the permeabilised cell did not increase above 2 μM. This extracellular‐intracellular Ca2+ gradient could be maintained for periods of up to 5 min before the cardiomyocyte developed a sustained and irreversible hypercontraction. Inclusion of mitochondrial inhibitors (2 μM carbonyl cyanide m‐chlorophenylhydrazone and 2 μM oligomycin) while perfusing with > 2 μM Ca2+ abolished the extracellular‐intracellular Ca2+ gradient through the generation of Ca2+ waves with a higher peak [Ca2+] compared to control conditions. Under these conditions, cardiomyocytes rapidly (< 2 min) developed a sustained and irreversible contraction. These results suggest that mitochondrial Ca2+ uptake acts to delay an increase in [Ca2+] by blunting the peak of the Ca2+ wave.
Loss of Enteric Motor Neurotransmission in the Gastric Fundus of Sl/Sld Mice
Authors: Beckett Elizabeth A. H. , Horiguchi Kazuhide , Khoyi Mohammad , Sanders Kenton M. , Ward Sean M.
Published: September 2002

Studies of W/WV mice, which lack intramuscular interstitial cells of Cajal (IC‐IM), have suggested that IC‐IM act as mediators of enteric motor neurotransmission in the gastrointestinal tract. We have studied Sl/Sld mice, which lack the ability to make membrane‐bound stem cell factor, to determine the consequences of inappropriate stem cell factor expression on IC‐IM populations and on enteric motor neurotransmission. IC‐IM were found within the circular and longitudinal muscles of the gastric fundus of wild‐type mice. IC‐IM were intimately associated with motor nerve terminals and nerve varicosities formed synaptic structures with these cells. IC‐IM were also connected with neighbouring smooth muscle cells via gap junctions. Immunohistochemistry and electron microscopy showed that IC‐IM were absent from fundus muscles of Sl/Sld mice, but the density of excitatory and inhibitory nerves was not significantly different than in wild‐type muscles. Loss of IC‐IM was associated with decreased membrane noise (unitary potentials) and significant reductions in post‐junctional excitatory and inhibitory enteric nerve responses. Reductions in neural responses were not due to defects in smooth muscle cells as responses to exogenous ACh and K+‐induced depolarization were normal in Sl/Sld mice. Responses to neurally released ACh were revealed in Sl/Sld mice by inhibiting ACh breakdown with the acetylcholinesterase inhibitor neostigmine. Inhibitory nerve stimulation elicited inhibitory junction potentials (IJPs) and relaxations in wild‐type mice. IJPs were reduced in amplitude and relaxation responses were absent in Sl/Sld mice. These observations suggest that membrane‐bound stem cell factor is essential for development of IC‐IM and that the close, synaptic‐like relationship between nerve terminals and IC‐IM may be the primary site of innervation by enteric motor neurons in gastric muscles.
Sensory Afferent Selective Role of P2 Receptors in the Nucleus Tractus Solitarii for Mediating the Cardiac Component of the Peripheral Chemoreceptor Reflex in Rats
Authors: Paton Julian F. R. , de Paula Patrícia M. , Spyer K. Michael , Machado Benedito H. , Boscan Pedro
Published: September 2002

We have assessed the functional role of type 2 purinergic (P2) receptors within the caudal aspect of the commissural nucleus tractus solitarii (NTS) in mediating the peripheral chemoreceptor reflex cardiorespiratory response in the arterially perfusedin situworking heart‐brainstem preparation of rats. Microinjection in NTS of either suramin (100 pmol) or pyrinoxalphosphate‐6‐azophenyl‐2′,4′‐disulphonic acid tetrasodium salt (PPADS; 10 pmol) depressed the reflex bradycardia (by ≈50 %), but not the tachypnoea, following peripheral chemoreceptor stimulation. In contrast, the reflex bradycardia produced by stimulation of pharyngo‐oesophageal receptors was unaffected. Furthermore, microinjections in NTS of the P2X receptor agonist α,β‐methyleneadenosine 5′‐triphosphate (10 pmol) evoked a bradycardia which was antagonized by suramin (100 pmol). This P2X agonist reversibly potentiated the peripheral chemoreceptor‐evoked bradycardia. The effect of suramin was selective to purinergic receptors because the bradycardia evoked by microinjection of α,β‐methyleneadenosine 5′‐triphosphate was blocked while the bradycardic responses to microinjections of NMDA or non‐NMDA receptor agonists were not affected. From whole‐cell recordings, some NTS neurones received convergent excitatory synaptic inputs from both peripheral chemoreceptors and receptors at the pharyngo‐oesophageal junction. The excitatory postsynaptic response evoked by chemoreceptor stimulation was depressed by suramin, but convergent excitatory inputs from pharyngo‐oesophageal receptors were unperturbed. Our findings support the hypothesis that caudal commissural NTS P2 purinergic receptors play a role in the neurotransmission of the parasympathetic (bradycardic) component of the chemoreceptor reflex. This effect is highly selective in that the chemoreceptor afferent‐evoked tachypnoea, as well as other visceral receptor‐mediated reflex bradycardia, remain unaffected.
Comparative Capacitative Calcium Entry Mechanisms in Canine Pulmonary and Renal Arterial Smooth Muscle Cells
Authors: Wilson Sean M. , Mason Helen S. , Smith Gregory D. , Nicholson Neil , Johnston Louise , Janiak Robert , Hume Joseph R.
Published: September 2002

Experiments were performed to determine whether capacitative Ca2+ entry (CCE) can be activated in canine pulmonary and renal arterial smooth muscle cells (ASMCs) and whether activation of CCE parallels the different functional structure of the sarcoplasmic reticulum (SR) in these two cell types. The cytosolic [Ca2+] was measured by imaging fura‐2‐loaded individual cells. Increases in the cytosolic [Ca2+] due to store depletion in pulmonary ASMCs required simultaneous depletion of both the inositol 1,4,5‐trisphosphate (InsP3)‐ and ryanodine (RY)‐sensitive SR Ca2+ stores. In contrast, the cytosolic [Ca2+] rises in renal ASMCs occurred when the SR stores were depleted through either the InsP3 or RY pathways. The increase in the cytosolic [Ca2+] due to store depletion in both pulmonary and renal ASMCs was present in cells that were voltage clamped and was abolished when cells were perfused with a Ca2+‐free bathing solution. Rapid quenching of the fura‐2 signal by 100 μM Mn2+ following SR store depletion indicated that extracellular Ca2+ entry increased in both cell types and also verified that activation of CCE in pulmonary ASMCs required the simultaneous depletion of the InsP3‐ and RY‐sensitive SR Ca2+ stores, while CCE could be activated in renal ASMCs by the depletion of either of the InsP3‐ or RY‐sensitive SR stores. Store depletion Ca2+ entry in both pulmonary and renal ASMCs was strongly inhibited by Ni2+ (0.1–10 mM), slightly inhibited by Cd2+ (200–500 μM), but was not significantly affected by the voltage‐gated Ca2+ channel (VGCC) blocker nisoldipine (10 μM). The non‐selective cation channel blocker Gd3+ (100 μM) inhibited a portion of the Ca2+ entry in 6 of 18 renal but not pulmonary ASMCs. These results provide evidence that SR Ca2+ store depletion activates CCE in parallel with the organization of intracellular Ca2+ stores in canine pulmonary and renal ASMCs.
Age‐Dependent Synapse Withdrawal at Axotomised Neuromuscular Junctions in Wlds Mutant and Ube4b/Nmnat Transgenic Mice
Authors: Gillingwater Thomas H. , Thomson Derek , Mack Till G. A. , Soffin Ellen M. , Mattison Richard J. , Coleman Michael P. , Ribchester Richard R.
Published: September 2002

Axons in WldS mutant mice are protected from Wallerian degeneration by overexpression of a chimeric Ube4b/Nmnat (Wld) gene. Expression of Wld protein was independent of age in these mice. However we identified two distinct neuromuscular synaptic responses to axotomy. In young adult Wlds mice, axotomy induced progressive, asynchronous synapse withdrawal from motor endplates, strongly resembling neonatal synapse elimination. Thus, five days after axotomy, 50–90 % of endplates were still partially or fully occupied and expressed endplate potentials (EPPs). By 10 days, fewer than 20 % of endplates still showed evidence of synaptic activity. Recordings from partially occupied junctions indicated a progressive decrease in quantal content in inverse proportion to endplate occupancy. In Wlds mice aged > 7 months, axons were still protected from axotomy but synapses degenerated rapidly, in wild‐type fashion: within three days less than 5 % of endplates contained vestiges of nerve terminals. The axotomy‐induced synaptic withdrawal phenotype decayed with a time constant of ∼30 days. Regenerated synapses in mature Wlds mice recapitulated the juvenile phenotype. Within 4–6 days of axotomy 30–50 % of regenerated nerve terminals still occupied motor endplates. Age‐dependent synapse withdrawal was also seen in transgenic mice expressing the Wld gene. Co‐expression of Wld protein and cyan fluorescent protein (CFP) in axons and neuromuscular synapses did not interfere with the protection from axotomy conferred by the Wld gene. Thus, Wld expression unmasks age‐dependent, compartmentally organised programmes of synapse withdrawal and degeneration.
Regional Fat Metabolism in Human Splanchnic and Adipose Tissues; The Effect of Exercise
Authors: van Hall Gerrit , Bülow Jens , Sacchetti Massimo , Mulla Nariman Al , Lyngsø Dorthe , Simonsen Lene
Published: September 2002

This study was conducted to investigate the role of splanchnic and adipose tissue in the regulation of fatty acid (FA) metabolism at rest, during 1 h of semi‐recumbent cycle exercise at 60 % of maximal power output and 3 h of recovery. In six post‐absorptive healthy volunteers catheters were placed in a radial artery, hepatic vein and a subcutaneous vein on the anterior abdominal wall. Whole body, and regional splanchnic and adipose tissue FA metabolism were measured by a constant infusion of the stable isotopes [U‐13C] palmitate and [2H5] glycerol and according to Fick's principle. The whole body rate of extracellular FA reesterification was similar at rest and during exercise (≈290 μmol min−1) and increased during recovery to a plateau of 390 μmol min−1. FA and triacylglycerol (TAG) uptake by adipose tissue was undetectable, but a constant but small glycerol uptake of ≈25 nmol (100 g)−1 min−1 was observed. From the FA taken up by the splanchnic area, 13 % was oxidized, 5–11 % converted to ketone bodies, and ≈35 % incorporated in TAG released both at rest and at the third hour of recovery from exercise. Splanchnic FA reesterification could account for 51 % and 58 % of whole body extracellular FA reesterification, of which half was accounted for by TAG released from the splanchnic area, at rest and in recovery, respectively. In conclusion, in the post‐absorptive state, adipose tissue contributes very little to extracellular FA reesterification and splanchnic reesterification can account for 50–60 %, implying that FA reesterification in other tissues is important. The extracellular FA reesterification rate does not change with exercise but is higher during recovery. Furthermore, the uptake of glycerol by adipose tissue indicates that adipose tissue can metabolize glycerol.