bluuebunny/crossref_metadata_2025 huggingface dataset:
Political Science Methodology
Authors: Box-Steffensmeier Janet M. , Brady Henry E. , Collier David
Published: September 2009

Political methodology offers techniques for clarifying the theoretical meaning of concepts such as revolution and for developing definitions of revolutions. It also provides descriptive indicators for comparing the scope of revolutionary change, and sample surveys for gauging the support for revolutions. It then presents an array of methods for making causal inferences that provide insights into the causes and consequences of revolutions. An overview of the book is given. Topics addressed include social theory and approaches to social science methodology; concepts and development measurement; causality and explanation in social research; experiments, quasi-experiments, and natural experiments; general methods of quantitative tools for causal and descriptive inference; quantitative tools for causal and descriptive inference; qualitative tools for causal inference; and organizations, institutions, and movements in the field of methodology. In general, the Handbook provides overviews of specific methodologies, but it also emphasizes three things: utility for understanding politics, pluralism of approaches, and cutting across boundaries. This volume discusses interpretive and constructivist methods, along with broader issues of situating alternative analytic tools in relation to an understanding of culture.
Meta‐Methodology: Clearing the Underbrush
Authors: Bevir Mark
Published: September 2009

This article offers some explanations for the rise of causal thinking as the ‘behavioural revolution's’ reaction to the nineteenth century's teleological narratives about developmental historicism and early twentieth-century emphasis on modernist empiricism. It describes the philosophical issues that are indispensable to any discussion of the role of a given methodology. Each section after that on the traditions of political science concerns a particular subfield of philosophy — epistemology, ontology, and explanation. The emergence of modernist empiricism, behaviouralism, institutionalism, and rational choice in political science is reported. A comparative approach implies that political scientists are wrong if they think methods can ever justify causal claims or even the data they generate. This article attempted to clarify the underbrush of confusion that arises from reflecting on methods in terms of traditions of political science rather than philosophical subfields and doctrines.
Agent‐Based Modeling
Authors: de Marchi Scott , Page Scott E.
Published: September 2009

This article provides a discussion on agent-based modeling. Two examples that show the ability of computational methods to extend game-theoretic results are presented. It then discusses modeling agents, modeling agent interactions, and system behaviour. In addition, it describes how agent-based models differ from and complement mathematical models and concludes with some suggestions for how one might best leverage the strengths of agent-based models to advance political science. Most mathematical analyses of game-theoretic models do not look into the stability and attainability of their equilibria and would be made richer by complementing them with agent-based models that explored those properties. The ability of computational models to test the robustness of formal results would be reason alone to add them to tool kits. As a methodology, agent-based modeling should be considered as in its infancy, its enormous potential limited only by the scientific and creative talents of its practitioners.
Affect and Information Processing
Authors: Daniels Kevin
Published: September 2009

Psychometrically, affective experience can be represented in two dimensional space. More specific affects cluster at points in this space. These two major dimensions are negative and positive affect. High negative affect relates to the more specific unpleasant affects of anxiety and anger. Its opposite is relaxation. High positive affect relates to more specific pleasant and high activation affects such as enthusiasm. Its opposite relates to the more specific affects of depression and boredom. Because of the pervasive nature of affect, organizational research has investigated many theoretical and applied issues. The topics of this article include: how cognitive processes influence affect; how cognitive processes regulate affective experience; how state affect influences cognitive processes; and the role of trait affect. There are organizational applications in each domain. The article concludes by highlighting directions for research.
Norbert Elias's Impact on Organization Studies
Authors: van Iterson Ad
Published: September 2009

The impact of Norbert Elias's sociological writings on organization studies is still small. To date, his approach has been largely neglected by the field. In contrast, his influence on other sociological sub-disciplines is much larger, e.g. the sociology of sports, teaching, health and illness, knowledge, and of the welfare state. Arguably, his impact is strongest on general theoretical sociology. This may not come as a surprise. Although his magnum opus The Civilizing Process ([1939] 2000) provides a rich historical account of state formation and changing manners, morality, and habitus among secular upper classes in late medieval and the Ancien Régime (Old Order) France, it can best be read as primarily a critique of what Elias saw as the major flaws of contemporary sociological theorizing. This article attempts to show how Elias's ideas might open some new avenues of research for organization studies. It relies almost exclusively On The Civilizing Process, to the neglect of other important, but later works such as The Established And The Outsiders ([1965] 1994).
Organizations and the Chicago School
Authors: Abbott Andrew
Published: September 2009

Sociology's interest in organizations is customarily traced to three sources: the Harvard-based human relations school, the Weberian tradition descending from Parsons through Merton at Columbia, and the more formal and economic approach associated with March and Simon at Carnegie Tech. Omitted from these lineages is the dominant body of sociological thinking in the inter-war period, the Chicago School. To be sure, organizations play a small role in the canonical image of Chicago sociology. This absence did not involve any lack of interest in social organization more broadly, about which the Chicagoans wrote a great deal. But by ‘social organization’ they meant ‘the organizing of social life’: a gerund rather than a noun, a process rather than a thing. The study of fixed pieces of social structure such as bureaucracies and other formally enacted groups was not for the Chicagoans a separately delineated body of inquiry. This article first sketches the Chicago School and the organizational world it confronted. It then turns to social and formal organization as they actually appear in the Chicagoans' writings. It closes with a discussion of the lessons organization theory today might take from the Chicago sociological tradition.
The Columbia School and the Study of Bureaucracies
Authors: Haveman Heather A.
Published: September 2009

This article focuses on the work of three scholars, Robert K. Merton and his students Alvin W. Gouldner and Peter M. Blau, who were part of Columbia University's sociology department, Merton as professor, Gouldner and Blau as students. Together with Philip Selznick, Seymour Martin Lipset, James Coleman, and Martin Trow, these scholars were the core of the Columbia School of organizational sociology. Along with sociologists and political scientists scattered across America and Europe who studied public administration, and sociology and business professors at Harvard who studied industrial organization, these Columbia sociologists pioneered the sociological study of organizations.
Pastoral Tradition in Religious Poetry
Authors: Scott David
Published: September 2009

The common threads that run through this article are poetry, the ministry of the church, and pastoral consciousness. The ministry of the church could seem to be quite a narrowing of the field, but here denotes that specificity in poetry which comes from those who have a relationship with God, are committed to the Christian church, and who write poetry in English from that standpoint. This article also considers the church's ministry among people and not specifically with the poetry of hymnody, liturgy, or sermons. A pastoral consciousness refines that concept of ministry even more, and is related to the way in which the church engages with people at the level of pastoral care. This is poetry that emerges from the challenge of caring for people in their need; need which is physical and spiritual, and goes some way to being met by visiting, listening, comforting, counselling, and healing.
Entrepreneurship, Technology and Schumpeterian Innovation: Entrants and Incumbents
Authors: Berchicci Luca , Tucci Christopher L.
Published: September 2009

This article reviews the literature on the (lack of) innovativeness of incumbents both in creating new products and entering new markets. It then presents some non-anecdotal evidence as counter-argument to the alleged curse of incumbency. First, it uses as illustration a cross-sectional study by Chandy and Tellis of a large number of radical product innovations. Secondly, it explores to what extent the story of incumbents' inability to enter new markets matches the history of the computer rigid hard drive industry. This industry is particularly suited to this analysis since its technological generational changes have been described by scholars as ‘radical’ and ‘disruptive,’ and because its history served to inspire Christensen's recent theories.
Habitual Entrepreneurs
Authors: Ucbasaran Deniz , Westhead Paul , Wright Mike
Published: September 2009

Entrepreneurial behaviour is increasingly recognized as being heterogeneous. One notable source of heterogeneity is variations in the level and nature of entrepreneurs' experience. This has led to the distinction between experienced (‘habitual’) entrepreneurs and first-time (‘novice’) entrepreneurs. A number of high profile entrepreneurs have successfully owned several businesses. These individuals are known as habitual entrepreneurs, to reflect their ownership in more than one business, either sequentially (i.e. serial entrepreneurs) or concurrently (i.e. portfolio entrepreneurs). Although habitual entrepreneurs are widespread and have received media attention, there has been limited conceptual and theoretical understanding of this group. This article seeks to address this void by utilizing human capital theory to provide a framework for studying habitual entrepreneurs.
Justice After Rawls
Authors: Arneson Richard
Published: September 2009

This article examines the changes in the conception of justice after John Rawls. It explains that Rawls single-handedly revived Anglo-American political philosophy and his theory consists in an egalitarian vision of justice. It discusses criticisms on Rawls' theory of justice and identifies some alternative paths. It suggests that while Rawls' book The Law of Peoples adopted a conservative and somewhat anti-cosmopolitan stance, the doctrine of egalitarianism within national borders and minimal duties across borders may ultimately prove to be unstable under examination.
Emergency Powers
Authors: Ferejohn John , Pasquino Pasquale
Published: September 2009

This article describes the main conceptual questions entailed in the doctrine of emergency powers, taking into account the theory and experience of their enforcement. It explains the constitutional aspects of emergency powers and evaluates the possibility of thinking about the position and force emergency powers play within a polyarchical constitution. It also discusses the epistemic dimension of emergency powers, constitutional dualism, and judicial control over emergency power.
Equality and Difference
Authors: Squires Judith
Published: September 2009

This article examines the contemporary debate concerning the issues of equality and difference. It suggests that equality now appears, in both policy and theory debates, to require a respect for difference rather than a search for similarities. It argues that equality is increasingly theorized as an issue of maldistribution, oppression, and domination. It explains that while liberal egalitarianism focuses primarily on maldistribution, and a politics of recognition addresses cultural oppression, theories of democratic inclusion engage with the need to eradicate domination.
Identity, Difference, Toleration
Authors: Elisabetta Galeotti Anna
Published: September 2009

This article thinks about the relation among identity, difference, and toleration in the context of political theory. It analyses the connections between ways of considering differences and corresponding views of toleration. It identifies the four different conceptions of toleration will: the view of tolerance as a moral virtue, tolerance as recognition, and two liberal views of toleration according to perfectionist and neutralist perspectives. The article suggests that the toleration as recognition view acknowledges differences as features of collective identity.
Politicizing the Body: Property, Contract, and Rights
Authors: Gatens Moira
Published: September 2009

This article examines the politicization of the human body focusing on the way this issue was conceived in the West. The human body has long been used as a source of metaphor for political theorists and the very notion of body politic leans on the image of a unified and discrete entity that has commanding parts and obeying parts that may be robust or ailing, strong or weak. This article suggests that aside from political theory with a rich source of metaphor, the human body also serves as the nexus where political conceptions of the universal and the particular meet.
New Ways of Thinking about Privacy
Authors: Roessler Beate
Published: September 2009

This article examines the new conceptualizing and thinking about privacy. It discusses older theories of privacy and explains why they became obsolete. It suggests that the reconceptualization of privacy was influenced by the developments in information technologies, radical changes in the relation between the sexes, and the intrusion of intimacy into the public realm. It describes the normative problems associated with privacy and differentiates the three dimensions of privacy: decisional privacy, informational privacy, and local privacy.
Development of Civil Society
Authors: Harris Jose
Published: September 2009

This article studies the development of civil society, starting from the end of the Roman Republic until modern times. It identifies four traditions of writing about civil society. This article determines that civil society remains to be a curiously obtuse, malleable, and much contested idea that is difficult to define categorically, by reference to either what it is or what it is not. It also shows that due to the gradual build-up of diverse meanings over the centuries, it is impossible to treat civil society as a Weberian ‘ideal type’.
Executives—The American Presidency
Authors: Howell William G.
Published: September 2009

This article provides a survey of the state of quantitative research on the presidency twenty-five years after Edwards issued his original entreaty. It briefly documents the publication trends on quantitative research on the presidency that has been found by a variety of professionals. This is followed by a review of the contributions of selected quantitative studies to long-standing debates about the centralization of presidential policy-making, presidential authority, and public appeals. This article focuses on the ways recent scholarship addresses methodological issues that regularly affect studies of the organization of political institutions, their interactions with the public, and their influence in systems of separated powers.
Executives In Parliamentary Government
Authors: Rhodes R. A. W.
Published: September 2009

This article examines the executives in parliamentary government, starting with existing approaches to executive government. These include modernist-empiricism, Westminster, rational choice institutionalism, and core executive. The next section looks at the core debates and challenges in the study of parliamentary executives, such as the Commonwealth, Britain, and Western Europe. The next sections cover their executive coordination, the presidentialization of prime ministers, policy capacity, comparative analysis of parliamentary government, and policy advice.
Electoral Systems
Authors: Bowler Shaun
Published: September 2009

This article views electoral systems and electoral system change from an institutional perspective. This perspective lends itself to a rational actor framework that highlights the strategic choices made by voters and political elites. This article has a central organizing theme, which is the way Duverger's Law can be taken to be the canonical statement of what electoral systems (as institutions) do and why the choice of electoral institutions is important. It discusses the changes in electoral systems and even the remarkable lack of change in electoral systems worldwide.
International Economic Institutions
Authors: Martin Lisa L.
Published: September 2009

This article focuses on international economic institutions, particularly on institutions that structure trade and financial relationships. It considers the General Agreement on Tariffs and Trade (GATT) and the World Trade Organization (WTO), regional trade organizations, and the Bretton Woods institutions. The article provides some background information on the study of institutions, generally in international relations. It also focuses on trade organizations and international financial institutions.
About Institutions, Mainly, but not Exclusively, Political
Authors: Blondel Jean
Published: September 2009

This article discusses the concept of institution by examining the components of an institution and the way in which institutionalization can increase or decrease. It considers the place to be given to organizations and to procedures based on the definition of institutions. It reveals the major differences across the social sciences and in particular political, social, and economic fields. The article is also concerned with institutionalization, and reveals marked differences among the social sciences.
Thinking Institutionally
Authors: Heclo Hugh
Published: September 2009

This article studies how to think institutionally. It examines what this particular line of thinking means, and sketches the coherence and significance of mental life inside any and all such institutions. The second half of the article is focused on determining why thinking institutionally is important.
Political Institutions—Old and New
Authors: von Beyme Klaus
Published: September 2009

This article discusses the old and new political institutions. It begins with a study of the transformation from old institutions to new institutions; it is noted that there are a few ‘new institutions’ that developed in the three waves of democratization. The article also examines the evolution of the theories of institutions. The discussion shows that institutions develop less quickly than theories on institutions. ‘Historical institutions’ even demonstrate that institutional traditions are not easy to change.
Paths of Economic and Political Development
Authors: Acemoğlu Daron , Robinson James A.
Published: September 2009

This article develops a simple theoretical framework for combining the study of political and economic development. It applies this framework in the development of a theory of the creation and merging of democracy. The concept of comparative statics is discussed, along with an in-depth case study that shows the theory in action.
Trade, Immigration, and Cross‐Border Investment
Authors: Rogowski Ronald
Published: September 2009

This article discusses the implications of four models related to trade, immigration, and cross-border investment. These four models are: Hecksher-Ohlin, Samuelson-Jones and Ricardo-Viner, neo-Ricardian, and Economies of Scale. The first three models assume constant returns to scale, but all models make the conventional assumption of diminishing marginal returns to any individual factor. The article discusses each model in detail, focusing on trade in products and cross-border migration and investment.
Economic Methods in Positive Political Theory
Authors: Austen-Smith David
Published: September 2009

This article focuses on economic methods in political science, specifically on positive political theory. It provides a sketch of the two canonical approaches to developing a positive political theory: collective preference theory and game theory. It is argued that these two techniques are distinguished by their trade-offs, despite having some clear formal differences. The article also considers other specific techniques within the game-theoretic approach, which are designed to accommodate two important analytical characteristics that are distinctive to political science.
What is Missing from Political Economy
Authors: North Douglass C.
Published: September 2009

This article discusses what is missing from the literature on political economy. The first section discusses the need for a dynamic theory, which is illustrated in three examples provided in the latter portion of the article. It then examines the centrality of beliefs and argues that the failure to understand some fundamental questions reflects that social science fails to have a truly dynamic theory that considers the non-ergodic nature of the world.
Modeling Party Competition in General Elections
Authors: Roemer John E.
Published: September 2009

This article provides a report on the attempts to reproduce political equilibrium among parties and its applications. It examines a review of the two main theories of political competition, and notes the problems that are involved in generalizing these theories to the multidimensional context. It also proposes a resolution to these problems, specifically a theory of multidimensional political competition. The article ends with a discussion of some applications of this theory.
Legal Perspectives
Authors: Alvarez José E.
Published: September 2009

This article provides a summary of the author's writing and teaching at several well-known law schools. The article addresses how the international organizations with a global reach have changed the mechanisms and reasoning behind the making, implementation, and enforcement of international law. It also notes the disappearance of a rather religious faith in law and multilateral approaches that had become characteristic of the legal culture among those who helped design the world organization in the 1940s.
Bretton Woods Institutions
Authors: Woods Ngaire
Published: September 2009

This article discusses the Bretton Woods Institutions, which are often described as the ‘sister institutions’ of the United Nations. It explains how the World Bank and the International Monetary Fund (IMF) generated heated debate and criticism, most especially over the past twenty years. It shows what the institutions do and determines why they have become controversial. The article also identifies the two key factors that limit the effectiveness of the institutions.
Adenosine: An Old Drug Newly Discovered
Authors: Eltzschig Holger K. , Warner David S. , Warner Mark A.
Published: September 2009

Over decades, anesthesiologists have used intravenous adenosine as mainstay therapy for diagnosing or treating supraventricular tachycardia in the perioperative setting. More recently, specific adenosine receptor therapeutics or gene-targeted mice deficient in extracellular adenosine production or individual adenosine receptors became available. These models enabled physicians and scientists to learn more about the biologic functions of extracellular nucleotide metabolism and adenosine signaling. Such functions include specific signaling effects through adenosine receptors expressed by many mammalian tissues; for example, vascular endothelia, myocytes, hepatocytes, intestinal epithelia, or immune cells. At present, pharmacological approaches to modulate extracellular adenosine signaling are evaluated for their potential use in perioperative medicine, including attenuation of acute lung injury; renal, intestinal, hepatic and myocardial ischemia; or vascular leakage. If these laboratory studies can be translated into clinical practice, adenosine receptor-based therapeutics may become an integral pharmacological component of daily anesthesiology practice.
Uncalibrated Stroke Volume Variations Are Able to Predict the Hemodynamic Effects of Positive End-Expiratory Pressure in Patients with Acute Lung Injury or Acute Respiratory Distress Syndrome after Liver Transplantation
Authors: Biais Matthieu , Nouette-Gaulain Karine , Quinart Alice , Roullet Stéphanie , Revel Philippe , Sztark François
Published: September 2009

Background

Positive end-expiratory pressure (PEEP) may reduce cardiac output and total hepatic blood flow after liver transplantation. Pulse pressure variation is useful in predicting the PEEP-induced decrease in cardiac output. The aim of the study was to examine the relationships between stroke volume variations (SVV) obtained with the Vigileo monitor (Edwards Lifesciences, Irvine, CA), and the hemodynamic effects of PEEP.

Methods

Over 2 yr, patients presenting an acute lung injury or an acute respiratory distress syndrome in the 72 h after liver transplantation were prospectively enrolled. Patients were monitored with a pulmonary artery catheter (stroke volume) and with the Vigileo system (stroke volume and SVV). Measurements were performed in duplicate, first during zero end-expiratory pressure and then 10 min after the addition of 10 cm H2O PEEP.

Results

Twenty-six patients were included. Six patients were excluded from analysis. On PEEP, SVV and pulse pressure variation increased significantly and stroke volume decreased significantly. PEEP-induced changes in stroke volume measured by pulmonary artery catheter were significantly correlated with SVV (r = 0.69; P < 0.001) and pulse pressure variation on zero end-expiratory pressure (r = 0.66, P < 0.001). PEEP-induced decrease in stroke volume measured by pulmonary artery catheter > or = 15% was predicted by an SVV > 7% (sensitivity = 100%, specificity = 80%) and by a pulse pressure variation > 8% (sensitivity = 80%, specificity = 100%). PEEP-induced changes in stroke volume measured by pulmonary artery catheter and Vigileo device were correlated (r = 0.51, P < 0.005).

Conclusions

SVV obtained with Vigileo monitor is useful to predict decrease in stroke volume induced by PEEP. Moreover, this device is able to track changes in stroke volume induced by PEEP.
Nitrous Oxide Plus Isoflurane Induces Apoptosis and Increases β-Amyloid Protein Levels
Authors: Zhen Yu , Dong Yuanlin , Wu Xu , Xu Zhipeng , Lu Yan , Zhang Yiying , Norton David , Tian Ming , Li Shuren , Xie Zhongcong
Published: September 2009

Background

Some anesthetics have been suggested to induce neurotoxicity, including promotion of Alzheimer's disease neuropathogenesis. Nitrous oxide and isoflurane are common anesthetics. The authors set out to assess the effects of nitrous oxide and/or isoflurane on apoptosis and beta-amyloid (Abeta) levels in H4 human neuroglioma cells and primary neurons from naïve mice.

Methods

The cells or neurons were exposed to 70% nitrous oxide and/or 1% isoflurane for 6 h. The cells or neurons and conditioned media were harvested at the end of the treatment. Caspase-3 activation, apoptosis, processing of amyloid precursor protein, and Abeta levels were determined.

Results

Treatment with a combination of 70% nitrous oxide and 1% isoflurane for 6 h induced caspase-3 activation and apoptosis in H4 naïve cells and primary neurons from naïve mice. The 70% nitrous oxide plus 1% isoflurane, but neither alone, for 6 h induced caspase-3 activation and apoptosis, and increased levels of beta-site amyloid precursor protein-cleaving enzyme and Abeta in H4-amyloid precursor protein cells. In addition, the nitrous oxide plus isoflurane-induced Abeta generation was reduced by a broad caspase inhibitor, Z-VAD. Finally, the nitrous oxide plus isoflurane-induced caspase-3 activation was attenuated by gamma-secretase inhibitor L-685,458, but potentiated by exogenously added Abeta.

Conclusion

These results suggest that the common anesthetics nitrous oxide plus isoflurane may promote neurotoxicity by inducing apoptosis and increasing Abeta levels. The generated Abeta may further potentiate apoptosis to form another round of apoptosis and Abeta generation. More studies, especially the in vivo confirmation of these in vitro findings, are needed.
S(+)-ketamine Effect on Experimental Pain and Cardiac Output
Authors: Sigtermans Marnix , Dahan Albert , Mooren René , Bauer Martin , Kest Benjamin , Sarton Elise , Olofsen Erik
Published: September 2009

Background

Low-dose ketamine behaves as an analgesic in the treatment of acute and chronic pain. To further understand ketamine's therapeutic profile, the authors performed a population pharmacokinetic-pharmacodynamic analysis of the S(+)-ketamine analgesic and nonanalgesic effects in healthy volunteers.

Methods

Ten men and ten women received a 2-h S(+)-ketamine infusion. The infusion was increased at 40 ng/ml per 15 min to reach a maximum of 320 ng/ml. The following measurements were made: arterial plasma S(+)-ketamine and S(+)-norketamine concentrations, heat pain intensity, electrical pain tolerance, drug high, and cardiac output. The data were modeled by using sigmoid Emax models of S(+)-ketamine concentration versus effect and S(+)-ketamine + S(+)-norketamine concentrations versus effect.

Results

Sex differences observed were restricted to pharmacokinetic model parameters, with a 20% greater elimination clearance of S(+)-ketamine and S(+)-norketamine in women resulting in higher drug plasma concentrations in men. S(+)-ketamine produced profound drug high and analgesia with six times greater potency in the heat pain than the electrical pain test. After ketamine-infusion, analgesia rapidly dissipated; in the heat pain test but not the electrical pain test, analgesia was followed by a period of hyperalgesia. Over the dose range tested, ketamine produced a 40-50% increase in cardiac output. A significant consistent contribution of S(+)-norketamine to overall effect was detected for none of the outcome parameters.

Conclusions

S(+)-ketamine displays clinically relevant sex differences in its pharmacokinetics. It is a potent analgesic at already low plasma concentrations, but it is associated with intense side effects.
Hemodynamic Effects of Ephedrine, Phenylephrine, and the Coadministration of Phenylephrine with Oxytocin during Spinal Anesthesia for Elective Cesarean Delivery
Authors: Dyer Robert A. , Reed Anthony R. , van Dyk Dominique , Arcache Michelle J. , Hodges Owen , Lombard Carl J. , Greenwood Jaime , James Michael F.
Published: September 2009

Background

Hemodynamic responses to vasopressors used during spinal anesthesia for elective Cesarean delivery, have not been well described. This study compared the effects of bolus phenylephrine and ephedrine on maternal cardiac output (CO). The hypothesis was that phenylephrine, but not ephedrine, decreases CO when administered in response to hypotension during spinal anesthesia.

Methods

Forty-three patients were randomized to receive 80 microg of phenylephrine or 10 mg of ephedrine. Both pulse wave form analysis and transthoracic bioimpedance changes were used to estimate stroke volume in each patient. Hemodynamic responses to spinal anesthesia and oxytocin were also recorded. A subgroup of 20 patients was randomized to receive oxytocin compared with oxytocin plus 80 microg of phenylephrine after delivery.

Results

Mean CO and maximum absolute response in CO were significantly lower during the 150 s after phenylephrine administration than after ephedrine (6.2 vs. 8.1 l/min, P = 0.001, and 5.2 vs. 9.0 l/min, P < 0.0001, respectively for pulse wave form analysis, and 5.2 vs. 6.3 l/min, P = 0.01 and 4.5 vs. 6.7 l/min, P = 0.0001, respectively for bioimpedance changes). CO changes correlated with heart rate changes. Coadministration of phenylephrine obtunded oxytocin-induced decreases in systemic vascular resistance and increases in heart rate and CO. Trends in CO change were similar using either monitor.

Conclusions

Bolus phenylephrine reduced maternal CO, and decreased CO when compared with ephedrine during elective spinal anesthesia for Cesarean delivery. CO changes correlated with heart rate changes after vasopressor administration, emphasizing the importance of heart rate as a surrogate indicator of CO. Coadministered phenylephrine obtunded hemodynamic responses to oxytocin.
Amnestic Concentrations of Etomidate Modulate GABAA,slowSynaptic Inhibition in Hippocampus
Authors: Dai Shuiping , Perouansky Misha , Pearce Robert A.
Published: September 2009

Background

Gamma-aminobutyric acid type A (GABA(A)) receptor-mediated inhibition in the central nervous system exists in two forms: phasic (inhibitory postsynaptic currents, IPSCs) and tonic (nonsynaptic). Phasic inhibition is further subdivided into fast (GABA(A,fast)) and slow (GABA(A,slow)) IPSCs. By virtue of its dendritic location and kinetics, GABA(A,slow) has been proposed to control synaptic plasticity and memory. Etomidate is a nonbarbiturate, intravenous anesthetic that selectively modulates GABA(A) receptors and produces amnesia at low doses in vivo. This study tested whether correspondingly low concentrations of etomidate in vitro alter GABA(A,fast) and GABA(A,slow) phasic inhibition.

Methods

Electrophysiological recordings were obtained from hippocampal slices prepared from postnatal day 3-8 mice and maintained in organotypic culture for 10-14 days. Etomidate was applied at concentrations corresponding to one-half to four times the half maximal effective concentration that impairs hippocampus-dependent learning and memory--i.e., 0.125-1.0 microm.

Results

Etomidate 0.25 microm (the half maximal effective concentration) doubled the time constant of decay of GABA(A,slow) IPSCs, but it had no detectable effect on GABA(A,fast) IPSCs. Higher concentrations of etomidate had stronger effects on both types of phasic inhibition: 0.5 and 1 microm etomidate prolonged the time constant of decay by 310% and 410% for GABA(A,slow) and by 25% and 78% for GABA(A,fast). Concentrations of etomidate up to 1 microm had no significant effects on the amplitudes of either GABA(A,fast) or GABA(A,slow) IPSCs.

Conclusions

At concentrations that impair hippocampus-dependent memory, etomidate modulates GABA(A,slow) more strongly than GABA(A,fast) IPSCs. Effects of etomidate on GABA(A,slow) IPSCs may contribute to etomidate-induced amnesia.
Epidural Analgesia in the Latent Phase of Labor and the Risk of Cesarean Delivery
Authors: Wang FuZhou , Shen XiaoFeng , Guo XiRong , Peng YuZhu , Gu XiaoQi
Published: September 2009

Background

The optimal timing of epidural analgesia has been a controversial issue, and how early women can benefit from epidural analgesia is still debated. The objective of this trial was to test the hypothesis that patient-controlled epidural analgesia given at cervical dilation of 1.0 cm or more does not increase the risk of prolonged labor or Cesarean delivery.

Methods

After institutional review board approval and patient consent, 12,793 nulliparous patients requesting neuraxial analgesia were enrolled and randomized to an early epidural (cervical dilation at least 1.0 cm) or delayed epidural (cervical dilation at least 4.0 cm) group. A 15-ml epidural analgesic mixture consisting of 0.125% (1.25 mg/ml) ropivacaine plus 0.3 microg/ml sufentanil was given in a single bolus, followed by patient-controlled pump with a 10-ml bolus without background infusion. Repeatable meperidine (25 mg) was prescribed as being the rescue analgesic to patients in the delayed epidural group. The primary outcome was the rate of Cesarean section.

Results

The median diameters of cervical dilation were 1.6 cm and 5.1 cm in the early and delayed epidural groups, respectively (P < 0.0001). The duration of labor from analgesia request to vaginal delivery was equal in both groups (11.3 +/- 4.5 h for early epidural and 11.8 +/- 4.9 h for delayed epidural group women, P = 0.90). No statistically significant difference in the rate of Cesarean section was observed between the two groups on the intention-to-treat analysis (23.2% vs. 22.8% in the early and delayed epidural groups, respectively; P = 0.51).

Conclusions

Epidural analgesia in the latent phase of labor at cervical dilation of 1.0 cm or more does not prolong the progression of labor and does not increase the rate of Cesarean in nulliparous women compared with the delayed analgesia at the cervical dilation of 4.0 cm or more.
γ-Amino Butyric Acid Type A Receptor Mutations at β2N265 Alter Etomidate Efficacy While Preserving Basal and Agonist-dependent Activity
Authors: Desai Rooma , Ruesch Dirk , Forman Stuart A.
Published: September 2009

Background

Etomidate acts at gamma-Aminobutyric acid type A (GABAA) receptors containing beta2 or beta3, but not beta1 subunits. Mutations at beta residue 265 (Ser in beta1; Asn in beta2 or beta3) profoundly affect etomidate sensitivity. Whether these mutations alter etomidate binding remains uncertain.

Methods

Heterologously expressed alpha1beta2gamma2L GABAA receptors and receptors with beta2(N265S) or beta2(N265M) mutations were studied electrophysiologically in both Xenopus oocytes and HEK293 cells. Experiments quantified the impact of beta2N265 mutations or substituting beta1 for beta2 on basal channel activation, GABA EC50, maximal GABA efficacy, etomidate-induced leftward shift in GABA responses, etomidate direct activation, and rapid macrocurrent kinetics. Results were analyzed in the context of an established allosteric co-agonist mechanism.

Results

Mutations produced only small changes in basal channel activity, GABA EC50, maximal GABA efficacy, and macrocurrent kinetics. Relative to wild-type, beta2(N265S) reduced etomidate enhancement of apparent GABA affinity six-fold, and it reduced etomidate direct activation efficacy 14-fold. beta2(N265M) totally eliminated both etomidate modulation of GABA responses and direct channel activation. Mechanism-based analysis showed that the function of both mutants remains consistent with the allosteric co-agonist model and that beta2(N265S) reduced etomidate allosteric efficacy five-fold, whereas etomidate-binding affinity dropped threefold. Experiments swapping beta2 subunits for beta1 indicated that etomidate efficacy is reduced 34-fold, whereas binding affinity drops less than two-fold.

Conclusions

Mutations at beta2N265 profoundly alter etomidate sensitivity with only small changes in basal and GABA-dependent channel activity. Mutations at the beta2N265 residue or replacement of beta2 with beta1 influence etomidate efficacy much more than binding to inactive receptors.
Mortality Associated with Implantation and Management of Intrathecal Opioid Drug Infusion Systems to Treat Noncancer Pain
Authors: Coffey Robert J. , Owens Mary L. , Broste Steven K. , Dubois Michel Y. , Ferrante F Michael , Schultz David M. , Stearns Lisa J. , Turner Michael S.
Published: September 2009

Background

In 2006, the authors observed a cluster of three deaths, which circumstances suggested were opioid-related, within 1 day after placement of intrathecal opioid pumps for noncancer pain. Further investigation suggested that mortality among such patients was higher than previously appreciated. The authors performed investigations to quantify that mortality and compare the results to control populations, including spinal cord stimulation and low back surgery.

Methods

After analyzing nine index cases--three sentinel cases and six identified by a prospective strategy--the authors used epidemiological methods to investigate whether mortality rates reflected patient- or therapy-related differences. Mortality rates after intrathecal opioid therapy and spinal cord stimulation were derived by correlating Medtronic device registration data with de-identified data from the Social Security Death Master File. Aggregate demographic and comorbidity data were obtained from Medicare and United Healthcare population databases to examine the influence of demographics and comorbidities on mortality.

Results

Device registration and Social Security analyses revealed an intrathecal opioid therapy mortality rate of 0.088% at 3 days after implantation, 0.39% at 1 month, and 3.89% at 1 yr-a higher mortality than after spinal cord stimulation implants or after lumbar diskectomy in community hospitals. Demographic, illness profile, and mortality analyses of large databases suggest, despite limitations, that excess mortality was related to intrathecal opioid therapy, and could not be fully explained by other factors. These findings were consistent with the nine index cases that revealed that respiratory arrest caused or contributed to death in all patients. No device malfunctions associated with overinfusion were identified among cases where data were available.

Conclusions

Patients with noncancer pain treated with intrathecal opioid therapy experience increased mortality compared to similar patients treated by using other therapies. Respiratory depression as a consequence of intrathecal drug overdosage or mixed intrathecal and systemic drug interactions is one plausible, but hypothetical mechanism. The exact causes for patient deaths and the proportion of those deaths attributable to intrathecal opioid therapy remain to be determined. These findings, although based on incomplete information, suggest that it may be possible to reduce mortality in noncancer intrathecal opioid therapy patients.
Operation Timing Does Not Affect Outcome after Coronary Artery Bypass Graft Surgery
Authors: Tan Paul J. , Xu Meng , Sessler Daniel I. , Bashour C Allen
Published: September 2009

Background

Human factors such as fatigue, circadian rhythms, scheduling, and staffing may have an impact on patient care over the course of a day across all medical specialties. Research by the transportation industry concludes that human performance is degraded by shift work, circadian rhythm disturbances, and prolonged duty. This study investigated whether the timing of coronary artery bypass graft surgery affects outcomes.

Methods

The outcomes of coronary artery bypass graft surgery patients were analyzed according to the hour of the day, day of the workweek, month, and moon phase in which the surgery started. All patients who underwent isolated coronary artery bypass graft surgery between January 1, 1993 and July 1, 2006 were considered for the study.The primary outcome measurement was a compound morbidity outcome of six variables defined by the Society of Thoracic Surgeons. These outcomes included (1) in-hospital death, (2) acute postoperative myocardial infarction, (3) neurologic morbidity, including focal or global neurologic deficits or death without awakening, (4) serious infection morbidity consisting of sepsis syndrome or septic shock, (5) new-onset renal failure requiring dialysis, and (6) postoperative ventilatory support exceeding 72 h.

Results

The composite morbidity and in-hospital mortality rates were 4.8% and 1.4%, respectively. The number of cases each weekday, each month of the year, and during each phase of the moon were consistent. None of the time factors significantly affected the composite morbidity outcome.

Conclusions

Elective coronary artery bypass graft surgery can be scheduled throughout the workday, any day of the work week and in any month of the year without compromising outcome.
Effect of β-blocker Prescription on the Incidence of Postoperative Myocardial Infarction after Hip and Knee Arthroplasty
Authors: van Klei Wilton A. , Bryson Gregory L. , Yang Homer , Forster Alan J.
Published: September 2009

Background

American College of Cardiology/American Heart Association guidelines recommend beta-blockade for selected low- and intermediate-risk noncardiac surgery patients. The authors evaluated the effect of perioperative beta-blockade on postoperative myocardial infarction (POMI) in low-risk patients undergoing intermediate-risk surgery.

Methods

Patients who underwent elective hip or knee arthroplasty between January 1, 2002 and June 30, 2006 were identified. POMI was defined as a Troponin T value of more than 0.1 ng . ml(-1). Patients were divided into three groups: those prescribed a beta-blocker on the day of surgery and throughout their hospital stay (or 7 days, whichever came first), those prescribed a beta-blocker on the day of surgery but discontinued during the first 7 days, and those not prescribed a beta-blocker on the day of surgery. Propensity analysis and logistic regression were used to determine the independent association of beta-blocker exposure on POMI.

Results

Of the 5,158 arthroplasty patients, 992 (18%) were treated with beta-blockers on the day of surgery. This beta-blocker was discontinued in 252 patients (25%). POMI occurred in 77 patients (1.5%). Discontinuation of beta-blocker prescription was significantly associated with POMI (odds ratio 2.0; 95% CI 1.1-3.9) and death (odds ratio 2.0; 95% CI 1.0-3.9).

Conclusion

After adjustment for confounders, discontinuation of beta-blocker prescription during the first week after surgery was significantly associated with POMI and death. These findings confirm the American College of Cardiology/American Heart Association Guidelines on Perioperative Cardiovascular Evaluation and Care for Noncardiac Surgery, which recommend not to withdraw beta-blocker therapy.
Mechanical Ventilation Induces a Toll/Interleukin-1 Receptor Domain-containing Adapter-inducing Interferon β–dependent Inflammatory Response in Healthy Mice
Authors: Vaneker Michiel , Heunks Leo M. A. , Joosten Leo A. , van Hees Hieronymus W. H. , Snijdelaar Dirk G. , Halbertsma Feico J. , van Egmond Jan , Netea Mihai G. , van der Hoeven Johannes G. , Scheffer Gert Jan
Published: September 2009

Background

Mechanical ventilation (MV) can induce lung injury. Proinflammatory cytokines have been shown to play an important role in the development of ventilator-induced lung injury. Previously, the authors have shown a role for Toll-like receptor 4 signaling. The current study aims to investigate the role of Toll/interleukin-1 receptor domain-containing adapter-inducing interferon-beta (TRIF), a protein downstream of Toll-like receptors, in the development of the inflammatory response after MV in healthy mice.

Methods

Wild-type C57BL6 and TRIF mutant mice were mechanically ventilated for 4 h. Lung tissue and plasma was used to investigate changes in cytokine profile, leukocyte influx, and nuclear factor-kappaB activity. In addition, experiments were performed to assess the role of TRIF in changes in cardiopulmonary physiology after MV.

Results

MV significantly increased messenger RNA expression of interleukin (IL)-1beta in wild-type mice, but not in TRIF mutant mice. In lung homogenates, MV increased levels of IL-1alpha, IL-1beta, and keratinocyte-derived chemokine in wild-type mice. In contrast, in TRIF mutant mice, only a minor increase in IL-1beta and keratinocyte-derived chemokine was found after MV. Nuclear factor-kappaB activity after MV was significantly lower in TRIF mutant mice compared with wild-type mice. In plasma, MV increased levels of IL-6 and keratinocyte-derived chemokine. In TRIF mutant mice, no increase of IL-6 was found after MV, and the increase in keratinocyte-derived chemokine appeared less pronounced. TRIF deletion did not affect cardiopulmonary physiology after MV.

Conclusions

The current study supports a prominent role for TRIF in the development of the pulmonary and systemic inflammatory response after MV.