bluuebunny/crossref_metadata_2025 huggingface dataset:
Circadian change of cardiac autonomic function in correlation with intra‐esophageal pH
Authors: Lee Yi‐Chia , Wang Hsiu‐Po , Lin Lian‐Yu , Chuang Kai‐Jen , Chiu Han‐Mo , Wu Ming‐Shiang , Chen Ming‐Fong , Lin Jaw‐Town
Published: March 2006

Background and Aim:  Although autonomic alterations are observed in patients with gastroesophageal reflux disease (GERD), the influence of visceral receptor responses on the dynamics of autonomic function remains unknown. The aim of this study was to investigate the autonomic functional changes in association with intra‐esophageal pH under ambulation.

Methods:  Thirty patients referred for 48 h ambulatory pH monitoring underwent simultaneous 24 h cardiac monitoring for heart rate variability (HRV). We used linear mixed‐effects models to estimate the relationship between esophageal acid exposure and power spectral analysis of HRV, including low‐frequency power (0.04 < LF < 0.15 Hz), high‐frequency power (0.15 < or = HF < 0.4 Hz), and LF/HF power ratio.

Results:  Over the 24‐h period, patients with pathological reflux had lower average LF and HF powers than patients with functional heartburn, but the LF/HF power ratios were similar for the two patient groups. As we stratified the data according to waking and sleeping times, a significantly higher HF power but lower LF/HF power ratio was found during sleeping time regardless of diagnosis. In the regression analysis, esophageal pH was positively associated with change (not basal tone) of both LF and HF powers during waking, but only with change of HF power during sleeping time. The significant associations between pH values and changes in HRV decreased gradually with time. The LF/HF power ratio did not alter significantly with pH.

Conclusion:  Esophageal acid exposure is generally associated with decreases in autonomic tone. A predominant parasympathetic fluctuation during sleeping and a superimposed sympathetic interaction during waking dictate diurnal characteristics of autonomic regulation.
Prevalence of irritable bowel syndrome in Korea: Population‐based survey using the Rome II criteria
Authors: Han Sung Hee , Lee Oh Young , Bae Sang Cheol , Lee Seok Hwa , Chang Yu Kyung , Yang Sun Young , Yoon Byung Chul , Choi Ho Soon , Hahm Joon Soo , Lee Min Ho , Lee Dong Hoo , Kim Tae Hwa
Published: March 2006

Background:  Irritable bowel syndrome (IBS) is a common functional gastrointestinal disorder in the West. But information on the prevalence of IBS in Asia is still lacking, especially in Korea. Therefore, the aims of the present study were to estimate the prevalence of IBS in the general population of Korea and also to investigate characteristics of IBS and health‐care‐seeking behavior of IBS patients.

Methods:  Telephone interview survey was conducted by Gallup, Korea using a validated questionnaire based on the Rome II criteria. The response rate of the telephone interview survey was 25.2% (n = 1066, 535 male and 531 female responders). A random sample of gender and age (between 18 and 60 years), based on a per capita ratio was obtained.

Results:  Among 1066 subjects, the prevalence of IBS was 6.6% (70 subjects; 7.1%, male; 6.0%, female). The difference in IBS prevalence by gender was not significant. The prevalence was higher among those in their 20s (P = 0.036). Among 70 subjects with IBS, 10/20 IBS subjects sought health care due to abdominal pain. Among the risk factors of IBS, marital status had a significant difference; the following risk factors are arranged in descending order: age (odds ratio [OR]: 1.38, 95% confidence interval [CI]: 0.85–2.25), alcohol intake (OR: 1.38, 95%CI: 0.81–2.35), gender (OR: 1.19, 95%CI: 0.73–1.94), demographics (OR: 1.09, 95%CI: 0.53–2.25), income (OR: 0.88, 95%CI: 0.54–1.45), education level (OR: 0.81, 95%CI: 0.46–1.40), smoking (OR: 0.64, 95%CI: 0.37–1.12), and marital status (OR: 0.59, 95%CI: 0.35–0.99).

Conclusions:  The prevalence of IBS in the Korean population is 6.6%, and the male : female ratio is similar. Also, IBS is more frequent in younger subjects. Irritable bowel syndrome subjects visited a physician mostly due to abdominal pain.
Silent myocardial ischemia in coronary artery disease patients under aspirin therapy presenting with upper gastrointestinal hemorrhage
Authors: Chen Chien‐Chih , Chong Chee‐Fah , Kuo Cheng‐Deng , Wang Tzong‐Luen
Published: March 2006

Aim:  To identify the risk factors for myocardial ischemia in patients undergoing aspirin therapy for coronary artery disease (CAD) presenting with upper gastrointestinal hemorrhage and to ascertain the impacts on mortality and length of hospital stay.

Methods:  Adults with CAD under aspirin therapy (100 mg once daily) presenting to the emergency department with upper gastrointestinal hemorrhage were retrospectively recruited and divided into group A (ischemia) and group B (non‐ischemia). Charts were reviewed for various demographic, laboratory and outcome data. Electrocardiograms were interpreted blindly by a senior cardiologist.

Results:  A total of 152 patients, 72.4% men and 27.6% women, were analyzed. Of these, 31 patients had ischemia and were placed in group A and 121 patients did not have ischemia and were in group B. Independent multivariate predictors of myocardial ischemia were history of triple vessel disease (odds ratio [OR], 9.24; 95% confidence interval [CI], 2.00–42.72), lower diastolic blood pressure (OR, 1.09; 95% CI, 1.02–1.16), lower hematocrit (OR, 1.41; 95% CI, 1.16–1.70), and higher blood urea nitrogen (OR, 0.94; 95% CI, 0.89–0.98). Patients with myocardial ischemia had significantly longer hospital length of stay (8.7 ± 4.0 days vs 5.4 ± 1.7 days; P < 0.001) and higher in‐hospital mortality (16.1%vs 2.5%; P < 0.01) than did those without myocardial ischemia.

Conclusion:  Myocardial ischemia is a relatively common complication in CAD patients under aspirin therapy presenting with upper gastrointestinal hemorrhage. A history of CAD with triple vessel disease, higher blood urea nitrogen, lower diastolic blood pressure and lower hematocrit may help identify patients who are at increased risk of myocardial ischemia, which tends to be associated with higher in‐hospital mortality and increased length of hospital stay.
Influences of Helicobacter pylori on cyclooxygenase‐2 expression and prostaglandinE2 synthesis in rat gastric epithelial cells in vitro
Authors: Shen Hong , Sun Wei‐Hao , Xue Qi‐Ping , Wu Jing , Cheng Yun‐Lin , Ding Guo‐Xian , Fu Hai‐Ying , Tsuji Shingo , Kawano Sunao
Published: March 2006

Background and Aim:  It is known that cyclooxygenase (COX)‐2 is over expressed in gastrointestinal neoplasia and Helicobacter pylori (H. pylori) infection is causally linked to gastric cancer. The present study aimed to elucidate the effects of H. pylori on COX‐2 expression and prostaglandinE2 (PGE2) production in a gastric epithelial cell line derived from normal rat gastric mucosa (RGM1).

Method:  H. pylori water extracts were prepared from a supernatant of the H. pylori suspension in distilled water. RGM1 cells were cultured with H. pylori water extracts at the final concentration of 2.5, 5, 10 µg/mL for 24 h. For the time sequence study, RGM1 cells were cultured with 10 µg/mL H. pylori water extracts for 0, 6, 12, 24 and 48 h. COX‐1 and COX‐2 expression in the RGM1 cells was analyzed by western blotting. The levels of PGE2 in the cultured media were measured by enzyme immunoassay.

Results:  H. pylori did not affect COX‐1 expression; whereas COX‐2 expression increased by six‐fold at 24 h after incubation of RGM1 cells with 10 µg/mL H. pylori water extracts. The increase in COX‐2 expression was evident after 12 h of incubation; reached a peak at 24 h and declined at 48 h. H. pylori dose dependently increased COX‐2 expression and PGE2 synthesis in RGM1 cells.

Conclusion:  H. pylori induces COX‐2 expression and increases PGE2 synthesis in RGM1 cells in vitro. These results indicate that H. pylori‐associated gastric carcinogenesis may depend on COX‐2 expression.
Constipation of anorectal outlet obstruction: Pathophysiology, evaluation and management
Authors: Andromanakos Nikolaos , Skandalakis Panayiotis , Troupis Theodoros , Filippou Dimitrios
Published: March 2006

Constipation is a subjective symptom of various pathological conditions. Incidence of constipation fluctuates from 2 to 30% in the general population. Approximately 50% of constipated patients referred to tertiary care centers have obstructed defecation constipation. Constipation of obstructed defecation may be due to mechanical causes or functional disorders of the anorectal region. Mechanical causes are related to morphological abnormalities of the anorectum (megarectum, rectal prolapse, rectocele, enterocele, neoplasms, stenosis). Functional disorders are associated with neurological disorders and dysfunction of the pelvic floor muscles or anorectal muscles (anismus, descending perineum syndrome, Hirschsprung's disease). However, this type of constipation should be differentiated by colonic slow transit constipation which, if coexists, should be managed to a second time. Assessment of patients with severe constipation includes a good history, physical examination and specialized investigations (colonic transit time, anorectal manometry, rectal balloon expulsion test, defecography, electromyography), which contribute to the diagnosis and the differential diagnosis of the cause of the obstructed defecation. Thereby, constipated patients can be given appropriate treatment for their problem, which may be conservative (bulk agents, high‐fiber diet or laxatives), biofeedback training or surgery.
Nicotine exposure in vivo induces long‐lasting enhancement of NMDA receptor‐mediated currents in the hippocampus
Authors: Yamazaki Yoshihiko , Jia Yousheng , Niu Rong , Sumikawa Katumi
Published: March 2006

The use of nicotine via cigarette smoking forms long‐lasting memories that are recalled in response to environmental cues associated with previous nicotine use. However, the changes in brain memory systems that underlie these long‐lasting memories are not well understood. The N‐methyl‐d‐aspartate receptor (NMDAR) is critical for long‐lasting modifications of synapses. Here we show that in vivo nicotine exposure induces the enhancement of NR2B‐containing NMDAR‐mediated currents in the hippocampus, a brain region associated with the formation of memories. This nicotine effect is maintained during continued nicotine exposure and is accompanied by increased tyrosine phosphorylation of NR2B. Furthermore, long‐term potentiation (LTP), which is considered to be a cellular substrate of learning and memory, induced in nicotine‐exposed hippocampi contains a protein synthesis‐independent long‐lasting component. An NR2B‐selective antagonist blocks a long‐lasting component of LTP, but not LTP. These results suggest that exposure to nicotine provides conditions that promote the induction of long‐lasting modifications of synapses, which may be involved in the formation of memories involving nicotine use.
Spillover edge effects: the dispersal of agriculturally subsidized insect natural enemies into adjacent natural habitats
Authors: Rand Tatyana A. , Tylianakis Jason M. , Tscharntke Teja
Published: March 2006

The cross‐edge spillover of subsidized predators from anthropogenic to natural habitats is an important process affecting wildlife, especially bird, populations in fragmented landscapes. However, the importance of the spillover of insect natural enemies from agricultural to natural habitats is unknown, despite the abundance of studies examining movement in the opposite direction. Here, we synthesize studies from various ecological sub‐disciplines to suggest that spillover of agriculturally subsidized insect natural enemies may be an important process affecting prey populations in natural habitat fragments. This contention is based on (1) the ubiquity of agricultural–natural edges in human dominated landscapes; (2) the substantial literature illustrating that crop and natural habitats share important insect predators; and (3) the clear importance of the landscape matrix, specifically distance to ecological edges, in influencing predator impacts in agroecosystems. Further support emerges from theory on the importance of cross‐boundary subsidies for within site consumer–resource dynamics. In particular, high productivity and temporally variable resource abundance in agricultural systems are predicted to result in strong spillover effects. More empirical work examining the prevalence and significance of such natural enemy spillover will be critical to a broader understanding of fragmentation impacts on insect predator–prey interactions.
VALUATION OF FLOATING RANGE NOTES IN LÉVY TERM‐STRUCTURE MODELS
Authors: Eberlein Ernst , Kluge Wolfgang
Published: March 2006

Turnbull (1995) as well as Navatte and Quittard‐Pinon (1999) derived explicit pricing formulae for digital options and range notes in a one‐factor Gaussian Heath–Jarrow–Morton (henceforth HJM) model. Nunes (2004) extended their results to a multifactor Gaussian HJM framework. In this paper, we generalize these results by providing explicit pricing solutions for digital options and range notes in the multivariate Lévy term‐structure model of Eberlein and Raible (1999), that is, an HJM‐type model driven by a d‐dimensional (possibly nonhomogeneous) Lévy process. As a byproduct, we obtain a pricing formula for floating range notes in the special case of a multifactor Gaussian HJM model that is simpler than the one provided by Nunes (2004).
NONPARAMETRIC KERNEL‐BASED SEQUENTIAL INVESTMENT STRATEGIES
Authors: Györfi László , Lugosi Gábor , Udina Frederic
Published: March 2006

The purpose of this paper is to introduce sequential investment strategies that guarantee an optimal rate of growth of the capital, under minimal assumptions on the behavior of the market. The new strategies are analyzed both theoretically and empirically. The theoretical results show that the asymptotic rate of growth matches the optimal one that one could achieve with a full knowledge of the statistical properties of the underlying process generating the market, under the only assumption that the market is stationary and ergodic. The empirical results show that the performance of the proposed investment strategies measured on pastnyseand currency exchange data is solid, and sometimes even spectacular.
OPTIMAL STATIC–DYNAMIC HEDGES FOR BARRIER OPTIONS
Authors: İlhan Aytaç , Sircar Ronnie
Published: March 2006

We study optimal hedging of barrier options, using a combination of a static position in vanilla options and dynamic trading of the underlying asset. The problem reduces to computing the Fenchel–Legendre transform of the utility‐indifference price as a function of the number of vanilla options used to hedge. Using the well‐known duality between exponential utility and relative entropy, we provide a new characterization of the indifference price in terms of the minimal entropy measure, and give conditions guaranteeing differentiability and strict convexity in the hedging quantity, and hence a unique solution to the hedging problem. We discuss computational approaches within the context of Markovian stochastic volatility models.
PORTFOLIO INSURANCE AND VOLATILITY REGIME SWITCHING
Authors: Vanden Joel M.
Published: March 2006

A new equilibrium model of portfolio insurance is presented in order to study the volatility effects of dynamic insurance strategies. While prior research has focused on the relationship between portfolio insurance and the overall level of market volatility, this article shows that the salient feature of portfolio insurance is volatility regime switching. Regime switching is shown to be a necessary condition for portfolio insurance, which provides a new explanation for the pervasive volatility clustering effect that is found in most equity markets. The equilibrium involves a free boundary and the local time of the equilibrium price process at the free boundary plays an important role in solving the model.
DISTRIBUTION‐INVARIANT RISK MEASURES, INFORMATION, AND DYNAMIC CONSISTENCY
Authors: Weber Stefan
Published: March 2006

In the first part of the paper, we characterize distribution‐invariant risk measures with convex acceptance and rejection sets on the level of distributions. It is shown that these risk measures are closely related to utility‐based shortfall risk.

In the second part of the paper, we provide an axiomatic characterization for distribution‐invariant dynamic risk measures of terminal payments. We prove a representation theorem and investigate the relation to static risk measures. A key insight of the paper is that dynamic consistency and the notion of “measure convex sets of probability measures” are intimately related. This result implies that under weak conditions dynamically consistent dynamic risk measures can be represented by static utility‐based shortfall risk.
UNIFORM TECHNICAL PROGRESS: CAN IT BE HARMFUL?
Authors: Beladi Hamid , Marjit Sugata , Oladi Reza
Published: March 2006

Abstract.  In a model incorporating trade in final goods, intermediate goods and capital, we show how ‘uniform’ technical progress across sectors can lead to immiserization. The condition for immiserizing technical progress crucially depends on the pattern of specialization. Our results tend to hold in a more general specification of the basic structure.
FACTOR ACCUMULATION OR TFP? A REASSESSMENT OF GROWTH IN SOUTHEAST ASIA
Authors: Grosskopf Shawna , Self Sharmistha
Published: March 2006

Abstract.  This paper reassesses economic growth in five South‐East Asian countries utilizing a non‐parametric productivity index and parametric techniques to trace the ultimate source/s of growth. Our results show that there is no single explanation for the growth performance of the countries in our sample. The results, particularly with reference to the role of embodied technology are comforting in terms of policy implications for countries such as Singapore, where, given the capital output ratios, there are lower returns to future capital accumulation. The possibility of capital being embodied through technological change makes future prospects much brighter for such a country.
WELFARE EFFECTS OF TECHNOLOGY TRANSFER
Authors: Takarada Yasuhiro
Published: March 2006

Abstract.  This paper examines the welfare effects of aid tied to technology transfer in a two‐country general equilibrium model. In the recipient country, some factors of production employed in a particular industry are difficult to use in other industries because their properties are specific to that industry. Technology transfer facilitates ‘factor movement’ and improves the efficiency of factor markets in the recipient. We identify and interpret the conditions under which technology transfer benefits the recipient and harms the donor. We also show that technology transfer can enrich (or harm) both the donor and the recipient under certain conditions.
INFLOW OF FOREIGN CAPITAL AND TRADE LIBERALIZATION IN A MODEL WITH AN INFORMAL SECTOR AND URBAN UNEMPLOYMENT
Authors: Chaudhuri Sarbajit , Yabuuchi Shigemi , Mukhopadhyay Ujjaini
Published: March 2006

Abstract. The paper has made an attempt to analyse the effects of liberalized trade and investment policies on welfare and open unemployment in a developing economy in terms of a three sector Harris‐Todaro type general equilibrium model. Following empirical evidence it is assumed that there is wage rigidity in urban sectors, which leads to the simultaneous existence of open unemployment and an urban informal sector in the migration equilibrium. The paper deserves special attention for its interesting results which are completely opposite to those generated by the standard Harris‐Todaro model.
Dealing with Uncertainty: Managing Personal Investment in the Early English National Debt
Authors: MURPHY ANNE L.
Published: March 2006

During the late seventeenth century there was a ‘Financial Revolution’ in England. Prompted by the exigencies of the Nine Years War (1689–97), the state marked the beginnings of a permanently funded National Debt by introducing a series of measures, the most important of which was the foundation of the Bank of England in 1694. The state's financial innovations were enthusiastically supported by London's business community and also attracted the capital and the trust of investors of more limited means and financial knowledge. Through the surviving papers of Samuel Jeake, a merchant from the East Sussex town of Rye, this article considers the strategies used by those less prominent investors, and examines the methods they used to obtain financial information and the costs they faced. Jeake's experiences reveal much about the factors that led ordinary investors to commit their capital to the newly established public funds but show that, during the formative period of the Financial Revolution, the costs of placing faith in the state's financial promises often outweighed the benefits.
Mutational Spectrum and Linkage Disequilibrium Patterns at the Ornithine Transcarbamylase Gene (OTC)
Authors: Azevedo L. , Soares P. A. , Quental R. , Vilarinho L. , Teles E. L. , Martins E. , Diogo L. , Garcia P. , Cenni B. , Wermuth B. , Amorim A.
Published: March 2006

Ornithine transcarbamylase (OTC; EC 2.1.3.3) is a hepatic enzyme involved in ammonia elimination via the urea cycle. Since the sequence of the OTC gene was reported many types of mutations continue to be found in OTC deficiency patients, continuing to increase the already wide mutational spectrum known for this gene. In this study we present the clinical, biochemical and molecular features of thirteen late‐onset OTC deficiency patients. Mutations were identified in all these patients, among which six were novel point substitutions (L59R, A137P, L148S, Y176L, L186P, and K210N) and one was a 2‐bp deletion at exon 4 (341‐342delAA). In addition, a de novo genomic deletion of maternal origin encompassing exons 1 to 5 was also identified by the analysis of LD patterns using intragenic polymorphic markers. This work exemplifies the potential value of population genetic studies for the detection of large deletions.
Standardized Subsets of the HGDP‐CEPH Human Genome Diversity Cell Line Panel, Accounting for Atypical and Duplicated Samples and Pairs of Close Relatives
Authors: Rosenberg Noah A.
Published: March 2006

The HGDP‐CEPH Human Genome Diversity Cell Line Panel is a widely‐used resource for studies of human genetic variation. Here, pairs of close relatives that have been included in the panel are identified. Together with information on atypical and duplicated samples, the inferred relative pairs suggest standardized subsets of the panel for use in future population‐genetic studies.
The Genetic Structure of Human Populations Studied Through Short Insertion‐Deletion Polymorphisms
Authors: Bastos‐Rodrigues Luciana , Pimenta Juliana R. , Pena Sergio D. J.
Published: March 2006

In a landmark study Rosenberg et al. (2002) analyzed human genome diversity with 377 microsatellites in the HGDP‐CEPH Genome Diversity Panel and reported that the populations were structured into five geographical regions: America, Sub‐Saharan Africa, East Asia, Oceania and a cluster composed of Europe, the Middle East and Central Asia. They also observed that the within‐population component accounted for 93–95%, and that the among‐regions portion was only 3.6%, of the total genetic variance. We have also studied the HGDP‐CEPH Diversity Panel (1064 individuals from 52 populations) with a set of 40 biallelic slow‐evolving short insertion‐deletion polymorphisms (indels). We confirmed the partition of worldwide diversity into five genetic clusters that correspond to major geographic regions. Using the indels we have also disclosed an among‐regions component of genetic variance considerably larger (12.1%) than had been estimated using microsatellites. Our study demonstrates that a set of 40 well‐chosen biallelic markers is sufficient for the characterization of human population structure at the global level.
The historiography of nationalism and national identity in Latin America
Authors: MILLER NICOLA
Published: March 2006

ABSTRACT.This article surveys the current state of research on nationalism in Latin America, focusing on the large body of work produced from the 1990s onwards in a wide variety of disciplines (history, the social sciences and cultural studies). Covering work on both the nineteenth and the twentieth centuries, it takes as a starting point the impact of Benedict Anderson's work,Imagined Communities, on Latin Americanists. It discusses the ways in which Latin Americanists have applied his ideas, and their critiques of many of his claims about Latin American nationalism. It goes on to outline major recent developments across the field, within the context of an argument that it is important for all scholars of nationalism to incorporate Latin American experiences into their debates on the history and theory of nationalism. The references have been selected to guide readers to key relevant works; regrettably, the article cannot, for reasons of space, offer a fully comprehensive bibliography.
Not forging nations but foraging for them: uncertain collective identities in Gran Colombia*
Authors: BROWN MATTHEW
Published: March 2006

ABSTRACT.This article examines the place of the nation in discussions of collective identities in the early nineteenth century in northern Hispanic South America. It provides a historical account of the birth of national identities in the late colonial and early republican period, and then explores two main sections. The first looks at the port of Riohacha and its experiences during the Wars of Independence. The second examines the in‐patients at a hospital in Caracas just after the end of the wars in 1821. The conclusion suggests that foreign involvement in the Wars of Independence was a crucial catalyst to national identity formation in Gran Colombia. As such the article brings out the extent to which these wars were part of Atlantic networks which were being reconfigured during the Age of Revolution. Rather than forging national identities, the Wars of Independence were the arena in which elites foraged for the constituents of new states and nations.
Visual culture in Brazil's First Republic (1889–1930): allegories and elite discourse
Authors: SALGUEIRO VALÉRIA
Published: March 2006

ABSTRACT. The research on which the present work is based analyses the ornamentation of the façades of major Brazilian public buildings and investigates how that representation contributed to the construction of a visual national identity during Brazil's First Republic (1889–1930). Two government buildings are discussed: Pedro Ernesto Palace, inaugurated in 1923 to house the municipal chamber of Rio de Janeiro, and Tiradentes Palace, erected in the years 1922–26 to house Brazil's Parliament. The article focuses on the allegorical figures ornamenting these two buildings in order to explore contradictory aspects of the discourse they convey. It will be argued that visual culture, more precisely architecture and architectural sculpture, served the elites of this period as a powerful tool for projecting their values and for preventing contradictions within Brazilian society from emerging in visual terms.
A new Mexican nationalism? Indigenous rights, constitutional reform and the conflicting meanings of multiculturalism*
Authors: DE LA PEÑA GUILLERMO
Published: March 2006

ABSTRACT.This article focuses on the recent Mexican controversy about the legal status of the indigenous population and the nature of nationalism, which is linked to recent constitutional amendments and new policy strategies. Changes in legislation and policy are examined in the context of a widespread economic and political crisis of the populist regime after 1982, which radically affected the previous indigenist discourse; but they are also seen as having been motivated by Indian demands and mobilisations against the official vision of citizenship as a function of cultural homogeneity andmestizaje. The article analyses the implications of the new constitutional amendments and the heated debates that they have provoked among different political actors, including indigenous organisations. In particular, it examines two areas of disagreement. The first concerns the multiple meanings of multiculturalism – as a threat of fragmentation and fundamentalism, a new form of state control or a strategy for indigenous national participation and empowerment. The second concerns the definition and levels of implementation of indigenous political autonomy. Negotiation over such disagreements, leading to inclusive citizenship, constitute a great challenge for ethnic intellectuals and theoreticians of Mexican nationalism.
Changes in Chilean identity: thirty years after the military coup
Authors: LARRAIN JORGE
Published: March 2006

ABSTRACT.The objective of this article is to explore whether events, starting with the 1973 military coup and ocurring during the seventeen‐year‐long dictatorship, have caused or influenced important changes in the Chilean national identity. After a brief theoretical discussion, an analysis is made of the upheavals that occurred in Chile during the last thirty years seeking to assess what tensions they have introduced within Chilean identity. As a consequence some changes are detected which can be seen at the level of public discourses on Chilean identity with the emergence or rekindling of military‐racial, Catholic and entrepreneurial narratives. But the most important change that Chilean identity has suffered has to do with the development of an internal fracture stemming from the division introduced by the military regime. In so far as the contents of identity are concerned, the article focuses on the decline in acknowledgement of shared symbols of the nation, the persistence of a pervasive collective anxiety, a recurrence of belief in Chilean exceptionalism, and fading respect for politicians and democracy. These aspects are oddly coupled with rising belief in voluntarism and the possibility of sustained economic growth, increased resort to the market rather than political life as the site of recognition, acceptance of malaise as the price of economic progress and a remarkable centrality of human rights issues.
Patriotic thoughts or intuition: roles of women in Mexican nationalisms*
Authors: CHONG NATIVIDAD GUTIÉRREZ
Published: March 2006

ABSTRACT.This article presents a methodological exercise for the study of women in the nationalisms implied in the making of the Mexican nation. Bearing in mind the body of literature produced from an historical perspective, we have identified three types of nationalisms: the wars of independence, the nation‐building process and the multicultural nation. After discussing each type, the strategy proposed would apply the typology of women's roles and intersections of nationalism (Nira Yuval‐Davis and Floya Anthias). Such combined typologies allow us to identify the multiple interactions of women and the nation. We have empirically recourse to two characterisations of women: as heroines, and as intellectual creators of the nation. By looking at the role played by these female characters we observe how nationalism interacts with the current of ideas, thoughts or intuitions held by women.
Post‐translational regulation of EAAT2 function by co‐expressed ubiquitin ligase Nedd4‐2 is impacted by SGK kinases
Authors: Boehmer Christoph , Palmada Monica , Rajamanickam Jeyaganesh , Schniepp Roman , Amara Susan , Lang Florian
Published: March 2006

The human excitatory amino acid transporter (EAAT)2 is the major glutamate carrier in the mammalian CNS. Defective expression of the transporter results in neuroexcitotoxicity that may contribute to neuronal disorders such as amyotrophic lateral sclerosis (ALS). The serum and glucocorticoid inducible kinase (SGK) 1 is expressed in the brain and is known to interact with the ubiquitin ligase Nedd4‐2 to modulate membrane transporters and ion channels. The present study aimed to investigate whether SGK isoforms and the related kinase, protein kinase B (PKB), regulate EAAT2. Expression studies in Xenopus oocytes demonstrated that glutamate‐induced inward current (IGLU) was stimulated by co‐expression of SGK1, SGK2, SGK3 or PKB. IGLU is virtually abolished by Nedd4‐2, an effect abrogated by additional co‐expression of either kinase. The kinases diminish the effect through Nedd4‐2 phosphorylation without altering Nedd4‐2 protein abundance. SGKs increase the transporter maximal velocity without significantly affecting substrate affinity. Similar to glutamate‐induced currents, [3H] glutamate uptake and cell surface abundance of the transporter were increased by the SGK isoforms and down‐regulated by the ubiquitin ligase Nedd4‐2. In conclusion, all three SGK isoforms and PKB increase EAAT2 activity and plasma membrane expression and thus, may participate in the regulation of neuroexcitability.
Granulocyte‐colony stimulating factor is neuroprotective in a model of Parkinson's disease
Authors: Meuer Katrin , Pitzer Claudia , Teismann Peter , Krüger Carola , Göricke Bettina , Laage Rico , Lingor Paul , Peters Kerstin , Schlachetzki Johannes C. M. , Kobayashi Kazuto , Dietz Gunnar P. H. , Weber Daniela , Ferger Boris , Schäbitz Wolf‐Rüdiger , Bach Alfred , Schulz Jörg B. , Bähr Mathias , Schneider Armin , Weishaupt Jochen H.
Published: March 2006

We have recently shown that the hematopoietic Granulocyte‐Colony Stimulating Factor (G‐CSF) is neuroprotective in rodent stroke models, and that this action appears to be mediated via a neuronal G‐CSF receptor. Here, we report that the G‐CSF receptor is expressed in rodent dopaminergic substantia nigra neurons, suggesting that G‐CSF might be neuroprotective for dopaminergic neurons and a candidate molecule for the treatment of Parkinson's disease. Thus, we investigated protective effects of G‐CSF in 1‐methyl‐4‐phenylpyridinium (MPP+)‐challenged PC12 cells and primary neuronal midbrain cultures, as well as in the mouse 1‐methyl‐4‐phenyl‐1,2,3,6‐tetrahydropyridine (MPTP) model of Parkinson's disease. Substantial protection was found against MPP+‐induced dopaminergic cell death in vitro. Moreover, subcutaneous application of G‐CSF at a dose of 40 μg/Kg body weight daily over 13 days rescued dopaminergic substantia nigra neurons from MPTP‐induced death in aged mice, as shown by quantification of tyrosine hydroxylase‐positive substantia nigra cells. Using HPLC, a corresponding reduction in striatal dopamine depletion after MPTP application was observed in G‐CSF‐treated mice. Thus our data suggest that G‐CSF is a novel therapeutic opportunity for the treatment of Parkinson's disease, because it is well‐tolerated and already approved for the treatment of neutropenic conditions in humans.
Maturation and maintenance of cholinergic medial septum neurons require glucocorticoid receptor signaling
Authors: Guijarro Christian , Rutz Susanne , Rothmaier Katharina , Turiault Marc , Zhi Qixia , Naumann Thomas , Frotscher Michael , Tronche Francois , Jackisch Rolf , Kretz Oliver
Published: March 2006

Glucocorticoids have been shown to influence trophic processes in the nervous system. In particular, they seem to be important for the development of cholinergic neurons in various brain regions. Here, we applied a genetic approach to investigate the role of the glucocorticoid receptor (GR) on the maturation and maintenance of cholinergic medial septal neurons between P15 and one year of age by using a mouse model carrying a CNS‐specific conditional inactivation of the GR gene (GRNesCre). The number of choline acetyltransferase and p75NTR immuno‐positive neurons in the medial septum (MS) was analyzed by stereology in controls versus mutants. In addition, cholinergic fiber density, acetylcholine release and cholinergic key enzyme activity of these neurons were determined in the hippocampus. We found that in GRNesCre animals the number of medial septal cholinergic neurons was significantly reduced during development. In addition, cholinergic cell number further decreased with aging in these mutants. The functional GR gene is therefore required for the proper maturation and maintenance of medial septal cholinergic neurons. However, the loss of cholinergic neurons in the medial septum is not accompanied by a loss of functional cholinergic parameters of these neurons in their target region, the hippocampus. This pinpoints to plasticity of the septo‐hippocampal system, that seems to compensate for the septal cell loss by sprouting of the remaining neurons.
Regulation of astrocytic glutamate transporter expression by Akt: evidence for a selective transcriptional effect on the GLT‐1/EAAT2 subtype
Authors: Li Li‐Bin , Toan Shuy Vang , Zelenaia Olga , Watson Deborah J. , Wolfe John H. , Rothstein Jeffrey D. , Robinson Michael B.
Published: March 2006

In the nervous system, astrocytes express different ratios of the two glial glutamate transporters, glutamate transporter subtype 1 (GLT‐1) and glutamate/aspartate transporter (GLAST), but little is known about the signaling pathways that independently regulate their expression. Treatment with dibutyryl‐cAMP, epidermal growth factor (EGF) or other growth factors both induces expression of GLT‐1 and increases expression of GLAST in astrocyte cultures. The induction of GLT‐1 is correlated with morphological and biochemical changes that are consistent with astrocyte maturation. Pharmacological studies suggest that phosphatidylinositol 3‐kinase (PI‐3K) and the nuclear transcription factor‐κB (NF‐κB) may be involved in the induction of GLT‐1 expression. In several signaling systems Akt, also known as protein kinase B (PKB), functions downstream of PI‐3K. In these present studies we used lentiviral vectors engineered to express dominant‐negative (DN), constitutively active (CA), or null variants of Akt to study the possible involvement of Akt in the regulation of GLT‐1. Expression of DN‐Akt attenuated the EGF‐dependent induction of GLT‐1. Expression of CA‐Akt caused a dose‐ and time‐dependent increase in GLT‐1 protein, increased GLT‐1 mRNA levels, increased dihydrokainate‐sensitive (presumably GLT‐1 mediated) transport activity, and caused a change in astrocyte morphology to a more stellate shape, but had no effect on GLAST protein levels. Finally, the expression of CA‐Akt increased the expression of a reporter construct containing a putative promoter fragment from the human homolog of GLT‐1, called EAAT2. From these studies, we conclude that Akt induces the expression of GLT‐1 through increased transcription and that Akt can regulate GLT‐1 expression without increasing GLAST expression in astrocytes.
Dopamine release is severely compromised in the R6/2 mouse model of Huntington's disease
Authors: Johnson Michael A. , Rajan Vignesh , Miller Charles E. , Wightman R. Mark
Published: March 2006

Recently, alterations in dopamine signaling have been implicated in Huntington's disease. In this work, dopamine release and uptake was measured in striatal slices from the R6/2 transgenic mouse model of Huntington's disease using fast‐scan cyclic voltammetry at carbon‐fiber microelectrodes. Dopamine release in brain slices from 6‐week‐old R6/2 mice is substantially reduced (53% of wild type), while dopamine uptake is unaffected. In agreement with this, R6/2 mice injected with the dopamine uptake inhibitor cocaine exhibited a blunted motor activity response (54% of wild type). At 10 weeks of age, an even more dramatic motor activity decrease in response to cocaine injection (21% of wild type) was observed. Moreover, the pre‐drug activity of 10‐week‐old R6/2 mice was significantly reduced (by 37%) compared with 6‐week‐old R6/2 mice. Striatal dopamine release decreased with age, indicating that progressive alterations in dopaminergic pathways may affect motor activity. The inhibition constants of cocaine and methamphetamine (METH) determined in brain slices differed little between genotype or age group, suggesting that the decreased responses to cocaine and METH arise from compromised dopamine release rather than differences in uptake or drug action. Collectively, these data demonstrate (i) a reduction in the ability of dopamine terminals to release dopamine and (ii) the importance of this attenuation of release on the motor symptoms of Huntington's disease.
Translational event mediates differential production of tumor necrosis factor‐α in hyaluronan‐stimulated microglia and macrophages
Authors: Wang Mei‐Jen , Kuo Jon‐Son , Lee Wen‐Wen , Huang Hsin‐Yi , Chen Wu‐Fu , Lin Shinn‐Zong
Published: March 2006

Recent evidence has demonstrated that hyaluronan synthase 2 mRNA is up‐regulated after brain ischemia. After a cerebral ischemic event, microglia and macrophages are the major inflammatory cells and are activated by hyaluronan (HA). However, it is unclear how these cells compare with regard to HA responsiveness. We show here that peritoneal macrophages and RAW 264.7 macrophages produced more than five‐ and 10‐fold more tumor necrosis factor‐α (TNF‐α) than primary microglia and BV‐2 microglia, respectively. Antibody blockade study showed that CD44, Toll‐like receptor‐4 receptor and the receptor for HA‐mediated motility were responsible for HA‐induced TNF‐α release. Furthermore, HA induced higher levels of phosphorylated MAPK in RAW 264.7 cells when compared with BV‐2 cells. HA‐mediated TNF‐α production required p38 MAPK, extracellular‐regulated kinase and c‐Jun N‐terminal kinase phosphorylation in both cell types. The levels of HA‐induced TNF‐α mRNA expression in BV‐2 cells were only twofold lower compared with RAW 264.7 cells, suggesting that a translational event is involved in the differential production of TNF‐α. Western blot analysis revealed that HA treatment resulted in more rapid phosphorylation of eukaryotic initiation factor 4E‐binding protein 1 (4E‐BP1) and more effective dissociation of 4E‐BP1 from eukaryotic initiation factor 4E in RAW 264.7 cells than in BV‐2 cells. Additionally, HA‐induced phosphorylation of 4E‐BP1 was dependent on MAPK signaling, indicating that RAW 264.7 cells exhibited higher levels of hyperphosphorylated 4E‐BP1 possibly due to the overactivation of MAPK. The results suggest that resident microglia and blood‐derived monocytes/macrophages exhibit differential sensitivities in response to extracellular mediators after brain ischemia.
Differential metabolic adaptation to acute and long‐term hypoxia in rat primary cortical astrocytes
Authors: Véga Céline , R. Sachleben Leroy , Gozal David , Gozal Evelyne
Published: March 2006

Brain astrocytes provide structural and metabolic support to surrounding cells during ischemia. Glucose and oxygen are critical to brain function, and glucose uptake and metabolism by astrocytes are essential to their metabolic coupling to neurons. To examine astrocyte metabolic response to hypoxia, cell survival and metabolic parameters were assessed in rat primary cortical astrocytes cultured for 3 weeks in either normoxia or in either 1 day or 3 weeks sustained hypoxia (5% O2). Although cell survival and proliferation were not affected by the mildly hypoxic environment, substantial differences in glucose consumption and lactate release after either acute or prolonged hypoxia suggest that astrocyte metabolism may contribute to their adaptation. Hypoxia over a period of 1 day increased glucose uptake, lactate release, and glucose transporter 1 (GLUT1) and monocarboxylate transporter 1 (MCT1) expression, whereas hypoxia over a period of 3 weeks resulted in a decrease of all parameters. Furthermore, increased glucose uptake at 1 day of hypoxia was not inhibited by cytochalasin B suggesting the involvement of additional glucose transporters. We uncovered hypoxia‐regulated expression of sodium‐dependent glucose transporters (SGLT1) in astrocytes indicating a novel adaptive strategy involving both SGLT1 and GLUT1 to regulate glucose intake in response to hypoxia. Overall, these findings suggest that although increased metabolic response is required for the onset of astrocyte adaptation to hypoxia, prolonged hypoxia requires a shift to an energy conservation mode. These findings may contribute to the understanding of the relative tolerance of astrocytes to hypoxia compared with neurons and provide novel therapeutic strategies aimed at maintaining brain function in cerebral pathologies involving hypoxia.
Chronic depolarization stimulates norepinephrine transporter expression via catecholamines
Authors: Habecker Beth A. , Willison Breanne D. , Shi Xiao , Woodward William R.
Published: March 2006

Chronic depolarization increases norepinephrine (NE) uptake and expression of the norepinephrine transporter (NET) in sympathetic neurons, but the mechanisms are unknown. Depolarization of sympathetic neurons stimulates catecholamine synthesis, and several studies suggest that NET can be regulated by catecholamines. It is not clear if the depolarization‐induced increase in NET is because of nerve activity per se, or is secondary to elevated catecholamines. To determine if induction of NET mRNA was a result of increased catecholamines, we used pharmacological manipulations to (i) inhibit tyrosine hydroxylase activity in neurons depolarized with 30 mmKCl, thereby preventing increased catecholamines, or (ii) stimulate tyrosine hydroxylase activity in the absence of depolarization. Inhibiting the depolarization‐induced increase in catecholamines prevented the up‐regulation of NET mRNA, but did not block the increase in tyrosine hydroxylase (TH) mRNA. Furthermore, stimulating catecholamine production in the absence of depolarization elevated NE uptake, NET protein, and NET mRNA in sympathetic neurons. Similarly, elevating endogenous catecholamines in SK‐N‐BE(2)M17 neuroblastoma cells increased NE uptake and NET expression. These data suggest that chronic depolarization of sympathetic neurons induces NET expression through increasing catecholamines, and that M17 neuroblastoma cells provide a model system in which to investigate catechol regulation of NET expression.
Puromycin‐purified rat brain microvascular endothelial cell cultures exhibit improved barrier properties in response to glucocorticoid induction
Authors: Calabria Anthony R. , Weidenfeller Christian , Jones Angela R. , De Vries Helga E. , Shusta Eric V.
Published: March 2006

In vitro blood–brain barrier (BBB) models using primary rat brain microvessel endothelial cells (BMEC) are often hampered by a lack of culture purity and poor barrier properties. To address these problems, the translation inhibitor puromycin was used to purify rat BMEC cultures. BMEC purities of 99.8% were routinely attained using puromycin treatment, and this technique proved to be far superior to other purification methods of similar difficulty. In contrast to cultures without puromycin treatment, purity of puromycin‐treated cultures was unaffected by initial seeding density. Next, rat BMEC monolayer transendothelial electrical resistance (TEER) was increased by glucocorticoid treatment with either corticosterone (CORT) or hydrocortisone (HC), and a corresponding decrease in monolayer permeability to small molecules was observed. Importantly, cultures treated with both puromycin and glucocorticoid attained significantly higher TEER values (CORT 168 ± 13 Ω × cm2; HC 218 ± 66 Ω × cm2) than those treated by the glucocorticoid alone (CORT 57 ± 5 Ω × cm2; HC 70 ± 2 Ω × cm2). Glucocorticoid induction resulted in BMEC morphological changes that accompanied the increases in TEER, and BMEC tight junctions exhibited improved integrity as visualized by the localization of tight junction proteins zonula occluden‐1, occludin and claudin‐5. The combined use of puromycin and glucocorticoid therefore provides an in vitro system that is well suited for molecular level BBB investigations.