bluuebunny/crossref_metadata_2025 huggingface dataset:
The role of the PDE4D cAMP phosphodiesterase in the regulation of glucagon‐like peptide‐1 release
Authors: Ong WK , Gribble FM , Reimann F , Lynch MJ , Houslay MD , Baillie GS , Furman BL , Pyne NJ
Published: April 2009

Background and purpose:  Increases in intracellular cyclic AMP (cAMP) augment the release/secretion of glucagon‐like peptide‐1 (GLP‐1). As cAMP is hydrolysed by cAMP phosphodiesterases (PDEs), we determined the role of PDEs and particularly PDE4 in regulating GLP‐1 release.

Experimental approach:  GLP‐1 release, PDE expression and activity were investigated using rats and GLUTag cells, a GLP‐1‐releasing cell line. The effects of rolipram, a selective PDE4 inhibitor both in vivo and in vitro and stably overexpressed catalytically inactive PDE4D5 (D556A‐PDE4D5) mutant in vitro on GLP‐1 release were investigated.

Key results:  Rolipram (1.5 mg·kg−1 i.v.) increased plasma GLP‐1 concentrations approximately twofold above controls in anaesthetized rats and enhanced glucose‐induced GLP‐1 release in GLUTag cells (EC50∼1.2 nmol·L−1). PDE4D mRNA transcript and protein were detected in GLUTag cells using RT‐PCR with gene‐specific primers and Western blotting with a specific PDE4D antibody respectively. Moreover, significant PDE activity was inhibited by rolipram in GLUTag cells. A GLUTag cell clone (C1) stably overexpressing the D556A‐PDE4D5 mutant, exhibited elevated intracellular cAMP levels and increased basal and glucose‐induced GLP‐1 release compared with vector‐transfected control cells. A role for intracellular cAMP/PKA in enhancing GLP‐1 release in response to overexpression of D556A‐PDE4D5 mutant was demonstrated by the finding that the PKA inhibitor H89 reduced both basal and glucose‐induced GLP‐1 release by 37% and 39%, respectively, from C1 GLUTag cells.

Conclusions and implications:  PDE4D may play an important role in regulating intracellular cAMP linked to the regulation of GLP‐1 release.

British Journal of Pharmacology (2009) 157, 633–644; doi:10.1111/j.1476‐5381.2009.00194.x; published online 9 April 2009
3′,4′‐Dihydroxyflavonol down‐regulates monocyte chemoattractant protein‐1 in smooth muscle: role of focal adhesion kinase and PDGF receptor signalling
Authors: Jiang F , Guo N , Dusting GJ
Published: April 2009

Background and purpose:  We investigated the effects of a synthetic flavonol, 3′,4′‐dihydroxyflavonol (DiOHF) on the expression of monocyte chemoattractant protein‐1 (MCP‐1) in rat vascular smooth muscle cells.

Experimental approach:  MCP‐1 expression was assessed by quantitative real‐time PCR and protein phosphorylation by immunoprecipitation and Western blots.

Key results:  DiOHF (1–30 µmol·L−1) concentration‐dependently reduced MCP‐1 expression in both quiescent cells and cells stimulated with platelet‐derived growth factor (PDGF) or interleukin 1‐β. The effect of DiOHF was associated with a suppression of focal adhesion kinase (FAK)‐mediated signalling. In vitro kinase assays demonstrated that DiOHF is a potent inhibitor of FAK kinase activity (EC50= 2.4 µmol·L−1). Expression of FAK‐related non‐kinase reduced basal MCP‐1 expression, but not that induced by PDGF or interleukin 1‐β. DiOHF also inhibited autophosphorylation of PDGF receptors. The PDGF receptor inhibitor AG‐1296 potently suppressed basal and PDGF‐induced MCP‐1 expression. Inhibition of extracellular signal‐regulated kinase activation by DiOHF, either directly or indirectly, may also be involved in its effects on MCP‐1 expression. DiOHF had no inhibitory effect on either p38 or nuclear factor‐κB activation. Moreover, DiOHF inhibited smooth muscle cell spreading (a FAK‐mediated response) and proliferation.

Conclusions and implications:  This is the first report on a flavonoid compound (DiOHF) that is a potent FAK inhibitor. DiOHF also inhibits PDGF receptor autophosphorylation. These effects underlie the inhibitory action of DiOHF on MCP‐1 expression in smooth muscle cells. Our results suggest that DiOHF might be a useful tool for dissection of the (patho)physiological roles of FAK signalling.

British Journal of Pharmacology (2009) 157, 597–606; doi:10.1111/j.1476‐5381.2009.00199.x; published online 9 April 2009
Cities vs. agriculture: A review of intersectoral water re‐allocation
Authors: Molle Francois , Berkoff Jeremy
Published: April 2009

Water demand management, or making better use of the water we have — as opposed to augmenting supply — is increasingly proposed as a way of mitigating water‐scarcity problems. Moving water away from agriculture to uses with higher economic value is one of the main measures widely seen as desirable. Sectoral “allocation stress” is seen as resulting from the disproportionate share, and inefficient use of water in the agricultural sector. This apparent misallocation is often attributed to the failure of government to allocate water rationally.

This paper revisits this commonly‐accepted wisdom and examines the nature of urban water scarcity, showing the importance of economic and political factors, shaped by incentives to decision‐makers, and sometimes compounded by climatic conditions. It shows that cities’ growth is not generally constrained by competition with agriculture. In general, rather than using a narrow financial criterion, cities select options that go along the “path of least resistance,” whereby economic, social and political costs are considered in conjunction. The question of allocation stress is thus reframed into an inquiry of how transfers effectively occur and can be made more effective.
Integrated Water Resources Management: From general principles to its implementation by the state. The case of Burkina Faso
Authors: Petit Olivier , Baron Catherine
Published: April 2009

In 2000, the Global Water Partnership (GWP) as the main advocate of the concept of Integrated Water Resources Management (IWRM), proposed a definition that is now the reference, despite the ambiguity that persists in its interpretation. At the 2002 World Summit on Sustainable Development, the State representatives committed themselves to launch “plans for integrated water resources management and water efficiency by 2005”. Some states immediately honoured this commitment by adopting new national water policies inspired by IWRM principles. Do these implementation plans respond to all the challenges of the IWRM? Or have these states simply reorganized their water resource policies to give an impression of conforming to the framework? In response to these questions, we present a history of IWRM and its conflicting interpretations followed by a case study of reforms enacted in Burkina Faso, to highlight some problems which are inherent to IWRM and how IWRM was transposed on a national scale.
Possible mechanisms involved in the discrepancy of hepatic and aortic endothelial nitric oxide synthases during the development of cirrhosis in rats
Authors: Shir Mohammadi Morvarid , Thabut Dominique , Cazals‐Hatem Dominique , Galbois Arnaud , Rudler Marika , Bonnefont‐Rousselot Dominique , Moreau Richard , Lebrec Didier , Tazi Khalid A.
Published: April 2009

Background/Aim: In cirrhosis, systemic nitric oxide (NO) overproduction and hepatic NO hypoproduction lead to arterial vasodilatation and portal hypertension. The mechanisms involved in these alterations in endothelial NO synthase (eNOS)‐derived NO production in hepatic and systemic vasculature remain unknown. The aim of this study was to evaluate the regulation of eNOS and its major modulators in the liver and aorta during the development of cirrhosis in rats.

Methods: Activated eNOS and Akt and expressions, and caveolin‐1 (Cav‐1) and scavenger receptor class B type I (SR‐BI) expressions were measured before and 1, 2, 3 and 4 weeks after bile duct ligation. Plasma high‐density lipoprotein (HDL) levels were measured.

Results: Activated aortic eNOS increased at week 1, whereas it began to decrease at week 3 in the liver. Aortic expression of Cav‐1 decreased at week 3 while hepatic expression increased by four‐fold. Activated aortic Akt increased progressively while in the liver it gradually decreased during the development of cirrhosis. HDL levels decreased during the first week and decreased thereafter. The hepatic expression of SR‐BI decreased.

Conclusion: This study shows that the modulation of Akt and Cav‐1 is inverted in the liver and the aorta during the development of cirrhosis. In addition, decreased HDL levels may play a role in reduced hepatic eNOS activity.
Experience with Cyclosporine in Children with Chronic Idiopathic Urticaria
Authors: Doshi Devang R. , Weinberger Miles M.
Published: April 2009

Abstract:  Background:  The identification of an autoimmune mechanism for many patients with chronic idiopathic urticaria (CIU) was used as a rational for a controlled clinical trial of cyclosporine for adults with CIU not responsive to usual measures. That randomized placebo controlled clinical trial demonstrated clinical efficacy, acceptable safety, and a suggestion of inducing remission in such patients.

Objective:  To report our experience with cyclosporine in pediatric patients with CIU.

Methods:  Fifty‐four patients with CIU were referred to us during the period from 2000 through June of 2005. Seven of those, aged 9–16, failed therapy with high dose antihistamines even with the addition of alternate morning prednisone. Neoral brand of cyclosporine, 3 mg/kg/day divided b.i.d., was initiated in these patients. Cyclosporine serum concentrations, blood urea nitrogen (BUN), creatinine, and blood pressure were routinely monitored.

Results:  All had cessation of hives. This occurred after 1–4 weeks for six of the seven and 8 weeks for one. While some experienced relapses, all were eventually off of all medications and free of hives. None of the seven experienced any adverse effects.

Conclusions:  Our experience in children is consistent with a previous controlled clinical trial in adults and supports the efficacy and safety of cyclosporine for CIU. However, we recommend that it be reserved for those whose CIU that is resistant to conventional measures and that patients be carefully monitored with cyclosporine serum concentrations and measures of renal function.
Facilitation of Myocardial PI3K/Akt/nNOS Signaling Contributes to Ethanol‐Evoked Hypotension in Female Rats
Authors: El‐Mas Mahmoud M. , Fan Ming , Abdel‐Rahman Abdel A.
Published: April 2009

Background: The mechanism by which ethanol reduces cardiac output (CO) and blood pressure (BP) in female rats remains unclear. We tested the hypothesis that enhancement of myocardial phosphatidylinositol 3‐kinase (PI3K)/Akt signaling and related neuronal nitric oxide synthase (nNOS) and/or endothelial nitric oxide synthase (eNOS) activity constitutes a cellular mechanism for the hemodynamic effects of ethanol.

Methods: We measured the level of phosphorylated eNOS (p‐eNOS) and p‐nNOS in the myocardium of ethanol (1 g/kg intragastric, i.g.) treated female rats along with hemodynamic responses [BP, CO, stroke volume, (SV), total peripheral resistance, (TPR)], and myocardial nitrate/nitrite levels (NOx) levels. Further, we investigated the effect of selective pharmacological inhibition of nNOS withNω‐propyl‐l‐arginine (NPLA) or eNOS withN5‐(1‐iminoethyl)‐l‐ornithine (l‐NIO) on cellular, hemodynamic, and biochemical effects of ethanol. The effects of PI3K inhibition by wortmannin on the cardiovascular actions of ethanol and myocardial Akt phosphorylation were also investigated.

Results: The hemodynamic effects of ethanol (reductions in BP, CO, and SV) were associated with significant increases in myocardial NOx and myocardial p‐nNOS and p‐Akt expressions while myocardial p‐eNOS remained unchanged. Prior nNOS inhibition by NPLA (2.5 or 12.5 μg/kg) attenuated hemodynamic effects of ethanol and abrogated associated increases in myocardial NOx and cardiac p‐nNOS contents. The hemodynamic effects of ethanol and increases in myocardial p‐Akt phosphorylation were reduced by wortmannin (15 μg/kg). On the other hand, although eNOS inhibition byl‐NIO (4 or 20 mg/kg) in a dose‐dependent manner attenuated ethanol‐evoked hypotension, the concomitant reductions in CO and SV remained unaltered. Also, selective eNOS inhibition uncovered dramatic increases in TPR in response to ethanol, which appeared to have offset the reduction in CO. Neither NPLA norl‐NIO altered plasma ethanol levels.

Conclusions: These findings implicate the myocardial PI3K/Akt/nNOS signaling in the reductions in BP and CO produced by ethanol in female rats.
Stereotypes, Asian Americans, and Wages: An Empirical Strategy Applied to Computer Use at Work
Authors: Tashiro Sanae , Conrad Cecilia A.
Published: April 2009

Abstract

This article examines the effect on wages of the Asian‐American stereotype as mathematically and technically adept, and the role this stereotype may play in explaining racial wage differences. We propose an empirical strategy to examine the influence of stereotypes on labor market outcomes, with a specific application to the wage premium associated with computer use at work. Using Current Population Survey data, ordinary least squares estimates do not provide compelling evidence that a positive stereotype affects wages for Asian Americans.
Determinants of Intercountry Internet Diffusion Rates
Authors: Wunnava Phanindra V. , Leiter Daniel B.
Published: April 2009

Abstract

This article employs cross‐sectional data from 100 countries to analyze the main determinants of intercountry Internet diffusion rates. We set up an empirical model based on strong theoretical foundations, in which we regress Internet usage on variables that capture social, economic, and political differences between these countries. Our results support past findings that economic strength, infrastructure, and knowledge of the English language positively affect Internet connectivity. In addition to these indicators, the openness of a country, tertiary enrollment, and income equality are found to also have a significant positive effect on Internet diffusion.
College Football and Student Quality: An Advertising Effect or Culture and Tradition?
Authors: Smith D. Randall
Published: April 2009

Abstract

Intercollegiate sports are said to generate positive advertising that produces many benefits to the host school. Donations, applications, and the academic quality of the student body are some of the mission outcomes thought to rise with the fortunes of the football team. The present study tests these claims for three measures of the academic quality of the entering classes on a 12‐year panel of the 233 colleges and universities competing at the highest levels of football. Results show clear positive effects attributable to the football program, though those effects are more the result of the football culture and tradition at the school than the on‐field performance of the team. Any sports advertising effects of the football program are minimal when compared to the effects of nonathletic institutional characteristics on the quality of students enrolling at the school.
Uncertainty and Variability in Health‐Related Damages from Coal‐Fired Power Plants in the United States
Authors: Levy Jonathan I. , Baxter Lisa K. , Schwartz Joel
Published: April 2009

The health‐related damages associated with emissions from coal‐fired power plants can vary greatly across facilities as a function of plant, site, and population characteristics, but the degree of variability and the contributing factors have not been formally evaluated. In this study, we modeled the monetized damages associated with 407 coal‐fired power plants in the United States, focusing on premature mortality from fine particulate matter (PM2.5). We applied a reduced‐form chemistry‐transport model accounting for primary PM2.5 emissions and the influence of sulfur dioxide (SO2) and nitrogen oxide (NOx) emissions on secondary particulate formation. Outputs were linked with a concentration‐response function for PM2.5‐related mortality that incorporated nonlinearities and model uncertainty. We valued mortality with a value of statistical life approach, characterizing and propagating uncertainties in all model elements. At the median of the plant‐specific uncertainty distributions, damages across plants ranged from $30,000 to $500,000 per ton of PM2.5, $6,000 to $50,000 per ton of SO2, $500 to $15,000 per ton of NOx, and $0.02 to $1.57 per kilowatt‐hour of electricity generated. Variability in damages per ton of emissions was almost entirely explained by population exposure per unit emissions (intake fraction), which itself was related to atmospheric conditions and the population size at various distances from the power plant. Variability in damages per kilowatt‐hour was highly correlated with SO2 emissions, related to fuel and control technology characteristics, but was also correlated with atmospheric conditions and population size at various distances. Our findings emphasize that control strategies that consider variability in damages across facilities would yield more efficient outcomes.
Public Perceptions of Florida Red Tide Risks
Authors: Kuhar Sara E. , Nierenberg Kate , Kirkpatrick Barbara , Tobin Graham A.
Published: April 2009

This research integrates theoretical frameworks of risk perception, social amplification of risk, and the role of place‐specific contexts in order to explore the various perceptions surrounding Florida red tides. Florida red tides are naturally occurring events that are increasing in frequency, duration, and severity. This has implications for public health, the local economy, and ecosystem health. While many of the negative impacts of Florida red tides are not easily controlled, some of the secondary impacts may be mitigated through individuals' responses. However, public perception and consequent reactions to Florida red tides have not been investigated. This research uses questionnaire surveys, and semi‐structured interviews, to explore the various perceptions of the risk surrounding red tides. Surveys and interviews were conducted along two Florida west coast beaches. The results indicate that the underlying foundations of the social amplification of the risk framework are applicable to understanding how individuals form perceptions of risk relative to red tide events. There are key differences between the spatial locations of individuals and corresponding perceptions, indicating that place‐specific contexts are essential to understanding how individuals receive and interpret risk information. The results also suggest that individuals may be lacking efficient and up‐to‐date information about Florida red tides and their impacts because of inconsistent public outreach. Overall, social and spatial factors appear to be influential as to whether individuals amplify or attenuate the risks associated with Florida red tides.
Ethical Considerations of the Legitimacy Lie
Authors: Rutherford Matthew W. , Buller Paul F. , Stebbins J. Michael
Published: April 2009

This article draws upon prior research and theory on the legitimacy threshold that suggests entrepreneurs in start–up ventures will likely employ proactive strategies to gain initial legitimacy with key stakeholders. We argue that these strategies may sometimes include questionable ethical behaviors, including telling legitimacy lies—intentional misrepresentations of the facts. Based on a review of literature on ethical decision making, we then apply two common ethical frameworks to explore the ethical boundaries of what may or may not be acceptable behavior in seeking legitimacy. We conclude the article with some specific guidelines for start–up entrepreneurs.
Dielectric Properties of the Bi(1.6−0.8x)YxTi2O(6.4+0.3x) (0.03<x<2) Pyrochlore Solid Solution
Authors: Kunej Špela , Suvorov Danilo
Published: April 2009

We have studied the dielectric properties of a new, cubic pyrochlore‐type solid solution Bi(1.6−0.8x)YxTi2O(6.4+0.3x) (0.03<x<2). The single‐phase nature of the pyrochlore solid solution was determined using X‐ray diffraction and scanning electron microscopy. We found that at room temperature and 1 MHz the pyrochlore solid solution exhibited values of the dielectric constant ɛ between 127 and 64, and low dielectric losses, tan δ, of <6 × 10−3. The temperature coefficient of the dielectric constant τk is, however, strongly dependent on the composition. Below room temperature dielectric relaxation phenomena were observed for the compositions with low x values.
To Be a Donor or Not to Be? Applying an Extended Theory of Planned Behavior to Predict Posthumous Organ Donation Intentions
Authors: Hyde Melissa K. , White Katherine M.
Published: April 2009

Using a theory of planned behavior (TPB) perspective, individual intentions to register and discuss the decision of organ donation with significant others were examined. In addition to standard TPB variables (attitude, subjective norm, and perceived behavioral control [PBC]), self‐identity and moral norm were incorporated into the TPB as predictors. Australian university students (N = 303) completed a survey comprising standard and additional TPB constructs. Separate analyses were conducted for both registered and nonregistered participants. In general, results provide support for the extended TPB model in predicting intentions to register and discuss the donation decision, with the exceptions that self‐identity did not predict discussion intentions for either registered or nonregistered participants, and PBC did not predict discussion intentions for nonregistered participants.
Getting the Job: Attributional Retraining and the Employment Interview1
Authors: Jackson Shannan E. , Hall Nathan C. , Rowe Patricia M. , Daniels Lia M.
Published: April 2009

This study examined the effectiveness of attributional retraining (AR) in an employment interview setting. Our sample consisted of 50 co‐operative education students completing job interviews who were randomly assigned to a control or writing‐based AR condition. Dependent measures included attributions, expectations, and affect, as well as behavior with respect to an interview skills workshop, and actual employment outcomes. Results showed AR to promote controllable failure attributions, expectations, motivated behavior, and interview success, particularly among participants with maladaptive baseline attributions. Findings further revealed AR effects on emotions mediated by post‐treatment attributions. Implications for attribution theory and research on AR in employment settings are discussed.
High Frequency AC Power System
Authors: CALFO RAYMOND M. , POOLE GREGORY E. , TESSARO JOHN E.
Published: April 2009

The Navy's Next Generation Integrated Power System (NGIPS) master plan calls for the evolution of the IPS system from its current medium voltage, 60 Hz state to a high‐frequency, medium‐voltage AC (HFAC) system in the next 10 years. Beyond that, and pending development of key protection components, a medium‐voltage DC system will be considered for implementation. The master plan calls for power generation modules at three power levels across these systems:

A low power level (2–5 MW) driven by a fuel‐efficient diesel prime mover,

A medium power level (10–15 MW) driven by a gas turbine, and

A main propulsion power level (20–40 MW) driven by a gas turbine.

EMD is currently developing a high‐speed, high‐frequency, liquid‐cooled generator under contract with NAVSEA that will effectively demonstrate the mid‐level generator for the HFAC system. It will be coupled directly to the output of a GE LM1600 Gas Turbine to provide a TG set with power density four times more favorable than conventional ATG sets. The generator development is proceeding favorably, with testing at the Navy's land‐based test site (LBTS) expected to begin in July 2008. The technology embodied in the high‐speed generator can be easily extrapolated to main turbine generator power levels. Given the availability of prime movers at appropriate speeds, the power generation modules for the HFAC system, at all three power levels, could be provided in a much shorter time frame than noted in the NGIPS master plan. This paper will explore the combinations of prime movers and advanced generators that would suit the three power generation modules of the HFAC system. A description of the prime mover and the generator used for each module will be provided to demonstrate the modest level of development needed. The performance parameters for each generation module will be provided, along with key characteristics and dimensions for the set. In the end, the paper will make the case that demonstration of a HFAC power generation system can be made in the short term, allowing the shipbuilding community to take advantage of the benefits of state‐of‐the‐art power dense electrical generation.
Warfighter Inclusion in System Development: The Operational Perspective in Defining Design Requirements
Authors: WALLACE DANIEL , WHITE DENNIS , DAVIDSON KAROLE
Published: April 2009

Human systems integration (HSI) is integral to any comprehensive system engineering process. HSI is defined by the International Conference on System Engineering as “interdisciplinary technical and management processes for integrating human considerations within and across all system elements; an essential enabler to systems engineering practice.” But how does one accomplish this interdisciplinary integration? This paper highlights the essential role of the warfighter as an overarching elicitor and integrator of system requirements, and how to effectively exploit this crucial resource. All complex systems are developed to be used and maintained in a specific operational environment by a trained user. It is therefore imperative that the unique operational perspectives of those users are made part of the design and development process. There are several key opportunities within the acquisition process where qualified, representative users play a significant role in refining the system's requirements and defining how the total system will perform. Active participation from the warfighter and user community in the design process will aid in identifying issues early enough to make a meaningful influence on design, fosters warfighter acceptance of the system, reduces the risks associated with warfighter alterations to system configurations, and validates total system performance using human in the loop evaluations.
Architecting a System of Systems Responding to Maritime Domain Terrorism by Orthogonal Array Experiment
Authors: HUYNH THOMAS , CONNETT BRIAN , CHIU‐ROURMAN JARED “CHEWEY” , DAVIS JENNIFER , KESSLER ANDREW , ORAVEC JOSEPH , SCHEWFELT MICHAEL , WARK SHAUNNAH
Published: April 2009

In this work we solve the problem of architecting a conceptual, cost‐effective, near‐term system of systems (SoS) to respond to terrorist threats to the United States emanating from the maritime domain. The threats include a weapon of mass destruction smuggled on a container ship, a commandeered ship used as a weapon, and small boats used by terrorists to attack maritime commerce traffic and critical shore infrastructures. We formulate the problem as an assignment problem, which is then solved using the orthogonal array experiment. The optimality of the resulting SoS architecture is validated against a heuristically developed architecture and an optimal effective, but not necessarily cost‐effective, architecture obtained also with the orthogonal array experiment approach. The principal results of the orthogonal array experiment method reported herein underline this successful exploratory work in architecting an SoS. This method can be extended to architecting of other systems of systems.
Clermont‐Ferrand dental school’ curriculum: an appraisal by last‐year students and graduates
Authors: Nicolas E. , Baptiste M. , Roger‐Leroi V.
Published: April 2009

Objective:  Last‐year students and young graduates of the Clermont‐Ferrand dental school (France) assessed their professional skills in order to shed light on those which are perfectly mastered and those which are not, with the aim of improving the undergraduate training given by the school.

Methods:  A questionnaire was handed out to students in their last two years and to young graduates (n = 170). They were asked to appraise their self‐assessed level concerning 52 skills using a 0–10 visual analogue scale. The respondents also had to highlight the five skills which, according to them, needed to be improved during the programme.

Results:  Thirteen skills obtained a score lower than 5/10 showing a need of more thorough training, notably in the fields of implantology, paradontal surgery, temporomandibular joint disorders and dental practice financial management. Among these, five skills were found that demand in depth acquisition according to respondents. However, these five skills are not necessarily the ones which obtained the lowest scores.

Conclusions:  Our school needs to improve the quality of its training, notably by reorganising some of its courses and by intensifying student’ training in outreach programmes, particularly in private practice, where skills like the financial management of a dental practice could be more easily acquired than in a hospital environment.
Melatonin reduces induction of Bax, caspase and cell death in methamphetamine‐treated human neuroblastoma SH‐SY5Y cultured cells
Authors: Wisessmith Wilaiwan , Phansuwan‐Pujito Pansiri , Govitrapong Piyarat , Chetsawang Banthit
Published: April 2009

Abstract:  Several studies demonstrated that methamphetamine (MA)‐treated human neuroblastoma cells exhibit increased oxidative stress, which regulates intracellular signaling cascades leading to cell death. Melatonin has a potential as a direct free radical scavenger and protects against cell death caused by MA. The objective of this study was to investigate the neuroprotective properties of melatonin on MA‐induced induction of death signaling cascade and neuronal cell degeneration in human neuroblastoma SH‐SY5Y cultured cells. The results of the present study demonstrate that MA significantly reduced cell viability in SH‐SY5Y cultured cells. Desipramine, a monoamine uptake blocker, and melatonin reversed the toxic effect of MA in reducing cell viability. Induction of Bax, Bcl‐2 and cleaved caspase‐3 protein levels were observed in SH‐SY5Y cultured cells treated with MA, whereas the induction of Bax and cleaved caspase‐3 was diminished by melatonin. Visualization of the induction of Bax using immunofluorescence but a reduction in mitochondrial sites using red‐fluorescent mitochondria‐staining dye was more obviously apparent in MA‐treated cells than in untreated control cells and, again, this effect was abolished by melatonin. These findings demonstrate important roles of Bax and caspase in death signaling cascade, and the protective effects of melatonin in MA‐treated SH‐SY5Y cells.
Neuralgia‐inducing cavitational osteonecrosis: a status report
Authors: Sciubba JJ
Published: April 2009

Neuralgia‐inducing cavitational osteonecrosis remains controversial several years following the initial description. Changing etiologic concepts have led to confusion as well as the significant departures from the concept first defined by Ratner which served as the basis for the explaining the pain syndrome with features of trigeminal neuralgia. Since the earliest publications on the subject by Bouquot and colleagues there have been many challenges and counterclaims to the concept introduced, with a discussion of these included. Finally, absence of any form of research design and approval by institutional review panels remains a weakness in terms of acceptance of the information provided in the literature said to support the stated etiology of this entity.
An animal model of intrinsic dental erosion caused by gastro‐oesophageal reflux disease
Authors: Higo T , Mukaisho K , Ling Z‐Q , Oue K , Chen K‐H , Araki Y , Sugihara H , Yamamoto G , Hattori T
Published: April 2009

Objectives:  To explore the association between dental erosion and gastro‐oesophageal reflux disease (GORD), we used an animal model of GORD.

Materials and Methods:  We performed an operation to force gastro‐duodenal contents reflux in male Wistar rats, and examined the teeth in the reflux rats at 15 or 30 weeks postoperatively. Dental erosion was evaluated based on a slightly modified index from a previous report. Estimation of pH was employed in the oesophageal and gastric contents.

Results:  Macroscopically, dental erosion was only detected in the reflux rats. Histopathologically, dentin exposure was detected in three of the seven cases after 30 weeks. Alveolar bone destruction and osteomyelitis were also noted in severe cases. The pH of the oesophageal and stomach contents was 6.93 ± 0.15 and 3.7 ± 0.39, respectively.

Conclusions:  We confirmed the relationship between dental erosion and GORD. First step of dental erosion caused by GORD is the loss of surface enamel induced by regurgitation of an acidic liquid and acidic gas. Subsequently, further destruction of dental hard tissues and tooth supporting structure is accelerated by mixed juice with gastric and duodenal contents. The reflux animal model is a useful tool to examine the mechanism of dental erosion in GORD.
A study to evaluate the relationship between periodontitis, cardiovascular disease and serum lipid levels
Authors: Sridhar R , Byakod G , Pudakalkatti P , Patil R
Published: April 2009

Abstract:  Background:  The search for cellular mechanisms linking periodontitis to changes in systemic health has resulted in the evolution of a new area of lipid research. So far the causality and possible pathways of the association between periodontal disease and cardiovascular disease is obscure.

Method:  A total of 120 subjects were included in the study with 30 subjects in each of the following groups: healthy group (A), chronic periodontitis group (B), coronary heart disease (CHD + periodontitis group) (C) and CHD − periodontitis group (D). All subjects underwent oral examination and their Gingival Index, Oral Hygiene Index, Periodontal Disease Index scores and attachment loss were recorded. Two millilitres of fasting venous blood sample was drawn and tested for the level of total cholesterol, low density lipoprotein (LDL), high density lipoprotein (HDL) and triglyceride level.

Results and Conclusion:  The results revealed no significant difference with respect to the lipid profile levels between the four groups. Interpreting the results of the study, periodontal disease did not cause an increase in total CHL, LDL or triglyceride levels or a decrease in the HDL levels in an otherwise systemically healthy individual or in a CHD patient. Periodontitis in a CHD patient did not seem to exacerbate the destruction of periodontal tissue. Higher triglyceride levels did not have any correlation with the severity of attachment loss in a periodontitis subject.
Large‐scale changes in abundance of terricolous bryophytes and macrolichens in Finland
Authors: Mäkipää Raisa , Heikkinen Juha
Published: April 2009

Abstract. Major changes in forest floor vegetation were identified on the basis of three nationwide surveys conducted as part of national forest inventories in 1951–1953, 1985–1986 and 1995. These surveys provided objectively selected, statistically representative samples of all forested land in Finland. The 1951–1953 data consist of over 10000 sample plots, while the later surveys were conducted on ca. 3000 permanent plots.

Changes in relative abundance of dominant species (i.e. in the proportions of species of the total cover of forest floor vegetation) were analysed across biogeographical provinces. Spatial correlation, systematic sampling, partial re‐measurement and multiple testing were taken into account in assessment of the statistical significance of the observed changes.

The most notable changes in forest floor vegetation were a decrease in the relative abundance of Hylocomium splendens and an increase in Dicranum polysetum. In N Finland, where forests are grazed by semi‐domestic reindeer, we observed a decline in the abundance of Cladina lichens and an increase in Dicranum mosses. Peltigera aphthosa declined throughout the country. Polytrichum juniperinum, Pohlia nutans, and Brachythecium species, which occupy disturbed sites or grow on litter, increased in abundance. The relative abundance of Sphagnum species decreased, particularly in W Finland, where Pleurozium schreberi was favoured. A major decline in S. fuscum was also recorded in C and E Finland.

Many of the changes detected in this study are apparently related to intensified forest management; but solely on the basis of this study, its effects cannot be distinguished from those of other large‐scale environmental changes.
Can soil temperature direct the composition of high arctic plant communities?
Authors: Brooker Rob , van der Wal René
Published: April 2009

Abstract. Low temperatures exert a primary constraint on the growth of high arctic vascular plants. However, investigations into the impact of temperature on high arctic plants rarely separate out the role of air and soil temperatures, and few data exist to indicate whether soil temperatures alone can significantly influence the growth of high arctic vascular plants in a manner that might direct community composition.

We examined the response of high arctic plants of three functional types (grasses, sedges/rushes and non‐graminoids) to manipulated soil temperature under common air temperature conditions. Target plants, within intact soil cores, were placed in water baths at a range of temperatures between 4.9 and 15.3 °C for one growing season. Grasses responded most rapidly to increased soil temperature, with increased total live plant mass, above‐ground live mass and total below‐ground live mass, with non‐graminoids having the lowest, and sedges/rushes an intermediate degree of response. The ratio of above‐ground live mass to total live mass increased in all growth forms. Grasses, in particular, responded to enhanced soil temperatures by increasing shoot size rather than shoot number. In all growth forms the mass of root tissue beneath the moss layer increased significantly and to a similar extent with increasing soil temperature.

These results clearly indicate that different growth forms, although collected from the same plant community, respond differently to changes in soil temperature. As a consequence, factors influencing soil temperature in high arctic ecosystems, such as global climate change or herbivory (which leads to reduced moss depth and increased soil temperatures), may also direct changes in vascular plant community composition.
Effects of Prosopis flexuosa on soil properties and the spatial pattern of understorey species in arid Argentina
Authors: Rossi Bertilde E. , Villagra Pablo E.
Published: April 2009

Abstract. In arid zones dominant woody plants are capable of causing changes in microclimate and soil properties likely to affect species composition, as well as the establishment and spatial distribution of plant species. In North American and European deserts species richness appears to be higher under the canopy of shrubs and trees, in contrast with Chilean deserts where it seems to be lower. Since Prosopis flexuosa (Fabaceae, Mimosoideae) is the most conspicuous tree in the central Monte desert, Argentina, we analysed the effect of this species on the composition and abundance of the shrub and herbaceous layers and on soil properties. We considered two mesohabitats: ‘under P. flexuosa canopy’ and ‘intercanopy areas’. In addition, we analysed the differences between two microhabitats under canopies: ‘northern part of the canopy’ and ‘southern part of the canopy’. Results indicate that species composition and soil properties are affected by both mesohabitats and microhabitats. We found a higher number of shrubs under canopies, whereas that of grasses and perennial forbs increased in intercanopy areas. Concentrations of organic matter, nitrogen, potassium and phosphorus, factors limiting biological productivity in Monte desert soils, were significantly higher under than outside P. flexuosa canopies. Electrical conductivity and concentrations of Na+, Ca++, Mg++ were higher in the northern than in the southern microhabitats. No differences in species richness, evenness or diversity were found between mesohabitats or between microhabitats. We conclude that P. flexuosa modifies the spatial pattern of plant species in the shrub and herbaceous layers and the chemical conditions of the soil, generating spatial heterogeneity on different scales.
Germination ecology of the clonal herb Knautia arvensis: Regeneration strategy and geographic variation
Authors: Vandvik Vigdis , Vange Vibekke
Published: April 2009

Abstract. We investigated germination responses and seed recruitment in the clonal grassland herb Knautia arvensis (Dipsacaceae) throughout its distributional range in Norway. Four predicted relationships between germination responses and field regeneration behaviour were tested using phytotron experiments and experimental and observational field studies. Seedlings appeared in all experimental microsites in the field, corroborating phytotron predictions that gap‐ or depth‐sensing strategies should be absent in the species. Seasonal timing patterns were predicted from a cold stratification response in the phytotron, but these were not supported in the field. The relationship between dormancy, germinability during storage, and seed carry‐over in the field largely conformed to expectations. Seeds from four different geographical regions responded differently to temperature and cold stratification and storage. Dormancy and seed carry‐over was higher in seeds from a coastal population, where winters are relatively mild and the probability of repeated freeze‐thaw events is high, than in populations from mountain and inland areas, where winters are colder. This is discussed against two alternative hypotheses about the relationship between climate and dormancy in seasonal climates.
Apparently we do need phytosociological classes to calibrate Ellenberg indicator values!
Authors: Wamelink G.W.W. , van Dobben H.F. , Berendse F.
Published: April 2009

Abstract. We stated (Wamelink et al. 2002) that mean Ellenberg indicator values are biased towards expectations of phytosociologists. Witte & von Asmuth (2003; this volume) have two major points of criticism: (1) the data we used would be systematically biased; (2) in calibrating Ellenberg indicator values for moisture availability against mean spring groundwater level we should have assumed a sigmoid response instead of a linear one. As to (1), a bias in the data would require that wet vegetation types were visited in wet years and dry vegetation types in dry years. We do not see any evidence for this. As to (2), our data do not provide strong evidence for a sigmoid relation instead of a linear one. Neither is there any indication that the bias in the Ellenberg indicator values would disappear when a sigmoid function would be fitted. We do agree with Witte & von Asmuth that it is preferable to characterize the species’ response by those variables to which they most directly respond.
BOOK REVIEWS
Authors: Michaletz Sean T. , Johnson Edward A.
Published: April 2009

Book reviewed in this article:

Trabaud, L. & Prodon, R. (eds.) 2002. Fire and Biological Processes. x + 345 pp. Backhuys Publishers, Leiden, The Netherlands. ISBN 90‐5782‐116‐8 (paperbound). Price: EUR 90.‐.
Subalpine forest development following a blowdown in the Mount Zirkel Wilderness, Colorado
Authors: Kulakowski Dominik , Veblen Thomas T.
Published: April 2009

Abstract. We documented the occurrence of a 1934 blowdown in a subalpine forest in northwestern Colorado, USA. Prior to the blowdown, the stand was dominated by old‐growth Picea engelmannii ‐ Abies lasiocarpa forests. Although blowdowns are believed to trigger outbreaks of Dendroctonus rufipennis (spruce beetle), we found no detectable increase in beetle caused mortality. Forest recovery was by both release of the previously suppressed regeneration and by new seedling establishment. Both recovery pathways were dominated by Abies. The blowdown thus caused a shift in species dominance from Picea to Abies; 65 yr after the blowdown, the fallen logs and tip up mounds continue to provide favourable habitat for seedling establishment of both species. The present study shows that the legacy of blowdowns can influence forest dynamics for decades following the disturbance event.
Succession in sub‐boreal forests of West‐Central British Columbia
Authors: Clark Donald F. , Antos Joseph A. , Bradfield Gary E.
Published: April 2009

Abstract. Structural and compositional changes were analysed over the course of 400+ yr of post‐fire succession in the sub‐boreal forests of west‐central British Columbia. Using a chronosequence of 57 stands ranging from 11 to 438 yr in age, we examined changes in forest structure and composition with complementary PCA and DCA ordination techniques. To determine stand ages and timing of tree recruitment, approximately 1800 trees were aged. Most early successional forests were dominated by Pinus contorta, which established rapidly following fire. Abies lasiocarpa and Picea glauca × engel‐mannii were also able to establish quickly, but continued to establish throughout the sere. Few Pinus contorta survived beyond 200 yr, resulting in major changes in forest structure. In some stands P. contorta never established, which led to considerable variation among stands less than 200 yr old. The oldest forests converged on dominance by Abies lasiocarpa. Vascular plant diversity decreased during succession whereas canopy structure became more complex as gap dynamics developed. Although these sub‐boreal forests contain few tree species, successional changes were pronounced, with structure changing more than composition across the chronosequence.
Soil fertility and herb facilitation mediated by Retama sphaerocarpa
Authors: Rodríguez‐Echeverría S. , Pérez‐Fernández M.A.
Published: April 2009

Abstract. Woody legumes growing in dry climates can increase soil nutrient content and facilitate plant growth in their understorey. We investigated differences in soil fertility and herbaceous community in relation to the presence and absence of the legume Retama sphaerocarpa in a shrubland in a mediterranean type climate. The results showed a higher content of limiting nutrients for plant growth, such as phosphorus and nitrogen, under the R. sphaerocarpa canopy. Herbaceous biomass, cover and nitrogen content increased below the canopy. However, species richness and diversity were diminished in the presence of a dense canopy of R. sphaerocarpa. Nitrogen isotopic analysis did not indicate a clear relationship between symbiotic fixation in R. sphaerocarpa and nitrogen content of soil and plants under its canopy. Nevertheless, herbs growing in the understorey showed a linear correlation between foliar N content and 15N values. The existence of a dense shrub canopy induced a smaller monthly variation in herb richness, diversity and biomass, suggesting that it provides a stable microhabitat facilitating herbaceous vegetation establishment and growth. The ‘shelter’ effect was more important when environmental conditions became stressful for herbaceous plants.