bluuebunny/crossref_metadata_2025 huggingface dataset:
Activation of Phospholipase A2 Is Associated with Generation of Placental Lipid Signals and Fetal Obesity
Authors: Varastehpour Ali , Radaelli Tatjana , Minium Judi , Ortega Henar , Herrera Emilio , Catalano Patrick , Hauguel-de Mouzon Sylvie
Published: January 2006

Context: Obesity and diabetes during pregnancy are associated with increased insulin resistance and higher neonatal adiposity. In turn, insulin resistance triggers inflammatory pathways with accumulation of placental cytokines.

Objective: To determine placental signals that translate into development of excess adipose tissue, we investigated the role of phospholipases A2 (PLA2) as targets of inflammatory mediators.

Setting: The study was conducted at Case Western Reserve University, Department of Reproductive Biology.

Subjects: Volunteers gave informed written consent in accordance with the Institutional Review Board guidelines. Placenta and cord blood samples were obtained at the time of elective cesarean section in 15 term pregnancies.

Intervention: Neonatal anthropometric measurements were performed within 48 h of delivery. Placentas were grouped based on neonatal percentage body fat as obese (body fat ≥ 16%) and lean control (body fat ≤ 8%).

Main Outcome Measures: The primary outcomes were placenta PLA2 expression and fatty acid concentration.

Results: Expression of PLA2G2A and PLA2G5, the main placenta phospholipases, was greater (P < 0.05) in placenta of obese compared with control neonates and was associated with increased 20:3 and 20:5 omega-3 polyunsaturated fatty acids. TNF-α and leptin content was increased 3-fold in placenta of obese neonates. TNF-α and leptin both induced a time-dependent activation of PLA2G2 and PLA2G5 in placental cells.

Conclusion: Accumulation of omega-3 fatty acids through secretory PLA2 activation is associated with high neonatal adiposity. We propose that the generation of placental lipid mediators through TNF-α and leptin stimulation represents a key mechanism to favor excess fetal fat accretion.
Effects of High-Dose Growth Hormone on Glucose and Glycerol Metabolism at Rest and during Exercise in Endurance-Trained Athletes
Authors: Healy M. L. , Gibney J. , Pentecost C. , Croos P. , Russell-Jones D. L. , Sönksen P. H. , Umpleby A. M.
Published: January 2006

Context: Recombinant human-GH (r-hGH), in supraphysiological doses, is self-administered by athletes in the belief that it is performance enhancing.

Objective: The objective of this study was to determine whether r-hGH alters whole-body glucose and glycerol metabolism in endurance-trained athletes at rest and during and after exercise.

Design: This was a 4-wk double-blind placebo-controlled trial.

Setting: This study was conducted at St. Thomas Hospital (London, UK).

Participants: Twelve endurance-trained male athletes were recruited and randomized to r-hGH (0.2 U/kg·d) (n = 6) or identical placebo (n = 6) for 4 wk. One (placebo group) withdrew after randomization.

Intervention: Intervention was conducted by randomization to r-hGH (0.2 U/kg·d) or identical placebo for 4 wk.

Main Outcome Measures: Whole-body rates of appearance (Ra) of glucose and glycerol (an index of lipolysis) and rate of disappearance of glucose were measured using infusions of d-[6–6-2H2]glucose and 2H5-glycerol.

Results: Plasma levels of glycerol and free fatty acids and glycerol Ra at rest and during and after exercise increased during r-hGH treatment (P < 0.05 vs. placebo). Glucose Ra and glucose rate of disappearance were greater after exercise during r-hGH treatment (P < 0.05 vs. placebo). Resting energy expenditure and fat oxidation were greater under resting conditions during r-hGH treatment (P < 0.05 vs. placebo).

Conclusions: r-hGH in endurance-trained athletes increased lipolysis and fatty acid availability at rest and during and after exercise. r-hGH increased glucose production and uptake rates after exercise. The relevance of these effects for athletic performance is not known.
Activity of Irinotecan and the Tyrosine Kinase Inhibitor CEP-751 in Medullary Thyroid Cancer
Authors: Strock Christopher J. , Park Jong-In , Rosen D. Marc , Ruggeri Bruce , Denmeade Samuel R. , Ball Douglas W. , Nelkin Barry D.
Published: January 2006

Context: Medullary thyroid cancer (MTC) is a cancer of the parafollicular C cells that commonly presents with an inherited or acquired RET gene mutation. There is currently no effective systemic treatment for MTC.

Objective: The objective of this study was to investigate a systemic therapeutic approach to treat MTC. We studied the sensitivity of an MTC cell line and xenograft to irinotecan, alone and in combination with the tyrosine kinase inhibitor, CEP-751.

Results: In TT cell culture and xenografts, irinotecan treatment was highly effective. This effect was augmented by treatment with CEP-751. Treatment of TT cell xenografts resulted in durable complete remission in 100% of the mice, with median time to recurrence of 70 d for irinotecan alone and more than 130 d for irinotecan plus CEP-751. Although irinotecan induced an S phase checkpoint arrest in TT cells, CEP-751 in combination with irinotecan resulted in a loss of this arrest. CEP-751 induced a loss in the induction of the DNA repair program marked by phospho-H2AX and the checkpoint pathway marked by the activated Chk1 pathway.

Conclusions: Irinotecan treatment was highly effective in a preclinical model of human MTC, resulting in complete remission in 100% of the xenografts treated. The duration of remission was further enhanced by combination with the kinase inhibitor, CEP-751. These results suggest that irinotecan, alone or in combination, may be useful for the treatment of MTC.
Practical One-step Synthesis of Symmetrical Liquid Crystalline Dialkyloligothiophenes for Molecular Electronic Applications
Authors: Leroy Julie , Levin Jeremy , Sergeyev Sergey , Geerts Yves
Published: January 2006

This communication describes extremely simple one-step synthesis of α,α′-dialkyloligothiophenes by the lithiation/alkylation of the corresponding commercially available oligothiophenes. Use of t-BuOK to enhance the reactivity of lithiated oligothiophene species towards alkyl halides is crucially important.
Asymmetric Addition of Alkynylzinc Reagents to Nitrones Utilizing Tartaric Acid Ester as a Chiral Auxiliary
Authors: Wei Weilin , Kobayashi Masato , Ukaji Yutaka , Inomata Katsuhiko
Published: January 2006

The asymmetric addition of alkynylzinc reagents, prepared in situ from dialkylzinc and 1-alkynes, to nitrones was achieved by utilizing di(t-butyl) (R,R)-tartrate as a chiral auxiliary to afford the corresponding optically active (R)-α-substituted propargylic N-hydroxylamines. By the addition of product-like N-hydroxylamine, unprecedented enhancement of enantioselectivity was observed to afford the N-hydroxylamines up to 95% ee.
Revenue Recognition: Judgment in the Spotlight / LA CONSTATATION DES PRODUITS: PLEINS FEUX SUR LE JUGEMENT
Authors: CONROD JOAN , CUMBY JUDY
Published: January 2006

This paper examines recent history in the area of revenue recognition in financial reporting by Canadian public companies. Revenue recognition is critical because of the profound impact this accounting policy has on the financial statements, but it can be highly judgmental. Restatement of public financial statements is taken as evidence that the reliability of the reported results, as initially presented, is questionable ‐ that is, the financial statements do not fairly reflect the financial position of the organization. We examine recent newsworthy examples of restatement of revenue by Canadian public companies to determine whether this can be traced to faulty professional judgment or to other circumstances, such as deliberate misrepresentation.

Les auteures se penchent sur l'histoire récente de la constatation des produits, dans l'information financière communiquée par les sociétés ouvertes canadiennes. L'importance cruciale de la constatation des produits tient aux répercussions profondes qu'a la méthode de constatation sur les états financiers et au fait qu'elle peut faire largement appel au jugement. Les auteures évaluent certains exemples canadiens récents de retraitement des produits qui sont dignes d'être rendus publics, afin d'en déterminer les paramètres.
From Accounting to “Forecounting”*
Authors: CORMIER DENIS , MAGNAN MICHEL L.
Published: January 2006

Using Ross Skinner's 1995 CA Magazine article, “Judgment in Jeopardy", as a stepping stone, we revisit the meaning of professional judgment in accounting in light of developments in standard setting, financial markets, and business operations that have taken place over the past two decades. We argue that it is time to change the view that accountants' professional judgment is the application of accounting‐based knowledge and experience in the selection of an appropriate accounting method. Accountants now face a standard‐setting context that emphasizes the estimation of future cash flows as well as new business and financial realities. This context implies that, in exercising their professional judgment to choose between forecast alternatives, accountants must rely on knowledge and experience from other disciplines (even though this is not well integrated into accounting). Hence, accounting must evolve from its traditional stewardship role to the new role of “forecount‐ing” (the estimation of future cash flows). The implications as well as the challenges of that evolution are discussed.
Quantification and Persuasion in Managerial Judgement*
Authors: KADOUS KATHRYN , KOONCE LISA , TOWRY KRISTY L.
Published: January 2006

Accounting involves assigning numbers to events — quantifying them. Conventional wisdom holds that putting numbers to an argument enhances its persuasive power. There is, however, little scholarly evidence to support or refute this claim, in accounting or elsewhere. In this paper, we develop an original process‐based model of how quantification influences persuasion. We posit that including a high‐quality quantified analysis in a proposal enhances its persuasive power by increasing both the perceived competence of the proposal preparer and the perceived plausibility that a favorable outcome could occur. Under some conditions, however, quantification also encourages criticism of the details of the proposal, which potentially offsets these effects. We experimentally test implications of our model in a managerial decision setting, investigating conditions in which quantification is more and less likely to result in criticism of the quantified proposal and, thus, less and more likely to be persuasive. We also test the model itself using structural equations methods. Results largely support the model, which should prove of value to researchers interested in the effects of quantification on judgements and to those interested in persuasion.
Determinants of the Time Series of Earnings and Implications for Earnings Quality*
Authors: ANCTIL REGINA M. , CHAMBERLAIN SANDRA
Published: January 2006

This paper examines whether differences in accrual accounting methods across balance sheet accounts influence the time‐series process of earnings. We define earnings quality as the responsiveness of earnings to shifts in permanent earnings and predict that responsiveness will increase in a firm's use of variable rate debt, where accruals move directly with shifts in interest rates. We also predict that responsiveness will decrease in a firm's investment in property plant and equipment because depreciation is largely predetermined and does not respond to shifts in opportunity costs. To test these hypotheses, we regress earnings on lagged earnings and a proxy for permanent earnings (that is, the implied dividend annuity in lagged equity value). Within the context of an adjustment cost model, this regression captures the responsiveness of earnings by the coefficient on lagged price and by one minus the coefficient on lagged earnings. Consistent with this framework, we find the unconstrained estimated coefficients on these two variables to be negatively correlated. Furthermore, consistent with our hypotheses, we find that the coefficient on lagged earnings (lagged price) is positively (negatively) associated with the relative magnitude and life of fixed assets on the balance sheet and negatively (positively) associated with the relative magnitude of variable rate debt on the balance sheet.
Earnings Quality under Rules‐ versus Principles‐based Accounting Standards: A Test of the Skinner Hypothesis / LA QUALITÉ DES RÉSULTATS SELON QUE LES NORMES COMPTABLES SONT AXÉES SUR LES RÈGLES OU SUR LES PRINCIPES: VÉRIFICATION DE L'HYPOTHÈSE DE SKINNER*
Authors: WEBSTER ERIN , THORNTON DANIEL B.
Published: January 2006

We provide preliminary evidence, consistent with Skinner (1995), that Canada's relatively principles‐based GAAP yield higher accrual quality than the United States' relatively rules‐based GAAP. These results stem from a comparison of the Dechow‐Dichev (2002) measure of accrual quality for cross‐listed Canadian firms reporting under both Canadian and U.S. GAAP. However, we document lower accrual quality for Canadian firms reporting under U.S. GAAP than for U.S. firms, which are subject to stronger U.S. oversight, reporting under U.S. GAAP. The latter results suggest that stronger U.S. oversight compensates for inferior accrual quality associated with rules‐based GAAP. Consistent with the positive effect of Canada's principles‐based GAAP and the offsetting negative effect of Canada's weaker oversight, we find no overall difference in accrual quality between Canadian firms reporting under Canadian GAAP and U.S. firms reporting under U.S. GAAP. Our results imply that (1) policymakers who wish to compare the effectiveness of oversight across jurisdictions must control for the GAAP effect; and (2) accounting standard‐setters who wish to compare the effectiveness of principles‐ versus rules‐based GAAP must control for oversight strength.
R&D Reporting Biases and Their Consequences*
Authors: Lev Baruch , Sarath Bharat , Sougiannis Theodore
Published: January 2006

The immediate expensing of research and development (R&D) expenditures is often justified by the conservatism principle. However, no accounting procedure consistently applied can be conservative throughout the firm's life. We therefore ask the following questions: (1) When is the expensing of R&D conservative and when is it aggressive, relative to R&D capitaliza‐tion? (2) What are the capital‐market implications of these reporting biases? To address these questions we construct a model of profitability biases (differences between reported profitability under R&D expensing and capitalization) and show that the key drivers of the reporting biases are the differences between R&D growth and earnings growth (momentum), and between R&D growth and return on equity (ROE). Companies with a high R&D growth rate relative to their profitability (typically early life‐cycle companies) report conservatively, while firms with a low R&D growth rate (mature companies) tend to report aggressively under current generally accepted accounting principles. Our empirical analysis, covering the period 1972‐2003, generally supports the analytical predictions.

In the valuation analysis we find evidence consistent with investor fixation on the reported profitability measures: we detect undervaluation of conservatively reporting firms and overvaluation of aggressively reporting firms. These misvaluations appear to be corrected when the reporting biases reverse from conservative to aggressive and vice versa. This evidence is consistent with behavioral finance arguments about investor cognitive biases.
CEO Compensation and Stakeholders' Claims*
Authors: ARORA ALKA , ALAM PERVAIZ
Published: January 2006

The traditional view that a corporation exists solely to serve the interests of the firm's shareholders has given way to a changing view that recognizes the importance of corporate constituents in addition to shareholders. Prior studies demonstrate a significant association between the sensitivity of CEO compensation and a firm's stock prices. However, the association between CEO compensation and the claim of other primary stakeholders (customers, employees, suppliers) has not been examined. The purpose of this study is to investigate whether the adoption of long‐term incentive plans aligns the interest of the CEO with the interest of the primary stakeholders in the firm. Using the fixed‐effect regression, our results indicate a significant association between the change in CEO compensation and the claims of the customers, shareholders, and employees. We contribute to the literature by demonstrating that the managers are accountable not only to the shareholders but also to primary stakeholders.
Shareholder Income Taxes and the Relation between Earnings and Returns*
Authors: DHALIWAL DAN S. , ERICKSON MERLE M. , LI OLIVER ZHEN
Published: January 2006

The purpose of this study is to investigate whether and how shareholder‐level taxes affect earnings response coefficients (ERCs). Our tests indicate that when the tax rate on dividends increases, ERCs decrease for firms with high levels of dividend yield and whose marginal investor is likely to be an individual. For firms with high levels of share repurchase yield and whose marginal investor is likely to be an individual, an increase in dividend tax rate has no discernible effect on ERCs. These results are consistent with the notion that the tax penalty on dividends, relative to capital gains, reduces the earnings‐return relation.
Accounting Standards: Rules, Principles, or Wild Guesses?/ LES NORMES COMPTABLES: RÉGLES, PRINCIPES OU JEU DE HASARD?
Authors: BEECHY THOMAS H.
Published: January 2006

This commentary considers the issue of judgment in the application of accounting standards. The rules‐versus‐principles argument is discussed, with particular attention to the relationship between accounting standards, accounting objectives, and the exercise of judgment. Both the types of judgment and the locus of judgment are examined: What types of accounting estimates are needed, and who makes those estimates? In particular, the problematic use of probability estimates and expected values is discussed. The paper concludes with proposals for improving the quality of accounting standards.
Earnings Management to Minimize Superfund Clean‐up and Transaction Costs*
Authors: JOHNSTON DEREK , ROCK STEVE
Published: January 2006

We investigate whether firms identified as potentially responsible parties (PRPs) under the Comprehensive Environmental Response, Compensation, and Liability Act (more commonly known as Superfund) appear to manipulate earnings to minimize their exposure to Superfund clean‐up and transaction costs. We analyze the discretionary accrual behavior of 612 PRPs from 1981 to 1995 and increase the power of our tests by identifying those PRPs with the most incentive to manage earnings during PRP identification years. The results provide robust evidence consistent with the hypothesis that these PRPs use income‐reducing discretionary accruals during PRP identification years in an attempt to minimize Superfund clean‐up and transaction costs. We also consider whether PRPs' incentives to manage earnings change in response to a change in the EPA regulatory regime and find modest evidence consistent with our conjecture.
Disclosure Policy and Market Liquidity: Impact of Depth Quotes and Order Sizes*
Authors: Heflin Frank L. , Shaw Kenneth W. , Wild John J.
Published: January 2006

This paper investigates the relation between disclosure policy and market liquidity. Our tests examine two key aspects of market liquidity, the effective bid‐ask spread and quoted depth, and how they relate to financial analysts' ratings of firms' disclosure policies. We introduce a method of combining order sizes and depth quotes to yield more precise estimates of effective spreads on trades likely constrained by quoted depth. We find that while firms with higher rated disclosures are charged lower effective spreads, they are also quoted lower depth, consistent with the notion that better disclosures reduce information asymmetry but also cause some liquidity suppliers to exit the market. Therefore, a simple examination of spreads and depths yields ambiguous inferences on the relation between disclosure policy and market liquidity. We resolve this ambiguity by estimating depth‐adjusted effective spreads, and find that firms with higher rated disclosures have lower depth‐adjusted effective spreads across all trade sizes. Consequently, our results reveal a robust inverse relation between disclosure ratings and effective trading costs. This implies that a policy of enhanced financial disclosure is related to improved market liquidity.
Production Externalities, Congruity of Aggregate Signals, and Optimal Task Assignments*
Authors: HUGHES JOHN S. , ZHANG LI , XIE JAI‐ZHENG JAMES
Published: January 2006

In this paper, we consider the role of production externalities in the task assignment problem. Milgrom and Roberts (1992) suggest that complementarities available when agents are assigned to diverse tasks are necessary to overcome distortions in effort allocations caused by an inability to fine‐tune incentives when agents' compensation is based on aggregate imperfect signals. Our analysis formalizes this intuition in a setting that encompasses externalities under both diverse and similar task assignments.
Avoiding Accounting Fixation: Determinants of Cognitive Adaptation to Differences in Accounting Method*
Authors: DEARMAN DAVID T. , SHIELDS MICHAEL D.
Published: January 2006

Much research over the last 30 years has provided evidence that individuals display accounting fixation; that is, their cognitive process does not appropriately adapt to cross‐sectional or temporal differences in an accounting method. This paper presents the results of a quasi‐experimental test of the hypothesis that cognitive adaptation to a change in accounting method is an ordinal interactive function of three person characteristics: relevant accounting knowledge, general problem‐solving ability, and intrinsic motivation to appropriately engage in the decision task. Based on a product‐pricing decision task in which participants are provided with product costs reported by two generally employed product‐costing methods (activity‐based costing [ABC] and volume‐based costing), the results show that the majority of participants did not change their cognitive behavior when there was a change in the costing method. Further, those participants who did adapt to the change in accounting method, and thus avoided accounting fixation, did so by debiasing costs reported by volume‐based costing but not by ABC. Finally, these adapters generally exhibited high values for all three of the person characteristics compared with those who did not adapt.
Taxpayers' Prepayment Positions and Tax Return Preparation Fees*
Authors: JACKSON SCOTT B. , SHOEMAKER PAUL A. , BARRICK JOHN A. , BURTON F. GREG
Published: January 2006

Individuals who have their tax returns professionally prepared often overpay estimated income taxes, effectively giving the government an interest‐free loan. To understand why tax professionals may place their clients in positive prepayment positions, we draw on mental accounting theory. Mental accounting theory suggests that by placing taxpayers in positive prepayment positions, tax professionals induce a favorable mental representation of tax return preparation fees, perhaps allowing them to collect larger fractions of billable time and costs incurred on taxpayers' behalves. Thus, we hypothesize that tax return preparation fees are higher for taxpayers in positive prepayment positions than for taxpayers in negative prepayment positions. Regression results using tax return data for 68,736 taxpayers provide strong support for this hypothesis. To more fully understand the general nature of the relationship between taxpayers' prepayment positions and tax return preparation fees, we adapt the prospect theory value function to the tax domain and formulate three additional hypotheses. Consistent with theory, regression results indicate that the relation between taxpayers' prepayment positions and tax return preparation fees is (1) positive, (2) stronger for taxpayers who receive refunds that are less than fees than it is for taxpayers who receive refunds that are greater than fees, and (3) stronger for taxpayers in negative prepayment positions than for taxpayers in positive prepayment positions.
Komplementäre Regelungsarchitekturen für haptische Displays (Complementary Control Architectures for Haptic Displays)
Authors: Hoogen Jens , Schmidt Günther
Published: January 2006

Die Stabilität von Systemen zur kinästhetischen Interaktion hängt wesentlich von den im Betrieb variierenden dynamischen Eigenschaften des Bedieners und der virtuellen Umgebung ab. In diesem Artikel werden die Stabilitätseigenschaften von Impedanz-, Admittanz- und Dreikanal-Regelungsarchitekturen mit Hilfe des Parameterraum-Verfahrens in Abhängigkeit von Bediener- und Umgebungssteifigkeit untersucht. Durch Einführen des Konzepts der Dualität im Parameterraum wird gezeigt, dass sich Dreikanal-Architekturen aufgrund ihrer komplementären Stabilitätseigenschaften besser für den Entwurf einer adaptiven strukturvariablen Regelung eignen, als das duale Impedanz-Admittanz-Architekturpaar. Experimentelle Untersuchungen mit einem als haptisches Display betriebenen Industrieroboter belegen die theoretischen Ergebnisse.
Rahmenwerk zur teilautonomen Aufgabenbearbeitung mit Rehabilitationsrobotern (Framework for Semi-autonomous Task Execution with Rehabilitation Robots)
Authors: Martens Christian , Gräser Axel
Published: January 2006

Rehabilitationsroboter mit einem realen Nutzen für ihre Anwender müssen Aufgaben auf hohem Abstraktionsniveau bearbeiten können. Dies macht die situationsbezogene Planung und Ausführung von Handlungen durch das Robotersystem erforderlich. Beim jetzigen Stand der Forschung und Entwicklung ist die Umsetzung dieser Forderung nur durch die Einbeziehung der kognitiven Fähigkeiten des Anwenders in den Prozess der Aufgabenbearbeitung umsetzbar. Im vorliegenden Beitrag wird ein softwaretechnisches und algorithmisches Rahmenwerk vorgestellt, das eine Erweiterung von Rehabilitationsrobotern um die Fähigkeit zur teilautonomen Aufgabenbearbeitung ermöglicht.
Systematischer Entwurf eines signalbasierten Fehlerdiagnosesystems, Teil 1 (A Systematic Designing Approach for Signal-based Fault Diagnosis System, Part 1)
Authors: Feid Michael , Pandit Madhukar
Published: January 2006

Der vorliegende Aufsatz beschäftigt sich mit der Entwurfsmethodik eines signalbasierten Fehlerdiagnosesystems. Diagnosesysteme sind dadurch charakterisiert, dass der Entwicklungsaufwand einen beträchtlichen Anteil an den Gesamtsystemkosten darstellt. Folglich ist es von Interesse, Verfahren und Werkzeuge zu schaffen, die einen schnellen und systematischen Entwurf unterstützen.

Es ist das Ziel, Verfahren aus Gebieten der Signal- und Bildverarbeitung sowie der Entscheidungstheorie für die Belange der Fehlerdiagnose zuzuschneiden und damit einen systematischen Entwicklungsprozess für ein signalbasiertes Diagnosesystem zu erarbeiten und anzugeben.

Die hier beschriebene Methodik dient als Grundlage für ein CAE-Tool für den Entwurf eines signalbasierten Diagnosesystems. Teil 1 der Veröffentlichung befasst sich mit den Grundlagen, Teil 2 beschreibt den Entwurf an einem praktischen Beispiel.
Automorphisms and non-integrability
Authors: Pereira Jorge V. , Sánchez Percy F.
Published: January 2006

On this note we prove that a holomorphic foliation of the projective plane with rich, but finite, automorphism group does not have invariant algebraic curves.
Towards an understanding of the interactions of Trypanosoma cruzi and Trypanosoma rangeli within the reduviid insect host Rhodnius prolixus
Authors: Azambuja Patrícia , Ratcliffe Norman A. , Garcia Eloi S.
Published: January 2006

This review outlines aspects on the developmental stages of Trypanosoma cruzi and Trypanosoma rangeli in the invertebrate host, Rhodnius prolixus. Special attention is given to the interactions of these parasites with gut and hemolymph molecules and the effects of the organization of midgut epithelial cells on the parasite development. The vector insect's permissiveness to T. cruzi, which develops in the vector gut, largely depends on the host nutritional state, the parasite strain and the molecular interactions with trypanolytic compounds, lectins and resident bacteria in the gut. T. rangeli invades the hemocoel and once in the hemolymph, can be recognized and activates the defense system of its insect vector, i.e., the prophenoloxidase system, phagocytosis, hemocyte microaggregation, superoxide and nitric oxide activity and the eicosanoid biosynthesis pathway. Taken together, these findings not only provide a better understanding of the interactions parasite - insect vector, but also offer new insights into basic physiological processes involved in the parasites transmission.
Oogenesis and egg development in triatomines: a biochemical approach
Authors: Atella Georgia C. , Gondim Katia C. , Machado Ednildo A. , Medeiros Marcelo N. , Silva-Neto Mário A.C. , Masuda Hatisaburo
Published: January 2006

In triatomines, as well as in other insects, accumulation of yolk is a process in which an extra-ovarian tissue, the fat body, produces yolk proteins that are packed in the egg. The main protein, synthesized by the fat body, which is accumulated inside the oocyte, is vitellogenin. This process is also known as vitellogenesis. There are growing evidences in triatomines that besides fat body the ovary also produces yolk proteins. The way these yolk proteins enter the oocyte will be discussed. Yolk is a complex material composed of proteins, lipids, carbohydrates and other minor components which are packed inside the oocyte in an organized manner. Fertilization triggers embryogenesis, a process where an embryo will develop. During embryogenesis the yolk will be used for the construction of a new individual, the first instar nymph. The challenge for the next decade is to understand how and where these egg proteins are used up together with their non-protein components, in pace with the genetic program of the embryo, which enables cell differentiation (early phase of embryogenesis) and embryo differentiation (late phase) inside the egg.
Beach ridges, foredunes or transgressive dunefields? Definitions and an examination of the Torres to Tramandaí barrier system, Southern Brazil
Authors: Hesp Patrick A. , Dillenburg Sergio R. , Barboza Eduardo G. , Tomazelli Luiz J. , Ayup-Zouain Ricardo N. , Esteves Luciana S. , Gruber Nelson L.S. , Toldo-Jr. Elirio E. , Tabajara Luiz L.C. de A. , Clerot Luiz C.P.
Published: January 2006

Many prograded barriers and some dunefields in theworld have been termed 'beach ridge' plains, but the actual genesis of the 'ridges' is often unknown. Use of the terms, berms, beach ridges and foredunes is also confusing in the literature because their definitions are highly variable and are commonly used interchangeably. Thus, the formation and definition of sand berms, beach ridges and foredunes is briefly reviewed. Beach ridges are re-defined as entirely wave formed deposits which are most commonly formed during high wave conditions and/or elevated water levels (e.g. storm surges). Foredunes are formed by aeolian sand deposition in vegetation on the backshore. Some dunefields in Brazil have been called beach ridge plains when they are, in fact, foredune plains, transgressive dunefields, or complex barriers (i.e. barriers comprising two types of dunes). The Holocene barrier extending from Torres to Tramandaí in southern Brazil has been regarded as a beach ridge plain. The landforms of this Holocene barrier comprise wide, relatively linear, widely spaced (400-600m), shore parallel ridges on the landward half, and more closely spaced (80-400m), lobate and crescentic, discrete ridges on the seaward half. Low, rolling dunefields, sand sheets, nebkha fields and deflation plains occur between the ridges. The barrier is re-interpreted as a prograded, transgressive dunefield barrier.
History on the biological nitrogen fixation research in graminaceous plants: special emphasis on the Brazilian experience
Authors: Baldani José I. , Baldani Vera L.D.
Published: January 2006

This review covers the history on Biological Nitrogen Fixation (BNF) in Graminaceous plants grown in Brazil, and describes research progress made over the last 40 years, most of whichwas coordinated by Johanna Döbereiner. One notable accomplishment during this period was the discovery of several nitrogen-fixing bacteria such as the rhizospheric (Beijerinckia fluminensis and Azotobacter paspali), associative (Azospirillum lipoferum, A. brasilense, A. amazonense) and the endophytic (Herbaspirillum seropedicae, H. rubrisubalbicans, Gluconacetobacter diazotrophicus, Burkholderia brasilensis and B. tropica). The role of these diazotrophs in association with grasses, mainly with cereal plants, has been studied and a lot of progress has been achieved in the ecological, physiological, biochemical, and genetic aspects. The mechanisms of colonization and infection of the plant tissues are better understood, and the BNF contribution to the soil/plant system has been determined. Inoculation studies with diazotrophs showed that endophytic bacteria have a much higher BNF contribution potential than associative diazotrophs. In addition, it was found that the plant genotype influences the plant/bacteria association. Recent data suggest that more studies should be conducted on the endophytic association to strengthen the BNF potential. The ongoing genome sequencing programs: RIOGENE (Gluconacetobacter diazotrophicus) and GENOPAR (Herbaspirillum seropedicae) reflect the commitment to the BNF study in Brazil and should allow the country to continue in the forefront of research related to the BNF process in Graminaceous plants.
General optimal euclidean Sobolev and Gagliardo-Nirenberg inequalities
Authors: Ceccon Jurandir , Montenegro Marcos
Published: January 2006

We prove general optimal euclidean Sobolev and Gagliardo-Nirenberg inequalities by using mass transportation and convex analysis results. Explicit extremals and the computation of some optimal constants are also provided. In particular we extend the optimal Gagliardo-Nirenberg inequality proved by Del Pino and Dolbeault 2003 and the optimal inequalities proved by Cordero-Erausquin et al. 2004.
Complementary Lagrangians in infinite dimensional symplectic Hilbert spaces
Authors: Piccione Paolo , Tausk Daniel V.
Published: January 2006

We prove that any countable family of Lagrangian subspaces of a symplectic Hilbert space admits a common complementary Lagrangian. The proof of this puzzling result, which is not totally elementary also in the finite dimensional case, is obtained as an application of the spectral theorem for unbounded self-adjoint operators.
On Gymnodactylus amarali Barbour, 1925, with the description of a new species (Sauria, Gekkonidae)
Authors: Vanzolini Paulo Emilio
Published: January 2006

Gymnodactylus amarali Barbour, 1925, was previously considered to be a subspecies of G. geckoides, with a wide distribution in the Brasilian cerrados. Examination of a specimen from Alto Parnaíba, Maranhão, near the type locality (Engenheiro Dodt, Piauí), indicates that it is a proper species, apparently limited to the upper Parnaíba basin. The form previously identified as G. geckoides amarali is described as a new species, G. carvalhoi, type locality Ipueiras, State of Tocantins, thus diagnosed: color pattern plain or, more often, with moderately contrasted ocelli; dorsal tubercles in 13 - 16 poorly organized longitudinal rows (mode 14, 72%); 31 - 49 tubercles in a paramedian row; 17 - 22 transverse rows of ventral scales; 13 - 18 infradigital lamellae on toe IV; tail longest in the genus. The new species is statistically compared to parapatric G. geckoides, widespread in the caatingas. Although only one meristic character (number of tubercle rows) is by itself diagnostic, the species are easily told apart. It is thought on provisional evidence that they are better considered for the time being as full species, not subspecies. A brief consideration is made of the speciation model that seems suitable, to wit, parapatric.
Haematophagous arthropod saliva and host defense system: a tale of tear and blood
Authors: Andrade Bruno B. , Teixeira Clarissa R. , Barral Aldina , Barral-Netto Manoel
Published: January 2006

The saliva from blood-feeding arthropod vectors is enriched with molecules that display diverse functions that mediate a successful blood meal. They function not only as weapons against host's haemostatic, inflammatory and immune responses but also as important tools to pathogen establishment. Parasites, virus and bacteria taking advantage of vectors' armament have adapted to facilitate their entry in the host. Today, many salivary molecules have been identified and characterized as new targets to the development of future vaccines. Here we focus on current information on vector's saliva and the molecules responsible to modify host's hemostasis and immune response, also regarding their role in disease transmission.
A função gonadal do homem obeso
Authors: Lima Nicolau , Cavaliere Humberto , Halpern Alfredo , Medeiros-Neto Geraldo
Published: January 2006

Em homens obesos, os níveis séricos de globulina ligadora de hormônios sexuais (GLHS), bem como de testosterona total, (TT) estão diminuídos. Dados relativos aos níveis séricos de testosterona livre (TL) são controversos. Homens com obesidade mórbida apresentam valores plasmáticos de testosterona livre diminuídos, levando à alteração dos mecanismos de retro-regulação. O decréscimo funcional da amplitude do pulso de LH, bem como a diminuição dos níveis de LH, seriam a causa do hipoandrogenismo. Estudamos dois grupos de homens obesos: Grupo 1 (IMC £ 35kg/m²) e Grupo 2 (IMC > ou = 35kg/m²) antes e após seis meses de dieta hipocalórica (1.200Kcal/dia). Todos os pacientes utilizaram dexfenfluramina (15mg 2x ao dia) durante todo o período do estudo. Níveis plasmáticos de insulina, bem como valores séricos de testosterona total, testosterona livre e LH foram dosados antes e após a perda de peso. Pacientes com obesidade moderada (IMC = 32,3 ± 1,9kg/m²) apresentaram diminuição significativa na concentração sérica de TT (390 ± 120ng/dL), bem como de TL (média ± DP 16,0 ± 4,8pg/mL) quando comparados a normais. A concentração de LH sérico (4,5 ± 2,9mlU/mL) foi considerada normal. Níveis de insulina mostravam-se elevados em todos os pacientes (46,3 ± 30,1miU/mL). Após a perda de peso, notou-se aumento significante (p < 0,01) dos níveis séricos de LH, TT e TL concomitante à queda da concentração de insulina plasmática. Em homens com obesidade de grande porte (IMC = 43,0 ± 6,7kg/m²), os níveis de TT (320 ± 110ng/dL), TL (11,0 ± 2,1pg/mL) e LH (3,1 ±1,3mlU/mL) mostraram-se significativamente menores quando comparados ao Grupo 1 e aos controles normais. Como esperado, após a perda de peso, os níveis séricos de TT, TL e LH aumentaram significativamente enquanto a concentração plasmática de insulina diminuiu. Concluímos que os níveis de TL são dependentes do grau de obesidade: homens com obesidade de grande porte (IMC > ou = 35kg/m²) são considerados como candidatos a apresentarem baixos valores séricos de TL.
Risco cardiovascular em uma população de obesos
Authors: Cercato Cintia , Silva Shirley , Sato Alessandra , Mancini Márcio , Halpern Alfredo
Published: January 2006

Os riscos cardiovasculares associados à obesidade crescem com o índice de massa corporal (IMC). Este estudo teve por objetivos verificar a correlação entre IMC e a prevalência de fatores de risco cardiovascular em uma população de obesos do Hospital das Clínicas da Faculdade de Medicina da USP (HC-FMUSP), e verificar a agregação de fatores de risco em quartis de acordo com o IMC. Foram estudados 474 indivíduos obesos (86,9% do sexo feminino e 13,1% do sexo masculino). Dividimos esta população em quartis de acordo com o IMC e avaliamos a presença de hipertensão arterial, diabetes mellitus e dislipidemia em cada quartil. Estratificamos os pacientes de cada quartil em alto, moderado e baixo risco cardiovascular pelos critérios do National Cholesterol Education Program (NCEP). Fizeram parte do primeiro quartil aqueles com IMC de 30 a 33,99kg/m², e do segundo, terceiro e último quartil, respectivamente aqueles com IMC igual a 34 a 37,19kg/m²,37,2 a 41,77kg/m² e 41,78 a 79,8kg/m². Houve nítido aumento de hipertensão, diabetes e hipertrigliceridemia com o aumento do IMC, o que não foi observado com os níveis de colesterol. A proporção de indivíduos com risco moderado e alto cresceu com o aumento do IMC. Em nossa população de obesos observou-se aumento do risco cardiovascular com o aumento do IMC.
Correlação da medida de espessura intra-abdominal medida pela ultra-sonografia com os fatores de risco cardiovascular
Authors: Leite Claudia C. , Matsuda Daniella , Wajchenberg Bernardo L. , Cerri Giovanni G. , Halpern Alfredo
Published: January 2006

O objetivo do estudo foi determinar se a Gordura intra Abdominal medida pela Ultra-Sonografia (GAUS) em homens e mulheres tem associação com os fatores de risco cardiovascular, comparar essa medida com a circunferência abdominal e diâmetro sagital para precisar qual destes métodos é o melhor preditor de risco cardiovascular (CV), e tentar encontrar um ponto de corte para GAUS que possa definir maior risco de doença CV. Cento e noventa e um homens sadios e 231 mulheres sadias foram submetidas à medidas antropométricas, medidas de pressão arterial sistêmica e dosagens laboratoriais para colesterol, HDL, triglicerídeos e glicemia. A ultra-sonografia intra-abdominal foi realizada para medir espessura visceral. A amostra foi dividida em três grupos de acordo com a presença dos seguintes fatores de risco cardiovascular: 1) grupo de moderado risco - presença de dois ou mais dos fatores: col > 200mg/dL, HDL-colesterol < 45mg/dL, TG > 200mg/dL, Glic > 126mg/dL, PAs > 140mmHg, PAd > 90mmHg; 2) grupo de alto risco com dois ou mais dos fatores: total col > 240mg/dL, HDL-colesterol < 35mg/dL, TG > 200mg/dL +HDL < 35mg/dL, Glic > 126mg/dL, PAs > 140mmHg, PAd > 90mmHg; 3) grupo sem risco: com um ou nenhum dos fatores de risco presentes. Os resultados mostraram que a GAUS tem associação com todos os fatores de risco cardiovascular e tem melhor especificidade e acurácia que a circunferência abdominal e o diâmetro sagital. O valor de 7cm para ambos os sexos foi o ponto de corte para GAUS para predizer risco moderado; 8 e 9cm foram os pontos de cortes obtidos para GAUS para predizer alto risco CV em homens e mulheres, respectivamente. A GAUS é um método útil de determinar espessura visceral e parece ser capaz de predizer risco cardiovascular.
Obesidade, hipertensão arterial e suas influências sobre a massa e função do ventrículo esquerdo
Authors: Ribeiro Filho Fernando S.F. , Rosa Eduardo C. , Faria Alessandra N. , Lerário Daniel D.G. , Ferreira Sandra R.G. , Kohlmann Oswaldo , Zanella Maria-Teresa
Published: January 2006

Para avaliar as influências da obesidade e da hipertensão sobre a massa de ventrículo esquerdo (MVE), estudamos 121 mulheres divididas em 4 grupos: não-obesas normotensas (n = 25), não-obesas hipertensas (n = 30), obesas normotensas (n = 24) e obesas hipertensas (n = 42) quanto a parâmetros antropométricos, ecocardiográficos e de monitorização ambulatorial da pressão arterial (MAPA). As pacientes obesas hipertensas apresentaram maior MVE que os outros grupos - não-obesas normotensas, não-obesas hipertensas e obesas normotensas (167 ± 38,8 vs. 113 + 26,4; vs. 133 ± 26,5; vs. 132 ± 29,2g; p < 0,05, respectivamente) e maior diâmetro de átrio esquerdo (AE) quando comparadas aos grupos de não-obesas, tanto normotensas como hipertensas (36 ± 4,3 vs. 33 ± 5,1; vs. 35 ± 3,9mm; p < 0,05, respectivamente). Obesas normotensas apresentaram MVE similar à do grupo não-obesas hipertensas (133 ± 26,5 vs. 132 ± 29,5g; NS) e aumento de AE quando comparadas às não-obesas normotensas (35 ± 3,9 vs. 31 ± 4,6mm; p < 0,05). Detectou-se correlação entre a circunferência da cintura e a razão cintura-quadril com os níveis pressóricos à MAPA, assim como entre estas medidas e parâmetros ecocardiográficos que avaliam a massa cardíaca; o índice de massa corporal só se correlacionou ao diâmetro do AE. A correção da MVE pela altura ao invés da superfície corpórea aumentou a prevalência de hipertrofia de VE nas obesas (10,6 vs. 36,7%, p < 0,01), mas não nas não-obesas. Ausência de descenso noturno da pressão arterial sistólica à MAPA (non-dipper) foi mais prevalente nas pacientes obesas, hipertensas ou não; entretanto, as obesas hipertensas non-dippers não diferiram das dippers quanto à MVE. Nossos dados demonstram que a obesidade associada à hipertensão aumenta a MVE de modo mais importante do que as condições isoladamente. Concluímos, ainda, que pacientes obesas também apresentam alta freqüência de alterações do ritmo da pressão arterial de 24 horas, caracterizada por menor queda pressórica durante o sono.
Associação entre polimorfismo Gln27Glu do receptor beta2-adrenérgico e hipertensão arterial sistêmica em obesos mórbidos
Authors: Villares Sandra M. , Mancini Marcio C. , Gomez Sérgio , Charf Ana M. , Frazzatto Eliana , Halpern Alfredo
Published: January 2006

Há alguns relatos na literatura sugerindo associação entre polimorfismos do receptor beta2-adrenérgico com obesidade e outros com hipertensão arterial. O objetivo do nosso estudo foi estudar a freqüência de um polimorfismo do receptor beta2 adrenérgico (Gln27Glu) em pacientes obesos (BMI 48 ± 8,2kg/m²) e relacioná-lo com hipertensão arterial, e níveis de triglicérides, colesterol, insulina e glicose no sangue. Encontramos associação deste polimorfismo em obesos com hipertensão arterial.
Eficácia e tolerabilidade das substâncias calorigênicas: ioimbina, triiodotironina, aminofilina combinada a efedrina e fenilpropanolamina no tratamento da obesidade a curto prazo
Authors: Rascovski A. , Millner T.H. , Batalha L. , Reis C. , Mancini M.C. , Halpern A.
Published: January 2006

Objetivo: Determinar a eficácia e tolerabilidade de 4 substâncias calorigênicas: ioimbina, triiodotironina (T3), combinação efedrina-aminofilina e fenilpropanolamina (FPA). Material, Métodos e Desenho da Pesquisa: 103 mulheres obesas (30 < BMI < 40kg/m²), de 18 a 55 anos, foram submetidas a estudo cego comparativo das 4 substâncias associadas a uma dieta com 1.200 calorias (55% HC, 30% gordura e 15% proteínas). As doses utilizadas foram 8mg de ioimbina, 25mcg de T3, 100mg de aminofilina + 25mg de efedrina e 25mg de FPA. Foi ainda incluído um grupo placebo. Os 4 medicamentos e o placebo foram dados 3 vezes ao dia, antes do desjejum, do almoço e do jantar. O estudo se realizou num período de 12 semanas, para cada paciente e no início e o fim do mesmo foram avaliados peso, composição corpórea por bioimpedância, metabolismo de repouso (por calorimetria), pulso e pressão arterial e eventos adversos. Resultados: Houve perda de peso em todos os grupos, mas o único que perdeu peso significativamente em relação ao grupo placebo foi o que recebeu FPA (p < 0,05). Não houve diferença quanto à composição corpórea e metabolismo de repouso entre os 5 grupos. Conclusão: Em nossa amostra, a FPA se revelou mais eficaz, embora este fato não possa ser atribuído a uma maior queima energética em repouso, já que não houve diferença apreciável no metabolismo de repouso entre os grupos.
Raquitismo hipofosfatêmico: da clínica à genética molecular
Authors: Nunes Adriana B. , Lazaretti-Castro Marise
Published: January 2006

O raquitismo hipofosfatêmico dominante ligado ao cromossomo X é a forma mais comum de raquitismo familial, e caracteriza-se por hipofosfatemia associada a hiperfosfatúria e metabolismo anormal da vitamina D. Existem outras formas de hiperfosfatúrias hereditárias, sugerindo um complexo processo de homeostase do fosfato. Como não está definida qual a lesão básica do distúrbio, torna-se difícil o esclarecimento da fisiopatologia. Recentemente, através da abordagem de clonagem posicional, foi identificado um forte gene candidato, o PEX, que seria o responsável pelo distúrbio. Diversos tipos de mutações no PEX foram encontradas em cerca de 60 famílias. Os recentes avanços genéticos no estudo dessa doença muito têm contribuído para melhorar o entendimento da sua fisiopatologia e do controle do equilíbrio do fosfato.