bluuebunny/crossref_metadata_2025 huggingface dataset:
The HS:1 serostrain ofCampylobacter jejunihas a complex teichoic acid‐like capsular polysaccharide with nonstoichiometric fructofuranose branches andO‐methyl phosphoramidate groups
Authors: McNally David J. , Jarrell Harold C. , Li Jianjun , Khieu Nam H. , Vinogradov Evgeny , Szymanski Christine M. , Brisson Jean‐Robert
Published: August 2005

Recently, the CPS biosynthetic loci for several strains ofCampylobacter jejuniwere sequenced and revealed evidence for multiple mechanisms of structural variation. In this study, the CPS structure for the HS:1 serostrain ofC. jejuniwas determined using mass spectrometry and NMR at 600 MHz equipped with an ultra‐sensitive cryogenically cooled probe. Analysis of CPS purified using a mild enzymatic method revealed a teichoic acid‐like [‐4)‐α‐d‐Galp‐(1–2)‐(R)‐Gro‐(1‐P]n, repeating unit, where Gro is glycerol. Two branches at C‐2 and C‐3 of galactose were identified as β‐d‐fructofuranoses substituted at C‐3 with CH3OP(O)(NH2)(OR) groups. Structural heterogeneity was due to nonstoichiometric glycosylation at C‐3 of galactose and variable phosphoramidate groups. Identical structural features were found for cell‐bound CPS on intact cells using proton homonuclear and31P heteronuclear two‐dimensional HR‐MAS NMR at 500 MHz. In contrast, spectroscopic data acquired for hot water/phenol purified CPS was complicated by the hydrolysis and subsequent loss of labile groups during extraction. Collectively, the results of this study established the importance of using sensitive isolation techniques and HR‐MAS NMR to examine CPS structuresin vivowhen labile groups are present. This study uncovered how incorporation of variableO‐methyl phosphoramidate groups on nonstoichiometric fructose branches is used inC. jejuniHS:1 as a strategy to produce a highly complex polysaccharide from its small CPS biosynthetic locus and a limited number of sugars.
Megalin binds and mediates cellular internalization of folate binding protein
Authors: Birn Henrik , Zhai Xiaoyue , Holm Jan , Hansen Steen I. , Jacobsen Christian , Christensen Erik I. , Moestrup Søren K.
Published: August 2005

Folate is an essential vitamin involved in a number of biological processes. High affinity folate binding proteins (FBPs) exist both as glycosylphosphatidylinositol‐linked, membrane associated folate binding proteins and as soluble FBPs in plasma and some secretory fluids such as milk, saliva and semen. The function and significance of FBPs are unresolved, however, it has been suggested that they may facilitate folate uptake, e.g. during suckling. The present study shows that megalin, a large, multiligand endocytic receptor and member of the low‐density lipoprotein‐receptor family, is able to bind and mediate cellular uptake of FBP. Surface plasmon resonance analysis shows binding of bovine and human milk FBP to immobilized megalin, but not to low density lipoprotein receptor related protein. Binding of 125I‐labeled folate binding protein (FBP) to sections of kidney proximal tubule, known to express high levels of megalin, is inhibitable by excess unlabeled FBP and by receptor associated protein, a known inhibitor of binding to megalin. Immortalized rat yolk sac cells, representing an established model for studying megalin‐mediated uptake, reveal 125I‐labeled FBP uptake which is inhibited by receptor associated protein and by antimegalin antibodies. Microinjection of 125I‐labeled FBP into renal tubules in vivo shows proximal tubular uptake by endocytosis. Megalin is expressed in several absorptive epithelia, including intestine and kidney proximal tubule, and thus the present findings provide a mechanism for intestinal and renal endocytic uptake of soluble FBP.
Efficient RNA ligation by reverse‐joined hairpin ribozymes and engineering of twin ribozymes consisting of conventional and reverse‐joined hairpin ribozyme units
Authors: Ivanov Sergei A. , Vauléon Stéphanie , Müller Sabine
Published: August 2005

In recent years major progress has been made in elucidating the mechanism and structure of catalytic RNA molecules, and we are now beginning to understand ribozymes well enough to turn them into useful tools. Work in our laboratory has focused on the development of twin ribozymes for site‐specific RNA sequence alteration. To this end, we followed a strategy that relies on the combination of two ribozyme units into one molecule (hence dubbed twin ribozyme). Here, we present reverse‐joined hairpin ribozymes that are structurally optimized and which, in addition to cleavage, catalyse efficient RNA ligation. The most efficient variant ligated its appropriate RNA substrate with a single turnover rate constant of 1.1 min−1 and a final yield of 70%. We combined a reverse‐joined hairpin ribozyme with a conventional hairpin ribozyme to create a twin ribozyme that mediates the insertion of four additional nucleotides into a predetermined position of a substrate RNA, and thus mimics, at the RNA level, the repair of a short deletion mutation; 17% of the initial substrate was converted to the insertion product.
GeV gamma-rays and TeV neutrinos from very massive compact binary systems: the case of WR 20a
Authors: Bednarek W.
Published: August 2005

Massive Wolf—Rayet stars in a compact binary system are characterized by very strong winds which collide, creating a shock wave. If the wind nuclei, from helium up to oxygen, accelerated at the shock can reach large enough energies, they suffer disintegration in collisions with soft thermal radiation from the massive stars injecting relativistic protons and neutrons. Protons collide with the matter of the wind and a fraction of neutrons collide with the massive stars producing γ-rays and neutrinos via decay of pions. We calculate γ-ray fluxes from inverse Compton e± pair cascades initiated by primary γ-rays and leptons, which are produced by protons, and the neutrino fluxes, produced by protons and neutrons, for the example compact massive binary WR 20a. From normalization of these cascade γ-ray spectra to the fluxes of the EGRET sources 2EG J1021 − 5835 and 2EG J1049 − 5847 observed in the direction of WR 20a, we conclude that this massive binary can be detected by the IceCube type of neutrino detector. The estimated muon neutrino event rate inside the 1-km2 detector during 1 year is between a few and a few tens, depending on the spectrum of accelerated nuclei.
Rumours: constructive or corrosive
Authors: Robertson R G
Published: August 2005

There is an ever-greater emphasis on the maintenance of professional standards in communication among medical professionals. Much of the focus to date revolves around discourse between patients and families in the clinical arena and reflects standards developed by accrediting agencies and the government. Little has been written about the communication among professionals occurring in the administrative milieu that is largely unseen by those not engaged in the direct provision of or receipt of medical care. That rumours are a part of the interactive discourse is likely not unfamiliar to most in academia. Their potential for damage to the workplace and individuals is very real and requires recognition and in some situations, corporate action. There are options to reduce the likelihood of these kinds of communications and to manage them actively when they occur. What may result is an environment that leads to greater organisational confidence and individual productivity.
EXTRACTION OF ILLUMINATED SOLAR CELL AND SCHOTTKY DIODE PARAMETERS USING A GENETIC ALGORITHM
Authors: SELLAI A. , OUENNOUGHI Z.
Published: August 2005

Details concerning the implementation of a versatile genetic algorithm are presented. Solar cell and Schottky diode model parameters are extracted based on the fitness of experimental data to theoretical curves simulated in the framework of certain physical processes and the use of this genetic algorithm. The method is shown to be a reliable alternative to conventional numerical techniques in fitting experimental data to model calculations and the subsequent determination of model related parameters. It is demonstrated, through two examples in particular, that some of the drawbacks associated with the conventional methods can be circumvented if a genetic algorithm is used instead. For instance, a good initial guess is not a critical requirement for convergence and an initial broad range for each of the fitting parameters is enough to achieve reasonably good fits.
A HIGH-ACCURATE AND EFFICIENT OBRECHKOFF FIVE-STEP METHOD FOR UNDAMPED DUFFING'S EQUATION
Authors: ZHAO DEYIN , WANG ZHONGCHENG , DAI YONGMING , WANG YUAN
Published: August 2005

In this paper, we present a five-step Obrechkoff method to improve the previous two-step one for a second-order initial-value problem with the oscillatory solution. We use a special structure to construct the iterative formula, in which the higher-even-order derivatives are placed at central four nodes, and show there existence of periodic solutions in it with a remarkably wide interval of periodicity, [Formula: see text]. By using a proper first-order derivative (FOD) formula to make this five-step method to have two advantages (a) a very high accuracy since the local truncation error (LTE) of both the main structure and the FOD formula are the same as O (h14); (b) a high efficiency because it avoids solving a polynomial equation with degree-nine by Picard iterative. By applying the new method to the well-known problem, the nonlinear Duffing's equation without damping, we can show that our numerical solution is four to five orders higher than the one by the previous Obrechkoff two-step method and it takes only 25% of CPU time required by the previous method to fulfil the same task. By using the new method, a better "exact" solution is found by fitting, whose error tolerance is below 5×10-15, than the one widely used in the lectures, whose error tolerance is below 10-11.
STRENGTH DISTRIBUTION IN DERIVATIVE NETWORKS
Authors: DA FONTOURA COSTA LUCIANO , TRAVIESO GONZALO
Published: August 2005

This article describes a complex network model whose weights are proportional to the difference between uniformly distributed "fitness" values assigned to the nodes. It is shown both analytically and experimentally that the strength density (i.e., the weighted node degree) for this model, called derivative complex networks, follows a power law with exponent γ<1 if the fitness has an upper limit and γ>1 if the fitness has no upper limit but a positive lower limit. Possible implications for neuronal networks topology and dynamics are also discussed.
SURFACE TENSION AND INTERFACIAL FLUCTUATIONS IN d-DIMENSIONAL ISING MODEL
Authors: KAUPUŽS J.
Published: August 2005

The surface tension of rough interfaces between coexisting phases in 2D and 3D Ising models are discussed in view of the known results and some original calculations presented in this paper. The results are summarized in a formula, which allows to interpolate the corrections to finite-size scaling between two and three dimensions. The physical meaning of an analytic continuation to noninteger values of the spatial dimensionality d is discussed. Lattices and interfaces with properly defined fractal dimensions should fulfil certain requirements to possibly have properties of an analytic continuation from d-dimensional hypercubes. Here 2 appears as the marginal value of d below which the (d -1)-dimensional interface splits in disconnected pieces. Some phenomenological arguments are proposed to describe such interfaces. They show that the character of the interfacial fluctuations at d< 2 is not the same as provided by a formal analytic continuation from d-dimensional hypercubes with d≥2. It, probably, is true also for the related critical exponents.
SZNAJD MODEL WITH SYNCHRONOUS UPDATING ON COMPLEX NETWORKS
Authors: TU YU-SONG , SOUSA A. O. , KONG LING-JIANG , LIU MU-REN
Published: August 2005

We analyze the evolution of Sznajd Model with synchronous updating in several complex networks. Similar to the model on square lattice, we have found a transition between the state with nonconsensus and the state with complete consensus in several complex networks. Furthermore, by adjusting the network parameters, we find that a large clustering coefficient does not favor development of a consensus. In particular, in the limit of large system size with the initial concentration p =0.5 of opinion +1, a consensus seems to be never reached for the Watts–Strogatz small-world network, when we fix the connectivity k and the rewiring probability ps; nor for the scale-free network, when we fix the minimum node degree m and the triad formation step probability pt.
SYNCHRONIZATION OF SOME KIND OF PDE CHAOTIC SYSTEMS BY INVARIANT MANIFOLD METHOD
Authors: XIE LINGLI , ZHAO YI
Published: August 2005

In this paper, we are concerned with the complete and generalized synchronization problem for some kind of PDE chaotic systems. The criteria for the existence of synchronization manifold is given in a look-like general framework by invariant manifold method. The corresponding optimization calculation problems and procedures are proposed.
SYNCHRONIZATION CONTROL FOR A CLASS OF CHAOTIC SYSTEMS WITH UNCERTAINTIES
Authors: YAU HER-TERNG , LIN JUI-SHENG , YAN JUN-JUH
Published: August 2005

This paper investigates the chaos synchronization problem for a class of uncertain master-slave chaotic systems. Based on the variable structure control theory, a strategy is proposed to guarantee the occurrence of a sliding mode motion of error states when the proposed control law is applied. As expected, the error state is able to drive to zero with match external uncertainties or into a predictable neighborhood of zero with mismatch external uncertainties. Furthermore, a modified continuous sliding mode controller is also proposed to avoid the chattering. Examples of Lorenz system and Chua's circuit are presented to demonstrate the obtained results.
ON THE GENERATION OF CHAOTIC BEATS IN SIMPLE NONAUTONOMOUS CIRCUITS
Authors: CAFAGNA DONATO , GRASSI GIUSEPPE
Published: August 2005

In this Letter, attention is focused on the dynamics of a second-order nonlinear circuit driven by two sinusoidal signals. The early results reported herein show that the application of signals with slightly different frequencies enables the phenomenon of chaotic beats to be generated. In particular, the beats dynamics are analyzed both in time-domain and state-space, confirming the chaotic behavior of the proposed circuit.
BORDER COLLISION BIFURCATIONS IN THE EVOLUTION OF MUTUALISTIC INTERACTIONS
Authors: DERCOLE FABIO
Published: August 2005

The paper describes the slow evolution of two adaptive traits that regulate the interactions between two mutualistic populations (e.g. a flowering plant and its insect pollinator). For frozen values of the traits, the two populations can either coexist or go extinct. The values of the traits for which populations extinction is guaranteed are therefore of no interest from an evolutionary point of view. In other words, the evolutionary dynamics must be studied only in a viable subset of trait space, which is bounded due to the physiological cost of extreme trait values. Thus, evolutionary dynamics experience so-called border collision bifurcations, when a system invariant in trait space hits the border of the viable subset. The unfolding of standard and border collision bifurcations with respect to two parameters of biological interest is presented. The algebraic and boundary-value problems characterizing the border collision bifurcations are described together with some details concerning their computation.
TWELVE LIMIT CYCLES IN A CUBIC CASE OF THE 16th HILBERT PROBLEM
Authors: YU P. , HAN M.
Published: August 2005

In this paper, we prove the existence of twelve small (local) limit cycles in a planar system with third-degree polynomial functions. The best result so far in literature for a cubic order planar system is eleven limit cycles. The system considered in this paper has a saddle point at the origin and two focus points which are symmetric about the origin. This system was studied by the authors and shown to exhibit ten small limit cycles: five around each of the focus points. It will be proved in this paper that the system can have twelve small limit cycles. The major tasks involved in the proof are to compute the focus values and solve coupled enormous large polynomial equations. A computationally efficient perturbation technique based on multiple scales is employed to calculate the focus values. Moreover, the focus values are perturbed to show that the system can exactly have twelve small limit cycles.
THE CNN PARADIGM: SHAPES AND COMPLEXITY
Authors: ARENA PAOLO , BUCOLO MAIDE , FAZZINO STEFANO , FORTUNA LUIGI , FRASCA MATTIA
Published: August 2005

The paper stresses the universal role that Cellular Nonlinear Networks (CNNs) are assuming today. It is shown that the dynamical behavior of 3D CNN-based models allows us to approach new emerging problems, to open new research frontiers as the generation of new geometrical forms and to establish some links between art, neuroscience and dynamical systems.
A SECURITY BASED MODEL FOR MOBILE AGENT SOFTWARE SYSTEMS
Authors: XU HAIPING , ZHANG ZHIGUO , SHATZ SOL M.
Published: August 2005

Security modeling for agents has been one of the most challenging issues in developing practical mobile agent software systems. In the past, researchers have developed mobile agent systems with emphasis either on protecting mobile agents from malicious hosts or protecting hosts from malicious agents. In this paper, we propose a security based mobile agent system architecture that provides a general solution to protecting both mobile agents and agent hosts in terms of agent communication and agent migration. We present a facilitator agent model that serves as a middleware for secure agent communication and agent migration. The facilitator agent model, as well as the mobile agent model, is based on agent-oriented G-nets — a high level Petri net formalism. To illustrate our formal modeling technique for mobile agent systems, we provide an example of agent migration to show how a design error can be detected.
ANALYZING THE NONLINEAR TIME SERIES OF TURBULENT FLOWS WITH KERNEL INTERVAL REGRESSION MACHINE
Authors: HWANG CHANGHA , HONG DUG HUN
Published: August 2005

The turbulent flow consists of coherent time- and space-organized vortical structures with a particular formation and instability cycle. Research has already shown that some dynamic systems and experimental models still cannot provide a good nonlinear analysis of turbulent time series because in the real turbulent flow there exist very complicated nonlinear behaviors affected by many vague factors. An approach of fuzzy piecewise regression analysis has been proposed to predict the nonlinear time series of turbulent flows. In this paper, we propose kernel interval regression machine for nonlinear time series analysis of turbulent flows. The proposed method applies the kernel trick to interval regression analysis in terms of the inner products of input vectors. In order to indicate the performance of this method, we present an example of predicting the near-wall turbulence time series as a verifiable model. Furthermore, we compare this method with fuzzy piecewise regression model. Experimental results show that the proposed method is very attractive for the turbulence time series in nonlinear analysis and in fuzzy environments.
GRAPHICAL INTERPRETATION OF THE TWOFOLD INTEGRAL AND ITS GENERALIZATION
Authors: NARUKAWA YASUO , TORRA VICENÇ
Published: August 2005

In this work we define a generalization of the twofold integral (generalization of the Choquet and Sugeno integrals) that operates in an arbitrary universal set. A graphical representation of this integral is also introduced.
A MATHEMATICAL PROGRAMMING APPROACH TO FUZZY TANDEM QUEUES
Authors: CHEN SHIH-PIN
Published: August 2005

Tandem queueing models play an important role in many real world systems such as computer systems, production lines, and service systems. This paper proposes a procedure to construct the membership functions of the performance measures in tandem queueing systems, in that the arrival rate and service rates are fuzzy numbers. The basic idea is to transform a fuzzy tandem queue to a family of crisp tandem queues by applying the α -cut approach. Then on the basis of α -cut representation and the extension principle, a pair of mathematical programs is formulated to describe this family of crisp tandem queues, via which the membership functions of the performance measures are derived. Two numerical examples are solved successfully to demonstrate the validity of the proposed approach. Since the performance measures are expressed by membership functions rather than by crisp values, the fuzziness of input information is completely conserved. Thus the proposed approach for fuzzy systems can represent the system more accurately, and more information is provided for designing queueing systems. The successful extension of tandem queues to fuzzy environments permits tandem queueing models to have wider applications.
INTERVAL METHODS IN KNOWLEDGE REPRESENTATION
Authors: KREINOVICH VLADIK
Published: August 2005

This section is maintained by Vladik Kreinovich. Please send your abstracts (or copies of papers that you want to see reviewed here) to vladik@cs.utep.edu, or by regular mail to: Vladik Kreinovich, Department of Computer Science, University of Texas at El Paso, El Paso, TX 79968, USA.
ELASTICAS AND BUCKLING LOADS OF SHEAR DEFORMABLE TAPERED COLUMNS
Authors: LEE BYOUNG KOO , CARR ATHOL J. , LEE TAE EUN , AHN DAE SOON
Published: August 2005

This paper deals with the geometrical nonlinear analyses of buckled columns. Differential equations governing the elasticas of buckled columns are derived, in which both the effects of taper type and shear deformation are included. Three kinds of taper types are considered, i.e. breadth, depth and square tapers. Differential equations are solved numerically to obtain the deflection of elasticas and the buckling loads of such columns. Both clamped ends and hinged ends are considered. The effects of shear deformation on the deflection of elasticas of buckled columns and on the buckling loads of columns are investigated extensively. The buckling load equations for uniform columns are expressed as a function of the implicit shear effect. Experimental studies are presented that complement the theoretical results of nonlinear responses of the elasticas.
John Maynard Smith
Authors: Michod Richard E.
Published: August 2005

John Maynard Smith was one of the most original thinkers in evolutionary biology of the post neo-Darwinian synthesis age. He was able to define new problems with clarity and by doing so open up new research directions. He did this in a number of areas including game theory and evolution, the evolution of sex, animal behavior, evolutionary transitions and molecular evolution. Although he is best known for his research and his ideas, he was a great expositor and wrote many books, including introductory texts in the areas of evolution and genetics, ecology and mathematical modeling, as well as advanced expositions of research problems.
Evolutionary Genetics of Reproductive Behavior inDrosophila: Connecting the Dots
Authors: Markow Therese Ann , O'Grady Patrick M.
Published: August 2005

Species of the genus Drosophila exhibit enormous variation in all of their reproductive behaviors: resource use and specialization, courtship signaling, sperm utilization, and female remating. The genetic bases of this variability and its evolution are poorly understood. At the same time, Drosophila comparative genomics now has developed to a point at which approaches previously only possible with D. melanogaster can be exploited to address these questions. We have taken advantage of the known phylogenetic relationships of this group of flies not only to place these behaviors in an evolutionary framework, but to provide a roadmap for future genetic studies.
The existence of positive solutions for an ellipticboundary value problem
Authors: Afrouzi G. A.
Published: August 2005

By using the mountain pass lemma, we study the existence of
positive solutions for the equation −Δu(x) = λ(u|u| + u)(x) for x ∈ Ω together with Dirichlet
boundary conditions and show that for every λ < λ1,
where λ1 is the first eigenvalue of −Δu = λu in Ω with the Dirichlet boundary conditions, the equation
has a positive solution while no positive solution exists for
λ ≥ λ1.
Jordan automorphisms, Jordan derivations of generalizedtriangular matrix algebra
Authors: Driss Aiat Hadj Ahmed , l′Moufadal Ben Yakoub
Published: August 2005

We investigate Jordan automorphisms and Jordan derivations of a
class of algebras called generalized triangular matrix algebras. We prove that any
Jordan automorphism on such an algebra is either an automorphism
or an antiautomorphism and any Jordan derivation on such an
algebra is a derivation.
Accumulation of BCL10 at the Perinuclear Region is Required for the BCL10-Mediated Nuclear Factor-Kappa B Activation
Authors: Nakamura Kyoko , Senda Takao , Sato Kenzo , Mori Shigeo , Moriyama Masatsugu
Published: August 2005

Objectives: The dysregulated overexpression of BCL10 that results from a specific chromosomal translocation t(1;14)(p22;q32) in mucosa-associated lymphoid tissue lymphoma has been shown to activate nuclear factor (NF)-ĸB, which may promote growth and survival in tumor cells. Accordingly, the molecular mechanisms underlying NF-ĸB activation may be responsible for lymphomagenesis. The aim of this study was to determine the molecular mechanisms underlying NF-ĸB activation by BCL10 overexpression. Methods: HeLa or COS-1 cells were transfected with BCL10, intracellular localization of BCL10 and the activation of NF-ĸB were analyzed. Results: BCL10 expressed at a high level exhibited a filamentous distribution at the perinuclear region, whereas BCL10 at a low level of expression displayed a diffuse cytoplasmic distribution. Furthermore, the BCL10-mediated NF-ĸB activation was efficiently inhibited by a Ca2+ chelating agent or a Ca2+ channel blocker. We also found that amino acids (107–119) of BCL10 are required for the formation of filamentous structures at the perinuclear region and NF-ĸB activation. Conclusion: These findings suggest that the filamentous pattern of overexpressed BCL10 at the perinuclear region adjacent to the endoplasmic reticulum is important for the BCL10-mediated NF-ĸB activation.
Loss of Heterozygosity on Chromosome 10p14–p15 in Colorectal Carcinoma
Authors: Shima H. , Hiyama T. , Tanaka S. , Ito M. , Kitadai Y. , Yoshihara M. , Arihiro K. , Chayama K.
Published: August 2005

High frequencies of loss of heterozygosity (LOH) on chromosome 10p14–p15 have been reported in various tumors, including gliomas, pulmonary carcinoid tumors and cervical, hepatic, prostatic and esophageal carcinomas. However, LOH on chromosome 10p14–p15 in colorectal tumors has not been reported. Therefore, we examined LOH on chromosome 10p14–p15 in 60 colorectal carcinomas (21 superficial and 39 advanced types) by microsatellite assay. Three microsatellite loci, D10S191 (10p14), D10S558 and D10S249 (10p15) were examined by polymerase chain reaction [early colorectal carcinomas, LOH of markers D10S191 (36%), D10S558 (7%) and D10S249 (11%), and in advanced colorectal carcinomas, LOH of markers D10S191 (20%), D10S558 (13%) and D10S249 (33%)]. There were no significant associations between LOH on chromosome 10p14–p15 and clinicopathologic features, including patient age, sex, tumor location, depth of invasion, histologic type, lymph node metastasis and prognosis. These data suggest that a putative tumor suppressor gene associated with colorectal carcinogenesis may be located on chromosome 10p14–p15 and that alteration of this gene may be involved in the development but not progression of colorectal tumors.
Plasma Ghrelin in Anorexia, Bulimia, and Binge-Eating Disorder: Relations with Eating Patterns and Circulating Concentrations of Cortisol and Thyroid Hormones
Authors: Troisi Alfonso , Di Lorenzo Giorgio , Lega Ilaria , Tesauro Manfredi , Bertoli Aldo , Leo Roberto , Iantorno Micaela , Pecchioli Chiara , Rizza Stefano , Turriziani Mario , Lauro Renato , Siracusano Alberto
Published: August 2005

The present study was designed to investigate the relations between plasma ghrelin concentrations, eating patterns, and circulating concentrations of cortisol and thyroid hormones in women with anorexia nervosa, bulimia nervosa, and binge-eating disorder. The patterns of disordered eating behavior were assessed using the Eating Attitudes Test (EAT-26) and the Bulimia Test-Revised (BULIT-R). In women with eating disorders, but not in healthy control women, plasma ghrelin concentrations were negatively correlated with body mass index (BMI) and plasma concentrations of thyreotropin (TSH), free T3 and free T4, and positively correlated with plasma concentrations of cortisol. The ghrelin concentrations of women with binge-eating and purging behavior were significantly lower than those of women with anorexia nervosa, restricting type, and there was a negative relation between the frequency and severity of binge-eating and purging behavior, as measured by the BULIT-R total score, and ghrelin concentrations. In a multivariate regression model controlling for the confounding effects of body mass index (BMI) and age, higher ghrelin concentrations were correlated with lower BULIT-R total scores. The results of this study did not confirm the hypothesis advanced in previous studies that ghrelin concentrations are higher in patients with binge-eating/purging forms of eating disorders. Based on these data, we suggest that, in women with eating disorders, ghrelin concentrations best reflect nutritional status rather than specific patterns of disordered eating behavior.
Role of the Central Amygdala in Modulating the Pituitary-Adrenocortical and Clinical Responses in Experimental Herpes Simplex Virus-1 Encephalitis
Authors: Weidenfeld Joseph , Itzik Anna , Goshen Irit , Yirmiya Raz , Ben-Hur Tamir
Published: August 2005

The amygdala is known to regulate neuroendocrine and behavioral responses to a variety of stimuli. Herpes simplex virus-1 (HSV-1) is the common cause of viral encephalitis, manifested by hypothalamic-pituitary-adrenal (HPA) axis activation, fever, hypermotor activity and aggression. We examined here the role of the central amygdala (cAMG) in regulating the HPA axis function, febrile and behavioral responses to HSV-1 infection in rats. Bilateral electrolytic lesions were performed in the cAMG. HSV-1 encephalitis was induced by intracerebroventricular (ICV) inoculation of purified virions. Motor activity and body temperature were examined by a biotelemetric system. ICV inoculation of HSV-1 caused a marked time-dependent increase in serum corticotropin (ACTH) and corticosterone at 4 and 24 h post-infection. These responses were attenuated in rats with bilateral lesions of the cAMG. HSV-1 infection induced fever, motor hyperactivity and aggressive behavior. These responses were also attenuated in rats with cAMG lesions. The cAMG plays an important role in mediating the neuroendocrine, febrile and behavioral responses to HSV-1 infection.
Cocaine- and Amphetamine-Related Transcript Is Involved in the Orexigenic Effect of Endogenous Anandamide
Authors: Osei-Hyiaman Douglas , Depetrillo Michael , Harvey-White Judith , Bannon Anthony W. , Cravatt Benjamin F. , Kuhar Michael J. , Mackie Ken , Palkovits Miklós , Kunos George
Published: August 2005

Endocannabinoids acting at CB1 cannabinoid receptors (CB1) increase appetite. In view of the predominant presynaptic localization of CB1 in the brain, we tested the hypothesis that the orexigenic effect of endocannabinoids involves inhibition of the release of a tonically active anorexigenic mediator, such as the peptide product of the cocaine- and amphetamine-related transcript (CART). The CB1 antagonist rimonabant inhibited food intake in food-restricted wild-type mice, but not in their CART-deficient littermates. Mice deficient in fatty acid amide hydrolase (FAAH), the enzyme responsible for the in vivo metabolism of the endocannabinoid anandamide, have reduced levels of CART-immunoreactive nerve fibers and terminals in several brain regions implicated in appetite control, including the arcuate, dorsomedial and periventricular nuclei of the hypothalamus, the amygdala, the bed nucleus of the stria terminalis and the nucleus accumbens, and treatment of FAAH–/– mice with rimonabant, 3 mg/kg/day for 7 days, increased CART levels toward those seen in FAAH+/+ wild-type controls. In contrast, no difference in the density of CART-immunoreactive fibers was observed in the median eminence and the paraventricular nucleus of FAAH+/+ and FAAH–/– mice. Acute treatment of wild-type mice with the cannabinoid agonist HU-210 resulted in elevated CART levels in the dorsomedial nucleus and the shell portion of the nucleus accumbens. These observations are compatible with CART being a downstream mediator of the CB1-mediated orexigenic effect of endogenous anandamide.
Interleukin-11 Reduces Renal Injury and Glomerular NF-Kappa B Activity in Murine Experimental Glomerulonephritis
Authors: Lai P.C. , Smith J. , Bhangal G. , Chaudhry K.A. , Chaudhry A.N. , Keith Jr. J.C. , Tam F.W.K. , Pusey C.D. , Cook H.T.
Published: August 2005

Background/Aims: There is now considerable evidence implicating T cells and macrophages in glomerular injury in crescentic glomerulonephritis. Recently, it has been shown that interleukin-11 (IL-11) has an immune modulatory function through its effect on both macrophages and T cells. We, therefore, examined the therapeutic effect of IL-11 in a murine model of experimental glomerulonephritis. Method: Accelerated nephrotoxic nephritis was induced in C57BL/6 mice. IL-11 at a dose of 0.5 mg/kg/day (n = 10) in vehicle was given daily subcutaneously from the day of sensitization until day 14 after initiation of glomerulonephritis. Control mice (n = 10) received injection of vehicle alone with the same schedule. Results: IL-11 treatment markedly decreased albuminuria (6.2 ± 1.9 vs. 18.2 ± 4.5 mg/day, p < 0.05), the number of glomerular macrophages (1.1 ± 0.2 vs. 1.7 ± 0.3 cells/glomerular cross-section, p < 0.05) and glomerular fibrin deposition (fibrin score 0.9 ± 0.3 vs. 2 ± 0.3, p < 0.05). There was no difference in the glomerular T cell numbers between the IL-11-treated and the vehicle group. Glomerular NF-ĸB activity was markedly suppressed by 75% in the treated group (p = 0.0015). Conclusion: In this study, we provide the first in vivo evidence that IL-11 treatment decreases glomerular NF-ĸB activity and reduces renal injury in experimental glomerulonephritis.
Prognostic Value of Dobutamine Stress Myocardial Contrast Perfusion Echocardiography
Authors: Tsutsui Jeane M. , Elhendy Abdou , Anderson James R. , Xie Feng , McGrain Anna C. , Porter Thomas R.
Published: August 2005

Background—

Myocardial perfusion (MP) imaging with real-time contrast echocardiography (RTCE) improves the sensitivity of dobutamine stress echocardiography for detecting coronary artery disease. Its prognostic value is unknown. We sought to determine the value of MP and wall motion (WM) analysis during dobutamine stress echocardiography in predicting the outcome of patients with known or suspected coronary artery disease.

Methods and Results—

We retrospectively studied 788 patients with RTCE during dobutamine stress echocardiography using intravenous commercially available contrast agents. The incremental prognostic value of MP imaging over clinical risk factors and other echocardiographic data was examined through the use of a log-likelihood test (Cox model). During a median follow-up of 20 months, 75 events (9.6%) occurred (58 deaths, 17 nonfatal myocardial infarctions). Abnormal MP had significant incremental value over clinical factors, resting ejection fraction, and WM responses in predicting events (
P
<0.001). By multivariate analysis, the independent predictors of death and nonfatal myocardial infarction were resting left ventricular ejection fraction <50% (relative risk [RR], 1.9; 95% CI, 1.2 to 3.2;
P
=0.01), hypercholesterolemia (RR, 0.5; 95% CI, 0.3 to 0.9;
P
=0.01), and abnormal MP (RR, 5.2; 95% CI, 3.0 to 9.0;
P
<0.0001). The 3-year event free survival was 95% for patients with normal WM and MP, 82% for normal WM and abnormal MP, and 68% for abnormal WM and MP.

Conclusion—

MP imaging during dobutamine stress RTCE provides incremental prognostic information in patients with known or suspected coronary artery disease. Patients with normal MP have a better outcome than patients with normal WM.
Subunit Interaction Determines
I
Ks
Participation in Cardiac Repolarization and Repolarization Reserve
Authors: Silva Jonathan , Rudy Yoram
Published: August 2005

Background—

The role of
I
Ks
, the slow delayed rectifier K
+
current, in cardiac ventricular repolarization has been a subject of debate.

Methods and Results—

We develop a detailed Markov model of
I
Ks
and its α-subunit KCNQ1 and examine their kinetic properties during the cardiac ventricular action potential at different rates. We observe that interaction between KCNQ1 and KCNE1 (the β-subunit) confers kinetic properties on
I
Ks
that make it suitable for participation in action potential repolarization and its adaptation to rate changes; in particular, the channel develops an available reserve of closed states near the open state that can open rapidly on demand.

Conclusions—

Because of its ability to form an available reserve,
I
Ks
can function as a repolarization reserve when
I
Kr
, the rapid delayed rectifier, is reduced by disease or drug and can prevent excessive action potential prolongation and development of arrhythmogenic early afterdepolarizations.
Common Genetic Variation at the Endothelial Nitric Oxide Synthase Locus and Relations to Brachial Artery Vasodilator Function in the Community
Authors: Kathiresan Sekar , Larson Martin G. , Vasan Ramachandran S. , Guo Chao-Yu , Vita Joseph A. , Mitchell Gary F. , Keyes Michelle J. , Newton-Cheh Christopher , Musone Stacy L. , Lochner Amy L. , Drake Jared A. , Levy Daniel , O’Donnell Christopher J. , Hirschhorn Joel N. , Benjamin Emelia J.
Published: August 2005

Background—

Sequence variants at the endothelial nitric oxide synthase (
NOS3
) locus have been associated with endothelial function measures, but replication has been limited.

Methods and Results—

In reference pedigrees, we characterized linkage disequilibrium structure at the
NOS3
locus using 33 common single nucleotide polymorphisms (SNPs). Eighteen SNPs that capture underlying common variation were genotyped in unrelated Framingham Heart Study participants (49.5% women; mean age, 62 years) with measured brachial artery flow-mediated dilation (n=1446) or hyperemic flow velocity (n=1043). Within 3 defined blocks of strong linkage disequilibrium that spanned
NOS3
, 11 SNPs captured >80% of common haplotypic variation. Among men, there were nominally significant associations between 8
NOS3
SNPs (minimum
P
=0.002) and between haplotypes (minimum
P
=0.002) and either flow-mediated dilation or hyperemic flow velocity. In women, we did not observe significant associations between
NOS3
SNPs or haplotypes and endothelial function measures. To correct for multiple testing, we constructed 1000 bootstrapped null data sets and found that empirical probability values exceeded 0.05 for both phenotypes.

Conclusions—

A parsimonious set of SNPs captures common genetic variation at the
NOS3
locus. A conservative interpretation of our results is that, accounting for multiple testing, we did not observe statistically significant relations between
NOS3
sequence variants and endothelial function measures in either sex. The nominal associations of select
NOS3
variants with endothelial function in men (unadjusted for multiple testing) should be viewed as hypothesis-generating observations and may merit testing in other cohorts and experimental designs.
Sources of variation in Affymetrix microarray experiments
Authors: Zakharkin Stanislav O , Kim Kyoungmi , Mehta Tapan , Chen Lang , Barnes Stephen , Scheirer Katherine E , Parrish Rudolph S , Allison David B , Page Grier P
Published: August 2005

Background

A typical microarray experiment has many sources of variation which can be attributed to biological and technical causes. Identifying sources of variation and assessing their magnitude, among other factors, are important for optimal experimental design. The objectives of this study were: (1) to estimate relative magnitudes of different sources of variation and (2) to evaluate agreement between biological and technical replicates.

Results

We performed a microarray experiment using a total of 24 Affymetrix GeneChip®arrays. The study included 4thmammary gland samples from eight 21-day-oldSprague Dawley CDfemale rats exposed to genistein (soy isoflavone). RNA samples from each rat were split to assess variation arising at labeling and hybridization steps. A general linear model was used to estimate variance components. Pearson correlations were computed to evaluate agreement between technical and biological replicates.

Conclusion

The greatest source of variation was biological variation, followed by residual error, and finally variation due to labeling when *.cel files were processed with dChip and RMA image processing algorithms. When MAS 5.0 or GCRMA-EB were used, the greatest source of variation was residual error, followed by biology and labeling. Correlations between technical replicates were consistently higher than between biological replicates.
Dynamic covariation between gene expression and proteome characteristics
Authors: Sharabiani Mansour Taghavi Azar , Siermala Markku , Lehtinen Tommi O , Vihinen Mauno
Published: August 2005

Background

Cells react to changing intra- and extracellular signals by dynamically modulating complex biochemical networks. Cellular responses to extracellular signals lead to changes in gene and protein expression. Since the majority of genes encode proteins, we investigated possible correlations between protein parameters and gene expression patterns to identify proteome-wide characteristics indicative of trends common to expressed proteins.

Results

Numerous bioinformatics methods were used to filter and merge information regarding gene and protein annotations. A new statistical time point-oriented analysis was developed for the study of dynamic correlations in large time series data. The method was applied to investigate microarray datasets for different cell types, organisms and processes, including human B and T cell stimulation, Drosophila melanogaster life span, and Saccharomyces cerevisiae cell cycle.

Conclusion

We show that the properties of proteins synthesized correlate dynamically with the gene expression profile, indicating that not only is the actual identity and function of expressed proteins important for cellular responses but that several physicochemical and other protein properties correlate with gene expression as well. Gene expression correlates strongly with amino acid composition, composition- and sequence-derived variables, functional, structural, localization and gene ontology parameters. Thus, our results suggest that a dynamic relationship exists between proteome properties and gene expression in many biological systems, and therefore this relationship is fundamental to understanding cellular mechanisms in health and disease.
Dalhousie dyspnea scales: construct and content validity of pictorial scales for measuring dyspnea
Authors: McGrath Patrick J , Pianosi Paul T , Unruh Anita M , Buckley Chloe P
Published: August 2005

Background

Because there are no child-friendly, validated, self-report measures of dyspnea or breathlessness, we developed, and provided initial validation, of three, 7-item, pictorial scales depicting three sub-constructs of dyspnea: throat closing, chest tightness, and effort.

Methods

We developed the three scales (Throat closing, Chest tightness, and Effort) using focus groups with 25 children. Subsequently, seventy-nine children (29 children with asthma, 30 children with cystic fibrosis. and 20 children who were healthy) aged 6 to 18 years rated each picture in each series, using a 0–10 scale. In addition, each child placed each picture in each series on a 100-cm long Visual Analogue Scale, with the anchors "not at all" and "a lot".

Results

Children aged eight years or older rated the scales in the correct order 75% to 98% correctly, but children less than 8 years of age performed unreliably. The mean distance between each consecutive item in each pictorial scale was equal.

Conclusion

Preliminary results revealed that children aged 8 to 18 years understood and used these three scales measuring throat closing, chest tightness, and effort appropriately. The scales appear to accurately measure the construct of breathlessness, at least at an interval level. Additional research applying these scales to clinical situations is warranted.
Right ventricular dyssynchrony in patients with pulmonary hypertension is associated with disease severity and functional class
Authors: López-Candales Angel , Dohi Kaoru , Rajagopalan Navin , Suffoletto Matthew , Murali Srinivas , Gorcsan John , Edelman Kathy
Published: August 2005

Background

Abnormalities in right ventricular function are known to occur in patients with pulmonary arterial hypertension.

Objective

Test the hypothesis that chronic elevation in pulmonary artery systolic pressure delays mechanical activation of the right ventricle, termed dyssynchrony, and is associated with both symptoms and right ventricular dysfunction.

Methods

Fifty-two patients (mean age 46 ± 15 years, 24 patients with chronic pulmonary hypertension) were prospectively evaluated using several echocardiographic parameters to assess right ventricular size and function. In addition, tissue Doppler imaging was also obtained to assess longitudinal strain of the right ventricular wall, interventricular septum, and lateral wall of the left ventricle and examined with regards to right ventricular size and function as well as clinical variables.

Results

In this study, patients with chronic pulmonary hypertension had statistically different right ventricular fractional area change (35 ± 13 percent), right ventricular end-systolic area (21 ± 10 cm2), right ventricular Myocardial Performance Index (0.72 ± 0.34), and Eccentricity Index (1.34 ± 0.37) than individuals without pulmonary hypertension (51 ± 5 percent, 9 ± 2 cm2, 0.27 ± 0.09, and 0.97 ± 0.06, p < 0.005, respectively). Furthermore, peak longitudinal right ventricular wall strain in chronic pulmonary hypertension was also different -20.8 ± 9.0 percent versus -28.0 ± 4.1 percent, p < 0.01). Right ventricular dyssynchrony correlated very well with right ventricular end-systolic area (r = 0.79, p < 0.001) and Eccentricity Index (r = 0.83, p < 0.001). Furthermore, right ventricular dyssynchrony correlates with pulmonary hypertension severity index (p < 0.0001), World Health Organization class (p < 0.0001), and number of hospitalizations (p < 0.0001).

Conclusion

Lower peak longitudinal right ventricular wall strain and significantly delayed time-to-peak strain values, consistent with right ventricular dyssynchrony, were found in a small heterogeneous group of patients with chronic pulmonary hypertension when compared to individuals without pulmonary hypertension. Furthermore, right ventricular dyssynchrony was associated with disease severity and compromised functional class.