bluuebunny/crossref_metadata_2025 huggingface dataset:
Wu-Ling-San Formula Inhibits the Crystallization of Calcium OxalateIn Vitro
Authors: Chen Yu-Cheng , Ho Chien-Yi , Chen Lieh-Der , Hsu Sheng-Feng , Chen Wen-Chi
Published: June 2007

Urinary stone disease is a common disease and has a high rate of recurrence. There is no ideal long-term medical treatment to prevent the recurrence of urinary stones. Wu-Ling-San (WLS) formula has been used for centuries in China for long-term treatment of urological diseases. However, no pharmacological studies have been conducted to evaluate its effect on urinary stone disease. Therefore, using a photospectrometer, we studied the effects of WLS on nucleation, growth and aggregation of calcium oxalate in vitro. The results showed that WLS extract significantly slowed the speed of calcium oxalate ( CaOx ) crystal nucleation. WLS extracts at concentrations of 6.25, 12.5, 25, and 50 mg/ml inhibited nucleation of calcium oxalate crystallization by 344, 387, 543, and 943%, respectively. WLS extracts did not inhibit the growth of CaOx crystallization; however, WLS extracts at concentrations of 12.5 and 25 mg/ml significantly inhibited the aggregation of CaOx crystallization by 74.24% and 75.05%, respectively. WLS extract at a concentration of 50 mg/ml inhibited CaOx aggregation by 92.49%. In conclusion, our results indicate that WLS extract inhibited calcium oxalate nucleation and aggregation, and may have the potential to prevent stone recurrence.
SEMI-ONLINE MACHINE COVERING
Authors: CAI SHENG-YI
Published: June 2007

This paper investigates two different semi-online versions of the machine covering, which is the problem of assigning a set of jobs to a system of m(m ≥ 3) identical parallel machines so as to maximize the earliest machine completion time. In the first case, we assume that the largest processing times is known in advance. In the second case, we assume that the total processing times of all jobs is known in advance. For each version we propose a semi-online algorithm and investigate its competitive ratio. The competitive ratio of each algorithm is [Formula: see text], which is shown to be the best possible competitive ratio for each semi-online problem.
MAINTENANCE OF SYSTEMS BY MEANS OF REPLACEMENTS AND REPAIRS: THE CASE OF PHASE-TYPE DISTRIBUTIONS
Authors: MONTORO-CAZORLA DELIA , PÉREZ-OCÓN RAFAEL
Published: June 2007

We present two models for studying a system maintained by means of imperfect repairs before a replacement or a perfect repair is allowed. The operational and repair times follow phase-type distributions. Imperfect repair means that successive operational times decrease and successive repair times increase. Under these assumptions, models that govern the systems are Markov processes, whose structures are determined, and several performance measures are calculated in transient and stationary regime. These models extend other previously studied in the literature. The incorporation of phase-type distributions allows to apply the model to many other distributions. A numerical example illustrates the calculations and allows a comparison of the results.
J FUNCTIONS, NON-NEF TORIC VARIETIES AND EQUIVARIANT LOCAL MIRROR SYMMETRY OF CURVES
Authors: FORBES BRIAN , JINZENJI MASAO
Published: June 2007

We provide a straightforward computational scheme for the equivariant local mirror symmetry of curves, i.e. mirror symmetry for [Formula: see text] for k ≥ 1, and detail related methods for dealing with mirror symmetry of non-nef toric varieties, based on the theorems of Refs. 2 and 13. The basic tools are equivariant I functions and their Birkhoff factorization.
GALACTIC DYNAMICS VIA GENERAL RELATIVITY: A COMPILATION AND NEW DEVELOPMENTS
Authors: COOPERSTOCK F. I. , TIEU S.
Published: June 2007

We consider the consequences of applying general relativity to the description of the dynamics of a galaxy, given the observed flattened rotation curves. The galaxy is modeled as a stationary axially symmetric pressure-free fluid. In spite of the weak gravitational field and the nonrelativistic source velocities, the mathematical system is still seen to be nonlinear. It is shown that the rotation curves for various galaxies as examples are consistent with the mass density distributions of the visible matter within essentially flattened disks. This obviates the need for a massive halo of exotic dark matter. We determine that the mass density for the luminous threshold as tracked in the radial direction is 10-21.75 kg · m -3 for these galaxies and conjecture that this will be the case for other galaxies yet to be analyzed. We present a velocity dispersion test to determine the extent, if of any significance, of matter that may lie beyond the visible/HI region. This is determined by examining the rotation curves at different galactic latitudes, bringing into consideration the global dynamical structure of the galaxy. The demand for global consistency applies not only to our own but also to all proposed models and theories. Various comments and criticisms from colleagues are addressed.
A HYBRID AND HIERARCHICAL APPROACH TO AERIAL IMAGE REGISTRATION
Authors: XU DONGJIANG , KASPARIS TAKIS
Published: June 2007

This paper proposes a hybrid approach to image registration for inferring the affine transformation that best matches a pair of partially overlapping aerial images. The image registration is formulated as a two-stage hybrid approach combining both phase correlation method (PCME) and optical flow equation (OFE) based estimation algorithm in a coarse-to-fine manner. With PCME applied at the highest level of decomposition, the initial affine parameter model could be first estimated. Subsequently, the OFE-based estimation algorithm is incorporated into the proposed hybrid approach using a multi-resolution mechanism. PCME is characterized by its insensitivity to large geometric transform between images, which can effectively guide the OFE-based registration. For image pairs under salient brightness variations, we propose a nonlinear image representation that emphasizes common intensity information, suppresses the non-common information between an image pair, and is suitable for the proposed coarse-to-fine hierarchical iterative processing. Experimental results demonstrate the accuracy and efficiency of our proposed approach using different types of aerial images.
AN INVARIANT SHAPE REPRESENTATION: INTERIOR ANGLE CHAIN
Authors: WANG BIN , CHEN YAN QIU
Published: June 2007

This paper proposes a novel shape representation scheme — Interior Angle Chain (IAC) — which is invariant to translation, rotation and scaling. The proposed method first approximates the contour of a planar shape with an equilateral polygon and then makes a representation using the polygon's interior angle chain. The difference between two shapes is measured by the distance between their IAC's. An algorithm to obtain equilateral polygon approximation and its associated IAC is proposed in this paper. The proposed shape representation scheme has been tested on two benchmarks and applied to lake recognition in SAR (Synthetic Aperture Radar) images. The results show that IAC is an effective shape representation scheme.
RECOGNITION OF PERSIAN ONLINE HANDWRITING USING ELASTIC FUZZY PATTERN RECOGNITION
Authors: HALAVATI RAMIN , SHOURAKI SAEED BAGHERI
Published: June 2007

Persian is a fully cursive handwriting in which each character may take different forms in different parts of the word, characters overlap and there is a wide range of possible styles. These complexities make automatic recognition of Persian a very hard task. This paper presents a novel approach on recognition of such writings systems which is based on the description of input stream by a sequence of fuzzy linguistic terms; representation of character patterns with the same descriptive language; and comparison of inputs with character patterns using a novel elastic pattern matching approach. As there is no general benchmark for recognition of Persian handwriting, the approach has been tested on the set of words in first primary Iranian school books including 1250 words resulting in 78% correct recognition without dictionary and 96% with dictionary.
DEVELOPING MINING-GRID CENTRIC E-FINANCE PORTALS FOR RISK MANAGEMENT AND DECISION MAKING
Authors: HU JIA , ZHONG NING , SHI YONG
Published: June 2007

E-finance industry is rapidly transforming and evolving toward more dynamic, flexible and intelligent solutions. This paper describes a model with dynamic multilevel workflows corresponding to a multilayer Grid architecture. The mining-grid is used for multiaspect analysis in building e-finance portals on the Wisdom Web. The application and research demonstrate that mining-grid centric design is effective for developing intelligent risk management and decision making financial systems.

This paper concentrates on how to develop a mining-grid centric e-finance portal (MGCFP), not only for supplying effective online financial services for both retail and corporate customers, but also for intelligent credit risk management and decision making for financial enterprises and partners.
THE EVOLUTION OF KDD: TOWARDS DOMAIN-DRIVEN DATA MINING
Authors: CAO LONGBING , ZHANG CHENGQI
Published: June 2007

Traditionally, data mining is an autonomous data-driven trial-and-error process. Its typical task is to let data tell a story disclosing hidden information, in which domain intelligence may not be necessary in targeting the demonstration of an algorithm. Often knowledge discovered is not generally interesting to business needs. Comparably, real-world applications rely on knowledge for taking effective actions. In retrospect of the evolution of KDD, this paper briefly introduces domain-driven data mining to complement traditional KDD. Domain intelligence is highlighted towards actionable knowledge discovery, which involves aspects such as domain knowledge, people, environment and evaluation. We illustrate it through mining activity patterns in social security data.
A MULTISTAGE RULE INDUCTION ALGORITHM IN CLASSIFICATION
Authors: SUN JIGUI , LIU HUAWEN , QI CHANGSONG
Published: June 2007

The purpose of this paper is to start a conceptual investigation of approximation rule based on VPRS as a result of the certainty degree of rules in complete information system that cannot exactly express the uncertainty of those in incomplete information system, and then an efficient approximation rule induction algorithm under the rough set framework is presented. Instead of focusing on the minimal rule set, this algorithm hierarchically extracts rules in multistages from data sets to suit changing environments in learning and classification. In addition, a heuristic strategy is employed in the algorithm to improve its performance and reduce the time consumed in inducing. Experiments are carried out, and the results show that the proposed algorithm is effective in inducing rules which can enhance their adaptive capacities.
EMBEDDING POINT SETS INTO PLANE GRAPHS OF SMALL DILATION
Authors: EBBERS-BAUMANN ANNETTE , GRÜNE ANSGAR , KLEIN ROLF , KARPINSKI MAREK , KNAUER CHRISTIAN , LINGAS ANDRZEJ
Published: June 2007

Let S be a set of points in the plane. What is the minimum possible dilation of all plane graphs that contain S? Even for a set S as simple as five points evenly placed on the circle, this question seems hard to answer; it is not even clear if there exists a lower bound > 1. In this paper we provide the first upper and lower bounds for the embedding problem.

1. Each finite point set can be embedded into the vertex set of a finite triangulation of dilation ≤ 1.1247.

2. Each embedding of a closed convex curve has dilation ≥ 1.00157.

3. Let P be the plane graph that results from intersecting n infinite families of equidistant, parallel lines in general position. Then the vertex set of P has dilation [Formula: see text].
LÉVY PROCESSES IN ANIMAL MOVEMENT: AN EVOLUTIONARY HYPOTHESIS
Authors: BARTUMEUS FREDERIC
Published: June 2007

The origin of fractal patterns is a fundamental problem in many areas of science. In ecological systems, fractal patterns show up in many subtle ways and have been interpreted as emergent phenomena related to some universal principles of complex systems. Recently, Lévy-type processes have been pointed out as relevant in large-scale animal movements. The existence of Lévy probability distributions in the behavior of relevant variables of movement, introduces new potential diffusive properties and optimization mechanisms in animal foraging processes. In particular, it has been shown that Lévy processes can optimize the success of random encounters in a wide range of search scenarios, representing robust solutions to the general search problem. These results set the scene for an evolutionary explanation for the widespread observed scale-invariant properties of animal movements. Here, it is suggested that scale-free reorientations of the movement could be the basis for a stochastic organization of the search whenever strongly reduced perceptual capacities come into play. Such a proposal represents two new evolutionary insights. First, adaptive mechanisms are explicitly proposed to work on the basis of stochastic laws. And second, though acting at the individual-level, these adaptive mechanisms could have straightforward effects at higher levels of ecosystem organization and dynamics (e.g. macroscopic diffusive properties of motion, population-level encounter rates). Thus, I suggest that for the case of animal movement, fractality may not be representing an emergent property but instead adaptive random search strategies. So far, in the context of animal movement, scale-invariance, intermittence, and chance have been studied in isolation but not synthesized into a coherent ecological and evolutionary framework. Further research is needed to track the possible evolutionary footprint of Lévy processes in animal movement.
ANALYSIS OF FRACTIONAL DIFFERENTIAL EQUATIONS WITH MULTI-ORDERS
Authors: DENG WEIHUA , LI CHANGPIN , GUO QIAN
Published: June 2007

In this paper, we study two kinds of fractional differential systems with multi-orders. One is a system of fractional differential equations with multi-order, [Formula: see text], [Formula: see text]; the other is a multi-order fractional differential equation, [Formula: see text]. By the derived technique, such two kinds of fractional differential equations can be changed into equations with the same fractional orders providing that the multi-orders are rational numbers, so the known theorems of existence, uniqueness and dependence upon initial conditions are easily applied. And asymptotic stability theorems for their associate linear systems, [Formula: see text], [Formula: see text], and [Formula: see text], [Formula: see text], [Formula: see text], are also derived.
DEVIATION OF THE POWER-LAW BY GEOMETRIC AGING EFFECT
Authors: SHIN J. K. , SHIN G. S.
Published: June 2007

An agent-based model is employed for the study of the group size distributions. A fixed number of homogeneous agents are distributed on a two-dimensional lattice system. The dynamics of the agents is described in terms of the inverse distance potential and the friction factor. From a random initial distribution, the agents move forming groups until all the agents come to a stationary position. For a squared system with L × L cells, the group size distribution showed a well defined power-law behavior up to the cut-off size. But when the system changed to an L × H non-squared one, a "geometric aging effect" emerged. Together with the phase transition, the geometric aging effect is considered to be a generic mechanism of the deviated power-law distributions, such as the "fall-off" and the three-bent-line distributions. The results are discussed in relation to the well-known physical or social phenomena such as the King Effect in the city size distributions, the fall-off distribution of the fish schools, the three-bent-line distributions of the Earth-crossing asteroids and 2D percolation problem.
A HIGH-LEVEL FUZZY PETRI NETS MODEL FOR INTEGRATING QUANTITATIVE AND QUALITATIVE DECISION-MAKING
Authors: LIU KEVIN F. R.
Published: June 2007

A complicated decision-making system usually requires both quantitative and qualitative decision-making tools to collaborate for reaping their benefits concurrently. How to integrate quantitative and qualitative decision-making formalisms with a modeling tool is the focus of this study; hence, a high-level fuzzy Petri net model (HLFPN) is proposed as a unified platform to incorporate fuzzy analytic hierarchy process (FAHP) with fuzzy logic for managing semi-structured decision-making. In the HLFPN model, fuzzy places, fuzzy tokens, weighted arcs and several types of transitions are introduced for the purpose of combining both the FAHP and fuzzy logic. Four types of transitions are identified: (1) synthesis transitions to execute the computation of FAHP; (2) inference transitions to perform fuzzy reasoning; (3) aggregation transitions to combine several fuzzy tokens with the same fuzzy variable; and (4) duplication transitions to reproduce a token as several tokens having the same value. To guide the evolution of the HLFPN, an algorithm is also developed. An example of evaluation the environmental sustainability in 146 countries is used to illustrate the use of the HLFPN for coupling the FAHP and fuzzy logic.
MODELS FOR MULTIPLE ATTRIBUTE DECISION MAKING WITH INTUITIONISTIC FUZZY INFORMATION
Authors: XU Z. S.
Published: June 2007

The intuitionistic fuzzy set (IFS) characterized by a membership function and a non-membership function, was introduced by Atanassov [K. Atanassov, "Intuitionistic fuzzy sets", Fuzzy Sets and Systems 20 (1986) 87–96] as a generalization of Zadeh' fuzzy set [L. A. Zadeh, "Fuzzy Sets", Information and Control 8 (1965) 338–353] to deal with fuzziness and uncertainty. In this paper, we investigate the multiple attribute decision making (MADM) problems, in which the information about attribute weights is incomplete, and the attribute values are expressed in intuitionistic fuzzy numbers (IFNs). We first define the concept of intuitionistic fuzzy ideal solution (IFIS), and then, based on the IFIS and the distance measure, we establish some optimization models to derive the attribute weights. Furthermore, based on the developed models, we develop some procedures for the rankings of alternatives under different situations, and extend the developed models and procedures to handle the MADM problems with interval-valued intuitionistic fuzzy information. Finally, we give some illustrative examples to verify the effectiveness and practicability of the developed models and procedures.
REPRESENTABILITY IN INTERVAL-VALUED FUZZY SET THEORY
Authors: DESCHRIJVER GLAD , CORNELIS CHRIS
Published: June 2007

Interval-valued fuzzy set theory is an increasingly popular extension of fuzzy set theory where traditional [0,1]-valued membership degrees are replaced by intervals in [0,1] that approximate the (unknown) membership degrees. To construct suitable graded logical connectives in this extended setting, it is both natural and appropriate to "reuse" ingredients from classical fuzzy set theory. In this paper, we compare different ways of representing operations on interval-valued fuzzy sets by corresponding operations on fuzzy sets, study their intuitive semantics, and relate them to an existing, purely order-theoretical approach. Our approach reveals, amongst others, that subtle differences in the representation method can have a major impact on the properties satisfied by the generated operations, and that contrary to popular perception, interval-valued fuzzy set theory hardly corresponds to a mere twofold application of fuzzy set theory. In this way, by making the mathematical machinery behind the interval-valued fuzzy set model fully transparent, we aim to foster new avenues for its exploitation by offering application developers a much more powerful and elaborate mathematical toolbox than existed before.
A FUZZY COMPROMISE SOLUTION FOR MULTICRITERIA PROBLEMS
Authors: OPRICOVIC SERAFIM
Published: June 2007

The VIKOR-F method has been developed to solve fuzzy multicriteria problem with conflicting and noncommensurable (different units) criteria. It determines the compromise solution that is the "closest" to the ideal. Imprecision in multicriteria decision making can be modelled using fuzzy set theory to define criteria and the importance of criteria. This method solves problem in a fuzzy environment where both criteria and weights could be fuzzy sets. The triangular fuzzy numbers are used to handle imprecise numerical quantities. It is based on the aggregating fuzzy merit that represents distance of an alternative to the ideal solution. The fuzzy operations and procedures for ranking fuzzy numbers are used in developing the VIKOR-F algorithm. A numerical example illustrates an application of the VIKOR-F method.
GASA: A GRAPH-BASED AUTOMATED NMR BACKBONE RESONANCE SEQUENTIAL ASSIGNMENT PROGRAM
Authors: WAN XIANG , LIN GUOHUI
Published: June 2007

The success in backbone resonance sequential assignment is fundamental to three dimensional protein structure determination via Nuclear Magnetic Resonance (NMR) spectroscopy. Such a sequential assignment can roughly be partitioned into three separate steps: grouping resonance peaks in multiple spectra into spin systems, chaining the resultant spin systems into strings, and assigning these strings to non-overlapping consecutive amino acid residues in the target protein. Separately dealing with these three steps has been adopted in many existing assignment programs, and it works well on protein NMR data with close-to-ideal quality, while only moderately or even poorly on most real protein datasets, where noises as well as data degeneracies occur frequently. We propose in this work to partition the sequential assignment not by physical steps, but only virtual steps, and use their outputs to cross validate each other. The novelty lies in the places, where the ambiguities at the grouping step will be resolved in finding the highly confident strings at the chaining step, and the ambiguities at the chaining step will be resolved by examining the mappings of strings at the assignment step. In this way, all ambiguities at the sequential assignment will be resolved globally and optimally. The resultant assignment program is called Graph-based Approach for Sequential Assignment (GASA), which has been compared to several recent similar developments including PACES, RANDOM, MARS, and RIBRA. The performance comparisons with these works demonstrated that GASA is more promising for practical use.
IDENTIFYING DIFFERENTIALLY EXPRESSED GENES IN TIME-COURSE MICROARRAY EXPERIMENT WITHOUT REPLICATE
Authors: HAN XU , SUNG WING-KIN , FENG LIN
Published: June 2007

Replication of time series in microarray experiments is costly. To analyze time series data with no replicate, many model-specific approaches have been proposed. However, they fail to identify the genes whose expression patterns do not fit the pre-defined models. Besides, modeling the temporal expression patterns is difficult when the dynamics of gene expression in the experiment is poorly understood. We propose a method called Partial Energy ratio for Microarray (PEM) for the analysis of time course microarray data. In the PEM method, we assume the gene expressions vary smoothly in the temporal domain. This assumption is comparatively weak and hence the method is general enough to identify genes expressed in unexpected patterns. To identify the differentially expressed genes, a new statistic is developed by comparing the energies of two convoluted profiles. We further improve the statistic for microarray analysis by introducing the concept of partial energy. The PEM statistic can be easily incorporated into the SAM framework for significance analysis. We evaluated the PEM method with an artificial dataset and two published time course cDNA microarray datasets on yeast. The experimental results show the robustness and the generality of the PEM method in identifying the genes of interest.
BIOMARKER DISCOVERY AND VISUALIZATION IN GENE EXPRESSION DATA WITH EFFICIENT GENERALIZED MATRIX APPROXIMATIONS
Authors: LI WENYUAN , PENG YANXIONG , HUANG HUNG-CHUNG , LIU YING
Published: June 2007

In most real-world gene expression data sets, there are often multiple sample classes with ordinals, which are categorized into the normal or diseased type. The traditional feature or attribute selection methods consider multiple classes equally without paying attention to the up/down regulation across the normal and diseased types of classes, while the specific gene selection methods particularly consider the differential expressions across the normal and diseased, but ignore the existence of multiple classes. In this paper, to improve the biomarker discovery, we propose to make the best use of these two aspects: the differential expressions (that can be viewed as the domain knowledge of gene expression data) and the multiple classes (that can be viewed as a kind of data set characteristic). Therefore, we simultaneously take into account these two aspects by employing the 1-rank generalized matrix approximations (GMA). Our results show that GMA cannot only improve the accuracy of classifying the samples, but also provide a visualization method to effectively analyze the gene expression data on both genes and samples. Based on the mechanism of matrix approximation, we further propose an algorithm, CBiomarker, to discover compact biomarker by reducing the redundancy.
DENSITY DOMINATION OF QoS CONTROL IN WIRELESS SENSOR NETWORKS
Authors: ZHOU JUEJIA , MU CHUNDI
Published: June 2007

Wireless sensor networks (WSN) are a kind of networks made of tiny sensing embedded devices with processors, memories and short-range wireless communication modules. They are planted for sensing the area which people mostly care about and to send data of light, pressure, sound, and so on, back to people to make further analyses. Differing from normal linear networks, WSN are usually restricted by energy store, plethoric information flow, and short communication distance. So, there are many research hotpots in WSN such as routing, economization of energy, adaptive self-configuration, etc. Among these aspects, the area of quality of service (QoS) remains largely open. This is due to that the optimal alive sensor nodes number is difficult to determine in a certain focused area which satisfies the requirement of QoS. In order to make an optimal number of nodes to power up in a focused area, the paper proposes the density domination strategy with location information and localized information based on the modified Gur Game which is embedded with gradient mechanism. In the strategies, the base station receives the QoS feedback and gives the dynamic density domination information. The simulation results about the two kinds of density domination strategies are given. The results show that both of the strategies can effectively control the density of power-up nodes and meet the requirement of QoS.
ALGORITHM OF IMM COMBINING KALMAN AND PARTICLE FILTER FOR MANEUVERING TARGET TRACKING
Authors: LIU GUIXI , GAO ENKE , FAN CHUNYU
Published: June 2007

The particle filter can deal with nonlinear/non-Gaussian problems and it has been introduced to the algorithm of the interacting multiple model (IMM) for higher precision. The general IMM based on Kalman filter or extended Kalman filter (IMMEKF) cannot deal with non-Gaussian problems and also does not work as well as the IMM based on the particle filter (IMMPF) for the nonlinear problems. However the problem of the particle filter is its expensive computation, because a particle filter usually has a lot of particles, which will increase the computation load greatly. Here an algorithm of IMM combining the Kalman filter and the particle filter (IMMK-PF) for maneuvering target tracking is proposed to improve the computation efficiency as compared to the IMMPF. For nonlinear/Gaussian problems the new algorithm is expected to have a good performance as the IMMPF, while for linear problems it will perform similarly to the IMMEKF and will work better than the IMMPF.
SYSTEM DESIGNING FOR A SMALL-SCALE AUTONOMOUS HELICOPTER
Authors: CHEN WENBING , LIU MING , GE YUNJIAN
Published: June 2007

This paper presents the design of a relative low-cost and more compatible autonomous helicopter system using HIROBO 50 scale as an experimental platform. Because of the limit of helicopter payload, we choose the MP2128 Autopilot and a number of sensors to build the system and the weight of instrumentation is about 500 g, much less than the payload capability of model helicopter. Thus it is feasible to design the binocular stereo-camera system to achieve full autonomous flight and the whole weight (include power) of instrumentation is about 1500 g. After getting the model of the helicopter using the subspace model identification (SMI) algorithms, we present the structure of fuzzy PID controller.
Vagus nerve integrity and experimental colitis
Authors: Ghia Jean-Eric , Blennerhassett Patricia , Collins Stephen M.
Published: June 2007

Previous studies have identified a counterinflammatory vagal reflex in the context of endotoxic shock. We have extended this observation to show that the vagus confers protection against acute (5 days) colitis induced by dextran sodium sulfate (DSS) or by dinitrobenzene sulfonic acid (DNBS). We have shown that this is mediated via macrophages and involves the suppression of proinflammatory cytokines. In this study, we have examined whether the vagal integrity confers long-lasting protection by studying DNBS- and DSS-induced inflammatory responses in the colon at 9 to 61 days postvagotomy. The integrity of vagotomy was confirmed at all time points using CCK-induced satiety. As previously described in a DNBS and DSS model, vagotomy associated with the pyloroplasty increased all indices of inflammation. Vagotomy increased the disease activity index as well as the macroscopic and histological scores by 75 and 41%, respectively. In addition, myeloperoxidase (MPO) activity, serum levels of C-reactive protein (CRP), and colonic tissue levels of proinflammatory cytokine increased when colitis was induced 9 days postvagotomy. However, these increases in inflammatory indices were substantially diminished in mice with colitis induced 21, 33, and 61 days postvagotomy. This was accompanied by an increased production of interleukin-10, transforming growth factor-β, Forkhead Box P3 (FOXP3) staining in colonic tissue, and serum corticosterone. These findings indicate that although vagal integrity is an important protective factor, other counterinflammatory mechanisms come into play if vagal integrity is compromised beyond 2 wk.
Dexamethasone modulates ErbB tyrosine kinase expression and signaling through multiple and redundant mechanisms in cultured rat hepatocytes
Authors: Scheving Lawrence A. , Buchanan Renee , Krause Michael A. , Zhang Xiuqi , Stevenson Mary C. , Russell William E.
Published: June 2007

Glucocorticoids paradoxically exert both stimulatory and inhibitory effects on the proliferation of cultured rat hepatocytes. We studied the effects of dexamethasone, a synthetic glucocorticoid, on the proliferation of cultured rat hepatocytes. The timing of growth factor addition modified the action of high-dose dexamethasone (10−6 M) on DNA synthesis. When we added transforming growth factor-α at the time of plating, 10−6 M dexamethasone weakly stimulated DNA synthesis by 26% relative to cells cultured in dexamethasone-free media. When we delayed growth factor addition until 24–48 h after plating, 10−6 M dexamethasone inhibited DNA synthesis by 50%. Using immunological methods, we analyzed the expression and signaling patterns of the ErbB kinases in dexamethasone-treated cells. High-dose dexamethasone stabilized the expression of epidermal growth factor receptor (EGFr) and ErbB3, and it suppressed the de novo expression of ErbB2 that occurs during the third and fourth day of culture in 10−8 M dexamethasone. High-dose dexamethasone by 72 h suppressed basal and EGF-associated phosphorylation of ERK and Akt. The reduction in ERK1/2 phosphorylation correlated with suppression of a culture-dependent increase in Son-of sevenless 1 (Sos1) and ERK1/2 expression. High-dose dexamethasone in hepatocytes stabilized or upregulated several inhibitory effectors of EGFr/ErbB2 and ERK, including receptor-associated late transducer (RALT) and MKP-1, respectively. Thus 10−6 M dexamethasone exerts a time-dependent and redundant inhibitory effect on EGFr-mediated proliferative signaling in hepatocytes, targeting not only the ErbB proteins but also their various positive and negative effectors.
Role of glial cell-line derived neurotropic factor family receptor α2 in the actions of the glucagon-like peptides on the murine intestine
Authors: McDonagh Sean C. , Lee Jenny , Izzo Angelo , Brubaker Patricia L.
Published: June 2007

The intestinal glucagon-like peptides GLP-1 and GLP-2 inhibit intestinal motility, whereas GLP-2 also stimulates growth of the intestinal mucosa. However, the mechanisms of action of these peptides in the intestine remain poorly characterized. To determine the role of the enteric nervous system in the actions of GLP-1 and GLP-2 on the intestine, the glial cell line-derived neurotropic factor family receptor α2 (GFRα2) knockout (KO) mouse was employed. The mice exhibited decreased cholinergic staining, as well as reduced mRNA transcripts for substance P-ergic excitatory motoneurons in the enteric nervous system (ENS) ( P < 0.05). Examination of parameters of intestinal growth (including small and large intestinal weight and small intestinal villus height, crypt depth, and crypt cell proliferation) demonstrated no differences between wild-type and KO mice in either basal or GLP-2-stimulated mucosal growth. Nonetheless, KO mice exhibited reduced numbers of synaptophysin-positive enteroendocrine cells ( P < 0.05), as well as a markedly impaired basal gastrointestinal (GI) transit rate ( P < 0.05). Furthermore, acute administration of GLP-1 and GLP-2 significantly inhibited transit rates in wild-type mice ( P < 0.05–0.01) but had no effect in GFRα2 KO mice. Despite these changes, expression of mRNA transcripts for the GLP receptors was not reduced in the ENS of KO animals, suggesting that GLP-1 and -2 modulate intestinal transit through enhancement of inhibitory input to cholinergic/substance P-ergic excitatory motoneurons. Together, these findings demonstrate a role for GFRα2-expressing enteric neurons in the downstream signaling of the glucagon-like peptides to inhibit GI motility, but not in intestinal growth.
Mitochondria are targets for geranylgeranylacetone-induced cardioprotection against ischemia-reperfusion in the rat heart
Authors: Shinohara Tetsuji , Takahashi Naohiko , Kohno Hiroaki , Yamanaka Kunitoshi , Ooie Tatsuhiko , Wakisaka Osamu , Murozono Yukichi , Taniguchi Yayoi , Torigoe Yasuko , Hara Masahide , Shimada Tatsuo , Saikawa Tetsunori , Yoshimatsu Hironobu
Published: June 2007

It has been shown that orally administered geranylgeranylacetone (GGA), an anti-ulcer drug, induces expression of heat shock protein 72 (HSP72) and provides protection against ischemia-reperfusion in rat hearts. The underlying protective mechanisms, however, remain unknown. Mitochondria have been shown to be a selective target for heat stress-induced cardioprotection. Therefore, we hypothesized that preservation of mitochondrial function, owing to an opening of a putative channel in the inner mitochondrial membrane, the mitochondrial ATP-sensitive potassium (mitoKATP) channel, could be involved in GGA- or heat stress-induced cardioprotection against ischemia-reperfusion. Rats were treated with oral GGA or vehicle. Twenty-four hours later, each heart was isolated and perfused with a Langendorff apparatus. GGA-treated hearts showed better functional recovery, and less creatine kinase was released during a 30-min reperfusion period, after 20 min of no-flow ischemia. Concomitant perfusion with 5-hydroxydecanoate (5-HD, 100 μM) or glibenclamide (10 μM) abolished the GGA-induced cardioprotective effect. GGA also showed preserved mitochondrial respiratory function, isolated at the end of the reperfusion period, which was abolished with 5-HD treatment. GGA prevented destruction of the mitochondrial structure by ischemia-reperfusion, as shown by electron microscopy. In cultured cardiomyocytes, GGA induced HSP72 expression and resulted in less damage to cells, including less apoptosis in response to hypoxia-reoxygenation. Treatment with 5-HD abolished the GGA-induced cardioprotective effects but did not affect HSP72 expression. Our results indicate that preserved mitochondrial respiratory function, owing to GGA-induced HSP72 expression, may, at least in part, have a role in cardioprotection against ischemia-reperfusion. These processes may involve opening of the mitoKATP channel.
Preoptic norepinephrine mediates the febrile response of guinea pigs to lipopolysaccharide
Authors: Feleder Carlos , Perlik Vit , Blatteis Clark M.
Published: June 2007

Norepinephrine (NE) microdialyzed in the preoptic area (POA) raises core temperature (Tc) via 1) α1-adrenoceptors (AR), quickly and independently of POA PGE2, and 2) α2-AR, after a delay and PGE2dependently. Since systemic lipopolysaccharide (LPS) activates the central noradrenergic system, we investigated whether preoptic NE mediates LPS fever. We injected LPS (2 μg/kg iv) in guinea pigs prepared with intra-POA microdialysis probes and determined POA cerebrospinal (CSF) NE levels. We similarly microdialyzed prazosin (α1blocker, 1 μg/μl), yohimbine (α2blocker, 1 μg/μl), SC-560 [cyclooxygenase (COX)-1 blocker, 5 μg/μl], acetaminophen (presumptive COX-1v blocker, 5 μg/μl), or MK-0663 (COX-2 blocker, 0.5 μg/μl) in other animals before intravenous LPS and measured CSF PGE2. All of the agents were perfused at 2 μg/min for 6 h. Tcwas monitored constantly. POA NE peaked within 30 min after LPS and then returned to baseline over the next 90 min. Tcincreased within 12 min to a first peak at ∼60 min and to a second at ∼150 min and then declined over the following 2.5 h. POA PGE2followed a concurrent course. Prazosin pretreatment eliminated the first Tcrise but not the second; PGE2rose normally. Yohimbine pretreatment did not affect the first Tcrise, which continued unchanged for 6 h; the second rise, however, was absent, and PGE2levels did not increase. SC-560 and acetaminophen did not alter the LPS-induced PGE2and Tcrises; MK-0663 prevented both the late PGE2and Tcrises. These results confirm that POA NE is pivotal in the development of LPS fever.
Denervation-induced skeletal muscle atrophy is associated with increased mitochondrial ROS production
Authors: Muller Florian L. , Song Wook , Jang Youngmok C. , Liu Yuhong , Sabia Marian , Richardson Arlan , Van Remmen Holly
Published: June 2007

Reactive oxygen species (ROS), especially mitochondrial ROS, are postulated to play a significant role in muscle atrophy. We report a dramatic increase in mitochondrial ROS generation in three conditions associated with muscle atrophy: in aging, in mice lacking CuZn-SOD ( Sod1−/−), and in the neurodegenerative disease, amyotrophic lateral sclerosis (ALS). ROS generation in muscle mitochondria is nearly threefold higher in 28- to 32-mo-old than in 10-mo-old mice and is associated with a 30% loss in gastrocnemius mass. In Sod1−/−mice, muscle mitochondrial ROS production is increased >100% in 20-mo compared with 5-mo-old mice along with a >50% loss in muscle mass. ALS G93A mutant mice show a 75% loss of muscle mass during disease progression and up to 12-fold higher muscle mitochondrial ROS generation. In a second ALS mutant model, H46RH48Q mice, ROS production is approximately fourfold higher than in control mice and is associated with a less dramatic loss (30%) in muscle mass. Thus ROS production is strongly correlated with the extent of muscle atrophy in these models. Because each of the models of muscle atrophy studied are associated to some degree with a loss of innervation, we were interested in determining whether denervation plays a role in ROS generation in muscle mitochondria isolated from hindlimb muscle following surgical sciatic nerve transection. Seven days postdenervation, muscle mitochondrial ROS production increased nearly 30-fold. We conclude that enhanced generation of mitochondrial ROS may be a common factor in the mechanism underlying denervation-induced atrophy.
Upper extremity lymphatic function at rest and during exercise in breast cancer survivors with and without lymphedema compared with healthy controls
Authors: Lane Kirstin N. , Dolan Lianne B. , Worsley Dan , McKenzie Don C.
Published: June 2007

Lymphoscintigraphy was used to measure lymphatic function at rest and during exercise in breast cancer survivors with lymphedema (BCRL, n = 10), breast cancer survivors (BC, n = 10), and controls (Cont, n = 10). After injection of 99mTc-antimony colloid to the hands, subjects rested or performed 12 repeated sets of arm cranking for 2.5 min at 0.6 W/kg followed by 2.5 min of rest. One-minute spot views were taken with a gamma-radiation camera immediately postinjection and every 10 min over 60 min to calculate clearance rate. As well, an upper body scan was taken at 65 min postinjection to measure radiopharmaceutical uptake in the axilla (Ax) and forearm (Fore). All groups displayed similar increases in clearance rate with exercise ( P = 0.000). Ax significantly increased with exercise in Cont only [Cont: (mean ± SD) 4.9 ± 2.6 vs. 7.9 ± 4.2%, P = 0.000; BCRL: 1.4 ± 1.2 vs. 1.7 ± 2.1%, P = 0.531; BC: 3.9 ± 3.4 vs. 5.2 ± 3.2%, P = 0.130], whereas Fore, indicating dermal backflow, significantly increased in BCRL only (BCRL: 2.4 ± 0.87 vs. 4.4 ± 2.0%, P = 0.004; BC: 1.1 ± 0.25 vs. 1.1 ± 0.31%, P = 0.784; Cont: 0.93 ± 0.26 vs. 1.0 ± 0.20%, P = 0.296). The results indicate that, in women with BCRL, exercise causes radiopharmaceuticals to clear from the hand at the same rate as BC and Cont, but, instead of reaching the axilla, a greater amount of activity gets trapped in the dermis of the forearm. BC, meanwhile, have similar lymphatic function as Cont; however, there is a highly variable response that may suggest that some BC subjects may be at risk for developing lymphedema.
Bactericidal/permeability increasing protein attenuates the myocardial inflammation/dysfunction that occurs with burn complicated by subsequent infection
Authors: Horton Jureta W. , Maass David L. , White D. Jean , Minei Joseph P.
Published: June 2007

Intubation and mechanical ventilation after burn contribute to pneumonia-related infection. Although postburn presence or absence of endotoxin has been described, inactivation of Toll-like receptor 4 signaling has been shown to improve postburn organ function, suggesting that LPS participates in burn-related susceptibility to infection. We hypothesized that bactericidal/permeability-increasing protein (rBPI) given postburn would attenuate myocardial inflammation/dysfunction associated with postburn septic challenge given 7 days postburn. Rats were given burn over 40% total body surface area, lactated Ringer 4 ml·kg−1·% burn−1; burns received either vehicle or rBPI, 1 mg·kg−1·h−1for 48 h postburn. Postburn day 7, subgroups of burns and shams were given intratracheal Klebsiella pneumoniae, 4 × 106CFU to produce burn complicated by sepsis; additional sham and burn subgroups received intratracheal vehicle to produce sham sepsis. Vehicle-treated groups: 1) sham burn + sham sepsis 2) sham burn + sepsis, 3) burn + sham sepsis, 4) burn + sepsis. rBPI-treated groups: 5) sham burn + sham sepsis, 6) sham burn + sepsis, 7) burn + sham sepsis, 8) burn + sepsis. Cardiomyocyte cytokine secretion and myocardial function were studied 24 h after septic challenge, postburn day 8. Pneumonia-related infection 8 days after vehicle-treated burn produced myocyte cytokine secretion (pg/ml), indicated by increased myocyte TNF-α, 549 ± 46; IL-1β, 50 ± 8; IL-6, 286 ± 3 levels compared with levels in sham myocytes (TNF-α, 88 ± 11; IL-1β, 7 ± 1; IL-6, 74 ± 10; P < 0.05). Contractile dysfunction was evident from lower left ventricular pressure ±dP/d t values in this group compared with sham. rBPI attenuated myocyte cytokine responses to septic challenge and improved contractile function, suggesting that burn-related mobilization of microbial-like products contribute to postburn susceptibility to infection.
Effect of spaceflight on the subcutaneous venoarteriolar reflex in the human lower leg
Authors: Gabrielsen Anders , Norsk Peter
Published: June 2007

Whenever the legs are lowered in humans, a venoarteriolar reflex is activated by the hydrostatic distension of the venules. Through local axon reflexes, the adjacent arterioles are contracted to decrease blood flow and prevent formation of edema. Because the venoarteriolar reflex is activated by gravity, we tested the hypothesis that long-term weightlessness would attenuate it. The reduction in subcutaneous blood flow was measured by the 133Xe washout technique just proximal to the ankle joint in dependent lower legs of eight supine astronauts, where the knee joint was passively bent by 90°. The measurements were conducted before spaceflight and 3–6 h on landing following 4–6.5 mo in space. Activation of the venoarteriolar reflex reduced subcutaneous blood flow by 37 ± 9% ( P = 0.016) before flight and by 64 ± 8% ( P < 0.001) following landing with no statistical significant difference between the two reductions ( P = 0.062). Therefore, our results show that the venoarteriolar reflex is not attenuated by weightlessness and therefore does not need the everyday stimulus of gravity to maintain efficiency.
Time course of insulin sensitivity and skeletal muscle glycogen synthase activity after a single bout of exercise in horses
Authors: Pratt Shannon E. , Geor Raymond J. , Spriet Lawrence L. , McCutcheon L. Jill
Published: June 2007

The time course of insulin sensitivity, skeletal muscle glycogen and GLUT4 content, and glycogen synthase (GS) activity after a single bout of intense exercise was examined in eight horses. On separate days, a euglycemic-hyperinsulinemic clamp (EHC) was undertaken at 0.5, 4, or 24 h after exercise or after 48 h of rest [control (Con)]. There was no increase in mean glucose infusion rate (GIR) with exercise (0.5-, 4-, and 24-h trials), and GIR was significantly decreased at 0.5 h postexercise (GIR: 8.6 ± 2.7, 6.7 ± 2.0, 9.0 ± 2.0, and 10.6 ± 2.2 mg·kg−1·min−1for Con and at 0.5, 4, and 24 h, respectively). Before each EHC, muscle glycogen content (mmol glucosyl units/kg dry muscle) was higher ( P < 0.05) for Con (565 ± 102) than for other treatments (317 ± 84, 362 ± 79, and 382 ± 74 for 0.5, 4, and 24 h, respectively) and muscle GLUT4 content was unchanged. Pre-EHC active-to-total GS activity ratio was higher ( P < 0.05) at 0.5, 4, and 24 h after exercise than in Con. Post-EHC active GS and GS activity ratio were higher ( P < 0.05) in Con and at 24 h. There was a significant inverse correlation ( r = −0.43, P = 0.02) between glycogen content and GS activity ratio but no relationship between GS activity and GIR. The lack of increase in insulin sensitivity, determined by EHC, after exercise that resulted in a significant reduction in muscle glycogen content is consistent with the slow rate of muscle glycogen resynthesis observed in equine studies.