bluuebunny/crossref_metadata_2025 huggingface dataset:
MULTIPLICITY DISTRIBUTIONS OF TARGET FRAGMENTS IN 60 AGeV16O-EMULSION INTERACTIONS
Authors: EL-NADI M. , METTWALLI N. , SHAAT E.A. , HUSSIEN A. , ABOU-MOUSSA Z. , KAMEL S. , EL-WAHID F. ADB , ELLEITHY M.A.
Published: October 2004

The results of the interactions of 60 AGeV 16 O in nuclear emulsion are studied and compared with those previously obtained for the same projectile at different energies where it was found that within the energy range from 2.1 up to 200 AGeV, the probability for central collisions of 16 O with emulsion nuclei as well as the percentage of events having projectile fragments (PFs) of charge Z≥3 are nearly constant.

Multiplicity distributions of different charged secondaries are compared with the predictions of the Monte Carlo Code VENUS which takes into account the intranuclear cascading. The correlations between the various parameters are discussed. The data on shower and grey produced particles are well described by VENUS, however the black track data show a significant departure from this model. The study of heavy track data confirms the limiting fragmentation behaviour in high energy collisions. The multiplicity distributions of different charged secondaries are also compared with those obtained using different projectiles at nearly the same energy.
COLOR SCREENING POTENTIAL AND DISSOLUTION OF HEAVY QUARKONIUM
Authors: YU-BING DONG
Published: October 2004

The binding and dissolution of heavy quarkonium are investigated with a temperature-dependent screening quark potential model. The results show that the color screening effect considered by lattice gauge calculation at temperature T=0 plays an important role on the determination of the critical screened mass of the high-lying excited state of heavy quarkonium.
INFLUENCE OF MATING TYPE AND SELECTION ON THE GENETIC INFORMATION FLOW
Authors: BARTOLONI N.
Published: October 2004

In this work a quantitative evaluation of the influence of mating type and selection on the genetic information flow in ecosystems is considered. Assuming the Schmalhausen’s model of information dynamics, a measure of information that accounts both, for the amount of genetic information in the population and the transformations induced by selection and mating type on the amount of information is employed. Furthermore, some measures of information transfer, channel noises and information loss are employed in the evaluation of two sexual reproductive types very relevant in plant populations: random mating and selfing. The measures employed arise from the Shannon’s General Theory of Communication. They are conditional entropies and the average mutual information. Reproduction takes place in the past generation after transformation of the genetic structure of the population through selection. In case of clastic selection an expression for the measure of fitness entropy is computed. Basic Mendelian rules of inheritance are assumed in the derivation of the one-generation transition probabilities. Finally, a numerical application is analyzed.
GLUTATHIONE DECAY IN STORED BLOOD MEASURED BY ELECTRON SPIN RESONANCE
Authors: GORONCY ALEXANDER K. , FARACH HORACIO A. , POOLE JR. CHARLES P. , GONZALEZ M. FRANCISCO , PAOLI TOMAS DE , HAGER ALFREDO
Published: October 2004

An electron spin resonance has been developed by our group which employs spin labeled erythrocytes to study the decay of glutathione in stored blood. The results are compared with determinations made by the usual optical method. The values of the glutathione concentration C(t) in the blood fit the stretched exponential equation. [Formula: see text] where C0 is the initial concentration, at time t=0, Cf is the final concentration at time t→∞, and the constants n and τ have the average values [Formula: see text] for the ESR and optical determinations. The reproducibility is better and the scatter of the data is much less for our recently developed ESR method.
STATIONARY RANK-SIZE RELATION FOR COMMUNITY OF LOGISTICALLY GROWING GROUPS
Authors: SENO HIROMI , MATSUMOTO HARUO
Published: October 2004

Rank-size relation derived from the size distribution for a number of growing groups is considered with a mathematical model described by a type of von Foerster equation. Size of each group grows in the logistic manner with the common intrinsic growth rate and carrying capacity. New groups are produced from present groups with a reproduction rate, which depends on the size of the mother group. Each group undergoes the extinction probability which depends on the group size. We discuss how the characteristics of some typical rank-size relations of the community of groups depend on the dynamical factors governing the community. It is shown that the typical rank-size relation requires specific form of the size-dependence of extinction rate, and we discuss how the observed typical rank-size relation could really reflect the dynamical factor governing the community.
SIMULTANEOUS EFFECT OF TWO TOXICANTS ON BIOLOGICAL SPECIES: A MATHEMATICAL MODEL
Authors: SHUKLA J.B. , DUBEY B.
Published: October 2004

In this paper, a mathematical model to study the simultaneous effect of two toxicants (one is more toxic than the other) on the growth and survival of a biological species is proposed. The cases of instantaneous spill, constant and periodic emissions of each of the toxicant into the environment are considered. It is shown that in the case of an instantaneous spill of each of the toxicant into the environment, the species after its initial decrease in density may recover to its original level after a period of time, the magnitude of which depends on the toxicity and washout rate of each of the toxicant. However, if both the toxicants are emitted with constant rates, the species in the habitat is doomed to extinction sooner than the case of a single toxicant having the same influx and washout rates as one of them, the extinction rate becoming faster with the increase in toxicity and emission rate of the other toxicant. It is also shown that for a small amplitude periodic emission of the toxicant with a constant mean, the stability behavior of the system is same as that of the case of the constant emission. It is found further through the model study that if suitable efforts are made to reduce the emission rate of each of the toxicant at the source and its concentration in the environment by some removal mechanism, an appropriate level of species density can be maintained.
THEORETICAL CARDIOLOGY: FROM MATHEMATICAL TO QUALITATIVE MODELS
Authors: SIREGAR P.
Published: October 2004

A central concern in simulation studies is the adequation, or inadequation, of a designed model with respect to its intended goal. Models of cardiac electrical activity may differ in complexity, level of description and representation. Depending on the events to be be simulated, analytical, cellular automatas and qualitative models can be used. Their advantages and shortcomings can be put forth by comparing the space and time complexities, and if factors clinically relevant for studying arrhythmias and ischemias are taken into account in the respective models. In this paper, the factors under scrutiny are those characterizing impulse formation and conduction. If and how they are represented and computed constitutes a means of comparison between the models. The simplifying assumptions built into each can thus be put forth. Through illustrative examples, we then show that qualitative models can assume the explanatory and a predictive role usually devolved to numerical models. Such models can be used as a primer to quantification in a multi-stage process. A possibly useful development would be to integrate the analytical, cellular and qualitative models within a single computational framework. Central to this task is qualification. All piece of knowledge that is implicit in the mathematical or procedural representations has to be made explicit. Semantic links can thereafter be established between the models. This knowledge could be the starting point of a system emulating the reasoning of a theoretician working at different levels of detail. Its role would be to help researchers select, instantiate and interpret results of their most detailed cellular automata and/or analytical models.
NON-EQUILIBRIUM THERMODYNAMICS AND STOCHASTICS OF GOMPERTZIAN GROWTH
Authors: CHAKRABARTI C.G. , BHADRA SYAMALI
Published: October 2004

The paper deals with the non-equilibrium thermodynamic modelling of Gompertzian growth of a population substantiated by a stochastic model of the system under random disturbance of the environment.
EFFECT OF CROSS-DIFFUSION ON A DIFFUSIVE PREY-PREDATOR SYSTEM—A NONLINEAR ANALYSIS
Authors: CHATTOPADHYAY J. , SARKAR A.K. , TAPASWI P.K.
Published: October 2004

In this paper, we show that a simple prey-predator diffusive system may give rise to spontaneous emergence of dissipative structure (patchiness) only in the presence of cross-diffusion. The critical wave-length just sufficient to drive the system to local instability has been worked out. Moreover, by constructing a suitable Liapunov function, we have also investigated the global behaviour of the dissipative structure.
3-D CARDIAC MODELING: A COMPUTER VISION APPROACH IN SPATIO-TEMPORAL IMAGE SEQUENCES
Authors: COATRIEUX J.L. , TOUMOULIN C. , COLLOREC R.
Published: October 2004

A very active research was conducted on motion analysis. Most of the concepts, methods and assumptions are well established and lead to additional improvements in computer vision applications. Even in medicine where we have to deal with noisy data, low contrast structures and deformable objects, they bring new cues at all the processing stages. This paper emphasizes the specificities of this area and also the potential difficulties. A compilation of results is given aimed at the quantification of heart kinetics in Digital Subtraction Angiography (DSA). They illustrate the benefits of cooperative schemes such as motion based segmentation, moving object identification, three-dimensional reconstruction and interpretation.
CAN A FALLIBLE TIT-FOR-TAT STRATEGY MAINTAIN COOPERATION IN A POPULATION OTHERWISE COMPOSED OF NON-CONDITIONAL STRATEGISTS?
Authors: GERARD J.F. , QUENETTE P.Y. , LOISEL P. , CHALMEAU R.
Published: October 2004

Contrary to what often seems to be accepted, 100% Tit-for-Tat is not an ESS, even in the three-pure-strategy game Tit-for-Tat-Always Cooperate-Always Defect, for which 100% Always Defect finally remains the only attractor for the composition of “asexual” populations. The present paper firstly investigates the dynamics of the Tit-for-Tat-Always Cooperate-Always Defect game for asexual populations, with the more realistic assumption that Tit-for-Tat sometimes fails to apply its algorithm. Surprisingly, this perturbation of the original game leads to different attractor patterns, in relation to the numerical values of the expected number of meetings and of Tit-for-Tat’s failure rate. These patterns generally include one punctual attractor for which most dyads at least partially cooperate. Nevertheless, the attractor alternative to 100% Always Defect in each pattern may become unstable when certain mixed strategies (cooperating and defecting at random) are introduced into the game, and the whole flow of strategy frequencies may then converge towards 100% Always Defect. Beyond the reiterated Prisoner’s Dilemma, the present analysis illustrates how self-organizing processes at infra-populational levels, like that occurring in dyads including at least one fallible Tit-for-Tat, can influence the evolution of populations.
THE ROLE OF RAPID DIFFUSION IN A SIMPLE FOOD CHAIN
Authors: MUKHERJEE DEBASIS
Published: October 2004

This paper deals with the stabilizing effect of diffusion on a four species food chain model. Conditions for local stability and instability of the model without diffusion are derived in terms of the threshold value of the functional responses of the predators at the steady state. It is also shown that an unstable equilibrium of the food chain without diffusion can be made stable for the model with diffusion, provided diffusion coefficients and predator functional responses satisfy certain threshold properties at the steady state. Lastly conditions for global stability of the model with diffusion are derived.
STRESSES AND STRAINS IN THE LEFT VENTRICULAR WALL APPROXIMATED AS A THICK CONICAL SHELL USING LARGE DEFORMATION THEORY
Authors: CHAUDHRY H.R. , BUKIET B. , DAVIS A.M. , FINDLEY T.
Published: October 2004

In this paper, stress and strain equations are developed for the left ventricle mainly to find the influence of the ventricle’s shape on wall stresses. Here, the ventricle is assumed to be a thick-walled truncated conical shell and large elastic deformation theory is applied. Our model is compared to corresponding results approximating the left ventricle as a spherical shell. Clinically relevant parameters such as the myocardial stiffness constant, the stretch ratios and the stresses and strains have been computed using available canine data. The conical model leads to more realistic results than the spherical model and enables one to evaluate stresses and strains from base to apex instead of only at the equatorial region as in a cylindrical model.
GLOBAL RATIO OF EFFICIENCY IN A SINGLE CHAIN BINARY MIXTURE
Authors: MOVILEANU LIVIU , POPESCU DUMITRU
Published: October 2004

This paper is devoted to a newly proposed subject regarding the association processes from a single chain binary mixture. A test system was developed for 36 binary mixtures to evaluate the mean association probabilities. A methylene group added to the short hydrophobic chain is four times more effective on the mean self-association probability h11 than a methylene group added to the long hydrophobic chain. As far as this comparing effect is concerned, this is twice more effective for the mean self-association probability h22.
NEURAL NETWORK MODELS TO PREDICT PENETRATION OF WILD BOAR INTO CULTIVATED FIELDS
Authors: SPITZ F. , LEK S. , DIMOPOULOS I.
Published: October 2004

Wildlife managers need to evaluate the regional risk of damage by big game in any cultivated plot. Nevertheless, such an evaluation can be biased by nonlinearity, a common difficulty when facing ecological problems. We propose a model for the impact of wild boars on cultivated fields, based on artificial neural networks, with a backpropagation algorithm. The first model, predicting the frequency of impact on a particular plot, gives a good determination coefficient (R2=0.91). The second model, predicting the presence or absence of impact during a particular week, gives over 80 % correct results.
ELEMENTS OF MATHEMATICAL MODELING OF EVOLUTION IN NUMBER OF A SOLE POPULATION
Authors: ARINO O. , KOUTSIKOPOULOS C. , RAMZI A.
Published: October 2004

A spatio-temporal model of the dynamics of a population of soles is presented. The model includes three phases of the life cycle of this species of fishes, starting from the pelagic phase to the adult phase through a recruitment to be in the juvenile phase, depending on the climatic conditions. It also takes into account the migration processes, for larvae towards nurseries, and for adults towards the spawning areas. We used the model to provide an estimate of the probability of arrival of the larvae to the nurseries under the interaction of diffusion and climatic processes.
A COMPARTMENTAL MODEL OF SLEEPING SICKNESS IN CENTRAL AFRICA
Authors: ARTZROUNI MARC , GOUTEUX JEAN-PAUL
Published: October 2004

We present a five-variable compartmental model for the spread of Trypanosoma brucei gambiense, the parasite responsible for the transmission (through tsetse flies) of sleeping sickness in Central Africa. The model’s equilibrium points depend on two “summary parameters”: gr, the proportion removed among human infectives, and R0, the basic reproduction rate. Stability results are obtained for the origin but not for other equilibrium points. A two-variable simplified version of the model is presented and the stability of all its equilibrium points can be investigated analytically. Both models are applied to the Niari focus of Central Africa and used to test the impact of a vector control strategy. The models’ results are in agreement with the extinction of the epidemic that was brought about by a fifty percent decrease in vector density.
A MODEL OF AN ADAPTIVE RECEPTOR BASED ON THE RETINA
Authors: BOUSSARD ERIC , PAKDAMAN KHASHAYAR , BEDFER GILLES , VIBERT JEAN-FRANÇOIS
Published: October 2004

A model of the retina based on biological data is developed to study the processing of images by the retina as a model for an adaptive receptor. The direct visual pathway (photoreceptors, bipolar and ganglion cells) and the horizontal units and their gap-junctions, as well as the dopaminergic interplexiform cells and dopamine release are modeled. A small network of 12 units is first simulated in order to study the behavior of the different components involved, and the role played by lateral inhibition is analyzed. A 64×64 photoreceptors model, containing 16,448 units, is then simulated. The following properties were found for stimuli that remain constant in time: (i) The difference between the time constants of the photoreceptors and the horizontal units lead to both the formation of a transient output image that contains pertinent features of the input, and the formation of a reverse after-image when the stimulus is removed. (ii) Global modifications of lateral inhibition strength allow either contrast rendering or contour enhancement. Local modifications of lateral inhibition strength bring about adaptation to local input characteristics.
STRESSES AND STRAINS IN THE PASSIVE LEFT VENTRICLE
Authors: CHAUDHRY H.R. , BUKIET B. , FINDLEY T. , RITTER A.B.
Published: October 2004

In this paper, we estimate the stresses and strains from the equatorial region down to the apex of the heart by modeling the passive left ventricle as a frustrum of a thick hollow cone. Large deformation theory has been employed in this analysis. Furthermore, the effects of residual stresses and the anisotropy due to muscle fiber orientation have been included. It is observed that circumferential stress, which is the most important physiologically, decreases considerably at the endocardium and is more evenly distributed through the wall when residual stresses are taken into account. The stresses also decrease as we go from the equatorial region to the apex. Because heart muscles physically have residual stresses, the consequent lower stress gradient through the wall enhances the diastolic function of the left ventricle.
DECISION MAKING WITH BELIEF STRUCTURES: AN APPLICATION IN RISK MANAGEMENT
Authors: ENGEMANN KURT J. , MILLER HOLMES E. , YAGER RONALD R.
Published: October 2004

This paper examines the problem of selecting an alternative in situations in which there exists uncertainty in our knowledge of the state of the world. We show how the ordered weighted averaging aggregation operators provide a unifying approach to selecting alternatives under uncertainty. In particular, we see how these operators provide a type of probability associated with our degree of optimism. We also show how the Dempster-Shafer belief structure provides a general framework for representing the information a decision maker has regarding relevant events. We then propose a methodology for decision making under uncertainty, integrating the ordered weighted averaging aggregation operators and the Dempster-Shafer belief structure. The proposed methodology is applied to a real world case involving risk management at one of the nation’s largest banks.
MODELING FUZZY REASONING USING HIGH LEVEL FUZZY PETRI NETS
Authors: SCARPELLI HELOISA , GOMIDE FERNANDO , PEDRYCZ WITOLD
Published: October 2004

A formal tool, the High Level Fuzzy Petri Net, is proposed for representing and processing fuzzy production rules in a knowledge base. The basic net structures to model inference patterns in approximate reasoning are introduced. The chaining mechanism used and the modeling of rules with fuzzy quantifiers and certainty factors are discussed. We have also investigated the representation of parallel and conflicting rules. Two types of fuzzy reasoning algorithms, to answer data driven and goal driven queries are described. The issue of time complexity of the algorithms is also addressed.
URYSOHN-CLOSEDNESS ON FUZZY LATTICES
Authors: CHEN SHUI-LI
Published: October 2004

In this paper the concepts of Urysohn-convergence of filters and Urysohn-closedness on fuzzy lattices are introduced. Some important results with respect to fuzzy lattices are obtained.
CHARACTERIZATION OF COHERENT CONDITIONAL PROBABILITIES AS A TOOL FOR THEIR ASSESSMENT AND EXTENSION
Authors: COLETTI GIULIANELLA , SCOZZAFAVA ROMANO
Published: October 2004

A major purpose of this paper is to show the broad import and applicability of the theory of probability as proposed by de Finetti, which differs radically from the usual one (based on a measure-theoretic framework). In particular, with reference to a coherent conditional probability, we prove a characterization theorem, which provides also a useful algorithm for checking coherence of a given assessment. Moreover it allows to deepen and generalise in useful directions de Finetti’s extension theorem (dubbed as “the fundamental theorem of probability”), emphasising its operational aspects in many significant applications.
ON THE RELATIONSHIP OF ASSOCIATIVE COMPENSATORY OPERATORS TO TRIANGULAR NORMS AND CONORMS
Authors: KLEMENT ERICH PETER , MESIAR RADKO , PAP ENDRE
Published: October 2004

When using a t-norm for combining fuzzy sets, no compensation between small and large degrees of membership takes place. On the other hand, a t-conorm provides full compensation. Since many real situations do not fall into either one category, so-called compensatory operators have been proposed in the literature [H.-J. Zimmermann and P. Zysno, Fuzzy Sets and Systems4 (1980) 37–51] which are non-associative in nature. In this paper, associative compensatory operators (whose domain is the unit square with the exception of the two points (0, 1) and (1, 0) and whose only associative extensions to the whole unit square are the aggregative operators suggested in [J. Dombi, Europ. J. Oper. Res.10 (1982) 282–293]) are studied and their representation in terms of multiplicative generators is given. It is shown that these operators are constructed with the help of strict t-norms and t-conorms, in a way which is similar to ordinal sums. Finally, the duals of such operators are shown to be again associative compensatory operators, and a characterization of self-dual operators is given.
ORDERINGS FOR CLASSES OF AGGREGATION OPERATORS
Authors: BASILE L. , D’APUZZO L.
Published: October 2004

Some procedures for synthesizing values of judgements in multicriteria decision making have been provided by several authors. The functionals of synthesis they consider are frequently means. The most general form of these operators involves both a weighting function w and a continuous and strictly monotonic function φ. Our aim is to analyze the behaviour of the aggregation operator Fωφ depending on w and φ. To this purpose we introduce a pre-ordering relation on the set W of weighting functions and on the set Φ of continuous and strictly monotonic functions, which allows us to compare the synthesizing functionals.
MULTI-PERIOD RISK MANAGEMENT USING FUZZY LOGIC
Authors: RUBINSON TERESA
Published: October 2004

In this paper, we present a fuzzy dynamic programming procedure for long term risk management. This approach is designed to provide insights on trade-offs between potential risks and rewards, the dynamics of interacting economic factors, and the feasibility of corporate goals over a long term planning horizon. This approach is applicable to many long term planning problems involving selection from a number of alternatives, when the decision parameters are imprecise and absolute requirements and decision thresholds can not be specified. A few examples of problems of this type include: portfolio optimization, risk management, evaluation of securities, liquidity management, and asset/liability management (which is given particular emphasis in this paper). Our formulation provides a computationally efficient and natural representation of the decision trade-offs inherent in many long term money management problems. This, in turn, facilitates the exploration and analysis of many alternative investment strategies under many possible future scenarios.
EXPLICIT FUNCTIONS OF FUZZY CONTROL SYSTEMS
Authors: KÓCZY LÁSZLÓ T. , SUGENO MICHIO
Published: October 2004

Fuzzy control systems have proved their applicability in many areas. Their user-friend-liness and transparency certainly belong to their main advantages, and these two enable developing and tuning such controllers easily, without knowing their exact mathematical description. Nevertheless, it is of interest to know, what mathematical functions hide behind a set of fuzzy rules and an inference machine. For practical purposes it is necessary to consider real, implementable fuzzy control systems with reasonably low computational complexity. This paper discusses the problem of what types of functions are generated by realistic fuzzy control systems. In the paper the explicit formulae of the transference functions for practically important special cases are determined, controllers having rules with triangular and trapezoidal membership functions, and crisp consequents. Here we restrict our investigations to rules with a single input.
ON FUZZINESS AND DUALITY IN FUZZY DIFFERENTIAL EQUATIONS
Authors: KANDEL ABRAHAM , FRIEDMAN MENAHEM , MING MA
Published: October 2004

In this work we define a conjugate fuzzy Cauchy problem and discuss the major differences between an ordinary and a conjugate fuzzy Cauchy problems. A necessary condition for the existence of a fuzzy solution to the conjugate fuzzy Cauchy problem is proposed.
INTERVAL METHODS IN KNOWLEDGE REPRESENTATION
Authors: Kreinovich Vladik
Published: October 2004

In this issues, we continue to publish abstracts and reviews of recents papers on interval methods in knowledge representation. In knowledge representation, intervals are used for two main purposes:

• to describe durations of events; and

• to describe uncertainty of measurement results and expert estimates of different quantities; often, we do not know the exact value of a quantity, but we know its lower and upper bounds (e.g., we may not know the exact value of someone's weight, but we may know that this weight is in between 140 and 160 pounds).

An important case of this uncertainty occurs in knowledge elicitation, when we ask experts to numerically estimate their degrees of belief in their own statements; in this case, it is often difficult for an expert to estimate this degree of belief precisely, but an expert can often provide us with an interval of possible values.

The reviews are collected by Vladik Kreinovich, Department of Computer Science, University of Texas at El Paso, El Paso, TX 79968, USA, email vladik@cs.utep.edu
The female intestine is more resistant than the male intestine to gut injury and inflammation when subjected to conditions associated with shock states
Authors: Homma Hiroshi , Hoy Erik , Xu Da-Zhong , Lu Qi , Feinman Rena , Deitch Edwin A.
Published: October 2004

Having documented that proestrus female rats are more resistant to shock-induced acute gut and hence lung injury than male rats, we tested the hypothesis that the female gut is more resistant to injury and produces less of an inflammatory response than the male gut when exposed to conditions associated with shock states (hypoxia and acidosis) utilizing the ex vivo Ussing chamber system. Ileal mucosal membranes harvested from normal male and female rats mounted in Ussing chamber systems were exposed to normoxia or 40 min of hypoxia at a normal pH (pH 7.3) or acidosis (pH 6.8). Cytokine and nitric oxide levels in the serosal compartment of the Ussing chamber were measured at the end of the 3-h experimental period to assess the immunoinflammatory response, whereas FITC-dextran (mol wt 4,300) was employed to assess barrier function. Histomorphological changes were used to quantitate gut mucosal injury. Hypoxia, acidosis, or hypoxia plus acidosis was associated with a significant increase in proinflammatory cytokine production [interleukin (IL)-6, tumor necrosis factor, and macrophage inflammatory protein (MIP)-2] by the male compared with the female intestinal segments. In contrast, the female gut manifested a higher anti-inflammatory response (nitric oxide and IL-10) and improved intestinal barrier function as well as less evidence of mucosal injury than the male intestinal segments. Administration of estradiol or the testosterone receptor antagonist, flutamide, to male rats abrogated the increase in gut injury and the increased IL-6 and MIP-2 response observed after hypoxia plus acidosis. These results suggest that gender differences in the ex vivo intestinal response to stresses, such as hypoxia and acidosis, exist and that the administration of estradiol or blockade of the testosterone receptor to male rats mitigates these gender differences.
fMLP-stimulated neutrophils increase endothelial [Ca2+]iand microvessel permeability in the absence of adhesion: role of reactive oxygen species
Authors: Zhu Longkun , Castranova Vince , He Pingnian
Published: October 2004

Our previous study demonstrated that firm attachment of leukocytes to microvessel walls does not necessarily increase microvessel permeability ( Am J Physiol Heart Circ Physiol 283: H2420–H2430, 2002). To further understand the mechanisms of the permeability increase associated with leukocyte accumulation during acute inflammation, we investigated the direct relation of reactive oxygen species (ROS) release during neutrophil respiratory burst to changes in microvessel permeability and endothelial intracellular Ca2+concentration ([Ca2+]i) in intact microvessels. ROS release from activated neutrophils was quantified by measuring changes in chemiluminescence. When isolated rat neutrophils (2 × 106/ml) were exposed to formyl-Met-Leu-Phe-OH (fMLP, 10 μM), chemiluminescence transiently increased from 1.2 ± 0.2 × 104to a peak value of 6.7 ± 1.0 × 104cpm/min ( n = 12). Correlatively, perfusing individual microvessels with fMLP-stimulated neutrophils in suspension (2 × 107/ml) increased hydraulic conductivity ( Lp) to 3.7 ± 0.4 times the control value ( n = 5) and increased endothelial [Ca2+]ifrom 84 ± 7 nM to a mean peak value of 170 ± 7 nM. In contrast, perfusing vessels with fMLP alone did not affect basal Lp. Application of antioxidant agents, superoxide dismutase, vitamin C, or an iron chelator, deferoxamine mesylate, attenuated ROS release in fMLP-stimulated neutrophils and abolished increases in Lp. These results indicate that release of ROS from fMLP-stimulated neutrophils increases microvessel permeability and endothelial [Ca2+]iindependently from leukocyte adhesion and the migration process.
Ligand-mediated decrease of thyroid hormone receptor-α1in cardiomyocytes by proteosome-dependent degradation and altered mRNA stability
Authors: Kenessey Agnes , Ojamaa Kaie
Published: October 2004

Tri-iodo-l-thyronine (T3) is essential for maintaining normal cardiac contractile function by regulating transcription of numerous T3-responsive genes. Both hormone availability and relative amounts of nuclear thyroid hormone receptor isoforms (TRα1, TRβ1) determine T3effectiveness. Cultured neonatal rat ventricular myocytes grown in T3-depleted medium expressed predominantly TRα1 protein, but within 4 h of T3treatment, TRβ1 protein increased significantly, whereas TRα1 was decreased by 46 ± 5%. Using replication-defective adenoviruses to overexpress TRα1 in cardiomyocytes, we studied the mechanisms by which T3mediated the decrease in TRα1 protein. Inhibitors of the proteosome pathway resulted in an accumulation of ubiquitylated TRα1 in the nucleus and prevented T3-induced degradation of ubiquitylated TRα1, suggesting that T3induced proteosome-mediated degradation of TRα1; however, TR ubiquitylation was T3independent. TRα1 transcriptional activity, measured using transient transfection of a thyroid hormone-responsive element (TRE) reporter plasmid, was T3dose dependent and inversely proportional to nuclear TRα1 content, with 10 nM T3having maximum effect. Quantitative RT-PCR showed that both endogenous and adenovirus-expressed TRα1 mRNAs were significantly decreased to 54 ± 11 and 25 ± 5%, respectively, within 4 h of T3treatment. Measurements of TRα1 mRNA half-life in actinomycin D-treated cardiomyocytes showed that T3treatment significantly decreased TRα1 mRNA half-life from 4 h to less than 2 h, whereas it had no effect of TRβ1 mRNA half-life. These data support a role for both the proteosome degradation pathway and altered mRNA stability in T3-induced decrease of nuclear TRα1 in the cardiomyocyte and provide novel cellular targets for therapeutic development.
Dose-dependent effects of l-carnosine on the renal sympathetic nerve and blood pressure in urethane-anesthetized rats
Authors: Tanida Mamoru , Niijima Akira , Fukuda Yutaka , Sawai Hajime , Tsuruoka Nobuo , Shen Jiao , Yamada Shigeru , Kiso Yoshinobu , Nagai Katsuya
Published: October 2004

The physiological function of l-carnosine (β-alanyl-l-histidine) synthesized in mammalian muscles has been unclear. Previously, we observed that intravenous (IV) injection of l-carnosine suppressed renal sympathetic nerve activity (RSNA) in urethane-anesthetized rats, and l-carnosine administered via the diet inhibited the elevation of blood pressure (BP) in deoxycorticosterone acetate salt hypertensive rats. To identify the mechanism, we examined effects of IV or intralateral cerebral ventricular (LCV) injection of various doses of l-carnosine on RSNA and BP in urethane-anesthetized rats. Lower doses (1 μg IV; 0.01 μg LCV) of l-carnosine significantly suppressed RSNA and BP, whereas higher doses (100 μg IV; 10 μg LCV) elevated RSNA and BP. Furthermore, we examined effects of antagonists of histaminergic (H1 and H3) receptors on l-carnosine-induced effects. When peripherally and centrally given, thioperamide, an H3 receptor antagonist, blocked RSNA and BP decreases induced by the lower doses of peripheral l-carnosine, whereas diphenhydramine, an H1 receptor antagonist, inhibited increases induced by the higher doses of peripheral l-carnosine. Moreover, bilateral lesions of the hypothalamic suprachiasmatic nucleus eliminated both effects on RSNA and BP induced by the lower (1 μg) and higher (100 μg) doses of peripheral l-carnosine. These findings suggest that low-dose l-carnosine suppresses and high-dose l-carnosine stimulates RSNA and BP, that the suprachiasmatic nucleus and histaminergic nerve are involved in the activities, and that l-carnosine acts in the brain and possibly other organs.
Aetiological Factors in Paediatric Urolithiasis
Authors: van’t Hoff William G.
Published: October 2004

The aetiology of stones in children differs from that in adults. Young children, especially boys, are prone to infective stones, although this type of calculi is decreasing in frequency over time in prosperous countries. Two monogenic causes, cystinuria and hyperoxaluria, each account for 5–15% of paediatric stones. Increased factors for stone formation in children include prematurity, neurological problems, ketogenic diet and reconstructed or augmented bladders. Hypercalciuria is commonly found in paediatric stone formers, is usually idiopathic and is only rarely associated with hypercalcaemia. All children with stones should undergo a metabolic evaluation.
Medical Management of Urinary Stone Disease
Authors: Pak Charles Y.C.
Published: October 2004

A variety of dietary and metabolic factors may contribute or cause stone formation in idiopathic calcium oxalate nephrolithiasis. Dietary factors include a high intake of animal proteins, oxalate and sodium, and a low intake of fluids and potassium-containing citrus products. Some of the metabolic causes of stones are hypercalciuria, hypocitraturia, gouty diathesis, hyperoxaluria, and hyperuricosuria. Dietary modification, to be applied in all patients with stones includes a high fluid intake, restriction of oxalate and sodium, and balanced diet with animal proteins complemented by adequate intake of fruits and vegetables. When dietary modification is ineffective in controlling stone formation or in the presence of severe metabolic derangements, a pharmacologic intervention may be necessary. In a simple approach, thiazide or indapamide with potassium citrate is recommended for patients with hypercalciuria, and potassium citrate alone for the remaining normocalciuric subjects.
An Overview of Divalent Cation and Citrate Handling by the Kidney
Authors: Unwin R.J. , Capasso G. , Shirley D.G.
Published: October 2004

Urinary calcium, magnesium and citrate levels are important in promoting or inhibiting renal stone formation. Here we review current information on the tubular handling of these ions. Most filtered calcium is reabsorbed in the proximal tubule and the thick ascending limb (TAL) of the loop of Henle, largely paracellularly; most of the remainder is reabsorbed in the distal tubule, transcellularly. Calcium reabsorption in the TAL and distal tubule is stimulated by parathyroid hormone and vitamin D; other factors influencing its renal handling include extracellular volume status and acid-base balance. Little filtered magnesium is reabsorbed in the proximal tubule; the bulk is reabsorbed paracellularly in the TAL, while most of the remainder is reabsorbed transcellularly in the distal tubule. Dietary intake, peptide hormones and chronic potassium depletion can all influence magnesium reabsorption in the TAL and distal tubule. Most filtered citrate is taken up across the apical membrane of the proximal tubule via a sodium-dicarboxylate co-transporter (NaDC-1). It also enters proximal tubular cells across the basolateral membrane; citrate contributes to the cells’ oxidative metabolism. Citrate excretion is affected by acid-base balance, acetazolamide treatment, chronic potassium depletion and urinary excretion of calcium and magnesium. Where possible, we have indicated the mechanisms of these complex interactions.
Clinical Value of Crystalluria and Quantitative Morphoconstitutional Analysis of Urinary Calculi
Authors: Daudon Michel , Jungers Paul
Published: October 2004

Morphoconstitutional analysis of urinary calculi, i.e. morphologic examination combined with Fourier transform infrared spectroscopy (FTIR), is of decisive interest for the diagnosis of rare but severe inherited or acquired stone diseases such as cystine, 2,8-dihydroxyadenine, xanthine, struvite, ammonium urate or drug-containing calculi as well as primary hyperoxalurias. In the absence of early diagnosis and proper management, these diseases may lead to progressive loss of renal function. Among common forms of calcium oxalate (CaOx) stones, predominant CaOx monohydrate (whewellite) is mainly associated with hyperoxaluric conditions whereas predominant CaOx dihydrate (weddellite) is mainly associated with hypercalciuria, and this distinction is of interest to orient metabolic evaluation and preventive measures. Crystalluria examination, also based on morphology and FTIR, is a valuable diagnostic method when no stone is available for analysis. Presence of specific crystals (cystine, 2,8-dihydroxyadenine, struvite, ammonium urate) is diagnostic by itself. In all types of nephrolithiasis, serial crystalluria determination appears as a simple, cheap and reliable method to evaluate the risk of stone formation and assess the effectiveness of preventive measures. Determination of urinary crystal volume was in our experience a useful tool in the management of patients with cystinuria or primary hyperoxaluria in the post-transplantation period. In conclusion, both accurate morphologic and FTIR analysis of stones and serial crystalluria determination should be more largely used, in view of their value in the diagnosis and management of renal stone formers.
Osteopontin and Calcium Stone Formation
Authors: Kleinman Jack G. , Wesson Jeffrey A. , Hughes Jeremy
Published: October 2004

Osteopontin (OPN) is a phosphorylated protein of wide tissue distribution that is found in association with dystrophic calcification including in the organic matrix of kidney stones. It is a strong inhibitor of crystal formation and growth in vitro, but there is still debate regarding its effects upon crystal adhesion to tubular epithelial cells. In this brief review, we will outline the evidence implicating OPN in stone disease with the primary emphasis being on the interaction of OPN with calcium oxalate (CaOx), the major constituent of calcium containing stones. Finally, preliminary data is presented regarding the amounts and features of OPN present in the urine of stone formers and normal individuals.
Role of Nutrition in the Formation of Calcium-Containing Kidney Stones
Authors: Taylor Eric N. , Curhan Gary C.
Published: October 2004

Diet plays an important role in the pathogenesis of calcium-containing kidney stones. Although much work has demonstrated that specific dietary components alter urinary composition and supersaturation, relatively few studies link the ingestion of these components with actual nephrolithiasis. This article reviews the dietary factors thought to promote or inhibit the formation of calcium stones and discusses the current controversies in the field of nutrition and nephrolithiasis. Special attention is paid to the roles of dietary calcium, supplemental calcium, oxalate, phytate, and n–3 fatty acids. We offer dietary recommendations to individuals who have suffered from a calcium-containing kidney stone, and emphasize that a patient’s 24-hour urine chemistries should be used to help guide dietary intervention.
Reduced Glycosaminoglycan Sulfation Diminishes the Agrin Signal Transduction Pathway
Authors: McDonnell Kelly M.W. , Grow Wade A.
Published: October 2004

Proteoglycans consist of a protein core complexed to glycosaminoglycan (GAG) side chains, are abundant in skeletal muscle cell membranes and basal lamina, and have important functions in neuromuscular synapse development. Treatment with chlorate results in the undersulfation of heparan sulfate and chondroitin sulfate GAGs in cell culture. In addition, chlorate treatment decreases the frequency of spontaneous acetylcholine receptor (AChR) clustering in skeletal muscle cell culture. AChRs and other molecules cluster to form the postsynaptic component of neuromuscular synapses. Chlorate treatment is shown here to decrease the frequency of agrin-induced AChR clustering and agrin-induced tyrosine phosphorylation of the AChR β-subunit. These data suggest that reduced GAG chain sulfation decreases the frequency of AChR clustering by diminishing the agrin signal transduction pathway.
The Role of Glucose in Brain Injury Following the Combination of Lipopolysaccharide or Lipoteichoic Acid and Hypoxia-Ischemia in Neonatal Rats
Authors: Eklind Saskia , Arvidsson Pernilla , Hagberg Henrik , Mallard Carina
Published: October 2004

We have previously shown that lipopolysaccharide (LPS) sensitizes the immature rat brain to subsequent hypoxic-ischemic (HI) injury; however, the underlying mechanisms remain unclear. In this study, we examined the role of glucose in the sensitizing effects of LPS and lipoteichoic acid (LTA) in combination with HI in 7-day-old rats. LPS/HI resulted in hypoglycemia which lasted 24 h and lactate levels were increased from 6 to 10 h after LPS administration. LPS/HI induced severe brain injury, which persisted 2 weeks after LPS/HI. Administration of glucose to LPS-treated animals with HI reduced brain injury in the cerebral cortex and hippocampus, while striatal damage remained. LTA/HI did not affect blood glucose, lactate or brain injury. In conclusion, enhanced blood glucose levels during HI after LPS administration conferred protection in some brain regions but not in the striatum, suggesting that alterations in glucose can only partly explain the sensitizing effect of LPS.
Mitigation of Meconium-Induced Lung Injury by Surfactant and Inhaled Nitric Oxide Is Associated with Suppression of Nuclear Transcription Factor Kappa B
Authors: Hu Xiaowei , Cao Lei , Lam Li Kuei , Zhu Liewei , Guo Chunbao , Sun Bo
Published: October 2004

Objective: To investigate whether the mechanism of a combined surfactant and inhaled nitric oxide (iNO) in improvement of oxygenation and mitigation of lung injury is associated with suppression of nuclear transcription factor kappa B (NF-ĸB) in the lung tissue of ventilated rabbits with meconium aspiration. Methods: Adult rabbits (weight 2.0–3.5 kg, n = 33) were anesthetized, intratracheally received human meconium, and were subjected to pressure support ventilation for 30–60 min to induce hypoxemic respiratory failure and lung injury. They were then treated for 6 h in groups: control animals; rabbits receiving iNO; animals receiving surfactant (100 mg/kg), and rabbits receiving both iNO and surfactant. iNO was delivered continuously by mass flow controller in sequence at 1, 10, 20, and 40 ppm each for 60 min at 30-min intervals. Results: Improvement in oxygenation and lung mechanics was found in the animals receiving both iNO and surfactant, associated with a marked response to iNO at 10 and 20 ppm (p < 0.05), a significantly higher ratio of disaturated phosphatidylcholine to total proteins, a lower surface tension of phospholipids from bronchoalveolar lavage fluid, a lower wet-to-dry lung weight ratio and lower lung injury scores, and better alveolar aeration. The iNO- and surfactant-treated groups had only transient or moderate-to-intermediate improvement in the associated parameters. The expression of NF-ĸB in lung tissue was enhanced in the control group, attenuated in the groups treated with either iNO or surfactant, and significantly suppressed in the group receiving both iNO and surfactant. Conclusion: Improvements of lung mechanics and gas exchange and mitigation of lung injury by the combined surfactant and iNO are related to suppression of NF-ĸB expression in lung tissue of ventilated rabbits with hypoxemic respiratory failure.
Benchmarking a Test of Temporal Orientation with Data from American and Taiwanese Persons with Alzheimer’s Disease and American Normal Elderly
Authors: Tractenberg Rochelle E. , Weinstein Maxine , Weiner Myron F. , Aisen Paul S. , Fuh Jong-Ling , Goldman Noreen , Chuang Yi-Li
Published: October 2004

Orientation questions are readily incorporated into longitudinal population surveys, but their value as a screening tool for cognitive impairment is uncertain. We evaluated the screening value of four orientation-to-time items (TTO) from the Mini-Mental State Examination (MMSE) by determining their association with full-scale MMSE scores. Data collected under protocols with strict eligibility criteria in the US (64 normal elderly, 242 persons with probable Alzheimer’s disease) and Taiwan (241 persons with probable Alzheimer’s disease) were analyzed. The TTO and full-scale MMSE scores were significantly correlated (p < 0.05) in persons with a Clinical Dementia Rating (CDR) score of 0 or 1; this was not significant in persons with a CDR of >1 (p > 0.05). Both TTO and MMSE were significantly associated with education in persons with 0–7 years of education; some MMSE items, but none of the TTO items, were associated with education in persons with more than 7 years of education. TTO may be a useful component of cognitive screening efforts.