Showing papers by "University of Oviedo published in 2002"

Strategies for MMP inhibition in cancer: innovations for the post-trial era

Abstract: For more than two decades, the view that tumour-associated matrix metalloproteinases (MMPs) were required for peritumour tissue degradation and metastasis dominated the drive to develop MMP inhibitors as anticancer therapeutics. Until recently, clinical trials with MMP inhibitors have yielded disappointing results, highlighting the need for better insight into the mechanisms by which this growing family of multifunctional enzymes contribute to tumour growth. It is now recognized that MMP activity is tightly regulated at several levels, providing new avenues for blocking these enzymes. What are the different approaches that can be used to target MMPs, and which of these might lead to new therapeutic strategies for cancer?

The costs of reproduction in plants

Abstract: Contents Summary321 I. Introduction321 II. Theory on costs of reproduction322 III. Methodological aspects324 IV. Empirical evidence328 V. Plant size and costs of reproduction330 VI. Costs of reproduction in sexually dimorphic plants331 VII. Compensation of the costs333 VIII. Concluding comments and future perspectives336 Acknowledgements337 References337 Summary This review reports on the processes associated with costs of reproduction, including some theoretical considerations, definitions and methodological aspects, followed by a list of the situations where costs are difficult to find. Despite some exceptions, case studies, examined by trade-offs between reproduction and other life-history traits, generally support the predictions of the cost of reproduction hypothesis. The cost of reproduction as an evolutionary determinant of sexual dimorphism in life history traits in dioecious species was specifically tested, considering that the higher cost of reproduction in females has driven the life history traits related to sexual dimorphism. Females of woody dioecious species were consistently smaller than males supporting the costs of reproduction hypothesis. By contrast, females of herbaceous perennials were generally the larger sex, which did not fit the expectations of the hypothesis. Finally, the mechanisms that enable the compensation of the reproductive costs are detailed, including the plastic responses of photosynthesis and growth, the effects of the timing of investment, plant architecture and plant physiological integration.

Protease degradomics: a new challenge for proteomics.

Abstract: Degradomics — the application of genomic and proteomic approaches to identify the protease and protease-substrate repertoires, or 'degradomes', on an organism-wide scale — promises to uncover new roles for proteases in vivo. This knowledge will facilitate the identification of new pharmaceutical targets to treat disease. Here, we review emerging degradomic techniques and concepts.

Defective Prelamin A Processing and Muscular and Adipocyte Alterations in Zmpste24 Metalloproteinase-Deficient Mice

Abstract: The mouse ortholog of human FACE-1, Zmpste24, is a multispanning membrane protein widely distributed in mammalian tissues1,2 and structurally related to Afc1p/ste24p, a yeast metalloproteinase involved in the maturation of fungal pheromones3. Disruption of the gene Zmpste24 caused severe growth retardation and premature death in homozygous-null mice. Histopathological analysis of the mutant mice revealed several abnormalities, including dilated cardiomyopathy, muscular dystrophy and lipodystrophy. These alterations are similar to those developed by mice deficient in A-type lamin4, a major component of the nuclear lamina5, and phenocopy most defects observed in humans with diverse congenital laminopathies6,7,8. In agreement with this finding, Zmpste24-null mice are defective in the proteolytic processing of prelamin A. This deficiency in prelamin A maturation leads to the generation of abnormalities in nuclear architecture that probably underlie the many phenotypes observed in both mice and humans with mutations in the lamin A gene. These results indicate that prelamin A is a specific substrate for Zmpste24 and demonstrate the usefulness of genetic approaches for identifying the in vivo substrates of proteolytic enzymes.

First-principles study of the rocksalt–cesium chloride relative phase stability in alkali halides

Abstract: We present a detailed investigation of observable properties associated with the relative stability of the rocksalt ( B1) and cesium chloride (B2) phases in the AX (A5Li, Na, K, Rb, Cs; X5F, Cl, Br, I! crystal family. Thermodynamic B1!B2 transition pressures and DY 5Y (B2)2Y (B1) differences in total energies, volumes, and bulk moduli at zero and transition pressures are computed following a localized Hartree-Fock method. The arrangement of the data in clear trends is shown to be mainly dominated by the cation atomic number. This behavior is well interpreted in terms of a variety of microscopic arguments that emerge from ~i! the evaluation of the energy Hessian at the B1 and B2 points and ~ii! the decomposition of the energy and pressure in anionic and cationic classical and quantum-mechanical contributions.

Regulation of cyclin-Cdk activity in mammalian cells.

Abstract: Cell cycle progression is driven by the coordinated regulation of the activities of cyclin-dependent kinases (Cdks). Of the several mechanisms known to regulate Cdk activity in response to external signals, regulation of cyclin gene expression, post-translational modification of Cdks by phosphorylation-dephosphorylation cascades, and the interaction of cyclin/Cdk complexes with protein inhibitors have been thoroughly studied. During recent years, much attention has also been given to mechanisms that regulate protein degradation by the ubiquitin/proteasome pathway, as well as to the regulation of subcellular localization of the proteins that comprise the intrinsic cell cycle clock. The purpose of the present review is to summarize the most important aspects of the various mechanisms implicated in cell cycle regulation.

The Determinants of Football Match Attendance Revisited: Empirical Evidence From the Spanish Football League

Abstract: An attendance equation is estimated using data on individual games played in the Spanish First Division Football League. The specification includes as explanatory factors: economic variables, quality, uncertainty and opportunity costs. The authors concentrate the analysis on some specification issues such as controlling the effect of unobservables given the panel data structure of the data set, the type of functional form, and the potential endogeneity of prices. The authors obtain the expected effects on attendance for all the variables. The estimated price elasticities are, in general, smaller than one in absolute value but are sensitive to the specification issues, in particular, the endogeneity of prices.

Parametric Decomposition of a Generalized Malmquist Productivity Index

Abstract: This paper provides a parametric decomposition of a generalized Malmquist productivity index which takes into account scale economies. Unlike Balk (2001), the contribution of scale economies to productivity change is evaluated without recourse to scale efficiency measures, which are neither bounded for globally increasing, decreasing, or constant returns to scale technologies nor for ray-homogeneous technologies. An empirical application using panel data from Spanish savings banks is included. This application shows the advantages of the suggested method compared to Balk's approach. The results show an increase of total factor productivity which can be mainly attributed to technical progress and the positive effect of returns to scale.

Melatonin regulation of antioxidant enzyme gene expression

Abstract: Antioxidant enzymes (AOEs) are part of the primary cellular defense against free radicals induced by toxins and/or spontaneously formed in cells. Melatonin (MLT) has received much attention in recent years due to its direct free radical scavenging and antioxidant properties. In the present work we report that MLT, at physiological serum concentrations (1 nM), increases the mRNA of both superoxide dismutases (SODs) and glutathione peroxidase (GPx) in two neuronal cell lines. The MLT effect on both SODs and GPx mRNA was mediated by a de novo synthesized protein. MLT alters mRNA stability for Cu-Zn SOD and GPx. Experiments with a short time treatment (pulse action) of MLT suggest that the regulation of AOE gene expression is likely to be receptor mediated, because 1-h treatment with MLT results in the same response as a 24-h treatment.

Evidence of intellectual capital measurement from Asia, Europe and the Middle East

Abstract: The purpose of this empirical study is to investigate the current state of best practices in the trans‐disciplinary field of intellectual capital (IC) management and measurement. First, this paper is intended to provide a conceptual framework for IC analysis. Second, it explores interesting factors regarding the dynamics of measuring and reporting IC in pioneer firms in Asia, Europe and the Middle East. After an in‐depth case analysis of leading firms in this field, a holistic IC model is discussed, which involves managing, measuring and reporting on IC. Finally, avenues for further research are suggested.

Variability of fish consumption within the 10 European countries participating in the European Investigation into Cancer and Nutrition (EPIC) study

Abstract: OBJECTIVE: To describe and compare the consumption of total fish (marine foods) and the fish sub-groups - white fish, fatty fish, very fatty fish, fish products and crustacea, in participants from the European Investigation into Cancer and Nutrition (EPIC) study. DESIGN: Cross-sectional analysis of dietary intake using a computerised standardised 24-hour recall interview. Crude means, means and standard errors adjusted by age, season and day of the week were calculated, stratified by centre and gender. SETTING: Twenty-seven redefined centres in the 10 European countries participating in the EPIC study. SUBJECTS: In total, 35 955 subjects (13 031 men and 22 924 women), aged 35-74 years, selected from the main EPIC cohort. RESULTS: A six- to sevenfold variation in total fish consumption exists in women and men, between the lowest consumption in Germany and the highest in Spain. Overall, white fish represented 49% and 45% of the intake of total fish in women and men, respectively, with the greatest consumption in centres in Spain and Greece and the least in the German and Dutch centres. Consumption of fatty fish reflected that of total fish. However, the greatest intake of very fatty fish was in the coastal areas of northern Europe (Denmark, Sweden and Norway) and in Germany. Consumption of fish products was greater in northern than in southern Europe, with white fish products predominating in centres in France, Italy, Spain, The Netherlands and Norway. Intake of roe and roe products was low. The highest consumption of crustacea was found in the French, Spanish and Italian centres. The number of fish types consumed was greater in southern than in northern Europe. The greatest variability in consumption by day of the week was found in the countries with the lowest fish intake. CONCLUSIONS: Throughout Europe, substantial geographic variation exists in total fish intake, fish sub-groups and the number of types consumed. Day-to-day variability in consumption is also high.

Numerical Simulation of the Dynamic Effects Due to Impeller-Volute Interaction in a Centrifugal Pump

Abstract: We show the capability of a numerical simulation in capturing the dynamic and unsteady flow effects inside a centrifugal pump due to the impeller-volute interaction. The object of the study is a commercial centrifugal water pump with backward curved blades, which is built within a vaneless single tongue volute. For the numerical simulation, the viscous Navier-Stokes equations are handled with an unsteady calculation and the sliding mesh technique is applied to take into account the impeller-volute interaction. In keeping the unsteady terms of the equations active it is possible to correctly simulate the effects of the blade passage in front of the tongue and both the flow and pressure fluctuations induced. Time averaged numerical results are compared with the experimental performance curve. The numerical flow analysis allows the study of different variables which are always difficult to measure experimentally. The dynamic variables obtained with the proposed numerical model are compared with the experimental data

Metal‐Nanoparticles Based Electroanalysis

Abstract: A general view of the electroanalytical applications of metal-nanoparticles in the last decade is discussed in this review. The electrocatalytical properties of various metal-nanoparticles, the employment of nanoparticles in electrochemical sensors and the use of colloidal gold as electrochemical label (no other metal nanoparticle was found to act as a label in electrochemistry) are described. Also, a description of the fabrication and electrochemical characterization of metal-nanoparticle modified electrodes is given. Finally, due to its growing importance, semiconductor-nanoparticle modified electrodes are described, although they can not be strictly considered as electroanalytical devices.

Kinetics of the deep oxidation of benzene, toluene, n-hexane and their binary mixtures over a platinum on γ-alumina catalyst

Abstract: In this work, the catalytic oxidation of benzene, toluene and n -hexane in air, both alone and in binary mixtures, over a commercial Pt on γ-alumina catalyst was studied. Studies have been carried out at concentrations of up to 4200 ppmV, in a laboratory fixed-bed catalytic reactor. Results for single compounds show that temperature at which 50% conversion is attained ( T 50 ) increases as concentration increases for benzene and toluene, while the opposite behaviour is observed for n -hexane. Results for mixtures show that, while the presence of n -hexane does not affect the conversion of benzene and toluene, the presence of benzene or toluene inhibits the combustion of hexane, and the aromatic compounds inhibits each other when are reacted together. Results obtained in absence of mass transfer limitations were fit to kinetic expressions: simple Mars–Van Krevelen kinetic expressions for single compounds, and a modified Mars–Van Krevelen mechanism, considering competitive adsorption of the hydrocarbons, for binary mixtures.

A Structural Equation Model of Parental Involvement, Motivational and Aptitudinal Characteristics, and Academic Achievement

Abstract: The authors used the structural equation model (SEM) approach to test a model hypothesizing the influence of parental involvement on students' academic aptitudes, self-concept, and causal attributions, as well as the influence of the 3 variables on academic achievement The theoretical model was contrasted in a group of 12- to 18-year-old adolescents (N = 261) attending various educational centers The results indicate that (a) parental involvement had a positive and significant influence on the participant's measured characteristics; (b) causal attribution was not causally related to self-concept or academic achievement when the task involved finding causes for success, but, self-concept and causal attributions were found to be significantly and reciprocally related when the task involved finding causes accounting for failure; (c) self-concept was statistically and predominantly causally related to academic achievement, but not vice versa; and (d) aptitude and self-concept accounted for academic

Effects of temperature and food quality on anuran larval growth and metamorphosis

Abstract: Summary 1. Anurans exhibit high levels of growth-mediated phenotypic plasticity in age and size at metamorphosis. Although temperature and food quality exert a strong influence on larval growth, little is known about the interacting effects of these factors on age and size at metamorphosis. 2. Plasticity in growth rates, maximum larval mass, mass loss, larval period and size at metamorphosis was examined in Iberian Painted Frogs ( Discoglossus galganoi Capula, Nascetti, Lanza, Bullini & Crespo 1985) under different combinations of temperature and diet quality. 3. Temperature and diet had strong effects on the maximum size reached by tadpoles throughout the premetamorphic stages. Larval body mass varied inversely with temperature. The effect of diet depended on temperature; larvae fed on a ‘carnivorous’ diet (rich in protein and lipids) achieved a larger size than larvae offered an ‘herbivorous’ diet (rich in carbohydrates) at 17 ° C but not at 12 or 22 ° C. 4. Larval period was insensitive to diet composition, and varied only with temperature. Primarily the interacting effects of food quality and temperature affected size at metamorphosis. Size at metamorphosis varied inversely with temperature under the plant- and the animal-based diets. However, the carnivorous diet resulted in bigger metamorphs at 17 and 22 ° C, but did not influence final mass at 12 ° C. Maximum size over the larval period explained most of the variation in mass loss after the premetamorphic growing phase.

Characterization of a Self-Transferable Plasmid from Salmonella enterica Serotype Typhimurium Clinical Isolates Carrying Two Integron-Borne Gene Cassettes Together with Virulence and Drug Resistance Genes

Abstract: An unusual self-transferable virulence-resistance plasmid (pUO-StVR2) was found in nine multidrug-resistant (ACSSuT phenotype) Salmonella enterica serotype Typhimurium clinical isolates that were assigned to four different phage types and a single and distinctive XbaI pulsed-field gel electrophoresis profile. pUO-StVR2 is an IncFII plasmid of about 140 kb in length carrying the spvA, spvB, and spvC (Salmonella plasmid virulence) and rck (resistance to complement killing) genes. It also carries the oxa1/aadA1a (ampicillin resistance and streptomycin-spectinomycin resistance) gene cassette configuration located within a class 1 integron with qacEDelta1/sul1 (ammonium antiseptics resistance and sulfadiazine resistance); the transposon genes merA, tnpA, and tnpR (mercury resistance, transposase, and resolvase of Tn21, respectively); and the catA1 (chloramphenicol resistance) and tet(B) (tetracycline resistance) genes. The insertion of resistance genes into a Salmonella virulence plasmid constitutes a new and interesting example of plasmid evolution and presents a serious public health problem

A decision support system for applying failure mode and effects analysis

Abstract: This study describes an alternative way of applying failure mode and effects analysis (FMEA) to a wide variety of problems. It presents a methodology based on a decision system supported by qualitative rules which provides a ranking of the risks of potential causes of production system failures. By providing an illustrative example, it highlights the advantages of this flexible system over the traditional FMEA model. Finally, a fuzzy decision model is proposed, which improves the initial decision system by introducing the element of uncertainty.

Mergers and technical efficiency in Spanish savings banks: A stochastic distance function approach

Abstract: The aim of this paper is to test the temporal variation of technical efficiency of Spanish savings banks during the period 1985–1998. Furthermore, we test whether merged and non-merged firms have different levels and temporal patterns of technical efficiency. A stochastic output distance function (R.W. Shephard, Theory of Cost and Production Functions, Princeton University Press, Princeton, NJ) is employed to accommodate multiple output technology. The distance function provides the advantage that it does not need information about prices, so it can accommodate the multi-product nature of the financial sector only using the quantities as data (an important point when the assumptions about perfectly competitive markets are unlikely to be met). The temporal variation of efficiency is modeled extending the Battese and Coelli (Journal of Productivity Analysis 3 (1992) 153–169) approach in two ways: relaxing the monotonicity of the temporal variation pattern of the efficiency term, and allowing for different patterns of efficiency change between merged and non-merged firms.

A classification of covalent, ionic, and metallic solids based on the electron density.

Abstract: The electron density of crystals contains all of the information required to complete a classification of their bonding types. We propose here a set of three different indexes, flatness, charge transfer, and molecularity, easily obtained from the experimental or theoretical electron density, which give rise to a classification in close resemblance to the classical van Arkel−Ketelaar diagrams.

High-performance capillary electrophoretic method for the quantification of 5-methyl 2'-deoxycytidine in genomic DNA: Application to plant, animal and human cancer tissues

Abstract: A new approach to the evaluation of the relative degree of genomic DNA methylation through the quantification of 2'-deoxynucleosides is proposed. Detection and quantification of 5-methyl 2'-deoxycytidine in genomic DNA has been performed using micellar high-performance capillary electrophoresis (HPCE) with UV-Vis detection. This approach has been demonstrated to be more sensitive and specific than other HPCE methods for the quantification of DNA methylation degree and also to be faster than other HPLC-based methods. The detection and quantification of nucleosides through enzymatic hydrolyses notably increases the specificity of the technique and allows its exploitation in the analysis of poorly purified and/or concentrated DNA samples such as those obtained from meristematic plant regions and paraffin-embedded tissues.

Origin and Significance of Isotope Shifts in Pennsylvanian Carbonates (Asturias, NW Spain)

Abstract: The primary variability of the composition and properties of seawater is much greater in the shallow coastal zones than in the main body of ocean water. An inadequate understanding of this variability, as well as different diagenetic environments, severely limit the interpretation of the stable-isotope record of shoalwater carbonates. In order to investigate this primary and diagenetic variability along a Bashkirian-Moscovian platform-to-basin transect, 13C and 18O analyses have been performed on more than 1000 matrix micrite, carbonate cement, and brachiopod shell samples. In isotope analysis, these different carbonate materials tend to complement each other, inasmuch as they have different advantages and shortcomings. The resulting data reveal spatial trends in 13C and 18O signatures from platform top (lower values) to basin (higher values). In the case of 13C from pristine brachiopods, this trend can be explained by the long residence time (aging) of platform-top water masses. In the case of brachiopod 18O, this variance is interpreted to reflect temperature differences between warm surface and colder bottom water separated by a permanent thermocline at about 150 to 200 m beneath the shelf break. Micrite and marine cement isotopic values from the platform interior were reset (lowered) during pervasive early meteoric diagenesis. In contrast, micrite and marine cement isotopic values from the outer platform, slope, and basin show higher values close to the assumed Pennsylvanian seawater isotopic composition. This implies that isotopic data from shoalwater carbonates (including pristine brachiopod shells) might not necessarily reflect paleoceanographic trends of the open-ocean water masses because of changes in coastal water-mass isotope signature and interaction with early meteoric fluids.

Autocatalyzed and Ion-Exchange-Resin-Catalyzed Esterification Kinetics of Lactic Acid with Methanol

Abstract: The esterification kinetics of lactic acid with methanol without addition of catalyst and catalyzed by ion-exchange resins are presented in this work. The effect of catalyst type, stirrer speed, catalyst size, catalyst loading, initial reactant ratio, and temperature on reaction kinetics was evaluated. Experimental reaction rates were correlated by some models based on homogeneous and heterogeneous (dual- and single-site mechanisms) approaches. Nonideality of the liquid phase was taken into account by using activities instead of mole fractions. Prediction of the activity coefficients was made by UNIFAC. Parameters of the different models were obtained by the simplex search method.

Market orientation and social services in private non‐profit organisations

Abstract: Very little attention has been devoted so far to the study of the market orientation concept in private non‐profit organisations. However, there is a general agreement concerning the positive effects that this concept’s adoption has on the non‐profit services implementation as well as on these organisations’ long‐term success. Thus this paper aims at obtaining further empirical evidence on this field of research using a private foundations sample. Nevertheless, it is considered that the distinctive and specific nature of private non‐profit organisations’ activities deserves the development of a special instrument to evaluate their degree of market orientation. In this sense, one of this study’s main contributions is the development of a market orientation measurement scale which accounts for the peculiarities of private non‐profit organisations’ operations. Additionally, the study proves the positive effect of market orientation on the non‐profit outcomes and on the fulfilment of these organisations’ missions.