Showing papers by "University of Valencia published in 1992"

Exhaustive physical exercise causes oxidation of glutathione status in blood: prevention by antioxidant administration.

Abstract: We have studied the effect of exhaustive concentric physical exercise on glutathione redox status and the possible relationship between blood glutathione oxidation and blood lactate and pyruvate levels. Levels of oxidized glutathione (GSSG) in blood increase after exhaustive concentric physical exercise in trained humans. GSSG levels were 72% higher immediately after exercise than at rest. They returned to normal values 1 h after exercise. Blood reduced glutathione (GSH) levels did not change significantly after the exercise. We have found a linear relationship between GSSG-to-GSH and lactate-to-pyruvate ratios in human blood before, during, and after exhaustive exercise. In rats, physical exercise also caused an increase in blood GSSG levels that were 200% higher after physical exercise than at rest. GSH levels did not change significantly. Thus, both in rats and humans, exhaustive physical exercise causes a change in glutathione redox status in blood. We have also found that antioxidant administration, i.e., oral vitamin C, N-acetyl-L-cysteine, or glutathione, is effective in preventing oxidation of the blood glutathione pool after physical exercise in rats.

The capacitated arc routing problem : lower bounds

Abstract: In this paper, we consider the Capacitated Arc Routing Problem (CARP), in which a fleet of vehicles, based on a specified vertex (the depot) and with a known capacity Q, must service a subset of the edges of a graph, with minimum total cost and such that the load assigned to each vehicle does not exceed its capacity. New lower bounds are developed for this problem, producing at least as good results as the already existing ones. Three of the proposed lower bounds are obtained from the resolution of a minimum cost perfect matching problem. The fourth one takes into account the vehicle capacity and is computed using a dynamic programming algorithm. Computational results, in which these bounds are compared on a set of test problems, are included.

Characterization of cell wall proteins from yeast and mycelial cells of Candida albicans by labelling with biotin: comparison with other techniques.

Abstract: Candida albicans ATCC 26555 blastoconidia and blastoconidia bearing germ tubes were metabolically labelled by incubating the cells with 14C-labelled protein hydrolysate and were subsequently tagged with biotin. Double-labelled (radioactive and biotinylated) cell wall proteins and glycoproteins were extracted from intact cells of both growth forms by treatment with 2-mercaptoethanol (beta ME) and with beta-glucanases (Zymolyase) after treatment with beta ME. The beta ME- and Zymolyase-extracts were separated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and western blotted (immunoblotted) to nitrocellulose paper. Polyacrylamide gels were stained with Coomassie blue and processed for fluorography. Western blot analysis was performed either with peroxidase conjugated-concanavalin A (ConA) or Extravidin. Blotted proteins were also reacted with polyclonal antibodies and monoclonal antibodies against mannoprotein components from mycelial cell walls of the ATCC 26555 strain. Labelling with biotin allowed identification of a complex array of cell wall protein and glycoprotein components within a very wide molecular mass range (from 650 to 13 kDa). These appeared to be genuine cell wall components. Biotinylated high-molecular-mass glycoproteins that were not stained with Coomassie blue or that appeared as poorly resolved polydisperse bands by indirect ConA-peroxidase staining of Western blots were detected as sharply defined bands following reaction with the Extravidin-peroxidase conjugate. Biotinylated molecules retained unaltered reactivities against ConA, polyclonal antibodies, and monoclonal antibodies.

Identification of a 58-kilodalton cell surface fibrinogen-binding mannoprotein from Candida albicans.

Abstract: Treatment of both yeast (blastoconidia) and hyphal (blastoconidia with germ tubes) cells of Candida albicans with beta-mercaptoethanol (beta ME) releases a complex array of cell wall-bound proteins and glycoproteins. Analysis by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and Western immunoblotting with fibrinogen-anti-fibrinogen antibody allowed the identification of a 58-kDa mannoprotein (mp58) in both extracts which specifically interacts with human fibrinogen. Treatment of intact cells with low concentrations of beta-glucanase (Zymolyase 20T) for short periods or with beta ME abolished or significantly reduced binding of fibrinogen. A rabbit polyclonal antiserum was raised against the purified mp58 species released by beta ME from germinated blastoconidia (PAb anti-mp58). By Western blotting, the antiserum cross-reacted with the homologous 58-kDa fibrinogen-binding mannoprotein present in beta ME extracts from blastoconidia, and by indirect immunofluorescence, the antiserum labelled both yeast cells and hyphae, yet reactivity was found primarily on the cell surface of filamentous forms. Immunostaining of human infected tissue sections with PAb anti-mp58 showed that the mp58 species is also expressed in vivo; in this case, the species is in the forms of both yeast and hyphal elements similarly labelled by the antiserum. Purified immunoglobulin G fraction from the antiserum did not alter the binding of fibrinogen as determined by a modified enzyme-linked immunosorbent assay and Western blotting. The N- and O-glycosidically linked carbohydrates represent 18 to 20% and 3 to 4%, respectively, of the molecular mass of the mp58. O-linked sugar residues may be involved in the interaction of the molecule with fibrinogen.

Aeromonas allosaccharophila sp. nov., a new mesophilic member of the genus Aeromonas.

Abstract: Phenotypic and genetic studies were performed on some atypical aeromonad strains of uncertain taxonomic position. 16S rRNA gene sequence analysis revealed that these strains represent a hitherto unknown genetic line within the genus Aeromonas, for which the name Aeromonas allosaccharophila sp. nov. is proposed. The type strain is CECT 4199.

Reference Priors in a Variance Components Problem

Abstract: The ordered group reference prior algorithm of Berger and Bernardo (1989b) is applied to the balanced variance components problem. Besides the intrinsic interest of developing good noninformative priors for the variance components problem, a number of theoretically interesting issues arise in application of the proposed procedure. The algorithm is described (for completeness) in an important special case, with a detailed heuristic motivation.

Pharmacological Characterization and Autoradiographic Localization of Histamine H2 Receptors in Human Brain Identified with [125I]Iodoaminopotentidine

Abstract: 125I-Aminopotentidine (125I-APT), a reversible probe of high specific radioactivity and high affinity and selectivity for the H2 receptor, was used to characterize and localize this histamine receptor subtype in human brain samples obtained at autopsy. On membranes of human caudate nucleus, specific 125I-APT binding at equilibrium revealed a single component, with a dissociation constant of 0.3 nM and maximal capacity of about 100 fmol/mg of protein. At 0.2 nM, 125I-APT specific binding, as defined with tiotidine, an H2-receptor antagonist chemically unrelated to iodoaminopotentidine, represented 40-50% of the total. Specific 125I-APT binding was inhibited by a series of typical H2-receptor antagonists that displayed apparent dissociation constants closely similar to corresponding values at the reference biological system, i.e., guinea pig atrium. This indicates that the pharmacology of the H2 receptor is the same in the human brain as on this reference system. However, histamine was about 10-fold more potent in inhibiting 125I-APT binding to membranes of human brain than of guinea pig brain. 125I-APT binding was also inhibited by amitriptyline and mianserin, two antidepressant drugs, in micromolar concentrations corresponding to effective plasma concentrations of treated patients. The distribution of H2 receptors was established autoradiographically with 125I-APT on a series of coronal sections of human brain after assessing the pharmacological specificity of the labeling. The highest density of 125I-APT sites was found in the basal ganglia, various parts of the limbic system, e.g., hippocampus or amygdaloid complex, and the cerebral cortex. H2 receptors displayed a laminar distribution in cerebral cortex and hippocampal formation. A low density of sites was found in cerebellum as well as in hypothalamus, the brain area where all the perikarya and the largest number of axons of histaminergic neurons are found. The widespread distribution of H2 receptors in the human brain is consistent with the alleged modulatory role of histamine mediated by this subtype of receptor.

Lipid content of Saccharomyces cerevisiae strains with different degrees of ethanol tolerance

Abstract: We analysed the fatty acid and sterol compositions of various Saccharomyces cerevisiae strains with ethanol tolerance varying from 4% to 12% (v/v) ethanol and at different concentrations of ethanol The results we obtained agree with the existence of a relationship between membrane fluidity and ethanol tolerance but they do not support a direct role of unsaturated fatty acids in this tolerance On the other hand, they support the importance of ergosterol in this phenomenon

Compound odontoma erupting in the mouth: 4-year follow-up of a clinical case.

Abstract: A case of a compound odontoma erupting in the oral cavity is presented: a follow-up study of 4 yr has been performed evaluating the possible relationship with a previous dental trauma. A discussion is presented concerning the etiologic aspects, clinical signs, diagnostic aids and therapeutic approaches to this type of lesion.

Production of the Sweet Protein Monellin in Transgetic Plants

Abstract: Monellin is a protein that elicits a flavor approximately 100,000 times sweeter than sugar on a molar basis. The protein exists naturally as a heterodimer, with its sweet flavor lost upon denaturation. A single–chain monellin gene, encoding both polypeptide chains linked by a hinge sequence, was placed under the control of constitutive and fruit–ripening specific promoters and transferred to lettuce and tomato. Expression of these genes in transgenic tomato and lettuce resulted in the accumulation of monellin protein in fruit and leaf, respectively, to significant levels. Production of monellin in transgenic fruits and vegetables represents an alternative strategy to enhance their flavor and quality.

L'anthracologie préhistorique: à propos de certains problèmes méthodologiques

Abstract: ResumeAfin d'avancer dans nos connaissances ecologiques et ethnologiques des temps passes, il etait essentiel de mettre en place une methodologie en accord avec les problemes poses. Deux themes sont developpes dans ce travail: la dispersion spatiale des taxons vegetaux dans l'ensemble du gisement et l'etude approfondie du contenu anthracologique des structures de combustion et sa relation avec celui des niveaux d'habitat.

Electrophoretic analysis of heterogeneous lipopolysaccharides from various strains of Vibrio vulnificus biotypes 1 and 2 by silver staining and immunoblotting.

Abstract: Lipopolysaccharides (LPS) of 11 strains ofVibrio vulnificus biotypes 1 and 2, isolated from an eel farm, and of 10 reference strains, were examined by SDS-polyacrylamide gel electrophoresis coupled with silver staining and immunoblotting. LPS samples were obtained from whole-cell lysates, outer membrane fragments, and extracellular products. By silver staining, only a diffuse band of low-molecular weight could be visualized in all cases except for a biotype 1 strain isolated from water. However, immunoblotting with antisera obtained against strains of biotypes 1 and 2 from eels allowed visualization of multiple O-polysaccharide chains. All biotype 2 strains, independently of their origins, belonged to the same serotype and presented the same LPS profile, whereas eel isolates of biotype 1 were serologically identical and different from the rest of tested strains of biotype 1. This is the first report of LPSs with a ladder-like structure inVibrio vulnificus.

Use of NOAA-AVHRR NDVI data for environmental monitoring and crop forecasting in the Sahel. Preliminary results

Abstract: Several studies have shown that the NDVI calculated from NOAA-AVHRR data is related to annual rainfall and primary productivity in Sahelian areas. Such correlations, however, are affected by several environmental factors and have been tested only with data accumulated during rainy seasons, which is not ideal for the prediction of crop yield. In the present study a methodology of NOAA AVHRR data processing is presented which utilizes NDVI computed only in the first part of some rainy seasons and statistically takes into account the geographical variability in land resources and atmospheric conditions. From the first results of the application of the methodology in Niger, its potential has been shown both for environmental monitoring, and, more specifically, for crop yield assessment and forecasting.

Inguinal hernia and certain risk factors.

Abstract: The are several studies on inguinal hernias that give some clues about the association between this type of hernia and certain risk factors. This association was suspected long ago but had not been demonstrated. The present study tries to correlate the origin of inguinal hernias and the physical effort of the subjects in accordance with their work activity. The results of this study show that physical effort, as a risk factor, is closely related to the appearance of inguinal hernias. A person whose work involves lifting or other strenuous exertion has a higher risk than those whose jobs are less stenouous (p < 0.05). This conclusion was reached after taking into account not only the weight lifted but also the number of years in this activity.

The influence of family expressed emotion on the course of schizophrenia in a sample of Spanish patients. A two-year follow-up study.

Abstract: A sample of 60 Spanish schizophrenic patients was studied to ascertain the relationship between their relatives' expressed emotion (EE) and relapse at follow-up. The relatives' EE and patients' relapse were operationalised following Leff & Vaughn's criteria. At nine months a significant association was not found between the relatives' EE and relapse, but this association became significant on reclassifying the relatives' EE scores after decreasing to four points the cut-off point for critical comments. At 24 months no association was found between EE and relapse. There was a tendency for patients who interrupted their medication or who did not work to relapse more frequently, particularly among the high-EE group.

Chromatin structure of the yeast SUC2 promoter in regulatory mutants.

Abstract: We have previously suggested that two positioned nucleosomes are removed from the promoter of the Saccharomyces cerevisiae SUC2 gene upon derepression by glucose starvation. To gain further insight into the changes accompanying derepression at the chromatin level we have studied the chromatin structure of the SUC2 promoter in several mutants affecting SUC2 expression. The non-derepressible mutants snf1, snf2 and snf5 present a chromatin structure characteristic of the repressed state, irrespective of the presence or absence of glucose. The non-repressible mutants, mig1 and ssn6, as well as the double mutant snfs sn6 exhibit an opened chromatin structure even in the presence of glucose. These results suggest that the DNA-binding protein encoded by MIG1 is necessary to produce the characteristic pattern of repressed chromatin and that the SNF1 protein kinase is sufficient to produce the derepressed chromatin pattern. A model is presented for the transitions that result in opening up of the chromatin structure.