Showing papers by "University of Extremadura published in 1991"

Erythrocyte free radical scavenger enzymes in bicycle professional racers. Adaptation to training.

Abstract: This study was designed to investigate the influence of endurance training on the activities of the scavenger enzymes superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GSH-Px) measured in erythrocytes from sedentary subjects, amateur bicycle racers and in professional bicycle racers who were cycling in two real cyclist contests including the top-class race Vuelta a Espana (VCE). Under resting conditions the SOD activity was higher (p less than 0.01) in cyclists than in controls. The activities of CAT and GSH-Px were higher (p less than 0.05 and p less than 0.01, respectively) under resting conditions in professional cyclists versus measured both in sedentary subjects and amateur cyclists. The enzyme activities were not modified significantly in professional cyclists after a bout of exercise of 22 km in 5 hrs, but the SOD activity was increased (p less than 0.05) and CAT activity reduced (p less than 0.05) after 2800 km in 20 days (VCE). The present results shown that aerobic endurance training, when at a professional level, produces an increase in the erythrocyte activities of the main free radicals scavenger enzymes.

Radial distribution function for hard spheres.

Abstract: The radial distribution function g(r) provided by the solution of the Percus-Yevick (PY) equation for hard spheres is rederived in terms of the simplest Pad\'e approximant of a function defined in the Laplace space that is consistent with the following physical requirements: g(r) is continuous for rg1, the isothermal compressibility is finite, and the zeroth- and first-order coefficients in the density expansion of g(r) must be exact. An explicit expression for the solution of the generalized mean-spherical approximation (GMSA) is obtained as a simple extension involving two new parameters, which are determined by imposing two conditions: (i) the virial and the compressibility routes to the equation of state agree consistently, and (ii) this equation of state coincides with that of Carnahan and Starling [J. Chem. Phys. 51, 635 (1969)]. The second- and third-order coefficients in the density expansion of g(r) given by the GMSA are compared with the exact ones and with those given by the PY equation.

Debrisoquine oxidation phenotype during neuroleptic monotherapy

Abstract: The debrisoquine oxidation phenotype was determined in 91 schizophrenic patients on monotherapy with different neuroleptics and in 67 untreated healthy volunteers. The prevalence of poor metabolizers of debrisoquine was significantly higher in the patients (46.2%) than in the healthy subjects (7.5%). Treatment with phenothiazine antipsychotics (chlorpromazine, levomepromazine and thioridazine) was associated with a higher debrisoquine metabolic ratio than treatment with haloperidol. On the other hand, treatment with clothiapine appeared not to interfere with debrisoquine oxidation. Oral administration of 50 mg thioridazine daily to 8 healthy subjects resulted in a marked increase in the debrisoquine metabolic ratio and 4 of them were transformed into phenotypically poor metabolizers. The results confirm the fact that phenothiazines, and to a lesser extent haloperidol, inhibit the oxidative metabolism of debrisoquine. They show also that clothiapine administration does not disturb the debrisoquine metabolic ratio.

Microbial study of Casar de Cáceres cheese throughout ripening

Abstract: Six batches of Casar de Caceres raw ewes' milk cheeses were examined throughout their ripening. Three were made in winter, the others in spring. The microbial counts in the interior of the cheeses were ∼1·5 log units higher in the winter cheeses for total viable counts, lactic streptococci and leuconostocs, and >2 log units higher for total enterobacteria, coliforms and faecal coliforms in the 60 d samples. Staphylococci were not detected after day 15 of maturation in spring cheeses, but reached 1 log unit at day 60 in the interior of winter cheeses. In the surface samples, differences in microbial counts were more marked. Values of some physicochemical indices, such as pH, % moisture content and % NaCl were also determined.

Phagocytic Function of Blood Neutrophils in Sedentary Young People after Physical Exercise

Abstract: The effect of exhaustive running exercise on the phagocytic function of blood polymorphonuclear neutrophils in sedentary young men and women has been studied. Adherence capacity to the endothelium, spontaneous mobility, chemotaxis and ingestion of Candida albicans were not modified after physical exercise. However, opsonization of Candida albicans as well as candidicide power increased significantly in men and women after exercise. The immediate advantages of physical exercise on the phagocytic immune response is discussed.

Staphylococci isolated from healthy goats.

Abstract: A study was made of the staphylococcal population on the skin and on the nasal mucosa and in the milk of 133 healthy goats Of a total of 346 strains isolated and characterised as belonging to the genus Staphylococcus, 74 (214%) were coagulase-positive (68 S aureus and 6 S hyicus), and 272 (786%) coagulase-negative The novobiocin-sensitive species S haemolyticus (235%), S warneri (165%), S epidermidis (118%), S chromogenes (85%), S caprae (66%) and S hyicus (26%), and the novobiocin-resistant species S xylosus (85%), S sciuri (74%), S saprophyticus (48%), S cohnii (22%), S lentus (11%), S equorum (11%) and S kloosii (11%) were identified Twelve (44%) of coagulase-negative strains remained unidentified Strains isolated in the skin of the udder and teats of the 133 goats were mainly novobiocin-sensitive coagulase-negative staphylococci, the most prevalent species being S haemolyticus, S warneri and S epidermidis Staphylococci indicative of subclinical infection were determined in the milk of 47 (353%) of the 133 goats sampled

Path integral simulation of the free energy of (Lennard-Jones) neon

Abstract: The quantum mechanical contribution to the free energy of simple fluids can be conveniently determined by path integral simulation and ‘λ-integration’, choosing the classical fluid as reference system. In this paper the method is applied to liquid Lennard-Jones (LJ) neon. The properties of the quantum mechanical and the classical liquids are compared with each other and with experimental data.

Acute effects of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine in a model of rat designated a poor metabolizer of debrisoquine.

Abstract: The relationship between oxidative polymorphisms and the cause of Parkinson's disease is controversial. The drug l-methyl-4-phenyl-1, 2, 3, 6-tetrahydropyridine (MPTP), which induces parkinsonism in humans and in some animal models, is metabolized by cytochrome P450 db1 isozyme (the same enzymatic system implicated in 4-hydroxylation of debrisoquine). In this study, we treated females of three rat species, which differ in their ability to hydroxylate debrisoquine, with MPTP (three doses of 30 mg/kg s.c. at 12-h intervals), and we measured their motor activity and brain monoamine levels. Female dark-adapted rats (poor metabolizers of debrisoquine) showed a more pronounced and more maintained reduction of their motor activity after treatment with MPTP. MPTP-treated, dark-adapted rats also had a depletion of noradrenaline in the diencephalon and a depletion of dopamine and serotonine and their respective metabolites in the limbic system when compared with the other two species. These results suggest that oxidative polymorphism of debrisoquine plays a role in the acute effects of MPTP.

Electron correlation and solvation effects

Abstract: The ab initio version of the polarizable continuum model designed to describe solvation phenomena has recently been implemented by including electron correlation effects. We examined the performance of one of the versions of the method presented in Part 1 by taking into consideration, for three simple solutes (H 2 O, CH 3 OH and H 2 CO), four basis sets (STO-4G, 6-31G, 6-31G and 6-31G)**. The calculations were performed for four different dielectric media, with permittivities ranging from 2.28 to 78.3.

Toxic shock syndrome toxin 1 (TSST-1) production by staphylococci isolated from goats and presence of specific antibodies to TSST-1 in serum and milk.

Abstract: The ability of staphylococcal strains isolated from different anatomical sites in 133 healthy goats to produce toxic shock syndrome toxin 1 (TSST-1) and the presence of antibodies to this toxin in serum and milk were studied. The enzyme-linked immunosorbent assay method was used to detect both the toxin and the presence of antibodies. Of a total of 342 staphylococcal strains studied, 86 (25.2%) were found to produce TSST-1. Specific antibodies to TSST-1 were found in the serum of 57 (42.9%) of the animals studied and the milk of 63 (47.4%) of the animals. These results suggest that goats are frequently in contact with staphylococci that produce TSST-1, a toxin usually associated with Staphylococcus aureus strains isolated from cases of toxic shock syndrome in humans.

Indentation‐Induced Cracks and the Toughness Anisotropy of 9.4‐mol%‐Yttria‐Stabilized Cubic Zirconia Single Crystals

Abstract: The crack systems associated with room-temperature Vickers indentations on (001) surfaces in 9.4-mol%-Y{sub 2}O{sub 3}-stabilized cubic ZrO{sub 2} single crystals are examined. The indentation-induced radial cracks are not always perpendicular to the free surface, as is usually assumed, and the surface traces are therefore not a reliable guide to the nature of the cracking. In fact, indentations with (100) diagonals do not form cracks on (010), but form secondary radial cracks on inclined planes and noncoplanar median cracks on 110 or 1{bar 1}0.

On duffing oscillators with slowly varying parameters

Abstract: A method of Krylov-Bogoliubov type, which gives the approximate solution in terms of Jacobi elliptic functions, is used for the study of perturbed Duffing oscillators with slowly varying parameters: d dt [μ(τ) x ] + c 1 (τ)x + c 3 (τ)x 3 + ef(x, x , τ) = 0 . This method is a natural generalization of the usual Krylov-Bogoliubov method that is only valid when c3(τ)x3 is of e order. Two examples are given. One is a pure cubic oscillator (c1 = 0) with variable mass and linear damping, f(x, x ) = x , for which a simple accurate approximate solution is found. The other is a pendulum with variable length and damping proportional to the velocity for which an approximate analytical expression for the rate of variation of the oscillation amplitude is obtained, and successfully compared with the numerically calculated result and with that obtained using the normal Krylov-Bogoliubov method.

A Monte Carlo based method of including gamma self-absorption for the analysis of environmental samples

Abstract: We propose a new method to calculate the full-energy-peak efficiency of Ge(Hp) detectors, including gamma self-absorption, using a Monte Carlo technique We have studied several samples geometries, which are the most commonly used in environmental radioactivity, Petri vial and Marinelli beakers, supposing different densities for the material in the sample, between 04 and 16 g/cm3 For each geometry we have found an important change of self-absorption on density and we have calculated the dependence of full-energy-peak efficiency on sample density for a set of energies between 100 and 2000 keV

The major exoglucanase from Candida albicans: a non-glycosylated secretory monomer related to its counterpart from Saccharomyces cerevisiae.

Abstract: Exoglucanases secreted by two different strains from Candida albicans have been purified to homogeneity. The purified enzyme from each strain behaved as a non-glycosylated monomer (molecular weight 38,000) that was identical in terms of sodium dodecyl sulphate/polyacrylamide gel electrophoresis comigration, amino acid analysis and amino terminal sequence. The amino acid composition was similar to that of the major exoglucanase from Saccharomyces cerevisiae. In addition, these two enzymes displayed a 50% homology in the first 35 amino acids of the amino terminus. Antibodies against the deglycosylated exoglucanase (treated with Endo H) from S. cerevisiae were reactive with the exoglucanase from C. albicans and vice versa. Immunoblotting proved to be a semiquantitative method to detect C. albicans antigen in culture fluids. The exoglucanase from C. albicans appears to enter the secretory pathway without undergoing N-glycosylation.

Macrophage-like cells invading the suboptic necrotic centres of the avian embryo diencephalon originate from haemopoietic precursors

Abstract: Macrophage-like cells have been previously shown within the suboptic necrotic centres of chick embryos during the period just previous to, and coinciding with, growth of the earliest optic axons through suboptic necrotic centres. In this paper, light and electron microscopy observations of chick embryos suggest that these macrophage-like cells originate from blood cells. Immunocytochemical techniques in chick-quail yolk sac chemeras, constituted of a chick embryo and a quail yolk sac, revealed that the macrophage-like cells within the suboptic necrotic centres are labelled with anti-MB1 antibody, which is specific for quail haemopoietic and endothelial cell lineage. These findings demonstrate that these phagocytic cells are of blood cell lineage, and originate in the extraembryonic tissues of the yolk sac. Diffuse staining around some suboptic necrotic centre macrophage-like cells suggests that they release MB1 antigens which may play a role in the growth of the optic axons through the suboptic necrotic centres.