Showing papers by "University of Córdoba (Spain) published in 1985"
TL;DR: Changes in the adherence, opsonization, phagocytosis, nitroblue tetrazolium reduction and antibody-dependent cell cytotoxicity of peritoneal macrophages were observed with aging in BALB/C mice.
122 citations
TL;DR: Serological surveys conducted in the 1960s indicate a high prevalence of infection of humans and domestic animals with St. Louis encephalitis (SLE), and 2 SLE virus strains have been isolated from rodents, but human disease has rarely been associated with SLE infection.
Abstract: Serologic surveys of wild and domestic birds, wild mammals, and horses were conducted during arbovirus field studies in Argentina from 1977 through 1980, a non-epizootic interval. The prevalence of neutralizing antibodies to eastern equine encephalitis (EEE) was consistently higher than to western equine encephalitis (WEE) virus in all species and all areas. The presence of antibodies in short-lived avian species and in young unvaccinated horses and the demonstration of seroconversions in horses during the period, indicated that these viruses are either enzootic in, or annually reintroduced into, Argentina. Antibodies to AG80-646, a new subtype of WEE virus isolated in the subtropical north (Chaco Province) from Culex (Melanoconion) mosquitoes, were found in horses and rodents in that region. Antibodies to the TC-83 strain of Venezuelan equine encephalitis (VEE) virus were found in all areas studied. The presence of antibodies in some horses was probably related to vaccination, but the demonstration of seroconversions in sentinel horses and of antibodies in birds and wild mammals indicates active transmission of VEE virus. In 1980 a new enzootic subtype of VEE virus (AG80-663) was isolated from mosquitoes in Chaco; neutralizing antibodies to this virus were prevalent in horses and rodents in this area. Infections with Aura and Una viruses were most common in the subtropical northern provinces. Infection with St. Louis encephalitis was prevalent and widespread, and birds, principally passerine and columbiform species, appear to be the principal hosts. An interesting and unexplained finding was the absence of arbovirus antibodies, in particular SLE antibodies in house sparrows (Passer domesticus). Antibody prevalences in horses exceeded 50% in all areas, and 12% of horses surveyed in Santa Fe Province developed antibody in a 17-month period. Antibodies to other flaviviruses were rare. A high prevalence of immunity to Maguari virus was found in horses; this agent is considered to be a potential equine pathogen. Antibodies to 2 new viruses, Barranqueras and Resistencia, which had been isolated from Cx. (Melanoconion) in Chaco Province, were found in rodents there. Immunity to Gamboa group viruses was prevalent, and birds were implicated as principal hosts.
80 citations
TL;DR: In this paper, the copper ion-pair extraction was used for the determination of perchlorate added to serum and urine samples, achieving a 3-fold increase in sensitivity over the conventional spectrophotometric method.
65 citations
TL;DR: The results support the idea that the L-arabinose forward mutation assay could replace the set of specific tester strains used by the histidine reverse mutation assay in general screening for genetic toxins.
Abstract: Strain TA102 of S. typhimurium is a new histidine-requiring mutant, particularly suited to the detection of oxidative mutagens acting at A·T base pairs. 10 oxidizing chemicals, previously tested in strain TA102, were used to evaluate the mutagenic sensitivity of the L -arabinose forward mutation assay of S. typhimurium with respect to those types of mutagens. The mutagenicity of each compound was determined by liquid test, measuring both the frequency of mutants among the survivors and the absolute number of mutants growing in selective plates with traces of D -glucose. Strain BA13 with a wild-type lipopolysaccharide barrier was used as compared to the deep rough derivative strain BA9. The chemicals studied were: bleomycin, t-butyl hydroperoxide, chromium trioxide, cumeme hydroperoxide, formaldehyde, glyoxal, glutaraldehyde, hydrogen peroxide, paraquat, and phenylhydrazine. Additionally, ultrasonic oscillation was used as a presumable non-mutagenic lethal control treatment. The L -arabinose forward mutation assay detected the mutagenic activity of all the chemicals under study with a high degree of sensitivity, including paraquat which is unable to revert strain TA102. Positive responses were obtained at doses equivalent to or 10 times lower than the doses detected by strain TA102. The results support the idea that the L -arabinose forward mutation assay could replace the set of specific tester strains used by the histidine reverse mutation assay in general screening for genetic toxins.
54 citations
TL;DR: These antibodies were used to determine, by immunoelectron microscopy, the intracellular location of nitrate reductase in the aforementioned green algae, and in all cases, the enzyme was specifically located in the pyrenoid.
Abstract: Antibodies against nitrate reductase from Monoraphidium braunii have been used to determine the antigenic relationships of nitrate reductases from different green algae. Nitrate reductases from Chlamydomonas reinhardii, Chlorella fusca, Dunaliella salina , and Scenedesmus obliquus , were inhibited by, and cross-reacted with, antibodies raised against the enzyme from Monoraphidium braunii. These antibodies were also used to determine, by immunoelectron microscopy, the intracellular location of nitrate reductase in the aforementioned green algae. In all cases, the enzyme was specifically located in the pyrenoid.
49 citations
TL;DR: The thermal decomposition of these compounds was monitored by DTA and TG, and the resulting products have been studied by X-ray and IR techniques as discussed by the authors, showing that ammonium dawsonite and lithium hydrotalcite are less stable.
48 citations
TL;DR: This note shows that virtually all the multi-objective and goal-programming approaches can be thought of as special cases of a general distance-function model.
Abstract: This note shows that virtually all the multi-objective and goal-programming approaches can be thought of as special cases of a general distance-function model. Although the outcome of this paper cannot be considered completely new, it can, however, help increasing conceptual clarity and precision in future dialogue, showing the actual links between multi-objective programming, goal programming and traditional mathematical programming.
37 citations
TL;DR: The neonatal estrogenization produced the following reproductive changes prior to puberty: testis, adrenal, and ventral prostate atrophy; increase in the weights of seminal vesicles and epididymis; decrease in testosterone plasma levels; delayed balanopreputial separation; and abolition of luteinizing hormone response to orchidectomy.
Abstract: Intact Wistar male rats injected on Day 1 with 500 �g of estradiol benzoate or olive oil were decapitated on Days 15 and 22 or maintained until adulthood to analyze the balanopreputial separation. Other oil or estradiol-treated rats were orchidectoinized on Day 15 and decapitated on Day 22. The neonatal estrogenization produced the followingreproductive changes prior to puberty: 1) testis, adrenal, and ventral prostate atrophy; 2) increase in the weights of seminal vesicles and epididymis; 3) decrease in testosterone plasma levels; 4) delayed balanopreputial separation; 5) abolition of !uteinizing hormone response to orchidectomy; 6) transient increase in prolactin plasma levels; and 7) blockade in seminal and prostate response to orchidectomy.
37 citations
TL;DR: In this paper, the olefinic double bond of styrene (S) and α-methylstyrene (MS) was measured using methanol as the solvent in the temperature range 293-323 K over Rh AlPO 4 catalysts of different rhodium loading.
27 citations
TL;DR: Contrast two-dimensional echocardiography in the intraoperative evaluation of aortic and mitral regurgitation in 35 patients undergoing cardiac operations is suggested to be an important tool for the cardiac surgeon.
26 citations
TL;DR: In this paper, the authors determined the systematic errors introduced in the calculation of some kinetic parameters, such as Tafel slopes and reaction orders, on applying both the Butler-Volmer equation and the rate-determining step approximation at potentials corresponding to the foot of the polarographic waves.
TL;DR: A review is presented in which the fundamental principles, instrumentation and practical aspects of flow injection analysis (FIA) are discussed, with a particular focus on applications in pharmaceutical chemistry, which offers a wide scope to the new technique.
TL;DR: The hypothesis attributing the redox interconversion to formation/disappearance of an erroneous disulfide between one of the half-cystines located at the GSSG-binding site and another cysteine nearby is supported.
Abstract: 1
The changes undergone by pure yeast glutathione reductase during redox interconversion have been studied. Both the active and inactive forms of the enzyme had similar molecular masses, suggesting that the inactivation is probably due to intramolecular modification(s).
2
The glutathione reductase and transhydrogenase activities were similarly inactivated by NADPH and reactivated by GSH, while the diaphorase activity remained unaltered during redox interconversion of glutathione reductase. These results suggest that the inactivation site could be located far from the NADPH-binding site, although interfering with transhydrogenase activity, perhaps by conformational changes.
3
The inactivation of glutathione reductase by 0.2 mM NADPH at pH 8 was paralleled by a gradual decrease in the absorbance at 530 nm and a simultaneous increase in the absorbance at 445 nm, while the reactivation promoted by GSH was initially associated with reversal of these spectral changes. The inactive enzyme spectrum retained some absorbance between 500 nm and 700 nm, showing a shoulder at 580–600 nm. Upon treatment of the enzyme with NADPH at pH 6.5 the spectrum remained unchanged, while no redox inactivation was observed under these conditions. It is suggested that the redox inactivation could be associated with the disappearance of the charge-transfer complex between the proximal thiolate and oxidized FAD in the two-electron-reduced enzyme.
4
The inactive enzyme was reactivated by low GSSG concentrations, moderate dithiol concentrations, and high monothiol concentrations. These results and the spectral changes described above support the hypothesis attributing the redox interconversion to formation/disappearance of an erroneous disulfide between one of the half-cystines located at the GSSG-binding site and another cysteine nearby.
TL;DR: The intracellular location of nitrate reductase in green algae was examined by applying an immunocytochemical method to M. braunii cells and the enzyme was specifically located in the pyrenoid region of the chloroplast.
Abstract: Homogeneous nitrate reductase (EC 1.6.6.2) from Monoraphidium braunii was obtained by means of affinity chromatography in blue-Sepharose and gel filtration. After electrophoresis in polyacrylamide, gel slices containing pure nitrate reductase were disrupted and injected into previously unimmunized rabbits. The antiserum produced after several weeks was found to inhibit the different activities of nitrate reductase to a similar degree. Monospecificity of the antiserum was demonstrated by Ouchterlony double diffusion and crossed immunoelectrophoresis. The antibodies were purified by immunoabsorption to Sepharose-bound nitrate reductase. The intracellular location of nitrate reductase in green algae was examined by applying an immunocytochemical method to M. braunii cells. Ultrathin frozen sections were first treated with immunopurified anti-nitrate reductase monospecific antibodies, followed by incubation with colloidal gold-labeled goat antirabbit immunoglobulin G as a marker. The enzyme was specifically located in the pyrenoid region of the chloroplast.
TL;DR: The glutathione reductase from E. coli was rapidly inactivated following aerobic incubation of the pure and cell-free extract enzymes with NADPH, NADH and other reductants, and was reactivated by treatment with oxidized and reduced glutATHione, ferricyanide, and dithiothreitol in a time-and temperature-dependent process.
Abstract: The glutathione reductase from E. coli was rapidly inactivated following aerobic incubation of the pure and cell-free extract enzymes with NADPH, NADH and other reductants. The inactivation of the pure enzyme depended on the time and temperature of incubation (t1/2 = 2 min at 37°C), and was proportional to the |INADPH|/|enzyme| ratio, reaching 50% in the presence of 0.3 μM NADPH and 45 μM NADH respectively, at a subunit concentration of 20 nM. Higher pyridine nucleotide concentrations were required to inactivate the enzyme from cell-free extracts. Two apparent pKa, corresponding to pH 5.8 and 7.3, were determined for the redox inactivation. The enzyme remained inactive even after eliminating the excess NADPH by gel chromatography.
E. coli glutathione reductase was protected by oxidized and reduced glutathione against redox inactivation with both pure and cell-free extract enzymes. Ferricyanide and dithiothreitol protected only the pure enzyme, while NADP+ exclusively protected the cell-free extract enzyme. The inactive glutathione reductase was reactivated by treatment with oxidized and reduced glutathione, ferricyanide, and dithiothreitol in a time-and temperature-dependent process. The oxidized form of glutathione was more efficient and specific than the reduced form in the protection and reactivation of the pure enzyme. The molecular weight of the redox-inactivated E. coli glutathione reductase was similar to that of the dimeric native enzyme, ruling out aggregation as a possible cause of inactivation. A tentative model is discussed for the redox inactivation, involving the formation of an ‘erroneous’ disulfide bridge at the glutathione-binding site.
TL;DR: Anti-glutamine synthetase serum was raised in rabbits by injecting purified glutamine Synthetase (GS) of the phototrophic bacterium Rhodopseudomonas capsulata E1F1 with increased antigen levels, that were not found in the presence of glutamine or chloramphenicol.
Abstract: Anti-glutamine synthetase serum was raised in rabbits by injecting purified glutamine synthetase (GS) of the phototrophic bacterium Rhodopseudomonas capsulata E1F1. The antibodies were purified to monospecificity by immunoaffinity chromatography in GS-sepharose gel. These anti-GS antibodies were used to measure the antigen levels in crude extracts from bacteria, grown phototrophically with dinitrogen, nitrate, nitrite, ammonia, glutamate, glutamine or alanine as nitrogen sources. The amount of GS detected by rocket immunoelectrophoresis was proportional to Mn2+-dependent transferase activity measured in the crude extracts. Addition of GS inhibitor l-methionine-d,l-sulfoximine (MSX) to the actively growing cells promoted increased antigen levels, that were not found in the presence of glutamine or chloramphenicol. The ammonia-induced decrease in GS relative levels was reverted by MSX. GS levels remained constant when phototrophically growing cells were kept in the dark.
TL;DR: Ferredoxin from Chlamydomonas reinhardii has been purified to electrophoretic homogeneity by an easy and fast procedure with a high yield (25 -30 mg/250 g wet weight of cells) and an average molecular weight of 11800 was calculated from sedimentation coefficient, Stokes radius, and amino acid composition.
Abstract: Abstract Ferredoxin from Chlamydomonas reinhardii has been purified to electrophoretic homogeneity by an easy and fast procedure with a high yield (25 -30 mg/250 g wet weight of cells). An average molecular weight of 11800 was calculated from sedimentation coefficient (1.70 S) and Stokes radius (1.75 nm) data, sodium dodecyl sulfate-electrophoresis, and amino acid composition. Absorption spectrum show ed maxima at 276, 330, 420 and 460 nm in the oxidized form, with an absorption ratio (A420/A276) of 0.54 and an extinction coefficient of 8.38 mᴍ-1· cm -1 at 420 nm. R educed ferredoxin show ed a single peak at 276 nm with shoulders at 284, 310, 390, 469 and 537 nm and at liquid helium temperatures gave EPR signals at g = 1.877, 1.951 and 2.045. The protein has an isoelectric point of 3.30, and one (2Fe-2S)-cluster per molecule with a midpoint potential, at pH 7.5, of -410 mV (n=1) . The m olecule of C. reinhardii ferredoxin consists of 95-99 amino acid residues which includes the full com plement of amino acids, being alanine the most abundant.
TL;DR: In this paper, the i-t-E relations have been analyzed in differential pulse polarography (DPP) for processes in which a very fast dimerization preceded by a reversible electron transfer takes place.
TL;DR: Flow gradients controlled by a variable hydrostatic head have been employed in FIA for the first time and the potential of this technique for enhancing the applications of FIA is shown.
TL;DR: Results show that both in situ and in vivo the glutathione reductase of Escherichia coli is subjected to a redox interconversion mechanism probably controlled by the intracellular NADPH and GSSG concentrations.
Abstract: The redox interconversion of Escherichia coli glutathione reductase has been studied both in situ, with permeabilized cells treated with different reductants, and in vivo, with intact cells incubated with compounds known to alter their intracellular redox state.
TL;DR: In this article, a method for the determination of ethanol in blood based on the reaction was proposed. But this method is not suitable for the detection of ethanol due to high specifity and the need for no separation processes.
TL;DR: In this article, two methods for the determination of manganese iron in mixtures are suggested based on their catalytic action on the oxidation of salicylaldehyde thiosemicarbazone by hydrogen peroxide.
TL;DR: In this article, the polarographic reduction of mesityl oxide is used as an example of an electrodimerization process which does not fit the classical mechanism involving radical-radical dimerization in the reaction layer.
TL;DR: Several different configurations for simultaneous and sequential photometric speciation of Cr(VI and Cr(III) based on the reversed flow injection analysis and completely continuous modes are proposed in this article.
Abstract: Several different configurations for simultaneous and sequential photometric speciation of Cr(VI) and Cr(III) based on the reversed flow injection analysis and completely continuous modes are proposed in this paper. The determination of these species at theμg · ml−1 level is achieved with sampling frequencies between 30 and 100 h−1 and an r.s.d. of less than ±1% for simultaneous methods and of less than ±3% for the sequential method. The proposed methods are suitable for chromium speciation in waters. A simulation of the continuous monitoring of Cr(VI) and periodical of Cr(III) in natural and waste waters has been performed. The most frequent interferents in these types of samples have been investigated.
TL;DR: It is concluded that urate uptake in C. reinhardtii is an inducible energy-dependent mediated transport process different from the enzyme-catalyzed intracellular urate oxidation.
TL;DR: There was no correlation between the number of infused nucleated cells and granulocyte recovery and there were significant differences between the day of engraftment in patients with clinically documented HSV infection compared to patients without infection.
Abstract: The possible interrelation between infused bone marrow CFU-GM and peripheral granulocyte recovery was studied in 16 patients transplanted for acute leukemia. The influence of several clinical events that could modify the graft fate were also analysed. Our results show that: 1) There was no correlation between the number of infused nucleated cells and granulocyte recovery. 2) There was no correlation between the number of infused CFU-GM and granulocyte regeneration. 3) There were significant differences between the day of engraftment in patients with clinically documented HSV infection compared to patients without infection.
TL;DR: The kinetic determination of copper, cobalt and nickel in binary and ternary mixtures without prior separation is described and a combined initial-rate and fixed-time method is proposed here for the first time.
TL;DR: A new technique is presented for surgical correction of tricuspid atresia, univentricular heart, pulmonary atResia with intact ventricular septum and hypoplastic ventricle, and Hypoplastic left heart syndrome, and it is considered feasible for clinical application.
TL;DR: In this paper, a generalization of the chain-dependent process is proposed to describe daily rainfall, allowing probabilities of rain occurrence to depend on the amount of rain in the day before.
Abstract: A generalization of the chain-dependent process is proposed to describe daily rainfall. The model allows probabilities of rain occurrence to depend on the amount of rain in the day before. The influence of the antecedent amount of rain on the next day occurrence is called “feedback.” A method for identification of feedback effects in a series of observations is derived and application made to rainfall occurrence at Los Angeles. Performance of the model in reproducing other precipitation patterns, such as maximum daily rainfall or total amount of rainfall in successive n-day periods, was checked by the Monte Carlo method.