Showing papers by "University of Buenos Aires published in 1983"
TL;DR: The results are consistent with a peroxidative stress in chronic alcoholism leading to increased lipoperoxidation and decreased levels of antioxidants.
217 citations
TL;DR: Results show that branching of grasses is controlled by phytochrome activity in a way similar to that in dicotyledon plants.
Abstract: Variations in phytochrome status in grasses were provoked by end of day red and far-red treatments and above canopy irradiations. Lolium perenne L. and Lolium multiflorum Lam. plants developed more tillers when illuminated with higher red/far-red ratios. These results show that branching of grasses is controlled by phytochrome activity in a way similar to that in dicotyledon plants.
206 citations
TL;DR: The results are discussed in relation to some contradictory findings in the literature and to the fact that the hippocampal formation is related to neural mechanisms underlying behavior and neuroendocrine regulation.
123 citations
TL;DR: The dynamics of leaf chlorophyll level, nitrogen content, photosynthesis and stomatal conductance were followed in detail in two cultivars of maize during a short period of water stress, applied at tasseling, and during the subsequent recovery phase, and it was concluded that the stress-induced loss ofchlorophyll is not mediated by a lack of nitrogen.
Abstract: The dynamics of leaf chlorophyll level, nitrogen content, photosynthesis and stomatal conductance were followed in detail in two cultivars of maize (Zea mays) during a short period of water stress, applied at tasseling, and during the subsequent recovery phase. Plants used in the experiment were grown in sand-nutrient solution culture under field weather conditions. Water stress reduced chlorophyll levels, stomatal conductance and photosynthesis, but the nitrogen content of the leaves was not affected. It is concluded that the stress-induced loss of chlorophyll is not mediated by a lack of nitrogen. Considerable differences were observed between genotypes in the rate of post-stress recovery of chlorophyll level. Recovery, upon rewatering, of stomatal conductance and photosynthesis preceded that of chlorophyll level. Losses of up to 40% of leaf chlorophyll content were insufficient to affect rates of photosynthesis measured at mid-day.
75 citations
TL;DR: Gentian violet was found to undergo a one-electron reduction to produce a carbon-centered free radical, which may be the basic cause of the selective toxicity of gentian violet to Trypanosoma cruzi.
Abstract: Transmission of Chagas' disease by transfusion of blood containing Trypanosoma cruzi has often been reported, and gentian violet, a triarylmethane dye, is widely used by blood banks in attempts to eliminate such transmission. In a study of intact trypanosomes, gentian violet was found to undergo a one-electron reduction to produce a carbon-centered free radical as demonstrated by electron spin resonance spectroscopy. Either reduced nicotinamide adenine dinucleotide or the reduced dinucleotide phosphate could serve as a source of reducing equivalents for the production of this free radical by homogenates of Trypanosoma cruzi. The formation of this free radical, and the trypanocidal action of gentian violet, were enhanced by light. The enhanced free radical formation may be the basic cause of the selective toxicity of gentian violet to Trypanosoma cruzi.
73 citations
01 Jan 1983
TL;DR: The Molecular Biology of Growth Hormone (MBH) as discussed by the authors is a well-known growth hormone that has been shown to be useful in many applications in the field of biology.
Abstract: (1983). Molecular Biology of Growth Hormone. Critical Reviews in Biochemistry: Vol. 15, No. 1, pp. 25-56.
72 citations
TL;DR: In rats submitted to acute stress by forced swimming there was an immediate sharp decline in the binding of [3H]flunitrazepam and of [ 3H]ethyl-beta-carboline-3-carboxylate in synaptosomal membranes of the cerebral cortex and hippocampus, followed by a rebound increase in benzodiazepine receptors after 60 min, specially in the hippocampal formation.
63 citations
TL;DR: Palaeomagnetic and sedimentological studies carried out on the bottom sediments from three lakes in western Argentina are described in this paper, where the inter-lake correlation was derived from the inclination and declination patterns considered as a pair, also taking account of a set of radiocarbon age determinations.
Abstract: Summary.
Palaeomagnetic and sedimentological studies carried out on the bottom sediments from three lakes in western Argentina are described. At the within-lake level, five lithological units could be broadly defined and were useful as a general guide in defining detailed correlations based on the magnetic susceptibility (k) and intensity of remanent magnetization (J). In one of the three lakes, el Trebol, it was possible to derive a closer, lithologically based, correlation and this was consistent with that based on the magnetic parameters. Inter-lake correlation was derived from the inclination and declination patterns considered as a pair, also taking account of a set of radiocarbon age determinations to remove any ambiguities. All the individual measurements were transformed to a time-scale prior to stacking to produce type-curves. The records for Laguna el Trebol and Brazo de Campanario extend back to about 6000 radiocarbon years before present while Lago Morenito provides a record extending back to about 14000 radiocarbon years before present. The records exhibit variations with similar overall characteristics to those previously obtained for Europe and North America, but there appears to be no correlation with the northern hemisphere patterns on a swing to swing basis. Both clockwise and anticlockwise precession of the geomagnetic vector is evident both from spectral analysis of declination/inclination pairs and VGP paths.
59 citations
TL;DR: The results suggest that neurogenic hypertension is produced after the removal of NE tonic depressor activity in the anterior hypothalamus and that serotonergic mechanisms play a major role in the development of the increased arterial blood pressure in this preparation.
48 citations
TL;DR: Findings suggest that the tested glass ionomer might adequately replace the zinc phosphate cement as a luting material for endodontic implant stabilizers.
45 citations
TL;DR: A patient with types A and B of Wolff-Parkinson-White syndrome developed subacute pneumonitis during long-term treatment with amiodarone when the maintenance dose was increased to 800 mg/day.
TL;DR: Salivary flow-rate, pH of saliva and dental plaque, total concentrations of salivary proteins, inorganic phosphate, bicarbonate, calcium and amylase, as well as the proportional nutrient and calorie distribution of the foods were determined and compared with those of the previous habitual diet.
TL;DR: The immediate post-trial injection of the centrally active muscarinic agonist oxotremorine can facilitate the retention of a passiveavoidance response in mice, as indicated by performance on a retention test 24 h later, and it is probable that haloperidol pretreatment impaired oxot Remorine-induced memory facilitation.
Abstract: The immediate post-trial injection of the centrally active muscarinic agonist oxotremorine (0.025, 0.050 and 0.100 mg/kg, IP) can facilitate the retention of a passiveavoidance response in mice, as indicated by performance on a retention test 24 h later. Injections given 10 min after training also significantly facilitated retention, but given 120 min after training did not affect retention. These findings suggest an action of oxotremorine on memory mechanisms. The enhanced retention was neither the result of a punishing effect of oxtremorine nor of a nonspecific proactive pharmacological action of the drug.
TL;DR: Stereotactic injection of acetylcholine into the lateral septal region of the rat brain produces a long-lasting sympathetic-mediated increase of the arterial blood pressure, mediated by muscarinic receptors since 1 microgram atropine abolishes this response.
TL;DR: K+, Rb+ or Na+ increase from 30 to 90% the maximum rate of Ca2+ transport from resealed ghosts, leaving unaltered the apparent affinity of theCa2+ pump for Ca2+.
TL;DR: The extra GSH release in the nifurtimox-treated rats may indicate an alteration of the hepatocyte membrane, indicating that, in addition to the GSH-peroxidase reaction (resulting in GSSG generation), other glutathione-related processes were involved in nifutimox detoxification.
TL;DR: Administration of 4 mg/kg per day of diazepam in the drinking water for 14 days produced a small, but not significant decrease of benzodiazepine binding sites for [3H]flunitrazepam and [ 3H]ethyl-beta-carboline-3-carboxylate.
TL;DR: The results presented in this paper strongly suggest that esterification of PLP takes place in the myelin membrane or at a site very close to it.
TL;DR: In this paper, biochemical and electron spin resonance spectroscopic evidence was provided that contract of human polymorphonuclear leukocytes with antibody-coated Trypanosoma cruzi triggers the respiratory burst.
TL;DR: A central role for SRS-A in this reaction is suggested and it is suggested that increased isometric developed tension (IDT) and higher frequency of contractions were observed shortly after contact of PHA-activated lymphocytes with spontaneously beating rat atria.
Abstract: The effect of phytohemagglutinin (PHA) stimulated human lymphocytes on the contractile activity of isolated rat atria was studied. Increased isometric developed tension (IDT) and higher frequency of contractions (FC) were observed shortly after contact of PHA-activated lymphocytes with spontaneously beating rat atria. Since pre-exposure of the lymphocytes to PHA was not necessary and the pharmacologic effects were demonstrated immediately after addition of the lectin, division of the effector cells as a requisite for their action was excluded.
TL;DR: The results of this investigation support the possibility of the existence of a relationship between GABA-related enzymes in the hypothalamus and circulating prolactin levels.
TL;DR: In this paper, it was shown that a monad is finitary if its functor part is conservatiae if it reflects isomorphisms, and is fznitary if it preserves filtered colimits.
TL;DR: Biliverdin reductase from rat spleen and kidney exists only in molecular form 1 and is not transformed into molecular form 3 by either CoCl2 or phenylhydrazine treatments.
TL;DR: To determine the prevalence of inapparent infection with Junin virus among the rural population and its relation to the clinical disease, a serological study was carried out in two zones of the endemic area of Argentine hemorrhagic fever.
Abstract: To determine the prevalence of inapparent infection with Junin virus among the rural population and its relation to the clinical disease, a serological study was carried out in two zones of the endemic area of Argentine hemorrhagic fever (AHF). From the first appearance of AHF in the zones (1963) and the moment of the survey (1977), 14 years had passed. A total of 695 serum samples were obtained, 540 from Cordoba and 155 from Buenos Aires. Of the 695 serum samples, 83 were positive for neutralizing antibodies against Junin virus. Total infection (clinical and inapparent cases) reached 11.6% and 12.03% in the Buenos Aires and Cordoba zones, respectively, showing that the total prevalence of infection in two zones separated by 320 miles, are very much alike. In Cordoba province, the prevalence of clinical infection was 7.59%, while that for inapparent infection was 4.44%. Values for the Province of Buenos Aires were 9.67% and 1.93%, respectively.
In addition to a low prevalence of inapparent infections, the results of this survey show that roughly 90% of the population is susceptible to contract the disease; this stresses the need to immunize susceptible individuals in the endemic area.
TL;DR: Inner projections of the polarization propagator are used to calculate components of the Fermi contact interaction between protons attached to the bridgehead carbon atoms of bicyclo(2,2,1)Heptane four-and five-bond paths and throuh-space interaction are considered.
TL;DR: The extended half-life of this new agent (about 20 hours in cardiac patients) may allow a convenient twice-daily dosage schedule, and side effects were trivial.
TL;DR: The results support the view that MESNA, given orally in conjunction with combined cytostatic regimens which include IF, simplifies the treatment and provides optimum protection for the urinary epithelium.
TL;DR: By immunolabeling of the glial fibrillary acidic protein (GFAP) by the PAP method, a severe glial response could be seen in infected mice, featuring hyperplasia, hypertrophy, and shape distortion of the astrocytes, which suggests the accelerated maturation of the Astrocytes and the increased GFAP synthesis by direct action of the virus upon such cells.
Abstract: Intracerebral inoculation of strain XJ Clon 3 of Junin virus into 1–2-day-old mice resulted in the appearance of viral antigen, detectable by means of the peroxidase antiperoxidase (PAP) technique, within the cytoplasm of the neurons of the cerebral cortex, the basal nuclei, cerebellum, pons, medulla, spinal cord, and spinal ganglia; Junin antigen was likewise observed, although to a lesser extent, in the cytoplasm of astrocytes. The viral antigen was found in highest concentration at the cytoplasmic periphery, near the cell membrane, where complete virions are formed by budding. In some cells a “tigroid” distribution of the antigen was observed, suggestive of its production and concentration within the granular endoplasmic reticulum. In spite of the heavy infection of the neural structures, the neurons did not always show major alterations.