Showing papers by "University of Buenos Aires published in 1982"
TL;DR: Two effects of stress on pollen availability were distinguished: a reduction in the duration of exposure of silks of the apical ear to pollen, and a fall in the rate of pollen production during the period in which receptive silks were present.
174 citations
125 citations
TL;DR: Thirty-three eyes of 18 normal infants and children and 36 eyes of infants in whom congenital glaucoma had been diagnosed were measured by echometry, finding the anterior chamber depth, vitreous length, and axial length were notably greater inglaucomatous eyes, while the lens thickness was smaller in glaucolysis.
Abstract: Thirty-three eyes of 18 normal infants and children and 22 eyes of 15 infants and children in whom congenital glaucoma had been diagnosed were measured by echometry. The anterior chamber depth, vitreous length and axial length were significantly greater in glaucomatous eyes, while the lens thickness was smaller in glaucomatous eyes. The axial length of normal eyes was found to increase with age according to the equation: axial length = 18.7 + 2.245 log (age in months.) The confidence interval of the normal growth curve allows the prediction of the maximum normal axial length for any given age. In congenital glaucoma cases, in which the visual fields and daily pressure curve cannot be evaluated, clinical echometry is proposed as a very valuable diagnostic and follow-up procedure.
110 citations
TL;DR: Benznidazole (a nitroimidazoles derivative used for the treatment of Chagas' disease) is reduced by rat liver microsomes to the nitro anion radical, as indicated by ESR spectroscopy.
98 citations
TL;DR: Proteolipids from adult rat brain subcellular fractions were purified by a one-step procedure involving chromatography through Sephadex LH-60 eluted with an acidified chloroform-methanol mixture, indicating that the proteolipid apoproteins purified by this method do not adsorb hydrophobic low-molecular-weight compounds.
68 citations
TL;DR: This paper argued that three main elements form the basis of both the Latin American and the European branches of the structuralist school of inflation theory: relative prices that change when economic structure changes; downward inflexibility of (some) money prices; and a passive money supply closing the deflationary gap caused by price increases.
58 citations
TL;DR: In this paper, a compilation of water activity values for fresh foods namely fruits, vegetables and meats was presented, where water activities were calculated from reported data on the cryoscopic temperature (or initial freezing point) of fruits and vegetables.
Abstract: This work presents a compilation of water activity (aw) values for fresh foods namely fruits, vegetables and meats. Water activities were calculated from reported data on the cryoscopic temperature (or initial freezing point) of fruits, vegetables and meats, amounting to eighty six different items. In practically all cases studied the water activity is in the range 0.970–0.996.
55 citations
TL;DR: The results indicate that PEPCK and ME are present in different subcellular compartments, a fact significant for the prevention of a futile cycle between C4-dicarboxylic acids and C3-monocarboxYlic acids, which might take place if both enzymes functioned in the same compartment.
51 citations
TL;DR: Normal BALB/c mice injected with I-RNA acquired the capacity to respond to the specific antigen as measured by leukocyte migration inhibition reaction, and induced a secondary antibody response.
34 citations
TL;DR: The results suggest that the microtubular system is involved in the transport of proteolipid proteins from their sites of synthesis to their site of deposition and that the various types of myelin proteins follow different transport routes to enter into this special type of membrane.
Abstract: Brain slices from 20 day old rats were incubated with radioactive aminoacids in the presence and absence of 500 μM colchicine and the appearance of labeled proteins in myelin and in a myelin-like fraction (SN4 fraction) was measured. In the presence of the inhibitor, the entry of proteolipid proteins was decreased to 55% in myelin and to 45% in SN4 fraction with reference to control values while the entry of basic proteins and other minor protein components was unaffected in both fractions. The synthesis of proteolipid proteins was not affected by the presence of colchicine; moreover, a slight accumulation of these proteins was observed in microsomes. The results suggest that the microtubular system is involved in the transport of proteolipid proteins from their site of synthesis to their site of deposition and that the various types of myelin proteins follow different transport routes to enter into this special type of membrane.
32 citations
TL;DR: A preparation enriched in basement membranes from seminiferous tubules was isolated from rat testes and injected with complete Freund's adjuvant into Wistar rats, and in 60% of animals a mild multifocal orchitis was observed.
TL;DR: In the streptozotocin-injected rats, the variation of HBD activity and the modification of the mitochondrial oscillation pattern were time-dependent phenomena, both effects reaching their maximal expression about 1 month after the onset of diabetes.
01 Jan 1982
TL;DR: Two major events characterize the development of legal philosophy in the decade 1966-1976: 1) the increasing interest of legal theorists in deontic logic and subsequent attempts to capitalize upon the insights achieved by deontics for the clarification of legal reasoning and the analysis of legal concepts; and 2) the powerful attack launched by Ronald Dworkin against the hitherto prevailing trend in legal philosophy, viz. legal positivism as mentioned in this paper.
Abstract: Two major events characterize the development of legal philosophy in the decade 1966–1976: first, the increasing interest of legal theorists in deontic logic and the subsequent attempts to capitalize upon the insights achieved by deontic logicians for the clarification of legal reasoning and the analysis of legal concepts;1 second, the powerful attack launched by Ronald Dworkin against the hitherto prevailing trend in legal philosophy, viz. legal positivism.
TL;DR: Experimental results suggest that the Ca2+ - p- nitrophenylphosphatase activity depends on ATP at the high-affinity site and PNPP is hydrolyzed at the low-Affinity site, and Ca2- -ATPase activity at theHighaffinity size persists during Ca2+, and both phenomena take place with the same apparent affinity and along curves of the same shape.
TL;DR: It is indicated that ethanol can alter prolactin secretion and the synthesis of GABA in the hypothalamus and the effect of ethanol on the activity of glutamic acid decarboxylase inThe hypothalamus is examined.
Abstract: The effect of acute and chronic administration of ethanol on prolactin secretion in male rats was investigated under basal conditions and after the administration of sulpiride. The effect of ethanol on the activity of glutamic acid decarboxylase (GAD) in the hypothalamus was also examined. Acute administration of ethanol significantly increased serum prolactin levels. This increase persisted after sulpiride administration. In contrast, chronic administration of ethanol did not significantly modify serum prolactin levels. However, the elevation of prolactin levels in response to the injection of sulpiride was significantly lower in rats chronically treated with ethanol than in control animals. Pituitary concentration of prolactin was not significantly modified by acute or chronic administration of ethanol. Sulpiride administration failed to reduce the concentration of prolactin in the pituitary of rats acutely treated with ethanol, in contrast to its effect in control rats. Acute administration of ethanol significantly decreased hypothalamic GAD activity, while chronic ethanol treatment caused an increase in GAD activity in the hypothalamus. These results indicate that ethanol can alter prolactin secretion and the synthesis of GABA in the hypothalamus.
TL;DR: Treatment of the synaptic membranes with Triton X-100 enhanced [ 3 H]GABA binding depending on the developmental stage studied, suggesting that GABAmodulin that inhibits the binding also appears during that period.
TL;DR: Biliverdin reductase from normal rat liver was separated into two forms by DEAE-cellulose and the major peak 1 dissappeared and was replaced by a new major form (peak 3) which reduced biliverdin-IXβ at the highest rate and biliverin-IXα at a slightly lower rate.
TL;DR: Comparison of the experimental results with theoretical kinetic equations seems to indicate that the behavior of the system is in some respects difficult to reconcile with the predictions of the currently held view about the role of Na+, K+, M g + , and ATP during hydrolysis of ATP by the (Na,K]-ATPase.
Abstract: Since the initial observations by Post and coworkers,’ a large amount of information has accumulated indicating that hydrolysis of ATP by the (Na,K)ATPase proceeds through a series of steps involving the formation and hydrolysis of pho~phoenzymes.~-~ This information has led to a detailed reaction scheme for the hydrolysis of ATP and for the associated active transport of Na+ and K+.2.3 The main experimental support for the currently accepted reaction scheme comes from studies on partial reactions. Few attempts have been made to see to what extent this scheme is able to predict quantitatively the steady-state kinetic behavior of the (Na,K)-ATPase. Studies of this kind are important since agreement between theoretical predictions and experimental results is one of the necessary requirements for the validity of any reaction scheme. We will report here experiments on the interaction of ATP, K+, Na+, and M&+ with the (Na,K)-ATPase during steady-state ATP hydrolysis. We will try to show that comparison of the experimental results with theoretical kinetic equations seems to indicate that the behavior of the system is in some respects difficult to reconcile with the predictions of the currently held view about the role of Na+, K+, M g + , and ATP during hydrolysis of ATP by the (Na,K]-ATPase. The experiments reported here were performed using a partially purified (Na,K)-ATPase isolated from the outer medulla of dog kidney following Jdrgensen’s procedure “C.”4 ATPase activity was estimated from the initial rate of release of 32P (Pi) from [y-3ZP]ATP.5 Incubations were carried out at 37OC, adjusting the length of incubation and the concentration of enzyme so that no more than 10% of the ATP underwent enzymatic hydrolysis. In all media, pH was kept at 7.4 with 20 mM imidazol-HC1 and total salt concentration at 150 mM by mixing adequate amounts of NaCl, KCI, and choline C1. All media contained 1% (w/v] of bovine serum albumin.
TL;DR: The results demonstrate that in the pyramidal cells of CA3 there is a high concentration of postsynaptic muscarinic receptors and suggests the possible existence of a small population of presynaptic receptors that, hitherto, had only been demonstrated indirectly by physiological methods.
Journal Article•
01 Jan 1982
TL;DR: It is concluded that the striatum is the target area for the central effect of L-DOPA on salivary secretion, by activation of pathways descending through the fields of Forel and mesencephalic reticular formation to the contralateral lower brain stem.
TL;DR: Three purified human IgG antibodies against Trypanosoma cruzi showed different reactivities in vitro, and the ability to neutralize mice bloodstream trypomastigotes was analyzed, the results obtained indicated that anti-F antibody was the most effective.
TL;DR: It was concluded that the normal rat liver is prepared to dispose of exogenously added hemins by their oxidation toalpha-biliverdins, reduction of the latter to the corresponding alpha-bilirubin and excretion of their conjugated derivatives through the bile duct.
TL;DR: The interest of a group of specialists in this pathology notably improves early detection, and the CIS vulvar patients are generally younger than those suffering invasive cancer.
TL;DR: The results above presented show that the sensitivity of the submaxillary salivary glands of rats to some adrenergic and cholinergic drugs was altered by the thyroid hormone, which was greater in the responses mediated by beta receptors.
Abstract: The effect of changes in thyroid function on the action of autonomic drugs upon the secretion of saliva by the submaxillary glands was studied in male Wistar rats. Hyperthyroidism was induced by the sc administration every 12 h of 10 micrograms/100 g bw of L-triiodothyronine; hypothyroidism was induced by surgical thyroidectomy 2 weeks before the experiments. The dose-response curves to increasing doses of isoprenaline, norepinephrine or methacholine showed in hyperthyroid animals increased salivary secretion, while in hypothyroid animals the dose-response to the drug was reduced. The threshold dose for isoprenaline was reduced in hyperthyroid animals and increased in hypothyroid ones. The threshold dose for norepinephrine did not change in hyperthyroid or hypothyroid animals while that for metacholine was decreased in hyperthyroid ones. When norepinephrine was given to alpha-blocked animals (with phentolamine) the difference in the dose-response curves between hyperthyroid and control animals was increased. But when norepinephrine was given to beta-blocked animals (with propranolol) the difference between the dose-response curves of hyperthyroid and control animals disappeared. The results above presented show that the sensitivity of the submaxillary salivary glands of rats to some adrenergic and cholinergic drugs was altered by the thyroid hormone. The effect was greater in the responses mediated by beta receptors. The structural changes in these glands may have some role in these effects.
TL;DR: The findings suggest the presence of specific insulin binding sites in liver, adipose tissue, pituitary, and adrenal glands from turtles, consistent with the intracellular receptor mediated degradation hypothesis.
TL;DR: The electrophoretic pattern of microsomal proteolipid proteins did not show the high molecular weight components (aggregates of PLP) which are found in myelin, indicating that it might not be an exclusive component of myelin.
01 Jan 1982
TL;DR: The effect of cyclophosphamide (CY) on antibody dependent cell-mediated cytotoxic activity of murine splenic cells was evaluated and the possibility that CY eliminates a suppressor cell subpopulation that normally regulates ADCC levels is discussed.
Abstract: The effect of cyclophosphamide (CY) on antibody dependent cell-mediated cytotoxicity (ADCC) was evaluated. The results indicated that a single injection of CY markedly increased ADCC activity of murine splenic cells. This effect was dose dependent and was maximal on day 7 after the drug injection. The number of lymphoid cells in treated mice decreased to approximatedly 50%; however the percentages of EA rosettes were similar to those of control animals suggesting that the augmented cytotoxic activity was not due to a relative increase in Fc receptor bearing cells. CY treatment also enhanced delayed type hypersensitivity, but suppressed antibody production to sheep red blood cells. The possibility that CY eliminates a suppressor cell subpopulation that normally regulates ADCC levels is discussed.
TL;DR: The results indicate that cations do not follow the independence principle and behave as in single-file diffusion multi-ion pores when crossing the paracellular cation channels of Bufo arenarum gallbladder epithelium.
Abstract: The transepithelial fluxes, conductances and permeabilities of Li+, Na+, K+, Cs+, NH
4
+
and H3CNH
3
+
were studied under ionic concentrations ranging from 12 to 250mm inBufo arenarum gallbladders. When these measurements are carefully corrected in order to get only the component due to the paracellular cation channels, the following results are obtained: (1) The permeability ratios (cationic/anionic) are a decreasing function of salt concentration. (2) The partial conductances through paracellular cationic channels show nonlinear saturable concentration kinetics. (3) Moreover, partial conductance kinetics of K+, Cs+ and NH
4
+
present a maximum followed, at higher concentratons, by a negative-slope region. (4) The selectivity sequences obtained from biionic potentials do not agree with those obtained from partial conductance measurements. (5) The unidirectional22Na tracer flux (serosal to mucosal) is inhibited by 63% when the K+ symmetrical concentration in the bathing solutions is raised from 25 to 200mm. (6) When the unidirectional42K fluxes (serosal to mucosal) at 200mm KCl Na-free solutions are compared with K+ partial conductance by means of the Hodgkin and Keynes (Hodgkin, A.L., Keynes, R.D. 1955.J. Physiol London
128:61–88) expression, then′ factor is 2.0. These results indicate that cations do not follow the independence principle and behave as in single-file diffusion multi-ion pores when crossing the paracellular cation channels ofBufo arenarum gallbladder epithelium.