Showing papers by "National University of Cuyo published in 1970"
TL;DR: It is suggested that caerulein and caerulesin‐like polypeptides may have some function either in the regulation of secretory processes of the skin or in the exchange of water and electrolytes through the skin, or in both.
Abstract: 1. The South American amphibian Leptodactylus pentadactylus labyrinthicus and the South African amphibian Xenopus laevis contain in their skin a polypeptide indistinguishable from caerulein prepared from the Australian amphibian Hyla caerulea.
2. The caerulein content of different batches of Leptodactylus pentadactylus labyrinthicus skins varies from 10 to 500-600 μg/g tissue. Drying of the skin causes either a moderate decrease or a slight increase in the caerulein content. Methanol extraction gives considerably higher yields of caerulein than acetone extraction.
3. Caerulein or caerulein-like polypeptides also occur in the skin of several other species of Leptodactylus together with 5-hydroxyindole alkylamines and imidazole alkylamines. Yet other species of Leptodactylus lack caerulein-like polypeptides and 5-hydroxyindole alkylamines.
4. It is suggested that caerulein and caerulein-like polypeptides may have some function either in the regulation of secretory processes of the skin or in the exchange of water and electrolytes through the skin, or in both.
50 citations
TL;DR: Changes in endogenous gibberellin-like substances (GLS) have been studied in shoots and roots of potato plants grown under strictly controlled conditions (continuous light, short days and darkness, in combination with high and low temperature temperatures).
Abstract: L'evolution des substances de type gibberellines endogenes dans les tiges et les racines des plantes cultivees en conditions controlees, ainsi que les changements de substances de type anti-gibberellines chez le meme materiel a ete etudie.
34 citations
TL;DR: This paper describes, at the ultrastructural level, the changes which occur in the apical cytoplasm of the Sertoli cell from the beginning to the end of stage VIII of spermatogenesis.
34 citations
TL;DR: The results are discussed in the light of the action of gonodotropins on the Sertoli cell of amphibians and it is postulated that also in the hamster the phenomena of sperm release are under hormonal control.
32 citations
TL;DR: The only bird presenting endothelial granules showed that such bodies have a structure similar to that of the mammalian studied, and are the differences observed between the granules of lower and higher vertebrates representation for the evolutionary pattern of a subcellular body.
Abstract: The fine structure of the vascular endothelial cells was studied, with special reference to their dense granules, in seventeen species belonging to the five classes of vertebrates. The granules were spheric or ovoid, of high electronic density, and surrounded by a single three layered membrane. In the higher vertebrates the granules are less numerous and smaller (0.1–0.4 μ) than in the lower vertebrates (0.3–0.5 μ). Tubular structures were observed in the mammalian granules, while the granular content was homogenously dense in lower vertebrates. The only bird presenting endothelial granules showed that such bodies have a structure similar to that of the mammalian studied. Two questions arise 1) is the physiological function of these granules similar in different species; and 2) are the differences observed between the granules of lower and higher vertebrates representation for the evolutionary pattern of a subcellular body.
21 citations
TL;DR: The splanchnic nerves of toads were tightly ligated and the organelles present both on the proximal and the distal side of the constriction were counted and evidence is presented in support of the view that granulated vesicles are budded from swollen canaliculi.
Abstract: The splanchnic nerves of toads were tightly ligated and the organelles present both on the proximal and the distal side of the constriction were counted after zero, 24 and 48 hrs. Swelling of the fibers and accumulation of mitochondria and of smooth canaliculi were found to be the most conspicuous expressions of damming in the nerve segments above the constriction. No changes in the microtubule population or in the ratio of dense-core microtubules to empty microtubules were observed. A progressive collection of granulated vesicles is described for a minority of fibers in the segment proximal to the ligature. Evidence is presented in support of the view that such granulated vesicles are budded from swollen canaliculi. Fine structural expressions of damming were not found in the nerve segments distal to the constriction.
20 citations
TL;DR: The results indicate that the mitochondrion is the first and most responsive organelle affected by HCG treatment, and a hypothesis is advanced thatThe mitochondria of the Leydig cell provide the energy required for the lipolytic effect of HCG.
Abstract: Adult mice were treated daily with HCG (human chorionic gonadotropin). The most notable changes were found 24 hours after the second injection of 100 i.u. Nearly all lipid droplets had disappeared. Mitochondria showed a constriction linking the two portions of the organelle with widened intracristal spaces. Doughnut-shaped, bifurcated, and elongated mitochondria occurred commonly; their intracristal spaces were consistently widened. The Golgi complex was well developed. Dense bodies and phagolysosomes seemed to disappear.
16 citations
TL;DR: In this paper, it was shown that after a complete and partial removal of the median eminence, the axons leading from the dorsal group of neurons of the preoptic nucleus became hypertrophied, vacuolated and very deeply stained by the aldehyde fuchsin.
15 citations
TL;DR: The study of the fine structure of the vaginal mucosa reveals the presence of different types of cell junctions during all phases of the menstrual cycle, with desmosomes being the predominant type over the other two types.
14 citations
TL;DR: Bei männlichen Ratten nimmt bei kochsalzreicher Diät die Kininkonzentration im Plasma ab und normalisiert sich auf gemässigten Salzhaushalt.
Abstract: Bei mannlichen Ratten nimmt bei kochsalzreicher Diat die Kininkonzentration im Plasma ab und normalisiert sich auf gemassigten Salzhaushalt.
8 citations
TL;DR: Leptodactylus vilarsi, a rare Ecuadorian amphibian belonging to the “pachypus” section of the LeptodACTylus genus, contains in its skin a set of biogenic amines.
DOI•
01 Sep 1970TL;DR: In this paper, several deformation mechanisms are discussed which may be influenced by the stacking fault energy: forest cutting at the beginning of plastic deformation in fcc and hex metals, cross slip in fee metals, prismatic slip in hexagonal metals, and slip in bee metals.
Abstract: Several deformation mechanisms are discussed which may be influenced by the stacking fault energy: forest cutting at the beginning of plastic deformation in fcc and hex metals, cross slip in fee metals, prismatic slip in hexagonal metals, and slip in bee metals. Existing experimental data for the temperature and strain rate dependence of the shear stress at which the relevant deformation mechanism begins are analyzed. It is shown that the data for cross slip in fee metals, for prismatic slip, and for slip in bee metals can be described by an Arrhenius equation with an activation energy that is proportional to the logarithm of the stress. Stacking fault energies are determined from the strain rate sensitivity of the shear stress.
TL;DR: The stalk connecting each residual body to its spermatid, elongates to the point where it becomes severed at the moment when the sPermatid is pushed away toward the tubule lumen, according to the fluid current produced in the seminiferous tubules toward the rete testis.
Abstract: This study describes, at the ultrastructural level, the cytological mechanisms operative in spontaneous spermiation in the guinea pig. At the beginning of stage VII of the spermatogenic wave, the mature spermatids lodge their heads each in an apical recess of the sustentacular cell, progressive widening of the cisternae of smooth endoplasmic reticulum and a moderate swelling of the cytoplasmic matrix obliterate the apical recesses, and the spermatids are then pushed away toward the tubule lumen.
TL;DR: In this article, the EPR lineshifts for Gd 3+ : ThO 2 under uniaxial stress were measured for the second and fourth order spin lattice strain coefficients.
TL;DR: In this paper, the configuración of an espacio politico, in this case the Jurisdiccion de Mendoza, is studied, in the context of the Valle de Uco exposicion.
Abstract: En este trabajo buscamos observar en que medida la configuracion de un espacio politico, en este caso Valle de Uco (jurisdiccion de Mendoza), estuvo atravesada al menos por dos tramas de variables. Por un lado, la visibilizacion de una serie de circuitos mercantiles en el sur de Mendoza que articulaban las zonas de frontera, aun mas alla de las no dominadas por los hispanocriollos, y con los pasos cordilleranos de esa zona. Por otro lado, el “problema” de la criminalidad en ciertas coyunturas politico-militares que generaban una movilidad notable de poblacion y un flujo mas intenso de productos, pero que tambien servia como argumento para justificar politicas de control creciente sobre los espacios rurales. En este sentido, la exposicion estara organizada en dos apartados. En el primero intentaremos mostrar como con la Revolucion se consolidaron oficialmente circuitos mercantiles que tenian larga tradicion colonial y adquirieron luego de 1820 mayor visibilidad para los gobiernos. En el segundo, analizaremos de que modo, si bien los ataques contra la propiedad pudieron haber aumentado en ciertas coyunturas, su creciente criminalizacion y punicion quiza se profundizo al ritmo de la consolidacion de una burocracia estatal provincial que necesitaba garantizar la seguridad de la propiedad privada y la publica en los espacios de trafico mercantil y produccion ganadera.
TL;DR: In this article, the electrical magnetoresistivity of high purity Indium at low temperatures has been investigated and it was shown that a generalized Kohler's rule can be used to describe all experiments and a reliable method was obtained for extrapolating the zero magnetic field resistivity to temperatures below the superconducting transition temperature.
TL;DR: A red impurity (dye C, absorption maximum 560 mμ) was separated from two commercial samples of trypan blue by dialysis against double-distilled water and ethanol extraction as mentioned in this paper.
Abstract: A red impurity (dye C, absorption maximum 560 mμ) was separated from two commercial samples of trypan blue by dialysis against double-distilled water and ethanol extraction. Paper and Sephadex G-25 chromatography proved that the nondiffusable trypan blue (TBC) was made up of 85% blue dye (dye TB, absorption maximum 590 mμ) and of residual dye C (15%). Swiss mice were injected ip on day 8 of pregnancy with 2–3 mg of TBC or with dye C in an amount representing 15% of the absorbance units (at 590 mμ) of the whole dose of TBC. All were killed on day 16 of pregnancy. The conceptuses of females treated with dye TBC were 62% resorbed, and 29% of the survivors were malformed. Those of the dye C group were 4% resorbed and 17% malformed. Only one of the 73 control implants was resorbed. The mean weight of both experimental groups was significantly lower than that of controls. The malformations were, in order of frequency: omphalocele, encephalocele, exencephaly, monophthalmus and anophthalmus. The types and distribution of malformations obtained with dye C were similar to those caused by the nondiffusable dye.
TL;DR: Normal as well as hyperthyroid patients showed significant changes in unsaturated iron-binding capacity and percentage iron saturation after oral ferrous gluconate overloading, when the mean fasting values were compared with the values obtained 2, 4, and 6 hr. following ingestion of the iron.
Abstract: This study deals with the effects of altitude and hyperthyroidism on iron metabolism as measured by total ironbinding capacity, unsaturated iron-binding capacity, percentage iron saturation, and siderophilin determinations in patients who were fasting and who then ingested overloads of oral iron as ferrous gluconate (176 mg.). Neither altitude nor hyperthyroidism had a demonstrable effect on the values listed above; however, normal as well as hyperthyroid patients showed significant changes in unsaturated iron-binding capacity and percentage iron saturation after oral ferrous gluconate overloading, when the mean fasting values were compared with the values obtained 2, 4, and 6 hr. following ingestion of the iron.
TL;DR: Mendoza province in western Argentina has been known for centuries as a focus of moderately severe endemic goiter, but there has been a dramatic decrease in the incidence of goiter in the province as a result of the prophylaxis program.
TL;DR: In this article, a description of the dynamics of crystals by means of collective variables, namely the Fourier transforms of the divergence and curl of the current, is given, and a relationship between frequency and wave number is derived for the excitations of the system from them.
Abstract: A description is given of the dynamics of crystals by means of collective variables, namely the Fourier transforms of the divergence and curl of the current It is shown that, in the harmonic approximation, the classical equations of motion are reduced to a set of three equations involving only the collective variables themselves From these equations the usual result for the frequency of phonons is obtained Furthermore, the quantum-mechanical equations of motion can again be reduced, in a suitable approximation, to a set of three coupled equations in the collective variables A relationship between frequency and wave number is derived for the excitations of the system from them