Showing papers by "Laval University published in 1975"
TL;DR: The frequency of congenital hypothyroidism is about one in 7,000 births and the immunoassay is effective in detecting thyroid hormone abnormalities with an acceptable percentage of false positive measurements; no false negative results have occurred.
319 citations
TL;DR: Growth hormone-release-inhibiting hormone (somatostatin) was localized in the external zone of the median eminence, the subcommissural organ, the organum vasculosum of the lamina terminalis and the pineal gland.
Abstract: Utilizing an immunoperoxidase technique at the light microscope level, growth hormone-release-inhibiting hormone (somatostatin) was localized in the external zone of the median eminence, the subcommissural organ, the organum vasculosum of the lamina terminal is and the pineal gland. No positive reaction was detected in any other brain area.
101 citations
TL;DR: The difference in emission peak maxima between the dopa and NA fluorophores and the DA fluorophore indicates a very attractive possibility of differentiation between these compounds directly in the fluorescence microscope by a readily distinguishable difference in color.
Abstract: tinction between, closely related fluorogenic compounds at the cellular level. Furthermore, the difference in emission peak maxima between the dopa and NA fluorophores and the DA fluorophore indicates a very attractive possibility of differentiation between these compounds directly in the fluorescence microscope by a readily distinguishable difference in color. These new principles are presently being applied to tissue for differentiation between intracellular dopa, DA and NA.
86 citations
TL;DR: In the postsynaptic dendrite or dendritic spine, a filamentous network was observed to be attached to the subsynaptic web by means of the E-PTA stain and of the HMM-labeling procedure, and a network consisting of actin-like filaments was demonstrated in the presynaptic bag.
Abstract: To identify structures involved in the translocation of the synaptic vesicles towards the presynaptic membrane, an ultrastructural study has been undertaken by means of (1) the E-PTA stain and (2) the HMM-labeling procedure. Using serial sections of E-PTA stained nervous tissue, especially those made in transversal and tangential planes, the geometric order of the presynaptic grid and of its constituents has been described in detail It consisted of dense projections having the shape of small truncated pyramids cut parallel to their hexagonal bases which rested on the electron-lucent presynaptic membrane. The dense projections were arranged at the points of equilateral triangles. Around each dense projection, six asymmetric hexagonal holes were seen to be arrayed in an hexagonal pattern, forming thus the presynaptic sieve. From the spiny tops of the dense projections, which appeared as specialized structures of the dense material coating the inner surface of the plasma membrane at the level of the synaptic cleft, fine filaments, 40–60 A in diameter, radiated and formed a three-dimensional meshwork pervading the presynaptic bag. The dense cytoplasmic coating delineating the plasma membrane served as anchor points for these microfilaments. Upon incubation with rabbit skeletal muscle HMM the microfilaments underwent specific structural changes, consisting of: (1) a striking increase in diameter; (2) the association of periodic and polarized substructures with their surfaces. The synaptic vesicles and mitochondria were seen to be attached to the numerous HMM-decorated filaments or enmeshed in the network formed by these filaments. The actin-like filaments were anchored to the plasma membrane at many points and to the presynaptic dense projections. Following incubation in the buffer alone or in buffered HMM solutions containing Na+ pyrophosphate or ATP, no arrowheaded structures were observed. Thus, a network consisting of actin-like filaments was demonstrated in the presynaptic bag. Of particular interest was the structural relation of the actin-like filaments with the occasional, tapered myosin-like filaments. The role of the presynaptic actin-like network in the transport of synaptic vesicles towards the presynaptic membrane by a mechanism of chemomechanical transduction is discussed. In the postsynaptic dendrite or dendritic spine, a filamentous network was observed to be attached to the subsynaptic web by means of the E-PTA stain and of the HMM-labeling procedure. The occurrence of an actin-like meshwork in the postsynaptic region is suggested to produce changes in the macromolecular configuration of the postsynaptic membrane by a “ mechanoenzyme” system similar to that described in the mitochondrial membrane.
83 citations
TL;DR: The microtubules, as well as most of the neurofilaments, were disrupted by the glycerination procedure at 4°, and thus no precision about the structural relationship of the actin-like filaments with the latter elements could be added.
Abstract: Nervous tissue pieces from the caudate nucleus and the substantia nigra of the rat were incubated in cold glycerol solutions of decreasing concentrations and then transferred into standard phosphate buffer (pH 7.0) or into tris-K+-Mg++-Ca++ buffer (pH 7.9) containing HMM, prepared from rabbit skeletal muscle by tryptic digestion. As controls, pieces were immersed for an identical period in the same buffers (1) without HMM or (2) with HMM to which had been added 2.5 mM Na+ pyrophosphate or 5 mM ATP. In control neurons smooth-surfaced microfilaments, about 50 A in diameter, were observed. After reaction with HMM, the microfilaments were increased in number and density and in width to 180-200 A. A meshwork was formed. Arrowheads pointing in the same direction were spaced at regular intervals (300-350 A) among short segments of the surfaces of the microfilaments, depending upon the plane of section. More often, however, typical arrowheads were not observed, and the surfaces of the microfilaments were seen coated with polarized side-arms cross-bridging the spaces between adjacent elements at more or less regular intervals. When cross-sectioned, the microfilaments appeared as dense dots from which a material of lesser electron density radiated. Following incubation in HMM solutions containing Na+ pyrophosphate or ATP, no arrowhead structures were seen. Of particular interest was the structural relation of the actin-like filaments with occasional, tapered myosin-like filaments, and with the plasma membrane, which served as anchor points. Mitochondria and smooth ER membranes were observed to be attached to the actin-like filaments or enmeshed in the network. The microtubules, as well as most of the neurofilaments, were disrupted by the glycerination procedure at 4 degrees, and thus no precision about the structural relationship of the actin-like filaments with the latter elements could be added. The role of the actin-like filaments in the transport of material, by a mechanism of chemomechanical transduction, throughout the neuron from sites of synthesis to functional locations, and between several functional locations, is discussed.
82 citations
TL;DR: In this article, the effects of various hormonal nutritional and hematological conditions on alpha fetoproteins (AFP) metabolism in newborn and adult rats and mice were investigated, and it was shown that adrenal and thyroid hormones play an important role in the physiological regulation of AFP metabolism by influencing liver growth and maturation and the proliferation and differentiation of the intermediate pre-hepatocyte cell.
Abstract: An investigation of the effects of various hormonal nutritional and hematological conditions on alpha fetoproteins (AFP) metabolism in newborn and adult rats and mice indicated that adrenal and thyroid hormones play an important role in the physiological regulation of AFP metabolism by influencing liver growth and maturation and the proliferation and differentiation of the intermediate pre-hepatocyte cell. Thus conditions (e.g. neonatal iron deficiency) affecting or interfering with general physiological growth processes also affect AFP metabolism. Albumin and AFP are two proteins with similar physicochemical properties (molecular weight isoelectric point and electrophoretic mobility) dye-binding properties and hormone carrier functions. AFP could thus assume the role of fetal emergency albumin.
80 citations
TL;DR: In this paper, the decomposition of polystyrene samples with molecular weights ranging from 900 to 1.8 × 10 6 have been carried out making use of the differential thermogravimetric and differential scanning calorimetric techniques.
66 citations
TL;DR: In this paper, the C-terminal ethylamide modification into (D-Ala 6) and (D -Trp 6) peptides showed great promise as structures on which to base the development of LH-RH antagonists.
63 citations
TL;DR: The results establish that, in the hypothalamus, somatostatin is mainly concentrated in the median eminence and suggest that periventricular organs can play a role in the regulation of growth hormone secretion.
Abstract: Utilizing the unlabeled antibody peroxidase-antiperoxidase method, we have studied the distribution of somatostatin (growth hormone release-inhibiting hormone) in the guinea pig brain. An immunohistochemical reaction was found in both internal and external zone of the caudal and median portions of the median eminence. Reaction products were also present in the arcuate nucleus in proximity of the third ventricule. The immunostained elements resembled nerve processes. No cell bodies were stained. A positive reaction was also present in the whole organum vasculosum of the lamina terminalis. In the subfornical and subcommissural organs, somatostatin was observed in the ependymal and subependymal layers and the perivascular areas. In the pineal gland, a positive reaction was also found mainly in the perivascular areas. All the other brain areas were completely negative. These results establish that, in the hypothalamus, somatostatin is mainly concentrated in the median eminence and suggest that periventricular organs can play a role in the regulation of growth hormone secretion.
60 citations
TL;DR: In this paper, both physical and numerical arguments are presented which support a Batchelor-type solution for the flow between infinite disks, in which part of the fluid rotates as a solid body.
Abstract: The problem of obtaining a numerical solution for the steady flow between two coaxial infinite disks, one fixed and porous, the other rotating, is reduced by von Kaman's hypothesis to solution of a system of nonlinear equations. A Newton-type iteration results in several solutions to these equations, as a number of authors have already indicated. Nevertheless, an interval in which only one solution is found exists for small values of the Reynolds number based on the angular velocity of the rotating disk, the distance between the disks and the kinematic viscosity of the fluid. At large values of this Reynolds number, two solutions appear and have been the subject of intense controversy.In this paper, both physical and numerical arguments are presented which support a Batchelor-type solution for the flow between infinite disks, in which part of the fluid rotates as a solid body. The other solution, following Stewartson, assumes that the velocity of the fluid outside the boundary layers is entirely axial. This only seems to be verified experimentally when the distance between the disks is large compared with the (finite) radius of the disks.
58 citations
TL;DR: Attention is drawn to the occurrence of colonic tumors at the site of ureterosigmoidostomy.
TL;DR: A specific concentration of radioactivity was found in the striatum and reticular nucleus of the thalamus, which could be correlated with the previously reported effects of MSH on the brain of animals and man.
Abstract: 125 I-α-melanocyte-stimulating hormone (MSH) was injected into the carotid artery of the rat and the radioactivity localized by radioautography. Radioactivity in the areas surrounding the ventricles and blood vessels after administration of 125 I-α-MSH but not 125 I-luteinizing hormone indicated passage of labeled material through the blood brain barrier. A specific concentration of radioactivity was found in the striatum and reticular nucleus of the thalamus. This localization, particularly in the thalamus, could be correlated with the previously reported effects of MSH on the brain of animals and man.
TL;DR: The distribution of radioactivity after intrajugular injection of 125I-labelled alpha-melanocyte-stimulating hormone (alpha-MSH) was studied by whole-body autoradiography of the mouse and by direct measurement ofRadioactivity in individual organs of the rat.
Abstract: The distribution of radioactivity after intrajugular injection of 125I-labelled alpha-melanocyte-stimulating hormone (alpha-MSH) was studied by whole-body autoradiography of the mouse and by direct measurement of radioactivity in individual organs of the rat. Very high uptake of radioactivity in the pineal gland was measured 5 min after the injection of (125I)alpha-MSH. Lower levels of accumulation of radioactivity were found in the kidney and in the posterior (including intermediate) lobe of the pituitary. High uptake was also found in the thyroid, stomach, and oesophagus. The specificity of uptake of (125I)alpha-MSH into the pineal and pituitary is suggested by the very low uptake of Na125I into those tissues.
TL;DR: The telecenphalon of Rana pipiens appears more profusely innervated by axons of the 5-HT-type than by those of the CA-type, which has been related to the fact that in the frog brain stem the CA neuronal somata are scarce in comparison to the highly developed5-HT neuronal systems.
TL;DR: The recent development of matrix methods, based on phase-space dynamics, allows the ready calculation of ion trajectory stability and ion displacements in quadrupole fields as mentioned in this paper, and detailed studies have been made of the efficiency of ion trapping in the three-dimensional quadrupoles field for various conditions of mass analysis.
TL;DR: In this paper, two approximate solutions are developed that permit removing one of the dimensions from the integrations, i.e., the rate of rotational dissociation at a given vibrational energy, averaged over an appropriate non-equilibrium vibrational distribution function.
TL;DR: This observation supports the suggestion that l -asparaginase inhibits lymphocyte blastogenesis by its action on the membrane rather than by depletion of exogenous asparagine, and suggests a possible role for tryptophan and isoleucine in the regulation of the lymphocyte cell cycle.
TL;DR: The amount of corticosterone bound to proteins in the adenohypophysis and dorsal hippocampus was studied concurrently with the plasma ACTH concentration in 4-week adrenalectomized male rats under steady-state conditions and a suggestive relationship was observed between ACTH inhibition by cortic testosterone and saturation of the pituitary binding sites.
Abstract: The amount of corticosterone bound to proteins in the adenohypophysis and dorsal hippocampus was studied concurrently with the plasma ACTH concentration in 4-week adrenalectomizedmale rats under steady-state conditions achieved by infusing the steroid at a constant rate for 45 min. Corticosterone binding was measured by gel chromatography on Sephadex LH-20, using a TE buffer containing 0.4M NaCl. No saturation was observed in whole homogenates and supernatants with increasing plasma corticosterone concentrations. However, corticosterone binding by the pituitary and by one of two types of hippocampal receptors evidenced saturation within our range of corticosterone infusion rates. Indeed, Scatchard plots allowed us to distinguish two types of binding sites in the hippocampus. The first, saturated at a low corticosterone concentration, has an association constant of 3.0 × 108 M−1 with a number of binding sites estimated at 150 × 10−15 mol/mg protein, whereas the second is associated with non-specific bindin...
TL;DR: Removal of the contralateral motor cortex in cats with a unilateral lesion of the entopeduncular nucleus abolishes spontaneous and drug-induced circus movements.
TL;DR: The striopallidal (extrapyramidal) system, which includes the rubro-olivo-cerebella-rubral loop and certain brain stem relay nuclei, and Vestibulospinal nervous pathways is studied.
TL;DR: Results clearly indicate that some material from the third ventricle can rapidly diffuse between cells and axons of the median eminence to reach the fenestrated capillaries of the pituitary portal plexus and the posterior pituitaries without involving an active transport by tanycytes.
Abstract: An active role of the ependymal cells (tanycytes) of the median eminence in the transport of hypothalamic hormones has been recently suggested. In order to investigate the fate of material present in the cerebrospinal fluid, a protein tracer, horse-radish peroxidase (HRP) was injected into the left lateral ventricle of rats. Two minutes after the injection, HRP had largely diffused between tanycytes and hypendymal cells. As soon as 5 min after the injection, HRP had completely penetrated all the layers of the median eminence. A few labelled vesicles and lysosomes were occasionally seen in ependymal and glial cells. At longer time intervals (20 min, 1 and 4 hrs), a reaction was observed in the lumen of fenestrated capillaries of the pituitary portal plexus. In many nerve endings of the external zone, vesicles and lysosomes were seen to contain HRP. An interesting observation was the localization of HRP between nerve endings and cells in both the pars nervosa and the pars intermedia of the pituitary gland. No reaction was recorded in the anterior pituitary and the kidney. Seventeen hours after the injection, the extracellular space was free of reaction but a few positive intracellular structure were still found. These results clearly indicate that some material from the third ventricle can rapidly diffuse between cells and axons of the median eminence to reach the fenestrated capillaries of the pituitary portal plexus and the posterior pituitary without involving an active transport by tanycytes.
TL;DR: A high incidence of mortality of the endoparasitoid Aphidius nigripes was observed when its host, Macrosiphum euphorbiae, was treated with juvenile hormone analogs.
Abstract: A high incidence of mortality of the endoparasitoid Aphidius nigripes was observed when its host Macrosiphum euphorbiae, was treated with juvenile hormone analogs Larval and pupal stages of the parasitoid were susceptible Off-target effects on natural enemies may seriously limit the use of juvenile hormone analogs, especially in integrated control programs
TL;DR: In this article, the Raman spectra of hydrogen and deuterium peroxides have been studied by the matrix-isolation technique in solid argon at 10 K. The first three symmetric fundamentals were observed for peroxide monomers only.
TL;DR: Except for the lateral cell group which could be peculiar to the cat, the topographical distribution of MA nerve cell bodies and axon terminals in the hypothalamus of the cat appears similar to the morphological organization of the MA neuronal elements in the amygdala of the rat.
Abstract: Three distinct groups of monoamine (MA)-containing nerve cell bodies have been visualized in the hypothalamus and preoptic area of the cat by means of the Falck-Hillarp fluorescence histochemical technique. First, numerous small-sized catecholamine (CA) type neurons were disclosed within the ventral half of the periventricular area in the supraoptic and middle hypothalamic regions. The round to oval neurons of this medio-ventral group were more especially abundant around the base of the third ventricle, within the arcuate and supraopticus diffusus nuclei. Numerous medium-sized CA perikarya identified as the dorsal group, were also mapped out in the dorsal and posterior hypothalamic areas. Finally, a small population of both CA and serotonin (5-hydroxytryptamine, 5-HT)-containing neurons was disclosed within the lateral area of the middle and mammillary hypothalamic regions. These multipolar or elongated neurons which compose the lateral group were lying either along the ventrolateral surface of the hypothalamus or around the ventrolateral aspect of the fornix. In addition to these three MA cell groups, a few cells displaying a fluorescence of the CA type were also visualized in the so-called "dorsal chiasmatic nucleus" after alpha-methyl-dopa treatment. High density of CA axon terminals were found, on the other hand, in the extrenal layer of the median eminence, in the dorsomedial, paraventricular supraoptic and suprachiasmatic nuclei, and also within nucleus interstitialis of stria terminalis. In the present study, however, it was possible to identify with certainty any concentration of 5-HT axon terminals in the cat hypothalamus. Therefore, except for the lateral cell group which could be peculiar to the cat, the topographical distribution of MA nerve cell bodies and axon terminals in the hypothalamus of the cat appears similar to the morphological organization of the MA neuronal elements in the hypothalamus of the rat.
01 Sep 1975-Journal of Comparative Physiology A-neuroethology Sensory Neural and Behavioral Physiology
TL;DR: Beavers studied under natural conditions near Québec City, Canada, displayed a yearly cycle of patterns of activity rhythms, suggesting that annual variations in the beaver's physiological state affect their reaction towards the presence or absence of a Zeitgeber.
Abstract: Beavers studied under natural conditions near Quebec City, Canada, displayed a yearly cycle of patterns of activity rhythms. In winter, the beaver colonies had a free-running circadian rhythm of period length 26.25 to 28.0 h, with or without relative coordination, depending on available light intensity, which in turn depends on ice and snow cover conditions; in summer, their activity rhythm followed a “normal” 24 h period. Transitions between these two patterns suggest that annual variations in the beaver's physiological state affect their reaction towards the presence or absence of a Zeitgeber.
TL;DR: The use of Lyapunov functions in the design of a fixed controller for model reference systems results in a bang-bang control as discussed by the authors, where the motion in the neighborhood of the switching surface is analyzed and conditions are found that ensure stable trajectories.
Abstract: The use of Lyapunov functions in the design of a fixed controller for model reference systems results in a bang-bang control. The motion in the neighborhood of the switching surface is analyzed and conditions are found that ensure stable trajectories. It is shown that the Lyapunov design verifies these conditions. The last part of the trajectories appears to be a sliding motion, forcing the plant to track the model. The results are illustrated by a simulation example.
TL;DR: Not only the amplitude but also the speed of LH response are maximal during the afternoon of proestrus and minimal on diestrus I, while the finding of similar changes of pituitary sensitivity to LH-RH under in vitro conditions using pituitaries collected at the same stag-s of the estrous cycle is ascertanied.
TL;DR: Although silicone fibers are among the most compatible with tissue and blood, numerous deposits are observed after their prolonged usage in a capillary membrane oxygenator, even when the blood has been properly heparinized, a scanning electron microscope study shows.
TL;DR: The results after intracarotid injection suggest that L-prolyl-L-leucyl-glycinamide may cross the blood brain barrier and the results after intraventricular injection suggest sites of localization which might be correlated with the previously reported effects of the tripeptide on the brain.
Abstract: Tritiated L-prolyl-L-leucyl-glycinamide was injected into the carotid artery or lateral ventricle of rats and the radioactivity localized by radioautography. After intracarotid administration, the radioactivity labeled the meninges, ependymal cells bordering the ventricles, and cells of the choroid plexus, as well as the median eminence and subfornical organ and thus may have reached the cerebrospinal fluid. After intraventricular injection, specific localization of radioactivity was found in cells of the nucleus lateralis septi, nucleus medialis septi, putamen, globus pallidus, indusium griseum, hippocampus, corpus callosum, and meninges. The results after intracarotid injection suggest that L-prolyl-L-leucyl-glycinamide may cross the blood brain barrier and the results after intraventricular injection suggest sites of localization which might be correlated with the previously reported effects of the tripeptide on the brain.
TL;DR: In this paper, two triangular mixed finite elements are developed for the linear and non-linear analysis of thin shallow shells, where the unknown variables at the finite element nodes include not only the three displacements and bending stress resultants, but also the membrane stress endants.