Showing papers by "Université de Sherbrooke published in 1980"
TL;DR: In this paper, the heat capacities per unit volume and densities of aqueous solutions of 2-propanol, neopentanol, tert-amyl alcohol, 2-amino-2-methylpropanols, triethylamine and diethylmethylamines were measured, in many cases as a function of temperature.
Abstract: The heat capacities per unit volume and the densities of aqueous solutions of 2-propanol, neopentanol, tert-amylalcohol, 2-amino-2-methylpropanol, triethylamine and diethylmethylamine were measured, in many cases as a function of temperature, over the whole mole fraction or solubility range. Apparent and partial molal heat capacities, volumes and expansibilities were derived. The concentration dependence of these functions suggest the existence of transitions in some of these systems, in the water-rich region, qualitatively similar to micellization. The large relaxation contribution observed with some of the thermodynamic functions of hydrophobic alcohols and amines suggests a reinforcement of hydrophobic hydration due to strong hydrogen-bonding interactions of the polar groups with water.
133 citations
TL;DR: The data derived from the structure‐activity study suggest that the minimum structure required for the full stimulation of NT receptors in these two preparations is H‐Arg9‐Pro10‐Tyr11‐Ile12‐Leu13‐OH, which appears to contribute mainly to the affinity or binding of NT to its receptor.
Abstract: 1 The stimulatory effects of neurotensin (NT) and several NT fragments were evaluated in two pharmacological preparations: rat stomach strips and isolated spontaneously beating atria of guinea-pigs.
2 In rat stomach strips, NT elicited a dose-dependent contractile effect in concentrations varying between 1.3 × 10-9 and 5.4 × 10-7 M.
3 The contractile effect of NT (1.3 and 5.4 × 10-8 M) in this tissue was not modified by atropine (3.4 × 10-7 M), methysergide (2.0 × 10-6 M), a mixture of cimetidine (8.0 × 10-6 M) and diphenhydramine (7.8 × 10-6 M), indomethacin (1.4 × 10-5 M), 8-Leu-angiotensin II (1.0 × 10-6 M), glucagon (2.0 × 10-6 M) or somatostatin (3.0 × 10-7 M).
4 Rat stomach strips desensitized by bradykinin (6.1 × 10-6 M) or substance P (7.4 × 10-6 M) maintained their sensitivities to NT (1.3 and 5.4 × 10-8 M).
5 In guinea-pig atria, NT produced a dose-dependent positive inotropic action in concentrations varying between 5.4 × 10-10 and 2.7 × 10-7 M.
6 The inotropic effect of NT (2.7 × 10-9 M) was not influenced by methysergide (2.8 × 10-6 M), atropine (3.4 × 10-7 M), practolol (1.5 × 10-5 M), 8-Leu-angiotensin II (1.0 × 10-6 M), or indomethacin (1.4 × 10-5 M), but it was reduced by 37% by cimetidine (4.0 × 10-5 and 2.0 × 10-4 M). A combination of cimetidine (4.0 × 10-5 M) and diphenhydramine (3.9 × 10-6 M) did not produce a greater inhibition of NT than cimetidine alone.
7 Atria desensitized by bradykinin (6.1 × 10-6 M) or glucagon (2.0 × 10-6 M) maintained their sensitivities to NT (2.7 × 10-9 M). Substance P was inactive both as an agonist or antagonist of NT.
8 These results suggest the existence of specific NT receptors in rat stomach strips and guinea-pig atria.
9 The data derived from our structure-activity study suggest that the minimum structure required for the full stimulation of NT receptors in these two preparations is H-Arg9-Pro10-Tyr11-Ile12-Leu13-OH. The sequence PyroGlu1-Leu2-Tyr3-Glu4-Asn5-Lys6-Pro7-Arg8- and the amino acids Ile12 and Leu13 appear to contribute mainly to the affinity or binding of NT to its receptor. The chemical groups responsible for the full activation (intrinsic activity) of NT receptors seem to be located in the sequence -Arg9-Pro10-Tyr11.
100 citations
TL;DR: In this paper, the combined effects of material strain-rate sensitivity and anisotropy on necking or "limit" strain predictions are examined for thin sheets with transversely isotropic properties.
99 citations
TL;DR: In this article, a linear relationship between the variables log A and E was established, which is known as a compensation effect, expressed by the following equation, where w is the weight or mass of pyrolyzing sample at any time t; A is the frequency factor; E is the activation energy; Q is the reaction order, and k is the rate constant.
82 citations
TL;DR: The minimum structure required for the full expression of the myotropic activity of NT in the rat portal vein is -Arg9-Pro10-Tyr11-Ile12-Leu13-OH; Tyr11 appears to be closely involved in the process of NT receptor activation since its replacement with D-Trp or Tyr(Me) produced specific and competitive antagonist of NT.
60 citations
59 citations
TL;DR: The results suggest the participation of histamine, serotonin and possibly other endogenous vasoactive substances, to the hypotensive action of NT in rats and the possible origin of these mediators is discussed.
56 citations
TL;DR: Electron microscopy of thin sections of HEp-2 cells at 1 h after infection with adenovirus type 5 showed that 31% of the virus particles observed were associated with cytoplasmic microtubules.
55 citations
TL;DR: The structure-activity studies performed using several NT fragments and analogues in the isolated perfused rat heart led to the following conclusions: (1) the minimum structure required for the full expression of the biological activity of NT is H-Arg9-Pro10-Tyr11-Ile12-Leu13-OH; (2) the amino acid Tyr in position 11 appears to play a key role in the process of NT receptor activation.
53 citations
TL;DR: The results suggest that the receptors mediating the constrictor action of NT in the coronary vessels of rat hearts are pharmacologically distinct from those subserving the stimulant effects ofNT in rat stomach strips and guinea pig atria.
53 citations
TL;DR: In this article, the authors used the technique of chemical vapour transport to prepare needle shaped single crystal of ZrS3 and reported the Hall coefficient and thermoelectric power of the temperature range 100-500 K.
TL;DR: Most pressure values, except U1 and areas under the curve, were significantly lower in the 456 curves obtained in 38 incontinent women than in normal subjects.
TL;DR: The lack of increment of plasma aldosterone to vasopressin in hypophysectomized animals indicates that the observed in vivo steroidogenic effect in intact animals is probably mediated through other factors.
TL;DR: Hamster adrenals seem to be largely capable of synthesizing cholesterol from small molecules of substrate and endogenous adrenal free cholesterol content may well be involved in regulating its own synthesis.
TL;DR: The data derived from the structure‐activity study suggest that Arg9 and Pro10 mainly contribute to the affinity of neurotensin for its cardiac and smooth muscle receptors, and Tyr11 seems to be more closely involved in the process of receptor activation by NT.
Abstract: 1 The stimulant effects of neurotensin (NT) and NT analogues modified in positions 9, 10 or 11 were evaluated and compared in two pharmacological preparations: the rat stomach strip and the isolated spontaneously beating atria of guinea-pig. 2 The data derived from our structure-activity study suggest that Arg9 and Pro10 mainly contribute to the affinity of neurotensin for its cardiac and smooth muscle receptors. Tyr11 seems to be more closely involved in the process of receptor activation by NT. 3 The order of potency of some NT analogues modified in position 11 (e.g. [D-Phe11]-NT, [D-Tyr11]-NT) was strikingly different from that described in other systems (e.g. hypothermia test and specific mast cell binding). The importance of this observation is discussed.
TL;DR: The urethral pressure profile is influenced by the degree of patient relaxation, which explains marked variations in measured pressure values among normal subjects, as well as the frequent lack of reproducibility in a given subject.
TL;DR: The results suggest the existence of specific receptors for NT in the isolated rat portal vein, and the response of this tissue to NT, and possibly to other peptides, appears to be dependent upon the presence of a functional PG biosynthetic pathway.
TL;DR: In this paper, a mathematical model was used for the calculation of the flow and temperature fields in the fire-ball of an inductively coupled plasma (ICP) under confined and free discharge conditions taking into account gravity and swirl in the sheath gas.
Abstract: A mathematical model was used for the calculation of the flow and temperature fields in the fire-ball of an inductively coupled plasma (ICP) under confined and free discharge conditions taking into account gravity and swirl in the sheath gas. Computations were made for an argon plasma at atmospheric pressure operating at a power level of 3kW and a frequnecy of 3 MHz. Natural convection has a negligible effect on the flow and temperature fields under confined discharge conditions, but a significant effect, for the free plasma discharge. The back flow in the discharge was substantially reduced in the presence of swirl for swirl velocities over the range 0-70 m/s. With a moderate increase in swirl, the conduction heat flux to the wall decreased but increased with the further increase in swirl.
On a employe un modele mathematique pour calculer les profits de vitesse et de temperature, dans la zone incandescente d'un plasma a couplage inductif, et ce, dans les conditions de decharge a l'air libre ou a l'etat confine, en tenant compte de la gravite et du mouvement tourbillonnaire dans l'enveloppe gazeusc. Ces calculs ont ete faits dans le cas d'un plasma d'argon sous pression atmospherique, a une puissance de 3kW et une frequence de 3MHz. La convection naturelle exerce une influence negligeable sur les profils de vitesse et de temperature dans des conditions de decharge confinee, mais elle a un effet important lorsqil agit d'une decharge a l'air libre. En presence de tourbillons,1a vitesse de recirculation dans la decharge a ete bien moindre pour des vitesses tangentielle, vθ, entre 0 et 70 m/s. Aux faibles vitesses tangentielles le flux de chaleur par conduction a la paroi diminuait avec, vθ, et au contraire aux plus fortes, niveau de vθ.
TL;DR: The vascular relaxant effects of histamine, adenosine, isoprenaline, nitroglycerine, papaverine and 3‐isobutyl‐1‐methylxanthine were assessed individually, in strips of rabbit renal artery moderately contracted with noradrenaline in the absence or presence of phosphodiesterase inhibitors (papaversine and IBMX) or verapamil, a Ca2+ antagonist.
Abstract: 1 The vascular relaxant effects of histamine, adenosine, isoprenaline nitroglycerine, papaverine and 3-isobutyl-l-methylxanthine (IBMX) were assessed individually, in strips of rabbit renal artery moderately contracted with noradrenaline (NA) in the absence or presence of phosphodiesterase inhibitors (papaverine and IBMX) or verapamil, a Ca(2+) antagonist.2 The vasodilator effect of histamine was potentiated by papaverine (6.1 x 10(-7) M) and IBMX (4.4 x 10(-5) M) but inhibited dose-dependently by verapamil (5.1 and 51.0 x 10(-7) M).3 Adenosine-induced vascular relaxations were greatly increased in the presence of papaverine (6.1 x 10(-7) M) but significantly reduced in the presence of IBMX (4.4 x 10(-5) M) or verapamil (5.1 and 51.0 x 10(-7) M).4 The vasodilatation produced by isoprenaline was increased in the presence of IBMX (4.4 x 10(-5) M) or papaverine (6.1 x 10(-7) M), but inhibited by verapamil (5.1 and 51.0 x 10(-7) M).5 The vascular relaxant effects of nitroglycerine and papaverine were inhibited in the presence of IBMX (4.4 x 10(-5) M) or verapamil (5.1 and 51.0 x 10(-7) M). Papaverine (6.1 x 10(-7) M) also antagonized nitroglycerine-induced vascular relaxation.6 The vasodilator effect of IBMX was greatly reduced in the presence of papaverine (6.1 x 10(-7) M) or verapamil (5.1 and 51.0 x 10(-7) M).7 The vascular relaxant effect of verapamil was reduced proportionally by raising the extracellular Ca(2+) concentration from 1.25 to 5.0 mM while those elicited by histamine, adenosine, isoprenaline, nitroglycerine, papaverine and IBMX were not modified by this procedure.8 These results were taken as an indication that several vasodilators (e.g. histamine, adenosine, isoprenaline, nitroglycerine, papaverine and IBMX), but not a Ca(2+) antagonist such as verapamil, produce a fraction of their vasodilator effects by promoting Ca(2+) extrusion from and/or Ca(2+) sequestration into the vascular smooth muscle cells, via a cyclic adenosine 3',5'-monophosphate-dependent mechanism.
TL;DR: It is concluded that Mn 2+ and the organic blockers have different mechanisms of action, that varapamil and D-600 have to pass through or enter into the membrane, and that the molecules of D- 600 and verapamIL possess one and two active groups respectively.
TL;DR: In this paper, the dispersion relations for guided magnetic polaritons in an ordered ferromagnetic slab are obtained in an anisotropic system and the phase angles are given for typical values of the parameters.
TL;DR: The complexity of the factional asymmetries of the lower extremities requires new methods in both research and clinical testing, with electrophysiological procedures as a promising aproach as mentioned in this paper.
TL;DR: This article showed that Griliches test is not completely adequate for discriminating among several popular models of advertising effectiveness and, as a result, its use by several researchers in that area has produced in...
Abstract: Griliches’ test is not completely adequate for discriminating among several popular models of advertising effectiveness and, as a result, its use by several researchers in that area has produced in...
01 Jan 1980
TL;DR: In this paper, the effect of intensity and large scale turbulence on the drag coefficient of two-dimensional rectangular cylinders was investigated, and the results showed that the impact of the scale of turbulence is not significant.
Abstract: SUMMARY Tests were performed to investigate the effect of intensity and large scale turbulence on the drag coefficient of two-dimensional rectangular cylinders. The results show that the effect of the scale of turbulence is not significant while the effect of turbulence intensity is important.
TL;DR: Reduction of sodium in the diet was accompanied by no changes or a decrease of the responses of isolated vascular beds and tissues to ATII and NA; the pressor effect of ATII was also reduced, while that of NA was definitely increased.
Abstract: The pressor response to angiotensin II (ATII) and to noradrenaline (NA), as well as the response of vascular beds (hindquarter and kidney) isolated and perfused with Krebs' solution, and the contractions of strips of thoracic aortae, portal veins to the same agents were measured in animals and organs taken from rats maintained on a sodium free diet or made hypertensive with DOCA/salt and in several groups of controls. The myotropic effects of ATII and of 5HT were compared in stomach fundi. The main purpose of the study was to find out how a reduction or an increase of total body sodium and the associated changes of renin production can influence the vascular response to angiotensin and to catecholamines. Reduction of sodium in the diet was accompanied by no changes or a decrease of the responses of isolated vascular beds and tissues to ATII and NA; the pressor effect of ATII was also reduced, while that of NA was definitely increased. Treatment with DOCA/salt and the resulting hypertension were accompanie...
TL;DR: It was found that the pressor response to ATII is increased in S.H.R. while that of NA remains unchanged, and the myotropic effects of ATII and NA are definitely increased in hindquarters, kidneys and strips of veins of S.R., while the responses of thoracic aortae and of stomach fundi are depressed.
Abstract: Vascular reactivity to angiotensin II (ATII) and noradrenaline (NA) have been studied in vivo and in femoral and renal vascular beds taken from spontaneously hypertensive rats (S.H.R.) of 3 and 5 months of age. Moreover, the stimulating effects of the same agents have been measured in strips of thoracic aortae, portal veins and stomach fundi taken from S.H.R. and from renal hypertensive rats (R.H.R.) three weeks after clamping one renal artery (two kidneys hypertention). Results obtained in animals or in organs derived from the two groups of hypertensive rats were compared with controls of the same age or of the same weight. It was found that the pressor response to ATII is increased in S.H.R. while that of NA remains unchanged. The myotropic effects of ATII and NA are definitely increased in hindquarters, kidneys and strips of veins of S.H.R., while the responses of thoracic aortae and of stomach fundi are depressed. No changes are observed in the responses of aortae, veins or stomachs of R.H.R. compared...
TL;DR: The pharmacological properties of two angiotensin II analogues containing carboranylalanine (Car) are reported and Sar-Arg- Val-Tyr-Val-His-Pro-Car is a weak partial agonist showing 15% intrinsic activity and a very long lasting action, specific for the angiotENSin II receptor of the rabbit aorta.
TL;DR: This model provides for androgen receptor binding of progesterone and its analogues through the π-orbital of the pregnane side-chain and the possible role of D-ring binding in assigning androgenic agonist or antagonist activity is discussed.
TL;DR: In this paper, the authors examined electrical arcing under fire conditions and explained why arcs are started in fire conditions, while they are difficult to start under normal conditions, and showed that arcs are more likely to be started under fire than in normal conditions.
Abstract: Electrical arcing under fire conditions is examined in this paper. It explains why arcs are started under fire conditions, while they are difficult to start under normal conditions.