Showing papers by "University of Ottawa published in 1968"
TL;DR: In vitro ouabain, at relatively low concentrations, inhibits the blastogenic action of PHA as well as the incorporation of tritiated nucleosides into nucleic acid; excess potassium in the culture medium diminishes or prevents this effect of ouABain.
Abstract: DURING a study of the blastogenic action of phyto-haemagglutinin (PHA) on small lymphocytes in vitro1, we found cause to speculate that interference with membrane ion transport might selectively inhibit part of the sequence of events2–7 required for cell transformation. We therefore investigated8 the effect of the cardiac glycoside, ouabain (‘G-Strophanthin’), which is known selectively to inhibit coupled sodium and potassium transport9–11. We now report that in vitro ouabain, at relatively low concentrations, inhibits the blastogenic action of PHA as well as the incorporation of tritiated nucleosides into nucleic acid; excess potassium in the culture medium diminishes or prevents this effect of ouabain.
140 citations
TL;DR: The results indicate a high specificity of the enzyme for the 17α-hydroxyl group on phenolic steroids which are already attached through position 3 to glucosiduronic acid.
36 citations
TL;DR: The evidence indicates that the increased hexokinase activity induced by 17β-estradiol may entail an acceleration of the synthesis of certain RNA species.
Abstract: Administration of estradiol to ovariectomized rats induced new synthesis of uterine hexokinase which was prevented by actinomycin D, 5-fluorouracil, cycloheximide, or ethionine. The estradiol-induced increase in uterine hexokinase activity was detectable as early as 4 hours. The increase in enzyme activity was dependent upon the dose of the hormone. The evidence indicates that the increased hexokinase activity induced by 17β-estradiol may entail an acceleration of the synthesis of certain RNA species.
36 citations
TL;DR: It is shown that all catechols are substrates of the enzyme, but that 4-nitrocatechol can act as a non-competitive inhibitor of the O -methylation of another catechol.
35 citations
TL;DR: In this paper, anodically-formed, thin film oxide layers at nickel in alkaline solutions have been studied in relation to the behaviour of bulk nickel oxide examined in previous work.
31 citations
TL;DR: 3H-thymidine-labeled rats have shown cells with radioactive nuclei at the cementodentinal junction 3 days later and none thereafter, pointing to a turnover of young cementum comparable to that of trabecular bone.
Abstract: Cementum resorption (“cementolysis”) comparable to osteocytic osteolysis and concomitant with cementocyte maturation has been observed in alpharadiographs of rat molars. This phenomenon was enhanced by administration of parathyroid extract (Para-Thormone, Lilly) and retarded by feeding a diet containing 1% MgO for 48 days.
30 citations
TL;DR: The results presented suggest that new RNA and protein synthesis may be involved in the observed androgen-induced increases in phosphofructokinase activity in the prostate and seminal vesicles of the orchidectomized rat.
Abstract: 1. The hormonal regulation of phosphofructokinase was investigated in the accessory reproductive organs of the orchidectomized rat. 2. Phosphofructokinase activities declined to 51% and 47% in the prostate and 9% and 6% of the normal values in seminal vesicles 4 and 8 weeks after castration respectively. Administration of testosterone (100μg./100g. body wt.) for 3 days reversed substantially the effects of orchidectomy, and phosphofructokinase activity increased to 173% in the prostate and 536% in seminal vesicles as compared with the values of castrated controls. 3. Time-course studies demonstrated that after a single injection of testosterone (5mg./100g. body wt.) phosphofructokinase activity was maximally elevated to 236% in the prostate and 342% in seminal vesicles at 24hr. 4. Dose–response studies revealed that 2·5mg. of testosterone propionate/100g. body wt. was the minimal amount necessary to induce significant increases in enzyme activity in both accessory sex organs; maximal increases were obtained with a dose of 5mg./100g. body wt. 5. The observed enzyme increases induced by testosterone were inhibited by the simultaneous administration of oestradiol-17β, and phosphofructokinase activity in this group of rats remained at 97% in the prostate and 137% of the control values in seminal vesicles. Oestradiol-17β by itself failed to produce any significant effect on enzyme activity in either of these secondary sexual tissues. 6. The nature of the testosterone-induced increases in phosphofructokinase activity was studied by using a variety of inhibitors of RNA and protein synthesis. Cycloheximide, 5-fluorouracil and ethionine largely blocked the androgen-stimulated rise in enzyme activity observed 24hr. after steroid injection. The inhibitory effect of ethionine was completely reversed by the simultaneous administration of methionine. 7. Actinomycin, which is known to inhibit the synthesis of messenger RNA as well as the synthesis of other cellular RNA fractions, when given simultaneously with the hormone, also inhibited the testosterone-induced increases in prostatic and seminal-vesicular phosphofructokinase. However, when the antibiotic was given 6 or 12hr. after injection of the steroid, practically no inhibition of phosphofructokinase induction was obtained. This indicates that, once the enzyme-forming machinery is turned on and allowed to operate for a few hours, actinomycin is incapable of reversing the hormone-induced enzyme responses. 8. The results presented suggest that new RNA and protein synthesis may be involved in the observed androgen-induced increases in phosphofructokinase activity in the prostate and seminal vesicles of the orchidectomized rat.
29 citations
TL;DR: Data indicating the effectiveness of audio-analgesia are presented and the need for further studies on this topic is discussed.
Abstract: Data indicating the effectiveness of audio-analgesia are presented.
28 citations
TL;DR: In this paper, the Rice-Ramsperger-Kassel-Marcus formations of unimolecular reaction rates have been applied to the processes C2H6→ 2CH3, C2OCH3→ CH2O + CH3, and CH2H5→ CH4+H.
Abstract: The Rice-Ramsperger-Kassel-Marcus formations of unimolecular reaction rates have been applied to the processes C2H6→ 2CH3, C2H5→ C2H4+ H and CH2OCH3→CH2O + CH3, various models being considered. For the C2H6 dissociation satisfactory agreement is obtained on the basis of two models; one involving softened vibrations, and one involving two active rotations in the activated complex, in both cases a correction being made for the centrifugal effect. For the C2H5 decomposition a model involving one active rotator in the activated complex and two active rotators in the energized radical leads to excellent agreement. For the CH2OCH3 decomposition good agreement was obtained on the basis of a model consisting of two active rotators in both the activated complex and the energized radical.
23 citations
TL;DR: In this article, the RRKM formulation of unimolecular reaction theory has been extended to take the back reaction into account, and the isomerizations of cis-butene-2, cyclobutene and cyclopropane are derived.
Abstract: Several previous calculations relating to rates of unimolecular isomerizations have led to satisfactory agreement with experiment only if it is assumed that there is a low efficiency of energy transfer on collision. Other evidence, however, indicates that collisions in unimolecular processes are “strong”, having a high probability of transferring vibrational energy. This discrepancy is traced to the fact that previous treatments have neglected the back reaction, in which the highly energized isomer molecule is reconverted into a reactant molecule. In the present work the RRKM formulation of unimolecular reaction theory has been extended to take this back reaction into account. Calculations are made for the isomerizations of cis-butene-2, cyclobutene and cyclopropane. Agreement is good for the first two systems. For cyclopropane, calculations based on the assumption that a C—H stretch is the reaction co-ordinate still require a collision efficiency of 0.25 for agreement with experiment.
23 citations
01 Jan 1968
TL;DR: The results suggest that sensitive and resistant cells are equally permeable toProflavine but differ in the ease with which metabolites cause them to release bound proflavine, and that these differences do not account completely for the ability of resistant cells to grow in high proflavines.
Abstract: Both Escherichia coli B and a proflavine-resistant mutant, E. coli B/Pr, took up the same amounts of proflavine when suspended in buffer containing the dye. In growth media, however, sensitive cells took up more proflavine than did resistant cells. Adding growth media or any one of several constituents of these media, including amino acids, glycerol, pyruvic acid, and metabolizable sugars, to resistant cells that had taken up proflavine in buffer caused them to lose the dye, but had less or no effect on sensitive cells. Certian salts caused an equal release of proflavine from resistant and sensitive cells. Proflavine released from resistant cells by glucose was not changed chemically. The effects of temperature and metabolic inhibitors suggest that proflavine uptake is a passive process but that its release may be an active one, dependent on metabolism. Glucose had more effect on the proflavine binding of E. coli B grown in a minimal medium than on that of cells grown in a complex medium. E. coli B was less susceptible to proflavine when growing in a minimal medium. The effects of other synthetic media on proflavine susceptibility of E. coli B were also studied. Deoxyribonucleic acid and envelopes from sensitive and resistant cells bound the same amounts of proflavine, and no difference was seen in the site of dye binding when sensitive and resistant cells that had taken up proflavine in buffer were sonically broken and fractionated. The results suggest that sensitive and resistant cells are equally permeable to proflavine but differ in the ease with which metabolites cause them to release bound proflavine. So far, however, these differences do not account completely for the ability of resistant cells to grow in high proflavine concentrations.
TL;DR: Interaction of steroids with several enzyme proteins exhibits poorly defined difference spectra which are unlike the ones for serum albumins, which are attributed to perturbation of aromatic amino acid bands.
TL;DR: The identity of a ketone (cyperenone) common to Cyperus scarosius, C. articulatus and C. rotundus has been established by PMR and mass spectral study of its 2,4-dinitrophenylhydrazone (DNP) as discussed by the authors.
TL;DR: In this article, a simple method for measuring diffusion coefficients of gases in liquids using capillary cells has been shown to give accurate results for the diffusivities of carbon dioxide in water, methane in carbon tetrachloride, and CO 2 in ethanol when compared with reported values.
Abstract: A simple method for measuring diffusion coefficients of gases in liquids using capillary cells has been shown to give accurate results for the diffusivities of carbon dioxide in water, methane in carbon tetrachloride, and carbon dioxide in ethanol when compared with reported values. Diffusivities were also measured at 30°C. for ethane in n-hexane and ethane in n-heptane, and at 40°C. for ethane in n-heptane. The steady-state capillary cell technique appears to be capable of giving reliable diffusivities for a large number of gas-liquid systems.
On a trouve qu'une methode simple, servant a mesurer les coefficients de diffusion des gaz dans des liquides et utilisant dee cellules capillaires, donnait des resultats preeis lorsqu'il s'agissait dcs diffusivites de l'anhydride carbonique dans l'eau, du methane dans le tdtrachlorure de carbone et de l'anhydride carbonique dans l'alcool ethylique, et qu'on comparait les dits resultats avee des valeurs deja rapportees. On a aussi mesure les diffusivites a 30°C., dans le cas de I'ethane dans I'hexane normal et dans l'hextane normal, et a 40°C. pour 1′ethane dans I'heptane normal. La methode a base de cellules capillairee et a regime permanent semble capable de fournir des valeurs fiables sur la diffusivite dana lc cas d'un grand nombre de systemes gae-liquide.
TL;DR: In this article, the anomalous surface effect is found to exist in the filtration of non-Newtonian fluids and the specific cake resistance in the case of the non-newtonian sludge and the ratio of the effective slip velocity to the pore velocity are found to be functions of both the CMC concentration and the pressure drop across the filter bed.
Abstract: Equations of motion characterizing the flow of incompressible, time-independent non-Newtonian fluids, exhibiting the anomalous surface effect, through compressible porous media are developed. Approximations are made to arrive at workable filtration equations for slurries of non-Newtonian (power-law) fluids. The constant-pressure and constant-rate filtration relationships developed are verified experimentally using slurries of calcium carbonate in water and dilute CMC solutions. The anomalous surface effect is found to exist in the filtration of the non-Newtonian fluids. The specific cake resistance in the case of the non-Newtonian sludge and the ratio of the effective slip velocity to the pore velocity are found to be functions of both the CMC concentration and the pressure drop across the filter bed.
On a mis au point des equations de mouvement caracterisant l'ecoulement des fluides non-newtoniens incompressibles et independents du temps, lesquels font voir l'effet d'une surface anormale dans des milieux poreux et compressibles. On a eu recours a des approximations pour mettre au point des equations assez satisfaisantes pour la filtration de suspensions epaisses de fluides non-newtoniens (loi d'energie). On a evalue experimentalement la correlation entre la filtration a pression constante et celle a vitesse constante, au moyen de coulis de carbonate de calcium dans l'eau et de solutions diluees de carboxymethyl-cellulose. On a trouve que l'effet de surface anormale existait dans la filtration de fluides non-newtoniens. On a aussi constate que la resistance specifique du cake de filtration, dans le cas d'un coulis non-newtonien et le rapport entre la velocite effective de glissement et la velocite des pores etaient fonctions a la fois de la concentration de la carboxymethylcellulose et de la chute de pression dans le lit filtrant.
TL;DR: The present results complement the earlier findings on the hormonal control of uterine phosphofructokinase and lend additional support to the view that stimulation of the synthesis of certain RNA species is one of the primary actions of estrogenic hormones.
TL;DR: Although carcinoma of the colon and rectum is dramatically more common in older persons, its behavior, once it has developed, is similar at all ages and therapy should not be altered simply because the patient is young or old.
Abstract: Although carcinoma of the colon and rectum is dramatically more common in older persons, its behavior, once it has developed, is similar at all ages. Hence, a factor associated with aging affects the development of cancer of the colon and rectum, but not the behavior of the developed tumor. Therefore, therapy should not be altered simply because the patient is young or old.
TL;DR: In this article, the geometrical and structural isomerizations of cyclopropane and the decomposition of cyclobutane are considered from the standpoint of the RRKM theory.
Abstract: The geometrical and structural isomerizations of cyclopropane and the decomposition of cyclobutane are considered from the standpoint of the RRKM theory. The fall-off curves depend critically on the high-pressure Arrhenius parameters; the use of the latest values leads to good agreement with experiment in most cases. Whether or not a biradical mechanism is assumed, there is little effect on the calculated fall-off curves. The treatments are applied to isotope effects as functions of pressure and temperature. The activation energy difference ED–EH varies with pressure in a complicated way, a conclusion that throws light on apparent discrepancies between the results of different workers.
TL;DR: 1 Trypsin digestion of Micrococcus lysodeikticus polynucleotide phosphorylase causes a progressive increase in electrophoretic mobility in polyacrylamide gels of the single active degradation product, and a marked increase in primer requirement for CDP polymerization occurs before a more mobile product is formed.
Abstract: 1. Trypsin digestion of Micrococcus lysodeikticus polynucleotide phosphorylase (nucleoside diphosphate–polynucleotide nucleotidyltransferase) causes a progressive increase in electrophoretic mobility in polyacrylamide gels of the single active degradation product. 2. A marked increase in primer requirement for CDP polymerization occurs before a more mobile product is formed. 3. α-Chymotrypsin digestion yields a product that separates into several active species on polyacrylamide-gel electrophoretograms. 4. No separation of ADP-and CDP-polymerization activities occurs during electrophoresis after either trypsin or α-chymotrypsin treatment.
TL;DR: It is shown that such a realization exists if and only if the flow table is asynchronous definite, where the asynchronous definite property is a modification of the definite property of synchronous sequential machines.
Abstract: An asynchronous unit delay is an n input n output asynchronous sequential circuit in which the present value of the output n-tuple is equal to the value of the input n-tuple prior to the last input change. This paper considers the problem of determining when a fundamental mode flow table is realizable as a feedback-free connection of asynchronous unit delays. It is shown that such a realization exists if and only if the flow table is asynchronous definite, where the asynchronous definite property is a modification of the definite property of synchronous sequential machines. A straightforward method of realizing asynchronous definite flow tables without critical races by feedback-free circuits of asynchronous unit delays and combinational gates is developed. The use of asynchronous unit delays for definite tables avoids complicated secondary assignment problems, results in circuits with very simple structure, and brings closer the theories of synchronous and asynchronous sequential machines.
TL;DR: Intact yeast (Saccharomyces cerevisiae) protoplasts were prepared by treating cells grown in a glucose medium with snail gut enzyme and cellobiose-grown cells of the same strain of yeast could not be converted into protoplast by the snail enzyme procedure.
Abstract: Intact yeast (Saccharomyces cerevisiae) protoplasts were prepared by treating cells grown in a glucose medium with snail gut enzyme. Preparations fixed in a modified Carnoy's fluid and stained with uranyl acetate were studied in the electron microscope. All traces of cell wall were absent in these preparations. The plasma membrane was found to consist of two electron dense layers separated by a less dense layer, the overall thickness being approximately 80A. Cellobiose-grown cells of the same strain of yeast could not be converted into protoplasts by the snail enzyme procedure.
TL;DR: In this paper, the average velocity or pressure drop in the flow of non-Newtonian fluids in regular polygonal and star-shaped conduits of arbitrary cross section is predicted.
Abstract: A method was proposed earlier(1) for prediction of the average velocity or pressure drop in the flow of non- Newtonian fluids in conduits of arbitrary cross section. The method requires only a knowledge of two geometric parameters which characterize the flow geometry, and the fluid model equation. In this paper, evaluations of geometric parameters are presented for infinite and finite (enclosed)square and triangular arrays of cylinders, and for regular polygonal and star-shaped conduits. With these parameters, predictions of the average velocity or related variables for the Zlow of any arbitrary non-Newtonian fluid can now be made. Comparisons are made with recent analytical solutions and experimental data pertaining to non-Newtonian flow in concentric annuli, and equilateral and right isosceles triangular ducts, which give additional support to the reliability of the proposed method.
Dane un travail prkbdent(l) on a decrit une mbthode pour predire la vilociti moyenne ou l'abaissement de prerrsion dans l'icoulement des flnides non-newtoniens dans des eonduites de coupe arbitraire. La mbthode n'exige qn'une connaissance de deux paramktres giomitriques qui caract& risent la ghmbtrie de I'bcoulement et l'bquation modele fluide. On prbsente, dans le travail actuel, des bvaluations de parametres ghmbtriques dans le cas de rangbes infinies et finies (closes ), carrbes et triangulaires de cylindres, ainsi que pour des conduites en forme de polygones rbguliers et d'btoiles. GrPce i ces paramktres, on peut maintenant prddire la velocite moyenne ou les variables apparentees pour 1′ecoulement de n'importe quel fluide arbitraire et non-newtonien. On fait des comparaisons avec des solutions analytiques rkentes et des rdsultats expbri- mentaux qui ont trait P un bcoulement non-newtonien dans des anneaux coneentriques et des conduites en forme dtriangles bquilatdraux et isockles droits, ce qni appuie davantage la confiance qu'on accorde i la mbthode proposbe.
TL;DR: In this article, the current distribution and potential profile at a thin wire anode of appreciable ohmic resistance under conditions where longitudinal potential drop in the electrolyte solution is minimized.
TL;DR: An electron microscopic study of the lateral and medial nuclei of the amygdala was undertaken as the first step towards establishing a basis for an experimental investigation of the afferent projections to the amygdaloid complex.
Abstract: An electron microscopic study of the lateral and medial nuclei of the amygdala was undertaken as the first step towards establishing a basis for an experimental investigation of the afferent projections to the amygdaloid complex. The ultrastructural features of the two nuclei are, in general, similar. However two differences deserve mention. First, in the medial nucleus it was observed that frequently at least half the soma membrane was in apposition with glial processes. Secondly, dendritic spines were more frequently seen in the lateral nucleus. These differences may be related to the different phylogenetic origin of the two cell groups. Boutons “en passant” are a common feature in both nuclei. Most of the synaptic knobs could be assigned, on the basis of their vesicle content, to one of the following groups: 1. round to oval vesicles, uniform in size; 2. round to oval vesicles, varying in size; 3. predominantly flattened vesicles; and 4. predominantly dark core vesicles. At present there is not sufficient data concerning the afferents of the amygdala to allow any correlation of these four bouton types with the different incoming fibre projections.
TL;DR: In this article, the hydrogenation of ethylacetylene has been studied in a constant-volume static system over a nickel-pumice catalyst between 20 ° and 60 °C.
TL;DR: In this article, the authors reported the discovery of an anomaly in the thermal expansion of gold below 8°K as well as the experimental confirmation of the low temperature lattice Gruneisen gamma of gold predicted by Collins.
01 Jan 1968
TL;DR: The tissue distribution of enzymatic activities in intestinal metaplasia stomachs exhibiting chronic gastritis was compared histochemically with that of the small intestine in man.
Abstract: The tissue distribution of enzymatic activities in intestinal metaplasia stomachs exhibiting chronic gastritis was compared histochemically with that of the small intestine in man.
TL;DR: In this paper, an analysis of the anomalous behaviour and associated drag reduction encountered primarily in the turbulent flow of viscoelastic non-Newtonian fluids was conducted and it was shown that these fluids conform to the same general correlation scheme formulated for the purely viscous fluids when allowance is made for an effective velocity of slip at the wall attributable primarily to an increased laminar sub-layer thickness.