bluuebunny/crossref_metadata_2025_split huggingface dataset:
Inhibition of glutamate decarboxylase by salicylate in vitro
Authors: McArthur N , Smith M J H 
Published: April 2011

Abstract
Salicylate inhibits the activity of glutamate decarboxylase from Escherichia coli by a reversible mechanism, but high concentrations of the drug denature the enzyme protein
Salicylate inhibits the activity of glutamate decarboxylase prepared from Escherichia coli and rat brain (Gould, Huggins & Smith, 1963; Gould & Smith, 1965). It was suggested that the mechanism of inhibition involved an irreversible combination of the drug with the enzyme protein. This mechanism has not been confirmed in the present work. High concentrations of salicylate denature, and lower concentrations cause a reversible inhibition of the bacterial enzyme.
The dissolution of commercial aspirin
Authors: Mitchell A G , Saville Dorothy J 
Published: April 2011

Abstract
Two samples of commercial aspirin showing a difference in intrinsic dissolution rate have been studied. Crystallographic examination and solubility determinations failed to reveal any difference between them. The effects of agitation and temperature on intrinsic dissolution rates showed that the samples had different thermodynamic activities and, depending on the conditions, the metastable form was capable of rapid reversion to a more stable form.
A comparison of the effects of (±)-propranolol and (+)-propranolol in anaesthetized dogs; β-receptor blocking and haemodynamic action
Authors: Barrett A M 
Published: April 2011

Abstract
The adrenergic β-receptor blocking activities of (±)-propranolol and (+)-propranolol have been compared in anaesthetized dogs, using isoprenaline as the agonist. (+)-Propranolol possessed less than one fiftieth the potency of (±)-propranolol. Intravenous (±)-propranolol (0·25 mg/kg) produced a six-fold increase in the isoprenaline dose ratio and significantly lowered heart rate, cardiac contractile force, ejection rate and tension time index. The same dose of (+)-propranolol had no effect on the isoprenaline dose ratio nor did it significantly alter these haemodynamic variables. Since both isomers of propranolol have equivalent membrane stabilizing properties it was concluded that the haemodynamic effects of (±)-propranolol at this dose level were due to specific β-blockade and not to any “quinidine-like” properties. Higher doses of (+)-propranolol (1·25 mg/kg) significantly reduced heart rate and cardiac contractile force whilst increasing atrio-ventricular conduction time without raising the threshold to isoprenaline. There was no effect on ejection time, mean ejection rate or tension time index. Extremely high doses of (+)-propranolol slightly raised the isoprenaline dose ratio in intact dogs but not after vagal section. The arithmetic difference between the effects of equivalent doses of (±)-propranolol and (+)-propranolol was approximately constant. The findings suggest that (±)-propranolol reduces cardiac work by blocking the sympathetic drive to the heart at doses up to 0·2 mg/kg (the usual clinical dose range) and that direct depression of the mycardium only occurs at doses well above this.
Comparison of bromisoval and carbromal in the rat
Authors: Rauws A G 
Published: April 2011

Abstract
Distribution experiments in vitro and in vivo with bromisoval and carbromal have shown carbromal to be more lipophilic and cumulative in brain and fat tissue. The half-life of bromisoval in the rat is approximately 2·5 h, that of carbromal is longer and variable. Stimulation and inhibition experiments revealed that both drugs are metabolized and follow different patterns. Carbromal toxicity is enhanced by bromide treatment, whereas bromisoval toxicity is not. The results show that carbromal is more toxic than bromisoval for the rat.
The binding of salicylate to plasma protein from several animal species
Authors: Kucera J L , Bullock F J 
Published: April 2011

Abstract
A comparison has been made of the binding of salicylate to plasma from man, green monkey, rabbit, rat, dog, and guinea-pig. Since the total protein content of normal, citrated, pooled plasmas of these species was not identical, comparisons were made with samples adjusted to the same total protein concentration. The % binding to plasmas of 5·3% total protein at 50 μg of drug/ml was found to be: man, 72%; green monkey, 70%; guinea pig, 64%; rabbit, 64%; rat, 47%; dog, 45%. Results for 150 μg and 500 μg of salicylate/ml are also reported. The albumin: globulin ratio as determined by electrophoresis varied widely among the species. Fractionation of the plasmas and comparison of binding, using 3% solutions of the various albumin fractions in buffer, indicated that the low binding of dog and rat plasmas was due primarily to the low binding affinity of the albumins. Adequate characterization of plasma samples is needed when comparative binding studies are made.
Possible oestrogenic and anti-androgenic effects in rats treated with the oral hypoglycaemic agents tolbutamide and acetohexamide
Authors: Saad Samir Fahmy 
Published: April 2011

Abstract
Tolbutamide has an oestrogenic activity; when administered in four oral daily doses of 125, 250 and 500 mg/kg to ovariectomized young rats, it significantly increased their uterine weight. Tolbutamide, when administered in five oral daily doses to castrated young male rats, decreased the weight of the prostatic tissue; the effect was significant with a dose of 250 mg/kg. Acetohexamide in oral doses of 125, 250 and 500 mg/kg, had no significant effect either on the prostatic or the uterine weight.
Interaction between histamine and monoamine oxidase inhibitors
Authors: Allen G S , Rand M J 
Published: April 2011

Abstract
The monoamine oxidase inhibitors tranylcypromine, nialamide and iproniazid potentiated the actions of histamine on the blood pressure of the cat and on the tracheo-bronchial muscle of the guinea-pig. These findings may have relevance to side-effects of treatment with monoamine oxidase inhibitors.
Central and peripheral monoaminergic membrane-pump blockade by some addictive analgesics and antihistamines
Authors: Carlsson Arvid , Lindqvist Margit 
Published: April 2011

Abstract
The ability of various analgesics and antihistamines to block the amine-uptake mechanism (the so-named membrane pump) of central and peripheral monoamine-storing neurons was investigated in mice. Activities indicating such blockade were observed within both groups but did not seem to correlate with analgesic or antihistaminic activity. The antihistamine chlorpheniramine proved remarkably potent on central 5-hydroxytryptamine neurons.
Stabilization of oil-in-water emulsions by non-ionic detergents: the effect of polyoxyethylene chain length
Authors: Elworthy P H , Florence A T 
Published: April 2011

Abstract
The stability of emulsions of anisole and chlorobenzene in water has been estimated by following microscopically the size distribution of emulsions as a function of time. The effect of increasing the length of the polyoxyethylene glycol chain of the hexadecyl ether non-ionic stabilizers from three units to nine units was determined. Electrophoretic measurements indicated that the higher stability obtained on increasing the glycol chain length is not due to an increasing surface potential: it is ascribed to an entropic effect. Stability data are tabulated as rates of coalescence (s−1) and results are presented relating these rates to zeta-potential, surface concentration and polyoxyethylene chain length. The results are discussed qualitatively and compared with the results obtained with cetomacrogol 1000 (Elworthy & Florence, J. Pharm. Pharmac., 1967, 19, 140S).
Stabilization of oil-in-water emulsions by non-ionic detergents: electrical and entropic contributions to stability
Authors: Elworthy P H , Florence A T 
Published: April 2011

Abstract
Calculations of the attractive and repulsive forces between globules of anisole and chlorobenzene in the presence of non-ionic detergents of varying polyoxyethylene chain length are presented. The equations of the Derjaguin-Landau-Verwey-Overbeek theory are used and the effect on the attractive potential of the adsorption of stabilizer onto the particle is taken into account. The adsorbed film was found to increase the attractive forces between the particles, VA. In the previous paper (Elworthy & Florence, J. Pharm. Pharmac., 1969, 21, 70) it was shown that the electrical contribution to stability is a secondary stabilizing factor. More quantitative estimates of this contribution have been made. The entropic repulsion has been calculated using an equation of Ottewill & Walker. The energy-distance diagrams are discussed in the light of the experimental results presented in the previous paper.
The alkaloids of the leaves of Mitragyna inermis (Willd.) O. Kuntze
Authors: Shellard E J , Sarpong K 
Published: April 2011

Abstract
The leaves of Mitragyna inermis (Willd.) O. Kuntze have been examined for alkaloids and shown to contain routundifoline, isorotundifoline, rhynchophylline, isorhynchophylline, ciliaphylline, rhynchociline, speciophylline, a small amount of uncarine F, mitraciliatine and traces of a second indole alkaloid which appears to be of the corynanthine type. There is also a polar compound present, Dragendorff positive, which remains on the base line when subjected to thin-layer chromatography with the usual solvent systems used for the mitragyna alkaloids.
Kinetics of buccal absorption of some carboxylic acids and the correlation of the rate constants and n-heptane:aqueous phase partition coefficients
Authors: Beckett A H , Moffat A C 
Published: April 2011

Abstract
A simple model for the buccal absorption of some carboxylic acids is proposed. This model has been used, in conjunction with an analogue computer, to determine the rate constants of buccal absorption of ten acids from solutions of pH 4·0 using a single subject. These rate constants gave a positive correlation with the logarithms of previously determined n-neptane:0·1 N hydrochloric acid partition coefficients (correlation coefficient 0·89).
Potentiation of the effects of noradrenaline and of sympathetic stimulation of the perfused rat caudal artery by angiotensin
Authors: Nicholas T E 
Published: April 2011

Abstract
The isolated perfused caudal artery of the rat develops tachyphyllaxis rapidly to the direct constrictor action of angiotensin but not towards the potentiation of responses to submaximally effective periarterial stimulation or to noradrenaline. These potentiations persist in the presence of maximally effective concentrations of cocaine, are unaffected by increased sodium concentration and are enhanced by raised concentrations of calcium. Thus, angiotensin potentiates the effects of sympathetic nervous activity by an influence on the role of calcium in the contractile process. Hydrochlorothiazide did not affect arterial tone, the responses of the artery, or the potentiation to noradrenaline caused by angiotensin.
Potentiometric determination of sodium using a sodium ion responsive glass electrode
Authors: Pearson J T , Elstob Catherine M 
Published: April 2011

Abstract
A study to assess the feasibility of using a sodium ion responsive glass electrode in conjunction with a saturated calomel reference electrode to measure the sodium ion concentration of a wide range of electrolyte solutions used in clinical medicine has shown that the method is capable of giving results which are within acceptable limits. Direct measurement of solutions containing sodium chloride is possible by reference to a calibration based on the potential produced by the electrode pair as a function of pNa+ defined as -log10 sodium ion concentration. For the measurement of the sodium content of solutions of sodium salts of weak acids and mixed solutions of electrolytes and dextrose it is necessary to use a calibration carried out in a buffer system (0·5M triethanolamine + hydrochloric acid to pH 7) and to dilute the preparations with buffer before measurement. It is also necessary to buffer dextrose and sodium chloride injection before measurement due to the effect of decomposition of dextrose during sterilization causing a shift in pH which must be corrected before making a determination. The advantages of the potentiometric method over conventional flame photometric and titrimetric methods are discussed and a brief review of the literature given, to indicate the applications of specific ion electrodes.
The absorption, distribution and excretion of pentazocine in man after oral and intravenous administration
Authors: Beckett A H , Taylor J F , Kourounakis P 
Published: April 2011

Abstract
Gas-liquid chromatography is a sensitive technique for the analysis of pentazocine in biological samples. Dose for dose, the concentration in blood and the urinary excretion rate of pentazocine are much lower after oral administration than after intravenous administration. The recovery of the unchanged drug in faeces is low whether it is given by mouth or intravenously.
Structural specificity for inhibition of [14C]-5-hydroxytryptamine uptake by cerebral slices
Authors: Carlsson A 
Published: April 2011

Abstract
Cerebral slices were prepared from mice pretreated with reserpine and nialamide. The slices were incubated for 40 min at 37° in a Krebs-Henseleit solution equilibrated with 5% carbon dioxide in oxygen and containing [14C]-5-hydroxytryptamine. An uptake, dependent on energy metabolism and temperature, was observed. The uptake was blocked by tricyclic antidepressants, the order of activity being chlorimipramine &gt; imipramine &gt; desipramine. For 50% inhibition 0.03 μg/ml of chlorimipramine was required, when added to the suspension medium, or 1 mg/kg, when injected intraperitoneally 20 min beforehand. Comparison with earlier experiments using different experimental techniques appears to justify the conclusion that the evidence obtained represents the uptake mechanism of cerebral 5-hydroxytryptamine neurons.
Corticosteroid-collagen interaction in vitro: fibril formation from collagen solutions
Authors: Cooper D R , Kanfer I , Price C H 
Published: April 2011

Abstract
The disodium phosphate ester salts of betamethasone, prednisolone and hydrocortisone dissolved in a fibril initiating buffer accelerated the precipitation of fibrils from saline solutions of acid-soluble collagen at pH 7.0, when compared with the rate for the initiating buffer alone at the same pH. Without the initiating buffer these corticosteroids also precipitated collagen fibrils, but at a slower rate than when the initiating buffer was present. A relation has been found between the substitution of active groups on the basic steroid nucleus and the rate of collagen fibril formation from solution. Electron microscope examination of the fibrils precipitated by these corticosteroids showed that they corresponded to normal collagen fibrils in appearance and in having the characteristic repeat period of 60–70 nm.
Theoretical changes in drug distribution resulting from changes in binding to plasma proteins and to tissues
Authors: Curry Stephen H 
Published: April 2011

Abstract
Concentrations of chlorpromazine fluctuate in the plasma of dogs and man after intravenous doses. The possibility that the fluctuations could arise from movement of the drug between tissue and plasma stores is examined theoretically. Calculations show that small changes in protein binding of drugs in plasma and tissues could cause redistribution of highly bound drugs between tissues and plasma. Redistribution would be greatest after changes in tissue binding of highly bound drugs. Fluctuations in chlorpromazine concentrations could be caused in this way.
The effect of magnesium ions and Tris buffer on the uptake of cetyl trimethyl ammonium bromide by Escherichia coli
Authors: Salt W G , Wiseman David 
Published: April 2011

Abstract
The uptake of CTAB by E. coli from a glucose-free mineral salts medium occurs in two distinct phases. Increasing the magnesium ion content of the suspending medium emphasizes the diphasic nature of the isotherm. The primary phase is extended and the height of the “saturation” plateau of the secondary phase, as a function of CTAB uptake, is reduced. The CTAB uptake isotherm for E. coli suspended in water is not obviously diphasic and the maximum amount of CTAB taken up by the cells at “saturation” is less than that in medium. The height of this plateau is influenced by Tris buffer, an increase in the Tris concentration increasing the maximum CTAB uptake. A method for the rapid screening of uptake isotherms based on turbidity changes is also discussed.
Analysis of the action of m-tyrosine on blood pressure in the conscious rat: evidence for a central hypotensive effect
Authors: RUBENSON ALLAN 
Published: April 2011

Abstract
Mean arterial blood pressure was recorded through indwelling arterial catheters in conscious normotensive rats. dl-m-Tyrosine, 400 mg/kg, was given intraperitoneally alone and after pretreatment with two inhibitors of dopa decarboxylase [dl-α-hydrazino-α-methyl-β-(3,4-dihydroxyphenyl) propionic acid (MK 485) or N1-(dl-seryl)-N2-(2,3,4-trihydroxybenzyl)hydrazine (Ro 4–4602)]. dl-m-Tyrosine alone produced a hypertensive response, but after MK 485 it caused a significant lowering of blood pressure after 5–7 min and after Ro 4–4602 (400 + 200 mg/kg) it had no significant influence on blood pressure. The hypotensive response to dl-m-tyrosine was not influenced by the central dopamine receptor blocking agent spiroperidol (0·1 mg/kg) or by pretreatment with the tyrosine hydroxylase inhibitor H 44/68 (250 mg/kg). However, the depressor action could be completely inhibited after depletion of central catecholamines by α-methyl-m-tyrosine, 400 + 400 + 200 mg/kg, in combination with H 44/68, 250 mg/kg. Further, the depressor action was abolished by the dopamine β-hydroxylase inhibitor bis (4-methyl-1-homo-piperazinyl-thiocarbonyl) disulphide (FLA-63) 40 mg/kg. In correlative biochemical experiments the concentrations of the decarboxylation products of m-tyrosine were measured in brain and heart. dl-m-Tyrosine alone produced an accumulation of m-tyramine and m-octopamine in these tissues. MK 485 + m-tyrosine substantially reduced the levels of m-tyramine and m-octopamine in the heart, but their accumulation in brain was largely unaltered. The results suggest that when decarboxylation of dl-m-tyrosine occurs in both the central and peripheral nervous system, there is a pressor action. When decarboxylation occurs mainly in the central nervous system there is a hypotensive response which is associated with accumulation of decarboxylation products of m-tyrosine.
The effect of the histidine decarboxylase inhibitor brocresine (NSD-1055) on gastric acid secretion in rats
Authors: BECKER M , SEWING K-FR 
Published: April 2011

Abstract
The effect of the histidine decarboxylase inhibitor brocresine (NSD-1055) given by mouth, intraperitoneally or intravenously on tetragastrin-, histamine- and bethanechol-stimulated gastric acid secretion was examined in rats. Intravenous injection of brocresine slightly reduced the tetragastrin-stimulated secretion. Histamine-stimulated secretion was markedly increased by both intraperitoneal and intravenous injection of brocresine but it had no effect on the bethanechol-stimulated secretion. It was concluded that either histidine decarboxylase is not effectively inhibited by brocresine or any inhibition induced does not affect gastric acid secretion. The enhanced histamine-stimulated secretion points towards an inhibition of diamine oxidase by brocresine.
Effects of papaverine and eupaverin on calcium uptake by isolated sarcoplasmic vesicles
Authors: CARPENEDO F , TOSON G C , FURLANUT M , FERRARI M 
Published: April 2011

Abstract
Papaverine and eupaverin increase the rate of uptake of calcium by sarcoplasmic vesicles isolated from rabbit white skeletal muscle. The degree of activity of the above drugs is clearly affected by changes of ATP, oxalate and Ca2+ concentrations. The results are discussed in view of present knowledge about the effects of papaverine-like drugs upon muscular contraction.
The effect of detergent concentration on monomer activity in a non-ionic detergent solution
Authors: MACFARLANE C B , ELWORTHY P H , GYANE D O 
Published: April 2011

Abstract
The mono-octyl ether of hexaoxyethylene glycol has been synthesized and carefully purified using foam fractionation in the ultimate stages of the purification. Surface tension measurements of solutions of the detergent in water using a Wilhelmy plate indicate a continuing decrease in surface tension with increasing detergent concentration above the critical micellar concentration. Vapour pressure osmometry using the Mechrolab 302 substantiated the interpretation of the results in terms of the law of mass action.
The solubility of some compounds in hexadecylpolyoxyethylene monoethers, polyethylene glycols, water and hexane
Authors: CORBY T C , ELWORTHY P H 
Published: April 2011

Abstract
The solubilities of a series of compounds of varying polarity, i.e. decane, benzene, sulphadiazine, p-hydroxybenzoic acid, ethyl and butyl p-hydroxybenzoate and methyl anisate in cetomacrogol 1000 and hexadecyl heptaoxyethylene ether solutions, have been determined. A comparison of these results with the solubilities of these compounds in water, n-hexane and polyethylene glycol solutions gives some evidence on the mechanism of solubilization. The results show that the solubilization of these compounds is not adequately described solely on the basis of solubility into the separate regions of the micelle. The micellar solubility of the compounds was dependent on the hydrocarbon solubility and the presence of groups in the molecule which can form hydrogen bonds. Butyl paraben was found to have a higher solubility in 10% cetomacrogol solutions than either ethyl paraben or methyl anisate. The hydrophil–lipophil characteristics of the detergents with the polarity of the solubilizate molecule also affect solubilization. A non-polar molecule such as decane has a greater solubility in the more lipophilic detergent and the reverse is true of p-hydroxybenzoic acid.
Identification of the site of solubilization of various compounds by cetomacrogol
Authors: CORBY T C , ELWORTHY P H 
Published: April 2011

Abstract
Solubilization of some of the esters of p-hydroxybenzoic acid by cetomacrogol 1000 solutions has been investigated by ultraviolet spectrophotometry, nuclear magnetic resonance spectrometry and viscometry to provide evidence on the environment of each part of the solubilizate molecule as well as the detergent molecule. Hydration of the micelles calculated from the viscometry results, gave further evidence on the site of solubilization of the compounds. On the basis of these results and solubility results published previously it is suggested that the compounds are solubilized as follows: p-Hydroxybenzoic acid is wholly solubilized deep in the oxyethylene layer of the micelle. Ethyl p-hydroxybenzoate is solubilized mostly in the oxyethylene layer and is situated adjacent to the core: some solubilization occurs within the core. Butyl p-hydroxybenzoate is solubilized mainly at the oxyethylene-hydrocarbon junction, the phenyl ring in the oxyethylene layer and the butyl chain in the core: some solubilizate is wholly present in the core. Methyl p-methoxybenzoate: most of the compound is dissolved in the micellar core, but some is also present in the oxyethylene layer. Benzene is solubilized in a similar manner to methyl p-methoxybenzoate.
The adsorption of crystal violet by kaolin
Authors: ARMSTRONG N A , CLARKE C D 
Published: April 2011

Abstract
The uptake of crystal violet on kaolin was examined over a pH range of 2·5 to 9·5, adsorption showing an increase with pH. The attainment of equilibrium between adsorbate and adsorbent is shown to be a two-stage process, the first stage being synchronous with the release of magnesium from the kaolin lattice. Evidence is presented that the major mechanism of adsorption is by electrostatic charges arising from cation replacement in the clay lattice, and that charges arising from the amphoteric nature of the aluminium atom of kaolin make little contribution to the overall adsorptive process.