Showing papers by "University of Aberdeen published in 1975"
TL;DR: The evidence is based on the determination of the amino acid sequence of natural enkephalin by the dansyl–Edman procedure and by mass spectrometry followed by synthesis and comparison of the natural and synthetic peptides.
Abstract: Enkephalin, a natural ligand for opiate receptors is composed of the pentapepides H-Tyr-Gly-Gly-Phe-Met-OH and H-Tyr-Gly-Gly-Phe-Leu-OH. The evidence is based on the determination of the amino acid sequence of natural enkephalin by the dansyl-Edman procedure and by mass spectrometry followed by synthesis and comparison of the natural and synthetic peptides.
3,580 citations
TL;DR: It is suggested that the compound isolated in this investigation forms part of a central pain suppressive system and may also have a wider neurochemical role in the brain.
961 citations
TL;DR: The fact that the agonist effects of drugs with dual agonist and antagonist action show little or no dependence on concentration, makes the mouse vas deferens particularly suitable for the assay of antagonist activity.
Abstract: 1. Morphine inhibits the electrically evoked (0.1-0.15 Hz, 1 ms) contractions of the longitudinal muscle of the mouse vas deferens but not of the rabbit, guinea-pig, rat, cat, hamster or gerbil. This effect is stereospecific and is antagonized by naloxone or naltrexone. 2. Normorphine is equiactive with morphine but its effects are more rapid in onset and decline. 3. In the mouse vas deferens, the resting outflow of tritium-labelled catecholamines is unaffected by morphine. The electrically evoked outflow is depressed by morphine or normorphine in a dose-dependent manner. The ID50 for inhibition of contraction and for depression of outflow is 0.5 muM. 4. The relative agonist potencies of compounds without antagonist component (codeine, pethidine, morphine, normorphine, heroin, levorphanol, Ba-20227, etorphine) show good correlation with the relative agonist potencies determined in the guinea-pig ileum and for analgesia in man. 5. For compounds with dual agonist and antagonist properties, the dose-response curves for agonist activity are shallow. When the lowest concentrations giving a depression of the contraction of the mouse vas deferens are used, a good correlation is obtained with the guinea-pig ileum. 6. The relative antagonist potencies of naloxone, nalorphine, levallorphan, and cyclazocine agree well with those obtained in the guinea-pig ileum; these, in turn, correlate well with the values obtained in the morphine-dependent monkey. 7. The fact that the agonist effects of drugs with dual agonist and antagonist action show little or no dependence on concentration, makes the mouse vas deferens particularly suitable for the assay of assay of antagonist activity. 8. As an assay preparation, the mouse vas deferens is less robust and consistent in its responses than the guinea-pig ileum.
402 citations
TL;DR: A circuit for detecting timing errors between a binary signal and a local clock pulse generator and logical control signals for the clock are derived.
Abstract: A circuit for detecting timing errors between a binary signal and a local clock pulse generator is described. Three binary samples are compared and logical control signals for the clock are derived.
328 citations
TL;DR: Interactions between endogenous enkephalin and exogenous opiate at the opiate receptor are discussed as a possible basis of tolerance and dependence caused by chronic administration of opiates.
263 citations
TL;DR: It is suggested that the peptide extracted from the pig brain may have a wide neurophysiological role in the brain and possibly in other tissues.
233 citations
TL;DR: Four benzomorphans which have potent antinociceptive activity in the hot‐plate and writhing tests in the mouse but do not suppress or precipitate withdrawal symptoms in the morphine‐dependent monkey, have been examined for their pharmacological actions in the guinea‐pig ileum and mouse vas deferens.
Abstract: 1 Four benzomorphans which have potent antinociceptive activity in the hot-plate and writhing tests in the mouse but do not suppress or precipitate withdrawal symptoms in the morphine-dependent monkey, have been examined for their pharmacological actions in the guinea-pig ileum and mouse vas deferens 2 In the guinea-pig ileum their agonist potencies are 15 to 400 times greater than that of normorphine of morphine whereas in the mouse vas deferens their potencies relative to morphine are 03 to 100 They exhibit no antagonist activity in either preparation Benzomorphans which substitute for morphine in the morphine-dependent monkey do not show such differences between their relative potencies in the guinea-pig ileum and mouse vas diferens 3 The relative potencies of the four benzomorphans to inhibit stereospecific [3H]-dihydromorphine binding by membrane fragments from rat brain, are more closely related to their relative agonist potencies in the mouse vas deferens than to those found in the guinea-pig ileum 4 In order to antagonize the agonist actions of these benzomorphans, naloxone is required in concentrations which are 3 to 7 times higher than those needed for the antagonism of normorphine or morphine or of benzomorphans which suppress abstinence in morphine-dependent monkeys 5 It may be possible to use the three assays, namely, ratio of relative agonist potency in mouse vas deferens to that in guinea-pig ileum, ratio of relative agonist potency to relative affinity to opiate receptors and the concentration of nalozone required for antagonism, for the prediction of the potential of new compounds to produce physical dependence
182 citations
167 citations
TL;DR: This article investigated the frequencies with which white and black subjects use different facial features when describing faces and found that black and white subjects did differ in their descriptions of faces, which was interpreted as reflecting differences in attention to the various aspects of facial detail.
Abstract: A previous experiment by Shepherd, Deregowski and Ellis (1974) showed that white subjects are better at remembering white faces than black faces, and that black subjects are superior at recognizing black compared with white faces. The present experiment was designed to investigate the frequencies with which white and black subjects use different facial features when describing faces. It was found that black and white subjects did differ in their descriptions of faces, which was interpreted as reflecting differences in attention to the various aspects of facial detail. The difference in attention deployment is suggested as a possible basis for the earlier reported differences in recognition memory for white and black faces by white and black subjects.
159 citations
TL;DR: In this paper, two experiments concerning the efficiency of the Photo-fit Kit for recalling faces are reported. And the first of these tested subjects' ability to reconstruct photographs of faces made up of features randomly selected from the Kit, though both were far from perfect.
Abstract: Two experiments concerning the efficiency of the Photo-fit Kit for recalling faces are reported. The first of these tested subjects' ability to reconstruct photographs of faces made up of features randomly selected from the Kit. Two presentation procedures were examined: either the stimulus face was present throughout the reconstruction, or it was reconstructed from memory. The face present condition produced better reconstructions than did the memory condition, though both were far from perfect. Subjects (encoders) who had performed relatively well or badly on the memory condition in Expt. I were used in Expt. II which was concerned with the ease with which Photo-fit reconstructions of a photographed real face could be identified (decoded) by other subjects. The overall success rate was quite low, but the reconstructions of good encoders were more easily recognized than were those of poor encoder subjects.
137 citations
TL;DR: In this paper, a model is constructed and estimated for the attendances of four English First Division clubs and the possibility of a common law-like relationship is examined and account is taken of common cross-sectional influences in order to raise the efficiency of the estimates.
Abstract: SUMMARY Little quantitative work has so far appeared in the growing literature on professional sports. In this paper a model is constructed and estimated for the attendances of four English First Division clubs. The possibility of a common law-like relationship is examined and account is taken of common cross-sectional influences in order to raise the efficiency of the estimates.
TL;DR: The chapter discusses the energy coupling in microbial transport data and discusses pattern forming out of the interactions between the various transport systems, and their function and regulation.
Abstract: Publisher Summary The chapter discusses the energy coupling in microbial transport data The mechanism of energy coupling, a prerequisite where a substrate is concentrated within the membrane-bounded volume, has been incompletely understood and only hinted at in the various models that have been put forward in an effort to describe the transport system The particular excitement of current studies lies in the new, or at least, developing and understanding of the molecular nature of the cellular mechanisms coupling the redox and chemical energies of metabolism to the transport and intracellular accumulation of nutrients The chapter also discusses pattern forming out of the interactions between the various transport systems, and their function and regulation In the simpler study of energy-coupling mechanisms, it has been this attempt to trace the outlines of a logical and integrated pattern that has directed the choice of papers and the form of discussion in the chapter As such, no pretence can be made of a comprehensive coverage, and perhaps a personal bias may be all too obvious to some readers It is the earnest hope of the author, however, that any such criticisms may be more than fully compensated for by an increased level of comprehension of the facts and their relevance, in an area of study that has too often in the past owed more to the imagination of the model builder than to the realism of the experimenter
TL;DR: Pictures of upright and inverted faces were unilaterally presented in either the left or right visual field and recognition performance was found to be superior for faces falling in the left visual field regardless of orientation.
TL;DR: It is assumed that naloxone antagonises the action of enkephalin which has been shown to be present in the guinea-pig ileum and recommended to establish the stereospecificity of an antagonist action in order to exclude pharmacological effects not due to interaction with opiate receptors.
TL;DR: There is strong evidence to support the contention that calcium ion influx is involved both in the release of acetylcholine and of noradrenaline but ion-exchange processes at the level of the vesicle not necessarily directly involving calcium have been proposed and the concept of regulation of release through changes in the activity of an adenosine triphos-phatase (ATPase) has been invoked.
Abstract: WHEN a wave of depolarisation spreads down an axon and invades the nerve terminals a number of events rapidly occur and it is difficult to establish the one ultimately res ponsible for the release of neurotransmitter. There is strong evidence to support the contention that calcium ion influx is involved both in the release of acetylcholine1 and of noradrenaline2 but ion-exchange processes at the level of the vesicle not necessarily directly involving calcium have been proposed3 and the concept of regulation of release through changes in the activity of an adenosine triphos-phatase (ATPase) has also been invoked4,5. This paper is concerned with the last possibility. Following the inward movement of sodium ions the inward movement of calcium ions to the enzyme on the inner edge of the nerve terminal membrane would be expected to inhibit the activity of sodium potassium-activated magnesium-dependent ATPase (Na,K-ATPase)6. Sodium depletion or the addition of ouabain to preparations in vitro would also be expected to inhibit Na K-ATPase activity. These three conditions of enzyme inhibition have all been shown to result in increased acetylcholine release4,5.
TL;DR: A 1200 calorie diet or cyclopenthiazide with potassium was given to two groups of 51 high weight gain primigravidae and baby weight and there was no difference in the development of pre‐eclampsia.
TL;DR: Nereis diversicolor is an important food species for vertebrate predators in the Ythan Estuary, Scotland but those in the lower half of the shore are more numerous, heavier for a given size and reproduce earlier in the season than animals in the top half ofThe shore.
TL;DR: Electrical field stimulation of either the cat isolated nictitating membrane or the guinea‐pig ileum myenteric plexus‐longitudinal muscle preparation caused the release of noradrenaline into the bathing medium.
Abstract: 1. Electrical field stimulation of either the cat isolated nictitating membrane or the guinea-pig ileum myenteric plexus-longitudinal muscle preparation caused the release of noradrenaline into the bathing medium. 2. In the cat nictitating membrane, the output per pulse of noradrenaline was constant at frequencies of stimulation from 0.5 to 15 Hz. In the guinea-pig myenteric plexus preparation the output per pulse of noradrenaline increased as the frequency of stimulation was increased from 2 to 16 Hz. 3. Phenoxybenzamine (29.3 muM) caused a marked increase in the noradrenaline output from both the cat nictitating membrane and guinea-pig myenteric plexus preparations. 4. Morphine (0.13-8 muM) inhibited the contractions of the cat nictitating membrane caused by electrical stimulation. This effect was greater at low (1Hz) than at high (15Hz) frequencies of stimulat The site of action is at the nerve-smooth muscle junction. 5. The action of narcotic analgesic drugs on the cat nictitating membrane showed stereospecificity. Naloxone (0.1 muM) reversed the inhibition caused by normorphine (3.2 muM). 6. Morphine (3 muM) reduced the noradrenaline output from the cat nictitating membrane stimulated at 1 Hz but not at 15 Hz. At 1 Hz, the inhibition of noradrenaline output by normorphine (muM) was reversed by naloxone (0.25 muM). 7. Morphine (1.5 muM) did not alter the noradrenaline output from the guinea-pig myenteric plexus preparation stimulated at 2 or 16 Hz.
TL;DR: The purpose of this article is to review the current understanding in both fields of antioestrogenism and modify rather than counteract oestrogen effects.
Abstract: Antioestrogens are a group of compounds which are at present attracting much attention both in scientific research and in clinical practice. The purpose of this article is to review the current understanding in both fields. Definitions of an antioestrogen. In the broadest sense, an antioestrogen is a substance which counteracts the activity of oestrogens (Terenius, 1974). For the purpose of this review, however, the definition will be restricted by the following considerations. (a) Direct eflect on oestrogen activity. Some substances do not counteract oestrogens directly but block subsequent events set in train by oestrogens. Hence substances which alter oestrogen response by interfering with protein or RNA synthesis in a target cell or with oestrogen metabolism in, say, the liver are not considered as antioestrogens in the context of this article. Neither is a substance which suppresses oestrogen secretion considered as an antioestrogen. Certain substances like androgens and progestogens can modify rather than counteract oestrogen effects. These substances do not interfere with oestrogen uptake by a target cell but modify the oestrogen response by stimulating other cell components (Terenius & Ljungkvist, 1972). (b) Blocking of oestrogen receptors. Antioestrogens have an affinity for the protein oestrogen-receptors in the target cell cytoplasm. Terenius (1970) has divided antioestrogens into two categories depending on the duration of receptor retention. The first group of antioestrogens is effective following systemic administration and has a sustained effect in blocking oestrogen stimulation : the second group is most effective when given locally, appears to be only transiently attached to the receptor but impedes the response to other oestrogens like oestradiol-17P (see Table 1).
TL;DR: In this paper, the substituent effects (S values) of CX bonds on the frequencies of CH bonds in cis, trans or α positions are obtained either directly from the CH2CHX isolated frequencies (X = Cl, Br) or indirectly from those of the X3 and X2 species.
TL;DR: Macoma balthica (L.) is an important food species for many vertebrate predators on the Ythan Estuary and in the intensive study area had a maximum density of about 6000/m 2 after spat settlement.
TL;DR: In this paper, it is shown that some of the potentially troublesome harmonic components can be neutralized by suitable cho... and it is also shown that the vibration of the teeth by the teeth in a simple epicyclic gear system is considered.
Abstract: Excitation of vibration by the teeth in a simple epicyclic gear system is considered, and it is shown that some of the potentially troublesome harmonic components can be neutralized by suitable cho...
TL;DR: In this article, a mixture of CaO and colloidal silica with and without γ-Al2O3, CaO, and alkali-bearing Al 2O3-SiO2 gels were treated hydrothermally at 90°C or 120°C for 4 hours to 4 weeks.
TL;DR: In this paper, a complete set of anharmonicity constants x ij is obtained and the general harmonic force field determined from frequencies, frequency shifts and new values of Coriolis coefficient ξ 3,5 and of centrifugal distortion coefficients.
TL;DR: In this article, roughly trilete shaped (plan) predominantly sub-Upper Cretaceous trough systems extending north-south for more than 1200 km are described for the North Sea Basin.
TL;DR: In this article, a stable bed feature is arrived at when the two effects are so balanced that the transport rate of bed load is the same in the suction zone as elsewhere.
Abstract: Examination of the stream bed over a water intake buried beneath it revealed a scoured hole with a dune downstream. Laboratory experiments result in the same kind of feature, providing the bed material is too penetrative to ripple. Theoretical treatment based on momentum changes in the suction zone and limited to two dimensions reproduces, with reasonable success, the behavior of beds of medium sand in a narrow laboratory flume. Grains move faster in the suction zone than elsewhere and their increased reluctance to settle is offset by increased stability of the stationary grains. A stable bed feature is arrived at when these two effects are so balanced that the transport rate of bed load is the same in the suction zone as elsewhere.
TL;DR: It was concluded that the lateral forebrain area is critically and specifically involved in the visual learning of imprinting being necessary for the discrimination of, but not for approach responsiveness to, imprinting objects.
Abstract: Newly hatched domestic chicks were subjected to bilateral aspiration lesions of the anterior, dorsal, posterior or lateral regions of the forebrain and then were reared separately with one of two types of imprinting object. Between 3 and 10 days later they were tested for imprinting, pecking accuracy, visual looming and auditory startle responses. Lateral and dorsal lesion groups differed from a control group in the number of successful discriminations of their imprinting object and the lateral group was not significantly different from a random expectancy. All groups were impaired in pecking accuracy but the lateral group was the most severely affected. Looming responses and post startle freezing behaviour were reduced only in the posterior and dorsal groups which were also the least responsive in the imprinting tests. It was concluded that the lateral forebrain area is critically and specifically involved in the visual learning of imprinting being necessary for the discrimination of, but not for approach responsiveness to, imprinting objects.
TL;DR: In seventy‐eight patients with alopecia areata, the incidence of auto‐antibodies to smooth muscle was greater than that in an age and sex matched control population.
Abstract: SUMMARY
In seventy-eight patients with alopecia areata, the incidence of auto-antibodies to smooth muscle was greater than that in an age and sex matched control population.
TL;DR: It is suggested that, like soil fungi, the germination of spores of phylloplane fungi may be nutrient-dependent, or independent with respect to exogenous nutrients.
Abstract: Conidia of different isolates of Botrytis cinerea Pers. ex Fr. varied widely in ability to germinate in water. Sugars and amino acids were added at concentrations similar to natural levels on leaf surfaces. To a limited extent simple sugars promoted germination. Fructose was most effective whilst sucrose was least effective. Amino acids stimulated germination with the exception of taurine and lysine. Lysine reduced the stimulatory effect of a mixture of amino acids. Germination of conidia was only increased by an inorganic nitrogen source, ammonium salts or by a mixture of mineral salts, when glucose was present. Growth factors, yeast extract, gibberellic acid and kinetin had no effect on germination but indole-acetic acid caused a small stimulation. Abscisic acid depressed germination. It is suggested that, like soil fungi, the germination of spores of phylloplane fungi may be nutrient-dependent, or independent with respect to exogenous nutrients. Poor in vivo germination of B. cinerea may be associated with competition.
TL;DR: The results indicate that bacteria on leaf surfaces, by utilizing nutrients derived both from conidia and from exogenous sources, would adversely affect germination of conidia.
Abstract: There was a large initial loss of 14C from labelled Botrytis cinerea conidia immediately on suspension in water. The presence of cells of a leaf surface bacterium (Pseudomonas sp., isolate 14) did not appreciately increase the rate of loss of substrates from conidia. A proportion of the leaked 14C was taken up by bacteria causing a rapid decline in the amount of 14C in solution. Less than 2% of 14C derived from conidia could be recovered from cells of bacteria. The addition of bacteria to conidia caused a reduction in the total amount of released 14CO2. Results indicated that a substantial proportion of the 14C taken up by bacteria was released as 14CO2 and tha amount of 14CO2 from conidia was reduced in the presence of bacteria. Bacteria removed over 85% of added 14C glutamine when grown in solution whilst under similar conditions conidia removed less than 10%. Most of the glutamine had taken taken up by bacteria in the first 3 h and was accompanied by a high rate of 14CO2 evolution. The results indicate that bacteria on leaf surfaces, by utilizing nutrients derived both from conidia and from exogenous sources, would adversely affect germination of conidia.