Showing papers by "Vanderbilt University published in 1968"
TL;DR: The evidence presented supports the hypothesis that the positive inotropic response to the catecholamines is mediated by cyclic AMP.
Abstract: Cyclic AMP (adenosine 3',5'-monophosphate or cyclic adenylate) has now been established as a second messenger mediating many of the effects of a variety of hormones. Several of the metabolic effects mediated by cyclic AMP are discussed, and it is suggested that certain other ("functional" or "mechanical") hormonal effects may be similarly mediated. In particular, the evidence presented supports the hypothesis that the positive inotropic response to the catecholamines is mediated by cyclic AMP. Although knowledge of the biological role of cyclic AMP has not been widely applied clinically, sufficient knowledge has now accumulated to make research in this area desirable.
980 citations
TL;DR: In combination, epinephrine and caffeine acted synergistically, producing large increases in cyclic AMP, indicating that, as in other systems, the catecholamines act to stimulate adenyl cyclase and the methyl xanthines act to inhibit the cyclic nucleotide phosphodiesterase.
533 citations
TL;DR: Kinetic studies indicate that the interactions between the polymerase-DNA structure and the deoxynucleoside triphosphates and Mg++ or Mn++ are complex, and there are only one or two sites of initiation on helical linear DNA molecules, and that reinitiation on a synthetic complex does not occur.
389 citations
TL;DR: Prostaglandin E1 lowered cyclic AMP levels in isolated fat cells very rapidly, and was effective against adrenocorticotropic hormone, glucagon, and thyroid-stimulating hormone as well as the catecholamines.
335 citations
TL;DR: The hypothesis is advanced that changes in cyclic AMP levels may be partly responsible for the alterations in liver metabolism caused by insulin and diabetes.
311 citations
281 citations
TL;DR: Cooper's ligament urethrovesical suspension for stress incontinence was first used in 1958 and the series now comprises 143 cases; the most challenging complication was enterocele, occurring in 7.6 per cent of cases.
270 citations
TL;DR: Sympathetic nervous activity, leading to the intrahepatic release of catecholamine, may also play an important role in increasing glucose output and lactate uptake by the liver, particularly during exercise or hypoglycemia.
242 citations
TL;DR: This paper identified replicable factors in the conceptualization of the deity from both areas of previous research and included adjectives of possible applicability to the concept of "God" were included in a hierarchical factor analysis.
Abstract: Previous studies have identified several dimensions reflecting the concepts used by religious people in describing God. Semantic Differential research has also found adjectival factors which apply to numerous concepts, including that of God. The present study sought to identify replicable factors in the conceptualization of the deity from both areas of previous research. Adjectives of possible applicability to the concept of "God" were included in a hierarchical factor analysis. A general factor of the Traditional Christian concept appeared along with factors previously identified (Deisticness, Eternality, Evaluation, Kindliness, Omni-ness, and Wrathfulness) as well as several new dimensions (e.g., Irrelevancy and Potently Passive). The internal consistency of each scale resulting from the factor analysis was determined in another sample of subjects and indicated that most of the factors could be easily measured.
169 citations
TL;DR: The proteolytic enzyme, clostridiopeptidase B (clostripain), from Clostridium histolyticum culture filtrates has been purified to apparent homogeneity as judged by ultracentrifugation, electrophoresis in polyacrylamide gels, immunodiffusion, and immunoelectrophoreis.
164 citations
TL;DR: Drugs and other compounds capable of causing sustained trembling are rare; in a survey of ten thousand compounds Everett et al. found less than ten with this property.
Abstract: DRUGS and other compounds capable of causing sustained trembling are rare; in a survey of ten thousand compounds Everett et al. found less than ten with this property1. One of the best known is tremorine (1,4-dipyrrolidine-2-butyne) which is converted into a more active compound, oxotremorine2, by body tissues. Various synthetic amino alcohols also stimulate prolonged tremors, but their mechanism of action differs from that of tremorine and other more familiar compounds3.
TL;DR: In this article, half the subjects received a first bid favorable to themselves from the opponent, while the other half received an unfavorable first bid, and favorable bids led to higher demands, both in counterbids and in contract accepted, among incompletely informed subjects.
TL;DR: The absence of any effect of glucagon on glucose or lactate formation from fructose suggests that cyclic AMP does not produce any significant effect on reactions between triose-P and glucose or on the conversion of P-pyruvate to pyruVate, and gluconeogenesis appears to be as sensitive as glycogenolysis to stimulation by glucagon, catecholamines and cyclicAMP.
TL;DR: The three-dimensional molecular structure of coenzyme B 12 (59-deoxyadenosylcobalamin) has been determined by X-ray diffraction as mentioned in this paper.
Abstract: The three-dimensional molecular structure of coenzyme B 12 (59-deoxyadenosylcobalamin) has been determined by X-ray diffraction. The crystals, as grown from an acetone-water solution and photographed wet, are orthorhombic (space group P 2 1 2 1 2 1 ) with a = 27·93, b = 21·73 and c = 15·34 A. Four coenzyme molecules (C 72 H 100 O 17 N 18 PCo) and about 68 water molecules make up the unit cell. 3068 Bragg reflexions, extending to a spacing of 0·9 A, were measured with the crystals in contact with their mother liquor. The intensities were estimated visually from Weissenberg films taken with Cu Kα radiation. The cobalt atoms were easily located from the Patterson synthesis. The structure was solved in three steps, using first cobalt alone, then cobalt and 53 light atoms, and in the third approximation, 106 atoms, which included nearly the full asymmetric unit, except for water and hydrogen. Refinement of the atomic coordinates was accomplished initially by calculation of difference syntheses and finally by differential synthesis. The atomic positions have standard deviations of about 0·04 A. The conformation of the molecule is very similar to cyanocobalamin. The principal differences are in the orientation of the acetamide and propionamide side chains. Factors which influence the conformation of the corrin nucleus are analysed by comparing several corrinoids of known structure. Features of the molecule which have been examined in detail include the pucker in the pyrroline rings, the bend in the corrin macrocycle, the conformation of the nucleotide and nucleoside moieties and the orientation of the deoxyadenosine moiety with respect to the corrin nucleus. The packing of the molecules and the hydrogen bonding is discussed and compared with that found in the wet and dry vitamin B 12 crystals. Each coenzyme molecule participates in 18 direct intermolecular hydrogen bonds.
TL;DR: It was concluded that the rapid phase of insulin uptake may be the hormone-cell interaction which is necessary for the action of insulin to be manifest, and a study of the factors which influence this process may lead to a better understanding of the mechanism of hormone action.
TL;DR: Analysis of subcellular fractions from Ehrlich ascites tumor cells indicated that most of the neuraminidase of these cells is present in the fraction containing lysosomes and mitochondria, and metal is probably involved in the action of the enzyme.
TL;DR: The results indicate that the mechanism of the (Na + + K + )-dependent ATPase is likely to be similar in most animal species and tissues.
TL;DR: Two investigations of the relationship between “worry” and “emotionality” (E), components of test anxiety, and performance expectancy are reported and W was found to be negatively related to expectancy.
Abstract: Two investigations of the relationship between “worry” (W) and “emotionality” (E), components of test anxiety, and performance expectancy are reported. Undergraduate and graduate students responded...
TL;DR: The results of the present studies are consistent with the views that the central action of amphetamine requires an uninterrupted synthesis of brain norepinphrine whereas a rapid release of norepinephrine from its storage sites is essential for the behavioral stimulation elicited by tetrabenazine in DMI pretreated rats.
Abstract: The relative role of storage and synthesis of brain norepinephrine in the psychomotor stimulation evoked by amphetamine or by desipramine and tetrabenazine has been investigated. The blockade of norepinephrine synthesis by the tyrosine hydroxylase inhibitor α-MT abolishes the central stimulatory action of amphetamine but not that evoked by tetrabenazine in DMI pretreated rats. In contrast, depletion of norepinephrine by α-MMT prevents the central stimulation evoked by the DMI-tetrabenazine combination but not that elicited by amphetamine. The α-methylated tyrosine derivatives do not interfere with either the metabolism of amphetamine and DMI or their entry into the brain. The results of the present studies, thus, are consistent with the views that the central action of amphetamine requires an uninterrupted synthesis of brain norepinphrine whereas a rapid release of norepinephrine from its storage sites is essential for the behavioral stimulation elicited by tetrabenazine in DMI pretreated rats.
TL;DR: It is suggested that the adrenal cell suspension might prove to be a versatile tool in adrenal physiology, and efficient in converting exogenous precursors into corticosterone.
Abstract: A method of preparation of a rat adrenal cell suspension is described. The adrenal cell suspension is much more sensitive to the steroidogenic action of ACTH than are adrenal slices or homogenates. The adrenal cell suspension is also efficient in converting exogenous precursors into corticosterone. It is suggested that the adrenal cell suspension might prove to be a versatile tool in adrenal physiology. (Endocrinology 82: 1053, 1968)
TL;DR: The glucose transport and adenyl cyclase systems are not grossly affected by trypsin, indicating that the insulin effector system is a separate entity, and the activity of the system is one of the highest known.
Abstract: Mediated (nonactive) transport of glucose in mammalian cells is characterized by saturation kinetics, stereospecificity, sensitivity to inhibition by phlorizin and certain sulfhydryl-blocking agents, a temperature coefficient of about 2, an inability to utilize metabolic energy, and countertransport. Countertransport can be explained by the development of carrier gradients in the cell membrane and provides the best evidence for carrier mobility. Efforts to identify and isolate chemical components of the transport system, have not been successful. Transport among different types of mammalian cells shows a wide range of activities (Vmax values differ by three or more orders of magnitude) and different sensitivities to hormones. Glucose enters the liver cell by mediated transport, as shown by a difference in the penetration rates of D- and L-glucose and sensitivity to phlorizin. The activity of the system is one of the highest known. Transport in muscle is the most important rate-controlling step for glucose utilization and is strongly accelerated by hypoxia, work, and insulin. The effect of work or insulin is strongly inhibited by metabolism, of fatty acids. Insulin also stimulates glucose transport in adipose tissue. Using isolated fat cells, it could be shown that insulin is rapidly bound to sites on the cell surface. The effect is lost within a few minutes after the exogenous hormone is removed. The bound insulin is not released as such, but is metabolized to unknown products. Binding is prevented by preexposure of cells to maleimide, which presumably blocks certain sulfhydryl groups at or near the insulin-binding site. Pretreatment with insulin protects against maleimide. Digestion of the cell with trypsin eliminates the acceleration of glucose transport and the inhibition of lipolysis by insulin. The glucose transport and adenyl cyclase systems are not grossly affected by trypsin, indicating that the insulin effector system is a separate entity.
TL;DR: The lipid bilayer model may prove to be a useful tool for the isolation and characterization of membrane proteins that may function as carriers, and suggest that sugar transport involves membrane constituents other than lipids.
TL;DR: The broad specificity of the enzyme toward the nucleotides tested suggests that it may play a key role in the degradation of intermediates in the lysosomal catabolism of nucleic acids and their components.
TL;DR: Evidence is presented that, when proteolytic modification is avoided, two distinct forms of yeast hexokinase can be demonstrated, with different catalytic and chemical properties.
Abstract: In a previous symposium of this Academy on multiple molecular forms of enzymes, a paper from this laboratory was presented (Kaji et al., 1961), in which multiple forms of yeast hexokinase were described. Since that time, it has been found that most, if not all, of these forms were derived by the action of a protease acting during the course of the preparation. In the present paper, the nature of this modification process is described, and the chemical, physical, and catalytic properties of unmodified and modified enzyme are summarized. Evidence is presented that, when proteolytic modification is avoided, two distinct forms of yeast hexokinase can be demonstrated, with different catalytic and chemical properties. The method for preparing these unmodified forms has been described elsewhere (Schulze et al., 1967). Similar results have been obthined independently in Barnard's laboratory (Lazarus et al., 1966 and Derechin et al., 1966).
TL;DR: The metabolism of hexobarbital by the isolated perfused rat liver was reduced after intoxication with CCl 4 and may have been responsible, in part, for the enhanced action of the barbiturate.
TL;DR: In this paper, the effect of nuclear structure details on pick-up and stripping form factors is investigated and an approximate method is set up in which the form factor emerges as the solution of an inhomogeneous differential equation.
TL;DR: The proposition that the anxiety scales and the LC scale are measuring conceptually separate variables which correlate with each other and that this correlation is not due to a hidden anxiety factor within the locus of control scale is supported.
Abstract: Several recent studies have reported significant relationships between various measures of general anxiety, test anxiety, and the locus of control scale (LC). Watson (1967) concluded that the correlation between locus of control and anxiety supports Mandler and Watson's (1966) hypothesis that actual or appraised lack of control (high external locus of control) produces anxiety. In order to determine whether there exists an anxiety factor within the locus of control scale, the Manifest Anxiety Scale (MAS), the Test Anxiety Scale (TAS), and the LC scale were administered to two samples of introductory psychology students at Vanderbilt University (N, = 323; Nq = 303). In an item analysis every item on the LC scale answered in exteral locus of control direction correlated postively with total score (high anxiety) on the MAS and TAS. However, the correlation of only 3 items from the LC scale actually reached significance ( p < .05) with the TAS and MAS in both samples (the significant IS ranged from . I 2 to .34). Total scores on the LC scale and the MAS were significantly correlated in both samples (sl = .40, rz = .30; p < .01). The LC scale and the TAS were also significantly correlated (sl = .22, r:! = .21; p < .01). A factor analysis using varimax rotation demonstrated that these significant correlations could not be explained in terms of an anxiety factor composed of highly correlated individual items on the LC scale which, when removed, would reduce the degree of relationship between the anxiety scales and the remaining locus of control items. These findings support the proposition that the anxiety scales and the LC scale are measuring conceptually separate variables which correlate with each other and that this correlation is not due to a hidden anxiety factor within the locus of control scale. A feeling of lack of control over the environment and the outcome of one's actions is associated with anxiety. Whether this appraised lack of control produces anxiety, or vice versa, cannot, of course, be determined from correlational studies of this type.
TL;DR: It is suggested that ChAc activity is a more reliable index of functional differentiation than is AChE and that the initial increase in A cholinesterase activity may be associated with some function other than synaptic transmission.
Abstract: Microchemical procedures were employed for the quantitative assay of acetylcholinesterase (AChE) and choline acetyltransferase (ChAc) activity in the brachial spinal cord of chick embryos from 3.5 to 21 days' incubation. The activity of AChE increased nearly 10-fold during the 60-hour period from stage 22 (3.5 days) to stage 30 (6.0 days). The level of AChE at six days was essentially the same as that at hatching. During the intervening period, the level of AChE activity remained unchanged with the exception of minor transient peaks at days 7, 13, and 18. The activity of ChAc increased 22-fold during the developmental period studied. The onto-genetic pattern was characterized by two periods of rapid increase in acitvity. From stage 23 (3.75 days) to stage 31 (7.0 days), ChAc activity increased approximately 5.4-fold and from stage 38+ (12.5 days) to stage 44, (18 days) ChAc activity increased approximately 3.6-fold with the major increase occurring during the 48-hour period from stage 42 to stage 44. The ontogenetic patterns for both enzymes are discussed in relation to morphological and functional differentiation. It is suggested that ChAc activity is a more reliable index of functional differentiation than is AChE and that the initial increase in AChE activity may be associated with some function other than synaptic transmission.