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Sample records for 3h site symmetry

  1. A systematic analysis of the spectra of trivalent actinide chlorides in D sub 3h site symmetry

    SciTech Connect

    Carnall, W.T.

    1989-11-01

    The optical spectra of actinide ions in the compound AnCl{sub 3} and doped into single crystal LaCl{sub 3} were interpreted in terms of transitions within 5f{sup N} configurations. Energy-level calculations were carried out using an effective operator Hamiltonian, the parameters of which were determined by fitting experimental data. Atomic and crystal-field matrices were diagonalized simultaneously assuming an approximate D{sub 3h} site symmetry. The spectroscopic data were taken from the literature but in most cases supplemented by unpublished measurements in absorption and in fluorescence. Spectroscopic data for each ion were analyzed independently, then the model parameters were intercompared and in many cases adjusted such that in the final fitting process the principal interactions showed uniform trends in parameter values with increasing atomic number. Consistent with analyses of the spectra of lanthanide ions in both LaCl{sub 3} and LaF{sub 3}, abrupt changes in magnitude of certain crystal-field parameters were found near the center of the 5f{sup N}-series. This resulted in two groups of parameter values, but with consistent trends for both halves of the series, and generally very good agreement between observed and computed energies. A new energy level chart based on computed crystal-field level energies for each trivalent actinide ion has been prepared. in addition, the parameters of the atomic part of each 5f{sup N} Hamiltonian were used to calculate the matrix elements of U{sup ({lambda})} for selected transitions. The values were tabulated to facilitate calculation of intensity-related parameters for 5f{sup N}-transitions using the Judd-Ofelt theory. 44 refs., 10 figs., 3 tabs.

  2. A systematic analysis of the spectra of trivalent actinide chlorides in D sub 3 h site symmetry

    SciTech Connect

    Carnall, W.T. )

    1992-06-15

    The optical spectra of actinide ions in the compound AnCl{sub 3} and doped into single-crystal LaCl{sub 3} were interpreted in terms of transitions within 5{ital f}{sup {ital N}} configurations. Energy-level calculations were carried out using an effective-operator Hamiltonian, the parameters of which were determined by fitting experimental data. Atomic and crystal-field matrices were diagonalized simultaneously assuming an approximate {ital D}{sub 3{ital h}} site symmetry. Spectroscopic data were taken from the literature but in most cases supplemented by unpublished measurements in absorption and in fluorescence. Data for each ion were analyzed independently, then the model parameters were intercompared and in many cases adjusted such that in the final fitting process the principal interactions showed uniform trends in parameter values with increasing atomic number. Consistent with analyses of the spectra of lanthanide ions in both LaCl{sub 3} and LaF{sub 3}, abrupt changes in magnitude of certain crystal-field parameters were found near the center of the 5{ital f}{sup {ital N}} series. This resulted in two groups of parameter values, but with consistent trends for both halves of the series, and generally very good agreement between observed and computed energies. A new energy-level chart based on computed crystal-field level energies for each trivalent actinide ion has been prepared.

  3. Parkinson's disease: decreased density of /sup 3/H-imipramine and /sup 3/H-paroxetine binding sites in putamen

    SciTech Connect

    Raisman, R.; Cash, R.; Agid, Y.

    1986-04-01

    The density of high-affinity /sup 3/H-imipramine and /sup 3/H-paroxetine binding sites (two serotonin-uptake blockers) was decreased in the putamen of parkinsonian patients. The correlation between serotonin levels and the number of /sup 3/H-imipramine and /sup 3/H-paroxetine binding sites suggests that they are located on serotoninergic nerve terminals and could be used to study serotoninergic innervation in the human brain. Since imipramine and paroxetine are powerful antidepressants, these results furthermore suggest that decreased serotoninergic transmission may be implicated in the pathophysiology of depression in Parkinson's disease.

  4. Partial chemical characterization of cyclopyrrolones ((/sup 3/H) suriclone) and benzodiazepines ((/sup 3/H)flunitrazepam) binding site: Differences

    SciTech Connect

    Zundel, J.L.; Blanchard, J.C.; Julou, L.

    1985-06-10

    Rat hippocampus membranes were treated with several protein modifying reagents (iodoacetamide, N-ethylmaleimide, tetranitromethane and N-acetylimidazole). The effects of these treatments on the binding sites of cyclopyrrolones ((/sup 3/H) suriclone), a new chemical family of minor tranquilizers, and benzodiazepines ((/sup 3/H) flunitrazepam) were investigated. Here the authors show that both ligands are similarly sensitive to cysteine alkylation: (/sup 3/H) suriclone and (/sup 3/H) flunitrazepam binding are reduced by iodoacetamide and slightly increased by N-ethylmaleimide. On the contrary they are clearly differentiated by tyrosine modification: (/sup 3/H) suriclone binding is not changed whereas (/sup 3/H) flunitrazepam binding is increased by tetranitromethane and decreased by N-acetylimidazole. The present findings and published evidence suggest cyclopyrrolones and benzodiazepines bind to distinct sites or to different allosteric forms of the benzodiazepine receptor. 28 references, 6 figures.

  5. Selective labeling of serotonin uptake sites in rat brain by (/sup 3/H)citalopram contrasted to labeling of multiple sites by (/sup 3/H)imipramine

    SciTech Connect

    D'Amato, R.J.; Largent, B.L.; Snowman, A.M.; Snyder, S.H.

    1987-07-01

    Citalopram is a potent and selective inhibitor of neuronal serotonin uptake. In rat brain membranes (/sup 3/H)citalopram demonstrates saturable and reversible binding with a KD of 0.8 nM and a maximal number of binding sites (Bmax) of 570 fmol/mg of protein. The drug specificity for (/sup 3/H)citalopram binding and synaptosomal serotonin uptake are closely correlated. Inhibition of (/sup 3/H)citalopram binding by both serotonin and imipramine is consistent with a competitive interaction in both equilibrium and kinetic analyses. The autoradiographic pattern of (/sup 3/H)citalopram binding sites closely resembles the distribution of serotonin. By contrast, detailed equilibrium-saturation analysis of (/sup 3/H)imipramine binding reveals two binding components, i.e., high affinity (KD = 9 nM, Bmax = 420 fmol/mg of protein) and low affinity (KD = 553 nM, Bmax = 8560 fmol/mg of protein) sites. Specific (/sup 3/H)imipramine binding, defined as the binding inhibited by 100 microM desipramine, is displaced only partially by serotonin. Various studies reveal that the serotonin-sensitive portion of binding corresponds to the high affinity sites of (/sup 3/H)imipramine binding whereas the serotonin-insensitive binding corresponds to the low affinity sites. Lesioning of serotonin neurons with p-chloroamphetamine causes a large decrease in (/sup 3/H)citalopram and serotonin-sensitive (/sup 3/H)imipramine binding with only a small effect on serotonin-insensitive (/sup 3/H)imipramine binding. The dissociation rate of (/sup 3/H)imipramine or (/sup 3/H)citalopram is not altered by citalopram, imipramine or serotonin up to concentrations of 10 microM. The regional distribution of serotonin sensitive (/sup 3/H)imipramine high affinity binding sites closely resembles that of (/sup 3/H)citalopram binding.

  6. Binding of [3H]idazoxan and of its methoxy derivative [3H] RX821002 in human fat cells: [3H]idazoxan but not [3H] RX821002 labels additional non-alpha 2-adrenergic binding sites.

    PubMed

    Langin, D; Paris, H; Lafontan, M

    1990-06-01

    Binding studies were carried out in human fat cell membranes with two alpha 2-adrenergic antagonists, [3H]idazoxan and its methoxy derivative [3H]RX821002. Inhibition studies with epinephrine enantiomers indicate that [3H]RX821002 only binds to alpha 2-adrenoceptors, whereas [3H]idazoxan labels alpha 2-adrenoceptors and additional nonadrenergic sites (NAIBS). NAIBS and alpha 2-adrenoceptors display different affinities towards drugs from various chemical families. Imidazoline and some guanidine derivatives exhibit a high affinity for NAIBS. Pharmacological studies of human NAIBS indicate that they are slightly different from those previously reported in the rabbit, suggesting the existence of several subtypes of NAIBS. Furthermore, NAIBS are different from the previously described "imidazoline-preferring sites." [3H]idazoxan and [3H]RX821002 saturation analyses were performed in human adipocytes from different anatomical locations, in order to compare the number of NAIBS and alpha 2-adrenoceptors. Although there was an important variation in NAIBS and alpha 2-adrenoceptor numbers in the studied samples, a very poor correlation was obtained between the Bmax values of the two sites. Moreover, alkylation of alpha 2-adrenoceptors by phenoxybenzamine produces a 90% reduction in accessible [3H]RX821002 binding sites, without modification of [3H]idazoxan binding. These data show that NAIBS are not closely related to the alpha 2-adrenergic molecule. In addition, benextramine appears to be a reversible competitor at NAIBS. [3H]idazoxan binding, but not [3H]RX821002 binding, is sensitive to K+, suggesting that the domains involved in the ligand-NAIBS interaction are different from those involved in the ligand-alpha 2-adrenoceptor interaction.

  7. Different effects of serotonin antagonists on /sup 3/H-mianserin and /sup 3/H-ketanserin recognition sites

    SciTech Connect

    Gandolfi, O.; Barbaccia, M.L.; Costa, E.

    1985-02-25

    In minces prepared from the frontal cortex of rats treated with ketanserin (10 mg/kg i.p.) or mianserin (5 mg/kg i.p.) twice daily for 21 days, the Vmax of the adenylate cyclase stimulated by NE (100 ..mu..M) is attenuated, suggesting that ketanserin and mianserin share with a number of antidepressants the ability to attenuate the adenylate cyclase stimulation by NE. Ketanserin, given with the above mentioned dose schedule for 7 consecutive days, reduced the Bmax of 5HT/sub 2/ recognition sites but failed to change either the Bmax or the apparent Kd of /sup 3/H-mianserin binding. A significant decrease in the Bmax of 5HT/sub 2/ binding sites is elicited also by a single injection of mianserin. This drug also down-regulates its own binding when given twice daily for 3 weeks. From this and other information, it is concluded that ketanserin and mianserin bind to distinct recognition sites. The possibility that 5HT/sub 2/ and mianserin recognition sites are functionally related and that serotonergic synapses are modulated by multiple chemical signals might be considered. 34 references, 3 figures.

  8. Comparison of dopamine receptor sites labeled by (/sup 3/H)-S-sulpiride and (/sup 3/H)-spiperone in striatum

    SciTech Connect

    Zahniser, N.R.; Dubocovich, M.L.

    1983-12-01

    Binding of the radiolabeled active isomer of the neuroleptic sulpiride, (/sup 3/H)-S-sulpiride, to rat and rabbit striatal membranes was characterized. Regardless of whether the specific binding of (/sup 3/H)-S-sulpiride was defined with spiperone or the active isomers of butaclamol or flupenthixol, a single homogeneous++ population of binding sites (rat: Kd . 5.6 nM, maximum binding . 590 fmol/mg of protein; rabbit: Kd . 8.3 nM, maximum binding . 540 fmol/mg of protein) was detected. The pharmacological profile of these sites was characteristic of that described for the dopaminergic D-2 receptor subtype. To determine whether (/sup 3/H)-S-sulpiride and (/sup 3/H)spiperone label common sites in the striatum, the binding of these two radioligands was compared under similar assay conditions. When specific binding of (/sup 3/H)spiperone was defined with S-sulpiride, (/sup 3/H)spiperone labeled the same number of binding sites as (/sup 3/H)-S-sulpiride despite the fact that the affinity of the sites for (/sup 3/H)spiperone was 80- to 90-fold higher than for (/sup 3/H)-S-sulpiride. When specific binding of (/sup 3/H)spiperone was defined with either (+)-butaclamol or (alpha)-flupenthixol, however, approximately 30% more sites were labeled. The predominant site labeled by (/sup 3/H)spiperone also possessed the characteristics of the D-2 receptor. It is concluded that (/sup 3/H)-S-sulpiride under the conditions used is a selective radioligand with which dopamine receptors of the D-2 subtype can be directly measured and localized. (/sup 3/H)Spiperone can be used to detect the same sites only if specific binding is defined with S-sulpiride.

  9. Separate [3H]-nitrendipine binding sites in mitochondria and plasma membranes of bovine adrenal medulla.

    PubMed Central

    Ballesta, J. J.; Garcia, A. G.; Gutierrez, L. M.; Hidalgo, M. J.; Palmero, M.; Reig, J. A.; Viniegra, S.

    1990-01-01

    1. Two binding sites for the 1,4-dihydropyridine (DHP) derivative [3H]-nitrendipine have been found in the bovine adrenal medulla. The high-affinity site (Kd = 0.48 nM and Bmax = 128 fmol mg-1 protein) was specifically located in purified plasma membranes. The low-affinity site (Kd = 252 nM and Bmax = 169 pmol mg-1 protein) was located only in mitochondria. Chromaffin granule membranes lacked specific binding sites for [3H]-nitrendipine. 2. Kinetic analysis of the rates of association and dissociation of [3H]-nitrendipine, saturation isotherms and displacement experiments with unlabelled nitrendipine and PN200-110 revealed single, homogeneous populations of high- and low-affinity sites in plasma and mitochondrial membranes, respectively. 3. The high affinity site was sensitive to Ca2+ deprivation and heating; it was practically unaffected by changes in ionic strength of the medium and its optimal pH was slightly alkaline. This site exhibited a strong DHP stereoselectivity; diltiazem increased and verapamil decreased the affinity of [3H]-nitrendipine. 4. In contrast, binding of [3H]-nitrendipine to the low affinity site was more heat resistant and less affected by Ca2+ removal. Its optimal pH was slightly acid and the increase in ionic strength enhanced the number of available sites. The site had no DHP stereoselectivity. Verapamil decreased the dissociation constant of [3H]-nitrendipine acting in a non-competitive manner; diltiazem did not affect equilibrium binding parameters of [3H]-nitrendipine. 5. These results suggest that both biding sites reflect different receptor entities. The high-affinity binding site corresponds to the dihydropyridine receptor associated with the L-type calcium channel. The function of the mitochondrial, low-affinity binding site is, at present, unknown. PMID:1704272

  10. Autoradiographic localization of /sup 3/H-paroxetine-labeled serotonin uptake sites in rat brain

    SciTech Connect

    De Souza, E.B.; Kuyatt, B.L.

    1987-01-01

    Paroxetine is a potent and selective inhibitor of serotonin uptake into neurons. Serotonin uptake sites have been identified, localized, and quantified in rat brain by autoradiography with 3H-paroxetine; 3H-paroxetine binding in slide-mounted sections of rat forebrain was of high affinity (KD = 10 pM) and the inhibition affinity constant (Ki) values of various drugs in competing 3H-paroxetine binding significantly correlated with their reported potencies in inhibiting synaptosomal serotonin uptake. Serotonin uptake sites labeled by 3H-paroxetine were highly concentrated in the dorsal and median raphe nuclei, central gray, superficial layer of the superior colliculus, lateral septal nucleus, paraventricular nucleus of the thalamus, and the islands of Calleja. High concentrations of 3H-paroxetine binding sites were found in brainstem areas containing dopamine (substantia nigra and ventral tegmental area) and norepinephrine (locus coeruleus) cell bodies. Moderate concentrations of 3H-paroxetine binding sites were present in laminae I and IV of the frontal parietal cortex, primary olfactory cortex, olfactory tubercle, regions of the basal ganglia, septum, amygdala, thalamus, hypothalamus, hippocampus, and some brainstem areas including the interpeduncular, trigeminal, and parabrachial nuclei. Lower densities of 3H-paroxetine binding sites were found in other regions of the neocortex and very low to nonsignificant levels of binding were present in white matter tracts and in the cerebellum. Lesioning of serotonin neurons with 3,4-methylenedioxyamphetamine caused large decreases in 3H-paroxetine binding. The autoradiographic distribution of 3H-paroxetine binding sites in rat brain corresponds extremely well to the distribution of serotonin terminals and cell bodies as well as with the pharmacological sites of action of serotonin.

  11. Quantitative autoradiography of /sup 3/H-nomifensine binding sites in rat brain

    SciTech Connect

    Scatton, B.; Dubois, A.; Dubocovich, M.L.; Zahniser, N.R.; Fage, D.

    1985-03-04

    The distribution of /sup 3/H-nomifensine binding sites in the rat brain has been studied by quantitative autoradiography. The binding of /sup 3/H-nomifensine to caudate putamen sections was saturable, specific, of a highly affinity (Kd = 56 nM) and sodium-dependent. The dopamine uptake inhibitors benztropine, nomifensine, cocaine, bupropion and amfonelic acid were the most potent competitors of /sup 3/H-nomifensine binding to striatal sections. The highest levels of (benztropine-displaceable) /sup 3/H-nomifensine binding sites were found in the caudate-putamen, the olfactory tubercle and the nucleus accumbens. 6-Hydroxy-dopamine-induced lesion of the ascending dopaminergic bundle resulted in a marked decrease in the /sup 3/H-ligand binding in these areas. Moderately high concentrations of the /sup 3/H-ligand were observed in the bed nucleus of the stria terminalis, the anteroventral thalamic nucleus, the cingulate cortex, the lateral septum, the hippocampus, the amygdala, the zona incerta and some hypothalamic nuclei. There were low levels of binding sites in the habenula, the dorsolateral geniculate body, the substantia nigra, the ventral tegmental area and the periaqueductal gray matter. These autoradiographic data are consistent with the hypothesis that /sup 3/H-nomifensine binds primarily to the presynaptic uptake site for dopamine but also labels the norepinephrine uptake site. 33 references, 2 figures, 1 table.

  12. Binding of [3H]SCH23390 to a non-dopaminergic site in bovine kidney.

    PubMed

    Hollis, C M; Turner, J D; Strange, P G

    1992-05-08

    Binding of the D1 dopamine receptor antagonist [3H]SCH23390 to bovine renal cortical membranes has been studied. Specific binding of [3H]SCH23390 was saturable and reversible and stereoisomers of SCH23390 competed stereoselectively. In contrast, competition with the isomers of butaclamol was not stereoselective and dopamine failed to compete for the [3H]SCH23390 binding site. The site is therefore not a D1 dopamine receptor. Competition studies with a very wide range of compounds failed to define the nature of the [3H]SCH23390 binding sites in renal cortex whereas in parallel studies the characteristics of [3H]SCH23390 binding in caudate nucleus were entirely consistent with those of D1 dopamine receptors. The nature of [3H]SCH23390 binding in preparations of tubular and glomerular membranes was found to be virtually identical to those of crude renal cortical membranes indicating lack of compartmentation of these sites. Autoradiographic studies of [3H]SCH23390 binding in bovine kidney showed significantly higher levels of binding sites in renal cortex compared with renal medulla and this was confirmed by direct ligand binding studies.

  13. Human retina contains polyamine sensitive [3H]-ifenprodil binding sites: implications for neuroprotection?

    PubMed Central

    Sharif, N; Xu, S

    1999-01-01

    AIMS—This study characterised the pharmacology of [3H]-ifenprodil binding to the polyamine binding sites (PBS) on the N-methyl-D-aspartate (NMDA) receptor channel complex on human retinas. These data were correlated with the known neuroprotective effects of ifenprodil and eliprodil.
METHODS—Specific binding of [3H]-ifenprodil (under sigma site blockade) was investigated using human retinal homogenates and radioligand binding techniques. Scatchard and competition analyses were utilised to define the pharmacology of the [3H]-ifenprodil binding sites.
RESULTS—Specific binding of [3H]-ifenprodil comprised 73% (SEM 3%) of total and reflected interaction with two affinity sites (Kds = 0.39 and 4.3 µM) of different densities (Bmax = 14.4 and 105 pmol/ mg protein) (n = 5). The rank order of affinity of compounds competing for [3H]-ifenprodil binding to the high affinity PBS was: ifenprodil > eliprodil > arcaine > spermine > diaminodecane > spermidine > putrescine >> MK-801 (n = 3-7). However, [3H]-ifenprodil binding was minimally inhibited by glutamate, NMDA, and kainate.
CONCLUSION—These studies have shown, for the first time, the presence of specific [3H]-ifenprodil binding sites in the human retina with pharmacological characteristics of PBS associated with the NMDA receptor ionophore complex. The neuroprotective effects of eliprodil and ifenprodil may, in part, be mediated via these [3H]-ifenprodil labelled sites.

 Keywords: retina; neuroprotection; eliprodil; NMDA receptors PMID:10396205

  14. Autoradiographic localization of [3H]thiocolchicoside binding sites in the rat brain and spinal cord.

    PubMed

    Balduini, W; De Angelis, V; Mazzoni, E; Depoortere, H; Cattabeni, F; Cimino, M

    2001-06-01

    Thiocolchicoside is used in humans as a myorelaxant drug with anti-inflammatory and analgesic activity. Recently we established the experimental conditions that allowed the identification of [3H]thiocolchicoside binding sites in synaptic membranes of rat spinal cord and cerebral cortex. The pharmacological characterization of these sites indicated that GABA and several of its agonists and antagonists, as well as strychnine, were able to interact with [3H]thiocolchicoside binding in a dose-dependent manner and with different affinities. In order to gain more insight into the nature and the anatomical distribution of the binding sites labeled by [3H]thiocolchicoside, in the present study we examined the localization of these sites on parasagittal and coronal sections of the rat brain and spinal cord, respectively, using receptor autoradiography. In the spinal cord an intense signal was observed in the gray matter, with the highest density occurring in the superficial layers of the dorsal horns. Strychnine completely displaced [3H]thiocolchicoside binding, whereas GABA only partially removed the radioligand from its binding sites. In the brain, specific binding occurred in several areas and was displaced by both GABA and strychnine. The distribution of [3H]thiocolchicoside binding sites in brain sections, however, did not match that found for [3H]muscimol. Furthermore, cold thiocolchicoside was not able to completely displace [3H]muscimol binding, and showed a different efficacy in the various areas labeled by the radioligand. We conclude that thiocolchicoside may interact with a subpopulation of GABA(A) receptors having low-affinity binding sites for GABA. Furthermore, the observed sensitivity to strychnine in the spinal cord indicates an interaction also with strychnine-sensitive glycine receptors, suggesting that the pharmacological effects of thiocolchicoside may be the result of its interaction with different receptor populations.

  15. Calcium channel receptor sites for (+)-[3H]PN 200-110 in coronary artery.

    PubMed

    Yamada, S; Kimura, R; Harada, Y; Nakayama, K

    1990-01-01

    The receptor sites for 1,4-dihydropyridine (DHP) Ca++ channel antagonists in porcine coronary artery were identified and characterized by a binding assay using (+)-[3H]PN 200-110 as a radioligand. Specific (+)-[3H]PN 200-110 binding in porcine coronary artery was saturable, reversible and of high affinity (Kd = 0.24 nM) and it showed a pharmacological specificity as well as stereoselectivity which characterized the receptor sites for DHP Ca++ channel antagonists. DHP antagonists competed for the (+)-[3H]PN 200-110 binding in order: PN 200-110 greater than mepirodipine greater than nisoldipine greater than nicardipine greater than nitrendipine greater than nimodipine greater than nifedipine greater than (-)-PN 200-110. (+)-PN 200-110 was approximately 140 times as potent as the (-)-isomer. The potencies (PKi) of these eight DHP Ca++ channel antagonists in competing for (+)-[3H]PN 200-110 binding sites in porcine coronary artery correlated well with their pharmacological potencies. Specific (+)-[3H]PN 200-110 binding in the coronary artery was enhanced by d-cis-diltiazem and was inhibited incompletely by verapamil and D-600. In EDTA-pretreated coronary artery, the maximal number of binding sites for specific (+)-[3H]PN 200-110 binding was reduced (80%) markedly, and it was restored to the untreated level by the addition of Ca++ and Mg++.(ABSTRACT TRUNCATED AT 250 WORDS)

  16. Tests of Predictions of the Algebraic Cluster Model: the Triangular D 3h Symmetry of 12C

    NASA Astrophysics Data System (ADS)

    Gai, Moshe

    2016-07-01

    A new theoretical approach to clustering in the frame of the Algebraic Cluster Model (ACM) has been developed. It predicts rotation-vibration structure with rotational band of an oblate equilateral triangular symmetric spinning top with a D 3h symmetry characterized by the sequence of states: 0+, 2+, 3-, 4±, 5- with a degenerate 4+ and 4- (parity doublet) states. Our measured new 2+ 2 in 12C allows the first study of rotation-vibration structure in 12C. The newly measured 5- state and 4- states fit very well the predicted ground state rotational band structure with the predicted sequence of states: 0+, 2+, 3-, 4±, 5- with almost degenerate 4+ and 4- (parity doublet) states. Such a D 3h symmetry is characteristic of triatomic molecules, but it is observed in the ground state rotational band of 12C for the first time in a nucleus. We discuss predictions of the ACM of other rotation-vibration bands in 12 C such as the (0+) Hoyle band and the (1-) bending mode with prediction of (“missing 3- and 4-”) states that may shed new light on clustering in 12C and light nuclei. In particular, the observation (or non observation) of the predicted (“missing”) states in the Hoyle band will allow us to conclude the geometrical arrangement of the three alpha particles composing the Hoyle state at 7.6542 MeV in 12C. We discuss proposed research programs at the Darmstadt S-DALINAC and at the newly constructed ELI-NP facility near Bucharest to test the predictions of the ACM in isotopes of carbon.

  17. Characterization of antralin: an endogenous protein inhibitor of radioligand binding to (/sup 3/H)RO 5-4864 and (/sup 3/H)nitrendipine binding sites

    SciTech Connect

    Mantione, C.R.; Goldman, M.E.; Bolger, G.T.; Lueddens, H.W.M.; Paul, S.M.; Skolnick, P.

    1986-03-01

    The presence of substances isolated from rat antral stomach that inhibit the binding of (/sup 3/H)Ro 5-4864 (4'-chlorodiazepam) to peripheral-type benzodiazepine receptors (PBR), but do not affect the binding of (/sup 3/H)diazepam to brain-type benzodiazepine receptors have been described. These substances, now obtained by isolation on Sep-Pak C/sub 18/ cartridges, also had no effect on (/sup 3/)PK 11195 binding which labels an antagonist site associated with PBR. Neither was any significant inhibition of (/sup 3/H)Ro 15-1788, (/sup 3/H)..beta..CCM, or (/sup 3/H)dihydroalprenolol binding observed. However, the Sep-Pak eluates were found to produce a concentration-dependent inhibition of (/sup 3/H)nitrendipine binding equivalent to that seen with (/sup 3/H)Ro 5-4864. This material, termed antralin, reduced the apparent K/sub d/ of both radioligands without significantly affecting B/sub max/. Its activity was destroyed by both heat treatment and pronase, and partially reduced by trypsin. Furthermore, its activity was enhanced by Ca/sup + +/ (0.1 mM). Antralin levels were unevenly distributed in rat tissues. These findings suggest that antralin is a protein that may regulate both PBR and dihydropyridine Ca/sup + +/-channel antagonist binding sites in vivo.

  18. Characterization of [3H]thiocolchicoside binding sites in rat spinal cord and cerebral cortex.

    PubMed

    Balduini, W; Cimino, M; Depoortere, H; Cattabeni, F

    1999-07-02

    Thiocolchicoside, a semi-synthetic derivative of the naturally occurring compound colchicoside with a relaxant effect on skeletal muscle, has been found to displace both [3H]gamma-aminobutyric acid ([3H]GABA) and [3H]strychnine binding, suggesting an interaction with both GABA and strychnine-sensitive glycine receptors. In order to gain further insight into the interaction of thiocolchicoside with these receptors, the binding of [3H]thiocolchicoside in rat spinal cord-brainstem and cortical synaptic membranes was characterized. [3H]Thiocolchicoside binding was saturable in both tissues examined. In spinal cord-brainstem membranes, we found a K(D) of 254 +/- 47 nM and a Bmax of 2.39 +/- 0.36 pmol/mg protein, whereas in cortical membranes, a K(D) of 176 nM and a Bmax of 4.20 pmol/mg protein was observed. A similar K(D) value was found in kinetic experiments performed in spinal cord-brainstem membranes. Heterologous displacement experiments showed that GABA and strychnine displaced the binding in a dose-dependent manner, whereas glycine was ineffective. [3H]Thiocolchicoside binding was also displaced by several GABA(A) receptor agonists and antagonists, but not by baclofen, flunitrazepam, guvacine, picrotoxin or by other drugs unrelated to GABA transmission. In spinal cord-brainstem, and to a lower extent, in cortical membranes, GABA and its analogs were not able to completely displace [3H]thiocolchicoside specific binding indicating that, besides GABA(A) receptors, thiocolchicoside can bind to another unidentified site. Unlabelled thiocolchicoside, however, completely displaced [3H]muscimol binding both in cortical and in spinal cord-brainstem synaptic membranes with an IC50 in the low microM range. Neurosteroids were found to modulate the binding in cortical but not in spinal cord-brainstem synaptic membranes. We conclude that [3H]thiocolchicoside binding shows a pharmacological profile indicating an interaction with the GABA(A) receptor. The different affinities

  19. Interaction of thiocolchicoside with [3H]strychnine binding sites in rat spinal cord and brainstem.

    PubMed

    Cimino, M; Marini, P; Cattabeni, F

    1996-12-27

    Radioreceptor binding assays and receptor autoradiography were used to investigate the activity of thiocolchicoside on strychnine-sensitive binding sites in rat brain and spinal cord using [3H]strychnine as a ligand. Thiocolchicoside displaced the binding of [3H]strychnine with an affinity similar to that of unlabeled glycine, and showed a Hill coefficient and proportionality parameter (P) less than unity. The activity of thiocolchicoside toward [3H]strychnine binding sites was confirmed in autoradiographic studies. The results suggest that thiocolchicoside behaves as an allosteric compound acting on the strychnine-sensitive glycine receptor in rat brainstem and spinal cord, and that this may provide a possible mechanism for the myorelaxant activity of this colchicoside derivative, the first clinically useful drug acting on this receptor.

  20. Characteristics of central binding sites for ( sup 3 H) DAMGO in spontaneously hypertensive rats

    SciTech Connect

    Gulati, A.; Bhargava, H.N. )

    1990-01-01

    The binding of ({sup 3}H) DAMGO, a highly selective ligand for {mu}-opiate receptors, to membranes of discrete brain regions and spinal cord of 10 week old spontaneously hypertensive (SHR) and normotensive Wistar-Kyoto (WKY) rats were determined. The brain regions examined were hypothalamus, amygdala, hippocampus, corpus striatum, pons and medulla, midbrain and cortex. ({sup 3}H) DAMGO bound to membranes of brain regions and spinal cord at a single high affinity site. The receptor density (B{sub max} value) and apparent dissociation constant (K{sub d} value) of ({sup 3}H) DAMGO to bind to membranes of hippocampus, corpus striatum, pons and medulla, cortex and spinal cord of WKY and SHR rats did not differ. The B{sub max} value of ({sup 3}H) DAMGO in membranes of hypothalamus and midbrain of SHR rats was significantly higher than in WKY rats but the K{sub d} values in the two strains did not differ. On the other hand, the B{sub max} value of ({sup 3}H) DAMGO in membranes of amygdala of SHR rats was lower than that of WKY rats but the K{sub d} values in the two strains were similar.

  1. Distribution of 3H-GABA uptake sites in the nematode Ascaris

    SciTech Connect

    Guastella, J.; Stretton, A.O. )

    1991-05-22

    The distribution of uptake sites for the inhibitory neurotransmitter gamma-aminobutyric acid (GABA) in the nematode Ascaris suum was examined by autoradiography of 3H-GABA uptake. Single neural processes in both the ventral and dorsal nerve cords were labeled with 3H-GABA. Serial section analysis identified the cells of origin of these processes as the RMEV-like and RMED-like neurons. These cells belong to a set of four neurons in the nerve ring, all of which are labeled by 3H-GABA. 3H-GABA labeling of at least two other sets of cephalic neurons was seen. One of these pairs consists of medium-sized lateral ganglia neurons, located at the level of the amphid commissure bundle. A second pair is located in the lateral ganglia at the level of the deirid commissure bundle. The position and size of these lateral ganglia cells suggest that they are the GABA-immunoreactive lateral ganglia cells frequently seen in whole-mount immunocytochemical preparations. Four neuronal cell bodies located in the retrovesicular ganglion were also labeled with 3H-GABA. These cells, which are probably cholinergic excitatory motor neurons, do not contain detectable GABA-like immunoreactivity. Heavy labeling of muscle cells was also observed. The ventral and dorsal nerve cord inhibitory motor neurons, which are known to contain GABA-like immunoreactivity, were not labeled above background with 3H-GABA. Together with the experiments reported previously, these results define three classes of GABA-associated neurons in Ascaris: (1) neurons that contain endogenous GABA and possess a GABA uptake system; (2) neurons that contain endogenous GABA, but that either lack a GABA uptake system or possess a GABA uptake system of low activity; (3) neurons that possess a GABA uptake system, but that lack endogenous GABA.

  2. Characterization of binding sites for /sup 3/H-spiroperidol in human retina

    SciTech Connect

    McGonigle, P.; Wax, M.B.; Molinoff, P.B.

    1988-05-01

    Binding sites for the D-2-selective antagonist (/sup 3/H)-spiroperidol were characterized in human retina. Nonspecific binding, measured in the presence of 2 microM (+)-butaclamol, made up 20% of total binding. Scatchard analysis of the binding of (/sup 3/H)-spiroperidol resulted in linear plots and yielded a Kd value of 87 pM and a Bmax value of 1500 fmol/mg protein. In studies of the inhibition of the binding of (/sup 3/H)-spiroperidol, (+)-butaclamol was approximately 1000-fold more potent than the (-)-stereoisomer. The inhibition curve for dopamine was shifted to the right and the Hill coefficient was increased by the addition of 300 microM GTP. This effect was agonist-specific and suggests that some of the receptors are coupled to stimulation or inhibition of the enzyme adenylate cyclase. The inhibition curves for most of the antagonists had Hill coefficients between 0.6 and 0.8. Hill coefficients were also consistently less than 1.0 for agonists even in the presence of GTP. Nonlinear regression analysis of untransformed data revealed that these shallow inhibition curves were best explained by the presence of two populations of binding sites, 40% of the sites having a high affinity for dopamine in the presence of GTP and domperidone and the remaining 60% having a lower affinity for these ligands. The larger population of sites had a higher affinity for sulpiride, fluphenazine, and N-propylnorapomorphine in the presence of GTP. The possibility that either of these classes of sites consisted of serotonin receptors was ruled out by the finding that the 5-HT2 antagonist ketanserin had a low affinity for both classes of sites.

  3. Characterization of binding sites for 3H-spiroperidol in human retina.

    PubMed

    McGonigle, P; Wax, M B; Molinoff, P B

    1988-05-01

    Binding sites for the D-2-selective antagonist (3H)-spiroperidol were characterized in human retina. Nonspecific binding, measured in the presence of 2 microM (+)-butaclamol, made up 20% of total binding. Scatchard analysis of the binding of (3H)-spiroperidol resulted in linear plots and yielded a Kd value of 87 pM and a Bmax value of 1500 fmol/mg protein. In studies of the inhibition of the binding of (3H)-spiroperidol, (+)-butaclamol was approximately 1000-fold more potent than the (-)-stereoisomer. The inhibition curve for dopamine was shifted to the right and the Hill coefficient was increased by the addition of 300 microM GTP. This effect was agonist-specific and suggests that some of the receptors are coupled to stimulation or inhibition of the enzyme adenylate cyclase. The inhibition curves for most of the antagonists had Hill coefficients between 0.6 and 0.8. Hill coefficients were also consistently less than 1.0 for agonists even in the presence of GTP. Nonlinear regression analysis of untransformed data revealed that these shallow inhibition curves were best explained by the presence of two populations of binding sites, 40% of the sites having a high affinity for dopamine in the presence of GTP and domperidone and the remaining 60% having a lower affinity for these ligands. The larger population of sites had a higher affinity for sulpiride, fluphenazine, and N-propylnorapomorphine in the presence of GTP. The possibility that either of these classes of sites consisted of serotonin receptors was ruled out by the finding that the 5-HT2 antagonist ketanserin had a low affinity for both classes of sites.

  4. Stereoselective L-(3H)quinuclidinyl benzilate-binding sites in nervous tissue of Aplysia californica: evidence for muscarinic receptors

    SciTech Connect

    Murray, T.F.; Mpitsos, G.J.; Siebenaller, J.F.; Barker, D.L.

    1985-12-01

    The muscarinic antagonist L-(/sup 3/H)quinuclidinyl benzilate (L-(/sup 3/H)QNB) binds with a high affinity (Kd = 0.77 nM) to a single population of specific sites (Bmax = 47 fmol/mg of protein) in nervous tissue of the gastropod mollusc, Aplysia. The specific L-(/sup 3/H)QNB binding is displaced stereoselectively by the enantiomers of benzetimide, dexetimide, and levetimide. The pharmacologically active enantiomer, dexetimide, is more potent than levetimide as an inhibitor of L-(/sup 3/H)QNB binding. Moreover, the muscarinic cholinergic ligands, scopolamine, atropine, oxotremorine, and pilocarpine are effective inhibitors of the specific L-(/sup 3/H)QNB binding, whereas nicotinic receptor antagonists, decamethonium and d-tubocurarine, are considerably less effective. These pharmacological characteristics of the L-(/sup 3/H)QNB-binding site provide evidence for classical muscarinic receptors in Aplysia nervous tissue. The physiological relevance of the dexetimide-displaceable L-(/sup 3/H)QNB-binding site was supported by the demonstration of the sensitivity of the specific binding to thermal denaturation. Specific binding of L-(/sup 3/H)QNB was also detected in nervous tissue of another marine gastropod, Pleurobranchaea californica. The characteristics of the Aplysia L-(/sup 3/H)QNB-binding site are in accordance with studies of numerous vertebrate and invertebrate tissues indicating that the muscarinic cholinergic receptor site has been highly conserved through evolution.

  5. Preferential affinity of /sup 3/H-2-oxo-quazepam for type I benzodiazepine recognition sites in the human brain

    SciTech Connect

    Corda, M.G.; Giorgi, O.; Longoni, B.; Ongini, E.; Montaldo, S.; Biggio, G.

    1988-01-01

    The hypnotic drug quazepam and its active metabolite 2-oxo-quazepam (2-oxo-quaz) are two benzodiazepines (BZ) containing a trifluoroethyl moiety on the ring nitrogen at position 1, characterized by their preferential affinity for Type I BZ recognition sites. In the present study we characterized the binding of /sup 3/H-2-oxo-quaz in discrete areas of the human brain. Saturation analysis demonstrated specific and saturable binding of /sup 3/H-2-oxo-quaz to membrane preparations from human cerebellum. Hill plot analysis of displacement curves of /sup 3/H-flunitrazepam binding by 2-oxo-quaz yielded Hill coefficients of approximately 1 in the cerebellum and significantly less than 1 in the cerebral cortex, hippocampus, caudate nucleus, thalamus and pons. Self and cross displacement curves for /sup 3/H-FNT and /sup 3/H-2-oxo-quaz binding in these brain areas indicated that 2-oxo-quaz binds with different affinities to two populations of binding sites. High affinity binding sites were more abundant in the cerebellum, cerebral cortex, hippocampus and thalamus, whereas low affinity sites were predominant in the caudate nucleus and pons. Competition studies of /sup 3/H-2-oxo-quaz and /sup 3/H-FNT using unlabelled ligands indicated that compounds which preferentially bind to Type I sites are more potent at displacing /sup 3/H-2-oxo-quaz than /sup 3/H-FNT from cerebral cortex membrane preparations. 26 references, 2 figures, 3 tables.

  6. Multiple sup 3 H-oxytocin binding sites in rat myometrial plasma membranes

    SciTech Connect

    Crankshaw, D.; Gaspar, V.; Pliska, V. )

    1990-01-01

    The affinity spectrum method has been used to analyse binding isotherms for {sup 3}H-oxytocin to rat myometrial plasma membranes. Three populations of binding sites with dissociation constants (Kd) of 0.6-1.5 x 10(-9), 0.4-1.0 x 10(-7) and 7 x 10(-6) mol/l were identified and their existence verified by cluster analysis based on similarities between Kd, binding capacity and Hill coefficient. When experimental values were compared to theoretical curves constructed using the estimated binding parameters, good fits were obtained. Binding parameters obtained by this method were not influenced by the presence of GTP gamma S (guanosine-5'-O-3-thiotriphosphate) in the incubation medium. The binding parameters agree reasonably well with those found in uterine cells, they support the existence of a medium affinity site and may allow for an explanation of some of the discrepancies between binding and response in this system.

  7. (/sup 3/H)forskolin- and (/sup 3/H)dihydroalprenolol-binding sites and adenylate cyclase activity in heart of rats fed diets containing different oils

    SciTech Connect

    Alam, S.Q.; Ren, Y.F.; Alam, B.S.

    1988-03-01

    The characteristics of the cardiac adenylate cyclase system were studied in rats fed diets containing fish oil (menhaden oil) and other oils. Adenylate cyclase activity generally was higher in cardiac homogenates and membranes of rats fed diet containing 10% menhaden oil than in the other oils. The increase in enzyme activity, especially in forskolin-stimulated activity, was associated with an increase in the concentration of the (/sup 3/H) forskolin-binding sites in cardiac membranes of rats fed menhaden oil. The beta-adrenergic receptor concentration was not significantly altered although the affinity for (/sup 3/H)dihydroalprenolol-binding was lower in membranes of rats fed menhaden oil than those fed the other oils. omega-3 fatty acids from menhaden oil were incorporated into the cardiac membrane phospholipids. The results suggest that the observed increase in myocardial adenylate cyclase activity of rats fed menhaden oil may be due to an increase in the number of the catalytic subunits of the enzyme or due to a greater availability of the forskolin-binding sites.

  8. (/sup 3/H) spiperone binding sites in rat primary cultures, C6 glioma, and B104 neuroblastoma

    SciTech Connect

    Severson, J.A.; de Vellis, J.S.; Finch, C.E.

    1980-01-01

    Binding sites for (/sup 3/H) spiperone were detected on membranes from primary glial cultures from neonatal rat cortex and striatum and from the C6 glioma cells. (/sup 3/H) spiperone binding was displacable by d-butaclamol. However, competition studies suggest that (/sup 3/H) spiperone binding to primary glial cultures was mainly to serotonergic sites, and binding to the C6 glioma was alpha-adrenergic. No specific binding was detected to membranes from B104 neuroblastoma cells. Although (/sup 3/H) spiperone binding to glial sites in whole striatum under generally used conditions is small (about 10%), the striatal glial hyperactivity which is often associated with neuronal degeneration could lead to an overestimation of presumed neuronal binding sites for dopaminergic ligands.

  9. [[superscript 3]H]-Flunitrazepam-Labeled Benzodiazepine Binding Sites in the Hippocampal Formation in Autism: A Multiple Concentration Autoradiographic Study

    ERIC Educational Resources Information Center

    Guptill, Jeffrey T.; Booker, Anne B.; Gibbs, Terrell T.; Kemper, Thomas L.; Bauman, Margaret L.; Blatt, Gene J.

    2007-01-01

    Increasing evidence indicates that the GABAergic system in cerebellar and limbic structures is affected in autism. We extended our previous study that found reduced [[superscript 3]H] flunitrazepam-labeled benzodiazepine sites in the autistic hippocampus to determine whether this reduction was due to a decrease in binding site number (B [subscript…

  10. Characterization of imidazole binding sites labeled by /sup 3/H-p-aminoclonidine in the bovine ventrolateral medulla (VLM)

    SciTech Connect

    Ernsberger, P.R.; Mann, J.J.; Resi, D.J.

    1986-03-01

    Since vasodepressor responses to clonidine (CLON) are mediated by neurons in the C1 area of VLM, and CLON, an imidazole (IM), bind to IM as well as alpha-adrenergic receptors in brain, the authors characterized binding sites for CLON in RVL. IM sites were measured in preincubated, washed P/sub 2/ membranes (0.1 mg protein/ml) of YLM using /sup 3/H-p-aminoclonidine (/sup 3/H-PAC) as a radioligand (40 min., 25/sup 0/C). (-)-Norepinephrine (NE; 10 ..mu..M) inhibited only 70% of specific /sup 3/H-PAC binding (1.0 nM) as defined by 10 ..mu..M phentolamine. The sites displaced by NE resemble alpha/sub 2/-adrenergic receptors. When 10..mu..M NE was included in the incubation medium, the remaining /sup 3/H-PAC sites had a high affinity for CLON (IC/sub 50/ = 6 +/- 1 nM) and were saturable (K/sub D/ = 1.5 +/- 0.4 nM). Imidazole-4-acetic acid (IC/sub 50/ = 800 +/- 23 nM) and cimetadine (IC/sub 50/ = 480 +/- 88 nM) potently inhibited these non-adrenergic sites, but did not affect total /sup 3/H-PAC binding to cerebral cortical membranes indicating regional specificity. Histamine was a weak inhibitor (IC/sub 50/ = 38 +/- 3 ..mu..M) in cortex, but was more potent (IC/sub 50/ = 2 +/- 1 ..mu..M) in the RVL. The putative endogenous ligand clonidine displacing substance (CDS), has a 9-fold selectivity of the IM component of /sup 3/H-PAC binding in VLM. The authors conclude CLON binds to IM and adrenergic recognition sites in VLM. Binding to one or both sites may mediate the vasodepressor VLM. Binding to one or both sites may mediate the vasodepressor actions of the drug actions of the drug.

  11. Following macromolecular interactions and sugar metabolism using site specific /sup 3/H labelling and NMR spectroscopy

    SciTech Connect

    Williams, P.; Morimoto, Hiromi; Gehring, K.B.; Nikaido, Hiroshi; Carson, P.; Un, Sun; Klein, M.; Wemmer, D.E.

    1988-06-01

    In this paper we discuss the application of /sup 3/H NMR to biological problems. Two specific examples will be described; first, analysis of the binding of maltose to its transport protein from E. coli, called MBP; and second, following the glycolytic metabolism of glucose in erythrocytes. In both of these cases the unique properties of /sup 3/H for magnetic resonance make possible observations which are difficult with other methods. 4 refs., 2 figs.

  12. Characterization of (/sup 3/H)forskolin binding sites in the iris-ciliary body of the albino rabbit

    SciTech Connect

    Goldman, M.E.; Mallorga, P.; Pettibone, D.J.; Sugrue, M.F.

    1988-01-01

    (/sup 3/H)forskolin binding sites were identified using membranes prepared from the iris-ciliary body of adult, albino rabbits. Scatchard analysis of saturation binding experiments demonstrated that (/sup 3/H)forskolin bound to a single population of high affinity sites. The K/sub d/ and B/sub max/ values were 8.7 +- 0.9 nM and 119.0 +- 30.9 fmolmg prot. using membranes prepared from frozen tissue and 17.0 +- 6.2 nM and 184.4 +- 47.2 fmolmg prot. using fresh tissue. The binding of (/sup 3/H)forskolin was magnesium-dependent. The B/sub max/ was enhanced by sodium fluoride and Gpp(NH)p, a nonhydrolyzable guanine nucleotide analog. Forskolin was the most potent inhibitor of (/sup 3/H)forskolin binding; two commercially-available analogs were weaker inhibitors. In an adenylate cyclase assay, there was the same rank order of potency to enhance enzyme activity. Based upon binding affinities, magnesium-dependence, sensitivity to sodium fluoride and Gpp(NH)p, rank order of potencies of analogs and correlation of binding with adenylate cyclase activity, these studies suggest that the (/sup 3/H)forskolin binding site in the iris-ciliary body is similar to the binding site in other tissues

  13. Down-regulation of sup 3 H-imipramine binding sites in rat cerebral cortex prenatal exposure to antidepressants

    SciTech Connect

    Montero, D.; de Ceballos, M.L. ); Del Rio, J. )

    1990-01-01

    Several antidepressant drugs were given to pregnant rats in the last 15 days of gestation and {sup 3}H-imipramine binding ({sup 3}H-IMI) was subsequently measured in the cerebral cortex of the offspring. The selective serotonin (5-HT) uptake blockers chlorimipramine and fluoxetine as well as the selective monoamine oxidase (MAO) inhibitors clorgyline and deprenyl induced, after prenatal exposure, a down-regulation of {sup 3}H-IMI binding sites at postnatal day 25. The density of these binding sites was still reduced at postnatal day 90 in rats exposed in utero to the MAO inhibitors. The antidepressants desipramine and nomifensine were ineffective in this respect. After chronic treatment of adult animals, only chlorimipramine was able to down-regulate the {sup 3}H-IMI binding sites. Consequently, prenatal exposure of rats to different antidepressant drugs affecting predominantly the 5-HT systems induces more marked and long-lasting effects on cortical {sup 3}H-IMI binding sites. The results suggest that the developing brain is more susceptible to the actions of antidepressants.

  14. Biochemical characterization of high-affinity 3H-opioid binding. Further evidence for Mu1 sites

    SciTech Connect

    Nishimura, S.L.; Recht, L.D.; Pasternak, G.W.

    1984-01-01

    In saturation studies with (/sup 3/H)dihydromorphine, unlabeled D-Ala2-D-Leu5-enkephalin (1 nM) inhibited the high-affinity binding component far more potently than the lower-affinity one. Similarly, morphine (1 nM) inhibited the higher-affinity binding of /sup 3/H-D-Ala2-D-Leu5-enkephalin to a greater extent than its lower-affinity binding component, consistent with a common high-affinity binding site for opiates and enkephalins. Treatment of tissue with either trypsin (1 microgram/ml) or N-ethylmaleimide (25 microM) effectively eliminated the high-affinity binding component of a series of /sup 3/H-opiates and opioid peptides. Competition studies following both treatments were consistent with a common high-affinity binding site. Both treatments also eliminated the ability of low morphine concentrations (less than 1 nM) to inhibit /sup 3/H-D-Ala2-D-Leu5-enkephalin binding and of low D-Ala2-D-Leu5-enkephalin concentrations (less than 1 nM) to inhibit (/sup 3/H)dihydromorphine binding. Protection experiments examining N-ethylmaleimide (25 microM) inhibition of (/sup 3/H)dihydromorphine binding showed significant protection (p less than 0.002) by both unlabeled D-Ala2-D-Leu5-enkephalin and morphine (both at 1 nM). When studied together, both naloxonazine and N-ethylmaleimide inhibited (/sup 3/H)dihydromorphine binding to a similar extent. Equally important, tissue previously treated with naloxonazine was far less sensitive to N-ethylmaleimide than was untreated control tissue, consistent with the possibility that both treatments affected the same site. Together, these results support the concept of a common high-affinity binding site for opiates and opioid peptides.

  15. (/sup 3/H)muscimol binding sites increased in autopsied brains of chronic schizophrenics

    SciTech Connect

    Hanada, S.; Mita, T.; Nishino, N.; Tanaka, C.

    1987-01-19

    (/sup 3/H)muscimol binding and glutamic acid decarboxylase (GAD) activity in the prefrontal cortex and caudate nucleus of autopsied brains from 19 chronic schizophrenics and 17 control subjects were investigated. In the schizophrenics, saturation analysis with varying concentrations of (/sup 3/H)muscimol revealed an increase in the number GABA/sub A/ receptors, but there was no significant difference in the affinity. In addition, the enhancement of (/sup 3/H)muscimol binding by diazepam was significantly greater in schizophrenics than in controls. GAD activity did not differ between controls and schizophrenics. The possibility that GABAergic mechanisms might play a role in case of chronic schizophrenia should be given further attention.

  16. Autoradiographic imaging and quantification of the high-affinity GHB binding sites in rodent brain using (3)H-HOCPCA.

    PubMed

    Klein, A B; Bay, T; Villumsen, I S; Falk-Petersen, C B; Marek, A; Frølund, B; Clausen, R P; Hansen, H D; Knudsen, G M; Wellendorph, P

    2016-11-01

    GHB (γ-hydroxybutyric acid) is a compound endogenous to mammalian brain with high structural resemblance to GABA. GHB possesses nanomolar-micromolar affinity for a unique population of binding sites, but the exact nature of these remains elusive. In this study we utilized the highly selective GHB analogue, 3-hydroxycyclopent-1-enecarboxylic acid (HOCPCA) as a tritiated version ((3)H-HOCPCA) to radioactively label the specific GHB high-affinity binding site and gain further insight into the density, distribution and developmental profile of this protein. We show that, in low nanomolar concentrations, (3)H-HOCPCA displays excellent signal-to-noise ratios using rodent brain autoradiography, which makes it a valuable ligand for anatomical quantification of native GHB binding site levels. Our data confirmed that (3)H-HOCPCA labels only the high-affinity specific GHB binding site, found in high density in cortical and hippocampal regions. The experiments revealed markedly stronger binding at pH 6.0 (Kd 73.8 nM) compared to pH 7.4 (Kd 2312 nM), as previously reported for other GHB radioligands but similar Bmax values. Using (3)H-HOCPCA we analyzed the GHB binding protein profile during mouse brain development. Due to the high sensitivity of this radioligand, we were able to detect low levels of specific binding already at E15 in mouse brain, which increased progressively until adulthood. Collectively, we show that (3)H-HOCPCA is a highly sensitive radioligand, offering advantages over the commonly used radioligand (3)H-NCS-382, and thus a very suitable in vitro tool for qualitative and quantitative autoradiography of the GHB high-affinity site.

  17. In vitro and in vivo characterisation of [3H]ANSTO-14 binding to the sigma 1 binding sites.

    PubMed

    Nguyen, V H; Mardon, K; Kassiou, M; Christie, M D

    1999-02-01

    N-(4-phenylbutyl)-3-hydroxy-4-azahexacyclo[5.4.1.0(2,6).0(3, 10).0(5,9) .0(8,11)]dodecane (ANSTO-14) showed the highest activity for the sigma 1 site (Ki = 9.4 nM) and 19-fold sigma 1/sigma 2 selectivity. The present study showed that [3H]ANSTO-14 binds to a single high-affinity site in guinea pig brain membranes with an equilibrium Ki of 8.0 +/- 0.3 nM, in good agreement with the kinetic studies (Kd = 13.3 +/- 5.4 nM, n = 4), and a Bmax of 3.199 +/- 105 fmol/mg protein (n = 4). The in vivo biodistribution of [3H]ANSTO-14 showed a high uptake in the diencephalon. Pretreatment of rats with sigma ligands including (+)-pentazocine (sigma 1), ANSTO-14 (sigma 1), and DTG (sigma 1 and sigma 2) did not significantly reduce radiotracer uptake in the brain, but did in the spleen. A labelled metabolite was found in the liver and brain. Due to its insensitivity to sigma ligands, the accumulation of [3H]ANSTO-14 in the brain indicates high nonspecific binding. Therefore, [3H]ANSTO-14 is a suitable ligand for labelling sigma 1 sites in vitro but is not suitable for brain imaging of sigma binding sites in vivo.

  18. Different components of /sup 3/H-imipramine binding in rat brain membranes: relation to serotonin uptake sites

    SciTech Connect

    Gobbi, M.; Taddei, C.; Mennini, T.

    1988-01-01

    In the present paper, the authors confirm and extend previous studies showing heterogeneous /sup 3/H-imipramine (/sup 3/H-IMI) binding sites. Inhibition curves of various drugs (serotonin, imipramine, desmethyl-imipramine, d-fenfluramine, d-norfenfluramine and indalpine, a potent serotonin uptake inhibitor) obtained using 2 nM /sup 3/H-IMI and in presence of 120 mM NaCl, confirmed the presence of at least three /sup 3/H-IMI binding sites: two of these were serotonin-insensitive while the third one was selectively inhibited by serotonin and indalpine with nanomolar affinities. Moreover this last component was found to be selectively modulated by chronic imipramine treatment thus suggesting a close relation to serontonin uptake mechanism. These data indicate that the use of a more selective inhibitors of the serotonin-sensitive component (like indalpine or serotonin itself) to define non specific /sup 3/H-IMI, may be of help in understanding its relation with serotonin uptake system. 22 references, 2 figures, 2 tables.

  19. Solubilization and characterization of haloperidol-sensitive (+)-( sup 3 H)SKF-10,047 binding sites (sigma sites) from rat liver membranes

    SciTech Connect

    McCann, D.J.; Su, T.P. )

    1991-05-01

    The zwitterionic detergent 3-((3-cholamidopropyl)dimethylamino)-1-propanesulfonate (CHAPS) produced optimal solubilization of (+)-({sup 3}H)SKF-10,047 binding sites from rat liver membranes at a concentration of 0.2%, well below the critical micellular concentration of the detergent. The pharmacological selectivity of the liver (+)-({sup 3}H)SKF-10,047 binding sites corresponds to that of sigma sites from rat and guinea pig brain. When the affinities of 18 different drugs at (+)-({sup 3}H)SKF-10,047 binding sites in membranes and solubilized preparations were compared, a correlation coefficient of 0.99 and a slope of 1.03 were obtained, indicating that the pharmacological selectivity of rat liver sigma sites is retained after solubilization. In addition, the binding of 20 nM ({sup 3}H)progesterone to solubilized rat liver preparations was found to exhibit a pharmacological selectivity appropriate for sigma sites. A stimulatory effect of phenytoin on (+)-({sup 3}H)SKF-10,047 binding to sigma sites persisted after solubilization. When the solubilized preparation was subjected to molecular sizing chromatography, a single peak exhibiting specific (+)-({sup 3}H)SKF-10,047 binding was obtained. The binding activity of this peak was stimulated symmetrically when assays were performed in the presence of 300 microM phenytoin. The molecular weight of the CHAPS-solubilized sigma site complex was estimated to be 450,000 daltons. After solubilization with CHAPS, rat liver sigma sites were enriched to 12 pmol/mg of protein. The present results demonstrate a successful solubilization of sigma sites from rat liver membranes and provide direct evidence that the gonadal steroid progesterone binds to sigma sites. The results also suggest that the anticonvulsant phenytoin binds to an associated allosteric site on the sigma site complex.

  20. Characterization of (/sup 3/H)leukotriene D4 binding sites in guinea-pig ventricular myocardium

    SciTech Connect

    Hogaboom, G.K.; Mong, S.; Stadel, J.M.; Crooke, S.T.

    1985-06-01

    (/sup 3/H)Leukotriene (LT) D4 was used to identify specific LTD4 binding sites in guinea-pig ventricular myocardial membranes. High-performance liquid chromatography analyses indicated that, in the presence of the gamma-glutamyl transpeptidase inhibitor L-serine-borate (80 mM), less than 3% of membrane-bound (/sup 3/H)LTD4 was converted to (/sup 3/H)LTC4 or (/sup 3/H)LTE4 at 30 degrees C. The specific (/sup 3/H) LTD4 binding, assayed in the presence of 80 mM L-serine-borate, reached a stable steady state within 45 min at 30 degrees C (pH 7.5). A monophasic Scatchard plot of saturation binding data yielded an apparent dissociation constant (Kd) of 3.4 +/- 2.1 nM and a maximum number of binding sites of 850 +/- 91 fmol/mg of protein. Competition binding studies with (/sup 3/H)LTD4, synthetic 5S, 6R-LTD4 (LTD4) and its diastereoisomer 5R,6S-LTD4, LTE4, LTC4 and the putative LT antagonists FPL 55712, 4R-hydroxy-5S-1-cysteinylglycine-6Z-nonadecanoic acid (2-nor-LTD1) and SKF 88046 demonstrated a potency order of LTD4 greater than LTE4 greater than LTC4 greater than 5R,6S-LTD4 much greater than 2-nor-LTD1. FPL 55712 and SKF 88046 were ineffective in displacing the specific (/sup 3/H)LTD4 binding. Pretreatment of the heart membranes with the sulfhydryl reducing reagent dithiothreitol decreased the specific (/sup 3/H)LTD4 binding in a concentration-dependent manner. Scatchard analyses of saturation isotherms indicated that 0.3 mM dithiothreitol pretreatment of heart membranes decreased the maximum number of binding sites of the (/sup 3/H)LTD4 binding to 368 +/- 61 fmol/mg of protein with minimal effects on the apparent Kd.

  1. Characterization of specific binding sites for (/sup 3/H)(d)-N-allylnormetazocine in rat brain membranes

    SciTech Connect

    Itzhak, Y.; Hiller, J.M.; Simon, E.J.

    1985-01-01

    Binding of (/sup 3/H)(d)-N-allylnormetazocine ((/sup 3/H)(d)-NANM) to rat brain membranes is stereospecific, reversible, and saturable (Bmax . 260 fmol/mg of protein) and manifests moderately high affinity (Kd . 20 nM). The rank order of potency among opioidbenzomorphans and phencyclidine (PCP) analogs for competition for (/sup 3/H)(d)-NANM-binding sites is as follows: (d)-NANM . PCP-3-OH greater than (d)-cyclazocine greater than N-ethylphenylcyclohexylamine greater than PCP greater than (l)-cyclazocine . dextrorphan greater than (d/l)-ethylketocyclazocine greater than (d/l)-bremazocine greater than (1)-NANM greater than 1-phenylcyclohexylamine greater than levorphanol. Other opioid ligands, relatively selective for each of the types of opioid binding sites other than sigma, such as morphine (mu), H-Tyr-D-Ala(Me)Phe-NH-CH2-OH (mu), D-Ala2-D-Leu5-enkephalin (delta), tifluadom (kappa), and U 50488 (kappa) as well as etorphine and naloxone were all unable to compete with (/sup 3/H)(d)-NANM for specific binding even at a concentration of 1 microM. Regional distribution studies of (/sup 3/H)(d)-NANM-binding sites show high density in the hippocampus, thalamus, hypothalamus, and amygdala and low density in cerebellum and nonfrontal neocortex membranes of the rat brain. These binding sites are very sensitive to protein-modifying enzymes and reagents such as trypsin and N-ethylmaleimide and to heat denaturation. These results provide direct biochemical evidence for the existence of distinct (d)-NANM-binding sites in rat brain.

  2. Downregulation of (3H)Ro5-4864 binding sites after exposure to peripheral-type benzodiazepines in vitro

    SciTech Connect

    Johnson, M.D.; Wang, J.K.; Morgan, J.I.; Spector, S.

    1986-09-01

    Peripheral-type benzodiazepine (BZD) binding sites undergo a rapid and pronounced downregulation after exposure to these compounds in vitro. Friend erythroleukemia cells were incubated with micromolar concentrations of BZD after which they were washed thoroughly and the binding of the specific peripheral-type BZD radioligand (/sup 3/H)Ro5-4864 was determined. Exposure to the peripheral-type BZD Ro7-3351 decreased the number of (/sup 3/H)Ro5-4864 binding sites from 324 to 41 fmol/10(6) cells with no change in affinity. Downregulation appears to require active cellular processes because it is blocked when exposure to BZD is at 4/sup 0/C rather than at 37/sup 0/C. Furthermore, whereas (/sup 3/H)Ro5-4864 binding is decreased substantially in membrane preparations made from downregulated cells, it is not altered when membrane preparations from control cells are exposed to BZD. The time course of downregulation is quite rapid, as it occurs within minutes. In contrast, the return of sites requires days and there is a close relationship between return of sites and growth of new cells. The ability of BZDs to downregulate correlates more closely with affinity for the peripheral-type site than with biological activity. The ability to undergo downregulation is characteristic of receptors and its occurrence suggests that peripheral-type BZD binding sites are functional receptors.

  3. Symmetry breaking in binary chains with nonlinear sites

    NASA Astrophysics Data System (ADS)

    Maksimov, Dmitrii N.; Sadreev, Almas F.

    2013-09-01

    We consider a system of two or four nonlinear sites coupled with binary chain waveguides. When a monochromatic wave is injected into the first (symmetric) propagation channel, the presence of cubic nonlinearity can lead to symmetry breaking, giving rise to emission of antisymmetric wave into the second (antisymmetric) propagation channel of the waveguides. We found that in the case of nonlinear plaquette, there is a domain in the parameter space where neither symmetry-preserving nor symmetry-breaking stable stationary solutions exit. As a result, injection of a monochromatic symmetric wave gives rise to emission of nonsymmetric satellite waves with energies differing from the energy of the incident wave. Thus, the response exhibits nonmonochromatic behavior.

  4. Measuring the serotonin uptake site using (/sup 3/H)paroxetine--a new serotonin uptake inhibitor

    SciTech Connect

    Gleiter, C.H.; Nutt, D.J.

    1988-01-01

    Serotonin is an important neurotransmitter that may be involved in ethanol preference and dependence. It is possible to label the serotonin uptake site in brain using the tricyclic antidepressant imipramine, but this also binds to other sites. We have used the new high-affinity uptake blocker paroxetine to define binding to this site and report it to have advantages over imipramine as a ligand.

  5. Differential effect of detergents on (/sup 3/H)Ro 5-4864 and (/sup 3/H)PK 11195 binding to peripheral-type benzodiazepine-binding sites

    SciTech Connect

    Awad, M.; Gavish, M.

    1988-01-01

    The present study demonstrates a differential effect of various detergent treatments on (/sup 3/H)Ro 5-4864 and (/sup 3/H)PK 11195 binding to peripheral benzodiazepine binding sites (PBS). Triton X-100 caused a decrease of about 70% in (/sup 3/H)Ro 5-4864 binding to membranes from various peripheral tissues of rat, but had only a negligible effect on (/sup 3/H)PK 11195 binding. A similar effect of Triton X-100 was observed on guinea pig and rabbit kidney membranes. The decrease in (/sup 3/H)Ro 5-4864 binding after treatment with Triton X-100 was apparently due to a decrease in the density of PBS, since the affinity remained unaltered. The detergents 3-((3-cholamidopropyl)-dimethylammonio)-1-propane sulfonate (CHAPS), Tween 20, deoxycholic acid, or digitonin (0.0125%) caused only a minor change in (/sup 3/H)Ro 5-4864 and (/sup 3/H)PK 11195 binding to rat kidney membranes; but when concentrations were substantially increased (0.1%), all detergents caused a decrease of at least 50% in (/sup 3/H)Ro 5-4864 binding, while (/sup 3/H)PK 11195 binding to rat kidney membranes remained unaffected by the first three detergents, with only a minor decrease (15%) after treatment with digitonin.

  6. Binding of [(3)H]lysergic acid diethylamide to serotonin 5-HT(2A) receptors and of [(3)H]paroxetine to serotonin uptake sites in platelets from healthy children, adolescents and adults.

    PubMed

    Sigurdh, J; Spigset, O; Allard, P; Mjörndal, T; Hägglöf, B

    1999-11-01

    Possible age effects on binding of [(3)H]lysergic acid diethylamide ([(3)H]LSD) to serotonin 5-HT(2A) receptors and of [(3)H]paroxetine to serotonin uptake sites were studied in platelets from healthy children (11-12 years of age), adolescents (16-17 years of age) and adults. Significant overall age effects were found both for the number of binding sites (B(max)) for [(3)H]LSD binding (p < 0.001), the affinity constant (K(d)) for [(3)H]LSD binding (p < 0.001), B(max) for [(3)H]paroxetine binding (p < 0.001) and K(d) for [(3)H] paroxetine binding (p = 0.006). In general, there was a decrease in B(max) with increasing age, which predominantly occurred between the ages 11-12 years and 16-17 years for the 5-HT(2A) receptor, and after 16-17 years of age for the serotonin uptake site. These developmental changes might have an impact on the effect of treatment with serotonergic drugs in children and adolescents. When the platelet serotonin variables investigated are employed in studies in children or adolescents, age matching or, alternatively, introduction of age control in the statistical analysis should be performed.

  7. Desformylflustrabromine (dFBr) and [3H]dFBr-Labeled Binding Sites in a Nicotinic Acetylcholine Receptor

    PubMed Central

    Hamouda, Ayman K.; Wang, Ze-Jun; Stewart, Deirdre S.; Jain, Atul D.; Glennon, Richard A.

    2015-01-01

    Desformylflustrabromine (dFBr) is a positive allosteric modulator (PAM) of α4β2 and α2β2 nAChRs that, at concentrations >1 µM, also inhibits these receptors and α7 nAChRs. However, its interactions with muscle-type nAChRs have not been characterized, and the locations of its binding site(s) in any nAChR are not known. We report here that dFBr inhibits human muscle (αβεδ) and Torpedo (αβγδ) nAChR expressed in Xenopus oocytes with IC50 values of ∼1 μM. dFBr also inhibited the equilibrium binding of ion channel blockers to Torpedo nAChRs with higher affinity in the nAChR desensitized state ([3H]phencyclidine; IC50 = 4 μM) than in the resting state ([3H]tetracaine; IC50 = 60 μM), whereas it bound with only very low affinity to the ACh binding sites ([3H]ACh, IC50 = 1 mM). Upon irradiation at 312 nm, [3H]dFBr photoincorporated into amino acids within the Torpedo nAChR ion channel with the efficiency of photoincorporation enhanced in the presence of agonist and the agonist-enhanced photolabeling inhibitable by phencyclidine. In the presence of agonist, [3H]dFBr also photolabeled amino acids in the nAChR extracellular domain within binding pockets identified previously for the nonselective nAChR PAMs galantamine and physostigmine at the canonical α-γ interface containing the transmitter binding sites and at the noncanonical δ-β subunit interface. These results establish that dFBr inhibits muscle-type nAChR by binding in the ion channel and that [3H]dFBr is a photoaffinity probe with broad amino acid side chain reactivity. PMID:25870334

  8. ( sup 3 H)opipramol labels a novel binding site and sigma receptors in rat brain membranes

    SciTech Connect

    Ferris, C.D.; Hirsch, D.J.; Brooks, B.P.; Snowman, A.M.; Snyder, S.H. )

    1991-02-01

    Opipramol (OP), a clinically effective antidepressant with a tricyclic structure, is inactive as an inhibitor of biogenic amine uptake. ({sup 3}H)Opipramol binds saturably to rat brain membranes (apparent KD = 4 nM, Bmax = 3 pmol/mg of protein). ({sup 3}H)Opipramol binding can be differentiated into haloperidol-sensitive and -resistant components, with Ki values for haloperidol of 1 nM (Bmax = 1 pmol/mg of protein) and 350 nM (Bmax = 1.9 pmol/mg of protein), respectively. The drug specificity of the haloperidol-sensitive component is the same as that of sigma receptors labeled with (+)-({sup 3}H)3-(3-hydroxyphenyl)-N-(1-propyl)piperdine. The haloperidol-resistant component does not correspond to any known neurotransmitter receptor or uptake recognition site. It displays high affinity for phenothiazines and related structures such as perphenazine, clopenthixol, and flupenthixol, whose potencies are comparable to that of opipramol. Because certain of these drugs are more potent at the haloperidol-resistant opipramol site than in exerting any other action, it is possible that this opipramol-selective site may mediate their therapeutic effects.

  9. Subcellular distribution of ( sup 3 H)-dexamethasone mesylate binding sites in Leydig cells using electron microscope radioautography

    SciTech Connect

    Stalker, A.; Hermo, L.; Antakly, T. )

    1991-01-01

    The present view is that glucocorticoid hormones bind to their cytoplasmic receptors before reaching their nuclear target sites, which include specific DNA sequences. Although it is believed that cytoplasmic sequestration of steroid receptors and other transcription factors (such as NFKB) may regulate the overall activity of these factors, there is little information on the exact subcellular sites of steroid receptors or even of any other transcription factors. Tritiated (3H)-dexamethasone 21-mesylate (DM) is an affinity label that binds covalently to the glucocorticoid receptor (GR), thereby allowing morphological localization of the receptor at the light and electron microscope levels as well as for quantitative radioautographic (RAG) analysis. After injection of 3H-DM into the testis, a specific radioautographic signal was observed in Leydig cells, which correlated with a high level of immunocytochemically demonstrable GR in these cells at the light-microscope level. To localize the 3H-DM binding sites at the electron microscope (EM) level, the testes of 5 experimental and 3 control adrenalectomized rats were injected directly with 20 microCi 3H-DM; control rats received simultaneously a 25-fold excess of unlabeled dexamethasone; 15 min later, rats were fixed with glutaraldehyde and the tissue was processed for EM RAG analysis combined with quantitative morphometry. The radioautographs showed that the cytosol, nucleus, smooth endoplasmic reticulum (sER), and mitochondria were labeled. Since the cytosol was always adjacent to tubules of the sER, the term sER-rich cytosol was used to represent label over sER networks, which may also represent cytosol labeling due to the limited resolution of the radioautographic technique. Labeling was highest in sER-rich cytosol and mitochondria, at 53% and 31% of the total, respectively.

  10. Quantitative autoradiographic distribution of [3H]mazindol-labeled dopamine uptake sites in the brains of superoxide dismutase transgenic mice.

    PubMed

    Cadet, J L; Przedborski, S; Kostic, V; Jackson-Lewis, V; Carlson, E; Epstein, C J

    1990-07-01

    Superoxide dismutase (SOD) is an important enzyme which is involved in the dismutation of the toxic radical, superoxide anion. The activity of CuZnSOD is increased in patients who suffer from Down's Syndrome, Alzheimer's disease, and in Parkinson's disease. In order to evaluate the contribution of this enzyme to the neuropathology of these neurodegenerative diseases, transgenic mice have been constructed which express the human CuZnSOD gene. As a first step towards exploring these issues, we have carried out an autoradiographic binding study of the distribution of the catecholaminergic uptake blocker mazindol in the brain of these transgenic mice and of their littermates. Desmethylimipramine (DMI)-insensitive [3H]mazindol binding sites which correspond to dopamine uptake sites were located in the striatum, the nucleus accumbens, the olfactory tubercle and in the substantia nigra. Within the striatum, there was a lateromedial gradient, with higher concentration of dopamine uptake sites being found laterally. These findings suggest that subregions of the basal ganglia may be more susceptible to the deleterious effects of dopaminotoxic drugs which are taken up into the dopaminergic neurons via these uptake sites. Saturation experiments revealed no differences in the characteristics of [3H]mazindol binding sites between the two groups of mice. Thus, increased activity of SOD is not associated with diffuse changes in the molecular structures of receptors in mice brain.

  11. Binding of [3H]paroxetine to serotonin uptake sites and of [3H]lysergic acid diethylamide to 5-HT2A receptors in platelets from women with premenstrual dysphoric disorder during gonadotropin releasing hormone treatment.

    PubMed

    Bixo, M; Allard, P; Bäckström, T; Mjörndal, T; Nyberg, S; Spigset, O; Sundström-Poromaa, I

    2001-08-01

    Changes in serotonergic parameters have been reported in psychiatric conditions such as depression but also in the premenstrual dysphoric disorder (PMDD). In addition, hormonal effects on serotonergic activity have been established. In the present study, binding of [3H]paroxetine to platelet serotonin uptake sites and binding of [3H]lysergic acid diethylamide ([3H]LSD) to platelet serotonin (5-HT)2A receptors were studied in patients with PMDD treated with a low dose of a gonadotropin releasing hormone (GnRH) agonist (buserelin) or placebo and compared to controls. The PMDD patients were relieved of premenstrual symptoms like depression and irritability during buserelin treatment. The number of [3H]paroxetine binding sites (Bmax) were significantly higher in the follicular phase in untreated PMDD patients compared to controls. When treated with buserelin the difference disappeared. No differences in [3H]LSD binding between the three groups were shown. The present study demonstrated altered platelet [3H]paroxetine binding characteristics in women with PMDD compared to controls. Furthermore, [3H]paroxetine binding was affected by PMDD treatment with a low dose of buserelin. The results are consistent with the hypothesis that changes in serotonergic transmission could be a trait in the premenstrual dysphoric disorder.

  12. Increased /sup 3/H-spiperone binding sites in mesolimbic area related to methamphetamine-induced behavioral hypersensitivity

    SciTech Connect

    Akiyama, K.; Sato, M.; Otsuki, S.

    1982-02-01

    The specific /sup 3/H-spiperone binding to membrane homogenates of the striatum, mesolimbic area, and frontal cortex was examined in two groups of rats pretreated once daily with saline or 4 mg/kg of methamphetamine (MAP) for 14 days. At 7 days following cessation of chronic pretreatment, all rats received an injection of 4 mg/kg of MAP and were decapitated 1 hr after the injection. In the chronic saline-pretreatment group, the single administration of MAP induced significant changes in the number (Bmax) of specific /sup 3/H-spiperone binding sites (a decrease in the striatum and an increase in the mesolimbic area and frontal cortex), but no significant changes in the affinity (KD) in any brain area. The chronic MAP pretreatment markedly augmented the changes in Bmax in the striatum and mesolimbic area. The increase in specific /sup 3/H-spiperone binding sites in the mesolimbic area is discussed in relation to MAP-induced behavioral hypersensitivity.

  13. Site Sensitivity and local electronic symmetries in carboranes

    NASA Astrophysics Data System (ADS)

    Fister, T. T.; Seidler, G. T.; Vila, F. D.; Cross, J. O.; Linehan, J. C.

    2007-03-01

    Icosohedral carboranes containing ten boron and two carbon atoms are seeing renewed interest because of their potential use in new cancer and AIDS therapies. These molecules have flexible geometries which allow bonding to three types of carbon sites (e.g. ortho-, para-, and meta- configurations). Using a new multielement spectrometer, we present the first x-ray Raman scattering (XRS) study on each isomer with excited state spectra taken from the both the carbon and boron 1s states. The change in the electronic structure between the isomers is most pronounced in the carbon spectrum, where the position in the edge confirms prior density functional theory calculations. With the boron spectra, we used the unique momentum transfer dependence of XRS to extract the symmetry components of the density of unoccupied states, i.e. the l-DOS. These results give an improved picture of the local electronic properties of the carboranes.

  14. Autoradiographic localization of sigma receptor binding sites in guinea pig and rat central nervous system with (+)3H-3-(3-hydroxyphenyl)-N-(1-propyl)piperidine

    SciTech Connect

    Gundlach, A.L.; Largent, B.L.; Snyder, S.H.

    1986-06-01

    (+)3H-3-PPP ((+)3H-3-(3-Hydroxyphenyl)-N-(1-propyl)-piperidine) binds with high affinity to brain membranes with a pharmacological profile consistent with that of sigma receptors. The distribution of (+)3H-3-PPP binding sites in brain and spinal cord of both guinea pig and rat has been determined by in vitro autoradiography with binding densities quantitated by computer-assisted densitometry. (+)3H-3-PPP binding to slide-mounted brain sections is saturable and displays high affinity and a pharmacological specificity very similar to sites labeled in homogenates. (+)3H-3-PPP binding sites are heterogeneously distributed. Highest concentrations of binding sites occur in spinal cord, particularly the ventral horn and dorsal root ganglia; the pons-medulla, associated with the cranial nerve and pontine nuclei and throughout the brain stem reticular formation; the cerebellum, over the Purkinje cell layer; the midbrain, particularly the central gray and red nucleus; and hippocampus, over the pyramidal cell layer. Lowest levels are seen in the basal ganglia and parts of the thalamus, while all other areas, including hypothalamus and cerebral cortex, exhibit moderate grain densities. Quinolinic acid-induced lesions of the hippocampus indicate that (+)3H-3-PPP labels hippocampal pyramidal cells and granule cells in the dentate gyrus. Intrastriatal injection of ibotenic acid dramatically reduces (+)3H-3-PPP binding in this area, while injection of 6-hydroxydopamine produces a relatively slight decrease. The distribution of (+)3H-3-PPP binding sites does not correlate with the receptor distribution of any recognized neurotransmitter or neuropeptide, including dopamine. However, there is a notable similarity between the distribution of (+)3H-3-PPP sites and high-affinity binding sites for psychotomimetic opioids, such as the benzomorphan (+)SKF 10,047.

  15. Characterization and distribution of binding sites for a new neurotensin receptor antagonist ligand, [3H]SR 48692, in the guinea pig brain1

    PubMed Central

    Betancur, Catalina; Canton, Maryse; Gully, Danielle; Vela, Gema; Pélaprat, Didier; Rostène, William

    1995-01-01

    SR 48692, a selective non-peptide antagonist of neurotensin (NT) receptors was recently developed. In the present work we studied the binding properties of the corresponding radioligand, 3H-SR 48692, in the adult guinea-pig brain. The characterization of 3H-SR 48692 binding was carried out on brain membrane preparations and the distribution of 3H-SR 48692 binding sites was determined by receptor autoradiography, and compared to that of 125I-NT binding sites. In brain homogenates, 3H-SR 48692 bound to a single population of sites with a Kd of 2.19 nM and a Bmax of 1.15 pmol/mg protein. This Bmax value was 20 times higher than that observed for 125I-NT. NT agonists were able to competitively interact with the entire population of binding sites labeled by 3H-SR 48692, but their affinities were much lower than those observed for 125I-NT. By contrast, NT antagonists exhibited similar abilities to inhibit the binding of both radioligands. The addition of unlabeled NT in saturation assays revealed a competitive inhibition of 3H-SR 48692 binding, suggesting that agonist and antagonists ligands bind to overlapping domains of the NT receptor. The autoradiographic distribution of the low-affinity NT binding sites detected by 3H-SR 48692 (96% of the receptors) was very similar to the distribution of high-affinity receptors labeled with 125I-NT (4% of the receptors). In addition, the binding of 3H-SR 48692 was insensitive to guanyl nucleotides. Taken together, these findings suggest that the binding sites detected by 3H-SR 48692 in the guinea-pig brain mainly represent the uncoupled form of the NT receptor. PMID:7791120

  16. Direct photoaffinity labeling of gizzard myosin with ( sup 3 H)uridine diphosphate places Glu185 of the heavy chain at the active site

    SciTech Connect

    Garabedian, T.E.; Yount, R.G. )

    1990-12-25

    The active site of chicken gizzard myosin was labeled by direct photoaffinity labeling with ({sup 3}H)UDP. ({sup 3}H) UDP was stably trapped at the active site by addition of vanadate (Vi) and Co{sup 2+}. The extraordinary stability of the myosin.Co2+.(3H)UDP.Vi complex (t1/2 greater than 5 days at 0{degrees}C) allowed it to be purified free of extraneous ({sup 3}H)UDP before irradiation began. Upon UV irradiation, greater than 60% of the trapped ({sup 3}H)UDP was photoincorporated into the active site. Only the 200-kDa heavy chain was labeled, confirming earlier results using ({sup 3}H)UTP. Extensive tryptic digestion of photolabeled myosin subfragment 1 followed by high performance liquid chromatography separations and removal of nucleotide phosphates by treatment with alkaline phosphatase allowed two labeled peptides to be isolated. Sequencing of the labeled peptides and radioactive counting showed that Glu185 was the residue labeled. Since UDP is a zero-length cross-linker, Glu185 is located at the purine-binding pocket of the active site of smooth myosin and adjacent to the glycine-rich loop which binds the polyphosphate portion of ATP. This Glu residue is conserved in smooth and nonmuscle myosins and is the same residue identified previously by ({sup 3}H)UTP photolabeling in Acanthamoeba myosin II.

  17. The (--)(/sup 3/H)dihydroalprenolol binding to rat adipocyte membranes: an explanation of curvilinear Scatchard plots and implications for quantitation of beta-adrenergic sites

    SciTech Connect

    Dax, E.M.; Partilla, J.S.; Gregerman, R.I.

    1982-09-01

    In rat adipocyte membranes, both beta-adrenergic agonists and beta-adrenergic antagonists competed with (--)(/sup 3/H)dihydroalprenolol for high affinity (KD 2-4 nM) and low capacity binding sites. The antagonists but not the agonists competed with (--)(/sup 3/H)dihydroalprenolol for lower affinity and higher capacity sites. The present studies were performed in order to characterize the adipocyte beta-adrenergic receptor and distinguish it from low affinity, higher capacity sites which were heat-labile and not stereoselective. When isoproterenol was used to define the nonspecific binding, saturation studies showed a single binding site with a capacity of approximately 100 fmol/mg membrane protein (corresponding to approximately 50,000 sites/adipocyte). Binding was saturated by 10 nM (--)(/sup 3/H)dihydroalprenolol. Approximate KD's of 204 nM were observed. Kinetic analysis of (--)(/sup 3/H)dihydroalprenolol binding provided an independent measurement of KD between 0.75 and 1.1 nM. This binding site had the characteristics of a beta 1-adrenergic receptor with the potency of isoproterenol greater than norepinephrine greater than or equal to epinephrine as competitors of binding. Furthermore, the KD of inhibition of (--)(/sup 3/H)dihydroalprenolol binding correlated with the Ki of inhibition by antagonists or Ka of activation by agonists of glycerol release in isolated adipocytes (r . 0.968, P less than 0.001). These results suggest that beta-adrenergic agonists compete with (--)(/sup 3/H)dihydroalprenolol for the high affinity binding site which represents the physiological site. Furthermore, the use of antagonists (propranolol, alprenolol) to define specific beta-binding includes nonspecific site(s) as well as the beta-adrenergic site. Previous characterization and quantitation of beta receptors in rat fat cell membranes may have been in error by incorporating both types of binding in their measurement.

  18. Competitive interaction of agonists and antagonists with 5-HT3 recognition sites in membranes of neuroblastoma cells labelled with (/sup 3/H)ICS 205-930

    SciTech Connect

    Hoyer, D.; Neijt, H.C.; Karpf, A.

    1989-01-01

    (3H)ICS 205-930 labelled 5-HT3 recognition sites in membranes prepared from murine neuroblastoma N1E-115 cells. Binding was rapid, reversible, saturable and stereoselective to an apparently homogeneous population of sites. Kinetic studies revealed that agonists and antagonists produced a monophasic dissociation reaction of (3H)ICS 205-930 from its recognition sites. The dissociation rate constant of the radioligand was similar whether the dissociation was induced by an agonist or an antagonist. Competition studies carried out with agonists and antagonists also suggested the presence of a homogeneous population of (3H)ICS 205-930 recognition sites. Competition curves were best fit for a 1 site model. (3H)ICS 205-930 binding sites displayed the pharmacological profile of a 5-HT3 receptor. The interactions of agonists and antagonists with (3H)ICS 205-930 recognition sites were apparently competitive in nature, as demonstrated in kinetic and equilibrium experiments. In saturation experiments carried out with (3H)ICS 205-930 in the presence and the absence of unlabelled agonists and antagonists, apparent Bmax values were not reduced whereas apparent Kd values were increased in the presence of competing ligands. There was a good agreement between apparent pKB values calculated for the competing ligands in saturation experiments and pKd values calculated from competition experiments. The present data demonstrate that (3H)ICS 205-930 labels a homogeneous population of sites at which agonists and antagonists interact competitively.

  19. Distinction between high-affinity (/sup 3/H)phencyclidine binding sites and muscarinic receptors in guinea-pig ileum muscle

    SciTech Connect

    El-Fakahany, E.E.; Triggle, D.J.; Eldefrawi, A.T.; Eldefrawi, M.E.

    1984-05-01

    (/sup 3/H)Phencyclidine ((/sup 3/H)PCP) binding was studied in guinea-pig ileum muscle membranes. Specific binding of (/sup 3/H)PCP was time dependent, reversible and saturable, with an equilibrium dissociation constant of 154 nM and maximum binding of 12.9 pmol/mg of protein at pH 9. Its pH dependency suggests that the un-ionized PCP is the pharmacologically active form. The binding site was on a protein which was sensitive to heat, proteolytic enzymes and the carboxylic group reagent dicyclohexylcarbodiimide, but insensitive to phospholipase A and C, concanavalin A, dithiothreitol and N-ethylmaleimide. Specific (/sup 3/H)PCP binding was displaced effectively by several PCP analogs and Ca/sup + +/ channel antagonists including verapamil, to which these sites had a high affinity. These high-affinity PCP-binding sites were found at a much higher concentration in the same membrane preparation than muscarinic receptor sites identified by their specific binding of (/sup 3/H)quinuclidinyl benzilate. PCP bound to both sites, but with a lower affinity to the muscarinic receptor sites. The PCP and muscarinic receptor sites differed in their sensitivities to pH and drug specifities.

  20. Binding of a Calcium Antagonist, [3H]Nitrendipine, to High Affinity Sites in Bovine Aortic Smooth Muscle and Canine Cardiac Membranes

    PubMed Central

    Williams, Lewis T.; Tremble, Patrice

    1982-01-01

    [3H]Nitrendipine, a potent calcium channel antagonist [3-ethyl-5-methyl-1-1,4-dihydro-2,6 - dimethyl - 4 - (3 - nitrophenyl) - 3,5 - pyridine carboxylate], was used to label high affinity binding sites on membranes prepared from bovine aortic smooth muscle. The binding of [3H]nitrendipine is rapid (t1/2 < 5 min) and reversible at 37°C. The binding sites have a high affinity for [3H]nitrendipine with an equilibrium dissociation constant of 2.1 nM. The density of sites is 40-60 fmol/mg of membrane protein. Analogues of nitrendipine compete for the binding sites with affinities consistent with their known biological effects as calcium antagonists. Nisoldipine, [isobutyl methyl 1,4-dihydro-2,6-dimethyl-4-(2-nitrophenyl)-3,5-pyridine carboxylate], a calcium antagonist more potent than nifedipine [2,6-dimethyl-3,5-dicarbomethoxy-4-(2-nitrophenyl)-1,4-dihydropyridine] in relaxing vascular smooth muscle, has an affinity three-fold higher than that of nifedipine in competing for the binding sites. A biologically inactive derivative of nifedipine does not compete for [3H]nitrendipine binding. Verapamil (α-isopropyl-α[(N-methyl - N-homoveratryl) -α-aminopropyl]-3,4-dimethyoxyphenyl acetonitrile), a structurally different calcium antagonist, only partially (25%) inhibits binding at high concentrations (1 μM). Prazosin, an alpha adrenergic antagonist does not compete for [3H]nitrendipine binding sites. The binding of [3H]nitrendipine is not affected by 1.5 mM calcium. Canine cardiac membranes also have high affinity [3H]nitrendipine binding sites, (KD = 6 nM) but bovine erythrocytes do not. The relative affinities of nisoldipine and nifedipine for the cardiac membrane binding sites reflect the relative activities of these compounds as calcium channel antagonists. These results suggest that the [3H]nitrendipine binding sites are the sites through which dihydropyridines act as calcium channel antagonists. PMID:6282938

  1. The novel alpha 2-adrenoceptor agonist [3H]mivazerol binds to non-adrenergic binding sites in human striatum membranes that are distinct from imidazoline receptors.

    PubMed

    Flamez, A; Gillard, M; De Backer, J P; Vauquelin, G; Noyer, M

    1997-07-01

    The alpha 2 adrenergic agonist [3H]mivazerol labelled two populations of binding sites in membranes from the human striatum. Forty per cent of the sites labelled by 3 nM [3H]mivazerol corresponded to alpha 2 adrenergic receptors as they displayed a high affinity for (-)-adrenaline and for rauwolscine. The remaining binding was displaced by mivazerol with a pIC50 of 6.5 +/- 0.1. These sites displayed higher affinity for dexmedetomidine (pIC50 = 7.1 +/- 0.1), but much lower affinity for clonidine (pIC50 < 5.0) and for idazoxan (pIC50 = 5.1 +/- 0.1). Mivazerol also showed low affinity for the [3H]clonidine-labelled I1 imidazoline receptors and for the [3H]idazoxan-labelled I2 receptors (pIC50 = 5.1 and 3.9, respectively). These results suggest that the non-adrenergic [3H]mivazerol binding sites are distinct from the imidazoline receptors in the human striatum.

  2. Sodium-dependent high-affinity binding of (/sup 3/H)hemicholinium-3 in the rat brain: a potentially selective marker for presynaptic cholinergic sites

    SciTech Connect

    Vickroy, T.W.; Roeske, W.R.; Yamamura, H.I.

    1984-12-03

    An attempt has been made to describes the membrane binding properties of (/sup 3/H)hemicholinium-3 ((/sup 3/H)HC-3), a selective inhibitor of sodium-dependent high-affinity choline uptake (SDHACU) in cholinergic nerve terminals. Under the described assay conditions. (/sup 3/H)HC-3 binds with a saturable population of high-affinity (apparent K/sub d/ = 1.9 nM CNS membrane sites having the regional distribution: striatum >> hippocampus > cerebral cortex > cerebellum. High-affinity (/sup 3/H)HC-3 binding is entirely dependent upon the presence of sodium chloride (EC/sub 50/ = 35-50 mM) and is markedly reduced when other salts of sodium or monovalent ions are substituted. (/sup 3/H)HC-3 binding is inhibited by choline (K/sub i/ = 6..mu..M) and acetylcholine (K/sub i/ = 35..mu..M) but markedly less sensitive to other cholinergic agents and metabolic inhibitors. In light of the similar ionic dependencies, regional distributions and pharmacological specificities of (/sup 3/H)HC-3 binding and SDHACU, closely associated sites may be involved in both processes. 2 references, 3 figures, 3 tables.

  3. Specific /sup 3/H-DMCM binding to a non-benzodiazepine binding site after silver ion treatment of rat brain membranes

    SciTech Connect

    Honore, T.; Nielsen, M.; Braestrup, C.

    1984-11-26

    Specific binding of the BZ-receptor ligand /sup 3/H-DMCM to rat cortical membranes was dramatically enhanced by preincubation of the homogenate with 0.1 mM silver (Ag/sup +/) nitrate. The binding was completely inhibited by midazolam. Nevertheless, the pharmacological specificity of the Ag/sup +/-enhanced /sup 3/H-DMCM binding was different from that of BZ-receptors. Furthermore, the B/sub max/ value, the regional distribution and the molecular target size determined by radiation inactivation analysis of the Ag/sup +/-enhanced binding site were different from those of BZ-receptors. The results indicate that Ag/sup +/-enhanced /sup 3/H-DMCM binding represent a high affinity metal complex formation between /sup 3/H-DMCM and an unknown brain specific protein of approximately 100,000 daltons molecular weight. 11 references, 3 figures, 4 tables.

  4. Mapping of the acetylcholine binding site of the nicotinic acetylcholine receptor: ( sup 3 H)nicotine as an agonist photoaffinity label

    SciTech Connect

    Middleton, R.E.; Cohen, J.B. )

    1991-07-16

    The agonist ({sup 3}H)nicotine was used as a photoaffinity label for the acetylcholine binding sties on the Torpedo nicotinic acetylcholine receptor (AChR). ({sup 3}H)Nicotine binds at equilibrium with K{sub eq} = 0.6 {mu}M to the agonist binding sites. Irradiation with 254-nm light of AChR-rich membranes equilibrated with ({sup 3}H)nicotine resulted in covalent incorporation into the {alpha}- and {gamma}-subunits, which was inhibited by agonists and competitive antagonists but not by noncompetitive antagonists. Inhibition of labeling by d-tubocurarine demonstrated that the {alpha}-subunit was labeled via both agonist sites but the {gamma}-subunit was labeled only via the site that binds d-tubocurarine with high affinity. Chymotryptic digestion of the {alpha}-subunit confirmed that Try-198 was the principal amino acid labeled by ({sup 3}H)nicotine. This confirmation required a novel radiosequencing strategy employing o-phthalaldehyde ({sup 3}H)Nicotine, which is the first photoaffinity agonist used, labels primarily Tyr-198 in contrast to competitive antagonist affinity labels, which label primarily Tyr-190 and Cys-192/Cys-193.

  5. Irreversible blockade of the high and low affinity ( sup 3 H) naloxone binding sites by C-6 derivatives of morphinane-6-ones

    SciTech Connect

    Krizsan, D. ); Varga, E.; Benyhe, S.; Szucs, M.; Borsodi, A. ); Hosztafi, S. )

    1991-01-01

    C-6 derivatives-hydrazones, phenylhydrazones, dinitrophenylhydrazones, oximes and semicarbazones - of morphinane-6-ones were synthesized and their binding characteristics were studied on rat brain membranes. The dihydromorphinone and oxymorphone derivatives compete for the ({sup 3}H)naloxone binding sites with high affinity, while the dihydrocodeinone and oxycodone derivatives are less potent. The affinity of the new compounds is decreased for the delta sites as compared to the parent ligands. The ligands bearing bulky substituents also bind with low affinity to the kappa sites. The modification decreased the Na{sup +}-index of compounds indicating their mixed agonist-antagonist character. The dihydromorphinone derivatives are all capable to block irreversibly the high affinity binding site of ({sup 3}H)naloxone, whereas the dihydrocodeinone derivatives block irreversibly the low affinity site. A possible mechanism for the inhibition is suggested.

  6. Structure of the high-affinity binding site for noncompetitive blockers of the acetylcholine receptor: (/sup 3/H)chlorpromazine labels homologous residues in the. beta. and delta chains

    SciTech Connect

    Giraudat, J.; Dennis, M.; Heidmann, T.; Haumont, P.Y.; Lederer, F.; Changeux, J.P.

    1987-05-05

    The membrane-bound acetylcholine receptor from Torpedo marmorata was photolabeled by the noncompetitive channel blocker (/sup 3/H)chlorpromazine under equilibrium conditions in the presence of the agonist carbamoylcholine. The amount of radioactivity incorporated into all subunits was reduced by addition of phencyclidine, a specific ligand for the high-affinity site for noncompetitive blockers. The labeled ..beta.. chain was purified and digested with trypsin or CNBr, and the resulting fragments were fractionated by high-performance liquid chromatography. Sequence analysis resulted in the identification of Ser-254 and Leu-257 as residues labeled by (/sup 3/H)chlorpromazine in a phencyclidine-sensitive manner. These residues are located in the hydrophobic and potentially transmembrane segment M II of the ..beta.. chain, a region homologous to that containing the chlorpromazine-labeled Ser-262 in the delta chain. These results show that homologous regions of different receptor subunits contribute to the unique high-affinity site for noncompetitive blockers, a finding consistent with the location of this site on the axis of symmetry of the receptor molecule.

  7. Allosteric modulation of [3H]-CGP39653 binding through the glycine site of the NMDA receptor: further studies in rat and human brain

    PubMed Central

    Mugnaini, Manolo; Meoni, Paolo; Bunnemann, Bernd; Corsi, Mauro; Bowery, Norman G

    2001-01-01

    Binding of D,L-(E)-2-amino-4-[3H]-propyl-5-phosphono-3-pentenoic acid ([3H]-CGP39653), a selective antagonist at the glutamate site of the NMDA receptor, is modulated by glycine in rat brain tissue. We have further investigated this phenomenon in rodent and human brain by means of receptor binding and quantitative autoradiography techniques.In rat cerebral cortical membranes the glycine antagonist 3-[2-(Phenylaminocarbonyl)ethenyl]-4,6-dichloro-indole-2-carboxylic acid sodium salt (GV150526A) did not change basal [3H]-CGP39653 binding, but competitively reversed the high affinity component of [3H]-CGP39653 binding inhibition by glycine, with a pKB value of 8.38, in line with its affinity for the glycine site (pKi=8.49 vs [3H]-glycine). Glycine (10 μM) significantly decreased [3H]-CGP39653 affinity for the NMDA receptor (with no change in the Bmax), whereas enhanced L-glutamate affinity (P<0.05, paired-samples Student's t-test).In rat brain sections the addition of GV150526A (30 μM) to the incubation medium increased [3H]-CGP39653 binding to 208% of control (average between areas), indicating the presence of endogenous glycine. The enhancement presented significant regional differences (P<0.05, two-way ANOVA), with striatum higher than cerebral cortex (282 and 187% of control, respectively; P<0.05, Fisher's LSD). On the contrary, there was not any significant variation in affinity values of [3H]-CGP39653, L-glutamate, glycine and GV150526A in striatal and cortical membranes. These results confirmed the existence of regionally distinct NMDA receptors subtypes with different glycine/glutamate allosteric modulation.Whole brain autoradiography revealed an uneven distribution of [3H]-CGP39653 binding sites in human brain. High levels of binding were determined in hippocampus and in cingulate, frontoparietal and insular cortex. Intermediate to low levels of binding were found in diencephalic nuclei and basal ganglia. [3H]-CGP39653 binding was increased to 216% of

  8. Development of a radioligand, [(3)H]LY2119620, to probe the human M(2) and M(4) muscarinic receptor allosteric binding sites.

    PubMed

    Schober, Douglas A; Croy, Carrie H; Xiao, Hongling; Christopoulos, Arthur; Felder, Christian C

    2014-07-01

    In this study, we characterized a muscarinic acetylcholine receptor (mAChR) potentiator, LY2119620 (3-amino-5-chloro-N-cyclopropyl-4-methyl-6-[2-(4-methylpiperazin-1-yl)-2-oxoethoxy]thieno[2,3-b]pyridine-2-carboxamide) as a novel probe of the human M2 and M4 allosteric binding sites. Since the discovery of allosteric binding sites on G protein-coupled receptors, compounds targeting these novel sites have been starting to emerge. For example, LY2033298 (3-amino-5-chloro-6-methoxy-4-methyl-thieno(2,3-b)pyridine-2-carboxylic acid cyclopropylamid) and a derivative of this chemical scaffold, VU152100 (3-amino-N-(4-methoxybenzyl)-4,6-dim​ethylthieno[2,3-b]pyridine carboxamide), bind to the human M4 mAChR allosteric pocket. In the current study, we characterized LY2119620, a compound similar in structure to LY2033298 and binds to the same allosteric site on the human M4 mAChRs. However, LY2119620 also binds to an allosteric site on the human M2 subtype. [(3)H]NMS ([(3)H]N-methylscopolamine) binding experiments confirm that LY2119620 does not compete for the orthosteric binding pocket at any of the five muscarinic receptor subtypes. Dissociation kinetic studies using [(3)H]NMS further support that LY2119620 binds allosterically to the M2 and M4 mAChRs and was positively cooperative with muscarinic orthosteric agonists. To probe directly the allosteric sites on M2 and M4, we radiolabeled LY2119620. Cooperativity binding of [(3)H]LY2119620 with mAChR orthosteric agonists detects significant changes in Bmax values with little change in Kd, suggesting a G protein-dependent process. Furthermore, [(3)H]LY2119620 was displaced by compounds of similar chemical structure but not by previously described mAChR allosteric compounds such as gallamine or WIN 62,577 (17-β-hydroxy-17-α-ethynyl-δ-4-androstano[3,2-b]pyrimido[1,2-a]benzimidazole). Our results therefore demonstrate the development of a radioligand, [(3)H]LY2119620 to probe specifically the human M2 and M4 muscarinic

  9. Heterogeneity of nuclear estrogen-binding sites in the rat uterus: a simple method for the quantitation of type I and type II sites by (3H)estradiol exchange

    SciTech Connect

    Markaverich, B.M.; Williams, M.; Upchurch, S.; Clark, J.H.

    1981-07-01

    Estrogen administration to mature-ovariectomized rats causes the activation or stimulation of secondary nuclear estrogen-binding sites (type II) in the uterus which can interfere with estrogen receptor (type I) measurement. Earlier reports from our laboratory have shown that quantitation of type I sites in the presence of the type II site is very difficult and can only be achieved by graphic analysis of saturation curves which employ a wide range (0.4-40 NM) of (/sup 3/H)estradiol concentrations in nuclear exchange assay. The studies presented in this manuscript describe simple methods which can be used to separately quantitate both nuclear estrogen-binding sites using a single concentration of (/sup 3/H)estradiol. Since the nuclear type II site does not bind (/sup 3/H)estradiol in the presence of reducing agent, type I sites can be easily quantitated by incubating nuclei (37 C for 30 min) in Tris-EDTA buffer containing 0.1-1.00 mM dithiothreitol using a single saturating concentration of (/sup 3/H)estradiol. Conversely, a single concentration of (/sup 3/H)estradiol (40-80 nM) can be used to quantitate the nuclear type II site by incubating nuclei in Tris-EDTA buffer under conditions (4 C for 60 min) which do not measure occupied nuclear estrogen receptor. Therefore, by using the appropriate buffer system, type I and type II sites can be easily separated in mixed binding systems. In addition, we also demonstrate that Nafoxidine does not bind to the nuclear type II site. Therefore, it can be used as a competitive inhibitor of (/sup 3/H)estradiol binding to type I sites and permit the measurement of type II sites without interference from type I sites. These techniques should be applicable to autoradiographic or fluorescence studies which cannot discriminate between steroid binding to these two classes of nuclear estrogen-binding sites.

  10. Localization and characterization of (/sup 3/H)desmethylimipramine binding sites in rat brain by quantitative autoradiography

    SciTech Connect

    Biegon, A.; Rainbow, T.C.

    1983-05-01

    The high affinity binding sites for the antidepressant desmethlyimipramine (DMI) have been localized in rat brain by quantitative autoradiography. There are high concentrations of binding sites in the locus ceruleus, the anterior ventral thalamus, the ventral portion of the bed nucleus of the stria terminalis, the paraventricular and the dorsomedial nuclei of the hypothalamus. The distribution of DMI binding sites is in striking accord with the distribution of norepinephrine terminals. Pretreatment of rats with the neurotoxin 6-hydroxydopamine, which causes a selective degeneration of catecholamine terminals, results in 60 to 90% decrease in DMI binding. These data support the idea that high affinity binding sites for DMI are located on presynaptic noradrenergic terminals.

  11. The ACE inhibitor ( sup 3 H)SQ29,852 identifies a high affinity recognition site located in the human temporal cortex

    SciTech Connect

    Barnes, N.M.; Costall, B.; Egli, P.; Horovitz, Z.P.; Ironside, J.W.; Naylor, R.J.; Williams, T.J. )

    1990-07-01

    The angiotensin converting enzyme (ACE) inhibitor ({sup 3}H)SQ29,852 identified a single high affinity recognition site (defined by 10.0 microM captopril) in the human temporal cortex (pKD 8.62 +/- 0.03; Bmax 248 +/- 24 fmol mg-1 protein, mean +/- S.E.M., n = 4). ACE inhibitors and thiorphan competed to a similar level for the ({sup 3}H)SQ29,852 binding site in the human temporal cortex with a rank order of affinity (pKi values mean +/- S.E.M., n = 3), lisinopril (9.49 +/- 0.02), captopril (9.16 +/- 0.08), SQ29,852 (8.58 +/- 0.04), epicaptopril (7.09 +/- 0.08), fosinopril (7.08 +/- 0.05) and thiorphan (6.40 +/- 0.04). Since this rank order of affinity is similar to the affinity of these compounds to inhibit brain ACE activity it is concluded that ({sup 3}H)SQ29,852 selectively labels the inhibitor recognition site of ACE in the human temporal cortex.

  12. Use of site symmetry in supercell models of defective crystals: polarons in CeO2.

    PubMed

    Evarestov, R A; Gryaznov, D; Arrigoni, M; Kotomin, E A; Chesnokov, A; Maier, J

    2017-03-22

    In supercell calculations of defective crystals, it is common to place a point defect or vacancy in the atomic position with the highest possible point symmetry. Then, the initial atomic structure is often arbitrary distorted before its optimization, which searches for the total energy minimum. In this paper, we suggest an alternative approach to the application of supercell models and show that it is necessary to preliminarily analyze the site symmetry of the split Wyckoff positions of the perfect crystal supercell atoms (which will be substituted or removed in defective crystals) and then perform supercell calculations with point defects for different possible site symmetries, to find the energetically most favorable defect configuration, which does not necessarily correspond to the highest site symmetry. Using CeO2 as an example, it is demonstrated that this use of the site symmetry of the removed oxygen atoms in the supercells with vacancies allows us to obtain all the possible atomic and magnetic polaron configurations, and predict which vacancy positions correspond to the lowest formation energies associated with small polarons. We give a simple symmetry based explanation for the existence of controversies in the literature on the nature of the oxygen vacancies in CeO2. In particular, the experimentally observed small polaron formation could arise for oxygen vacancies with the lowest Cs site symmetry, which exist in 3 × 3 × 3 and larger supercells. The results of first principles calculations using a linear combination of atomic orbitals and hybrid exchange-correlation functionals are compared with those from previous studies, obtained using a widely used DFT+U approach.

  13. Characterization of the binding of [3H]-SB-204269, a radiolabelled form of the new anticonvulsant SB-204269, to a novel binding site in rat brain membranes

    PubMed Central

    Herdon, Hugh J; Jerman, Jeffrey C; Stean, Tania O; Middlemiss, Derek N; Chan, Wai N; Vong, Antonio K; Evans, John M; Thompson, Mervyn; Upton, Neil

    1997-01-01

    SB-204269 (trans-(+)-6-acetyl-4S-(4-fluorobenzoylamino)-3,4-dihydro-2,2-dimethyl-2H-benzol[b]pyran-3R-ol, hemihydrate) shows potent anticonvulsant activity in a range of animal seizure models, with a lack of neurological or cardiovascular side-effects. The profile of the compound suggests that it may have a novel mechanism of action. This study describes the characteristics of a binding site for [3H]-SB-204269 in rat forebrain membranes. Specific [3H]-SB-204269 binding was saturable and analysis indicated binding to a homogenoeous population of non-interacting binding sites with a dissociation constant (KD) of 32±1 nM and a maximum binding capacity (Bmax) of 253±18 fmol mg−1 protein. Kinetic studies indicated monophasic association and dissociation. Binding was similar in HEPES or Tris-HCl buffers and was unaffected by Na+, K+, Ca2+ or Mg2+ ions. Specific binding was widely distributed in brain, but was minimal in a range of peripheral tissues. Specific [3H]-SB-204269 binding was highly stereoselective, with a 1000 fold difference between the affinities of SB-204269 and its enantiomer SB-204268 for the binding site. The affinities of analogues of SB-204269 for binding can be related to their activities in the mouse maximal electroshock seizure threshold (MEST) test of anticonvulsant action. None of the standard anticonvulsant drugs, phenobarbitone, phenytoin, sodium valproate, carbamazepine, diazepam and ethosuximide, or the newer anticonvulsants, lamotrigine, vigabatrin, gabapentin and levetiracetam, showed any affinity for the [3H]-SB-204269 binding site. A wide range of drugs active at amino acid receptors, Na+ or K+ channels or various other receptors did not demonstrate any affinity for the binding site. These studies indicate that SB-204269 possesses a specific CNS binding site which may mediate its anticonvulsant activity. This binding site does not appear to be directly related to the sites of action of other known anticonvulsant agents, but may

  14. Omega 3 (peripheral type benzodiazepine binding) site distribution in the rat immune system: an autoradiographic study with the photoaffinity ligand (/sup 3/H)PK 14105

    SciTech Connect

    Benavides, J.; Dubois, A.; Dennis, T.; Hamel, E.; Scatton, B.

    1989-04-01

    The anatomical distribution of omega 3 (peripheral type benzodiazepine binding) sites in the immune system organs of the rat has been studied autoradiographically at both macroscopic and microscopic levels of resolution using either reversible or irreversible (UV irradiation) labeling with (/sup 3/H)PK 14105. In thymus sections, (/sup 3/H)PK 14105 labeled with high affinity (Kd, derived from saturation experiments = 10.8 nM) a single population of sites which possessed the pharmacological characteristics of omega 3 sites. In the thymus gland, higher omega 3 site densities were detected in the cortex than in the medulla; in these subregions, silver grains were associated to small (10-18 microns diameter) cells. In the spleen, omega 3 sites were more abundant in the white than in the red pulp. In the white pulp, silver grains were denser in the marginal zone than in the vicinity of the central artery and labeling was, as in the thymus, associated to small cytoplasm-poor cells. In the red pulp, omega 3 site associated silver grains were observed mainly in the Bilroth cords. In the lymph nodes, the medullary region showed a higher labeling than the surrounding follicles and paracortex. A significant accumulation of silver grains was observed in the lymph node medullary cords. In the intestine, Peyer patches were particularly enriched in omega 3 sites (especially in the periphery of the follicles). The distribution of omega 3 sites in the immune system organs suggests a preferential labeling of cells of T and monocytic lineages. This is consistent with the proposed immunoregulatory properties of some omega 3 site ligands.

  15. Uniaxial stress induced symmetry breaking for muon sites in Fe

    NASA Technical Reports Server (NTRS)

    Kossler, W. J.; Namkung, M.; Hitti, B.; Li, Y.; Kempton, J.; Stronach, C. E.; Goode, L. R., Jr.; Lankford, W. F.; Patterson, B. D.; Kuendig, W.

    1984-01-01

    Uniaxial stress was used on Fe single crystals to induce muon precession frequency shifts. The frequency shift for a nominally pure Fe sample at 302K was -0.34 + or - .023 MHz per 100 microstrain along the 100 magnetization axis. This corresponds to a change of magnetic field at the muon of 25.1 + to 1.6G/100 magnetic moment. For an Fe (3wt%Si) single crystal the shifts were -0.348 + or - .008 MHz/100 magnetic moment. The agreement between the shifts for Fe and Fe(3wt%Si) shows the effect to be intrinsic to iron and not strongly impurity sensitive. These shifts and their temperature dependence (1/T) are dominated by the effect of strain inducted population shifts between crystallographically equivalent, but mgnetically inequivalent sites. Their magnitudes are in good agreement ith previous theoretical predictions and by previous extrapolation from calculations on Nb and V especially if both 4T(0) and 1T sites contribute comparably.

  16. GABAA receptor sites modulating catecholamine secretion in the rat adrenal gland: evidence from 3H-muscimol autoradiography and in vivo functional studies.

    PubMed

    Amenta, F; Collier, W L; Erdö, S L; Giuliani, S; Maggi, C A; Meli, A

    1988-01-01

    The occurrence and distribution of specific 3H-muscimol binding sites, most probably identical with A type gamma-aminobutyric acid (GABA) receptors, were studied in sections of the rat adrenal gland by light microscope autoradiography. Specific binding was found primarily in the adrenal medulla, in association with chromaffin cells. A limited number of binding sites was also observed within the adrenal cortex. In urethane-anaesthetized hexamethonium-pretreated rats, intravenous GABA produced a set of 'excitatory' cardiovascular effects (increase in heart rate, force of contraction and blood pressure) which were mimicked by intravenous muscimol but not by intravenous baclofen, and were antagonized by pretreatment with bicuculline. The cardiovascular excitatory effects of intravenous GABA were unaffected by reserpine pretreatment, markedly reduced by administration of phentolamine plus propranolol, and almost completely abolished by adrenalectomy. Our findings indicate the presence of GABA receptor sites on adrenal chromaffin cells, whose excitation can produce changes in cardiovascular function.

  17. Binding of L-(/sup 3/H)nicotine to a single class of high affinity sites in rat brain membranes

    SciTech Connect

    Lippiello, P.M.; Fernandes, K.G.

    1986-05-01

    The binding of optically pure L-(/sup 3/H)nicotine to rat brain membrane preparations was studied using a rapid filtration method. The binding properties observed depended on the method used for tissue isolation. The most consistent results were obtained with membranes prepared in the presence of protease inhibitors, without divalent cations. Binding was saturable, reversible, and stereospecific. Scatchard analysis revealed a single class of high affinity sites with an average KD of 2 nM and a Bmax of approximately 200 fmol/mg of protein. The Hill coefficient was near unity. The KD calculated from the kinetic rate constants for association (k1 = 0.012 min-1 nM-1) and dissociation (k-1 = 0.04 min-1) was around 3 nM, in good agreement with the dissociation constant determined from equilibrium binding. In competition studies, cholinergic agonists were generally the most effective in inhibiting L-(/sup 3/H)nicotine binding, whereas antagonists were relatively ineffective. The D-isomer of nicotine was about 60-fold less potent than the L-isomer in inhibiting binding. The results were unaffected by temperature, with the exception that Bmax was somewhat lower at 37 degrees. The equilibrium binding properties of these sites were essentially identical in adult male and female brain. However, Bmax was lower in fetal brain tissue. The present findings are consistent with the idea that there is a single class of high affinity nicotinic binding sites in rat brain with cholinoceptive properties.

  18. [3H]-Mesulergine labels 5-HT7 sites in rat brain and guinea-pig ileum but not rat jejunum

    PubMed Central

    Hemedah, Maggie; Coupar, Ian M; Mitchelson, Fred J

    1999-01-01

    The primary aim of this investigation was to determine whether binding sites corresponding to the 5-HT7 receptor could be detected in smooth muscle of the rat jejunum. Binding studies in rat brain (whole brain minus cerebellum) and guinea-pig ileal longitudinal muscle were also undertaken in order to compare the binding characteristics of these tissues. Studies were performed using [3H]-mesulergine, as it has a high affinity for 5-HT7 receptors.In the rat brain and guinea-pig ileum, pKD values for [3H]-mesulergine of 8.0±0.04 and 7.9±0.11 (n=3) and Bmax values of 9.9±0.3 and 21.5±4.9 fmol mg−1 protein were obtained respectively, but no binding was detected in the rat jejunum. [3H]-mesulergine binding in the rat brain and guinea-pig ileum was displaced with the agonists 5-carboxamidotryptamine (5-CT)>5-hydroxytryptamine (5-HT)⩾5-methoxytryptamine (5-MeOT)>sumatriptan and the antagonists risperidone⩾LSD⩾metergoline>ritanserin>>pindolol.Despite the lack of [3H]-mesulergine binding in the rat jejunum, functional studies undertaken revealed a biphasic contractile response to 5-HT which was partly blocked by ondansetron (1 μM). The residual response was present in over 50% of tissues studied and was found to be inhibited by risperidone>LSD>metergoline>mesulergine=ritanserin>pindolol, but was unaffected by RS 102221 (3 μM), cinanserin (30 nM), yohimbine (0.1 μM) and GR 113808 (1 μM). In addition, the agonist order of potency was 5-CT>5-HT>5-MeOT>sumatriptan.In conclusion, binding studies performed with [3H]-mesulergine were able to detect 5-HT7 sites in rat brain and guinea-pig ileum, but not in rat jejunum, where a functional 5-HT7-like receptor was present. PMID:10051134

  19. Chronic treatment with the monoamine oxidase inhibitors clorgyline and pargyline down-regulates non-adrenoceptor [3H]-idazoxan binding sites in the rat brain.

    PubMed Central

    Olmos, G.; Gabilondo, A. M.; Miralles, A.; Escriba, P. V.; García-Sevilla, J. A.

    1993-01-01

    1. The binding of [3H]-idazoxan in the presence of 10(-6) M (-)-adrenaline was used to quantitate non-adrenoceptor idazoxan binding sites (NAIBS) in the rat brain after treatment with various psychotropic drugs. 2. Chronic treatment (14 days) with the monoamine oxidase (MAO) inhibitors clorgyline (0.3-10 mg kg-1, i.p.) and pargyline (10 mg kg-1, i.p.), but not with Ro 41-1049 (1 mg kg-1, i.p.), markedly decreased (30-50%) the density of NAIBS in the cerebral cortex without any apparent change in the affinity of the radioligand. 3. Acute (1 day) and/or chronic treatments (14 days) with other psychotropic drugs such as desipramine (3 mg kg-1, i.p.), cocaine (10 mg kg-1, i.p.), reserpine (0.12 mg kg-1, s.c.), haloperidol (1 mg kg-1, i.p.) and diazepam (10 mg kg-1, i.p.) did not alter the density of NAIBS in the cerebral cortex. 4. In vitro, the propargylamines clorgyline, pargyline and deprenyl displaced the binding of [3H]-idazoxan to NAIBS from two distinct sites, but only clorgyline displayed an apparent very high affinity for a relevant population of NAIBS (KiH = 40 pM; KiL = 10.6 microM). The structurally diverse MAO inhibitors Ro 16-6491 (selective for MAO-B) and Ro 41-1049 (selective for MAO-A), as well as the other psychotropic drugs (desipramine, cocaine, reserpine and haloperidol) displaced the binding of [3H]-idazoxan to NAIBS monophasically and with very low potencies.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:8385528

  20. (/sup 3/H)-ouabain binding sites and (Na/sup +/ + K/sup +/)ATPase activity in heart of rats fed cholesterol

    SciTech Connect

    Ren, Y.F.; Alam, B.S.; Alam, S.Q.

    1986-03-05

    The purpose of this investigation was to determine the effects of cholesterol on the characteristics of ouabain binding sites and (Na/sup +/ + K/sup +/)ATPase activity in heart. Three groups of male, weanling, Sprague-Dawley rats were fed for 5 weeks diets containing 0, 1 or 2% cholesterol. Membranes were prepared from deoxycholate-treated heart homogenates by differential centrifugation and assayed for ouabain binding and (Na/sup +/ + K/sup +/)ATPase activity. Membranes were incubated with (/sup 3/H)-ouabain in the presence of 10 mM Tris-HCl buffer (pH 7.4) and rapidly filtered on glass fiber filters, GF/A. Non-specific binding was measured in the presence of 6 mM non-labeled ouabain. Concentration of (/sup 3/H)-ouabain binding sites (B/sub max/) was decreased and the binding affinity was increased in the membranes of rats fed 2% cholesterol. The ouabain-sensitive (Na/sup +/ + K/sup +/)ATPase activity was 50-75% lower in membranes prepared from heart of rats fed cholesterol. The Mg/sup 2 +/-ATPase activity was not changed by dietary cholesterol. The results suggest that cholesterol feeding decreases the number of (Na/sup +/ + K/sup +/)ATPase units and allosterically modifies the enzyme.

  1. Guanyl nucleotide interactions with dopaminergic binding sites labeled by (/sup 3/H)spiroperidol in human caudate and putamen: guanyl nucleotides enhance ascorbate-induced lipid peroxidation and cause an apparent loss of high affinity binding sites

    SciTech Connect

    Andorn, A.C.; Bacon, B.R.; Nguyen-Hunh, A.T.; Parlato, S.J.; Stitts, J.A.

    1988-02-01

    The human caudate and putamen contain two high affinity binding sites for (/sup 3/H)spiroperidol. Both of these affinity states exhibit dopaminergic selectivity. Ascorbic acid, at 0.1 mM, induces a slow loss of the low affinity component of (/sup 3/H)spiroperidol binding in these tissues. The addition of guanyl nucleotides to the ascorbate produces a more rapid loss of (/sup 3/H)spiroperidol binding which includes a loss of the highest affinity state for (/sup 3/H)spiroperidol. Ascorbate induces lipid peroxidation in human caudate and putamen, an effect that is further enhanced by guanyl and inosine nucleotides. In the absence of ascorbate, guanyl nucleotides have no effect on (/sup 3/H)spiroperidol binding but do decrease the affinity of dopamine at each affinity state greater than 60-fold. In the absence of ascorbate, guanyl nucleotides apparently decrease agonist affinity at human brain dopamine2-binding sites without causing an interconversion of agonist affinity states.

  2. A design study for the isolation of the 281-3H retention basin at the Savannah River Site using the viscous liquid barrier technology

    SciTech Connect

    Moridis, G.J.; Persoff, P.; Apps, J.; James, A.; Oldenburg, C.; McGrath, A.; Myer, L.; Pellerin, L.; Pruess, K.

    1996-11-01

    This report is a description of the design study for a pilot-scale field demonstration of the Viscous Liquid Barrier (VLB) technology, a new subsurface containment technology for waste isolation using a new generation of barrier liquids. The demonstration site was Retention Basin 281-3H, a shallow catchment basin at the Savannah River Site, which is contaminated mainly by radionuclides ({sup 137}Cs, {sup 90}Sr, and {sup 238}Pu). The goals of the field demonstration were (a) to demonstrate the ability to create a continuous subsurface barrier in order to isolate the contaminants, and (b) to demonstrate the continuity, performance, and integrity of the barrier. The site was characterized, and preliminary hydraulic conductivity data were obtained from core samples. Based on the site characteristics and the functional requirements, a conceptual model was developed, the barrier specifications were defined, and lance injection was selected as the emplacement method. The injection strategy for the subsurface conditions at the site was determined using numerical simulations. An appropriate variant of Colloidal Silica (CS) was selected as the barrier liquid based on its relative insensitivity to interactions with the site soils, and the formulation for optimum site performance was determined. A barrier verification strategy, including hydraulic, pneumatic, tracer, and geophysical methods, was developed. A lance water injection test was conducted in order to obtain representative estimates of the hydraulic conductivity and its distribution for the design of the barrier emplacement. The water injection test demonstrated the lack of permeable zones for CS injection, and a decision not to proceed with the barrier emplacement was reached.

  3. Immobilization of Ag(i) into a metal-organic framework with -SO3H sites for highly selective olefin-paraffin separation at room temperature.

    PubMed

    Chang, Ganggang; Huang, Minhui; Su, Ye; Xing, Huabin; Su, Baogen; Zhang, Zhiguo; Yang, Qiwei; Yang, Yiwen; Ren, Qilong; Bao, Zongbi; Chen, Banglin

    2015-02-18

    Introduction of Ag(i) ions into a sulfonic acid functionalized MOF ((Cr)-MIL-101-SO3H) significantly enhances its interactions with olefin double bonds, leading to its much higher selectivities for the separation of C2H4-C2H6 and C3H6-C3H8 at room temperature over the original (Cr)-MIL-101-SO3H and other adsorbents at room temperature.

  4. [(3) H]-L685,458 binding sites are abundant in multiple peripheral organs in rats: implications for safety assessment of putative γ-secretase targeting drugs.

    PubMed

    Yang, Zhi-Ying; Li, Jian-Ming; Xiao, Ling; Mou, Lin; Cai, Yan; Huang, He; Luo, Xue-Gang; Yan, Xiao-Xin

    2014-12-01

    γ-Secretase is a multimeric enzyme complex that carries out proteolytic processing to a variety of cellular proteins. It is currently explored as a therapeutic target for Alzheimer's disease (AD) and cancer. Mechanism-based toxicity needs to be thoroughly evaluated for γ-secretase inhibitory and/or modulatory drugs. This study comparatively assessed putative γ-secretase catalytic sites in rat peripheral tissues relative to brain and explored an effort of its pharmacological inhibition on hair regeneration. Using [(3) H]-labelled L685,458, a potent γ-secretase inhibitor, as probe, we found more abundant presence of γ-secretase binding sites in the liver, gastrointestinal tract, hair follicle, pituitary gland, ovary and testis, as compared to the brain. Local application of L658,458 delayed vibrissal regrowth following whisker removal. These results suggest that γ-secretase may execute important biological functions in many peripheral systems, as in the brain. The development of γ-secretase inhibitors/modulators for AD and cancer therapy should include close monitoring of toxicological panels for hepatic, gastrointestinal, endocrinal and reproductive functions.

  5. Local Ordering at Mobile Sites in Proteins from Nuclear Magnetic Resonance Relaxation: The Role of Site Symmetry.

    PubMed

    Tchaicheeyan, Oren; Freed, Jack H; Meirovitch, Eva

    2016-03-24

    Restricted motions in proteins (e.g., N-H bond dynamics) are studied effectively with NMR. By analogy with restricted motions in liquid crystals (LC), the local ordering has in the past been primarily represented by potentials comprising the L = 2, |K| = 0, 2 spherical harmonics. However, probes dissolved in LCs experience nonpolar ordering, often referred to as alignment, while protein-anchored probes experience polar ordering, often referred to as orientation. In this study we investigate the role of local (site) symmetry in the context of the polarity of the local ordering. We find that potentials comprising the L = 1, |K| = 0, 1 spherical harmonics represent adequately polar ordering. It is useful to characterize potential symmetry in terms of the irreducible representations of D2h point group, which is already implicit in the definition of the rotational diffusion tensor. Thus, the relevant rhombic L = 1 potentials have B1u and B3u symmetry whereas the relevant rhombic L = 2 potentials have Ag symmetry. A comprehensive scheme where local potentials and corresponding probability density functions (PDFs) are represented in Cartesian and spherical coordinates clarifies how they are affected by polar and nonpolar ordering. The Cartesian coordinates are chosen so that the principal axis of polar axial PDF is pointing along the z-axis, whereas the principal axis of the nonpolar axial PDF is pointing along ±z. Two-term axial potentials with 1 ≤ L ≤ 3 exhibit substantial diversity; they are expected to be useful in NMR-relaxation-data-fitting. It is shown how potential coefficients are reflected in the experimental order parameters. The comprehensive scheme representing local potentials and PDFs is exemplified for the L = 2 case using experimental data from (15)N-labeled plexin-B1 and thioredoxin, (2)H-, and (13)C-labeled benzenehexa-n-alkanoates, and nitroxide-labeled T4 lysozyme. Future prospects for improved ordering analysis based on combined atomistic and

  6. The chronic infusion of nicotine into the developing chick embryo does not alter the density of (-)-[3H]nicotine-binding sites or vestibular function

    NASA Technical Reports Server (NTRS)

    Roll, R. L.; Jones, T. A.; Benowitz, N. L.; Morley, B. J.

    1993-01-01

    (-)-Nicotine (1.2 mg/day) or saline was infused into chick embryos (Gallus domesticus) for 10 days beginning 12 h beyond the eight day of incubation (E8 + 12 h). Twelve h beyond the eighteenth day of incubation (E18 + 12 h), the eggs were opened to access the embryos and subcutaneous skull electrodes placed. Short latency vestibular response thresholds and input/output functions were determined to assess neurophysiological consequences of chronic nicotine administration. Samples of serum and extraembryonic (amniotic and albumen) fluid were analyzed by gas chromatography-mass spectrometry to determine the levels of nicotine and its major metabolite, cotinine. The brains were removed and divided into diencephalon and mesencephalon and the density of (-)-[3H]nicotine binding sites in each brain area was measured. Nicotine and cotinine were found in the serum and extraembryonic fluid, but nicotinic receptors were not up-regulated in the brains of animals infused with nicotine in comparison to controls. Vestibular response thresholds also did not differ between nicotine-treated and control animals.

  7. Existence of a low-affinity ATP-binding site in the unphosphorylated Ca2(+)-ATPase of sarcoplasmic reticulum vesicles: evidence from binding of 2',3'-O-(2,4,6-trinitrocyclohexadienylidene)-[3H]AMP and -[3H]ATP.

    PubMed

    Suzuki, H; Kubota, T; Kubo, K; Kanazawa, T

    1990-07-31

    ATP-binding sites in the unphosphorylated Ca2(+)-ATPase of sarcoplasmic reticulum vesicles were titrated with 2',3'-O-(2,4,6-trinitrocyclohexadienylidene)-[3H]AMP (TNP-AMP) or -[3H]ATP (TNP-ATP) in the absence of Ca2+ at pH 7.0 and 0 degrees C by using a centrifugation procedure. In some measurements, the bound TNP-nucleotides were chased with ATP. The data were analyzed by best-fit computer programs as well as by Scatchard plots. The results showed the existence of 1 mol of TNP-AMP binding sites with high affinity (Kd = 7.62 nM) per mole of phosphorylatable sites. The affinity of these sites for ATP (Kd = 10.1 microM) agreed with that of catalytic sites for ATP in the absence of Ca2+. The results further showed the existence of 2 mol of TNP-ATP binding sites with uniform affinity (Kd = 156 nM) per mole of phosphorylatable sites. Half of the bound TNP-ATP was fully chased by low concentrations of ATP. The affinity of this class of the sites for ATP (Kd = 8.9 microM) again agreed with that of catalytic sites for ATP. The other half of the bound TNP-ATP was fully chased only by much higher concentrations of ATP. Thus, the affinity of this class of the sites for ATP (Kd = 791 microM) was much lower than that of catalytic sites for ATP. Similar measurements were performed with sarcoplasmic reticulum vesicles pretreated by N-(iodoacetyl)-N'-(5-sulfo-1-naphthyl)ethylenediamine. Although the affinities for TNP-ATP and for ATP were appreciably altered by this pretreatment, the results were essentially the same as those obtained with native vesicles.(ABSTRACT TRUNCATED AT 250 WORDS)

  8. Changes in the affinity of (/sup 3/H)nimodipine binding sites in the brain upon chlorpromazine treatment and subsequent withdrawal

    SciTech Connect

    Ramkumar, V.; el-Fakahany, E.E.

    1985-06-01

    Male mice were chronically treated with chlorpromazine mixed in powdered diet, and the properties of brain calcium channels were assessed using (/sup 3/H)nimodipine binding. It was found that this treatment resulted in a significant increase in the affinity of calcium channels, without a significant change in their density. These effects of chlorpromazine were time dependent. When mice were administered chlorpromazine for 2 months, then the drug was withdrawn, there was a rebound decrease in the channel affinity.

  9. Identification of symmetry, structure and defects of dopant Mn(II) ions in Zn(C 3H 3O 4) 2(H 2O) 2 by single crystal EPR technique

    NASA Astrophysics Data System (ADS)

    Natarajan, B.; Mithira, S.; Sambasiva Rao, P.

    2008-12-01

    In order to understand the symmetry, structure and defects of Mn(II) impurity incorporated in diaquabis[malonato(1-)-κ 2O,O'] zinc(II), single crystal EPR studies have been carried out at X-band frequencies at room temperature. Angular variation in the three orthogonal planes shows the presence of two defects, having a relatively large and small zero-field splitting parameter ( D), with orthorhombic symmetry. The spin-Hamiltonian parameters, estimated from the three mutually orthogonal crystal rotations, are: Defect I:g xx = 1.959, g yy = 1.998, g zz = 2.011; A xx = -8.73, A yy = -8.55, A zz = -9.10 mT; D xx = 5.58, D yy = 1.33, D zz = -6.91 mT. Defect II:g xx = 2.015, g yy = 1.996, g zz = 2.004; A xx = -8.18, A yy = -8.00, A zz = -8.58 mT; D xx = 33.48, D yy = 6.92, D zz = -40.40 mT. The observed large zero-field tensor for Defect II is due to the steric effects caused by the two malonate rings. The location of the two interstitial defects has been determined from the X-ray data of the host lattice. The powder EPR spectrum also confirms the chemical inequivalence of the two defects. The optical absorption spectrum shows the characteristic of Mn(II) ions in distorted octahedral symmetry.

  10. Affinities and densities of high-affinity (/sup 3/H)muscimol (GABA-A) binding sites and of central benzodiazepine receptors are unchanged in autopsied brain tissue from cirrhotic patients with hepatic encephalopathy

    SciTech Connect

    Butterworth, R.F.; Lavoie, J.; Giguere, J.F.; Pomier-Layrargues, G.

    1988-09-01

    The integrity of GABA-A receptors and of central benzodiazepine receptors was evaluated in membrane preparations from prefrontal cortex and caudate nuclei obtained at autopsy from nine cirrhotic patients who died in hepatic coma and an equal number of age-matched control subjects. Histopathological studies revealed Alzheimer Type II astrocytosis in all cases in the cirrhotic group; controls were free from neurological, psychiatric or hepatic diseases. Binding to GABA-A receptors was studied using (/sup 3/H)muscimol as radioligand. The integrity of central benzodiazepine receptors was evaluated using (/sup 3/H)flunitrazepam and (/sup 3/H)Ro15-1788. Data from saturation binding assays was analyzed by Scatchard plot. No modifications of either affinities (Kd) or densities (Bmax) of (/sup 3/H)muscimol of central benzodiazepine binding sites were observed. These findings do not support recent suggestions that alterations of either high-affinity GABA or benzodiazepine receptors play a significant role in the pathogenesis of hepatic encephalopathy.

  11. Guest dynamics in solid acetone-d/sub 6/-DOCA and acetone-d/sub 6/-APA inclusion compounds: correlation between the symmetry of the motion and the site symmetry. [Deoxycholic acid; Apocholic acid

    SciTech Connect

    Meirovitch, E.

    1986-10-23

    The molecular motion of acetone-d/sub 6/ acting as guest in deoxycholic acid and apocholic acid host lattices in the solid state is interpreted in light of a broader concept assessing that very often the motion of the guest proceeds through discrete jumps rather than diffusively and its symmetry is congenial with the site symmetry of the host lattice. In particular, the acetone molecules are engaged in threefold jumps about a unique axis, compatible with the 32 site symmetry of the host lattice. The entire dynamic range of this process is investigated in terms of spectral consequences brought about by variations in jump rates, in the relative population of the three symmetry related sites, and in instrumental parameters such as the time interval between the two 90/sup 0/ pulses in the quadrupole echo sequence and the length of the 90/sup 0/ pulses.

  12. Adrenergic receptor and catecholamine distribution in rat cerebral cortex: binding studies with [3H]prazosin, [3H]idazoxan and [3H]dihydroalprenolol.

    PubMed

    Diop, L; Brière, R; Grondin, L; Reader, T A

    1987-02-03

    The tritiated adrenergic antagonists [3H]dihydroalprenolol ([3H]DHA; beta-receptors), [3H]prazosin ([3H]PRZ; alpha 1-receptors), and [3H]idazoxan ([3H]IDA; alpha 2-receptors) were used to determine the distribution of these sites in 5 defined areas of the adult rat cerebral cortex. The highest density of [3H]PRZ binding was found in the prefrontal cortex, with a lower and homogeneous distribution for the frontal, parietal, occipital and temporal areas. The [3H]IDA binding sites were fairly uniform for all areas, except for the temporal cortex where it was very dense. In contrast, beta-adrenoceptors labelled by [3H]DHA were very homogeneous for all the regions examined. The functional significance of the distribution of alpha 1, alpha 2 and beta-adrenoceptors is discussed in relation to the catecholamine innervation and monoamine contents measured by high performance liquid chromatography.

  13. 3,4-Methylenedioxymethamphetamine and 3,4-methylenedioxyamphetamine destroy serotonin terminals in rat brain: quantification of neurodegeneration by measurement of (/sup 3/H)paroxetine-labeled serotonin uptake sites

    SciTech Connect

    Battaglia, G.; Yeh, S.Y.; O'Hearn, E.; Molliver, M.E.; Kuhar, M.J.; De Souza, E.B.

    1987-09-01

    This study examines the effects of repeated systemic administration (20 mg/kg s.c., twice daily for 4 days) of 3,4-methylenedioxymethamphetamine (MDMA) and 3,4-methylenedioxyamphetamine (MDA) on levels of brain monoamines, their metabolites and on the density of monoamine uptake sites in various regions of rat brain. Marked reductions (30-60%) in the concentration of 5-hydroxyindoleacetic acid were observed in cerebral cortex, hippocampus, striatum, hypothalamus and midbrain at 2 weeks after a 4-day treatment regimen of MDMA or MDA; less consistent reductions in serotonin (5-HT) content were observed in these brain regions. In addition, both MDMA and MDA caused comparable and substantial reductions (50-75%) in the density of (/sup 3/H)paroxetine-labeled 5-HT uptake sites in all brain regions examined. In contrast, neither MDMA nor MDA caused any widespread or long-term changes in the content of the catecholaminergic markers (i.e., norepinephrine, dopamine, 3,4 dihydroxyphenylacetic acid and homovanillic acid) or in the number of (/sup 3/H)mazindol-labeled norepinephrine or dopamine uptake sites in the brain regions examined. These data demonstrate that MDMA and MDA cause long-lasting neurotoxic effects with respect to both the functional and structural integrity of serotonergic neurons in brain. Furthermore, our measurement of reductions in the density of 5-HT uptake sites provides a means for quantification of the neurodegenerative effects of MDMA and MDA on presynaptic 5-HT terminals.

  14. Characterizing gapped phases of a 1D spin chain with on-site and spatial symmetries

    NASA Astrophysics Data System (ADS)

    West, Colin; Prakash, Abhishodh; Wei, Tzu-Chieh

    We investigate the phase diagram of a spin-1 chain whose Hamiltonian is invariant under translation, lattice inversion and a global A4 symmetry in the spin degrees of freedom. The classification scheme by Chen, Gu, and Wen allows us to enumerate all possible phases under the given symmetry. Then, we determine which of these phases actually occur in the two-parameter Hamiltonian. Using numerical methods proposed by Pollmann and Turner (2012) we determine the characteristic projective parameters for the Symmetry Protected Topological (SPT) phases. In addition, we present a method for determining the projective commutation parameter in these phases. The resulting phase diagram is rich and contains at least nine different SPT phases. This work was supported in part by the National Science Foundation.

  15. Interaction of pyracetam with specific /sup 3/H-imipramine binding sites and GABA-benzodiazepine receptor complex of brain membranes

    SciTech Connect

    Rozhanets, V.V.; Chakhbra, K.K.; Danchev, N.D.; Malin, K.M.; Rusakov, D.Yu.; Val'dman, A.V.

    1986-06-01

    This paper studies the effect of pyracetam on parameters of specific binding of tritium-imipramine and GABA-activated binding of tritium-flunitrazepam with rat brain membranes. The experimental method is described and it is shown that pyracetam and mebicar in experiments in vivo on normal animals can exert their anxiolytic action without the participation of bensodiazepine receptors. Either the interaction of pyracetam and mebicar with benzodiazeprine receptors has a different interpretation than competition of these compounds with specific binding sites of tritium-flunitrazepam, or in experiments on normal animals in vivo GABA-benzodiazepine receptor complex does not accept pyracetam and mebicar, for it contains endogenous inhibitors of GABA-modulating action.

  16. Site specific mutation of the Zic2 locus by microinjection of TALEN mRNA in mouse CD1, C3H and C57BL/6J oocytes.

    PubMed

    Davies, Benjamin; Davies, Graham; Preece, Christopher; Puliyadi, Rathi; Szumska, Dorota; Bhattacharya, Shoumo

    2013-01-01

    Transcription Activator-Like Effector Nucleases (TALENs) consist of a nuclease domain fused to a DNA binding domain which is engineered to bind to any genomic sequence. These chimeric enzymes can be used to introduce a double strand break at a specific genomic site which then can become the substrate for error-prone non-homologous end joining (NHEJ), generating mutations at the site of cleavage. In this report we investigate the feasibility of achieving targeted mutagenesis by microinjection of TALEN mRNA within the mouse oocyte. We achieved high rates of mutagenesis of the mouse Zic2 gene in all backgrounds examined including outbred CD1 and inbred C3H and C57BL/6J. Founder mutant Zic2 mice (eight independent alleles, with frameshift and deletion mutations) were created in C3H and C57BL/6J backgrounds. These mice transmitted the mutant alleles to the progeny with 100% efficiency, allowing the creation of inbred lines. Mutant mice display a curly tail phenotype consistent with Zic2 loss-of-function. The efficiency of site-specific germline mutation in the mouse confirm TALEN mediated mutagenesis in the oocyte to be a viable alternative to conventional gene targeting in embryonic stem cells where simple loss-of-function alleles are required. This technology enables allelic series of mutations to be generated quickly and efficiently in diverse genetic backgrounds and will be a valuable approach to rapidly create mutations in mice already bearing one or more mutant alleles at other genetic loci without the need for lengthy backcrossing.

  17. Quantitative analysis of the high-affinity binding sites for [3H]ouabain in the rat vas deferens and their immunological identification as the alpha 2 isoform of Na+/K(+)-ATPase.

    PubMed

    Noël, F; Quintas, L E; Freitas, E; Caricati-Neto, A; Lafayette, S S; Wanderley, A G; Jurkiewicz, A

    1998-05-01

    Binding assays were performed with [3H]ouabain to investigate the presence of, and to characterize, a Na+/K(+)-ATPase isoform with high affinity for cardiac glycosides in the rat vas deferens. Nonlinear regression analysis of equilibrium experiments carried out with crude preparations in a Mg-Pi medium indicated the presence of high-affinity sites characterized with good precision (individual coefficients of variation = 11-35%) by their density (Bmax = 0.42 to 0.72 pmol/mg protein) and dissociation constant (Kd = 0.069 to 0.136 microM) values. The values of the dissociation rate constant (kappa-1) and the association rate constant (kappa+1) for these sites were 0.151 to 0.267 min-1 and 2.87 to 3.60 microM-1.min-1, respectively. A higher number of low-affinity sites (Kd around 15 microM), supposed to correspond to the alpha 1 isoform, was also identified, but their Kd and Bmax values were not quantified precisely in this crude preparation. Western blot assays indicated hybridization with specific anti-alpha 1 and anti-alpha 2 isoform antibodies but not with anti-alpha 3 isoform antibody. Taken together, the present results indicate the existence of a low proportion of the alpha 2 isoform of Na+/K(+)-ATPase in the rat vas deferens that can be quantified precisely by [3H]ouabain binding even in a crude membrane preparation that is suitable for studies under conditions of plasticity.

  18. (/sup 3/H)leukotriene B/sub 4/ binding to the guinea pig spleen membranes: a rich tissue source for a high affinity leukotriene B/sub 4/ receptor site

    SciTech Connect

    Cheng, J.B.; Kohi, F.; Townley, R.G.

    1986-03-05

    To select a tissue rich for the high affinity leukotriene (LT)B/sub 4/ receptor site, they compared binding of 1 nM (/sup 3/H)LTB/sub 4/ (180 Ci/mmol) to the crude membrane preparations of guinea pig spleen, thymus, lung, uterus, bladder, brain, adrenal gland, small intestine, liver, kidney and heart. They found that the membrane preparations from spleen contained the highest binding activity per mg protein. They characterized the LTB/sub 4/ binding to the spleen preparation in detail. LTB/sub 4/ binding was rapid, reversible, stereoselective and saturable. The data from equilibrium experiments showed a linear Scatchard plot with a K/sub d/ of 1.6 nM and a binding site density of 259 fmol/mg prot. The rank order of agents competing for spleen (/sup 3/H)LTB/sub 4/ binding at 25/sup 0/C was: LTB/sub 4/ (K/sub i/ = 2.8 nM) > 20-OH-LTB/sub 4/ (23 nM) > LTA/sub 4/ (48 nM) > LTA/sub 4/ methyl ester (0.13 ..mu..M) > 20-COOH-LTB/sub 4/ (> 6.6 ..mu..M) greater than or equal to arachidonic acid (0.15 mM) similarly ordered FPL-55,712 (0.11 mM). At 4/sup 0/C, LTB/sub 4/ (2.3 nM) competed at least 10x more effectively than 20-OH-LTB/sub 4/ (29 nM) and 20-COOH-LTB/sub 4/ (> 6.6 ..mu..M). HPLC analysis indicated that incubation of 84 ng LTB/sub 4/ with the spleen membrane at 25/sup 0/C did not result in the formation of 20-OH-LTB/sub 4/ (< 1 ng) in the filtrate. They conclude that guinea pig spleen contains a rich tissue source of high affinity (/sup 3/H)LTB/sub 4/ receptor binding sites.

  19. Characterization of [35S]-ATP alpha S and [3H]-alpha, beta-MeATP binding sites in rat brain cortical synaptosomes: regulation of ligand binding by divalent cations.

    PubMed

    Schäfer, R; Reiser, G

    1997-07-01

    1. We made a comparative analysis of the binding characteristics of the radioligands [35S]-ATP alpha S and [3H]-alpha, beta-MeATP in order to test whether these ligands can be used to analyse P2-purinoceptors in synaptosomal membranes from rat brain cortex. 2. Synaptosomes possess sites with high affinity for [35S]-ATP alpha S (Kd = 22.2 +/- 9.1 nM, Bmax = 14.8 pmol mg-1 protein). The rank order of the competition potency of the different compounds (ATP alpha S, ATP, ATP gamma S > ADP beta S, 2-MeSATP > deoxyATP, ADP > > UTP, alpha, beta-MeATP, AMP, Reactive Blue-2, suramin, isoPPADS) is consistent with pharmacological properties of P2Y-purinoceptors. 3. Under identical conditions [35S]-ATP alpha S and [3H]-alpha, beta-MeATP bind to different binding sites at synaptosomal membranes from rat brain cortex. The affinity of the [3H]-alpha, beta-MeATP binding sites (Kd = 13.7 +/- 1.8 nM, Bmax = 6.34 +/- 0.28 pmol mg-1 protein) was 38 fold higher than the potency of alpha, beta-MeATP to displace [35S]-ATP alpha S binding (Ki = 0.52 microM). ATP and ADP beta S competed at both binding sites with different affinities, 60 fold and 175 fold, respectively. The other agonists tested (2-MeSATP, UTP, GTP) did not affect specific [35H]-alpha, beta-MeATP binding at concentrations up to 100 microM. The antagonists (suramin, isoPPADS, Evan's Blue) showed completely different affinities for both binding sites. 4. Binding of [35S]-ATP alpha S on synaptosomes was regulated by GTP, which is indicative for G-protein coupled receptors. The Kd value for the high affinity binding site was reduced in the presence of GTP about 5 fold (from 1.8 nM to 8.6 nM). In the presence of Mg2+ the affinity was increased (Kd 1.8 nM versus 22 nM in the absence of Mg2+). 5. The binding of both radioligands was regulated in an opposite manner by physiological concentrations of Ca2+ and Mg2+. Binding of [3H]-alpha, beta-MeATP to synaptosomal membranes was increased 3 fold by raising the Ca2+ concentration

  20. Comparison of ( sup 3 H)Phencyclidine (( sup 3 H)PCP) and ( sup 3 H) N-(1-(2-thienyl) cyclohexyl)piperidine (( sup 3 H)TCP) binding properties to rat and human brain membranes

    SciTech Connect

    Vignon, J.; Chaudieu, I.; Allaoua, H.; Journod, L.; Javoy-Agid, F.; Agid, Y.; Chicheportiche, R.

    1989-01-01

    The investigation of ({sup 3}H)PCP and ({sup 3}H)TCP binding properties to rat cerebrum and cerebellum resulted in the demonstration of multiple binding sites for the two drugs. In the two tissue preparations PCP had a lower affinity than TCP. In membranes from the cerebrum an equal number of high affinity binding sites were present for ({sup 3}H)PCP and ({sup 3}H)TCP. However, low affinity binding sites were two times more numerous for ({sup 3}H)PCP than for ({sup 3}H)TCP. In the cerebellum, the number of high and low affinity sites labeled by the two radioligands was identical, but the number of high affinity sites was about 7 fold lower than in cerebrum. In human cerebral cortex samples ({sup 3}H)TCP also bound to two different sites. The number of high and low affinity sites were 12 and 3 times, respectively, less abundant than in the rat cerebrum. Low affinity sites were of higher affinity than corresponding sites in the rat brain. In the human cerebellum ({sup 3}H)TCP binding parameters were identical to those measured in the same region in the rat.

  1. NMR discrimination in nonrigid prochiral solutes dissolved in chiral liquid crystals: symmetry considerations.

    PubMed

    Lesot, Philippe; Luz, Zeev; Aroulanda, Christie; Zimmermann, Herbert

    2014-10-01

    Enantiodiscrimination in the NMR spectra of flexible prochiral solutes dissolved in chiral liquid crystals (CLCs) is reviewed and compared with the analog phenomenon in such rigid solutes. In rigid prochiral solutes, the discrimination is brought about by the cancellation of improper symmetry elements upon dissolving in CLC within the frame of solute-solvent ordering mechanisms. If this reduction in symmetry renders the ordering of enantiotopic sites dissimilar, spectral discrimination may be observed. Symmetry considerations indicate that this is only possible for improper nonaxial groups lacking inversion symmetry. Nonrigid prochiral solutes consist of rapidly (on the NMR timescale) interconverting enantiomers, in which the racemization is accompanied by exchange of nonequivalent sites. These sites become, on the average, enantiotopically related, and in CLC, they exhibit spectral discrimination. The mechanism of the effect and the symmetry selection rules are different for the two cases. Specifically, the discrimination in flexible prochiral compounds results from the different ordering of the interchanging enantiomers in CLC. Using Altman's definition of average symmetry (Proc. R. Soc. A, 1967, 298, 184), selection rules for the phenomenon are derived. It follows that chiral discrimination in nonrigid prochiral solutes is much more abundant and can occur in all symmetry types except those possessing inversion. In particular, contrary to earlier thoughts, the effect can occur in compounds with axial symmetry. Illustrative examples of such studies with particular emphasis on compounds with average axial symmetry of the type D(3h), C(3v) and C(3h) are reviewed in this contribution.

  2. [3H]Ethynylbicycloorthobenzoate ([3H]EBOB) binding in recombinant GABAA receptors.

    PubMed

    Yagle, Monica A; Martin, Michael W; de Fiebre, Christopher M; de Fiebre, NancyEllen C; Drewe, John A; Dillon, Glenn H

    2003-12-01

    Ethynylbicycloorthobenzoate (EBOB) is a recently developed ligand that binds to the convulsant site of the GABAA receptor. While a few studies have examined the binding of [3H]EBOB in vertebrate brain tissue and insect preparations, none have examined [3H]EBOB binding in preparations that express known configurations of the GABAA receptor. We have thus examined [3H]EBOB binding in HEK293 cells stably expressing human alpha1beta2gamma2 and alpha2beta2gamma2 GABAA receptors, and the effects of CNS convulsants on its binding. The ability of the CNS convulsants to displace the prototypical convulsant site ligand, [35S]TBPS, was also assessed. Saturation analysis revealed [3H]EBOB binding at a single site, with a K(d) of approximately 9 nM in alpha1beta2gamma2 and alpha2beta2gamma2 receptors. Binding of both [3H]EBOB and [35S]TBPS was inhibited by dieldrin, lindane, tert-butylbicycloorthobenzoate (TBOB), PTX, TBPS, and pentylenetetrazol (PTZ) at one site in a concentration-dependent fashion. Affinities were in the high nM to low microM range for all compounds except PTZ (low mM range), and the rank order of potency for these convulsants to displace [3H]EBOB and [35S]TBPS was the same. Low [GABA] stimulated [3H]EBOB binding, while higher [GABA] (greater than 10 microM) inhibited [3H]EBOB binding. Overall, our data demonstrate that [3H]EBOB binds to a single, high affinity site in alpha1beta2gamma2 and alpha2beta2gamma2 GABAA receptors, and modulation of its binding is similar to that seen with [35S]TBPS. [3H]EBOB has a number of desirable traits that may make it preferable to [35S]TBPS for analysis of the convulsant site of the GABAA receptor.

  3. Symmetry restoring and ancilla-driven entanglement for ultra-cold spin-1 atoms in a three-site ring

    NASA Astrophysics Data System (ADS)

    Barasiński, Artur; Leoński, Wiesław

    2017-01-01

    The spin-change dynamics of a model with ultra-cold hyperfine-spin-1 atoms confined in an optical superlattice is discussed. First, the disturbance of the two-site dynamics by coupling the dimer to a spin-1 ancilla is analyzed. When the dimer is coupled to the ancilla, even by a weak coupling, the significant changes in the system's time-evolution processes are observed. Next, we show that for the two-particle case the total hyperfine-spin-singlet state is generated by exploiting a quadratic Zeeman shift with realistic values of the strength of external magnetic field and evolution period of time. Moreover, even in a weak coupling regime, the proper choice of the additional ancilla-dimer interaction results in generating the wave function which is characteristic of the homogeneous three-site ring. In consequence, such wave function exhibits translational invariance symmetry despite the strong asymmetry of the lattice. Furthermore, we present our proposal for extracting various kinds of maximally entangled states (MES) for three-site spin-1 systems, starting from initial product states. In particular, we show that the type of generated MES can be unambiguously recognized by the measurement performed on the ancilla.

  4. Comparison of (/sup 3/H)nicotine and (/sup 3/H)acetylcholine binding in mouse brain: regional distribution

    SciTech Connect

    Sershen, H.; Reith, M.E.; Hashim, A.; Lajtha, A.

    1985-06-01

    In a continuing study of nicotine binding sites, the authors determined the relative amount of nicotine binding and acetylcholine binding in various brain regions of C57/BL and of DBA mice. Although midbrain showed the highest and cerebellum the lowest binding for both (/sup 3/H)nicotine and (/sup 3/H)acetylcholine, the ratio of nicotine to acetylcholine binding showed a three-fold regional variation. Acetylcholine inhibition of (/sup 3/H)nicotine binding indicated that a portion of nicotine binding was not inhibited by acetylcholine. These results indicate important differences between the binding of (+/-)-(/sup 3/H)nicotine and that of (/sup 3/H)acetylcholine.

  5. Binding of [3H]-prazosin and [3H]-dihydroergocryptine to rat cardiac alpha-adrenoceptors.

    PubMed Central

    Guicheney, P.; Meyer, P.

    1981-01-01

    1 [3H]-prazosin binds specifically to a single class of alpha-adrenoceptors in rat cardiac membranes (KD25 degrees C = 0.2 nM). 2 That these receptors are of the alpha 1-type was indicated by competition studies, i.e. alpha 1-antagonists such as prazosin and (2-(2,6-dimethoxyphenoxyethyl) aminomethyl-1, 4-benzodioxane (WB 4101) were more potent than the alpha 2-antagonists, yohimbine and piperoxan in inhibiting [3H]-prazosin binding. 3 A comparative study of [3H]-prazosin binding and [3H]-dihydroergocryptine binding to cardiac membranes showed that both [3H]-prazosin and [3H]-dihydroergocryptine (at low concentrations) bind to alpha 2-adrenoceptors, while [3H]-dihydroergocryptine (at higher concentrations) also binds to another class of sites. PMID:6269682

  6. Symmetries of migration related segments of all [001] coincidence site lattice tilt boundaries in (001) projections for all holohedral cubic materials

    SciTech Connect

    Moeck, Peter; York, Bryant W.; Browning, Nigel D.

    2014-09-11

    Utilizing bicrystallography in two dimensions (2D), the symmetries of migration related segments of Coincidence Site Lattice (CSL) boundaries are derived for projections along their [001] tilt axis in grain boundaries of crystalline materials that possess the holohedral point symmetry of the cubic system (i.e. m3m). These kinds of “edge-on” projections are typical for atomic resolution imaging of such tilt boundaries with Transmission Electron Microscopes (TEM). This fact facilitates the visual confirmation of our predictions by recently published Zcontrast scanning TEM investigations [H. Yang et al., Phil. Mag. 93 (2013) 1219] and many other TEM studies.

  7. Muon Capture on ^3H

    NASA Astrophysics Data System (ADS)

    Golak, Jacek; Skibiński, Roman; Witała, Henryk; Topolnicki, Kacper; Kamada, Hiroyuki; Nogga, Andreas; Marcucci, Laura E.

    2017-01-01

    The μ ^- + ^3H → ν _μ + n + n + n capture reaction is studied under full inclusion of final-state interactions with the AV18 nucleon-nucleon potential and the Urbana IX three-nucleon force. We employ the single nucleon weak current operator comprising the dominant relativistic corrections to obtain first estimates of the total capture rates based on realistic forces. Our results are compared with older theoretical predictions.

  8. The Use of the Free, Open-Source Program Jmol to Generate an Interactive Web Site to Teach Molecular Symmetry

    ERIC Educational Resources Information Center

    Cass, Marion E.; Rzepa, Henry S.; Rzepa, David S.; Williams, Charlotte K.

    2005-01-01

    The ability to design and to aspire of the future design of three-dimensional molecular animations to teach molecular symmetry is an exciting outcome of computer-driven technologies. Some of the details and vital issues addressed in developing a set of Web pages to teach molecular symmetry at Imperial College London using crafted animations are…

  9. Polarization properties and disorder effects in H{sub 3} photonic crystal cavities incorporating site-controlled, high-symmetry quantum dot arrays

    SciTech Connect

    Surrente, Alessandro; Felici, Marco; Gallo, Pascal; Dwir, Benjamin; Rudra, Alok; Kapon, Eli; Biasiol, Giorgio

    2015-07-20

    We report on the effects of optical disorder on breaking the symmetry of the cavity modes of H{sub 3} photonic crystal cavities incorporating site-controlled pyramidal quantum dots (QDs) as the internal light source. The high in-plane symmetry of the polarization states of the pyramidal QDs simplifies the analysis of the polarization states of the H{sub 3} cavities. It is shown that the optical disorder induced by fabrication imperfections lifts the degeneracy of the two quadrupole cavity modes and tilts the elongation axes of the cavity mode patterns with respect to the ideal, hexagonal symmetry case. These results are useful for designing QD-cavity structures for polarization-entangled photon sources and few-QD lasers.

  10. (/sup 3/H)-beta-endorphin binding in rat brain

    SciTech Connect

    Houghten, R.A.; Johnson, N.; Pasternak, G.W.

    1984-10-01

    The binding of (/sup 3/H)-beta-endorphin to rat brain homogenates is complex. Although Scatchard analysis of saturation studies yields a straight line, detailed competition studies are multiphasic, suggesting that even at low concentrations of the compound, the /sup 3/H-ligand is binding to more than one class of site. A portion of (/sup 3/H)-beta-endorphin binding is sensitive to low concentrations of morphine or D-Ala2-Leu5-enkephalin (less than 5 nM). The inhibition observed with each compound alone (5 nM) is the same as that seen with both together (each at 5 nM). Thus, the binding remaining in the presence of both morphine and the enkephalin does not correspond to either mu or delta sites. The portion of (/sup 3/H)-beta-endorphin binding that is inhibited under these conditions appears to be equally sensitive to both morphine and the enkephalin and may correspond to mu1 sites. Treating membrane homogenates with naloxonazine, a mu1 selective antagonist, lowers (/sup 3/H)-beta-endorphin binding to the same degree as morphine and D-Ala2-Leu5-enkephalin alone or together. This possible binding of (/sup 3/H)-beta-endorphin to mu1 sites is consistent with the role of mu1 sites in beta-endorphin analgesia and catalepsy in vivo.

  11. Symmetry impedes symmetry discrimination.

    PubMed

    Tjan, Bosco S; Liu, Zili

    2005-12-16

    Objects in the world, natural and artificial alike, are often bilaterally symmetric. The visual system is likely to take advantage of this regularity to encode shapes for efficient object recognition. The nature of encoding a symmetric shape, and of encoding any departure from it, is therefore an important matter in visual perception. We addressed this issue of shape encoding empirically, noting that a particular encoding scheme necessarily leads to a specific profile of sensitivity in perceptual discriminations. We studied symmetry discrimination using human faces and random dots. Each face stimulus was a frontal view of a three-dimensional (3-D) face model. The 3-D face model was a linearly weighted average (a morph) between the model of an original face and that of the corresponding mirror face. Using this morphing technique to vary the degree of asymmetry, we found that, for faces and analogously generated random-dot patterns alike, symmetry discrimination was worst when the stimuli were nearly symmetric, in apparent opposition to almost all studies in the literature. We analyzed the previous work and reconciled the old and new results using a generic model with a simple nonlinearity. By defining asymmetry as the minimal difference between the left and right halves of an object, we found that the visual system was disproportionately more sensitive to larger departures from symmetry than to smaller ones. We further demonstrated that our empirical and modeling results were consistent with Weber-Fechner's and Stevens's laws.

  12. Comparison of (/sup 3/H)pirenzepine and (/sup 3/H)quinuclidinylbenzilate binding to muscarinic cholinergic receptors in rat brain

    SciTech Connect

    Luthin, G.R.; Wolfe, B.B.

    1984-03-01

    The properties of (/sup 3/H)quinuclidinylbenzilate ( (/sup 3/H)QNB) binding and (/sup 3/H)pirenzepine ( (/sup 3/H)PZ) binding to various regions of rat brain were compared. (/sup 3/H)PZ appeared to bind with high affinity to a single site, with a Kd value of approximately 15 nM in the cerebral cortex. The rank order of potencies of muscarinic drugs to inhibit binding of either (/sup 3/H)QNB or (/sup 3/H)PZ was QNB greater than atropine . scopolamine greater than pirenzepine greater than oxotremorine greater than bethanechol. Muscarinic antagonists (except PZ) inhibited both (/sup 3/H)PZ and (/sup 3/H)QNB binding with Hill coefficients of approximately 1. PZ inhibited (/sup 3/H)QNB binding in cortex with a Hill coefficient of 0.7, but inhibited (/sup 3/H)PZ binding with a Hill coefficient of 1.0. Hill coefficients for agonists were less than 1. The density of (/sup 3/H)PZ binding sites was approximately half the density of (/sup 3/H)QNB binding sites in cortex, striatum and hippocampus. In pons-medulla and cerebellum, the densities of (/sup 3/H)PZ binding sites were 20 and 0%, respectively, relative to the densities of (/sup 3/H)QNB binding sites. When unlabeled PZ was used to compete for (/sup 3/H)QNB binding, the relative number of high-affinity PZ binding sites in cortex, pons and cerebellum agreed with the relative number of (/sup 3/H)PZ binding sites in those regions. The binding of (/sup 3/H)PZ and (/sup 3/H)QNB was nonadditive in cortex. GTP inhibited high-affinity oxotremorine binding, but not PZ binding. Together, these data suggest that (/sup 3/H)PZ binds to a subset of (/sup 3/H)QNB binding sites. Whether this subset reflects the existence of subtypes of muscarinic receptors or is a consequence of coupling to another membrane protein remains to be seen.

  13. (/sup 3/H) clonidine binding to rat hippocampal membranes

    SciTech Connect

    George, C.R.

    1982-02-01

    Alpha adrenergic receptor subtypes in rat hippocampal membranes were studied, using (/sup 3/H) clonidine as the radioactive ligand. On the basis of competitive binding studies, using the selective antagonist-prazosin, WB-4101, and yohimbine, (/sup 3/H) clonidine appeared to bind to a population of presynaptic sites that are pharmacologically similar to receptors previously classified as alpha 2. A computerized model that linearized and produced the best possible fit to the experimental data points indicated that (/sup 3/H) clonidine binds to a single population of receptors possessing equal affinity for the ligand. Binding data also indicated that rat hippo-campus contains significantly fewer (/sup 3/H)clonidine binding sites than rat cortex.

  14. In vivo binding of (/sup 3/H)Ro 15-1788 in mice: comparison with the in vivo binding of (/sup 3/H)flunitrazepam

    SciTech Connect

    Potier, M.C.; de Carvalho, L.P.; Dodd, R.H.; Brown, C.L.; Rossier, J.

    1988-01-01

    Benzodiazepine binding sites have generally been labelled with benzodiazepine agonists: (/sup 3/H)flunitrazepam and (/sup 3/H)diazepam in vivo. The authors studied the in vivo binding of the antagonist (/sup 3/H)Ro 15-1788 in mice and compared it to the in vivo binding of (/sup 3/H)flunitrazepam. For this in vivo labelling, mice were injected with labelled and unlabelled ligands. Animals were then sacrificed and bound radioactivity was measured after homogenization of the excised brain and filtration of the homogenate. (/sup 3/H)Ro 15-1788 is a better tool than (/sup 3/H)flunitrazepam for in vivo labelling of benzodiazepine receptors since 1) it labels specifically the central type binding sites, 2) injection of 4 times less (/sup 3/H)Ro 15-1788 than (/sup 3/H)flunitrazepam produced the same amount of bound radioactivity, 3) 70-90% of the total (/sup 3/H)Ro 15-1788 present in the brain is membrane bound instead of 45-55% with (/sup 3/H)flunitrazepam, 4) maximal binding of (/sup 3/H)Ro 15-1788 is reached within 3 min, 5) only 5% of the membrane bound (/sup 3/H)Ro 15-1788 is nonspecific instead of 15% for (/sup 3/H)flunitrazepam.

  15. Ubiquitous symmetries

    NASA Astrophysics Data System (ADS)

    Nucci, M. C.

    2016-09-01

    We review some of our recent work devoted to the problem of quantization with preservation of Noether symmetries, finding hidden linearity in superintegrable systems, and showing that nonlocal symmetries are in fact local. In particular, we derive the Schrödinger equation for the isochronous Calogero goldfish model using its relation to Darwin equation. We prove the linearity of a classical superintegrable system on a plane of nonconstant curvature. We find the Lie point symmetries that correspond to the nonlocal symmetries (also reinterpreted as λ-symmetries) of the Riccati chain.

  16. Effect of sequence of administration on the pharmacokinetic interaction between the anticholinergic drug biperiden and [3H]quinuclidinyl benzylate or [3H]N-methylscopolamine in rats.

    PubMed

    Ishizaki, J; Yokogawa, K; Nakashima, E; Takayasu, T; Ohshima, T; Ichimura, F

    1998-02-01

    In rats the pharmacokinetic interactions between the anticholinergic drug biperiden and [3H]quinuclidinyl benzylate ([3H]QNB) or [3H]N-methylscopolamine ([3H]NMS) is affected by the sequence in which the drugs are administered. Drug concentrations in various tissues were determined after intravenous administration of [3H]QNB or [3H]NMS (325 ng kg(-1)). Biperiden (6.4 mg kg(-1)) was administered either 5 min before, concomitantly with or 20 min after injection of [3H]QNB or [3H]NMS. When biperiden was administered concomitantly with or before [3H]QNB, distribution of [3H]QNB among the regions of the brain and other tissues was reduced; at 4 h the ratio of the distribution of [3H]QNB for experimental animals to that for control animals ranged from 0.15 to 0.9. When biperiden was administered after [3H]QNB, the distribution of [3H]QNB in the brain and other tissues was significantly higher than for the other two treatments (P < 0.01). However, for [3H]NMS the sequence of administration had no effect on the distribution of the drug in the brain and other tissues except for the kidney. In-vitro, in crude synaptosomal membranes, the amount of [3H]QNB at 2 h relative to the control concentration at equilibrium was 87% when biperiden was added before [3H]QNB and 56% when biperiden was added after [3H]QNB. In both instances the concentration of [3H]NMS reached equilibrium within 30 min. These findings suggest that the difference between the rate constant of association and dissociation at the possible site of action gives rise to the effect of the sequence of administration on the pharmacokinetic interaction.

  17. Renal Aldosterone Receptors: Studies with [3H]Aldosterone and the Anti-Mineralocorticoid [3H]Spirolactone (SC-26304)

    PubMed Central

    Marver, Diana; Stewart, John; Funder, John W.; Feldman, David; Edelman, Isidore S.

    1974-01-01

    In vivo, a spirolactone (SC-26304) inhibited the effects of aldosterone on urinary K+:Na+ ratios and the binding of [3H]aldosterone to renal cytoplasmic and nuclear receptors. Cytoplasmic binding of [3H]aldosterone and [3H]spirolactone (SC-26304) was similar in magnitude and involved the same set of sites. Under three sets of conditions—(i) in the intact rat, (ii) in kidney slices, and (iii) in reconstitution studies (mixing prelabeled cytoplasm with either purified renal nuclei or chromatin), [3H]spirolactone (SC-26304) did not yield specific nuclear complexes in contrast to the reproducible generation of these complexes with [3H]aldosterone. In glycerol density gradients, cytoplasmic [3H]aldosterone receptor complexes sedimented at 8.5 S and 4 S in low concentrations of salt and at 4.5 S in high concentrations of salt. Cytoplasmic [3H]spirolactone (SC-26304) receptor complexes sedimented at 3 S in low concentrations of salt and 4 S in high concentrations of salt. These results are discussed in terms of an allosteric model of the receptor system. Images PMID:4364539

  18. sigma opiates and certain antipsychotic drugs mutually inhibit (+)-(/sup 3/H)SKF 10,047 and (/sup 3/H)haloperidol binding in guinea pig brain membranes

    SciTech Connect

    Tam, S.W.; Cook, L.

    1984-09-01

    The relationship between binding of antipsychotic drugs and sigma psychotomimetic opiates to binding sites for the sigma agonist (+)-(/sup 3/H)SKF 10,047 (N-allylnormetazocine) and to dopamine D/sub 2/ sites was investigated. In guinea pig brain membranes, (+)-(/sup 3/H)SKF 10,047 bound to single class of sites with a K/sub d/ of 4 x 10/sup -8/ M and a B/sub max/ of 333 fmol/mg of protein. This binding was different from ..mu.., kappa, or delta opiate receptor binding. It was inhibited by opiates that produce psychotomimetic activities but not by opiates that lack such activities. Some antipsychotic drugs inhibited (+)-(/sup 3/H)SKF 10,047 binding with high to moderate affinities in the following order of potency: haloperidol > perphenazine > fluphenazine > acetophenazine > trifluoperazine > molindone greater than or equal to pimozide greater than or equal to thioridazine greater than or equal to chlorpromazine greater than or equal to triflupromazine. However, there were other antipsychotic drugs such as spiperone and clozapine that showed low affinity for the (+)-(/sup 3/H)SKF 10,047 binding sites. Affinities of antipsychotic drugs for (+)-(/sup 3/H)SKF 10,047 binding sites did not correlate with those for (/sup 3/H)spiperone (dopamine D/sub 2/) sites. (/sup 3/H)-Haloperidol binding in whole brain membranes was also inhibited by the sigma opiates pentazocine, cyclazocine, and (+)-(/sup 3/H)SKF 10,047. In the striatum, about half of the saturable (/sup 3/H)haloperidol binding was to (/sup 3/H)spiperone (D/sub 2/) sites and the other half was to sites similar to (+)-(/sup 3/H)SKF 10,047 binding sites. 15 references, 4 figures, 1 table.

  19. 3,4-Methylenedioxyamphetamine (MDA) analogues exhibit differential effects on synaptosomal release of 3H-dopamine and 3H-5-hydroxytryptamine

    SciTech Connect

    McKenna, D.J.; Guan, X.M.; Shulgin, A.T. )

    1991-03-01

    The effect of various analogues of the neurotoxic amphetamine derivative, MDA (3,4-methylenedioxyamphetamine) on carrier-mediated, calcium-independent release of 3H-5-HT and 3H-DA from rat brain synaptosomes was investigated. Both enantiomers of the neurotoxic analogues MDA and MDMA (3,4-methylenedioxymethamphetamine) induce synaptosomal release of 3H-5-HT and 3H-DA in vitro. The release of 3H-5-HT induced by MDMA is partially blocked by 10(-6) M fluoxetine. The (+) enantiomers of both MDA and MDMA are more potent than the (-) enantiomers as releasers of both 3H-5-HT and 3H-DA. Eleven analogues, differing from MDA with respect to the nature and number of ring and/or side chain substituents, also show some activity in the release experiments, and are more potent as releasers of 3H-5-HT than of 3H-DA. The amphetamine derivatives {plus minus}fenfluramine, {plus minus}norfenfluramine, {plus minus}MDE, {plus minus}PCA, and d-methamphetamine are all potent releasers of 3H-5-HT and show varying degrees of activity as 3H-DA releasers. The hallucinogen DOM does not cause significant release of either 3H-monoamine. Possible long-term serotonergic neurotoxicity was assessed by quantifying the density of 5-HT uptake sites in rats treated with multiple doses of selected analogues using 3H-paroxetine to label 5-HT uptake sites. In the neurotoxicity study of the compounds investigated, only (+)MDA caused a significant loss of 5-HT uptake sites in comparison to saline-treated controls. These results are discussed in terms of the apparent structure-activity properties affecting 3H-monoamine release and their possible relevance to neurotoxicity in this series of MDA congeners.

  20. Theoretical exploration of hydrogen loss from Al3H9.

    PubMed

    Nold, Christopher P; Head, John D

    2012-05-03

    The Al(3)H(9) and Al(3)H(7) potential energy surfaces were explored using quantum chemistry calculations to investigate the H(2) loss mechanism from Al(3)H(9), which provide new insights into hydrogen production from bulk alane, [AlH(3)](x), a possible energy storage material. We present results of B3LYP/6-311++G(d,p) calculations for the various Al(3)H(9) and Al(3)H(7) optimized local minima and transition state structures along with some reaction pathways for their interconversion. We find the energy for Al(3)H(9) decomposition into Al(2)H(6) and AlH(3) is slightly lower than that for H(2) loss and Al(3)H(7) formation, but the calculations show that H(2) loss from Al(3)H(9) is a lower energy process than for losing hydrogen from either Al(2)H(6) or AlH(3). We found four transition state structures and reaction pathways for Al(3)H(9) → Al(3)H(7) + H(2), where the lowest energy activation barrier is around 25-73 kJ/mol greater than the experimental value for H(2) loss from bulk alane. Intrinsic reaction coordinate calculations show that the H(2) loss pathway involves considerable rearrangement of the H atom positions around a single Al center. Three of the pathways start with the formation of an AlH(3) moiety, which then enables a terminal H on the AlH(3) to get within 1.1 to 1.2 Å of a nearby bridging H atom. The bridging and terminal H atoms eventually combine to form H(2) and leave Al(3)H(9). One implication of these H(2) loss reaction pathways is that, since the H atoms in bulk alanes are all at bridging positions, if a similar H(2) loss mechanism were to apply to bulk alane, then H(2) loss would most likely occur on the bulk alane surface or at a defect site where there should be more terminal H atoms available for reaction with nearby bridging H atoms.

  1. Clinical and treatment effects on /sup 3/H-clonidine and /sup 3/H-imipramine binding in elderly depressed patients

    SciTech Connect

    Georgotas, A.; Schweitzer, J.; McCue, R.E.; Armour, M.; Friedhoff, A.J.

    1987-06-01

    /sup 3/H-clonidine and /sup 3/H-imipramine binding were measured in depressed patients, 55 years and older. There was no significant difference in either /sup 3/H-clonidine or /sup 3/H-imipramine binding between depressed patients and age- and sex-matched controls. There was no significant correlation between /sup 3/H-clonidine or /sup 3/H-imipramine binding and severity of depression before treatment. There was a significant negative correlation between the K/sub D/ of /sup 3/H-imipramine binding sites and Hamilton score over seven weeks of antidepressant treatment. There was no significant difference between receptor data of responders and nonresponders to antidepressant treatment. 19 references, 2 tables.

  2. Symmetry matters.

    PubMed

    Moubayidin, Laila; Østergaard, Lars

    2015-09-01

    985 I. 985 II. 986 III. 987 IV. 988 V. 989 989 References 989 SUMMARY: The development of multicellular organisms depends on correct establishment of symmetry both at the whole-body scale and within individual tissues and organs. Setting up planes of symmetry must rely on communication between cells that are located at a distance from each other within the organism, presumably via mobile morphogenic signals. Although symmetry in nature has fascinated scientists for centuries, it is only now that molecular data to unravel mechanisms of symmetry establishment are beginning to emerge. As an example we describe the genetic and hormonal interactions leading to an unusual bilateral-to-radial symmetry transition of an organ in order to promote reproduction.

  3. Hemispheric Symmetries of Plio-Pleistocene Surface Ocean Conditions: Insights from Southern Hemisphere ODP Sites 1125 and 1088

    NASA Astrophysics Data System (ADS)

    Lawrence, K. T.; Peterson, L.; Kelly, C.; Miller, H.; Seidenstein, J.

    2013-12-01

    For decades, most studies of Plio-Pleistocene climate and of the transition from the warmth of the Pliocene to the colder and more variable conditions of the Pleistocene have focused solely on northern hemisphere climate processes and responses. Here, we explore the southern hemisphere response to this major climate transition by documenting ocean surface conditions at Ocean Drilling Program Sites 1125 (42οS, 178οW, 1360m) and 1088 (40οS, 15οE, 2082m) through the Plio-Pleistocene. Secular trends in alkenone-derived sea surface temperature (SST) records indicate that these mid-latitude southern hemisphere sites cooled ~3-4οC over the past 3 Myrs, a magnitude comparable to sites located at similar latitudes in both the North Atlantic and North Pacific. This observation suggests that contraction of the low latitude warm pool was hemispherically symmetric. Our highly resolved (3 kyr resolution) Site 1125 SST record bears considerable structural similarity to SST records from nearby site 1123 (42οS,171οW) as well as sites 846 (3οS, 91οW) in the eastern equatorial Pacific and U1313 (41οN, 33οW) in the North Atlantic. Most of these SST records are dominated by 100k power and contain strong secondary 41k peaks throughout the past 3 million years. North Atlantic site U1313 is the exception, mirroring the shift in dominant periodicity from 41k to 100k associated with the mid-Pleistocene transition, that has long been observed in benthic oxygen isotope records. Finally, in southern hemisphere SST records as well as at site U1313 from the north Atlantic we observe weak precessional power that is not evident in benthic oxygen isotope record. These results suggest a fairly hemispherically-coordinated response of ocean surface temperature to changing global climate conditions during the Plio-Pleistocene in terms of both secular trends and dominant orbital frequencies.

  4. Dissociative electron attachment to methylacetylene and dimethylacetylene: Symmetry versus proximity

    NASA Astrophysics Data System (ADS)

    Janečková, R.; May, O.; Fedor, J.

    2012-11-01

    We have measured absolute dissociative electron attachment (DEA) cross sections in methylacetylene (propyne, C3H4) and dimethylacetylene (but-2-yne, C4H6). The main feature in the low-energy DEA spectrum is a π* shape resonance giving rise to fragments at 3.4 eV in C3H4 and 4.0 eV in C4H6. The process C3H4+e→ C3H3-+H proceeds via abstraction of the acetylenic hydrogen which is mediated by effective vibronic coupling. The abstraction of methyl group hydrogen, which does not require symmetry lowering of the transient negative ion, was not observed; the spatial separation of the bond from the resonance decreases the cross section dramatically. The presence of the methyl group further influences the DEA cross sections via change of the resonance's position and via blocking one or both of the DEA active sites in acetylene. No cleavage of the C-methyl bond has been observed, and reasons for this effect are discussed. Additionally, several higher-lying resonances (6 to 15 eV) leading to production of an H- fragment were observed and assigned.

  5. (/sup 3/H)nitrendipine binding to adrenal capsular membranes

    SciTech Connect

    Finkel, M.S.; Aguilera, G.; Catt, K.J.; Keiser, H.R.

    1984-08-20

    The physiologic regulation of aldosterone secretion is dependent on extracellular calcium and appears to be mediated by increases in cytosolic free calcium concentration in the zona glomerulosa cell. A specific role for voltage-dependent calcium channels was suggested by previous studies with the calcium channel antagonist verapamil. The authors therefore studied the (/sup 3/H)nitrendipine calcium channel binding site in adrenal capsules. These studies revealed a single class of saturable, high affinity sites with K/sub D/ = .26 +/- .04 nM and B/sub max/ = 105 +/- 5.7 fmol/mg protein. Specific binding of (/sup 3/H)nitrendipine was inhibited by calcium channel antagonists with potencies nitrendipine = nifedipine >> verapamil, while diltiazem had no inhibitory effect. In the rat, binding sites for (/sup 3/H)nitrendipine were located in the adrenal capsule and medulla and were undetectable in the zona fasciculata. Physiologic studies with collagenase-dispersed adrenal glomerulosa cells demonstrated that nifedipine selectively inhibited angiotensin-II and potassium-stimulated steroidogenesis. These observations suggest both a pharmacologic and physiologic role for the nitrendipine binding site in aldosterone production. 17 references, 2 figures, 1 table.

  6. Hydrogen-bond-directed assemblies of [La(18-crown-6)(H2O)4](BiCl6)·3H2O and [Nd(18-crown-6)(H2O)4](BiCl6)·3.5H2O regulated by different symmetries

    NASA Astrophysics Data System (ADS)

    Zhang, Shi-Yong; Li, Jian; Zeng, Ying; Wen, He-Rui; Du, Zi-Yi

    2016-12-01

    The reactions of La2O3 or Nd2O3 with BiCl3 and 18-crown-6 in the presence of excessive hydrochloric acid afforded two ion-pair compounds, namely [La(18-crown-6)(H2O)4](BiCl6)·3H2O (1) and [Nd(18-crown-6)(H2O)4](BiCl6)·3.5H2O (2). Although these two compounds contain similar building blocks, they exhibit two distinct hydrogen-bonded networks, which are mainly induced by the slightly different geometries of their large-sized cationic [Ln(18-crown-6)(H2O)4]3+ components.

  7. Intrinsically incompatible crystal (ligand) field parameter sets for transition ions at orthorhombic and lower symmetry sites in crystals and their implications

    NASA Astrophysics Data System (ADS)

    Rudowicz, C.; Gnutek, P.

    2010-01-01

    Central quantities in spectroscopy and magnetism of transition ions in crystals are crystal (ligand) field parameters (CFPs). For orthorhombic, monoclinic, and triclinic site symmetry CF analysis is prone to misinterpretations due to large number of CFPs and existence of correlated sets of alternative CFPs. In this review, we elucidate the intrinsic features of orthorhombic and lower symmetry CFPs and their implications. The alternative CFP sets, which yield identical energy levels, belong to different regions of CF parameter space and hence are intrinsically incompatible. Only their ‘images’ representing CFP sets expressed in the same region of CF parameter space may be directly compared. Implications of these features for fitting procedures and meaning of fitted CFPs are categorized into negative: pitfalls and positive: blessings. As a case study, the CFP sets for Tm 3+ ions in KLu(WO 4) 2 are analysed and shown to be intrinsically incompatible. Inadvertent, so meaningless, comparisons of incompatible CFP sets result in various pitfalls, e.g., controversial claims about the values of CFPs obtained by other researchers as well as incorrect structural conclusions or faulty systematics of CF parameters across rare-earth ion series based on relative magnitudes of incompatible CFPs. Such pitfalls bear on interpretation of, e.g., optical spectroscopy, inelastic neutron scattering, and magnetic susceptibility data. An extensive survey of pertinent literature was carried out to assess recognition of compatibility problems. Great portion of available orthorhombic and lower symmetry CFP sets are found intrinsically incompatible, yet these problems and their implications appear barely recognized. The considerable extent and consequences of pitfalls revealed by our survey call for concerted remedial actions of researchers. A general approach based on the rhombicity ratio standardization may solve compatibility problems. Wider utilization of alternative CFP sets in the

  8. Ethanol intake and sup 3 H-serotonin uptake II: A study in alcoholic patients using platelets sup 3 H-paroxetine binding

    SciTech Connect

    Daoust, M.; Boucly, P. ); Ernouf, D. ); Breton, P. ); Lhuintre, J.P.

    1991-01-01

    The kinetic parameters of {sup 3}H-paroxetine binding and {sup 3}H-serotonin uptake were studied in platelets of alcoholic patients. There was no difference between alcoholic and non alcoholic subjects in {sup 3}H-paroxetine binding. When binding and {sup 3}H-serotonin uptake were studied, in the same plasma of the same subjects, the Vmax of serotonin uptake was increased in alcoholics. The data confirm the involvement of serotonin uptake system in alcohol dependance and suggest that serotonin uptake and paroxetine binding sites may be regulated independently in this pathology.

  9. Light microscopic autoradiographic localization of (/sup 3/H)pirenzepine and (/sup 3/H)(/sup -/)quinuclidinyl benzilate binding in human stellate ganglia

    SciTech Connect

    Yamamura, H.I.; Watson, M.; Wamsley, J.K.; Johnson, P.C.; Roeske, W.R.

    1984-08-13

    The LKB Ultrofilm method of autoradiography has been utilized to anatomically localize putative M/sub 1/ and M/sub 2/ muscarinic receptor subtypes in human stellate ganglia. Ten micron sections were labeled in vitro with either 1 nM of the classical antagonist (/sup 3/H)(/sup -/)quinuclidinyl benzilate ((/sup 3/H)(/sup -/)QNB) or 20 nM of the non-classical antagonist (/sup 3/H)pirenzepine ((/sup 3/H)PZ), using 1 ..mu..M atropine sulfate to define non-specific binding for both ligands. The results indicate that (/sup 3/H)(/sup -/)QNB and (/sup 3/H)PZ binding sites are distributed within the principal ganglion cells and nerve bundles.

  10. High affinity binding of [3H]-tyramine in the central nervous system.

    PubMed Central

    Vaccari, A.

    1986-01-01

    Optimum assay conditions for the association of [3H]-para-tyramine [( 3H]-pTA) with rat brain membranes were characterized, and a saturable, reversible, drug-specific, and high affinity binding mechanism for this trace amine was revealed. The binding capacity (Bmax) for [3H]-pTA in the corpus striatum was approximately 30 times higher than that in the cerebellum, with similar dissociation constants (KD). The binding process of [3H]-pTA involved the dopamine system, inasmuch as (a) highest binding capacity was associated with dopamine-rich regions; (b) dopamine and pTA equally displaced specifically bound [3H]-pTA; (c) there was a severe loss in striatal binding capacity for [3H]-pTA and, reportedly, for [3H]-dopamine, following unilateral nigrostriatal lesion; (d) acute in vivo reserpine treatment markedly decreased the density of [3H]-pTA and, reportedly, of [3H]-dopamine binding sites. In competition experiments [3H]-pTA binding sites, though displaying nanomolar affinity for dopamine, revealed micromolar affinities for the dopamine agonists apomorphine and pergolide, and for several dopamine antagonists, while having very high affinity for reserpine, a marker for the catecholamine transporter in synaptic vesicles. The binding process of [3H]-pTA was both energy-dependent (ouabain-sensitive), and ATP-Mg2+-insensitive; furthermore, the potencies of various drugs in competing for [3H]-pTA binding to rat striatal membranes correlated well (r = 0.96) with their reported potencies in inhibiting [3H]-dopamine uptake into striatal synaptosomes. It is concluded that [3H]-pTA binds at a site located on/within synaptic vesicles where it is involved in the transport mechanism of dopamine. PMID:3801770

  11. In vivo labeling of cocaine receptors with sup 3 H-(-) cocaine, sup 3 H-WIN 35,065-2 and sup 3 H-WIN 35,428

    SciTech Connect

    Scheffel, U.; Boja, J.W.; Stathis, M.; Kuhar, M.J. )

    1990-02-26

    {sup 11}C-(-)cocaine (-COC) has recently been employed to image -COC binding sites in vivo using PET. Two analogs of -COC, WIN 35,065-2 (WIN-2) and WIN 35,428 (CFT), have been shown in vitro to exhibit higher affinity for the -COC receptor than -COC. The present study evaluates {sup 3}H-WIN-2 and {sup 3}H-CFT as in vivo receptor labels in mice with a view towards the use of these compounds as PET ligands for -COC receptors in the living human brain. {sup 3}H-labeled -COC, WIN-2 and CFT were injected i.v. into mice and their specific binding in the CNS determined. Peak striatal/cerebellar (S/C) ratios were reached at 5 minutes post injection with -COC (1.56), at 45 minutes with {sup 3}H-WIN-2 (3.30) and 60 minutes with {sup 3}H-CFT (4.0). The specificity of in vivo binding of {sup 3}H-WIN-2 and {sup 3}H-CFT was tested by pre-injection of various drugs. Binding of {sup 3}H-WIN-2 and {sup 3}H-CFT was dose-dependently blocked by cold WIN-2 and CFT, and by dopamine uptake site inhibitors (mazindol, GBR 12,909, nomifensine), but not by (+)COC, paroxetine and desipramine. The data indicate that {sup 3}H-WIN-2 and {sup 3}H-CFT exhibit improved in vivo binding (higher S/C ratios, longer retention time at the -COC receptor/dopamine transporter) compared to -COC and support their testing in PET studies.

  12. Characterization of (/sup 3/H)pirenzepine binding to muscarinic cholinergic receptors solubilized from rat brain

    SciTech Connect

    Luthin, G.R.; Wolfe, B.B.

    1985-07-01

    Membranes prepared from rat cerebral cortex were solubilized in buffer containing 1% digitonin. Material present in the supernatant after centrifugation at 147,000 X g was shown to contain binding sites for both (/sup 3/H)quinuclidinyl benzilate ((/sup 3/H)QNB) and (/sup 3/H)pirenzepine ((/sup 3/H)PZ). Recovery of binding sites was approximately 25% of the initial membrane-bound (/sup 3/H)QNB binding sites. The Kd values for (/sup 3/H)QNB and (/sup 3/H)PZ binding to solubilized receptors were 0.3 nM and 0.1 microM, respectively. As has been observed previously in membrane preparations, (/sup 3/H)PZ appeared to label fewer solubilized binding sites than did (/sup 3/H)QNB. Maximum binding values for (/sup 3/H)PZ and (/sup 3/H)QNB binding to solubilized receptors were approximately 400 and 950 fmol/mg of protein, respectively. Competition curves for PZ inhibiting the binding of (/sup 3/H)QNB, however, had Hill slopes of 1, with a Ki value of 0.24 microM. The k1 and k-1 for (/sup 3/H)PZ binding were 3.5 X 10(6) M-1 min-1 and 0.13 min-1, respectively. The muscarinic receptor antagonists atropine, scopolamine and PZ inhibited the binding of (/sup 3/H)QNB and (/sup 3/H)PZ to solubilized receptors with Hill slopes of 1, as did the muscarinic receptor agonist oxotremorine. The muscarinic receptor agonist carbachol competed for (/sup 3/H)QNB and (/sup 3/H)PZ binding with a Hill slope of less than 1 in cerebral cortex, but not in cerebellum. GTP did not alter the interactions of carbachol or oxotremorine with the solubilized receptor. Together, these data suggest that muscarinic receptor sites solubilized from rat brain retain their abilities to interact selectively with muscarinic receptor agonists and antagonists.

  13. Inherited Symmetry

    ERIC Educational Resources Information Center

    Attanucci, Frank J.; Losse, John

    2008-01-01

    In a first calculus course, it is not unusual for students to encounter the theorems which state: If f is an even (odd) differentiable function, then its derivative is odd (even). In our paper, we prove some theorems which show how the symmetry of a continuous function f with respect to (i) the vertical line: x = a or (ii) with respect to the…

  14. Purification of L-( sup 3 H) Nicotine eliminates low affinity binding

    SciTech Connect

    Romm, E.; Marks, M.J.; Collins, A.C. ); Lippiello, P.M. )

    1990-01-01

    Some studies of L-({sup 3}H) nicotine binding to rodent and human brain tissue have detected two binding sites as evidenced by nonlinear Scatchard plots. Evidence presented here indicated that the low affinity binding site is not stereospecific, is not inhibited by low concentrations of cholinergic agonists and is probably due to breakdown products of nicotine since purification of the L-({sup 3}H)nicotine eliminates the low affinity site.

  15. Conformational changes in the H3. H4 histone complex

    SciTech Connect

    Feldman, L.; Beaudette, N.V.; Stollar, B.D.; Fasman, G.D.

    1980-08-10

    The H3.H4 complex has been extracted from calf thymus chromatin in either 0.05 M NaOAc, pH 5.0, or in 2.0 M KCl, 0.1 M KPO/sub 4/, pH 6.7, and both forms have been shown to consist solely of histones H3 and H4 when examined on sodium dodecyl sulfate-polyacrylamide gels. Serological and circular dichroism analyses indicate the existence of structural differences between the two forms. Dilution of the high salt form of the complex into low salt produces a time-dependent conformational change which is related to reduction in the ..cap alpha.. helix content of the complex and which exposes antigenic sites on the complex. The existence of multiple forms of the H3.H4 complex may be related to the dynamic equilibrium of nucleosome structure in vivo.

  16. High-affinity binding of (/sup 3/H)acetylcholine to muscarinic cholinergic receptors

    SciTech Connect

    Kellar, K.J.; Martino, A.M.; Hall, D.P. Jr.; Schwartz, R.D.; Taylor, R.L.

    1985-06-01

    High-affinity binding of (/sup 3/H)acetylcholine to muscarinic cholinergic sites in rat CNS and peripheral tissues was measured in the presence of cytisin, which occupies nicotinic cholinergic receptors. The muscarinic sites were characterized with regard to binding kinetics, pharmacology, anatomical distribution, and regulation by guanyl nucleotides. These binding sites have characteristics of high-affinity muscarinic cholinergic receptors with a Kd of approximately 30 nM. Most of the muscarinic agonist and antagonist drugs tested have high affinity for the (/sup 3/H)acetylcholine binding site, but pirenzepine, an antagonist which is selective for M-1 receptors, has relatively low affinity. The ratio of high-affinity (/sup 3/H)acetylcholine binding sites to total muscarinic binding sites labeled by (/sup 3/H)quinuclidinyl benzilate varies from 9 to 90% in different tissues, with the highest ratios in the pons, medulla, and heart atrium. In the presence of guanyl nucleotides, (/sup 3/H) acetylcholine binding is decreased, but the extent of decrease varies from 40 to 90% in different tissues, with the largest decreases being found in the pons, medulla, cerebellum, and heart atrium. The results indicate that (/sup 3/H)acetylcholine binds to high-affinity M-1 and M-2 muscarinic receptors, and they suggest that most M-2 sites have high affinity for acetylcholine but that only a small fraction of M-1 sites have such high affinity.

  17. Nicotinic binding in rat brain: autoradiographic comparison of (/sup 3/H)acetylcholine, (/sup 3/H)nicotine, and (/sup 125/I)-alpha-bungarotoxin

    SciTech Connect

    Clarke, P.B.; Schwartz, R.D.; Paul, S.M.; Pert, C.B.; Pert, A.

    1985-05-01

    Three radioligands have been commonly used to label putative nicotinic cholinoceptors in the mammalian central nervous system: the agonists (/sup 3/H)nicotine and (/sup 3/H)acetylcholine ((/sup 3/H)ACh--in the presence of atropine to block muscarinic receptors), and the snake venom extract, (/sup 125/I)-alpha-bungarotoxin((/sup 125/I)BTX), which acts as a nicotinic antagonist at the neuromuscular junction. Binding studies employing brain homogenates indicate that the regional distributions of both (/sup 3/H)nicotine and (/sup 3/H)ACh differ from that of (/sup 125/I)BTX. The possible relationship between brain sites bound by (/sup 3/H)nicotine and (/sup 3/H)ACh has not been examined directly. The authors have used the technique of autoradiography to produce detailed maps of (/sup 3/H)nicotine, (/sup 3/H)ACh, and (/sup 125/I)BTX labeling; near-adjacent tissue sections were compared at many levels of the rat brain. The maps of high affinity agonist labeling are strikingly concordant, with highest densities in the interpeduncular nucleus, most thalamic nuclei, superior colliculus, medial habenula, presubiculum, cerebral cortex (layers I and III/IV), and the substantia nigra pars compacta/ventral tegmental area. The pattern of (/sup 125/I)BTX binding is strikingly different, the only notable overlap with agonist binding being the cerebral cortex (layer I) and superior colliculus. (/sup 125/I)BTX binding is also dense in the inferior colliculus, cerebral cortex (layer VI), hypothalamus, and hippocampus, but is virtually absent in thalamus. Various lines of evidence suggest that the high affinity agonist-binding sites in brain correspond to nicotinic cholinergic receptors similar to those found at autonomic ganglia; BTX-binding sites may also serve as receptors for nicotine and are possibly related to neuromuscular nicotinic cholinoceptors.

  18. Cortical laminar tau deposits and activated astrocytes in Alzheimer’s disease visualised by 3H-THK5117 and 3H-deprenyl autoradiography

    PubMed Central

    Lemoine, Laetitia; Saint-Aubert, Laure; Nennesmo, Inger; Gillberg, Per-Göran; Nordberg, Agneta

    2017-01-01

    Hyperphosphorylated tau protein deposits and, inflammatory processes are characteristic components of Alzheimer disease (AD) pathology. We here aimed to visualize in vitro the distribution of tau deposits and activated astrocytes across the cortical layers in autopsy AD brain tissue using the radiotracers 3H-THK5117 and 3H-deprenyl. 3H-THK5117 and 3H-deprenyl autoradiographies were carried out on frozen brain sections from three AD patients and one healthy control. 3H-THK5117 showed a distinct laminar cortical binding similar to 3H-deprenyl autoradiography, with an extensive binding in the superficial and deep layers of the temporal neocortices, whereas the middle frontal gyrus showed an even binding throughout the layers. Globally, eventhough some differences could be observed, AT8 (tau) and GFAP (astrocyte) immunostaining showed a laminar pattern comparable to their corresponding radiotracers within each AD case. Some variability was observed between the AD cases reflecting differences in disease phenotype. The similar laminar cortical brain distribution of tau deposits and activated astrocytes supports the hypothesis of a close pathological interconnection. The difference in regional binding patterns of 3H-THK5117 and AT8 antibody staining suggest additional tau binding sites detectable by 3H-THK5117. PMID:28374768

  19. Autoradiographic analysis of the in vivo distribution of 3H-imipramine and 3H-desipramine in brain: Comparison to in vitro binding patterns

    SciTech Connect

    Duncan, G.E.; Paul, I.A.; Fassberg, J.B.; Powell, K.R.; Stumpf, W.E.; Breese, G.R. )

    1991-03-01

    Using high resolution autoradiographic techniques, the distribution of radioactivity in forebrain and brainstem was assessed after 4 injection of 3H-impramine or 3H-desipramine. Results were compared with regional binding of the drugs to brain sections in vitro. Similar topographic binding of 3H-imipramine and 3H-desipramine was observed in vitro among brain regions, except in the paraventricular nucleus of the hypothalamus and locus coeruleus, where binding was greater for 3H-desipramine. For both 3H-desipramine and 3H-imipramine, some brain regions that exhibited high binding in vitro also showed high accumulation after in vivo injection. However, certain regions that contained high densities of binding sites for the antidepressant drugs as measured by in vitro binding showed very low accumulation of radioactivity after in vivo treatment. Such regions included the dentate gyrus of the hippocampus, layer 1 of piriform cortex, caudate-putamen, pontine and midbrain central gray, and cerebellar granular layer. Compared to in vitro binding of the drugs, the distribution of imipramine and desipramine in vivo appears more anatomically selective. For imipramine, primary sites of action in vivo, as indicated by the topographic distribution in brain, appear to be the locus coeruleus, hippocampus, lateral septal nucleus, and amygdala. For desipramine, the greatest accumulation in vivo was found in the locus coeruleus, paraventricular nucleus of the hypothalamus, and anterior thalamic nuclei.

  20. Localization of 3H-diethylstilbestrol in skeletal muscle

    SciTech Connect

    Gruber, B.; Cohen, L.

    1981-11-01

    The localization of diethylstilbestrol (DES) in skeletal muscle was studied in CF1 mice and perfused rat hindlimbs. There was a slow accumulation of 3H-DES in mouse muscle from 4 to 24 hours following i.p. injection even though plasma DES was decreasing. Twenty-four hours after injection of 50 microCi 3H-DES (714 pmole) mouse gastrocnemius contained 8.9 x 10(-17) mole unaltered 3H-DES per mg muscle. Extrapolating to the entire skeletal muscle mass of the animal, this represents 0.15% of the radioactivity injected. The radioactivity in muscle was completely extracted with 95% ethanol or ether: ethanol (3:1), and both unaltered DES and DES-metabolites were present in the extracts. The fraction of radioactivity due to unaltered DES 4 hours after injection was 0.51 +/- 0.09 in muscle and 0.30 +/- 0.11 in plasma. Significant extrahepatic metabolism of DES was demonstrated in perfused isolated rat hindlimbs by the presence of DES-metabolites in the perfusate. The radioactivity extracted from the perfused muscle itself was unaltered DES. These results indicate that skeletal muscle is an important site of DES localization in rodents.

  1. Mapping Region of Human Restriction Factor APOBEC3H Critical for Interaction with HIV-1 Vif.

    PubMed

    Nakashima, Masaaki; Tsuzuki, Shinya; Awazu, Hiroaki; Hamano, Akiko; Okada, Ayaka; Ode, Hirotaka; Maejima, Masami; Hachiya, Atsuko; Yokomaku, Yoshiyuki; Watanabe, Nobuhisa; Akari, Hirofumi; Iwatani, Yasumasa

    2017-03-21

    The APOBEC3 (A3) family of cellular cytidine deaminases comprises seven members (A, B, C, D, F, G, and H) that potently inhibit retroviral replication. Human immunodeficiency virus type 1 (HIV-1) Vif is a small pleiotropic protein that specifically inactivates these enzymes, targeting them for ubiquitin-mediated proteasomal degradation. A3 Vif-interaction sites are presumed to fall into three distinct types: A3C/D/F, A3G, and A3H. To date, two types of A3G and A3C/D/F sites have been well characterized, whereas the A3H Vif-binding site remains poorly defined. Here, we explore the residues critical for the A3H-type Vif interaction. To avoid technical difficulties in performing experiments with human A3H haplotype II (hapII), which is relatively resistant to HIV-1 Vif, we employed its ortholog chimpanzee A3H (cA3H), which displays high Vif sensitivity, for a comparison of sensitivity with that of A3H hapII. The Vif susceptibility of A3H hapII-cA3H chimeras and their substitution mutants revealed a single residue at position 97 as a major determinant for the difference in their Vif sensitivities. We further surveyed critical residues by structure-guided mutagenesis using an A3H structural model and thus identified eight additional residues important for Vif sensitivity, which mapped to the α3 and α4 helices of A3H. Interestingly, this area is located on a surface adjacent to the A3G and A3C/D/F interfaces and is composed of negatively charged and hydrophobic patches. These findings suggest that HIV-1 Vif has evolved to utilize three dispersed surfaces for recognizing three types of interfaces on A3 proteins under certain structural constraints.

  2. Significance of skeletal muscle digitalis receptors for [3H]ouabain distribution in the guinea pig.

    PubMed

    Kjeldsen, K; Nørgaard, A; Hansen, O; Clausen, T

    1985-09-01

    The importance of specific digitalis glycoside binding sites in skeletal muscle for the digitalis glycoside distribution in the guinea pig was evaluated using [3H]ouabain and [3H]digoxin binding assays. Measurements of [3H]ouabain binding capacity (EOmax) in gastrocnemius and heart muscles in vitro gave values of 474 +/- 15 and 1,092 +/- 39 pmol/g wet wt., respectively, in 4-week-old guinea pigs. Hence the total amount of [3H]ouabain binding sites in skeletal muscle and the heart was around 42,700 and 1,200 pmol, respectively. The apparent dissociation constants (Kd) for ouabain receptor interaction was 0.7 X 10(-7) and 1.5 X 10(-7) M for skeletal muscle and heart, respectively. Comparison of [3H]ouabain and [3H]digoxin binding revealed that these drugs are competitive. From birth to maturity the concentration of [3H]ouabain binding sites in guinea pigs decreased from 803 +/- 58 to 304 +/- 28 pmol/g wet wt. in gastrocnemius muscle and from 1,458 +/- 31 to 1,079 +/- 19 pmol/g wet wt. in the heart. After i.p. injection, measurements of the distribution of [3H]ouabain in plasma, skeletal muscle and the heart showed an almost equal relative specific occupancy of digitalis glycoside receptors in skeletal muscle and the heart: When 10% of the digitalis receptors in the heart were occupied by [3H]ouabain, 13% of those in the skeletal muscles were occupied. It was calculated that 1 hr after the i.p. administration of [3H]ouabain the amount of [3H]ouabain specifically bound to the skeletal muscles and the heart corresponded to 5 times and 1/10 the amount available in the extracellular pool, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

  3. Sr{sub 2}CaW{sub x}Mo{sub 1−x}O{sub 6}:Eu{sup 3+}, Li{sup +}: An emission tunable phosphor through site symmetry and excitation wavelength

    SciTech Connect

    Xiao, Ning; Shen, Jun; Xiao, Tengjiao; Wu, Bing; Luo, Xiaobing; Li, Li; Wang, Zhongqing; Zhou, Xianju

    2015-10-15

    The emission of Eu{sup 3+} doped Sr{sub 2}CaW{sub x}Mo{sub 1−x}O{sub 6} phosphors could be tunable by the site symmetry of the activators and the excitation wavelengths. - Highlights: • The emission of Eu{sup 3+} depends on site symmetry and excitation wavelengths. • The color of the samples was tunable by structure and excitation wavelength. • The effect of W and Eu content on the properties of the samples was investigated. - Abstract: A series of Eu{sup 3+} substituted double-perovskite Sr{sub 2}CaW{sub x}Mo{sub 1−x}O{sub 6} phosphors were prepared by solid state reactions. The phase, photoluminescence and energy transfer of the phosphors were investigated by X-ray diffraction (XRD), photoluminescence (PL) and luminescence decay respectively. It is found that the emission of the Eu{sup 3+} substituted double perovskites depends on both the site symmetry of the activators and the excitation wavelengths. Based on the decay analysis of Sr{sub 2}CaW{sub x}Mo{sub 1−x}O{sub 6} matrix and Eu{sup 3+} doped samples, the energy transfer efficiencies between the host and activators Eu{sup 3+} were investigated. The results of the emission tunable phosphors indicate their potential applications in LEDs.

  4. Broken Symmetry

    ScienceCinema

    None

    2016-07-12

    - Physics, as we know it, attempts to interpret the diverse natural phenomena as particular manifestations of general laws. This vision of a world ruled by general testable laws is relatively recent in the history of mankind. Basically it was initiated by the Galilean inertial principle. The subsequent rapid development of large-scale physics is certainly tributary to the fact that gravitational and electromagnetic forces are long-range and hence can be perceived directly without the mediation of highly sophisticated technical devices. - The discovery of subatomic structures and of the concomitant weak and strong short-range forces raised the question of how to cope with short-range forces in relativistic quantum field theory. The Fermi theory of weak interactions, formulated in terms of point-like current-current interaction, was well-defined in lowest order perturbation theory and accounted for existing experimental data.However, it was inconsistent in higher orders because of uncontrollable divergent quantum fluctuations. In technical terms, in contradistinction to quantum electrodynamics, the Fermi theorywas not “renormalizable”. This difficulty could not be solved by smoothing the point-like interaction by a massive, and therefore short-range, charged “vector” particle exchange: theories with massive charged vector bosons were not renormalizable either. In the early nineteen sixties, there seemed to be insuperable obstacles to formulating a consistent theory with short-range forces mediated by massive vectors. - The breakthrough came from the notion of spontaneous symmetry breaking which arose in the study of phase transitions and was introduced in field theory by Nambu in 1960. - Ferromagnets illustrate the notion in phase transitions. Although no direction is dynamically preferred, the magnetization selects a global orientation. This is a spontaneous broken symmetry(SBS)of rotational invariance. Such continuous SBS imply the existence of

  5. Broken Symmetry

    SciTech Connect

    2011-02-24

    - Physics, as we know it, attempts to interpret the diverse natural phenomena as particular manifestations of general laws. This vision of a world ruled by general testable laws is relatively recent in the history of mankind. Basically it was initiated by the Galilean inertial principle. The subsequent rapid development of large-scale physics is certainly tributary to the fact that gravitational and electromagnetic forces are long-range and hence can be perceived directly without the mediation of highly sophisticated technical devices. - The discovery of subatomic structures and of the concomitant weak and strong short-range forces raised the question of how to cope with short-range forces in relativistic quantum field theory. The Fermi theory of weak interactions, formulated in terms of point-like current-current interaction, was well-defined in lowest order perturbation theory and accounted for existing experimental data.However, it was inconsistent in higher orders because of uncontrollable divergent quantum fluctuations. In technical terms, in contradistinction to quantum electrodynamics, the Fermi theorywas not “renormalizable”. This difficulty could not be solved by smoothing the point-like interaction by a massive, and therefore short-range, charged “vector” particle exchange: theories with massive charged vector bosons were not renormalizable either. In the early nineteen sixties, there seemed to be insuperable obstacles to formulating a consistent theory with short-range forces mediated by massive vectors. - The breakthrough came from the notion of spontaneous symmetry breaking which arose in the study of phase transitions and was introduced in field theory by Nambu in 1960. - Ferromagnets illustrate the notion in phase transitions. Although no direction is dynamically preferred, the magnetization selects a global orientation. This is a spontaneous broken symmetry(SBS)of rotational invariance. Such continuous SBS imply the existence of

  6. Low-lying states of Li 3H: Is there an ion-pair minimum?

    NASA Astrophysics Data System (ADS)

    Talbi, Dahbia; Saxon, Roberta P.

    1989-05-01

    The 1 1A', 1 1A″, 1 3A', and 1 3A″ states of Li 3H have been investigated at the MCSCF/SOCI level. The global minimum is a planar conformation of 1A' symmetry. A local minimum on the same potential surface at a C 3v pyramidal geometry, of mixed ion-pair and covalent character, is found at a relative energy of 20.30 kcal/mol. The barrier height for isomerization is predicted to be 1.3 kcal/mol. The correlation diagram linking states of Li 3H to those of Li 3 + H, LiH + Li 2 and Li 2H + Li is presented.

  7. Translational Symmetry and Microscopic Constraints on Symmetry-Enriched Topological Phases: A View from the Surface

    NASA Astrophysics Data System (ADS)

    Cheng, Meng; Zaletel, Michael; Barkeshli, Maissam; Vishwanath, Ashvin; Bonderson, Parsa

    2016-10-01

    The Lieb-Schultz-Mattis theorem and its higher-dimensional generalizations by Oshikawa and Hastings require that translationally invariant 2D spin systems with a half-integer spin per unit cell must either have a continuum of low energy excitations, spontaneously break some symmetries, or exhibit topological order with anyonic excitations. We establish a connection between these constraints and a remarkably similar set of constraints at the surface of a 3D interacting topological insulator. This, combined with recent work on symmetry-enriched topological phases with on-site unitary symmetries, enables us to develop a framework for understanding the structure of symmetry-enriched topological phases with both translational and on-site unitary symmetries, including the effective theory of symmetry defects. This framework places stringent constraints on the possible types of symmetry fractionalization that can occur in 2D systems whose unit cell contains fractional spin, fractional charge, or a projective representation of the symmetry group. As a concrete application, we determine when a topological phase must possess a "spinon" excitation, even in cases when spin rotational invariance is broken down to a discrete subgroup by the crystal structure. We also describe the phenomena of "anyonic spin-orbit coupling," which may arise from the interplay of translational and on-site symmetries. These include the possibility of on-site symmetry defect branch lines carrying topological charge per unit length and lattice dislocations inducing degeneracies protected by on-site symmetry.

  8. Binding of (/sup 3/H)forskolin to solubilized preparations of adenylate cyclase

    SciTech Connect

    Nelson, C.A.; Seamon, K.B.

    1988-01-01

    The binding of (/sup 3/H)forskolin to proteins solubilized from bovine brain membranes was studied by precipitating proteins with polyethylene glycol and separating (/sup 3/H)forskolin bound to protein from free (/sup 3/H)forskolin by rapid filtration. The K/sub d/ for (/sup 3/H)forskolin binding to solubilized proteins was 14 nM which was similar to that for (/sup 3/H)forskolin binding sites in membranes from rat brain and human platelets. Forskolin analogs competed for (/sup 3/H)forskolin binding sites with the same rank potency in both brain membranes and in proteins solubilized from brain membranes. (/sup 3/H)forskolin bound to proteins solubilized from membranes with a Bmax of 38 fmolmg protein which increased to 94 fmolmg protein when GppNHp was included in the binding assay. In contrast, GppNHp had no effect on (/sup 3/H)forskolin binding to proteins solubilized from membranes preactivated with GppNHp. Solubilized adenylate cyclase from non-preactivated membranes had a basal activity of 130 pmolmgmin which was increased 7-fold by GppNHp. In contrast, adenylate cyclase from preactivated membranes had a basal activity of 850 pmolmgmin which was not stimulated by GppNHp or forskolin

  9. Continuous symmetry measures for complex symmetry group.

    PubMed

    Dryzun, Chaim

    2014-04-05

    Symmetry is a fundamental property of nature, used extensively in physics, chemistry, and biology. The Continuous symmetry measures (CSM) is a method for estimating the deviation of a given system from having a certain perfect symmetry, which enables us to formulate quantitative relation between symmetry and other physical properties. Analytical procedures for calculating the CSM of all simple cyclic point groups are available for several years. Here, we present a methodology for calculating the CSM of any complex point group, including the dihedral, tetrahedral, octahedral, and icosahedral symmetry groups. We present the method and analyze its performances and errors. We also introduce an analytical method for calculating the CSM of the linear symmetry groups. As an example, we apply these methods for examining the symmetry of water, the symmetry maps of AB4 complexes, and the symmetry of several Lennard-Jones clusters.

  10. The Structural Interface between HIV-1 Vif and Human APOBEC3H.

    PubMed

    Ooms, Marcel; Letko, Michael; Simon, Viviana

    2017-03-01

    Human APOBEC3H (A3H) is a cytidine deaminase that inhibits HIV-1 replication. To evade this restriction, the HIV-1 Vif protein binds A3H and mediates its proteasomal degradation. To date, little information on the Vif-A3H interface has been available. To decipher how both proteins interact, we first mapped the Vif-binding site on A3H by functionally testing a large set of A3H mutants in single-cycle infectivity and replication assays. Our data show that the two A3H α-helixes α3 and α4 represent the Vif-binding site of A3H. We next used viral adaptation and a set of Vif mutants to identify novel, reciprocal Vif variants that rescued viral infectivity in the presence of two Vif-resistant A3H mutants. These A3H-Vif interaction points were used to generate the first A3H-Vif structure model, which revealed that the A3H helixes α3 and α4 interact with the Vif β-sheet (β2-β5). This model is in good agreement with previously reported Vif and A3H amino acids important for interaction. Based on the predicted A3H-Vif interface, we tested additional points of contact, which validated our model. Moreover, these experiments showed that the A3H and A3G binding sites on HIV-1 Vif are largely distinct, with both host proteins interacting with Vif β-strand 2. Taken together, this virus-host interface model explains previously reported data and will help to identify novel drug targets to combat HIV-1 infection.IMPORTANCE HIV-1 needs to overcome several intracellular restriction factors in order to replicate efficiently. The human APOBEC3 locus encodes seven proteins, of which A3D, A3F, A3G, and A3H restrict HIV-1. HIV encodes the Vif protein, which binds to the APOBEC3 proteins and leads to their proteasomal degradation. No HIV-1 Vif-APOBEC3 costructure exists to date despite extensive research. We and others previously generated HIV-1 Vif costructure models with A3G and A3F by mapping specific contact points between both proteins. Here, we applied a similar approach to HIV

  11. Alpha 2 adrenergic receptors in hyperplastic human prostate: identification and characterization using (/sup 3/H) rauwolscine

    SciTech Connect

    Shapiro, E.; Lepor, H.

    1986-05-01

    (/sup 3/H)Rauwolscine ((/sup 3/H)Ra), a selective ligand for the alpha 2 adrenergic receptor, was used to identify and characterize alpha 2 adrenergic receptors in prostate glands of men with benign prostatic hyperplasia. Specific binding of (/sup 3/H)Ra to prostatic tissue homogenates was rapid and readily reversible by addition of excess unlabelled phentolamine. Scatchard analysis of saturation experiments demonstrates a single, saturable class of high affinity binding sites (Bmax = 0.31 +/- 0.04 fmol./microgram. DNA, Kd = 0.9 +/- 0.11 nM.). The relative potency of alpha adrenergic drugs (clonidine, alpha-methylnorepinephrine and prazosin) in competing for (/sup 3/H)Ra binding sites was consistent with the order predicted for an alpha 2 subtype. The role of alpha 2 adrenergic receptors in normal prostatic function and in men with bladder outlet obstruction secondary to BPH requires further investigation.

  12. Correlation between (/sup 3/H)dopamine specific uptake and (/sup 3/H)GBR 12783 specific binding during the maturation of rat striatum

    SciTech Connect

    Bonnet, J.J.; Costentin, J.

    1989-01-01

    The development of the specific uptake of dopamine in the rat striatum during the early postnatal period is compared with the ontogenetic changes of the specific binding of (/sup 3/H)GBR 12783 to the site of uptake inhibition. During maturation, the increase in the specific binding of (/sup 3/H)GBR 12783 parallels the increase in the specific uptake of dopamine. (/sup 3/H)GBR 12783 specific binding sites increase in number from day 1 postpartum until 40 days, when they reach the adult level. In 40 day-old rats, the weight of the striatum represents 80% of adult values. The affinity of (/sup 3/H)GBR 12783 for the inhibition site is similar in membrane preparations obtained from 6 day-old pups and adults; this results in a same ability of the inhibitor to block the specific uptake of dopamine into synaptosomes obtained from pups or adult rats. These data support the hypothesis of the existence of a single molecular entity including both the inhibition site and the carrier itself.

  13. Photoaffinity labeling of the dopamine reuptake carrier protein with 3-azido sup 3 H GBR-12935

    SciTech Connect

    Berger, S.P.; Martenson, R.E.; Laing, P.; Thurkauf, A.; Decosta, B.; Rice, K.C.; Paul, S.M. )

    1991-04-01

    A high affinity tritiated azido-diphenylpiperazine derivative, 3-azido {sup 3}H GBR-12935, was synthesized as a potential photoaffinity probe of the dopamine transporter. Initially, the reversible binding of 3-azido {sup 3}H GBR-12935 to crude synaptosomal membranes from the rat striatum was characterized. Specific binding was sodium dependent and inhibited by a variety of drugs that are known to potently inhibit dopamine uptake. Other neurotransmitter uptake inhibitors, as well as cis-flupenthixol, a potent inhibitor of {sup 3}H GBR-12935 binding to piperazine binding sites, failed to inhibit specific binding at concentrations of less than or equal to 10 microM. A good correlation was observed between the relative potencies of these drugs in inhibiting dopamine uptake into synaptosomes and in inhibiting specific 3-azido {sup 3}H GBR-12935 binding to rat striatal membranes. These data suggest that 3-azido {sup 3}H GBR-12935, like other diphenylpiperazines such as {sup 3}H GBR-12935 and {sup 3}H GBR-12909, binds primarily to the dopamine transporter under defined assay conditions. After UV photolysis of crude synaptosomal membranes preincubated with 3-azido {sup 3}H GBR-12935 (1-2 nM), a single radiolabeled polypeptide with an apparent molecular mass of 80 kDa was observed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and fluorography. Photoincorporation of 3-azido {sup 3}H GBR-12935 into this polypeptide was inhibited selectively by compounds that inhibit the uptake of dopamine and was completely dependent on the presence of Na+. No photolabeled proteins were observed when cerebellar membranes were substituted for striatal membranes. Essentially complete adsorption of the radiolabeled 80-kDa polypeptide to wheat germ agglutinin and elution with N-acetyl-D-glucosamine strongly suggest that the dopamine transporter polypeptide photolabeled by 3-azido {sup 3}H GBR-12935 is glycosylated.

  14. [3H]-verapamil binding to rat cardiac sarcolemmal membrane fragments; an effect of ischaemia.

    PubMed Central

    Dillon, J. S.; Nayler, W. G.

    1987-01-01

    The [3H]-verapamil binding activity of rat cardiac sarcolemmal fragments was studied, using membranes harvested from non-perfused, aerobically-perfused and ischaemic hearts. Glass-fibre filters were found to contain specific, high affinity--(KD 38 +/- 3.1 nM) [3H]-verapamil binding sites--making them unsuitable for use in [3H]-verapamil binding studies. Incubation of membranes from non-perfused hearts in a medium containing 150 mM NaCl, 1 mM CaCl2 and 50 mM Tris revealed two populations of [3H]-verapamil binding sites. When centrifugation instead of filtration was used to separate bound and free [3H]-verapamil, high affinity sites with a KD of 0.57 +/- 0.19 microM and a Bmax of 38 +/- 5.2 pmol mg-1 protein, and low affinity sites with a KD of 78 +/- 27.5 microM and a Bmax of 2.9 +/- 1.3 nmol mg-1 protein were detected. However, only low affinity binding sites could be detected in membranes which had been incubated in a cation-free medium containing 50 mM Tris. [3H]-verapamil binding to the low and high affinity sites was saturable, reversible, stereospecific and displaceable by D600 greater than diltiazem greater than Ca2+ but not by nifedipine, nitrendipine, nisoldipine or prazosin. The two populations of binding sites survived aerobic perfusion and 60 min ischaemia at 37 degrees C. Ischaemia reduced the Bmax and KD but selectivity was maintained. PMID:3028561

  15. Concomitant Ordering and Symmetry Lowering

    ERIC Educational Resources Information Center

    Boo, William O. J.; Mattern, Daniell L.

    2008-01-01

    Examples of concomitant ordering include magnetic ordering, Jahn-Teller cooperative ordering, electronic ordering, ionic ordering, and ordering of partially-filled sites. Concomitant ordering sets in when a crystal is cooled and always lowers the degree of symmetry of the crystal. Concomitant ordering concepts can also be productively applied to…

  16. Relativistic Pseudospin Symmetry

    SciTech Connect

    Ginocchio, Joseph N.

    2011-05-06

    We show that the pseudospin symmetry that Akito Arima discovered many years ago (with collaborators) is a symmetry of the the Dirac Hamiltonian for which the sum of the scalar and vector potentials are a constant. In this paper we discuss some of the implications of this relativistic symmetry and the experimental data that support these predictions. In his original paper Akito also discussed pseudo-U(3) symmetry. We show that pseudo-U(3) symmetry is a symmetry of the Dirac Hamiltonian for which the sum of harmonic oscillator vector and scalar potentials are equal to a constant, and we give the generators of pseudo-U(3) symmetry. Going beyond the mean field we summarize new results on non relativistic shell model Hamiltonians that have pseudospin symmetry and pseudo-orbital angular momentum symmetry as a dynamical symmetries.

  17. Studies with the high-affinity antiestrogen, (/sup 3/H)HI285

    SciTech Connect

    Keene, J.L.

    1985-01-01

    Antiestrogens are compounds that inhibit some of the actions of estrogens. Certain antiestrogens, notably the triphenylethylene, tamoxifen, are useful in the treatment of female breast cancer. The triphenylethylene antiestrogen, HI285, was labelled with radioactive hydrogen ((/sup 3/H)) for use as a probe of antiestrogen action. Radioactive HI285 ((/sup 3/H)HI285) bound to the cytosolic estrogen receptor from both rat and calf uterus and competed with estradiol for the estrogen specific binding site. In both animals (/sup 3/H)HI285 displayed a higher affinity for the estrogen receptor and a slower dissociation rate from the receptor than did estradiol. (/sup 3/H)HI285, as well as estradiol, appeared to trigger receptor activation. Studies using the activation blocker, sodium molybdate, indicated that (/sup 3/H)HI285 triggered activation in a manner different from estradiol. The non-activated estrogen receptor from calf uterus, when occupied by (/sup 3/H)estradiol, existed as two discrete forms that could be separated by ion-exchange chromatography. In contrast, the (/sup 3/H)HI285-occupied receptor existed as a single form.

  18. Study of the docking of competitive inhibitors at a model of tyrosinase active site: insights from joint broken-symmetry/Spin-Flip DFT computations and ELF topological analysis

    PubMed Central

    de la Lande, A.; Maddaluno, J.; Parisel, O.; Darden, T. A.; Piquemal, J-P

    2010-01-01

    Following our previous study (Piquemal et al., New J. Chem., 2003, 27, 909), we present here a DFT study of the inhibition of the Tyrosinase enzyme. Broken-symmetry DFT computations are supplemented with Spin-Flip TD-DFT calculations, which, for the first time, are applied to such a dicopper enzyme. The chosen biomimetic model encompasses a dioxygen molecule, two Cu(II) cations, and six imidazole rings. The docking energy of a natural substrate, namely phenolate, together with those of several inhibitor and non-inhibitor compounds, are reported and show the ability of the model to rank the most potent inhibitors in agreement with experimental data. With respect to broken-symmetry calculations, the Spin-Flip TD-DFT approach reinforces the possibility for theory to point out potent inhibitors: the need for the deprotonation of the substrates, natural or inhibitors, is now clearly established. Moreover, Electron Localization Function (ELF) topological analysis computations are used to deeply track the particular electronic distribution of the Cu-O-Cu three-center bonds involved in the enzymatic Cu2O2 metallic core (Piquemal and Pilmé, J. Mol. Struct.: Theochem, 2006, 77, 764). It is shown that such bonds exhibit very resilient out-of-plane density expansions that play a key role in docking interactions: their 3D-orientation could be the topological electronic signature of oxygen activation within such systems. PMID:20396590

  19. Study of the docking of competitive inhibitors at a model of tyrosinase active site: insights from joint broken-symmetry/Spin-Flip DFT computations and ELF topological analysis.

    PubMed

    de la Lande, A; Maddaluno, J; Parisel, O; Darden, T A; Piquemal, J-P

    2010-03-01

    Following our previous study (Piquemal et al., New J. Chem., 2003, 27, 909), we present here a DFT study of the inhibition of the Tyrosinase enzyme. Broken-symmetry DFT computations are supplemented with Spin-Flip TD-DFT calculations, which, for the first time, are applied to such a dicopper enzyme. The chosen biomimetic model encompasses a dioxygen molecule, two Cu(II) cations, and six imidazole rings. The docking energy of a natural substrate, namely phenolate, together with those of several inhibitor and non-inhibitor compounds, are reported and show the ability of the model to rank the most potent inhibitors in agreement with experimental data. With respect to broken-symmetry calculations, the Spin-Flip TD-DFT approach reinforces the possibility for theory to point out potent inhibitors: the need for the deprotonation of the substrates, natural or inhibitors, is now clearly established. Moreover, Electron Localization Function (ELF) topological analysis computations are used to deeply track the particular electronic distribution of the Cu-O-Cu three-center bonds involved in the enzymatic Cu(2)O(2) metallic core (Piquemal and Pilmé, J. Mol. Struct.: Theochem, 2006, 77, 764). It is shown that such bonds exhibit very resilient out-of-plane density expansions that play a key role in docking interactions: their 3D-orientation could be the topological electronic signature of oxygen activation within such systems.

  20. Revealing the Cu(2+) ions localization at low symmetry Bi sites in photorefractive Bi12GeO20 crystals doped with Cu and V by high frequency EPR.

    PubMed

    Nistor, Sergiu V; Stefan, Mariana; Goovaerts, Etienne; Ramaz, François; Briat, Bernard

    2015-10-01

    The sites of incorporation of Cu(2+) impurity ions in Bi12GeO20 single crystals co-doped with copper and vanadium have been investigated by electron paramagnetic resonance (EPR). While the X-band EPR spectra consist of a simple broad (ΔB ∼50 mT) line with anisotropic lineshape, the W-band EPR spectra exhibit well resolved, strongly anisotropic lines, due to transitions within the 3d(9)-(2)D ground manifold of the Cu(2+) ions. The most intense group of lines, attributed to the dominant Cu(2+)(I) center, displays a characteristic four components hyperfine structure for magnetic field orientations close to a 〈110〉 direction. The g and A tensor main axes are very close to one of the 12 possible sets of orthogonal 〈1-10〉, 〈00-1〉 and 〈110〉 crystal directions. Several less intense lines, with unresolved hyperfine structure and similar symmetry properties, mostly overlapped by the Cu(2+)(I) spectrum, were attributed to Cu(2+)(II) centers. The two paramagnetic centers are identified as substitutional Cu(2+) ions at Bi(3+) sites with low C1 symmetry, very likely resulting from different configurations of neighboring charge compensating defects.

  1. Inhibition of brain [(3)H]cimetidine binding by improgan-like antinociceptive drugs.

    PubMed

    Stadel, Rebecca; Carpenter, Amanda B; Nalwalk, Julia W; de Esch, Iwan J P; Janssen, Elwin; Hough, Lindsay B

    2010-04-25

    [(3)H]cimetidine, a radiolabeled histamine H(2) receptor antagonist, binds with high affinity to an unknown hemoprotein in the brain which is not the histamine H(2) receptor. Improgan, a close chemical congener of cimetidine, is a highly effective pain-relieving drug following CNS administration, yet its mechanism of action remains unknown. To test the hypothesis that the [(3)H]cimetidine-binding site is the improgan antinociceptive target, improgan, cimetidine, and 8 other chemical congeners were studied as potential inhibitors of [(3)H]cimetidine binding in membrane fractions from the rat brain. All compounds produced a concentration-dependent inhibition of [(3)H]cimetidine binding over a 500-fold range of potencies (K(i) values were 14.5 to >8000nM). However, antinociceptive potencies in rats did not significantly correlate with [(3)H]cimetidine-binding affinities (r=0.018, p=0.97, n=10). These results suggest that the [(3)H]cimetidine-binding site is not the analgesic target for improgan-like drugs.

  2. Endocytic pathway for /sup 3/H-histamine (/sup 3/H-HIS) metabolism in cultured human vascular endothelial cells (HEC)

    SciTech Connect

    Haddock, R.C.; Mack, P.; Baenziger, N.L.

    1986-03-01

    Histamine metabolism by HEC utilizes enzymes from both endogenous and extracellular sources. HEC convert histamine to tele-methyl-histamine and accumulate this product. They exhibit a 6- to 10-fold enhancement of /sup 3/H-HIS uptake by exogenous amine oxidase activity from human placenta (P-AO) or fetal calf serum (FCS-AO) and accumulate methyl-imidazole-acetic acid (MIAA). /sup 3/H-HIS uptake is saturable with respect to /sup 3/H-HIS and to P-AO or FCS-AO, suggesting a limited number of interaction sites on HEC. Half maximal and saturated uptake occur at 1.6 ..mu..M and 4 ..mu..M for /sup 3/H-HIS, at 0.14 U/ml and 0.65 U/ml for P-AO, and 1.0- U/ml and 2.0 U/ml for FCS-AO (1 U/ml = 1 nmole putrescine degraded/hour). FCS-AO-enhanced uptake is inhibited 64% to 94% by 3-30 mM methylmaine and 98% by 75 ..mu..M chloroquine. Treatment of HEC with dextran sulfate removes bound FCS-AO activity, blocking subsequent /sup 3/H-HIS uptake by 84%. /sup 3/H-HIS-derived metabolites present in the plasma membrane fraction of HEC incubated in the absence or presence of FCS-AO activity, are tele-methyl-histamine or MIAA respectively. These results suggest the involvement of an endocytic-type process in /sup 3/H-HIS uptake and degradation, utilizing membrane-associated endogenous and exogenous enzymes.

  3. Binding of (/sup 3/H)forskolin to platelet membranes and solubilized proteins from bovine brain

    SciTech Connect

    Nelson, C.A.; Seamon, K.B.

    1986-05-01

    (/sup 3/H)Forskolin ((/sup 3/H)FSK) bound to platelet membranes with a Kd of 20 nM and a Bmax of 125 fmol/mg protein. The Bmax was increased to 400 fmol/mg protein in the presence of GppNHp (or NaF) and MgCl/sub 2/ with no change in Kd. PGE/sub 1/ decreased the EC50 of GppNHp to increase the Bmax for (/sup 3/H)FSK binding from 600 nM to 35 nM. In contrast, PGE/sub 1/ had no effect on the EC50 of NaF to increase (/sup 3/H)FSK binding. (/sup 3/H)FSK binding increased slowly over 60 min when forskolin and GppNHp were added to membranes simultaneously at 20/sup 0/C. Preincubation of membranes with GppNHp at 20/sup 5/C also caused a linear increase in adenylate cyclase specific activity over 60 minutes. (/sup 3/H)FSK bound to solubilized protein from bovine brain membrane with a Kd of 22 nM. GppNHp increased the number of binding sites in solubilized proteins only if membranes were not preincubated with GppNHp prior to solubilization. In conclusion the number of binding sites for (/sup 3/H)FSK is increased by agents that activate adenylate cyclase through the Ns protein. These sites appear to be associated with an activated complex of the Ns protein and adenylate cyclase.

  4. Symmetries in Physics

    NASA Astrophysics Data System (ADS)

    Brading, Katherine; Castellani, Elena

    2010-01-01

    Preface; Copyright acknowledgements; List of contributors; 1. Introduction; Part I. Continuous Symmetries: 2. Classic texts: extracts from Weyl and Wigner; 3. Review paper: On the significance of continuous symmetry to the foundations of physics C. Martin; 4. The philosophical roots of the gauge principle: Weyl and transcendental phenomenological idealism T. Ryckman; 5. Symmetries and Noether's theorems K. A. Brading and H. R. Brown; 6. General covariance, gauge theories, and the Kretschmann objection J. Norton; 7. The interpretation of gauge symmetry M. Redhead; 8. Tracking down gauge: an ode to the constrained Hamiltonian formalism J. Earman; 9. Time-dependent symmetries: the link between gauge symmetries and indeterminism D. Wallace; 10. A fourth way to the Aharanov-Bohm effect A. Nounou; Part II. Discrete Symmetries: 11. Classic texts: extracts from Lebniz, Kant and Black; 12. Review paper: Understanding permutation symmetry S. French and D. Rickles; 13. Quarticles and the identity of discernibles N. Hugget; 14. Review paper: Handedness, parity violation, and the reality of space O. Pooley; 15. Mirror symmetry: what is it for a relational space to be orientable? N. Huggett; 16. Physics and Leibniz's principles S. Saunders; Part III. Symmetry Breaking: 17: Classic texts: extracts from Curie and Weyl; 18. Extract from G. Jona-Lasinio: Cross-fertilization in theoretical physics: the case of condensed matter and particle physics G. Jona-Lasinio; 19. Review paper: On the meaning of symmetry breaking E. Castellani; 20. Rough guide to spontaneous symmetry breaking J. Earman; 21. Spontaneous symmetry breaking: theoretical arguments and philosophical problems M. Morrison; Part IV. General Interpretative Issues: 22. Classic texts: extracts from Wigner; 23. Symmetry as a guide to superfluous theoretical structure J. Ismael and B. van Fraassen; 24. Notes on symmetries G. Belot; 25. Symmetry, objectivity, and design P. Kosso; 26. Symmetry and equivalence E. Castellani.

  5. Effects of delta9-THC on the synaptosomal uptake of 3H-tryptophan and 3H-choline.

    PubMed

    Johnson, K M; Dewey, W L

    1978-01-01

    The in vitro addition of (-)-delta9-tetrahydrocannabinol (delta9-THC) resulted in a dose-responsive inhibition of the high-affinity specific synaptosomal uptake of both 3H-tryptophan and 3H-choline in mouse forebrain crude synaptosomal preparations. The approximate concentrations of delta9-THC required to cause a 50% inhibition of the uptake of 3H-tryptophan and 3H-choline were 33 and 16 muM, respectively. Kinetic analysis showed that inhibition of both compounds were consistent with a noncompetitive mechanism. The pretreatment of mice with doses of 10, 30 or 100 mg/kg delta9-THC had no effect on the subsequent in vitro synaptosomal uptake of either 3H-tryptophan or 3H-choline into forebrain synaptosomes.

  6. Approximate flavor symmetries

    SciTech Connect

    Rasin, A.

    1994-04-01

    We discuss the idea of approximate flavor symmetries. Relations between approximate flavor symmetries and natural flavor conservation and democracy models is explored. Implications for neutrino physics are also discussed.

  7. Autoradiographic Localization of [3H]Gentamicin in the Proximal Renal Tubules of Mice

    PubMed Central

    Kuhar, Michael J.; Mak, Linda L.; Lietman, Paul S.

    1979-01-01

    The site of localization of [3H]gentamicin within mouse kidney is shown to be the proximal renal tubule by coincidence of the radioactivity, as visualized by autoradiography, and the mucopolysaccharide-rich microvilli characteristic of proximal convoluted tubules, as visualized by histochemical staining. Images PMID:426500

  8. Neutrinos and flavor symmetries

    SciTech Connect

    Tanimoto, Morimitsu

    2015-07-15

    We discuss the recent progress of flavor models with the non-Abelian discrete symmetry in the lepton sector focusing on the θ{sub 13} and CP violating phase. In both direct approach and indirect approach of the flavor symmetry, the non-vanishing θ{sub 13} is predictable. The flavor symmetry with the generalised CP symmetry can also predicts the CP violating phase. We show the phenomenological analyses of neutrino mixing for the typical flavor models.

  9. Synthetic studies towards putative yuremamine using an iterative C(sp(3))-H arylation strategy.

    PubMed

    Calvert, Matthew B; Sperry, Jonathan

    2016-06-28

    An overview of an iterative, 8-aminoquinoline (AQ)-directed C(sp(3))-H arylation strategy towards the pyrroloindole structure initially assigned to the alkaloid yuremamine is described. During initial efforts using a model indane system, it was discovered that the iodoresorcinol unit was not a viable C(sp(3))-H arylation partner when masked as its dimethyl ether but upon switching to a MOM group, the ether oxygen served to stabilise the high valent Pd intermediate during the reaction, thus promoting reductive elimination and leading to acceptable yields of the C(sp(3))-H arylation product. The second C(sp(3))-H arylation with an iodopyrogallol gave a 1,3-diarylated model yuremamine system possessing the desired 1,3-cis relationship. When the successful model studies were applied to a pyrroloindole system in pursuit of yuremamine, it became apparent that C9 underwent competing C(sp(2))-H arylation if left vacant, but installing a tryptamine side chain at this site prevented the desired C(sp(3))-H arylation from occurring altogether. However, a C9-methyl pyrroloindole underwent iterative C(sp(3))-H arylation at C1 with an iodoresorcinol followed by C3 with an iodopyrogallol to give a diarylated product with the aryl groups in the undesired 1,3-trans-relationship, arising from epimerisation at C1 during the second C(sp(3))-H arylation event. Although the synthesis of putative yuremamine was not accomplished, several findings are disclosed that will serve as useful additions to the burgeoning field of directed C(sp(3))-H arylations and related C-H functionalization reactions.

  10. Polynomial Graphs and Symmetry

    ERIC Educational Resources Information Center

    Goehle, Geoff; Kobayashi, Mitsuo

    2013-01-01

    Most quadratic functions are not even, but every parabola has symmetry with respect to some vertical line. Similarly, every cubic has rotational symmetry with respect to some point, though most cubics are not odd. We show that every polynomial has at most one point of symmetry and give conditions under which the polynomial has rotational or…

  11. Chiral symmetry and chiral-symmetry breaking

    SciTech Connect

    Peskin, M.E.

    1982-12-01

    These lectures concern the dynamics of fermions in strong interaction with gauge fields. Systems of fermions coupled by gauge forces have a very rich structure of global symmetries, which are called chiral symmetries. These lectures will focus on the realization of chiral symmetries and the causes and consequences of thier spontaneous breaking. A brief introduction to the basic formalism and concepts of chiral symmetry breaking is given, then some explicit calculations of chiral symmetry breaking in gauge theories are given, treating first parity-invariant and then chiral models. These calculations are meant to be illustrative rather than accurate; they make use of unjustified mathematical approximations which serve to make the physics more clear. Some formal constraints on chiral symmetry breaking are discussed which illuminate and extend the results of our more explicit analysis. Finally, a brief review of the phenomenological theory of chiral symmetry breaking is presented, and some applications of this theory to problems in weak-interaction physics are discussed. (WHK)

  12. Polarized Raman study of [N(C3H7)4]2Cd2Cl6 single crystal.

    PubMed

    Hannachi, N; Guidara, K; Bulou, A; Gargouri, M; Hlel, F

    2010-10-01

    Chemical preparation, mid-infrared and Raman spectra of [N(C(3)H(7))(4)](2)Cd(2)Cl(6) are presented. Polarized Raman spectra of oriented single crystals have been recorded in the range 7-3900 cm(-1) under various polarization configurations with regard to the symmetry and the numbers of several band modes observed in the Raman and infrared spectra. The obtained results are consistent with the theoretical predictions based on the infrared and Raman selection rules.

  13. Detection of multiple H3 receptor affinity states utilizing [3H]A-349821, a novel, selective, non-imidazole histamine H3 receptor inverse agonist radioligand.

    PubMed

    Witte, David G; Yao, Betty Bei; Miller, Thomas R; Carr, Tracy L; Cassar, Steven; Sharma, Rahul; Faghih, Ramin; Surber, Bruce W; Esbenshade, Timothy A; Hancock, Arthur A; Krueger, Kathleen M

    2006-07-01

    1. A-349821 is a selective histamine H3 receptor antagonist/inverse agonist. Herein, binding of the novel non-imidazole H3 receptor radioligand [3H]A-349821 to membranes expressing native or recombinant H3 receptors from rat or human sources was characterized and compared with the binding of the agonist [3H]N--methylhistamine ([3H]NMH). 2. [3H]A-349821 bound with high affinity and specificity to an apparent single class of saturable sites and recognized human H3 receptors with 10-fold higher affinity compared to rat H3 receptors. [3H]A-349821 detected larger populations of receptors compared to [3H]NMH. 3. Displacement of [3H]A-349821 binding by H3 receptor antagonists/inverse agonists was monophasic, suggesting recognition of a single binding site, while that of H3 receptor agonists was biphasic, suggesting recognition of both high- and low-affinity H3 receptor sites. 4. pKi values of high-affinity binding sites for H3 receptor competitors utilizing [3H]A-349821 were highly correlated with pKi values obtained with [3H]NalphaMH, consistent with labelling of H3 receptors by [3H]A-349821. 5. Unlike assays utilizing [3H]NMH, addition of GDP had no effect on saturation parameters measured with [3H]A-349821, while displacement of [3H]A-349821 binding by the H3 receptor agonist histamine was sensitive to GDP. 6. In conclusion, [3H]A-349821 labels interconvertible high- and low-affinity states of the H3 receptor, and displays improved selectivity over imidazole-containing H3 receptor antagonist radioligands. [3H]A-349821 competition studies showed significant differences in the proportions and potencies of high- and low-affinity sites across species, providing new information about the fundamental pharmacological nature of H3 receptors.

  14. Temperature-sensitive high affinity (/sup 3/H)serotonin binding: characterization and effects of antidepressant treatment

    SciTech Connect

    Helmeste, D.M.; Tang, S.W.

    1984-08-13

    Characterization of temperature-sensitive (/sup 3/H)serotonin (5-HT) binding sites (1 and 4 nM Kd sites) revealed complex inhibition by neuroleptics and serotonin antagonists. There was no simple correlation with affinities for S/sub 1/ and S/sub 2/ receptors. In vivo pretreatment (48 h before) with mianserin did not alter B/sub max/ or Kd for the 1 nM Kd (/sup 3/H)5-HT site, although (/sup 3/H)ketanserin (S/sub 2/) densities were decreased by 50%. This suggested that possible S/sub 2/ components of (/sup 3/H)5-HT binding must be negligible, even though ketanserin competed with high affinity (IC/sub 50/ = 3 nM) for a portion of the 1 nM Kd (/sup 3/H)5-HT site. Low concentrations of mianserin inhibited the 1 nM Kd (/sup 3/H)5-HT site in a non-competitive manner, as shown by a decrease in B/sub max/ with no change in Kd after in vitro incubation. The complex inhibition data may therefore represent indirect interactions through another site.

  15. Inhibition of platelet (/sup 3/H)- imipramine binding by human plasma protein fractions

    SciTech Connect

    Strijewski, A.; Chudzik, J.; Tang, S.W.

    1988-01-01

    Inhibition of high-affinity (/sup 3/H)-imipramine binding to platelet membranes by human plasma fractions and isolated plasma proteins was investigated. Several plasma proteins were found to contribute to the observed apparent inhibition and this contribution was assessed in terms of inhibitor units. Alpha/sub 1/ acid glycoprotein, high density and low density lipoprotein, IgG and ..cap alpha../sub 1/-antitrypsin were identified as effective non-specific inhibitors. Alpha-1-acid glycoprotein was confirmed to be the most potent plasma protein inhibitor. Cohn fractions were evaluated for the presence of the postulated endocoid of (/sup 3/H)-imipramine binding site.

  16. Symmetry operation measures.

    PubMed

    Pinsky, Mark; Casanova, David; Alemany, Pere; Alvarez, Santiago; Avnir, David; Dryzun, Chaim; Kizner, Ziv; Sterkin, Alexander

    2008-01-30

    We introduce a new mathematical tool for quantifying the symmetry contents of molecular structures: the Symmetry Operation Measures. In this approach, we measure the minimal distance between a given structure and the structure which is obtained after applying a selected symmetry operation on it. If the given operation is a true symmetry operation for the structure, this distance is zero; otherwise it gives an indication of how different the transformed structure is from the original one. Specifically, we provide analytical solutions for measures of all the improper rotations, S n p, including mirror symmetry and inversion, as well as for all pure rotations, C n p. These measures provide information complementary to the Continuous Symmetry Measures (CSM) that evaluate the distance between a given structure and the nearest structure which belongs to a selected symmetry point-group.

  17. /sup 3/H-imipramine uptake into rat striatal slices and imipramine-induced /sup 3/H-dopamine efflux

    SciTech Connect

    Saito, R.; Kawasaki, K.; Ono, N.; Kamiya, H.

    1983-04-01

    The effect of imipramine on spontaneous efflux of radiolabelled dopamine (DA) from slices of rat striatum was examined by a superfusion method. Imipramine at concentrations of 10 - 100 microM enhanced the efflux of DA accumulated in a high-affinity uptake system in a concentration-dependent manner. This efflux of /sup 3/H-DA was not affected by conditions (Ca/sup 2 +/-free medium, 100 microM bretylium and 30 microM tetrodotoxin) which inhibited the release of /sup 3/H-DA by electrical stimulation. Furthermore, this imipramine-induced /sup 3/H-DA efflux was temperature-dependent. The uptake of /sup 3/H-imipramine into striatal slices was determined. This uptake was concentration- and temperature-dependent and increased linearly. These results are discussed in relation to the hypothesis that /sup 3/H-DA efflux by imipramine is connected with uptake of imipramine.

  18. Binding of /sup 3/H-acetylcholine to cholinergic receptors in bovine cerebral arteries

    SciTech Connect

    Shimohama, S.; Tsukahara, T.; Taniguchi, T.; Fujiwara, M.

    1985-11-18

    Cholinergic receptor sites in bovine cerebral arteries were analyzed using radioligand binding techniques with the cholinergic agonist, /sup 3/H-acetylcholine (ACh), as the ligand. Specific binding of /sup 3/H-ACh to membrane preparations of bovine cerebral arteries was saturable, of two binding sites, with dissociation constant (K/sub D/) values of 0.32 and 23.7 nM, and maximum binding capacity (Bmax) values of 67 and 252 fmol/mg protein, respectively. Specific binding of /sup 3/H-ACh was displaced effectively by muscarinic cholinergic agents and less effectively by nicotinic cholinergic agents. IC/sub 50/ values of cholinergic drugs for /sup 3/H-ACh binding were as follows: atropine, 38.5 nM; ACh, 59.8 nM; oxotremorine, 293 nM; scopolamine 474 nM; carbamylcholine, 990 nM. IC/sub 50/ values of nicotinic cholinergic agents such as nicotine, cytisine and ..cap alpha..-bungarotoxin exceeded 50 ..mu..M. Choline acetyltransferase activity was 1.09 nmol/mg protein/hour in the cerebral arteries. These findings suggest that the cholinergic nerves innervate the bovine cerebral arteries and that there are at least two classes of ACh binding sites of different affinities on muscarinic reporters in these arteries. 18 references, 2 figures, 2 tables.

  19. Assimilation of 3H in photosynthesizing leaves exposed to HTO.

    PubMed

    Guenot, J; Belot, Y

    1984-12-01

    Potato and wine grape plants were exposed for a period of 4 h to tritiated water vapor, and simultaneously to 14CO2 which served as a tracer for photosynthetic assimilation. During and after exposure, foliar samples were collected in which the exchangeable and nonexchangeable fractions of organic 3H were determined, taking care that the exchangeable fraction should not be lost to atmosphere. It was demonstrated that about 20% of the organic H in vegetation could be exchanged with 3H of tissue water, and that nonexchangeable 3H was fixed by photosynthesis. The kinetic behavior of the 2 forms was very different.

  20. Characterization of central alpha-adrenoceptors using /sup 3/H-clonidine and its derivatives

    SciTech Connect

    Jarrott, B.; Louis, W.J.; Summers, R.J.

    1983-02-01

    alpha-Adrenoceptors in brain can be studied readily by radioligand binding techniques. This provides valuable information not only on the distribution of receptors in brain regions, but also on the regulation of receptors. The usefulness of this technique is dependent in part on a radioligand with high specificity for the receptor under study. Researchers' studies have shown that /sup 3/H-clonidine does not bind exclusively to alpha 2-adrenoceptor subtypes, but also interacts with alpha 1-adrenoceptors. In contrast, /sup 3/H-guanfacine labels a high affinity alpha 2 subtype with good selectivity, but /sup 3/H-lofexidine probably labels with both alpha 2 and alpha 1-adrenoceptor binding sites.

  1. Effect of membrane protein concentration on binding of /sup 3/H-imipramine in human platelets

    SciTech Connect

    Barkai, A.I.; Kowalik, S.; Baron, M.

    1985-02-01

    Binding of /sup 3/H-imipramine to platelet membranes has been implicated as a marker for depression. Comparing /sup 3/H-IMI binding between depressed patients and normal subjects we observed an increase in the dissociation constant Kd with increasing membrane protein. This phenomenon was studied more rigorously in five normal subjects. Platelet membranes were prepared and adjusted to four concentrations of protein ranging from 100 to 800 micrograms/ml. The /sup 3/H-IMI binding parameters of maximum binding sites number (Bmax) and Kd were obtained by Scatchard analysis at each membrane concentration. A positive linear relationship was found between K/sub d/ values and the concentration of membrane protein in the assay, but no change was observed in Bmax. The variability in Kd values reported in the literature may be accounted for in part by the different concentrations of membrane protein used in various studies.

  2. Symmetry-protected topological entanglement

    NASA Astrophysics Data System (ADS)

    Marvian, Iman

    2017-01-01

    We propose an order parameter for the symmetry-protected topological (SPT) phases which are protected by Abelian on-site symmetries. This order parameter, called the SPT entanglement, is defined as the entanglement between A and B , two distant regions of the system, given that the total charge (associated with the symmetry) in a third region C is measured and known, where C is a connected region surrounded by A , B , and the boundaries of the system. In the case of one-dimensional systems we prove that in the limit where A and B are large and far from each other compared to the correlation length, the SPT entanglement remains constant throughout a SPT phase, and furthermore, it is zero for the trivial phase while it is nonzero for all the nontrivial phases. Moreover, we show that the SPT entanglement is invariant under the low-depth quantum circuits which respect the symmetry, and hence it remains constant throughout a SPT phase in the higher dimensions as well. Also, we show that there is an intriguing connection between SPT entanglement and the Fourier transform of the string order parameters, which are the traditional tool for detecting SPT phases. This leads to an algorithm for extracting the relevant information about the SPT phase of the system from the string order parameters. Finally, we discuss implications of our results in the context of measurement-based quantum computation.

  3. Pyrophosphate-bridged Cu(II) chain magnet: {[Na3Cu(P2O7)(NO3)].3H2O}n.

    PubMed

    Sartoris, Rosana P; Santana, Ricardo C; Baggio, Ricardo F; Peña, Octavio; Perec, Mireille; Calvo, Rafael

    2010-06-21

    A Cu(II)...Cu(II) pyrophosphate-bridged compound of formula {[Na(3)Cu(P(2)O(7))(NO(3))].3H(2)O}(n) (1) has been characterized. X-ray diffraction measurements show that it crystallizes in the monoclinic space group P2(1)/m, with unit cell dimensions a = 7.2492(5) A, b = 8.2446(6) A, c = 9.9050(7) A, beta = 107.123(1) degrees, and Z = 2. The structure consists of chains of Cu(II) cations at inversion symmetry sites bound to four equatorial oxygen atoms provided by two pyrophosphate anions halved by a symmetry plane and two axial oxygen atoms of nitrate anions. The molar magnetic susceptibility chi(0) of a powdered sample was measured in the temperature range 2 K < T < 273 K, and an isothermal magnetization curve, M(B(0),T), was obtained at T = 30 K, with the magnetic field B(0) between 0 and 5 T. Fitting a spin-chain model to the susceptibility data, we evaluate an antiferromagnetic exchange coupling 2J = -24.3(1) cm(-1) (defined as H(ex) = -2JS(i)S(j)) between Cu(II) neighbors. For any orientation of B(0), single-crystal electron paramagnetic resonance (EPR) spectra obtained at 9.8 and 33.9 GHz at 300 K display a single signal having a g matrix with orthorhombic symmetry, arising from the merger produced by the exchange interaction of the resonances corresponding to the two rotated Cu(II) sites. The g matrices of the individual molecules calculated assuming axial symmetry yielded principal values g(parallel) = 2.367(1) and g(perpendicular) = 2.074(1) at both frequencies, indicating a d(x(2)-y(2)) ground-state orbital for the Cu(II) ions. The angular variation of the EPR line width suggests exchange narrowing in a system with one-dimensional spin dynamics, as expected from the structure and susceptibility data. The results, discussed in terms of the crystal and electronic structures and of the spin dynamics of the compound, are compared with those obtained in other materials.

  4. Dopamine transporter; solubilization and characterization of ( sup 3 H) GBR-12935 binding in canine caudate

    SciTech Connect

    Sallee, F.R.

    1988-01-01

    The dopamine (DA) transporter protein, as indexed by ({sup 3}H)GBR-12935 binding, was solubilized from canine striatal membranes with the detergent digitonin. This solubilized protein retained the same pharmacological characteristics as membrane attached uptake sites. The binding of ({sup 3}H)GBR-12935 to solubilized preparations was specific, saturable and reversible with an equilibrium dissociation constant of approximately 3 nM and a maximum ligand binding (B{sub max}) of 3.4 pmol/mg protein. ({sup 3}H)GBR-12935 also bound to solubilized sites in a sodium-independent manner with a K{sub D} of approximately 6 nM and a B{sub max} of 1.2 {plus minus} 0.2 pmol/mg protein. Dopamine uptake inhibitors and substrates of DA uptake inhibited ({sup 3}H)GBR-12935 binding in a stereoselective and concentration dependent manner. For these compounds rank order of potency for inhibition of ({sup 3}H)GBR-12935 binding correlated with their potency for inhibition of dopamine uptake. K{sub D} values for DA uptake inhibitors in solubilized preparations correlated with those obtained on ({sup 3}H)GBR-12935 binding in the native state. The dopamine transporter appears to be a transmembrane glycoprotein by virtue of its absorption and specific elution from wheat germ agglutinin (WGA)-lectin column. Solubilization of the putative dopamine transporter with full retention of binding activity now allows for the purification and biochemical characterization of this important membrane protein.

  5. Autoradiographic localization of /sup 3/H-digoxin binding by neural cells in the medulla

    SciTech Connect

    Traurig, H.H.; Bhagat, A.; Bass, N.H.

    1985-01-01

    The purpose of this investigation was to localize binding sites for the cardiac glycoside digoxin in the medulla of the rat in vivo. Adult male Sprague-Dawley rats were injected (IV) with /sup 3/H-digoxin and killed 30 minutes later. Autoradiographs of medullas showed evidence of /sup 3/H-digoxin binding to small- and medium-sized neural cells in the regions of the nucleus solitarius, dorsal motor nucleus of the vagus, area postrema, and in the zone between the area postrema and the underlying neuropil. However, the parasympathetic preganglionic neurons of the dorsal motor nucleus were not labeled. The /sup 3/H-digoxin-labeled cells in the medulla were located mainly in the commissural and medial portions of nucleus solitarius at the level of the area postrema. Animals injected with unlabeled digoxin followed by /sup 3/H-digoxin showed reduced binding of radioactivity. The small- and medium-sized neurons of the caudal portions of the nucleus solitarius are internuncial in position with respect to cardiovascular afferents of the glossopharyngeal and vagus nerves and sympathetic and parasympathetic cardiovascular efferent neurons of the medulla. The results of this study suggest that these /sup 3/H-digoxin-labeled cells, presumably neurons of nucleus solitarius, may possess high affinity binding sites for digoxin. Further, the area postrema, which lacks a blood-brain barrier, may provide a portal of entry for /sup 3/H-digoxin into regions of the medulla known to contain neurons that play a role in the regulation of cardiac rhythm.

  6. Characterization of ( sup 3 H)alprazolam binding to central benzodiazepine receptors

    SciTech Connect

    McCabe, R.T.; Mahan, D.R.; Smith, R.B.; Wamsley, J.K. )

    1990-10-01

    The binding of the triazolobenzodiazepine ({sup 3}H)alprazolam was studied to characterize the in vitro interactions with benzodiazepine receptors in membrane preparations of rat brain. Studies using nonequilibrium and equilibrium binding conditions for ({sup 3}H)alprazolam resulted in high specific to nonspecific (signal to noise) binding ratios. The binding of ({sup 3}H)alprazolam was saturable and specific with a low nanomolar affinity for benzodiazepine receptors in the rat brain. The Kd was 4.6 nM and the Bmax was 2.6 pmol/mg protein. GABA enhanced ({sup 3}H)alprazolam binding while several benzodiazepine receptor ligands were competitive inhibitors of this drug. Compounds that bind to other receptor sites had a very weak or negligible effect on ({sup 3}H)alprazolam binding. Alprazolam, an agent used as an anxiolytic and in the treatment of depression, acts in vitro as a selective and specific ligand for benzodiazepine receptors in the rat brain. The biochemical binding profile does not appear to account for the unique therapeutic properties which distinguish this compound from the other benzodiazepines in its class.

  7. /sup 3/H-imipramine binding in aged mouse brain: regulation by ions and serotonin

    SciTech Connect

    Severson, J.A.

    1986-03-01

    The density of binding sites (Bmax) for /sup 3/H-imipramine was elevated in cerebral cortical, hypothalamic and hippocampal membranes from 24 month old male C57BL/6J mice. Cerebellar binding was constant with increasing age. There were no changes in the equilibrium dissociation constant (Kd) for /sup 3/H-imipramine in any brain region. The increase in the binding of /sup 3/H-imipramine induced by sodium and chloride ions in vitro was diminished in cerebral cortical homogenates from aged mice; both the sodium-sensitive and chloride-sensitive components of binding were about 50% less in aged mice. Dose-response curves indicated that the effectiveness with which chloride enhanced binding was similar with age, even though the absolute increase in binding was less. The rate of dissociation of /sup 3/H-imipramine from cerebral cortical homogenates was similar with age and serotonin slowed the rate of dissociation equally at all ages. Possible mechanisms for the age-related increase in brain /sup 3/H-imipramine binding are discussed. Ion-sensitive binding is discussed in relationship to the current controversy surrounding desipramine-sensitive versus ion-sensitive binding.

  8. Interactions of full and partial agonists with HT29 cell alpha 2-adrenoceptor: comparative study of (/sup 3/H)UK-14,304 and (/sup 3/H)clonidine binding

    SciTech Connect

    Paris, H.; Galitzky, J.; Senard, J.M.

    1989-03-01

    The HT29 cell line expresses alpha 2-adrenoceptors that are negatively coupled to the adenylate cyclase system and is, in this respect, a valuable model for in vitro study of alpha 2-adrenergic receptivity in a tissue from human origin. In these cancerous cells, UK-14,304 is a full agonist of the alpha 2-adrenergic-mediated inhibition of the vasoactive intestinal peptide-induced cyclic AMP accumulation, whereas clonidine acts only as a partial agonist. In the present report, we used (3H)UK-14,304 as radioligand and compared its binding characteristics with those of (3H)clonidine in order to better understand the difference between full and partial agonism on the basis of agonist/receptor interactions. (3H)UK-14,304 labeled with high affinity (KD = 0.39 +/- 0.05 nM) a single class of sites having the pharmacological specificity of an alpha 2-adrenoceptor. Comparison of (3H)UK-14,304, (3H)clonidine, and (3H)yohimbine Bmax proved that both 3H-agonists labeled the same number of sites (172 +/- 14 versus 179 +/- 21 fmol/mg of protein), whereas the 3H-antagonist recognized more sites (246 +/- 22 fmol/mg of protein). Inhibition of (3H)yohimbine by the two agonists was consistent with the existence of an heterogeneous population of receptors and analysis of the data according a two-site inhibition model showed (1) that the KiL/KiH ratio was higher for UK-14,304 than for clonidine and (2) that the percentages of high affinity state receptor recognized by both agonists were identical (56 +/- 4% with UK-14,304 and 59 +/- 5% with clonidine). Kinetics of (3H)UK-14,304 and (3H)clonidine binding indicated more complex agonist-receptor interactions than equilibrium data did. Association as well as dissociation of both radioligands appeared to be biphasic, suggesting a relative heterogeneity of 3H-agonist binding sites.

  9. B-site ordered double perovskite LaBa1-xSrxZnSbO6 (0 ≤ x ≤ 1): Sr(2+)-doping-induced symmetry evolution and structure-luminescence correlations.

    PubMed

    Jiang, Pengfei; Zhou, Zhengyang; Gao, Wenliang; Cong, Rihong; Yang, Tao

    2016-03-07

    The study of perovskites has been active for a long time. Here, we rationally designed and prepared a double perovskite, LaBaZnSbO6, by selecting Zn(2+) and Sb(5+) with large size and charge differences, and, indeed, complete B-site ordering can be achieved. Careful study using powder X-ray diffraction data pinpointed its space group to be I2/m, which has rarely been seen in double perovskites. Thereafter, an interesting observation of Sr(2+)-doping-induced symmetry evolution from I2/m to P21/n was confirmed in the complete solid solutions LaBa1-xSrxZnSbO6, where the tilting system also transferred from a(-)a(-)c(0) to a(-)a(-)c(+). The transition boundary is around x = 0.4. It can also be visualized by the variation of θ (defined as c/[(a + b)/2]), which is associated with the anisotropic shrinkage of the unit cell lattice and indeed shows a minimum at x = 0.4. Such a successive modulation of both the structural symmetry and the average La/Ba/Sr-O bond distances (revealed by Rietveld refinements) motivated us to study the Eu(3+) luminescence in La0.95Eu0.05Ba1-xSrxZnSbO6. Interestingly, the maximum of charge transfer absorption of Eu(3+) shows a precise changing tendency with the A-O bond distances along with the Sr(2+) doping, clearly revealing the structure-luminescence correlations.

  10. Pentamidine analogs as inhibitors of [3H]MK-801 and [3H]ifenprodil binding to rat brain NMDA receptors

    PubMed Central

    Berger, Michael L.; Maciejewska, Dorota; Vanden Eynde, Jean Jacques; Mottamal, Madhusoodanan; Żabiński, Jerzy; Kaźmierczak, Paweł; Rezler, Mateusz; Jarak, Ivana; Piantanida, Ivo; Karminski-Zamola, Grace; Mayence, Annie; Rebernik, Patrick; Kumar, Arvind; Ismail, Mohamed A.; Boykin, David W.; Huang, Tien L.

    2016-01-01

    The anti-protozoal drug pentamidine is active against opportunistic Pneumocystis pneumonia, but in addition has several other biological targets, including the NMDA receptor (NR). Here we describe the inhibitory potencies of 76 pentamidine analogs at 2 binding sites of the NR, the channel binding site labeled with [3H]MK-801 and the [3H]ifenprodil binding site. Most analogs acted weaker at the ifenprodil than at the channel site. The spermine-sensitivity of NR inhibition by the majority of the compounds was reminiscent of other long-chain dicationic NR blockers. The potency of the parent compound as NR blocker was increased by modifying the heteroatoms in the bridge connecting the 2 benzamidine moieties and also by integrating the bridge into a seven-membered ring. Docking of the 45 most spermine-sensitive bisbenzamidines to a recently described acidic interface between the N-terminal domains of GluN1 and GluN2B mediating polyamine stimulation of the NR revealed the domain contributed by GluN1 as the most relevant target. PMID:26117647

  11. From physical symmetries to emergent gauge symmetries

    NASA Astrophysics Data System (ADS)

    Barceló, Carlos; Carballo-Rubio, Raúl; Di Filippo, Francesco; Garay, Luis J.

    2016-10-01

    Gauge symmetries indicate redundancies in the description of the relevant degrees of freedom of a given field theory and restrict the nature of observable quantities. One of the problems faced by emergent theories of relativistic fields is to understand how gauge symmetries can show up in systems that contain no trace of these symmetries at a more fundamental level. In this paper we start a systematic study aimed to establish a satisfactory mathematical and physical picture of this issue, dealing first with abelian field theories. We discuss how the trivialization, due to the decoupling and lack of excitation of some degrees of freedom, of the Noether currents associated with physical symmetries leads to emergent gauge symmetries in specific situations. An example of a relativistic field theory of a vector field is worked out in detail in order to make explicit how this mechanism works and to clarify the physics behind it. The interplay of these ideas with well-known results of importance to the emergent gravity program, such as the Weinberg-Witten theorem, are discussed.

  12. A new family of Ln₇ clusters with an ideal D(3h) metal-centered trigonal prismatic geometry, and SMM and photoluminescence behaviors.

    PubMed

    Mazarakioti, Eleni C; Poole, Katye M; Cunha-Silva, Luis; Christou, George; Stamatatos, Theocharis C

    2014-08-14

    The first use of the flexible Schiff base ligand N-salicylidene-2-aminocyclohexanol in metal cluster chemistry has afforded a new family of Ln7 clusters with ideal D(3h) point group symmetry and metal-centered trigonal prismatic topology; solid-state and solution studies revealed SMM and photoluminescence behaviors.

  13. Characterisation of the specific binding of the histamine H3 receptor antagonist radioligand [3H]GR168320.

    PubMed

    Brown, J D; O'Shaughnessy, C T; Kilpatrick, G J; Scopes, D I; Beswick, P; Clitherow, J W; Barnes, J C

    1996-09-12

    We have examined the specific binding of the tritiated derivative of the potent histamine H3 receptor antagonist, [3,4-3H2]-cyclohex-yl-¿[4-(3H-imidazol-4-yl)-piperidin-l-yl] iminomethyl¿- amine ([3H]GR168320), to homogenates of rat cerebral cortex. Specific binding of [3H]GR168320 at 37 degrees C associated and dissociated rapidly. Binding was saturable (Bmax 412 +/- 89 fmol/mg protein) and of high affinity (Kd 0.12 +/- 0.11 nM). Saturation studies suggested the involvement of a single site. Histamine H3 receptor agonists and antagonists inhibited [3H]GR168320 binding with high affinity. Agonist and antagonist affinities correlated when compared with affinities obtained using the tritiated histamine H3 agonist radioligand N alpha-methylhistamine.

  14. Psychotomimetic opiate receptors labeled and visualized with (+)-(/sup 3/H)3-(3-hydroxyphenyl)-N-(1-propyl)piperidine

    SciTech Connect

    Largent, B.L.; Gundlach, A.L.; Snyder, S.H.

    1984-08-01

    3-(3-Hydroxyphenyl)-N-(1-propyl)piperidine (3-PPP) has been proposed as a selective dopamine autoreceptor agonist in the central nervous system. This report describes the pharmacology and localization of specific high-affinity binding sites for (+)-(/sup 3/H)3-PPP in brain. The drug specificity of (+)-(/sup 3/H)3-PPP binding is identical to that of sigma receptors, which may mediate psychotomimetic effects of some opiates. Haloperidol and the opioid derivatives, pentazocine, cyclazocine, and SKF 10,047 are potent inhibitors of (+)-(/sup 3/H)3-PPP binding. Stereoselectivity is exhibited for the (+) isomers of cyclazocine and SKF 10.047 at the sigma site, opposite to the stereoselectivity seen at ..mu.., sigma, and k opiate receptors. (+)-(/sup 3/H)3-PPP does not label dopamine receptors, as potent dopamine agonists and antagonists are weak inhibitors of binding and the localization of specific (+)-(/sup 3/H)3-PPP binding sites does not parallel that of dopamine neurons. Discrete localizations of (+)-(/sup 3/H)3-PPP binding sites in many brain areas including limbic, midbrain, brainstem, and cerebellar regions may explain psychotomimetic actions of opiates and behavior effects of 3-PPP. 41 references, 2 figures, 1 table.

  15. Stimulation of [3H] GABA and beta-[3H] alanine release from rat brain slices by cis-4-aminocrotonic acid.

    PubMed

    Chebib, M; Johnston, G A

    1997-02-01

    cis-4-Aminocrotonic acid (CACA; 100 microM), an analogue of GABA in a folded conformation, stimulated the passive release of [3H] GABA from slices of rat cerebellum, cerebral cortex, retina, and spinal cord and of beta-[3H]alanine from slices of cerebellum and spinal cord without influencing potassium-evoked release. In contrast, CACA (100 microM) did not stimulate the passive release of [3H]taurine from slices of cerebellum and spinal cord or of D-[3H]aspartate from slices of cerebellum and did not influence potassium-evoked release of [3H]-taurine from the cerebellum and spinal cord and D-[3H]-aspartate from the cerebellum. These results suggest that the effects of CACA on GABA and beta-alanine release are due to CACA acting as a substrate for a beta-alanine-sensitive GABA transport system, consistent with CACA inhibiting the uptake of beta-[3H]alanine into slices of rat cerebellum and cerebral cortex. The observed Ki for CACA against beta-[3H]alanine uptake in the cerebellum was 750 +/- 60 microM. CACA appears to be 10-fold weaker as a substrate for the transporter system than as an agonist for the GABAc receptor. The effects of CACA on GABA and beta-alanine release provide indirect evidence for a GABA transporter in cerebellum, cerebral cortex, retina, and spinal cord that transports GABA, beta-alanine, CACA, and nipecotic acid that has a similar pharmacological profile to that of the GABA transporter, GAT-3, cloned from rat CNS. The structural similarities of GABA, beta-alanine, CACA, and nipecotic acid are demonstrated by computer-aided molecular modeling, providing information on the possible conformations of these substances being transported by a common carrier protein.

  16. Uptake of /sup 3/H-choline and synthesis of /sup 3/H-acetylcholine by human penile corpus cavernosum

    SciTech Connect

    Blanco, R.; Saenz de Tejada, I.; Azadzoi, K.; Goldstein, I.; Krane, R.J.; Wotiz, H.H.; Cohen, R.A.

    1986-03-05

    The neuroeffectors which relax penile smooth muscle and lead to erection are unknown; physiological studies of human corpus cavernosum, in vitro, have suggested a significant role of cholinergic neurotransmission. To further characterize the importance of cholinergic nerves, biopsies of human corpus cavernosum were obtained at the time of penile prosthesis implantation. Tissues were incubated in /sup 3/H-choline (10/sup -5/M, 80 Ci/mmol) in oxygenated physiological salt solution at 37/sup 0/C, pH 7.4 for 1 hour. Radiolabelled compounds were extracted with perchloric acid (0.4 M) and acetylcholine and choline were separated by HPLC; /sup 14/C-acetylcholine was used as internal standard. /sup 3/H-choline was accumulated by the tissues (20 +/- 1.9 fmol/mg), and /sup 3/H-acetylcholine was synthesized (4.0 +/- 1.1 fmol/mg). In control experiments, heating of the tissue blocked synthesis of /sup 3/H-acetylcholine. Inhibition of high affinity choline transport by hemicholinium-3 (10/sup -5/M) diminished tissue accumulation of /sup 3/H-choline and significantly reduced the synthesis of /sup 3/H-acetylcholine (0.5 +/ 0.2 fmol/mg, p < 0.05). These results provide direct evidence of neuronal accumulation of choline and enzymatic conversion to acetylcholine in human corpus cavernosum. Taken together with the physiological studies, it can be concluded that cholinergic neurotransmission in human corpus cavernosum plays a role in penile erection.

  17. Dynamic Paper Constructions for Easier Visualization of Molecular Symmetry

    ERIC Educational Resources Information Center

    Sein, Lawrence T., Jr.

    2010-01-01

    A system for construction of simple poster-board models is described. The models dynamically demonstrate the symmetry operations of proper rotation, improper rotation, reflection, and inversion for the chemically important point groups D[subscript 3h], D[subscript 4h], D[subscript 5h], D[subscript 6h], T[subscript d], and O[subscript h]. The…

  18. Rabbit blastocysts accumulate [3H]prostaglandins in vitro.

    PubMed

    Jones, M A; Harper, M J

    1984-08-01

    Rabbit blastocysts obtained on days 5, 6, and 6.8 of pregnancy were incubated in vitro in Tyrode's buffer with 3H-labeled prostaglandins (PGs). Accumulation of PGs was studied, using Whatman GF/F filters to separate bound and free ligands. The uptake and efflux of [3H]PGs were studied as a function of PG type, incubation time, temperature, and effect of metabolic inhibitors as well as age and number of blastocysts. Blastocysts of the same age accumulated approximately the same amount of [3H]PGE2 and [3H]PGF2 alpha from their environment; however, there was no apparent saturation over a PG concentration range of 1-1000 nM. Both the uptake and efflux of PG were age dependent, with older blastocysts accumulating more PGs. Approximately 90% of the [3H]PGs appear to be transported into the blastocoelic fluid, with little PG remaining in the blastomeres. PG accumulation was relatively insensitive to azide, ouabain, cyanide, or bromcresol green, but was affected by incubation at 0 C or the addition of indomethacin (10 micrograms/ml). No catabolism of the accumulated PGs was observed. The release of PGE2 in general did not differ from that of PGF2 alpha, except on day 6.8 of pregnancy when PGE2 was released more rapidly than on day 6. We conclude that rabbit blastocysts can accumulate PGs from their environment, which may imply a storage potential in the blastocyst and release before implantation.

  19. Enhanced binding of /sup 3/H-arginine8-vasopressin in the Brattleboro rat

    SciTech Connect

    Shewey, L.M.; Dorsa, D.M.

    1986-07-01

    Specific binding sites for 3(H)-arginine8-vasopressin (AVP) were characterized using membrane preparations of liver, renal medulla and brain (septal) tissue of heterozygous (HE) and homozygous (HO) Brattleboro (BB) rats. Measurement of binding sites indicated that significantly greater numbers of AVP receptors are present in the liver and septum of HO-BB rats. Similar numbers of AVP receptors were present in renal medullary tissue from HO-BB and HE-BB rats. Higher equilibrium dissociation constants were measured in the HO-BB septal tissue indicating a lower affinity of the brain receptor for 3(H)-AVP than in heterozygotes. No significant differences in AVP receptor affinity were noted in liver or kidney tissue. It is concluded that up-regulation of AVP receptor number and, in the brain, alterations in AVP receptor affinity may occur in the absence of endogenous AVP.

  20. Neurotensin decreases high affinity [3H]-ouabain binding to cerebral cortex membranes.

    PubMed

    Rosin, Carina; Ordieres, María Graciela López; Arnaiz, Georgina Rodríguez de Lores

    2011-12-10

    Previous work from this laboratory showed the ability of neurotensin to inhibit synaptosomal membrane Na(+), K(+)-ATPase activity, the effect being blocked by SR 48692, a non-peptidic antagonist for high affinity neurotensin receptor (NTS1) [López Ordieres and Rodríguez de Lores Arnaiz 2000; 2001]. To further study neurotensin interaction with Na(+), K(+)-ATPase, peptide effect on high affinity [(3)H]-ouabain binding was studied in cerebral cortex membranes. It was observed that neurotensin modified binding in a dose-dependent manner, leading to 80% decrease with 1 × 10(-4)M concentration. On the other hand, the single addition of 1 × 10(-6)M, 1 × 10(-5)M and 1 × 10(-4)M SR 48692 (Sanofi-Aventis, U.S., Inc.) decreased [(3)H]-ouabain binding (in %) to 87 ± 16; 74 ± 16 and 34 ± 17, respectively. Simultaneous addition of neurotensin and SR 48692 led to additive or synergic effects. Partial NTS2 agonist levocabastine inhibited [(3)H]-ouabain binding likewise. Saturation assays followed by Scatchard analyses showed that neurotensin increased K(d) value whereas failed to modify B(max) value, indicating a competitive type interaction of the peptide at Na(+), K(+)-ATPase ouabain site. At variance, SR 48692 decreased B(max) value whereas it did not modify K(d) value. [(3)H]-ouabain binding was also studied in cerebral cortex membranes obtained from rats injected i. p. 30 min earlier with 100 μg and 250 μg/kg SR 48692. It was observed that the 250 μg/kg SR 48692 dose led to 19% decrease in basal [(3)H]-ouabain binding. After SR 48692 treatments, addition of 1 × 10(-6)M led to additive or synergic effect. Results suggested that [(3)H]-ouabain binding inhibition by neurotensin hardly involves NTS1 receptor.

  1. Symmetries in Lagrangian Dynamics

    ERIC Educational Resources Information Center

    Ferrario, Carlo; Passerini, Arianna

    2007-01-01

    In the framework of Noether's theorem, a distinction between Lagrangian and dynamical symmetries is made, in order to clarify some aspects neglected by textbooks. An intuitive setting of the concept of invariance of differential equations is presented. The analysis is completed by deriving the symmetry properties in the motion of a charged…

  2. Symmetry and Interculturality

    ERIC Educational Resources Information Center

    Marchis, Iuliana

    2009-01-01

    Symmetry is one of the fundamental concepts in Geometry. It is a Mathematical concept, which can be very well connected with Art and Ethnography. The aim of the article is to show how to link the geometrical concept symmetry with interculturality. For this mosaics from different countries are used.

  3. 1-aryl-6,7-methylenedioxy-3H-quinazolin-4-ones as anticonvulsant agents.

    PubMed

    Zappalà, Maria; Grasso, Silvana; Micale, Nicola; Zuccalà, Giuseppe; Menniti, Frank S; Ferreri, Guido; De Sarro, Giovambattista; De Micheli, Carlo

    2003-12-15

    A set of novel 1-aryl-6,7-methylenedioxy-3H-quinazolin-4-(thi)ones (3a-f) has been designed and screened as anticonvulsant agents in DBA/2 mice. The new compounds are provided with anticonvulsant properties comparable to those of GYKI 52466. To clarify the mode of action, their affinity for the quinazolinone/2,3-benzodiazepine site of the AMPA receptor complex has been assayed.

  4. Modulation of [3H]MK-801 binding to NMDA receptors in vivo and in vitro.

    PubMed

    Murray, F; Kennedy, J; Hutson, P H; Elliot, J; Huscroft, I; Mohnen, K; Russell, M G; Grimwood, S

    2000-06-02

    [3H]MK-801 binding in vivo was used to determine the occupancy of NMDA receptor ligands shown to allosterically modulate binding in vitro. ED(50) values (mg/kg) were obtained for the channel blockers (+)-5-methyl-10,11-dihydro-5,4-dibenzo[a,d]cyclohepten-5,10-imine maleate ((+)-MK-801, 0.2), 1-(1-phenylcyclohexyl)piperidine (phencyclidine, PCP, 1.7) and ketamine (4.4). Antagonists at the glutamate (DL-(2-carboxypiperazine-4-yl)propyl-1-phosphonate (DL-CPP, 5.7)) and glycine site (7-Chloro-4-hydroxy-3-(3-phenoxy)-phenyl-2(H)quinolinone (L-701,324, 14.1), 3R(+)cis-4-methyl-pyrrollid-2-one (L-687,414, 15.1)) inhibited [3H]MK-801 binding in vivo to varying maximum levels (69%, 103% and 45%, respectively). NR2B subunit-selective compounds acting at the ifenprodil site inhibited [3H]MK-801 in vivo by a maximum of 52-72% and gave ED(50) values (mg/kg) of: (+/-)-(1S*, 2S*)-1-(4-hydroxyphenyl)-2-(4-hydroxy-4-phenylpiperidino)-1-propanol ((+/-)CP-101,606), 1.9; (+/-)-(3R, 4S)-3-[4-(4-fluorophenyl)-4-hydroxypiperidin-1-yl]chroman-4,7-diol ((+/-)CP-283,097), 1.8; (+/-)-(R*, S*)-alpha-(4-hydroxyphenyl)-beta-methyl-4-(phenylmethyl)-1-piperidine propanol ((+/-)Ro 25-6981), 1.0; ifenprodil, 6.0. The glycine site agonist D-serine stimulated binding to 151% of control with an ED(50) of 1.7 mg/kg. Results show that [3H]MK-801 binding in vivo may be used to measure receptor occupancy of ligands acting not only within the ion channel but also at modulatory sites on the NMDA receptor complex.

  5. Purification of neuropathy target esterase from avian brain after prelabelling with [3H]diisopropyl phosphorofluoridate.

    PubMed

    Rüffer-Turner, M E; Read, D J; Johnson, M K

    1992-01-01

    Neuropathy target esterase from hen brains was radiolabelled at the active site with [3H]diisopropyl phosphorofluoridate. The labelled protein was purified by differential centrifugation and Nonidet P40 solubilization, detergent phase partitioning, anion exchange, and preparative sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE). The volatilizable counts assay and analytical SDS-PAGE were used to monitor the protein. The 150-kDa subunit polypeptide appears as a single band on analytical SDS-PAGE.

  6. High affinity binding of (/sup 3/H)neurotensin of rat uterus

    SciTech Connect

    Pettibone, D.J.; Totaro, J.A.

    1987-11-01

    (/sup 3/H)Neurotensin (NT) was found to bind specifically and with high affinity to crude membranes prepared from rat uterus. Scatchard analysis of saturation binding studies indicated that (/sup 3/H)NT apparently binds to two sites (high affinity Kd 0.5 nM; low affinity Kd 9 nM) with the density of high affinity sites (41 fmoles/mg prot.) being about one-third that of the low affinity sites (100 fmoles/mg prot.). In competition studies, NT and various fragments inhibited (/sup 3/H)NT binding with the following potencies (approximately IC50): NT 8-13 (0.4 nM), NT 1-13 (4 nM), NT 9-13 (130 nM), NT 1-11, NT 1-8 (greater than 100 microM). Quantitatively similar results were obtained using brain tissue. These findings raise the possibility of a role for NT in uterine function.

  7. Effects of linalool on [(3)H]MK801 and [(3)H] muscimol binding in mouse cortical membranes.

    PubMed

    Brum, L F; Elisabetsky, E; Souza, D

    2001-08-01

    Linalool is a monoterpene compound reported to be a major component of essential oils of several aromatic species. Several linalool-producing species are used in traditional medical systems for sedative purposes, including the interruption and prevention of seizures. Previous studies in mice revealed that linalool modulates glutamatergic (competitive antagonism of L-[(3)H]glutamate binding, delayed intraperitoneal NMDA-induced convulsions and blockade of intracerebroventricular Quin-induced convulsions) and GABAergic transmission (protection against pentylenetetrazol and picrotoxin-induced convulsions). To further clarify the anticonvulsive mechanisms of linalool, we studied the effects of linalool on binding of [(3)H]MK801 (NMDA antagonist) and [(3)H]muscimol (GABA(A) agonist) to mouse cortical membranes. Linalool showed a dose dependent non-competitive inhibition of [(3)H]MK801 binding (IC(50) = 2.97 mM) but no effect on [(3)H]muscimol binding. The data suggest that the anticonvulsant mode of action of linalool includes a direct interaction with the NMDA receptor complex. The data do not, however, support a direct interaction of linalool with GABA(A) receptors, although changes in GABA-mediated neuronal inhibition or effects on GABA release and uptake cannot be ruled out.

  8. Internal symmetry in protein structures: prevalence, functional relevance and evolution.

    PubMed

    Balaji, Santhanam

    2015-06-01

    Symmetry has been found at various levels of biological organization in the protein structural universe. Numerous evolutionary studies have proposed connections between internal symmetry within protein tertiary structures, quaternary associations and protein functions. Recent computational methods, such as SymD and CE-Symm, facilitate a large-scale detection of internal symmetry in protein structures. Based on the results from these methods, about 20% of SCOP folds, superfamilies and families are estimated to have structures with internal symmetry (Figure 1d). All-β and membrane proteins fold classes contain a relatively high number of unique instances of internal symmetry. In addition to the axis of symmetry, anecdotal evidence suggests that, the region of connection or contact between symmetric units could coincide with functionally relevant sites within a fold. General principles that underlie protein internal symmetry and their connections to protein structural integrity and functions remain to be elucidated.

  9. R-matrix description of particle energy spectra produced by low-energy 3H + 3H reactions

    DOE PAGES

    Brune, C. R.; Caggiano, J. A.; Sayre, D. B.; ...

    2015-07-20

    An R-matrix model for three-body final states is presented and applied to a recent measurement of the neutron energy spectrum from the 3H + 3H→ 2n + α reaction. The calculation includes the n alpha and n n interactions in the final state, angular momentum conservation, antisymmetrization, and the interference between different channels. A good fit to the measured spectrum is obtained, where clear evidence for the 5He ground state is observed. The model is also used to predict the alpha-particle spectrum from 3H + 3H as well as particle spectra from 3He + 3He. The R-matrix approach presented heremore » is very general, and can be adapted to a wide variety of problems with three-body final states.« less

  10. [Pharmacokinetics and biodistribution of 3H-norcantharidin in mice].

    PubMed

    Wei, Chun-Min; Wang, Ben-Jie; Ma, Ya; Sun, Zi-Ping; Li, Xiao-Li; Guo, Rui-Chen

    2007-05-01

    A single dose of 3H-norcantharidin solution was intragastrically given, blood, tissues, urine and feces were collected as scheduled, and radioactivity in these samples was determined by tritium tracing method to investigate the pharmacokinetics, tissue distribution and excretion of norcantharidin in Kunming mice. The pharmacokinetic characteristics of norcantharidin were evaluated by DAS version 2.0. The blood concentration reached to maximum 0. 5 h after intragastric administration. The radioactivity in tissues was high in small intestine, gallbladder, stomach, adrenal gland, kidney, heart and uterus 15 minutes after administration, descending with time, and high in gallbladder, adrenal gland and uterus 3 hours post dosing. The 24 h accumulative excretion ratio of urine and feces were 65.40% and 1.33% respectively. 3H-norcantharidin was easily absorbed after orally given to mice, the radioactivity was high and existed for a long-time in gallbladder, adrenal gland and uterus, and low but also existed for a long-time in large intestine, thymus and fat tissue. 3H-norcantharidin was declined quickly in small intestine, stomach, kidney and heart, and occurred rarely in brain. Norcantharidin was excreted mainly by urinary route and seldom in feces, which may be the cause of the urinary stimulation side effects observed. Because the radioactivity measured were the sum of 3H labeled norcantharidin and its metabolites, further studies on the disposition of norcantharidin in mammal animals, on the separation or identification of metabolites and, if any, on their activities, are fairly needed.

  11. Rabbit blastocysts accumulate (/sup 3/H)prostaglandins in vitro

    SciTech Connect

    Jones, M.A.; Harper, M.J.

    1984-08-01

    Rabbit blastocysts obtained on days 5, 6, and 6.8 of pregnancy were incubated in vitro in Tyrode's buffer with /sup 3/H-labeled prostaglandins (PGs). Accumulation of PGs was studied, using Whatman GF/F filters to separate bound and free ligands. The uptake and efflux of (/sup 3/H)PGs were studied as a function of PG type, incubation time, temperature, and effect of metabolic inhibitors as well as age and number of blastocysts. Blastocysts of the same age accumulated approximately the same amount of (/sup 3/H)PGE2 and (/sup 3/H)PGF2 alpha from their environment; however, there was no apparent saturation over a PG concentration range of 1-1000 nM. Both the uptake and efflux of PG were age dependent, with older blastocysts accumulating more PGs. Approximately 90% of the (/sup 3/H)PGs appear to be transported into the blastocoelic fluid, with little PG remaining in the blastomeres. PG accumulation was relatively insensitive to azide, ouabain, cyanide, or bromcresol green, but was affected by incubation at 0 C or the addition of indomethacin (10 micrograms/ml). No catabolism of the accumulated PGs was observed. The release of PGE2 in general did not differ from that of PGF2 alpha, except on day 6.8 of pregnancy when PGE2 was released more rapidly than on day 6. The authors conclude that rabbit blastocysts can accumulate PGs from their environment, which may imply a storage potential in the blastocyst and release before implantation.

  12. A universal symmetry detection algorithm.

    PubMed

    Maurer, Peter M

    2015-01-01

    Research on symmetry detection focuses on identifying and detecting new types of symmetry. The paper presents an algorithm that is capable of detecting any type of permutation-based symmetry, including many types for which there are no existing algorithms. General symmetry detection is library-based, but symmetries that can be parameterized, (i.e. total, partial, rotational, and dihedral symmetry), can be detected without using libraries. In many cases it is faster than existing techniques. Furthermore, it is simpler than most existing techniques, and can easily be incorporated into existing software. The algorithm can also be used with virtually any type of matrix-based symmetry, including conjugate symmetry.

  13. Competition for in vitro ( sup 3 H)gibberellin A sub 4 binding in cucumber by substituted phthalimides

    SciTech Connect

    Yalpani, N.; Suttle, J.C.; Hultstrand, J.F. ); Rodaway, S.J. )

    1989-11-01

    Certain N-substituted phthalimides (NSPs) have gibberellin (GA)-like activity in a number of GA bioassays. The interaction between representative NSPs and a protein fraction from cucumber (Cucumis sativus L.) hypocotyls that has GA-binding characteristics consistent with those expected of GA receptors was studied. Analysis of in vitro equilibrium saturation data indicated the presence of only one class of high affinity ({sup 3}H)GA{sub 4} binding sites (K{sub d} {approximately}30 nanomolar, n = 0.25 picomole per milligram of protein). In the presence of 6 or 60 micromolar 1-(3-chlorophthalimido)-cyclohexanecarboximide (AC-94,377), the K{sub d} for ({sup 3}H)GA{sub 4} increased, whereas the maximum number of saturable ({sup 3}H)GA{sub 4} binding sites did not change significantly. The dissociation of ({sup 3}H)GA{sub 4} from its binding sites was complex and was best described by a bi-exponential equation. AC-94,377 did not affect the rates of ({sup 3}H)GA{sub 4} dissociation from its binding sites. These results implied that AC-94,377 and ({sup 3}H)GA{sub 4} compete for binding to the same sites. A correlation was observed between the activity of over 20 NSPs in the cucumber hypocotyl bioassay and their in vitro affinity for the GA binding sites. Our observations lend further support to the notion that certain GA binding proteins in cucumber cytosol are GA receptors and also provide a molecular explanation for the GA-like in vivo activity of some NSPs.

  14. Dynamical symmetries for fermions

    SciTech Connect

    Guidry, M.

    1989-01-01

    An introduction is given to the Fermion Dynamical Symmetry Model (FDSM). The analytical symmetry limits of the model are then applied to the calculation of physical quantities such as ground-state masses and B(E{sub 2}) values in heavy nuclei. These comparisons with data provide strong support for a new principle of collective motion, the Dynamical Pauli Effect, and suggest that dynamical symmetries which properly account for the pauli principle are much more persistent in nuclear structure than the corresponding boson symmetries. Finally, we present an assessment of criticisms which have been voiced concerning the FDSM, and a discussion of new phenomena and exotic spectroscopy'' which may be suggested by the model. 14 refs., 8 figs., 4 tabs.

  15. Dynamical spacetime symmetry

    NASA Astrophysics Data System (ADS)

    Lovelady, Benjamin C.; Wheeler, James T.

    2016-04-01

    According to the Coleman-Mandula theorem, any gauge theory of gravity combined with an internal symmetry based on a Lie group must take the form of a direct product in order to be consistent with basic assumptions of quantum field theory. However, we show that an alternative gauging of a simple group can lead dynamically to a spacetime with compact internal symmetry. The biconformal gauging of the conformal symmetry of n-dimensional Euclidean space doubles the dimension to give a symplectic manifold. Examining one of the Lagrangian submanifolds in the flat case, we find that in addition to the expected S O (n ) connection and curvature, the solder form necessarily becomes Lorentzian. General coordinate invariance gives rise to an S O (n -1 ,1 ) connection on the spacetime. The principal fiber bundle character of the original S O (n ) guarantees that the two symmetries enter as a direct product, in agreement with the Coleman-Mandula theorem.

  16. Gauge symmetry from decoupling

    NASA Astrophysics Data System (ADS)

    Wetterich, C.

    2017-02-01

    Gauge symmetries emerge from a redundant description of the effective action for light degrees of freedom after the decoupling of heavy modes. This redundant description avoids the use of explicit constraints in configuration space. For non-linear constraints the gauge symmetries are non-linear. In a quantum field theory setting the gauge symmetries are local and can describe Yang-Mills theories or quantum gravity. We formulate gauge invariant fields that correspond to the non-linear light degrees of freedom. In the context of functional renormalization gauge symmetries can emerge if the flow generates or preserves large mass-like terms for the heavy degrees of freedom. They correspond to a particular form of gauge fixing terms in quantum field theories.

  17. The Symmetries of QCD

    ScienceCinema

    Sekhar Chivukula

    2016-07-12

    The symmetries of a quantum field theory can be realized in a variety of ways. Symmetries can be realized explicitly, approximately, through spontaneous symmetry breaking or, via an anomaly, quantum effects can dynamically eliminate a symmetry of the theory that was present at the classical level.  Quantum Chromodynamics (QCD), the modern theory of the strong interactions, exemplify each of these possibilities. The interplay of these effects determine the spectrum of particles that we observe and, ultimately, account for 99% of the mass of ordinary matter. 

  18. Animal Gaits and Symmetry

    NASA Astrophysics Data System (ADS)

    Golubitsky, Martin

    2012-04-01

    Many gaits of four-legged animals are described by symmetry. For example, when a horse paces it moves both left legs in unison and then both right legs and so on. The motion is described by two symmetries: Interchange front and back legs, and swap left and right legs with a half-period phase shift. Biologists postulate the existence of a central pattern generator (CPG) in the neuronal system that sends periodic signals to the legs. CPGs can be thought of as electrical circuits that produce periodic signals and can be modeled by systems with symmetry. In this lecture we discuss animal gaits; use gait symmetries to construct a simplest CPG architecture that naturally produces quadrupedal gait rhythms; and make several testable predictions about gaits.

  19. Changes in [(3)H]-ouabain and [(3)H]-neurotensin binding to rat cerebral cortex membranes after administration of antipsychotic drugs haloperidol and clozapine.

    PubMed

    Rosin, Carina; López Ordieres, María Graciela; Rodríguez de Lores Arnaiz, Georgina

    2017-03-01

    Evidences indicate the relationship between neurotensinergic and dopaminergic systems. Neurotensin inhibits synaptosomal membrane Na(+), K(+)-ATPase activity, an effect blocked by SR 48692, antagonist for high affinity neurotensin receptor (NTS1) type. Assays of high affinity [(3)H]-ouabain binding (to analyze K(+) site of Na(+), K(+)-ATPase) show that in vitro addition of neurotensin decreases binding. Herein potential interaction between NTS1 receptor, dopaminergic D2 receptor and Na(+), K(+)-ATPase was studied. To test the involvement of dopaminergic D2 receptors in [(3)H]-ouabain binding inhibition by neurotensin, Wistar rats were administered i.p.with antipsychotic drugs haloperidol (2mg/kg) and clozapine (3, 10 and 30mg/kg). Animals were sacrificed 18h later, cerebral cortices harvested, membrane fractions prepared and high affinity [(3)H]-ouabain binding assayed in the absence or presence of neurotensin at a 10 micromolar concentration. No differences versus controls for basal binding or for binding inhibition by neurotensin were recorded, except after 10mg/kg clozapine. Rats were administered with neurotensin (3, 10y 30μg, i.c.v.) and 60min later, animals were sacrificed, cerebral cortices harvested and processed to obtain membrane fractions for high affinity [(3)H]-ouabain binding assays. Results showed a slight but statistically significant decrease in binding with the 30μg neurotensin dose. To analyze the interaction between dopaminergic D2 and NTS1 receptors, [(3)H]-neurotensin binding to cortical membranes from rats injected with haloperidol (2mg/kg, i.p.) or clozapine (10mg/kg) was assayed. Saturation curves and Scatchard transformation showed that the only statistically significant change occurred in Bmax after haloperidol administration. Hill number was close to the unit in all cases. Results indicated that typical and atypical antipsychotic drugs differentially modulate the interaction between neurotensin and Na(+), K(+)-ATPase. At the same time

  20. X-ray and neutron powder diffraction analyses of Gly·MgSO4·5H2O and Gly·MgSO4·3H2O, and their deuterated counterparts.

    PubMed

    Howard, Christopher; Wood, Ian G; Knight, Kevin S; Fortes, A Dominic

    2016-03-01

    We have identified a new compound in the glycine-MgSO4-water ternary system, namely glycine magnesium sulfate trihydrate (or Gly·MgSO4·3H2O) {systematic name: catena-poly[[tetraaquamagnesium(II)]-μ-glycine-κ(2)O:O'-[diaquabis(sulfato-κO)magnesium(II)]-μ-glycine-κ(2)O:O']; [Mg(SO4)(C2D5NO2)(D2O)3]n}, which can be grown from a supersaturated solution at ∼350 K and which may also be formed by heating the previously known glycine magnesium sulfate pentahydrate (or Gly·MgSO4·5H2O) {systematic name: hexaaquamagnesium(II) tetraaquadiglycinemagnesium(II) disulfate; [Mg(D2O)6][Mg(C2D5NO2)2(D2O)4](SO4)2} above ∼330 K in air. X-ray powder diffraction analysis reveals that the trihydrate phase is monoclinic (space group P21/n), with a unit-cell metric very similar to that of recently identified Gly·CoSO4·3H2O [Tepavitcharova et al. (2012). J. Mol. Struct. 1018, 113-121]. In order to obtain an accurate determination of all structural parameters, including the locations of H atoms, and to better understand the relationship between the pentahydrate and the trihydrate, neutron powder diffraction measurements of both (fully deuterated) phases were carried out at 10 K at the ISIS neutron spallation source, these being complemented with X-ray powder diffraction measurements and Raman spectroscopy. At 10 K, glycine magnesium sulfate pentahydrate, structurally described by the `double' formula [Gly(d5)·MgSO4·5D2O]2, is triclinic (space group P-1, Z = 1), and glycine magnesium sulfate trihydrate, which may be described by the formula Gly(d5)·MgSO4·3D2O, is monoclinic (space group P21/n, Z = 4). In the pentahydrate, there are two symmetry-inequivalent MgO6 octahedra on sites of -1 symmetry and two SO4 tetrahedra with site symmetry 1. The octahedra comprise one [tetraaquadiglcyinemagnesium](2+) ion (centred on Mg1) and one [hexaaquamagnesium](2+) ion (centred on Mg2), and the glycine zwitterion, NH3(+)CH2COO(-), adopts a monodentate coordination to Mg2. In the

  1. Dopamine denervation does not alter in vivo /sup 3/H-spiperone binding in rat striatum: implications for external imaging of dopamine receptors in Parkinson's disease

    SciTech Connect

    Bennett, J.P. Jr.; Wooten, G.F.

    1986-04-01

    Striatal particulate preparations, both from rats with lesion-induced striatal dopamine (DA) loss and from some striatal dopamine (DA) loss and from some patients with Parkinson's disease, exhibit increased /sup 3/H-neuroleptic binding, which is interpreted to be the mechanism of denervation-induced behavioral supersensitivity to dopaminergic compounds. After intravenous /sup 3/H-spiperone (/sup 3/H-SP) administration to rats with unilateral nigral lesions, we found no differences in accumulation of total or particulate-bound /sup 3/H-SP in dopamine-denervated compared with intact striata. /sup 3/H-SP in vivo binds to less than 10% of striatal sites labeled by /sup 3/H-SP incubated with striatal particulate preparations in vitro. Quantitative autoradiography of /sup 3/H-SP binding to striatal sections in vitro also failed to reveal any effects of dopamine denervation. /sup 3/H-SP bound to striatal sites in vivo dissociates more slowly than that bound to striatal particulate preparations labeled in vitro. Striatal binding properties of /sup 3/H-SP administered in vivo are quite different from the same kinetic binding parameters estimated in vitro using crude membrane preparations of striatum. In addition, striatal binding of in vivo-administered 3H-SP is not affected by prior lesion of the substantia nigra, which results in profound ipsilateral striatal dopamine depletion. Thus, behavioral supersensitivity to dopaminergic compounds may not be associated with altered striatal binding properties for dopamine receptor ligands in vivo.

  2. [3H]Methotrexate as a ligand for the folate receptor of Dictyostelium discoideum.

    PubMed Central

    Nandini-Kishore, S G; Frazier, W A

    1981-01-01

    Studies of the folate chemotactic receptor of vegetative Dictyostelium discoideum cells have been hampered by the presence of the degradative enzyme folate deaminase. The diaminopterin compounds aminopterin and methotrexate (MTX) are chemoattractants but are not attacked by the deaminase. [3',5',7,9-3H]methotrexate ([3H]MTX) is a nondegraded radioligand for the folate receptor. Binding to the receptor is rapid, reaching steady state in less than one min, and reversible in less than 15 s by an excess of unlabeled MTX. A single class of binding sites is found with a Kd of 2 x 10(-8) M, which correlates well with the concentration dependence of chemotaxis. Folate, aminopterin, and MTX all compete for [3H]MTX binding, whereas pterin, p-aminobenzoate, and nucleotides do not. Analysis of the receptor during differentiation indicates a decrease in site number by a factor of 3 with no change in affinity during the first 7 hr. During this time, the directional response (chemotaxis) to MTX and folate is lost, but a nondirectional stimulation of motility rate (chemokinesis) is retained. The response to cyclic AMP displays reciprocal behavior, first appearing as a chemokinetic response and then as a chemotactic response. PMID:6278468

  3. Calculated photoelectron spectra of isotopomers of the propargyl radical (H 2C 3H): An explicitly correlated coupled cluster study

    NASA Astrophysics Data System (ADS)

    Botschwina, Peter; Oswald, Rainer

    2010-12-01

    Explicitly correlated coupled cluster theory at the (U)CCSD(T∗)-F12a level has been employed to study the vibrational structure of the first two bands of the low-temperature photoelectron spectra of four different isotopomers of the propargyl radical with C 2v symmetry (H 2C 3H, H 2C 3D, D 2C 3H, and D 2C 3D). A five-dimensional anharmonic model is employed to calculate the peak positions and relative intensities. While the first band of the PE spectra of all four isotopomers is dominated by the adiabatic peak, the second band shows a progression in the pseudoantisymmetric CC stretching vibration v3 with relative intensities of 100:68:23:5:1 for n = 0-4 in the case of the most abundant isotopomer.

  4. Quantum Spectral Symmetries

    NASA Astrophysics Data System (ADS)

    Hamhalter, Jan; Turilova, Ekaterina

    2017-02-01

    Quantum symmetries of spectral lattices are studied. Basic properties of spectral order on A W ∗-algebras are summarized. Connection between projection and spectral automorphisms is clarified by showing that, under mild conditions, any spectral automorphism is a composition of function calculus and Jordan ∗-automorphism. Complete description of quantum spectral symmetries on Type I and Type II A W ∗-factors are completely described.

  5. Imipramine treatment differentially affects platelet /sup 3/H-imipramine binding and serotonin uptake in depressed patients

    SciTech Connect

    Suranyi-Cadotte, B.E.; Quirion, R.; Nair, N.P.V.; Lafaille, F.; Schwartz, G.

    1985-02-25

    Uptake of serotonin and /sup 3/H-imipramine binding in platelets of depressed patients were investigated simultaneously with changes in clinical state. Both V/sub max/ for serotonin uptake and B/sub max/ for /sup 3/H-imipramine binding were significantly lower in unmedicated depressed patients with respect to normal subjects. Successful treatment with imipramine led to a significant increase in B/sub max/ for /sup 3/H-imipramine binding, without significant change in V/sub max/ for serotonin uptake. B/sub max/ values increased to the normal range following complete, rather than partial clinical improvement. These data indicate that successful antidepressant treatment may increase the density of /sup 3/H-imipramine binding sites on platelets by a process which is independent of the uptake of serotonin. 29 references, 1 table.

  6. The nuclear symmetry energy

    NASA Astrophysics Data System (ADS)

    Baldo, M.; Burgio, G. F.

    2016-11-01

    The nuclear symmetry energy characterizes the variation of the binding energy as the neutron to proton ratio of a nuclear system is varied. This is one of the most important features of nuclear physics in general, since it is just related to the two component nature of the nuclear systems. As such it is one of the most relevant physical parameters that affect the physics of many phenomena and nuclear processes. This review paper presents a survey of the role and relevance of the nuclear symmetry energy in different fields of research and of the accuracy of its determination from the phenomenology and from the microscopic many-body theory. In recent years, a great interest was devoted not only to the Nuclear Matter symmetry energy at saturation density but also to its whole density dependence, which is an essential ingredient for our understanding of many phenomena. We analyze the nuclear symmetry energy in different realms of nuclear physics and astrophysics. In particular we consider the nuclear symmetry energy in relation to nuclear structure, astrophysics of Neutron Stars and supernovae, and heavy ion collision experiments, trying to elucidate the connections of these different fields on the basis of the symmetry energy peculiarities. The interplay between experimental and observational data and theoretical developments is stressed. The expected future developments and improvements are schematically addressed, together with most demanded experimental and theoretical advances for the next few years.

  7. (3H)WB4101 labels the 5-HT1A serotonin receptor subtype in rat brain. Guanine nucleotide and divalent cation sensitivity

    SciTech Connect

    Norman, A.B.; Battaglia, G.; Creese, I.

    1985-12-01

    In the presence of a 30 nM prazosin mask, (/sup 3/H)-2-(2,6-dimethoxyphenoxyethyl) aminomethyl-1,4-benzodioxane ((/sup 3/H)WB4101) can selectively label 5-HT1 serotonin receptors. Serotonin exhibits high affinity (Ki = 2.5 nM) and monophasic competition for (/sup 3/H) WB4101 binding in cerebral cortex. We have found a significant correlation (r = 0.96) between the affinities of a number of serotonergic and nonserotonergic compounds at (/sup 3/H)WB4101-binding sites in the presence of 30 nM prazosin and (/sup 3/H) lysergic acid diethylamide ((/sup 3/H)LSD)-labeled 5-HT1 serotonin receptors in homogenates of rat cerebral cortex. Despite similar pharmacological profiles, distribution studies indicate that, in the presence of 5 mM MgSO4, the Bmax of (/sup 3/H)WB4101 is significantly lower than the Bmax of (/sup 3/H)LSD in various brain regions. WB4101 competition for (/sup 3/H) LSD-labeled 5-HT1 receptors fits best to a computer-derived model assuming two binding sites, with the KH for WB4101 being similar to the KD of (/sup 3/H)WB4101 binding derived from saturation experiments. This suggests that (/sup 3/H)WB4101 labels only one of the subtypes of the 5-HT1 serotonin receptors labeled by (/sup 3/H)LSD. The selective 5-HT1A serotonin receptor antagonist, spiperone, and the selective 5-HT1A agonist, 8-hydroxy-2-(di-n-propylamino) tetraline, exhibit high affinity and monophasic competition for (/sup 3/H)WB4101 but compete for multiple (/sup 3/H)LSD 5-HT1 binding sites. These data indicate that (/sup 3/H)WB4101 selectively labels the 5-HT1A serotonin receptor, whereas (/sup 3/H) LSD appears to label both the 5-HT1A and the 5-HT1B serotonin receptor subtypes. The divalent cations, Mn2+, Mg2+, and Ca2+ were found to markedly increase the affinity and Bmax of (/sup 3/H)WB4101 binding in cerebral cortex. Conversely, the guanine nucleotides guanylylimidodiphosphate and GTP, but not the adenosine nucleotide ATP, markedly reduce the Bmax of (/sup 3/H)WB4101 binding.

  8. Silver-Catalyzed C(sp(3))-H Chlorination.

    PubMed

    Ozawa, Jun; Kanai, Motomu

    2017-03-17

    A silver-catalyzed chlorination of benzylic, tertiary, and secondary C(sp(3))-H bonds was developed. The reaction proceeded with as low as 0.2 mol % catalyst loading at room temperature under air atmosphere with synthetically useful functional group compatibility. The regioselectivity and reactivity tendencies suggest that the chlorination proceeded through a radical pathway, but an intermediate alkylsilver species cannot be ruled out.

  9. In vivo labeling of phencyclidine (PCP) receptors with sup 3 H-TCP in the mouse brain

    SciTech Connect

    Maurice, T.; Vignon, J. )

    1990-07-01

    The phencyclidine (PCP) derivative N-(1-(2-thienyl)cyclohexyl)-piperidine (3H-TCP) was used to label in vivo the N-methyl-D-aspartate (NMDA) receptor-associated ionic channel in the mouse brain. After the injection of a tracer dose of 3H-TCP, a spread labeling throughout the brain was observed, but was the highest in the cerebellum. Preadministration of unlabeled TCP (30 mg/kg) resulted in a 90% reduction of 3H-TCP binding. PCP, TCP, MK-801, dexoxadrol, ketamine, and SKF 10,047 isomers dose-dependently prevented the in vivo 3H-TCP binding. ID50 determined in the cerebrum and the cerebellum were respectively correlated with K0.5 for 3H TCP high (rat cortex) and low affinity (rat cerebellum) sites in vitro. The pharmacological specificity of the 3H-TCP binding site in the cerebellum was significantly different from that in the cerebrum. ID50 values were generally higher than in the cerebrum and, particularly, MK-801, the most potent drug in the cerebrum, was without significant effect in the cerebellum, at any time and at doses as high as 30 mg/kg. N-(1-(2-benzo(b) thiophenyl)cyclohexyl)piperidine (BTCP), desipramine, and atropine showed a more efficient prevention of 3H-TCP binding in the cerebellum than in the cerebrum. The prevention of the binding by TCP or PCP, at doses close to their ID50 values, was rapid and then decreased slowly. The effect of MK-801 was long-lasting. This study confirm previous in vitro studies: 3H-TCP is an efficient tool for the labeling of the NMDA receptor-associated ionic channel.

  10. Preformance Analysis of NH3-H2O Absorption Cycle

    NASA Astrophysics Data System (ADS)

    Tsujimori, Atsushi; Ozaki, Eiichi

    Different from H2O-LiBr absorption cycle, it is necessary to have rectifier between generator and condenser in NH3-H2O absorption cycle, because there mixes some steam in refrigerant vapor in the process of regenerating refrigerant from the ammonia strong aqueous solution. And in some case ex. partial load or heating, the efficiency of rectifier might decrease, if the flow rate of refrigerant vapor and ammonia aqueous solution decrease. As a result, steam flow into condenser with ammonia refrigerant vapor, which reduces cycle COPs of cooling and heating. Accordingly in order to evaluate the effect of ammonia concentration in refrigerant for the performance of NH3-H2O absorption heat pump, the simple design approach of modeling condenser and evaporator is introduced in this paper. In the model, the calculation of heat rate in condenser and evaporator was simplified considering the characteristic of NH3-H2O liquid-vapor equilibrium. Then the simulation for cycle perforance based on GAX absorption cycle was made using the efficiency of rectifier that established the ammonia concentration in refrigerant and it was derived that 3 [%] decrease of ammonia concentration in refrigerant induced 15 [%] decrcase of cooling COP and 7 [%] decrease of heating COP and that there existed the most suitable circulation ratio for each ammonia concentration in refrigerant.

  11. Preservation of peripheral benzodiazepine receptors: differential effects of freezing on (/sup 3/H)Ro 5-4864 and (3H)PK 11195 binding

    SciTech Connect

    Basile, A.S.; Ostrowski, N.L.; Skolnick, P.

    1987-04-01

    A statistically significant decrease in the density of peripheral benzodiazepine receptors was observed in renal membranes of rats beginning 2 weeks after adrenalectomy when compared with sham-operated controls. This decrease in peripheral benzodiazepine receptor density was manifest as a decrease in the Bmax of two ligands (/sup 3/H)Ro 5-4864 and (/sup 3/H)PK 11195, without accompanying changes in their apparent affinity (Kd) for this site. Similar changes were not seen in another aldosterone-sensitive organ, the submandibular salivary gland. The decrease in peripheral benzodiazepine receptor density in observed in adrenalectomized rat renal membranes was restored to control levels after 1 week of aldosterone administration using a dose (12.5 micrograms/kg/day) that had no effect on peripheral benzodiazepine receptor density in sham-operated animals. In contrast, dexamethasone administration (50 micrograms/kg/day, 1 week) had no effect on renal peripheral benzodiazepine receptor density when administered to either adrenalectomized or sham-operated rats. Further, adrenal demedullation had no effect on renal peripheral benzodiazepine receptor density or affinity. The decrease in peripheral benzodiazepine receptor density was localized to the renal cortex and the outer stripe of the medulla by gross dissection of renal slices and renal tissue section autoradiography. The specific effect of adrenalectomy on renal peripheral benzodiazepine receptor density, the lack of direct effect of aldosterone on (/sup 3/H)Ro 5-4864 binding, and the localization of the change in peripheral benzodiazepine receptor density to the renal cortex and outer stripe suggests that these changes may reflect an adaptation of the renal nephron (possibly the distal convoluted tubule, intermediate tubule and/or the collecting duct) to the loss of mineralocorticoid hormones.

  12. New symmetry of the cluster model

    NASA Astrophysics Data System (ADS)

    Gai, Moshe

    2015-10-01

    A new approach to clustering in the frame of the Algebraic Cluster Model (ACM) has been developed. It predicts rotation-vibration structure with rotational band of an oblate equilateral triangular spinning top with a 𝒟3h symmetry characterized by the sequence of states: 0+, 2+, 3-, 4±, 5- with almost degenerate 4+ and 4- (parity doublet) states. Our measurement of the new 22+ and the measured of the new 5- state in 12C fit very well to the predicted (ground state) rotational band structure with the sequence of states: 0+, 2+, 3-, 4±, 5- with almost degenerate 4+ and 4- (parity doublet) states. Such a 𝒟3h symmetry was observed in triatomic molecules, and it is observed in 12C for the first time in nuclear physics. We discuss a classification of other rotation-vibration bands in 12C such as the (0+) Hoyle band and the (1-) bending mode band and suggest measurements in search of the predicted ("missing") states that may shed new light on clustering in 12C and light nuclei. In particular, the observation (or non observation) of the predicted ("missing") states in the Hoyle band will allow us to conclude the geometrical arrangement of the three alpha particles composing the Hoyle state at 7.654 MeV in 12C.

  13. Elevation of naloxone-sensitive /sup 3/H-dihydromorphine binding in hippocampal formation of genetically epilepsy-prone rats

    SciTech Connect

    Savage, D.D.; Mills, S.A.; Jobe, P.C.; Reigel, C.E.

    1988-01-01

    /sup 3/H-Dihydromorphine (DHM) binding sites were measured in the brain of non-epileptic control and GEPR rats using in vitro autoradiographic techniques. The number of naloxone-sensitive /sup 3/H-DHM binding sites was increased 38-57% in the pyramidal cell layer of ventral hippocampal CA/sub 3/ and CA/sub 1/ of GEPR-3 and GEPR-9 rats compared to non-epileptic controls. No significant differences in /sup 3/H-DHM binding were observed in dorsal hippocampal formation, lateral entorhinal cortex, lateral geniculate or cerebellum. The results suggest that an increase in the number of opioid receptors in ventral hippocampus of GEPR rats may be one factor contributing to the enhanced sensitivity of GEPR-9 rats to the proconvulsant effects of morphine.

  14. Lectures on Yangian symmetry

    NASA Astrophysics Data System (ADS)

    Loebbert, Florian

    2016-08-01

    In these introductory lectures we discuss the topic of Yangian symmetry from various perspectives. Forming the classical counterpart of the Yangian and an extension of ordinary Noether symmetries, first the concept of nonlocal charges in classical, two-dimensional field theory is reviewed. We then define the Yangian algebra following Drinfel’d's original motivation to construct solutions to the quantum Yang-Baxter equation. Different realizations of the Yangian and its mathematical role as a Hopf algebra and quantum group are discussed. We demonstrate how the Yangian algebra is implemented in quantum, two-dimensional field theories and how its generators are renormalized. Implications of Yangian symmetry on the two-dimensional scattering matrix are investigated. We furthermore consider the important case of discrete Yangian symmetry realized on integrable spin chains. Finally we give a brief introduction to Yangian symmetry in planar, four-dimensional super Yang-Mills theory and indicate its impact on the dilatation operator and tree-level scattering amplitudes. These lectures are illustrated by several examples, in particular the two-dimensional chiral Gross-Neveu model, the Heisenberg spin chain and { N }=4 superconformal Yang-Mills theory in four dimensions.

  15. Symmetry of priapulids (Priapulida). 2. Symmetry of larvae.

    PubMed

    Adrianov, A V; Malakhov, V V

    2001-02-01

    Larvae of priapulids are characterized by radial symmetry evident from both external and internal characters of the introvert and lorica. The bilaterality appears as a result of a combination of several radial symmetries: pentaradial symmetry of the teeth, octaradial symmetry of the primary scalids, 25-radial symmetry of scalids, biradial symmetry of the neck, and biradial and decaradial symmetry of the trunk. Internal radiality is exhibited by musculature and the circumpharyngeal nerve ring. Internal bilaterality is evident from the position of the ventral nerve cord and excretory elements. Externally, the bilaterality is determined by the position of the anal tubulus and two shortened midventral rows of scalids bordering the ventral nerve cord. The lorical elements define the biradial symmetry that is missing in adult priapulids. The radial symmetry of larvae is a secondary appearance considered an evolutionary adaptation to a lifestyle within the three-dimensional environment of the benthic sediment.

  16. Symmetry in context: salience of mirror symmetry in natural patterns.

    PubMed

    Cohen, Elias H; Zaidi, Qasim

    2013-05-31

    Symmetry is a biologically relevant, mathematically involving, and aesthetically compelling visual phenomenon. Mirror symmetry detection is considered particularly rapid and efficient, based on experiments with random noise. Symmetry detection in natural settings, however, is often accomplished against structured backgrounds. To measure salience of symmetry in diverse contexts, we assembled mirror symmetric patterns from 101 natural textures. Temporal thresholds for detecting the symmetry axis ranged from 28 to 568 ms indicating a wide range of salience (1/Threshold). We built a model for estimating symmetry-energy by connecting pairs of mirror-symmetric filters that simulated cortical receptive fields. The model easily identified the axis of symmetry for all patterns. However, symmetry-energy quantified at this axis correlated weakly with salience. To examine context effects on symmetry detection, we used the same model to estimate approximate symmetry resulting from the underlying texture throughout the image. Magnitudes of approximate symmetry at flanking and orthogonal axes showed strong negative correlations with salience, revealing context interference with symmetry detection. A regression model that included the context-based measures explained the salience results, and revealed why perceptual symmetry can differ from mathematical characterizations. Using natural patterns thus produces new insights into symmetry perception and its possible neural circuits.

  17. Symmetry in context: Salience of mirror symmetry in natural patterns

    PubMed Central

    Cohen, Elias H.; Zaidi, Qasim

    2013-01-01

    Symmetry is a biologically relevant, mathematically involving, and aesthetically compelling visual phenomenon. Mirror symmetry detection is considered particularly rapid and efficient, based on experiments with random noise. Symmetry detection in natural settings, however, is often accomplished against structured backgrounds. To measure salience of symmetry in diverse contexts, we assembled mirror symmetric patterns from 101 natural textures. Temporal thresholds for detecting the symmetry axis ranged from 28 to 568 ms indicating a wide range of salience (1/Threshold). We built a model for estimating symmetry-energy by connecting pairs of mirror-symmetric filters that simulated cortical receptive fields. The model easily identified the axis of symmetry for all patterns. However, symmetry-energy quantified at this axis correlated weakly with salience. To examine context effects on symmetry detection, we used the same model to estimate approximate symmetry resulting from the underlying texture throughout the image. Magnitudes of approximate symmetry at flanking and orthogonal axes showed strong negative correlations with salience, revealing context interference with symmetry detection. A regression model that included the context-based measures explained the salience results, and revealed why perceptual symmetry can differ from mathematical characterizations. Using natural patterns thus produces new insights into symmetry perception and its possible neural circuits. PMID:23729773

  18. Human kidney thiopurine methyltransferase (TPMT): Photoaffinity labeling with ( sup 3 H-methyl)- S-adenosyl-L-methionine ( sup 3 H-ado-met)

    SciTech Connect

    Van Loon, J.A.; Weinshilboum, R.M. )

    1990-02-26

    TPMT (EC 2.1.1.67) catalyzes the S-methylation of 6-mercaptopurine (6-MP) and other heterocyclic and aromatic thiol drugs. TPMT activity and immunoreactive protein in humans are regulated by a common genetic polymorphism. Human kidney contains two isozymes of TPMT which can be separated by ion exchange chromatography. Partially purified isozymes of human kidney TPMT were exposed to UV light in the presence of {sup 3}H-Ado-Met. After photolysis, these preparations were subjected to SDS-polyacrylamide gel electrophoresis. Autoradiography of gels revealed that a 34 kDa protein was the predominant species that was radioactively labeled for both isozymes. Photoaffinity labeling of TPMT was inhibited in a concentration-dependent fashion by the methyl acceptor substrate, 6-MP, and by three TPMT inhibitors, 3,4-dimethoxy-5-hydroxybenzoic acid, 6-methylmercaptopurine and S-adenosyl-L-homocysteine. Of three wavelengths tested, 254, 300, and 350 nm, labeling was the greatest at 254 nm, near the absorption maximum for Ado-Met. Photoaffinity labeling of TPMT with {sup 3}H-Ado-Met should make it possible to determine the amino acid sequence of the active site and may make it possible to define the molecular basis of the genetic polymorphism for this important drug-metabolizing enzyme.

  19. A LABORATORY STUDY OF C{sub 3}H{sup +} AND THE C{sub 3}H RADICAL IN THREE NEW VIBRATIONALLY EXCITED {sup 2}Σ STATES USING A PIN-HOLE NOZZLE DISCHARGE SOURCE

    SciTech Connect

    McCarthy, Michael C.; Crabtree, Kyle N.; Martin-Drumel, Marie-Aline; Martinez, Oscar Jr.; Gottlieb, Carl A.; McGuire, Brett A.

    2015-03-15

    Rotational lines of the positive molecular ion C{sub 3}H{sup +} and of the neutral C{sub 3}H radical in three new vibrationally excited states with {sup 2}Σ symmetry have been detected in a supersonic molecular beam in the centimeter-wave band. The fundamental rotational line of the ion is quite weak, but is observed with similar intensity in a dc discharge through several different hydrocarbon gases when helium is the buffer gas. Under these conditions, the fractional abundance of C{sub 3}H{sup +} relative to C{sub 3}H is estimated to be of order 10{sup −4}, i.e., toward the lower end of the ratio (10{sup −3}–10{sup −4}) found for protonated ions using the same discharge nozzle. For each new {sup 2}Σ state of the C{sub 3}H radical, spectroscopic constants, including those describing hydrogen hyperfine structure, have been determined to high precision. Lines of one {sup 2}Σ state (B = 11271 MHz) are particularly intense in our molecular beam; for this state and a second one (B = 11306 MHz), millimeter-wave transitions have also been observed between 180 and 340 GHz using a long path dc glow absorption spectrometer. On the basis of intensity measurements with this spectrometer, the inferred rotation–vibration constant α, and theoretical calculations, the state with B = 11271 MHz is tentatively assigned to the ν{sub 5} bending mode, predicted to lie ∼300 cm{sup −1} above ground.

  20. The radioactivity estimation of 14C and 3H in graphite waste samples of the KRR-2.

    PubMed

    Reyoung Kim, Hee

    2013-09-01

    The radioactivity of (14)C and (3)H in graphite samples from the dismantled Korea Research Reactor-2 (the KRR-2) site was analyzed by high-temperature oxidation and liquid scintillation counting, and the graphite waste was suggested to be disposed of as a low-level radioactive waste. The graphite samples were oxidized at a high temperature of 800 °C, and their counting rates were measured by using a liquid scintillation counter (LSC). The combustion ratio of the graphite was about 99% on the sample with a maximum weight of 1g. The recoveries from the combustion furnace were around 100% and 90% in (14)C and (3)H, respectively. The minimum detectable activity was 0.04-0.05 Bq/g for the (14)C and 0.13-0.15 Bq/g for the (3)H at the same background counting time. The activity of (14)C was higher than that of (3)H over all samples with the activity ratios of the (14)C to (3)H, (14)C/(3)H, being between 2.8 and 25. The dose calculation was carried out from its radioactivity analysis results. The dose estimation gave a higher annual dose than the domestic legal limit for a clearance. It was thought that the sampled graphite waste from the dismantled research reactor was not available for reuse or recycling and should be monitored as low-level radioactive waste.

  1. Temporal pattern of incorporation of /sup 3/H precursors into pituitary glycoproteins and their subsequent release

    SciTech Connect

    Grotjan, H.E. Jr.

    1982-04-01

    The temporal pattern of incorporation of various /sup 3/H precursors into glycoproteins by rat anterior pituitaries incubated in vitro and the release of /sup 3/H-glycoproteins was examined. (/sup 3/H)Leucine incorporation was linear with respect to time and (/sup 3/H)leucine-containing macromolecules appeared in the media in about 1 hr. The temporal pattern of (/sup 3/H)mannose incorporation and release was similar. (/sup 3/H)Galactose and (/sup 3/H)fucose were incorporated after apparent time of delays of approximately 15 min and soon thereafter (20-25 min) appeared in the medium in /sup 3/H-glycoproteins. Thus, these precursors appear to be added as terminal residues. (/sup 3/H)Glucosamine exhibited a pattern intermediate between (/sup 3/H)leucine and (/sup 3/H)fucose whereas (/sup 3/H)GlcNAc appeared to be incorporated as a terminal residue.

  2. Quantitative tritium exchange of (/sup 3/H) aflatoxin B1 during penetration through isolated human skin

    SciTech Connect

    Riley, R.T.; Kemppainen, B.W.; Norred, W.P.

    1988-05-31

    Tritium labelled aflatoxin B1 ((G-/sup 3/H)AFB1) underwent an almost total tritium exchange with water during penetration through isolated human skin. The process was not enzymatic and the site of exchange appeared to be within the epidermis. The mechanism which mediated this extensive exchange was not determined. However, the tritium in (G-/sup 3/H)AFB1 was found to be very susceptible to chemical conditions which favored carbanion formation at the alpha-carbon of the cyclopentenone ring. The relative effectiveness of the various solvents in mediating the loss of the tritium label was 1 N/sub 3/NaOH much greater than methanol greater than 1 N HCl greater than water. This work serves as a warning that (G-/sup 3/H)AFB1 can easily undergo significant changes in specific activity in biological tissues and under relatively mild experimental conditions. It is possible that conditions within the skin favor carbanion formation.

  3. Binding of (/sup 3/H)Forskolin to rat brain membranes

    SciTech Connect

    Seamon, K.B.; Vaillancourt, R.; Edwards, M.; Daly, J.W.

    1984-08-01

    (12-/sup 3/H)Forskolin (27 Ci/mmol) has been used to study binding sites in rat brain tissue by using both centrifugation and filtration assays. The binding isotherm measured in the presence of 5 mM MgCl/sub 2/ by using the centrifugation assay is described best by a two-site model: K/sub d1/ = 15 nM, B/sub max/sub 1// (maximal binding) = 270 fmol/mg of protein; K/sub d2/ = 1.1 ..mu..M; B/sub max/sub 2// = 4.2 pmol/mg of protein. Only the high-affinity binding sites are detected when the binding is determined by using a filtration assay; K/sub d/ = 26 nM, B/sub max/ = 400 fmol/mg of protein. Analogs of forskolin that do not activate adenylate cyclase (EC 4.6.1.1) do not compete effectively for (/sup 3/H)forskolin binding sites. Analogs of forskolin that are less potent than forskolin in activating adenylate cyclase are also less potent in competing for forskolin binding sites. The presence of 5 mM MgCl/sub 2/ or MnCl/sub 2/ was found to enhance binding. In the presence of 1 mM EDTA the amount of high-affinity binding is reduced to 110 fmol/mg of protein with no change in K/sub d/. There is no effect of CaCl/sub 2/ (20 mM) or NaCl (100 mM) on the binding. No high-affinity binding can be detected in membranes from ram sperm, which contains an adenylate cyclase that is not activated by forskolin. It is proposed that the high-affinity binding sites for forskolin are associated with the activated complex of catalytic subunit and stimulatory guanine nucleotide binding protein. 23 references, 5 figures, 2 tables.

  4. Weakly broken galileon symmetry

    SciTech Connect

    Pirtskhalava, David; Santoni, Luca; Trincherini, Enrico; Vernizzi, Filippo

    2015-09-01

    Effective theories of a scalar ϕ invariant under the internal galileon symmetryϕ→ϕ+b{sub μ}x{sup μ} have been extensively studied due to their special theoretical and phenomenological properties. In this paper, we introduce the notion of weakly broken galileon invariance, which characterizes the unique class of couplings of such theories to gravity that maximally retain their defining symmetry. The curved-space remnant of the galileon’s quantum properties allows to construct (quasi) de Sitter backgrounds largely insensitive to loop corrections. We exploit this fact to build novel cosmological models with interesting phenomenology, relevant for both inflation and late-time acceleration of the universe.

  5. Baryons and chiral symmetry

    NASA Astrophysics Data System (ADS)

    Liu, Keh-Fei

    The relevance of chiral symmetry in baryons is highlighted in three examples in the nucleon spectroscopy and structure. The first one is the importance of chiral dynamics in understanding the Roper resonance. The second one is the role of chiral symmetry in the lattice calculation of πNσ term and strangeness. The third one is the role of chiral U(1) anomaly in the anomalous Ward identity in evaluating the quark spin and the quark orbital angular momentum. Finally, the chiral effective theory for baryons is discussed.

  6. BOOK REVIEW: Symmetry Breaking

    NASA Astrophysics Data System (ADS)

    Ryder, L. H.

    2005-11-01

    One of the most fruitful and enduring advances in theoretical physics during the last half century has been the development of the role played by symmetries. One needs only to consider SU(3) and the classification of elementary particles, the Yang Mills enlargement of Maxwell's electrodynamics to the symmetry group SU(2), and indeed the tremendous activity surrounding the discovery of parity violation in the weak interactions in the late 1950s. This last example is one of a broken symmetry, though the symmetry in question is a discrete one. It was clear to Gell-Mann, who first clarified the role of SU(3) in particle physics, that this symmetry was not exact. If it had been, it would have been much easier to discover; for example, the proton, neutron, Σ, Λ and Ξ particles would all have had the same mass. For many years the SU(3) symmetry breaking was assigned a mathematical form, but the importance of this formulation fell away when the quark model began to be taken seriously; the reason the SU(3) symmetry was not exact was simply that the (three, in those days) quarks had different masses. At the same time, and in a different context, symmetry breaking of a different type was being investigated. This went by the name of `spontaneous symmetry breaking' and its characteristic was that the ground state of a given system was not invariant under the symmetry transformation, though the interactions (the Hamiltonian, in effect) was. A classic example is ferromagnetism. In a ferromagnet the atomic spins are aligned in one direction only—this is the ground state of the system. It is clearly not invariant under a rotation, for that would change the ground state into a (similar but) different one, with the spins aligned in a different direction; this is the phenomenon of a degenerate vacuum. The contribution of the spin interaction, s1.s2, to the Hamiltonian, however, is actually invariant under rotations. As Coleman remarked, a little man living in a ferromagnet would

  7. Thermodynamic Modeling of the SRS Evaporators: Part II. The 3H System

    SciTech Connect

    Jantzen, C.M.

    2001-10-02

    Accumulations of two solid phases have formed scale deposits in the Savannah River Site 2H Evaporator system since late 1996. The aluminosilicate scale deposits caused the evaporator pot to become inoperable in October 1999. Accumulations of the diuranate phase have caused criticality concerns in the SRS 2H Evaporator. In order to ensure that similar deposits are not and will not form in the SRS 3H Evaporator, thermodynamically derived activity diagrams specific to the feeds processed from Tanks 30 and 32 are evaluated in this report.

  8. Symmetry constraint for foreground extraction.

    PubMed

    Fu, Huazhu; Cao, Xiaochun; Tu, Zhuowen; Lin, Dongdai

    2014-05-01

    Symmetry as an intrinsic shape property is often observed in natural objects. In this paper, we discuss how explicitly taking into account the symmetry constraint can enhance the quality of foreground object extraction. In our method, a symmetry foreground map is used to represent the symmetry structure of the image, which includes the symmetry matching magnitude and the foreground location prior. Then, the symmetry constraint model is built by introducing this symmetry structure into the graph-based segmentation function. Finally, the segmentation result is obtained via graph cuts. Our method encourages objects with symmetric parts to be consistently extracted. Moreover, our symmetry constraint model is applicable to weak symmetric objects under the part-based framework. Quantitative and qualitative experimental results on benchmark datasets demonstrate the advantages of our approach in extracting the foreground. Our method also shows improved results in segmenting objects with weak, complex symmetry properties.

  9. The molecular structure and vibrational spectrum of the cyclopropenyl cation, C3H + 3, and its deuterated isotopomers

    NASA Astrophysics Data System (ADS)

    Lee, Timothy J.; Willetts, Andrew; Gaw, Jeffrey F.; Handy, Nicholas C.

    1989-04-01

    The equilibrium structure, harmonic vibrational frequencies, infrared intensities, anharmonic constants, vibration-rotation interaction constants and quartic and sextic centrifugal distortion constants of C3H+3, the cyclopropenyl cation, and its deuterated isotopomers have been determined via purely ab initio quantum-mechanical methods. Two one-particle basis sets have been employed in conjunction with second-order M≂ller-Plesset perturbation theory (MP2), singles and doubles configuration interaction (CISD), and singles and doubles coupled cluster (CCSD). The best estimate of the harmonic frequencies is obtained from MP2 with a triple zeta plus double polarization (TZ2P) basis set. The anharmonic analysis has been determined via second-order perturbation theory using a double zeta plus polarization (DZP) self-consistent-field (SCF) full quartic force field. A generalization of formulas for the anharmonic analysis of D3h symmetric tops is discussed. The complete quartic force field in symmetry internal coordinates is given. Additionally, the anharmonic constants, vibration-rotation interaction constants and quartic and sextic centrifugal distortion constants for C3H+3 and C3D+3 are reported. Predictions of the fundamental vibrational frequencies for C3H+3 and all its deuterated isotopomers are reported. At the TZ2P MP2 level of theory the equilibrium structure of cyclopropenyl cation is Re(C-C)=1.3647 Å, Re(C-H)=1.0753 Å. Coupling the TZ2P MP2 harmonic frequencies with the DZP SCF anharmonic corrections, the infrared active fundamentals of C3H+3 are predicted to occur at 3136, 1289, 939, and 773 cm-1, with those of C3D+3 predicted to occur at 2346, 1243, 684, and 567 cm-1.

  10. Structural basis for recognition of H3K56-acetylated histone H3-H4 by the chaperone Rtt106

    SciTech Connect

    Su, Dan; Hu, Qi; Li, Qing; Thompson, James R; Cui, Gaofeng; Fazly, Ahmed; Davies, Brian A; Botuyan, Maria Victoria; Zhang, Zhiguo; Mer, Georges

    2013-04-08

    Dynamic variations in the structure of chromatin influence virtually all DNA-related processes in eukaryotes and are controlled in part by post-translational modifications of histones. One such modification, the acetylation of lysine 56 (H3K56ac) in the amino-terminal α-helix (αN) of histone H3, has been implicated in the regulation of nucleosome assembly during DNA replication and repair, and nucleosome disassembly during gene transcription. In Saccharomyces cerevisiae, the histone chaperone Rtt106 contributes to the deposition of newly synthesized H3K56ac-carrying H3-H4 complex on replicating DNA, but it is unclear how Rtt106 binds H3-H4 and specifically recognizes H3K56ac as there is no apparent acetylated lysine reader domain in Rtt106. Here, we show that two domains of Rtt106 are involved in a combinatorial recognition of H3-H4. An N-terminal domain homodimerizes and interacts with H3-H4 independently of acetylation while a double pleckstrin-homology (PH) domain binds the K56-containing region of H3. Affinity is markedly enhanced upon acetylation of K56, an effect that is probably due to increased conformational entropy of the αN helix of H3. Our data support a mode of interaction where the N-terminal homodimeric domain of Rtt106 intercalates between the two H3-H4 components of the (H3-H4)2 tetramer while two double PH domains in the Rtt106 dimer interact with each of the two H3K56ac sites in (H3-H4)2. We show that the Rtt106-(H3-H4)2 interaction is important for gene silencing and the DNA damage response.

  11. /sup 3/H-PAF-acether displacement and inhibition of binding in intact human platelets by BN 52021

    SciTech Connect

    Korth, R.; Le Couedic, J.P.; Benveniste, J.

    1986-03-05

    Intact washed human platelets incubated at 20/sup 0/C in Tyrode's buffer containing 0.25% (w/v) bovine serum albumin bound /sup 3/H paf-acether in a concentration (0-6.5 nM) and time (0-60 min) dependent manner (n=3). BN 52021 (60 ..mu..M) a chemically defined extract from Ginkgo biloba inhibited the binding of increasing concentrations of /sup 3/H paf-acether. Calculated differences between /sup 3/H paf-acether binding in the presence or absence of BN 52021 (60 ..mu..M) reached nearly a plateau in concentrations higher than 0.65 nM /sup 3/H paf-acether. Increasing concentrations of BN 52021 (0-60 ..mu..M) as well as of unlabelled paf-acether (0-50 nM) prevented within 15 min /sup 3/H paf-acether binding (0.65 nM) to platelets in a concentration-dependent way. Increasing BN 52021 concentrations (0-60 ..mu..M) also displaced platelet-bound /sup 3/H paf-acether (0.65 nM) in a concentration-dependent way. Displacement increased with the time length of platelet incubation with BN 52021 and reached a plateau at 15 min. Platelet-bound /sup 3/H paf-acether displacement of 28.3 +/- 6.3%, 31.1 +/- 4.0% and 26.7 +/- 5.6% was observed using 50 nM unlabelled paf-acether, 60 ..mu..M BN 52021 or both substances together (vs 4.3 +/- 7.2% for vehicle alone). No degradation of /sup 3/H paf-acether occurred as assessed by high pressure liquid chromatography. These results demonstrate that BN 52021 competes directly with paf-acether binding sites on human platelets.

  12. Effective theory of 3H and 3He

    NASA Astrophysics Data System (ADS)

    König, Sebastian; Grießhammer, Harald W.; Hammer, H.-W.; van Kolck, U.

    2016-06-01

    We present a new perturbative expansion for pionless effective field theory with Coulomb interactions in which at leading order (LO) the spin-singlet nucleon-nucleon channels are taken in the unitarity limit. Presenting results up to next-to-leading order for the Phillips line and the neutron-deuteron doublet-channel phase shift, we find that a perturbative expansion in the inverse {}1{S}0 scattering lengths converges rapidly. Using a new systematic treatment of the proton-proton sector that isolates the divergence due to one-photon exchange, we renormalize the corresponding contribution to the {}3{{H}} -{}3{He} binding energy splitting and demonstrate that the Coulomb force in pionless EFT is a completely perturbative effect in the trinucleon bound-state regime. In our new expansion, the LO is exactly isospin-symmetric. At next-to-leading order, we include isospin breaking via the Coulomb force and two-body scattering lengths, and find for the energy splitting {({E}B{(}3{He})-{E}B{(}3{{H}}))}{NLO}\\quad =(-0.86+/- 0.17)\\quad {MeV}.

  13. Toxicokinetics of ( sup 3 H)microcystin-LR in mice

    SciTech Connect

    Robinson, N.A.; Matson, C.F.; Miura, G.A.; Lynch, T.G.; Pace, J.G. )

    1990-02-26

    Toxicokinetics of ({sup 3}H)microcystin-LR, an algal hepatotoxin, was measured in CD-1 mice (iv, 35 {mu}g/kg, sublethal). The distribution and biological half-lives in plasma were 0.8 and 7 minutes, respectively. Liver rapidly accumulated toxin; uptake half-life was 7 minutes. After 60 minutes, liver, kidney, intestine and carcass retained 67{+-}4, 0.8{+-}0.1, 8.6{+-}0.7 and 6{+-}2% of dose, respectively. By 8 days, 18{+-}1 and 7.6{+-}0.6% of the administered radiolabel appeared in feces and urine, while liver and carcass retained 50{+-}2 and 8{+-}3%, respectively. In urine (6 and 12 hours) and feces (6, 12 and 24 hours) {approximately}60% of the tritium was associated with the parent compound. Hepatic radiolabel was tightly bound to cytosolic protein(s). One hour after injection, 27{+-}3% of the hepatic radiolabel was parent compound and 73{+-}3% was a more-polar component (peak 1). By 8 days, there was a redistribution of hepatic radioactivity: 69{+-}2% with a parent and 4{+-}0.5% with peak 1. The authors conclude that ({sup 3}H)MCYST rapidly accumulated in liver, was metabolized and was associated with cytosolic protein.

  14. Tissue distribution of 3H-terbutaline in rabbits.

    PubMed

    Hsu, C H; Robinson, C P; Basmadjian, G P

    1994-01-01

    Terbutaline is a widely used, selective beta 2-adrenergic agonist whose penetration into brain has not been demonstrated in laboratory animals. Although its tissue uptake has been reported in some animals, no uptake into brain has been demonstrated. A single dose of 20 microCi of 3H-terbutaline along with 10 mg/kg of unlabeled terbutaline was injected into a rabbit marginal ear vein. The distribution of 3H-terbutaline in several tissues was determined 0.5, 1, 3, or 6 hr later. Radioactivity in the brain was well-maintained over the 6 hr observation period. In most tissues, radioactivity peaked in less than 1 hr, then declined. Radioactivity in the urine was high at all time periods and was highest at 3 hr. Thus, terbutaline or a metabolite(s) does cross the blood-brain barrier in rabbits, and the radioactivity in the rabbit brain does not decrease during the 6 hours following terbutaline injection.

  15. A Search for Interstellar Oxiranecarbonitrile (C3H3NO)

    NASA Technical Reports Server (NTRS)

    Dicken, J. E.; Irvine, W. M.; Ohishi, M.; Arrhenius, G.; Bauder, A.; Mueller, F.; Eschenmoser, A.

    1996-01-01

    We report a search in cold, quiescent and in 'hot core' type interstellar molecular clouds for the small cyclic molecule oxiranecarbonitrile (C3H3NO), which has been suggested as a precursor of important prebiotic molecules. We have determined upper limits to the column density and fractional abundance for the observed sources and find that, typically, the fractional abundance by number relative to molecular hydrogen Of C3H3NO is less than a few times 10(exp -10). This limit is one to two orders of magnitude less than the measured abundance of such similarly complex species as CH3CH2CN and HCOOCH3 in well-studied hot cores. A number of astrochemical discoveries were made, including the first detection of the species CH3CH2CN in the massive star-forming clouds G34.3+0.2 and W51M and the first astronomical detections of some eight rotational transitions of CH3CH2CN, CH3CCH, and HCOOCH3. In addition, we found 8 emission lines in the 89 GHz region and 18 in the 102 GHz region which we were unable to assign.

  16. The 3H-3He Charge Radii Difference

    SciTech Connect

    Myers, Luke S.; Arrington, John R.; Higinbotham, Douglas W.

    2016-03-01

    The upcoming E12-14-009 [1] experiment at Jefferson Lab will determine the ratio of the electric form factors for the A=3 mirror nuclei 3He and 3H. The measurement will use a 1.1 GeV electron beam, a special collimator plate to allow for simultaneous optics measurements, and the low-activity tritium target being prepared for Jefferson Lab. By observing the dependence of the form factor ratio as a function of Q2 over 0.05–0.09 GeV2, the dependence of the radii extraction on the shape of the form factors is minimized. As a result, we anticipate the uncertainty of the extracted charge radii difference to be 0.03 fm, a reduction of 70% from the current measurement. Using precise measurements of the 3He charge radius from isotopic shift or μHe measurements [2–4], we can deduce the absolute 3H charge radius. The results will provide a direct comparison to recent calculations of the charge radii.

  17. Beryllium-induced immune response in C3H mice

    SciTech Connect

    Benson, J.M.; Bice, D.E.; Nikula, K.J.

    1995-12-01

    Studies conducted at ITRI over the past several years have investigated whether Beagle dogs, monkeys, and mice are suitable models for human chronic beryllium-induced lung disease (CBD). Recent studies have focused on the histopathological and immunopathological changes occurring in A/J and C3H/HeJ mice acutely exposed by inhalation to Be metal. Lung lesions in both strains of mice included focal lymphocyte aggregates comprised primarily of B lymphocytes and lesser amounts of T-helper lymphocytes and microgranulomas consisting chiefly of macrophages and T-helper lymphocytes. The distribution of proliferating cells within the microgranulomas was similar to the distribution of T-helper cells. These results strongly suggested that A/J and C3H/HeJ mice responded to inhaled Be metal in a fashion similar to humans in terms of pulmonary lesions and the apparent in situ proliferation of T-helper cells. Results of these studies confirm lymphocyte involvement in the pulmonary response to inhaled Be metal.

  18. Human myometrial adrenergic receptors during pregnancy: identification of the alpha-adrenergic receptor by (/sup 3/H) dihydroergocryptine binding

    SciTech Connect

    Jacobs, M.M.; Hayashida, D.; Roberts, J.M.

    1985-07-15

    The radioactive alpha-adrenergic antagonist (/sup 3/H) dihydroergocryptine binds to particulate preparations of term pregnant human myometrium in a manner compatible with binding to the alpha-adrenergic receptor (alpha-receptor). (/sup 3/H) Dihydroergocryptine binds with high affinity (KD = 2 nmol/L and low capacity (receptor concentration = 100 fmol/mg of protein). Adrenergic agonists compete for (/sup 3/H) dihydroergocryptine binding sites stereo-selectively ((-)-norepinephrine is 100 times as potent as (+)-norepinephrine) and in a manner compatible with alpha-adrenergic potencies (epinephrine approximately equal to norepinephrine much greater than isoproterenol). Studies in which prazosin, an alpha 1-antagonist, and yohimbine, and alpha 2-antagonist, competed for (/sup 3/H) dihydroergocryptine binding sites in human myometrium indicated that approximately 70% are alpha 2-receptors and that 30% are alpha 1-receptors. (/sup 3/H) dihydroergocryptine binding to human myometrial membrane particulate provides an important tool with which to study the molecular mechanisms of uterine alpha-adrenergic response.

  19. Chronic ethanol administration increases the binding of sup 3 H Ro-15-4513 in primary cultured spinal cord neurons

    SciTech Connect

    Mlatre, M.; Ticku, M.K. )

    1989-02-09

    Ro 15-4513 (ethyl-8-azido-5, 6-dihydro-5-methyl-6-oxo-4H-imidazo (1,5{alpha}), (1,4) benzodiazepine-3-carboxylate) is reported to be a selective ethanol antagonist in biochemical and behavioral studies. The effect of chronic ethanol treatment on the binding of ({sup 3}H)Ro 15-4513 was investigated in cultured spinal cord neurons, which are shown to possess all the elements of GABA benzodiazepine receptor complex. Chronic ethanol treatment (50 mM for 6 hr, 12 hr, 18 hr, 3 days, and 5{sub 3} days) produced an increase in the specific binding of ({sub 3}H)Ro 15-4513. The increase in binding in these neurons was due to an increase in the number (B{sub max}) of receptor sites. This effect was specific for Ro 15-4513, since identical ethanol treatment did not alter the binding of benzodiazepine antagonist ({sup 3}H)Ro 15-1788 or agonist ({sup 3}H)flunitrazepam or inverse agonist ({sup 3}H)methyl-{beta}-carboline-3-carboxylate. Similar results have been reported following chronic ethanol treatment to rats. These results suggest that the Ro 15-4513 binding sites on the oligomeric GABA receptor complex are altered following chronic ethanol administration, and support the notion of a unique role of Ro 15-4513 as an ethanol antagonist.

  20. Characterization of (/sup 3/H)nifedipine binding to intact vascular smooth muscle cells

    SciTech Connect

    Sumimoto, K.; Hirata, M.; Kuriyama, H.

    1988-01-01

    Specific binding of the dihydropyridine Ca2+ antagonist (/sup 3/H)nifedipine to dispersed smooth muscle cells of the porcine coronary artery was investigated and the findings were compared with the binding to microsomes of smooth muscles. Specific binding to intact cells was saturable and reversible. The dissociation constant was 1.93 +/- 0.42 nM and the maximal binding capacity was 59.6 +/- 12.4 fmol/10(6) cells, as assessed by Scatchard analysis of the equilibrium binding at 25 degrees C. The Kd value with intact cells was slightly higher than that observed with microsomes. Specific binding of (/sup 3/H)nifedipine to intact cells was completely displaced by unlabeled dihydropyridine derivatives. Among other Ca2+ antagonists, verapamil and d-cis-diltiazem partially and flunarizine completely inhibited the binding. In the case of microsomes, d-cis-diltiazem stimulated the binding of (/sup 3/H)nifedipine. These results suggest that there may be multiple binding sites for different subclasses of Ca2+ antagonists. Polyvalent cations had no effect on the binding to intact cells. In the case of ethylene glycol-bis(beta-aminoethyl ether)-N,N,N',N'-tetraacetic acid (EGTA)-treated microsomes, the addition of CaCl/sub 2/ and BaCl/sub 2/ increased the Bmax, but the Kd value remained unchanged. MnCl/sub 2/ and CdCl/sub 2/ had stimulatory or inhibitory effects, depending on the concentrations, whereas LaCl3 had no effect. The effect of membrane depolarization on the binding was also examined. When the intact cells were incubated in high (K+)o solution for 60 min, the Kd was lowered to 1.4 nM from the control value of 2.0 nM, thereby indicating that (/sup 3/H)nifedipine binds to Ca2+ channels, with a higher affinity, at depolarized states.

  1. Symmetry in Season.

    ERIC Educational Resources Information Center

    Seidel, Judith Day

    1998-01-01

    Presents activities that demonstrate how technology can help students discover the mathematics in nature. Claims that these experiences can clarify students' vision of the symmetry of beauty that fills the world beyond the computer. Concludes that the use of flexible software tools helps students explore how a shape is affected when they change…

  2. Horror Vacui Symmetry.

    ERIC Educational Resources Information Center

    Crumpecker, Cheryl

    2003-01-01

    Describes an art lesson used with children in the third grade to help them learn about symmetry, as well as encouraging them to draw larger than usual. Explains that students learn about the belief called "Horror Vacui" of the Northwest American Indian tribes and create their interpretation of this belief. (CMK)

  3. Bindings of /sup 3/H-prazosin and /sup 3/H-yohimbine to alpha adrenoceptors in the guinea-pig stomach

    SciTech Connect

    Taniguchi, T.; Nishikawa, H.

    1988-01-01

    Alpha adrenoceptor subtypes have been investigated by radioligand binding study in guinea-pig stomach using /sup 3/H-prazosin and /sup 3/H-yohimbine. The specific /sup 3/H-prazosin binding to guinea-pig stomach was saturable and of high affinity with a Bmax of 33 fmol/mg protein. Specific /sup 3/H-yohimbine binding to the tissue was also saturable and of high affinity with a Bmax of 150 fmol/mg protein. Adrenergic drugs competed for /sup 3/H-prazosin binding in order of prazosin > phentolamine > methoxamine > norepinephrine > clonidine > epinephrine > yohimbine. These drugs competed for /sup 3/H-yohimbine binding in order of yohimbine > phentolamine > clonidine > epinephrine > norepinephrine > prazosin > methoxamine. They also examined whether dopamine receptors exist in guinea-pig stomach, using radioligand binding study. Specific binding of /sup 3/H-spiperone, /sup 3/H-apomorphine, /sup 3/H-dopamine and /sup 3/H-domperidone was not detectable in the stomach. Dopaminergic drugs such as dopamine, haloperidol, domperidone and sulpiride competed for /sup 3/H-prazosin binding in order of haloperidol > domperidone > dopamine > sulpiride. Metoclopramide, sulpiride and dopamine competed for /sup 3/H-yohimbine binding in order of metoclopramide > sulpiride > dopamine.

  4. Infrared Predissociation Spectroscopy of the Hydrocarbon Cations C_3H^+, C_2H^+, and C_3H_2^+

    NASA Astrophysics Data System (ADS)

    Brünken, Sandra; Lipparini, Filippo; Gauss, Jürgen; Stoffels, Alexander; Redlich, Britta; van der Meer, Lex; Berden, Giel; Oomens, Jos; Schlemmer, Stephan

    2016-06-01

    Reactive hydrocarbon cations play an important role in the astrochemistry of the interstellar medium, but spectroscopic data, needed for their identification in astronomical observations, is sparse. Here we report the first gas-phase vibrational spectra of the linear C_3H^+ (^1 Σ), the radical cation C_2H^+ (^3 Π), and the linear-/cyclic-C_3H_2^+ (^2 Π /^2A_1, resp.). Broadband spectra were recorded by Ne- and He-messenger infrared-predissociation (IR-PD) action spectroscopy in a cryogenic (4-11 K) ion trap instrument (FELion) in the 250-3500 {wn} range using a free electron laser and a MIR-OPO at the FELIX (Free-Electron Laser for Infrared eXperiments) laboratory. The band positions (determined with a precision of 1-2 wn) covering the C-H and C-C stretching as well as several bending modes are compared to high-level (CCSD(T) with large basis sets) quantum-chemical calculations with an emphasis on anharmonic effects and on the influence of the rare-gas messenger atom. The experimental and theoretical data provide a solid basis for subsequent IR high-resolution studies, with the ultimate goal to predict and measure accurate rotational spectra for a radio-astronomical search of these molecular ions in space.

  5. The tissue-specific distribution of 3H-seocalcitol (EB 1089) and 3H-calcitriol in rats.

    PubMed

    Kissmeyer, Anne-Marie; Nielsen, Jeanet Løgsted; Binderup, Lise

    2004-05-01

    Seocalcitol (EB 1089) is under development for the treatment of hepato-cellular carcinoma (HCC). The tissue distribution of 3H-seocalcitol was investigated in comparison to 3H-calcitriol in rats. Quantitative whole-body autoradiography was used to quantify the tissue distribution. The greatest difference in distribution between the two compounds was observed in the bloodstream. For most tissues the ratio seocalcitol/calcitriol varied between 0.2 and 3.1. The concentration of radioactivity in the liver was almost the same for the two compounds. For seocalcitol the concentration in the liver was 10 times higher than in serum. Assuming that the liver/serum concentration ratio is the same in rats and humans, the concentration of seocalcitol in the human liver is expected to be higher than the concentration resulting in more than 50% inhibition of cancer cell proliferation, and thus pharmacologically effective in HCC. It is questionable whether calcitriol would be present in the human liver in sufficient concentrations to be effective for the treatment of HCC, as the antiproliferative activity of calcitriol is generally more than 10-fold lower compared to that of seocalcitol and as calcitriol can only be administered at a dose that is ca. three-fold lower than the dose of seocalcitol.

  6. One dimensional 1H, 2H and 3H

    NASA Astrophysics Data System (ADS)

    Vidal, A. J.; Astrakharchik, G. E.; Vranješ Markić, L.; Boronat, J.

    2016-05-01

    The ground-state properties of one-dimensional electron-spin-polarized hydrogen 1H, deuterium 2H, and tritium 3H are obtained by means of quantum Monte Carlo methods. The equations of state of the three isotopes are calculated for a wide range of linear densities. The pair correlation function and the static structure factor are obtained and interpreted within the framework of the Luttinger liquid theory. We report the density dependence of the Luttinger parameter and use it to identify different physical regimes: Bogoliubov Bose gas, super-Tonks-Girardeau gas, and quasi-crystal regimes for bosons; repulsive, attractive Fermi gas, and quasi-crystal regimes for fermions. We find that the tritium isotope is the one with the richest behavior. Our results show unambiguously the relevant role of the isotope mass in the properties of this quantum system.

  7. Inhibition of (/sup 3/H)nitrendipine binding by phospholipase A/sub 2/

    SciTech Connect

    Goldman, M.E.; Pisano, J.J.

    1985-10-07

    Phospholipase A/sub 2/ from several sources inhibited (/sup 3/H)nitrendipine binding to membranes from brain, heart and ileal longitudinal muscle. The enzymes from bee venom and Russell's viper venom were most potent, having IC/sub 50/ values of approximately 5 and 14 ng/ml, respectively, in all three membrane preparations. Inhibition of binding by bee venom phospholipase A/sub 2/ was time- and dose-dependent. Mastoparan, a known facilitator of phospholipase A/sub 2/ enzymatic activity, shifted the bee venom phospholipase A/sub 2/ dose-response curve to the left. Pretreatment of brain membranes with bee venom phospholipase A/sub 2/ (10 ng/ml) for 15 min caused a 2-fold increase in the K/sub d/ without changing the B/sub max/ compared with untreated membranes. Extension of the preincubation period to 30 min caused no further increase in the K/sub d/ but significantly decreased the B/sub max/ to 71% the value for untreated membranes. (/sup 3/H)Nitrendipine, preincubated with bee venom phospholipase A/sub 2/, was recovered and found to be fully active, indicating that the phospholipase A/sub 2/ did not modify the ligand. It is concluded that phospholipase A/sub 2/ acts on the membrane at or near the (/sup 3/H)nitrendipine binding site and that phospholipids play a key role in the interactions of 1,4 dihydropyridine calcium channel antagonists with the dihydropyridine binding site. 33 references, 3 figures, 1 table.

  8. The binding of (3H)AF-DX 384 to rat ileal smooth muscle muscarinic receptors

    SciTech Connect

    Entzeroth, M.; Mayer, N. )

    1991-01-01

    The tritiated cardioselective muscarinic antagonist AF-DX 384 (5,11-dihydro-11-(2-(-(8-dipropylamino)methyl)-1-piperidinyl-ethyl-amino-carbonyl)-6H-pyrido (2,3-b) (1,4)benzodiazepin-6-one) was used to label muscarinic receptors in the rat ileum. Saturation binding to membrane suspensions revealed a high affinity binding site with a Kd of 9.2 nM. The maximal number of binding sites labeled in this tissue (Bmax) is 237 fmol/mg protein. The association and dissociation kinetics were well represented by single exponential reactions, and the dissociation constant obtained from the ratio of rate constants was in agreement with that derived from saturation experiments. Specific binding was inhibited by muscarinic antagonists with a rank order of potencies of atropine (pKi: 8.80) greater than 4-DAMP (pKi: 8.23) = AF-DX 384 (pKi: 8.20) greater than AF-DX 116 (pKi: 7.09) = hexahydro-sila-difenidol (pKi: 6.97) greater than pirenzepine (pKi: 6.49) and is consistent with the interaction of (3H)AF-DX 384 with muscarinic receptors of the M2 subtype. It can be concluded that (3H)AF-DX 384 can be used to selectively label M2 muscarinic receptors in heterogeneous receptor populations.

  9. Asymmetry of /sup 3/H- imipramine binding may predict psychiatric illness

    SciTech Connect

    Demeter, E.; Tekes, K.; Majorossy, K.; Palkovits, M.; Soos, M.; Magyar, K.; Somogyl, E.

    1989-01-01

    The B/sub max/ and Kd values for /sup 3/H-imipramine binding were measured in post-mortem human brains from drug-free selected psychiatric subject homicide victims and normal controls. The two groups were comparable in age and gender. The number of imipramine binding sites in the frontal cortices of psychiatric subjects had significantly higher B/sub max/ values in the left hemisphere than in the right hemisphere. Inversely, the number of imipramine binding sites in the frontal cortices of normal controls were significantly higher in the right brain than in the left brain. It was postulated that the inhibiting effect of central serotonin has weakened in psychiatric cases, therefore the changes of presynaptic serotonergic activity might be associated with psychiatric illness in the left hemisphere of human brain.

  10. Autoradiographic localization of adenosine receptors in rat brain using (/sup 3/H)cyclohexyladenosine

    SciTech Connect

    Goodman, R.R.; Synder, S.H.

    1982-09-01

    Adenosine (A1) receptor binding sites have been localized in rat brain by an in vitro light microscopic autoradiographic method. The binding of (/sup 3/H)N6-cyclohexyladenosine to slide-mounted rat brain tissue sections has the characteristics of A1 receptors. It is saturable with high affinity and has appropriate pharmacology and stereospecificity. The highest densities of adenosine receptors occur in the molecular layer of the cerebellum, the molecular and polymorphic layers of the hippocampus and dentate gyrus, the medial geniculate body, certain thalamic nuclei, and the lateral septum. High densities also are observed in certain layers of the cerebral cortex, the piriform cortex, the caudate-putamen, the nucleus accumbens, and the granule cell layer of the cerebellum. Most white matter areas, as well as certain gray matter areas, such as the hypothalamus, have negligible receptor concentrations. These localizations suggest possible central nervous system sites of action of adenosine.

  11. Ascorbic acid and striatal transport of (/sup 3/H)1-methyl-4-phenylpyridine (MPP/sup +/) and (/sup 3/H)dopamine

    SciTech Connect

    Debler, E.A.; Hashim, A.; Lajtha, A.; Sershen, H.

    1988-01-01

    The inhibition of uptake of (/sup 3/H)dopamine and (/sup 3/H)1-methyl-4-phenylpyridine (MPP/sup +/) was examined in mouse striatal synaptosomal preparations. Kinetic analysis indicated that ascorbic acid is a noncompetitive inhibitor of (/sup 3/H)MPP/sup +/ uptake. No inhibition of (/sup 3/H)dopamine uptake is observed. The dopamine uptake blockers, GBR-12909, cocaine, and mazindol strongly inhibit (IC/sub 50/ < 1 ..mu..M) both (/sup 3/H)dopamine and (/sup 3/H)MPP/sup +/ transport. Nicotine, its metabolites, and other tobacco alkaloids are weak inhibitors except 4-phenylpyridine and lobeline, which are moderate inhibitors of both (/sup 3/H)dopamine and (/sup 3/H)MPP/sup +/ uptake. These similarities in potencies are in agreement with the suggestion that (/sup 3/H)MPP/sup +/ and (/sup 3/H) are transported by the same carrier. The differences observed in the alteration of dopaminergic transport and mazindol binding by ascorbic acid suggest that ascorbic acid's effects on (/sup 3/H)MPP/sup +/ transport are related to translocation and/or dissociation processes occurring subsequent to the initial binding event.

  12. Dynamical Symmetries in Classical Mechanics

    ERIC Educational Resources Information Center

    Boozer, A. D.

    2012-01-01

    We show how symmetries of a classical dynamical system can be described in terms of operators that act on the state space for the system. We illustrate our results by considering a number of possible symmetries that a classical dynamical system might have, and for each symmetry we give examples of dynamical systems that do and do not possess that…

  13. Reflections on Symmetry and Proof

    ERIC Educational Resources Information Center

    Merrotsy, Peter

    2008-01-01

    The concept of symmetry is fundamental to mathematics. Arguments and proofs based on symmetry are often aesthetically pleasing because they are subtle and succinct and non-standard. This article uses notions of symmetry to approach the solutions to a broad range of mathematical problems. It responds to Krutetskii's criteria for mathematical…

  14. Specific 3H-haloperidol binding to dopamine receptors in the anterior byssus retractor muscle of Mytilus edulis.

    PubMed

    Ishii, Y; Takayanagi, I

    1982-12-01

    The anterior byssus retractor muscle (ABRM) of Mytilus edulis has specific dopamine receptors. We carried out a radioligand binding assay for dopamine receptors in ABRM using (3H)-haloperidol as the radioligand. High affinity binding of (3H)-haloperidol has been shown. Scatchard analysis showed a single component of binding with an apparent equilibrium constant (KD) of 1.6 nM and a maximal number of binding sites (Bmax) of 219 fmoles/mg protein. Some dopamine antagonists displaced 3 nM (3H)-haloperidol binding, and the IC50 and Ki-value of these drugs were calculated. Considering these results, this muscle is thought to be suitable for a study of the dopamine receptors.

  15. Selective destruction of nigrostriatal dopaminergic neurons does not alter [3H]-ryanodine binding in rat striatum.

    PubMed

    Noël, F; Geurts, M; Maloteaux, J M

    2000-02-01

    Dopamine nigrostriatal neurons are important for motor control and may contain a particularly dense population of ryanodine receptors involved in the control of dopamine release. To test this hypothesis, we used a classical model of unilateral selective lesion of these neurons in rats based on 6-hydroxydopamine (6-OHDA) injection into the substantia nigra. Binding of [3H]-GBR 12935, used as a presynaptic marker since it labels specifically the dopamine uptake complex, was dramatically decreased by 83-100% in striatum homogenates after 6-OHDA lesion. On the contrary, no reduction of [3H]-ryanodine binding was observed. The present data indicate that [3H]-ryanodine binding sites present in rat striatum are not preferentially localized in dopaminergic terminals.

  16. PSEUDOSPIN SYMMETRY IN NUCLEI, SPIN SYMMETRY IN HADRONS

    SciTech Connect

    P. PAGE; T. GOLDMAN; J. GINOCCHIO

    2000-08-01

    Ginocchio argued that chiral symmetry breaking in QCD is responsible for the relativistic pseudospin symmetry in the Dirac equation, explaining the observed approximate pseudospin symmetry in sizable nuclei. On a much smaller scale, it is known that spin-orbit splittings in hadrons are small. Specifically, new experimental data from CLEO indicate small splittings in D-mesons. For heavy-light mesons we identify a cousin of pseudospin symmetry that suppresses these splittings in the Dirac equation, known as spin symmetry. We suggest an experimental test of the implications of spin symmetry for wave functions in electron-positron annihilation. We investigate how QCD can give rise to two different dynamical symmetries on nuclear and hadronic scales.

  17. Receptors for /sup 3/H-octopamine in the adult firefly light organ

    SciTech Connect

    Hashemzadeh, H.; Hollingworth, R.M.; Voliva, A.

    1985-08-05

    /sup 3/H-Octopamine binds reversibly and with high affinity to sites on adult firefly light organ membranes. The binding is characterized by multiple affinities. Scatchard analysis supported a two site binding model with a tentative Kd value of about 1 nM for the high affinity component. The more abundant lower affinity site had a Kd value of about 60 nM. Guanyl nucleotides (Gpp(NH)p and GTP) greatly reduced the apparent number of octopamine binding sites. Competition studies with known octopaminergic agonists including the formamidine pesticides chlordimeform (CDM) and N-demethylchlordimeform (DCDM) showed the following rank order of potencies in displacing octopamine: DCDM > octopamine = synephrine > naphazoline > clonidine > CDM. It was also observed that phentolamine was much more active than propranolol in antagonizing OA-binding. These relative activities are similar to the abilities of the same compounds to alter adenylate cyclase activity in light organ homogenates. Together with the effect of GTP on binding, these results suggest that the binding sites are functional octopamine receptors of the light organ. 27 references, 3 figures, 1 table.

  18. Assessing the use of 3H-3He dating to determine the subsurface transit time of cave drip waters.

    PubMed

    Kluge, Tobias; Wieser, Martin; Aeschbach-Hertig, Werner

    2010-09-01

    (3)H-(3)He measurements constitute a well-established method for the determination of the residence time of young groundwater. However, this method has rarely been applied to karstified aquifers and in particular to drip water in caves, despite the importance of the information which may be obtained. Besides the determination of transfer times of climate signals from the atmosphere through the epikarst to speleothems as climate archives, (3)H-(3)He together with Ne, Ar, Kr, Xe data may also help to give new insights into the local hydrogeology, e.g. the possible existence of a perched aquifer above a cave. In order to check the applicability of (3)H-(3)He dating to cave drips, we collected drip water samples from three adjacent caves in northwestern Germany during several campaigns. The noble gas data were evaluated by inverse modelling to obtain recharge temperature and excess air, supporting the calculation of the tritiogenic (3)He and hence the (3)H-(3)He age. Although atmospheric noble gases were often found to be close to equilibrium with the cave atmosphere, several drip water samples yielded an elevated (3)He/(4)He ratio, providing evidence for the accumulation of (3)He from the decay of (3)H. No significant contribution of radiogenic (4)He was found, corresponding to the low residence times mostly in the range of one to three years. Despite complications during sampling, conditions of a perched aquifer could be confirmed by replicate samples at one drip site. Here, the excess air indicator ΔNe was about 10 %, comparable to typical values found in aquifers in mid-latitudes. The mean (3)H-(3)He age of 2.1 years at this site presumably refers to the residence time in the perched aquifer and is lower than the entire transit time of 3.4 years estimated from the tritium data.

  19. Local Rotational Symmetries.

    DTIC Science & Technology

    1985-08-01

    spanner wrench and the teaspoon, the pointed jaws of the wrench, and the main axes of the gourd , the pear, the squash, and the bowl of the teaspoon...regions such as the handle of the spanner wrench and the main axes of the gourd , squash, and teaspoon, and also pointed regions such as the end of the...Local Symmetry representation does not provide in- tuitively acceptable analyses for round regions, such as the lemon and the round ends of the gourd

  20. Binary-Symmetry Detection

    NASA Technical Reports Server (NTRS)

    Lopez, Hiram

    1987-01-01

    Transmission errors for zeros and ones tabulated separately. Binary-symmetry detector employs psuedo-random data pattern used as test message coming through channel. Message then modulo-2 added to locally generated and synchronized version of test data pattern in same manner found in manufactured test sets of today. Binary symmetrical channel shows nearly 50-percent ones to 50-percent zeroes correspondence. Degree of asymmetry represents imbalances due to either modulation, transmission, or demodulation processes of system when perturbed by noise.

  1. Chiral symmetry and pentaquarks

    SciTech Connect

    Dmitri Diakonov

    2004-07-01

    Spontaneous chiral symmetry breaking, mesons and baryons are illustrated in the language of the Dirac theory. Various forces acting between quarks inside baryons are discussed. I explain why the naive quark models typically overestimate pentaquark masses by some 500 MeV and why in the fully relativistic approach to baryons pentaquarks turn out to be light. I discuss briefly why it can be easier to produce pentaquarks at low than at high energies.

  2. Spermidine reverses arcaine's inhibition of N-methyl-D-aspartate-induced hippocampal ( sup 3 H)norepinephrine release

    SciTech Connect

    Sacaan, A.I.; Johnson, K.M. )

    1990-12-01

    The inhibition of N-methyl-D-aspartate (NMDA)-induced ({sup 3}H)norepinephrine (({sup 3}H)NE) release by a putrescine analog was studied. We report that arcaine, diguanidinobutane, a putative competitive polyamine antagonist, completely and noncompetitively antagonized NMDA-induced ({sup 3}H)NE release from rat hippocampal minces with an IC50 value of 102 microM. Arcaine did not alter kainate- or potassium-induced ({sup 3}H)NE release suggesting a specific effect on NMDA-mediated responses. Spermidine did not alter NMDA-induced ({sup 3}H)NE release, nor did it reverse the effect of arcaine when introduced in a normal physiologic superfusion buffer. However, spermidine reversed the effect of arcaine when superfusing with buffer that contained 5% (v/v) of the organic solvent dimethylsulfoxide. This finding suggests that the polyamine site may be located at the intracellular surface of the cell membrane. Our results provide the first evidence for polyamine modulation of the NMDA receptor ionophore complex in a functional physiologic system.

  3. Decreased (/sup 3/H)nitrendipine binding in the brainstem of deoxycorticosterone-NaCl hypertensive rats

    SciTech Connect

    Lee, H.R.; Watson, M.; Yamamura, H.I.; Roeske, W.R.

    1985-09-09

    Binding studies with the 1,4 dihydrophyridine calcium channel antagonist (/sup 3/H)nitrendipine ((/sup 3/H)NTD) were performed in uninephrectomized, deoxycorticosterone (DOCA)-NaCl hypertensive rats and vehicle treated normotensive control littermates. After 6 weeks of treatment, hypertensive (199 mmHg, systolic arterial pressure) DOCA rats showed significantly increased heart, left ventricle, and kidney weight in contrast to normotensive (135 mmHg) controls. (/sup 3/H)NTD binding in the brainstem was significantly reduced (51 +/- 5 fmol/mg protein) in DOCA-NaCl rats, as compared to controls (116 +/- 24 fmol/mg protein). However, no significant differences were found in the (/sup 3/H)NTD dissociation constants for DOCA-NaCl (0.43 +/- 0.03 nM) or control rats (0.62 +/- 0.06 nM). Cerebral cortical and left ventricular tissue showed no significant alterations in receptor binding density or affinity. Specific (/sup 3/H)NTD binding was not significantly altered in other selected brain regions or the atria. These data suggest that alterations in the dihydropyridine binding sites associated with calcium channels in the brainstem may be involved in the etiology of DOCA-NaCl-induced hypertension. 34 references, 1 figure, 2 tables.

  4. 1,3-Di(2-(5-/sup 3/H)tolyl)guanidine: a selective ligand that labels sigma-type receptors for psychotomimetic opiates and antipsychotic drugs

    SciTech Connect

    Weber, E.; Sonders, M.; Quarum, M.; McLean, S.; Pou, S.; Keana, J.F.

    1986-11-01

    Brain sigma-type receptors are thought to mediate hallucinogenic effects of certain benzomorphan opiates in humans. The biochemical characterization of sigma receptors has been difficult because of the lack of potent and selective ligands. We report here the synthesis and characterization of a tritiated, symmetrically substituted guanidine derivative, 1,3-di(2-(5-/sup 3/H)tolyl)guanidine ((/sup 3/H)Tol2Gdn), that binds with high affinity to a single population of binding sites in guinea pig brain membrane preparations. The (/sup 3/H)Tol2Gdn binding site displays stereoselectivity for dextrorotatory optical isomers of benzomorphan opiates known to have sigma-type behavioral effects. Furthermore, the (/sup 3/H)Tol2Gdn binding site has a high affinity for haloperidol and for phenothiazine antipsychotics, which have antihallucinatory properties in humans. The drug-selectivity profile of (/sup 3/H)Tol2Gdn binding closely correlates with the drug-selectivity profile of tritiated (+)-3-(3-hydroxyphenyl)-N-(1-propyl)piperidine (+)-(/sup 3/H)3-PPP) binding to guinea pig brain membrane receptors. (+)-(/sup 3/H)3-PPP has been proposed to be a selective sigma-receptor ligand (Largent, B. L., Gundlach, A. L. and Snyder, S. H. (1984) Proc. Natl. Acad. Sci. USA 82, 4983-4987). Receptor autoradiography using (/sup 3/H)Tol2Gdn on slide-mounted rat and guinea pig brain sections reveals a heterogeneous distribution pattern of enriched binding in limbic and sensorimotor structures of the brain. These results indicate that (/sup 3/H)Tol2Gdn is a selective ligand for the sigma-site. Availability of this sigma-receptor probe should greatly facilitate the physiological, biochemical, and pharmacological characterization of sigma receptors in brain.

  5. 1,3-Di(2-[5-3H]tolyl)guanidine: a selective ligand that labels sigma-type receptors for psychotomimetic opiates and antipsychotic drugs.

    PubMed Central

    Weber, E; Sonders, M; Quarum, M; McLean, S; Pou, S; Keana, J F

    1986-01-01

    Brain sigma-type receptors are thought to mediate hallucinogenic effects of certain benzomorphan opiates in humans. The biochemical characterization of sigma receptors has been difficult because of the lack of potent and selective ligands. We report here the synthesis and characterization of a tritiated, symmetrically substituted guanidine derivative, 1,3-di(2-[5-3H]tolyl)guanidine ([3H]Tol2Gdn), that binds with high affinity to a single population of binding sites in guinea pig brain membrane preparations. The [3H]Tol2Gdn binding site displays stereoselectivity for dextrorotatory optical isomers of benzomorphan opiates known to have sigma-type behavioral effects. Furthermore, the [3H]Tol2Gdn binding site has a high affinity for haloperidol and for phenothiazine antipsychotics, which have antihallucinatory properties in humans. The drug-selectivity profile of [3H]Tol2Gdn binding closely correlates with the drug-selectivity profile of tritiated (+)-3-(3-hydroxyphenyl)-N-(1-propyl)piperidine [+)-[3H]3-PPP) binding to guinea pig brain membrane receptors. (+)-[3H]3-PPP has been proposed to be a selective sigma-receptor ligand [Largent, B. L., Gundlach, A. L. & Snyder, S. H. (1984) Proc. Natl. Acad. Sci. USA 82, 4983-4987]. Receptor autoradiography using [3H]Tol2Gdn on slide-mounted rat and guinea pig brain sections reveals a heterogeneous distribution pattern of enriched binding in limbic and sensorimotor structures of the brain. These results indicate that [3H]Tol2Gdn is a selective ligand for the sigma-site. Availability of this sigma-receptor probe should greatly facilitate the physiological, biochemical, and pharmacological characterization of sigma receptors in brain. Images PMID:2877462

  6. Characterization of the binding of /sup 3/H-SCH 23390, a selective D-1 receptor antagonist ligand, in rat striatum

    SciTech Connect

    Billard, W.; Ruperto, V.; Crosby, G.; Iorio, L.C.; Barnett, A.

    1984-10-29

    A novel benzazepine, SCH 23390, has recently been described as a very potent and selective dopamine D-1 receptor antagonist based on its potent inhibition of dopamine sensitive adenylate cyclase and its selective displacement of /sup 3/H-piflutixol from rat striatal receptor sites. In the present study, the in vitro binding of /sup 3/H-SCH 23390 to specific striatal receptor sites has been characterized. Binding was saturable and stereospecific, and the results of both saturation and competition studies are consistent with the binding of /sup 3/H-SCH 23390 to a single striatal site. A K/sub D/ of 0.53 nM was obtained through Scatchard analysis. Relative potencies of a variety of neuroleptics in competing with /sup 3/H-SCH 23390 and also /sup 3/H-spiperone support an interpretation that the single site to which /sup 3/H-SCH 23390 binds is the D-1 dopamine receptor. Also, the binding capacity of /sup 3/H-SCH 23390 (69 pmoles/gm wet weight) is in agreement with published values for the binding capacities of /sup 3/H-piflutixol and /sup 3/H-flupentixol. These data, coupled with the low level of non-specific binding encountered with this radioligand (4-8% ot total binding at normally employed ligand concentration of 0.3 nM), its high specific activity and its negligible binding to plastic and glass surface make it ideally suited for studying interactions with this receptor.

  7. Dihydropyridine receptor of L-type Ca sup 2+ channels: Identification of binding domains for ( sup 3 H)(+)-PN200-110 and ( sup 3 H)azidopine within the. alpha. 1 subunit

    SciTech Connect

    Striessnig, J.; Murphy, B.J.; Catterall, W.A. )

    1991-12-01

    To identify the binding domain for dihydropyridine Ca{sup 2{plus}} antagonists, skeletal muscle Ca{sup 2{plus}} channels were photolabeled with ({sup 3}H)({plus})-PN200-110 and ({sup 3}H) azidopine. Regions of {alpha}1 photolabeled by these ligands were then identified by antibody mapping of proteolytic fragments. Approximately 50% of the specific labeling by both ligands was incorporated in domain III. ({sup 3}H)Azidopine labeled peptide Gln-989-Arg-1022, which contains a portion of the connecting loop between transmembrane segments IIIS5 and IIIS6 (IIIS5/S6), and peptide Ala-1023-Lys-1077, which contains IIIS6 itself and some adjacent amino acid residues. In contrast, ({sup 3}H)({plus})-PN200-110 labeling occurred almost exclusively in the fragment containing IIIS6. A second site labeled by both ligands was identified in transmembrane segment S6 of domain IV and adjacent residues. It is proposed, based on physiological studies, that these three peptide segments interact to form a receptor site accessible from the extracellular surface of the Ca{sup 2{plus}} channel.

  8. Symmetry and Condensed Matter Physics

    NASA Astrophysics Data System (ADS)

    El-Batanouny, M.; Wooten, F.

    2008-03-01

    Preface; 1. Symmetry and physics; 2. Symmetry and group theory; 3. Group representations: concepts; 4. Group representations: formalism and methodology; 5. Dixon's method for computing group characters; 6. Group action and symmetry projection operators; 7. Construction of the irreducible representations; 8. Product groups and product representations; 9. Induced representations; 10. Crystallographic symmetry and space-groups; 11. Space groups: Irreps; 12. Time-reversal symmetry: color groups and the Onsager relations; 13. Tensors and tensor fields; 14. Electronic properties of solids; 15. Dynamical properties of molecules, solids and surfaces; 16. Experimental measurements and selection rules; 17. Landau's theory of phase transitions; 18. Incommensurate systems and quasi-crystals; References; Bibliography; Index.

  9. Symmetries in laminated composite plates

    NASA Technical Reports Server (NTRS)

    Noor, A. K.

    1976-01-01

    The different types of symmetry exhibited by laminated anisotropic fibrous composite plates are identified and contrasted with the symmetries of isotropic and homogeneous orthotropic plates. The effects of variations in the fiber orientation and the stacking sequence of the layers on the symmetries exhibited by composite plates are discussed. Both the linear and geometrically nonlinear responses of the plates are considered. A simple procedure is presented for exploiting the symmetries in the finite element analysis. Examples are given of square, skew and polygonal plates where use of symmetry concepts can significantly reduce the scope and cost of analysis.

  10. Invariants of broken discrete symmetries.

    PubMed

    Kalozoumis, P A; Morfonios, C; Diakonos, F K; Schmelcher, P

    2014-08-01

    The parity and Bloch theorems are generalized to the case of broken global symmetry. Local inversion or translation symmetries in one dimension are shown to yield invariant currents that characterize wave propagation. These currents map the wave function from an arbitrary spatial domain to any symmetry-related domain. Our approach addresses any combination of local symmetries, thus applying, in particular, to acoustic, optical, and matter waves. Nonvanishing values of the invariant currents provide a systematic pathway to the breaking of discrete global symmetries.

  11. Invariants of Broken Discrete Symmetries

    NASA Astrophysics Data System (ADS)

    Kalozoumis, P. A.; Morfonios, C.; Diakonos, F. K.; Schmelcher, P.

    2014-08-01

    The parity and Bloch theorems are generalized to the case of broken global symmetry. Local inversion or translation symmetries in one dimension are shown to yield invariant currents that characterize wave propagation. These currents map the wave function from an arbitrary spatial domain to any symmetry-related domain. Our approach addresses any combination of local symmetries, thus applying, in particular, to acoustic, optical, and matter waves. Nonvanishing values of the invariant currents provide a systematic pathway to the breaking of discrete global symmetries.

  12. CAF-1-induced oligomerization of histones H3/H4 and mutually exclusive interactions with Asf1 guide H3/H4 transitions among histone chaperones and DNA.

    PubMed

    Liu, Wallace H; Roemer, Sarah C; Port, Alex M; Churchill, Mair E A

    2012-12-01

    Anti-silencing function 1 (Asf1) and Chromatin Assembly Factor 1 (CAF-1) chaperone histones H3/H4 during the assembly of nucleosomes on newly replicated DNA. To understand the mechanism of histone H3/H4 transfer among Asf1, CAF-1 and DNA from a thermodynamic perspective, we developed and employed biophysical approaches using full-length proteins in the budding yeast system. We find that the C-terminal tail of Asf1 enhances the interaction of Asf1 with CAF-1. Surprisingly, although H3/H4 also enhances the interaction of Asf1 with the CAF-1 subunit Cac2, H3/H4 forms a tight complex with CAF-1 exclusive of Asf1, with an affinity weaker than Asf1-H3/H4 or H3/H4-DNA interactions. Unlike Asf1, monomeric CAF-1 binds to multiple H3/H4 dimers, which ultimately promotes the formation of (H3/H4)(2) tetramers on DNA. Thus, transition of H3/H4 from the Asf1-associated dimer to the DNA-associated tetramer is promoted by CAF-1-induced H3/H4 oligomerization.

  13. Electron and Positron Scattering from C3H6 Isomers

    NASA Astrophysics Data System (ADS)

    Makochekanwa, Casten; Sueoka, Osamu; Kimura, Mineo; Hoshino, Masamitsu; Tanaka, Takahiro; Kitajima, Masashi; Tanaka, Hiroshi

    2004-09-01

    Hydrocarbons play an important role in high temperature plasmas in Tokamak fusion devices in plasma processing and many other fields [1]. In this paper we report experiments for 0.4-1000 eV electron and 0.2-1000 eV positron total cross sections (TCS) measured using a linear time-of-flight apparatus [2], and electron differential cross sections (DCS) for elastic, vibrational and electronic excitations covering the ranges 1.5 to 100 eV and 15 deg to 130 deg, measured using the crossed beam and relative flow method [3]. The continuum multiple scattering (CMS) [4] calculations have also been performed for the theoretical analysis of the observed features in our cross sections. We observe the isomer effect in both electron and positron TCSs and DCSs. The presence of a dipole moment in propene molecules shows up in enhanced forward scattering in DCSs, leading to larger TCSs and integral cross sections compared to cyclopropane at energies less than 20 eV. However, both electron and positron TCSs for these two molecules nearly equal each other above 100 eV, i.e. the molecular size effect. [1] W. L. Moragn, Adv. At. Mol. Opt. Phys. 43, 79 (2000). [2] O. Sueoka, S. Mori and A. Hamada, J. Phys. B 27, 1453 (1994). [3] H. Tanaka, L. Boesten, D. Matsunaga and T. Kudo, J. Phys. B 21, 1255 (1988). [4] M. Kimura and H. Sato, Comments At. Mol. Phys. 26, 333 (1991).

  14. Binding of [3H]MK-801 in subcellular fractions of Schistosoma mansoni: evidence for interaction with nicotinic receptors.

    PubMed

    Pessôa, Renata Fittipaldi; Castro, Newton Gonçalves; Noël, François

    2005-05-15

    Several studies have suggested that l-glutamate is a putative neurotransmitter in Schistosoma mansoni. Recently, we detected the presence of low-affinity binding sites for [(3)H]kainic acid in the heterogeneous (P(1)) subcellular fraction of S. mansoni. In an attempt to characterize N-methyl-d-aspartate (NMDA) receptors in this worm, we performed binding assays with [(3)H]MK-801, a NMDA non-competitive antagonist, in the P(1) fraction of adult S. mansoni. In competition experiments, MK-801 (IC(50) approximately 200 microM) and ketamine (IC(50) approximately 500 microM) exhibited a low affinity for the sites labeled with [(3)H]MK-801. Along with the lack of modulation of this binding by glutamatergic agonists and antagonists and the absence of stereoselectivity for MK-801 isomers, these results suggest that [(3)H]MK-801 could label a site different from the classical NMDA receptor in S. mansoni. Based on the evidences that MK-801 interacts with mammalian muscle and central nervous system nicotinic receptors as a low-affinity noncompetitive antagonist, we have investigated the effects of MK-801 on the nicotine-induced flaccid paralysis of the worm, in vivo. The motility of S. mansoni was quantified by image analysis through a measure of displacement of the worm's extremities. In the presence of (-)-nicotine (10-100 microM), we observed an immediate paralysis of the worms, that was inhibited by 1mM MK-801. Besides nicotine, choline (10-50mM) was also able to inhibit the worm's motility. As a conclusion, we suggest that [(3)H]MK-801 binds to nicotinic receptors, and not NMDA receptors, in subcellular fractions of S. mansoni.

  15. Radioactive contamination of the marine environment: Uptake and distribution of3H in Dunaliella bioculata

    NASA Astrophysics Data System (ADS)

    Strack, S.; Bonotto, S.; Kirchmann, R.

    1980-03-01

    The marine flagellate Dunaliella bioculata, which is easily cultivated under laboratory conditions, is a suitable organism for assessing the importance of the radioactive contamination by3H bound to organic molecules. We have studied the uptake of the following tritiated precursors: thymidine-methyl-3H, adenine-2-3H, uridine-5-3H, l-leucine-4-3H, glycine-2-3H, l-arginine-3.4-3H, 1-aspartic acid-2. 3-3H, 1-phenylalanine-2.3-3H, D-glucose-2-3H and D-glucose-6-3H. Under the experimental conditions (2000 lux; incubation time 30 min), all tritiated molecules are taken up by D. bioculata. Their intracellular concentration may reach that of the external medium. However, leucine and adenine accumulate in the algae: their respective concentrations are 10 and 100 times higher than in the culture medium. The molecular distribution of3H has been studied by various biochemical techniques and by sieve chromatography on sepharose 4B. It has been found that more l-leucine-4-3H is incorporated into acid and acetone soluble substances than into proteins. Adenine-2-3H is mainly incorporated into macromolecules of biological significance (RNA, DNA). CsCl gradient centrifugation has shown that the total DNA of Dunaliella is constituted by a major (ϖ=1.707 g/cm3) and by a minor (ϖ=1.693 g/cm3) component.

  16. Serotonin transporter gene polymorphisms and platelet [3H] paroxetine binding in premenstrual dysphoria.

    PubMed

    Melke, J; Westberg, L; Landén, M; Sundblad, C; Eriksson, O; Baghei, F; Rosmond, R; Eriksson, E; Ekman, A

    2003-04-01

    The purpose of this study was to investigate if women with premenstrual dysphoria differ from controls with respect to the number of platelet serotonin transporters, and with respect to three polymorphisms in the gene coding for the serotonin transporter: a 44 base pair insertion/deletion in the promoter region, a variable number of tandem repeats in the second intron, and a single nucleotide polymorphism in the 3' untranslated region. Also, the possible relationship between the three polymorphisms and platelet serotonin transporter density was analyzed. The density of platelet [(3)H]paroxetine binding sites was significantly lower in women with premenstrual dysphoria than in controls, but patients and controls did not differ with respect to allele or genotype frequency for any of the three polymorphisms examined. A significant association between the number of platelet serotonin transporters and the promoter polymorphism was observed, subjects being homozygous for the short (deletion) variant having higher platelet serotonin transporter density than subjects carrying the long (insertion) allele. The results support the assumption that serotonin-related psychiatric disorders-such as premenstrual dysphoria-may be associated with a reduction in platelet [(3)H]paroxetine binding, but argue against the notion that this reduction is due to certain variants of the serotonin transporter gene being more common in patients than in controls.

  17. Symmetry-Breaking Motility

    NASA Astrophysics Data System (ADS)

    Lee, Allen; Lee, Ha Youn; Kardar, Mehran

    2005-09-01

    Locomotion of bacteria by actin polymerization and in vitro motion of spherical beads coated with a protein catalyzing polymerization are examples of active motility. Starting from a simple model of forces locally normal to the surface of a bead, we construct a phenomenological equation for its motion. The singularities at a continuous transition between moving and stationary beads are shown to be related to the symmetries of its shape. Universal features of the phase behavior are calculated analytically and confirmed by simulations. Fluctuations in velocity are shown to be generically non-Maxwellian and correlated to the shape of the bead.

  18. Spectroscopic and magnetic properties of solvatochromic complex of Cu2+ and novel 3H-indolium derivative.

    PubMed

    Gąsiorowska, Monika; Typek, Janusz; Soroka, Jacek Adam; Sawicka, Marta Justyna; Wróblewska, Elwira Katarzyna; Guskos, Niko; Żołnierkiewicz, Grzegorz

    2014-04-24

    A new solvatochromic complex of copper (II) and 3H-indolium (HQIndol) with the formula (HQIndol)3Cu has been synthesised and characterised by elemental analysis, UV-vis, IR spectroscopies, electron paramagnetic resonance (EPR), and static magnetic susceptibility and conductance measurements. The stoichiometry of complex has been determined as 1:3 (M:L) and the binding constant was calculated to be 5.86×10(16) mol(-1) L at 25 °C in CH3OH. Magnetization measurements indicate that (HQIndol)3Cu sample is paramagnetic with spin S=1/2 for which phase transition from paramagnetic to antiferromagnetic has been registered at TN=2.5 K. The symmetry of the EPR spectrum points to elongated tetragonal octahedral geometry of the complex. Examined heterochelate exhibits solvatochromic properties. Blue shift of the vis absorption band with increased solvent polarity is observed, Δν‾max in examined solvents amounts to 1466 cm(-1).

  19. Infrared spectroscopy of gas phase C{sub 3}H{sub 5}{sup +}: The allyl and 2-propenyl cations

    SciTech Connect

    Douberly, Gary E.; Ricks, Allen M.; Schleyer, Paul v. R.; Duncan, Michael A.

    2008-01-14

    C{sub 3}H{sub 5}{sup +} cations are probed with infrared photodissociation spectroscopy in the 800-3500 cm{sup -1} region using the method of rare gas tagging. The ions and their complexes with Ar or N{sub 2} are produced in a pulsed electric discharge supersonic expansion cluster source. Two structural isomers are characterized, namely, the allyl (CH{sub 2}CHCH{sub 2}{sup +}) and 2-propenyl (CH{sub 3}CCH{sub 2}{sup +}) cations. The infrared spectrum of the allyl cation confirms previous theoretical and condensed phase studies of the C{sub 2v} charge delocalized, resonance-stabilized structure. The 2-propenyl cation spectrum is consistent with a C{sub s} symmetry structure having a nearly linear CCC backbone and a hyperconjugatively stabilizing methyl group.

  20. Probing symmetry and symmetry breaking in resonant soft-x-ray fluorescence spectra of molecules

    SciTech Connect

    Glans, P.; Gunnelin, K.; Guo, J.

    1997-04-01

    Conventional non-resonant soft X-ray emission brings about information about electronic structure through its symmetry and polarization selectivity, the character of which is governed by simple dipole rules. For centro-symmetric molecules with the emitting atom at the inversion center these rules lead to selective emission through the required parity change. For the more common classes of molecules which have lower symmetry or for systems with degenerate core orbitals (delocalized over identical sites), it is merely the local symmetry selectivity that provides a probe of the local atomic orbital contribution to the molecular orbital. For instance, in X-ray spectra of first row species the intensities essentially map the p-density at each particular atomic site, and, in a molecular orbital picture, the contribution of the local p-type atomic orbitals in the LCAO description of the molecular orbitals. The situation is different for resonant X-ray fluorescence spectra. Here strict parity and symmetry selectivity gives rise to a strong frequency dependence for all molecules with an element of symmetry. In addition to symmetry selectivity the strong frequency dependence of resonant X-ray emission is caused by the interplay between the shape of a narrow X-ray excitation energy function and the lifetime and vibrational broadenings of the resonantly excited core states. This interplay leads to various observable effects, such as linear dispersion, resonance narrowing and emission line (Stokes) doubling. Also from the point of view of polarization selectivity, the resonantly excited X-ray spectra are much more informative than the corresponding non-resonant spectra. Examples are presented for nitrogen, oxygen, and carbon dioxide molecules.

  1. Classifying symmetry-protected topological phases through the anomalous action of the symmetry on the edge

    NASA Astrophysics Data System (ADS)

    Else, Dominic V.; Nayak, Chetan

    2014-12-01

    It is well known that (1 +1 )-dimensional [(1 +1 )-D] bosonic symmetry-protected topological (SPT) phases with symmetry group G can be identified by the projective representation of the symmetry at the edge. Here we generalize this result to higher dimensions. We assume that the representation of the symmetry on the spatial edge of a (d +1 )-D SPT is local but not necessarily on site, such that there is an obstruction to its implementation on a region with a boundary. We show that such obstructions are classified by the cohomology group Hd +1(G ,U(1 ) ) , in agreement with the classification of bosonic SPT phases proposed in Chen et al. [Science 338, 1604 (2012), 10.1126/science.1227224]. Our analysis allows for a straightforward calculation of the element of Hd +1(G ,U(1 ) ) corresponding to physically meaningful models such as nonlinear σ models with a θ term in the action. SPT phases outside the classification of Chen et al. are those in which the symmetry cannot be represented locally on the edge. With some modifications, our framework can also be applied to fermionic systems in (2 +1 )-D.

  2. Toll-Like Receptor 4-Defective C3H/HeJ Mice Are Not More Susceptible than Other C3H Substrains to Infection with Mycobacterium tuberculosis

    PubMed Central

    Kamath, Arati B.; Alt, Jennifer; Debbabi, Hajer; Behar, Samuel M.

    2003-01-01

    Mycobacterium tuberculosis produces a variety of molecules capable of activating Toll-like receptors, a family of pattern recognition receptors expressed by macrophages and a variety of other cells. To determine whether Toll-like receptor 4 (TLR4) was critical in resistance to M. tuberculosis infection, we compared the morbidity and mortality of TLR4-defective C3H/HeJ mice to those of TLR4-sufficient C3H mouse substrains. TLR4-defective C3H/HeJ mice and TLR4-sufficient C3H/HeSnJ, C3HeB/FeJ, and C3H/HeOuJ mice were infected by the aerosol route with M. tuberculosis. TLR4-defective C3H/HeJ mice had levels of cytokines in their bronchoalveolar lavage fluids and in vitro mycobacterial antigen-specific recall responses similar to those of other C3H mouse substrains. In addition, bacterial replication and long-term survival of mice following infection appeared to be independent of TLR4. Interestingly, C3HeB/FeJ mice were significantly more susceptible to M. tuberculosis infection, indicating that genetic heterogeneity among inbred C3H mouse substrains modifies resistance to infection. Therefore, cautious interpretation is required when the C3H/HeJ strain is used as a model of a TLR4-defective mouse strain, as there are significant allelic differences between C3H/HeJ and other C3H mouse substrains in response to M. tuberculosis infection. With this caveat, our data indicate that TLR4 may not be required for optimal immunity of mice to M. tuberculosis. PMID:12819102

  3. Galactic oscillator symmetry

    NASA Technical Reports Server (NTRS)

    Rosensteel, George

    1995-01-01

    Riemann ellipsoids model rotating galaxies when the galactic velocity field is a linear function of the Cartesian coordinates of the galactic masses. In nuclear physics, the kinetic energy in the linear velocity field approximation is known as the collective kinetic energy. But, the linear approximation neglects intrinsic degrees of freedom associated with nonlinear velocity fields. To remove this limitation, the theory of symplectic dynamical symmetry is developed for classical systems. A classical phase space for a self-gravitating symplectic system is a co-adjoint orbit of the noncompact group SP(3,R). The degenerate co-adjoint orbit is the 12 dimensional homogeneous space Sp(3,R)/U(3), where the maximal compact subgroup U(3) is the symmetry group of the harmonic oscillator. The Hamiltonian equations of motion on each orbit form a Lax system X = (X,F), where X and F are elements of the symplectic Lie algebra. The elements of the matrix X are the generators of the symplectic Lie algebra, viz., the one-body collective quadratic functions of the positions and momenta of the galactic masses. The matrix F is composed from the self-gravitating potential energy, the angular velocity, and the hydostatic pressure. Solutions to the hamiltonian dynamical system on Sp(3,R)/U(3) are given by symplectic isospectral deformations. The Casimirs of Sp(3,R), equal to the traces of powers of X, are conserved quantities.

  4. Applications of chiral symmetry

    SciTech Connect

    Pisarski, R.D.

    1995-03-01

    The author discusses several topics in the applications of chiral symmetry at nonzero temperature. First, where does the rho go? The answer: up. The restoration of chiral symmetry at a temperature T{sub {chi}} implies that the {rho} and a{sub 1} vector mesons are degenerate in mass. In a gauged linear sigma model the {rho} mass increases with temperature, m{sub {rho}}(T{sub {chi}}) > m{sub {rho}}(0). The author conjectures that at T{sub {chi}} the thermal {rho} - a{sub 1}, peak is relatively high, at about {approximately}1 GeV, with a width approximately that at zero temperature (up to standard kinematic factors). The {omega} meson also increases in mass, nearly degenerate with the {rho}, but its width grows dramatically with temperature, increasing to at least {approximately}100 MeV by T{sub {chi}}. The author also stresses how utterly remarkable the principle of vector meson dominance is, when viewed from the modern perspective of the renormalization group. Secondly, he discusses the possible appearance of disoriented chiral condensates from {open_quotes}quenched{close_quotes} heavy ion collisions. It appears difficult to obtain large domains of disoriented chiral condensates in the standard two flavor model. This leads to the last topic, which is the phase diagram for QCD with three flavors, and its proximity to the chiral critical point. QCD may be very near this chiral critical point, and one might thereby generated large domains of disoriented chiral condensates.

  5. [3H]ouabain binding to cultured rat vascular smooth muscle cells.

    PubMed

    Khalil, F; Hopp, L; Searle, B M; Tokushige, A; Tamura, H; Kino, M; Aviv, A

    1984-05-01

    The number of Na+ pump units (Bmax) and the equilibrium dissociation constant (Kd) for ouabain as well as parameters of K+ binding to the Na+ pump were examined in in vitro-grown vascular smooth muscle cells ( VSMC ) derived from Sprague-Dawley rats. The technique to measure these variables utilizes analyses of [3H]ouabain displacement from its VSMC receptors by nonlabeled ouabain and K+. The mean values for Bmax and Kd in the cultured VSMCs were 1.95 X 10(5) receptor sites per single VSMC and 2.68 X 10(-6) M, respectively. The equilibrium dissociation constant for K+ (Ki) was 0.92 mM. K+ binding to the cultured VSMCs demonstrated positive cooperativity with a Hill coefficient (n) of 1.78.

  6. Postsynaptic location of acrylamide-induced modulation of striatal /sup 3/H-spiroperidol binding

    SciTech Connect

    Hong, J.S.; Tilson, H.A.; Agrawal, A.K.; Karoum, F.; Bondy, S.C.

    1982-07-01

    The striata of rats were unilaterally lesioned with kainic acid. After two weeks, rats were exposed to 10 doses of acrylamide (20 mg/kg body weight/dose) over two weeks. Binding of /sup 3/H-spiroperidol to membranes prepared from unoperated striata, was elevated in acrylamide-exposed rats relative to undosed controls. This differential was not apparent when binding was compared in membranes from kainate-treated striata of acrylamide-treated and untreated rats. A parallel acrylamide treatment of unoperated rats had no significant effect on striatal levels of dihydroxyphenylacetic acid and homovanillic acid suggesting that this neurotoxicant failed to affect the presynaptic events of the dopamine system. Thus, the alterations of the striatal dopamine receptor caused by acrylamide, that have been previously reported, appear to be confined to postsynaptic sites.

  7. Synthesis and pharmacological evaluation of [(3)H]HS665, a novel, highly selective radioligand for the kappa opioid receptor.

    PubMed

    Guerrieri, Elena; Mallareddy, Jayapal Reddy; Tóth, Géza; Schmidhammer, Helmut; Spetea, Mariana

    2015-03-18

    Herein we report the radiolabeling and pharmacological investigation of a novel radioligand, the N-cyclobutylmethyl substituted diphenethylamine [(3)H]HS665, designed to bind selectively to the kappa opioid peptide (KOP) receptor, a target of therapeutic interest for the treatment of a variety of human disorders (i.e., pain, affective disorders, drug addiction, and psychotic disorders). HS665 was prepared in tritium-labeled form by a dehalotritiated method resulting in a specific activity of 30.65 Ci/mmol. Radioligand binding studies were performed to establish binding properties of [(3)H]HS665 to the recombinant human KOP receptor in membranes from Chinese hamster ovary cells stably expressing human KOP receptors (CHOhKOP) and to the native neuronal KOP receptor in guinea pig brain membranes. Binding of [(3)H]HS665 was specific and saturable in both tissue preparations. A single population of high affinity binding sites was labeled by [(3)H]HS665 in membranes from CHOhKOP cells and guinea pig brain with similar equilibrium dissociation constants, Kd, 0.45 and 0.64 nM, respectively. Average receptor density of [(3)H]HS665 recognition sites were 5564 and 154 fmol/mg protein in CHOhKOP cells and guinea pig brain, respectively. This study shows that the new radioligand distinguishes and labels KOP receptors specifically in neuronal and cellular systems expressing KOP receptors, making this molecule a valuable tool in probing structural and functional mechanisms governing ligand-KOP receptor interactions in both a recombinant and native in vitro setting.

  8. Bupropion inhibits nicotine-evoked [(3)H]overflow from rat striatal slices preloaded with [(3)H]dopamine and from rat hippocampal slices preloaded with [(3)H]norepinephrine.

    PubMed

    Miller, Dennis K; Sumithran, Sangeetha P; Dwoskin, Linda P

    2002-09-01

    Bupropion, an efficacious antidepressant and smoking cessation agent, inhibits dopamine and norepinephrine transporters (DAT and NET, respectively). Recently, bupropion has been reported to noncompetitively inhibit alpha3beta2, alpha3beta4, and alpha4beta2 nicotinic acetylcholine receptors (nAChRs) expressed in Xenopus oocytes or established cell lines. The present study evaluated bupropion-induced inhibition of native alpha3beta2* and alpha3beta4* nAChRs using functional neurotransmitter release assays, nicotine-evoked [(3)H]overflow from superfused rat striatal slices preloaded with [(3)H]dopamine ([(3)H]DA), and nicotine-evoked [(3)H]overflow from hippocampal slices preloaded with [(3)H]norepinephrine ([(3)H]NE). The mechanism of inhibition was evaluated using Schild analysis. To eliminate the interaction of bupropion with DAT or NET, nomifensine or desipramine, respectively, was included in the superfusion buffer. A high bupropion concentration (100 microM) elicited intrinsic activity in the [(3)H]DA release assay. However, none of the concentrations (1 nM-100 microM) examined evoked [(3)H]NE overflow and, thus, were without intrinsic activity in this assay. Moreover, bupropion inhibited both nicotine-evoked [(3)H]DA overflow (IC(50) = 1.27 microM) and nicotine-evoked [(3)H]NE overflow (IC(50) = 323 nM) at bupropion concentrations well below those eliciting intrinsic activity. Results from Schild analyses suggest that bupropion competitively inhibits nicotine-evoked [(3)H]DA overflow, whereas evidence for receptor reserve was obtained upon assessment of bupropion inhibition of nicotine-evoked [(3)H]NE overflow. Thus, bupropion acts as an antagonist at alpha3beta2* and alpha3beta4* nAChRs in rat striatum and hippocampus, respectively, across the same concentration range that inhibits DAT and NET function. The combination of nAChR and transporter inhibition produced by bupropion may contribute to its clinical efficacy as a smoking cessation agent.

  9. Effect of hemoglobin on the uptake of /sup 3/H-norepinephrine and /sup 3/H-choline chloride into porcine cerebral arteries

    SciTech Connect

    Linnik, M.D.; Lee, T.J.F.

    1986-03-01

    Prolonged constriction of cerebral arteries often follows subarachnoid hemorrhage (SAH). SAH exposes hemoglobin (Hb) to cerebral arteries and Hb has been demonstrated to induce vasoconstriction as well as alter cerebrovascular neurogenic response characteristics. The effect of Hb on uptake of /sup 3/H-norepinephrine (/sup 3/H-NE) and /sup 3/H-choline chloride (/sup 3/H-ChCl) into porcine cerebral arteries was therefore examined. 0.5 to 50 ..mu..M porcine Hb caused a dose-dependent inhibition of /sup 3/H-NE uptake into the anterior (ANT), internal carotid (IC) and middle cerebral (MC) arteries of the pig. IC/sub 50/ values for uptake inhibition were: ANT, 31 ..mu..M; IC, 34 ..mu..M; MC, 37 ..mu..M. Porcine serum albumin (PSA) in the same concentration range also caused a decrease in /sup 3/H-NE uptake. An examination of protein-ligand interactions using column chromatography demonstrated binding of /sup 3/H-NE by both Hb and PSA. This protein binding may be responsible for part of the uptake inhibition. Hb and PSA had little effect on /sup 3/H-ChCl uptake into these arteries.

  10. The effect of phencyclidine on [3H]GABA and [3H]flunitrazepam binding in the brain of naive and handling-habituated rats.

    PubMed

    Lillrank, S M; Oja, S S; Saransaari, P

    1995-01-01

    The effects of handling and handling combined with phencyclidine (PCP) treatment on GABAergic neurotransmission were studied in Sprague-Dawley rats. The animal material consisted of handling-habituated (HH, for 11 d), acutely handled (naive, N), handling-habituated and PCP-treated (10 mg kg-1 i.p., HH + PCP) and acutely handled (naive) PCP-treated (N + PCP) and unhandled 'control' rats. The binding of [3H]GABA and [3H]flunitrazepam (FLU) was studied with membranes and the release of [3H]GABA with slices prepared from the striatum and frontal cortex. In the striatum the maximal binding capacity (Bmax) and the binding constant (KD) of [3H]GABA were the same in N and HH rats, but in the frontal cortex KD was lower in N rats. KD constants of [3H]FLU were significantly lower in both brain areas in N rats than in HH rats. After PCP treatment both Bmax and KD for [3H]FLU increased in these two brain areas in handling-habituated rats, whereas Bmax of [3H]GABA diminished. Neither handling nor PCP had any effect on [3H]GABA release from striatal and frontal cortical slices. Handling prior to killing thus affects differently the GABAergic parameters studied and modulates the PCP-induced effects.

  11. [Symmetries and homologies of Geomerida].

    PubMed

    Zarenkov, N A

    2005-01-01

    The symmetry of Earths life cover (Geomerida) was described generally by L.A. Zenkevich (1948). It coincides with the symmetry of geographic cover. Its symmetry elements are equatorial plane and three meridonal planes corresponded to oceans and continents. The hypsographic curve with point of inflection (symmetry element) on 3 km depth line should be added to these elements. The plankton and benthos communities as well as fauna of taxons are distributed symmetrically according these symmetry elements. Zenkevich model was successfully extrapolated to plankton by K.V. Beklemishev (1967, 1969) and to abyssal benthos by Sokolova M.N. (1986). The plankton communities inhabiting symmetrically located macrocirculations are considered as homologous. The character of circulation determines the trophic structure of plankton and benthos. In the case of high productivity of plankton, benthic grazing animals feed on sedimented particles have bilateral symmetric mouthpart. Otherwise they have to acquire food from water column and use cyclomeric mouthpart. Thus, the symmetry of macrocirculations determines the symmetry distribution of benthic animals with two major symmetries of mouthparts. The peculiarities of organisms' symmetry are discussed in the context of Pierre Curie principle and the ideas of K.V. Beklemishev concerning evolution of morphological axes.

  12. Quartic canonical force field in curvilinear internal coordinates for XY3 (D3h) molecules. The case of the BH3 molecule.

    PubMed

    Ródenas, Consuelo Rosales; Quesada, Juana Vázquez; Torres, Emilio Martínez; González, Juan Jesús López

    2014-06-01

    Using the canonical force field theory, expressions of quadratic, cubic, and quartic canonical force constants are obtained for XY3 (D3h) molecules in curvilinear redundant coordinates, i.e., simple valence internal coordinates (VICs), in terms of force constants in normal coordinates and in independent symmetry coordinates. To carry out this task, it was previously necessary to obtain for the first time the non-linear redundancy relation and the corresponding orthogonal projection onto the pure vibrational manifold for XY3 (D3h) molecules corresponding to a set of seven VICs. As an application, the quartic canonical force field in curvilinear redundant internal coordinates of BH3 is determined from ab initio force fields in normal coordinates calculated at the coupled-cluster singles and doubles level with perturbative treatment of the triples in conjunction with a triple- and quadruple-ζ size basis set. This anharmonic force field so obtained for the borane molecule, and in general for XY3 (D3h) molecules, is uniquely defined (therefore in an unambiguous form) and depending on the same number of parameters, i.e., force constants, when independent coordinates (natural or symmetry) are used in its description.

  13. Pharmacological Characterization of [3H]CHIBA-3007 Binding to Glycine Transporter 1 in the Rat Brain

    PubMed Central

    Zhang, Jichun; Wu, Jin; Toyohara, Jun; Fujita, Yuko; Chen, Hongxian; Hashimoto, Kenji

    2011-01-01

    Glycine transporter-1 (GlyT-1) in glial cells regulates extracellular levels of glycine, which acts as an obligatory co-agonist at the N-methyl-D-aspartate (NMDA) receptors in the brain. In the present study, we developed a novel radioligand, [3H]3-chloro-N-((S)-((R)-1-methylpiperidin-2-yl)(thiophen- 3-yl)methyl)-4- (trifluoromethyl)picolinamide ([3H]CHIBA-3007), for studying GlyT-1 in the brain. The presence of a single saturable high-affinity binding component for [3H]CHIBA-3007 binding to the rat brain membranes was detected. Scatchard analysis revealed an apparent equilibrium dissociation constant (Kd) of 1.61±0.16 nM and a maximal number of binding sites (Bmax) of 692.8±22.8 fmol/mg protein (mean ± SEM, n = 3). The specific binding of [3H]CHIBA-3007 was inhibited by a number of GlyT-1 inhibitors, such as CHIBA-3007, desmethyl-CHIBA-3007, CHIBA-3008, SSR504734, NFPS/ALX5407, LY2365109 and Org24598, consistent with the pharmacological profiles of GlyT-1 inhibitors. Interestingly, the potency of eight GlyT-1 inhibitors (CHIBA-3007, desmethyl-CHIBA-3007, NFPS/ALX5407, LY2365109, Org24598, SSR504734, sarcosine, and glycine) for blocking in vitro specific binding of [3H]CHIBA-3007 was significantly correlated with the potency of these inhibitors for inhibiting [14C]glycine uptake in the rat brain membranes. In contrast, the GlyT-2 inhibitor ALX1393 exhibited very weak for [3H]CHIBA-3007 binding. Furthermore, the regional distribution of [3H]CHIBA-3007 binding in the rat brain was similar to the previously reported distribution of GlyT-1. The present findings suggest that [3H]CHIBA-3007 would be a useful new radioligand for studying GlyT-1 in the brain. PMID:21731704

  14. From Molecular Point Group Symmetry to Space Group Symmetry.

    ERIC Educational Resources Information Center

    Hathaway, Brian

    1979-01-01

    Describes undergraduate chemistry curricula in which the student is asked to either build a model of one asymmetric unit in the unit cell and to indicate the positions of the symmetry-related units by putting in key atoms, or to identify on a prebuild model the asymetric and symmetry-related units. (BB)

  15. Neurons in the brain of the male cynomolgus monkey accumulate /sup 3/H-medroxyprogesterone acetate (MPA)

    SciTech Connect

    Michael, R.P.; Bonsall, R.W.; Rees, H.D.

    1986-03-01

    MPA is a synthetic progestin with androgen-depleting activity. It is used clinically to reduce sexual motivation and aggression in male sex offenders. The mechanisms for its behavioral effects are not known. The authors used steroid autoradiography to help identify sites where MPA may act in the brain of male primates. Twenty-four hours after castration, two adult male cynomolgus macaques, weighing 4.9 and 6.6 kg, were administered 5 mCi /sup 3/H-MPA (NEN, 47.7 Ci/mmol) i.v., and were killed 1 h later. Left sides of the brains and samples of pituitary glands were frozen and 4-micron sections were cut and processed for thaw-mount autoradiography. Radioactivity was concentrated in the nuclei of many neutrons in the ventromedial hypothalamic nucleus (n.), arcuate n., medial preoptic n., and anterior hypothalamic area. Virtually no labeled cells were seen in the bed n. of stria terminalis, lateral septal n., amygdala, or pituitary gland. Right sides of the brains were analyzed by HPLC which demonstrated that 98% of the radioactivity in cell nuclei from the hypothalamus was in the form of unmetabolized /sup 3/H-MPA. The distribution of labelling in the brain following /sup 3/H-MPA administration resembled that previously seen following /sup 3/H-ORG 2058 in female cynomolgus monkeys. These data indicate that MPA has a circumscribed localization in the brain.

  16. A unique binding mode enables MCM2 to chaperone histones H3-H4 at replication forks.

    PubMed

    Huang, Hongda; Strømme, Caroline B; Saredi, Giulia; Hödl, Martina; Strandsby, Anne; González-Aguilera, Cristina; Chen, Shoudeng; Groth, Anja; Patel, Dinshaw J

    2015-08-01

    During DNA replication, chromatin is reassembled by recycling of modified old histones and deposition of new ones. How histone dynamics integrates with DNA replication to maintain genome and epigenome information remains unclear. Here, we reveal how human MCM2, part of the replicative helicase, chaperones histones H3-H4. Our first structure shows an H3-H4 tetramer bound by two MCM2 histone-binding domains (HBDs), which hijack interaction sites used by nucleosomal DNA. Our second structure reveals MCM2 and ASF1 cochaperoning an H3-H4 dimer. Mutational analyses show that the MCM2 HBD is required for MCM2-7 histone-chaperone function and normal cell proliferation. Further, we show that MCM2 can chaperone both new and old canonical histones H3-H4 as well as H3.3 and CENPA variants. The unique histone-binding mode of MCM2 thus endows the replicative helicase with ideal properties for recycling histones genome wide during DNA replication.

  17. SKF 525-A and cytochrome P-450 ligands inhibit with high affinity the binding of ( sup 3 H)dextromethorphan and. sigma. ligands to guinea pig brain

    SciTech Connect

    Klein, M.; Canoll, P.D.; Musacchio, J.M. )

    1991-01-01

    The DM{sub 1}/{sigma}{sub 1} site binds dextromethorphan (DM) and {sigma} receptor ligands. The broad binding specificity of this site and its peculiar subcellular distribution prompted us to explore the possibility that this site is a member of the cytochrome P-450 superfamily of enzymes. We tested the effects of the liver microsomal monooxygenase inhibitor SKF 525-A (Proadifen), and other P-450 substrates on the binding of ({sup 3}H)dextromethorphan, ({sup 3}H)3- (3-Hydroxyphenyl) -N- (1-propyl) piperidine and (+)-({sup 3}H)1,3-Di-o-tolyl-guanidine (({sup 3}H)DTG) to the guinea pig brain. SKF 525-A, l-lobeline and GBR-12909 inhibited the binding of the three labeled ligands with nM affinity. Each drug has identical nM K{sub i} values for the high-affinity site labeled by the three ligands. This indicated that they displaced the labeled ligands from the common DM{sub 1}{sigma}{sub 1} site. Debrisoquine and sparteine, prototypical substrates for liver debrisoquine 4-hydroxylase, displayed K{sub i} values of 9-13 and 3-4 {mu}M respectively against the three labeled ligands. These results, the broad specificity of the DM{sub 1}/{sigma}{sub 1} binding site, and its peculiar subcellular distribution, raises the possibility that this binding site is a member of the cytochrome P-450 superfamily of isozymes, rather than a neurotransmitter receptor.

  18. Symmetry reduction related with nonlocal symmetry for Gardner equation

    NASA Astrophysics Data System (ADS)

    Ren, Bo

    2017-01-01

    Based on the truncated Painlevé method or the Möbious (conformal) invariant form, the nonlocal symmetry for the (1+1)-dimensional Gardner equation is derived. The nonlocal symmetry can be localized to the Lie point symmetry by introducing one new dependent variable. Thanks to the localization procedure, the finite symmetry transformations are obtained by solving the initial value problem of the prolonged systems. Furthermore, by using the symmetry reduction method to the enlarged systems, many explicit interaction solutions among different types of solutions such as solitary waves, rational solutions, Painlevé II solutions are given. Especially, some special concrete soliton-cnoidal interaction solutions are analyzed both in analytical and graphical ways.

  19. Symmetry and surface symmetry energies in finite nuclei

    SciTech Connect

    Lee, S. J.; Mekjian, A. Z.

    2010-12-15

    A study of the properties of the symmetry energy of nuclei is presented based on density-functional theory. Calculations for finite nuclei are given so that the study includes isospin-dependent surface symmetry considerations as well as isospin-independent surface effects. Calculations are done at both zero and nonzero temperature. It is shown that the surface symmetry energy term is the most sensitive to the temperature while the bulk energy term is the least sensitive. It is also shown that the temperature-dependence terms are insensitive to the force used and even more insensitive to the existence of neutron skin. Results for a symmetry energy with both volume and surface terms are compared with a symmetry energy with only volume terms along the line of {beta} stability. Differences of several MeV are shown over a good fraction of the total mass range in A. Also given are calculations for the bulk, surface and Coulomb terms.

  20. NIF symmetry capsule modeling

    NASA Astrophysics Data System (ADS)

    Weber, S. V.; Casey, D. T.; Pino, J. E.; Rowley, D. P.; Smalyuk, V. A.; Spears, B. K.; Tipton, R. E.

    2013-10-01

    NIF CH ablator symmetry capsules are filled with hydrogen or helium gas. SymCaps have more moderate convergence ratios ~ 15 as opposed to ~ 35 for ignition capsules with DT ice layers, and better agreement has been achieved between simulations and experimental data. We will present modeling of capsules with CD layers and tritium fill, for which we are able to match the dependence of DT yield on recession distance of the CD layer from the gas. We can also match the performance of CH capsules with D3 He fill. The simulations include surface roughness, drive asymmetry, a mock-up of modulation introduced by the tent holding the capsule, and an empirical prescription for ablator-gas atomic mix. This work performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344.

  1. Reductions in (/sup 3/H)nicotinic acetylcholine binding in Alzheimer's disease and Parkinson's disease: an autoradiographic study

    SciTech Connect

    Whitehouse, P.J.; Martino, A.M.; Wagster, M.V.; Price, D.L.; Mayeux, R.; Atack, J.R.; Kellar, K.J.

    1988-05-01

    In Alzheimer's disease (AD) and Parkinson's disease (PD), dysfunction in the basal forebrain cholinergic system is accompanied by a consistent loss of presynaptic cholinergic markers in cortex, but changes in cholinergic receptor binding sites are poorly understood. In the present study, we used receptor autoradiography to map the distribution of nicotinic (/sup 3/H)acetylcholine binding sites in cortices of individuals with AD and PD and matched control subjects. In both diseases, a profound loss of nicotinic receptors occurs in all cortical layers, particularly the deepest layers.

  2. Photoaffinity labeling of opiate receptors using intrinsically photoactive /sup 3/H-opiates

    SciTech Connect

    Kooper, G.N.; Levinson, N.R.; Copeland, C.F.; Bowen, W.D.

    1988-03-01

    Opiate receptors in rat and cow brain membranes have been labeled irreversibly using the intrinsic photolability of 3H-opiates. Membranes were incubated with 3H-ligand and then irradiated with UV light of 254 nm. Nonspecific binding was determined in the presence of 10 microM unlabeled levallorphan. Irreversible binding was defined as binding which survived heat or acid denaturation of membranes. Specific incorporation of label into denatured samples was observed only when unbound or loosely bound 3H-ligand was washed free from the membranes prior to irradiation. There was a general correlation between photosensitivity of the 3H-ligand and its ability to photolabel receptors. Hence, photolabeling presumably results by covalent attachment of highly reactive species generated during photochemical decomposition of ligand. With 3H-etorphine, optimal irradiation time was 5 min. In addition to 3H-etorphine, receptors could be labeled irreversibly with 3H-oxymorphone, 3H-dihydromorphine, and 3H-ethylketocyclazocine. Of the specific binding present in irradiated, nondenatured samples, 45-60% remained attached to receptors upon denaturation. 3H-Ethylketocyclazocine exhibited an 86% yield of incorporation. Signal-to-noise levels of 50-80% could be achieved in denatured samples. Therefore, this method provides a means of covalently labeling opiate receptors in high yield and with high signal-to-noise ratios. The opioid peptides, 3H-D-Ala2,D-Leu5-enkephalin, 3H-D-Ser2,Leu5,Thr6-enkephalin, 3H-D-Ala2,Met5-enkephalin amide, and 3H-D-Ala2,N-MePhe4,Gly-ol5-enkephalin, as well as the benzomorphan, 3H-bremazocine, apparently lack the structural characteristics which allow photolabeling.

  3. Characterization of the binding of [3H]CGP54626 to GABAB receptors in the male bullfrog (Rana catesbeiana).

    PubMed

    Asay, Matthew J; Boyd, Sunny K

    2006-06-13

    Gamma-aminobutyric acid (GABA) is the main inhibitory neurotransmitter in the vertebrate brain. GABA activates both ionotropic (GABA(A)) and metabotropic (GABA(B)) receptors in mammals. Whether non-mammalian vertebrates possess receptors with similar characteristics is not well understood. We used a mammalian GABA(B)-specific antagonist to determine the pharmacology of putative receptors in the brain of an anuran amphibian, the male bullfrog (Rana catesbeiana). Receptor binding assays with the antagonist [(3)H]CGP54626 revealed a single class of high affinity binding sites (with a K(D) of 2.97 nM and a B(max) of 2619 fmol/mg protein). Binding was time- and temperature-dependent, saturable and specific. Specific binding of [(3)H]CGP54626 was inhibited by several mammalian GABA(B) receptor agonists and antagonists. The rank order potency of agonists was: GABA = SKF97541 > (R)-Baclofen > 3-APPA. The rank order for antagonists was: CGP54626 = CGP55845 > CGP52432 > CGP35348. The GABA(A) receptor ligands muscimol and SR95531 had very low affinity for [(3)H]CGP54626 binding sites, while bicuculline compounds had no affinity. Binding of GABA was positively modulated by CGP7930. Taurine did not allosterically modulate GABA binding but did inhibit [(3)H]CGP54626 binding in a linear fashion. Bullfrog brain thus possesses binding sites with significant similarity to mammalian GABA(B) receptors. These receptors differ from mammalian receptors, however, in dissociation kinetics, ligand specificity and allosteric modulation.

  4. Decreased [(3)H]spiperone binding in the anterior cingulate cortex of schizophrenia patients: an autoradiographic study.

    PubMed

    Zavitsanou, K; Huang, X F

    2002-01-01

    Abnormalities in the anterior cingulate cortex have been reported in patients with schizophrenia, and have been implicated in the pathophysiology of this disorder. In the present study, we have examined antipsychotic-sensitive binding sites in the left anterior cingulate cortex of schizophrenia patients and controls. Using quantitative autoradiography and [(3)H]spiperone as a ligand, both saturation and competition experiments were performed in post-mortem brain tissue obtained from six schizophrenia and six control cases. Saturation experiments revealed that the maximum number of [(3)H]spiperone binding sites was significantly reduced by 31% in the schizophrenia group as compared to the control group (65.3+/-5.6 fmol/mg tissue versus 94.2+/-7.3 fmol/mg tissue). Increased dissociation constant was also observed in the schizophrenia group (2.2+/-0.4 nM versus 1.3+/-0.2 nM), but was not statistically significant (P=0.07). Competition experiments were performed in order to examine the pharmacological profile of [(3)H]spiperone binding, and revealed that: (i) displacement of [(3)H]spiperone binding by clozapine and mianserin was significantly reduced in the schizophrenia group as compared to the control group (-26% and -16% respectively); (ii) the order of displacement potency of the drugs tested was: haloperidol>mianserin>butaclamol approximately risperidone>clozapine>2-amino-6,7-dihydroxy-1,2,3,4-tetrahydronaphthalene. Our results suggest a reduction of antipsychotic-sensitive binding sites in the anterior cingulate cortex of patients with schizophrenia. Such abnormality could lead to an imbalance in neurotransmitter regulation in the anterior cingulate cortex which may contribute to the emergence of some symptoms of schizophrenia.

  5. Bilateral symmetry across Aphrodite Terra

    NASA Technical Reports Server (NTRS)

    Crumpler, L. S.; Head, J. W.; Campbell, D. B.

    1987-01-01

    There are three main highland areas on Venus: Beta Regio, Ishtar Terra and Aphrodite Terra. The latter is least known and the least mapped, yet existing analyses of Aphrodite Terra based on available Pioneer-Venus orbiter data suggest that it may be the site of extensive rifting. Some of the highest resolution (30 km) PV data (SAR) included most of the western half of Aphrodite Terra. Recent analysis of the SAR data together with Arecibo range-doppler topographic profiling (10 X 100 km horizontal and 10 m vertical resolution) across parts of Aphrodite, further characterized the nature of possible tectonic processes in the equatorial highlands. The existence of distinct topographic and radar morphologic linear discontinuities across the nearly east-west strike of Aphrodite Terra is indicated. Another prominent set of linear features is distinctly parallel to and orthogonal to the ground tracks of the PV spacecraft and are not included because of the possibility that they are artifacts. Study of the northwest trending cross-strike discontinuities (CSD's) and the nature of topographic and morphologic features along their strike suggest the presence of bilateral topographic and morphologic symmetry about the long axis of Aphrodite Terra.

  6. EPR Spectra of Some Cu2+-Doped Metal Carbonates and Disorder Phase Transition in K3H(CO3)2

    NASA Astrophysics Data System (ADS)

    Demir, Dilek; Köksal, Fevzi; Kazak, Canan; Köseoğlu, Rahmi

    2009-02-01

    Cu2+-doped K3H(CO3)2, Rb2CO3, and Rb2KH(CO3)2 single crystals were investigated by electron paramagnetic resonance (EPR) spectroscopy. The EPR spectrum of K3H(CO3)2 indicates two different sites for Cu2+ at room and at low temperatures. But the signals for the two sites overlap at 318 K which is attributed to a disorder phase transition. Each of the other compounds exhibits one site. The Cu2+ ion seems to substitute the K+ and Rb+ ions and the charge compensations are fulfilled by the proton vacancies in K3H(CO3)2, and another K+ and Rb+ in the other compounds. The spin Hamiltonian parameters g and A for each compound are determined and discussed.

  7. Symmetry in Sign Language Poetry

    ERIC Educational Resources Information Center

    Sutton-Spence, Rachel; Kaneko, Michiko

    2007-01-01

    This paper considers the range of ways that sign languages use geometric symmetry temporally and spatially to create poetic effect. Poets use this symmetry in sign language art to highlight duality and thematic contrast, and to create symbolic representations of beauty, order and harmony. (Contains 8 tables, 14 figures and 6 notes.)

  8. Symmetry in the Car Park

    ERIC Educational Resources Information Center

    Hancock, Karen

    2007-01-01

    In this article, the author presents a lesson on rotational symmetry which she developed for her students. The aim of the lesson was "to identify objects with rotational symmetry in the staff car park" and the success criteria were "pictures or sketches of at least six objects with different orders of rotation". After finding examples of…

  9. Asymptotic symmetries on Killing horizons

    NASA Astrophysics Data System (ADS)

    Koga, Jun-Ichirou

    2001-12-01

    We investigate asymptotic symmetries regularly defined on spherically symmetric Killing horizons in Einstein theory with or without the cosmological constant. These asymptotic symmetries are described by asymptotic Killing vectors, along which the Lie derivatives of perturbed metrics vanish on a Killing horizon. We derive the general form of the asymptotic Killing vectors and find that the group of asymptotic symmetries consists of rigid O(3) rotations of a horizon two-sphere and supertranslations along the null direction on the horizon, which depend arbitrarily on the null coordinate as well as the angular coordinates. By introducing the notion of asymptotic Killing horizons, we also show that local properties of Killing horizons are preserved not only under diffeomorphisms but also under nontrivial transformations generated by the asymptotic symmetry group. Although the asymptotic symmetry group contains the Diff(S1) subgroup, which results from supertranslations dependent only on the null coordinate, it is shown that the Poisson brackets algebra of the conserved charges conjugate to asymptotic Killing vectors does not acquire nontrivial central charges. Finally, by considering extended symmetries, we discuss the fact that unnatural reduction of the symmetry group is necessary in order to obtain the Virasoro algebra with nontrivial central charges, which is not justified when we respect the spherical symmetry of Killing horizons.

  10. The effect of delta9-tetrahydrocannabinol on the conversion of [3H]trypotphan to 5-[3H] hydroxytryptamine in the mouse brain.

    PubMed

    Johnson, K M; Dewey, W L

    1978-10-01

    The effects of a 30-min pretreatment with varying doses of delta9-tetrahydrocannibinol (delta9-THC) on the synthesis of 5-[3H]hydroxytryptamine (5-[3H]HT) from an intravenous 10-min pulse of L-[3H]tryptophan ([3H]try) were measured in the mouse brain. We also determined the effects of delta9-THC on several parameters believed to influence the synthesis of brain 5-HT, including total and free plasma tryptophan and the high-affinity synaptosomal uptake of tryptophan. Delta9-THC was found to increase the amount of [3H]try accumulated by the brain as well as the amount of 5-[3H]HT synthesized. This effect was greater at intermediate doses than at the highest dose tested. However, delta9-THC was determined to have no effect on the actual rate of conversion of [3H]try into 5-[3H]HT at any dose tested. Delta9-THC had no effect on either plasma tyrosine ot free tryptophan levels. However, delta9-THC decreased total plasma tryptophan at low and intermediate doses, but had no effect at the highest dose tested. Synaptosomal uptake of [3H]try was unaffected by pretreatment with delta9-THC at any dose tested. These data suggest that delta9-THC increases the synthesis of 5-HT, not by altering the actual rate of conversion of tryptophan to 5-HT, but by altering, via an unknown mechanism, the quantity of tryptophan available for conversion to 5-HT.

  11. Hyperbolic-symmetry vector fields.

    PubMed

    Gao, Xu-Zhen; Pan, Yue; Cai, Meng-Qiang; Li, Yongnan; Tu, Chenghou; Wang, Hui-Tian

    2015-12-14

    We present and construct a new kind of orthogonal coordinate system, hyperbolic coordinate system. We present and design a new kind of local linearly polarized vector fields, which is defined as the hyperbolic-symmetry vector fields because the points with the same polarization form a series of hyperbolae. We experimentally demonstrate the generation of such a kind of hyperbolic-symmetry vector optical fields. In particular, we also study the modified hyperbolic-symmetry vector optical fields with the twofold and fourfold symmetric states of polarization when introducing the mirror symmetry. The tight focusing behaviors of these vector fields are also investigated. In addition, we also fabricate micro-structures on the K9 glass surfaces by several tightly focused (modified) hyperbolic-symmetry vector fields patterns, which demonstrate that the simulated tightly focused fields are in good agreement with the fabricated micro-structures.

  12. Characterization of L-[3H]nicotine binding in human cerebral cortex: comparison between Alzheimer's disease and the normal.

    PubMed

    Flynn, D D; Mash, D C

    1986-12-01

    Putative nicotine receptors in the human cerebral cortex were characterized with L-[3H]nicotine, L-[3H]Nicotine binding was enhanced by the addition of Ca2+ and abolished in the presence of Na3EDTA. Association and dissociation of the ligand were rapid at 25 degrees C with t1/2 values of 2 and 3 min, respectively. Saturation binding analysis revealed an apparent single class of sites with a dissociation constant of 5.6 nM and a Hill coefficient of 1.05. There was no effect of postmortem interval on the density of binding sites assayed up to 24 h in rat frontoparietal cortex. Nicotine binding in human cortical samples was also unaltered by increasing sampling delay. In human cortical membranes, binding site density decreased with normal aging. Receptor affinity and concentration in samples of frontal cortex (Brodmann area 10) from patients with Alzheimer's disease were comparable to age-matched control values. Samples of infratemporal cortex (Brodmann area 38) from patients with Alzheimer's disease had a 50% reduction in the number of L-[3H]nicotine sites. Choline acetyltransferase activity was significantly decreased in both cortical areas. Enzyme activities in the temporal pole were reduced to 20% of control values. These data indicate that postsynaptic nicotine receptors are spared in the frontal cortex in Alzheimer's disease. In the infratemporal cortex, significant numbers of receptors remain despite the severe reduction in choline acetyltransferase activity. Replacement therapy directed at these sites may be warranted in Alzheimer's disease.

  13. Abundance Anomaly of the 13C Isotopic Species of c-C3H2 in the Low-mass Star Formation Region L1527

    NASA Astrophysics Data System (ADS)

    Yoshida, Kento; Sakai, Nami; Tokudome, Tomoya; López-Sepulcre, Ana; Watanabe, Yoshimasa; Takano, Shuro; Lefloch, Bertrand; Ceccarelli, Cecilia; Bachiller, Rafael; Caux, Emmanuel; Vastel, Charlotte; Yamamoto, Satoshi

    2015-07-01

    The rotational spectral lines of c-C3H2 and two kinds of the 13C isotopic species, c-{}13{{CCCH}}2 ({C}2v symmetry) and c-{{CC}}13{{CH}}2 (Cs symmetry), have been observed in the 1-3 mm band toward the low-mass star-forming region L1527. We have detected 7, 3, and 6 lines of c-C3H2, c-{}13{{CCCH}}2, and c-{{CC}}13{{CH}}2, respectively, with the Nobeyama 45 m telescope and 34, 6, and 13 lines, respectively, with the IRAM 30 m telescope, where seven, two, and two transitions, respectively, are observed with both telescopes. With these data, we have evaluated the column densities of the normal and 13C isotopic species. The [c-C3H2]/[c-{}13{{CCCH}}2] ratio is determined to be 310 ± 80, while the [c-C3H2]/[c-{{CC}}13{{CH}}2] ratio is determined to be 61 ± 11. The [c-C3H2]/[c-{}13{{CCCH}}2] and [c-C3H2]/[c-{{CC}}13{{CH}}2] ratios expected from the elemental 12C/13C ratio are 60-70 and 30-35, respectively, where the latter takes into account the statistical factor of 2 for the two equivalent carbon atoms in c-C3H2. Hence, this observation further confirms the dilution of the 13C species in carbon-chain molecules and their related molecules, which are thought to originate from the dilution of 13C+ in the gas-phase C+ due to the isotope exchange reaction: {}13{{{C}}}++{CO}\\to {}13{CO}+{{{C}}}+. Moreover, the abundances of the two 13C isotopic species are different from each other. The ratio of c-{}13{{CCCH}}2 species relative to c-{{CC}}13{{CH}}2 is determined to be 0.20 ± 0.05. If 13C were randomly substituted for the three carbon atoms, the [c-{}13{{CCCH}}2]/[c-{{CC}}13{{CH}}2] ratio would be 0.5. Hence, the observed ratio indicates that c-{{CC}}13{{CH}}2 exists more favorably. Possible origins of the different abundances are discussed. Based on observations carried out with the IRAM 30 m Telescope and the NRO 45 m Telescope. IRAM is supported by INSU/CNRS (France), MPG (Germany), and IGN (Spain). NRO is a branch of the National Astronomical Observatory of Japan

  14. The sites of Gd3 + in the luminescent matrix La1 - xGdxMgAl11O19: Single crystal structure determination and site-selective excitation of Gd3 +

    NASA Astrophysics Data System (ADS)

    Salem, Y.; Linares, C.; Jacquier, B.; Saine, M. C.; Gasperin, M.; Lejus, A. M.; Vivien, D.

    1990-11-01

    Single crystals of La1-xGdxMgAl11O19 for x=0.02 to 1 have been grown from the melt by the Verneuil (flame fusion) method. The localization of Gd3+ ions in the matrix has been obtained using x-ray diffraction and Gd3+ fluorescence techniques giving the average and the local structure of the material. The resolution of the crystal structure, of La0.4Gd0.6MgAl11O19 homolog, indicates that this compound is of the distorted magnetoplumbite (MP) type (hexagonal P63/ mmc). Lanthanide ions lie in the mirror plane in two kinds of sites: the (2d) regular MP one (D3h symmetry) occupied by La3+ ions, the distorted (12j) one (Cs symmetry) partially filled up and containing only Gd3+. Some oxygen ions of the Ln coordination polyhedron may be missing leading to a lowering of the true symmetry of the sites. Site selective excitation of the fluorescence of Gd3+ and emission spectra have been carried out on crystals with different x values. It indicates that Gd3+ ions are distributed mainly among two sites, A and B. Crystal field analysis of the splitting of the 6P terms of Gd3+ determined on the excitation spectra show that site A is close to the ideal D3h symmetry while site B is a strongly distorted site. This leads to the identification A=(2d), B=(12j). The occupancy is larger for site B than for site A in agreement with the refinement of the structure. Selective laser excitation into the A site induces emission of the B sites as a result of energy transfer which is demonstrated by the fluorescence decay. No evidence of energy migration is found for gadolinium content up to 100%. Fluorescence spectroscopy and crystal structure determination appear complementary to obtain a detailed description of the sites of Gd3+ in La1-xGdxMgAl11O19.

  15. PT Symmetry and Spontaneous Symmetry Breaking in a Microwave Billiard

    NASA Astrophysics Data System (ADS)

    Bittner, S.; Dietz, B.; Günther, U.; Harney, H. L.; Miski-Oglu, M.; Richter, A.; Schäfer, F.

    2012-01-01

    We demonstrate the presence of parity-time (PT) symmetry for the non-Hermitian two-state Hamiltonian of a dissipative microwave billiard in the vicinity of an exceptional point (EP). The shape of the billiard depends on two parameters. The Hamiltonian is determined from the measured resonance spectrum on a fine grid in the parameter plane. After applying a purely imaginary diagonal shift to the Hamiltonian, its eigenvalues are either real or complex conjugate on a curve, which passes through the EP. An appropriate basis choice reveals its PT symmetry. Spontaneous symmetry breaking occurs at the EP.

  16. Synthesis ofN-(2-chloro-5-methylthiophenyl)-N'-(3-methyl-thiophenyl)-N'-[3H3]methylguanidine, l brace [3H3]CNS-5161 r brace

    SciTech Connect

    Gibbs, Andrew R.; Morimoto, Hiromi; VanBrocklin, Henry F.; Williams, Philip G.; Biegon, Anat

    2001-09-28

    The preparation of the title compound, [{sup 3}H{sub 3}]CNS-5161, was accomplished in three steps starting with the production of [{sup 3}H{sub 3}]iodomethane (CT{sub 3}I). The intermediate N-[{sup 3}H{sub 3}]methyl-3-(thiomethylphenyl)cyanamide was prepared in 77% yield by the addition of CT{sub 3}I to 3-(thiomethylphenyl)cyanamide, previously treated with sodium hydride. Reaction of this tritiated intermediate with 2-chloro-5-thiomethylaniline hydrochloride formed the guanidine compound [{sup 3}H{sub 3}]CNS-5161. Purification by HPLC gave the desired labeled product in an overall yield of 9% with greater than 96% radiochemical purity and a final specific activity of 66 Ci mmol{sup -1}.

  17. Nqrs Data for C3H12INO7 [C3H7NO2·HIO3·2(H2O)] (Subst. No. 0646)

    NASA Astrophysics Data System (ADS)

    Chihara, H.; Nakamura, N.

    This document is part of Subvolume A `Substances Containing Ag … C10H15' of Volume 48 `Nuclear Quadrupole Resonance Spectroscopy Data' of Landolt-Börnstein - Group III `Condensed Matter'. It contains an extract of Section `3.2 Data tables' of the Chapter `3 Nuclear quadrupole resonance data' providing the NQRS data for C3H12INO7 [C3H7NO2·HIO3·2(H2O)] (Subst. No. 0646)

  18. Functional Symmetry of Endomembranes

    PubMed Central

    2007-01-01

    In higher eukaryotic cells pleiomorphic compartments composed of vacuoles, tubules and vesicles move from the endoplasmic reticulum (ER) and the plasma membrane to the cell center, operating in early biosynthetic trafficking and endocytosis, respectively. Besides transporting cargo to the Golgi apparatus and lysosomes, a major task of these compartments is to promote extensive membrane recycling. The endocytic membrane system is traditionally divided into early (sorting) endosomes, late endosomes and the endocytic recycling compartment (ERC). Recent studies on the intermediate compartment (IC) between the ER and the Golgi apparatus suggest that it also consists of peripheral (“early”) and centralized (“late”) structures, as well as a third component, designated here as the biosynthetic recycling compartment (BRC). We propose that the ERC and the BRC exist as long-lived “mirror compartments” at the cell center that also share the ability to expand and become mobilized during cell activation. These considerations emphasize the functional symmetry of endomembrane compartments, which provides a basis for the membrane rearrangements taking place during cell division, polarization, and differentiation. PMID:17267686

  19. Symmetry algebras of linear differential equations

    NASA Astrophysics Data System (ADS)

    Shapovalov, A. V.; Shirokov, I. V.

    1992-07-01

    The local symmetries of linear differential equations are investigated by means of proven theorems on the structure of the algebra of local symmetries of translationally and dilatationally invariant differential equations. For a nonparabolic second-order equation, the absence of nontrivial nonlinear local symmetries is proved. This means that the local symmetries reduce to the Lie algebra of linear differential symmetry operators. For the Laplace—Beltrami equation, all local symmetries reduce to the enveloping algebra of the algebra of the conformal group.

  20. Changes of the striatal /sup 3/H-spiperone binding 3 - 6 weeks after nigrostriatal denervation and after two years

    SciTech Connect

    Guerin, B.; Silice, C.; Mouchet, P.; Feuerstein, C.; Demenge, P.

    1985-09-09

    A complete unilateral lesion of the nigrostriatal pathway by 6-hydroxydopamine injection in the substantia nigra induced a drastic increase in striatal dopaminergic binding sites labelled by /sup 3/H-spiperone, 30 days after the lesion. This increase (75% over controls) was time restricted: it was only 39% and 34% over control values at respectively 25 and 35 days after the lesion. Furthermore, 45 days after the destruction of the substantia nigra, the density of labelled sites returned close to the homolateral control values, but remained higher than the contralateral ones, according to the right-left difference found in control animals. Quite later (2 years after the lesion), there was a decrease in the density of labelled sites as compared to the respective homolateral control levels. However, such binding sites tend to remain higher in the striatum of the lesioned side than in the striatum of the intact one, although such a difference was not statistically significant, being very close the right-left asymmetry observed in control animals. Contrary to previous results with /sup 3/H-Haloperidol, the apparent dissociation constant did not vary significantly, whatever the considered delay after the lesion. These results are discussed in the light of previous results obtained by others and by the authors. 28 references, 3 figures, 1 table.

  1. Identification and characterization of (/sup 3/H)-rauwolscine binding to alpha2-adrenoceptors in the canine saphenous vein

    SciTech Connect

    Gout, B.

    1988-01-01

    The biochemical exploration of the alpha2-adrenergic receptors was investigated in the canine saphenous vein using the highly selective alpha2-adrenergic antagonist rauwolscine as a tritiated ligand. Following an enzymatic digestive pretreatment, the authors isolated a purified smooth muscle cell membranes fraction from saphenous veins in quantity sufficient to permit them to study the venous alpha2-adrenoreceptor content. The binding of tritiated rauwolscine was rapid, specific, saturable and reversible. The presence of high affinity sites with a density of binding Bmax of 125.2 /+ -/ 43.1 fmol/mg protein was demonstrated on a unique class of non interacting sites. The kinetically derived Kd was 1.28 nM, in good agreement with the value obtained from saturation isotherms. The pharmacological profile of these sites was assessed by the comparison of the potency of alpha-adrenergic agonists and antagonists to inhibit 1 nM (/sup 3/H)-rauwolscine. Their efficacy was respectively: rauwolscine > phentolamine > RX 781094 > clonidine >> prazosin > (-)-phenylephrine > (-)-noradrenaline. The results showed that (/sup 3/H)-rauwolscine bound specifically to sites in their membranal preparation, which had the pharmacological characteristics of the alpha2-adrenoceptors. The correlation between biochemical and pharmacological data revealed the usefulness of binding methods in the further study of adrenergic mechanisms in the canine saphenous vein.

  2. Dynamical signatures of molecular symmetries in nonequilibrium quantum transport.

    PubMed

    Thingna, Juzar; Manzano, Daniel; Cao, Jianshu

    2016-06-17

    Symmetries play a crucial role in ubiquitous systems found in Nature. In this work, we propose an elegant approach to detect symmetries by measuring quantum currents. Our detection scheme relies on initiating the system in an anti-symmetric initial condition, with respect to the symmetric sites, and using a probe that acts like a local noise. Depending on the position of the probe the currents exhibit unique signatures such as a quasi-stationary plateau indicating the presence of metastability and multi-exponential decays in case of multiple symmetries. The signatures are sensitive to the characteristics of the probe and vanish completely when the timescale of the coherent system dynamics is much longer than the timescale of the probe. These results are demonstrated using a 4-site model and an archetypal example of the para-benzene ring and are shown to be robust under a weak disorder.

  3. Dynamical signatures of molecular symmetries in nonequilibrium quantum transport

    NASA Astrophysics Data System (ADS)

    Thingna, Juzar; Manzano, Daniel; Cao, Jianshu

    2016-06-01

    Symmetries play a crucial role in ubiquitous systems found in Nature. In this work, we propose an elegant approach to detect symmetries by measuring quantum currents. Our detection scheme relies on initiating the system in an anti-symmetric initial condition, with respect to the symmetric sites, and using a probe that acts like a local noise. Depending on the position of the probe the currents exhibit unique signatures such as a quasi-stationary plateau indicating the presence of metastability and multi-exponential decays in case of multiple symmetries. The signatures are sensitive to the characteristics of the probe and vanish completely when the timescale of the coherent system dynamics is much longer than the timescale of the probe. These results are demonstrated using a 4-site model and an archetypal example of the para-benzene ring and are shown to be robust under a weak disorder.

  4. Dynamical signatures of molecular symmetries in nonequilibrium quantum transport

    PubMed Central

    Thingna, Juzar; Manzano, Daniel; Cao, Jianshu

    2016-01-01

    Symmetries play a crucial role in ubiquitous systems found in Nature. In this work, we propose an elegant approach to detect symmetries by measuring quantum currents. Our detection scheme relies on initiating the system in an anti-symmetric initial condition, with respect to the symmetric sites, and using a probe that acts like a local noise. Depending on the position of the probe the currents exhibit unique signatures such as a quasi-stationary plateau indicating the presence of metastability and multi-exponential decays in case of multiple symmetries. The signatures are sensitive to the characteristics of the probe and vanish completely when the timescale of the coherent system dynamics is much longer than the timescale of the probe. These results are demonstrated using a 4-site model and an archetypal example of the para-benzene ring and are shown to be robust under a weak disorder. PMID:27311717

  5. Electroweak Symmetry Breaking: With Dynamics

    SciTech Connect

    Chivukula, R. Sekhar

    2005-03-22

    In this note I provide a brief description of models of dynamical electroweak symmetry breaking, including walking technicolor, top-color assisted technicolor, the top-quark seesaw model, and little higgs theories.

  6. Classification of spacetimes with symmetry

    NASA Astrophysics Data System (ADS)

    Hicks, Jesse W.

    Spacetimes with symmetry play a critical role in Einstein's Theory of General Relativity. Missing from the literature is a correct, usable, and computer accessible classification of such spacetimes. This dissertation fills this gap; specifically, we. i) give a new and different approach to the classification of spacetimes with symmetry using modern methods and tools such as the Schmidt method and computer algebra systems, resulting in ninety-two spacetimes; ii) create digital databases of the classification for easy access and use for researchers; iii) create software to classify any spacetime metric with symmetry against the new database; iv) compare results of our classification with those of Petrov and find that Petrov missed six cases and incorrectly normalized a significant number of metrics; v) classify spacetimes with symmetry in the book Exact Solutions to Einstein's Field Equations Second Edition by Stephani, Kramer, Macallum, Hoenselaers, and Herlt and in Komrakov's paper Einstein-Maxwell equation on four-dimensional homogeneous spaces using the new software.

  7. Symmetries from the solution manifold

    NASA Astrophysics Data System (ADS)

    Aldaya, Víctor; Guerrero, Julio; Lopez-Ruiz, Francisco F.; Cossío, Francisco

    2015-07-01

    We face a revision of the role of symmetries of a physical system aiming at characterizing the corresponding Solution Manifold (SM) by means of Noether invariants as a preliminary step towards a proper, non-canonical, quantization. To this end, "point symmetries" of the Lagrangian are generally not enough, and we must resort to the more general concept of contact symmetries. They are defined in terms of the Poincaré-Cartan form, which allows us, in turn, to find the symplectic structure on the SM, through some sort of Hamilton-Jacobi (HJ) transformation. These basic symmetries are realized as Hamiltonian vector fields, associated with (coordinate) functions on the SM, lifted back to the Evolution Manifold through the inverse of this HJ mapping, that constitutes an inverse of the Noether Theorem. The specific examples of a particle moving on S3, at the mechanical level, and nonlinear SU(2)-sigma model in field theory are sketched.

  8. Partial Dynamical Symmetry in Molecules

    NASA Astrophysics Data System (ADS)

    Ping, Jia-Lun; Chen, Jin-Quan

    1997-03-01

    It is shown that any Hamiltonian involving only one- and two-bond interactions for a molecule withnbonds and having a point groupPas its symmetry group may have theSn⊃Ppartial dynamical symmetry, i.e., the Hamiltonian can be solved analytically for a part of the states, called the unique states. For example, theXY6molecule has theS6⊃Ohpartial dynamical symmetry. The model of Iachello and Oss forncoupled anharmonic oscillators is revisited in terms of the partial dynamical symmetry. The energies are obtained analytically for the nine unique levels of theXY6molecule and the structures of the eigenstates are disclosed for the first time, while for non-unique states they are obtained by diagonalizing the Hamiltonian in theS6⊃Ohsymmetry adapted basis with greatly reduced dimension.

  9. Modulation of [3H]diazepam binding in rat cortical membranes by GABAA agonists.

    PubMed

    Wong, E H; Iversen, L L

    1985-04-01

    GABAA receptor agonists modulate [3H]diazepam binding in rat cortical membranes with different efficacies. At 23 degrees C, the relative potencies for enhancement of [3H]diazepam binding by agonists parallel their potencies in inhibiting [3H]gamma-aminobutyric acid [( 3H]GABA) binding. The agonist concentrations needed for enhancement of [3H]diazepam binding are up to 35 times higher than for [3H]GABA binding and correspond closely to the concentrations required for displacement of [3H]bicuculline methochloride (BMC) binding. The maximum enhancement of [3H]diazepam varied among agonists: muscimol = GABA greater than isoguvacine greater than 3-aminopropane sulphonic acid (3APS) = imidazoleacetic acid (IAA) greater than 4,5,6,7-tetrahydroisoxazolo (4,5,6)-pyridin-3-ol (THIP) = taurine greater than piperidine 4-sulphonic acid (P4S). At 37 degrees C, the potencies of agonists remained unchanged, but isoguvacine, 3 APS, and THIP acquired efficacies similar to GABA, whereas IAA, taurine, and P4S maintained their partial agonist profiles. At both temperatures the agonist-induced enhancement of [3H]diazepam binding was reversible by bicuculline methobromide and by the steroid GABA antagonist RU 5135. These results stress the importance of studying receptor-receptor interaction under near-physiological conditions and offer an in vitro assay that may predict the agonist status of putative GABA receptor ligands.

  10. Broken Symmetries and Magnetic Dynamos

    NASA Technical Reports Server (NTRS)

    Shebalin, John V.

    2007-01-01

    Phase space symmetries inherent in the statistical theory of ideal magnetohydrodynamic (MHD) turbulence are known to be broken dynamically to produce large-scale coherent magnetic structure. Here, results of a numerical study of decaying MHD turbulence are presented that show large-scale coherent structure also arises and persists in the presence of dissipation. Dynamically broken symmetries in MHD turbulence may thus play a fundamental role in the dynamo process.

  11. Possible violations of spacetime symmetries

    NASA Astrophysics Data System (ADS)

    Urrutia, Luis

    2016-10-01

    The identification of symmetries has played a fundamental role in our understanding of physical phenomena. Nevertheless, in most cases such symmetries constitute only a zeroth-order approximation and they need to be broken so that the predictions of the theory are consistent with experimental observation. In particular, the almost sacred CPT and Lorentz symmetries, which are certainly part of the fundamental ideas of modern physics, need to be probed experimentally. Recently, such efforts have been intensified because different theoretical approaches aiming to understand the microstructure of space-time suggest the possibility that such symmetries could present minute violations. Up to now, and with increasing experimental sensitivities, no signs of violation have been found. Nevertheless, we observe that even the persistence of such negative results will have a profound impact. On one hand, they will provide those symmetries with a firm experimental basis. On the other, they will set stringent experimental bounds to be compared with the possible emergence of such violations in quantum gravity models based upon a discrete structure of space. We present a very general perspective of the research on Lorentz symmetry breaking, together with a review of a few specific topics.

  12. Displacement of /sup 3/H-EKC binding by opioids in rat kidney: A correlate to diuretic activity

    SciTech Connect

    Slizgi, G.R.; Ludens, J.H.

    1985-06-10

    Multiple opioid binding sites have been documented in brain tissue. In this study the authors report on the presence of binding sites for that opioid ethylketocyclazocine (EKC) in a membrane fraction of rat kidney. Binding appeared to be selective in the opioids varied markedly in their capacities to displace /sup 3/ -EKC. Correlating with the capacity of an opioid to displace /sup 3/H-EKC was the ability to produce diuresis. Although the studies cannot assign a particular physiological or pharmacological role for the renal EKC binding sites, binding studies of this nature may, nonetheless, be a means by which diuretic activity of opioids can be predicted. 15 references, 2 figures, 1 table.

  13. How does symmetry impact the flexibility of proteins?

    PubMed

    Schulze, Bernd; Sljoka, Adnan; Whiteley, Walter

    2014-02-13

    It is well known that (i) the flexibility and rigidity of proteins are central to their function, (ii) a number of oligomers with several copies of individual protein chains assemble with symmetry in the native state and (iii) added symmetry sometimes leads to added flexibility in structures. We observe that the most common symmetry classes of protein oligomers are also the symmetry classes that lead to increased flexibility in certain three-dimensional structures-and investigate the possible significance of this coincidence. This builds on the well-developed theory of generic rigidity of body-bar frameworks, which permits an analysis of the rigidity and flexibility of molecular structures such as proteins via fast combinatorial algorithms. In particular, we outline some very simple counting rules and possible algorithmic extensions that allow us to predict continuous symmetry-preserving motions in body-bar frameworks that possess non-trivial point-group symmetry. For simplicity, we focus on dimers, which typically assemble with twofold rotational axes, and often have allosteric function that requires motions to link distant sites on the two protein chains.

  14. How does symmetry impact the flexibility of proteins?

    PubMed Central

    Schulze, Bernd; Sljoka, Adnan; Whiteley, Walter

    2014-01-01

    It is well known that (i) the flexibility and rigidity of proteins are central to their function, (ii) a number of oligomers with several copies of individual protein chains assemble with symmetry in the native state and (iii) added symmetry sometimes leads to added flexibility in structures. We observe that the most common symmetry classes of protein oligomers are also the symmetry classes that lead to increased flexibility in certain three-dimensional structures—and investigate the possible significance of this coincidence. This builds on the well-developed theory of generic rigidity of body–bar frameworks, which permits an analysis of the rigidity and flexibility of molecular structures such as proteins via fast combinatorial algorithms. In particular, we outline some very simple counting rules and possible algorithmic extensions that allow us to predict continuous symmetry-preserving motions in body–bar frameworks that possess non-trivial point-group symmetry. For simplicity, we focus on dimers, which typically assemble with twofold rotational axes, and often have allosteric function that requires motions to link distant sites on the two protein chains. PMID:24379431

  15. Metabolism of myo-[2-3H]Inositol and scyllo-[R-3H]Inositol in Ripening Wheat Kernels 1

    PubMed Central

    Sasaki, Ken; Loewus, Frank A.

    1980-01-01

    Injection of myo-[2-3H]inositol or scyllo-[R-3H]inositol into the peduncular cavity of wheat stalks about 2 to 4 weeks postanthesis led to rapid translocation into the spike and accumulation of label in developing kernels, especially the bran fraction. With myo-[2-3H]inositol, about 50 to 60% of the label was incorporated into high molecular weight cell wall substance in the region of the injection. That portion translocated to the kernels was utilized primarily for cell wall polysaccharide formation and phytate biosynthesis. A small amount was recovered as free myo-inositol and galactinol. When scyllo-[R-3H]inositol was supplied, most of the label was translocated into the developing kernels where it accumulated as free scyllo-inositol and O-α-d-galactopyranosyl-scyllo-inositol in approximately equal amount. None of the label from scyllo-[R-3H]inositol was utilized for either phytate biosynthesis or cell wall polysaccharide formation. PMID:16661513

  16. Amphetamine-enhanced accumulation of ( sup 3 H)-spiperone in mouse corpus striatum in vivo: Modification by other drugs

    SciTech Connect

    Dorris, R.L. )

    1989-01-01

    Other investigators have reported that amphetamine administered to rodents results in an increase in the in vivo accumulation of either the tritiated dopamine receptor ligand, spiperone or pimozide in the dopaminergic corpus striatum, (specific binding) while not altering that in the sparsely dopaminergically innervated cerebellum (non-specific binding). Experiments were undertaken to determine if the results could be replicated and if some other drugs would modify the effect. Male mice were injected with ({sup 3}H)-spiperone (20 {mu}Ci/Kg, 0.0003 mg/kg) s.c. and killed 2 hrs later for determination of radioactivity in corpus striatum and cerebellum. Amphetamine (20 mg/kg, i.p.) given 15 min before ({sup 3}H)-spiperone, increased accumulation in striatum but not cerebellum. The increase was inhibited by {alpha} - methyltyrosine ({alpha}-MT), haloperidol, reserpine or amantadine. It is suggested that the amphetamine-induced increase in accumulation of ({sup 3}H)-spiperone in corpus striatum (specific binding) depends on release of large amounts of dopamine, which then must be able to interact with the dopamine receptor. The antagonism of the effect by {alpha}-MT or reserpine can be explained by dopamine depletion, that of haloperidol by antagonism for binding at the receptor site. It is suggested that amantadine acts by a dual mechanism: (1) as a low efficacy agonist, it competes for binding to the receptor and (2) it has some ability to block dopamine release.

  17. Multiple benzodiazepine receptors in the ovine brain: ontogenesis, properties, and distribution of /sup 3/H-diazepam binding

    SciTech Connect

    Villiger, J.W.; Taylor, K.M.; Gluckman, P.D.

    1982-01-01

    Benzodiazepine receptors in the ovine frontal cortex were present at 56 days gestation and developed slowly until 96 days when the number increased rapidly, reaching adult levels by 120 days gestation. Scatchard analysis of 3H-diazepam specifically bound to cortical membranes suggested high (KD approximately equal to 2.0 nM) and low (KD approximately equal to 20.0 nM) affinity benzodiazepine receptors at all stages of development. Whereas the affinity of these receptors for 3H-diazepam did not alter during development, the number of both high and low affinity receptors increased significantly between 56 and 120 days gestation. The number of low affinity receptors were higher in late gestation and early neonatal life than in adulthood. The functional state of these receptors as determined by sensitivity to GABA did not alter during development. However, in the adult, nitrazepam, flunitrazepam, midazolam, and 1-methylisoguanosine were more potent in displacing 3H-diazepam at the low affinity than the high affinity receptor, whereas chlordiazepoxide and diazepam had greater potency at the high affinity binding site. Development of the benzodiazepine receptor in the majority of other brain regions studied occurred primarily after 68 days gestation, as was the case in frontal cortex. In contrast, hindbrain and midbrain benzodiazepine receptors had reached adult levels by 68 days gestation.

  18. Structures of NADH and CH[subscript 3]-H[subscript 4] Folate Complexes of Escherichia coli Methylenetetrahydrofolate Reductase Reveal a Spartan Strategy for a Ping-Pong Reaction

    SciTech Connect

    Pejchal, Robert; Sargeant, Ryan; Ludwig, Martha L.

    2010-03-08

    Methylenetetrahydrofolate reductases (MTHFRs; EC 1.7.99.5) catalyze the NAD(P)H-dependent reduction of 5,10-methylenetetrahydrofolate (CH{sub 2}-H{sub 4}folate) to 5-methyltetrahydrofolate (CH{sub 3}-H{sub 4}folate) using flavin adenine dinucleotide (FAD) as a cofactor. The initial X-ray structure of Escherichia coli MTHFR revealed that this 33-kDa polypeptide is a ({beta}{alpha}){sub 8} barrel that aggregates to form an unusual tetramer with only 2-fold symmetry. Structures of reduced enzyme complexed with NADH and of oxidized Glu28Gln enzyme complexed with CH{sub 3}-H{sub 4}folate have now been determined at resolutions of 1.95 and 1.85 {angstrom}, respectively. The NADH complex reveals a rare mode of dinucleotide binding; NADH adopts a hairpin conformation and is sandwiched between a conserved phenylalanine, Phe223, and the isoalloxazine ring of FAD. The nicotinamide of the bound pyridine nucleotide is stacked against the si face of the flavin ring with C4 adjoining the N5 of FAD, implying that this structure models a complex that is competent for hydride transfer. In the complex with CH{sub 3}-H{sub 4}folate, the pterin ring is also stacked against FAD in an orientation that is favorable for hydride transfer. Thus, the binding sites for the two substrates overlap, as expected for many enzymes that catalyze ping-pong reactions, and several invariant residues interact with both folate and pyridine nucleotide substrates. Comparisons of liganded and substrate-free structures reveal multiple conformations for the loops {beta}2-{alpha}2 (L2), {beta}3-{alpha}3 (L3), and {beta}4-{alpha}4 (L4) and suggest that motions of these loops facilitate the ping-pong reaction. In particular, the L4 loop adopts a 'closed' conformation that allows Asp120 to hydrogen bond to the pterin ring in the folate complex but must move to an 'open' conformation to allow NADH to bind.

  19. Temperature and Ca2+ dependence of [3H]ryanodine binding in the burbot (Lota lota L.) heart.

    PubMed

    Vornanen, Matti

    2006-02-01

    Opening and closing of the cardiac ryanodine (Ry) receptor (RyR) are coordinated by the free intracellular Ca2+ concentration, thus making the Ca2+ binding properties of the RyR important for excitation-contraction coupling. Unlike mammalian cardiac RyRs, which lose their normal function at low temperatures, RyRs of ectothermic vertebrates remain operative at 2-4 degrees C, as indicated by Ry sensitivity of contractile force. To investigate the mechanisms of low temperature adaptation of ectothermic RyRs, we compared Ca2+-dependent kinetics of [3H]ryanodine binding in cardiac preparations of a fish (burbot, Lota lota) and a mammal (rat). The number of ventricular [3H]ryanodine binding sites determined at 20 degrees C was 1.54 times higher in rat than burbot heart (0.401 +/- 0.039 and 0.264 +/- 0.019 pmol/mg protein, respectively) (P < 0.02), while the binding affinity (Kd) for [3H]ryanodine was similar (3.38 +/- 0.63 and 4.38 +/- 1.14 nM for rat and burbot, respectively) (P = 0.47). The high-affinity [3H]ryanodine binding to burbot and rat cardiac preparations was tightly coordinated by the free Ca2+ concentration at both 20 degrees C and 2 degrees C and did not differ between the two species. Half-maximal [3H]ryanodine binding occurred at 0.191 +/- 0.027 microM and 0.164 +/- 0.034 microM Ca2+ for rat and at 0.212 +/- 0.035 microM and 0.188 +/- 0.039 microM Ca2+ for burbot (P = 0.65), at 2 degrees C and 20 degrees C, respectively. In two other fish species, rainbow trout (Oncorhynchus mykiss) and crucian carp (Carassius carassius), the Ca2+-binding affinity at 20 degrees C was 4.4 and 5.9 times lower, respectively, than in the burbot. At 20 degrees C, the rate of [3H]ryanodine binding to the high-affinity binding site was similar in rat and burbot but was drastically slowed in rat at 2 degrees C. At 2 degrees C, [3H]ryanodine failed to dissociate from rat cardiac RyRs, and at 10 degrees C and 20 degrees C, the rate of dissociation was two to three times slower in

  20. Symmetry in polarimetric remote sensing

    NASA Technical Reports Server (NTRS)

    Nghiem, S. V.; Yueh, S. H.; Kwok, R.

    1993-01-01

    Relationships among polarimetric backscattering coefficients are derived from the viewpoint of symmetry groups. For both reciprocal and non-reciprocal media, symmetry encountered in remote sensing due to reflection, rotation, azimuthal, and centrical symmetry groups is considered. The derived properties are general and valid to all scattering mechanisms, including volume and surface scatterings and their interactions, in a given symmetrical configuration. The scattering coefficients calculated from theoretical models for layer random media and rough surfaces are shown to obey the symmetry relations. Use of symmetry properties in remote sensing of structural and environmental responses of scattering media is also discussed. Orientations of spheroidal scatterers described by spherical, uniform, planophile, plagiothile, erectophile, and extremophile distributions are considered to derive their polarimetric backscattering characteristics. These distributions can be identified from the observed scattering coefficients by comparison with theoretical symmetry calculations. A new parameter is then defined to study scattering structures in geophysical media. Observations from polarimetric data acquired by the Jet Propulsion Laboratory airborne synthetic aperture radar over forests, sea ice, and sea surface are presented. Experimental evidences of the symmetry relationships are shown and their use in polarimetric remote sensing is illustrated. For forests, the coniferous forest in Mt. Shasta area (California) and mixed forest near Presque Isle (Maine) exhibit characteristics of the centrical symmetry at C-band. For sea ice in the Beaufort Sea, multi-year sea ice has a cross-polarized ratio e close to e(sub 0), calculated from symmetry, due to the randomness in the scattering structure. First-year sea ice has e much smaller than e(sub 0) due to the preferential alignment of the columnar structure of the ice. From polarimetric data of a sea surface in the Bering Sea, it is

  1. C(sp3)-H bond hydroxylation catalyzed by myoglobin reconstituted with manganese porphycene.

    PubMed

    Oohora, Koji; Kihira, Yushi; Mizohata, Eiichi; Inoue, Tsuyoshi; Hayashi, Takashi

    2013-11-20

    Myoglobin reconstituted with manganese porphycene was prepared in an effort to generate a new biocatalyst and was characterized by spectroscopic techniques. The X-ray crystal structure of the reconstituted protein reveals that the artificial cofactor is located in the intrinsic heme-binding site with weak ligation by His93. Interestingly, the reconstituted protein catalyzes the H2O2-dependent hydroxylation of ethylbenzene to yield 1-phenylethanol as a single product with a turnover number of 13 at 25 °C and pH 8.5. Native myoglobin and other modified myoglobins do not catalyze C-H hydroxylation of alkanes. Isotope effect experiments yield KIE values of 2.4 and 6.1 for ethylbenzene and toluene, respectively. Kinetic data, log kobs versus BDE(C(sp(3))-H) for ethylbenzene, toluene, and cyclohexane, indicate a linear relationship with a negative slope. These findings clearly indicate that the reaction occurs via a rate-determining step that involves hydrogen-atom abstraction by a Mn(O) species and a subsequent rebound hydroxylation process which is similar to the reaction mechanism of cytochrome P450.

  2. Spinal cord distribution of sup 3 H-morphine after intrathecal administration: Relationship to analgesia

    SciTech Connect

    Nishio, Y.; Sinatra, R.S.; Kitahata, L.M.; Collins, J.G. )

    1989-09-01

    The distribution of intrathecally administered {sup 3}H-morphine was examined by light microscopic autoradiography in rat spinal cord and temporal changes in silver grain localization were compared with results obtained from simultaneous measurements of analgesia. After tissue processing, radio-activity was found to have penetrated in superficial as well as in deeper layers (Rexed lamina V, VII, and X) of rat spinal cord within minutes after application. Silver grain density reached maximal values at 30 min in every region of cord studied. Radioactivity decreased rapidly between 30 min and 2 hr and then more slowly over the next 24 hr. In rats tested for responses to a thermal stimulus (tail flick test), intrathecal administration of morphine (5 and 15 micrograms) resulted in significant dose dependent analgesia that peaked at 30 min and lasted up to 5 hr (P less than 0.5). There was a close relationship between analgesia and spinal cord silver grain density during the first 4 hr of the study. It is postulated that the onset of spinal morphine analgesia depends on appearance of molecules at sites of action followed by the activation of anti-nociceptive mechanisms.

  3. Distribution of /sup 3/H-morphine following lumbar subarachnoid injection in unanesthetized rabbits

    SciTech Connect

    Wang, B.C.; Hiller, J.M.; Simon, E.J.; Hillman, D.E.; Rosenberg, C.; Turndorf, H.

    1989-05-01

    Morphine sulfate (40-100 micrograms) and /sup 3/H-morphine (125-200 pmol) were injected into the lumbar subarachnoid space of 18 unanesthetized rabbits through a surgically implanted catheter. Radioactivity remaining in the spinal cord 2, 4, 6, and 12 h later revealed recovery (mean +/- SEM) of 45 +/- 5.6% (n = 3), 30.5 +/- 14.1% (n = 4), 11.23 +/- 4.4% (n = 3), and 3.7 +/- 1.1% (n = 3), respectively, of the injected radioactivity. Tritiated morphine was found to be predominantly centered around the injection site, with limited rostral and caudal spread in the cord. No significant radioactivity was detected in plasma or cerebrospinal fluid (CSF) samples from the cisterna magna taken at 5, 15, 30, min and 1, 2, 4, 6, 12, and 24 h after receiving radioactive labeled drug (with the exception of that in one rabbit). Of the injected radioactivity, 75% was recovered in the urine in 12 h. These results suggest that the persistence of morphine in the spinal cord could account for its prolonged analgesic effect following intrathecal administration.

  4. Effect of cannabinoids on the binding of /sup 3/H-(3-MeHis/sup 2/)TRH to rat brain membranes

    SciTech Connect

    Matwyshyn, G.A.; Das, S.; Bhargava, H.N.

    1986-03-05

    Cannabinoids, particularly ..delta../sup 9/-THC is known to affect thyroid function. The effect of naturally occurring and synthetic cannabinoids on brain TRH receptors labeled with /sup 3/H-(3-MeHis/sup 2/)TRH(MeTRH) was determined. /sup 3/H-MeTRH bound to brain membranes at a single high affinity binding sites with a B/sub max/ of 48 +/- 2 fmol/mg protein and K/sub d/ of 4.2 +/- 0.4 nM. At 2 nM concentration the amount of /sup 3/H-MeTRH bound specifically was 10.9 +/- 0.6 fmol/mg protein. ..delta.. /sup 9/-THC (10/sup -7/ to 10/sup -3/ M) stimulated the binding of /sup 3/H-MeTRH with maximal stimulation of 60% at 10/sup -4/M concentration. Cannabinol (10/sup -6/-/sup -4/M) also enhanced the binding of /sup 3/H-MeTRH with maximal (58%) stimulation occurring at 10/sup -5/M concentration. Cannabidiol, on the other hand, had no effect on the binding of /sup 3/H-MeTRH up to 10/sup -5/M concentration. However, at 10/sup -4/M concentration of cannabidiol, the binding of /sup 3/H-MeTRH was decreased by 65%. The water soluble synthetic cannabinoids, naboctate, menabitan and SP 111 A inhibited the binding of /sup 3/H-MeTRH only at 10/sup -4/ or 10/sup -3/M concentration. These results suggest differential interaction of cannabinoids with brain TRH receptors.

  5. Temperature-dependent modulation of (/sup 3/H)nitrendipine binding by the calcium channel antagonists verapamil and diltiazem in rat brain synaptosomes

    SciTech Connect

    Boles, R.G.; Yamamura, H.I.; Schoemaker, H.; Roeske, W.R.

    1984-05-01

    Binding of the dihydropyridine calcium channel antagonist (/sup 3/H)nitrendipine to an intact rat brain mitochondrial-synaptosomal fraction (P/sub 2/) was specific, saturable, temperature-dependent and of high affinity (K/sub d/ . 115-467 pM). The effects of the calcium channel antagonists verapamil and diltiazem on (/sup 3/H)nitrendipine binding and their temperature dependence were investigated. At 0 and 25 degrees C, verapamil inhibited (/sup 3/H)nitrendipine binding incompletely in a manner consistent with an allosteric modulation and nearly independent of the incubation temperature. The effects of diltiazem, however, were found to be highly temperature-dependent. At 25 and 37 degrees C, 10 microM diltiazem enhanced (/sup 3/H)nitrendipine binding to values of 140 and 200% of control, respectively. At 0 degrees C, 10 microM diltiazem inhibited (/sup 3/H)nitrendipine binding to a value of 68% of control. Analysis of saturation isotherms at steady state demonstrated that at all temperatures studied the effects of verapamil and diltiazem on (/sup 3/H)nitrendipine binding were due to alterations in the ligand dissociation constant (K/sub d/). At 25 degrees C, these alterations were mediated by changes in the rate of ligand-receptor complex dissociation. Competition studies of verapamil and diltiazem at 25 and 0 degrees C indicate that the effects of these two drugs on (/sup 3/H)nitrendipine binding are mutually exclusive. We conclude that the binding of (/sup 3/H)nitrendipine is allosterically modulated by spacially related binding sites for verapamil and diltiazem.

  6. Behavior of substances labeled with /sup 3/H-proline and /sup 3/H-fucose in the cellular processes of odontoblasts and ameloblasts

    SciTech Connect

    Warshawsky, H.; Josephsen, K.

    1981-05-01

    Odontoblasts are cells with single cytoplasmic processes that grow longer as more dentin is elaborated. Ameloblasts also have single processes and it has been postulated that they too grow longer as more enamel is made. Support for this hypothesis was obtained using rat incisors to investigate the behavior of substances labeled with /sup 3/H-proline and /sup 3/H-fucose. A comparison was made between odontoblasts, which have processes known to grow and remain within the dentin, and the ameloblasts whose Tomes' processes are hypothesized to grow and leave remnants in the completed enamel. With /sup 3/H-proline, the odontoblast bodies are labeled at the early time intervals. With /sup 3/H-fucose, the cell bodies are labeled at the early intervals and the newly formed glycoproteins are deposited into the predentin. Almost immediately, these are progressively added to the dentin at the calcification front. With time a gradient of labeling extends from the unlabeled dentin toward the odontoblast bodies. Unlike the behavior of labeled proteins, by 1 and 2 days labeled glycoproteins appear along the entire length of the odontoblast processes. In the enamel, no Tomes' processes are present during maturation. With /sup 3/H-proline, reactions are adjacent to the cells and diffuse toward, but do not reach the dentino-enamel junction by 1 and 2 days. With /sup 3/H-fucose, reactions appear over the enamel near the cells. By 1 and 2 days no diffusive pattern is seen, but grains are concentrated near the dentino-enamel junction, in a region containing holes known to be the beginning of Tomes' processes. Since odontoblast glycoproteins migrate along odontoblast processes, it was postulated that cytoplasmic remnants were present in enamel along which ameloblast glycoproteins could also migrate to reach the holes at the dentino-enamel junction.

  7. Comparison of /sup 3/H-galactose and /sup 3/H-glucose as precursors of hepatic glycogen in control-fed rats

    SciTech Connect

    Michaels, J.E.; Garfield, S.A.; Hung, J.T.; Cardell, R.R. Jr.

    1989-05-01

    Labeling of hepatic glycogen derived from 3H-galactose and 3H-glucose was compared shortly after intravenous injection in control-fed rats. The rats were allowed to accumulate 5-8% glycogen prior to receiving label. Fifteen minutes to 2 hours after labeling, liver was excised and processed for routine light (LM) and electron microscopic (EM) radioautography (RAG) or biochemical analysis. After injection of 3H-galactose, LM-RAGs revealed that the percentage of heavily labeled hepatocytes increased from 37% after 15 minutes to 68% after 1 hour but showed no further increase after 2 hours. alpha-Amylase treatment removed most glycogen and incorporated label; thus few silver grains were observed, indicating little incorporation of label except into glycogen. EM-RAGs demonstrated that most label occurred where glycogen was located. Biochemical analysis showed initially a high blood level of label that rapidly plateaued at a reduced level by 5 minutes. Concomitantly, glycogen labeling determined by liquid scintillation counting reflected the increases observed in the RAGs. After injection of 3H-glucose, LM-RAGs revealed that only 12% of the hepatocytes were heavily labeled at 1 hour and 20% at 2 hours. In tissue treated with alpha-amylase, glycogen was depleted and label was close to background level at each interval observed. EM-RAGs showed most grains associated with glycogen deposits. Biochemically, blood levels of label persisted at a high level for 30 minutes and tissue levels increased slowly over the 2-hour period. This study shows that incorporation from 3H-galactose was more rapid than incorporation of 3H-glucose; however, label derived from both carbohydrates appeared to be incorporated mainly into glycogen.

  8. Characterization of Samples from the 3H Evaporator System Including Effects of Recycle

    SciTech Connect

    Wilmarth, W.R.

    2001-05-15

    Analysis of several series of samples from the 3H Evaporator System have been completed. The goal of this work was to determine the effects of 3H operation including recycle of concentrated supernate from Tank 30H into the sludge layer of Tank 32H.

  9. Morphine enhances the release of /sup 3/H-purines from rat brain cerebral cortical prisms

    SciTech Connect

    Wu, P.H.; Phillis, J.W.; Yuen, H.

    1982-10-01

    In vitro experiments have shown that /sup 3/H-purines can be released from /sup 3/H-adenosine preloaded rat brain cortical prisms by a KCl-evoked depolarization. The KCl-evoked release of /sup 3/H-purines is dependent on the concentration of KCl present in the superfusate. At concentrations of 10(-7) approximately 10(-5)M morphine did not influence the basal release of /sup 3/H-purines from the prisms, although it enhanced the KCl-evoked release of /sup 3/H-purines. The enhancement of KCl-evoked /sup 3/H-purine release by morphine was concentration-dependent and was antagonized by naloxone, suggesting the involvement of opiate receptors. Uptake studies with rat brain cerebral cortical synaptosomes show that morphine is a very weak inhibitor of adenosine uptake. Comparisons with dipyridamole, a potent inhibitor of adenosine uptake, suggest that this low level of inhibition of the uptake did not contribute significantly to the release of /sup 3/H-purine by morphine seen in our experiments. It is therefore suggested that morphine enhances KCl-evoked /sup 3/H-purine release by an interaction with opiate receptors and that the resultant increase in extracellular purine (adenosine) levels may account for some of the actions of morphine.

  10. Nuclear accident-derived (3)H in river water of Fukushima Prefecture during 2011-2014.

    PubMed

    Ueda, Shinji; Hasegawa, Hidenao; Kakiuchi, Hideki; Ochiai, Shinya; Akata, Naofumi; Hisamatsu, Shun'ichi

    2015-08-01

    During 2011-2014, we measured (3)H concentrations in river water samples collected during base flow conditions and during several flood events from two small rivers in a mountainous area in Fukushima Prefecture, which received deposition of (137)Cs from the Fukushima Dai-ichi Nuclear Power Plant accident. (3)H concentrations above background levels were found in water samples collected during both base flow conditions and flood events in 2011. The (3)H concentrations during flood events were generally higher than those during base flow conditions. The (3)H concentrations in both rivers during base flow conditions and flood events decreased with time after the accident and reached almost background levels in 2013. We also measured (3)H concentrations in freshwater samples from 16 other rivers and one dam in eastern Fukushima Prefecture from 2012 to 2014 during base flow conditions. The measured (3)H concentrations were higher than the background level in 2012 and decreased with time. The (137)Cs inventory in the catchment area at each sampling point was estimated from air-borne monitoring results in the literature and compared with the (3)H concentrations. We found surprisingly good correlations between (137)Cs inventories in the catchment areas and (3)H concentrations in the water samples. Further studies will be necessary to clarify the reason for the good correlation.

  11. Elevated ZC3H15 increases HCC growth and predicts poor survival after surgical resection

    PubMed Central

    Li, Li-mei; Liu, Hui; Fu, Si-yuan; Yang, Yuan; Zhang, Jin; Yuan, Shen-xian; Wang, Ruo-yu; Yang, Yun; Gu, Fang-ming; Dong, Li-wei; Pan, Ze-ya; Zhou, Wei-ping

    2016-01-01

    Zinc finger CCCH-type containing 15 (ZC3H15), also known as DRG family regulatory protein 1 (DFRP1), is a highly conserved eukaryotic protein that associates with active translation machinery. The aim of our study was to explore the clinical relevance and intrinsic functions of ZC3H15 in hepatocellular carcinoma (HCC). We constructed a cohort with 261 tumor and matched normal tissues from HCC patients. ZC3H15 protein and mRNA levels were determined using immunohistochemistry, western blot analysis, and quantitative polymerase chain reaction. ZC3H15 was highly expressed in the majority of HCC cases, and high ZC3H15 levels were significantly associated with high serum a-fetoprotein (AFP) levels (>20 ng/mL) and vascular invasion. Kaplan-Meier and Cox regression data indicated that elevated ZC3H15 was an independent predictor for HCC-specific disease-free survival (hazards ratio [HR], 1.789; 95% confidence interval [95% CI], 1.298-2.466 [P=0.0004]) and overall survival (HR, 1.613; 95% CI, 1.120-2.322 [P=0.0101]). Interaction of ZC3H15 with TRAF2 increased activation of NFκB signaling. These results suggest ZC3H15 is an independent prognostic marker in HCC patients that is clinicopathologically associated with tumor invasion and serum AFP levels. PMID:27191988

  12. A new class of adenosine receptors in brain: Characterization by 2-chloro( sup 3 H)adenosine binding

    SciTech Connect

    Chin, Jerome Hsicheng.

    1988-01-01

    Considerable evidence has accumulated in recent years to support a role for adenosine as an important physiological modulator in many mammalian tissues. In brain, adenosine is a potent depressant of neuronal firing and synaptic transmission. The exact mechanisms by which adenosine analogs depress nerve cell activity in the brain are not clear. Despite considerable investigation, neither the A1 nor the A2 adenosine receptors associated with adenylate cyclase have been able to account adequately for the actions of adenosine in brain. It has been proposed that additional adenosine receptors, possibly linked to calcium channels, are present in the central nervous system and are responsible for the physiological actions of adenosine. In this thesis, evidence is provided for the existence of a novel class of adenosine receptors in rat brain. The methods used to identify this new class of receptors involved radioligand binding techniques which have been successfully employed to characterize the properties of many neurotransmitter and drug receptors. 2-Chloro({sup 3}H)adenosine (Cl({sup 3}H)Ado) was selected as the ligand for these experiments since is a water-soluble, metabolically-stable analog of adenosine and a potent depressant of synaptic transmission in brain. The results demonstrate the presence of a distinct class of 2-chloro({sup 3}H)adenosine binding sites in rat forebrain membranes with an apparent K{sub D} of about 10 {mu}M and a B{sub max} of about 60 pmol per mg of protein. Specific 2-chloro ({sup 3}H)adenosine binding is highly specific for adenosine agonists and antagonists. Inhibition of binding by adenosine agonists exhibits an order of potency 2-chloroadenosine > 5{prime}-N-ethylcarboxamide adenosine > ({minus})-N{sup 6}-(R-phenylisopropyl)adenosine, which differs from that of both A1 and A2 adenosine receptors.

  13. Volumetric Properties of the Mixture Propenenitrile C3H3N + C3H6O2 Methyl ethanoate (VMSD1511, LB4267_V)

    NASA Astrophysics Data System (ADS)

    Cibulka, I.; Fontaine, J.-C.; Sosnkowska-Kehiaian, K.; Kehiaian, H. V.

    This document is part of Subvolume C 'Binary Liquid Systems of Nonelectrolytes III' of Volume 26 'Heats of Mixing, Vapor-Liquid Equilibrium, and Volumetric Properties of Mixtures and Solutions' of Landolt-Börnstein Group IV 'Physical Chemistry'. It contains the Chapter 'Volumetric Properties of the Mixture Propenenitrile C3H3N + C3H6O2 Methyl ethanoate (VMSD1511, LB4267_V)' providing data from direct measurement of low-pressure thermodynamic speed of sound at variable mole fraction and constant temperature, in the single-phase region(s).

  14. Volumetric Properties of the Mixture Propenenitrile C3H3N + C3H6O2 Methyl ethanoate (VMSD1412, LB4273_V)

    NASA Astrophysics Data System (ADS)

    Cibulka, I.; Fontaine, J.-C.; Sosnkowska-Kehiaian, K.; Kehiaian, H. V.

    This document is part of Subvolume C 'Binary Liquid Systems of Nonelectrolytes III' of Volume 26 'Heats of Mixing, Vapor-Liquid Equilibrium, and Volumetric Properties of Mixtures and Solutions' of Landolt-Börnstein Group IV 'Physical Chemistry'. It contains the Chapter 'Volumetric Properties of the Mixture Propenenitrile C3H3N + C3H6O2 Methyl ethanoate (VMSD1412, LB4273_V)' providing data by calculation of isentropic compressibility from low-pressure density and thermodynamic speed of sound data at variable mole fraction and constant temperature, in the single-phase region(s).

  15. Volumetric Properties of the Mixture Propenenitrile C3H3N + C3H8O Propan-1-ol (VMSD1511, LB4926_V)

    NASA Astrophysics Data System (ADS)

    Cibulka, I.; Fontaine, J.-C.; Sosnkowska-Kehiaian, K.; Kehiaian, H. V.

    This document is part of Subvolume C 'Binary Liquid Systems of Nonelectrolytes III' of Volume 26 'Heats of Mixing, Vapor-Liquid Equilibrium, and Volumetric Properties of Mixtures and Solutions' of Landolt-Börnstein Group IV 'Physical Chemistry'. It contains the Chapter 'Volumetric Properties of the Mixture Propenenitrile C3H3N + C3H8O Propan-1-ol (VMSD1511, LB4926_V)' providing data from direct measurement of low-pressure thermodynamic speed of sound at variable mole fraction and constant temperature, in the single-phase region(s).

  16. A combined crossed beam and theoretical investigation of O(3P)+C3H3→C3H2+OH

    NASA Astrophysics Data System (ADS)

    Lee, Hohjai; Joo, Sun-Kyu; Kwon, Lee-Kyoung; Choi, Jong-Ho

    2004-02-01

    The radical-radical reaction dynamics of ground-state atomic oxygen [O(3P)] with propargyl radicals (C3H3) has first been investigated in a crossed beam configuration. The radical reactants O(3P) and C3H3 were produced by the photodissociation of NO2 and the supersonic flash pyrolysis of precursor propargyl bromide, respectively. A new exothermic channel of O(3P)+C3H3→C3H2+OH was identified and the nascent distributions of the product OH in the ground vibrational state (X 2Π:ν″=0) showed bimodal rotational excitations composed of the low- and high-N″ components without spin-orbit propensities. The averaged ratios of Π(A')/Π(A″) were determined to be 0.60±0.28. With the aid of ab initio theory it is predicted that on the lowest doublet potential energy surface, the reaction proceeds via the addition complexes formed through the barrierless addition of O(3P) to C3H3. The common direct abstraction pathway through a collinear geometry does not occur due to the high entrance barrier in our low collision energy regime. In addition, the major reaction channel is calculated to be the formation of propynal (CHCCHO)+H, and the counterpart C3H2 of the probed OH product in the title reaction is cyclopropenylidene (1c-C3H2) after considering the factors of barrier height, reaction enthalpy and structural features of the intermediates formed along the reaction coordinate. On the basis of the statistical prior and rotational surprisal analyses, the ratio of population partitioning for the low- and high-N″ is found to be about 1:2, and the reaction is described in terms of two competing addition-complex mechanisms: a major short-lived dynamic complex and a minor long-lived statistical complex. The observed unusual reaction mechanism stands in sharp contrast with the reaction of O(3P) with allyl radical (C3H5), a second significant conjugated hydrocarbon radical, which shows totally dynamic processes [J. Chem. Phys. 117, 2017 (2002)], and should be understood based

  17. Concentration of (3)H in plants around Fukushima Dai-ichi Nuclear Power Station.

    PubMed

    Kakiuchi, Hideki; Akata, Naofumi; Hasegawa, Hidenao; Ueda, Shinji; Tokonami, Shinji; Yamada, Masatoshi; Hosoda, Masahiro; Sorimachi, Atsuyuki; Tazoe, Hirofumi; Noda, Kaori; Hisamatsu, Shun'ichi

    2012-01-01

    A large amount of radionuclides was released from the Fukushima Dai-ichi Nuclear Power Station (FDNPS) following the damage caused by the tsunami due to the Great East Japan Earthquake on 11 March 2011. Although many radionuclides in various environmental samples around the FDNPS have been measured, (3)H in the terrestrial environment has not yet been reported. We present here the first survey results of (3)H concentrations in plant samples collected around the FDNPS in 2011 from shortly after the accident. The free-water (3)H concentrations in herbaceous plant shoots and evergreen tree leaves were considerably higher than the previous background concentration, and diminished with distance from the FDNPS. Although reconstruction of atmospheric (3)H concentrations after the accident is difficult, a rough estimate of the radiation dose due to (3)H inhalation about 20 km from the FDNPS is on the order of a few microsieverts (μSv).

  18. Quantum graphs: PT -symmetry and reflection symmetry of the spectrum

    NASA Astrophysics Data System (ADS)

    Kurasov, P.; Majidzadeh Garjani, B.

    2017-02-01

    Not necessarily self-adjoint quantum graphs—differential operators on metric graphs—are considered. Assume in addition that the underlying metric graph possesses an automorphism (symmetry) P . If the differential operator is P T -symmetric, then its spectrum has reflection symmetry with respect to the real line. Our goal is to understand whether the opposite statement holds, namely, whether the reflection symmetry of the spectrum of a quantum graph implies that the underlying metric graph possesses a non-trivial automorphism and the differential operator is P T -symmetric. We give partial answer to this question by considering equilateral star-graphs. The corresponding Laplace operator with Robin vertex conditions possesses reflection-symmetric spectrum if and only if the operator is P T -symmetric with P being an automorphism of the metric graph.

  19. Effect of xid on autoimmune C3H-gld/gld mice.

    PubMed

    Seldin, M F; Reeves, J P; Scribner, C L; Roths, J B; Davidson, W F; Morse, H C; Steinberg, A D

    1987-06-01

    The xid gene was introduced into C3H-gld/gld mice to determine its effects on the development of autoimmune disease. C3H-gld/gld.xid mice were compared with C3H-gld/gld mice for the development of lymphadenopathy, surface phenotype of lymph node (LN) cells, c-myb oncogene RNA production, serum immunoglobulin (Ig) levels, and autoantibody production. In addition, C3H-gld/gld and C3H-lpr/lpr mice were examined for serum Ig and autoantibody levels. The results showed that the xid gene had no effect on either the development of the severe lymphadenopathy characteristic of C3H-gld/gld mice or the phenotype of the Ly-2-, L3T4-, Ly-5(B220)+ T-cell subset that is expanded in the LN and spleens of these mice. Similarly, xid did not affect the high levels of c-myb oncogene RNA expression by C3H-gld/gld LN and spleen cells. By contrast, the xid gene caused a significant reduction in serum IgM but not IgA levels and almost completely ablated the generation of both IgM and IgG anti-ssDNA antibodies and anti-dsDNA antibodies. These data suggest that the xid gene can dramatically decrease the B-cell manifestations of autoimmunity in gld homozygotes without affecting their abnormal T-cell expansion. Comparisons of age-matched C3H-gld/gld and C3H-lpr/lpr mice showed that they had similarly elevated serum IgM and IgA levels and anti-ssDNA and anti-dsDNA antibody levels providing further evidence that gld and lpr produce parallel defects in C3H mice.

  20. Structure and Properties of High Symmetry Composites

    DTIC Science & Technology

    1990-07-27

    utilizing a 4-directional reinforcement. Reducing the close-to-cubic symmetry concept into practice in our laboratory by a three-dimensional braiding...modelled by utilizing the different elastic strain energy expressions produced by different combinations of symmetry elements. Symmetry in Materials The...rings is insignmicant. Utilizing the above assumptions, numerous textile structures possess holosymmetric cubic symmetry. This symmetry state is found in

  1. Structural Symmetry in Membrane Proteins.

    PubMed

    Forrest, Lucy R

    2015-01-01

    Symmetry is a common feature among natural systems, including protein structures. A strong propensity toward symmetric architectures has long been recognized for water-soluble proteins, and this propensity has been rationalized from an evolutionary standpoint. Proteins residing in cellular membranes, however, have traditionally been less amenable to structural studies, and thus the prevalence and significance of symmetry in this important class of molecules is not as well understood. In the past two decades, researchers have made great strides in this area, and these advances have provided exciting insights into the range of architectures adopted by membrane proteins. These structural studies have revealed a similarly strong bias toward symmetric arrangements, which were often unexpected and which occurred despite the restrictions imposed by the membrane environment on the possible symmetry groups. Moreover, membrane proteins disproportionately contain internal structural repeats resulting from duplication and fusion of smaller segments. This article discusses the types and origins of symmetry in membrane proteins and the implications of symmetry for protein function.

  2. Symmetry Guide to Ferroaxial Transitions

    NASA Astrophysics Data System (ADS)

    Hlinka, J.; Privratska, J.; Ondrejkovic, P.; Janovec, V.

    2016-04-01

    The 212 species of the structural phase transitions with a macroscopic symmetry breaking are inspected with respect to the occurrence of the ferroaxial order parameter, the electric toroidal moment. In total, 124 ferroaxial species are found, some of them being also fully ferroelectric (62) or fully ferroelastic ones (61). This ensures a possibility of electrical or mechanical switching of ferroaxial domains. Moreover, there are 12 ferroaxial species that are neither ferroelectric nor ferroelastic. For each species, we have also explicitly worked out a canonical form for a set of representative equilibrium property tensors of polar and axial nature in both high-symmetry and low-symmetry phases. This information was gathered into the set of 212 mutually different symbolic matrices, expressing graphically the presence of nonzero independent tensorial components and the symmetry-imposed links between them, for both phases simultaneously. Symmetry analysis reveals the ferroaxiality in several currently debated materials, such as VO2 , LuFe2 O4 , and URu2 Si2 .

  3. Dopamine D2 receptors labeled with ( sup 3 H)raclopride in rat and rabbit brains. Equilibrium binding, kinetics, distribution and selectivity

    SciTech Connect

    Dewar, K.M.; Montreuil, B.; Grondin, L.; Reader, T.A. )

    1989-08-01

    The binding properties of the substituted benzamide raclopride to dopamine D2 receptors were studied with membrane preparations from rat and rabbit neostriatum. An analysis of the association kinetics suggested a single binding site but the data from the dissociation experiments were better described by a two-site model. Examination of saturation curves at equilibrium revealed a single class of binding sites in the neostriatum from both species (rat: maximum binding capacity (Bmax) = 247 fmol/mg of protein; rabbit: Bmax = 337 fmol/mg of protein). In cortical regions known to possess a distinct dopaminergic innervation (piriform-entorhinal areas and cingulate cortex) the Bmax values ranged between 9 and 22 fmol/mg of protein. ({sup 3}H)Raclopride binding sites (less than 12 fmol/mg of protein) were also detectable in the dorsal and ventral hippocampus as well as in the somatosensory and visual cortices. The selectivity in the neostriatum was examined by competition experiments with dopaminergic drugs. The rank of potency of agonists and antagonists to displace ({sup 3}H)raclopride binding revealed its selectivity for the dopamine D2 receptor and was essentially the same for both species. Antagonist competition curves could be fitted to a single site but inhibition by agonists was better described assuming a two-site model. The stereospecificity of binding was demonstrated by the use of the enantiomer pairs. These results validate the utilization of the novel benzamide ({sup 3}H)raclopride as a selective marker of dopamine D2 receptors.

  4. Laboratory detection of the D3h isomer of carbon trioxide (CO3): Potential intermediate in the CO2 + O reaction in atmospheres

    NASA Astrophysics Data System (ADS)

    Jamieson, C.; Mebel, A.; Kaiser, R.

    Radiation induced degradation of oxygen-bearing molecules like ozone or carbon dioxide can liberate oxygen atoms that are electronically excited 1 D state and or superthermal high kinetic energy and may subsequently react with carbon dioxide in the atmospheres of Venus Mars or the Earth In this reaction the carbon trioxide CO 3 intermediate was found to form and has been subsequently included in many reaction models to explain the heavy isotope enrichment of stratospheric carbon dioxide on Earth and the regeneration of carbon dioxide on Mars both in the upper atmosphere and catalyzed in solid CO 2 surfaces Studies of the O 1 D CO 2 reaction show a nearly statistical rate of isotope exchange suggesting that the CO 3 intermediate may possess a high degree of symmetry From theoretical calculations and matrix isolation studies we know that the lowest energy CO 3 isomer has C 2v symmetry however the D 3h isomer lies only 0 1 kcal mol -1 higher in energy than the C 2v structure with an isomerization barrier of 4 4 kcal mol -1 thus interconversion of these two structures should readily occur To date the C 2v structure has been the only isomer that has been experimentally detected and therefore inclusion of the symmetric D 3h isomer in the isotope exchange models is only theoretical Here we present the first experimental detection of the D 3h isomer of carbon trioxide which was identified by two fundamental vibrational frequencies nu 1 and nu 5 using infrared

  5. Anomalous absorption in c-C_3H and c-C_3D radicals

    NASA Astrophysics Data System (ADS)

    Chandra, S.; Shinde, S. V.; Kegel, W. H.; Sedlmayr, E.

    Yamamoto et al. (1987) reported the first detection of the c-C_3H radical in TMC-1 through its transition 2_1 2 rightarrow 1_1 1 at 91.5 GHz. The column density of c-C_3H in TMC-1 was estimated to be 6 times 10^12 cm^-2, which is about one order of magnitude lower than that of the c-C_3H_2 which is ubiquitous in galactic objects. Mangum & Wootten (1990) detected c-C_3H through the transition 1_1 0 rightarrow 1_1 1 at 14.8 GHz in 12 additional galactic objects. The most probable production mechanism of both the c-C_3H and c-C_3H_2 in dark clouds is a common dissociation reaction of the C_3H_3^+ ion (Adams & Smith 1987). Although the c-C_3H is 0.8 eV less stable than its isomer l-C_3H, finding of comparable column densities of both the isomers in TMC-1 suggests that the formation rate for both, c-C_3H and l-C_3H, are of about the same order in the cosmic objects. The existence of a metastable isomer under interstellar conditions is a well known phenomenon in astronomy. The aim of this investigation is a quantitative estimate of relative line intensities under NLTE conditions. For wide ranges of physical parameters, where these molecules may be found, we have solved a set of statistical equilibrium equations coupled with the equations of radiative transfer in an on-the-spot approximation. For c-C_3H, we accounted for 51 energy levels connected by 207 radiative transitions and for c-C_3D, we accounted for 51 energy levels connected by 205 radiative transitions. Our results show that the 3_3 1 rightarrow 3_3 0 transition of c-C_3H and c-C_3D may be found in absorption against the cosmic microwave background (CMB). Furthermore, we found population inversion for the 1_1 0 rightarrow 1_1 1 transition. These findings may be useful in identifying these molecules in other cosmic objects, as well as for the determination of physical parameters in these objects.

  6. Accumulation of radioactivity after repeated infusion of 3H-adrenaline and 3H-noradrenaline in the rat as a model animal.

    PubMed

    Lepschy, M; Filip, T; Palme, R G

    2014-10-01

    Besides enzymatic inactivation, catecholamines bind non-enzymatically and irreversible to proteins. The physiological impact of these catecholamine adducts is still unclear. We therefore collected basic data about the distribution of catecholamine adducts in the rat after repeated intravenous administration of (3)H-adrenaline and (3)H-noradrenaline. In all animals radioactivity in blood increased until the last injection on Day 7 and decreased then slowly close to background values (plasma) or remained higher (erythrocytes). In all sampled tissues radioactivity could be found, but only in hair high amounts remained present even after 3 weeks. Half-life of rat serum albumin loaded with (3)H-adrenaline or (3)H-noradrenaline was not altered. This study provides basic knowledge about the distribution of catecholamines or their adducts, but physiological effects could not be demonstrated. However, for the first time deposition and accumulation of catecholamines (adducts) in the hair could be proven, suggesting that hair might be used for evaluating long term stress.

  7. A comparison of growth and development of three major agricultural insect pests infected with Heliothis virescens ascovirus 3h (HvAV-3h).

    PubMed

    Li, Shun-Ji; Wang, Xing; Zhou, Zhong-Shi; Zhu, Jie; Hu, Jue; Zhao, Yi-Pei; Zhou, Gui-Wei; Huang, Guo-Hua

    2013-01-01

    Ascoviruses are double-stranded DNA viruses that are pathogenic to lepidopteran hosts, particularly noctuid larvae. Infection of a larva is characterized by retarded growth, reduced feeding and yellowish body color. In this paper, we reported the growth and development of three major agricultural noctuid insect pests, Helicoverpa armigera (Hübner), Spodoptera exigua (Hübner) and Spodoptera litura (Fabricius), infected with Heliothis virescens ascovirus 3h (HvAV-3h). Using 10-fold serial dilutions (0 to 7) of HvAV-3h-containing hemolymph to infect S. litura larvae, we found no significant difference in larval mortalities from 0 to 10(3)-fold dilutions; however, significant differences were observed at 10(4)-fold dilution and above. Using a 10-fold dilution of HvAV-3h-containing hemolymph to infect H. armigera, S. exigua and S. litura larvae, we found that the growth and development were significantly affected. All infected larvae could not pupate; the survival times of treated H. armigera, S. litura and S. exigua larvae were significantly longer than untreated control larvae. Body weight showed significant difference between treated and untreated control group from day 1 after inoculation in H. armigera and S. exigua, but day 2 in S. litura. Additionally, food intake also showed significant difference between treated and untreated control group from day 2 after inoculation in H. armigera and S. litura, but day 3 in S. exigua.

  8. Interactions of dopamine and the release of [3H]-taurine and [3H]-glycine from the isolated retina of the rat.

    PubMed

    Pycock, C J; Smith, L F

    1983-02-01

    1 The dose-related, calcium-dependent, potassium-stimulated release of preloaded [(3)H]-dopamine from the superfused rat retina has been demonstrated.2 A high-affinity uptake system for dopamine exists in rat retina in vitro; K(m) value was calculated as 1.89 muM, V(max) value as 1.4 nmol g(-1) tissue h(-1).3 Dopamine (0.8 and 4 mM) inhibited the spontaneous release of [(3)H]-glycine from retina, and in the case of 0.8 mM dopamine this inhibitory effect was antagonized by 10 muM (+)-butaclamol but not by 10 muM (-)-butaclamol.4 The potassium-evoked (25 mM) release of [(3)H]-glycine from rat retina was similarly inhibited by dopamine (0.4-4 mM) in a dose-related manner when added to the superfusate with the potassium. The effect of 0.8 mM dopamine was antagonized by 10 muM (+)-butaclamol but not by 10 muM (-)-butaclamol.5 Dopamine (4 mM) significantly reduced the spontaneous release of [(3)H]-taurine from rat retina.6 The potassium-stimulated (25 mM) release of [(3)H]-taurine occurred after the cessation of the depolarizing stimulus. This delayed release of [(3)H]-taurine was unaffected if dopamine was applied to the superfusate at the same time as the potassium, but it was significantly reduced if dopamine (0.8 and 4 mM) was applied after the depolarizing stimulus had been removed and during the actual amino acid release phase.7 The inhibition of K(+)-stimulated (25 mM) delayed release of [(3)H]-taurine by applying dopamine (0.8 mM) after the depolarizing stimulus was blocked by 10 muM (+)-butaclamol but not by 10 muM (-)-butaclamol.8 The results are discussed with respect to the possible neurotransmitter role for dopamine within the rat retina, and its possible interaction with glycine and taurine.

  9. Resonantly amplified vibronic symmetry breaking

    NASA Astrophysics Data System (ADS)

    Poliakoff, E. D.; Rathbone, G. J.; Bozek, J. D.; Lucchese, R. R.

    2002-05-01

    In photoelectron spectroscopy, it is normally assumed that excitation of a single quantum of a non-totally symmetric vibrational mode is forbidden owing to symmetry constraints. Using vibrationally resolved photoelectron spectroscopy over a broad spectral range, we have shown that a previously overlooked mechanism can lead to these nominally forbidden transitions. Specifically, the photoelectron can mediate the oscillator strength for such a transition via resonantly amplified vibronic symmetry breaking, and this effect results from intrachannel rather than interchannel coupling. In our first experiments, we focused on bending excitation accompanying CO2 photoionization. Photoelectron spectroscopy on the CO_2^+(C^2Σ_g^+) state showed that the excitation of the (010) vibrational mode is mediated by a shape resonant continuum electron. The degree of vibrational excitation can be substantial, and extensions to other types of symmetry breaking are currently being investigated.

  10. High affinity binding of (/sup 3/H)cocaine to rat liver microsomes

    SciTech Connect

    El-Maghrabi, E.A.; Calligaro, D.O.; Eldefrawi, M.E.

    1988-01-01

    )/sup 3/H)cocaine bound reversible, with high affinity and stereospecificity to rat liver microsomes. Little binding was detected in the lysosomal, mitochondrial and nuclear fractions. The binding kinetics were slow and the kinetically calculated K/sub D/ was 2 nM. Induction of mixed function oxidases by phenobarbital did not produce significant change in (/sup 3/H)cocaine binding. On the other hand, chronic administration of cocaine reduced (/sup 3/H)cocaine binding drastically. Neither treatment affected the affinity of the liver binding protein for cocaine. Microsomes from mouse and human livers had less cocaine-binding protein and lower affinity for cocaine than those from rat liver. Binding of (/sup 3/H)cocaine to rat liver microsomes was insensitive to monovalent cations and > 10 fold less sensitive to biogenic amines than the cocaine receptor in rat striatum. However, the liver protein had higher affinity for cocaine and metabolites except for norcocaine. Amine uptake inhibitors displaced (/sup 3/H)cocaine binding to liver with a different rank order of potency than their displacement of (/sup 3/H)cocaine binding to striatum. This high affinity (/sup 3/H)cocaine binding protein in liver is not likely to be monooxygenase, but may have a role in cocaine-induced hepatotoxicity

  11. In vivo binding of /sup 3/H-N-methylspiperone to dopamine and serotonin receptors

    SciTech Connect

    Frost, J.J.; Smith, A.C.; Kuhar, M.J.; Dannals, R.F.; Wagner, H.N. Jr.

    1987-03-09

    /sup 3/H-N-methylspiperone (/sup 3/H-NMSP) was used to label dopamine-2 and serotonin-2 in vivo in the mouse. The striatum/cerebellum binding ratio reached a maximum of 80 eight hours after intravenous administration of /sup 3/H-NMSP. The frontal cortex/cerebellum ratio was 5 one hour after injection. The binding of /sup 3/H-NMSP was saturable in the frontal cortex and cerebellum between doses of 10 and 1000 ..mu..g/kg. Between 0.01 and 10 ..mu..g/kg the ratio total/nonspecific binding increased from 14 to 21. Inhibition of /sup 3/H-NMSP binding in the frontal cortex and striatum by ketanserin, a selective serotonin-2 antagonist, demonstrated that 20% of the total binding in the striatum was to serotonin-2 rectors and 91% of the total binding in the frontal cortex was to serotonin-2 receptors. Compared to /sup 3/H-spiperone, /sup 3/H-NMSP 1) results in a much higher specific/nonspecific binding ratio in the striatum and frontal cortex and 2) displays more than a two-fold higher brain uptake. 18 references, 4 figures.

  12. Ascorbic acid enables reversible dopamine receptor /sup 3/H-agonist binding

    SciTech Connect

    Leff, S.; Sibley, D.R.; Hamblin, M.; Creese, I.

    1981-11-16

    The effects of ascorbic acid on dopaminergic /sup 3/H-agonist receptor binding were studied in membrane homogenates of bovine anterior pituitary and caudate, and rat striatum. In all tissues virtually no stereospecific binding (defined using 1uM (+)butaclamol) of the /sup 3/H-agonists N-propylnorapomorphine (NPA), apomorphine, or dopamine could be demonstrated in the absence of ascorbic acid. Although levels of total /sup 3/H-agonist binding were three to five times greater in the absence than in the presence of 0.1% ascorbic acid, the increased binding was entirely non-stereospecific. Greater amounts of dopamine-inhibitable /sup 3/H-NPA binding could be demonstrated in the absence of 0.1% ascorbic acid, but this measure of ''specific binding'' was demonstrated not to represent dopamine receptor binding since several other catecholamines and catechol were equipotent with dopamine and more potent than the dopamine agonist (+/-)amino-6,7-dihydroxy-1,2,3,4-tetrahydronapthalene (ADTN) in inhibiting this binding. High levels of dopamine-displaceable /sup 3/H-agonist binding were detected in fresh and boiled homogenates of cerebellum, an area of brain which receives no dopaminergic innervation, further demonstrating the non-specific nature of /sup 3/H-agonist binding in the absence of ascorbic acid. These studies emphasize that under typical assay conditions ascorbic acid is required in order to demonstrate reversible and specific /sup 3/H-agonist binding to dopamine receptors.

  13. Characterization of rat brain opioid receptors by (Tyr-3,5-/sup 3/H)1, D-Ala2, Leu5-enkephalin binding

    SciTech Connect

    Benyhe, S.; Toth, G.; Kevei, J.; Szuecs, M.B.; Borsodi, A.; Di Gleria, K.; Szecsi, J.; Sueli-Vargha, H.M.; Medzihradszky, K.

    1985-05-01

    (Tyr-3,5-/sup 3/H)1, D-Ala2, Leu5-enkephalin ((/sup 3/H)DALA) was used for labeling the opioid receptors of rat brain plasma membranes. The labeled ligand was prepared from (Tyr-3,5-diiodo)1, D-Ala2, Leu5-enkephalin by catalytic reductive dehalogenation in the presence of Pd catalyst. The resulting (Tyr-3,5-/sup 3/H)1, D-Ala2, Leu5-enkephalin had a specific activity of 37.3 Ci/mmol. In the binding experiments steady-state level was reached at 24 degrees C within 45 min. The pseudo first order association rate constant was 0.1 min-1. The dissociation of the receptor-ligand complex was biphasic with k-1-s of 0.009 and 0.025 min-1. The existence of two binding sites was proved by equilibrium studies. The high affinity site showed a KD = 0.7 nM and Bmax = 60 fmol/mg protein; the low affinity site had a KD = 5 nM and Bmax = 160 fmol/mg protein. A series of opioid peptides inhibited (/sup 3/H)DALA binding more efficiently than morphine-like drugs suggesting that labeled ligand binds preferentially to the delta subtype of opioid receptors. Modification of the original peptides either at the C or N terminal ends of the molecules resulted in a decrease in their affinity.

  14. Demonstration of non-opioid sigma binding with (d)/sup 3/H-SKF 10047 in guinea pig brain

    SciTech Connect

    Mickelson, M.M.; Lahti, R.A.

    1985-02-01

    A non-opioid binding site to (d)/sup 3/H-SKF 10047 (N-allyl-normetazocine), the prototypic ligand for the sigma or PCP-like receptor, was demonstrated. The (d) isomer of /sup 3/H-SKF 10047 was used to demonstrate a stereospecific low affinity binding site with a K/sub d/ of 173nM. It was naloxone insensitive with an IC/sup 50/ of greater than 10,000nM, which defined it as non-opioid. Traditional mu compounds like morphine and FK 33824 were also inactive, with IC/sup 50/'s of greater than 10,000nM. Kappa compounds such as ethylketocyclazocine and U-50,488H were active as were all of the benzmorphans tested, with butorphanol the least active. The known antipsychotic haloperidol was the most active compound tested, with an IC/sup 50/ of 11nM. Other antipsychotics which demonstrated activity were chlorpromazine and pimozide. The atypical antipsychotic clozapine was inactive.

  15. Symmetries of coupled harmonic oscillators

    NASA Technical Reports Server (NTRS)

    Han, D.; Kim, Y. S.

    1993-01-01

    It is shown that the system of two coupled harmonic oscillators possesses many interesting symmetries. It is noted that the symmetry of a single oscillator is that of the three-parameter group Sp(2). Thus two uncoupled oscillator exhibits a direct product of two Sp(2) groups, with six parameters. The coupling can be achieved through a rotation in the two-dimensional space of two oscillator coordinates. The closure of the commutation relations for the generators leads to the ten-parameter group Sp(4) which is locally isomorphic to the deSitter group O(3,2).

  16. Iterates of maps with symmetry

    NASA Technical Reports Server (NTRS)

    Chossat, Pascal; Golubitsky, Martin

    1988-01-01

    Fixed-point bifurcation, period doubling, and Hopf bifurcation (HB) for iterates of equivariant mappings are investigated analytically, with a focus on HB in the presence of symmetry. An algebraic formulation for the hypotheses of the theorem of Ruelle (1973) is derived, and the case of standing waves in a system of ordinary differential equations with O(2) symmetry is considered in detail. In this case, it is shown that HB can lead directly to motion on an invariant 3-torus, with an unexpected third frequency due to drift of standing waves along the torus.

  17. The Broken Symmetry of Time

    SciTech Connect

    Kastner, Ruth E.

    2011-11-29

    This paper seeks to clarify features of time asymmetry in terms of symmetry breaking. It is observed that, in general, a contingent situation or event requires the breaking of an underlying symmetry. The distinction between the universal anisotropy of temporal processes and the irreversibility of certain physical processes is clarified. It is also proposed that the Transactional Interpretation of quantum mechanics offers an effective way to explain general thermodynamic asymmetry in terms of the time asymmetry of radiation, where prior such efforts have fallen short.

  18. Quantum Symmetries and Exceptional Collections

    NASA Astrophysics Data System (ADS)

    Karp, Robert L.

    2011-01-01

    We study the interplay between discrete quantum symmetries at certain points in the moduli space of Calabi-Yau compactifications, and the associated identities that the geometric realization of D-brane monodromies must satisfy. We show that in a wide class of examples, both local and compact, the monodromy identities in question always follow from a single mathematical statement. One of the simplest examples is the {{mathbb Z}_5} symmetry at the Gepner point of the quintic, and the associated D-brane monodromy identity.

  19. Symmetry analysis of cellular automata

    NASA Astrophysics Data System (ADS)

    García-Morales, V.

    2013-01-01

    By means of B-calculus [V. García-Morales, Phys. Lett. A 376 (2012) 2645] a universal map for deterministic cellular automata (CAs) has been derived. The latter is shown here to be invariant upon certain transformations (global complementation, reflection and shift). When constructing CA rules in terms of rules of lower range a new symmetry, “invariance under construction” is uncovered. Modular arithmetic is also reformulated within B-calculus and a new symmetry of certain totalistic CA rules, which calculate the Pascal simplices modulo an integer number p, is then also uncovered.

  20. Chiral symmetry in quarkyonic matter

    SciTech Connect

    Kojo, T.

    2012-05-15

    The 1/N{sub c} expansion classifies nuclear matter, deconfined quark matter, and Quarkyonic matter in low temperature region. We investigate the realization of chiral symmetry in Quarkyonic matter by taking into account condensations of chiral particle-hole pairs. It is argued that chiral symmetry and parity are locally violated by the formation of chiral spirals, <{psi}-bar exp (2i{mu}{sub q} z{gamma}{sup 0} {gamma}{sup z}){psi}> . An extension to multiple chiral spirals is also briefly discussed.

  1. Bell Inequalities and Group Symmetry

    NASA Astrophysics Data System (ADS)

    Bolonek-Lasoń, Katarzyna

    2017-03-01

    Recently the method based on irreducible representations of finite groups has been proposed as a tool for investigating the more sophisticated versions of Bell inequalities (V. Ugǔr Gűney, M. Hillery, Phys. Rev. A90, 062121 ([2014]) and Phys. Rev. A91, 052110 ([2015])). In the present paper an example based on the symmetry group S 4 is considered. The Bell inequality violation due to the symmetry properties of regular tetrahedron is described. A nonlocal game based on the inequalities derived is described and it is shown that the violation of Bell inequality implies that the quantum strategies outperform their classical counterparts.

  2. Nonsupersymmetric Dualities from Mirror Symmetry

    NASA Astrophysics Data System (ADS)

    Kachru, Shamit; Mulligan, Michael; Torroba, Gonzalo; Wang, Huajia

    2017-01-01

    We study supersymmetry breaking perturbations of the simplest dual pair of (2 +1 )-dimensional N =2 supersymmetric field theories—the free chiral multiplet and N =2 super QED with a single flavor. We find dual descriptions of a phase diagram containing four distinct massive phases. The equivalence of the intervening critical theories gives rise to several nonsupersymmetric avatars of mirror symmetry: we find dualities relating scalar QED to a free fermion and Wilson-Fisher theories to both scalar and fermionic QED. Thus, mirror symmetry can be viewed as the multicritical parent duality from which these nonsupersymmetric dualities directly descend.

  3. Chiral symmetry on the lattice

    SciTech Connect

    Creutz, M.

    1994-11-01

    The author reviews some of the difficulties associated with chiral symmetry in the context of a lattice regulator. The author discusses the structure of Wilson Fermions when the hopping parameter is in the vicinity of its critical value. Here one flavor contrasts sharply with the case of more, where a residual chiral symmetry survives anomalies. The author briefly discusses the surface mode approach, the use of mirror Fermions to cancel anomalies, and finally speculates on the problems with lattice versions of the standard model.

  4. Intraneuronal accumulation and persistence of radiolabel in rat brain following in vivo administration of [3H]-chlorisondamine.

    PubMed Central

    el-Bizri, H.; Rigdon, M. G.; Clarke, P. B.

    1995-01-01

    1. Chlorisondamine (CHL), a bisquaternary amine, produces a remarkably long-lasting blockade of central responses to nicotine. The mechanism underlying this blockade is not known. The main aim of this study was to test for possible accumulation of [3H]-CHL in rat brain during the period of chronic blockade. 2. Rats received CHL, either systemically (10 mg kg-1) or centrally (10 micrograms i.c.v.). Seven days later, striatal synaptosomes prepared from these animals were tested for nicotine-induced [3H]-dopamine release. This experiment showed that i.c.v. administration of CHL was as effective as systemic administration in producing ex vivo blockade of central nicotinic receptors. 3. Rats received bilateral i.c.v. infusions of [3H]-CHL (10 micrograms) and radioactivity was subsequently quantified in dissected cerebral cortex, striatum, hippocampus, midbrain and cerebellum. Radiolabel was detected at all three survival times (1, 7, and 21 days). Regional heterogeneity was apparent at 7 and 21 days survival. Radiolabel was almost exclusively confined to the insoluble subcellular fraction in all areas sampled. 4. The anatomical distribution of radiolabel was also visualized in brain sections. Rats received bilateral i.c.v. infusions of [3H]-CHL (10 micrograms) and were killed at 1, 7, 21 or 84 days. Immediately before they were killed, all rats were tested behaviourally, and central nicotinic blockade was demonstrated at 1, 7 and 21 days; partial recovery was observed at 84 days. Particularly at longer survival times, tritium was found to be heavily concentrated in the substantia nigra pars compacta, ventral tegmental area, dorsal raphé nucleus, and the granular layer of the cerebellum. 5. The possibility of retrograde axonal transport of radiolabel was then examined. Rats received a unilateral intrastriatal infusion of [3H]-CHL (0.34 or 0.034 micrograms) one week before they were killed. Autoradiographic labelling was largely confined to the site of infusion and to

  5. HIV-1 transgenic rats display an increase in [3H]dopamine uptake in the prefrontal cortex and striatum

    PubMed Central

    Zhu, Jun; Yuan, Yaxia; Midde, Narasimha M.; Gomez, Adrian M.; Sun, Wei-Lun; Quizon, Pamela M.; Zhan, Chang-Guo

    2017-01-01

    HIV viral proteins within the central nervous system are associated with the development of neurocognitive impairments in HIV-infected individuals. Dopamine transporter (DAT)-mediated dopamine transport is critical for normal dopamine homeostasis. Abnormal dopaminergic transmission has been implicated as a risk determinant of HIV-induced neurocognitive impairments. Our published work has demonstrated that Tat-induced inhibition of DAT is mediated by allosteric binding site(s) on DAT, not the interaction with the dopamine uptake site. The present study investigated whether impaired DAT function induced by Tat exposure in vitro can be documented in HIV-1 transgenic (HIV-1Tg) rats. We assessed kinetic analyses of [3H]dopamine uptake into prefrontal and striatal synaptosomes of HIV-1Tg and Fisher 344 rats. Compared with Fisher 344 rats, the capacity of dopamine transport in the prefrontal cortex (PFC) and striatum of HIV-1Tg rats was increased by 34% and 32%, respectively. Assessment of surface biotinylation indicated that DAT expression in the plasma membrane was reduced in PFC and enhanced in striatum, respectively, of HIV-1Tg rats. While the maximal binding sites (Bmax) of [3H]WIN 35,428 was decreased in striatum of HIV-1Tg rats, an increase in DAT turnover proportion was found, relative to Fisher 344 rats. Together, these findings suggest that neuroadaptive changes in DAT function are evidenced in the HIV-1Tg rats, perhaps compensating for viral protein-induced abnormal dopaminergic transmission. Thus, our study provides novel insights into understanding mechanism underlying neurocognitive impairment evident in neuroAIDS. PMID:26501780

  6. Specific labeling of O6-alkylguanine-DNA alkyltransferase by reaction with O6-(p-hydroxy[3H]methylbenzyl)guanine.

    PubMed

    Ciocco, G M; Moschel, R C; Chae, M Y; McLaughlin, P J; Zagon, I S; Pegg, A E

    1995-09-15

    O6-Alkylguanine-DNA alkyltransferase (AGT) is an important DNA repair protein that removes adducts from the O6 position of guanine by transferring them to a cysteine residue within its amino acid sequence. Mammalian AGTs are readily inactivated by incubation with O6-benzyl-guanine (BG), which is an alternative substrate for the protein. To examine this inactivation in more detail and to develop a procedure for the specific labeling of human AGT, we synthesized a BG derivative, O6-(p-hydroxy[3H]methylbenzyl_guanine ([3H]HMBG) and examined its interaction with AGT in HT29 cell extracts and in HT29 cells. Incubation of human AGT with [3H]HMBG led to the incorporation of radioactivity in the protein in a time- and temperature-dependent manner. This reaction was specific, since neither AGT that was first inactivated by reaction with BG nor proteins other than AGT were labeled. Digestion of the labeled AGT with trypsin showed that a single peptide contained the label. Sequencing of this peptide indicated that the label was bound to cysteine-145. These results demonstrate that AGT accepts HMBG as a substrate and becomes inactivated by transfer of a p-hydroxymethylbenzyl residue to the cysteine-145 acceptor site. When [3H]HMBG was added to cultures of HT29 cells which are Mer+ and express active AGT, radioactivity was incorporated in a macromolecule and could be detected by autoradiography. No such labeling occurred with BE or CHO cells, which are Mer- and lack AGT. Examination of the interaction of [3H]HMBG with mutant AGT proteins that differ greatly in their abilities to react with BG showed that there was a strong correlation between the reaction with BG and the labeling with [3H]HMBG. These results indicate that [3H]HMBG is a potentially useful reagent for the detection and localization of AGT activity and for the investigation of its mechanism of action.

  7. Use of 3H/3He ages to evaluate and improve groundwater flow models in a complex buried-valley aquifer

    USGS Publications Warehouse

    Sheets, R.A.; Bair, E.S.; Rowe, G.L.

    1998-01-01

    Combined use of the tritium/helium 3 (3H/3He) dating technique and particle-tracking analysis can improve flow-model calibration. As shown at two sites in the Great Miami buried-valley aquifer in southwestern Ohio, the combined use of 3H/3He age dating and particle tracking led to a lower mean absolute error between measured heads and simulated heads than in the original calibrated models and/or between simulated travel times and 3H/3He ages. Apparent groundwater ages were obtained for water samples collected from 44 wells at two locations where previously constructed finite difference models of groundwater flow were available (Mound Plant and Wright-Patterson Air Force Base (WPAFB)). The two-layer Mound Plant model covers 11 km2 within the buried-valley aquifer. The WPAFB model has three layers and covers 262 km2 within the buried-valley aquifer and adjacent bedrock uplands. Sampled wells were chosen along flow paths determined from potentiometric maps or particle-tracking analyses. Water samples were collected at various depths within the aquifer. In the Mound Plant area, samples used for comparison of 3H/3He ages with simulated travel times were from wells completed in the uppermost model layer. Simulated travel times agreed well with 3H/3He ages. The mean absolute error (MAE) was 3.5 years. Agreement in ages at WPAFB decreased with increasing depth in the system. The MAEs were 1.63, 17.2, and 255 years for model layers 1, 2, and 3, respectively. Discrepancies between the simulated travel times and 3H/3He ages were assumed to be due to improper conceptualization or incorrect parameterization of the flow models. Selected conceptual and parameter modifications to the models resulted in improved agreement between 3H/3He ages and simulated travel times and between measured and simulated heads and flows.

  8. Spin symmetry in the antinucleon spectrum.

    PubMed

    Zhou, Shan-Gui; Meng, Jie; Ring, P

    2003-12-31

    We discuss spin and pseudospin symmetry in the spectrum of single nucleons and single antinucleons in a nucleus. As an example we use relativistic mean field theory to investigate single antinucleon spectra. We find a very well developed spin symmetry in single antineutron and single antiproton spectra. The dominant components of the wave functions of the spin doublet are almost identical. This spin symmetry in antiparticle spectra and the pseudospin symmetry in particle spectra have the same origin. However, it turns out that the spin symmetry in antinucleon spectra is much better developed than the pseudospin symmetry in normal nuclear single particle spectra.

  9. Charge symmetry at the partonic level

    SciTech Connect

    Londergan, J. T.; Peng, J. C.; Thomas, A. W.

    2010-07-01

    This review article discusses the experimental and theoretical status of partonic charge symmetry. It is shown how the partonic content of various structure functions gets redefined when the assumption of charge symmetry is relaxed. We review various theoretical and phenomenological models for charge symmetry violation in parton distribution functions. We summarize the current experimental upper limits on charge symmetry violation in parton distributions. A series of experiments are presented, which might reveal partonic charge symmetry violation, or alternatively might lower the current upper limits on parton charge symmetry violation.

  10. Interactions of ( sup 3 H)amphetamine with rat brain synaptosomes. I. Saturable sequestration

    SciTech Connect

    Zaczek, R.; Culp, S.; Goldberg, H.; Mccann, D.J.; De Souza, E.B. )

    1991-05-01

    Previous studies have identified a saturable site of d-({sup 3}H)amphetamine sequestration (AMSEQ) in rat brain synaptosomes. The present study characterized AMSEQ with respect to its subcellular, neuronal and regional distributions, ontogenetic development, pharmacological specificity and factors required for its maintenance. Although AMSEQ was reduced when assays were performed in Krebs' buffer incubated at 37{degree}C as compared to assays performed in isotonic Tris-sucrose buffer incubated at room temperature, the pharmacological profiles of AMSEQ were virtually identical under both conditions. AMSEQ was negligible in tissues outside the central nervous system, enriched in synaptosomes and partially reduced by striatal kainic acid lesion, indicating neuronal localization. The distribution of AMSEQ in the central nervous system was heterogenous. Highest levels were present in hypothalamus with progressively lower levels noted in parietal cortex, frontal cortex, striatum, thalamus, hippocampus, midbrain, cerebellum, pons-medulla and spinal cord. With regard to its ontogeny, AMSEQ increased early in neonatal life, reaching adult levels by postnatal day 14. Although the effects of amphetamine to abolish the transynaptosomal pH gradient suggest a possible role for this gradient in the maintenance of AMSEQ, the pharmacological profile of AMSEQ indicates that other factors are involved. An interaction with an intrasynaptosomal acid, such as N-acetylaspartate, may account for AMSEQ maintenance. AMSEQ did not possess a stereospecific preference for either d-(IC50 = 177 microM) or I-amphetamine (IC50 = 173 microM). However, the pharmacological profile of AMSEQ indicated structural specificity with antidepressants being relatively potent inhibitors. (Abstract Truncated)

  11. Peptide displacement of ( sup 3 H)5-hydroxytryptamine binding to bovine cortical membranes

    SciTech Connect

    Takeuchi, Y.; Root-Bernstein, R.S.; Shih, J.C. )

    1990-12-01

    Chemical studies have demonstrated that peptides such as the encephalitogenic (EAE) peptide of myelin basic protein (MBP) and luteinizing hormone-releasing hormone (LHRH) can bind serotonin (5-hydroxytryptamine, 5-HT) in vitro. The present research was undertaken to determine whether such binding interferes with 5-HT binding to its 5-HT1 receptors on bovine cerebral cortical membranes. EAE peptide and LHRH displaced ({sup 3}H)5-HT with IC50s of 4.0 x 10(-4) and 1.8 x 10(-3) M respectively. MBP itself also showed apparent displacing ability with an IC50 of 6.0 x 10(-5) M, though it also caused aggregation of cortical membranes that might have interfered with normal receptor binding. These results support previous suggestions that the tryptophan peptide region of MBP may act as a 5-HT receptor in the neural system. We also tested the effects of muramyl dipeptide (N-acetyl-muramyl-L-Ala-D-isoGln, MD), a bacterial cell-wall breakdown product that acts as a slow-wave sleep promoter, binds to LHRH and EAE peptide, and competes for 5-HT binding sites on macrophages. It showed no significant displacement of 5-HT binding to cortical membranes (IC50 greater than 10(-1) M), but its D-Ala analogue did (IC50 = 1.7 x 10(-3) M). Thus, it seems likely that the 5-HT-related effects of naturally occurring muramyl peptides are physiologically limited by receptor types.

  12. Turning Students into Symmetry Detectives

    ERIC Educational Resources Information Center

    Wilders, Richard; VanOyen, Lawrence

    2011-01-01

    Exploring mathematical symmetry is one way of increasing students' understanding of art. By asking students to search designs and become pattern detectives, teachers can potentially increase their appreciation of art while reinforcing their perception of the use of math in their day-to-day lives. This article shows teachers how they can interest…

  13. Platonic Symmetry and Geometric Thinking

    ERIC Educational Resources Information Center

    Zsombor-Murray, Paul

    2007-01-01

    Cubic symmetry is used to build the other four Platonic solids and some formalism from classical geometry is introduced. Initially, the approach is via geometric construction, e.g., the "golden ratio" is necessary to construct an icosahedron with pentagonal faces. Then conventional elementary vector algebra is used to extract quantitative…

  14. Circular codes, symmetries and transformations.

    PubMed

    Fimmel, Elena; Giannerini, Simone; Gonzalez, Diego Luis; Strüngmann, Lutz

    2015-06-01

    Circular codes, putative remnants of primeval comma-free codes, have gained considerable attention in the last years. In fact they represent a second kind of genetic code potentially involved in detecting and maintaining the normal reading frame in protein coding sequences. The discovering of an universal code across species suggested many theoretical and experimental questions. However, there is a key aspect that relates circular codes to symmetries and transformations that remains to a large extent unexplored. In this article we aim at addressing the issue by studying the symmetries and transformations that connect different circular codes. The main result is that the class of 216 C3 maximal self-complementary codes can be partitioned into 27 equivalence classes defined by a particular set of transformations. We show that such transformations can be put in a group theoretic framework with an intuitive geometric interpretation. More general mathematical results about symmetry transformations which are valid for any kind of circular codes are also presented. Our results pave the way to the study of the biological consequences of the mathematical structure behind circular codes and contribute to shed light on the evolutionary steps that led to the observed symmetries of present codes.

  15. Baryon and chiral symmetry breaking

    SciTech Connect

    Gorsky, A.; Krikun, A.

    2014-07-23

    We briefly review the generalized Skyrmion model for the baryon recently suggested by us. It takes into account the tower of vector and axial mesons as well as the chiral symmetry breaking. The generalized Skyrmion model provides the qualitative explanation of the Ioffe’s formula for the baryon mass.

  16. From symmetries to number theory

    SciTech Connect

    Tempesta, P.

    2009-05-15

    It is shown that the finite-operator calculus provides a simple formalism useful for constructing symmetry-preserving discretizations of quantum-mechanical integrable models. A related algebraic approach can also be used to define a class of Appell polynomials and of L series.

  17. The Symmetry of Natural Laws.

    ERIC Educational Resources Information Center

    Brown, Laurie M.

    This document is a monograph intended for advanced undergraduate students, or beginning graduate students, who have some knowledge of modern physics as well as classical physics, including the elementary quantum mechanical treatment of the hydrogen atom and angular momentum. The first chapter introduces symmetry and relates it to the mathematical…

  18. Resonantly amplified vibronic symmetry breaking

    NASA Astrophysics Data System (ADS)

    Rathbone, G. J.; Poliakoff, E. D.; Bozek, John D.; Lucchese, R. R.

    2001-05-01

    The energy dependence of the vibrational branching ratio for exciting one quantum of bending is determined for CO2 4σg-1 photoionization. This nominally forbidden transition becomes allowed for a photoionization transition as a result of instantaneous symmetry breaking due to zero point motion, and is strongly enhanced by a continuum shape resonance.

  19. Hidden local symmetry and beyond

    NASA Astrophysics Data System (ADS)

    Yamawaki, Koichi

    Gerry Brown was a godfather of our hidden local symmetry (HLS) for the vector meson from the birth of the theory throughout his life. The HLS is originated from very nature of the nonlinear realization of the symmetry G based on the manifold G/H, and thus is universal to any physics based on the nonlinear realization. Here, I focus on the Higgs Lagrangian of the Standard Model (SM), which is shown to be equivalent to the nonlinear sigma model based on G/H = SU(2)L ×SU(2)R/SU(2)V with additional symmetry, the nonlinearly-realized scale symmetry. Then, the SM does have a dynamical gauge boson of the SU(2)V HLS, “SM ρ meson”, in addition to the Higgs as a pseudo-dilaton as well as the NG bosons to be absorbed in to the W and Z. Based on the recent work done with Matsuzaki and Ohki, I discuss a novel possibility that the SM ρ meson acquires kinetic term by the SM dynamics itself, which then stabilizes the skyrmion dormant in the SM as a viable candidate for the dark matter, what we call “dark SM skyrmion (DSMS)”.

  20. Monster symmetry and extremal CFTs

    NASA Astrophysics Data System (ADS)

    Gaiotto, Davide

    2012-11-01

    We test some recent conjectures about extremal selfdual CFTs, which are the candidate holographic duals of pure gravity in AdS 3. We prove that no c = 48 extremal selfdual CFT or SCFT may possess Monster symmetry. Furthermore, we disprove a recent argument against the existence of extremal selfdual CFTs of large central charge.

  1. Superdeformations and fermion dynamical symmetries

    SciTech Connect

    Wu, Cheng-Li . Dept. of Physics and Atmospheric Science Tennessee Univ., Knoxville, TN . Dept. of Physics and Astronomy Joint Inst. for Heavy Ion Research, Oak Ridge, TN )

    1990-01-01

    In this talk, I will present a link between nuclear collective motions and their underlying fermion dynamical symmetries. In particular, I will focus on the microscopic understanding of deformations. It is shown that the SU{sub 3} of the one major shell fermion dynamical symmetry model (FDSM) is responsible for the physics of low and high spins in normal deformation. For the recently observed phenomena of superdeformation, the physics of the problem dictates a generalization to a supershell structure (SFDSM), which also has an SU{sub 3} fermion dynamical symmetry. Many recently discovered feature of superdeformation are found to be inherent in such an SU{sub 3} symmetry. In both cases the dynamical Pauli effect plays a vital role. A particularly noteworthy discovery from this model is that the superdeformed ground band is not the usual unaligned band but the D-pair aligned (DPA) band, which sharply crosses the excited bands. The existence of such DPA band is a key point to understand many properties of superdeformation. Our studies also poses new experimental challenge. This is particularly interesting since there are now plans to build new and exciting {gamma}-ray detecting systems, like the GAMMASPHERE, which could provide answers to some of these challenges. 34 refs., 11 figs., 5 tabs.

  2. Characterization of binding properties to human P-glycoprotein: development of a [3H]verapamil radioligand-binding assay.

    PubMed

    Döppenschmitt, S; Langguth, P; Regårdh, C G; Andersson, T B; Hilgendorf, C; Spahn-Langguth, H

    1999-01-01

    Interaction with the exsorptive transporter P-glycoprotein (P-gp) is a possible source of peculiarities in drug pharmacokinetics, including dose-dependent absorption, drug-drug interactions, intestinal secretion, and limited permeability of the blood-brain barrier. Among the established in vitro methods of the analysis of drug interactions with P-gp, none directly quantifies the affinity of ligands with P-gp. Instead, they measure the result of a membrane permeation and a receptor-binding process; this may lead to difficulties in the interpretation of results. An assay for quantification of drug affinity to the transporter is presented on the basis of the radioligand-binding assay principle. This has the advantage of directly quantifying the interaction between drugs and P-gp. Because of the reversible and competitive interaction of numerous substrates with P-gp, a radioligand-binding assay was developed by taking [3H]verapamil and [3H]vinblastine as radioligands and the human intestinal Caco-2 cells, overexpressed with P-gp by culturing in the presence of vinblastine or transfecting with multidrug resistance gene MDR-1 as receptor preparation. The assay was performed in 96-well plates and has the potential to be used as a high-throughput method. A clear induction of the expression of P-gp was demonstrated in the Caco-2 cells grown in the presence of vinblastine, as well as in the transfected cells, although to a lesser extent. Both radioligands were shown to bind to P-gp. Verapamil was the radioligand of choice for further investigations due to its lower nonspecific binding to the transporter preparation. Kinetics as well as specificity of the binding of verapamil to the P-gp preparation were demonstrated. A two-affinity model was found to adequately describe the data derived from saturation as well as from competition experiments, in accordance with previous findings on two exsorption sites for P-gp. The binding properties of [3H]verapamil and [3H]vinblastine to

  3. Potent enhancement of (/sup 3/H)nitrendipine binding in rat cerebral cortical and cardiac homogenates: a putative mechanism for the action of MDL 12,330A

    SciTech Connect

    Lee, H.R.; Jaros, J.A.; Roeske, W.R.; Wiech, N.L.; Ursillo, R.; Yamamura, H.I.

    1985-06-01

    (/sup 3/H)Nitrendipine ((/sup 3/H)NTD), a specific high-affinity calcium channel antagonist, was used to label dihydropyridine binding sites associated with calcium channels in rat cerebral cortical and cardiac homogenates. A novel lactamimide compound, MDL 12,330A, has been shown previously to have negative inotropic and chronotropic effects in isolated working guinea-pig hearts and these effects are reversed by the administration of calcium. MDL 12,330A is potent in enhancing (/sup 3/H)NTD binding in membranes prepared from the cerebral cortex and the heart, with EC50 values of 6.1 X 10(-8) and 3.4 X 10(-8) M, respectively, at 37 degrees C. This allosteric effect by MDL 12,330A is similar to that produced by a known calcium channel antagonist, d-cis diltiazem, which has been shown previously to enhance (/sup 3/H)NTD binding at 37 degrees C. The extent of enhancement by MDL 12,330A depends on incubation temperature (37 degrees C greater than 25 degrees C greater than 0 degrees C). The mechanism of this enhancement by MDL 12,330A is due to a decrease in the dissociation rate constant of the dihydropyridine-calcium channel supramolecular complex. MDL 12,330A is the most potent drug thus far examined which demonstrates the enhancement of (/sup 3/H)NTD binding.

  4. Increased Clearance and Degradation of [3H]Insulin in Streptozotocin Diabetic Rats

    PubMed Central

    Philippe, Jacques; Halban, Philippe A.; Gjinovci, Asllan; Duckworth, William C.; Estreicher, Jurek; Renold, Albert E.

    1981-01-01

    The role of the insulin-receptor compartment in the pharmacokinetics of intravenously injected insulin in rats was studied. Since streptozotocin-diabetes in rats results in increased insulin binding to tissues in vitro, insulin pharmacokinetics in streptozotocin-diabetic rats were compared to controls, using semisynthetic [3H]insulin as the tracer. The initial distribution volume for [3H]insulin was elevated by 60% in diabetic rats. By contrast, no difference in initial distribution volume for [14C]inulin was observed, and the absolute values were lower than those found for [3H]insulin. The metabolic clearance rate of [3H]insulin was elevated by 44% in diabetic rats. That these differences were the result of increased binding of insulin to a specific receptor compartment in diabetic rats was shown by three additional experiments. The first involved receptor saturation by injection of 10 U native insulin 2 min before the tracer injection, resulting in identical [3H]insulin disappearance rates in the two groups of rats. The second consisted of displacing [3H]insulin from receptors by injecting 10 U unlabeled insulin 6 min after the tracer injection. Displacement of intact [3H]insulin from receptors and subsequent reappearance in the circulation occurred in both control and diabetic animals; however, such displacement was 25% greater in the diabetic rats. Finally, treatment of diabetic rats with insulin for 8 d normalized [3H]insulin clearance even though the tracer was injected at a time when the animals were again hyperglycemic and hypoinsulinemic. This suggests that down-regulation of insulin receptors had occurred during insulin therapy. These results confirm that a specific compartment for insulin exists (the insulin-receptor compartment) and that this compartment plays an important role in insulin clearance. PMID:6451633

  5. N-(/sup 3/H)acetyl-labeling, a convenient method for radiolabeling of glycosaminoglycans

    SciTech Connect

    Hook, M.; Riesenfeld, J.; Lindahl, U.

    1982-01-15

    A method for the introduction of N-(/sup 3/H)acetyl groups into glycosaminoglycans is described. The procedure is based on (/sup 3/H)acetylation of N-unsubstituted hexosamine residues by treating the polysaccharides with (/sup 3/H)acetic anhydride. Preparations of heparin and heparin sulfate were found to contain significant numbers of N-unsubstituted hexosamine residues, as isolates. In contrast, such units could not be detected in chondroitin sulfate, dermatan sulfate, or hyaluronic acid. These polysaccharides were therefore subjected to partial N-deacetylation by reaction with hydrazine in the presence of hydrazine sulfate. After treatment with (/sup 3/H)acetic anhydride, the specific activities of the resulting labeled polysaccharide preparations ranged between 0.1 X 10/sup 6/ and 0.6 X 10/sup 6/ cpm /sup 3/H/..mu..g of uronic acid. The /sup 3/H-labeled polysaccharide preparations did not differ significantly from the corresponding unlabeled starting materials with regard to polyanion properties (chromatography on DEAE-cellulose) or polymer chain size (gel chromatography). Further, the radiolabeled polysaccharide derivatives were susceptible to specific enzymatic degradation (chondroitinase ABC and mammalian heparitinase) and retained their ability to interact specifically with certain proteins - for example, (/sup 3/H)heparin with antithrombin (/sup 3/H)hyaluronic acid oligosaccharides with chondroitin sulfate proteoglycan. These findings indicate that the labeling procedures did not induce any major structural derangement of the polysaccharide molecules. The method developed should be useful in providing labeled glycosaminoglycans for metabolic and enzymatic experiments as well as for studies on the interacion between glycosaminoglycans and other bilogical macromolecules.

  6. Low energy n-{sup 3}H scattering: A novel testground for nuclear interactions

    SciTech Connect

    Lazauskas, R.; Carbonell, J.; Fonseca, A.C.; Viviani, M.; Kievsky, A.; Rosati, S.

    2005-03-01

    Low energy n-{sup 3}H elastic cross sections near the resonance peak are calculated by solving the four-nucleon problem with realistic NN interactions. Three different methods - Alt, Grassberger, and Shandas; hyperspherical harmonics; and Faddeev-Yakubovsky - have been used and their respective results are compared. We conclude on a failure of the existing NN forces to reproduce the n-{sup 3}H total cross section.

  7. Photodisintegration of /sup 3/H and /sup 3/He. [Threshold to 25 MeV

    SciTech Connect

    Faul, D.D.

    1980-09-01

    The photoneutron cross sections for /sup 3/H and /sup 3/He have been measured from threshold to approx. 25 MeV with monoenergetic photons from the annihilation in flight of fast positrons at the LLL Electron-Positron Linear Accelerator facility. These reactions include the two-body breakup of /sup 3/H and the three-body breakup of both /sup 3/H and /sup 3/He; these measurements for /sup 3/H are the first to span the energy region across the peaks of the cross sections. An efficient BF/sub 3/-tube-and-paraffin neutron detector and high-pressure gaseous samples of several moles each (the activity of the /sup 3/H sample was approx. 200,000 Ci) were employed in these measurements. Measurements on /sup 16/O and /sup 2/H also were performed to verify the absolute cross-section scale. The results, when compared with each other and with results for the two-body breakup cross section for /sup 3/He from the literature, show that the two-body breakup cross sections for /sup 3/H and /sup 3/He have nearly the same shape, but the one for /sup 3/He lies lower in magnitude; the three-body breakup cross section for /sup 3/He lies higher in magnitude and is broader in the peak region and also rises less sharply from threshold than that for /sup 3/H; and these measured differences between the cross sections for the breakup modes largely compensate in their sum, so that the total photon absorption cross sections for /sup 3/H and /sup 3/He are nearly the same in both size and shape at energies near and above their peaks. Theoretical results from the literature disagree with the experimental results to a certain extent over the entire photon-energy region for which the photoneutron cross sections were measured. 50 figures, 7 tables.

  8. First Detection of c-C3H2 in a Circumstellar Disk

    NASA Astrophysics Data System (ADS)

    Qi, Chunhua; Öberg, Karin I.; Wilner, David J.; Rosenfeld, Katherine A.

    2013-03-01

    We report the first detection of c-C3H2 in a circumstellar disk. The c-C3H2 J = 6-5 line (217.882 GHz) is detected and imaged through Atacama Large Millimeter Array (ALMA) Science Verification observations toward the disk around the Herbig Ae star HD 163296 at 0.''8 resolution. The emission is consistent with that arising from a Keplerian rotating disk. Two additional c-C3H2 transitions are also tentatively detected, bolstering the identification of this species, but with insufficient signal-to-noise ratio to constrain the spatial distribution. Using a previously developed model for the physical structure of this disk, we fit a radial power-law distribution model to the c-C3H2 6-5 emission and find that c-C3H2 is present in a ring structure from an inner radius of about 30 AU to an outer radius of about 165 AU. The column density is estimated to be 1012-1013 cm-2. The clear detection and intriguing ring structure suggest that c-C3H2 has the potential to become a useful probe of radiation penetration in disks.

  9. Autoradiographic localization of specific (/sup 3/H)dexamethasone binding in fetal lung

    SciTech Connect

    Beer, D.G.; Butley, M.S.; Cunha, G.R.; Malkinson, A.M.

    1984-10-01

    The cellular and subcellular localization of specific (/sup 3/H)dexamethasone binding was examined in fetal mouse lung at various stages of development and in human fetal lung at 8 weeks of gestation using a rapid in vitro steroid incubation technique followed by thaw-mount autoradiography. Competition studies with unlabeled steroids demonstrate the specificity of (/sup 3/H)dexamethasone labeling, and indicate that fetal lung mesenchyme is a primary glucocorticoid target during lung development. Autoradiographs of (/sup 3/H)dexamethasone binding in lung tissue at early stages of development demonstrate that the mesenchyme directly adjacent to the more proximal portions of the bronchiolar network is heavily labeled. In contrast, the epithelium which will later differentiate into bronchi and bronchioles, is relatively unlabeled. Distal portions of the growing epithelium, destined to become alveolar ducts and alveoli, do show nuclear localization of (/sup 3/H)dexamethasone. In addition, by utilizing a technique which allows the simultaneous examination of extracellular matrix components and (/sup 3/H)dexamethasone binding, a relationship is observed between extensive mesenchymal (/sup 3/H)dexamethasone binding and extensive extracellular matrix accumulation. Since glucocorticoids stimulate the synthesis of many extracellular matrix components, these results suggest a role for these hormones in affecting mesenchymal-epithelial interactions during lung morphogenesis.

  10. Symmetry Breaking During Drosophila Oogenesis

    PubMed Central

    Roth, Siegfried; Lynch, Jeremy A.

    2009-01-01

    The orthogonal axes of Drosophila are established during oogenesis through a hierarchical series of symmetry-breaking steps, most of which can be traced back to asymmetries inherent in the architecture of the ovary. Oogenesis begins with the formation of a germline cyst of 16 cells connected by ring canals. Two of these 16 cells have four ring canals, whereas the others have fewer. The first symmetry-breaking step is the selection of one of these two cells to become the oocyte. Subsequently, the germline cyst becomes surrounded by somatic follicle cells to generate individual egg chambers. The second symmetry-breaking step is the posterior positioning of the oocyte within the egg chamber, a process mediated by adhesive interactions with a special group of somatic cells. Posterior oocyte positioning is accompanied by a par gene-dependent repolarization of the microtubule network, which establishes the posterior cortex of the oocyte. The next two steps of symmetry breaking occur during midoogenesis after the volume of the oocyte has increased about 10-fold. First, a signal from the oocyte specifies posterior follicle cells, polarizing a symmetric prepattern present within the follicular epithelium. Second, the posterior follicle cells send a signal back to the oocyte, which leads to a second repolarization of the oocyte microtubule network and the asymmetric migration of the oocyte nucleus. This process again requires the par genes. The repolarization of the microtubule network results in the transport of bicoid and oskar mRNAs, the anterior and posterior determinants, respectively, of the embryonic axis, to opposite poles of the oocyte. The asymmetric positioning of the oocyte nucleus defines a cortical region of the oocyte where gurken mRNA is localized, thus breaking the dorsal–ventral symmetry of the egg and embryo. PMID:20066085

  11. Imperfection works: Survival, transmission and persistence in the system of Heliothis virescens ascovirus 3h (HvAV-3h), Microplitis similis and Spodoptera exigua

    PubMed Central

    Li, Shun-Ji; Hopkins, Richard J.; Zhao, Yi-Pei; Zhang, Yun-Xuan; Hu, Jue; Chen, Xu-Yang; Xu, Zhi; Huang, Guo-Hua

    2016-01-01

    Ascoviruses are insect-specific large DNA viruses that mainly infect noctuid larvae, and are transmitted by parasitoids in the fields. Heliothis virescens ascovirus 3h (HvAV-3h) has been recently isolated from Spodoptera exigua, without parasitoid vector identified previously. Here we report that Microplitis similis, a solitary endoparasitoid wasp, could transmit HvAV-3h between S. exigua larvae in the laboratory. When the female parasitoid wasp acquired the virus and served as a vector, the period of virion viability on the ovipositor was 4.1 ± 1.4 days. Infected host larvae were still acceptable for egg laying by parasitoids, and the parasitoids thereafter transmitted virus to healthy hosts. Virus acquisition occurred only from donor hosts between 3 and 9 days post infection. The peak of virus acquisition (80.9 ± 6.3%) was found when M. similis wasps oviposited in larvae that had been inoculated with the virus 7 days previously. When virus infection of the host took place during the life cycle of the parasitoid wasp, it caused 1- to 4-day-old immature parasitoids death in the host, whilst a small proportion of 5- to 6-day-old and the majority of 7-day-old parasitoids larvae survived from the virus-infected hosts. Viral contamination did not reduce the life span or fecundity of female M. similis. PMID:26878829

  12. Universal Formulation For Symmetries In Computed Flows

    NASA Technical Reports Server (NTRS)

    Pao, S. Paul; Abdol-Hamid, Khaled S.

    1995-01-01

    Universal formulation for high-order symmetries in boundary conditions on flows devised. Eliminates need for special procedures to incorporate symmetries and corresponding boundary conditions into computer codes solving Navier-Stokes and Euler equations of flow.

  13. An Elementary Course in Mathematical Symmetry.

    ERIC Educational Resources Information Center

    Rose, Bruce I.; Stafford, Robert D.

    1981-01-01

    A college course designed to teach students about the mathematics of symmetry using pieces of wallpaper and cloth designs is presented. Mathematical structures and the symmetry of graphic designs provide the starting point for instruction. (MP)

  14. Characterization of [3H]LS-3-134, a Novel Arylamide Phenylpiperazine D3 Dopamine Receptor Selective Radioligand

    PubMed Central

    Rangel-Barajas, Claudia; Malik, Maninder; Taylor, Michelle; Neve, Kim A.; Mach, Robert H.; Luedtke, Robert R.

    2014-01-01

    LS-3-134 is a substituted N-phenylpiperazine derivative that has been reported to exhibit a) high-affinity binding (Ki value 0.2 nM) at human D3 dopamine receptors, b) >100-fold D3 vs. D2 dopamine receptor subtype binding selectivity and c) low-affinity binding (Ki values >5,000 nM) at sigma 1 and sigma 2 receptors. Based upon a forskolin-dependent activation of the adenylyl cyclase inhibition assay, LS-3-134 is a weak partial agonist at both D2 and D3 dopamine receptor subtypes (29% and 35% of full agonist activity, respectively). In this study, [3H]-labeled LS-3-134 was prepared and evaluated to further characterize its use as a D3 dopamine receptor selective radioligand. Kinetic and equilibrium radioligand binding studies were performed. This radioligand rapidly reaches equilibrium (10-15 min at 37°C) and binds with high affinity to both human (Kd = 0.06 ± 0.01 nM) and rat (Kd = 0.2 ± 0.02 nM) D3 receptors expressed in HEK-293 cells. Direct and competitive radioligand binding studies using rat caudate and nucleus accumbens tissue indicate that [3H]LS-3-134 selectively binds a homogeneous population of binding sites with a dopamine D3 receptor pharmacological profile. Based upon these studies we propose that [3H]LS-3-134 represents a novel D3 dopamine receptor selective radioligand that can be used for studying the expression and regulation of the D3 dopamine receptor subtype. PMID:25041389

  15. Symmetry perception in humans and macaques.

    PubMed

    Beck, Diane M; Pinsk, Mark A; Kastner, Sabine

    2005-09-01

    The human ability to detect symmetry has been a topic of interest to psychologists and philosophers since the 19th century, yet surprisingly little is known about the neural basis of symmetry perception. In a recent fMRI study, Sasaki and colleagues begin to remedy this situation. By identifying the neural structures that respond to symmetry in both humans and macaques, the authors lay the groundwork for understanding the neural mechanisms underlying symmetry perception.

  16. Flavored Peccei-Quinn symmetry

    NASA Astrophysics Data System (ADS)

    Ahn, Y. H.

    2015-03-01

    In an attempt to uncover any underlying physics in the standard model (SM), we suggest a μ - τ power law in the lepton sector, such that relatively large 13 mixing angle with bilarge ones can be derived. On the basis of this, we propose a neat and economical model for both the fermion mass hierarchy problem of the SM and a solution to the strong charge parity (C P ) problem, in a way that no domain wall problem occurs, based on A4×U (1 )X symmetry in a supersymmetric framework. Here we refer to the global U (1 )X symmetry that can explain the above problems as "flavored Peccei-Quinn symmetry." In the model, a direct coupling of the SM gauge singlet flavon fields responsible for spontaneous symmetry breaking to ordinary quarks and leptons, both of which are charged under U (1 )X, comes to pass through Yukawa interactions, and all vacuum expectation values breaking the symmetries are connected to each other. So the scale of Peccei-Quinn symmetry breaking is shown to be roughly located around the 1 012 GeV section through its connection to the fermion masses. The model predictions are shown to lie on the testable regions in the very near future through on-going experiments for neutrino oscillation, neutrinoless double beta decay, and the axion. We examine the model predictions, arisen from the μ - τ power law, on leptonic C P violation, neutrinoless double beta decay, and atmospheric mixing angle, and show that the fermion mass and mixing hierarchies are in good agreement with the present data. Interestingly, we show the model predictions on the axion mass ma≃2.53 ×1 0-5 eV and the axion coupling to photon ga γ γ≃1.33 ×1 0-15 GeV-1 . And subsequently the square of the ratio between them is shown to be one or two orders of magnitude lower than that of the conventional axion model.

  17. /sup 3/H arachidonic acid incorporation and metabolism in purified human basophils

    SciTech Connect

    Warner, J.A.; Peters, S.P.; Lichtenstein, L.M.; MacGlashan, D.W. Jr.

    1986-03-01

    A central feature of the allergic response is the generation of arachidonic acid (AA) metabolites by basophils and mast cells. In addition, AA metabolism may play a role in regulating the anti-IgE mediated degranulation of human basophils. To study this biochemistry, purified human basophils (>80%) were labeled with /sup 3/H-AA (0.3 ..mu..M, 25 ..mu..Ci/ml, 2 hours at 37/sup 0/C) and subsequently challenged with anti-IgE. Basophils were found to incorporate 45 +/- 3% of the exogenous AA which distributed into phospholipids (PL) (77.1 +/- 3.5%) and neutral lipids (19.7 +/- 3.3%) with only 5.3 +/- 2.7% remaining as the free acid (n = 7). Phosphatidylcholine (23.9 +/- 1.7%), phosphatidylinositol (22.0 +/- 1.4%) and phosphatidylethanolamine (14.5 +/- 2.7%) accounted for the majority of the AA with the remaining PL containing <3%. Anti-IgE (0.1 ..mu..g/ml) challenge led to the release of histamine (23.8 +/- 4.7%) and /sup 3/H-AA (8.1 +/- 1.7%) (n = 5). HPLC analysis revealed unmetabolized /sup 3/H-AA, /sup 3/H-LTC/sub 4/, /sup 3/H-HETE and an unidentified peak which migrated in the prostaglandin region of the elution profile. The same metabolites were released when the basophils were challenged with antigen. The calcium ionophore A23187 (1..mu..g/ml) also caused the release of histamine (37.4 +/- 4.1%) and /sup 3/H-AA (17.0 +/- 2.9%), while the phorbol ester, TPA caused HR (19.7 +/- 5.8%) but no increase in /sup 3/H AA turnover. Because of limited cell numbers this is the first time the authors have been able to study AA metabolism in human basophils.

  18. Characterization and regulation of (/sup 3/H)-serotonin uptake and release in rodent spinal

    SciTech Connect

    Stauderman, K.A.

    1986-01-01

    The uptake and release of (/sup 3/H)-serotonin were investigated in rat spinal cord synaptosomes. In the uptake experiments, sodium-dependent and sodium-independent (/sup 3/H)-serotonin accumulation processes were found. Sodium-dependent (/sup 3/H)-serotonin accumulation was: linear with sodium concentrations up to 180 mM; decreased by disruption of membrane integrity or ionic gradients; associated with purified synaptosomal fractions; and reduced after description of descending serotonergic neurons in the spinal cord. Of the uptake inhibitors tested, the most potent was fluoxetine (IC/sub 50/ 75 nM), followed by desipramine (IC/sub 50/ 430 nM) and nomifensine (IC/sub 50/ 950 nM). The sodium-independent (/sup 3/H)-serotonin accumulation process was insensitive to most treatments and probably represents nonspecific membrane binding. Thus, only sodium-dependent (/sup 3/H)-serotonin uptake represents the uptake process of serotonergic nerve terminals in rat spinal cord homogenates. In the release experiments, K/sup +/-induced release of previously accumulated (/sup 3/H)-serotonin was Ca/sup 2 +/-dependent, and originated from serotonergic synaptosomes. Exogenous serotonin and 5-methyoxy-N,N-dimethyltryptamine inhibited (/sup 3/H)-serotonin release in a concentration-dependent way. Of the antagonists tested, only methiothepin effectively blocked the effect of serotonin. These data support the existence of presynaptic serotonin autoreceptors on serotonergic nerve terminals in the rat spinal cord that act to inhibit a voltage and Ca/sup 2 +/-sensitive process linked to serotonin release. Alteration of spinai cord serotonergic function may therefore be possible by drugs acting on presynaptic serotonin autoreceptors in the spinal cord.

  19. Metabolism of D, L-/sup 3/H-norepinephrine in essential hypertension

    SciTech Connect

    Gitlow, S.; Dziedzic, S.; Dziedzic, L.; Roubein, I.

    1981-01-01

    Defective control of the cardiovascular system by the sympathetic nerves continues to be incriminated as the potential primary physiologic defect in essential hypertension (EH). The need to measure sympathetic tone has progressed from physiologic mensuration by assessment of reflex and pharmacological responses to the recent assay of norepinephrine (NE) and its congeners in both urine and plasma. The way in which the body handles D,L-B-/sup 3/H-NE represents yet another technique by which to evaluate sympathetic function. Previous studies of EH by this method demonstrated more rapid plasma disappearance of /sup 3/H-NE as well as elevated 24 hour tritium accumulation in the urine following D,L-B-/sup 3/H-NE injection. The present study of 7 normotensive subjects and 7 patients with EH was designed to depict more precisely these abnormalities in /sup 3/H-NE-metabolism. Following a one minute injection of 8 micrograms D,L-B-/sup 3/H-NE, (200 microCi) intravenously, the excretion of unlabeled endogenous metabolites and their labeled congeners was assayed. By these means one could estimate catecholamine synthesis, turnover of the labeled pools, and by comparison of relative specific activities of the metabolites, gain some insight into the distribution of the injected material. Alternative catabolic pathways were evaluated by measurement of the excretion of /sup 3/H/sub 2/O. Patients with EH excreted more label per 24 hours, revealed a more rapid decline of /sup 3/H2O excretion and lower specific activity of normetanephrine (NM). These findings are compatible with changes in pool dynamics and distribution of administered label which gave additional support to the concept of adrenergic dysfunction in association with essential hypertension.

  20. Sensitivity of early mouse embryos to (/sup 3/H)thymidine

    SciTech Connect

    Spindle, A.; Wu, K.; Pedersen, R.A.

    1982-12-01

    Effects of intranuclear radiation on the developmental capacity of early mouse embryos were studied by exposing embryos to (/sup 3/H)thymidine and counting the number of embryos forming blastocysts, trophoblast outgrowths, inner cell masses (ICMs), and two-layer ICMs (differentiated into primary endoderm and ectoderm). When embryos were cultured from the 2-cell stage for 8 days in the continuous presence of (/sup 3/H)thymidine, concentrations as low as 0.2 nCi/ml reduced the number of embryos forming two-layer ICMs. At 1 nCi/ml, the number of both ICMs and two-layer ICMs were reduced, and at 10 nCi/ml the number of embryos developing to all three post-blastocyst endpoints was reduced. Blastocyst formation was not affected even at the highst concentration (/sup 3/H)thymidine and then cultured further in unlabelled medium, the effects were similar to those of 8-day exposure. When embryos were exposed to (/sup 3/H)thymidine for 24 h at various developmental stages, effects were less severe than when they were exposed continuously for 3 or 8 days, and the sensitivity of embryos differed between stages. The 24-h exposure of immunosurgically isolated ICMS to (/sup 3/H)thymidine revealed that the high sensitivity of the ICM to (/sup 3/H)thymidine persists through the late blastocyst stage and declines progressively thereafter. Autoradiography indicated that the change in radiosensitivity of embryos or ICMs is generally related to their ability to incorporate (/sup 3/H)thymidine into the DNA.

  1. Tissue distribution of sup 3 H-nicotine in rats after bolus or constant injection

    SciTech Connect

    Chowdhury, P.; Pasley, J.N.; Rayford, P.L. )

    1989-01-01

    Two groups of rats, (N = 7), were fasted for 24 hrs prior to the study. On the day of the experiment, the animals were anesthetized and infused with either 5 ml nicotine solution (200 {mu}g/L) in saline containing 5 {mu}c {sup 3}H-nicotine, (sp. activity 50-80 mCi/mol) for 90 minutes or injected as a bolus with 0.5 ml of the same nicotine (200 {mu}g/L) solution. The animals were sacrificed 60 minutes after the injection or after the infusion was stopped. Blood and tissue samples were counted by liquid scintillation counting. Percent distribution of {sup 3}H-nicotine per gm of tissue was calculated from the total radioactivity recovered in individual tissues over the total activity injected into the rat and the values were compared using student's t test. Results: Distribution of {sup 3}H-nicotine was found highest in kidney (45-49%) among all tissues examined and was not different between routes of administration. Significantly higher retention of {sup 3}H-nicotine was found with continuous infusion in esophagus, fundus, antrum, spleen, cecum, pancreas, testes, heart and muscle when {sup 3}H-nicotine retentions were compared with bolus injection. In contrast, the distribution of {sup 3}H-nicotine in adrenal gland, was significantly lower in continuous infusion group. Distribution in blood was 6 fold higher in continuous infusion (7.26%) compared to bolus (1.11%) injection. The distribution {sup 3}H-nicotine in other tissues were not different by either routes of injection.

  2. Characterizing a sewage plume using the 3H-3He dating technique

    USGS Publications Warehouse

    Shapiro, Stephanie Dunkle; LeBlanc, Denis; Schlosser, Peter; Ludin, Andrea

    1999-01-01

    An extensive 3H-3He study was performed to determine detailed characteristics of a regional flow system and a sewage plume over a distance of 4 km in a sand and gravel aquifer at Otis Air Base in Falmouth, Massachusetts. 3H-3He ages increase with depth in individual piezometer clusters and with distance along flowpaths. However, the age gradient with depth (Δt/Δz) is smaller in the plume than that in the regional waters, due to the intense recharge in the infiltration beds. The 1960s bomb peak of tritium in precipitation is archived longitudinally along a flowline through the main axis of the plume and vertically in individual piezometer clusters. On the eastern side of the sampling area, where water from Ashumet Pond forces plume water deeper into the flow system, 3H-3He ages are young at depth because the 3H-3He "clock" is reset due to outgassing of helium in the pond. A reconstruction of the tritium input functions for the regional and plume samples shows that there is no offset in the peak [3H]+[3Hetrit] concentrations for the plume and regional water, indicating that the water from supply wells for use on the base is young. The 3H-3He ages and detergent concentrations in individual wells are consistent with the beginning of use of detergents and the time period when their concentrations in sewage would have been greatest. Ages and hydraulic properties calculated using the 3H-3He data compare well with those from previous investigations and from particle-tracking simulations.

  3. Depletion of (/sup 3/H)methyltrienolone cytosol binding in glucocorticoid-induced muscle atrophy (42001)

    SciTech Connect

    Kurowski, T.T.; Capaccio, J.A.; Chatterton, R.T. Jr.; Hickson, R.C.

    1985-01-01

    The present study was undertaken to determine cytosol binding properties of (/sup 3/H)methyltrienolone, a synthetic androgen, in comparison with (/sup 3/)dexamethasone, a synthetic glucocorticoid, under conditions of glucocorticoid excess in skeletal muscle. Male hypophysectomized rats received either seven daily subcutaneous injections of cortisone acetate (CA) (100 mg x kg/sup -1/ body wt) or the vehicle, 1% carboxymethyl cellulose. Following treatment, both (/sup 3/H)dexamethansone and (/sup 3/H)methyltrienolone-receptor concentrations were decreased from those in vehicle-treated rats by more than 90 and 80%, respectively, in CA-treated animals. Scatchard analysis of (/sup 3/H)methyltrienolone binding in muscles of vehicle-treated animals became nonlinear at high concentrations of labeled ligand and were reanalyzed by a two-component binding model. The lower affinity, higher capacity component, which was attributed to binding of methyltrienolone to a dexamethasone component, which was attributed to binding of methyltrienolone to a dexamethasone component, disappeared in muscles of CA-treated rats and Scatchard plots were linear. Receptor concentrations of the higher affinity lower capacity methyltrienolone component were similar in muscles of vehicle-treated and CA-treated groups. From competition studies, the high relative specificities of glucocorticoids for (/sup 3/H)methyltrienolone binding in muscles of vehicle-treated animals were markedly reduced by CA treatment. In addition, the binding specificity data also showed strong competition by progesterone and methyltrienolone for (/sup 3/H)dexamethasone binding and estradiol-17..beta.. for (/sup 3/H)methyltrienolone binding.

  4. Metabolism studies of unformulated internally [3H]-labeled short interfering RNAs in mice.

    PubMed

    Christensen, Jesper; Litherland, Karine; Faller, Thomas; van de Kerkhof, Esther; Natt, François; Hunziker, Jürg; Krauser, Joel; Swart, Piet

    2013-06-01

    Absorption, distribution, metabolism, and excretion properties of two unformulated model short interfering RNA (siRNAs) were determined using a single internal [(3)H]-radiolabeling procedure, in which the full-length oligonucleotides were radiolabeled by Br/(3)H -exchange. Tissue distribution, excretion, and mass balance of radioactivity were investigated in male CD-1 mice after a single intravenous administration of the [(3)H]siRNAs, at a target dose level of 5 mg/kg. Quantitative whole-body autoradiography and liquid scintillation counting techniques were used to determine tissue distribution. Radiochromatogram profiles were determined in plasma, tissue extracts, and urine. Metabolites were separated by liquid chromatography and identified by radiodetection and high-resolution accurate mass spectrometry. In general, there was little difference in the distribution of total radiolabeled components after administration of the two unformulated [(3)H]siRNAs. The radioactivity was rapidly and widely distributed throughout the body and remained detectable in all tissues investigated at later time points (24 and 48 hours for [(3)H]MRP4 (multidrug resistance protein isoform 4) and [(3)H]SSB (Sjögren Syndrome antigen B) siRNA, respectively). After an initial rapid decrease, concentrations of total radiolabeled components in dried blood decreased at a much slower rate. A nearly complete mass balance was obtained for the [(3)H]SSB siRNA, and renal excretion was the main route of elimination (38%). The metabolism of the two model siRNAs was rapid and extensive. Five minutes after administration, no parent compound could be detected in plasma. Instead, radiolabeled nucleosides resulting from nuclease hydrolysis were observed. In the metabolism profiles obtained from various tissues, only radiolabeled nucleosides were found, suggesting that siRNAs are rapidly metabolized and that the distribution pattern of total radiolabeled components can be ascribed to small molecular

  5. Generalized partial dynamical symmetry in nuclei.

    PubMed

    Leviatan, A; Isacker, P Van

    2002-11-25

    We introduce the notion of a generalized partial dynamical-symmetry for which part of the eigenstates have part of the dynamical symmetry. This general concept is illustrated with the example of Hamiltonians with a partial dynamical O(6) symmetry in the framework of the interacting boson model. The resulting spectrum and electromagnetic transitions are compared with empirical data in 162Dy.

  6. Noether symmetries and duality transformations in cosmology

    NASA Astrophysics Data System (ADS)

    Paliathanasis, Andronikos; Capozziello, Salvatore

    2016-09-01

    We discuss the relation between Noether (point) symmetries and discrete symmetries for a class of minisuperspace cosmological models. We show that when a Noether symmetry exists for the gravitational Lagrangian, then there exists a coordinate system in which a reversal symmetry exists. Moreover, as far as concerns, the scale-factor duality symmetry of the dilaton field, we show that it is related to the existence of a Noether symmetry for the field equations, and the reversal symmetry in the normal coordinates of the symmetry vector becomes scale-factor duality symmetry in the original coordinates. In particular, the same point symmetry as also the same reversal symmetry exists for the Brans-Dicke scalar field with linear potential while now the discrete symmetry in the original coordinates of the system depends on the Brans-Dicke parameter and it is a scale-factor duality when ωBD = 1. Furthermore, in the context of the O’Hanlon theory for f(R)-gravity, it is possible to show how a duality transformation in the minisuperspace can be used to relate different gravitational models.

  7. Superalgebra and fermion-boson symmetry

    PubMed Central

    Miyazawa, Hironari

    2010-01-01

    Fermions and bosons are quite different kinds of particles, but it is possible to unify them in a supermultiplet, by introducing a new mathematical scheme called superalgebra. In this article we discuss the development of the concept of symmetry, starting from the rotational symmetry and finally arriving at this fermion-boson (FB) symmetry. PMID:20228617

  8. Symmetry Breaking for Black-Scholes Equations

    NASA Astrophysics Data System (ADS)

    Yang, Xuan-Liu; Zhang, Shun-Li; Qu, Chang-Zheng

    2007-06-01

    Black-Scholes equation is used to model stock option pricing. In this paper, optimal systems with one to four parameters of Lie point symmetries for Black-Scholes equation and its extension are obtained. Their symmetry breaking interaction associated with the optimal systems is also studied. As a result, symmetry reductions and corresponding solutions for the resulting equations are obtained.

  9. Specific [3H]raclopride binding to neostriatal dopamine D2 receptors: role of disulfide and sulfhydryl groups.

    PubMed

    Reader, T A; Molina-Holgado, E; Lima, L; Boulianne, S; Dewar, K M

    1992-08-01

    Receptor binding studies were performed in rabbit neostriatum (caudate-putamen) using the dopamine D2 antagonist [3H]raclopride. Treatment of the membrane preparations with the reducing agent L-dithiothreitol (L-DTT) as well as with the alkylating compound N-ethylmaleimide (NEM), produced dose-dependent decreases of specific [3H]raclopride binding; the IC50 values were of 3.1 and 1.2 mM, respectively. Saturation experiments showed that the reduction of disulfide (-S-S-) bonds by L-DTT (1 mM) decreased the number of binding sites, with only a slight increase in the affinity. On the other hand, alkylation of sulfhydryl (-SH) groups by NEM (1 mM) decreased both receptor number and affinity. The properties of the remaining binding sites were examined in competition curves with the physiological substrate dopamine and the dopaminergic antagonist (+)butaclamol. The IC50 values for (+)butaclamol in control and in L-DTT and NEM treated membranes were between 3.4 and 4.8 nM, with Hill coefficients (nH) of 1, indicating that the remaining binding sites conserved a high affinity for antagonist binding. In the case of dopamine, the curves were shallow (nH 0.45-0.64) and both compounds increased the IC50 from 0.7 microM (control) to 8 microM and 11 microM, for L-DTT and NEM respectively. Iterative analysis revealed that L-DTT produced a very important (greater than 60%) decrease in the number of high-affinity (RH) binding. After NEM, there was a decrease in both the number of (RH) and the affinity (KH) of the high-affinity binding sites, and in the affinity (KL) of the low-affinity sites. These results demonstrate the participation of -S-S- and -SH groups in the agonist conformation of the primary ligand recognition site of the dopamine D2 receptor. Alternatively, -S-S- and -SH groups could be related to the coupling of the primary ligand recognition protein with adenylate cyclase by means of an inhibitory type of G protein.

  10. Pharmacological specificity of some psychotomimetic and antipsychotic agents for the sigma and PCP binding sites

    SciTech Connect

    Itzhak, Y.

    1988-01-01

    The pharmacological specificity of representative psychotomimetic agents such a phencyclidine (PCP) analogs, opiate benzomorphans and several antipsychotic agents was assessed for the sigma and PCP binding sites. In a series of binding experiments, in rat brain membranes, sigma and PCP binding sites were labeled with (/sup 3/H)-1-(1-(3-hydroxyphenyl) cyclohexyl) piperidine ((/sup 3/H)PCP-3-OH), (+)(/sup 3/H)-N-allylnormetazocine ((+)(/sup 3/H)SKF 10047) and (+) (/sup 3/H)-3-(3-hydroxy-phenyl)-N-(1-propyl) piperidine and ((+)(/sup 3/H)-3-PPP). PCP analogs inhibit potently high affinity (/sup 3/H)PCP-3-OH binding and (+)(/sup 3/H)SKF 10047 binding, moderately the low affinity binding component of (/sup 3/H)PCP-3-OH and very weakly (+) (/sup 3/H)-3-PPP binding. (+)SKF 10047 and cyclazocine are potent to moderate inhibitors of (+)(/sup 3/H)SKF 10047, high affinity (/sup 3/H)PCP-3-OH and (+)(/sup 3/H)-3-PCP-3-OH binding. The antipsychotic agents display high affinity for (+)(/sup 3/H)-3-PPP binding sites, moderate affinity for (+)(/sup 3/H)SKF 10047 sites and have no effect on either the high or low affinity (/sup 3/H)PCP-3-OH binding. 20 references, 3 figures, 2 tables.

  11. Effect of the alkaloid (-)cathinone on the release of radioactivity from rabbit atria prelabelled with /sup 3/H-norepinephrine

    SciTech Connect

    Kalix, P.

    1983-02-14

    In certain countries of East Africa and the Arab Peninsula, fresh leaves of the khat shrub are used as a stimulant. The effect of the plant material can be explained by the presence of the phenylalklamine alkaloid (-)cathinone in the leaves, since this substance has been shown to have an amphetamine-like releasing effect on CNS tissue prelabelled with /sup 3/H-dopamine. Characteristically, the chewing of khat is accompanied by sympathomimetic effects, especially at the cardiovascular level. To test whether these might be due to release of neurotransmitter from adrenergic nerve endings, the effect of (-)cathinone on the efflux of radioactivity from isolated rabbit atrium tissue prelabelled with /sup 3/H-norepinephrine was investigated. It was found that, at concentrations below 1 ..mu..M, (-)cathinone caused an immediate increase of efflux. The effect was dose-dependent and was potentiated by pretreatment of the rabbits with reserpine. Preincubation of the tissue with desipramine and cocaine prevented the induction of release by (-)cathinone. The results indicate that the alkaloid (-)cathinone has an amphetamine-like releasing effect on noradrenergic nerve endings and they suggest that the cardiovascular symptoms observed during khat consumption are due to release of neurotransmitter from physiologicl storage sites.

  12. Binding of (/sup 3/H)isradipine (PN 200-110) on smooth muscle cell membranes from different bovine arteries

    SciTech Connect

    Pinquier, J.L.; Urien, S.; Chaumet-Riffaud, P.; Comte, A.; Tillement, J.P.

    1988-04-01

    The binding of (/sup 3/H)isradipine ((/sup 3/H)PN 200-110), a new dihydropyridine (DHP) calcium blocker on smooth muscle cell (SMC) membranes from different bovine arteries was saturable with comparable high affinities but different binding site densities (Bmax). The data were fitted to a model that provided a common estimation for the dissociation constant (Kd = 0.46 nM, SD = 0.03) but different Bmax values. Two groups of arteries could be distinguished, large-sized with high Bmax (aorta, 149 fmol/mg, SD = 4; intrapulmonary, 134 fmol/mg, SD = 4) and medium-sized with lower Bmax (mesenteric, 67 fmol/mg, SD = 2; internal carotid, 50 fmol/mg, SD = 2; renal artery, 29 fmol/mg, SD = 2). The Kd values were similar to those previously reported, but the Bmax value on aorta SMC was higher than usually reported with other DHPs, showing that isradipine was a high full antagonist of calcium channel. Our results also suggest that the increase in arterial compliance induced by DHPs will probably be more important on large-sized arteries than on medium-sized arteries because of higher DHP binding.

  13. CP symmetry in optical systems

    NASA Astrophysics Data System (ADS)

    Dana, Brenda; Bahabad, Alon; Malomed, Boris A.

    2015-04-01

    We introduce a model of a dual-core optical waveguide with opposite signs of the group-velocity dispersion in the two cores, and a phase-velocity mismatch between them. The coupler is embedded into an active host medium, which provides for the linear coupling of a gain-loss type between the two cores. The same system can be derived, without phenomenological assumptions, by considering the three-wave propagation in a medium with the quadratic nonlinearity, provided that the depletion of the second-harmonic pump is negligible. This linear system offers an optical realization of the charge-parity symmetry, while the addition of the intracore cubic nonlinearity breaks the symmetry. By means of direct simulations and analytical approximations, it is demonstrated that the linear system generates expanding Gaussian states, while the nonlinear one gives rise to broad oscillating solitons, as well as a general family of stable stationary gap solitons.

  14. Facial symmetry in robust anthropometrics.

    PubMed

    Kalina, Jan

    2012-05-01

    Image analysis methods commonly used in forensic anthropology do not have desirable robustness properties, which can be ensured by robust statistical methods. In this paper, the face localization in images is carried out by detecting symmetric areas in the images. Symmetry is measured between two neighboring rectangular areas in the images using a new robust correlation coefficient, which down-weights regions in the face violating the symmetry. Raw images of faces without usual preliminary transformations are considered. The robust correlation coefficient based on the least weighted squares regression yields very promising results also in the localization of such faces, which are not entirely symmetric. Standard methods of statistical machine learning are applied for comparison. The robust correlation analysis can be applicable to other problems of forensic anthropology.

  15. Symmetry breaking around a wormhole

    NASA Astrophysics Data System (ADS)

    Choudhury, A. L.

    1996-11-01

    We have modified the extended version Coule and Maeda's version (D. H. Coule and Kei-ichi Maeda, Class.Quant.Grav.7,995(1990)) of the Gidding-Strominger model (S. B. Giddings and A. Strominger, Nucl.Phys. B307, 854(l988)) of the euclidean gravitational field interacting with axion. The new model has R-symmetry in contrast to the previous model. At the lowest perturbation case the model retains a wormhole solution. We assume that the scalar expands adiabatically and satisfies ideal gas law in a crude first approximation. Under the Higg's mechanism the symmetry can be broken at the tree approximation. This mechanism, we hope, can be used to introduce the degeneracy of quark masses.

  16. Broken symmetries in multilayered perceptrons

    NASA Astrophysics Data System (ADS)

    Barkai, E.; Hansel, D.; Sompolinsky, H.

    1992-03-01

    The statistical mechanics of two-layered perceptrons with N input units, K hidden units, and a single output unit that makes a decision based on a majority rule (Committee Machine) are studied. Two architectures are considered. In the nonoverlapping case the hidden units do not share common inputs. In the fully connected case each hidden unit is connected to the entire input layer. In both cases the network realizes a random dichotomy of P inputs. The statistical properties of the space of solutions as a function of P is studied, using the replica method, and by numerical simulations, in the regime where N>>K. In the nonoverlapping architecture with continuously varying weights the capacity, defined as the maximal number of P per weight, (αc) is calculated under a replica-symmetric (RS) ansatz. At large K, αc diverges as K1/2 in contradiction with the rigorous upper bound, αcsymmetry-breaking effect. The instability of the RS solution is shown to occur at a value of α which remains finite in the large-K limit. A one-step replica-symmetry-breaking (RSB) ansatz is studied for K=3 and in the limit K goes to infinity. The results indicate that αc(K) diverges with K, probably logarithmically. The occurrence of RSB far below the capacity limit is confirmed by comparison of the theoretical results with numerical simulations for K=3. This symmetry breaking implies that unlike the single-layer perceptron case, the space of solutions of the two-layer perceptron breaks, beyond a critical value of α, into many disjoint subregions. The entropies of the connected subregions are almost degenerate, their relative difference being of order 1/N. In the case of a nonoverlapping Committee Machine with binary, i.e., +/-1 weights, αc<=1 is an upper bound for all K. The RS theory predicts αc=0.92 for K=3 and αc=0.95 for the large-K limit

  17. Symmetry of cardiac function assessment

    PubMed Central

    Bai, Xu-Fang; Ma, Amy X

    2016-01-01

    Both right and left ventricles are developed from two adjacent segments of the primary heart tube. Though they are different with regard to shape and power, they mirror each other in terms of behavior. This is the first level of symmetry in cardiac function assessment. Both cardiac muscle contraction and relaxation are active. This constructs the second level of symmetry in cardiac function assessment. Combination of the two levels will help to find some hidden indexes or approaches to evaluate cardiac function. In this article, four major indexes from echocardiography were analyzed under this principal, another seventeen indexes or measurement approaches came out of the shadow, which is very helpful in the assessment of cardiac function, especially for the right cardiac function and diastolic cardiac function. PMID:27582768

  18. Mg6.75(OH)3(H0.166AsO4)3(HAsO4), a member of the M 1- xM′6(OH)3(H2x/3AsO4)3(HAsO4) family (M,M′ = Co; Ni)

    PubMed Central

    Weil, Matthias

    2013-01-01

    In the structure of the title compound, magnesium hydroxide hydrogenarsenate (6.75/3/4), two different Mg2+ ions, one located on a site with symmetry 3m. (occupancy 3/4) and one on a general position, as well as two different AsO3(OH) tetra­hedra (symmetry .m. with partial occupancy for the H atom for one, and symmetry 3m. with full occupancy for the H atom for the other) and one OH− ion (site symmetry .m.) are present. Both Mg2+ ions are octa­hedrally surrounded by O atoms. The MgO6 octa­hedra belonging to the partially occupied Mg2+ sites share faces, forming chains along [001]. The other type of MgO6 octa­hedra share corners and faces under formation of strands parallel to [001] whereby individual strands are linked through common corner atoms. The two types of AsO3(OH) tetra­hedra inter­link the strands and the chains, building up a three-dimensional framework resembling that of the mineral dumortierite. The OH groups were assigned on basis of bond-valence calculations and crystal chemical considerations. PMID:23723752

  19. Effect of peroxides on [3H]D-aspartate release from bovine isolated retinae.

    PubMed

    LeDay, Angela M; Awe, Sunday O; Kulkarni, Kaustubh; Harris, Lydia C; Opere, Catherine; Dash, Alekha; Ohia, Sunny E

    2004-04-01

    In the present study, we investigated the effect of naturally occurring and synthetic peroxides on K+-depolarization-evoked release of [3H]D-aspartate from bovine isolated retinae. Furthermore, effect of peroxides on endogenous glutamate concentrations were measured by HPLC in bovine neural retinae and vitreous humor of eyes treated with hydrogen peroxide (H2O2) ex vivo. Both naturally occurring H2O2 (1-100 microM) and synthetic (cumene hydroperoxide, cuOOH; 1-100 microM) peroxides caused a concentration-dependent inhibition of K+-evoked [3H]D-aspartate release without affecting basal tritium efflux. The antioxidant, trolox (2 mM) prevented the inhibition of evoked [3H]D-aspartate overflow elicited by both H2O2 (30 microM) and cuOOH (10 microM). Inhibition of catalase by 3-amino-triazole (3- AT 100 mM) enhanced an inhibitory effect of a low concentration of H2O2 (1 microM) but antagonized the effect of H2O2 (30 microM) on K+-induced [3H]D-aspartate release. In ex vivo experiments, exogenously applied H2O2 (1-100 microM) also caused a concentration-related decrease in glutamate levels in the bovine retina. We conclude that peroxides can inhibit K+-evoked release of [3H]D-aspartate and also decrease endogenous glutamate concentrations in the bovine retina.

  20. [[sup 3]H]QNB displays in vivo selectivity for the m2 subtype

    SciTech Connect

    Gitler, M.S.; De La Cruz, R.; Zeeberg, B.R. ); Reba, R.C. Univ. of Chicago Hospital, Chicago, IL )

    1994-01-01

    Alzheimer's disease (AD) involves selective loss of muscarinic m2, but not m1, subtype neuroreceptors in the posterior parietal cortex of the human brain. Emission tomographic study of the loss of m2 receptors in AD is limited by the fact that there is currently no available m2-selective radioligand which can penetrate the blood-brain barrier. [[sup 3]H](R)-3-quinuclidinylbenzilate ([[sup 3]H]QNB) is commonly used for performing in vitro studies of the muscarinic acetylcholine receptor (mAChR), either with membrane homogenates or with autoradiographic slices, in which [[sup 3]H]QNB is nonsubtype-selective. We report here the results of in vivo studies, using both carrier-free and low specific activity [[sup 3]H]QNB, which show that [[sup 3]H]QNB exhibits a substantial in vivo m2-selectivity. Previously reported in vivo (R)-3-quinuclidinyl (R)-4-iodobenzilate ((R,R)-[[sup 125]I]lQNB) binding appears to be nonsubtype-selective. Apparently the bulky iodine substitution in the 4 position reduces the subtype selectivity of QNB. It is possible that a less bulky fluorine substitution might permit retention of the selectivity exhibited by QNB itself. We conclude that a suitably radiolabeled derivative of QNB, possibly labeled with [sup 18]F, may be of potential use in positron emission tomographic (PET) study of the loss of m2 receptors in AD. 39 refs., 8 figs., 2 tab.

  1. Immunogenicity and protective efficacy of DMT liposome-adjuvanted tuberculosis subunit CTT3H vaccine.

    PubMed

    Teng, Xindong; Tian, Maopeng; Li, Jianrong; Tan, Songwei; Yuan, Xuefeng; Yu, Qi; Jing, Yukai; Zhang, Zhiping; Yue, Tingting; Zhou, Lei; Fan, Xionglin

    2015-01-01

    Different strategies have been proposed for the development of protein subunit vaccine candidates for tuberculosis (TB), which shows better safety than other types of candidates and the currently used Bacillus Calmette-Guérin (BCG) vaccine. In order to develop more effective protein subunits depending on the mechanism of cell-mediated immunity against TB, a polyprotein CTT3H, based on 5 immunodominant antigens (CFP10, TB10.4, TB8.4, Rv3615c, and HBHA) with CD8(+) epitopes of Mycobacterium tuberculosis, was constructed in this study. We vaccinated C57BL/6 mice with a TB subunit CTT3H protein in an adjuvant of dimethyldioctadecylammonium/monophosphoryl lipid A/trehalose 6,6'-dibehenate (DDA/MPL/TDB, DMT) liposome to investigate the immunogenicity and protective efficacy of this novel vaccine. Our results demonstrated that DMT liposome-adjuvanted CTT3H vaccine not only induced an antigen-specific CD4(+) Th1 response, but also raised the number of PPD- and CTT3H-specific IFN-γ(+) CD8(+) T cells and elicited strong CTL responses against TB10.4, which provided more effective protection against a 60 CFU M. tuberculosis aerosol challenge than PBS control and DMT adjuvant alone. Our findings indicate that DMT-liposome is an effective adjuvant to stimulate CD8(+) T cell responses and the DMT-adjuvanted subunit CTT3H vaccine is a promising candidate for the next generation of TB vaccine.

  2. In vivo benzodiazepine receptor binding and imaging using (/sup 3/H)-flunitrazepam

    SciTech Connect

    Ciliax, B.J.

    1987-01-01

    The use of (/sup 3/H)-flunitrazepam as a ligand to image and measure alterations in benzodiazepine receptors in vivo in rat was investigated. Animals were injected with (/sup 3/H)-flunitrazepam intravenously, arterial samples of (/sup 3/H)-flunitrazepam were obtained and later the animals were sacrificed to assay brain binding. (/sup 3/H)-Flunitrazepam entered brain rapidly and bound to benzodiazepine receptors. A series of rats were lesioned unilaterally with kainic acid in the caudate-putamen several months prior to the infusion of (/sup 3/H)-flunitrazepam. In vivo autoradiography in lesioned rats showed that benzodiazepine binding in the lesioned striatum was significantly decreased compared to the control side and that benzodiazepine binding in globus pallidus and substantia nigra on the side of the lesion was significantly increased as compared to the intact side. The observed changes in benzodiazepine binding were similar to those observed previously in lesioned rats using in vitro techniques. Thus, benzodiazepine receptor regulation could be imaged quantitatively using in vivo binding techniques.

  3. In vivo (/sup 3/H)flunitrazepam binding: imaging of receptor regulation

    SciTech Connect

    Ciliax, B.J.; Penney, J.B. Jr.; Young, A.B.

    1986-08-01

    The use of (/sup 3/H)flunitrazepam as a ligand to measure alterations in benzodiazepine receptors in vivo in rats was investigated. Animals were injected with (/sup 3/H)flunitrazepam i.v., arterial samples of (/sup 3/H)flunitrazepam were obtained and, later, the animals were sacrificed to assay brain binding. (/sup 3/H)flunitrazepam enters the brain rapidly and binds to benzodiazepine receptors. About two-thirds of this binding is blocked by predosing the animals with 5 mg/kg of clonazepam. The amount of remaining (nonspecific) binding correlates very well (r = 0.88) with the amount of radioactivity found in plasma at the time of death. A series of rats were lesioned unilaterally with kainic acid in the caudate-putamen several months before the infusion of (/sup 3/H)flunitrazepam. In vivo autoradiography in lesioned rats showed that benzodiazepine binding in globus pallidus and substantia nigra on the side of the lesion was increased significantly as compared to the intact side. The observed changes in benzodiazepine binding were similar to those observed previously in lesioned rats using in vitro techniques. Thus, benzodiazepine receptor regulation can be imaged quantitatively using in vivo binding techniques.

  4. Pharmacokinetics and autoradiography of [3H] or [14C]stepholidine.

    PubMed

    Zhang, Z D; Zhou, C M; Jin, G Z; Zhang, X; Yang, L

    1990-07-01

    After iv [3H]stepholidine (SPD) 12 MBq/kg, the concentration-time curve in rats was found to be a two-compartment open model. The distribution phase T1/2 alpha = 3.6 min, the elimination phase T1/2 beta = 168 min. The absorbed radioactivities of [3H] SPD in 15-30 min were 80-87%. The amounts of [3H]SPD bound to plasma protein, liver and kidney homogenates were estimated to be 37, 31, and 30%, respectively. During 3 d after ip [3H]SPD 50 MBq/kg, 56% of the radioactivity was excreted in urine and 5% in feces, thus, it suggested that [3H]SPD was mainly excreted by kidneys. After iv a single dose of [14C]SPD in mice, the whole-body autoradiography showed that [14C]SPD was rapidly distributed among various tissues. High radioactivities were found in kidneys, liver, brain, salivary glands, Harder's glands, heart blood and muscle at 2 min and intensively localized in kidneys and stomach mucosa at 30 min. The radioactivities in these tissues disappeared 4 and 8 h later, while that in intestine could not be detected 24 h later.

  5. Enkephalin convertase: Characterization and localization with ( sup 3 H)-guanidinoethylmercap-tosuccinic acid

    SciTech Connect

    Lynch, D.R.

    1988-01-01

    Enkephalin convertase (EC) has been characterized by the binding of its selective inhibitor ({sup 3}H)-guanidinoethylmercaptosuccinic acid (GEMSA). The pharmacology and affinity of ({sup 3}H)-GEMSA binding match the pharmacology of EC activity and the inhibition of EC activity by GEMSA. EC activity and ({sup 3}H)-GEMSA binding activity copurify to homogeneity demonstrating that ({sup 3}H)-GEMSA binds selectively to EC. The selective association of ({sup 3}H)-GEMSA for EC allows localization of membrane bound EC by in vitro autoradiography. EC is heterogeneously distributed in the rat brain with the highest levels in the outer zone of the median eminence and in the hypothalamic magnocellular nuclei. In the pituitary gland, autoradiography localizes EC to all three lobes with the highest levels in the intermediate lobe. In the adrenal EC is found exclusively in the medulla. In the gastrointestinal tract, EC is localized to epithelial surfaces where its function cannot be that of propeptide processing. In the heart EC is localized to atrium where it likely processes precursors of atrial natriuretic factor.

  6. Symmetries in Lagrangian Field Theory

    NASA Astrophysics Data System (ADS)

    Búa, Lucia; Bucataru, Ioan; León, Manuel de; Salgado, Modesto; Vilariño, Silvia

    2015-06-01

    By generalising the cosymplectic setting for time-dependent Lagrangian mechanics, we propose a geometric framework for the Lagrangian formulation of classical field theories with a Lagrangian depending on the independent variables. For that purpose we consider the first-order jet bundles J1π of a fiber bundle π : E → ℝk where ℝk is the space of independent variables. Generalized symmetries of the Lagrangian are introduced and the corresponding Noether theorem is proved.

  7. Fermion mass without symmetry breaking

    NASA Astrophysics Data System (ADS)

    Catterall, Simon

    2016-01-01

    We examine a model of reduced staggered fermions in three dimensions interacting through an SO (4) invariant four fermion interaction. The model is similar to that considered in a recent paper by Ayyer and Chandrasekharan [1]. We present theoretical arguments and numerical evidence which support the idea that the system develops a mass gap for sufficiently strong four fermi coupling without producing a symmetry breaking fermion bilinear condensate. Massless and massive phases appear to be separated by a continuous phase transition.

  8. Explaining quantum spontaneous symmetry breaking

    NASA Astrophysics Data System (ADS)

    Liu, Chuang; Emch, Gérard G.

    Two accounts of quantum symmetry breaking (SSB) in the algebraic approach are compared: the representational and the decompositional account. The latter account is argued to be superior for understanding quantum SSB. Two exactly solvable models are given as applications of our account: the Weiss-Heisenberg model for ferromagnetism and the BCS model for superconductivity. Finally, the decompositional account is shown to be more conducive to the causal explanation of quantum SSB.

  9. Three-component Laser Doppler Anemometer for Gas Flowrate Measurements up to 5 500 m3/h

    NASA Astrophysics Data System (ADS)

    Dopheide, D.; Strunck, V.; Krey, E.-A.

    1994-01-01

    In the Physikalisch-Technische Bundesanstalt (PTB) the primary standard for on-line flowrate measurements using the laser Doppler anemometer (LDA) technique has been extended to a three-component LDA to improve velocity profile measurements in the boundary layers of a nozzle flow. The LDA flowrate measuring facility now consists of a two-colour argon ion LDA and a wavelength-stabilized GaAlAs diode laser LDA. The gas flowrate is obtained by numerical integration of the measured velocity profiles across the exit plane of the nozzle. High local resolution of the velocity profile measurements is achieved by perpendicular orientation of the measurement volumes of the two-component gas laser LDA and the semiconductor diode laser LDA (LD-LDA). This allows the resolution in the boundary layer to be improved significantly to velocity gradients. The present work presents the LD-LDA system for precise velocity profile measurements at flow velocities of up to 120 m/s; selected profile measurements are described in detail to demonstrate the high resolution and the symmetry of the flow profile. For the first time a wavelength-stabilized miniaturized diode laser LDA has been successfully applied in precise velocity measurements, and comparisons with well-established gas laser LDAs have been made. The uncertainty of the flowrate measurement up to 5 500 m3/h is 0,1% for air at atmospheric pressure. A turbine gas meter, type Elster G2500, was calibrated with the LDA and used as a transfer standard for an intercomparison with the Nederlands Meetinstituut (NMI) in the flowrate range up to 5 500 m3/h with and without the installation of perforated plates to condition the flow in the inlet section of the gas meter. The results of the comparison experiment clearly show the reliability and accuracy of the online flowrate measurement of gases and underline the necessity for a detailed research programme to investigate the relationship between installation effects, upstream flow conditions

  10. Dark matter and global symmetries

    NASA Astrophysics Data System (ADS)

    Mambrini, Yann; Profumo, Stefano; Queiroz, Farinaldo S.

    2016-09-01

    General considerations in general relativity and quantum mechanics are known to potentially rule out continuous global symmetries in the context of any consistent theory of quantum gravity. Assuming the validity of such considerations, we derive stringent bounds from gamma-ray, X-ray, cosmic-ray, neutrino, and CMB data on models that invoke global symmetries to stabilize the dark matter particle. We compute up-to-date, robust model-independent limits on the dark matter lifetime for a variety of Planck-scale suppressed dimension-five effective operators. We then specialize our analysis and apply our bounds to specific models including the Two-Higgs-Doublet, Left-Right, Singlet Fermionic, Zee-Babu, 3-3-1 and Radiative See-Saw models. Assuming that (i) global symmetries are broken at the Planck scale, that (ii) the non-renormalizable operators mediating dark matter decay have O (1) couplings, that (iii) the dark matter is a singlet field, and that (iv) the dark matter density distribution is well described by a NFW profile, we are able to rule out fermionic, vector, and scalar dark matter candidates across a broad mass range (keV-TeV), including the WIMP regime.

  11. Symmetry analysis of talus bone

    PubMed Central

    Islam, K.; Dobbe, A.; Komeili, A.; Duke, K.; El-Rich, M.; Dhillon, S.; Adeeb, S.; Jomha, N. M.

    2014-01-01

    Objective The main object of this study was to use a geometric morphometric approach to quantify the left-right symmetry of talus bones. Methods Analysis was carried out using CT scan images of 11 pairs of intact tali. Two important geometric parameters, volume and surface area, were quantified for left and right talus bones. The geometric shape variations between the right and left talus bones were also measured using deviation analysis. Furthermore, location of asymmetry in the geometric shapes were identified. Results Numerical results showed that talus bones are bilaterally symmetrical in nature, and the difference between the surface area of the left and right talus bones was less than 7.5%. Similarly, the difference in the volume of both bones was less than 7.5%. Results of the three-dimensional (3D) deviation analyses demonstrated the mean deviation between left and right talus bones were in the range of -0.74 mm to 0.62 mm. It was observed that in eight of 11 subjects, the deviation in symmetry occurred in regions that are clinically less important during talus surgery. Conclusions We conclude that left and right talus bones of intact human ankle joints show a strong degree of symmetry. The results of this study may have significance with respect to talus surgery, and in investigating traumatic talus injury where the geometric shape of the contralateral talus can be used as control. Cite this article: Bone Joint Res 2014;3:139–45. PMID:24802391

  12. Theoretical temperature-dependent branching ratios and laser thresholds of the 3F4 to 3H6 levels of Tm(3+) in ten garnets

    NASA Technical Reports Server (NTRS)

    Filer, Elizabeth D.; Barnes, Norman P.; Morrison, Clyde A.

    1991-01-01

    The calculated energy levels, the branching ratios, and the estimated thresholds for thulium operating on the 3F4 to 3H6 transitions are reported. Garnet materials with the general formula A3B2C3O12 are evaluated. Calculations are performed for the A side under the assumption of D2 symmetry. X-ray data available in the literature are used to evaluate the crystal-field components, A sub nm. Even-n components are employed to calculate the crystal-field splittings within the manifold. Thermal occupation factors are determined in a straightforward manner using a Boltzmann distribution for the respective manifolds. Odd-n components are applied to calculate the transition probabilities for electric field transitions. It is determined that the magnetic dipole contributions to the transition probability are comparable to the electric dipole contributions in some cases. Thresholds as a function of the density of thulium atoms are calculated.

  13. The molecular structure of the phosphate mineral senegalite Al2(PO4)(OH)3ṡ3H2O - A vibrational spectroscopic study

    NASA Astrophysics Data System (ADS)

    Frost, Ray L.; López, Andrés; Xi, Yunfei; Murta, Natália; Scholz, Ricardo

    2013-09-01

    We have studied the mineral senagalite, a hydrated hydroxy phosphate of aluminium with formula Al2(PO4)(OH)3ṡ3H2O using a combination of electron microscopy and vibrational spectroscopy. Senegalite crystal aggregates shows tabular to prismatic habitus and orthorhombic form. The Raman spectrum is dominated by an intense band at 1029 cm-1 assigned to the PO43- ν1 symmetric stretching mode. Intense Raman bands are found at 1071 and 1154 cm-1 with bands of lesser intensity at 1110, 1179 and 1206 cm-1 and are attributed to the PO43- ν3 antisymmetric stretching vibrations. The infrared spectrum shows complexity with a series overlapping bands. A comparison is made with spectra of other aluminium containing phosphate minerals such as augelite and turquoise. Multiple bands are observed for the phosphate bending modes giving support for the reduction of symmetry of the phosphate anion. Vibrational spectroscopy offers a means for the assessment of the structure of senagalite.

  14. Enhanced striatial /sup 3/H-spiroperidol binding induced by chronic haloperidol treatment inhibited by peptides administered during the withdrawal phase

    SciTech Connect

    Bhargava, H.N.

    1984-02-27

    Chronic intragastric administration of haloperidol (1.5 mg/kg/day) for 21 days followed by a 3-day withdrawal period resulted in the development of enhanced locomotor activity response to apomorphine, and an increase in the number of binding sites for /sup 3/H-spiroperidol in the striatal membranes of the rat brain. Subcutaneous administration of Pro-Leu-Gly-NH/sub 2/ or cyclo-(Leu-Gly) in doses of 2 mg/kg/day given for 3-days after termination of haloperidol treatment inhibited the enhanced response to apomorphine, as well as the increases in the number of /sup 3/H-spiroperidol binding sites in the striatum. If indeed, the supersensitivity of striatal dopamine receptors is one of the mechanisms in the development of tardive dyskinesia symptoms, the present results suggest that the above peptides may be helpful in ameliorating some of the symptoms of tardive dyskinesia induced by neuroleptic drugs. 31 references, 3 figures.

  15. Systemic injection of kainic acid: Gliosis in olfactory and limbic brain regions quantified with ( sup 3 H)PK 11195 binding autoradiography

    SciTech Connect

    Altar, C.A.; Baudry, M. )

    1990-09-01

    Neurodegenerative diseases may result from excessive stimulation of excitatory amino acid receptors by endogenous ligands. Because neuronal degeneration is associated with glial proliferation and hypertrophy, the degenerative changes throughout rat brain following the systemic administration of kainic acid (12 mg/kg) were mapped with quantitative autoradiography of (3H)PK 11195. This radioligand binds to a mitochondrial benzodiazepine binding site (MBBS) on microglia and astrocytes. Analysis of eight horizontal and four coronal brain levels revealed up to 16-fold increases in (3H)PK 11195 binding from 1 to 5 weeks but not 1 day after kainate injection. Increases in (3H)PK 11195 binding were predominantly in ventral limbic brain regions and olfactory projections to neocortical areas, with the olfactory cortex greater than subiculum/CA1 greater than anterior olfactory nucleus, medial thalamic nucleus, and piriform cortex greater than cingulate cortex and rostral hippocampus greater than dentate gyrus, septum, and amygdala greater than entorhinal cortex and temporal cortex. Little or no enhancement of (3H)PK 11195 binding was observed in numerous regions including the caudate-putamen, substantia nigra, nucleus accumbens, olfactory tubercle, cerebellum, thalamic nuclei, choroid plexus, medulla, parietal or occipital cortex, or pons. A 2-fold greater extent of neurodegeneration was obtained in ventral portions of the olfactory bulb, entorhinal cortex, temporal cortex, and dentate gyrus compared with the dorsal portions of these structures. The pattern of increase in (3H)PK 11195 binding closely matched the patterns of neuronal degeneration reported following parenteral kainate injection. These findings strengthen the notion that quantitative autoradiography of (3H)PK 11195 is a valuable tool to quantify the extent of neuronal degeneration.

  16. Differential effect of N-ethoxycarbonyl-2-ethoxy-1,2-dihydroquinoline (EEDQ) on (/sup 3/H)SCH23390 and (/sup numberH/)forskolin binding in rat striatum

    SciTech Connect

    Norman, A.B.; Wachendorf, T.J.; Sanberg, P.R.

    1989-01-01

    The binding of (/sup 3/H)forskolin to a homogeneous population of binding sites in rat striatum was enhanced by NaF, guanine nucl