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Wikberg JE, Muceniece R, Mandrika I, Prusis P, Lindblom J, Post C, Skottner A. New aspects on the melanocortins and their receptors. Pharmacol Res 2000; 42:393-420. [PMID: 11023702 DOI: 10.1006/phrs.2000.0725] [Citation(s) in RCA: 257] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Knowledge of melanocortins and their receptors has increased tremendously over the last few years. The cloning of five melanocortin receptors, and the discovery of two endogenous antagonists for these receptors, agouti and agouti-related peptide, have sparked intense interest in the field. Here we give a comprehensive review of the pharmacology, physiology and molecular biology of the melanocortins and their receptors. In particular, we review the roles of the melanocortins in the immune system, behaviour, feeding, the cardiovascular system and melanoma. Moreover, evidence is discussed suggesting that while many of the actions of the melanocortins are mediated via melanocortin receptors, some appear to be mediated via mechanisms distinct from melanocortin receptors.
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Review |
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2
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Näsström J, Karlsson U, Post C. Antinociceptive actions of different classes of excitatory amino acid receptor antagonists in mice. Eur J Pharmacol 1992; 212:21-9. [PMID: 1313371 DOI: 10.1016/0014-2999(92)90067-e] [Citation(s) in RCA: 140] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Intrathecal (i.t.) injection of the competitive and selective N-methyl-D-aspartate (NMDA) receptor antagonists DL-2-amino-5-phosphonopentanoic acid (AP5), D-2-amino-7-phosphonoheptanoic acid (AP7), beta-D-aspartylaminomethyl phosphonic acid (Asp-AMP), 3-((+/-)-2-carboxypiperazin-4-yl)-propyl-1-phosphonic acid (CPP) and gamma-D-glutamylaminomethyl phosphonic acid (Glu-AMP) produced dose-dependent and reversible analgesic effects in the mouse hot-plate and formalin tests of nociception. They were slightly more potent in the formalin test but had no or negligible effects in the tail-flick test. The non-selective or non-NMDA receptor antagonists 6-cyano-7-nitro-quinoxalinedione (CNQX), 6,7-dinitro-quinoxalinedione (DNQX), gamma-D-glutamylglycine (gamma DGG), gamma-glutamylaminomethyl sulphonic acid (GAMS), kynurenic acid, cis-2,3-piperidine dicarboxylic acid (cis-PDA; partial agonist) and p-bromobenzoyl piperazine dicarboxylic acid (pBB-PzDA) had the same efficacy in the mouse hot-plate, tail-flick and formalin tests (gamma DGG and pBB-PzDA were not tested in the formalin test). This heterogeneous group of antagonists was somewhat more potent in the tail-flick test and slightly less potent in the formalin test than in the hot-plate test. Of the two glycine site antagonists tested, 7-chlorokynurenic acid (7-Cl-Kyn) and (+/-)-3-amino-1-hydroxy-2-pyrrolidone (HA-966), the effect of the latter was compatible with selective action at the NMDA receptor complex while the action of the former was comparable to those of non-selective excitatory amino acid (EAA) receptor antagonists.(ABSTRACT TRUNCATED AT 250 WORDS)
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33 |
140 |
3
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Kularatne SA, Zhou Z, Yang J, Post CB, Low PS. Design, synthesis, and preclinical evaluation of prostate-specific membrane antigen targeted (99m)Tc-radioimaging agents. Mol Pharm 2009; 6:790-800. [PMID: 19361232 DOI: 10.1021/mp9000712] [Citation(s) in RCA: 137] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
The high mortality and financial burden associated with prostate cancer can be partly attributed to a lack of sensitive screening methods for detection and staging of the disease. Guided by in silico docking studies using the crystal structure of PSMA, we designed and synthesized a series of PSMA-targeted (99m)Tc-chelate complexes for imaging PSMA-expressing human prostate cancer cells (LNCaP cell line). Of the six targeted radioimaging agents synthesized, three were found to bind LNCaP cells with low nanomolar affinity. Moreover, the same three PSMA-targeted imaging agents were shown to localize primarily to LNCaP tumor xenografts in nu/nu mice, with an average of 9.8 +/- 2.4% injected dose/g tissue accumulating in the tumor and only 0.11% injected dose/g tissue retained in the muscle at 4 h postinjection. Collectively, these high affinity, PSMA-specific radioimaging agents demonstrate significant potential for use in localizing prostate cancer masses, monitoring response to therapy, detecting prostate cancer recurrence following surgery, and selecting patients for subsequent PSMA-targeted chemotherapy.
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Research Support, Non-U.S. Gov't |
16 |
137 |
4
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Tagliavini F, McArthur RA, Canciani B, Giaccone G, Porro M, Bugiani M, Lievens PM, Bugiani O, Peri E, Dall'Ara P, Rocchi M, Poli G, Forloni G, Bandiera T, Varasi M, Suarato A, Cassutti P, Cervini MA, Lansen J, Salmona M, Post C. Effectiveness of anthracycline against experimental prion disease in Syrian hamsters. Science 1997; 276:1119-22. [PMID: 9148807 DOI: 10.1126/science.276.5315.1119] [Citation(s) in RCA: 135] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Prion diseases are transmissible neurodegenerative conditions characterized by the accumulation of protease-resistant forms of the prion protein (PrP), termed PrPres, in the brain. Insoluble PrPres tends to aggregate into amyloid fibrils. The anthracycline 4'-iodo-4'-deoxy-doxorubicin (IDX) binds to amyloid fibrils and induces amyloid resorption in patients with systemic amyloidosis. To test IDX in an experimental model of prion disease, Syrian hamsters were inoculated intracerebrally either with scrapie-infected brain homogenate or with infected homogenate coincubated with IDX. In IDX-treated hamsters, clinical signs of disease were delayed and survival time was prolonged. Neuropathological examination showed a parallel delay in the appearance of brain changes and in the accumulation of PrPres and PrP amyloid.
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28 |
135 |
5
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Jones CT, Ma L, Burgner JW, Groesch TD, Post CB, Kuhn RJ. Flavivirus capsid is a dimeric alpha-helical protein. J Virol 2003; 77:7143-9. [PMID: 12768036 PMCID: PMC156156 DOI: 10.1128/jvi.77.12.7143-7149.2003] [Citation(s) in RCA: 131] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The capsid proteins of two flaviviruses, yellow fever virus and dengue virus, were expressed in Escherichia coli and purified to near homogeneity suitable for biochemical characterization and structure determination by nuclear magnetic resonance. The oligomeric properties of the capsid protein in solution were investigated. In the absence of nucleic acid, both proteins were predominantly dimeric in solution. Further analysis of both proteins with far-UV circular dichroism spectroscopy indicated that they were largely alpha-helical. The secondary structure elements of the dengue virus capsid were determined by chemical shift indexing of the sequence-specific backbone resonance assignments. The dengue virus capsid protein devoid of its C-terminal signal sequence was found to be composed of four alpha helices. The longest alpha helix, 20 residues, is located at the C terminus and has an amphipathic character. In contrast, the N terminus was found to be unstructured and could be removed without disrupting the structural integrity of the protein.
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research-article |
22 |
131 |
6
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Schäfer MK, Schwaeble WJ, Post C, Salvati P, Calabresi M, Sim RB, Petry F, Loos M, Weihe E. Complement C1q is dramatically up-regulated in brain microglia in response to transient global cerebral ischemia. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2000; 164:5446-52. [PMID: 10799911 DOI: 10.4049/jimmunol.164.10.5446] [Citation(s) in RCA: 129] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Recent evidence suggests that the pathophysiology of neurodegenerative and inflammatory neurological diseases has a neuroimmunological component involving complement, an innate humoral immune defense system. The present study demonstrates the effects of experimentally induced global ischemia on the biosynthesis of C1q, the recognition subcomponent of the classical complement activation pathway, in the CNS. Using semiquantitative in situ hybridization, immunohistochemistry, and confocal laser scanning microscopy, a dramatic and widespread increase of C1q biosynthesis in rat brain microglia (but not in astrocytes or neurons) within 24 h after the ischemic insult was observed. A marked increase of C1q functional activity in cerebrospinal fluid taken 1, 24, and 72 h after the ischemic insult was determined by C1q-dependent hemolytic assay. In the light of the well-established role of complement and complement activation products in the initiation and maintenance of inflammation, the ischemia-induced increase of cerebral C1q biosynthesis and of C1q functional activity in the cerebrospinal fluid implies that the proinflammatory activities of locally produced complement are likely to contribute to the pathophysiology of cerebral ischemia. Pharmacological modulation of complement activation in the brain may be a therapeutic target in the treatment of stroke.
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129 |
7
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Reddy VS, Giesing HA, Morton RT, Kumar A, Post CB, Brooks CL, Johnson JE. Energetics of quasiequivalence: computational analysis of protein-protein interactions in icosahedral viruses. Biophys J 1998; 74:546-58. [PMID: 9449355 PMCID: PMC1299407 DOI: 10.1016/s0006-3495(98)77813-0] [Citation(s) in RCA: 121] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
Quaternary structure polymorphism found in quasiequivalent virus capsids provides a static framework for studying the dynamics of protein interactions. The same protein subunits are found in different structural environments within these particles, and in some cases, the molecular switching required for the polymorphic quaternary interactions is obvious from high-resolution crystallographic studies. Employing atomic resolution structures, molecular mechanics, and continuum electrostatic methods, we have computed association energies for unique subunit interfaces of three icosahedral viruses, black beetle virus, southern bean virus, and human rhinovirus 14. To quantify the chemical determinants of quasiequivalence, the energetic contributions of individual residues forming quasiequivalent interfaces were calculated and compared. The potential significance of the differences in stabilities at quasiequivalent interfaces was then explored with the combinatorial assembly approach. The analysis shows that the unique association energies computed for each virus serve as a sensitive basis set that may determine distinct intermediates and pathways of virus capsid assembly. The pathways for the quasiequivalent viruses displayed isoenergetic oligomers at specific points, suggesting that these may determine the quaternary structure polymorphism required for the assembly of a quasiequivalent particle.
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research-article |
27 |
121 |
8
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43 |
111 |
9
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Kingston RL, Fitzon-Ostendorp T, Eisenmesser EZ, Schatz GW, Vogt VM, Post CB, Rossmann MG. Structure and self-association of the Rous sarcoma virus capsid protein. Structure 2000; 8:617-28. [PMID: 10873863 DOI: 10.1016/s0969-2126(00)00148-9] [Citation(s) in RCA: 105] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
BACKGROUND The capsid protein (CA) of retroviruses, such as Rous sarcoma virus (RSV), consists of two independently folded domains. CA functions as part of a polyprotein during particle assembly and budding and, in addition, forms a shell encapsidating the genomic RNA in the mature, infectious virus. RESULTS The structures of the N- and C-terminal domains of RSV CA have been determined by X-ray crystallography and solution nuclear magnetic resonance (NMR) spectroscopy, respectively. The N-terminal domain comprises seven alpha helices and a short beta hairpin at the N terminus. The N-terminal domain associates through a small, tightly packed, twofold symmetric interface within the crystal, different from those previously described for other retroviral CAs. The C-terminal domain is a compact bundle of four alpha helices, although the last few residues are disordered. In dilute solution, RSV CA is predominantly monomeric. We show, however, using electron microscopy, that intact RSV CA can assemble in vitro to form both tubular structures constructed from toroidal oligomers and planar monolayers. Both modes of assembly occur under similar solution conditions, and both sheets and tubes exhibit long-range order. CONCLUSIONS The tertiary structure of CA is conserved across the major retroviral genera, yet sequence variations are sufficient to cause change in associative behavior. CA forms the exterior shell of the viral core in all mature retroviruses. However, the core morphology differs between viruses. Consistent with this observation, we find that the capsid proteins of RSV and human immunodeficiency virus type 1 exhibit different associative behavior in dilute solution and assemble in vitro into different structures.
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25 |
105 |
10
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Post CB, Brooks BR, Karplus M, Dobson CM, Artymiuk PJ, Cheetham JC, Phillips DC. Molecular dynamics simulations of native and substrate-bound lysozyme. A study of the average structures and atomic fluctuations. J Mol Biol 1986; 190:455-79. [PMID: 3783708 DOI: 10.1016/0022-2836(86)90015-x] [Citation(s) in RCA: 98] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Molecular dynamics simulations of hen egg-white lysozyme in the free and substrate-bound states are reported and the nature of the average structures and atomic fluctuations are analyzed. Crystallographic water molecules of structural importance, as determined by hydrogen-bonding, were included in the simulations. Comparisons are made between the dynamics and the X-ray results for the atomic positions, the main-chain and side-chain dihedral angles, and the hydrogen-bonding geometry. Improvements over earlier simulations in the potential energy function and methodology resulted in stable trajectories with the C alpha co-ordinates within 1.5 A of the starting X-ray structure. Structural features analyzed in the simulations agreed well with the X-ray results except for some surface residues. The Asx chi 2 dihedral distribution and the geometry of hydrogen bonding at reverse turns show differences; possible causes are discussed. The relation between the magnitudes and time-scales of the residue fluctuations and secondary structural features, such as helices beta-sheets and coiled loops, is examined. Significant differences in the residue mobilities between the simulations of the free and substrate-bound states were found in a region of the enzyme that is in direct contact with the substrate and in a region that is distant from the active-site cleft. The dynamic behavior of the structural water molecules is analyzed by examining the correlation between the fluctuations of the water oxygens and the lysozyme heavy-atoms to which they are hydrogen-bonded.
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39 |
98 |
11
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Zhang Z, Post CB, Smith DL. Amide hydrogen exchange determined by mass spectrometry: application to rabbit muscle aldolase. Biochemistry 1996; 35:779-91. [PMID: 8547258 DOI: 10.1021/bi952227q] [Citation(s) in RCA: 98] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
The protein fragmentation/mass spectrometry method described by Zhang and Smith [(1993) Protein Sci. 2, 522-531] has been extended to measure amide hydrogen exchange rates in rabbit muscle aldolase, a homotetramer with M(r) = 157,000. Following a period of deuterium exchange, the partially deuterated protein was proteolytically fragmented into peptides whose deuterium contents were determined by directly coupled HPLC fast atom bombardment mass spectrometry. Hydrogen exchange rates were determined for amide hydrogens located in short segments derived from 85% of the aldolase backbone. Isotopic exchange rate constants spanning the range from 100 to 0.001 h-1 were determined for the exchange-in times used in this study (2.5 min to 44 h). The exchange rates for amide hydrogens located within short segments differed by as much as 10(4), demonstrating that local structural features dramatically affect the isotopic exchange rates in large proteins. A high level of correlation between the slowing of hydrogen exchange and intramolecular hydrogen bonding in aldolase was found. An exception to this correlation occurs at the subunit interface, where the amide hydrogens in one peptide segment with few amide hydrogen bonds have slower exchange rates than expected, suggesting that the amide hydrogens in this region are effectively shielded from the deuterated solvent. Isotope patterns observed for most peptides were binomial, indicating that hydrogen exchange proceeds through the EX2 mechanism (uncorrelated exchange). However, bimodal isotope patterns were found for peptides derived from three short segments of aldolase (including residues 58-64, 279-283, and 326-337), suggesting structural differences in these regions. A high level of correlation was found between crystallographic B-factors and amide hydrogen exchange rates, suggesting an isotopic exchange mechanism involving localized low-amplitude, high-frequency motions that do not require collective motion of many residues. From a methodology viewpoint, these results demonstrate that the combination of protein fragmentation with mass spectrometry is a useful method for determining the rates at which amide hydrogens located over major portions of large proteins undergo isotopic exchange.
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29 |
98 |
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Post C, Paulsson I. Antinociceptive and neurotoxic actions of substance P analogues in the rat's spinal cord after intrathecal administration. Neurosci Lett 1985; 57:159-64. [PMID: 2412191 DOI: 10.1016/0304-3940(85)90056-4] [Citation(s) in RCA: 84] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Intrathecal administration of both (D-Pro2,D-Trp7,9)-substance P (DPDT) and (D-Arg1,D-Trp7,9,Leu11)-substance P (DADTL) elicited antinociception in hot-plate and tail-flick test, with DADTL as the most potent. The animals injected with 2.0 micrograms DADTL, and several animals administered with DPDT at the same dose, developed bilateral motor blockade of the hind-legs, persisting for up to 3 days after DADTL. The effect of DPDT appeared to be reversible at this dose. On histopathological examination it was found that these animals with persistent paralysis had widespread neuronal necrosis in the lumbar region of the spinal cord. It is concluded that the peptides have antinociceptive effects after the intrathecal administration in rats, but that there is a small margin between the dose producing this effect and that causing irreversible toxic reactions in the spinal cord.
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40 |
84 |
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Post C, Alari L, Hökfelt T. Intrathecal galanin increases the latency in the tail-flick and hot-plate test in mouse. ACTA PHYSIOLOGICA SCANDINAVICA 1988; 132:583-4. [PMID: 2465669 DOI: 10.1111/j.1748-1716.1988.tb08369.x] [Citation(s) in RCA: 84] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
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37 |
84 |
14
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Archer T, Jonsson G, Minor BG, Post C. Noradrenergic-serotonergic interactions and nociception in the rat. Eur J Pharmacol 1986; 120:295-307. [PMID: 3081358 DOI: 10.1016/0014-2999(86)90470-x] [Citation(s) in RCA: 82] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Spinal noradrenaline (NA) depletion in rats, via either systemic N-2-chloroethyl-N-ethyl-2-bromobenzylamine (DSP4) or intrathecal 6-hydroxydopamine (6-OHDA), reversed and/or abolished the analgesic effects of the 5-hydroxytryptamine (5-HT) agonists, 5-methoxy-N,N-dimethyltryptamine (5-MeODMT) and p-chloroamphetamine (PCA), in shock titration, hot-plate and tail-flick measures of pain sensitivity. Spinal NA depletion also abolished the analgesic effects of 5-HT itself, administered intrathecally, in all three nociception tests and potentiated the analgesic effects of intrathecal NA, a demonstration of receptor supersensitivity. Spinal 5-HT depletion, via intrathecal 5,7-dihydroxytryptamine (5,7-DHT), only attenuated 5-MeODMT-induced analgesia in the tail-flick test but potentiated the 5-MeODMT effect in the hot-plate test. Intrathecal 5,7-DHT treatment caused a drastic potentiation of NA-induced analgesia in the shock titration and tail-flick tests but not in the hot-plate test. Biochemical analyses confirmed the NA and 5-HT depletion. The spinal noradrenergic system appears to be an important tonic factor modulating the function of the descending 5-hydroxytryptaminergic pathway.
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39 |
82 |
15
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Moon KD, Post CB, Durden DL, Zhou Q, De P, Harrison ML, Geahlen RL. Molecular basis for a direct interaction between the Syk protein-tyrosine kinase and phosphoinositide 3-kinase. J Biol Chem 2004; 280:1543-51. [PMID: 15536084 DOI: 10.1074/jbc.m407805200] [Citation(s) in RCA: 81] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
After engagement of the B cell receptor for antigen, the Syk protein-tyrosine kinase becomes phosphorylated on multiple tyrosines, some of which serve as docking sites for downstream effectors with SH2 or other phosphotyrosine binding domains. The most frequently identified binding partner for catalytically active Syk identified in a yeast two-hybrid screen was the p85 regulatory subunit of phosphoinositide 3-kinase. The C-terminal SH2 domain of p85 was sufficient for mediating an interaction with tyrosine-phosphorylated Syk. Interestingly, this domain interacted with Syk at phosphotyrosine 317, a site phosphorylated in trans by the Src family kinase, Lyn, and identified previously as a binding site for c-Cbl. This site interacted preferentially with the p85 C-terminal SH2 domain compared with the c-Cbl tyrosine kinase binding domain. Molecular modeling studies showed a good fit between the p85 SH2 domain and a peptide containing phosphotyrosine 317. Tyr-317 was found to be essential for Syk to support phagocytosis mediated by FcgammaRIIA receptors expressed in a heterologous system. These studies establish a new type of p85 binding site that can exist on proteins that serve as substrates for Src family kinases and provide a molecular explanation for observations on direct interactions between Syk and phosphoinositide 3-kinase.
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Research Support, U.S. Gov't, P.H.S. |
21 |
81 |
16
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Gordh T, Jansson I, Hartvig P, Gillberg PG, Post C. Interactions between noradrenergic and cholinergic mechanisms involved in spinal nociceptive processing. Acta Anaesthesiol Scand 1989; 33:39-47. [PMID: 2563622 DOI: 10.1111/j.1399-6576.1989.tb02857.x] [Citation(s) in RCA: 78] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Antinociceptive effects have been demonstrated after systemic and spinal administration of the adrenoceptor agonist clonidine and cholinomimetic drugs in animals and human. The present investigation was undertaken in rats to study the possible interactions between spinal noradrenergic and cholinergic mechanisms in modulating the reaction to nociceptive stimuli. Using the tail immersion test, an additive antinociceptive effect was found between intrathecal (IT) clonidine (10 micrograms) and physostigmine (15 micrograms, IT). The effect of clonidine was attenuated by atropine (15 micrograms, IT). Physostigmine (15 micrograms, IT) antinociception, which was of short duration was abolished by atropine (15 micrograms, IT) and attenuated by phentolamine (20 micrograms, IT). Neostigmine (5 micrograms, IT) produced a prolonged antinociceptive response. In animals pretreated with 6-hydroxydopamine IT, leading to a selective depletion of spinal cord noradrenaline, physostigmine (15 micrograms, IT) was ineffective in altering the nociceptive test response. Neither clonidine, nor physostigmine produced changes in latency times in the hot plate test (58 degrees C) in the doses employed. In conclusion, a clear-cut interaction exists between spinal noradrenergic and cholinergic systems for antinociception. To explain the interactions, several possible mechanisms may be considered, including cholinomimetic effects produced by clonidine, and the presence of muscarinic receptors in the dorsal horn of the spinal cord.
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36 |
78 |
17
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Pevarello P, Bonsignori A, Dostert P, Heidempergher F, Pinciroli V, Colombo M, McArthur RA, Salvati P, Post C, Fariello RG, Varasi M. Synthesis and anticonvulsant activity of a new class of 2-[(arylalky)amino]alkanamide derivatives. J Med Chem 1998; 41:579-90. [PMID: 9484507 DOI: 10.1021/jm970599m] [Citation(s) in RCA: 76] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Although most epilepsies are adequately treated by conventional antiepileptic therapy, there remains an unfulfilled need for safer and more effective anticonvulsant agents. Starting from milacemide, a weak anticonvulsant, and trying to elucidate its mechanism of action, we discovered a structurally novel class of potent and preclinically safe anticonvulsants. Here we report the structure-activity relationship (SAR) study within this series of compounds. Different parts of the structural lead 2-[[4-(3-chlorobenzoxy)benzyl]amino]acetamide (6) were thus varied (Figure 1), and many potent anticonvulsants were found. As an outcome of this study, 57 ((S)-2-[[4-(3-fluorobenzoxy)benzyl]amino]propanamide methanesulfonate, PNU-151774E) emerged as a promising candidate for further development for its potent anticonvulsant activity and outstanding therapeutic indexes (TIs) in different animal tests.
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27 |
76 |
18
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Alehagen U, Johansson P, Björnstedt M, Rosén A, Post C, Aaseth J. Relatively high mortality risk in elderly Swedish subjects with low selenium status. Eur J Clin Nutr 2015; 70:91-6. [PMID: 26105108 PMCID: PMC4709701 DOI: 10.1038/ejcn.2015.92] [Citation(s) in RCA: 75] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2014] [Revised: 04/15/2015] [Accepted: 04/19/2015] [Indexed: 12/31/2022]
Abstract
Background/Objectives: The daily dietary intake of selenium (Se), an essential trace element, is still low in Sweden in spite of decades of nutritional information campaigns and the effect of this on the public health is presently not well known. The objective of this study was to determine the serum Se levels in an elderly Swedish population and to analyze whether a low Se status had any influence on mortality. Subjects/Methods: Six-hundred sixty-eight (n=668) elderly participants were invited from a municipality and evaluated in an observational study. Individuals were followed for 6.8 years and Se levels were re-evaluated in 98 individuals after 48 months. Clinical examination of all individuals included functional classification, echocardiography, electrocardiogram and serum Se measurement. All mortality was registered and endpoints of mortality were assessed by Kaplan–Meier plots, and Cox proportional hazard ratios adjusted for potential confounding factors were calculated. Results: The mean serum Se level of the study population (n=668) was 67.1 μg/l, corresponding to relatively low Se intake. After adjustment for male gender, smoking, ischemic heart disease, diabetes, chronic obstructive pulmonary disease and impaired heart function, persons with serum Se in the lowest quartile had 43% (95% confidence interval (CI): 1.02–2.00) and 56% (95% CI: 1.03–2.36) increased risk for all-cause and cardiovascular mortality, respectively. The result was not driven by inflammatory effects on Se concentration in serum. Conclusion: The mean serum Se concentration in an elderly Swedish population was 67.1 μg/l, which is below the physiological saturation level for several selenoprotein enzymes. This result may suggest the value of modest Se supplementation in order to improve the health of the Swedish population.
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Journal Article |
10 |
75 |
19
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Post C. Antinociceptive effects in mice after intrathecal injection of 5'-N-ethylcarboxamide adenosine. Neurosci Lett 1984; 51:325-30. [PMID: 6097841 DOI: 10.1016/0304-3940(84)90397-5] [Citation(s) in RCA: 70] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
When injected intrathecally in mice in a volume of 5 microliter, adenosine had no effect on tail-flick or hot-plate reaction latencies at dosages up to 1 mM concentration. There were no other behavioral effects observed either. Injecting 1 mM of the adenosine receptor agonist, 5'-N-ethylcarboxamide adenosine (NECA) caused both motor paralysis of the hind-legs with a duration of approximately 4 h and simultaneous antinociception. A slight weakness of the hindlegs, but a profound antinociceptive effect, was observed after the 100 microM dose only. After 10 microM, there was no effect on motor behavior but still a prolongation of the tail-flick and hot-plate reaction latencies. Pretreatment with the adenosine receptor antagonist theophylline attenuated the antinociceptive effect of NECA. Activation of spinal adenosine receptors thus appears to selectively elicit analgesia.
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41 |
70 |
20
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Karlsson JA, Finney MJ, Persson CG, Post C. Substance P antagonists and the role of tachykinins in non-cholinergic bronchoconstriction. Life Sci 1984; 35:2681-91. [PMID: 6083429 DOI: 10.1016/0024-3205(84)90038-9] [Citation(s) in RCA: 69] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
Electrical field stimulation of guinea-pig isolated hilus bronchi induced tetrodotoxin-sensitive contractions of which only a minor part could be inhibited by atropine. The remaining non-cholinergic bronchoconstriction was antagonized by a heptapeptide and an undecapeptide substance P (SP) analogue (Arg5, D-Trp7,9) SP5-11, IC50 = 24.0 microM and (D-Pro2, D-Trp 7,9) SP, IC50 = 10.0 microM. Of the exogenously added tachykinins, both eledoisin (8 times) and physalaemin (3 times) were more potent bronchoconstrictors than SP. Pretreatment with the SP-analogues shifted concentration-response curves to the tachykinins to the right, eledoisin being most readily antagonized. (Arg5, D-Trp 7,9) SP 5-11 also antagonized the neural response more readily than that of SP. In addition, in the frog isolated sciatic nerve preparation the two SP-analogues were found to possess potent lidocaine-like neurodepressant actions which further complicated the interpretation of the neural inhibitory effects of these compounds. It is concluded that if a tachykinin contributes to non-cholinergic bronchoconstriction, an eledoisin-like peptide is a more likely candidate than SP itself. Since SP-antagonists may have local anaesthetic properties their value as tools in neurophysiology seems limited. Inferentially, the non-cholinergic bronchoconstrictive neurotransmitter remains to be identified.
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Karlsten R, Gordh T, Hartvig P, Post C. Effects of intrathecal injection of the adenosine receptor agonists R-phenylisopropyl-adenosine and N-ethylcarboxamide-adenosine on nociception and motor function in the rat. Anesth Analg 1990; 71:60-4. [PMID: 2363530 DOI: 10.1213/00000539-199007000-00010] [Citation(s) in RCA: 68] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
R-phenylisopropyl-adenosine, which has an affinity for the adenosine A1 receptor higher than that for the A2 receptor, and N-ethylcarboxamide-adenosine, which has near equal affinity for the A1 and A2 receptors, were injected intrathecally into rats to evaluate differences in antinociceptive effect and motor impairment. Using the tail-immersion test, both compounds had antinociceptive effects. Motor function was evaluated during spontaneous movement in a free space. N-ethylcarboxamide-adenosine rapidly impaired motor function even after low intrathecal doses. R-phenylisopropyl-adenosine also induced motor impairment, but only after high intrathecal doses, and onset was much slower. These results suggest that the receptor selectivity of R-phenylisopropyl-adenosine is diminished at higher doses and that the motor impairment is an A2-receptor-mediated effect. A selective A1 receptor agonist, e.g., R-phenylisopropyl-adenosine, which produces a good antinociceptive effect without motor impairment, is more promising as a drug of possible use for the future treatment of clinical pain.
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Post CB, Ray WJ. Reexamination of induced fit as a determinant of substrate specificity in enzymatic reactions. Biochemistry 1995; 34:15881-5. [PMID: 8519743 DOI: 10.1021/bi00049a001] [Citation(s) in RCA: 67] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
It has been argued that a substrate-induced conformational change involving the orientation of catalytic groups cannot affect the specificity for two substrates in an enzymatic system where the chemical step is rate limiting, because such an induced fit would alter the catalytic efficiency for both to an equal extent. To the contrary, the generalized induced-fit treatment described here shows that when critical substrate-specific conformational changes in the enzyme persist in the transition state, specificity is linked to conformational differences between the reactive complex for a good substrate and the related complex for a poor one. Conformational differences are a determinant of specificity when the reaction proceeds via an "induced-fit" transition state. Our treatment also shows that such conformational changes can enhance the specificity of an enzyme with suboptimal catalytic efficiency. If substrate-dependent conformational differences in a primative enzyme can enhance specificity, evolutionary pressure to increase specificity could inseparably link enzymatic specificity to induced conformational changes.
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Post CB, Zimm BH. Light-scattering study of DNA condensation: competition between collapse and aggregation. Biopolymers 1982; 21:2139-60. [PMID: 7171730 DOI: 10.1002/bip.360211105] [Citation(s) in RCA: 67] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
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Karlsten R, Gordh T, Post C. Local antinociceptive and hyperalgesic effects in the formalin test after peripheral administration of adenosine analogues in mice. PHARMACOLOGY & TOXICOLOGY 1992; 70:434-8. [PMID: 1438021 DOI: 10.1111/j.1600-0773.1992.tb00503.x] [Citation(s) in RCA: 62] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Adenosine administered to humans has been reported to induce pain after intravenous administration. On the other hand adenosine analogues have been shown to possess antinociceptive effects after peripheral and intrathecal administration in animals. The aim of the present study was to investigate the effect of peripheral administration of adenosine agonists with different affinities for the A1 and A2 adenosine receptors on a persistent pain stimulus using the formalin test. The drugs chosen were, R-phenylisopropyl-adenosine (R-PIA) with high affinity for the A1 receptor, N-ethylcarboxamide-adenosine (NECA) with almost equal affinity for the A1 and A2 receptor and 2-(2-aminoethylamino)-carbonylethylphenylethylamino-adenosin e (APEC) with high affinity for the A2 receptor. The drugs were mixed with formalin and administered subcutaneously into the dorsal hind paw in mice to study the local effects. They were also injected separately from the formalin solution in different paws to evaluate the systemic effect. The total time of licking the injected paw during the first 5 min. was recorded. In high doses all compounds reduced the licking activity, but a low dose of APEC (1 microM) injected together with the formalin solution had an algesic effect. All effects were antagonized by theophylline. These results suggests that A1 adenosine receptors mediate a local peripheral antinociceptive effect and the involvement of local peripheral A2 receptors in the enhancement of the algesic response.
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Abstract
Picornaviruses are inactivated by a family of hydrophobic drugs that bind at an internal site in the viral capsid and inhibit viral uncoating. A basis for the capsid stabilization previously unrecognized is revealed by molecular dynamics simulations of the antiviral drug WIN52084s bound to a hydrophobic pocket of solvated human rhinovirus 14. Isothermal compressibilities of the complex and human rhinovirus 14 without the antiviral drug calculated from density fluctuations show that the presence of WIN52084s increases the compressibility of the viral capsid near the antiviral drug. This counterintuitive result is understandable on the basis of the empirical evidence of thermal melting temperatures and protein-folding entropies of globular proteins. Based on this evidence, we propose that a larger compressibility from drug binding confers greater thermal stability to capsid proteins by increasing the conformational entropy of capsids, thereby diminishing the entropy gain with uncoating. We suggest that compressibility is fundamental to the structural integrity of viral capsids and that examination of compressibility and antiviral activity will provide insights into the disassembly process.
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