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Lee YS, O'Connor RD, Vasalatiy O. Investigation of Two Zr-p-NO 2Bn-DOTA Isomers via NMR and Quantum Chemical Studies. Eur J Inorg Chem 2023; 26:e202300439. [PMID: 38560747 PMCID: PMC10977960 DOI: 10.1002/ejic.202300439] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2023] [Indexed: 04/04/2024]
Abstract
A combination of NMR studies and quantum chemical calculations were employed to investigate the structure and energetics of Zr4+ chelates of pNO2Bn-DOTA. We have demonstrated that two discrete regioisomeric chelates are generated during the complex formation. The nitrobenzyl substituent can adopt either an equatorial corner or side position on the macrocyclic ring. These regioisomers are incapable of interconversion and were isolated by HPLC. The corner isomer is more stable than the side, and the SAP conformer of both regioisomers is energetically more favorable than the corresponding TSAP conformer.
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Affiliation(s)
- Yong Sok Lee
- Bioinformatics and Computational Biosciences Branch, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| | - Robert D O'Connor
- Laboratory of Bioorganic Chemistry, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| | - Olga Vasalatiy
- Chemistry and Synthesis Center, National Heart, Lung, and Blood Institute, National Institutes of Health, Rockville, MD 20850, USA
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2
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Fallot LB, Suresh RR, Fisher CL, Salmaso V, O'Connor RD, Kaufman N, Gao ZG, Auchampach JA, Jacobson KA. Structure-Activity Studies of 1 H-Imidazo[4,5- c]quinolin-4-amine Derivatives as A 3 Adenosine Receptor Positive Allosteric Modulators. J Med Chem 2022; 65:15238-15262. [PMID: 36367749 PMCID: PMC10354740 DOI: 10.1021/acs.jmedchem.2c01170] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
We previously reported 1H-imidazo[4,5-c]quinolin-4-amines as A3 adenosine receptor (A3AR) positive allosteric modulators (PAMs). A3AR agonists, but not PAMs, are in clinical trials for inflammatory diseases and liver conditions. We synthesized new analogues to distinguish 2-cyclopropyl antagonist 17 (orthosteric interaction demonstrated by binding and predicted computationally) from PAMs (derivatives with large 2-alkyl/cycloalkyl/bicycloalkyl groups). We predicted PAM binding at a hydrophobic site on the A3AR cytosolic interface. Although having low Caco-2 permeability and high plasma protein binding, hydrophobic 2-cyclohept-4-enyl-N-3,4-dichlorophenyl, MRS7788 18, and 2-heptan-4-yl-N-4-iodophenyl, MRS8054 39, derivatives were orally bioavailable in rat. 2-Heptan-4-yl-N-3,4-dichlorophenyl 14 and 2-cyclononyl-N-3,4-dichlorophenyl 20 derivatives and 39 greatly enhanced Cl-IB-MECA-stimulated [35S]GTPγS binding Emax, with only 12b trending toward decreasing the agonist EC50. A feasible route for radio-iodination at the p-position of a 4-phenylamino substituent suggests a potential radioligand for allosteric site binding. Herein, we advanced an allosteric approach to developing A3AR-activating drugs that are potentially event- and site-specific in action.
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Affiliation(s)
- Lucas B Fallot
- Molecular Recognition Section, Laboratory of Bioorganic Chemistry, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, 9000 Rockville Pike, Bethesda, Maryland 20892, United States
- Department of Biochemistry and Molecular Biology, Uniformed Services University of the Health Sciences, 4301 Jones Bridge Road, Bethesda, Maryland 20814, United States
- Department of Chemistry and Life Science, United States Military Academy, 646 Swift Road, West Point, New York 10996, United States
| | - R Rama Suresh
- Molecular Recognition Section, Laboratory of Bioorganic Chemistry, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, 9000 Rockville Pike, Bethesda, Maryland 20892, United States
| | | | - Veronica Salmaso
- Molecular Recognition Section, Laboratory of Bioorganic Chemistry, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, 9000 Rockville Pike, Bethesda, Maryland 20892, United States
| | - Robert D O'Connor
- Molecular Recognition Section, Laboratory of Bioorganic Chemistry, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, 9000 Rockville Pike, Bethesda, Maryland 20892, United States
| | - Noy Kaufman
- Molecular Recognition Section, Laboratory of Bioorganic Chemistry, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, 9000 Rockville Pike, Bethesda, Maryland 20892, United States
| | - Zhan-Guo Gao
- Molecular Recognition Section, Laboratory of Bioorganic Chemistry, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, 9000 Rockville Pike, Bethesda, Maryland 20892, United States
| | | | - Kenneth A Jacobson
- Molecular Recognition Section, Laboratory of Bioorganic Chemistry, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, 9000 Rockville Pike, Bethesda, Maryland 20892, United States
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Remcho TP, Guggilapu SD, Cruz P, Nardone GA, Heffernan G, O'Connor RD, Bewley CA, Wellems TE, Lane KD. Regioisomerization of Antimalarial Drug WR99210 Explains the Inactivity of a Commercial Stock. Antimicrob Agents Chemother 2020; 65:e01385-20. [PMID: 33077647 PMCID: PMC7927815 DOI: 10.1128/aac.01385-20] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2020] [Accepted: 10/09/2020] [Indexed: 11/20/2022] Open
Abstract
WR99210, a former antimalarial drug candidate now widely used for the selection of Plasmodium transfectants, selectively targets the parasite's dihydrofolate reductase thymidine synthase bifunctional enzyme (DHFR-TS) but not human DHFR, which is not fused with TS. Accordingly, WR99210 and plasmids expressing the human dhfr gene have become valued tools for the genetic modification of parasites in the laboratory. Concerns over the ineffectiveness of WR99210 from some sources encouraged us to investigate the biological and chemical differences of supplies from two different companies (compounds 1 and 2). Compound 1 proved effective at low nanomolar concentrations against Plasmodium falciparum parasites, whereas compound 2 was ineffective, even at micromolar concentrations. Intact and fragmented mass spectra indicated identical molecular formulae of the unprotonated (free base) structures of compounds 1 and 2; however, the compounds displayed differences by thin-layer chromatography, reverse-phase high-performance liquid chromatography, and UV-visible spectroscopy, indicating important isomeric differences. Structural evaluations by 1H, 13C, and 15N nuclear magnetic resonance spectroscopy confirmed compound 1 as WR99210 and compound 2 as a dihydrotriazine regioisomer. Induced fit computational docking models showed that compound 1 binds tightly and specifically in the P. falciparum DHFR active site, whereas compound 2 fits poorly to the active site in loose and varied orientations. Stocks and concentrates of WR99210 should be monitored for the presence of regioisomer 2, particularly when they are not supplied as the hydrochloride salt or are exposed to basic conditions that may promote rearrangement. Absorption spectroscopy can serve for assays of the unrearranged and rearranged triazines.
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Affiliation(s)
- T Parks Remcho
- Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, Maryland, USA
| | - Sravanthi D Guggilapu
- Laboratory of Bioorganic Chemistry, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland, USA
| | - Phillip Cruz
- Office of Cyber Infrastructure and Computational Biology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, USA
| | - Glenn A Nardone
- Research Technologies Branch, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, Maryland, USA
| | - Gavin Heffernan
- Jacobus Pharmaceutical Company, Inc., Princeton, New Jersey, USA
| | - Robert D O'Connor
- Laboratory of Bioorganic Chemistry, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland, USA
| | - Carole A Bewley
- Laboratory of Bioorganic Chemistry, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland, USA
| | - Thomas E Wellems
- Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, Maryland, USA
| | - Kristin D Lane
- Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, Maryland, USA
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Xu P, Korcová J, Baráth P, Čížová A, Valáriková J, Qadri F, Kelly M, O'Connor RD, Ryan ET, Bystrický S, Kováč P. Corrigendum: Isolation, Purification, Characterization and Direct Conjugation of the Lipid A‐Free Lipopolysaccharide of
Vibrio cholerae
O139. Chemistry 2020; 26:8828. [DOI: 10.1002/chem.202001720] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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Liu HB, Imler GH, Baldridge KK, O'Connor RD, Siegel JS, Deschamps JR, Bewley CA. X-ray Crystallography and Unexpected Chiroptical Properties Reassign the Configuration of Haliclonadiamine. J Am Chem Soc 2020; 142:2755-2759. [PMID: 31986017 DOI: 10.1021/jacs.9b12926] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Haliclonadiamine and papuamine are bis-indane marine natural products isolated from the marine sponge Haliclona sp. Their relative structures were previously reported to differ by inversion at only one of their eight shared stereocenters. Here X-ray crystallography shows the opposite to be true: papuamine has a 1R,3S,8R,9S,14S,15R,20S,22R configuration, while haliclonadiamine has a 1S,3R,8S,9R,14R,15S,20R,22R configuration. Paradoxically the ECD of each structure displays a negative Cotton effect. X-ray crystallography reveals the two structures adopt similar conformations of their 13-membered macrocyclic core that comprises a configurationally relevant diene. B97x-D/Def2-TZVPP-(MeOH)-calculated ECD supports the diene configuration with the macrocycle dominating the ECD Cotton effect for haliclonadiamine and papuamine. Additional crystallographic and chiroptical analyses of three sponge samples from geographically distant locations indicate this pair of natural products always exists as a configurationally related couple. The co-discovery of a biosynthetic precursor, halichondriamine C, present in these same Haliclona samples must be considered when discussing any biosynthetic pathway. Taken together, this work justifies a reassignment of haliclonadiamine's structure and opens the question of how this complex stereochemical relationship between haliclonadiamine and palauamine arises biosynthetically.
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Affiliation(s)
- Hong-Bing Liu
- Laboratory of Bioorganic Chemistry, National Institute of Diabetes and Digestive and Kidney Diseases , National Institutes of Health , Bethesda , Maryland 20892-0820 , United States
| | - Gregory H Imler
- Center for Biomolecular Science and Engineering , Naval Research Laboratory , Code 6930, Washington , D.C. 20375 , United States
| | - Kim K Baldridge
- Health Science Platform , Tianjin University , 92 Weijin Road, Nankai District , Tianjin 300072 , P.R. China
| | - Robert D O'Connor
- Laboratory of Bioorganic Chemistry, National Institute of Diabetes and Digestive and Kidney Diseases , National Institutes of Health , Bethesda , Maryland 20892-0820 , United States
| | - Jay S Siegel
- Health Science Platform , Tianjin University , 92 Weijin Road, Nankai District , Tianjin 300072 , P.R. China
| | - Jeffrey R Deschamps
- Center for Biomolecular Science and Engineering , Naval Research Laboratory , Code 6930, Washington , D.C. 20375 , United States
| | - Carole A Bewley
- Laboratory of Bioorganic Chemistry, National Institute of Diabetes and Digestive and Kidney Diseases , National Institutes of Health , Bethesda , Maryland 20892-0820 , United States
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Xu P, Korcová J, Baráth P, Čížová A, Valáriková J, Qadri F, Kelly M, O'Connor RD, Ryan ET, Bystrický S, Kováč P. Cover Feature: Isolation, Purification, Characterization and Direct Conjugation of the Lipid A‐Free Lipopolysaccharide of
Vibrio cholerae
O139 (Chem. Eur. J. 56/2019). Chemistry 2019. [DOI: 10.1002/chem.201903396] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Peng Xu
- Laboratory of Bioorganic Chemistry, National Institute of Diabetes and Digestive and Kidney DiseasesNational Institutes of Health 9000 Rockville Bethesda MD 20892-0815 USA
| | - Jana Korcová
- Institute of ChemistrySlovak Academy of Sciences 84238 Bratislava Slovak Republic
- Institute of Epidemiology, Faculty of MedicineComenius University Špitálska 24 81372 Bratislava Slovak Republic
| | - Peter Baráth
- Institute of ChemistrySlovak Academy of Sciences 84238 Bratislava Slovak Republic
| | - Alžbeta Čížová
- Institute of ChemistrySlovak Academy of Sciences 84238 Bratislava Slovak Republic
| | - Jana Valáriková
- Institute of ChemistrySlovak Academy of Sciences 84238 Bratislava Slovak Republic
| | - Firdausi Qadri
- Infectious Diseases DivisionInternational Centre for, Diarrhoeal Disease Research, Bangladesh (icddr,b) Dhaka Bangladesh
| | - Meagan Kelly
- Division of Infectious DiseasesMassachusetts General Hospital Boston MA 02114 USA
| | - Robert D. O'Connor
- Laboratory of Bioorganic Chemistry, National Institute of Diabetes and Digestive and Kidney DiseasesNational Institutes of Health 9000 Rockville Bethesda MD 20892-0815 USA
| | - Edward T. Ryan
- Division of Infectious DiseasesMassachusetts General Hospital Boston MA 02114 USA
- Harvard Medical School Boston MA 02115 USA
- Department of Immunology and Infectious DiseasesHarvard T.H. Chan School of Public Health Boston MA 02115 USA
| | - Slavomír Bystrický
- Institute of ChemistrySlovak Academy of Sciences 84238 Bratislava Slovak Republic
| | - Pavol Kováč
- Laboratory of Bioorganic Chemistry, National Institute of Diabetes and Digestive and Kidney DiseasesNational Institutes of Health 9000 Rockville Bethesda MD 20892-0815 USA
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Xu P, Korcová J, Baráth P, Čížová A, Valáriková J, Qadri F, Kelly M, O'Connor RD, Ryan ET, Bystrický S, Kováč P. Isolation, Purification, Characterization and Direct Conjugation of the Lipid A-Free Lipopolysaccharide of Vibrio cholerae O139. Chemistry 2019; 25:12946-12956. [PMID: 31306528 DOI: 10.1002/chem.201902263] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2019] [Revised: 07/09/2019] [Indexed: 11/05/2022]
Abstract
The lipopolysaccharide (LPS) of Vibrio cholerae O139, strain CIRS245, was isolated conventionally, and the lipid A was removed by mild acid hydrolysis (0.1 m NaOAc buffer containing 1 % SDS, pH 4.2, 95 °C, 8 h). The crude product was a complex mixture consisting mainly of constituent fragments of the O-specific polysaccharide-core (OSPc). The OSPc was only a minor component in the mixture. Two-stage purification of the crude OSPc by HPLC gave pure OSPc fragment of the LPS, as shown by NMR spectroscopy, analytical HPLC and ESI-MS. This material is the purest OSPc fragment of the LPS from Vibrio cholerae O139 reported to date. The purified OSPc was readily converted to the corresponding methyl squarate derivative and the latter was conjugated to BSA. The conjugate, when examined by ELISA, showed immunoreactivity with sera from patients in Bangladesh recovering from cholera caused by V. cholerae O139, but not O1.
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Affiliation(s)
- Peng Xu
- Laboratory of Bioorganic Chemistry, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, 9000 Rockville, Bethesda, MD, 20892-0815, USA
| | - Jana Korcová
- Institute of Chemistry, Slovak Academy of Sciences, 84238, Bratislava, Slovak Republic.,Institute of Epidemiology, Faculty of Medicine, Comenius University, Špitálska 24, 81372, Bratislava, Slovak Republic
| | - Peter Baráth
- Institute of Chemistry, Slovak Academy of Sciences, 84238, Bratislava, Slovak Republic
| | - Alžbeta Čížová
- Institute of Chemistry, Slovak Academy of Sciences, 84238, Bratislava, Slovak Republic
| | - Jana Valáriková
- Institute of Chemistry, Slovak Academy of Sciences, 84238, Bratislava, Slovak Republic
| | - Firdausi Qadri
- Infectious Diseases Division, International Centre for, Diarrhoeal Disease Research, Bangladesh (icddr,b), Dhaka, Bangladesh
| | - Meagan Kelly
- Division of Infectious Diseases, Massachusetts General Hospital, Boston, MA, 02114, USA
| | - Robert D O'Connor
- Laboratory of Bioorganic Chemistry, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, 9000 Rockville, Bethesda, MD, 20892-0815, USA
| | - Edward T Ryan
- Division of Infectious Diseases, Massachusetts General Hospital, Boston, MA, 02114, USA.,Harvard Medical School, Boston, MA, 02115, USA.,Department of Immunology and Infectious Diseases, Harvard T.H. Chan School of Public Health, Boston, MA, 02115, USA
| | - Slavomír Bystrický
- Institute of Chemistry, Slovak Academy of Sciences, 84238, Bratislava, Slovak Republic
| | - Pavol Kováč
- Laboratory of Bioorganic Chemistry, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, 9000 Rockville, Bethesda, MD, 20892-0815, USA
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Scott FJ, Alaniva N, Golota NC, Sesti EL, Saliba EP, Price LE, Albert BJ, Chen P, O'Connor RD, Barnes AB. A versatile custom cryostat for dynamic nuclear polarization supports multiple cryogenic magic angle spinning transmission line probes. J Magn Reson 2018; 297:23-32. [PMID: 30342370 DOI: 10.1016/j.jmr.2018.10.002] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/06/2018] [Revised: 09/29/2018] [Accepted: 10/02/2018] [Indexed: 06/08/2023]
Abstract
Dynamic nuclear polarization (DNP) with cryogenic magic angle spinning (MAS) provides significant improvements in NMR sensitivity, yet presents unique technical challenges. Here we describe a custom cryostat and suite of NMR probes capable of manipulating nuclear spins with multi-resonant radiofrequency circuits, cryogenic spinning below 6 K, sample exchange, and microwave coupling for DNP. The corrugated waveguide and six transfer lines needed for DNP and cryogenic spinning functionality are coupled to the probe from the top of the magnet. Transfer lines are vacuum-jacketed and provide bearing and drive gas, variable temperature fluid, two exhaust pathways, and a sample ejection port. The cryostat thermally isolates the magnet bore, thereby protecting the magnet and increasing cryogen efficiency. This novel design supports cryogenic MAS-DNP performance over an array of probes without altering DNP functionality. We present three MAS probes (two supporting 3.2 mm rotors and one supporting 9.5 mm rotors) interfacing with the single cryostat. Mechanical details, transmission line radio frequency design, and performance of the cryostat and three probes are described.
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Affiliation(s)
- Faith J Scott
- Department of Chemistry, Washington University in St. Louis, St. Louis, MO 63130, USA
| | - Nicholas Alaniva
- Department of Chemistry, Washington University in St. Louis, St. Louis, MO 63130, USA
| | - Natalie C Golota
- Department of Chemistry, Washington University in St. Louis, St. Louis, MO 63130, USA
| | - Erika L Sesti
- Department of Chemistry, Washington University in St. Louis, St. Louis, MO 63130, USA
| | - Edward P Saliba
- Department of Chemistry, Washington University in St. Louis, St. Louis, MO 63130, USA
| | - Lauren E Price
- Department of Chemistry, Washington University in St. Louis, St. Louis, MO 63130, USA
| | - Brice J Albert
- Department of Chemistry, Washington University in St. Louis, St. Louis, MO 63130, USA
| | - Pinhui Chen
- Department of Chemistry, Washington University in St. Louis, St. Louis, MO 63130, USA; Department of Physics, Washington University in St. Louis, St. Louis, MO 63130, USA
| | - Robert D O'Connor
- Laboratory of Bioorganic Chemistry, National Institute of Diabetes and Digestive and Kidney Diseases, Bethesda, MD 20892, USA
| | - Alexander B Barnes
- Department of Chemistry, Washington University in St. Louis, St. Louis, MO 63130, USA.
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Ciancetta A, O'Connor RD, Paoletta S, Jacobson KA. Demystifying P2Y 1 Receptor Ligand Recognition through Docking and Molecular Dynamics Analyses. J Chem Inf Model 2017; 57:3104-3123. [PMID: 29182323 DOI: 10.1021/acs.jcim.7b00528] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
We performed a molecular modeling analysis of 100 nucleotide-like bisphosphates and 46 non-nucleotide arylurea derivatives previously reported as P2Y1R binders using the recently solved hP2Y1R structures. We initially docked the compounds at the X-ray structures and identified the binding modes of representative compounds highlighting key patterns in the structure-activity relationship (SAR). We subsequently subjected receptor complexes with selected key agonists (2MeSADP and MRS2268) and antagonists (MRS2500 and BPTU) to membrane molecular dynamics (MD) simulations (at least 200 ns run in triplicate, simulation time 0.6-1.6 μs per ligand system) while considering alternative protonation states of nucleotides. Comparing the temporal evolution of the ligand-protein interaction patterns with available site-directed mutagenesis (SDM) data and P2Y1R apo state simulation provided further SAR insights and suggested reasonable explanations for loss/gain of binding affinity as well as the most relevant charged species for nucleotide ligands. The MD analysis also predicted local conformational changes required for the receptor inactive state to accommodate nucleotide agonists.
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Affiliation(s)
- Antonella Ciancetta
- Molecular Recognition Section, Laboratory of Bioorganic Chemistry, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health , Bethesda, Maryland 20892, United States
| | - Robert D O'Connor
- Molecular Recognition Section, Laboratory of Bioorganic Chemistry, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health , Bethesda, Maryland 20892, United States
| | - Silvia Paoletta
- Molecular Recognition Section, Laboratory of Bioorganic Chemistry, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health , Bethesda, Maryland 20892, United States
| | - Kenneth A Jacobson
- Molecular Recognition Section, Laboratory of Bioorganic Chemistry, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health , Bethesda, Maryland 20892, United States
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Abstract
We have used C{F}, N{F}, and N{P} rotational-echo double resonance NMR to determine the location and conformation of 19F and 15N double-labeled plusbacin A3 and of double-labeled deslipo-plusbacin A3, each bound to the cell walls of whole cells of Staphyloccocus aureus grown in media containing [1-13C]glycine. The 31P is primarily in wall teichoic acid. Approximately 25% of plusbacin headgroups (the cyclic depsipeptide backbone) are in a closed conformation (N-F separation of 6 Å), while 75% are in a more open conformation (N-F separation of 12 Å). The closed headgroups have no contact with wall teichoic acid, whereas the open headgroups have a strong contact. This places the closed headgroups in hydrophobic regions of the cell wall and the open headgroups in hydrophilic regions. None of the plusbacin tails have contact with the 31P of either wall teichoic acid or the cell membrane and thus are in hydrophobic regions of the cell wall. In addition, both heads and tails of plusbacin A3 have contact with the glycyl 13C incorporated in cell-wall peptidoglycan pentaglycyl bridges and with 13C-labeled purines near the membrane surface. We interpret these results in terms of a dual mode of action for plusbacin A3: first, disruption of the peptidoglycan layer nearest to the membrane surface by closed-conformation plusbacin A3 leading to an inhibition of chain extension by transglycosylation; second, thinning and disruption of the membrane (possibly including disruption of ATP-binding cassette transporters embedded in the membrane) by open-conformation plusbacin A3, thereby leading to release of ATP to the hydrophilic regions of the cell wall and subsequent binding by plusbacin A3.
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Affiliation(s)
- Robert D. O'Connor
- Department of Chemistry, Washington University, St. Louis, Missouri 63130, United States
| | - Manmilan Singh
- Department of Chemistry, Washington University, St. Louis, Missouri 63130, United States
| | - James Chang
- Department of Chemistry and Biochemistry, Baylor University, Waco, Texas 76798, United States
| | - Sung Joon Kim
- Department of Chemistry and Biochemistry, Baylor University, Waco, Texas 76798, United States
| | - Michael VanNieuwenhze
- Department of Chemistry, Indiana University, Bloomington, Indiana 47405, United States
| | - Jacob Schaefer
- Department of Chemistry, Washington University, St. Louis, Missouri 63130, United States
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Muhammad A, van der Lely AJ, O'Connor RD, Delhanty PJ, Dal J, Dallenga AH, Feelders RA, Janssen JAMJL, Jorgensen JOL, Neggers SJCMM. What is the efficacy of switching to weekly pegvisomant in acromegaly patients well controlled on combination therapy? Eur J Endocrinol 2016; 174:663-7. [PMID: 26903550 DOI: 10.1530/eje-15-1150] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/24/2015] [Accepted: 02/19/2016] [Indexed: 11/08/2022]
Abstract
CONTEXT Although combination therapy of acromegaly with long-acting somatostatin analogs (LA-SSAs) and pegvisomant (PEGV) normalizes insulin-like growth factor-1 (IGF1) levels in the majority of patients, it requires long-term adherence. Switching from combination therapy to monotherapy with weekly PEGV could improve patients' comfort, but the efficacy is unknown. OBJECTIVE To assess the efficacy of switching to PEGV monotherapy in patients well controlled on combination therapy of LA-SSAs and PEGV. DESIGN Single-center, open-label observational pilot study. LA-SSA therapy was discontinued at baseline and all patients were switched to PEGV monotherapy for 12 months. If IGF1 levels exceeded 1.0 times upper limit of normal (ULN), PEGV dose was increased by 20 mg weekly. SUBJECTS AND METHODS The study included 15 subjects (eight males), with a median age of 58 years (range 35-80) on combination therapy of high-dose LA-SSAs and weekly PEGV for >6 months, and IGF1 levels within the normal range. Treatment efficacy was assessed by measuring serum IGF1 levels. RESULTS After 12 months of weekly PEGV monotherapy, serum IGF1 levels of 73% of the subjects remained controlled. In one patient, LA-SSA had to be restarted due to recurrence of headache. IGF1 levels increased from a baseline level of 0.62 × ULN (range 0.30-0.84) to 0.83 × ULN (0.30-1.75) after 12 months, while the median weekly PEGV dose increased from 60 (30-80) mg to 80 (50-120) mg. CONCLUSION Our results suggest that switching from combination therapy of LA-SSAs and PEGV to PEGV monotherapy can be a viable treatment option for acromegaly patients without compromising efficacy.
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Affiliation(s)
- A Muhammad
- Endocrinology SectionDepartment of Medicine, Pituitary Center Rotterdam, Erasmus University Medical Center, Rotterdam, The Netherlands
| | - A J van der Lely
- Endocrinology SectionDepartment of Medicine, Pituitary Center Rotterdam, Erasmus University Medical Center, Rotterdam, The Netherlands
| | - R D O'Connor
- Endocrinology SectionDepartment of Medicine, Pituitary Center Rotterdam, Erasmus University Medical Center, Rotterdam, The Netherlands
| | - P J Delhanty
- Endocrinology SectionDepartment of Medicine, Pituitary Center Rotterdam, Erasmus University Medical Center, Rotterdam, The Netherlands
| | - J Dal
- Medical Department (Endocrinology and Diabetes)Medical Research Laboratories, Clinical Institute, Aarhus, Denmark
| | - A H Dallenga
- Endocrinology SectionDepartment of Medicine, Pituitary Center Rotterdam, Erasmus University Medical Center, Rotterdam, The Netherlands
| | - R A Feelders
- Endocrinology SectionDepartment of Medicine, Pituitary Center Rotterdam, Erasmus University Medical Center, Rotterdam, The Netherlands
| | - J A M J L Janssen
- Endocrinology SectionDepartment of Medicine, Pituitary Center Rotterdam, Erasmus University Medical Center, Rotterdam, The Netherlands
| | - J O L Jorgensen
- Medical Department (Endocrinology and Diabetes)Medical Research Laboratories, Clinical Institute, Aarhus, Denmark
| | - S J C M M Neggers
- Endocrinology SectionDepartment of Medicine, Pituitary Center Rotterdam, Erasmus University Medical Center, Rotterdam, The Netherlands
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12
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Dogo-Isonagie C, Lee SL, Lohith K, Liu H, Mandadapu SR, Lusvarghi S, O'Connor RD, Bewley CA. Design and synthesis of small molecule-sulfotyrosine mimetics that inhibit HIV-1 entry. Bioorg Med Chem 2016; 24:1718-28. [PMID: 26968647 PMCID: PMC7261409 DOI: 10.1016/j.bmc.2016.02.044] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2016] [Revised: 02/22/2016] [Accepted: 02/28/2016] [Indexed: 02/01/2023]
Abstract
In the absence of a cure or vaccine for HIV/AIDS, small molecule inhibitors remain an attractive choice for antiviral therapeutics. Recent structural and functional studies of the HIV-1 surface envelope glycoprotein gp120 have revealed sites of vulnerability that can be targeted by small molecule and peptide inhibitors, thereby inhibiting HIV-1 infection. Here we describe a series of small molecule entry inhibitors that were designed to mimic the sulfated N-terminal peptide of the HIV-1 coreceptor CCR5. From a panel of hydrazonothiazolyl pyrazolinones, we demonstrate that compounds containing naphthyl di- and tri-sulfonic acids inhibit HIV-1 infection in single round infectivity assays with the disulfonic acids being the most potent. Molecular docking supports the observed structure activity relationship, and SPR confirmed binding to gp120. In infectivity assays treatment with a representative naphthyl disulfonate and a disulfated CCR5 N-terminus peptide results in competitive inhibition, with combination indices >2. In total this work shows that gp120 and HIV-1 infection can be inhibited by small molecules that mimic the function of, and are competitive with the natural sulfated CCR5 N-terminus.
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Affiliation(s)
- Cajetan Dogo-Isonagie
- Laboratory of Bioorganic Chemistry, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892-0820, United States
| | - Su-Lin Lee
- Laboratory of Bioorganic Chemistry, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892-0820, United States
| | - Katheryn Lohith
- Laboratory of Bioorganic Chemistry, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892-0820, United States
| | - Hongbing Liu
- Laboratory of Bioorganic Chemistry, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892-0820, United States
| | - Sivakoteswara R Mandadapu
- Laboratory of Bioorganic Chemistry, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892-0820, United States
| | - Sabrina Lusvarghi
- Laboratory of Bioorganic Chemistry, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892-0820, United States
| | - Robert D O'Connor
- Laboratory of Bioorganic Chemistry, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892-0820, United States
| | - Carole A Bewley
- Laboratory of Bioorganic Chemistry, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892-0820, United States.
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13
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O'Connor RD, Xu J, Ewald GA, Ackerman JJH, Peterson LR, Gropler RJ, Bashir A. Intramyocardial triglyceride quantification by magnetic resonance spectroscopy: In vivo and ex vivo correlation in human subjects. Magn Reson Med 2011; 65:1234-8. [PMID: 21500254 DOI: 10.1002/mrm.22734] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2010] [Revised: 09/28/2010] [Accepted: 10/27/2010] [Indexed: 01/21/2023]
Abstract
Accumulation of triglycerides (TG) in heart tissue has been associated with changes in left ventricular function. Proton magnetic resonance spectroscopy is currently the only noninvasive in vivo method to measure myocardial triglycerides content. The primary aim of this study was to determine if these in vivo measurements are specific to myocardial triglycerides in human subjects. Thus, in vivo proton magnetic resonance spectroscopy measurements were conducted on orthotopic heart transplant patients (n = 8) immediately before they underwent routine biopsies and ex vivo measurements were made on the endomyocardial biopsy samples. The correlation coefficient between the two measurements was 0.97, with P < 0.005, demonstrating for the first time the specificity of the in vivo measurement in human heart. From accompanying reliability experiments, the standardized typical error for the in vivo proton magnetic resonance spectroscopy method was estimated to be 7.0%, with a 95% confidence interval from 5.5 to 9.4%. These results suggest that proton magnetic resonance spectroscopy provides a specific and reliable measurement of myocardial triglycerides content and is suitable for routine studies.
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Affiliation(s)
- Robert D O'Connor
- Mallinckrodt Institute of Radiology, Washington University School of Medicine, St Louis, Missouri, USA.
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14
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Abstract
We present a new method that integrates selective biosynthetic labeling and solid-state NMR detection to identify in situ important protein cross-links in plant cell walls. We have labeled soybean cells by growth in media containing l-[ring-d(4)]tyrosine and l-[ring-4-(13)C]tyrosine, compared whole-cell and cell-wall (13)C CPMAS spectra, and examined intact cell walls using (13)C{(2)H} rotational echo double-resonance (REDOR) solid-state NMR. The proximity of (13)C and (2)H labels shows that 25% of the tyrosines in soybean cell walls are part of isodityrosine cross-links between protein chains. We also used (15)N{(13)C} REDOR of intact cell walls labeled by l-[ε-(15)N,6-(13)C]lysine and depleted in natural-abundance (15)N to establish that the side chains of lysine are not significantly involved in covalent cross-links to proteins or sugars.
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Affiliation(s)
- Lynette Cegelski
- Department of Chemistry, Washington University, St. Louis, Missouri 63130, United States.
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15
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O'Connor RD, Bashir A, Cade WT, Yarasheski KE, Gropler RJ. 1H-magnetic resonance spectroscopy for quantifying myocardial lipid content in humans with the cardiometabolic syndrome. J Clin Hypertens (Greenwich) 2010; 11:528-32. [PMID: 19751469 DOI: 10.1111/j.1559-4572.2009.00061.x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Affiliation(s)
- Robert D O'Connor
- Department of Radiology, Washington University School of Medicine, St Louis, MO 63110, USA.
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16
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Abstract
Chain packing in homogeneous blends of carbonate (13)C-labeled bisphenol A polycarbonate with either (i) CF(3)-labeled bisphenol A polycarbonate or (ii) ring-F-labeled bisphenol A polycarbonate has been characterized using (13)C{(19)F} rotational-echo double-resonance (REDOR) nuclear magnetic resonance. In both blends, the (13)C observed spin was at high concentration, and the (19)F dephasing or probe spin was at low concentration. In this situation, an analysis in terms of a distribution of isolated heteronuclear pairs of spins is valid. Nearest-neighbor separation of (13)C and (19)F labels was determined by accurately mapping the initial dipolar evolution using a shifted-pulse version of REDOR. Based on the results of this experiment, the average distance from a ring-fluorine to the nearest (13)C=O is more than 1.2 A greater than the corresponding CF(3)-(13)C=O distance. Next-nearest and more-distant-neighbor separations of labels were measured in a 416-rotor-cycle constant-time version of REDOR for both blends. Statistically significant local order was established for the nearest-neighbor labels in the methyl-labeled blend. These interchain packing results are in qualitative agreement with predictions based on coarse-grained simulations of a specially adapted model for bisphenol A polycarbonate. The model itself has been previously used to determine static and dynamic properties of polycarbonate with results in good agreement with those from rheological and neutron scattering experiments.
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Affiliation(s)
- Dirk Stueber
- Department of Chemistry, Washington University, St. Louis, Missouri 63130, USA
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17
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O'Connor RD, Zayzafoon M, Farach-Carson MC, Schanen NC. Mecp2 deficiency decreases bone formation and reduces bone volume in a rodent model of Rett syndrome. Bone 2009; 45:346-56. [PMID: 19414073 PMCID: PMC2739100 DOI: 10.1016/j.bone.2009.04.251] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/02/2008] [Revised: 03/25/2009] [Accepted: 04/24/2009] [Indexed: 01/03/2023]
Abstract
Rett syndrome (RTT), a neurological disorder characterized by neurological impairment and a high frequency of osteopenia which often manifests early in childhood, most often is caused by inactivating mutations in the X-linked gene encoding a regulator of epigenetic gene expression, methyl CpG binding protein, MeCP2. Clinical data show that, along with neurological defects, females with RTT frequently have marked decreases in bone mineral density (BMD) beyond that expected from disuse atrophy. To investigate the relationship between loss of Mecp2 and reduced BMD, we used a Mecp2 null mouse model, Mecp2 (-/yBIRD), for our histological and biochemical studies. Mecp2 (-/yBIRD) mice have significantly shorter femurs and an overall reduced skeletal size compared to wild-type mice by post-natal day 60 (P60). Histological and histomorphometric studies identified growth plate abnormalities as well as decreased cortical and trabecular bone in P21 and especially in P60 Mecp2 (-/yBIRD) mice. Dynamic histomorphometry revealed decreased mineral apposition rates (MAR) in Mecp2 null femoral trabecular bone as well as in calvarial bone samples. While changes in MAR of cortical bone were not significant, loss of Mecp2 significantly reduced cortical, trabecular and calvarial bone volume compared with age-matched wild-type animals. These differences indicate that Mecp2 deficiency leads to osteoblast dysfunction, which translates into reduced osteoid deposition accounting for the reduced bone volume phenotype. While individual variations were observed in OPG and Rankl concentrations, molar ratios of OPG:Rankl at P21 and P60 were comparable between wild-type and Mecp2 (-/yBIRD) mice and showed a consistent excess of OPG. In tibial sections, TRAP staining demonstrated equivalent osteoclast number per bone surface measurements between wild-type and null animals. Our work with a Mecp2 null mouse model suggests epigenetic regulation of bone in the Mecp2 (-/yBIRD) mice which is associated with decreased osteoblast activity rather than increased osteoclastic bone loss.
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Affiliation(s)
- R D O'Connor
- Department of Biological Sciences, University of Delaware, Newark, DE 19716, USA
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18
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Yu TY, O'Connor RD, Sivertsen AC, Chiauzzi C, Poliks B, Fischer M, Bacher A, Haase I, Cushman M, Schaefer J. (15)N{(31)P} REDOR NMR studies of the binding of phosphonate reaction intermediate analogues to Saccharomyces cerevisiae lumazine synthase. Biochemistry 2008; 47:13942-51. [PMID: 19117095 PMCID: PMC2630582 DOI: 10.1021/bi8015789] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Lumazine synthase catalyzes the reaction of 5-amino-6-D-ribitylamino-2,4(1H,3H)-pyrimidinedione(1) with (S)-3,4-dihydroxybutanone 4-phosphate (2) to afford 6,7-dimethyl-8-D-ribityllumazine(3), the immediate biosynthetic precursor of riboflavin. The overall reaction implies a series of intermediates that are incompletely understood. The 15N{31P} REDOR NMR spectra of three metabolically stable phosphonate reaction intermediate analogues complexed to Saccharomyces cereVisiae lumazine synthase have been obtained at 7 and 12 T. Distances from the phosphorus atoms of the ligands to the side chain nitrogens of Lys92, His97, Arg136, and His148 have been determined. These distances were used in combination with the X-ray crystal coordinates of one of the intermediate analogues complexed with the enzyme in a series of distance-restrained molecular dynamics simulations. The resulting models indicate mobility of the Lys92 side chain, which could facilitate the exchange of inorganic phosphate eliminated from the substrate in one reaction, with the organic phosphate-containing substrate necessary for the next reaction.
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Affiliation(s)
| | | | | | | | | | | | | | | | - Mark Cushman
- To whom correspondence should be addressed. Mark Cushman, phone: 765-494-1465; fax: 765-494-6790, e-mail . Jacob Schaefer, phone: 314 935 6844; fax: 314-935-4481; e-mail: .
| | - Jacob Schaefer
- To whom correspondence should be addressed. Mark Cushman, phone: 765-494-1465; fax: 765-494-6790, e-mail . Jacob Schaefer, phone: 314 935 6844; fax: 314-935-4481; e-mail: .
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19
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O'Connor RD, Gropler RJ, Peterson L, Schaffer J, Ackerman JJH. Limits of a localized magnetic resonance spectroscopy assay for ex vivo myocardial triacylglycerol. J Pharm Biomed Anal 2007; 45:382-9. [PMID: 17931816 DOI: 10.1016/j.jpba.2007.08.022] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2007] [Revised: 08/27/2007] [Accepted: 08/29/2007] [Indexed: 01/15/2023]
Abstract
Localized magnetic resonance spectroscopy (LMRS) promises a powerful non-invasive means to determine myocardial triacylglycerol (TAG) in a clinical setting. Here, the linearity, specificity, robustness, precision, and accuracy of an ex vivo mouse-heart LMRS TAG assay are assessed by quantifying the spatial, spectral, and relaxation-induced uncertainties. The protocol, which is based on localization by adiabatic selective refocusing (LASER) using frequency offset corrected inversion (FOCI) pulses, alternating gradient polarity, and simple post-processing, is shown to have good characteristics. The presented protocol has a benchmark, phantom-based, accuracy of 3%, and when applied to ex vivo mouse hearts the accuracy is 6%, making the LMRS assay comparable to the typical destructive bioanalytical assay.
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Affiliation(s)
- Robert D O'Connor
- Department of Radiology, Washington University, Saint Louis, MO 63110, USA
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20
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Paik Y, Yang C, Metaferia B, Tang S, Bane S, Ravindra R, Shanker N, Alcaraz AA, Johnson SA, Schaefer J, O'Connor RD, Cegelski L, Snyder JP, Kingston DGI. Rotational-echo double-resonance NMR distance measurements for the tubulin-bound Paclitaxel conformation. J Am Chem Soc 2007; 129:361-70. [PMID: 17212416 PMCID: PMC2432525 DOI: 10.1021/ja0656604] [Citation(s) in RCA: 68] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The important anticancer drug Taxol (paclitaxel, PTX) owes its unique activity to its ability to bind to tubulin in a stoichiometric ratio and promote its assembly into microtubules. The conformation of the microtubule-bound drug has been the focus of numerous research efforts, since the inability of polymerized tubulin to form crystals precludes structure proof by X-ray crystallography. Likewise, although the alpha,beta-tubulin dimer structure has been solved by electron crystallography, the 3.7 A resolution is too low to permit direct determination of either ligand conformation or binding pose. In this article, we present experimental results from 2H{19F} REDOR NMR that provide direct confirmation that paclitaxel adopts a T-shaped conformation when it is bound to tubulin.
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Affiliation(s)
- Younkee Paik
- Department of Chemistry, M/C 0212, Virginia Polytechnic Institute and State University, Blacksburg, Virginia 24061, USA
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21
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Cegelski L, Rice CV, O'Connor RD, Caruano AL, Tochtrop GP, Cai ZY, Covey DF, Schaefer J. Mapping the locations of estradiol and potent neuroprotective analogues in phospholipid bilayers by REDOR. Drug Dev Res 2006. [DOI: 10.1002/ddr.20048] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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22
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Toke O, O'Connor RD, Weldeghiorghis TK, Maloy WL, Glaser RW, Ulrich AS, Schaefer J. Structure of (KIAGKIA)3 aggregates in phospholipid bilayers by solid-state NMR. Biophys J 2004; 87:675-87. [PMID: 15240501 PMCID: PMC1304391 DOI: 10.1529/biophysj.103.032714] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2003] [Accepted: 03/04/2004] [Indexed: 11/18/2022] Open
Abstract
The interchain (13)C-(19)F dipolar coupling measured in a rotational-echo double-resonance (REDOR) experiment performed on mixtures of differently labeled KIAGKIA-KIAGKIA-KIAGKIA (K3) peptides (one specifically (13)C labeled, and the other specifically (19)F labeled) in multilamellar vesicles of dipalmitoylphosphatidylcholine and dipalmitoylphosphatidylglycerol (1:1) shows that K3 forms close-packed clusters, primarily dimers, in bilayers at a lipid/peptide molar ratio (L/P) of 20. Dipolar coupling to additional peptides is weaker than that within the dimers, consistent with aggregates of monomers and dimers. Analysis of the sideband dephasing rates indicates a preferred orientation between the peptide chains of the dimers. The combination of the distance and orientation information from REDOR is consistent with a parallel (N-N) dimer structure in which two K3 helices intersect at a cross-angle of approximately 20 degrees. Static (19)F NMR experiments performed on K3 in oriented lipid bilayers show that between L/P = 200 and L/P = 20, K3 chains change their absolute orientation with respect to the membrane normal. This result suggests that the K3 dimers detected by REDOR at L/P = 20 are not on the surface of the bilayer but are in a membrane pore.
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Affiliation(s)
- Orsolya Toke
- Department of Chemistry, Washington University, St. Louis, Missouri 63130, USA
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23
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McDowell LM, Studelska DR, Poliks B, O'Connor RD, Schaefer J. Characterization of the Complex of a Trifluoromethyl-Substituted Shikimate-Based Bisubstrate Inhibitor and 5-Enolpyruvylshikimate-3-phosphate Synthase by REDOR NMR. Biochemistry 2004; 43:6606-11. [PMID: 15157093 DOI: 10.1021/bi049685w] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
A combination of (15)N[(19)F], (31)P[(15)N], and (31)P[(19)F] rotational-echo double-resonance NMR has been used to characterize the conformation of a bound trifluoromethylketal, shikimate-based bisubstrate inhibitor of 5-enolpyruvylshikimate-3-phosphate synthase. The solid-state NMR experiments were performed on the complex formed in solution and then lyophilized at low temperatures in the presence of stabilizing lyoprotectants. The results of these experiments indicate that none of the side chains of the six arginines that surround the active site forms a compact salt bridge with the phosphate groups of the bound inhibitor.
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Affiliation(s)
- Lynda M McDowell
- Department of Chemistry, Washington University, St. Louis, Missouri 63130, USA
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24
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McDowell LM, Poliks B, Studelska DR, O'Connor RD, Beusen DD, Schaefer J. Rotational-echo double-resonance NMR-restrained model of the ternary complex of 5-enolpyruvylshikimate-3-phosphate synthase. J Biomol NMR 2004; 28:11-29. [PMID: 14739636 DOI: 10.1023/b:jnmr.0000012864.70184.48] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
The 46-kD enzyme 5-enolpyruvylshikimate-3-phosphate (EPSP) synthase catalyzes the condensation of shikimate-3-phosphate (S3P) and phosphoenolpyruvate to form EPSP. The reaction is inhibited by N-(phosphonomethyl)-glycine (Glp), which, in the presence of S3P, binds to EPSP synthase to form a stable ternary complex. We have used solid-state NMR and molecular modeling to characterize the EPSP synthase-S3P-Glp ternary complex. Modeling began with the crystal coordinates of the unliganded protein, published distance restraints, and information from the chemical modification and mutagenesis literature on EPSP synthase. New inter-ligand and ligand-protein distances were obtained. These measurements utilized the native (31)P in S3P and Glp, biosynthetically (13)C-labeled S3P, specifically (13)C and (15)N labeled Glp, and a variety of protein-(15)N labels. Several models were investigated and tested for accuracy using the results of both new and previously published rotational-echo double resonance (REDOR) NMR experiments. The REDOR model is compared with the recently published X-ray crystal structure of the ternary complex, PDB code 1G6S. There is general agreement between the REDOR model and the crystal structure with respect to the global folding of the two domains of EPSP synthase and the relative positioning of S3P and Glp in the binding pocket. However, some of the REDOR data are in disagreement with predictions based on the coordinates of 1G6S, particularly those of the five arginines lining the binding site. We attribute these discrepancies to substantive differences in sample preparation for REDOR and X-ray crystallography. We applied the REDOR restraints to the 1G6S coordinates and created a REDOR-refined xray structure that agrees with the NMR results.
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Affiliation(s)
- Lynda M McDowell
- Department of Chemistry, Washington University, One Brookings Drive, St. Louis, MO 63130, U.S.A.
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25
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McMillan HM, Salman R, Khan MF, McAnena O, O'Connor RD. An ominous inguinal hernia. Ir J Med Sci 2004; 173:57. [PMID: 15732240 DOI: 10.1007/bf02914528] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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26
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Studelska DR, McDowell LM, Adler M, O'Connor RD, Mehta AK, Guilford WJ, Dallas JL, Arnaiz D, Light DR, Schaefer J. Conformation of a bound inhibitor of blood coagulant factor Xa. Biochemistry 2003; 42:7942-9. [PMID: 12834346 DOI: 10.1021/bi027369g] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
13C[(15)N] and (13)C[(19)F] rotational-echo double-resonance NMR have been used to characterize the enzyme-bound structure of ZK-816042, an amidine-imidazoline inhibitor of human factor Xa (FXa). The NMR experiments were performed on a lyophilized FXa-inhibitor complex. The complex was formed in solution in the presence of stabilizing excipients and frozen after gradual supercooling prior to lyophilization. The results indicate that the inhibitor binds with a distribution of orientations of the imidazoline ring.
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Affiliation(s)
- Daniel R Studelska
- Department of Chemistry, Washington University, St. Louis, Missouri 63130, USA
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27
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Abstract
REDOR and REDOR-like 13C[19F] and 2H[19F] NMR experiments have been performed on lyophilized whole cells of Staphylococcus aureus. The bacteria were grown to maturity on media containing L-[13C(3)]alanine or L-[methyl-d(3)]alanine, and then complexed with the 4-fluorobiphenyl derivative of chloroeremomycin, an analogue of the widely used antibiotic, vancomycin. The position of the 19F of the drug bound in the bacterial cell wall was determined relative to L-alanine 13C and 2H labels in the peptidoglycan peptide stem that was closest to the fluorinated biphenyl moiety of the drug. These determinations were made by dipolar recoupling methods that do not require an absolute measurement of the REDOR full echo (the signal observed without rotor-synchronized dephasing pulses) of the labels in the peptide stem.
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Affiliation(s)
- Anil K Mehta
- Department of Chemistry, Washington University, One Brookings Dr., Campus Box 1134, St. Louis, MO 63130, USA
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28
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McDowell LM, McCarrick MA, Studelska DR, O'Connor RD, Light DR, Guilford WJ, Arnaiz D, Adler M, Dallas JL, Poliks B, Schaefer J. Human factor Xa bound amidine inhibitor conformation by double rotational-echo double resonance nuclear magnetic resonance and molecular dynamics simulations. J Med Chem 2003; 46:359-63. [PMID: 12540235 DOI: 10.1021/jm0202324] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Double rotational-echo double resonance (double REDOR) NMR was used to investigate the conformation of a (13)C-, (15)N-, and (19)F-labeled inhibitor (Berlex Biosciences compound no. ZK-806299) bound to human factor Xa. Conformationally dependent carbon-fluorine dipolar couplings were measured by (13)C[(19)F] REDOR. Natural abundance carbon signals in the full-echo spectra were removed by (13)C[(15)N] REDOR. Major and minor binding modes were suggested by the NMR data, but only the former had adequate signal to noise for distance determinations. Molecular dynamics simulations restrained by double-REDOR-determined intramolecular (13)C-(19)F distances revealed two models for the dominant binding mode that are consistent with the NMR data. We conclude that ZK-806299 binds similarly to both FXa. Moreover, it appears to bind to FXa in a fashion previously demonstrated for ZK-807834, a more selective FXa inhibitor.
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Affiliation(s)
- Lynda M McDowell
- Department of Chemistry, Washington University, One Brookings Drive, St. Louis, Missouri 63130, USA.
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29
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Cegelski L, Kim SJ, Hing AW, Studelska DR, O'Connor RD, Mehta AK, Schaefer J. Rotational-echo double resonance characterization of the effects of vancomycin on cell wall synthesis in Staphylococcus aureus. Biochemistry 2002; 41:13053-8. [PMID: 12390033 DOI: 10.1021/bi0202326] [Citation(s) in RCA: 61] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Cross-polarization magic-angle spinning and rotational-echo double resonance 13C and 15N NMR experiments have been performed on intact cells of Staphylococcus aureus labeled with D-[1-13C]alanine and [15N]glycine or with [1-13C]glycine and L-[epsilon-15N]lysine. The cells were harvested during stationary or exponential growth conditions, the latter in media with and without the addition of vancomycin. The results of these experiments allowed the in situ determination of the relative concentrations of peptidoglycan cross-links (the number of peptide-stem D-alanines covalently linked to a pentaglycyl bridge) and bridge-links (the number of peptide-stem lysines covalently linked to a pentaglycyl bridge). The concentration of cross-links remained constant in the presence of vancomycin, whereas the number of bridge-links decreased. These changes suggest that vancomycin (at therapeutic levels) interrupts peptidoglycan synthesis in S. aureus by interference with transglycosylation.
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Affiliation(s)
- Lynette Cegelski
- Department of Chemistry, Washington University, St. Louis, Missouri 63110, USA
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Kim SJ, Cegelski L, Studelska DR, O'Connor RD, Mehta AK, Schaefer J. Rotational-echo double resonance characterization of vancomycin binding sites in Staphylococcus aureus. Biochemistry 2002; 41:6967-77. [PMID: 12033929 DOI: 10.1021/bi0121407] [Citation(s) in RCA: 68] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Solid-state NMR experiments with stable isotope-labeled Staphylococcus aureus have provided insight into the structure of the peptidoglycan binding site of a potent fluorobiphenyl derivative of chloroeremomycin (Eli Lilly LY329332). Rotational-echo double resonance (REDOR) NMR provided internuclear distances from the 19F of this glycopeptide antibiotic to natural-abundance 31P and to specific 13C and 15N labels biosynthetically incorporated into the bacteria from labeled alanine, glycine, or lysine in the growth medium. Results from experiments with intact late log phase bacteria and cell walls indicated homogeneous drug-peptidoglycan binding. Drug dimers were not detected in situ, and the hydrophobic fluorobiphenyl group of LY329332 did not insert into the bilayer membrane. A model of the binding site consistent with the REDOR results positions the vancomycin cleft around an un-cross-linked D-Ala-D-Ala peptide stem with the fluorobiphenyl moiety of the antibiotic near the base of a second, proximate stem in a locally ordered peptidoglycan matrix.
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Affiliation(s)
- Sung Joon Kim
- Department of Molecular Biophysics, Washington University School of Medicine, St. Louis, Missouri 63130, USA
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Affiliation(s)
- Robert D. O'Connor
- Department of Chemistry, Washington University, St. Louis, Missouri 63130, and Department of Chemistry, University of Illinois, Urbana, Illinois 61801
| | - Jeffery A. Byers
- Department of Chemistry, Washington University, St. Louis, Missouri 63130, and Department of Chemistry, University of Illinois, Urbana, Illinois 61801
| | - William D. Arnold
- Department of Chemistry, Washington University, St. Louis, Missouri 63130, and Department of Chemistry, University of Illinois, Urbana, Illinois 61801
| | - Eric Oldfield
- Department of Chemistry, Washington University, St. Louis, Missouri 63130, and Department of Chemistry, University of Illinois, Urbana, Illinois 61801
| | - Karen L. Wooley
- Department of Chemistry, Washington University, St. Louis, Missouri 63130, and Department of Chemistry, University of Illinois, Urbana, Illinois 61801
| | - Jacob Schaefer
- Department of Chemistry, Washington University, St. Louis, Missouri 63130, and Department of Chemistry, University of Illinois, Urbana, Illinois 61801
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O'Connor RD, Poliks B, Bolton DH, Goetz JM, Byers JA, Wooley KL, Schaefer J. Chain Packing in Linear Phenol−Polycarbonate by 13C{2H} REDOR. Macromolecules 2002. [DOI: 10.1021/ma010919i] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Robert D. O'Connor
- Department of Chemistry, Washington University, St. Louis, Missouri 63130, and Department of Physics, Binghamton University, Binghamton, New York 13902
| | - Barbara Poliks
- Department of Chemistry, Washington University, St. Louis, Missouri 63130, and Department of Physics, Binghamton University, Binghamton, New York 13902
| | - Daniel H. Bolton
- Department of Chemistry, Washington University, St. Louis, Missouri 63130, and Department of Physics, Binghamton University, Binghamton, New York 13902
| | - Jon M. Goetz
- Department of Chemistry, Washington University, St. Louis, Missouri 63130, and Department of Physics, Binghamton University, Binghamton, New York 13902
| | - Jeffery A. Byers
- Department of Chemistry, Washington University, St. Louis, Missouri 63130, and Department of Physics, Binghamton University, Binghamton, New York 13902
| | - Karen L. Wooley
- Department of Chemistry, Washington University, St. Louis, Missouri 63130, and Department of Physics, Binghamton University, Binghamton, New York 13902
| | - Jacob Schaefer
- Department of Chemistry, Washington University, St. Louis, Missouri 63130, and Department of Physics, Binghamton University, Binghamton, New York 13902
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Abstract
Algebraic expressions are given for the sideband intensities of REDOR dephasing experiments as a function of the relative orientation of the CSA and dipolar tensors. The expressions are straightforward to derive and implement and can be easily modified for variations in the spin systems, including distributions of distances and multiple dephasers. These expressions, along with the high sensitivity, resolution, and general robust nature of REDOR, make determining CSA-dipolar orientations from REDOR experiments reliable and, compared to full simulations, efficient and routine. Additionally, it is shown that even the +/-1 sidebands of fast-spinning samples may contain significant information about orientation. Finally, numerical integration of the expressions supports the intuitive notion that any difference in the sideband dephasing rates is evidence of preferred CSA-dipolar orientations. This fact can be used to gauge the extent of local molecular order in intermolecular dephasing experiments.
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Affiliation(s)
- Robert D O'Connor
- Department of Chemistry, Washington University, St. Louis, Missouri 63130, USA
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Kao HM, O'Connor RD, Mehta AK, Huang H, Poliks B, Wooley KL, Schaefer J. Location of Cholic Acid Sequestered by Core−Shell Nanoparticles Using REDOR NMR. Macromolecules 2001. [DOI: 10.1021/ma001429d] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Hsien-Ming Kao
- Department of Chemistry, Washington University, St. Louis, Missouri 63130
| | - Robert D. O'Connor
- Department of Chemistry, Washington University, St. Louis, Missouri 63130
| | - Anil K. Mehta
- Department of Chemistry, Washington University, St. Louis, Missouri 63130
| | - Haiyong Huang
- Department of Chemistry, Washington University, St. Louis, Missouri 63130
| | - Barbara Poliks
- Department of Chemistry, Washington University, St. Louis, Missouri 63130
| | - Karen L. Wooley
- Department of Chemistry, Washington University, St. Louis, Missouri 63130
| | - Jacob Schaefer
- Department of Chemistry, Washington University, St. Louis, Missouri 63130
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Legorreta AP, Christian-Herman J, O'Connor RD, Hasan MM, Evans R, Leung KM. Compliance with national asthma management guidelines and specialty care: a health maintenance organization experience. Arch Intern Med 1998; 158:457-64. [PMID: 9508223 DOI: 10.1001/archinte.158.5.457] [Citation(s) in RCA: 243] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Abstract
BACKGROUND To improve asthma disease management, the National Asthma Education Program (NAEP) Expert Panel published Guidelines for the Diagnosis and Management of Asthma in 1991. OBJECTIVES To compare the current status of asthma disease management among patients in a large health maintenance organization with the NAEP guidelines and to identify the factors that may be associated with medical care (eg, emergency department visits and hospital admissions) and adherence to the guidelines. METHODS Analyses of 1996 survey data from 5580 members with asthma (age range, 14 to 65 years) covered by a major health maintenance organization in California (Health Net). RESULTS In general, adherence to NAEP guidelines was poor. Seventy-two percent of respondents with severe asthma reported having a steroid inhaler, and of those, only 54% used it daily. Only 26% of respondents reported having a peak flowmeter, and of those, only 16% used it daily. Age (older), duration of asthma (longer), increasing current severity of disease, and treatment by an asthma specialist correlated with daily use of inhaled steroids. Ethnicity (African American and Hispanic) correlated negatively with inhaled steroid use but positively with emergency department visits and hospital admissions for asthma. Increasing age and treatment by an asthma specialist were also identified as common factors significantly related to the daily use of a peak flowmeter and, interestingly, to overuse of beta2-agonist metered-dose inhalers. CONCLUSIONS Although the NAEP guidelines were published 7 years ago, compliance with the guidelines was low. It was especially poor for use of preventive medication and routine peak-flow measurement. Furthermore, the results showed that asthma specialists provided more thorough care than did primary care physicians in treating patients with asthma. Combining the results of the regression analyses revealed that some of the variation in rates of emergency department visits and hospitalizations among some subpopulations can be explained by the underuse of preventive medication. This study serves the goal of documenting the quality of care and services currently provided to patients with asthma through a large health maintenance organization and provides baseline information that can be used to design and assess effective population-based asthma disease management intervention programs.
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Affiliation(s)
- A P Legorreta
- Quality Initiatives Division, Health Net, Woodland Hills, CA 91637, USA
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Moreland LW, Heck LW, Koopman WJ, Saway PA, Adamson TC, Fronek Z, O'Connor RD, Morgan EE, Diveley JP, Richieri SP, Carlo DJ, Brostoff SW. V beta 17 T cell receptor peptide vaccination in rheumatoid arthritis: results of phase I dose escalation study. J Rheumatol Suppl 1996; 23:1353-62. [PMID: 8856613] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
OBJECTIVE To determine whether modulation of activated T cells occurs in patients with rheumatoid arthritis (RA) after immunization with T cell receptor (TCR) V beta 17 peptides, a phase I trial was initiated to investigate the safety and feasibility of TCR peptide immunization as a therapeutic approach in RA. METHODS 15 patients with moderate to severe RA were given an intramuscular injection of one of 4 doses (10, 30, 100, and 300 micrograms) of the V beta 17 peptide vaccination, followed by a booster injection of the same dose of vaccine 3 weeks later. Patients were followed for 48 weeks. RESULTS The product was well tolerated and no serious adverse events attributable to the vaccine were observed. This was an uncontrolled phase I trial, however; decreases in patients joint scores were observed at all followup visits starting at 4 weeks after primary immunization. Activated V beta 17 T cells (IL-2R+) in peripheral blood were decreased (> or = 20%) in 3/5 patients in the 100 micrograms group after initial measurement at Week 2 and 3/4 patients in the 300 micrograms group 3 weeks after immunization. Lymphocyte proliferation in response to the V beta 17 peptide was detected at 6 weeks or later after primary inoculation in 6/15 patients (40%) immunized. CONCLUSION Further controlled studies are required to assess the biologic and clinical efficacy of this treatment approach.
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Affiliation(s)
- L W Moreland
- Division of Clinical Immunology and Rheumatology, University of Alabama at Birmingham, USA
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Moreland LW, Heck LW, Koopman WJ, Saway PA, Adamson TC, Fronek Z, O'Connor RD, Morgan EE, Diveley JP, Chieffo NM. V beta 17 T-cell receptor peptide vaccine. Results of a phase I dose-finding study in patients with rheumatoid arthritis. Ann N Y Acad Sci 1995; 756:211-4. [PMID: 7645836 DOI: 10.1111/j.1749-6632.1995.tb44514.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Affiliation(s)
- L W Moreland
- University of Alabama at Birmingham 068 Spain Rehabilitation Center 35294-0006, USA
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Neuman TS, Bove AA, O'Connor RD, Kelsen SG. Asthma and diving. Ann Allergy 1994; 73:344-50. [PMID: 7944003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
BACKGROUND Approximately 10 to 15 million Americans are scuba divers. The prevalence of scuba diving and asthma makes it likely some asthmatics will be interested in scuba diving and some scuba divers will have asthma. Conditions present during scuba diving may provoke airway obstruction in asthmatic patients. Further, asthmatic patients may, in theory, face a greater than normal risk of pulmonary barotrauma from lung overdistension on ascent through the water column. OBJECTIVE The purpose of this paper is to review the theoretical issues underlying the prohibition against scuba diving for asthmatic patients as advanced by most major diving organizations in the United States and critically examine the relevant accident data. METHODS All reports that dealt with asthma and diving, and all available American accident data including both fatal and nonfatal accidents were reviewed. RESULTS Actuarial data on the risk of scuba accidents attributable to asthma do not define several important variables likely to affect accident risk during scuba diving. Despite these limitations, careful review indicates the risks of serious morbidity or mortality during scuba diving appears to be inconsequentially elevated in subjects whose asthma was not characterized. CONCLUSIONS Additional data are needed to define accurately risks of diving in subjects with different forms of asthma, however, the available data suggest asthmatic patients with normal airway function at rest, and with little airway reactivity in response to exercise or cold air inhalation, have a risk of pulmonary barotrauma similar to that of normal subjects.
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Affiliation(s)
- T S Neuman
- University of California, San Diego School of Medicine
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Hovell MF, Meltzer SB, Zakarian JM, Wahlgren DR, Emerson JA, Hofstetter CR, Leaderer BP, Meltzer EO, Zeiger RS, O'Connor RD. Reduction of environmental tobacco smoke exposure among asthmatic children: a controlled trial. Chest 1994; 106:440-6. [PMID: 7774317 DOI: 10.1378/chest.106.2.440] [Citation(s) in RCA: 107] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
STUDY OBJECTIVE This randomized clinical trial tested a behavioral medicine program designed to reduce asthmatic children's exposure to environmental tobacco smoke (ETS) in the home. DESIGN Families were randomly assigned to an experimental preventive medicine counseling group, a monitoring control group, or a usual treatment control group. Families were measured six times over 1 year. PARTICIPANTS Ninety-one families were recruited from four allergy clinics. INTERVENTION The experimental group received a 6-month series of counseling sessions designed to decrease ETS exposure. This group also monitored smoking, exposure, and children's asthma symptoms. The monitoring group did not receive counseling and the usual treatment control group received outcome measures only. MEASUREMENTS AND RESULTS Parents reported the daily number of cigarettes children were exposed to during the week preceding interviews. A nicotine air monitor and construct validity analysis confirmed the validity of exposure reports. Exposure to the parent's cigarettes in the home decreased for all groups. The experimental group attained a 79 percent decrease in children's ETS exposure, compared with 42 percent for the monitoring control and 34 percent for the usual treatment control group. Repeated-measures analysis of variance resulted in a significant (F([10,350] = 1.92, p < 0.05) group by time effect. At the final 12-month visit, the experimental/counseling group sustained a 51% decrease in children's exposure to cigarettes in the home from all smokers, while the monitoring control group showed an 18% decrease and the usual treatment control group a 15% decrease from pre-intervention [corrected]. CONCLUSION A behavioral medicine program was successful in reducing exposure to ETS in the home for these asthmatic children.
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Affiliation(s)
- M F Hovell
- Center for Behavioral Epidemiology, Graduate School of Public Health, San Diego State University, USA
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Willies-Jacobo LJ, Denson-Lino JM, Rosas A, O'Connor RD, Wilson NW. Socioeconomic status and allergy in children with asthma. J Allergy Clin Immunol 1993; 92:630-2. [PMID: 8409124] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Affiliation(s)
- L J Willies-Jacobo
- Department of Pediatrics, University of California San Diego, School of Medicine
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Denson-Lino JM, Willies-Jacobo LJ, Rosas A, O'Connor RD, Wilson NW. Effect of economic status on the use of house dust mite avoidance measures in asthmatic children. Ann Allergy 1993; 71:130-2. [PMID: 8346865] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
To assess the effect of socioeconomic status on compliance with house dust mite avoidance measures, we interviewed the parents of 60 mite-allergic, asthmatic children about mite avoidance. Thirty were of lower socioeconomic status and 30 were of higher socioeconomic status, as determined by the type of insurance. All had previously learned mite avoidance measures at the time of diagnosis. Twenty of 30 lower socioeconomic status parents had removed stuffed toys from the child's bedroom compared with only 12 of 30 higher socioeconomic status parents (P = .07). Twelve of 30 parents in the lower socioeconomic status group had obtained plastic mattress covers compared with 22 of the 30 higher socioeconomic status parents (P = .018). Eighteen parents in the lower socioeconomic status group expressed reasons for not obtaining plastic covers. Nine cited lack of funds, four did not know where to buy them, and four did not think it would help. Of the eight parents in the higher socioeconomic status group that did not obtain covers, six cited inconvenience and two thought it would not help. We conclude that education alone will not ensure compliance with house dust mite controls. Economic factors influence utilization. Access to free or low cost mite-proof pillow and mattress covers may improve asthma care for poor children.
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Affiliation(s)
- J M Denson-Lino
- Department of Pediatrics, U.C. School of Medicine, San Diego
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Spiegelberg HL, Falkoff RJ, O'Connor RD, Beck L. Interleukin-2 inhibits the interleukin-4-induced human IgE and IgG4 secretion in vivo. Clin Exp Immunol 1991; 84:400-5. [PMID: 1904325 PMCID: PMC1535428] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
The effect of interleukin-2 (IL-2) on IL-4-induced IgE and IgG4 secretion by B cells in peripheral blood mononuclear cell (PBMC) preparations from non-atopic healthy humans and atopic dermatitis patients was investigated. PBMC were cultured at an optimal concentration of recombinant IL-4 with or without addition of IL-2 for 10 days. Native and recombinant IL-2 inhibited the IL-4-induced IgE and IgG4 secretion in a dose-dependent manner by cells from both normal and atopic donors. Rabbit antibodies to IL-2 or to the monoclonal anti-IL-2 receptor antibody anti-TAC reversed the IL-2 effect. Culturing cells with IL-4 and IL-2 for 1 or 2 days only slightly suppressed the IgE and IgG4 secretion whereas addition of IL-2 to IL-4 containing cultures on day 4 or 5 inhibited the IgE and IgG4 secretion more effectively. This is in contrast to interferon-gamma (IFN-gamma) which inhibited the IL-4 induced IgE and IgG4 secretion when added for the first 24 or 48 h but had no effect when added on days 4 or 5. The data demonstrate that both IL-2 and IFN-gamma act as antagonists in the IL-4-induced IgE and IgG4 secretion by human B cells; while IL-2 appears to inhibit relatively late in culture, IFN-gamma has an early inhibitory effect, suggesting that the two lymphokines inhibit the IL-4 effect by different mechanisms.
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Affiliation(s)
- H L Spiegelberg
- Department of Immunology, Research Institute of Scripps Clinic, La Jolla, CA
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Spiegelberg HL, O'Connor RD, Falkoff RJ, Beck L. Interleukin-4 induced IgE and IgG4 secretion by B cells from atopic dermatitis patients. Int Arch Allergy Appl Immunol 1991; 94:181-3. [PMID: 1937871 DOI: 10.1159/000235357] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Peripheral blood mononuclear cells from 8 normals and 8 patients with atopic dermatitis (AD) were cultured with recombinant interleukin-4 (IL-4) and the IgE and IgG subclass levels in the culture supernatants measured by radioimmunoassays. IL-4 induced IgE and IgG4 secretion by B cells from both normals and AD patients whereas it has no consistent effect on IgG1, IgG2 and IgG3 secretion. The IL-4 dose response was similar for IgE and IgG4 secretion by cells from both normals and AD patients. On the average, the patients' cells secreted more IgE and less IgG4 than the cells from normals, but because of a large variation, the differences were not significant. However, the ratio of IgG4:IgE secretion was significantly greater for normals than AD patients (mean +/- SEM 7.1 +/- 1.6:1 vs. 1.5 +/- 0.4:1; p less than 0.01). The data demonstrate that IL-4 induces IgE and IgG4 secretion by B cells from both normals and AD patients and suggest that the IL-4 induced switch from IgM to IgG4 or IgE secretion may proceed preferentially to IgE in AD patients as compared to normals.
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Affiliation(s)
- H L Spiegelberg
- Department of Pediatrics, University of California, San Diego, La Jolla
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Zeiger RS, Heller S, Mellon MH, Forsythe AB, O'Connor RD, Hamburger RN, Schatz M. Effect of combined maternal and infant food-allergen avoidance on development of atopy in early infancy: a randomized study. J Allergy Clin Immunol 1989; 84:72-89. [PMID: 2754147 DOI: 10.1016/0091-6749(89)90181-4] [Citation(s) in RCA: 368] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
The effect of maternal and infant avoidance of allergenic foods on food allergy was examined in a prenatally randomized, controlled trial of infants of atopic parents. The diet of the prophylactic-treated group (N = 103) included (1) maternal avoidance of cow's milk, egg, and peanut during the third trimester of pregnancy and lactation and (2) infant use of casein hydrolysate (Nutramigen) for supplementation or weaning, and avoidance of solid foods for 6 months; cow's milk, corn, soy, citrus, and wheat, for 12 months; and egg, peanut, and fish, for 24 months. In the control group (N = 185), mothers had unrestricted diets, and infants followed American Academy of Pediatrics feeding guidelines. The cumulative prevalence of atopy was lower at 12 months in the prophylactic-treated (16.2%) compared to the control (27.1%) group (p = 0.039), resulting from reduced food-associated atopic dermatitis, urticaria and/or gastrointestinal disease by 12 months (5.1% versus 16.4%; p = 0.007), and any positive food skin test by 24 months (16.5% versus 29.4%; p = 0.019), caused primarily by fewer positive milk skin tests (1% versus 12.4%; p = 0.001). The prevalences of allergic rhinitis, asthma, and inhalant skin tests were unaffected. Serum IgE levels in the prophylactic-treated group were marginally lower only at 4 months. Thus, reduced exposure of infants to allergenic foods appeared to reduce food sensitization and allergy primarily during the first year of life.
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Affiliation(s)
- R S Zeiger
- Department of Allergy-Immunology Kaiser-Permanente Medical Center, San Diego 92111
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Hamburger RN, Casillas R, Johnson R, Mellon M, O'Connor RD, Zeiger R. Long-term studies in prevention of food allergy: patterns of IgG anti-cow's milk antibody responses. Ann Allergy 1987; 59:175-8. [PMID: 3688570] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Over the past 7 years we have enrolled several hundred families in a study of the prophylaxis of atopic allergy. Initially, control and study patients were at different institutions, but more recently a true double-blind random assignment to control or study group has been instituted. Nevertheless, all of the infants from these highly atopic families can be utilized to obtain the data reported; that is, the rate of change of IgE levels, the appearance of food sensitization (food-specific IgE), the signs and symptoms of atopic allergy diseases and the changes in cow's milk-specific IgG antibody during the first 2 years of life. Some aspects of the first three of these parameters have been presented in the eight references to this paper, but only preliminary data on the use of IgG anti-cow's milk antibody as a measure of compliance has been available. In this paper an analysis is presented of the various patterns of IgG antibody levels in the first 60 infants of the over 200 who have been studied to date. Both the age of onset and the subsequent changes in the foregoing immunologic measurements provide fundamental data with which to measure the success rate of any prophylactic or therapeutic regimen and may improve our capacity to predict the future course of infants and children with a strong familial tendency to allergy.
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Affiliation(s)
- R N Hamburger
- Pediatric Department, School of Medicine, University of California, San Diego, La Jolla
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Thompson LF, Ruedi JM, O'Connor RD, Bastian JF. Ecto-5'-nucleotidase expression during human B cell development. An explanation for the heterogeneity in B lymphocyte ecto-5'-nucleotidase activity in patients with hypogammaglobulinemia. The Journal of Immunology 1986. [DOI: 10.4049/jimmunol.137.8.2496] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Abstract
Ecto-5'-nucleotidase (ecto-5'-NT) activity was measured in human B cells at different stages of development. Ecto-5'-NT activity of B cell preparations from fetal spleen and cord blood was 5.08 and 5.59 +/- 2.8 nmol/hr/10(6) cells, respectively; that of B cell preparations from adult peripheral blood, spleen, or lymph node was fivefold to sixfold higher (27.9 +/- 12, 29.2 and 33.8 nmol/hr/10(6) cells, respectively). The increased enzyme activity in B cell preparations from adult peripheral blood as compared with cord blood paralleled increased percentages of 5'-NT+ cells (69 +/- 12% vs 32 +/- 17%) and an average of twice as much enzyme activity per positive cell. Small, resting B cells that cannot synthesize Ig in vitro in response to pokeweed mitogen (PWM) were isolated from adult peripheral blood by mouse erythrocyte rosetting. Total ecto-5'-NT activity and the percentage of 5'-NT+ cells were equivalent in total B cells and the mouse erythrocyte rosette-positive subpopulation. Thus, ecto-5'-NT activity is acquired before B cells gain the ability to differentiate into Ig-secreting plasma cells in response to PWM. Ecto-5'-NT activity was also measured in B cell preparations from eight patients with common variable immunodeficiency. Six had reduced ecto-5'-NT activity (2.83 to 15.4 nmol/hr/10(6) cells), and two had normal activity (34.7 and 58.2 nmol/hr/10(6) cells). B cells from all six patients with low ecto-5'-NT activity failed to synthesize Ig when cultured with PWM and normal irradiated T cells. Of the two patients with normal B cell ecto-5'-NT activity, one also had B cells unresponsive to PWM, but B cells from the other patient appeared to more normal, in that they synthesized IgM and IgG when cultured with PWM plus irradiated allogeneic T cells. Thus, measurement of B cell ecto-5'-NT activity allows the subclassification of patients who have a common inability to synthesize immunoglobulin in vitro response to PWM. B cells with low ecto-5'-NT activity are presumably blocked at an earlier stage in development than B cells with normal ecto-5'-NT activity. Evaluation of ecto-5'-NT activity along with the expression of other B cell surface antigens should aid in the definition of discrete stages of B cell development.
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Thompson LF, Ruedi JM, O'Connor RD, Bastian JF. Ecto-5'-nucleotidase expression during human B cell development. An explanation for the heterogeneity in B lymphocyte ecto-5'-nucleotidase activity in patients with hypogammaglobulinemia. J Immunol 1986; 137:2496-500. [PMID: 3020125] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Ecto-5'-nucleotidase (ecto-5'-NT) activity was measured in human B cells at different stages of development. Ecto-5'-NT activity of B cell preparations from fetal spleen and cord blood was 5.08 and 5.59 +/- 2.8 nmol/hr/10(6) cells, respectively; that of B cell preparations from adult peripheral blood, spleen, or lymph node was fivefold to sixfold higher (27.9 +/- 12, 29.2 and 33.8 nmol/hr/10(6) cells, respectively). The increased enzyme activity in B cell preparations from adult peripheral blood as compared with cord blood paralleled increased percentages of 5'-NT+ cells (69 +/- 12% vs 32 +/- 17%) and an average of twice as much enzyme activity per positive cell. Small, resting B cells that cannot synthesize Ig in vitro in response to pokeweed mitogen (PWM) were isolated from adult peripheral blood by mouse erythrocyte rosetting. Total ecto-5'-NT activity and the percentage of 5'-NT+ cells were equivalent in total B cells and the mouse erythrocyte rosette-positive subpopulation. Thus, ecto-5'-NT activity is acquired before B cells gain the ability to differentiate into Ig-secreting plasma cells in response to PWM. Ecto-5'-NT activity was also measured in B cell preparations from eight patients with common variable immunodeficiency. Six had reduced ecto-5'-NT activity (2.83 to 15.4 nmol/hr/10(6) cells), and two had normal activity (34.7 and 58.2 nmol/hr/10(6) cells). B cells from all six patients with low ecto-5'-NT activity failed to synthesize Ig when cultured with PWM and normal irradiated T cells. Of the two patients with normal B cell ecto-5'-NT activity, one also had B cells unresponsive to PWM, but B cells from the other patient appeared to more normal, in that they synthesized IgM and IgG when cultured with PWM plus irradiated allogeneic T cells. Thus, measurement of B cell ecto-5'-NT activity allows the subclassification of patients who have a common inability to synthesize immunoglobulin in vitro response to PWM. B cells with low ecto-5'-NT activity are presumably blocked at an earlier stage in development than B cells with normal ecto-5'-NT activity. Evaluation of ecto-5'-NT activity along with the expression of other B cell surface antigens should aid in the definition of discrete stages of B cell development.
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Thompson LF, Ruedi JM, O'Connor RD, Bastian JF. An explanation for the heterogeneity in B lymphocyte ecto-5'-nucleotidase activity in patients with hypogammaglobulinemia. Adv Exp Med Biol 1986; 195 Pt B:399-405. [PMID: 3020914 DOI: 10.1007/978-1-4684-1248-2_63] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
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