1
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Ghiboub M, Koster J, Craggs PD, Li Yim AYF, Shillings A, Hutchinson S, Bingham RP, Gatfield K, Hageman IL, Yao G, O’Keefe HP, Coffin A, Patel A, Sloan LA, Mitchell DJ, Hayhow TG, Lunven L, Watson RJ, Blunt CE, Harrison LA, Bruton G, Kumar U, Hamer N, Spaull JR, Zwijnenburg DA, Welting O, Hakvoort TBM, te Velde AA, van Limbergen J, Henneman P, Prinjha RK, de Winther MPJ, Harker NR, Tough DF, de Jonge WJ. Modulation of macrophage inflammatory function through selective inhibition of the epigenetic reader protein SP140. BMC Biol 2022; 20:182. [PMID: 35986286 PMCID: PMC9392322 DOI: 10.1186/s12915-022-01380-6] [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] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2021] [Accepted: 07/28/2022] [Indexed: 11/10/2022] Open
Abstract
Background SP140 is a bromodomain-containing protein expressed predominantly in immune cells. Genetic polymorphisms and epigenetic modifications in the SP140 locus have been linked to Crohn’s disease (CD), suggesting a role in inflammation. Results We report the development of the first small molecule SP140 inhibitor (GSK761) and utilize this to elucidate SP140 function in macrophages. We show that SP140 is highly expressed in CD mucosal macrophages and in in vitro-generated inflammatory macrophages. SP140 inhibition through GSK761 reduced monocyte-to-inflammatory macrophage differentiation and lipopolysaccharide (LPS)-induced inflammatory activation, while inducing the generation of CD206+ regulatory macrophages that were shown to associate with a therapeutic response to anti-TNF in CD patients. SP140 preferentially occupies transcriptional start sites in inflammatory macrophages, with enrichment at gene loci encoding pro-inflammatory cytokines/chemokines and inflammatory pathways. GSK761 specifically reduces SP140 chromatin binding and thereby expression of SP140-regulated genes. GSK761 inhibits the expression of cytokines, including TNF, by CD14+ macrophages isolated from CD intestinal mucosa. Conclusions This study identifies SP140 as a druggable epigenetic therapeutic target for CD. Supplementary Information The online version contains supplementary material available at 10.1186/s12915-022-01380-6.
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2
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Humphreys PG, Atkinson SJ, Bamborough P, Bit RA, Chung CW, Craggs PD, Cutler L, Davis R, Ferrie A, Gong G, Gordon LJ, Gray M, Harrison LA, Hayhow TG, Haynes A, Henley N, Hirst DJ, Holyer ID, Lindon MJ, Lovatt C, Lugo D, McCleary S, Molnar J, Osmani Q, Patten C, Preston A, Rioja I, Seal JT, Smithers N, Sun F, Tang D, Taylor S, Theodoulou NH, Thomas C, Watson RJ, Wellaway CR, Zhu L, Tomkinson NCO, Prinjha RK. Design, Synthesis, and Characterization of I-BET567, a Pan-Bromodomain and Extra Terminal (BET) Bromodomain Oral Candidate. J Med Chem 2022; 65:2262-2287. [PMID: 34995458 DOI: 10.1021/acs.jmedchem.1c01747] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Through regulation of the epigenome, the bromodomain and extra terminal (BET) family of proteins represent important therapeutic targets for the treatment of human disease. Through mimicking the endogenous N-acetyl-lysine group and disrupting the protein-protein interaction between histone tails and the bromodomain, several small molecule pan-BET inhibitors have progressed to oncology clinical trials. This work describes the medicinal chemistry strategy and execution to deliver an orally bioavailable tetrahydroquinoline (THQ) pan-BET candidate. Critical to the success of this endeavor was a potency agnostic analysis of a data set of 1999 THQ BET inhibitors within the GSK collection which enabled identification of appropriate lipophilicity space to deliver compounds with a higher probability of desired oral candidate quality properties. SAR knowledge was leveraged via Free-Wilson analysis within this design space to identify a small group of targets which ultimately delivered I-BET567 (27), a pan-BET candidate inhibitor that demonstrated efficacy in mouse models of oncology and inflammation.
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Affiliation(s)
| | | | - Paul Bamborough
- GlaxoSmithKline R&D, Stevenage, Hertfordshire SG1 2NY, United Kingdom
| | - Rino A Bit
- GlaxoSmithKline R&D, Stevenage, Hertfordshire SG1 2NY, United Kingdom
| | - Chun-Wa Chung
- GlaxoSmithKline R&D, Stevenage, Hertfordshire SG1 2NY, United Kingdom
| | - Peter D Craggs
- GlaxoSmithKline R&D, Stevenage, Hertfordshire SG1 2NY, United Kingdom
| | - Leanne Cutler
- GlaxoSmithKline R&D, Stevenage, Hertfordshire SG1 2NY, United Kingdom
| | - Rob Davis
- GlaxoSmithKline R&D, Stevenage, Hertfordshire SG1 2NY, United Kingdom
| | - Alan Ferrie
- GlaxoSmithKline R&D, Stevenage, Hertfordshire SG1 2NY, United Kingdom
| | - GangLi Gong
- WuXi Shanghai STA Pharmaceutical R&D Co., Ltd., No. 90 Delin Road, WaiGaoQiao Free Trade Zone, Shanghai 200131, China
| | - Laurie J Gordon
- GlaxoSmithKline R&D, Stevenage, Hertfordshire SG1 2NY, United Kingdom
| | - Matthew Gray
- GlaxoSmithKline R&D, Stevenage, Hertfordshire SG1 2NY, United Kingdom
| | - Lee A Harrison
- GlaxoSmithKline R&D, Stevenage, Hertfordshire SG1 2NY, United Kingdom
| | - Thomas G Hayhow
- GlaxoSmithKline R&D, Stevenage, Hertfordshire SG1 2NY, United Kingdom
| | - Andrea Haynes
- GlaxoSmithKline R&D, Stevenage, Hertfordshire SG1 2NY, United Kingdom
| | - Nick Henley
- GlaxoSmithKline R&D, Stevenage, Hertfordshire SG1 2NY, United Kingdom
| | - David J Hirst
- GlaxoSmithKline R&D, Stevenage, Hertfordshire SG1 2NY, United Kingdom
| | - Ian D Holyer
- GlaxoSmithKline R&D, Stevenage, Hertfordshire SG1 2NY, United Kingdom
| | - Matthew J Lindon
- GlaxoSmithKline R&D, Stevenage, Hertfordshire SG1 2NY, United Kingdom
| | - Cerys Lovatt
- GlaxoSmithKline R&D, Stevenage, Hertfordshire SG1 2NY, United Kingdom
| | - David Lugo
- GlaxoSmithKline R&D, Stevenage, Hertfordshire SG1 2NY, United Kingdom
| | - Scott McCleary
- GlaxoSmithKline R&D, Stevenage, Hertfordshire SG1 2NY, United Kingdom
| | - Judit Molnar
- GlaxoSmithKline R&D, Stevenage, Hertfordshire SG1 2NY, United Kingdom
| | - Qendresa Osmani
- GlaxoSmithKline R&D, Stevenage, Hertfordshire SG1 2NY, United Kingdom
| | - Chris Patten
- GlaxoSmithKline R&D, Stevenage, Hertfordshire SG1 2NY, United Kingdom
| | - Alex Preston
- GlaxoSmithKline R&D, Stevenage, Hertfordshire SG1 2NY, United Kingdom
| | - Inmaculada Rioja
- GlaxoSmithKline R&D, Stevenage, Hertfordshire SG1 2NY, United Kingdom
| | - Jonathan T Seal
- GlaxoSmithKline R&D, Stevenage, Hertfordshire SG1 2NY, United Kingdom
| | - Nicholas Smithers
- GlaxoSmithKline R&D, Stevenage, Hertfordshire SG1 2NY, United Kingdom
| | - Fenglai Sun
- WuXi Shanghai STA Pharmaceutical R&D Co., Ltd., No. 90 Delin Road, WaiGaoQiao Free Trade Zone, Shanghai 200131, China
| | - Dalin Tang
- WuXi Shanghai STA Pharmaceutical R&D Co., Ltd., No. 90 Delin Road, WaiGaoQiao Free Trade Zone, Shanghai 200131, China
| | - Simon Taylor
- GlaxoSmithKline R&D, Stevenage, Hertfordshire SG1 2NY, United Kingdom
| | - Natalie H Theodoulou
- GlaxoSmithKline R&D, Stevenage, Hertfordshire SG1 2NY, United Kingdom.,WestCHEM, Department of Pure and Applied Chemistry, University of Strathclyde, Thomas Graham Building, 295 Cathedral Street, Glasgow G1 1XL, United Kingdom
| | - Clare Thomas
- GlaxoSmithKline R&D, Stevenage, Hertfordshire SG1 2NY, United Kingdom
| | - Robert J Watson
- GlaxoSmithKline R&D, Stevenage, Hertfordshire SG1 2NY, United Kingdom
| | | | - Linrong Zhu
- WuXi Shanghai STA Pharmaceutical R&D Co., Ltd., No. 90 Delin Road, WaiGaoQiao Free Trade Zone, Shanghai 200131, China
| | - Nicholas C O Tomkinson
- WestCHEM, Department of Pure and Applied Chemistry, University of Strathclyde, Thomas Graham Building, 295 Cathedral Street, Glasgow G1 1XL, United Kingdom
| | - Rab K Prinjha
- GlaxoSmithKline R&D, Stevenage, Hertfordshire SG1 2NY, United Kingdom
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3
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Seal JT, Atkinson SJ, Bamborough P, Bassil A, Chung CW, Foley J, Gordon L, Grandi P, Gray JRJ, Harrison LA, Kruger RG, Matteo JJ, McCabe MT, Messenger C, Mitchell D, Phillipou A, Preston A, Prinjha RK, Rianjongdee F, Rioja I, Taylor S, Wall ID, Watson RJ, Woolven JM, Wyce A, Zhang XP, Demont EH. Fragment-based Scaffold Hopping: Identification of Potent, Selective, and Highly Soluble Bromo and Extra Terminal Domain (BET) Second Bromodomain (BD2) Inhibitors. J Med Chem 2021; 64:10772-10805. [PMID: 34255512 DOI: 10.1021/acs.jmedchem.1c00365] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
The profound efficacy of pan-BET inhibitors is well documented, but these epigenetic agents have shown pharmacology-driven toxicity in oncology clinical trials. The opportunity to identify inhibitors with an improved safety profile by selective targeting of a subset of the eight bromodomains of the BET family has triggered extensive medicinal chemistry efforts. In this article, we disclose the identification of potent and selective drug-like pan-BD2 inhibitors such as pyrazole 23 (GSK809) and furan 24 (GSK743) that were derived from the pyrrole fragment 6. We transpose the key learnings from a previous pyridone series (GSK620 2 as a representative example) to this novel class of inhibitors, which are characterized by significantly improved solubility relative to our previous research.
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Affiliation(s)
| | | | | | | | | | - James Foley
- Cancer Epigenetics Research Unit, GlaxoSmithKline, 1250 South Collegeville Road, Collegeville, Pennsylvania 19426, United States
| | | | - Paola Grandi
- IVIVT Cellzome, Platform Technology and Science, GlaxoSmithKline, Meyerhofstr. 1, 69117 Heidelberg, Germany
| | | | | | - Ryan G Kruger
- Cancer Epigenetics Research Unit, GlaxoSmithKline, 1250 South Collegeville Road, Collegeville, Pennsylvania 19426, United States
| | - Jeanne J Matteo
- Cancer Epigenetics Research Unit, GlaxoSmithKline, 1250 South Collegeville Road, Collegeville, Pennsylvania 19426, United States
| | - Michael T McCabe
- Cancer Epigenetics Research Unit, GlaxoSmithKline, 1250 South Collegeville Road, Collegeville, Pennsylvania 19426, United States
| | | | | | | | | | | | | | | | | | | | | | | | - Anastasia Wyce
- Cancer Epigenetics Research Unit, GlaxoSmithKline, 1250 South Collegeville Road, Collegeville, Pennsylvania 19426, United States
| | - Xi-Ping Zhang
- Cancer Epigenetics Research Unit, GlaxoSmithKline, 1250 South Collegeville Road, Collegeville, Pennsylvania 19426, United States
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4
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Harrison LA, Atkinson SJ, Bassil A, Chung CW, Grandi P, Gray JRJ, Levernier E, Lewis A, Lugo D, Messenger C, Michon AM, Mitchell DJ, Preston A, Prinjha RK, Rioja I, Seal JT, Taylor S, Wall ID, Watson RJ, Woolven JM, Demont EH. Identification of a Series of N-Methylpyridine-2-carboxamides as Potent and Selective Inhibitors of the Second Bromodomain (BD2) of the Bromo and Extra Terminal Domain (BET) Proteins. J Med Chem 2021; 64:10742-10771. [PMID: 34232650 DOI: 10.1021/acs.jmedchem.0c02155] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Domain-specific BET bromodomain ligands represent an attractive target for drug discovery with the potential to unlock the therapeutic benefits of antagonizing these proteins without eliciting the toxicological aspects seen with pan-BET inhibitors. While we have reported several distinct classes of BD2 selective compounds, namely, GSK620, GSK549, and GSK046, only GSK046 shows high aqueous solubility. Herein, we describe the lead optimization of a further class of highly soluble compounds based upon a picolinamide chemotype. Focusing on achieving >1000-fold selectivity for BD2 over BD1 ,while retaining favorable physical chemical properties, compound 36 was identified as being 2000-fold selective for BD2 over BD1 (Brd4 data) with >1 mg/mL solubility in FaSSIF media. 36 represents a valuable new in vivo ready molecule for the exploration of the BD2 phenotype.
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Affiliation(s)
- Lee A Harrison
- Epigenetics Discovery Performance Unit, GlaxoSmithKline, Medicines Research Centre, Stevenage, Hertfordshire SG1 2NY, U.K
| | - Stephen J Atkinson
- Epigenetics Discovery Performance Unit, GlaxoSmithKline, Medicines Research Centre, Stevenage, Hertfordshire SG1 2NY, U.K
| | - Anna Bassil
- Epigenetics Discovery Performance Unit, GlaxoSmithKline, Medicines Research Centre, Stevenage, Hertfordshire SG1 2NY, U.K
| | - Chun-Wa Chung
- Platform Technology and Science, GlaxoSmithKline, Medicines Research Centre, Stevenage, Hertfordshire SG1 2NY, U.K
| | - Paola Grandi
- IVIVT Cellzome, Platform Technology and Science, GlaxoSmithKline, Meyerhofstr. 1, 69117 Heidelberg, Germany
| | - James R J Gray
- Quantitative Pharmacology, Immunoinflammation Therapy Area Unit, GlaxoSmithKline, Medicines Research Centre, Stevenage, Hertfordshire SG1 2NY, U.K
| | - Etienne Levernier
- Epigenetics Discovery Performance Unit, GlaxoSmithKline, Medicines Research Centre, Stevenage, Hertfordshire SG1 2NY, U.K
| | - Antonia Lewis
- Platform Technology and Science, GlaxoSmithKline, Medicines Research Centre, Stevenage, Hertfordshire SG1 2NY, U.K
| | - David Lugo
- Quantitative Pharmacology, Immunoinflammation Therapy Area Unit, GlaxoSmithKline, Medicines Research Centre, Stevenage, Hertfordshire SG1 2NY, U.K
| | - Cassie Messenger
- Platform Technology and Science, GlaxoSmithKline, Medicines Research Centre, Stevenage, Hertfordshire SG1 2NY, U.K
| | - Anne-Marie Michon
- IVIVT Cellzome, Platform Technology and Science, GlaxoSmithKline, Meyerhofstr. 1, 69117 Heidelberg, Germany
| | - Darren J Mitchell
- Epigenetics Discovery Performance Unit, GlaxoSmithKline, Medicines Research Centre, Stevenage, Hertfordshire SG1 2NY, U.K
| | - Alex Preston
- Epigenetics Discovery Performance Unit, GlaxoSmithKline, Medicines Research Centre, Stevenage, Hertfordshire SG1 2NY, U.K
| | - Rab K Prinjha
- Epigenetics Discovery Performance Unit, GlaxoSmithKline, Medicines Research Centre, Stevenage, Hertfordshire SG1 2NY, U.K
| | - Inmaculada Rioja
- Epigenetics Discovery Performance Unit, GlaxoSmithKline, Medicines Research Centre, Stevenage, Hertfordshire SG1 2NY, U.K
| | - Jonathan T Seal
- Epigenetics Discovery Performance Unit, GlaxoSmithKline, Medicines Research Centre, Stevenage, Hertfordshire SG1 2NY, U.K
| | - Simon Taylor
- Quantitative Pharmacology, Immunoinflammation Therapy Area Unit, GlaxoSmithKline, Medicines Research Centre, Stevenage, Hertfordshire SG1 2NY, U.K
| | - Ian D Wall
- Platform Technology and Science, GlaxoSmithKline, Medicines Research Centre, Stevenage, Hertfordshire SG1 2NY, U.K
| | - Robert J Watson
- Epigenetics Discovery Performance Unit, GlaxoSmithKline, Medicines Research Centre, Stevenage, Hertfordshire SG1 2NY, U.K
| | - James M Woolven
- Platform Technology and Science, GlaxoSmithKline, Medicines Research Centre, Stevenage, Hertfordshire SG1 2NY, U.K
| | - Emmanuel H Demont
- Epigenetics Discovery Performance Unit, GlaxoSmithKline, Medicines Research Centre, Stevenage, Hertfordshire SG1 2NY, U.K
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5
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Aylott HE, Atkinson SJ, Bamborough P, Bassil A, Chung CW, Gordon L, Grandi P, Gray JRJ, Harrison LA, Hayhow TG, Messenger C, Mitchell D, Phillipou A, Preston A, Prinjha RK, Rianjongdee F, Rioja I, Seal JT, Wall ID, Watson RJ, Woolven JM, Demont EH. Template-Hopping Approach Leads to Potent, Selective, and Highly Soluble Bromo and Extraterminal Domain (BET) Second Bromodomain (BD2) Inhibitors. J Med Chem 2021; 64:3249-3281. [PMID: 33662213 DOI: 10.1021/acs.jmedchem.0c02156] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
A number of reports have recently been published describing the discovery and optimization of bromo and extraterminal inhibitors which are selective for the second bromodomain (BD2); these include our own work toward GSK046 (3) and GSK620 (5). This paper describes our approach to mitigating the genotoxicity risk of GSK046 by replacement of the acetamide functionality with a heterocyclic ring. This was followed by a template-hopping and hybridization approach, guided by structure-based drug design, to incorporate learnings from other BD2-selective series, optimize the vector for the amide region, and explore the ZA cleft, leading to the identification of potent, selective, and bioavailable compounds 28 (GSK452), 39 (GSK737), and 36 (GSK217).
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Affiliation(s)
- Helen E Aylott
- Epigenetics Discovery Performance Unit, GlaxoSmithKline, Medicines Research Centre, Stevenage, Hertfordshire SG1 2NY, U.K
| | - Stephen J Atkinson
- Epigenetics Discovery Performance Unit, GlaxoSmithKline, Medicines Research Centre, Stevenage, Hertfordshire SG1 2NY, U.K
| | - Paul Bamborough
- Platform Technology and Science, GlaxoSmithKline, Medicines Research Centre, Stevenage, Hertfordshire SG1 2NY, U.K
| | - Anna Bassil
- Epigenetics Discovery Performance Unit, GlaxoSmithKline, Medicines Research Centre, Stevenage, Hertfordshire SG1 2NY, U.K
| | - Chun-Wa Chung
- Platform Technology and Science, GlaxoSmithKline, Medicines Research Centre, Stevenage, Hertfordshire SG1 2NY, U.K
| | - Laurie Gordon
- Platform Technology and Science, GlaxoSmithKline, Medicines Research Centre, Stevenage, Hertfordshire SG1 2NY, U.K
| | - Paola Grandi
- IVIVT Cellzome, Platform Technology and Science, GlaxoSmithKline, Meyerhofstr. 1, Heidelberg 69117, Germany
| | - James R J Gray
- Quantitative Pharmacology, Immunoinflammation Therapy Area Unit, GlaxoSmithKline, Medicines Research Centre, Stevenage, Hertfordshire SG1 2NY, U.K
| | - Lee A Harrison
- Epigenetics Discovery Performance Unit, GlaxoSmithKline, Medicines Research Centre, Stevenage, Hertfordshire SG1 2NY, U.K
| | - Thomas G Hayhow
- Epigenetics Discovery Performance Unit, GlaxoSmithKline, Medicines Research Centre, Stevenage, Hertfordshire SG1 2NY, U.K
| | - Cassie Messenger
- Platform Technology and Science, GlaxoSmithKline, Medicines Research Centre, Stevenage, Hertfordshire SG1 2NY, U.K
| | - Darren Mitchell
- Epigenetics Discovery Performance Unit, GlaxoSmithKline, Medicines Research Centre, Stevenage, Hertfordshire SG1 2NY, U.K
| | - Alexander Phillipou
- Platform Technology and Science, GlaxoSmithKline, Medicines Research Centre, Stevenage, Hertfordshire SG1 2NY, U.K
| | - Alex Preston
- Epigenetics Discovery Performance Unit, GlaxoSmithKline, Medicines Research Centre, Stevenage, Hertfordshire SG1 2NY, U.K
| | - Rab K Prinjha
- Epigenetics Discovery Performance Unit, GlaxoSmithKline, Medicines Research Centre, Stevenage, Hertfordshire SG1 2NY, U.K
| | - Francesco Rianjongdee
- Epigenetics Discovery Performance Unit, GlaxoSmithKline, Medicines Research Centre, Stevenage, Hertfordshire SG1 2NY, U.K
| | - Inmaculada Rioja
- Epigenetics Discovery Performance Unit, GlaxoSmithKline, Medicines Research Centre, Stevenage, Hertfordshire SG1 2NY, U.K
| | - Jonathan T Seal
- Epigenetics Discovery Performance Unit, GlaxoSmithKline, Medicines Research Centre, Stevenage, Hertfordshire SG1 2NY, U.K
| | - Ian D Wall
- Platform Technology and Science, GlaxoSmithKline, Medicines Research Centre, Stevenage, Hertfordshire SG1 2NY, U.K
| | - Robert J Watson
- Epigenetics Discovery Performance Unit, GlaxoSmithKline, Medicines Research Centre, Stevenage, Hertfordshire SG1 2NY, U.K
| | - James M Woolven
- Platform Technology and Science, GlaxoSmithKline, Medicines Research Centre, Stevenage, Hertfordshire SG1 2NY, U.K
| | - Emmanuel H Demont
- Epigenetics Discovery Performance Unit, GlaxoSmithKline, Medicines Research Centre, Stevenage, Hertfordshire SG1 2NY, U.K
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6
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Preston A, Atkinson SJ, Bamborough P, Chung CW, Gordon LJ, Grandi P, Gray JRJ, Harrison LA, Lewis AJ, Lugo D, Messenger C, Michon AM, Mitchell DJ, Prinjha RK, Rioja I, Seal J, Taylor S, Thesmar P, Wall ID, Watson RJ, Woolven JM, Demont EH. GSK973 Is an Inhibitor of the Second Bromodomains (BD2s) of the Bromodomain and Extra-Terminal (BET) Family. ACS Med Chem Lett 2020; 11:1581-1587. [PMID: 32832027 DOI: 10.1021/acsmedchemlett.0c00247] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2020] [Accepted: 07/06/2020] [Indexed: 12/17/2022] Open
Abstract
Pan-BET inhibitors have shown profound efficacy in a number of in vivo preclinical models and have entered the clinic in oncology trials where adverse events have been reported. These inhibitors interact equipotently with the eight bromodomains of the BET family of proteins. To better understand the contribution of each domain to their efficacy and to improve from their safety profile, selective inhibitors are required. This Letter discloses the profile of GSK973, a highly selective inhibitor of the second bromodomains of the BET proteins that has undergone extensive preclinical in vitro and in vivo characterization.
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Affiliation(s)
| | | | | | | | | | - Paola Grandi
- Cellzome GmbH, GlaxoSmithKline, Meyerhofstrasse 1, 69117 Heidelberg, Germany
| | | | | | | | | | | | - Anne-Marie Michon
- Cellzome GmbH, GlaxoSmithKline, Meyerhofstrasse 1, 69117 Heidelberg, Germany
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7
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Seal JT, Atkinson SJ, Aylott H, Bamborough P, Chung CW, Copley RCB, Gordon L, Grandi P, Gray JRJ, Harrison LA, Hayhow TG, Lindon M, Messenger C, Michon AM, Mitchell D, Preston A, Prinjha RK, Rioja I, Taylor S, Wall ID, Watson RJ, Woolven JM, Demont EH. The Optimization of a Novel, Weak Bromo and Extra Terminal Domain (BET) Bromodomain Fragment Ligand to a Potent and Selective Second Bromodomain (BD2) Inhibitor. J Med Chem 2020; 63:9093-9126. [DOI: 10.1021/acs.jmedchem.0c00796] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Affiliation(s)
| | | | | | | | | | | | | | - Paola Grandi
- IVIVT Cellzome, Platform Technology and Science, GlaxoSmithKline, Meyerhofstrasse 1, 69117 Heidelberg, Germany
| | | | | | | | | | | | - Anne-Marie Michon
- IVIVT Cellzome, Platform Technology and Science, GlaxoSmithKline, Meyerhofstrasse 1, 69117 Heidelberg, Germany
| | | | | | | | | | - Simon Taylor
- IVIVT Cellzome, Platform Technology and Science, GlaxoSmithKline, Meyerhofstrasse 1, 69117 Heidelberg, Germany
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8
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Okubara PA, Harrison LA, Gatch EW, Vandemark G, Schroeder KL, du Toit LJ. Development and Evaluation of a TaqMan Real-Time PCR Assay for Fusarium oxysporum f. sp. spinaciae. Plant Dis 2013; 97:927-937. [PMID: 30722577 DOI: 10.1094/pdis-03-12-0317-re] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Fusarium oxysporum f. sp. spinaciae, causal agent of spinach Fusarium wilt, is an important soilborne pathogen in many areas of the world where spinach is grown. The pathogen is persistent in acid soils of maritime western Oregon and Washington, the only region of the United States suitable for commercial spinach seed production. A TaqMan real-time polymerase chain reaction (PCR) assay was developed for rapid identification and quantification of the pathogen, based on sequencing the intergenic spacer (IGS) region of rDNA of isolates of the pathogen. A guanine single-nucleotide polymorphism (G SNP) was detected in the IGS sequences of 36 geographically diverse isolates of F. oxysporum f. sp. spinaciae but not in the sequences of 64 isolates representing other formae speciales and 33 isolates representing other fungal species or genera. The SNP was used to develop a probe for a real-time PCR assay. The real-time PCR assay detected F. oxysporum f. sp. spinaciae at 3-14,056 CFU/g of soil in 82 soil samples collected over 3 years from naturally infested spinach seed production sites in western Washington, although a reliable detection limit of the assay was determined to be 11 CFU/g of soil. A significant (P < 0.05), positive correlation between enumeration of F. oxysporum on Komada's agar and quantification of the pathogen using the TaqMan assay was observed in a comparison of 82 soil samples. Correlations between pathogen DNA levels, Fusarium wilt severity ratings, and spinach biomass were significantly positive for one set of naturally infested soils but not between pathogen DNA levels, wilt incidence ratings, and spinach biomass for other soil samples, suggesting that soilborne pathogen population is not the sole determinant of spinach Fusarium wilt incidence or severity. The presence of the G SNP detected in one isolate of each of F. oxysporum ff. spp. lageneriae, lilii, melongenae, and raphani and reaction of the real-time PCR assay with 16 of 22 nonpathogenic isolates of F. oxysporum associated with spinach plants or soil in which spinach had been grown potentially limits the application of this assay. Nonetheless, because all isolates of F. oxysporum f. sp. spinaciae tested positive with the real-time PCR assay, the assay may provide a valuable means of screening for resistance to Fusarium wilt by quantifying development of the pathogen in spinach plants inoculated with the pathogen.
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Affiliation(s)
- P A Okubara
- United States Department of Agriculture-Agricultural Research Service (USDA-ARS), Root Disease and Biological Control Research Unit, Pullman, WA 99164
| | | | - E W Gatch
- graduate student, Washington State University Mount Vernon NWREC, Mount Vernon 98273
| | - G Vandemark
- USDA-ARS, Grain Legume Genetics and Physiology Research Unit, Pullman, WA 99164
| | - K L Schroeder
- Department of Plant Pathology, Washington State University, Pullman 99164
| | - L J du Toit
- Washington State University Mount Vernon NWREC
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9
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Demont EH, Arpino S, Bit RA, Campbell CA, Deeks N, Desai S, Dowell SJ, Gaskin P, Gray JRJ, Harrison LA, Haynes A, Heightman TD, Holmes DS, Humphreys PG, Kumar U, Morse MA, Osborne GJ, Panchal T, Philpott KL, Taylor S, Watson R, Willis R, Witherington J. Discovery of a brain-penetrant S1P₃-sparing direct agonist of the S1P₁ and S1P₅ receptors efficacious at low oral dose. J Med Chem 2011; 54:6724-33. [PMID: 21838322 DOI: 10.1021/jm200609t] [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] [Indexed: 02/02/2023]
Abstract
2-Amino-2-(4-octylphenethyl)propane-1,3-diol 1 (fingolimod, FTY720) has been recently marketed in the United States for the treatment of patients with remitting relapsing multiple sclerosis (RRMS). Its efficacy has been primarily linked to the agonism on T cells of S1P(1), one of the five sphingosine 1-phosphate (S1P) G-protein-coupled receptors, while its cardiovascular side effects have been associated with activity at S1P(3). Emerging data suggest that the ability of this molecule to cross the blood-brain barrier and to interact with both S1P(1) and S1P(5) in the central nervous system (CNS) may contribute to its efficacy in treating patients with RRMS. We have recently disclosed the structure of an advanced, first generation S1P(3)-sparing S1P(1) agonist, a zwitterion with limited CNS exposure. In this Article, we highlight our strategy toward the identification of CNS-penetrant S1P(3)-sparing S1P(1) and S1P(5) agonists resulting in the discovery of 5-(3-{2-[2-hydroxy-1-(hydroxymethyl)ethyl]-5-methyl-1,2,3,4-tetrahydro-6-isoquinolinyl}-1,2,4-oxadiazol-5-yl)-2-[(1-methylethyl)oxy]benzonitrile 15. Its exceptional in vivo potency and good pharmacokinetic properties translate into a very low predicted therapeutic dose in human (<1 mg p.o. once daily).
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Affiliation(s)
- Emmanuel H Demont
- Immuno Inflammation Center of Excellence for Drug Discovery, GlaxoSmithKline, Gunnels Wood Road, Stevenage SG1 2NY, United Kingdom.
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10
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Lam BS, Strobel GA, Harrison LA, Lam ST. Transposon mutagenesis and tagging of fluorescent Pseudomonas: Antimycotic production is necessary for control of Dutch elm disease. Proc Natl Acad Sci U S A 2010; 84:6447-51. [PMID: 16593875 PMCID: PMC299094 DOI: 10.1073/pnas.84.18.6447] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Antimycotic-producing strains of Pseudomonas syringae are being tested as Dutch elm disease control agents. We examined the role of antimycotic production in disease control. Transposon Tn903 was used to mutagenize the antimycotic-producing strain MSU174. Eighty-one mutants that did not inhibit fungal growth were identified among 15,000 Tn903-containing derivatives. Linkages between Tn903 insertions and defects in antimycotic metabolism were established. Three Tn903-containing strains (two antimycotic producers and one nonproducer) were individually introduced into American elm seedlings. The seedlings were subsequently challenged with Ceratocystis ulmi, the causal agent of Dutch elm disease. Protection of the elms was observed with the two antimycotic-producing strains but not with the nonproducing strain. The introduced strains could be readily recovered from the seedlings after two growing seasons. They were unequivocally identified by the Tn903 insertions they contain.
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Affiliation(s)
- B S Lam
- Department of Plant Pathology, Montana State University, Bozeman, MT 59717
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11
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Macdonald SJF, Dowle MD, Harrison LA, Clarke GDE, Inglis GGA, Johnson MR, Shah P, Smith RA, Amour A, Fleetwood G, Humphreys DC, Molloy CR, Dixon M, Godward RE, Wonacott AJ, Singh OMP, Hodgson ST, Hardy GW. Discovery of further pyrrolidine trans-lactams as inhibitors of human neutrophil elastase (HNE) with potential as development candidates and the crystal structure of HNE complexed with an inhibitor (GW475151). J Med Chem 2002; 45:3878-90. [PMID: 12190311 DOI: 10.1021/jm020881f] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.1] [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: 11/30/2022]
Abstract
Described herein is a modern approach to the rapid preparation and evaluation of compounds as potential back-up drug candidates. GW311616A, 1, a derivative of pyrrolidine trans-lactams, has previously been described as a potent, orally active inhibitor of human neutrophil elastase (HNE) for the treatment of respiratory disease. These properties made it a suitable candidate for development. Described here is the discovery of three further derivatives of pyrrolidine trans-lactams, which fulfill the criteria required for back-up candidates 28, 29, and 32. These include increased activity in inhibiting HNE in human whole blood (HWB) and comparable pharmacokinetic properties, in particular clearance, in two species. To provide a rapid assessment of clearance, cassette dosing in dog was used. Modern array techniques, including the synthesis of mixtures, were used to synthesize compounds rapidly. Having selected three potential compounds as back-up candidates, they were prepared as single enantiomers and profiled in in vitro and in vivo assays and evaluated pharmacokinetically in rat and dog. These compounds are highly potent and selective HNE inhibitors, with a prolonged pharmacodynamic action. Pharmacokinetically, these compounds are comparable with 1 while they are more potent in HWB. Compound 28, however, has a higher clearance. One of these compounds, 32, was cocrystallized with HNE, and features of this structure are described and compared with the cocrystal structure of 1 in porcine pancreatic elastase.
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Affiliation(s)
- Simon J F Macdonald
- Medicinal Chemistry 1, In Vitro Pharmacology, Systems Research, Respiratory Systems, Stevenage CEDD DMPK, United Kingdom.
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12
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Macdonald SJ, Dowle MD, Harrison LA, Spooner JE, Shah P, Johnson MR, Inglis GG, Clarke GD, Belton DJ, Smith RA, Molloy CR, Dixon M, Murkitt G, Godward RE, Skarzynski T, Singh OM, Kumar K, Hodgson ST, McDonald E, Hardy GW, Finch H, Humphreys DC, Fleetwood G. Corrigendum to “Intracellular inhibition of human neutrophil elastase by orally active pyrrolidine-trans-lactams”. Bioorg Med Chem Lett 2001. [DOI: 10.1016/s0960-894x(01)00175-5] [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: 10/18/2022]
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13
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Macdonald SJ, Dowle MD, Harrison LA, Shah P, Johnson MR, Inglis GG, Clarke GD, Smith RA, Humphreys D, Molloy CR, Amour A, Dixon M, Murkitt G, Godward RE, Padfield T, Skarzynski T, Singh OM, Kumar KA, Fleetwood G, Hodgson ST, Hardy GW, Finch H. The discovery of a potent, intracellular, orally bioavailable, long duration inhibitor of human neutrophil elastase--GW311616A a development candidate. Bioorg Med Chem Lett 2001; 11:895-8. [PMID: 11294386 DOI: 10.1016/s0960-894x(01)00078-6] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.5] [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: 10/27/2022]
Abstract
The discovery of a potent intracellular inhibitor of human neutrophil elastase which is orally active and has a long duration of action is described. The pharmacodynamic and pharmacokinetic properties of a trans-lactam development candidate, GW311616A, are described.
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Affiliation(s)
- S J Macdonald
- Medicinal Chemistry 2, GlaxoWellcome Medicines Research Centre, Stevenage, UK.
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14
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Macdonald SJ, Dowle MD, Harrison LA, Spooner JE, Shah P, Johnson MR, Inglis GG, Clarke GD, Belton DJ, Smith RA, Molloy CR, Dixon M, Murkitt G, Godward RE, Skarzynski T, Singh OM, Kumar KA, Hodgson ST, McDonald E, Hardy GW, Finch H, Humphreys DC, Fleetwood G. Intracellular inhibition of human neutrophil elastase by orally active pyrrolidine-trans-lactams. Bioorg Med Chem Lett 2001; 11:243-6. [PMID: 11206469 DOI: 10.1016/s0960-894x(00)00632-6] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [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: 11/29/2022]
Abstract
Described are the acylation binding of trans-lactam 1 to porcine pancreatic elastase, the selection of the SO2Me activating group for the lactam N which also confers metabolic stability in hamster liver microsomes, the introduction of aqueous solubility through the piperidine salt 9, the in vivo oral activity of 9 and its bioavailability, and the introduction of 9 as an intracellular neutrophil elastase inhibitor.
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Affiliation(s)
- S J Macdonald
- Medical Chemistry 2, Glaxo Wellcome Medicines Research Centre, Stevenage, UK.
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15
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Macdonald SJF, Clarke GDE, Dowle MD, Harrison LA, Hodgson ST, Inglis GGA, Johnson MR, Shah P, Upton RJ, Walls SB. A Flexible, Practical, and Stereoselective Synthesis of Enantiomerically Pure trans-5-Oxohexahydropyrrolo[3,2-b]pyrroles (Pyrrolidine-trans-lactams), a New Class of Serine Protease Inhibitors, Using Acyliminium Methodology. J Org Chem 1999; 64:5166-5175. [DOI: 10.1021/jo990306s] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.2] [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)
- Simon J. F. Macdonald
- Enzyme Chemistry 2 and Physical Sciences, GlaxoWellcome Medicines Research Centre, Gunnels Wood Road, Stevenage SG1 2NY, U.K
| | - Geoffrey D. E. Clarke
- Enzyme Chemistry 2 and Physical Sciences, GlaxoWellcome Medicines Research Centre, Gunnels Wood Road, Stevenage SG1 2NY, U.K
| | - Michael D. Dowle
- Enzyme Chemistry 2 and Physical Sciences, GlaxoWellcome Medicines Research Centre, Gunnels Wood Road, Stevenage SG1 2NY, U.K
| | - Lee A. Harrison
- Enzyme Chemistry 2 and Physical Sciences, GlaxoWellcome Medicines Research Centre, Gunnels Wood Road, Stevenage SG1 2NY, U.K
| | - Simon T. Hodgson
- Enzyme Chemistry 2 and Physical Sciences, GlaxoWellcome Medicines Research Centre, Gunnels Wood Road, Stevenage SG1 2NY, U.K
| | - Graham G. A. Inglis
- Enzyme Chemistry 2 and Physical Sciences, GlaxoWellcome Medicines Research Centre, Gunnels Wood Road, Stevenage SG1 2NY, U.K
| | - Martin R. Johnson
- Enzyme Chemistry 2 and Physical Sciences, GlaxoWellcome Medicines Research Centre, Gunnels Wood Road, Stevenage SG1 2NY, U.K
| | - Prit Shah
- Enzyme Chemistry 2 and Physical Sciences, GlaxoWellcome Medicines Research Centre, Gunnels Wood Road, Stevenage SG1 2NY, U.K
| | - Richard J. Upton
- Enzyme Chemistry 2 and Physical Sciences, GlaxoWellcome Medicines Research Centre, Gunnels Wood Road, Stevenage SG1 2NY, U.K
| | - Steven B. Walls
- Enzyme Chemistry 2 and Physical Sciences, GlaxoWellcome Medicines Research Centre, Gunnels Wood Road, Stevenage SG1 2NY, U.K
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16
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Macdonald SJ, Belton DJ, Buckley DM, Spooner JE, Anson MS, Harrison LA, Mills K, Upton RJ, Dowle MD, Smith RA, Molloy CR, Risley C. Syntheses of trans-5-oxo-hexahydro-pyrrolo[3,2-b]pyrroles and trans-5-oxo-hexahydro-furo[3,2-b]pyrroles (pyrrolidine trans-lactams and trans-lactones): new pharmacophores for elastase inhibition. J Med Chem 1998; 41:3919-22. [PMID: 9767628 DOI: 10.1021/jm981026s] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- S J Macdonald
- Enzyme Chemistry 2, Development Chemistry 3, Physical Sciences, and Enzyme Pharmacology, GlaxoWellcome Medicines Research Centre, Gunnels Wood Road, Stevenage SG1 2NY, U.K
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17
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Schweiger GD, Redick ML, Siegel EL, Harrison LA, Rosenthal SJ. Hepatic arterial pseudoaneurysm after placement of transjugular intrahepatic portosystemic shunt. J Ultrasound Med 1997; 16:437-439. [PMID: 9315191 DOI: 10.7863/jum.1997.16.6.437] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Affiliation(s)
- G D Schweiger
- Department of Radiology, University of Iowa Hospitals and Clinics, Iowa City 52242, USA
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18
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Abstract
Confirming partial small bowel obstruction is often a diagnostic challenge. In this case report, 4-mm solid radiopaque markers were used in 4 patients to show partial small bowel obstruction. Results of enteroclysis were normal in 2 of the 4 patients, and the markers were used to challenge suspected partial obstruction. The markers coalesced in the region of the partial obstruction, which was confirmed at surgery. Enteroclysis is the examination of choice in the diagnosis of partial small bowel obstruction. However, examinations with false-negative results can occur, particularly with adhesive and/or intermittent obstructions. The use of radiopaque markers in these cases proved an effective and useful method of establishing the diagnosis of partial small bowel obstruction, particularly in the 2 cases in which enteroclysis results were normal. Prospective studies are needed to establish the feasibility of this novel technique.
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Affiliation(s)
- P A Johnson
- Department of Internal Medicine, University of Kansas Medical Center, Kansas City, USA
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19
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Harrison LA, Bailey MR, Naylor MW, Ream JE, Hammond BG, Nida DL, Burnette BL, Nickson TE, Mitsky TA, Taylor ML, Fuchs RL, Padgette SR. The expressed protein in glyphosate-tolerant soybean, 5-enolpyruvylshikimate-3-phosphate synthase from Agrobacterium sp. strain CP4, is rapidly digested in vitro and is not toxic to acutely gavaged mice. J Nutr 1996; 126:728-40. [PMID: 8598558 DOI: 10.1093/jn/126.3.728] [Citation(s) in RCA: 99] [Impact Index Per Article: 3.5] [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: 01/31/2023] Open
Abstract
The safety of 5-enolpyruvylshikimate-3-phosphate synthase enzyme derived from Agrobacterium sp. strain CP4 (CP4 EPSPS) was assessed. CP4 EPSPS is the only protein introduced by genetic manipulation that is expressed in glyphosate-tolerant soybeans, which are being developed to provide new weed-control options for farmers. Expression of this protein in plants imparts high levels of glyphosate tolerance. The safety of CP4 EPSPS was ascertained by evaluating both physical and functional characteristics. CP4 EPSPS degrades readily in simulated gastric and intestinal fluids, suggesting that this protein will be degraded in the mammalian digestive tract upon ingestion as a component of food or feed, There were no deleterious effects due to the acute administration of CP4 EPSPS to mice by gavage at a high dosage of 572 mg/kg body wt, which exceeds 1000-fold tha anticipated consumption level of food products potentially containing CP4 EPSPS protein. CP4 EPSPS does not pose any important allergen concerns because this protein does not possess characteristics typical of allergenic proteins. These data, in combination with seed compositional analysis and animal feeding studies, support the conclusion that glyphosate-tolerant soybean are as safe and nutritious as traditional soybeans currently being marketed.
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20
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Abstract
The average size of acoustic scatterers and the integrated backscatter coefficient of kidney cortex were measured in vivo from 2-4 MHz for a group of 50 normal adult volunteers. Our goal was to determine the sensitivity of the ultrasonic measurements under clinical conditions by identifying biologic sources of estimation uncertainty. Based on 10 measurements on each kidney of each volunteer, the average glomerular diameter for the group was found to be 216 +/- 27 microns (SD). Glomerular size was found to correlate with body surface area (r = 0.4), and the ratio of glomerular surface area to body surface area (GSA/BSA) was found to be constant throughout normal adult life with GSA/BSA = (8.24 +/- 1.35) x 10(-8) (SD). These results are consistent with histologic analyses found in the literature. Within an individual, 7% standard errors in GSA/BSA are typical. Biologic variability dominates the variance in scatterer size estimates in a group not matched for BSA, where it accounts for 47% of the variance. In a group of individuals matched for BSA, biologic variability accounts for only 21% of the variance; day-to-day variability accounts for 35% of the variance; and experimental parameters account for the remainder. If a deviation greater than 2 x SD is considered abnormal, then this technique can potentially detect changes in glomerular diameter as small as 30 microns within an individual. To detect abnormal GSA/BSA values for an individual, GSA/BSA would have to differ from the mean for that group by about 3.6 x 10(-8) or about 40%. Therefore, at this time scatterer size estimates appear most reliable for tracking the progression of disease and treatment for an individual over time.
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Affiliation(s)
- T J Hall
- Department of Radiology, University of Kansas Medical Center, Kansas City 66160-7234, USA
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21
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Cox GG, Cook LT, Insana MF, McFadden MA, Hall TJ, Harrison LA, Eckard DA, Martin NL. The effects of lossy compression on the detection of subtle pulmonary nodules. Med Phys 1996; 23:127-32. [PMID: 8700023 DOI: 10.1118/1.597691] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.6] [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: 02/01/2023] Open
Abstract
We examined the ability of radiologists to detect pulmonary nodules in computed radiographic (CR) chest images subjected to lossy image compression. Low-contrast 1-cm diameter targets simulating noncalcified pulmonary nodules were introduced into clinical images and presented to ten radiologists in a series of two-alternative forced-choice (2AFC) observer experiments. The percentages of correct observer responses obtained while viewing noncompressed images (1:1) were compared with those obtained for the same images compressed 7:1, 16:1, 44:1, and 127:1. The images were compressed using a standard full-frame discrete cosine transform (DCT) technique. The degree of compression was determined by quantizing Fourier components in various frequency channels and then Huffman encoding the result. The data show a measurable decline in performance for each compression ratio. Through signal-to-noise ratio (SNR) analysis, we found that the reduction in performance was due primarily to the compression algorithm that increased image noise in the frequency channels of the signals to be detected.
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Affiliation(s)
- G G Cox
- Department of Radiology, University of Kansas Medical Center, Kansas 66160-7234, USA
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22
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Abstract
In helical portal venous blood flow, the usual laminar flow in the portal vein is replaced by a spiral. This changes the color Doppler ultrasound (US) appearance to one of alternating or parallel red and blue bands. Duplex US may appear to show hepatopetal, hepatofugal, or simultaneous bidirectional flow depending on placement of the cursor within the helix. Helical portal venous flow is unusual in normal individuals (2.2% of 135 patients). Its presence should prompt further scrutiny for signs of liver disease, particularly portosystemic shunts, as in 20% of 41 patients who subsequently underwent liver transplantation. It is a normal finding immediately after liver transplantation (43% of 35 patients) and transjugular intrahepatic portosystemic shunt (TIPS) creation (28% of 36 patients). In both liver transplant and TIPS recipients, helical flow is usually transient. Its persistence long after transplantation in association with a prolonged increase in portal venous velocity is a useful sign of portal vein stenosis. Helical flow may also occur in cases of neoplastic invasion or displacement of the portal vein.
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Affiliation(s)
- S J Rosenthal
- Department of Radiology, University of Kansas Medical Center, Kansas City 66160-7234, USA
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23
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Hall TJ, Insana MF, Harrison LA, Soller NM, Schlehr KJ. Ultrasound contrast-detail analysis: a comparison of low-contrast detectability among scanhead designs. Med Phys 1995; 22:1117-25. [PMID: 7565387 DOI: 10.1118/1.597505] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [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: 01/26/2023] Open
Abstract
Contrast-detail (CD) analysis was used to compare the low-contrast detection capabilities of expert observers using different array-type scanhead technologies. Five expert observers viewed five different contrast targets to obtain CD curves for each scanhead. Differences in CD curves are interpreted in terms of the image contrast, resolution, and noise. It was found that differences in low-contrast detectability were due to differences in beam properties. Clinical images obtained during patient examinations are used to show how some clinically relevant tasks are distributed in their contrast and size.
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Affiliation(s)
- T J Hall
- Department of Radiology, University of Kansas Medical Center, Kansas City 66160-7234, USA
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24
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Abstract
Herniography is an accurate means of identifying groin hernias when the clinical diagnosis is uncertain. Its role in evaluation of other types of ventral hernias is less clear; however, with minor modifications in technique, herniography is also useful in these cases. This article reviews the technique of herniography, normal variations in anatomy, and interpretation of herniograms of the groin and anterior abdominal wall on the basis of 72 patients studied over 3 1/2 years. Herniography is also compared with cross-sectional imaging techniques. Inguinal and femoral hernias are best shown and classified with herniography. Ventral hernias are well demonstrated by both herniography and cross-sectional imaging; however, herniation of only fat and supine imaging may lead to misdiagnosis with computed tomography or ultrasound. Spigelian hernias are probably best depicted with cross-sectional imaging. Diagnostic pitfalls of herniography are reviewed, including the need for obtaining postexercise radiographs, oblique radiographs, and tangential radiographs.
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Affiliation(s)
- L A Harrison
- Department of Radiology, University of Kansas Medical Center, Kansas City 66160-7234, USA
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25
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John Murray P, Harrison LA, Johnson MR, Robertson GM, Scopes DI, Bull DR, Graham EA, Hayes AG, Kilpatrick GJ, Daas ID, Large C, Sheehan MJ, Stubbs CM, Turpin MP. A novel series of arylpiperazines with high affinity and selectivity for the dopamine D3 receptor. Bioorg Med Chem Lett 1995. [DOI: 10.1016/0960-894x(95)00011-h] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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26
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Insana MF, Wood JG, Hall TJ, Cox GG, Harrison LA. Effects of endothelin-1 on renal microvasculature measured using quantitative ultrasound. Ultrasound Med Biol 1995; 21:1143-51. [PMID: 8849829 DOI: 10.1016/0301-5629(95)02008-x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/15/2023]
Abstract
Renal vascular resistance is an important feature of kidney function and disease. To maintain adequate blood flow, renal vascular resistance varies in response to changes in systemic pressure. Vascular resistance is largely determined by arteriolar diameter, which is regulated by local and systemic factors. We used quantitative ultrasound techniques to follow renal vascular changes in anesthetized dogs during local intraarterial infusion of a potent vasoconstrictor, endothelin-1 (ET-1). Average arteriolar diameters were estimated by analyzing echo-signal spectra (5-15 MHz) obtained from renal cortex in vivo before, during, and after ET-1 infusion. At calculated arterial concentrations of 0.01 nM, 0.1 nM, and 1.0 nM, ET-1 reduced the average arteriolar diameter of 38 +/- 2 microns by 2%, 63%, and 91%, respectively, without producing a significant change in systemic blood pressure. Changes in scatterer size were consistent with the observed changes in renal hemodynamics detected using Doppler techniques. In addition, acoustic attenuation was found to increase with ET-1 concentration. These data suggest that quantitative ultrasound methods are sensitive to changes in renal arteriolar diameter, and may be a new noninvasive method for continuously monitoring changes in vascular resistance.
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Affiliation(s)
- M F Insana
- Department of Radiology, University of Kansas Medical Center, Kansas City, USA
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27
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Abstract
Results of a human observer performance study using a new ultrasound contrast-detail (CD) phantom are reported. The new phantom allows estimates of the fundamental statistical uncertainties involved in CD analysis. Results of these experiments show that observers generally considered to be "trained" require experience at the specific task of low-contrast target detection under signal known exactly (SKE) conditions, and that observers require an orientation period at the beginning of each observation session to obtain stable responses. The results obtained in this study can be used to estimate the number of independent images, observers, and repeat observation sessions required for a desired uncertainty in CD curves, and show that 10% fractional standard deviations are obtainable with modest observer effort.
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Affiliation(s)
- T J Hall
- Department of Radiology, University of Kansas Medical Center, Kansas City 66610-7234
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28
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Abstract
Laser film digitizers, interactive gray-scale monitors, and laser film printers are necessary to transmit digital image information. These devices must be standardized so that hard- and soft-copy images are as similar as possible. Standardization of appropriate calibration procedures is necessary to attain this goal. Radiographs are converted into digital data representations by a laser film digitizer. These representations (and those obtained with other modalities) are transferred to a laser film printer or to an interactive monitor with gray-scale display. To obtain the best gray-level fidelity, printer output optical densities should be identical to those of the input film. Laser printers should be calibrated regularly to ensure uniform results. A gray-scale controller functions as an adjunct to the host computer and can automate the calibration process. Gray-scale controller functions may someday be incorporated into an accelerator or array-processor board.
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Affiliation(s)
- E L Siegel
- Department of Diagnostic Radiology, Bell Memorial Hospital, University of Kansas Medical Center, Kansas City 66103
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29
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Templeton AW, Wetzel LH, Cook LT, Harrison LA, Eckard DA, Anderson WH, Hensley KS. Enhancement of storage phosphor plate images: a C-language program. J Digit Imaging 1992; 5:59-63. [PMID: 1554760 DOI: 10.1007/bf03167825] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [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: 12/27/2022] Open
Abstract
A C-language software program has been developed for emulating the image enhancement processing of a storage phosphor plate system. This software has been implemented on a VAX 3400 computer. There are 2,100 lines of C-language code in the program. There are seven parameters used to specify the degree of enhancement. The software is being implemented on a single accelerator board.
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Affiliation(s)
- A W Templeton
- Department of Diagnostic Radiology, University of Kansas Medical Center, Kansas City 66103
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Templeton AW, Dwyer SJ, Rosenthal SJ, Eckard DA, Harrison LA, Cook LT. A dial-up digital teleradiology system: technical considerations and clinical experience. AJR Am J Roentgenol 1991; 157:1331-6. [PMID: 1950884 DOI: 10.2214/ajr.157.6.1950884] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Affiliation(s)
- A W Templeton
- Department of Diagnostic Radiology, University of Kansas Medical Center, Kansas City 66103
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Vincent MN, Harrison LA, Brackin JM, Kovacevich PA, Mukerji P, Weller DM, Pierson EA. Genetic analysis of the antifungal activity of a soilborne Pseudomonas aureofaciens strain. Appl Environ Microbiol 1991; 57:2928-34. [PMID: 1660695 PMCID: PMC183899 DOI: 10.1128/aem.57.10.2928-2934.1991] [Citation(s) in RCA: 147] [Impact Index Per Article: 4.5] [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: 12/28/2022] Open
Abstract
Pseudomonas aureofaciens Q2-87 produces the antibiotic 2,4-diacetophloroglucinol (Phl), which inhibits Gaeumannomyces graminis var. tritici and other fungi in vitro. Strain Q2-87 also provides biological control of take-all, a root disease of wheat caused by this fungus. To assess the role of Phl in the antifungal activity of strain Q2-87, a genetic analysis of antibiotic production was conducted. Two mutants of Q2-87 with altered antifungal activity were isolated by site-directed mutagenesis with Tn5. One mutant, Q2-87::Tn5-1, did not inhibit G. graminis var. tritici in vitro and did not produce Phl. Two cosmids were isolated from a genomic library of the wild-type strain by probing with the mutant genomic fragment. Antifungal activity and Phl production were coordinately restored in Q2-87::Tn5-1 by complementation with either cosmid. Mobilization of one of these cosmids into two heterologous Pseudomonas strains conferred the ability to synthesize Phl and increased their activity against G. graminis var. tritici, Pythium ultimum, and Rhizoctonia solani in vitro. Subcloning and deletion analysis of these cosmids identified a 4.8-kb region which was necessary for Phl synthesis and antifungal activity.
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Abstract
We hypothesized that the LH response to GnRH would be greater as the interval from foaling increases, whereas the FSH response would decrease, and that corpus luteum function after the first ovulation would be similar to that after the second ovulation. At parturition, mares were assigned to receive GnRH (2 micrograms/kg) intravenously on 1) d 3 postpartum (n = 6); 2) d 6 postpartum (n = 6); 3) d 1 of first postpartum estrus (foal estrus) and again on d 1 of second postpartum estrus (n = 8). Blood was collected through an indwelling cannula at -2, -1 and 0 h relative to GnRH stimulation (basal concentrations) and at .25, .5, .75, 1.0, 1.5, 2.0, 2.5, 3.0, 3.5 and 4.0 h post-GnRH. Samples were assayed for concentrations of LH and FSH. Basal concentrations of LH were lower (P less than .05) for mares given GnRH on d 3 postpartum than for mares on d 1 of foal estrus. A rise in concentrations of LH was noted within 30 min in all groups, but the response to GnRH on d 1 of the first estrus was less (P less than .05) than on d 1 of second postpartum estrus. As the interval from parturition increased, the amount of LH secreted in response to GnRH increased. The maximum response to GnRH was greater (P less than .05) during d 1 of the first estrus than on d 3 or 6 postpartum and was greater on d 1 of cycle 2 than on d 1 of cycle 1.(ABSTRACT TRUNCATED AT 250 WORDS)
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Abstract
Natural GnRH and its analog have potential for hastening ovulation in mares. A study was conducted to evaluate the efficacy of a GnRH agonist given either as an injectable or s.c. implant for induction of ovulation in mares. Forty-five seasonally anestrous mares (March) were assigned to one of three groups (n = 15/group): 1) untreated controls; 2) i.m. injection of the GnRH agonist buserelin at 12-h intervals (40 micrograms/injection for 28 d or until ovulation) and 3) GnRH agonist administered as a s.c. implant (approximately 100 micrograms/24 h for 28 d). Six mares per group were bled on d 0, 7, 14 and 21 after injection or insertion of implant. Samples were taken at -1, -.5 and 0 h and at .5, 1, 1.5, 2, 4, 6 and 8 h after GnRH. Additional daily samples were drawn for 28 d after injection or until ovulation. Samples were assayed for concentration of LH and FSH. Progesterone concentrations were determined in samples collected on d 4, 6 and 10 after ovulation. Number and size of follicles and detection of ovulation were determined by ultrasonography. Number of mares induced to ovulate within 30 d was 0 of 15, 7 of 15 and 9 of 15 for groups 1, 2 and 3, respectively. During treatment, follicle sizes were smaller for mares in group 3 (implant). The LH response to GnRH agonist (area under curve) was similar among groups at d 0 but was greater (P less than .05) for mares in group 3 on d 7 and 14 and groups 2 and 3 on d 21 than for controls. A similar pattern was detected for peak concentrations of LH after GnRH on d 0, 7, 14 and 21. Daily concentrations of LH remained low in untreated control mares compared with GnRH-treated mares throughout the sampling period. Concentrations of LH for mares in group 3 that ovulated were elevated greatly above those for group 2 mares, whereas concentrations of FSH were similar in both treatment groups prior to ovulation.
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Affiliation(s)
- L A Harrison
- Anim. Reprod. Lab., Colorado State University, Fort Collins 80523
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Harrison LA, McMillan JH, Batnitzky S, Kepes JJ. MR appearance of an ectopic intraspinal adrenal cortical adenoma. AJNR Am J Neuroradiol 1990; 11:1185-7. [PMID: 2124054 PMCID: PMC8332118] [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: 12/30/2022]
Affiliation(s)
- L A Harrison
- Department of Diagnostic Radiology, University of Kansas Medical Center, Kansas City 66103
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McKinnon AO, Squires EL, Harrison LA, Blach EL, Shideler RK. Ultrasonographic studies on the reproductive tract of mares after parturition: effect of involution and uterine fluid on pregnancy rates in mares with normal and delayed first postpartum ovulatory cycles. J Am Vet Med Assoc 1988; 192:350-3. [PMID: 3281921] [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: 01/05/2023]
Abstract
During breeding of mares, ultrasonographic detection of uterine fluid accumulations in the first postpartum ovulatory period was associated with significantly decreased pregnancy rates, when compared with rates in control mares (P less than 0.005). The previously gravid uterine horn was recognized as the larger horn, when assessed for size by ultrasonography, for a mean of 21 days (range, 15 to 25 days) after parturition. On the basis of similar measurements obtained during 3 ultrasonographic scans (5-day period), uterine involution was determined to be completed in a mean of 23 days (range, 13 to 29 days). Progestin treatment did not affect uterine size, fluid accumulation, or rate of involution after parturition. However, delaying the first postpartum ovulation with 8 days of progestin treatment significantly improved pregnancy rates (P less than 0.05). More (P less than 0.05) mares became pregnant (23 of 28, 82%) when ovulation occurred after day 15 in the first postpartum ovulatory period, compared with those mares that ovulated before day 15 (6 of 12, 50%). We concluded that ultrasonographic detection of uterine fluid and postpartum progestin treatment can be used to manipulate breeding strategies and to improve pregnancy rates in mares bred during the first postpartum ovulatory period.
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Affiliation(s)
- A O McKinnon
- College of Veterinary Medicine and Biomedical Sciences, Colorado State University, Fort Collins 80523
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Abstract
To determine the concentrations and molecular forms of urinary IgA in IgA nephropathy and Henoch-Schoenlein purpura, we studied 29 patients with these IgA-associated renal diseases (IgAN). Control groups comprised 10 patients with other diverse renal disease and 11 healthy volunteers. Urinary IgA and IgG concentrations were higher in IgAN than in either control group and correlated positively with the serum creatinine concentration as well as the urinary protein excretion (P less than 0.01). However, IgA/IgG ratios did not differ among the three groups. Polymeric IgA (p-IgA) in the urine predominated only in normals; in IgAN and patients with other renal diseases, monomeric IgA (m-IgA) occurred almost exclusively. Serum IgA concentrations were generally normal in IgAN; four patients had concentrations greater than 500 mg/dl. Although the fraction of p-IgA in serum (median, 18%) was increased above normal (5-10%) in 13 of 16 (81%) subjects, neither the concentration of IgA or IgG nor the amount of p-IgA correlated with the serum creatinine concentration. These data suggest that the molecular form and concentration of urinary IgA are not discriminating for IgAN and are independent of these characteristics of serum IgA.
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Jackman WM, Friday KJ, Scherlag BJ, Dehning MM, Schechter E, Reynolds DW, Olson EG, Berbari EJ, Harrison LA, Lazzara R. Direct endocardial recording from an accessory atrioventricular pathway: localization of the site of block, effect of antiarrhythmic drugs, and attempt at nonsurgical ablation. Circulation 1983; 68:906-16. [PMID: 6604589 DOI: 10.1161/01.cir.68.5.906] [Citation(s) in RCA: 71] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
We recorded a discrete 0.95 mV potential consistent with accessory atrioventricular pathway (AP) activation during serial electrophysiologic studies in a patient with Ebstein's anomaly and Wolff-Parkinson-White syndrome. Bipolar pacing from the catheter electrode in which the AP potential was recorded resulted in a stimulus-ventricle interval identical to the AP-ventricle interval during antegrade conduction, and a stimulus-atrium interval identical to the AP-atrium interval during retrograde conduction. With the patient in the drug-free state, antegrade AP block during atrial pacing and retrograde AP block during ventricular pacing occurred distal to the AP potential (AP-ventricle junction and AP-atrium junction, respectively), supporting the "impedance mismatch" hypothesis. Procainamide and disopyramide each lengthened the antegrade AP effective refractory period by affecting the AP-ventricle junction (possibly by decreasing the current generated by the AP). Both drugs also lengthened the retrograde AP effective refractory period but produced a greater effect on the ventricle-AP junction than on the AP-atrium junction, suggesting marginal geometry of the former. R wave synchronous shocks of 160 and 320 W-sec delivered between the catheter electrode recording the largest unipolar AP potential and a skin electrode produced transient, complete, antegrade block over the AP, suggesting the feasibility of this new nonsurgical technique for AP ablation.
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Klein GJ, Ideker RE, Smith WM, Harrison LA, Kasell J, Wallace AG, Gallagher JJ. Epicardial mapping of the onset of ventricular tachycardia initiated by programmed stimulation in the canine heart with chronic infarction. Circulation 1979; 60:1375-84. [PMID: 498465 DOI: 10.1161/01.cir.60.6.1375] [Citation(s) in RCA: 45] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
The initial beats of ventricular tachycardia (VT) induced by programmed stimulation (PS) of the heart have frequently been observed to differ in QRS configuration from the subsequent uniform QRS complexes of tachycardia. The transient nature of these initial beats has made their study difficult during epicardial mapping with conventional, hand-held recording electrodes. Twenty-four dogs were studied with PS 1-10 months after coronary ligation. Twenty-six epicardial electrograms were recorded simultaneously during PS. The data were digitized for computer generation of isochronic maps for any desired beat. Three patterns of initiation were observed in episodes of tachycardia in which the initial beats differed from the subsequent beats of VT (11 of 18 runs of VT). Most frequently, the initial beats of VT originated near the pacing electrode before moving to a stable infarction zone location. Less frequently, the initial beats were due to transient reentry in the bundle branches or a transient shifting of early breakthrough sites in the infarction zone.
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Ideker RE, Smith WM, Wallace AG, Kasell J, Harrison LA, Klein GJ, Kinicki RE, Gallagher JJ. A computerized method for the rapid display of ventricular activation during the intraoperative study of arrhythmias. Circulation 1979; 59:449-58. [PMID: 761326 DOI: 10.1161/01.cir.59.3.449] [Citation(s) in RCA: 74] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
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Borer JS, Harrison LA, Kent KM, Levy R, Goldstein RE, Epstein SE. Beneficial effect of lidocaine on ventricular electrical stability and spontaneous ventricular fibrillation during experimental myocardial infarction. Am J Cardiol 1976; 37:860-3. [PMID: 1266751 DOI: 10.1016/0002-9149(76)90110-7] [Citation(s) in RCA: 36] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Several studies have questioned the efficacy of lidocaine in reducing the incidence of ventricular fibrillation shortly after acute myocardial infarction when arrhythmogenic mechanisms may be different from those operative several hours later. To determine whether lidocaine inhibits the occurrence of early ventricular fibrillation, the left anterior descending and septal coronary arteries were occluded at their origins in open chest anesthetized dogs. Fourteen of 16 control dogs died with ventricular fibrillation. Fifteen dogs received two different dose regimens of lidocaine before coronary occlusion. Of the 11 treated dogs maintaining lidocaine bl), 6 survived (P less than 0.05). Five dogs received the larger dose; all died, four having blood levels of 6.3 mug/ml or greater at the time of death. Ventricular fibrillation threshold also increased in six of eight dogs when lidocaine was administered after coronary occlusion. It is concluded that lidocaine at blood levels of 1.2 to 5.5 mug/ml significantly reduces the incidence of ventricular fibrillation early after coronary occlusion. Administration of this agent therefore may be of particular value in the early phase of acute myocardial infarction.
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Abstract
Recently we demonstrated that vagal stimulation increases ventricular fibrillation threshold (VFT) and decreases the incidence of spontaneous ventricular fibrillation during acute coronary occlusion. Assuming this protective effect of the vagus to be mediated through acetylcholine release, we hypothesized that inhibition of acetylcholinesterase, a potential clinical intervention, would also enhance electrical stability of acutely ischemic myocardium. A balloon cuff was placed around the left anterior descending coronary artery (LAD) and left ventricular and atrial electrodes were implanted in 10 dogs. Five to seven days later VFT was determined (VFT was defined as the minimum current required to produce ventricular fibrillation). During nonischemic conditions VFT was 42 ± 8 ma; when edrophonium was infused (1-2 mg/kg/min), VFT increased to 77 ± 11 ma (
P
< 0.005). During ischemia induced by LAD occlusion VFT fell to 19 ± 4 ma. Edrophonium increased VFT during ischemia to 52 ± 13 ma (
P
< 0.005), a level not significantly different from preischemic values. These results suggest that enhanced electrical stability of ventricular myocardium produced by vagal stimulation is mediated by acetylcholine release, and that inhibitors of acetylcholinesterase may provide a new means of therapy for arrhythmias occurring during acute myocardial ischemia.
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Abstract
The purpose of these experiments was to examine the effects of norepinephrine and propranolol on distal Purkinje fibers of the canine heart. Previous studies have indicated that action potential duration is normally greatest in distal Purkinje fibers 3-4 mm from the Purkinje-muscle junction. In such preparations, premature beats initiated either proximal or distal to the area of maximal action potential duration may propagate with delay or block. Our experiments were performed on the right bundle branch and the distal Purkinje fibers of dog hearts and used standard microelectrode techniques. Premature beats with a coupling interval comparable to the duration of action potentials at the area of maximal duration were conducted with delay. Earlier beats were confined to fibers proximal to the area of maximal action potential duration. Norepinephrine (1 x 10
-5
M
) increased action potential duration in some fibers, consistently prolonged the functional refractory period of distal Purkinje fibers, and produced a marked delay in the propagation of early premature beats. Propranolol (0.25-1.0 mg/liter) shortened action potential duration, shortened the functional refractory period of distal fibers, and reduced or abolished conduction delay and block of early premature beats. These observations suggest that the unique properties of the Purkinje-muscle junction may contribute to the genesis of arrhythmias and that this region is an important site of action of propranolol. The action of propranolol on the Purkinje-muscle junction was dose dependent.
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Harrison LA, Jacobson ED. Gastrointestinal hormones. J Okla State Med Assoc 1970; 63:157-61. [PMID: 5511587] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
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Harrison LA, Blaschke J, Phillips RS, Price WE, Cotton MD, Jacobson ED. Effects of ouabain on the splanchnic circulation. J Pharmacol Exp Ther 1969; 169:321-7. [PMID: 5824612] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
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