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Bartlett KE, Hall SR, Rasmussen SA, Crittenden E, Dawson CA, Albulescu LO, Laprade W, Harrison RA, Saviola AJ, Modahl CM, Jenkins TP, Wilkinson MC, Gutiérrez JM, Casewell NR. Dermonecrosis caused by a spitting cobra snakebite results from toxin potentiation and is prevented by the repurposed drug varespladib. Proc Natl Acad Sci U S A 2024; 121:e2315597121. [PMID: 38687786 PMCID: PMC11087757 DOI: 10.1073/pnas.2315597121] [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] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2023] [Accepted: 02/26/2024] [Indexed: 05/02/2024] Open
Abstract
Snakebite envenoming is a neglected tropical disease that causes substantial mortality and morbidity globally. The venom of African spitting cobras often causes permanent injury via tissue-destructive dermonecrosis at the bite site, which is ineffectively treated by current antivenoms. To address this therapeutic gap, we identified the etiological venom toxins in Naja nigricollis venom responsible for causing local dermonecrosis. While cytotoxic three-finger toxins were primarily responsible for causing spitting cobra cytotoxicity in cultured keratinocytes, their potentiation by phospholipases A2 toxins was essential to cause dermonecrosis in vivo. This evidence of probable toxin synergism suggests that a single toxin-family inhibiting drug could prevent local envenoming. We show that local injection with the repurposed phospholipase A2-inhibiting drug varespladib significantly prevents local tissue damage caused by several spitting cobra venoms in murine models of envenoming. Our findings therefore provide a therapeutic strategy that may effectively prevent life-changing morbidity caused by snakebite in rural Africa.
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Affiliation(s)
- Keirah E. Bartlett
- Centre for Snakebite Research & Interventions, Department of Tropical Disease Biology, Liverpool School of Tropical Medicine, LiverpoolL3 5QA, United Kingdom
| | - Steven R. Hall
- Centre for Snakebite Research & Interventions, Department of Tropical Disease Biology, Liverpool School of Tropical Medicine, LiverpoolL3 5QA, United Kingdom
- Centre for Drugs & Diagnostics, Department of Tropical Disease Biology, Liverpool School of Tropical Medicine, LiverpoolL3 5QA, United Kingdom
| | - Sean A. Rasmussen
- Department of Pathology and Laboratory Medicine, Queen Elizabeth II Health Sciences Centre and Dalhousie University, Halifax, NSB3H 1V8, Canada
| | - Edouard Crittenden
- Centre for Snakebite Research & Interventions, Department of Tropical Disease Biology, Liverpool School of Tropical Medicine, LiverpoolL3 5QA, United Kingdom
| | - Charlotte A. Dawson
- Centre for Snakebite Research & Interventions, Department of Tropical Disease Biology, Liverpool School of Tropical Medicine, LiverpoolL3 5QA, United Kingdom
| | - Laura-Oana Albulescu
- Centre for Snakebite Research & Interventions, Department of Tropical Disease Biology, Liverpool School of Tropical Medicine, LiverpoolL3 5QA, United Kingdom
- Centre for Drugs & Diagnostics, Department of Tropical Disease Biology, Liverpool School of Tropical Medicine, LiverpoolL3 5QA, United Kingdom
| | - William Laprade
- Department of Applied Mathematics and Computer Science, Technical University of Denmark, Kongens LyngbyDK-2800, Denmark
| | - Robert A. Harrison
- Centre for Snakebite Research & Interventions, Department of Tropical Disease Biology, Liverpool School of Tropical Medicine, LiverpoolL3 5QA, United Kingdom
- Centre for Drugs & Diagnostics, Department of Tropical Disease Biology, Liverpool School of Tropical Medicine, LiverpoolL3 5QA, United Kingdom
| | - Anthony J. Saviola
- Department of Biochemistry and Molecular Genetics, University of Colorado Denver, Aurora, CO80045
| | - Cassandra M. Modahl
- Centre for Snakebite Research & Interventions, Department of Tropical Disease Biology, Liverpool School of Tropical Medicine, LiverpoolL3 5QA, United Kingdom
| | - Timothy P. Jenkins
- Department of Biotechnology and Biomedicine, Technical University of Denmark, Kongens LyngbyDK-2800, Denmark
| | - Mark C. Wilkinson
- Centre for Snakebite Research & Interventions, Department of Tropical Disease Biology, Liverpool School of Tropical Medicine, LiverpoolL3 5QA, United Kingdom
| | - José María Gutiérrez
- Instituto Clodomiro Picado, Facultad de Microbiología, Universidad de Costa Rica, San José11501–2060, Costa Rica
| | - Nicholas R. Casewell
- Centre for Snakebite Research & Interventions, Department of Tropical Disease Biology, Liverpool School of Tropical Medicine, LiverpoolL3 5QA, United Kingdom
- Centre for Drugs & Diagnostics, Department of Tropical Disease Biology, Liverpool School of Tropical Medicine, LiverpoolL3 5QA, United Kingdom
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2
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Yap MKK, Modahl CM, Hall SR. Editorial: Experimental and computational aspects of bioactive proteins from animal venoms: an insight into pharmacological properties and drug discovery. Front Pharmacol 2024; 15:1380193. [PMID: 38434707 PMCID: PMC10904634 DOI: 10.3389/fphar.2024.1380193] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2024] [Accepted: 02/13/2024] [Indexed: 03/05/2024] Open
Affiliation(s)
| | - Cassandra M. Modahl
- Centre for Snakebite Research and Interventions, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
| | - Steven R. Hall
- Lancaster Medical School and Biomedical and Life Sciences, Lancaster University, Lancaster, United Kingdom
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3
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Hall SR, Rasmussen SA, Crittenden E, Dawson CA, Bartlett KE, Westhorpe AP, Albulescu LO, Kool J, Gutiérrez JM, Casewell NR. Repurposed drugs and their combinations prevent morbidity-inducing dermonecrosis caused by diverse cytotoxic snake venoms. Nat Commun 2023; 14:7812. [PMID: 38097534 PMCID: PMC10721902 DOI: 10.1038/s41467-023-43510-w] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [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: 05/24/2022] [Accepted: 11/11/2023] [Indexed: 12/17/2023] Open
Abstract
Morbidity from snakebite envenoming affects approximately 400,000 people annually. Tissue damage at the bite-site often leaves victims with catastrophic life-long injuries and is largely untreatable by current antivenoms. Repurposed small molecule drugs that inhibit specific snake venom toxins show considerable promise for tackling this neglected tropical disease. Using human skin cell assays as an initial model for snakebite-induced dermonecrosis, we show that the drugs 2,3-dimercapto-1-propanesulfonic acid (DMPS), marimastat, and varespladib, alone or in combination, inhibit the cytotoxicity of a broad range of medically important snake venoms. Thereafter, using preclinical mouse models of dermonecrosis, we demonstrate that the dual therapeutic combinations of DMPS or marimastat with varespladib significantly inhibit the dermonecrotic activity of geographically distinct and medically important snake venoms, even when the drug combinations are delivered one hour after envenoming. These findings strongly support the future translation of repurposed drug combinations as broad-spectrum therapeutics for preventing morbidity caused by snakebite.
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Affiliation(s)
- Steven R Hall
- Centre for Snakebite Research & Interventions, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, L3 5QA, UK
- Centre for Drugs & Diagnostics, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, L3 5QA, UK
| | - Sean A Rasmussen
- Department of Pathology and Laboratory Medicine, Queen Elizabeth II Health Sciences Centre and Dalhousie University, 7th Floor of MacKenzie Building, 5788 University Avenue, Halifax, NS, B3H 1V8, Canada
| | - Edouard Crittenden
- Centre for Snakebite Research & Interventions, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, L3 5QA, UK
| | - Charlotte A Dawson
- Centre for Snakebite Research & Interventions, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, L3 5QA, UK
| | - Keirah E Bartlett
- Centre for Snakebite Research & Interventions, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, L3 5QA, UK
| | - Adam P Westhorpe
- Centre for Snakebite Research & Interventions, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, L3 5QA, UK
| | - Laura-Oana Albulescu
- Centre for Snakebite Research & Interventions, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, L3 5QA, UK
- Centre for Drugs & Diagnostics, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, L3 5QA, UK
| | - Jeroen Kool
- Division of BioAnalytical Chemistry, Amsterdam Institute of Molecular and Life Sciences (AIMMS), Vrije Universiteit Amsterdam, De Boelelaan 1085, 1081 HV, Amsterdam, The Netherlands
- Centre for Analytical Sciences Amsterdam (CASA), 1098 XH, Amsterdam, The Netherlands
| | - José María Gutiérrez
- Instituto Clodomiro Picado, Facultad de Microbiología, Universidad de Costa Rica, PO Box 11501-2060, San José, Costa Rica
| | - Nicholas R Casewell
- Centre for Snakebite Research & Interventions, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, L3 5QA, UK.
- Centre for Drugs & Diagnostics, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, L3 5QA, UK.
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4
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Laprade W, Bartlett KE, Christensen CR, Kazandjian TD, Patel RN, Crittenden E, Dawson CA, Mansourvar M, Wolff DS, Fryer T, Laustsen AH, Casewell NR, Gutiérrez JM, Hall SR, Jenkins TP. Machine-learning guided Venom Induced Dermonecrosis Analysis tooL: VIDAL. Sci Rep 2023; 13:21662. [PMID: 38066189 PMCID: PMC10709447 DOI: 10.1038/s41598-023-49011-6] [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] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2023] [Accepted: 12/02/2023] [Indexed: 12/18/2023] Open
Abstract
Snakebite envenoming is a global public health issue that causes significant morbidity and mortality, particularly in low-income regions of the world. The clinical manifestations of envenomings vary depending on the snake's venom, with paralysis, haemorrhage, and necrosis being the most common and medically relevant effects. To assess the efficacy of antivenoms against dermonecrosis, a preclinical testing approach involves in vivo mouse models that mimic local tissue effects of cytotoxic snakebites in humans. However, current methods for assessing necrosis severity are time-consuming and susceptible to human error. To address this, we present the Venom Induced Dermonecrosis Analysis tooL (VIDAL), a machine-learning-guided image-based solution that can automatically identify dermonecrotic lesions in mice, adjust for lighting biases, scale the image, extract lesion area and discolouration, and calculate the severity of dermonecrosis. We also introduce a new unit, the dermonecrotic unit (DnU), to better capture the complexity of dermonecrosis severity. Our tool is comparable to the performance of state-of-the-art histopathological analysis, making it an accessible, accurate, and reproducible method for assessing dermonecrosis in mice. Given the urgent need to address the neglected tropical disease that is snakebite, high-throughput technologies such as VIDAL are crucial in developing and validating new and existing therapeutics for this debilitating disease.
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Affiliation(s)
- William Laprade
- Department of Applied Mathematics and Computer Science, Technical University of Denmark, Kongens Lyngby, Denmark
| | - Keirah E Bartlett
- Centre for Snakebite Research and Interventions, Liverpool School of Tropical Medicine, Liverpool, UK
| | - Charlotte R Christensen
- Department of Biotechnology and Biomedicine, Technical University of Denmark, Kongens Lyngby, Denmark
| | - Taline D Kazandjian
- Centre for Snakebite Research and Interventions, Liverpool School of Tropical Medicine, Liverpool, UK
| | - Rohit N Patel
- Centre for Snakebite Research and Interventions, Liverpool School of Tropical Medicine, Liverpool, UK
| | - Edouard Crittenden
- Centre for Snakebite Research and Interventions, Liverpool School of Tropical Medicine, Liverpool, UK
| | - Charlotte A Dawson
- Centre for Snakebite Research and Interventions, Liverpool School of Tropical Medicine, Liverpool, UK
| | - Marjan Mansourvar
- Department of Biotechnology and Biomedicine, Technical University of Denmark, Kongens Lyngby, Denmark
| | - Darian S Wolff
- Department of Biotechnology and Biomedicine, Technical University of Denmark, Kongens Lyngby, Denmark
| | - Thomas Fryer
- Department of Biotechnology and Biomedicine, Technical University of Denmark, Kongens Lyngby, Denmark
| | - Andreas H Laustsen
- Department of Biotechnology and Biomedicine, Technical University of Denmark, Kongens Lyngby, Denmark
| | - Nicholas R Casewell
- Centre for Snakebite Research and Interventions, Liverpool School of Tropical Medicine, Liverpool, UK
| | - José María Gutiérrez
- Instituto Clodomiro Picado, Facultad de Microbiología, Universidad de Costa Rica, San José, Costa Rica
| | - Steven R Hall
- Centre for Snakebite Research and Interventions, Liverpool School of Tropical Medicine, Liverpool, UK.
- Lancaster Medical School and Biomedical & Life Sciences, Lancaster University, Lancaster, UK.
| | - Timothy P Jenkins
- Department of Biotechnology and Biomedicine, Technical University of Denmark, Kongens Lyngby, Denmark.
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5
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McKeown BT, Relja NJ, Hall SR, Gebremeskel S, MacLeod JM, Veinotte CJ, Bennett LG, Ohlund LB, Sleno L, Jakeman DL, Berman JN, Johnston B, Goralski KB. Correction: Pilot study of jadomycin B pharmacokinetics and anti-tumoral effects in zebrafish larvae and mouse breast cancer xenograft models. Can J Physiol Pharmacol 2023; 101:214. [PMID: 36847292 DOI: 10.1139/cjpp-2023-0026] [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: 03/01/2023]
Affiliation(s)
- Brendan T McKeown
- Department of Pharmacology, Faculty of Medicine, Dalhousie University, Halifax, NS B3H 4R2, Canada.,Beatrice Hunter Cancer Research Institute, Halifax, NS B3H 4R2, Canada
| | - Nicholas J Relja
- Faculty of Health, College of Pharmacy, Dalhousie University, Halifax, NS B3H 4R2, Canada
| | - Steven R Hall
- Department of Pharmacology, Faculty of Medicine, Dalhousie University, Halifax, NS B3H 4R2, Canada
| | - Simon Gebremeskel
- Department of Microbiology & Immunology, Faculty of Medicine, Dalhousie University, Halifax NS B3H 4R2, Canada
| | - Jeanna M MacLeod
- Faculty of Health, College of Pharmacy, Dalhousie University, Halifax, NS B3H 4R2, Canada
| | - Chansey J Veinotte
- Division of Pediatric Hematology/Oncology, Department of Pediatrics, IWK Health Centre, Halifax, NS B3K 6R8, Canada
| | - Leah G Bennett
- Faculty of Health, College of Pharmacy, Dalhousie University, Halifax, NS B3H 4R2, Canada
| | - Leanne B Ohlund
- Chemistry department/CERMO-FC, Faculty of Sciences, Université du Québec à Montréal, Montréal, QC H2X 2J6, Canada
| | - Lekha Sleno
- Chemistry department/CERMO-FC, Faculty of Sciences, Université du Québec à Montréal, Montréal, QC H2X 2J6, Canada
| | - David L Jakeman
- Faculty of Health, College of Pharmacy, Dalhousie University, Halifax, NS B3H 4R2, Canada.,Department of Chemistry, Faculty of Science, Dalhousie University, Halifax, NS B3H 4R2, Canada
| | - Jason N Berman
- Division of Pediatric Hematology/Oncology, Department of Pediatrics, IWK Health Centre, Halifax, NS B3K 6R8, Canada.,Children's Hospital of Eastern Ontario Research Institute and Department of Pediatrics, University of Ottawa, Ottawa, ON K1H 5B2, Canada.,Department of Pediatrics, Faculty of Medicine, Dalhousie University, Halifax, NS B3H 4R2, Canada
| | - Brent Johnston
- Beatrice Hunter Cancer Research Institute, Halifax, NS B3H 4R2, Canada.,Department of Microbiology & Immunology, Faculty of Medicine, Dalhousie University, Halifax NS B3H 4R2, Canada.,Department of Pathology, Faculty of Medicine, Dalhousie University, Halifax, NS B3H 4R2, Canada
| | - Kerry B Goralski
- Department of Pharmacology, Faculty of Medicine, Dalhousie University, Halifax, NS B3H 4R2, Canada.,Beatrice Hunter Cancer Research Institute, Halifax, NS B3H 4R2, Canada.,Faculty of Health, College of Pharmacy, Dalhousie University, Halifax, NS B3H 4R2, Canada.,Division of Pediatric Hematology/Oncology, Department of Pediatrics, IWK Health Centre, Halifax, NS B3K 6R8, Canada
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6
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Ahmadi S, Pachis ST, Kalogeropoulos K, McGeoghan F, Canbay V, Hall SR, Crittenden EP, Dawson CA, Bartlett KE, Gutiérrez JM, Casewell NR, Keller UAD, Laustsen AH. Proteomics and histological assessment of an organotypic model of human skin following exposure to Naja nigricollis venom. Toxicon 2022; 220:106955. [DOI: 10.1016/j.toxicon.2022.106955] [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] [Received: 08/22/2022] [Revised: 10/03/2022] [Accepted: 10/16/2022] [Indexed: 11/06/2022]
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7
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McKeown BT, Relja NJ, Hall SR, Gebremeskel S, MacLeod JM, Veinotte CJ, Bennett LG, Ohlund LB, Sleno L, Jakeman DL, Berman JN, Johnston B, Goralski KB. Pilot study of jadomycin B pharmacokinetics and anti-tumoral effects in zebrafish larvae and mouse breast cancer xenograft models. Can J Physiol Pharmacol 2022; 100:1065-1076. [PMID: 35985040 DOI: 10.1139/cjpp-2022-0152] [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] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Despite numerous therapeutic options, multidrug resistance (MDR) remains an obstacle to successful breast cancer therapy. Jadomycin B, a natural product derived from Streptomyces venezuelae ISP5230, maintains cytotoxicity in MDR human breast cancer cells. Our objectives were to evaluate the pharmacokinetics, toxicity, anti-tumoral, and anti-metastatic effects of jadomycin B in zebrafish larvae and mice. In a zebrafish larval xenograft model, jadomycin B significantly reduced the proliferation of human MDA-MB-231 cells at or below its maximum tolerated dose (40 µm). In female Balb/C mice, a single intraperitoneal dose (6 mg/kg) was rapidly absorbed with a maximum serum concentration of 3.4 ± 0.27 µm. Jadomycin B concentrations declined biphasically with an elimination half-life of 1.7 ± 0.058 h. In the 4T1 mouse mammary carcinoma model, jadomycin B (12 mg/kg every 12 h from day 6 to 15 after tumor cell injection) decreased primary tumor volume compared to vehicle control. Jadomycin B-treated mice did not exhibit weight loss, nor significant increases in biomarkers of impaired hepatic (alanine aminotransferase) and renal (creatinine) function. In conclusion, jadomycin B demonstrated a good safety profile and provided partial anti-tumoral effects, warranting further dose-escalation safety and efficacy studies in MDR breast cancer models.
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Affiliation(s)
- Brendan T McKeown
- Department of Pharmacology, Faculty of Medicine, Dalhousie University, Halifax, NS, B3H 4R2, Canada.,Beatrice Hunter Cancer Research Institute, Halifax, NS, B3H 4R2, Canada
| | - Nicholas J Relja
- Faculty of Health, College of Pharmacy, Dalhousie University, Halifax, NS, B3H 4R2, Canada
| | - Steven R Hall
- Department of Pharmacology, Faculty of Medicine, Dalhousie University, Halifax, NS, B3H 4R2, Canada
| | - Simon Gebremeskel
- Department of Microbiology & Immunology, Faculty of Medicine, Dalhousie University, Halifax, NS, B3H 4R2, Canada
| | - Jeanna M MacLeod
- Faculty of Health, College of Pharmacy, Dalhousie University, Halifax, NS, B3H 4R2, Canada
| | - Chansey J Veinotte
- Division of Pediatric Hematology/Oncology, Department of Pediatrics, IWK Health Centre, Halifax, NS, B3K 6R8, Canada
| | - Leah G Bennett
- Faculty of Health, College of Pharmacy, Dalhousie University, Halifax, NS, B3H 4R2, Canada
| | - Leanne B Ohlund
- Chemistry department/CERMO-FC, Faculty of Sciences, Université du Québec à Montréal, Montréal, QC, H2X 2J6, Canada
| | - Lekha Sleno
- Chemistry department/CERMO-FC, Faculty of Sciences, Université du Québec à Montréal, Montréal, QC, H2X 2J6, Canada
| | - David L Jakeman
- Faculty of Health, College of Pharmacy, Dalhousie University, Halifax, NS, B3H 4R2, Canada.,Department of Chemistry, Faculty of Science, Dalhousie University, Halifax, NS, B3H 4R2, Canada
| | - Jason N Berman
- Division of Pediatric Hematology/Oncology, Department of Pediatrics, IWK Health Centre, Halifax, NS, B3K 6R8, Canada.,Children's Hospital of Eastern Ontario Research Institute and Department of Pediatrics, University of Ottawa, Ottawa, ON, K1H 5B2, Canada.,Department of Pediatrics, Faculty of Medicine, Dalhousie University, Halifax, NS, B3H 4R2, Canada
| | - Brent Johnston
- Beatrice Hunter Cancer Research Institute, Halifax, NS, B3H 4R2, Canada.,Department of Microbiology & Immunology, Faculty of Medicine, Dalhousie University, Halifax, NS, B3H 4R2, Canada.,Department of Pathology, Faculty of Medicine, Dalhousie University, Halifax, NS, B3H 4R2, Canada
| | - Kerry B Goralski
- Department of Pharmacology, Faculty of Medicine, Dalhousie University, Halifax, NS, B3H 4R2, Canada.,Beatrice Hunter Cancer Research Institute, Halifax, NS, B3H 4R2, Canada.,Faculty of Health, College of Pharmacy, Dalhousie University, Halifax, NS, B3H 4R2, Canada.,Division of Pediatric Hematology/Oncology, Department of Pediatrics, IWK Health Centre, Halifax, NS, B3K 6R8, Canada
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8
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Menzies SK, Litschka-Koen T, Edge RJ, Alsolaiss J, Crittenden E, Hall SR, Westhorpe A, Thomas B, Murray J, Shongwe N, Padidar S, Lalloo DG, Casewell NR, Pons J, Harrison RA. Two snakebite antivenoms have potential to reduce Eswatini's dependency upon a single, increasingly unavailable product: Results of preclinical efficacy testing. PLoS Negl Trop Dis 2022; 16:e0010496. [PMID: 36108067 PMCID: PMC9529146 DOI: 10.1371/journal.pntd.0010496] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2022] [Revised: 10/03/2022] [Accepted: 08/15/2022] [Indexed: 11/24/2022] Open
Abstract
BACKGROUND Snakebite is a major public health concern in Eswatini, where treatment relies upon one antivenom-SAIMR Polyvalent. Although effective in treating snakebite, SAIMR Polyvalent is difficult to source outside its manufacturing country (South Africa) and is dauntingly expensive. We compared the preclinical venom-neutralising efficacy of two alternative antivenoms with that of SAIMR Polyvalent against the lethal and tissue-destructive effects of venoms from five species of medically important snakes using in vivo murine assays. The test antivenoms were 'Panafrican' manufactured by Instituto Clodomiro Picado and 'PANAF' manufactured by Premium Serums & Vaccines. PRINCIPAL FINDINGS In vivo murine preclinical studies identified both test antivenoms were equally or more effective than SAIMR Polyvalent at neutralising lethal and tissue-destructive effects of Naja mossambica venom. Both test antivenoms were less effective than SAIMR Polyvalent at neutralising the lethal effects of Bitis arietans, Dendroaspis polylepis, Hemachatus haemachatus and Naja annulifera venoms, but similarly effective at neutralising tissue damage induced by B. arietans and H. haemachatus venoms. In vitro immunological assays identified that the titres and toxin-specificities of immunoglobulins (iGs) in the test antivenoms were comparable to that of SAIMR Polyvalent. Plasma clotting disturbances by H. haemachatus and N. mossambica were neutralised by the test antivenoms, whereas SAIMR Polyvalent failed to neutralise this bioactivity of N. mossambica venom. B. arietans SVMP activity was equally reduced by all three antivenoms, and H. haemachatus and N. mossambica PLA2 activities were neutralised by all three antivenoms. CONCLUSIONS While both Panafrican and PANAF antivenoms exhibited promising preclinical efficacies, both were less poly-specifically effective than SAIMR Polyvalent in these murine assays. The efficacy of these antivenoms against the lethal and tissue-destructive effects of N. mossambica venom, the most common biting species in Eswatini, identify that Panafrican and PANAF antivenoms offer effective alternatives to SAIMR Polyvalent for the treatment of snakebite in Eswatini, and potentially for neighbouring countries.
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Affiliation(s)
- Stefanie K. Menzies
- Centre for Snakebite Research and Interventions, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
- Centre for Drugs and Diagnostics, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
| | - Thea Litschka-Koen
- Eswatini Snakebite Research and Intervention Centre, Simunye, Eswatini
- Eswatini Antivenom Foundation, Simunye, Eswatini
| | - Rebecca J. Edge
- Centre for Snakebite Research and Interventions, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
| | - Jaffer Alsolaiss
- Centre for Snakebite Research and Interventions, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
| | - Edouard Crittenden
- Centre for Snakebite Research and Interventions, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
| | - Steven R. Hall
- Centre for Snakebite Research and Interventions, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
| | - Adam Westhorpe
- Centre for Snakebite Research and Interventions, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
| | - Brent Thomas
- Centre for Snakebite Research and Interventions, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
| | - James Murray
- Eswatini Snakebite Research and Intervention Centre, Simunye, Eswatini
- Eswatini Antivenom Foundation, Simunye, Eswatini
| | - Nondusimo Shongwe
- Eswatini Snakebite Research and Intervention Centre, Simunye, Eswatini
- Eswatini Antivenom Foundation, Simunye, Eswatini
| | - Sara Padidar
- Eswatini Snakebite Research and Intervention Centre, Simunye, Eswatini
- Eswatini Antivenom Foundation, Simunye, Eswatini
- Department of Biological Sciences, University of Eswatini, Kwaluseni, Eswatini
| | - David G. Lalloo
- Department of Tropical Disease Biology, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
| | - Nicholas R. Casewell
- Centre for Snakebite Research and Interventions, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
- Centre for Drugs and Diagnostics, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
| | - Jonathan Pons
- Eswatini Snakebite Research and Intervention Centre, Simunye, Eswatini
- Eswatini Antivenom Foundation, Simunye, Eswatini
| | - Robert A. Harrison
- Centre for Snakebite Research and Interventions, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
- Centre for Drugs and Diagnostics, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
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9
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Alomran N, Blundell P, Alsolaiss J, Crittenden E, Ainsworth S, Dawson CA, Edge RJ, Hall SR, Harrison RA, Wilkinson MC, Menzies SK, Casewell NR. Exploring the Utility of Recombinant Snake Venom Serine Protease Toxins as Immunogens for Generating Experimental Snakebite Antivenoms. Toxins (Basel) 2022; 14:443. [PMID: 35878181 PMCID: PMC9319908 DOI: 10.3390/toxins14070443] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2022] [Revised: 06/22/2022] [Accepted: 06/23/2022] [Indexed: 02/01/2023] Open
Abstract
Snakebite is a neglected tropical disease that causes high rates of global mortality and morbidity. Although snakebite can cause a variety of pathologies in victims, haemotoxic effects are particularly common and are typically characterised by haemorrhage and/or venom-induced consumption coagulopathy. Despite polyclonal antibody-based antivenoms being the mainstay life-saving therapy for snakebite, they are associated with limited cross-snake species efficacy, as there is often extensive toxin variation between snake venoms, including those used as immunogens for antivenom production. This restricts the therapeutic utility of any antivenom to certain geographical regions. In this study, we explored the feasibility of using recombinantly expressed toxins as immunogens to stimulate focused, pathology-specific, antibodies in order to broadly counteract specific toxins associated with snakebite envenoming. Three snake venom serine proteases (SVSP) toxins, sourced from geographically diverse and medically important viper snake venoms, were successfully expressed in HEK293F mammalian cells and used for murine immunisation. Analyses of the resulting antibody responses revealed that ancrod and RVV-V stimulated the strongest immune responses, and that experimental antivenoms directed against these recombinant SVSP toxins, and a mixture of the three different immunogens, extensively recognised and exhibited immunological binding towards a variety of native snake venoms. While the experimental antivenoms showed some reduction in abnormal clotting parameters stimulated by the toxin immunogens and crude venom, specifically reducing the depletion of fibrinogen levels and prolongation of prothrombin times, fibrinogen degradation experiments revealed that they broadly protected against venom- and toxin-induced fibrinogenolytic functional activities. Overall, our findings further strengthen the case for the use of recombinant venom toxins as supplemental immunogens to stimulate focused and desirable antibody responses capable of neutralising venom-induced pathological effects, and therefore potentially circumventing some of the limitations associated with current snakebite therapies.
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Affiliation(s)
- Nessrin Alomran
- Centre for Snakebite Research & Interventions, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool L3 5QA, UK; (N.A.); (J.A.); (E.C.); (S.A.); (C.A.D.); (R.J.E.); (S.R.H.); (R.A.H.); (M.C.W.); (S.K.M.)
- Department of Tropical Disease Biology, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool L3 5QA, UK;
| | - Patricia Blundell
- Department of Tropical Disease Biology, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool L3 5QA, UK;
| | - Jaffer Alsolaiss
- Centre for Snakebite Research & Interventions, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool L3 5QA, UK; (N.A.); (J.A.); (E.C.); (S.A.); (C.A.D.); (R.J.E.); (S.R.H.); (R.A.H.); (M.C.W.); (S.K.M.)
- Department of Tropical Disease Biology, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool L3 5QA, UK;
| | - Edouard Crittenden
- Centre for Snakebite Research & Interventions, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool L3 5QA, UK; (N.A.); (J.A.); (E.C.); (S.A.); (C.A.D.); (R.J.E.); (S.R.H.); (R.A.H.); (M.C.W.); (S.K.M.)
- Department of Tropical Disease Biology, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool L3 5QA, UK;
| | - Stuart Ainsworth
- Centre for Snakebite Research & Interventions, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool L3 5QA, UK; (N.A.); (J.A.); (E.C.); (S.A.); (C.A.D.); (R.J.E.); (S.R.H.); (R.A.H.); (M.C.W.); (S.K.M.)
- Department of Tropical Disease Biology, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool L3 5QA, UK;
| | - Charlotte A. Dawson
- Centre for Snakebite Research & Interventions, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool L3 5QA, UK; (N.A.); (J.A.); (E.C.); (S.A.); (C.A.D.); (R.J.E.); (S.R.H.); (R.A.H.); (M.C.W.); (S.K.M.)
- Department of Tropical Disease Biology, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool L3 5QA, UK;
| | - Rebecca J. Edge
- Centre for Snakebite Research & Interventions, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool L3 5QA, UK; (N.A.); (J.A.); (E.C.); (S.A.); (C.A.D.); (R.J.E.); (S.R.H.); (R.A.H.); (M.C.W.); (S.K.M.)
- Department of Tropical Disease Biology, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool L3 5QA, UK;
| | - Steven R. Hall
- Centre for Snakebite Research & Interventions, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool L3 5QA, UK; (N.A.); (J.A.); (E.C.); (S.A.); (C.A.D.); (R.J.E.); (S.R.H.); (R.A.H.); (M.C.W.); (S.K.M.)
- Department of Tropical Disease Biology, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool L3 5QA, UK;
| | - Robert A. Harrison
- Centre for Snakebite Research & Interventions, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool L3 5QA, UK; (N.A.); (J.A.); (E.C.); (S.A.); (C.A.D.); (R.J.E.); (S.R.H.); (R.A.H.); (M.C.W.); (S.K.M.)
- Department of Tropical Disease Biology, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool L3 5QA, UK;
- Centre for Drugs and Diagnostics, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool L3 5QA, UK
| | - Mark C. Wilkinson
- Centre for Snakebite Research & Interventions, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool L3 5QA, UK; (N.A.); (J.A.); (E.C.); (S.A.); (C.A.D.); (R.J.E.); (S.R.H.); (R.A.H.); (M.C.W.); (S.K.M.)
- Department of Tropical Disease Biology, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool L3 5QA, UK;
| | - Stefanie K. Menzies
- Centre for Snakebite Research & Interventions, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool L3 5QA, UK; (N.A.); (J.A.); (E.C.); (S.A.); (C.A.D.); (R.J.E.); (S.R.H.); (R.A.H.); (M.C.W.); (S.K.M.)
- Department of Tropical Disease Biology, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool L3 5QA, UK;
| | - Nicholas R. Casewell
- Centre for Snakebite Research & Interventions, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool L3 5QA, UK; (N.A.); (J.A.); (E.C.); (S.A.); (C.A.D.); (R.J.E.); (S.R.H.); (R.A.H.); (M.C.W.); (S.K.M.)
- Department of Tropical Disease Biology, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool L3 5QA, UK;
- Centre for Drugs and Diagnostics, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool L3 5QA, UK
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Menzies SK, Clare RH, Xie C, Westhorpe A, Hall SR, Edge RJ, Alsolaiss J, Crittenden E, Marriott AE, Harrison RA, Kool J, Casewell NR. In vitro and in vivo preclinical venom inhibition assays identify metalloproteinase inhibiting drugs as potential future treatments for snakebite envenoming by Dispholidus typus. Toxicon X 2022; 14:100118. [PMID: 35321116 PMCID: PMC8935517 DOI: 10.1016/j.toxcx.2022.100118] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2021] [Revised: 02/18/2022] [Accepted: 03/07/2022] [Indexed: 11/23/2022] Open
Abstract
Snakebite envenoming affects more than 250,000 people annually in sub-Saharan Africa. Envenoming by Dispholidus typus (boomslang) results in venom-induced consumption coagulopathy (VICC), whereby highly abundant prothrombin-activating snake venom metalloproteinases (SVMPs) consume clotting factors and deplete fibrinogen. The only available treatment for D. typus envenoming is the monovalent SAIMR Boomslang antivenom. Treatment options are urgently required because this antivenom is often difficult to source and, at US$6000/vial, typically unaffordable for most snakebite patients. We therefore investigated the in vitro and in vivo preclinical efficacy of four SVMP inhibitors to neutralise the effects of D. typus venom; the matrix metalloproteinase inhibitors marimastat and prinomastat, and the metal chelators dimercaprol and DMPS. The venom of D. typus exhibited an SVMP-driven procoagulant phenotype in vitro. Marimastat and prinomastat demonstrated equipotent inhibition of the SVMP-mediated procoagulant activity of the venom in vitro, whereas dimercaprol and DMPS showed considerably lower potency. However, when tested in preclinical murine models of envenoming using mixed sex CD1 mice, DMPS and marimastat demonstrated partial protection against venom lethality, demonstrated by prolonged survival times of experimental animals, whereas dimercaprol and prinomastat failed to confer any protection at the doses tested. The preclinical results presented here demonstrate that DMPS and marimastat show potential as novel small molecule-based therapeutics for D. typus snakebite envenoming. These two drugs have been previously shown to be effective against Echis ocellatus VICC in preclinical models, and thus we conclude that marimastat and DMPS should be further explored as potentially valuable early intervention therapeutics to broadly treat VICC following snakebite envenoming in sub-Saharan Africa.
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Affiliation(s)
- Stefanie K. Menzies
- Centre for Snakebite Research and Interventions, Department of Tropical Disease Biology, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, L3 5QA, England, UK
- Centre for Drugs and Diagnostics, Department of Tropical Disease Biology, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, L3 5QA, England, UK
| | - Rachel H. Clare
- Centre for Snakebite Research and Interventions, Department of Tropical Disease Biology, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, L3 5QA, England, UK
- Centre for Drugs and Diagnostics, Department of Tropical Disease Biology, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, L3 5QA, England, UK
| | - Chunfang Xie
- Amsterdam Institute of Molecular and Life Sciences, Division of BioAnalytical Chemistry, Department of Chemistry and Pharmaceutical Sciences, Faculty of Science, Vrije Universiteit Amsterdam, De Boelelaan 1085, 1081HV, Amsterdam, the Netherlands
| | - Adam Westhorpe
- Centre for Snakebite Research and Interventions, Department of Tropical Disease Biology, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, L3 5QA, England, UK
- Centre for Drugs and Diagnostics, Department of Tropical Disease Biology, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, L3 5QA, England, UK
| | - Steven R. Hall
- Centre for Snakebite Research and Interventions, Department of Tropical Disease Biology, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, L3 5QA, England, UK
- Centre for Drugs and Diagnostics, Department of Tropical Disease Biology, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, L3 5QA, England, UK
| | - Rebecca J. Edge
- Centre for Snakebite Research and Interventions, Department of Tropical Disease Biology, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, L3 5QA, England, UK
- Centre for Drugs and Diagnostics, Department of Tropical Disease Biology, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, L3 5QA, England, UK
| | - Jaffer Alsolaiss
- Centre for Snakebite Research and Interventions, Department of Tropical Disease Biology, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, L3 5QA, England, UK
- Centre for Drugs and Diagnostics, Department of Tropical Disease Biology, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, L3 5QA, England, UK
| | - Edouard Crittenden
- Centre for Snakebite Research and Interventions, Department of Tropical Disease Biology, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, L3 5QA, England, UK
- Centre for Drugs and Diagnostics, Department of Tropical Disease Biology, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, L3 5QA, England, UK
| | - Amy E. Marriott
- Centre for Snakebite Research and Interventions, Department of Tropical Disease Biology, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, L3 5QA, England, UK
- Centre for Drugs and Diagnostics, Department of Tropical Disease Biology, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, L3 5QA, England, UK
| | - Robert A. Harrison
- Centre for Snakebite Research and Interventions, Department of Tropical Disease Biology, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, L3 5QA, England, UK
- Centre for Drugs and Diagnostics, Department of Tropical Disease Biology, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, L3 5QA, England, UK
| | - Jeroen Kool
- Amsterdam Institute of Molecular and Life Sciences, Division of BioAnalytical Chemistry, Department of Chemistry and Pharmaceutical Sciences, Faculty of Science, Vrije Universiteit Amsterdam, De Boelelaan 1085, 1081HV, Amsterdam, the Netherlands
| | - Nicholas R. Casewell
- Centre for Snakebite Research and Interventions, Department of Tropical Disease Biology, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, L3 5QA, England, UK
- Centre for Drugs and Diagnostics, Department of Tropical Disease Biology, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, L3 5QA, England, UK
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11
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Clare RH, Hall SR, Patel RN, Casewell NR. Small Molecule Drug Discovery for Neglected Tropical Snakebite. Trends Pharmacol Sci 2021; 42:340-353. [DOI: 10.1016/j.tips.2021.02.005] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2020] [Revised: 02/24/2021] [Accepted: 02/26/2021] [Indexed: 12/31/2022]
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12
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Cookman J, Hamilton V, Hall SR, Bangert U. Non-classical crystallisation pathway directly observed for a pharmaceutical crystal via liquid phase electron microscopy. Sci Rep 2020; 10:19156. [PMID: 33154480 PMCID: PMC7644682 DOI: 10.1038/s41598-020-75937-2] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2020] [Accepted: 10/22/2020] [Indexed: 12/18/2022] Open
Abstract
Non-classical crystallisation (NCC) pathways are widely accepted, however there is conflicting evidence regarding the intermediate stages of crystallisation, how they manifest and further develop into crystals. Evidence from direct observations is especially lacking for small organic molecules, as distinguishing these low-electron dense entities from their similar liquid-phase surroundings presents signal-to-noise ratio and contrast challenges. Here, Liquid Phase Electron Microscopy (LPEM) captures the intermediate pre-crystalline stages of a small organic molecule, flufenamic acid (FFA), a common pharmaceutical. High temporospatial imaging of FFA in its native environment, an organic solvent, suggests that in this system a Pre-Nucleation Cluster (PNC) pathway is followed by features exhibiting two-step nucleation. This work adds to the growing body of evidence that suggests nucleation pathways are likely an amalgamation of multiple existing non-classical theories and highlights the need for the direct evidence presented by in situ techniques such as LPEM.
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Affiliation(s)
- J Cookman
- Physics Department & Bernal Institute, University of Limerick, Castletroy, Co. Limerick, Ireland
| | - V Hamilton
- School of Chemistry, University of Bristol, Cantock's Close, Bristol, BS8 1TS, UK
| | - S R Hall
- School of Chemistry, University of Bristol, Cantock's Close, Bristol, BS8 1TS, UK.
| | - U Bangert
- Physics Department & Bernal Institute, University of Limerick, Castletroy, Co. Limerick, Ireland.
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13
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Dahn ML, Cruickshank BM, Jackson AJ, Dean C, Holloway RW, Hall SR, Coyle KM, Maillet H, Waisman DM, Goralski KB, Giacomantonio CA, Weaver ICG, Marcato P. Decitabine Response in Breast Cancer Requires Efficient Drug Processing and Is Not Limited by Multidrug Resistance. Mol Cancer Ther 2020; 19:1110-1122. [PMID: 32156786 DOI: 10.1158/1535-7163.mct-19-0745] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2019] [Revised: 01/30/2020] [Accepted: 03/05/2020] [Indexed: 11/16/2022]
Abstract
Dysregulation of DNA methylation is an established feature of breast cancers. DNA demethylating therapies like decitabine are proposed for the treatment of triple-negative breast cancers (TNBC) and indicators of response need to be identified. For this purpose, we characterized the effects of decitabine in a panel of 10 breast cancer cell lines and observed a range of sensitivity to decitabine that was not subtype specific. Knockdown of potential key effectors demonstrated the requirement of deoxycytidine kinase (DCK) for decitabine response in breast cancer cells. In treatment-naïve breast tumors, DCK was higher in TNBCs, and DCK levels were sustained or increased post chemotherapy treatment. This suggests that limited DCK levels will not be a barrier to response in patients with TNBC treated with decitabine as a second-line treatment or in a clinical trial. Methylome analysis revealed that genome-wide, region-specific, tumor suppressor gene-specific methylation, and decitabine-induced demethylation did not predict response to decitabine. Gene set enrichment analysis of transcriptome data demonstrated that decitabine induced genes within apoptosis, cell cycle, stress, and immune pathways. Induced genes included those characterized by the viral mimicry response; however, knockdown of key effectors of the pathway did not affect decitabine sensitivity suggesting that breast cancer growth suppression by decitabine is independent of viral mimicry. Finally, taxol-resistant breast cancer cells expressing high levels of multidrug resistance transporter ABCB1 remained sensitive to decitabine, suggesting that the drug could be used as second-line treatment for chemoresistant patients.
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Affiliation(s)
- Margaret L Dahn
- Department of Pathology, Dalhousie University, Halifax, Nova Scotia, Canada
| | | | - Ainsleigh J Jackson
- Department of Microbiology and Immunology, Dalhousie University, Halifax, Nova Scotia, Canada
| | - Cheryl Dean
- Department of Pathology, Dalhousie University, Halifax, Nova Scotia, Canada
| | - Ryan W Holloway
- Department of Pathology, Dalhousie University, Halifax, Nova Scotia, Canada
| | - Steven R Hall
- Department of Pharmacology, Dalhousie University, Halifax, Nova Scotia, Canada
| | - Krysta M Coyle
- Department of Pathology, Dalhousie University, Halifax, Nova Scotia, Canada
| | - Hillary Maillet
- Department of Psychology and Neuroscience, Dalhousie University, Halifax, Nova Scotia, Canada
| | - David M Waisman
- Department of Pathology, Dalhousie University, Halifax, Nova Scotia, Canada.,Department of Biochemistry and Molecular Biology, Dalhousie University, Halifax, Nova Scotia, Canada
| | - Kerry B Goralski
- Department of Pharmacology, Dalhousie University, Halifax, Nova Scotia, Canada.,College of Pharmacy, Dalhousie University, Halifax, Nova Scotia, Canada
| | - Carman A Giacomantonio
- Department of Pathology, Dalhousie University, Halifax, Nova Scotia, Canada.,Department of Surgery, Dalhousie University, Halifax, Nova Scotia, Canada
| | - Ian C G Weaver
- Department of Pathology, Dalhousie University, Halifax, Nova Scotia, Canada.,Department of Psychology and Neuroscience, Dalhousie University, Halifax, Nova Scotia, Canada.,Department of Psychiatry, Dalhousie University, Halifax, Nova Scotia, Canada.,Brain Repair Centre, Halifax, Nova Scotia, Canada
| | - Paola Marcato
- Department of Pathology, Dalhousie University, Halifax, Nova Scotia, Canada. .,Department of Microbiology and Immunology, Dalhousie University, Halifax, Nova Scotia, Canada
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14
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Tomko A, O'Leary L, Trask H, Achenbach JC, Hall SR, Goralski KB, Ellis LD, Dupré DJ. Antitumor Activity of Abnormal Cannabidiol and Its Analog O-1602 in Taxol-Resistant Preclinical Models of Breast Cancer. Front Pharmacol 2019; 10:1124. [PMID: 31611800 PMCID: PMC6777324 DOI: 10.3389/fphar.2019.01124] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2019] [Accepted: 08/30/2019] [Indexed: 12/31/2022] Open
Abstract
Cannabinoids exhibit anti-inflammatory and antitumorigenic properties. Contrary to most cannabinoids present in the Cannabis plant, some, such as O-1602 and abnormal cannabidiol, have no or only little affinity to the CB1 or CB2 cannabinoid receptors and instead exert their effects through other receptors. Here, we investigated whether the synthetic regioisomers of cannabidiol, abnormal cannabidiol, and a closely related compound, O-1602, display antitumorigenic effects in cellular models of breast cancer and whether it could reduce tumorigenesis in vivo. Several studies have shown the effects of cannabinoids on chemotherapy-sensitive breast cancer cell lines, but less is known about the antitumorigenic effects of cannabinoids in chemotherapy-resistant cell lines. Paclitaxel-resistant MDA-MB-231 and MCF-7 breast cancer cell lines were used to study the effect of O-1602 and abnormal cannabidiol on viability, apoptosis, and migration. The effects of O-1602 and abnormal cannabidiol on cell viability were completely blocked by the combination of GPR55 and GPR18-specific siRNAs. Both O-1602 and abnormal cannabidiol decreased viability in paclitaxel-resistant breast cancer cells in a concentration-dependent manner through induction of apoptosis. The effect of these cannabinoids on tumor growth in vivo was studied in a zebrafish xenograft model. In this model, treatment with O-1602 and abnormal cannabidiol (2 µM) significantly reduced tumor growth. Our results suggest that atypical cannabinoids, like O-1602 and abnormal cannabidiol, exert antitumorigenic effects on paclitaxel-resistant breast cancer cells. Due to their lack of central sedation and psychoactive effects, these atypical cannabinoids could represent new leads for the development of additional anticancer treatments when resistance to conventional chemotherapy occurs during the treatment of breast and possibly other cancers.
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Affiliation(s)
- Andrea Tomko
- Department of Pharmacology, Faculty of Medicine, Dalhousie University, Halifax, Canada
| | - Lauren O'Leary
- Department of Pharmacology, Faculty of Medicine, Dalhousie University, Halifax, Canada
| | - Hilary Trask
- Department of Pharmacology, Faculty of Medicine, Dalhousie University, Halifax, Canada
| | - John C Achenbach
- Aquatic and Crop Resource Development Research Center, National Research Council of Canada, Halifax, Canada
| | - Steven R Hall
- Department of Pharmacology, Faculty of Medicine, Dalhousie University, Halifax, Canada.,College of Pharmacy, Faculty of Health, Dalhousie University, Halifax, Canada
| | - Kerry B Goralski
- Department of Pharmacology, Faculty of Medicine, Dalhousie University, Halifax, Canada.,College of Pharmacy, Faculty of Health, Dalhousie University, Halifax, Canada
| | - Lee D Ellis
- College of Pharmacy, Faculty of Health, Dalhousie University, Halifax, Canada
| | - Denis J Dupré
- Department of Pharmacology, Faculty of Medicine, Dalhousie University, Halifax, Canada
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15
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16
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Robertson AW, MacLeod JM, MacIntyre LW, Forget SM, Hall SR, Bennett LG, Correa H, Kerr RG, Goralski KB, Jakeman DL. Post Polyketide Synthase Carbon–Carbon Bond Formation in Type-II PKS-Derived Natural Products from Streptomyces venezuelae. J Org Chem 2018; 83:1876-1890. [DOI: 10.1021/acs.joc.7b02823] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Affiliation(s)
| | | | | | | | | | | | - Hebelin Correa
- Department
of Chemistry, University of Prince Edward Island, Charlottetown, PE C1A 4P3, Canada
| | - Russell G. Kerr
- Department
of Chemistry, University of Prince Edward Island, Charlottetown, PE C1A 4P3, Canada
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17
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Hall SR, Toulany J, Bennett LG, Martinez-Farina CF, Robertson AW, Jakeman DL, Goralski KB. Jadomycins Inhibit Type II Topoisomerases and Promote DNA Damage and Apoptosis in Multidrug-Resistant Triple-Negative Breast Cancer Cells. J Pharmacol Exp Ther 2017; 363:196-210. [PMID: 28904004 DOI: 10.1124/jpet.117.241125] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2017] [Accepted: 09/07/2017] [Indexed: 12/24/2022] Open
Abstract
Jadomycins are natural products that kill drug-sensitive and multidrug-resistant (MDR) breast cancer cells. To date, the cytotoxic activity of jadomycins has never been tested in MDR breast cancer cells that are also triple negative. Additionally, there is only a rudimentary understanding of how jadomycins cause cancer cell death, which includes the induction of intracellular reactive oxygen species (ROS). We first created a paclitaxel-resistant, triple-negative breast cancer cell line [paclitaxel-resistant MDA-MB-231 breast cancer cells (231-TXL)] from drug-sensitive control MDA-MB-231 cells (231-CON). Using thiazolyl blue methyltetrazolium bromide cell viability-measuring assays, jadomycins B, S, and F were found to be equipotent in drug-sensitive 231-CON and MDR 231-TXL cells; and using ROS-detecting assays, these jadomycins were determined to increase ROS activity in both cell lines by up to 7.3-fold. Jadomycins caused DNA double-strand breaks in 231-CON and 231-TXL cells as measured by γH2AX Western blotting. Coincubation with the antioxidant N-acetyl cysteine or pro-oxidant auranofin did not affect jadomycin-mediated DNA damage. Jadomycins induced apoptosis in 231-CON and 231-TXL cells as measured by annexin V affinity assays, a process that was retained when ROS were inhibited. This indicated that jadomycins are capable of inducing MDA-MB-231 apoptotic cell death independently of ROS activity. Using quantitative polymerase chain reaction, Western blotting, and direct topoisomerase inhibition assays, it was determined that jadomycins inhibit type II topoisomerases and that jadomycins B and F selectively poison topoisomerase IIβ We therefore propose novel mechanisms through which jadomycins induce breast cancer cell death independently of ROS activity, through inhibition or poisoning of type II topoisomerases and the induction of DNA damage and apoptosis.
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Affiliation(s)
- Steven R Hall
- Department of Pharmacology, Faculty of Medicine (S.R.H., K.B.G.), College of Pharmacy, Faculty of Health (J.T., L.G.B, D.L.J., K.B.G.), and Department of Chemistry, Faculty of Sciences (C.F.M.-F., A.W.R., D.L.J.), Dalhousie University, Halifax, Nova Scotia, Canada
| | - Jay Toulany
- Department of Pharmacology, Faculty of Medicine (S.R.H., K.B.G.), College of Pharmacy, Faculty of Health (J.T., L.G.B, D.L.J., K.B.G.), and Department of Chemistry, Faculty of Sciences (C.F.M.-F., A.W.R., D.L.J.), Dalhousie University, Halifax, Nova Scotia, Canada
| | - Leah G Bennett
- Department of Pharmacology, Faculty of Medicine (S.R.H., K.B.G.), College of Pharmacy, Faculty of Health (J.T., L.G.B, D.L.J., K.B.G.), and Department of Chemistry, Faculty of Sciences (C.F.M.-F., A.W.R., D.L.J.), Dalhousie University, Halifax, Nova Scotia, Canada
| | - Camilo F Martinez-Farina
- Department of Pharmacology, Faculty of Medicine (S.R.H., K.B.G.), College of Pharmacy, Faculty of Health (J.T., L.G.B, D.L.J., K.B.G.), and Department of Chemistry, Faculty of Sciences (C.F.M.-F., A.W.R., D.L.J.), Dalhousie University, Halifax, Nova Scotia, Canada
| | - Andrew W Robertson
- Department of Pharmacology, Faculty of Medicine (S.R.H., K.B.G.), College of Pharmacy, Faculty of Health (J.T., L.G.B, D.L.J., K.B.G.), and Department of Chemistry, Faculty of Sciences (C.F.M.-F., A.W.R., D.L.J.), Dalhousie University, Halifax, Nova Scotia, Canada
| | - David L Jakeman
- Department of Pharmacology, Faculty of Medicine (S.R.H., K.B.G.), College of Pharmacy, Faculty of Health (J.T., L.G.B, D.L.J., K.B.G.), and Department of Chemistry, Faculty of Sciences (C.F.M.-F., A.W.R., D.L.J.), Dalhousie University, Halifax, Nova Scotia, Canada
| | - Kerry B Goralski
- Department of Pharmacology, Faculty of Medicine (S.R.H., K.B.G.), College of Pharmacy, Faculty of Health (J.T., L.G.B, D.L.J., K.B.G.), and Department of Chemistry, Faculty of Sciences (C.F.M.-F., A.W.R., D.L.J.), Dalhousie University, Halifax, Nova Scotia, Canada
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Pan LL, Atlas EL, Salawitch RJ, Honomichl SB, Bresch JF, Randel WJ, Apel EC, Hornbrook RS, Weinheimer AJ, Anderson DC, Andrews SJ, Baidar S, Beaton SP, Campos TL, Carpenter LJ, Chen D, Dix B, Donets V, Hall SR, Hanisco TF, Homeyer CR, Huey LG, Jensen JB, Kaser L, Kinnison DE, Koenig TK, Lamarque JF, Liu C, Luo J, Luo ZJ, Montzka DD, Nicely JM, Pierce RB, Riemer DD, Robinson T, Romashkin P, Saiz-Lopez A, Schauffler S, Shieh O, Stell MH, Ullmann K, Vaughan G, Volkamer R, Wolfe G. The Convective Transport of Active Species in the Tropics (CONTRAST) Experiment. Bull Am Meteorol Soc 2017; 98:106-128. [PMID: 29636590 PMCID: PMC5889942 DOI: 10.1175/bams-d-14-00272.1] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
The Convective Transport of Active Species in the Tropics (CONTRAST) experiment was conducted from Guam (13.5° N, 144.8° E) during January-February 2014. Using the NSF/NCAR Gulfstream V research aircraft, the experiment investigated the photochemical environment over the tropical western Pacific (TWP) warm pool, a region of massive deep convection and the major pathway for air to enter the stratosphere during Northern Hemisphere (NH) winter. The new observations provide a wealth of information for quantifying the influence of convection on the vertical distributions of active species. The airborne in situ measurements up to 15 km altitude fill a significant gap by characterizing the abundance and altitude variation of a wide suite of trace gases. These measurements, together with observations of dynamical and microphysical parameters, provide significant new data for constraining and evaluating global chemistry climate models. Measurements include precursor and product gas species of reactive halogen compounds that impact ozone in the upper troposphere/lower stratosphere. High accuracy, in-situ measurements of ozone obtained during CONTRAST quantify ozone concentration profiles in the UT, where previous observations from balloon-borne ozonesondes were often near or below the limit of detection. CONTRAST was one of the three coordinated experiments to observe the TWP during January-February 2014. Together, CONTRAST, ATTREX and CAST, using complementary capabilities of the three aircraft platforms as well as ground-based instrumentation, provide a comprehensive quantification of the regional distribution and vertical structure of natural and pollutant trace gases in the TWP during NH winter, from the oceanic boundary to the lower stratosphere.
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Affiliation(s)
- L L Pan
- National Center for Atmospheric Research, Boulder, Colorado, USA
| | | | | | - S B Honomichl
- National Center for Atmospheric Research, Boulder, Colorado, USA
| | - J F Bresch
- National Center for Atmospheric Research, Boulder, Colorado, USA
| | - W J Randel
- National Center for Atmospheric Research, Boulder, Colorado, USA
| | - E C Apel
- National Center for Atmospheric Research, Boulder, Colorado, USA
| | - R S Hornbrook
- National Center for Atmospheric Research, Boulder, Colorado, USA
| | - A J Weinheimer
- National Center for Atmospheric Research, Boulder, Colorado, USA
| | - D C Anderson
- University of Maryland, College Park, Maryland, USA
| | | | - S Baidar
- University of Colorado Boulder, Boulder, Colorado, USA
| | - S P Beaton
- National Center for Atmospheric Research, Boulder, Colorado, USA
| | - T L Campos
- National Center for Atmospheric Research, Boulder, Colorado, USA
| | | | - D Chen
- Georgia Institute of Technology, Atlanta, Georgia, USA
| | - B Dix
- University of Colorado Boulder, Boulder, Colorado, USA
| | - V Donets
- University of Miami, Florida, USA
| | - S R Hall
- National Center for Atmospheric Research, Boulder, Colorado, USA
| | - T F Hanisco
- NASA Goddard Space Flight Center, Greenbelt, Maryland, USA
| | - C R Homeyer
- University of Oklahoma, Norman, Oklahoma, USA
| | - L G Huey
- Georgia Institute of Technology, Atlanta, Georgia, USA
| | - J B Jensen
- National Center for Atmospheric Research, Boulder, Colorado, USA
| | - L Kaser
- National Center for Atmospheric Research, Boulder, Colorado, USA
| | - D E Kinnison
- National Center for Atmospheric Research, Boulder, Colorado, USA
| | - T K Koenig
- University of Colorado Boulder, Boulder, Colorado, USA
| | - J-F Lamarque
- National Center for Atmospheric Research, Boulder, Colorado, USA
| | - C Liu
- Texas A&M University at Corpus Christi, Texas, USA
| | - J Luo
- National Center for Atmospheric Research, Boulder, Colorado, USA
| | - Z J Luo
- City College of New York, New York, New York, USA
| | - D D Montzka
- National Center for Atmospheric Research, Boulder, Colorado, USA
| | - J M Nicely
- University of Maryland, College Park, Maryland, USA
| | - R B Pierce
- NOAA Satellite and Information Service (NESDIS) Center for Satellite Applications and Research (STAR), Madison Wisconsin, USA
| | | | - T Robinson
- University of Hawaii at Mānoa, Hawaii, USA
| | - P Romashkin
- National Center for Atmospheric Research, Boulder, Colorado, USA
| | - A Saiz-Lopez
- Institute of Physical Chemistry Rocasolano, CSIC, Madrid, Spain
| | - S Schauffler
- National Center for Atmospheric Research, Boulder, Colorado, USA
| | - O Shieh
- University of Hawaii at Mānoa, Hawaii, USA
| | - M H Stell
- National Center for Atmospheric Research, Boulder, Colorado, USA
- Metropolitan State University, Denver, Colorado, USA
| | - K Ullmann
- National Center for Atmospheric Research, Boulder, Colorado, USA
| | - G Vaughan
- University of Manchester, Manchester, UK
| | - R Volkamer
- University of Colorado Boulder, Boulder, Colorado, USA
| | - G Wolfe
- NASA Goddard Space Flight Center, Greenbelt, Maryland, USA
- University of Maryland Baltimore County, Baltimore, Maryland, USA
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19
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Hall SR, Blundon HL, Ladda MA, Robertson AW, Martinez-Farina CF, Jakeman DL, Goralski KB. Jadomycin breast cancer cytotoxicity is mediated by a copper-dependent, reactive oxygen species-inducing mechanism. Pharmacol Res Perspect 2015; 3:e00110. [PMID: 25729577 PMCID: PMC4324684 DOI: 10.1002/prp2.110] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2014] [Accepted: 10/10/2014] [Indexed: 12/29/2022] Open
Abstract
Jadomycins are natural products biosynthesized by the bacteria Streptomyces venezuelae which kill drug-sensitive and multidrug-resistant breast cancer cells in culture. Currently, the mechanisms of jadomycin cytotoxicity are poorly understood; however, reactive oxygen species (ROS)–induced DNA cleavage is suggested based on bacterial plasmid DNA cleavage studies. The objective of this study was to determine if and how ROS contribute to jadomycin cytotoxicity in drug-sensitive MCF7 (MCF7-CON) and taxol-resistant MCF7 (MCF7-TXL) breast cancer cells. As determined using an intracellular, fluorescent, ROS-detecting probe, jadomycins B, S, SPhG, and F dose dependently increased intracellular ROS activity 2.5- to 5.9-fold. Cotreatment with the antioxidant N-acetyl cysteine lowered ROS concentrations to below baseline levels and decreased the corresponding cytotoxic potency of the four jadomycins 1.9- to 3.3-fold, confirming a ROS-mediated mechanism. Addition of CuSO4 enhanced, whereas addition of the Cu(II)-chelator d-penicillamine reduced, the ROS generation and cytotoxicity of each jadomycin. Specific inhibitors of the antioxidant enzymes, superoxide dismutase 1, glutathione S-transferase, and thioredoxin reductase, but not catalase, enhanced jadomycin-mediated ROS generation and anticancer activity. In conclusion, the results indicate that jadomycin cytotoxicity involves the generation of cytosolic superoxide via a Cu(II)-jadomycin reaction, a mechanism common to all jadomycins tested and observed in MCF7-CON and drug-resistant MCF7-TXL cells. The superoxide dismutase 1, glutathione, and peroxiredoxin/thioredoxin cellular antioxidant enzyme pathways scavenged intracellular ROS generated by jadomycin treatment. Blocking these antioxidant pathways could serve as a strategy to enhance jadomycin cytotoxic potency in drug-sensitive and multidrug-resistant breast cancers.
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Affiliation(s)
- Steven R Hall
- Department of Pharmacology, Faculty of Medicine, Dalhousie University Halifax, Nova Scotia, Canada, B3H 4R2
| | - Heather L Blundon
- College of Pharmacy, Faculty of Health Professions, Dalhousie University Halifax, Nova Scotia, Canada, B3H 4R2
| | - Matthew A Ladda
- College of Pharmacy, Faculty of Health Professions, Dalhousie University Halifax, Nova Scotia, Canada, B3H 4R2
| | - Andrew W Robertson
- Department of Chemistry, Faculty of Sciences, Dalhousie University Halifax, Nova Scotia, Canada, B3H 4R2
| | - Camilo F Martinez-Farina
- Department of Chemistry, Faculty of Sciences, Dalhousie University Halifax, Nova Scotia, Canada, B3H 4R2
| | - David L Jakeman
- College of Pharmacy, Faculty of Health Professions, Dalhousie University Halifax, Nova Scotia, Canada, B3H 4R2 ; Department of Chemistry, Faculty of Sciences, Dalhousie University Halifax, Nova Scotia, Canada, B3H 4R2
| | - Kerry B Goralski
- Department of Pharmacology, Faculty of Medicine, Dalhousie University Halifax, Nova Scotia, Canada, B3H 4R2 ; College of Pharmacy, Faculty of Health Professions, Dalhousie University Halifax, Nova Scotia, Canada, B3H 4R2
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Cáceres CE, Davis G, Duple S, Hall SR, Koss A, Lee P, Rapti Z. Complex Daphnia interactions with parasites and competitors. Math Biosci 2014; 258:148-61. [PMID: 25445737 DOI: 10.1016/j.mbs.2014.10.002] [Citation(s) in RCA: 12] [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: 11/08/2013] [Revised: 10/01/2014] [Accepted: 10/07/2014] [Indexed: 10/24/2022]
Abstract
Species interactions can strongly influence the size and dynamics of epidemics in populations of focal hosts. The "dilution effect" provides a particularly interesting type of interaction from a biological standpoint. Diluters - other host species which resist infection but remove environmentally-distributed propagules of parasites (spores) - should reduce disease prevalence in focal hosts. However, diluters and focal hosts may compete for shared resources. This combination of positive (dilution) and negative (competition) effects could greatly complicate, even undermine, the benefits of dilution and diluter species from the perspective of the focal host. Motivated by an example from the plankton (i.e., zooplankton hosts, a fungal parasite, and algal resources), we study a model of dilution and competition. Our model reveals a suite of five results: • A diluter that is a superior competitor wipes out the host, regardless of parasitism. Although expected, this outcome is an ever-present danger in strategies that might use diluters to control disease. • If the diluter is an inferior competitor, it can reduce disease prevalence, despite the competition, as parameterized in our model. However, competition may also reduce density of susceptible hosts to levels below that seen in focal host-parasite systems alone. • As they decrease disease prevalence, diluters destabilize dynamics of the focal host and their resources. Thus, diluters undermine the stabilizing effects of disease. • The four species combination can generate very complex dynamics, including period-doubling bifurcations and torus (Neimark-Sacker) bifurcations. • At lower resource carrying capacity, the diluter’s dilution of spores is 'helpful' to the focal host, i.e., dilution can elevate host density by reducing disease. But, as the resource carrying capacity increases further, the equilibrium density of the diluter increases while the density of the focal host decreases, despite competition. Namely, the negative effects of competition start to outweigh the positive effects of dilution from the perspective of equilibrium density of the focal host.
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Affiliation(s)
- C E Cáceres
- School of Integrative Biology, University of Illinois at Urbana-Champaign, Urbana, IL 61801, United States
| | - G Davis
- Department of Mathematics, University of Illinois at Urbana-Champaign, Urbana, IL 61801, United States
| | - S Duple
- School of Integrative Biology, University of Illinois at Urbana-Champaign, Urbana, IL 61801, United States
| | - S R Hall
- Department of Biology, Indiana University, Bloomington, IN 47405, United States
| | - A Koss
- Department of Mathematics, University of Illinois at Urbana-Champaign, Urbana, IL 61801, United States
| | - P Lee
- School of Integrative Biology, University of Illinois at Urbana-Champaign, Urbana, IL 61801, United States
| | - Z Rapti
- Department of Mathematics, University of Illinois at Urbana-Champaign, Urbana, IL 61801, United States.
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21
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Affiliation(s)
- S R Hall
- School of Chemistry, University of Bristol, Bristol BS8 1TS, UK
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22
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Auld SKJR, Penczykowski RM, Housley Ochs J, Grippi DC, Hall SR, Duffy MA. Variation in costs of parasite resistance among natural host populations. J Evol Biol 2013; 26:2479-86. [PMID: 24118613 DOI: 10.1111/jeb.12243] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.8] [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: 06/19/2013] [Revised: 08/09/2013] [Accepted: 08/09/2013] [Indexed: 11/30/2022]
Abstract
Organisms that can resist parasitic infection often have lower fitness in the absence of parasites. These costs of resistance can mediate host evolution during parasite epidemics. For example, large epidemics will select for increased host resistance. In contrast, small epidemics (or no disease) can select for increased host susceptibility when costly resistance allows more susceptible hosts to outcompete their resistant counterparts. Despite their importance for evolution in host populations, costs of resistance (which are also known as resistance trade-offs) have mainly been examined in laboratory-based host-parasite systems. Very few examples come from field-collected hosts. Furthermore, little is known about how resistance trade-offs vary across natural populations. We addressed these gaps using the freshwater crustacean Daphnia dentifera and its natural yeast parasite, Metschnikowia bicuspidata. We found a cost of resistance in two of the five populations we studied - those with the most genetic variation in resistance and the smallest epidemics in the previous year. However, yeast epidemics in the current year did not alter slopes of these trade-offs before and after epidemics. In contrast, the no-cost populations showed little variation in resistance, possibly because large yeast epidemics eroded that variation in the previous year. Consequently, our results demonstrate variation in costs of resistance in wild host populations. This variation has important implications for host evolution during epidemics in nature.
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Affiliation(s)
- S K J R Auld
- School of Natural Sciences, University of Stirling, Stirling, UK; School of Biology, Georgia Institute of Technology, Atlanta, GA, USA
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23
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Kinkaid H, Yarr J, Hall SR, McCusker G, McStay M, Briggs GM. Can touch imprint cytology replace fine needle aspiration within current clinical practice? Breast Cancer Res 2010. [PMCID: PMC2978831 DOI: 10.1186/bcr2667] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
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Abstract
Parasites are integral parts of most ecosystems, yet attention has only recently focused on how community structure and abiotic factors impact host-parasite interactions. In lakes, both factors are influenced by habitat morphology. To investigate the role of habitat structure in mediating parasitism in the plankton, we quantified timing and prevalence of a common microparasite (Metschnikowia bicuspidata) in its host, Daphnia dentifera, in 18 lakes that vary in basin size and shape. Over three years, we found substantial spatial and temporal variation in the severity of epidemics. Although infection rates reached as high as 50% in some lakes, they did not occur in most lakes in most years. Host density, often considered to be a key determinant of disease spread, did not explain a significant amount of variation in the occurrence of epidemics. Furthermore, host resistance does not fully explain this parasite's distribution, since we easily infected hosts in the laboratory. Rather, basin shape predicted epidemics well; epidemics occurred only in lakes with steep-sided basins. In these lakes, the magnitude of epidemics varied with year. We suggest that biological (predation) and physical (turbulence) effects of basin shape interact with annual weather patterns to determine the regional distribution of this parasite.
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Affiliation(s)
- C E Cáceres
- School of Integrative Biology, University of Illinois at Urbana-Champaign, 61801, USA.
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26
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Abstract
In addition to macromolecular interactions that provide co-stimulation during antigen-presenting cell (APC) and CD4+ T-cell conjugation, covalent chemical events between specialized ligands have been implicated in T-cell co-stimulation. These take the form of transient Schiff base formation between carbonyls and amines expressed on APC and T-cell surfaces. Small Schiff base-forming molecules, such as tucaresol, can substitute for the physiological donor of carbonyl groups and provide co-stimulation to T cells, thereby functioning as orally active immunopotentiatory drugs. The Schiff base co-stimulatory pathway in T cells has been partially characterized in terms of changes in Na+ and K+ transport, and activation of the mitogen activated protein kinase (MAPK) ERK2. In the present study, the effects of Schiff base co-stimulation by tucaresol on the T-cell receptor (TCR)-dependent pathway leading to Ca2+ release were investigated. Schiff base co-stimulation by tucaresol was found to prime for enhanced TCR-dependent phospholipase C-gamma phosphorylation, inositol 1,4,5-triphosphate production, and Ca2+ mobilization that correlated with functional enhancement of interleukin-2 production in primary T cells. The effects on Ca2+ occurred comparably in Jurkat and primary CD4+ T cells responding to anti-CD3 monoclonal antibody. Enhancement of the Ca2+ response required a 10-min priming period and was prevented by prior covalent ligation of cell-surface free amino groups by sulpho-N-hydroxy succinimido-biotin; clofilium-mediated inhibition of tucaresol-induced changes in intracellular K+; and selective inhibition of the MAPK pathway. The data are consistent with a priming mechanism in which late co-stimulation-triggered events exert a positive influence on early TCR-triggered events. In additional studies of murine T cells expressing trans-gene TCRs, tucaresol was likewise shown to prime for enhanced Ca2+ mobilization in response to physiological TCR-engagement by MHC-peptide complexes.
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Affiliation(s)
- S R Hall
- Department of Immunology and Virology, GlaxoSmithKline Research and Development, Medicines Research Centre, Stevenage, UK.
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Milne B, Hall SR, Sullivan ME, Loomis C. The release of spinal prostaglandin E2 and the effect of nitric oxide synthetase inhibition during strychnine-induced allodynia. Anesth Analg 2001; 93:728-33. [PMID: 11524348 DOI: 10.1097/00000539-200109000-00037] [Citation(s) in RCA: 12] [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: 11/26/2022]
Abstract
The removal of spinal glycinergic inhibition by intrathecal strychnine produces an allodynia-like state in rodents. Our objective was to measure spinal prostaglandin E2 (PGE2) release during strychnine-allodynia and examine the effects of Nomega-nitro-L-arginine (L-NOARG), an inhibitor of nitric oxide synthetase. Under halothane, rats were fitted with intrathecal and spinal microdialysis catheters, and microelectrodes implanted into the locus coeruleus for measurement of catechol oxidation current (CAOC) using voltammetry. Animals were then administered urethane and treated as follows: 1) baseline control 10 min, intrathecal strychnine (40 microg) 10 min, 10 min of hair deflection, and 2) 10-min control followed by intrathecal strychnine (40 microg) with hair deflection for 60 min. Spinal dialysate samples were collected for PGE2 levels determined by using immunoassay. In separate experiments, the effect of intrathecal strychnine (40 microg) followed by hair deflection was studied in rats pretreated with intrathecal l-NOARG (50 nmol). After intrathecal strychnine, hair deflection significantly increased spinal PGE2 release (619% +/- 143%), locus coeruleus CAOC (181% +/- 6%), and mean arterial pressure (123% +/- 2%) P < 0.05. Pretreatment with intrathecal l-NOARG significantly inhibited strychnine-allodynia. In this model, hair deflection evokes spinal PGE2 release, locus coeruleus activation, and an increase in mean arterial pressure. L-NOARG pretreatment attenuated the locus coeruleus CAOC, a biochemical index of strychnine-allodynia, suggesting a mediator role of nitric oxide. A mediator role of nitric oxide is also implicated, helping to explain the pathophysiology of this allodynic pain.
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Affiliation(s)
- B Milne
- Department of Anesthesiology, Pharmacology, and Toxicology, Queen's University, Kingston, Ontario, Canada
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Abstract
The STAR File (J. Chem. Inf Comput. Sci. 1994, 34, 505-508) is used widely in structural chemistry for exchanging numerical and text information with scientific journals and databases. These exchanges are increasingly dependent on data dictionaries to facilitate automatic data validation and checking. Definitions in data dictionaries are constructed using attribute descriptors, and this paper describes a method attribute for specifying the relationships between data items as an executable script written in a new relational expression language called dREL. The addition of this attribute improves the precision and the semantic content of dictionaries by providing relational representations of data, as well as facilitating the direct evaluation of derivable data items. The capacity to evaluate derivative data directly from the combination of primitive data and dictionary expressions is expected to change future archival approaches. The design concepts of the relational expression language dREL parser, which are applicable to any discipline, are described.
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Affiliation(s)
- N Spadaccini
- Department of Computer Science and Crystallography Centre, University of Western Australia, Nedlands, Perth, Australia.
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Abstract
Previous studies have shown that activation of N-methyl-D-aspartate (NMDA) receptors and formation of nitric oxide (NO) contributes to the hyperactivity of locus coeruleus (LC) noradrenergic neurons and behavioural symptoms seen during opioid withdrawal. However, the role of soluble guanylyl cyclase (sGC), the 'physiological' target of NO, in this phenomenon is unclear. In this study, the effect of 1H-[1,2,4]oxadiazolo[4,3-a]quinoxalin-1-one (ODQ), a highly selective sGC inhibitor, on the naloxone-precipitated morphine withdrawal was examined using differential normal pulse voltammetry (DNPV) to measure LC activity, in vivo microdialysis to measure glutamate/aspartate release response, and behavioural assessment to evaluate withdrawal symptoms. In halothane-anaesthetized rats, acute intracerebroventricular (i.c.v.) morphine (10 microg) reduced the catecholamine oxidation current (CA.OC) (54.5+/-4.9% of baseline). Naloxone (2 mg/kg, i.v.) reversed this action of morphine and produced a rebound increase in CA.OC (136.1+/-6.0% of baseline), representing acute morphine withdrawal. Administration of ODQ (200 nmol, i.c.v.) blocked this response without affecting acute morphine action. In animals chronically treated with morphine (15 microg/microl/h, i.c.v., 5 days), naloxone significantly increased both the CA.OC signal (270.0+/-19.6% of baseline) and the release of L-glu (193+/-30.4%) and L-asp (221.5+/-28.4%) above baseline. These responses were attenuated in animals pretreated with ODQ. In unanaesthetized chronic morphine dependent rats, ODQ treatment suppressed the signs of withdrawal precipitated by naloxone (10 mg/kg). Taken together, the results of this study suggest that sGC plays an intermediary role in the genesis of LC neuronal hyperactivity and behavioural signs of morphine withdrawal.
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Affiliation(s)
- M E Sullivan
- Department of Pharmacology and Toxicology and Anesthesiology, Faculty of Health Sciences, Queen's University, Kingston, Ontario, Canada
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Abstract
Peripheral CD4+ T cells can be divided into two different functional populations based on the expression of distinct isoforms of the surface molecule CD45. We have investigated the differences in the proximal signaling induced by anti-CD3 monoclonal antibody in purified populations of "naive" CD45RA+ and "memory" CD45RO+ human CD4+ T cells. Expression of cell surface CD3, CD4 and CD28 was comparable between RA+ and RO+ cells. However, TCR-directed stimulation in the form of anti-CD3 produced markedly different patterns of intracellular signaling. Greater inositol triphosphate generation occurred in naive cells and the rise in intracellular free calcium was also substantially greater in naive than in memory cells. Cells with the naive phenotype were considerably more active in TCR-dependent tyrosine phosphorylation, both at an overall level and specifically in terms of TCR-zeta and ZAP-70 phosphorylation. Despite these differences in phosphorylation, the amounts of TCR-zeta, ZAP-70 and Ick were equivalent between the two subsets. These findings suggest that the TCR-dependent signaling is differentially regulated in naive and memory CD4+ T cells. This may be due to differences in the way that the two isoforms of the CD45 phosphatase regulate the activity of proximal kinases in the TCR signaling pathway, and could be an important means by which the unique functions of differentiated T cell populations are maintained.
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Affiliation(s)
- S R Hall
- Immunology Unit, Glaxo Wellcome Research and Development, Medicines Research Centre, Stevenage, GB.
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Hall SR, Wang L, Milne B, Loomis C. Activation of the rostral ventrolateral medulla in an acute anesthetized rodent strychnine model of allodynia. Anesth Analg 1999; 88:1125-30. [PMID: 10320182 DOI: 10.1097/00000539-199905000-00030] [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] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
UNLABELLED After the administration of intrathecal strychnine, allodynia is manifested as activation of supraspinal sites involved in pain processing and enhancement of cardiovascular responses evoked by normally innocuous stimuli. The objective of this study was to investigate the effect of strychnine-induced allodynia on adrenergic neuronal activity in the C1 area of the rostral ventrolateral medulla (RVLM), a major site involved in cardiovascular regulation. The effect of intrathecal strychnine (40 microg) or saline followed by repeated hair deflection to caudal lumbar dermatomes in the urethane-anesthetized rat was assessed by measuring voltammetric changes in the RVLM catechol oxidation current (CA x OC), mean arterial pressure (MAP), and heart rate (HR). After the administration of intrathecal strychnine, hair deflection evoked a significant and sustained increase in the RVLM CA x OC and MAP (peak 146.4%+/-5.6% and 159%+/-18.4% of baseline, respectively; P < 0.05). There was a nonsignificant increase in HR (peak 128%+/-8.2%). In the absence of hair deflection, there was no demonstrable change. Intrathecal saline-treated rats failed to demonstrate changes in RVLM CA x OC, MAP, or HR. In the present study, we demonstrated that, after the administration of intrathecal strychnine, innocuous hair deflection evokes temporally related neuronal activation in the rat RVLM and an increase in MAP. This suggests that the RVLM mediates, at least in part, the cardiovascular responses during strychnine allodynia. IMPLICATIONS Neural injury-associated pain, as manifested by allodynia, is resistant to conventional treatment. In a rat model of allodynia, we demonstrated activation of the brain region involved in sympathetic control. Innovative therapies that target this region may be successful in managing this debilitating condition.
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Affiliation(s)
- S R Hall
- Department of Anaesthesia, Queens University, Kingston, Ontario, Canada
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Hall SR, Milne B, Loomis C. Spinal action of ketorolac, S(+)- and R(-)-ibuprofen on non-noxious activation of the catechol oxidation in the rat locus coeruleus: evidence for a central role of prostaglandins in the strychnine model of allodynia. Anesthesiology 1999; 90:165-73. [PMID: 9915325 DOI: 10.1097/00000542-199901000-00022] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [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: 11/26/2022]
Abstract
BACKGROUND Blockade of spinal glycine receptors with intrathecal strychnine produces an allodynia-like state in the anesthetized rat. Innocuous hair deflection in the presence of intrathecal strychnine induces a nociceptive-like activation of catechol oxidation in the locus coeruleus and enhances cardiovascular responses. Because prostaglandins play a central role in augmenting pain, this study evaluated the effect of intrathecal nonsteroidal antiinflammatory drugs in strychnine-induced allodynia. METHODS In urethane-anesthetized rats, changes in catechol oxidation in the locus coeruleus, measured using in vivo voltammetry, and cardiovascular parameters evoked by hair deflection of caudal dermatomes were determined after strychnine (40 microg) or saline were administered intrathecally. Subsequently, the effects of 30 microg ketorolac, 10 microg S(+)-ibuprofen, and 10 microg R(-)-ibuprofen administered intrathecally were evaluated. RESULTS After strychnine was administered intrathecally, hair deflection evoked an increase in the locus coeruleus catechol oxidation (peak, 149.7+/-7.2% of baseline) and mean arterial blood pressure (peak, 127.5+/-3.8% of baseline). These responses were not observed after saline was administered intrathecally. All hair deflection-evoked, strychnine-dependent peak responses were attenuated significantly with intrathecally administered ketorolac and S(+)-ibuprofen but not with R(-)-ibuprofen. CONCLUSIONS Locus coeruleus catechol oxidation is a sensitive biochemical index of strychnine-induced allodynia and is correlated temporally with the cardiovascular responses evoked by hair deflection during spinal glycinergic inhibition. The ability of intrathecally administered ketorolac and S(+)-ibuprofen, but not R(-)-ibuprofen, to suppress the locus coeruleus catechol oxidation and cardiovascular peak responses evoked during strychnine-induced allodynia provide evidence that central prostaglandins play an important role in the abnormal sensory processing of strychnine-induced allodynia.
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Affiliation(s)
- S R Hall
- Department of Anaesthesia, Queen's University, Kingston, Ontario, Canada
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33
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Hall SR. Implant diagnostics utilizing computed tomography imaging. J Okla Dent Assoc 1998; 85:19-24. [PMID: 9526233] [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: 02/06/2023]
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34
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Abstract
The greater Dayton area has begun building the nation's first advanced technology community network for sharing patient medical information among independent hospitals. Its success in doing so has resulted from the surmounting of numerous business and technical barriers. Others planning to develop such networks can learn from the Dayton experience.
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Affiliation(s)
- T W Ferratt
- Department of MIS & Decision Sciences, School of Business Administration, University of Dayton, OH, USA
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Hall SR. The community-centered board model of managed care for people with developmental disabilities. Health Soc Work 1996; 21:225-229. [PMID: 8854127 DOI: 10.1093/hsw/21.3.225] [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] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Affiliation(s)
- S R Hall
- Resource Exchange, Colorado Springs, CO 80909, USA
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36
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Hall SR, Campbell LE, Meek DW. Phosphorylation of p53 at the casein kinase II site selectively regulates p53-dependent transcriptional repression but not transactivation. Nucleic Acids Res 1996; 24:1119-26. [PMID: 8604347 PMCID: PMC145737 DOI: 10.1093/nar/24.6.1119] [Citation(s) in RCA: 57] [Impact Index Per Article: 2.0] [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 p53 tumour suppressor protein is a potent transcription factor which plays a central role in the defence of cells against DNA damage and the propagation of malignant clones. We have previously shown that phosphorylation of serine 386 in mouse p53 by the growth- associated protein kinase, casein kinase II (CKII), plays an important role in the ability of p53 to block the proliferation of drug-resistant colonies. In this paper we show that blocking phosphorylation of serine 386 through an alanine substitution, or placing a constitutive negative charge at this position in the form of aspartate, had no significant influence on p53-dependent transcriptional activation of a promoter containing 13 copies of a p53 consensus binding sequence, or of the p21WAF1 promoter which is a natural target for p53. In contrast, the alanine mutant showed a weak reduction in the ability of p53 to repress expression from the c-fos promoter, which is a target for p53-dependent repression in vivo. Strikingly, when the repression of the SV40 early promoter was examined, a reduction in the repression capacity of up to 5-fold was observed. Moreover, repression of the SV40 promoter could be partially restored by aspartic acid substitution at the phosphorylation site. These data indicate that phosphorylation at a specific C-terminal site can selectively regulate p53-dependent repression, but not transactivation.
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Affiliation(s)
- S R Hall
- Biomedical Research Centre, University of Dundee, United Kingdom
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37
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Abstract
The aim of the present study was to provide preliminary information on the acute and chronic effects of infectious mononucleosis (IM) on memory, attention, psychomotor performance and mood. These issues were examined by comparing individuals with acute IM, those who had the initial illness some months before, and matched healthy controls. Objective measures of memory, attention, motor skills and visual functions were obtained, as were subjective reports of mood. The results showed selective effects of acute IM on performance and mood, with the profile of impairments being very similar to those observed in previous studies of influenza. Different impairments were observed in subjects who had the primary illness several months before, and the effects observed in this group were similar to those observed in recent studies of chronic fatigue syndrome patients. Both acute and chronic IM subjects reported similar levels of symptoms and psychopathology, with both groups having greater scores than the controls. However, the performance impairments did not reflect symptoms or psychopathology. One may conclude that the study of IM will provide important data on both the acute and longer lasting effects of viral infections on the brain and behaviour.
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Affiliation(s)
- S R Hall
- School of Psychology, University of Birmingham, UK
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Michael LH, Entman ML, Hartley CJ, Youker KA, Zhu J, Hall SR, Hawkins HK, Berens K, Ballantyne CM. Myocardial ischemia and reperfusion: a murine model. Am J Physiol 1995; 269:H2147-54. [PMID: 8594926 DOI: 10.1152/ajpheart.1995.269.6.h2147] [Citation(s) in RCA: 189] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Myocardial ischemia followed by reperfusion promotes a complex series of inflammatory reactions as noted in a variety of large animal studies. With development of genetically altered mice, there is intense interest in developing murine models to study mechanisms operative in cardiovascular disease. We developed a mouse model to study coronary artery occlusion and reperfusion effects and the method required to perform these studies both acutely and chronically. In mice, we applied a left anterior descending coronary artery occlusion either permanently or for 30 or 60 min followed by reperfusion allowing flow through the previously occluded coronary artery bed. Reperfusion was documented visually as well as by using Doppler ultrasound and histopathological techniques. The area at risk (AAR) and infarct size (IS) were assessed by EVans blue dye and triphenyltetrazolium chloride staining with computerized planimetry using an image analysis software program. The infarct as percentage of AAR and IS as percentage of the left ventricle in 13 mice with permanent occlusion was 68.6 +/- 4.4 and 28.0 +/- 2.8%, respectively. Reperfusion after occlusions of 60 and 30 min resulted in a significant decrease in IS as a percentage of the AAR compared with permanent occlusion. Histological examination of the ischemic and reperfused myocardium shows infiltration of leukocytes into the ischemic region as well as contraction bands classically associated with reperfusion. This new model allows assessment of AAR, IS, cardiac function, and pathophysiology in the mouse. With the current technology to develop genetically altered mice for overexpression or targeted mutations of various genes, this model is used to understand the complex pathophysiology of ischemia and reperfusion injury.
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Affiliation(s)
- L H Michael
- Sections of Cardiovascular Sciences, Department of Medicine and Pediatrics, Methodist Hospital, Houston, USA
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39
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Rhodes J, Chen H, Hall SR, Beesley JE, Jenkins DC, Collins P, Zheng B. Therapeutic potentiation of the immune system by costimulatory Schiff-base-forming drugs. Nature 1995; 377:71-5. [PMID: 7659167 DOI: 10.1038/377071a0] [Citation(s) in RCA: 113] [Impact Index Per Article: 3.9] [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]
Abstract
Immune responses are orchestrated by CD4 T lymphocytes, which receive a cognitive signal when clonally distributed receptors are occupied by major histocompatibility complex (MHC) class II-bound peptides on antigen-presenting cells (APCs). The APCs provide costimulatory signals, through macromolecules such as CD80, that regulate outcomes in terms of T-cell activation or anergy. We have studied essential complementary chemical events in the form of Schiff base formation between carbonyls and amines that are constitutively expressed on presenting cell and T-cell surfaces and provide a new target for manipulation of immune responses. Here we show that small Schiff base-forming molecules can substitute for the physiological donor of carbonyl groups and provide a costimulatory signal to CD4 Th-cells through a mechanism that activates clofilium-sensitive K+ and Na+ transport. One such molecule, tucaresol, enhances CD4 Th-cell responses, selectively favouring a Th1-type profile of cytokine production. In vivo tucaresol potently enhances CD4 Th-cell priming and CD8 cytotoxic T-cell priming to viral antigens, and has substantial therapeutic activity in murine models of disease.
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Affiliation(s)
- J Rhodes
- Molecular Immunology Group, Wellcome Research Laboratories, Beckenham, Kent, UK
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40
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Beesley JE, Hall SR, Page MJ, Affleck K. Early elemental and ionic changes in cultured cells after stimulation with epidermal growth factor. Scanning Microsc 1995; 9:231-238. [PMID: 8553019] [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: 05/22/2023]
Abstract
Stimulation of A431 cells (a human vulval epidermal cell line) with 50 ng/ml of epidermal growth factor (EGF) in the presence of 1.7 mM extracellular calcium produced a sharp and sustained rise in intracellular ionic Ca2+, increased elemental Na, decreased K and a rise in Ca. In the absence of extracellular calcium, the initial Ca2+ rise remained but the sustained elevation of intracellular Ca2+ was abolished, Na and K fluxes were variable and the Ca did not change. Increased Na and decreased K was marked at 2 minutes and returned to the control value after 60 minutes. The increase in Ca was an early event. Cells stimulated with EGF showed a pronounced morphological disruption, especially the mitochondria. The response of NR6/SA3 and NR6/DC7 cells (genetically engineered rodent fibroblast cell lines) to EGF stimulation was higher than that of the A431 cells, as was the resting cytoplasmic Ca2+. Untreated NR6/SA3 and NR6/DC7 cells possessed an increased Na/K ratio when compared with A431 cells.
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Affiliation(s)
- J E Beesley
- Wellcome Research Laboratories, Beckenham, Kent, U.K
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41
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Beesley JE, Foxwell N, Hall SR. X-ray microanalysis and single cell microfluorimetry for microscopical investigation of cellular reactions to pharmacological agents. Cell Biol Int 1993; 17:703. [PMID: 8374605 DOI: 10.1006/cbir.1993.1127] [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] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Affiliation(s)
- J E Beesley
- Department of Pharmacology, Wellcome Research Laboratories, Beckenham, Kent, UK
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42
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Stewart JM, Collins DM, Watenpaugh KD, Prince E, Hall SR. Programs for phasing by entropy maximization as implemented in Xtal3.2: a crystallographic software system. Acta Cryst D 1993; 49:100-6; discussion 107. [PMID: 15299550 DOI: 10.1107/s0907444992008898] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Xtal3.2, a crystallographic software package, is an international development project involving about 40 researchers over a full spectrum of crystallographic interests. This development has been supported by many national and international agencies and commercial institutions since the first version in 1983. The 1992 release, Xtal3.2, contains software for 95 different calculations. These range from the processing of raw diffraction data to interactive molecular graphics, atomic charge estimation, electronic publication preparation, and the structure solution and refinement of small and large molecules. Tests of the Xtal programs for phase determination and phase refinement by the application of 'maximum entropy' are presented.
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Affiliation(s)
- J M Stewart
- University of Maryland, College Park 20742, USA
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43
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Hall SR, Sigee DC, Beesley JE. Scanning X-ray microanalysis of microcarrier cultured endothelial cells: elemental changes during the transition to confluency and the effect of ionophore A23187. Scanning Microsc 1992; 6:753-62; discussion 763. [PMID: 1439667] [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: 12/27/2022]
Abstract
Porcine endothelial cells were grown on microcarrier beads and examined by scanning electron microscopy (SEM) at various times after initiation of culture. Total cell coverage on the bead surface varied from mean values of approximately 7% (3h) to 80% (96h). Beam penetration into the subcellular matrix presents a major problem with SEM X-ray microanalysis of microcarrier cultured cells and necessitates the use of an accelerating voltage not exceeding 10kV. At this voltage and below, X-ray contribution from elements present in the microcarrier bead has minimal effect on the determination of cell elemental levels. Washing the cells with 0.15M sucrose was the least perturbing of the rinsing techniques investigated, removing surface culture medium but not internal diffusible ions. X-ray microanalysis revealed detectable levels of Na, P, S, Cl, K and Ca in the cells, with well-marked changes from initial attachment to confluency. The level of K decreased from approximately 1.0% at 3h to 0.4% at 24h, with a corresponding decrease in the K/Na ratio. This unexpectedly low level of K was invariably observed after 24h, and is a genuine feature of established microcarrier culture. The effect of ionophore A23187 was determined at the 3h culture stage, and resulted in significant increases in the concentration of divalent cations (Mg2+, Ca2+), monovalent ions (Na+, Cl-) and a decrease in the level of K+.
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Affiliation(s)
- S R Hall
- Dept. Cell and Structural Biology, University of Manchester, U.K
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44
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Smith AP, Rusted JM, Savory M, Eaton-Williams P, Hall SR. The effects of caffeine, impulsivity and time of day on performance, mood and cardiovascular function. J Psychopharmacol 1991; 5:120-8. [PMID: 22282363 DOI: 10.1177/026988119100500205] [Citation(s) in RCA: 43] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Two experiments were carried out to examine the effects of caffeine on performance, mood and cardiovascular function. The results showed that the effects of caffeine depended on the dose, time of administration, the function being examined and the impulsivity of the subject. Changes in blood pressure were only observed when a high dose (3 mg/kg) was used. The effects of this dose on performance depended on the impulsivity of the subject, with high impulsives performing worse in the de-caffeinated condition but getting a greater benefit from the caffeine. The high dose of caffeine also removed the post-lunch dip in sustained attention. The second experiment, which used a lower dose of caffeine (~60 mg), failed to demonstrate any caffeine x impulsivity or caffeine x time of day effects on performance. However, caffeine improved performance on a logical reasoning task and caffeine x time of day x impulsivity effects were found in analyses of visual search tasks. The mood data also support the view that the effects of caffeine depend on a combination of factors similar to those outlined for performance.
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Affiliation(s)
- A P Smith
- School of Psychology, University of Wales College of Cardiff, Cardiff CF1 3YG
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45
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Castleden IR, Hall SR, Nimgirawath S, Thadaniti S, White AH. The Flavonoids of Combretum quadrangulare: Crystal structures of the Polymorphic Forms of 5-Hydroxy-2-(4'-hydroxy-3',5'-dimethoxyphenyl)-3,7-dimethoxy-4H-1-benzopyran-4-one. Aust J Chem 1985. [DOI: 10.1071/ch9851177] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
The following substituted 2-phenyl-4H-1-benzopyran-4-ones have been isolated from the dried flowers of Combretum quadrangulare Kurz ( Combretaceae ): 5-hydroxy-3,3′,4′,5′,7-pentamethoxy ( combretol ) (1),
3′,5-dihydroxy-3,4′,7-trimethoxy ( ayanin ) (2) and 4′,5-dihydroxy- 3,3′,5′,7-tetramethoxy (3). The last substance (3) was obtained as a mixture of two polymorphic forms (α and β) each of which was characterized by X-ray diffraction. Diffractometer data at 295 K were refined by full matrix least squares to residuals of 0.043 (1181 'observed' reflections) for the α-phase and 0.044 (1421) for the β phase of (3). Crystals of the α-phase of (3) are triclinic, Pī, a 12.663(6), b 9.592(4), c 7.444(4) Ǻ, α 102.48(3), β 101.39(4),
γ 91.72(4)°,Z 2. Crystals of the β-phase of (3) are monoclinic P21/n, a 17.139(8), b 12.728(6), c 7.845(7) Ǻ, β 95.07(6)°, Z 4. An unambiguous synthesis of (3) was also achieved.
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46
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Abstract
.A new, metastable phase of lepidopterene, (5,6,11,12-tetrahydro-4b,12[1',2']:6,10b[1",2"]-dibenzenochrysene) (1), has been obtained from methylene chloride solution, exhibiting a luminescence
which differs from that of the stable form, having an absorption maximum at 580 nm rather than
560 nm. Single crystal X-ray diffraction determination of the structure of the new phase shows
it to be orthorhombic, Pbcn, a 36.75(3), b 7.229(7), c 44.85(3) Ǻ, Z 24, the structure being refined
to a residual of 0.065 for 2413 independent 'observed' reflections. Despite the relatively low precision
of the determination, it is evident that in the metastable form, the gross molecular disposition is
severely distorted. The crystal structure of dimethyllepidopterene (2) has also been determined,
and refined by least squares to a residual of 0.041 for 632 'observed' reflections. Crystals are mono-
clinic, P21/c, with a 9.607(4), b 11.564(7), c 10.576(6) Ǻ, β 107.72(4), Z 2; the molecules are
centrosymmetric.
Tetrachlorolepidopterene (31, formed by the dimerization of 1,5-dichloro-9-anthrylmethyl,
yields two crystalline forms from xylene and methylene chloride solutions which differ in their
crystal exciplex luminescence, showing emission maxima at 590 and 575 nrn respectively. Single-
crystal X-ray structure determination confirms that the two crystalline forms, α- and β-, are polymorphs of the same centrosymmetric molecular species. For the α-form, crystals are triclinic, P1 ,
a 15.374(6), b 9.858(4), c 8.000(4) Ǻ, α 83.98(4), β 83.73(3), γ 71.53(3)°, Z 2, 2138 independent
'observed' reflections being refined to a residual of 0.037; the unit cell contains two independent
centrosymmetric molecules. For the β-form, crystals are monoclinic, C2/c, a 11.03(2), b 13.67(2),
c 16.32(3) Ǻ, β 1 1 1.13(12)°, Z 4; the residual for 1554 independent reflections was 0.053.
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Abstract
The crystal structure of
8-hydroxy-1H-naphtho[2,1,8-mna]xanthen-1-one, C19H10O3,
obtained as an indefinite methanolsolvate, has been
determined at 295K by single-crystal X-ray diffraction methods, being refined
by full matrix least squares to a residual of 0.056 for 892 independent 'observed'
reflections. Crystals are monoclinic, P21/c, a 5.128(4), b 10.024(9), c 27.45(2) �, β 107.73(6)�, Z 4.
The packing of the molecules is typically that of charge-transfer complexes, with
an interplanar spacing of c.3.5 �.
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48
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Abstract
(Z)-7-t-Butyl-5
methoxy-3-[(Z)-2?-methoxy-5,5'-dimethyl-4'-oxohex-2'-enylidene]benzofuran-2(3H)-one
has been found to undergo Diels-Alder dimerization in which the exocyclic
double bond adds to the s-cis diene
moiety. The stereochemistry of the Diels-Alder dimer was established by a
single-crystal X-ray structure determination. Crystals of the dimer, C44H56O10,
are monoclinic, P21/n, a 12.23(1),
b 19.43(2), c 18.71(2) �, β 107.76(7)�, Z 4; a residual of 0.046 was
obtained for the 2519 'observed' reflections. In the dimer, two benzofuranone moieties are situated so as to be vicinal spiro substituents of the cyclohexene
formed in the Diels-Alder addition. The bond between the two benzofuranone units is unusually long [1.597(6)�]. The
shielding of one aromatic hydrogen in the n.m.r. spectrum of the dimer results
from the disposition of the two aromatic systems.
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49
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Hall SR, Skelton BW, White AH. Structural studies in the ruthenium(II)/(±)-ortho-Phenylenebis{methyl(phenyl)-phosphine/arsine) system. II. Crystal structure of trans-Dichloro[(±)-ortho-phenylenebis{methyl(phenyl)-phosphine}][(±)-ortho-phenylenebis(methyl(pheny1)-phosphine) P-oxide]ruthenium(II). Aust J Chem 1983. [DOI: 10.1071/ch9830267] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
The crystal and molecular
structure of the title complex, trans-[RuCl2{(�)-o-C5H4(PMePh)2}{(�)- o-C5H4(PMePh)(P(O)MePh)}], has been established by a single-crystal X-ray
diffraction study at 295(1) K, being refined to a residual of 0.037 for 2669
independent 'observed' reflections. Crystals are orthorhombic, P212121,
a 16.655(5), b 15.805(4), c 14.823(8)
�, Z 4. The chlorine atoms lie trans
to each other in the coordination sphere of the six-coordinate ruthenium, with
the O-C6H4(PMePh)2
and o-C6H4(PMePh)(P(O)MePh) ligands being P,P? and O,P' bidentate respectively.
The ruthenium-chlorine distances are 2.434(2) and 2.425(2) �; the two mutually trans ruthenium- phosphine distances are
2.310(3) and 2.346(2) �, but that which is trans
to the oxygen is unusually short, being 2 219(2) �. The ruthenium-oxygen
distance is 2.166(5)�.
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50
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Abstract
The crystal structure of
the title compound, (NH4)Ag(SCN)2, has been redetermined at 295(1) K. Crystals are monoclinic, P21/n,
a 7.207(4), b 23.84(1), c 4.014(4) �,
β 95.24(7)�, Z 4. The structure comprises two-dimensional polymeric anion
layers parallel to ac, interleaved by
N. . .H hydrogen-bonded ammonium cations. The silver atom is pseudo-tetrahedrally four-coordinated by terminal and triply
bridging S thiocyanate groups (Ag-S, 2.469(4);
2.609-2.773(5) �). The structure was refined
to a residual of 0.051 for 550 'observed' reflections.
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