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Stefan Endepols - One of the best experts on this subject based on the ideXlab platform.
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the potential of Coumatetralyl enhanced by cholecalciferol in the control of anticoagulant resistant norway rats rattus norvegicus
Pest Management Science, 2017Co-Authors: Stefan Endepols, Nicole Klemann, Dania Richter, Franz-rainer MatuschkaAbstract:BACKGROUND We evaluated the potential of cholecalciferol as an enhancer of the first-generation anticoagulant Coumatetralyl in the Westphalia anticoagulant-resistant strain of the Norway rat (Rattus norvegicus Berkenhout), characterised by the Tyr139Cys polymorphism on the VKOR enzyme. Because today only the most potent, but also most persistent anticoagulant rodenticides of the second generation remain available to control this strain, new rodenticide solutions are required. RESULTS Feeding trials in the laboratory confirmed a significant level of efficacy, which was corroborated by field trials in the Munsterland resistance area. After frequency and level of resistance were assessed by blood clotting response tests, field trials were conducted with bait containing Coumatetralyl at 375 mg kg−1 and cholecalciferol at 50 mg kg−1 or 100 mg kg−1. Control success was 94% when a large rat infestation comprising 42% resistant animals was treated. Another field trial applying the combination to a rat population that had survived a preceding treatment with bromadiolone resulted in a 99.5% control success according to the first census day, but with some increase in rat activity during subsequent census days. CONCLUSION The combination of Coumatetralyl and cholecalciferol is a promising alternative approach to the most potent second-generation anticoagulants in resistance management, particularly in respect of environmental risks, such as secondary poisoning. © 2016 Society of Chemical Industry
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The potential of Coumatetralyl enhanced by cholecalciferol in the control of anticoagulant‐resistant Norway rats (Rattus norvegicus)
Pest Management Science, 2016Co-Authors: Stefan Endepols, Nicole Klemann, Dania Richter, Franz-rainer MatuschkaAbstract:BACKGROUND We evaluated the potential of cholecalciferol as an enhancer of the first-generation anticoagulant Coumatetralyl in the Westphalia anticoagulant-resistant strain of the Norway rat (Rattus norvegicus Berkenhout), characterised by the Tyr139Cys polymorphism on the VKOR enzyme. Because today only the most potent, but also most persistent anticoagulant rodenticides of the second generation remain available to control this strain, new rodenticide solutions are required. RESULTS Feeding trials in the laboratory confirmed a significant level of efficacy, which was corroborated by field trials in the Munsterland resistance area. After frequency and level of resistance were assessed by blood clotting response tests, field trials were conducted with bait containing Coumatetralyl at 375 mg kg−1 and cholecalciferol at 50 mg kg−1 or 100 mg kg−1. Control success was 94% when a large rat infestation comprising 42% resistant animals was treated. Another field trial applying the combination to a rat population that had survived a preceding treatment with bromadiolone resulted in a 99.5% control success according to the first census day, but with some increase in rat activity during subsequent census days. CONCLUSION The combination of Coumatetralyl and cholecalciferol is a promising alternative approach to the most potent second-generation anticoagulants in resistance management, particularly in respect of environmental risks, such as secondary poisoning. © 2016 Society of Chemical Industry
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Susceptibility to the anticoagulants bromadiolone and Coumatetralyl in wild Norway rats ( Rattus norvegicus ) from the UK and Germany
International Journal of Pest Management, 2007Co-Authors: Stefan Endepols, Colin V. Prescott, Nicole Klemann, Alan BuckleAbstract:Abstract A new blood clotting response test was used to determine the susceptibility, to Coumatetralyl and bromadiolone, of laboratory strains of Norway rat from Germany and the UK (Hampshire), and wild rats trapped on farms in Wales (UK) and Westphalia (Germany). Resistance factors were calculated in relation to the CD strain of Norway rat. An outbred strain of wild rats, raised from rats trapped in Germany, was found to be more susceptible to Coumatetralyl by a factor of 0.5 – 0.6 compared to the CD strain. Homozygous and heterozygous animals of a strain of resistant rats from Westphalia were cross-resistant to Coumatetralyl and bromadiolone, with a higher resistance factor for bromadiolone than that found in both UK strains. Our results show that the degree of altered susceptibility and resistance varies between strains of wild rat and between resistance foci. Some wild rat strains may be more susceptible than laboratory rat strains. Even in a well-established resistance area, it may be difficult to fi...
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Evaluation of secondary poisoning hazards to ferrets and weka from the rodenticide Coumatetralyl
Wildlife Research, 2003Co-Authors: Cheryl E. O'connor, Charles Eason, Stefan EndepolsAbstract:We investigated the secondary poisoning hazards of the rodenticide Coumatetralyl to a predatory and scavenging mammal and bird. Wistar rats, which had been poisoned with Racumin® baits containing 375 ppm Coumatetralyl, were fed to 10 captive ferrets (Mustela furo) and 10 weka (Gallirallus australis) for 3 consecutive days. Nine ferrets ate 764 ± 95 g kg–1 (83% by weight) of the rat carcasses offered and two died. Weka ate 258 ± 32 g kg–1 (25% by weight) of the rat carcasses, preferring the internal organs. There were no deaths and no obvious signs of ill health in any weka. These results suggest that predatory and scavenging bird and mammal species, in general, will be placed only at comparatively low risk from secondary poisoning from Coumatetralyl.
Hee-myung Park - One of the best experts on this subject based on the ideXlab platform.
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Coumatetralyl rodenticide induced pericardial effusion — A reply
Canadian Veterinary Journal-revue Veterinaire Canadienne, 2011Co-Authors: Hee-myung ParkAbstract:Dear Sir, Thank you for your considerate comment. As you mentioned, high cTn I level in our case would be more similar to the hemangiosarcoma group than the idiopathic pericardial effusion group in the study reported in reference 1. However, because our case did not have any cardiac mass echocardiographically and had an obvious causative history, this patient would not be considered to have induced pericardial effusion by hemangiosarcoma. Besides, both of these references (1,2) did not involve the cTnI level of pericardial effusion caused by rodenticide. However, we would like to correct the statement as follows. “High cTnI level (5.42 ng/mL) in our patient was more similar to the value with hemangiosarcoma than idiopathic pericardial effusion.”
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Coumatetralyl rodenticide induced pericardial effusion a reply
Canadian Veterinary Journal-revue Veterinaire Canadienne, 2011Co-Authors: Hee-myung ParkAbstract:Dear Sir, Thank you for your considerate comment. As you mentioned, high cTn I level in our case would be more similar to the hemangiosarcoma group than the idiopathic pericardial effusion group in the study reported in reference 1. However, because our case did not have any cardiac mass echocardiographically and had an obvious causative history, this patient would not be considered to have induced pericardial effusion by hemangiosarcoma. Besides, both of these references (1,2) did not involve the cTnI level of pericardial effusion caused by rodenticide. However, we would like to correct the statement as follows. “High cTnI level (5.42 ng/mL) in our patient was more similar to the value with hemangiosarcoma than idiopathic pericardial effusion.”
Giuliano Bandoli - One of the best experts on this subject based on the ideXlab platform.
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x ray structures of the anticoagulants Coumatetralyl and chlorophacinone theoretical calculations and sar investigations on thirteen anticoagulant rodenticides
Journal of Molecular Structure, 1999Co-Authors: Alessandro Dolmella, Stefano Gatto, Enrico Girardi, Giuliano BandoliAbstract:Abstract Coumatetralyl and chlorophacinone, two substances related to 4-hydroxycoumarin (HC) and to 1,3-indandione (ID), respectively, show activity as anticoagulant rodenticides. In the present study we have investigated the solid-state structures of Coumatetralyl and chlorophacinone by means of X-ray single-crystal and powder diffraction, along with thermal analysis. The crystal structures of the two compounds have been used as input geometries for a series of computational chemistry efforts, involving other anticoagulant derivatives as well. Thus, ab initio, semiempirical molecular orbital, molecular mechanics and molecular dynamics/simulated annealing calculations have been performed on thirteen anticoagulant rodenticides. In particular, the annealing calculations have been made to assess the conformational freedom of the compounds under scrutiny. All the generated conformers have been classified into families. The classification has first been made empirically, and then validated by means of a cluster analysis. A number of structural and physico-chemical parameters derived from the calculations has been used in turn for structure–activity relationships (SARs) investigations. In the latter, we have assessed how the selected parameters affect toxicity. The results seem to be consistent with a three-dimensional biophore model, in which higher toxicity is predicted for the more voluminous rodenticides. We suggest that these compounds better fit the active site of the target enzyme vitamin K 2,3-epoxide reductase (KO-reductase).
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X-ray structures of the anticoagulants Coumatetralyl and chlorophacinone. Theoretical calculations and SAR investigations on thirteen anticoagulant rodenticides
Journal of Molecular Structure, 1999Co-Authors: Alessandro Dolmella, Stefano Gatto, Enrico Girardi, Giuliano BandoliAbstract:Coumatetralyl and chlorophacinone, two substances related to 4-hydroxycoumarin (HC) and to 1,3-indandione (ID), respectively, show activity as anticoagulant rodenticides. In the present study we have investigated the solid-state structures of Coumatetralyl and chlorophacinone by means of X-ray single-crystal and powder diffraction, along with thermal analysis. The crystal structures of the two compounds have been used as input geometries for a series of computational chemistry efforts, involving other anticoagulant derivatives as well. Thus, ab initio, semiempirical molecular orbital, molecular mechanics and molecular dynamics/simulated annealing calculations have been performed on thirteen anticoagulant rodenticides. In particular, the annealing calculations have been made to assess the conformational freedom of the compounds under scrutiny. All the generated conformers have been classified into families. The classification has first been made empirically, and then validated by means of a cluster analysis. A number of structural and physico-chemical parameters derived from the calculations has been used in turn for structure-activity relationships (SARs) investigations. In the latter, we have assessed how the selected parameters affect toxicity. The results seem to be consistent with a three-dimensional biophore model, in which higher toxicity is predicted for the more voluminous rodenticides. We suggest that these compounds better fit the active site of the target enzyme vitamin K 2,3-epoxide reductase (KO-reductase). (C) 1999 Elsevier Science B.V. All rights reserved
Xiao-hong Chen - One of the best experts on this subject based on the ideXlab platform.
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Rapid Determination of Coumatetralyl in Human Serum by High‐Performance Liquid Chromatography Coupled with Electrospray Ionization Tandem Mass Spectrometry
Analytical Letters, 2007Co-Authors: Micong Jin, Xiao-kun Ouyang, Yi-ping Ren, Xiao-hong ChenAbstract:Abstract A rapid, sensitive, and selective high‐performance liquid chromatography‐tandem mass spectrometric method (HPLC‐MS‐MS) for the determination of Coumatetralyl in human serum using warfarin as an internal standard has been developed and validated. Coumatetralyl and the internal standard were extracted from the human serum samples by liquid‐liquid extraction with ethyl acetate, followed by separation on a XDB C18 reversed‐phase column (150 mm×2.1 mm i.d., 5 µm) using a mobile phase consisting of acetic acid‐ammonium acetate (5 mmol/L, pH=4.5)/methanol (20:80, v/v) at a constant flow rate of 0.40 mL/min. Coumatetralyl and the internal standard were ionized by negative ion pneumatically assisted electrospray and detected in the multiple‐reaction monitoring mode using precursor→product ion combinations at m/z 291→247 and 307→161, respectively. The calibration curve was linear (r2=0.9945) in the concentration range of 0.5∼100.0 ng/mL, with a lower limit of quantification of 0.5 ng/mL in human serum. Int...
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rapid determination of Coumatetralyl in human serum by high performance liquid chromatography coupled with electrospray ionization tandem mass spectrometry
Analytical Letters, 2007Co-Authors: Micong Jin, Xiao-kun Ouyang, Yi-ping Ren, Xiao-hong ChenAbstract:Abstract A rapid, sensitive, and selective high‐performance liquid chromatography‐tandem mass spectrometric method (HPLC‐MS‐MS) for the determination of Coumatetralyl in human serum using warfarin as an internal standard has been developed and validated. Coumatetralyl and the internal standard were extracted from the human serum samples by liquid‐liquid extraction with ethyl acetate, followed by separation on a XDB C18 reversed‐phase column (150 mm×2.1 mm i.d., 5 µm) using a mobile phase consisting of acetic acid‐ammonium acetate (5 mmol/L, pH=4.5)/methanol (20:80, v/v) at a constant flow rate of 0.40 mL/min. Coumatetralyl and the internal standard were ionized by negative ion pneumatically assisted electrospray and detected in the multiple‐reaction monitoring mode using precursor→product ion combinations at m/z 291→247 and 307→161, respectively. The calibration curve was linear (r2=0.9945) in the concentration range of 0.5∼100.0 ng/mL, with a lower limit of quantification of 0.5 ng/mL in human serum. Int...
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Solid phase extraction--HPLC in determination of Coumatetralyl in urine
Chinese Journal of Industrial Hygiene and Occupational Diseases, 2006Co-Authors: Micong Jin, Li Wang, Xiao-hong ChenAbstract:目的 建立简便、灵敏、准确的测定尿液中痕量杀鼠萘的固相萃取-高效液相色谱检测方法.方法 尿液样品经Oasis(r)HLB小柱富集,以甲醇-甲基叔丁基醚洗脱,挥干溶剂后以甲醇-乙酸为流动相,采用XDBC18柱(150mm×2.1mm×5μm)分离,二极管阵列(DAD)308 nm检测.结果 杀鼠萘在0.01～10.00 mg/L范围具有良好的线性关系,尿液中定量检测下限为0.005 mg/L,方法回收率为87.5%～98.4%,相对标准偏差小于7.3%.结论 该法灵敏度高、操作简便、快速、准确,适用于作业工人的体检与中毒患者的临床诊断检测。
Louis Pinault - One of the best experts on this subject based on the ideXlab platform.
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Reversed-Phase HPLC Determination of Eight Anticoagulant Rodenticides in Animal Liver
Journal of Analytical Toxicology, 1997Co-Authors: V. Fauconnet, Herve Pouliquen, Louis PinaultAbstract:A reversed-phase high-performance liquid chromatographic method was developed for the analysis of eight anticoagulant rodenticides in animal liver. Coumarinic anticoagulant rodenticides (brodifacoum, bromadiolone, coumachlor, Coumatetralyl, difenacoum, and warfarin) were detected by using a gradient elution and a fluorimetric detection. Indanedione anticoagulant rodenticides (chlorophacinone and diphacinone) were detected by using an isocratic elution and
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Reversed-Phase HPLC Determination of Eight Anticoagulant Rodenticides in Animal Liver
Journal of Analytical Toxicology, 1997Co-Authors: V. Fauconnet, Herve Pouliquen, Louis PinaultAbstract:A reversed-phase high-performance liquid chromatographic method was developed for the analysis of eight anticoagulant rodenticides in animal liver. Coumarinic anticoagulant rodenticides (brodifacoum, bromadiolone, coumachlor, Coumatetralyl, difenacoum, and warfarin) were detected by using a gradient elution and a fluorimetric detection. Indanedione anticoagulant rodenticides (chlorophacinone and diphacinone) were detected by using an isocratic elution and an UV detection. Anticoagulants were extracted from liver with mixtures of acetone/diethylether and acetone/chloroform. Extracts were applied to solid-phase extraction cartridges. Linearity was checked over the concentration range 0.1-0.6 microgram/g. Relative standard deviations of within-run and between-run variability were all between 5.7 and 10.3%. Recoveries from spiked liver samples were between 51.7 (difenacoum) and 78.2% (warfarin). Limits of detection were between 0.01 (difenacoum and warfarin) and 0.11 microgram/g (chlorophacinone).
