The Experts below are selected from a list of 228 Experts worldwide ranked by ideXlab platform
Robert H. Poppenga - One of the best experts on this subject based on the ideXlab platform.
-
Successful Management of Severe Bromethalin Toxicosis in a Dog
Journal of the American Animal Hospital Association, 2019Co-Authors: Bridget M. Lyons, Robert H. Poppenga, Vincent J. Thawley, Lori S. WaddellAbstract:ABSTRACT The use of Bromethalin rodenticides has risen since 2011, and in some states, it is the most common rodenticide ingestion reported to poison control. Although intravenous lipid emulsion (ILE) has been previously reported to lower serum desmethylBromethalin levels in an asymptomatic dog, and repeated mannitol has been investigated in a laboratory setting, there are no published reports of successful treatment of symptomatic Bromethalin toxicosis in dogs. A 9 yr old castrated male Norwich terrier was evaluated for obtunded mentation, seizures, cranial nerve deficits, and tetraparesis secondary to Bromethalin toxicosis. The patient was treated with ILE, mannitol, and ginkgo biloba and returned to normal neurological function. Bromethalin exposure was confirmed by serum desmethylBromethalin levels. Previous literature indicates that the prognosis for patients who suffer from symptomatic Bromethalin toxicosis is poor to grave, and the return to normal neurological function after severe toxicosis has not been reported. ILE, mannitol, and ginkgo biloba are readily available and relatively inexpensive, and in combination may be of benefit in symptomatic Bromethalin intoxication.
-
successful management of severe Bromethalin toxicosis in a dog
Journal of The American Animal Hospital Association, 2019Co-Authors: Bridget M. Lyons, Robert H. Poppenga, Vincent J. Thawley, Lori S. WaddellAbstract:ABSTRACTThe use of Bromethalin rodenticides has risen since 2011, and in some states, it is the most common rodenticide ingestion reported to poison control. Although intravenous lipid emulsion (IL...
-
Fatal Bromethalin intoxication in 3 cats and 2 dogs with minimal or no histologic central nervous system spongiform change.
Journal of veterinary diagnostic investigation : official publication of the American Association of Veterinary Laboratory Diagnosticians Inc, 2018Co-Authors: Megan C. Romano, M. S. Filigenzi, Birgit Puschner, Alan T. Loynachan, Dave C. Bolin, Uneeda K. Bryant, Laura Kennedy, Robert H. Poppenga, Cynthia L. GaskillAbstract:Use of the neurotoxic rodenticide Bromethalin has steadily increased since 2011, resulting in an increased incidence of Bromethalin intoxications in pets. Presumptive diagnosis of Bromethalin toxicosis relies on history of possible rodenticide exposure coupled with compatible neurologic signs or sudden death, and postmortem examination findings that eliminate other causes of death. Diagnosis is confirmed by detecting the metabolite desmethylBromethalin (DMB) in tissues. In experimental models, spongiform change in white matter of the central nervous system (CNS) is the hallmark histologic feature of Bromethalin poisoning. We describe fatal Bromethalin intoxication in 3 cats and 2 dogs with equivocal or no CNS white matter spongiform change, illustrating that the lesions described in models can be absent in clinical cases of Bromethalin intoxication. Cases with history and clinical signs compatible with Bromethalin intoxication warrant tissue analysis for DMB even when CNS lesions are not evident.
-
New Rodenticide on the Block: Diagnosing Bromethalin Intoxication in Wildlife
Proceedings of the Vertebrate Pest Conference, 2016Co-Authors: Stella C. Mcmillin, Leslie W. Woods, Melanie S. Piazza, Robert H. PoppengaAbstract:Author(s): McMillin, Stella; Piazza, Melanie S.; Woods, Leslie W.; Poppenga, Robert H. | Abstract: Bromethalin is being used more widely for commensal rodent control because of increased regulation on second-generation anticoagulant rodenticides. Wildlife losses in California are tracked by the California Department of Fish and Wildlife. Bromethalin is a neurotoxicant which is not thought to cause secondary poisoning. From August 2014 to January 2016, 24 cases of Bromethalin intoxication were investigated in California. These include 11 raccoons, 11 striped skunks, one gray fox, and one fox squirrel. Most of these occurred in Marin County, where active surveillance of wildlife for rodenticide exposure is occurring. Bromethalin exposure should be evaluated when a wild animal that may have accessed bait is showing neurological signs. Trauma and distemper should be ruled out. Histological changes may be found in the central nervous system but are not always present. The tissue of choice for toxicological analysis is adipose. It is likely that Bromethalin intoxication is under-reported in the rest of the state and may be mistaken for distemper infection or trauma. Primary exposure of wildlife to Bromethalin could be prevented by placing baits in tamper-resistant bait stations.
-
Method for the Detection of DesmethylBromethalin in Animal Tissue Samples for the Determination of Bromethalin Exposure
Journal of agricultural and food chemistry, 2015Co-Authors: Michael S. Filigenzi, Adrienne C. Bautista, Linda S. Aston, Robert H. PoppengaAbstract:Bromethalin, a potent neurotoxin, is widely available for use as a rodenticide. As access to other rodenticides is reduced due to regulatory pressure, the use of Bromethalin is likely to increase with a concomitant increase in poisonings in nontarget animals. Analytical methods for the detection of Bromethalin residues in animals suspected to have been exposed to this rodenticide are needed to support post-mortem diagnosis of toxicosis. This paper describes a novel method for the analysis of desmethylBromethalin (DMB), Bromethalin’s toxic metabolite, in tissue samples such as liver, brain, and adipose. Samples were extracted with 5% ethanol in ethyl acetate, and an aliquot of the extract was evaporated dry, reconstituted, and analyzed by reverse phase ultrahigh-performance liquid chromatography–mass spectrometry. The mass spectrometer utilized electrospray ionization in negative ion mode with multiple reaction monitoring. This method was qualitatively validated at a level of 1.0 ng/g in liver tissue. The ...
Malgorzata Johnson - One of the best experts on this subject based on the ideXlab platform.
-
Thin layer chromatography convulsant screen extended by gas chromatography-mass spectrometry.
Journal of veterinary diagnostic investigation : official publication of the American Association of Veterinary Laboratory Diagnosticians Inc, 2003Co-Authors: W. Emmett Braselton, Malgorzata JohnsonAbstract:Acute onset convulsive disorders in the canine may result from exposure to a variety of toxicants including strychnine, insecticides, metaldehyde, zinc phosphide, methylxanthines, drugs of abuse, Bromethalin, and the tremorgenic mycotoxins (roquefortine and penitrem A). Although several of the above can be identified in a single gas chromatography-mass spectrometry (GC-MS) screen most have to be determined by separate tests. This report describes a modification of the strychnine extraction procedure, which allows thin layer chromatographic (TLC) identification of strychnine, Bromethalin, roquefortine, and penitrem A in suspect baits, stomach contents or vomitus, and extends the identification to a wide variety of drugs, pesticides, and environmental contaminants by GC-MS. Samples were mixed with base, extracted into CH2Cl2 and the organic fraction back-extracted with acid. The organic fraction (neutrals) was purified by gel permeation chromatography (GPC) and analyzed by TLC to determine penitrem A and br...
-
BRIEF COMMUNICATIONS Thin layer chromatography convulsant screen extended by gas chromatography-mass spectrometry
2003Co-Authors: W. Emmett Braselton, Malgorzata JohnsonAbstract:Acute onset convulsive disorders in the canine may result from exposure to a variety of toxicants including strychnine, insecticides, metaldehyde, zinc phosphide, methylxanthines, drugs of abuse, Bromethalin, and the tremorgenic mycotoxins (roquefortine and penitrem A). Although several of the above can be identified in a single gas chromatography-mass spectrometry (GC-MS) screen most have to be determined by separate tests. This report describes a modification of the strychnine extraction procedure, which allows thin layer chromatographic (TLC) identification of strychnine, Bromethalin, roquefortine, and penitrem A in suspect baits, stomach contents or vomitus, and extends the identification to a wide variety of drugs, pesticides, and environ- mental contaminants by GC-MS. Samples were mixed with base, extracted into CH2Cl2 and the organic fraction back-extracted with acid. The organic fraction (neutrals) was purified by gel permeation chromatography (GPC) and analyzed by TLC to determine penitrem A and Bromethalin. The acidic aqueous fraction was adjusted to pH . 9 and extracted into CH2Cl2. The resulting CH2Cl2 layer (bases) was then analyzed by TLC to determine strychnine and roquefortine. The organic basic and neutral fractions were recombined with a late eluting GPC fraction and analyzed by GC-MS. Of 312 samples analyzed by TLC from 1995 to 2001, 35 were positive for strychnine alone, 58 were positive for both roquefortine and penitrem A, 4 were positive for roquefortine alone, and 1 was positive for Bromethalin. None of the samples were positive for penitrem A alone. Samples negative by TLC were analyzed by the GC-MS extended procedure since mid-1999, and 14 have shown positive for a wide variety of compounds with convulsant activity. Acute onset convulsive disorders in the canine may result from exposure to a variety of toxicants including strychnine, insecticides, metaldehyde, zinc phosphide, methylxanthines, Bromethalin, and the tremorgenic mycotoxins (roquefortine and penitrem A), as well as some human drugs of abuse. 3,4 Several of the above (insecticides, metaldehyde, and drugs of abuse) can be identified in a single gas chromatography-mass spec- trometry (GC-MS) screen, 1 but most have to be deter- mined by individual tests. To identify additional sus- pect toxicants in strychnine negative samples, an ex- traction procedure for neutral compounds as well as alkaloids was developed. 3 This method allowed thin- layer chromatographic (TLC) identification of the tre- morgenic mycotoxins (roquefortine and penitrem A) and the rodenticides (Bromethalin and strychnine) in suspect baits, stomach contents, or vomitus. 2 The pro- cedure has now been further extended by GC-MS to allow identification of additional central nervous sys- tem (CNS) active compounds including drugs, organ- ochlorine, organophosphate (and certain carbamate) insecticides, and metaldehyde. Ten gram samples of bait, stomach contents, or
-
Thin layer chromatography convulsant screen extended by gas chromatography-mass spectrometry.
Journal of veterinary diagnostic investigation : official publication of the American Association of Veterinary Laboratory Diagnosticians Inc, 2003Co-Authors: W. Emmett Braselton, Malgorzata JohnsonAbstract:Acute onset convulsive disorders in the canine may result from exposure to a variety of toxicants including strychnine, insecticides, metaldehyde, zinc phosphide, methylxanthines, drugs of abuse, Bromethalin, and the tremorgenic mycotoxins (roquefortine and penitrem A). Although several of the above can be identified in a single gas chromatography-mass spectrometry (GC-MS) screen most have to be determined by separate tests. This report describes a modification of the strychnine extraction procedure, which allows thin layer chromatographic (TLC) identification of strychnine, Bromethalin, roquefortine, and penitrem A in suspect baits, stomach contents or vomitus, and extends the identification to a wide variety of drugs, pesticides, and environmental contaminants by GC-MS. Samples were mixed with base, extracted into CH2Cl2 and the organic fraction back-extracted with acid. The organic fraction (neutrals) was purified by gel permeation chromatography (GPC) and analyzed by TLC to determine penitrem A and Bromethalin. The acidic aqueous fraction was adjusted to pH > 9 and extracted into CH2Cl2. The resulting CH2Cl2 layer (bases) was then analyzed by TLC to determine strychnine and roquefortine. The organic basic and neutral fractions were recombined with a late eluting GPC fraction and analyzed by GC-MS. Of 312 samples analyzed by TLC from 1995 to 2001, 35 were positive for strychnine alone, 58 were positive for both roquefortine and penitrem A, 4 were positive for roquefortine alone, and 1 was positive for Bromethalin. None of the samples were positive for penitrem A alone. Samples negative by TLC were analyzed by the GC-MS extended procedure since mid-1999, and 14 have shown positive for a wide variety of compounds with convulsant activity.
Richard J Geller - One of the best experts on this subject based on the ideXlab platform.
-
human Bromethalin exposures reported to a u s statewide poison control system
Clinical Toxicology, 2016Co-Authors: Serena Huntington, Yelena Fenik, Rais Vohra, Richard J GellerAbstract:AbstractBackground: Bromethalin is an increasingly used alternative to long-acting anticoagulant and cholecalciferol rodenticides. There are few reports of human exposures, and no existing professional society guidelines on medical management of Bromethalin ingestions. The aim of this retrospective data review is to characterize Bromethalin exposures reported to the California Poison Control System (CPCS) between 1997 and 2014. Methods: This is an observational retrospective case review of our statewide poison control system’s electronic medical records. Following Institutional Board Review and Research Committee approvals, poison center exposures related to Bromethalin were extracted using substance code and free text search strategies. Case notes of Bromethalin exposures were reviewed for demographic, clinical, laboratory, and outcome information; inclusion criteria for the study was single-substance, human exposure to Bromethalin. Results: There were 129 calls related to human Bromethalin exposures (th...
-
Human Bromethalin exposures reported to a U.S. Statewide Poison Control System
Clinical toxicology (Philadelphia Pa.), 2016Co-Authors: Serena Huntington, Yelena Fenik, Rais Vohra, Richard J GellerAbstract:Bromethalin is an increasingly used alternative to long-acting anticoagulant and cholecalciferol rodenticides. There are few reports of human exposures, and no existing professional society guidelines on medical management of Bromethalin ingestions. The aim of this retrospective data review is to characterize Bromethalin exposures reported to the California Poison Control System (CPCS) between 1997 and 2014. This is an observational retrospective case review of our statewide poison control system's electronic medical records. Following Institutional Board Review and Research Committee approvals, poison center exposures related to Bromethalin were extracted using substance code and free text search strategies. Case notes of Bromethalin exposures were reviewed for demographic, clinical, laboratory, and outcome information; inclusion criteria for the study was single-substance, human exposure to Bromethalin. There were 129 calls related to human Bromethalin exposures (three cases met exclusion criteria). The age range of cases was 7 months-90 years old, with the majority of exposures (89 cases; 70.6%), occurring in children younger than 5 years of age (median age of 2 years). Most exposures occurred in the pediatric population as a result of exploratory oral exposure. One hundred and thirteen patients (89.7%) had no effects post exposure, while 10 patients (7.9%) had a minor outcome. Adverse effects were minor, self-limited, and mostly gastrointestinal upset. There were no moderate, major, or fatal effects in our study population. The approximate ingested dose, available in six cases, ranged from 0.067 mg/kg to 0.3 mg/kg (milligrams of Bromethalin ingested per kilogram of body weight), and no dose-symptom threshold could be established from this series. Exposures were not confirmed through urine or serum laboratory testing. The prognosis for most accidental ingestions appears to be excellent. However, Bromethalin exposures may result in a higher number of symptomatic patients than long-acting anticoagulant agents. Parents, physicians and poison control specialists are encouraged to maintain a high index of suspicion for Bromethalin-related complications in all cases of rodenticide exposures. Accidental Bromethalin exposures in children appear to be self-limited in toxicity. Additional studies are warranted to determine whether more severe effects are precipitated when larger amounts are involved, particularly in suicidal ingestion.
John P. Buchweitz - One of the best experts on this subject based on the ideXlab platform.
-
characterization of Bromethalin and its degradation products in veterinary toxicology samples by gc ms ms
Journal of Analytical Toxicology, 2019Co-Authors: Andreas F. Lehner, Mark T. Bokhart, Margaret Johnson, John P. BuchweitzAbstract:Bromethalin is a neurotoxicant with unusual instability and chromatographic behavior that make it difficult to analyze by gas chromatography (GC) in forensic examination of non-target animal deaths. Physicochemical breakdown of Bromethalin produced multiple unique products with discernible mass spectra. This paper describes an investigation of the GC electron impact-mass spectrometric properties of Bromethalin and its capacity to generate up to twenty heat- or light-induced breakdown products. Two principal breakdown products are isomeric with one another and involve release of both fluorine and methyl groups to develop dehydrofluorodesmethylBromethalin products. These compounds have proven to be excellent surrogate markers in screening forensic samples for Bromethalin exposure, particularly in veterinary samples in which the active metabolite desmethylBromethalin has not yet accumulated to any appreciable extent, such as baits and animal stomach contents. The compounds as well as their parent Bromethalin were easily monitored by GC interfaced with a tandem-quadrupole mass spectrometer using multiple-reaction monitoring (MRM) modes. Unusual gas chromatographic properties of Bromethalin included: (i) specific requirements for a maximum oven temperature; (ii) non-linear increases in detector response on increased injection volumes, hypothesized to result from variable diffusion coefficients. We report here the development of GC strategies that facilitate detection of Bromethalin and its breakdown products, as well as their MRM analysis by tandem-quadrupole mass spectrometry. The developed approaches are applicable to feed, baits and stomach contents as well as extracted tissue samples such as liver and kidney.
-
Characterization of Bromethalin and its Degradation Products in Veterinary Toxicology Samples by GC–MS-MS
Journal of analytical toxicology, 2018Co-Authors: Andreas F. Lehner, Mark T. Bokhart, Margaret Johnson, John P. BuchweitzAbstract:Bromethalin is a neurotoxicant with unusual instability and chromatographic behavior that make it difficult to analyze by gas chromatography (GC) in forensic examination of non-target animal deaths. Physicochemical breakdown of Bromethalin produced multiple unique products with discernible mass spectra. This paper describes an investigation of the GC electron impact-mass spectrometric properties of Bromethalin and its capacity to generate up to twenty heat- or light-induced breakdown products. Two principal breakdown products are isomeric with one another and involve release of both fluorine and methyl groups to develop dehydrofluorodesmethylBromethalin products. These compounds have proven to be excellent surrogate markers in screening forensic samples for Bromethalin exposure, particularly in veterinary samples in which the active metabolite desmethylBromethalin has not yet accumulated to any appreciable extent, such as baits and animal stomach contents. The compounds as well as their parent Bromethalin were easily monitored by GC interfaced with a tandem-quadrupole mass spectrometer using multiple-reaction monitoring (MRM) modes. Unusual gas chromatographic properties of Bromethalin included: (i) specific requirements for a maximum oven temperature; (ii) non-linear increases in detector response on increased injection volumes, hypothesized to result from variable diffusion coefficients. We report here the development of GC strategies that facilitate detection of Bromethalin and its breakdown products, as well as their MRM analysis by tandem-quadrupole mass spectrometry. The developed approaches are applicable to feed, baits and stomach contents as well as extracted tissue samples such as liver and kidney.
-
Atypical Bromethalin intoxication in a dog: pathologic features and identification of an isomeric breakdown product
BMC Veterinary Research, 2015Co-Authors: Maria C. Bates, Patrick Roady, Andreas F. Lehner, John P. Buchweitz, B. Heggem-perry, Stephane LezmiAbstract:Background Definitive post mortem confirmation of intoxication by the neurotoxic rodenticide Bromethalin can be challenging. Brain lesions are not specific and detection of Bromethalin and its metabolites are unpredictable due to rapid photodegradation and inconsistent behavior in tissues. Case presentation A 2-year-old dog presented with rapid onset of severe muscle tremors and death within hours after a known ingestion of a reportedly low dosage of Bromethalin and subsequent decontamination using activated charcoal. Marked meningeal hemorrhages and multifocal myelin sheath vacuolation were observed in the brain. A marked reactive astrocytosis and neuronal hypoxia/necrosis were identified using immunohistochemistry (IHC) for glial fibrillary acidic protein (GFAP) and for neuron specific protein (NeuN). Bromethalin exposure and tissue absorption was confirmed by identification of one of two isomeric 543.7 molecular weight (MW) breakdown products in the patient’s adipose and kidney samples using gas chromatography (GC) combined with tandem quadrupole mass spectrometry (MS/MS). Conclusions The severity of clinical signs and subsequent death of this dog was not expected with the low dosage of Bromethalin reportedly ingested, and the use of activated charcoal possibly precipitated a hypernatremic status. Meningeal hemorrhages are atypical of Bromethalin intoxication, and might have been caused by hyperthermia, secondary to tremors or hypernatremia. Identification of one of two isomeric breakdown products in the adipose tissue and kidney provides an additional molecule to the toxicologic testing regime for Bromethalin intoxication.
-
Atypical Bromethalin intoxication in a dog: pathologic features and identification of an isomeric breakdown product
BMC veterinary research, 2015Co-Authors: Maria C. Bates, Patrick Roady, Andreas F. Lehner, John P. Buchweitz, B. Heggem-perry, Stephane LezmiAbstract:Background Definitive post mortem confirmation of intoxication by the neurotoxic rodenticide Bromethalin can be challenging. Brain lesions are not specific and detection of Bromethalin and its metabolites are unpredictable due to rapid photodegradation and inconsistent behavior in tissues.
W. Emmett Braselton - One of the best experts on this subject based on the ideXlab platform.
-
Thin layer chromatography convulsant screen extended by gas chromatography-mass spectrometry.
Journal of veterinary diagnostic investigation : official publication of the American Association of Veterinary Laboratory Diagnosticians Inc, 2003Co-Authors: W. Emmett Braselton, Malgorzata JohnsonAbstract:Acute onset convulsive disorders in the canine may result from exposure to a variety of toxicants including strychnine, insecticides, metaldehyde, zinc phosphide, methylxanthines, drugs of abuse, Bromethalin, and the tremorgenic mycotoxins (roquefortine and penitrem A). Although several of the above can be identified in a single gas chromatography-mass spectrometry (GC-MS) screen most have to be determined by separate tests. This report describes a modification of the strychnine extraction procedure, which allows thin layer chromatographic (TLC) identification of strychnine, Bromethalin, roquefortine, and penitrem A in suspect baits, stomach contents or vomitus, and extends the identification to a wide variety of drugs, pesticides, and environmental contaminants by GC-MS. Samples were mixed with base, extracted into CH2Cl2 and the organic fraction back-extracted with acid. The organic fraction (neutrals) was purified by gel permeation chromatography (GPC) and analyzed by TLC to determine penitrem A and br...
-
BRIEF COMMUNICATIONS Thin layer chromatography convulsant screen extended by gas chromatography-mass spectrometry
2003Co-Authors: W. Emmett Braselton, Malgorzata JohnsonAbstract:Acute onset convulsive disorders in the canine may result from exposure to a variety of toxicants including strychnine, insecticides, metaldehyde, zinc phosphide, methylxanthines, drugs of abuse, Bromethalin, and the tremorgenic mycotoxins (roquefortine and penitrem A). Although several of the above can be identified in a single gas chromatography-mass spectrometry (GC-MS) screen most have to be determined by separate tests. This report describes a modification of the strychnine extraction procedure, which allows thin layer chromatographic (TLC) identification of strychnine, Bromethalin, roquefortine, and penitrem A in suspect baits, stomach contents or vomitus, and extends the identification to a wide variety of drugs, pesticides, and environ- mental contaminants by GC-MS. Samples were mixed with base, extracted into CH2Cl2 and the organic fraction back-extracted with acid. The organic fraction (neutrals) was purified by gel permeation chromatography (GPC) and analyzed by TLC to determine penitrem A and Bromethalin. The acidic aqueous fraction was adjusted to pH . 9 and extracted into CH2Cl2. The resulting CH2Cl2 layer (bases) was then analyzed by TLC to determine strychnine and roquefortine. The organic basic and neutral fractions were recombined with a late eluting GPC fraction and analyzed by GC-MS. Of 312 samples analyzed by TLC from 1995 to 2001, 35 were positive for strychnine alone, 58 were positive for both roquefortine and penitrem A, 4 were positive for roquefortine alone, and 1 was positive for Bromethalin. None of the samples were positive for penitrem A alone. Samples negative by TLC were analyzed by the GC-MS extended procedure since mid-1999, and 14 have shown positive for a wide variety of compounds with convulsant activity. Acute onset convulsive disorders in the canine may result from exposure to a variety of toxicants including strychnine, insecticides, metaldehyde, zinc phosphide, methylxanthines, Bromethalin, and the tremorgenic mycotoxins (roquefortine and penitrem A), as well as some human drugs of abuse. 3,4 Several of the above (insecticides, metaldehyde, and drugs of abuse) can be identified in a single gas chromatography-mass spec- trometry (GC-MS) screen, 1 but most have to be deter- mined by individual tests. To identify additional sus- pect toxicants in strychnine negative samples, an ex- traction procedure for neutral compounds as well as alkaloids was developed. 3 This method allowed thin- layer chromatographic (TLC) identification of the tre- morgenic mycotoxins (roquefortine and penitrem A) and the rodenticides (Bromethalin and strychnine) in suspect baits, stomach contents, or vomitus. 2 The pro- cedure has now been further extended by GC-MS to allow identification of additional central nervous sys- tem (CNS) active compounds including drugs, organ- ochlorine, organophosphate (and certain carbamate) insecticides, and metaldehyde. Ten gram samples of bait, stomach contents, or
-
Thin layer chromatography convulsant screen extended by gas chromatography-mass spectrometry.
Journal of veterinary diagnostic investigation : official publication of the American Association of Veterinary Laboratory Diagnosticians Inc, 2003Co-Authors: W. Emmett Braselton, Malgorzata JohnsonAbstract:Acute onset convulsive disorders in the canine may result from exposure to a variety of toxicants including strychnine, insecticides, metaldehyde, zinc phosphide, methylxanthines, drugs of abuse, Bromethalin, and the tremorgenic mycotoxins (roquefortine and penitrem A). Although several of the above can be identified in a single gas chromatography-mass spectrometry (GC-MS) screen most have to be determined by separate tests. This report describes a modification of the strychnine extraction procedure, which allows thin layer chromatographic (TLC) identification of strychnine, Bromethalin, roquefortine, and penitrem A in suspect baits, stomach contents or vomitus, and extends the identification to a wide variety of drugs, pesticides, and environmental contaminants by GC-MS. Samples were mixed with base, extracted into CH2Cl2 and the organic fraction back-extracted with acid. The organic fraction (neutrals) was purified by gel permeation chromatography (GPC) and analyzed by TLC to determine penitrem A and Bromethalin. The acidic aqueous fraction was adjusted to pH > 9 and extracted into CH2Cl2. The resulting CH2Cl2 layer (bases) was then analyzed by TLC to determine strychnine and roquefortine. The organic basic and neutral fractions were recombined with a late eluting GPC fraction and analyzed by GC-MS. Of 312 samples analyzed by TLC from 1995 to 2001, 35 were positive for strychnine alone, 58 were positive for both roquefortine and penitrem A, 4 were positive for roquefortine alone, and 1 was positive for Bromethalin. None of the samples were positive for penitrem A alone. Samples negative by TLC were analyzed by the GC-MS extended procedure since mid-1999, and 14 have shown positive for a wide variety of compounds with convulsant activity.
