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Robert H Poppenga

Publications and source records attributed to Robert H Poppenga.

16 recordsLinked to original sources
PubMed2006

LC-MS/MS screen for penitrem A and roquefortine C in serum and urine samples.

A rapid LC-MS/MS method, using a triple quadrupole/linear ion trap mass spectrometer, was developed for determination of penitrem A and roquefortine C in serum and urine samples. Penitrem A and roquefortine C were extracted from samples with methylene chloride. The extracts were injected onto a liquid chromatograph coupled with a hybrid triple quadrupole/linear ion trap mass spectrometer. Seven replicate fortifications of serum at 0.001 microg/g (1 ppb) each of penitrem A and roquefortine C gave average recoveries of 90% with 10% CV (relative standard deviation) and 97% with 3% CV, respectively. Seven replicate fortifications of urine at 0.001 microg/g (1 ppb) each of penitrem A and roquefortine C gave average recoveries of 98% with 12% CV and 100% with 6% CV, respectively. This is the first report of a positive mass spectrometric identification and quantitation of both compounds in urine and serum samples from dog intoxication cases.

Animals↗
PubMed2006

Chlorophacinone exposure causing an epizootic of acute fatal hemorrhage in lambs.

This report describes an epizootic of chlorophacinone toxicosis in lambs with severe acute hemorrhages. Eleven lambs, approximately 1-2 months of age, suddenly developed epistaxis, respiratory distress, and facial and cervical swelling. Affected animals died within 1-2 hours from the onset of clinical signs. Two lambs were available for complete postmortem examination. Gross lesions included mucosal and organ pallor, icterus, melena, and lung edema, as well as thymic, cervical muscle, and intra-articular hemorrhage. Histologically hepatocellular centrolobular necrosis was observed. The anticoagulant chlorophacinone was detected in the livers at 0.58 ppm and 0.50 ppm (wet weight), respectively. The source of exposure to chlorophacinone was old bait material placed between the wall studs of the building housing the ewes and lambs. The lambs were able to reach the bait through a hole in the plywood interior wall of the building.

Animals↗
PubMed2006

Avian vacuolar myelinopathy outbreaks at a southeastern reservoir.

Avian vacuolar myelinopathy (AVM) is a neurologic disease of unknown etiology that affects bald eagles (Haliaeetus leucocephalus), American coots (Fulica americana), and several species of waterfowl. An unidentified neurotoxin is suspected as the cause of AVM, which has been documented at several reservoirs in the southeastern United States. We conducted diagnostic and epidemiologic studies annually during October-March from 1998-2004 at Clarks Hill/Strom Thurmond Lake on the Georgia/South Carolina border to better understand the disease. Avian vacuolar myelinopathy was confirmed or suspected as the cause of morbidity and mortality of 28 bald eagles, 16 Canada geese (Branta canadensis), six American coots, two great-horned owls (Bubo virginianus), and one killdeer (Charadrius vociferus). Active surveillance during the outbreaks yielded annual average prevalence of vacuolar lesions in 17-94% of coots, but not in 10 beavers (Castor canadensis), four raccoons (Procyon lotor), and one gray fox (Urocyon cinereoargenteus) collected for the study. Brain lesions were not apparent in 30 Canada geese collected and examined in June 2002. The outbreaks at this location from 1998-2004 represent the most significant AVM-related bald eagle mortality since the Arkansas epornitics of 1994-95 and 1996-97, as well as the first confirmation of the disease in members of Strigiformes and Charadriiformes.

Animals↗
PubMed2005

Multi-residue determination of anti-inflammatory analgesics in sera by liquid chromatography--mass spectrometry.

Non-steroidal anti-inflammatories (NSAIDs) are analgesic, antipyretic, and, as their name implies, anti-inflammatory drugs, which are widely used for the treatment of a variety of human and veterinary disease conditions in which control of pain and inflammation is desired. Acetaminophen (ACE) is a common over-the-counter analgesic. Detection of a variety of widely used NSAIDs and ACE in fluid and tissue samples is an important diagnostic tool. A sensitive and selective analytical method has been developed for simultaneous screening of 12 NSAIDs and ACE by liquid chromatography-mass spectrometry with an atmospheric pressure chemical ionization interface set to operate in the negative ion mode of MS. Following sample preparation, all analytes were separated on a C18-reversed-phase column with a gradient elution of acetonitrile and acetic acid. Full-scan mass spectral fragmentation profiles were established for each analyte and individual extracted ion chromatograms were used for quantitation. Linearity of detection was observed over the 0.05-25.0 microg/mL range of standard concentrations. The instrument limits of detection (LOD), based on an individual analyte quantitation ions, fell between 0.05 and 1.0 microg/mL for all compounds. The matrix LODs were determined to be 0.05 microg/mL for phenylbutazone (m/z 307); 0.1 microg/mL for indomethacin (m/z 312), flunixin (m/z 295), and piroxicam (m/z 330); 0.5 microg/mL for ACE (m/z 150), diclofenac (m/z 250), ketoprofen (m/z 209), and mefenamic acid (m/z 240); 1.0 microg/mL for oxyphenbutazone (m/z 323); 5.0 microg/mL for ibuprofen (m/z 205), salicylic acid (m/z 137), and tolmetin (m/z 212); and 10 microg/mL for naproxen (m/z 185).

Acetaminophen↗
PubMed2005

Determination of acepromazine, ketamine, medetomidine, and xylazine in serum: multi-residue screening by liquid chromatography-mass spectrometry.

A large variety of drugs are administered to large and small animals by veterinary clinicians for sedation, anesthesia, muscle relaxation, and analgesia. The present paper reports a simple and rapid multi-residue detection and quantitation method for four chemically different drugs: medetomidine, xylazine, ketamine, and acepromazine. Chromatographic separation was carried out on a liquid chromatography-mass spectrometry instrument with a C18-reversed-phase column. Fragmentation patterns were determined with atmospheric pressure chemical ionization mass spectrometry set to operate in a positive selective ion monitoring mode. The method was determined to be linear over the range of concentrations tested (2.0-100.0 ng/mL). Accuracy, precision, and specificity were evaluated and the method was determined to be applicable to detection of medetomidine, xylazine, ketamine, and acepromazine in serum samples of multiple animal species (canine, equine, and bovine). Matrix limits of quantitation were determined to be 5.0 ng/mL for all four analytes, and recoveries ranged between 82.0 and 118%, with a 3.0-18.3% relative standard deviation.

Acepromazine↗
PubMed2005

Psittacine plasma concentrations of elements: daily fluctuations and clinical implications.

During the past 2 decades, the potential for excessive exposure of pet birds to zinc has become a concern for many pet bird owners. Ideally, avian zinc toxicosis is diagnosed on the basis of history of exposure to zinc, radiographic evidence of ingested metal, occurrence of melena, detection of an elevated plasma zinc concentration, and response to treatment. However, most pet birds suspected of having zinc toxicosis present with vague signs and lack of radiographic evidence; therefore, the diagnosis relies on the presence of an elevated plasma zinc concentration. A question was, is there a significant diurnal variation in the zinc concentration in psittacine birds and could this be clinically relevant? Because studies in other species have shown that zinc is not the only element that shows a diurnal variation, the authors examined 13 other plasma elements including arsenic, cadmium, calcium, cobalt, copper, iodine, iron, magnesium, manganese, molybdenum, potassium, selenium, and total phosphorus. Fifteen adult psittacine birds housed in the same aviary were used in this study. Three blood samples, separated by 4 hours, were taken from the right jugular vein in each bird. All elements were measured in plasma. Zinc, copper, and molybdenum revealed diurnal fluctuations. The results of this study suggest that interpretation of clinical samples may be more complicated than previously believed. Furthermore, on the basis of the results of this study, it is possible that some avian reference ranges may need to be reexamined.

Animals↗
PubMed2005

Comparison of selenium determination in liver samples by atomic absorption spectroscopy and inductively coupled plasma-mass spectrometry.

Selenium (Se) is an essential trace element that is often deficient in the natural diets of domestic animal species. The measurement of Se in whole blood or liver is the most accurate way to assess Se status for diagnostic purposes. This study was conducted to compare hydride generation atomic absorption spectroscopy (HG-AAS) with inductively coupled plasma-mass spectrometry (ICP-MS) for the detection and quantification of Se in liver samples. Sample digestion was accomplished with magnesium nitrate and nitric acid for HG-AAS and ICP-MS, respectively. The ICP-MS detection was optimized for 82Se with yttrium used as the internal standard and resulted in a method detection limit of 0.12 microg/g. Selenium was quantified by both methods in 310 samples from a variety of species that were submitted to the Toxicology Laboratory at New Bolton Center (Kennett Square, PA) for routine diagnostic testing. Paired measurements for each sample were evaluated by a mean difference plot method. Limits of agreement were used to describe the maximum differences likely to occur between the 2 methods. Results suggest that under the specified conditions ICP-MS can be reliably used in place of AAS for quantitation of tissue Se at or below 2 microg/g to differentiate between adequate and deficient liver Se concentrations.

Animals↗
PubMed2005

Zinc phosphide intoxication of wild turkeys (Meleagris gallopavo).

Zinc phosphide (Zn3P2) is a rodenticide used to control a variety of small mammal species. It is available over-the-counter or as a restricted-use pesticide depending on how it is to be applied. The toxicity of Zn3P2 is dependent on the species exposed, whether the animal is able to vomit or not, and whether it is ingested on a full or empty stomach. Nontarget species can be exposed through inadvertent or intentional product misapplication. In this article we describe four mortality events in which wild turkeys (Meleagris gallopavo) were believed to have been intoxicated following the ingestion of baits containing Zn3P2.

Animals↗
PubMed2004

Detection of nonesterified (free) fatty acids in bovine serum: comparative evaluation of two methods.

A method comparison study for the determination and quantitation of nonesterified fatty acids (NEFAs) in serum, using the commercial "NEFA C" enzymatic test kit, was performed using the spectrophotometric method recommended by the manufacturer and a modified procedure optimized for the use of a microplate reader, a 96-well microtiter plate, and small sample volumes (10 microl). Linearity, sensitivity, and precision using the test kit were determined for each method of detection. The assay was linear from 0 to 1.97 mEq/liter for both procedures, and the limits of detection were determined to be 0.22 (+/- 0.074) and 0.05 (+/- 0.002) mEq/liter for the spectrophotometer and microplate reader, respectively. Pairs of measurements for bovine serum samples were compared and evaluated by a mean difference plot method and not regression analysis, a method that has been shown to be inappropriate for method comparison studies. The difference plot was used to evaluate the systematic bias between the 2 methods. Random error is reported on the basis of SD differences, and "limits of agreement" are used to describe the maximum differences likely to occur between the 2 methods. Results suggest that the microplate reader method can be used reliably in place of the recommended spectrophotometric method. The microplate reader method is preferred because of its high throughput capabilities, simultaneous analysis of all the standards and samples, use of small sample and reagent volumes, and reduction in labor requirements and costs.

Animals↗
PubMed2003

Mortality of common loons in New England, 1987 to 2000.

Diagnostic findings are presented on 522 common loons (Gavia immer) found dead or moribund in New England (Connecticut, Maine, Massachusetts, New Hampshire, Rhode Island, and Vermont, USA) between 1987 and 2000. Common loon numbers and range in New England have decreased from historic levels over the last century due to a number of proposed factors. Goals of this study were to identify and categorize causes of mortality and quantify natural versus anthropogenic causes. The majority of identifiable mortality in chicks was from intraspecific aggression (25%) and other causes of trauma (32%). Death in immature loons was primarily from fungal respiratory disease (20%) and trauma (18%). Causes of adult loon mortality differed significantly in breeding and wintering habitats. Wintering adults primarily died of trauma (17%) and infection (11%) and had significantly poorer body condition than breeding loons. In breeding adults, confirmed and suspected lead toxicosis from ingested fishing weights accounted for almost half of all mortality. Direct anthropogenic factors accounted for 52% of loon mortality in this study. Because of high carcass recovery rates, we believe these data are a good representation of loon mortality in New England. Results highlight the importance of human influences on conservation and management of the common loon in New England.

Animals↗
PubMed2002

Internet resources for veterinary toxicologists.

The informational needs of veterinary toxicologists are diverse due to their involvement in clinical, research and regulatory toxicology. The internet provides an important tool for assessing a wide array of useful toxicologic information that is otherwise not readily available. Internet resources utilized by veterinary toxicologists include governmental, commercial, academic and non-profit websites.

Animals↗
PubMed2002

Herbal medicine: potential for intoxication and interactions with conventional drugs.

The use of herbal remedies for the prevention and treatment of a variety of illnesses in small animals has increased tremendously in recent years. Whereas most herbal remedies, when used as directed and under the supervision of knowledgeable individuals, are safe, the potential for adverse effects or intoxications certainly exists. Due to inherent toxicity, some herbal remedies should not be used under any circumstance. In addition, because nearly all herbal remedies contain multiple, biologically active constituents, interaction with conventional drugs is a concern. It is incumbent upon clinicians to be aware of those herbs that can cause intoxication, and to be cognizant of potential herb-drug interactions. There are a number of evidence-based resources available to assist clinicians in the safe use of herbal remedies.

Animal Diseases↗
PubMed2002

Isolation and multiresidue detection of macrolide endectocides present in animal matrices.

A simple, rapid, and sensitive method for isolation and detection of macrolide endectocides (moxidectin, doramectin, selamectin, ivermectin, and eprinomectin) in animal sera and liver is described. Fortified sera or homogenized liver samples were treated with sodium chloride followed by organic solvent extraction. No additional steps were required prior to analysis. Separation of analytes and collection of mass information was achieved by liquid chromatography/mass spectrometry with positive atmospheric pressure chemical ionization set in selected ion monitoring mode with each sample analysis complete in 15 minutes. Presence of each compound was confirmed based on 2 separate extracted ion profiles. Detection of avermectins and moxidectin in a range of working standards was achieved at 10, 50, and 100 ppb. Quantitation of these compounds in fortified samples was based on standard calibration curves with R2 > 0.99. Detection limits of 10 ppb for ivermectin, moxidectin, and doramectin, 50 ppb for selamectin, and 100 ppb for eprinomectin were achieved in spiked sera. Recoveries of avermectins and moxidectin in 500 ppb fortified sera fell between 61 and 89% (+/-5.7-15.7). Analysis of fortified liver gave comparable results with recovery of selamectin of 83-91% +/- 18.3. A complete mass spectral fragmentation pattern of selamectin and affordable screening method for 6 macrolide endectocides are reported. Method comparison for salt treatment and solid-phase extraction of fortified samples is discussed.

Animals↗
PubMed2002

Clinical and necropsy findings associated with increased mortality among American alligators of Lake Griffin, Florida.

From December, 1997, through November, 2000, 306 deaths were documented among adult and subadult American alligators (Alligator mississippiensis) of Lake Griffin, Florida (USA). Some live alligators were lethargic and unresponsive to approach. To determine the cause, we examined ten alligators captured from Lake Griffin between December 1997 and June 1999. Initially, four alligators, three of which were clinically unresponsive, were sacrificed for routine diagnostic necropsy. The other six Lake Griffin alligators, and five control alligators captured from Lake Woodruff National Wildlife Refuge, Florida, where mortality was negligible, were studied extensively by clinical neurologic examination, electromyography, hematology, serum chemical analyses, and blood culture, then sacrificed and necropsied. Samples of brain, spinal cord, peripheral nerves, skeletal muscle, and major internal organs were examined by light microscopy for abnormalities. Samples of nervous tissue also were examined by electron microscopy, and samples of various tissues were collected for toxicologic analyses. Clinical signs included swimming in circles, inability to submerge, lethargy, weakness, unresponsiveness, slow reflexes, dragging the dorsal surfaces of the hind feet, head tilt, and anisocoria. Lake Griffin alligators had significantly lower distal sciatic nerve conduction velocities than Lake Woodruff alligators, and the most severely affected alligators had the lowest velocities; but morphologic abnormalities in peripheral nerves were not evident in most cases. Three severely affected alligators had acute focal necrosis of the torus semicircularis in the midbrain, two had skeletal myofiber atrophy, another had diffuse nonsuppurative encephalomyelitis, and one mildly affected alligator had skeletal myodegeneration. The cause or causes have not yet been identified.

Alligators and Crocodiles↗
PubMedDate not supplied

Direct and rapid determination of baclofen (Lioresal) and carisoprodol (Soma) in bovine serum by liquid chromatography-mass spectrometry.

Baclofen (Lioresal), a lipophilic analogue of c-aminobutyric acid (GABA), and carisoprodol (Soma), a central nervous system depressant with an unknown mechanism of pharmacologic action, are categorized as muscle relaxants. Baclofen is used clinically in the management of spasticity and its sequelae secondary to severe chronic disorders such as multiple sclerosis and other types of spinal cord lesions. Carisoprodol is used for discomfort associated with acute and painful musculoskeletal conditions. Intoxication from these drugs occurs in both humans and animals necessitating a need for their detection in plasma/serum, tissue, and gastrointestinal contents samples. A sensitive and specific analytical method for detection and quantitation of these compounds using liquid chromatography with positive atmospheric pressure chemical ionization-mass spectrometry was developed. A rapid extraction procedure for both analytes from fortified bovine sera is described. Chromatographic separation was carried out on a C(18) reverse-phase column with a gradient elution of acetonitrile and 0.25% acetic acid. The effluent was directed to the mass spectrometer with fragmentation information for baclofen and carisoprodol obtained in a scan monitoring mode. Linear standard curves for baclofen and carisoprodol were constructed based on at least two corresponding extracted ions over a concentration range of 0.1-50 micro g/mL. The analysis of fortified sera samples demonstrates good accuracy and precision for the method with a limit of detection of 0.5 micro g/mL for carisoprodol (n = 3) and 1 micro g/mL for baclofen (n = 4) and a limit of quantitation of 2 micro g/mL for both compounds. Recoveries at the limit of quantitation were between 75 and 95% for both analytes, with a 4.8-9.3% range in standard deviation.

Animals↗