Publications by authors named "Dwayne E Schrunk"

7 Publications

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Variable accuracy, precision, and consistency of compounded famciclovir formulated for management of feline herpesvirus-1 in cats.

Vet Ophthalmol 2021 Jun 12. Epub 2021 Jun 12.

Department of Veterinary Clinical Sciences, College of Veterinary Medicine, Iowa State University, Ames, IA, USA.

Objective: To evaluate compounded famciclovir suspensions for accuracy, precision, and consistency in drug content.

Procedures: Two compounded famciclovir concentrations were evaluated (250 and 400 mg/mL, 30 preparations total from nine 503A compounding pharmacies) with U.S. Food and Drug Administration (FDA)-approved famciclovir tablets as control. Drug quantification via high-performance liquid chromatography (with famciclovir reference standard and pramipexole internal standard) was performed at 0, 14, and 28 days with concentrations of 90%-110% of labeled dose considered acceptable (US Pharmacopoeia standards).

Results: FDA-approved tablets from three different manufacturers were found to be accurate and precise with acceptable drug content. A significantly greater mean deviation from labeled content was noted for 400 mg/mL suspensions (-52.9%) compared to 250 mg/mL suspensions (-18.0%). When assessing time points separately, 15/63 (24%) samples of 250 mg/mL and 0/27 (0%) samples of 400 mg/mL suspensions met the acceptance standards. Coefficients of variation (CV) in drug content among pharmacy batches ranged from 0.5% to 29%, with 5/10 formulations having significantly lower CV% compared to control (decreased precision). Similarly, drug content changed over time (0-28 days) in all compounded formulations, with both downward and upward trends observed (variable consistency).

Conclusions: Most compounded famciclovir formulations were inaccurate, imprecise, and inconsistent. FDA-approved famciclovir tablets may be preferred over compounded famciclovir formulations for the management of feline herpesvirus-1. If compounded famciclovir is used in practice, a concentration of 250 mg/mL is preferred over 400 mg/mL given the lower accuracy of the higher concentration.
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http://dx.doi.org/10.1111/vop.12910DOI Listing
June 2021

High-performance liquid chromatography and Enzyme-Linked Immunosorbent Assay techniques for detection and quantification of aflatoxin B in feed samples: a comparative study.

BMC Res Notes 2019 Aug 7;12(1):492. Epub 2019 Aug 7.

College of Veterinary Medicine, Iowa State University, Ames, IA, USA.

Objective: Comparison was done between high-performance liquid chromatography (HPLC) and a competitive enzyme-linked immunosorbent assay (ELISA) for detection and quantification of aflatoxin B (AFB) in feed samples. The two procedures were standardized and validated before the actual experiment. Five concentrations (0, 5, 10, 20 and 30 ppb) of feed samples were used for both methods. For the HPLC technique, the samples were extracted in acetonitrile/water (90/10) solution, cleaned-up using solid phase extraction (SPE) column, and derivatized by water/trifluoroacetic acid/glacial acetic acid (35/10/5) solution before instrument analysis. The samples were extracted in 70% methanol for the ELISA technique.

Results: The two tests showed very strong linearity with correlation coefficient value of > 0.99 using standard solutions. The mean recovery rate was 92.42% (with relative standard deviation (RSD) of 5.97) and 75.64% (RSD = 34.88) for HPLC and ELISA, respectively. There was no statistically significant difference in recovery rate between the two methods. There was a positive correlation (r = 0.84) between them which indicated that the two techniques can be used to detect and quantify aflatoxin B in feed samples. However, there were variations among replicates for the ELISA method, which shows that this method is more applicable for screening purposes.
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http://dx.doi.org/10.1186/s13104-019-4538-zDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6686514PMC
August 2019

Evaluation of a Diagnostic Method to Quantify Aflatoxins B and M in Animal Liver by High-Performance Liquid Chromatography with Fluorescence Detection.

J AOAC Int 2019 Sep 8;102(5):1530-1534. Epub 2019 Feb 8.

Iowa State University, Department of Veterinary Diagnostic and Production Animal Medicine, Veterinary Diagnostic Laboratory, 1850 Christensen Dr, Ames, IA 50011-1134.

Aflatoxins (AFs) are secondary metabolites of fungi and are one of the causes of toxin-related pet food recalls. An intralaboratory method was previously developed to quantify aflatoxin B (AFB) and aflatoxin M (AFM) in animal liver by HPLC with fluorescence detection. The aim of this study was to extensively evaluate the method performance with a single-laboratory blinded method test (BMT-S) and a multilaboratory blinded method test (BMT-M). Blinded tissue samples were prepared by a third-party laboratory and sent out to participating laboratories for both BMT-S and BMT-M. In both tests, participants analyzed blinded samples prepared by an independent laboratory. In the BMT-S, accuracy ranged between 111 and 154% for AFB and 113 and 159% for AFM within the quantitation range of 0.1-0.5 ng/g. The HorRat values for repeatability ranged between 0.1 and 0.3 for AFB and 0.3 and 0.6 for AFM. In the BMT-M, the interlaboratory accuracy ranged between 77 and 81% for AFB and 83 and 85% for AFM within the quantitation range of 0.2-10 ng/g. The HorRat values for reproducibility ranged between 0.4 and 0.7 for AFB and 0.4 and 0.9 for AFM. Both recovery and reproducibility were acceptable. BMT-M evaluation demonstrated that the method was suitable for quantitation of aflatoxins B and M in animal liver between laboratories. The BMT-S and BMT-M results demonstrated that the method is rugged and reproducible among the participating laboratories.
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http://dx.doi.org/10.5740/jaoacint.18-0355DOI Listing
September 2019

Intra-laboratory Development and Evaluation of a Quantitative Method for Measurement of Aflatoxins B1, M1 and Q1 in Animal Urine by High Performance Liquid Chromatography with Fluorescence Detection.

J Anal Toxicol 2017 Oct;41(8):698-707

Veterinary Diagnostic Laboratory, Department of Veterinary Diagnostic and Production Animal Medicine, Iowa State University, 1850 Christensen Drive, Ames, IA 50011-1134, USA.

Mycotoxins negatively impact animal health. Aflatoxins (AFs) are the most common mycotoxins affecting both large and small animals and are a common cause of toxin-related pet food recalls. Definitive diagnosis of aflatoxicosis is constrained by a lack of validated ante-mortem analytical methods for detection and quantitation of AFs and their metabolites in biological specimens. Herein, we developed and evaluated a urine-based quantitative method for measurement of aflatoxin B1 (AFB1) and its metabolites aflatoxin M1 (AFM1) and aflatoxin Q1 (AFQ1) in animal urine. (Some of the results have been presented at 59th AAVLD conference, Greensboro, North Carolina, October 13-19th, 2016.) This method uses an immuno-affinity column for clean-up and pre-column derivatization followed by high performance liquid chromatography analysis with fluorescence detection. The method has high selectivity, recovery (>81%) and sensitivity with an instrument limit of detection of 0.20-1.02 pg; instrument limit of quantitation of 0.77-4.46 pg; and a method lower limit of quantitation of 0.30-2.5 ng/mL. The method has high accuracy, repeatability, and is rugged against minor changes. However, because of poor sensitivity of AFQ1 at low concentrations we recommend this method for quantitative determination of AFB1 and AFM1, and for qualitative measurement of AFQ1 in animal urine for diagnosis of aflatoxicosis.
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http://dx.doi.org/10.1093/jat/bkx059DOI Listing
October 2017

Intralaboratory development and evaluation of a high-performance liquid chromatography-fluorescence method for detection and quantitation of aflatoxins M1, B1, B2, G1, and G2 in animal liver.

J Vet Diagn Invest 2016 Nov 16;28(6):646-655. Epub 2016 Sep 16.

Veterinary Diagnostic Laboratory, Department of Veterinary Diagnostic and Production Animal Medicine, Iowa State University, Ames, IA

Aflatoxins are potent mycotoxins with effects that include hepatotoxicity, immunosuppression, and suppression of animal growth and production. The etiologic diagnosis of aflatoxicosis, which is largely based on analysis of contaminated feed matrices, has significant disadvantages given the fact that representative feed samples may not be available and feed-based test methods are not confirmatory of an etiologic diagnosis. A tissue-based analytical method for biomarkers of exposure would be valuable for confirmation of aflatoxicosis. We describe in-house development and evaluation of a high-performance liquid chromatographic method with fluorescence detection and precolumn derivatization for determination of aflatoxins M, B, B, G, and G in animal liver. The method demonstrates good selectivity for the tested aflatoxins in the liver matrix. The overall range was 0.03-0.10 ng/g for limit of detection and 0.09-0.18 ng/g for limit of quantitation. The correlation coefficient (R) of calibration curves was >0.9978 for AFM, 0.9995 for AFB, 0.9986 for AFB, 0.9983 for AFG, and 0.9980 for AFG For fortification levels of 0.2-10 ng/g, repeatability was 10-18% for AFM, 7-14% for AFB, 5-14% for AFB, 6-16% for AFG, and 10-15% for AFG Recovery was 52-57% for AFM, 54-62% for AFB, 55-61% for AFB, 57-67% for AFG, and 61-65% for AFG There was no liver matrix effect found. The method is rugged against minor changes based on the selected factors. The results indicate that the proposed method is suitable for quantitative determination of aflatoxins M, B, B, G, and G in liver.
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http://dx.doi.org/10.1177/1040638716668217DOI Listing
November 2016

A novel orellanine containing mushroom Cortinarius armillatus.

Toxicon 2016 May 23;114:65-74. Epub 2016 Feb 23.

Department of Veterinary Diagnostic and Production Animal Medicine, Iowa State University, 50011, Ames, IA, USA. Electronic address:

Orellanine (3,3',4,4'-tetrahydroxy-2,2'-bipyridine-1,1'-dioxide) is a tetrahydroxylated di-N-oxidized bipyridine compound. The toxin, present in certain species of Cortinarius mushrooms, is structurally similar to herbicides Paraquat and Diquat. Cortinarius orellanus and Cortinarius rubellus are the major orellanine-containing mushrooms. Cortinarius mushrooms are widely reported in Europe where they have caused human poisoning and deaths through accidental ingestion of the poisonous species mistaken for the edible ones. In North America, Cortinarius orellanosus mushroom poisoning was recently reported to cause renal failure in a Michigan patient. Cortinarius mushroom poisoning is characterized by delayed acute renal failure, with some cases progressing to end-stage kidney disease. There is debate whether other Cortinarius mushroom contain orellanine or not, especially in North America. Currently, there are no veterinary diagnostic laboratories in North America with established test methods for detection and quantitation of orellanine. We have developed two diagnostic test methods based on HPLC and LC-MSMS for identification and quantitation of orellanine in mushrooms. Using these methods, we have identified Cortinarius armillatus as a novel orellanine-containing mushroom in North America. The mean toxin concentration of 145 ug/g was <1% of that of the more toxic C. rubellus. The HPLC method can detect orellanine at 17 μg g(-1) while the LC-MSMS method is almost 2000 times more sensitive and can detect orellanine at 30 ng g(-1). Both tests are quantitative, selective and are now available for veterinary diagnostic applications.
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http://dx.doi.org/10.1016/j.toxicon.2016.02.010DOI Listing
May 2016

Ergot alkaloid intoxication in perennial ryegrass (Lolium perenne): an emerging animal health concern in Ireland?

Ir Vet J 2014 25;67(1):21. Epub 2014 Sep 25.

Centre for Veterinary Epidemiology and Risk Analysis (CVERA), Veterinary Sciences Centre, University College Dublin, Belfield, Dublin 4, Ireland.

Four primary mycotoxicosis have been reported in livestock caused by fungal infections of grasses or cereals by members of the Clavicipitaceae family. Ergotism (generally associated with grasses, rye, triticale and other grains) and fescue toxicosis (associated with tall fescue grass, Festuca arundinacea) are both caused by ergot alkaloids, and referred to as 'ergot alkaloid intoxication'. Ryegrass staggers (associated with perennial ryegrass Lolium perenne) is due to intoxication with an indole-diperpene, Lolitrem B, and metabolites. Fescue-associated oedema, recently described in Australia, may be associated with a pyrrolizidine alkaloid, N-acetyl norloline. Ergotism, caused by the fungus Claviceps purpurea, is visible and infects the outside of the plant seed. Fescue toxicosis and ryegrass staggers are caused by Neotyphodium coenophalium and N. lolii, respectively. Fescue-associated oedema has been associated with tall fescue varieties infected with a specific strain of N. coenophialum (AR542, Max P or Max Q). The name Neotyphodium refers to asexual derivatives of Epichloë spp., which have collectively been termed the epichloë fungi. These fungi exist symbiotically within the grass and are invisible to the naked eye. The primary toxicological effect of ergot alkaloid involves vasoconstriction and/or hypoprolactinaemia. Ingestion of ergot alkaloid by livestock can cause a range of effects, including poor weight gain, reduced fertility, hyperthermia, convulsions, gangrene of the extremities, and death. To date there are no published reports, either internationally or nationally, reporting ergot alkaloid intoxication specifically associated with perennial ryegrass endophytes. However, unpublished reports from the Irish Equine Centre have identified a potential emerging problem of ergot alkaloid intoxication with respect to equines and bovines, on primarily perennial ryegrass-based diets. Ergovaline has been isolated in varying concentrations in the herbage of a small number of equine and bovine farms where poor animal health and performance had been reported. Additionally, in some circumstances changes to the diet, where animals were fed primarily herbage, were sufficient to reverse adverse effects. Pending additional information, these results suggest that Irish farm advisors and veterinarians should be aware of the potential adverse role on animal health and performance of ergot alkaloids from perennial ryegrass infected with endophytic fungi.
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http://dx.doi.org/10.1186/2046-0481-67-21DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4186922PMC
October 2014
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