Karyn Bischoff

Clinicopathologic, histologic, and toxicologic findings in 70 cats inadvertently exposed to pet food contaminated with melamine and cyanuric acid

OBJECTIVE To document clinicopathologic, histologic, and toxicologic findings in cats inadvertently exposed to pet food contaminated with melamine and cyanuric acid. DESIGN Case series. ANIMALS 70 cats from a single cattery inadvertently fed contaminated food that was the subject of a March 2007 recall. PROCEDURES Clinical signs, clinicopathologic and histopathologic findings, and results of toxicologic analyses were recorded. RESULTS Clinical signs were identified in 43 cats and included inappetence, vomiting, polyuria, polydipsia, and lethargy. Azotemia was documented in 38 of the 68 cats for which serum biochemical analyses were performed 7 to 11 days after consumption of the contaminated food. One cat died, and 13 were euthanized. Histologic examination of kidney specimens from 13 cats revealed intratubular crystalluria, tubular necrosis with regeneration, and subcapsular perivascular inflammation characterized by perivascular fibroplasia or fibrosis and inflammation with intravascular fibrin thrombi. Toxicologic analyses revealed melamine and cyanuric acid in samples of cat food, vomitus, urine, and kidneys. CONCLUSIONS AND CLINICAL RELEVANCE In cats unintentionally fed pet food contaminated with melamine and cyanuric acid, the most consistent clinical and pathologic abnormalities were associated with the urinary tract, specifically tubular necrosis and crystalluria.

Clinical and clinicopathologic features of dogs that consumed foodborne hepatotoxic aflatoxins: 72 cases (2005–2006)

OBJECTIVE To characterize clinical signs, clinicopathologic features, treatments, and survival in dogs with naturally acquired foodborne aflatoxicosis. DESIGN Retrospective case series. ANIMALS 72 dogs that consumed aflatoxin-contaminated commercial dog food. PROCEDURES Medical records of affected dogs were reviewed. Between December 2005 and March 2006, dogs were identified as having foodborne aflatoxin hepatotoxicosis on the basis of the history of consumption of contaminated food or characteristic histopathologic lesions (subject dog or a recently deceased dog in the same household or kennel). Recorded information included signalment, clinical features, clinicopathologic test results, treatments, and survival. Data were analyzed by survival status. RESULTS Most dogs were of large breeds from breeding kennels. No significant differences were found in age or weight between 26 (36%) survivor dogs and 46 (64%) nonsurvivor dogs. Severity of clinical signs varied widely; 7 dogs died abruptly. In order of onset, clinical features included anorexia, lethargy, vomiting, jaundice, diarrhea (melena, hematochezia), abdominal effusion, peripheral edema, and terminal encephalopathy and hemorrhagic diathesis. Common clinicopathologic features included coagulopathic and electrolyte disturbances, hypoproteinemia, increased serum liver enzyme activities, hyperbilirubinemia, and hypocholesterolemia. Cytologic hepatocellular lipid vacuolation was confirmed in 11 dogs examined. In comparisons of clinicopathologic test results between survivor and nonsurvivor dogs, only granular cylindruria (7/21 dogs) consistently predicted death. Best early markers of aflatoxicosis were low plasma activities of anticoagulant proteins (protein C, antithrombin) and hypocholesterolemia. Despite aggressive treatment, many but not all severely affected dogs died. CONCLUSIONS AND CLINICAL RELEVANCE Serum liver enzyme activities and bilirubin concentration were unreliable early markers of aflatoxin hepatotoxicosis in dogs. Hypocholesterolemia and decreased plasma protein C and antithrombin activities may function as exposure biomarkers.

Identification of protoxins and a microbial basis for red maple (Acer rubrum) toxicosis in equines

The leaves of Acer rubrum (red maple), especially when wilted in the fall, cause severe oxidative damage to equine erythrocytes, leading to potentially fatal methemoglobinemia and hemolytic anemia. Gallic acid and tannins from A. rubrum leaves have been implicated as the toxic compounds responsible for red maple toxicosis, but the mechanism of action and toxic principle(s) have not been elucidated to date. In order to investigate further how red maple toxicosis occurs, aqueous solutions of gallic acid, tannic acid, and ground dried A. rubrum leaves were incubated with contents of equine ileum, jejunum, cecum, colon, and liver, and then analyzed for the metabolite pyrogallol, as pyrogallol is a more potent oxidizing agent. Gallic acid was observed to be metabolized to pyrogallol maximally in equine ileum contents in the first 24 hr. Incubation of tannic acid and A. rubrum leaves, individually with ileum contents, produced gallic acid and, subsequently, pyrogallol. Ileum suspensions, when passed through a filter to exclude microbes but not enzymes, formed no pyrogallol, suggesting a microbial basis to the pathway. Bacteria isolated from ileum capable of pyrogallol formation were identified as Klebsiella pneumoniae and Enterobacter cloacae. Therefore, gallotannins and free gallic acid are present in A. rubrum leaves and can be metabolized by K. pneumoniae and E. cloacae found in the equine ileum to form pyrogallol either directly or through a gallic acid intermediate (gallotannins). Identification of these compounds and their physiological effects is necessary for the development of effective treatments for red maple toxicosis in equines.

Animals as Sentinels for Human Lead Exposure: A Case Report

Because human and nonhuman animals often share the same environment, there is potential concurrent exposure to toxicants. As a result, domestic animals can be used as sentinels for exposure of people to these agents. Here we present a case illustrating exposure of both humans and domestic animals to lead contamination in their environments. This case study occurred at a farm where cattle deaths were determined to have been caused by lead poisoning based on elevated postmortem tissue lead concentrations. Elevated blood lead concentrations were detected in the remaining cattle, a dog, a cat, and a pregnant woman (37.3 µg/dL) living on the farm. The range of blood lead concentrations in the domestic animals was 8.42 (cat) to 85.41 µg/dL (calf), although clinical signs of lead poisoning were not apparent in these animals. Further testing revealed the most likely source for lead exposure to be paint in the barn and home. Household dogs and cats have been used as sentinels for lead poisoning in humans, but cattle may also act as a sentinel species for environmental lead contamination.

The effects of formalin fixation and tissue embedding of bovine liver on copper, iron, and zinc analysis

Veterinary analytical chemistry laboratories might be called upon to analyze formalin-fixed or paraffin-embedded tissue samples for trace minerals. The purpose of this study was to determine whether concentrations of copper (Cu), iron (Fe), and zinc (Zn) are comparable among fresh or frozen, formalin-fixed, and paraffin-embedded bovine liver samples on an as-received basis. Three liver sample subtypes (fresh or frozen, formalin-fixed, and paraffin-embedded) from 12 cows were collected and analyzed for Cu, Fe, and Zn concentrations. Concentrations were measured by using inductively coupled argon plasma atomic-emission spectroscopy. There was no significant difference in mineral measurements between fresh or frozen and formalin-fixed samples for Cu and Zn (both P ≥ 0.052). The median concentration of Fe was lower in the fresh or frozen samples than in the formalin-fixed samples. However, for every pair of fresh or frozen and paraffin-embedded samples for all 3 minerals, the fresh or frozen sample had a lower measurement than the paraffin-embedded sample (all P = 0.005). Differences in mineral measurements associated with tissue processing did not result in differences in classification (within or outside the reference range) for Fe. However, the classification of Cu and Zn was different up to 25% of the time with fresh or frozen versus formalin-fixed or embedded liver. Although Cu, Fe, and Zn concentrations attained from processed tissue may be useful, they must be evaluated with caution.

Development of a monoclonal antibody against deoxynivalenol for magnetic nanoparticle-based extraction and an enzyme-linked immunosorbent assay

Monoclonal antibody (mAb, NVRQS-DON) against deoxynivalenol (DON) was prepared. DON-Ag coated enzyme linked immunosorbent assay (ELISA) and DON-Ab coated ELISA were prepared by coating the DON-BSA and DON mAb. Quantitative DON calculation ranged from 50 to 4,000 ng/mL for DON-Ab coated ELISA and from 25 to 500 ng/mL for DON-Ag coated ELISA. 50% of inhibitory concentration values of DON, HT-2, 15-acetyl-DON, and nivalenol were 23.44, 22,545, 5,518 and 5,976 ng/mL based on the DON-Ab coated ELISA. Cross-reactivity levels of the mAb to HT-2, 15-acetyl-DON, and nivalenol were 0.1, 0.42, and 0.40%. The intra- and interassay precision coefficient variation (CV) were both <10%. In the mAb-coated ELISA, mean DON recovery rates in animal feed (0 to 1,000 µg/kg) ranged from 68.34 to 95.49% (CV; 4.10 to 13.38%). DON in a buffer solution (250, 500 and 1,000 ng/mL) was isolated using 300 µg of NVRQS-DON and 3 mg of magnetic nanoparticles (MNPs). The mean recovery rates of DON using this mAb-MNP system were 75.2, 96.9, and 88.1% in a buffer solution spiked with DON (250, 500, and 1,000 ng/mL). Conclusively we developed competitive ELISAs for detecting DON in animal feed and created a new tool for DON extraction using mAb-coupled MNPs.

Pet Food Recalls and Pet Food Contaminants in Small Animals

Most pet foods are safe, but incidents of chemical contamination occur and lead to illness and recalls. There were 11 major pet food recalls in the United States between 1996 and 2010 that were due to chemical contaminants or misformulations: 3 aflatoxin, 3 excess vitamin D3, 1 excess methionine, 3 inadequate thiamine, and 1 adulteration with melamine and related compounds and an additional 2 warnings concerning a Fanconilike renal syndrome in dogs after ingesting large amounts of chicken jerky treat products. This article describes clinical findings and treatment of animals exposed to the most common pet food contaminants.

Time-dependent changes in lead and δ-aminolevulinic acid after subchronic lead exposure in rats

The time-dependent changes in lead (Pb) concentrations in major tissues, serum and urine, and the Pb biomarker δ-aminolevulinic acid (ALA) concentration in urine were studied in rats after sub-chronic Pb exposure. Female Sprague-Dawley (SD) rats were exposed to Pb in drinking water at concentrations of 100 ppm and 1000 ppm for 30 days. The Pb concentration in muscle, liver, kidney, plasma and urine, and the ALA concentration in urine were determined during exposure and every 7 days after exposure for 3 weeks. The muscle Pb concentration did not change post exposure. The liver Pb concentration increased 2.2 to 2.8 times (100 ppm group) and 3.9 to 7.4 times (1000 ppm group) during exposure, then decreased rapidly. Kidney Pb concentrations were 8.0 to 14.3 times (100 ppm group) and 13.8 to 28.5 times (1000 ppm group) higher than controls during exposure and decreased for 1 to 2 weeks post exposure. Plasma Pb concentrations were 1.2 to 3.3 times (100 ppm group) and 2.9 to 5.8 times (1000 ppm group) higher than control concentrations during exposure and decreased time-dependently in the 1000-ppm group after exposure. Urine Pb concentrations were 8.5 to 10.7 times (100 ppm group) and 30.4 to 51.1 times (1000 ppm group) higher than control concentrations during exposure and rapidly decreased after exposure, though concentrations remained up to 4 times higher than controls in the 1000 ppm exposure group. Urine ALA concentrations increased 1.7 to 2.6 and 7.1 to 32.7 times during exposure in the 100 ppm and 1000 ppm groups respectively, and remained elevated for 21 days post exposure. Our data support that urine Pb concentration is a useful marker for acute Pb exposure or post exposure. Urine ALA may be a predicator of biological response to Pb exposure.

Identification and Initial Characterization of an Adenovirus Associated With Fatal Hepatic and Lymphoid Necrosis in a Meyer's Parrot (Poicephalus meyeri)

Abstract A juvenile Meyers parrot (Poicephalus meyeri) was presented for acute depression and crop stasis and died. On histopathologic examination, intranuclear inclusion bodies were seen in the liver, spleen, proventriculus, and intestinal mucosa. DNA in situ hybridization of tissues was positive for adenovirus and negative for herpesvirus, polyomavirus, and circovirus. Degenerate (polymerase chain reaction [PCR]) primers targeting a conserved region of adenovirus DNA–dependent DNA polymerase were used to amplify and sequence a product from paraffin-embedded tissue. This is the first sequence information available for a psittacine adenovirus. Phylogenetic and comparative sequence analysis indicated that this virus is a member of the genus Aviadenovirus and is here termed Meyers parrot adenovirus 1. Consensus nested PCR and sequencing can be used to rapidly identify novel adenoviruses, and DNA in situ hybridization may be used for rapid localization of novel viruses in tissues. Identification of adenoviral types and species will provide useful diagnostic, prognostic, and epidemiologic information for clinicians.

Production of a highly group-specific monoclonal antibody against zearalenone and its application in an enzyme-linked immunosorbent assay.

A monoclonal antibody (mAb) against zearalenone (ZEN) was produced using ZEN-carboxymethoxylamine and -BSA conjugates. Antibody produced by one clone showing a very high binding ability was selected and found to have a higher affinity for ZEN compared to a commerciall ZEN antibody. We developed two direct competitive ELISA systems using the selected antibody (ZEN-coated and anti-ZEN antibody-coated ELISA). Quantitative ranges for the anti-ZEN antibody-coated ELISA and ZEN-coated ELISA were from 25 to 750 ppb and from 12.5 to 100 ppb, respectively. The detection limit of both methods as measured with standard solutions was 10 ppb. The intra-plate and inter-well variation of both ELISAs were less than 10%. The IC50 values for α-zearalenol, β-zearalenol, α-zearalanol, and β-zearalanol compared to ZEN were 108.1, 119.3, 114.1, and 130.3% for the ZEN-coated ELISA. These values were 100.7, 120.7, 121.6, and 151.6% for the anti-ZEN antibody-coated ELISA. According to the anti-ZEN antibody-coated ELISA, the average recovery rates of ZEN from spiked animal feed containing 150 to 600 ng/mL of ZEN ranged from 106.07 to 123.00% with 0.93 to 2.28% coefficients of variation. Our results demonstrate that the mAb developed in this study could be used to simultaneously screen for ZEN and its metabolites in feed.