High-concentration buprenorphine exceeds target plasma concentrations for extended periods following subcutaneous administration in American flamingos (Phoenicopterus ruber)

OBJECTIVE

To determine the pharmacokinetic parameters of a high-concentration buprenorphine formulation after a single SC dose in American flamingos (Phoenicopterus ruber).

ANIMALS

6 healthy adult American flamingos (3 males and 3 females).

METHODS

A single dose of high-concentration buprenorphine (1.8 mg/kg) was administered SC to all birds. Blood samples were collected at 0.25, 0.5, 1, 2, 4, 8, 12, 24, 48, 72, and 96 hours after drug administration between October 14 and October 18, 2022. Plasma buprenorphine concentrations were determined by liquid chromatography-tandem mass spectrometry and a noncompartmental analysis was used to determine pharmacokinetic parameters.

RESULTS

Mean ± SD peak plasma drug concentration (Cmax) was 195.1 ± 187.4 ng/mL, the mean time to peak plasma concentration (Tmax) was 0.32 ± 0.31 hours, the mean area under the concentration-vs-time curve from time 0 to the last measured concentration (AUC0-last) was 881.4 ± 205.4 ng/mL, and mean terminal half-life (t1/2) was 12.6 ± 3.86 hours. Mean plasma buprenorphine concentrations were >1 ng/mL for at least 48 hours after drug administration. No clinically significant adverse effects were observed.

CLINICAL RELEVANCE

High-concentration buprenorphine dosed at 1.8 mg/kg SC in American flamingos rapidly exceeded plasma drug concentrations reported to have analgesic effects in other avian species and maintained these levels for extended periods. Sedative effects were similar to those reported for other species. Additional studies are needed to evaluate the clinical efficacy of high-concentration buprenorphine at this dose in American flamingos.

Pharmacokinetics of mavacoxib in New Zealand White rabbits (Oryctolagus cuniculus)

OBJECTIVES

To characterize the pharmacokinetics of a single oral dose (6 mg/kg) of mavacoxib in New Zealand White rabbits (Oryctolagus cuniculus) and to characterize any clinicopathologic effects with this medication and dose.

ANIMALS

Six healthy, 4-month-old New Zealand White rabbits (3 male, 3 female).

PROCEDURES

Before drug administration, clinicopathologic samples were collected for baseline data (CBC, serum biochemical analyses, and urinalysis including urine protein-to-creatinine ratio). All 6 rabbits received a single oral dose (6 mg/kg) of mavacoxib. Clinicopathologic samples were collected at set time intervals to compare with the baseline. Plasma mavacoxib concentrations were determined using liquid chromatography with mass spectrometry, and pharmacokinetic analysis was performed using non-compartmental methods.

RESULTS

After a single oral dose, the maximum plasma concentration (Cmax; mean, range) was 854 (713-1040) ng/mL, the time to Cmax (tmax) was 0.36 (0.17-0.50) days, the area under the curve from 0 to the last measured time point (AUC0-last) was 2000 (1765-2307) days*ng/mL, the terminal half-life (t1/2) was 1.63 (1.30-2.26) days, and the terminal rate constant (λz) was 0.42 (0.31-0.53) days. All results for CBCs, serum biochemical analyses, urinalyses, and urine protein-to-creatinine ratios remained within published normal reference intervals.

CLINICAL RELEVANCE

This study determined that plasma concentrations reached target levels of 400 ng/mL for 48 hours in 3/6 rabbits at 6 mg/kg PO. In the remaining 3/6 rabbits, the plasma concentrations were 343-389 ng/mL at 48 hours, which is below the target concentration. Further research is needed to make a dosing recommendation, including a pharmacodynamic study and investigating pharmacokinetics at different doses and multiple doses.

Feeding decreases the oral bioavailability of cannabidiol and cannabidiolic acid in hemp oil in New Zealand White rabbits (Oryctolagus cuniculus)

OBJECTIVE

To determine the pharmacokinetics of a solution containing cannabidiol (CBD) and cannabidiolic acid (CBDA), administered orally in 2 single-dose studies (with and without food), in the domestic rabbit (Oryctolagus cuniculus).

ANIMALS

6 healthy New Zealand White rabbits.

PROCEDURES

In phase 1, 6 rabbits were administered 15 mg/kg CBD with 16.4 mg/kg CBDA orally in hemp oil. In phase 2, 6 rabbits were administered the same dose orally in hemp oil followed by a food slurry. Blood samples were collected for 24 hours to determine the pharmacokinetics of CBD and CBDA. Quantification of plasma CBD and CBDA concentrations was determined using a validated liquid chromatography-mass spectrometry (LC-MS) assay. Pharmacokinetics were determined using noncompartmental analysis.

RESULTS

For CBD, the area under the curve extrapolated to infinity (AUC)0-∞ was 179.8 and 102 hours X ng/mL, the maximum plasma concentration (Cmax) was 30.4 and 15 ng/mL, the time to Cmax (tmax) was 3.78 and 3.25 hours, and the terminal half-life (t1/2λ) was 7.12 and 3.8 hours in phase 1 and phase 2, respectively. For CBDA, the AUC0-∞ was 12,286 and 6,176 hours X ng/mL, Cmax was 2,573 and 1,196 ng/mL, tmax was 1.07 and 1.12 hours, and t1/2λ was 3.26 and 3.49 hours in phase 1 and phase 2, respectively. Adverse effects were not observed in any rabbit.

CLINICAL RELEVANCE

CBD and CBDA reached a greater Cmax and had a longer t1/2λ in phase 1 (without food) compared with phase 2 (with food). CBDA reached a greater Cmax but had a shorter t1/2λ than CBD both in phase 1 and phase 2. These data may be useful in determining appropriate dosing of cannabinoids in the domestic rabbit.

Pilot Study of a Single Dose of Orally Administered Tapentadol Suspension in Hispaniolan Amazon Parrots (Amazona ventralis)

Tapentadol is an analgesic agent that acts as both a µ-opioid receptor agonist and a norepinephrine reuptake inhibitor. It is a common therapeutic agent in human medicine for management of acute and chronic pain, and it is currently being investigated for use in veterinary medicine. Tapentadol was evaluated in Hispaniolan Amazon parrots (Amazona ventralis) because there is only 1 other oral opioid-like analgesic agent, tramadol, which has been evaluated in an avian species. The effectiveness of tramadol after administration to a patient involves a complex physiologic metabolism and has been found to have variable pharmacokinetics between species. Because of the lack of active metabolites from tapentadol, less interspecific variation was expected. Seven Hispaniolan Amazon parrots were used to evaluate the pharmacokinetics of tapentadol after a single 30 mg/kg PO administration of a compounded 5 mg/mL tapentadol suspension. Blood samples were collected before (time 0) and 0.25, 0.5, 0.75, 1, 1.5, 3, and 6 hours after administration, following a balanced, incomplete-block design. Plasma tapentadol concentrations were measured by high-pressure liquid chromatography with mass spectrometry. Results revealed detectable plasma concentrations in only 2 of 7 birds (29%), and the bird with the highest plasma levels had a peak concentration (C_max) of 143 ng/mL and a half-life (T _1/2) of 24.8 minutes. The variable plasma concentrations and short half-life of this drug in Hispaniolan Amazon parrots suggests that this drug would be of limited clinical use in this species; however, it is possible that this drug will be more bioavailable in other avian species.

Surgical Management of an Intrathoracic Branchial Cyst in a Yellow-crested Cockatoo (Cacatua sulphurea)

A 40-year-old, female lesser crested cockatoo (Cacatua sulphurea) was presented with a complaint of hyporexia and sudden onset of sneezing and wheezing. Physical examination revealed mild stertorous inhalation, and the apex of the heart was palpable caudoventral to the distal tip of the sternum. Projection radiographic images showed a soft tissue mass displacing the heart and the thoracic portion of the trachea. A subsequent computed tomography series revealed a single, large, and predominantly encapsulated soft-tissue mass. The mass was contained within the cranial thoracic region and occupied most of the anatomic location of the thoracic portion of the clavicular air sac, extending around a portion of the trachea. A surgical exploratory procedure was performed, with a thoracic inlet thoracotomy, and the mass was found to be cystic and deeply attached to surrounding tissues at its caudal-most aspect. Complete excision was not possible, and the mass was drained and an incomplete resection was accomplished with approximately one-half of the cystic structure removed and submitted for histopathology. The mass was found to be benign, epithelial-lined, dense, fibrous connective tissue that would be consistent with a branchial cyst.

Mucoepidermoid Carcinoma in the Skull of an Orange-winged Amazon Parrot (Amazona amazonica)

A 33-year-old female intact orange-winged Amazon parrot (Amazona amazonica) presented for a slowly growing mass over the right eye. A computed tomography scan performed with and without intravenous contrast revealed a heterogeneous mixed soft tissue and mineral-dense mass with a small area of non-contrast-enhancing fluid density located between the orbits at the caudal aspect of the nasal passages, with associated lysis of the right caudal nasal passage and the right frontal bone. Following euthanasia, the mass was found to consist of soft tissue between the right eye and nostril over the right frontal bone. Lysis of the underlying bone resulted in a bony defect leading into the infraorbital sinus along the dorsorostral aspect of the right eye. Histopathology revealed an unencapsulated, poorly demarcated, highly cellular neoplasm composed of islands and trabeculae of neoplastic cells embedded in abundant loose fibrovascular stroma which completely obliterated the cortical bone and sinuses of the rostral skull and infiltrated the surrounding muscle and soft tissue. Histologically, the tumor was consistent with a high-grade mucoepidermoid carcinoma, characterized by the presence of epidermoid, intermediate, and mucous-producing cell types. No evidence of metastasis was identified. The tissue of origin was suspected to be salivary or nasal mucous glands, but was difficult to confirm due to distortion of normal tissue architecture as a result of the tumor. Although mucoepidermoid carcinomas are a common salivary gland tumor in human medicine, they are not well recognized in avian species, and no specific case reports exist describing this pathology in an Amazon parrot. Despite the lack of distinct salivary glands in most avian species, mucoepidermoid carcinomas can occur, can cause significant clinical disease, and should be included as a differential diagnosis for avian patients presenting with similar lesions.

Diversity and Abundance of Nonculicid Biting Flies (Diptera) In A Zoo Environment

The diversity of nonculicid biting flies was surveyed in Sunset Zoo, Manhattan, KS, by carbon dioxide-baited traps. A total of 8,399 nonculicid biting-fly females representing 32 species and 5 families were collected. Twenty-one biting midge (Ceratopogonidae: Culicoides) and 7 black fly (Simuliidae) species were collected, including new state records of 3 Culicoides and 1 simuliid. The species richness of Culicoides and Simuliidae within the zoo represents 72.4% and 41.2%, respectively, of the fauna known to occur in Kansas. Trap type significantly influenced (P < 0.05) collections of the 5 species analyzed, and trapping period affected 3 species. The diversity and abundance of nonculicid biting flies in the zoo as related to animal health and wellness is discussed.

Clinical, morphological, and molecular characterization of an undetermined Babesia species in a maned wolf (Chrysocyon brachyurus)

A possible novel Babesia species infection of a maned wolf (Chrysocyon brachyurus) was first reported in 2012. The current case details a confirmed report of a maned wolf with infection by an undetermined species of Babesia. As the mortality and morbidity of babesiosis is high, this may become a significant concern to captive maned wolves, which are considered a near-threatened species by the World Association of Zoos and Aquariums. The aim of this study is to report the clinical, morphological and molecular characterization of this Babesia species. A 2.5-year-old, intact female maned wolf was found laterally recumbent with pale mucous membranes and jaundice the morning of presentation. Hematological and serum biochemical data were consistent with babesiosis and showed a regenerative severe anemia, leukocytosis, thrombocytopenia, hyperbilirubinemia, azotemia, increased creatine phosphokinase and increase alanine aminotransferase. On blood film review, inclusion bodies were seen in the red blood cells with cytomorphological features that were most consistent with a small form Babesia species. A blood sample was sent for polymerase chain reaction (PCR) testing and multi-locus sequence analyses. These findings suggested a unique Babesia species that is most closely related to a Babesia species (Babesia sp. AJB-2006) that has been found to infect raccoons (Procyon lotor) in North America. Although the cytomorphological features of the piroplasms and the clinical presentation were similar in both the current and 2012 case, when comparing the 18S melt curve temperature of the two Babesia isolates, the peak temperature was different. Unfortunately, genetic material from the 2012 case was not available so comparison of multi-locus gene sequences could not be performed, excluding the possibility to definitively state if the Babesia spp. from both cases were distinct from each other. The maned wolf was treated with a whole blood transfusion, dexamethazone (0.28 mg/kg IM), azithromycin (10 mg/kg in NaCl SC), atavaquone (1.5 cc PO), and 2 imidocarb (6.6 mg/kg IM) injections, and clinically improved. These findings demonstrate the need to further characterize the molecular and epidemiological differences of the Babesia species in this case report and the Babesia species known to infect raccoons.

Harvesting Sugar From Nonflowering Plants: Implications of a Marked Sugar Bait on Honey Bee (Hymenoptera: Apidae) Whole Hive Health

Honey bees (Apis mellifera) are effective foragers for floral and extra-floral sources of sugars and as a result may easily be exposed to toxicants in the environment, such as pesticides. Toxic sugar baits (TSB) or insecticide-laced baits are designed for insect vector management but may be a danger to foraging honey bees and their hives. During a mosquito movement study at a zoological institution, nonflowering foliage surrounding the zoo was marked with sugar solution dyed with over the counter food-coloring. Mosquitoes and other insects foraged on the marked sugar and were collected within the zoo. Additionally, four of six honey bee hives within the zoo had workers that also foraged the dyed sugar and consequently colored approximately 57 kg of honey within the hives. This observation identifies a possibility route of toxicant accumulation within the hives from TSB and possible exposure may have whole hive health implications not previously described on an individual bee level.

Suspected Hepadnavirus Association with a Hepatocellular Carcinoma in a Black-Tailed Prairie Dog (Cynomys ludovicianus)

Hepatocellular carcinomas are the most commonly reported neoplasm of black-tailed prairie dogs (Cynomys ludovicianus). In several other closely related Sciuridae species, infection with species-specific hepadnaviruses is associated with the development of these tumours, but such a hepadnavirus has not yet been identified in any prairie dog species, although its presence has been hypothesized previously. An adult prairie dog was humanely destroyed due to progressive illness and the identification of a cranial abdominal mass that was determined on histopathology to be a hepatocellular carcinoma. Deep sequencing of the tumour tissue identified the presence of a hepadnavirus, similar in its genetic structure to woodchuck hepatitis virus. Electron microscopy showed the presence of viral particles similar in structure to other hepadnaviral particles. This report suggests that a hepadnavirus may be associated with the development of hepatocellular carcinomas in the prairie dog.

Shope Fibroma in the External Ear Canal of a Domestic Rabbit

A 5-y-old, intact, 2.5-kg female domestic rabbit was presented because of blood spatter on the wall of its cage and the toenails of its right hind limb. Physical examination revealed a red, gelatinous mass that spanned the width of the right vertical ear canal. Radiographic images revealed a soft-tissue opacity at the base of the right ear, which was superimposed over the tympanic bulla and extended to the pinna. A CT scan revealed that the soft-tissue mass was within the vertical and horizontal portions of the right external ear canal and extended to the level of the tympanic membrane, with no bony involvement. An incisional biopsy of the mass and subsequent histopathology revealed heterophilic inflammation with bacteria, necrosis, and no evidence of neoplasia. The patient died during anesthesia for removal of the mass at 1 mo after the initial presentation. Necropsy with histopathology of the mass was consistent with Shope fibroma virus in light of the presence of typical intracytoplasmic eosinophilic inclusions. Electron microscopy of paraffin-embedded tissue revealed electron-dense intracytoplasmic structures within neoplastic cells consistent with the diagnosis of Leporipoxvirus. To our knowledge, this report is the first description of Shope fibroma virus invading the external ear canal of a domestic rabbit. Given the results of this case, Shope fibroma should be considered in rabbits presenting with abnormal tissue in the ear canal.

Malignant Melanoma of the Syrinx and Liver in an African Grey Parrot ( Psittacus erithacus erithacus)

A 20-year-old, female African grey parrot ( Psittacus erithacus erithacus) was examined because of ataxia and weakness. Radiographs were unremarkable, and results of a complete blood cell count revealed leukocytosis and heterophilia. Because of poor response to therapy with meloxicam, doxycycline, and enrofloxacin; deteriorating condition; and poor prognosis, the parrot was euthanatized. Postmortem examination revealed 2 dark red nodules in the liver. No grossly visible mass was observed in the syrinx. Histologic examination of the liver and syrinx revealed similar foci of round, oval, and polygonal cells exhibiting severe pleomorphism, with poorly demarcated cytoplasmic borders and moderate amounts of eosinophilic cytoplasm containing brown to black granules (melanin). The mitotic index was 15. The presence of melanin pigment is consistent with a diagnosis of melanoma at both sites. The multifocal distribution and intravascular invasion indicate metastasis; however, the site of origin was unknown. To our knowledge, this is the first recorded case of melanoma in an avian syrinx.

Ophthalmic Diagnostic Tests and Ocular Findings in a Flock of Captive American Flamingos ( Phoenicopterus ruber ruber)

Seventeen adult captive American flamingos ( Phoenicopterus ruber ruber) (34 eyes) underwent a complete ocular examination, including assessment of menace response, pupillary light reflexes, dazzle reflex, palpebral and corneal reflexes, fluorescein staining, slit-lamp biomicroscopy, and direct ophthalmoscopy. Birds were randomly assigned to one of 2 groups for tear production and intraocular pressure measurements. Tear production was measured by modified Schirmer tear test I (n = 9 birds) or phenol red thread test (n = 8 birds), and intraocular pressure was measured indirectly by applanation (Tonopen-XL) (n = 9 birds) or rebound (TonoVet) (n = 8 birds) tonometry. Conjunctival swab samples were taken from one randomly selected eye of all 17 birds to identify surface ocular microbial flora via aerobic bacterial culture. Additionally, 3 of the 17 birds were anesthetized for bilateral B-mode ocular ultrasonography examination to obtain axial globe measurements. Results showed that the menace response and dazzle reflex were absent in all birds. Sixteen of the 17 birds were free of significant ocular disease; a small cataract and pigment on the anterior lens capsule were noted in one eye of one bird. Mean ± SD tear production was 12.3 ± 4.5 mm/min (range, 4-20 mm/min) for modified Schirmer tear test I and 24.2 ± 4.4 mm/15 s (range, 14-30 mm/15 s) for phenol red thread test. Modified Schirmer tear test I measurements were significantly lower than phenol red thread measurements (P < .001). Mean intraocular pressure was 16.1 ± 4.2 mm Hg (range, 7-22 mm Hg) for Tonopen and 9.5 ± 1.7 mm Hg (range, 7-13 mm Hg) for TonoVet. Tonopen measurements were significantly higher than TonoVet measurements (P < .001). An Enterococcus species (9/17 eyes; 53%) and a gram-positive coccus (7/17 eyes; 41%) were the bacteria most commonly isolated from conjunctival swab samples. Mean B-mode ultrasonographic globe measurements of 6 eyes (3 birds) were axial globe length, 13.8 ± 0.16 mm; anterior chamber depth, 1.75 ± 0.05 mm; lens thickness, 4.6 ± 0.06 mm; vitreous body depth, 6.95 ± 0.10 mm; and pecten dimensions, 5.1 ± 0.38 mm length, 2.2 ± 0.14 mm width. In summary, the prevalence of ocular lesions was low in this population of captive American flamingos. Results obtained from 2 types of tear and intraocular pressure measurement tests were significantly different, indicating that a single type of each diagnostic test should be consistently used. A modification of the standard Schirmer tear test or use of phenol red thread test is recommended due to the small flamingo eye.

Effects of lidocaine administration via continuous rate infusion on the minimum alveolar concentration of isoflurane in New Zealand White rabbits (Oryctolagus cuniculus)

OBJECTIVE

To evaluate the effect of a continuous rate infusion (CRI) of lidocaine on the minimum alveolar concentration (MAC) of isoflurane in rabbits.

ANIMALS

Five 12-month-old female New Zealand White rabbits (Oryctolagus cuniculus).

PROCEDURES

Rabbits were anesthetized with isoflurane. Baseline isoflurane MAC was determined by use of the tail clamp technique. A loading dose of lidocaine (2.0 mg/kg, IV) was administered followed by a CRI of lidocaine at 50 μg/kg/min. After 30 minutes, isoflurane MAC was determined. Another loading dose was administered, and the lidocaine CRI then was increased to 100 μg/kg/min. After 30 minutes, isoflurane MAC was determined again. Plasma samples were obtained for lidocaine analysis after each MAC determination.

RESULTS

Baseline isoflurane MAC was 2.09%, which was similar to previously reported values in this species. Lidocaine CRI at 50 and 100 μg/kg/min induced significant reductions in MAC. The 50 μg/kg/min CRI resulted in a mean plasma lidocaine concentration of 0.654 μg/mL and reduction of MAC by 10.5%. The 100 μg/kg/min CRI of lidocaine resulted in a mean plasma concentration of 1.578 μg/mL and reduction of MAC by 21.7%. Lidocaine also induced significant decreases in arterial blood pressure and heart rate. All cardiopulmonary variables were within reference ranges for rabbits anesthetized with inhalation anesthetics. No adverse effects were detected; all rabbits had an uncomplicated recovery from anesthesia.

CONCLUSIONS AND CLINICAL RELEVANCE

Lidocaine administered as a CRI at 50 and 100 μg/kg/min decreased isoflurane MAC in rabbits. The IV administration of lidocaine may be a useful adjunct in anesthesia of rabbits.

The ability to achieve meiotic maturation in the dog oocyte is linked to glycolysis and glutamine oxidation

We tested the hypothesis that meiotic competence of dog oocytes is tightly linked with donor follicle size and energy metabolism. Oocytes were recovered from small (<1 mm diameter, n = 327), medium (1-<2 mm, n = 292) or large (≥2 mm, n = 102) follicles, cultured for 0, 24, or 48 hr, and then assessed for glycolysis, glucose oxidation, pyruvate uptake, glutamine oxidation, and nuclear status. More oocytes (P < 0.05) from large follicles (37%) reached the metaphase-II (MII) stage than from the small group (11%), with the medium-sized class being intermediate (18%; P > 0.05). Glycolytic rate increased (P < 0.05) as oocytes progressed from the germinal vesicle (GV) to MII stage. After 48 hr of culture, oocytes completing nuclear maturation had higher (P < 0.05) glycolytic rates than those arrested at earlier stages. GV oocytes recovered from large follicle oocytes had higher (P < 0.05) metabolism than those from smaller counterparts at culture onset. MII oocytes from large follicles oxidized more (P < 0.05) glutamine than the same stage gametes recovered from smaller counterparts. In summary, larger-sized dog follicles contain a more metabolically active oocyte with a greater chance of achieving nuclear maturation in vitro. These findings demonstrate a significant role for energy metabolism in promoting dog oocyte maturation, information that will be useful for improving culture systems for rescuing intraovarian genetic material.

Diabetic ketoacidosis with concurrent pancreatitis, pancreatic β islet cell tumor, and adrenal disease in an obese ferret (Mustela putorius furo)

A 5.5-y-old spayed female ferret (Mustela putorius furo) with a history of adrenal disease, respiratory disease, and chronic obesity was evaluated for progressive lethargy and ataxia, diminished appetite, and possible polyuria and polydipsia. Physical examination revealed obesity, lethargy, tachypnea, dyspnea, a pendulous abdomen, significant weakness and ataxia of the hindlimbs, prolonged skin tenting, and mild tail-tip alopecia. Clinicopathologic analysis revealed severe hyperglycemia, azotemia, an increased anion gap, glucosuria, ketonuria, proteinuria, and hematuria. Abdominal ultrasonography showed hyperechoic hepatomegaly, bilateral adrenomegaly, splenic nodules, mild peritoneal effusion, and thickened and mildly hypoechoic limbs of the pancreas with surrounding hyperechoic mesentery. Fine-needle aspirates of the liver were highly suggestive of hepatic lipidosis. In light of a diagnosis of concurrent diabetic ketoacidosis and pancreatitis, the ferret was treated with fluid therapy, regular and long-acting insulin administration, and pain medication. However, electrolyte derangements, metabolic acidosis, dyspnea, and the clinical appearance of the ferret progressively worsened despite treatment, and euthanasia was elected. Necropsy revealed severe hepatic lipidosis, severe suppurative pancreatitis and vacuolar degeneration of pancreatic islet cells, a pancreatic β islet cell tumor, bilateral adrenal cortical adenomas, and myocardial fibrosis. To our knowledge, this case represents the first report of concurrent diabetes mellitus, pancreatitis, pancreatic β islet cell tumor (insulinoma), and adrenal disease in a domestic ferret. The simultaneous existence of 3 endocrine diseases, pancreatitis, and their associated complications is a unique and clinically challenging situation.

Development of a novel clinical biomarker assay to detect and quantify aggrecanase-generated aggrecan fragments in human synovial fluid, serum and urine

OBJECTIVE

Proteolytic degradation of aggrecan in articular cartilage is a hallmark feature of osteoarthritis (OA). The present study was aimed at developing a sensitive enzyme linked immunosorbent assay (ELISA) for the detection of aggrecanase-cleaved fragments of aggrecan in human serum and urine to facilitate the clinical development of aggrecanase inhibitors for OA.

METHODS

The BC3 monoclonal antibody that detects the ARGS neoepitope sequence in aggrecanase-cleaved aggrecan was engineered and optimized using complementarity determining region (CDR)-saturation mutagenesis to improve its binding affinity to the neoepitope. A sandwich ELISA (BC3-C2 ELISA) was developed using the optimized alpha-ARGS antibody (BC3-C2) as capture antibody and a commercially available antibody directed against the hyaluronic-acid binding region (HABR) of aggrecan as detection antibody. Aggrecanase-cleaved fragments of aggrecan present in in vitro digests, human cartilage explant culture supernatants and in human synovial fluid, serum and urine were detected and quantified using this ELISA.

RESULTS

The optimized antibody had a 4-log improvement in affinity for the ARGS containing peptide compared to the parental BC3 antibody, while maintaining the ability to not cross-react with a spanning peptide. The BC3-C2 ELISA demonstrated the ability to detect aggrecanase-cleaved aggrecan fragments in the native state, without the need for deglycosylation. This ELISA was able to measure aggrecanase-generated ARGS containing aggrecan fragments in human articular cartilage (HAC) explant cultures in the basal state (without cytokine stimulation). Treatment with an aggrecanase inhibitor resulted in a dose-dependent inhibition of ARGS neoepitope released into the culture supernatant. The ELISA assay also enabled the detection of ARGS containing fragments in human synovial fluid, serum and urine, suggesting its potential utility as a biomarker of aggrecanase activity.

CONCLUSIONS

We have developed a novel ELISA using an optimized ARGS antibody and have demonstrated for the first time, an ELISA-based measurement of aggrecan degradation products in human serum and urine. This assay has the potential to serve as a mechanistic drug activity biomarker in the clinic and is expected to significantly impact/accelerate the clinical development of aggrecanase inhibitors and other disease modifying drugs for OA.

Oral Squamous Cell Carcinoma in a Vietnamese Pot-Bellied Pig (Sus Scrofa)

An 18-year-old, neutered, male Vietnamese pot-bellied pig ( Sus scrofa) was treated for chronic, intermittent nasal discharge and sneezing. The animal was diagnosed with severe periodontal disease (grade IV), an oronasal fistula, and multiple tooth root abscesses via dental examination and computed tomography of the skull. Dentistry was performed, including multiple tooth extractions, and antibiotic therapy was initiated. Eighteen months later, the animal was evaluated for lethargy, anorexia, and a firm, 12 cm × 12 cm mass between the 2 rami of the mandible. Laboratory testing revealed moderate anemia, severe leukocytosis, and hyperglobulinemia. Skull radiographs indicated osteomyelitis of the mandible and soft-tissue swelling. A fine-needle aspirate and biopsy were taken, and results were consistent with squamous cell carcinoma. Treatment with piroxicam and antibiotics was initiated as needed to control signs of pain and secondary infection, respectively. Three months after diagnosis, the pig was euthanized due to cachexia and severe depression secondary to squamous cell carcinoma. On postmortem examination, the right mandibular area contained multiple, coalescing, irregular masses extending from the ramus rostrally to the mandibular canine teeth and ventrally within the intermandibular space, completely obliterating the normal anatomy. An open midshaft fracture was present on the right mandible. On histopathology, the masses were confirmed as locally invasive and destructive squamous cell carcinoma. No evidence of metastasis was noted in regional lymph nodes or in any of the distant sites evaluated.

Three cases of systemic atypical granulomatous disease in moluccan cockatoos (Cacatua moluccensis): a new syndrome

A 1.5-year-old male Moluccan cockatoo (Cacatua moluccensis) presented to Kansas State University Veterinary Medical Teaching Hospital with a 4-month history of lethargy and weakness. Hematologic and radiographic diagnostic testing revealed profound leukocytosis and coelomic and pulmonary granulomatous masses of unknown origin. The bird died during laparoscopic evaluation under general anesthesia. Necropsy revealed multiple pulmonary and hepatic soft-tissue nodules and an intracoelomic mass over the left kidney communicating with external subcutaneous masses and a pericloacal mass of similar gross appearance. Histopathologic findings identified a severe, disseminated, inflammatory infiltration of multiple tissues and multiple granulomas containing bizarre multinucleated cells. No causative agent of this granulomatous disease was identified. To our knowledge, this is the first report of systemic atypical granulomatous disease in Moluccan cockatoo. Traditional causes of granulomatous disease include mycotic disease, bacterial (ie, Mycobacterium) disease, and neoplasia. Attempts to identify an causative agent or neoplasia were unsuccessful. A retrospective review of pathology records revealed 2 additional cases with identical pathologic lesions. All 3 cases occurred in young Moluccan cockatoos and are assumed to be a disease of unknown origin that could be unique to this species.