Toxicology Case Presentations.

Owners are often not aware that some common household products, medications, and plants are toxic to dogs and cats. Six cases of toxicoses due to ingestion of xylitol, amatoxin-containing mushrooms, anticoagulant rodenticide, zinc, vitamin D, and lily are presented with typical clinical and laboratory data findings. Changes in the laboratory data are explained in the context of the mechanism of action of the toxin and the organ systems affected.

Pathology in Practice.

In collaboration with the American College of Veterinary Pathologists.

Pathology in Practice.

In collaboration with the American College of Veterinary Pathologists.

Comparison of pathologist review protocols for cytologic detection of prostatic and urothelial carcinomas in canines: A bi-institutional retrospective study of 298 cases.

Urothelial carcinoma, also known as transitional cell carcinoma, is the most common primary bladder tumour in dogs, and can also involve the prostate gland. Cytology is a common diagnostic tool utilized for dogs with bladder or prostate gland lesions. The objectives of this retrospective study were to compare the sensitivity and specificity of cytologic evaluation for urothelial or prostatic carcinoma between two institutions with different cytology review protocols as well as determine if certain collection methods resulted in higher cytologic accuracy. A total of 298 cases met inclusion criteria. The overall sensitivity and specificity for institution 1 were 91.8% and 50%, respectively, compared to 31.1% and 97.4%, respectively, for institution 2. When the urine sample review protocol at institution 2 was matched to that of institution 1, sensitivity and specificity were more similar to institution 1 (71.2% and 88.9%, respectively). Our results show that the sensitivity and specificity of cytology are affected by screening and review protocols implemented by different institutions. The data also demonstrate that sensitivity and specificity vary by collection method. Diagnostic catheterization had the highest performance: of the 11 cases between two institutions, it had 100% sensitivity and specificity. In contrast, examination of urine sediment not collected via diagnostic catheterization had low sensitivity and specificity that varied greatly by institution. In summary, cytologic interpretation should be undertaken with consideration given to both processing and collection protocols.

Lymphocytosis and lymphadenopathy in a dog arising from two distinct lymphoid neoplasms.

A 10-year-old intact male Golden Retriever was presented to The Ohio State University Veterinary Medical Center for acute, non-painful facial swelling of the right mandibular region. On physical examination, the right mandibular swelling was found to represent marked lymphadenopathy of the submandibular lymph node. At this time, marked lymphadenopathy of the prescapular and popliteal lymph nodes was also appreciated. The CBC showed a moderate leukocytosis (38.4 × 109 cells/L, reference interval [RI] 4.8-13.9 × 109 cells/L) characterized by a moderate lymphocytosis (28.4 × 109 cells/L, RI 1.0-4.6 × 109 cells/L). Evaluation of peripheral blood and enlarged prescapular and popliteal lymph nodes revealed two morphologically different populations of homogeneous lymphocytes, with the lymphocyte population in the lymph nodes being distinct from that in the blood smear. Flow cytometry of peripheral blood revealed CD45-, CD5+, CD4-, CD8-, variably CD21+ neoplastic lymphocytes compatible with T-zone lymphocytes due to the absence of CD45 expression. Flow cytometry of the lymph node aspirate indicated a distinct population of CD21+ lymphocytes consistent with a B-cell phenotype along with a smaller proportion of the T-zone lymphocytes observed in the blood confirming the presence of two distinct populations of neoplastic lymphocytes, one involving T cells, and the other involving B cells.

Fibrosarcoma with sarcomatosis and metastasis in a FeLV-negative cat.

A 6-year-old, spayed female, mixed shorthair cat presented to the emergency service at The Ohio State University Veterinary Medical Center for evaluation of hypercalcemia, a right eye mass, and multiple intrathoracic and intra-abdominal masses. Cytologic evaluation of one of the abdominal masses revealed a uniform population of large, anaplastic mesenchymal cells found individually, in loose aggregates, and occasionally associated with pink, extracellular matrix. The cytology was consistent with a malignant mesenchymal neoplasm, with primary consideration given to fibrosarcoma and hemangiosarcoma. The cat was euthanized and histopathology confirmed disseminated fibrosarcoma. Fibrosarcoma comprises 12%-41% of feline cutaneous tumors and affects cats at a mean age of 9.6 years. Three manifestations of fibrosarcoma predominate in cats: spontaneous solitary fibrosarcoma, vaccine-induced/injection site fibrosarcoma, and oncogene-induced (FSV) fibrosarcoma. The history, signalment, and results from diagnostics performed did not support solitary fibrosarcoma or injection-induced sarcoma. Although some criteria fit with virally induced fibrosarcoma, such as age and the presence of multiple fibrosarcomas, the neoplastic population was negative for FeLV IHC. The presence of fibrosarcomas throughout the pleural and peritoneal cavity was most compatible with sarcomatosis and the distant metastasis of an unidentified primary neoplasm. To the authors' knowledge, this is the first reported case of sarcomatosis in a FeLV-negative cat.

Persistent nonregenerative anemia in a 4-year-old cat.

A 4-year-old male neutered domestic shorthair cat was presented to The Ohio State University College of Veterinary Medicine for a 2-month history of severe weight loss, lethargy, anemia, and bilaterally hyperechoic kidneys with loss of corticomedullary distinction as reported by the referring veterinarian. Relevant initial laboratory results included severe non-regenerative normocytic hypochromic anemia, increased blood urea nitrogen, minimally concentrated urine, proteinuria, and an increased urine protein:creatinine ratio. Cytologic evaluation of a bone marrow aspirate revealed a markedly hypocellular marrow with abundant mucinous material. Gelatinous marrow transformation (GMT) was confirmed histologically by the presence of mucinous material in the bone marrow that stained positive for Alcian blue but negative for periodic acid-Schiff. The cat died despite repeated blood transfusions and supportive care. Gelatinous marrow transformation, immune complex-mediated membranoproliferative glomerulonephritis, and gastrointestinal hemorrhage were observed on autopsy and histology. It is likely that the development of GMT was secondary to chronic kidney disease (CKD) and that CKD, GMT, and gastrointestinal hemorrhage contributed to the cat's non-regenerative anemia.

Parasitemia due to Sarcocystis neurona-like infection in a clinically ill domestic cat.

An 8-year-old, 6-kg, male neutered Domestic Shorthair cat was presented to The Ohio State University Veterinary Medical Center (OSU-VMC) for difficulty breathing. Physical examination and thoracic radiographs indicated pneumonia, a soft-tissue mass in the left caudal lung lobe, and diffuse pleural effusion. The effusion was classified as modified transudate. Rare extracellular elongated (~5-7 µm × 1-2 µm) zoites with a central round to oval-shaped purple to deep purple vesicular nucleus with coarsely stippled chromatin and light blue cytoplasm were seen on a peripheral blood smear. Serum IgG and IgM were positive for Sarcocystis sp. antibodies and negative for Toxoplasma gondii antibodies, suggesting that the infection was acute rather than a recrudescence of prior infection. This organism was most consistent with either Sarcocystis neurona or Sarcocystis dasypi based on DNA sequence analysis of PCR products using COC ssRNA, ITS-1, snSAG2, and JNB25/JD396 primer sets. This is the first report to visualize by light microscopy circulating Sarcocystis sp. merozoites in the peripheral blood of a domestic cat. Therefore, Sarcocystis should be considered as a differential diagnosis in cats with suspected systemic protozoal infection.

Use of a combination of routine hematologic and biochemical test results in a logistic regression model as a diagnostic aid for the diagnosis of hypoadrenocorticism in dogs.

OBJECTIVE To assess the discriminatory value for corticosteroid-induced alkaline phosphatase (CiALP) activity and other variables that can be measured routinely on a CBC and biochemical analysis for the diagnosis of hypoadrenocorticism in dogs. SAMPLE Medical records of 57 dogs with confirmed hypoadrenocorticism and 57 control dogs in which hypoadrenocorticism was suspected but ruled out. PROCEDURES A retrospective case-control study was conducted. Dogs were included if a CBC and complete biochemical analysis had been performed. Dogs with iatrogenic hypoadrenocorticism and dogs treated previously with glucocorticoids were excluded. Cortisol concentration for dogs with hypoadrenocorticism was ≤ 2 µg/dL both before and after ACTH administration. Cortisol concentration for control dogs was > 4 µg/dL before or after ACTH administration. RESULTS Area under the receiver operating characteristic (ROC) curve for CiALP activity was low (0.646; 95% confidence interval, 0.494 to 0.798). Area under the ROC curve for a model that combined the CiALP activity, Na-to-K ratio, eosinophil count, activity of creatine kinase, and concentrations of SUN and albumin was high (0.994; 95% confidence interval, 0.982 to 1.000). Results for this model could be used to correctly classify all dogs, except for 1 dog with hypoadrenocorticism and no electrolyte abnormalities. CONCLUSIONS AND CLINICAL RELEVANCE CiALP activity alone cannot be used as a reliable diagnostic test for hypoadrenocorticism in dogs. Combined results for CiALP activity, Na-to-K ratio, eosinophil count, creatine kinase activity, and concentrations of SUN and albumin provided an excellent means to discriminate between hypoadrenocorticism and diseases that mimic hypoadrenocorticism.

Use of Lactate in Small Animal Clinical Practice.

Lactate is a product of anaerobic metabolism. Lactate concentration in blood is used clinically as an indicator of tissue hypoperfusion and hypoxia to determine disease severity, assess response to therapy, and predict outcome. This article reviews lactate physiology, sample collection and processing, and interpretation of lactate concentration in clinical practice.

Evaluation of the ability of a gravitational filtration system to enhance recovery of equine bone marrow elements.

OBJECTIVE: To assess efficiency of gravity filtration to enhance recovery of equine bone marrow elements including stem and progenitor cells. ANIMALS: 12 healthy adult horses. PROCEDURES: Bone marrow aspirates were collected from the fifth sternebral body and filtered by gravitational flow to obtain bone marrow elements. Raw and harvested bone marrow and marrow effluent were evaluated for WBC and platelet counts, automated and cytomorphologic cell differential counts, mesenchymal stem cell CFUs, cell viability, and differentiation capacity. Isolated cells were analyzed for CD90 and major histocompatibility complex (MHC) class I and II antigens. RESULTS: Mean cell viability of harvested bone marrow was 95.9%. Total WBCs and platelets were efficiently captured on the filter (> 95%), and mean recovery in harvested bone marrow was 30%. Cytologic cell differential counts indicated that the percentage of neutrophils was significantly less and the progenitor cell population was significantly higher and concentrated 1.56-fold in harvested bone marrow, compared with results for raw bone marrow. Flow cytometry and cell culture were used to characterize harvested bone marrow cells as positive for expression of CD90 and negative for MHCI and MHCII, which indicated stem cells with a multipotent phenotype that differentiated into chondrocytes, osteocytes, adipocytes, and tenocytes. CONCLUSIONS AND CLINICAL RELEVANCE: Gravitational filtration of bone marrow efficiently yielded platelets and cells and produced a progenitor-enriched, leukocyte-reduced product, compared with raw bone marrow.

Platelet vacuoles in a dog with severe nonregenerative anemia: evidence of platelet autophagy.

A 13-year-old neutered male English Springer Spaniel was presented to The Ohio State University Veterinary Medical Center for evaluation of severe anemia. Upon blood smear review, approximately 50% of the platelets contained single to multiple variably sized clear vacuoles. Transmission electron microscopy of the platelets revealed hallmark features of autophagy, including membrane-lined vesicles and vacuoles containing membrane whorls and degrading organelles. While autophagy has been demonstrated in a wide range of eukaryotic cells for decades, reports of platelet autophagy are lacking. This case report illustrates atypical platelet vacuolation with electron microscopic features characteristic of autophagy.

Evaluation of a single intra-articular injection of autologous protein solution for treatment of osteoarthritis in horses.

OBJECTIVE: To evaluate intra-articular autologous protein solution (APS) for the treatment of osteoarthritis in horses. Animals-40 client-owned horses with naturally occuring osteoarthritis. PROCEDURES: APS was generated from a dual-device system that concentrated plasma and WBC proteins and enriched platelet growth factors. Horses were randomly assigned to receive an intra-articular injection of 5 mL of saline (0.9% NaCl) solution (n = 20) or APS (20), exercised on a treadmill, and evaluated on the basis of lameness grades, kinetic gait analysis, joint circumference, and range of motion for 14 days. Horses that received saline solution were administered APS at termination of the study, and clients scored horses for lameness and discomfort before, 12 weeks after, and 52 weeks after the APS injection. RESULTS: The APS group had significant improvements in lameness grade, asymmetry indices of vertical peak force, and range of joint motion by 14 days, compared with baseline or control group values. No adverse effects associated with APS treatment were evident. Clients assessed lameness and comfort as improved at 12 and 52 weeks. The APS had greater likelihood (OR, 4.3 to 30.0) of a therapeutic response in horses with a lameness score < 4, < 10% vertical force asymmetry, or absence of marked osteophyte formation, subchondral sclerosis, or joint space narrowing. Concentration of interleukin-1 receptor antagonist in APS was 5.8 times that in blood. CONCLUSIONS AND CLINICAL RELEVANCE: Intra-articular administration of APS can be considered an effective treatment option for equine osteoarthritis, with the potential for disease-modifying effects.

Use of lactate in small animal clinical practice.

Lactate is a product of anaerobic metabolism. Lactate concentration in blood is used clinically as an indicator of tissue hypoperfusion and hypoxia to determine disease severity, assess response to therapy, and predict outcome. This article reviews lactate physiology, sample collection and processing, and interpretation of lactate concentration in clinical practice.

Investigation of the immune response to autologous, allogeneic, and xenogeneic mesenchymal stem cells after intra-articular injection in horses.

Mesenchymal stem cells have demonstrated immunomodulatory capabilities as well as modest efficacy in animal models of joint injury, warranting further study as a potential treatment of joint disease. The goal of the study was to investigate the blood and synovial immune and histologic response to intra-articular injection of autologous, allogeneic, and xenogeneic bone marrow-derived mesenchymal stem cells (MSC) in horses. The study group consisted of 6 five-year-old Thoroughbred mares that had been injected previously with 15 million, genetically modified autologous, allogeneic, or xenogeneic MSC into the fetlock joints. One group of autologous cells was genetically modified to permit MSC biolocalization in the synovium. To assess response to the injection, synovial biopsies were obtained via arthroscopy 60 days after MSC injection for gross, histologic and molecular analyses. Peripheral blood mononuclear cells were isolated from each horse 120 days after MSC injection and co-cultured with a monolayer of each MSC group to permit quantification of activated CD4+ lymphocytes and cytokine release (ELISA) upon re-exposure to MSC. Arthroscopic examination revealed normal synovium with no grossly detrimental effect to the synovium or cartilage. Intra-articular MSC produced a persistent mononuclear infiltrate for at least 60 days, mostly perivascular, identified as CD3+ lymphocytes. An immune response (significant increase in CD4+ lymphocytes) was detected upon re-exposure to xenogeneic but not to allogeneic or autologous MSC. An inflammatory cytokine release from peripheral blood mononuclear cell/MSC co-cultures was present in all MSC groups but was significantly greater in the xenogeneic group. In conclusion, intra-articular injection of MSC, regardless of cell origin, incited a persistent mononuclear synovitis demonstrating a sustained biologic influence of these cells. Allogeneic cells did not elicit a detectable immune response upon re-exposure using our methods.

Performance of a gravitational marrow separator, multidirectional bone marrow aspiration needle, and repeated bone marrow collections on the production of concentrated bone marrow and separation of mesenchymal stem cells in horses.

Objective-To determine the efficiency of a novel point-of-care gravitational marrow separator and bone marrow aspiration needle for concentrated bone marrow production and bone marrow-derived mesenchymal stem cell (MSC) separation and assess the effect of repeated bone marrow collections in horses. Animals-8 healthy adult horses. Procedures-Bone marrow aspiration was performed twice (1 month apart) from sternebral bodies with a standard or prototype multidirectional needle. Concentrated bone marrow was obtained by gravitational marrow separation and evaluated for WBC and platelet counts, automated and cytomorphologic cell differential counts, MSCs, and cell viability. Results-Concentrated bone marrow samples obtained with the marrow separator had 5- to 19-fold bone marrow-derived MSC, WBC, and platelet counts, compared with original bone marrow samples. Use of a multidirectional needle increased the frequency of obtaining MSC-richer concentrated bone marrow. Repeating bone marrow aspiration at 1 month yielded greater MSC numbers but slightly lower cell viability after processing. Conclusions and Clinical Relevance-The gravitational bone marrow separator and multidirectional needle were used to effectively harvest bone marrow and improve the quality of concentrated bone marrow. Comparable, or even greater, numbers of bone marrow-derived MSCs were collected by repeated bone marrow aspiration after a 1-month interval from the same aspiration sites. Use of the marrow separator and multidirectional bone marrow aspiration needle can facilitate a 1-step, point-of-care, nonlaboratory method to obtain concentrated bone marrow as a mixture of bone marrow-derived MSCs and growth factors from platelets and plasma.