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Introduction: The nitro blue tetrazolium (NBT) reduction test (NBTT) has been used for measuring the metabolic activity of phagocytes of mammals. Activated neutrophils transform NBT into formazan in the cytoplasm. The NBTT can detect the activation of neutrophils in peripheral blood and is used to assess neutrophil function in dogs. However, the NBTT is not used frequently in the clinical setting, as samples should be processed after blood collection., Objective: The aim of this study was to evaluate the effect of storage on NBTT in dog blood samples., Materials and Methods: Residual EDTA blood samples from 22 dogs were included of different ages, breeds, and sex. The buffy coat layer was separated from the blood and incubated with 0.1% NBT. The NBTT was performed at 0, 24, 48, and 72 h after the collection of blood. Blood samples were stored at 4°C until the tests were performed. Blood smears were evaluated by light microscopy, and the NBT reduction rate was reported, which represents the percentage of activated neutrophils. The NBT reduction rate was calculated after counting 300 neutrophils in each slide., Results: The means of NBTT in dog blood samples at 0, 24, 48, and 72 h were 8.3%, 8.5%, 8.7%, and 7.8%, respectively. No significant differences were observed between time points., Conclusions: This study showed that the NBTT can be performed up to 72 h after the collection of canine blood if correctly refrigerated at 4°C. This finding supports the performance of the NBTT in the clinical setting., (© 2023 The Authors. Veterinary Clinical Pathology published by Wiley Periodicals LLC on behalf of American Society for Veterinary Clinical Pathology.)

Cell cannibalism refers to the engulfment of cells by nonprofessional phagocytic cells. Studies in human medicine have demonstrated a relationship between the presence of cell cannibalism by neoplastic cells and a poor outcome, and have shown a positive correlation with the presence of metastasis at the time of diagnosis. The biologic significance of cell cannibalism is unknown, but it is proposed that it may represent a novel mechanism of tumor immune evasion as a survival strategy in cases of unfavorable microenvironmental conditions. This report describes clinical and morphologic features of 3 cases of dogs with malignant neoplasia in which the presence of cellular cannibalism was observed in cytologic and histologic specimens. In the 1(st) case, a dog with a primary tonsillar squamous cell carcinoma with metastasis to retropharyngeal lymph nodes had neoplastic epithelial cells engulfing neutrophils noted in cytologic examination of the lymph nodes. In the 2(nd) case, neoplastic epithelial cells were seen engulfing each other in fine-needle aspirates from a primary mammary carcinoma with lung metastasis. In the 3(rd) case, poorly differentiated neoplastic mast cells from a recurrent, metastatic grade III mast cell tumor were observed cannibalizing eosinophils. A brief review of the literature describing known cell-into-cell relationships and the possible biologic significance and mechanisms involved in this phenomenon is provided. The relationship between cell cannibalism and distant metastasis should be explored in further studies, as it may prove to be a criterion of malignancy, as it is proposed in human medicine., (© 2015 American Society for Veterinary Clinical Pathology.)

Background: Cytologic evaluation plays an important role in the diagnosis of ovarian neoplasia in dogs, but is supported by only scant information on cytologic features of canine ovaries., Objective: The aim of this study was to provide detailed cytologic descriptions of normal canine ovaries in different stages of estrus with comparison to histologic features., Methods: Client-owned dogs admitted for elective ovariohysterectomy were studied. For each dog, fine-needle aspirates of both ovaries were collected, stained, and examined and were compared with histologic sections of the same ovary. The stage of estrus was confirmed by examination of histologic sections and cytologic specimens of vaginal cells collected with swabs., Results: Thirty-two ovaries from 16 dogs were examined. Luteal cells were observed in 82% of the dogs in diestrus. In early diestrus these cells were polygonal with amphophilic to deeply basophilic cytoplasm, and in late diestrus luteal cells had blebbed cell borders and clear cytoplasm with numerous small vacuoles. Perivascular arrangements and leuko-emperipolesis were noted in both phases of diestrus. Granulosa cells and spindle cells were found in cytologic specimens from most of the ovaries, and blue-gray extracellular material, sometimes associated with granulosa cells, was present. Medium-sized discrete round cells of undetermined origin were observed in some stages of estrus, and structures classified as corpora albicans were noted occasionally., Conclusions: Knowledge of specific cytologic features of normal canine ovaries is important for identification of pathologic processes in this organ. The novel findings of luteal cell emperipolesis, extracellular material associated with granulosa cells, and round cells of undetermined lineage warrant further study, which may provide new information on canine ovarian structure and function., (© 2012 American Society for Veterinary Clinical Pathology.)

Background: Cerebrospinal fluid (CSF) is potentially altered by iatrogenic blood contamination at the time of sampling due to the addition of blood-associated leukocytes and protein., Objectives: The objective of this study was to assess whether protein concentration, neutrophil percentage, and the presence of activated macrophages, reactive lymphocytes, or eosinophils in CSF samples with low total nucleated cell concentration (TNCC) are affected by blood contamination or associated with central nervous system (CNS) disease., Methods: Case records from the Royal Veterinary College Diagnostic Laboratory were searched retrospectively for dogs with CSF having < or =5 TNCC/microL. TNCC, RBC, and protein concentrations; neutrophil percentage; and the presence of activated macrophages, reactive lymphocytes, and eosinophils were recorded. Results of magnetic resonance imaging (MRI) also were recorded as a marker of CNS disease., Results: Of 906 cases evaluated, 106 (12%) had blood contamination (>500 RBCs/microL) in CSF. Protein concentration and neutrophil percentage were significantly higher and the presence of eosinophils was more likely in blood contaminated vs noncontaminated samples. Non-blood-contaminated samples with activated macrophages or reactive lymphocytes had higher protein concentrations and neutrophil percentages, and those with activated macrophages were more likely to have a positive finding on MRI., Conclusions: Protein concentration, neutrophil percentage, and the presence of eosinophils are significantly affected by blood contamination in canine CSF having low TNCC. Activated macrophages and reactive lymphocytes are not affected by blood contamination, however, and may be useful in identifying dogs with CNS abnormalities.

Background: A review of the literature revealed limited information about the stability of samples for coagulation testing in dogs., Objective: The aim of this study was to evaluate the stability of individual coagulation factors, clotting times, and other parameters of hemostasis in stored canine plasma., Methods: Citrated plasma samples were obtained from 21 dogs. Prothrombin time (PT), activated partial thromboplastin time (aPTT), fibrinogen concentration, and factor I, II, V, VII, VIII, IX, X, XI, and XII activities were measured on an automated coagulation analyzer with commercially available reagents. Antithrombin (AT) activity and D-dimer concentration were measured on an automated chemistry analyzer using validated kits. Samples were analyzed within 1 hour after collection (initial analysis) and once daily for 2 or 4 consecutive days following storage at room temperature (RT) or 4 degrees C, respectively., Results: Storage time at either temperature did not have any effect on PT, factor II, V, VII, X, or XII activities, D-dimer concentration, or AT activity. In contrast, aPTT was significantly prolonged after 72 and 96 hours at 4 degrees C; fibrinogen concentration was decreased after 48 hours at RT; the activities of factors VIII and IX were decreased after 48, 72, and 96 hours at 4 degrees C; and factor XI activity was decreased after 72 hours at 4 degrees C., Conclusions: Results suggest that storage of canine plasma for 2 days at RT does not have a significant effect on hemostasis test results with the exception of a slight decrease in fibrinogen concentration. In contrast, aPTT and factors VIII, IX, and XI were unstable in refrigerated plasma after 48 or 72 hours of storage.

Background: Artifactual changes in blood may occur as a consequence of delayed analysis and may complicate interpretation of CBC data., Objective: The aim of this study was to characterize artifactual changes in canine blood, due to storage, using the ADVIA 120 hematology analyzer., Methods: Blood samples were collected into EDTA from 5 clinically healthy dogs. Within 1 hour after blood sample collection and at 12, 24, 36 and 48 hours after storage of the samples at either 4 degrees C or room temperature (approximately 24 degrees C), a CBC was done using the ADVIA 120 and multispecies software. A linear mixed model was used to statistically evaluate significant differences in values over time, compared with initial values., Results: The HCT and MCV were increased significantly after 12 hours of collection at both 4 degrees C and 24 degrees C, and continued to increase through 48 hours. The MCHC initially decreased significantly at 12-24 hours and then continued to decrease through 48 hours at both temperatures. Changes in HCT, MCV, and MCHC were greater at 24 degrees C than at 4 degrees C at all time points. A significant increase in MPV and a decrease in mean platelet component concentration were observed at all time points at 24 degrees C. Samples stored at 24 degrees C for 48 hours had significantly higher percentages of normocytic-hypochromic RBCs, and macrocytic-normochromic RBCs, and lower platelet and total WBC counts., Conclusions: Delayed analysis of canine blood samples produces artifactual changes in CBC results, mainly in RBC morphology and platelet parameters, that are readily detected using the ADVIA 120. Refrigeration of specimens, even after 24 hours of storage at room temperature, is recommended to improve the accuracy of CBC results for canine blood samples.

Background: Eccentrocytes are RBCs that appear in a peripheral blood smear to have their hemoglobin shifted to one side of the cell. This abnormality, which is confined to the RBC membrane and cytoskeleton, is induced by oxidative damage. Eccentrocytes have been reported rarely in dogs and are associated with onion and garlic ingestion and the administration of oxidant drugs., Objective: The purpose of this study was to describe the occurrence and severity of eccentrocytosis in dogs and the diseases or disorders associated with eccentrocytes., Methods: Detailed history, and results of physical examination, CBC, biochemical and coagulation profiles, and urinalysis from all canine patients admitted during a 2.5-year period were evaluated. Eccentrocytes, when observed, were graded 1+ (few) to 4+ (many). The severity of eccentrocytosis was compared with that of anemia and reticulocytosis., Results: Eccentrocytes were found in blood smears from 60 of 4251 dogs (1.4%) and were associated with mild to moderate anemia in 40 (66.6%) of the cases. Eccentrocytosis was found in 16 (26.6%) dogs with drug administration, 11 (18.3%) with presumptive onion and garlic ingestion, 8 (13.3%) with vitamin K antagonist intoxication, 7 (11.6%) with ketoacidotic diabetes, 5 (8.3%) with T-cell lymphoma, 4 (6.6%) with severe infections, 1 (1.6%) with compensated diabetes mellitus, and 8 (13.3%) with other conditions. Certain dog breeds, such as Whippet, Boxer, and English Setter, and young dogs seemed to be overrepresented., Conclusions: We describe, for the first time, associations between eccentrocytes and diabetes mellitus, T-cell lymphoma and vitamin K antagonist intoxication in dogs. The significance of eccentrocytes should not be underestimated, because they can be a signal of an oxidative process.