Avian Health across the Landscape: Nestling Immunity Covaries with Changing Landcover.

The landscape composition of an organism's home range or territory should influence aspects of its condition, including measures of immune function. Changes in immunocompetence arising from variation in landcover may provide important links between habitat changes and patterns of disease spread. To establish a baseline understanding for whether immune measures covary with changes in landcover, we examined associations between immunological parameters and landcover composition for adults and nestlings of five shrubland bird species. Specifically, we examined the bacteria-killing ability (BKA) of the blood plasma and profiles of the five avian leukocytes as our measures of immune function, and assessed the proportion of area around each bird's nest that was composed of the four major landcover types in the Midwestern USA: row crop agriculture, developed, forest, and grass/shrub. We performed landcover assessments at 100 and 1000 m radius buffers to identify whether associations between habitat and immune function differed at the two spatial scales. As part of this work, we examined age and species-related immunological variation, as well as associations among the immune parameters. There was little evidence linking variation in immune function to landcover composition for the adults at either spatial scale, but there were numerous associations for nestlings, and these were stronger at the 1000 than 100 m spatial scale. The proportion of grass/shrub around the nest had the largest impact on immune function, although the effect varied by immune parameter and species. BKA and basophils were inversely associated with grass/shrub for all species, whereas lymphocytes were positively associated with grass/shrub for all species. We also documented species-level differences among adults and nestlings for BKA and all leukocytes except monocytes. As expected, we found that nestlings had reduced levels of BKA, lymphocytes, monocytes, and elevated heterophils compared with adults (except for field sparrow-Spizella pusilla-nestlings, which had higher lymphocytes). Basophils generally did not differ by age class, and eosinophils exhibited species-specific patterns, in which they were higher for nestling American robins (Turdus migratorius) and gray catbirds (Dumetella carolinensis) compared with adults, but lower in the other nestlings. Heterophils and lymphocytes were inversely associated for all species and age classes, and basophil levels were positively associated with BKA across species and age classes. Together, these findings bolster our understanding of age and species-specific variation in immune function, and provide evidence that immune measures can covary with changes in landcover.

Diagnosis and ultrasonographic appearance of hepatic metastasis in six cases of canine appendicular osteosarcoma (2005-2013).

OBJECTIVES: The aims of this retrospective study were to identify clinical cases of dogs with appendicular osteosarcoma (OSA) in which hepatic metastasis was confirmed, to highlight the use of cytology for its diagnosis and to describe the radiographic and ultrasonographic appearances of the lesion. METHODS: Medical records were retrospectively reviewed for dogs with appendicular OSA and hepatic metastases between January 2005 and January 2013. Reviews of radiographs, ultrasounds and cytology were performed. RESULTS: Six dogs with appendicular OSA and hepatic metastases were identified. The ultrasonographic appearance of metastatic lesions varied, including hyperechoic with shadowing, hyperechoic without shadowing, hypoechoic and mixed echogenicity. In two cases, the hepatic metastases were also evident on thoracic radiographs. The mean survival time from diagnosis of appendicular OSA was 188 days (range 69-363 days) and from diagnosis of hepatic metastases was 35 days (range 2-69 days). Death was tumour-related in all cases. CONCLUSIONS: Hepatic metastasis varies widely in its ultrasonographic appearance. In three of six cases, hepatic metastasis was identified without concurrent pulmonary metastasis; therefore, abdominal ultrasound may be useful at regular intervals for patient evaluation, especially in clinical trials where accurate identification of the disease-free interval is crucial. Once hepatic metastasis is confirmed, survival times appear limited.

Cathepsin K expression and activity in canine osteosarcoma.

BACKGROUND: Cathepsin K (CatK) is a lysosomal protease with collagenolytic activity, and its secretion by osteoclasts is responsible for degrading organic bone matrix. People with pathologic bone resorption have higher circulating CatK concentrations. HYPOTHESIS: Canine osteosarcoma (OS) cells will possess CatK, and its secretion will be cytokine inducible. Circulating CatK concentrations will be increased in dogs with OS, and will be a surrogate marker of bone resorption. ANIMALS: Fifty-one dogs with appendicular OS and 18 age- and weight-matched healthy control dogs. METHODS: In a prospective study, expressions of CatK mRNA and protein were investigated in OS cells. The inducible secretion and proteolytic activity of CatK from OS cells was assessed in vitro. Serum CatK concentrations were quantified in normal dogs and dogs with OS and its utility as a bone resorption marker was evaluated in dogs with OS treated with palliative radiation and antiresorptive agents. RESULTS: Canine OS cells contain preformed CatK within cytoplasmic vesicles. In OS cells, TGFß1 induced the secretion of CatK, which degraded bone-derived type I collagen in vitro. CatK concentrations were higher in dogs with OS than healthy dogs (11.3 ± 5.2 pmol/L versus 8.1 ± 5.0 pmol/L, P = .03). In a subset of dogs with OS, pretreatment CatK concentrations gradually decreased after palliative radiation and antiresorptive treatment, from 9.3 ± 3.2 pmol/L to 5.0 ± 3.1 pmol/L, P = .03. CONCLUSIONS AND CLINICAL IMPORTANCE: Canine OS is associated with pathologic bone resorption, and CatK inhibitors might aid in the management of canine OS-related malignant osteolysis.

Investigating TrkA expression in canine appendicular osteosarcoma.

BACKGROUND: The tropomyosin-related kinase A (TrkA) proto-oncogene encodes for a receptor that binds with high affinity to the neurotrophin ligand, nerve growth factor (NGF). Intracellular signaling mediated by the TrkA/NGF axis orchestrates neuronal cell differentiation, mitogenesis, and survival. Interestingly, TrkA also is expressed by bone forming cells, and its signaling promotes antiapoptotic effects in actively dividing osteoblasts. HYPOTHESIS: In canine immortalized cell lines and naturally occurring tumor samples, osteosarcoma (OSA) cells will express TrkA. In canine OSA cell lines, TrkA signaling will promote cell mitogenesis and survival. METHODS: In vitro, TrkA expression in canine OSA cell lines was assessed by reverse transcriptase-polymerase chain reaction, flow cytometry, and immunocytochemistry. In vitro, the involvement of TrkA-mediated signaling for cell mitogenesis and survival were investigated with commercially available assays. In vivo, TrkA expression was evaluated in primary tumors and pulmonary metastases with immunocytochemistry and immunohistochemistry, respectively. RESULTS: In vitro, canine OSA cells expressed TrkA mRNA and protein. Ligation of TrkA with exogenous NGF did not induce mitogenesis. Blockade of TrkA signaling with either a protein kinase inhibitor or NGF-neutralizing antibody induced apoptosis of canine OSA cell lines. In vivo, the majority (10/15) of canine OSA primary tumors and pulmonary metastases (9/12) expressed TrkA protein. CONCLUSIONS AND CLINICAL IMPORTANCE: Canine OSA cells express TrkA, and its signaling protects against apoptosis. Most dogs with spontaneously arising OSA express TrkA within their primary tumors and pulmonary metastatic lesions, warranting further investigations with TrkA antagonists as a novel treatment option for canine OSA.

Investigating CXCR4 expression in canine appendicular osteosarcoma.

BACKGROUND: Chemokine receptors (CXCRs) are transmembrane proteins classically studied for their participation in leukocyte homing. By their binding of cognate ligands, CXCRs orchestrate key cellular processes, including directional migration. Several different CXCRs are expressed on cancer cells and dictate tissue-specific metastases. In pediatric osteosarcoma (OSA), CXCR4 expression by tumor cells may participate in metastasis to tissues containing CXCL12, the partnering ligand for CXCR4. Canine and pediatric OSA share many biological similarities, including preferential metastasis to lung, bone, and lymph node. HYPOTHESIS: In canine immortalized cell lines and naturally occurring tumor samples, OSA cells will express CXCR4. In canine OSA cell lines, CXCR4 will participate in directional cell migration. METHODS: In vitro, CXCR4 expression in canine OSA cell lines was assessed by reverse-transcriptase polymerase chain reaction, Western blot analysis, flow cytometry, and immunocytochemistry. In vitro, involvement of CXCR4-mediated signaling for directional migration was investigated with a commercial assay. In vivo, CXCR4 expressions were evaluated in primary tumors and pulmonary metastases with immunocytochemistry and immunohistochemistry, respectively. RESULTS: In vitro, canine OSA cells express CXCR4 mRNA and protein. Ligation of CXCR4 with exogenous CXCL12 results in directional migration of canine OSA cell lines. In vivo, majority (8/11) of the canine OSA primary tumors, but minority (2/8) of the pulmonary metastases express CXCR4 protein. CONCLUSIONS AND CLINICAL IMPORTANCE: Canine OSA cells express CXCR4, and its signaling participates in directional migration. Most dogs with spontaneously arising OSA express CXCR4 within their primary tumors.

In vivo and in vitro efficacy of zoledronate for treating oral squamous cell carcinoma in cats.

BACKGROUND: Feline oral squamous cell carcinoma (OSCC) may cause painful bone destruction. Given the local invasiveness and rapid clinical progression of OSCC, conventional therapies are often palliative. In human cancer patients, zoledronate exerts anticancer effects by inhibiting tumor-induced angiogenesis and malignant osteolysis. HYPOTHESIS: Zoledronate will exert in vitro and in vivo anti-angiogenic and antiresorptive effects in feline OSCC. ANIMALS: Eight cats with OSCC were prospectively treated with zoledronate and conventional treatment modalities. METHODS: In vitro, zoledronate's effects in modulating soluble vascular endothelial growth factor (VEGF) secretion and receptor activator of nuclear factor kappaB (NF-kappaB) ligand (RANKL) expression were investigated in a feline OSCC cell line (SCCF1). In vivo, basal serum C-telopeptide (CTx) concentrations were compared among normal and OSCC-bearing cats, and the biologic effects of zoledronate administration in cats with naturally occurring OSCC were quantified by serially assessing circulating serum VEGF and CTx concentrations. RESULTS: In vitro, zoledronate concentrations greater than 3 microM reduce soluble VEGF secretion in the SCCF1 cell line. The expression of RANKL in the SCCF1 cell line was also modulated by zoledronate, with low concentrations (3 microM) decreasing but higher concentrations (30 microM) increasing RANKL expression in comparison with untreated cells. In vivo, cats with bone-invasive OSCC had greater serum CTx concentrations in comparison with geriatric, healthy controls. Treatment with zoledronate rapidly decreased circulating serum VEGF and CTx concentrations in cats with spontaneously occurring OSCC. CONCLUSIONS AND CLINICAL IMPORTANCE: Zoledronate exerts in vitro and in vivo effects that may favor the slowing of tumor growth and pathologic bone turnover associated with OSCC.

Clinicopathological findings and results of bone marrow aspiration in dogs with cutaneous mast cell tumours: 157 cases (1999-2002).

Bone marrow aspiration for routine staging of canine cutaneous mast cell tumour is not consistently performed, and the overall incidence of bone marrow infiltration and predictive value of the complete blood count (CBC) is unknown. This study evaluated a series of 157 dogs presented for cutaneous mast cell tumours in which a CBC and bone marrow aspiration were performed. The incidence of bone marrow infiltration at initial staging was low at 2.8%, and 4.5% overall. Factors significantly associated with bone marrow infiltration included increased age, leucocytosis, anaemia, neutrophilia, monocytosis, eosinophilia, thrombocytopenia, being purebred and staging at the time of recurrent or progressive disease. Our study suggests that a bone marrow sample is not indicated for routine staging but maybe indicated for those dogs with mast cell tumours having either an abnormal haemogram (neutrophilia, monocytosis, eosinophilia, basophilia, anaemia and thrombocytopenia) or presenting for tumour regrowth, progression or new occurrence.

Assessment of corticosteroid-induced alkaline phosphatase as a prognostic indicator in canine lymphoma.

OBJECTIVES: To examine the incidence of elevated corticosteroid-induced alkaline phosphatase (sALP) in dogs with lymphoma and to determine if sALP is a reliable prognostic indicator in canine lymphoma. METHODS: The medical records of 62 canine lymphoma patients treated with a combination chemotherapy protocol from 1994 to 2003 at the University of Illinois Veterinary Teaching Hospital were examined. Variables assessed with respect to response rate and remission duration included age, bodyweight, sex, breed, World Health Organization stage (I to V), substage (a or b), pretreatment administration of corticosteroid, and serum levels of alkaline phosphatase, sALP and alanine aminotransferase. RESULTS: sALP was not statistically significant with respect to response rate or duration of remission, nor was preinduction glucocorticoid administration. Stage was significant with respect to achieving remission. CLINICAL SIGNIFICANCE: It was found that sALP is not a useful prognostic indicator for response rate and remission duration in dogs with lymphoma.