Doxorubicin chemotherapy for presumptive cardiac hemangiosarcoma in dogs†

Sixty‐four dogs were treated with single‐agent doxorubicin (DOX) for presumptive cardiac hemangiosarcoma (cHSA). The objective response rate (CR + PR) was 41%, and the biologic response rate (CR + PR + SD), or clinical benefit, was 68%. The median progression‐free survival (PFS) for treated dogs was 66 days. The median survival time (MST) for this group was 116 days and was significantly improved compared to a MST of 12 days for untreated control dogs (P = 0.0001). Biologic response was significantly associated with improved PFS (P < 0.0001) and OS (P < 0.0001). Univariate analysis identified larger tumour size as a variable negatively associated with PFS. The high rate of clinical benefit and improved MST suggest that DOX has activity in canine cHSA.     

Effect of nanosilver(nAg) on disinfection,growth, and chemical composition of young barley leaves under in vitro conditions

Cereals, including barley, have been playing a key role in human diet for a long time. The objective of the present study was to determine the effect of nanosilver(nAg) on limitation of infections, morphological features, and their chemical composition of young barley seedlings under in vitro condition. Addition of 0, 2, 4, 6 and 8 mg dm~(–3) nAg into MS medium was used.Obtained results showed that the effect on the morphological features depended on the nAg concentration. The addition of 6 and 8 mg dm~(–3) nAg into MS medium limited the number of infected barley embryos in vitro, whereas 4 and 8 mg dm~(–3) nAg resulted in the highest seedlings with the longest roots. nAg in the medium affected the colour of leaves and increased the contents of chlorophyll and β-carotene, in particular in seedlings growing in MS medium supplied with 6 mg dm~(–3) nAg.The addition of 8 mg dm~(–3) had the greatest effect on the contents of vitamin C and E in young barley seedlings. It was found that the contents of K and Ca in the young barley leaves were lower, as compared to control plants. The presence of 6 mg dm~(–3) nAg in the medium resulted in an increased contents of N, Mg, Zn, Cu, and P. Hence, a diversified effect of nAg on individual groups of polyphenolic compounds was noticed. The presence of 2 and 8 mg dm~(–3) nAg caused higher content values of polyphenolic compounds in young barley leaves.     

An evaluation of two potential risk factors, MHC diversity and host density, for infection by an invasive nematode Ashworthius sidemi in endangered European bison (Bison bonasus)

Parasites are thought to increase the risk of host extinction, but their dynamics in endangered species have not been well investigated. The free-living European bison population in Bia?owie?a Forest has recently been massively invaded by a blood-sucking nematode, Ashworthius sidemi. This nematode originated in Asia and was probably transmitted to Europe with the introduction of the sika deer. Here, we investigate the impacts of genetic factors (the Major Histocompatibility Complex class II genes responsible for extracellular parasite recognition) and management practices (supplementary feeding affecting winter population density) on the intensity of A. sidemi infections in bison. All but two out of 110 animals investigated between 2005 and 2009 were infected with A. sidemi, and the intensity of infection increased significantly with time. Due to a severe population bottleneck experienced by the bison, only four class II DRB alleles are retained in the Bia?owie?a population. We found that despite high sequence divergence, neither any of the alleles nor DRB heterozygosity was significantly associated with infection intensity. We did find, however, that winter density of bison herds was positively associated with infection intensity. Winter bison population densities were in turn predicted by the intensity of supplementary feeding.     

A phase I clinical trial evaluating imatinib mesylate (Gleevec) in tumor-bearing cats

A phase I clinical trial evaluating the toxicity of orally-administered imatinib mesylate was performed in 9 tumor-bearing cats. Imatinib is a small molecule, tyrosine kinase inhibitor, which selectively blocks the function of overexpressed proteins associated with various malignancies. Cats included in the study had diagnoses of fibrosarcoma, squamous cell carcinoma, and mast cell tumor, and each cat was staged using CBC and serum biochemistry; urinalysis, thoracic radiographs, and abdominal ultrasonography were performed in some cats. Most cats were treated previously by surgery, radiation therapy, chemotherapy, or some combination of these treatments. None of the cats received any concurrent chemotherapy. Six cats were treated with imatinib mesylate at 1-2 mg/kg PO q24h. Dose escalations were made to 2, 4, and 10 mg/kg PO q24h in 5 cats. Two cats started therapy at 10 mg/kg PO q24h, and 1 cat started therapy at 15 mg/kg PO q24h; all 3 cats remained at these dosages. No signs of toxicity, as evaluated by CBC and serum biochemistry, were noted in 8 of the 9 cats, and minimal gastrointestinal toxicity was observed. Due to the low frequency of adverse effects, further evaluation of imatinib is ongoing at a dosage of 10 mg/kg PO q24h.     

Acquired amegakaryocytic thrombocytopenia--four cases and a literature review

Acquired amegakaryocytic thrombocytopenla was diagnosed in four dogs. Initial platelet counts in all four dogs were less than 50,000 x 10(9)/litre and initial bone marrow examinations revealed megakaryocytic hypoplasia with minimal changes in the erythroid and myeloid cell lines. Two dogs had evidence of idiopathic immune-mediated disease and two dogs had evidence of associated infectious disease. One dog had a positive antibody titre to Borrella burgdorferi, and one dog had positive titres to both Ehrlichia canis and B. burgdorferi. Treatment consisted of prednisone and cyclophosphamide for the dogs with presumptive immune-mediated disease, and prednisone and tetracycline for the dogs with positive antibody titres to the Infectious organisms. Both dogs with evidence of associated infectious disease responded to treatment. A postmortem examination did not reveal the underlying aetiology in the two dogs with presumptive idiopathic immune-mediated disease.     

Phase I clinical trial evaluating STI571 in tumor bearing cats

Introduction: STI571 (Gleevec, imatinib mesylate) is a receptor tyrosine kinase inhibitor with selectivity for Bcr‐Abl, platelet‐derived growth factor (PDGF), stem cell factor (SCF), and c‐Kit. Side effects with use in humans include vomiting, diarrhea, nausea, myalgia, edema, and cutaneous reactions. Renal and hepatic toxicity have also been reported. In dogs, there is significant hepatic toxicity at sub‐clinical doses. The purpose of this prospective study was to determine the toxicity level and potential treatment protocol in tumor bearing cats. Methods: A phase I clinical trial was performed in client owned cats using an escalating dose of STI571 in tumor bearing cats. Cats included in the study had a histologic diagnosis of fibrosarcoma or other tumors and were staged with CBC, biochemical profile, thoracic radiographs, and abdominal ultrasound. None of the cats received concurrent chemotherapy, but those previously treated with surgery, radiation therapy, or chemotherapy, were not excluded. The initial starting dose was 5 mg/cat PO SID and was gradually increased to 10 and 20 mg/cat PO SID at a 2–6 week interval depending on laboratory work and disease progression. A repeat physical examination, CBC, and biochemical profile, were performed every 2 weeks for 2 rechecks, then every 4 weeks. Results: Six cats were enrolled in the study. Four cats had oral squamous cell carcinoma, and two cats had cutaneous fibrosarcoma. One cat demonstrated leukocytosis, increased liver enzymes, and signs of acute renal failure two weeks after initiating therapy (5 mg PO SID). No dose escalation was made in this cat. Five cats endured dose escalations of 10 mg PO SID in two cats and 20 mg PO SID in three cats and were treated for 2–4 months. None of these cats experienced any signs of toxicity as measured by CBC and biochemical profile. Conclusions: Only one cat experienced toxicity that may have been associated with low dose administration of STI571. As most cats tolerated the drug without an adverse effect, further evaluation of STI571 in a phase II clinical trial is warranted.     

Pathological lesions in European bison (Bison bonasus) with infestation by Ashworthius sidemi (Nematoda, Trichostrongylidae)

Asworthius sidemi Schulz, 1933 is a blood sucking gastrointestinal nematode, primarily typical for Asiatic deer. It was found for the first time in Poland in European bison in 1997. To estimate the level of invasion of A. sidemi and histopathological changes connected with the presence of the parasite in the years 2004-2007 parasitological and histopathological examinations of 54 European bison from Bia?owieza Forest were carried out. Parasitological examination was carried out by the sedimentation method and A. sidemi were diagnosed under a binocular microscope. Samples for histological examination were collected from the abomasum and duodenum walls as well as from regional lymph nodes. Tissue samples were then fixed with 10% buffered formalin, embedded in paraffin, cut in to 5 microm thick sections and stained with hematoxylin and eosin (H&E). Parasitological examinations showed the presence of fourth stage larvae and juvenile forms of A. sidemi. The maximal intensity of invasion rose systematically from 4470 A. sidemi nematodes in 2004/2005 to 44310 in 2006/2007. Histopathological examinations showed infiltrations of inflammatory cells in the walls of abomasa and duodena at various levels of intensity (mainly lymphoid cells and eosinophils), hyperemiae, oedemae and lesions of mucosa and proliferation of lymphatic follicles. In individual cases of dysplasia of epithelial cells, atrophy or hyperplasia of glands and the presence of parasites in the lumen or walls of the abomasum/duodenum were observed. In one case, parasitic nodules were found. In regional lymph nodes proliferation of lymphatic follicles, presence of eosinophils and desolation of reproduction centers were observed. Intensification of histopathological changes was connected to a considerable degree with the developmental stage of A. sidemi as shown by parasitological examination.     

Asparaginase and MOPP Treatment of Dogs with Lymphoma

Background: Dogs with multicentric lymphoma are treated with various cyclophosphamide, doxorubicin, vincristine, and prednisone (CHOP)-based chemotherapy protocols with variable success.
Objectives: To describe the progression-free survival (PFS) time and overall survival time (OST) of dogs with T-cell lymphoma or hypercalcemic lymphoma treated with l -asparaginase and mechlorethamine, vincristine, prednisone, procarbazine (MOPP).
Animals: Fifty dogs with T-cell lymphoma, hypercalcemic lymphoma, or both treated at 3 referral veterinary hospitals.
Methods: Retrospective study. Case were selected based on histologic or cytologic diagnosis of lymphoma; presence of the T-cell phenotype, presence of hypercalcemia or both; and absence of previous chemotherapy. The T-cell phenotype was determined by flow cytometry, immunocytochemistry, immunohistochemistry, or polymerase chain reaction of antigen receptor rearrangement.
Results: The overall response rate was 98% (78% complete response, 20% partial response). The median PFS for the entire study population was 189 days with 25% PFS at 939 days. The median OST for the entire study population was 270 days with 25% surviving 939 days. Twenty percent of the dogs required hospitalization for treatment related complications.
Conclusions and clinical importance: l -Asp/MOPP chemotherapy might result in longer PFS and OST for dogs with multicentric T-cell lymphoma, dogs with hypercalcemic lymphoma or both, than achieved with CHOP.