Abstract
Serum from 440 Department of Defense working dogs was tested for antibodies against Borrelia burgdorferi using a commercially available ELISA kit (LymeCHEK, Synbiotics Corp., San Diego, CA) and by western blot analysis. When compared to the results obtained with western blotting, ELISA testing yielded no false positive results; however, false negative results were obtained in some cases. Overall, the specificity of the ELISA assay was 100%, the sensitivity was 82%, the positive predictive value was 100%, and the negative predictive value was 94%. Testing by ELISA could not distinguish between active infection and vaccination response. This information is essential for determining a treatment regimen. Furthermore, with the ELISA assay, there is a potential for cross-reactivity with antigens of other infectious agents. Drawbacks to the use of western blotting for diagnosis include lack of standardization and the increased expense and time required.
Sheets JT, Rossi CA, Kearny BJ, Moore GE: Evaluation of a commercial enzyme-linked immunosorbent assay for detection of Borrelia burgdorferi exposure in dogs. J Am Vet Med Assoc
First reported in 1969, hemorrhagic nephritis enteritis of geese (HNEG) causes high morbidity and mortality in geese 4–10 weeks of age. The disease occurs in Europe as an epizootic. In infected animals, nervous signs, coma, and death are observed clinically. Necropsy usually reveals subcutaneous edema, ascites, nephritis, and hemorrhagic enteritis. A group of French scientists recently isolated a novel polyomavirus from the tissues of affected geese. Nucleotide sequence analysis revealed that the virus is only distantly related to other avian polyomaviruses and is highly divergent from the virus causing budgerigar fledgling disease. Inoculation of tissue extracts containing this novel polyomavirus into goslings reproduced HNEG.
Guerin JL, Gelfi J, Dubois L, Vuillaume A, Boucraut- Baralon C, Pingret JL: A novel polyomavirus (goose hemorrhagic polyomavirus) is the agent of hemorrhagic nephritis enteritis of geese. J Virol
Chronic copper toxicity caused death in 15% of cattle fed poultry litter in a Brazilian feedlot. Cattle were fed 5–12 kg/animal/day of poultry litter, Cameron grass forage, small amounts of corn, and a commercial mineral supplement. The poultry diet contained 350 g of copper sulfate per 2000 kg of ration to prevent aspergillosis. Clinical signs in affected cattle included depression, anorexia, icterus, hemoglobinuria, and constipation or diarrhea. At necropsy, icterus, a yellowish liver, and dark kidneys were seen. There were microscopic lesions of centrolobular hepatic necrosis and renal tubular necrosis. Copper levels were 2000–5000 ppm in the livers of affected cattle, 350 ppm in poultry litter, 5 ppm in Cameron grass, and 2000 ppm in the commercial mineral supplement available to the cattle. Although feeding dried poultry litter is an inexpensive way to provide dietary nitrogen and phosphorus to cattle and to dispose of poultry waste, unexpected complications may arise.
Tokarnia CH, Döbereiner J, Peixoto PV, Moraes SS: Outbreak of copper poisoning in cattle fed poultry litter. Vet Human Toxicol
A recently reported study compared the results of fixing frozen sections in acetone and in pararosaniline for immunohistochemistry to detect unstable determinants (intracellular cytokines, co-stimulatory molecules, and specific antibody in plasma cells). Human, non-human primate, and mouse tissues were examined. The investigators reached the following conclusions: 1) In most tissues, pararosaniline fixation produced better morphology than acetone fixation, since individual cells could be distinguished more readily and determination of cell type was easier. 2) Pararosaniline completely blocked endogenous peroxidase and alkaline phosphatase activity in all tissues examined, but acetone was not successful in all tissues. 3) For some antibodies, pararosaniline fixation increased staining intensity. 4) Hematoxylin counterstaining was stronger with pararosaniline than with acetone. 5) Although antigen preservation does not differ between acetone and pararosaniline for most markers, there were a few markers for which pararosaniline fixation resulted in detection of fewer antigen-positive cells.
Schrijver IA, Melief MJ, van Meurs M, Companjen AR, Laman JD: Pararosaniline fixation for detection of co-stimulatory molecules, cytokines, and specific antibody. J Histochem Cytochem
The concept of multistage cancer development in humans is well-accepted, and excellent animal models for studying the evolution of carcinomas are available. However, it has been more difficult to apply the multistage concept to sarcomas. The authors of a recently published article have suggested that biomaterial-induced sarcomas in rats might provide insight into the stepwise development of sarcomas. A high proportion of rats with subcutaneously implanted biomaterials (polymers, metals, and ceramics) developed sarcomas at the implantation site. The sarcomas that arose included malignant fibrous histiocytomas, pleomorphic sarcomas, fibrosarcomas, leiomyosarcomas, malignant hemagiopericytomas, hemangiosarcoma, and sarcomas with mixed differentiation. Putative pre-neoplastic lesions were also identified. These lesions consisted of proliferative foci with varying degrees of atypia. The nuclei of cells comprising these foci stained intensely for proliferating cell nuclear antigen; thus, the foci were readily detectable. Based on their studies, the authors concluded that this was a promising model for studying the stages of sarcoma development.
Kirkpatrick CJ, Alves A, Köhler H, Kriegsmann J, Bittinger F, Otto M, Williams DF, Eloy R: Biomaterial-induced sarcoma: a novel model to study preneoplastic change. Am J Pathol
There are a number of reports indicating that the T cells of tumor-bearing mice are functionally defective. In a recent report, investigators characterized T cell function in mice of several strains bearing transplanted tumors, using both in vivo and in vitro assays. Surprisingly, these mice were able to prime T cell immune responses to keyhole limpet hemocyanin in vivo and to reject both allogeneic and syngeneic regressor tumors. Furthermore, CD8+ cytotoxic lymphocytes developed in the splenocytes of these mice following in vitro priming. As previously reported, spleen cells from tumor-bearing mice showed reduced proliferation in response to T cell activation in vitro. However, CD3+ T cells purified from the spleens of these animals proliferated normally in response to T cell receptor ligation in vitro. The authors postulated that the increased numbers of macrophages and neutrophils found in the spleens of tumor-bearing mice compared to control mice interfered with T cell responses in in vitro assays using total splenocytes. This interference may be due to a decrease in the relative abundance of T cells due to dilution by other cell types or to the production of immunosuppressive cytokines by these macrophages and neutrophils.
Radoja S, Rao TD, Hillman D, Frey AB: Mice bearing latestage tumors have normal functional systemic T cell responses in vitro and in vivo. J Immunol