Browsing by Author "Lenz, S. D."

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    Characterization of temperature-sensitive strains of Neospora caninum in mice
    Lindsay, David S.; Lenz, S. D.; Blagburn, B. L.; Brake, D. A. (American Society of Parasitology, 1999-02)
    Temperature-sensitive (ts) strains of the Neospora caninum tachyzoites were selected by chemical mutagenesis and selection for growth at 32 C. Three ts strains and the parental, N. caninum wild-type strain, NC-1, were examined in the present study for their ability to cause disease in inbred BALB/c mice, outbred ICR mice, and chemically immunosuppressed ICR mice. In BALB/c mice, all 3 strains failed to induce clinical disease, whereas infection with the NC-1 strain caused central nervous system disease and death in some mice. No disease was observed in ICR mice inoculated with the 3 ts strains or the NC-I strain. All immunosuppressed ICR mice inoculated with the NC-1 strain died, whereas no immunosuppressed mice inoculated with the NCts-4 strain and only 1 of 5 mice inoculated with the NCts-8 and NCts-12 strains died. The NCts-4 and NCts-12 strains reverted to a wild-type phenotype when grown at 37 C. Vaccination of BALB/c mice with live, but not frozen NCts-8 strain tachyzoites induced significant (P < 0.05) protection following NC-1 strain challenge.
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    Recommended Guidelines for the Conduct and Evaluation of Prognostic Studies in Veterinary Oncology
    Webster, J. D.; Dennis, M. M.; Dervisis, Nikolaos G.; Heller, J.; Bacon, N. J.; Bergman, P. J.; Bienzle, D.; Cassali, G.; Castagnaro, M.; Cullen, J.; Esplin, D. G.; Pena, L.; Goldschmidt, M. H.; Hahn, K. A.; Henry, C. J.; Hellmen, E.; Kamstock, D.; Kirpensteijn, J.; Kitchell, B. E.; Amorim, R. L.; Lenz, S. D.; Lipscomb, T. P.; McEntee, M.; McGill, L. D.; McKnight, C. A.; McManus, P. M.; Moore, A. S.; Moore, P. F.; Moroff, S. D.; Nakayama, H.; Northrup, N. C.; Sarli, G.; Scase, T.; Sorenmo, K.; Schulman, F. Y.; Shoieb, A. M.; Smedley, R. C.; Spangler, W. L.; Teske, E.; Thamm, D. H.; Valli, V. E.; Vernau, W.; von Euler, H.; Withrow, S. J.; Weisbrode, S. E.; Yager, J.; Kiupel, M. (SAGE, 2011-01-01)
    There is an increasing need for more accurate prognostic and predictive markers in veterinary oncology because of an increasing number of treatment options, the increased financial costs associated with treatment, and the emotional stress experienced by owners in association with the disease and its treatment. Numerous studies have evaluated potential prognostic and predictive markers for veterinary neoplastic diseases, but there are no established guidelines or standards for the conduct and reporting of prognostic studies in veterinary medicine. This lack of standardization has made the evaluation and comparison of studies difficult. Most important, translating these results to clinical applications is problematic. To address this issue, the American College of Veterinary Pathologists’ Oncology Committee organized an initiative to establish guidelines for the conduct and reporting of prognostic studies in veterinary oncology. The goal of this initiative is to increase the quality and standardization of veterinary prognostic studies to facilitate independent evaluation, validation, comparison, and implementation of study results. This article represents a consensus statement on the conduct and reporting of prognostic studies in veterinary oncology from veterinary pathologists and oncologists from around the world. These guidelines should be considered a recommendation based on the current state of knowledge in the field, and they will need to be continually reevaluated and revised as the field of veterinary oncology continues to progress. As mentioned, these guidelines were developed through an initiative of the American College of Veterinary Pathologists’ Oncology Committee, and they have been reviewed and endorsed by the World Small Animal Veterinary Association.
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    Vaccination of mice with Neospora caninum: Response to oral challenge with Toxoplasma gondii oocysts
    Lindsay, David S.; Lenz, S. D.; Dykstra, C. C.; Blagburn, B. L.; Dubey, Jitender P. (American Society of Parasitology, 1998-04)
    Neospora caninum is a protozoan parasite that can cause severe disease in mammals. Two experiments were conducted to examine the effects of subcutaneous (s.c.) vaccination with Hank's balanced salt solution (HBSS), 1 x 10(5) N. caninum NC-1 strain tachyzoites or 1 x 10(5) Toxoplasma gondii TS-4 strain tachyzoites on challenge oral infections in mice with sporulated VEG strain T. gondii oocysts (1 x 10(3) oocysts exp. 1 and 5 x 10(3) oocysts exp. 2). An additional study, experiment 3, evaluated s.c. challenge with 2.5 x 10(3) tachyzoites of the highly virulent RH strain of T. gondii after vaccination with HBSS, NC-1 tachyzoites, or TS-4 tachyzoites. Mice vaccinated with NC-1 strain tachyzoites survived significantly (P < 0.05) longer than mice given HBSS in experiment 1, but not in experiments 2 and 3. Mice vaccinated with TS-4 strain tachyzoites survived significantly longer than HBSS-vaccinated mice in experiments 1, 2, and 3 and significantly longer than mice vaccinated with the NC-1 strain in experiments 2 and 3. Toxoplasma gondii tissue cyst numbers were significantly lower for mice vaccinated with TS-4 strain tachyzoites than mice vaccinated with HBSS or the NC-1 strain tachyzoites in experiment 1. No difference was observed in tissue cyst numbers in mice vaccinated with HBSS or NC-1 strain tachyzoites in experiment 1. No HBSS-vaccinated mice survived experiment 2, and the numbers of T. gondii tissue cysts were significantly lower for mice vaccinated with the TS-4 strain tachyzoites compared to NC-1 strain tachyzoites. No HBSS- or NC-1-vaccinated mice survived RH strain challenge in experiment 3. Results of these experiments indicate that infection with N. caninum provides some protection against fatal oral infection with T. gondii oocysts of a moderately pathogenic strain but not tachyzoites of a highly pathogenic strain. The protection provided bq N. caninum is much less than that provided by previous exposure to T. gondii, and the numbers of tissue cysts in the brains of mice are not significantly (P > 00.5) lowered.