Search

BACKGROUND: Intravesical administration of interleukin 12 (IL-12) co-formulated with the biopolymer, chitosan (CS/IL-12), has demonstrated remarkable antitumor activity against preclinical models of bladder cancer. However, given historical concerns regarding severe toxicities associated with systemic IL-12 administration in clinical trials, it is important to evaluate the safety of intravesical CS/IL-12 prior to clinical translation. OBJECTIVE: To evaluate the pharmacokinetics as well as the local and systemic toxicities of intravesical CS/IL-12 immunotherapy in laboratory mice. METHODS: Local inflammatory responses in mouse bladders treated with intravesical IL-12 or CS/IL-12 were assessed via histopathology. Serum cytokine levels following intravesical and subcutaneous (s.c.) administrations of IL-12 or CS/IL-12 in laboratory mice were compared. Systemic toxicities were evaluated via body weight and liver enzyme levels. RESULTS: Intravesical IL-12 and CS/IL-12 treatments did not induce significant local or systemic toxicity. IL-12 dissemination and exposure from intravesical administration was significantly lower compared to s.c. injections. Weekly intravesical CS/IL-12 treatments were well-tolerated and did not result in blunted immune responses. CONCLUSIONS: Intravesical CS/IL-12 is safe and well-tolerated in mice. In particular, the lack of cystitis and acute inflammation justifies continued investigation of intravesical CS/IL-12 immunotherapy in larger animals and patients with bladder cancer.

Conventional veterinary training emphasizes correct methodologies, potentially failing to exploit learning opportunities that arise as a result of errors. Error management training (EMT) encourages mistakes during low-stakes training, with the intention of modifying perceptions toward errors and using them to improve performance in unfamiliar scenarios (adaptive transfer). Herein, we aimed to determine the efficacy of EMT, supplemented by a metacognitive module, for veterinary students learning blood smear preparation and interpretation. Our hypothesis was that EMT and metacognition are associated with improved adaptive transfer performance, as compared with error avoidance training (EAT). A total of 26 students were prospectively enrolled in this double-blind study. Performance was evaluated according to monolayer area, smear quality, cell identification, calculated white blood cell differential counts, and overall application/interpretation. Students were trained with normal canine blood and static photomicrographs. Participants tested 72 hours after training demonstrated improved performance in a test that directly recapitulated training (Wilcoxon matched-pairs signed-rank test; two-tailed p all ≤ .001). There were no significant differences between EAT and EMT in this test (Mann–Whitney U test and Welch’s t-test; two-tailed p ≥ .26) or in short- and long-term adaptive transfer tests ( p ≥ .22). Survey data indicate that participants found errors to be a valuable element of training, and that many felt capable of accurately reflecting on their own performance. These data suggest that EMT might produce outcomes comparable to EAT as it relates to blood smear analysis.

Fixation and decalcification can alter protein structure in tissues, influencing the efficacy of primary antibodies routinely used in immunohistochemical (IHC) staining. Histologic examination of zebrafish requires both processes, making staining and analysis potentially challenging. Here, we investigated the effects of common fixation and decalcification protocols on IHC staining in zebrafish. We also identified zebrafish-reactive and -specific antibodies for use in research and diagnostics. For several of the antibodies, time spent in Dietrich's fixative containing 2% glacial acetic acid or 3.4% formaldehyde followed by decalcification with ethylenediaminetetraacetic acid (EDTA) significantly impacted IHC staining quality, particularly regarding staining intensity. Protocols utilizing shorter fixation times produced higher-quality stains. In addition, individual markers were variably affected by the type of fixative. Dietrich's fixative significantly reduced staining quality for the "neural" markers: glial fibrillar acidic protein, chromogranin A, S100. A negative time-dependent effect of fixation on staining quality was found for several antibodies: muscle actin (Dietrich's only), cytokeratin AE1/AE3, chromogranin, and S100. Neither decalcification protocol had a statistically significant negative time-dependent effect on staining quality. Based on our results, we suggest shorter fixation and decalcification protocols to best preserve IHC staining quality as well as recommend deliberate selection of the fixative used depending on the protein of interest.

Although errors can be a powerful impetus for learning, conventional pedagogy often emphasizes error-avoidance strategies that reward correct answers and disfavor mistakes. Error management training (EMT) takes an explicitly positive approach to errors, using them to create an active and self-directed learning environment. Using a surgical knot–tying model, we aimed to determine the efficacy of EMT among veterinary students with no prior surgical experience. We hypothesized that EMT would result in improved performance in unfamiliar scenarios (adaptive transfer) compared with an error-avoidance method. In this prospective double-blinded study, 42 students were equally divided between error avoidance training (EAT) and EMT groups. Performance in instrument- and hand-tied knots was evaluated for technique, time, number of attempts, and, when applicable, knot-leaking pressure. All participants demonstrated significant improvement between a pre-test and an analogous test 48 hours after training for all six outcomes (Wilcoxon matched pairs; two-tailed ps ≤ .013). An adaptive transfer test found no significant differences between EMT and EAT at 48 hours ( ps ≥ .053). All participants demonstrated a significant performance decline in six of eight outcomes at 7 weeks post-training ( ps ≤ .021). This decline was not significant for four of six EMT outcomes yet significant for five of six EAT outcomes. These data suggest that students trained in both EMT and EAT experience comparable gains in short-term performance, including adaptive transfer. Compared with EAT, EMT may help attenuate performance decline after a sustained period of quiescence. Educators may consider actively incorporating EMT into veterinary curricula.

An adult male Eurasian eagle owl (Bubo bubo) housed at a wildlife rehabilitation facility in southern Oregon died after a short period of progressive ill-thrift. Radiographs taken prior to death demonstrated abnormal radiopaque material in the coelom and the owl was submitted for postmortem examination. Black pigmented fungus was noted grossly, particularly in the respiratory tissues, with abundant oxalate crystal deposition associated with and without hyphal elements subsequently observed histologically. Aspergillus section Nigri was cultured from the lesions. Although there have been a few reports of aspergillosis caused by Aspergillus niger in avian species, the severity and wide tissue distribution of oxalates in this case are highly unusual.

Although quantitative assessment of margins is recommended for describing excision of cutaneous malignancies, there is poor understanding of limitations associated with this technique. We described and quantified histologic artifacts in inked margins and determined the association between artifacts and variance in histologic tumor-free margin (HTFM) measurements based on a novel grading scheme applied to 50 sections of normal canine skin and 56 radial margins taken from 15 different canine mast cell tumors (MCTs). Three broad categories of artifact were 1) tissue deformation at inked edges, 2) ink-associated artifacts, and 3) sectioning-associated artifacts. The most common artifacts in MCT margins were ink-associated artifacts, specifically ink absent from an edge (mean prevalence: 50%) and inappropriate ink coloring (mean: 45%). The prevalence of other artifacts in MCT skin was 4–50%. In MCT margins, frequency-adjusted kappa statistics found fair or better inter-rater reliability for 9 of 10 artifacts; intra-rater reliability was moderate or better in 9 of 10 artifacts. Digital HTFM measurements by 5 blinded pathologists had a median standard deviation (SD) of 1.9 mm (interquartile range: 0.8–3.6 mm; range: 0–6.2 mm). Intraclass correlation coefficients demonstrated good inter-pathologist reliability in HTFM measurement (κ = 0.81). Spearman rank correlation coefficients found negligible correlation between artifacts and HTFM SDs ( r ≤ 0.3). These data confirm that although histologic artifacts commonly occur in inked margin specimens, artifacts are not meaningfully associated with variation in HTFM measurements. Investigators can use the grading scheme presented herein to identify artifacts associated with tissue processing.