A murine hybridoma monoclonal antibody (MAB), IBF9, was generated by fusing myeloma cells (P3X63Ag8.653) with spleen cells from a BALB/c mouse immunized with the canine melanoma cell line CML-10c7. Initial screening of hybridoma antibodies was performed by use of an indirect immunoperomidase assay on formalin-fixed CML-10c7 cells. The isotype of MAB IBF9 was IgG1 as determined by radial gel immunodiffusion. The antibody was tested for reactivity against a panel of formalin-fixed, paraffin-embedded normal and neoplastic canine tissues, using immunoperoxidase staining. Immunostaining was observed in melanomas (24 of 38), a few carcinomas, basal cell tumors, and cutaneous lymphosarcomas. Immunostaining was not observed in fibrosarcomas, hemangiosarcomas, hemangiopericytomas, or histiocytomas. Staining of normal adult canine tissues was limited to a few epithehal tissues and a small percentage of lymphocytes. Fetal tissues were not reactive with MAB IBF9. There were statistically significant differences in frequency of reactivity among melanomas with regard to oral vs non-oral, malignant vs benign, and mitotic indices greater than or equal to 1 vs mitotic indices < 1. Differences were not significant when tumors were compared for degree of pigmentation or histologic type. On the basis of these findings, we suggest that MAB IBF9 may be of assistance in diagnosis of nonpigmented melanomas and in assessing the malignant potential of melanomas.

To evaluate the effect of diet on results obtained by use of 2 commercial test kits for detection of occult blood in feces, 5 dogs were fed 7 diets in randomized sequence. Dry and canned diets with various principal ingredients were evaluated. Each diet was offered twice over a 24-hour period, followed by a 36-hour nonfeeding period. Fecal specimens were collected twice daily, and tests for occult blood were performed within 12 hours. The dietary origin of fecal specimens was confirmed by use of colored markers fed with each diet, and was correlated with estimates of gastrointestinal tract transit time. A modified guaiac paper test and an ortho-tolidine tablet test were performed on each specimen. Of 59 specimens, 4 were positive for occult blood, using the ortho-tolidine tablet test. Three positive results were associated with a mutton-based canned diet, and 1 positive result was associated with a canned beef-based diet. Of 59 specimens, 11 were positive for occult blood, using the modified guaiac paper test. Four positive results were associated with the mutton diet, and 3 positive results were associated with the beef diet. Of the remaining 5 diets, 4 caused 1 positive reaction. Results were inconsistent with the null hypothesis that the distribution of positive occult blood test results is not affected by diet (P < 0.025), and indicate that diet can affect the specificity of peroxidase-based tests for detection of occult blood in canine feces. Diet modification prior to testing is recommended.

Two commercially available tests, an antigen-capture ELISA for use on fecal samples, and a peroral nylon string test for use in dogs, were compared with a zinc sulfate fecal concentration technique (ZSCT) for detection of giardiasis in dogs. Of 77 dogs and 164 fecal samples (from these dogs), 33 and 52, respectively were found to be Giardia-positive on the basis of results of the ZSCT. The ELISA gave false-negative results for 10 and 14% of ZSCT-positive dogs and fecal samples, respectively, and false-positive results (relative to the ZSCT test results) in 13 and 10% of ZSCT-positive dogs and fecal samples, respectively. Of the 18 string-tested dogs, 14 were positive by results of the ZSCT. Of the 4 dogs that were Giardia-negative by ZSCT, 2 were Giardia-positive by ELISA. Dogs were sedated and given water and metoclopramide to aid passage into the duodenum of the capsule containing a nylon string. Of the 21 string tests performed on the 18 dogs, only 5 strings reached the duodenum, and 0 of the 5 yielded positive results for Giardia sp. Because the string broke in 1 dog (leaving most in the gastrointestinal tract and, therefore, producing a risk of string foreign body) further string tests were not done.

Quantitative immunodiffusion in one dimension was performed in 6-mm Duran tubes containing a 1% Nobel agar solution and various dilutions of antisera. A series of dilutions of pure myoglobin in equine sera as well as plasma from horses with rhabdomyolysis were tested. Standard curves were prepared of the migration distance of the formed precipitate from the meniscus of the gel after 3, 6, 12, and 24 hours. The clearest line of precipitate was formed with a 1:20 dilution of antisera in agar. Standard curves were nonlinear and plasma myoglobin could be detected at 2 micrograms of myoglobin/ml or greater. The test was optimal, with an error of 5.6%, when read at 24 hours at approximately 25 C. Tubes with agar could be stored for 6 months at 4 C without affecting the accuracy of the test. The specificity of myoglobin for skeletal or cardiac muscle, and its rapid clearance from serum after muscle necrosis, make it ideally suited for evaluating acute muscle damage and for testing the susceptibility of horses for rhabdomyolysis following an exercise test.