Serological tests were performed on 380 cats with necropsy-confirmed heartworm status to compare the performance of currently available commercial laboratory and point-of-care heart-worm serological tests in an heartworm-endemic area. Overall, antigen tests detected 79.3% to 86.2% of heartworm infections and were highly specific. Most cats with false-negative antigen tests had a single male worm. Antibody tests detected 62.1% to 72.4% of heartworm infections and had a wider range of false-positive results (1.4% to 19.1%) than antigen tests (0.3% to 2.0%). Serological tests for feline heartworm infection varied in diagnostic performance. Combining results from antigen and antibody tests achieved greater sensitivity than using either test alone.
Reference: Berdoulay et al, JAAHA 40:376-384, 2004.

Hematological parameters, plasma C-reactive protein (CRP), and tumor necrosis factor were analyzed in 64 dogs with a presumptive diagnosis of pyometra. Final diagnosis (i.e., pyometra or cystic endometrial hyperplasia]) was determined by histopathology. As a single test, the percentage of band neutrophils had the highest sensitivity in the prediction of pyometra (sensitivity, 94%). The combination of percentage of bands and CRP had the highest sensitivity (97.7%; specificity, 75%) in predicting the presence of pyometra. The most common clinical signs noted in the study were vaginal discharge, polyuria, polydipsia, lethargy, and gastrointestinal signs. A combination of three or more of these clinical signs was significantly associated with pyometra.
Reference: Fransson et al, JAAHA 40:391-399, 2004.

The antigen-specific immune response to dietary proteins in 14 healthy domestic shorthair cats was characterized, and compared when those proteins were fed unprocessed or as part of a canned diet. The cats were fed 2 dietary proteins (soy and casein) either as unprocessed aqueous suspensions or as part of canned diets for 21 days. Serum IgG and IgA and salivary IgA were assayed by indirect ELISA, and antigen-specific proliferation of mesenteric lymph node-derived lymphocytes was determined. Robust serum IgG and IgA responses to dietary proteins were elicited, irrespective of the form in which they were fed. Salivary IgA responses to unprocessed proteins were not detected. However, a significant salivary IgA response to the protein isolated from the canned casein diet was observed in cats fed canned casein but not in those fed unprocessed casein. Lymphocyte proliferation to the antigens was slight, and there were no significant differences between groups. Results indicated that cats develop robust serum IgG and IgA responses to dietary proteins when fed as either aqueous suspensions or as part of canned diets. For certain proteins, there may be an increase and a qualitative difference in the immunogenicity of canned diets, compared with unprocessed proteins. Thus, canned diets may not be ideal for management of cats with enteritis.
Reference: Cave and Marks, AJVR 65: 1427-1433, 2004.

A retrospective study was performed on 200 randomly selected cases of inflammatory myopathy in dogs from diagnostic muscle biopsies received at the Comparative Neuromuscular Laboratory, Univ. of CA, San Diego. The most common clinical signs were generalized weakness, stilted gait, dysphagia, masticatory or generalized muscle atrophy, inability to open the jaw, megaesophagus, and dysphonia. Myalgia was rarely described. Age of onset ranged from 0.25 to 14 years, and genders were equally represented. Breed distribution approximated the 2002 AKC registration statistics (r = .85) with the notable exception of Boxers and Newfoundlands. Average creatine kinase and aspartate aminotransferase concentrations in generalized inflammatory myopathy cases were significantly higher than those with focal inflammatory myopathy (p < .05). Neoplasia developed in 12 of 200 dogs within 12 months of diagnosis of polymyositis, with lymphoma diagnosed in 6 of 32 Boxers. Inflammatory myopathy was associated with antibody titers against infectious diseases in 38 dogs. Neospora caninum and Hepatozoon americanum cysts were found in tissues of 2 dogs not serologically tested. Antibodies against an unidentified sarcolemmal antigen were found in 9 of 19 Newfoundlands with polymyositis. The spectrum of canine inflammatory myopathies can be broad, with infectious etiologies relatively common, and can include pre-neoplastic and uncharacterized syndromes.
Reference: Evans, Levesque, and Shelton. JVIM 18: 679-691, 2004.

The objective of this study was to determine whether transdermal methimazole was as safe and effective as oral methimazole for controlling hyperthyroidism in cats. Forty-seven cats with newly diagnosed hyperthyroidism were randomized to receive either transdermal methimazole in pluronic lecithin organogel, or oral methimazole (2.5 mg q12h for either route). Cats were evaluated at weeks 0, 2, and 4 with a physical exam, body weight, CBC, biochemical panel, urinalysis, measurement of total T4, indirect Doppler blood pressure determination, and completion of owner questionnaire. Data between the 2 groups and over time were compared by nonparametric methods. Forty-four cats followed the protocol (17 oral and 27 transdermal). Significantly more cats treated with oral methimazole had serum T4 concentrations within the reference range after 2 weeks (14 of 16 cats) compared to those treated by the transdermal route (14 of 25; p = .027). This difference was no longer significant by 4 weeks of treatment (9 of 11 for oral versus 14 of 21 for transdermal), possibly because of inadequate numbers evaluated by 4 weeks. Cats treated with oral methimazole had a higher incidence of gastrointestinal (GI) adverse effects (4 of 17 cats) compared to cats treated with transdermal methimazole (1 of 27; p = .04), but no differences were found between groups in the incidence of neutropenia, hepatotoxicity, or facial excoriations. Although the overall efficacy of transdermal methimazole is not as high as that of oral methimazole at 2 weeks of treatment, it is associated with fewer GI adverse effects compared to the oral route.
Reference: Sartor et al, JVIM 18: 651-655, 2004.