Objective-To assess effects of exercise on a treadmill with changes in gastric volume and pH in the proximal portion of the stomach of horses. Animals-3 healthy adult horses. Procedure-A polyester bag of approximately 1,600 mL was placed into the proximal portion of the stomach of each horse via a nasogastric tube. Changes in bag volume, determined by an electronic barostat, were recorded before, during, and after a training session on a treadmill with and without prior withholding of food. In separate experiments, pH in the proximal portion of the stomach was continuously recorded during exercise for fed and food-withheld conditions. Finally, changes in intra-abdominal and intragastric pressure were simultaneously recorded during a training session. Results-Bag volume rapidly decreased to nearly zero during trotting and galloping. Conversely, a return to walking resulted in a sharp increase in volume and a return to pre-exercise values. Intragastric and intraabdominal pressures increased almost in parallel with walking, trotting, galloping, and galloping on a slope. Gastric pH decreased rapidly to < 4 at the beginning of walking, continued to decrease during trotting and galloping, and remained low until a return to walking. Conclusions and Clinical Relevance-Increased intra-abdominal pressure during intense exercise in horses causes gastric compression, pushing acidic contents into the proximal, squamous-lined region of the stomach. Increased duration of acid exposure directly related to daily duration of exercise may be the reason that squamous lesions tend to develop or worsen when horses are in intensive training programs.

Objective-To determine the effects of etodolac administration on results of thyroid function tests and concentrations of plasma proteins in clinically normal dogs. Animals-19 healthy random-source mixed-breed dogs. Procedure-Blood samples for measurement of serum thyroxine (T4), 3,5,3'-triiodothyronine (T3), free T4 (fT4), and endogenous canine thyroid stimulating hormone (cTSH) were measured twice before as well as on days 14 and 28 of etodolac administration (mean dosage, 13.7 mg/kg, PO, q 24 h). Plasma total protein, albumin, and globulin concentrations and serum osmolality were measured once before as well as on days 14 and 28 of etodolac administration. Results-Etodolac administration did not significantly affect serum T4, T3, fT4, or cTSH concentrations or serum osmolality. Significant decreases in plasma total protein, albumin, and globulin concentrations were detected on days 14 and 28 of administration. Conclusions and Clinical Relevance-Results of thyroid function tests are not altered when etodolac is administered for up to 4 weeks. Therefore, interpretation of results of these tests should accurately reflect thyroid function during etodolac treatment. Plasma total protein, albumin, or globulin concentrations that are less than the respective reference range in a dog administered etodolac for greater than 2 weeks may be an effect of treatment rather than an unrelated disease process. A decrease in plasma protein concentrations may reflect subclinical injury of the gastrointestinal tract.

Objective-To determine total glutathione (GSH) and glutathione disulfide (GSSG) concentrations in liver tissues from dogs and cats with spontaneous liver disease. Sample Population-Liver biopsy specimens from 63 dogs and 20 cats with liver disease and 12 healthy dogs and 15 healthy cats. Procedure-GSH was measured by use of an enzymatic method; GSSG was measured after 2-vinylpyridine extraction of reduced GSH. Concentrations were expressed by use of wet liver weight and concentration of tissue protein and DNA. Results-Disorders included necroinflammatory liver diseases (24 dogs, 10 cats), extrahepatic bile duct obstruction (8 dogs, 3 cats), vacuolar hepatopathy (16 dogs), hepatic lipidosis (4 cats), portosystemic vascular anomalies (15 dogs), and hepatic lymphosarcoma (3 cats). Significantly higher liver GSH and protein concentrations and a lower tissue DNA concentration and ratio of reduced GSH-to-GSSG were found in healthy cats, compared with healthy dogs. Of 63 dogs and 20 cats with liver disease, 22 and 14 had low liver concentrations of GSH (µmol) per gram of tissue; 10 and 10 had low liver concentrations of GSH (nmol) per milligram of tissue protein; and 26 and 18 had low liver concentrations of GSH (nmol) per microgram of tissue DNA, respectively. Low liver tissue concentrations of GSH were found in cats with necroinflammatory liver disease and hepatic lipidosis. Low liver concentrations of GSH per microgram of tissue DNA were found in dogs with necroinflammatory liver disease and cats with necroinflammatory liver disease, extrahepatic bile duct occlusion, and hepatic lipidosis. Conclusions and Clinical Relevance-Low GSH values are common in necroinflammatory liver disorders, extrahepatic bile duct occlusion, and feline hepatic lipidosis. Cats may have higher risk than dogs for low liver GSH concentrations.

Objective-To characterize matrix metalloproteinase (MMP)-2 and -9 in CSF of clinically normal dogs. Sample Population-Samples of CSF collected from 23 dogs. Procedure-Dogs were anesthetized, CSF samples were collected, and dogs were then euthanatized. Each CSF sample was evaluated immediately for RBC count, WBC count, and protein and glucose concentrations, and cytologic examination also was performed. Samples were considered normal when protein concentration was < 25 mg/dL and CSF contained < 6 WBCs/μL and < 25 RBCs/μL. Samples were stored at -70°C. Sections of brain tissue were collected and processed for histologic examination. The MMPs were evaluated by use of gelatin zymography and a polyclonal antibody-based sandwich ELISA. Results-Mean WBC count for CSF samples was < 1 WBC/μL (range, 0 to 3 WBCs/mL). Mean protein concentration was 12 mg/dL (range, 8 to 17 mg/dL). Mean RBC count was 3.65 RBCs/μL (range, 0 to 21 RBCs/μL). All CSF samples generated a clear band on zymography gels that corresponded to the human commercial standard of proenzyme MMP-2. Other major clear bands were not detected on zymography gels. Bands correlating to MMP-9 were not detected in any samples. The ELISA results revealed a mean +/- SD proenzyme MMP-2 concentration of 5.61 +/- 1.92 ng/mL (range, 3.36 to 10.83 ng/mL). Conclusions and Clinical Relevance-The proenzyme form of MMP-2 is detectable in CSF of clinically normal dogs, whereas MMP-9 is not detectable. Additional investigation of MMPs in CSF from dogs with various diseases of the nervous system is indicated.

Objective-To use antibodies produced by calves in response to infection with Mannheimia haemolytica in immunoaffinity chromatography for the identification and subsequent isolation of the dominant immunogenic antigens from bacteria grown in irondeficient media. Sample Population-Serum from 10 calves actively infected with M haemolytica. Procedure-An outer membrane protein fraction was obtained from sonicated salt-extracted M haemolytica cells by extraction with N-lauroyl sarcosinate. The immunoglobulin fraction of serum from calves actively infected with M haemolytica was used to prepare an immunoaffinity column. The immunoaffinity column was used to isolate the dominant immunogenic proteins from the outer membrane protein fraction. The resultant immunogenic protein fraction was subjected to ELISA and immunoblot methods as well as carbohydrate quantification. Sequencing of the N-terminal was performed on the most prominent protein. Results-5 immunogenic proteins with molecular weights of 42, 30, 24, 20, and 15 kd were isolated. The immunogenic protein fraction was found to contain 51% carbohydrate. The immunoaffinity column capacity was 1 µg of immunogenic protein/mL of gel. The N-terminal sequence of the 42-kd protein was Tyr-Gln-Thr-Tyr-Gln-Ser-X-Leu-Gln, where X could not be identified. Conclusions and Clinical Relevance-Immunogenic proteins were isolated by use of immunoaffinity chromatography. A substantial amount of carbohydrates was co-purified in the process. Additional experiments are needed to determine whether the carbohydrates would hinder or enhance development of vaccine preparations. This method could potentially allow a more rapid production of antigens for use in vaccines.

Objective-To provide an epidemiologic investigation of the seroprevalence of antibodies to Toxoplasma gondii in populations of cats and wild rodents in Rhode Island and to address the possible epidemiologic role of wild rodents in the spread of toxoplasmosis. Animals-200 cats and 756 small wild rodents. Procedure-Serum samples were obtained from 84 cats in animal shelters and 116 cats in veterinary hospitals. Serum samples were also obtained from 756 small wild rodents from multiple sites in Rhode Island. Sera from rodents and cats were assayed for antibodies to T gondii by use of the modified agglutination test Results-Overall, 42% (84/200) of cats had serum antibodies to T gondii. Seroprevalence was not significantly different between stray (50%; 42 /84) versus client-owned (36%; 42/116) cats, between male (43%; 40/94) versus female (42%; 39/93) cats, or between indoor (26%; 7/27) versus outdoor (39%; 35/89) cats. Seroprevalence rate of trapped rodents was 0.8% (6/756). Six rodents captured in Washington County accounted for of the seropositive rodents. Four of 6 of the seropositive rodents were trapped at a single site in Washington County (an abandoned barn). Five stray cats, known to have resided at the same site in Washington County as 4 of the seropositive rodents, were also found to be seropositive for antibodies to T gondii. Conclusions and Clinical Relevance-Seroprevalence rate in rodents was not correlated with the seroprevalence rate in cats. Stray cats, especially those known to be feral, may be more likely to perpetuate the cat-mouse cycle of T gondii than clientowned cats.

Objective-To evaluate efficacy and safety of IP administration of high-molecular-weight carboxymethylcellulose (HMW CMC) for the prevention of postoperative intra-abdominal adhesions in ponies. Animals-10 ponies. Procedure-A 1% solution of HMW CMC was instilled intra-abdominally prior to surgery in 5 ponies, whereas 5 control ponies did not receive HMW CMC. Postoperative adhesions were induced by use of a bowel-abrasion method comprising laparotomy, typhlotomy, and abrasion of jejunal serosa at multiple sites with placement of 3 sutures at each site. Day of surgery was day 0. After surgery, ponies were monitored, and hematologic, serum biochemical, and peritoneal fluid analyses were performed on days 1, 2, 3, 5, 7, and 10. On day 10, ponies were euthanatized. Intra-abdominal adhesions were recorded, and tissue samples were collected for histologic examination. Results-A significantly greater number of adhesions, number of multiple adhesions, and mean incidence of adhesions were identified in control ponies, compared with CMC-treated ponies. Mean peritoneal fluid WBC count on day 7 and serum fibrinogen concentrations on days 5 and 7 were significantly higher in control ponies, compared with CMC-treated ponies. Results of serum biochemical analyses did not differ significantly between the 2 groups. Conclusions and Clinical Relevance-Intra-abdominal use of 1% HMW CMC during surgery was effective for preventing postoperative adhesions in ponies. Use of HMW CMC did not have detrimental effects on wound healing, intra-abdominal defenses, or patient health. A 1% solution of HMW CMC may be used routinely during abdominal surgery of horses for prevention of postoperative adhesions.

Objective-To establish an immortalized cell line and transplantable xenograft of feline bronchioloalveolar lung carcinoma (BAC). Sample Population-Pleural effusion from a 12-yearold Persian male cat with BAC. Procedure-Tumor cells from the pleural effusion were grown in monolayer cell culture and injected into severe combined immunodeficient (SCID) mice to establish an immortalized cell line as well as a transplantable xenograft. Results-Both the primary lung carcinoma, the derived cell line, and the transplantable xenograft had evidence of a type-II pneumocyte origin expressing lamellar bodies ultrastructurally and thyroid transcription factor-1 and surfactant immunocytochemically. All 3 also expressed nuclear p53 immunoreactivity. A metaphase spread of the cell line (SPARKY) probed with fluorescein-labeled genomic feline DNA gave evidence of its feline origin. Flow cytometric studies indicated aneuploidy with a DNA index of 1.6. An R-banded karyotype revealed a modal number of 66 including the feline Y chromosome. The cell line had a doubling time of 16 hours. The xenograft (SPARKY-X) reached a diameter of 1 cm in 3 weeks in SCID mice. Deoxyribonucleic acid fingerprint analysis revealed that SPARKY and SPARKY-X were novel and strongly matched each other, except for the murine component found in SPARKY-X. Interestingly, SPARKY-X manifested the characteristic lepidic growth pattern of pulmonic BAC. Conclusions-Both the cell line and xenograft retained their autochthonous BAC phenotype, making them useful for the subsequent dissection of molecular abnormalities in feline BAC and in vitro screening of chemotherapeutic agents.

Objective-To evaluate the effect of 2 cyclooxygenase (COX)-2 inhibitors on contractile activity of the circular smooth muscle layer of the equine dorsal and ventral colon. Sample Population-Samples of the dorsal and ventral colon obtained from 10 healthy horses. Procedure-Full-thickness tissue samples were collected from the dorsal colon in the area of the diaphragmatic flexure and the ventral colon in the area of the sternal flexure. Samples were cut into strips oriented along the fibers of the circular muscle layer and mounted in a tissue bath system for determination of contractile strength. Incremental amounts of etodolac, nabumetone, and indomethacin ere added, and contractile activity was recorded. Results-Response of the dorsal and ventral colon to nonsteroidal anti-inflammatory drugs (NSAIDs) was variable. Indomethacin induced the greatest reduction in contractile activity, followed by nabumetone. For etodolac, the difference from baseline values was only significantly reduced at the highest concentration used (1 × 10(-5)M) for the ventral colon. Conclusions and Clinical Relevance-The NSAIDs that are designed to target the COX-2 isoform appeared to have variable effects on the contractile activity of the equine dorsal and ventral colon. Etodolac appeared to have the least effect on contractile activity, compared with the effects attributable to nabumetone, and would potentially have the fewest adverse effects relative to motility of the dorsal and ventral colon.

Objective-To evaluate the effect of prolonged water exposure on tissue mass and solutes of outer and inner layers of the stratum medium, sole, frog, and the stratum medium (SMZA) zona alba layer of horses' hooves. Specimen Population-10 hooves from 10 horses without foot abnormalities. Procedure-Hoof wall tissue specimens were obtained and immersed for 10 days in distilled deionized water. Serial changes in mass were recorded during the immersion period. Subsequently, osmolarity and Na+, K+, Cl-, and protein concentrations of the immersion solution were quantified. Results-Fully cornified outer hoof wall, sole, and frog epidermal structures increased in mass, whereas the SMZA lost mass when immersed in water. All hoof structures had a variable loss of crystalloids during immersion, but none of the specimens lost proteins. The frog epidermis was distinct in that total solute lost during immersion could not be ascribed to Na+, K+, and Cl-. Conclusions and Clinical Relevance-Data support a 2-compartment model for the fully cornified outer stratum medium, frog, and sole that permits the exchange of crystalloids, but not proteins, across the cell membrane and infers that topical agents containing proteins cannot benefit the hoof. The unique osmotic behavior of the SMZA relative to other hoof structures suggests the hypothesis that it is composed of transitional epithelial cells. The solutes lost from frog epithelium are interpreted to reflect its unique lipid composition.