The role of L-asparaginase (L-ASP) in limiting signs of methotrexate (MTX) toxicosis was studied. Eight dogs were randomly allotted to 2 groups of 4 dogs. All dogs were given 400 IU of L-ASP/kg of body weight IM, on day 1. On day 10, group-1 dogs were given 3 mg of MTX/kg, IV, and group-2 dogs were given 6 mg of MTX/kg, IV. All dogs were given 400 IU of L-ASP/kg, IM, 24 hours later (on day 11). One group-2 dog was euthanatized on day 16 because of severe gastrointestinal signs that were unresponsive to treatment. A second dose of MTX, identical to that given on day 10, was given on day 20 to each surviving dog, followed by L-ASP on day 21. On day 67, the 7 surviving dogs were given 3 mg gf MTK/kg, IV. Adverse reactions observed were vomiting diarrhea, and weight loss. Gastrointestinal side effects of MTX were not attenuated with L-ASP and would be a serious limitation to use of MTX administered at an intermediate dose in the treatment of lymphoma in dogs.

We determined that the protein profiles of 14 isolates from animals with hemorrhagic septicemia were relatively homogeneous and could be placed in 2 distinct groups on the basis of their country of origin. Such differences correlated with the serotypic properties of the individual isolates; hemorrhagic septicemia isolates of Asian and North American origin (Carter B) had a major protein band with an apparent molecular mass of 32 kDa, whereas those of African origins (Carter E) had a major protein band with an apparent molecular mass of 37 kDa. The possession of a major 32-kDa protein band appeared to be unique to Carter B isolates, suggesting that electrophoresis may be a useful nonserologic technique for the identification of organisms of this serotype. Other major bands with apparent molecular masses of 27, 45, and 47 kDa were shared by all strains, regardless of their serotype. The lipopolysaccharides were of low molecular mass and relatively uniform from 1 isolate to the next.

The effect of pulsed radio frequency therapy (PRFT) was evaluated on seven ponies with no arthritis and in 28 ponies in which arthritis was created using intra-articular amphotericin B to induce synovitis in the right middle carpal joint. The ponies were divided into five treatment and two control groups. Two levels of arthritis were created and two dosage levels of PRFT were evaluated. The effect of PRFT on arthritic and nonarthritic joints was measured by comparing synovial fluid parameters, the degree and duration of lameness, the range of carpal motion, and carpus circumference, for treated and untreated groups. Lesions seen radiographically at gross pathology, and by histopathology were also compared between the treated and control groups. In the ponies with a mild form of induced arthritis, PRFT significantly (p < 0.05) reduced the severity and duration of lameness, swelling of the carpus, and the severity of gross pathological and radiographic changes. In these ponies the synovial acid phosphatase levels were lower, the mucin clot quality was superior, and the synovial protein levels were lower for the ponies receiving PRFT as compared to the arthritic ponies receiving no treatment. A dose response effect was evident. In ponies with a slightly more severe form of arthritis, PRFT was evaluated at one dosage level. The treated ponies were significantly improved over the untreated ponies with respect to carpal range of motion, degree of lameness, carpus swelling, and radiographic lesions. No deleterious effects were noted when normal, PRFT treated, middle carpal joints were compared to contralateral untreated, normal joints. It was concluded that significant beneficial effects resulted when affected ponies were treated with PRFT.

Mass screening ELISA methods were developed for testing cattle serum for antibodies against 14 common livestock diseases simultaneously. The absorbance values were transformed to a % ELISA (spectrophotometric antibody end point) by a computer interfaced with a microplate reader. A histogram indicating a cutoff point and a report for the veterinarian also was generated. The computer program produced a print-out of the antibody profile for each animal tested, the antibody concentration against each disease, and a histogram (antibody profile) showing the prevalence of each disease in the herd. Serum samples were obtained from 1,953 cattle, including 880 dairy cattle from 10 herds and 1,073 beef cattle from 20 herds. These samples were obtained from June 1988 through June 1989. The highest antibody prevalence was against bluetongue virus. Of the 1,953 cattle tested, 1,223 (63%) were seropositive for bluetongue virus, including 502 (57%) of the dairy cattle and 721 (67%) beef cattle. Other antibody prevalences, in descending order, were: rotavirus (44%), Pasteurella spp (25%), Leptospira spp and Haemophilus spp (22%), Mycoplasma spp (18%), parainfluenza virus (17%), Campylobacter spp (16%), Anaplasma marginale (15%), bovine leukosis virus (13%), Brucella spp (8%), Mycobacterium paratuberculosis (8%), bovine viral diarrhea virus (3%), and infectious bovine rhinotracheitis virus (3%). Major differences in antibody prevalence between dairy and beef cattle were that only 4% of the dairy cattle were seropositive for A marginale, compared with 25% of the beef cattle, and conversely, 29% of the dairy cattle were seropositive for bovine leukosis virus, compared with 1% of the beef cattle. Further development of the ELISA is advocated for mass screening of livestock sera for the application in epidemiologic methods for disease control in food animals.

A study was conducted to determine the immune (increased antibody) and protective (reduced colony-forming units) responses induced in mice by a: (i) single vaccinal inoculation, using various concentrations of Brucella cell surface protein (BCSP) or lipopolysaccharide (LPS); (ii) primary inoculation, using various concentrations of BCSP, followed by a secondary inoculation, using a standard concentration of BCSP; and (iii) primary inoculation, using 1 concentration of BCSP or LPS, followed by a secondary inoculation, using various concentrations of BCSP or LPS. Four weeks after the primary inoculation, mice were challenge exposed with approximately 1 X 10(4) colony-forming units of Brucella abortus strain 2308 and all mice were euthanatized at 6 weeks. Reduced splenic weights and reduced colony-forming units in the spleens of vaccinated mice, compared with nonvaccinated mice, were the criteria of protection. Increase in serum IgM and IgG was defined as immunity. Both BCSP and LPS induced protective and immune responses that were proportional to the dose given up to an optimal limit. However, concentrations higher than optimal decreased the protective and immune responses. This was true for mice given either 1 or 2 vaccinal inoculations. Enhanced secondary protective responses were seen only when suboptimal doses were used in the primary inoculation. Excessive or optimal doses in the secondary inoculations prevented or obscured the protectiveness and immunity by primary inoculations. The protective effects appeared to be additive when suboptimal doses were used in the primary and secondary inoculations. Inoculation of subimmunogenic doses induced a relative reduction in the antibody concentration after challenge exposure, compared with nonvaccinated mice. The overall results indicated that the protective responses induced by BCSP were probably attributable to LPS. The results also indicated a linear increase in protection and immune response corresponding to increasing doses up to an optimal dose, and this stoichiometric optimum may be achieved by the use of 1 or more vaccinal inoculations. However, once this optimum was obtained, additional amounts of BCSP or LPS cause perturbation of both the protective and serologic responses.

Concentrations of amino acids in the plasma of 13 neonatal foals with septicemia were compared with the concentrations of amino acids in the plasma of 13 age-matched neonatal foals without septicemia. Analysis of the results revealed significantly lower concentrations of arginine, citrulline, isoleucine, proline, threonine, and valine in the plasma of foals with septicemia. The ratio of the plasma concentrations of the branched chain amino acids (isoleucine, leucine, and valine) to the aromatic amino acids (phenylalanine and tyrosine), was also significantly lower in the foals with septicemia. In addition, the concentrations of alanine, glycine, and phenylalanine were significantly higher in the plasma of foals with septicemia. Therefore, neonatal foals with septicemia had significant differences in the concentrations of several amino acids in their plasma, compared with concentrations from healthy foals. These differences were compatible with protein calorie inadequacy and may be related to an alteration in the intake, production, use, or clearance of amino acids from the plasma pool in sepsis.

Twenty-three clinically normal Beagles were inoculated with North American Trypanosoma cruzi isolates from an opossum (Tc-O), an armadillo (Tc-A), or a dog (Te-D). The dogs were grouped according to the clinical outcome of inoculation. Group 1 consisted of 7 dogs inoculated with Tc-O or Tc-A that died or were euthanatized during acute stages of disease. Group 2 consisted of 5 dogs inoculated with Tc-O or Tc-A, that also developed acute disease, but survived to develop chronic disease. Group 3 consisted of 7 dogs inoculated with Tc-D neither developed acute nor chronic disease. Group 4 consisted of 4 dogs and served as noninoculated controls. In group 1, the gross lesions were diffusely pale myocardiums with right ventricular enlargement, hepatomegaly, and a moderate amount of modified transudate in the abdominal cavity. Severe diffuse granulomatous myocarditis with large numbers of pseudocysts and minimal fibrosis characterized the tissues from all cardiac chambers and septum. The lesions were most severe in the right atrium and ventricle. Mild multifocal myositis and pseudocysts were observed in skeletal muscles and smooth muscles of the urinary bladder and small intestine. Multifocal encephalitis and pseudocysts were in the cerebral cortex, cerebellum, and brain stem. In group 2, the gross lesions were biventricular enlargement and thinning of the ventricular free walls. The right ventricle contained the most severe microscopic changes. There were mild multifocal interstitial lymphohistiocytic cellular infiltrates, perivasculitis, and marked fibrosis in all areas of the myocardium. Mild myositis and multifocal encephalitis were seen in the skeletal muscles and brains. Pseudocysts were not observed in any tissues. In group 3, there was mild biventricular dilatation, minimal inflammation with fibrosis in cardiac tissues, and a multifocal myositis in most skeletal muscles. Multifocal encephalitis was seen in the brain stem. Pseudocysts were not observed in any tissues. Lesions were not found in group 4. Our results indicated heterogeneity between North American T cruzi isolates in lesion development in dogs, and there appeared to be a temporal relationship between acute and chronic trypanosomiasis in Tc-O- and Tc-A-inoculated dogs and the 3 phases of Chagas disease in human beings.

A survey of 1,965 equine colic cases was conducted from August 1985 to July 1986 at 10 equine referral centers located throughout the United States. The purpose of this study was to develop and validate a multivariable model for the need for surgery. Two-thirds of the cases were randomly selected for model development (1,336), whereas the remaining cases (629) were used only for subsequent validation of the model. If a lesion requiring surgical correction was found at either surgery or necropsy, the case for the horse was classified as surgical, otherwise the case was classified as medical. Only variables that were significant (P < 0.05) in an initial bivariable screening procedure were considered in the model development. Because of the large number of missing values in the data set, only variables for which there were < 400 missing values were considered in the multivariable analysis. A multivariable logistic regression model was constructed by use of a stepwise algorithm. The model used 640 cases and included variables: rectal findings, signs of abdominal pain, peripheral pulse strength, and abdominal sounds. The likelihood ratio for surgery was calculated for each horse in the validation data set, using the logistic regression equation. Using Bayes theorem, the posttest probability was calculated, using the likelihood ratio as the test odds and the prevalence of surgery cases (at each institution) as an estimate of the pretest odds. A Hosmer-Lemeshow goodness-of-fit X2 statistic indicated that the model fit the validation data set poorly, as demonstrated by the large X2 value of 26.7 (P < 0.001). However, when the expected proportion of surgical cases was compared with the observed proportion of surgical cases in each of 10 increments of risk, the model's performance appeared satisfactory.

Flow cytometric and conventional fluorescence microscopic methods were compared to detect heterologous (rabbit) neutrophil antibody bound to equine neutrophils. Unfixed and paraformaldehyde-fixed neutrophils were treated with normal rabbit serum or various dilutions of an antineutrophil serum. The cells were then reacted with fluorescein conjugates of goat anti-rabbit IgG, staphylococcal protein A, and streptococcal protein G. Antibody binding was evaluated by use of fluorescence microscopy and flow cytometry. Unfixed neutrophils treated with normal rabbit serum did not fluoresce, whereas many of the fixed neutrophils had distinct cytoplasmic and some membranous (nonspecific) fluorescence. Unfixed cells treated with the antiserum had localized areas (capping) of intense membrane fluorescence, whereas fixed cells had bright uniform membranous fluorescence. The intensity of specific fluorescence varied with the antiserum dilution and the conjugate. On flow cytometry, over 80% of unfixed cells treated with antiserum dilutions up to 1:1,024, 1:2,048, and 1:256 fluoresced, respectively, with anti-IgG, protein-G, and protein-A conjugates. Fixed cells generally had similar percentages of fluorescent cells, but at a higher (1-step) antiserum dilution. It was concluded that flow cytometry is more sensitive than conventional fluorescence microscopy to detect antibodies associated with equine neutrophils.

Twelve ponies were used to evaluate the reliability of an abdominal adhesion model and the efficacy of intraperitoneal infusion of sodium carboxymethylcellulose in preventing abdominal adhesions. A celiotomy was performed on each of the 12 ponies and the serosa of the distal portion of the jejunum was abraded with a dry gauze sponge at 5 locations. In addition to the serosal damage, a single 2-0 chromic gut suture was placed through the seromuscular layer of the jejunum in the center of the abraded area. After closure of the celiotomy, a 1% solution of sodium carboxymethylcellulose (7 ml/kg of body weight) was infused into the peritoneal cavity of 6 ponies. The other ponies served as untreated controls. All ponies were euthanatized 14 days after surgery. All ponies in the control group had abdominal adhesions at the time of necropsy. Four of the 6 ponies in the treatment group were free of adhesions. There was a significant (P < 0.0001) difference in the total number of adhesions between the 2 groups.