A 3-year prospective study of large-breed dogs (4 months to 3 years of age) was conducted to evaluate the influence of radiographic positioning and age on coxofemoral joint (hip) laxity, subjective hip score, and development of degenerative joint disease (DJD). The dogs (n = 142) were breeder- or client-owned and represented 14 breeds. With dogs under heavy sedation, hips were radiographed in the standard hip-extended position and in the new compression/distraction position at 4, 6, 12, 24, and 36 months of age. The standard hip-extended radiographic view was evaluated by 3 methods: subjective evaluation by a board-certified veterinary radiologist (WHR), according to the standard 7-point Orthopedic Foundation for Animals (OFA) scoring scheme (OFA/WHR); joint laxity quantitation, using the Norberg angle (NA) method; and subjective scoring by a veterinary orthopedic surgeon for radiographic evidence of DJD. The hips in the distraction radiographic view were evaluated for passive hip laxity, as measured by use of a unitless distraction index (DI). Results of the study indicated that at a specific age (4, 6, 12, 24, or 36 months), all methods of hip evaluation correlated with each other at a moderate level (P < 0.05). The strength of contemporaneous correlation tended to increase with age of evaluation. Longitudinally, the between-method correlations were usually significant (P < 0.05), but not at a sufficiently high level to permit reliable between-method prediction. Prospective intraclass (within-method) statistical analysis of the various hip-scoring methods indicated that DI was superior to NA and OFA/WHR in comparability of score over time. The intraclass correlation coefficient ranged from 0.55 to 0.91 for DI in contrast to 0.40 to 0.78 for NA, and 0.06 to 0.39 for OFA/WHR over the age intervals of the study. For reference, the highest Kappa of 0.39 for the subjective OFA/WHR scoring reflected a maximal level of agreement between time intervals, only slightly better than chance. The associated large error questions the predictive use of the 7-point, subjective hip-scoring scheme, particularly prior to the age of 2 years.

Two distinct monoclonal antibodies (MAB) were prepared for testing with kidney, spleen, and retrobular tissue imprints made from chinook salmon (Oncorhynchus tshawytscha) affected with plasmacytoid leukemia (PL). Hybridomas were prepared from mice immunized with whole and lysed cells purified from renal or retrobular PL-positive tissues, which had been obtained from naturally and experimentally infected fish from British Columbia, Canada. The MAB reacted with at least 4 morphologically different cell types; fluorescence was associated with the plasma membrane and cytoplasm. The MAB also reacted with kidney imprints made from chinook salmon affected with a PL-like lymphoproliferative disease in California, indicating that these 2 diseases might be caused by a similar agent. The MAB did not react with any of the kidney or spleen imprints made from wild chinook salmon collected from a river in Ontario, Canada.

Intragastric pH monitoring was investigated in ponies. In cadaver stomachs, close contact with the mucosa led to high pH readings if nonweighted electrodes were used. However, pH recorded by weighted electrodes was markedly less affected by mucosal contact (P < 0.001). The latter were used for subsequent trials. In vivo, high correlations were found between pH recorded by weighted electrodes with or without a wire guard to prevent mucosal contact (correlation, r = 0.866; P < 0.001). Readings from each correlated well with those from simultaneous gastric aspirates (r = 0.774 and r = 0.807, respectively; P < 0.001 for both correlations). Plain electrodes recorded more highly variable (temporally heterogeneous) pH than did guarded electrodes. In vitro, trials using equine gastric fluid indicated that this resulted from greater responsiveness of the plain electrode. In vivo, episodes of nearly neutral pH were a common feature, and high pH correlated with intensely yellow-green, neutral fluid in the stomach (rank correlation, p = 0.626; P < 0.01). Concentration of bile acids did not correlate with pH or color score (p = -0.158 and p = 0.076, respectively). Causes of the episodes could include salivary influx, duodenogastric reflux, and variable gastric acid secretion. Pentagastrin infusion (0.6 micrograms/kg of body weight/ h) reduced intragastric pH (P = 0.018), but episodes of neutrality still occurred. Experiments in fed ponies indicated possible existence of a stable pH gradient, from neutral dorsally to heterogeneous and more acidic ventrally. Care was required in the rational choice of summary variables for expression of monitored pH data. Of the frequency distributions of 3 summary variables assessed in this study (mean, median, and percentage of data > pH 4), only that of the mean approached normality. Thus, use of the mean may allow analysis by parametric statistical methods. Intragastric pH monitoring was found to be a useful technique. Episodes of increased pH were often identified. These may represent episodic duodenogastric reflux.

Bordetella avium is an important respiratory tract pathogen of turkeys. In common with other pathogenic bordetellae, B avium manifests a tissue tropism for cilia of the respiratory tract epithelium. To determine the molecular characteristics of the host cell receptors for B avium, we used hemagglutination and in vivo adherence assays. Carbohydrates, mucus, sialic acid-specific lectin, and other glycoconjugates were evaluated for their ability to competitively inhibit binding of B avium to host cells. The gangliosides, GD(1a) and GT(1b), completely inhibited hemagglutination, whereas N-acetylneuraminic acid (sialic acid) partially inhibited hemagglutination. Adherence to turkey tracheal mucosa in vivo was significantly (P < 0.01) inhibited by GD(1a) and GT(1b) gangliosides, N-acetylneuraminic acid, bovine sub-maxillary mucin, and horseshoe crab (Limulus polyphemus) lectin. Treatment of the tracheal mucosa with neuraminidase also inhibited adherence of B avium. We conclude that N-acetylneuraminic acid and the gangliosides, GD(1a) and GT(1b) may be important components of the tracheal mucosa receptor for B avium in turkeys.

Procedures were developed to count neutrophils in milk using a flow cytometer. Milk samples from 2 experiments were counted: 1 with 4 noninfected cows and a second with 5 noninfected cows that were injected with endotoxin in 2 mammary quarters. Thus, the procedures were evaluated on normal milk and on that with high somatic cell count. Flow cytometric procedures involved fluorescence detection (from the dye carboxydimethylfluorescein diacetate) to distinguish intact and viable from fragmented cells, forward light scatter to detect cell size differences, and right-angle side scatter to detect cellular granularity. High fluorescence, large size, and high degree of granularity identified viable neutrophils. For all samples, neutrophils were also counted manually, using the cytologic centrifugation approach to create the slides; manual counts were used as the standard for comparison. In experiment 1 (normal milk), mean values for percentage of viable neutrophils estimated by manual and flow cytometry procedures agreed closely (26% vs 25.8% for foremilk and 28.8% vs 26.6% for bucket milk). Sources of variation in manual and flow cytometric estimates of percentage of neutrophils were examined. Cow variation was significant (P < 0.01) for manual and flow cytometric counts, but was larger for flow cytometric counts. Day-to-day variation in counts on milk from the same cow was negligible for manual counts, but was significant (P < 0.01) for flow cytometric counts. Coefficients of variation were considerably Larger for manual counts than for flow cytometry. In experiment 2 (milk with high cell count, foremilk), agreement between mean values obtained by flow cytometry and by manual counting was somewhat less. However, predicting manual percentage of neutrophils, using the flow cytometric estimate, had R2 of 0.77. Regression of the manual percentage of neutrophils value on the flow cytometric percentage of neutrophil value was close to 1.0, with only a small negative intercept. Some additional refinement of flow cytometric procedures may be required before flow cytometric estimates of percentage of neutrophils can be accepted without simultaneous validation by use of manual counting. In particular, causes of day-to-day variation in flow cytometric results should be identified and reduced.

The prevalence of feline leukemia virus (FeLV) antigen and DNA was assessed in formalin-fixed, paraffin-embedded tumor tissues from 70 cats with lymphosarcoma (LSA). Tissue sections were tested for FeLV gp70 antigen using avidinbiotin complex (ABC) immunohistochemistry (IHC); DNA was extracted and purified from the same tissue blocks for polymerase chain reaction (PCR) amplification of a 166 base pair region of the FeLV long terminal repeat (LTR). Results were related to antemortem FeLV enzyme-linked immunosorbent assay (ELISA) for serum p27 antigen, anatomic site of LSA, and patient age. Viral DNA was detected by PCR in 80% of cases and viral antigen by IHC in 57% of cases. Seventeen cases were PCR-positive and IHC-negative; one case was PCR-negative and IHC-positive. Clinical records included FeLV ELISA results for 30 of 70 cats. All 19 ELISA-positive cats were positive by PCR and IHC; of the 11 ELISA-negative cats that were negative by IHC, seven were positive by PCR. When evaluated according to anatomic site, FeLV DNA and antigen were detected less frequently in intestinal LSAs than in multicentric and mediastinal tumors. Lymphosarcoma tissues from cats < 7 yr were several fold more likely to be positive for FeLV antigen by IHC than were tumors from cats > or = 7 yr. However, there was no significant difference in PCR detection of FeLV provirus between LSAs from cats < 7 yr and those > or = 7 yr. These proviruspositive, antigen-negative cases may represent infection with latent or replication-defective FeLV.

Results of an ELISA, indirect fluorescent antibody (IFA) test, and immunoblot analysis (western blotting) for antibody to Borrelia burgdorferi in a sample of 216 lactating dairy cows were compared. The microscopic microtitration agglutination test for antibody to 6 serovars of Leptospira interrogans was also performed to evaluate possible cross-reactivity between B burgdorferi and L interrogans. Using western blotting as the standard test against which the ELISA and IFA test were compared, the ELISA had greater sensitivity (50% in summer and 38% in spring) with similar specificity (83 and 82%), compared with the IFA test (sensitivity, 6 and 5%; specificity, 90 and 83%). In addition, seropositivity to B burgdorferi, using the ELISA, was not found to be associated with seropositivity to L interrogans serovars. A matched case-control study evaluating the association between clinical lameness and antibody to B burgdorferi was performed in lactating dairy cows of 17 Minnesota and Wisconsin herds. Sera from case and control cows matched by herd, parity, and stage of lactation were evaluated, using an ELISA for B burgdorferi antibody during 2 seasons. High B burgdorferi antibody values were associated with clinical lameness in dairy cows (P = 0.006 in summer and P = 0.04 in spring).

Ground reaction force (GRF) patterns from 20 clinically sound Dutch Warmbloods were recorded at the right fore-leading canter, and a standard horse was composed. These GRF data for the standard can be used for evaluation of jumping horses. The GRF patterns were asymmetric for all 4 limbs. The leading right forelimb decelerated the body. The trailing left forelimb propelled the body and decelerated it slightly. The trailing left hind limb propelled, and the leading right hind limb contributed to deceleration and propulsion. Referred to the maximal vertical load of the leading right forelimb, the load of the trailing left forelimb was 25% more; the load of the right hind limb was slightly less, whereas the load of the left hind limb was about 80% of that value.

Current medical management of dogs with Portosystemic shunt (PSS) includes dietary protein restriction. After establishment of baseline values, 32 dogs underwent portosystemic anastomosis to induce PSS. They were assigned to 1 of 4 dietary treatments, and given 11 or 24% crude protein (CP); 20% of the protein was derived from branched chain or aromatic amino acids. The apparent digestibility of CP and of total digestible energy were not affected by PSS. The apparent digestibility of fat decreased from 92% to 85% in dogs with PSS (P < 0.01). Across all diets, the apparent dietary protein requirement (ADPR) was 2.07 g of CP/kg of body weight/d in clinically normal dogs and 2.11 g of CP/kg/d after PSS. Dietary amino acid composition had no effect on ADPR. The ADPR for dogs fed the 11% protein diets was 1.69 g of CP/kg/d in clinically normal dogs and 1.62 g of CP/kg/d after PSS, whereas the ADPR in dogs fed the 24% protein diets was 3.94 g of CP/kg/d before PSS and 3.31 g of CP/kg/d after PSS. Serum total protein, urea nitrogen, and albumin concentrations were lower in dogs with PSS fed the 11% protein diets, compared with those fed the 24% protein diets. We conclude that there is no difference in ADPR in dogs with PSS; however, the low protein intake of 1.62 g of CP/kg/d appeared inadequate to maintain normal protein stores. Dietary protein that provides at least 2.1 g of CP/kg/d is recommended for dogs with PSS.

Although feline immunodeficiency virus (FIV) and the unrelated retrovirus feline leukemia virus (FeLV) are associated with acquired immune deficiency in cats, experimental and field evidence indicates that coinfection with both viruses may lead to more serious disease syndrome. A third feline retrovirus, feline syncytium-forming virus (FeSFV), which is far more prevalent than either FIV or FeLV and is considered nonpathogenic in nature, is consistently coisolated from sick, FIV-infected cats. To determine the potential role of FeSFV in enhancement of FIV-mediated disease, persistent FeSFV infection was established in 14 of 24 nine-month-old cats. Four months later, half the FeSFV-infected and half the noninfected cats were inoculated with blood obtained from a cat persistently infected with the Petaluma strain of FIV. At postinoculation week 17, 1 male cat infected with only FIV died of bacterial bronchopneumonia that could have been attributed to FIV-induced acquired immune deficiency-like syndrome. However, none of the remaining cats had clinical illness, whether infected with either virus alone or coinfected with both viruses. As early as postinoculation week 6, decreases were observed in the CD4+ to CD8+ T-lymphocyte ratio of both groups of cats inoculated with FIV. Infection with FeSFV had no effect on the CD4, to CD8+ T-cell ratio. Mitogen stimulation assays and total WBC count were unaffected by FeSFV infection, although an increase in numbers of neutrophils from FeSFV-infected cats was consistent, especially when compared with the decrease observed after FIV infection. Overall, results of the study indicate that coinfection with FeSFV may not enhance progression of the FIV-induced early stages of disease and that the positive correlation between FeSFV and FIV-induced acquired immune deficiency-like syndrome is attributable to a common mode of transmission, rather than to a synergistic effect of coinfection.