Aflatoxin (AF)-contaminated and fumonisin B1 (FB1)-contaminated (culture material from Fusarium moniliforme) diets were fed singly and in combination to growing cross-bred barrows. Six barrows (3 replicates of 2 each; mean body weight, 17.5 kg) per group were fed: 0 mg of AF and 0 mg of FB1/kg of feed (control); 2.5 mg of AF/kg of feed; 100 mg of FB1/kg of feed; or 2.5 mg of AF plus 100 mg of FB1/kg of feed for 35 days. The effects on production performance, serum biochemical, hematologic, immunologic, and pathologic measurements were evaluated. Body weight, gain, and feed consumption were significantly (P < 0.05) decreased by AF and AF plus FB1 diets. The FB1 diet decreased feed consumption, and although body weight was numerically decreased, it was not statistically significant. Aflatoxin increased serum gamma-glutamyltransferase (GGT) activity and total iron concentration and decreased urea nitrogen concentration and unsaturated iron-binding capacity. The FB1-alone diet increased serum GGT activity, whereas the AF plus FB1 diet increased serum aspartate transaminase, cholinesterase, alkaline phosphatase, and GGT activities, increased RBC count, triglycerides, and total iron concentrations, and decreased unsaturated iron-binding capacity and urea nitrogen concentration. For the most part, the effects of the AF plus FB1 diet on body weight and hematologic measurements could be considered additive. However, the effect of the AF plus FB1 diet on cholinesterase and alkaline phosphatase activities was greater than additive and was a synergistic response. One pig in the FB1-diet group and 2 pigs in the combination-diet group died. Postmortem lesions in pigs of the FB1-diet group consisted of ascites and increased liver weight. Observations at necropsy for pigs of the AF plus FB1-diet group consisted of hydrothorax, ascites, pulmonary edema, gastric erosions and ulceration, and increased liver and spleen weights. The AF diet increased relative liver weight and resulted in liver that was pale, rubbery, and resistant to cutting. Histologic lesions consisted of hepatic necrosis or degeneration, or both, with variable degrees of bile duct proliferation in barrows of the AF-diet groups. Renal tubular nephrosis was observed in barrows of the FB1 diet group, but this was not consistent in the AF plus FB1-diet group. Cell-mediated immunity, as measured by mitogen-induced lymphoblastogenic stimulation index, was decreased in barrows of the AF and FB1-diet groups, and values in barrows given the combination diet were significantly decreased from those in barrows given the single toxin diets. It was concluded that AF and FB1 (from culture material), singly or in combination, can adversely affect clinical performance, serum biochemical, hematologic, and immunologic values and induce lesions in growing barrows. For most of the variables we evaluated under our study conditions and dosages of toxins, measurements were affected more by the combination diet than by either single toxin diet, and the toxic responses could be described as additive or more than additive, particularly for induction of liver disease.

Objective--To measure arterial and venous blood gas, coagulation, and fibrinolysis variables in blood from isolated segments of control and ischemic large colons for the purpose of identifying variables for rapid, indirect assessment of colonic mucosal injury. Design--Variables were determined at specific intervals during the 4-hour study (3 hours of ischemia and 1 hour of reperfusion). Animals--Seven clinically normal horses between 2 and 15 years old. Procedure--Horses underwent laparotomy and occlusion of the lumen and vasculature of the mid-portion of the pelvic flexure of the large colon. During ischemia of 1 randomly-chosen colonic segment, variables were measured to determine colonic mucosal damage and were compared with histologic scores of colonic biopsy specimens. Results--Significant (P < 0.05) differences from control values were observed over time for venous pH, Pco2, PO2, oxygen saturation, oxygen content, arteriovenous oxygen difference, and lactate and glucose concentrations. Mean histologic scores of biopsy specimens obtained from ischemic colons were significantly (P < 0.05) greater (indicating greater damage) than those from control colons, and increased significantly (P < 0.05) with duration of ischemia. Conclusions--Venous lactate, oxygen saturation, and PO2 values were the most significant predictors of the severity of histologic damage within the ischemic colons (R2 = 0.661). Clinical Relevance-Venous blood gas and lactate values in the large colon are good predictors of the amount of intestinal damage incurred during 3 hours of ischemia, and may be clinically useful for the rapid determination of colonic viability.

Objective-To evaluate the ability of bovine complement to kill a variety of field isolates and laboratory strains of Brucella abortus. Design-The experimental approach was to determine the sensitivity of B abortus isolates to killing by bovine serum, and to document the role of complement in brucellacidal activity. Sample population-Six laboratory isolates and 12 field isolates of B abortus were tested. Procedure-The ability of B abortus to survive exposure to undiluted bovine serum for 2 hours at 37 C was assessed. The role of complement in killing was determined by examining the ability of heat (56 C for 60 minutes) and cobra venom factor to obliterate the activity in serum, and by detecting binding of the ninth component of bovine complement to serum-sensitive target cells. Results-Isolates of B abortus that were resistant to the bactericidal activity of normal bovine serum were revealed. These included field isolates and laboratory strains. Furthermore, the study confirmed earlier reports that bovine serum-mediated killing of B abortus is caused by the complement cascade. Conclusions-Some isolates of B abortus, like other gram-negative bacteria, were resistant to complement-mediated killing. Resistance was associated with smooth colony morphology. Isolates lacking detectable O antigen were serum sensitive.

Administration of an N-lauroylsarcosine-derived outer membrane protein fraction of Pasteurella haemolytica A1 (SCI-1) induced a protective response in calves against intrathoracic challenge exposure with the homologous serovar. Outer membrane proteins from heterologous serovars, A6 and A9, induced partial protection that was associated with their respective similarities to serovar A1 in outer membrane protein profiles derived by use of sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Calves vaccinated with SCI preparations did not have detectable neutralizing antibody to P haemolytica A1 leukotoxin. Antibodies to whole-cell antigens, carbohydrate-protein subunit antigen, and SCI-1 were associated with resistance, which indicates that protein antigens shared among cell surface, carbohydrate-protein subunit, and SCI preparations are immunogenic and enhance resistance to experimental challenge exposure.

Microcystin and related toxic peptides produced by cyanobacteria (blue-green algae) are potent and selective inhibitors of protein phosphatases 1 and 2A. We adapted existing enzymatic techniques to analyze the liver of rainbow trout after oral administration of hepatotoxic cyanobacteria. Liver tissue was removed 3 and 12 hours after treatment, and phosphatase activity was determined in liver extracts, using a specific phosphoprotein substrate. In all samples from fish exposed to toxic cyanobacteria, phosphatase activity was suppressed, whereas the control enzyme, lactate dehydrogenase, present in the same liver extract, was not affected by cyanobacteria. Thus, experimental poisoning by hepatotoxic cyanobacteria resulted in an abnormally low ratio of phosphatase to lactate dehydrogenase activity in the liver extracts. These results indicate that specific inhibition of phosphatases 1 and 2A may provide a useful diagnostic tool to determine the early effects of cyanobacteria toxic peptides directly in liver samples from poisoned animals. Although this test was developed with rainbow trout, it should be possible to extend the analysis of liver phosphatase activity to other species, including sheep and cattle, which are frequently affected by hepatotoxic cyanobacteria.

We evaluated the pharmacokinetics of IV administered sodium heparin and the pharmacodynamic effect of heparin on lipoprotein lipase (LPL) activity Horses were allotted to 3 groups. Plasma samples were obtained from each horse before and at various times for 6 hours after heparin administration for determination of heparin concentration, LPL activity, and activated partial thromboplastin time (APTT). The disposition of heparin was dose dependent. The area under the plasma heparin concentration vs time curve (AUC) increased more than proportionally with dose, indicating that heparin elimination was nonlinear. Total clearance of heparin was similar after the 40 and 80 IU/kg of body weight dosages, averaging 0.45 and 0.36 IU/kg/min, respectively. However, after administration of the 120 IU/kg dose, clearance was significantly less than that after the 40 IU/kg dose. The half-life of heparin averaged 53, 70, and 136 minutes after 40, 80, and 120 IU/kg, respectively, with significant differences observed between the low and high doses. In contrast to heparin, the area under the plasma concentration vs time curve for LPL activity increased less than proportionally with dose. Maximal LPL activity observed was independent of dose, averaging 4.8 micromole of free fatty acids/ml/h. The APTT was significantly prolonged for 120 minutes after administration of the 40 IU/kg dose. Correlation coefficients for LPL activity vs either plasma heparin concentration or APTT were less than 0.7, indicating that neither laboratory measure can be used to accurately predict plasma LPL activity.

Bovine immunodeficiency virus (BIV), a lentivirus, is prevalent in dairy and beef cattle in southeastern United States and may be associated with a lymphoproliferative disease. The mode(s) of BIV transmission are undefined. Because artificial insemination is a common practice in dairy production, contaminated stud semen could serve as an important source of infection if the virus is harbored in seminal fluids. To evaluate this possibility, we procured 11 cryopreserved semen specimens from a stud semen repository. Leukocytes were purified from the specimens, and the leukocyte DNA was used as template in a polymerase chain reaction procedure that targeted a 235-base pair, highly conserved domain of the BIV pol gene. The target sequence was amplified from the seminal leukocyte DNA of 9 of the specimens (82%), and nucleotide sequencing confirmed the BIV specificity of the fragment. This finding provides evidence that stud bull semen may serve as an important reservoir of BIV, suggesting the possibility that artificial insemination of dairy cows may have a major role in transmission and wide-spread dissemination of this bovine lentivirus.

Toxoplasma gondii-specific IgA, IgM, and IgG were measured by ELISA in the serum and aqueous humor of 29 client-owned cats with indigenous aviates and 7 specific-pathogen-free cats tested sequentially for 20 weeks after inoculation with T. gondii. Local antibody production in aqueous humor was estimated by multiplying the aqueous humor-to-serum T gondii-specific antibody ratio by the serum-to-aqueous humor total IgG (C value) or IgG (C value) ratio. Evidence for local production of antibody in aqueous humor was defined as C value greater than 8 or CTC value greater than 1. Toxoplasma gondii-specific IgM CTC values, IgG CTC values, or IgA CTC values greater than 1 were detected in the aqueous humor of 18 of 29 (62.1%) client-owned cats with endogenous uveitis; 2 cats had IgA CTC values greater than 1 without detectable IgM or IgG in aqueous humor. Toxoplasma gondii-specific IgM was not detected in the aqueous humor of experimentally inoculated cats before or after inoculation. Immunoglobulin G C values greater than 8 were detected in all 7 experimentally inoculated cats and ranged from 10.4 to 145.5. Immunoglobulin G C values greater than 8 were first detected 4 to 8 weeks after T gondii inoculation and were undetectable by week 16 after inoculation. Immunoglobulin A C values greater than 8 were detected in 4 of 7 cats and ranged from 12.7 to 264.3. Immunoglobulin A C values greater than 8 were first detected 4 to 8 weeks after inoculation, and were detected in 2 cats during week 20 after inoculation. It was concluded that some cats infected with T gondii develop detectable concentrations of T gondii-specific IgA in aqueous humor.

By use of wire ropes as the transosseous component, an external skeletal fixator for the repair of long bone fractures in horses and cattle has been designed and tested in axial compression. Theoretical methods were used in the design process to size fixator components; however, our results suggest that conventional methods of analyzing the displacement of the transosseous component may not apply to wire ropes. Large pretensions in the wire ropes are necessary to obtain functional stiffnesses for fracture fixation. Therefore, a method was sought for terminating the ropes so that an appropriate pretension could be introduced into the rope through its interface with the fixator rings. Ropes were terminated by use of 5 methods and were tested in axial tension to failure. These methods included 3 copper sleeve arrangements, welded ends, and drum sockets. The drum sockets (57.6% of rope breaking strength) far exceeded the strengths provided by the copper sleeves (8.5 to 26.6%) and the welded ends (44.3%). Using the drum sockets, 5 rope configurations were assembled to the fixator, using wood blocks to simulate bones with a gap defect. The fixator was loaded in axial compression for each of the rope configurations, and stiffnesses were determined from measured axial displacement and applied load. The 4-ring fixator configuration, with 2 ropes at 60 degrees angular separation/ring, was the stiffest. In a worst case (gap) model, a mean axial compression load of 1,730 N was observed at 2 mm of displacement for a 4-ring fixator configuration. Our results suggest that, in less conservative scenarios where compression of the fracture surfaces can share limb loads, wire ropes may function well as the transosseous components of an external fixator.

Free, autogenous, full-thickness skin grafts were applied to 10 dogs; 5 dogs were given an iron chelator, deferoxamine-10% hydroxyethyl pentafraction starch (DEF-HES; 50 mg/kg of body weight, IV), and 5 dogs were given an equal volume of 10% hydroxyethyl pentafraction starch (HES) in 0.9% saline solution (5 ml/kg, IV). All dogs (DEF-HES/HBO- and HES/HBO-treated) were exposed to 60 minutes of hyperbaric oxygen (HBO) at 2 atmospheres absolute pressure twice daily for 10 days, beginning the day of surgery. The percentage of viable graft on day 10 was lower in HES/HBO-treated-dogs (mean +/- SD, 13.3 +/- 21.3%; median, 3.0%) than in DEF-HES/HBO-treated dogs (64.7 +/- 39.2%; 88.3%; P = 0.095, Mann-Whitney two-tailed test). There was a positive correlation between percentage of viable graft (on day 10) and percentage of haired skin on the graft site (on day 28) for all dogs (r = 0.91) and for HES/HBO-treated dogs (r = 0.97). The DEF-HES/HBO-treated dogs had less consistent correlation (r = 0.67). Perivascular aggregates of foamy cells were observed in the superficial and reticular portions of the dermis and in the subcutaneous tissue on both surfaces of the panniculus muscle in the graft sites of DEF-HES/HBO-treated dogs. These cells were also observed in the dermis, but not subcutaneous tissue of the control skin sections, and in some viscera of DEF-HES/HBO-treated dogs. Deferoxamine appears to attenuate the detrimental effect of HBO and HES on survival of free skin grafts. However, clinical use of HBO is not recommended as adjunct treatment for free skin grafts in dogs in the first 10 days after grafting. Administration of DEF-HES is not recommended because it has failed to improve the survival of free skin grafts, and the consequence of the cellular response seen in this study is undetermined.