Effects on plasma endotoxin and eicosanoid concentrations and serum cytokine activities in horses competing in a 48-, 83-, or 159-km endurance ride under similar terrain and weather conditions

OBJECTIVE: To determine plasma endotoxin concentration in horses competing in a 48-, 83-, or 159-km endurance race and its importance with regard to physical, hematologic, or serum and plasma biochemical variables. ANIMAL: 3 horses. PROCEDURE: Weight and rectal temperature measurements and blood samples were obtained before, during, and after exercise. Blood samples were analyzed for plasma endotoxin concentration; serum antiendotoxin antibody titers; thromboxane B2 (TxB2) and 6-keto-prostaglandin F1alpha (PGF1alpha) concentrations; tumor necrosis factor alpha (TNFalpha) and interleukin-6 (IL-6) activities; WBC, plasma protein, lactate, serum electrolyte, and calcium concentrations; PCV; and creatine kinase activity. RESULTS: Detection of plasma endotoxin increased during exercise for horses competing at all distances but occurred more frequently in the 48- and 83-km groups. Plasma lactate concentration was significantly greater when endotoxin was concurrently detected. Endotoxin in plasma was not significantly associated with success of race completion. Plasma TxB2 and PGF1alpha concentrations and serum IL-6 activity significantly increased with exercise. Horses that had an excellent fitness level (as perceived by their owners) had greater decreases in serum antiendotoxin antibody titers during exercise than did horses perceived as less fit. In horses with better finish times, TxB2 and PGF1alpha concentrations were significantly greater and TNFalpha activity was significantly less than that of slower horses. CONCLUSIONS AND CLINICAL RELEVANCE: Endotoxemia developed during endurance racing, but was significantly correlated with increased plasma lactate concentration and not with other variables indicative of endotoxemia. Plasma TxB2 and PGF1alpha concentrations and serum TNFalpha activity may be associated with performance success.     

Use of a hydroxyapatite orbital implant in a cosmetic corneoscleral prosthesis after enucleation in a horse

A hydroxyapatite orbital implant was used after enucleation of an eye from a 5-year-old performance horse. A custom-made corneoscleral prosthesis was made and fitted over the hydroxyapatite implant. The implant and surgery were well tolerated. Placement of a cosmetic prosthesis is desired after enucleation of equine eyes to allow horses to return to competition. Synthetic spheres consisting of methylmethacrylate or silicone have been used, although reported complications have included extrusion, infection, and poor cosmetic results. Hydroxyapatite orbital implants made from marine coral allow vascular and fibrous tissue growth from the host orbit into the implant, which decreases the possibility of implant extrusion or infection and allows enhanced healing of defects in the overlying conjunctiva. Extraocular muscle fixation onto the implant permits motility and assists in the prevention of implant extrusion.     

Effects of storage time and temperature on pH,specific gravity,and crystal formation in urine samples from dogs and cats

OBJECTIVE: To determine effects of storage temperature and time on pH and specific gravity of and number and size of crystals in urine samples from dogs and cats. DESIGN: Randomized complete block design. ANIMALS: 31 dogs and 8 cats. PROCEDURE: Aliquots of each urine sample were analyzed within 60 minutes of collection or after storage at room or refrigeration temperatures (20 vs 6 degrees C [68 vs 43 degrees F]) for 6 or 24 hours. RESULTS: Crystals formed in samples from 11 of 39 (28%) animals. Calcium oxalate (CaOx) crystals formed in vitro in samples from 1 cat and 8 dogs. Magnesium ammonium phosphate (MAP) crystals formed in vitro in samples from 2 dogs. Compared with aliquots stored at room temperature, refrigeration increased the number and size of crystals that formed in vitro; however, the increase in number and size of MAP crystals in stored urine samples was not significant. Increased storage time and decreased storage temperature were associated with a significant increase in number of CaOx crystals formed. Greater numbers of crystals formed in urine aliquots stored for 24 hours than in aliquots stored for 6 hours. Storage time and temperature did not have a significant effect on pH or specific gravity. CONCLUSIONS AND CLINICAL RELEVANCE: Urine samples should be analyzed within 60 minutes of collection to minimize temperature- and time-dependent effects on in vitro crystal formation. Presence of crystals observed in stored samples should be validated by reevaluation of fresh urine.     

Characterizing avian Escherichia coli isolates with multiplex polymerase chain reaction

Colibacillosis caused by Escherichia coli infections account for significant morbidity and mortality in the poultry industry. Yet, despite the importance of colibacillosis, much about the virulence mechanisms employed by avian E. coli remains unknown. In recent years several genes have been linked to avian E. coli virulence, many of which reside on a large transmissible plasmid. In the present study, a multiplex polymerase chain reaction (PCR) protocol to detect the presence of four of these genes is described. Such a protocol may supplement current diagnostic schemes and provide a rapid means of characterizing the E. coli causing disease in poultry. The targets of this procedure included iss, the increased serum survival gene; tsh, the temperature sensitive hemagglutinin gene; cvi, the ColV immunity gene; and iucC, a gene of the aerobactin operon. Organisms, known for their possession or lack of these genes, were used as a source of the template DNA to develop the multiplex PCR protocol. Identity of the amplicons was confirmed by size, DNA:DNA hybridization with specific gene probes, and DNA sequencing. When the multiplex PCR protocol was used to characterize 10 E. coli isolates incriminated in avian colibacillosis and 10 from the feces of apparently healthy birds, nine of the isolates from apparently healthy birds contained no more than one gene, while the 10th contained all four. Also, eight of the isolates incriminated in colibacillosis contained three or more genes, while the remaining two contained two of the target genes. Interestingly, the isolates of sick birds containing only two of the targeted genes killed the least number of embryos,and the isolate of healthy birds that contained all the genes killed the most embryos amongthis group. These genes were not found among the non-E. coli isolates tested, demonstrating the procedure's specificity for E. coli. Overall, these results suggest that this protocol might be useful in characterization and study of avian E. coli.     

Real-time polymerase chain reaction testing for the detection of Mycobacterium genavense and Mycobacterium avium complex species in avian samples

Diagnosis of avian mycobacteriosis, caused by Mycobacterium genavense or species belonging to the Mycobacterium avium complex (MAC), is problematic. Polymerase chain reaction (PCR) offers rapid and sensitive detection of minute quantities of DNA, and conventional protocols have been used for evaluating avian specimens. The recent development of real-time PCR offers several advantages over conventional PCR. In attempts to improve diagnosing avian mycobacteriosis, a real-time TaqMan PCR assay was developed targeting the 65-kD heat shock protein gene of M. genavense and MAC spp. Nineteen reference isolates, 16 clinical isolates, and 32 avian tissue samples were used to evaluate the assay. When sufficient amplicons were produced, the species of mycobacteria was determined by standard sequencing of TaqMan PCR products and compared with results from commercial mycobacteriology laboratories and/or standard sequencing of conventional PCR products. The TaqMan PCR detected DNA from reference isolates of M. genavense, MAC spp., and Mycobacterium tuberculosis complex spp. Of the clinical isolates, the TaqMan PCR detected DNA from 10 of 12 Mycobacterium avium avium isolates and two of three Mycobacterium avium intracellulare isolates. For the tissue samples, the TaqMan PCR amplified DNA in six of nine samples that were identified by sequencing of conventional PCR products and/or by commercial mycobacteriology laboratories as being MAC spp. positive and three of four samples that were positive for M. genavense. There was some disagreement between speciation results from the TaqMan PCR and those from commercial mycobacteriology laboratories or conventional PCR or both. This disagreement was suspected to be because of relatively small numbers of base pairs in the TaqMan PCR products. The TaqMan PCR may provide a useful tool for evaluating clinical samples for DNA from mycobacteria species that most commonly infect birds; however, further refinement is needed in order to improve sensitivity and provide more accurate speciation.     

Strain specificity of the immune response of pigs following vaccination with various strains of porcine reproductive and respiratory syndrome virus

The primary objective of the study was to determine strain specificity of the immune response of pigs following vaccination with selected strains of porcine reproductive and respiratory syndrome virus (PRRSV). The experimental design included five groups (I through V, six pigs per group) free of antibody for PRRSV at the beginning of the experiment (day 0). On day 0, groups III, IV, and V were vaccinated with attenuated versions of PRRSV strains 8, 9, and 14, respectively. On day 21, the immunity of group II (non-vaccinated/challenged controls) and groups III, IV, and V was challenged by exposing each pig to a composite of the virulent versions of these same three strains. On day 35, all pigs, including non-vaccinated/non-challenged pigs of group I, were necropsied. Lungs and selected lymph nodes were examined for lesions. Serum samples obtained at weekly intervals throughout the study and lung lavage fluids obtained at necropsy were tested for the presence of PRRSV and its strain identity. Before challenge the strain of PRRSV identified in the sera of vaccinated pigs was always that with which the particular pig had been vaccinated (i.e. homologous strain), whereas, with one exception, only heterologous strains were identified after challenge. This apparent strain exclusion as a result of vaccination was statistically significant (P = 0.004). The tendency for heterologous strains to predominate after challenge suggests that a pig's immune response to PRRSV has some degree of strain specificity. Whether this finding has any clinical relevance in regard to immunoprophylaxis remains to be determined.     

Effect of anticonvulsant dosages of potassium bromide on thyroid function and morphology in dogs

A placebo-controlled experiment was performed to evaluate the effect of potassium bromide on the canine thyroid gland. Basal total thyroxine, free thyroxine, and basal thyrotropin serum concentrations were evaluated over a 6-month period in potassium bromide-treated and control dogs. A thyrotropin-releasing hormone stimulation test was also performed in all dogs at the beginning and conclusion of the study. Thyroid histopathology was compared between treated and control dogs at the end of the study. No difference was detected in any parameter between the two groups at the end of the study. A decline in thyroid hormone concentrations over the course of the study did occur in both groups of dogs. Potassium bromide does not appear to have a significant effect on canine thyroid function or morphology.     

A comparison of owner management and complications in 67 cats with esophagostomy and percutaneous endoscopic gastrostomy feeding tubes

Esophagostomy feeding tubes were placed in 46 cats. Percutaneous endoscopic gastrostomy (PEG) feeding tubes were placed in 21 cats. Owner management and complications and facility of use were evaluated retrospectively by review of medical records and owner survey. Both tube types were equally effective for maintenance of body weight, ease of owner management, and complication rates. All of 12 owners surveyed were comfortable with PEG tube management. Ninety-six percent of 24 owners surveyed were comfortable with esophagostomy tube management. The esophagostomy tube can be placed less invasively, without specialized equipment, making it an excellent alternative to the PEG tube.