Effects of extracorporeal shock wave therapy and radial pressure wave therapy on elasticity and microstructure of equine cortical bone

OBJECTIVE: To measure changes in the modulus of elasticity (E) and describe histologic findings after extracorporeal shock wave therapy and radial pressure wave therapy on equine cortical bone specimens. SAMPLE POPULATION: 16 bone specimens from the proximodorsal cortex of an equine third metacarpal or metatarsal bone. PROCEDURE: Baseline E was determined by the density (p) and unidirectional ultrasound transmission velocity (C) of each specimen according to the equation E = pC2. Eight specimens were treated with 500 pulses of 0.15 mJ/mm2 of extracorporeal shock wave therapy, and 8 specimens were treated with 500 pulses of 0.16 mJ/mm2of radial pressure wave therapy. After treatment, C was determined again. Four treatment sessions resulted in 2,000 pulses and 5 C measurements. The p of each sample was measured again. Mean post-treatment E was calculated for each group. Nondecalcified sections of all specimens were stained with toluidine blue or basic fuchsin for histologic evaluation. RESULTS: Overall treatment group effect was not significant for C or E. Final E was not different from baseline values for extracorporeal shock wave therapy and radial pressure wave therapy. No histologic changes could be attributed to either treatment modality. CONCLUSIONS AND CLINICAL RELEVANCE: Extracorporeal shock wave therapy and radial pressure wave therapy did not affect the material properties of equine bone at the energy and pulse values used in this study.     

Effects of infusion of adenosine triphosphate-magnesium chloride on cardiopulmonary and clinicopathologic variables, cytokine activity, and endothelin concentration in horses administered a low dose of endotoxin

OBJECTIVE: To evaluate systemic effects of i.v. infusion of ATP-MgCl2 subsequent to infusion of a low dose of endotoxin in horses. ANIMALS: 12 adult horses. PROCEDURE: Horses were administered endotoxin (lipopolysaccharide [LPS]) or saline (0.9% NaCl) solution i.v., during a 30-minute period. Immediately thereafter, horses in each group were infused i.v. with ATP-MgCl2 or saline solution. Two weeks later, horses were administered the opposite solution (LPS or saline solution), but it was followed by the same infusion as 2 weeks previously (ie, ATP-MgCl2 or saline solution). Cardiopulmonary and clinicopathologic variables, cytokine activity, and endothelin (ET) concentrations were recorded. RESULTS: IV infusion of ATP-MgCl2 after administration of a low dose of endotoxin failed to attenuate the cardiopulmonary, clinicopathologic, and cytokine alterations that develop secondary to endotoxin exposure. The combination of LPS and ATP-MgCl2 potentiated pulmonary hypertension, leukopenia, and neutropenia when compared with the combination of LPS and saline solution. The combination of LPS and ATP-MgCl2 resulted in thrombocytopenia. Endothelin concentration was increased in jugular venous and pulmonary arterial plasma in horses receiving LPS and ATP-MgCl2. Similar increases were not observed with LPS and saline solution. CONCLUSIONS AND CLINICAL RELEVANCE: Administration of ATP-MgCl2 did not protect horses from systemic effects of experimentally induced endotoxemia. Furthermore, the use of ATP-MgCl2 during endotoxemia may worsen the cardiopulmonary and clinicopathologic status of affected horses. Because ATP and other adenine nucleotides are released from cells during shock, their potential role in the development of hemodynamic derangements, leukocyte adherence, and coagulopathies during endotoxemic episodes warrants further investigation.     

Investigation of pulmonary deposition of a nebulized radiopharmaceutical agent in awake cats

OBJECTIVE: To determine whether conscious, unsedated cats will inhale a nebulized material administered via a facemask and whether this material will reach the lower airways. ANIMALS: 20 healthy adult cats. PROCEDURE: Technetium Tc 99m-diaminetriaminopentaacetic acid (99mTc-DTPA) was nebulized into a spacer and administered to the cats via a closely fitting facemask. By use of a gamma camera, images were then immediately obtained to determine the distribution of 99mTc-DTPA within the lower airways. RESULTS: Images obtained by use of the gamma camera revealed that all 20 cats had inhaled 99mTc-DTPA from the facemask. In each cat, deposition of the radiopharmaceutical agent was evident throughout the lung fields. CONCLUSIONS AND CLINICAL RELEVANCE: Awake cats that were not used to the application of a facemask did inhale substances from such a device. Aerosolization of medications may be a feasible route of administration for cats with lower airway disease.     

Idiopathic gastroesophageal reflux disease in an adult horse

Chronic gastroesophageal reflux disease was diagnosed in a 22-year-old female Tennessee Walking Horse that had signs of bruxism and ptyalism. Esophageal ulceration was detected via endoscopy. Compared with the damage to the proximal portions of the esophagus, the severity of the ulceration increased toward the gastroesophageal junction. Esophageal ulceration attributable to chronic gastric acid reflux is usually secondary to pyloric outflow obstruction in horses. In the horse of this report, there was no evidence of either a chronic pyloric or duodenal obstruction that could have resulted in esophageal ulceration. Esophageal ulceration in this horse was attributed to gastroesophageal reflux disease, a common condition in humans in which the underlying abnormality is functional incompetence of the gastroesophageal junction. Treatment is directed at decreasing gastric acidity and protecting the ulcerated mucosa. In the horse of this report, treatment was unsuccessful and the horse was euthanatized; a physical cause of gastroesophageal reflux disease was not identified during an extensive postmortem examination.     

Type I immune-mediated polyarthritis in dogs: 39 cases (1997-2002)

OBJECTIVE: To determine clinical signs, laboratory findings, relationship to vaccination, and response to treatment for type I immune-mediated polyarthritis (IMPA) in dogs. DESIGN: Retrospective study. ANIMALS: 39 dogs PROCEDURE: Clinical records and radiographic reports from 3 university referral hospitals were reviewed. Clinical signs, laboratory and investigative findings, relationship to vaccination, and response to treatment were evaluated. RESULTS: Clinical signs and initial laboratory and clinical investigative findings were frequently abnormal but were nonspecific and not associated with likelihood of recovery. Time of vaccination was not associated with onset of disease. Chemotherapeutic immunosuppression resulted in complete cure in 56% of dogs. Continuous medication was required in 18% (7/39) of dogs, relapses were treated successfully in 13% (5/39) of dogs, and 15% (6/39) of dogs died or were euthanatized as a result of disease. CONCLUSIONS AND CLINICAL RELEVANCE: The possible involvement of vaccination in type I IMPA was not made clear from this study because of the small population size. Signalment, clinical signs, and results of diagnostic tests other than multiple synovial fluid analyses were generally nonspecific. Most dogs with type I IMPA responded to initial immunosuppressive treatment, but 31% (12/39) of dogs relapsed, required further treatment, or both.     

Association between cribbing and entrapment of the small intestine in the epiploic foramen in horses: 68 cases (1991-2002)

OBJECTIVE: To determine whether there was an association between a history of cribbing and epiploic foramen entrapment (EFE) of the small intestine in horses. DESIGN: Retrospective study. ANIMALS: 68 horses examined at the University of Illinois or the University of Liverpool veterinary teaching hospitals. PROCEDURE: For horses examined at the University of Illinois that underwent surgery because of strangulating small intestine lesions, information about cribbing was obtained through telephone calls with owners. For horses examined at the University of Liverpool that underwent surgery for colic for any reason, information about cribbing was obtained through a preoperative questionnaire. RESULTS: 13 of 19 (68%) horses with EFE examined at the University of Illinois had a history of cribbing, compared with only 2 of 34 (6%) horses with other strangulating small intestine lesions (odds ratio, 34.7; 95% confidence interval, 6.2 to 194.6). Similarly, 24 of 49 (49%) horses with EFE examined at the University of Liverpool had a history of cribbing, compared with 72 of 687 (10.5%) horses with colic caused by other lesions (odds ratio, 8.2; 95% confidence interval, 4.5 to 15.1). CONCLUSIONS AND CLINICAL RELEVANCE: Results suggest that there may be an association between cribbing and EFE in horses, with horses with a history of cribbing more likely to have EFE than horses without such a history.     

Effects of injection of botulinum toxin type B into the external anal sphincter on anal pressure of horses

OBJECTIVE: To determine effects on anal pressure of horses after local injection of the external anal sphincter with Clostridium botulinum toxin type B. ANIMALS: 11 healthy adult horses. PROCEDURE: Peak and resting anal sphincter pressures were measured with a custom-made rectal probe that was connected to a pressure transducer. Pressures were measured before treatment and after injection with botulinum toxin type B (BTB) or saline (0.9% NaCl) solution. Dose titration with 500, 1,000, 1,500, and 2,500 U of BTB was completed. Physical changes, behavior, and anal pressure were recorded for each horse. RESULTS: Injection of 1,000 U of BTB caused a significant reduction in peak anal pressure from days 2 to 84, compared with pressure in control horses. Maximal effect of the toxin was observed within the first 15 days after injection, followed by a slow return to baseline during the 168-day period. Injection of 2,500 U of BTB in the anal sphincter in 1 horse resulted in lethargy, generalized weakness, and dysphagia for 14 days. Adverse clinical effects were not observed in horses after injections with 500, 1,000, or 1,500 U of BTB. CONCLUSIONS AND CLINICAL RELEVANCE: The effect of focal intramuscular injection of BTB in horses is similar to that reported for other species. However, horses appear to be more sensitive to BTB, compared with other species, and clinical signs of botulism may develop at doses exceeding 1,500 U. Injections of BTB in the external anal sphincter of mares may be useful to reduce incisional dehiscence after repair of perineal lacerations.     

Diversity of Salmonella serovars in feedyard and nonfeedyard playas of the Southern High Plains in the summer and winter

OBJECTIVE: To compare Salmonella isolates cultured from feedyard and nonfeedyard (control) playas (ie, temporary shallow lakes) of the Southern High Plains. SAMPLE POPULATION: Water and muck (sediment) samples were obtained from 7 feedyard playas and 3 nonfeedyard playas in the winter and summer. PROCEDURE: Each water and muck sample was enriched with sulfur-brilliant-green broth and incubated in a shaker at 37 degrees C for 24 hours. A sample (100 mL) of the incubated bacterial-enriched broth was then mixed with 100 mL of fresh sulfur-brilliant-green enrichment broth and incubated in a shaker at 37 degrees C for 24 hours. After the second incubation, a swab sample was streaked on differential media. Suspect Salmonella isolates were further identified by use of biochemical tests, and Salmonella isolates were confirmed and serovar determinations made. RESULTS: Salmonella isolates were not recovered from the 3 control playas. Seven Salmonella enterica serovars were isolated from 5 of 7 feedyard playas in the summer, and 13 S. enterica serovars were isolated from 7 of 7 feedyard playas in the winter. In the summer, 296 isolates were cultured, and 47 were Salmonella organisms. In the winter, 288 isolates were cultured, and 171 were Salmonella organisms. CONCLUSIONS AND CLINICAL RELEVANCE: Results indicated that feedyard playas are frequently contaminated with many Salmonella serovars. These pathogens should be considered whenever feedyard managers contemplate the use of water from these playas. Water from feedyard playas should not be used to cool cattle in the summer or for dust abatement.     

Effect of strain and serotype of vesicular stomatitis virus on viral shedding, vesicular lesion development, and contact transmission in pigs

OBJECTIVE: To determine whether pigs can be infected with strains of vesicular stomatitis virus New Jersey (VSV-NJ) and vesicular stomatitis virus Indiana (VSV-I) isolated during recent vesicular stomatitis outbreaks that primarily involved horses in the western United States and determine the potential for these viruses to be transmitted by contact. ANIMALS: 128 pigs. PROCEDURE: Pigs were challenged with VSV-NJ or VSV-I from the 1995 and 1997 outbreaks of vesicular stomatitis in the western United States, respectively, or with VSV-NJ (OS) associated with vesicular stomatitis in feral pigs on Ossabaw Island, Ga. Pigs (3/group) were inoculated with each virus via 3 routes and evaluated for viral shedding, seroconversion, and the development of vesicular lesions. In another experiment, the potential for contact transmission of each virus from experimentally infected to na?ve pigs was evaluated. RESULTS: Infection of pigs was achieved for all 3 viruses as determined by virus isolation and detection of seroconversion. In inoculated pigs, all 3 viruses were isolated from multiple swab samples at concentrations sufficient to infect other pigs. However, compared with results obtained with the 2 VSV-NJ strains, viral titers associated with VSV-I were low and the duration of virus shedding was reduced. Results from the contact transmission trials were consistent with these results; virus transmission was detected most frequently with the VSV-NJ strains. CONCLUSIONS AND CLINICAL RELEVANCE: Pigs can be infected with VSV-NJ and VSV-I. Differences in the extent of viral shedding and potential for contact transmission were apparent between serotypes but not between the VSV-NJ strains investigated.     

Risk of postnatal exposure to Sarcocystis neurona and Neospora hughesi in horses

OBJECTIVE: To estimate risk of exposure and age at first exposure to Sarcocystis neurona and Neospora hughesi and time to maternal antibody decay in foals. ANIMALS: 484 Thoroughbred and Warmblood foals from 4 farms in California. PROCEDURE: Serum was collected before and after colostrum ingestion and at 3-month intervals thereafter. Samples were tested by use of the indirect fluorescent antibody test; cutoff titers were > or = 40 and > or = 160 for S neurona and N hughesi, respectively. RESULTS: Risk of exposure to S neurona and N hughesi during the study were 8.2% and 3.1%, respectively. Annual rate of exposure was 3.1% for S neurona and 1.7% for N hughesi. There was a significant difference in the risk of exposure to S neurona among farms but not in the risk of exposure to N hughesi. Median age at first exposure was 1.2 years for S neurona and 0.8 years for N hughesi. Highest prevalence of antibodies against S neurona and N hughesi was 6% and 2.1 %, respectively, at a mean age of 1.7 and 1.4 years, respectively. Median time to maternal antibody decay was 96 days for S neurona and 91 days for N hughesi. There were no clinical cases of equine protozoal myeloenchaphlitis (EPM). CONCLUSIONS AND CLINICAL RELEVANCE: Exposure to S neurona and N hughesi was low in foals between birth and 2.5 years of age. Maternally acquired antibodies may cause false-positive results for 3 or 4 months after birth, and EPM was a rare clinical disease in horses < or = 2.5 years of age.