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  • Author or Editor: Anthony Blikslager x
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Abstract

Objective—To develop an endoscopic technique for use in monitoring devlopment of gastric ulcers via a gastric cannula during withholding of feed and administration of a finely ground diet to pigs.

Animals—6 pigs weighing between 60 and 70 kg.

Procedure—A gastric cannula was surgically inserted adjacent to the pars esophagea in each pig. Pigs were fed a finely ground diet for two 7-day periods that were separated by a 48-hour period during which feed was withheld. Endoscopic examination via the gastric cannula was used to monitor development of ulcers in the pars esophageal region of the pigs during the 48-hour period of feed withhold and subsequent 7-day feeding period. An ulcer score was assigned during each endoscopic examination. A final examination was performed during necropsy and compared with results for the final endoscopic examination.

Results—Consumption of a finely ground diet for 7 days resulted in progressive erosive damage to the pars esophageal region of the stomach. Further significant increases in ulcerative damage were detected after 24 and 48 hours of withholding of feed. Final examination during necropsy did not reveal significant differences from results obtained during the final endoscopic examination.

Conclusions and Clinical Relevance—Endoscopic examination via a gastric cannula was an effective means of monitoring ulcer development in the pars esophagea of pigs. Feeding a finely ground diet and withholding of feed induced endoscopically observable ulcers in the stratified squamous epithelial region of the stomach. Direct visual examination during necropsy confirmed the accuracy of endoscopic examination. (Am J Vet Res 2002;63:1076–1082)

Full access
in American Journal of Veterinary Research

Abstract

Objective—To identify expression and localization of cyclooxygenase (COX)-1 and COX-2 in healthy and ischemic-injured left dorsal colon of horses.

Sample Population—Left dorsal colon tissue samples from 40 horses.

Procedures—Tissue samples that were used in several related studies on ischemia and reperfusion were evaluated. Samples were collected during anesthesia, before induction of ischemia, and following 1 hour of ischemia, 1 hour of ischemia and 30 minutes of reperfusion, 2 hours of ischemia, 2 hours of ischemia and 30 minutes of reperfusion, and 2 hours of ischemia and 18 hours of reperfusion. Histomorphometric analyses were performed to characterize morphological injury. Immunohistochemical analyses were performed to characterize expression and localization of COX-1 and COX-2.

Results—COX-1 and COX-2 were expressed in control tissues before ischemia was induced, predominantly in cells in the lamina propria. Ischemic injury significantly increased expression of COX-2 in epithelial cells on the colonic surface and in crypts. A similar significant increase of COX-1 expression was seen in the epithelial cells.

Conclusions and Clinical Relevance—On the basis of information on the role of COX-2, upregulation of COX-2 in surface epithelium and crypt cells following ischemic injury in equine colon may represent an early step in the repair process.

Full access
in American Journal of Veterinary Research

Abstract

Objective—To determine whether clinically normal dogs have lesions in the pylorus and duodenum and to examine the expression of cyclooxygenase (COX) isoforms in the pylorus and duodenum of these dogs.

Animals—27 clinically normal dogs.

Procedures—Physical examination was performed on clinically normal dogs from animal shelters and research projects; the dogs were then euthanized. After the dogs were euthanized, the pylorus and duodenum were photographed and scored for gross appearance of lesions. Samples were obtained for histologic evaluation and determination of COX expression via western blot analyses. Tissues from the pylorus and duodenum were categorized as normal, inflamed, or eroded on the basis of histologic analysis. Each histologic category of tissue was then evaluated to determine the correlation with gross appearance and COX expression.

Results—Of the 27 dogs, 5 had unremarkable histologic findings in the pylorus and duodenum. Inflammation was found in the pylorus of 10 dogs and in the duodenum of 5 dogs. Epithelial erosion was detected in the pylorus of 1 dog and in the duodenum of 3 dogs. Gross appearance was not significantly correlated with histologic appearance. Expression of COX-1 was not upregulated by inflammation, whereas COX-2 expression was increased by inflammation or erosion.

Conclusions and Clinical Relevance—Dogs that appear to be clinically normal may have underlying gastroduodenal lesions associated with upregulation of COX-2. Because of the inability to determine this during routine physical examination, practitioners should be aware of this potential situation when prescribing COX inhibitors.

Full access
in American Journal of Veterinary Research

Abstract

Objective—To assess in vivo effects of short-term administration of NSAIDs with varied cyclooxygenase (COX)-2 selectivity on pyloric and duodenal mucosa.

Animals—8 healthy dogs.

Procedures—Each dog received deracoxib (2 mg/kg, PO, q 24 h for 3 days), firocoxib (5 mg/kg, PO, q 24 h for 3 days), meloxicam (0.2 mg/kg, PO, q 24 h for 1 day followed by 0.1 mg/kg, PO, q 24 h for 2 days), or placebo orally for 3 days; there was a 4-week interval between successive treatments. Prior to and on day 3 of drug administration, pyloric and duodenal mucosae were assessed endoscopically and biopsy specimens obtained for histologic examination. Cyclooxygenase-1 and -2 protein expressions were assessed (western blotting) and prostanoid concentrations measured (ELISAs). Data were analyzed by use of an ANOVA.

Results—Drug administration did not significantly affect endoscopic mucosal scores, histologic scores, or COX-1 or -2 protein expression. The COX-1 protein expression was significantly higher in the pylorus than in the duodenum. Total prostaglandin and thromboxane B2 (TXB2) concentrations were significantly greater in pyloric than in duodenal mucosa. Drug administration had no effect on prostaglandin or TXB2 concentrations.

Conclusions and Clinical Relevance—Prostanoid concentrations in gastric and duodenal tissues, and gross and histologic appearances, were not significantly affected by drugs with varied COX-2 selectivity. These findings suggested that, for these experimental conditions, there were no differences among the preferential and selective COX-2 inhibitors with regard to adverse effects on the gastric and duodenal portions of the gastrointestinal tract of dogs.

Full access
in American Journal of Veterinary Research

Abstract

Objective—To identify factors associated with gastrointestinal tract perforation in dogs being treated with a selective cyclooxygenase-2 (COX-2) inhibitor (deracoxib).

Design—Retrospective study.

Animals—29 dogs.

Procedure—The Novartis Animal Health pharmacovigilance database was searched for records of dogs treated with deracoxib in which gastrointestinal tract perforation was documented.

Results—16 of the 29 (55%) dogs had received deracoxib at a dosage higher than that approved by the FDA for the particular indication being treated, with 25 (86%) dogs having received deracoxib at a dosage > 2 mg/kg/d (0.9 mg/lb/d). Seventeen (59%) dogs had received at least 1 other nonsteroidal anti-inflammatory drug (NSAID) or a corticosteroid in close temporal association (within 24 hours) with deracoxib administration (ie, immediately before or following). In all, 26 (90%) dogs had received deracoxib at a higher-than-approved dosage or had received at least 1 other NSAID or corticosteroid in close temporal association with deracoxib administration. Twenty dogs died or were euthanatized, and 9 survived.

Conclusions and Clinical Relevance—In dogs with gastrointestinal tract perforation and that had been treated with deracoxib, perforation was most likely attributable to a number of factors. Deracoxib should only be used at approved dosages. Cortico-steroids and other less selective NSAIDs should not be administered in close temporal association with selective COX-2 inhibitors, including deracoxib. Further study is required to define this problem. (J Am Vet Med Assoc 2005;227:1112–1117)

Full access
in Journal of the American Veterinary Medical Association

Summary

Holding power was determined for various orthopedic screws in bones of calves. Holding power was defined as maximal tensile force required to remove a screw divided by thickness of bone engaged by the screw (kKN/mm). Comparative pull-out tests were performed, using pairs of large metacarpal or metatarsal bones from calves aged 3 to 14 days. Comparisons were made of the holding power of 6.5-mm fully threaded cancellous screws and 5.5-mm cortical screws in the proximal and distal metaphyses, and of 4.5-mm and 5.5-mm cortical screws in the diaphysis. Sixteen repetitions of each comparative trial were performed.

There was no statistically significant difference in the holding power of 4.5- and 5.5-mm cortical screws in the diaphysis. There was no significant difference in the holding power of 5.5-mm cortical and 6.5-mm fully threaded cancellous screws in the proximal metaphysis. In the distal metaphysis, 6.5-mm fully threaded cancellous screws had significantly (P < 0.001) greater holding power than did 5.5-mm cortical screws. There was no significant difference between the mean holding power of 5.5-mm cortical screws in the proximal metaphysis and 5.5-mm cortical screws in the distal metaphysis. There was significantly (P < 0.01) greater mean holding power of 6.5-mm cortical, fully threaded cancellous screws in the distal metaphysis, compared with the proximal metaphysis.

Free access
in American Journal of Veterinary Research

Summary

The medical records of 17 horses that were evaluated and treated because of colic caused by pedunculated lipomas between 1983 and 1990 were reviewed. The mean age of the horses was 16.6 ± 3.9 years (range, 10 to 26 years), which was significantly greater than that of the population of horses evaluated because of colic (control population) during the same period. There were significantly more geldings (76.5%), compared with the control population.

Nasogastric reflux ranged from 1 to 16 L in 8 horses and was not obtained in 9 horses. Abdominal palpation per rectum revealed small intestinal distention in 13 horses, displaced large colon in 7 horses, and large colon impaction in 2 horses. Peritoneal fluid was abnormal in 11 of 12 horses from which it was obtained successfully.

One horse was euthanatized after unsuccessful medical treatment. Surgery was performed in 16 horses. Lipomas were blindly resected in 5 horses or exteriorized and resected in 6 horses. The method used to resect the lipoma was not recorded in 5 horses. The ileum and/or jejunum was strangulated in 15 horses, the small colon was strangulated in 1 horse, and the jejunum was obstructed in 1 horse. The length of intestine resected ranged from 0.15 to 7.2 m.

Fourteen horses survived surgery, of which 11 were discharged from the hospital (short-term survival rate of 78.6%). Excluding 2 horses lost to follow-up evaluation, 6 of 12 horses that survived surgery were alive 2 to 56 months following surgery (long-term survival rate of 50%), and 9 of 15 horses died or were euthanatized (fatality rate of 60%).

Free access
in Journal of the American Veterinary Medical Association

Objective

To determine whether complete cecal bypass, by jejunocolostomy or ileocolostomy, is an effective treatment for horses with cecal impaction.

Design

Retrospective analysis of medical records.

Animals

9 horses with cecal impaction managed by jejunocolostomy (3) or ileocolostomy (6) performed with or without typhlotomy for evacuation of cecal contents.

Procedure

Information on age, breed, gender, duration of medical treatment, preoperative abnormalities, surgical procedure, and postoperative complications was retrieved from the medical records. Follow-up data were obtained via telephone interview with owners.

Results

6 males and 3 females between 9 and 24 years old (median, 14 years) were included. Five of 9 horses had signs of mild pain associated with reintroduction of food after surgery. All 7 horses for which follow-up information was available were still alive between 7 and 54 months (median, 1.5 years) after surgery.

Clinical Implications

Jejunocolostomy or ileocolostomy resulted in apparently permanent resolution of cecal impaction in these horses and acceptable long-term outcomes. Mild signs of abdominal pain associated with the onset of feeding can be expected in the early postoperative period. (J Am Vet Med Assoc 1996;209:1287–1290)

Free access
in Journal of the American Veterinary Medical Association