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Abstract

Objective

To determine whether xanthine oxidase and dehydrogenase activities are altered during low flow ischemia and reperfusion of the small intestine of horses.

Animals

5 clinically normal horses without histories of abdominal problems.

Procedure

With the horse under general anesthesia, a laparotomy was performed and blood flow to a segment of the distal jejunum was reduced to 20% of baseline for 120 minutes and was then reperfused for 120 minutes. Biopsy specimens were obtained before, during, and after ischemia for determination of xanthine oxidase and dehydrogenase activities, and for histologic and morphometric analyses.

Results

Percentage of xanthine oxidase activity (as a percentage of xanthine oxidase and dehydrogenase activity) was not altered during ischemia and reperfusion. An inflammatory response developed and progressed during ischemia and reperfusion. Mucosal lesions increased in severity after ischemia and reperfusion. Mucosal surface area and volume decreased during ischemia and continued to decrease during reperfusion. Submucosal volume increased slightly during ischemia, and continued to increase during reperfusion.

Conclusions and Clinical Relevance

Evidence for conversion of xanthine dehydrogenase to xanthine oxidase during ischemia was not found. Factors other than production of reactive oxygen metabolites may be responsible for progressive epithelial loss, decrease in mucosal surface area and volume, and increase in submucosal volume observed in this study. Other methods of determining xanthine oxidase activity that detect the enzyme in sloughed epithelial cells should be used to better define the importance of this pathway in jejunal reperfusion injury in horses. (Am J Vet Res 1998;59:772-776)

Free access
in American Journal of Veterinary Research

Abstract

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 (R 2 = 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.

Free access
in American Journal of Veterinary Research

SUMMARY

Neutrophils were isolated from the blood of pregnant cows on days 255, 265, and 275 of pregnancy, and on the day of parturition (n = 5/group), and in addition, simultaneously from 4 ovariectomized healthy cows (control animals). Neutrophils were subjected to neutrophil function assays (chemotaxis against zymosan-activated serum, random migration, ingestion of 125I-iododeoxyuridine [IdUR]-labeled Staphylococcus aureus, iodination of proteins, cytochrome C reduction, antibody-independent and antibody-dependent cell-mediated cytotoxicity). Results were expressed as percentage of control animals. Fetal placental tissue (cotyledon), uterine wall tissue, and skeletal muscle were obtained from the principal animals on the aforementioned days via laparotomy, and tissue suspensions were prepared. Chemotaxis of neutrophils was tested against tissue supernatants. Compared with day 255, there was an increase in ingestion of 125I-IdUR-S aureus at parturition, whereas iodination of proteins and cytochrome C reduction were reduced on the day of calving. The other neutrophil functions tested did not change over time of gestation. Fetal placental and uterine wall tissue attracted neutrophils with uterine wall tissue having a tendency to be more potent than cotyledonary tissue. Skeletal muscle tissue did not attract neutrophils. There was no change in chemotaxis response of neutrophils evoked by intrauterine and uterine tissues over time of gestation. It was concluded that at parturition, neutrophil function is impaired with respect to their bactericidal effects, which may render the animal more susceptible to bacterial infections, and that the chemoattractant properties of fetal placental and uterine wall tissues are tissue-specific, at least when compared with skeletal muscle. The presence of neutrophils in the placenta and other parts of the uterus may be necessary for placental separation and prevention from postpartum intrauterine bacterial infections, respectively.

Free access
in American Journal of Veterinary Research

to maintain consistent analysis. For the buccal site, video recordings were obtained from the mucogingival junction dorsal to a carnassial tooth. For the intestinal site in the loop of jejunum that was exteriorized and packed off with laparotomy

Full access
in American Journal of Veterinary Research

], ovariohysterectomy and bilateral mastectomy or electromagnetic treatment of a soft tissue mass [2], cystotomy [2], and laparotomy [1]) or extraperitoneal procedures (orthopedic surgery [4], castration and removal of a soft tissue mass [1], removal of a soft tissue

Full access
in American Journal of Veterinary Research

. Use of cisplatin, 5-fluorouracil, and second-look laparotomy for the management of gastrointestinal adenocarcinoma in three dogs . J Am Vet Med Assoc 2004 ; 225 : 1412 – 1417 . 10.2460/javma.2004.225.1412 3. Chang SC , Liao JW

Full access
in American Journal of Veterinary Research

mucosal tissue layer. Materials and Methods Sample Intestinal mucosal samples were collected from adult horses of both sexes and various breeds and body sizes that were admitted with signs of colic and underwent exploratory laparotomy at the

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in American Journal of Veterinary Research

of clinicopathologic evidence of hepatic disease, whereas 3 were collected because of gross hepatic abnormalities observed during exploratory laparotomy in patients with health concerns unrelated to hepatic disease. Hepatobiliary diagnosis

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in American Journal of Veterinary Research

to monitor heart rate. Midline laparotomy and bilateral ligation of the renal artery and vein were performed in all rats, and the abdominal cavity was closed in a routine manner. Rats were assigned into 2 groups; there were 6 rats in the control

Full access
in American Journal of Veterinary Research