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- Author or Editor: Anthony T. Blikslager x
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Abstract
Objective—To examine whether a zinc l -carnosine compound used for treatment of suspected gastric ulcers in dogs ameliorates acid-induced injury in canine gastric mucosa.
Sample—Gastric mucosa from 6 healthy dogs.
Procedures—Mucosa from the gastric antrum was harvested from 6 unadoptable shelter dogs immediately after euthanasia and mounted on Ussing chambers. The tissues were equilibrated for 30 minutes in neutral Ringer's solution prior to incubation with acidic Ringer's solution (HCl plus Ringer's solution [final pH, 1.5 to 2.5]), acidic Ringer's solution plus zinc l -carnosine compound, or zinc l -carnosine compound alone. Tissues were maintained for 180 minutes in Ussing chambers, during which permeability was assessed by measurement of transepithelial electrical resistance. After the 180-minute treatment period, tissues were removed from Ussing chambers and labeled with immunofluorescent anti–active caspase-3 antibody as an indicator of apoptosis.
Results—Permeability of the gastric mucosa was significantly increased in a time-dependent manner by addition of HCl, whereas control tissues maintained viability for the study period. Change in permeability was detected within the first 15 minutes after acid application and progressed over the subsequent 150 minutes. The zinc l -carnosine compound had no significant effect on this increase in permeability. Apoptosis was evident in acid-treated tissues but not in control tissues. The zinc l -carnosine compound did not protect against development of apoptosis.
Conclusions and Clinical Relevance—Addition of HCl caused a dose-dependent increase in gastric permeability over time and apparent induction of apoptosis as determined on the basis of immunofluorescence. However, there was no significant protective effect of a zinc l-carnosine compound. Nonetheless, results suggested the utility of this method for further studies of canine gastric injury.
Abstract
Objective—To determine whether ischemia and flunixin affect in vitro lipopolysaccharide (LPS) absorption in samples of the jejunum of horses.
Animals—12 horses.
Procedure—Horses were anesthetized, a midline celiotomy was performed, and the jejunum was located. Two 30-cm sections of jejunum (60 cm apart) were selected. One segment was designated as control tissue; ischemia was induced in the other segment for 120 minutes. Horses were then euthanatized. Mucosa from each jejunal segment was mounted on Ussing chambers and treated with or without flunixin. Tissues from 6 horses were used to assess permeability to radiolabeled LPS; mucosal samples from the remaining 6 horses were incubated with fluorescent-labeled LPS (FITC-LPS) and examined histologically. Production of tumor necrosis factor-α (TNF-α) and production of LPS-binding protein (LBP) were assessed as indicators of mucosal response to LPS.
Results—Ischemia significantly increased mucosal permeability to LPS, but by 180 minutes, the mucosa was not more permeable than control tissue. Flunixin treatment adversely affected intestinal barrier function throughout the experiment but did not result in increased mucosal permeability to LPS. Compared with control tissues, LBP production was increased by ischemia and reduced by exposure to LPS. In ischemic tissue, FITC-LPS entered the lamina propria but TNF-α was produced on the mucosal side only, indicating little response to the absorbed LPS.
Conclusions and Clinical Relevance—Ischemia increased LPS passage across equine jejunal mucosa. Flunixin delayed mucosal recovery but did not exacerbate LPS absorption. Evaluation of the clinical importance of flunixin-associated delayed mucosal recovery requires further in vivo investigation. (Am J Vet Res 2004;65:1377–1383)
Objective—
To assess the ability of clinicians to predict the site and type of lesion as well as outcome in horses with colic.
Design—
Prospective case study.
Sample population—
139 horses admitted for evaluation of signs of colic.
Procedure—
Six interns and residents examined horses with colic and predicted the segment of intestine that was affected, the type of lesion, and whether the horse would survive to discharge. Accuracy of prediction of site and type of lesion and survival prediction was compared between the first and second halves of the year, using X2 analysis and 95% confidence intervals on sensitivity and specificity. X2 Analysis was used to assess accuracy between predicted site and type of lesion and intraoperative or necropsy findings and to assess accuracy between predicted survival and actual outcome.
Results—
Significant association existed between predicted segment of affected intestine or type of lesion and intraoperative findings (P < 0.05). There was a significant association between predicted survival and outcome (P < 0.001). Accuracy of survival prediction improved significantly (P = 0.002) during the year.
Clinical Implications—
Clinicians can accurately predict horses with colic that will survive surgery on the basis of clinical impressions. The ability to predict those horses that will survive improves with training.
Abstract
Objective—To assess expression of cyclooxygenase (COX)-1 and -2 in naturally occurring squamous cell carcinomas (SCCs) and the analogous normal tissues in horses.
Sample Population—Tissue samples collected from 3 conjunctival, 2 vulvar, 4 preputial, and 5 penile SCCs during surgical excision in 14 horses and from corresponding body regions (conjunctiva [n = 5 horses], vulva [2], prepuce [3], and penis [3]) in 5 horses euthanized for reasons unrelated to neoplasia.
Procedures—Tissue samples were snap frozen in liquid nitrogen and stored at −80°C until analysis. Protein was extracted from the frozen tissues, and western blot analyses were performed. Nonneoplastic and abnormal tissues from each body region were run on the same blot, and blots were run in triplicate. Molecular-weight markers and COX-1 and 2 ovine standards (positive control samples) were run concurrently on the gels; negative control samples were not used.
Results—All tissues, including the nonneoplastic and SCC tissues, expressed both COX-1 and -2 proteins.
Conclusions and Clinical Relevance—Results indicated that the expression of COX proteins in both nonneoplastic and SCC-affected tissues in horses is markedly different from that in other species. The reason for the potential benefit of COX-2 inhibitors in horses and other species is unknown. Further research needs to be performed to evaluate the efficacy of COX-2 inhibitors as cancer treatments in horses. Investigation of the mechanisms of tumor development in horses should be performed to increase understanding of this disease and ascertain how the mechanisms differ from those in other animals.
