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Abstract

Objective—To test the hypothesis that strangulation of the small intestine by a lipoma or in the epiploic foramen is more common in older horses.

Design—Retrospective study.

Animals—46 horses.

Procedure—Ages of horses with strangulation of the small intestine by a lipoma (n = 29) or in the epiploic foramen (17) were compared with ages of 79 horses with miscellaneous small intestinal lesions. Effects of increasing age on risk of the diseases of interest were examined by use of logistic regression and a 1-sided trend test for binomial proportions.

Results—Mean age of the horses with strangulation in the epiploic foramen (9.6 years) was the same as that for the horses with miscellaneous small intestinal lesions (7.7), but mean age of the horses with strangulation by a lipoma (19.2) was significantly greater than that for the other groups. The proportion of horses with lipoma increased significantly with increasing age, but the proportion with strangulation in the epiploic foramen did not.

Conclusions and Clinical Relevance—Results refute the current suggestion that increasing age predisposes horses for strangulation of the small intestine in the epiploic foramen but support the suggestion that the risk of strangulation of the small intestine by a lipoma increases with age. (J Am Vet Med Assoc 2001;219:87–89)

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in Journal of the American Veterinary Medical Association

Abstract

Objective—To evaluate survival rate and complications after jejunocecostomy in horses with colic and to compare outcomes after hand-sewn versus stapled side-to-side jejunocecostomy.

Design—Retrospective cohort study. Animals—32 horses.

Procedures—Information was retrieved from medical records and through telephone calls on horses that had a hand-sewn or stapled side-to-side jejunocecostomy for treatment of colic, which was performed by or under the supervision of the same surgeon. KaplanMeier life table analysis was used to compare survival times and rates between horses that underwent a hand-sewn or stapled side-to-side anastomosis.

Results—32 horses met inclusion criteria; 22 underwent a hand-sewn anastomosis, and 10 underwent a stapled anastomosis. Horses in the stapled group had a significantly greater prevalence of postoperative colic and combined postoperative colic and reflux than horses in the hand-sewn group. In the hand-sewn group, repeated celiotomy was performed within the same hospitalization period for 3 of 22 horses; in the stapled group, 4 of 10 horses had repeated celiotomies. Hospital discharge rates (ie, short-term survival rates) were similar between horses in the hand-sewn group (20/22 horses) and those in the stapled group (9/10 horses). Long-term survival rates were similar for both groups, ranging from 5 to 126 months. Conclusions and Clinical Relevance—Short- and long-term results justify use of jejunocecostomy in horses. Despite similar survival rates between groups, horses that underwent a stapled anastomosis had significantly greater prevalences of postoperative complications than horses that underwent a hand-sewn anastomosis, suggesting that horses were sensitive to minor differences in anastomosis techniques.

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in Journal of the American Veterinary Medical Association

Abstract

Objective—To determine the rate of development of septic arthritis after elective arthroscopy and evaluate associations between various factors and development of this complication in horses.

Design—Retrospective case series.

Animals—682 horses that underwent arthroscopic procedures at the University of Illinois Veterinary Teaching Hospital from 1994 to 2003.

Procedures—Information pertaining to signalment, joints treated, whether antimicrobials were administered, and development of postoperative septic arthritis was collected from medical records. Horses with a primary problem of septic arthritis or wounds involving joints were excluded. The following factors were evaluated to determine their roles in joint sepsis: breed, sex, joint, and preoperative and intra-articular administration of antimicrobials. Telephone interviews with clients were used to determine whether unreported septic arthritis had developed.

Results—8 of 932 (0.9%) joints in 7 of 682 (1.0%) horses that underwent arthroscopy developed postoperative septic arthritis. Follow-up information after discharge from the hospital was available for 461 of the 682 horses, and of those, 8 of 627 (1.3%) joints in 7 of 461 (1.5%) horses developed septic arthritis. Breed and joint treated were significant risk factors for development of postoperative septic arthritis, with draft breeds and tibiotarsal joints more likely than others to be affected. Sex, preoperatively administered antimicrobials, and intra-articularly administered antimicrobials were not associated with development of postoperative septic arthritis.

Conclusions and Clinical Relevance—Results can be used for comparison with data from other institutions and surgical facilities. Additional precautions should be undertaken when arthroscopic surgery involves draft breeds and tibiotarsal joints.

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in Journal of the American Veterinary Medical Association

Abstract

Objective—To determine effects of reactive oxygen metabolites (ROMs), with and without flunixin meglumine, on equine right ventral colon (RVC) in vitro.

Animals—18 healthy horses and ponies.

Procedures—In 3 groups of 6 animals each, short-circuit current and conductance were measured in RVC mucosa in Ussing chambers. The 3 groups received physiologic saline (0.9% NaCl) solution, IV, 10 minutes before euthanasia and tissue incubation in Krebs-Ringer-bicarbonate (KRB) solution; flunixin meglumine (1.1 mg/kg, IV) 10 minutes before euthanasia and tissue incubation in KRB solution; or physiologic saline solution, IV, 10 minutes before euthanasia and incubation in KRB solution with 2.7 × 10−5M flunixin meglumine. Incubation conditions included control (no addition) and ROM systems, including addition of 1mM xanthine and 80 mU of xanthine oxidase (to produce the superoxide radical), 1mM H2O2, and 1mM H2O2 and 0.5mM ferrous sulfate (to produce the hydroxyl radical).

Results—All ROMs that were added or generated significantly increased the short-circuit current except in tissues coincubated with flunixin meglumine, and they induced mild epithelial vacuolation and apoptosis, but did not disrupt the epithelium nor change conductance, lactate dehydrogenase release, or [3H]mannitol flux.

Conclusions and Clinical Relevance—Responses to ROMs could be attributed to increased chloride secretion and inhibited neutral NaCl absorption in equine RVC, possibly by stimulating prostaglandin production. The ROMs examined under conditions of this study could play a role in prostaglandin-mediated colonic secretion in horses with enterocolitis without causing direct mucosal injury.

Full access
in American Journal of Veterinary Research

Abstract

OBJECTIVE

To examine bicarbonate (HCO3 ) secretion ex vivo in the equine large colon to determine any differences between the right dorsal colon (RDC) and right ventral colon (RVC). The effect of phenylbutazone (PBZ) on HCO3 secretion was examined in the RDC.

ANIMALS

14 healthy horses.

PROCEDURES

In anesthetized horses (n = 10), segments of mucosa from RDC and RVC were harvested to measure HCO3 secretion ex vivo with the pH Stat method. The effect of PBZ on HCO3 secretion in the RDC was studied in 4 additional horses.

RESULTS

Three distinct mechanisms of HCO3 secretion previously described in a murine model were confirmed in the equine colon. The RDC had a greater capacity for electrogenic, Cl-independent HCO3 secretion than the RVC (P = 0.04). In the RDC, all HCO3 secretion was decreased by PBZ (P < 0.02) but was not studied in the RVC because of low baseline secretion.

CLINICAL RELEVANCE

Secretion of HCO3 by the RDC could play a pivotal role in equine colon physiology, because intense microbial fermentation in this site could require HCO3 secretion to buffer short-chain fatty acids. Inhibition of this secretion by PBZ could interfere with mucosal buffering and predispose to changes associated with right dorsal colitis.

Open access
in American Journal of Veterinary Research

Abstract

Case Description—A 6-year-old Appaloosa mare was examined because of inappetance, difficulty eating, and swelling and mucopurulent discharge in the right eye.

Clinical Findings—Results of a CBC and serum bio-chemical analysis revealed no important findings. Ophthalmologic examination revealed scarring and ulcer-ation of the superficial layers of the cornea. Endoscopic examination of the upper portion of the respiratory tract and auditory tube diverticula (guttural pouches) revealed abnormal thickness of the right stylohyoid bone and a plaque suggestive of mycotic growth on the left internal carotid artery. Radiographic examination revealed right-sided otitis media. Temporohyoid osteoarthropathy in the right guttural pouch and mycosis in the left guttural pouch were diagnosed.

Treatment and Outcome—Ceratohyoidectomy of the right stylohyoid bone was performed, and the left internal carotid artery was occluded via placement of stainless steel spring embolization coils. The mare regained the ability to eat without difficulty and improved clinically for approximately 4 weeks. However, the mare returned to the medical center 53 days after surgery with left-sided Horner syndrome, atrophy of the right side of the tongue, and a 3-week history of dysphagia and weight loss. Endoscopic evaluation revealed progression of mycotic growth in the left guttural pouch. The mare was euthanatized.

Clinical Relevance—Although the mycotic lesion in the left guttural pouch was an incidental finding at the time of initial examination, the lesion progressed to cause dysphagia and Horner syndrome after occlusion of the left internal carotid artery, a treatment that is typically associated with resolution of guttural pouch mycosis. Arterial occlusion is not necessarily a reliable method of resolving guttural pouch mycosis.

Restricted access
in Journal of the American Veterinary Medical Association

Abstract

Objectives—To evaluate the in vitro protective effects of acetylcysteine and response of resident mucosal eosinophils in oxidant-induced injury to tissues of right dorsal colon of horses.

Animals—9 adult horses.

Procedure—Gastrointestinal mucosa was damaged in vitro with 3mM hypochlorous acid (HOCl), with and without prior exposure to 6mM acetylcysteine. Control tissues were not exposed to HOCl or acetylcysteine. Control and damaged tissues were incubated in Krebs-Ringer-bicarbonate solution and tissue resistance measured during 240 minutes. Tissue permeability to radiolabeled mannitol was also used to assess mucosal barrier integrity. Tissues were examined by light microscopy before and after HOCl exposure and during and after incubation.

Results—Exposure to HOCl caused tissue damage and decreased tissue resistance. Restitution did occur during the incubation period. Eosinophils were located near the muscularis mucosae in freshly harvested tissues and migrated towards the luminal surface in response to HOCl-induced injury. Compared with tissues treated with HOCl without acetylcysteine, pretreatment with acetylcysteine prevented HOCl-induced tissue damage, changes in resistance, and histologically detectable eosinophil migration. The permeability to mannitol increased to the same extent in tissues treated with HOCl alone or with acetylcysteine and HOCl.

Conclusions and Clinical Relevance—Eosinophils migrated toward the mucosal surface in equine colon in response to oxidant-induced damage in vitro. This novel finding could be relevant to inflammation in equine colon and a pathophysiologic feature of many colonic diseases. Acetylcysteine protected the mucosa against oxidant-induced injury and may be useful as a treatment option for various gastrointestinal tract disorders in horses. (Am J Vet Res 2003;64:1205–1212)

Full access
in American Journal of Veterinary Research

Abstract

Objective—To study the effects of phenylbutazone, indomethacin, prostaglandin E2 (PGE2), glutamine, and butyrate on restitution of oxidant-injured right dorsal colon of horses in vitro.

Sample Population—Right dorsal colon from 9 adult horses euthanatized for reasons other than gastrointestinal tract disease.

Procedure—Mucosal segments from the right dorsal colon were injured via exposure to HOCl and incubated in Ussing chambers in solutions containing phenylbutazone, indomethacin, indomethacin and PGE2, glutamine, and butyrate. Transepithelial resistance and mucosal permeability to mannitol were measured, and all mucosal segments were examined histologically.

Results—The HOCl-injured mucosa had lower resistance and higher permeability to mannitol, compared with control tissue. Histologic changes were also evident. Resistance of HOCl-injured mucosa recovered partially during the incubation period, and glutamine improved recovery. Phenylbutazone and indomethacin increased resistance, but these increases were not significant. Butyrate and PGE2 had no effects, compared with nontreated HOCl-injured tissues. Mucosal permeability to mannitol was lower in glutamine-treated tissue, compared with nontreated tissue. Histologic changes reflected the resistance and permeability changes.

Conclusions and Clinical Relevance—According to our findings, phenylbutazone and indomethacin do not seem to interfere with restitution of oxidant-injured mucosa of equine colon in vitro, and glutamine could facilitate mucosal restitution. (Am J Vet Res 2004;65:1589–1595)

Full access
in American Journal of Veterinary Research

Abstract

Objectives—To study the functional and structural responses of the right dorsal colon (RDC) of ponies to phenylbutazone (PBZ) in vitro at a concentration that could be achieved in vivo.

Animals—8 adult ponies.

Procedure—Short circuit current and conductance were measured in mucosa from the RDC. Tissues incubated with and without HCO3 were exposed to PBZ, bumetanide, or indomethacin. Bidirectional Cl fluxes were determined. After a baseline flux period, prostaglandin E2 (PGE2) was added to the serosal surfaces and a second flux period followed. Light and transmission electron microscopy were performed.

Results—Baseline short circuit current was diminished significantly by PBZ and indomethacin, and increased significantly after addictions of PGE2. After PGE2 was added, Cl secretion increased significantly in tissues in HCO3--free solutions and solutions with anti-inflammatory drugs, compared with corresponding baseline measurements and with control tissues exposed to PGE2. Bumetanide did not affect baseline short circuit current and Cl fluxes. The predominant histologic change was apoptosis of surface epithelial cells treated with PBZ and to a lesser extent in those treated with indomethacin.

Conclusions and Clinical Relevance—Prostaglandin- induced Cl secretion appeared to involve a transporter that might also secrete HCO3 . Both PBZ and indomethacin altered ion transport in RDC and caused apoptosis; PBZ can damage mucosa through a mechanism that could be important in vivo. The clinically harmful effect of PBZ on equine RDC in vivo could be mediated through its effects on Cl and HCO3 secretion. (Am J Vet Res 2002;220:934–941)

Full access
in American Journal of Veterinary Research

Abstract

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. ( J Am Vet Med Assoc 2004;224:562–564)

Restricted access
in Journal of the American Veterinary Medical Association