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  • Author or Editor: Anthony T. Blikslager x
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Enteric disease continues to be a substantial problem in the swine industry, contributing to poor growth performance, increased morbidity and mortality rates, compromised welfare, and economic losses. Advances in the understanding of swine management, vaccine technology, and prophylactic antimicrobial regimens have substantially reduced the impact of certain diarrheal diseases of swine, but several pathogens continue to pose major challenges to the swine industry. Intensive management practices and changes in genetics have likely led to increased susceptibility of pigs to common enteric pathogens and the emergence of new pathogens that were once considered commensal. Several of these pathogens have not been

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in Journal of the American Veterinary Medical Association

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)

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in American Journal of Veterinary Research

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.

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in American Journal of Veterinary Research
in Journal of the American Veterinary Medical Association

Abstract

Objective—To determine demographic characteristics of horses donated to the North Carolina State University Equine Health Center (EHC) between 1996 and 2008.

Design—Retrospective cohort study.

Animals—122 horses donated to the EHC between January 1996 and December 2008, and 246 horses offered for donation to the EHC between January 2007 and December 2008.

Procedures—Telephone and medical records were examined. Data were collected in 5 categories: age, sex, breed, reason for donation, and use prior to donation.

Results—From January 1996 through December 2008, 122 horses were donated to the EHC (median, 3 horses/y; range, 0 to 39 horses/y). There were 131 and 115 horses offered for donation during 2007 and 2008, respectively, of which 38 and 23 were accepted. Mean ± SD age of horses offered for donation during 2007 and 2008 was 12.7 ± 6.7 years, with 75 of the 246 (30.5%) horses between 6 and 10 years old. Musculoskeletal disease was the most commonly listed reason horses were offered for donation (115/240 [47.9%]).

Conclusions and Clinical Relevance—Results indicated that unwanted horses donated to the EHC between 1996 and 2008 spanned a wide range of ages and breeds and included both males and females. The most common reason given for unwanted horses offered for donation during 2007 and 2008 was musculoskeletal disease, with degenerative joint disease, lameness of undetermined cause, laminitis, and navicular disease being the most common musculoskeletal conditions.

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in Journal of the American Veterinary Medical Association

Abstract

Objective—To identify factors associated with development of small colon impaction in horses and with selection of medical versus surgical treatment and to determine the prognosis for affected horses following medical or surgical management.

Design—Retrospective case series.

Animals—44 horses with primary impaction of the small colon.

Procedures—Medical records were reviewed for signalment, history, clinical findings, treatment (medical vs surgical), hospitalization time, and outcome. For comparison purposes, the same information was collected for 83 horses with primary impaction of the large colon.

Results—Diarrhea was the only factor found to be associated with development of small colon impaction. Horses with small colon impaction were 10.8 times as likely to have diarrhea at the time of initial examination as were horses with large colon impaction. Abdominal distension was the only factor associated with use of surgical versus medical treatment. Horses with small colon impaction that were treated surgically were 5.2 times as likely to have had abdominal distension at the time of admission as were horses with small colon impaction that were treated medically. Overall, 21 of 23 (91%) horses treated medically and 20 of 21 (95%) horses treated surgically survived to discharge.

Conclusions and Clinical Relevance—Results suggest that diarrhea may be a risk factor for development of small colon impaction and that horses with small colon impaction that have abdominal distension at the time of initial examination are more likely to require surgical than medical treatment.

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in Journal of the American Veterinary Medical Association

Abstract

Objective—To determine prevalence and risk factors for development of ileus of the large intestine after surgery in horses, identified by reduced postoperative fecal output (RPFO).

Design—Retrospective study.

Animals—37 horses that developed RPFO after undergoing general anesthesia for reasons unrelated to the gastrointestinal tract.

Procedure—Fecal output was obtained from medical records as number of defecations per 24-hour period after surgery; RPFO was defined as ≤ 3 defecations per 24-hour period after surgery. The reference population included 48 horses that defecated ≥ 4 times during the same period. Demographic, clinical, and surgical variables were evaluated for their association with development of RPFO by use of logistic regression analysis.

Results—Ten (12%) horses, all of which had RPFO, developed signs of colic after surgery. Horses ≥ 5 years old that underwent orthopedic procedures of > 60 minutes’ duration and that did not receive phenylbutazone after surgery were at significant risk for developing RPFO.

Conclusions and Clinical Relevance—Results suggest that after surgery unrelated to the gastrointestinal tract in horses, there is an intermediate clinical phase characterized by reduced fecal output preceding overt signs of colic. Recognition of RPFO may reduce morbidity and mortality of such horses. (J Am Vet Med Assoc 2001;218:414–420)

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in Journal of the American Veterinary Medical Association

Lidocaine hydrochloride is widely used in veterinary medicine as a local anesthetic and as an anti-arrhythmic for treatment of animals with ventricular tachycardia. 1,2 The use of systemicaUy administered lidocaine has increased dramatically in equine hospitals as a treatment for horses with intestinal ileus. 3,4,5 Lidocaine has novel anti-inflammatory properties that may also ameliorate the effects of ischemia-reperfu-sion injury 6-9 The purpose of the information reported here was to evaluate the current use of systemicaUy administered lidocaine in the treatment of horses with 2 specific gastrointestinal tract problems (ie, ileus and ischémie intestinal injury).

Pharmacologie Properties of
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in Journal of the American Veterinary Medical Association

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.

Full access
in American Journal of Veterinary Research

Abstract

OBJECTIVE To characterize epithelial cells of the small intestine and colon in horses without clinical gastrointestinal abnormalities with an emphasis on the stem cell niche constituents.

SAMPLE Mucosal biopsy specimens from small and large intestines obtained from 12 horses euthanized for reasons unrelated to gastrointestinal disease or systemic disease.

PROCEDURES Intestinal biopsy specimens were collected by sharp dissection immediately following euthanasia. Specimens were prepared for immunohistochemical, immunofluorescence, and transmission electron microscopic imaging to detect and characterize each epithelial cell type. Antibodies against protein biomarkers for cellular identification were selected on the basis of expression in other mammalian species.

RESULTS Intestinal epithelial cell types were identified by means of immunostaining and morphological characterization with transmission electron microscopy. Some differences in biomarker expression and antibody cross-reactivity were identified in equine tissue, compared with other species. However, each known type of mucosal epithelial cell was identified in equine tissue.

CONCLUSIONS AND CLINICAL RELEVANCE The methodology used can enhance detection of stem cells and progenitor cells as well as postmitotic cell lineages in equine intestinal tissues. Results may have relevance to regenerative potential of intestinal mucosa and survival in horses with colic.

Full access
in American Journal of Veterinary Research