@article{little_redding_gerard_2009, title={Osseous cyst-like lesions of the lateral infertubercular groove of the proximal humerus: A report of 5 cases}, volume={21}, ISSN={["2042-3292"]}, DOI={10.2746/095777308X382678}, abstractNote={Summary This report documents the case presentation, evaluation, treatment and outcome of 5 horses with an osseous cystlike lesion (OCLL) of the intertubercular groove of the proximal aspect of the humerus. In 3 of the 5 cases, delayed phase gamma scintigraphic findings demonstrated increased radiopharmaceutical uptake in the region of the intermediate tubercle of the proximal humerus of the affected limb, demonstrating increased bone remodelling in this region. In 4 of the 5 horses, an OCLL was identified in the intermediate tubercle of the proximal humerus, and in one horse the OCLL was identified in the greater tubercle. Medial‐lateral and craniomedial‐caudolateral oblique radiographic views were helpful to see the lesions in all cases. Ultrasonography confirmed the location of the subchondral and fibrocartilage defect associated with the OCLL and confirmed communication of the cyst with the lateral intertubercular groove of the humerus in 3 of the 5 cases. Ultrasonography also confirmed a variable degree of bicipital tendonitis in 3 of the horses. OCLL of the lateral intertubercular groove of the proximal humerus should be considered in the evaluation of any mature horse with lameness isolated to the bicipital bursa. Development of these OCLL may be a result of trauma or altered limb biomechanics as a result of shoulder osteoarthritis or concurrent chronic lameness, which leads to disruption or thinning of the fibrocartilage, remodelling of the subchondral bone and subsequent cyst development.}, number={2}, journal={EQUINE VETERINARY EDUCATION}, author={Little, D. and Redding, W. R. and Gerard, M. P.}, year={2009}, month={Feb}, pages={60–66} }
 @article{fogle_gerard_elce_little_morton_correa_blikslager_2008, title={Analysis of Sodium Carboxymethylcellulose Administration and Related Factors Associated with Postoperative Colic and Survival in Horses with Small Intestinal Disease}, volume={37}, ISSN={0161-3499 1532-950X}, url={http://dx.doi.org/10.1111/j.1532-950X.2008.00420.x}, DOI={10.1111/j.1532-950X.2008.00420.x}, abstractNote={Objective— To analyze the effect of the intraoperative use of sodium carboxymethylcellulose (CBMC) and related perioperative factors on postoperative colic and survival in horses that had abdominal surgery for colic. Study Design— Retrospective study. Animals— Horses (n=203) that had surgery for small intestinal disease; 33 horses had intraoperative administration of CBMC. Methods— Information was obtained from medical records for 170 horses that had surgery for colic before use of CBMC and 33 horses that had intraoperative CBMC. Kaplan–Meier survival curves were used to estimate median survival time and a Cox proportional hazards model was used to estimate the hazard ratio for the effect of CBMC and other perioperative variables on survival. Results— Seventy‐five percent of horses administered CBMC survived to 180 days, whereas 75% of untreated horses survived 8 days (median survival time=18 days). Horses not administered CBMC were twice as likely to die compared with horses administered CBMC. Horses that had postoperative ileus (POI) were 1.4 times more likely to die than horses without ileus. Similarly, horses with signs of colic after surgery were 1.3 times more likely to die than horses without postoperative signs of colic. Conclusions— CBMC administration is seemingly protective against death and prolongs survival when used intraoperatively in horses with small intestine disease, particularly horses with postoperative colic or POI. Both POI and colic increased risk of death after surgery. Clinical Relevance— Intraoperative administration of CBMC in horses that have surgery for small intestinal disease may improve survival, possibly by reducing early adhesion formation.}, number={6}, journal={Veterinary Surgery}, publisher={Wiley}, author={Fogle, Callie A. and Gerard, Mathew P. and Elce, Yvonne A. and Little, Dianne and Morton, Alison J. and Correa, Maria T. and Blikslager, Anthony T.}, year={2008}, month={Aug}, pages={558–563} }
 @article{little_jones_blikslager_2007, title={Cyclooxygenase (COX) Inhibitors and the Intestine}, volume={21}, ISSN={0891-6640 1939-1676}, url={http://dx.doi.org/10.1111/j.1939-1676.2007.tb02978.x}, DOI={10.1111/j.1939-1676.2007.tb02978.x}, abstractNote={Nonsteroidal anti‐inflammatory drugs (NSAIDs) have long been used for the treatment of pain and inflammation because of their inhibitory effects on cyclooxygenase (COX). For almost as long as NSAIDs have been in use, multiple adverse effects have been noted. Assessment of many of these adverse effects have been complicated because of the discovery of multiple splice variants of the cox gene, and a greater array of COX inhibitors, especially the COX‐2 selective inhibitors have become available. Some of these adverse effects cannot be readily explained by the effect of these drugs on COX. This has sparked a new field of investigation into the COX‐independent effects of the COX inhibitors. The major noncyclooxygenase targets of the COX inhibitors of particular relevance to inflammation and the gastrointestinal tract are phosphatidylinositol 3'‐kinase Akt signaling, uncoupling of oxidative phosphorylation, PPARγ, nuclear factor kB, mitogen activated protein kinases, and heat shock proteins.}, number={3}, journal={Journal of Veterinary Internal Medicine}, publisher={Wiley}, author={Little, Dianne and Jones, Samuel L. and Blikslager, Anthony T.}, year={2007}, month={May}, pages={367–377} }
 @article{little_brown_campbell_moeser_davis_blikslager_2007, title={Effects of the cyclooxygenase inhibitor meloxicam on recovery of ischemia-injured equine jejunum}, volume={68}, ISSN={0002-9645}, url={http://dx.doi.org/10.2460/ajvr.68.6.614}, DOI={10.2460/ajvr.68.6.614}, abstractNote={To determine the effect of meloxicam and flunixin meglumine on recovery of ischemia-injured equine jejunum.18 horses.Horses received butorphanol tartrate; were treated IV with saline (0.9% NaCl) solution (SS; 12 mL; n = 6), flunixin meglumine (1.1 mg/kg; 6), or meloxicam (0.6 mg/kg; 6) 1 hour before ischemia was induced for 2 hours in a portion of jejunum; and were allowed to recover for 18 hours. Flunixin and SS treatments were repeated after 12 hours; all 3 treatments were administered immediately prior to euthanasia. Selected clinical variables, postoperative pain scores, and meloxicam pharmacokinetic data were evaluated. After euthanasia, assessment of epithelial barrier function, histologic evaluation, and western blot analysis of ischemia-injured and control jejunal mucosa samples from the 3 groups were performed.Meloxicam- or flunixin-treated horses had improved postoperative pain scores and clinical variables, compared with SS-treated horses. Recovery of transepithelial barrier function in ischemia-injured jejunum was inhibited by flunixin but permitted similarly by meloxicam and SS treatments. Eighteen hours after cessation of ischemia, numbers of neutrophils in ischemia-injured tissue were higher in horses treated with meloxicam or flunixin than SS. Plasma meloxicam concentrations were similar to those reported previously, but clearance was slower. Changes in expression of proteins associated with inflammatory responses to ischemic injury and with different drug treatments occurred, suggesting cyclooxygenase-independent effects.Although further assessment is needed, these data have suggested that IV administration of meloxicam may be a useful alternative to flunixin meglumine for postoperative treatment of horses with colic.}, number={6}, journal={American Journal of Veterinary Research}, publisher={American Veterinary Medical Association (AVMA)}, author={Little, Dianne and Brown, S. Aubrey and Campbell, Nigel B. and Moeser, Adam J. and Davis, Jennifer L. and Blikslager, Anthony T.}, year={2007}, month={Jun}, pages={614–624} }
 @article{moeser_klok_ryan_wooten_little_cook_blikslager_2007, title={Stress signaling pathways activated by weaning mediate intestinal dysfunction in the pig}, volume={292}, ISSN={0193-1857 1522-1547}, url={http://dx.doi.org/10.1152/ajpgi.00197.2006}, DOI={10.1152/ajpgi.00197.2006}, abstractNote={Weaning in the piglet is a stressful event associated with gastrointestinal disorders and increased disease susceptibility. Although stress is thought to play a role in postweaning intestinal disease, the mechanisms by which stress influences intestinal pathophysiology in the weaned pig are not understood. The objectives of these experiments were to investigate the impact of weaning on gastrointestinal health in the pig and to assess the role of stress signaling pathways in this response. Nineteen-day-old pigs were weaned, and mucosal barrier function and ion transport were assessed in jejunal and colonic tissues mounted on Ussing chambers. Weaning caused marked disturbances in intestinal barrier function, as demonstrated by significant (P < 0.01) reductions in transepithelial electrical resistance and increases in intestinal permeability to [3H]mannitol in both the jejunum and colon compared with intestinal tissues from age-matched, unweaned control pigs. Weaned intestinal tissues exhibited increased intestinal secretory activity, as demonstrated by elevated short-circuit current that was sensitive to treatment with tetrodotoxin and indomethacin, suggesting activation of enteric neural and prostaglandin synthesis pathways in weaned intestinal tissues. Western blot analyses of mucosal homogenates showed increased expression of corticotrophin-releasing factor (CRF) receptor 1 in the jejunum and colon of weaned intestinal tissues. Pretreatment of pigs with the CRF receptor antagonist alpha-helical CRF(9-41), which was injected intraperitoneally 30 min prior to weaning, abolished the stress-induced mucosal changes. Our results indicate that weaning stress induces mucosal dysfunction mediated by intestinal CRF receptors and activated by enteric nerves and prostanoid pathways.}, number={1}, journal={American Journal of Physiology-Gastrointestinal and Liver Physiology}, publisher={American Physiological Society}, author={Moeser, Adam J. and Klok, Carin Vander and Ryan, Kathleen A. and Wooten, Jenna G. and Little, Dianne and Cook, Vanessa L. and Blikslager, Anthony T.}, year={2007}, month={Jan}, pages={G173–G181} }
 @article{davis_little_blikslager_papich_2006, title={Mucosal permeability of water-soluble drugs in the equine jejunum: a preliminary investigation}, volume={29}, ISSN={0140-7783 1365-2885}, url={http://dx.doi.org/10.1111/j.1365-2885.2006.00757.x}, DOI={10.1111/j.1365-2885.2006.00757.x}, abstractNote={Ussing chambers have been used to study the mucosal permeability of drugs in humans, rats and other species. This data can then be used to develop in vitro / in vivo correlations (IVIVC) for drugs based on the Biopharmaceutics Classification System (BCS). Due to the poor oral bioavailability of many drugs in the horse, this method may be useful for screening drugs before development to determine if they warrant further study. Cephalexin (CPX), marbofloxacin (MAR), metronidazole (MTZ) and fluconazole (FCZ) were chosen for this study based on the wide range of physicochemical properties and bioavailability in the horse. Permeability was ranked as follows: MTZ > FCZ > MAR > CPX. This correlated with the bioavailability ( R 2 = 0.633447), the Log P ( R 2 = 0.648517), as well as the molecular weight ( R 2 = 0.851208) of the drugs. Metronidazole induced a decrease in the tissue transepithelial resistance, suggestive of the possibility of tissue toxicity, which may have falsely increased its permeability. The low permeability of cephalexin across the tissue may indicate a lack of active transporters that are found in other species. From this study, we can conclude that the Ussing chamber is a promising method for determining mucosal permeability in the horse.}, number={5}, journal={Journal of Veterinary Pharmacology and Therapeutics}, publisher={Wiley}, author={Davis, J. L. and Little, D. and Blikslager, A. T. and Papich, M. G.}, year={2006}, month={Oct}, pages={379–385} }
 @article{brazik_luquire_little_2006, title={Pyrantel pamoate resistance in horses receiving daily administration of pyrantel tartrate}, volume={228}, DOI={10.2460/javma.228.1.101}, abstractNote={Abstract Case Descriptions —16 horses treated daily with pyrantel tartrate (2.64 mg/kg [1.2 mg/lb], PO) as part of a prophylactic anthelmintic program. Clinical Findings —Fecal worm egg counts (FWECs) were obtained on all 16 horses. Mean FWEC was 478 eggs/g (epg; range, 0 to 4,075 epg). Three of the 16 horses were responsible for 85% of the total fecal egg output for the herd on the day of sampling. Six horses had FWECs < 200 epg. Three horses that had arrived within 4 months of the sampling date had FWECs < 100 epg. Treatment and Outcome —An FWEC reduction test was initiated the day after FWECs were obtained; all horses with FWECs > 100 epg (9 horses) were treated with pyrantel pamoate (6.6 mg/kg [3 mg/lb], PO), and 14 days later, the FWEC was repeated. During the 14-day period, all horses received pyrantel tartrate (2.64 mg/kg, PO) daily. Fecal worm egg count reduction was calculated for each horse. Mean FWEC reduction for the group was 28.5% (range, increase of 21% in FWECs 14 days after treatment to a decrease of 100% in FWEC 14 days after treatment). Clinical Relevance —Farms should be monitored for cyathostomes resistant to pyrantel pamoate prior to use of pyrantel tartrate. Fecal worm egg counts should be monitored routinely in horses before and after treatment to ensure efficacy of cyathostome control measures.}, number={1}, journal={Journal of the American Veterinary Medical Association}, author={Brazik, E. L. and Luquire, J. T. and Little, D.}, year={2006}, pages={101–103} }
 @article{tschetter_blikslager_little_howard_woody_beex_crisman_2005, title={Detection of differentially regulated genes in ischaemic equine intestinal mucosa}, volume={37}, ISSN={["0425-1644"]}, DOI={10.2746/0425164054529382}, abstractNote={Reasons for performing study: Colic is a serious disease syndrome in horses. Much of the mortality is associated with ischaemic-injured intestine during strangulating obstruction, yet there is limited understanding of the associated molecular events. Identification of differentially expressed genes during ischaemic injury should expand our understanding of colic and may lead to novel targeted therapeutic approaches in the future. Objective: To isolate and identify differentially expressed genes in equine jejunum following a 2 h ischaemic event compared to normally perfused jejunum. Methods: Suppressive subtractive hybridisation was used to clone genes that are differentially expressed in equine jejunum injured by 2 h of complete ischaemia as compared to time-matched control jejunal tissues. Expression of selected clones was further evaluated by northern blot analysis. Results: Of the 384 clones selected, 157 were confirmed to possess cDNAs corresponding differentially expressed genes by dot blot analysis. Two genes, fatty acid binding protein 2 and calcium-activated chloride channel 4 were further confirmed to be differentially expressed by northern blot analysis. Conclusions: Suppressive subtractive hybridisation can be used to detect changes in expression of a broad array of genes, as confirmed by northern blot analysis of selected genes. Potential relevance: These initial results have identified a pool of equine intestinal epithelial genes that are differentially expressed following a 2 h ischaemic event. In particular, genes indicative of deranged metabolic activity and those potentially involved in early repair events were identified and may ultimately provide clues as to the nature of epithelial ischaemic injury in horses.}, number={4}, journal={EQUINE VETERINARY JOURNAL}, author={Tschetter, JR and Blikslager, AT and Little, D and Howard, RD and Woody, SL and Beex, LM and Crisman, MV}, year={2005}, month={Jul}, pages={319–324} }
 @article{little_white_young_blikslager_2005, title={Faecal bile loss in horses following small intestinal resection}, volume={37}, ISSN={["0425-1644"]}, DOI={10.2746/0425164054406883}, abstractNote={Equine Veterinary JournalVolume 37, Issue 1 p. 92-94 Faecal bile loss in horses following small intestinal resection D. LITTLE, D. LITTLE Department of Clinical Sciences, College of Veterinary Medicine, North Carolina State University, 4700 Hillsborough Street, Raleigh, North Carolina 27606, USASearch for more papers by this authorC. E. WHITE, C. E. WHITE Department of Clinical Sciences, College of Veterinary Medicine, North Carolina State University, 4700 Hillsborough Street, Raleigh, North Carolina 27606, USASearch for more papers by this authorK. M. YOUNG, K. M. YOUNG Department of Clinical Sciences, College of Veterinary Medicine, North Carolina State University, 4700 Hillsborough Street, Raleigh, North Carolina 27606, USASearch for more papers by this authorA. T. BLIKSLAGER, Corresponding Author A. T. BLIKSLAGER Department of Clinical Sciences, College of Veterinary Medicine, North Carolina State University, 4700 Hillsborough Street, Raleigh, North Carolina 27606, USADepartment of Clinical Sciences, College of Veterinary Medicine, North Carolina State University, 4700 Hillsborough Street, Raleigh, North Carolina 27606, USASearch for more papers by this author D. LITTLE, D. LITTLE Department of Clinical Sciences, College of Veterinary Medicine, North Carolina State University, 4700 Hillsborough Street, Raleigh, North Carolina 27606, USASearch for more papers by this authorC. E. WHITE, C. E. WHITE Department of Clinical Sciences, College of Veterinary Medicine, North Carolina State University, 4700 Hillsborough Street, Raleigh, North Carolina 27606, USASearch for more papers by this authorK. M. YOUNG, K. M. YOUNG Department of Clinical Sciences, College of Veterinary Medicine, North Carolina State University, 4700 Hillsborough Street, Raleigh, North Carolina 27606, USASearch for more papers by this authorA. T. BLIKSLAGER, Corresponding Author A. T. BLIKSLAGER Department of Clinical Sciences, College of Veterinary Medicine, North Carolina State University, 4700 Hillsborough Street, Raleigh, North Carolina 27606, USADepartment of Clinical Sciences, College of Veterinary Medicine, North Carolina State University, 4700 Hillsborough Street, Raleigh, North Carolina 27606, USASearch for more papers by this author First published: 05 January 2010 https://doi.org/10.2746/0425164054406883Citations: 3AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat No abstract is available for this article.Citing Literature Volume37, Issue1January 2005Pages 92-94 RelatedInformation}, number={1}, journal={EQUINE VETERINARY JOURNAL}, author={Little, D and White, CE and Young, KM and Blikslager, AT}, year={2005}, month={Jan}, pages={92–94} }
 @article{little_tomlinson_blikslager_2005, title={Post operative neutrophilic inflammation in equine small intestine after manipulation and ischaemia}, volume={37}, ISSN={["0425-1644"]}, DOI={10.2746/0425164054529472}, abstractNote={Reasons for performing study: Post operative ileus (POI) remains an important cause of post operative morbidity and mortality in the horse. However, clinical progression of naturally occurring cases of POI in both horse and man does not entirely support the 'neurogenic' hypothesis as the sole mechanism of POI; and the hypothesis that inflammation plays a major role at 12–24 h after surgery requires validation. Hypothesis: An inflammatory infiltrate in the muscularis externa and myenteric plexus of equine jejunum is present 18 h following a period of ischaemia. Methods: Samples of normal jejunum, jejunum from the proximal resection margins of clinical cases and jejunum obtained 18 h after 1 or 2 h ischaemia or manipulation alone were evaluated for neutrophil infiltration. Samples obtained 18 h after surgery were additionally evaluated for leucocyte activation using calprotectin immunohistochemistry. Results were evaluated by ANOVA and P0.05 was considered significant. Results: Significant neutrophilic inflammation was identified in the samples from the proximal resection margins of clinical cases compared to uninjured jejunum. In experimental cases, neutrophilic inflammation appeared to be increased further by 18 h and was identified through all intestinal layers, particularly in the serosa, fascial planes around circular and longitudinal muscle fibres, and myenteric plexus. This elevated level of neutrophilic inflammation was mirrored by an increased number of calprotectin-positive cells in these intestinal layers, indicating leucocyte activation. Conclusions: Significant neutrophilic inflammation occurs in equine jejunal myenteric layers 18 h after surgery. Potential relevance: This neutrophilic inflammation coincides with the clinical time point at which POI is identified and may indicate that inflammatory pathways, rather than solely neurogenic pathways, are responsible for POI in the horse.}, number={4}, journal={EQUINE VETERINARY JOURNAL}, author={Little, D and Tomlinson, JE and Blikslager, AT}, year={2005}, month={Jul}, pages={329–335} }
 @article{moeser_haskell_shifflett_little_schultz_blikslager_2004, title={CIC-2 chloride secretion mediates prostaglandin-induced recovery of barrier function in ischemia-injured porcine ileum}, volume={127}, ISSN={["1528-0012"]}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-4444353665&partnerID=MN8TOARS}, DOI={10.1053/j.gastro.2004.06.004}, abstractNote={Background & Aims Ischemia results in the breakdown of the intestinal barrier, predisposing patients to sepsis and multiple organ failure. Prostaglandins play a critical role in mediating recovery of barrier function in ischemia-injured intestine through a mechanism involving stimulation of Cl− secretion. In the present study, we investigated the contributory role of individual Cl− channels in the recovery of barrier function in ischemia-injured porcine ileum. Methods Ischemia-injured porcine ileal mucosa was mounted in Ussing chambers. Short-circuit current (Isc) and transepithelial resistance (TER) were measured in response to prostaglandin E2 (PGE2) and pharmacologic inhibitors of epithelial Cl− channels. Immunoassays were used to assess the expression and localization of ion channels. Results Application of PGE2 to ischemia-injured ileal mucosa stimulated increases in Isc, an indicator of Cl− secretion, that was followed by marked increases in TER, an indicator of barrier function recovery. In vitro studies revealed that although PGE2 induced Cl− secretion via at least 3 distinct secretory pathways, recovery of barrier function was initiated by Cl− secretion via ClC-2 Cl− channels co-expressed with occludin and localized to tight junctions within restituting epithelium. Intravenous administration of furosemide to pigs subjected to 1 hour of ileal ischemia impaired recovery of barrier function, as evidenced by decreased TER and increased mucosal-to-serosal 3H-mannitol flux after a 2-hour reperfusion/recovery period, confirming an important role for Cl− secretory pathways in vivo. Conclusions ClC-2–mediated intestinal Cl− secretion restores TER in ischemia-injured intestine. These data may provide the basis for targeted pharmacologic therapy for diseases associated with impaired barrier function. Background & Aims Ischemia results in the breakdown of the intestinal barrier, predisposing patients to sepsis and multiple organ failure. Prostaglandins play a critical role in mediating recovery of barrier function in ischemia-injured intestine through a mechanism involving stimulation of Cl− secretion. In the present study, we investigated the contributory role of individual Cl− channels in the recovery of barrier function in ischemia-injured porcine ileum. Methods Ischemia-injured porcine ileal mucosa was mounted in Ussing chambers. Short-circuit current (Isc) and transepithelial resistance (TER) were measured in response to prostaglandin E2 (PGE2) and pharmacologic inhibitors of epithelial Cl− channels. Immunoassays were used to assess the expression and localization of ion channels. Results Application of PGE2 to ischemia-injured ileal mucosa stimulated increases in Isc, an indicator of Cl− secretion, that was followed by marked increases in TER, an indicator of barrier function recovery. In vitro studies revealed that although PGE2 induced Cl− secretion via at least 3 distinct secretory pathways, recovery of barrier function was initiated by Cl− secretion via ClC-2 Cl− channels co-expressed with occludin and localized to tight junctions within restituting epithelium. Intravenous administration of furosemide to pigs subjected to 1 hour of ileal ischemia impaired recovery of barrier function, as evidenced by decreased TER and increased mucosal-to-serosal 3H-mannitol flux after a 2-hour reperfusion/recovery period, confirming an important role for Cl− secretory pathways in vivo. Conclusions ClC-2–mediated intestinal Cl− secretion restores TER in ischemia-injured intestine. These data may provide the basis for targeted pharmacologic therapy for diseases associated with impaired barrier function. The intestinal epithelium serves a divergent role in gastrointestinal function. On one hand, the intestinal epithelium facilitates the efficient transport of water and nutrients across the epithelium while on the other hand it forms a selective barrier that restricts potentially pathogenic luminal microorganisms and their products from traversing the epithelium and gaining entry into the subepithelial tissues and circulation.1Gerwitz A.T. Liu Y. Sitaraman S.V. Madara J.L. Intestinal epithelial pathobiology past, present, and future.Best Pract Res Gastroenterol. 2002; 16: 851-867Abstract Full Text PDF PubMed Scopus (50) Google Scholar Disruption of the intestinal barrier is a sequela to a number of gastrointestinal diseases including inflammatory bowel disease, ischemia-reperfusion injury, nonsteroidal anti-inflammatory drug-induced gastropathy, and assault by enteric pathogens.2Berkes J. Viswanathan V.K. Savkovic S.D. Hecht G. Intestinal epithelial responses to enteric pathogens effects on the tight junction barrier, ion transport, and inflammation.Gut. 2000; 52: 439-451Crossref Scopus (461) Google Scholar, 3DeMeo M.T. Mutlu E.A. Keshavarzian A. Tobin M.C. Intestinal permeation and gastrointestinal disease.J Clin Gastroenterol. 2002; 34: 385-396Crossref PubMed Scopus (234) Google Scholar, 4Hawkey C.J. Non-steroidal anti-inflammatory drug gastropathy.Gastroenterology. 2000; 119: 521-535Abstract Full Text Full Text PDF PubMed Scopus (305) Google Scholar Furthermore, there is a direct association between impaired barrier function and the onset of sepsis and multiple organ failure.5Deitch E.A. Rutan R. Waymack J.P. Trauma, shock, and gut translocation.New Horizons. 1996; 4: 289-299PubMed Google Scholar, 6Moore F.A. Moore E.E. Evolving concepts in the pathogenesis of postinjury multiple organ failure.Surg Clin North Am. 1995; 75: 257-277Abstract Full Text PDF PubMed Scopus (459) Google Scholar Prostaglandins (PGs) are metabolites of arachidonic acid formed through a cyclooxygenase-dependent pathway and are produced, in part, as a response to intestinal injury and breakdown of barrier function.7Argenzio R.A. Lecce J. Powell D.W. Prostanoids inhibit intestinal NaCl absorption in experimental porcine cryptosporidiosis.Gastroenterology. 1993; 104: 440-471PubMed Google Scholar, 8Eckmann L. Stenson W.F. Savidge T.C. Lowe D.C. Barrett K.E. Fierer J. Smith J.R. Kagnoff M.F. Role of intestinal epithelial cells in the host secretory response to infection by invasive bacteria Bacterial entry induces epithelial prostaglandin h synthase-2 expression and prostaglandin E2 and F2alpha production.J Clin Invest. 1997; 100: 296-309Crossref PubMed Scopus (174) Google Scholar PGs are potent mediators of inflammation and intestinal fluid secretion.9Smith W.L. DeWitt D.L. Prostaglandin endoperoxidase H synthases-1 and -2.Adv Immunol. 1996; 62: 167-215Crossref PubMed Google Scholar, 10Appleton I. Tomlinson A. Willoughby D.A. Induction of cyclo-oxygenase and nitric oxide synthase in inflammation.Adv Pharmacol. 1996; 35: 27-78Crossref PubMed Scopus (122) Google Scholar, 11Calderaro V. Rossi F. Intestinal chloride secretion cyclic AMP and Ca2+ interactions.in: Gaginella T.S. Regulatory mechanisms in gastrointestinal function. 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Prostaglandin biology in inflammatory bowel disease.Gastroenterol Clin North Am. 2001; 30: 971-980Abstract Full Text Full Text PDF PubMed Scopus (93) Google Scholar The latter effect has been shown by the ability of PGs to induce Cl− secretion and secretory diarrhea in both in vitro and in vivo models.16Gaginella T.S. Eicosanoid-mediated intestinal secretion.in: Lenethal E. Duffy M. Textbook of secretory diarrhea. Raven, New York1990: 15-30Google Scholar, 17Eberhart C.E. DuBois R.N. Eicosanoids and the gastrointestinal tract.Gastroenterology. 1995; 109: 285-301Abstract Full Text PDF PubMed Scopus (406) Google Scholar, 18Lanza F.L. Kochman R.L. Geis G.S. Rack E.M. Deysach L.G. A double-blind, placebo-controlled, 6-day evaluation of two doses of misoprostol in gastroduodenal mucosal protection against damage from aspirin and effects on bowel habits.Am J Gastroenterol. 1991; 86: 1743-1748PubMed Google Scholar Despite the negative implications associated with excessive PG production, a low level of PG synthesis is required for normal gut function. This apparent PG tone is involved in the maintenance of gastrointestinal protective functions such as stimulation of epithelial mucus and bicarbonate secretion, regulation of mucosal blood flow, and induction of epithelial cell proliferation.17Eberhart C.E. DuBois R.N. Eicosanoids and the gastrointestinal tract.Gastroenterology. 1995; 109: 285-301Abstract Full Text PDF PubMed Scopus (406) Google Scholar, 19Wallace J.L. Bell C.J. Gastromucosal defense.Curr Opin Gastroenterol. 1996; 12: 503-511Crossref Scopus (23) Google Scholar The cytoprotective role of PGs is evidenced clearly by the gastrointestinal tract injury induced by chronic nonsteroidal anti-inflammatory drug therapy.20Bjarnason I. Williams P. Smethurst P. Peters T.J. Levi A.J. The effect of NSAIDs and prostaglandins on the permeability of the human small intestine.Gut. 1986; 27: 1292-1297Crossref PubMed Scopus (240) Google Scholar, 21Graumlich J.F. Preventing gastrointestinal complications of NSAIDs risk factors, recent advances, and latest strategies.Postgrad Med. 2001; 109: 117-128Crossref PubMed Scopus (29) Google Scholar We previously have shown a critical role of PGs in the recovery of barrier function in injured intestine.22Blikslager A.T. Roberts M.C. Rhoads M.J. Argenzio R.A. Prostaglandins I2 and E2 have a synergistic role in rescuing epithelial barrier function in porcine ileum.J Clin Invest. 1997; 100: 1928-1933Crossref PubMed Scopus (112) Google Scholar, 23Blikslager A.T. Roberts M.C. Argenzio R.A. Prostaglandin-induced recovery of barrier function in porcine ileum is triggered by chloride secretion.Am J Physiol. 1999; 276: G28-G36PubMed Google Scholar, 24Little D. Dean R.A. Young K.M. McKane S.A. Martin L.D. Jones S.L. Blikslager A.T. PI3K signaling is required for prostaglandin-induced mucosal recovery in ischemia-injured porcine ileum.Am J Physiol. 2003; 284: G46-G56Google Scholar, 25Gookin J.L. Galanko J.A. Blikslager A.T. Argenzio R.A. Prostaglandin-mediated closure of paracellular pathway and not restitution is the primary determinant of barrier recovery in acutely injured porcine ileum.Am J Physiol. 2003; 285: G967-G979Google Scholar This is based on evidence that treatment of acutely injured porcine ileum with the nonsteroidal anti-inflammatory drug indomethacin significantly impaired the ability of the intestine to recover barrier function, as measured by the recovery of transepithelial electrical resistance (TER). Furthermore, application of exogenous PGs to injured mucosa rapidly restored TER, an effect associated with the closure of the paracellular space. PGs stimulate cyclic adenosine monophosphate-dependent Cl− secretion and inhibit electroneutral Na+ absorption,7Argenzio R.A. Lecce J. Powell D.W. Prostanoids inhibit intestinal NaCl absorption in experimental porcine cryptosporidiosis.Gastroenterology. 1993; 104: 440-471PubMed Google Scholar, 26Halm D.R. Rechkemmer G.R. Schoumacher R.A. Frizzell R.A. Apical membrane chloride channels in a colonic cell line activated by secretory agonists.Am J Physiol. 1998; 254: C505-C611Google Scholar both of which represent critical components of the resealing process of the tight junctions after injury.23Blikslager A.T. Roberts M.C. Argenzio R.A. Prostaglandin-induced recovery of barrier function in porcine ileum is triggered by chloride secretion.Am J Physiol. 1999; 276: G28-G36PubMed Google Scholar We hypothesize that increases in TER induced by PGs are a result of a signaling pathway involving an osmotic gradient triggered by luminal accumulation of Cl− and Na+. The detailed mechanisms by which PGs alter electrolyte transport and trigger recovery of barrier function have not been characterized fully. Therefore, the objective of the present experiments was to define further the mechanisms through which PGs alter electrolyte transport in the ischemia-injured intestine, specifically assessing the role of individual Cl− channels in restoration of barrier function. Our data indicate that although PGE2-induced Cl− secretion is mediated through at least 3 epithelial Cl− channels in ischemia-injured porcine ileum, restoration of barrier function involves a distinct Cl− secretory event mediated through ClC-2 Cl− channels, expressed in the interepithelial tight junctions. All studies were approved by the North Carolina State University Institutional Animal Care and Use Committee. Six- to 8-week-old Yorkshire cross-bred pigs of either sex were housed individually, and maintained on a commercial pelleted feed. Pigs were held off feed for 24 hours before experimental surgery. General anesthesia was induced with xylazine (1.5 mg/kg, intramuscularly), ketamine (11 mg/kg, intramuscularly), and thiopental (15 mg/kg, intravenously), and maintained with intermittent infusion of thiopental (6–8 mg/kg/h), as previously described.22Blikslager A.T. Roberts M.C. Rhoads M.J. Argenzio R.A. Prostaglandins I2 and E2 have a synergistic role in rescuing epithelial barrier function in porcine ileum.J Clin Invest. 1997; 100: 1928-1933Crossref PubMed Scopus (112) Google Scholar, 24Little D. Dean R.A. Young K.M. McKane S.A. Martin L.D. Jones S.L. Blikslager A.T. PI3K signaling is required for prostaglandin-induced mucosal recovery in ischemia-injured porcine ileum.Am J Physiol. 2003; 284: G46-G56Google Scholar The ileum was approached via a ventral midline incision. Ileal segments were delineated by ligating the intestine at 10-cm intervals, and subjected to ischemia by occluding the local mesenteric blood supply for 45 minutes. After the 45-minute ischemic period, tissues were harvested from the pig and the mucosa was stripped from the seromuscular layer in oxygenated (95% O2/5% CO2) Ringer’s solution. Tissues then were mounted in 3.14-cm2 aperture Ussing chambers, as described in previous studies.27Argenzio R.A. Liacos J.A. Endogenous prostanoids control ion transport across neonatal porcine ileum in vitro.Am J Vet Res. 1990; 51: 747-751PubMed Google Scholar For each Ussing chamber experiment, ileal tissues from one pig were mounted on multiple Ussing chambers. Tissue segments were mounted randomly in Ussing chambers without reference to their location along the length of the ileum. Each tissue was subjected to a different in vitro treatment. Tissues were bathed on the serosal and mucosal sides with 10 mL of Ringer’s solution. The serosal bathing solution contained 10 mmol/L glucose, and was balanced osmotically on the mucosal side with 10 mmol/L mannitol. Bathing solutions were oxygenated (95% O2/5% CO2) and circulated in water-jacketed reservoirs. The spontaneous potential difference was measured using Ringer-agar bridges connected to calomel electrodes, and the potential difference was short-circuited through Ag-AgCl electrodes using a voltage clamp that corrected for fluid resistance. TER (Ω · cm2) was calculated from the spontaneous potential difference and short-circuit current (Isc), as previously described.22Blikslager A.T. Roberts M.C. Rhoads M.J. Argenzio R.A. Prostaglandins I2 and E2 have a synergistic role in rescuing epithelial barrier function in porcine ileum.J Clin Invest. 1997; 100: 1928-1933Crossref PubMed Scopus (112) Google Scholar, 24Little D. Dean R.A. Young K.M. McKane S.A. Martin L.D. Jones S.L. Blikslager A.T. PI3K signaling is required for prostaglandin-induced mucosal recovery in ischemia-injured porcine ileum.Am J Physiol. 2003; 284: G46-G56Google Scholar For experiments assessing the role of Cl− channels in the PGE2-induced recovery of barrier function, tissues were pretreated (t = 0 min) with pharmacologic Cl− channel inhibitors on the appropriate surface and then treated with PGE2 (10−6 mol/L) on the serosal side of the tissue (t = 30 min). For each in vitro experiment, a total of 6 pigs were used (n = 6). For each pig, multiple mucosal samples were harvested and mounted in Ussing chambers, with each tissue exposed to a distinct treatment. A total of 12 pigs were used for in vivo recovery experiments. For each experiment, general anesthesia was induced in 2 pigs with xylazine (1.5 mg/kg, intramuscularly) and ketamine (11 mg/kg, intramuscularly). Pigs then were intubated and maintained on isoflurane throughout the duration of the experiment. Pigs were placed on heating pads and lactated Ringer’s solution was administered intravenously at a maintenance rate of 15 mL/kg/h. Body temperature, heart rate, and respiration were measured throughout the experiment. Intestinal injury was induced by cross-clamping 10-cm segments of ileum, and clamping local vasculature for 1 hour, after which the clamps were removed, and the intestine was allowed to reperfuse for 2 hours. Pigs remained anesthetized for the entire experiment. Just before reperfusion, furosemide (1 mg/kg, intravenously) was administered to one of each of the pairs of pigs while the other pig received an equal volume of saline and served as a control. At the end of the 2-hour recovery period the pigs were euthanized. Ileal tissues were harvested and mounted on Ussing chambers for determination of TER and mucosal-to-serosal flux of 3H-mannitol. To assess transmucosal Na+ and Cl− fluxes, 22Na or 36Cl were added to the mucosal or serosal solutions of tissues paired according to their conductance (conductance within 25% of each other). After a 15-minute equilibration period and before addition of treatments, standards were taken from the bathing reservoirs. Thirty minutes after the addition of treatments, 3 successive 60-minute flux periods (from 30 to 210 minutes of the experiments) were performed by taking samples from the bathing reservoirs opposite the side of isotope addition. Samples were counted for 22Na and 36Cl in a liquid scintillation counter, and unidirectional fluxes were calculated as previously described.7Argenzio R.A. Lecce J. Powell D.W. Prostanoids inhibit intestinal NaCl absorption in experimental porcine cryptosporidiosis.Gastroenterology. 1993; 104: 440-471PubMed Google Scholar Similar methods were used to quantify mucosal-to-serosal fluxes of 3H-labeled mannitol. Tissues were taken at 0, 60, and 240 minutes for routine histologic evaluation. Tissues were sectioned (5 μm) and stained with H&E. For each tissue, 3 sections were evaluated. Four well-oriented villi were identified in each section, and the villus height and the height of the epithelial-covered portion of each villus were measured. The percentage of the villous surface area that remained denuded was calculated from the total surface area of the villus and the surface area of the villus covered by epithelium, as previously described.7Argenzio R.A. Lecce J. Powell D.W. Prostanoids inhibit intestinal NaCl absorption in experimental porcine cryptosporidiosis.Gastroenterology. 1993; 104: 440-471PubMed Google Scholar Ileal scrapings from control and ischemia-injured mucosa were snap-frozen and stored at −70°C before sodium dodecyl sulfate—polyacrylamide gel electrophoresis (SDS-PAGE). Tissue aliquots were thawed at 4°C and added to 3 mL of chilled lysis buffer, including protease inhibitors at 4°C, as previously described. This mixture was homogenized on ice and then centrifuged at 4°C, and the supernatant was saved. Protein analysis of extract aliquots was performed (DC Protein Assay; Bio-Rad, Hercules, CA). Tissue extracts (amounts equalized by protein concentration) were mixed with an equal volume of 2× SDS-PAGE sample buffer and boiled for 4 minutes. Lysates were loaded on a 10% SDS-polyacrylamide gel, and electrophoresis was performed according to standard protocols. Proteins were transferred to a nitrocellulose membrane (Hybond ECL; Amersham Life Science, Birmingham, UK) by using an electroblotting minitransfer apparatus. Membranes were blocked at room temperature for 60 minutes in Tris-buffered saline plus 0.05% Tween 20 and 5% dry powdered milk. Membranes were washed and incubated with primary antibody (rabbit ClC-2 polyclonal antibody; Alpha Diagnostic International, San Antonio, TX; or rabbit cystic fibrosis transmembrane conductance regulator [CFTR] polyclonal antibody; Research Diagnostics Inc, Flanders, NJ). After additional washing, membranes were incubated with horseradish peroxidase-conjugated secondary antibody, and developed for visualization of protein by the addition of enhanced chemiluminescence reagent (Amersham, Piscataway, NJ) as previously described.24Little D. Dean R.A. Young K.M. McKane S.A. Martin L.D. Jones S.L. Blikslager A.T. PI3K signaling is required for prostaglandin-induced mucosal recovery in ischemia-injured porcine ileum.Am J Physiol. 2003; 284: G46-G56Google Scholar Densitometry analysis was performed by using appropriate software (IP gel; Scanalytics, Fairfax, VA). Tissue extracts were prepared according to the Western blotting protocol described previously.24Little D. Dean R.A. Young K.M. McKane S.A. Martin L.D. Jones S.L. Blikslager A.T. PI3K signaling is required for prostaglandin-induced mucosal recovery in ischemia-injured porcine ileum.Am J Physiol. 2003; 284: G46-G56Google Scholar Extracted proteins (500 μg) were solubilized in RIPA buffer with protease inhibitors and incubated with rabbit ClC-2 polyclonal antibody (5 μg/mL) for 1 hour at 37°C. The antibody-protein complexes were adsorbed from solution with protein A/G-Agarose beads (Santa Cruz Biotechnology, Santa Cruz, CA). Protein samples were washed 3× in ice-cold RIPA buffer and centrifuged at 25,000 × g for 1 minute at 4°C. Protein pellets were solubilized in 2× SDS-PAGE sample buffer and electrophoresis was performed according to standard procedures described previously.24Little D. Dean R.A. Young K.M. McKane S.A. Martin L.D. Jones S.L. Blikslager A.T. PI3K signaling is required for prostaglandin-induced mucosal recovery in ischemia-injured porcine ileum.Am J Physiol. 2003; 284: G46-G56Google Scholar Nitrocellulose membranes were incubated with anti-ClC-2 (50 μg/mL). For co-immunoprecipitation experiments, immunoprecipitated ClC-2 or rabbit pre-immune serum were subjected to SDS-PAGE and probed using an occludin antibody (2 μg/mL; Santa Cruz Biotechnology). Immunofluorescence labeling was performed on ileal tissues that were embedded in optimal cutting temperature medium, frozen, sectioned at 5-μm thickness, and fixed in cold acetone. Tissue sections were blocked with 2% bovine serum albumin before incubation with rabbit anti-ClC-2 polyclonal antibody (40 μg/mL) in BLOTTO (Bovine Lacto Transfer Technique Optimizer) for 2 hours at 4°C. Sections were washed with BLOTTO and incubated for 45 minutes with Cy3-conjugated anti-rabbit secondary antibody (1:300; Zymed Laboratories Inc., San Francisco, CA) in the dark. Sections were washed in phosphate-buffered saline, mounted, cover slipped, and viewed with an immunofluorescence microscope. Ileal tissues were fixed in 4% formaldehyde and processed for transmission electron microscopy using standard techniques.28Dykstra M.J. A manual of applied techniques for biological electron microscopy. Plenum Press, New York1993Crossref Google Scholar In brief, tissue samples were dehydrated in a graded ethanol series. Tissues were placed in fresh LR white resin (Electron Microscopy Sciences, Fort Washington, PA) in gelatin capsules and polymerized at 55°C-60°C overnight. Ultrathin sections (80–90 nm) were mounted on stainless steel grids (Electron Microscopy Sciences, Fort Washington, PA). For immunolocalization, grid sections were blocked in 5% normal goat serum (Biogenix, San Ramon, CA) before incubation with rabbit anti-ClC-2 polyclonal antibody (200 μg/mL) for 1 hour. Sections were washed and incubated with gold-conjugated anti-rabbit immunoglobulin G secondary antibody (Sigma, St. Louis, MO; 10-nm particle size) in normal goat serum for 1 hour. Tissue sections were rinsed with phosphate-buffered saline, dried, and stained with 1% methanolic uranyl acetate and viewed on an electron microscope (Phillips/FEICO Model 208s Transmission Electron Microscope; Hillsboro, OR). Indomethacin, 16,16 dimethyl PGE2, 4,4′-diaminostilbene-2,2′-disulfonic acid (DNDS), cadmium chloride (CdCl2), zinc chloride (ZnCl2), bumetanide, PD-098,059, and 5-nitro 2-(3-phenylpropylamino) benzoic acid were purchased from Sigma Chemical. N-(4-methylphenylsulfonyl)-N′-(4-trifluoromethylphenyl)urea (DASU-02) can be obtained from B. D. Schultz (Kansas State University, Manhattan, KS). Data were reported as means ± SE based on the experimental number (n). All data were analyzed by using an analysis of variance (ANOVA) for repeated measures, except when the peak response was analyzed by using a standard one-way ANOVA (Sigmastat; Jandel Scientific, San Rafael, CA). A Tukey’s test was used to determine differences between treatments after ANOVA. Forty-five minutes of intestinal ischemia resulted in diminished TER values compared with nonischemic control tissue (27 ± 1.1 Ω · cm2 in ischemic tissue vs. 53 ± 2.5 Ω · cm2 in control tissue), which is indicative of impaired barrier function. Application of 10−6 mol/L PGE2 to the serosal side of ischemia-injured mucosa resulted in rapid and significant (P < 0.01) restoration of TER (▵TER = 26 Ω · cm2, Figure 1A), achieving control levels within 30 minutes of PGE2 application. In line with previous observations,23Blikslager A.T. Roberts M.C. Argenzio R.A. Prostaglandin-induced recovery of barrier function in porcine ileum is triggered by chloride secretion.Am J Physiol. 1999; 276: G28-G36PubMed Google Scholar, 24Little D. Dean R.A. Young K.M. McKane S.A. Martin L.D. Jones S.L. Blikslager A.T. PI3K signaling is required for prostaglandin-induced mucosal recovery in ischemia-injured porcine ileum.Am J Physiol. 2003; 284: G46-G56Google Scholar PGE2-induced increases in TER were preceded by sharp and significant (P < 0.01) increases in short circuit current (▵Isc = 22 μA/cm2, Figure 1B, C), an indicator of electrogenic Cl− secretion. Histologic (Figure 2) and morphometric (Table 1) evaluation of ischemia-injured mucosa revealed a significant decrease in villus height (160 ± 20 μm in control vs. 100 ± 30 μm in ischemic tissue) and a significant denuding of ischemic mucosa (30% ± 2.7% denuded villus surface area). Denuded villous tips were near-fully restituted within 60 minutes from the time they were mounted in Ussing chambers (Table 1). Furthermore, restitution was not enhanced by administration of PGE2, and treatment with indomethacin alone did not retard restitution. Given these results, we concluded that the significant increases in TER in the presence of PGE2 were attributable to changes in paracellular rather than transcellular resistance, as has been shown in previous studies.23Blikslager A.T. Roberts M.C. Argenzio R.A. Prostaglandin-induced recovery of barrier function in porcine ileum is triggered by chloride secretion.Am J Physiol. 1999; 276: G28-G36PubMed Google Scholar, 24Little D. Dean R.A. Young K.M. McKane S.A. Martin L.D. Jones S.L. Blikslager A.T. PI3K signaling is required for prostaglandin-induced mucosal recovery in ischemia-injured porcine ileum.Am J Physiol. 2003; 284: G46-G56Google Scholar, 25Gookin J.L. Galanko J.A. Blikslager A.T. Argenzio R.A. Prostaglandin-mediated closure of paracellular pathway and not restitution is the primary determinant of barrier recovery in acutely injured porcine ileum.Am J Physiol. 2003; 285: G967-G979Google ScholarTable 1Morphometric Assessment of Epithelial Restitution in Ischemia-Injured Porcine Ileal MucosaTreatmentRecovery time (min)Epithelial surface area denuded (%)Villus height (mm)Nonischemic control000.16 ± 0.02aP < 0.05 vs. ischemia alone at 0 minutes.Ischemic030.2 ± 4.70.10 ± 0.01Ischemic/Indo603.1 ± 2.6aP < 0.05 vs. ischemia alone at 0 minutes.0.16 ± 0.01aP < 0.05 vs. ischemia alone at 0 minutes.Ischemic/PGE2602.8 ± 1.6aP < 0.05 vs. ischemia alone at 0 minutes.0.10 ± 0.02Ischemic/Indo/PGE2604.4 ± 1.6aP < 0.05 vs. ischemia alone at 0 minutes.0.14 ± 0.02aP < 0.05 vs. ischemia alone at 0 minutes.NOTE. Values represent means ± SE for % villus surface area denuded and villus height; n = 6. Tissues were subjected to 45 minutes ischemia in vivo. Tissues were harvested at 0 and 60 minutes after ischemia, fixed in 10% buffered formalin, and processed for histologic examination according to standard protocols. Indomethacin (Indo) was administered to select tissues at 5 × 10−6 mol/L, and PGE2 was given at 1 × 10−6 mol/L.a P < 0.05 vs. ischemia alone at 0 minutes. Open table in a new tab NOTE. Values represent means ± SE for % villus surface area denuded and villus height; n = 6. Tissues were subjected to 45 minutes ischemia in vivo. Tissues were harvested at 0 and 60 minutes after ischemia, fixed in 10% buffered formalin, and processed for histologic examination according to standard protocols. Indomethacin (Indo) was administered to select tissues at 5 × 10−6 mol/L, and PGE2 was given at 1 × 10−6 mol/L. Because basolateral Cl− uptake is mediated predominantly by the Na+-K+-2 Cl− cotransporter and represents a critical component of Cl− secretion, we treated tissues with the specific Na+-K+-2 Cl− transport inhibitor bumetanide, and measured its effect on Isc and TER. Application of bumetanide (10−4 mol/L) to the serosal side of is}, number={3}, journal={GASTROENTEROLOGY}, author={Moeser, AJ and Haskell, MM and Shifflett, DE and Little, D and Schultz, BD and Blikslager, AT}, year={2004}, month={Sep}, pages={802–815} }
 @article{little_flowers_hammerberg_gardner_2003, title={Management of drug-resistant cyathostominosis on a breeding farm in central North Carolina}, volume={35}, ISSN={["2042-3306"]}, DOI={10.2746/042516403776148264}, abstractNote={Summary Reasons for performing study : Possible anthelmintic resistance on a breeding farm where a rapid rotation anthelmintic programme had been implemented for 9 years was investigated. Cyathostomins resistant to fenbendazole and pyrantel were documented by faecal worm egg count reduction test (FWECRT). Objectives : To 1) manage small strongyle transmission in a herd of horses in which resistance to both pyrantel pamoate and fenbendazole was identified and thereby reduce the risk of clinical disease in the individual animal, 2) monitor the change in resistance patterns over time and 3) monitor the efficacy of ivermectin over the study period. Methods : Targeted ivermectin treatment of horses on the farm was instituted formature horses with faecal worm egg counts (FWEC) >200 eggs/g (epg) and for horses <age 2 years with FWEC >100 epg. Results : Over a 30 month period, targeted ivermectin treatment achieved acceptable control in mares, as judged by FWEC, and improved control of patent cyathostome infection in consecutive foal crops. Egg reappearance time (ERT) after treatment with ivermectin was <8 weeks in mares and foals more frequently in the second year of the study than in the first year. Numbers of anthelmintic treatments were reduced by 77.6 and 53.3% in the mare and foal group, respectively. Conclusions : Targeted ivermect in treatment may be an economically viable method of managing multiple drug resistant cyathostominosis. Potential relevance : Use of ivermectin should be monitored closely for development of resistance.}, number={3}, journal={EQUINE VETERINARY JOURNAL}, author={Little, D and Flowers, JR and Hammerberg, BH and Gardner, SY}, year={2003}, month={May}, pages={246–251} }
 @article{little_dean_young_mckane_martin_jones_blikslager_2003, title={PI3K signaling is required for prostaglandin-induced  mucosal recovery in ischemia-injured porcine ileum}, volume={284}, ISSN={0193-1857 1522-1547}, url={http://dx.doi.org/10.1152/ajpgi.00121.2002}, DOI={10.1152/ajpgi.00121.2002}, abstractNote={We have previously shown that PGE(2) and PGI(2) induce recovery of transepithelial resistance (TER) in ischemia-injured porcine ileal mucosa, associated with initial increases in Cl(-) secretion. We believe that the latter generates an osmotic gradient that stimulates resealing of tight junctions. Because of evidence implicating phosphatidylinositol 3-kinase (PI3K) in regulating tight junction assembly, we postulated that this signaling pathway is involved in PG-induced mucosal recovery. Porcine ileum was subjected to 45 min of ischemia, after which TER was monitored for a 180-min recovery period. Endogenous PG production was inhibited with indomethacin (5 microM). PGE(2) (1 microM) and PGI(2) (1 microM) stimulated recovery of TER, which was inhibited by serosal application of the osmotic agent urea (300 mosmol/kgH(2)O). The PI3K inhibitor wortmannin (10 nM) blocked recovery of TER in response to PGs or mucosal urea. Immunofluorescence imaging of recovering epithelium revealed that PGs restored occludin and zonula occludens-1 distribution to interepithelial junctions, and this pattern was disrupted by pretreatment with wortmannin. These experiments suggest that PGs stimulate recovery of paracellular resistance via a mechanism involving transepithelial osmotic gradients and PI3K-dependent restoration of tight junction protein distribution.}, number={1}, journal={American Journal of Physiology-Gastrointestinal and Liver Physiology}, publisher={American Physiological Society}, author={Little, Dianne and Dean, Rebecca A. and Young, Karen M. and McKane, Shaun A. and Martin, Linda D. and Jones, Samuel L. and Blikslager, Anthony T.}, year={2003}, month={Jan}, pages={G46–G56} }
 @article{stanar_little_redding_jones_2002, title={Equine rounds - Case presentation: Idiopathic eosinophilic enteritis in a 10-week-old colt}, volume={24}, number={4}, journal={Compendium on Continuing Education for the Practicing Veterinarian}, author={Stanar, L. S. and Little, D. and Redding, W. R. and Jones, S. L.}, year={2002}, pages={342–344} }
 @article{little_blikslager_2002, title={Factors associated with development of ileal impaction in horses with surgical colic: 78 cases (1986-2000)}, volume={34}, ISSN={["2042-3306"]}, DOI={10.2746/042516402776117773}, abstractNote={Deal impaction is prevalent in the south-eastern USA, where feeding of Coastal Bermuda hay has been implicated as a risk factor. Alternatively, infection with the tapeworm Anoplocephala perfoliata has been identified as a risk factor for ileal impaction in the UK. We hypothesised that feeding Coastal Bermuda hay and failure to administer routinely an anthelmintic with efficacy against tapeworms would place horses at risk of developing ileal impaction in the USA. Seventy-eight horses, with surgically confirmed ileal impaction and 100 horses admitted for colic that did not have an ileal impaction, were selected retrospectively for logistic regression analysis. Using odds ratios (OR) as an index of risk, feeding Coastal Bermuda hay (OR = 2.9) and failure to administer a pyrantel salt within 3 months of admission (OR = 3.1) placed horses at risk of development of ileal impaction. This study confirms the belief that feeding Coastal Bermuda hay places horses at risk of ileal impaction, although the quality of the hay may also play a role. Periodic administration of anthelmintics with efficacy against tapeworms should be considered to reduce risk of ileal impaction.}, number={5}, journal={EQUINE VETERINARY JOURNAL}, author={Little, D and Blikslager, AT}, year={2002}, month={Jul}, pages={464–468} }
 @article{little_keene_bruton_smith_powell_jones_2002, title={Percutaneous retrieval of a jugular catheter fragment from the pulmonary artery of a foal}, volume={220}, ISSN={["0003-1488"]}, url={http://europepmc.org/abstract/med/12126133}, DOI={10.2460/javma.2002.220.212}, abstractNote={A 49-kg (107.8-lb) sexually intact male Arabian foal was evaluated at 3 days of age because of profuse watery diarrhea, anorexia, and signs of abdominal pain. Physical examination findings were unremarkable except for evidence of diarrhea. A catheter was placed in the right jugular vein for administration of antimicrobials and lactated Ringer's solution. The foal was discharged with instructions to the owner to continue antimicrobial administration and fluid therapy; at home, the owner inadvertently cut the catheter at the level of the hub during attempted removal, and the catheter fragment migrated distally in the jugular vein and subsequently lodged in the pulmonary artery. The foal was readmitted to the hospital for retrieval of the fragment, using a percutaneous retrieval technique. Catheter fragmentation is a well-recognized risk of catheterization in horses. Catheter fragments can be retrieved somewhat easily from the jugular vein; however, if the fragment migrates to the heart or pulmonary artery, imaging the fragment to locate and retrieve it can be difficult. Complications associated with catheter fragmentation include septicemia, endocarditis, lung abscesses, pulmonary embolism, dysrhythmias, cardiac perforation, pulmonary or caval thrombosis, and death. To our knowledge, this is the first report of successful retrieval of a catheter fragment from the pulmonary artery in a horse.}, number={2}, journal={JOURNAL OF THE AMERICAN VETERINARY MEDICAL ASSOCIATION}, author={Little, D and Keene, BW and Bruton, C and Smith, LJ and Powell, S and Jones, SL}, year={2002}, month={Jan}, pages={212–214} }
 @article{blikslager_zimmel_young_campbell_little_argenzio_2002, title={Recovery of ischaemic injured porcine ileum: evidence for a contributory role of COX-1 and COX-2}, volume={50}, ISSN={0017-5749}, url={http://dx.doi.org/10.1136/gut.50.5.615}, DOI={10.1136/gut.50.5.615}, abstractNote={Background: We have previously shown that the non-selective cyclooxygenase (COX) inhibitor indomethacin retards recovery of intestinal barrier function in ischaemic injured porcine ileum. However, the relative role of COX-1 and COX-2 elaborated prostaglandins in this process is unclear. Aims: To assess the role of COX-1 and COX-2 elaborated prostaglandins in the recovery of intestinal barrier function by evaluating the effects of selective COX-1 and COX-2 inhibitors on mucosal recovery and eicosanoid production. Methods: Porcine ileal mucosa subjected to 45 minutes of ischaemia was mounted in Ussing chambers, and transepithelial electrical resistance was used as an indicator of mucosal recovery. Prostaglandins E<sub>1</sub> and E<sub>2</sub> (PGE) and 6-keto-PGF<sub>1α</sub> (the stable metabolite of prostaglandin I<sub>2</sub> (PGI<sub>2</sub>)) were measured using ELISA. Thromboxane B<sub>2</sub> (TXB<sub>2</sub>, the stable metabolite of TXA<sub>2</sub>) was measured as a likely indicator of COX-1 activity. Results: Ischaemic injured tissues recovered to control levels of resistance within three hours whereas tissues treated with indomethacin (5×10<sup>−6</sup> M) failed to fully recover, associated with inhibition of eicosanoid production. Injured tissues treated with the selective COX-1 inhibitor SC-560 (5×10<sup>−6</sup> M) or the COX-2 inhibitor NS-398 (5×10<sup>−6</sup> M) recovered to control levels of resistance within three hours, associated with significant elevations of PGE and 6-keto-PGF<sub>1α</sub> compared with untreated tissues. However, SC-560 significantly inhibited TXB<sub>2</sub> production whereas NS-398 had no effect on this eicosanoid, indicating differential actions of these inhibitors related to their COX selectivity. Conclusions: The results suggest that recovery of resistance is triggered by PGE and PGI<sub>2</sub>, which may be elaborated by either COX-1 or COX-2.}, number={5}, journal={Gut}, publisher={BMJ}, author={Blikslager, A.T. and Zimmel, D.N. and Young, K.M. and Campbell, N.B. and Little, D. and Argenzio, R.A.}, year={2002}, month={May}, pages={615–623} }
 @article{little_redding_blikslager_2001, title={Risk factors for reduced postoperative fecal output in horses: 37 cases (1997-1998)}, volume={218}, ISSN={["0003-1488"]}, DOI={10.2460/javma.2001.218.414}, abstractNote={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).Retrospective study.37 horses that developed RPFO after undergoing general anesthesia for reasons unrelated to the gastrointestinal tract.Fecal output was obtained from medical records as number of defecations per 24-hour period after surgery; RPFO was defined as < or = 3 defecations per 24-hour period after surgery. The reference population included 48 horses that defecated > or = 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.Ten (12%) horses, all of which had RPFO, developed signs of colic after surgery. Horses > or = 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.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.}, number={3}, journal={JOURNAL OF THE AMERICAN VETERINARY MEDICAL ASSOCIATION}, author={Little, D and Redding, WR and Blikslager, AT}, year={2001}, month={Feb}, pages={414–420} }
 @article{little_redding_spaulding_dupree_jones_2000, title={Unusual presentation of nutritional secondary hyperparathyroidism in a Paint colt}, volume={2}, DOI={10.1111/j.2042-3292.2000.tb00064.x}, abstractNote={Equine Veterinary EducationVolume 12, Issue 6 p. 297-302 Unusual presentation of nutritional secondary hyperparathyroidism in a Paint colt D. Little, Department of Clinical Sciences, College of Veterinary Medicine, North Carolina State University, 4700 Hillsborough Street, Raleigh, North Carolina 27606, USA.Search for more papers by this authorW. R. Redding, Department of Clinical Sciences, College of Veterinary Medicine, North Carolina State University, 4700 Hillsborough Street, Raleigh, North Carolina 27606, USA.Search for more papers by this authorK. A. Spaulding, Anatomy, Physiology and Radiology, College of Veterinary Medicine, North Carolina State University, 4700 Hillsborough Street, Raleigh, North Carolina 27606, USA.Search for more papers by this authorS. H. Dupree, Veterinary Teaching Hospital, College of Veterinary Medicine, North Carolina State University, 4700 Hillsborough Street, Raleigh, North Carolina 27606, USA.Search for more papers by this authorS. L. Jones, Department of Clinical Sciences, College of Veterinary Medicine, North Carolina State University, 4700 Hillsborough Street, Raleigh, North Carolina 27606, USA.Search for more papers by this author D. Little, Department of Clinical Sciences, College of Veterinary Medicine, North Carolina State University, 4700 Hillsborough Street, Raleigh, North Carolina 27606, USA.Search for more papers by this authorW. R. Redding, Department of Clinical Sciences, College of Veterinary Medicine, North Carolina State University, 4700 Hillsborough Street, Raleigh, North Carolina 27606, USA.Search for more papers by this authorK. A. Spaulding, Anatomy, Physiology and Radiology, College of Veterinary Medicine, North Carolina State University, 4700 Hillsborough Street, Raleigh, North Carolina 27606, USA.Search for more papers by this authorS. H. Dupree, Veterinary Teaching Hospital, College of Veterinary Medicine, North Carolina State University, 4700 Hillsborough Street, Raleigh, North Carolina 27606, USA.Search for more papers by this authorS. L. Jones, Department of Clinical Sciences, College of Veterinary Medicine, North Carolina State University, 4700 Hillsborough Street, Raleigh, North Carolina 27606, USA.Search for more papers by this author First published: 05 January 2010 https://doi.org/10.1111/j.2042-3292.2000.tb00064.xCitations: 3AboutPDF ToolsExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onEmailFacebookTwitterLinked InRedditWechat Citing Literature Volume12, Issue6December 2000Pages 297-302 RelatedInformation}, number={6}, journal={Equine Veterinary Education}, author={Little, D. and Redding, W.R. and Spaulding, K.A. and Dupree, S.H. and Jones, S.L.}, year={2000}, pages={388–394} }