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Verhaar N, Grages AM, Bienert-Zeit A, Schwieder A, Reineking W, Hewicker-Trautwein M, Kästner S, Geburek F. Flowmetry and spectrophotometry for the assessment of intestinal viability in horses with naturally occurring strangulating small intestinal lesions. Equine Vet J 2024. [PMID: 38888520 DOI: 10.1111/evj.14118] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2023] [Accepted: 05/16/2024] [Indexed: 06/20/2024]
Abstract
BACKGROUND Ancillary diagnostic methods to enhance the accuracy of viability assessment have not been established for use in clinical practice. OBJECTIVES To assess intestinal microperfusion measured by Laser Doppler Flowmetry and Spectrophotometry (LDFS) in naturally occurring small intestinal strangulations of different origins and to compare this between viable and non-viable segments. STUDY DESIGN Prospective clinical trial. METHODS Forty horses undergoing colic surgery for naturally occurring small intestinal strangulations were included. Tissue oxygen saturation (tSO2), haemoglobin (tHB) and blood flow (tBF) were determined by LDFS before and after release of the strangulation. Intestinal biopsies were taken in cases that underwent intestinal resection or intraoperative euthanasia and assessed using a semi-quantitative mucosal injury score (MIS). The LDFS measurements were compared between the different categories of strangulation causes and histopathological injury using parametric and non-parametric tests (p < 0.05). RESULTS Strangulations by pedunculated lipomas had lower tBF (13.9 ± 18 arbitrary units [AU]) than epiploic foramen entrapments (65.2 ± 61 AU; CI -1.697 to -0.2498; p = 0.005). Segments with MIS > 5 showed lower tBF during strangulation than segments with MIS < 4 (mean difference 61.1 AU; CI -1.119 to -0.07361; p = 0.03). This did not differ significantly following release of strangulation. Furthermore, there was a positive correlation between the inflammatory cell count and tBF during strangulation (r 0.34; CI 0.01 to 0.60; p = 0.04). The tSO2 and tHB did not differ between the different categories of lesions or injury. MAIN LIMITATIONS No biopsies could be taken from the intestinal segments that did not undergo resection. The duration of strangulation could not reliably be ascertained. CONCLUSIONS Blood flow measurements in naturally occurring strangulating lesions show a varying degree of ischaemia in different causes of strangulation. Intestinal blood flow measurements prior to release of the strangulation could potentially contribute to the identification of mucosal injury, yet a high individual variability and other contributing factors need to be considered.
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Affiliation(s)
- Nicole Verhaar
- Clinic for Horses, University of Veterinary Medicine Hannover, Hannover, Germany
| | - Anna Marei Grages
- Clinic for Horses, University of Veterinary Medicine Hannover, Hannover, Germany
| | - Astrid Bienert-Zeit
- Clinic for Horses, University of Veterinary Medicine Hannover, Hannover, Germany
| | - Alexander Schwieder
- Clinic for Horses, University of Veterinary Medicine Hannover, Hannover, Germany
| | - Wencke Reineking
- Department of Pathology, University of Veterinary Medicine Hannover, Hannover, Germany
| | | | - Sabine Kästner
- Clinic for Horses, University of Veterinary Medicine Hannover, Hannover, Germany
- Clinic for Small Animals, University of Veterinary Medicine Hannover, Hannover, Germany
| | - Florian Geburek
- Clinic for Horses, University of Veterinary Medicine Hannover, Hannover, Germany
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Ruíz-López P, Cuypers C, Schauvliege S. Xylazine Infusion during Equine Colic Anesthesia with Isoflurane and Lidocaine: A Retrospective Study. Animals (Basel) 2023; 13:2902. [PMID: 37760302 PMCID: PMC10525755 DOI: 10.3390/ani13182902] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2023] [Revised: 09/08/2023] [Accepted: 09/11/2023] [Indexed: 09/29/2023] Open
Abstract
This retrospective study investigated the effect of a xylazine infusion on heart rate; mean arterial pressure; blood gases; anesthetic and dobutamine requirements; recovery quality and duration; percentage of death/survival; and days to die/discharge in horses after colic surgery under partial intravenous anesthesia with isoflurane and lidocaine infusion. Anesthetic records of equine colic surgery were reviewed from similar periods in 2020-2021 and 2021-2022. In both groups, after sedation with xylazine 0.7 mg/kg intravenously (IV) and induction with ketamine 2.2 mg/kg and midazolam 0.06 mg/kg IV, anesthesia was maintained with isoflurane and lidocaine (bolus 1.5 mg/kg IV, infusion 2 mg/kg/h). Group L (2020-2021, n = 45) received xylazine 0.2 mg/kg IV before recovery, group XL (2021-2022, n = 44) received xylazine 0.5 mg/kg/h IV intraoperatively. In group XL, minimal (p = 0.04) and average (p = 0.04) heart rate, intraoperative hematocrit (p = 0.001), minimal (p = 0.002) and maximal (p = 0.04) dobutamine administration rate, animals requiring ketamine top-ups (p = 0.04), and the number of days to discharge (p = 0.02), were significantly lower compared to group L. During recovery in group XL, the time to sternal recumbency (p = 0.03) and time to first attempt (p = 0.04) were significantly longer. This retrospective study suggests that a xylazine infusion may have beneficial effects on horses undergoing colic surgery. Further prospective studies are necessary.
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Affiliation(s)
- Patricia Ruíz-López
- Department of Large Animal Surgery, Anesthesia and Orthopedics, Faculty of Veterinary Medicine, University of Ghent, 9820 Merelbeke, Belgium;
| | | | - Stijn Schauvliege
- Department of Large Animal Surgery, Anesthesia and Orthopedics, Faculty of Veterinary Medicine, University of Ghent, 9820 Merelbeke, Belgium;
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Verhaar N, Kopp V, Pfarrer C, Neudeck S, König K, Rohn K, Kästner S. Alpha 2 Antagonist Vatinoxan Does Not Abolish the Preconditioning Effect of Dexmedetomidine on Experimental Ischaemia-Reperfusion Injury in the Equine Small Intestine. Animals (Basel) 2023; 13:2755. [PMID: 37685019 PMCID: PMC10486550 DOI: 10.3390/ani13172755] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2023] [Revised: 08/25/2023] [Accepted: 08/28/2023] [Indexed: 09/10/2023] Open
Abstract
Pharmacological preconditioning with dexmedetomidine has been shown to ameliorate intestinal ischaemia reperfusion injury in different species, including horses. However, it remains unknown if this effect is related to alpha2 adrenoreceptor activity. Therefore, the aim of this study was to determine the effect of dexmedetomidine preconditioning with and without the administration of the peripheral alpha2 antagonist vatinoxan. This prospective randomized experimental trial included 12 horses equally divided between two treatment groups. Horses in group Dex received a bolus of dexmedetomidine followed by a continuous rate infusion (CRI), while group DexV additionally received vatinoxan as bolus and CRI. A median laparotomy was performed under general anaesthesia, and jejunal ischaemia was applied for 90 min, followed by 30 min of reperfusion. Mucosal damage was evaluated in full thickness biopsies by use of a semiquantitative mucosal injury score and by determining the apoptotic cell counts with immunohistochemical staining for cleaved caspase-3 and TUNEL. Comparisons between the groups and time points were performed using non-parametric tests (p < 0.05). During pre-ischaemia and ischaemia, no differences could be found in mucosal injury between the groups. After reperfusion, group DexV showed lower mucosal injury scores compared to group Dex. The apoptotic cell counts did not differ between the groups. In conclusion, antagonizing the peripheral alpha2 adrenoreceptors did not negatively affect dexmedetomidine preconditioning.
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Affiliation(s)
- Nicole Verhaar
- Clinic for Horses, University of Veterinary Medicine Hannover, 30559 Hannover, Germany
| | - Veronika Kopp
- Clinic for Horses, University of Veterinary Medicine Hannover, 30559 Hannover, Germany
| | - Christiane Pfarrer
- Institute for Anatomy, University of Veterinary Medicine Hannover, 30559 Hannover, Germany
| | - Stephan Neudeck
- Small Animal Clinic, University of Veterinary Medicine Hannover, 30559 Hannover, Germany
| | - Kathrin König
- Clinic for Horses, University of Veterinary Medicine Hannover, 30559 Hannover, Germany
| | - Karl Rohn
- Department of Biometry, University of Veterinary Medicine Hannover, 30559 Hannover, Germany
| | - Sabine Kästner
- Clinic for Horses, University of Veterinary Medicine Hannover, 30559 Hannover, Germany
- Small Animal Clinic, University of Veterinary Medicine Hannover, 30559 Hannover, Germany
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Dengler F, Sternberg F, Grages M, Kästner SBR, Verhaar N. Adaptive mechanisms in no flow vs. low flow ischemia in equine jejunum epithelium: Different paths to the same destination. Front Vet Sci 2022; 9:947482. [PMID: 36157182 PMCID: PMC9493374 DOI: 10.3389/fvets.2022.947482] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2022] [Accepted: 08/17/2022] [Indexed: 01/18/2023] Open
Abstract
Intestinal ischemia reperfusion injury (IRI) is a frequent complication of equine colic. Several mechanisms may be involved in adaptation of the intestinal epithelium to IRI and might infer therapeutic potential, including hypoxia-inducible factor (HIF) 1α, AMP-activated protein kinase (AMPK), nuclear factor-erythroid 2-related factor 2 (NRF2), and induction of autophagy. However, the mechanisms supporting adaptation and thus cellular survival are not completely understood yet. We investigated the activation of specific adaptation mechanisms in both no and low flow ischemia and reperfusion simulated in equine jejunum epithelium in vivo. We found an activation of HIF1α in no and low flow ischemia as indicated by increased levels of HIF1α target genes and phosphorylation of AMPKα tended to increase during ischemia. Furthermore, the protein expression of the autophagy marker LC3B in combination with decreased expression of nuclear-encoded mitochondrial genes indicates an increased rate of mitophagy in equine intestinal IRI, possibly preventing damage by mitochondria-derived reactive oxygen species (ROS). Interestingly, ROS levels were increased only shortly after the onset of low flow ischemia, which may be explained by an increased antioxidative defense, although NFR2 was not activated in this setup. In conclusion, we could demonstrate that a variety of adaptation mechanisms manipulating different aspects of cellular homeostasis are activated in IRI irrespective of the ischemia model, and that mitophagy might be an important factor for epithelial survival following small intestinal ischemia in horses that should be investigated further.
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Affiliation(s)
- Franziska Dengler
- Department of Biochemical Sciences, Institute of Physiology, Pathophysiology and Biophysics, University of Veterinary Medicine, Vienna, Austria
- *Correspondence: Franziska Dengler
| | - Felix Sternberg
- Department of Biochemical Sciences, Institute of Physiology, Pathophysiology and Biophysics, University of Veterinary Medicine, Vienna, Austria
| | - Marei Grages
- Clinic for Horses, University of Veterinary Medicine Hannover, Hannover, Germany
| | - Sabine BR Kästner
- Clinic for Horses, University of Veterinary Medicine Hannover, Hannover, Germany
- Small Animal Clinic, University of Veterinary Medicine Hannover, Hannover, Germany
| | - Nicole Verhaar
- Clinic for Horses, University of Veterinary Medicine Hannover, Hannover, Germany
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Low Flow versus No Flow: Ischaemia Reperfusion Injury Following Different Experimental Models in the Equine Small Intestine. Animals (Basel) 2022; 12:ani12162158. [PMID: 36009747 PMCID: PMC9405230 DOI: 10.3390/ani12162158] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2022] [Revised: 08/17/2022] [Accepted: 08/19/2022] [Indexed: 11/17/2022] Open
Abstract
Simple Summary One of the main causes of colic in horses is the occlusion of the intestinal blood vessels after displacement or entrapment of the small intestine. In search of new therapies to treat this lethal disease, experimental models have been used to simulate the clinical situation. Both low flow (LF) models with partial blood flow occlusion as well as no flow (NF) models with complete occlusion have been implemented in different studies. This has led to conflicting results and comparative studies are lacking. The objective of this study was to characterize the development of intestinal injury over time in two different experimental models implementing either partial or complete vessel occlusion. Under general anaesthesia, local intestinal blood flow was reduced by 80% in seven horses (LF), and by 100% in another seven horses (NF). The LF group exhibited more bleeding in the intestinal wall and a relatively high variability in intestinal oxygen levels and tissue damage. The NF group showed lower oxygen levels and decreased barrier function of the intestinal wall. These results aid in the selection of the suitable experimental model for future studies. The high variability following LF suggests that an NF model may produce more consistent intestinal damage. Abstract In experimental studies investigating strangulating intestinal lesions in horses, different ischaemia models have been used with diverging results. Therefore, the aim was to comparatively describe ischaemia reperfusion injury (IRI) in a low flow (LF) and no flow (NF) model. Under general anaesthesia, 120 min of jejunal ischaemia followed by 120 min of reperfusion was induced in 14 warmbloods. During ischaemia, blood flow was reduced by 80% (LF, n = 7) or by 100% (NF, n = 7). Intestinal blood flow and oxygen saturation were measured by Laser Doppler fluxmetry and spectrophotometry. Clinical, histological, immunohistochemical and Ussing chamber analyses were performed on intestinal samples collected hourly. Tissue oxygen saturation was significantly lower in NF ischaemia. The LF group exhibited high variability in oxygen saturation and mucosal damage. Histologically, more haemorrhage was found in the LF group at all time points. Cleaved-caspase-3 and calprotectin-stained cells increased during reperfusion in both groups. After NF ischaemia, the tissue conductance was significantly higher during reperfusion. These results aid in the selection of suitable experimental models for future studies. Although the LF model has been suggested to be more representative for clinical strangulating small intestinal disease, the NF model produced more consistent IRI.
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Sengul I, Sengul D. Clinical Insights on Pre- and Novel Postconditioning in Equine Jejunal Ischemia. Med Arch 2021; 75:237-238. [PMID: 34483457 PMCID: PMC8385745 DOI: 10.5455/medarh.2021.75.237-238] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2021] [Accepted: 06/30/2021] [Indexed: 11/25/2022] Open
Affiliation(s)
- Ilker Sengul
- Division of Endocrine Surgery, Giresun University Faculty of Medicine, Giresun, Turkey.,Department of General Surgery, Giresun University Faculty of Medicine, Giresun, Turkey
| | - Demet Sengul
- Department of Pathology, Giresun University, Faculty of Medicine, Giresun, Turkey
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Verhaar N, de Buhr N, von Köckritz-Blickwede M, Hewicker-Trautwein M, Pfarrer C, Mazzuoli-Weber G, Schulte H, Kästner S. Ischaemic postconditioning reduces apoptosis in experimental jejunal ischaemia in horses. BMC Vet Res 2021; 17:175. [PMID: 33902575 PMCID: PMC8077964 DOI: 10.1186/s12917-021-02877-y] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2021] [Accepted: 04/12/2021] [Indexed: 03/06/2023] Open
Abstract
BACKGROUND Ischaemic postconditioning (IPoC) refers to brief periods of reocclusion of blood supply following an ischaemic event. This has been shown to ameliorate ischaemia reperfusion injury in different tissues, and it may represent a feasible therapeutic strategy for ischaemia reperfusion injury following strangulating small intestinal lesions in horses. The objective of this study was to assess the degree cell death, inflammation, oxidative stress, and heat shock response in an equine experimental jejunal ischaemia model with and without IPoC. METHODS In this randomized, controlled, experimental in vivo study, 14 horses were evenly assigned to a control group and a group subjected to IPoC. Under general anaesthesia, segmental ischaemia with arterial and venous occlusion was induced in 1.5 m jejunum. Following ischaemia, the mesenteric vessels were repeatedly re-occluded in group IPoC only. Full thickness intestinal samples and blood samples were taken at the end of the pre-ischaemia period, after ischaemia, and after 120 min of reperfusion. Immunohistochemical staining or enzymatic assays were performed to determine the selected variables. RESULTS The mucosal cleaved-caspase-3 and TUNEL cell counts were significantly increased after reperfusion in the control group only. The cleaved-caspase-3 cell count was significantly lower in group IPoC after reperfusion compared to the control group. After reperfusion, the tissue myeloperoxidase activity and the calprotectin positive cell counts in the mucosa were increased in both groups, and only group IPoC showed a significant increase in the serosa. Tissue malondialdehyde and superoxide dismutase as well as blood lactate levels showed significant progression during ischaemia or reperfusion. The nuclear immunoreactivity of Heat shock protein-70 increased significantly during reperfusion. None of these variables differed between the groups. The neuronal cell counts in the myenteric plexus ganglia were not affected by the ischaemia model. CONCLUSIONS A reduced apoptotic cell count was found in the group subjected to IPoC. None of the other tested variables were significantly affected by IPoC. Therefore, the clinical relevance and possible protective mechanism of IPoC in equine intestinal ischaemia remains unclear. Further research on the mechanism of action and its effect in clinical cases of strangulating colic is needed.
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Affiliation(s)
- Nicole Verhaar
- Clinic for Horses, University of Veterinary Medicine Hannover, Hannover, Germany.
| | - Nicole de Buhr
- Department of Biochemistry, University of Veterinary Medicine Hannover, Hannover, Germany
- Research Center for Emerging Infections and Zoonoses, University of Veterinary Medicine Hannover, Hannover, Germany
| | - Maren von Köckritz-Blickwede
- Department of Biochemistry, University of Veterinary Medicine Hannover, Hannover, Germany
- Research Center for Emerging Infections and Zoonoses, University of Veterinary Medicine Hannover, Hannover, Germany
| | | | - Christiane Pfarrer
- Institute for Anatomy, University of Veterinary Medicine Hannover, Hannover, Germany
| | - Gemma Mazzuoli-Weber
- Institute for Physiology and Cell Biology, University of Veterinary Medicine Hannover, Hannover, Germany
| | - Henri Schulte
- Institute of Functional and Applied Anatomy, Hannover Medical School, Hannover, Germany
| | - Sabine Kästner
- Clinic for Horses, University of Veterinary Medicine Hannover, Hannover, Germany
- Small Animal Clinic, University of Veterinary Medicine Hannover, Hannover, Germany
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8
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Sengul I, Sengul D, Pelikán A. Interpretations on Preconditioning with Lidocaine and Xylazine in Experimental Equine Jejunal Ischaemia. Med Arch 2020; 74:323-324. [PMID: 33041455 PMCID: PMC7520056 DOI: 10.5455/medarh.2020.74.323-324] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Affiliation(s)
- Ilker Sengul
- Division of Endocrine Surgery, Giresun University Faculty of Medicine, Giresun, Turkey.,Department of General Surgery, Giresun University Faculty of Medicine, Giresun, Turkey
| | - Demet Sengul
- Department of Pathology, Giresun University Faculty of Medicine, Giresun, Turkey
| | - Anton Pelikán
- Department of Health Care Sciences, Faculty of Humanities, Univerzita Tomáše Bati ve Zlíně, Zlín, Czech Republic.,Department of General Surgery, Faculty of Medicine, Ostravska Univerzita V Ostrave, Ostrava, Czech Republic
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VanderBroek AR, Engiles JB, Kästner SBR, Kopp V, Verhaar N, Hopster K. Protective effects of dexmedetomidine on small intestinal ischaemia-reperfusion injury in horses. Equine Vet J 2020; 53:569-578. [PMID: 32862437 DOI: 10.1111/evj.13337] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2020] [Revised: 07/06/2020] [Accepted: 08/13/2020] [Indexed: 12/26/2022]
Abstract
BACKGROUND Strangulating small intestinal lesions in the horse have increased morbidity and mortality compared to nonstrangulating obstructions due to mucosal barrier disruption and subsequent endotoxaemia. OBJECTIVES To investigate protective effects of dexmedetomidine on small intestinal ischaemia-reperfusion injury in the horse. STUDY DESIGN Randomised, controlled, experimental study. METHODS Eighteen systemically healthy horses were randomly assigned to three groups: control, preconditioning, and post-conditioning. During isoflurane anaesthesia, complete ischaemia was induced in a 1-m segment of jejunum for 90 minutes. Horses in the preconditioning and post-conditioning groups received dexmedetomidine (3.5 µg/kg followed by 7 µg/kg/h) before (preconditioning) or after beginning ischaemia (post-conditioning), and during reperfusion. Jejunal biopsies were collected before ischaemia (baseline-1), at the end of the ischaemic period (ischaemia), and 30 minutes after reperfusion (reperfusion-1). Additional biopsies were taken 24 hours after reperfusion from ischaemia-reperfusion-injured jejunum (reperfusion-2). Epithelial injury was scored histologically, and morphometric analyses were used to calculate villus surface area (VSA) denuded of epithelium. Data were analysed using analysis of variance, Kruskal-Wallis and Wilcoxon two-sample tests. RESULTS In the control group, epithelial injury scores and percentage of VSA denudation for ischaemia-reperfusion-injured jejunum were higher compared to baseline-1 at all time points. The ischaemia and both reperfusion samples from the pre- and post-conditioning groups had lower epithelial injury scores and percentage of VSA epithelial denudation compared to the control group, with no difference from baseline-1 at any time point for the preconditioning group. MAIN LIMITATIONS Preconditioning has limited application in the clinical setting with naturally occurring strangulating small intestinal lesions. CONCLUSIONS Dexmedetomidine was protective for small intestinal ischaemia-reperfusion injury in the horse when administered before or during ischaemia.
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Affiliation(s)
- Ashley R VanderBroek
- Department of Large Animal Clinical Sciences, College of Veterinary Medicine, Michigan State University, East Lansing, MI, USA
| | - Julie B Engiles
- Department of Pathobiology, School of Veterinary Medicine, University of Pennsylvania, Kennett Square, PA, USA
| | - Sabine B R Kästner
- Clinic for Horses, University of Veterinary Medicine Hannover, Foundation, Hannover, Germany
| | - Veronika Kopp
- Clinic for Horses, University of Veterinary Medicine Hannover, Foundation, Hannover, Germany
| | - Nicole Verhaar
- Clinic for Horses, University of Veterinary Medicine Hannover, Foundation, Hannover, Germany
| | - Klaus Hopster
- Department of Clinical Studies, School of Veterinary Medicine, University of Pennsylvania, Kennett Square, PA, USA
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