OBJECTIVE To compare intraluminal pressure at initial leakage (leakage pressure), leakage location, and maximum intraluminal pressure (MIP) for various staple line offset configurations of functional end-to-end stapled anastomosis (FEESA). SAMPLE Grossly normal jejunal segments from 4 canine cadavers. PROCEDURES 52 jejunal segments (4 control and 24 anastomosis constructs [2 segments/standard FEESA construct]) were prepared for testing. Segments were assigned to three 8-segment gastrointestinal anastomosis staple line offset groups: complete offset (CSO group), partial gastrointestinal anastomosis offset (PSO group), and no gastrointestinal anastomosis offset (NSO group). Results for leakage pressure, leakage location, and MIP were compared. RESULTS Mean ± SD leakage pressure differed significantly among all groups and was highest for the PSO group (34.4 ± 3.7 mm Hg), followed by the CSO group (25.9 ± 4.1 mm Hg) and the NSO group (18.8 ± 1.5 mm Hg). Leakage location did not differ significantly among groups but was most commonly associated with the thoracoabdominal staple line. The MIP did not differ significantly among groups (PSO, 83.1 ± 9.4 mm Hg; CSO, 81.7 ± 6.7 mm Hg; and NSO, 58.5 ± 7.7 mm Hg). CONCLUSIONS AND CLINICAL RELEVANCE In this study, partial staple line offset leaked at a significantly higher pressure, which represented the greatest leakage protection of tested constructs. The thoracoabdominal staple line was more susceptible to leakage than was the gastrointestinal anastomosis staple line. Results suggested that surgeons should avoid FEESA with no staple line offset, strive for partial offset of the gastrointestinal anastomosis staples, and provide precise placement of the thoracoabdominal staple line.

OBJECTIVE To characterize epithelial cells of the small intestine and colon in horses without clinical gastrointestinal abnormalities with an emphasis on the stem cell niche constituents. SAMPLE Mucosal biopsy specimens from small and large intestines obtained from 12 horses euthanized for reasons unrelated to gastrointestinal disease or systemic disease. PROCEDURES Intestinal biopsy specimens were collected by sharp dissection immediately following euthanasia. Specimens were prepared for immunohistochemical, immunofluorescence, and transmission electron microscopic imaging to detect and characterize each epithelial cell type. Antibodies against protein biomarkers for cellular identification were selected on the basis of expression in other mammalian species. RESULTS Intestinal epithelial cell types were identified by means of immunostaining and morphological characterization with transmission electron microscopy. Some differences in biomarker expression and antibody cross-reactivity were identified in equine tissue, compared with other species. However, each known type of mucosal epithelial cell was identified in equine tissue. CONCLUSIONS AND CLINICAL RELEVANCE The methodology used can enhance detection of stem cells and progenitor cells as well as postmitotic cell lineages in equine intestinal tissues. Results may have relevance to regenerative potential of intestinal mucosa and survival in horses with colic.

OBJECTIVE To determine the effect of dantrolene premedication on various cardiovascular and biochemical variables and recovery in isoflurane-anesthetized horses. ANIMALS 6 healthy horses. PROCEDURES Each horse was anesthetized twice with a 21- to 28-day washout period between anesthetic sessions. Food was not withheld from horses before either session. During each session, dantrolene (6 mg/kg in 2 L of water) or water (2 L) was administered via a nasogastric tube 1 hour before anesthesia was induced. Anesthesia was maintained with isoflurane for 90 minutes, during which blood gas analyses and lithium-dilution cardiac output (CO) measurements were obtained every 10 minutes. Serum creatine kinase activity was measured before and at 4, 8, and 12 hours after anesthesia. RESULTS When horses were premedicated with dantrolene, CO at 25, 35, and 45 minutes after induction of anesthesia was significantly lower than that when horses were premedicated with water after which time difficulty in obtaining valid measurements suggested a continued decrease in CO; plasma potassium concentration progressively increased during anesthesia, whereas serum creatine kinase activity remained fairly stable and within reference limits through 12 hours after anesthesia; and 2 of 6 horses developed cardiac arrhythmias that required medical intervention. The quality of anesthetic recovery was slightly better when horses were premedicated with dantrolene versus water, although the time required for recovery did not differ significantly between treatments. CONCLUSIONS AND CLINICAL RELEVANCE Results suggested that dantrolene premedication prevented muscle damage without affecting anesthetic recovery but impaired CO and precipitated hyperkalemia and cardiac arrhythmias in healthy isoflurane-anesthetized horses.

This study describes and measures the impact of different compositions and finishes of stainless steel used in equipment in the meat industry on the transfer of natural flora and selected pathogens from artificially contaminated pork skin. It is known that the adhesion to surfaces of Listeria monocytogenes and Salmonella, 2 pathogens frequently found in contaminated pork meat, depends on the nature and roughness of the surface. Our results show no statistically significant differences in microbial transfer regardless of the types of stainless steel considered, with the highest measured transfer difference being 0.18 log colony-forming units (CFUs)/800 cm2. Moreover, no differences in total microbial community were observed after transfer on the 5 types of stainless steel using single-strand conformation polymorphism (SSCP). It was concluded that the different characteristics of the stainless steel tested did not affect the initial bacterial transfer in this study.

OBJECTIVE To evaluate ex vivo cyclooxygenase (COX) inhibition and compare in vitro and ex vivo COX-1 inhibition by flunixin meglumine and firocoxib in horses. ANIMALS 4 healthy horses for in vitro experiments and 12 healthy horses (6 males and 6 females; 5 Thoroughbreds, 5 Warmbloods, and 2 ponies) undergoing elective surgery for ex vivo experiments. PROCEDURES 12 horses received flunixin meglumine (1.1 mg/kg, IV, q 12 h) or firocoxib (0.09 mg/kg, IV, q 24 h). Blood samples were collected before (baseline) and 2 and 24 hours after NSAID administration. Prostanoids (thromboxane B2, prostaglandin E2, and prostaglandin E metabolites) served as indicators of COX activity, and serum drug concentrations were measured by use of high-performance liquid chromatography. An in vitro coagulation-induced thromboxane B2 assay was used to calculate drug concentration-COX-1 inhibition curves. Effect of time and treatment on COX activity was determined. Agreement between in vitro and ex vivo measurement of COX activity was assessed with Bland-Altman analysis. RESULTS At 2 and 24 hours after NSAID administration, COX-1 activity was reduced, compared with baseline activity, for the flunixin meglumine group only and relative COX-1 activity was significantly greater for the firocoxib group, compared with that for the flunixin meglumine group. There was no significant change in COX-2 activity after surgery for either group. Bland-Altman analysis revealed poor agreement between in vitro and ex vivo measurement of COX-1 activity. CONCLUSIONS AND CLINICAL RELEVANCE Compared with flunixin meglumine, firocoxib had COX-1-sparing effects ex vivo in equine patients that underwent elective surgery.

Circulating monocytes and tissue macrophages were suggested to be susceptible to avian reovirus (ARV) infection. To determine if ARV infects and replicates in mononuclear phagocytes (KUL01-positive cells), we infected 3-day-old specific-pathogen-free chickens with ARV strain 2408 by inoculation of the left footpad. The left footpads and spleens were collected for analysis at 1.5 and 2.5 d after inoculation. Replication of ARV in the footpad and spleen was demonstrated by detection of the viral protein σNS using immunohistochemical testing and viral S1 RNA expression by real-time quantitative polymerase chain reaction (qPCR). Furthermore, immunofluorescent double-staining assay of cytocentrifuged cells and cryosections of the footpad and spleen for the viral protein σNS and the surface marker recognized by monoclonal antibody (MAb) KUL01 indicated that KUL01-positive cells costained with MAb H1E1, which recognizes ARV protein σNS. In addition, more ARV S1 RNA was measured by qPCR in the KUL01-positive cell samples prepared from the footpad or spleen 1.5 d after inoculation compared with non-KUL01-positive cell samples. The amounts of ARV S1 RNA in the spleen were significantly lower (P < 0.05) than the amounts in the footpad 1.5 d after inoculation. The results suggest that ARV infects mononuclear phagocytes and then replicates within these cells before migrating to the spleen, where it infects and replicates in KUL01-positive cells.

OBJECTIVE To evaluate species differences and effects of storage duration and temperature on the anticollagenase efficacy of canine, feline, and equine serum on in vitro corneal degradation. SAMPLES Corneas and serum from dogs, cats, and horses. PROCEDURES Clinically normal corneas from dogs, cats, and horses were harvested within 2 hours after euthanasia. Serum samples from dogs, cats, and horses were collected and pooled by species. Corneal specimens were incubated with collagenase derived from Clostridium histolyticum, 5mM calcium chloride in saline (0.9% NaCl) solution, and feline, canine, or equine serum that had been stored for 0, 30, 90, or 180 days at −20° or −80°C. Following incubation, the corneal weight loss percentage and hydroxyproline concentration in the incubation fluid were calculated and compared among experimental combinations. RESULTS Feline serum was more effective than canine or equine serum for minimizing corneal weight loss. Incubation with feline or equine, but not canine, serum significantly reduced hydroxyproline production. Serum storage duration did not affect corneal weight loss, but the hydroxyproline concentration was greater for corneal specimens that were incubated with serum that was stored for 90 days, compared with that for corneal specimens incubated with serum that was stored for 0, 30, or 180 days. Serum storage temperature did not affect corneal weight loss or hydroxyproline concentration. CONCLUSIONS AND CLINICAL RELEVANCE Results suggested that serum reduced corneal degradation in vitro, and the duration and temperature at which serum was stored did not affect its anticollagenase efficacy.

OBJECTIVE To investigate the safety of daily oral administration of grapiprant to dogs. ANIMALS Thirty-six 9-month-old Beagles of both sexes. PROCEDURES Dogs were randomly assigned to groups that received grapiprant via oral gavage at 0, 1, 6, or 50 mg/kg (total volume, 5 mL/kg), q 24 h for 9 months. Each group contained 4 dogs of each sex (ie, 8 dogs/group), except for the 50 mg/kg group, which included 4 additional dogs that were monitored for an additional 30 days after treatment concluded (recovery period). All dogs received ophthalmologic, ECG, and laboratory evaluations before treatment began (baseline) and periodically afterward. All dogs were observed daily. Dogs were euthanized at the end of the study for necropsy and histologic evaluation. RESULTS All dogs remained clinically normal during treatment, with no apparent changes in appetite or demeanor. Emesis and soft or mucoid feces that occasionally contained blood were observed in all groups, although these findings were more common in dogs that received grapiprant. In general, clinicopathologic findings remained within baseline ranges. Drug-related changes in serum total protein and albumin concentrations were detected, but differences were small and resolved during recovery. No drug-related gross or microscopic pathological changes were detected in tissue samples except mild mucosal regeneration in the ileum of 1 dog in the 50 mg/kg group. CONCLUSIONS AND CLINICAL RELEVANCE Results suggested the safety of long-term oral administration of grapiprant to dogs. Efficacy of grapiprant in the treatment of dogs with osteoarthritis needs to be evaluated in other studies.

OBJECTIVE To compare effectiveness of glycerol, dimethyl sulfoxide (DMSO), and hydroxyethyl starch (HES) solutions for cryopreservation of avian RBCs. SAMPLE RBCs from 12 healthy Ameraucana hens (Gallus gallus domesticus). PROCEDURES RBCs were stored in 20% (wt/vol) glycerol, 10% (wt/vol) DMSO freezing medium, or various concentrations of HES solution (7.5%, 11.5%, and 20% [wt/vol]) and frozen for 2 months in liquid nitrogen. Cells were then thawed and evaluated by use of cell recovery and saline stability tests, cell staining (7-aminoactinomycin D and annexin V) and flow cytometry, and scanning electron microscopy. RESULTS Percentage of RBCs recovered was highest for 20% glycerol solution (mean ± SE, 99.71 ± 0.04%) and did not differ significantly from the value for 7.5% HES solution (99.57 ± 0.04%). Mean saline stability of RBCs was highest for 10% DMSO (96.11 ± 0.25%) and did not differ significantly from the value for 20% HES solution (95.74 ± 0.25%). Percentages of cells with 7-aminoactinomycin D staining but without annexin V staining (indicating necrosis or late apoptosis) were lowest for 10% DMSO freezing medium (3%) and 20% glycerol solution (1%) and highest for all HES concentrations (60% to 80%). Scanning electron microscopy revealed severe membrane changes in RBCs cryopreserved in 20% HES solution, compared with membrane appearance in freshly harvested RBCs and RBCs cryopreserved in 10% DMSO freezing medium. CONCLUSIONS AND CLINICAL RELEVANCE Cryopreservation of avian RBCs with HES solution, regardless of HES concentration, resulted in greater degrees of apoptosis and cell death than did cryopreservation with other media. Transfusion with RBCs cryopreserved in HES solution may result in posttransfusion hemolysis in birds.

OBJECTIVE To validate primer sets for use in reverse transcription quantitative PCR assays to measure gene expression of cytosolic phospholipase A2 (cPLA2) and microsomal prostaglandin E2 synthase 1 (mPGES1) in equine mononuclear cells and determine the effects of firocoxib, a selective cyclooxygenase 2 (COX-2) inhibitor, on COX-2, cPLA2, and mPGES1 gene expression following incubation of mononuclear cells with lipopolysaccharide (LPS). ANIMALS 8 healthy adult horses. PROCEDURES Peripheral blood mononuclear cells were isolated by density gradient centrifugation and incubated at 37°C with medium alone, firocoxib (100 ng/mL), LPS (1 ng/mL or 1 μg/mL), or combinations of firocoxib and both LPS concentrations. After 4 hours, supernatants were collected and tested for prostaglandin E2 (PGE2) concentration with an enzyme inhibition assay, and gene expression in cell lysates was measured with PCR assays. RESULTS Primer pairs for cPLA2 and mPGES1 yielded single products on dissociation curve analyses, with mean assay efficiencies of 102% and 100%, respectively. Incubation with firocoxib and LPS significantly decreased PGE2 supernatant concentrations and significantly reduced COX-2 and mPGES1 gene expression, compared with values following incubation with LPS alone. CONCLUSIONS AND CLINICAL RELEVANCE Primer sets for mPGES1 and cPLA2 gene expression in equine mononuclear cells were successfully validated. Firocoxib significantly decreased LPS-induced COX-2 and mPGES1 expression, suggesting that it may be useful in the control of diseases in which expression of these genes is upregulated.