Search Results

Abstract

Objective—To compare surgical preparation time, surgery and anesthesia times, hospitalization duration, and intra- and postoperative complications between laparoscopic and conventional open cryptorchidectomy in horses.

Design—Retrospective cohort study.

Animals—60 horses that underwent cryptorchidectomy.

Procedures—Medical records were reviewed to identify horses that had undergone cryptorchidectomy from 1991 to 2012. Thirty horses that underwent laparoscopic cryptorchidectomy (case horses) were matched with 30 control horses that had undergone open cryptorchidectomy (ie, inguinal and parainguinal surgical approaches). Horses were matched according to history of previous surgery, testicle location, and type of closure following removal of an undescended unilateral testicle. Duration of surgery, surgical preparation and anesthesia times, hospitalization duration, and number of intra- and postoperative complications were compared between horses that underwent laparoscopic cryptorchidectomy versus open cryptorchidectomy. Comparisons were also made between horses in terms of whether there was a history of previous failed cryptorchidectomy or unknown location of testicle prior to surgery.

Results—Horses that underwent laparoscopic cryptorchidectomy had significantly longer surgery and anesthesia times overall, compared with horses that underwent open cryptorchidectomy. No difference in surgery time was found between case and control horses that had a previous surgical attempt to remove an undescended testicle or in which the testicle location was unknown prior to surgery. Overall, horses undergoing laparoscopy had a nonsignificant increase in intraoperative complications, compared with control horses, and had significantly more postoperative complications.

Conclusions and Clinical Relevance—Horses undergoing laparoscopic cryptorchidectomy had increased surgical preparation time, increased surgery and anesthesia times, and more postoperative complications, compared with horses undergoing open cryptorchictomy. Laparoscopy may be advantageous for a second attempt at cryptorchidectomy or if the testicle location is unknown prior to surgery.

Abstract

Objective—To determine whether inflammation of the jejunum of horses decreases the number of motilin receptors and amounts of motilin receptor mRNA and alters erythromycin lactobionate binding affinity to the motilin receptor in jejunal tissues.

Sample Population—Jejunal segments in 6 adult horses.

Procedure—Each horse was anesthetized, and a ventral median celiotomy was performed; 2 segments of jejunum underwent a sham operation, 2 segments underwent ischemic strangulation obstruction (ISO), and 2 segments underwent intraluminal distension (ILD). Treatments were maintained for 120 minutes. From each segment, full-thickness biopsy samples were collected and smooth-muscle homogenates were prepared. Affinity and distribution of motilin binding to these preparations were determined by use of iodine 125 (¹²⁵I)-labeled synthetic porcine motilin. Via displacement experiments, competition between ¹²⁵I-labeled motilin and erythromycin lactobionate for binding to motilin receptors in the different segments was investigated. A quantitative real-time PCR technique was used to assess motilin receptor mRNA content in the muscle preparations.

Results—Compared with the ISO or ILD segments, the number of motilin receptors was significantly higher in the sham-operated segments; ILD segments contained the lowest number of motilin receptors. The expression of motilin receptor mRNA was significantly decreased in ILD segments but not in ISO segments. Erythromycin lactobionate displacement of ¹²⁵I-labeled motilin from motilin receptors did not differ significantly among the jejunal segments.

Conclusions and Clinical Relevance—Results suggest that downregulation and decreased production of motilin receptors in inflamed jejunal tissue contribute to the altered prokinetic response to erythromycin in horses with gastrointestinal disease.

Abstract

Objective—To identify and characterize motilin receptors in equine duodenum, jejunum, cecum, and large colon and to determine whether erythromycin lactobionate competes with porcine motilin for binding to these receptors.

Sample Population—Specimens of various segments of the intestinal tracts of 4 adult horses euthanatized for reasons unrelated to gastrointestinal tract disease.

Procedure—Cellular membranes were prepared from smooth muscle tissues of the duodenum, jejunum, pelvic flexure, and cecum. Affinity and distribution of motilin binding on membrane preparations were determined by use of ¹²⁵I-labeled synthetic porcine motilin. Displacement studies were used to investigate competition between ¹²⁵I-labeled synthetic porcine motilin and erythromycin lactobionate for binding to motilin receptors in various segments of bowel.

Results—Affinity of ¹²⁵I-labeled synthetic porcine motilin for the equine motilin receptor was estimated to be 6.1nM. A significantly higher number of motilin receptors was found in the duodenum than in the pelvic flexure and cecum. The jejunum had a significantly higher number of motilin receptors than the cecum. Erythromycin lactobionate displacement of ¹²⁵I-labeled porcine motilin from the equine motilin receptor did not differ significantly among various segments of bowel.

Conclusions and Clinical Relevance—Motilin receptors were found in the duodenum, jejunum, pelvic flexure, and cecum of horses. The highest number of motilin receptors was in the duodenum, and it decreased in more distal segments of bowel. Erythromycin lactobionate competed with motilin binding in the equine gastrointestinal tract. This suggests that 1 of the prokinetic actions of erythromycin in horses is likely to be secondary to binding on motilin receptors. (Am J Vet Res 2002;63:1545–1550)

Abstract

Objective—To determine effects of extracorporeal shock wave therapy (ESWT) on healing of wounds in the distal portion of the forelimb in horses.

Animals—6 horses.

Procedures—Five 6.25-cm² superficial wounds were created over both third metacarpi of 6 horses. Forelimbs were randomly assigned to treatment (ESWT and bandage) or control (bandage only) groups. In treated limbs, each wound was treated with 625 shock wave pulses from an unfocused electrohydraulic shock wave generator. In control limbs, each wound received sham treatment. Wound appearance was recorded weekly as inflamed or healthy and scored for the amount of protruding granulation tissue. Standardized digital photographs were used to determine the area of neoepithelialization and absolute wound area. Biopsy was performed on 1 wound on each limb every week for 6 weeks to evaluate epithelialization, fibroplasia, neovascularization, and inflammation. Immunohistochemical staining for A smooth muscle actin was used to label myofibroblasts.

Results—Control wounds were 1.9 times as likely to appear inflamed, compared with treated wounds. Control wounds had significantly higher scores for exuberant granulation tissue. Treatment did not affect wound size or area of neoepithelialization. No significant difference was found for any of the histologic or immunohistochemical variables between groups.

Conclusions and Clinical Relevance—Treatment with ESWT did not accelerate healing of equine distal limb wounds, but treated wounds had less exuberant granulation tissue and appeared healthier than controls. Therefore, ESWT may be useful to prevent exuberant granulation tissue formation and chronic inflammation of such wounds, but further studies are necessary before recommending ESWT for clinical application.

Abstract

Objective—To evaluate the performance of a chemiluminescent endotoxin activity assay in horses with colic and healthy horses.

Animals—20 horses with colic and systemic inflammatory response syndrome (SIRS group), 8 horses with colic with no SIRS (NSIRS group), and 20 healthy horses.

Procedures—Venous blood was collected into EDTA blood collection tubes after completion of a physical examination, and a chemiluminescent endotoxin activity assay was performed within 60 minutes of collection. Medical or surgical interventions and outcome were recorded for each horse.

Results—Mean ± SE endotoxin activity was 0.16 ± 0.05 for healthy horses, 0.18 ± 0.07 for the NSIRS group, and 0.53 ± 0.05 for the SIRS group and was significantly different among the groups. Mean endotoxin activity was significantly higher in the SIRS group than in the NSIRS group and the healthy group. No significant difference between the healthy and NSIRS groups was present. The higher the measured endotoxin activity, the more likely it was for horses to be euthanized.

Conclusions and Clinical Relevance—The chemiluminescent endotoxin assay was easy to use, required a short time to perform, could be completed at the patient's side, and with some modifications, may be a useful component in the clinical assessment and prognostication of horses with colic.

Abstract

Objective—To evaluate whether changes in gastric myoelectrical activity in healthy, awake dogs can be detected via multichannel electrogastrography (EGG).

Animals—6 healthy hound-breed dogs.

Procedures—For each dog, 8-channel EGG was performed after food had been withheld for 12 hours and at 30 minutes after subsequent feeding; 60 minutes after feeding, atropine (0.04 mg/kg) was administered IM to induce ileus, and 30 minutes later, EGG was again performed. Mean cycles per minute (cpm) values of the dominant frequency (a measure of the rhythmicity of gastric electrical activity) and mean power ratios (ie, power measured after treatment divided by the power measured when food was withheld) were calculated. Motility of the gastric antrum was assessed via B-mode ultrasonography during the same phases; contractions determined ultrasonographically were correlated with EGG power for each channel in each phase.

Results—The criterion for stability (SD of the dominant frequency < 15% of the cpm value in at least 3 of the 8 EGG channels) was met in 4 of the 6 dogs (only in long-distance channels). The mean power ratios were significantly higher in the postprandial phase than in the ileus phase. Compared with the postprandial phase, significantly fewer contractions per minute were evident ultrasonographically in the ileus and food-withholding phases. There was a significant and good correlation between EGG power and ultrasonographic findings in all 8 channels.

Conclusions and Clinical Relevance—Electrogastrography may be useful in assessing gastric myoelectrical activities in awake dogs with naturally occurring gastrointestinal disease, including gastric dilatation-volvulus.

Abstract

Objective—To evaluate whether changes in myoelectrical activity in the cecum and large colon of horses can be detected via multichannel electrointestinography (EIG).

Animals—6 healthy mature horses.

Procedures—Each horse underwent 3 EIG procedures. Intestinal myoelectrical activity (cecum and large colon) was recorded during a 20-minute period following IV administration of physiologic saline (0.9% NaCl) solution (20 mL; baseline), erythromycin lactobionate (0.5 mg/kg), or detomidine (0.015 mg/kg); intestinal contractions were concurrently viewed via B-mode ultrasonography. By use of computer software, 8-channel EIG recordings were analyzed and the mean of the dominant frequency (a measure of the rhythmicity of gastric electrical activity) expressed in cycles per minute (cpm) was obtained. Total power (MV²) was calculated, and treatment effect was expressed as the power ratio (ie, treatment-associated power divided by the baseline power).

Results—The dominant frequency cpm values were not stable, and no significant differences between treatments were detected. Compared with the effects of saline solution treatment, detomidine significantly reduced the mean cecal and colonic power ratios. Erythromycin significantly reduced the cecal power ratio and increased the colonic power ratio, although the increase was significant in only 1 channel. Ultrasonographic findings and total power (predominantly from the long-distance electrode pairs) were significantly correlated.

Conclusions and Clinical Relevance—In horses, EIG was useful for assessment of changes in myoelectrical activity in the cecum and large colon. Multiple electrodes should be used to cover a larger area of the intestine, and agreement between multiple channels is needed to make the analysis meaningful.

Abstract

Objective—To compare the effect of extracorporeal shock wave therapy (ESWT) on expression of fibroblast growth factor-7 (FGF-7), transforming growth factor-β1 (TGF-β1), insulin-like growth factor-1 (IGF-1), platelet-derived growth factor-A (PDGF), and vascular endothelial growth factor-A (VEGF) in skin with surgically created skin wounds and intact skin in horses.

Animals—14 healthy horses.

Procedure—8 horses were treated with ESWT at 6 locations along the neck at 36, 24, 12, 6, 2, or 1 hour prior to collection of full-thickness biopsy specimens from each location; a control specimen was collected from a sham-treated location. In 6 horses, 5 full-thickness wounds were created in each forelimb. Wounds in 1 forelimb/horse received ESWT immediately after creation and subsequently on days 7, 14, and 21; wounds in the contralateral forelimb remained untreated. Biopsy specimens were collected from 1 wound on each forelimb on days 7, 14, 21, 28, and 35. Expression levels of FGF-7, TGF-β1, IGF-1, PDGF, and VEGF were assessed in tissue samples from the horses' necks and forelimbs.

Results—In surgically created wounds, ESWT treatment was associated with reduced TGF-β1 expression, compared with expression in control wounds, during the entire study period. At 28 days following wound creation, IGF-1 expression was significantly increased for treated and untreated wounds, compared with findings on days 7, 14, 21, and 35. There was no significant effect of treatment on FGF-7, TGF-β1, IGF-1, PDGF, or VEGF expression in intact skin.

Conclusions and Clinical Relevance—Intervention with ESWT to suppress TGF-β1 may decrease granulation tissue production, resulting in improved wound healing on the distal portion of horses' limbs.

Abstract

Objective—To evaluate the efficacy and effects of labeling equine umbilical cord blood (UCB)– and bone marrow (BM)–derived multipotent mesenchymal stromal cells (MSCs) with an ultrasmall superparamagnetic iron oxide (SPIO) contrast agent and the detection of labeled MSCs by use of MRI.

Sample—UCB MSCs from placental tissues of 5 foals and BM MSCs from 5 horses.

Procedures—UCB and BM MSC cultures were seeded in duplicate (5,000 cells/cm²). One duplicate was incubated with SPIO (50 μg/mL); the other was processed identically, but without SPIO. Mesenchymal stromal cells were expanded in triplicates for 5 passages and assessed for viability and proliferative capacity, labeling efficacy, and labeled cell proportion. For MRI detection, 5 × 10⁶ labeled BM MSCs from passage 1 or 2 were injected into a collagenase-induced superficial digital flexor tendon defect of an equine cadaveric forelimb from 2 horses.

Results—For passages 1, 2, and 3, labeling efficacy and cell proportion for UCB MSCs (99.6% [range, 98.8% to 99.9%], 16.6% [range, 6.5% to 36.1%], and 1.0% [range, 0.4% to 2.8%], respectively) were significantly higher than for BM MSCs (99.2% [range, 97.8% to 99.7%], 4.5% [range, 1.6% to 11.8%], and 0.2% [range, 0.1% to 0.6%], respectively). Labeling was not detectable after passage 3. Viability of MSCs was not affected, but cell doubling time increased in labeled MSCs, compared with that of unlabeled MSCs. On MRI 3-D T2*-weighted fast gradient echo sequences, decreased signal intensity was observed for BM passage 1 MSCs.

Conclusions and Clinical Relevance—Equine UCB and BM MSCs were labeled with SPIO at high efficiencies.