Search Results
You are looking at 1 - 10 of 10 items for
- Author or Editor: Dwayne H. Rodgerson x
- Refine by Access: All Content x
Abstract
Objective—To determine messenger RNA expression of cyclooxygenase (COX)-2, tumor necrosis factor (TNF)-α, and interleukin- (IL)-1β from cultured equine smooth muscle cells (SMC).
Sample Population—Segments of palmar digital artery harvested from 6 clinically normal adult horses.
Procedure—Explants were collected from the tunica media of arteries for primary culture of SMC. Equine mononuclear cells were used as control cells. Subcultured vascular SMC and control cells were exposed to lipopolysaccharide (20 µg/ml and 100 ng/ml, respectively). Northern blot analysis with equine-specific probes for COX-2, TNF-α, and IL-1β was performed, using isolated total cellular RNA.
Results—Although no message was detected for IL-1β or TNF-α in control or endotoxin-exposed equine vascular SMC from all horses, COX-2 underwent a distinct substantial up-regulation after endotoxin exposure. Endotoxin-exposed equine mononuclear cells had up-regulation of IL-1β and TNF-α mRNA.
Conclusions and Clinical Relevance—Increased expression of COX-2 mRNA by equine vascular SMC may be an important early pathophysiologic event in the onset of endotoxemia in horses. Potentiated local vascular production of various prostanoids after increased expression of mRNA for COX-2 may result in vasoactive events observed with laminitis. (Am J Vet Res 2001;62:1957–1963)
Abstract
Objective—To develop methods to isolate, culture, and characterize smooth muscle cells (SMC) from equine palmar digital arteries.
Sample Population—Segments of the medial or lateral palmar digital arteries from the forelimbs of 6 horses.
Procedure—To obtain smooth muscle explants, arterial segments were incised longitudinally. The tunica intima was gently scraped from the underlying tunica media, and explants were obtained from the tunica media. Approximately 18 to 24 explants were obtained from each palmar digital arterial segment. A substrate-attached technique was used to initiate primary culture of SMCCultured cells were identified as SMC, using light microscopy, electron microscopy, reverse transcriptase-polymerase chain reaction (RTPCR), and northern blot analysis. The replication index and serum dependence of equine SMC in culture was characterized by use of bromodeoxyuridine.
Results—The SMC of equine palmar digital arteries were successfully cultured, as confirmed by RT-PCR and northern blot analysis techniques for smooth muscle α-actin and detection of SMC-specific organelles during electron microscopy. When characterized by light and electron microscopy, SMC were found to have undergone phenotypic modulation to a more synthetic phenotype in culture while retaining characteristics of SMC.
Conclusions and Clinical Relevance—Culture of SMC from equine palmar digital arteries via an explant protocol is a viable technique for studying vascular biological mechanisms in horses. In vitro studies of SMC may aid investigators in determining cellular mechanisms involved in disease processes such as laminitis. (Am J Vet Res 2000;61:1602–1608)
Abstract
Objective—To report the postoperative outcome in horses undergoing jejunoileal anastomosis performed with a 2-layer simple continuous technique.
Design—Retrospective study.
Animals—7 horses.
Procedure—Information regarding signalment, clinical signs, findings at surgery, and postoperative complications was obtained from medical records of horses that underwent exploratory ventral midline celiotomy, small intestinal resection, and jejunoileal anastomosis to correct various small intestinal strangulating lesions. Follow-up information was obtained via telephone conversations with owners or trainers.
Results—Six males and 1 female of various breeds aged 10 months to 27 years and weighing 312 to 785 kg (686.4 to 1,727 lb) were included. The most common complications were mild to moderate tachycardia and mild to moderate signs of abdominal pain. Two horses developed incisional infections and soft, fluctuant swelling at the incision site following resolution of the infection. Follow-up time ranged from 7 to 17 months after surgery. Owners reported no further colic episodes and no diet change necessary following surgery. All horses had returned to their intended level of use.
Conclusions and Clinical Relevance—Advantages to the jejunoileal technique include maintaining the normal ileocecal valve and a postoperative recovery period similar to that described following other small intestinal anastomoses. Jejunoileal anastomosis is a viable alternative to ileal bypass. This technique appears to result in a postoperative complication rate similar to that reported following jejunojejunostomy procedures. (J Am Vet Med Assoc 2002;221:541–545)
SUMMARY
Objective
To evaluate analgesic effects after epidural administration of medetomidine to cows, compared with effects of lidocaine hydrochloride and 0.9% NaCI solution.
Animals
6 adult beef cows.
Procedure
3 treatments were administered to each cow, with a 1-week interval between subsequent treatments. Treatments consisted of 5 ml of physiologic saline (0.9% NaCI) solution; 0.2 mg of lidocaine/kg of body weight, not to exceed 100 mg (5 ml); and 15 μg of medetomidine/kg, diluted with 0.9% NaCI solution to provide a volume of 5 ml. Epidural injections were given in the first or second coccygeal space. Heart rate, respiratory rate, and arterial blood pressure values were recorded before injection, 5 and 10 minutes after injection, and at 10-minute intervals thereafter. Onset and duration of analgesia, sedation, and ataxia were recorded. A repeated-measures ANOVA was used to detect differences between treatments.
Results
Epidural administration of 0.9% NaCI solution did not induce analgesia. Lidocaine induced analgesia within 5 to 20 minutes, which lasted 10 to 115 minutes (mean ± SD, 43.3 ± 37.2 minutes). Heart rate decreased during lidocaine-induced analgesia. Heart and respiratory rates decreased, but blood pressure remained unchanged, after medetomidine administration. Medetomidine induced analgesia within 5 to 10 minutes, which lasted 412 ± 156 minutes. Mild to moderate sedation and moderate ataxia were observed. Two cows became recumbent, but were easily coaxed to stand. Medetomidine-induced salivation and increased frequency of urination were observed in all cows.
Conclusions and Clinical Relevance
Epidural administration of medetomidine induced prolonged analgesia that was suitable for perineal surgery, post-operative analgesia, and relief of continuous straining. (Am J Vet Res 1998;59:162–167)
