In Vitro Effects of Epidermal Growth Factor or Insulin-Like Growth Factor on Tenoblast Migration on Absorbable Suture Material

OBJECTIVE: To determine the effects of epidermal growth factor (EGF) or insulin-like growth factor (IGF) on tenoblast migration on absorbable suture material using an in vitro model. STUDY DESIGN: An in vitro evaluation of tenoblast migration. ANIMAL OR SAMPLE POPULATION: Segments of the long digital flexor tendon were obtained from Cobb chickens (9-11 weeks old) immediately after the birds were euthanatized. METHODS: Tissue culture explants of tendons containing absorbable suture material were treated with either EGF or IGF. Tenoblast migration was assessed daily using an inverted microscope equipped with bright field and phase optics. Tenoblast migration was assessed according to the following criteria: time of first cell appearance, percent of explant interfaces producing cells, migration distance, and terminal migration index at 120 and 168 hours. RESULTS: EGF had a stimulatory effect on tenoblast migration for cells originating from the endotenon interfaces. No significant effect was noted on migration distance for cells originating from epitenon interfaces. A stimulatory effect on the percentage of interfaces producing cells and a significant decrease in time of first cell appearance were also observed after EGF treatment. IGF-stimulated cell migration distance for epitenon interfaces but this stimulatory effect did not occur at a higher concentration. IGF was inhibitory to percent of epitenon and endotenon interfaces producing cells but decreased time of first cell appearance at low concentration. CONCLUSIONS: Using an in vitro model, EGF had a stimulatory effect on tenoblast migration. IGF was stimulatory at low concentration levels but inhibitory at a higher concentration. Increased migration distance was observed for endotenon interfaces after EGF treatment and for epitenon interfaces after IGF treatment. CLINICAL RELEVANCE: EGF or IGF might enhance tendon repair if they could be delivered to the repair site. Incorporation of EGF or IGF into suture material would allow slow release and prolonged exposure of migrating tenoblasts to growth factors.     

Behavioral responses following eight anesthetic induction protocols in horses

Objective To compare behavioral characteristics of induction and recovery in horses anesthetized with eight anesthetic drug protocols. Study design Randomized prospective experimental study. Animals Eight horses, 5.5 ± 2.4 years (mean ± SD) of age, and weighing 505 ± 31 kg. Methods After xylazine pre‐medication, each of eight horses was anesthetized on four occasions using one of eight different anesthetic induction protocols which incorporated various combinations of ketamine (KET), propofol (PRO), and thiopental (THIO): THIO 8 mg kg^?1; THIO 6 mg kg^?1 + PRO 0.5 mg kg^?1; THIO 4 mg kg^?1 + PRO 1 mg kg^?1; THIO 2 mg kg^?1 + PRO 1.5 mg kg^?1; KET 2 mg kg^?1; KET 1.5 mg kg^?1 + PRO 0.5 mg kg^?1; KET 1 mg kg^?1 + PRO 1 mg kg^?1; KET 0.5 mg kg^?1 + PRO 1.5 mg kg^?1. Quality of induction and recovery were scored from 1 (poor) to 5 (excellent), and time taken to achieve lateral recumbency, first movement, sternal recumbency, and standing were evaluated. Results Time taken to achieve lateral recumbency after drug administration differed significantly (p < 0.0001) among the various combinations, being shortest in horses receiving THIO‐8 (mean ± SD, 0.5 ± 0.3 minutes) and longest in horses receiving KET‐2 (1.4 ± 0.2 minutes). The best scores for induction quality were associated with KET‐1.5 + PRO‐0.5, and the worst scores for induction quality were associated with KET‐2, although the difference was not significant. Time to first movement varied significantly among drug protocols (p = 0.0133), being shortest in horses receiving KET‐2 (12.7 ± 3.6 minutes) and longest in horses receiving THIO‐8 (29.9 ± 1.5 minutes). Horses receiving THIO‐8 made the greatest number of attempts to attain sternal posture (6.5 ± 4.7) and to stand (1.6 ± 0.8). Horses in the THIO‐8 treatment also received the poorest recovery scores (3.3 ± 1.0 and 3.0 ± 0.7 for sternal and standing postures, respectively). The best recovery scores were associated with combinations comprised mainly of propofol. Conclusions Combining propofol with either ketamine or thiopental modifies behaviors associated with use of the individual drugs. Clinical relevance Quality of early anesthesia recovery in horses may be improved by some combinations of propofol with either thiopental or ketamine.     

The Effect of Laparoscopic Versus Open Ovariectomy on Postsurgical Activity in Small Dogs

Objective— To describe a technique for laparoscopic ovariectomy (LapOVE) in small dogs, and compare the surgical time, complications, and postoperative activity of dogs undergoing LapOVE to those undergoing conventional traditional open ovariectomy (OOVE).
Study Design— A randomized, controlled clinical trial.
Animals— Intact small breed (<10 kg) female dogs (n=20).
Methods— Ventral median celiotomy was performed for OOVE. A 2-midline portal technique using a 3.5 mm laparoscope port and a 6 mm instrument portal was used for LapOVE. An accelerometer was attached to the collar of each dog to record 24-hour preoperative and 48-hour postoperative activity. Total activity counts recorded before surgery were compared with total counts recorded after surgery. The percent change in counts after surgery was compared between OOVE- and LapOVE-treated dogs.
Results— No major complications occurred and surgical time for LapOVE was significantly longer than for OOVE cases ( P =.005). Dogs in the LapOVE group had a 25% decrease in total activity counts after surgery (95% confidence interval [CI]: 11–38%), whereas dogs in the OOVE group had a 62% decrease in total activity counts after surgery (95% CI: 48–76%).
Conclusions— Both procedures were performed with reasonable surgical times and without major complication. Postoperative activity, as measured by accelerometry, was significantly different between the 2 groups.
Clinical Relevance— Laparoscopy is a safe method for ovariectomy in small dogs and results in increased postoperative activity counts when compared with an open technique.     

A Comparison of the Synthes 4.5-mm Cannulated Screw and the Synthes 4.5-mm Standard Cortex Screw Systems in Equine Bone

Objective —To determine risk of failure of the Synthes 4.5-mm cannulated screw system instrumentation in equine bone and to compare its application with the Synthes 4.5-mm standard cortex screw system.
Study Design —The maximum insertion torque of the cannulated and standard cortex screw systems were compared with the ultimate torsional strengths of the equipment. Pullout strength and ultimate tensile load of cannulated and standard cortex screws were also determined.
Sample Population—Paired equine cadaver third metacarpal and third carpal bones.
Methods —Maximum insertion torque and ultimate torsional strengths were determined by using an axial-torsional, servohydraulic materials testing system and a hand-held torquometer. Pullout tests were performed by using a servohydraulic materials testing system.
Results —Maximum insertion torque of all cannulated instrumentation was less than ultimate torsional strength at all locations ( P < .05). Maximum insertion torques of cannulated taps and screws were greater than for standard taps and screws in the third carpal bone ( P < .002). Pullout strength of the cannulated screws was less than the standard cortex screws at all sites ( P < .001). Cannulated screws broke before bone failure in all but one bone specimen. Conclusions—The risk of cannulated instrument or screw failure during insertion into bone is theoretically low. The relatively low pullout strength of the cannulated screws implies that the interfragmentary compression achievable is likely to be less than with standard cortex screws. Clinical Relevance—The relatively low pullout strength of the cannulated screw suggests that its risk of failure during fracture repair is greater than with the standard cortex screw.     

In Vivo Evaluation of Intramedullary Interlocking Nail Fixation of Transverse Femoral Osteotomies in Foals

Objective—To evaluate an intramedullary interlocking nail for stabilization of transverse femoral osteotomies in foals.
Study Design—A transverse osteotomy and restabilization with an intramedullary interlocking nail was performed on the right femur in three foals and the left femur in three foals. Animals—Six foals weighing 149 to 207 kg.
Methods—The femur was destabilized with a transverse middiaphyseal osteotomy and repaired with a 0.5-in (12.7 mm) interlocking nail. The implanted femurs were radiographed monthly until completion of the study 6 months after surgery. At the completion of the study, all foals were observed for evidence of lameness, gluteal thickness was determined by ultrasonographic measurement, and a necropsy was performed.
Results—Healing was satisfactory in all foals. Five of the six had osseous bridging of the osteotomy apparent radiographically by 3 to 4 months. The sixth foal had postoperative infection but was healed radiographically in 5 months. There was a mean decrease in gluteal muscle thickness of 6.6 mm ( P = .04) in the operated limb of the five foals that healed without complication. Two foals were lame at the completion of the project; one foal with varus deformities of the contralateral limb was mechanically lame, and another was grade 2/5 lame on the operated limb. On necropsy, there was circumferential enlargement of the diaphysis of all operated limbs with the majority of the callus at the cranial and medial aspects of the cortex. All nails were solid within the medullary cavity.
Conclusions —The intramedullary interlocking nail provided adequate stabilization for repair of the transverse osteotomy.
Clinical Relevance —Further investigation is warranted before use for stabilization of spontaneously occurring fracture configurations.     

Comparison of a New Braid Fixation System to an Interlocking Intramedullary Nail for Tibial Osteotomy Repair in an Ovine Model

Objectives— To compare bone healing of tibial osteotomy repaired with Nitinol wire braid and hardened steel rods (Braid system) and polymethylmethacrylate bone cement with an interlocking intramedullary (IM) nail fixation in an ovine model.
Study Design— In vitro and in vivo experimental study.
Animals— Adult female sheep (n=22).
Methods— Using sheep tibia, a middiaphyseal transverse osteotomy was performed in the right tibia, which were then randomly assigned to the Braid system group or IM nail group (n=5). The left tibia were used as controls. The torsional properties of tibial constructs were compared. The study was repeated in vivo in 12 sheep and mechanical properties and bone healing were evaluated at 12 weeks.
Results— In vitro, there was no significant difference in torsional stiffness between the groups. In vivo, operative time for the Braid system group was significantly shorter than the IM nail group. At 12 weeks, there were no significant differences in maximum torque and torsional stiffness between IM nail and Braid system groups nor were there significant radiographic or histologic differences between the groups.
Conclusions— The Braid system might decrease operative time for repair of transverse middiaphyseal tibial fractures and result in similar bone healing at 12 weeks after surgery compared with an interlocking IM nail repair.
Clinical Relevance— A Nitinol Braid system may be a treatment option for transverse midshaft tibial fractures.