The effect of topical tripeptide-copper complex on healing of ischemic open wounds

OBJECTIVE: To evaluate the effects of topical glycyl-L-histidyl-L-lysine tripeptide-copper complex (TCC; Iamin 2% Gel; Procyte Corporation, Redmond, WA) on healing in ischemic open wounds. STUDY DESIGN: Experimental study. SAMPLE POPULATION: Twenty-four adult male Sprague-Dawley rats. METHODS: Rats were divided into 3 groups: topical TCC, topical TCC vehicle (hydroxypropyl-methylcellulose), and no treatment (control). Six-mm-diameter, full-thickness wounds were created within an ischemic bipedicle skin flap on the dorsum of each rat. Each day, for 13 days, wound margins were traced, and the TCC and TCC vehicle groups were treated topically. Tracings were scanned, and wound perimeter and area were calculated. On days 6, 10, and 13, selected wounds were biopsied and analyzed for tumor necrosis factor alpha (TNF-alpha) and matrix metalloproteinases (MMP) 2 and 9. RESULTS: A significant decrease in wound area was seen in the TCC group, but not the vehicle group, when compared with the control group on days 3 to 5, 6 to 9, and 11 to 13 and when TCC was compared with TCC vehicle on days 3 and 9. On day 13, initial wound area had decreased by 64.5% in the TCC group, 45.6% in the vehicle group, and 28.2% in the control group. On days 6, 10, and 13, TCC-treated wounds contained significantly lower concentrations of TNF-alpha and MMP-2 and MMP-9 than control wounds. CONCLUSION: Topical TCC resulted in accelerated wound healing in ischemic open wounds. CLINICAL RELEVANCE: Topical TCC is an effective stimulant of healing of ischemic open wounds in rats and may have an application for the treatment of chronic wounds in other species. Clinical evaluation of topical TCC is warranted.     

Effect of dorsal hip loading,sedation, and general anesthesia on the dorsolateral subluxation score in dogs

OBJECTIVE: To determine whether dorsal loading of the pelvis and type of chemical restraint affected the dorsolateral subluxation (DLS) score of dog hips. STYDY DESIGN: In vivo testing of diagnostic method. ANIMALS: Labrador retrievers, Greyhounds, and crosses between both breeds (n = 119 dogs). METHODS: Dorsal load was applied to the hips through a strap that was placed over the hips, and the peak vertical and steady-state vertical, ground-reaction forces exerted on the stifles were measured in the DLS position. The DLS score was measured with their hips under dorsal load and compared with the DLS score without load. For 24 dogs, the DLS score was measured both under chemical restraint (medetomidine) and under general anesthesia. Wilcoxon-signed rank test and paired t test was used to compare effects of dorsal load and restraint method on the left and right DLS hip score, and P <.05 was considered significant. RESULTS: Both stifles together accepted median 15% body weight in the vertical plane in the unloaded steady state. Loading the hips increased the steady-state, vertical ground-reaction force to 34% body weight. At 8 months of age, loading significantly decreased the DLS score from 65% +/- 11% (mean +/- SD) to 60% +/- 12% for left hips and 66% +/- 11% to 63% +/- 13% for right hips. The left hip DLS score was affected by load more consistently than the right hip. In general, loading the hips decreased the DLS score in all breeds by 4% to 6% except for the greyhounds, in which the DLS score was unchanged by dorsal loading. When grouped by their DLS scores, load significantly decreased DLS scores in dogs with unloaded scores greater than 55% (nondysplastic), whereas DLS scores of dogs with unloaded scores between 55% and 45% (dysplastic) and less than 45% did not change significantly with load. Unloaded scores did not change significantly when compared under sedation versus general anesthesia. However, load significantly decreased the DLS score under general anesthesia for the left hip but not for the right hip. CONCLUSIONS: Less than half of the vertical ground-reaction force normally exerted by the hindlegs of a standing dog was sufficient to induce hip subluxation in the DLS position. Although dorsal loading approximately doubled the steady-state, vertical ground-reaction force, the decrease in the DLS score under load was never greater than 6%. Furthermore, the DLS scores of dogs most likely to be dysplastic (based on DLS scores <45%) were not affected by load, whereas load slightly decreased DLS cores of dogs with DLS scores greater than 55%. CLINICAL RELEVANCE: External influences can change the DLS score significantly, but the magnitude of change is unlikely to be of clinical importance, making the method useful as a field screening test for both dysplastic and nondysplastic hips in young dogs.     

Radiosensitivity and capacity for radiation-induced sublethal damage repair of canine transitional cell carcinoma (TCC) cell lines

Understanding the inherent radiosensitivity and repair capacity of canine transitional cell carcinoma (TCC) can aid in optimizing radiation protocols to treat this disease. The objective of this study was to evaluate the parameters surviving fraction at 2 Gy (SF(2) ), α/β ratio and capacity for sublethal damage repair (SLDR) in response to radiation. Dose-response and split-dose studies were performed using the clonogenic assay. The mean SF(2) for three established TCC cell lines was high at 0.61. All the three cell lines exhibited a low to moderate α/β ratio, with the mean being 3.27. Two cell lines exhibited statistically increased survival at 4 and 24 h in the dose-response assay. Overall, our results indicate that the cell lines are moderately radioresistant, have a high repair capacity and behave similarly to a late-responding normal tissue. These findings indicate that the radiation protocols utilizing higher doses with less fractionation may be more effective for treating TCC.     

Comparison of three radiographic methods for diagnosis of hip dysplasia in eight-month-old dogs.

OBJECTIVE: To compare the accuracy of the extended-hip radiographic (EHR) score, the distraction index (DI), and the dorsolateral subluxation (DLS) score for identifying hip dysplasia in dogs at 8 months of age. DESIGN: Cohort study ANIMALS: 129 Labrador Retrievers, Greyhounds, and Labrador Retriever-Greyhound crossbreds. PROCEDURE: Radiography was performed when dogs were 8 months of age. Dogs were euthanatized at 8 to 36 months of age; hip dysplasia was diagnosed at the time of necropsy on the basis of results of a gross examination of the articular cartilage of the hip joints for signs of osteoarthritis. RESULTS: The EHR score, DI, and DLS score at 8 months of age were all significantly correlated with degree of cartilage degeneration at necropsy. Sensitivity and specificity of using EHR score at 8 months of age to diagnose hip dysplasia (scores > 3 were considered abnormal) were 38 and 96%, respectively; sensitivity and specificity of using DI (values > 0.7 were considered abnormal) were 50 and 89%; and sensitivity and specificity of using DLS score (scores < 55% were considered abnormal) were 83 and 84%. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggested that specificities of the 3 methods for diagnosing hip dysplasia in dogs at 8 months of age were similar. However, the DLS score had higher sensitivity, indicating that there were fewer false-negative results.     

Evaluation of a percutaneously controlled hydraulic occluder in a rat model of gradual venous occlusion

OBJECTIVE: To evaluate the efficacy of a percutaneously controlled hydraulic occluder (HO) in a rat model of gradual venous occlusion. STUDY DESIGN: Experimental study. ANIMALS: Ten male Sprague-Dawley rats. METHODS: HOs and perivascular transit time ultrasound flow probes were applied to the caudal vena cava (CVC). Occluders in group I rats (n=6) were gradually attenuated over 8 weeks, whereas occluders in group II rats (n=4) were not attenuated. Vena caval blood flow measurements were performed weekly in all rats for 8 weeks. After euthanasia, the CVC was evaluated grossly and by histopathology. RESULTS: Premature occlusion of the vena cava occurred during the 1st week in 3 rats (1 in group I, 2 in group II) because of kinking of the vena cava between the HO and the flow probe. For the remaining rats, mean blood flow in group I decreased significantly from 40.71 mL/min/kg at baseline to 4.68 mL/min/kg at 8 weeks (P=.0094, power=0.91). Group II rats maintained vena caval blood flow at all times during the study. Complete occlusion of the vena cava was confirmed at necropsy in all group I rats. CONCLUSIONS: Gradual occlusion of the CVC of rats was achieved with HOs over 8 weeks. This model is limited by the size of the experimental animals and comparatively large implants. CLINICAL RELEVANCE: HOs may provide a method for gradual occlusion of congenital portosystemic shunts.     

Urodynamic effects of a percutaneously controlled static hydraulic urethral sphincter in canine cadavers

OBJECTIVE: To describe a percutaneously controlled static hydraulic urethral sphincter (SHUS) and evaluate urodynamic effects of the SHUS in canine cadavers. SAMPLE POPULATION: Cadavers of 6 adult female dogs. PROCEDURE: Cadavers were obtained immediately after dogs were euthanatized. Baseline maximal urethral closure pressure (MUCP) and cystourethral leak point pressure (CLPP) were measured by use of a urethral pressure profilometer. An SHUS system was constructed by use of a silicone vascular occluder and subcutaneous infusion port. The SHUS system was then placed around the pelvic urethra in each cadaver. Measurements of MUCP and CLPP were repeated after varying occlusion of the SHUS (0%, 25%, and 50% occlusion). Baseline MUCP and CLPP values were compared with values obtained at 0%, 25%, and 50% occlusion of the SHUS by use of repeated-measures ANOVA. RESULTS: Mean +/- SD MUCP for canine cadavers was 7 +/- 1.3 cm H2O at baseline, which increased to 127 +/- 53 cm H2O after 50% occlusion of the SHUS. Mean CLPP was 11 +/- 8.6 cm H2O at baseline, which increased to 73 +/- 38 cm H2O after 50% occlusion of the SHUS. Mean MUCP and CLPP were significantly associated with the amount of occlusion. CONCLUSIONS AND CLINICAL RELEVANCE: The SHUS had positive effects on MUCP and CLPP in canine cadavers. Therefore, additional evaluation of the SHUS in live dogs is warranted.     

Transverse ulnar bone transport osteogenesis: a new technique for limb salvage for the treatment of distal radial osteosarcoma in dogs

Objective— To develop instrumentation and a technique for transverse ulnar bone transport osteogenesis in dogs.
Study Design— Cadaveric study and in vivo validation (1 dog).
Sample Population— Paired cadaveric antebrachii (n=10 dogs) and 1 live dog.
Methods— Circular fixator constructs were applied and fitted with reeling or linear motors designed to transport an ulnar segment transversely into a defect created by excising the distal 50% of the ipsilateral radius. A longitudinal osteotomy of the adjacent ulna was created and the segment was transported across the radial defect. Pre- and post-distraction CT scans were used to compare the efficacy of each construct. The procedure was performed unilaterally in a live dog using the reeling motor (RM) construct.
Results— Both constructs effectively transported the ulnar segment into the defect. Subjectively, the RMs were easier to apply and operate. No significant differences were observed in the objective measures of efficacy between the 2 construct types. The live dog produced viable regenerate bone after transverse ulnar bone transport.
Conclusions— Transverse ulnar bone transport should be considered a potential method for limb salvage in dogs with osteosarcoma (OSA) of the distal radius. The RMs were effective and clinically applicable.
Clinical Relevance— Transverse ulnar bone transport osteogenesis affords the benefits of longitudinal radial bone transport osteogenesis, allowing resolution of large longitudinal radial defects in a substantially less time as a result of shortening the transport distance. This would be beneficial when treating conditions such as OSA where minimizing convalescence and maximizing quality of life is a priority.     

Use of IMEX SK-circular external fixator hybrid constructs for fracture stabilization in dogs and cats

Complex long-bone fractures with short juxta-articular fracture segments can be difficult to manage. Recently, IMEX Veterinary, Inc., began producing titanium hybrid rods that can be secured to ring components of the IMEX circular external skeletal fixation system to create SK-circular hybrids. In this case series, SK-circular hybrids were used to stabilize long-bone fractures (two femoral, one humeral, and three tibial fractures) with short distal bone segments in three dogs and three cats with body weights ranging from 1.9 to 15 kg (mean, 6.7 kg; median, 5.4 kg). Although three cases required surgical revision, animals ambulated well and all fractures obtained union. Time to radiographic union ranged from 62 to 137 days (mean, 90 days; median, 84 days). The functional outcome was considered excellent in all six cases.     

Calcium as a mediator of adrenocorticotrophic hormone action on adrenal protein synthesis

Calcium stimulates leucine incorporation into protein during incubations of sections and cell-free preparations of the rat adrenal. Like adrenocorticotrophic hormone (ACTH) action, calcium enhances the transfer of amino acid from transfer RNA to protein. Stimulation of leucine incorporation by ACTH and cyclic adenosine monophosphate is best observed when sections are incubated in limiting calcium concentrations.