Wendy I. Baltzer

Accelerometer validity and placement for detection of changes in physical activity in dogs under controlled conditions on a treadmill.

The objective of the research was to determine the optimal location and method of attachment for accelerometer-based motion sensors, and to validate their ability to differentiate rest and increases in speed in healthy dogs moving on a treadmill. Two accelerometers were placed on a harness between the scapulae of dogs with one in a pouch and one directly attached to the harness. Two additional accelerometers were placed (pouched and not pouched) ventrally on the dogs collar. Data were recorded in 1s epochs with dogs moving in stages lasting 3 min each on a treadmill: (1) at rest, lateral recumbency, (2) treadmill at 0% slope, 3 km/h, (3) treadmill at 0% slope, 5 km/h, (4) treadmill at 0% slope, 7 km/h, (5) treadmill at 5% slope, 5 km/h, and (6) treadmill at 5% slope, 7 km/h. Only the harness with the accelerometer in a pouch along the dorsal midline yielded statistically significant increases (P<0.05) in vector magnitude as walking speed of the dogs increased (5-7 km/h) while on the treadmill. Statistically significant increases in vector magnitude were detected in the dogs as the walking speed increased from 5 to 7 km/h, however, changes in vector magnitude were not detected when activity intensity was increased as a result of walking up a 5% grade. Accelerometers are a valid and objective tool able to discriminate between and monitor different levels of activity in dogs in terms of speed of movement but not in energy expenditure that occurs with movement up hill.

Dystrophin-deficient muscular dystrophy in a Weimaraner.

A 2-year-old, male Weimaraner with muscular dystrophy was presented with generalized muscle atrophy of the limbs; hypertrophy of the neck, infraspinatus, and lingual muscles; dysphagia; and regurgitation. Unilateral cryptorchidism, unilateral renal agenesis, and hiatal hernia were also detected. Spontaneous muscle activity was identified on myography. Serum creatine kinase was markedly elevated. Immunohistochemical staining for dystrophin was restricted to suspected revertant (characteristics of immaturity) fibers. Histologically, skeletal myofiber degeneration, endomysial fibrosis, and mineralization were present. Following euthanasia, necropsy revealed hypertrophy of the diaphragm and cardiac muscle fibrosis. This case of muscular dystrophy represents a slowly progressive form with organ agenesis.

Influence of transfusion technique on survival of autologous red blood cells in the dog.

OBJECTIVE To determine the effect of 3 differing transfusion techniques on survival of autologous canine RBCs. DESIGN Prospective, blinded study. SETTING University Teaching Hospital. ANIMALS Nine healthy dogs. INTERVENTIONS Three distinct preparations of RBCs, each representing ~1% of red cell mass, were generated for each dog by biotinylation of RBCs at varying biotin densities. Labeled cells were transfused using 3 techniques (gravity, volumetric pump, syringe pump). Serial determinations of red cell survival were carried out by flow-cytometric analysis of RBCs collected at 7-day intervals for 49 days. In vitro analysis of the effect of transfusion methods on RBC integrity and osmotic fragility were carried out in 7/9 dogs. MEASUREMENTS AND MAIN RESULTS RBCs administered via volumetric and syringe pumps exhibited a marked decrease in short-term probability of survival compared with RBCs delivered by gravity flow. At 24 hours, only 4/8 and 1/7 dogs had surviving cell populations delivered by volumetric and syringe pump, respectively, compared with 8/8 dogs which had surviving cell populations delivered by gravity flow. Circulating half-life of cells surviving at 24 hours after delivery by volumetric pump was not significantly different to that delivered by gravity flow. No significant effect on in vitro RBC integrity or osmotic fragility was detected in relation to transfusion technique. CONCLUSIONS Delivery of autologous canine RBCs via mechanical delivery systems was associated with a high risk for early loss of transfused cells.

Shoulder Arthrodesis in14 Dogs

OBJECTIVES To report surgical technique and clinical outcome of shoulder arthrodesis in dogs. STUDY DESIGN Multicenter clinical case series. ANIMALS Dogs (n = 14). METHODS Shoulder arthrodesis featured craniolateral plate and screw application, with application of a 2nd plate and screws craniolaterally or caudolaterally in 5 shoulders. Implants included the locking string of pearls (SOP)™ plate in 7 shoulders. Subjective preoperative, 5-8 weeks postoperative, and 11-16 weeks postoperative clinical and radiographic findings were documented. Owner questionnaire evaluation of outcome was performed 6-20 months postoperatively. RESULTS Mean angle of arthrodesis was 114° (range 102°-122°). Progression of arthrodesis was noted in 13/14 cases at both the 5-8 and 11-16 weeks postoperative radiographic assessments. Nine complications occurred in 7/14 dogs, graded as catastrophic in 2/9, major in 2/9, and minor in 5/9. Where morbidity was successfully managed, 11-16-week and 6-10-month postoperative limb function was positive on both veterinary and owner evaluations in almost all cases, and in several, functional lameness was considered sufficiently mild as to be imperceptible on subjective veterinary evaluation. Where present, limb circumduction was noted as the major feature of persistent lameness. CONCLUSIONS Shoulder arthrodesis in dogs results in acceptable limb function and should be considered for the management of debilitating shoulder pathology despite a high incidence of complications. Application of the SOP plate to aid shoulder arthrodesis warrants further study.

Randomized, blinded, placebo-controlled clinical trial of n-acetylcysteine in dogs with spinal cord trauma from acute intervertebral disc disease

Study Design. The effect of N-acetylcysteine administration intravenously before hemilaminectomy surgery on neurologic outcome and 15F2t isoprostane excretion in dogs was examined in a blinded, placebo-controlled trial. Objective. To determine the effect of N-acetylcysteine administration on urinary 15F2t isoprostane excretion and neurologic outcome following hemilaminectomy for intervertebral disc disease. Summary of Background Data. Oxidative stress is a mediator of secondary injury to the spinal cord following trauma. Acute intervertebral disc disease is associated with increased oxidative damage in dogs. N-acetylcysteine has preserved neurologic function following experimental spinal cord injury. Methods. Seventy dogs with naturally occurring acute intervertebral disc disease were administered either with saline placebo or N-acetylcysteine intravenously before hemilaminectomy surgery. Serial neurologic examinations were performed before and 1, 2, 7, 14, and 42 days following treatment. Urinary excretion of 15F2t isoprostane excretion was determined before treatment and 1 hour after surgery. Results. Analysis of subjective data did not reveal any significant effect of N-acetylcysteine on neurologic outcome or rate of improvement of neurologic score in the 42 days following treatment. Urinary 15F2t isoprostane excretion was not significantly different between treatment groups (P > 0.05). Conclusion. N-acetylcysteine intravenously before hemilaminectomy has no effect on urinary 15F2t isoprostane excretion or neurologic outcome. Treatment of dogs with the antioxidant N-acetylcysteine before hemilaminectomy, while not detrimental, does not affect neurologic outcome in the 42 days following surgery.

The effect of agility exercise on eicosanoid excretion, oxidant status, and plasma lactate in dogs

BackgroundThe objective was to determine the effects of agility exercise on dogs of different skill levels with respect to urinary eicosanoids, urinary 15F2t-isoprostane (lipid peroxidation marker) and hematological/biochemical changes in plasma. Fifteen adult dogs had blood and urine samples obtained prior to, immediately and 4-hours following an agility exercise.ResultsHematocrit, red blood cells (RBC), albumin, and hemoglobin increased following exercise, with greatest increases correlating to increased skill group (novice, intermediate, masters); at 4-hours post-exercise, hematocrit, RBC, and hemoglobin were decreased. Phosphorus increased following exercise with the greatest increase in novice and intermediates. Plasma lactate increased 3.6-fold in masters, 3.2-fold in intermediates, and 1.2-fold in novice dogs. Urine thromboxane B2 (TXB2) more than tripled 4-hours post-exercise while 6-keto prostaglandin F1α (PGF1α, prostacyclin metabolite), prostaglandin E2 metabolites (13,14-dihydro-15-keto-prostaglandin A2 and 13,14-dihydro-15-keto-prostaglandin E2), and 13,14-dihydro-15-keto prostaglandin F2α were unaffected as determined by a competitive enzyme immunoassay and standardized by division with urine creatinine. Urine 15F2t-isoprostane increased insignificantly.ConclusionsAlterations in the plasma post-exercise were likely due to hemoconcentration from insensible water loss, splenic contraction and sympathetic stimulation while 4-hours later autohemodilution reduced RBC parameters. Elevations in plasma lactate and urinary TXB2 correlated with advanced skill level/speed of the dogs.

Achilles tendon repair in dogs using the semitendinosus muscle: surgical technique and short-term outcome in five dogs.

OBJECTIVE To describe augmentation of primary Achilles tendon repair using suture with a semitendinosus muscle flap and report outcome in 5 dogs. STUDY DESIGN Prospective clinical study. ANIMALS Dogs (n=5) with Achilles tendon rupture (n=6). METHODS After tendon repair with #2 polypropylene in a 3-loop pulley suture pattern, the lateral one-half of the semitendinosus muscle was transected from the ischium, rotated distally then sutured with #2 polypropylene to the calcaneus in a 3-loop pulley pattern. The epitenon was sutured to the muscle flap fascia with interrupted sutures. All dogs had a bivalved cast for 2 weeks then a cranial splint for 2-6 weeks. Lameness scores (0=stands and walks normally to 4=non-weight-bearing lameness, plantigrade stance on affected pelvic limb) were determined every 2-3 weeks postoperatively for 12 weeks. Outcome was determined from telephone questionnaire of owners. RESULTS Four had lameness scores of 0, the 5th had a score of 1 at 12 weeks. Three owners were very satisfied with outcome. Minor complications included cast sores (2 dogs), infection (2), and acute swelling (1); 1 major complication occurred (infection resulting in reoperation). CONCLUSIONS Semitendinosus flap augmentation resulted in early return to function without prolonged postoperative immobilization. Three dogs returned to full work/activity after repair. CLINICAL RELEVANCE Augmentation of primary Achilles tendon repair with a semitendinosus flap can be considered in dogs with chronic rupture but further investigation of the long-term outcome using this technique is needed.

A Novel Aortic Coarctation Model for Studying Hypertension in the Pig

We have developed a reproducible renovascular model of hypertension via a controllable, suprarenal aortic coarctation in the pig. This model has many potential applications, including investigation of the effects of acute hypertension in the conscious animal; identification of cardiac and vascular adaptations to chronic hypertension and their reversal; determining the effect of pharmacologic agents or other interventions on hypertension; and furthering our understanding of the implications of chronic hypertension on neurologic function. A totally implantable system was devised by attaching a reinforced silicone vascular occluder to a vascular access port. The occluder was placed around the suprarenal aorta proximal to the diaphragm. Ten pigs were made hypertensive by sequentially inflating the occluder. In six pigs, telemetric monitoring of blood pressure was used to determine when the pigs had reached target pressures (mean arterial blood pressure >150 mm Hg). Four pigs did not have telemetry units placed and blood pressure and heart rate were monitored for 4 weeks by periodically restraining the pigs in a sling. Two pigs reversed their occlusion due to presumed technical errors; the remaining pigs were studied for 4 ( n = 5) or 8 ( n = 3) weeks and then euthanized. Advantages of this model of aortic coarctation are that the occlusions are performed in awake animals and excessive occlusion of the aorta resulting in neurologic dysfunction or other distress to the animal can be easily corrected by simply withdrawing a small amount of the fluid used for inflation of the occluder. Additionally, removal of the constriction does not require a second surgical procedure.

Inter- and intratester reliability of anthropometric assessment of limb circumference in labrador retrievers.

OBJECTIVE To report a standardized method of, and determine inter- and intratester reliability for, anthropometric assessment of limb circumference in dogs. STUDY DESIGN Prospective blinded study. ANIMALS Labrador Retrievers (n = 20). METHOD Unsedated dogs were manually restrained in lateral recumbency and triplicate measurements of limb circumference at the level of the proximal antebrachium, mid brachium, proximal crus, and mid-thigh were made using the Gulick II tape measure in the morning and afternoon of the same day. Observers were blinded to measurements made during each occasion and those made by co-observers. Estimates of inter- and intratester reliability were made for first and mean measurements using intra-class correlation coefficients (ICC). RESULTS Measurements of the proximal antebrachium were made with moderate to fair intratester reliability by all observers with ICCs ranging from 0.68-0.78 (1st measurement) and 0.67-0.78 (mean measurement), and moderate to fair intertester reliability with ICCs of 0.66-0.68 (1st measurement) and 0.70-0.72 (mean measurement). Measurements of the brachium, crus, and thigh typically had poor inter- and intratester reliability, ICC < 0.5. CONCLUSION Using the described method of muscle measurement in Labrador Retrievers only measurement of the proximal antebrachium was reliable; a single (1st) measurement was as reliable as using the mean of triplicate measurements.

Primary synovial osteochondromatosis of the stifle in an English Mastiff

A two-year-old, 97 kg, male neutered English Mastiff was evaluated for left pelvic limb lameness of five months duration localized to the stifle joint. Following radiographic, computed tomographic and arthroscopic examination, the lameness was subsequently diagnosed as being caused by primary synovial osteochondromatosis. In total, 194 osteochondral bodies were removed using arthroscopy in combination with a mini-arthrotomy. Histology and immunohistochemistry of the loose osteochondral fragments confirmed the diagnosis with a moderately high degree of differentiation and low cellularity. Nuclear staining for Ki-67 revealed decreasing differentiation and increasing cellularity in the fragments. At the 13 months telephone follow-up the owner reported that the dog was free from lameness and had a vastly improved function compared with preoperative levels, although mild lameness did occasionally occur. This is the first report of computed tomography, arthroscopy and immunohistochemistry confirming a case of primary synovial osteochondromatosis in a dog.