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Objective: To determine the effect of WBC accumulation on the concentration of enrofloxacin in inflamed tissues in dogs., Animals: 6 adult Bloodhounds., Procedures: Dogs were instrumented bilaterally with tissue chambers. Peripheral WBCs collected from each dog were exposed in vitro to radiolabeled enrofloxacin ((14)C-ENR). Inflammation was induced with carrageenan in 1 chamber. Ten hours later, treated cells were administered IV to each dog such that (14)C-ENR was delivered at a mean +/- SD dosage of 212 +/- 43 microg. Samples of extracellular fluid from inflammation and control chambers and circulating blood were then collected before (baseline) and for 24 hours after WBCs were administered. Samples were centrifuged to separate WBCs from plasma (blood) or chamber fluid. Radiolabeled enrofloxacin was scintigraphically detected and pharmacokinetically analyzed. Comparisons were made between extra- and intracellular chamber fluids by use of a Student paired t test., Results: (14)C-ENR was not detectable in plasma, peripheral WBCs, control chambers, or baseline samples from inflammation chambers. However, (14)C-ENR was detected in extra- cellular fluid from inflammation chambers (mean +/- SD maximum concentration, 2.3 +/- 0.5 ng/mL) and WBCs (maximum concentration, 7.7 +/- 1.9 ng/mL). Mean disappearance half-life of (14)C-ENR from extracellular fluid and WBCs from inflammation chambers was 26 +/- 10 hours and 17 +/- 6 hours, respectively., Conclusions and Clinical Relevance: WBCs were responsible for the transport and release of (14)C-ENR at sites of inflammation. Accumulation of drug by WBCs might increase the concentration of drug at the site of infection, thus facilitating therapeutic success.

Concentrations of enrofloxacin and its active metabolite, ciprofloxacin, were detected in tissues following single intravenous administration of 20 mg/kg to four anesthetized dogs. Two hours after treatment, serum samples were collected, animals were euthanized, and tissues were collected from each dog. Solid tissues were homogenized, and both enrofloxacin and ciprofloxacin were detected using high-performance liquid chromatography. Enrofloxacin was detected in all tissues examined; the highest concentrations were found in the gall bladder, urine, bile, stomach, and liver. Concentrations in the cerebral cortex, cerebrospinal fluid, skin, and prostate were 5.7, 5.3, 9.2, and 23.5 microg/ml, respectively. Tissues for which the concentration of enrofloxacin was 4 microg/ml or lower included the trachea, articular cartilage, aqueous humor, fat, and tendon. An inhibitory quotient of 8 or more was achieved for enrofloxacin in the majority of tissues studied. Ciprofloxacin was detected in 29 of 40 tissues examined.

Objective: To determine long-term results and complications of gonadectomy performed at an early age (prepubertal) or at the traditional age in dogs., Design: Cohort study., Animals: 269 dogs from animal shelters., Procedure: Dogs that underwent gonadectomy were allotted to 2 groups on the basis of estimated age at surgery (traditional age, > or =24 weeks old; prepubertal, < 24 weeks old). Adoptive owner information was obtained from shelter records, and telephone interviews were conducted with owners to determine physical or behavioral problems observed in the dogs since adoption. Follow-up information was obtained from attending veterinarians for dogs with complex problems or when owners were uncertain regarding the exact nature of their dog's problem., Results: Prepubertal gonadectomy did not result in an increased incidence of behavioral problems or problems associated with any body system, compared with traditional-age gonadectomy, during a median follow-up period of 48 months after gonadectomy. Rate of retention in the original adoptive household was the same for dogs that underwent prepubertal gonadectomy as those that underwent traditional-age gonadectomy. Infectious diseases, however, were more common in dogs that underwent prepubertal gonadectomy., Conclusions and Clinical Implications: With the exception of infectious diseases, prepubertal gonadectomy may be safely performed in dogs without concern for increased incidence of physical or behavioral problems during at least a 4-year period after gonadectomy.

Urethral injuries are relatively common in male dogs and cats. Urethral epithelium has impressive regenerative properties, and healing by second intention is effective as long as there is mucosal continuity across the traumatized area. Principles of managing traumatic urethral injuries include an accurate patient assessment, including a determination of the extent of the urethral injury; correction of electrolyte or acid-base disturbances; provision of urinary diversion, particularly with pelvic or perineal urethral defects; drainage of extravasated urine; and selection of a surgical procedure to repair or bypass the injured portion of urethra. Treatment options include temporary urinary diversion through cystostomy or urethral catheterization and second intention healing, permanent bypassing of the traumatized area through urethrostomy proximal to the injury site, and primary repair of transection injuries. The scrotal site is the most frequently used and preferred site for urethrostomy in the male dog to bypass the injured penile urethra. Urethral surgery necessitates care and attentiveness to detail, considering that accurate approximation of urethral mucosa minimizes fibrosis and helps maintain an adequate luminal diameter. Avoidance of stricture and preservation of function are goals of managing traumatic urethral injuries.

This study compared three methods of pain relief in dogs that had total ear canal ablation with lateral bulla osteotomy. The hypothesis was that systemic opioids with preoperative local nerve blocks would provide superior pain relief. Thirty-one dogs with chronic otitis externa were included in the study. Dogs were randomly assigned to one of three protocols: systemic opioids alone (10 dogs, group 1), systemic opioids with bupivacaine splash block (11 dogs, group 2), and systemic opioids with preoperative local bupivacaine nerve blocks (10 dogs, group 3). Twenty-one dogs had bilateral ear ablation and 10 had unilateral ablation. Pain was assessed preoperatively, at extubation, 2 hours postextubation, and 1 day postoperatively by a single observer blinded to the analgesic protocol used. Pain scores were not significantly different within or between groups, nor did unilateral versus bilateral ablation have a significant effect on the score. Mean scores were less than 3 (scale 1 to 5) for all groups at all observation times. Rough recoveries were noted in 30% of group 1 dogs, 0% of group 2, and 20% of group 3 dogs. Ninety-four percent of dogs were moderately to heavily sedated at extubation. Sixty percent of group 3 dogs remained moderately to heavily sedated 2 hours postextubation. Rectal temperature, pulse rate, respiratory rate, and postoperative change in serum cortisol levels were not significantly different between groups. Postoperative increase in blood glucose was significantly higher in groups 1 and 3 compared with preoperative levels. Twenty-three percent of the dogs required additional analgesia or tranquilization after surgery, as determined by the anesthetist; 1 dog in group 1, 2 in group 2, and 4 in group 3. Each of the three analgesic protocols provided similar pain relief in dogs undergoing total ear canal ablation.

Five dogs were diagnosed as having unilateral separation of the otic cartilages (auricular and annular). Four dogs had sustained prior trauma (hit by a car). Clinical signs were typical of ear canal stenosis and included swelling at the base of the ear (n = 2), periotic fistulation (n = 2), head tilt toward the affected side (n = 2), and pain when opening the mouth (n = 1). Palpation revealed separation of the horizontal and vertical ear canals. Otoscopic findings included a shallow ear canal and a pseudotympanic membrane across the proximal end of the auricular cartilage. Findings at surgery confirmed the diagnosis of cartilage separation and included an exudate-filled horizontal ear canal and a blind-ending vertical ear canal. Surgical treatment involved isolating the distal end of the annular cartilage (horizontal ear canal), opening and evacuating the horizontal ear canal, and suturing the open end of the annular cartilage to the skin. The length of annular cartilage was variable among the dogs, although each dog had sufficient horizontal canal to appose skin to otic epithelium. The vertical ear canal was not surgically dissected or manipulated. The mean follow-up period was 46 +/- 14 months (range, 31 to 68 months). All five dogs had patent horizontal ear canals when examined at the follow-up examination.

Objective: To describe the long-term outcome in dogs with naturally developing multiple extrahepatic portosystemic shunts (PSS)., Design: Retrospective case series., Animals: 30 dogs with multiple PSS., Procedure: Medical records of dogs with multiple PSS were reviewed. Follow-up data were obtained by 1 or more of the following methods: recheck at the veterinary teaching hospital (n = 6) or telephone contact with the referring veterinarian (n = 18) or owner (n = 10). The chi 2 or Mann-Whitney rank sum test was used to determine the association of clinical factors with long-term outcome. Survival curves were generated by the Kaplan-Meier product limit method., Results: Median age at diagnosis was 1 year. Findings on exploratory surgery in 25 dogs included ascites; numerous tortuous vessels connecting the portal vein with systemic veins; a small, misshapen liver; and an enlarged portal vein. The most common lesions on histologic evaluation of hepatic tissue specimens were hepatocellular atrophy, portal vascular duplication, cirrhosis, inflammation, and bile duct proliferation. Twelve dogs were treated surgically with vena caval banding, whereas 13 dogs were treated conservatively with dietary restriction of protein and administration of antibiotics, diuretics, and other drugs. Long-term survival and quality of life were similar in dogs from both treatment groups. Median follow-up interval in dogs that survived hospitalization was 24 months (range, 1 to 54 months)., Clinical Implications: On the basis of these findings, vena caval banding in dogs with multiple PSS is not superior to medical and nutritional treatment.

To measure tracheal mucociliary transport rate (TMTR) in awake dogs, restrained in dorsal recumbency, 99mtechnetium-labeled macroaggregated albumin was administered by tracheal injection, and the cephalic movement of boluses containing the radiopharmaceutical was detected by a gamma camera positioned lateral to the dog's head and neck. The distance traveled by each bolus was measured, relative to external markers placed a known distance apart. Tracheal mucociliary transport rates were calculated by dividing the measured distance of radiopharmaceutical movement by elapsed time. The technique was efficient and well tolerated. Mean (+/- SD) TMTR was 35.3 +/- 15.9 mm/min. Significant (P = 0.029) difference in TMTR was found between males and females, but significant difference attributable to age of the dog was not detected. This method of measuring TMTR in awake dogs has potential for evaluation of clinical animal patients with suspected tracheal mucociliary abnormalities.

Comparison was made of the healing of sutured prescrotal urethral incisions (12 dogs) with that of nonsutured incisions (6 dogs). Comparison was also made of the healing of 5-0 polyglactin 910-sutured urethral incisions (6 dogs) with that of 5-0 polydioxanone-sutured incisions (6 dogs). Three dogs from each treatment group were euthanatized 3 weeks and 6 weeks after the surgical procedure. Surgical sites were examined grossly, and urethral circumference measurements were taken at 3 locations (surgical site, 1 cm cranially, and 1 cm caudally). Transverse sections of the surgical sites were prepared and examined by light microscopy. Hemorrhage occurred postoperatively in dogs in which the incisions were not sutured. The surgical sites from the 6 dogs in which incisions healed by second intention had more fibrosis and less inflammation than did those that were sutured. There was little difference between incisions sutured with polyglactin 910 and those sutured with polydioxanone suture material. Postoperative urethral stricture formation did not occur in any of the dogs.

Twenty-three canine pelves were tested bilaterally to determine the stiffness and strength of intact ilium and stabilized oblique iliac osteotomies that simulated a common clinical fracture. Fixation systems tested were three 4.0 mm cancellous screws inserted ventral to dorsal across the osteotomy site and one laterally placed five hole 3.5 mm dynamic compression plate. Specimens were mechanically tested to failure under torsional, axial, or axial plus bending loads. Lag screw fixation was stiffer and stronger than plate fixation in all testing modes. The differences were statistically significant (p less than .05) in the torsional and axial plus bending loading modes. Fatigue testing was performed on implanted specimens with low-level cyclic loading under axial plus bending loading conditions. Physiologic loading conditions failed to produce mechanical failure of either fixation system after 100,000 cycles.

Biomechanical analysis was performed on the cranial cruciate ligament (CCL) and three autogenous tissues used for CCL reconstruction in the canine stifle. The autogenous tissues were patellar ligament-based autografts described for over-the-top CCL replacement and included the central one third of the patellar ligament, the medial one third of the patellar ligament, and the lateral one third of the patellar ligament with fascia lata. Tension testing produced abrupt failure of the central and medial autografts but sequential failure of the lateral autograft. Structural properties were determined for the overload condition and within the load range of normal activity for the CCL (physiologic range). None of the autograft systems approached the stiffness, maximum load, and energy absorbed to maximum load of the CCL. The central and lateral autografts were stiffer, had greater maximum loads, and absorbed more energy to maximum load than the medial autograft. The central and lateral autografts had an elastic range, as defined by proportional limit, which corresponded to the physiologic range of loading for the CCL. Loads that corresponded to physiologic displacement of the lateral and central autografts were near the maximum load of the fixation site, which underscored the need for postoperative support of the repaired stifle.