Evaluation of the Palmaz Stent in the Trachea and Mainstem Bronchi of Normal Dogs

Objective — This study evaluates the efficacy of the Palmaz balloon expandable intraluminal stent in the trachea and mainstem bronchi of normal dogs. Study Design — Effects of the stent were evaluated by physical examination, thoracic radiography, respiratory tract fluoroscopy and endoscopy, tracheal diameter measurement, postmortem examination, and airway histomorphometry. Animals or Sample Population — Ten normal beagle dogs. Methods — Stent size was estimated from thoracic radiographs in awake dogs. Group I dogs (n = 4) had two stents placed: one in the thoracic trachea (TT) plus a randomly chosen mainstem bronchus (MB). Group II dogs (n = 3) had stents placed in the MB (one stent), TT (one stent), and mid- or proximal cervical trachea (CT) (one or two stents). Three dogs were used as sham-operated controls (group III). Temperature, pulse, respiration, and cough were measured twice daily. Dogs were evaluated at 21 and 49 to 56 days after stent placement, euthanatized, and tissues were collected for histomorphometric analysis of stent integration and epithelial pathology. Results — Mean tracheal diameters of awake (10.5 ±1.7 mm) and anesthetized dogs before stent implantation (13.9 ± 2.0 mm) were significantly different (P <.01). Complications associated with stent placement included acute pulmonary edema (n = 2), stent migration (n = 7), stent collapse (n = 4 CT, 2 TT, and 1 MB), and positive tracheal culture (n = 10). Group II dogs coughed more at rest, exercise, and with tracheal palpation than dogs in other groups (P <.01). Group I dogs coughed more at rest than group III dogs (P <.01). Stent integration ranged from 0 to 91.3%. Squamous metaplasia and epithelial ulceration associated with stents ranged from 0 to 57.5% and 0 to 32.7%, respectively. Conclusions — Determination of stent size should be based on measurements taken on anesthetized dogs because use of inappropriately sized stents may promote stent migration, squamous metaplasia, and/or ulceration. Epithelialization over stent struts may occur if the stent is closely associated with tracheal epithelium. Clinical Relevance — Palmaz stents do not appear to be appropriate for placement in the CT of dogs; however, with technical modifications, application in the TT and MB may be feasible.     

Squamous cell carcinoma of the middle ear in a cat

Squamous cell carcinoma of the middle ear and tympanic bulla was diagnosed in a 13-year-old cat. This is the first report of squamous cell carcinoma in this location in a cat.     

Inflammatory polypoid growths in the ear canal of cats

The characteristic clinical and pathological features of polyps of the ear canal as seen in 12 cats at the University of Pennsylvania Veterinary Hospital are described. In the authors' experience, and contrary to previous reports, inflammatory polyps are the commonest tumour of the feline ear and can be differentiated clinically from other neoplasms.     

DOSIMETRIC IMPACT OF DAILY SETUP VARIATIONS DURING TREATMENT OF CANINE NASAL TUMORS USING INTENSITY-MODULATED RADIATION THERAPY

Intensity-modulated radiation therapy (IMRT) can be employed to yield precise dose distributions that tightly conform to targets and reduce high doses to normal structures by generating steep dose gradients. Because of these sharp gradients, daily setup variations may have an adverse effect on clinical outcome such that an adjacent normal structure may be overdosed and/or the target may be underdosed. This study provides a detailed analysis of the impact of daily setup variations on optimized IMRT canine nasal tumor treatment plans when variations are not accounted for due to the lack of image guidance. Setup histories of ten patients with nasal tumors previously treated using helical tomotherapy were replanned retrospectively to study the impact of daily setup variations on IMRT dose distributions. Daily setup shifts were applied to IMRT plans on a fraction-by-fraction basis. Using mattress immobilization and laser alignment, mean setup error magnitude in any single dimension was at least 2.5 mm (0–10.0 mm). With inclusions of all three translational coordinates, mean composite offset vector was 5.9±3.3 mm. Due to variations, a loss of equivalent uniform dose for target volumes of up to 5.6% was noted which corresponded to a potential loss in tumor control probability of 39.5%. Overdosing of eyes and brain was noted by increases in mean normalized total dose and highest normalized dose given to 2% of the volume. Findings suggest that successful implementation of canine nasal IMRT requires daily image guidance to ensure accurate delivery of precise IMRT distributions when non-rigid immobilization techniques are utilized. Unrecognized geographical misses may result in tumor recurrence and/or radiation toxicities to the eyes and brain.     

Fine‐scale movements of the swordfish Xiphias gladius in the Southern California Bight

This study reports on the fine‐scale movements of swordfish (Xiphias gladius) outfitted with pop‐off satellite archival transmitters (PSATs) in the Southern California Bight (SCB). PSATs were deployed on basking swordfish using traditional harpoon methods from 2004 to 2006. Transmitters were programmed for short‐term deployment (2–90 days) and re‐acquired using a signal direction finder. High‐resolution (min^?1) depth and temperature data from nine swordfish (approximately 45–120 kg) were collected (>193 days). All swordfish displayed diurnal vertical movements similar to those reported for other geographic locations. The dominant diurnal movement pattern entailed swordfish remaining below the thermocline (>68 ± 15 m) during the day and near the surface, within the upper‐mixed layer, at night. Collectively, the average daytime depth (±SE) was 273 ± 11 m and the average night depth 31 ± 5 m. Three distinct vertical behaviors were recorded: 35% of the records following a strict diurnal pattern, with the entire day below the thermocline and the entire night near the surface; 52% of the records revealed routine surface‐basking events during the day, with an otherwise similar distribution at night; and 13% of the records exhibited surface‐oriented activity during the day and night. Surface basking (<3 m during the day) was recorded for eight individuals and occurred on 131 of the 193 days (68% of the dataset). Collectively, surface basking accounted for 8% of the total daytime records. The relevance of these vertical behaviors to SCB fisheries is discussed.     

Loss of benthic communities: warning signal for coastal ecosystem management

1. Marine managers deal predominantly with shallow coastal waters. These are among the most economically valuable, biologically diverse, and endangered marine ecosystems. 2. Major changes in the composition of biological communities in such shallow seas should be cause for alarm. Changes in the benthic subsystem may provide more information than those in the pelagic subsystem because such changes on the seafloor tend to be more long-term. 3. In the northern Adriatic Sea, soft bottom communities have been subject to a recent series of dramatic mortalities due to oxygen deficiency (accompanied by marine snow events and a series of anthropogenic impacts). The affected areas measure hundreds to thousands of square kilometres. 4. We document this deterioration based on the two major components of soft bottom communities (the endo- and epibenthos), specifically on a key endobenthic species (the sea urchin Schizaster canaliferus) and on a characteristic epibenthic filter-feeding community. 5. The high frequency of disturbances, coupled with lengthy recovery periods, indicate a long-term destabilization of the entire ecosystem. 6. Coastal managers must be aware of the significance of such ecological shifts; biological data should form the basis for policy- and decision-making processes. ©1996 by John Wiley & Sons, Ltd.     

Traumatic Coxofemoral Luxation In Dogs Results of Repair

The medical records of 171 dogs with traumatic hip luxations were examined. German shepherds, mixed breeds, and poodles were significantly overrepresented. The mean age of the patients at the time of diagnosis was 4.4 years (range 5 months to 14 years). Vehicular trauma caused 83% of the 133 luxations where the etiology was known; 53% had at least one other diagnosed traumatic injury. Long-term results were obtained from owner questionnaires (25 dogs) or clinical and radiographic examinations (11 hip joints). The short-term recurrence rate after closed reduction (47.3%) was higher than that after surgical reduction using any of the three surgical techniques most frequently used here (9.5, 12.5, and 14.3%), even when the operation was performed after failure of a closed reduction (11.8%). Excluding dogs that had a femoral head ostectomy, 68% (17 of 25) of the dogs had a normal gait, 16% had only a mild lameness, and 16% had more severe lameness when evaluated on an average of 31 months after repair. Of 11 hip joints radiographed on an average of 25 months following repair, five had no radio-graphic abnormalities related to the luxation and six showed one or more of the following: periosteal new bone formation, femoral head subluxation, partial resorption of the femoral head, periarticular osteophytes, and subchondral bone erosion. Closed reduction should be the initial treatment of choice in uncomplicated luxations even though the rate of reluxation is high, because it avoids the need for surgery in approximately one half of affected dogs and does not increase the recurrence rate following subsequent surgical reduction.     

Axial Pattern Flap Based on the Superficial Brachial Artery in the Dog

An axial pattern flap based on the superficial brachial artery and vein (brachial axial pattern flap) was developed on the forelimbs of five dogs. The flap was immediately transferred to a distal cutaneous defect created on the antebrachium of that limb. A control flap was elevated on the opposite limb and transferred to a similar distal site after ligation of the superficial brachial artery and vein at the base of the flap. Mean brachial axial pattern flap survival (98%) was significantly more than mean control flap survival (77%) (p less than 0.05). Results of this study suggest that the brachial axial pattern flap has potential application for closure of major cutaneous defects involving the canine antebrachium above the carpus.     

Partial Gastrectomy with an Automatic Stapling Instrument for Treatment of Gastric Necrosis Secondary to Gastric Dilatation-Volvulus

A gastrointestinal anastomosis stapling instrument was used to perform partial gastrectomy in nine dogs undergoing emergency surgery for gastric dilatation-volvulus. The amount of necrotic stomach resected was 20% to 50%. Permanent gastropexy was performed, and six dogs also required partial or total splenectomy. Six dogs (67%) were normal after surgery, with follow-up periods of 6 to 16 months for five dogs. One dog died and two dogs were euthanatized because of postoperative complications unrelated to the surgical technique. There were no complications involving the partial gastrectomy staple line.     

Suspensory Apparatus Prosthesis in the Horse Part 2: In Vivo Evaluation in a Suspensory Apparatus Disruption Model

The suspensory apparatus of one forelimb was surgically disrupted in six adult horses by transecting the distal sesamoidean ligaments. A double-braided prosthetic ligament made of aramid yarn was installed to support the flexor surface of the metacarpophalangeal joint. The prosthesis was routed through tunnels in the third metacarpal bone and proximal phalanx, and secured to bone with screws. Evaluation by radiography, synovial fluid analysis, cinematography, and dynamography was performed before surgery and at weeks 16 and 30. Supracondylar cortical lysis and periosteal proliferation were observed on postoperative radiographs. Synovitis and fragmentation of the prosthesis were apparent from synovial fluid evaluation. Weight bearing and metacarpophalangeal joint motion were decreased and loading was transferred in part to the opposite forelimb. Clinical lameness improved and weight bearing increased during the second half of the 30-week period. At necropsy, there was abrasion of the prosthesis and the articular surfaces in contact with the prosthesis. Diffuse granulomatous synovitis developed in response to aramid fiber fragments within the synovium.