Intermandibular malignant mesenchymoma in a crossbreed dog.

A 12-year-old German shepherd crossbreed dog was presented with a submandibular mass that was initially diagnosed as myxosarcoma on incisional biopsy. Chest radiographs were taken for staging, and magnetic resonance imaging was performed to assess the feasibility of cytoreductive surgery before adjuvant radiotherapy. The dog underwent debulking surgery, and histology permitted reclassification of the tumour as a malignant mesenchymoma (with myxosarcomatous and osteosarcomatous differentiation). The dog was subsequently treated with four fractions of radiotherapy given at seven-day intervals and three doses of carboplatin. The dog remained stable following therapy until its condition acutely deteriorated, and it was euthanased 153 days after surgery. On postmortem examination, there were no signs of local tumour recurrence, but metastases were observed both in the thorax and in the abdomen.

Role of carboplatin in multi-modality treatment of canine tonsillar squamous cell carcinoma--a case series of five dogs.

Canine tonsillar squamous cell carcinoma is an aggressive disease with a poor prognosis. A retrospective study was undertaken of all dogs that were presented between January 1999 and January 2004 to the Animal Health Trust for the treatment of tonsillar squamous cell carcinoma. Five cases were identified, and their median survival time was 211 days (95 per cent confidence interval 80 to 352) with two of the five dogs remaining alive at the end of the study, 826 and 1628 days from diagnosis with no clinical signs of disease. The protocol was well tolerated with only one of the five dogs showing toxicity associated with carboplatin and all dogs that started radiotherapy completing it. Compared with results of previous studies, these cases suggest that surgical cytoreduction followed by coarse fractionated radiotherapy together with carboplatin may be a useful way to treat this tumour. Carboplatin alone caused partial remission in the two cases where it was used as neo-adjunctive therapy.

Lung lobe torsion in dogs: 22 cases (1981-1999).

OBJECTIVE: To identify breed disposition, postoperative complications, and outcome in dogs with lung lobe torsion. DESIGN: Retrospective study. ANIMALS: 22 client-owned dogs. PROCEDURE: Information on signalment; history; clinical findings; results of clinicopathologic testing, diagnostic imaging, and pleural fluid analysis; surgical treatment; intra- and postoperative complications; histologic findings; and outcome were obtained from medical records. RESULTS: All 22 dogs had pleural effusion; dyspnea was the most common reason for examination. Fifteen dogs were large deep-chested breeds; 5 were toy breeds. Afghan Hounds were overrepresented, compared with the hospital population. One dog was euthanatized without treatment; the remaining dogs underwent exploratory thoracotomy and lung lobectomy. Eleven dogs recovered from surgery without complications, but 3 of these later died of thoracic disease. Four dogs survived to discharge but had clinically important complications within 2 months, including chylothorax, mediastinal mesothelioma, gastric dilatation, and a second lung lobe torsion. Six dogs died or were euthanatized within 2 weeks after surgery because of acute respiratory distress syndrome, pneumonia, septic shock, pneumothorax, or chylothorax. Chylothorax was diagnosed in 8 of the 22 dogs, including 4 Afghan Hounds. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggest that lung lobe torsion is rare in dogs and develops most frequently in large deep-chested dogs, particularly Afghan Hounds. Other predisposing causes were not identified, but an association with chylothorax was evident, especially in Afghan Hounds. Prognosis for dogs with lung lobe torsion was fair to guarded.

The hemodynamic effects of intrathecal oxytocin in normal dogs.

OBJECTIVE: To evaluate the hemodynamic effects produced by intrathecal administration of oxytocin in healthy isoflurane-anesthetized dogs. STUDY DESIGN: Prospective single-dose trial. ANIMAL POPULATION: Six healthy purpose-bred adult dogs weighing between 7.3 and 14.5 kg. METHODS: Dogs were anesthetized with isoflurane and instrumented. Oxytocin at a dosage of 1.6 microg/kg was administered intrathecally at the cisternal space at time 0. Hemodynamic data were recorded immediately before and at 1, 5, 15, 30, and 60 minutes after oxytocin administration. Statistical analysis included an analysis of variance (ANOVA) for repeated measures over time. A P < .05 was considered significant. RESULTS: Baseline values +/- standard error of the mean for heart rate, mean arterial pressure, central venous pressure, cardiac output, systemic vascular resistance, mean pulmonary arterial pressure, pulmonary arterial occlusion pressure, and pulmonary vascular resistance were 101 +/- 11 beats/minute, 76 +/- 7 mm Hg, 4 +/- 4 mm Hg, 1.9 +/- 0.7 L/min, 3834 +/- 2556 dynes x sec/cm5, 14 +/- 3 mm Hg, 4 +/- 2 mm Hg, and 430 +/- 201 dynes x sec/cm5, respectively. Variations from the baseline values were seen in all parameters after intrathecal oxytocin administration, but no statistically significant differences were found. CONCLUSION: The intrathecal injection of 1.6 microg/kg of oxytocin is associated with minimal hemodynamic effects during isoflurane anesthesia. CLINICAL RELEVANCE: This study revealed no clinically significant deleterious effects from the intrathecal administration of oxytocin, and investigations into its use as a perioperative analgesic are therefore warranted.

B-mode and Doppler ultrasound imaging of the spleen with canine splenic torsion: a retrospective evaluation.

The ultrasonographic appearance of splenic torsion has been described; the splenic parenchyma can be normal, hypoechoic or anechoic with interspersed linear echoes (coarse/"lacy" appearance). The ultrasonographic parenchymal appearance of 15 dogs in this report with splenic torsion varied: mottled hypoechoic regions (n=2), diffusely hypoechoic (n=11) and normal (n=2). Because splenic torsion causes vascular congestion due to splenic vein compression and eventual thrombosis, visible splenic vein intraluminal echogenicities compatible with thrombi were seen in 13 dogs using B-mode. Using spectral Doppler and color Doppler imaging of the splenic veins, no measurable flow velocities were detected in any of the 15 dogs. The varied B-mode ultrasonographic appearance of the splenic parenchyma with splenic torsion necessitates B-mode evaluation of the splenic veins for intraluminal echoes and spectral or color Doppler evaluation for absent velocity flow.

Retrospective analysis of 19 cases of isolated torsion of the splenic pedicle in dogs.

Nineteen cases of isolated splenic torsion in the dog were reviewed retrospectively. Perioperative data were analysed in order to determine prognostic indicators of morbidity and mortality for animals with this disease. This Great Dane and German shepherd dog were found to be at increased risk for this condition. The historical features of splenic torsion were non-specific and included intermittent signs of gastrointestinal disease and abdominal discomfort. Mean duration of malaise was eight days, but 17 dogs were presented because of a rapid deterioration in their condition. Abdominal ultrasound findings assisted in the decision to perform surgery in all the dogs on which it was performed. Eighteen animals had splenic torsion confirmed at surgery and were treated by total splenectomy. All 18 surgically managed dogs survived. Analysis of pre- and postoperative data failed to reveal preoperative parameters that consistently predicted postoperative complications.

Intraocular pressure-dependent and -independent phases of growth of the embryonic chick eye and cornea.

The pattern and relative rates of diametric growth of the avian eye and cornea are described throughout embryonic development. The effect of reduced intraocular pressure on eye and corneal diametric growth also was investigated. Between embryonic day 4 (E4) and 1 day posthatching, the eye undergoes two distinct phases of linear growth. The first phase (E4-10) is very rapid (1.193 mm/day). The second phase, after E10, is significantly slower (0.346 mm/day). By contrast, over the same developmental period, the cornea undergoes three distinct and sequential phases of linear growth. The second phase of corneal growth (E7-10) is the most rapid (0.429 mm/day) and separates two periods of slow growth (0.211 mm/day during E4-7 and 0.128 mm/day after E10). After the sustained release of intraocular pressure by intubation on E4, growth of both the eye and cornea is reduced significantly. Operated eyes grow at a rate of 0.356 mm/day (E4-10) and 0.155 mm/day (E10-16). Intubation reduces corneal growth to a single phase of 0.125 mm/day (E7-16). Thus, from E4-10 both the eye and cornea possess intrinsic growth potentials that are elevated significantly by intraocular pressure. After E10, the rate of growth of both the eye and the cornea is independent of intraocular pressure. Because both control and intubated eyes change their growth rate on E10, this transition also is independent of intraocular pressure. This contrasts with the cornea which, after intubation, shows no detectable variation in growth rate. Correlation of eye with corneal growth demonstrates an exponential relationship in the presence of intraocular pressure and an almost linear relationship after intubation.