Postmortem evaluation of surgery site leakage by use of in situ isolated pulsatile perfusion after partial liver lobectomy in dogs.

OBJECTIVE: To evaluate postmortem surgery site leakage by use of in situ isolated pulsatile perfusion after partial liver lobectomies. ANIMALS: 10 healthy mixed-breed male dogs. PROCEDURES: Dogs were anesthetized, and 5 surgical techniques (pretied suture loop, energy-based sealer-divider, harmonic scalpel, suction with clip application, or suction with use of a thoracoabdominal stapler) were used to perform 5 partial liver lobectomies in each dog. Dogs were euthanatized, and the portal vein and hepatic artery were cannulated and perfused with a modified kidney perfusion machine (pulsatile flow for arterial perfusion and nonpulsatile flow for portal perfusion). Lobectomy sites were inspected for leakage of perfusate, and time until detection of leakage was recorded. The techniques in each dog were ranked on the basis of time until leakage. Time until leakage and rankings for each surgical technique were analyzed by use of an ANOVA. RESULTS: Leakage of perfusate was recorded in 44 lobes at supraphysiologic pressures. Of the 6 lobes without leakage, a pretied suture loop procedure was performed in 5 and a harmonic scalpel procedure was performed in 1. Time until leakage and the ranking differed significantly between the pretied suture loop and the other techniques. Time until leakage and ranking did not differ significantly among the other techniques. CONCLUSIONS AND CLINICAL RELEVANCE: Time until leakage of perfusate was greater for the pretied suture loop technique than for the other techniques, and that technique did not fail in 5 of 10 lobes. However, all techniques appeared to be safe for clinical use.

Biomechanical and histologic comparison of single-layer continuous Cushing and simple continuous appositional cystotomy closure by use of poliglecaprone 25 in rats with experimentally induced inflammation of the urinary bladder.

OBJECTIVE: To biomechanically and histologically compare single-layer continuous Cushing and simple continuous appositional cystotomy closure in rats with xylene-induced cystitis. ANIMALS: 40 female Sprague-Dawley rats. PROCEDURE: Rats were anesthetized, their urinary bladders catheterized and evacuated, and xylene instilled in each bladder for 5 minutes and then aspirated. Forty-eight hours later, ventral midline celiotomy and cystotomy (8 mm) were performed. Cystotomies were closed with 6-0 poliglecaprone 25 by use of a single-layer continuous Cushing or simple continuous appositional pattern (20 rats/group), and cystotomy times were recorded. Rats were allocated to healing durations (5 rats/group) of 0, 3, 7, and 14 days. Celiotomies were closed in a routine manner. After the allotted healing interval, another celiotomy was performed, the urethra cannulated, and ureters ligated. The cannula was secured to the urethra, and the bladder infused at 0.1 mL/min. Leak pressure volume, leak pressure, peak pressure volume, and peak pressure were recorded via a pressure transducer. Bladders were harvested and histologically assessed. RESULTS: Cystotomy time, biomechanical testing values, and overall inflammation scores did not differ between closure methods for any healing duration. Both methods had significantly greater leak pressures, with the appositional method also having significantly greater peak pressures on day 7, compared to day 0. Biomechanical testing values decreased from day 7 to 14 as a result of juxtaincisional weakening of the bladder and xylene-induced changes in collagen. CONCLUSIONS AND CLINICAL RELEVANCE: Simple continuous appositional was equal biomechanically and histologically to continuous Cushing for all comparison variables. Poliglecaprone 25 was acceptable for cystotomy closure.

Investigation of the effect of pamidronate disodium on the in vitro viability of osteosarcoma cells from dogs.

OBJECTIVE: To determine the effect of pamidronate disodium on the in vitro viability of osteosarcoma cells and non-neoplastic cells from dogs. SAMPLE POPULATION: 3 osteosarcoma and 1 fibroblast cell lines derived from dogs. PROCEDURE: Cell counts and cell viability assays were performed in cultures of osteosarcoma cells (POS, HMPOS, and COS31 cell lines) and fibroblasts after 24, 48, and 72 hours of incubation with pamidronate at concentrations of 0.001 to 1000 microM or with no drug (control treatment). Percentage viability was determined in cell samples for each concentration of pamidronate and each incubation time. A DNA fragmentation analysis was performed to assess bisphosphonate-induced apoptosis. RESULTS: Osteosarcoma cell viability decreased significantly in a concentration- and time-dependent manner at pamidronate concentrations ranging from 100 to 1000 microM, most consistently after 48 and 72 hours' exposure. In treated osteosarcoma cells, the lowest percentage cell viability was 34% (detected after 72 hours' exposure to 1000 microM pamidronate). Conversely, 72 hours' exposure to 1000 microM pamidronate did not significantly reduce fibroblast viability (the lowest percentage viability was 76%). After 72 hours of exposure, pamidronate did not cause DNA fragmentation in POS or HMPOS cells. CONCLUSIONS AND CLINICAL RELEVANCE: Results indicate that pamidronate may have the potential to inhibit osteosarcoma growth in dogs, possibly through a nonapoptotic mechanism. The clinical relevance of these in vitro findings remains to be determined, but administration of pamidronate may potentially be indicated as an adjuvant treatment in chemotherapeutic protocols used in dogs.

Evaluation of oxidative stress markers for the early diagnosis of allograft rejection in feline renal allotransplant recipients with normal renal function.

The purpose of this study was to identify oxidative damage to renal allografts during graft rejection by evaluating changes in oxidative markers and plasma lactate levels in feline renal allotransplant recipients. Heterotopic renal allotransplantations were performed between 8 adult feline cross-matched donors. Following 14 d of immunosuppression, the drugs were discontinued to allow allograft rejection. Baseline and serial postoperative evaluations of serum creatinine, plasma lactate, plasma thiobarbituate reactive substances (TBARS), plasma creatol, urine creatol, and renal sonographic cross-sectional area were performed. When sonographic evaluation revealed the absence of blood flow to the allograft, the rejected kidney was nephrectomized and evaluated histopathologically. Allograft rejection occurred in all cats by day 26. A significant elevation in body temperature occurred during the rejection period. No significant change was observed between any of the time periods for plasma TBARS, creatol, or urine creatol. There was a significant decrease in plasma lactate levels throughout the study. Markers of oxidative stress from venous blood did not reflect renal allograft rejection in cats with a normally functioning native kidney. Renal allograft rejection may be associated with significant increases in body temperature and warrants further investigation.

Effect of thalidomide on growth and metastasis of canine osteosarcoma cells after xenotransplantation in athymic mice.

OBJECTIVE: To determine whether thalidomide inhibits the growth of primary and pulmonary metastatic canine osteosarcoma in mice after xenotransplantation. ANIMALS: Athymic nude mice. PROCEDURE: Canine osteosarcoma cells were injected SC in 50 mice. Mice were randomly placed into the following groups: control group (n = 13; DMSO [drug vehicle] alone [0.1 mL/d, IP]); low-dose group (12; thalidomide [100 mg/kg, IP]), mid-dose group (13; thalidomide [200 mg/kg, IP]); and high-dose group (12; thalidomide [400 mg/kg, IP]). Starting on day 8, treatments were administered daily and tumor measurements were performed for 20 days. On day 28, mice were euthanatized and primary tumors were weighed. Lungs were examined histologically to determine the number of mice with metastasis and tumor emboli. Mean area of the pulmonary micrometastatic foci was determined for mice from each group. RESULTS: Primary tumor size and weight were not significantly different among groups. The number of mice in the mid-dose (200 mg/kg) and high-dose (400 mg/kg) groups with micrometastasis was significantly less than the number of control group mice; however, the number of mice with tumor emboli was not affected by thalidomide treatment. Size of micrometastasis lesions was not affected by thalidomide treatment. CONCLUSIONS AND CLINICAL RELEVANCE: Mean area of micrometastases was not affected by treatment; however, growth of micrometastases had not yet reached an angiogenesis-dependent size. Although thalidomide did not affect growth of primary tumors in mice after xenotransplantation of canine osteosarcoma cells, our findings indicate that thalidomide may interfere with the ability of embolic tumor cells to complete the metastatic process within the lungs.