Endothelial cell viability in the rat aortic wall.

Aortic allografts may offer advantages over prosthetic materials for aortic valve replacement or reconstruction with a valved aortic conduit. Cellular viability may partly determine long-term allograft performance. To evaluate endothelial cell viability in a rat model, valved aortic conduits were subjected to collagenase digestion. The resulting endothelial cell suspension was labeled with Griffonia simplicifolia agglutinin-fluorescein isothiocyanate (GSA-FITC), a marker specific for vascular endothelial cells of the rat. The cells were then incubated with propidium iodide, which is excluded by viable cells. Flow cytometry evaluated endothelial cell viability by determination of percentage of GSA-FITC-positive cells that were negative for propidium iodide. Aortas were studied immediately after harvest or after storage at 4 degrees C in a nutrient medium for 3 to 21 days. Percentage of viable endothelial cells showed a progressive decline with increasing duration of storage. These results demonstrate flow cytometric measurement of endothelial cell viability, a factor of possible importance in assessing allograft storage methods, and show that endothelial viability declines with prolonged storage at 4 degrees C in a nutrient medium.

The in vivo effect of regional hyperthermia on dunning R3327 prostatic tumor.

This report describes the in vivo effect of regional hyperthermia on male Copenhagen rats implanted with Dunning R3327 prostatic carcinoma. In six rats, a 22-gauge 1.5-cm needle was inserted into the tumor and heated to 46.5 degrees C for 2 hr. Two hyperthermia treatments were administered 48 hr apart. In a separate group of six rats, the needle was inserted into the tumor, but not heated. After treatment, serial measurements of tumor volume and body weight were made twice a week for 4 weeks. From the first day of measurement to day 22, the tumor size in the treated group compared to control was significantly smaller, P = 0.02. In the first 12 days following treatment, the mean value of body weight in the treated and control groups decreased 7% and 3%, respectively. Following this, body weights increased to baseline levels by the end of the study. No other side effects related to hyperthermia were observed and no immediate mortality occurred. In the control group, two rats died from lung metastasis of the prostatic carcinoma after day 22. In the treated group, no lung metastases were found and no rats died before being sacrificed on day 29. Our experiments show that local elevation of the temperature of the Dunning tumor results in the death of tumor cells; at 46.5 degrees C for 2 hr there is marked tumor damage while the rats tolerated the hyperthermia well.

The role of calcium antagonists in the management of renal warm ischemia.

Eighty dogs with solitary kidneys were used to investigate the effects of calcium antagonists on the functional capacity and structural integrity of kidneys subjected to sixty minutes of warm ischemia by transient vascular occlusion under general anesthesia. Treated dogs were compared with control animals who had normal or untreated ischemic kidneys (group 1 and 2) and also with saline-flushed ischemic kidneys without or with heparinization (group 3 and 4). Verapamil and nicardipine were used independently as local (group 5 and 7) or systemic treatment (group 6 and 8). Functional and structural studies revealed that calcium antagonists improved animal survival, renal hemodynamics, renal functional capacity, cellular adenine nucleotides, and reduced the ischemic structural damage. Local treatment of ischemic kidneys with 0.15 mg. nicardipine afforded the best protection against the deleterious effects of renal warm ischemia.