The effect of the quality of dietary protein on the post-initiation development of aflatoxin B1-initiated putatively preneoplastic foci in Fischer 344 rat liver was compared with the effect of the quantity of dietary protein. Feeding wheat gluten, a low-quality protein, during the postinitiation period (between the end of aflatoxin B1 dosing and the death of the rats) inhibited the development of gamma-glutamyltransferase-positive foci when compared with that in animals fed high-quality protein (casein) diets during the same period. Lysine supplementation of wheat gluten during the postinitiation period enhanced the gamma-glutamyltransferase-positive response to a level comparable with that of the high-quality protein. These results suggest that one can inhibit the development of foci either by decreasing the quantity of protein intake and holding the quality of the protein constant or by decreasing the quality and holding the quantity constant.

Cryoablation of the adrenal gland can be obtained in an effective, controllable, and reproducible manner. This controllable energy form may provide new modality for tissue destruction where adrenal gland preservation is necessary and can be delivered by the laparoscopic approach. Understanding the effect of adrenal cryoablation may allow us to treat selected patients with small tumors in whom organ preservation is necessary.

Adrenalectomy is indicated for patients with large adrenal lesions or functional tumors. Cryoablation is currently used as a surgical alternative for the treatment of prostate, lung, brain, pharynx, and liver tumors. The purpose of this study was to determine if cryosurgery could be delivered to small areas in the adrenal gland in a controllable and reproducible manner such that tissue could heal in a nonpathologic way. A total of 14 female mongrel dogs underwent acute (n = 8) or chronic (4 weeks, n = 6) cryoablation using the Cryounit. In the acute study using an open transabdominal approach a 2-mm cryoprobe was placed interstitially into the adrenal tissue, whereas 0.032-inch thermocouples were cannulated into the ipsilateral adrenal artery and vein. Adrenal parenchymal temperature changes were measured using 0.032-inch thermocouples placed at 0.4- and 0.8-cm intervals from the cryoprobe. In the chronic study, cryoablation was achieved by transperitoneal laparoscopic access using a standard laparoscopic technique. Interstitial cryoprobe temperatures decreased from 33.1 +/- 1.9 degrees C to -148 +/- 1.2 degrees C following 15 min of freezing in the acute study. Cryoablation of adrenal tissue achieved temperatures of -41.8 +/- 5.7 degrees C and -21.8 +/- 1 degrees C at distances of 0.4 and 0.8 cm from the cryoprobe, respectively. There was no significant change in adrenazl artery or vein temperatures during cryoablation. Histologically there is a clear demarcation between viable and nonviable tissue characterized by areas of multifocal hemorrhage and pyknosis. After 4 weeks of healing a well-defined line of necrotic and viable tissue is visible. Cryoablation of the adrenal can be delivered in an effective, controllable, and reproducible manner. This controllable energy form may provide a new treatment modality for tissue destruction where adrenal gland preservation is necessary and can be performed by the laparoscopic approach. Understanding the effect of adrenal cryoablation may allow us to treat selected patients with small tumors where organ preservation is necessary.