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This study was designed to investigate the effects of PR-350, a newly developed radiosensitizer, on dihydropyrimidine dehydrogenase (DPD) activity and 5-fluorouracil (5-FU) pharmacokinetics in 8-week-old male Sprague-Dawley rats. In an in vitro study with hepatic cytosol, DPD activity was dose-dependently reduced by PR-350 at 0.5, 1.0, and 2.0 mmol/l to 75.5%, 64.9%, and 61.5%, respectively, of the control values. In an ex vivo study, DPD activities in hepatic cytosols obtained from animals which had received PR-350 over 4 days (200 mg/kg per day) were not significantly different from those in animals which had not. In an in vivo study, none of the pharmacokinetic parameters obtained from the plasma concentration-time profile of 5-FU were significantly altered by single i.v. injections of PR-350 (50, 100, or 200 mg/kg). However, (E)-5-(2)-(bromovinyl)uracil (BVU), a DPD inhibitor, significantly increased the half-life and area under the curve of 5-FU to 238.1% and 323.2%, respectively, of the control values. Administration of PR-350 over 4 days (200 mg/kg per day) did not affect either of these parameters. The administration of PR-350 significantly reduced the clearance (73.5% of control) and volume of distribution (71.0% of control) of 5-FU, but the alterations were much less than those caused by BVU. These results suggest that the effect of PR-350 on 5-FU pharmacokinetics is much less than that of BVU and that the enhancement of 5-FU toxicity by PR-350 is less than we initially anticipated. [ABSTRACT FROM AUTHOR]

We recently encountered a patient with a lymphoepithelial cyst of the pancreas with sebaceous differentiation. We sought to compare the characteristics of this patient with those previously reported in order to foster a keener understanding of this rare clinical entity. After reviewing the present patient's case in detail, we conducted a comprehensive review of the English-language literature and analyzed the clinical characteristics of reported cases of lymphoepithelial cysts. Our patient was an asymptomatic 60-year-old man who presented with an incidental finding of a cystic lesion in the tail of the pancreas documented by computed tomography. The cyst was enucleated, and was found to contain keratinized material. It was lined by squamous epithelium with small sebaceous glands, and surrounded by lymphoid tissue with germinal centers. Of 33 reported cases, only 6 (18%) contained sebaceous glands. In all patients who underwent operation, the cysts were easily resected, and the outcome was favorable. Lymphoepithelial cyst of the pancreas is rare, and may be difficult to differentiate from cystic neoplasms preoperatively. Therefore resection is indicated. The diagnosis, however, can be confirmed by careful histologic review, and the prognosis is excellent. [ABSTRACT FROM AUTHOR]