Laser excitation of hematoporphyrin derivatives (HPD) localizing in tumors of the tracheobronchial tree and bladder is useful in the identification and treatment of those tumors. A comparable utility for HPD in the endoscopic localization of colonic tumors may be possible. In this study the ability of HPD to identify 1,2 dimethylhydrazine (DMH) induced colon cancer in rats is evaluated. A total of 111 rats were studied with HPD. Sixty-nine rats received weekly injections of DMH (20 mg/kg) and 42 received injections of the vehicle alone. Twenty-four hours after the intravenous injection of 5 mg/kg of HPD, 18 DMH-induced tumors were identified by visual fluorescence using excitation by either a blue light (390-436 nm) or an argon laser (488 and 514 nm). This represented 100% of the visually or microscopically detected tumors. Seventy-five fluorescent areas were noted that did not contain evidence of cancer. The majority (63) of false positive areas contained lymphoid follicles. All but 2 false positive areas (73/75, 97%, p less than .001) were seen in DMH-treated animals, suggesting that they were an artifact of DMH treatment. HPD fluorescence did not identify microscopic dysplasia. We conclude that HPD fluorescence is an effective method of identifying early colonic cancer and may have a potential clinical role in patients at high risk for colorectal cancer.
This article summarizes the DeLisa lecture and 3-day course of the same name offered at the 2001 Annual Association of Academic Physiatrists Educational Conference, in Hilton Head, South Carolina. The authors briefly discuss the historical school of medicine management approach and the rationale behind mission-based management. The three components of mission-based management are then reviewed along with issues pertaining to their development, implementation, and utilization. Finally, potential operational and political obstacles related to mission-based management are discussed, and recommendations for avoiding political difficulties are presented.
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