Biomedical subjects
Publications and source records attributed to R C Paniello.
Dimethyl thiourea (DMTU), a known hydroxyl radical scavenger, was tested for its ability to improve survival in acute island skin flaps. Rats receiving 500 mg/kg DMTU 1 hour after flap elevation showed a 23.5% improved survival over saline controls. The role of the hydroxyl radical in ischemia/reperfusion injury, and its proposed mechanism, is discussed.
Vitamins A, C, and E act as antioxidants and as free radical scavengers in biological systems. Glutathione is involved in several reactions in vitamin metabolism and also plays an important role in cell membrane protection against lipid peroxidation by free radicals. We sought to use these natural defense mechanisms against oxygen free radicals formed during reperfusion of ischemic skin flaps. An acute axial random skin flap model was utilized in the rat. Vitamins or glutathione were administered by oral gastric tube or intravenously in the perioperative period, and survival of the flap was measured at 1 week. Glutathione, beta-carotene, ascorbic acid and alpha-D-tocopherol showed mean flap survival of 84% to 89%, each of which was significantly improved over saline controls (67% p less than .0005). The mechanisms and biochemistry of these vitamins, and their interactions with other vitamins and with glutathione, are discussed, along with clinical implications of free radical scavenging and skin flap survival.
This study examines efficacy and optimal treatment variables of photodynamic therapy (PDT) for human head and neck squamous cancer (HNSC) xenografts in athymic mice. Two and four days after injection of hematoporphyrin derivative (HPD), tumors were illuminated with red light from an argon-dye laser. Sixty-three tumors were treated. With HPD dose and light intensity constant at 7.5 mg/kg and 100 mW/cm2, respectively, the extent of tumor necrosis was strongly dependent on duration of light exposure. There was no substantial difference in results for 30- and 60-minute treatment durations between animals injected with HPD 2 and 4 days before treatment. After 30 minutes treatment time, responses were seen in 8 of 10 mice (2 days post-HPD) and 11 of 12 mice (4 days post-HPD). After 60 minutes treatment time, toxicity was high. We conclude that, in this model, PDT is effective in selective killing of HNSC. For future comparison studies in this model, if the indicated HPD dose and light intensity are used we recommend a 2-day delay after HPD injection and a light exposure duration of 30 minutes.
PURPOSE: Strategies for the surveillance of patients with upper aerodigestive tract (UADT) epidermoid cancer after potentially curative treatment are not uniform, and the most suitable regimen remains unknown. We investigated the effect of surgeon age on follow-up strategy. MATERIALS AND METHODS: The 824 members of the Society of Head and Neck Surgeons (SHNS) and the 522 members of the American Society for Head and Neck Surgery (ASHNS) who were not members of the SHNS were surveyed using a custom-designed questionnaire to measure how these surgical experts performed follow-up on patients with UADT cancer. Subjects were asked how often they used 14 specific follow-up modalities for patients with resectable UADT cancer during years 1 to 5 after potentially curative primary treatment. Repeated-measures analysis of variance was used to compare practice patterns by surgeon age, as well as by tumor, node, metastasis (TNM) stage and year postsurgery. RESULTS: Responses from 199 SHNS members (24%) and 221 ASHNS members (42%) were considered assessable. Strategies were highly correlated across TNM stages and years postsurgery for most of the 14 modalities. Mean follow-up intensity differed significantly by surgeon age only for bone scan and liver function tests. Although statistically significant, the differences in surveillance strategies among age groups were clinically small. CONCLUSION: Surveillance practice patterns of surgeons caring for patients after treatment for UADT cancer do not vary substantially with practitioner age. Postgraduate education is a plausible mechanism for this homogenization of practitioner behavior.