ACUTE SKIN RESPONSE IN ALBINO MICE FOLLOWING PORPHYRIN PHOTOSENSITIZATION UNDER OXIC AND ANOXIC CONDITIONS

Abstract Acute normal skin toxicity induced by porphyrin photosensitization has been examined using albino mice. Oxic and anoxic (clamped) skin was exposed to red light (630 nm) 24 h following administration of hematoporphyrin derivative (HpD) or Photofrin II (the active component of HpD). Experiments were also performed to determine the effect of sodium pentobarbital anesthesia on HpD and Photofrin II photosensitization of normal skin. Results from this study demonstrated that comparable levels of acute skin damage were induced by HpD and Photofrin II under oxic conditions but neither porphyrin produced any apparent phototoxicity under anoxic conditions. In addition, the level of skin damage induced by porphyrin photosensitization was not affected by sodium pentobarbital anesthesia.     

SKIN PHOTOSENSITIVITY: DURATION and INTENSITY FOLLOWING INTRAVENOUS HEMATOPORPHYRIN DERIVATES, HpD and DHE

Abstract In this pilot study, the duration and degree of skin photosensitivity after intravenous injection of HpD or DHE was tested sequentially once a week, using a solar simulator delivering 19.5 ± 1.5 J cm⁻² to an area of skin 1.4 cm diameter. The longest duration of skin photosensitivity was 7 weeks amongst the 12 patients studied. In 180 other patients, the incidence of sunburn following PDT was less than 10% over a period of 7 y. Sunburn was always minimal (mild redness and swelling–no blisters), and required no systemic therapy or hospitalization. The reaction subsided within 2-3 days. The low incidence was attributed to good verbal and written instructions in methods of prevention delivered to not only patients, but spouse, family members and friends by the investigator.     

RATIOING FLUOROMETER PROBE FOR LOCALIZING CARCINOMA IN SITU IN BRONCHI OF THE LUNG

Abstract A bronchoscopic ratioing fiuorometer probe, that ratios the red light emitted from bronchial tumor to the green light of autofluorescence upon stimulation by violet light (413 nm) has proven capable of detecting and localizing small bronchial tumors bronchoscopically, 4, 48, and 72 h after intravenous Photofrin II injection. Still to be determined is whether'field averaging'in the case of very small bronchial carcinoma in situ will diminish accuracy. The accuracy, efficiency, and cost of localization by imaging fluorescence bronchoscopy will be compared to that by non-imaging ratioing fiuorometer probe.