Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0849640 (skin damage)
 1,516 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The major side effect of photodynamic therapy (PDT) using Photofrin is enhanced skin sensitivity for sunlight, which persists for 3-8 weeks after injection. Formation of singlet oxygen and radicals is believed to be involved in the basic mechanism of inducing skin damage. Reducing this side effect would make PDT more widely acceptable, particularly for palliative use. Hairless dorsal skin patches of mice, injected with 10 mg kg-1 photofrin intraperitoneally (i.p.) 24 h before illumination, were used to evaluate the effect of increasing light doses. The light was obtained from a halogen lamp and transmitted via a fiber optic to illuminate a field of 2.5 cm2. After establishing a dose-response relationship for single or fractionated light dose illumination of the skin, drugs known to scavenge radicals, quench singlet oxygen or interfere with histamine release were tested for their protective effect. N-acetyl-cysteine (NAC), a radical scavenger, administered i.p. (1000 and 2000 mg kg-1) 1 h before illumination produced a significant decrease in skin damage at light doses > 50 J cm-2 (protection factor of 1.3-1.8). When NAC was administered in a dose of 500 mg kg-1, no protection was observed. Fractionated illumination experiments in combination with multiple injections of NAC (1000 mg kg-1) also failed to show any protection. The addition of Ranitidine, a histamine blocking agent (25-100 mg kg-1), given prior to illumination, resulted in a limited protection at higher light doses. From this study we conclude that NAC could be of value in amelioration of the photosensitivity in patients treated with PDT.
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PMID:Partial protection of photodynamic-induced skin reactions in mice by N-acetylcysteine: a preclinical study. 802 87

One of the limitations of successful use of photodynamic therapy (PDT) employing porphyrins is the acute and long-term cutaneous photosensitivity. This paper describes results of experiments designed to test the effects of two radiation protective agents (WR-2721, 500 mg kg-1 or WR-3689, 700 mg kg-1) on murine skin damage induced by PDT. C3H mice were shaved and depilated three days prior to injection with the photosensitiser, Photofrin (5 or 10 mg kg-1). Twenty-four hours later, the mice were injected intraperitoneally with a protector 30 min prior to Argon dye laser (630 nm) exposure. The skin response was followed for two weeks post irradiation using an arbitrary response scale. A light dose response as well as a drug dose response was obtained. The results indicate that both protectors reduced the skin response to PDT, however WR-2721 was demonstrated to be the most effective. The effect of the protectors on vascular stasis after PDT was determined using a fluorescein dye exclusion assay. In mice treated with Photofrin (5 mg kg-1), and 630 nm light (180 J cm-2) pretreatment with either WR-2721 or WR-3689 resulted in significant protection of the vascular effects of PDT. These studies document the ability of the phosphorothioate class of radiation protective agents to reduce the effects of light on photosensitized skin. They do so in a drug dose-dependent fashion with maximum protection at the highest drug doses.
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PMID:Chemical modification of normal tissue damage induced by photodynamic therapy. 876 55