Share Email Print
cover

Proceedings Paper

Evaluation of ALA-induced PpIX as a photosensitizer for PDT in cats
Author(s): Michael D. Lucroy; Benjamin F. Edwards; George M. Peavy; Tatiana B. Krasieva; Stephen M. Griffey; Bruce R. Madewell
Format Member Price Non-Member Price
PDF $14.40 $18.00
cover GOOD NEWS! Your organization subscribes to the SPIE Digital Library. You may be able to download this paper for free. Check Access

Paper Abstract

Given exogenously, ALA defeats intrinsic regulatory feedback mechanisms allowing intracellular accumulation of protoporphyrin IX (PpIX), a highly efficient photosensitizer. In vivo, PpIX synthesis in neoplastic mammary tissues averages 20-fold higher than in normal mammary tissues. PpIX is retained intracellularly, unlike perivascular localization of other photosensitizers, and it is then cleared quickly from the body. In vitro, ALA induced PpIX production in our laboratory in 6 cell lines tested, including an established feline kidney cell line and dermal fibroblasts from primary skin biopsy explant, resulting in photosensitization. Fluorescent microscopy confirmed PpIX production in skin adnexae following ALA administration in a normal cat. To evaluate toxicity, three cats were treated with a single i.v. dose of ALA (either 100, 200, of 400 mg/kg) and followed for 7 days. Cats receiving 100 or 200 mg/kg ALA i.v. had elevated liver enzymes and bilirubin within 24 hours. Histopathology revealed hydropic changes in the liver and renal fibrosis. The cat receiving 400 mg/kg ALA intravenously had cutaneous flush, bradycardia and apnea associated with ALA administration; within 24 hours the cat was lethargic, anorectic and icteric. ALT, AST and bilirubin concentrations had increased significantly. At necropsy the liver had a prominent lobular pattern; histopathology revealed severe periportal hepatitis and splenic necrosis. Systemically administered ALA induces PpIX production, but toxicity may preclude its clinical application in the cat. PpIX levels seem to be more time dependent than those dependent at these three ALA doses and they are well beyond the saturation point for adequate PpIX conversion. The literature is scant regarding toxicity associated with parenteral administration of ALA.

Paper Details

Date Published: 1 July 1998
PDF: 5 pages
Proc. SPIE 3245, Lasers in Surgery: Advanced Characterization, Therapeutics, and Systems VIII, (1 July 1998); doi: 10.1117/12.312318
Show Author Affiliations
Michael D. Lucroy, Univ. of California/Davis School of Veterinary Medicine (United States)
Benjamin F. Edwards, Univ. of California/Davis School of Veterinary Medicine (United States)
George M. Peavy, Beckman Laser Institute and Medical Clinic (United States)
Tatiana B. Krasieva, Beckman Laser Institute and Medical Clinic (United States)
Stephen M. Griffey, Univ. of California/Davis (United States)
Bruce R. Madewell, Univ. of California/Davis School of Veterinary Medicine (United States)


Published in SPIE Proceedings Vol. 3245:
Lasers in Surgery: Advanced Characterization, Therapeutics, and Systems VIII
Graham M. Watson; Harvey Lui; Lou Reinisch; Penny J. Smalley; Kenneth Eugene Bartels; R. Rox Anderson; Lawrence S. Bass; Kenneth Eugene Bartels; C. Gaelyn Garrett; Lloyd P. Tate; Sharon L. Thomsen; Reza S. Malek; Aaron P. Perlmutter; R. Rox Anderson; Lawrence S. Bass; C. Gaelyn Garrett; Kenton W. Gregory; Harvey Lui; Reza S. Malek; Aaron P. Perlmutter; Lou Reinisch; Penny J. Smalley; Lloyd P. Tate; Sharon L. Thomsen; Graham M. Watson, Editor(s)

© SPIE. Terms of Use
Back to Top