Acceleration of ALA-induced PpIX fluorescence development in the oral mucosa.
OBJECTIVE
The development of 5-aminolevulinic acid (ALA)-induced tissue fluorescence is optimal 2-4 hours after ALA application. Goal of this work was to develop a means of accelerating oral topical ALA-induced tissue fluorescence.


METHODS
In 300 hamsters, DMBA (9,10 dimethyl-1,2-benzanthracene) cheek pouch carcinogenesis produced dysplasia in 3-5 weeks. Topical application of 20% ALA in Eucerin was followed by localized ultrasound treatment (1, 3.3 MHz) in 150 animals. In 75 animals, ALA was applied in an Oral Pluronic Lecithin Organogel (OPLO-an absorption enhancer) vehicle. Seventy-five animals received only topical ALA in Eucerin. Hamsters were sacrificed and cryosections underwent fluorescence measurements, histological evaluation, 20-180 minutes after ALA application. One-way ANOVA detected independent effects of pathology on laser-induced fluorescence (LIF). Two-way ANOVA tested for independent effect of pathology and of OPLO, ultrasound, and interaction effects.


RESULTS
Ultrasound significantly (P < 0.05) accelerated tissue fluorescence development.


CONCLUSIONS
Low-frequency ultrasound can accelerate ALA-induced fluorescence development.
Charoenbanpachon
Sirintra
S
Beckman Laser Institute, University of California, Irvine 92612, USA.
Krasieva
Tatiana
T
Ebihara
Arata
A
Osann
Kathryn
K
Wilder-Smith
Petra
P
D000287:Administration, Topical; D000622:Aminolevulinic Acid / Q000494:pharmacology*; D000704:Analysis of Variance; D000818:Animals; D002294:Carcinoma, Squamous Cell / Q000473:pathology; D006224:Cricetinae; D004195:Disease Models, Animal; D009061:Mouth Mucosa / Q000187:drug effects / Q000473:pathology*; D009062:Mouth Neoplasms / Q000469:parasitology; D017319:Photosensitizing Agents / Q000494:pharmacology*; D011336:Probability; D011524:Protoporphyrins / Q000493:pharmacokinetics*; D012680:Sensitivity and Specificity; D013050:Spectrometry, Fluorescence / Q000379:methods*
D017319:Photosensitizing Agents; D011524:Protoporphyrins; D000622:Aminolevulinic Acid; C028025:protoporphyrin IX