Fluorescence detection of a new photosensitizer, PAD-S31, in tumour tissues and its use as a photodynamic treatment for skin tumours in dogs and a cat: a preliminary report.
We describe here the detection by fluorescence of a new photosensitizer, PAD-S31, in tumours in dogs and cats and the effect of photodynamic therapy (PDT) by using PAD-S31 for skin tumours in two dogs and one cat. PAD-S31 is a hydrophilic photosensitizer that has two peaks at absorption wavelengths 406 and 665 nm in distilled water. In a preliminary experiment in mice transplanted with SCCVII and colon 26, PAD-S31 was retained in tumour tissues rather than in other organs. The tumours resected from dogs and cats after intravenous administration of PAD-S31 at a dose of 15 mg/kg emitted strong red fluorescence under light illumination of 402 nm wavelength. Animals given PAD-S31 showed no cutaneous photosensitivity under room light illumination. Irradiation at laser light 670 nm wavelength (fluence rate 150 mW/cm2 and total light dosage 150 J/cm2) on cutaneous mast cell tumours in dogs ( n=2 ) and a cutaneous basal cell tumour in a cat induced complete remission. These results suggest PAD-S31 could be a promising photosensitizer for use in a small animal veterinary practice.
Tanabe
S
S
Laboratory of Veterinary Internal Medicine, Department of Veterinary Clinical Science, Obihiro University of Agriculture and Veterinary Medicine, 2-11 Inada, Obihiro, Hokkaido 080-8555, Japan. tanabe@obihiro.ac.jp
Yamaguchi
M
M
Iijima
M
M
Nakajima
S
S
Sakata
I
I
Miyaki
S
S
Takemura
T
T
Furuoka
H
H
Kobayashi
Y
Y
Matsui
T
T
Uzuka
Y
Y
Sarashina
T
T
D000818:Animals; D002371:Cat Diseases / Q000188:drug therapy*; D002415:Cats; D045744:Cell Line, Tumor; D004283:Dog Diseases / Q000188:drug therapy*; D004285:Dogs; D005260:Female; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D008809:Mice, Inbred C3H; D010778:Photochemotherapy / Q000379:methods / Q000662:veterinary*; D017319:Photosensitizing Agents / Q000627:therapeutic use*; D011166:Porphyrins / Q000627:therapeutic use*; D012878:Skin Neoplasms / Q000188:drug therapy / Q000662:veterinary*; D013050:Spectrometry, Fluorescence
C446480:13,17-bis(1-carboxypropionyl)carbamoylethyl-3-ethenyl-8-ethoxyiminoethylidene-7-hydroxy-2,7,12,18-tetramethyl porphyrin; D017319:Photosensitizing Agents; D011166:Porphyrins