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T. Dougherty, J. Kaufman, A. Goldfarb, K. Weishaupt, D. Boyle, A. Mittleman (1978)
Photoradiation therapy for the treatment of malignant tumors.Cancer research, 38 8
R. Nilsson, P. Merkel, D. Kearns (1972)
KINETIC PROPERTIES OF THE TRIPLET STATES OF METHYLENE BLUE AND OTHER PHOTOSENSITIZING DYESPhotochemistry and Photobiology, 16
E. Rossi, A. Vorst, G. Jori (1981)
COMPETITION BETWEEN THE SINGLET OXYGEN AND ELECTRON TRANSFER MECHANISMS IN THE PORPHYRIN‐SENSITIZED PHOTOOXIDATION OF l‐TRYPTOPHAN AND TRYPTAMINE IN AQUEOUS MICELLAR DISPERSIONSPhotochemistry and Photobiology, 34
Cristina Sconfienza, A. Vorst, G. Jori (1980)
TYPE I AND TYPE II MECHANISMS IN THE PHOTOOXIDATION OF L‐TRYPTOPHAN AND TRYPTAMINE SENSITIZED BY HEMATOPORPHYRIN IN THE PRESENCE AND ABSENCE OF SODIUM DODECYL SULPHATE MICELLESPhotochemistry and Photobiology, 31
K. Suwa, T. Kimura, A. Schaap (1977)
Reactivity of singlet molecular oxygen with cholesterol in a phospholipid membrane matrix. A model for oxidative damage of membranes.Biochemical and biophysical research communications, 75 3
K. Suwa, T. Kimura, A. Schaap (1978)
REACTION OF SINGLET OXYGEN WITH CHOLESTEROL IN LIPOSOMAL MEMBRANES. EFFECT OF MEMBRANE FLUIDITY ON THE PHOTOOXIDATION OF CHOLESTEROLPhotochemistry and Photobiology, 28
S. Anderson, N. Krinsky, M. Stone, D. Clagett (1974)
EFFECT OF SINGLET OXYGEN QUENCHERS ON OXIDATIVE DAMAGE TO LIPOSOMES INITIATED BY PHOTOSENSITIZATION OR BY RADIOFREQUENCY DISCHARGEPhotochemistry and Photobiology, 20
W. Gallagher, W. Elliott (1973)
LIGAND‐BINDING IN PORPHYRIN SYSTEMS *Annals of the New York Academy of Sciences, 206
W. White (1978)
7 – Aggregation of Porphyrins and Metalloporphyrins
G. Cauzzo, Ciorgio Gennari, G. Jori, J. Spikes (1977)
THE EFFECT OF CHEMICAL STRUCTURE ON THE PHOTOSENSITIZING EFFICIENCIES OF PORPHYRINSPhotochemistry and Photobiology, 25
R. Muller-Runkel, J. Blais, L. Grossweiner (1981)
PHOTODYNAMIC DAMAGE TO EGG LECITHIN LIPOSOMES *Photochemistry and Photobiology, 33
(1981)
Photochem. Photobiol
S. Anderson, N. Krinsky (1973)
PROTECTIVE ACTION OF CAROTENOID PIGMENTS AGAINST PHOTODYNAMIC DAMAGE TO LIPOSOMES*Photochemistry and Photobiology, 18
L. Andrews, J. Levy, H. Linschitz (1976)
Kinetic analysis of flash photolysis data for sequential first and second order reactions: The photoreduction of triplet fluorenone by dabcoJournal of Photochemistry, 6
L. Grossweiner, J. Grossweiner (1982)
HYDRODYNAMIC EFFECTS IN THE PHOTOSENSITIZED LYSIS OF LIPOSOMES *Photochemistry and Photobiology, 35
D. Kessel, E. Rossi (1982)
DETERMINANTS OF PORPHYRIN‐SENSITIZED PHOTOOXIDATION CHARACTERIZED BY FLUORESCENCE AND ABSORPTION SPECTRAPhotochemistry and Photobiology, 35
L. Tomio, E. Reddi, G. Jori, P. Zorat, G. Pizzi, F. Calzavara (1980)
Hematoporphyrin as a Sensitizer in Tumor Phototherapy: Effect of Medium Polarity on the Photosensitizing Efficiency and Role of the Administration Pathway on the Distribution in Normal and Tumor-Bearing Rats
Abstract The lysis of phosphatidylcholine (PC) liposomes was sensitized to visible light (>500nm) by hematoporphyrin (HP) incorporated in the liposomes (0.09‐1.5%, wt/wt) or in the external buffer (1‐15 μM). The lytic mechanism changed from the Type II pathway mediated by singlet oxygen (1O2) at low HP concentrations to the anoxic, Type I pathway at high HP concentrations. Spectral measurements of HP in aqueous and organic solvents indicate that the HP was not aggregated (monomers and/or dimers) for Type II sensitization and aggregated for Type I conditions. High concentrations of azide (>0.1 M) or DABCO (>0.5 M) were protective with high HP concentration under oxic and anoxic conditions, which cannot involve the scavenging of 1O2. Feasible protective mechanisms are quenching of the HP triplet state by high azide and repair of the damaged membrane by DABCO via an electron transfer process. There was significant protection against lysis under Type I conditions by low concentrations of ferricyanide (>1 mM), indicative of an electron transfer mechanism. The incorporation of 22 mol % cholesterol in PC liposomes with 1% HP had no effect on the lytic efficiency for oxic and anoxic conditions. Dipalmitoylphosphatidylcholine liposomes incorporating 1% HP showed negligible photosensitized lysis at 50°C compared with PC liposomes with 1% HP at 25°C. The promotion of photosensitized lysis by hydrodynamic agitation observed in prior work with methylene blue (Grossweiner and Grossweiner, 1982) was significant with HP sensitization for both Type I and Type II conditions. Actinometry with PC liposomes incorporating 1% HP indicated that photosensitized lysis was very inefficient, requiring many absorbed quanta per lysed liposome. Preliminary experiments with crude hematoporphyrin derivative (Hpd) showed similar concentration effects on lytic efficiency, where PC liposomes incorporating 0.1% (wt/wt) Hpd were strongly sensitized by oxygen, whereas sensitization by oxygen was insignificant with 3.1% Hpd. The results with HP and crude Hpd indicate that lytic damage in a biomembrane does not necessarily require oxygenation.
Photochemistry & Photobiology – Wiley
Published: Aug 1, 1982
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