Photodynamic therapy of the normal rat stomach: a comparative study between di-sulphonated aluminium phthalocyanine and 5-aminolaevulinic acid

Loh, C. S.; Bedwell, J.; MacRobert, AJ; Krasner, N; Phillips, David; Bown, SG

doi:10.1038/bjc.1992.295

Cited by 89 publications

(38 citation statements)

References 44 publications

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“…More recently, an exciting avenue of ALA photobiology has opened up with its application to PDT as initiated by Kennedy et al (Pottier et al, 1986;Malik & Lugaci, 1987;Malik et al, 1989;Divaris et al, 1990;Kennedy et al, 1990;Bedwell et al, 1992;Loh et al, 1992;Kennedy & Pottier, 1992;Loh et al, 1993a,b Fluence (J cm-2)…”

Section: Discussionmentioning

confidence: 99%

“…Other approaches for achieving better localisation include local administration of the photosensitiser (Amano et al, 1988;Bachor et al, 1992). Recently, there has been considerable interest in a different approach to PDT in which a precursor, ALA, is administered and synthesis of the photosensitiser, PpIX, accomplished in situ (Pottier et al, 1986;Malik & Lugaci, 1987;Malik et al, 1989;Divaris et al, 1990;Kennedy et al, 1990;Bedwell et al, 1992;Kennedy & Pottier, 1992;Loh et al, 1992Loh et al, , 1993aRebeiz et al, 1992). The synthesis of ALA is the rate-limiting step in non-erythroid cells in the pathway of haem biosynthesis (Martin, 1985) (Rebeiz et al, 1992).…”

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confidence: 99%

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A mechanistic study of cellular photodestruction with 5-aminolaevulinic acid-induced porphyrin

Iinuma

Farshi²,

Ortel³

et al. 1994

Br J Cancer

237

122

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Section: Discussionmentioning

confidence: 99%

mentioning

confidence: 99%

A mechanistic study of cellular photodestruction with 5-aminolaevulinic acid-induced porphyrin

Iinuma

Farshi²,

Ortel³

et al. 1994

Br J Cancer

237

122

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“…In the case of the AlPcS2a light and electron microscopy showed that there was a direct, extensive, photo-damaging action on human tumour cells (LOX xenographs) grown in athymic nude mice whereas treatment of AlPcS4 and light resulted initially in a functional vasogenic response and ultimate damage to the vascular structure of the tumour (Peng et al, 1990). Simple procedures to prepare AlPcS enriched in the active disulphonated derivatives have been reported Ambroz et al, 1991) and their in vivo pattern of photosensitisation have been studied in detail (Nuutinen et al, 1991;Loh et al, 1992). Addition of hydrophobic tertiary butyl (Paquette et al, 1991), phthalimidomethyl (Boyle et al, 1992) or benzene groups (Margaron et al, 1992) on the non-substituted, adjacent benzo rings of disulphonated Pc's further enhances the amphiphilic properties of these drugs resulting in increased potential for direct cell killing during PDT.…”

Section: Discussionmentioning

confidence: 99%

Biological activities of phthalocyanines – XVI. Tetrahydroxy- and tetraalkylhydroxy zinc phthalocyanines. Effect of alkyl chain length on in vitro and in vivo photodynamic activities

Boyle

Leznoff²,

Lier³

1993

Br J Cancer

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Summary Zinc phthalocyanine substituted with four hydroxyl groups attached to the macrocycle, either directly or via spacer chains of three or six carbon atoms, were tested for their photodynamic ability to inactivate Chinese hamster lung fibroblasts (line V-79) in vitro, and to induce regression of EMT-6 tumours grown subcutaneously in Balb/c mice. Their potential to inflict direct cell killing during photodynamic therapy was investigated by examining vascular stasis immediately following photoirradiation using fluorescein as a marker, and also by an in vivo/in vitro EMT-6 cell survival assay. Both of the tetraalkylhydroxy substituted zinc phthalocyanines are effective photodynamic sensitisers in vivo with the tetrapropylhydroxy compound exhibiting about twice the activity of the tetrahexylhydroxy analogue. The differences in activities were accentuated in vitro, the tetrapropylhydroxy compound was two orders of magnitude more potent than the tetrahexylhydroxy analogue in photoinactivating V-79 The photosensitiser currently used, Photofrin II.m (P-II), is a complex mixture of porphyrin dimers and oligomers, the active component of which, as yet, remains unidentified. It is, therefore, of increasing importance that 'second generation' photosensitisers of known composition and increased photodynamic activity are developed to provide an alternative to P-II. Phthalocyanines (Pc's) have been proposed as promising potential PDT agents (for recent reviews see van Rosenthal, 1991) primarily because of the high molar absorptivity of these compounds in the red region of the visible spectrum (et105 M' cm' at 670-680 nm when fully monomerised compared to a103M-'cm'1 at 630nm for P-II) where tissue transmission by visible light is more efficent. Their photodynamic activities in vivo largely depend on pharmacokinetics and intratissular distribution pattern and only limited structure-activity relationships have been put forth (Paquette & van Lier, 1992). Degree of sulfonation of Pc's is the most studied structural variable, however, many alternative substituents are possible and remain unexplored. An approach towards the synthesis of novel Pc's on the basis of known structural data, and good photodynamic properties of related compounds, could be potentially rewarding, and this is the rationale for the current study.Berenbaum et al. (1986) tested the ortho, meta and para isomers of meso-tetra(hydroxyphenyl)porphine (THPP) for their in vivo photodynamic activity and skin photosensitisation. Although the m-and o-THPP have very similar photophysical properties and similar absorbances at the wavelength used for PDT (Bonnett et al., 1988), the m-THPP is twice as effective as o-THPP in sensitising tumours, while o-THPP is four times as potent as m-THPP in sensitising skin. Doses of p-THPP and m-THPP that produce equal tumour necrosis are of the ratio 5:1, while their molar absorbances at the illuminating wavelengths are of the ratio 2:1. These data suggest that m-THPP has considerably greater ability than the para and ortho iso...

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“…Animal experiments have shown that after intravenous (i.v.) ALA administration only certain types of tissues manifest PpIX fluorescence (Bedwell et al, 1992;Loh et al, 1992). This tissue-specific photosensitisation provides a basis for using ALA-induced PpIX for tumour localisation and photodynamic therapy.…”

mentioning

confidence: 99%

In vivo fluorescence kinetics and photodynamic therapy using 5-aminolaevulinic acid-induced porphyrin: increased damage after multiple irradiations

Veen¹,

Leengoed²,

Star³

1994

Br J Cancer

111

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The kinetics of fluorescence in tumour (TT) and subcutaneous tissue (ST) and the vascular effects of photodynamic therapy (PDT) were studied using protoporphyrin IX (PpIX), endogenously generated after i.v. administration of 100 and 200 mg kg-1 5-aminolaevulinic acid (ALA). The experimental model was a rat skinfold observation chamber containing a thin layer of ST in which a small syngeneic mammary tumour grows in a sheet-like fashion. Maximum TT and ST fluorescence following 200 mg kg-1 ALA was twice the value after 100 mg kg-1 ALA, but the initial increase with time was the same for the two doses in both TT and ST. The fluorescence increase in ST was slower and the maximum fluorescence was less and appeared later than in TT. Photodynamic therapy was applied using green argon laser light (514.5 nm, 100 J cm-2). Three groups received a single light treatment at different intervals after administration of 100 or 200 mg kg-1 ALA. In these groups no correlation was found between the fluorescence intensities and the vascular damage following PDT. A fourth group was treated twice and before the second light treatment some fluorescence had reappeared after photobleaching due to the first treatment. Only with the double light treatment was lasting TT necrosis achieved, and for the first time with any photosensitiser in this model this was accomplished without complete ST necrosis. Images Figure 4

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Photodynamic therapy of the normal rat stomach: a comparative study between di-sulphonated aluminium phthalocyanine and 5-aminolaevulinic acid

Cited by 89 publications

References 44 publications

A mechanistic study of cellular photodestruction with 5-aminolaevulinic acid-induced porphyrin

A mechanistic study of cellular photodestruction with 5-aminolaevulinic acid-induced porphyrin

Biological activities of phthalocyanines – XVI. Tetrahydroxy- and tetraalkylhydroxy zinc phthalocyanines. Effect of alkyl chain length on in vitro and in vivo photodynamic activities

In vivo fluorescence kinetics and photodynamic therapy using 5-aminolaevulinic acid-induced porphyrin: increased damage after multiple irradiations

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