Phototransformations of 5-Aminolevulinic Acid-induced Protoporphyrin IX in vitro: A Spectroscopic Study¶

Bagdonas, Saulius; Ma, Liang; Iani, Vladimir; Rotomskis, Ričardas; Juzenas, Petras; Moan, Johan Emelian

doi:10.1562/0031-8655(2000)0720186poaaip2.0.co2

Cited by 23 publications

(40 citation statements)

References 49 publications

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“…Similar considerations apply to the photodegradation mechanism of mTHPC and other sensitizers such as protoporphyrin IX (PPIX). In fact, a Type‐II–mediated mechanism need not necessarily involve direct reaction with the singlet oxygen, and bleaching may result from oxidation by reactive oxidizing intermediates such as peroxy radicals formed by reaction of singlet oxygen with biological substrates, as proposed for PPIX (51). Such reactive oxygen intermediates would presumably survive longer within cells than singlet oxygen itself; therefore, this indirect singlet oxygen–mediated mechanism could be feasible and make a major contribution to mTHPC bleaching.…”

Section: Discussionmentioning

confidence: 99%

Intracellular Photobleaching of 5,10,15,20-Tetrakis(m-hydroxyphenyl) chlorin (Foscan®) Exhibits a Complex Dependence on Oxygen Level and Fluence Rate¶

Kunz¹,

MacRobert²

2007

Photochemistry and Photobiology

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The understanding of photosensitizer photobleaching is important not only for mechanistic studies, but also for the development of monitoring techniques for clinical dosimetry in photodynamic therapy. In this study, we investigated the intracellular photobleaching of 5,10,15,20‐tetrakis(m‐hydroxyphenyl)chlorin (mTHPC, Foscan®) in the murine macrophage cell line J774A.1, using quantitative fluorescence imaging microscopy, microspectrofluorometry and microspectrophotometry. Using 652 nm laser irradiation, it was found that mTHPC exhibits oxygen‐ and fluence rate–dependent intracellular photobleaching. The kinetics showed an inverse dose–rate behavior, i.e. a reduction of fluence rate resulted in more photobleaching at comparable fluences. The effect of deoxygenation was found to be more complex, with decreased bleaching at low fluence rates and increased bleaching at higher fluence rates. The intracellular formation of reactive oxygen species was measured using 2′,7′‐dichlorodihydrofluorescein diacetate. The results are analyzed in terms of competitive Type‐I and Type‐II mechanisms.

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Section: Discussionmentioning

confidence: 99%

Intracellular Photobleaching of 5,10,15,20-Tetrakis(m-hydroxyphenyl) chlorin (Foscan®) Exhibits a Complex Dependence on Oxygen Level and Fluence Rate¶

Kunz¹,

MacRobert²

2007

Photochemistry and Photobiology

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“…[166][167][168][169][170][171] The main photoproducts of porphyrin photodegradation are probably non-fluorescent. It was proposed that one pathway of photodegradation of porphyrins, such as of Hp, HpD, PpIX and mesoporphyrin, might be that the porphyrin is epoxidised at the double-bond between the ring and the methine bridge.…”

Section: Photodegradation Of Photosensitizersmentioning

confidence: 99%

Milestones in the development of photodynamic therapy and fluorescence diagnosis

Juzeniene

Peng

Moan

2007

Photochem Photobiol Sci

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251

196

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Many reviews on PDT have been published. This field is now so large, and embraces so many sub-specialties, from laser technology and optical penetration through diffusing media to a number of medical fields including dermatology, gastroenterology, ophthalmology, blood sterilization and treatment of microbial-viral diseases, that it is impossible to cover all aspects in a single review. Here, we will concentrate on a few basic aspects, all important for the route of development leading PDT to its present state: early work on hematoporphyrin and hematoporphyrin derivative, second and third generation photosensitizers, 5-aminolevulinic acid and its derivatives, oxygen and singlet oxygen, PDT effects on cell organelles, mutagenic potential, the basis for tumour selectivity, cell cooperativity, photochemical internalization, light penetration into tissue and the significance of oxygen depletion, photobleaching of photosensitizers, optimal light sources, effects on the immune system, and, finally, future trends.

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“…The obtained spectrum of the photoproducts corresponds well to the spectrum of Photoprotoporphyrin, a product of reaction of 1 O 2 with PpIX. 9,44 Besides these two principal°uorophores, another emitting species was observed in several spots in lesion of one of the MAL-treated animals (see Fig. 5 48 The subtraction of the two principal components obtained from SVD reveals another emission band of this species at 689 nm (see inset in Fig.…”

Section: Resultsmentioning

confidence: 95%

Parallel fluorescence and phosphorescence monitoring of singlet oxygen photosensitization in rats

Dědic

Stíbal

Vyklický

et al. 2015

J. Innov. Opt. Health Sci.

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The time-and spectral-resolved set-up for measurements of weak infrared luminescence of photosensitizers (PSs) and singlet oxygen using optical lightguides was used on skin of laboratory animals in vivo. Wistar rats with abdominal incisions treated by methylis aminolevulinitis (MAL) were used as a model. A control group of animals with abdominal incisions was also tested. Spectrally resolved°uorescence of the PS was acquired during the treatment from the same spot. The intensity and spectral pro¯le of the°uorescence signal from the skin can be used to guide the detection setup to the investigated spots in the lesion. The rate of bleaching of Protoporphyrin IX band and appearance of a band of its photoproducts during the treatment can be characterized by the exposition E D , under which the latter becomes dominant feature in°uorescence spectrum. E D value di®ers statistically signi¯cantly between the normal skin and the lesion treated by MAL. No direct proportionality was found between the°uorescence signal and singlet oxygen production. Nevertheless, the strong°uorescence signal is necessary but not a su±cient condition for higher singlet oxygen production in vivo. E D value correlates rather well with production of * Corresponding author. This is an Open Access article published by World Scienti¯c Publishing Company. It is distributed under the terms of the Creative Commons Attribution 3.0 (CC-BY) License. Further distribution of this work is permitted, provided the original work is properly cited. Vol. 8, No. 6 (2015) 1550037 (14 pages singlet oxygen, but di®erently in lesion and normal skin. Lifetimes of singlet oxygen di®er between spots outside and in the lesion. PS triplet state lifetimes exhibit weak di®erence between spots treated and untreated by MAL. Journal of Innovative Optical Health Sciences

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Phototransformations of 5-Aminolevulinic Acid-induced Protoporphyrin IX in vitro: A Spectroscopic Study¶

Cited by 23 publications

References 49 publications

Intracellular Photobleaching of 5,10,15,20-Tetrakis(m-hydroxyphenyl) chlorin (Foscan®) Exhibits a Complex Dependence on Oxygen Level and Fluence Rate¶

Intracellular Photobleaching of 5,10,15,20-Tetrakis(m-hydroxyphenyl) chlorin (Foscan®) Exhibits a Complex Dependence on Oxygen Level and Fluence Rate¶

Milestones in the development of photodynamic therapy and fluorescence diagnosis

Parallel fluorescence and phosphorescence monitoring of singlet oxygen photosensitization in rats

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