Photosensitizer localization

Topical Temporary change in pigmentation, photosensitivity, Local inflammatory reactions (peeling, dry skin, stinging, erythema, pruritus) are to be expected and are reversible with discontinuation of tretinoin... 

Peng, Q. et al. (1996) Correlation of subcellular and intratumoral photosensitizer localization with ultrastructural features after photodynamic therapy, Ultrastruct. Path. 20, 109-129. 

One potential approach extends the idea of chemical amplification introduced in our preceding description of dry-film resists. In 1982, Ito and co-workers (37,38) recognized that if a photosensitizer producing an acidic product is photolyzed in a polymer matrix containing acid-labile groups, the acid will serve as a spatially localized catalyst for the formation or cleavage of chemical bonds. 

Materials. For holographic information storage, materials are required which alter their index of refraction locally by spotwise illumination with light. Suitable are photorefractive inorganic crystals, eg, LiNbO, BaTiO, LiTaO, and Bq2 i02Q. Also suitable are photorefractive ferroelectric polymers like poly(vinyhdene fluoride-i o-trifluorethylene) (PVDF/TFE). Preferably transparent polymers are used which contain approximately 10% of monomeric material (so-called photopolymers, photothermoplasts). These polymers additionally contain different initiators, photoinitiators, and photosensitizers. 

GL 25] ]R 8] [P 27] After irradiation for only 5 s, high conversions (> < obtained [21]. This is explained as being due to both the high absorption coefficient of the photosensitizer Bengal Rose and the high local number density of photons within the micro channel as a result of the large specific surface area. 

Photodynamic therapy uses non-thermal red light to activate verteporfin, which produces reactive oxygen species that locally damage the neovascular endothelium.24 Verteporfin treatment reduces the risk of loss of visual acuity and legal blindness over 1 to 2 years. Long-term results are not yet available. Severe photosensitivity for 3 to 5 days after the procedure is common and some patients experience a severe loss of vision. Eventually, most patients have some visual recovery. This procedure requires multiple treatments over time.22... 

In spite of the heavy atom, compound (32) is sufficiently fluorescent for this to be used as an analytical tool to examine localization and pharmacokinetics. In EMT-6 murine tumors, (32) localizes initially on lysosomes, with selectivity for tumor over surrounding normal tissue, and with evidence for apoptotic cell kill.137 Fluorescence studies using a hamster cheek pouch model show a maximum emission in 2-3 h, with selectivity for the tumor (x 1.5 over normal tissue) after 24 h the photosensitizer is no longer detectable.138 Lutetium texaphyrin (32) has been compared... 

Octaalkylphthalocyanines with the alkyl groups at the 1,4,8,11,15,18,22,25- positions have been synthesized as their zinc(II) complexes for PDT studies.238 Tumor localizing and tumor photosensitizing properties have been presented for the octapentyl239 and octadecyl240 compounds. Zinc(II) tetrakis(w-hydroxyalkyl)phthalocyanines have been prepared and tested in vivo, the tetrakis(3-hydroxypropyl) compound being the most active.241... 

The most photosensitive part of the coleoptile with respect to phototropism is the apical 50 qm-zone. The first millimeter of the tip is 160 times more sensitive than the second, and the second millimeter 1,800 times more sensitive than the third 108h In 1937, Bunning29 showed by microchemical method that there is a high concentration of carotenoid (lutein) below the tip of the avena coleoptile, from 250 jum to 2 mm below this point and just in the extreme tip no carotenoid is found. This calls in question whether the enormous local differences in sensitivity can solely be caused by corresponding different absorption gradients. This doubt is further substantiated by the fact, that carotenoid deficient mutants (containing 5 to 10% of the normal siblings) show normal phototropic sensitivity. 

Peng Q, Moan J, Nesland JM, Rimington C (1990) Aluminum phthalocyanines with asymmetrical lower sulfonation and with symmetrical higher sulfonation a comparison of localizing and photosensitizing mechanism in human tumor LOX xenografts. Int J Cancer 46 719-26. 

Szeimies RM, Karrer S, Abels C, Steinbach P, Fickweiler S, Messmann H, Baumler W, Landthaler M (1996) 9-Acetoxy-2,7,12,17-tetrakis-(beta-methoxyethyl)-porphycene (ATMPn), a novel photosensitizer for photodynamic therapy uptake kinetics and intracellular localization. J Photochem Photobiol B 34 67-72. 

Presently photodynamic therapy (PDT) is considered as a perspective way for therapy of different diseases, including cancer. PDT is a method based on the local light-induced activation of photosensitizers able to accumulate selectively in energy-deficient cells (malignant or dysplastic ones) not influencing the remaining normal cells of the body (Pass, 1993). Upon the action of irradiation of certain wavelength characteristic for individual photosensitizer, photochemical reaction occurs... 

Castano AP, Demidova TN, Hamblin MR (2005) Mechanisms in photodynamic therapy Part three - Photosensitizer pharmacokinetics, biodistribution, tumor localization and modes of tumor destruction. Photodiagnosis and Photodynamic Therapy 2 91-106. 

Chemistry and Structure of the Principal Tumor-Localizing Porphyrin Photosensitizer in Hematoporphyrin Derivative... 

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