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Protoporphyrin IX (protoporphyrin + ix)
Kinds of Protoporphyrin IX Selected AbstractsGrafting of light-activated antimicrobial materials to nylon filmsJOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 1 2003Jennifer Sherrill Abstract Protoporphyrin IX and zinc protoporphyrin IX were grafted to the surface of nylon-6,6 films via an ethylene diamine bridge and a poly(acrylic acid) (PAA) scaffold. X-ray photoelectron spectroscopy showed that approximately 57% of the nylon surface was covered by PAA and approximately 6% of the carboxylic acid groups in PAA were grafted to the ethylene diamine derivative of protoporphyrin IX or its zinc salt. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 41: 41,47, 2003 [source] Clinical Pharmacokinetics of the PDT Photosensitizers Porfimer Sodium (Photofrin), 2-[1-Hexyloxyethyl]-2-Devinyl Pyropheophorbide-a (Photochlor) and 5-ALA-Induced Protoporphyrin IXLASERS IN SURGERY AND MEDICINE, Issue 5 2006David A. Bellnier PhD Abstract Background and Objectives Photodynamic therapy (PDT) uses a photosensitizer activated by light, in an oxygen-rich environment, to destroy malignant tumors. Clinical trials of PDT at Roswell Park Cancer Institute (RPCI) use the photosensitizers Photofrin, Photochlor, and 5-ALA-induced protoporphyrin IX (PpIX). In some studies the concentrations of photosensitizer in blood, and occasionally in tumor tissue, were obtained. Pharmacokinetic (PK) data from these individual studies were pooled and analyzed. This is the first published review to compare head-to-head the PK of Photofrin and Photochlor. Study Design/Materials and Methods Blood and tissue specimens were obtained from patients undergoing PDT at RPCI. Concentrations of Photofrin, Photochlor, and PpIX were measured using fluorescence analysis. A non-linear mixed effects modeling approach was used to analyze the PK data for Photochlor (up to 4 days post-infusion; two-compartment model) and a simpler multipatient-data-pooling approach was used to model PK data for both Photofrin and Photochlor (at least 150 days post-infusion; three-compartment models). Physiological parameters were standardized to correspond to a standard (70 kg; 1.818 m2 surface area) man to facilitate comparisons between Photofrin and Photochlor. Results Serum concentration-time profiles obtained for Photofrin and Photochlor showed long circulating half-lives, where both sensitizers could be found more than 3 months after intravenous infusion; however, estimated plasma clearances (standard man) were markedly smaller for Photofrin (25.8 ml/hour) than for Photochlor (84.2 ml/hour). Volumes of distribution of the central compartment (standard man) for both Photofrin and Photochlor were about the size (3.14 L, 4.29 L, respectively) of plasma volume, implying that both photosensitizers are almost 100% bound to serum components. Circulating levels of PpIX were generally quite low, falling below the level of instrument sensitivity within a few days after topical application of 5-ALA. Conclusion We have modeled the PK of Photochlor and Photofrin. PK parameter estimates may, in part, explain the relatively long skin photosensitivity attributed to Photofrin but not Photochlor. Due to the potential impact and limited experimental PK data in the PDT field further clinical studies of photosensitizer kinetics in tumor and normal tissues are warranted. Lasers Surg. Med. © 2006 Wiley-Liss, Inc. [source] Fluorescence Kinetics of Protoporphyrin-IX Induced from 5-ALA Compounds in Rabbit Postballoon Injury Model for ALA-PhotoangioplastyPHOTOCHEMISTRY & PHOTOBIOLOGY, Issue 5 2008Oh-Choon Kwon Protoporphyrin IX (PpIX) is one of the photodynamically active substances that are endogenously synthesized in the metabolic pathway for heme as a precursor. Aminolevulinic acid-esters are more lipophilic than conventional 5-aminolevulinic acid (ALA) and some of them are currently being approved as new drugs for photodynamic diagnosis (PDD) and photodynamic therapy (PDT). In order to investigate the pharmacokinetics of ALA and ALA-ethyl ester (ALA-ethyl) in the atheromatous plaque and normal aortic wall of rabbit postballoon injured artery, each 60 mg kg,1 of ALA or ALA-ethyl was injected intravenously followed by serial detection of PpIX fluorescence of harvested arteries at 0,48 h post-injection. Maximum PpIX build-up in the atheromatous plaque was seen at 2 h after injecting ALA. In contrast, it occurred at 9 h after injecting ALA-ethyl. In addition, the selective build-up of ALA in the atheromatous plaque compared to normal vessel wall was much higher (10 times) than that of ALA-ethyl. The time of maximum fluorescence intensity of PpIX was employed as drug-light-interval for subsequent PDT treatment of the atheromatous plaque with 50,150 J cm,1 of light dose. Significant reduction in plaque was observed without damage of the medial wall at both groups, but smooth muscle cell (SMC) was still present in the media region below the PDT-treated atheromatous plaque. In conclusion, ALA may be a more effective compound for endovascular PDT treatment of the atheromatous plaque compared with ALA-ethyl based on their pharmacokinetics, but further optimization of PDT methodology remains to remove completely residual SMC in the media for preventing potential restenosis. [source] Study of Protoporphyrin IX (PpIX) Pharmacokinetics After Topical Application of 5-Aminolevulinic Acid in Urethral Condylomata Acuminata,PHOTOCHEMISTRY & PHOTOBIOLOGY, Issue 5 2007Xiu-Li Wang The pharmacokinetics of 5-aminolevulinic acid (ALA)-induced protoporphyrin IX (PpIX) in lesions of urethral condylomata acuminata were investigated. Sixty patients (20 to 60 years old, 48 male and 12 female) were divided randomly into five groups and received topic application of different concentrations of ALA solution (0.5%, 1%, 3%, 5% or 10%). Biopsy was performed between 1 and 7 h and specimens were subjected to histological, PpIX fluorescence and human papillomavirus (HPV) DNA typing analyses. Fluorescence examination confirmed that ALA-induced PpIX fluorescence was dominantly distributed in the HPV-infected epidermis. In contrast, only a minimal amount of PpIX fluorescence was detected in the dermis. The maximal fluorescence intensity was detected at 5 h incubation. Higher ALA concentration (e.g. 5% and 10%) produced a stronger intensity. These results suggest that the topical application of 5,10% ALA solution for 3,5 h is the optimal condition for the photodynamic therapy of urethral condylomata acuminata. The selective damage of the condylomata acuminata lesions in the epidermis without damaging the dermis ensures a better control of recurrence and side effects such as ulceration or scarring. DNA typing showed that all patients were positive for low risk-HPV DNA and among them 18.3% of patients harbored high risk-HPV DNA. [source] Photodynamic Therapy of Cutaneous Lymphoma Using 5-Aminolevulinic Acid Topical ApplicationDERMATOLOGIC SURGERY, Issue 8 2000Arie Orenstein MD Background. Photodynamic therapy (PDT) with topical application of 5-aminolevulinic acid (ALA) is a new and effective modality for treatment of superficial basal and squamous cell carcinomas. Objective. We present the kinetics of ALA-induced protoporphyrin IX (PP) accumulation and the results of ALA PDT treatment on two patients with different stages (stage I and stage III) of mycosis fungoides (MF)-type cutaneous T-cell lymphoma (CTCL). Methods. ALA-Decoderm cream was applied to the lesions for 16 hours. Spectrofluorescence measurements of PP accumulation were carried out before, during, and 1 hour after photoirradiation (580,720 nm) using the VersaLight system. Results. Different patterns of PP fluorescence kinetics were observed in patients with early and advanced stages of the disease. During photoirradiation the intensity of fluorescence decreased depending on the lesion thickness. One hour after the photoirradiation procedure no PP fluorescence was observed in the stage I MF lesion, while in the thick stage III MF lesions, PP fluorescence reappeared; after an additional 10,15 minutes of irradiation PP fluorescence disappeared. Complete response with excellent cosmetic results was observed in the stage I lesion after a single irradiation with a light dose of 170 J/cm2; in five stage III lesions, complete response was achieved after fractionated irradiation with a total light dose of 380 J/cm2 (follow-up at 27 and 24 months, respectively). Conclusion. The results showed a high response of both stage I and stage III MF lesions to ALA PDT. This modality appears to be very effective and can be used successfully for MF treatment. [source] Fluorescence induction of protoporphyrin IX by a new 5-aminolevulinic acid nanoemulsion used for photodynamic therapy in a full-thickness ex vivo skin modelEXPERIMENTAL DERMATOLOGY, Issue 8 2010Tim Maisch Please cite this paper as: Fluorescence induction of protoporphyrin IX by a new 5-aminolevulinic acid nanoemulsion used for photodynamic therapy in a full-thickness ex vivo skin model. Experimental Dermatology 2010; 19: e302,e305. Abstract:, An ex vivo porcine skin model was utilized to analyse the penetration of 5-aminolevulinic acid (5-ALA) contained in a nanoemulsion-based formulation BF-200 ALA (10% 5-ALA-hydrochloride) versus 16% aminolevulinate methyl ester-hydrochloride in a commercially cream (MAL cream) by fluorescence microscopy of their common metabolite protoporphyrin IX (PpIX) after 3, 5, 8 and 12 h. Fluorescence signals of PpIX in pig skin treated with BF-200 ALA were stronger than those for MAL cream. At 8 and 12 h, the PpIX fluorescence signals were 4.8- and 5.0-fold higher than those measured after MAL cream application. Fluorescence signals of PpIX after application of BF-200 ALA were detected in deeper tissue layers of the epidermis than after application of MAL cream (97.2 ± 5.7 ,m for BF-200 ALA vs 42.0 ± 4.2 ,m for MAL cream). These data implicate that BF-200 ALA in photodynamic therapy might lead to a superior therapeutically effect of intraepidermal (in situ) squamous cell carcinomas. [source] A comparison of 5-aminolaevulinic acid- and its heptyl ester: dark cytotoxicity and protoporphyrin IX synthesis in human adenocarcinoma WiDr cells and in athymic nude mice healthy skinEXPERIMENTAL DERMATOLOGY, Issue 11 2009Xiao Pudroma Abstract:, 5-aminolevulinic acid heptyl ester was investigated in human adenocarcinoma WiDr cells and in healthy skin of athymic nude mice in comparison with 5-aminolevulinic acid (ALA). Incubation of WiDr cells with ALA and ALA heptyl ester resulted in production of protoporphyrin IX (PpIX). Concentrations higher than 0.01 mm of ALA heptyl ester and higher than 1 mm of ALA were cytotoxic. The dark cytotoxicity was not related to PpIX. Intracellular localization, photocytoxicity and photobleaching rate of PpIX were the same for both drugs, although a 100 times lower concentration of ALA heptyl ester (0.01 mm) was needed in comparison with ALA (1 mm) to induce the same level of PpIX. ALA heptyl ester, topically (but not systemically) applied, is a promising candidate for fluorescence diagnosis and photodynamic therapy. Special attention must be focused on the concentrations of ALA heptyl ester; as excess may lead to cytotoxicity and inefficient PpIX generation. [source] In vivo production of catalase containing haem analoguesFEBS JOURNAL, Issue 12 2010Myriam Brugna Haem (protohaem IX) analogues are toxic compounds and have been considered for use as antibacterial agents, but the primary mechanism behind their toxicity has not been demonstrated. Using the haem protein catalase in the Gram-positive bacterium Enterococcus faecalis as an experimental system, we show that a variety of haem analogues can be taken up by bacterial cells and incorporated into haem-dependent enzymes. The resulting cofactor-substituted proteins are dysfunctional, generally resulting in arrested cell growth or death. This largely explains the cell toxicity of haem analogues. In contrast to many other organisms, E. faecalis does not depend on haem for growth, and therefore resists the toxicity of many haem analogues. We have exploited this feature to establish a bacterial in vivo system for the production of cofactor-substituted haem protein variants. As a pilot study, we produced, isolated and analysed novel catalase variants in which the iron atom of the haem prosthetic group is replaced by other metals, i.e. cobalt, gallium, tin, and zinc, and also variants containing meso-protoheme IX, ruthenium meso-protoporphyrin IX and (metal-free) protoporphyrin IX. Engineered haem proteins of this type are of potential use within basic research and the biotechnical industry. Structured digital abstract ,,MINT-7722358, MINT-7722368: katA (uniprotkb:Q834P5) and katA (uniprotkb:Q834P5) physically interact (MI:0915) by copurification (MI:0025) [source] Anticancer effect of photodynamic therapy with hexenyl ester of 5-aminolevulinic acid in oral squamous cell carcinomaHEAD & NECK: JOURNAL FOR THE SCIENCES & SPECIALTIES OF THE HEAD AND NECK, Issue 9 2010Yeon-Hee Moon MS Abstract Background. Five-aminolaevulinic acid (ALA) and its derivatives act as precursors of the photosensitizer protoporphyrin IX (PpIX). In this study, the effect of photodynamic therapy (PDT) with hexenyl ester of ALA (ALA-hx) was examined in a human oral squamous cell carcinoma, YD10B cells. Methods. PpIX accumulation and mRNA expression of coproporphyrinogen oxidase (CPO) by ALA and ALA-hx was examined. Cell viability was examined by MTT assay and the molecular mechanism was investigated. Results. The PpIX synthesis and mRNA expression of CPO was much higher in the cells treated with ALA-hx than ALA. At the concentration that PDT with ALA did not affect cell growth, ALA-hx PDT effectively produced reactive oxygen species (ROS) and suppressed cell growth. Growth inhibition by ALA-hx PDT was due to mitochondrial-dependent apoptosis. Conclusion. Our results suggest that ALA-hx PDT effectively induced apoptosis of YD-10B cells and can be considered as a therapeutic alternative for oral cancer. © 2009 Wiley Periodicals, Inc. Head Neck, 2010 [source] In vitro Studies of Functionalized Mesoporous Silica Nanoparticles for Photodynamic TherapyADVANCED MATERIALS, Issue 2 2009Hsiung-Lin Tu A versatile platform for photodynamic therapy (PDT), mesoporous silica nanoparticles functionalized with protoporphyrin IX (PpIX-MSNs), has been developed. In vitro studies on HeLa cells show high uptake efficiency. Phototoxicity results give both irradiation time- and dosage-dependent cell death events. Because of the ease of incorporating other biomedical functional groups, we believe MSNs would be an ideal platform for biomedical applications. [source] Inhibition of heme oxygenase-1 by zinc protoporphyrin IX reduces tumor growth of LL/2 lung cancer in C57BL miceINTERNATIONAL JOURNAL OF CANCER, Issue 3 2007Kaeko Hirai Abstract Heme oxygenase (HO)-1 is a key player reducing cytotoxicity and enhancing protumoral effects of nitric oxide (NO). We examined zinc protoporphyrin (ZnPP) IX, an HO-1 inhibitor, to affect tumor growth of LL/2 mouse lung cancer cells. ZnPPIX reduced HO-1 expression and HO activity in LL/2 cells, whereas cobalt PPIX (CoPPIX), an HO-1 activator, increased both. LL/2 cells treated with sodium nitropurusside, an NO donor, showed growth inhibition dose-dependently, which was enhanced by ZnPPIX cotreatment, but was reduced by CoPPIX. In mice tumors, ZnPPIX decreased HO-1 expression. LL/2-tumors were found in 88% (7/8) vehicle-treated mice, whereas tumors were found in 38% (3/8) and 25% (2/8) mice treated with 5 and 20 ,g/mouse ZnPPIX, respectively (p = 0.0302). Tumor growth was inhibited dose-dependently by ZnPPIX. Vascular endothealial growth factor concentration in tumors was reduced by ZnPPIX (p = 0.0341). Microvessel density (MVD) in ZnPPIX-treated tumors was lower than that in vehicle-treated tumors (p = 0.0362). Apoptotic cell count in ZnPPIX-treated tumors was higher than that in vehicle-treated tumors (p = 0.0003). In contrast, CoPPIX treatment increased HO-1 expression, enhanced tumorigenicity and MVD and reduced apoptosis. From these findings, inhibition of HO-1 by ZnPPIX provides relevant antitumoral effects. © 2006 Wiley-Liss, Inc. [source] Computational study of the solvation of protoporphyrin IX and its Fe2+ complexINTERNATIONAL JOURNAL OF QUANTUM CHEMISTRY, Issue 13 2008Teobaldo Cuya Guizado Abstract Molecular dynamics (MD) simulations of a well known hydrophobic structure, the heme (ferroprotoporphyrin IX) and its precursor in the heme synthesis, protoporphyrin IX (PPIX) are presented. The objective of the present study is to determine the stability of both structures in an aqueous medium, as well as the structure-solvent relation, hydration shells, and discuss their implications for biological processes. The density functional theory (DFT) is used for the electronic and structural characterization of both PPIX and its Fe2+ complex. A classical approach based on the Gromacs package is used for the MD. The radial distribution function g(r) is used to examine the allocation of water molecules around different regions of the porphyrins. The calculations demonstrate the heterogeneous character of the porphyrins with respect to the affinity with water molecules, the general hydrophobic character of the porphyrin ring bonded or not to the ion Fe, the hydrophilic character of the carboxylic oxygen that is unchanged upon iron binding, and the low hydrophilicity of Fe2+ in the heme. © 2008 Wiley Periodicals, Inc. Int J Quantum Chem, 2008 [source] Multiphoton microscopy in life sciencesJOURNAL OF MICROSCOPY, Issue 2 2000K. König Near infrared (NIR) multiphoton microscopy is becoming a novel optical tool of choice for fluorescence imaging with high spatial and temporal resolution, diagnostics, photochemistry and nanoprocessing within living cells and tissues. Three-dimensional fluorescence imaging based on non-resonant two-photon or three-photon fluorophor excitation requires light intensities in the range of MW cm,2 to GW cm,2, which can be derived by diffraction limited focusing of continuous wave and pulsed NIR laser radiation. NIR lasers can be employed as the excitation source for multifluorophor multiphoton excitation and hence multicolour imaging. In combination with fluorescence in situ hybridization (FISH), this novel approach can be used for multi-gene detection (multiphoton multicolour FISH). Owing to the high NIR penetration depth, non-invasive optical biopsies can be obtained from patients and ex vivo tissue by morphological and functional fluorescence imaging of endogenous fluorophores such as NAD(P)H, flavin, lipofuscin, porphyrins, collagen and elastin. Recent botanical applications of multiphoton microscopy include depth-resolved imaging of pigments (chlorophyll) and green fluorescent proteins as well as non-invasive fluorophore loading into single living plant cells. Non-destructive fluorescence imaging with multiphoton microscopes is limited to an optical window. Above certain intensities, multiphoton laser microscopy leads to impaired cellular reproduction, formation of giant cells, oxidative stress and apoptosis-like cell death. Major intracellular targets of photodamage in animal cells are mitochondria as well as the Golgi apparatus. The damage is most likely based on a two-photon excitation process rather than a one-photon or three-photon event. Picosecond and femtosecond laser microscopes therefore provide approximately the same safe relative optical window for two-photon vital cell studies. In labelled cells, additional phototoxic effects may occur via photodynamic action. This has been demonstrated for aminolevulinic acid-induced protoporphyrin IX and other porphyrin sensitizers in cells. When the light intensity in NIR microscopes is increased to TW cm,2 levels, highly localized optical breakdown and plasma formation do occur. These femtosecond NIR laser microscopes can also be used as novel ultraprecise nanosurgical tools with cut sizes between 100 nm and 300 nm. Using the versatile nanoscalpel, intracellular dissection of chromosomes within living cells can be performed without perturbing the outer cell membrane. Moreover, cells remain alive. Non-invasive NIR laser surgery within a living cell or within an organelle is therefore possible. [source] Porphyrin-based, light-activated antimicrobial materialsJOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 15 2003Jadranka Bozja Abstract New light-activated antimicrobial materials with a potentially wide range of possible uses in civilian settings were synthesized by the grafting of protoporphyrin IX and zinc protoporphyrin IX to nylon fibers. These fibers were shown to be active against Staphylococcus aureus at light exposures of 10,000 lux and greater and against Escherichia coli at 60,000 lux. They were ineffective against both strains in the absence of light. At 40,000 lux, these fibers showed increased antimicrobial activity against S. aureus with increasing exposure time. © 2003 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 41: 2297,2303, 2003 [source] Grafting of light-activated antimicrobial materials to nylon filmsJOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 1 2003Jennifer Sherrill Abstract Protoporphyrin IX and zinc protoporphyrin IX were grafted to the surface of nylon-6,6 films via an ethylene diamine bridge and a poly(acrylic acid) (PAA) scaffold. X-ray photoelectron spectroscopy showed that approximately 57% of the nylon surface was covered by PAA and approximately 6% of the carboxylic acid groups in PAA were grafted to the ethylene diamine derivative of protoporphyrin IX or its zinc salt. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 41: 41,47, 2003 [source] Photodynamic therapy with violet light and topical ,-aminolaevulinic acid in the treatment of actinic keratosis, Bowen's disease and basal cell carcinomaJOURNAL OF THE EUROPEAN ACADEMY OF DERMATOLOGY & VENEREOLOGY, Issue 6 2001AT Dijkstra Abstract Background Most clinical studies using photodynamic therapy (PDT) with topical application of ,-aminolaevulinic acid (,-ALA) use red light because it allows greater depth of penetration. However, given the porphyrin-like spectrum of ,-ALA-induced photosensitivity, violet light provides a maximal overlap with the excitation spectrum of protoporphyrin IX, meaning that PDT with violet light uses less light energy to induce the phototoxic reaction. Aim To study the efficacy of violet light in combination with topical ,-ALA PDT in the treatment of premalignant and malignant skin lesions. Methods Eight hours after 20%,-ALA was applied topically, photoirradiation was performed with an incoherent light source (Philips HPM-10, 400 W) emitting predominantly violet light (400,450 nm). Lesions received 10,20 J/cm2 during an exposure time of 30 min. The 38 subjects treated included three with basal cell naevus syndrome with multiple (> 30) superficial and nodular basal cell carcinomas (BCCs), one subject had multiple lesions of Bowen's disease, involving 50% of the scalp, and the remaining 34 subjects presented a total of 35 superficial BCCs, 10 nodular BCCs, four large solar keratoses and five solitary lesions of Bowen's disease. Results Complete remission both clinically and histologically was seen after a single treatment in 82% of the superficial BCCs (100% after a second treatment), 50% of the nodular BCCs, one of the four solar keratosis lesions (partial remission in the other three) and 90,100% of the solitary lesions of Bowen's disease. Conclusions ,-ALA PDT using violet light appears to be a well tolerated and effective alternative treatment for premalignant and malignant skin lesions, especially when there are multiple lesions or large patches comprising a large area of skin. [source] Clinical Pharmacokinetics of the PDT Photosensitizers Porfimer Sodium (Photofrin), 2-[1-Hexyloxyethyl]-2-Devinyl Pyropheophorbide-a (Photochlor) and 5-ALA-Induced Protoporphyrin IXLASERS IN SURGERY AND MEDICINE, Issue 5 2006David A. Bellnier PhD Abstract Background and Objectives Photodynamic therapy (PDT) uses a photosensitizer activated by light, in an oxygen-rich environment, to destroy malignant tumors. Clinical trials of PDT at Roswell Park Cancer Institute (RPCI) use the photosensitizers Photofrin, Photochlor, and 5-ALA-induced protoporphyrin IX (PpIX). In some studies the concentrations of photosensitizer in blood, and occasionally in tumor tissue, were obtained. Pharmacokinetic (PK) data from these individual studies were pooled and analyzed. This is the first published review to compare head-to-head the PK of Photofrin and Photochlor. Study Design/Materials and Methods Blood and tissue specimens were obtained from patients undergoing PDT at RPCI. Concentrations of Photofrin, Photochlor, and PpIX were measured using fluorescence analysis. A non-linear mixed effects modeling approach was used to analyze the PK data for Photochlor (up to 4 days post-infusion; two-compartment model) and a simpler multipatient-data-pooling approach was used to model PK data for both Photofrin and Photochlor (at least 150 days post-infusion; three-compartment models). Physiological parameters were standardized to correspond to a standard (70 kg; 1.818 m2 surface area) man to facilitate comparisons between Photofrin and Photochlor. Results Serum concentration-time profiles obtained for Photofrin and Photochlor showed long circulating half-lives, where both sensitizers could be found more than 3 months after intravenous infusion; however, estimated plasma clearances (standard man) were markedly smaller for Photofrin (25.8 ml/hour) than for Photochlor (84.2 ml/hour). Volumes of distribution of the central compartment (standard man) for both Photofrin and Photochlor were about the size (3.14 L, 4.29 L, respectively) of plasma volume, implying that both photosensitizers are almost 100% bound to serum components. Circulating levels of PpIX were generally quite low, falling below the level of instrument sensitivity within a few days after topical application of 5-ALA. Conclusion We have modeled the PK of Photochlor and Photofrin. PK parameter estimates may, in part, explain the relatively long skin photosensitivity attributed to Photofrin but not Photochlor. Due to the potential impact and limited experimental PK data in the PDT field further clinical studies of photosensitizer kinetics in tumor and normal tissues are warranted. Lasers Surg. Med. © 2006 Wiley-Liss, Inc. [source] Fluorescence staining of human ovarian cancer tissue following application of 5-aminolevulinic acid: Fluorescence microscopy studiesLASERS IN SURGERY AND MEDICINE, Issue 5 2006Martin C. Löning Abstract Background and Objectives Application of 5-aminolevulinic acid (ALA) for fluorescence-guided second-look laparoscopy has been shown to be a promising new procedure in the early diagnosis of ovarian carcinoma metastases. However, for assessing the reliability of this method, information on the microscopic distribution of protoporphyrin IX (PP IX) in the tissue is needed. Additionally, the selectivity of PP IX uptake is essential for a potential photodynamic therapy (PDT) of ovarian cancer metastases. Study Design/Materials and Methods Thirty-six patients with epithelial ovarian cancer and two patients suffering from fallopian tube carcinoma underwent a laparoscopic second-look procedure 5 hours after the application of ALA. In 17 patients 36 fluorescence-guided biopsies were taken from fluorescing and non-fluorescing tissues for further evaluation. Fluorescence microscopy and digital image processing were utilized to determine the presence of PP IX fluorescence. Results A specificity of 88% and a sensitivity of 100% with a negative predictive value of 100% and a positive predictive value of 91% were calculated for PP IX fluorescence on a microscopic level as marker for ovarian cancer metastases. Conclusions On a microscopic scale, ALA-induced PP IX fluorescence is confined to ovarian cancer tumor tissue sparing stromal tissues. Lasers Surg. Med. © 2006 Wiley-Liss, Inc. [source] Increased brain tumor resection using fluorescence image guidance in a preclinical modelLASERS IN SURGERY AND MEDICINE, Issue 3 2004Arjen Bogaards BSc Abstract Background and Objectives Fluorescence image-guided brain tumor resection is thought to assist neurosurgeons by visualizing those tumor margins that merge imperceptibly into normal brain tissue and, hence, are difficult to identify. We compared resection completeness and residual tumor, determined by histopathology, after white light resection (WLR) using an operating microscope versus additional fluorescence guided resection (FGR). Study Design/Materials and Methods We employed an intracranial VX2 tumor in a preclinical rabbit model and a fluorescence imaging/spectroscopy system, exciting and detecting the fluorescence of protoporphyrin IX (PpIX) induced endogenously by administering 5-aminolevulinic acid (ALA) at 4 hours before surgery. Results Using FGR in addition to WLR significantly increased resection completeness by a factor 1.4 from 68±38 to 98±3.5%, and decreased the amount of residual tumor post-resection by a factor 16 from 32±38 to 2.0±3.5% of the initial tumor volume. Conclusions Additional FGR increased completeness of resection and enabled more consistent resections between cases. Lasers Surg. Med. 35:181,190, 2004. © 2004 Wiley-Liss, Inc. [source] Role of Vascular Heme Oxygenase in Reduced Myogenic Reactivity Following Chronic HypoxiaMICROCIRCULATION, Issue 2 2006JAY S. NAIK ABSTRACT Objective: Exposure to chronic hypoxia (CH) results in a persistent endothelium-dependent vascular smooth muscle hyperpolarization that diminishes vasoconstrictor reactivity. Experiments were performed to test the hypothesis that products of both cytochrome P450 epoxygenase (CYP) and heme oxygenase (HO) are required for the persistent diminished myogenic reactivity following CH. Methods: The authors examined myogenic responses of mesenteric arteries isolated from control and CH (48 h; PB = 380 mmHg) rats in the presence of a HO inhibitor (zinc protoporphyrin IX; ZnPPIX) or combined HO and CYP epoxygenase inhibition (sulfaphenazole). Arteries were isolated and cannulated and the vascular smooth muscle was loaded with the Ca2 + indicator Fura-2. Results: Control vessels maintained their internal diameter in response to step increases in intraluminal pressure, whereas arteries from CH animals passively distended. ZnPPIX augmented myogenic reactivity and [Ca2 +] in arteries from CH animals. Combined administration of sulfaphenazole and ZnPPIX did not have an additional effect compared to ZnPPIX alone. Myogenic reactivity in control vessels was not altered by ZnPPIX or ZnPPIX + sulfaphenazole. Conclusions: HO appears to play a role in regulating myogenic reactivity following CH. Furthermore, these data suggest that products of HO and CYP are both required for the observed attenuation in vasoreactivity following CH. [source] Mitigating Photosensitivity of Erythropoietic Protoporphyria Patients by an Agonistic Analog of ,-Melanocyte Stimulating Hormone,PHOTOCHEMISTRY & PHOTOBIOLOGY, Issue 6 2009Juergen H. Harms Erythropoietic protoporphyria (EPP) is a rare hereditary disorder characterized by dermal accumulation of the photosensitizer protoporphyrin IX. Following sunlight exposure, the resulting photosensitivity is manifested first as pain, later as erythema, edema and dermal lesions. Afamelanotide (Nle4 -d-Phe7 -,-MSH), a synthetic analog of ,-melanocyte stimulating hormone and agonist of the melanocortin-1-receptor, promotes melanin synthesis, increasing skin pigmentation. This study examines the efficacy of afamelanotide in preventing symptoms in patients with EPP. A sustained-release subcutaneous implant of 20 mg afamelanotide was administered twice, with a 60-day interval to five EPP patients. Therapeutic efficacy was assessed by a photoprovocation test using standardized white light irradiation, melanin density (MD) determination and daily recording of sunlight exposure and symptoms. From Day 30 to Day 120 tolerance to photoprovocation significantly increased compared with baseline (P = 0.007) and skin MD was significantly higher than that recorded at baseline (P = 0.004). Except for two low-grade pain episodes, patients recorded no phototoxic events past Day 4 of treatment. Tolerance to natural sunlight was up to 24 times longer than prior to therapy. The findings demonstrate beneficial effects of afamelanotide in patients with EPP. Due to the limited number of patients enrolled and the design being an open-label study, confirmation by a large-scale trial is required. [source] siRNA-mediated Knockdown of the Heme Synthesis and Degradation Pathways: Modulation of Treatment Effect of 5-Aminolevulinic Acid-based Photodynamic Therapy in Urothelial Cancer Cell LinesPHOTOCHEMISTRY & PHOTOBIOLOGY, Issue 4 2009Makito Miyake Photodynamic therapy mediated by 5-aminolevulinic acid (ALA-PDT) has been developed as a therapeutic modality for refractory superficial bladder cancers. Here, in experiments using urothelial cancer cell lines, we investigated the effects of siRNA modulating heme-synthetic and degradation pathways for ALA-PDT. Targeted knockdown of ferrochelatase (FECH) suppressed heme synthesis and significantly increased intracellular protoporphyrin IX (PpIX) accumulation, leading to enhanced phototoxicity in four of five cell lines. Heme oxygenase-1 (HO-1) is recognized as important for cytoprotection against oxidative stress such as PDT. Targeted knockdown of HO-1 leads to decreased intracellular PpIX accumulation, resulting in a failure to enhance ALA-PDT effect in four cell lines. Knockdown of HO-1 caused marked growth inhibition in UM-UC-2 overexpressing HO-1, whereas no inhibitory effect was observed in UM-UC-3 lacking HO-1 expression. Moreover, HO-1 protein levels and (GT)n repeat polymorphism of the HO-1 gene promoter region were examined with the implication that the constitutive expressions of HO-1 protein were associated with a shorter (GT)n repeat. Our results suggested that (1) FECH siRNA improved the phototoxicity of ALA-PDT, (2) overexpression of HO-1 was associated with shorter (GT)n repeat of the promoter region, and (3) siRNA-mediated knockdown of HO-1 could suppress the growth of bladder cancer cells overexpressing HO-1. [source] Monitoring ALA-induced PpIX Photodynamic Therapy in the Rat Esophagus Using Fluorescence and Reflectance SpectroscopyPHOTOCHEMISTRY & PHOTOBIOLOGY, Issue 6 2008Bastiaan Kruijt The presence of phased protoporphyrin IX (PpIX) bleach kinetics has been shown to correlate with esophageal response to 5-aminolevulinic acid-based photodynamic therapy (ALA-PDT) in animal models. Here we confirm the existence of phased PpIX photobleaching by increasing the temporal resolution of the fluorescence measurements using the therapeutic illumination and long wavelength fluorescence detection. Furthermore fluorescence differential pathlength spectroscopy (FDPS) was incorporated to provide information on the effects of PpIX and tissue oxygenation distribution on the PpIX bleach kinetics during illumination. ALA at a dose of 200 mg kg,1 was orally administered to 15 rats, five rats served as control animals. PDT was performed at an in situ measured fluence rate of 75 mW cm,2 using a total fluence of 54 J cm,2. Forty-eight hours after PDT the esophagus was excised and histologically examined for PDT-induced damage. Fluence rate and PpIX photobleaching at 705 nm were monitored during therapeutic illumination with the same isotropic probe. A new method, FDPS, was used for superficial measurement on saturation, blood volume, scattering characteristics and PpIX fluorescence. Results showed two-phased PpIX photobleaching that was not related to a (systematic) change in esophageal oxygenation but was associated with an increase in average blood volume. PpIX fluorescence photobleaching measured using FDPS, in which fluorescence signals are only acquired from the superficial layers of the esophagus, showed lower rates of photobleaching and no distinct phases. No clear correlation between two-phased photobleaching and histologic tissue response was found. This study demonstrates the feasibility of measuring fluence rate, PpIX fluorescence and FDPS during PDT in the esophagus. We conclude that the spatial distribution of PpIX significantly influences the kinetics of photobleaching and that there is a complex interrelationship between the distribution of PpIX and the supply of oxygen to the illuminated tissue volume. [source] Study of Protoporphyrin IX (PpIX) Pharmacokinetics After Topical Application of 5-Aminolevulinic Acid in Urethral Condylomata Acuminata,PHOTOCHEMISTRY & PHOTOBIOLOGY, Issue 5 2007Xiu-Li Wang The pharmacokinetics of 5-aminolevulinic acid (ALA)-induced protoporphyrin IX (PpIX) in lesions of urethral condylomata acuminata were investigated. Sixty patients (20 to 60 years old, 48 male and 12 female) were divided randomly into five groups and received topic application of different concentrations of ALA solution (0.5%, 1%, 3%, 5% or 10%). Biopsy was performed between 1 and 7 h and specimens were subjected to histological, PpIX fluorescence and human papillomavirus (HPV) DNA typing analyses. Fluorescence examination confirmed that ALA-induced PpIX fluorescence was dominantly distributed in the HPV-infected epidermis. In contrast, only a minimal amount of PpIX fluorescence was detected in the dermis. The maximal fluorescence intensity was detected at 5 h incubation. Higher ALA concentration (e.g. 5% and 10%) produced a stronger intensity. These results suggest that the topical application of 5,10% ALA solution for 3,5 h is the optimal condition for the photodynamic therapy of urethral condylomata acuminata. The selective damage of the condylomata acuminata lesions in the epidermis without damaging the dermis ensures a better control of recurrence and side effects such as ulceration or scarring. DNA typing showed that all patients were positive for low risk-HPV DNA and among them 18.3% of patients harbored high risk-HPV DNA. [source] On the Role of Iron and one of its Chelating Agents in the Production of Protoporphyrin IX Generated by 5-Aminolevulinic Acid and its Hexyl Ester Derivative Tested on an Epidermal Equivalent of Human SkinPHOTOCHEMISTRY & PHOTOBIOLOGY, Issue 4 2006Pascal Uehlinger ABSTRACT Photodynamic therapy (PDT) with 5-aminolevulinic acid (ALA) or its derivatives as precursors of protoporphyrin IX (PPIX) is routinely used in dermatology for the treatment of various pathologies. However, this methodology suffers to some extent from a limited efficacy. Therefore, the main goal of this study was to investigate the modulation and pharma-cokinetics of PPIX buildup after a 5 h incubation with ALA (1.5 mM) and one of its derivatives, the hexyl ester of ALA (h-ALA) (1.5 mM), on the human epidermal equivalent EpidexÔ. PPIX production was modulated with (L+) ascorbic acid iron (II) salt (LAI) or the iron (II)-specific chelating agent deferoxamine (DFO). PPIX fluorescence from the EpidexÔ layers was measured up to 150 h after the precursor administration using a microspectrofluorometer (,ex: 400 ± 20 nm; ,det: 635 nm). The maximum PPIX fluorescence intensity induced by h-ALA was about 1.7x larger than that induced by ALA. The addition of DFO resulted in a more than 50% increase in PPIX fluorescence for both precursors. The decay half life measured for PPIX fluorescence is 30 and 42.5 h, respectively, for ALA and h-ALA. These half lives are doubled when the samples contain DFO. In the samples with the highest fluorescence intensity, a modified fluorescence spectrum was observed after 10 h, with the emergence of a peak at 590 nm, which is attributed to zinc protoporphyrin IX (Zn PPIX). [source] Self-sensitized Photodegradation of Membrane-bound Protoporphyrin Mediated by Chain Lipid Peroxidation: Inhibition by Nitric Oxide with Sustained Singlet Oxygen DamagePHOTOCHEMISTRY & PHOTOBIOLOGY, Issue 2 2005Magdalena Niziolek ABSTRACT In the presence of exciting light, iron and reductants, the singlet oxygen (1O2)-generating sensitizer protoporphyrin IX (PpIX) induces free radical lipid peroxidation in membranes, but gradually degrades in the process. We postulated that NO, acting as a chain-breaking antioxidant, would protect PpIX against degradation and consequently prolong its ability to produce 1O2. This idea was tested by irradiating PpIX-containing liposomes (LUVs) in the presence of iron and ascorbate, and monitoring the cholesterol hydroperoxides 5,-OOH and 7,/,-OOH as respective 1O2 and free radical reporters. 5,-OOH accumulation, initially linear with light fluence, slowed progressively after prolonged irradiation, whereas 7,/,-OOH accumulation only accelerated after an initial lag. The active, but not spent, NO donor spermine NONOate (0.4 mM) virtually abolished 7,/,-OOH buildup as well as 5,-OOH slowdown. Increasing membrane phospholipid unsaturation hastened the onset of rapid chain peroxidation and 5,-OOH slowdown. Accompanying the 5,-OOH effect was a steady decrease in 1O2 quantum yield and PpIX fluorescence at 632 nm, both of which were inhibited by NO. An NO-inhibitable decay of PpIX fluorescence was also observed during dark incubation of 5,-OOH-bearing LUVs with iron and ascorbate, confirming a link between chain peroxidation and PpIX loss. By protecting PpIX in irradiated membranes, NO might select for and prolong purely 1O2 -mediated damage. Supporting this was our observation that 1O2 -mediated photoinactivation of a nonmembrane target, lactate dehydrogenase, slowed concurrently with 5,-OOH accumulation and that spermine NONOate prevented this. Thus, NO not only protected membrane lipids against PpIX-sensitized free radical damage, but PpIX itself, thereby extending its 1O2 -generating lifetime. Consistent findings were obtained using porphyrin-sensitized COH-BR1 cells. These previously unrecognized effects of NO could have important bearing on 5-aminolevulinate-based photodynamic therapy in which PpIX is metabolically deposited in tumor cells. [source] Kinetics of Protoporphyrin IX Formation in Rat Oral Mucosa and Skin After Application of 5-Aminolevulinic Acid and its Methylester,PHOTOCHEMISTRY & PHOTOBIOLOGY, Issue 2 2005Stefan Kristiansson ABSTRACT The kinetics of accumulation of protoporphyrin IX (PpIX) after topical application of 5-aminolevulinic acid (ALA) and its methylester (5-aminolevulinic acid methylester [ALA-Me]) was studied on rat oral mucosa. The accumulation of PpIX in mucosa and skin after intravenous injection of ALA and ALA-Me was also studied. The elimination rate of PpIX was dependent on drug and dose as well as on administration route. Application of ALA on rat oral mucosa and skin caused a systemic effect with PpIX building up in remote skin sites not exposed to the drugs. No such systemic effect was seen after application of ALA-Me either in mucosa or on skin. Intravenous injection of the drugs (0.2 g/kg) leads to more fluorescence in the skin than topical application of the drug (20%). For mucosa, the opposite is true. Maximal PpIX fluorescence appeared later after application of high concentrations of the drugs (around 8 h for 5% and 20% wt/wt) than after application of low concentrations (around 3,5 h for 1% and 2% wt/wt). [source] Phototoxicity of Protoporphhyrin IX, Diarginine Diprotoporphyrinate and N,N-Deiphenylalanyl Protoporphyrin Toward Human Fibroblasts and ketratinocytes In vitro: Effect of 5-Methoxypsoralen,PHOTOCHEMISTRY & PHOTOBIOLOGY, Issue 3 2004Andrzej Bugaj The phototoxicity of two new porphyrin photosensitizers, diarginine diprotoporphyrinate (PP(Arg)2) and N,N -diphenylalanyl protoporphyrin (PP(Phe)2), and the synergistic effect of 5-methaoxyposralen (5-MOP) have been studied in comparison with that of protoporphyrin IX (PPIX). Under ultraviolet A (UV-A) irradiation (,= 365 nm), the phototoxicity of the porphyrins toward cultured human fibroblasts and keratino-cytes decerases in the order: PPIX > PP(Arg)2 > PP(Phe)2. A synergistic efect of 5-MOP on the phototoxicity of PPIX, PP(Arg)2 and PP(Phe)2 has been observed. The combination of PPIX, PP(Arg)2 and PP(Phe)2 with 0.1,0.5 ,M 5-MOP significantly potentiates the phototoxicity of the three porphyrins. The most effective potentiation was observed with the water-soluble PP(Arg)2 and 5-MOP concentrations lowere than 0.75 ,M. Above this 5-MOP concnetration this potentiation is abolished. The intracellular concentration of PPIX and PP(Phe)2 is independent of the presence of 5-MOP. On the other hand, the intracellular contnet of PP(Arg)2 is decerased in concentration-dependent manner by the psoralen. Illumination with red light, not absorbed by 5-MOP, leads to a weak potentiation of the PP(Arg)2 phototoxic effect in the presence of 5-MOP, suggesting that dark interaction of 5-MOP with cell membranes aggravated by porphyrin photosensitization is involved in the observed phenomena. The results are tentatively explained by differences in hydrophobicity and molecular structure of the examined photosensitizers. PPIX, which is barely soluble in water, has a significantly higher affinity for cell membranes and simultaneously exerts a stronger phototoxic effect than PP(Arg)2 whose solubility in water is high. On the other hand, the weak phototoxicity of PP(Phe)2 could be explained by the steric hindrance brought by the phenylalanyl substituents on the pyrrole ring. The loss in the PP(Arg)2 cell content probably explains the inhibition of the synergistic effect of 5-MOP on the PP(Arg)2 phototoxicity at high 5-MOP concentration. This study suggests that PP(Arg)2 in combinatin with 5-MOP might reveal a strong phototoxic effect when applied to skin cancer treatment. [source] 5-Aminolevulinic Acid-Based Photodynamic Therapy in Leukemia Cell HL60,PHOTOCHEMISTRY & PHOTOBIOLOGY, Issue 6 2004Su-Juan Zhang ABSTRACT A study to explore the optimal experimental parameters and the photosensitization of 5-aminolevulinic acid (ALA)-based photodynamic therapy (PDT) in promyelocytic leukemia cell HL60 has been conducted, in which HL60 cells and their control groups, peripheral blood mononuclear cell (PBMC), first are incubated with different concentrations of ALA in dark for different periods of time and then followed by irradiating with different wavebands for different fluences. Fluorescence microscope and spectrofluorometer have been used to detect the fluorescence of protoporphyrin IX (PpIX) endogenously produced by ALA. The response of the cells to ALA-PDT was evaluated by the 3-(4,5-dimethyl-2-thiazolyl)-2-5-diphenyl-2H-tetrazolium bromide (MTT) assay (interval between irradiation and the MTT assay is 24 h) and by flow cytometry (the length of time between irradiation and the flow assay is 30 min). MTT results will reflect the relative number of metabolically active mitochondria in the population. Propidium iodide uptake in flow cytometry will test for membrane damage. The results of parameter experiments were obtained: 1 × 105/mL HL60 cell was first incubated with 1 mmol/L ALA in dark for 4 h and the maximum fluorescence of PpIX level appeared; then irradiated with 410 nm (4 mW/cm2) for 14.4 J/cm2 and maximum photodamage to membrane and mitochondrial function of HL60 cell resulted. With the normal granulocytes, such response was not detected. Therefore a hypothetical idea can be brought forward that ALA-based PDT can be used for inactivation of leukemia cell HL60 and these optimal parameters may be useful for clinical application. [source] New 5-Aminolevulinic Acid Esters,Efficient Protoporphyrin Precursors for Photodetection and Photodynamic Therapy,PHOTOCHEMISTRY & PHOTOBIOLOGY, Issue 5 2003H. Brunner ABSTRACT Photodetection (PD) and photodynamic therapy (PDT) with 5-aminolevulinic acid (ALA),induced protoporphyrin IX (PPIX) accumulation are approaches to detect and treat dysplasia and early cancer in the gastrointestinal tract and in the urinary bladder. Because ALA-induced PPIX production is limited, we synthesized ALA ester hydrochlorides 3,22 and tested them in two different in vitro models (gastrointestinal tract: HT29,CCD18; urinary bladder: J82,UROTSA). PPIX accumulation after incubation with 0.12 mmol/L for 3 h and PPIX accumulation as a function of different incubation times were measured using flow cytometry. 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assays were performed to check cellular dark toxicity. Phototoxicity after irradiation was tested. ALA nonafluorohexylester hydrochloride 11, ALA thiohexylester hydrochloride 13 and ALA dibenzyldiester dihydrochloride 19 induced appreciably increased PPIX levels and showed improved phototoxicity compared with the references ALA hydrochloride 1, ALA hexylester hydrochloride 3 and ALA benzylester hydrochloride 4. Thus, the new compounds 11, 13 and 19 are promising compounds for PD and PDT. [source] | |||||||||||||||||||