Topic
Protoporphyrin IX
About: Protoporphyrin IX is a research topic. Over the lifetime, 2250 publications have been published within this topic receiving 65544 citations. The topic is also known as: PpIX.
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TL;DR: Magnesium-protoporphyrin IX (or its monomethyl ester) is the first committed intermediate in the biosynthesis of chlorophyll in green plants.
21 citations
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TL;DR: It is suggested that low concentrations of haem-related molecules with porphyrin rings in the presence of other stimulating agent are important for ROS production and possibly the onset of TRALI.
Abstract: Background Transfusion-related acute lung injury (TRALI) is associated with vascular endothelial cell injury following neutrophil activation. Recently, it has been suggested that haem-related molecules induce activation of neutrophils and that erythrocyte-derived substances contained in blood preparations are involved in TRALI. We observed the morphological effects and reactive oxygen species (ROS) production of haem-related molecules and investigated the effects of signal transduction inhibitors on haem-induced neutrophil activation. Materials and methods The polymorphonuclear cell fraction was isolated and stimulated using a control stimulant, PMA or fMLP, or by haem-related molecules, haemin, ferric citrate, or protoporphyrin IX. After stimulation, neutrophil was analysed using electron microscopy, a flowcytometer (FCM) and confocal laser scanning microscope to determine the fluorescent intensity of aminophenyl fluorescein (to detect ROS). Results In FCM analysis, haemin and protoporphyrin IX, both of which have a porphyrin ring, induced ROS production in neutrophils. Ferric citrate, which has no porphyrin ring, did not induce neutrophil activation. Haemin alone induced ROS production at relatively high concentrations, whereas low-level fMLP acted as an agonist in the presence of low concentrations of haemin. Haem-related molecules induced ROS production in neutrophil granules through signal transduction in a way similar to PMA. However, in electron microscopy studies, haemin stimulated neutrophils showed minute process at their surface and did not show the vacuolation observable following stimulation with PMA or fMLP. Discussion We suggest that low concentrations of haem-related molecules with porphyrin rings in the presence of other stimulating agent are important for ROS production and possibly the onset of TRALI. The ROS production induced by these molecules is dependent on a signal transduction pathway in a way similar to PMA.
21 citations
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TL;DR: Results indicate that DFO enhances the photodynamic sensitivity of 5-ALA in non-responsive carcinoma cells as a result of increased cellular accumulation by inhibiting haeme biosynthesis.
21 citations
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TL;DR: The influence of two different comonomers incorporated separately at 1 %w/w into a poly(N-isopropylacrylamide) microgel is investigated by photon correlation spectroscopy, transmission electron microscopy and high sensitivity differential scanning calorimetry.
Abstract: The influence of two different comonomers incorporated separately at 1 %w/w into a poly(N-isopropylacrylamide) microgel is investigated by photon correlation spectroscopy, transmission electron microscopy and high sensitivity differential scanning calorimetry The synthesis, characterisation and subsequent binding affinity of iron protoporphyrin IX to the microgels was also investigated Mossbauer and electronic absorbance spectroscopies were used to characterise the resulting protoporphyrin IX iron(III) polymer complexes Co-polymer microgels containing either sulfide or imidazole residues acted as a matrix for the binding of haems to form soluble molecular structures containing multiple iron centres
21 citations
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TL;DR: Photodynamic therapy using 5‐aminolevulinic acid‐induced protoporphyrin IX (PpIX) for sensitization is a promising treatment for carcinoma in situ and diffuse premalignant changes of the bladder.
Abstract: Background and Objective
Photodynamic therapy (PDT) using 5-aminolevulinic acid (ALA)-induced protoporphyrin IX (PpIX) for sensitization is a promising treatment for carcinoma in situ and diffuse premalignant changes of the bladder. We studied the biodistribution of PpIX in a range of tissues with oral and intravesical routes of administration of ALA and compared the photodynamic effects on bladder and skin.
Study Design/Materials and Methods: Normal Wistar rats were given oral or intravesical ALA and PpIX levels in the liver, kidney, skin, and bladder measured by fluorescence microscopy on tissue sections. At the time of maximum PpIX levels, the bladder and skin on the back were illuminated with light at 630 nm and the PDT effects compared.
Results
PpIX fluorescence in the urothelium after 200 mg/kg given intravesically was comparable to that found after 100 mg/kg orally. The ratio of PpIX levels between the urothelium and the underlying muscle was the same for both routes of administration, although there appeared to be more selectivity of urothelial PDT necrosis after intravesical administration. Skin photosensitization was greater after oral ALA, the epidermal PpIX level being three times higher than after intravesical administration for comparable urothelial levels and the PDT effect being more marked.
Conclusions
Intravesical instillation is preferable to oral administration of ALA for PDT ablation of the urothelium of the rat bladder without damage to the underlying tissue layers and for minimizing skin photosensitivity. The technique is now ready for clinical trials. Lasers Surg. Medicine 20:254–264, 1997. © 1997 Wiley-Liss, Inc.
21 citations