Presence Of Hematoporphyrin Research Articles

X-irradiation of Human Cells in Culture in the Presence of Haematoporphyrin

X-irradiation of Human Cells in Culture in the Presence of Haematoporphyrin

Photodynamic effects on human cells exposed to light in the presence of hematoporphyrin. pH effects

Human cells derived from a carcinoma in situ (NHIK 3025) were exposed in vitro to visible light and hematoporphyrin at different pH levels. The cells were inactivated more efficiently at pH 6.7 and 7.2 than at pH 7.8. The treatment with light and hematoporphyrin also induced DNA damage more efficiently at the former pH values than at the latter one. The variation in the efficiency of the photodynamic effect with the pH is mainly due to the fact that the cellular uptake of hematoporphyrin increases with decreasing pH.

Lysosome destruction and lipoperoxide formation due to active oxygen generated from haematoporphyrin and UV irradiation.

The lysosomal enzymes, acid-phosphatase and beta-glucuronidase, were released from rat liver lysosome when exposed to 400 nm irradiation in the presence of haematoporphyrin, and the release was prevented by adding vitamin E, diazabicyclo-octane, bovine serum albumin, superoxide dismutase or D-mannitol to the reaction mixture. Monochromatic irradiation with wavelengths from 380 to 410 nm caused no significant differences in the release of lysosomal enzymes, but 420 nm irradiation caused three-fifths of that of 400 nm irradiation. The malondialdehyde level in rat liver homogenate increased after 400 nm irradiation in the presence of haematoporphyrin. Reduction of nitroblue-tetrazolium was not observed when haematoporphyrin was excited by 400 nm; it was considered that superoxide anion radical (O2--) was not primarily generated. The following mechanism was assumed: that porphyrin which had been excited by 400 nm, converted ground-state molecular oxygen (3O2) to excited singlet oxygen (1O2), which formed lipid peroxides in lysosomal membrane resulting in destruction of the membrane; skin changes would occur from these released lysosomal enzymes.

Lipoperoxide formation of lysosome due to hematoporphyrin and ultraviolet light irradiation.

The malondialdehyde (MDA) contents in rat liver lysosomes increased in vitro by 400 nm ultraviolet light irradiation in the presence of hematoporphyrin (HP), but no changes were observed without HP. The MDA formation under the presence of HP was prevented by addition of vitamin E as antioxidant.

Photodynamic inactivation of cancer cells in vitro. Effect of irradiation temperature and dose fractionation

Human cancer cells in vitro (NHIK 3025), derived from a carcinoma in situ are inactivated when exposed to visible light in the presence of hematoporphyrin. Irradiation at 4 degrees C results in much more efficient inactivation than irradiation at 37 degrees C. Furthermore, a given total light dose is more efficient when it is fractionated than when it is given in a single exposire. These findings may be taken advantage of in future photochemotherapy of cancer.

The mechanism of photodynamic inactivation of human cells in vitro in the presence of haematoporphyrin

The photosensitizing effect of haematoporphyrin (HP) on human cells of the established line NHIK 3025 has been studied. Fluorescence measurements show that HP is bound to these cells. Serum proteins also bind HP, and the presence of 10% human serum during incubation with HP (3 X 10(-4)M) reduces the cellular uptake of HP by 75% or more. The photosensitized inactivation is enhanced when the cells are suspended in D2O-buffer during irradiation. This indicates that singlet oxygen is involved in the inactivation. Two findings indicate that the photoinduced damage is repairable: firstly, the fraction of cells surviving a given light dose decreases with decreasing irradiation temperature, and secondly, the survival curves have a shoulder at low exposures of light.

The Effect of Haematoporphyrin Derivative on the Uptake of 67Ga, 59Fe and 65Zn in Tumours

The effect of prior administration of haematoporphyrin derivative on the uptake in tumours of 67Ga, 59Fe and 65Zn has been studied in tumour-bearing rats and mice. An approximately two-fold increase in the uptake of 67Ga was observed in the August 15 rat tumour when the nuclide was administered 17 to 24 hr after haematoporphyrin. No increase in the uptake of 67Ga occurred in three mouse tumours. Haematoporphyrin administration did not affect the uptake of 65Zn and 59Fe in any of the tumour systems. It is concluded that the presence of haematoporphyrin does not markedly increase the ability of tumours to accummulate metallic radionuclides.

Singlet oxygen as a mediator in the hematoporphyrin-catalyzed photooxidation of NADPH to NADP+ in deuterium oxide

The oxygen-dependent photooxidation of NADPH in the presence of hematoporphyrin in D2O results in the production of enzymatically active NADP+. The reaction is not inhibited by benzoate, mannitol, superoxide dismutase, or catalase. Moreover, addition of either potassium superoxide or H2O2 does not potentiate the reaction. This suggests OH-, H2O2, and O-2 are not likely to be the reactive oxygen species in this system. The oxidation is inhibited by various singlet oxygen quenchers and inhibitors such as 1,4-diazabicyclo[2.2.2]octane, 2,5-dimethylfuran plus methanol, histidine, and methionine. In addition, the rate of oxidation in H2O is less than one-fifth of that in D2O. The results suggest a singlet oxygen-mediated process. During the oxidation, no superoxide radical production could be detected with either ferricytochrome c or nitroblue tetrazolium. However, H2O2 has been found as one of the products. These observations are consistent with an oxidation-reduction reaction between singlet oxygen and NADPH to form H2O2 and NADP+, catalyzed by the light-activated photosensitizer hematoporphyrin.

The photodynamic modification of DNA by hematoporphyrin

Illumination (white light: 300–750 nm) of DNA in the presence of hematoporphyrin ( ⩾ 5 · 10 −4 M ) results in selective degradation of the guanine moiety. DNA so illuminated exhibits physical chemical properties (lowered sedimentation coefficients, lower temperatures of helix-coil transitions, increased buoyant density values) consistent with single-chain scissions (and the generation of single-stranded regions) which presumably are secondary to the photodegradation of the guanine residue. Illumination of DNA in the presence of low levels of hematoporphyrin ( ⩽2.5 · 10 −4 M ) results in a biopolymer exhibiting all of the physical properties described above with the exception of a lowered sedimentation coefficient; on the contrary such DNA is aggregated. Of the four usual deoxynucleosides irradiated in the presence of hematoporphyrin, only deoxyguanosine is destroyed.

Selective photosensitized oxidation of the methionyl residues in elastase.

In recent years, significant advances have clarified the mechanism of photosensitized oxidations (see, for example, Foote, 1968), especially as regards the nature of the reactive oxidizing agents. This fact stimulated the development of reaction systems which allow selective photooxidation of specific components of biological macromolecules (Spikes and Livingston, 1969; Spikes and MacKnight, 1970). In the field of proteins, the selective conversion of the methionyl residues to the sulfoxide can be achieved by irradiation with visible light in the presence of hematoporphyrin at neutral or acid pH (Jori et al., 1969).

Conversion of Light to Chemical Free Energy: I. Porphyrin-sensitized photoreduction of ferredoxin by glutathione

Abstract Iron analysis and titration data show that each mole of ferredoxin from Clostridium pasteurianum reduces 2 moles of ferricyanide. The midpoint reduction potentials of the first and second reducing equivalents of this bacterial ferredoxin are found to be -0.367 and -0.398 volt, respectively. In aqueous solutions at pH 7.4 under helium, the oxidized ferredoxin is photoreduced by glutathione in the presence of hematoporphyrin. After the illumination, the reaction system slowly returns in the dark to its original condition in the absence of oxygen. Calculations based on the present data and the literature value of the midpoint potential of glutathione show that 3.2 kcal of light energy are stored per mole of electrons transferred from glutathione to ferredoxin in the final reaction mixture. The spectrometric and electron spin resonance data show that in this reaction the excited hematoporphyrin first captures an electron from glutathione to form a porphyrin radical, which then transfers its extra electron to ferredoxin.

On the Presence of Haematoporphyrin in the Integument of certain Invertebrates

The Journal of PhysiologyVolume 7, Issue 3 p. 240-252 ArticleFree Access On the Presence of Haematoporphyrin in the Integument of certain Invertebrates C. A. Mac Munn, C. A. Mac MunnSearch for more papers by this author C. A. Mac Munn, C. A. Mac MunnSearch for more papers by this author First published: 01 June 1886 https://doi.org/10.1113/jphysiol.1886.sp000219Citations: 21AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat Citing Literature Volume7, Issue3June 1, 1886Pages 240-252 RelatedInformation