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PubMed1999

Optimum porphyrin accumulation in epithelial skin tumours and psoriatic lesions after topical application of delta-aminolaevulinic acid.

Photodynamic therapy with topically applied delta-aminolaevulinic acid is used to treat skin tumours by employing endogenously formed porphyrins as photosensitizers. This study examines the time course of porphyrin metabolite formation after topical application of delta-aminolaevulinic acid. Porphyrin biosynthesis in human skin tumours (basal cell carcinoma, squamous cell carcinoma), in psoriatic lesions, and in normal skin was investigated. Skin areas were treated with delta-aminolaevulinic acid, and levels of total porphyrins, porphyrin metabolites and proteins were measured in samples excised after 1, 2, 4, 6, 9, 12 and 24 h. There was an increase in porphyrin biosynthesis in all tissues with maximum porphyrin levels in tumours between 2 and 6 h and in psoriatic lesions 6 h after treatment. The pattern of porphyrins showed no significant difference between normal and neoplastic skin, protoporphyrin being the predominant metabolite. The results suggest that optimum irradiation time for superficial epithelial skin tumours may be as soon as 2 h after application of delta-aminolaevulinic acid, whereas for treatment of psoriatic lesions an application time of 6 h is more suitable.

Administration, Topical↗
PubMed2003

Synthesis of meso-substituted porphyrins carrying carboranes and oligo(ethylene glycol) units for potential applications in boron neutron capture therapy.

Selective delivery of 10B to tumours is one of the major remaining problems in boron neutron capture therapy (BNCT) of cancer. Porphyrins are selectively accumulated in tumours. Thus two series of carborane-carrying porphyrins were constructed, with additional functionality for attachment of uncharged potentially water-solubilising polyethers. 3-(1,2-Dicarbaclosododecaboran(12)-1-ylmethoxy)benzaldehyde was prepared by protection of the aldehyde of 3-(prop-2-ynyloxy)benzaldehyde as a dithioacetal, treatment with decaborane(14) and deprotection. Condensation with a 3-nitrophenyldipyrromethane gave a separable mixture of meso-(3-nitrophenyl)-meso-(3-carboranylmethoxyphenyl)porphyrins, resulting from extensive scrambling at the porphyrinogen stage. Similarly, condensation of 3-(1,2-dicarbaclosododecaboran(12)-1-yl)benzaldehyde with this dipyrromethane gave an analogous mixture of meso-(3-nitrophenyl)-meso-(3-carboranylphenyl)porphyrins. In this second series, the two regioisomeric bis(nitrophenyl)bis(carboranylphenyl)porphyrins could only be distinguished by X-ray crystallography, their NMR spectra being identical. The nitro groups of the mono(nitrophenyl)porphyrins and the bis(nitrophenyl)-porphyrins were reduced to the corresponding amines with tin(II) chloride and the monoamines were coupled with a omega-methoxy poly(ethylene glycol) chloroformate of mean MW 600 to give the MeOPEGylated tricarboranyl porphyrins.

Boranes↗
PubMed2005

Spectroscopic study of ALA-induced endogenous porphyrins in arthritic knee tissues: targeting rheumatoid arthritis PDT.

The inflamed synovium of rheumatoid arthritis exhibits many features typical for neoplastic tissue implying that the photodynamic therapy might be an efficient modality for chronic poliarthritis. The accumulation of endogenously produced porphyrins after administration of exogenous 5-aminolevulinic acid (ALA) in a rabbit model of rheumatoid arthritis was evaluated by fluorescence spectroscopy. Independent of the way, intravenously or intra-articularly, in which ALA was administered to the experimental animals, the highest fluorescence intensity of endogenously produced porphyrins was detected in the tissues of the inflamed joints. Besides, the application of ALA had a systemic sensitising effect on the whole organism of rabbits. The highest amount of endogenously produced porphyrins in the inflamed joints measured from the surface of the skin above the synovium tissues was detected 1-3 h after the administration of ALA. Fluorescence measurements performed on the tissue specimens ex vivo showed the predominant accumulation of porphyrins in the synovium of the inflamed joints. The fluorescence of porphyrins was also observed in the cartilage tissues taken from knee joints. However, the fluorescence spectra features indicated that the composition of porphyrins detected in the cartilage tissues was different than that in the synovial tissues. The selective accumulation of porphyrins in the inflamed synovial tissues stands up for the application of photodynamic therapy in the treatment of rheumatoid arthritis and implies the possibility to use optical non-invasive methods based on fluorescence detection of endogenously produced porphyrins for diagnostics of inflamed tissues.

Aminolevulinic Acid↗
PubMed2005

New PEG-ylated Mn(III) porphyrins approaching catalytic activity of SOD enzyme.

Two new tri(ethyleneglycol)-derivatized Mn(III) porphyrins were synthesized with the aim of increasing their bioavailability, and blood-circulating half-life. These are Mn(III) tetrakis(N-(1-(2-(2-(2-methoxyethoxy)ethoxy)ethyl)pyridinium-2-yl)porphyrin, MnTTEG-2-PyP5+ and Mn(III) tetrakis(N,N'-di(1-(2-(2-(2-methoxyethoxy)ethoxy)ethyl)imidazolium-2-yl)porphyrin, MnTDTEG-2-ImP5+. Both porphyrins have ortho pyridyl or di-ortho imidazolyl electron-withdrawing substituents at meso positions of the porphyrin ring that assure highly positive metal centered redox potentials, E1/2 = +250 mV vs. NHE for MnTTEG-2-PyP5+ and E1/2 = + 412 mV vs. NHE for MnTDTEG-2-ImP5+. As expected, from established E1/2 vs. log kcat(O2 *-) structure-activity relationships for metalloporphyrins (Batinic-Haberle et al., Inorg. Chem., 1999, 38, 4011), both compounds exhibit higher SOD-like activity than any meso-substituted Mn(III) porphyrins-based SOD mimic thus far, log kcat = 8.11 (MnTTEG-2-PyP5+) and log kcat = 8.55 (MnTDTEG-2-ImP5+), the former being only a few-fold less potent in disproportionating O2*- than the SOD enzyme itself. The new porphyrins are stable to both acid and EDTA, and non toxic to E. coli. Despite elongated substituents, which could potentially lower their ability to cross the cell wall, MnTTEG-2-PyP5+ and MnTDTEG-2-ImP5+ exhibit similar protection of SOD-deficient E. coli as their much smaller ethyl analogues MnTE-2-PyP5+ and MnTDE-2-ImP5+, respectively. Consequently, with anticipated increased blood-circulating half-life, these new Mn(III) porphyrins may be more effective in ameliorating oxidative stress injuries than ethyl analogues that have been already successfully explored in vivo.

Escherichia coli↗
PubMed1990

Binding of porphyrin to human serum albumin. Structure-activity relationships.

The equilibrium binding of hydroxyethyl vinyl deuteroporphyrin (HVD) and of irreversible porphyrin aggregates to human serum albumin was studied at the molecular level. This protein may function as an endogenous drug carrier for porphyrins in photodynamic therapy of tumours. HVD-protein binding studies revealed two types of binding sites, which are attributed to the two HVD isomers. The binding constant for the high-affinity isomer, 2.1 (+/- 0.3) x 10(8) M-1, is similar to that previously determined for protoporphyrin. At the same time the binding constant for the lower-affinity HVD isomer, 1.8(+/- 0.3) x 10(6) M-1, is similar to that previously determined for haematoporphyrin. Irreversible porphyrin aggregates were purified from the haematoporphyrin derivative and from Photofrin and are defined by spectral and chromatographic data. Gel-exclusion studies indicate that the dominant size of these aggregates is ten porphyrin monomeric units. The protein-binding constant of these aggregates is 1.7(+/- 0.2) x 10(5) M-1, with four binding sites per protein molecule. The distinction between the HVD isomers along the porphyrin-protein affinity sequence gives insight into the relationship of porphyrin structure to porphyrin-albumin binding. On the basis of this study an evaluation of human serum albumin as an endogenous carrier for porphyrins (at various aggregation states) in photodynamic therapy of tumours is presented.

Binding Sites↗
PubMed1993

Porphyrin profiles in the nestling European starling (Sturnus vulgaris): a potential biomarker of field contaminant exposure.

Porphyrin patterns in avian and mammalian tissues and/or excreta have been proposed as qualitative and quantitative biomarkers of exposure to polyhalogenated hydrocarbons, heavy metals, and other environmental contaminants. However, no widely distributed terrestrial species has been characterized as a suitable model in which to assess porphyrin profiles in the evaluation of environmental contaminant exposure. The European starling, whose nests can be readily established and manipulated on contaminated sites, has many qualities that accommodate controlled field research and that suggest its suitability for such assessments. In the present studies, we measured the total and individual porphyrin concentrations in liver, kidney, and fecal-urate excreta of nestling starlings from a noncontaminated field site from day of hatch through d 17 of the nestling period. Total as well as individual 8-, 7-, 6-, 5-, 4-, and 2-carboxyl porphyrin concentrations in liver, kidney, and fecal-urate excreta were readily detectable by high-performance liquid chromatography (HPLC) spectrofluorometric techniques and displayed tissue-specific patterns throughout the developmental period. Liver and fecal-urate porphyrin patterns were established by d 4 subsequent to hatch and remained constant through d 17 of development, whereas renal porphyrin profiles were constant throughout the entire developmental period. In controlled field studies, nestling starlings were treated with either HgCl2 or hexachlorobenzene (HCB), and tissue and excreta porphyrins were extracted and evaluated. The findings suggest that the nestling starling may serve as a suitable model species in which to monitor the effects of field contaminant exposure to wildlife based on chemical-induced changes in tissue or excreta porphyrin levels.

Animals↗
PubMed1998

Intraoperative detection of malignant gliomas by 5-aminolevulinic acid-induced porphyrin fluorescence.

OBJECTIVE: Survival after surgery and radiotherapy for the treatment of malignant gliomas is linked to the completeness of tumor removal. Therefore, methods that permit intraoperative identification of residual tumor tissue may be of benefit. In a preliminary investigation, we have studied the value of fluorescent porphyrins that accumulate in malignant tissue after administration of a precursor (5-aminolevulinic acid) for labeling of malignant gliomas in nine patients. METHODS: Three hours before the induction of anesthesia, 10 mg 5-aminolevulinic acid/kg body weight was administered orally. Intraoperatively, red porphyrin fluorescence was observed with a 455-nm long-pass filter after excitation with violet-blue (375-440 nm) xenon light and was verified by analysis of fluorescence spectra. Fluorescing and nonfluorescing samples taken from the tumor perimeters were examined histologically or used to study the photobleaching of porphyrins by excitation light and white light from the operating microscope. Plasma and erythrocyte porphyrin levels were determined by fluorescence photometry. RESULTS: Normal brain tissue revealed no porphyrin fluorescence, whereas tumor tissue was distinguished by bright red fluorescence. For a total of 89 tissue biopsies, sensitivity was 85% and specificity was 100% for the detection of malignant tissue. For seven of nine patients, visible porphyrin fluorescence led to further resection of the tumor. Under operating light conditions, fluorescence decayed to 36% in 25 minutes for violet-blue light and in 87 minutes for white light. Plasma and erythrocyte porphyrin contents increased slightly, without exceeding normal levels. CONCLUSION: Our observations suggest that 5-aminolevulinic acid-induced porphyrin fluorescence may label malignant gliomas safely and accurately enough to enhance the completeness of tumor removal.

Aged↗
PubMed1986

The interactions of cytochrome c and porphyrin cytochrome c with cytochrome c oxidase. The resting, reduced and pulsed enzymes.

Cytochrome c oxidase forms tight binding complexes with the cytochrome c analog, porphyrin cytochrome c. The behaviour of the reduced and pulsed forms of the oxidase with porphyrin cytochrome c have been followed as functions of ionic strength; this behaviour has been compared with that of the resting oxidase [Kornblatt, Hui Bon Hoa and English (1984) Biochemistry 23, 5906-5911]. All forms of the cytochrome oxidase studied bind one porphyrin cytochrome c per 'functional' cytochrome oxidase (two heme a); it appears as though porphyrin cytochrome c and cytochrome c compete for the same site on the oxidase. The resting enzyme binds cytochrome c 8 times more strongly than porphyrin cytochrome c; the reduced enzyme, in contrast, binds the two with almost equal affinity. In all three cases, resting, pulsed and reduced, the heme-to-porphyrin distance is estimated to be about 3 nm. The tight-binding complexes formed between cytochrome oxidase and porphyrin cytochrome c can be dissociated by salt. Debye-Hückel analysis of salt titrations indicate that the resting enzyme and the reduced enzyme are similar in that the product of the interaction charges on the two proteins is about -14. The product of the charges for the pulsed enzyme is -25, indicating that on average another positive and negative charge take part in the interaction of the two proteins. While there is one tight binding site for cytochrome c per two heme a, cytochrome c is able to 'communicate' with four heme a. In the absence of cytochrome c, electron transfer from tetramethylphenylenediamine to the oxidase to oxygen results in the conversion of the resting form to the 'oxygenated'; in the presence of cytochrome c, the same electron transfer results in the appearance of the 'pulsed' form. Cytochrome c titrations of the enzyme show that a ratio of only one cytochrome c to four heme a is sufficient to convert all the oxidase to the 'pulsed' form. Porphyrin cytochrome c, like cytochrome c, catalyzes the same conversion with the same stoichiometry. The binding data and salt effects indicate that major structural alterations occur in the oxidase as it is converted from the resting to the partially reduced and subsequently to the pulsed form.

Aerobiosis↗
PubMed1985

Effects of polyhalogenated aromatic compounds on porphyrin metabolism.

Heme production is a vital metabolic process that occurs in the bone marrow and liver. Porphyrins are unused by-products of this biosynthetic process and normally occur in urine and other body fluids in low concentrations. Various disorders can disrupt the heme biosynthetic process, causing greater quantities of porphyrins in urine. The porphyrias are a group of diseases characterized by excessive porphyrins and other precursors in urine. Porphyrias may be either hereditary or acquired through exposure to certain drugs or chemicals. Porphyria cutanea tarda (PCT) is the disease associated with exposure to polyhalogenated aromatic compounds. The urinary porphyrin pattern is of great value in diagnosing PCT and defining the etiology of the disease. As this liver disease from chemical damage develops, the urinary pattern progressively changes. With the development of a rapid and sensitive high-performance liquid chromatography analysis, urinary porphyrin patterns can be easily monitored. All free porphyrin acids can be quantitatively analyzed in less than 15 min. In our studies of groups exposed to porphyrinogenic chemicals, we have not observed clear differences in the urinary porphyrin patterns of cases when compared with carefully selected controls. In animal studies, however, PCT was clearly associated with polybrominated biphenyl exposure. Future evaluation of the utility of urinary porphyrin patterns as a diagnostic tool will require a cohort that has received a recent, well-documented exposure and a comparable control population. Assay of erythrocyte uroporphyrinogen decarboxylase activity will also be needed to define the form of the PCT.

Animals↗
PubMed1997

Porphyrins preferentially accumulate in a melanoma following intravenous injection of 5-aminolevulinic acid.

Systemically, as opposed to topically, administered 5-aminolevulinic acid (ALA) is of increasing interest for photodynamic therapy (PDT) because of more selective and more homogeneous accumulation of porphyrins in neoplastic tissues. This study investigates the profile and the time course of porphyrin metabolites in various tissues following intravenous injection of ALA (0.5 g/kg body weight) into hamsters bearing an amelanotic melanoma (A-Mel-3). ALA injection led to maximum levels of ALA and porphyrins in erythrocytes after 45 min. In tissues, maximum porphyrin levels were detected after 45 min (tumor), 4 h (skin, kidney), and 24 h (liver). Sixfold higher porphyrin levels were observed in tumors as compared to surrounding normal skin at 45 min. Predominant porphyrin metabolites were protoporphyrin (tumor, skin, liver, kidney), coproporphyrin (tumor) and highly carboxylated porphyrins (tumor, skin, kidney). These data suggest optimum efficacy of light irradiation in systemic PDT with ALA within the first two hours after injection. Tumor-specific ALA metabolism yields protoporphyrin and coproporphyrin as the prevailing porphyrin metabolites.

Aminolevulinic Acid↗
PubMedDate not supplied

Photoinactivation of hepatitis A virus by synthetic porphyrins.

Porphyrins are photosensitizers and may be applicable in situations where viral inactivation is required, as for in vitro inactivation of nonenveloped viruses in blood components or in other aqueous media. No study has examined the efficacy of porphyrin inactivation on human pathogens such as hepatitis A virus (HAV) in plasma or other liquids. Experiments were conducted to evaluate the effect of synthetic porphyrins on HAV in porphyrin-containing human plasma and phosphate-buffered saline exposed to long-wavelength (365 nm) UV light. Inactivation of bacteriophage MS2 (MS2) also was determined in some trials. Solutions containing cationic, anionic or amphiphilic porphyrins irradiated with an average light dose of 4.3 J/cm(2) for 90 min resulted in >3 log(10) (>99.9%) to >4 log(10) (>99.99%) inactivation of both HAV and MS2. Viral inactivation may have been greater than observed because the limits of detection of the assay had been reached. Under ambient lighting conditions, none of the porphyrins was mutagenic in the Ames assay and only the congener with the longest chain-length, tetrakis (N-[n-hexadecyl]-4-pyridiniumyl) porphyrin, was appreciably toxic to mammalian cells. Disinfection by photoactivated synthetic porphyrins therefore can offer an effective and relatively safe approach to removal of nonenveloped viruses from aqueous media.

Hepatitis A virus↗
PubMed2001

Effect of hyperprolactinemia induced by pituitary grafts or castration on porphyrin content of the mouse Harderian gland.

The histology and porphyrin concentrations of Harderian glands and plasma prolactin levels were examined in B6C3F1 mice castrated or isografted with pituitaries in combination with the administration of bromocriptine (2-bromo-á-ergocryptine), a potent suppressor of prolactin. Four pituitaries were transplanted underneath the bilateral kidney capsules of each mouse. Furthermore, we investigated Harderian porphyrins and plasma testosterone levels in mice that were castrated or treated with neuroleptic butyrophenone (timiperone), a potent accelerator of prolactin, and treated concurrently with bromocriptine. Light microscopically, pituitary grafts increased the concretion of porphyrin pigments within the Harderian gland lumina. Pituitary grafts or castration increased both Harderian porphyrin concentrations and plasma prolactin levels compared with the intact control mice. In pituitary-grafted or castrated mice, bromocriptine distinctly prevented the rise in both porphyrins and prolactin levels. Administration of butyrophenone did not result in any marked change in testosterone levels, although Harderian gland porphyrins were significantly increased. The present results indicate that in mice prolactin stimulates the porphyrin production of the Harderian gland and has an important role in the regulation of Harderian gland porphyrins.

Animals↗
PubMed2005

[The photodynamic therapy effect of a new cationic porphyrin on human laryngeal cancer Hep-2 cell in vitro].

OBJECTIVE: To investigate the photodynamic therapy (PDT) effect of a new kind of cationic porphyrin on human laryngeal cancer Hep-2 cell in vitro. METHOD: A new cationic porphyrin (5-(4-methoxycarbonylphenyl)-10, 15, 20-tris(4-N-methylpyridiniumyl)porphyrin triiodide ) was synthesized. The Hep-2 cells were treated with three different concentrations of porphyrin (10(-7) mol/L, 10(-6) mol/L, 10(-5) mol/L) followed by irradiation of different visible light (0, 0.5, 1.0, 1.5, 2.0 h). MTT and TUNEL were applied to measure the inhibitory effect of porphyrin on the Hep-2 cells growth, inhibitory rate and induced apoptosis rate. RESULT: Under definite condition, the cantionic porphyrin concentrations had a significant inhibitory effect and induced apoptosis effect. The effect depended greatly on the doses of the concentration and the time of irradiation of light. At the highest concentration of porphyrin (10(-5) mol/L), the growth inhibitory rate were 1.18%, 35.21%, 58.59%, 70.42%, 84.34% respectively and the apoptosis rate were 3.30% +/- 0.29%, 29.41% +/- 2.12%, 32.30% +/- 2.26%, 34.52% +/- 3.11% in different visible light (0.05, 1.0, 1.5, 2.0 h), respectively. Under high irradiation energy, it can causesome Hep-2 cells death directly. CONCLUSION: Porphyrin has a distinctive killing effect on Hep-2 cells and correlated with the doses and the irradiation time.

Apoptosis↗
PubMedDate not supplied

Analysis of spectral changes in isotopically substituted porphyrins adsorbed on melanin surfaces by solid-state carbon-13 nuclear magnetic resonance spectroscopy.

Two synthetic, water-soluble porphyrins, tetra-4N-methyl-pyridyl porphyrin (T4NMPyP) and tetra-N,N,N-trimethylanilinium porphyrin (TMAnP), and their indium(III) complexes have been isotopically substituted for evaluation by solid-state NMR of their adsorption to melanin. Methyl carbons on the pyridyl and anilinium nitrogens on the periphery of the porphyrin are one site of substitution; the four equivalent meso carbons in the porphyrin ring are the second. Chemical shifts and line widths of the carbon resonances in the bulk porphyrins change after they are adsorbed on synthetic and natural melanins. These changes may be related to the predominant binding interactions involved in the adsorption process and suggest that chemisorption, involving strong interactions comparable to chemical bonds, occurs between charged groups in both ligand and substrate. Inhomogeneous line broadening of the resonances implies that variations in binding exist, which is in keeping with the known heterogeneous nature of the melanin polymer and the different steric demands of the porphyrin ligands. These solid-phase experiments illustrate the promise of NMR for elucidating information about the binding of soluble molecules to insoluble and structurally irregular biopolymers. Furthermore, they represent the first spectroscopic probe of the binding of cationic molecules to the biopolymer melanin in the solid state. Coupled with results from molecular modelling, they indicate that cationic porphyrins bind to melanin at similar sites.

Binding Sites↗
PubMed1987

[Clinical medicine of disorders of porphyrin metabolism in man].

Porphyrin metabolism disorders are grouped into three classes. 1) Hereditary porphyrias including those caused by an inherited deficiency in one of the enzymes responsible for porphyrin synthesis. 2) Secondary porphyrias: well defined clinical situations due to disturbed porphyrin metabolism caused by a variety of toxic substances or drugs or secondary to other pathological conditions. 3) porphyrin metabolism disorders as concomitant featured of certain types of poisoning or particular pathologies. This is followed by a brief description of porphyrin synthesis and the enzymes involved in it, and the distribution of porphyrins and their precursors in certain tissues and biological materials. Hereditary porphyrins are treated individually and not classified since all the classification systems proposed are open to criticism. However the value of grouping acute intermittent porphyria, hereditary coproporphyria, variegated porphyria and the porphyria caused by PBG-synthetase deficiency under "acute porphyrias" is recognised since all involve acute attacks with similar symptoms and prognoses, all are triggered by the same factors and all are treated in the same way. The various forms of hereditary porphyrias are grouped into 3 main categories: a) acute attacks featuring abdominal colics and signs of distress on the cerebral and peripheral nervous systems; b) skin alteration due to photosensitisation; c) haemolytic anaemia. Treatment is divided into preventive, symptomatic and aetiopathogenic. The individual hereditary porphyrias are then examined. The secondary porphyrias examined include lead poisoning, porphyria of the skin caused by hexachlorobenzene, subacute or chronic tyrosinaemia and acute intermittent porphyria caused by carbamazepine. Finally the porphyrin metabolism disorders concomitant with other diseases are examined including those encountered in anaemia, liver disease, dermatological conditions and infections and conditions caused by drugs and toxic substances.

Chemical Phenomena↗
PubMed1987

Porphyrin studies in chronic renal failure patients on maintenance hemodialysis.

Porphyrin studies were performed on 85 chronic renal failure patients on maintenance hemodialysis. Free erythrocyte porphyrins were elevated in 70% of patients, and a significant positive correlation between erythrocyte porphyrin and serum aluminium was found. Although plasma porphyrins were elevated in 58% of our patients, the elevated heptacarboxylic fraction invariably seen in porphyria cutanea tarda (PCT) was not present in the hemodialyzed patients. Total urine and fecal porphyrins were low, due to a marked decrease in the coproporphyrin and dicarboxylic fractions, respectively. An unequivocal diagnosis of PCT was made in 1 hemodialysis patient whose biochemical findings included an extremely high total plasma porphyrin with a large heptacarboxyl-porphyrin fraction. We found no biochemical evidence for any trend towards PCT in the remaining hemodialysis patients. The porphyrin results on a subgroup of hemodialysis patients with blisters or a history of blisters on sun-exposed skin were similar to those of the hemodialysis patients without blisters.

Aluminum↗
PubMed1986

Porphyrin content of the cysticercus of Taenia solium.

The strong red fluorescence of the cysticercus of Taenia solium depends on the presence of several porphyrins in the vesicular fluid of the parasite: probably protoporphyrin IX, coproporphyin I or III, and 2 decarboxylated porphyrins intermediate between uroporphyrin and coproporphyrin. Cyst porphyrins associated to form conglomerates of high molecular weight that dissociated in acid solutions and were not antigenic themselves nor associated with antigenic molecules. An appreciable fraction of the porphyrins was capable of undergoing oxidation and reduction, indicating that some of the porphyrins were complexed with metal ions. The metabolic basis for the accumulation of porphyrins is unknown. Preliminary results suggest that conditions deleterious to the cysticercus cause release of porphyrins so that the appearance of porphyrins in the cerebrospinal fluid of neurocysticercotic patients may prove useful in monitoring therapeutic attacks on the parasite.

Animals↗
PubMed1985

[Basic study for cancer therapy with porphyrin derivatives and pheophorbide derivatives].

The properties of Porphyrin and Pheophorbide derivatives with cyclic tetrapyrrole structure have a specific character to accumulate selectively in tumor tissues and destruct tumor cells by photodynamic action. Recently, Photoradiation therapy of cancer with Porphyrin derivatives has put into practice, but its indication is very limited. We examined fundamentally on tumor tissue affinity of various Porphyrin and Pheophorbide derivatives, aiming at expanding therapeutic indication and application. As materials we used 73 derivatives in total, including 14 Porphyrin derivatives, 32 Pheophorbide derivatives, 17 Porphyrin metal complex and 10 Pheophorbide metal complex, and examined about the relation between their side branches and their tumor tissue affinity by N2-pulsed Laser spectrofluorometry, using tumor-bearing Golden Hamster. Furthermore, we investigated substances connected with Hematoporphyrin derivatives (HPD) in tumor cells. As a result, we had the following conclusions. N2-pulsed Laser spectrofluorometry is useful for analysis of Porphyrin and Pheophorbide derivatives in vivo. In Porphyrin derivatives, those with dimer structure and acetyl radical have higher tumor tissue affinity than those without such structures. Existence of OH radical and dimer structure is dispensable for tumor tissue affinity of Pheophorbide derivatives. OH radical in Porphyrin metal complex and acetyl radical in Pheophorbide metal complex are important factors for tumor tissue affinity of them. It is suggested that Hematoporphyrin derivatives (HPD) in vivo combine with protein in tumor cells.

Animals↗