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PubMed1992

Comparison of porphyrin content in the cortex and medulla of the kidneys and adrenals of patients dying from chronic circulatory insufficiency.

Taking into account a correlation between the metabolism of porphyrins and hormones, and especially the metabolic interactions between the kidneys and adrenals, preliminary pilot studies were carried out on porphyrins in the kidneys and adrenals, separately in the cortex and in the medulla of these organs. The material was taken from 11 men and 8 women dying from circulatory insufficiency with vasculogenic renal fibrosis, and without changes in the adrenals. In all cases the concentration of porphyrins was much higher in the adrenals than that in the kidneys, while the content of uro-, copro-, and protoporphyrin was always higher in the adrenal medulla then that in the cortex. Discussing the results obtained the author suggest a correlation between disturbances of the reno-adrenal feedback, and an extremely increased concentration of porphyrins in the adrenal medulla which could be caused mainly by connections between the metabolism of catecholamines and porphyrins.

Adrenal Cortex↗
PubMed2003

Photodynamic effects of two water soluble porphyrins evaluated on human malignant melanoma cells in vitro.

Two water soluble porphyrins: meso-tetra-4-N-methylpyridyl-porphyrin iodide (P1) and 5,10-di-(4-acetamidophenyl)-15,20-di-(4-N-methylpyridyl) porphyrin (P2) were synthesised and evaluated in respect to their photochemical and photophysical properties as well as biological activity. Cytotoxic and phototoxic effects were evaluated in human malignant melanoma Me45 line using clonogenic assay, cytological study of micronuclei, apoptosis and necrosis frequency and inhibition of growth of megacolonies. Both porphyrins were characterised by high UV and low visible light absorptions. Dark toxicity measured on the basis of the clonogenic assay and inhibition of megacolony growth area indicated that P1 was non-toxic at concentrations up to 50 microg/ml (42.14 microM) and P2 at concentrations up to 20 microg/ml (16.86 microM). The photodynamic effect induced by red light above 630 nm indicated that both porphyrins were able to inhibit growth of melanoma megacolonies at non-toxic concentrations. Cytologic examination showed that the predominant mode of cell death was necrosis.

Antineoplastic Agents↗
PubMed1989

Oxidative effects of heme and porphyrins on proteins and lipids.

Heme and porphyrins catalyze the formation of various reactive oxygen species under widely different conditions. Porphyrins are potent photosensitizers capable of transferring the energy of their excited state to oxygen, forming 1O2. Heme, by virtue of its iron content, is not a photosensitizer, but it can react with H2O2 forming reactive oxygen intermediates whose nature depends on the oxidation state of the iron. Ferric heme gives rise to a porphyrin cation radical, while ferrous heme catalyzes the formation of OH.. The reactive species formed by heme and porphyrins oxidize susceptible functional groups on protein and lipid components of membranes as well as serum and cytosolic proteins. Oxidation of membrane-bound proteins occurs independently of lipid peroxidation and it is characterized by extensive cross-linking, which takes place subsequent to amino acid oxidation. Serum and cytosolic proteins that bind and may transport heme and porphyrins are of special interest since they can modulate their toxicity by affecting their availability and reactivity. In addition, these proteins are particularly susceptible to oxidation, especially by heme, due to their proximity to the oxidizing species that are formed.

Animals↗
PubMed1989

Interaction of porphyrins and metalloporphyrins with nucleic acids.

Differences in the interpretation of the details of the binding of porphyrins and metalloporphyrins to nucleic acids do exist, in part arising from the fact that different experimental techniques require different experimental conditions. For example, uv/vis absorption and CD spectroscopy use mumol/L and 10 to 100 mumol/L concentrations of drug and polymer respectively; whereas NMR uses mmol/l concentrations, increasing the likelihood of DNA aggregation. Differences in solvent conditions can have a profound effect on binding; changes in binding mode with changes in ionic strength have been observed for two of the porphyrins studied. At high levels of drug load the nucleic acid conformation may be changing and/or new modes of binding may become important. Thus, care must be taken when comparing data at different experimental conditions. At the same time that these various complexities for binding make comparison difficult it is precisely because of such complexities that these porphyrins are such sensitive probes of nucleic acid structure and dynamics. It may well be the diversity of binding of these porphyrins that will provide a variety of avenues for therapeutic strategies. It is certainly true that obtaining a complete binding picture for these porphyrins will require extended studies using a variety of techniques and experimental conditions.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1989

The effect of chlorinated chemicals on porphyrin metabolism--the synergistic effect with chlorinated chemicals and low concentrations of griseofulvin.

The synergistic effect of chlorinated chemicals and 0.1% griseofulvin on porphyrin metabolism was investigated. Feeds containing 0.1% 4-chloro-m-cresol, 0.1% cumarone or 0.25% trichloroacetic acid with or without 0.1% griseofulvin were given to dd-y strain mice respectively. The treatments were continued for 10 to 450 days, after which coproporphyrin and protoporphyrin in the erythrocytes and liver were analyzed. In the 0.1% griseofulvin alone group, protoporphyria was induced in 6 of 55 dd-y strain mice, although the other 49 mice did not show any abnormal porphyrin metabolism and the severity of the protoporphyria was mild in the 6 mice. In the 4-chloro-m-cresol group, a slight elevation of erythrocytic porphyrins was seen, but the difference was not statistically significant. Elevation of the hepatic porphyrins was not seen. Trichloroacetic acid and cumarone did not influence porphyrin metabolism, and also there was no synergistic effect of griseofulvin on porphyrinopathy. These results suggest that the three chemicals selected in this study are not capable of inducing porphyrinopathy.

Animals↗
PubMed1978

[Disorder of porphyrin metabolism in thallium intoxication (author's transl)].

A 19-year old male ingested in suicidal attempt 750 mg of thallium. He developed the characteristic symptoms of thallium intoxication. During the acute phase the urinary excretion of porphyrins and porphyrin precursors was largely increased. The percentage distribution of the individual metabolites of heme synthesis revealed a preponderance of kopro- and uroporphyrin. This constellation (kopro- greater than uro- greater than tricarboxylic porphyrin) differs appreciably from that one in lead intoxication. The observation of increased urinary excretion of porphyrins and their precursors in a possibly particular spectrum in thallium intoxication is of special interest for differential-diagnostic reasoning. In each case of a toxic disorder of porphyrin metabolism thallium intoxication ought to be considered a possible cause.

Adrenergic beta-Antagonists↗
PubMed1978

Resonance Raman studies on the ligand-iron interactions in hemoproteins and metallo-porphyrins.

The resonance Raman spectra (RRS) were measured for various hemoproteins, as well as for free hemes, and analysed in terms of the interactions between the porphyrin ring and the heme iron and between the axial ligand and the heme iron. To establish vibrational assignments, the RRS of metallo-octae-thylporphyrin (M(OEP)), its 15N substituted and meso-deuterated derivatives were measured. It was found that the Raman line corresponding to the oxidation state marker of hemoproteins involves appreciable displacement of the pyrrolic nitrogen atoms toward metal ion but not that of methine bridges and that the frequencies of methine-bridge CC stretching vibrations are altered by the conjugation interaction between the porphyrin ring and the metal ion present. The prominent Raman lines of Ni(OEP) were assigned on the basis of the normal coordinate analysis. The Raman spectra of heme a bis-imidazole complex (Fe(A)(Im)2) in the presence of cyanide changed when pH was reduced to neutral. It implied formation of cyanhydrin at the peripheral formyl group of heme a. The Fe(A)(Im)2 formed an addition compound with NaHSO3 in a neutral solution but the added NaHSO3 was eliminated when the heme iron was reduced. The Raman spectra of hemoproteins were classified into four groups on the basis of the relative intensities and frequencies of the four key bands. It demonstrated the existence of two kinds of ferrous low-spin states. The difference between the two species was attributed to the difference in the nature of chemical bond between the heme iron and its sixth ligand (L). The Fe-L bonds of ferrous low-spin molecules in Groups A and C are mainly associated with the dz2(Fe)-lone pair and dz(Fe)-II(L) interactions, respectively. This interpretation of the Raman spectra appears consistent with the experimental facts that the ferrous low-spin molecules in Group C photodissociate upon illumination of light at the Soret band and also that the internal stretching frequencies of the sixth ligand are shifted to lower frequency upon coordination to the heme iron. The frequency of the oxidation state marker of reduced cytochrome P-450 (P-450cam) was unusually low in comparison with those of other hemoproteins. It was ascribed to delocalization of electrons from the thiolate anion to the porphyrin II*(ring) orbital through the pi-type molecular orbital (Eq.3). The RRS of reduced P-450cam.metyrapone adduct was quite close to that of reduced cytochrome b5. In conclusion, the Raman frequencies of hemoproteins may depend primarily upon the amount of electrons delocalized to the II* orbital of the porphyrin ring. The coordination of lone-pair electrons of the axial ligand to the iron dz2 orbital yields bond energy but scarcely affects the Raman frequencies. If the pi orbital of the axial ligand interacts with the iron dpi orbital, it perturbs the delocalization of the dpi(Fe) electrons to the II*(ring) orbital of porphyrin ring and thus affects the Raman frequencies.

Chemical Phenomena↗
PubMed1988

Characterization of porphyrin interactions with peripheral type benzodiazepine receptors.

We have examined organ and species variations in interactions of porphyrins with peripheral-type benzodiazepine receptors and explored structure-activity requirements for porphyrin-receptor interactions. Whereas potency of the benzodiazepine RO5-4864 varies several orders of magnitude in competing for receptors in different organs and species, effects of porphyrins and the isoquinoline carboxamide PK11195 are relatively constant. The structural requirements determining porphyrin affinity for benzodiazepine binding sites are fairly strict. The most potent porphyrins are those with prominent physiological functions.

Animals↗
PubMed1986

Selective in vivo tumor localization of uroporphyrin isomer I in mouse mammary carcinoma: superiority over other porphyrins in a comparative study.

Twenty-eight porphyrins were evaluated for tumor localization as delineated by fluorescence using a transplantable KHJJ mammary carcinoma in BALB/c mice as the tumor model. Five of the 28 porphyrins were found to localize and of these, one, i.e., uroporphyrin I (UROP I), showed a higher tumor:skin ratio than any of the others; moreover, as no measurable UROP I was present in the gut, the tumor:intestinal porphyrin ratio under the conditions of assay was infinity. Because hematoporphyrin derivative (HPD), a complex mixture of porphyrins has been studied extensively as a tumor localizer, we compared HPD with UROP I at differing doses (2-40 mg/kg) and at different times (3-96 h) following i.v. administration. Dose response curves showed tissue levels of porphyrin to plateau out at doses above 20 mg/kg. Peak tumor HPD and UROP I levels attained 6-18 h after i.v. administration (40 mg porphyrin/kg) were comparable, but tumor retention of HPD over the ensuing 96 h was higher. The ratio of UROP I in tumor compared to skin was significantly greater throughout the period of observation. At all times, no UROP I was detectable in gastrointestinal mucosa. At differing doses (10-40 mg/kg), the tumor:skin ratio for HPD ranged from 1.47-1.85, and for UROP I from 6.06-12.33. As a function of time (6-72 h), the tumor:skin ratios respectively were 1.03-2.38, and 11.9 to infinity. At all times, the tumor:colon mucosa ratio at different doses for HPD approached 1 and for UROP I was infinity. We conclude that the greater specificity of tumor uptake by UROP I and its lack of retention by gut mucosa warrants further study to determine its potential clinical application as a diagnostic marker, particularly for early mucosal cancer, and in photoradiation therapy.

Animals↗
PubMed1988

The effects of age on the structure and porphyrin synthesis of the harderian gland of the female golden hamster.

The effects of age on structure and porphyrin synthesis were examined in the Harderian gland of the female golden hamster. An age range of 2-24 months was examined. Porphyrin enzyme activity reached a peak at 6 months and then declined; the porphyrin content of the gland (as determined both by biochemical assay and by the number of visible porphyrin accretions) also declined from 6 months. Mast cells, found in large numbers in the actively synthesising female gland, declined with age. Conversely, tubule epithelial cells with large lipid vacuoles (Type II cells--characteristic of the non-synthesising male gland) increased in frequency. There was considerable evidence of degenerative changes in gland structure with age. These included thinning of the tubule walls, invasion of the tubule lumen by neutrophils and the appearance of porphyrin stores within the interstitium of the gland. The latter were either large accretions surrounded by foreign body giant cells, or smaller deposits within individual free macrophages. Changes may be the result of ageing itself, of hormone insufficiency in post-reproductive senescence or inflammatory processes.

Aging↗
PubMed1988

Factors influencing fluorescence spectra of free porphyrins.

We recorded fluorescence excitation and emission spectra of uro- and coproporphyrin under different experimental conditions, to see how these conditions influence quantifications based on measurement of fluorescence intensity. We found that, for bands alpha and beta of the emission spectra and the main peak of the excitation spectra, fluorescence depends on pH and is minimal near pH 5 and near pH 7-7.5 for copro- and uroporphyrin, respectively. For band gamma of the emission spectra there was a constant decrease of fluorescence with increasing alkalinity of the solution. The intensity of porphyrin fluorescence also depends on ionic strength, reaching sharp maxima at 0.1 mol/L (for uroporphyrin) and 1 mol/L (for coproporphyrin). The organic mixture ethyl acetate:acetic acid (4:1 by vol), commonly used to extract porphyrins from biological samples, markedly diminishes the fluorescence of both porphyrins as compared with the same concentration of each porphyrin in aqueous acidic solvent. Furthermore, when we measured different ratios of uro:copro mixture at three distinct pHs and buffers, we found that at pH 10.5 (in carbonate buffer) the measured units of fluorescence depend only on total porphyrin concentration and not on the composition of the mixture.

Coproporphyrins↗
PubMed1986

Porphobilinogen deaminase and the synthesis of porphyrin isomers in the Dubin-Johnson syndrome.

Porphyrin synthesis was studied in a family of 9.3 of whom had the Dubin-Johnson syndrome (DJS). Subjects with DJS had modest increases in urinary porphyrin concentration with a marked increase in the series I isomer of coproporphyrin (tetracarboxylic) as well as in the octa-, hepta-, hexa- and penta-carboxyl porphyrins. Activity of erythrocyte porphobilinogen deaminase (PBG-D) was also increased. Non-expressing carriers in the family had normal levels of urinary porphyrins but modest increases in both series I isomer accumulation and PBG-D activity. These results may provide a rationale for the altered synthesis of porphyrin in DJS.

Adolescent↗
PubMed1985

Rapid procedure for fecal porphyrin assay.

Hydrochloric acid extraction of feces in the presence of ether yields an extract suitable for spectrophotometric estimation of total porphyrin and for further separation by "high-performance" liquid chromatography (HPLC) or thin-layer chromatography. A total porphyrin reference interval of less than 200 nmol/g dry weight of feces was established from data on 106 normal subjects on an unrestricted diet. Total fecal porphyrin values in 11 porphyria cutanea tarda patients were considerably higher than given by the widely used Rimington method (respective means, 652 and 239 nmol/g dry weight). Our HPLC method for separation of porphyrin methyl esters on a silica column, with quantification by fluorescence, is described. HPLC separations performed on 23 porphyria cutanea tarda patients gave the following mean proportions of total fecal porphyrins: dicarboxylics 21%, coproporphyrin 9%, isocoproporphyrins 28%, pentacarboxylporphyrin 9%, hexacarboxylporphyrin 11%, heptacarboxylporphyrin 18%, and uroporphyrin 4%.

Chromatography, High Pressure Liquid↗
PubMed1982

The conformational transition of horse heart porphyrin c.

The heme iron of horse heart cytochrome c was selectively removed using anhydrous HF. The product, porphyrin c, exhibits the viscosity, far ultraviolet circular dichroic, and fluorescence properties characteristic for native cytochrome c. However, porphyrin c is more susceptible to denaturation by guanidine hydrochloride and by heat than is the parent cytochrome. All of the conformational parameters of porphyrin c exhibit a common reversible transition centered at 0.95 m guanidine hydrochloride at 23 degrees C and pH 7.0. Guanidine denatured porphyrin c refolds in two kinetic phases having time constants of 20 and 200 ms as detected by stopped flow absorbance or fluorescence measurement, with about 80% of the observed change in the faster phase. The kinetics of porphyrin c refolding are not significantly altered by increasing the viscosity of the refolding solvent 15-fold by addition of sucrose. We suggest that the folding of guanidine denatured cytochrome c is not a diffusion-limited process and that the requirement for protein axial ligation elicits the slow (s) kinetic phase observed in the refolding of cytochrome c.

Amino Acids↗
PubMedDate not supplied

[Suppression of singlet oxygen luminescence by porphyrins and metalloporphyrins].

The luminescene of 1O2 (1270 nm) has been observed upon illumination of air saturated solutions of different porphyrins and their complexes with Zn in CCl4. In solutions of Co-, Cu-, Ni- and Fe-porphyrins this luminescence has not been revealed. All the porphyrins studied have shown to quench 1O2, the rate constants of the "physical" and "chemical" quenching being measured. The physical way of quenching is found to be much more effective. The quenching activity of the pigments depends greatly on the presence and nature of the central metall atom incorporated into porphyrin (H2 less than Cu less than Zn less than Co approximately Ni approximately Fe) increases with hydrogenation of the semiisolated double bonds (porphyrins are less active than chlorins and bacteriochlorins).

Chemical Phenomena↗
PubMed1984

Urinary porphyrins in liver disease.

By use of quantitative thin-layer chromatography, urinary porphyrins were examined in 40 healthy volunteers, 38 patients with prophyria cutanea tarda (PCT), and 139 patients with various liver diseases. Significant elevations not only of coproporphyrin but also of some other porphyrins were found in many patients with liver disease. However, there was no evident relationship between porphyrin disturbances and functional or clinical findings, and all of these non-PCT patients who initially demonstrated intense uroporphyrinuria, when re-studied apparently had more normal porphyrin excretion. It seems, therefore, that whereas porphyrin estimations are useful in porphyrias, no clinically important conclusions can be drawn from urinary findings in patients with liver disease. The origin of defective haem biosynthesis in liver disease remains obscure. It can only be speculated that transient and reversible urocoproporphyrinuria may occur in patients with defective hepatic uroporphyrinogen decarboxylase activity who clinically and biochemically are not porphyric.

Adult↗
PubMed1983

[Nephrogenic anemia and porphyrin biosynthesis].

Porphyrin biosynthesis in erythrocytes, after incubation with delta-aminolevulinic acid (DALA) was studied in 180 patients with renal diseases. A decrease of porphyrin synthesis was confirmed as early as the compensated stage of the disease with normal hematological indices. With the advancement of the renal insufficiency the biosynthesis of porphyrin and porphobilinogen was progressively decreased, as well as the percentage of DALA used in porphyrins synthesis and the activity of porphobilinogen synthesis in erythrocytes, accompanied by a progressive deterioration of the hematological indices. The correlation between the functional state of the kidneys, the indices of porphyrins metabolism and hematological indices in the patients with chronic renal diseases is underlined.

Adolescent↗
PubMed1983

Liquid-chromatographic profiles of urinary porphyrins.

Information on changes in the urinary excretion pattern of porphyrins can be especially useful in the diagnosis of disorders of porphyrin metabolism. Most clinical laboratory procedures are designed for assay of uroporphyrin and coproporphyrin only, and in many cases even these are not cleanly separated. Hence, we developed a "high-performance" liquid-chromatographic procedure to separate and quantify all five urinary porphyrins--that is, those with four through eight carboxyl groups. Before chromatography, the porphyrins are isolated from other urinary components by two simple, rapid pretreatment steps, then injected into the chromatograph in nonesterified form. They are separated and eluted with a step gradient of methanol/phosphate buffer, pH 3.0, in which the methanol content is first 650, then 850 mL/L. As little as 1 ng of eluted porphyrins can be measured fluorometrically. Analytical recovery of coproporphyrin is virtually 100% and of uroporphyrin 75-80%. CVs are about 10% for coproporphyrin at 70 micrograms/L and 20-40% for uroporphyrin at 8 micrograms/L.

Chromatography, High Pressure Liquid↗