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1
Hindmarsh, J. Thomas, Linda Oliveras e Donald C. Greenway. "Plasma Porphyrins in the Porphyrias". Clinical Chemistry 45, n. 7 (1 luglio 1999): 1070–76. http://dx.doi.org/10.1093/clinchem/45.7.1070.
Testo completoAbstract (sommario):
Abstract Background: As an aid in the diagnosis and management of porphyria we have developed a method to fractionate and quantify plasma porphyrins and have evaluated its use in various porphyrias. Methods: We used HPLC with fluorometric detection to measure plasma concentrations of uroporphyrin I and III, heptacarboxyl III, hexacarboxyl III, pentacarboxyl III, and coproporphyrin I and III. We studied 245 healthy subjects, 32 patients with classical porphyria cutanea tarda (PCT), 12 patients with PCT of renal failure, 13 patients with renal failure, 8 patients with pseudoporphyria of renal failure, 3 patients with acute intermittent porphyria, 5 patients with variegate porphyria, 5 patients with hereditary coproporphyria, and 4 patients with erythropoietic protoporphyria. Results: Between-run CVs were 5.4–13%. The recoveries of porphyrins added to plasma were 71–114% except for protoporphyrin, which could not be reliably measured with this technique. Plasma porphyrin patterns clearly identified PCT, and its clinical sensitivity equaled that of urine porphyrin fractionation. The patterns also allowed differentiation of PCT of renal failure from pseudoporphyria of renal failure. Conclusions: The assay of plasma porphyrins identifies patients with PCT and appears particularly useful for differentiating PCT of renal failure from pseudoporphyria of renal failure.
2
Puzikova, А. I., Е. А. Litvin, D. А. Kildyushkin e А. Е. Druy. "Application of high-performance liquid chromatography in porphyrias diagnostics". Pediatric Hematology/Oncology and Immunopathology 20, n. 3 (8 ottobre 2021): 140–44. http://dx.doi.org/10.24287/1726-1708-2021-20-3-140-144.
Testo completoAbstract (sommario):
Porphyrias are distinguished by the stage of heme synthesis at which a failure occurs, leading to the accumulation of intermediate products – porphyrins. Due to the low specificity of clinical manifestations of porphyria and the latent course of the disease, their timely diagnosis is difficult. This article substantiates the effectiveness of high-performance liquid chromatography method in the determination of porphyrins. The method is suitable for porphyrin determination in urine, blood and feces of patients. Examples of its work are shown.
3
Stölzel, Ulrich, Thomas Stauch e Ilja Kubisch. "Porphyrien". Der Internist 62, n. 9 (29 giugno 2021): 937–51. http://dx.doi.org/10.1007/s00108-021-01066-1.
Testo completoAbstract (sommario):
ZusammenfassungPorphyrien werden durch Enzymdefekte der Hämbiosynthese hervorgerufen und anhand spezifischer biochemischer Muster von Porphyrinen und deren Vorläufern in Urin, Stuhl und Blut diagnostiziert. Das jeweilige Muster der akkumulierten Porphyrine, Vorläufer und Derivate ist verbunden mit der klinischen Ausprägung, die abdominale, neurologische, psychiatrische, endokrine, kardiovaskuläre Symptome, Leberschaden und/oder Lichtempfindlichkeit der Haut umfassen kann. Klinisch werden akute und nichtakute Porphyrien unterschieden. Bei symptomatischen (klinisch aktiven), akuten hepatischen Porphyrien – hierzu gehören akute intermittierende Porphyrie, Porphyria variegata, hereditäre Koproporphyrie und Doss-Porphyrie – kommt es aufgrund einer Regulationsstörung zur Kumulation der Porphyrinvorläufer 5‑Aminolävulinsäure und Porphobilinogen. Bei den nichtakuten Formen – u. a. Porphyria cutanea tarda, erythropoetische und X‑chromosomale Protoporphyrie sowie kongenitale erythropoetische Porphyrie – führen akkumulierte Porphyrine zu Lichtempfindlichkeit (Fotodermatose) und mitunter auch zu schweren Leberschäden. Zur Therapie der Porphyrien stehen sowohl bewährte und sichere als auch innovative Optionen zur Verfügung.
4
Hindmarsh, J. T. "The porphyrias: recent advances." Clinical Chemistry 32, n. 7 (1 luglio 1986): 1255–63. http://dx.doi.org/10.1093/clinchem/32.7.1255.
Testo completoAbstract (sommario):
Abstract Recent research has elucidated several of the hitherto poorly understood steps in heme synthesis. This review describes this metabolic pathway and pinpoints the enzymatic blockages in the various porphyrias. Recent advances in the understanding of the etiology of porphyria cutanea tarda are discussed, as are the abnormalities of porphyrin metabolism seen in chronic renal failure and in lead poisoning. An outline is given of the clinical and biochemical abnormalities seen in the porphyrias. Included is an algorithm to aid in the differential diagnosis of these diseases, and a brief review of the new analytical techniques available for the identification and quantification of porphyrins and their precursors in body fluids.
5
Carson, R. W., E. J. Dunnigan, T. D. DuBose, D. E. Goeger e K. E. Anderson. "Removal of plasma porphyrins with high-flux hemodialysis in porphyria cutanea tarda associated with end-stage renal disease." Journal of the American Society of Nephrology 2, n. 9 (marzo 1992): 1445–50. http://dx.doi.org/10.1681/asn.v291445.
Testo completoAbstract (sommario):
Plasma porphyrin levels are markedly increased in patients with porphyria cutanea tarda (PCT) associated with end-stage renal disease. Conventional hemodialysis (CHD) with lower blood flow rates (less than 250 mL/min) and cuprophan or cellulose acetate membranes is ineffective in removing significant amounts of porphyrins in this condition. Changes in plasma porphyrin levels and porphyrin clearances during hemodialysis with higher blood flow rates and more-permeable, high-efficiency cellulose acetate and high-flux polysulfone dialyzers were evaluated in a chronic hemodialysis patient with PCT and markedly elevated plasma porphyrins. The polysulfone membrane achieved significantly better fractional porphyrin removal (P = 0.02) and porphyrin clearances (P less than 0.01) than did the high-efficiency cellulose acetate membrane. After conversion from maintenance CHD with a standard cellulose acetate dialyzer to a 4-wk period of high-flux hemodialysis (HFHD) with a polysulfone dialyzer, predialysis plasma porphyrins fell by 37%. After returning to CHD, plasma porphyrins returned to the higher prestudy levels. These observations suggest that HFHD with more permeable membranes and higher blood flow rates removes porphyrins more effectively than does CHD. HFHD may be a useful adjunct to other measures used in treating dialysis patients with PCT.
6
Sooambar, Chloé, Vincent Troiani, Hongjin Qiu, Sunichi Fukuzumi, Lucia Flamigni, Régis Rein e Nathalie Solladié. "Chirality and spatially pre-organized multi-porphyrinoids". Journal of Porphyrins and Phthalocyanines 22, n. 04 (aprile 2018): 291–302. http://dx.doi.org/10.1142/s1088424618500396.
Testo completoAbstract (sommario):
We report herein that chiral and enantiopure compounds such nucleosides and peptides can pre-organize multi-porphyrinic systems and influence their properties. The first example given concerns star-shaped mutli-porphyrins with chiral and enantiopure nucleosidic linkers. If the configuration is indeed a star-shaped nanomolecule, it appears that the induced conformation is nothing as expected. The four peripheral Zn(II) porphyrins collapse over the free-base central one, inducing totally different photo-physical properties. Despite a minor expected light energy harvesting behavior, the principal capability of this system is to quench the collected light energy and convert it from radiative to non-radiative de-activation. The second example concerns polypeptides with pendant porphyrins. The peptidic backbone confers to the systems, after a certain degree of oligomerization, a 3[Formula: see text] right handed helical conformation which induces cavities within the multi-porphyrinc architecture, ready to welcome guests and render, for example, the complexation of C[Formula: see text] much easier. We thus have constructed novel organic photovoltaic systems using supramolecular complexes of porphyrin–peptide oligomers with fullerene clusters. The composite cluster OTE/SnO[Formula: see text] electrode prepared with (P(ZnP)[Formula: see text] C[Formula: see text], exhibits an impressive incident photon-to-photocurrent efficiency (IPCE) with values reaching as high as 56%. The power conversion efficiency of the (P(H[Formula: see text]P)[Formula: see text] C[Formula: see text] modified electrode reaches 1.6%, which is 40 times higher than the value (0.043%) of the porphyrin monomer (P(H[Formula: see text]P)[Formula: see text] [Formula: see text] C[Formula: see text] modified electrode. Thus, the organization approach between porphyrins and fullerenes with polypeptide structures is promising, and may make it possible to further improve the light energy conversion properties by using a larger number of porphyrins in a polypeptide unit.
7
Schoenfeld, N., e R. Mamet. "Interference of ofloxacin with determination of urinary porphyrins". Clinical Chemistry 40, n. 3 (1 marzo 1994): 417–19. http://dx.doi.org/10.1093/clinchem/40.3.417.
Testo completoAbstract (sommario):
Abstract The second-generation quinolone ofloxacin interferes with the screening test of porphyrins. We observed a 20-fold increase in the porphyrin concentration measured in urine of an ofloxacin-treated patient, compared with drug-free normal urine. Two other fluorinated 4-quinolones tested, norfloxacin and ciprofloxacin, had a less marked effect (a twofold increase), whereas the first-generation quinolone, nalidixic acid, did not affect the measured porphyrin concentration at all. The interference is probably due to the overlap in the emission fluorescence spectra of ofloxacin and urinary porphyrins at approximately 600 nm. To avoid a false-positive diagnosis of porphyria, we suggest using HPLC to separate ofloxacin (10-min retention time) from urinary porphyrins (which only start to elute at 12 min). Nonetheless, given a threefold increase in urinary porphyrins observed in the urine of an ofloxacin-treated patient, we also discuss a possible interference of the drug with the metabolism of porphyrins.
8
Wenceslau, Adriana C., Guilherme L. Q. C. Ferreira, Noboru Hioka e Wilker Caetano. "Spectroscopic studies of pyridil and methoxyphenyl porphyrins in homogeneous and Pluronic®-based nanostructured systems". Journal of Porphyrins and Phthalocyanines 19, n. 11 (novembre 2015): 1168–76. http://dx.doi.org/10.1142/s1088424615500996.
Testo completoAbstract (sommario):
Spectroscopic properties of Porphyrins TPyP (tetra(4-pyridil)porphyrin), TMPP (tetrakis(4-methoxypheny) porphyrin) and its zinc metaled derivatives porphyrins Zn-TPyP and Zn-TMPP respectively, were studied in homogeneous and micro heterogeneous systems, comprising nanostructured Pluronic® copolymeric micellar systems, as a promising drug delivery systems for the porphyrins investigated. Physico-chemical properties such as, hydrophobicity degree, self- aggregation in solvents of different polarities and water/ethanol mixtures (monofasic binary), as well as kinetics profile and isotherm binding, molecular organization, [Formula: see text] and relative localization in neutral micellar systems. The hydrophobic character was the key to relative drug location in the micellar systems. In homogenous solvents systems the porphyrins presented relatively high values of molar absorptivity and low values of [Formula: see text]. The K[Formula: see text] values obtained are modulated by the structure of porphyrins, state of aggregation, as well as, structure and macro molecular self-organization of copolymers. Fluorescence quenching studies have shown that porphyrins in F-127 are located in a less hydrophobic region than the porphyrins in P-123, which are located preferentially in a deeper micellar microenvironment. The zinc porphyrins showed high values of K[Formula: see text]. Thus, the association of the porphyrins with specific binding sites of micellar systems is strongly modulated by the presence of the metal coordinated to the porphyrinic ring.
9
Woolf, Jacqueline, Joanne T. Marsden, Timothy Degg, Sharon Whatley, Paul Reed, Nadia Brazil, M. Felicity Stewart e Michael Badminton. "Best practice guidelines on first-line laboratory testing for porphyria". Annals of Clinical Biochemistry: International Journal of Laboratory Medicine 54, n. 2 (19 gennaio 2017): 188–98. http://dx.doi.org/10.1177/0004563216667965.
Testo completoAbstract (sommario):
The porphyrias are disorders of haem biosynthesis which present with acute neurovisceral attacks or disorders of sun-exposed skin. Acute attacks occur mainly in adults and comprise severe abdominal pain, nausea, vomiting, autonomic disturbance, central nervous system involvement and peripheral motor neuropathy. Cutaneous porphyrias can be acute or chronic presenting at various ages. Timely diagnosis depends on clinical suspicion leading to referral of appropriate samples for screening by reliable biochemical methods. All samples should be protected from light. Investigation for an acute attack: • Porphobilinogen (PBG) quantitation in a random urine sample collected during symptoms. Urine concentration must be assessed by measuring creatinine, and a repeat requested if urine creatinine <2 mmol/L. • Urgent porphobilinogen testing should be available within 24 h of sample receipt at the local laboratory. Urine porphyrin excretion (TUP) should subsequently be measured on this urine. • Urine porphobilinogen should be measured using a validated quantitative ion-exchange resin-based method or LC-MS. • Increased urine porphobilinogen excretion requires confirmatory testing and clinical advice from the National Acute Porphyria Service. • Identification of individual acute porphyrias requires analysis of urine, plasma and faecal porphyrins. Investigation for cutaneous porphyria: • An EDTA blood sample for plasma porphyrin fluorescence emission spectroscopy and random urine sample for TUP. • Whole blood for porphyrin analysis is essential to identify protoporphyria. • Faeces need only be collected, if first-line tests are positive or if clinical symptoms persist. Investigation for latent porphyria or family history: • Contact a specialist porphyria laboratory for advice. Clinical, family details are usually required.
10
Perkins, S. L., e P. M. Johnson. "Loss of porphyrins from solution during analysis: effect of sample pH and matrix on porphyrin quantification in urine by "high-performance" liquid chromatography." Clinical Chemistry 35, n. 7 (1 luglio 1989): 1508–12. http://dx.doi.org/10.1093/clinchem/35.7.1508.
Testo completoAbstract (sommario):
Abstract We report the effect of sample matrix and pH on quantification of porphyrins by HPLC with fluorimetric detection. For aqueous solutions of pH less than 2.5, HPLC peak heights of the porphyrins increased with decreasing pH, reaching a plateau at pH less than 1.0. This loss of porphyrins from solutions with pH greater than 1.0 appeared to be due to a combination of microprecipitation and aggregation effects. No such "pH effect" was observed for urine samples supplemented with mixed-porphyrin standards. Addition of trace amounts of albumin to aqueous solutions also decreased these pH-related losses. These findings suggest a porphyrin-protein interaction that prevents microprecipitation and aggregation processes. We conclude that standard solutions of porphyrins for HPLC analysis should be prepared in a urine matrix. If aqueous solutions are used, then the pH must be adjusted to less than 1.0. Urine samples from normal individuals require only adjustment of pH to less than 2 before analysis; however, porphyric urines requiring dilution should be prepared with porphyrin-free urine diluent.
11
Lai, C. K., C. W. Lam e Y. W. Chan. "High-performance thin-layer chromatography of free porphyrins for diagnosis of porphyria". Clinical Chemistry 40, n. 11 (1 novembre 1994): 2026–29. http://dx.doi.org/10.1093/clinchem/40.11.2026.
Testo completoAbstract (sommario):
Abstract In this simple high-performance thin-layer chromatographic technique for evaluating porphyrin excretion, porphyrins rapidly extracted from urine or feces are separated on reversed-phase octadecylsilyl (C18)-bonded silica thin-layer chromatography plates. We observed > 12 distinct bands of different porphyrins by viewing the plates under long-wave ultraviolet light. Positive screening tests can readily be characterized by the relative fluorescence of various free porphyrins. The two patients presented in this paper are possibly the first two cases of porphyria cutanea tarda reported in Hong Kong Chinese.
12
Rose, I. S., G. P. Young, D. J. St John, M. C. Deacon, D. Blake e R. W. Henderson. "Effect of ingestion of hemoproteins on fecal excretion of hemes and porphyrins." Clinical Chemistry 35, n. 12 (1 dicembre 1989): 2290–96. http://dx.doi.org/10.1093/clinchem/35.12.2290.
Testo completoAbstract (sommario):
Abstract Stools from asymptomatic volunteers on diets containing red meat, whole blood, or high fiber were analyzed for their content of hemes and dicarboxylic (heme-derived) porphyrins by the "HemoQuant" assay, the "Hemoccult" test, and "high-performance" liquid chromatography (HPLC). In 49 subjects, ingestion of red meat increased HemoQuant-determined combined fecal heme plus dicarboxylic porphyrins by an average 375%; the contribution of heme-derived porphyrins to total fecal porphyrins increased from 37% to 78%. Of subjects on a red-meat diet, 27% passed stools with a porphyrin content suggestive of a porphyria, compared with only 4% on a red-meat-free diet. These increases were due largely to protoporphyrin and its derivatives pemptoporphyrin and deuteroporphyrin, all of which were present in feces as iron-free porphyrins and iron-ligated (heme) forms. Ingestion of blood had an effect similar to that of red meat, but ingestion of fiber had no effect. These effects of dietary and endogenous hemoproteins must be considered when such methods are used to test feces for occult blood or to test for excess fecal porphyrins as an indicator of a porphyria.
13
Richeter, Sébastien, Christophe Jeandon, Christian Sauber, Jean-Paul Gisselbrecht, Romain Ruppert e Henry J. Callot. "Preparation, mass spectrometry and electrochemical studies of metal connected porphyrin oligomers". Journal of Porphyrins and Phthalocyanines 06, n. 06 (giugno 2002): 423–30. http://dx.doi.org/10.1142/s108842460200052x.
Testo completoAbstract (sommario):
Oligomers built from metal ions and porphyrins bearing enaminoketones at the ring periphery were prepared. These dimers or trimers, where all porphyrinic rings are coplanar, show large interactions in the ground state between the individual porphyrin cores, as shown by their optical properties and electrochemical studies. In particular, a spectacular decrease of the HOMO-LUMO gap (with values as low as 1.32 eV) was observed for monomeric porphyrins metalated on the external sites. Along with standard analytical methods, APPI (Atmospheric Pressure PhotoIonization) mass spectrometry was found to be a very powerful tool to characterize these metal connected porphyrin oligomers.
14
Kaczynski, Jerzy, Göran Hansson e Sven Wallerstedt. "Increased Porphyrins in Primary Liver Cancer Mainly Reflect a Parallel Liver Disease". Gastroenterology Research and Practice 2009 (2009): 1–6. http://dx.doi.org/10.1155/2009/402394.
Testo completoAbstract (sommario):
Hepatic porphyries have been associated with an increased risk of primary liver cancer (PLC), which on the other hand may cause an increased porphyrin production. To evaluate the role of an underlying liver disorder we analyzed porphyrins in patients with hepatocellular carcinoma (HCC)(n=65), cholangiocellular carcinoma(n=3), or suspected PLC, which turned out to be metastases(n=18)or a benign disorder(n=11). None of the patients had a family history of porphyry or clinical signs of porphyry. Increased aminolevulinic acid or porphyrin values were common not only in patients with PLC (43%) but also in metastatic (50%) and benign (64%) liver disorders. The corresponding proportion for HCC patients with liver cirrhosis (55%) was higher(P<.05)than in those without cirrhosis (17%). We conclude that symptomatic porphyries are unusual in PLC, whereas elevated urinary and/or faecal porphyrins are common, primarily reflecting a parallel liver disease and not the PLC.
15
Thunell, S. "Porphyrins, porphyrin metabolism and porphyrias. I. Update". Scandinavian Journal of Clinical and Laboratory Investigation 60, n. 7 (gennaio 2000): 509–40. http://dx.doi.org/10.1080/003655100448310.
Testo completo
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Mukerji, S. K., N. R. Pimstone, S. N. Gandhi e K. T. Tan. "Biochemical diagnosis and monitoring therapeutic modulation of disease activity in an unusual case of congenital erythropoietic porphyria." Clinical Chemistry 31, n. 12 (1 dicembre 1985): 1946–51. http://dx.doi.org/10.1093/clinchem/31.12.1946.
Testo completoAbstract (sommario):
Abstract We describe the methodology used for quantifying and characterizing porphyrins in various tissues and in excreta, in the diagnosis and monitoring of the therapeutic modulation of biochemical disease activity in a 53-year-old white man who has a rare form of familial porphyria cutanea tarda with bone marrow rather than hepatic expression of the disease. Liquid-chromatographic and thin-layer chromatographic analyses of the patients's urine and skin showed predominantly heptacarboxylic porphyrin and uroporphyrin, whereas his stool and bile contained isocoproporphyrin and coproporphyrin as the major products. The data reflect defective uroporphyrinogen decarboxylation. Both analytical methods gave quantitatively similar results for urinary and fecal porphyrins. A triple-lumen perfusion study of samples procured both at the ampulla of Vater and 15 cm downstream provided data for porphyrins excreted in the bile and their reabsorption in the small intestine. We evaluated: suppression by hypertransfusion of bone marrow overproduction of porphyrins and reduction of enteral absorption of porphyrins by orally administered charcoal (Acta Char) and cholestyramine.
17
Krivosheev, Alexander B., L. Ya Kupriyanova e M. A. Kondratova. "DOUBLE PORPHYRIA: LITERATURE REVIEW AND ANALYSIS OF CLINICAL OBSERVATION". Russian Journal of Skin and Venereal Diseases 21, n. 2 (15 aprile 2018): 120–24. http://dx.doi.org/10.18821/1560-9588-2018-21-2-120-124.
Testo completoAbstract (sommario):
A brief review of the literature on the problem of double porphyria and analysis of its own observation is presented. For more than 10 years patient B was observed for more than 10 years with a verified diagnosis of acute intermittent porphyria, which manifested with acute pain abdominal syndrome, neurological disorders in the form of peripheral polyneuropathy and hemiparesis of lower extremities, and hypertension syndrome was also noted. The observed clinical symptoms corresponded to an acute porphyrin crisis in the manifestation and / or relapse of acute intermittent porphyria. The diagnosis was confirmed by a quantitative determination of the excretory profile of porphyrin precursors (δ-aminocaproic acid, porphobilinogen) and porphyrin fractions (uroporphyrin, coproporphyrin). Their concentrations are significantly (especially porphyrin precursors) exceeding the control values, which is the cardinal diagnostic criterion of acute intermittent porphyria. Against the backdrop of persistent clinical and biochemical remission of acute intermittent porphyria, symptoms of photosensitization of the skin (blisters, erosion, pigment spots) on the dorsal surface of the hands began to appear in 4 years. Later, hypertrichosis was formed in the temporo-periorbital region. The constellation type of the excretory profile of porphyrins began to change. Against the backdrop of persistent increased excretion of porphyrin precursors (δ-aminolevulinic acid and porphobilinogen), a progressive increase in the excretion of the fraction of uroporphyrin was observed, which became dominant (up to 58% of the total content of porphyrins). Such a prolonged observation in the dynamics allowed us to state the appearance of a new variant of the porphyrin exchange disturbance, which, taking into account clinical symptoms, corresponded to another form of hepatic porphyria, namely, late cutaneous porphyria. The clinical and biochemical changes in the excretory profile of the parameters of porphyrin metabolism registered in the dynamics of observation may indicate the occurrence of a combined enzymatic defect characteristic of double porphyria. In our case, a manifestation of late cutaneous porphyria was noted against a background of compensated acute intermittent porphyria.
18
Inokuma, Yasuhide, e Atsuhiro Osuka. "meso-Porphyrinyl-Substituted Porphyrin and Expanded Porphyrins". Organic Letters 6, n. 21 (ottobre 2004): 3663–66. http://dx.doi.org/10.1021/ol048953f.
Testo completo
19
Dogra, Ashu. "Role of therapeutic phlebotomy in management of case of porphyria cutanea tarda (PCT) admitted in tertiary care hospital Vadodara". Hematology & Transfusion International Journal 8, n. 1 (30 gennaio 2020): 4–6. http://dx.doi.org/10.15406/htij.2020.08.00212.
Testo completoAbstract (sommario):
Porphyria cutanea tarda is the most frequent type of Porphyria worldwide & presents with skin symptoms mainly. Porphyrias can affect peripheral, autonomic and central nervous system. In Porphyria conditions there is accumulation of heme precursors 5 Aminolevulinic acid, Porphobilinogen and porphyrins which are associated with characteristic clinical feature with acute neurovisceral attacks and skin lesions. This case report summarizes Case of PCT that was successfully managed with Therapeutic Phlebotomy.
20
Beukeveld, G. J., B. G. Wolthers, J. J. van Saene, T. H. de Haan, L. W. de Ruyter-Buitenhuis e R. H. van Saene. "Patterns of porphyrin excretion in feces as determined by liquid chromatography; reference values and the effect of flora suppression." Clinical Chemistry 33, n. 12 (1 dicembre 1987): 2164–70. http://dx.doi.org/10.1093/clinchem/33.12.2164.
Testo completoAbstract (sommario):
Abstract While determining reference values for porphyrins in feces as measured by liquid chromatography, we observed strong fluctuations in fecal porphyrin contents. To explain these fluctuations, we selectively suppressed the intestinal flora of healthy persons. Suppression of aerobic flora had no effect on fecal porphyrin excretions, whereas suppression of anaerobic flora completely inhibited the transformation of protoporphyrin to pempto- and deuteroporphyrin for as long as five days after stopping medication. During this latter, the conversion to mesoporphyrin was clearly increased in one person and in others partly affected or decreased. During complete suppression of flora for prolonged periods, the production of proto- and coproporphyrins was decreased and deutero-, pempto-, and mesoporphyrins were absent. We conclude that the nature of fecal porphyrins is mostly affected by action of anaerobic bacteria, different kinds of bacteria having different effects. Some, like aerobic Gram-negative bacteria, have little or no effect on porphyrins; some cause production of mesoporphyrin; some promote a conversion to pempto- and deuteroporphyrin; and some mainly cause production of copro- and protoporphyrin. We give examples in which normal to slightly increased excretions of fecal porphyrin do not exclude a diagnosis of porphyria, and relatively high concentrations do not confirm one.
21
Uemori, Yoshio, Masato Sakurai, Atsuko Osada, Hiroki Munakata, Hiroyasu Imai e Shigeo Nakagawa. "Synthesis and properties of water-soluble porphyrins bearing multidentate ligands". Journal of Porphyrins and Phthalocyanines 08, n. 08 (agosto 2004): 1047–54. http://dx.doi.org/10.1142/s1088424604000416.
Testo completoAbstract (sommario):
Water-soluble porphyrins bearing multidentate ligands were prepared by covalent binding of nitrilotriacetic acid to 5,10,15,20-tetrakis(4-aminophenyl)porphyrin or three atropisomers of 5,10,15,20-tetrakis(2-aminophenyl)porphyrin. The acid-base properties and monomer-dimer behavior of the porphyrins were affected by the positions of the multidentate ligands with respect to the porphyrin plane. Among the porphyrins, the porphyrin bearing multidentate ligands at the para position of the phenyl groups dimerized in an aqueous solution. The association constants of the porphyrins with various aromatic compounds were studied in water at pH 7.4 containing 10 mM HEPES at 25°C. These values varied with the structure and charges of both the porphyrins and the aromatic compounds. The association constants of the porphyrin bearing multidentate ligands at the 2-position of the phenyl groups were small compared to those of the porphyrin bearing multidentate ligands at the 4-position.
22
Johnson, P. M., S. L. Perkins e S. W. Kennedy. "A high-speed liquid-chromatographic method for measuring urinary porphyrins." Clinical Chemistry 34, n. 1 (1 gennaio 1988): 103–5. http://dx.doi.org/10.1093/clinchem/34.1.103.
Testo completoAbstract (sommario):
Abstract We describe a rapid quantitative and qualitative "high-performance" liquid-chromatographic (HPLC) method for measuring porphyrins in urine. Direct injection of acidified, filtered urine onto a 3-micron (particle size) 3-cm-long reversed-phase column fully resolves uroporphyrin, hepta-, hexa-, and pentacarboxylic acid porphyrins, and coproporphyrin. Instrument response is linearly related to concentration over the range 25 to 300 nmol/L. The method provides data essential for the differential diagnosis of porphyric states, including porphyria variegata and porphyria cutanea tarda. This relatively inexpensive method requires a run time of only 8 min per sample, making it particularly suitable for routine use in the clinical chemistry laboratory.
23
Egemen, Gamze, Mustafa Hayvalı, Zeynel Kılıç, A. Osman Solak e Zafer Üstündağ. "Phosphorus-nitrogen compounds Part 17: The synthesis, spectral and electrochemical investigations of porphyrino-phosphazenes". Journal of Porphyrins and Phthalocyanines 14, n. 03 (marzo 2010): 227–34. http://dx.doi.org/10.1142/s1088424610001945.
Testo completoAbstract (sommario):
The reactions of unsymmetrical porphyrins (1 and 2) with Ni(OAc)2·4H2O in boiling DMF produce porphyrin complexes (3 and 4). From the reactions of free porphyrin ligands 1 and 2 with hexachlorocyclotriphosphazatriene, N3P3Cl6 , the new free porphyrino-phosphazene derivatives (5 and 6) are obtained. On the other hand, the reactions of N3P3Cl6 with porphyrin complexes (3 and 4) afford the new porphyrino-phosphazene complexes (7 and 8). In the literature there are a few examples of the porphyrino-phosphazene architectures. The structural investigations of all the compounds have been made by elemental analyses, MS, FTIR, 1H NMR, 31P NMR and UV-visible techniques. The cyclic voltammograms (CVs) are examined in acetonitrile (MeCN) containing 0.1 M tetrabutylammonium-tetrafluoroborate (TBATFB) to investigate the surface attachment properties at the glassy carbon electrode (GCE) and the influence of the presence of metal cations in the porphyrin ring.
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Chambron, Jean-Claude, Jean-Paul Collin, Isabelle Dixon, Valérie Heitz, Xavier J. Salom-Roig e Jean-Pierre Sauvage. "Synthesis of one-dimensional bis-porphyrinic compounds with a transition metal complex as bridging unit". Journal of Porphyrins and Phthalocyanines 08, n. 01 (gennaio 2004): 82–92. http://dx.doi.org/10.1142/s1088424604000076.
Testo completoAbstract (sommario):
Linear multicomponent systems, consisting of two porphyrins attached to a central transition metal center, have been prepared and some of their electron- or energy transfer properties have been studied. Each porphyrin is covalently bound to a bidentate or a terdentate ligand, these coordinating molecules being gathered around the metal to afford the desired structure. The spatial arrangement is such that the porphyrinic components are located at both ends of an axis, the transition metal occupying its center. The edge-to-edge distance between the porphyrins is relatively large (~ 20 to 25 Å) and, due to the rigidity of the connectors, it is very well controlled. Three different strategies have been used to construct such assemblies. In the first approach, the porphyrinic fragments are attached at the back of 2,2′,6′,2″-terpyridine ligands (terpy), on the central position (4′). After reaction with an appropriate metal center (ruthenium(II) or iridium(III)), an octahedral complex is obtained which constitutes the central part of the assembly, whereas the porphyrins are at the periphery of the central complex. The second strategy involves the preparation of a 5,5′-disubstituted 2,2′-bipyridine (bipy) ligand followed by its coordination to ruthenium(II). Subsequently, the porphyrinic nuclei are constructed at both ends of the substituents, leading to a linear geometry with a central complex and two laterally-disposed porphyrins. Finally, a very special ligand has been designed and synthesized, which incorporates two 1,10-phenanthroline nuclei (phen). This ligand can wrap itself around an octahedral center (ruthenium(II)) so as to generate a helical arrangement. Both ends of the single-stranded helix can subsequently be attached to porphyrins.
25
Dinache, Andra, Simona Nistorescu, Tatiana Tozar, Adriana Smarandache, Mihai Boni, Petronela Prepelita e Angela Staicu. "Spectroscopic Investigations of Porphyrin-TiO2 Nanoparticles Complexes". Molecules 28, n. 1 (30 dicembre 2022): 318. http://dx.doi.org/10.3390/molecules28010318.
Testo completoAbstract (sommario):
This study presents the spectral characterization of TiO2 nanoparticles (NPs) functionalized with three porphyrin derivatives: 5,10,15,20-(Tetra-4-aminophenyl) porphyrin (TAPP), 5,10,15,20-(Tetra-4-methoxyphenyl) porphyrin (TMPP), and 5,10,15,20-(Tetra-4-carboxyphenyl) porphyrin (TCPP). UV-Vis absorption and Fourier transform infrared spectroscopy–attenuated total reflection (FTIR-ATR) spectroscopic studies of these porphyrins and their complexes with TiO2 NPs were performed. In addition, the efficiency of singlet oxygen generation, the key species in photodynamic therapy, was investigated. UV-Vis absorption spectra of the NPs complexes showed the characteristic bands of porphyrins. These allowed us to determine the loaded porphyrins on TiO2 NPs functionalized with porphyrins. FTIR-ATR revealed the formation of porphyrin-TiO2 complexes, suggesting that porphyrin adsorption on TiO2 may involve the pyrroles in the porphyrin ring, or the radicals of the porphyrin derivative. The quantum yield for singlet oxygen generation by the studied porphyrin complexes with TiO2 was higher compared to bare porphyrins for TAPP and TMPP, while for the TCPP-TiO2 NPs complex, a decrease was observed, but still maintained a good efficiency. The TiO2 NPs conjugates can be promising candidates to be tested in photodynamic therapy in vitro assays.
26
Baytaeva, D. A., e S. S. Bessmel’tsev. "Porphyrin metabolism in secondary hepatic porphyria in patients with hereditary deficiency of glucose-6-phosphate dehydrogenase". Kazan medical journal 93, n. 3 (15 giugno 2012): 451–55. http://dx.doi.org/10.17816/kmj1865.
Testo completoAbstract (sommario):
Aim. The study the porphyrin metabolism during the development of secondary hepatic porphyria in patients with glucose-6-phosphate dehydrogenase deficiency. Methods. Examined were 148 male patients aged 5-19 years (median 12 years) with impaired activity of glucose-6-phosphate dehydrogenase in combination with β-thalassemia and without it. Qualitative and quantitative methods of examining the activity of this enzyme were used in order to verify the diagnosis. Taking into account the varying degree of glucose-6-phosphate dehydrogenase deficiency, the indices of metabolism of the enzyme and of the porphyrins were correlated with the severity of anemia, functional liver capacities, with parameters reflecting iron content in blood serum, bone marrow, liver and urine. The markers of intoxication were also taken into account in the development of secondary hepatic porphyria and endotoxemia. Therapeutic plasmapheresis was used to correct the revealed disorders. Results. The influence of glucose-6-phosphate dehydrogenase deficiency on the metabolism of porphyrins and liver functional status has been shown, which leads to the development of anemia and endogenous intoxication. With the help of parameters, which characterize the porphyrin metabolism in patients, secondary hepatic porphyria was revealed. It was established that determination of the content of glucose-6-phosphate dehydrogenase and porphyrins makes it possible to detect disturbances in heme synthesis at an early stage and to evaluate the compensatory abilities of the liver. An important diagnostic feature for glucose-6-phosphate dehydrogenase deficiency, regardless of severity, is the impaired synthesis of the end products of metabolism of porphyrins - uro-, copro- and protoporphyrin. The effectiveness of therapeutic plasmapheresis for hemolysis, secondary hepatic porphyria and endogenous intoxication has been shown. Conclusion. Increased excretion of uro-and coproporphyrin with urine reflects the severity of endotoxemia, and is an alternative to markers of intoxication; high concentration of free protoporphyrin and low concentration of uro- and coproporphyrin in erythrocytes is an important diagnostic sign of impaired activity of glucose-6-phosphate dehydrogenase in patients.
27
Erwin, Angelika L., e Manisha Balwani. "Porphyrias in the Age of Targeted Therapies". Diagnostics 11, n. 10 (29 settembre 2021): 1795. http://dx.doi.org/10.3390/diagnostics11101795.
Testo completoAbstract (sommario):
The porphyrias are a group of eight rare genetic disorders, each caused by the deficiency of one of the enzymes in the heme biosynthetic pathway, resulting in the excess accumulation of heme precursors and porphyrins. Depending on the tissue site as well as the chemical characteristics of the accumulating substances, the clinical features of different porphyrias vary substantially. Heme precursors are neurotoxic, and their accumulation results in acute hepatic porphyria, while porphyrins are photoactive, and excess amounts cause cutaneous porphyrias, which present with photosensitivity. These disorders are clinically heterogeneous but can result in severe clinical manifestations, long-term complications and a significantly diminished quality of life. Medical management consists mostly of the avoidance of triggering factors and symptomatic treatment. With an improved understanding of the underlying pathophysiology and disease mechanisms, new treatment approaches have become available, which address the underlying defects at a molecular or cellular level, and promise significant improvement, symptom prevention and more effective treatment of acute and chronic disease manifestations.
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CHATTERJEE, SHAMPA, e T. S. SRIVASTAVA. "Spectral investigations of the interaction of some porphyrins with bovine serum albumin". Journal of Porphyrins and Phthalocyanines 04, n. 02 (marzo 2000): 147–57. http://dx.doi.org/10.1002/(sici)1099-1409(200003)4:2<147::aid-jpp163>3.0.co;2-z.
Testo completoAbstract (sommario):
The binding of meso-tetrakis[4-(carboxymethyleneoxy)phenyl]porphyrin (T4CPP), meso-tetrakis[3-(carboxymethyleneoxy)phenyl]porphyrin (T3CPP) and meso-tetrakis[3,4-bis(carboxymethyl-eneoxy)phenyl]porphyrin (T3, 4BCPP) with bovine serum albumin (BSA) at pH 7.4 has been studied at 420 nm in detail. The results show hypochromicity along with a red shift in the Soret band of the porphyrins. This suggests that these porphyrins bind to BSA as monomers. Further analysis of these data supports the non-interactive binding of T4CPP and T3CPP with BSA and the cooperative binding of T3, 4BCPP with BSA. These binding data have been interpreted in terms of one specific binding site and several non-specific binding sites on BSA for the porphyrins. The absorption spectral changes of the porphyrins between 400 and 450 nm when titrated with BSA suggest that there is another specific binding site on BSA for the porphyrins. These two specific binding sites have also been supported by circular dichroism (CD) studies. The absorption spectral and CD studies on the interactions of the porphyrins with BSA further suggest that these interactions are dependent on the number and configuration of substituents in the phenyl groups of the porphyrins. The contact energy transfer from the aromatic amino acid residues tryptophan and tyrosine of BSA to the porphyrins in the BSA–porphyrin complexes has also been studied using fluorescence spectroscopy. These energy transfer data show the energy transfer from tryptophan to the porphyrins for their binding to site I of BSA and from tyrosine to the porphyrins for their binding to site II of BSA. Unfolding studies of the BSA–porphyrin systems indicate that the tertiary structure is essential for the binding of the porphyrins. A correlation between the accumulation of99 mTc -labelled T4CPP and T3, 4BCPP in tumour tissue and their binding at site II of BSA is possible. The interaction of the porphyrins can also be used as a model for mitochondrial interactions.
29
Yan, Guo-Ping, Kathryn E. Fairfull-Smith, Craig D. Smith, Graeme R. Hanson e Steven E. Bottle. "Porphyrin containing isoindoline nitroxides as potential fluorescence sensors of free radicals". Journal of Porphyrins and Phthalocyanines 15, n. 04 (aprile 2011): 230–39. http://dx.doi.org/10.1142/s1088424611003203.
Testo completoAbstract (sommario):
A series of new spin-labeled porphyrin containing isoindoline nitroxide moieties were synthesized and characterized as potential free radical fluorescence sensors. Fluorescence-suppression was observed in the free-base monoradical porphyrins, whilst the free-base biradical porphyrins exhibited highly suppressed fluorescence about three times greater than the monoradical porphyrins. The observed fluorescence-suppression was attributed to enhanced intersystem crossing resulting from electronexchange between the doublet nitroxide and the excited porphyrin fluorophore. Notably, fluorescencesuppression was not as strong in the related metalated porphyrins, possibly due to insufficient spin coupling between the nitroxide and the porphyrin. Continuous wave EPR spectroscopy of the diradical porphyrins in fluid solution suggests that the nitroxyl-nitroxyl interspin distance is long enough and tumbling is fast enough not to detect dipolar coupling.
30
Ricci, Andrea, Claudio Carmine Guida, Paola Manzini, Chiara Cuoghi e Paolo Ventura. "Kidney Involvement in Acute Hepatic Porphyrias: Pathophysiology and Diagnostic Implications". Diagnostics 11, n. 12 (10 dicembre 2021): 2324. http://dx.doi.org/10.3390/diagnostics11122324.
Testo completoAbstract (sommario):
Porphyrias are a group of rare disorders originating from an enzyme dysfunction in the pathway of heme biosynthesis. Depending on the specific enzyme involved, porphyrias manifest under drastically different clinical pictures. The most dramatic presentation of the four congenital acute hepatic porphyrias (AHPs: acute intermittent porphyria—AIP, ALAD deficiency, hereditary coproporphyria—HCP, and porphyria variegata—VP) consists of potentially life-threatening neurovisceral attacks, for which givosiran, a novel and effective siRNA-based therapeutic, has recently been licensed. Nonetheless, the clinical manifestations of acute porphyrias are multifaceted and do not limit themselves to acute attacks. In particular, porphyria-associated kidney disease (PAKD) is a distinct, long-term degenerating condition with specific pathological and clinical features, for which a satisfactory treatment is not available yet. In PAKD, chronic tubule-interstitial damage has been most commonly reported, though other pathologic features (e.g., chronic fibrous intimal hyperplasia) are consistent findings. Given the relevant role of the kidney in porphyrin metabolism, the mechanisms possibly intervening in causing renal damage in AHPs are different: among others, δ-aminolevulinic acid (ALA)-induced oxidative damage on mitochondria, intracellular toxic aggregation of porphyrins in proximal tubular cells, and derangements in the delicate microcirculatory balances of the kidney might be implicated. The presence of a variant of the human peptide transporter 2 (PEPT2), with a greater affinity to its substrates (including ALA), might confer a greater susceptibility to kidney damage in patients with AHPs. Furthermore, a possible effect of givosiran in worsening kidney function has been observed. In sum, the diagnostic workup of AHPs should always include a baseline evaluation of renal function, and periodic monitoring of the progression of kidney disease in patients with AHPs is strongly recommended. This review outlines the role of the kidney in porphyrin metabolism, the available evidence in support of the current etiologic and pathogenetic hypotheses, and the known clinical features of renal involvement in acute hepatic porphyrias.
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Phillips, John D., Hector A. Bergonia e James P. Kushner. "Cellular Distribution of Porphyrins In Porphyria Cutanea Tarda". Blood 116, n. 21 (19 novembre 2010): 165. http://dx.doi.org/10.1182/blood.v116.21.165.165.
Testo completoAbstract (sommario):
Abstract Abstract 165 Porphyria cutanea tarda (PCT), the most common porphyria in humans, results from subnormal activity of uroporphyrinogen decarboxylase (URO-D) in hepatocytes. The enzymatic defects results in cellular accumulation of the highly carboxylated uroporphyrinogen and heptacarboxyl porphyrinogen. The excess porphyrinogens are oxidized to porphyrins, exported to plasma and eventually eliminated in the urine. The mechanism by which uroporphyrin and heptacarboxyl porphyrin are transported across cellular membranes is not known. We generated a mouse model of the familial form of PCT 1. Mice heterozygous for a deletion of the Uro-d gene and homozygous for deletion of the hemochromatosis gene Hfe (genotype Uro-d+/−;Hfe−/−) accumulate hepatic porphyrins in a pattern similar to humans with PCT. Hepatocytes were isolated from porphyric mice using an in situ two-step EGTA/collagenase perfusion followed by an iso-density Percoll centrifugation step to remove damaged cells. Confocal microscopy was used to examine cells for porphyrin fluorescence by illuminating cells at 405 nm and monitoring the emission between 600 and 650 nm. Fluorescent porphyrins were present as punctate bodies within the cytosol of the hepatocytes. Co-staining with fluorescent probes (mitotracker and lysotracker) demonstrated co-localization of porphyrins with lysotracker, indicating that porphyrins were present in lysosomes. We utilized a yeast model to determine the molecular mechanism by which porphyrins are transferred from the cytosol to the lysosome. In S. cerevisiae the vacuole is analogous to the mammalian lysosome. The yeast homolog of Uro-d is HEM12. In a hem12 deletion strain, uroporphyrin accumulates in the vacuole. ABC transporters have previously been shown to transport tetrapyrroles across membranes. We used a candidate approach to identify the ABC transporter responsible for vacuolar transport of uroporphyrin by creating deletion strains of the five known vacuolar ABC transporters BPT1, YBT1, YCF1, VMR1 and NFT1. Vacuolar membranes were prepared from these strains by spheroplasting yeast with oxalyticase, osmotically lysing the cells and floating the vacuoles on a Ficoll gradient. Isolated vacuoles were assayed for tetrapyrrole uptake by incubating vacuoles (200 ug total protein), substrate (20 uM) and Mg2+-ATP (50 uM) at 30 °C for 1, 2, 4 and 8 min in 100 uL of import buffer (300 mM sorbitol, pH 6.8). As controls, reactions were carried out at 4 °C and in the absence of ATP. Vacuolar import of uroporphyrin was temperature-dependent (no import occurred at 4 °C) and was dependent on the presence of ATP. Uroporphyrinogen was imported but, the rate was approximately 10% that of uroporphyrin. No import of protoporphyrin IX was observed. Import of uroporphyrin into vacuoles from each of the ABC transporter mutants was essentially the same as wild-type vacuoles with the exception of the ycf1 deletion strain. There was no import of uroporphyrin or uroporphyrinogen in vacuoles from the ycf1 deletion stain. The mammalian ABC-type transporter with the highest homology to yeast YCF1 is ABCC1. ABCC1 has recently been shown to transport a tetrapyrrole (cobalamin) 2 making ABCC1 a candidate transporter responsible for moving uroporphyrin across cellular membranes in humans. 1. Phillips JD, Jackson LK, Bunting M, et al. A mouse model of familial porphyria cutanea tarda. Proc Natl Acad Sci U S A. 2001;98:259-264. 2. Beedholm-Ebsen R, van de Wetering K, Hardlei T, Nexo E, Borst P, Moestrup SK. Identification of multidrug resistance protein 1 (MRP1/ABCC1) as a molecular gate for cellular export of cobalamin. Blood. 2010;115:1632-1639. Disclosures: No relevant conflicts of interest to declare.
32
Matsumoto, Jin, Tsutomu Shiragami, Kazutaka Hirakawa e Masahide Yasuda. "Water-Solubilization of P(V) and Sb(V) Porphyrins and Their Photobiological Application". International Journal of Photoenergy 2015 (2015): 1–12. http://dx.doi.org/10.1155/2015/148964.
Testo completoAbstract (sommario):
Porphyrins have been widely utilized as biochemical and biological functional chromophores which can operate under visible-light irradiation. Water-soluble porphyrins have been used as the drug for photodynamic therapy (PDT) and photodynamic inactivation (PDI). Although usual water-solubilization of porphyrins has been achieved by an introduction of an ionic group such as ammonium, pyridinium, sulfonate, phosphonium, or carboxyl to porphyrin ring, we proposed the preparation of water-soluble P and Sb porphyrins by modification of axial ligands. Alkyl (type A), ethylenedioxy (type E), pyridinium (type P), and glucosyl groups (type G) were introduced to axial ligands of Sb and P porphyrins to achieve water-solubilization of Sb porphyrin and P porphyrins. Here, we review their water-soluble P and Sb porphyrins from the standpoints of preparation, bioaffinity, and photosensitized inactivation.
33
Sassa, Shigeru. "Novel Effects of Heme Biological Systemst and Heme-related Compounds in Biological Systems". Current Medicinal Chemistry 3, n. 4 (agosto 1996): 273–90. http://dx.doi.org/10.2174/092986730304220302112129.
Testo completoAbstract (sommario):
Abstract: Heme and heme-related compounds such as porphyrins have a variety of biological and clinical activities. This review highlights some of the novel effects of these compounds in medicinal chemistry. Heme which has no photoreactive properties, can serve as the prosthetic group for various hemoproteins, or as a substrate for microsomal heme oxygenase (HO). In contrast, porphyrins have photodynamic activities but usually do not serve as substrates in biological systems. Thus, heme and heme analogues are often used to influence enzyme activities in tissues, while porphyrins by taking advantage of their photoreactive properties are used as drugs in medicine. There are four major applications of these compounds, namely the use of (i) heme in the treatment of porphyrias and hematological disorders, (ii) synthetic metalloporphyrins in the treatment of hyperbilirubinemia, (iii) metal-free porphyrins in photodynamic therapy of malignant tumors, and (iv) porphyrin derivatives as contrast reagents in radiography. Solubility, stability, pharmacokinetics, pharmacodynamics and analytical techniques are all important considerations in the medicinal chemistry of these compounds. In man and animals in vivo, the rate of synthesis and catabolism of heme, as well as disorders of heme synthesis are important in understanding pathophysiological effects of these compounds.
34
Sánchez-Muñoz, Esteban, José L. Gárate-Morales, Jacinto Sandoval-Lira, Julio M. Hernández-Pérez e Rocío Aguilar-Sánchez. "Porphyrin Supramolecular Arrays Formed by Weakly Interacting Meso-Functional Groups on Au(111)". Molecules 24, n. 18 (12 settembre 2019): 3326. http://dx.doi.org/10.3390/molecules24183326.
Testo completoAbstract (sommario):
The formation of a binary porphyrinic self-assembled system between meso-tetrakis(4-carboxyphenyl) porphyrin (TCPP) and meso-tetrakis(4-dimethyl amino) porphyrin (TDAP) was easily designed through non-covalent interactions in solution and adsorbed on a gold substrate. It was found that non-covalent interactions and geometrical conformations between porphyrins allow their self-assembly into a well-defined arrangement, which was confirmed by UV-Vis spectroscopy, electrochemistry, atomic force microscopy and density functional theory (DFT) studies.
35
VINODU, MIKKI V., e M. PADMANABHAN. "Ionically bound metalloporphyrin pairs on solid polymer support". Journal of Porphyrins and Phthalocyanines 05, n. 11 (novembre 2001): 763–66. http://dx.doi.org/10.1002/jpp.543.
Testo completoAbstract (sommario):
The present work demonstrates a simple and elegant strategy by which synthetically simple porphyrins are grafted on solid polymer support to generate porphyrin pairs held together by strong coulombic forces. Metalloporphyrins of tetra(4-pyridyl)porphyrins (MTPyP) were reacted with chloromethylated polystyrene (PS) beads to get covalently bound monocationic porphyrins on the polymer support (PS–MTPyP+). These were then converted to their tetracationic species (PS–MTMe3PyP4+) by exhaustive quaternisation, using CH 3 I . These polymer-grafted cationic porphyrins were made to react with tetraanionic p-sulphonated phenylporphyrins (MTPPS4-) in aqueous conditions. Analysis showed that the PS–MTMe3PyP4+ take up MTPPS4- in exactly 1:1 stoichiometry to form strongly bound (ionically) porphyrin pairs. A variety of homo- and hetero-porphyrin pairs involving central metal ions like Mn , Co , Cu , Zn and Ag and also free-base porphyrins are generated by this strategy.
36
YUAN, HONGPING, e L. KEITH WOO. "Synthesis and Characterization of Thiol-Derivatized Porphyrins and Metalloporphyrin complexes". Journal of Porphyrins and Phthalocyanines 01, n. 02 (aprile 1997): 189–200. http://dx.doi.org/10.1002/(sici)1099-1409(199704)1:2<189::aid-jpp23>3.0.co;2-g.
Testo completoAbstract (sommario):
A series of thiol-derivatized porphyrins and the corresponding cobalt and zinc complexes were synthesized from 5-(p-aminophenyl)-10,15,20-triphenylporphyrin ( H 2 TPP - NH 2), and 5α,15α-bis(o-aminophenyl)porphyrin ( H 2 DPE - ( NH 2)2). These derivatized porphyrins have a different number of thiol appendages attached via amide linkages at different locations. The thiol-derivatized porphyrins made from H 2 TPP - NH 2, H 2 TPP - NHC ( O )( CH 2) n SH ( n = 2, 4, 5, 10), have one alkyl-thiol appendage attached to the porphyrin through an amide linkage on the p-aminophenyl position. The derivatives made from H 2 DPE -( NH 2)2 have two alkyl-thiol appendages attached to the porphyrin through amide linkages on the o-aminophenyl positions on the same face of the porphyrin ring. These thiol-derivatized porphyrins are important adsorbates for the preparation of thiol–porphyrin monolayers on gold.
37
Bakali, E. El, H. Kerrouch, R. El Chafi, T. Hanafi, Y. Zemmez, R. Frikh e N. Hjira. "PORPHYRIA CUTANEATARDA: A CASE REPORT". International Journal of Advanced Research 11, n. 03 (31 marzo 2023): 997–1000. http://dx.doi.org/10.21474/ijar01/16524.
Testo completoAbstract (sommario):
Porphyria cutaneatarda (PCT) is a rare disease of porphyrin metabolism, related to a deficiency of Uroporphyrinogen decarboxylase activity. Clinically, it manifests itself by a skin fragility in photo-exposed areas. The characteristic biochemical profile of PCT, with elevated levels of urinary and plasma porphyrins, establishes the diagnosis. Treatment is based on phlebotomy, hydroxychloroquine (100 to 200 mg twice weekly) and control of susceptibility factors. We report a case of porphyria cutaneatarda in a male coast guard by profession.
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Imahori, Hiroshi, e Tomokazu Umeyama. "Porphyrin-modified electrodes for solar energy conversion". Journal of Porphyrins and Phthalocyanines 13, n. 10 (ottobre 2009): 1063–68. http://dx.doi.org/10.1142/s1088424609001315.
Testo completoAbstract (sommario):
This mini review presents our recent developments in porphyrin-modified electrodes for solar energy conversion. Various porphyrins have been assembled on nanostructured semiconducting electrodes to achieve efficient photocurrent generation. First, porphyrins have been organized with fullerenes onto semiconducting electrodes to elucidate the relationship between the molecular structures, film structures, and photoelectrochemical properties of the modified electrodes. Formation of hole and electron-transporting highways in the porphyrin/fullerene composite film led to the remarkable enhancement of photocurrent generation. Second, porphyrin-modified single-walled carbon nanotubes have also been assembled onto semiconducting electrodes. The degree of chemical functionalization by the bulky porphyrins was found to have a large impact on the photoelectrochemical properties. Third, asymmetrically π-elongated porphyrins have been successfully employed in dye-sensitized solar cells to improve the cell performance as well as the light-harvesting properties. The power conversion efficiency of the fused porphyrin cell was improved by 50% compared to the reference cell using the corresponding unfused porphyrin. Finally, carboxyquinoxalino derivatives of zinc porphyrin have been further developed to extend the concept of asymmetrically π-elongated porphyrins. The maximum power conversion efficiency of 5.2% was obtained by using 5,10,15,20-tetrakis(2,4,6-trimethylphenyl)-6′-carboxyquinoxalino[2,3-b]porphyrinatozinc(II).
39
Abe, K., e R. Konaka. "Quantification of urinary porphyrins by liquid chromatography after oxidation of porphyrinogens." Clinical Chemistry 35, n. 8 (1 agosto 1989): 1619–22. http://dx.doi.org/10.1093/clinchem/35.8.1619.
Testo completoAbstract (sommario):
Abstract A quantitative "high-performance" liquid-chromatographic method is described for determining porphyrins in human urine. Porphyrinogens in urine are first converted to the corresponding porphyrins by oxidation with iodine. Uroporphyrin, hepatacarboxylic acid porphyrin, hexacarboxylic acid porphyrin, pentacarboxylic acid porphyrin, and coproporphyrin I and III isomers are then separated on a reversed-phase column and measured by fluorometry. Analysis for the six porphyrins is complete within 24 min, including reconditioning for the next sample. The detection limit (twice the signal/noise ratio) for each porphyrin was 1 nmol/L for urine (25 fmol per 50-microL injection). Mean analytical recovery of each porphyrin ranged from 85% to 91%, within-day CVs from 1.4% to 7.3%. Normal reference intervals for porphyrins were established by assaying urine samples from 75 healthy subjects. Significant sex-related differences in coproporphyrin I and III isomers were evident when the values were expressed as nanomoles per gram of creatinine. Coproporphyrin isomer ratio was estimated for utility in the diagnosis of porphyrinurias.
40
Almeida, José, Maria E. Fortună, Lucia Pricop, Andrei Lobiuc, Andreia Leite, André M. N. Silva, Rodrigo P. Monteiro, Maria Rangel, Valeria Harabagiu e Ana M. G. Silva. "(Aminophenyl)porphyrins as precursors for the synthesis of porphyrin-modified siloxanes". Journal of Porphyrins and Phthalocyanines 23, n. 09 (settembre 2019): 1001–12. http://dx.doi.org/10.1142/s1088424619500573.
Testo completoAbstract (sommario):
The present research reports the efficient synthesis of mono- and di-(aminophenyl)porphyrins and their metalation with Zn(II) using microwave irradiation. The subsequent reaction of amino-functionalized porphyrins with siloxane moieties bearing epoxy or carboxyl functional groups provided four new porphyrin-modified siloxanes. The structure of the resulting derivatives was established by 1H-NMR and MALDI-TOF-MS. The optical properties of the porphyrin chromophores were preserved, as proven by comparing the absorption and emission spectra of the initial porphyrins to those of the porphyrin-modified siloxanes.
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Young, James W., e Eugene T. Conte. "Porphyrias and Porphyrins". International Journal of Dermatology 30, n. 6 (giugno 1991): 399–406. http://dx.doi.org/10.1111/j.1365-4362.1991.tb03893.x.
Testo completo
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Shee, Nirmal Kumar, Min Kyoung Kim e Hee-Joon Kim. "Supramolecular Porphyrin Nanostructures Based on Coordination-Driven Self-Assembly and Their Visible Light Catalytic Degradation of Methylene Blue Dye". Nanomaterials 10, n. 11 (22 novembre 2020): 2314. http://dx.doi.org/10.3390/nano10112314.
Testo completoAbstract (sommario):
A series of porphyrin triads (1–4), in which each triad is composed of a Sn(IV) porphyrin and two free-base (or Zn(II)) porphyrins, was synthesized and their self-assembled nanostructures were studied. Depending on the substituent on porphyrin moieties, each triad was self-assembled into a different nanostructure. In particular, the cooperative coordination of 3-pyridyl groups in the Sn(IV) porphyrin with the axial Zn(II) porphyrins in triad 4 leads to forming uniform nanofibers with an average width of 10–22 nm. Other triads without the coordinating interaction between the central Sn(IV) porphyrin and the axial porphyrins formed irregularly shaped aggregates in contrast. The morphologies of nanofiber changed drastically upon the addition of pyrrolidine, in which pyrrolidine molecules break down the self-assembly process by coordinating with the axial Zn(II) porphyrins. All porphyrin aggregates exhibited efficient photocatalytic performances on the degradation of methylene blue dye under visible light irradiation. The degradation efficiencies after 2 h were observed to be between 70% and 95% for the aggregates derived from the four triads.
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Buraga, Ioan, e Adrian-Florin Dobrescu. "19-year-old female with abdominal pain". Romanian Journal of Neurology 12, n. 1 (31 marzo 2013): 30–36. http://dx.doi.org/10.37897/rjn.2013.1.4.
Testo completoAbstract (sommario):
Porphyria is a group of at least 8 diseases that differ greatly between them. Common feature of these diseases is the accumulation in the body of porphyrins or porphyrin precursors, due to defects of specific enzymes in the biosynthesis of hem. Many symptoms of porphyria are nonspecific and therefore the diagnosis is often delayed. Laboratory tests can confirm or exclude the diagnosis of porphyria. However, certain diagnosis requires demonstration of specific enzyme deficiency. The presented case demonstrates the difficulty in diagnosis of acute intermittent porphyria (AIP) in a young woman without a history of significant pathology.
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Aloyan, Lusine, Yeva Dalyan e Aleksey Gogolev. "New Porphyrins/Calf Thymus DNA Complexes - Their Thermostability". Advanced Materials Research 1084 (gennaio 2015): 554–58. http://dx.doi.org/10.4028/www.scientific.net/amr.1084.554.
Testo completoAbstract (sommario):
The paper studies the melting parameters of the complexes of water soluble cationic 3N- and 4N-pyridyl porphyrins with different peripheral substituents (oxyethyl, buthyl, allyl, metallyl) with DNA. The results indicate that the presence of porphyrin changes the shape and parameters of DNA melting curve. The porphyrin concentration increase results in the increase of the melting temperature (Tm) and melting interval (ΔT) of DNA. With the porphyrin-DNA concentration ratio ν = 0.01, changes of melting temperature have not been observed. The melting intervals almost do not change upon the addition of the 4N- porphyrins, while the decrease of ΔT is observed in the presence of 3N-porphyrins. Because of the intercalation binding mechanism occurring in GC-rich regions of DNA, we assume that 3N-porphyrins intercalated in GC-rich regions, reduce the thermal stability of these sites, bringing them closer to the thermal stability of the AT-sites, which is the reason for the decrease in melting interval. While with the relative concentration ν = 0.01 for 4-N porphyrins the external binding mechanism “turns on” and destabilizing effect of porphyrins on GC-pairs compensated by their stabilizing effect on AT-pairs. As a result, no change in the melting parameters of DNA is observed upon complexation with these porphyrins.
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Ikawa, Yoshiya, Sho Katsumata, Ryuichi Sakashita, Shinobu Sato, Shigeori Takenaka e Hiroyuki Furuta. "Water-soluble porphyrinoids as G-quadruplex binders and telomerase inhibitors". Journal of Porphyrins and Phthalocyanines 20, n. 08n11 (agosto 2016): 1041–48. http://dx.doi.org/10.1142/s108842461650053x.
Testo completoAbstract (sommario):
Water-soluble derivatives of three kinds of expanded porphyrins (N-fused pentaphyrin, hexaphyrin, and heptaphyrin) were synthesized and their binding ability to G-quadruplex (G4-) DNA was evaluated. The inhibitory effects on enzymatic telomere extension were also investigated together with other tetrapyrrolic porphyrinoids. While expanded porphyrins increased the melting temperature of G4-DNA more effectively than the regular porphyrins, a porphyrin isomer (N-confused porphyrin) showed the highest inhibitory effect on telomerase activity.
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Wang, Xia, Yu Cai, Weiqin Li, Yuanyuan Jia, Jiangfeng Fu, Yaping Ni e Kaige Liu. "Research Progress on Serum Porphyrin and Chronic Liver Disease". Journal of Clinical and Nursing Research 6, n. 3 (30 maggio 2022): 221–28. http://dx.doi.org/10.26689/jcnr.v6i3.4017.
Testo completoAbstract (sommario):
Liver cirrhosis is an important cause of chronic liver cancer. At present, a breakthrough has been achieved in the development of chronic hepatitis C treatment, but there is no effective measure to completely cure chronic hepatitis B. Porphyrins are a class of macromolecular heterocyclic compounds formed by interconnecting the ?-carbon atoms of four pyrrole-like substituents through hypomethyl bonds. Porphyrins and their derivatives widely exist in organelles related to energy transfer in organisms. They are mainly involved in the synthesis of heme in human body. Heme is an iron-containing porphyrin compound, 15–20% of which is synthesized and utilized in the liver. Studies have found that porphyrin metabolism disorder can occur in patients with chronic liver disease. The early stage of viral hepatitis is accompanied by increased production of porphyrins and their compounds, increased levels of peripheral circulating porphyrins, porphyrin cholestasis, and biochemical changes of free porphyrins which precede the histological changes. The accumulation of serum and liver protoporphyrins and the oxidative stress can cause liver and extrahepatic damage. On the one hand, porphyrin metabolism disorder can aggravate chronic liver disease, and even progress to liver cirrhosis and liver cancer. On the other hand, chronic liver disease can also aggravate porphyrin metabolism disorder, recurrent attacks, and damage to liver and extrahepatic tissues and organs.
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Sánchez-Resa, Daniel, Laetitia Schoepff, Ryan Djemili, Stéphanie Durot, Valérie Heitz e Barbara Ventura. "Photophysical properties of porphyrinic covalent cages endowed with different flexible linkers". Journal of Porphyrins and Phthalocyanines 23, n. 07n08 (luglio 2019): 841–49. http://dx.doi.org/10.1142/s1088424619500925.
Testo completoAbstract (sommario):
In-depth photophysical studies of four flexible covalent cages bearing either two free-base porphyrins or one free-base porphyrin and one Zn(II) porphyrin, connected by linkers of different lengths, are reported. In the case of the cages with two free-base porphyrins, exciton coupling between the porphyrins is evidenced by large and split Soret bands in the absorption spectra, but the different length of the linkers has only a slight effect on their emission properties. Strong electronic interactions between the porphyrins are also evidenced for the cages that incorporate a free-base porphyrin and a Zn(II) porphyrin, with a more pronounced splitting of the Soret band for the system with longer linkers. In these cages, following excitation of the Zn-porphyrin component, an almost quantitative energy transfer to the free-base unit occurs, with a rate 1.4 times faster in the cage with longer linkers (1.4 × 10[Formula: see text] s[Formula: see text] vs. 1.0 × 10[Formula: see text] s[Formula: see text]. This difference might reflect the more flattened conformation adopted by the cage equipped with longer and more flexible linkers, the latter allowing for a shorter interplanar distance between the porphyrins. The results are discussed in terms of classical and short-range energy transfer mechanisms.
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Gross, Ulrich, Shigeru Sassa, Karl Jacob, Jean-Charles Deybach, Yves Nordmann, Margareta Frank e Manfred O. Doss. "5-Aminolevulinic acid dehydratase deficiency porphyria: a twenty-year clinical and biochemical follow-up". Clinical Chemistry 44, n. 9 (1 settembre 1998): 1892–96. http://dx.doi.org/10.1093/clinchem/44.9.1892.
Testo completoAbstract (sommario):
Abstract 5-Aminolevulinic acid dehydratase (ALAD) activity in two patients with compound heterozygous 5-aminolevulinic acid dehydratase deficiency porphyria was studied over the last 20 years. The patients’ enzyme activity was <10% from 1977 to 1997. An acute crisis in each patient was successfully treated by infusion of glucose and heme arginate. After this therapy both urinary 5-aminolevulinic acid (ALA) and total porphyrins were diminished to 65% in patient B. In patient H, ALA was decreased to 80%, and total porphyrins were reduced to 15% after treatment with heme arginate and glucose. The patients remained free of symptoms after this therapy. Family studies of patient B showed cross-reactive immunological material (CRIM), in which the maternal mutation is CRIM(+), whereas the paternal mutation is CRIM(−). Incubation of erythrocyte lysates with ALA decreased porphyrin formation, whereas incubation with porphobilinogen produced porphyrin concentrations within reference values in both patients, confirming that ALAD activity is rate-limiting in these cells.
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Qi, Zhen-Li, Yun-Hui Cheng, Zhou Xu e Mao-Long Chen. "Recent Advances in Porphyrin-Based Materials for Metal Ions Detection". International Journal of Molecular Sciences 21, n. 16 (14 agosto 2020): 5839. http://dx.doi.org/10.3390/ijms21165839.
Testo completoAbstract (sommario):
Porphyrins have planar and conjugated structures, good optical properties, and other special functional properties. Owing to these excellent properties, in recent years, porphyrins and their analogues have emerged as a multifunctional platform for chemical sensors. The rich chemistry of these molecules offers many possibilities for metal ions detection. This review mainly discusses two types of molecular porphyrin and porphyrin composite sensors for metal ions detection, because porphyrins can be functionalized to improve their functional properties, which can introduce more chemical and functional sites. According to the different application materials, the section of porphyrin composite sensors is divided into five sub-categories: (1) porphyrin film, (2) porphyrin metal complex, (3) metal–organic frameworks, (4) graphene materials, and (5) other materials, respectively.
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Kano, Koji. "Molecular complexes of water-soluble porphyrins". Journal of Porphyrins and Phthalocyanines 08, n. 02 (febbraio 2004): 148–55. http://dx.doi.org/10.1142/s1088424604000143.
Testo completoAbstract (sommario):
Water-soluble porphyrins tend to form self-aggregates under certain conditions. The structure of the self-aggregate (H-type dimer, H-type higher aggregate, or J-aggregate) sensitively depends on the structure of the peripheral substituents at the meso-positions of the porphyrin. Water-soluble porphyrins also form relatively stable π-stacked complexes with various aromatics. Polar effects are important in complexation of anionic porphyrins with anthraquinonesulfonates. The results suggest that the main attractive interaction for formation of π-stacked complexes of water-soluble porphyrins is the σ-π interaction as claimed by Hunter and Sanders. Meanwhile, the aryl groups at the meso-positions of the water-soluble porphyrins are included by per-O-methylated β-cyclodextrin through van der Waals interactions to form extremely stable 1:2 complexes (porphyrin:cyclodextrin). Such a character of the water-soluble porphyrins can be applied to convenient preparation of supramolecular hetero-porphyrin arrays.