Porphyrins concentrations

Compounds 1,2,3,5,10,11,12,13,14 were dissolved in EPIP (diethyl ether, petroleum ether, isopropanol 5 5 2)whereas compounds 4,6,7,8,9,15 were dissolved in THF-DE (tetrahydrofurane, diethyl ether 1 1). These solvent mixtures can be frozen as glassy samples at 77 K. The absorption spectra were recorded on a standard spectrophotometer SF-10 or Beckman-5270. The measurements of fluorescence excitation and emission spectra were made with the aid of a spectrofluorometer SLM-4800 with automatic correction of spectral response. Fluorescence lifetimes were measured with the aid of a pulse fluorometer PRA-3000. Magnetic circular dichroism (MCD) measurements were carried out in a 8 kG magnetic field using a JASCO J-20 circular dichrometer. Triplet state formation was observed for investigated compounds at the experimental set up, whose detailed description can be found in our paper (27). The optical experiments were carried out with a porphyrin concentration of 4.10- - 4.10 mol.l". In NMR investigations (Bruker WM-360) we used higher concentrations ( 5.10" raol.l ) and dried solvents (CDCl, C 2 and toluene-d0). 

It should be noted that the existence of different centers Is also found in covalently-linked dimer 11. Moreover, the analysis of all data obtained for dimers points clearly towards the efficient transfer of the excited singlet state energy from two centers of compound 1 to two acceptor centers of compound 2 in dimers (14,30). Increase In the porphyrin concentration by 300-700 times (say, for compounds 1 and 2) does not cause additional changes In electronic spectra as against diluted solutions. If the results obtained from temperature experiments (Fig. 2b) and measurements of fluorescence lifetimes In different bands are taken Into account, one may conclude that the additional centers observed In... 

Table 7.3.2 Standard (Std) solutions used for the determination of urinary porphyrin concentration. 1ST Deuteroporphyrin IX (2,4-bis-glycol)...

Symptomatic porphyria patients usually show urinary porphyrin concentrations that exceed the upper limit of normal by twofold or more. Table 7.3.1 lists most of the diagnostic abnormalities of the different porphyrias. Only slightly abnormal or even fully normal values may be seen in asymptomatic patients. But alcohol overconsumption, enzyme-inducing drugs, stress, and other factors may also induce slightly abnormal values that should not be mistaken for porphyria. A characteristic sign for such a secondary effect is the isolated elevation of coproporphyrin, especially of its... 

A 40-year-old white woman with skin type II who for 4 months had been taking a low-dose combined oral contraceptive based on levonorgestrel and ethinylestradiol developed skin fragility on her sun-exposed forearms, with blisters, erosions, and scars. Histology led to a diagnosis of pseudoporphyria, since porphyrin concentrations were not raised. After the oral contraceptive was withdrawn the lesions healed slowly, despite continuing sun exposure. 

Propofol is regarded as being safe in patients with different types of porphyria. This is the first reported case in which propofol had a possible role in causing raised porphyrin concentrations perioperatively. However, severe illness can also precipitate porphyria, so the association with propofol may have been incidental. 

Dew points were also measured using the procedure described above, except that the disappearance of the liquid phase was observed as solvent was added to the view cell. Dew point measurements were limited by low porphyrin concentrations in the gas phase, which required loading very small amounts of porphyrin into the cell. 

Fig. 11 CD increase of the phenylalanine imprinted aggregates (CD intensity variation) vs the added porphyrin concentration (each aliquots is 0.25 pM). Inset CD spectra before (grey curve) and after five additions of the individual porphyrins. Modified from [45]...

Under our experimental conditions, the initial copper ( V lmM) and quinoline ( 1-lOmM) concentrations are in excess of the porphyrin concentration ( 80yM). Thus, taking [Qff ] 2ICuP],... 

Their best agent was the cobalt(lll) complex of 5,10-bis(4-methylpyridinium)-15,20-bis-(4-nitrophenyl)porphyrin, which had an SER of 1.22 at 50 pM towards CHO hypoxic cells. This complex was actually the most promising of over 50 studied. Using this CHO tumor cell line and identical XRT conditions (i.e. oxic and hypoxic lOOpM porphyrin concentration 16 Gy), O Hara et al. found that the cobalt(III) complexes, CoTPPS and COTMPyP, exhibited a weak sensitization effect (SER = 1.05-1.22, with or without serum-containing medium). These workers also concluded that the introduction of nitro and/or positively charged substituents on the porphyrin periphery serves to augment the net radiosensitization effect for these kinds of Co(lll) porphyrins [153,154]. Unfortunately, even when enhanced in this way, the net sensitization effect is small. 

A 75-year-old man with prostatic carcinoma took flutamide for 18 months and developed blisters on the back of the hands and fingers after exposure to the sun (4). The bullae were associated with skin fragility and atrophic scarring. Histopathology and direct immunofluorescence showed ultrastructural features similar to those described in porphyria cutanea tarda. However, porphyrin concentrations in the urine and blood were normal. Flutamide was withdrawn and the lesions healed, without relapse after 11 months. 

The HDM reaction was carried out at industrial conditions, 553 K and 9.0 MPa Hj pressure. At certain time intervals a liquid sample was taken from the autoclave and analysed ex-situ with UV-Vis spectroscopy to determine the porphyrin concentrations (9). 

In PCT, excretion and plasma porphyrin concentrations return to normal during remissionj with the proportions of individual porphyrins in urine and feces remaining abnormal for longer than total porphyrin concentrations. Thus in a patient whose skin lesions have healed, and whose total urinary and fecal porphyrin concentrations are normal, determination of individual porphyrins may reveal the diagnosis. The plasma fluorescence scan in VP and fecal coproporphyrin-III excretion in HCP remain abnormal for many years after clinical remission. 

AH samples must be protected from light urinary porphyrin concentrations can decrease by up to 50% if kept in the light for 24 hours. Urinary porphyrins and PBG are best analyzed in fresh, random (10 to 20 mL) samples collected without preservative. Very dilute urine (creatinine less than 4 mmol/L) is unsuitable for analysis. 

Increased total fecal porphyrin concentration requires further investigation by fractionation, identification, and quantification of individual porphyrins using a technique, such as HPLC, that resolves coproporphyrin I and III isomers. Porphyria should never be diagnosed on the basis of raised total fecal porphyrin alone. 

Reference intervals are given in Table 32-3. Total erythrocyte porphyrin concentrations are increased in EPP, CEP, the rare homozygous variants of the autosomal dominant porphyrias, iron deficiency, hemolytic anemia, some other forms of anemia, and lead poisoning. A normal total porphyrin concentration excludes the diagnosis of EPP. Distinction between EPP and other causes of increased erythrocyte total porphyrin concentration requires differentiation between protoporphyrin and its zinc chelate because the acidic condition of this assay dissociates the zinc chelate and provides only a measure of total porphyrin. 

The plasma porphyrin concentration may be increased in conditions in which porphyrin excretion is impaired, such as renal failure and cholestasis. Although plasma porphyrin concentrations are usually higher in chronic renal failure with PCT than in renal failure alone, unequivocal diagnosis of PCT in this situation is best achieved by fecal porphyrin analysis or fractionation of plasma porphyrins by HPLC. ... 

Fig. 8.8. ECD (top) and visible absorption (bottom) spectra of (A) DNA-Cu(ll)TMPyP (B) DNA-Fe(lll)TMPyP and (C) DNA-TMAP complexes in the Soret spectral region at different c(DNA)/ c(porphyrin) concentration ratios. UV spectra given as inset. (Reprinted with permission from J. Novy, M. Urbanova, K. Volka, Collect. Czech. Chem. Commun. 2005, 70, 1799-1810. Copyright 2005 Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic.)...

Dimerization of protoporphyrin IX in aqueous solution has been studied by fluorinietric techniques. Fluorescence intensity increase linearly with the concentration of protoporphyin in solution up to 0.05 pM. Beyond this concentration, the intensity is no more linear and goes downward as the result of the porphyrin aggregation. In an organic solution, the fluorescence intensity of porphyrin increases linearly with the increase of the porphyrin concentration (Margalit et al. 1983). 

Figure 2 Bleaching (degradation) of iron me5t -tetraphenylporphyrin and compound 2 by m-chloroperbenzoic acid at 1 mM. Porphyrin concentration ci lOpM. Absorbance measured at the Soret band...

Figure 9-14. Oxygen and nitrogen permeability coeffieients (/ 02 and Pn2) for the cobalt porphyrin-polymer complex menftrane. The cob

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