摘要:

Abstract—Using pulse radiolysis techniques, 3 azapropazone and 3 phenylbutazone derivatives all structurally related to the potentially photosensitive anti‐inflammatory drug, azapropazone, have been reacted with the free radical oxidants N3, Br2‐and (SCN)2‐as well as with e‐aqa strong reductant. It is demonstrated that for 5 derivatives, azapropazone (Az), 2‐[a‐Carboxy‐valeryll‐3‐dimethylamino‐7‐meth1‐1,2‐dihydro‐1,2,4‐benzotriazine (Mi307), phenylbutazone (PB), oxyphenylbutazone (OPB), and ketophenylbutazone (KPB), N3‐and Br2‐appear to reactviaa one‐electron removal process. For the other derivative, 8‐hydroxy azapropazone (8‐OH‐Az), Nj and (SCN); oxidiseviaa one‐electron process, while Br2‐probably fqrms a free radical adduct.The absolute spectra of the one‐electron oxidised and reduced transient species for all six derivatives are thus given in this work and are a basis to the un

ISSN:0031-8655    

DOI:10.1111/j.1751-1097.1988.tb02837.x

出版商:Blackwell Publishing Ltd    

年代:1988

数据来源: WILEY

摘要:

Abstract—The dynamic interaction with DNA of two representative anthracyclines, daunomycin and 5‐iminodaunomycin, differing in the redox properties, DNA affinity and cardiotoxicity, has been characterized by laser time‐resolved fluorescence decay. The free drug fluorescence decay is mono‐exponential for daunomycin in both phosphate and TRIS buffer and becomes biexponential in the case of 5‐iminodaunomycin when the phosphate buffer is used. In the presence of DNA, daunomycin excited with a mode‐locked Ar laser at 364 nm shows a three‐exponential fluorescence decay with time constants T1=2.92 ns, T2= 1.42 ns, T3=0.31 ns. The first lifetime refers to the decay of the excited state of the chromophore bound on the DNA backbone, whereas T2and T3are assigned to two different conformations of the intercalation complex. An estimate of the molar extinction coefficient and the relative quantum yield of the variously bound drug is made. The 5‐iminodaunomycin fluorescence decay lifetime is less sensitive to the nature of the environment probably because, being a poorer intercalator, it binds more easily on the phosphate backbone and thus the electronic perturbation resulting from the binding is not as strong as in the cas

ISSN:0031-8655    

DOI:10.1111/j.1751-1097.1988.tb02838.x

出版商:Blackwell Publishing Ltd    

年代:1988

数据来源: WILEY

摘要:

Abstract—The electro‐oxidation of Ni(II)TVyPP and Zn(II)TVyPP in organic solvent (CH2‐C12) leads to the deposition ofca.500 monolayer equivalents of electroactive porphyrin films which have been characterised by cyclic voltammetry. The films are stable towards organic solvents and aqueous acids and bases, but are removed by treatment with hot concentrated acids. The Laser Raman spectrum of NiTVyPP film indicates that all the four vinyl groups are saturated. No film is formed if the metal and not the ring is oxi

ISSN:0031-8655    

DOI:10.1111/j.1751-1097.1988.tb02839.x

出版商:Blackwell Publishing Ltd    

年代:1988

数据来源: WILEY

摘要:

Abstract—The relative reactivity of singlet molecular oxygen, 02(1Δg), α‐,β‐,Γ‐and δ with ‐tocopherol (vitamin E) was investigated using microwave discharge generation as a uniquely clean source of singlet oxygen and using a hydrocarbon solvent to approximate the membrane environment. The relative efficiencies of the tocopherols for O2(1Δg) were found to decrease in the order: D‐α‐tocopherol>D‐β‐tocopheroI>D–Γ‐tocopherol>D‐δ‐tocopherol. The reaction products in all cases were found to be mixtures of quinone and quinone epoxides apparently resulting from decomposition of the prim

ISSN:0031-8655    

DOI:10.1111/j.1751-1097.1988.tb02840.x

出版商:Blackwell Publishing Ltd    

年代:1988

数据来源: WILEY

摘要:

Abstract—Triplet‐triplet absorption spectra, intersystem crossing quantum yields, fluorescence lifetimes, and fluorescence quantum yields of 5‐methoxypsoralen (5MOP) in dioxane‐water mixtures are reported. The fluorescence and triplet formation quantum yields depend strongly on the water content in the mixtures, increasing up to maximum values which are, respectively, twentyfold and fivefold larger than in dioxane and then decreasing. This behaviour is essentially due to the variation of the internal conversion rate constant. With these solvent mixtures it is possible to emulate the dielectric response of 5MOP photophysical parameters in other media, such as in biological model systems and in human blood lipoproteins. The biological importance of these results is di

ISSN:0031-8655    

DOI:10.1111/j.1751-1097.1988.tb02841.x

出版商:Blackwell Publishing Ltd    

年代:1988

数据来源: WILEY

摘要:

Abstract—Different methods for measurements of UV‐radiation of various light sources are quantitatively compared: direct measurements, based on detectors of known responsivity, as well as indirect measurements, based on a spectral irradiance calibration. The optical arrangement of an accurate spectroradiometric equipment, and the structure and parameters for a new type of cosine corrected detector for the measurement of actinic radiation are described, too. The measurements of actinic radiation with commercial devices are affected by great relative errors.A standard for natural irradiance will allow a comparison of weighted irradiances and threshold irradiations with natural insolation and with artificial UV radiation. The risk of existing irradiation apparatuses will be calculable by this compari

ISSN:0031-8655    

DOI:10.1111/j.1751-1097.1988.tb02842.x

出版商:Blackwell Publishing Ltd    

年代:1988

数据来源: WILEY

摘要:

Abstract—Carbon‐14‐labeled hematoporphyrin ([14C]HP) was synthesized by two methods, (i) Using anin vitroavian whole‐blood system, [14C]protoheme was obtained biosynthetically by incorporating [4C]aminolevulinic acid into the porphyrin ring structure. Subsequently, the [14C]protoheme was converted to [4C]HP by standard procedures, (ii) By adopting several well‐characterized chemical reactions, deuteroporphyrin was treated with [14C]acetyl chloride, giving [14C]diacetyl deuteroporphy‐rin which was readily reduced and hydrolyzed to [14C]HP (with thecarbon–14 label on the hydroxyethyl side‐chains). These two methods are simple and afford good yields of [14C]HP with moderate to high specific activities.The [14C]HP was then treated with acetic acid/sulfuric acid followed by sodium hydroxide to give [14C]HPD. Upon gel‐ and ultra‐filtration, the [14C]HPD was enriched in the so‐called tumor‐localizing fraction of HPD, giving [14C]PII with specific activities of 0.4 Ci/mol (biosynthesis) and 10 Ci/mol (chemical synthesis). These [14C]PII preparations were equivalent with respect to chromatographic and spectrophotometric characteristics, as well as tumoricidal photodynamic activity in the DBA/2 Ha‐DD mouse: SMT‐F tumor system, to the unlabeled commercial product Photofrin™II. The distribution of [14C]PII in mouse tissues was in close agreement to that previously reported, after adjustment for dose, for [14C]HPD biosynthetically labeledin vivo(Gomer and Dougherty, 1979), as well as for Photofrin™II, where tissue levels were determined spectrophotometrically after extraction (D

ISSN:0031-8655    

DOI:10.1111/j.1751-1097.1988.tb02843.x

出版商:Blackwell Publishing Ltd    

年代:1988

数据来源: WILEY

摘要:

Abstract—For a variety of chemically defined, synthetic and natural porphyrins, the tendency for self aggregation, binding to serum albumin, distribution coefficient betweenoctanol–1 and water and uptake in V79 Chinese hamster cells have been determined. A strong correlation was found between cell uptake and distribution into octanol. None of the other factors could be correlated with cell uptake. These observations might have an impact on the use of porphyrins in photodynamic and boron neutron capture therapy of tum

ISSN:0031-8655    

DOI:10.1111/j.1751-1097.1988.tb02844.x

出版商:Blackwell Publishing Ltd    

年代:1988

数据来源: WILEY

摘要:

Abstract—The survival of the planarianDugesia dorotocephalawas measured following treatment with germicidal ultraviolet (UV) radiation, with the DNA photosensitizer 8‐methoxypsoralen (8‐MOP) plus near UV radiation, or with the cytoplasm photosensitizer erythrosin plus visible radiation. The typical morphological response of an irradiated animal was lysis, with the head being the most sensitive part. All the survival curves had substantial shoulders. Treatments whose primary target was likely to be DNA (UV irradiation or 8‐MOP plus near UV irradiation) resulted in lysis of part of the planarian population which commenced 24 h or more after treatment and continued over several days. The treatment whose primary target was likely to be the membranes of the planarian (erythrosin plus visible irradiation) resulted in lysis mostly during the first few hours after treatment. Thus an easily discerned endpoint, lysis, can be used forD. dorotocephalato evaluate photosensitizing compounds, where the kinetics of lysis may differentiate among compounds whose modes of action are di

ISSN:0031-8655    

DOI:10.1111/j.1751-1097.1988.tb02845.x

出版商:Blackwell Publishing Ltd    

年代:1988

数据来源: WILEY

摘要:

Abstract—Photofrin II (PF‐II) is the commercial name of the active photosensitizer which is used in photodynamic therapy of cancer. The effect of the composition of lipid membranes on the binding of PF‐II was studied and compared to hematoporphyrin derivative (Hpd), which is a complex mixture of porphyrins and from which PF‐II is separated. We find that increasing the content of cholesterol in the bilayer decreases the partitioning of PF‐II into the bilayer, similar to what we have found earlier with Hpd. However, inserting DMPC or DPPC into the membrane, which was shown to decrease the binding of Hpd, causes the opposite trend with PF‐H. A membrane fluidizer such as benzyl alcohol also has different effects on the membrane binding of Hpd and PF‐II. The rate of binding of PF‐II to a lipid membrane is about 10 times lower than that of Hpd. These results as well as I‐quenching of the fluorescence of the two porphyrins indicate that PF‐II is immersed less homogeneously and deeper in the bilayer than Hpd. The unique additive‐dependent binding of PF‐II to lipid membranes calls for care in using Hpd as

ISSN:0031-8655    

DOI:10.1111/j.1751-1097.1988.tb02846.x

出版商:Blackwell Publishing Ltd    

年代:1988

数据来源: WILEY