摘要:

AbstractThe phenomena of the high affinity of porphyrins to the human serum proteins, albumin, high‐density lipoproteins (HDL) and low‐density lipoproteins (LDL) is well established. Yet, evaluation of the activities of these proteins as endogenous porphyrin carriers, especially with respect to receptor‐mediated porphyrin uptake into tumor cells, the merits of which are still in dispute, requires more quantitative protein‐porphyrin binding data. As a continuation of previous studies on this issue, the binding of several porphyrin systems to each of the three proteins, employing previously developed spectral methodologies, was studied. The specific systems reported here are hematoporphyrin ester (HPE), which is a novel hematoporphyrin derivative (HPD)‐like system, two porphyrin trimers (denoted O1 and O2) and a porphyrin dimer (denoted O3) isolated from HPE. Human serum albumin (HSA) was found to have a single high‐affinity site for the monomeric components of HPE, with an equilibrium binding constant of 3.6 × 106. The equilibrium parameters determined for the binding of the three HPE‐isolated oligomers to each of the serum proteins are: (1) Binding constants (Kb') of 2.3 × 106, 6.9 × 104and 1.5 × 104and number of sites per protein molecule (n) of 3, 1 and 5, for the binding of 01, 02 and 03, respectively, to HSA. (2) Kb’values of 15.5 × 103, 15.3 × 103and 6.6 × 103and n values of 1, 2 and 2, for the binding of O1, O2 and O3, respectively, to HDL. (3)Kb’values of 3.3 × 103, 2.28 × 104and 8.0 × 103and n values of 50, 20 and 16 for the binding of O1, O2 and O3, respectively, to LDL. These data are direct and clear support not only for the high affinity of porphyrins to serum proteins but specifically of stable oligomers that have been assigned critical roles in the photodynamic treatment of tumors. Of the three proteins, LDL is clearly the best camer, providing the highest drug payload with a moderate affinity (enough to bind and not too much to prevent release). These data are suggested to be promising for the postulated role of LDL in porphyrin uptake into tumor cells and to be useful in the future as benchmarks

ISSN:0031-8655    

DOI:10.1111/j.1751-1097.1993.tb04943.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY

摘要:

AbstractWe have investigated the photosensitized monomerization of thecis,syn‐cyclobutane dimer of 1,3‐di‐methylthymine using riboflavin tetraacetate and a 5‐deazaflavin derivative as photosensitizer. Although little monomerization of the dimer is induced by photoexcitation of the flavins in the absence of any additives, the flavins can function as an efficient photosensitizer in the presence of magnesium perchlorate. Mechanistic studies involving spectroscopic, quantum‐yield and flash‐photolysis measurements demonstrated that the photosensitized monomerization exclusively proceeds through electron transfer from the dimer to the triplet flavins complexed with Mg2+. The effects of magnesium perchlorate are compared with those on the chloranil‐photosensitized monomerization and also with the effects of HClO4on the flavin‐photosens

ISSN:0031-8655    

DOI:10.1111/j.1751-1097.1993.tb04944.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY

摘要:

AbstractBenzo[a]pyrene tetrol (BPT) was used as a fluorescent probe to investigate the nature of antigen binding by two different monoclonal antibodies (MAb) that recognize a variety of derivatives ofanti‐7,8‐dihydroxy‐9,10‐epoxy‐7,8,9,10‐tetrahydrobenzo[a]pyrenes (BPDE). Fluorescence line‐narrowed spectra of the physical complexes of BPT formed with antibodies 8E11 and 3C3 were recorded at 4 K by employing vibronic excitation into the S, electronic state. The frequencies of the vibrational modes of the S1state were only marginally affected, though changes in relative intensities of some bands were observed. Fluorescence spectra recorded at 77 K by excitation into the S2state showed that the (0,0) fluorescence emission of BPT was shifted to red on complex formation. Intensity ratios of the (0,0) band and the main vibrational band at 1300 cm‐1were used to assess the degree of interior binding of the chromophore. Quenching studies with acrylamide were employed to designate the complexes as type I, solvent inaccessible, or type II, solvent accessible. These studies also indicated that antibody 3C3 complexes tend to be more heterogeneous compared to the 8E11 complex. Deuterated BPT‐d‐12 also formed complexes with both antibodies, however, with different

ISSN:0031-8655    

DOI:10.1111/j.1751-1097.1993.tb04945.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY

摘要:

AbstractThe Philips TL01 narrow‐band (311–313 nm) fluorescent lamp provides effective phototherapy for psoriasis and atopic eczema while emitting less erythemogenic radiation than conventional broad‐band (e.g. Philips TL12; 270–350 nm) sources. We studied the potency of TL01 and TL12 radiation to induce edema and sunburn cells (SBC) and to photoisomerize naturally occumngtrans‐urocanic acid (UCA) tocis‐UCA in hairless mouse skin.Cis‐UCA has immunosuppressive properties and is a putative mediator of UV‐induced suppression of immune responses. For each source, there was UV dose dependence for all three responses. Within the dose ranges used, the potency ratio of TL12: TL01 radiation to induce equivalent edema and SBC was about 6:1. However, the potency ratio to induce cis‐IJCA was less than 2.3:1. Therefore, at a given level of edema or SBC induction, TL01 was more efficient than TL12 at UCA photoisomerization. The TL01 induction of immunomodulatingcis‐UCA, while causing minimal skin injury, may relate to the therapeutic efficacy of this source in skin conditions with an immu

ISSN:0031-8655    

DOI:10.1111/j.1751-1097.1993.tb04946.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY

摘要:

AbstractMethylene blue is a very strong photoactive dye that has an absorption peak (668 nm) that corresponds well to a popular low‐cost diode laser. However, it has not been used in photodynamic tumor therapy and immunodiagnostics because it cannot be covalently coupled to protein. Therefore, methylene blue derivatives having a succinimido or maleimido functional group were synthesized and coupled to antibody, serum albumin and transfemn proteins. Incorporation of dye into antibody protein at high ratios (more than three per molecule) caused precipitation and loss of antibody activity. Inclusion of one or more carboxylic acid residues in the methylene blue derivative before coupling to protein alleviated the precipitation problem, and up to 36 methylene blue dye molecules could be attached to an antibody fragment using bovine serum protein as a carrier. Methylene blue derivatives and protein complexes formed from them oxidized luminol when stimulated with red light. The new dye conjugates were used in an optically pumped chemiluminescence immunoassay for α‐fetoprotein. These compounds and techniques should also be useful for photodynamic tumor therapy where it is desired to attach a red‐absorbing photoactive dye to antibody p

ISSN:0031-8655    

DOI:10.1111/j.1751-1097.1993.tb04947.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY

摘要:

AbstractThein vitrocell survival, localization and ultrastructural changes following irradiation were examined in 9L glioma cells sensitized with a new photosensitizer, lysyl chlorin p6(LCP). In clonogenic assays, LCP was 10–100‐fold more phototoxic than photofrin II on a μg/mL basis. Lysyl chlorin p6uptake was blocked when cells were incubated at 2°C. In view of the chemical properties of LCP, this finding indicates that uptake probably occurred through the endocytic pathway. Fluorescence studies showed LCP localized in a region of the endocytic compartment similar in size, shape and distribution to that labeled by lucifer yellow CH (LY), as well as localizing diffusely throughout the perinuclear cytoplasm. Cells stained with both LY and LCP, however, had distinctly separate regions of staining. Lysyl chlorin p6localization differed from that of fluorescent probes labeling the mitochondria, Golgi apparatus and endoplasmic reticulum. Ultrastructural changes at both 2 and 30 min after laser irradiation were similar. Mitochondria were often condensed or swollen and also had constrictions and cytoplasmic invaginations. The Golgi apparatus, perinuclear space and rough endoplasmic reticulum (RER) were dilated. These data demonstrate that LCP localizes in a portion of the endosomal compartment, but that morphologic damage initially occurs in the mitochondria, Golgi apparatus an

ISSN:0031-8655    

DOI:10.1111/j.1751-1097.1993.tb04948.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY

摘要:

AbstractThe relaxation of rabbit aorta rings induced by low‐power laser radiation was investigatedin vitroto determine the location of the chromophore(s) responsible for this response and evaluate possible mechanisms. An action spectrum for relaxation was measured on rabbit thoracic aorta rings precontracted with norepinephrine. The decrease in isometric tension was measured during exposure to laser light (351–625 nm) deliveredviaa fiber optic to a small spot on the adventitial surface. The shortest UV wavelength (351 nm) was 35‐fold more effective than 390 nm and 1700‐fold more effective than 460 nm. Ultraviolet wavelengths also produced greater maximum relaxation (0.40–0.45) than visible wavelengths (0.20–0.25), suggesting that photovasorelaxation involves more than one chromophore.The adventitial layer was not necessary for photovasorelaxation, indicating that the light is absorbed by a chromophore in the medial layer. The same degree of relaxation was obtained on rings without adventitia when either one‐half of the ring, or a small spot was irradiated indicating that communication between smooth muscle cells spreads a signal from the area illuminated to the entire ring.The mechanism for photovasorelaxation was investigated using potential inhibitors.N‐monomethyl‐l‐arginine andN‐amino‐L‐arginine, inhibitors of nitric oxide synthase, did not alter photovasorelaxation nor did indomethacin, an inhibitor of cyclooxygenase, and zinc protoporphyrin, an in

ISSN:0031-8655    

DOI:10.1111/j.1751-1097.1993.tb04949.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY

摘要:

AbstractThe capability of human promyelocytic leukemia cells HL60 to be induced to differentiate to various stages along the monocytic or myelocytic pathway was exploited for investigation of the uptake of selected photo‐sensitizers by diverse types of cells of the same origin. The results showed that there was no substantial difference in photofrin uptake between noninduced HL60 cells, immature monocytes, immature neutrophils and cells differentiated along the eosinophilic pathway. In contrast, HL60 cells differentiated into macrophages (HL609) exhibited markedly increased photofrin uptake, which was further enhanced by their pretreatment with bacterial lipopolysaccharide. Similar results were obtained with other photosensitizers tested: di‐and tetrasulfonated aluminum phthalocyanines (AIPcS2and AIPcS4), tetrasulfonated zinc phthalocyanine (ZnPcS4), tetraphenylporphine tetrasulfonate (TPPS4) and benzoporphyrin derivative monoacid (BPD). Despite marked differences in the state of self‐aggregation and other chemical properties of these compounds, the degree of their preferential uptake by HL60 PH cells showed very little variation. In a typical experiment, the uptake of these photosensitizers by HL60 PH cells was four to five times higher than the uptake by noninduced HL60 cells. In addition to the fluorometric assay employed in most of the experiments, cellular concentration of AlPcS4was determined by measurement of elementary aluminum using atomic absorption spectro

ISSN:0031-8655    

DOI:10.1111/j.1751-1097.1993.tb04950.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY

摘要:

AbstractThe potential to induce non‐nuclear changes in mammalian cells has been examined for (1) UVA1 radiation (340–400 nm, UVASUN 2000 lamp), (2) UVA + UVB (peak at 313 nm) radiation (FS20 lamp), and (3) UVC (254 nm) radiation (GI5T8 lamp). The effects of irradiation were monitoredin vitrousing three strains of L5178Y (LY) mouse lymphoma cells that markedly differ in sensitivity to UV radiation. Comparisons were made for the effects of approximately equitoxic fluences that reduced cell survival to 1–15%. Depending on the cell strain, the fluences ranged from 830 to 1600 kJ/m2for the UVASUN lamp, 75 to 390 J/m2for the FS20 lamp and 3.8 to 17.2 J/m2for the G15T8 lamp. At the exposure level used in this study, irradiation with the UVASUN, but not the FS20 or G15T8, lamp induced a variety of non‐nuclear changes including damage to cytoplasmic organelles and increased plasma membrane permeability and cell lysis. Cell lysis and membrane permeabilization were induced by the UVA1 emission of the UVASUN lamp, but not by its visible + IR components (>400 nm). The results show that the plasma membrane and other organelles of LY cells are highly sensitive to UVA1 but not to UVB or UVC radiation. Also UVA1, but not UVB or UVC radiation, causes rapid and extensive lysis of LY cells. In conclusion, non‐nuclear damage contributes substantially to UVA cytotoxicity in all three strains of

ISSN:0031-8655    

DOI:10.1111/j.1751-1097.1993.tb04951.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY

摘要:

AbstractEvidence for the increased immunogenicity of mastocytoma cells (P815) treated with 8‐methoxypsoralen (8‐MOP) and long‐wavelength ultraviolet radiation (UVA) is presented. A highly tumorigenic clone (P1) became much less tumorigenic (tum‐) after repetitive phototreatments with 8‐MOP (16 ng/mL) and UVA (1 J/cm2). The yield of tum‐clones was proportional to the number of phototreatments. In a pilot study in which P1 cells were treated with three successive rounds of 8‐MOP/UVA, one clone out of 73 was tum‐. In a second series of experiments, the P1 cells were treated 10 times and 4 out of 100 clones were much less tumorigenic. When some of the tum‐clones were administered intraperitoneally to DBA/2 mice, significant protection against challenge with the original P1 clone was observed. In addition, the transfer of immune cells from tum‐‐treated mice allowed the transfer of resistance to other tum‐clones to immunosuppressed mice (650 rad). These results are consistent with earlier literature showing the potent mutagen,N‐methyl‐N′‐nitrosoguanidine, led to mutations in P1 that altered the expression of new surface antigens, which stimulated the murine immune system such that there was also cross recognition of shared antigens on untreated P1 cells used to challenge the immunized mice. The increased immunogenicity that resulted from the less mutagenic 8‐MOP/UVA treatment may arise by a similar mechanism and may be responsible in part for the efficacy of 8‐MOP/UVA photochemotherapy for the tre

ISSN:0031-8655    

DOI:10.1111/j.1751-1097.1993.tb04952.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY