ISSN:0031-8655    

DOI:10.1111/j.1751-1097.1996.tb01852.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY

ISSN:0031-8655    

DOI:10.1111/j.1751-1097.1996.tb01853.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY

摘要:

Abstract—The purpose of this study was to investigate thein vitroandin vivospectral characteristics of the fluorescent pH‐sensitive probe Ws‐carboxyethylcarboxyfluorescein (BCECF) in different tissues and its fluorescence kinetics profiles. Thein vivostudy was performed on anesthetized adult Wistar rats. After intravenous administration (4.8 mg/kg), fluorescence spectra were recorded on the following tissues: skin, an isolated blood vessel and liver. Measurements performedin vitroon blood samples show modifications of the BCECF emission spectrum with a blue‐shift (10 nm) and a low fluorescence emission. Blood content greatly influences the pH measurement by increasing the I(490 exc, 530 em.)/I(470 exc, 530 em.) fluorescence ratio value (ratio of the fluorescence intensities at 530 nm following excitation at 470 nm and 490 nm) when the hematocrit is high. A 0.35 ratio difference is observed between a BCECF‐buffered solution and blood samples of 44% hematocrit. The emission spectra recorded on the skin are quite similar to the emission spectrum of BCECF in aqueous solution and are consistent with an extravascular localization of the dye a few minutes after injection. On the contrary, spectra recorded on the blood vessel and the liver are more similar than those recordedin vitroon high hematocrit solutions. Kinetic profiles in skin, liver and isolated blood vessels compared to the clearance obtained by blood sampling provide information about tissue perfusion. Then the variation ofin vivospectra in different tissues may be taken into account to measure tissue pH with special regard to the blood content of the illuminated area and the time range in which the measurement is

ISSN:0031-8655    

DOI:10.1111/j.1751-1097.1996.tb01854.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY

摘要:

Abstract—The fluoroquinolone antibiotics can induce skin photosensitivity in some patients and this has been ascribed to the generation of reactive oxygen species, such as singlet oxygen (O2[1Δg]). We have studied the photochemical properties of the different ionized forms of the fluoroquinolone norfloxacin upon complexation with Mg2+ and Ca2+ ions, as it is proposed that the antibiotic exists mainly as a complex in the blood plasma. We found that the norfloxacin cation (pH7.4, norfloxacin photobleaches and complexation to Ca2+ and Mg2+ increases the rate at which photobleaching occurs. Thus, both the pH of the medium and complexation with metal cations may affect the phototoxic potential of this an

ISSN:0031-8655    

DOI:10.1111/j.1751-1097.1996.tb01855.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY

摘要:

Abstract—Ultraviolet radiation produces free radicals in Skh‐1 mouse skin, contributing to photoaging and carcinogenesis. If a mouse model is a general indicator of free radical processes in human skin photobiology, then radical production observed in mouse and human skin should be directly comparative. In this work we show that UV radiation (Λ>300 nm, 14 μW/cm2UVB; 3.5 mW/cm2UVA) increases the ascorbate free radical (Asc.‐) electron paramagnetic resonance (EPR) signal in both Skh‐1 mouse skin (45%) and human facial skin biopsies (340%). Visible light (Λ>400 nm; 0.23 mW/cm2UVA) also increased the Asc.‐signal in human skin samples (45%) but did not increase baseline mouse Asc.‐, indicating that human skin is more susceptible to free radical formation and that a chromophore for visible light may be present. Using EPR spin‐trapping techniques, UV radiation produced spin adducts consistent with trapping lipid alkyl radicals in mouse skin (α‐[4‐pyridyl 1‐oxide]‐N‐tert‐butylnitrone/alkyl radical adduct; aN= 15.56 G and aH= 2.70 G) and lipid alkoxyl radicals in human skin (5,5‐dimethylpyrroline‐l‐oxide/alkoxyl radical adduct; aN= 14.54 G and aH= 16.0 G). Topical application of the iron chelator Desferal to human skin significantly decreases these radicals (±50%), indicating a role for iron in lipid peroxidation; Desferal has previously been shown to decrease radical production in mouse skin. This work supports the use of the Skh‐1 mouse as a predictive tool for free radical formation in human skin. These results provide the first direct evidence for UV radiation‐induced free radical formation at near physiological temperatures in human skin and suggest that iron chelators

ISSN:0031-8655    

DOI:10.1111/j.1751-1097.1996.tb01856.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY

摘要:

Abstract—A series of novel, unsymmetrically substituted metallophthalocyanines was synthesized, along with their symmetrically substituted analogs, and the effects of structure and metal substitution on their photophysical and photoredox properties were investigated. The macrocy‐cles were synthesized using a mixed‐condensation method followed by chromatographic separation of the resulting soluble products. They possess a catechol “active site” and three tert‐butyl groups for enhanced solubility. The ground‐ and excited‐state photophysical properties of the free‐base, Zn(II) and Pd(II) macrocycles were measured and compared with their symmetrically substituted (tetra[tert‐butyl]) analogs. The efficiency with which these macrocycles sensitize the formation of singlet oxygen was determined and discussed in the context of the excited‐state photophysical properties. Several examples of photoinduced electron transfer reactions with one‐ and two‐electron acceptors are demonstrated and discussed. These soluble molecules can be tuned to optimize their photochemical and redox properties by varying the central metal, axial ligands and other substituents, thereby providing a series of molecules for the investigation of photodynamic therapy and photoinduced ele

ISSN:0031-8655    

DOI:10.1111/j.1751-1097.1996.tb01857.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY

摘要:

Abstract—We examined the effects of broadband UVA radiation (320–400 nm) on a rat myeloid leukemia cell line–chlo‐roma (ChL). A Phillips face tanner model HB 171/A was used as a light source. Chloroma were irradiated through a 5 mm thick glass Alter that cut off all of the UVB contamination. The irradiances were measured, from 250 to 400 nm, with a well‐characterized and calibrated double‐grating spectroradiometer Optronic 742. The overall uncertainty of dose evaluation was estimated to be<15% (2s̀). The cells were irradiated with UVA doses of 4 and 8 J/cm2and cultured thereafter for 24 h. After this period of time, a marked decline up to 50% was observed in cell proliferation in UVA‐irradiated ChL cultures. The cell proliferation decline was found to be caused by simultaneously occurring G2/M phase cell cycle arrest and apoptosis in part of the UVA‐irradiated ChL population. Concomitantly, with the decline in cell proliferation, an increase was observed in the expression of the major histocompatibility (MHC) class I and II antigens. Because protein kinase C (PKC) is known to regulate cell proliferation, apoptosis and expression of MHC antigens, and because UVA was shown to regulate PKC activity/expression, we therefore examined whether UVA irradiation has any effect on the expression of isozymes of PKC. Western blots revealed that ChL express α, βI, δ, α, γ, and π isozymes of PKC and that expression of all isozymes declined 24 h after UVA irradiation (8 J/cm2). Finally, PKC activation in ChL by exposure to phorbol ester caused cell cycle arrest in G1 phase but did not induce apoptosis. This suggests that the previously shown UVA‐induced PKC activation in ChL might be responsible for the induction of MHC antigens but the simultaneously observed ChL apoptosis is likely to be mediated by PKC down‐regulation. All together, our results suggest that UVA, at irradiance levels that resemble the outdoor exposure, may have profound effects on the immune‐related properties of leukocytes. Thus, we speculate thatin vivothe immune functions of leukocytes passing through dermal capillaries might be altered by exp

ISSN:0031-8655    

DOI:10.1111/j.1751-1097.1996.tb01858.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY

摘要:

Abstract—The cyclobutane pyrimidine dimer (CPD) photolyase in fish cells is known to be regulated by environmental factors, such as light, hydrogen peroxide and growth inhibition. The induction of CPD photolyase by light in cultured goldfish cells was dependent on the wavelength of the light, and UVA and blue light had high inductive activity. The spectrum for CPD photolyase activity was different from that for the induction. Treatment with blue or yellow light for a short time, which did not induce any CPD photolyase, induced high CPD photolyase activity in the presence of the photosensitizers, TPPS (monosulfonatedmeso‐tetraphenyl porphine) and ALPS (aluminum phthalocyanine tetrasulfonate), respectively. These results suggest that the induction of CPD photolyase might be triggered by active oxygen produced by light and cellular photosensitizers. We also found that immediately after treatment with UVA, blue light or a photosensitizer in combination with light, cellular attachment to the substratum was enhanced, as was the CPD photolyase activity. Pretreatment with a flavonoid, quercetin, inhibited both photoinduction of CPD photolyase and enhancement of cellular attachment. Vitamin E inhibited only photoinduction of CPD photolyase activity. Treatment with H7, a strong inhibitor for protein kinase C, after light treatment inhibited photoinduction of CPD photolyase activity, but an analogue of H7, Ha1004, which is a weak inhibitor of protein kinase C, did not have such an eff

ISSN:0031-8655    

DOI:10.1111/j.1751-1097.1996.tb01859.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY

摘要:

Abstract—Ultraweak luminescence generated by sweet potato and nonpathogenicFusarium oxysporuminteractions associated with a defense response was detected by a photoncounting method using ultrahigh‐sensitive photodetectors. The time‐dependent intensity variation, the spectrum and the two‐dimensional imaging of the ultraweak luminescence are indicative of the defense response of the sweet potato toF. oxysporum.The production of ipomeamarone as a phytoalexin means thatF. oxysporuminduced the defense response in the sweet

ISSN:0031-8655    

DOI:10.1111/j.1751-1097.1996.tb01860.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY

摘要:

Abstract—Mutants ofSaccharomyces cerevisiaeaccumulating uroporphyrin (UP) or protoporphyrin (PP) were used as a model for thein vivophototoxic effect of porphyrins observed in the human skin photosensitivity associated with porphyrias (porphyria cutanea tarda and erythropoietic protoporphyria). We have found that UP is localized in vacuoles and PP is present in all compartments except vacuoles in yeast cells. Endogenous PP is much more effective as a photosensitizer of yeast cells than UP. Protoporphyrin action is strictly dependent on the presence of oxygen. In contrast, UP displays a phototoxic effect even if oxygen is not present in the suspension, implicating a free radical mechanism that operates in anaero‐biosis upon photosensitization by UP. Catalase or superoxide dismutase deficiency affects photosensitization by UP. A possible mechanism of UP photosensitizing activity is discus

ISSN:0031-8655    

DOI:10.1111/j.1751-1097.1996.tb01861.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY