bluuebunny/crossref_metadata_2025 huggingface dataset:
In vivo SPECTROPHOTOMETRIC EVALUATION OF NEOPLASTIC AND NON‐NEOPLASTIC SKIN PIGMENTED LESIONS. II: DISCRIMINANT ANALYSIS BETWEEN NEVUS AND MELANOMA
Authors: Marchesini R. , Cascinelli N. , Brambilla M. , Clemente C. , Mascheroni L. , Pignoli E. , Testori A. , Venturoli D. R.
Published: January 2008

Abstract— Reflectance spectrophotometry from 420 to 780 nm on 31 primary melanoma and 31 benign nevi has been performed by using an external integrating sphere coupled to a spectrophotometer. Measurements show that reflectance spectra of melanoma and nevi manifest dissimilar patterns. From these spectra four variables, whose physical and/or physiological meanings remain to be investigated, have been derived. All of them are significantly different when compared between melanoma and nevi. A discriminant function between the two groups of lesions has been determined by using a stepwise discriminant analysis, resulting in a test with a sensitivity of 90.3% and a specificity of 77.4%. This method of discrimination between melanoma and nevi seems to have a discriminating power almost equal to that of a clinical judgement from a specialized medical doctor, thus suggesting a new method for screening skin pigmented lesions.
In vivo EVALUATION OF PHOTOPROTECTION AGAINST CHRONIC ULTRAVIOLET‐A IRRADIATION BY A NEW SUNSCREEN MEXORYL® SX*
Authors: Fourtanier A. , Labat‐Robert J. , Kern P. , Berrebi C. , Gracia A. M. , Boyer B.
Published: January 2008

Abstract— In a previous study on the hairless mouse it was shown that sub‐erythemal doses of pure UV‐A enhanced the numerous changes normally observed during chronological aging. A new sunscreen (a bis‐benzylidene campho sulfonic acid derivative) has been synthesized in our research laboratory (Λmax: 345 nm, ε: 47000). Its photoprotective properties against UV‐A induced damages were assessed in our mouse model. Three month old albino hairless mice were exposed for 1 y to suberythemal doses (35 J/cm2) of UV‐A obtained from a xenon source filtered through a WG 345 filter. One group of animals was exposed untreated, the other received a formulation containing 5% of the sunscreen prior to irradiation. At the end of the study the cutaneous properties of protected mice were compared to those of unprotected animals and to 3 and 15 month old unirradiated controls. We found that the visible changes induced by UV‐A irradiation were mainly sagging and wrinkling. Histological and electron microscopic alterations consisted of hyperkeratosis, increased density of elastic fibers with alteration of fiber orientation and increased glycosaminoglycan deposits. Biochemical changes consisted of decreases in total collagen and collagen hydroxylation and increases in both collagen III/I + III ratio and fibronectin biosynthesis. All these changes were reduced or abolished by the sunscreen.
PHARMACOKINETICS OF FLUORESCENT POLYPORPHYRIN PHOTOFRIN II IN NORMAL RAT TISSUE AND RAT BLADDER TUMOR
Authors: Baumgartner R. , Fuchs N. , Jocham D. , Stepp H. , Unsöld E.
Published: January 2008

Abstract—The transient behavior of the molecular components responsible for fluorescence emission of the photosensitizing polyporphyrin Photofrin II has been studied quantitatively in the liver, small intestines, bladder and muscles of rats. Relative concentrations of the substance were determined fluorometricallyin vivousing a Kr+‐laser (wavelength = 406.7 nm) and a mercury arc lamp (wavelength = 405 or 550 nm) for fluorescence excitation of Photofrin II. Fluorescence was detected at the maxima of the emission bands, at 630 or 690 nm. The results of the experiments show that Photofrin II can be clearly detected by its fluorescence in all the organs investigated from 3 h up to at least 28 days after systemic application of the substance. Within this investigational period the fluorescing components of Photofrin II are released continuously from the organs. In all the tissues examined, an initial decrease with time constants between 2 and 42 h followed by a slow decay with time constants between about 300 and 600 h can be observed.

In addition the pharmacokinetics of the fluorescent components of Photofrin II in chemically induced rat bladder tumors with different stages of malignancy were compared to healthy rat bladder tissue. In a time range of 2–10 days after intraveneous injection Photofrin II shows a fluorescence 2–5 times brighter in rat bladder tumors than in healthy bladder tissue.
SHORT‐TERM ADAPTATION OF HIGHER PLANTS TO CHANGING LIGHT INTENSITIES AND EVIDENCE FOR THE INVOLVEMENT OF PHOSPHORYLATION OF THE LIGHT HARVESTING CHLOROPHYLLalbPROTEIN COMPLEX OF PHOTOSYSTEM II
Authors: Dau Holger , Canaani Ora
Published: January 2008

Abstract—The short‐term adaptation of intact leaves to an increase in light intensity was studied by an analysis of chlorophyll fluorescence and oxygen evolution monitored by photoacoustics. An increase in light intensity led to an oxygen “gush”. This “gush” was followed by a large (up to 120%) biphasic increase in the yield of oxygen evolution characterized by a fast phase (T = 0.5–2 min) and a slow phase (T = 4–20 min). The fast phase of the increase in oxygen yield was coupled to a decrease of fluorescence, whereas the slow phase was accompanied by a parallel fluorescence increase. A comparison of fluorescence parameters with oxygen yield indicates that the slow phase of the increase in oxygen yield was coupled to an increase in the antenna size of photosystem II. The slow phase was not inhibited by the uncoupler Nigericin but it was absent in chlorophyll‐b‐less barley mutants deñcient in the light harvesting chlorophylla/bprotein complex of photosystem II (LHC II). These experiments indicate that changes in the LHC II mediated energy distribution, which occur in the time‐range of several minutes, are involved in the adaptation to changing light intensities. Moreover, electrophoretic analysis of32P orthophosphate labeled leaf discs adapted to low and high light intensities suggests that the slow phase of the increase in oxygen evolution involves dephosphorylation of the 25 kDa polypeptide of LHC II, by a small extent of 12%. The trigger for the slow phase of the increase in oxygen yield does not involve the oxidation of the plastoquinone pool. It was found that in response to the increased light intensity, the plastoquinone pool became more reduced as judged by model calculations. Experiments with the uncoupler Nigericin suggest that the control of the slow phase of adaptation to increased light intensity was also not exerted by the pH gradient across the thylakoid membrane.

The similarities between the adaptation to increased light intensity and the state II to state I transition suggest that both adaptation phenomena involve LHC II dephosphorylation possibly triggered by the cytochromeb6/fcomplex.
LIPOPROTEIN‐MEDIATED DISTRIBUTION OF N‐ASPARTYL CHLORIN‐E6 IN THE MOUSE
Authors: Kessel David , Whitcomb K. Lane , Schulz Veronique
Published: January 2008

Abstract— The localization of many photosensitizing agents has been attributed to distribution of low density lipoprotein (LDL)‐bound drug as a function of the relative numbers of LDL receptors in different tissues. While the chlorin derivative NPe6 is a potent photosensitizing agent in the mouse, it binds mainly to mouse plasma high density lipoproteins (HDL) and albumin, with only 1% bound to LDL. This pattern suggests only a minor role for the LDL‐receptor pathway with regard to N‐aspartyl chlorin e6 (NPe6) biodistribution. Moreover, patterns of accumulation of radioactive NPe6, LDL and HDL in murine tissues are consistent with the suggestion that distribution of NPe6 to different tissues cannot be explained on the basis of an LDL‐mediated mechanism.
CONFORMATIONAL CHANGES OF CYTOSOLIC LOOPS OF BOVINE RHODOPSIN DURING THE TRANSITION TO METARHODOPSIN‐II: AN INVESTIGATION BY FOURIER TRANSFORM INFRARED DIFFERENCE SPECTROSCOPY*
Authors: Ganter Ulrich M. , Charitopoulos Triantaphyllia , Virmaux Noelle , Siebert Friedrich
Published: January 2008

Abstract—In order to assign the structural changes of the protein, observed in the Fourier transform infrared (IT‐IR) difference spectra of the rhodopsin‐metarhodopsin‐II transition, to specific regions of the protein, rhodopsin was treated by proteases. Nonilluminated and bleached rhodopsin was treated with protease K and papain. Rhodopsin digested in the bleached state was subsequently regenerated with 11 ‐cis‐retinal. From these modified samples the rhodopsin‐metarhodopsin‐II FT‐IR difference spectra were measured. Comparing the difference spectra with that of unmodified rhodopsin, clear deviations in the amide‐I and amide‐II spectral range are observed. This indicates that in the unmodified pigment conformational changes of those parts of the cytosolic surface take place which are susceptible to the proteases. From the larger spectral changes obtained with samples digested in the bleached state it is concluded that the extent of modification is larger. The difference spectra of rhodopsin modified with 10 mM dithiothreitol support the existence of the 4th loop which also undergoes conformational changes. The spectral changes are interpreted in terms of a transition of an ordered structure of the loops in rhodopsin to a more random structure in metarhodopsin‐II. The results demonstrate that by combining FT‐IR spectroscopy with protein modification by specific proteases, conformational changes of the protein can be localized to specific regions.
SIMULATIONS OF Prosthecochloris BACTERIOCHLOROPHYLL a‐PROTEIN OPTICAL SPECTRA IMPROVED BY PARAMETRIC COMPUTER SEARCH
Authors: Lu Xiaoyuan , Pearlstein Robert M.
Published: January 2008

Recently, reasonable spectral simulations of the experimental low‐temperature absorption and circular dichroism (CD) spectra of the bacteriochlorophyll (BChl) a protein from Prosthecochloris aestuarii were produced for the unaggregated protein trimer based on standard assumptions regarding QY transition moment directions. We report here significant improvements of these simulations, obtained by computer search of unknown parameters including the site wavelengths of the individual BChl and exciton‐transition line widths. Absorption and CD spectra are fit with a common set of search parameter values. As before, calculated exciton‐transition wavelengths and line widths also compare favorably with values deduced from laser hole‐burning experiments. However, the improved simulations are only obtained when comparison is made to 77 K data obtained with a cryosolvent containing glycerol but not glycerophosphate. Simulations of 77 K data obtained with a mixture of glycerol and glycerophosphate are poorer than those recently reported. (The latter are based on 5 K absorption and 77 K CD data, with transition line widths independently selected for each simulation.) Computer tests of the search routine demonstrate that these results are independent of the routine itself. A possible explanation is that the glycerophosphate‐containing cryosolvent perturbs the protein structure enough to alter slightly the inter‐BChl geometry.
ANOTHER ROLE OF CHLOROPHYLL a/b BINDING PROTEINS OF HIGHER PLANTS: THEY MODULATE PROTOLYTIC REACTIONS ASSOCIATED WITH PHOTOSYSTEM II
Authors: Jahns Peter , Junge Wolfgang
Published: January 2008

Chlorophyllalbbinding proteins serve as light‐harvesting antennae. Additionally they seem to modulate proton pumping by photosystem II, because their covalent modification byN, N‐dicyclohexylcarbodiimide is paralleled by a short‐circuit of this activity. This side action was further characterized in comparative study with control thylakoids and thylakoids lacking chlorophyllalbbinding proteins. The latter were derived from peas grown under intermittent light. They differed from controls in the following: (i) after incubation with A^A^‐dicyclohexylcarbodiimide there was no protonic short circuit, (ii) under flashing light the rate of proton consumption at the acceptor side of photosystem II was accelerated and (iii) the periodical pattern of proton release from water oxidation was flattened out. It was obvious that chlorophyllalbbinding proteins modulated the kinetics and the stoichiometry of proton release from water oxidation and proton uptake at the quinone binding pocket.
NONLINEAR LASERSPECTROSCOPIC INVESTIGATIONS OF THE PIGMENT‐PIGMENT INTERACTION WITHIN THE LIGHT‐HARVESTING COMPLEX OF PHOTOSYSTEM II
Authors: Bittner T. H. , Voigt J. , Irrgang K.‐D. , Renger G.
Published: January 2008

Using a pump and test beam technique in the frequency domain with pump pulses in the nanosecond time range, the nonlinear transmission properties were investigated at room temperature in photosystem (PS) II membrane fragments and isolated light‐harvesting chlorophylla/b‐protein preparations (LHC II preparations). In LHC II preparations and PS II membrane fragments, respectively, pump pulses of 620 nm and 647 nm cause a transmission decrease limited to a wavelength region in the nearest vicinity of the pump pulse wavelength (full width at half maximum ' 0.24 nm). In contrast, at 670 nm neither a transmission decrease nor a narrow band feature were observed. The data obtained for PS II membrane fragments and LHC II preparations at shorter wavelengths (620 nm, 647 nm) were interpreted in terms of excited state absorption of whole pigment‐protein clusters within the light‐harvesting antenna of photosystem II. The interpretation of the small transmission changes as homogeneously broadened lines led to a transversal relaxation time for chlorophyll in the clusters of about 4 ps.
ATTEMPTED BIOSTIMULATION OF DIVISION IN Saccharomyces cerevisiae USING RED COHERENT LIGHT
Authors: Quickenden T. I. , Danniels L. L.
Published: January 2008

Replicate cultures of the yeast, Saccharomyces cerevisiae were irradiated with 632.8 nm coherent light from He‐Ne lasers at irradiances of 6.5 times 1015 and 1.0 times 1016 photons s−1 cm−2. Irradiation periods ranged from 0 to 652 min, and cultures were grown until well into the exponential phase. Unirradiated control cultures were grown alongside the irradiated cultures under otherwise identical conditions. The extents of growth in the control and irradiated cultures were compared spectrophotometrically at the end of each experiment. contrary to the expectations of Karu et al. (e.g. Karu, 1988, Lasers Life Sci.2, 53–74) no growth enhancement was found in the irradiated cultures, but a mild inhibitory effect was observed.
LIGHT‐MEDIATED ACTIVITIES OF THIARUBRINES AGAINST HUMAN IMMUNODEFICIENCY VIRUS
Authors: Hudson J. B. , Balza F. , Harris L. , Towers G. H. N.
Published: January 2008

Abstract— Two thiarubrines (dithiacylohexadienes), which werw isolated recently species of Astreraceae, were investigated for light‐mediated antiviral activity aginst human immunodeficiency virus(HIV–1). Both compounds (thiarubrines A and D) showed good anti‐HIV activity, in micromolar concentrations, which was dependent upon UVA radiation, They showed no anti‐viral activity in the darjm ad only weak visiblke light‐mediated activity, despite the significant absorbance of these compounds in th e480 nm region. the resulting inactivated virus was unable to replicate in cell cultures, as indicated by loss of cytopathogenicity, the absence of cells expressingHIV–1 antigens and lack of production ofHIV–1 p24 protein. although this antiviral was not as efficient as that shown by the photoactive plant thiopene, α‐terthienyl, both thiarubrines demonstrated increased activity when the serum component of the virus stock was reduced. This suggested that a component of bovine serum unterfered to some extent with the anti‐HIV ativity.
PHOTOACTIVABLE FLUOROPHORES FOR THE MEASUREMENT OF FLUENCE IN TURBID MEDIA
Authors: Lilge L. , Flotte T. J. , Kochevar I. E. , Jacques S. L. , Hillenkamp F.
Published: January 2008

Knowledge of the fluence distribution in biological tissue is essential for applications of lasers and light in medicine. A method using a photoactivable fluorophore as a chemical actinometer is presented to investigate the fluence (J/cm2) distribution in tissue‐simulating phantoms. Such a chemical actinometer provides high spatial resolution (≤20 μm) while minimizing the disturbance of the fluence distribution. The actinometer substance, nonfluorescent in its native state, is incorporated into an acrylamide gel. Upon absorption of 351 nm radiation (λact), the actinometer substance becomes a Ruorophorc, which is excited at λex≤ 485 nm. Thus the spatial distribution of the emitted fluorescence (λem≤ 515 nm) in the actinometer represents the fluence distribution of the activating radiation. Using histological techniques, 20 μm sections are cut from gel‐like optical phantoms containing the actinometric substance. The fluorescence intensity in the section is recorded under a standard fluorescence microscope equipped with a sensitive video camera. To simulate different biological tissues, the scattering and absorption properties of the gel phantoms arc varicd over a wide range. The experimentally obtained fluence distributions are compared with theoretical models of light distribution in turbid media.
PHOTOLESIONS IN DNA UPON 193 nm EXCITATION
Authors: Gurzadyan Gagik G. , Görner Helmut
Published: January 2008

Aqueous solutions of plasmid (pBR322 and pTZ18R) and calf thymus DNA were excited by 20 ns laser pulses at 193 nm. The quantum yields of single‐ and double‐strand break formation, interstrand cross‐links, locally denatured sites, (6–4)photoproducts and biological inactivation (Φssb, Φdsb, Φicl, Φids, Φ6–4and Φina, respectively) were measured. The quantum yields are virtually independent of intensity, demonstrating a one‐quantum process. The obtained values in aerated neutral solution in the absence of additives are Φssb= 1.5 × 10‐‐3, Φdsb, = 0.06 × 10‐‐3(dose: 10–200 J m‐2), Φicl=ΦIds= 0.1 × 103and Φ6–4= 0.5 × 10‐‐3Both Φssband Φdsbdecrease strongly with increasing concentrations of TE buffer (0.01–10 mM). Biological inactivation of the pTZ18R plasmid was determined from the transformation efficiency ofEscherichia colibacteria strains AB1157, AB1886 uvr and A82480 uvr rec; the Φinavalues are 1.4 × 103, 2.1 × 103and 3 × 10‐‐3, respectively. The monoexponential survival curves in all cases show that a single damage site leads to inactivation (one single hit). The biological consequences of different photoproducts are discussed.
In viva PHOTODYNAMIC EFFECTS OF PHTHALOCYANINES IN A SKIN‐FOLD OBSERVATION CHAMBER MODEL: ROLE OF CENTRAL METAL ION AND DEGREE OF SULFONATION
Authors: Leengoed H. L. L. M. Van , Veen N. van der , Versteeg A. A. C. , Ouellet R. , Lier J. E. van , Star W. M.
Published: January 2008

Six sulfonated metallophthalocyanines, chelated with either aluminum or zinc and sulfonated to different degrees, were studied in vivo for their photodynamic activity in a rat skin‐fold chamber model. The chamber, located on the back of female WAG/Rij rats, contained a syngeneic mammary carcinoma implanted into a layer of subcutaneous tissue. Twenty‐four hours after intravenous administration of 2.5 μmol/kg of one of the dyes, the chambers received a treatment light dose of 600 J/cm2 with monochromatic light of 675 nm at a power density of 100 mW/ cm2. During light delivery and up to a period of 7 days after treatment, vascular effects of tumor and normal tissue were scored. Tumor cell viability was determined by histology and by reimplantation of the chamber contents into the skin of the same animal, either 2 h after treatment or after the 7 day observation period. Vascular effects of both tumor and subcutaneous tissue were strongest with dyes with the lowest degree of sulfonation and decreased with increasing degree of sulfonation. Tumor regrowth did not occur with aluminum phthalocyanine mono‐ and disulfonate and with zinc phthalocyanine monosulfonate. With the protocol that was used, complete necrosis without recovery was only observed when reimplantation took place at the end of the 7 day follow‐up period. Reimplantation 2 h after treatment always resulted in tumor regrowth. At this interval, the presence of viable tumor cells was confirmed histologically. In general tumor tissue vasculature was more susceptible to photodynamic damage than vasculature of the normal tissue. The effect on the circulation of both tumor and normal tissue increased with decreasing degree of sulfonation. Based on this study, the photodynamic effects using the six sulfonated metallophthalocyanines on the vasculature can be ranked from high to low as: AlPcS2= ZnPcS1 > AIPcS1 > AIPcS4 > ZnPcS2 > ZnPcS4.
SPECTROSCOPIC STUDY OF CHLOROPHYLLaIN ORGANIC SOLVENTS AND POLYMERIZED ANHYDROUS POLYVINYL MATRIX
Authors: Zandvoort Marc A. M. J. van , Wroabel Danuta , Scholten Andries J. , Jager Dries de , Ginkel Glis van , Levine Yehudi K.
Published: January 2008

In this paper we present a spectroscopic study of chlorophyllain solutions and in anhydrous polyvinyl alcohol films. Absorption, excitation and emission spectra, combined with fluorescence lifetime and time‐resolved anisotropy measurements show that chlorophyllain anhydrous polyvinyl alcohol films exists in a purely monomeric state. Furthermore, it appears that the monomeric chlorophyllaexhibits an efficient excitation energy transfer in this polyvinyl alcohol matrix. These results are rationalized in terms of a model in which the chlorophyllamolecules are located within pockets, formed by the polymer chains. It is concluded that the chlorophyll a‐anhydrous polyvinyl alcohol film is a suitable system for studying energy transfer processes, especially because the factors governing energy transfer such as mutual orientation and separation of the molecules can easily be controlled.
HEAT‐ AND LIGHT‐INDUCED CHLOROPHYLL a FLUORESCENCE CHANGES IN POTATO LEAVES CONTAINING HIGH OR LOW LEVELS OF THE CAROTENOID ZEAXANTHIN: INDICATIONS OF A REGULATORY EFFECT OF ZEAXANTHIN ON THYLAKOID MEMBRANE FLUIDITY
Authors: Havaux Michel , Gruszecki Wieslaw I.
Published: January 2008

Potato leaf discs were infiltrated in darkness with a buffer of pH 5 containing 100 M ascorbate, resulting in a massive conversion of the carotenoid violaxanthin to zeaxanthin. In vivo measurements of modulated chlorophyll a fluorescence indicated that this treatment (1) caused a marked upward shift of the threshold temperature at which photosystem II denatures and (2) noticeably inhibited the rate of dark reoxidation of the reduced plastoquinone (at low temperature). These changes were not induced in leaves infiltrated with a buffer of pH 5 containing no ascorbate or with 100 mM ascorbate at pH >7.2. The above‐mentioned effects were also observed during heat acclimation (34°C for several days) of potato plants and suggested that zeaxanthin interacts with the lipid phase of the thylakoid membranes. Based on those results and the previous data obtained with model systems, it is suggested that the xanthophyll cycle could be a regulatory mechanism adjusting thylakoid membrane fluidity, the significance of which for the photoprotection of the photosynthetic apparatus is discussed.
NON‐NUCLEAR DAMAGE AND CELL LYSIS ARE INDUCED BY UVA, BUT NOT UVB OR UVC, RADIATION IN THREE STRAINS OF L5178Y CELLS
Authors: Beer Janusz Z. , Olvey Kathleen M. , Miller Sharon A. , Thomas Delma P. , Godar Dianne E.
Published: January 2008

The 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 monitored in vitro using 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/m2 for the UVASUN lamp, 75 to 390 J/m2 for the FS20 lamp and 3.8 to 17.2 J/m2 for 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 LY cells.
THE TREATMENT OF MASTOCYTOMA CELLS WITH 8‐METHOXYPSORALEN AND LONG‐WAVELENGTH ULTRAVIOLET RADIATION ENHANCES CELLULAR IMMUNOGENICITY: PRELIMINARY RESULTS
Authors: Gasparro Francis P. , Malane Michelle S. , Maxwell Virginia M. , Tigelaar Robert E.
Published: January 2008

Evidence 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 treatment of cutaneous T cell lymphoma.
PROTECTION AGAINST ULTRAVIOLET B RADIATION‐INDUCED EFFECTS IN THE SKIN OF SKH‐1 HAIRLESS MICE BY A POLYPHENOLIC FRACTION ISOLATED FROM GREEN TEA
Authors: Agarwal Rajesh , Katiyar Santosh K. , Khan Sikandar G. , Mukhtar Hasan
Published: January 2008

In prior studies we and others have shown that oral feeding of a polyphenolic fraction isolated from green tea (GTP) or water extract of green tea affords protection against ultraviolet B (UVB) radiation‐induced carcinogenesis in SKH‐1 hairless mice (Wang et al., Carcinogenesis 12, 1527–1530, 1991). It is known that exposure of murine skin to UVB radiation results in cutaneous edema, depletion of the antioxidant‐defense system and induction of ornithine decarboxylase (ODC) and cyclooxygenase activities. In this study we assessed the protective effect of GTP on these UVB radiation‐caused changes in murine skin. Oral feeding of 0.2% GTP (wt/vol) as the sole source of drinking water for 30 days to SKH‐1 hairless mice followed by irradiation with UVB (900 mJ/cm2) resulted in significant protection against UVB radiation‐caused cutaneous edema (P <0.0005) and depletion of the antioxidant‐defense system in epidermis (P <0.01–0.02). The oral feeding of GTP also resulted in significant protection against UVB radiation‐caused induction of epidermal ODC (P <0.005–0.01) and cyclooxygenase activities (P <0.0001) in a time‐dependent manner. Our data indicate that the inhibition of UVB radiation‐caused changes in these markers of tumor promotion in murine skin by GTP may be one of the possible mechanisms of chemopreventive effects associated with green tea against UVB‐induced tumorigenesis. The results of this study suggest that green tea, specifically polyphenols present therein, may be useful against inflammatory responses associated with the exposure of skin to solar radiation.
COLLAGEN ALTERATIONS IN CHRONICALLY SUN‐DAMAGED HUMAN SKIN
Authors: Schwartz Elaine , Cruickshank Frederick A. , Christensen Carolyn C. , Perlish Jerome S. , Lebwohl Mark
Published: January 2008

Abstract The major histological characteristic of sun‐damaged skin is the accumulation of an elastotic material that appears to replace collagen. This elastotic material consists primarily of elastin and histological studies suggest a large loss of collagen in the dermis of chronically sun‐damaged skin. In this study, we examine the content and distribution of collagen and procollagen in sun‐damaged human skin. The total collagen content of sun‐damaged skin was 20% less than nonsolar‐exposed skin (524 μg collagen per mg total protein in sun‐damaged skin and 667 μg collagen per mg total protein in nonsolar‐exposed skin). In addition, there was a 40% decrease in the content of intact amino propeptide moiety of type III procollagen in sun‐damaged skin (0.68 U per 50 mg wet weight) as compared to nonsolar‐exposed skin (1.12 U per 50 mg wet weight). The data suggest that this change in collagen content is due to increased degradation. The distribution of collagen in sun‐damaged skin was examined by indirect immunofluo‐rescence. Mild digestion of sun‐damaged skin with elastase removed the elastin and revealed the presence of collagen in the elastotic material. Therefore, the elastin appears to mask the presence of collagen fibers in the dermis of sun‐damaged skin.
INTRACELLULAR TARGET FOR α‐TERTHIENYL PHOTOSENSITIZATION: INVOLVEMENT OF LYSOSOMAL MEMBRANE DAMAGE
Authors: Sasaki Masako , Koyama Sumihiro , Tokiwa Kiminori , Fujita Hitoshi
Published: January 2008

Abstract—Intracellular targets for the photosensitizer α‐terthienyl (αT) were examined by fluorescence microscopy and microfluorospectrometry using human nonkeratinized buccal cells. Intracellular distribution of αT was observed as fluorescent patches widely dispersed in the cytoplasm. The distribution of the fluorescent patches was compared with that of acid phosphatase activity visualized as an azo dye produced by the fast garnet 2‐methyl‐4‐[(2‐methyl‐phenyl)azo]benzenediasonium sulfate reaction. Because both the distribution sites coincided, lysosomes were the likely sites of intracellular affinity of αT. However, because acid phosphatase is not a specific lysosomal marker, we tried to detect another lysosomal enzyme, β‐galactosidase, to confirm if the fluorescent patches were lysosomes, using fluorescein‐di‐(β‐D‐galactopyranoside) (FDG) as a fluorogenic substrate. Without UV‐A (320–400 nm) irradiation of the cells after uptake of αT and FDG, no significant fluorescence was observed. In contrast, with prior UV‐A irradiation in the presence of αT and FDG, the bright yellow fluorescence of fluorescein, which is the digested product of FDG, was clearly detected in the cells by fluorescence microscopy. This observation implied that inflow of external FDG into the lysosomes is caused by lysosomal membrane damage on αT photosensitization. The present results indicated that lysosomes are the primary photosensitization site of αT.
POLARIZED SPECTRA OF ORIENTED PIGMENT‐LIPOPROTEIN COMPLEXES FROM THE PURPLE BACTERIUM: Chromatium minutissimum
Authors: Frackowiak Danuta , Abdourakhmanov Ismail , Cegielski Roman , Leblanc Roger M.
Published: January 2008

Abstract— Polarized absorption, fluorescence and photoacoustic spectra of bacteriochlorophyll (BChl)‐lipoprotein complexes from the purple bacterium Chromatium minutissimum oriented in stretched polyvinylalcohol films were measured at room temperature and 85 K. The preparations contain large amounts of the B800‐820 antenna complexes. From polarized absorption spectra taken under various light beam incidence angles with respect to the film plane, conclusions concerning arrangement of pigment molecules in B800‐820 complex are obtained. The transition moments of the BChl Qy band are not exactly parallel to the membrane plane. It seems that there are pools of differently oriented BChl chromophores absorbing in both 800 nm and 820 nm regions. Change in temperature strongly influences linear dichroism of carotenoids and BChl Qy bands. The reversible changes in absorption, linear dichroism and photoacoustic spectra caused by the variation in sample temperature suggest strongly the reversible twisting of carotenoid molecules, related probably to modification of the interactions between carotenoids and proteins. Various carotenoids exhibit different yield of thermal deactivation and this yield is also temperature dependent.
CALCIUM‐DEPENDENT FLUORESCENCE LIFETIMES OF INDO‐1 FOR ONE‐ AND TWO‐PHOTON EXCITATION OF FLUORESCENCE
Authors: Szmacinski Henkyk , Gryczynski Ignacy , Lakowicz Joseph R.
Published: January 2008

Abstract— We characterized the fluorescence intensity decays of Indo‐1, which is commonly used as an emission wavelength‐ratiometric calcium probe. The apparent lifetime of the long‐wavelength side of the emission of Indo‐1 is dependent on Ca2+. This long‐wavelength emission displays the characteristics of an excited‐state reaction, that is, a negative preexponential component in thc multiexponential analysis. The emission spectra and lifetime of Indo‐1 appear to be identical for one‐photon and two‐photon excitation at 351 and 702 mn, respectively, suggesting that the relative one‐ and two‐photon cross sections are similar for the calcium‐free and calcium‐bound forms of Indo‐1. Also, the two‐photon cross section of Indo‐1 is relatively high, about 4 × 10−49 cm4 s/photon molecule at 690 nm for both the calcium‐free and calcium‐bound forms. Hence, Indo‐1 can be used for calcium imaging based on one‐ or two‐photon excitation, using either emission wavelength ratios or lifetime imaging methods.
PHOTOBLEACHING OF MONO‐l‐ASPARTYL CHLORIN e6 (NPe6): A CANDIDATE SENSITIZER FOR THE PHOTODYNAMIC THERAPY OF TUMORS
Authors: Spikes John D. , Bommer Jerry C.
Published: January 2008

Abstract— Most sensitizers used for the photodynamic therapy (PDT) of tumors photobleach on illumination. Thus, it is of interest to examine the photobleaching behavior of new sensitizers proposed for use in PDT. This report surveys the quantum yields and kinetics of the photobleaching of mono‐l‐aspartyl chlorin e6 (NPe6), a hydrophilic chlorin that has many of the photoproperties desirable in a sensitizer for clinical PDT. It is a very effective sensitizer for the PDT of several types of model tumors in animals and is now in Phase I clinical trials. The quantum yield of NPe6 photobleaching in pH 7.4 phosphate buffer in air was 8.2 × 10−4; this is greater than the yields for typical porphyrin photosensitizers. For example, the yields for hematoporphyrin and uroporphyrin are 4.7 × 10 5 and 2.8 × 10−5, respectively. The yield decreased significantly in organic solvents of low dielectric constant. The Sn derivative of NPe6 was more light stable than NPe6 (yield = 5.7 × 10 −6), while the Zn derivative was more sensitive (yield = 1.9 × 10−2). Oxygen appeared to be necessary for the photobleaching of NPe6; however, bleaching was not inhibited by 100 mM azide, an efficient quencher of singlet oxygen. The photooxidizable substrates cysteine, dithiothreitol and furfuryl alcohol increased the quantum yield of photoblcaching two‐ to four‐fold, while the electron acceptor, met‐ronidazole, increased it almost six‐fold. Photobleaching yields for several other chlorins were also measured.
A NEW PHOTOPRODUCT FROM FUROCOUMARIN PHOTOLYSIS IN DILUTE AQUEOUS SOLUTION: 5‐FORMYL‐6‐HYDROXYBENZOFURAN
Authors: Marley Karen A. , Larson Richard A.
Published: January 2008

Abstract—This paper presents the analysis and identification of an unstable product previously undescribed from furocoumarin photolysis, 5‐formyl‐6‐hydroxybenzofuran. Reverse‐phase chromatography and solid‐phase extraction techniques allowed its isolation.
LASER PHOTOSENSITIZATION OF CELLS BY HYPERICIN
Authors: Andreoni A. , Colasanti A. , Colasanti P. , Mastrocinque M. , Riccio P. , Roberti G.
Published: January 2008

Abstract— Administering a light dose of 90 J/cm2 at 599 nm during incubation with hypericin to a highly differentiated normal epithelial cell line(FRTL–5), derived from Fisher rat thyroid, and to a neoplastic cell line(MPTK–6), derived from the lung metastases of a thyroid carcinoma induced in Fisher rats, produces cell kill at drug doses 1000 times lower than those necessary to cause the same mortality in the dark. The photocytocidal activity of this polycyclic quinone drug on neoplastic cells is superior to that of antitumor anthraquinone drugs, such as daunomycin and mitoxanthrone, and to the photosensitized antiviral activity previously reported for hypericin.
EARLY ALTERATIONS OF ACTIN IN CULTURED HUMAN KERATINOCYTES AND FIBROBLASTS EXPOSED TO LONG‐WAVELENGTH RADIATIONS. POSSIBLE INVOLVEMENT IN THE UVA‐INDUCED PERTURBATIONS OF ENDOCYTOTIC PROCESSES
Authors: Djavaheri‐Mergny M. , Pieraggi M. T. , Mazière C. , Santus R. , Lageron A. , Salvayre R. , Dubertret L. , Mazière J. C.
Published: January 2008

Abstract Exposure of cultured MRC5 human fibroblasts or NCTC 2544 human keratinocytes to mild doses of ultraviolet A (UVA: 320‐400 nm) radiations markedly decreased the actin reactivity with fluorescein‐labeled phalloidin. This indicates a change in the degree of poly merization of actin and thus in the organization of actin filaments. Such a phenomenon might be involved in the previously reported UVA‐induced inhibition of specific and nonspecific endocytotic processes.
INVESTIGATION OF THE ALLOMERIZATION REACTION OF CHLOROPHYLL a: USE OF DIODE ARRAY HPLC, MASS SPECTROMETRY AND CHEMOMETRIC FACTOR ANALYSIS FOR THE DETECTION OF EARLY PRODUCTS
Authors: Brereton Richard G. , Rahmani Ali , Liang Yi‐zeng , Kvalheim Olav M.
Published: January 2008

Abstract –The products of chlorophyll allomerization in methanol were isolated and analyzed by open column sucrose chromatography, liquid chromatography mass spectrometry (LCMS) and DAD‐HPLC (diode‐array high‐performance liquid chromatography). Four main bands were found with molecular ions of (a) 908, (b) 938, (c) 938 and (d) 938, consistent with the structures (a) 132‐hydroxy‐chlorophyll a (II), (b) and (c) Mg(II)‐31,32‐didehydro‐151‐hydroxy‐151‐methoxy‐rhodochlorin‐15 acetic acid δ‐lactone 152‐methyl 173‐phytyl ester and its epimer (III) and (d) Mg(II)‐31,32‐didehydro‐rhodochlorin‐15‐glyoxylic acid 131,152‐dimethyl 173‐phytyl ester (IV), evidence enhanced by UV/visible spectroscopy, chromatographic coelutions and chemometrics. Chlorophyll a was degraded both in the dark and light, under O2 and N2. DAD‐HPLC of the resultant degradation mixtures were analyzed using the chemometric heuristic‐evolving latent projection method for resolution. Ultraviolet/visible spectra of II and III are reproducibly extracted from the mixtures after a short degradation time, whereas III and IV are the dominant compounds after longer degradation times. Changes in relative elution order of IV using open column chromatography and reverse‐phase HPLC are established. A possible allomerization pathway is proposed.
SOLVENT EFFECT ON SPHEROIDENE IN NONPOLAR AND POLAR SOLUTIONS AND THE ENVIRONMENT OF SPHEROIDENE IN THE LIGHT‐HARVESTING COMPLEXES OFRhodobacter sphaeroides2.4.1 AS REVEALED BY THE ENERGY OF THE1Ag−→1Bu+ABSORPTION AND THE FREQUENCIES OF THE VIBRONICALLY COUPLED C=C STRETCHING RAMAN LINES IN THE1Ag−AND1Bu−STATES
Authors: Kuici Michitaka , Nagae Hiroyoshi , Cogdell Richard J. , Shimada Keizo , Koyama Yasushi
Published: January 2008

Abstract–The1Ag−→1Bu+electronic absorption band and the vibronically coupled, C=C stretching Raman lines in the1Ag−and 21Ag−states were recorded for spheroidene free in nonpolar and polar solvents as well as for spheroidene bound to the LH1 and LH2 complexes ofRhodobacter sphaeroides2.4.1. The1Bu+energy exhibited a linear dependence on R(n) = (n2‐ 1)/(n2+ 2) in both nonpolar and polar solvents; the line for polar solvents had a gentler slope and crossed the line for nonpolar solvents at R(n) = 0.3. The above characteristic of polar solvents was ascribed to the electric field generated by fluctuation of the solvent permanent dipoles; it stabilizes the1Bu+energy and reduces the polarizability of the solvent. The vibronically coupled, C=C stretching frequencies in the1Ag−and 21Ag−states [ν(Ag) and [ν(2Ag)] also showed similar dependence on R(n), which is explained in terms of vibronic coupling among the1Ag−, 21Ag−and 31Ag−states.

The environment of spheroidene in the LH2 and LH1 complexes was assessed on the basis of the1Bu+energy and the ν(Ag) and [ν(2Ag) frequencies: Spheroidene in the LH2 complex is located in an environment with high polarizability, while spheroidene in the LH1 complex is located in an environment with lower polarizability.
CONTINUOUS, NONINVASIVE MEASUREMENT OF In Vivo pH IN CONSCIOUS MICE
Authors: Russell David A. , Pottier Roy H. , Valenzeno Dennis P.
Published: January 2008

Extracellular pH was measured continuously and noninvasively in hairless mice using a transcutaneous spectronuorometric technique and a fluorescent pH probe, bis‐carboxyethyl carboxyfluorescein (BCECF). The acid form of BCECF was injected intravenously. An optical fiber system excited the florescent probe at 450 and 500 nm alternately, using one branch of a bifurcated, fiber optic bundle. The other branch of the bundle collected the emitted fluorescence which was measured by a photomultiplier tube. The ratio of fluorescence intensities from the two excitation wavelengths was pH dependent. Measurements could be obtained for approximately 60 min following a single injection. Mice exposed to elevated partial pressures of CO2 demonstrated changes in the fluorescence ratio indicative of a dramatic decrease in extracellular pH. If the exposure was brief, the fluorescence signal recovered within 20 min. The fluorescence intensity ratio was calibrated against aqueous BCECF samples in vitro. Fluorescence pH values determined using the in vitro calibration were compared with measurements made on blood samples taken from seven mice. Extracellular pH in hairless mice was found to be approximately 7.5, within the expected physiological range. The variability of the pH signal derived from the fluorescence signal was approximately 0.05 units.
FLUORESCENCE QUANTUM YIELD DETERMINATION OF PYRIMIDINE (6‐4) PYRIMIDONE PHOTOADDUCTS
Authors: Blais J. , Douki T. , Vigny P. , Cadet J.
Published: January 2008

Abstract An extensive study of the fluorescence characteristics of pyrimidine (6‐4) pyrimidone photoadducts, a major class of far‐UV‐induced DNA lesions, was carried out on dinucleoside monophosphate (6‐4) photoadducts, including thymidylyl‐(3’→ 5′)‐thymidine (TpT), 2′‐deoxycytidylyl‐(3′‐5′)‐thymidine, thymidylyl‐(3’→ 5′)‐2′‐deoxy‐cytidine, 2′‐deoxyuridylyl‐(3’→ 5′)‐thymidine, 5‐methyl‐2′‐deoxycytidylyl‐(3′‐5′)‐thymidine (6‐4) photoadducts and the corresponding base (6‐4) photoadducts, 6‐4′‐(5′‐methylpyrimidin‐2′‐one) thymine (TT), 5‐hydroxy‐6‐4′‐(5′‐methylpyrimidin‐2′‐one)‐5,6‐dihydrothymine (CT), 5‐amino‐6‐4′‐(pyrimidin‐2′‐one)‐5,6‐dihydrothymine (UC) obtained by mild acidic hydrolysis of the former derivatives. The fluorescence quantum yield (ΦF) of these compounds was found to depend on one hand, on the nature of the two bases involved and the base substituent and, on the other hand, on the presence of the phosphate group. The hydrolysis of the phosphodiester bond was shown to enhance ΦF, the larger effect being observed in the case of the thymine‐thymine photoadducts with a seven‐fold increase of the ΦF value in the case of TT as compared to TpT (0.21 and 0.03, respectively). These results are discussed in terms of structural considerations.
PHOTOCHEMICAL AND PHOTOBIOLOGICAL PROPERTIES OF KETOPROFEN ASSOCIATED WITH THE BENZOPHENONE CHROMOPHORE
Authors: Boscá Francisco , Miranda Miguel A. , Carganico Germano , Mauleon David
Published: January 2008

Abstract Irradiation of ketoprofen in neutral aqueous medium gave rise to 3‐ethylbenzophenone as the major photoproduct. Its formation is justified via protonation of a benzylic carbanion or hydrogen abstraction by a benzylic radical. Minor amounts of eight additional compounds were isolated. Four of them are derived from the benzylic radical: 3‐(1‐hydroperoxyethyl)benzophenone, 3‐(1‐hydroxyethyl)benzophenone, 3‐acetylbenzophenone and 2,3‐bis‐(3‐benzoylphenyl)butane. The other four products involve initial hydrogen abstraction by the excited benzophenone chromophore of ketoprofen: 1,2‐bis‐(3‐ethylphenyl)‐1,2‐diphenyl‐1,2‐ethanediol, 2‐(3‐benzoylphenyl)‐1‐(3‐ethylphenyl)‐1 ‐phenylpropan‐1 ‐01,α ‐(3‐ethylphenyl)phenylmethanol, 1,2‐bis‐[3‐(2‐hydroxycarbonylethyl)phenyl]‐1,2‐di‐phenyl‐1,2‐ethanediol. The latter process was found to mediate the photoperoxidation of linoleic acid through a type I mechanism, as evidenced by the inhibition produced by the radical scavengers butylated hydroxyanisole and reduced glutathione. The major photoproduct, which contains the benzophenone moiety but lacks the propionic acid side chain, also photosensitized linoleic acid peroxidation. Because lipid peroxidation is indicative of cell membrane lysis, the above findings are highly relevant to explain the photobiological properties of ketoprofen.
AMELIORATION OF UV‐B DAMAGE UNDER HIGH IRRADIANCE. II: ROLE OF BLUE LIGHT PHOTORECEPTORS
Authors: Adamse Paulien , Britz Steven J. , Caldwell Charles R.
Published: January 2008

Abstract Sensitivity of plants to UV‐B radiation (280–315 nm) is often reduced at high background irradiance. Interpretation of plant responses to potential increases in solar UV‐B requires improved understanding of interactions between UV‐B and other environmental parameters. In this study, photosynthetically active radiation (PAR, 400–700 nm) was kept approximately constant (38 mol m‐2 per day) while the daily blue light fluence (BL, 400–500 nm) was varied between 0.23 and 2.68 mol m‐2. Two lines of cucumber (cvs Ashley and Poinsett) with differential sensitivity to UV‐B were compared. At low BL, 3 days of UV‐B treatment (21 kJ m‐2 biologically effective radiation per 10 h per day) caused severe inhibition of growth in a developing leaf in both cultivars. Growth effects were detectable sooner and were accompanied by chlorotic lesions in the sensitive cultivar (cv Poinsett). Supplemental BL progressively reduced symptoms, consistent with an important role for BL photoreceptor(s) in prevention or repair of UV‐B damage. Ultraviolet‐induced increases in UV‐absorbing compounds on an area basis were significant within 24 h of the start of the treatment but were independent of BL fluence over the range tested, suggesting that bulk accumulation of screening pigments did not contribute to BL‐dependent amelioration of UV damage. However, BL did stimulate net increases in extractable UV‐absorbing compounds on a total leaf busis, while high‐performance liquid chromatography analysis indicated that BL and UV‐B acted synergistically to increase specific components. Thus, the data do not necessarily exclude UV‐absorbing compounds from an important role in overall UV‐B protection nor do they rule out some more specific function for these compounds (e.g. antioxidants). Finally, BL effects on UV‐B alteration of leaf growth and accumulation of UV‐absorbing compounds were not saturated under the conditions used here, suggesting that BL may contribute to interactions between UV‐B and natural levels of background irradiance. Caution is urged in the interpretation of data on UV‐B effects obtained under conditions of low BL irradiance.