bluuebunny/crossref_metadata_2025_split huggingface dataset:
Correlation Between Oxygen Consumption and Photobleaching During In Vitro Photodynamic Treatment with ATX‐S10‐Na(II) Using Pulsed Light Excitation: Dependence of Pulse Repetition Rate and Irradiation Time¶
Authors: Kawauchi Satoko , Sato Shunichi , Morimoto Yuji , Kikuchi Makoto 
Published: July 2010

ABSTRACTWe revealed that in ATX‐S10‐Na(II)(13,17‐bis (1‐carboxypropionyl) carbamoylethyl‐8‐etheny‐2‐hydroxy‐3‐hydroxyiminoethylidene‐2,7,12, 18‐tetraethyl porphyrin sodium)‐mediated photodynamic therapy using 667 nm nanosecond‐pulsed light excitation at a peak intensity of 2.0 MW/cm2, photoxicity increased with decreasing pulse repetition rate in the range of 5‐30 Hz for A549 cell cultures. To examine the relation between the reaction mechanism and measured phototoxicity, we carefully measured the kinetics of photochemical oxygen consumption and photobleaching during irradiation of ATX‐S10‐Na(II)‐sensitized A549 monolayer cultures. Measurements of oxygen consumption with a microelectrode, which was performed just above the cells, showed that there was no significant difference between the magnitudes of decrease in oxygen at the three repetition rates at the same cumulative fluence. Loss of ATX‐S10‐Na(II) fluorescence intensity also exhibited little repetition rate dependence when compared at the same cumulative fluence. We investigated the correlation between oxygen consumption and photobleaching during irradiation and obtained “fluorescence‐oxygen diagrams.” The diagrams showed dynamic changes between oxygen‐dependent and oxygen‐independent photobleaching at the higher repetition rates of 10 and 30 Hz, whereas such change was not clearly seen over the whole irradiation time at 5 Hz. These results suggest that the reduced phototoxicity at high repetition rates might be due to an oxygen‐independent reaction. We presumed that the change in the reaction mechanism was associated with the local concentrations of the photosensitizer and oxygen in cells during irradiation.
Plant Responses to Current Solar Ultraviolet‐B Radiation and to Supplemented Solar Ultraviolet‐B Radiation Simulating Ozone Depletion: An Experimental Comparison¶
Authors: Rousseaux M. Cecilia , Flint Stephan D. , Searles Peter S. , Caldwell Martyn M. 
Published: July 2010

ABSTRACTField experiments assessing UV‐B effects on plants have been conducted using two contrasting techniques: supplementation of solar UV‐B with radiation from fluorescent UV lamps and the exclusion of solar UV‐B with filters. We compared these two approaches by growing lettuce and oat simultaneously under three conditions: UV‐B exclusion, near‐ambient UV‐B (control) and UV‐B supplementation (simulating a 30% ozone depletion). This permitted computation of “solar UV‐B” and “supplemental UV‐B” effects. Microclimate and photosynthetically active radiation were the same under the two treatments and the control. Excluding UV‐B changed total UV‐B radiation more than did supplementing UV‐B, but the UV‐B supplementation contained more “biologically effective” shortwave radiation. For oat, solar UV‐B had a greater effect than supplemental UV‐B on main shoot leaf area and main shoot mass, but supplemental UV‐B had a greater effect on leaf and tiller number and UV‐B‐absorbing compounds. For lettuce, growth and stomatal density generally responded similarly to both solar UV‐B and supplemented UV‐B radiation, but UV‐absorbing compounds responded more to supplemental UV‐B, as in oat. Because of the marked spectral differences between the techniques, experiments using UV‐B exclusion are most suited to assessing effects of present‐day UV‐B radiation, whereas UV‐B supplementation experiments are most appropriate for addressing the ozone depletion issue.
Comparison of Nonmetal and Metal Hydrophilic Photosensitizer, ATX‐S10 (Na) and ATN‐2, Binding with Human Serum Proteins Using Spectrophotometry¶
Authors: Yamaguchi M. , Tanabe S. , Nakajima S. , Takemura T. , Ogita K. , Kuwayama H. , Sakata I. , Miyaki S. , Suzuki K. , Namiki H. , Uzuka Y. , Sarashina T. 
Published: July 2010

ABSTRACTIntermolecular interactions of human serum proteins with a hydrophilic nonmetalloporphyrin, 13,17‐bis(1‐carboxy‐propionyl)carbomoylethyl‐8‐ethenyl‐2‐hydroxy‐3‐hydroxy‐iminoethylidene‐2,7,12,18‐tetramethylporphyrin sodium salt (ATX‐S10 (Na)), or a hydrophilic gallium‐metalloporphyrin, diethylenetriamine pentaacetic acid ester of 2‐[1‐(2‐hydroxyethoxy)ethyl]‐4‐vinyl‐deuteroporphyrin (IX) Ga complex (ATN‐2), were investigated using spectrophotometry. ATX‐S10 (Na) caused a bathochromic shift with albumin, high‐density lipoprotein and low‐density lipoprotein, but little or no shift was observed with hemopexin, transferrin and immuno‐globulin G. In contrast, ATN‐2 displayed a bathochromic shift only with hemopexin. These results suggest that the association energy of ATX‐S10 (Na) with albumin might be slightly greater than that with lipoproteins and that of ATN‐2 with hemopexin might be greater than that with other serum proteins.
Cellular Uptake and Photocytotoxicity of Glycoconjugated Porphyrins in Hela Cells.¶
Authors: Hirohara Shiho , Obata Makoto , Salto Atsuhiro , Ogata Shin‐ichi , Ohtsuki Chikara , Higashida Suguru , Ogura Shun‐ichiro , Okura Ichiro , Sugal Yuko , Mikata Yuji , Tanihara Masao , Yano Shigenobu 
Published: July 2010

ABSTRACTThirty‐two glycoconjugated porphyrins were synthesized by a modification of Lindsey method in the presence of Zn(OAc)2.2H2O as a template. The Zn2+ ion template strategy improved the yield about three‐fold in the case of meta ‐substituted tetraphenylporphyrins. In addition, free‐base porphyrins were obtained almost quantitatively by demetalation with 4 M HCI. Sixteen deacetylated glycoconjugated porphyrins were tested as candidate photodynamic therapy (PDT) drugs using HeLa cells. Most of the deacetylated glycoconjugated porphyrins showed higher cellular uptake than tetraphenylporphyrin tetrasulfonic acid (TPPS), and 5,10,15, 20‐tetrakis[4‐(β‐D‐arabinopyranosyloxy)phenyl]porphyrin p‐5d) in particular showed 18.5‐fold higher uptake than TPPS. The photocytotoxicity of 5,10,15,20‐tetrakis[4‐(β‐D‐glucopyranosyloxy) phenyl]porphyrin (p‐5a), (p‐5d and TPPS was examined with HeLa cells, using a light dose of 16 J/cm2. These photosensitizers had no cytotoxicity in the dark, but their photocytotoxicity increased in the order of TPPS p‐5a p‐5d. These results suggest p‐5d is a good candidate for a PDT drug.
Photochemical Behavior of a New Long‐chain UV Absorber† Drived from 4‐tert‐Butyl‐4′‐Methoxydibenzoylmethane¶
Authors: Wetz Fabienne , Routaboul Corinne , Lavabre Dominique , Garrigues Jean‐Christophe , Rico‐Lattes Isabelle , Pernet Ingrid , Denis Alain 
Published: July 2010

ABSTRACTA new W filter, the 1‐(4‐tert‐butylphenyl)‐2‐decanyl‐3‐(4′‐methoxyphenyl)‐propane‐1,3‐dione, called C10‐DBM, was prepared by grafting a 10‐carbon aliphatic chain to the acarbonyl position of 4‐tert‐butyl‐4′‐methoxydibenzoylmethane (BM‐DBM), a well‐known and often used UV filter. The UV‐A absorption efficiency of organic solutions containing the new filter was tested and compared with identical solutions containing BM‐DBM with or without irradiation (xenon lamp). The originality of this new filter is that its UV‐A absorbance appeared during irradiation of the molecule. Although the molar absorption coefficient of C10‐DBM in the UV‐A domain was lower than that of BM‐DBM, the solutions absorption exhibited a much more photostable behavior under irradiation. In this study, we first demonstrated that C10‐DBM was a precursor of BM‐DBM (enol isomer) by means of high performance liquid chromatography followed by mass spectrometry. Indeed, we showed that the UV‐A absorption of C10‐DBM solutions appearing during the irradiation of the molecule was due to a Norrish‐II reaction (β‐cleavage), which induced the release of the BM‐DBM enol form and l‐decene. Then, we established a kinetic model for the photochemistry of C10‐DBM and fitted the variation of W absorption spectra to confirm the proposed mechanism.
Removing UV‐A and UV‐C Radiation from UV‐B Fluorescent Lamp Emissions. Differences in the Inhibition of Photosynthesis in the Marine Alga Dunaliella tertiolecta Using Chromate Versus Cellulose Acetate‐Polyester Filters¶
Authors: White Andrea L. , Jahnke Leland S. 
Published: July 2010

ABSTRACTUltraviolet‐B (UV‐B; 280‐320 nm)‐emitting lamps unavoidably emit ultraviolet‐A (UV‐A; 320‐400 nm) and ultraviolet‐C (UV‐C; < 280 nm) radiation. Short‐wavelength‐blocking filters are generally used to limit the wave bands of UV under investigation. The widespread use of such filters means that all exposures to UV‐B radiation will have a significant UV‐A component. Therefore, the physiological effects unique to UV‐B exposure are difficult to clearly isolate. This study presents a method to remove the UV‐A and UV‐C “contamination” using a liquid potassium chromate (K2CrO4) filter, thus allowing more direct assessment of the effects of UV‐B exposure. Cultures of the green marine alga Dunaliella tertiolecta were grown in the absence of UV radiation. Sunlamps supplied the UV radiation for a 24 h exposure (solar radiation was not used in this study). The UV radiation was filtered either by the standard method (i.e. cellulose acetate (CA) with polyester = Mylar controls) or by a liquid filter of potassium chromate. Photosynthetic responses were compared. Major decreases in the ratio of variable to maximal fluorescence in dark‐adapted cells and photosynthetic capacity were observed in CA‐filtered cultures, whereas no change was observed in cells exposed to the same UV‐B flux with the UV‐A removed by K2CrO4. The use of a CA filter with a Mylar control does not link results unequivocally to UV‐B radiation. Such results should be interpreted with caution.
Quantum Dot Nanocrystals for In Vivo Molecular and Cellular Imaging¶
Authors: Smith Andrew M. , Gao Xiaohu , Nie Shuming 
Published: July 2010

AbstractSemiconductor quantum dots (QD) are nanometer‐sized crystals with unique photochemical and photophysical properties that are not available from either isolated molecules or bulk solids. In comparison with organic dyes and fluorescent proteins, QD are emerging as a new class of fluorescent labels with improved brightness, resistance against photobleaching and multicolor fluorescence emission. These properties could improve the sensitivity of biological detection and imaging by at least 10‐to 100‐fold. Further development in high‐quality near‐infrared‐emitting QD should allow ultrasensitive and multicolor imaging of molecular targets in deep tissue and living animals. Here, we discuss recent developments in QD synthesis and bioconjugation, applications in molecular and cellular imaging as well as promising directions for future research.
Behaviors Producing Photodispersal in Stentor coeruleus¶
Authors: Menzies Erin , Das NII , Wood David C. 
Published: July 2010

AbstractThe ciliate Stentor coeruleus exhibits photodispersal, that is, these cells swim away from light sources and collect in dimly lighted areas. We imaged and reconstructed the tracks of 48 Stentor to determine which swimming behaviors produced their photodispersal. We observed that their photodispersal is not due to a change in their swimming speed but rather to a change in the frequency with which they reorient their swimming direction. Therefore, their photodispersal must be due to either (1) a gradual reorientation of the organism's swimming direction determined by the direction of the light beam (phototaxis) or (2) multiple randomly directed reorientations in swimming direction that occur less frequently when the cell is swimming away from the light source (biased random walk). Sixteen (19%) of the 83 observed forward swimming tracks lasting three or more seconds exhibited a gradual bending away from the light source consistent with a phototaxis. However, most tracks were interrupted repeatedly by abrupt reorientations resulting from ciliary reversals and “smooth turns” that caused cells to reorient through 5.4 times as many degrees as were needed to direct them away from the light source. When cells were swimming away from the light source, their probability of reorienting was reduced and photodispersal resulted.
Biological Weighting Function of the UV‐B‐induced Impairment of Phototaxis in the Freshwater Ciliate Ophryoglena flava¶
Authors: Marangoni Roberto , Marroni Fabio , Gioffré Domenico , Ghetti Francesco , Colombetti Giuliano 
Published: July 2010

AbstractWe determined the biological weighting function (BWF) of the effect of UV radiation on phototaxis of the freshwater, histophagous ciliate Ophryoglena flava. Dose‐effect curves were measured by exposing the cells to 12 different irradiation regimens obtained with two different levels of UV‐B radiation and by using six filters with cutoff wavelengths ranging from 280 to 335 nm. The results show that there are significant damages to phototaxis at the doses used and that the effect increases when the cutoff is shifted toward short wavelengths. The data were used to calculate the BWF of phototaxis impairment by applying a nonlinear fit procedure. The BWF thus obtained decays exponentially with increasing wavelength in agreement with similar findings reported in the literature for other systems.
Ship‐in‐a‐Bottle Synthesis of Fluorescence‐labeled Nanoparticles: Applications in Cellular Imaging¶
Authors: Chrétien Michelle N. , Shen Biao , García Hermenegildo , English Ann M. , Scaiano J. C. 
Published: July 2010

AbstractFluorescein (2‐(6‐hydroxy‐3‐oxo‐(3H)‐xanthen‐9‐yl) benzoic acid) has been prepared inside the pores of zeolite‐Y via ship‐in‐a‐bottle synthesis. Fluorescein, whose dimensions prevent it from entering through the ∼7 Å windows of the faujasite zeolite used, was prepared by the acid‐catalyzed reaction of resorcinol and phthalic anhydride. In this article we report initial spectroscopic data as well as an example of the usefulness of these fluorescence‐labeled nanoparticles for imaging applications such as confocal fluorescence microscopy. Encapsulated fluorescein shows a remarkable increase in photostability.
Surface Plasmon‐coupled Polarized Emission of N‐Acetyl‐l‐Trytophanamide¶
Authors: Gryczynski Ignacy , Malicka Joanna , Lukomska Joanna , Gryczynski Zygmunt , R. Lakowicz Joseph 
Published: July 2010

AbstractWe report an observation of ultraviolet (UV) surface plasmon‐coupled emission (SPCE) of N‐acetyl‐l‐tryptophanamide (NATA). The sample was spin coated from poly(vinyl alcohol) (PVA) solution on 20 nmaluminium film deposited on a quartz substracte. The directional UV SPCE occurs within a well‐defined narrow angle at 52dG from the normal to the coupling hemicylinder quartz prism. The NATA directional emission is highly p polarized as expected for surface plasmon‐coupled radiation.The 10 nm protective SiO2 layer deposited on top of the aluminum film significantly neutralized the fluorophore quenching by the metal surface. SPCE of NATA demonstratees a remarkable intrinsic dispersive property–the maximum of the emission spectrum depends on the observation angle. The efficient spectral resolution of SPCE can be used in the construction of miniaturized spectrofluorometers. The observation of SPCE of tryptophan opens a new possibility for the study of many unlabeled proteins with the technique complementary to surface plasmon resonance analysis.
Structural Requirements for Efficient Cellular Photoprotection by Carotenoid Derivatives¶†
Authors: Kanofsky Jeffrey R. , Sima Paul D. 
Published: July 2010

AbstractWe have synthesized five carotenoid derivatives: (1) Girard's reagent P (GRP)‐retinal from GRP and retinal; (2) GRP‐carotenal from GRP and β‐apo‐8′‐carotenal; (3) Girard's reagent T (GRT)‐carotenal from GRT and β‐apo‐8′‐carotenal; (4) (GRP)2‐canthaxanthin from 2 mol of GRP and 1 mol of canthaxanthin; and (5) dansyl hydrazine (DH)‐carotenal from DH and β‐apo‐8′‐carotenal. The first three derivatives are cations, whereas the fourth is a dication and the fifth is a weak base. Using K562 cells, we compared the subcellular distribution of the synthetic carotenoid derivatives with two uncharged natural carotenoids, β‐carotene and β‐apo‐8′‐carotenal. The two natural carotenoids were present mainly within the cell membranes. The synthetic carotenoid derivatives were more broadly distributed among the cell organelles. The positively charged derivatives had relatively high concentrations in mitochondria, whereas DH‐carotenal had a relatively high concentration in lysosomes. We also measured the amount of photoprotection provided by the synthetic and natural carotenoids for K562 cells labeled with a photosensitizer (hypericin, protoporphyrin IX or cis‐di[4‐sulfonatophenyl]diphenylporphine). In this model system, only carotenoid derivatives with a permanent positive charge provided significant photoprotection. Neither the two natural carotenoids nor DH‐carotenal were effective photoprotectors.
Laboratory UV Exposure: Risk Assessment and Protective Measures¶
Authors: Cazzuli Orietta , Giroletti Elio 
Published: July 2010

AbstractIn research laboratories ultraviolet radiation is widely used, particularly in photochemistry and photobiology, as a sterilizing agent and for the characterization of samples. The results of a survey conducted near several university laboratories are presented with the aim of quantifying exposure levels to UV‐incoherent radiation and to assess individual risk for researchers and students. It has been shown that exposure is not negligible, especially if safety procedures are neglected and personal protective equipments, described in this study, are not used.
Effect of Carotenoids and Monogalactosyl Diglyceride on Bacteriochlorophyll c Aggregates in Aqueous Buffer: Implications for the Self‐assembly of Chlorosomes¶
Authors: Klinger Pavel , Arellano Juan B. , Vácha František , Hála Jan , PšenčíK Jakub 
Published: July 2010

AbstractAggregation of bacteriochlorophyll (BChl) c from chlorosomes, the main light‐harvesting complex of green bacteria, has been studied in aqueous buffer. Unlike other chlorophyll‐like molecules, BChl c is rather soluble in aqueous buffer, forming dimers. When BChl c is mixed with carotenoids (Car), the BChl c Qy transition is further redshifted, in respect to that of monomers and dimers. The results suggest that Car are incorporated in the aggregates and induce further aggregation of BChl c. The redshift of the BChl c Qy band is proportional to the Car concentration. In contrast, the mixture of bacteriochlorophyllide (BChlide) c, which lacks the nonpolar esterifying alcohol, does not form aggregates with Car in aqueous buffer or nonpolar solvents. Instead, the position of the BChlide c Qy transition remains unshifted in respect to that of the monomeric molecule, and Car precipitates with the course of time in aqueous buffer. Similar effects on both BChl c and BChlide c are also observed when monogalactosyl diglyceride (MGDG), which forms the monolayer envelope of chlorosomes, is used instead of (or together with) Car. The results show that the hydrophobic interactions of the BChl c esterifying alcohols with themselves and the nonpolar carbon skeleton of Car, or the fatty acid tails of MGDG, are essential driving forces for BChl aggregation in chlorosomes.
An Evaluation of Exogenous Application of Protoporphyrin IX and its Dimethyl Ester as a Photodynamic Diagnostic Agent in Poorly Differentiated Human Nasopharyngeal Carcinoma¶
Authors: Tammilmani Vanaja , Yee Karen kar Lye , Heng Paul Wan Sia , Soo Khee Chee , Ollvo Mallni 
Published: July 2010

Abstract5‐Aminolevulinic acid and its esterified analogues have been under much investigation to enhance the endogenous production of protoporphyrin IX (PpIX) in tumor cells. However, in this work, we studied the in vitro and in vivo efficacy of exogenously administered PpIX and its esterified analogue, PpIX dimethyl ester (PME), in poorly differentiated human nasopharyngeal carcinoma (NPC/CNE‐2) as a photodynamic diagnostic (PDD) agent. NPC/CNE‐2 at its earliest time, 1 h after incubation with PME in in vitro studies, has exhibited 64% (P < 0.01) higher tumor to normal cell (T/N) fluorescence ratio than with PpIX. In an in vivo mouse xenograft model, comparable photosensitizer concentration in tumor after intravenous administration was observed at 1–3 h time points, but at 9 h, PME had 31% (P = 0.05) greater concentration in tumor compared with PpIX. In addition, by constituting PME and PpIX in different topical gel composites, of which, PME gel composition of 8:2 Plasdone® and Gantrez® resulted in the highest T/N ratio at 6 h after application (34%; P < 0.05) in comparison with other gel composites. Evaluation of PME and PpIX constituted in the delivery vehicles investigated showed comparable selectivity for tumor at 1–3 h, thus neither photosensitizer is more efficient than the other for PDD at the early time points; however, beyond 6 h, PME had higher selectivity for tumor compared with PpIX. Thus, further investigation is warranted to improve the drug delivery vehicle for greater tumor selectivity at a shorter incubation time.
Separation, Identification and Quantification of Riboflavin and its Photoproducts in Blood Products using High‐performance Liquid Chromatography with Fluorescence Detection: A Method to Support Pathogen Reduction Technology¶
Authors: Hardwick Christopher C. , Herivel Troy R. , Hernandez Shiloh C. , Ruane Patrick H. , Goodrich Raymond P. 
Published: July 2010

AbstractA medical device using riboflavin (RB) and light is being developed for the reduction of pathogens in platelet concentrates (MIRASOLTM pathogen reduction technology [PRT]). A high‐performance liquid chromatography (HPLC) method for the quantification of RB and its main photoproduct, lumichrome (LC) in blood components has been developed and validated. In addition, the same method has been used to identify and quantify the presence of additional photoproducts‐catabolites of RB. Levels of these agents before and after treatment as well as endogenous levels present in normal donor blood are reported using this analytical technique. The method allows for quantitative and qualitative analysis of RB and LC in blood components using HPLC fluorescence detection, a Zorbax® SB‐CN (stable bond cyano) column and a methanol‐water mobile phase. Quantitation and qualitative analysis of additional photoproducts of RB was also performed, but the method has not been validated for these other components. The method described has passed an 8 day validation and has been found to be adequate for its intended use. The range of the method for RB is 0.016–1.500 μM and for LC is 0.060–1.500 μM. The method detection limit for RB is 0.0006 μM and for LC is 0.012 μM. The acceptance criteria for repeatability were met; the relative standard deviation for RB was 0.64% and for LC was 0.76%. The acceptance criteria for bias were met with a 97% average recovery for RB and a 102% recovery for LC. Samples were centrifuged and diluted 1:50 with 0.9% saline before analysis. No protein precipitation or extraction was required. A mass balance of approximately 93.4–94.4% was achieved after exposure of products to UV light in the intended pathogen reduction treatment method. The method permitted the identification of photoproducts in blood that were both naturally occurring and produced after photolysis of blood samples treated with the PRT process. The identity of these photoproducts has been established using HPLC Tandem Mass Spectrometry (MS/MS) and UV spectroscopic methods and has been correlated with known metabolites and catabolites of RB. HPLC with fluorescence detection using a reverse phase cyano‐column allows for accurate separation, identification and quantification of both RB and LC in blood products without the need for solvent extraction or protein precipitation. Additional photoproducts could also be identified and quantified using this method. The presence of these agents in normal, untreated blood suggests that their presence in blood is ubiquitous.