bluuebunny/crossref_metadata_2025_split huggingface dataset:
Efficacy of Different UV‐emitting Light Sources in the Induction of T‐cell Apoptosis¶
Authors: Novák Zoltán , Bérces Attila , Rontó Györgyi , Pállinger Éva , Dobozy Attila , Kemény Lajos 
Published: July 2010

ABSTRACTUltraviolet B(UV‐B) radiation is a modality widely used for the treatment of different skin diseases. One of the major mechanisms of UV‐B immunosuppression in this treatment modality is thought to be an apoptosis‐inducing effect on T cells infiltrating the skin. We examined the T‐cell apoptosis induction capacities of four different UV light sources, with and without UV filters. The xenon chloride (XeCl) laser proved to be the strongest apoptosis inducer. The use of a phtalic acid filter eliminated UV radiation almost completely below 300 nm, which resulted in a severe decrease in the apoptosis‐inducing capacity of different UV‐B sources. Using the results of the measurements with polychromatic UV light sources, the wavelength dependence of UV‐B light for the induction of T‐cell apoptosis was also determined. The regression line of the action spectrum demonstrated a continuous decrease from 290 to 311 nm. The apoptosis‐inducing capacity of the XeCl laser was almost four times higher than the calculated value according to the action spectrum, which might be attributed to the high irradiance of the laser as compared with nonlaser light sources.
Expressed Sequence Tag Analysis of the Dinoflagellate Lingulodinium polyedrum During Dark Phase¶
Authors: Tanikawa Naomi , Akimoto Hidetoshi , Ogoh Katsunori , Chun Wu , Ohmiya Yoshihiro 
Published: July 2010

ABSTRACTTo collect information on gene expression during the dark period in the luminous dinoflagellate Lingulodinium polyedrum, normalized complementary DNA (cDNA) libraries were constructed from cells collected during the first hour of night phase in a 12:12 h light‐dark cycle. A total of 4324 5′‐end sequence tags were isolated. The sequences were grouped into 2111 independent expressed sequence tags (EST) from which 433 groups were established by similarity searches of the public nonredundant protein database. Homology analysis of the total sequences indicated that the luminous dinoflagellate is more similar to land plants and animals (vertebrates and invertebrates) than to prokaryotes or algae. We also isolated three bioluminescence‐related (luciferase and two luciferinbinding proteins [LBP]) and 37 photosynthesis‐related genes. Interestingly, two kinds of LBP genes occur in multiple copies in the genome, in contrast to the single luciferase gene. These cDNA clones and EST sequence data should provide a powerful resource for future genome‐wide functional analyses for uncharacterized genes.
Chemical and Structural Changes in Blood Undergoing Laser Photocoagulation¶
Authors: Black John F. , Barton Jennifer Kehlet 
Published: July 2010

ABSTRACTThe treatment of cutaneous vascular lesions (port wine stains etc.) using lasers has been guided by theories based on the “cold” or room‐temperature optical properties of the hemoglobin target chromophore. We have recently presented evidence showing that under the influence of laser irradiation, the optical properties of blood in vitro are time and temperature dependent. Such complications are not currently subsumed into the in vivo theory. Here, we study the time‐domain optical properties of blood undergoing photocoagulation in vitro using two newly developed time‐resolved techniques. We also study the asymptotic effect of laser photocoagulation on the chemical and structural properties of the components of the blood matrix. We present evidence showing that the photocoagulation process involves significant changes in the optical absorption and scattering properties of blood, coupled with photothermally induced chemical and structural changes. We demonstrate the first use of a laser to deliberately generate magnetic resonance imaging contrast in vitro. We show that this technique offers significant potential advantages to in vivo intravenous chemical contrast agent injection.
Rose Bengal‐Sensitized Photooxidation of the Dipeptides l‐Tryptophyl‐l‐Phenylalanine, l‐Tryptophyl‐l‐Tyrosine and l‐Tryptophyl‐l‐Tryptophan: Kinetics, Mechanism and Photoproducts¶
Authors: Posadaz Ariana , Biasutti Alicia , Casale César , Sanz Jesús , Amat‐Guerri Francisco , García Norman A. 
Published: July 2010

ABSTRACTThe Rose Bengal‐sensitized photooxidations of the dipeptides l‐tryptophyl‐l‐phenylalanine (Trp‐Phe), l‐tryptophyl‐l‐tyrosine (Trp‐Tyr) and l‐tryptophyl‐l‐tryptophan (Trp‐Trp) have been studied in pH 7 water solution using static photolysis and time‐resolved methods. Kinetic results indicate that the tryptophan (Trp) moiety interacts with singlet molecular oxygen (O2(1Δg)) both through chemical reaction and through physical quenching, and that the photooxidations can be compared with those of equimolecular mixtures of the corresponding free amino acids, with minimum, if any, influence of the peptide bond on the chemical reaction. This is not a common behavior in other di‐ and polypeptides of photooxidizable amino acids. The ratio between chemical (kr) and overall (kt) rate constants for the interaction O2(1Δg)‐dipeptide indicates that Trp‐Phe and Trp‐Trp are good candidates to suffer photodynamic action, with krlkt values of 0.72 and 0.60, respectively (0.65 for free Trp). In the case of Trp‐Tyr, a lower krlkt value (0.18) has been found, likely as a result of the high component of physical deactivation of O2(1Δg) by the tyrosine moiety. The analysis of the photooxidation products shows that the main target for O2(1Δg) attack is the Trp group and suggests a much lower accumulation of kynurenine‐type products, as compared with free Trp. This is possibly because of the occurrence of another accepted alternative pathway of oxidation that gives rise to 3a‐oxidized hydrogenated pyrrolo[2,3‐b]indoles.
Tattoo Pigments are Cleaved by Laser Light‐The Chemical Analysis In Vitro Provide Evidence for Hazardous Compounds¶
Authors: Vasold Rudolf , Naarmann Natascha , Ulrich Heidi , Fischer Daniela , Könlg Burkhard , Landthaler Michael , Bäumler Wolfgang 
Published: July 2010

ABSTRACTIn the western world, more than 80 million people decorate their skin with tattoos. Tattoo colorants are injected into the skin, like medical drugs. Most tattoo colorants are industrial pigments, and chemical industries have never produced them for human use but only to stain consumer goods. Up to 10% of tattooed people request removal of their tattoos because of an improved self‐image or social stigmatization. In contrast to tattooing, physicians usually perform the tattoo removal. For that purpose laser light at very high intensities irradiates the skin to destroy the tattoo pigments. Based on a recent analysis of tattoo pigments, two widely used azo compounds were irradiated in suspension with laser and subsequently analyzed by using quantitative high‐performance liquid chromatography and mass spectrometry. The high laser intensities cleaved the azo compounds, leading to an increase of decomposition products such as 2‐methyl‐5‐nitroaniline,2‐5‐dichloraniline and 4‐nitro‐toluene, which are toxic or even carcinogenic compounds. Moreover, the results of the chemical analysis show that the tattoo colorants already contain such compounds before laser irradiation. Because of a high number of patients undergoing laser treatment of tattoos and based on the results of our findings in vitro, it is an important goal to perform a risk assessment in humans regarding laser‐induced decomposition products.
Photodynamic Treatment of the Dermatophyte Trichophyton rubrum and its Microconidia with Porphyrin Photosensitizers¶
Authors: Smijs Threes G. M. , van der Haas Richard N. S. , Lugtenburg Johan , Liu Yan , de Jong Rob L. P. , Schuitmaker Hans J. 
Published: July 2010

ABSTRACTThe application of photosensitizers for the treatment of fungal infections is a new and promising development within the field of photodynamic treatment (PDT). Dermatophytes, fungi that can cause infections of the skin, hair and nails, are able to feed on keratin. Superficial mycoses are probably the most prevalent of infectious diseases in all parts of the world. One of the most important restrictions of the current therapeutic options is the return of the infection and the duration of the treatment. This is especially true in the case of infections of the nail (tinea unguium) caused by Trichophyton rubrum, an anthropophilic dermatophyte with a worldwide distribution. Recently, we demonstrated that 5,10,15‐tris(4‐methylpyridinium)‐20‐phenyl‐[21H,23H]‐porphine trichloride (Sylsens B) and deuteroporphyrin monomethylester were excellent photosensitizers toward T. rubrum when using broadband white light. This study demonstrates the photodynamic activity of these photosensitizers with red light toward both a suspension culture of T. rubrum and its isolated microconidia. The higher penetration depth of red light is important for the PDT of nail infections. In addition, we tested the photodynamic activity of a newly synthesized porphyrin, quinolino‐[4,5,6,7‐efg]‐7‐demethyl‐8‐deethylmesoporphyrin dimethylester, displaying a distinct peak in the red part of the spectrum. However, its photodynamic activity with red light toward a suspension culture of T. rubrum appeared to be only fungistatic. Sylsens B was the best photosensitizer toward both T. rubrum and its microconidia. A complete inactivation of the fungal spores and destruction of the fungal hyphae was found. In studies into the photostability, Sylsens B appeared to be photostable under the conditions used for fungal PDT. A promising result of this study is the demonstration of the complete degradation of the fungal hyphae in the time after the PDT and the inactivation of fungal spores, both with red light. These results offer the ingredients for a future treatment of fungal infections, including those of the nail.
Bioluminescence Imaging of the Response of Rat Gliosarcoma to ALA‐PpIX‐mediated Photodynamic Therapy¶
Authors: Moriyama Eduardo H. , Bisland Stuart K. , Lilge Lothar , Wilson Brian C. 
Published: July 2010

ABSTRACTPhotodynamic therapy (PDT) is a promising modality for the treatment of solid tumors that combines a photosensitizing agent and light to produce cytotoxic reactive oxygen species that lead to tumor cell death. The recent introduction of bioluminescence imaging (BLI), involving the use of the luciferase gene (luc) transferred into target tumor cells, followed by systemic administration of luciferin and detection of the emitted visible chemiluminescence photons, offers the potential for longitudinal imaging of tumor growth and therapeutic response in single animals. We demonstrate in this study the first results of the use of BLI to assess the response of an intracranial brain tumor model (9L rat gliosarcoma) to aminolevulinic acid (ALA)‐mediated PDT. Complementary in vitro experiments with the luciferase‐transfected 9L cells show that the decrease in the luminescent signal after PDT correlates with cell kill. In vivo imaging shows a decrease in the BLI signal from the tumor after ALA‐PDT treatment, followed by tumor regrowth. Furthermore, preliminary studies using cells transfected with a hypoxiaresponsive vector show an increase in bioluminescence within 4 h after Photofrin‐mediated PDT, demonstrating the ability to observe stress‐gene responses. These results suggest that BLI can be used to provide spatiotemporal information of intracranial brain tumor responses after PDT and may serve as a valuable response‐endpoint measure.
Lifetime of Fluorescent Pyrene Butyric Acid Probe in Single Living Cells for Measurement of Oxygen Fluctuation¶
Authors: Ribou Anne‐Cecile , Vigo Jean , Salmon Jean‐Marie 
Published: July 2010

ABSTRACTWe study the fluorescence lifetime of the well‐known 1‐pyrene butyric acid (PBA) to assess oxygen concentrations in living cells. The behavior of the probe is first studied in water, ethanol, protein solution and liposome suspension. The Stern‐Volmer plot of these solutions is linear, and the bimolecular reaction rate constant agrees with previous observations. In single living cells, the PBA lifetime decreases with oxygen concentration (185 to 55 ns). The probe lifetime differences between living cells and liposome suspension, especially under nitrogen atmosphere, suggest a supplemental pathway for the deactivation of the probe. We simplify further the complex living cells system by stopping the cell functions and studying freshly fixed cells. In this case, we obtained an increase of PBA lifetime under nitrogen atmosphere (215 ns).
Involvement of Human Small Fragment Nuclease in the Resistance of Human Cells to UV‐C‐induced Cell Death¶
Authors: Ito Seiro , Kita Kazuko , Zhal Ling , Wano Chieko , Suzuki Toshikazu , Yamaura Akira , Suzuki Nobuo 
Published: July 2010

ABSTRACTHuman small fragment nuclease (Sfn) is one of the cellular proteins that were reported to degrade small, single‐stranded DNA and RNA. However, the biological role of Sfn in cellular response to various stressors such as UV‐C (mainly 254 nm wavelength ultraviolet ray) remains unclear. We have examined whether modulation of human SFN gene expression affects cell survival capacity against UV‐C‐induced cell death, analyzing colony survival ability in UV‐C‐sensitive human RSa cells treated with short double‐stranded RNA (siRNA) specific for SFN messenger RNA (mRNA). The expression levels of SFN mRNA in the siRNA‐treated RSa cells decreased to about 15% compared with those in the control siRNA‐treated cells. The siRNA‐treated RSa cells showed lower colony survival and higher activity of caspase‐3 after UV‐C irradiation than the control siRNA‐treated RSa cells. Furthermore, the removal capacity of cyclobutane pyrimidine dimers (CPD) in the siRNA‐treated RSa cells decreased compared with the control siRNA‐treated RSa cells. There was no difference in the colony survival and CPD removal capacity after UV‐C irradiation between the control siRNA‐treated RSa cells and mock‐treated RSa cells. These results suggest that SFN expression is involved in resistance of RSa cells to UV‐C‐induced cell death through the roles it plays in the DNA repair process.
Estimating UV Erythemal Irradiance by Means of Neural Networks¶
Authors: Alados Inmaculada , Mellado José Antonio , Ramos Francisca , Alados‐Arboledas Lucas 
Published: July 2010

ABSTRACTIn recent years, there has been a substantial increase in attempts to model the flux of ultraviolet radiation (UV). UV irradiance at surface level is a result of the combined effects of solar zenith angle, surface elevation, cloud cover, aerosol load and optical properties, surface albedo and the vertical profile of ozone. In this study, we present the development of an artificial neural network (ANN) model that can be used to estimate solar UV irradiance on the basis of optical air mass, ozone columnar content, latitude, horizontal visibility data and cloud information such as type, coverage and height. ANN are widely accepted as a technology offering an alternative way to tackle complex and ill‐defined problems. They can learn from examples, are fault tolerant in the sense that they are able to handle noisy and incomplete data, are able to deal with nonlinear problems and, once trained, can perform prediction and generalization at high speed. In this study, a multilayer perceptron network (MLP) consisting of an input layer, an output layer and one hidden layer was used. Training of the neural network was done using the Bayesian regulation back propagation algorithm. The study was developed using data from three stations on the Iberian Peninsula: Madrid and Murcia during the period 2000–2001 and Zaragoza in 2001. To train and validate the MPL neural networks, independent subsets of data were extracted from the complete database at each station. The results suggest that a MLP neural network using optical air mass, ozone columnar content, latitude and total cloud coverage provides the best estimates, with mean bias deviation and root mean square deviation of −0.1% and 18.0%, 1.6% and 19.6%, 0.1% and 14.6% at Madrid, Murcia and Zaragoza, respectively. Despite the dependence of the cloud radiative effect on cloud type, the use of additional information such as cloud type or cloud elevation did not improve these results. The performance of the developed ANN has been checked regarding its ability to estimate the UV index (UVI); results indicate that in more than 95% of the cases, the difference between estimated and measured values does not exceed one unit of UVI.
Phototoxic Effect of Visible Light on Porphyromonas gingivalis and Fusobacterium nucleatum: An In Vitro Study¶†
Authors: Feuerstein Osnat , Persman Nir , Weiss Ervin I. 
Published: July 2010

AbstractThe antibacterial effect of visible light irradiation combined with photosensitizers has been reported. The objective of this was to test the effect of visible light irradiation without photosensitizers on the viability of oral microorganisms. Strains of Porphyromonas gingivalis, Fusobacteriurm nucleatum, Streptococcus mutans and Streptococcus faecalis in suspension or grown on agar were exposed to visible light at wavelengths of 400–500 nm. These wavelengths are used to photopolymerize composite resins widely used for dental restoration. Three photocuring light sources, quartz‐tungsten‐halogen lamp, light‐emitting diode and plasma‐arc, at power densities between 260 and 1300 mW/cm2 were used for up to 3 min. Bacterial samples were also exposed to a near‐infrared diode laser (wavelength, 830 nm), using identical irradiation parameters for comparison. The results show that blue light sources exert a phototoxic effect on P. gingivalis and F. nucleatum. The minimal inhibitory dose for P. gingivalis and F. nucleatum was 16–62 J/cm2, a value significantly lower than that for S. mutans and S. faecalis (159–212 J/cm2). Near‐infrared diode laser irradiation did not affect any of the bacteria tested. Our results suggest that visible light sources without exogenous photosensitizers have a phototoxic effect mainly on Gram‐negative periodontal pathogens.
A Phytochrome‐like Protein AphC Triggers the cAMP Signaling Induced by Far‐red Light in the Cyanobacterium Anabaena sp. Strain PCC7120¶
Authors: Okamoto Shinobu , Kasahara Masahiro , Kamlya Asako , Nakahira Yuka , Ohmori Masayuki 
Published: July 2010

ABSTRACTIn the filamentous, nitrogen‐fixing cyanobacterium Anabaena sp. PCC7120, red light (630 nm) decreased, whereas far‐red light (720 nm) increased cellular adenosine 3′,5′‐cyclic monophosphate (cAMP) content. To find a red and far‐red light photoreceptor that triggers the cAMP signal cascade, we disrupted 10 open reading frame having putative chromophore‐binding GAF domains. The response of the cellluar cAMP concentration to red and far‐red light in each open reading frame disruptant was determined. It was found that only the mutant of the gene all2699 failed to respond to far‐red light. The open reading frame named as aphC encoded a protein with 920 amino acids including GAF domains similar to those involved in Cph2, a photoreceptor of Synechocystis sp. PCC6803. To determine which adenylate cyclase (AC) is responsible for far‐red light signal, we disrupted all AC genes and found that CyaC was the candidate. The enzymatic activity of CyaC might be controlled by a far‐red light photoreceptor through the phosphotransfer reaction. The site‐specific mutant of the Asp59 residue of the receiver (R1) domain of CyaC lost its light‐response capability. It was suggested that the far‐red light signal was received by AphC and then transferred to the N‐terminal response regulator domain of CyaC. Then its catalytic activity was stimulated, which increased the cellular cAMP concentration and drove the subsequent signal transduction cascade.
Evidence for Intracellular Aggregation of Hypericin and the Impact on its Photocytotoxicity in PAM 212 Murine Keratinocytes¶
Authors: Theodossiou Theodossis , Spiro Michael D. , Jacobson Jake , Hothersall John S. , MacRobert Alexander J. 
Published: July 2010

AbstractWe have assessed photoinduced toxicity of hypericin in PAM 212 murine keratinocytes and the relationship between concentration, incubation time and light fluence to evaluate the effect of intracellular aggregation at high concentrations. Confocal microscopy was used to establish the subcellular localization of hypericin at 5 and 50 μM and incubation times of 1 and 3 h. From fluorescence uptake time course studies, intracellular hypericin was demonstrated to exist predominantly in the monomeric form for up to 26 h incubation at 5 μM. However, there was a pronounced aggregation effect at 50 μM, with intracellular hypericin fluorescence levels initially showing an increase followed by a decrease with incubation time. This effect was subsequently shown to exert an effect on the phototoxicity of hypericin. On irradiation, the photocytotoxicity for 1 and 7 h incubation with 50 μM hypericin was comparable, whereas using 5 μM the photocytotoxicity showed good correlation with the intracellular fluorescence measurements at 1 and 7 h incubation.
Reflectance Spectra of Pigmented and Nonpigmented Skin in the UV Spectral Region¶
Authors: Nielsen Kristian P. , Zhao Lu , Juzenas Petras , Stamnes Jakob J. , Stamnes Knut , Moan Johan 
Published: July 2010

AbstractWe present measurements of reflectance spectra from human skin in vivo in the spectral range from 250 to 700 nm. These measurements show that the reflectance from strongly pigmented skin is higher than that from weakly pigmented skin at wavelengths shorter than approximately 300 nm. We simulate the measured results using a new radiative transfer model developed to study light propagation in skin tissue. Our simulations mimic the measured spectra when scattering from melanosomes, and fragmented melanosomes are taken into account. Scattering from microstructures with high relative refractive indices plays a major role in tissue optics. Our results show that scattering from melanosomes and fragmented melanosomes is of particular significance.
Effect of Netropsin on One‐electron Oxidation of Duplex DNA¶†
Authors: Roberts Lezah W. , Schuster Gary B. 
Published: July 2010

AbstractThe effect of netropsin on the oxidative reactions of duplex DNA was examined. One‐electron oxidation of DNA creates a radical cation that migrates through duplex DNA and reacts primarily at GG steps. Netropsin is a dication that specifically binds primarily by hydrogen bonding in the minor groove at sites that have four or more contiguous A‐T base pairs. We showed that the oxidation potential of netropsin is less than that of any of the four nucleobases. We find that netropsin quenches the oxidative reactions of DNA independent of whether it is specifically bound. Within the Perrin model of static quenching, a netropsin within a rather large fixed volume around the DNA is an effective quencher.