bluuebunny/crossref_metadata_2025_split huggingface dataset:
Anthocyanins Protect Against A2E Photooxidation and Membrane Permeabilization in Retinal Pigment Epithelial Cells¶
Authors: Jang Young P. , Zhou Jilin , Nakanishi Koji , Sparrow Janet R. 
Published: July 2010

ABSTRACTThe pyridinium bisretinoid A2E, an autofluorescent pigment that accumulates in retinal pigment epithelial cells with age and in some retinal disorders, can mediate a detergent‐like perturbation of cell membranes and light‐induced damage to the cell. The photodynamic events initiated by the sensitization of A2E include the generation of singlet oxygen and the oxidation of A2E at carbon‐carbon double bonds. To assess the ability of plant‐derived anthocyanins to modulate adverse effects of A2E accumulation on retinal pigment epithelium (RPE) cells, these flavylium salts were isolated from extracts of bilberry. Nine anthocyanin fractions reflecting monoglycosides of delphinidin, cyanidin, petunidin and malvidin were obtained and all were shown to suppress the photooxidation of A2E at least in part by quenching singlet oxygen. The anthocyanins tested exhibited antioxidant activity of variable efficiency. The structural characteristics relevant to this variability likely included the ability to form a stable quinonoidal anhydro base at neutral pH, a conjugated diene structure in the C (pyrane) ring, the presence of hydroxyl groups on the B (benzene) ring and the relative hydrophobicity conferred by the arrangement of substituents on the B ring. Cells that had taken up anthocyanins also exhibited a resistance to the membrane permeabilization that occurs as a result of the detergent‐like action of A2E.
Time‐resolved Microscopy of ChromatinIn VitroandIn Vivo¶
Authors: Davis Sara K. , Bardeen Christopher J. 
Published: July 2010

ABSTRACTIn eukaryotic cell nuclei, double‐stranded DNA is found in the form of chromatin, a large fiber made up of DNA complexed to histone proteins. In this article, recent studies using fluorescence techniques to look at the dynamics of chromatin, bothin vivoandin vitro, are reviewed. Two‐photon counter‐propagating fluorescence recovery after patterned photobleaching is used to examine chromatin fluctuations on lengthscales ranging from less than 100 nm to microns. By combiningin vivostudies with data on isolated nuclei and by measuring how these fluctuations depend on variables like ionic strength and photochemical cross‐linking, it is demonstrated that the relatively large‐scale motions of chromatin observedin vivoare consistent with smaller scale modifications of the histone‐DNA interaction. This connection may provide a means to use conformational dynamics as anin vivoprobe of the biochemical events involved in gene expression.
Novel Aspects of Intrinsic and Extrinsic Aging of Human Skin: Beneficial Effects of Soy Extract¶
Authors: Südel Kirstin M. , Venzke Kirsten , Mielke Heiko , Breitenbach Ute , Mundt Claudia , Jaspers Sören , Koop Urte , Sauermann Kirsten , KnuBmann‐Hartig Elke , Moll Ingrid , Gercken Günther , Young Antony R. , Stäb Franz , Wenck Horst , Gallinat Stefan 
Published: July 2010

ABSTRACTBiochemical and structural changes of dermal connective tissue substantially contribute to the phenotype of aging skin. To study connective tissue metabolism with respect to ultraviolet (UV) exposure, we performed an in vitro (human dermal fibroblasts) and an in vivo complementary DNA array study in combination with protein analysis in young and old volunteers. Several genes of the collagen metabolism such as Collagen I, III and VI as well as heat shock protein 47 and matrix metalloproteinase‐1 are expressed differentially, indicating UV‐mediated effects on collagen expression, processing and degradation. In particular, Collagen I is time and age dependently reduced after a single UV exposure in human skin in vivo. Moreover, older subjects display a lower baseline level and a shorter UV‐mediated increase in hyaluronan (HA) levels. To counteract these age‐dependent changes, cultured fibroblasts were treated with a specific soy extract. This treatment resulted in increased collagen and HA synthesis. In a placebo‐controlled in vivo study, topical application of an isoflavone‐containing emulsion significantly enhanced the number of dermal papillae per area after 2 weeks. Because the flattening of the dermal‐epidermal junction is the most reproducible structural change in aged skin, this soy extract appears to rejuvenate the structure of mature skin.
Comparison by PAM Fluorometry of Photosynthetic Activity of Nine Marine Phytoplankton Grown Under Identical Conditions¶
Authors: Juneau P. , Harrison P. J. 
Published: July 2010

ABSTRACTThe photosynthetic activity of marine phytoplankton from five algal classes (Phaeodactylum tricornutum, Skeletonema costatum, Thalassiosira oceanica, Thalassiosira weissflogii, Dunaliella tertiolecta, Mantoniella squamata, Emiliania huxleyi, Pavlova lutheri and Heterosigma akashiwo) was investigated under identical growth conditions to determine interspecies differences. Primary photochemistry and electron transport capacity of individual species were examined by pulse amplitude‐modulated (PAM) fluorescence. Although few differences were found in maximal photosystem II (PSII) photochemical efficiency between various species, large differences were noticed in their PSII‐photosystem I (PSI) electron transport activity. We found that species such as T. oceanica and M. squamata have much lower photochemical activity than H. akashiwo. It appeared that processes involved in electron transport activity were more susceptible to change during algal evolution compared with the primary photochemical act close to PSII. Large variations in the nonphotochemical energy dissipation event among species were also observed. Light energy required to saturate photosynthesis was very different between species. We have shown that M. squamata and H. akashiwo required higher light energy (>1300 μmol m−2 s−1) to saturate photosynthesis compared with S. costatum and E. huxleyi (ca 280 μmol m−2 s−1). These differences were interpreted to be the result of variations in the size of lightharvesting complexes associated with PSII. These disparities in photosynthetic activity might modulate algal community structure in the natural environment where light energy is highly variable. Our results suggest that for an accurate evaluation of primary productivity from fluorescence measurements, it is essential to know the species composition of the algal community and the individual photosynthetic capacity related to the major phytoplankton species present in the natural phytoplankton assemblage.
Clinical Outcome of a Novel Photodynamic Therapy Technique Using Acridine Orange for Synovial Sarcomas¶
Authors: Kusuzaki Katsuyuki , Murata Hiroaki , Matsubara Takao , Miyazaki Shinichi , Shintani Ken , Seto Masashi , Matsumine Akihiko , Hosol Hajime , Sugimoto Touru , Uchida Atsumasa 
Published: July 2010

ABSTRACTSynovial sarcoma (SS) is one of common malignant softtissue tumors and is encountered most commonly in children and young adults. It frequently involves or invades major neurovascular structures and bones, and its local recurrence rate after simple resection has been reported to be as high as up to 80%. Because major nerves and vessels, as well as an adequate amount of bone, must be preserved to restore excellent limb function in cases of SS, a surgical technique entailing a low risk of local recurrence is needed. Based on the findings of recent experimental studies conducted by using a mouse osteosarcoma model, we developed a novel therapeutic technique for SS, consisting of reduction surgery followed by photodynamic therapy using acridine orange (AO‐PDT), with or without X‐ray irradiation at 5 Gy. A preliminary study revealed that low‐dose X‐rays also excite AO like photons. After an initial study on cell cultures, this novel technique was applied to six cases of SS. A follow‐up of the subjects to determine the clinical outcome revealed that none of the cases treated by AO‐PDT, including the four cases treated by additional 5 Gy irradiation and the two cases not receiving any radiation, showed any evidence of recurrence or local/systemic complications during the follow‐up period of 19‐51 months after the surgery. Therefore, we believe that AO‐PDT with 5 Gy irradiation may be an excellent novel therapeutic modality with reduction surgery to salvage excellent limb function in SS involving major nerves and vessels or bones.
UV Doses Worldwide¶†
Authors: Godar Dianne E. 
Published: July 2010

ABSTRACTUV radiation affects human health. Human exposure to UV radiation causes a few beneficial health effects like vitamin D3 formation but it causes many detrimental health effects: sunburn, ocular damage, photoaging, immune suppression, DNA damage and skin cancer. In countries with fair‐skinned populations, skin cancer is the most diagnosed of all cancers. In the United States in 2002, there were over one million new skin cancer cases. That means one out of every 285 people got skin cancer. Skin cancer of fair‐skinned individuals is increasing at an alarming rate (4–6% per year) around the world and has now reached so‐called “pandemic” proportions. Thus, it is important to know what UV doses people around the world get throughout their lives. This review covers how the outdoor UV doses are weighted for different biological effects, the most commonly used measuring devices for terrestrial and personal UV doses, the natural and other effects on terrestrial and personal UV doses, the time people spend outside, their ambient exposures and the terrestrial and personal UV doses of adult outdoor and indoor workers as well as children and adolescents around the world. Overall, outdoor‐working adults get about 10%, while indoor‐working adults and children get about 3% (2–4%) of the total available annual UV (on a horizontal plane). People's UV doses increase with increasing altitude and decreasing latitude; most indoor‐working adult Europeans get 10 000–20 000 J/m2 per year, Americans get 20 000–30 000 J/m2 per year and Australians are estimated to get 20 000–50 000 J/m2 per year (excluding vacation, which can increase the dose by 30% or more).
Drug Delivery of Aminolevulinic Acid from Topical Formulations Intended for Photodynamic Therapy¶
Authors: Donnelly Ryan F. , McCarron Paul A. , Woolfson A. David 
Published: July 2010

ABSTRACTTopical photodynamic therapy is used for a variety of malignant and pre‐malignant skin disorders, including Bowen's Disease and Superficial Basal Cell Carcinoma. A haem precursor, typically 5‐aminolevulinic acid (ALA), acting as a prodrug, is absorbed and converted by the haem biosynthetic pathway to photoactive protoprophyrin IX (PpIX), which accumulates preferentially in rapidly dividing cells. Cell destruction occurs when PpIX is activated by an intense light source of appropriate wavelength. Topical delivery of ALA avoids the prolonged photosensitivity reactions associated with systemic administration of photo‐sensitisers but its clinical utility is influenced by the tissue penetration characteristics of the drug, its ease of application and the stability of the active agent in the applied dose. This review, therefore, focuses on drug delivery applications for topical, ALA‐based PDT. Issues considered in detail include physical and chemical enhancement strategies for tissue penetration of ALA and subsequent intracellular accumulation of PpIX, together with formulation strategies and drug delivery design solutions appropriate to various clinical applications. The fundamental aspects of drug diffusion in relation to the physicochemical properties of ALA are reviewed and specific consideration is given to the degradation pathways of ALA in formulated systems that, in turn, influence the design of stable topical formulations.
The Influence of the Ethanol‐water Molar Ratio in the Precursor Solution on Morphology and Photocatalytic Activity of Pyrolytic ZnO Films¶
Authors: Quintana Maria , Rodriguez Juan , Solis José , Estrada Walter 
Published: July 2010

ABSTRACTZinc oxide films were fabricated by a homemade spray pyrolysis system equipped with an optical setup ensuring the in situ control of the film growth. Zinc acetate (0.1 M) diluted in a mixture of ethanol and water was used as the precursor solution. The ethanol‐water molar ratio, Γ, in the precursor solution was varied from 0 to 0.92. The deposition temperature and the pH of the precursor solution were kept at 350°C and 4.5, respectively. X‐ray diffraction patterns revealed that films were zincitelike with a grain size depending on the ethanol‐water molar ratio in the precursor solution. The interference pattern obtained during film deposition was used to monitor the film roughness; it was found that this is related with those results of surfaces and optical analysis obtained by scanning electron microscopy and spectrophotometric measurements, respectively. The morphology of the ZnO films obtained from Γ equal to either 0 or 0.92 are dense with agglomerates uniformly distributed, whereas the films obtained from Γ equal to either 0.03 or 0.06 are very rough with irregular agglomerates. The films obtained from Γ equal to 0.12, 0.18 and 0.31 are rough. Photoelectrocatalytic results indicated that there is a correlation of the partial molar volume of ethanol with respect to water in the spraying solution, with the photocatalytic efficiency of the ZnO films. We found that the maximum photodegradation of methyl orange in the solution occurs using ZnO films obtained with Γ= 0.12.
Laser Flash Photolysis in a O3/Cl2 Mixture at 266 nm in a Very Low‐Pressure Flow System¶
Authors: Codnia Jorge , Manzano Francisco , Azcárate María Laura 
Published: July 2010

ABSTRACTThe laser flash photolysis in a very low‐pressure flow system with mass spectrometry detection technique was developed for the study of oxidation reactions of chlorofluorocarbons. In this work, we have studied the UV photolysis of O3 in the presence of Cl2 at room temperature, which presents two catalytic cycles of O3 depletion with efficiencies dependent on the partial pressures in the photoreactor. The ozone dissociation was initiated with fourth harmonic pulses of a Nd:YAG laser. The detection of the reactants and the final and intermediate reaction products was performed with real‐time mass spectrometry. The variations of the O3, Cl2 and ClO concentration were measured. The equations system associated to a proposed kinetic scheme was solved numerically and excellent agreement with the experimental results was obtained. The results from this work allowed the determination of the wall loss rates of the O(1D), Cl and ClO radicals.
Impact of Solar Ultraviolet Radiation on Marine Phytoplankton of Patagonia, Argentina¶
Authors: Helbling E. Walter , Barbieri Elena S. , Marcoval M. Alejandra , Gonçalves Rodrigo J. , Villafañe Virginia E. 
Published: July 2010

ABSTRACTPatagonia area is located in close proximity to the Antarctic ozone “hole” and thus receives enhanced ultraviolet B (UV‐B) radiation (280–315 nm) in addition to the normal levels of ultraviolet A (UV‐A; 315–400 nm) and photosynthetically available radiation (PAR; 400‐700 nm). In marine ecosystems of Patagonia, normal ultraviolet radiation (UVR) levels affect phytoplankton assemblages during the three phases of the annual succession: (1) prebloom season (late summer‐fall), (2) bloom season (winter‐early spring) and (3) postbloom season (late spring‐summer). Small‐size cells characterize the pre‐and postbloom communities, which have a relatively high photosynthetic inhibition because of high UVR levels during those seasons. During the bloom, characterized by micro‐plankton diatoms, photosynthetic inhibition is low because of the low UVR levels reaching the earth's surface during winter; this community, however, is more sensitive to UV‐B when inhibition is normalized by irradiance (i.e. biological weighting functions). In situ studies have shown that UVR significantly affects not only photosynthesis but also the DNA molecule, but these negative effects are rapidly reduced in the water column because of the differential attenuation of solar radiation. UVR also affects photosynthesis versus irradiance (P vs E) parameters of some natural phytoplankton assemblages (i.e. during the pre‐ but not during the postbloom season). However, there is a significant temporal variability of P vs E parameters, which are influenced by the nutrient status of cells and taxonomic composition; taxonomic composition is in turn associated with the stratification conditions (e.g. wind speed and duration). In Patagonia, wind speed is one of the most important variables that conditions the development of the winter bloom by regulating the depth of the upper mixed layer (UML) and hence the mean irradiance received by cells. Studies on the interactive effects of UVR and mixing show that responses of phytoplankton vary according to the taxonomic composition and cell structure of assemblages; therefore cells use UVR if >90% of the euphotic zone is being mixed. In fact, cell size plays a very important role when estimating the impact of UVR on phytoplankton, with large cells being more sensitive when determining photosynthesis inhibition, whereas small cells are more sensitive to DNA damage. Finally, in long‐term experiments, it was determined that UVR can shape the diatom community structure in some assemblages of coastal waters, but it is virtually unknown how these changes affect the trophody‐namics of marine systems. Future studies should consider the combined effects of UVR on both phytoplankton and grazers to establish potential changes in biodiversity of the area.
Induced and Photoinduced DNA Damage by Quinolones: Ciprofloxacin, Ofloxacin and Nalidixic Acid Determined by Comet Assay¶
Authors: Sánchez Georgina , Hidalgo María Eliana , Vivanco José Miguel , Escobar Jorge 
Published: July 2010

ABSTRACTQuinolones are degraded by light with loss of their antimicrobial activity, generating active species or radicals, Evidence exists that some fluoroquinolones (lomefloxacin, fleroxacin and enoxacin) induce damage to the cellular membrane and DNA cleavage by photosensitization. In this study, the genotoxic potential of the quinolones ofloxacin, nalidixic acid and ciprofloxacin (three antimicrobials frequently used in therapy) was evaluated upon irradiation with UV light by using the comet assay on cells of the Jurkat line. The results demonstrate that there are significant differences between the control groups (positive control with 50 μM H2O2, negative controls without drug and with and without irradiation) and the groups of irradiated quinolones (ofloxacin 2.76 × 10−5M, nalidixic acid 2.15 × 10−4M and ciprofloxacin 2.01 × 10−5M), indicating that, at the dose of irradiation employed (necessary to produce 50% photodegradation), the photodecomposition of the quinolones enhanced DNA damage. The unirradiated drugs also exhibited genotoxicity significantly different from that of the negative control.
Spectral Properties of Topical Retinoids Prevent DNA Damage and Apoptosis After Acute UV‐B Exposure in Hairless Mice¶
Authors: Sorg O. , Iran C. , Carraux P. , Grand D. , Hügin A. , Didierjean L. , Saurat J.‐H. 
Published: July 2010

ABSTRACTWe showed in a recent study that topical retinyl palmitate prevented UV‐B‐induced DNA damage and erythema in humans. Given that retinyl palmitate is a precursor of retinoic acid, the biological form of vitamin A that acts through nuclear receptors, we wondered whether these protective effects toward UV‐B exposure were either receptor dependent or linked to other properties of the retinoid molecule such as its spectral properties. We determined the epidermal retinoid profile induced by topical retinoic acid in hairless mice and analyzed its effect on markers of DNA photodamage (thymine dimers) and apoptosis following acute UV‐B exposure; we compared these effects to those induced by other natural topical retinoids (retinaldehyde, retinol and retinyl palmitate) which do not directly activate the retinoid receptors. We then analyzed the direct action of these retinoids on UV‐B‐induced DNA damage and apoptosis in cultured A431 keratinocytes. Topical retinoic acid significantly decreased (∼50%) the number of apoptotic cells, as well as the formation of thymine dimers in the epidermis of mice exposed to acute UV‐B. Interestingly, the other topical retinoids decreased apoptosis and DNA damage in a similar way. On the other hand, neither retinoic acid nor the other retinoids interfered with the apoptotic process in A431 keratinocytes exposed to UV‐B, whereas DNA photodamage was slightly decreased. We conclude that the decrease of apoptotic cells in hairless mouse epidermis following topical retinoids and UV‐B irradiation reflects a protection of the primary targets of UV‐B (DNA) by a mechanism independent of the activation of retinoid nuclear receptors, rather than a direct inhibition of apoptosis.
Standard Ultraviolet Daylight for Nonextreme Exposure Conditions¶
Authors: Christiaens François J. , Chardon Alain , Fourtanier Anny , Frederick John E. 
Published: July 2010

ABSTRACTThe skin is exposed to ultraviolet radiation (UVR) from natural or artificial sources on a daily basis. The effects of chronic low dose exposure merit investigation, even when these effects are neither conspicuous nor clinically assessable. The purpose of the present study was to define a relative spectral UV irradiance that is representative of frequent nonextreme sun exposure conditions and therefore more appropriate for studies of the long‐term and daily effects of solar UV on the skin. Solar spectral UV irradiance values were calculated for different dates and locations by using a radiative transfer model. The spectral irradiance values obtained when the solar elevation is lower than 45° were averaged. An important feature is the dUVA (320–400 nm) to dUVB (290–320 nm) irradiance values ratio, which was found to be 27.3 for the overall average. When the months corresponding to extreme irradiance values (low or high) were excluded from the calculations, the dUVA to dUVB ratio ranged from 27.2 to 27.5. The mean spectral irradiance of the model presented here represents environmental UV exposure conditions and can be used both as a standard to investigate the biological effects of a nonextreme UVR and to assess the effectiveness of products for daily skin protection.
Imaging of Photodynamically Generated Singlet Oxygen Luminescence In Vivo¶
Authors: Niedre Mark J. , Patterson Michael S. , Giles Anoja , Wilson Brian C. 
Published: July 2010

ABSTRACTWe describe a novel scanning‐laser system for imaging type‐II photodynamically generated singlet oxygen (1O2[1Δg]) luminescence and demonstrate it in vivo in an intradermal tumor model in mice. We verify the strong oxygen‐dependence of the signal and show that the images are near the practical resolution limit.