bluuebunny/crossref_metadata_2025_split huggingface dataset:
Influence of Eicosapentaenoic Acid, an Omega‐3 Fatty Acid, on Ultraviolet‐B Generation of Prostaglandin‐E2 and Proinflammatory Cytokines Interleukin‐1β, Tumor Necrosis Factor‐α, Interleukin‐6 and Interleukin‐8 in Human Skin In Vivo¶
Authors: Shahbakhti Hassan , Watson Rachel E. B. , Azurdia Richard M. , Ferreira Christiana Z. , Garmyn Marjan , Rhodes Lesley E. 
Published: July 2010

ABSTRACTDietary omega‐3 polyunsaturated fatty acids (ω‐3 PUFA) reduce sunburn, an acute inflammatory response, in humans, We assessed whether this may be mediated by reduced ultraviolet‐B (UV‐B) induction of proinflammatory mediators tumor necrosis factor‐α (TNF‐α), interleukin (IL)‐1β, IL‐6, IL‐8 and prostaglandin (PG)E2 in healthy skin. In a double‐blind, randomized study, 28 humans received 4 g daily of 95% ethyl esters of eicosapentaenoic acid (EPA) or oleic acid (OA) orally for 3 months. Skin biopsies and suction blister fluid were taken from unexposed and UV‐B‐exposed skin and examined for mediator expression immunohistochemically and quantitatively by immunoassay; plasma levels were also assayed. The subjects taking EPA, but not OA, showed a significant rise in their minimal erythemal dose (MED) (data reported elsewhere). Before supplementation, irradiation with 3X MED UV‐B increased blister fluid TNF‐α, IL‐6, IL‐8 and PGE2 at 16 h (all P < 0.001). No significant change occurred in baseline or UV‐B‐induced skin levels of cytokines after either supplement, whereas UV‐B induction of PGE2 was abolished after EPA but not OA. Immunohistochemical expression of the cytokines at baseline and after UV‐B was unaltered by EPA and OA; circulating cytokine and PGE2 levels were also unchanged. Hence, in healthy skin in vivo, there was no evidence that reduction of the sunburn response by EPA is mediated by the proinflammatory cytokines examined; abrogation of UV‐B‐generated PGE2, may play a role.
Comparative Sensitivity of Microvascular Endothelial Cells, Fibroblasts and Tumor Cells after In Vitro Photodynamic Therapy with meso‐Tetra‐Hydroxyphenyl‐Chlorin¶
Authors: Triesscheijn Martijn , Ruevekamp Marjan , Aalders Maurice , Baas Paul , Stewart Fiona A. 
Published: July 2010

ABSTRACTThe phototoxic effect of meso‐tetra‐hydroxyphenyl‐chlorin (mTHPC)‐mediated photodynamic therapy (PDT) on human microvascular endothelial cells (hMVEC) was compared with that on human fibroblasts (BCT‐27) and two human tumor cell lines (HMESO‐1 and HNXOE). To examine the relationship between intrinsic phototoxicity and intracellular mTHPC content, we expressed cell survival as a function of cellular fluorescence. On the basis of total cell fluorescence, HNXOE tumor cells were the most sensitive and BCT‐27 fibroblasts the most resistant, but these differences disappeared after correcting for cell volume. Endothelial cells were not intrinsically more sensitive to mTHPC‐PDT than tumor cells or fibroblasts. Uptake of mTHPC in hMVEC increased linearly to at least 48 h, whereas drug uptake in the other cell lines reached a maximum by 24 h. No difference in drug uptake was seen between the cell lines during the first 24 h, but by 48 hMVEC had a 1.8‐ to 2.8‐ fold higher uptake than other cell lines. Endothelial cells showed a rapid apoptotic response after mTHPC‐mediated PDT, whereas similar protocols gave a delayed apoptotic or necrotic like response in HNXOE. We conclude that endothelial cells are not intrinsically more sensitive than other cell types to mTHPC‐mediated PDT but that continued drug uptake beyond 24 h may lead to higher intracellular drug levels and increased photosensitivity under certain conditions.
Energy Transfer and Fluorescence Quenching in Complexes of Polymethine Dyes with Human Serum Albumin¶
Authors: Tatikolov Alexander S. , Costa Sílvia M. B. 
Published: July 2010

ABSTRACTElectronic excitation energy transfer (EET) between molecules of polymethine dyes bound to human serum albumin (HSA) has been established and studied by absorption and fluorescence spectroscopy as well as by fluorescence decay measurements. In this system, excitation of the donor dye molecule leads to fluorescence of the acceptor dye molecule, both bound to HSA, with donor fluorescence quenching by the acceptor. The short distance between the donor and the acceptor (25‐28 Å) revealed from the Förster model of EET as well as some spectroscopic data show that both molecules are probably located in the same binding domain of HSA. The role of HSA is to bring donor and acceptor molecules together to a distance adequate to achieve EET as well as to increase the donor and acceptor fluorescence quantum yields. Efficient quenching of the intrinsic HSA fluorescence by some polymethine dyes (oxonols) is observed. The experimental results fit well a model for the formation of a weakly fluorescent dye‐HSA complex; the quencher in this complex should be located in the immediate vicinity of the HSA fluorophore group (Trp214).
The Effect of Molecular Environment on the Photoisomerization of Urocanic Acid¶
Authors: Wallis Richard A. , Smith Gerald J. , Dunford Cara L. 
Published: July 2010

ABSTRACTUrocanic acid, imidazole propenoic acid, is a metabolic product of histidine, which accumulates in skin and is excreted in sweat. It absorbs UV radiation at wavelengths shorter than 340 nm, and its principal photochemical reaction is a trans‐cis isomerization about the propenyl double bond. This isomerization to the biologically active cis isomer is implicated in the photo‐induced suppression of the immune system of skin. The kinetics of the trans→cis photoisomerization of urocanic acid has been determined in a number of solvents, spanning a range of polarities. The initial rates of isomerization and the photostationary trans‐cis compositions, in all solvents except water, correlate linearly with solvent polarity. This indicates that the isomerization proceeds through a polar intermediate that is stabilized by coulombic interactions with the molecular environment.
Photoinactivation of Hepatitis A Virus by Synthetic Porphyrins¶
Authors: Casteel Michael J. , Jayaraj K. , Gold Avram , Ball Louise M. , Sobsey Mark D. 
Published: July 2010

ABSTRACTPorphyrins are photosensitizers and may be applicable in situations where viral inactivation is required, as for in vitro inactivation of nonenveloped viruses in blood components or in other aqueous media. No study has examined the efficacy of porphyrin inactivation on human pathogens such as hepatitis A virus (HAV) in plasma or other liquids. Experiments were conducted to evaluate the effect of synthetic porphyrins on HAV in porphyrin‐containing human plasma and phosphatebuffered saline exposed to long‐wavelength (365 nm) UV light. Inactivation of bacteriophage MS2 (MS2) also was determined in some trials. Solutions containing cationic, anionic or amphiphilic porphyrins irradiated with an average light dose of 4.3 J/cm2 for 90 min resulted in >3 log10 (>99.9%) to >4 log10 (>99.99%) inactivation of both HAV and MS2. Viral inactivation may have been greater than observed because the limits of detection of the assay had been reached. Under ambient lighting conditions, none of the porphyrins was mutagenic in the Ames assay and only the congener with the longest chain‐length, tetrakis (N‐[n‐hexadecyl]‐4‐pyridiniumyl) porphyrin, was appreciably toxic to mammalian cells. Disinfection by photoactivated synthetic porphyrins therefore can offer an effective and relatively safe approach to removal of nonenveloped viruses from aqueous media.
Ground‐ and Excited‐state Proton Transfer Reaction of 3‐Hydroxyflavone in Dimyristoylphosphatidylcholine Liposome Membrane¶
Authors: Shyamala Thirunavukkuarasu , Mishra Ashok K. 
Published: July 2010

ABSTRACT3‐Hydroxyflavone (3HF), a molecule that exhibits excited‐state intramolecular proton transfer, has been studied for its fluorescence characteristics in dimyristoylphosphatidylcholine (DMPC) liposome membrane. 3HF partitions to the lipid bilayer membrane with a reasonably large partition coefficient. On excitation at 417 nm, a weak emission from the ground‐state anion species was observed at 483 nm, whereas excitation at absorption maxima (345 nm) gives the usual intense fluorescence of the phototautomeric emission at 530 nm. In this article, we report the observation of a ground‐state proton transfer reaction of 3HF in DMPC liposome membrane.
UV Absorption and Photoisomerixation of p‐Methoxycinnamate Grafted Silicone¶
Authors: Pattanaargson Supason , Hongchinnagorn Nantawan , Hirunsupachot Piyawan , Sritana‐anant Yongsak 
Published: July 2010

ABSTRACT p‐Methoxycinnamate moieties, UV‐B‐absorptive chromophores of the widely used UV‐B filter, 2‐ethylhexyl p‐methoxycinnamate (OMC), were grafted onto the 7 mol% amino functionalized silicone polymer through amide linkages. Comparing with OMC, the resulting poly [3(p‐methoxycinnamido)(propyl)(methyl)‐dimethyl] siloxane copolymer (CAS) showed less E to Z isomerization when exposed to UV‐B light. The absorption profiles of the product showed the maximum absorption wavelength to be similar to that of OMC but with less sensitivity to the type of solvent. Poly (methylhydrosiloxane) grafted with 10 mol%p‐methoxycinnamoyl moieties was prepared through hydrosilylations of 2‐propenyl‐p‐methoxycinnamate, in which the resulting copolymer showed similar results to those of CAS.
Radical Cation Generation from Singlet and Triplet Excited States of All‐trans‐Lycopene in Chloroform¶
Authors: Han Rui‐Min , Wul Yi‐Shi , Feng Juan , Ai Xi‐Cheng , Zhang Jian‐Ping , Skibsted Leif H. 
Published: July 2010

ABSTRACTOn direct photoexcitation, subpicosecond time‐resolved absorption spectroscopy revealed that the 1Bu‐type singlet excited state of all‐trans‐lycopene in chloroform was about seven times more efficient than all‐trans‐β‐carotene in generating the radical cation. The time constant of radical cation generation from the 1Bu‐type state was found to be ∼0.14 ps, a value that was comparable for the two carotenoids. On anthracene‐sensitized triplet excitation, radical cation generation was found to be much less efficient for lycopene than for β‐carotene. A slow rising phase (20‐30 μs) in the bleaching of ground‐state absorption was common for both lycopene and β‐carotene in chloroform and was ascribed to an efficient secondary reaction with a solvent radical leading to the formation of carotenoid radical cations. The reverse ordering in the tendency of the excited states of different multiplicities for the two carotenoids to generate radical cations is discussed in relation to the two carotenoids as scavengers of free radicals.
Spatial Distribution of Upper‐room Germicidal UV Radiation as Measured with Tubular Actinometry as Compared with Spherical Actinometry¶
Authors: Rahn Ronald O. 
Published: July 2010

ABSTRACTChemical actinometry of UV germicidal irradiation using sections of quartz tubing as compared with quartz spheres as irradiation vessels has been investigated. Vessels were either 3 mm inner diameter quartz tubing, 46 cm in length (tubular actinometry), or 1 cm quartz spheres (spherical actinometry). The vessels containing an iodide/iodate actinometric solution were suspended from the ceiling at 24 positions in a room (6 × 6 m) containing five germicidal lamp fixtures in the corners and in the center of the room. The lamp fixtures were louvered collimating the radiation in the horizontal (x, y) plane. Hence, the tubes, which span the depth of the radiation field, essentially integrate the radiation along the z‐axis for a given x, y position. The pseudospatial average fluence rate obtained using tubular actinometry was 18 mW/cm2 for the volume contained in the upper 46 cm (18 inch) of the room. Spherical actinometry, which measured the fluence rate in the center of the beam, provided an average value of 32 mW/cm2 over the volume of the beam. A comparison of the fluence rates obtained by these two methods allowed the average depth of the beam to be estimated as 26 cm. It is concluded that tubular actinometry is more advantageous than spherical actinometry for this application.
Probing the Active Site of Trypsin with Rose Bengal: Insights into the Photodynamic Inactivation of the Enzyme¶
Authors: Khajehpour Mazdak , Troxler Thomas , Vanderkool Jane M. 
Published: July 2010

ABSTRACTIn this work the active site of trypsin has been probed with the dye rose bengal. The dye binds competitively to the enzyme, and it can be used as a probe of the active site of the enzyme. On the basis of the emission wavelength, the binding site of trypsin is relatively polar and is similar to that of acetone in its polarity. The triplet state of rose bengal is quenched by trypsin. This quenching may be caused by the tryptophan and tyrosine residues that are in the near vicinity of the trypsin active site. This quenching can compete with the formation of singlet oxygen from the excited triplet state of rose bengal. We demonstrate that the singlet oxygen involved in the photoinactivation of trypsin is produced by the free rose bengal in solution and the bound dye is incapable of producing singlet oxygen. This explains the lack of correlation between photoinactivation efficiency and sensitizer binding capability previously reported by Wade and Spikes.
The Phase‐dependent Photochemical Reaction Dynamics of Halooxides and Nitrosyl Halides¶
Authors: Cooksey Catherine C. , Reid Philip J. 
Published: July 2010

AbstractRecent progress in understanding the phase‐dependent reactivity of halooxides and nitrosyl halides is outlined. Halooxide reactivity is represented by the photochemistry of chlorine dioxide (OCIO) and dichlorine monoxide (CIOCI). The gas phase photochemical dynamics of OCIO are contrasted with the dynamics in condensed environments. The role of excited‐state symmetry in defining the reaction dynamics and the observation of photoisomerization resulting in the production of CIOO are discussed. The current understanding of the excited‐state reaction dynamics of CIOCI and evidence for photoisomerization of this species resulting in the production of CICIO are outlined. Finally, the photochemical reaction dynamics of the nitrosyl halide CINO are presented. The main difference between the gas and condensed phase reaction dynamics of this species is that whereas photodissociation to form CI and NO dominates the gas phase reaction dynamics, photoisomerization resulting in CION production occurs to an appreciable extent in condensed environments. The observation of photoisomerization for OCIO, CIOCI and CINO suggests that this process is a general feature of the condensed phase reaction dynamics for smaller halooxides and nitrosyl halides. Finally, future areas for study in both halooxide and nitrosyl halide photoreactivity are outlined.
Lens α‐Crystallin and Hypericin: A Photophysical Mechanism Explains Observed Lens Damage¶†
Authors: Trevithick‐Sutton Colleen C. , Chin Khin K. , Contos Sotiria D. , Foote Christopher S. 
Published: July 2010

AbstractDetermining whether α‐crystallin (the major lens protein) affects the photophysics of hypericin, a photosensitizing agent found in various plants, such as St. John's Wort, is important. Hypericin shows promise in cancer and human immunodeficiency virus therapy but may harm individuals taking St. John's Wort extracts (for mild to moderate depression). Hypericin causes hypericism, which is characterized by cellular damage in light‐exposed areas. Ocular tissues are at risk for photosensitized damage; thus, we investigated the effects on hypericin photophysics by α‐crystallin. We measured the transient absorption spectra and the 1270 nm luminescence of singlet (1Δg) oxygen produced from hypericin in the presence of α‐crystallin. α‐Crystallin complexes hypericin, extending the lifetime of its triplet excited state; the Stern‐Volmer slope is negative, but not linear, after a saturation curve. Damage to the lens protein by hypericin is known to occur via singlet oxygen, which oxidizes methionine, tryptophan and histidine residues. Binding to α‐crystallin does not inhibit singlet oxygen formation by hypericin. α‐Crystallin reacts with singlet oxygen with a rate constant of 1.3 × 108M−1 s−1. Thus, we anticipate that hypericin will be an effective photosensitizer in the lens.
Binding of Metal Ions to Melanin and Their Effects on the Aerobic Reactivity¶
Authors: Hong Lian , Liu Yan , Simon John D. 
Published: July 2010

AbstractThe binding of Mg(II), Ca(II), Zn(II), Cu(II) and Fe(III) to ETDA‐washed Sepia melanin is quantified by inductively coupled plasma mass spectrometry. By monitoring the solution pH change associated with metal uptake, it is concluded that Mg(II), Ca(II) and Zn(II) bind to carboxylic acid groups in melanin, Cu(II) binds to hydroxyl (OH) groups and Fe(III) binds to OH or amine groups. The aerobic reactivity of melanins with different metal contents is analyzed by examining their ability to cause strand breaks in super‐coiled pUC18 DNA. Cu(II)‐ and Fe(III)‐enriched melanins induce the most damage. Hydroxyl radical, *OH, is proposed to be one of the reactive oxygen species responsible.
Phototoxicity in Human Lens Epithelial Cells Promoted by St. John's Wort¶
Authors: He Yu‐Ying , Chignell Colin F. , Miller David S. , Andley Usha P. , Roberts Joan E. 
Published: July 2010

AbstractSt. John's Wort (SJW), an over‐the‐counter antidepressant, contains hypericin, which absorbs light in the UV and visible ranges and is phototoxic to skin. To determine if it also could be phototoxic to the eye, we exposed human lens epithelial cells to 0.1–10 μM hypericin and irradiated them with 4 J/cm2 UV‐A or 0.9 J/cm2 visible light. Neither hypericin exposure alone nor light exposure alone reduced cell viability. In contrast, cells exposed to hypericin in combination with UV‐A or visible light underwent necrosis and apoptosis. The ocular antioxidants lutein and N‐acetyl cysteine did not prevent damage. Thus, ingested SJW is potentially phototoxic to the eye and could contribute to early cataractogenesis. Precautions should be taken to protect the eye from intense sunlight while taking SJW.
Effects of Ultraviolet B Exposure on the Expression of Proliferating Cell Nuclear Antigen in Murine Skin¶
Authors: Moore Julian O. , Palep Sapna R. , Saladl Rao N. , Gao Dayuan , Wang Yongyin , Phelps Robert G. , Lebwohl Mark G. , Wei Huachen 
Published: July 2010

AbstractProliferating cell nuclear antigen (PCNA) is an active nuclear protein involved in DNA replication, recombination and repair. PCNA is found throughout the basal layer in normal skin and in all layers of the epidermis in malignancy. This study evaluates PCNA's expression after acute and chronic UV‐B irradiation. Skh‐1 hairless mice exposed to 1.5 and 4.5 kJ/m2 of UV‐B were sacrificed at 6, 12, 24, 48, 72 and 168 h. Immunohistochemical analysis revealed PCNA expression throughout the basal layer of untreated skin, with diminished expression at 6 h, indicative of immediate UV damage, and evidenced by the observable upregulation in pyrimidine dimer formation early on. Subsequently, PCNA immunoreactivity progressively increased, demonstrating an aberrant upward epidermal migratory pattern in association with chronic exposure. The 4.5 kJ/m2 group exhibited prolonged recovery in staining and also demonstrated this altered migratory pattern with chronic exposure. Progressive reactivation of PCNA expression occurs with repair. PCNA migration to upper layers of the epidermis indicates proliferation and possibly a subsequent increased malignant potential. We conclude that PCNA can serve as a marker of DNA repair and indirectly as an indicator of UV‐B‐induced damage, expression being time dependent and dose related. Specific immunoreactivity patterns and the observable atypia in keratinocytes are relevant in elucidating malignant potentiation.
Ultraviolet‐B Radiation Causes an Upregulation of Survivin in Human Keratinocytes and Mouse Skin¶
Authors: Aziz Moammir Hasan , Ghotra Amaninderapal S. , Shukla Yogeshwer , Ahmad Nihal 
Published: July 2010

AbstractUnderstanding of the mechanism of ultraviolet (UV)‐mediated cutaneous damages is far from complete. The cancer‐specific expression of Survivin, a member of the inhibitor of apoptosis family of proteins, coupled with its importance in inhibiting cell death and in regulating cell division, makes it a target for cancer treatment. This study was designed to investigate the modulation of Survivin during UV response, bothin vitroandin vivo. We used UV‐B‐mediated damages in normal human epidermal keratinocytes (NHEK) cells as anin vitromodel and SKH‐1 hairless mouse model for thein vivostudies. Forin vitrostudies, NHEK were treated with UV‐B and samples were processed at 5, 15, 30 min, 1,3,6,12 and 24 h after treatment. Our data demonstrated that UV‐B exposure (50 mJ/cm2) to NHEK resulted in a significant upregulation in Survivin messenger RNA (mRNA) and protein levels. We also observed that UV‐B exposure to NHEK resulted in significant (1) decrease in Smac/DIABLO and (2) increase in p53. Forin vivostudies, the SKH‐1 hairless mice were subjected to a single exposure of UV‐B (180 mJ/cm2), and samples were processed at 3, 6, 12 and 24 h after UV‐B exposure, UV‐B treatment resulted in a significant increase in protein or mRNA levels (or both) of Survivin, phospho‐Survivin and p53 and a concomitant decrease in Smac/DIABLO in mouse skin. This study demonstrated, for the first time, the involvement of Survivin (and the associated events) in UV‐B responsein vitroandin vivoin experimental models regarded to have relevance to human situations.
A far‐red fluorescent contrast agent to image epidermal growth factor receptor expression
Authors: Hsu Elizabeth R. , Anslyn Eric V. , Dharmawardhane Su , Alizadeh‐Naderi Reza , Aaron Jesse S. , Sokolov Konstantin V. , El‐Naggar Adel K. , Gillenwater Ann , Richards‐Kortum Rebecca R. 
Published: July 2010

AbstractRecent developments in optical technologies have the potential to improve the speed and accuracy of screening and diagnosis of curable precancerous lesions and early cancer, thereby decreasing the costs of detection and management of epithelial malignancies. The development of molecular‐specific contrast agents for markers of early neoplastic transformation could improve the detection and molecular characterization of premalignant lesions. In the oral cavity, epidermal growth factor receptor (EGFR) overexpression has been identified in early stages of premalignant lesions of the oral squamous cell carcinoma; therefore, real‐time assessment of EGFR expression could serve as a biomarker for oral neoplasia. The purpose of our study was to develop a molecular‐specific optical contrast agent targeted against EGFR for in vivo assessment of epithelial neoplasia using a monoclonal antibody and the far‐red fluorescent dye, Alexa Fluor® 660 streptavidin. In addition to demonstrating the specificity of the contrast agent for EGFR in cell lines, we document the ability to achieve penetration through 500 μm thick epithelial layers using multilayer tissue constructs and permeability‐enhancing agents. Finally, using the fluorescence intensity of the contrast agent on fresh oral cavity tissue sections, we were able to distinguish abnormal from normal oral tissue. This contrast agent should have important clinical applications for use in conjunction with fluorescence spectroscopy or imaging (or both) to facilitate tumor detection and demarcation.