bluuebunny/crossref_metadata_2025_split huggingface dataset:
SOLAR UVR EXPOSURES OF THREE GROUPS OF OUTDOOR WORKERS ON THE SUNSHINE COAST, QUEENSLAND
Authors: Gies H. P. , Roy C. R. , Toomey S. , Maclennan R. , Watson M. 
Published: July 2010

AbstractThe solar ultraviolet radiation (UVR) exposures of three groups of outdoor workers, physical education (PE) teachers, ground staff/gardeners and lifeguards were measured using UVR‐sensitive polysulfone (PS) film badges. The exposures all took place on the Sunshine Coast, Queensland over 5 consecutive weekdays in November 1992. For the three groups, the shoulder badges received greater UVR exposures than the chest badges, in agreement with previous studies. The PE teachers received the highest UVR exposures while the lifeguards received the least. One of the 5 days of the study was overcast with some rain showers and UVR doses for this day for all groups were significantly lower than on the other 4 days, however the ratio of exposure to ambient remained relatively constant. All groups had measured UVR exposures in excess of occupational guidelines, indicating that protective measures, including education and behavior modification, which are becoming much more common in occupational situations in Australia, are both timely and necessary.
PHOTODYNAMIC ACTIVITIES and SKIN PHOTOSENSITIVITY OF THE bis(DIMETHYLTHEXYLSILOXY)SILICON 2,3‐NAPHTHALOCYANINE IN MICE
Authors: Brasseur Nicole , Ouellet Rene , Lewis Karina , Potter William R. , Lier Johan E. van 
Published: July 2010

AbstractThe photodynamic therapy (PDT) activity of the bis(dimethylthexylsiloxy)silicon 2,3‐na‐phthalocyanine (SiNc 8) was evaluated against the EMT‐6 tumor implanted intradermally in BALB/c mice. The SiNc 8 was formulated in aqueous emulsions based on Cremophor EL or Solutol HS 15. The formulation was shown to affect plasma clearance and overall pharmacokinetics. Compared to Cremophor, Solutol promoted rapid plasma clearance and high liver retention of the dye, combined with a slight increase of dye tumor concentrations. The PDT action spectrum for tumor response of SiNc 8 in Cremophor (190 mW cm2, 200 J cm2, 24 h postinjection [p.i.] of 1 (jimol kg1) showed a maximum at 780 nm, which corresponds to the absorption maximum of the monomelic dye as well as the in vivo maximum change in the “diffuse optical density” produced by the dye. The extent of tumor necrosis increased with augmented dye and light doses. Regardless of the formulation, at 1 h p.i. of 0.1 μmol kg−! SiNc 8, PDT efficiency (190 mW cm'2, 400 J cm2) was high but accompanied by severe damage to normal tissues, at 24 h PDT resulted in complete tumor regression in 80% of the animals without adverse effects to adjacent tissues, while at 72 h p.i. PDT induced no tumor response with Cremophor and only a partial response with Solutol. At the latter time point, plasma dye clearance was nearly complete while tumor tissue levels remained high, suggesting that tumor response correlates with plasma rather than tumor dye levels. Skin sensitivity of SKhl mice to solar‐simulated radiation was lower with SiNc 8 as compared to Photofrin®. Our data suggest the potential of SiNc 8 as a far‐red absorbing photosensitizer in clinical PDT.
MINIMUM DOSES OF ULTRAVIOLET RADIATION REQUIRED TO INDUCE MURINE SKIN EDEMA and IMMUNOSUPPRESSION ARE DIFFERENT and DEPEND ON THE ULTRAVIOLET EMISSION SPECTRUM OF THE SOURCE*
Authors: Learn Douglas B. , Beasley Donathan G. , Giddens Lori D. , Beard John , Stanfield Joseph W. , Roberts Lee K. 
Published: July 2010

AbstractMany photoimmunological studies have used UV radiation sources that emit nonsolar UV spectral energy and UV doses based on nonimmunological endpoints, e.g. erythema and skin edema. Interpretation of these data has led to misunderstanding when extrapolated to hypothetical effects in humans exposed to solar UV. The purpose of this study was to: (1) establish UV dose response relationships for murine skin edema and immunosuppression, and (2) determine how different UV spectra affect these relationships. Back skin and ear minimum edema doses (MEdD) for Kodacel‐filtered FS20 sunlamp UV (290–400nm) were greater than two‐fold higher than those for unfiltered FS20 sunlamp UV (250–400nm). Xenon arc solar simulator UV (295–400nm) MEdD were > 10‐fold higher than those for unfiltered sunlamp UV. Back skin and ear MEdD differed two‐ to five‐fold between C3H/ HeN, SWR/J and HRA/Skh‐1 mice. The minimum immunosuppression doses (MISD) in C3H mice showed similar UV source spectrum dependence. The solar simulator UV MISD was 5.4‐ and 1.5‐fold higher than for unfiltered and Kodacel‐filtered sunlamp UV MISD, respectively. Furthermore, MISD were from 3‐ to 50‐fold higher than the MEdD for the three UV sources. The UV bioeffectiveness spectra indicated that UVC energy (250–290nm) contributed 12% and 18%, respectively, of the total skin edema and immunosuppression UV energy. These data demonstrate the variability in UV sensitivity among mouse strains, the significant differences between murine MEdD and MISD and how these differences are influenced by nonsolar regions (below 295 nm) of the UV spectrum.
THE VALIDATION OF A NEW VASCULAR DAMAGE ASSAY FOR PHOTODYNAMIC THERAPY AGENTS
Authors: Bellnier David A. , Potter William R. , Vaughan Lurine A. , Sitnik Theresa M. , Parsons John C. , Greco William R. , Whitaker James , Johnson Patricia , Henderson Barbara W. 
Published: July 2010

Abstract—The therapeutic effect of photodynamic therapy (PDT: photodynamic sensitizer + light) is partly due to vascular damage. This report describes a new vascular photodamage assay for PDT agents and a validation of the assay. The method described here quantitates changes in tissue blood perfusion based on the relative amount of injected fluorescein dye in treated and untreated tissues. A specially designed fluorometer uses chopped monochromatic light from an argon laser as a source for exciting fluorescein fluorescence. The fluorescent light emitted from the tissue is collected by a six element fiberoptic array, filtered and delivered to a photodiode detector coupled to a phase‐locked amplifier for conversion to a voltage signal for recording. This arrangement permits a rather simple, inexpensive construction and allows for the simultaneous use of the argon laser by other investigators.The routine assay for characterizing a specific photosensitizer at a standard dose consists of the sequential allocation of eight mice to a set of different light doses designed to span the dose‐response range of fluorescein fluorescence exclusion (measured 8–10 min after fluorescein injection). The assay validation experiment used an anionic photosensitizer, 2‐[l‐hexyloxyethyl]‐2‐devinyl pyropheophorbide‐a at a dose of 0.4 μmol/kg. The parameter estimates (n = 34 mice) from fitting the standard Hill dose‐response model to the data were: median fluorescence exclusion light dose FE50= 275 ± 8.3 J/cm2and Hill sigmoidicity parameter m =−3.66 ± 0.28. Subsets of the full data set randomly selected to simulate a standard eight mice experiment yielded similar parameter estimates. The new assay provides reliable estimates of PDT vascular damage with a frugal sequential experimental design.
Nonlinear Effects and a Cascade of Radical Events Leading to Laser‐Specific Generation of Active Oxygen Species
Authors: Hancock‐Chen Tanya , Scaiano J. C. 
Published: July 2010

ABSTRACTLaser photolysis of benzoyl radical precursors (such as PhCOC[OH]R2) in oxygen‐containing solutions leads to a laser‐specific cascade of oxidative events in which benzoyl peroxyl radicals undergo self‐reaction, ultimately leading to the sequential formation of benzoyloxyl, phenyl and phenyl peroxyl radicals. Thus, photoreactions producing benzoyl (PheO) radicals lead to Ph?O under conditions where benzoyl radicals do not decarbonylate. These reactions require the high‐intensity conditions that can only be achieved under pulsed laser excitation; yet, they do not involve any multiphoton processes. Type I mechanisms of this type may be of importance as new laser‐based therapeutic technologies are developed.
Photophysical Properties and Photobiological Activity of the Furanochromones Visnagin and Khellin
Authors: Borges Marta L. , Latterini Loredana , Elisei Fausto , Silva Palmira F. , Borges Rui , Becker Ralph S. , Maçanita António L. 
Published: July 2010

ABSTRACTThe larger photobiological activity of visnagin (VI) versus khellin (KH) toward several living organisms, including fungi, viruses, yeasts and bacteria, induced a detailed investigation of the photophysical properties of these naturally occurring furanochromones, using laser‐flash‐photolysis, photoacoustic calorimetry and fluorescence (steady‐state and time‐resolved) techniques in solvents with different polarity and content of water, including micelles and vesicles. The results have shown that the magnitude of all the three rate constants out of S1 (radiative, kf; internal conversion, kic and intersystem crossing, kisc) for VI and KH strongly depend on the solvent, namely on its hydrogen bonding ability and polarity. The changes of kf and kisc are due to the solvent‐assisted mixing and/or inversion of the two first singlet excited states (1n,π* and 1π,π*), while kic increases with a decrease of the So–S1 energy gap. As a consequence, the quantum yield of triplet formation (φT) strongly decreases from values of ˜0.8 in dioxane to < 0.05 in water for both compounds. The magnitude of solvent polarity/hydrogen bonding ability required, at which the state order is inverted and φT starts to decrease, is greater for VI than for KH and consequently φT (VI) > φT (KH) over a broad range of water content including that appropriate to the environment of the compounds in a living system. These facts account for the larger photobiological activity of VI with respect to KH, regarding both the fungus Fusarium culmorum L. and the wild strain of Escherichia coli, studied by us.
Photochemistry of Flavins in Micelles: Specific Effects of Anionic Surfactants on the Monomerization of Thymine Cyclobutane Dimers Photosensitized by Tetra‐O‐acyl Riboflavins*
Authors: Yasuda Masahide , Nishinaka Yoshimasa , Nakazono Takumi , Hamasaki Takeshi , Nakamura Nobuya , Shiragami Tsutomu , Pac Chyongjin , Shima Kensuke 
Published: July 2010

ABSTRACTIt was found that tetra‐o‐acyl riboflavins efficiently photosensitize the monomerization of the cis, syn‐cyclobutane dimers of 1,3‐dimethylthymine and 1,3‐dimethyluracil in aqueous solution in the presence of such anionic surfactants as sodium dodecyl sulfate and sodium hexadecyl sulfate at concentrations higher than their critical micelle concentration, while little monomerization of the dimers was photosensitized by the flavins in the absence of the surfactants and even in the presence of cationic and nonionic surfactants.
Urocanic Acid Does not Photobind to DNA in Mice Irradiated with Immunosuppressive Doses of UVB*
Authors: Ijland Steven A. J. , Noonan Frances P. , Ceryak Susan , Steenvoorden David P. T. , Bouscarel Bernard , Hug Dan , Beijersbergen van Henegouwen Gerard M. J. , De Fabot† Edward C. 
Published: July 2010

ABSTRACTUltraviolet B (UVB, 290–320 nm) radiation initiates in vivo a dose‐ and wavelength‐dependent down regulation of cell‐mediated immunity. An action spectrum for UV‐induced immunosuppression indicated that the photoreceptor for this effect is urocanic acid (UCA), which undergoes a trans to cis isomerization in the stratum corneum on UV exposure. An accumulation of evidence has supported this conclusion. However, evidence has a/so been presented that formation of thymine dimers in DNA is responsible for initiation of UV‐induced immunosuppression. Because photobinding of UCA to DNA in vitro forming cyclobutane‐type adducts has been shown, we sought to resolve this dilemma by investigating if UCA photobinds to DNA in vivo. The [14C]cis‐UCA, [14C]trans‐UCA or [3H]8‐MOP (8‐methoxypsoralen) was applied topically to BALB/c mice that were then irradiated with a dose of UV previously shown to cause systemic suppression of contact hypersensitivity. The DNA was prepared from epidermal cells by phenol extraction immediately after in vivo irradiation and bound radioactivity determined. Although photobinding of [3H]8‐MOP was readily demonstrable under these conditions (0.9 nmol/mg DNA), no significant binding of either isomer of UCA to DNA (between 1.2 × 10−3 and 2.1 × 10−3 ng/mg DNA) could be detected. Uptake studies in keratinocytes prepared from epidermis of untreated animals indicated that [3H]8‐MOP was taken up with a rate constant of 4.2 × 10−3 pmol/s/mg protein/μmol/L. In contrast, uptake of [14C]cis‐UCA was not statistically significant from zero and uptake of [14C]trans‐UCA was negligible (0.8 × 10−3± 0.08 × 10 3 pmol/s/mg protein/μmol/L). There was no significant difference between uptake of UCA isomers but uptake of [3H]8‐MOP was significantly greater than that of either UCA isomer (P < 0.01). These studies indicate that the photobinding of UCA to DNA does not play a role in UV‐induced immunosuppression.
p53 Mutations in Hairless SKH‐hr1 Mouse Skin Tumors Induced by a Solar Simulator
Authors: Ananthaswamy Honnavara N. , Fourtanier Anny , Evans Randall L. , Tison Sylvie , Medaisko Chantal , Ullrich Stephen E. , Kripke Margaret L. 
Published: July 2010

ABSTRACTIn this study, we investigated whether the spectrum of p53 mutations in skin tumors induced in hairless SKH‐hr1 mice by a solar simulator (290–400 nm) are similar to those found in skin tumors induced in C3H mice by UV radiation from unfiltered (250–400 nm) and Kodacelfiltered (290–400 nm) FS40 sunlamps. Analysis of tumor DNA for p53 mutations revealed that 14 of 16 (87.5%) SkH‐hr1 skin tumors induced by the solar simulator contained mutations. Single C → T transitions at dipyrimidine sequences located on the nontranscribed DNA strand were the most predominant type of p53 mutation. Remarkably, 52% of all p53 mutations in solar simulator‐induced SKH‐hr1 skin tumors occurred at codon 270, which is also a hotspot in C3H skin tumors induced by unfiltered and Kodacel‐filtered FS40 sunlamps. However, T → G transversions, which are hallmarks of UVA‐induced mutations, were not detected in any of the solar simulator‐induced skin tumors analyzed. These results demonstrate that the p53 mutation spectra seen in solar simulator‐induced SKH‐hr1 skin tumors are similar to those present in unfiltered and Kodacel‐filtered FS40 sunlamp‐induced C3H skin tumors. In addition, our data indicate that the UVA present in solar simulator radiation does not play a role in the induction of p53 mutations that contribute to skin cancer development.
The Structure of the Aggregate Form of Bacteriochlorophyll c Showing the Qy Absorption above 740 nm as Determined by the Ring‐current Effects on 1H and 13C Nuclei and by 1H–1H Intermolecular NOE Correlations
Authors: Mizoguchi Tadashi , Sakamoto Shun , Koyama Yasushi , Ogura Kenji , Inagaki Fuyuhiko 
Published: July 2010

ABSTRACT 13C‐enriched bacteriochlorophyll c (S[I, E] BChl cF) was suspended in a 1:3 mixture of methylene chloride and carbon tetrachloride to form an aggregate showing the Qy absorption above 740 nm; changes in the 13C chemical shifts were traced when methanol was titrated to dissolve the aggregate, and then, the changes were correlated to the ring‐current effects due to the neighboring macrocycles in the aggregate. A pair of aggregate structures has been proposed based on the ring‐current effects on both 1H and 13C nuclei; the monomeric units are stacked together to form an inclined column with different sliding directions, in which the y‐axis of the molecule is parallel to the long axis of the column. In order to confirm this pair of models, the ring‐current effects on the 1H and 13C nuclei were calculated based on both the magnetic‐dipole and the loop‐current approximations. Further, an application of three‐dimensional F1 13C‐edited F3 13C‐filtered heteronuclear single‐quantum correlation‐nuclear Overhauser effect spectroscopy to the above aggregate consisting of a 1:1 mixture of 13C‐labeled and unlabeled BChl c succeeded in detecting selectively the 1H–1H intermolecular nuclear Overhauser effect correlations, which established the coexistence of the above pair of stacked structures in the aggregate.
Protoporphyrin IX Fluorescence Induced in Basal Cell Carcinoma by Oral δ‐Aminolevulinic Acid*
Authors: Tope Whitney D. , Ross E. Victor , Kollias Nikiforos , Martin Alex , Gillies Robert , Anderson R. Rox 
Published: July 2010

ABSTRACTLimited depth of penetration significantly limits photodynamic therapy of nodular basal cell carcinoma (BCC) using topical δ(5)‐aminolevulinic acid (ALA). To demonstrate safety and efficacy of orally administered ALA in inducing endogenous protoporphyrin IX (PpIX) production in BCC, 13 patients with BCC ingested ALA in a dose‐escalation protocol. All dose ranges (10, 20 or 40 mg/kg single doses) resulted in formation of PpIX in human skin and BCC, measurable by in vivo fluorescence spectrophotometry. The PpIX fluorescence peaked in tumors before normal adjacent skin from 1 to 3 h after ALA ingestion. Gross fluorescence imaging of ex vivo specimens revealed greater PpIX fluorescence in tumor than normal skin only at the 40 mg/kg dose. Fluorescence microscopy confirmed this finding by showing distinct, full‐thickness PpIX fluorescence in all subtypes of BCC only after ALA given at 40 mg/kg. Side effects were dose dependent and self limited. Photosensitivity lasting less than 24 h and nausea coinciding with peak skin PpIX fluorescence occurred at 20 and 40 mg/kg doses. After 40 mg/kg ALA, serum hepatic enzyme levels rose to a maximum within 24 h, then resolved over 1–3 weeks. Transient bilirubinuria occurred in two patients.
Contribution of the cAMP‐Dependent Signal Pathway to Circadian Synchrony of Motility and Resting Membrane Potential in Paramecium
Authors: Hasegawa Kenji , Tsukahara Yasuo , Ishizaki Shigeo , Shimamoto Masakazu , Nakamura Takeshi , Sohma Masaki , Sato Toshiro 
Published: July 2010

ABSTRACTIt is known that the ciliated protozoan Paramecium multimicronucleatum has synchronized circadian rhythms of motility, resting membrane potential and cyclic adenosine 3′,5′‐monophosphate (cAMP) and cyclic guanosine 3′,5′‐monophosphate (cGMP) concentrations. The present study shows that (1) extracellularly added 4 mM tetraethylammonium (TEA)+ (a K+ channel blocker) almost completely abolishes the diurnal oscillation of intracellular cAMP concentrations; (2) even 32 mM TEA+ fails to abolish the circadian motility rhythm; but (3) the motility rhythm is highly damped when 4 mM TEA+ and 100 μM CdCl2 (a Ca2+ channel blocker) are added simultaneously. A cAMP analogue (N6‐monobutyryl‐cAMP) added extracellularly accelerates swimming velocity. Both a K+ channel blocker (e.g. TEA+) and an inhibitor (trifluoperazine) of adenylate cyclase (AC) suppress cAMP formation, supporting the hypothesis that AC in Paramecium has dual functions, as a K+ channel and as an enzyme for cAMP formation. It is hypothesized that the circadian synchrony is due to circadian fluctuations of AC causing separate circadian changes both in ciliary motion and membrane potential through a cAMP‐dependent signal pathway that forms a sophisticated network of second messengers to govern the synchrony together with Ca2+‐ and cGMP‐dependent pathways in a manner antiphasic and/or complementary to one another.
Unrepaired Cyclobutane Pyrimidine Dimers Do Not Prevent Proliferation of UV‐B‐irradiated Cultured Human Fibroblasts¶
Authors: Courdavault Sophie , Baudouin Caroline , Sauvaigo Sylvie , Mouret Stéphane , Candéias Serge , Charveron Marie , Favier Alain , Cadet Jean , Douki Thierry 
Published: July 2010

ABSTRACTMutagenic and carcinogenic UV‐B radiation is known to damage DNA mostly through the formation of bipyrimidine photoproducts, including cyclobutane dimers (CPD) and (6‐4) photoproducts ((6‐4) PP). Using high‐performance liquid chromatography coupled to tendem mass spectrometry, we investigated the formation and repair of thymine‐thymine (TT) and thymine‐cytosine (TC) CPD and (6‐4) PP in the DNA of cultured human dermal fibroblasts. A major observation was that the rate of repair of the photoproducts did not depend on the identity of the modified phyrimidines. In addition, removal of CPD was found to significantly decrease with increasing applied UV‐B dose, whereas (6‐4) PP were efficiently repaired within less than 24 h, irrespective of the dose. As a result, a relatively large amount of CPD remained in the genome 48 h after the irradiation. Because the overall applied doses (<500 J m−2) were chose to induce moderate cytotoxicity, fibroblasts could recover their proliferation capacities after transitory cell cycle arrest, as shown by 5‐bromo‐2′‐deoxyuridine (BrdUrd) incorporation and flow cytometry analysis. It could thus be concluded that UV‐B‐irradiated cultured primary human fibroblasts normally proliferate 48 h after irradiation despite the presence of high levels of CPD in their genome. These observations emphasize the role of CPD in the mutagenic effects of UV‐B.
Comparative Study of Photodynamic Properties of 13, 15‐N‐cycloimide Derivatives of chlorin p6¶
Authors: Feofanov Alexei , Sharonov George , Grichine Alexei , Karmakova Tatyana , Pljutinskaya Anna , Lebedeva Victoria , Ruziyev Ramezes , Yakubovskaya Raisa , Mironov Andrei , Refregier Matthieu , Maurizot Jean‐claude , Vigny Paul 
Published: July 2010

ABSTRACTComparative study of 13,15‐[N‐(2‐hydroxyethyl)]cycloimide chlorin p6 (2), 13,15‐(N‐acetoxy)cycloimide chlorin p6 (3), 13,15‐(N‐hydroxy)cycloimide chlorin p6 methyl ester (4) and 13,15‐(N‐methoxy)cycloimide chlorin p6 methyl ester (5) together with the previously investigated 13,15‐[N‐(3‐hydroxypropyl)]cycloimide chlorin p6 (1) was performed. The dependence of the key photodynamic properties of 1–5 on the introduced substituents was analyzed. The photoinduced cell‐killing activity of 4 is 100‐ and 280‐fold higher than that of chlorin p6 and Photogem, respectively, as estimated on A549 human lung adenocarcinoma cells. The activity is reduced eight times in the order 4 > 5 > 1 > 2 > 3. The intracellular accumulation of 1–5 occurs in cytoplasm in a monomeric form bound to the lipids of cellular membranes. This form of 1,2,3, 4 and 5 is characterized by the high quantum yield of singlet oxygen generation, which depends on the introduced substituents, 0.66, 0.59, 0.35, 0.51 and 0.73, respectively. The photostability is two‐fold less for 1 and four‐fold less for 2, 3 and 5 than for 4. The rates of cellular uptake and efflux of 1–5 vary widely, thus providing the way to optimize the pharmacological properties of the photosensitizer (PS) using the respective substituents. Modifying the substituents, 1–5 were targeted to different cellular organelles. The enhanced accumulation in the Golgi apparatus and mitochondria complemented with diffuse staining of intracellular membranous structures is a property of 1–4. Compound 5 accumulates selectively in the lipid droplets and stains weakly perinuclear structures. Temperature‐sensitive mechanisms of transport are responsible for the 1–4 uptake. Diffusion can play a role in the internalization of 5 but not of 1–4. Endocytosis via caveolae, clathrin‐dependent and adenosine triphosphate‐dependent pathways are not noticeably involved in the 1–5 internalization. Independently from their intracellular localization 1,4 and 5 are highly efficient near‐IR PS, which induce predominantly an apoptotic type of cell death under conditions providing ca 50% level of phototoxicity and necrosis at the 100% level of phototoxicity.