bluuebunny/crossref_metadata_2025_split huggingface dataset:
THE EFFECTS OF ULTRAVIOLET LIGHT ON HOST CELL REACTIVATION AND PLAQUE SIZE OF Herpes simplex VIRUS TYPE I IN C3H/lOT1/2 MOUSE CELLS
Authors: Montes Joseph G. , Taylor William D. 
Published: January 2008

Abstract—Herpes simplex virus — type 1 (HSV‐I) plaque‐forming ability and plaque size were measured on C3H/1OT1/2 cell monolayers as functions of pretreatment dose with UV light at different times before inoculation with virus, in order to determine if UV‐enhanced reactivation (ER) of UV‐irradiated virus. as well as associated phenomena, could be obtained in this cell system. The number of virus plaques observed (i.e. the capacity of the cells to support virus growth) and the size of the plaques were found to increase substantially with pretreatment of the cells with UV light. However, no significant ER was observed. Therefore, the mechanisms responsible for the increases in plaque size and cell capacity seem to be independent of those responsible for ER. In work by others. C3H/l0T1/2 cells have hcen transformed by UV light at doses similar to those used in this study; the absence of ER of UV‐irradiated virus in this study indicates that the mechanism underlying ER is not required for transformation.
AN ACTION SPECTRUM FOR BLUE AND NEAR ULTRAVIOLET IN ACTIVATION OF Propionibacterium acnes; WITH EMPHASIS ON A POSSIBLE PORPHYRIN PHOTOSENSITIZATION
Authors: Kjeldstad Berit , Johnsson Anders 
Published: January 2008

Abstract—Propionibacterium acnes (P. acnes), grown on Eagles medium with different pH. were irradiated with monochromatic light in the range 320 to 440 nm. Different pH leads to different porphyrin concentrations in the cells. The light sensitivity of the bacteria was estimated from the reduction in their ability to form colonies after radiation. The sensitivity was highest for the lowest wavelength (320 nm). and decreased continuously with increasing wavelength up to 380 nm. In the region between 380 and 440 nm there was a second maximum (at 415 nm) which corresponds to the maximum absorption ol the fluorescing porphyrins in P. acnes. The sensitivity to 415 nm light was found to be dependent on the endogenous porphyrin concentration in the cells. while the sensitivity to 320 nm radiation was independent of the amount of porphyrin present. These results indicate that porphyrins produced by the bacteria are important for the light sensitivity of these bacteria.
DECAY KINETICS OF THE TRIPLET EXCITED STATE OF LUMIFLAVIN
Authors: Naman S. A. , Tegnér L. 
Published: January 2008

Abstract— The rate of decay of the triplet state of lumiflavin in deaerated phosphate buffer at pH 6.9, has been studied using the flash photolysis technique, at various concentrations and flash energies. The decay of the transient appears as a mixture of first and second order processes, the relative importance of which depends on the experimental conditions.The following competitive reactions have been found to explain the course of the reaction of the triplet excited state of lumiflavin.
LOSS OF PHOTOREVERSIBILITY OF SUNBURN CELL INDUCTION IN Monodelphis domestica
Authors: Ley Ronald D. , Applegate Lee A. 
Published: January 2008

AbstractExposure of the South American opossum, Monodelphis domestica, to ultraviolet radiation (UVR) resulted in the formation of sunburn cells (SBCs) in the epidermis. If, however, the UVR was immediately followed by an exposure to photoreactivating light, which reversed ∼ 95% of the UVR‐induced pyrrolidine dimers in epidermal DNA, the appearance of SBCs was suppressed by ∼ 90%. Delaying the photoreactivation (PR) treatment resulted in a progressive loss with time in the capacity of the PR treatment to suppress SBC induction. PR treatment administered 12 h after UVR exposure resulted in only an ∼ 11% suppression of SBC formation even though ∼ 97% of the remaining pyrimidine dimers were repaired by the PR exposure.
MICELLAR EFFECT ON THE FLUORESCENCE QUENCHING OF INDOLIC COMPOUNDS BY AMINOACIDS
Authors: Bertolotti S. G. , Bohorquez M. DEL V. , Cosa J. J. , Garciaand N. A. , Previtali C. M. 
Published: January 2008

AbstractThe effect of anionic and cationic micelles on the fluorescence quenching of indolic compounds by aliphatic aminoacids has been studied. Sodium dodecyl sulfate (SDS) micelles increase the quenching efficiency of glycine, alanine, valine and leucines up to a factor of two. On the other hand, cetyltrimethyl ammonium (CTAB and CTAC) micelles reduce the quenching. For sulfur containing aminoacids (methionine and cysteine) both SDS and CTAC reduce the quenching. The inhibitory effect is larger for CTAC. Linear Stern‐Volmer plots were obtained and in the case of SDS lifetime measurements indicate that the quenching is of dynamic nature.The results were interpreted by a model which assumes that aminoacids can interact with SDS micelles. Partition constants of the order of unity were estimated. For CTAC the aminoacids are not able to interact with the micelles.
INDUCTION OF CHLOROPLAST MOVEMENT IN THE ALGA Mougeotia BY POLARIZED NANOSECOND DYE‐LASER PULSES*†
Authors: Scheuerlein R. , Braslavsky S. E. 
Published: January 2008

Chloroplast movement of white‐light treated alga Mougeotia was induced by 15‐ns dye‐laser pulses (620‐690 nm). A single pulse, polarized perpendicular to the cell axis, does not induce a significant response, although full response can be obtained when the same fluence is applied during a 30‐s irradiation. However, for 620 and 660 nm perpendicularly polarized flash irradiation results in a significant response, if the total fluence is given by 2 consecutive flashes with 2‐s dark interval (double‐flash effect), and full response can be obtained by poly‐flash induction. Flashes of 690 nm in no case induce a response. Similar to the case of lettuce‐seed germination (Scheuerlein and Braslavsky, 1985), the establishment of a photochromic system between Pr and the very early intermediates (= lumi‐R) during the 15‐ns laser pulse can explain the results. At 690 nm, the photochromic system is shifted more extensively to Pr than at shorter wavelengths; thus, Pfr formation is strongly diminished. At shorter wavelengths (620 and 660 nm) the inhibition of Pfr formation by the existence of this photochromic system is smaller. The results are compatible with parallel dipole moments of the chromophores in Pr and in the first intermediates.A smaller but still significant response is obtained for repeated pulses of 660‐nm light, polarized parallel to the cell axis. These results are explained by a gradient in light sensitivity around the cell axis (induced by the white‐light pretreatment) and an increasing Plr concentration, established around the cell axis, as a function of the number of pulses.
PHOTODYNAMIC THERAPY OF MALIGNANT PRIMARY BRAIN TUMOURS: CLINICAL EFFECTS, POSTOPERATIVE ICP, and LIGHT PENETRATION OF THE BRAIN
Authors: Muller Paul J. , Wilson Brian C. 
Published: January 2008

Abstract We are reporting our experience with intraoperative PDT in 32 patients with malignant supratentorial gliomas; in 19 cases the tumour was recurrent. There were 20 males and 12 females with an age range of 17‐73 (mean = 45) yr. The first 8 patients in this series received HpD (Photofrin I) and the next 24 received DHE (Photofrin II). A photo‐illuminating device, of the author's design, was coupled to an argon dye pump laser in order to deliver light at 630 nm to a tumour cavity created by radical tumour resection and/or tumour cyst drainage. The total light energy delivered ranged from 440 to 3888 J and the light energy density ranged from 8 to 68 J cm−2.There were two post‐operative deaths as the consequence of hematoma accumulation in an extensive tumour resection cavity. In two patients neurological function was worse post‐operatively and did not recover. Post‐operative cerebral edema was pronounced in eight cases and required emergency craniotomy in two patients (the histology from both showed hemorrhagic necrosis of residual tumour). We have fashioned continuous post‐operative ICP measurements in the last 15 patients treated with PDT and compared the values to those obtained from cases with malignant gliomas who did not have PDT; the mean ICP was significantly greater in the PDT group. Four patients developed wound infections; two of these required surgical treatment. Four patients, two of whom were hemiparetic, developed deep vein thrombosis and required anticoagulant therapy. There were no adverse systemic reactions to the administration of either photosensitizer and only 3 skin photosensitivity reactions.Follow up has ranged from 1 to 26 months at the time of writing; 38% were still alive; in the interval between PDT and death, the deaths per observation year was 1.11 for the whole group and 1.00 when the two post‐operative deaths are excluded. In the interval between first diagnosis and death the rate was 0.45 deaths per observation year. Photodynamic therapy of malignant brain tumours using surface or cavitary photo‐illumination can be carried out with acceptable risk.In eight patients we determined the penetration depth of light in brain tissue in vivo by reading the detected light flux from a fiber passed radially into the brain towards the centre of the irradiation volume. The optical fiber consisted of a single 400 μ.m, cleaved fiber fixed in a 17‐gauge biopsy needle coupled to a photometer. The light penetration depth ranged from 0.8 to 4.9. The mean PD values in the‘tumour’group and the‘brain’group was 2.9 ± 1.5 and 1.5 ± 0.43, respectively. We attribute this significant difference to the differences in the absorption and scattering properties of brain and tumour.
THE EFFECT OF SUBSTITUENTS ON PHTHALOCYANINE PHOTOCYTOTOXICITY
Authors: Rosenthal I. , Ben‐Hur E. , Greenberg S. , Concepcion‐Lam A. , Drew D. M. , Leznoff C. C. 
Published: January 2008

AbstractPhthalocyanine (Pc) dyes are a class of photosensitizers that are being considered for use in the photodynamic therapy of cancer. A final choice for the most useful drug demands phototoxicity screening of various structurally related Pc dyes, such as those with different substituents at the peripheral benzene rings. Using the colony forming ability of Chinese hamster cells as an endpoint, the photobiological activity for ZnPc was found to be the highest for the unsubstituted compound, followed in decreasing order by the 2,9,16,23‐tetrahydroxy‐, 2,9,16,23‐tetrasulfonated‐, and 2,9,16,23‐tetraneopentoxy‐Pc derivatives. This effect could be correlated with the uptake rate of the respective Pc derivatives by the cells, but it is unrelated to the apparent lipophilicity of these compounds, or, alternatively, to their ability to photogenerate singlet oxygen. The first synthesis of a metal‐free tetrahydroxy Pc is described.
CAROTENE AND CYTOCHROME c DEPENDENT MITOTIC RECOMBINATION AND KILLING IN RESPONSE TO VISIBLE LIGHT AND UV‐C IN THE SMUT FUNGUS Ustilago Violacea
Authors: Kovacs Adrienne M. , Rossing William , III Oscar H. Will , Ruddat Manfred 
Published: January 2008

Abstract— The carotene (carotenoid hydrocarbons) and cytochrome c compositions for the phlph+ pink diploid strain of Ustilago violacea and three newly developed color variants, white (w), orange (o), and yellow (y) were quantitatively determined using high‐performance liquid chromatography of lipid extracts and difference spectroscopy of alkali extracts. In addition, the effect of high‐intensity incandescent and far UV (UV‐C) radiation on survival and mitotic recombination in all four phlph+ strains were studied. The phlph+w and phlph+y strains contained relatively small amounts of cytochrome c; however, the phlph+y strain accumulated β‐carotene while in the phlph+w strain only the colorless carotene phytoene was found. The phlph+w was very sensitive to incandescent radiation, with complete killing by 90 min of exposure. The induction of mitotic recombination in the phlph+w strain was inversely proportional to the level of survival, with 96% induction by 90 min of exposure. The β‐carotene‐accumulating phlph+y strain was considerably more resistant to photokilling, and exhibited induction of mitotic recombination at a lower level. Similar results were observed with these strains in response to UV‐C. The phlph+y strain was significantly more resistant to UV‐C killing than the phlph+w strain and it also exhibited lower induced levels of mitotic recombination.The phlph+o and phlph+ pink strains accumulated over 10 times the cytochrome c as the phlph+w or phlph+y strains. The phlph+o strain accumulated β‐carotene at the level of the phlph* y strain, but the phlph+ pink strain contained only about one‐tenth as much β‐carotene. The phlph+ o and phi ph+ pink strains exhibited sensitivity to visible radiation that was intermediate to the phlph+y and phlph+w strains. Mitotic recombination induction by visible radiation in the orange and pink strains was slightly less than that in the phlph+w strain. In response to UV‐C, the phlph+o and phlph+ pink strains had survival and mitotic recombination induction characteristics that were similar to the phlph+w strain.
A HIGH RESOLUTION FLUORESCENCE DECAY AND DEPOLARIZATION STUDY OF HUMAN PLASMA APOLIPOPROTEINS
Authors: Chang Mary C. , Fleming Graham R. , Scanu Angelo M. , Yang Nien‐chuC 
Published: January 2008

Abstract— Human plasma apolipoprotein A‐I (apoA‐I) and apolipoprotein C‐I (apoC‐I) were investigated by time‐resolved fluorescence decay and depolarization. The tryptophyl fluorescence of apoA‐I undergoes a double‐exponential decay with lifetimes of 1.07 and 3.43 ns which remain unchanged over the range of apoA‐I concentration studied.The time‐resolved fluorescence of both native and denatured forms of apoC‐I exhibits an unusual tryptophyl fluorescence decay that was best fit to a triexponential function with lifetimes at 3.7 ± 0.2, 1.1 ± 0.1 and 0.1 ns at 2°C. The native and denatured forms of apoC‐I had rotational correlation times of 1.42 and 1.19 ns at 20°C respectively. A shorter rotational correlation time associated with the internal tryptophan motions was not observed or resolved.The decay of tryptophyl fluorescence in apoC‐I/DPPC/cholesterol complex at 20°C is also triexponential with lifetimes at 4.94, 1.28 and 0.21 ns, which are longer than those of the uncomplexed forms. Two rotational correlation times of 28.32 and 0.59 ns at 20°C were resolved by fluorescence depolarization measurements. The long rotational time remained constant with temperatures above 30°C. Also, the temperature dependence of the order parameter, S2, resembled a lipid phase transition curve with a transition midpoint at 38°C. The tryptophan and thus apoC‐I are found to be affected by the bulk changes in the lipid.
SYNTHETIC PORPHYRINS AT INTERFACES; PHOTOSENSITIZATION AND RELATED REACTIONS OF ATROPISOMERS OF o‐SUBSTITUTED TETRAPHENYLPORPHINE DERIVATIVES IN FILMS, REVERSED MICELLES AND MEMBRANES †
Authors: Collins‐Gold L. C. , Barber D. C. , Hagan W. J. , Gibson S. L. , Hilf R. , Whitten D.G. 
Published: January 2008

Abstract— Previous studies from our laboratories and elsewhere have shown that amides between fatty acids and the synthetic α, α, α, α ‐tetra (o‐aminophenyl)‐porphyrins exhibit good surfactant properties which facilitate their incorporation into structured assemblies characterized by hydrophobic‐hydrophilic compartmentalization. This paper will focus on a number of aspects of our studies of these porphyrins at different interfaces.The α, α, α, α (4,0) isomers are readily incorporated into Langmuir‐Blodgett films as either free base or metal complexes. Studies of assemblies containing free base and palladium (II) complexes have been carried out in which the porphyrin is irradiated in the presence of oxygen and nonexcited but oxidizable substrates. Much of the reactivity observed can be attributed to 1O2* generation. These studies reveal the migration range and reactivity of activated oxygen in a structure related to biomem‐branes.Several of these synthetic porphyrins have also been examined in cell suspensions and in synthetic reversed micelle solutions. Studies in the former have shown that the porphyrins can mediate the photoinactivation of several enzymes located inside and within the mitochondrial membrane in tumor cells extracted from rats. They are found to compare favorably to hematoporphyrin derivative in effectiveness.Studies of the same porphyrins in their reactivity towards copper ion incorporation in anionic reversed micelles indicate striking rate differences which can be interpreted in part to structural variations between the porphyrins as well as to their orientation at the hydrophobic‐hydrophilic interface.
INHIBITORY EFFECTS OF ETHANOL ON THE PHOTODYNAMIC CELL INACTIVATION AND PETITE INDUCTION BY EUFLAVINE IN YEAST, Saccharomyces cerevisiae
Authors: Tsuchiya M. , Iwamoto Y. , Masuzawa T. , Shimizu T. , Morita T. , Yanagihara Y. 
Published: January 2008

Abstract— Effects of active oxygen scavengers on cell inactivation and petite induction of yeast by the photodynamic action of euflavine were examined. Histidine, sodium azide, 1,3‐diphenyl‐isobenzofuran and p‐carotene, which are singlet oxygen scavengers, inhibited photodynamic cell killing. Histidine and sodium azide inhibited petite induction, too. These results suggested that photobiological effects of euflavine are induced via singlet oxygen‐mediated Type II reaction process. In this work, however, we found that ethanol, which is reported to be a hydroxyl radical scavenger, notably inhibited photodynamic cell inactivation and petite induction by euflavine. Inhibition of petite induction was increased with increasing concentration of ethanol. Decrease of absorbance of euflavine by irradiation was also inhibited by the addition of ethanol.These results suggested that ethanol possibly acts as a singlet oxygen scavenger.
THE CONTROL OF METABOLISM BY BLUE LIGHT IN Acetabularia mediterranea—I. LIGHT DEPENDENCY AND EVIDENCE FOR POST‐TRANSCRIPTIONAL CONTROL OF UDPG PYROPHOSPHORYLASE AND PYRUVATE KINASE
Authors: Nickl Bernhard , Maass Ingrid , Schmid Rainer 
Published: January 2008

Abstract— After a preculture in white light, Acetabularia mediterranea Lamouroux (=A. acetabulum (L.) Silva) was irradiated with either continuous red or blue light. In crude extracts, the specific activities of UDPG pyrophosphorylase(uridine–5′‐triphosphate: glucose 1‐phosphate uridylyltransfer‐ase EC 2.7.7.9) and pyruvate kinase(adenosine–5′‐triphosphate: pyruvate phosphotransferase EC 2.7.1.40) varied as a result of the different light qualities. In red light activities decreased to 40% and 60%, respectively, within 3 weeks of irradiation, while under blue light, if not preceded by a red irradiation, the activities remained unchanged. After prolonged red light, high enzyme activities were restored by blue light with a relatively rapid time course (3 to 4 days for completion) compared with the decrease in red light. A fluence‐response curve for the activation of UDPG pyrophosphorylase showed two phases with different sensitivities for blue light.The blue light‐mediated increase in the activities of both enzymes was unaffected when the cell nucleus was removed before the beginning of the blue irradiation. The increase was inhibited by cycloheximide but not by chloramphenicol. Thus, functional cytosolic translation but not de novo transcription products are presumed to be required for the increase in specific enzyme activities in vivo.
MEASUREMENTS OF SOLAR MIDDLE ULTRAVIOLET RADIATION IN A DESERT ENVIRONMENT
Authors: Kollias N. , Baqer A. H. , Sadiq I. 
Published: January 2008

Abstract— In this study measurements are reported that were carried out between August 1983 and December 1985 on the solar middle ultraviolet radiation (UVB‐280‐320 nm) in Kuwait (29.5°N). These measurements are based primarily on polysulfone film detectors. Comparative measurements were also made on a Robertson‐Berger meter and a spectroradiometer. The results reported include the daily variation of the solar UVB between 11:30 a.m. and 12:00 noon over the year, the diurnal variation, as well as the amount of UVB as a function of the receiving angle with the horizontal.Based on these data the polysulfone films were found to be reliable and inexpensive detectors, giving results similar to those of the R‐B meter. The diurnal variation of the solar UVB was found to vary as sin2q, where q is an angle that corresponds to the time since sunrise compared to the sunrise‐sunset interval times 180. An empirical equation is developed that gives the maximum UVB as a function of the time of day and day of year. A correlation is determined of the polysulfone readings with the spectroradiometric and the R‐B meter measurements. The solar insolation was found to be independent of the receiving angle with the horizontal in the winter months and develops into a cosine dependence in the summer months.
ENHANCEMENT OF UV‐INDUCED SKIN CARCINOGENESIS BY AZATHIOPRINE: ROLE OF PHOTOCHEMICAL SENSITISATION
Authors: KELLY GRAHAM E. , MEIKLE WILLIAM D. , MOORE DOUGLAS E. 
Published: January 2008

Abstract The phototoxicity of various drugs (chlorpromazine (CPZ), metronidazole (MET), 8‐methoxypsoralen (8‐MOP), azathioprine (AZA) and the azathioprine metabolites, 6‐mercaptopurine (6‐MP), methylnitrothio‐imidazole (MNTI), methylnitroimidazole (MNI)) was determined in hairless (Skh‐hrl) mice exposed to a light source with broad emission (290–700 nm). Chlorpromazine, MET, 8‐MOP, AZA, MNI and 6‐MP were phototoxic, as determined by the oedematous response of skin, at doses comparable to those used clinically.The effects of long‐term drug therapy and UV radiation on skin carcinogenesis were then determined. Chlorpromazine and MET, and to a lesser extent AZA, MNTI and 6‐MP, enhanced photocarcinogen‐esis. In each case, both the tumour yield and the proportion of malignant:benign skin tumours were increased. The results of this study imply that prolonged treatment of mice with low‐level phototoxins predisposes to photocarcinogenesis.
INFLUENCE OF DIETARY MENHADEN OIL UPON CARCINOGENESIS AND VARIOUS CUTANEOUS REspONSES TO ULTRAVIOLET RADIATION*
Authors: ORENGO IDA F. , BLACK HOMER S. , KETTLER ANNE H. , WOLF JOHN E. 
Published: January 2008

Abstract Recent reports suggest that eicosapentaenoic acid (EPA) inhibits growth of transplanted tumors and the formation of various chemically induced cancers in animals. Menhaden oil is a source of polyunsaturated lipid with a high content of EPA, an omega‐3 fatty acid. We sought to explore the effects of menhaden oil on photocarcinogenesis by employing the hairless mouse/UV‐carcinogenesis model. Five groups of 40 SKH‐Hr‐1 mice received (a) a semipurined equicaloric diet containing either 0.75% corn oil, 4% corn oil. 4% menhaden oil or 12% menhaden oil and (b) an escalating regimen of UV radiation to a cumulative dose of 70 J/cm2. Additional animals were employed to further examine the role of menhaden oil in acute cutaneous responses to UV, i.e., erythema, edema, and ornithine decarboxylase (ODC) induction. After a 2‐week feeding period UV‐induced ODC activity in mice receiving 12 or 20% menhaden oil was 3 to 13‐fold lower than that of corn oil fed animals. Further studies showed that edema was also markedly decreased. Animals receiving menhaden oil required twice the level of irradiance to evoke a comparable erythema as that which occurred in corn oil fed animals.Menhaden oil exerted significant influence upon carcinogenic expression, as manifested in significantly longer tumor latent periods and lower tumor multiplicities when compared to corn oil fed animals. Although the mechanism(s) of these menhaden oil effects remains unknown, it is clear that this unique lipid has a pronounced influence upon cutaneous photoresponses. 15th Annual Meeting of the American Society for Photobiology, Bal Harbor, FL, June, 1987.