bluuebunny/crossref_metadata_2025 huggingface dataset:
PHOTODYNAMIC THERAPY‐INDUCED HYPOXIA IN RAT TUMORS and NORMAL TISSUES
Authors: Hirsch B. D. , Walz N. C. , Meeker B. E. , Arnfield M. R. , Tulip J. , McPhee M. S. , Chapman J. D.
Published: January 2008

AbstractThe administration of misonidazole (MISO) to Fischer x Copenhagen rats whose R3327‐H prostate tumors were treated with photodynamic therapy (PDT) produced enhanced tumor growth delays and cures. This potentiation of PDT by MISO was previously observed with R3327‐AT tumors and was postulated to result from drug cytotoxicity of naturally‐occurring and PDT‐induced hypoxic cells. Radioactively‐labelled MISO has been developed as a marker for tissue p02at the cellular level and [3H]MISO was administered to R3327‐AT and R3327‐H tumor‐bearing rats before and after standard PDT treatments. The amount of3H in tissues 24 h after drug administration was a measure of‘bound MISO’which reflects average tissue oxygenation. [3H]MISO retained in R3327‐AT tumors was ˜4x and in liver tissue ˜2x that retained in muscle, heart, brain and R3327‐H tumors (1x). Tumors treated with Photofrin II and lased with 1000 J showed a 6‐fold increase in retained [3H]MISO in R3327‐H tumors and a 2‐fold increase in retained [3H]MISO in R3327‐AT tumors. The absolute levels of retained3H in both tumors after PDT were similar. These data provide direct evidence that PDT induces rapid hypoxia in both tumors. When the gastrocnemius muscle of the rat leg was similarly treated, the amount of [3H]MISO retained was ˜4x greater than that in untreated muscle. This result suggests that PDT‐induced hypoxia is not selective to just tumor tissue. These data suggest that the hypoxia‐inducing property of PDT might be exploited in combination with hypoxic cell cytotoxins to produce improved tumor responses and cures.
RATIOING FLUOROMETER PROBE FOR LOCALIZING CARCINOMA IN SITU IN BRONCHI OF THE LUNG
Authors: Balchum Oscar J. , Profio A. Edward , Razum Nicholas
Published: January 2008

Abstract A bronchoscopic ratioing fiuorometer probe, that ratios the red light emitted from bronchial tumor to the green light of autofluorescence upon stimulation by violet light (413 nm) has proven capable of detecting and localizing small bronchial tumors bronchoscopically, 4, 48, and 72 h after intravenous Photofrin II injection. Still to be determined is whether‘field averaging’in the case of very small bronchial carcinoma in situ will diminish accuracy. The accuracy, efficiency, and cost of localization by imaging fluorescence bronchoscopy will be compared to that by non‐imaging ratioing fiuorometer probe.
CLINICAL LASER PHOTODYNAMIC THERAPY IN THE TREATMENT OF BLADDER CARCINOMA
Authors: Shumaker B. P. , Hetzel F. W.
Published: January 2008

Abstract The treatment of bladder carcinoma using dihematoporphyrin ether (DHE) and laser photodynamic therapy (PDT) is described herein. Patients selected for this study have cytology‐ and biopsy‐proven transitional cell carcinoma, no histologic evidence of muscle invasion, and negative excretory urograms.

Sixteen patients have been treated, with follow‐up from 6 to 36 months. Eleven have had a complete response, and 3 a partial response in that they required re‐treatment for recurrence. Two of these patients have not recurred at this time. One of the patients who recurred had tumor extension into the prostatic urethra and has been successfully re‐treated (disease‐free at 6 months). There was one treatment failure and 1 patient lost to follow‐up.

Photosensitivity for up to 4 weeks is a known side‐effect, but unexpected morbidity included a transient but significant increase in urinary frequency, urgency, and occasionally hematuria which spontaneously resolved within 3‐4 weeks. Careful placement of the fiberoptic tip in the centre of the bladder, bladder distension during treatment with saline rather than water, the instillation of the minimum volume required to “smooth out” the mucosa for complete bladder photoradiation, and delivered energy of 25 J cm’or less may have prevented the more severe complications (i.e. bladder shrinkage) reported by Dougherty and Nseyo (personal communication).

We also feel that there is some early evidence that a heightened immune response (similar to intravesical BCG) may potentially play some role in explaining the efficacy of PDT in long disease‐free intervals, although this is just a histologic observation at present.

It appears the PDT offers another practical treatment modality for non‐invasive transitional cell carcinoma in patients refractory to standard surgical and chemotherapeutic regimens, and has been addressed by numerous other investigators such as Benson (1985) and Hisazumi (1983). We are presently recommending to our patients in these categories to undergo a course of PDT prior to relinquishing to cystectomy.
FLAGELLUM AUTOFLUORESCENCE and PHOTOACCUMULATION IN HETEROKONT ALGAE
Authors: Müller D. G. , Maier I. , Müller H.
Published: January 2008

Zoids of various brown algae capable of positive or negative phototaxis show strong autofluorescence of their posterior fiagellum and flagellar swelling when excited with blue light of 450 nm. This effect is lacking in zoids without stigma and phototactic capability. Fluorescence studies on living cells point to a flavin as photoreceptor pigment. The spectral sensitivity curve of photoaccumul‐ation suggests a carotenoid pigment (maximum 430–450 nm) being involved, with no effect below 380 nm and above 540 nm. The results obtained in this study indicate a flavin as photoreceptor pigment, which is periodically shaded by a carotenoid stigma.
PHOTO‐OXIDATION EFFECTS ON β‐HYDROXYBUTYRATE DEHYDROGENASE: STUDIES OF MEMBRANE FRAGMENTS AND INTACT MITOCHONDRIA
Authors: Robinson R. S. , Roberts A. J. , Campbell I. D.
Published: January 2008

The influence of singlet oxygen (1O2), generated by red light irradiation of oxygenated suspensions containing aluminium phthalocyanine sulphonate, on the membrane bound enzyme β‐hydroxybutyrate dehydrogenase was investigated. The inactivation rates were measured using a spectrophotometry assay which involves disruption of the mitochondria. A novel NMR assay was also used to measure the activity of the enzyme in intact mitochondria. Relatively high inactivation rates of around 109M−1 s−1 were observed in H2O buffer, and rates in D2O were a factor of 1.7 faster. Significant differences in enzyme inactivation rates by 1O2 were observed, not only between disrupted and intact mitochondria but also between the NMR assay results and the spectrophotometric assay results. The results indicate the value of a specific assay which does not require the disruption of the biological system.
EXCISION REPAIR OF PYRIMIDINE DIMERS IN MARSUPIAL CELLS
Authors: Applegate L. A. , Ley R. D.
Published: January 2008

Monodelphis domestica was further characterized as a model for photobiological studies by measuring the excision repair capabilities of this mammal's cells both in vivo and in vitro. Excision repair capability of the established marsupial cell line, Pt K2 (Potorous tridactylus), was also determined. In animals held in the dark, we observed that ˜50% of the dimers were removed by 12 and 15 h after irradiation with 400 J m−2 and 600 J m−2, respectively, from an FS‐40 sunlamp (280–400 nm). Cells from primary cultures of M. domestica excised˜50% of the dimers by 24 h after irradiating with 50 J m−2 and 36 h after exposure to 100 J m−2 with no loss of dimers observed 24 h following a fluence of 300 J m−2. Pt K2 cells were observed to have removed ‐50% of the dimers at ‐12 h after 50 J m−2 with only ‐10% of the dimers removed at 24 h following 300 J m−2. The observed loss of pyrimidine dimers from epidermal DNA of UV‐irradiated animals and from fibroblasts in culture, held in the dark, suggests that these marsupial cells are capable of DNA excision repair.
DRUG AND LIGHT DOSE DEPENDENCE OF PHOTODYNAMIC THERAPY: A STUDY OF TUMOR CELL CLONOGENICITY AND HISTOLOGIC CHANGES
Authors: Fingar Victor H. , Potter William R. , Henderson Barbara W.
Published: January 2008

Abstract— The dependence of photodynamic therapy (PDT) on changes in drug and light doses was determined in C3H/HeJ mice bearing the RIF tumor. Measurements of tumor clonogenicity were determined 24 h after PDT over a range of drug and light doses. Representative histological samples were prepared at each of these doses. Both the drug and light dose dependence experiments showed an exponential decrease in clonogenicity after an initial shoulder region. Reciprocity of drug and light dose was established from those clonogenicity curves. Histological examination of tumors gave information concerning the localization of gross damage within tumors. Increases of light dose in PDT were shown to extend the depth of necrosis within tumors. Increases of drug dose produced enlargements in the area of necrotic spots produced by PDT
TIME‐DEPENDENT EFFECTIVENESS OF FAR‐RED LIGHT ON THE PHOTOPERIODIC INDUCTION OF BULB FORMATION IN Allium cepa L.
Authors: Lercari Bartolomeo , Deitzer GeraldF.
Published: January 2008

Abstract. The photoperiodic induction of bulbing in onion (Allium cepa L.) by long daylengths has an absolute requirement for far‐red energy during the light period. Far‐red light promotes bulbing most effectively during the middle portion of an 18‐h inductive photoperiod, requiring about 5 times as much energy for the same response at the beginning and end of this photoperiod. The most effective wavelength for this promotion is 714 nm, suggesting that it is mediated through the high irradiance response (HIR) of phytochrome.
WAVELENGTH‐DEPENDENCE OF THE PHOTOREACTIVABLE RESPONSE OF DARK‐REPAIR‐DEFICIENT phr MUTANTS OF Escherichia coli K‐12
Authors: Smith A. W. , Moss S. H.
Published: January 2008

Abstract. The efficiency of photoreactivation with respect to the wavelength of photoreactivating light in similarly dark‐repair‐deficient but non‐isogenic phr+, phrA and phrB mutants of E. coli shows a structureless peak over the range 360 to 400 nm. These data suggest that the light‐dependent repair observed in the phrB mutant is similar to enzymatic photoreactivation and may be mediated by an unknown photoactive protein.
PHOTO‐INDUCED OXIDATIVE ACTIVATION OF THE ANTITUMOR DRUG 2N‐METHYL‐9‐HYDROXYELLIPTICINIUM IN VITRO
Authors: Auclair Christian
Published: January 2008

Abstract— The phenolic antitumor drug 2N‐methyl‐9‐hydroxyellipticine (NMHE) has been found to undergo oxidative activation upon irradiation with near‐UV light at 365 nm (UVA) in aqueous medium. In the presence of leucine used as biological nucleophile, UVA‐induced activation of NMHE results in covalent binding as shown by the generation of the corresponding adduct isobutyl‐oxazolopyridocarbazole (IB‐OPC). The reaction involves as the initial step the one‐electron transfer from the drug to molecular oxygen yielding superoxide anion (O2‐) whereas the generation of IB‐OPC may proceed either through a free radical reaction or a Michael addition reaction. The UVA light‐induced production of IB‐OPC is markedly increased by superoxide dismutase (SOD) and by the singlet oxygen quencher diazabicyclooctane (DABCO) but not affected by β‐carotene. It is concluded that UVA induces the oxidation of NMHE through an oxidasic process which may result in the covalent binding of the drug to biological nucleophiles. This finding leads to further investigation of the photodynamic action of NMHE in tumor cells.
PHOTOREACTIONS OF TRIS(2,2′‐BIPYRIDYL)‐RUTHENIUM(II) WITH PEROXYDISULFATE IN DEOXYGENATED AQUEOUS SOLUTION IN THE PRESENCE OF NUCLEIC ACID COMPONENTS, POLYNUCLEOTIDES, AND DNA*
Authors: Görner Helmut , Stradowski Czeslaw , Schulte‐Frohlinde Dietrich
Published: January 2008

Abstract— The photobleaching of excited tris(2,2′‐bipyridyl)‐ruthenium(II), *Ru(bpy)32+, by peroxydis‐ulfate in the presence of DNA and a series of polynucleotides, mononucleosides (uridine, cytidine, adenosine, guanosine), and purine or pyrimidine bases was studied in deoxygenated aqueous solution at room temperature. A reaction scheme is proposed which is confirmed by data obtained from mixing experiments with Ru(III) and bleaching measurements of Ru(II) using either continuous visible light or a nanosecond laser pulse (353 nm). The primary photobleaching step is the formation of Ru(bpy)32+ and the SO4‐ radical anion. In the presence of nucleic acids the two oxidizing species are formed in close proximity to the strand, since we used conditions where the Ru(bpy) 32+ ion is bound to the strand. Concerning the secondary reactions two clear cases (and several more complex cases) can be distinguished. On addition of uracil to the Ru(bpy)32+/S2O82‐ system the quantum yield for photobleaching is not significantly changed (φrel⋍ 0.95), whereas it drops to virtually zero for guanosine‐containing substrates, including DNA. The former result is explained by a reaction of SO4‐ with uracil leading to theN–1 radical which oxidizes Ru(II) to Ru(IIl). In contrast, the guanine moiety reacts with Ru(III) converting it into Ru(II). Therefore, in the presence of S2O82‐ and a substrate carrying a guanine moiety, Ru(bpy32+ acts as a photocatalyst.
EXCISION REPAIR OF UVR‐INDUCED PYRIMIDINE DIMERS IN CORNEAL DNA
Authors: Freeman Steven E. , Applegate Lee A. , Ley Ronald D.
Published: January 2008

Abstract— We measured excision repair of ultraviolet radiation (UVR)‐induced pyrimidine dimers in DNA of the corneal epithelium of the marsupial, Monodelphis domestica, using damage‐specific nucleases from Micrococcus luteus in conjunction with agarose gel electrophoresis. We observed that 100 J ‐2 of UVR from aFS–40 sunlamp(280–400 nm) induced an average of 2.2 ± 0.2 times 10‐2 endonuclease‐sensitive sites per kilobase (ESS/kb) (pyrimidine dimers) and that ∼ 50% of the dimers were repaired within 12 h after exposure. We also determined that an exposure of 400 J m‐2 was needed to induce comparable numbers of pyrimidine dimers (2.5 times 10‐2) in the DNA of skin of M. domestica in vivo. In addition, we found that 50% of the dimers were also removed from the epidermal cells of M. domestica within 12 h after exposure. A dose of 100 J m‐2 was necessary to induce similar levels of pyrimidine dimers (2.0 ± 0.2 times 10‐2) in the DNA of the cultured marsupial cell line Pt K2 (Potorous tridactylus).
ACRYLAMIDE AND MOLECULAR OXYGEN FLUORESCENCE QUENCHING AS A PROBE OF SOLVENT‐ACCESSIBILITY OF AROMATIC FLUOROPHORES COMPLEXED WITH DNA IN RELATION TO THEIR CONFORMATIONS: CORONENE‐DNA AND OTHER COMPLEXES
Authors: Zinger David , GEACiNTov Nicholas E.
Published: January 2008

Abstract— The relationships between the accessibilities to fluorescence quenchers (O2 and acrylamide) of three different aromatic molecules and their modes of binding to double‐stranded DNA were investigated. Proflavin was selected for this study because it is a known intercalator, while Hoechst 33258 is known to bind externally in the minor groove of DNA; it is shown here that the relatively bulky polycyclic aromatic hydrocarbon coronene forms partial intercalation complexes, and thus represents a third class of fluorophore‐DNA binding. Fluorescence quenching results suggest that Hoechst 33258 bound to DNA is fully accessible to 02, that the accessibility of partially intercalated coronene is reduced to 20% of the free‐solution value, while the accessibility of intercalated proflavin to molecular oxygen is at least ten times smaller than for free polycyclic aromatic molecules in fluid solutions. In contrast, the fluorescence of all these three fluorophores bound to DNA is insensitive to acrylamide (the effective accessibilities appear to be reduced by factors greater than 50 upon binding to DNA). It is concluded that O, is useful as a qualitative probe of the type of binding and solvent exposure of fluorophore‐DNA complexes, while acrylamide appears to be of limited utility. However, acrylamide fluorescence quenching may be useful for studies of other types of fluorophore‐DNA complexes since the fluorescence of the pyrene residues in covalent adducts derived from the binding of benzo(a)pyrene diol expoxide to DNA was found to be at least partially sensitive to acrylamide.
BIOLOGICAL ACTIVITIES OF PHTHALOCYANINES—VIII. CELLULAR DISTRIBUTION INV–79 CHINESE HAMSTER CELLS AND PHOTOTOXICITY OF SELECTIVELY SULFONATED ALUMINUM PHTHALOCYANINES
Authors: PAQUETTE BENOIT , ALI HASRAT , LANGLOIS RÉJEAN , VAN LIER Johan E.
Published: January 2008

Abstract— Water soluble chloro aluminum phthalocyanines sulfonated to different degrees are studied for phototoxicity and cellular distribution inV–79 Chinese hamster cells. The more hydrophobic disulfonated dyes, with sulfonate substituents on adjacent benzyl groups of the phthalocyanine ring structure, exhibited the best cell penetrating properties and the highest phototoxicity. Fluorescence microscopy revealed that the dye was uniformly distributed in the cytoplasm but absent in the nucleus. The greater cell membrane penetrating properties of the lower as compared to the higher sulfonated dyes are attributed to the amphiphilic nature of the former.
PRODUCTION OF PHOTOREACTIVEABLE LESION IN THE YEAST S. cerevisiae BY IRRADIATION WITH 193 nm EXCIMER LASER LIGHT
Authors: Winckler K. , Golz B. , Laskowski W. , Bende T.
Published: January 2008

Abstract— Far‐UV (193nm) excimer‐laser irradiation of an excision‐repair defective but photoreactivatiozn competent strain of Saccharomyces cerevisiae (XS774–6A) produces a significant amount of photoreactiveable DNA‐lesions. The irradiation was applied by a laser planned for micro‐surgery in ophthalmology using doses and dose rates even lower as needed during the surgical use. Irradiation experiments on solid agar plates show a sharp bordered area of growth‐inhibition around the impact of the laser‐beam up to a diameter of 2 cm even for a radiation‐repair competent wildtype strain. In this area photoreactivation of cells is detectable, proving the induction of pyrimidine‐dimers in cells surrounding the laser‐beam impact zone.
PHOTOMODIFICATION OF HUMAN ERYTHROCYTES: EXTERNAL HEAVY ATOM EFFECT, SELECTIVE PERMEABILITY AND PROPERTIES OF THE ANION PERMEATION PATHWAY
Authors: Pooler John P.
Published: January 2008

Abstract— Anion permeability was studied in normal and photomodified erythrocytes and the role of anion species in photomodification and singlet oxygen generation was evaluated. Relative permeability to halides and nitrate was assessed using lysis rates in valinomycin‐treated cells to make anion permeation rate‐limiting. In non‐photomodified cells the normal high temperature dependence (E:, = 67 kJ/mol; 16 kcalhol), selectivity sequence (NO, > I > Br > F > Cl) and sensitivity to block by the stilbene derivative HzDIDS were confirmed. In cells photomodified by illumination in the presence of phloxine B the anion permeability was severely perturbed. The temperature dependence was strongly reduced, the permeability to ions other than fluoride increased, leading to a reversal of the F/CI selectivity, and the capacity to be blocked by HIDIDS was lost. Pretreatment with NEM and posttreatment with DTE did not affect rates of photohemolysis. The amount of photomodification varied with species of anion present in the reaction medium, being greatest for F and smallest for I. Rates of singlet oxygen generation in aqueous solution measured by the RNO bleaching method followed the same anion sequence, suggesting a strong external heavy atom effect.
LONGWAVE ULTRAVIOLET RADIATION (UVA)‐INDUCED ALTERATION OF EPIDERMAL DNA SYNTHESIS
Authors: Chew Stephanie , Deleo Vincent A. , Harber Leonard C.
Published: January 2008

Abstract— Longwave ultraviolet radiation(UVA–320–400nm) is known to induce inflammation, pigmentation and tumor production in mammalian skin. The mechanisms by which such radiation induces these biologic phenomena are poorly defined. In an effort to broaden our knowledge in this area, we examined the effect of UVA on DNA biosynthesis in Hartley strain albino guinea pig skin. The animals were irradiated with selected doses of solar simulated UVA, and DNA was assayed by [3H]thymidine incorporation into epidermal DNA by autoradiography. These studies revealed that UVA inhibited DNA synthesis in a dose dependent manner between 40 and 80 J cm‐2 at 3 h post‐irradiation. This inhibition was followed by a stimulation of synthesis at 5 h and a second inhibition/ stimulation at 8 and 24 h, respectively. Although the mechanism of alteration is undefined, our data suggest that UVA has profound effects on DNA biosynthesis in mammalian epidermis.
THE EFFECT OF PHOTODYNAMIC THERAPY ALONE AND IN COMBINATION WITH MISONIDAZOLE OR X‐RAYS FOR MANAGEMENT OF A RETINOBLASTOMA‐LIKE TUMOUR †
Authors: Wlnther J. , Overgaard J. , Ehlers N.
Published: January 2008

Abstract— The effect of photodynamic therapy alone and combined with misonidazole or X‐rays has been investigated in an intraocular retinoblastoma‐like tumor. Tumour control rate was achieved up to 33% and depended both on the light energy doses and the Photofrin II doses. Misonidazole injected prior to light irradiation did not enhance the photodynamic therapy response, although the misonidazole was uptaken by the tumor tissue. The combination of X‐rays and photodynamic therapy demonstrated both in vivo and in vitro not more than a simple additive effect and there was no difference between X‐rays given before or after the light irradiation.
PROTECTION OF Ustilago violacea FROM TOLUIDINE BLUE PHOTOSENSITIZATION and HYDROGEN PEROXIDE INDUCED KILLING and MITOTIC RECOMBINATION BY CAROTENES
Authors: Will III OscarH , Sawtelle David E. , Iverson Pamela , Jorve Kara
Published: January 2008

Abstract— The accumulation of (J‐carotene in the ph/ph + y diploid strain of the smut fungus Ustilago violacea was associated with reduced killing and lower levels of induced mitotic recombination compared to the β‐carotene lacking ph/ph+ w strain in response to both incandescent photosensitization and treatment with H202. The ph/ph+ y strain was only slightly more resistant to killing by exogenous toluidine blue (TB) photosensitization. The ph/ph+ y strain exhibited significantly greater levels of survival when exposed to incandescent radiation and 1.5 μ.M TB for 15 min, as well as 3.0. 0.3, 0.03, 0.003% H202 in the dark. The ph/ph+ y strain also exhibited lower levels of mitotic recombination after endogenous TB photosensitization and the latter two H202 treatments. Similar survival results were obtained for the carotene accumulating haploid strain l.C2y and the carotene lacking haploid strain l.C2iv in response to H202 exposure.
INTERMEDIATES IN THE PHOTOCONVERSION OF FUNCTIONAL PHYTOCHROME IN FERN SPORES OF Dryopteris–II. In vivo KINETICS OF THE DECAY OF Ii700 AND OF THE FORMATION OF Pfr STUDIED WITH A DOUBLE‐LASER APPARATUS*
Authors: Scheuerlein R. , Inoue Y. , Furuya M.
Published: January 2008

Abstract— Photoconversion of the red‐light‐absorbing form of phytochrome, Pr, to the far‐red‐light‐absorbing form, Pfr, was investigated in vivo at 22°C with 600 or 800 ns laser pulses of high spectral purity and induction of spore germination in Dryopteris paleacea was used as indicator for the progress of photoconversion. This reaction is initiated by a saturating R‐laser pulse of 648.5 nm, establishing an equilibrium of the photochromic system between Pr and the very early intermediates, Ii700 (Prφ Ii700)‐ The decay of Ii700 as well as the formation of Pfr was recorded by the application of a second pulse varied between 698 and 717.5 nm, which inhibits the formation of Plr being absorbed predominantly by Ii700or Pfr, respectively.

The most effective inhibition for the second pulse is found up to 10 u.s after the first pulse and this is interpreted by photoreversion of Ii700 to Pr; thus reducing the formation of Pfr from Ii700. This early inhibition decreases between 10 μs to 100 ms after the R‐laser pulse, as a result of the decay of Iibl to a bleached species I,;. This decay can be described by three first order kinetics with the rate constants k12= 16830 ± 2970 s‐1, k12= 666 ± 218 s‐1,k13= 9.8 ± 0.9 s‐1. A second inhibition, due to the formation of Pfr, is found for dark intervals <100 ms and can be described by two first order kinetics with the rate constants k21= 2.9 ± 0.6 s‐1 and k22= 0.17 s‐l.
3,4 AND 4′,5′‐PHOTOCYCLOADDUCTS BETWEEN 4′‐METHYLANGELICIN AND THYMINE FROM DNA
Authors: Caffieri S. , Luccmni V. , Rodighiero P. , Miolo G. , Dall'Acqua F.
Published: January 2008

Abstract— Two C4‐cycloadducts between 4′‐methylangelicin and thymine were isolated from the photo‐reaction (365 nm) between this furocoumarin and DNA. Their capacity to undergo photoreversion at 254 nm and their spectroscopic and NMR data allowed us to assign furan‐ and pyrone‐side structures, respectively, to these photocompounds. The former adduct has a cis‐syn configuration; the latter. which was also isolated from a photoreaction between the furocoumarin and thymine in water‐methanol solution, was assigned a cis‐anti structure.
PHOTODYNAMIC SENSITIZERS FROM CHLOROPHYLL:PURPURIN–18 AND CHLORINp6
Authors: Hoober J. Kenneth , Sery Theodore W. , Yamamoto Nobuto
Published: January 2008

Abstract— Two easily prepared derivatives of chlorophyll,purpurin–18 and chlorin p6, are potent sensitizers of cell killing by low‐intensity red light. The internal anhydride group inpurpurin–18 provides the potential of covalently linking in one step the chlorin to cell targeting agents such as antibodies.
SPECTRAL ANALYSIS OF CHLOROPHYLL a AGGREGATES IN THE PRESENCE OF WATER‐SOLUBLE MACROMOLECULES
Authors: Uehara Kaku , Mimuro Mamoru , Fujita Yoshihiko , Tanaka Makoto
Published: January 2008

Abstract— The absorption and fluorescence spectra of chlorophyll a (Chi a) aggregates formed in aqueous solutions of polyvinyl alcohol) (PVA), polyvinyl pyrrolidone) (PVP), and bovine serum albumin (BSA) were analyzed by curve‐fitting methods in the wavelength region from 650 to 800 nm. The results indicated that the aggregation of Chi a to polymeric forms such as (Chia–2H20), was suppressed in the presence of the macromolecules. The suppression was due to a coordination of macromolecule bound ligands to Chi a and was strongest in BSA and weaker in PVA. There were differences in the spectra even though the same types of polymeric Chi a forms were observed due to characteristically different composition of these forms. Fluorescence patterns indicated that energy was transferred from the shorter to the longer wavelength forms.
PSORALEN AND THE SUPPRESSION OF MELATONIN SECRETION BY BRIGHT LIGHT
Authors: Souetre E. , Salvati E. , Lacour J. C. , Belugou J. L. , Krebs B. , Ortonne J. P. , Darcourt G.
Published: January 2008

Abstract— Melatonin plasma levels were analyzed in 21 normal human subjects placed in darkness frm 7:30 p.m. to 11 p.m. and then submitted to bright light exposure (over 1500 lx) to 2 a.m. 5‐Methoxypsoralen (5‐MOP) was orally (40 mg) given to 11 of those subjects at 9 p.m. In darkness, melatonin plasma levels increased slightly in untreated subjects and dramatically in subjects having received 5‐MOP. Under bright light exposure, the melatonin plasma levels were significantly reduced in drug free controls but not in treated subjects.
SANGUINARINE, A PHOTOTOXIC H2O2‐PRODUCING ALKALOID
Authors: Tuveson R. W. , Larson Richard A. , Marley Karen A. , Wang Gui‐rong , Berenbaum May R.
Published: January 2008

Abstract— Sanguinarine chloride, a quaternary salt of a benzophenanthrene alkaloid, was phototoxic to catalase‐deficient strains of Escherichia coli but not to Trichoplusia ni (cabbage looper moth larvae), an insect with high levels of catalase activity. Chemical analyses confirm that sanguinarine is an efficient producer of H2O2. This differential toxicity suggests that the mode of phototoxic action involves production of H2O2 which could be detoxified in many organisms by catalase.
ATP‐GTP‐BINDING PROTEINS AND ENDOGENOUS ADP‐RIBOSYL TRANSFERASE IN Lemna paucicostata 441
Authors: Hasunuma Kohji , Takimoto Atsushi
Published: January 2008

Abstract— A crude extract containing membrane components of Lemna paucicostata was treated with 1% Lubrol PX and fractionated by gel nitration. Binding activities to non‐hydrolyzable analogues of ATP, [35S]ATPγS (adenosine 5′[;γ‐thio]triphosphate) and that of GTP, [35S]GTPγS (guanosine 5′[γ‐thiojtriphosphate) were detected in some fractions, and these activities were prevented in the presence of 0.1 mM ATP or GTP. ATP and GTP were 2 to 3 orders of magnitude more effective than CTP or UTP in preventing this binding activity. These fractions showed ATPase and GTPase activities with 1 nM [γ‐32P]ATP or [γ–32P]GTP substrate. Analyses by sodium dodecyl sulfate polyacrylamide gel electrophoresis of these fractions after binding with [35S]ATPγS or [35S]GTP‐γ S revealed that these fractions contained [35S]ATPγS and [35S]GTPγS binding proteins with molecular weights of 53 000 and 60 000, respectively. Both of these proteins were [32P]ADP‐ribosylated by endogenous ADP‐ribosyl transferase. Three proteins with molecular weights of 11 000, 12 000 and 13 000 which could bind [35S]ATP7S or [‐35S]GTP‐γ S were ADP‐ribosylated by endogenous ADP‐ribosyl transferase. Pertussis toxin stimulated ADP‐ribosylation of these proteins. Four proteins with molecular weight of 37 000, 50 000, 80 000 and 115 000 with PSS]ATP7S and [,3S]GTP7S binding activities were also detected. The signal transduction of light to underlying clock mechanism in Lemna may be controlled by ATP‐GTP‐binding proteins and by the ADP‐ribosylation of these proteins.
PHOTOOXIDATIVE DESTRUCTION OF CHLOROPLASTS AND ITS EFFECT ON NUCLEAR GENE EXPRESSION AND EXTRAPLASTIDIC ENZYME LEVELS *
Authors: OELMÜLLER RALF
Published: January 2008

Abstract The cooperation between the nuclear and plastidic genome has been investigated extensively and it is generally accepted that plastidic development is controlled by the genetic information encoded in the nucleus (Ellis, 1981). It was discovered only recently that plastids are also involved in controlling extraplastidic events. If carotenoid‐free plastids are destroyed by photooxidation. expression of plastidic proteins which are encoded in the nucleus is reduced or prevented. Thus is has been postulated that a signal which derives from the plastids controls the expression of these genes in the nucleus. Moreover, extraplastidic enzymes with functions related to intact plastids (such as nitrate reductase and peroxisomal enzymes) are also affected by this treatment, while (photo)morphogenesis and extraplastidic compounds not directly related to plastidic functions seem to be unaffected. Since the damage is restricted exclusively to the plastids and even the outer envelope membrane appears to be unimpaired, photooxidative destruction of carotenoid‐free plastids is often used as a tool to investigate nuclear plastid interaction. This review briefly describes the events occurring during photodamage, analyzes the consequences for extraplastidic events, and discusses the implication of a plastidic signal(s) in controlling the expression of nuclear genes which code for plastidic proteins.
SPINACH FERREDOXIN REDUCTION BY MEMBRANE‐BOUND CHLOROPHYLL TRIPLET STATE VIA A DIQUAT MEDIATOR
Authors: SENTHILATHIPAN VELU , TOLLIN GORDON
Published: January 2008

Abstract Laser flash photolysis experiments have shown that the diquat analog containing a propylene bridge (PDQ2+), when electrostatically bound to negatively‐charged vesicles containing chlorophyll, is able to mediate the rapid reduction (k= 1.1 × 105 s‐1) of spinach ferredoxin via electron transfer quenching of triplet state chlorophyll. The kinetics of formation and decay of reduced ferredoxin are consistent with a mechanism involving complex formation between oxidized ferredoxin and vesicle‐bound PDQ2+. Under optimal conditions, approximately 15% of the quenched triplets yield reduced ferredoxin. This process is a model for soluble ferredoxin reduction which occurs in green plant photosystem I, and results in an appreciable storage of electromagnetic energy in the reaction products.
OXYGEN CONSUMPTION AND LUMINESCENCE OF ISOLATED Porichthys PHOTOPHORES IN RESPONSE TO ADRENERGIC STIMULATIONS
Authors: Mallefet J. , Baguet F.
Published: January 2008

Abstract—

Isolated photophores of Porichthys maintained in saline at 20oC, consume oxygen at a mean rate of 115 ± 5 ± 10 3 nmol O2 min1 (n= 165).

In the presence of 0.1 and 1 mM adrenalin or noradrenaline the photophore produces a fast peak of light followed by a slow luminescence. A large increase in oxygen consumption occurs prior to the fast light response and it remains slightly above the resting level during the following slow light emission.

When isolated photophores do not produce the fast peak of light(in response to isoprenalin or after treatment with phentolamine), there is only a slight transient increase of oxygen consumption. During the production of the slow luminescence the oxygen consumption remains close to the resting level.

A relationship between the oxygen consumption and the light emission during the fast luminescence has been found: it is suggested that most of the oxygen consumed could be involved in a triggering mechanism of light production.
MOLECULAR MECHANISM OF DRUG PHOTOSENSITIZATION–II. PHOTOHEMOLYSIS SENSITIZED BY KETOPROFEN
Authors: Costanzo L.L. , Guidi G.De , Condorelli G. , Cambria A. , Fama M.
Published: January 2008

Abstract—

Red blood cell lysis photosensitized by ketoprofen (KPF) was investigated. The photohem‐olysis was inhibited by butylated hydroxyanisole, reduced glutathione, superoxide dismutase and mannitol, and was unaffected by sodium azide; the presence of oxygen markedly enhanced the lysis. Photohemolysis was also observed under anaerobic conditions. Ketoprofen, irradiated in aqueous buffer solution at pH 7.4, underwent a decarboxylation process via intermediate radicals, leading to the compounds (3‐benzoylphenyl)ethane, (3‐benzoylphenyl)ethyl hydroperoxide, (3‐benzoylphenyl)‐ethanol and (3‐benzoylphenyl)ethanone under aerobic conditions and only to the compound (3‐benzpylphenyl)ethane under anaerobic conditions.

The four photoproducts showed lytic activity, particularly high for the alcohol and hydroperoxide.

The overall results suggest for KPF‐photosensitized hemolysis a molecular mechanism involving free radicals, superoxide anion and sensitizer photodegradation products.
DNA LESIONS AND DNA DEGRADATION IN MOUSE LYMPHOMA L5178Y CELLS AFTER PHOTODYNAMIC TREATMENT SENSITIZED BY CHLOROALUMINUM PHTHALOCYANINE
Authors: Ramakrishnan Narayani , Oleinick Nancy L. , Clay Marian E. , Horng Min‐Fen , Antunez Antonio R. , Evans Helen H.
Published: January 2008

Abstract—

Two closely related strains of mouse lymphoma L5178Y cells, LY‐R and LY‐S, have been found to differ in their sensitivity to the cytotoxic effects of photodynamic treatment (PDT) with chloroaluminum phthalocyanine (CAPC) and red light. Strain LY‐R is more sensitive to photodynamic cell killing than strain LY‐S. Differences in uptake of CAPC could not account for the differences in cytotoxic effects. There was no marked difference between the two strains in the induction of single‐strand breaks (which includes frank single‐strand breaks and alkali‐labile lesions), but substantially more DNA‐protein cross‐links were formed in strain LY‐R by CAPC and light. Repair of single‐strand breaks proceeded with similar kinetics in both strains for the first 30 min post‐irradiation, suggesting that these lesions are not responsible for the differential sensitivity of the two strains to the lethal effects of photodynamic treatment. Thereafter, alkaline elution revealed the presence of increasing DNA strand breakage in strain LY‐R. DNA degradation, as measured by the conversion of prelabled [14C] DNA to acid‐soluble radioactivity, was more rapid and extensive in strain LY‐R.
In vitro PHOTOSENSITIZATION WITH A BENZOPORPHYRIN DERIVATIVE
Authors: KESSEL DAVID
Published: January 2008

Abstract

Biophysical and photobiological properties of two benzoporphyrin derivatives were examined. These dyes exhibit substantial absorbance in the red, and are potent photosensitizers in vitro. After brief (0.5 h) incubations, phototoxicity was more closely correlated with membrane than with mitochondrial photodamage. Affinity of these dyes toward plasma lipoproteins are consistent with a mode of localization via the LDL‐mediated mechanism utilized by the hematoporphyrin‐derived product, HPD.
PHOTOREACTIONS OF MACROCYCLIC DYES BOUND TO HUMAN SERUM ALBUMIN
Authors: Davila Jorge , Harriman Anthony
Published: January 2008

Abstract— The photophysical properties of tetrakis(4‐sulfonatophenyl)porphyrin (H, TSPP), its tin (IV) complex (SnTSPP), aluminium(III) trisulfonatophthalocyanine (A1PCS), and the corresponding zinc(II) complex (ZnPCS), have been measured in H2O, D2O, and upon binding to human serum albumin (HSA). The triplet excited states of the various macrocyclic dyes generate singlet molecular oxygen, O2(1Δg) in high quantum yield upon illumination in Cysaturated solution, even in the presence of HSA. The triplet states also abstract an electron from 4‐aminophenol, forming the radical anion of the macrocycle. Quenching rate constants and quantum yields have been measured for the various processes in the presence and absence of HSA. It is found that HSA binds all the dyes at nonspecific sites close to the interface in such a manner that the dyes remain accessible to species residing in the solution phase. Dyes that do not possess axial ligands complexed to the central cation (e.g. H2TSPP, ZnPCS) are able to bind also at a deeper, more specific site on the protein where they are protected from species in solution. Under such conditions, triplet quenching by 4‐aminophenol is restricted to long‐distance electron tunnelling, for which the rate is relatively slow.
PHOTOLYTIC COVALENT BINDING OF INDOLEACRYLIC ACID TO DNA*
Authors: Farrow Sherry J. , Mohammad Taj , Baird William , Morrison Harry
Published: January 2008

Abstract— E‐β‐IndoI‐3‐ylacrylic acid (IA), radiolabeled at the 2 position with l+C, and calf thymus DNA have been irradiated with UV light (Λ > 280 nm) in phosphate buffer (pH 7.0). Re‐isolation of the DNA indicates covalent binding of IA at levels of up to 295 nmol IA/mg native DNA (0.097 IA/ base). Binding is observed for both native and heat denatured DNA, but is more efficient with the latter. Quantum efficiencies of 2.60 times 10−5 and 2.30 times 10 −4 mol IA bound to native DNA/mol photon absorbed have been measured at 308 and 266 nm, respectively. Studies with the four polyribonucleotides indicate a strong preference for binding to poly[U]. Photolysis of either untreated or enzymatically degraded labeled native DNA with 254 nm light leads to the reformation of IA, and a 2 + 2 photocy‐cloadduct of IA and thymidine has been isolated and characterized and matched by HPLC to a DNA derived adduct. Equilibrium dialysis studies provide no evidence for preassociation of IA to DNA.
“ENERGY”‐DEPENDENT QUENCHING OF CHLOROPHYLL FLUORESCENCE and THERMAL ENERGY DISSIPATION IN INTACT LEAVES DURING INDUCTION OF PHOTOSYNTHESIS
Authors: Havaux Michel
Published: January 2008

Abstract— Intact leaves, previously adapted to darkness for a prolonged period of time, were suddenly illuminated with a strong, photosynthetically saturating, white light (ca 1500 μmol m−2 s_1), resulting in the rapid establishment of a large energy‐dependent chlorophyll fluorescence quenching (qE) as shown by in vivo fluorescence measurements with a pulse amplitude modulation technique. Two different photothermal methods, photoacoustic spectroscopy and photothermal deflection spectroscopy, were used to monitor thermal deactivation of excited pigments during the dark‐light transitions. The in vivo photothermal signals measured with both techniques were shown to remain constant during induction of photosynthesis under high light conditions, suggesting that, in contrast to current hypotheses, energy‐dependent quenching qE is not associated with significant changes in thermal dissipation of absorbed light energy in the chloroplasts. When photosynthesis was induced with a low‐intensity modulated light, a noticeable decrease in the heat emission yield was observed resulting from the progressive activation of the competing photochemical processes.
PICOSECOND DYNAMICS OF THE EXCITED STATE RELAXATIONS IN PHYTOCHROME
Authors: Hermann Gudrun , Lippitsch Max E. , Brunner Harald , Aussenegg Franz R. , Müller Eberhard
Published: January 2008

Abstract— A comparative study of the picosecond kinetics of rye (Secale cereale L.) phytochrome, its 39 and 23 kDa chromopeptides and deuterated rye phytochrome has been carried out. Evidence is presented that the fluorescence decay of Pr contains a very short lifetime component (14 ps) which has escaped detection in the fluorescence studies reported so far. Thus, the overall decay is well described by four exponential components, two rapid (14 and 44 ps) and two slower ones (157 and 690 ps). The fluorescence decays of deuterated Pr and of a 39 and 23 kDa chromopeptide of Pr also require the analysis in terms of four exponentials for a good fit. Some of the lifetime and amplitude values obtained differ significantly from the values estimated for Pr. In the chromopeptides, the two longer components have distinctly slower decays. For the two faster components the lifetimes remain approximately the same, but their relative amplitudes vary greatly. In deuterated Pr, the lifetimes are affected only slightly by deuteration. In contrast, the decay amplitudes are strikingly altered. Moreover, from a rate equation simulation modelling the observed fluorescence kinetics, it turns out that the yields for the various deactivation steps in the chromopeptides and in deuterated Pr reveal differences from the corresponding values in Pr. The implications of the results presented with respect to the influence of the protein moiety of Pr on the picosecond relaxation process are discussed.
RHYTHMIC REGULATION OF THE LIGHT‐HARVESTING CHLOROPHYLL alb PROTEIN and THE SMALL SUBUNIT OF RIBULOSE‐1,5‐BISPHOSPHATE CARBOXYLASE mRNA IN RYE SEEDLINGS
Authors: Ernst D. , Apfelbock A. , Bergmann A. , Weyrauch C.
Published: January 2008

Abstract— In etiolated rye seedlings transferred to light the expression of chlorophyll alb binding protein mRNA varies when the seedlings are grown in a day/night cycle. The fluctuation pattern follows a circadian rhythm. Exposure of 4‐day old etiolated seedlings to continuous white light revealed two maxima within the first 24 h before the 24 h cycle period appeared. These first two maxima are also observable after a pulse of white light or after a pulse of red light. These results indicate a possible involvement of phytochrome in the endogenous regulation of the rhythm.
PHYTOCHROME ACTION AT HIGH PHOTON FLUENCE RATES: RAPID EXTENSION RATE RESPONSES OF LIGHT‐GROWN MUSTARD TO VARIATIONS INFLUENCE RATE and RED: FAR‐RED RATIO*
Authors: Smith Harry
Published: January 2008

Abstract— Extension growth rate of light‐grown mustard (Sinapis alba L.) seedlings was monitored continuously using a sensitive linear displacement transducer system. When high fluence rates (ca 2 mmol m−2 s_1) of mixed red and far‐red light were presented to the growing internodes from fibre optic probes, fluctuations in extension rate occurred during the first 30 min. High red: far‐red ratios (R: FR) caused growth deceleration, whilst low R: FR caused transitory growth acceleration. These changes in extension rate were not exactly as predicted from the proportions of Pr (the red‐absorbing form of phytochrome) and Pfr (the far‐red absorbing form of phytochrome) calculated to be established by the light sources. Nevertheless, the data demonstrate that phytochrome is able to control extension growth at fiuence rates approaching those of summer sunlight, thereby providing the capacity to sense the presence of neighbouring vegetation before shading seriously compromises photosynthesis.

Varying fiuence rate over two orders of magnitude whilst maintaining R: FR constant evoked transient fluctuations in extension rate. At high R: FR, a 100‐fold step down in fiuence rate led, after a lag of ca 10 min, to a transient (i.e. 20 min) deceleration of extension that was followed by a marked transient (i.e. 20 min) acceleration. After a 100‐fold step up in fiuence rate, a transient (i.e. 20 min) acceleration only was observed, beginning after a lag of ca 10 min. When R: FR was low, neither a step‐down nor a step‐up in fluence rate resulted in appreciable fluctuations in extension rate.

The data are discussed in relation to the possible role played by the accumulation of photoconversion intermediates using a simple computer model for simulating active phytochrome concentrations at high fluence rates. The possibility that the mechanism for the photoperception of light quality by phytochrome may be capable of rapid adaptation to fluence rate fluctuations is proposed.
TIME‐GATED FLUORESCENCE OF BLEPHARISMIN, THE PHOTORECEPTOR PIGMENT FOR PHOTOMOVEMENT OF Blepharisma
Authors: Cubeddu Rlnaldo , Ghetti Francesco , Lenci Francesco , Ramponi Roberta , Taroni Paola
Published: January 2008

Abstract— A computer‐controlled apparatus for time‐resolved laser fluorescence spectroscopy has been used to measure fluorescence lifetimes, time‐integrated and time‐gated spectra of crude extracts of blepharismin, the photoreceptor pigment of the ciliated photoresponsive protozoan Blepharisma japonicum, in ethanol, aqueous solutions and detergent micelles. The effect of hydroxyl concentration has been investigated in both alcohol and water solutions. A short‐living (0.2‐0.4 ns) molecular species, emitting at 600 nm, is predominant in aqueous solutions at pH < 11.7, whereas in pure ethanol solutions an intermediate‐living species (about 1 ns), still fluorescing at 600 nm, prevails. Upon increasing OFF concentration, a third, long‐living (about4–6 ns) molecular species, emitting at 660 nm, is formed in all the examined media. This species has been tentatively identified as the negatively charged form of the photoreceptor pigment, whereas the short‐living and the intermediate‐living fluorescence emissions have been attributed respectively to the phenolic and the quinonic neutral forms of blepharismin. The phenolic form in its ground state is suggested to be the molecular species from which proton release occurs.