bluuebunny/crossref_metadata_2025_split huggingface dataset:
STRATEGIES FOR SELECTIVE CANCER PHOTOCHEMOTHERAPY: ANTIBODY‐TARGETED and SELECTIVE CARCINOMA CELL PHOTOLYSIS*
Authors: Oseroff A. R. , Ara G. , Ohuoha D. , Aprille J. , Bommer J. C. , Yarmush M. L. , Foley J. , Cincotta L. 
Published: January 2008

Abstract A principle objective in chemotherapy is the development of modalities capable of selectively destroying malignant cells while sparing normal tissues. One new approach to selective photochemo‐therapy, antibody‐targeted photolysis (ATPL) uses photosensitizers (PS) coupled to monoclonal antibodies (MAbs) which bind to eel) surface antigens on malignant cells. Selective destruction of human T leukemia cells (HBP‐ALL) was accomplished by coupling the efficient PS chlorin e6 to an anti‐T cell MAb using dextran carriers. Conjugates with chlorin : MAb ratios of 30 : 1 retained > 85% MAb binding activity, and had a quantum yield for singlet oxygen production of 0.7 ±0.1, the same as that of free chlorin e6. Cell killing was dependent on the doses of both MAb‐PS and 630‐670 nm light, and occurred only in target cell populations which bound the MAb. On the order of 1010 singlet oxygen molecules were necessary to kill a cell.A second approach to specific photochemotherapy, selective carcinoma cell photolysis (SCCP), relies on preferential accumulation of certain cationic PS by carcinoma cell mitochondria. We have evaluated several classes of cationic dyes, and in the case of N,N′‐bis‐(2‐ethyl‐1,3‐dioxolane)‐krypto‐cyanine (EDKC) and some of its analogs, have demonstrated highly selective killing of human squamous cell, bladder and colon carcinoma cells in vitro. In isolated mitochondria, EDKC uptake and fluorescence depended on membrane potential, and the dye specifically photosensitized damage to Complex I in the electron transport chain. N,N′‐bis‐(2‐ethyl‐1,3‐dioxolane)‐kryptocyanine and some of its analogs accumulated within subcutaneous xenografts of human tumors in nude mice with tumor : skin ratios > 8. Photoirradiation caused significant inhibition of tumor growth, without cutaneous phototoxicity.
SINGLET OXYGEN GENERATING EFFICIENCY OF α‐TERTHIENYL and SOME OF ITS SYNTHETIC ANALOGUES*
Authors: Scaiano J. C. , MacEachern A. , Arnason J. T. , Morand P. , Weir D. 
Published: January 2008

AbstractThe singlet oxygen generating efficiency of several thiophenic compounds, including oc‐terthienyl (αT) and some of its synthetic analogues, has been determined using laser flash photolysis techniques. The method, which is based on the time‐resolved bleaching of 1,3‐diphenylisobenzofuran, led to relatively high efficiencies for all the substrates examined; for example the values were 0.86, 0.69 and 0.63 for αT, DBrαT and TNP, respectively in chloroform‐d at 293K. Our results also indicate that high intersystem crossing efficiencies must be a common characteristic in these compounds. The variations in singlet oxygen yields were found to be modest in comparison with changes in the biological activity of these compounds, therefore suggesting that other factors are also quite important in determining the latter.
A FLUORESCENCE IMAGING DEVICE FOR ENDOSCOPIC DETECTION OF EARLY STAGE CANCER – INSTRUMENTAL and EXPERIMENTAL STUDIES
Authors: Baumgartner R. , Fisslinger H. , Jocham D. , Lenz H. , Ruprecht L. , Stepp H. , Unsold E. 
Published: January 2008

Abstract Visible detection of early stage cancer labelled with the fluorescing porphyrin mixture of dihematoporphyrin‐ether and dihematoporphyrin‐ester (DHE) is often limited by a high and inhomogeneously distributed level of autofluorescence. A new imaging method for reducing autofluo‐rescence is described. The method uses alternating fluorescence excitation with laser light in the violet and blue spectral ranges. Subtraction of the corresponding fluorescence images results in contrast enhancement due to an effective reduction in the autofluorescence contribution. A prototype version of a highly sensitive fluorescence imaging device including a modified krypton ion laser, an image‐intensified solid‐state TV‐camera, a digital image‐processing system, and video recording and monitoring has been developed.Experiments performed with this fluorescence imaging system on a tumorous dog bladder showed that a dose of 0.2 mg DHE kg−1 body wt, which is far below the dose administered for photodynamic therapy (2‐5 mg kg−’body wt), is sufficient to give a high‐contrast fluorescence image. The corresponding excitation power density was about 1 W m−2. Photobleaching of DHE was observed during fluorescence detection at excitation power densities exceeding 1 kW m−2. At these high excitation levels DHE fades out nearly completely within 0.25 min.
CLOSURE OF EXPERIMENTAL SUBRETINAL NEOVASCULAR VESSELS WITH DIHEMATOPORPHYRIN ETHER AUGMENTED ARGON GREEN LASER PHOTOCOAGULATION
Authors: Thomas Edgar L. , Langhofer Mikayo 
Published: January 2008

Abstract Natural history studies of patients with macular subretinal neovascularization as a complication of age‐related macular degeneration have shown a poor visual outcome, with 77% losing more than 4 lines of vision and 64% losing 6 lines at 24 months after presentation. The Macular Photocoagulation Study, a randomized clinical trial of selected cases of extramacular subretinal neovascularization has proven argon laser photocoagulation therapy to be effective in reducing visual loss. Unfortunately, many patients with macular subretinal neovascularization were excluded from this study because of the risk of laser damage to the surrounding retina and choroid.We have developed a potentially more efficacious and safe treatment for experimental subretinal neovascularization in the cynomolgus monkey using a combination of dihematoporphyrin ether pre‐treatment and sub‐threshold argon green laser photocoagulation. Closure of the subretinal neovascular complex was attained with reduced destruction to the surrounding retina and choroid. Our data have potential import for improved treatment in humans of macular subretinal neovascularization which lie beneath the foveal avascular zone. This preliminary study suggests the photosensitivity of the vasculature of the subretinal neovascular complex to laser photoradiation may be increased selectively by the use of dihematoporphyrin ether.
PHOTOBLEACHING OF PHOTOFRIN II AS A MEANS OF ELIMINATING SKIN PHOTOSENSITIVITY*
Authors: Boyle D. G. , Potter W. R. 
Published: January 2008

AbstractOne of the effects of using Photofrin II as a sensitizer in clinical photodynamic therapy is skin photosensitivity. Avoiding the harmful effect of this photosensitivity typically requires the patient to remain indoors during daylight hours for 4 weeks post injection. Photosensitivity can last up to 8 weeks. A possible method of quickly eliminating skin photosensitivity is the use of photobleaching to eliminate the DHE (dihematoporphyrin ether, the active agent in Photofrin II) from the skin. The Photofrin II was used as supplied (Photomedica, Raritan, NJ) and will be referred to as DHE.We report a series of experiments using Swiss mice which demonstrate the ability to reduce the period of photosensitivity to 1 week. The Swiss mice received 5 mg kg‐1 DHE intraperitoneal. Beginning at 24 h post injection they were given daily increasing light doses starting with 18 J cm‐2 (at 630 nm). Only the left hind feet were treated with light. At 7 days post injection both hind feet were treated with 135 J cm‐2. The pretreated left foot showed no reaction to this treatment whereas the right foot reacted as strongly as control mice which had received no pretreatment with light. The control mice were also injected 7 days prior to treatment.As a check for tolerance animals received a second injection of 5 mg kg‐1 DHE intraperitoneally 96 h after the conclusion of the bleaching protocol. Twenty‐four h later the left hind foot (previously desensitized by light) reacted to 135 J cm‐2 as strongly as controls which had received the 5 mg kg‐1 of DHE but no pretreatment.
INHIBITION OF THE IMMUNE RESPONSE TO ALLOANTIGEN IN THE RAT BY EXPOSURE TO ULTRAVIOLET RADIATION
Authors: Magee Mitchell J. , Kripke Margaret L. , Ullrich Stephen E. 
Published: January 2008

Abstract—Exposure of mice to ultraviolet radiation (UV) followed by alloantigcn sensitization can suppress the immune response to that alloantigen. In order to assess the applicability of using UV‐induced immunosuppression in organ transplantation, the effectiveness of UV in prolonging the survival of vascularized organ allografts must be determined. Because, for technical reasons, rats are better suited than mice for such experiments, we first wanted to determine whether UV suppresses the immune response of inbred rats to alloantigens. The data presented here demonstrate that exposure of rats to UV (115–129 kJ/m2) prior to alloantigenic sensitization decreases the mixed lymphocyte response to alloantigen. The depression of the proliferative response to alloantigen was selective in that spleen cells from the UV‐treated rats could respond to mitogenic stimulation. In contrast to previous results with mice, suppressor cells could not be demonstrated in the spleens of the UV‐treated rats. In addition, UV treatment after sensitization inhibited the response to alloantigen. These data suggest that treatment of the recipient with UV before or after alloantigenic sensitization may provide a novel method of inhibiting immune responses to allogeneic antigens.
LOCAL SUPPRESSION OF CONTACT HYPERSENSITIVITY IN MICE BY A MONOFUNCTIONAL PSORALEN PLUS UVA RADIATION
Authors: Alcalay Joseph , Ullrich Stephen E. , Kripke Margaret L. 
Published: January 2008

Abstract—Monofunctional psoralens, plus UVA radiation are not erythemogenic and are less mutagenic than bifunctional psoralens plus UVA radiation. Thus, they have received considerable attention in recent years as potential therapeutic agents for various skin diseases. The purpose of this study was to examine the immunologic side effects following treatment of mice with a monofunctional psoralen plus UVA radiation. We report that angelicin plus UVA radiation suppressed the induction of contact hypersensitivity to dinitrofluorobenzene. This decreased immune response was associated with the presence of splenic suppressor cells that transferred suppression to normal recipients. Treatment with angelicin and UVA radiation also decreased the number of Thy‐1+ and Ia+ dendritic epidermal cells in the treated site. We conclude that although this monofunctional psoralen is not phototoxic, it has immunosuppressive activity in mice.
ELICITATION OF SPREADING DEPRESSION BY ROSE BENGAL PHOTODYNAMIC ACTION
Authors: Netto Marialia , Martins‐Ferreira Hiss 
Published: January 2008

Abstract—Spreading depression refers to a slowly propagating depression of the ordinary electrical activity of the nervous tissue. It can be elicited by different types of physical or chemical non‐specific stimuli. Various evidences suggest that transient alterations of cell membranes are involved. For this reason, and considering the action of free radicals on cell membranes, the elicitation of the reaction by dye photoactivation has been investigated. Isolated chick retina superfused in the dark with Ringer solution was able to regularly exhibit spreading depression when submitted to 1 µ,M rose bengal pulse of 5 min in duration, followed by 2.1 104 to 4.2 times 104 Jm‐2 light pulse. The phenomenon was monitored either by visual inspection of the light‐scattering milky wave that accompanies the reaction or by recording its characteristic slow voltage variation. The reaction was not triggered if the retina, superfused with the dye, was (a) maintained in the dark; (b) illuminated with red light (3.75 times 102 to 2.25 times 104 Jm‐2), or (c) stimulated by white light but superfused with nitrogen‐saturated solutions. It is concluded that, under the present conditions, the elicitation of spreading depression is contingent on the photoactivation of rose bengal in the presence of oxygen.
SPECTROSCOPIC STUDIES OF CUTANEOUS PHOTOSENSITIZING AGENTS‐XIV. THE SPIN TRAPPING OF FREE RADICALS FORMED DURING THE PHOTOLYSIS OF HALOGENATED SALICYLANILIDE ANTIBACTERIAL AGENTS
Authors: Chignell Colin F. , Sik Robert H. 
Published: January 2008

Abstract—Several antibacterial halogenated salicylanilides, including 3,3′,4′,5‐tetrachlorosalicylanilide (TCSA) and 3,4′,5‐tribromosalicylanilide (TBSA) are known to cause photoallergy. We have carried out photochemical and spin trapping studies to determine whether free radicals may be involved in the photoallergic response. Irradiation (λ > 300 nm) of TCSA in buffered (pH 7.4) 50% ethanol resulted in the rapid loss of the 3‐chloro atom, followed by the much slower release of 5‐ and then the 4′‐chloro atoms to give 3′‐chlorosalicylanilide as a stable photoproduct. Under the same conditions TBSA successively lost the 3‐, 5‐ and 4′‐bromine atoms to give salicylanilide. When TCSA or TBSA were irradiated (λ= 356 nm) in buffered (pH 7.4) 50% ethanol containing 2‐methyl‐2‐nitrosopropane (MNP) only solvent‐derived free radicals were detected. However, irradiation (λ= 356 nm) of TCSA and MNP in 0.1 N NaOH generated an ESR spectrum consisting of a broad triplet (aN= 15.6 G).This spectrum was attributed to the adduct formed by the reaction of MNP with the aryl radical generated by the loss of a chlorine atom from the sterically hindered 3‐(or 4′‐)‐position. Under the same conditions TBSA initially generated a broad triplet (aN= 15.5 G) similar to that observed for TCSA. However, upon further irradiation a 21‐line spectrum (aN= 14.4 G, a2H= 2.0 G and a2H= 0.9 G) appeared. Since the same ESR spectrum was obtained by irradiating 4′‐bromosalicylanilide, the spectrum must be generated by an adduct formed by reaction of MNP with an aryl radical derived from loss of the 4′‐bromine atom of TBSA. Irradiation (λ= 356 nm) of TBSA, glutathione and the spin trap 5,5‐dirrrethyl‐l‐pyrroline‐N‐oxide (DMPO) yielded the glutathione thiyl adduct of DMPO. Irradiation of (λ= 356 nm) TCSA, MNP and glycylglycine resulted in the trapping of a carbon‐centered radical derived from hydrogen abstraction from the backbone methylene of the C‐terminal glycine residue. These studies demonstrate that photo‐irradiation of TCSA or TBSA generates highly reactive aryl radicals, which can react with peptides to form secondary radicals. Thein vivoreaction of secondary protein radicals with the primary aryl radicals from TCSA or TBSA would result in the covalent binding of the salicylanilides to skin proteins to give molecules with antigenic potential.
THE RELATIONSHIP BETWEEN MALIGNANT MELANOMA OF SKIN AND EXPOSURE TO SUNLIGHT
Authors: Lee John A. H. 
Published: January 2008

Abstract–Malignant melanomas of the skin are becoming more common. Earlier diagnosis has led to better individual prognoses, but this has not prevented the death rate in the population from rising. This paper brings up‐to‐date studies on the etiology of malignant melanoma, and supplements various fuller but earlier reviews.Melanoma risk is increased in lightly pigmented people who burn in the sun and do not tan well. People with an increased number of nevi are also at increased risk. Latitude of residence is important, risk in white populations increasing with distance from the poles. Phenotypic factors can over‐ride location, so that Mediterranean people have lower rates than Scandinavians. Melanomas are concentrated on sites exposed by clothing, but this concentration is not as strong as for the other skin cancers. Migrants to sunny climates are at less risk than similar people born locally, provided that they migrated as adults. Outdoor work carries only a small excess risk of malignant melanoma, in contrast to the other skin tumors. Melanomas are commoner, and kill more often, among people of high socioeconomic status than low.The two most detailed contemporary reconciliations of these pieces of evidence are based on the ideas that intense brief exposure is the critical factor, or that exposure in childhood is of major importance.With the expected changes in the global concentration of ozone in the stratosphere, it is necessary to estimate the relationship between the intensity of sunlight and melanoma risk.
RESOLUTION OF TWO EMISSION SPECTRA FOR TRYPTOPHAN USING FREQUENCY‐DOMAIN PHASE‐MODULATION SPECTRA
Authors: Lakowicz Joseph R. , Jayaweera Ranjith , Szmacinski Henryk , Wiczk Wieslaw 
Published: January 2008

Abstract–We describe a novel application of frequency‐domain fluorometry which allows resolution of the decay times and emission spectra of samples which display multi‐exponential decay kinetics. This method does not require any previous knowledge about the decay times or any assumptions about the shape of the emission spectra. We record the wavelength‐dependent phase angles and modulations (phase angle and modulation spectra) using a number of light modulation frequencies. The data are analyzed by non‐linear least‐squares to recover the underlying spectra and their associated decay times.Phase and modulation spectra (PM Spec) were used to recover the emission spectra associated with the two decay times of tryptophan at pH = 7 (0.54 and 3.44 ns). The emission spectra of these components are centered at 340 and 355 nm, respectively, with the amplitude of the 0.54 ns component contributing 6% to the total eirnssion. These results are in agreement with previous time‐resolved studies by Szabo and Rayner [J. Am. Chem. Soc.102, 554–563 (1980)]. Control experiments were performed on mixtures of N‐acetyl‐L‐tryptophanamide (NATA) and PPD, which demonstrate our ability to recover the spectra and decay times from two component mixtures. NATA itself displayed a single decay time and only one emission spectrum.
METALLOPURPURINS and LIGHT: EFFECT ON TRANSPLANTABLE RAT BLADDER TUMORS and MURINE SKIN
Authors: Morgan A. R. , Garbo G. M. , Keck R. W. , Eriksen L. D. , Selman S. H. 
Published: January 2008

AbstractPurpurins are modified chlorins with photodynamic properties. Their strong absorption in the red region of the visible spectrum makes them candidates for use in photodynamic cancer therapy. A series of metal derivatives of the free base purpurins have been synthesized and shown to cause tumor necrosis in transplantable tumors when exposed to visible light. In the following set of experiments, the effects of two metallo‐derivatives (tin and zinc) of two purpurins, octaethylpurpurin (NT2) and etiopurpurin (ET2), and light on the N‐{4‐(5‐nitro‐2‐furyl)‐2‐thiazolyl}formamide transplantable tumors in Fischer CDF(F344)/CrlBr rats were studied. The photodynamic activity was assessed by a short term assay using tumor dry weight 12 days after purpurin‐PDT as a criterion of response. From these experiments it appears that SnET2>SnNT2>ZnET2>ZnNT2 in photodynamic activity. SnET2 was further characterized by attempting to determine the time interval after systemic injection at which maximum therapeutic effect occurred. These studies shown that 24 h after metallopurpurin injection was the optimum time for treatment of tumors with visible light. In a final set of experiments, the effect of solar light on the skin of hairless mice injected with SnET2 was found to be much less injurious than with hematoporphyrin derivative.
HEMOPROTEIN(S) MEDIATE BLUE LIGHT DAMAGE IN THE RETINAL PIGMENT EPITHELIUM*
Authors: Pautler E. L. , Morita M. , Beezley D. 
Published: January 2008

AbstractIn order to elucidate the mechanisms of blue light damage on ocular tissues, the transepithelial transport, electrical characteristics and ultrastructural properties of irradiated isolated bovine retinal pigment epithelium (RPE) were investigated. Blue light (430 nm) irradiation at 20 mW/cm2 significantly reduced the transepithelial potential and short circuit current of RPE. During blue light exposure, a decrease in chloride transport was observed, and this decrease appeared to be closely coupled to changes in the electrical properties of the pigment epithelium. A decrease in leucine transport was also noted, but the effect required10–30 min of exposure to be manifested on some occasions. Utilizing the observed depolarizing effect of blue light, an action spectrum was determined which encompasses the absorption spectrum of the oxidized and reduced forms of cytochrome c oxidase. O2 uptake studies on isolated pigment epithelial cells verified the reduction of respiration by exposure to blue light, which is observed in other cells. Ultrastructural studies revealed that the major cytopathology observed up to 60 min after blue light exposure was a blistering of the mitochondria which progressed to a swollen, disrupted state within the post irradiation period of 1 h. Comparison of these results with those of other studies suggests that the mechanism of UV‐A damage differs substantially from that of blue light.
In vivo TUMOR OXYGEN TENSION MEASUREMENTS FOR THE EVALUATION OF THE EFFICIENCY OF PHOTODYNAMIC THERAPY
Authors: Tromberg B. J. , Orenstein A. , Kimel S. , Barker S. J. , Hyatt J. , Nelson J. S. , Berns M. W. 
Published: January 2008

Abstract—Among the sequence of events which occur during photodynamic therapy (PDT) are depletion of oxygen and disruption of tumor blood flow. In order to more clearly understand these phenomena we have utilized transcutaneous oxygen electrodes to monitor tissue oxygen disappearance. These results provide, for the first time, non‐invasive real‐time information regarding the influence of light dose on tissue oxygenation during irradiation. Measurements were conducted on transplanted VX‐2 skin carcinomas grown in the ears of New Zealand white rabbits. Rabbits were treated with Photofrin II and tumors were irradiated with up to 200 kj/m2(500 W/m2) of 630‐nm light. Substantial reductions in tumor oxygen tension were observed upon administration of as little as 20 kJ/m2. For a series of brief irradiations, oxygen tension was modulated by the appearance of laser light. Tissue oxygen reversibility appeared to be dependent upon PDT dose. Long‐term, irreversible tissue hypoxia was recorded in tumors for large (200 kJ/m2) fluences. These results suggest that transcutaneous oxygen tension may be useful as a general indicator of the effectiveness of PDT and as anin situpredictor of the energy required to elicit tumor damage.
EVIDENCE FOR THE FORMATION OF A CHLOROPHYLL a/ZEAXANTHIN COMPLEX IN LECITHIN LIPOSOMES FROM FLUORESCENCE DECAY KINETICS
Authors: Searle Geoffrey , Brody Seymour S. , Hoek Arie Van 
Published: January 2008

Abstract—The interaction of Chiawith zeaxanthin (Zea), which is an analogue of lutein, has been studied in soya bean lecithin liposomes using the fluorescence of Chi as monitor. The fluorescence emission spectrum at 4.2 K of Chiashowed characteristic changes in the presence of Zea: the emission maximum shifted from 688 nm to 680 nm, and a peak at 731 nm appeared. The fluorescence decay kinetics of Chiaalone could be described by the sum of two exponential components (T1,≅0.8 ns, T2≅2.5 ns). In the presence of Zea a component with a long lifetime, T≅5 ns, appeared with a large relative amplitude (40%). This indicated the formation of a Chla/Zea complex, in which Chla/Chlainteraction is negligible, presumably because of strong interaction between Chlaand Zea. The fluorescence anisotropy decay kinetics supported the hypothesis of the formation of a large Chlacontaining complex in the presence of Zea. A rotational correlation time, φ≅14 ns at 4°C and φ≅21 ns at 30°C, was found, which is distinctly larger than for samples containing Chlaonly. We interpret these results as further evidence for a strong interaction between Chlaand Zea in the hydrophobic environment of the lecithin liposomes. This interaction may also occur in the Chl‐proteins of the Chialblight‐harvesting complex of plant photosynthesis.