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21.
Bortoletto D Goldberg M Horwitz N Mestayer MD Moneti GC Sharma V Shipsey IP Skwarnicki T Csorna SE Letson T Brock IC Ferguson T Artuso M Bebek C Berkelman K Blucher E Byrd J Cassel DG Cheu E Coffman DM Crawford G DeSalvo R DeWire JW Drell PS Ehrlich R Galik RS Gittelman B Gray SW Halling AM Hartill DL Heltsley BK Kandaswamy J Kowalewski R Kreinick DL Kubota Y Lewis JD Mistry NB Mueller J Namjoshi R Nandi S Nordberg E O'Grady C Peterson D Pisharody M Riley D Sapper M Silverman A Stone S Worden H 《Physical review letters》1989,62(21):2436-2439
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Shaw NM Blanis D Bodek A Budd H Coombes R Eno S Fry CA Harada H Ho YH Kim YK Kumita T Mori T Olsen SL Sill A Thorndike EH Ueno K Zheng HW Imlay R Kirk P Lim J McNeil RR Metcalf W Myung SS Cheng CP Gu P Li J Li YK Mao ZP Xu YT Zhu YC Abashian A Gotow K Hu K Low EH Mattson ME Naito F Piilonen L Sterner KL Lusin S Rosenfeld C Wang AT Wilson S Frautschi M Kagan H Kass R Trahern CG Breedon RE Kim GN Ko W Lander RL Maeshima K Malchow RL Smith JR Sparks K Williams MC Abe K Fujii Y Higashi Y Kim SK 《Physical review letters》1989,63(13):1342-1345
23.
Novel proline-thiazole based cyclopeptides were produced by cyclooligomerisation of an L-proline thiazole amino acid HCl in the presence of pentafluorophenyl diphenylphosphinate (FDPP) or diphenyl phosphorazidate (DPPA). 相似文献
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M S Patterson S J Madsen B C Wilson 《Journal of photochemistry and photobiology. B, Biology》1990,5(1):69-84
Singlet oxygen (1O2) is thought to be the cytotoxic agent in photodynamic therapy (PDT) with current photosensitizers. Direct monitoring of 1O2 concentration in vivo would be a valuable tool in studying biological response. Attempts were made to measure 1O2 IR luminescence during PDT of cell suspensions and two murine tumour models using the photosensitizers Photofrin II and aluminium chlorosulphonated phthalocyanine. Instrumentation was virtually identical to that devised by Parker in the one positive report of in vivo luminescence detection in the literature. Despite the fact that our treatments caused cell killing and tissue necrosis, we were unable to observe 1O2 emission under any conditions. We attribute this negative result to a reduction in 1O2 lifetime in the cellular environment. Quantitative calibration of our system allowed us to estimate that the singlet oxygen lifetime in tissue is less than 0.5 microsecond. Some technical improvements are suggested which would improve detector performance and perhaps make such measurements feasible. 相似文献
29.
A Study of the Uptake of Toluidine Blue O by Porphyromonas gingivalis and the Mechanism of Lethal Photosensitization 总被引:2,自引:1,他引:2
Manpreet Bhatti Alexander MacRobert Sajeda Meghji Brian Henderson Michael Wilson 《Photochemistry and photobiology》1998,68(3):370-376
The purpose of the study was to determine the distribution of the photosensitizer toluidine blue O (TBO) within Porphyromonas gingivalis and the possible mechanism(s) involved in the lethal photosensitization of this organism. The distribution of TBO was determined by incubating P. gingivalis with tritiated TBO (3H-TBO) and fractionating the cells into outer membrane (OM), plasma membrane (PM), cytoplasmic proteins, other cytoplasmic constituents and DNA. The percentage of TBO in each of the fractions was found to be, 86.7, 5.4, 1.9, 5.7 and 0.3%, respectively. The involvement of cytotoxic species in the lethal photosensitization induced by light from a helium-neon (HeNe) laser and TBO was investigated by using deuterium oxide (D2O), which prolongs the lifetime of singlet oxygen, and the free radical and singlet oxygen scavenger L-tryptophan. There were 9.0 log10 and 2 log10 reductions in the presence of D2O and H2O (saline solutions), respectively, at a light dose of 0.44 J (energy density = 0.22 J/cm2), suggesting the involvement of singlet oxygen. Decreased kills were attained in the presence of increasing concentrations of L-tryptophan. The effect of lethal photosensitization on whole cell proteins was determined by measuring tryptophan fluorescence, which decreased by 30% using 4.3 J (energy density = 4.3 J/ cm2) of light. Effects on the OM and PM proteins were determined by sodium dodecyl sulfate polyacrylamide gel electrophoresis. There was evidence of change in the molecular masses of several PM proteins and OM proteins compared to controls. There was evidence of damage to the DNA obtained from irradiated cells. Scanning electron microscopic studies showed that there was coaggre-gation of P. gingivalis cells when sensitized and then exposed to laser light. These results suggest that lethal photosensitization of P. gingivalis may involve changes in OM and/or PM proteins and DNA damage mediated by singlet oxygen. 相似文献
30.
I. Alex Vitkin Joshua Woolsey Brian C. Wilson R. Rox Anderson 《Photochemistry and photobiology》1994,59(4):455-462
Abstract The optical properties and the thermal diffusivity of natural cuttlefish ( Sepia officinalis ) melanin have been measured. The optical absorption and scattering properties of melanin particles were determined at 580 nm and 633 nm, using photometric and photothermal techniques. For the photometric studies, the absorption and the transport scattering coefficients were determined from the measurements of diffuse reflectance and transmittance. The scattering anisotropy was obtained from an additional measurement of the total attenuation coefficient and independently obtained by goniometry. For photothermal studies, pulsed photothermal radiometry was used to deduce the absorption and transport scattering coefficients via a model based on optical diffusion theory. Pulsed photothermal radiometry was also used to provide the thermal diffusivity of solid melanin pressed pellets. 相似文献