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Hoffmann, R. A wiki for the life sciences where authorship matters. Nature Genetics (2008)
 
MeSH Review

Photons

 
 
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Disease relevance of Photons

 

High impact information on Photons

  • We measure the yields of nitrite ions, hydroxyl radicals and photons [6].
  • We demonstrate experimentally the onset of laser-like action for entangled photons, through the creation and amplification of the spin-1/2 and spin-1 singlet states consisting of two and four photons, respectively [7].
  • Invertebrate photoreceptors use the phosphoinositide signalling cascade, responding to single photons with so-called quantum bumps which sum to form the macroscopic response to light [8].
  • These receptors are activated by photons or small molecules such as neurotransmitters, and glycoprotein hormones [9].
  • The weakest pulse of light a human can detect sends about 100 photons through the pupil and produces 10-20 rhodopsin isomerizations in a small retinal area [10].
 

Biological context of Photons

  • Gene expression was sustained in the tumor for up to 3 weeks (7.3x10(4)+/-2x10(4) photons/ sec/cm2/steradian (p/sec/cm2/sr) on day 4 and 7.0x10(4)+/-4x10(4) p/sec/cm2/sr on day 21) [11].
  • However, the kinetics of PSII inactivation in nigericin-treated thylakoids upon exposure to photoinhibitory light ranging from 185 to 2650 micromol photons m-2 s-1 was strictly exponential [12].
  • Upon deletion of sll1213, a pleiotropic phenotype was obtained: when propagated at 0.5 micromol photons m(-2) s(-1), photomixotrophic growth of cells lacking sll1213 was poor [13].
  • Fed corals therefore displayed a higher rate of photosynthesis per unit area (P(g)(max)= 570+/-60 nmol O(2) cm(-2) h(-1) and I(k)=403+/-27 micro mol photons m(-2) s(-1)) [14].
  • Normal tissue responses studied were acute reaction of normal skin (all treatment modalities) and LD50 following irradiation of the upper abdomen (in test of photons + O2 at 1 or 3 ATA) [15].
 

Anatomical context of Photons

  • 4. We derive approximate analytical solutions for the electrical response of the photoreceptor to light, both for bright flashes (isotropic conditions) and for single photons (involving longitudinal diffusion of cyclic GMP in the outer segment) [16].
  • In this study, we irradiated rat cervical spinal cords with single doses of 24 Gy of 18 MV photons or 20 MeV electrons and measured the levels of plasminogen activators at days 2, 7, 30, 60, 90, 120, 130 and 145 after irradiation, using appropriate controls at each time [17].
  • The physiological properties of kainate receptors and the geometry of the rod axon terminal suggest that presynaptic GluR6/7 could provide a steady inward current to maintain consistent depolarization of the rod synapse in the long intervals between photons in the dark [18].
  • CONCLUSION: Fast neutron radiotherapy provides higher local control rates than a mixed beam and photons in advanced, recurrent or not completely resected adenoid cystic carcinoma of the major and minor salivary glands [19].
  • RESULTS: The mean aqueous flare was 6.3 photons/ms +/- 3.0 (SD) (range 4.0 to 12.2 photons/ms) 1 day postoperatively, with 64% of patients having normal aqueous flare values (<8.0 photons/ms) [20].
 

Associations of Photons with chemical compounds

  • This problem is eliminated by using a double-caged glutamate that requires absorption of two photons for conversion to active glutamate, resulting in a substantial improvement in spatial resolution over conventional caged glutamate [21].
  • Enzymes from various organisms contain two chromophore cofactors (FADH2 and either methenyltetrahydrofolate or 8-hydroxy-5-deazaflavin) that absorb the low-energy photons and initiate splitting of the cyclobutane ring by a radical mechanism [22].
  • Photolyases repair pyrimidine dimers in DNA by converting the light energy of 300- to 500-nm photons into chemical energy [22].
  • While chloride transport in halorhodopsin is mediated by a one-photon process, proton transport requires the absorption of two photons: one photon for formation of H410 and release of a proton, and one photon for photoisomerization of H410 and re-formation of H578 with concomitant uptake of a proton by the Schiff base [23].
  • Pumpkin leaves grown under high light (500-700 micromol of photons m-2.s-1) were illuminated under photon flux densities ranging from 6.5 to 1500 micromol.m-2.s-1 in the presence of lincomycin, an inhibitor of chloroplast protein synthesis [24].
 

Gene context of Photons

  • To better understand the role of PCNA after photon irradiation in vivo, using flow cytometry, we studied the immunochemical PCNA-staining in V79 cells after irradiation with 6-MeV photons with and without serum depletion and with and without low-dose pre-irradiation under different growth conditions [25].
  • Analysis of total RNA isolated from the two pine species grown in darkness or moderate light conditions (250 mumol photons m-2 s-1) showed no significance difference in the level of expression of the clpP gene [26].
  • Model measurements confirmed TOFA principles in systems with a high degree of photon scattering; rat images, which were constructed from the variable time delays experienced by a fixed fraction of early-arriving transmitted photons, revealed identifiable internal structure [27].
  • In the model organism Dunaliella salina (a green alga), growth under low light (100 mol of photons per m2 per sec) entails damage, degradation, and replacement of D1 every 7 hr [28].
  • After the lower Ca(2+) affinity and the 10-fold smaller absorption cross-section for photons in CP47 dimers is taken into account, the intrinsic rate constant for the rate-limiting calcium-dependent dark step is indistinguishable for the two systems [29].
 

Analytical, diagnostic and therapeutic context of Photons

References

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  2. Sll1717 affects the redox state of the plastoquinone pool by modulating quinol oxidase activity in thylakoids. Kufryk, G.I., Vermaas, W.F. J. Bacteriol. (2006) [Pubmed]
  3. Spinal cord dose reduction using an anterior 13 MeV electron field situated between a split anterior 60Co supraclavicular field. Mills, M.D., Fuller, L.M., Zagars, G.K., McNeese, M.D. Int. J. Radiat. Oncol. Biol. Phys. (1987) [Pubmed]
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  6. The energy efficiency of formation of photons, radicals and ions during single-bubble cavitation. Didenko, Y.T., Suslick, K.S. Nature (2002) [Pubmed]
  7. Stimulated emission of polarization-entangled photons. Lamas-Linares, A., Howell, J.C., Bouwmeester, D. Nature (2001) [Pubmed]
  8. Protein kinase C is required for light adaptation in Drosophila photoreceptors. Hardie, R.C., Peretz, A., Suss-Toby, E., Rom-Glas, A., Bishop, S.A., Selinger, Z., Minke, B. Nature (1993) [Pubmed]
  9. Human cytomegalovirus encodes three G protein-coupled receptor homologues. Chee, M.S., Satchwell, S.C., Preddie, E., Weston, K.M., Barrell, B.G. Nature (1990) [Pubmed]
  10. Low retinal noise in animals with low body temperature allows high visual sensitivity. Aho, A.C., Donner, K., Hydén, C., Larsen, L.O., Reuter, T. Nature (1988) [Pubmed]
  11. Bioluminescence imaging of systemic tumor targeting using a prostate-specific lentiviral vector. Iyer, M., Salazar, F.B., Wu, L., Carey, M., Gambhir, S.S. Hum. Gene Ther. (2006) [Pubmed]
  12. Model for the fluorescence induction curve of photoinhibited thylakoids. Vavilin, D.V., Tyystjärvi, E., Aro, E.M. Biophys. J. (1998) [Pubmed]
  13. Myxoxanthophyll is required for normal cell wall structure and thylakoid organization in the cyanobacterium Synechocystis sp. strain PCC 6803. Mohamed, H.E., van de Meene, A.M., Roberson, R.W., Vermaas, W.F. J. Bacteriol. (2005) [Pubmed]
  14. Interactions between zooplankton feeding, photosynthesis and skeletal growth in the scleractinian coral Stylophora pistillata. Houlbrèque, F., Tambutté, E., Allemand, D., Ferrier-Pagès, C. J. Exp. Biol. (2004) [Pubmed]
  15. Therapeutic gain factors for fractionated radiation treatment of spontaneous murine tumors using fast neutrons, photons plus O2(1) or 3 ATA, or photons plus misonidazole. Suit, H.D., Sedlacek, R., Silver, G., Hsieh, C.C., Epp, E.R., Ngo, F.Q., Roberts, W.K., Verhey, L. Radiat. Res. (1988) [Pubmed]
  16. A quantitative account of the activation steps involved in phototransduction in amphibian photoreceptors. Lamb, T.D., Pugh, E.N. J. Physiol. (Lond.) (1992) [Pubmed]
  17. Elevated levels of plasminogen activators in the pathogenesis of delayed radiation damage in rat cervical spinal cord in vivo. Sawaya, R., Rayford, A., Kono, S., Ang, K.K., Feng, Y., Stephens, L.C., Rao, J.S. Radiat. Res. (1994) [Pubmed]
  18. Localization of kainate receptors to the presynaptic active zone of the rod photoreceptor in primate retina. Harvey, D.M., Calkins, D.J. Vis. Neurosci. (2002) [Pubmed]
  19. Radiotherapy for advanced adenoid cystic carcinoma: neutrons, photons or mixed beam? Huber, P.E., Debus, J., Latz, D., Zierhut, D., Bischof, M., Wannenmacher, M., Engenhart-Cabillic, R. Radiotherapy and oncology : journal of the European Society for Therapeutic Radiology and Oncology. (2001) [Pubmed]
  20. Short-term blood-aqueous barrier breakdown after implantation of the 1CU accommodative posterior chamber intraocular lens. Nguyen, N.X., Langenbucher, A., Huber, S., Seitz, B., Küchle, M. Journal of cataract and refractive surgery. (2002) [Pubmed]
  21. Chemical two-photon uncaging: a novel approach to mapping glutamate receptors. Pettit, D.L., Wang, S.S., Gee, K.R., Augustine, G.J. Neuron (1997) [Pubmed]
  22. The third chromophore of DNA photolyase: Trp-277 of Escherichia coli DNA photolyase repairs thymine dimers by direct electron transfer. Kim, S.T., Li, Y.F., Sancar, A. Proc. Natl. Acad. Sci. U.S.A. (1992) [Pubmed]
  23. Light-driven proton or chloride pumping by halorhodopsin. Bamberg, E., Tittor, J., Oesterhelt, D. Proc. Natl. Acad. Sci. U.S.A. (1993) [Pubmed]
  24. The rate constant of photoinhibition, measured in lincomycin-treated leaves, is directly proportional to light intensity. Tyystjärvi, E., Aro, E.M. Proc. Natl. Acad. Sci. U.S.A. (1996) [Pubmed]
  25. X-ray induced changes in immunostaining of proliferating cell nuclear antigen (PCNA) in V79 hamster fibroblasts. Lohr, F., Hof, H., Weber, K.J., Latz, D., Wenz, F. Strahlentherapie und Onkologie : Organ der Deutschen Röntgengesellschaft ... [et al]. (1998) [Pubmed]
  26. Identification and expression of the chloroplast clpP gene in the conifer Pinus contorta. Clarke, A.K., Gustafsson, P., Lidholm, J.A. Plant Mol. Biol. (1994) [Pubmed]
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  28. Photosystem II reaction center damage and repair cycle: chloroplast acclimation strategy to irradiance stress. Vasilikiotis, C., Melis, A. Proc. Natl. Acad. Sci. U.S.A. (1994) [Pubmed]
  29. Photoassembly of the manganese cluster and oxygen evolution from monomeric and dimeric CP47 reaction center photosystem II complexes. Büchel, C., Barber, J., Ananyev, G., Eshaghi, S., Watt, R., Dismukes, C. Proc. Natl. Acad. Sci. U.S.A. (1999) [Pubmed]
  30. Attenuation correction of thallium SPECT using differential attenuation of thallium photons. Hansen, C.L., Siegel, J.A. J. Nucl. Med. (1992) [Pubmed]
  31. Compton scatter image simulating jugular venous reflux. Yeh, E.L. J. Nucl. Med. (1982) [Pubmed]
  32. Carboplatin and radiotherapy in the treatment of head and neck cancer: six years' experience. Zamboglou, N., Schnabel, T., Kolotas, C., Achterrath, W., Strehl, H., Dalhäuser, S., Vogt, H.G., Lenaz, L., Schmitt, G. Semin. Oncol. (1994) [Pubmed]
  33. Multi-modality treatment of primary nonresectable intrahepatic cholangiocarcinoma with 131I anti-CEA--a Radiation Therapy Oncology Group Study. Stillwagon, G.B., Order, S.E., Klein, J.L., Leichner, P.K., Leibel, S.A., Siegelman, S.S., Fishman, E.K., Ettinger, D.S., Haulk, T., Kopher, K. Int. J. Radiat. Oncol. Biol. Phys. (1987) [Pubmed]
  34. Gadolinium neutron capture brachytherapy (GdNCB), a new treatment method for intravascular brachytherapy. Enger, S.A., Rezaei, A., af Rosenschöld, P.M., Lundqvist, H. Medical physics. (2006) [Pubmed]
 
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