RESUMEN
Presented herein are the results of studying the optical density of water, blood, and venous-wall tissue for various-wavelength laser radiation, with determining the peaks of absorption of radiation by the above-mentioned media. The absorption peaks in water and blood correspond to wavelengths of 1,450 and 1,935 nm, respectively. Peaks of absorption in the venous-wall tissue are within the intervals equaling 650-950 nm, 1,445-1,455 nm, and more than 1,900 nm. Also determined was the optical density of the veins for the most frequently used in clinical practice wavelengths, i. e. 1,030 and 1,470 nm, with the calculation of the portion of the absorbed energy depending on thickness of the layer of the absorbing substance. Based on the obtained findings, a conclusion was drawn on better utilization of the energy of one-and-a-half-micron range laser radiation and on its preferable use for endovenous laser obliteration (EVLO).
Asunto(s)
Colágeno/efectos de la radiación , Procedimientos Endovasculares/métodos , Hemoglobinas/efectos de la radiación , Terapia por Láser , Rayos Láser , Venas/efectos de la radiación , Colágeno/fisiología , Diseño de Equipo , Hemoglobinas/fisiología , Humanos , Terapia por Láser/instrumentación , Terapia por Láser/métodos , Terapia por Láser/normas , Rayos Láser/clasificación , Rayos Láser/normas , Fenómenos Ópticos , Várices/patología , Venas/fisiologíaRESUMEN
Luminescence of singlet oxygen dimols (1O2)2 with the main spectral maximum at 703-706 nm and much weaker bands at 640 and 770-780 nm was studied using mechanical phosphoroscopes in aerobic solutions of the nonfluorescent photosensitizer phenalenone in CCl4 and C6F6 at relatively low radiant power. The spectrum of this luminescence resembles that of dimol luminescence, which we had detected previously in solutions of porphyrins and other compounds. It was shown that, in phenalenone solutions, the mechanism of dimol luminescence involves reaction of two 1O2 molecules and one ground-state pigment molecule. It is most likely that light is emitted by the dimol-pigment contact complexes formed as a result of collisions of 1O2 with metastable, probably triplet intermediates that result from reactions of 1O2 with pigment molecules. It is proposed that this luminescence mechanism is of general importance for many organic and biologically important systems where singlet oxygen is generated. However, a comparison with the literature data suggests that the luminescence of this type can be detected at relatively low rates of 1O2 generation. At high singlet oxygen generation rates, dimol luminescence with the main maximum at 635-637 nm dominates, which is likely caused by direct collisions of 1O2 molecules.
Asunto(s)
Aire , Colorantes/química , Fenalenos/química , Fármacos Fotosensibilizantes/química , Oxígeno Singlete/química , Presión Atmosférica , Tetracloruro de Carbono , Fluorocarburos , Luz , Luminiscencia , SolucionesRESUMEN
The low-temperature (77 K) phosphorescence of chlorophyll (Chl) in the reaction centres (D1D2-cyt b559-particles) and the core complexes of photosystem II isolated from higher plants was studied. Two phosphorescence spectral bands with the emission maxima at 950 and 977 nm, excitation maxima at 666 and 675-680 nm, and the lifetimes equal to 2 and 1.5 ms, respectively, were registered. The data indicate that the phosphorescence corresponds to the triplet Chl a molecules spatially separated from carotenoids. In samples treated by potassium ferricyanide and frozen under illumination by red light, the intensities of both bands were reduced, but the decrease of the short-wavelength 950-nm band was much more pronounced. This allows an assumption that the short-wavelength phosphorescence belongs to Chl a molecules, which are more accessible for ferricyanide because they are located on the surface of the chlorophyll-protein complexes, whereas the long-wavelength phosphorescence is emitted by the Chl molecules located inside the D1D2 heterodimer and therefore, is more protected by protein macromolecules.
Asunto(s)
Clorofila/química , Complejo de Proteína del Fotosistema II/química , Frío , Mediciones Luminiscentes , Cianuro de Potasio/químicaRESUMEN
The primary mechanisms for the photodynamic action of pigments and dyes, the principles of their division into mechanisms of type I and type II, and the role of these processes in biological systems are reviewed. Singlet oxygen is considered to be an indicator of the mechanisms of photodynamic reactions. The methods of its detection are described, which are based on the use of chemical traps, measurements of infrared phosphorescance at 1270 nm, and the registration singlet oxygen-sensitized delayed fluorescence caused by the summation of the energy of two singlet oxygen molecules by one dye molecule.
Asunto(s)
Luz , Oxígeno Singlete , Animales , Colorantes/química , Colorantes/efectos de la radiación , Historia del Siglo XIX , Historia del Siglo XX , Historia del Siglo XXI , Humanos , Luminiscencia , Fotoquímica/historia , Fármacos Fotosensibilizantes/química , Fármacos Fotosensibilizantes/efectos de la radiación , Pigmentos Biológicos/química , Pigmentos Biológicos/fisiología , Pigmentos Biológicos/efectos de la radiación , Oxígeno Singlete/historiaRESUMEN
The kinetic parameters of porphyrin-photosensitized formation and deactivation of singlet molecular oxygen (1O2) and their dependence on the concentration of the 1O2 quencher sodium azide were investigated in air-saturated water, ethanol, and aqueous micellar solutions of detergents using time-resolved measurements of oxygen phosphorescence under pulsed laser excitation. The lifetimes of 1O2 formation and deactivation and the rate constants of 1O2 quenching by sodium azide were determined. It was shown that, with no azide in the solutions, the rise in phosphorescence intensity after the laser flash corresponded to the kinetics of energy transfer from the porphyrin triplet molecules to oxygen, while the decay kinetics corresponded to the kinetics of 1O2 deactivation. In the presence of detergent, a considerable increase in the 1O2 lifetime was observed, which is likely due to the localization of 1O2 molecules mostly in lipophilic micelles and not in the water phase. If relatively high azide concentrations were used, the lifetime of the porphyrin triplet state did not change but the 1O2 lifetime decreased to values similar to those in living cells. In this case, the inversion of the phosphorescence kinetic phases was observed. The rise corresponded to 1O2 deactivation, and the decay, to the energy transfer from triplet porphyrin to oxygen. The data suggest that, in living cells, 1O2 molecules are also located mainly in lipophilic structures and the 1O2 lifetime determines the kinetics of the phosphorescence rise after the laser pulse.
Asunto(s)
Detergentes/química , Porfirinas/química , Oxígeno Singlete/química , Agua , Cinética , Luminiscencia , Fármacos Fotosensibilizantes/química , Azida Sódica , SolucionesRESUMEN
The effective photogeneration of singlet molecular oxygen (1O2) by porphyrins (coproporphyrin I; 2,4-bi (alpha-methoxyethyl) deuteroporphyrin IX and cyclopanten-coproporphyrin I) conjugated with antibodies (mouse monoclonal IgG and IgM and human gamma-globulin) have been observed with the direct luminescence method of 1O2 detection. Absolute quantum yields of 1O2 formation by the conjugates have been determined. The data suggest that porphyrin-antibody conjugates are promising for the use as drugs in photodynamic tumor treatment.
Asunto(s)
Inmunotoxinas/farmacología , Oxígeno , Fotoquimioterapia , Porfirinas/farmacología , Animales , Anticuerpos Monoclonales/administración & dosificación , Anticuerpos Monoclonales/uso terapéutico , Humanos , Inmunotoxinas/uso terapéutico , Terapia por Láser , Ratones , Fotoquímica , Porfirinas/uso terapéutico , Oxígeno Singlete , Soluciones , AguaRESUMEN
The photodynamic action of a number of carboxylic porphyrins and their covalent conjugates with specific monoclonal IgM antibodies on a human lung adenocarcinoma cell line was studied. All the conjugates showed strong phototoxicity which did not correspond with the phototoxicity of the free porphyrins. Absolute quantum yields of singlet oxygen photogeneration by the porphyrins and their conjugates were obtained and compared with the phototoxicity of the compounds.
Asunto(s)
Anticuerpos Antineoplásicos/administración & dosificación , Oxígeno/metabolismo , Fotoquimioterapia/métodos , Porfirinas/farmacología , Fármacos Sensibilizantes a Radiaciones/farmacología , Células Tumorales Cultivadas/efectos de los fármacos , Adenocarcinoma/inmunología , Adenocarcinoma/patología , Antígenos de Neoplasias/inmunología , Humanos , Inmunoglobulina M/administración & dosificación , Neoplasias Pulmonares/inmunología , Neoplasias Pulmonares/patología , Oxidación-Reducción , Porfirinas/administración & dosificación , Porfirinas/efectos de la radiación , Fármacos Sensibilizantes a Radiaciones/administración & dosificación , Oxígeno Singlete , Relación Estructura-ActividadRESUMEN
The photosensitized luminescence of singlet molecular oxygen has been studied in aqueous and alcoholic solutions of hematoporphyrin IX (HP) and di- and oligomeric components of "hematoporphyrin derivative" (photofrin II) which is known to be used as a drug in photodynamic tumor therapy. The quantum yields of 1O2 generation (gamma delta) by these compounds have been determined. It was found that the highest gamma delta values are characteristic of alcoholic and micellar detergent aqueous solutions. In detergent-free aqueous solutions containing mainly associated porphyrin molecules, gamma delta is much lower (5-30%), polymeric photofrin components being considerably less active than HP. Both localization of porphyrins in hydrophobic loci and high photosensitizing activity in lipid phase are supposed to play the key role in tumor photodestruction.
Asunto(s)
Hematoporfirinas , Oxígeno/análisis , Fotoquimioterapia , Éter de Dihematoporfirina , Hematoporfirinas/uso terapéutico , Humanos , Mediciones Luminiscentes , Neoplasias/tratamiento farmacológicoRESUMEN
With the use of mechanical phosphoroscope the "universal" delayed emission has been found in aerobic solutions of different sensitizers in CCl4. The spectrum of this emission has the main maximum at 703 nm. The luminescence intensity is proportional to the square of the intensity of the exciting light. Removal of oxygen or addition of 10% of acetone led to disappearance of the luminescence. At equal intensities of singlet oxygen generation relative intensities of the 1272 and 703 nm bands differed by several orders of magnitude in solutions of different sensitizers. The energy migration from the molecules responsible for the luminescence to bacteriopheophytin and phtalocyanine has been observed. The luminescence is interpreted as dimol emission of solvated singlet molecular oxygen activated by sensitizer molecules.
Asunto(s)
Luminiscencia , Oxígeno , Oxígeno Singlete , SolucionesRESUMEN
Synthetic DOPA-melanin and natural screening pigments--sepiomelanin and ommochromes are shown to quench the luminescence of singlet molecular oxygen (1O2) in aqueous (D2O, pD = 7.5-8.1) solutions. The rate constants of 1O2 quenching are found to be equal to (1.2 +/- 0.6) 10(8) M-1 s-1 for monomeric units in DOPA-melanin and to (3 +/- 1) 10(6) M-1 s-1 for ommochromes. The data suggest that screening is not the only function of melanins, which may play a role of inhibitors of photodynamic damage in living tissues.
Asunto(s)
Melaninas/farmacología , Oxígeno , Fenotiazinas/farmacología , Pigmentos Biológicos/farmacología , Animales , Fotoquímica , Oxígeno SingleteRESUMEN
It is shown that kinurenine derivatives, harmane (beta-carboline) and tetracycline hydrochloride known as photosensitizers of cataractogenesis in lens produce luminescence of singlet molecular oxygen (1O2) under photoexcitation in air saturated aqueous (D2O) solution. The quantum yields of the 1O2 generation by these substances are determined. The data obtained by this direct 1O2 determination technique suggest that 1O2 might take part in cataractogenesis.
Asunto(s)
Cristalino/metabolismo , Oxígeno/metabolismo , Catarata/etiología , Catarata/metabolismo , Humanos , Cinética , Luminiscencia , Fotoquímica , Oxígeno SingleteRESUMEN
The ability of phycobilisomes (PBS) to photosensitize the reduction of methylviologen by dithiothreitol has been shown. This reaction has been studied in dependence on the structural integrity of PBS, nature and pH of the medium, and concentration of reagents. The action spectrum of the reaction has been measured, and its quantum yield has been detected. The quenching of PBS fluorescence by methylviologen has been studied. The maximum rate of electron transfer photosensitized by PBS is observed in 0.6 M phosphate buffer containing 30% of glycerine, pH 9.5. The saturation occurs at methylviologen concentration of 2 X 10(-4) M. Under these conditions the PBS activity reaches 0,3 mumol/mg PBS.h and increases 100 times after preliminary heating of the reaction mixture for 5 min. at 35 degrees C. The light in the range of 520-680 nm is active for the photosensitized reduction of methylviologen. The quantum yield of the reaction is about 2%. In structures phycobiliproteins are more effective sensitizers than in solutions. The highest activity is observed for the substructure of PBS which contains allophycocyanin B and allophycocyanin C (34S particle). The possible mechanisms of the reaction are under consideration.
Asunto(s)
Paraquat , Proteínas de Plantas , Ditiotreitol , Cinética , Complejos de Proteína Captadores de Luz , Oxidación-Reducción , Fotoquímica , Ficobilisomas , Ficocianina , TemperaturaRESUMEN
Absorption, fluorescence and excitation fluorescence spectra of pheophytin a have been measured in aqueous solutions of nonionic (Triton X-100), anionic (sodium lauryl sulphate) and cationic (Cetyl pyridinium chloride) detergents at different concentrations and pH after system relaxation. By measuring the second derivative and differential spectra, it has been shown, that if detergent concentrations are lower than critical micelles concentration, or if the detergent is completely absent, the pigment forms conglomerates containing both dimeric and monomeric forms with an efficient energy transfer between them. If detergent concentrations are higher than critical micelles concentration, pheophytin a localizes in detergent micelle in monomeric form at neutral and acidic pH, and allomerizes at alkaline pH. The spectral characteristics of pheophytin a dimers in the conglomerate and its monomers in micelles poorly (if at all) depend on the sign of the detergent molecule charge.
Asunto(s)
Clorofila , Detergentes , Feofitinas , Tensoactivos , Cetilpiridinio , Clorofila/análogos & derivados , Clorofila A , Concentración de Iones de Hidrógeno , Micelas , Octoxinol , Fotoquímica , Polietilenglicoles , Conformación Proteica , Dodecil Sulfato de Sodio , Soluciones , EspectrofotometríaRESUMEN
Phycobilisomes (PBS) isolated from Nostoc muscorum contain eight spectral forms of phycobiliproteins. PBS partially dissociated by osmotic or temperature shock, were separated into 42S and 34S particles by centrifugation in sucrose density gradient. The 42S particles are enriched with phycocyanin, the 34S ones--with allophycocyanin. The 42S particles dissociate to free pigments by repeated osmotic or temperature shock and the 34S ones dissociate to subparticles I and II having the constant pigments composition. The integrity of PBS and isolated substructures is controlled by the yield of energy transfer between pigment molecules. PBS from Nostoc muscorum was found to contain the rods of three different types. The model PBS containing different spectral forms of biliproteins is proposed.
Asunto(s)
Cianobacterias/análisis , Ficocianina/análisis , Ficoeritrina/análisis , Pigmentos Biológicos/análisis , Proteínas de Plantas/análisis , Fraccionamiento Celular , Centrifugación por Gradiente de Densidad , Cianobacterias/ultraestructura , Complejos de Proteína Captadores de Luz , Ficobilisomas , Proteínas de Plantas/aislamiento & purificación , EspectrofotometríaRESUMEN
Photosensitized luminescence of singlet (1 delta g) molecular oxygen with the maximum at 1272 nm has been found in solutions of psoralen, angelicin and 8-methoxypsoralen in CCl4. The luminescence excitation spectra, quantum yields of generation (gamma g) and rate constants of quenching (Kq) of 1 delta g by psoralens have been measured. The gamma g values 0,0055, 0,0026, 0,002 and Kq values 9 X 10(3), 11 X 10(3) and 12 X X 10(3) have been obtained for psoralen, angelicin and 8-methoxypsoralen, respectively. The role of 1 delta g in a photobiological action of psoralens is discussed.
Asunto(s)
Furocumarinas , Oxígeno , Fotoquímica , Ficusina , Metoxaleno , Oxígeno SingleteRESUMEN
Comparison of theoretically expected and experimental dependence of reactivation of the donor side of photosystem 2 (PS-2) on concentration of exogenic MnCl2 that was observed in PS-2 preparation after complete extraction of manganese was made. It is shown that in the absence of Mg2+ or bivalent cations of other metals (Me2+) the reactivation corresponds to the filling of a tetranuclear Mn-containing active center; in the presence of 3 microM Mg2+ or other Me2+ the reactivation takes place as a result of binding of two manganese atoms in the center. It is suggested that a tetranuclear manganese complex (which probably is responsible for the photosynthetic oxidation of water) functions in the donor side of PS-2; two of these four manganese atoms can be substituted by Mg2+ or other Me2+ without changing activity of the center.
Asunto(s)
Cloruros , Compuestos de Manganeso , Manganeso/metabolismo , Manganeso/farmacología , Fotosíntesis/efectos de los fármacos , Cinética , Matemática , Plantas/metabolismoRESUMEN
The influence of Mn on saturation curves of ESR spectra of Ph(-) and P(+)(680) at 1-200K in samples with different content of Mn has been studied. An analysis of these data and those on photoinduced changes of fluorescence yield of chlorophyll leads to the conclusion that the Mn-containing centre in Photosystem 2 is a cluster of 4 Mn atoms, two of which can be replaced by Mg(2+) or any other divalent metal. The distances between Mn Na Ph as well as between Mn and P(680) have been estimated.
Asunto(s)
Clorofila/metabolismo , Manganeso/metabolismo , Feofitinas/metabolismo , Espectroscopía de Resonancia por Spin del Electrón , Campos Magnéticos , Oxidación-Reducción , Pisum sativum , Procesos Fotoquímicos , TemperaturaRESUMEN
The rate constants (kox) of irreversible oxidation of chlorophylls and porphyrins by 1 delta g state of oxygen (1O2) have been determined. It has been shown that kox values are 1-5 orders of magnitude lower than the values of rate constants of quenching 1O2 (kq) with the same pigments. The correlation between kox and kq has been found. Its analysis allowed to conclude that oxidation proceeds via intermediate formation of a charge transfer complex between the pigments and 1O2. A kinetic scheme of the processes leading to physical and chemical quenching 1O2 with chlorophylls and porphyrins is proposed, its mathematical analysis is carried out. The results of this analysis can be used for a search of substances capable of effective quenching 1O2 without destruction of the quenchers. It is concluded that chlorophylls protect photosynthetic membranes from the destruction by 1O2, and some synthetic metal-porphyrins can be used as good protectors of different systems against photooxidation.
Asunto(s)
Clorofila/metabolismo , Oxígeno/metabolismo , Porfirinas/metabolismo , Cinética , Fotoquímica , Oxígeno SingleteRESUMEN
A photoinduced ESR signal is detected in the presence of 10(-2) M of dithionine in phycobilisomes and in fractions enriched in allophycocyanin B. The signal is characterized by the line width of 12G and g-factor of 2.004. It is demonstrated that the appearance of the free radicals is related to photoreduction of allophycocyanin B.
Asunto(s)
Ficocianina/metabolismo , Pigmentos Biológicos/metabolismo , Ditionita , Espectroscopía de Resonancia por Spin del Electrón , Radicales Libres , Fotólisis , FicobilisomasRESUMEN
The effect of high intensity (photosynthesis-saturating) light on the optical properties of the bacteriochlorophyll and the light-induced H+ uptake by R. rubrum chromatophores was studied. It was shown that under aerobic conditions illumination causes reversible inhibition (in the dark) of the chromatophore ability for the light-induced uptake of H+, a reversible inhibition of the photosynthetical reaction center function and irreversible bleaching of the antennal bacteriochlorophyll. A kinetic comparison of spectral effects and reversible changes in pH as well as the effects of atmospheric oxygen and exogenous electron donors suggests that inhibition of photoactivity of the chromatophores upon illumination is due to accumulation of oxidized bacteriochlorophyll in the reaction center.