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Red Fluorescence (red + fluorescence)
Selected AbstractsJC-1, a sensitive probe for a simultaneous detection of P-glycoprotein activity and apoptosis in leukemic cellsCYTOMETRY, Issue 3 2006Driss Chaoui Abstract Background JC-1 probe has been successfully used for the analysis of either apoptosis or P-glycoprotein (P-gp) activity. Therefore, we wanted to see if JC-1 could also simultaneously assess both, P-gp activity and apoptosis, in acute myeloid leukemia (AML) cells. Methods P-gp activity was measured using JC-1 and compared to the results of the Rhodamine 123 (Rh 123) assay in P-gp negative and P-gp positive cell lines, and 12 AML samples. For apoptosis, spontaneous apoptosis, as well as, apoptosis induced by Cytosine Arabinosine and Homoharringtonine were analyzed. Both mitochondrial red fluorescence and cytoplasmic green fluorescence of JC-1 with and without a P-gp inhibitor (Cyclosporine A : CsA) were used for the identification of apoptotic cells, and this was compared to Annexin V/PI staining. Results (1) We found a good correlation between JC-1 and Rh 123 in viable cells. Even in a small population of viable cells, P-gp positive cells emitting low red fluorescence, gained on red fluorescence after P-gp inhibition with CsA permitting an evaluation of P-gp activity. (2) We found a good correlation between the Annexin V/PI staining and JC-1 (P < 0.0001) in the assessment of apoptotic cells. Most importantly, the apoptotic cells could be distinguished by the loss of red fluorescence and the increase of green fluorescence without any change after P-gp inhibition with CsA. Conclusions JC-1 can simultaneously evaluate two important parameters involved in drug resistance in AML cells, P-gp activity and apoptosis. © 2006 International Society for Analytical Cytology [source] Analysis of mitochondria by capillary electrophoresis: cardiolipin levels decrease in response to carbonyl cyanide 4-(trifluoromethoxy) phenylhydrazoneEUROPEAN JOURNAL OF LIPID SCIENCE AND TECHNOLOGY, Issue 9 2010Wenfeng Zhao Abstract Cardiolipin is an important phospholipid present in the inner membrane of mitochondria. It plays a critical role in adenosine triphosphate (ATP) synthesis mediated by oxidative phosphorylation. Exposure of HepG2 cells to carbonyl cyanide 4-(trifluoromethoxy) phenylhydrazone (FCCP) caused the inhibition of ATP synthesis and the depolarization of mitochondria. Capillary electrophoresis with laser-induced fluorescence (CE-LIF) analysis of fluorescent mitochondrion-selective probe 10-N-nonyl acridine orange (NAO) labeled mitochondria was employed to in situ estimate the cardiolipin levels under FCCP-induced de-energization of mitochondria. NAO, stoichiometriclly bound to cardiolipin at a 1:1 or 2:1 molar ratio (NAO/cardiolipin), emitted green and red fluorescence, respectively. Green fluorescence was chosen for cardiolipin content analysis because it was more intense than red fluorescence. A significant decrease in the cardiolipin content, up to 11% of the control, was evident when the ATP content and mitochondrial membrane potential (MMP) correspondingly decreased. These related findings suggested that CE-LIF may provide a sensitive strategy to determine cardiolipin content in response to exposure to chemical uncouplers. This reinforces the hypothesis that alterations in ATP synthesis and MMP have a close association with cardiolipin content, which correlated tightly with mitochondrial membrane assembly and activity. [source] Light-Triggered Self-Assembly of a Spiropyran-Functionalized Dendron into Nano-/Micrometer-Sized Particles and Photoresponsive Organogel with Switchable FluorescenceADVANCED FUNCTIONAL MATERIALS, Issue 1 2010Qun Chen Abstract The synthesis, self-assembly, and spectroscopic investigations of spiropyran (SP)-functionalized dendron 1 are reported. Under UV light irradiation, assembly of 1 into nano-/microparticles occurs due to the transformation of the closed form of SP into the open merocyanine (MC) form. The formation of these nano-/microparticles is confirmed by transmission electron microscopy (TEM) and dynamic light scattering (DLS) experiments in addition to the confocal laser scanning microscopy (CLSM) measurements. These nano-/microparticles exhibit relatively strong red emission. It is interesting to note that the direct cooling of the toluene/benzene solution of 1 to 0,°C leads to gel formation. Multivalent ,,, interactions due to the dendron in 1 may be the driving-force for the gelation. The UV light irradiation cannot destroy the gel phase, and in fact, the gel,gel transition is successfully realized. The purple-blue gel exhibits relatively strong red fluorescence; moreover, the fluorescence can be reversibly switched by alternating UV and visible light irradiation. The results clearly indicate that the MC form after aggregation becomes more stable and fluorescent. [source] Synthesis, light emission, and photovoltaic properties of perylene-containing polyacetylenesJOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 6 2008Jianli Hua Abstract Perylene (Py)-containing polyacetylenes with different skeleton structures [HCC(C6H4)CO2Py]n (P1), [HCC(CH2)8CO2Py]n (P2), and {[(C6H5) CC(CH2)9NH2]co[(C6H5)CC(CH2)9Py]}n (P3) are synthesized in satisfactory yields by Rh-catalyzed polymerization (for P1 and P2) and polymer reaction (for P3). All the polymers are soluble and possess high molecular weights (Mw up to 2.8 × 105). Their structures and properties are characterized and evaluated by IR, NMR, UV, TGA, PL, and photovoltaic (PV) analyses. The polymers are thermally stable, losing little of their weights when heated to 330 °C. When their solutions are irradiated, their perylene pendants emit intense red fluorescence at 610 nm. PV cells with a configuration of ITO/PEDOT:PSS/polymer/LiF/Al are fabricated, which show maximum current density of 10.3 ,A/cm2. The external quantum efficiency is sensitive to the polymer structure, with P3 exhibiting the highest value of 0.23%. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 2025,2037, 2008 [source] The First Half-Century of Laser DevelopmentLASER TECHNIK JOURNAL, Issue 4 2010How a solution that once was looking for a problem has become part of everyday life The laser was born on May 16, 1960 at Hughes Research Laboratories in Malibu, California. Instead of enjoying the view of the Pacific from his new office window, Theodore Maiman closeted himself in a windowless lab, where he slipped a spring-shaped photographic flashlamp over a stubby ruby rod, then put the assembly inside a reflective cylinder. Firing pulses with higher and higher voltage through the lamp, he carefully studied oscilloscope traces of the rise and fall of the ruby's red fluorescence. Once the voltage exceeded 950 volts, the lamp flashed bright enough to excite the ruby above laser threshold. The red light suddenly flashed so bright that Maiman's colorblind assistant Irnee D'Haenens saw red light for the first time [1]! The instruments recorded what Maiman had predicted would happen above laser threshold , the pulse rose and fell faster, and the range of red wavelengths narrowed. This article provides an overview of the first 50 years of laser development as well as a brief outlook what's coming next. [source] Bacterial composition and red fluorescence of plaque in relation to primary and secondary caries next to composite: an in situ studyMOLECULAR ORAL MICROBIOLOGY, Issue 1 2008R. Z. Thomas Background/hypothesis:, Secondary caries has been suggested as the main reason for restoration replacement. We hypothesized that more caries-associated bacteria are found on composite resin restoration material, compared to sound tooth tissue. Methods:, Both restored and unrestored dentin and enamel samples were placed in a full denture of eight subjects for 20 weeks. The microbiological composition of approximal plaque and the association between caries-associated bacteria and red autofluorescence of dental plaque was studied. Every 4 weeks the specimens were microradiographed using transversal wavelength independent microradiography (T-WIM). After 1 and 20 weeks red fluorescence pictures and plaque samples were taken. Samples were cultured for total anaerobic counts, mutans streptococci, lactobacilli, candida and Actinomyces odontolyticus. Results:, Lesion depth in the dentin and enamel was positively associated with lactobacilli, and lesion depth in dentin was positively associated with A. odontolyticus, whereas no association was found between mutans streptococci and lesion depth. The red-fluorescent bacteria A. odontolyticus and lactobacilli did not correlate with red-fluorescent plaque, indicating that red fluorescence is probably not caused by a single species of these bacteria. After 20 weeks, a higher proportion of combined mutans streptococci and lactobacilli was found on restored tissue compared to non-restored tissue (P = 0.04). Conclusion:, The higher proportion of caries-associated bacteria on restored tissue indicates that the ecology on the surface of primary lesions differs from that on lesions next to composite, and that secondary caries next to composite may differ from the primary caries process. [source] Measurement of gradients of absorbed light in spinach leaves from chlorophyll fluorescence profilesPLANT CELL & ENVIRONMENT, Issue 12 2000T. C. Vogelmann ABSTRACT Profiles of chlorophyll fluorescence were measured in spinach leaves irradiated with monochromatic light. The characteristics of the profiles within the mesophyll were determined by the optical properties of the leaf tissue and the spectral quality of the actinic light. When leaves were infiltrated with 10,4M DCMU [3-(3,4-dichlorophenyl)-1, 1-dimethyl-urea] or water, treatments that minimized light scattering, irradiation with 2000 ,mol m,2 s,1 green light produced broad Gaussian-shaped fluorescence profiles that spanned most of the mesophyll. Profiles for chlorophyll fluorescence in the red (680 ± 16 nm) and far red (, > 710 nm) were similar except that there was elevated red fluorescence near the adaxial leaf surface relative to far red fluorescence. Fluorescence profiles were narrower in non-infiltrated leaf samples where light scattering increased the light gradient. The fluorescence profile was broader when the leaf was irradiated on its adaxial versus abaxial surface due to the contrasting optical properties of the palisade and spongy mesophyll. Irradiation with blue, red and green monochromatic light produced profiles that peaked 50, 100 and 150 ,m, respectively, beneath the irradiated surface. These results are consistent with previous measurements of the light gradient in spinach and they agree qualitatively with measurements of carbon fixation under monochromatic blue, red and green light. These results suggest that chlorophyll fluorescence profiles may be used to estimate the distribution of quanta that are absorbed within the leaf for photosynthesis. [source] Increased Apoptosis in Human Amnion is Associated with Labor at TermAMERICAN JOURNAL OF REPRODUCTIVE IMMUNOLOGY, Issue 5 2000CHAUR-DONG HSU PROBLEM: To characterize whether increased apoptosis in human amnion was associated with labor at term. METHOD OF STUDY: Human amnion were obtained from term patients with vaginal delivery (n=5) or who underwent elective Cesarean section (C/S) without labor (n=5). Apoptosis was performed by the TUNEL (Terminal dUTP Nuclear End Labeling) assay. All nucleated cells stained with propidium iodide in the amnion epithelial cells were identified in red fluorescence. TUNEL positive apoptotic nuclei were identified in green fluorescence. Five random fields of each specimen were blindly counted by investigators. The percentage of apoptotic nuclei of total nuclei (apoptotic index) was calculated and compared between the two groups (25 microscopic fields for each group, respectively). RESULTS: Patients with term labor had a significantly higher mean apoptotic index in amnion epithelial cells than that with elective C/S without labor (27.3±4.1% versus 3.6±1.6%, P<0.001). CONCLUSIONS: Our data indicate that apoptosis in human amnion is significantly increased and associated with labor at term. [source] Effect of moderate electric field frequency and growth stage on the cell membrane permeability of Lactobacillus acidophilusBIOTECHNOLOGY PROGRESS, Issue 1 2009Laleh Loghavi Abstract Changes in growth kinetics and metabolic activity of microorganisms under the presence of a moderate electric field (MEF) have been hypothesized as being due to temporary permeabilization of cell membranes. We investigated herein the effects of frequency and growth stage on cell membrane permeabilization of Lactobacillus acidophilus OSU 133 during MEF fermentation. Cells were stained with two fluorescent nucleic acid stains: the green, nonselective, cell membrane permeable SYTO 9, and the red, cell membrane impermeable propidium iodide (PI). Fluorescence exhibition post-treatment was assessed using fluorescence microscopy. Total plate counting was done to determine whether or not the permeabilized population represented live cells. Fermentation treatments investigated were conventional (control) and MEF (2 V/cm, 45, 60, 1,000, 10,000 Hz) at 30°C. Studies were conducted at 45 Hz for lag, exponential, and stationary phases of growth. Low frequency MEF treated cells exhibited significantly greater numbers of red cell counts than conventional treatments; further, no significant differences existed in viable counts between MEF and conventional treatments, suggesting that the red counts represent permeabilized live cells. MEF treatments at the early stage of bacterial growth at 45 Hz exhibited the maximum permeabilization followed by treatments at 60 Hz. MEF treated samples at frequencies higher than 60 Hz did not exhibit red fluorescence. Cells at lag phase showed the greatest susceptibility to permeabilization followed by those at exponential phase. No evidence of electroporation was observed during the stationary phase. To our knowledge, these observations provide the first evidence that cell membrane permeabilization occurs under the presence of electric fields as low as those under MEF. © 2009 American Institute of Chemical Engineers Biotechnol. Prog., 2009 [source] Topical photodynamic therapy with 5-aminolaevulinic acid does not induce hair regrowth in patients with extensive alopecia areataBRITISH JOURNAL OF DERMATOLOGY, Issue 5 2000R. Bissonnette Background,Photodynamic therapy (PDT) is a new modality involving the administration of a photosensitizer, or photosensitizer precursor, followed by its activation with light to generate a therapeutic effect. 5-Aminolaevulinic acid (ALA) is a photosensitizer precursor that is transformed by cells into protoporphyrin IX (PpIX), which can in turn be activated by red light. Objectives,To investigate the effect of PDT in alopecia areata (AA). Methods,In six patients with extensive AA, topical ALA lotion at 5%, 10% and 20% as well as the vehicle lotion alone were applied separately to different scalp areas, followed 3 h later by exposure to red light at each treatment session. Results,No significant hair growth was observed after 20 twice-weekly treatment sessions. A significant increase in erythema and pigmentation was observed for the three concentrations of ALA lotion vs. the vehicle, implying that a phototoxic PDT effect was achieved in the skin. In vivo fluorescence spectroscopy in one patient showed an increase in red PpIX fluorescence 3 h after ALA application followed by a decrease after light exposure. On fluorescence microscopy, bright red fluorescence was present in the epidermis and sebaceous glands, but not in the inflammatory infiltrate surrounding the hair follicle following ALA application. Conclusions,PDT was ineffective in the treatment of AA. [source] White-Light-Emitting DNA (WED)CHEMISTRY - A EUROPEAN JOURNAL, Issue 37 2009Reji Varghese Dr. White knight: A DNA-based energy donor,acceptor couple exhibits red fluorescence in the single strand that changes to white light upon duplex formation in a completely reversible manner (see picture). [source] | ||||||||||||||||