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Loupy, Alexandre, and Christophe Legendre. "From Mean Fluorescence Intensity to C1q-Binding." Transplantation 99, no. 6 (June 2015): 1107–8. http://dx.doi.org/10.1097/tp.0000000000000700.
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Jansen, Sanne, Daniel De Bruin, Simon Strackee, Ed Van Bavel, Ton Van Leeuwen, Mark I. Van Berge Henegouwen, and Suzanne Gisbertz. "PS01.186: QUANTITATIVE PERFUSION EVALUATION AFTER GASTRIC TUBE RECONSTRUCTION USING FLUORESCENCE IMAGING." Diseases of the Esophagus 31, Supplement_1 (September 1, 2018): 102–3. http://dx.doi.org/10.1093/dote/doy089.ps01.186.
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Abstract Background Poor fundus perfusion is seen as the major factor for the development of anastomotic necrosis, leakage and strictures. Quantitative imaging of tissue perfusion during reconstructive surgery, therefore, may reduce the incidence of complications. Imaging the fluorescense of intravenously administered fluorophores is an optical, non-contact method to image blood flow in real-time. However, quantitative parameters for perfusion evaluation are stil lacking. The objective of this study is to test fluorescence imaging derived quantitative parameters for perfusion evaluation of the gastric tube during surgery and to correlate these parameters to patient outcome in terms of anastomotic leakage. Methods This study included 22 patients (October 2015 - June 2016). Indocyanine green (ICG) was injected intravenously and the fluorescense intensity of the gastric tube was imaged for 2–3 minutes. At 4 locations, quantitative analysis of the fluorescent intensity over time was performed to obtain perfusion related parameters: the maximal intensity, mean slope and influx timepoint. These parameters were tested for significant differences between the four perfusion areas of the gastric tube (from normal to decreased perfusion) with a repeated ANOVA test. Furthermore, these parameters and the distance of the end of the gastroepiploic artery to the fundus and distance of the demarcation of the fluorescent signal to the fundus were compared with patient outcome in terms of anastomotic leakage development. Results The fluorescent signal could be detected in all analyzed patients (n = 20). Maximal intensity, mean slope and influx timepoint were significantly different between the base of the gastric tube and the fundus (P < 0.0001). While the distance of the watershed and the demarcation of ICG to the fundus varied between patients, the distance of the demarcation of ICG to the fundus was significantly higher in the three patients who developed anastomotic leakage (P < 0.0001). No allergic reactions on ICG were witnessed. Conclusion Intra-operative fluorescence imaging is feasible to visualize perfusion quantitatively in gastric-tube surgery, using the parameters maximal intensity, mean slope and influx timepoint. A low slope and a large distance between the fluorescence demarcation and the fundus were seen in patients who developed anastomotic leakage and could therefore allow for early risk stratification of necrosis. Disclosure All authors have declared no conflicts of interest.
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A. Wells, Denise, and Michael R. Loken. "Flow cytometric mean fluorescence intensity: The biophysics behind the number." Leukemia Research 32, no. 6 (June 2008): 845–46. http://dx.doi.org/10.1016/j.leukres.2007.10.002.
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Maryamchik, E., X. Zheng, X. Zhang, R. Machietto, C. Finn, N. Giacobbe, M. Quant, S. Choudhari, S. Kadauke, and Y. Wang. "Low CD45 mean fluorescence intensity predicts poor Post-Thaw CD34 cell viability." Cytotherapy 22, no. 5 (May 2020): S63. http://dx.doi.org/10.1016/j.jcyt.2020.03.093.
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Zhao, J., Y. X. Fu, T. Yang, Z. Y. Shen, and C. L. Wu. "Prediction of Complement-Binding Capacity of HLA Antibodies Based on Mean Fluorescence Intensity." Transplantation Proceedings 48, no. 6 (July 2016): 2235–40. http://dx.doi.org/10.1016/j.transproceed.2016.04.018.
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Wu, Chang Ni, and Yang Chen. "Lanthanide Complex-Polyethylenimine Conjugate: A Highly Luminescent Probe for Time-Resolved Fluorescence Analysis." Applied Mechanics and Materials 108 (October 2011): 212–16. http://dx.doi.org/10.4028/www.scientific.net/amm.108.212.
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Macromolecular polymer polyethylenimine (PEI) modified by many luminescent lanthanide complexes was prepared and purified. The spectral properties and lifetime of this fluorescence probe were measured. The mean number of lanthanide complexes per PEI molecule was measured and calculated. The fluorescent intensity of a macromolecule modified with lanthanide complexes is 6-fold as high as that of a lanthanide complex molecule.
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Saipetch, K., and C. Yoshimura. "Importance of correcting for fluorescence quenching in fluorescence-based prediction of trihalomethane formation potential." Water Supply 19, no. 6 (March 4, 2019): 1677–85. http://dx.doi.org/10.2166/ws.2019.039.
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Abstract Fluorescence excitation–emission matrix (EEM) spectroscopy is often used to determine the levels of trihalomethane (THM) precursors in natural organic matter. However, humic substances are known to quench the fluorescence of amino acids and proteins. To date, none of the EEM-based models for predicting THM formation potential (THMFP) have explicitly accounted for these quenching effects. Thus, we investigated the importance of correcting for fluorescence quenching during THMFP prediction. Fluorescence titration experiments revealed that the correction improved the accuracy of THM prediction. EEM-based models using the corrected fluorescence intensity displayed the highest accuracy (R2 > 0.99; mean absolute error 8.1 μg/L and 13.9 μg/L for chloroform and bromoform, respectively) among models using individual parameters of EEM intensity, dissolved organic carbon (DOC), ultraviolet absorbance at 254 nm (UV254), specific UV254 (SUVA254) and differential ultraviolet absorbance at 272 nm (ΔUV272). Thus, EEM-based models require both the fluorescence intensity of a humic-like component and the corrected fluorescence intensity of a protein-like component for accurate THMFP prediction, for both chlorination and bromination processes. We also found it to be unnecessary to combine DOC with EEM intensity in terms of prediction accuracy, as long as the fluorescence quenching correction is applied.
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Wang, Jun Sheng, You Nan Song, Jin Yang Sun, Hui Chu, Jin Hu Jiang, Xin Xiang Pan, Ye Qing Sun, and Dong Qing Li. "A Microfluidic Cytometer for Quantitative Evaluation of Radiation Dose by γ-H2AX." Applied Mechanics and Materials 522-524 (February 2014): 1119–22. http://dx.doi.org/10.4028/www.scientific.net/amm.522-524.1119.
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Evaluation of radiation dose is very important for the detection of radiation damage. γ-H2AX is a popular biological dosimeter to evaluate the radiation effect. Typically, bulky and expensive commercial flow cytometers are used to detect γ-H2AX. This paper presents a miniaturized and highly sensitive cytometer using a microfluidic chip for evaluating the radiation dose by detecting the mean immunofluorescence intensity of γ-H2AX. A compact optical focusing system and a shift-phase differential amplifier are designed to improve the detection sensitivity. Sample lymphocyte cells are stained by FITC fluorescent dye after being irradiated by UVC. Comparison experiments between the developed miniature cytometer and a commercial flow cytometer were conducted under different radiation doses. The developed microfluidic cytometer can also demonstrate a good linear correlation between the measured fluorescence intensity and the irradiation dose with a detection limit similar to that of the commercial flow cytometer. The developed cytometer can evaluate quantitatively the radiation dose by the mean fluorescence intensity of γ-H2AX with a significantly smaller amount of blood samples than a commercial flow cytometer.
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Frénoy, J. P., F. Emmanuel, and J. M. Salmon. "Use of quantitative image microfluorometry to follow fluorescent ricin internalization in single living cells." Journal of Histochemistry & Cytochemistry 42, no. 5 (May 1994): 627–33. http://dx.doi.org/10.1177/42.5.8157934.
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We used microspectrofluorometry and videomicrofluorometry to follow the binding and internalization of fluorescein-labeled toxic lectin ricin in living Zajdela hepatoma cells. Microspectrofluorometry showed that when ricin was specifically labeled on its B-chain with one molecule of fluorescein (ABF), its fluorescence spectrum did not alter during its binding to the cell surface and subsequent internalization. This enabled us to use image analysis to follow cell internalization of labeled ricin. Accordingly, we measured the appropriate fluorescent cell parameters, comprising total fluorescence intensity, cell surface area, mean fluorescence intensity and its standard error, and used the measurements for mono- and biparametric studies of cell fluorescence distribution. The results showed that (a) ricin binds two different subpopulations of Zajdela hepatoma cells, (b) Zajdela hepatoma cells internalize ricin rapidly and after a relatively stable period of 1-2 hr, internalization starts again at 4 hr, and (c) the distribution of intracellular fluorescence is heterogeneous and ABF accumulates in certain cellular localizations. Our results demonstrate that quantitative microfluorometry is an effective and interesting approach for real-time studies of macromolecule internalization in living cells.
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Baker, A., R. Inverarity, and D. Ward. "Catchment-scale fluorescence water quality determination." Water Science and Technology 52, no. 9 (November 1, 2005): 199–207. http://dx.doi.org/10.2166/wst.2005.0319.
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Chemical water quality determinants and river water fluorescence were determined on the River Tyne, northeast England. Statistically significant relationships between nitrate (r=0.87), phosphate (r=0.80), ammonia (r=0.70), biochemical oxygen demand (BOD) (r=0.85) and dissolved oxygen (r=−0.65) and tryptophan-like fluorescence intensity were observed. The strongest correlations are between tryptophan-like intensity and nitrate and phosphate, which in the Tyne catchment derive predominantly from point and diffuse source sewage inputs. The correlation between BOD and the tryptophan-like fluorescence intensity suggests that this fluorescence centre is related to the bioavailable or labile dissolved organic matter pool. The weakest correlations are observed between tryptophan-like fluorescence intensity and ammonia concentration and dissolved oxygen. The weaker correlation with ammonia is due to good ammonia treatment within the wastewater treatment plants within the catchment, and that with dissolved oxygen due to the natural aeration of the river such that this is not a good indicator of water quality. Mean annual tryptophan-like fluorescence intensity, measured by both bench and portable spectrometers, agrees well with the General Water Quality Assessment as determined by the England and Wales environmental regulators, the Environment Agency.
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Zimnyakov, Dmitry, Elena Isaeva, Anna Isaeva, and Sergey Volchkov. "Band-Limited Reference-Free Speckle Spectroscopy: Probing the Fluorescent Media in the Vicinity of the Noise-Defined Threshold." Applied Sciences 10, no. 5 (February 29, 2020): 1629. http://dx.doi.org/10.3390/app10051629.
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A method of reference-free speckle spectroscopy based on the statistical analysis of intensity spatial fluctuations of the spectrally-selected multiple-scattered fluorescence radiation is examined in the case of the finite-band spectral selection of fluorescence light emitted by the laser-pumped random medium, and detection conditions far from the ideal case. Intensity fluctuations are recorded during point-to-point scanning of the surface of a random multiple-scattering medium, which is characterized by the dependences of the second- and third-order statistical moments of intensity on the wavelength of detected spectrally selected light. In turn, the statistical moments of intensity fluctuations are determined by the average propagation path of fluorescent radiation in the medium. This makes it possible to analyze the features of the light-medium interactions at a scale of the order of the transport mean free path of radiation propagation in the medium. Depending on the spectral selection conditions, the method is applicable for characterizing micro- or nano-structured fluorescent layers with thicknesses from tens of micrometers to several millimeters. In the examined case, the finite-band spectral selection results in the values of coherence length of the detected fluorescence radiation compared with the ensemble-averaged absolute value of the path-length difference between the stochastically interfering and spectrally selected partial contributions to the fluorescence field. In addition, non-ideal detection conditions (usage of a multimode optical fiber in the light-collecting unit) cause additional strong damping of the detected speckle intensity fluctuations. These factors lead to a remarkable suppression of spatial fluctuations of the fluorescence intensity in the course of spatially- and spectrally-resolved surface scanning of the laser-pumped probed random medium. Nevertheless, with appropriate procedures of the intrinsic noise reduction and data correction, the obtained spectral dependencies of the normalized third-order statistical moment of the band-limited fluorescence intensity clearly indicate the fluorescence propagation features in the probed multiple-scattering random media (such as a strong influence of the scattering strength and multiple self-absorption–re-emission events on the average propagation path of light in the medium).The possibilities of noise reduction and data correction in the case of applying the band-limited reference-free spectroscopic instrumentation with low spectral and spatial resolution are illustrated by the experimental results obtained using the Rhodamine-6G-doped and continuous wave (CW)-laser-pumped layers of the densely packed titania and silica particles.
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Claisse, Guillaume, Lena Absi, Eric Alamartine, Nicolas Maillard, and Christophe Mariat. "SO003RELATIONSHIP BETWEEN MEAN FLUORESCENCE INTENSITY AND C1Q/C3D-FIXING CAPACITIES OF ANTI-HLA ANTIBODIES." Nephrology Dialysis Transplantation 31, suppl_1 (May 2016): i2. http://dx.doi.org/10.1093/ndt/gfw117.03.
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Claisse, Guillaume, Lena Absi, Fabrice Cognasse, Eric Alamartine, Christophe Mariat, and Nicolas Maillard. "Relationship between Mean Fluorescence Intensity and C1q/C3d-fixing capacities of anti-HLA antibodies." Human Immunology 78, no. 4 (April 2017): 336–41. http://dx.doi.org/10.1016/j.humimm.2017.02.003.
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Shooshtari, Parisa, Edgardo S. Fortuno, Darren Blimkie, Miao Yu, Arvind Gupta, Tobias R. Kollmann, and Ryan R. Brinkman. "Correlation analysis of intracellular and secreted cytokines via the generalized integrated mean fluorescence intensity." Cytometry Part A 77A, no. 9 (July 13, 2010): 873–80. http://dx.doi.org/10.1002/cyto.a.20943.
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Lau, Darryl, Shawn L. Hervey-Jumper, Susan Chang, Annette M. Molinaro, Michael W. McDermott, Joanna J. Phillips, and Mitchel S. Berger. "A prospective Phase II clinical trial of 5-aminolevulinic acid to assess the correlation of intraoperative fluorescence intensity and degree of histologic cellularity during resection of high-grade gliomas." Journal of Neurosurgery 124, no. 5 (May 2016): 1300–1309. http://dx.doi.org/10.3171/2015.5.jns1577.
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OBJECT There is evidence that 5-aminolevulinic acid (ALA) facilitates greater extent of resection and improves 6-month progression-free survival in patients with high-grade gliomas. But there remains a paucity of studies that have examined whether the intensity of ALA fluorescence correlates with tumor cellularity. Therefore, a Phase II clinical trial was undertaken to examine the correlation of intensity of ALA fluorescence with the degree of tumor cellularity. METHODS A single-center, prospective, single-arm, open-label Phase II clinical trial of ALA fluorescence-guided resection of high-grade gliomas (Grade III and IV) was held over a 43-month period (August 2010 to February 2014). ALA was administered at a dose of 20 mg/kg body weight. Intraoperative biopsies from resection cavities were collected. The biopsies were graded on a 4-point scale (0 to 3) based on ALA fluorescence intensity by the surgeon and independently based on tumor cellularity by a neuropathologist. The primary outcome of interest was the correlation of ALA fluorescence intensity to tumor cellularity. The secondary outcome of interest was ALA adverse events. Sensitivities, specificities, positive predictive values (PPVs), negative predictive values (NPVs), and Spearman correlation coefficients were calculated. RESULTS A total of 211 biopsies from 59 patients were included. Mean age was 53.3 years and 59.5% were male. The majority of biopsies were glioblastoma (GBM) (79.7%). Slightly more than half (52.5%) of all tumors were recurrent. ALA intensity of 3 correlated with presence of tumor 97.4% (PPV) of the time. However, absence of ALA fluorescence (intensity 0) correlated with the absence of tumor only 37.7% (NPV) of the time. For all tumor types, GBM, Grade III gliomas, and recurrent tumors, ALA intensity 3 correlated strongly with cellularity Grade 3; Spearman correlation coefficients (r) were 0.65, 0.66, 0.65, and 0.62, respectively. The specificity and PPV of ALA intensity 3 correlating with cellularity Grade 3 ranged from 95% to 100% and 86% to 100%, respectively. In biopsies without tumor (cellularity Grade 0), 35.4% still demonstrated ALA fluorescence. Of those biopsies, 90.9% contained abnormal brain tissue, characterized by reactive astrocytes, scattered atypical cells, or inflammation, and 8.1% had normal brain. In nonfluorescent (ALA intensity 0) biopsies, 62.3% had tumor cells present. The ALA-associated complication rate among the study cohort was 3.4%. CONCLUSIONS The PPV of utilizing the most robust ALA fluorescence intensity (lava-like orange) as a predictor of tumor presence is high. However, the NPV of utilizing the absence of fluorescence as an indicator of no tumor is poor. ALA intensity is a strong predictor for degree of tumor cellularity for the most fluorescent areas but less so for lower ALA intensities. Even in the absence of tumor cells, reactive changes may lead to ALA fluorescence.
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Yin, Wei, Chun Wang, Kuohai Fan, Na Sun, Yaogui Sun, and Hongquan Li. "In vitro observation: the GFP-E. coli adhering to porcine erythrocytes can be removed by porcine alveolar macrophages." PeerJ 7 (March 8, 2019): e6439. http://dx.doi.org/10.7717/peerj.6439.
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Although the activation of pathogen phagocytosis via complement system has been studied, erythrocyte-phagocyte interactions in pigs are not clearly understood. Therefore, we sought to investigate the ability of porcine erythrocytes to clear immune complexes (ICs) by using laser confocal microscopy and flow cytometry to observe the immune adhesion of porcine erythrocytes to fluorescent bacilli and the immune presentation process of transferring fluorescent bacilli to macrophages. Isolated porcine alveolar macrophages (PAMs) had uniform morphology and size, and a survival rate of 97.2%. The phagocytosis rate was 98.8%. After WT E. coli was labeled with Fluorescein Isothiocyanate (FITC), the bacteria showed a bright green fluorescence, and the labeling rate was 92.3%. When laser confocal microscopy was utilized to observe the co-incubation system of porcine erythrocytes, PAM, and fluorescent E. coli, the fluorescence intensity of bacilli decreased with increasing observation time and even disappeared. Flow Cytometry examination showed that the average fluorescence intensity of PAMs co-incubated with porcine erythrocytes adhered to WT-E. coli-FITC, was significantly higher than that of normal PAMs. Furthermore, when porcine erythrocytes adhered to WT E. coli were incubated with PAMs, the surface mean fluorescence intensity of porcine erythrocytes was significantly higher than that of the blank control group. This shows that PAMs can competitively bind to the oposinized E. coli adhered to the surface of porcine erythrocytes, and these oposinized pathogens can enter macrophages by the process of phagocytosis, which promoting the internalization of ICs or pathogens. During this process, the physical morphology of porcine erythrocytes was not damaged, but the levels of its main functional protein CR1-like were reduced.
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Kamp, Marcel A., Philipp Slotty, Bernd Turowski, Nima Etminan, Hans-Jakob Steiger, Daniel Hänggi, and Walter Stummer. "Microscope-Integrated Quantitative Analysis of Intraoperative Indocyanine Green Fluorescence Angiography for Blood Flow Assessment: First Experience in 30 Patients." Operative Neurosurgery 70, suppl_1 (August 1, 2011): ons65—ons74. http://dx.doi.org/10.1227/neu.0b013e31822f7d7c.
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Abstract BACKGROUND: Intraoperative measurements of cerebral blood flow are of interest during vascular neurosurgery. Near-infrared indocyanine green (ICG) fluorescence angiography was introduced for visualizing vessel patency intraoperatively. However, quantitative information has not been available. OBJECTIVE: To report our experience with a microscope with an integrated dynamic ICG fluorescence analysis system supplying semiquantitative information on blood flow. METHODS: We recorded ICG fluorescence curves of cortex and cerebral vessels using software integrated into the surgical microscope (Flow 800 software; Zeiss Pentero) in 30 patients undergoing surgery for different pathologies. The following hemodynamic parameters were assessed: maximum intensity, rise time, time to peak, time to half-maximal fluorescence, cerebral blood flow index, and transit times from arteries to cortex. RESULTS: For patients without obvious perfusion deficit, maximum fluorescence intensity was 177.7 arbitrary intensity units (AIs; 5-mg ICG bolus), mean rise time was 5.2 seconds (range, 2.9-8.2 seconds; SD, 1.3 seconds), mean time to peak was 9.4 seconds (range, 4.9-15.2 seconds; SD, 2.5 seconds), mean cerebral blood flow index was 38.6 AI/s (range, 13.5-180.6 AI/s; SD, 36.9 seconds), and mean transit time was 1.5 seconds (range, 360 milliseconds-3 seconds; SD, 0.73 seconds). For 3 patients with impaired cerebral perfusion, time to peak, rise time, and transit time between arteries and cortex were markedly prolonged (>20, >9 , and >5 seconds). In single patients, the degree of perfusion impairment could be quantified by the cerebral blood flow index ratios between normal and ischemic tissue. Transit times also reflected blood flow perturbations in arteriovenous fistulas. CONCLUSION: Quantification of ICG-based fluorescence angiography appears to be useful for intraoperative monitoring of arterial patency and regional cerebral blood flow.
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O’Leary, J. G., H. Kaneku, B. M. Susskind, L. W. Jennings, M. A. Neri, G. L. Davis, G. B. Klintmalm, and P. I. Terasaki. "High Mean Fluorescence Intensity Donor-Specific Anti-HLA Antibodies Associated With Chronic Rejection Postliver Transplant." American Journal of Transplantation 11, no. 9 (June 14, 2011): 1868–76. http://dx.doi.org/10.1111/j.1600-6143.2011.03593.x.
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Grajek, Hanna, Jacek Kubicki, Ignacy Gryczyński, Jerzy Karolczak, Grażyna Żurkowska, Agnieszka I. Piotrowicz-Cieślak, and Piotr Bojarski. "Effect of Dimer Structure and Inhomogeneous Broadening of Energy Levels on the Action of Flavomononucleotide in Rigid Polyvinyl Alcohol Films." International Journal of Molecular Sciences 22, no. 14 (July 20, 2021): 7759. http://dx.doi.org/10.3390/ijms22147759.
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The results of time-resolved fluorescence measurements of flavin mononucleotide (FMN) in rigid polyvinyl alcohol films (PVA) demonstrate that fluorescence intensity decays are strongly accelerated in the presence of fluorescent dimers and nonradiative energy transfer processes. The fluorescence decay originating both from H and J dimer states of FMN was experimentally observed for the first time. The mean fluorescence lifetimes for FMN dimers were obtained: τfl = 2.66 ns (at λexc = 445 nm) and τfl = 2.02 (at λexc = 487 nm) at λobs = 600 nm and T = 253 K from H and J state of dimers, respectively. We show that inhomogeneous orientational broadening of energy levels (IOBEL) affects the shape of the fluorescence decay and leads to the dependence of the average monomer fluorescence lifetime on excitation wavelength. IOBEL affected the nonradiative energy transfer and indicated that different flavin positioning in the protein pocket could (1) change the spectroscopic properties of flavins due to the existence of “blue” and “red” fluorescence centers, and (2) diminish the effectiveness of energy transfer between FMN molecules.
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Swatland, H. J. "Optical properties of turkey pectoralis muscle affecting detection of connective tissue fluorescence." Canadian Journal of Animal Science 81, no. 1 (March 1, 2001): 25–31. http://dx.doi.org/10.4141/a00-053.
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A dual-channel probe was used to detect fluorescence (excitation 365 nm, emission 400 to 550 nm) and reflectance (550 nm) in turkey pectoralis muscles (n= 157). All fluorescence peaks had matching reflectance peaks, but not vice versa. Thus, some reflectance peaks originated from non-fluorescent structures in the muscle. Electrical impedance was used to assess fluid distribution. Electrical capacitance was correlated (P< 0.01) with areas under probe signals (r= 0.19 for both fluorescence and reflectance). In a subset of samples (n= 45), the reflectance of initially polarized light was used to assess light scattering. Consistent relationships between probe signals and the reflectance of initially polarized light were detected. When polarized light was parallel with the longitudinal axes of muscle fibers, and when the analyzer was parallel with the polarizer, reflectance was correlated (P< 0.01) with the incidence of fluorescence and reflectance peaks (R= 0.58 and R= 0.59, respectively), with mean peak intensity (R= 0.51 and R= 0.49, respectively), and with mean half-peak width (R= 0.48 and R= 0.56, respectively). The spectral distribution of correlations indicated that myoglobin as well as differences in light scattering affected the probe detection of connective tissue fluorescence. Thus, bulk optical properties of muscle affected probe detection of connective tissue fluorescence. Key words: Connective tissue, fluorescence, turkey meat
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Miller, William G., Maria T. Brandl, Beatriz Quiñones, and Steven E. Lindow. "Biological Sensor for Sucrose Availability: Relative Sensitivities of Various Reporter Genes." Applied and Environmental Microbiology 67, no. 3 (March 1, 2001): 1308–17. http://dx.doi.org/10.1128/aem.67.3.1308-1317.2001.
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ABSTRACT A set of three sucrose-regulated transcriptional fusions was constructed. Fusions p61RYTIR, p61RYlac, and p61RYice contain thescrR sucrose repressor gene and the promoterlessgfp, lacZ, and inaZreporter genes, respectively, fused to the scrY promoter from Salmonella enterica serovar Typhimurium. Cells ofErwinia herbicola containing these fusions are induced only in media amended with sucrose, fructose, or sorbose. While a large variation in sucrose-dependent reporter gene activity was observed in cells harboring all gene fusions, fusions to theinaZ reporter gene yielded a much wider range of activity and were responsive to lower levels of sucrose than eitherlacZ or gfp. The lacZreporter gene was found to be more efficient than gfp, requiring approximately 300-fold fewer cells for a detectable response over all concentrations of sucrose. Similarly, inaZ was found to be more efficient than lacZ, requiring 30-fold fewer cells at 1.45 μM sucrose and 6,100-fold fewer cells at 29 mM sucrose for a quantifiable response. The fluorescence of individual cells containing p61RYTIR was quantified following epifluorescence microscopy in order to relate the fluorescence exhibited by populations of cells in batch cultures with that of individual cells in such cultures. While the mean fluorescence intensity of a population of individual cells increased with increasing concentrations of sucrose, a wide range of fluorescence intensity was seen among individual cells. For most cultures the distribution of fluorescence intensity among individual cells was log-normally distributed, but cells grown in intermediate concentrations of sucrose exhibited two distinct populations of cells, one having relatively low fluorescence and another with much higher fluorescence. When cells were inoculated onto bean leaves, whole-cell ice nucleation andgfp-based biological sensors for sucrose each indicated that the average concentration of sucrose on moist leaf surfaces was about 20 μM. Importantly, the variation in green fluorescent protein fluorescence of biosensor cells on leaves suggested that large spatial variations in sugar availability occur on leaves.
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Kostur, Carrera, Luz Stamm, Lee Ann Tibbles, Kevin McLaughlin, Wenjie Wang, and Noureddine Berka. "95-P: Post transplant monitoring of mean fluorescence intensity (MFI) for high risk renal transplant patients." Human Immunology 70 (November 2009): S59. http://dx.doi.org/10.1016/j.humimm.2009.09.128.
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Luiz Costa e Silva, André, Livia Medeiros Soares Celani, Italo Medeiros Azevedo, and Aldo Cunha Medeiros. "Levamisole in treatment of urethane-induced pulmonary carcinoma in rats." JOURNAL OF SURGICAL AND CLINICAL RESEARCH 10, no. 2 (October 10, 2019): 54–64. http://dx.doi.org/10.20398/jscr.v10i2.18782.
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Objective: The potential antitumor effects of the levamisole immunomodulatory agent remain uncertain, and its beneficial effects with increased survival in the adjuvant treatment of malignant tumors are controversial. The present study aims to compare the effects of levamisole with cisplatin in the treatment of urethane-induced lung carcinoma in rats. Methods: Wistar rats were allocated into three groups (n = six each). Group A: mice with lung tumor + treatment with levamisole. Group B: mice with lung tumor + cisplatin treatment. Group C: mice with lung tumor + saline treatment. After 12 weeks of the tumor induction process, the results were validated by ex vivo fluorescence imaging, determining the mean fluorescent intensity in the animal’s lungs. Serum dosages of cytokines and alkaline phosphatase were performed. Results: Mean fluorescence intensity (MFI) in the lungs (ex vivo) was measured in all animals subjected to urethane effects. In levamisole-treated, the intensity (245 +/- 15) was lower than in cisplatin-treated (277 +/- 28), but the difference was not statistically significant (p<0.05). In those treated with saline, the MFI was 680 +/- 57, significantly higher than in the other groups (p<0.05). Dosages of TNF-α (pg/ml), IL-Iβ (pg/ml), IL-6 (pg/ml) and alkaline phosphatase (mg/dl) were significantly lower in levamisole-treated rats than in rats with cisplatin and saline (p<0.005). Conclusion: In conclusion, this study demonstrates the positive influence of levamisole in treatment of urethane-induced lung tumors in rats.
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Wheeler, Emily, Trish Berger, and Esmail Behboodi. "Bovine oocyte plasma membrane binding sites for sperm plasma membrane during in vitro oocyte maturation and fertilisation." Zygote 4, no. 1 (February 1996): 67–72. http://dx.doi.org/10.1017/s0967199400002902.
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SummaryThe experimental objective was to determine whether the capability of bovine oocyte plasma membrane to bind sperm changes during in vitro oocyte maturation and fertilisation. Binding was quantified by the intensity of tetramethylrhodamine isothiocyanate (TRITC) fluorescence at the periphery of oocytes following incubation with biotinylated sperm plasma membrane proteins and subsequent incubation with TRITC-avidin. Bovine oocytes were matured in vitro. Sample groups were removed after 0,6 and 22 h, or inseminated and further cultured for 24 or 48 h. Oocytes were denuded of cumulus cells and zona pellucida and co-incubated with 56 μg biotinylated bovine sperm plasma membrane protein for 45 min in 150 μl drops of saline-BSA. Controls were incubated for the same time period in the absence of sperm plasma membrane proteins. All oocytes were rinsed, incubated with TRITC-avidin and subsequently fixed and transferred to mounting medium. Oocytes were scanned with a confocal microscope and analysed using ImageQuant software. The binding of sperm plasma membrane was quantified by integrated fluorescent intensity in standardised ellipses spaced around the plasma membrane of the oocyte. Values are expressed as mean intensity units per 320 pixel ellipse. Binding of sperm plasma membrane continued to increase throughout in vitro oocyte maturation and fertilisation (9051, 24318 and 49953 for 0 and 22 h in vitro matured oocytes and fertilised oocytes, respectively; p = 0.0001). A dramatic decrease in sperm plasma membrane binding to the oocyte plasma membrane was observed in 2-cell embryos (mean intensity = 24477, p = 0.0001). The observed binding was primarily due to the binding of sperm plasma membrane proteins, as control oocytes incubated with TRITC- avidin only were barely visible (integrated fluorescence intensity values ranged from 8 to 3757).
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Guibert, Philippe, William Perrard, and Ce´line Morin. "Concentration Measurements in a Pressurized and Heated Gas Mixture Flow Using Laser Induced Fluorescence." Journal of Fluids Engineering 124, no. 2 (May 28, 2002): 512–22. http://dx.doi.org/10.1115/1.1456462.
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The fuel concentration in a pressurized and heated gas mixture flow was measured by LIF (laser induced fluorescence) technique. Diacetyl was used as the fluorescence tracer of fuel and was excited at a wavelength of 355 nm. Influent parameters on the LIF intensity among the equivalence ratio, the environment temperature and pressure, the flow velocity were determined from a parametric study. The technique of plans of experiments with statistical tests and analysis was investigated to determine exactly the preponderant parameters and their influence on the LIF intensity. For the experimental conditions explored in this work, the value of the LIF intensity was calculated by developing a quadratic model. By inversion of the transfer function, the equivalence ratio was deduced with a low mean relative error.
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Benammar Elgaaied, Amel, Donato Cascio, Salvatore Bruno, Maria Cristina Ciaccio, Marco Cipolla, Alessandro Fauci, Rossella Morgante, et al. "Computer-Assisted Classification Patterns in Autoimmune Diagnostics: The AIDA Project." BioMed Research International 2016 (2016): 1–9. http://dx.doi.org/10.1155/2016/2073076.
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Antinuclear antibodies (ANAs) are significant biomarkers in the diagnosis of autoimmune diseases in humans, done by mean of Indirect ImmunoFluorescence (IIF) method, and performed by analyzing patterns and fluorescence intensity. This paper introduces the AIDA Project (autoimmunity: diagnosis assisted by computer) developed in the framework of an Italy-Tunisia cross-border cooperation and its preliminary results. A database of interpreted IIF images is being collected through the exchange of images and double reporting and a Gold Standard database, containing around 1000 double reported images, has been settled. The Gold Standard database is used for optimization of a CAD (Computer Aided Detection) solution and for the assessment of its added value, in order to be applied along with an Immunologist as a second Reader in detection of autoantibodies. This CAD system is able to identify on IIF images the fluorescence intensity and the fluorescence pattern. Preliminary results show that CAD, used as second Reader, appeared to perform better than Junior Immunologists and hence may significantly improve their efficacy; compared with two Junior Immunologists, the CAD system showed higher Intensity Accuracy (85,5% versus 66,0% and 66,0%), higher Patterns Accuracy (79,3% versus 48,0% and 66,2%), and higher Mean Class Accuracy (79,4% versus 56,7% and 64.2%).
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Stosik, M., W. Deptula, K. Wiktorowicz, M. Trávníček, and K. Baldy-Chudzik. "Respiratory burst in neutrophilic granulocytes of carps (Cyprinus carpio): cytometric studies." Veterinární Medicína 47, No. 1 (March 30, 2012): 17–20. http://dx.doi.org/10.17221/5797-vetmed.
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Present studies aimed at flow cytometric analysis of respiratory burst in neutrophilic granulocytes in carps, at various stages of their ontogeny. Cytometric evaluation of the repiratory burst in PMN cells of carps demonstrated augmented values of the mean fluorescence channel of PMA-stimulated PMN cells, as compared to the value of the fluorescence channel noted for PMN cells which were not activated or did not respond to activation in response to the applied stimulator. Intensity of the fluorescence, compared to the mean fluorescence channel of the cells which were not stimulated by PMA, was most pronounced in 11- to 21-month old carps, average in the youngest carps aging 3 to 9 months, and the lowest in the eldest, 23- to 29-month old carps. In cases of analysis of the mean fluorescence channel in the selected fraction of PMA-stimulated PMN cells, as compared to the mean fluorescence channel of granulocytes which did not respond by the stimulation reaction, the most intense fluorescence was noted to develop in the eldest, i.e. 23- to 29-month old fish. In the remaining carps, on the other hand, the difference in the mean fluorescence channel was significantly lower. In parallel, the highest fraction of PMA-stimulated granulocytes was found in 11- to 21-month old carps, a lower fraction in the youngest carps aging 3 to 9 months and the lowest fraction of such granulocytes in the eldest carps, 23 to 29 months of age.
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Kaneku, H., J. G. O’Leary, B. M. Susskind, L. W. Jennings, G. B. Klintmalm, and P. I. Terasaki. "High Mean Fluorescence Intensity DSA and IgG3 Subclass DSA after Liver Transplantation Decrease Patient and Graft Survival." Transplantation Journal 94, no. 10S (November 2012): 324. http://dx.doi.org/10.1097/00007890-201211271-00602.
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Domen, Ronald E., Heather Casey, and Justine Gaspari. "56-P: Correlation of HLA donor specific antibody (DSA) titers with the luminex mean fluorescence intensity (MFI)." Human Immunology 69 (October 2008): S35. http://dx.doi.org/10.1016/j.humimm.2008.08.075.
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Oh, E., H. S. Kim, and M. Yang. "Correlation of HLA antibody mean fluorescence intensity with C1q binding status in EDTA treated real clinical samples." Clinica Chimica Acta 493 (June 2019): S63. http://dx.doi.org/10.1016/j.cca.2019.03.140.
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Suzuki, Tomonari, Satoru Wada, Hidetaka Eguchi, Jun-ichi Adachi, Kazuhiko Mishima, Masao Matsutani, Ryo Nishikawa, and Masahiko Nishiyama. "Cadherin 13 overexpression as an important factor related to the absence of tumor fluorescence in 5-aminolevulinic acid–guided resection of glioma." Journal of Neurosurgery 119, no. 5 (November 2013): 1331–39. http://dx.doi.org/10.3171/2013.7.jns122340.
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Object Gliomas contain aggressive malignant cancer, and resection rate remains an important factor in treatment. Currently, fluorescence-guided resection using orally administered 5-aminolevulinic acid (5-ALA) has proved to be beneficial in improving the prognosis of patients with gliomas. 5-ALA is metabolized to protoporphyrin IX (PpIX) that accumulates selectively in the tumor and exhibits strong fluorescence upon excitation, but glioma cells do not always respond to 5-ALA, which can result in incomplete or excessive resection. Several possible mechanisms for this phenomenon have been suggested, but they remain poorly understood. To clarify the probable mechanisms underlying the variable induction of fluorescence and to improve fluorescence-guided surgery, the authors searched for key negative regulators of fluorescent signal induced by 5-ALA. Methods A comprehensive gene expression analysis was performed using microarrays in 11 pairs of tumor specimens, fluorescence-positive and fluorescence-negative tumors, and screened genes overexpressed specifically in fluorescence-negative tumors as the possible candidates for key negative regulators of 5-ALA–induced fluorescence. The most possible candidate was selected through annotation analysis in combination with a comparison of expression levels, and the relevance of expression of the selected gene to 5-ALA–induced fluorescence in tumor tissues was confirmed in the quantified expression levels. The biological significance of an identified gene in PpIX accumulation and 5-ALA–induced fluorescence was evaluated by in vitro PpIX fluorescence intensity analysis and in vitro PpIX fluorescence molecular imaging in 4 human glioblastoma cell lines (A1207, NMCG1, U251, and U373). Knockdown analyses using a specific small interfering RNA in U251 cells was also performed to determine the mechanisms of action and genes working as partners in the 5-ALA metabolic pathway. Results The authors chose 251 probes that showed remarkably high expression only in fluorescent-negative tumors (median intensity of expression signal > 1.0), and eventually the cadherin 13 gene (CDH13) was selected as the most possible determinant of 5-ALA–induced fluorescent signal in gliomas. The mean expression level of CDH13 in the fluorescence-negative gliomas was statistically higher than that in positive ones (p = 0.027), and knockdown of CDH13 expression enhanced the fluorescence image and increased the amount of PpIX 13-fold over controls (p < 0.001) in U251 glioma cells treated with 5-ALA. Comprehensive gene expression analysis of the CDH13-knockdown U251 cells demonstrated another two genes possibly involved in the PpIX biosynthesis: ATP-binding cassette transporter (ABCG2) significantly decreased in the CDH13 knockdown, while oligopeptide transporter 1 (PEPT1) increased. Conclusions The cadherin 13 gene might play a role in the PpIX accumulation pathway and act as a negative regulator of 5-ALA–induced fluorescence in glioma cells. Although further studies to clarify the mechanisms of action in the 5-ALA metabolic pathway would be indispensable, the results of this study might lead to a novel fluorescent marker able to overcome the obstacles of existing fluorescence-guided resection and improve the limited resection rate.
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Wang, Shuhang, Wenwen Wang, Junyi Chen, Bo Zhang, Li Zhao, and Xia Jiang. "Characteristics of Dissolved Organic Matter and Its Role in Lake Eutrophication at the Early Stage of Algal Blooms—A Case Study of Lake Taihu, China." Water 12, no. 8 (August 13, 2020): 2278. http://dx.doi.org/10.3390/w12082278.
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Decaying algal blooms in eutrophic lakes can introduce organic matter into the water and change nutrient concentrations in the water column. The spatial distribution and composition characteristics, sources, and contribution to eutrophication of dissolved organic matter (DOM) in the overlying water of Lake Taihu, a typical eutrophic lake in China, were analyzed by ultraviolet–visible spectra and three-dimensional fluorescence excitation–emission matrix spectra combined with the statistical decomposition technique, parallel factor analysis. The concentration of DOM was represented by dissolved organic carbon (DOC), and DOC in overlying water of Lake Taihu was 2.86–11.83 mg/L. The colored DOM (CDOM) was characterized by an absorption coefficient at 280 nm (a280) and 350 nm (a350), which were 6.63–29.87 and 1.84–10.41 m−1, respectively. These values showed an increasing trend from southeast to northwest, and the high values were concentrated in the northwest and northern lake areas. The parallel factor analysis (PARAFAC) identified two protein-like (C1: tyrosine-like and C2: tryptophan-like) and one humic-like (C3: humic acid and fulvic acid) fluorescence components for fluorescent DOM (FDOM). The most dominant components were protein-like components (C1 + C2), whose fluorescence intensity contributed 87.55% ± 3.39% to the total fluorescence intensity (Ft) of FDOM (3.38 R.U.). The mean value of the fluorescence index (FI) and index of recent autochthonous contribution (BIX) of DOM was 1.77 and 0.92, and DOC, a280 and fluorescence intensities of FDOM components were all significantly and positively correlated with chl. a, indicating that DOM, CDOM, and FDOM were all mainly derived from algal activities and metabolites. The average humification index of the DOM was 0.66, which indicated a low humification degree. The protein-like DOM was correlated with DON and DOP, and might make great contributions to the continuous occurrence of algal blooms.
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El-Sherbiny, Dina T. "Spectrofluorometric Determination of Citalopram in Pharmaceutical Preparations and Spiked Human Plasma Using Organized Media." Journal of AOAC INTERNATIONAL 89, no. 5 (September 1, 2006): 1288–95. http://dx.doi.org/10.1093/jaoac/89.5.1288.
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Abstract The native fluorescence of citalopram (CIT) was (obtained in citrate buffer of pH 6.5 with and without β-cyclodextrin (β-CD) or sodium dodecyl sulfate (SDS) as fluorescence enhancers at 305 nm using 242 nm for excitation. Micellar systems of ionic and nonionic surfactants were investigated by measuring the fluorescence intensity of the analyte-surfactant system. In slightly acidic aqueous solution of pH 6.5, CIT was better incorporated in CDs and SDS micelles. The luminescence emission from CIT was found to be greatly enhanced by SDS micelles. The fluorescence intensity enhancements in CDs medium and in SDS as ionic surfactant relative to slightly acidic aqueous solution were 125 and 250%, respectively. Organized media-enhanced spectroflourometric methods were developed for the determination of CIT, in pure form as well as in pharmaceutical preparations. The fluorescence intensity-concentration plots were rectilinear over the ranges 0.06 to 0.64, 0.04 to 0.40, and 0.02 to 0.26 μg/mL with lower detection limits of 0.02, 0.01, and 0.007 μg/mL, either in citrate buffer only or in β-CD and SDS as organized media, respectively. Furthermore, the high sensitivity attained by using SDS as organized medium allowed in vitro spectrofluorometric determination of CIT in spiked human plasma. Interference from endogenous amino acids has been overcome by using the solid-phase extraction technique; the mean recovery (n = 5) was 100.1 ± 0.8%
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Giovannacci, Ilaria, Marco Meleti, Federico Garbarino, Anna Maria Cesinaro, Ema Mataca, Giuseppe Pedrazzi, Camilla Reggiani, et al. "Correlation between Autofluorescence Intensity and Histopathological Features in Non-Melanoma Skin Cancer: An Ex Vivo Study." Cancers 13, no. 16 (August 6, 2021): 3974. http://dx.doi.org/10.3390/cancers13163974.
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Non-melanoma skin cancer (NMSC) is the most common malignant tumor affecting fair-skinned people. Increasing incidence rates of NMSC have been reported worldwide, which is an important challenge in terms of public health management. Surgical excision with pre-operatively identified margins is one of the most common and effective treatment strategies. Incomplete tumor removal is associated with a very high risk of recurrence and re-excision. Biological tissues can absorb and re-emit specific light wave-lengths, detectable through spectrophotometric devices. Such a phenomenon is known as autofluorescence (AF). AF spectroscopy has been widely explored for non-invasive, early detection of NMSC as well as for evaluation of surgical margins before excision. Fluorescence-aided diagnosis is based on differences in spectral characteristics between healthy and neoplastic skin. Understanding the biological basis of such differences and correlating AF intensity to histological features could improve the diagnostic accuracy of skin fluorescence spectroscopy. The primary objective of the present pre-clinical ex vivo study is to investigate the correlation between the intensity of cutaneous AF and the histopathological features of NMSC. Ninety-eight lesions suggestive for NMSCs were radically excised from 75 patients (46 M; 29 F; mean age: 79 years). After removal, 115 specific reference points on lesions (“cases”; 59 on BBC, 53 on SCC and 3 on other lesions) and on peri-lesional healthy skin (controls; 115 healthy skin) were identified and marked through suture stitches. Such reference points were irradiated at 400–430 nm wavelength, and resulting emission AF spectra were acquired through spectrophotometry. For each case, AFIR (autofluorescence intensity ratio) was measured as the ratio between the number of photons emitted at a wavelength ranging between 450 and 700 nm (peak: 500 nm) in the healthy skin and that was captured in the pathological tissue. At the histological level, hyperkeratosis, neoangiogenesis, cellular atypia, epithelial thickening, fibrosis and elastosis were quantified by light microscopy and were assessed through a previously validated grading system. Statistical correlation between histologic variables and AFIR was calculated through linear regression. Spectrometric evaluation was performed on 230 (115 cases + 115 controls) reference points. The mean AFIR for BCC group was 4.5, while the mean AFIR for SCC group was 4.4 and the fluorescence peaks at 500 nm were approximately 4 times lower (hypo-fluorescent) in BCCs and in SCCs than in healthy skin. Histological variables significantly associated with alteration of AFIR were fibrosis and elastosis (p < 0.05), neoangiogenesis, hyperkeratosis and epithelial thickening. Cellular atypia was not significantly associated with alteration of AFIR. The intensity of fluorescence emission in neoplastic tissues was approximately 4 times lower than that in healthy tissues. Histopathological features such as hyperkeratosis, neoangiogenesis, fibrosis and elastosis are statistically associated with the decrease in AFIR. We hypothesize that such tissue alterations are among the possible biophysical and biochemical bases of difference in emission AF between neoplastic and healthy tissue. The results of the present evaluation highlighted the possible usefulness of autofluorescence as diagnostic, non-invasive and real-time tool for NMSCs.
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Markowitz, K., and K. Carey. "Assessing the Appearance and Fluorescence of Resin-Infiltrated White Spot Lesions With Caries Detection Devices." Operative Dentistry 43, no. 1 (January 1, 2018): E10—E18. http://dx.doi.org/10.2341/16-153-l.
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SUMMARY Objective: This in vitro study examined the effectiveness of caries detector devices in assessing the ability of resin infiltration (RI) (Icon, DMG-Hamburg, Hamburg, Germany) to improve the optical properties of enamel white spot lesions (WSLs). Methods and Materials: Ten caries-free third molars were used. Photographs, a subjective visual assessment of the photographs, fluorescent camera (FC) images using the Spectra (Air Techniques, Melville, NY, USA), and laser fluorescent (LF) readings using the DIAGNOdent (KaVo, Biberach, Germany) were obtained from each tooth's buccal surface. Specimens were coated with nail polish leaving a rectangular window on the buccal surface and placed in pH 4.5 lactic acid gel for two weeks to create a WSL. The WSLs were analyzed by the same methods. RI was applied to half of each WSL; final photographs were then taken, and caries detector assessments were conducted. FC images were converted to grayscale, and the fluorescent image's brightness intensity was measured using ImageJ. Data were analyzed with analysis of variance and Tukey-Kramer honestly significant difference test. Significance was set at α=0.05. Results: Subjective assessment of the photographs showed that RI improved the appearance of the WSLs so that they resembled intact enamel. Mean FC-brightness intensities for intact, demineralized, and demineralized RI-treated areas were 159.6 ± 9.2, 123.4 ± 7.2, and 160.9 ± 11.5, respectively. There were no significant differences in fluorescent intensity between the intact and RI areas (p=0.58). The demineralized areas had significantly lower fluorescent intensity than both the RI-treated and intact areas (p<0.001). LF values did not differ significantly between intact, demineralized, or RI-treated areas. Conclusions: This study demonstrates the ability of RI to restore artificial WSLs to the esthetics and fluorescence of intact enamel. The FC can be used to assess the optical properties of WSLs and the impact of RI on these properties.
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Yates, Ronald L., and John A. Wenninger. "Fluorometric Determination of Benzylideneacetone in Fragrance Products by Liquid Chromatography with Post-Column Derivatization." Journal of AOAC INTERNATIONAL 71, no. 5 (September 1, 1988): 965–67. http://dx.doi.org/10.1093/jaoac/71.5.965.
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Abstract A method is described for the liquid chromatographic (LC)-fluorometric determination of benzylideneacetone in fragrance products. Benzylideneacetone is first separated from other fragrance ingredients by LC and then reacted post-column with a methanolic solution of isonicotinic acid hydrazide and aluminum nitrate. The reactants are maintained at 65°C for about 1.5 min to quantitatively form the fluorescent isonicotinoyl hydrazone derivative of benzylideneacetone. The aluminum ion forms a complex with the hydrazone to enhance the fluorescence of the derivative. The amount of benzylideneacetone is determined by measuring the intensity of the fluorescence emitted by the hydrazone derivative and comparing that value with those obtained for derivatized standards. Recovery studies were conducted by spiking commercial fragrances with benzylideneacetone at concentrations of 0.01,0.05, and 0.1% (w/v). Recoveries ranged from 98 to 104% with a mean recovery of 100.2% and a standard deviation of 2.4%.
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Schimmel, Carmel, David Frazer, and Robb W. Glenny. "Extending fluorescent microsphere methods for regional organ blood flow to 13 simultaneous colors." American Journal of Physiology-Heart and Circulatory Physiology 280, no. 6 (June 1, 2001): H2496—H2506. http://dx.doi.org/10.1152/ajpheart.2001.280.6.h2496.
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Seven fluorescent microsphere colors can be used in a single experiment to estimate regional blood flow without correcting for spillover of emitted fluorescence. To extend the method to 13 colors, we compared the accuracy of three methods for spillover correction. Fixed wavelength intensities were corrected by matrix inversion, and synchronous scan spectra were corrected by least squares fit of an overdetermined system of linear equations and by least squares fit of a sum of Gaussian and Lorentzian functions. Correction methods were validated in pigs and sheep by simultaneous injections of radioactive microspheres and fluorescent microspheres of 7, 10, and 13 different colors. We induced extreme changes in flow to create regions with low fluorescent signals bound on either side by high fluorescent signals. Blood flow was determined by radioactivity and by fluorescence using both fixed excitation and emission wavelength pairs and synchronous scanning and then corrected for spillover. Correlation between fluorescent intensity and radioactivity were excellent for all three correction methods [ R 2 = 0.98 ± 0.02 (mean ± SD)]. Low-flow regions requiring large spillover correction had systematic errors for some color combinations in all methods. We conclude that for 13 fluorescent colors spillover error can be minimized so that all three correction methods provide accurate estimates of regional blood flow.
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Chuksina, J. J., E. V. Kataeva, and T. A. Mitina. "Features of immunophenotypic finding B-cell lymphoproliferative diseases by flow cytometry." Kazan medical journal 101, no. 1 (February 11, 2020): 145–52. http://dx.doi.org/10.17816/kmj2020-145.
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Aim. To assess the information content of conventional and additional immunophenotypic markers (CD200, CD305) in the differential diagnosis B-cell lymphoproliferative diseases by flow cytometry.
Methods. An immunophenotypic study using 4-color flow cytometry was performed in 204 patients with different variants of B-cell non-Hodgkin's lymphomas. The study material included peripheral blood and bone marrow. The expression of CD45, CD19, CD20, CD22, CD79b, CD79a, CD5, CD10, CD23, FMC7, CD43, CD38, CD11c, CD103, CD25, CD 200, CD 305, light chains of immunoglobulins (kappa/lambda) using monoclonal antibodies (Becton Dickinson, USA) was evaluated. The intensity of antigen expression was assessed using mean fluorescence intensity (y. e.).
Results. Conventional FMC7-positive expression revealed only half patients with different variants of leukemization of non-Hodgkin's lymphomas, whereas atypical positive expression of CD23 was observed in patients with marginal spleen lymphoma and follicular lymphoma in 27.3 and 28.6% of cases, respectively. In mantle cell lymphoma, expression of CD200 in B-cell was detected in a significantly smaller number of observations, accompanied by a significant decrease in the average intensity of CD200 fluorescence compared to B-cell chronic lymphocytic leukemia (B-CLL) cells. The mean fluorescence intensity (MFI) of CD305 in hairy cell leukemia is significantly higher than in splenic marginal zone lymphoma (SMZL) with villous lymphocytes.
Conclusion. Different levels of the information content of some conventional markers were revealed in differential immunophenotypic diagnosis of B-cell lymphoproliferative diseases by flow cytometry; the use of additional markers CD200 and CD305 was highly informative in differential diagnostics between different variants of B-cell lymphoproliferative diseases with similar immunophenotypic and morphological characteristics of lymphoid elements.
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Wells, Denise A., and Michael R. Loken. "Erratum to “Flow cytometric mean fluorescence intensity: The biophysics behind the number” [Leukemia Res. 32 (2008) 845–846]." Leukemia Research 32, no. 11 (November 2008): 1792. http://dx.doi.org/10.1016/j.leukres.2008.06.021.
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Gloudemans, A. J., E. Kuulkers, R. Campana, A. Escalante, M. Kole, and Y. Mollard. "Re-evaluation of Lunar X-ray observations by Apollo 15 and 16." Astronomy & Astrophysics 649 (May 2021): A174. http://dx.doi.org/10.1051/0004-6361/202140321.
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The Apollo 15 and 16 missions were the first to explore the Lunar surface chemistry by investigating about 10% of the Lunar surface using a remote sensing X-ray fluorescence spectrometer experiment. The data obtained have been extensively used to study Lunar formation history and geological evolution. In this work, a re-evaluation of the Apollo 15 and 16 X-ray fluorescence experiment is conducted with the aim of obtaining up-to-date empirical values for aluminum (Al) and magnesium (Mg) concentrations relative to silicon (Si) of the upper Lunar surface. An updated instrument response, a newly reconstructed Lunar trajectory orbit, and improved intensity ratio calculations were used to obtain new intensity ratio maps. The resulting Lunar Al/Si and Mg/Al X-ray maps show a clear distinction in Lunar mare and highland regions. The mean Al/Si and Mg/Al intensity ratios for the mare regions obtained from the newly obtained maps are 0.54 ± 0.07 and 0.54 ± 0.17, respectively; for the highland regions, the values are 0.76 ± 0.07 and 1.07 ± 0.13, respectively. For the Mg/Si intensity ratio, no clear distinction between Lunar features is obtained and we derived a mean value of 0.47 ± 0.13. Our determined intensity ratios are lower than previously published. These values can be used to infer concentration ratios when accounting for Solar activity, inter-orbit variability, and measurements from different instruments. We employed a correction to infer concentration ratios by comparing our intensity ratios directly to Lunar rock concentrations obtained from various Lunar missions.
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Zhao, Jin Hui, Hai Bin Xiao, Hai Chao Yuan, Qian Hong, and Mu Hua Liu. "Application of Three-Dimensional Fluorescence Spectroscopy Coupled with ATLD in Rapid Determination of Triazophos Content in Duck Meat." Applied Mechanics and Materials 651-653 (September 2014): 362–66. http://dx.doi.org/10.4028/www.scientific.net/amm.651-653.362.
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The triazophos is a kind of organic phosphorus pesticide, the quantitative determination model based on three-dimensional fluorescence spectroscopy coupled with alternating trilinear decomposition (ATLD) was explored for realizing the rapid determination of triazophos content in duck meat. Firstly, three-dimensional fluorescence spectra of duck meat extract, triazophos standard solution and duck meat extract containing triazophos were explored, respectively. Secondly, the fluorescence quenching phenomenon of the triazophos in duck meat extract was analyzed. Lastly, the number of components for three linear decomposition of ATLD was set as 2 by using the core consistency diagnostic, and the calibration curve between the relative fluorescence intensity and the actual concentration of the triazophos was established by using ATLD. The experimental results showed that the determination coefficient (R2) and the root mean squared error of prediction (RMSEP) for the proposed model in this paper were 0.9741 and 0.764 respectively, and it was feasible to predict the triazophos content in duck meat combining with three-demensional fluorescence spectroscopy and ATLD.
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Murase, N., M. Y. Gao, N. Gaponik, T. Yazawa, and J. Feldmann. "SYNTHESIS AND OPTICAL PROPERTIES OF WATER SOLUBLE ZnSe NANOCRYSTALS." International Journal of Modern Physics B 15, no. 28n30 (December 10, 2001): 3881–84. http://dx.doi.org/10.1142/s0217979201008901.
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ZnSe nanocrystals are prepared in water by a wet chemistry method. By selecting an appropriate pH value and surface-capping agents, a whitish blue fluorescence peaking at 470 nm is observed under ZV irradiation. The intensity of this fluorescence increases dramatically under reflux and saturates after ~ 40 hrs. The final mean size of the ZnSe nanocrystals measured by transmission electron microscopy is aboyt 2 nm in diameter. The quantum efficiency of the fluorescence form the final solution is estimated to be ~1%, although the preparation conditions have not yet been completely optimized. These properties are discussed in comparison with those of similarly prepared CdTe and differently prepared ZnSe nanocrystals.
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McLennan, H. J., M. L. Sutton-McDowall, S. Heng, and J. G. Thompson. "153 Fertilisation of Cattle Oocytes is Linked to Novel Waves of a Ca2+ Fluorophore in Cumulus Cells." Reproduction, Fertility and Development 30, no. 1 (2018): 216. http://dx.doi.org/10.1071/rdv30n1ab153.
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During fertilization, multiple intracellular calcium (Ca2+) oscillations are initiated after sperm binding to the oocyte vitelline membrane. This Ca2+ signalling has been extensively studied in denuded mouse and Xenopus oocytes but minimally studied in larger mammals. Cows in particular are unusual, as the few studies on oocyte activation have observed fewer Ca2+ oscillations during fertilisation compared with mice. Furthermore, cattle intracytoplasmic sperm injection (ICSI) is inefficient, despite parthenogenetic activation occurring readily. We hypothesise that cumulus cells are important for cattle oocyte activation at fertilisation. Here, we assessed the behaviour of Ca2+oscillations in fertilising intact cattle cumulus–oocyte complexes (COC). Abattoir-derived cattle COC were matured and fertilised in vitro using Bovine Vitro Media Suite (IVF Vet Solutions). The COC were stained 3.5 h after insemination with the Ca2+ fluorescent probe Fluo4AM (5 μM, Molecular Probes Inc., Eugene, OR, USA) for 30 min, washed, and imaged every 5 min for 6 h in a Fluoview FV10i incubating time-lapse confocal microscope (Olympus) before being returned to culture. Embryo development was assessed at Day 8 to confirm fertilisation. Fluo4AM fluorescence intensity was assessed using FIJI ImageJ. Mean relative intensity over time was graphed for specific regions of interest and the area under graphs was calculated to quantify differences for comparison using a Mann-Whitney Test (mean ± SEM). Experiment 1 (4 reps of 10 COC) compared confirmed fertilised v. uninseminated; experiment 2 (2 reps of 10 COC) compared inseminated COC ± 10 μM BAPTA-AM (Ca2+ chelator, Sigma-Aldrich, St. Louis, MO, USA). There were distinct coordinated waves of differing Fluo4AM intensity in both the oocyte and the cumulus cells surrounding the confirmed fertilised oocytes. This contrasted to the random uncoordinated flashes of Fluo4AM fluorescence in the cumulus cells of the uninseminated oocytes. The fluorescence pattern in +BAPTA-AM COC matched the random flashes observed in the uninseminated group of experiment 1. The fluorescence in the media surrounding the COC immediately following the Fluo4AM waves spiked and then plateaued at a higher level of fluorescence. This was quantified by assessing the area under the graph for 1 h of the plateau following the fluorescence spike. There were no differences between confirmed fertilised (346.4 ± 41.62) and uninseminated groups (239.8 ± 32.08; P > 0.05), but this was affected by differences in cumulus dispersal due to the presence or absence of sperm. Experiment 2 used BAPTA-AM to block oocyte activation with sperm present in both groups and showed a significant difference between the fluorescence increase in the media of the 2 groups (–BAPTA-AM: 311.2 ± 31.57, +BAPTA-AM: 201.4 ± 26.59; P < 0.03). Although the physiological significance has yet to be determined, we have observed a novel Ca2+ wave in the cumulus cells that could be linked to oocyte activation in cattle. There was a significant increase in Fluo4AM fluorescence in the media surrounding the COC, which may indicate cumulus cells are releasing Ca2+ at the time of oocyte activation.
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Dendrou, Calliope A., Erik Fung, Laura Esposito, John A. Todd, Linda S. Wicker, and Vincent Plagnol. "Fluorescence Intensity Normalisation: Correcting for Time Effects in Large-Scale Flow Cytometric Analysis." Advances in Bioinformatics 2009 (November 17, 2009): 1–6. http://dx.doi.org/10.1155/2009/476106.
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A next step to interpret the findings generated by genome-wide association studies is to associate molecular quantitative traits with disease-associated alleles. To this end, researchers are linking disease risk alleles with gene expression quantitative trait loci (eQTL). However, gene expression at the mRNA level is only an intermediate trait and flow cytometry analysis can provide more downstream and biologically valuable protein level information in multiple cell subsets simultaneously using freshly obtained samples. Because the throughput of flow cytometry is currently limited, experiments may need to span over several weeks or months to obtain a sufficient sample size to demonstrate genetic association. Therefore, normalisation methods are needed to control for technical variability and compare flow cytometry data over an extended period of time. We show how the use of normalising fluorospheres improves the repeatability of a cell surface CD25-APC mean fluorescence intensity phenotype on CD4+ memory T cells. We investigate two types of normalising beads: broad spectrum and spectrum matched. Lastly, we propose two alternative normalisation procedures that are usable in the absence of normalising beads.
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Gebhard, D. F., A. Mittelman, C. Cirrincione, H. T. Thaler, and B. Koziner. "Comparative analysis of surface membrane immunoglobulin determination by flow cytometry and fluorescence microscopy." Journal of Histochemistry & Cytochemistry 34, no. 4 (April 1986): 475–81. http://dx.doi.org/10.1177/34.4.3081624.
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The analysis of membrane surface immunoglobulin (SmIg) on B lymphocytes was carried out in 59 normal individuals and nine patients with B-cell non-Hodgkin's lymphomas by conventional immunofluorescence microscopy and flow cytometry. Five channel settings of a cytofluorograph were evaluated (100, 150, 200, 250, 300) and the mean and standard deviation of the percent positive cells were calculated and compared to the mean and standard deviation of the microscope reading. On the basis of the relative fluorescence reactivity, we were able to determine a fluorescence intensity at which the results of flow cytometry and fluorescence microscopy were comparable. In normal individuals, for cells expressing surface Ia, the channel giving similar results to that of fluorescence microscopy was 150; for kappa and lambda chains, channel 200; for Fab'PV, channel 200; and for IgM, channel 250. In patients with B-cell non-Hodgkin's lymphomas, for cells expressing surface Ia the channel giving similar results to that of fluorescence microscopy was 100; for kappa, channel 100; for lambda, channel 200; for Fab'FV, channel 150; and for IgM, channel 150. Flow cytometric analysis of SmIg appears to be superior to fluorescence microscopy in efficiency, and has the added advantages of being a rapid, sensitive, and objectively quantitative methodology.
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Narumi, Shunji, Yoshihiko Watarai, Norihiko Goto, Takahisa Hiramitsu, Makoto Tsujita, Manabu Okada, Kenta Futamura, et al. "Everolimus-based Immunosuppression Possibly Suppresses Mean Fluorescence Intensity Values of De Novo Donor-specific Antibodies After Primary Kidney Transplantation." Transplantation Proceedings 51, no. 5 (June 2019): 1378–81. http://dx.doi.org/10.1016/j.transproceed.2019.03.019.
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Liu, Lin-I., Nikolay N. Barashkov, Tamara S. Novikova, Chintamani P. Palsule, Shubhra Gangopadhyay, and Walter L. Borst. "Fluorescence Studies on New Epoxypolymer—Dye Compositions for Ultrafast Wavelength Shifters." Applied Spectroscopy 50, no. 12 (December 1996): 1545–52. http://dx.doi.org/10.1366/0003702963904467.
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Fast wavelength shifters with fluorescence decay times in the low nanosecond range were prepared from mixtures of various dyes in epoxypolymer compositions on the base of diglycidyl ether of bisphenol-A (DGEBA) with hexahydrophthalic anhydride (HHPA) or trimethoxyboroxine (TMBOX). Three possible sample preparation methods yielding high transmittance and high-fluorescence intensity were compared. The characteristics of the new wavelength shifters were determined with continuous-wave (cw) excitation of the fluorescence and by pulsed-laser excitation, the latter coupled with an analysis of the fluorescence decay times. The cw emission and time-resolved fluorescence spectra of these new wavelength shifters were studied as a function of component concentration in order to optimize the decay times, the emission peaks, and the quantum efficiencies for potential use in high-energy particle detectors. The mean decay times of most of the epoxypolymer–dye mixtures were found to be 2.6–3.1 ns, which is significantly shorter than the wavelength shifters currently in use. We also used fluorescence techniques to study the cure kinetics and fluorescence yields in epoxypolymer–diglycidyl ether of 3′,3″-dihydroxy-2,5-diphenyloxadiazole (DGEPOD) compositions.
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Abedi, Mehrdad, Deborah A. Greer, Bethany A. Foster, Delia A. Demers, Gerald A. Colvin, Mark S. Dooner, and Peter J. Quesenberry. "Marrow Derived Muscle Colonies Are a Clonal Phenomenon." Blood 104, no. 11 (November 16, 2004): 2692. http://dx.doi.org/10.1182/blood.v104.11.2692.2692.
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Abstract We have previously established a model of plasticity of marrow to skeletal muscle that is based on transplantation of GFP positive marrow and cardiotoxin injury to the tibialis muscle. In these experiments, we have observed colonies of GFP positive muscle fibers, defined as 3 or more myocytes. We noted that individual GFP positive fibers showed marked heterogeneity of fluorescence. In sharp contrast, colonies of GFP+ cells, showed homogeneous fluorescence. This was confirmed by using confocal microscopy and by measuring the mean fluorescent intensity of the individual cells in the colonies. When the intensity of the green fluorescence in individual fibers was graded to dull, moderate or bright, in 95% of the colonies counted, showed homogenous intensity of green fluorescence while for single GFP fibers dispersed throughout the specimen the probability of 3 cells being the same color was only 14.12%. Therefore the probability of 95% of colonies to have a minimum of 3 homogenous fibers by random association is less than 0.0001. To show that colonies are not from clumps of cells injected into the muscle, we compared the number of the colonies in two different experimental setting where in both GFP positive marrow cells were injected intravenously after 900cGy of radiation followed by cardiotoxin injury to the muscle. Animals who received two cycle of G-CSF mobilization were compared with those who had lineage negative marrow cells directly injected into their muscle, one day after injury. The incidence of muscle colonies remained the same between the groups. The incidence increased in experiments with multiple cycles of mobilization and injury and also in mdx mouse that has spontaneous ongoing regeneration of its muscles. Cotransplantation of marrow cells from yellow fluorescent protein (YFP) and cyan fluorescent protein (CFP) transgenics into C57BL/6 mice followed by cardiotoxin injury showed colonies that were either from YFP or CFP cells. No mixed colonies were found. Transplantation of YFP marrow cells before injury followed by CFP cells after injury and vice versa showed colonies only from cells that were infused at the time of transplantation. Colonies were seen only in samples that received CD45, C-Kit and/or Sca positive marrow cells and not in those negative populations. These cells resulted in a GFP+ CD45 negative population 4 weeks after transplantation and produced Myf5+ and MyoD+ myoblasts three days after injury. These data suggests that marrow derived muscle colonies are a clonal phenomenon similar to CFU-S cells in recipient spleens after transplantation.
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Chen, Sisi, Jianing Wang, Lei Zhang, and Hao Xia. "Experimental study on alleviating atherosclerosis through intervention of mitochondrial calcium transport and calcium-induced membrane permeability transition." Journal of Investigative Medicine 69, no. 6 (April 27, 2021): 1156–60. http://dx.doi.org/10.1136/jim-2020-001765.
Full textAbstract:
To investigate the effort of mitochondrial calcium transport and calcium-induced membrane permeability transition in alleviating atherosclerosis. The experimental mice were divided into three groups: the control group (C57BL/6 mice with normal diet), the atherosclerosis group (apolipoprotein E-deficient (ApoE−/−) mice with high-fat diet) and the mitochondrial targeting agent group (ApoE−/− mouse with high-fat diet). The mean fluorescence intensity of Ca2+ in the atherosclerosis group is significantly higher than control group and mitochondrial targeting agent group. But the mean fluorescence intensity of Ca2+-ATPase is lower than other groups. The macrophage recruitment (F4/80 positive area) and the expression of tumor necrosis factor alpha, interleukin-6, pyrin domain containing protein 3, intercellular cell adhesion molecule-1, p38 mitogen-activated protein kinase and Jun kinase 1/2 phosphorylation in the atherosclerosis group are higher that other groups. Treatment with mitochondrial targeting agents reduced the levels of elevated cyt C and cleaved caspase-3 in atherosclerotic mice (p<0.05). Mitochondrial targeting agents interfere with mitochondrial calcium transport and calcium-induced membrane permeability transition, inhibit MAPK/JNK pathway activation, inhibit foam cell formation and alleviate the process of atherosclerosis.
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Borowitz, Michael J., Jonathan Shuster, Andrew J. Carroll, Michael Nash, A. Thomas Look, Bruce Camitta, Donald Mahoney, Stephen J. Lauer, and D. Jeanette Pullen. "Prognostic Significance of Fluorescence Intensity of Surface Marker Expression in Childhood B-Precursor Acute Lymphoblastic Leukemia. A Pediatric Oncology Group Study." Blood 89, no. 11 (June 1, 1997): 3960–66. http://dx.doi.org/10.1182/blood.v89.11.3960.
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Abstract This report describes the prognostic significance of the intensity of surface membrane antigen expression in a series of 1,231 children older than 1 year with newly diagnosed B-precursor acute lymphoblastic leukemia (ALL) treated on Pediatric Oncology Group (POG) treatment protocols. All patients had dual-color flow cytometric immunophenotyping performed at a central reference laboratory with a standard panel of monoclonal antibodies. The flow cytometers used in the study were calibrated with a standard fluorescence microparticle that permitted conversion of relative fluorescence channels to standard units of mean equivalents of soluble fluorochrome (MESF). In univariate analysis, fluorescence intensity of CD45 and CD20 was significantly associated with event-free survival (EFS), whereas other markers showed no significant correlation with outcome. Patients whose blasts were greater than the 75th percentile of intensity for CD45 (corresponding to 18,000 MESF units with CD45-FITC, or about 8% of the intensity of normal lymphocytes) fared significantly worse than those with lower-density CD45, and those whose blasts were greater than the 25th percentile of intensity for CD20 (corresponding to 17,900 MESF units with CD20-PE) had a poorer EFS. The intensity of both CD45 and CD20 was independently correlated with outcome. There was no significant correlation between intensity of expression of either antigen and traditional clinical risk factors, ploidy, or t(9; 22) or t(1; 19). All patients with t(4; 11) had CD45 intensity greater than the 75th percentile, but CD45 intensity retained its prognostic significance after adjusting for t(4; 11). In multivariate analysis, both CD45 intensity greater than the 75th percentile and CD20 intensity greater than the 25th percentile were significantly correlated with poor outcome independently of previously reported poor prognostic factors including National Cancer Institute (NCI) risk group, ploidy, trisomies of 4 and 10, and adverse translocations including t(1; 19), t(9; 22), and t(4; 11). We conclude that in childhood B-precursor ALL, the intensity of expression of CD20 and CD45 provides prognostic information not available from simple consideration of antigen expression as positive or negative, and adds to that obtained from traditional clinical and biologic risk factors.