Concentration Of Rhodamine Research Articles

Histamine Increased the Uptake of Rhodamine 123 in Mitochondria of Living Parietal Cells in Cultured Gastric Glands from Starved Guinea Pigs

We previously found that parietal cells in guinea pigs starved for a few days contained giant mitochondria while the cells of animals starved and then injected with histamine mostly did not. To test whether mitochondria change their size and activity according to energy demands for acid secretion, we examined the dynamics of mitochondria stained by rhodamine 123 in living parietal cells in gastric glands under a confocal microscope. The glands were isolated from guinea pigs starved for 60-72 hr. Because mitochondria were closely packed in the cytoplasm, we failed to observe the morphological changes of each mitochondrion in parietal cells. However, we successfully observed that 10-5 M histamine induced an increase in the fluorescence intensity (the concentration of rhodamine 123) in mitochondria in subpopulations of parietal cells; the fluorescence intensity increased sharply within minutes after the histamine administration in some cells, while it gradually increased from just after the administration in other cells. We also found that a subpopulation of mitochondria within a parietal cell responded to the secretagogue. The findings suggest that parietal cells exist as a heterogeneous population in gastric glands and contain heterogeneous mitochondria in terms of their mitochondrial response to histamine.

2] Fluorescence-sensing methods

Novel approaches to sensor design, based on the use of an internal standard with appropriate spectral properties, provide new possibilities for designing simple devices for fluorescence sensing. Detection of combined emission from the reference and an analyte-sensitive fluorophore has been achieved in numerous measurements in cuvettes, tissues, and high-throughput formats. These methods have been used with a long-lifetime reference to measure pH, O2, pCO2, glucose, and calcium by means of modulation-sensing methods as well as by the use of oriented films as the reference for polarization sensing of glucose, pH, oxygen, and lactate. Polarization sensing has also been developed with visual detection to measure the concentration of rhodamine B and pH. Modulation and polarization sensing was found to be effective in highly scattering media such as Intralipid or tissue. The applicability of these technologies to transdermal diagnostics depends on the availability of red fluorophores that can be used in vivo. One dye that could possibly be used is indocyanine green (IcG), which absorbs and emits at wavelengths above 700 nm. Furthermore, IcG has already been approved for use in humans for monitoring burn severity and it has been detected through the skin. It appears likely that modern optics and electronic technology will allow the development of practical devices for biomedical use as shown in Scheme 1.

Global configuration of single titin molecules observed through chain-associated rhodamine dimers.

The global configuration of individual, surface-adsorbed molecules of the giant muscle protein titin, labeled with rhodamine conjugates, was followed with confocal microscopy. Fluorescence-emission intensity was reduced because of self-quenching caused by the close spacing between rhodamine dye molecules that formed dimers. In the presence of chemical denaturants, fluorescence intensity increased, reversibly, up to 5-fold in a fast reaction; the kinetics were followed at the single-molecule level. We show that dimers formed in a concentrated rhodamine solution dissociate when exposed to chemical denaturants. Furthermore, titin denaturation, followed by means of tryptophan fluorescence, is dominated by a slow reaction. Therefore, the rapid fluorescence change of the single molecules reflects the direct action of the denaturants on rhodamine dimers rather than the unfolding/refolding of the protein. Upon acidic denaturation, which we have shown not to dissociate rhodamine dimers, fluorescence intensity change was minimal, suggesting that dimers persist because the unfolded molecule has contracted into a small volume. The highly contractile nature of the acid-unfolded protein molecule derives from a significant increase in chain flexibility. We discuss the potential implications this finding could have for the passive mechanical behavior of striated muscle.

Evaporating and combusting droplet temperature measurements using two-color laser-induced fluorescence

The paper presents a new technique based on laser-induced fluorescence, allowing droplet temperature measurement of evaporating and combusting droplets to be performed. The liquid spray is seeded with a low concentration of rhodamine B. The fluorescence, induced by the green line of an argon laser, is measured on two separated color bands. It is demonstrated that two color bands can be selected for their strong difference in the temperature sensitivity of the fluorescence quantum yield. The determination of the fluorescence ratio between the fluorescence intensity corresponding to each color band allows the tracer concentration and the droplet size dependences to be eliminated. The technique was applied on a monodisperse spray: the effect of a thermal impulse on the distribution of the droplet temperature is studied and, the temperature of combusting droplets is investigated.

Absorption analysis of a single microparticle by optical force measurement

A method is proposed for precisely and instantaneously analyzing the optical absorption of a single microparticle. This method is based on the measurement of radiation pressure exerted on a particle, in which the Brownian motion of the particle is observed via total internal reflection microscopy, and then the femto-Newton-order radiation pressure induced by absorption is determined by thermodynamic analysis. On the basis of the Mie–Debye scattering theory, the imaginary part of the refractive index is estimated from the strength of the force using knowledge of the real part and the diameter of the particle. As a preliminary experiment, the concentration of rhodamine B molecules in a poly(methylmethacrylate) particle was estimated.

Characterizing mixing in a rotating drum bioreactor for solid-state fermentation

A method, based on the use of wheat bran particles dyed with Rhodamine-WT as tracer particles, was developed to characterize mixing in a 200 l rotating drum bioreactor used for solid state fermentation. The extraction process contributes a 15% relative error in determining Rhodamine concentrations. Extraction efficiency is not affected by autoclaving of the bran and there is no inter-particle transfer of dye during the mixing of bran within the drum. For an unbaffled drum rotated at 5 rpm the axial dispersion coefficient is 9.15 cm2 min−1.

Visual Drop Test of Hemoglobin in Whole Blood by Using Ring-like Concentration of Rhodamine B onto Octadecylsilanized Silica Plate

Abstract It has been found that some dye solutes become concentrated along the perimeter of an aqueous drop sitting on an octadecylsilanized silica plate. The fluorescent ring of Rhodamine B was applied to a visual test of hemoglobin in whole blood. When a drop of diluted blood and the dye is set on the plate, the resulting fluorescent ring can be observed through the drop with an ultraviolet lamp in the dark only for the samples of low hemoglobin content.

Engineering the tissue which encapsulates subcutaneous implants. III. Effective tissue response times.

The results of two previous studies have shown that implant porosity can be used to increase both the measured diffusion coefficients and the vascularity within the tissue encapsulating long-term subcutaneous implants. This study investigates the hypothesis that the analyte concentrations within the tissue surrounding porous implants will respond more quickly to changes in plasma levels than does the densely packed, avascular fibrous capsule surrounding nonporous implants. The average concentration of lissamine-rhodamine was measured in tissue within 100 microm of the following implants at four different times following injection of the tracer: PVA-skin, PVA-5, PVA-60, PVA-700 (polyvinyl alcohol nonporous, 5 microm, 60 microm, and 700 microm mean pore sizes, respectively) and PTFE-0.5 and PTFE-5 (polytetrafluoroethylene 0.5 microm and 5 microm mean pore sizes, respectively). The results were compared to those of unimplanted subcutaneous tissue (SQ). In addition, the data were analyzed with a simple two-compartment model in which a tissue response time constant (taup) was extracted. As in the case of vascular density, the cellular dimension of the PVA-60 pore sizes produced surrounding tissue with the optimum response times to changes in plasma concentrations. The concentrations of rhodamine within the tissue surrounding the PVA-60 implant were the highest at all time points and responded to the change in plasma rhodamine concentration approximately three times more quickly (taup = 764 s) than the fibrous tissue encapsulating the nonporous PVA-skin (taup = 2058 s) and more than twice as quickly as SQ (taup = 1627 s). The overall mass transfer rate between plasma and the tissue surrounding the different implants calculated from the permeability and density of vessels from the previous study correlated very well (r2 = 0.7, p < .02, slope of 0.98) with the reciprocal of the tissue response time constant (taup).

Stoichiometry of coupling of rhodamine 123 transport to ATP hydrolysis by P-glycoprotein.

In order to describe the transport mechanism of P-glycoprotein, it is essential to know the coupling ratio, i.e. the moles substrate transported/mole ATP hydrolyzed. P-glycoprotein couples ATP hydrolysis at two ATP-binding sites to transport of a wide variety of neutral or cationic lipophilic compounds. Previously published coupling ratios have fallen within the range 0.02-0.8 mol substrate transported/mol ATP hydrolyzed. We studied the energetics of transport by P-glycoprotein, performing quantitative measurements of the rates of ATP hydrolysis and transport of rhodamine 123 by P-glycoprotein, using isolated P-glycoprotein-rich plasma membrane vesicles. The continuous fluorescence-based assay of rhodamine 123 transport allowed accurate measurement of initial transport rates. Since we measured uptake of rhodamine 123 into the vesicles as a loss of fluorescence, we avoided the problem of high background due to substrate binding to the membranes. The coupling ratio of the transport reaction increased as the rhodamine 123 concentration increased, showing that the basal ATPase activity of P-glycoprotein was progressively recruited for rhodamine 123 transport. Both of the previously identified transport sites of P-glycoprotein [Shapiro, A. B. & Ling, V. (1997a) Eur J. Biochem. 250, 130-137] were involved in transport of saturating concentrations of rhodamine 123. At saturating rhodamine 123 and 0.3 mM ATP, the coupling ratio was 0.83, suggesting a mechanistic coupling ratio of 1. Interestingly, the coupling ratio decreased as the ATP concentration increased so that, at 1.5 mM, close to the cytoplasmic concentration of ATP, the coupling ratio was 0.57. The physiological significance of this effect is not yet understood.

Transport through ultrathin polyelectrolyte films

Many applications of ultrathin films require knowledge of the transport of molecules or ions through these films. In the case of films made of polyelectrolytes this may be a very interesting property since the polymer network may entrap large molecules but be penetrable to small ones. In order to obtain information on transport processes, the time dependence of the fluorescence of a dye (FITC) attached to a polymer and embedded in a defined, variable depth inside the film was studied by total internal reflection fluorescence. Adding a rhodamine solution to the outer aqueous phase, FITC quenching due to energy transfer was observed. From this the surface concentration and permeability of rhodamine was determined. We derive a depth-dependent diffusion coefficient of the order of 10 −15 cm 2 s −1. Studying the paramagnetic quenching by the spin label 2,2,6,6,-tetramethyl-4-piperidinol-1-oxide the diffusion coefficient is at least two orders of magnitude larger for this smaller molecule.

Induction of multixenobiotic resistance in mussel blood cells

Mussel blood cells can easily be removed from live animals without killing them. These cells express an MDR-like protein and have shown rhodamine B exclusion activity when single cell fluorescence measurements using computerized confocal laser microscope were performed. Treatments of mussels with up to 10 μg/ml vincristine enhanced the ability of the treated blood cells to lower their intracellular concentration of rhodamine B and increased the expression of the protein detected by the C219 monoclonal antibody. These responses are dose-dependant and stable for a period of over 14 days. The MXR phenotope could thus be valuable as a biomarker of exposure.

A Realistic Diffusion Model for Ultrathin Polyelectrolyte Films

In order to obtain information on transport processes in ultrathin films of polyelectrolytes, we studied the time dependence of the fluorescence of a dye (FITC) attached to a polymer and embedded in a defined, variable depth inside the film by total internal reflection fluorescence (TIRF) spectroscopy. Adding a rhodamine solution to the outer aqueous phase, we observe FITC quenching due to energy transfer and from this determine surface concentration and permeability of rhodamine. We derive a diffusion coefficient on the order of 10-15 cm2/s. This value can be manipulated by changing the film structure. So, the diffusion coefficient varies by nearly 2 orders of magnitude going along the surface normal. Studying the paramagnetic quenching by the smaller spin label TEMPOL, we observe that the diffusion coefficient is more than a factor of 200 larger for this molecule.

Spectrophotometric determination of mercury(II) by its adsorption on polyvinyl chloride film as ion associate with Rhodamine B.

Cationic dyes formed ion-association complexes with tribromo mercury(II) in aqueous solution. The complexes formed were adsorbed on a polyvinyl chloride sheet (soft type), and the colored species adsorbed were used for the measurement of mercury. The optimum concentrations of KBr, H2SO4 and Rhodamine B were 1×10-2 M (M=mol dm-3), 0.3 M and 1×10-4 M, respectively. The detection limit of Hg was 0.04 ppm at shaking time of 10 min. and 35°C. The proposed method is similar to ion pair solvent extraction but is simple and is more desirable than solvent extraction because it does not need any organic solvents.

A rotational system for paint finishing

The aggregation caused quench (ACQ) effect in traditional fluorescent molecules can lead to a significant fluorescent intensity decrease of fluorescent-based materials during aggregation or at solid state, which apparently limits their application. To overcome this effect, in this paper, a series of water-based fluorescent paints doped with rhodamine B were synthesized and systematically characterized using photoluminescence (PL) spectrum and other analytical methods Rhodamine B was employed because it can be adsorbed onto the shell of latex by ionic attraction force during emulsion polymerization, and hence its aggregation trends can be inhibited, thus emitting fluorescent light effectively. To explore this phenomenon, a series of characterizations were employed. Firstly, the different emulsion polymerization processes, such as cationic emulsion polymerization and anionic emulsion polymerization of the systems were studied with real-time monitoring according to PL spectrum. Secondly, the factors that affect the luminescence behavior of the fluorescent latexes were studied systematically by varying the different conditions, such as the dispersing forms of rhodamine B, the concentration of rhodamine B and the latex particles, the size, and glass transition temperature of latex particles. Lastly, the relationship between the fluorescence property of the cured fluorescent latex and the testing temperatures were also studied. The research findings herein not only reports a way to inhibit the ACQ effect of traditional fluorescent molecules, but also are predicted to be beneficial to the development of the environment-friendly smart coatings.

Effects of hypotonic and hypoionic media on drug pumping by P‐glycoprotein expressed in epithelial and nonepithelial cell lines

The effects of anisotonic and anisoionic media on the drug-pumping function of P-glycoprotein (Pgp) were studied in epithelial and nonepithelial cells. We used HT-29 colon cells (HT-29/Pgp-) induced to express Pgp and MDR phenotype (HT-29/Pgp+) and NIH3T3 (3T3/Pgp-) cells which were stably transfected with human MDR1 DNA (3T3/Pgp+). Intracellular concentrations of rhodamine 123 (R-123) preloaded into cells were monitored as a function of time by fluorescence imaging microscopy, while cells were superfused with media of different tonicity and/or ionic strength. Efflux was analyzed by a single exponential decay function. In all media tested efflux was considerably higher in Pgp+ than Pgp- cells. In both HT-29 and 3T3 cells loaded with dye in isotonic conditions, dye efflux was not significantly different whether it was measured in isoionic-isotonic (130 mM NaCl, 300 mOsm), hypoionic-isotonic (87 mM NaCl), or hypoionic-hypotonic (200, 150, or 100 mOsm) media throughout the entire experiment or whether the media were changed during the experiment. Similar results were obtained when cells were preincubated and preloaded with dye under hypotonic conditions. Under extreme hypotonic and hypoionic challenge (changing from 130 mM NaCl-300 mOsm to 43 mM NaCl-100 mOsm medium), 3T3 cells, but not HT-29 cells, underwent marked shape and size changes which reduced R-123 cell-associated fluorescence. The changes were most conspicuous in Pgp+ cells, possibly reflecting a Pgp effect on the osmotic or osmoregulatory properties of the cells. However, drug-pumping activity remained essentially unimpaired even under the most extreme hypotonic/hypoionic conditions.

Line narrowing in the dye solution with scattering centers

As was shown by Markushev et al. [1], laser-like emission without cavity can be obtained from a scattering gain medium, such as powder of Nd doped laser crystals. In the recent work by Lawandy et al. [2] a close phenomenon was observed in a concentrated rhodamine 640 dye solution in the presence of scatterers. The work in Ref. [2] is the first where gain and scattering are separate. In this case lasing evidently is not initiated within the particles, in contrast to the Markushev et al. case, where the gain is in the particles, which supports morphology-dependent resonances. The work by Sha et al. [3] showed similar results in concentrated dye, but it also showed that introduction of a low density of scatterers raises the threshold required for the laser-like effects in the low-concentrated dye. We carried out our own experiments in rhodamine 6G laser dye and observed the laser-like effects both in dilute and concentrated dye with and without scatterers. In our experiment the wavelength of stimulated emission was strongly dependent on the scatterers' concentration. Our observations and some results of Refs. [2,3] are explained with a simple ASE (amplified spontaneous emission) model.

21 レーザー誘起蛍光法による流体温度計測の不確かさ評価

An automated technique for measuring an instantaneous, two-dimensional temperature distribution in water has been developed with a digital image processing system. The thermal field is visualized by laser-induces fluorescence of Rhodamine B. The fluorescence of Rhodamine B decreases with temperature increase. A normalized calibration curve, which is not affected by laser intensity, concentration of Rhodamine B and optical configuration, can be obtained. Uncertainty intervals associated with the present technique are systematically evaluated. A steady temperature field in a rectangular enclosure is measured by the present technique. The instantaneous temperature profile measured shows good agreement with both the analytical solution and the result measured by thermocouples within the experimental uncertainty. An unsteady temperature field is also measured. The mean temperature profile is in good agreement with the result of MIYATA (1978).

Catalytic Determination of Ultratrace Amounts of Ruthenium with Oscillopolarography Monitoring

Abstract The single sweep oscillopolarographic behaviour of Rhodamine B in sulphuric acid medium was investigated. A novel, sensitive and selective catalytic method with oscillopolarography monitoring for the determination of ultratrace amounts of ruthenium was described, based on the catalytic effect of Ru(III) on the slow redox reaction occuring between Rhodamine B and potassium periodate in sulphuric acid medium at 25 °C. Single sweep oscillopolarography is used to monitor the changes in concentration of Rhodamine B by means of the second derivative wave at -0.55 V vs. SCE. The determination range from 8.2×10−10 to 2.5×10−8 M Ru was obtained by the initial rate procedure. Influence of 30 foreign ions was considered. Ru in ore samples was analysed by this method, with satisfactory results.

Investigations of the excitation energy transport mechanism in donor-acceptor systems

Measurements of fluorescence quantum yield ηD/ηoD of Na-fluorescein (donor; D) versus concentration of rhodamine B (acceptor; A) in viscous solutions have been carried out. The donor concentration in these solutions was as follows:C D=2·10(-2) M (system I), 1.5·10(-2) M (II), 10(-2) M (III), 3·10(-3) M (IV), and 5·10(-5) M (V). The experimental results have been compared with current theories of nonradiative electronic energy transfer (NEET). In the case of very strong migration (systems I, II, and III), a significant influence of correlations (between configurations of D and A molecules in the surroundings of successively excited donors) on quantum yield ηD/ηoD has been determined. Experimental values have been found to be clearly higher in comparison with those predicted theoretically. The influence of possible factors on the decrease in the effectiveness of excitation energy transport to traps-acceptors in systems of very strong migration has been discussed.

On the use of fluorescent dyes for concentration measurements in water flows

An experiment was performed to evaluate the characteristics of various fluorescent dyes used as tracers for concentration measurements in water flows, by laser induced fluorescence. Three common fluorescent dyes (fluorescein, rhodamine B and rhodamine 6G) were used, to select the most suitable fluorescent dye and identify its range of linear response. The results showed that, in terms of the stability of the solution, fluorescein is inferior to either rhodamine B or rhodamine 6G and that for concentrations of rhodamine B less than 0.08 mg/1 the response of fluorescent to the incident light is linear.