Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “FLUORESCEINS”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 991 records · Page 55Linked to original sources

Fluorescein angiography in hypertensive pregnancies.

A retrospective study in two university hospitals investigating retinal changes in pregnancies complicated by hypertension, seldom revealed retinal vascular changes in pre-eclamptic toxemia. Fluorescein angiography was performed on 16 severe pre-eclamptic toxemias and 14 chronic hypertension pregnancies. Normal caliber retinal vessels and normal filling time, with no subretinal or subepithelium leakage, was found in all pre-eclamptic toxemic patients. Four out of the 14 chronic hypertensive patients showed signs of mild hypertensive retinopathy. A review of the literature on fluorescein angiography in pregnancy showed that vascular changes in pre-eclamptic toxemia are choroidal rather than retinal.

Adult↗

Monitoring of a conjugation reaction between fluorescein isothiocyanate and myoglobin by capillary zone electrophoresis.

The conjugation reaction between the amine reactive fluorescent probe fluorescein isothiocyanate and the protein horse heart myoglobin was directly monitored as the reaction progressed by capillary zone electrophoresis with UV absorbance detection. Kinetic analysis of the data indicated that the order of the reaction was first with respect to myoglobin and 1.3 with respect to fluorescein isothiocyanate. The separation of peaks attributable to the incorporation of n = 1,2, ... 7 fluorochrome labels into the protein has some significance for the generation of single-label protein probes, such as antibodies.

Animals↗

The fluorescein-antifluorescein quenching system as a model for assaying changes in antibody function.

A rapid, simple and inexpensive procedure is presented for utilizing the fluorescein-antifluorescein quenching reaction as a model system to monitor and evaluate changes in antibody function brought about by conjugation and modification procedures. Experiments showing 1) the gradual loss of antigen-binding activity during dinitrophenylation, 2) the partial loss and subsequent recovery of activity during the reversible blocking of amino groups by citraconylation and 3) the quantitative release of bound fluorescein during guanidine denaturation were performed to demonstrate the versatility of the model.

Animals↗

Direct fluorescent labeling of cells with fluorescein or rhodamine isothiocyanate. I. Technical aspects.

A rapid and simple method of cell labeling by stable conjugation with fluorescein or rhodamine is described. Viable cells are incubated under benign conditions (near physiologic pH in normal media) with free fluorescein or tetramethyl rhodamine isothiocyanate, and are adequately separated from unreacted fluorochrome by washing or centrifugation through fetal calf serum. The effects of the pH, the time and temperature of incubation, and the concentration of cells, fluorochrome, and free protein in the media are described. The method labels all cell types, although to different degrees. Fluorescence microscopy reveals fluorescence throughout the cell, although chromatin appears relatively spared. Cellular fluorescence is fairly stable at 4 and 25 degrees C, decays rapidly at 37 degrees C, but is nonetheless visible for days even at this temperature. In the case of lymphocytes, intense fluorescence is obtained without affecting cell viability, and without alteration of the ability to mount a graft versus host response.

Animals↗

Use of fluorescein conjugated staphylococcal protein-A as a labeling agent for porcine lymphocytes.

Staphylococcal Protein-A conjugated to fluorescein (FPA) was compared to a fluorescein conjugated sheep immunoglobulin anti-pig IgG (FSAPG) as a labeling agent for surface IgG positive (sIg+) porcine lymphoid cells. At plateau concentration of the reagents, more lymphoid cells were labeled with FPA than with FSAPG. However, on a protein concentration basis, FPA was less sensitive than FSAPG. As a control, FPA proved to be a poor labeling agent for sIg+ bovine lymphoid cells when compared to FITC conjugated rabbit IgG anti-bovine IgG (FRABG). Adsorptions of porcine lymphoid cells onto Protein-A Sepharose were performed in order to study the differential specificity of the Protein-A for sIg and for free immunoglobulins. The results of such absorptions showed that Protein-A Sepharose, whatever its affinity for Fab fragments from porcine immunoglobulins, could be used to enrich the sIg negative lymphoid cell populations in the pig.

Animals↗

17 alpha-allyl estradiol analogues as candidates for development of high-affinity fluorescein-estradiol conjugates.

In order to develop stable, high-affinity fluorescein-estradiol conjugates, the fluorescein moiety must be leashed to the estradiol molecule at a point which interferes least with estradiol's binding to the receptor. Because of the high affinity of 17 alpha-substituted estradiol (e.g. ethynyl estradiol), we investigated a series of 17 alpha-substituted estradiol compounds to determine the optimal properties of a leash at this position. Twelve estradiol derivatives bearing a three-carbon 17 alpha side chain with or without a terminal functional group and with varying degrees of unsaturation were synthesized. Initial comparison of the receptor binding affinities of some of these derivatives suggested that three factors might reduce affinity: internal hydrogen bonding of the 17 beta-hydroxyl proton with an oxygen atom of the 17 alpha side chain; hydrophilicity of the ligand; or steric interference of the side chain with receptor binding. Further comparisons were designed to evaluate the relative contribution of these factors. The results suggest that the relative affinities of these 17 alpha-substituted estradiol derivatives are influenced primarily by the steric interference of the side chains and also by their hydrophilicity. Internal hydrogen bonding involving the 17 beta-hydroxyl proton does not seem to have a profound effect.

Animals↗

Fluorescein angiography of the fundus: a schematic approach to interpretation.

Fluorescein angiographic patterns reveal a wide variety of anatomical, pathological and physiological information which, correctly interpreted, contributes to the differential diagnosis of fundus diseases and to the evaluation of appropriate therapeutic approaches. A schema for interpretation of the fluorescein angiogram is presented, following a logical progression from the initial determination of abnormal hypofluorescence of hyperfluorescence to the evaluation of the specific locations and features of the patterns, and their relationships to various disorders.

Choroid Neoplasms↗

Elicitation of distinct populations of monoclonal antibodies specific for the variable domains of monoclonal anti-fluorescein antibody 4-4-20.

Armenian hamsters were immunized with non-liganded, partially liganded or affinity-labeled anti-fluorescein Mab 4-4-20. Seventeen hybridoma producing monoclonal anti-4-4-20 antibodies were characterized from chemically-mediated fusions of immune hamster lymphocytes with murine Sp2/O-Ag14 myeloma cells. Distinct populations of anti-4-4-20 monoclonal antibodies were isolated from hamsters receiving immunizations with partially liganded Mab 4-4-20 relative to those receiving affinity-labeled 4-4-20. Two of the three monoclonal antibodies produced in response to partially liganded 4-4-20 were inhibited in their interaction with 4-4-20 by fluorescyl ligand. These two clones, 1F4 and 1B7, recognized unique epitopes on the 4-4-20 molecules, as demonstrated by non-reactivity with members of the 4-4-20 idiotype family. Additionally, 1F4 and 1B7 demonstrated the ability to delay the association of fluorescein with Mab 4-4-20. The 14 characterized non-ligand-inhibitable Mabs elicited to affinity-labeled 4-4-20 were classified into four separate groups based on various binding properties with members of the 4-4-20 idiotype family and binding to resolved H- and L-chains in a western blot. Members of three of the four groups showed strong reactivity with both 04-01 Ig and 04-01 SCA, which utilizes the same L-chain as Mab 4-4-20. Six non-ligand-inhibitable Mabs, 4A6, P1E11, 3A5-1, 2C3, 2C4, and 1A4, delayed the dissociation rate of ligand from Mab 4-4-20 and mutant 4-4-20 SCA L32phe.

Animals↗

Specific modification of Escherichia coli RNA polymerase with monomercury derivative of fluorescein acetate.

The method of specific modification of RNA polymerase with a monomercuric fluorescein derivative, fluorescein-monomercuriacetate (FMMA), is proposed. Under an appropriate condition of modification, FMMA is capable of mercaptid bonding with one of the alpha-subunits. It is shown that covalent modification with FMMA does not affect the kinetic parameters (KB and k2) of RNA synthesis nor does it lead to the inhibition of the overall RNA synthesis. The spectral characteristics of FMMA covalently bound to RNA polymerase were found to be sensitive to some temperature-induced conformational alterations of RNA polymerase, indicating that the labeled enzyme allows study of conformational behaviour of RNA polymerase during its functioning.

Binding Sites↗

A novel fluorescein-histamine reagent to quantitate histamine receptor expression on leucocytes.

The expression of histamine receptors on the surface of rat lymph node cells was studied using a reagent made by directly coupling fluorescein isothiocyanate (FITC) to histamine. This approach contrasts with the use of previous reagents, made by coupling histamine and fluorescein separately to a protein carrier, which bind non-specifically to cells and cause staining unrelated to histamine receptor expression. The new reagent was used, in combination with a panel of monoclonal antibodies, for the dual staining of rat lymph node cells for two-colour flow cytometric analysis to investigate the distribution of histamine receptors on different leucocyte subsets. The majority of cells were stained by the FITC-histamine reagent and these constituted two distinct populations, those with the properties of small lymphocytes and a second population which included macrophages. Inhibition studies with the drugs mepyramine and cimetidine, which are antagonists of H1 and H2 receptors, respectively, showed that most lymphocytes possess H1 receptors while the macrophages have H2 receptors. It seems that macrophages have a higher number of histamine receptors than the majority of lymphocytes, but that they are of lower affinity.

Animals↗

Interaction of fluorescein derivatives with glibenclamide binding sites in rat brain.

In rat brain, [3H]glibenclamide binds with high affinity to sulfonylurea receptors associated with ATP-sensitive potassium (KATP) channels. KATP channels may play a modulatory role in neurotransmitter release and are involved in acute pathological events occurring in the brain. Fluorescein derivatives, which are suitable tools for the labelling of nucleotide binding sites, influence KATP channels and sulfonylurea receptors properties in insulinoma and cardiac cells. In this study, a negative allosteric action of fluorescein derivatives on glibenclamide binding sites has been shown in rat cortical neurons. This supports the hypothesis of interactions between nucleotide- and sulfonylurea-binding sites within the sulfonylurea receptor.

Animals↗

Cyclodextrin-bound 6-(4-methoxyphenyl)imidazo[1,2-alpha+/-]pyrazin-3(7H)-ones with fluorescein as green chemiluminescent probes for superoxide anions.

In providing chemiluminescent probes that have high chemiluminescence intensity and high specificity to superoxide anions, novel chemiluminescent probes involving cyclodextrins covalently bound to 6-(4-methoxyphenyl)imidazo[1,2-alpha]pyrazin-3(7H)-one with fluorescein were synthesized and characterized. Using the hypoxanthine-xanthine oxidase system for the generation of the superoxide anions, these novel chemiluminescent probes showed higher superoxide-induced chemiluminescence intensity than that of 6-[4-[2-[N(')-(5-fluoresceinyl)thioureido]-ethoxy]phenyl]-2-methylimidazo[1,2-alpha]pyrazin-3(7H)-one (FCLA). When tested at a probe concentration of 1.0 microM, compound 6, in which 6-(4-methoxyphenyl)imidazo[1,2-alpha]pyrazin-3(7H)-one and fluorescein are covalently attached on the secondary and primary hydroxyl faces of gamma-cyclodextrin, respectively, showed green luminescence intensity that was 26 times that of FCLA, which was also the highest luminescence intensity in this present study. At probe concentrations of less than 1.0 microM, the ratio of the superoxide-dependent chemiluminescence intensity to the background chemiluminescence intensity for compound 6 was higher than that of FCLA. This high superoxide-induced chemiluminescence intensity and superoxide specificity in low probe concentrations indicates that 6 can be more effective than FCLA toward the measurement of superoxide anions.

Cyclodextrins↗

Time-resolved fluorescence resonance energy transfer kinase assays using physiological protein substrates: applications of terbium-fluorescein and terbium-green fluorescent protein fluorescence resonance energy transfer pairs.

Fluorescence-based kinase assays using peptide substrates are an established format for high-throughput screening and profiling of kinases. Among fluorescence-based formats, time-resolved fluorescence resonance energy transfer (TR-FRET) using a lanthanide donor species has advantages over other fluorescent formats in being resistant to many types of optical interference such as autofluorescent compounds, scattered light from precipitated compounds, or colored compounds that absorb excitation or emission radiation ("color quenchers"). By taking advantage of the fact that acceptors such as fluorescein or green fluorescent protein (GFP) can be paired with a terbium donor in a TR-FRET assay, we have developed TR-FRET kinase assays that use physiologically relevant native protein substrates, either labeled with fluorescein or expressed as GFP fusions. Phosphorylation of the labeled protein substrate results in an increase in TR-FRET when incubated with a terbium-labeled antibody that specifically recognizes the phosphorylated product. Thus, a strategy of using terbium-based TR-FRET can be applied to develop kinase assays, and the unique properties of terbium lead to a high degree of flexibility with regard to specific assay design.

Animals↗

Retinal blood flow analysis using intraoperative video fluorescein angiography combined with optical fiber-free intravitreal surgery system.

PURPOSE: To report a new method to perform intraoperative video fluorescein angiography (VFA) using an optical fiber-free intravitreal surgery system (OFFISS) and retinal blood flow analysis during surgery. DESIGN: Observational case series. METHODS: Four eyes of four patients with macular edema as a result of branch retinal vein occlusion underwent vitrectomy and intraoperative VFA with a bolus of 0.8 ml fluorescein dye. The segmental blood flow was calculated using dye dilution technique. Intraocular pressure was maintained at 15 mm Hg. RESULTS: The VFA was clearly recorded with stable excitation light and very little eye movement under retrobulbar anesthesia. The segmental blood flow of the affected vessels (6.1 +/- 1.2 pixel(2)/s) was significantly lower than that of the healthy vessels (17.9 +/- 7.9 pixel(2)/s) (P < .05). CONCLUSION: The combination of VFA and OFFISS can facilitate intraoperative VFA, and may be useful for evaluating retinal blood flow during surgery.

Aged↗

Cystoid macular edema in gyrate atrophy of the choroid and retina: a fluorescein angiography and optical coherence tomography evaluation.

PURPOSE: To analyze the importance f optical coherence tomography (OCT) to diagnose the cystoid macular edema in a case of gyrate atrophy. DESIGN: Observational case report. METHODS: A 12-year-old boy presenting with gyrate atrophy of the choroid and retina underwent ophthalmologic, clinical, and laboratory tests. RESULTS: Plasma ornithine level was 735 mumol/l. Fluorescein angiography showed bilateral hyperfluorescence involving the central region of the macula. Optical coherence tomography (OCT) disclosed bilateral intraretinal cysts areas of low reflectivity with occasional high-signal elements bridging the retinal layers and intraretinal thickening. CONCLUSIONS: Both fluorescein angiography and OCT were helpful to confirm the diagnosis of macular involvement as a complication of gyrate atrophy of the choroid and retina in a patient who presented without any clinical evidence of cystoid macular edema, except a decrease in visual acuity.

Child↗

Marx line: fluorescein staining line on the inner lid as indicator of meibomian gland function.

PURPOSE: To determine whether the location of a fluorescein-stained line, the Marx line (ML), which runs along the inner eyelid, is correlated with meibomian gland function. DESIGN: Prospective observational case series. METHODS: After applying fluorescein dye solution to the eye, the ML score was calculated for the outer, middle, and inner thirds of the lower eyelid margin. ML scoring was as follows: 0, entirely on the conjunctival side of the meibomian orifices (MOs); 1, part of the ML touches the MOs; 2, ML runs through all of the MOs; and 3, ML runs on the eyelid-margin side of the MOs. Correlations were calculated between the total ML score and age for 251 randomly recruited subjects without acute ocular surface diseases, and between age and the ML score for the three regions of the lower eyelid. Correlations between the regional ML score and the meibographic score, and the meibomian gland secretion score were also determined. The total ML scores of 15 subjects without meibomian gland dysfunction (MGD) were compared with 15 age-matched patients with MGD. RESULTS: The three regions of the lower eyelid had significantly different ML scores. Strong correlations were found between the ML score and age, the meibographic score, and the meibomian gland secretion score. The total ML score of MGD group was significantly higher than that of the non-MGD group. CONCLUSIONS: The strong correlation between the ML score and the meibomian gland scores indicates that the ML score can be used as a simple and rapid screening score for meibomian gland function.

Adult↗

Separation of polyethylene glycols and their fluorescein-labeled compounds depending on the hydrophobic interaction by high-performance liquid chromatography.

The separation and characterization of fluorescein-labeled polyethylene glycols (PEG) is described. Firstly, the polyethylene glycols labeled with fluorescein isothiocyanate (FITC) were synthesized and separated using Sephadextrade mark LH-20 medium by a step gradient. Secondly, a TSK GEL G4000 PW XL column was developed for determining the FITC derivatives of PEG. The retention mechanism is based on the hydrophobic interaction between the FITC derivatives of PEG and the packing material of the TSK GEL G4000PW XL column. The retention time of the PEG compounds increased by adding of salts in the mobile phase and decreased by adding of organic modifier. In addition, various salts in the eluent can also change the chromatographic behavior of these compounds. Finally, the pH of the mobile phase can have an impact on the retention time of the PEG compounds.

Chromatography, High Pressure Liquid↗

Effect of nucleotide P2Y2 receptor agonists on outward active transport of fluorescein across normal blood-retina barrier in rabbit.

BACKGROUND: To evaluate the effect of nucleotide P2Y(2) receptor agonists INS542 and uridine 5'-triphosphate (UTP) on the outward active transport of fluorescein across rabbit blood-retina barrier (BRB) in vivo. METHODS: Injection (0.1 ml) of INS542 (0.1 or 1mM), phosphate buffered solution, or UTP (1 or 10mM) was made in Dutch-belted rabbits. Differential vitreous fluorophotometry (DVF) was performed 3hr later and the fluorescein (F)/fluorescein monoglucuronide (FG) ratio was then calculated. F/FG ratios are inversely proportional to outward active transport of F across BRB at the level of the retinal pigment epithelium (RPE). In another set of experiments, the effect of 0.1 ml vitreous injection of INS542 (1mM) on F/FG ratios was evaluated at different time points ranging from 0.5 to 48hr before conducting DVF. RESULTS: F/FG ratios obtained 3hr after intravitreal injection were as follows (mean+/-standard error): 0.49+/-0.14 (0.1mM INS542), 0.19+/-0.04 (1mM INS542), 0.48+/-0.09 (PBS), 0.40+/-0.08 (1mM UTP) and 0.36+/-0.05 (10mM UTP). The F/FG ratio for 1mM INS542 was significantly lower than in the other groups (P<0.05). In the time course experiments, a significant decrease in the F/FG ratios was observed between 1 and 12hr following administration of INS542 when compared with F/FG ratios obtained in the contralateral (untreated) eye. CONCLUSION: Intravitreal administration of INS542 (but not UTP) enhances outward active transport of F across RPE in intact rabbit eye, indicating that activation of P2Y(2) receptors in vivo directly stimulates RPE active transport.

Animals↗