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At least 1,369 records · Page 76Linked to original sources
PubMed1957

Staining toxoplasma gondii with fluorescein-labelled antibody. II. A new serologic test for antibodies to Toxoplasma based upon inhibition of specific staining.

A new serologic test for antibodies to Toxoplasma is described, which is based upon inhibition of specific staining with fluorescent antibody. In performing the test, a mixture of the test serum and known fluorescein-labelled antiserum is added to a dried smear of toxoplasms for 1 hour at 37 degrees C. The smear is then rinsed and examined with a fluorescence microscope. Reduction in the brightness of fluorescence, as compared to that of a negative control slide, indicates the presence of antibody in the test serum. A comparison of the results of this test with those of the methylene blue dye test showed a strong parallelism between the two sets of results. On the other hand, the complement-fixation test for toxoplasmosis did not yield nearly as many positives as the inhibition test. The specificity of the new test was studied by comparing it with dye test results and clinical histories in human patients, and by testing a group of animals immunized with a variety of non-Toxoplasma antigens. No evidence of cross-reactions was obtained in the latter series. Some advantages and disadvantages of the inhibition test are discussed.

Animals↗
PubMed1994

The effect of age on the penetration of fluorescein into the human eye.

The penetration into the eye of fluorescein from a normal drop was found to increase with age and averaged twelve times more in the elderly than in the young. Examination of the literature suggests that this is a result of a greater contact time with the cornea rather than a rise in epithelial permeability.

Adolescent↗
PubMed1994

Patterns of intracellular compartmentalization, trafficking and acidification of 5'-fluorescein labeled phosphodiester and phosphorothioate oligodeoxynucleotides in HL60 cells.

We have examined the intracellular compartmentalization and trafficking of fluorescein labeled (F) phosphodiester (PO) and phosphorothioate (PS) oligodeoxynucleotides (oligos) in HL60 cells. A series of F-oligos (PO and PS) were incubated for 6 hrs. with HL60 cells and the mean intracellular fluorescence determined by flow cytometry. The F signal was normalized by the addition of the ionophore monensin. An increase in signal intensity following addition of monensin indicated that the oligo was resident in an acidic intracellular environment. F-PS, but not F-PO oligos were found to reside in an acidic environment. An exception was a PO homopolymer of 15 cytidine bases (FOdC15) which was acidified. Using two different methods, the average resident intracellular pH of F-PS oligos and F-OdC15 was shown to be approximately 1 pH unit lower than that of F-PO oligos. Acidification of F-PS oligos could be blocked by the antibiotic bafilomycin, indicating that acidification was occurring in endosomes or vacuoles. F-PO and F-PS oligos were effluxed from HL60 cells from two intracellular compartments. However, approximately 60% of internalized F-PO oligo resided in a 'shallow' compartment that was turned over rapidly (t1/2 = 5-10 min.) whereas only 20% of F-PS oligo resided in this compartment. Conversely, approximately 80% of the internalized F-PS oligo but only 40% of F-PO oligo resided in a 'deep' compartment that turned over with t1/2 = 2-5 hrs. This report is the first quantitative demonstration that PO and PS oligos, and PO oligos of different sequences are trafficked differently by HL60 cells.

Cell Line↗
PubMed1997

Use of fluorescein-labeled oligonucleotide for analysis of formation and dissociation kinetics of T:A:T triple-stranded DNA: effect of divalent cations.

The formation and dissociation kinetics of homonucleotide oligo(dT):oligo(dA):oligo(dT) triplex have been analyzed by fluorescence measurements of fluorescein-labeled oligo(dT) providing considerably higher sensitivity to monitoring reaction kinetics than traditional hypochromicity and circular dichroism. The triplex is concluded to be formed by a bimolecular process corresponding to the addition of the oligo(dT) strand to a preserved oligo(dT):oligo(dA) duplex. The association rate was found to be faster the higher the divalent cation concentration and depends upon the nature of divalent ions in the following order of efficiency: Mn2+ > Mg2+ > Ni2+, Ca2+ > Ba2+. The more efficient metal ions for the triplex formation were found also more efficient for the stabilization. The dissociation kinetics of the third Hoogsteen-bound strand was monitored at below melting temperature by chasing the labeled dT strand from the triplex by excess of non-labeled oligonucleotide. The dissociation rate was found to be almost independent of concentration and nature of cation. The thermodynamic stabilization of triplex by cations is thus a consequence of the increased formation rate.

Cations, Divalent↗
PubMed1992

Conversion of pyridylamino sugar chains to 1-amino-1-deoxy derivatives, intermediates for tagging with fluorescein and biotin.

Pyridylamino (PA) derivatives of sugar chains were converted to 1-amino-1-deoxy derivatives. PA-lactose as a model compound was reduced with hydrogen, then treated with hydrazine. The product obtained was identified as 1-amino-1-deoxylactitol by mass spectrometry and chromatography with 1-amino-1-deoxylactitol as standard. PA-N-acetylglucosamine was converted to 1-amino-1-deoxy-N-acetylglucosaminitol under the same conditions. As an application, Man alpha 1-6(Man alpha 1-3)Man alpha 1- 6(Man alpha 1-2Man alpha 1-3)-Man beta 1-4GlcNAc beta 1-4GlcNAc-PA was converted to the 1-amino-1-deoxy derivative, which was further derivatized with fluorescein isothiocyanate or biotin sulfo-N-hydroxy-succinimide ester. Binding of these derivatives to concanavalin A dot-blotted on a nitrocellulose membrane was confirmed by fluorescence and by streptavidin-peroxidase conjugate. This conversion allowed replacement of the PA-group in PA-sugar chains which can be easily purified from glycoconjugates.

Amino Sugars↗
PubMed1981

Preparation of biologically active fluorescent heparin composed of fluorescein-labeled species and its behavior to antithrombin III.

A hog-mucosal heparin purified gel-chromatographically (total sulfate, 2.20; N-sulfate, 0.82; N-acetyl, 0.15 (mol/mol HexN); activity, 184 USP units/mg) was partially N-desulfated to give a product (total sulfate, 2.12; N-sulfate, 0.71 (mol/mol HexN); activity, 159 USP units/mg). The free amino groups in the product was extensively labeled with fluoresceinylthiocarbamoyl (FTC) groups, and the labeled product was chromatographed on Octyl-Sepharose CL-4B to give a heparin preparation of fluorescein-labeled species (total sulfate, 2.04; N-sulfate, 0.72; degree of substitution, 0.059 (mol/mol HexN); activity, 155 USP units/mg). The fluorescent heparin thus obtained was indicated from its analytical data to have one FTC group pr heparin molecule irrespective of the molecular weight. The fluorescent heparin was separated into the low-affinity (56.6%) and high-affinity (43.4%) fractions for antithrombin III, and the anticoagulant activities of the two types of fluorescent heparin were compared with those of the starting heparin and the partially N-desulfated heparin, suggesting that FTC-substitution in heparin molecules had no effect on the known biological interaction with mobilized or immobilized antithrombin III.

Animals↗
PubMed1977

Principles of fluorescein angiography.

There are two barriers between the blood and retina--one in the retinal circulation at the endothelial cell lining with its tight junctions in the retinal capillaries, and the second involving the choroidal circulation at the zonula occludens between adjacent retinal pigment epithelial cells. Damage to either of these barriers results in a leakage of fluid into or beneath the sensory retina. Serous detachment of the retinal pigment epithelium is a special situation in which both barriers remain intact but fluid accumulates in the space between the detached pigment epithelial cells and Bruch's membrane. It is convenient to analyze the fluorescein angiographic findings in relation to these two barriers, as a large number of retinal disorders affect either the retinal vascular system or the choriocapillaris-Bruch's membrane-pigment epithelium layers.

Capillaries↗
PubMed1977

Fluorescein angiography: techniques and toxicity.

Fluorescein angiography is a safe, well-standardized procedure for establishing fundus abnormalities. It facilitates documentation of the finest detail of the fundus, allows estimation of the blood flow through the retina, and permits the doctor to evaluate the integrity of the retinal vessels. When there is good communication between doctor and patient, and between doctor and photographer, it is an especially useful procedure.

Emergency Medical Services↗
PubMed1992

The intraoperative localization of the obscure bleeding site using fluorescein.

Despite visceral angiography and radiolabeled gastrointestinal scintigraphy, the localization of gastrointestinal bleeding can still be a challenge. Even preoperative localization with visceral angiography is no guarantee of successful intraoperative localization or subsequent pathological confirmation. We report a case of obscure gastrointestinal bleeding of small bowel origin, which was localized intraoperatively by fluorescein injected via a superselectively placed catheter.

Angiography↗
PubMed1985

Effects of fluorescein on tear breakup time and on tear thinning time.

A simple, noninvasive method of in vivo precorneal tear film stability analysis is described. The method involves observing the first catoptric (first Purkinje) image. The effect of fluorescein on the results and the relation with standard tear breakup time (BUT) are presented.

Adult↗
PubMed1991

Corneal staining after sequential instillations of fluorescein over 30 days.

The corneal staining patterns of 6 healthy female subjects were monitored Monday through Friday for 4 consecutive weeks using daily sequential instillations of fluorescein. The patterns showed that in these subjects there was no predictable pattern of staining, that each subject had different staining characteristics, and that corneal staining varied day to day.

Cornea↗
PubMed1997

Sequential staining: the effects of sodium fluorescein, osmolarity, and pH on human corneal epithelium.

BACKGROUND: Previous reports have suggested that sequential applications of sodium fluorescein (NaF) to the ocular surface cause loss of epithelial cells. In those experiments the solutions were free of preservatives, but delivered a hypertonic and alkaline load. It is possible that either the hyperosmolarity, NaF, and/or alkalinity may have contributed to the epithelial cell loss. Our study explored the possible impact of these three factors on epithelial integrity. METHODS: We used a paradigm in which we designed four test solutions to isolate the cytotoxic effects of the three factors. Fifteen subjects were exposed to one of the solutions on separate visits. One solution was instilled in both eyes, every 3 min, for a total of seven applications, and a slitlamp examination was performed. Staining was graded on a scale of 0 to 3 for each of five corneal sectors. RESULTS: Application of solution 1 (NaF, hyperosmotic, and alkaline) resulted in staining for all subjects. For the other three solutions (without NaF), insignificant staining occurred. CONCLUSIONS: The epithelium tolerates changes in pH and osmolarity between 7.2 to 7.8 and 290 to 350, respectively. However, NaF when applied in multiple doses may be cytotoxic.

Administration, Topical↗
PubMed1980

Quantification of tissue fluorescein delivery and prediction of flap viability with the fiberoptic dermofluorometer.

Quantitative fluorescence assessment with the fiberoptic dermofluorometer has been introduced to overcome the inadequacies of ultraviolet inspection following intravenous administration of fluorescein. Initial applications in the pedicle flap of the rat have indicated that this method can predict flap viability with reproducible precision and accuracy. This minimally invasive technique should be of considerable assistance to the evaluation of hypoperfused states in laboratory and clinical situations.

Animals↗
PubMed1989

Flash fluorometer made from off-the-shelf photographic equipment to measure tissue levels of fluorescein.

A device to measure fluorescein in tissue has been constructed from standard photographic equipment--an electronic strobe and a flashmeter both covered with interference filters. The instrument works well in the light and need not touch the area being measured, an advantage over existing fluorometers. The instrument has been used to measure the amount of dye in flaps in rats, pigs, and three humans. The results revealed that the amount of dye in a freshly made flap was rarely as much as in normal skin, and skin with less than 20 percent of the dye of control areas usually sloughed, although there were exceptions. In the future the instrument will be improved, and its readings will be compared to those obtained from radioactive microspheres, the present "gold standard" of techniques to measure vascularity. The instrument can be used to estimate the blood supply to any tissue and seems to be as reliable as the dermofluorometers already on the market.

Animals↗
PubMed1998

Peripheral retinal evaluation comparing fundus photographs with fluorescein angiograms in patients with diabetes mellitus.

PURPOSE: To evaluate peripheral nonproliferative retinopathy by comparing fundus photograph changes with angiographic findings in type 1 diabetic patients with a long duration of diabetes. METHODS: Thirty-eight patients with type 1 diabetes, without proliferative retinopathy and with at least 30 years of diabetes duration, were selected to be examined with fundus photography and fluorescein angiography. Two levels of retinopathy degree were identified. In fundus photographs, level 1 represented eyes with no or mild peripheral background retinopathy (i.e., five or fewer pinpoint hemorrhages or microaneurysms), and level 2, peripheral moderate retinopathy (i.e., dot-and-blot hemorrhages or intraretinal microvascular abnormalities or cotton-wool spots). In the angiograms, level 1 represented a nearly normal vascular pattern with occasional microaneurysms and level 2 comprised morphologic signs of abnormal circulation such as dilated capillaries, arteriolar abnormalities, intraretinal microvascular abnormalities, and capillary loss of 3 or more disk diameters from the center of the macula. The angiograms and fundus photographs were graded separately and the results of the grading were compared. RESULTS: The peripheral parts of the retina could be visualized with a high photographic quality on both fundus photographs and angiograms in 66 eyes. On fundus photographs, both graders found level 1 retinopathy in 47 of 66 eyes and level 2 retinopathy in 13 of 66 eyes. On angiograms, both graders found level 1 retinopathy in 46 of 66 eyes, whereas level 2 retinopathy was seen in 16 of 66 eyes. In most eyes with no or mild retinopathy, the angiograms were interpreted as nearly normal (41 of 47), and in most eyes with moderate retinopathy, they were interpreted as abnormal (10 of 13). CONCLUSION: The degree of peripheral diabetic retinal changes based on grading of fundus photographs was comparable to that based on angiograms in 51 of 66 (77%) eyes.

Adult↗
PubMed2000

Clinicopathologic correlation of fluorescein and indocyanine green angiography in exudative age-related macular degeneration.

PURPOSE: To correlate the clinical and histopathologic features of an eye with age-related macular degeneration studied with fluorescein (FA) and indocyanine green (ICG) angiography 4.5 months before the patient's death. METHODS: Histopathologic features from serial sections through the macula of a 76-year-old man with occult choroidal neovascularization (CNV) were reconstructed in a scaled two-dimensional map and compared with FA and ICG angiogram images obtained 4.5 months before his death. RESULTS: The region of prior laser photocoagulation was identified as a well-demarcated hypofluorescent region in the early frames of the FA and the early and late phases of the ICG angiogram. This corresponded histopathologically to a well-circumscribed area of absence of the choriocapillaris, loss of the outer retina and retinal pigment epithelium, and scarring of the choroid. Occult CNV characterized by elevated late hyperfluorescence on the FA and intense well-defined hyperfluorescence on the ICG angiogram corresponded to a thick fibrovascular membrane in the subretinal space and within Bruch's membrane. Thin extensions of both the subretinal and intra-Bruch's membrane fibrovascular membrane components corresponded to nonelevated stippled late hyperfluorescence on the FA and mild late hyperfluorescence on the ICG angiogram. CONCLUSION: Histopathologic mapping revealed a large fibrovascular complex located subretinally and within Bruch's membrane with thin and thick components that correlate well with findings of occult CNV on FA and ICG angiography.

Aged↗
PubMed1985

Induction and suppression of contact sensitivity to fluorescein isothiocyanate (FITC).

Although both fluorescein isothiocyanate (FITC) and trinitrophenyl (TNP) covalently couple primarily to the epsilon-amino group of lysine residues of surface glycoprotein, FITC is structurally different from TNP. In this paper, we investigated the immune regulatory mechanisms in contact sensitivity (CS) to FITC by the administration of FITC and FITC-conjugated epidermal cells (FITC-EC) via various routes. Mice injected with FITC via i.p. or i.v. route did not induce CS but induced hyporesponsiveness to the following sensitization with FITC painting. Mice injected with FITC via s.c. route induced neither CS nor hyporesponsiveness to the following FITC painting. Administration of FITC via i.v. route was demonstrated to induce hapten-specific suppressor T cells. Inoculation of FITC-EC via s.c. or i.p. route induced CS, whereas injection of FITC-EC via i.v. route did not induce CS but induced hyporesponsiveness to the following FITC painting. The results are compared with the previous data obtained by trinitrobenzene sulfonate and trinitrophenyl-conjugated epidermal cells.

Animals↗