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PubMed1981

Monitoring tissue elimination of fluorescein with the perfusion fluorometer: a new method to assess capillary blood flow.

Visual assessment of tissue staining after intravenous fluorescein is a common technique for predicting viability of questionably perfused tissue. The development of the perfusion fluorometer has permitted quantification of tissue fluorescein, providing increased precision. This study employed this instrument to calculate fluorescein elimination from rats with and without raised dorsal pedicle flaps. Control animals exhibited homogeneous patterns of fluorescein elimination consistent with first-order kinetics. Elimination in experimental animals was assessed after the animals received full back skin flaps with the cephalad pedicle remaining intact. Three distinct patterns of elimination were noted in each flap. In the cephalad portion, elimination was similar to control. At the caudad end, no elimination was noted. Midflap, fluorescein was eliminated slowly. These elimination patterns predicted ultimate viability 14 days postoperatively, as they correspond to viable, dystrophic, and transitional sections, respectively (P less than 0.001). We conclude that perfusion fluorometry can assess capillary flow in healthy and ischemic tissue by documenting elimination as well as delivery of fluorescein.

Animals↗
PubMed1978

Receptors for fluoresceinated human thyroglobulin in peripheral blood lymphocytes.

Fluoresceinated human native and desialylated thyroglobulin were incubated with peripheral blood lymphocytes. 1% of the lymphocytes, in twenty samples from normal human blood donors, showed a bright granular fluorescence where neither the number nor pattern of fluorescence differed from lymphocytes from the blood of thyroiditis patients. Fluoresceinated albumin and gamma-globulin did not bind to the lymphocytes, and a 500-fold excess of native non-fluoresceinated thyroglobulin inhibited the binding and pre-incubation with anti-IgM serum abolished it. Binding with desialylated thyroglobulin was negligible, and the pattern of fluorescence was pale and uniform. Analysis by sucrose gradient centrifugation and double diffusion in agar gel showed that fluorescein dissociates thyroglobulin into 12S fragments and reduces its immunoreaction with autoantibodies. It can therefore be concluded that the 12S molecule produced by fluoresceination maintains its determinants for lymphocyte receptors, whereas further dissociation, as in desialylated fluoresceinated thyroglobulin, leads to a marked reduction in the binding with lymphocytes.

Binding Sites, Antibody↗
PubMed1993

Intraoperative fluorescein angiography.

BACKGROUND: Fluorescein angiography is often beneficial in the evaluation and management of many retinal vascular diseases. However, vitreous blood or opacities may prevent fluorescein studies before pars plana vitrectomy. After vitrectomy, fluorescein angiography may be delayed, creating uncertainty over differentiation of preoperative, intraoperative, and postoperative findings. METHODS: The authors have modified an intraocular light source and operating microscope to perform intraoperative fluorescein angiography easily. Twenty-five patients underwent fluorescein angiography during pars plana vitrectomy. All studies were recorded using a microscope-mounted video camera for intraoperative and postoperative evaluation. RESULTS: In all cases, intraoperative angiography was performed without complication. Indications for intraoperative studies included confirmation of macular edema, delineation of avascular retina, and localization of retinal and choroidal neovascularization. All videotape recordings of procedures were of high quality, allowing easy review and interpretation. CONCLUSION: Intraoperative fluorescein angiography is an easily performed adjunctive diagnostic procedure that can aid intraoperative evaluation and treatment of selected retinal vascular disorders.

Adult↗
PubMed1997

Visualization of retinal and choroidal blood flow with fluorescein leukocyte angiography in rabbits.

PURPOSE: To visualize the retinal and choroidal leukocytes in rabbits with a new technique, fluorescein leukocyte angiography using a scanning laser ophthalmoscope. METHODS: Blood was withdrawn from an ear vein of a rabbit (New Zealand White), mixed with fluorescein dye in a test tube and centrifuged. The yellow-brown coat layer containing fluorescein-stained leukocytes was collected and injected into the ear vein of the same rabbit while performing fluorescein angiography with a scanning laser ophthalmoscope. The angiographic image displaying circulating fluorescent leukocytes in retinal and choroidal vessels was recorded on a videotape. RESULTS: Fluorescent leukocytes were clearly visible in the retinal arteries, capillaries, veins and choroidal vessels for more than 1 h. Plugging of leukocytes was seen throughout this period of time in choroidal vessels, while plugging was rare in retinal vessels. CONCLUSIONS: Fluorescein leukocyte angiography is a new technique which can be used for visualization of the leukocytes in retinal and choroidal vessels non-invasively and in vivo.

Animals↗
PubMed1989

Intravenous fluorescein interference with clinical laboratory tests.

The results of laboratory tests performed after fluorescein angiography may be erroneous because of interference by intravenous fluorescein. We investigated this potential interference in four adults at intervals of five minutes, three hours, six hours, and 12 hours after fluorescein injection. We used a panel of serum and urine chemistry tests on seven commonly used instruments. A significant change in the reported concentration of a serum or urine analyte was defined as a result beyond +/- 3 coefficients of variation of the preinjection baseline value for the test on a specific instrument. The determinations of creatinine, total protein, cortisol, digoxin, quinidine, and thyroxine in serum were affected by intravenous fluorescein. The urine tests were unaltered. The physician must be aware of the problem of interpreting clinical chemistry results after fluorescein angiography.

Adult↗
PubMed1995

Simultaneous indocyanine green and fluorescein angiography.

PURPOSE: To facilitate the interpretation of the choroidal dye filling sequence, the use of simultaneous indocyanine green (ICG) and fluorescein angiography was evaluated. METHODS: A single-wavelength scanning laser ophthalmoscope (SLO) was modified to a two-wavelength system, permitting the simultaneous recording of ICG and fluorescein angiography. This method has been used in 340 cases. About two thirds of the patients had well-defined or occult choroidal neovascularization (CNV) in age-related macular degeneration (AMD). RESULTS: Simultaneous ICG and fluorescein angiography is feasible with a two-wavelength SLO and provides images of good quality. Two corresponding ICG and fluorescein angiography pictures can be presented as one combined red-green picture. CONCLUSION: This method has three advantages: (1) it allows a precise comparison of the transit of both dyes through both circulations, and there are no differences in the injected bolus nor in the actual blood pressure; (2) the important features of the ICG angiograms are fully aligned with the critical retinal vascular landmarks provided by the fluorescein images; and (3) it is very time efficient--with a single injection and one photographic session, immediate results are obtained.

Adult↗
PubMed1994

Argon laser photocoagulation of fluorescein stained retina--an unrecognised hazard?

Sodium fluorescein staining of the retina following fluorescein angiography may affect the absorption characteristics of argon ion laser photocoagulation. This hypothesis was investigated by performing laser photocoagulation on control and fluorescein stained porcine retinas. The resultant damage was viewed by scanning electron microscopy. In both specimens, argon irradiation produced damage to the pigment epithelium and overlying photoreceptor layer. The control sample showed a deep cylindrical burn, indicative of internal heating, in both retina and choroid. The fluorescein stained sample showed damage consistent with thermal interaction from the surface downwards leaving the choroid relatively spared. This preliminary study demonstrates that fluorescein staining of the retina changes the absorption site of argon laser light and this subject clearly merits further investigation.

Animals↗
PubMed1992

Encapsulation of sodium fluorescein for dye release studies.

Recent investigations have detailed a selective dye release technique in which a pulse of laser light induces the release of a fluorescent dye from temperature-sensitive liposomes circulating in the retinal vasculature. This dye release technique has made possible a new method for measuring ocular blood flow in the retina and has spurred the development of repetitive, site-specific angiography. However, sodium fluorescein, the dye employed clinically for angiography of the retina, has not been employed in the aforementioned studies because of its rapid efflux from liposomes. This report outlines a method for stable encapsulation of sodium fluorescein in temperature-sensitive liposomes. Heat-induced leakage of the dye from liposomes in vitro was similar to that previously seen with other fluorescent dyes. Furthermore, after intravenous injection of encapsulated fluorescein in a nonhuman primate, dye released by a pulse of laser light allowed excellent visualization of the retinal architecture. These results indicate that sodium fluorescein, a dye that has proven to be the agent of choice for sensitive detection of leakage of vessels of the retina, can be released at a specific site in the retinal vasculature. Direct comparisons of the diagnostic capability of free and encapsulated sodium fluorescein are now possible.

Animals↗
PubMed1991

Classification of diabetic retinopathy from fluorescein angiograms. ETDRS report number 11. Early Treatment Diabetic Retinopathy Study Research Group.

The Early Treatment Diabetic Retinopathy Study included use of nonsimultaneous stereoscopic fluorescein angiography to assess severity of characteristics such as capillary loss and fluorescein leakage and to guide treatment of macular edema. Two 30 degrees photographic fields were taken, extending along the horizontal meridian from about 25 degrees nasal to the disc to about 20 degrees temporal to the macula, and a classification system was constructed to allow assessment of selected characteristics. This classification system relies on comparisons with standard and example photographs to evaluate the presence and severity of capillary loss and dilatation, arteriolar abnormalities, leakage of fluorescein dye (including characterization of source), abnormalities of the retinal pigment epithelium, cystoid changes, and several other features. The classification is described and illustrated and its reproducibility between graders assessed by calculating percentages of agreement and kappa statistics for duplicate gradings of baseline angiograms. Agreement was substantial (weighted kappa, 0.61 to 0.80) for severity of fluorescein leakage and cystoid spaces, and moderate (weighted kappa, 0.41 to 0.60) for capillary loss, capillary dilatation, narrowing/pruning of arteriolar side branches, staining of arteriolar walls, and source of fluorescein leakage (microaneurysms versus diffusely leaking capillaries).

Adolescent↗
PubMed1990

Ocular effects and detection in tears of aerosolized intranasal cocaine and fluorescein.

Ocular effects of intranasal cocaine were investigated. Twenty-nine outpatients from an otolaryngology clinic received 1 mL of aerosolized cocaine 4% (40mg) in each nostril. Intraocular pressure, corneal sensitivity, pupil size, and tear cocaine concentration were assessed before and after cocaine administration. Pupil size was unchanged; intraocular pressure increased in 75% of patients (not statistically significant). Corneal sensitivity decreased by 11% (P less than .05). Cocaine, however, was not detectable in tears using high-performance liquid chromatography. Since corneal sensitivity decreases after intranasal cocaine administration, it may travel retrograde through the nasolacrimal duct. In addition, three pathways of pharmacologic absorption using fluorescein were explored because of its ease of detection. We measured tear fluorescein concentrations in five patients undergoing intravenous angiograms with fluorescein 25% and in six patients who received aerosolized fluorescein 2% intranasally. Fluorescein concentration was 29 times higher per mg dose in intranasal subjects. This finding suggests that reflux occurs through the nasolacrimal duct.

Administration, Intranasal↗
PubMedDate not supplied

[The effect of angiography with disodium fluorescein on the hemorheologic parameters of diabetics].

Chorioretinal angiography with fluorescein is an auxiliary method widely used in Ophthalmology which enables us to study the blood/humour and blood/retina/choroid interface. The presence of a strange compound in circulation may interfere with blood flow homeostasis. With the aim of studying fluorescein influence in blood rheology, blood samples were drawn before, immediately after and 30 minutes after fluorescein bolus injection; from 10 patients with diabetes mellitus, with or without retinopathy, blood fluidity (hematocrit, erythrocyte aggregation and whole blood viscosity) and erythrocyte membrane functional properties were determined. After fluorescein injection there was erythrocyte hyperaggregation (37.7%, p = 0.004), was detected, hemoglobin concentration (p = 0.039) and hematocrit (p = 0.013) decrease, and a double time increase of methemoglobin concentration (p < 0.001) the erythrocyte membrane hydrophobic region became more rigid (p = 0.016). All these abnormalities normalized after 30 minutes. In conclusion, fluorescein angiography interferes acutely with the hemorheological parameters of patients with diabetes mellitus, with erythrocyte hyperaggregation which could interfere with the microcirculation of these patients.

Aged↗
PubMed2003

Comparison of micro- and mesoporous inorganic materials in the uptake and release of the drug model fluorescein and its analogues.

The uptake of the three species of the drug model fluorescein (fluorescein sodium salt (FNa), fluorescein free acid (F), and fluorescein diacetate (FDA)) by zeolite NaX and the mesoporous zeotype MCM-41 was investigated as well as their release rates into solutions at pH 7 and pH 4.5. UV/Vis analysis was carried out at a wavelength of 490 nm. Uptakes of the sodium salt of 9 % for zeolite X and 14 % for MCM suggest little penetration of the pores. The use of ethanol as the loading solvent for F resulted in little uptake for both zeolitic materials due to the successful competition of the ethanol for binding sites. Use of acetone (weaker proton acceptor) as loading solvent significantly improved the uptake of F to 17 % and 12 % for zeolite X and MCM, respectively, whilst the uptake of FDA in acetone increased still further to 22 % and 17 % for zeolite X and MCM, respectively. Generally there was a large initial release of the fluorescein analogues from the surface of the zeolites with very little further increase over time. The prescence of an esterase enzyme in the release medium of FDA tripled the release from MCM to 15 % but left the release from zeolite X unaffected at 6 %. The results obtained show that uptake of fluorescein and its analogues is dependent on the loading solvent used, the amount released is influenced by not only the solvent but the pH and the presence of enzymes in the release medium.

Journal Article↗
PubMed1980

Tritiated fluorescein binding to normal human plasma proteins.

Aliquots of normal human plasma that had been incubated with tritiated fluorescein were examined for radioactive binding to proteins. Samples were fractionated by polyacrylamide gel electrophoresis (PAGE) and gel filtration. Aliquots removed between zero time and two hours showed no specific radioactive binding peaks by either method. Tritiated fluorescein ran well ahead of all proteins at all times on PAGE and well after the protein eluted from a fractionating column (Sephadex G-75). Ten minutes after intravenous injections, PAGE of plasma from three patients undergoing fluorescein angiography with nonradioactive dye showed the only fluorescent band migrating ahead of all protein bands. These methods failed to demonstrate specific binding of tritiated fluorescein to normal human plasma proteins. We conclude that during angiography, fluorescein exists in plasma as an unbound molecule or is so weakly associated with plasma proteins as to be undetectable by the methods used.

Blood Proteins↗
PubMed1989

The use of fluorescein-conjugated lectins for visualizing atypical mycobacteria.

We investigated the feasibility of using fluorescein-conjugated lectins for visualizing and differentiating two species of atypical mycobacteria. Pure cultures of Mycobacterium fortuitum and Mycobacterium chelonei were established, as was an experimental model of infectious keratitis involving these two organisms. Samples from the pure cultures and corneal scrapings were placed on glass slides, fixed, and incubated with one of a panel of 22 fluorescein-conjugated lectins. The slides were examined using an epifluorescence microscope. Fluorescein-conjugated concanavalin A brightly stained both species of atypical mycobacteria, in both the pure culture and experimental keratitis samples. Several additional fluorescein-conjugated lectins (wheat germ agglutinin, succinylated wheat germ agglutinin, Phaseolus vulgaris erythroagglutinin, and Psophocarpus tetragonolobus agglutinin) brightly stained M chelonei, but only moderately stained M fortuitum. These staining patterns are consistent with the known carbohydrate compositions of the cell walls of atypical mycobacteria and suggest that fluorescein-conjugated lectins may be useful for the visualization of these organisms in corneal infections.

Abscess↗
PubMed1993

Microscopic visualization of the retina by angiography with high-molecular-weight fluorescein-labeled dextrans in the mouse.

Methods currently available for the examination of the retinal vasculature of laboratory animals have significant drawbacks. Fluorescein angiography of rodent eyes is hampered by a poor view of the peripheral retina and difficulty in performing fundus photography. Methods of staining or filling retinal vessels are unreliable, labor-intensive, or have high backgrounds. We have developed a novel technique that is quick, simple, and accurate. Fluorescein-labeled 2 million molecular weight dextrans are used to fill the retinal vasculature of mice in vivo, followed by removal of the retina, fixation in paraformaldehyde, and examination of the vascular pattern in whole mount preparations by fluorescence microscopy. We found that fluorescein and fluorescein-labeled low-molecular-weight dextrans (40,000-500,000) are not suitable as they leak out of the vasculature to stain the entire retina in whole mount preparations. By contrast, fluorescein-labeled 2 million molecular weight dextrans remain in the vasculature for many months without diffusion or decay. Under low magnification, the entire retinal vasculature can be visualized at one time. By focusing from one plane to another, the superficial, connecting, or deep vascular layers are delineated. The background fluorescence is very low. We have successfully used this technique in over 20 mice per day to document retinal angiogenesis in a model of oxygen-induced proliferative retinopathy.

Animals↗
PubMed1992

Estimation of irrigant absorption during transurethral resection of the prostate. Assessment of fluorescein as a marker.

Absorption of irrigating solution may complicate transurethral resection of the prostate (TURP), and a system which warns of fluid overload reliably would be of benefit in the prevention of these complications. Fluorescein can easily be detected at very low concentrations in blood and can be added to the irrigating solution in amounts invisible to the naked eye, providing a possible means of easily monitoring the absorption of irrigant solution during TURP. To test this hypothesis, the plasma concentration of fluorescein was determined at intervals after intraperitoneal injection in rats. Although the published data on fluorescein suggest that it meets the criteria for a suitable marker substance to be introduced into the irrigant solution, the results show that plasma fluorescein is constant and not dose related. The addition of fluorescein to the irrigant solution would not provide a quantitative means of determining the volume of irrigant absorbed. The use of other substances may provide the answer to this major clinical problem. We have defined a set of criteria which such a substance should fulfil.

Absorption↗
PubMed1995

Evaluation of the range of areas of the fluorescein staining patterns of the tarsal conjunctiva in man.

Fluorescein dye is commonly used to highlight the tarsal conjunctiva in man to facilitate diagnosis of papillary conjunctivitis. A quantitative analysis of the fluorescein-highlighted features could be useful in both assignment of severity grades as well as for objective comparisons but no data is available on the distributions of sizes (areas) of these features. An exploratory, range-finding study was undertaken to provide data on feature areas that might be encountered. After application of fluorescein, 35 mm photographs were taken at a fixed distance with zone 1/zone 2 (Allansmith) of the tarsal plate aligned perpendicular to the camera. The photographs were projected, an overlay of 150 to 180 contiguous features outlined by fluorescein made and planimetry used to assess the areas and area distributions of the features on tarsal plates clinically graded with stages 1 to 4 papillary hypertrophy. For zone 1 of the tarsal plate in asymptomatic subjects, a fluorescein solution highlights the limits of features that enclose an area averaging 30,000 microns2 (range 8000 to 120,000; median area of close to 35,000 microns2). The areas of these features were generally normally distributed and there was little variation in feature areas across the zone. At different stages of clinical papillary conjunctivitis, the areas of the negative staining patterns are larger. Averages of 60,000 to 90,000 microns2, median values of close to 70,000 microns2 and individual feature areas up to 350,000 microns2 were seen in mildly symptomatic patients. These distributions were generally heterogeneous and showed a skewed distribution. Areas averaging up to 0.755 mm2 (range 0.6 to 3.2 mm2) were measured in moderate to severe papillary hypertrophy.

Cell Count↗
PubMed1992

The role of intravenous fluorescein in the detection of colon ischemia during aortic reconstruction.

Intravenous fluorescein is an accurate predictor of small bowel viability, but its effectiveness in assessing colon perfusion during aortic surgery has not been evaluated. Over a 10 year period 186 of 3,306 patients undergoing aortic reconstruction received 500 to 1000 mg of intravenous fluorescein intraoperatively to evaluate colon viability. Prior history of colectomy, hypogastric or mesenteric arterial occlusive disease, or ruptured aneurysm placed these patients at risk to develop ischemic colitis. Patients were operated on for aneurysmal disease (n = 94), occlusive disease (n = 66), or a combination of both (n = 26): 171 exhibited uniform normal perfusion patterns under Wood's lamp illumination, while in 11 it was "patchy." None of these patients developed full-thickness ischemic colitis (observed specificity: 100%). Fluorescence of the rectosigmoid was absent in four patients. One of these patients with a ruptured aneurysm underwent immediate sigmoid resection, while three underwent inferior mesenteric artery reimplantation. The fluorescein pattern subsequently normalized in two patients, but one underwent sigmoid resection for an expanding mesenteric hematoma. The second patient recovered without complications. The final patient continued to show a segmental sigmoid defect and postoperatively developed full-thickness injury requiring sigmoidectomy. During the same period 18 other patients developed transmural colon ischemia from 3,120 aortic reconstructions (0.6%), with a mortality rate of 56%. None had received intraoperative fluorescein. Selective use of intravenous fluorescein may reduce the mortality of ischemic colitis following aortic reconstruction.

Aorta, Abdominal↗