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 163 records · Page 9Linked to original sources
PubMed1991

Is the fluorescein dilaurate test suitable for monitoring the effectiveness of pancreatic enzyme replacement therapy?

We have employed an oral test of pancreatic digestive function using fluorescein dilaurate (a substrate for pancreatic cholesterol ester hydrolase), administered together with pancreatic enzyme supplements, in order to test the hypothesis that urinary excretion of fluorescein provides a simple method for determining the optimal dose of oral pancreatic enzymes. Commercially available pancreatic enzyme supplements had negligible cholesterol hydrolase activity in vitro, and did not increase the urinary excretion of fluorescein when administered together with fluorescein dilaurate in 16 patients with pancreatic exocrine insufficiency. Inhibition of gastric secretion by ranitidine resulted in a statistically significant increase in urinary fluorescein excretion during the fluorescein dilaurate test. The fluorescein dilaurate test is not, therefore, suitable for determining the effectiveness of oral pancreatic enzyme replacement therapy. Moreover, the manufacturer's advice to stop oral pancreatic enzyme therapy for 5 days before performing the fluorescein dilaurate test appears unnecessary, since oral pancreatic enzymes do not alter test results.

Amylases↗
PubMed2004

The correlation between fluorescein angiographic and optical coherence tomographic features in clinically significant diabetic macular edema.

PURPOSE: To assess the correlation between the features of optical coherence tomography (OCT) and fluorescein angiography in clinically significant diabetic macular edema. DESIGN: Retrospective observational case series. METHODS: This study involved 145 eyes (91 patients) with clinically significant diabetic macular edema. The fluorescein angiography features were categorized into focal leakage type, diffuse leakage type, and diffuse cystoid leakage type. The OCT features were categorized into four types: type 1, thickening with homogeneous optical reflectivity; type 2, thickening with markedly decreased optical reflectivity in the outer retinal layer; type 3A, foveolar detachment without traction; and type 3B, foveolar detachment with apparent vitreofoveal traction. The correlation between fluorescein angiography types and OCT types were analyzed, and their associations with visual acuity, central foveal thickness. and stages of diabetic retinopathy were evaluated. RESULTS: The prevalence of OCT type 1 was higher in the focal leakage type (73.0%) and in the diffuse leakage type (58.9%) than in the diffuse cystoid leakage type (3.8%) of fluorescein angiography (P <.0001). The prevalence of OCT type 2 and 3A was higher in the diffuse cystoid leakage type (57.7% and 34.6%, respectively) than in the focal leakage type (20.6% and 3.2%) or diffuse leakage type(28.6% and 10.7%; P <.0001). The stages of retinopathy correlated with fluorescein angiography types (P =.016). Optical coherence tomography type 1 and the focal leakage type of fluorescein angiography showed the least foveal thickness and the best visual acuity (P <.05). CONCLUSIONS: There was a significant correlation between the features of OCT and fluorescein angiography in clinically significant diabetic macular edema. The combined data from both OCT and fluorescein angiography may provide a clearer understanding of the anatomic and physiologic characteristics of clinically significant diabetic macular edema.

Adult↗
PubMed2006

Optimization of anterior eye fluorescein viewing.

PURPOSE: To optimize anterior eye fluorescein viewing and image capture. DESIGN: Prospective experimental investigation. METHODS: The spectral radiance of ten different models of slit-lamp blue luminance and the spectral transmission of three barrier filters were measured. Optimal clinical instillation of fluorescein was evaluated by a comparison of four different instillation methods of fluorescein into 10 subjects. Two methods used a floret, and two used minims of different concentration. The resulting fluorescence was evaluated for quenching effects and efficiency over time. RESULTS: Spectral radiance of the blue illumination typically had an average peak at 460 nm. Comparison between three slit-lamps of the same model showed a similar spectral radiance distribution. Of the slit-lamps examined, 8.3% to 50.6% of the illumination output was optimized for >80% fluorescein excitation, and 1.2% to 23.5% of the illumination overlapped with that emitted by the fluorophore. The barrier filters had an average cut-off at 510 to 520 nm. Quenching was observed for all methods of fluorescein instillation. The moistened floret and the 1% minim reached a useful level of fluorescence in on average approximately 20s ( approximately 2.5x faster than the saturated floret and 2% minim) and this lasted for approximately 160 seconds. CONCLUSIONS: Most slit-lamps' blue light and yellow barrier filters are not optimal for fluorescein viewing and capture. Instillation of fluorescein using a moistened floret or 1% minim seems most clinically appropriate as lower quantities and concentrations of fluorescein improve the efficiency of clinical examination.

Adult↗
PubMed1995

Topographical evaluation of skin perfusion patterns in peripheral arterial occlusive disease by means of computer-assisted fluorescein perfusography.

OBJECTIVE: To evaluate the clinical impact of computer-assisted fluorescein perfusography in peripheral arterial occlusive disease (PAOD). DESIGN: Foot and calf skin perfusion was visualised by intravenous fluorescein injection. Fluorescein influx was recorded photographically and converted into functional images of fluorescein appearance times (AT) by means of digital film processing. SETTING: Vascular Laboratory of Clinic for Vascular Disease. MATERIALS: 249 patients with PAOD. Among 481 limbs studied, 83 legs presented with patent arteries, 70 with asymptomatic obstructions (Stage I), 170 with claudication (Stage II) and 158 with rest pain and skin lesions (Stage III/IV). CHIEF OUTCOME MEASURES: Forefoot and calf mean ATs and standard deviations (SD) served as arbitrary measures of regional skin perfusion rates and their homogeneity, respectively. MAIN RESULTS: In the control legs, a homogeneous and fast fluorescence appearance was observed (medians at the foot: AT33.4 s, SD 3.6). In stage II disease, AT (39.9 s, SD 5.6) were slightly impaired as compared to limbs with patent arteries or stage I disease (p < 0.01). Ninety-seven out of the 158 legs in stage III/IV could be managed by conservative therapy. According to fluorescein-perfusography, they did not differ from stage II disease (AT 38.8 s, SD 6.1). Sixty-one limbs were clinically affected by critical ischaemia. They exhibited a markedly delayed and heterogenous fluorescein influx at the foot (AT 77.3 s, SD 26.5, p < 0.01 vs all other groups). Non-fluorescent areas occurred in 53% compared to only 1% of limbs with and without critical ischaemia, respectively. Retrospectively, predictive values of fluorescein perfusography in identifying a critical limb ischaemia (accuracy 93%) were superior to the ankle systolic arterial pressure determination (accuracy 80%). CONCLUSIONS: Fluorescein perfusography seems to be of diagnostic and prognostic use in PAOD in stage III/IV where inflammatory and ischaemic patterns of dye appearance can be distinguished.

Adult↗
PubMed2002

Fluorescein transit test time and symptomatic outcomes after external dacryocystorhinostomy.

PURPOSE: To determine the relation between the fluorescein transit test time and postoperative relief of epiphora in patent dacryocystorhinostomies. METHODS: A retrospective study of 40 patients who underwent 42 external dacryocystorhinostomies between January 1994 and January 2000 was performed. Postoperative symptomatic success was assessed by a questionnaire. Intranasal rigid endoscopy was performed to measure the fluorescein transit test time, defined as the time from instillation of fluorescein to its free flow from the osteotomy site. The main outcome measures were symptomatic success, fluorescein transit test time, and anatomic patency to irrigation. Statistical analysis was performed with the use of the Fisher exact test. RESULTS: Of the 42 dacryocystorhinostomies studied, 92.8% were patent to irrigation. There was a statistically significant association between a fluorescein transit test time of < or = 45 seconds and subjective success (P<0.001), with 96% of patients reporting a successful postoperative outcome. A slow fluorescein transit test, with an average time of 138.9 seconds, was associated with symptomatic failure (P<0.001), with 56.2% of this group reporting significant postoperative epiphora. CONCLUSIONS: The fluorescein transit test provides a quantitative measure of lacrimal drainage function after dacryocystorhinostomy, with a fluorescein transit test time of < or = 45 seconds being the relevant parameter to characterize symptomatic success. Postoperative failure in external dacryocystorhinostomy, as evidenced by slow transit times, may result from surgical interference with the lacrimal pump.

Adult↗
PubMed2001

A comparison of two methods of evaluating cornea-to-contact lens base curve fluorescein patterns in keratoconus.

PURPOSE: The purposes of the study were as follows: (1) to compare the apical fitting relationship of habitual contact lens fluorescein patterns in keratoconus as determined by clinician assessment of on-eye patterns to those determined by photograph readers looking at slides of fluorescein patterns and (2) to determine the validity of the techniques used in assessing the apical fitting relationships of rigid corneal contact lenses on keratoconic corneas. METHODS: Central fluorescein patterns of rigid contact lens-wearing keratoconus patients enrolled in the Collaborative Longitudinal Evaluation of Keratoconus (CLEK) Study were graded as "definite touch," "touch," "clearance," or "definite clearance" by certified clinicians. Photographs of these patterns were evaluated independently by certified, masked photograph readers using the same grading scale. RESULTS: Agreement between "re-reads" of the same fluorescein pattern slides by the photograph readers was substantial (weighted kappa = 0.751). Agreement between assessments of habitual fit fluorescein patterns at the baseline vs. the repeat visits was poor for the photograph readers (weighted kappa = 0.254) and moderate for the clinicians (kappa = 0.480). Agreement between clinicians' and photograph readers' assessment of the habitual contact lens fluorescein pattern at the baseline visit was fair (weighted kappa = 0.382). CONCLUSIONS: Repeatability and validity of this technique were fair to excellent. Many factors influence fluorescein pattern interpretation, and improvement of the objective method of fluorescein pattern assessment by photograph readers will require improved methodology that takes these factors into consideration.

Contact Lenses↗
PubMed2006

Topical intranasal fluorescein: the missing partner in algorithms of cerebrospinal fluid fistula detection.

OBJECTIVE: The aim of this work was to focus on the development and validation of the use of topical fluorescein in the intraoperative localization of cerebrospinal fluid (CSF) fistulas, and to screen its use in preoperative diagnosis of CSF rhinorrhea as well as postoperative detection of a recurrence. MATERIALS AND METHODS: Twenty-five patients with CSF rhinorrhea were treated with an endoscopic endonasal technique. Topical intranasal 5% fluorescein was used for preoperative diagnosis and intraoperative localization of the site of the leak. A change in the color of the fluorescein from yellow to green fluorescence and sometimes streaming the fluorescein over the nasal mucosa and blood denoted the presence of CSF, and the site of the leak could be traced. RESULTS: The cause of the leak was accidental trauma in 11 patients, spontaneous in 9 patients, and iatrogenic in 5 patients. The ethmoidal roof was the most common site of leak (52%) followed by the cribriform plate (40%) and then the sphenoid sinus (8%). We have achieved 100% success rate in sealing the CSF fistulas in our 25 patients with no recurrence detected during the follow-up period (mean, 19+/-10 months). The preoperative use of fluorescein-soaked cotton pledgets was 100% accurate in diagnosing CSF rhinorrhea when compared with B2 transferrin testing. The intraoperative use of topical intranasal fluorescein was also 100% accurate in locating the site of the CSF fistula when compared with the surgical findings. No major complications have been reported. CONCLUSION: In the presence of a clinically diagnosed CSF leakage, topical fluorescein is a very easy, sensitive, safe, and highly accurate tool in the intraoperative localization of the site and extent of CSF fistulas, and should be considered a viable noninvasive alternative to intrathecal fluorescein. We also recommend its use as a simple and quick outpatient clinic test for preoperative diagnosis of CSF rhinorrhea. It can be used postoperatively as well when there is a doubt of recurrence of the CSF leak.

Administration, Intranasal↗
PubMed1999

Effects of acetazolamide on passive and active transport of fluorescein across the normal BRB.

PURPOSE: To investigate the effect of the carbonic anhydrase inhibitor acetazolamide (AZM) on passive permeability and active transport of fluorescein across the blood-retina barrier in healthy subjects. The study may have implications for the understanding of the edema-reducing effect of AZM. METHODS: The effect of AZM on the blood-retina barrier function was assessed by differential vitreous spectrofluorometry using fluorescein as a tracer. The study included fourteen healthy subjects in a randomized double-masked crossover trial with 3 days' treatment with AZM (500 mg/d) and placebo, respectively. The two examinations were separated by at least 1 week. Fluorescein concentration was determined separately from its metabolite fluorescein glucuronide. The passive permeability of fluorescein was determined by computerized modeling and curve-fitting to the preretinal curve and the plasma concentration curve obtained at 30 to 60 minutes after the injection of fluorescein. The unidirectional permeability due to outward active transport from vitreous to blood was estimated from the preretinal gradient and the plasma concentration at 7 to 10 hours after injection. RESULTS: Treatment with AZM was associated with significant increases in passive permeability and unidirectional permeability of fluorescein. For the passive permeability the increase was on average 0.3+/-0.4 nm/s (mean+/-SD; range, -0.8-1.0 nm/s), and for the unidirectional permeability the increase was on average 7.4 nm/s+/-7.0 (mean+/-SD; range, -3.3-19.0 nm/s). CONCLUSIONS: Acetazolamide caused an increase in passive permeability. Unidirectional permeability was increased by AZM, indicating a stimulation of the outward active transport of fluorescein. It has been proposed that the edema-reducing effect of AZM is due to stimulated ion and fluid removal from the retina to the choroid. The results of this study are consistent with AZM affecting the blood-retina barrier with stimulation of at least one ion transport mechanism.

Acetazolamide↗
PubMed1981

[Diagnosis of pancreatic function. Simplified screening with fluorescein dilaurate using serum concentration determinations].

Fluorescein-dilaurate has been recommended as a screening test for the assessment of exocrine pancreatic function. In this test fluorescein excretion in the urine is measured for an 8--10 hour period. To avoid urine collection the present study reports on serum fluorescein determinations following oral administration of fluorescein-dilaurate-ester. According to the results of a standard secretin-pancreozymin-test 24 subjects were classified as 10 persons with normal pancreatic function, 7 patients with mild and 7 patients with severe exocrine pancreatic insufficiency. Fluorescein concentrations were measured photometrically after TCA-precipitation. In the normal persons maximal fluorescein levels were observed 4--6 hours after oral load of the test substance. Patients with mild pancreatic insufficiency showed the same pattern and only in patients with severe pancreatic insufficiency much lower serum fluorescein concentrations were found. They were statistically significantly different from normal subjects 3--6 hours after administration of fluorescein-dilaurate.

Adult↗
PubMed1977

[Kinetic analysis of mechanisms of Na+-dependent organic acid transport in the proximal tubules of surviving frog kidney. II. Relationship between Na+ concentration in the medium and changes in the parameters of the Michaelis-Menten equation for fluorescein and uranin transport].

The dependence of active transport rates of fluorescein and uranin into proximal tubules was studied, firstly, on the concentration of these substrates in the incubation medium with constant Na-concentration and, secondly, on Na+-concentration in the medium with constant concentrations of fluorescein or uranin, Km, Vmax, and KmNa, VmaxNa values being determined correspondingly. With the decrease of Na+-concentration in the medium the apparent Km values for fluorescein and uranin increase, while Vmax values remain unchanged and ratios Vmax/Km decrease. The 1/Km value for uranin transport is a linear function of Na+-concentration, while it is a quadratic function of Na+-concentration for fluorescein transport. The KmNa value for fluorescein transport is twice as much as that for uranin transport. The obtained data suggest that one Na+-ion is spent from the medium for translocation of one uranin molecule across the basal membrane, whereas two Na+-ions from the medium are necessary for translocation of one fluorescein molecule. It is assumed that fluorescein and uranin transports are carried out by producing a four-fold transporting complex (a carrier+a substratum+2Na+; in the case of fluorescein 2Na+ appear from the medium, whereas in the case of uranin only one Na+ from the medium is used.

Animals↗
PubMedDate not supplied

Shear rate and hematocrit dependence of fluorescence from retinal vessels in fluorescein angiography.

The purpose of this work was to obtain more quantitative knowledge about the yield of fluorescence from retinal vessels during fluorescein angiography. The influence of shear rate, concentration of sodium fluorescein, hematocrit, and layer thickness on the yield of fluorescence from blood were investigated. Measurements were performed in vitro on samples of human blood in a cone-plate shear chamber using frontal illumination. Application of physiologically relevant levels of shear (> 88/sec) decreased the yield of fluorescence from the blood sample considerably as compared with stasis. The yield of fluorescence was proportionally related to the logarithm of the sodium fluorescein concentration in blood up to a sodium fluorescein concentration of 1.2 mg/ml. Above that concentration quenching occurred. An increase in layer thickness at a hematocrit of 45% resulted only in an increase of the yield of fluorescence up to a layer thickness of 25 microns. In conclusion, the sodium fluorescein concentration in blood is the only important factor that determines the yield of fluorescence from the larger retinal vessels in the successive phases of the fluorescein angiogram in a subject with a given hematocrit and hemoglobin concentration. The yield of fluorescence from retinal vessels (> 25 microns) is proportionally related to the logarithm of the sodium fluorescein concentration over a broad range of concentrations.

Biophysical Phenomena↗
PubMed1989

[Fluorescence photometry study of the normal rat retina before and following fluorescein administration].

Semiquantitative fluorescein photometric studies were performed on the retinas of lyophilized rat eyes. Before injecting the fluorescein, the right, dyeless eyes were enucleated under anesthesia with ketamine hydrochloride. The left eyes were removed between 20 seconds and two hours after intravenous injection of fluorescein. Histologic sections of each of the posterior segments were measured fluorophotometrically. The photometric values of most of the fluorescein-dyed retinal sections were higher than those of the contralateral (dyeless) control eyes. With increasing duration of observation the differences between the sections which contained fluorescein and those which did not diminished, although some temporary and limited increases occurred. The higher extinction values of the specimens containing fluorescein are in agreement with the quantitative results of Grimes et al. (1982), who found fluorescein in all retinal layers. Anesthesia-induced acidoses cannot be ruled out may be considered minimal. The information value of quantitative and semiquantative results is certainly superior to qualitative results is certainly superior to qualitative findings.

Animals↗
PubMedDate not supplied

Fluorescein angiography--is it safe to use in a pregnant patient?

We sent questionnaires to 424 retina specialists in order to compile information on the use of fluorescein angiography in pregnant women. Four-hundred and three specialists responded. Of these, 313 (78%) had never performed fluorescein angiography on a pregnant woman. Ninety specialists (22%) had performed at least one fluorescein angiogram on a pregnant woman; detailed information was obtained on 105 patients. Authors of previous reports that included fluorescein angiography during pregnancy provided information on an additional 11 patients. Substantiated side effects were nausea and/or vomiting in seven patients. Anomalies at birth, an undescended testicle and syndactyly, were reported in two children. There was one stillbirth with pathologic findings classic for toxemia and one fetal death not related in time to fluorescein angiography. One therapeutic abortion was performed for complications in toxemia. One spontaneous abortion occurred 3 days after fluorescein angiography in a patient who was four weeks pregnant. Eight children born to toxemic mothers had low birth weights. Based on our data, we conclude that fluorescein angiography does not offer a high rate of birth anomalies or complications during pregnancy.

Adult↗
PubMed1991

A new fluorescent probe for the equilibrative inhibitor-sensitive nucleoside transporter. 5'-S-(2-aminoethyl)-N6-(4-nitrobenzyl)-5'-thioadenosine (SAENTA)-chi 2-fluorescein.

The N6-(4-nitrobenzyl) derivative of adenosine is a tight-binding inhibitor of the equilibrative inhibitor-sensitive nucleoside transporter of mammalian cells. A fluorescent ligand for this transporter has been synthesized by allowing an adenosine analogue. 5'-S-(2-aminoethyl)-N6-(4-nitrobenzyl)-5'-thioadenosine (SAENTA), to react with fluorescein isothiocyanate. The purified adduct had a SAENTA/fluorescein molar ratio of 0.92:1 calculated from its absorption spectrum. The intensity of fluorescent emission from the SAENTA-chi 2-fluorescein adduct was 30% that of fluorescein isothiocyanate (chi 2 is the number of atoms in the linkage between fluorescein and SAENTA). SAENTA-chi 2-fluorescein inhibited the influx of nucleosides into cultured leukaemic cells with an IC50 (total concentration of inhibitor producing 50% inhibition) of 40 nM. The adduct inhibited the binding of [3H]nitrobenzylthioinosine ([3H]NBMPR) with half-maximal inhibition at 50-100 nM. Mass Law analysis of the competitive-binding data suggested the presence of two classes of sites for [3H]NBMPR binding, only one of which was accessible to SAENTA-chi 2-fluorescein. Flow cytometry was used to analyse equilibrium binding of SAENTA-chi 2-fluorescein to leukaemic cells and a Kd of 6 nM was obtained. SAENTA-chi 2-fluorescein is a high-affinity ligand for the equilibrative inhibitor-sensitive nucleoside transporter which allows rapid assessment of transport capacity by flow cytometry.

Adenosine↗
PubMed1998

Simultaneous indocyanine green and fluorescein angiography using a confocal scanning laser ophthalmoscope.

BACKGROUND: Fluorescein and indocyanine green (ICG) angiography are both useful in the diagnosis and treatment of many retinal diseases. In some cases, both tests must be performed for diagnosis and treatment; however, performing both is time-consuming and may require multiple injections. METHODS: We designed a compact digital confocal scanning laser ophthalmoscope to perform true simultaneous fluorescein and ICG angiography. We report our experience using the instrument to perform 169 angiograms in 117 patients. RESULTS: There were no unexpected adverse effects from mixing the dyes and administering them in 1 injection. An entire examination, including fundus photography, fluorescein angiography, and ICG angiography, could be performed in 45 minutes. It was possible to study differences in fluorescein patterns by comparing identically timed frames and to find cases in which ICG or fluorescein was optimal in visualizing retinal and subretinal structures. Confocal optical sections in the depth (z) dimension allowed viewing in different planes. It was possible to overlay ICG and fluorescein images or compare them side-by-side using a linked cursor. Digital transmission of the images was also performed. CONCLUSIONS: Simultaneous ICG and fluorescein angiography can be performed rapidly, safely, and conveniently. The availability of simultaneous angiography will allow critical determination of the relative advantages and disadvantages of both types of angiography.

Choroid↗
PubMed2000

Angiography of fluoresceinated anti-vascular endothelial growth factor antibody and dextrans in experimental choroidal neovascularization.

OBJECTIVE: To determine if anti-vascular endothelial growth factor antibody and a range of dextrans with varying diffusion radii and molecular weights are permeable through experimental choroidal neovascularization (CNV). METHODS: Choroidal neovascularization was induced in 10 cynomolgus monkey retinas by means of argon laser injury. Digital fundus fluorescein angiograms were performed with fluorescein sodium, fluoresceinated IgG antibodies (anti-vascular endothelial growth factor and a control antibody), and fluoresceinated dextrans with molecular weights of 4, 20, 40, 70 and 150 kd. The 40- and 70-kd dextrans straddle the effective diffusion radius of IgG. For each reagent, early and late angiograms were performed in a standardized fashion, with follow-up images obtained to monitor residual fluorescence. RESULTS: Perfusion of retinal vessels and choroidal vasculature was seen with all reagents. Fluorescein and 4- and 20-kd dextran leaked rapidly from the CNV within the first minute. Angiography with the use of 40-kd dextran and fluoresceinated antibody, either anti-vascular endothelial growth factor or control IgG, showed fluorescence within the CNV that increased during the first 1 to 5 hours, with mild leakage from the CNV. By 24 hours, fluorescence in the CNV was minimal, although in some cases persistent fluorescence in the surrounding tissue was evident up to 2 weeks. The 70-kd dextran showed fluorescence within the CNV and leakage in 1 of 3 eyes. The 150-kd dextran showed fluorescence within the CNV but did not demonstrate leakage. CONCLUSIONS: Fluoresceinated antibodies and dextran with smaller effective diffusion radii showed CNV perfusion and leakage. Dextrans with larger effective diffusion radii (70 kd and 150 kd) perfused into CNV but did not show leakage consistently. CLINICAL RELEVANCE: Determining the permeablity of antibodies and molecules of similar size through CNV can help ascertain the feasibility of using intravenously administered antibodies against angiogenic growth factors as a future treatment for choroidal neovascularization.

Animals↗
PubMed1983

Outward transport of fluorescein from the vitreous in normal human subjects.

The permeability of the blood-vitreous barrier to fluorescein passing out of the vitreous does not necessarily equal the permeability to fluorescein passing into it. We calculated the ratio between the outward and inward permeability coefficients of the blood-vitreous barrier in eight normal men who ingested 3-g of sodium fluorescein. The calculation was based on the ratio between the serum free fluorescein and the vitreous fluorescein concentrations (as determined by fluorophotometry) when the net transport across the barrier was zero. The outward permeability to fluorescein was 31 +/- 18 times (mean +/- SD) the inward permeability. To our knowledge, this article provides the first direct evidence for a specialized transport mechanism in humans whereby fluorescein is removed from the vitreous into the blood. The malfunction of this process may be important in human diseases. Pharmacologic manipulation of this process may be possible.

Adult↗
PubMed1987

Angiography with fluorescein-labeled dextrans in a primate model of uveitis.

Sequential fluorescein angiography, using fluorescein-labeled dextran molecules of several different sizes, was carried out in monkeys with intraocular inflammation induced with interphotoreceptor retinoid-binding protein. The vascular leakage seen with the dextrans was compared with that seen with standard fluorescein sodium angiography. The angiograms demonstrated that different-sized leaks appear in the retinal vessels in adjacent areas during the course of the inflammation. Most retinal vessels leaked only fluorescein sodium and no dextran of any size, suggesting that it is the unbound fluorescein that leaks out of these vessels and not fluorescein bound to plasma albumin. It was not possible to tell by clinical examination which areas would leak the larger-molecular weight tracers. Ultrastructural studies of the veins leaking the dextrans revealed areas of abnormal endothelial tight junctions, whereas the tight junctions were normal in areas where leakage occurred with fluorescein alone.

Animals↗