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PubMed2005

High resolution imaging of fluorescein patterns in RCS rat retinae and their direct correlation with histology.

To assess the progressive changes in the retinal vascular bed of dystrophic and non-dystrophic Royal College of Surgeons (RCS) rats, retinae, were visualised correlating in vivo fundus fluorescein angiography (FA) with histology. FA was performed in rats aged 5 weeks to 2 years, using a Zeiss confocal scanning laser ophthalmoscope (cSLO). After the final imaging session, a subset of retinae were prepared for flat-mount histology and the vascular bed was visualised using nicotinamide adenine dinucleotide phosphate-diaphorase (NADPH-d) staining. While non-dystrophic rat retinae showed no substantive changes in vascular patterns with age and no demonstrable fluorescein leakage up to at least 1 year, dystrophic rat retinae showed abnormal vascular formations, demonstrable on FA and NADPH-d staining, which could be correlated in single retinae. Hyperfluorescent spots and late angiographic leakage were evident beginning at 10 weeks and progressed in severity with time: they were coincident in distribution with abnormal histological vascular complexes. The ability to monitor the same retina serially makes this approach a valuable tool for studying the dynamics of vascular change in the diseased retina, not only during the course of degeneration but also when assessing efficacy of potential therapeutic approaches.

Animals↗
PubMed2004

Fluorescein angiographic lesion type frequency in neovascular age-related macular degeneration.

OBJECTIVE: To assess the frequency of lesion types using fluorescein angiography (FA) in neovascular age-related macular degeneration (nAMD). DESIGN: Cross-sectional study. PARTICIPANTS: Two hundred cases of nAMD. METHODS: Fluorescein angiograms from 908 patients (university-based, tertiary retinal referral practice [UP] = 478; comprehensive, community-based eye clinic [CC] = 430) were reviewed to identify 200 cases of nAMD (100 from each center). Two graders evaluated the frequency of angiographic subtypes. MAIN OUTCOME MEASURES: Identifying (1) the frequency of subfoveal nAMD lesions that meet the definition of "predominantly classic," "minimally classic," "occult with no classic"; (2) lesion location, size, and subtype; and (3) the intergrader agreement (kappa). RESULTS: There was little difference in the frequency of lesion type between the UP and the CC. Most nAMD lesions were subfoveal (78.5%, 157 of 200), and of these, 20% (32 of 157) were predominantly classic; whereas 73% (114 of 157) were occult with no classic, and 7% (11 of 157) were minimally classic. Of the 200 angiograms, 33 (16.5%) were juxtafoveal, and 10 (5%) were extrafoveal. Twenty of the 43 juxtafoveal and extrafoveal lesions (47%) were predominantly classic. Classic with no occult subfoveal lesions were smaller than minimally classic or occult with no classic (1.7 vs. 3.7 and 2.8 mm; P = 0.001 and 0.01, respectively). Of 114 subfoveal occult with no classic lesions, 54 (47%) had both smaller lesion size <==4 disc areas (DA) and lower visual acuity <20/50, whereas 107 (94%) had a smaller lesion or lower visual acuity. CONCLUSIONS: Most angiographic lesions of patients who undergo FA for nAMD are subfoveal and occult. We estimate that 20% of subfoveal lesions are predominantly classic. Approximately half of the juxtafoveal and extrafoveal lesions are predominantly classic. Nearly 30% of all nAMD lesions have both small occult lesions (size <==4 DA) and a visual acuity less than 20/50. We found minimal difference in lesion type between a UP and a CC.

Aged↗
PubMed1994

Fluorescein angiography in acute nonarteritic anterior ischemic optic neuropathy.

Fundus fluorescein angiograms from 41 patients with nonarteritic anterior ischemic optic neuropathy of less than three weeks' duration were compared with those from 43 age-matched control subjects. Patients with disease showed statistically significant delay in both the onset and the time to completion of prelaminar optic disk filling. Neither onset nor completion of peripapillary choroidal filling were markedly delayed when compared with control subjects. Frequency of occurrence of delayed filling within peripapillary choroidal watershed zones was not increased in patients with disease. There was no consistent correlation by quadrant between optic disk filling delay, choroidal filling delay, optic disk swelling or hyperfluorescence, and visual field deficit. No trend for change in characteristics was found with increasing time interval from onset of symptoms to performance of angiography. Fluorescein angiography in nonarteritic anterior ischemic optic neuropathy demonstrates delayed optic disk filling without consistent relation to adjacent peripapillary choroidal filling delay or other disease findings.

Acute Disease↗
PubMed1985

Fluorescein angiography in reticular degeneration of the pigment epithelium.

We studied reticular degeneration of the pigment epithelium by fluorescein angiography in 32 eyes of 50 consecutive patients who had ophthalmoscopic indications of this aging-related entity. In this type of degeneration, fluorescein angiography delineated extensive abnormalities of the retinal pigment epithelium and demonstrated normal-appearing retinal vessels and choriocapillaries in the affected areas.

Aged↗
PubMed1977

Flow cytometric measurement of the polarization of fluorescence from intracellular fluorescein in mammalian cells.

Based on the description of a laboratory-built flow cytometer, the necessary modifications of this instrument for the measurement of fluorescence polarization are described. At a maximum rate exceeding 1,000 cells/s, the instrument is capable of measuring simultaneously the horizontally and vertically polarized component of the fluorescence emitted from stained cells excited with vertically polarized light. By mathematical analysis of the accumulated data, the distribution of polarization values in the population is obtained. Various sources of instrumental error have been investigated. The large aperture of the detector optics leads to systematic underestimation of the polarization values. Other errors are negligible, and the instrument is shown to give results consistent with the theory of fluorescence polarization. Application of the instrument is illustrated by experiments with mammalian cells exposed to the fluorogenic substrate fluorescein diacetate (FDA). The polarization of the fluorescence from intracellular fluorescein produced by hydrolysis of FDA is measured, giving information on the cytoplasmic microviscosity. It appears that this microviscosity is constant over the cell cycle. On the other hand, it is significantly affected by the osmolarity of the medium.

Cell Division↗
PubMed1978

Fluorescein excitation and emission polarization spectra in living cells: changes during the cell cycle.

Changes in the fluorescein fluorescence emission and excitation polarization spectra in synchronized cultured S3 fibroblasts at G1, mid-S, and mitosis, as well as in human lymphocytes before and after stimulation with mitogens, were studied. In contrast to those measured in aqueous solutions the emission and excitation polarization spectra in living cells exhibit a wavelength dependence characteristic for the state of the cell cycle. Changes in the temperature and in the amount of intracellular water result in quantitative wavelength-independent changes in the polarization spectra. Possible mechanisms for the qualitative wavelength-dependent changes in the fluorescein emission and excitation polarization spectra during the cell cycle are discussed.

Cell Cycle↗
PubMed1979

Involvement of mitochondria in changes in fluorescein excitation and emission polarization spectra in living cells.

The comparison of fluorescein polarization spectra in living cells and in isolated subcellular structures identified the mitochondria as the cytoplasmic domain in which on excitation at 470 nm the sharp fluorescein emission polarization peak at 510 nm is formed. Changes in the emission polarization peak during the cell cycle or those induced by growth stimulators and inhibitors reflect structural changes in the mitochondria on their transition from the resting, orthodox into the active, ATP-generating, condensed conformation and vice versa. Possible mechanisms for the formation of the sharp emission polarization peak are discussed.

Animals↗
PubMed2004

Intravitreal triamcinolone injection for diabetic macular edema: a clinical and fluorescein angiographic case series.

BACKGROUND: A significant number of eyes with diabetic macular edema remain refractory to treatment despite numerous attempts at photocoagulation. Triamcinolone acetonide, a minimally water soluble steroid injected in suspension form, has been reported to be a well-tolerated agent for intravitreal injection, prompting a decrease in diabetic macular edema on optical coherence tomography. We report our experience with this treatment in 19 eyes with persistent diabetic macular edema. METHODS: We reviewed the charts of 16 patients (19 eyes) from a clinical practice with diabetic macular edema persistent after focal or grid laser photocoagulation. All eyes had received 4 mg of triamcinolone, injected into the vitreous cavity 3.5 mm posterior to the limbus. Fluorescein angiography was performed before and about 2 weeks after the injection. Snellen visual acuity and intraocular pressure (as determined with Goldmann applanation tonometry) were also measured before and after the injection. RESULTS: Fluorescein angiography showed marked improvement of macular edema in 4 eyes (21.0%), mild improvement in 10 eyes (52.6%) and no change in 5 eyes (26.3%); no patient had worsening of macular edema. Visual acuity improved by at least 1 line in 13 eyes (68.4%), by 2 or more lines in 5 eyes (26.3%), by 3 or more lines in 2 eyes (10.5%) and by 4 lines in 1 eye (5.3%); visual acuity remained unchanged in 5 eyes (26.3%) and deteriorated by 1 line in 1 eye (5.3%). Intraocular pressure elevation of 10 mm Hg or greater occurred in two eyes (10.5%) and was successfully treated with topical administration of 0.15% brimonidine.The triamcinolone was well tolerated, and there were no other ocular complications. INTERPRETATION: Intravitreal injection of triamcinolone has potential in the treatment of diabetic macular edema and warrants investigation in a randomized prospective clinical trial.

Aged↗
PubMed1995

Comparison of fluorescein angiography with microvascular anatomy of macaque retinas.

Recent anatomic work has shown that the capillary network of the fovea is multilaminar. We have identified the elements of this network that are visualized by fluorescein angiography and those that are missed. Fluorescein angiograms of monkey retinas (Macaca fascicularis) with good visualization of individual capillaries were obtained by standard clinical techniques. Retinal whole mounts were prepared from the same animals. Anatomic drawings made from the whole mounts were used to identify which parts of the capillary network were visualized angiographically. Angiographic estimates of dimensions of the foveal avascular zone corresponded closely to the anatomy. Capillary visibility declined rapidly from near perfect visualization at the edge of the foveal avascular zone to less than 40% by 900 microns eccentricity. While all the widest capillary segments (diameter 6.1-7.0 microns) were visualized, only 43% of the modal group of capillary segments (diameter 4.1-4.5 microns) were detected. When a relatively homogeneous population of capillaries was analyzed (diameters limited to the narrow range of 4.0-5.0 microns), visualization declined monotonically with depth in the retina. Capillary segments in the nerve fiber plane were visualized more than four times as effectively as segments of comparable diameter in the deepest vascular plane. High quality angiograms accurately delineate the foveal avascular zone, but they visualize only a fraction of the adjacent multilaminar network. Therefore, current techniques may not detect the earliest nonperfusion of capillaries in vaso-occlusive diseases. Capillary visibility is a joint function of diameter and of retinal depth. The decline in visualization with retinal depth implies that light scattering in the retina degrades the angiographic image.

Animals↗
PubMedDate not supplied

A case of frosted branch angiitis with yellowish-white placoid lesions: fluorescein and indocyanine green angiography findings.

Severe, white sheathing of the retinal vessels and yellowish-white placoid lesions, suggesting frosted-branch angiitis, were found in both fundi of a 24-year-old woman. Fluorescein angiography showed hypofluorescence of the placoid lesions in the early phase and hyperfluorescence in the late phase. Indocyanine green angiography showed hypofluorescence during all phases. These findings imply an occlusion of the choriocapillaris. Fluorescein angiography also showed occlusion of the peripheral retinal vessels. With systemic corticosteroids and prostaglandin I2 derivative, the fundi recovered almost completely to normal 3 months later.

Adult↗
PubMed1998

Optimisation of a heterogeneous non-competitive flow immunoassay comparing fluorescein, peroxidase and alkaline phosphatase as labels.

Off- and on-line strategies for a non-competitive heterogeneous flow immunoassay were developed comparing three different labels. The samples, containing the model compounds digoxin or digoxigenin, were either pre-incubated off-line or on-line in a mixing coil with excess of labelled anti-digoxigenin Fab-fragments. The excess of Fab-fragments was then separated from the digoxin bound Fab-fragments by passing the sample through a column with immobilised digoxin. The off-line immunochemical detection system is suitable for sensitive high through-put screening of the analytes, whereas the on-line system is more suitable for coupling as a post-column detection unit to liquid chromatography. The digoxin and digoxigenin content in the sample were quantified using fluorescein (F) and enzyme (peroxidase (POD), alkaline phosphatase (AP)) labelled Fab-fragments. The fluorescein label was directly measured with the fluorescence detector, whereas a fluorescent enzyme product was measured in the two enzyme based systems, using 3-(p-hydroxyphenyl)-propionic acid (HPPA) and hydrogen peroxide for POD and, and 4-methylumbelliferyl phosphate (4-MUP) for AP. The highest sensitivity and lowest limit of detection (LOD) was obtained with the Fab-POD system with LODs for digoxin and digoxigenin in the off- and on-line configurations of 0.025 and 0.01 nM, respectively. The sample through-put for the off- and on-line systems were 43 and 32 samples per hour, respectively.

Alkaline Phosphatase↗
PubMedDate not supplied

Iris fluorescein angiography in clinical practice.

Iris fluorescein angiography is a valuable technique for elucidating a wide range of eye pathologies, among them developmental anomalies, degenerative disease, retinal vascular occlusions, diabetic microangiopathy, uveitis of various etiologies, glaucoma, tumor, and surgical or accidental trauma. In fact, IFA is more sensitive than biomicroscopy in the evaluation of iris abnormalities. Moreover, it provides indirect but reliable information on the retinal circulation when this cannot be examined directly. Some of the most important clinical applications involve the early detection of iris new vessels, cataract management in diabetic patients, and monitoring of iris tumors. Equipment, procedures, and fluorescein angiography patterns in normal and disease states are described and extensively illustrated. More widespread use of this valuable technique is encouraged.

Animals↗
PubMed2003

Agreement among ophthalmologists in evaluating fluorescein angiograms in patients with neovascular age-related macular degeneration for photodynamic therapy eligibility (FLAP-study).

OBJECTIVE: To determine intraobserver and interobserver variation for classifying types of choroidal neovascularizations (CNV) in exudative age-related macular degeneration (ARMD). DESIGN: Intraexaminer and interexaminer reliability study. PARTICIPANTS: Digital high-quality fluorescein angiograms of 40 patients with neovascular ARMD were evaluated independently by 16 retinal specialists. MAIN OUTCOME MEASURES: Fluorescein angiographies were presented in two randomized sequences (series A and B) to each masked reader for classification of type of CNV into classic, occult, or mixed with classic component of less or greater 50%. Agreement was evaluated by calculating kappa statistics (kappa) and intraclass correlation coefficients. RESULTS: The mean kappa coefficient was 0.64 +/- 0.11 for intraobserver variation, with a range from 0.44 to 0.89. For interobserver variation the intraclass correlation coefficients was calculated as 0.66 (95% confidence interval [CI] 0.56, 0.77) for series A and as 0.55 (95% CI 0.43, 0.67) for series B. CONCLUSIONS: Angiographic classification of CNV secondary to ARMD can vary considerably not only between observers but also for repeated evaluation by the same observer. Because various current and emerging treatments including photodynamic therapy are based on specific angiographic characteristics, accurate interpretation will become more important.

Choroidal Neovascularization↗
PubMed1984

Rubeosis iridis: preoperative iris fluorescein angiography and periocular steroids.

To study the risk of developing rubeosis iridis following vitrectomy, the use of preoperative iris fluorescein angiography was prospectively investigated on patients with diabetes mellitus, without any clinically detectable iris or angle neovascularization. With increasing severity of fluorescein leakage, the risk of iris neovascularization with or without glaucoma, six months after vitreous surgery, is significantly increased. It was also determined whether postoperative steroid therapy (periocular triamcinolone acetonide and topical prednisolone phosphate) reduces the risk of developing iris neovascularization after vitrectomy. Controlled and treated patient eyes did not differ significantly in the degree of rubeosis. However, neovascular glaucoma statistically occurred more frequently in the nonsteroid group.

Diabetic Retinopathy↗
PubMed1990

Anterior segment fluorescein videoangiography with a scanning angiographic microscope.

The scanning laser ophthalmoscope can be modified to operate as a scanning laser biomicroscope for use in anterior segment fluorescein angiography. The substantial depth of focus, large field of view, co-axial illumination, low light levels, real-time television operation, and videorecording with immediate recall provide advantages not available with conventional photographic methods. Video techniques give a resolution slightly inferior to photography, but this is unlikely to be significant in clinical practice. A technique of traversing the entire anterior episcleral vasculature has been developed to give a comprehensive and reproducible angiographic record. Previous fluorescein studies suggesting the primary importance of retrograde (centrifugal) flow in the perforating anterior ciliary arteries were not supported; methodologic explanations are advanced. Several principles are proposed to improve techniques of anterior segment angiography.

Adult↗
PubMed1991

Fluorescein fundus angiography with scanning laser ophthalmoscope. Visibility of leukocytes and platelets in perifoveal capillaries.

The authors performed fluorescein fundus angiography in 130 eyes using a scanning laser ophthalmoscope (SLO). Capillaries were observed in the perifoveal area in 63 eyes. In these 63 eyes, numerous fluorescent dots were seen flowing through the capillaries. This feature allowed identification of the direction and velocity of blood flow in the retinal capillaries. The distance from 1 dot to the next was widely variable and averaged 100 microM. The velocity of flow was faster in precapillary arterioles, slower in capillaries, and again faster in postcapillary venules. The dots were much more numerous in an eye with leukemia and less numerous in an eye with idiopathic thrombocytopenic purpura. Staining of whole blood from three healthy persons with fluorescein sodium resulted in prompt and intense staining of leukocytes and platelets. These findings indicate that the observed fluorescent dots in perifoveal capillaries correspond to leukocytes and platelets in the circulating blood.

Adolescent↗
PubMed1999

The importance of fluorescein angiography in planning laser treatment of diabetic macular edema.

OBJECTIVE: To test the hypothesis that pretreatment fluorescein angiography (FA) is not necessary for effective laser treatment of patients with clinically significant diabetic macular edema (CSME). DESIGN: Prospective, randomized, controlled treatment simulation. PARTICIPANTS: Six fellowship trained retina specialists. INTERVENTION: The authors compared the ability of four retina specialists (observers) to plan laser treatment with and without the use of FA. One hundred consecutive cases of CSME were selected, each case consisting of a stereo pair of color photographs and a corresponding fluorescein angiogram. These cases were first read by two retina specialists who reached consensus on a treatment plan for each case (standard map). Each of the 4 observers reviewed 50 of these cases on 2 occasions and plotted 2 sets of treatment maps, 1 set created with and 1 without the aid of FA. Each observer's 100 treatment maps were graded for accuracy by comparing them to the corresponding standard maps. The role of FA in improving the accuracy of treatment maps was evaluated using logistic regression analysis to control for different observers, different cases, and different posterior pole characteristics. MAIN OUTCOME MEASURES: Accuracy was defined as the proportion of standard treatment correctly treated by the observer. RESULTS: For the observers as a group, the use of FA improved treatment planning accuracy from 49% to 54.5% (P = 0.02); however, there was significant interobserver variation in performance (P < 0.001). Treatment planning accuracy without and with FA was as follows: observer 1, 40.8% and 40.2%; observer 2, 49.8% and 72%; observer 3, 56.1% and 59.5%; and observer 4, 49.2% and 46.4%. CONCLUSION: The use of FA improves the accuracy of treatment planning for CSME. The authors' study supports the use of FA in laser treatment of patients with CSME.

Diabetic Retinopathy↗
PubMed1997

Fluorescein-Trp25-exendin-4, a biologically active fluorescent probe for the human GLP-1 receptor.

Exendin-4, a reptilian GLP-1 analogue, has been fluorescently labeled by covalently linking a fluorescein moiety onto the Trp residue yielding fluorescein-Trp25-exendin-4 (FLEX). FLEX is equipotent to GLP-1(7-36)-amide and exendin-4 as an inhibitor of [125I] GLP-1 binding to the human GLP-1 receptor stably expressed in CHO cells, and maintains full biological potency and efficacy as measured by the stimulation of cAMP accumulation in these cells. FLEX binding to CHO/hGLP-1R membranes results in an increase in fluorescence anisotropy. The binding is specific and saturable (Kd = 2.0 +/- 0.4 nM), and GLP-1(7-36)-amide and exendin-4 are equipotent inhibitors of FLEX binding to the human GLP-1 receptor. Thus, FLEX is a potent, biologically active ligand that is useful for the study of the binding and functional characteristics of the human GLP-1 receptor.

Animals↗