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At least 505 records · Page 28Linked to original sources
PubMed2005

Detection of corneal epithelial defect through amniotic membrane patch by fluorescein.

PURPOSE: To demonstrate the usefulness of fluorescein dye to detect a corneal epithelial defect through an amniotic membrane patch in 4 cases. PATIENTS AND METHOD: Two patients with painful bullous keratopathy, 1 patient with total limbal deficiency, and 1 patient with acute chemical burn underwent surgeries in conjunction with amniotic membrane as patch. Postoperatively, slit-lamp biomicroscopic examination with and without fluorescein staining was performed. RESULTS: The status of epithelialization, ie, corneal epithelial defect on either denuded corneal stroma or amniotic membrane graft, was indiscernible by slit-lamp biomicroscopy through the amniotic membrane patch. Nevertheless, it could be detected by fluorescein staining, especially after saline rinse, in all 4 cases. CONCLUSIONS: Fluorescein staining permits clinicians to avoid prematurely removing the amniotic membrane patch during the treatment of a persistent corneal epithelial defect.

Administration, Topical↗
PubMed2003

The use of fluorescein-enhanced quantitative light-induced fluorescence to monitor de- and re-mineralization of in vitro root caries.

The use of fluorescein-enhanced quantitative light-induced fluorescence (QLF) in the detection of in vitro root caries demineralization and reminerlization was investigated. Fourteen previously extracted human premolar roots were selected and determined to be caries-free. Cementum was removed and nail varnish applied leaving an exposed window. Positive and negative controls were selected. During a demineralizing regimen, roots were removed at regular intervals (12, 48, 72 and 120 h) and immersed in sodium fluorescein (0.2 mg L(-1)). Following gentle rinsing, each root was examined using QLF before being returned to the demineralizing solution. Following 120 h, each tooth was sectioned through the lesion and one-half retained for transverse micro radiography (TMR) analysis. The remaining half were subjected to a remineralizing regimen undergoing the same fluorescein and QLF examinations at 7, 28 and 36 days. Results showed that QLF effectively monitored demineralization/remineralization of root dentine as represented by fluorescein penetration. TMR analysis showed good correlations with QLF (DeltaZ/DeltaQ) after demineralization (r = 0.89) and remineralization (r = 0.84). The technique could represent an in vivo method for root caries detection and classification.

Bicuspid↗
PubMed2003

Evaluation of intravenous fluorescein in intradermal allergy testing in psittacines.

This study was designed to improve the clinical feasibility of intradermal skin testing of psittacine birds using intravenous fluorescein stain. Twenty-five healthy, anaesthetized Hispaniolan Amazon parrots (Amazona ventralis) were injected intravenously with 10 mg kg-1 fluorescein-sodium 1% followed by intradermal injections of 0.02 mL phosphate-buffered saline, histamine phosphate (1:100,000 w/v) and codeine phosphate (1:100,000 w/v) at the sternal apteria. Wheal diameters of reaction sites were measured grossly and under illumination with a Wood's lamp after 5 and 10 min. Fluorescence-enhanced injection sites were scored between 0 and 2, with 0 equivalent to normal skin and 2 equivalent to a plucked feather follicle. The presence of a fluorescent halo around intradermal injections was also recorded. Under Wood's light illumination at 10 min, histamine and saline were evaluated as positive and negative controls, respectively, based on a positive test having a halo and a score of 2. Sensitivity and specificity were each 76% for halo, 84 and 42% for score and 64 and 77% for combination of score and halo, respectively. Further, mean histamine reactions were significantly larger than codeine phosphate and saline (8.8 +/- 0.4 mm; 7.2 +/- 0.3 mm; 5.9 +/- 0.6 mm); however, this finding was not consistent in individual birds. Wheal size, halo presence and score were affected by site location independent from the injected compound. Intravenous fluorescein improved the readability of avian skin tests; however, the compounds tested raised inconsistent reactions in wheal size, score or halo presence. The compound-independent site effect raises concern on the validity of avian skin testing and warrants investigation of other techniques such as in vitro allergy testing. Based on our findings, intradermal allergy testing in psittacines with or without fluorescein is unreliable and cannot be recommended for practical clinical use.

Animals↗
PubMed1976

pK changes of ionizable reporter groups as an index of conformational changes in proteins. A study of fluorescein-labelled ribonuclease A.

A chemical derivative of bovine pancreatic ribonuclease A (RNase A) has been prepared by reaction with fluorescein-isothiocyanate at pH 6. This derivative has a fluorescein group covalently attached to the alpha-amino group of the protein. The enzymic properties of the modified protein are similar to those of RNase A. It is shown that the pK of the fluorescein group can be used as an index of protein conformation to monitor structural changes in the protein. In this work, the binding of a specific inhibitor (cytidine 2'-monophosphate) to RNase A, the isomerization process occurring in RNase A around pH 6, and the thermal unfolding of RNase A, were studied by mean of the pK changes of the fluorescein group. The results obtained by this method are fully consistent with those obtained by other methods. It is proposed that using ionizable reporter groups and their changes in pK to monitor conformational changes in proteins may be a sensitive tool both in equilibrium and kinetic studies.

Amino Acids↗
PubMed1994

No intermediate channelling in stepwise hydrolysis of fluorescein di-beta-D-galactoside by beta-galactosidase.

For the hydrolysis of the two glycosidic bonds of fluorescein di-beta-D-galactoside (FDG) by beta-galactosidase from Escherichia coli, small [Hofmann, J. & Sernetz, M. (1983) Anal. Biochem. 131, 180-186] to dramatic [Huang, Z. (1991) Biochemistry 30, 8535-8540] deviations from simple stepwise substrate-intermediate-product kinetics have been reported. Intermediate channelling, a preferred hydrolysis of the intermediate fluorescein mono-beta-D-galactoside (FMG) formed from FDG at the active site and thus in a favourable position for further reaction, has been postulated. As there were reasons to doubt the previous findings and conclusions, the hydrolysis experiments have been repeated at initial FDG concentrations of 7-200 microM, following the concentrations of FDG, FMG and fluorescein with a reliable method, quantitative HPLC, to completion of the reaction. The transient appearance of substantial amounts of the intermediate FMG also in experiments with 200 microM FDG already rules out the existence of the most efficient intermediate channelling deduced by Huang (1991) from measurements of the initially developing fluorescence, incorrectly ascribed to fluorescein. Redetermination of the Michaelis constants for FDG and FMG led to much higher values than those reported previously. Fitting the progress curves by means of nonlinear regression combined with numerical integration of the rate equations resulted in good fits of the normal stepwise substrate-intermediate-product mechanism, without any necessity of assuming a more complex course of the reaction. So one of the rare examples of the hydrolysis of two bonds at a single enzyme-substrate encounter has been invalidated.

Chromatography, High Pressure Liquid↗
PubMedDate not supplied

Comparative fluorescein angiography of the normal sheep and goat ocular fundi.

Fluorescein angiography without sedative or anesthetic agents was evaluated in 20 normal goats and 20 normal sheep. All of the angiographic phases were observed using 20 mg/kg fluorescein IV in both species. Fundus fluorescein angiography results revealed wide stars of Winslow in the tapetal fundus, central or marginal flow during the first part of the arterial phase, delayed filling of the focal areas in the choroid near the optic disc that often coincided with others in the disc, and lack of evidence of the 'striate area' in the tapetal fundi. In goats, the angiographic times were 6.54+/-1.25 s for the arterial phase (TA), 7.80+/-1.37 s for the arterio-venous phase (TAV), and 14.13+/-2.01 s for the venous phase (TV). I1: 1.30+/-0.30 s (time elapsing between TA and TAV), and I2: 6.20+/-1.60 s (time elapsing between TAV and TV). In sheep, times were 9.54+/-2.18 s TA, 11.73+/-2.10 s TAV, and 20.86+/-2.74 s TV. I1: 2.04+/-0.75 s and I2: 8.98+/-2.47 s, respectively. Due to the large size of the fundic vessels in sheep and goats, fluorescein angiography of the retinal vasculature can facilitate the study of the different vascular diseases in these species.

Animals↗
PubMed2006

Fluorescein filling defects of the optic nerve head in normal tension glaucoma, primary open-angle glaucoma, ocular hypertension and healthy controls.

BACKGROUND: To evaluate fluorescein filling defects of the optic nerve head in normal tension glaucoma (NTG), primary open-angle glaucoma (POAG), ocular hypertension (OHT) and controls. METHODS: Forty patients with NTG (mean age 55 +/- 10 years), 40 patients with POAG (mean age 55 +/- 11 years), 40 patients with OHT (mean age 53 +/- 13 years), and 40 age-matched controls (mean age 54 +/- 11 years) were included in a prospective study. Video fluorescein angiograms were performed by means of a scanning laser ophthalmoscope. The extent of absolute filling defects of the optic nerve head was assessed (as a percentage of the disc area) using digital image analysis. Visual fields were tested by automatic static perimetry (Humphrey Field Analyzer, programme 24-2). RESULTS: Absolute filling defects were significantly larger in patients with NTG (12.2 +/- 15.5%) and POAG (12.9 +/- 13.1%) compared to patients with OHT (1.2 +/- 3.6%) and healthy controls (0.1 +/- 0.5%) (p < 0.0001). The area under the receiver operating characteristic (ROC) curve was 0.806 for NTG vs healthy controls, and 0.812 for POAG vs OHT. Absolute filling defects are significantly correlated to the global indices mean deviation (r = -0.63, p < 0.0001), pattern standard deviation (r = 0.61, p < 0.0001), and corrected pattern standard deviation (r = 0.62, p < 0.0001) and significantly correlated to horizontal (r = 0.50, p < 0.0001) and vertical (r = 0.53, p < 0.0001) cup-to-disc-ratios. CONCLUSIONS: Fluorescein filling defects of the optic disc representing capillary dropout are present in NTG and POAG. The extent of these filling defects is correlated to visual field loss and morphological damage. Fluorescein angiography may be useful in the diagnosis and management of NTG and POAG.

Blood Pressure↗
PubMed1982

Fluorescein in human plasma in vitro.

A method to determine fluorescein in human plasma is described. By aid of ultrafiltration a separation between fluorescein bound to plasma proteins and fluorescein free in the water is obtained. Both fractions are quantitated. Fluorescein is bound to plasma proteins. The protein binding is reversible, not sensitive to practically appearing changes in pH, temperature and gas tensions. For a normal person it appeared that at a total plasma concentration between (10(-6) - 10(-4))g . ml-1 approximately 15% was free while at a total concentration of 10(-3) g . ml-1 45% was free, pointing towards a limited amount of protein binding sites.

Blood↗
PubMed1982

Fluorescein in human plasma in vivo.

In connection with corpus vitreum fluorophotometric examinations fluorescein was injected iv and fluorescein in the blood stream was studied with respect to protein binding and elimination kinetics. It was shown by ultrafiltration that in blood obtained during the examination most of the fluorescein was protein bound, and only a minor fraction (10-20%) was free in the water phase. While the free fraction was approximately constant over a wide concentration range when studied in vitro the free fraction increased by a factor of about 2 during a 2 h examination period in vivo. The curve describing the elimination of fluorescein from blood showed a polyexponential decline course. The area under this curve showed only a small variation for the same normal person examined 3 times over a period of 6 months. The area under the bolus has a magnitude, which is 30-40% of that under the rest of the curve.

Blood↗
PubMed1967

The active transport of fluorescein by the retinal vessels and the retina.

1. The movement of fluorescein across the retinal surface of the rabbit's eye was estimated by measuring the concentration gradient of the dye in the vitreous body. These measurements were made in vivo by means of a slit-lamp fluorophotometer, or were taken from frozen sections of enucleated eyes.2. In the normal eye, fluorescein does not pass from the blood to the vitreous body across any part of the retina. When injected into the vitreous body it passes rapidly out across the entire retinal surface, even against a very large concentration gradient.3. A variety of metabolic and competitive inhibitors, effective in blocking organic anion transport in the kidney and liver, tend to abolish this unidirectional movement of fluorescein across the retina.4. The region occupied by the retinal vessels is more sensitive to inhibition than other areas of the retina. Occlusion of the vessels by diathermy prevents the exchange of fluorescein in this region.5. It appears, then, that there is an active transport of organic anions out of the vitreous body, both by the retinal capillaries and by the retina itself. The latter system is probably located in the pigment epithelium and seems to be carried forward to the rear surface of the iris.6. Since the walls of the retinal vessels of the rabbit are freely in contact with the vitreous body, the active transport must take place across the capillary endothelial cells themselves. These vessels have structural and permeability characteristics found only in the central nervous system and it is to be presumed that the anion transport system is shared by the capillaries of the brain.7. The function of the transport in the retina may be to protect the nervous tissue from toxic materials by preventing their entry from the blood or by removing products of metabolism conjugated as organic anions. Alternatively, the mechanism may be concerned in maintaining the normal adhesion of the retina to the choroid, since retinal detachment was observed to follow its total inhibition.

Animals↗
PubMed1966

Rapid fluorescein and protein assay method for fluorescent-antibody conjugates.

A method is presented for the rapid determination of the fluorescein content, protein content, and fluorescein-to-protein ratio for immune globulin conjugates with fluorescein isothiocyanate as the fluor. This method is based on the absorbance of the fluorescent antibody at those wavelengths primarily associated with the fluorescein and gamma-globulin fractions, and permits these materials to be determined by a single nondestructive analytical procedure. A small sample of the fluorescent antibody, in many cases 0.1 ml or less, is adequate for the above determinations. A nomograph is presented which allows simultaneous determination of the materials from the observed absorbance at the two wavelengths. The method is sufficiently accurate for most applications of the fluorescent-antibody techniques. Although this procedure has been developed primarily for fluorescent-antibody conjugates prepared from rabbit gamma-globulin, it can be used directly for antibodies prepared from other animals provided the gamma-globulin is relatively free from albumin.

Animals↗
PubMed1986

Diagnosis of exocrine pancreatic insufficiency in cystic fibrosis by use of fluorescein dilaurate test.

In the fluorescein dilaurate test fluorescein dilaurate is cleaved by the pancreas specific cholesterol ester hydrolase activity and the liberated fluorescein is absorbed and excreted in the urine. Fluorescein recovery is a reflection of exocrine pancreatic function. The test was evaluated in 14 patients with cystic fibrosis and 16 healthy volunteers. The test was well tolerated by patients, was easy to perform, and gave significantly lower values in the patients suffering from cystic fibrosis. The result of the pancreolauryl test was also correlated with the result of the faecal chymotrypsin test in 11 of the patients suffering from cystic fibrosis. A positive correlation was found between the two test results. The test is a practical and reliable index of pancreatic exocrine function and may have a useful role as a screening procedure.

Adolescent↗
PubMed1977

Fluorescein angiography of the hereditary choroidal dystrophies.

The hereditary choroidal dystrophies are divided into (1) geographic choroidal dystrophies (central areolar, peripapillary, generalised), (2) gyrate atrophy, and (3) choroideremia. Each of these disorders is discussed with regard to mode of inheritance, age of onset, symptoms, fundus appearance, and visual function testing. A typical case history of each disorder is presented together with fluorescein angiography, and the fluorescein angiographic findings are related to our present understanding of these diseases. Fluorescein angiography was found to be most helpful in diagnosing the early cases, by confirming the absence of the choriocapillaris, and in demonstrating either a local or general abnormality. The role of fluorescein angiography in understanding the aetiology of choroidan dystrophies is discussed.

Adolescent↗
PubMed1977

Fluorescein pupillary flow in aphakics with intact and spontaneous openings of the vitreous face.

The passage of fluorescein dye, injected into the general circulation, from the posterior to the anterior chamber was studied in 60 selected aphakic eyes between 2 days and 4 weeks after an uneventful cataract extraction. In a group of 22 eyes with intact anterior hyaloid, fluorescein was seen to pass only through the pupillary margin, mostly within 20 seconds of the beginning of the eye injection. In 24 eyes with rents in the anterior hyaloid the dye was seen percolating only through the vitreous face openings. No fluorescein passed through the pupillary margin or the peripheral iridectomy in this group of eyes. The appearance time of the dye was delayed to about twice the normal appearance time. In 8 eyes with rents in the anterior hyaloid the dye passed only through the pupillary margin. In 4 eyes with anterior vitreous rents the fluorescein appeared through the anterior vitreous face opening. From the analysis of the data it appears that the spontaneous breaks in the anterior vitreous face may represent a 'self-c,re' of pupillary and iridectomy block by the vitreous in aphakics in a high proportion of cases. It is our impression that 3 peripheral iridectomies and a very tight closure of the wound can prevent the complication of spontaneous breaks of the vitreous face.

Cataract Extraction↗
PubMed1996

Peripapillary fluorescein angiographic findings in primary open angle glaucoma.

BACKGROUND: Detailed fluorescein angiographic findings in the disc circumference may be useful for evaluating the possible relation of the circumference to glaucomatous nerve damage. METHODS: Fluorescein angiograms of 25 eyes of 25 subjects with primary open angle glaucoma were observed after they had undertaken Octopus perimetry. Based on the retinotopic projection, disc sectors and corresponding visual field regions were set. RESULTS: Twenty three eyes (92%) showed a zone of no fluorescence around the disc (non-fluorescent zone). Of these, the zone width of the 20 eyes that had visible ciliary vessels within the zone was wider than that of the other three eyes, and showed fluorescein diffusion from the outer boundary of the zone towards the disc. The diffusion reached the disc if the zone was narrow. In those 20 eyes, a standardised difference in the zone width of inferior temporal sector minus superior temporal sector correlated with the difference in mean loss of corresponding visual field regions (r = 0.48, p = 0.0312). CONCLUSION: The visible ciliary vessels suggest the absence of the choriocapillaris in the non-fluorescent zone, the width of which correlated with the visual field defect and may affect the amount of the fluorescein diffusion to the disc. This suggests that the diffusion might be related to optic nerve damage in glaucoma.

Female↗
PubMed1997

Peripapillary circle of Zinn-Haller revealed by fundus fluorescein angiography.

AIMS: To observe the vascular pattern of the peripapillary circle of Zinn-Haller in humans by fundus fluorescein angiography. METHODS: 307 cases (from 212 patients) of fundus fluorescein angiograms performed in patients with myopic degeneration were evaluated to find the circle of Zinn-Haller and to observe its fundus fluorescein angiographic features. RESULTS: 15 cases (from 13 patients) with the circle of Zinn-Haller were found. It appeared as concentric or zigzag-shaped vascular fillings within the temporal crescent region. All cases were observed in pathological myopia with peripapillary atrophy and a tilted disc. Each arterial circle showed variations in location and shape. CONCLUSIONS: The temporal part of the circle of Zinn-Haller can be revealed by fundus fluorescein angiography particularly in pathological eyes with prominent peripapillary atrophy and a tilted disc. The morphological variation of this arterial circle should be considered.

Adult↗
PubMed1971

Comparison between thermography and fluorescein test in the detection of incompetent perforating veins.

Incompetent perforating veins of the legs were located by dynamic thermography at 69 sites and by the fluorescein test at 31. All the sites were explored by multiple local incisions. Incompetence of the veins was determined by demonstrating retrograde blood flow through these veins when severed. Explorations of these sites showed that thermography detected 94% and gave false-positive results in 6%, while the fluorescein test detected 16% and contributed 84% false-positive results. These findings show a highly significant difference (P <0.0005) in favour of the thermographic technique. Detection of 16% of incompetent perforating veins by the fluorescein test is statistically insignificant. This inaccuracy is thought to be due to inadequate dermal penetration of the ultraviolet rays. A positive fluorescein test probably indicates the presence of incompetent perforating veins but has little anatomical relationship to their actual site.

False Negative Reactions↗
PubMed1993

Inhibition of the red blood cell calcium pump by eosin and other fluorescein analogues.

This paper addresses the mechanism of inhibition of the plasma membrane Ca pump by fluorescein analogues and their isothiocyanate derivatives. Eosin (i.e., tetrabromofluorescein) was found to be one of the most potent reversible inhibitors of the erythrocyte Ca pump [half-maximal inhibitory concentration (IC50) < 0.2 microM]; fluorescein itself was about four orders of magnitude less potent (IC50 approximately 1,000 microM). Eosin decreased the maximum influx and thus did not compete with ATP for the Ca pump. Irreversible inhibition produced by the isothiocyanate analogues of eosin and fluorescein [eosin 5-isothiocyanate (EITC) and fluorescein 5-isothiocyanate (FITC), respectively] was also studied. While EITC bound reversibly at the eosin site, two results suggest that EITC does not react covalently at this site: 1) eosin did not alter the time course of the EITC irreversible reaction, and 2) the concentration dependence for reversible EITC inhibition was different from the concentration dependence for irreversible EITC inhibition. ATP did slow the rate of inactivation of both EITC and FITC consistent with the idea that EITC and FITC bind to the ATP site. Our results are consistent with eosin and ATP binding to separate sites and EITC reacting covalently at the ATP site, but not the eosin site.

Adenosine Triphosphate↗