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At least 649 records · Page 36Linked to original sources
PubMed1996

Indocyanine green and fluorescein angiography of surgically excised macular choroidal neovascularizations: correlations with histopathologic and ultrastructural findings.

BACKGROUND: Informations are expected from the histopathological study of surgically excised choroidal neovascular membranes (CNMs), particularly in relation to the angiographic aspects of vascular architecture. METHODS: Fluorescein and indocyanine green (ICG) angiograms were studied together with the histopathological features of 12 surgically excised subfoveal CNMs in eyes affected by age-related macular degeneration (ARMD). RESULTS: Instead of the early and delayed diffuse hyperfluorescence secondary to CNMs observed on fluorescein angiography (seven were well defined, five scar evolved), ICG revealed (a) very early hypofluorescence of the membrane bulk over the fluorescence of the outer choroidal vascular bed and (b) late hyperfluorescence gradually increasing and partially defining the border of membranes. CNMs with well-defined hyperfluorescent aspects were characterized by fibrovascular bulk lined on one side by retinal pigment epithelium. Fibrosis reaction predominated over the vascular components in scar-evolved membranes. CONCLUSIONS: Fluorescein and ICG angiographic differences in the appearance of CNMs could depend on (a) the morphological structure and size of the CNM (b) its location within the chorioretinal layers and (c) different molecular characteristics of the dyes used.

Aged↗
PubMed1979

Fluorescein angiography and changes in aqueous humor protein after argon laser photomydriasis in rabbits.

In brown-eyed and blue-eyed rabbits, irises treated with argon laser photomydriasis (ALP) were studied by using fluorescein angiography and by evaluating the aqueous humor protein concentration. The following results were obtained. Immediately after ALP, a breakdown of the blood-aqueous barrier is demonstrated by a marked influx of fluorescein into the ciliary processes and into the anterior and posterior chambers. The dye flow into the aqueous humor decreases to normal values within 3 days. There is no fluorescein leakage from laser impacts themselves. Peripupillary capillary loops are permanently occluded, but in a few cases, recanalization occurs. Neovascularization did not occur during 56 days of observation. ALP initially leads to a six- to eightfold increase in normal aqueous humor protein concentration, which decays to normal values within 3 days.

Animals↗
PubMed1976

[Standardized fluorescein injection in serial angiography (author's transl)].

Maximal initial dye concentration in the retinal arteries is desirable for high quality fluorescein Angiograms and is essential for circulation studies. Such high initial dye concentrations can only be achieved by a very rapid fluorescein injection technique necessitating an automatic injector. A reliable easy to use "spring-injector" has been designed for clinical use (Figs. 1 and 2). A disposable syringe is driven by a spring contained in a metal cylinder. Microswitches are activated by the piston of the injector triggering one exposure each at the beginning and at the end of the injection. Time and duration of the injection are therby permanently documented on the film. The "Terumo Disposable Syringe 10 cc" is used routinely. By interposing a plastic connector between syringe and injector-piston the injection-volume can be reduced to 5 ml. With diffferent connectors one can inject an volume desired up to 10 ml. The duration of the injection can be varied by using different intravenous catheters. Routinely the "VYGON Trocaflex catheter Nr. 125.16" with a needle diameter of 1.1 mm and a length of 30 cm is used resulting in an injection time of 10 ml/1.0 sec or 5 ml/0.5 sec. The largest Trocaflex catheter (No. 125.20) will shorten the injection time to 10 ml/0.5 sec and 5 ml/0.25 sec respectively. Even faster injections can be achieved by shortening the catheter or by using a stronger spring. With the described injector, high-speed, well-standardized fluorescein injections are possible. The intravenous catheter makes parvenous injections impossible and will allow for repeated angiograms even on different days without the need for a new venous puncture.

Fluorescein Angiography↗
PubMed1981

Cytochemical hybridisation with fluorochrome-labelled RNA. III. Increased sensitivity by the use of anti-fluorescein antibodies.

A new method to localise specific DNA sequences in microscopic preparations by hybridocytochemistry using fluorochrome labelled complementary RNA has been described recently (Bauman et al. 1981). The present paper describes a procedure to increase the sensitivity of this method. RNA complementary to kinetoplasts DNA of Crithidia luciliae was labelled with fluorescein and hybridised with Sephadex beads to which kinetoplast DNA or heterologous DNA had been covalently bound as well as to Crithidia luciliae preparations. The fluorescein-labelled RNA was found to hybridize specifically with homologous DNA both on the beads and in the cells. The sensitivity of the hybrid detection could be increased by applying an indirect immunofluorescence reaction using rabbit antiserum raised against the hapten fluorescein as has been described for the amplification of a direct immunofluorescence reaction by Schmitz and Kampa (1979). The complete procedure resulted in an amplification of the original specific fluorescence both on the beads and in the cells. The increase was quantified by microfluorimetry. Several aspects of the immunocytochemical amplifying reaction were quantitatively investigated using Sephadex beads to which poly(A) or DNA was coupled and FITC-labelled poly(U) or cRNA was hybridised. A 5- to 10-fold amplification was obtained both in the beads and on the cell preparations. When the amplifying steps were repeated a proportional increase in background fluorescence was observed.

Crithidia↗
PubMed1975

Provoked iris ischaemia in the rabbit. II. Histochemical localization of sodium fluorescein.

The distribution of injected sodium fluorescein in the iris and ciliary body of albino rabbits was studied in normal animals and in animals subjected to different surgical procedures. The study was performed with two techniques: whole-mount preparations and the paraffin-section method on freeze-dried eyes. Fluorescein distribution showed marked changes after surgical procedures as a result of reduced blood perfusion. In normal iris vessels no penetration of fluorescein was observed. The permeability barrier was impaired if there were ischaemic conditions in the anterior segment. The results were compared with clinical and iris angiographic studies.

Animals↗
PubMed1978

Effects of X-rays on cell membranes. II. Changes of permeability measured by fluorescein efflux.

The effect of irradiation on the permeability of cell membranes of L-929 cells was investigated. Efflux of fluorescein, accumulated by hydrolysis of fluoresceindiacetate in the cells, was measured using flow cytometry. The changes of rate constants for the permeation of florescein through the cell membrane at different temperatures and after various X-ray doses were studied. Decreasing temperatures yielded substantially slower efflux of fluorescein. After irradiation of cells, the rate constant of fluorescein efflux increased linearly with dose; 180 Gy are required to cause an increase by a factor of 2. The results are discussed with respect to radiation damage of active and passive transport mechanisms.

Cell Membrane Permeability↗
PubMed2003

Laparoscopic evaluation of intestinal ischemia using fluorescein and ultraviolet light in a porcine model.

BACKGROUND: The laparoscopic use of fluorescein and ultraviolet light may be a useful diagnostic tool that potentially could reduce the time until diagnosis and the subsequent mortality of mesenteric ischemia. METHODS: Eight pigs were subjected to a pneumoperitoneum pressure of 7 mmHg, and another eight pigs were exposed to a pressure of 14 mmHg. A segment of small bowel was devascularized. Two filters were used to create ultraviolet light. Pigs from each pressure group were given various intravenous fluorescein doses. The ischemic segment of the small intestine and other structures were inspected laparoscopically with the filters attached. A videotape was evaluated by resident and attending surgeons. RESULTS: Ischemic bowel was seen as a darkened silhouette against the viable fluorescent tissue. Overall, the results show that the use of ultraviolet light and fluorescence in the laparoscopic model is adequate for allowing the identification of ischemic bowel. CONCLUSIONS: The laparoscopic use of ultraviolet light combined with intravenous fluorescein dye is an effective diagnostic tool for evaluating mesenteric ischemia in pigs.

Animals↗
PubMed2004

Proposal for two strategies to prevent remnants of gastric cancers after endoscopic mucosal resections: fluorescein electronic endoscopy and rapid stump diagnosis based on pit patterns.

BACKGROUND: The aim of the present study was to establish strategies to prevent cancer remnants after gastric endoscopic mucosal resection (EMR). METHODS: Whether surgical stumps could be diagnosed by pit patterns was examined on 38 well-fixed EMR materials. Furthermore, a rapid stump diagnostic method, which enables pit patterns of EMR material to be observed within 10 min, was developed. This rapid stump diagnosis was tested in 6 EMR cases of early gastric cancers, one of which was absolutely obscure to routine endoscopy. Fluorescein electronic endoscopy had been performed to reveal the extent of this cancer before EMR. RESULTS: Adenocarcinomas showed irregular pit patterns that were significantly different from those of normal gastric mucosae. Among the 38 cases, all 20 EMR materials that were diagnosed as stump (-) and 5 that were diagnosed as stump (+), based on pit patterns, were confirmed by tissue sections to be stump (-) and stump (+), respectively. Six of the 13 EMR materials diagnosed as stump (+/-) by pit patterns were finally diagnosed as stump (+) by tissue sections. These data indicate that cancer remnants could be avoided if the stumps were judged positive or suspiciously positive just after EMR, and additional resections were continuously done until the stumps became negative. Rapid stump diagnosis based on pit patterns was successful in all 6 tested cases. The extent of the early gastric cancer that was absolutely obscure to routine endocscopy was clearly and exactly revealed by fluorescein electronic endoscopies done before EMR and subsequent rapid stump diagnosis. CONCLUSION: It is probable that fluorescein electronic endoscopy, as a precise preoperative examination, and rapid stump diagnosis, based on pit patterns, will become effective strategies to prevent cancer remnants after EMR.

Adenocarcinoma↗
PubMed1976

Fluorescein oropharyngoscopy.

To evaluate patency of the lacrimal system, fluorescein was instilled in the conjunctival cul-de-sac and the posterior oropharynx was examined with ultraviolet light. In 20 normal patients fluorescein was evident in one to 30 minutes. In cases of complete nasolacrimal duct blockage no fluorescein appeared after two hours.

Adolescent↗
PubMed1989

Detection of DNA targets with biotinylated and fluoresceinated RNA probes. Effects of the extent of derivitization on detection sensitivity.

The substituted nucleotide aminohexyl-ATP (AH-ATP) was used for synthesis of RNA probes from a plasmid template using the T7 phage promoter. Following synthesis, RNA probes were modified by reaction with N-hydroxysuccinimide (NHS) esters of biotin or fluorescein. Nearest-neighbor analysis was used to quantitate both the incorporation of the substituted nucleotide into RNA and the subsequent modification of the incorporated nucleotide by the NHS esters. The results indicate that AH-ATP is efficiently incorporated into RNA and that modification of the amine group is also efficient. The T7 polymerase shows a bias for ATP over AH-ATP and truncated transcripts are produced if 100% AH-ATP is used for synthesis. However, the use of 50% AH-ATP in the synthesis reaction yields full-length RNA probes that contain on average one amine-labeled nucleotide every 12 bases. This RNA is readily modified by the respective NHS esters to obtain one biotin group per 15-18 total RNA bases or one fluorescein group per 25-35 bases. Probes modified with biotin or fluorescein were used to detect picogram levels of target DNA in a dot blot hybridization format.

Adenosine Monophosphate↗
PubMed1979

On the active transport of organic acids (fluorescein) in the choroid plexus of the rabbit.

The kinetics of active transport of an organic acid (fluorescein) through the membranes of the choroid plexus from the lateral ventricules of the brain of rabbit was studied both morphologically and functionally. It was shown that fluorescein is actively translocated through the apical and basal membrane of the epithelium and is accumulated in blood capillaries at a concentration exceeding one order of magnitude that in the incubation medium. The kinetic curves displaying saturation and the demonstration of inhibition by other acids shows that a specific carrier is involved in the transfer across the membrane. The active transport of fluorescein at 20 degrees C was found to be sodium independent. Total exclusion of sodium from the incubation medium does not change the Michaelis constant (Km) and maximal velocity (V). The active transport depends on the operation of (Na+ + K+)-ATPase as energy source but obviously no specific complexes with the participation of sodium are involved.

Animals↗
PubMed1975

Interaction of 4,5-dibromo-2,7-di-(acetatomercuri)-fluorescein with DNAs of different base composition.

The changes in absorption spectra in the visible region observed on adding different naturally occurring and synthetic DNA duplexes to solutions of 4,5-dibromo-2,7-di-(acetatomercuri)-fluorescein indicate that the mercurial reacts with polynucleotides of this type. The reaction is reversible as proved by adding excess of KCN which restores the original spectra of the free dye. The interaction is characterised also by quenching of the fluorescence of the dye and the induction of optical activity in it. The extent of these spectral effects depends strongly on the (A+T) content of the complexed DNA and decreased in the order: poly [d(A-T)], Clostridium perfringens DAN, Escherichia coli DNA, Micrococcus luteus DNA and poly(dC). From equilibrium-dialysis experiments the same order in affinity is obtained when these poly-nucleotides are at equilibrium with the same concentration of 4,5-dibromo-2,7-di-(acetatomercuri)-fluorescein. From the changes produced by different mercurials in the ORD spectra and viscosity of a DNA solution it has been concluded that 4,5-dibromo-2,7-di(acetatomercuri)-fluorescein does not cause any drastic alteration of the secondary structure of DNA.

Animals↗
PubMed1985

Dependence of the fluorescence of fluorescein labelled (Ca2+, Mg2+)-ATPase upon the lipid to protein ratio in sarcoplasmic reticulum reconstituted systems.

Reconstituted sarcoplasmic reticulum (SR) vesicles have been prepared mixing fluorescein labelled SR, excess endogenous lipids and deoxycholate by a rapid dilution protocol and several freeze-thaw treatments. We have found that both the steady-state level and the polarization of fluorescein fluorescence of these reconstituted systems monotonically increase as a function of the lipid to protein ratio between 80 and 2000 (on a mole per mole basis). The magnitude of this increase is about 15%. Detergents, such as Triton X-100 and deoxycholate, when added to SR labelled vesicles below their critical micelle concentrations also induce similar changes in fluorescein fluorescence. We suggest that lipid dilution of protein in these reconstituted systems induce a decrease of the level of self-quenching by promoting dissociation of (Ca2+, Mg2+)-ATPase.

Animals↗
PubMed1983

Quantification of fluorescein distribution to strangulated rat ileum.

Following various periods of strangulation, the fates of intestinal segments were predicted by standard clinical criteria and visual (Wood's lamp) and fluorometric (perfusion fluorometer) assessment of fluorescein distribution. With fluorometry, a means of quantifying fluorescence transmitted via a fiberoptic light guide, the delivery and removal of fluorescein were monitored and analyzed. If either was restricted significantly, tissue death was predicted. Analysis of computerized graphic patterns or simple interpretation of fluorometric readings at two time points predicted tissue fate with 98% accuracy and a 93% negative predictive value. Wood's lamp evaluation had only a 53% accuracy and a 33% negative predictive value, while standard clinical criteria had an 81% accuracy and a 53% negative predictive value. Fluorescein leakage in segments which suffered significant endothelial damage provided staining patterns that incorrectly suggested viability. By monitoring elimination as well as uptake of dye, fluorometry provided much greater discrimination than did Wood's lamp inspection in this setting. In addition, fluorometry was readily repeatable within minutes, as fluorescence remaining from a previous injection could be subtracted from new, postinjection values.

Animals↗
PubMed1982

A study of vascular permeability in normal skeletal muscle and inflammatory myopathies using a fluorescein dye technique with percutaneous needle biopsy.

Percutaneous needle biopsy of the vastus lateralis muscle was performed immediately prior to the intravenous injection of 5 ml of 20% fluorescein sodium, in 2 control subjects and 2 patients with polymyositis. Repeat biopsies were performed 5, 10 and 15 minutes after injection. Similar biopsies were taken prior to, and 10 minutes after, fluorescein injection in 1 control subject and 15 patients with a variety of inflammatory muscle conditions including polymyositis, some of whom were on treatment with corticosteroids. Apart from one patient, with polymyalgia rheumatica, increased penetration of dye was found only in those patients with polymyositis, particularly around areas of cellular infiltration, necrosis and phagocytosis and in the periphery of muscle fibres. Corticosteroid therapy appeared to reduce the amount of dye permeating muscle tissue in patients with polymyositis. It is suggested that reducing the abnormally increased vascular permeability in damaged muscle from patients with polymyositis may represent one mode of action of corticosteroids in this condition, and that the amount of fluorescein permeating muscle may be helpful in the diagnosis where conventional clinical and histological criteria are not conclusive.

Biopsy, Needle↗
PubMed1991

Rhinovirus 3C protease catalyzes efficient cleavage of a fluorescein-labeled peptide affording a rapid and robust assay.

The 3C protease encoded by human rhinovirus type 2 catalyzes with equal efficiency cleavage of a peptide substrate with or without a fluorescein label attached to the amino acid at the P7' position. Substrates Ac-MEALFQGPLQYKDL-NH2 and MEALFQGPLQYKE(fluorescein)L are hydrolyzed with values of Vmax/KM of 970 M-1 s-1 and 1100 M-1 s-1, respectively. With the labeled substrate, HPLC achieves separation of substrate and product in 2.5 min. Separation in as little as 12 s is feasible. Fluorescein was derivatized so that it could be incorporated into peptides using automated solid-phase peptide synthesis.

3C Viral Proteases↗
PubMed1987

The Allen test--an investigation of its accuracy by fluorescein angiography.

Six consecutive patients whose clinical Allen test suggested a non-patent radial artery have been investigated by intra-arterial fluorescein angiography. Cannulation of the radial artery and injection of fluorescein typically perfused only the thumb and thenar eminence. Occlusion of the ulnar artery, leaving the radial artery as the dominant supply, resulted in fluorescein perfusion of the entire hand. It is concluded that the Allen test is of no clinical value.

Adolescent↗
PubMed1988

Polar fluorescein derivatives as improved substrate probes for flow cytoenzymological assay of cellular esterases.

Fluorescein esters are employed in assays of cell viability, membrane permeability and esterase activity. The ester most widely used, fluorescein diacetate (FDA), has the disadvantage of rapid cellular efflux of its hydrolysis product fluorescein. This is particularly problematic for flow cytoenzymology (FCE), where fluorescence is measured in individual cells allowing identification of subpopulations differing in esterase activity and/or membrane characteristics. We present a comparison of FDA with two potentially improved substrate probes for FCE, carboxyfluorescein diacetate (CFDA) and bis(carboxyethyl)-carboxyfluorescein-tetra acetoxy methyl ester (BCECF-AM). Substrates were characterized in terms of reaction and product efflux kinetics in EMT6 mouse mammary tumour cells, together with inhibition kinetics for the carbamoylating agent BCNU. Intact viable cells were analysed by FCE and spectrofluorimetry, and the latter was also used for cell sonicates and purified esterase. CFDA and BCECF-AM enter cells and are hydrolysed more slowly than FDA. CFDA and FDA hydrolyses obey Michaelis-Menten kinetics with Km values of around 19 and 2 microM, respectively, whereas BCECF-AM hydrolysis deviates from this classical behaviour. BCNU (5 X 10(-4) M) inhibits FDA and BCECF-AM hydrolyses by approximately 50%, compared to 30% for CFDA. CFDA may be partly hydrolysed by membrane-bound esterases. Efflux half-lives were 16 min, 94 min and greater than 2 h for products of FDA, CFDA and BCECF-AM, respectively. We conclude that BCECF-AM is the optimal substrate probe for FCE. This study emphasizes the need to optimize various parameters when selecting a substrate for flow cytoenzymological assay or when loading other reporter fluorochromes into cells via lipophilic esters.

Animals↗