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At least 19 recordsLinked to original sources
PubMed1980

Localization and neurophysiological properties of motoneurones of the M. triceps surae of the rat after retrograde labelling with Evans blue.

Evans blue was injected into either the medial and lateral gastrocnemius or the soleus muscle of adult albino rats to mark retrogradely the corresponding motoneurones in the spinal cord. The labelled motoneurones were identified by the red fluorescence of their perikarya in the ventral horn of segments L4--L6. In addition, a monosynaptic reflex action potential was recorded only in the ventral roots L4--L6 after stimulation of the nerves to the medial and lateral gastrocnemius and the soleus muscle. Excitability and reflex latencies of labelled and unlabelled motoneurones of segment L4--L6 as well as the conduction velocities of their axons were measured. Apart from a small but statistically nonsignificant increase in excitability, no functional differences were found between labelled and control neurones. Thus, retrograde labelling of motoneurones with Evans blue prior to performing electrophysiological experiments has the advantage that the marked motoneurones can be identified under the fluorescence microscope without the need of additional staining or fixation.

Action Potentials↗
PubMed1969

Promotion of the autolysis of alpha-chymotrypsin by Evans blue.

Evans blue has been demonstrated to promote the autolysis of alpha-chymotrypsin at low dye-to-protein ratios in alkaline solution. This effect has been attributed to the stabilization of less tightly folded conformers of the protein by the dye. The effect is specific. Of 20 other strongly acidic dyes tested, only trypan red showed activity comparable to that of Evans blue. A general discussion of the influence of ligand binding on the stability of proteins is presented.

Autolysis↗
PubMed1982

Suppression of tuberculoimmunity in mice by Evans blue dye.

Evans blue dye, which acts as an adjuvant in mice to promote induction of cell-mediated immunity, was found earlier to apparently act contrarily and decrease tuberculoimmunity. This phenomenon was investigated here in a long-term experiment examining the persistence of the suppressed immunity. Systemic suppression after injection of only 1 mg of dye was confirmed and was found to last for more than 2 weeks but less than 11 weeks. Localized evidence for dye-caused depression of tuberculoimmunity also was seen by the development in dye-injected mice immunized with emulsified whole bacilli of caseating tubercles at sites of pulmonary infection, a very rare type of pathology for tuberculosis in mice. The experiment, in addition, detected an aging-related decline in mice of resistance to tuberculosis evident by shortened survival, enlarged pulmonary tubercles, and increased susceptibility to systemic tuberculin reaction.

Aging↗
PubMed1996

P2-purinoceptor antagonists: II. Blockade of P2-purinoceptor subtypes and ecto-nucleotidases by compounds related to Evans blue and trypan blue.

Effects of Evans blue and four derivatives as well as of trypan blue and four derivatives, mostly smaller fragments but two compounds with an additional ethylene bridge in the center of the molecule, were studied on contractions of the rat vas deferens elicited by alpha, beta-methylene ATP (alpha, beta-MeATP; mediated by P2X-purinoceptors), relaxations of the carbachol-precontracted guinea-pig taenia coli elicited by adenosine 5'-O-(2-thiodiphosphate) (ADP beta S; mediated by P2Y-purinoceptors), and the degradation of ATP by rat vas deferens tissue. All compounds shifted the concentration-response curve of alpha, beta-MeATP in the rat vas deferens to the right, and most compounds increased the maximum of the curve. Each member of the Evans blue series was similar in potency to the corresponding member of the trypan blue series. Where three concentrations were tested, the Arunlakshana-Schild regression was linear, and the slope did not differ from 1. The apparent Kd values were between 0.8 and 385 microM. In the guinea-pig taenia coli, only the members of the trypan blue group were relatively potent, shifting the concentration-response curve of ADP beta S to the right in a surmountable manner. In 2 of 3 cases where three concentrations were tested, the slope of the Arunlakshana-Schild regression was lower than 1. Apparent Kd values in the trypan blue group were between 5.2 and 324 microM. The removal of ATP from the medium by vas deferens tissue was decreased mainly by the members of the Evans blue group, with IC25% values between 13 and 158 (in 1 case > 1000) microM. The results indicate that the position of the sulphonate residues at the terminal naphthalene rings of these compounds hardly influences P2X purinoceptor affinity but greatly influences P2Y affinity and ecto-nucleotidase blockade. Among active compounds, apparent purinoceptor affinity and ecto-nucleotidase blockade increase with the size of the molecules up to Evans blue and trypan blue themselves; introduction of a central ethylene bridge does not result in a further gain in potency. NH01, the desmethyl derivative of Evans blue, seems to be interesting because it is the compound with the highest P2X- versus P2Y-selectivity presently available.

Adenosine Diphosphate↗
PubMed1995

Functional consequences of inhibition of nucleotide breakdown in rat vas deferens: a study with Evans blue.

The effect of Evans blue on nucleotide breakdown, nucleotide-evoked contractions and electrically evoked contractions, overflow of ATP and overflow of tritium (after labelling with [3H]-noradrenaline) was studied in rat vas deferens. Pieces of vas deferens degraded 83 to 85% of added ATP, ADP and 2-methyl-thio ATP (all 100 microM) over 30 min. Evans blue (100 microM) reduced this degradation to 22 to 26%. Nucleotides elicited contraction with potency declining in the order alpha,beta-methylene ATP > 2-methylthio ATP > ATP > ADP. Evans blue (100 microM) shifted the concentration-response curve of alpha, beta-methylene ATP to the right and increased the maximum. Concentration-response curves of ATP, ADP and 2-methylthio ATP, in contrast, were shifted to the left and responses were much potentiated. In the presence of Evans blue, the rank order of potency was ATP > 2-methylthio ATP > alpha, beta-methylene ATP > ADP. Electrical field stimulation (100 pulses at 10 Hz) elicited contraction and an overflow of tritium and ATP. Evans blue (100 microM) did not alter the contraction and the evoked overflow of tritium but increased 24-fold the evoked overflow of ATP. The results indicate that Evans blue may serve as an-albeit impure-ecto-nucleotidase inhibitor in functional experiments. Such experiments demonstrate that the low potency of ATP (and also ADP and 2-methylthio ATP) in eliciting contraction, and the small size of the overflow of ATP upon sympathetic nerve stimulation, are due to rapid breakdown.

Adenosine Triphosphate↗
PubMed1995

Visualization of dystrophic muscle fibers in mdx mouse by vital staining with Evans blue: evidence of apoptosis in dystrophin-deficient muscle.

Degenerating muscle fibers in the skeletal muscle of mdx mice were visualized by vital staining with Evans blue. Evans blue injected intravenously stained only degenerating muscle fibers which were visible as blue fibers macroscopically and could also be seen as red fluorescent fibers microscopically. Evans blue-stained muscle fibers were either hypercontracted or degrading. Intact or regenerating muscle fibers in mdx mice and muscle fibers in B10 control mice were not stained with the dye. DNA isolated from Evans blue-stained fibers exhibited fragmentation to approximately 180 base pairs on agarose gel electrophoresis. Such DNA fragmentation was not found in DNA from unstained muscle fibers in mdx or B10 mice. Terminal deoxynucleotidyl transferase (TdT)-mediated dUTP nick end-labeling (TUNEL)-positive myonuclei were also found in Evans blue-stained muscle fibers but not in unstained ones. These results indicate that degenerating muscle fibers in the mdx mouse show an increase in membrane permeability and undergo apoptosis. Vital staining with Evans blue is useful not only for distinguishing degenerating muscle fibers, but also for studying the degeneration process biochemically in dystrophin-deficient muscle. This method may also be useful for evaluating the therapeutic effects of drug administration, gene transfer, and myoblast transfer in the mdx mouse.

Animals↗
PubMed1977

Plasma volume estimation in severely ill infants and children using a simplified Evans blue method.

Plasma volume was measured using Evans blue dye and 125iodinated human serum albumin (RIHSA) simultaneously in order to evaluate the accuracy of a simplified Evans blue method recommended by Nielsen and Nielsen (1962). 9 studies were performed in 8 newborn infants weighing 1.07 to 2.85 kg and 16 studies in 14 patients aged 6 months to 14 years suffering from severe circulatory disturbances. In 20 studies, plasma volumes measured by Evans blue and by RIHSA agreed within +/-5%, and in all the studies within +/-10%. The Evans blue method yielded higher plasma volumes than the RIHSA method in 19 instances. The mean difference (paired t-test) was only significant in newborn infants (+4.0+/-3.6%; P less than 0.05). The disappearance rates of Evans blue exceeded that of RIHSA in 16 studies, but this was only significant in the patients older than 6 months (+2.3+/-4.2%/h; P less than 0.05).

Adolescent↗
PubMed2001

Sensitive blood-retinal barrier breakdown quantitation using Evans blue.

PURPOSE: This study investigated whether a nonradioactive dye, Evans blue, can be adapted as a safe alternative to the isotope-dilution method for quantitating blood-retinal barrier breakdown. METHODS: Blood-retinal barrier breakdown was induced in rats with vascular endothelial growth factor (VEGF) or through the induction of diabetes. After allowing Evans blue to circulate in the vasculature, the dye was cleared from the bloodstream with saline, citrate, or citrate-buffered paraformaldehyde, and the efficacies of the perfusion solutions were compared. Extravasated dye was detected at 620 nm and was normalized against the time-averaged Evans blue plasma concentration, the circulation time, and also against wet and dry retina weights. RESULTS: Evans blue leakage from retinas treated with VEGF was 4.0-fold higher than that of contralateral untreated eyes (n = 6 rats, P: < 0.05). Retinal Evans blue leakage of eyes from 1-week diabetic animals (n = 11 retinas) was 1.7-fold higher (P: < 0.05) than that of nondiabetic controls (n = 10 retinas). Intra-animal, inter-retina weights showed significantly less variability (P: < 0.05) with the use of dry weights (11.2%, n = 74 retina pairs) than with wet weights (20.5%, n = 93 retina pairs). CONCLUSIONS: The Evans blue dye technique can be modified to be as sensitive and quantitative as the isotope-dilution method for measuring blood-retinal barrier breakdown. The advantages of the Evans blue technique are its safety, relative simplicity, and economy.

Animals↗
PubMed1993

Proconvulsant and anticonvulsant effects of Evans blue dye in rodents.

The effect of i.c.v. administration of Evans blue to sound sensitive DBA/2 mice and to genetically epilepsy-prone rats was studied. In mice, Evans blue (3.3-52 nmol) induced: hyperlocomotion, wild running, scratching, clonic muscle spasms, tonic seizure (latency 10-45 min), followed by death or recovery. The CD50 value for clonic seizures for Evans blue was 35(23-53) nmol. Pretreatment (45 min) with Evans blue (13-52 nmol, i.c.v.) dose-dependently reduced the incidence of sound-induced seizures in DBA/2 mice (ED50 value against clonic seizures = 30 [15-58] nmol, i.c.v). In rats, Evans blue (104 nmol, i.c.v.) induced electroencephalographic seizures in the hippocampus and cortex and behavioural limbic seizures with a latency of 15-20 min. A reduction in the mean score (from 5 to 2-3) for behavioural seizures was observed which lasted for 4-5 days in rats electrically-kindled daily in the hippocampal CA3 subsector. Sound-induced clonic seizures in kindled and non-kindled rats were reduced for 3-4 days after administration of Evans blue (104 nmol, i.c.v.).

Acoustic Stimulation↗
PubMed1986

Differential inhibitory effects of Evans blue on various DNA polymerases.

Evans Blue, an anionic dye which has been found to inhibit the replication of human immunodeficiency virus, proved also inhibitory to the DNA polymerases alpha and beta. The mode of inhibition was competitive with respect to the template X primer, and noncompetitive with respect to the deoxynucleoside triphosphate substrates. The inhibitory effect of Evans Blue on DNA polymerases is discussed in relation to that of suramin.

Azo Compounds↗
PubMed1993

Evans blue blocks P2X-purinoceptors in rat vas deferens.

In rat vas deferens, Evans blue 100 microM increased contractions elicited by high K+ and by noradrenaline but markedly reduced contractions elicited by the P2X-purinoceptor-selective agonist alpha,beta-methylene ATP (3 microM). The concentration-response curve of alpha,beta-methylene ATP was shifted to the right by Evans blue 30 microM and the maximal contraction was increased. In tissues incubated with nifedipine 10 microM, Evans blue 100 microM tended to increase the residual contraction elicited by noradrenaline and abolished the residual response to alpha, beta-methylene ATP (3 microM). The concentration-response curve of alpha,beta-methylene ATP was progressively shifted to the right by increasing concentrations of Evans blue in the presence of nifedipine; maximal contractions were increased by Evans blue 10 and 30 but not 100 microM. From the shifts to the right caused by Evans blue 30 microM, apparent pKB values of 5.9 (no nifedipine) and 6.0 (nifedipine present) were calculated. It is concluded that Evans blue blocks P2X-purinoceptors in rat vas deferens and in addition causes a non-receptor-specific enhancement of contractions.

Adenosine Triphosphate↗
PubMed1982

Binding properties of circulating Evans blue in rabbits as determined by disc electrophoresis.

Following injections of Evans blue (1-200 mg/kg) into rabbits, polyacrylamide gel disc electrophoresis showed that Evans blue binds to two protein fractions. The greater part was bound to albumin and the remainder to a plasma protein in the postalbumin fraction. Unbound Evans blue was present in each plasma sample analyzed. Attempts to liberate the dye from the coloured areas of the aorta and common carotid arteries by tissue electrophoresis failed unless very high concentrations of Evans blue were used. This indicates that at the concentrations used by many investigators areas dyed by Evans blue may not be equated with the presence of diffusible protein-dye complexes.

Animals↗
PubMed1980

Distribution of albumin in the normal monkey eye as revealed by Evans blue fluorescence microscopy.

Since intravenously injected Evans blue binds irreversibly to serum albumin, its distribution reflects albumin exchange between the intravascular and extravascular tissue compartments. In histologic specimens examined by fluorescence, microscopy, extravasated Evans blue--albumin complex was identified within the ciliary body and trabecular meshwork of normal monkey eyes. In eyes fixed by intra-arterial perfusion of fixative, no dye was identified in the choroid, retina, or optic nerve. With immersion fixation, however, some extravasation was seen in the choroid and adjacent optic nerve. In some specimens, the optic nerve was stained not only with material apparently leaking from the choroid but also from a breakdown of the blood-brain barrier in the major disc vasculature during the interval before fixative penetrates into the tissue. Perfusion fixation must be used to avoid this artifact, and freezing techniques would be even better.

Animals↗
PubMed1988

The effects of steroidal and nonsteroidal anti-inflammatory agents on uptake of Evans blue in experimental metastasis.

The effects of anti-inflammatory drugs on uptake of Evans blue were studied in solitary Walker carcinosarcomas implanted in the livers of Sprague-Dawley rats. Animals were sacrificed at 5 min, 30 min, and 6 hr after administration of the anti-inflammatory drugs and Evans blue, and spectrophotometric measurements of the Evans blue in tumor and normal liver tissue were carried out. Uptake of Evans blue in the tumors was significantly decreased at all time periods after the injection of the following, as compared to controls: steroids (cortisol, methylprednisolone, and triamcinolone), the antihistamine diphenhydramine, and nonsteroidal anti-inflammatory agents (naproxen, ibuprofen, indomethacin, and phenylbutazone). The effects of these drugs on uptake of Evans blue in the normal liver were more variable.

Animals↗
PubMed1983

Evans blue fluorescence: quantitative and morphological evaluation of vascular permeability in animal tissues.

The dye Evans blue was used to monitor vascular protein leakage. Fluorometric measurement of Evans blue in formamide extracts of rat tracheal tissue was performed after induction of protein leakage by electrical vagus nerve stimulation and compared with the widely used colorimetric detection. The fluorescence method was approximately 100 X more sensitive than the colorimetric method. Furthermore, Evans blue fluorescence (excitation at 620 nm, emission at 680 nm) was used for microscopic investigation of cryostat sections of tracheal tissue. Extravasated Evans blue after electrical nerve stimulation was mainly found in the subepithelial layer of the trachea obviously bound to tissue constituents. It is suggested that Evans blue fluorescence can be applied for quantification of protein leakage with high sensitivity which opens the possibility of measuring this reaction in very small regions with high accuracy, as well as for tissue localization of protein leakage at the microscopic level.

Animals↗