Autofluorescence of the porcine endometrium during early pregnancy

Uteri recovered from cyclic gilts (n = 5) on Days 15-19 and pregnant animals (n = 34) on Days 13-40 were opened and examined under UV light. A line of greenish fluorescence was present in the mesometrial region in contact with embryonic membranes at Day 13. Small patches of reddish fluorescence subsequently appeared on the uterine mucosa near the embryonic disc, and these increased in intensity and size until they encompassed the entire area of contact between each conceptus and the endometrium, for lengths of about 20 cm, by Day 29. Fluorescence then diminished gradually and was almost totally absent by Day 40. Three additional gilts were unilaterally hysterectomized on Day 15 and treated with Evans blue dye 10 min before removal of the second uterine horn. Both horns were opened and compared under UV light, but no difference in the pattern of fluorescence could be detected. All fluorescence was associated with uterine rather than conceptus tissues. The occurrence of autofluorescence in uteri of pregnant pigs precludes use of Evans blue dye as an indicator of vascular permeability.

Evans blue treatment promotes blastomere separation and twinning in Lytechinus pictus embryos

Demembraned Lytechinus pictus embryos briefly treated with the dye Evans Blue during the first cleavage division subsequently showed frequent blastomere disengagement leading to development of twinned embryos. Further development of twinned embryos was observed in hanging drops and in batch cultures. The timing of micromere production was disturbed in some twinned embryos, but this disturbance was not correlated with subsequent developmental problems. Many twinned embryos resulting from blastomere separation following Evans Blue treatment developed into small but normal-appearing plutei.

Differential inhibition of various deoxyribonucleic acid polymerases by Evans blue and aurintricarboxylic acid

The inhibitory effects of two anionic compounds, Evans blue and aurintricarboxylic acid (ATA), on various kinds of polynucleotide-synthesizing enzymes were examined. Under the assay conditions, optimized for each enzyme species, both these compounds strongly inhibited the activities of the purified human DNA polymerases alpha, beta, gamma, and DNA primase as well as those of DNA polymerase I and RNA polymerase from Escherichia coli and Rauscher leukemia virus reverse transcriptase. ATA was particularly effective in inhibiting retroviral reverse transcriptase and cellular DNA polymerase alpha. Evans blue, which is a structural analogue of suramin, exerted its inhibitory action largely by competing with the template.primer for the same binding site of the enzyme. On the other hand, ATA inhibited most, if not all, of these enzyme activities noncompetitively with respect to either the template.primers or nucleoside 5'-triphosphate substrates. The inhibition constants for ATA were, in general, smaller than those for Evans blue.

Laser-induced endothelial damage inhibits endothelium-dependent relaxation in the cerebral microcirculation of the mouse

This study demonstrates endothelium-dependent relaxation in the surface arterioles of the brain. A helium-neon laser was used to injure endothelium in situ following i.v. injection of Evans blue dye, which sensitizes the bed to the laser. Areas 18 or 36 micron in diameter were injured and no longer relaxed to either 1 ml of acetylcholine chloride or bradykinin triacetate, 80 micrograms/ml delivered for 60 seconds. Dilations to sodium nitroprusside (30 micrograms/ml) were unaffected. Normal responses to nitroprusside, plus electron microscopy, established that vascular smooth muscle was uninjured. Endothelium-dependent relaxation was impaired when only minor ultrastructural damage was present. Dilation was inhibited downstream and upstream as far as 80 micron from the center of the laser beam. This suggests a spread of endothelium injury around the site of laser impact. However, inhibition was somewhat more marked downstream than upstream, implying that a portion of the downstream response was dependent on a substance released from an upstream site. To date, very few studies have reported endothelium-dependent relaxation in vivo, especially in the microcirculation. The present study accomplishes this. Moreover, in contrast to in vitro observations of endothelium-dependent relaxation in large vessels, the in vivo elimination of endothelium-dependent relaxation in the microcirculation required neither removal of endothelium nor injury to large numbers of endothelium cells. Since endothelium-dependent relaxation in the microcirculation has now been demonstrated using three different techniques to injure endothelium, it is reasonable to conclude that the phenomenon is real.

Aurintricarboxylic acid and Evans Blue represent two different classes of anionic compounds which selectively inhibit the cytopathogenicity of human T-cell lymphotropic virus type III/lymphadenopathy-associated virus

Aurintricarboxylic acid, an anionic triphenylmethane dye, and Evans Blue, an anionic compound structurally related to suramin, are, like suramin itself, inhibitors of human T-cell lymphotropic virus type III (HTLV-III)/-lymphadenopathy-associated virus (LAV) in vitro. These compounds may be targeted, at least in part, at the HTLV-III/LAV reverse transcriptase. The lack of any appreciable cytostatic action of aurintricarboxylic acid, Evans Blue and suramin against several murine and human cell lines, their inability to inhibit cellular DNA, RNA and protein synthesis, and their high lethal dose-50 (greater than or equal to 0.340 g/kg) for NMRI mice point to the selectivity of the compounds as inhibitors of HTLV-III/LAV.

Comparative inhibitory effects of suramin and other selected compounds on the infectivity and replication of human T-cell lymphotropic virus (HTLV-III)/lymphadenopathy-associated virus (LAV)

Suramin and various other selected compounds were evaluated for their in vitro inhibitory effects on the infectivity and replication of human T-cell lymphotropic virus (HTLV/III)/lymphadenopathy-associated virus (LAV). As parameters for infectivity and replication, respectively, we followed the cytopathic effect of HTLV-III/LAV on ATH 8 cells, a T-cell clone with high susceptibility to HTLV-III/LAV, and the expression of HTLV-III/LAV p24 gag protein in H9 cells infected with HTLV-III/LAV. As the most effective inhibitors of HTLV-III/LAV the following substances emerged (in order of decreasing activity): Evans Blue approximately equal to suramin greater than phosphonoformic acid greater than Direct Yellow 50. Several purine nucleoside analogues including vidarabine, tubercidin, neplanocin A, dihydroxypropyladenine, pyrazofurin and ribavirin were not inhibitory to HTLV-III/LAV. In our test systems, involving a high multiplicity of infection, HPA-23, previously reported to be effective against LAV reverse transcriptase, showed no inhibitory effect on HTLV-III/LAV infectivity for ATH 8 cells and proved only weakly inhibitory to HTLV-III/LAV replication in H9 cells. Thus, among the anionic dyes that are structurally related to suramin, compounds were found which were as active as suramin itself, if not more so.

[Evans blue as an adjuvant for enhancing delayed hypersensitivity in an experiment]

A modified method has been elaborated for induction of delayed type hypersensitivity (DH) in CBA mice with the use of Evans blue (EB) as adjuvant. This model permitted studying the mechanism of DH development, establishing the dependence of DH on the dose of EB, the dose and type of protein antigen, and realizing passive transfer of DH with the aid of splenocytes from active-synthesized mice. EB is a convenient and effective adjuvant for induction and study of the mechanism of DH development.

The synthesis of 5S RNA and transfer RNA in sea urchin embryos animalized by Evans blue

Animalization (ectodermalization) of embryos of Arbacia punctulata was induced by continuous treatment from the 2-cell stage with Evans Blue. Quantitative measurements of rates of accumulation of 5S RNA and tRNA in mesenchyme blastulae, in plutei and in corresponding animalized embryos showed that these rates per embryo and per cell were similar in control and in animalized embryos. The alterations in normal cell interactions and germ layer formation induced by Evans Blue did not affect the synthesis of 5S RNA and tRNA in sea urchin embryos.

Morphogenetic effects of evans blue and of zinc ions in embryos of Lytechinus variegatus

Morphogenetic effects of evans blue and of Zn++ in Lytechinus variegatus embryos are described. Viable unhatched maximally-animalized embryos were induced with 4.2 X 10(-5) M evans blue and with 4-8 X 10(-4) M ZnCl2. Hatching inhibition was reversed only with ZnCl2 suggesting that Zn++ is the preferred animalizing agent in this sea urchin species.

Influence of chronic hypertension on injured and uninjured arteries in spontaneously hypertensive rats

The influence of chronic essential hypertension in spontaneously hypertensive rats (SHR) on uninjured and deendothelialized arteries was investigated in two models of arterial endothelial injury (aortic balloon and carotid air injury). SHR rendered normotensive with antihypertensive medication (hydralazine, reserpine, and furosemide), normotensive Wistar rats, and Wistar rats treated with antihypertensive drugs served as controls. In uninjured vessels, slight intimal thickening and marked medial thickening were found in SHR but not controls. In injured vessels, endothelial regeneration was similar in SHR and controls. Intimal thickening due to smooth muscle cell proliferation was markedly enhanced in SHR compared to drug-treated SHR, whereas medial thickening in the injured vessels of SHR did not change over the time interval studied. Administration of drug to normotensive Wistar rats did not affect myointimal or medial thickening. These results indicate that acute arterial endothelial injury in chronically hypertensive rats produces marked myointimal thickening that can be controlled with antihypertensive medication.

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.

Evans blue: a specific inhibitor of factor VIII-induced platelet agglutination

Low concentrations of Evans Blue (less than 1 muM) inhibit the agglutination of formalin-treated platelets by bovine Factor VIII or by human Factor VIII in the presence of the antibiotic ristocetin. Evans Blue is a specific inhibitor of this reaction and acts by inhibiting the binding of Factor VIII to the platelet surface.

[Study on the inhibition of testicular polyadenylate polymerase stimulated by manganese]

Many different types of naturally occurring substances and of drugs were examined as potential inhibitors of a Mn++-stimulated and poly(A)-primed polyadenylate polymerase that was partially purified from rat testis. By far the most active inhibitors were anionic dyes that were either of the diazo naphthyl sulfonate category, such as Evans Blue, or were halogenated derivatives of fluorescein, like Rose Bengal. The characteristics of these in vitro inhibitions, which did not involve any photo-sensitized reactions, were examined in considerable detail.