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At least 19 recordsLinked to original sources
PubMed1978

Abrogation of tumor rejection by trypan blue.

Trypan blue treatment prevented tumor-specific rejection in three animal model systems. These included the spontaneous rejection of tumors of mice (UVT-2051) and guinea pig (line 1 hepatoma) as well as vaccine-induced rejection of a guinea pig tumor (line 10 hepatoma). Secondary immune reactions to line 10 cell challenges were not abolished by trypan blue treatment. Although trypan blue is a potent inhibitor of macrophage cytotoxicity in vitro, the mechanism by which it inhibited tumor-specific rejection has not been established.

Animals↗
PubMed1991

Effect of Evans blue and trypan blue on syncytia formation and infectivity of human immunodeficiency virus type I and type II in vitro.

Polyanionic compounds were used to inhibit infectivity of human immunodeficiency virus in vitro. Suramin, Evans blue, and Trypan blue were shown to inhibit syncytia formation normally observed when HIV-1-infected cells are cocultured with CD4+ cells. The inhibition was more pronounced with Evans blue than with any of the other polyanions studied. The inhibitory effect was significantly weaker in HIV-2 systems. However, the reverse transcriptase activities of both types of viruses were inhibited by Evans blue. Another polyanionic compound, phosphorothioate 28-mer cytidine homopolymer (SdC28) was shown to inhibit syncytium formation induced by HIV-1-and HIV-2-infected cells in an identical manner. Evans blue showed partial blocking of gp120 binding to CD4 in a solid-phase enzyme-linked immunosorbent assay (ELISA). These results suggest that the polyanionic dyes may exert their antiviral effects, at least in part, by interfering with the binding and fusion of HIV with susceptible T cells.

Antiviral Agents↗
PubMed1979

Direct effects of trypan blue on thyroid secretion.

Trypan blue directly inhibited in vitro thyroid secretion (butanol soluble 125I release to the media) induced by both thyroid stimulating hormone (TSH) and dibutyryl cAMP. Intracellular colloid droplet counts were also decreased. Inhibition was directly proportional to dye concentration and could be overcome by supramaximal TSH and dibutyryl cAMP. Inhibition could be observed as early as 20 min of incubation, was not increased by preincubation, and could even be demonstrated after TSH in vivo. Trypan blue, in vivo, produced similar inhibition of thyroid secretion. Incubation of 125I-thyroglobulin with lysosomal enzymes revealed inhibition with much lower concentrations of dye. Inhibition of lysosomal enzyme(s) would not appear to explain the marked decreases in colloid droplets, and this may represent two separate effects of trypan blue on thyroid secretion.

Animals↗
PubMed1977

Direct effects of trypan blue on cardiac extracellular macromolecule synthesis.

The direct effects of the cardiac teratogen trypan blue on some parameters of embryonic chick heart metabolism were examined in vitro. Trypan blue inhibits chondroitin sulfate biosynthesis but stimulates incorporation of 3H-glucosamine into hyaluronate, heparin, and glycopeptides. 3H-fucose incorporation into glycoprotein is also stimulated. Total incorporation of 14C-labeled amino acids is elevated in the presence of trypan blue. Trypan blue does not cause qualitative changes in labeled end products; rather the metabolic alterations are quantitative. The possible exceptions are glucosamine-labeled glycoproteins since quantitative differences in glycopeptides could reflect qualitative differences in parent glycoproteins. These observations suggest that abnormal heart development, induced by trypan blue, may result from a multiplicity of metabolic alterations and not from any single chemical change.

Animals↗
PubMed1977

Effects of trypan blue treatment on the immune responses of mice.

It has been reported that trypan blue treatment decreases the nonspecific resistance of mice to transplanted tumors and inhibits the in vitro cytotoxic activity of activated macrophages. We wished to determine whether this effect of trypan blue could be due to a selective inhibition of certain macrophage functions or whether it reflected a broader form of immunosuppression. We therefore tested the effects of trypan blue on a variety of immunological responses. Treatment of mice with trypan blue delayed their rejection of skin allografts and transplants of a highly antigenic syngeneic ultraviolet light-induced tumor. Trypan blue treatment of either donor or recipient decreased the local graft-versus-host reaction. Filtration of lymph node cells from trypan blue-treated donors on a nylon wool column before use in the graft-versus-host assay abrogated the depressive effect of trypan blue. A transient reduction in the blastogenic response of spleen cells to concanavalin A and lipopolysaccharide mitogens was observed after a single injection of trypan blue, but the response of lymph node cells was unaffected. The depressed response of splenic lymphocytes was not entirely reversed by removal of adherent cells. The primary and secondary hemagglutinin responses to sheep erythrocytes were unaffected in trypan blue-treated mice, and the proportion and phagocytic activity of thioglycolate-induced peritoneal macrophages were also unaltered. We conclude that treatment of mice with trypan blue selectively inhibits certain macrophage functions but, at high doses, it can also inhibit some lymphocyte activities.

Agglutinins↗
PubMed1978

Trypan blue inhibits complement-mediated phagocytosis by human polymorphonuclear leukocytes.

Trypan blue completely inhibited attachment of human polymorphonuclear leukocytes (PMN) to Sepharose beads coated with C3 ant to sheep erythrocytes coated with IgM plus C3, but it did not inhibit attachment to erythrocytes coated with IgG. These results suggested that trypan blue inhibited C-mediated attachment to PMN membranes. Corroborative studies were performed with a strain of Staphylococcus aureus that requires C but not antibody, for opsonization and that activates the alternative pathway. Trypan blue was not toxic to PMN or bacteria, did nto interfere with immunoglobulin or C interactions, and did not affect attachment of opsonins to bacteria. However, the dye impaired PMN killing of S. aureus in normal nonimmune serum by inhibiting bacterial attachment to and ingestion by PMN. Further evidence that the inhibition was at the C3 receptor level came from the observations that, 1) once staphylococci were attached to PMN at either 37 degrees C or 0 degrees C, addition of trypan blue did not inhibit killing; and 2) trypan blue inhibited killing of bacteria opsonized with serum sufficient in C but previously absorbed at 0 degrees C with the same strain of organism to deplete specific antibody. Further studies with this agent may elucidate the roles of opsonic receptors on human phagocytes.

Cell Adhesion↗
PubMed1975

Some additional observations relating to the mechanism of trypan blue induced teratogenesis.

The mechanism and site of teratogenic action of trypan blue on mammalian embryos was reinvestigated. The experiments to be presented include (1) an analysis of the effect of trypan blue treatment on the morphology of the early mouse egg cylinder, (2) a demonstration of the effect of dye treatment on the enzyme acid phosphatase of yolk sac epithelium using histochemical procedures. Results obtained from these experiments indicate that trypan blue injected into mothers on day 7 of gestational age leads, within 12 to 24 hours after treatment, to dramatic abnormalities in 90-95% of egg cylinders examined. The frequency of gross malformations obtained by this treatment is considerably less when litters are examined at later stages of gestation. Acid phosphatase activity in yolk sac epithelium is depressed by the dye treatment, but there is no difference between enzymatically depressed yolk sacs of malformed embryos and yolk sacs surrounding normally appearing litter mates both obtained from trypan blue treated mothers. The hypothesis that trypan blue may exert its teratogenic effect by the direct exposure of egg cylinder stages to the dye, and that some of the egg cylinders affected may subsequently repair, is recommended for further testing.

Abnormalities, Drug-Induced↗
PubMedDate not supplied

On the prenatal noxious effects of trypan blue and of a related azo dye.

Since 1948 trypan blue has been a well-known and extensively used experimental teratogen, belonging to the group of azo dyes. Chemically, trypan blue consists of a biphenyl molecule (0-tolidine or benzidine) combined by means of azo linkages with two molecules of a substituted naphthalene. Between 1987-89 the effect of the replacement of the biphenyl molecule by a molecule of p,p'-diaminobenzanilide upon the prenatal noxious action of trypan blue has been controlled. Investigations were carried out on three species: chick embryos, albino rats and albino mice. In the species used, the replacement annihilates the teratogenic properties of the dye, with the persistence of some embryotoxic effects. On the other hand, the control of o-tolidine and of p,p'-diaminobenzanilide revealed that no one had teratogenic properties (only some embryotoxic effect, more marked in the case of o-tolidine). It results that the teratogenic action of trypan blue cannot be attributed to the o-tolidine molecule proper but to an effect which results (in a for the moment unknown manner) from its combination with the other parts of the dye molecule.

Abnormalities, Drug-Induced↗
PubMed1989

[Trypan blue staining capacities of the culture cells (2)--The mechanism of staining].

The cultured cells dispersed by rubber policeman were stained with trypan blue, but these cells were viable at the meaning of keeping viral infective center forming capacity and at the meaning that trypan blue stained cells were transferred to unstained ones by trypsin treatment. This phenomenon may be important not to miscount numbers of the viable cells in cultured cells. Phagocytosis (endocytosis) is well known as a reaction inhibited by NaF or monoiodoacetate, but these metabolic inhibitors did not inhibit trypan blue staining of the cells dispersed both by rubber policeman and 0.05% trypsin treatment. The cells suspended in higher osmotic pressure media were more stainable with trypan blue than lower ones. Addition of K+ to the reaction mixture was not effective on trypan blue staining. These results suggest that "alive" cells dispersed by rubber policeman are stained with trypan blue not to utilize phagocytosis (endocytosis) or Na+-K+ pump, whose reactions couple with energy production. Trypan blue staining capacity of the cultured cells may be depended on pore sizes of protein channels (for example, fixed or gated transport protein channel) in lipid-bilayers of cell membranes. It is concluded that the cells dispersed by trypsin treatment (spherical shape in microscopical observation) and spherical cells in rubber policeman dispersing ones are unstained with trypan blue to contain smaller pore size channels in the cell membranes, but the rest, amoeba-like form cells dispersed by rubber policeman and dead cells are stained to contain larger ones.

Cell Survival↗
PubMed1977

Binding and uptake of trypan blue by developing oocytes of Locusta migratoria migratorioides.

Resorbing oocytes are heavily stained by trypan blue injected into the haemolymph; this serves as a basis for a quick and convenient method for measuring the degree of resorption. Oocytes in the beginning of their development are most susceptible towards resorptive tendencies. The uptake of trypan blue by normally developing oocytes is proportional to the oocyte surface. From 'double-marker' experiments, in which trypan blue is injected into the haemolymph together with [3H]inulin (which does not bind to the oocyte membrane) it is estimated that the contribution of binding in the interiorization of trypan blue is in the order of 80%, under the conditions given. In vitro incubations show the interaction of trypan blue with the membrane to be electrostatic in nature.

Animals↗
PubMed1979

Suppression of cell-mediated tumor cell lysis and complement-induced cytotoxicity by trypan blue.

Different forms of cell-mediated cytotoxicity were suppressed in the presence of trypan blue. The systems affected included lysis of antibody-coated tumor cells by normal and C. parvum-stimulated mouse peritoneal cells and lysis of allogeneic targets by immune effector cells. The inhibition, measured in a 4-hr 51Cr release assay, was reversible and did not occur in the presence of 30% fetal calf serum or albumin. Binding between effector and target cells through Fc receptors was not affected, and lysis of allogeneic cells was inhibited at the lytic step rather than at the binding step. In contrast, lysis of sensitized erythrocytes was not inhibited by trypan blue, suggesting that lysis of these targets may not involve the steps required in tumor cell lysis. Trypan blue blocked the function of antibody before binding to target cells and also suppressed complement-induced cytolysis. Most individual complement components were susceptible to the inhibitory action of trypan blue. These results reveal an affinity of trypan blue for proteins in general that may be responsible for many of its biologic actions.

Animals↗
PubMed1977

Permeability of inner and outer layers of rat and rabbit aortic wall. Two new microscopic test with trypan blue.

Two new permeability tests are described for use with intravenously injected trypan blue. One depends on the demonstration of trypan blue by its specific red fluorescence in green light at 570 nm, while the other is a surface microscopy technique at low magnification, using illumination from a fibre-optics light source. The routes of entry of the trypan blue-albumin complex into the rat and rabbit aorta appear to be from both the inner and outer surfaces. Over the period 1/4-24 h after injection of the dye, more entered from the outer surface than the inner surface in the rat aorta and rather more in the rabbit thoracic aorta. The arch of the rabbit aorta showed in general rather greater entry from the inner surface. Trypan blue that has entered the aortic wall is partly taken up by the elastic lamellae. Elastic competes successfully for the dye and captures it from the trypan blue-albumin complex; this uptake is blocked by deamination with nitrous acid.

Animals↗
PubMed1978

The induction of axial blisters in the chick embryo by trypan blue.

The hemorrhage, blister formation, and rumplessness observed in the chick embryo following treatment with trypan blue may be due to (1) increased ventricular blood pressure or (2) to necrosis and edema in the caudal region of the embryo by inhibiting nutrient utilization. To test the role of increased ventricular blood pressure in the induction of caudal blisters, primitive streak to 7-somite chick embryos were cut in half, separating the upper presumptive heart region from the lower presumptive trunk and tail regions. Each half was then explanted on media containing trypan blue for 24 hours. In intact embryos treated with 0.04 mM trypan blue the frequency of blisters in the posterior region was 80.8%. The blisters usually appeared on both sides of the neural tube, below or in the region of the last few somites. In transected embryos treated with trypan blue, the frequency of blisters in the posterior halves which had beating hearts was 2.6%. However, the frequency of blisters in the posterior halves which were not connected to beating hearts was 47.8%. In some cases the blisters were found in posterior halves in which the rump was not well developed or present at all. Thus, we may conclude that: (1) direct connection between the heart and the rump is not necessary for the induction of caudal blisters. (2) The presence of a well-differentiated rump is also not necessary for blister formation. We suggest that trypan blue acts directly on organs or structures found in the caudal region of the chick embryos.

Abnormalities, Drug-Induced↗
PubMed1977

Trypan blue: identification and teratogenic and oncogenic activities of its coloured constituents.

Three coloured substances frequently present as contaminants in commercial samples of trypan blue have been identified as those monoazo dyes in which 4-amino-3,3'-dimethyl-biphenyl, 4-amino-3,3'-dimethyl-4'-hydroxy-biphenyl or omicroc-tolidine are coupled to H-acid. These dyes have been synthesized and, together with purified samples of trypan blue, tested for teratogenic activity in mice and oncogenic activity in rats. Unpurified trypan blue was both teratogenic and oncogenic; purified trypan blue, was teratogenic but only weakly oncogenic; the monoazo dyes possessed neither activity. It is concluded that the main blue component of trypan blue is the teratogenic principle and that some as yet unidentified component of the purple fraction either is the main oncogenic principle or potentiates the action of the blue component.

Animals↗
PubMedDate not supplied

Trypan Blue as a marker of plasma membrane permeability in alloxan-treated mouse islet cells.

Suspensions of pancreatic islet cells from noninbred ob/ob-mice were incubated with Trypan Blue. Microscope photometry showed that apparently viable cells excluded the dye completely, whereas the nuclei of nonviable cells accumulated Trypan Blue by a saturable process. The nucleus-to-medium dye gradient was more then 30:1 in media containing 0.1% or less Trypan Blue. The apparent affinity constant for nuclear binding of the dye was 3.1 X 10(4)l/mol. Albumin partially inhibited the nuclear staining. More than 0.5% Trypan Blue in the medium was toxic per se. In the absence of albumin, 0.5 or 20 mmol/l alloxan, 1 mmol/l N-ethylmaleimide, or 0.1 mmol/l chloromercuribenzene-p-sulphonic acid, but not 20 mmol/l streptozotocin, increased the frequency of islet cells stained with 0.1% Trypan Blue. The absorbance of nuceli was also increased in cells treated with alloxan or N-ethylmaleimide, but not in those treated with chloromercuribenze-p-sulphonic acid. It is concluded that alloxan rapidly increases the permeability of the plasma membrane in mouse beta-cells. This action of alloxan appears to be more acute than any such effect of streptozotocin.

4-Chloromercuribenzenesulfonate↗
PubMed1977

Alloxan cytotoxicity in vitro. Microscope photometric analyses of Trypan Blue uptake by pancreatic islet cells in suspension.

Suspensions of islet cells were prepared by shaking pancreatic islets from non-inbred ob/ob mice in a Ca2+-free buffer. The cells were incubated with or without 20 mM-alloxan, and subsequently with Trypan Blue. The uptake of Trypan Blue by cell nuclei was analysed by microscope photometry and by counting the frequency of cells appearing stained on visual inspection. Cells classified as stained or unstained by inspection showed no overlap in nuclear absorbance. Suspensions not exposed to alloxan contained 70-80% of unstained cells. Alloxan markedly decreased the frequency of unstained cells, an effect counteracted by 5 or 20 mM-D-glucose. The spectrum of Trypan Blue in islet-cell nuclei was red-shifted by about 20 nm. A similar red-shift was observed on adding the dye to solutions of albumin or histones, but not on mixing the dye with DNA. Binding to basic proteins may explain the concentrative uptake of Trypan Blue in dead cells and contribute to the oncogenic transformation of phagocytotically active cells. Beta-Cells in vitro are killed by alloxan and hence represent a valid model for studying the diabetogenic action of the drug.

Albumins↗
PubMed1989

Trypan blue in vivo stains nigral dopaminergic neurons killed by 6-hydroxydopamine.

Dopaminergic neurons in the substantia nigra killed by 6-hydroxydopamine were stained in vivo by intracerebral injections of trypan blue. Such staining appeared specific for dead neurons, although a proportion of these retained the ability to stain with Nissl dyes for at least 2 days. Neurons retained trypan blue in vivo for periods of up to 9 days. Trypan blue staining of some neurons outside the substantia nigra demonstrated the use of this dye in determining the degree of non-specific toxicity of 6-hydroxydopamine. Twenty-four hours after infusion of trypan blue almost no background staining was present and individually stained neurons were clearly visible. Thus the use of trypan blue may have a general application as a sensitive method for estimating discrete areas of toxin-induced neuronal death, and for estimating the degree of specificity of a toxin.

Animals↗