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At least 73 records · Page 4Linked to original sources
PubMed2005

Production of superoxide radical in reductive metabolism of a synthetic food-coloring agent, indigocarmine, and related compounds.

Indigocarmine, which is widely used as a synthetic colouring agent for foods and cosmetics in many countries, was reduced to its leuco form and decolorized by rat liver microsomes with NADPH under anaerobic conditions. The reductase activity was enhanced in liver microsomes of phenobarbital-treated rats, and inhibited by diphenyliodonium chloride, a NADPH-cytochrome P450 reductase (P450 reductase) inhibitor, but was not inhibited by SKF 525-A or carbon monoxide. Indigocarmine reductase activity was exhibited by purified rat P450 reductase. In contrast, when indigocarmine was incubated with rat liver microsomes and NADPH under aerobic conditions, superoxide radical was produced and its production was inhibited by superoxide dismutase and diphenyliodonium chloride. When indigocarmine was incubated with purified rat P450 reductase in the presence of NADPH, superoxide radical production was enhanced 17.7-fold (similar to the enhancement of indigocarmine-reducing ability) as compared with that of rat liver microsomes. A decrease of one molecule of NADPH was accompanied with formation of about two molecules of superoxide radical. P450 reductase exhibited little reductase activity towards indigo and tetrabromoindigo, which also afforded little superoxide radical under aerobic conditions. These results indicate that indigocarmine is reduced by P450 reductase to its leuco form, and superoxide radical is produced by autoxidation of the leuco form, through a mechanism known as futile redox cycling.

Animals↗
PubMedDate not supplied

[Intraoperative diagnosis of retinal ruptures in rhegmatogenous retinal detachment in avitreous eyes by using a coloring agent].

Sixteen patients were operated for regmatogene retinal detachment developed at different time periods after a previously made vitrectomy; no retinal ruptures were found in preoperative examinations. The method of colouring with subretinal fluid, 0.1% fluorescence solution, was intraoperatively used for the detection of such ruptures. The coloured fluid escaped from the subretinal cavity through a retinal rapture into the vitreal cavity, which ensured an easy visualization of ruptures. Retinal ruptures could be detected in all 16 (100%) patients. They were located in 8 (50%) cases in the zone of previously made sclerotomy and were regarded as an outcome of the local proliferative vitreoretinopathy on the remains of the basic vitreous elements.

Female↗
PubMed2004

Factor analysis in both spatial and temporal domains of color blooming artifacts in ultrasound investigations utilizing contrast agents.

Color blooming artifacts can cause misinterpretations of normal and pathological structures during color Doppler flow imaging with ultrasound contrast agents (USCAs). These artifacts are characterized in both the spatial and temporal domains: in the spatial domain, artifacts result from wave propagation and the ultrasound system; and in the temporal domain, the color blooming time (CBT) is used to denote the duration of artifacts. In our experiments, CBT decreased from 86.7 to 46.8 s when the transmitting pressure was decreased from 370 to 180 kPa. From this, we conclude that an adaptive mechanical index can significantly shorten the CBT, which may in turn prolong the optimal viewing time during in vivo ultrasound investigations utilizing USCAs.

Artifacts↗
PubMed1975

Succinylsulfathiazole crystal forms. II: Effect of additives on kinetics of interconversion.

The effect of various additives on the rate of transformation of the metastable anhydrous succinylsulfathiazole Form I to the water-stable dihydrate Form II in aqueous suspensions was studied. Some structurally related compounds, viscosity-imparting agents, surfactants, and coloring agents were used as possible transformation retardants. The effect of including seeds of Form II in the presence and absence of additives is also discussed. Some additives, e.g., methylcellulose and phthalysulfathiazole, showed significant transformation-retarding effects. Other additives, e.g., sulfanilamide and glycerin, increased the rate of transformation. Coloring agents had only slight effects. Utilization of the results in the formulation of physically stable aqueous suspensions of succinylsulfathiazole is discussed.

Chemical Phenomena↗
PubMed1984

Additives in synthetic polymers: an overview.

The 14 major classes of additives in plastics, e.g., plasticizers, flame retardants, heat stabilizers, antioxidants, UV absorbers, foaming agents, initiators, lubricants, antistatic agents, curing agents, colorants, fillers and reinforcements, solvents, and optical brighteners were reviewed from a primary consideration of their structural chemical classes, areas of application as well as their production volumes and future use trends. The number of possible combinations of plastics additives that can be employed are staggering. In most cases, little is known of their toxicological properties and in many cases their identity is not commonly known. It should also be noted that many new additives of new generic types in each of the above classes are being developed and introduced into the market yearly as well as new technology in polymer production, e.g., increasing use of additive polymers for PVC.

Chemical Industry↗
PubMed2006

New detection method for hydrogen gas for screening hydrogen-producing microorganisms using water-soluble wilkinson's catalyst derivative.

A water-soluble color indicator was developed for the effective screening of hydrogen-producing microorganisms. This indicator consists of a coloring agent and a water-soluble derivative of Wilkinson's catalyst. Wilkinson's catalyst, Tris(triphenylphosphine) rhodium chloride, had been developed as a catalyst for the hydrogenation of olefins. We used a sulfonate of the catalyst for the hydrogenation of coloring agent in an aqueous medium. Several coloring agents, such as methyl orange, methyl red sodium, neutral red and Evan's blue, dissolved in water together with the sulfonated catalyst showed a change in color when hydrogen gas was fed into the solution by sparging at room temperature. We confirmed that methyl orange was decolorized by biologically produced hydrogen, when the photosynthetic bacterial strain Rhodobacter capsulatus ST-410 was grown in a medium containing 0.6 mM catalyst and 0.075 mM methyl orange in test tubes of 5 ml working volume.

Catalysis↗
PubMed1993

Echocontrast agent enhanced color flow imaging of the breast.

An ultrasound contrast agent which survives transit through the pulmonary circulation after injection into a peripheral vein can also be used for the demonstration of flow characteristics in the peripheral organs. Such a substance (SH U 508 A, Schering AG, Berlin) was tested in the Gynecological Department of the University of Marburg for its suitability for enhancing color-coded Doppler signals in mammary diagnosis in a group of ten women with breast tumors. The observations made are compared with the histologically confirmed diagnoses. The very distinct enhancement of the color-coded Doppler signals allows reliable demonstration of the vascularization characteristics, not only of the malignant, but also of all benign solid tumors examined. Color signals were even recorded from normal mammary tissue, which means that the demonstration of perfusion can no longer be used on its own as a diagnostic criterion. Observation of the characteristics of the blood supply to a tumor might, on the other hand, be an advantage, not only in respect of tumor typing, but also as regards the prognosis of a tumor. In this connection, the registration of the arrival, retention and wash-out phases specific to a contrast agent appears to furnish particularly interesting information about the growth dynamics of a tumor.

Journal Article↗
PubMed1991

Effects of laboratory disinfecting agents on color stability of denture acrylic resins.

This study determined the effects of chemical disinfecting agents on denture acrylic resins. Tested resins included the products CH Lucitone, Triad VLC, and Truliner. The disinfecting agents were sodium hypochlorite, Exspor, Cidex, and Wescodyne-D. Acrylic resin samples were placed in the various disinfecting agents and then evaluated for color changes at time intervals ranging from 15 minutes to 72 hours. No observable color change of any acrylic resin was seen before 2 hours. Both 1% sodium hypochlorite and 2% Cidex disinfectants produced the least discoloration of the acrylic resins, and Wescodyne-D disinfectant produced the most acrylic resin discoloration. Truliner resin discolored more than Triad VLC resin, and both underwent more color change than CH Lucitone resin. If manufacturers' recommended disinfecting times are followed, clinical and laboratory disinfection of acrylic resin dentures should cause no observable color change.

Acrylic Resins↗
PubMed1977

Influence of sunscreening agents on color stability of tablets coated with certified dyes III: FD&C Yellow No. 6.

The influence of a protective coating of six sunscreening agents (glyceryl p-aminobenzoate, benzocaine, cinoxate, homosalate, n-octyl salicylate, and amyl salicylate) upon the photostability of FD&C Yellow No. 6 used to color coat tablets was studied. The alcohol film, modified sugar-, and film-coating methods were used to apply the sunscreening agents. Tablets were exposed to 1000 foot-candles of light for various times, after which reflectance measurements and visual observations were recorded. FD&C Yellow No. 6 did not follow the Kubelka-Munk equation. The order of relative stability was FD&C Yellow No. 6 greater than erythrosine sodium (FD&C Red No. 3) greater than FD&C Blue No. 1. The greatest protection against fading was afforded by benzocaine.

Azo Compounds↗