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Results for “Quinaldines”

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PubMed2002

Fluorescent probing of the ligand-binding ability of blood plasma in the acute-phase response.

The acute-phase response alters the composition of carrier proteins in plasma, which may affect the blood deposition and transport of biomediators and drugs. The effect of the acute-phase response on the ligand binding ability of plasma was studied in leukemic children with and without systemic inflammation (sepsis and septic shock). To target different transport proteins, differentially charged fluorescent dyes were used: anionic ANS (8-anilinonaphthalene-1-sulfonate), uncharged Nile red, and cationic Quinaldine red. Human serum albumin was a principal carrier for ANS and competed for Nile red binding with lipoproteins. The synchro-scan fluorescence spectra of Nile red in plasma distinguished two species of the dye bound to serum albumin and to low-density and/or very low-density lipoproteins. The binding of Quinaldine red did not correlate with albumin and lipoprotein levels, and was probably determined by alpha(1)-acid glycoprotein. Compared with the control group, leukemia increased Quinaldine red binding by 65% and did not significantly affect the binding of other probes. Sepsis and septic shock did not change the binding of Quinaldine red, but progressively decreased ANS binding, finally by about 33%, and shifted Nile red distribution from serum albumin toward lipoproteins. These changes reflected a modified composition of the three principal transport proteins in plasma in the acute-phase response. Simple and rapid fluorescent tests developed in this study can be used to evaluate the acute-phase response and to optimize drug administration protocols in clinical practice.

Acute-Phase Reaction↗
PubMed2002

Effects of four anaesthetics on the innate immune response of gilthead seabream (Sparus aurata L.).

Anaesthesia may depress the immune system in mammals, but there is no available information on this topic in fish. In the present work, four anaesthetics that are used in aquaculture, MS222 (0 19 mM), benzocaine (0.21 mM), 2-phenoxyethanol (16 mM) and quinaldine sulphate (0.083 mM), were tested in order to observe their effects on the gilthead seabream (Sparus aurata L.) innate immune system. The results showed that the four anaesthetics produced increased blood glucose levels after an hour. In addition, benzocaine and 2-phenoxyethanol depressed complement activity and phagocytosis, while MS222 and quinaldine sulphate did not. Some anaesthesia is a common practice in aquaculture, the data obtained should be taken into account to avoid possible immunodepression in farmed fish.

Aminobenzoates↗
PubMed1978

[Occupational dermatitis due to a yellow quinophthalone dye (solvent yellow 33: C.I. 47 000)].

An occupational allergic contact dermatitis caused by a yellow quinophthalone dye which is used for colored smokes in detonators was the reason for further studies of this case of allergy. Solvent Yellow 33 (German: Rauchgelb) belongs to the groups of quinaldine dyes which are produced by condensing quinaldine and phthalic anhydride. The dye itself is a mixture of 67% unsubstituted quinophthalone and 33% 6-methylquinophthalone (Colour Index 47 000). Quinophthalone derivatives are widespread in technology and industry and are used as yellow dyes in food (pudding), plastics (PVC), textile goods (nylon) and cosmetics (lipsticks, make-up). Cases of contact sensitization due to quinophthalone dyes are seldom recognized. Sensitizing experiments in guinea pigs were unsuccessful. Therefore Solvent Yellow 33 must be considered a weak sensitizer.

Adult↗
PubMed1999

A robotics-based automated assay for inorganic and organic phosphates.

Phosphate analyses are fundamental to a broad range of biochemical applications involving inorganic phosphate and organic phosphoesters such as phospholipids, phosphorylated proteins, and nucleic acids. A practical automated method utilizing robotics is described in this report. Five colorimetric methods of phosphate analyses based on formation of a phosphomolybdate complex and compatible with the automated assay were tested, and the fundamental chemistry is discussed. The relative sensitivities are malachite green > crystal violet > quinaldine red > ascorbate reduction > antimony-modified ascorbate reduction, although only a fourfold improvement was observed in going from the modified ascorbate procedure to malachite green. Malachite green was selected to optimize the assay because this dye provided the highest sensitivity. However, where color stability and low blanks are more important than sensitivity, the ascorbate reduction and quinaldine red methods were found to be better choices than malachite green. Automation using a robotic liquid-handling system substantially reduces the labor required to process large arrays of samples. The result is a sensitive, nonradioactive assay of inorganic phosphate with high throughput. A digestion step in an acid-resistant 96-well plate was developed to extend the assay to phosphate esters. The robotic-based assay was demonstrated with inorganic phosphate and a common phospholipid, phosphatidylcholine.

Automation↗
PubMed2000

Characterization of a binding site of UCN-01, a novel anticancer drug on alpha-acid glycoprotein.

The binding site of 7-hydroxystaurosporine (UCN-01) on alpha-acid glycoprotein (AGP) was studied by fluorescence and ultracentrifugation experiments. Three ligands, propranolol, warfarin and progesterone were employed as marker ligands and quinaldine red was employed as a fluorescent probe. The presence of UCN-01, pro- pranolol, warfarin and progesterone resulted in a significant quenching of the fluorescence of quinaldine red, when bound to AGP, depending upon the potency of the binding to AGP. The construction of Klotz plots indicated that the displacement effects of propranolol, warfarin and progesterone on UCN-01-AGP binding were competitive in nature. These data suggest that the binding site of UCN-01 on the AGP partly overlaps the binding site for basic drugs, acidic drugs, as well as steroid hormones.

Alkaloids↗
PubMed2000

Molecular cloning, sequencing, expression, and site-directed mutagenesis of the 1H-3-hydroxy-4-oxoquinaldine 2,4-dioxygenase gene from Arthrobacter spec. Rü61a.

The ring cleaving enzyme 1H-3-hydroxy-4-oxoquinaldine 2,4-dioxygenase (HOD)) of Arthrobacter spec. Rü61a is part of the quinaldine degradation pathway. Carbon monoxide and N-acetyl-anthranilate are the products formed by dioxygenolytic cleavage of two C-C bonds in the substrate's pyridine ring. The gene coding for HOD was cloned and sequenced. An isoelectric point of pH 5.40 and a molecular mass of 31,838 Da was deduced from the sequence. HOD is shown to be remarkably similar to 1H-3-hydroxy-4-oxoquinoline 2,4-dioxygenase (QDO) of Pseudomonas putida 33/1, but not to other dioxygenases described so far. Consensus regions indicative for any chromophoric cofactor or any catalytically relevant metal were not detected. Sequence comparisons and secondary structure predictions revealed HOD as a new member of the alpha/beta hydrolase fold family. Expression in E. coli yielded recombinant catalytically active His-tagged HOD. S101A and D233A, two mutants of HOD, were obtained by site-directed mutagenesis. Since their residual activity is 43.1% and 62.6%, respectively, they probably are of no catalytic relevance although they might play a role in the interaction between enzyme and substrate.

Amino Acid Sequence↗
PubMed2001

A fluorometric assay for the determination of 1-deoxy-D-xylulose 5-phosphate synthase activity.

We report a novel fluorometric end-point assay for the determination of 1-deoxy-d-xylulose 5-phosphate synthase (DXS) activity based on the reaction of 1-deoxy-D-xylulose 5-phosphate (DX5P) with 3,5-diaminobenzoic acid in an acidic medium to form a highly fluorescent quinaldine derivative. The assay was validated in three ways: (a) for a fixed amount of DXS in the reaction mixture the emitted fluorescence increased linearly with the reaction time, (b) for a fixed reaction time fluorescence intensity increased with the concentration of DXS in the reaction mixture, and (c) the increase in fluorescence intensity correlated (r = 0.99; P < 0.002) with the amount of DX5P formed in the reaction mixture determined radiometrically. The sensitivity of the fluorometric assay is similar to that of the previously described radiometric methods. This assay can be useful for the functional characterization of DXS as well as for the screening of DXS inhibitors with potential antibiotic, herbicidal, or antimalarial action.

Aminobenzoates↗
PubMed1987

Quinoline and quninaldine as naturally occurring inhibitors specific for type A monoamine oxidase.

Type A monoamine oxidase (MAO-A) in human placental mitochondria was competitively inhibited by naturally occurring substances, quinoline and quinaldine, using kynuramine as substrate. Quinoline had a higher affinity for MAO than kynuramine. MAO-A in human brain synaptosomal mitochondria was also competitively inhibited by quinoline, while type B MAO (MAO-B) was reversibly and non-competitively inhibited by quinoline. Quinoline inhibited MAO-A much more potently than MAO-B. Of several compounds structurally similar to quinoline, isoquinoline noncompetitively inhibited MAO-A and -B activity.

Binding, Competitive↗
PubMed2005

Miniaturization of absorbance assays using the fluorescent properties of white microplates.

Miniaturization of high-throughput screening (HTS) assays has several obvious advantages, including increased throughput and lower cost by reduction in reagent consumption. Although absorbance assays are widely used in research laboratories, their application for HTS in a low-volume format has been met with mixed success because they are difficult to miniaturize. Challenges for the miniaturization of absorbance assays include low signal due to short path lengths and meniscus distortions in small well sizes. Here we describe a method to miniaturize absorbance assays to standard, white, low-volume 384-well and 1536-well microplates using a fluorometric plate reader for detection. The premise of this absorbance assay is based on the fluorescent properties of white microplates and the ability of a colored product to quench the fluorescence signal from the plate by absorbing either the excitation light or the emission light. This method was applied to the detection of inorganic phosphate using Quinaldine red and Malachite green dyes and to the monitoring of alkaline phosphatase hydrolysis of p-nitrophenyl phosphate. These assays can be carried out in low volumes, give robust screening statistics, and can be accomplished with a simple, inexpensive fluorometric plate reader.

Combinatorial Chemistry Techniques↗
PubMed2005

Selective binding of coumarin enantiomers to human alpha1-acid glycoprotein genetic variants.

Coumarin-type anticoagulants, warfarin, phenprocoumon and acenocoumarol, were tested for their stereoselective binding to the human orosomucoid (ORM; AGP) genetic variants ORM 1 and ORM 2. Direct binding studies with racemic ligands were carried out by the ultrafiltration method; the concentrations of free enantiomers were determined by capillary electrophoresis. The binding of pure enantiomers was investigated with quinaldine red fluorescence displacement measurements. Our results demonstrated that all investigated compounds bind stronger to ORM 1 variant than to ORM 2. ORM 1 and human native AGP preferred the binding of (S)-enantiomers of warfarin and acenocoumarol, while no enantioselectivity was observed in phenprocoumon binding. Acenocoumarol possessed the highest enantioselectivity in AGP binding due to the weak binding of its (R)-enantiomer. Furthermore, a new homology model of AGP was built and the models of ORM 1 and ORM 2 suggested that difference in binding to AGP genetic variants is caused by steric factors.

Acenocoumarol↗
PubMed1986

Fate and distribution studies of some drugs used in aquaculture.

Residue concentrations of drugs that are administered to fish by bath immersion are related primarily to passage of the drugs across the gills. The elimination of these chemicals by fish can be mediated by biotransformation, but the route of elimination depends on physical characteristics of the chemicals or on their biotransformation products. Uptake of the anesthetics tricaine methanesulfonate, benzocaine, Piscaine, and quinaldine is rapid because they are lipophilic. Loss of their residues also is rapid after the fish are removed from anesthetic solutions because the gradient of concentration favors passage back across the gills. Among therapeutants, uptake and loss of malachite green residues in fish follow the same general pattern as the anesthetics, although at much slower rates; the residues accumulate in the eggs of gravid female salmon after treatment and are detectable in eggs and newly hatched fry. In fish treated with formalin, residues of formaldehyde cannot be detected by currently available analytical methodology. Sulfonamides are metabolized in fish by acetylation and conjugation; however, the free form of the drug appears to be eliminated more rapidly than the acetylated form.

Aminobenzoates↗
PubMed1986

Tryptophan metabolism and urinary quinoline bases in the greyhound.

Three quinoline bases may be found in greyhound urine. 2-aminomethylquinoline is excreted in fresh urine and two others, quinaldine and 2-hydroxymethylquinoline, are formed as the urine decays. Radiolabelling was employed to demonstrate that these bases are derived from the amino acid tryptophan.

Animals↗
PubMed1975

Spectrophotometric determination of acetaminophen and dichloralantipyrine in capsules.

A rapid method for the routine determination of acetaminophen and dichloralantipyrine in capsules is reported. The determination of acetaminophen is based on the ability of its hydrolytic product, p-aminophenol, to produce an intensive yellow color with vanillin. The determination of dichloralantipyrine is based on the fact that it, as well as its major metabolite chloral hydrate, produces a blue color with quinaldine ethiodide. No interferences were encountered, and good recovery and precision data were obtained.

Acetaminophen↗