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Pyrocatechol has been identified as one of two main substances isolated from bark of aspen (Populus tremuloides Michx.) which inhibited Hypoxylon pruinatum (Klot.) Cke. Total inhibition of this fungus was obtained at a dosage of 640 parts per million. Tests with bark extract from two localities showed that inhibition was maximal in samples obtained in the dormant season and from the base of the trees.
We have already reported on a radioreceptor assay for catecholamines utilizing the microsome fraction of bovine myocardium as a catecholamine (CA) receptor and 3H-norepinephrine as a labelled CA. In order to increase the sensitivity of the radioreceptor assay, we used 4-(2-iodoethyl) pyrocatechol (125I-CA) as a ligand instead of 3H-norepinephrine and performed a radioreceptor assay for CA. The following results were obtained: 1) 125I-CA was able to bind alpha-receptors prepared from bovine myocardium. 2) The optimal amount of the microsomal fraction was 250 micrograms/tube, when 125I-CA of 50,000 c.p.m. was used. The appropriate conditions for incubation were 90 minutes at 20 degrees C in a pH 7.0 sucrose solution. 3) By this method utilizing 125I-CA, norepinephrine was detectable in a range from 500 pg to 10 ng/tube. 4) Various compounds with a catechol nucleus showed cross-reaction in this radioreceptor assay system. 5) Whereas beta-adrenergic blocking agents did not inhibit the binding of 125I-CA, phentolamine, a short acting type of alpha-adrenergic blocking agents, was effective in inhibiting the binding. However, dibenamine and phenoxybenzamine, long acting types of alpha-adrenergic blocking agents, increased the binding of 125I-CA to the microsomal fraction. 6) Utilizing this phenomenon, norepinephrine was detectable in the range from 100 pg to 5 ng/tube.
A method for the visual detection of fluoride is presented using an aqueous solution of Pyrocatechol Violet (PV), which changes its color from yellow to blue by the formation of a ternary complex with Zr(H2O)2EDTA; also, the blue color of PV-Zr-EDTA readily shifts to orange red upon the addition of a moderate concentration of fluoride. The mechanism has been interpreted by a ligand-exchange reaction of PV coordinated to Zr(IV) with fluoride. The effect of various factors, such as the pH, ratio of Zr(H2O)2EDTA and PV, and diverse ions were studied to optimize the conditions for the reaction of PV-Zr-EDTA with fluoride. The present naked-eye detection system provides a simple, quick, and sensitive method for the determination of fluoride in the concentration range 1.5 x 10(-5) to 1.5 x 10(-4) mol dm(-3). The detection limit of the method was observed to be 4.5234 x 10(-4) mol dm(-3) with a correlation coefficient of 0.9955. The developed chemosensor was applied to the detection of fluoride in industrial effluents.
The purpose of this study is to investigate drug's interference on proteinuria's determination with pyorcatechol violet (Vitros technology). Five drugs were selected: gelatin based vascular replacement fluids (Plasmion), deferoxamine (Desféral), ceftriaxone (Rocéphine), ceftazidime (Fortum) and imipeneme (Tienam). To state precisely the role played by slide's technology, a liquid phase dosage was simultaneously made with pyrocatechol violet. No interference was notified with therapeutical range for four of them: gelatin, deferoxamine, ceftazidime and imipeneme. Slides technology prevents from gelatin's interference because the colorant is sensible to this drugs. On the other hand, positive interference was observed with ceftriaxone for urinary concentration upper than 0.75 g/L. This concentration is lower than that notified by Vitros laboratory in the technical data.
Eriochrome cyanine R (ECR) and pyrocatechol violet (PCV) have been tested as reagent for the determination of amitriptyline (AMT). They react in aqueous media with AMT forming coloured compounds sparingly soluble in walter. Optimal conditions for the reaction have been established and new extractive-spectrophotometric methods have been developed for the determination of amitriptyline. It can be assayed in the concentration range 8.0-80.0 microg/ml for the ECR method and in the range 1.5-15.0 microg/ml in the case of PCV. The methods were applied to the determination of amitriptyline in albumin and pharmaceutical preparations. The UV-VIS studies of the reagents and the formed compounds were performed.
In weak acid medium (pH 6.20), Fe(III) and Mo(VI) can form colored complexes with pyrocatechol and quantitatively adsorbed on 717 strong base anion exchange resin. The apparent molar absorption coefficients of resin phase are epsilon = 4.1 x 10(4) L/(mol x cm) at 520 nm for Fe(III) and epsilon = 9.0 x 10(4) L/(mol x cm) at 400 nm for Mo(VI). Beer's law is obeyed for Fe (III) and Mo(VI) in the range of 0-2.2 mg x L(-1) and 0-1.6 mg x L(-1). The method has been applied to the determination of trace Fe(III) and Mo(VI) in ground water. The relative standard deviations are 3.3% and 3.2%, respectively.
A new procedure for detecting HRP in nerve tissue is described which is based on the use of pyrocatechol to stabilize the oxidation products of o-tolidine and o-dianisidine in citric acid/ammonium acetate buffer of pH 4.85. In both cases the precipitate obtained is insoluble, stable and more visible than when any variant of the diaminobenzidine method is employed, and the morphological image of neurons and nerve fibres labelled with HRP is superior to that produced by the tetramethylbenzidine/sodium nitroprusside method. There is no non-specific precipitation, and no retraction of nerve tissue has been observed. The performance of the method is improved further using either o-tolidine/pyrocatechol or o-dianisidine/pyrocatechol in conjunction with glucose oxidase, which may be useful if it is desired to obtain Golgi-like images of HRP-bearing cells or to display weakly HRP-labelled nerve fibres.
A new simple and sensitive spectrophotometric method is suggested for determining the catecholase activity of diphenoloxidase. The method is based on the enzymatic oxidation of pyrocatechol to 1,2-benzoquinone (BQ) in the presence of the excess of ethylenediamine sulphate (EDA). The condensation product (products) of BQ and EDA (P365) is stable in the solution and possesses strong absorption in the range of 365 nm. The molar absorption factor, E365 (under condition that the molar reaction ratio of catechol to P365 is 1:1) is 15500 M-1 cm-1 on the average. Optimal reaction conditions (pH 7.0, T=25-30 degrees C, [EDA]o = 5 mg/ml) are determined. The advantages and restrictions of the suggested technique in comparison with the methods described earlier are discussed.
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