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PubMed1999

Determination of niobium(V) and tantalum(V) as 4-(2-pyridylazo)resorcinol-citrate ternary complexes in geological materials by ion-interaction reversed-phase high-performance liquid chromatography.

A method for the simultaneous separation and determination of Nb(V) and Ta(V) as ternary complexes formed with 4-(2-pyridylazo)resorcinol (PAR) and citrate was developed using ion-interaction reversed-phase high-performance liquid chromatography on a C18 column. Method parameters, such as pre-column complex formation conditions and composition of the complexes were investigated using spectrophotometry and HPLC. Under the optimum conditions, the Nb(V) and Ta(V) complexes were eluted within 12 min with a mobile phase of methanol-water (32:68, v/v) containing 5 mM acetate, 5 mM TBABr and 5 mM citrate buffer at pH 6.5, with detection at 540 nm. A typical separation efficiency was 33,000 and 20,000 theoretical plates per metre for Nb(V) and Ta(V), respectively. The relative standard deviation of retention times for the Nb(V) and Ta(V) complexes were 0.16% and 0.17% and for peak areas were 0.28% and 1.36%, respectively. The detection limits (signal-to-noise ratio = 3) for Nb(V) and Ta(V) were 0.4 ppb and 1.4 ppb, respectively. Results obtained for standard reference rock samples agreed well with certified values and results obtained by inductively coupled plasma MS.

Chromatography, High Pressure Liquid↗
PubMed2000

On-line preconcentration of niobium(V) and tantalum(V) as 4-(2-pyridylazo) resorcinol-citrate ternary complexes in geological samples by ion interaction high-performance liquid chromatography.

4-(2-Pyridylazo) resorcinol (PAR) and citrate were used as pre-column complexing agents for the determination of Nb(V) and Ta(V) as ternary complexes in geological samples. Aliquots of 2 ml of the standard and sample solutions containing the Nb(V) and Ta(V) complexes were loaded onto a concentrator column (C18, 0.4 cm x 4.6 mm) with a carrier mobile phase comprising 20% (v/v) methanol and containing 5 mM acetic acid, 5 mM citric acid and 10 mM tetrabutylammonium bromide (TBABr), pH 6.5 at 2 ml/min for 2 min, with the effluent being directed to waste. An automatic switching valve was then switched to flush both complexes from the concentrator column onto a C18 analytical column using a mobile phase comprising 32% (v/v) methanol and containing 5 mM acetic acid, 5 mM citric acid and 3 mM TBABr, pH 6.5 for 2.5 min. The switching valve was then switched back to the original position, and cleaned with methanol for 7 min to eliminate unwanted species still adsorbed to the concentrator column. This procedure prevented later eluting compounds from reaching the analytical column, which reduced the overall run time. The detection limits of Nb(V) and Ta(V) (determined at a signal-to-noise ratio of 3, detection wavelength of 540 nm and a 2-ml sample volume) were 0.012 and 0.039 ppb for Nb(V) and Ta(V), respectively. Recoveries of Nb(V) and Ta(V) were 99.4 and 96.2%, respectively. The HPLC results obtained from the reference granite and basalt samples agreed well with inductively coupled plasma MS and certified values, but the HPLC method yielded slightly low values of the Nb/Ta ratio.

Chromatography, High Pressure Liquid↗
PubMed2001

Postinfarction ventricular septal perforation repair with endoventricular circular patch plasty using double patches and gelatin-resorcinol-formaldehyde biological glue.

We describe a technique for repairing the ventricular septal perforation 10 days post acute anteroseptal myocardial infarction using the modified infarction exclusion method. The repair involves endoventricular circular patch plasty and application of gelatin-resorcinol-formaldehyde biological glue in the space between a Teflon felt patch on the infarcted septum and a bovine pericardial patch in the left ventricular cavity. Its use in a patient resulted in an almost normal shaped interventricular septum and left ventricular cavity as well as normal left ventricular function.

Aged↗
PubMed1997

Pneumostatic effect of gelatin-resorcinol formaldehyde-glutaraldehyde glue on thermal injury of the lung: an experimental study on rats.

OBJECTIVE: Recently, the use of gelatin-resorcinol formaldehyde-glutaraldehyde (GRFG) glue has been reported in vascular surgery, especially in surgery for acute aortic dissection. However, reports concerning its use in lung surgery are quite rare. Although the strong adhesion and tensile strength of GRFG glue to fresh incisional wounds of the lung has been demonstrated experimentally, the effectiveness of this adhesive on thermal injury with severe tissue degeneration has not yet been reported. METHODS: We experimentally evaluated the ability of GRFG glue to seal air leaks through severely degenerated tissues after thermal injury on rat lung, and compared its performance with two reference adhesives: fibrin glue and EDH-adhesive. RESULTS: The GRFG glue provided complete pneumostasis immediately after the sealing in the presence of positive pressure ventilation, unlike the other two reference adhesives. The fate and biocompatibility of the three glues were examined histologically at 1 h and 3, 8, and 20 days after treatment. The GRFG glue tightly adhered to the degenerated tissue surface and was gradually fragmented and absorbed. The healing process was favorable, indicating good biocompatibility. Local tissue irritability was negligible. CONCLUSIONS: Even in the presence of tissue degeneration and positive pressure ventilation, the GRFG glue has proved efficacious as a surgical adhesive in lung surgery because of its ability to bind tissue rapidly and tightly.

Animals↗
PubMed2002

Spectrophotometric studies on the simultaneous determination of cadmium and mercury with 4-(2-pyridylazo)-resorcinol.

A new method for direct spectrophotometric determination of cadmium with 4-(2-pyridylazo)-resorcinol is reported. Absorption maximum, molar absorptivity and Sandell's sensitivity of the 1:1 (M:L) complex are 510 nm, 2.5 x 10(5) l mol(-1) cm(-1) and 3.55 ng cm(-2), respectively. A linear calibration graph is obtained up to 4.49 microg ml(-1). The zero-crossing measurement technique is found suitable for the direct measurement of the first-derivative value at the specified wavelengths. Cadmium(II) (0.42-9.2 microg ml(-1)) and mercury(II) (0.35-7.4 microg ml(-1)) in different ratios have been determined simultaneously. A critical evaluation of the proposed method is performed by statistical analysis of the experimental data. The developed method was applied to the simultaneous spectrophotometric determination of Cd and Hg in some synthetic mixtures and was found to give satisfactory results.

Biophysical Phenomena↗
PubMed1987

Effects of calcium ion on ternary complexes formed between 4-(2-pyridylazo)resorcinol and the two-zinc insulin hexamer.

As a means for probing the microenvironment of zinc in the insulin hexamer and to investigate the effects of calcium ion on the assembly and the structure of the two-zinc insulin hexamer, the thermodynamics and kinetics of the reaction between the chromophoric divalent metal ion chelator 4-(2-pyridylazo)resorcinol (PAR) and zinc-insulin have been investigated over a wide range of conditions. For [PAR]0 much greater than [Zn2+]0 and [Zn2+]/[In] less than or equal to 0.33, the reaction leads to the sequestering and ultimate removal of all of the insulin-bound Zn2+; for [Zn2+]0 much greater than [PAR]0, two stable ternary complexes are formed where Zn2+ has ligands derived from PAR as well as from hexameric insulin. For [Zn2+]/[In] ratios below 0.33, the equilibrium distribution between the two ternary complexes is dependent on the [Zn2+]/[In] ratio. One of the complexes is assigned to the monoanion of PAR coordinated to Zn2+ that resides in a His-B10 site. The other complex is proposed to involve the coordination of (PAR)Zn to the site formed by the alpha-NH2 group of Phe-B1 and the gamma-carboxylate ion of Glu-A17 across the dimer-dimer interface on the surface of the hexamer. With either PAR or zinc-insulin in large excess, the kinetics of the PAR optical density changes are remarkably similar and biphasic. The faster step is first order in PAR and first order in insulin-bound Zn2+ (k congruent to 3 X 10(3) M-1 s-1) and involves the formation of an intermediate in which PAR is coordinated to insulin-bound zinc at the His-B10 site.(ABSTRACT TRUNCATED AT 250 WORDS)

Binding Sites↗
PubMed2003

New efficient procedure for the use of diethoxyphosphoryl as a protecting group in the synthesis of polyazamacrocycles. Preparation of polyazacyclophanes derived from resorcinol.

The synthesis of polyazamacrocycles containing an electron-rich aromatic subunit derived from resorcinol is described. The reported synthetic procedure is based on the use of diethoxyphosphoryl (Dep) as an amine protecting group. The new conditions employed for the cyclization reaction allow for a generalized use of Dep in the synthesis of polyazamacrocycles.

Amines↗
PubMed2006

Novel synthesis of desymmetrized resorcinol derivatives: aryl fluoride displacement on deactivated substrates.

A short, high-yielding synthesis of differentially substituted resorcinol derivatives has been developed that utilizes 1,3-difluorobenzene as the starting material and employs sequential nucleophilic aromatic substitution (S(N)Ar) reactions to generate desymmetrized products. The scope and limitations of the second S(N)Ar reaction on the deactivated 1-alkoxy-3-fluorobenzene intermediates have been investigated. This methodology has also been employed in the synthesis of desymmetrized catechol derivatives from 1,2-difluorobenzene.

Catechols↗
PubMed2004

Diastereoselective dearomatization of resorcinols directed by a lactic acid tether: unprecedented enantioselective access to p-quinols.

An operationally simple oxidative dearomatization of resorcinol derivatives is reported that employs an inexpensive chiral directing group. The method provides access to a variety of p-quinol derivatives in good yield and diastereoselectivity. A short reductive process affords 4-hydroxy-4-alkylcyclohexenone derivatives in excellent yields and enantiomeric excesses.

Hydroquinones↗
PubMedDate not supplied

[Peroxidase-catalyzed oxidation of 3,3',5,5'-tetramethylbenzidine in the presence of 2,4-dinitrosoresorcinol and polydisulfide derivatives of resorcinol and 2,4-dinitrosoresorcinol].

A comparative study of the kinetics of peroxidase-catalyzed oxidation of 3,3',5,5'-tetramethylbenzidine (TMB) in the presence of 2,4-dinitrosoresorcinol (DNR), its polydisulfide derivative [poly(DNRDS)], and resorcinol polydisulfide [poly(RDS)], substances that competitively inhibit the formation of TMB conversion product, was carried out. The inhibition constants, Ki for DNR, poly(DNRDS), and poly(RSD) were determined at 20 degrees C and pH 6.4 to be 110, 13.5, and 0.78 microM, respectively. The stoichiometric coefficients of inhibition were calculated to be 0.38 and 76 for poly(DNRDS) and poly(RDS), respectively. In the pH range 6.4-7.0, the initial rates of the peroxidative oxidation of TMB, and its mixtures with DNR and poly(DNRDS) and the Ki value for poly(RDS) substantially decreased with increasing pH. The kinetic parameters of poly(RDS) (Ki 0.22-0.78 microM and f76) suggest that it is the most efficient inhibitor of peroxidase oxidation of TMB: in micromolar concentrations, it completely stops this process and can be used in EIA.

Benzidines↗
PubMed2005

The results of five coded compounds: genistein, metaproterenol, rotenone, p-anisidine and resorcinol tested in the pH 6.7 Syrian hamster embryo cell morphological transformation assay.

The pH 6.7 Syrian hamster embryo (SHE) cell morphological transformation assay is a short-term in vitro test that has been used to predict rodent carcinogenicity. Previous reports have indicated that the SHE assay has an overall concordance of approximately 80% with the 2 year rodent bioassay. We selected five compounds, genistein, metaproterenol, rotenone, p-anisidine and resorcinol, that had extensive genotoxicity and carcinogenicity data and tested them in the standard 7 day exposure SHE assay. Somewhat surprisingly, the SHE assay misclassified the actual rodent carcinogenicity of four out of the five test compounds. It is difficult to explain these findings as the actual mechanisms of SHE cell morphological transformation are currently unknown. However, it is obvious that in these studies there was no simple correlation between in vitro genotoxicity, morphological transformation in SHE cells and rodent carcinogenicity. Clearly, further research is required to accurately assess the role of the SHE assay in the carcinogenic risk assessment of new chemical entities.

Aniline Compounds↗
PubMed2006

Biocontrol of avocado dematophora root rot by antagonistic Pseudomonas fluorescens PCL1606 correlates with the production of 2-hexyl 5-propyl resorcinol.

A collection of 905 bacterial isolates from the rhizospheres of healthy avocado trees was obtained and screened for antagonistic activity against Dematophora necatrix, the cause of avocado Dematophora root rot (also called white root rot). A set of eight strains was selected on the basis of growth inhibitory activity against D. necatrix and several other important soilborne phytopathogenic fungi. After typing of these strains, they were classified as belonging to Pseudomonas chlororaphis, Pseudomonas fluorescens, and Pseudomonas putida. The eight antagonistic Pseudomonas spp. were analyzed for their secretion of hydrogen cyanide, hydrolytic enzymes, and antifungal metabolites. P. chlororaphis strains produced the antibiotic phenazine-1-carboxylic acid and phenazine-1-carboxamide. Upon testing the biocontrol ability of these strains in a newly developed avocado-D. necatrix test system and in a tomato-F oxysporum test system, it became apparent that P. fluorescens PCL1606 exhibited the highest biocontrol ability. The major antifungal activity produced by strain P. fluorescens PCL1606 did not correspond to any of the major classes of antifungal antibiotics produced by Pseudomonas biocontrol strains. This compound was purified and subsequently identified as 2-hexyl 5-propyl resorcinol (HPR). To study the role of HPR in biocontrol activity, two Tn5 mutants of P. fluorescens PCL1606 impaired in antagonistic activity were selected. These mutants were shown to impair HRP production and showed a decrease in biocontrol activity. As far as we know, this is the first report of a Pseudomonas biocontrol strain that produces HPR in which the production of this compound correlates with its biocontrol activity.

Ascomycota↗
PubMed2000

R6 hexameric insulin complexed with m-cresol or resorcinol.

The structures of three R(6) human insulin hexamers have been determined. Crystals of monoclinic m-cresol-insulin, monoclinic resorcinol-insulin and rhombohedral m-cresol-insulin diffracted to 1. 9, 1.9 and 1.78 A, respectively, and have been refined to residuals of 0.195, 0.179 and 0.200, respectively. In all three structures, a phenolic derivative is found to occupy the phenolic binding site, where it forms hydrogen bonds to the carbonyl O atom of CysA6 and the N atom of CysA11. Two additional phenolic derivative binding sites were identified within or between hexamers. The structures of all three hexamers are nearly identical, although a large displacement of the N-terminus of one B chain in both monoclinic structures results from coordination to a sodium ion which is located between symmetry-related hexamers. Other minor differences in structure arise from differences in packing in the monoclinic cell compared with the rhombohedral cell. Based upon the differences in conformation of the GluB13 side chains in T(6), T(3)R(f)(3) and R(6) hexamers, the deprotonation of these side chains appears to be associated with the T-->R conformational transition.

Cresols↗
PubMedDate not supplied

Arrest and control of carious lesions: a study based on preliminary experiments with resorcinol-formaldehyde resin.

An experimental investigation has been made into the possibilities of retarding the progress of carious attack by infiltrating cariostatic material into enamel lesions. The problems associated with this kind of procedure are discussed against the background of experimental observations made using a formulation based on a resorcinol-formaldehyde resin.

Animals↗
PubMed1998

Effects of certain resorcinol derivatives on the tyrosinase activity and the growth of melanoma cells.

Effects of certain resorcinol derivatives on tyrosinase activity, melanin formation and some other biological activities were studied in order to develop a new, potent depigmentor and/or antimelanoma drug. NKO-09, having isopentyl group in position 6 of resorcinal, exhibited a more potent effect than the compounds which have methyl (NKO-10), ethyl (NKO-11), hexyl (KOM-14), octyl (NKO-14), decyl (NKO-19), dodecyl (NKO-15) and tetradecyl (NKO-16) group in inhibiting the tyrosinase activities (both tyrosine hydroxylation and dopa oxidation). NKO-09 was more potent than hydroquinone in inhibiting the tyrosine hydroxylation; furthermore, NKO-09 inhibited the dopa oxidation different from hydroquinone. In the studies on melanin formation, protein synthesis and the growth of the melanoma cells, NKO-09 caused the most potent effect among the test compounds, except for the growth of the melanoma cells. KOM-14 was more potent than NKO-09 in the antimelanoma activity, and its effect was superior than that of 5-fluorouracil. From these findings, it is suggested that NKO-09 and KOM-14 can be used as an efficacious depigmentor and antimelanoma drug, respectively.

Animals↗
PubMed1991

Application of biological samples treated by wet-digested mineralization to cation-exchange high-performance liquid chromatography with post-column reaction by 4-(2-pyridylazo)-resorcinol.

To quantify metals in biological samples, we tried to find good conditions for wet-digested mineralization of the samples and for separation of metal ions in chromatography. A 500 microliters volume of aliquot was transferred to a glass tube, and was evapolated at 100 degrees C for 2 hours. A 5.5 ml volume of a mixture of concentrated nitric acid-70% perchloric acid (10: 1, v/v) was added and heated, consecutively, at 80 degrees C for 12 hours, at 140 degrees C for 2 hours, at 180 degrees C for 2 hours, and finally at 190 degrees C for 1 hour to evapolate the residual acids. After addition of 500 microliters of 10 mM nitric acid, the metals were extracted by a suspension mixer (32 r.p.m., 1 hour). One hundred microliters of the extracted solution was applied to the chromatographic system: cation-exchange column, TSKgel IC-Cation SW (Tosoh Co.); eluent, 0.35 M lactic acid-0.35 M sodium lactate (pH 3.0); flow rate, 0.7 ml/minute; column temperature, 30 degrees C. After adding a color-forming reagent (100 mg/l 4-(2-pyridylazo)-resorcinol in 40 g/l Na2CO3; flow rate, 0.7 ml/minute) to the effluent, five different metal ions of Cd2+, Co2+, Cu2+, Ni2+ and Zn2+ were detected at 520 nm. The peaks were separated in approximately 25 minutes, and were quantified even at the 1-10 ppb levels. The present procedures were considered to provide simultaneous detection and accurate quantitation of the above five metals in the biological samples.

Animals↗
PubMed1996

Kinetics of the course of inactivation of yeast alcohol dehydrogenase by 4-(2-pyridylazo)-resorcinol.

The kinetic theory of the substrate reaction during modification of enzyme activity previously described by Wang and Tsou has been applied to a study on the kinetics of the course of inactivation of alcohol dehydrogenase by 4-(2-pyridylazo)-resorcinol (PAR). The results showed that the inhibition of this enzyme by PAR was irreversible. A plot of 1n([P] infinity -[P]) versus give a straight line, suggesting that the inactivation kinetic course is monophasic. The kinetic analysis of the substrate reaction with different concentrations of the substrate and the inactivator has shown that the inactivation of yeast alcohol dehydrogenase by PAR involves complex formation, and that the substrate ethanol competes with PAR at the active site of the enzyme. The dissociation constants between the substrates and the enzyme as well as the microscopic rate constants for the inactivation of the enzyme have been determined.

Alcohol Dehydrogenase↗
PubMed1999

[An effective case of a new biological adhesive agent, gelatin-resorcinol formaldehyde-glutaralhyde glue (GRFG-glue) in treating refractory pulmonary fistula following lobectomy for pulmonary aspergilloma].

We report a successful case of thoracoscopic therapy using a new biological adhesive agent, Gelatin-Resorcinol Formaldehyde glue (GRFG glue) for refractory pulmonary fistula. A 69-year-old male underwent right upper lobectomy for lung aspergilloma. Air leakage began 11 days after lobectomy. Closing alveolar fistula was performed 28 days after first operation. Relapsing air leakage began 2 days after second operation. The insertion of fibrin glue through thoracoscope at two times was not effective for refractory pulmonary fistula. But the insertion of GRFG glue was effective to close the fistula completely.

Aged↗