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PubMed1991

A sensitive method for the detection of beta-galactosidase in transfected mammalian cells.

A sensitive method has been developed for the detection of E. coli beta-galactosidase in transfected HeLa cells. The chromogenic substrate, CPRG (chlorophenol red-beta-D-galactopyranoside), was compared with ONPG (o-nitrophenyl-beta-D-galactopyranoside) by kinetic analysis with purified beta-galactosidase. The Km for CPRG was 1.35 mM and the Vmax was 21.4, whereas the Km for ONPG was 2.42 and the Vmax was 41.1. CPRG at 8.0 mM (6-fold Km) gave 86% of the Vmax and was used as the standard concentration for quantitation of enzyme levels. The Vmax for CPRG was half that for ONPG, and chlorophenol red has an extinction coefficient that is 21-fold higher than o-nitrophenol; these factors make CPRG about 10-fold greater in sensitivity for the quantitation of enzyme levels. The use of Nonidet P-40 to lyse the cells and the use of CPRG as substrate permitted the rapid detection of low levels of enzyme production from transfected human cells that could not be detected using ONPG.

Chlorophenols↗
PubMed1990

Inhibition of lipoxygenase of rat dental pulp and human platelets by phenolic dental medicaments.

The effects of phenolic dental medicaments on lipoxygenase activities of rat dental pulp and human platelets were studied. The major product derived from [14C] arachidonic acid by the homogenate of rat dental pulp was 12-HETE (15-HETE). Eugenol and p-chlorophenol dose-dependently inhibited HETEs formation. The IC50 values of eugenol and p-chlorophenol were 0.62 and 0.34 mM respectively. The concentrations of these compounds that inhibit lipoxygenase were similar to those required to inhibit cyclooxygenase. These compounds also inhibited 12-lipoxygenase of human platelets with a similar range of concentrations. The results show that phenolic dental medicaments inhibit pulpal and platelet lipoxygenase. Thus, inhibition of arachidonic acid metabolism by phenolic dental medicaments via the lipoxygenase pathway may be involved in the analgesic and anti-inflammatory effects of the medicaments in endodontic therapy.

12-Hydroxy-5,8,10,14-eicosatetraenoic Acid↗
PubMed1979

Neurochemical effects of peroral administration of technical pentachlorophenol.

Administration of technical pentachlorophenol in drinking water (20 mg/l) to male Wistar rats caused significant liver concentration of tetrachlorophenol which remained stable during the exposure of 14 weeks. Pentachlorophenol and tetrachlorophenol accumulated to some extent in the perirenal fat whereas only pentachlorophenol could be found in brain. A period of four weeks of chlorophenol-free diet was sufficiently long to allow removal of the major part of the chlorophenol burden. The neurochemical effects included increased acid proteinase activity at the 8th week of exposure. It levelled off while superoxide dismutase activity increased to twice the control level. Glial glutathione peroxidase activity did not change whereas glial glutathione concentration was below the control range at the 12th week of exposure. Cerebral diaphorase activity was below the control range initially, and its activity increased above the control level during the recovery period whereas other biochemical changes levelled off.

Adipose Tissue↗
PubMed1977

[Gas chromatographic method for the determination of P-chlorphenol in the air].

The gas chromatographic method for determination of p-chlorophenol in the air in presence of phenol has been elaborated. A good separation of investigated compounds was achieved using 10% FFAP on Chromosorb W as a stationary phase. Air was sampled to water solution of sodium carbonate. The method enables determination of 0.25 mg/m3 of p-chlorophenol, and 2.5 mg/m3 of phenol at the air sample volume 10 dm3.

Air↗
PubMedDate not supplied

Chemical derivatization analysis of pesticide residues. IX. Analysis of phenol and 21 chlorinated phenols in natural waters by formation of pentafluorobenzyl ether derivatives.

A sensitive, isomer-specific method is described for the simultaneous and quantitative analysis of 22 phenols (phenol, 18 chlorophenols, and 3 chloroalkylphenols) in natural waters. The sample was acidified to pH less than or equal to 2, extracted with dichloromethane, evaporated, and dissolved in acetone. The phenol extract was then reacted with pentafluorobenzyl bromide (PFBBr) to give the PFB ether derivatives. After silica gel column cleanup, the ethers were chromatographed on a 12 m OV-1 fused silica capillary column attached to an electron capture detector (ECD). The detection limit was 0.1 ppb for 1 L samples. Recoveries of phenols from pH 2 water samples fortified at 10, 1, and 0.1 ppb were greater than or equal to 80% in most cases except for phenol which was only 30 to 35% recovered. Coefficients of variation were between 2 and 10% for all phenols. However, phenol recovery was quantitative when the sample volume was reduced to 100 mL. Because ECD sensitivities to the 22 phenol PFB ethers were similar, this method is most suitable for simultaneous screening of nonchlorinated and monochlorinated phenols as well as other higher chlorophenols at trace levels.

Chlorophenols↗
PubMed1988

The association between soft tissue sarcomas and exposure to phenoxyacetic acids. A new case-referent study.

A case-referent study on soft tissue sarcomas (STS) was conducted, to see if previous findings regarding an association between exposure to phenoxyacetic acids or chlorophenols and this tumor type could be reproduced. Fifty-five male STS patients were thereby compared with 220 living and 110 dead population-based referents. Furthermore, another referent group consisting of 190 patients with another type of malignant disease was used in order to evaluate any influence of recall bias on the results. To obtain information about exposure to the studied chemicals, as well as about any other exposures that might be of interest, questionnaires were used, and if necessary these were completed over the phone by an interviewer who had no information regarding case-referent status. All analysis and interpretation of exposure data were done in a blinded manner. Exposure to phenoxyacetic acids gave a roughly three-fold increased risk for STS, thereby confirming previous findings, whereas exposure to chlorophenols was not associated with STS in this study.

Adult↗
PubMed2000

Thermochemical determination of the structure of negative ions on the basis of data from resonance electron capture mass spectrometry. Phenol, its chlorinated derivatives and a thioanalogue

Appearance energies for [M - H](-) ions from phenol (I), 4-chlorophenol (II), pentachlorophenol (III) and pentachlorothiophenol (IV) were measured. The following thermochemical data were deduced from experiment: DeltaH(acid) values of 343.3, 335.7, 317.1 and 317.1 kcal mol(-1) for RH molecules (I, II, III, and IV, respectively) and electron affinities (EAs) of R(.) free radicals 2.55, 2.90, 3.79, and 3.65 eV, respectively. Our data for phenol (I) and 4-chlorophenol (II) demonstrate a higher stabilization of ArO(-) anions than was previously accepted. Using the enthalpic shift procedure for molecules and a series of isodesmic reactions for free radicals, earlier elaborated by the authors, a new Delta$bf H_bf fbf 0$ values for the following gas-phase species were obtained (kcal mol(-1)): C(6)Cl(5)Br (5.0), C(6)Cl(5)SH (8.5), p-ClC(6)H(4)C(.) (2. 0), C(6)Cl(5)C(.) (-15), C(6)Cl(5)S(.) (44). Copyright 2000 John Wiley & Sons, Ltd.

Journal Article↗
PubMed2001

Enhanced selection of an anaerobic pentachlorophenol-degrading consortium.

A rapid enrichment approach based on a pentachlorophenol (PCP) feeding strategy which linked the PCP loading rate to methane production was applied to an upflow anaerobic sludge bed reactor inoculated with anaerobic sludge. Due to this strategy, over a 140-day experimental period the PCP volumetric load increased from 2 to 65 mg L(R)(-1) day(-1) with a near zero effluent concentration of PCP. Dechlorination dynamics featured sequential appearance of 3,4,5-chlorophenol, 3,5-chloro- phenol, and 3-chlorophenol in the reactor effluent. Profiling of the reactor population by denaturing gradient gel electrophoresis (DGGE) revealed a correlation between the appearance of dechlorination intermediates and bands on the DGGE profile. Nucleotide sequencing of newly detected 16S rDNA fragments suggested the proliferation of Clostridium and Syntrophobacter/Syntrophomonas spp. in the reactor during PCP degradation. Published by John Wiley & Sons, Inc.

Anaerobiosis↗
PubMed1996

Electrokinetic chromatography in suppressed electroosmotic flow environment: use of a charged cyclodextrin for the separation of enantiomers and geometric isomers.

Electrokinetic chromatography (EKC), with negatively-charged cyclodextrins (NCDs) added to the buffer, was conducted in polyacrylamide-coated columns under suppression of electroosmotic flow. The equations of migration and resolution for neutral solutes in this mode of chromatography, which for brevity we term NCD-EKC, are presented. The chiral sulfated cyclodextrin, beta-CD-SBE (IV), used in this study is anionic over the entire pH range accessible to capillary electrophoresis, and the coated columns are stable and provide reproducible performance in the pH range 2.5-8.8. Optimum separation was obtained in the pH range where the solutes are neutral. The incorporation of an alkyl spacer between the sulfate ion and the rim of the cyclodextrin allows an unhindered approach and inclusion of neutral solutes in the cyclodextrin cavity. Solute migration time is inversely proportional to the concentration of the chiral selector. Separation (relative migration time difference) increases with decreasing chiral selector concentration and approaches a maximum, beyond which further decreases in chiral selector concentration result in broad peaks and loss of resolution. A chiral selector concentration of 1% in a 10 mM phosphate buffer produced excellent separation of amino acids and dipeptide enantiomers. In addition to being chiral selectors, cyclodextrins are also known as shape selectors. NCD-EKC is particularly suited for the separation of positional isomers of hydrophobic solutes. The separation of aflatoxin isomers and chlorophenol congeners is presented. In the separation of chlorophenols the more hydrophobic trichlorophenols eluted first and the least hydrophobic, phenol, eluted last.

Amino Acids↗
PubMed2006

Use of multivariate analysis for optimization of separation parameters and prediction of migration time, resolution, and resolution per unit time in micellar electrokinetic chromatography.

The optimization of separation parameters in chromatography for better separation and resolution of analytes continues to be a labor intensive procedure usually performed by a trial and error method. A multivariate analysis in the form of multilinear regression (MLR) is used to optimize separation parameters and predict the migration behavior, resolution, and resolution per unit time of achiral (4-chlorophenol, pentachlorophenol, clonazepam, and diazepam) and chiral (1,1'-binaphthyl 2,2'-dihydrogen phosphate (BNP), and 1,1'-bi-2-naphthol (BOH)) compounds in MEKC. Separations of achiral and chiral analytes were performed using an achiral (poly(sodium N-undecylenic sulfate)) molecular micelle and chiral (poly(sodium N-undecanoyl-L-leucylvalinate) or poly(sodium N-undecanoyl-L-isoleucylvalinate)) molecular micelle, respectively, at various operating temperatures, applied voltages, pH values, and molecular micelle concentrations in the BGE. The separation parameters were subsequently used as input variables for MLR models. The models were validated with independent samples. The root-mean-square percent relative error (RMS%RE) is used as a figure of merit for characterizing the performance of the migration time, resolution, and resolution per unit time models. The RMS%RE obtained for predicted migrated times, resolutions, and resolution per unit time of 4-chlorophenol, pentachlorophenol, clonazepam, diazepam, BNP, and BOH ranged between 8 and 19%. The same experimental procedure was used to optimize the separation parameters of six other chiral analytes of different compound class. The predicted migration times, resolutions, and resolution per unit time of the chiral as well as the achiral analytes compare favorably with the experimental migration times and resolutions, indicating versatility and wide applicability of the technique in MEKC.

Chromatography, Micellar Electrokinetic Capillary↗
PubMed2002

Case-control study evaluating the homogeneity and heterogeneity of risk factors between sinonasal and nasopharyngeal cancers.

Sinonasal cancer and nasopharyngeal cancer may share some risk factors because both are located within the upper aerodigestive tract. They may also have different etiological profiles because of anatomic or pathologic differences. However, the similarities and differences in risk factors have rarely been studied within the same population. We assessed the risk factor profiles of sinonasal and nasopharyngeal cancers, using data from a case-control study. The 2 case groups consisted of men aged 31-59 and diagnosed pathologically with sinonasal cancer (n=70) and nasopharyngeal cancer (n=113), respectively. Controls were men without these cancers and selected from the same areas (n=1910). Logistic regression analysis showed that smoking was a risk factor for both sinonasal [odds ratio (OR)=2.5, 95% confidence interval (CI) 1.1-5.4] and nasopharyngeal cancer (OR=1.8, 95%CI 1.1-3.0). However, ever use of barbiturates without a prescription (OR=4.9, 95%CI 1.7-13.8), working with or around cutting oils on a job (OR=1.9, 95%CI 1.1-3.1) and ever having had sinus infections (OR=2.3, 95%CI 1.1-4.6) were associated with nasopharyngeal cancer only. Having received blood products other than a transfusion (OR=9.1, 95%CI 2.2-37.4) and exposure to a pesticide containing 2,4,5-T (OR=5.9, 95%CI 1.5-23.7) were related to sinonasal cancer only. When data analyses were confined to squamous cell type, smoking and exposure to chlorophenols were related to squamous cell tumors at both sites. However, use of barbiturates and sinus problems other than infection only increased the risk of nasopharyngeal carcinoma. Our study suggests that except for smoking and chlorophenol exposure, which are associated with both sites, the risk factor profiles may differ between sinonasal and nasopharyngeal cancers.

Adenocarcinoma↗
PubMed1989

Effect of substrate condition and substituted phenols and methacrylates on toluene diisocyanate/dentin bond strengths.

One aim of this in vitro investigation was to determine the effect of substituting four phenols and two methacrylates with vinyl functions on the dentin bond strengths of several new experimental dentin bonding agents. Another objective was to determine the effect of postextraction age and dentin level within the tooth on tensile bond strengths of these toluene diisocyanate-derived adhesives. Extracted third molars were divided into postextraction age groups and sectioned into three slices approximately 400 microns thick. The four substituted phenols were: eugenol, o-methoxyphenol, o-chlorophenol, and p-cresol. Substituted methacrylates with vinyl ligands were 2-hydroxyethyl methacrylate (HEMA) and 6-hydroxyhexyl methacrylate (HHMA). Results showed that adhesives made with o-chlorophenol, p-cresol, and methoxyphenol with HEMA were the best, while those made with eugenol and HHMA were the worst. The post extraction age of the tooth and the dentin depth had no consistent effect on most adhesive bond strengths which were generally around 10.3 MPa (1500 psi).

Acrylates↗
PubMed1995

Phenol degradation by Acinetobacter calcoaceticus NCIB 8250.

Acinetobacter calcoaceticus NCIB 8250 utilizes phenol as sole source of carbon and energy via an ortho-cleavage pathway. The presence of ethanol in mixed substrate cultivations repressed the utilization of phenol. In fed batch cultivation the phenol tolerance was increased at least 2-fold. Maximum degradation rates of 150 mg phenol/(1 h) and 280 mg phenol/(g h), respectively were observed. Phenol hydroxylase is induced by its substrate and in parallel the catechol-1,2-dioxygenase is detectable. The presence of active phenol hydroxylase is strongly connected with the phenol degradation. Using a spectrophotometric enzyme assay the partially purified phenol hydroxylase was characterized with respect to kinetic parameters. The apparent Km values for phenol, FAD and NADPH were estimated to be 147 microM, 35 microM and 416 microM, respectively. Both FAD and NADPH were essential for maximum activity of the cytoplasmically localized enzyme. No substrate inhibition of phenol hydroxylase by phenol was observed up to 0.8 mM. The pH and temperature optima were pH 7.8 and 33 degrees C, respectively. The partially purified enzyme showed a broad substrate specificity. It hydroxylated the three isomeric cresols, chlorophenols and methylated chlorophenols. Pyrogallol, 3,4-dihydroxy-L-phenylalanine and resorcinol were oxygenated with higher rates than phenol. With the exception of phenol all other enzyme substrates tested did not serve as growth substrates.

Acinetobacter calcoaceticus↗
PubMed2004

Sensitivity enhancement of chlorinated phenols by continuous flow liquid membrane extraction followed by capillary electrophoresis.

This paper describes a new analytical system, based on the combination of continuous flow liquid membrane extraction (CFLME) enrichment and capillary electrophoresis (CE) separation, for analysis of chlorinated phenols in water samples. Five chlorinated phenols including 3-chlorophenol (3CP), 4-chlorophenol (4CP) 2,4-dichlorophenol (DCP), 2,4,6-trichlorophenol (TCP), and pentachlorophenol (PCP) were separated by CE with Tris/sodium dihydrogen phosphate solution containing methanol 1% (v/v) as the run buffer. CFLME related parameters were investigated and optimal enrichment was obtained by using 0.3 mol L(-1) Tris as acceptor and with a sample pH 5.0, a sample flow rate of 4.0 mL min(-1), and an enrichment sample volume of 150 mL. The detection limit (S/N= 3) was 6.9, 1.0, and 1.7 ng mL(-1) for DCP, PCP, and TCP, respectively. The reproducibility (RSD%, n = 6) was 5.7 for DCP, 2.5 for PCP, and 2.8% for TCP (n = 6). The proposed method was applied to the determination of chlorinated phenols in spiked water samples with relatively satisfactory recoveries.

Calibration↗
PubMed2002

Photochemical behaviour of dichlorprop [(+/-)-2-(2,4-dichlorophenoxy)propanoic acid] in aqueous solution.

Aqueous solutions of dichlorprop were irradiated under different conditions of pH, wavelength and oxygenation. The photochemical behaviour was found to be complex and many photoproducts were formed. However, at low concentrations the main photoproducts were 4-chloropyrocatechol, 2-chlorophenol, 4-chlorophenol and 2,4-dichlorophenol. Some other photoproducts were identified, namely 2-(4-chloro-2-hydroxyphenoxy)propanoic acid, 2-(3,5-dichloro-2-hydroxyphenyl)propanoic acid and 2,4-dichlorophenyl acetate. From comparison with results previously obtained with mecoprop [2-(4-chloro-2-methylphenoxy)propanoic acid] it appears that the presence of a chlorine atom in position 2 on the ring strongly modifies the photochemical behaviour.

2,4-Dichlorophenoxyacetic Acid↗
PubMed2002

Acute lethal toxicity of environmental pollutants to aquatic organisms.

The acute lethal toxicity of environment pollutants including chlorophenol, haloalkane, quinone, and substituted nitrobenzene (i.e., nitrophenol, nitrobenzene, nitrotoluene, and aniline) compounds to aquatic organisms was determined. Determination of toxicity of chemicals was performed with chlorella, daphnia, carp, and tilapia. The toxicity of chlorophenols had no relation to the number of chlorine atoms on the benzene ring, but monochlorophenol had lower activity than more chlorine-substituted compounds. The tolerance levels of daphnia and carp to haloalkanes was found to be higher than that of chlorella; toxicity to chlorella was several hundred times higher than to daphnia. The toxicity of naphthoquinone compounds to chlorella and carp was higher than that of anthraquinone. A compound with a monochloride substitution on anthraquinone ring was less toxic to carp than those substituted with amine, hydroxyl, and dichlorine groups. Nitrobenzene compounds with an additional substitution group on the p position were extremely toxic to daphnia and carp.

Adaptation, Physiological↗
PubMed1992

Degradation of phenol and phenolic compounds by Pseudomonas putida EKII.

The phenol-degrading strain Pseudomonas putida EKII was isolated from a soil enrichment culture and utilized phenol up to 10.6 mM (1.0 g.l-1) as the sole source of carbon and energy. Furthermore, cresols, chlorophenols, 3,4-dimethylphenol, and 4-chloro-m-cresol were metabolized as sole substrates by phenol-grown resting cells of strain EKII. Under conditions of cell growth, degradation of these xenobiotics was achieved only in co-metabolism with phenol. Phenol hydroxylase activity was detectable in whole cells but not in cell-free extracts. The specificity of the hydroxylating enzyme was found during transformation of cresols and chlorophenols: ortho- and meta-substituted phenols were degraded via 3-substituted catechols, while degradation of para-substituted phenols proceeded via 4-substituted catechols. In cell-free extracts of phenol-grown cells a high level of catechol 2,3-dioxygenase as well as smaller amounts of 2-hydroxymuconic semialdehyde hydrolyase and catechol 1,2-dioxygenase were detected. The ring-cleaving enzymes were characterized after partial purification by DEAE-cellulose chromatography.

Biodegradation, Environmental↗
PubMed1975

Biodegradation of alpha-hexachlorocyclohexane. V. Characterization of the major urinary metabolites.

1. Free 2,4,5- and 2,4,6-trichlorophenol (TCP) have been identified by co-crystallization with authentic carrier as constituents of the urine of rats given 3-H-labelled alpha-hexachlorocyclohexane (alpha-HCH). The two TCP's constituted 7% and 63%, respectively, of the free phenol fraction which was found to account for less than 5% of all urinary metabolites. 2. 75% of the label contained in the urine of rats collected for four weeks after an i.p. dose of 14-C-alpha-HCH could be extracted into an organic solvent after alkaline and acid hydrolysis. The radioactive material thus extracted was examined by TLC and GLC. It is shown to consist mainly of chlorophenols and chlorothiophenols. 3. The extracts' major constituent was 2,4,6-TCP. Its amount was determined by GLC and was found to account for, on average, 45% of the total urinary metabolites. In conjunction with other evidence, this is considered to establish 2,4,6-TCP as the major product of alpha-HCH-biodegradation in the rat. 4. Chromatographic evidence is presented for 2,3,4,5-tetrachlorophenol and 2,4,5-TCP being other components of the chlorophenol fraction isolated from hydrolysed urine. 5. The amount of label associated with the chlorothiophenol fraction suggests a pathway involving endogenous thiol to be of significance in alpha-HCH-biodegradation in rats. Pretreatment with the drug itself increased the proportion of label associated with the fraction.

Animals↗