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PubMed1981

[The effect of some hexachlorobenzene catabolites on the porphyrin metabolism of rats (author's transl)].

In answering the question as to what role possible metabolites of hexachlorobenzene play in the procreation of toxic hexachlorobenzene porphyria in rats, both pure hexachlorobenzene and different mixtures were fed to them. In each case 20% of the hexachlorobenzene was replaced by pentachlorophenol, 1,2,4,5-tetrachlorobenzene, 1,2,3,4-tetrachlorobenzene, 1,2,3,5-tetrachlorobenzene, 2,3,4,5-tetrachlorophenol, 2,3,5,6-tetrachlorophenol, 2,3,4,6-tetrachlorophenol or chloranil. The determination of porphyrins at different intervals once the feeding had started did not give rise to an increase in the porphyria in any of these substances--which are seen as metabolites of hexachlorobenzene. Instead there was a distinct decrease in individual cases. From this the conclusion is drawn that none of the tested substances is the metabolite of hexachlorobenzene, which is in fact responsible for the hexachlorobenzene porphyria.

Animals↗
PubMedDate not supplied

[Evaluation of wood preservative pollutants of indoor air].

The evaluation of indoor pollution by wood preservatives and pesticides has been a matter of increasing interest for the past years. The present paper reviews actual knowledge. The so-called "wood preservative syndrome" is referred to. Basics and evaluation criteria concerning the investigation of external exposure (wood, dust, air) and human biomonitoring is summarized. Several substances, in particular pentachlorophenol, lindane and pyrethroids, and principle possibilities to decrease exposure are considered.

Air Pollution, Indoor↗
PubMedDate not supplied

Metabolic chiral inversion of stiripentol in the rat. I. Mechanistic studies.

To study enantioselective aspects of the disposition of stiripentol (STP), a chiral allylic alcohol undergoing development as an antiepileptic drug, a stereoselective synthesis was developed and the configuration of the two enantiomers determined to be (R)-(+) and (S)-(-). Following a single oral dose (300 mg kg-1) of the individual enantiomers to adult male Sprague-Dawley rats, it was found that (R)-STP was transformed extensively to its antipode, whereas little inversion was detected when (S)-STP was administered. Studies on the mechanism of this apparently unidirectional chiral inversion revealed that the phenomenon was dependent on the presence of the side-chain C==C double bond, because the enantiomers of the corresponding saturated alcohol (D2602) did not interconvert in vivo. Experiments with analogs of STP labeled with deuterium or oxygen-18 at the chiral center showed that, whereas the deuterium was retained in vivo, partial loss of the 18O occurred from both enantiomers of the drug. Pretreatment of rats with pentachlorophenol (40 mumol kg-1 i.p.), an inhibitor of sulfation (and possibly other conjugation reactions), led to a marked decrease in the rate of conversion of (R)-STP to its antipode, suggesting that the chiral inversion phenomenon may be mediated, at least in part, by an enantioselective conjugation process.

Administration, Oral↗
PubMed1994

[Oxygenated cytochrome bd from Escherichia coli could be transformed into an oxidized form by lipophilic electron acceptors].

The cytochrome bd complex as isolated from Escherichia coli under aerobic conditions is in a stable oxygenated form [formula: see text], characterized by an intense peak at 650 nm in an absolute absorption spectrum. The commonly used oxidants ferricyanide and persulfate have no effect on the oxygenated form, whereas the addition of lipophilic electron acceptors, such as tetrachlorobenzoquinone or ferricinium, results in the decay of the heme d oxy-complex and the enzyme transition into the fully oxidized form, [formula: see text]. Interaction of the oxygenated cytochrome bd complex with both tetrachlorobenzoquinone and ferricinium is suppressed by pentachlorophenol, an inhibitor of the enzyme ubiquinol oxidase activity. It is suggested that redox centers of cytochrome bd reside in the hydrophobic environment which can prevent their interaction with the hydrophilic oxidants.

Chloranil↗
PubMed1996

[Multiple chemical sensitivity disorder in patients with neurotoxic illnesses].

The data of 466 subjects suffering from neurologic disorders which are suggested to be caused by neurotoxic agents in their environment retrospectively was evaluated and documented. Among these cases there were 151 subjects with symptoms of Multiple Chemical Sensitivity Disorder (MCSD). The relationship between the neurological health impairments and neurotoxic agents in the environment of these patients was characterised using five different categories (probable = A, possible = B, uncertain = C, unclarified = D, not probable = E). From the 466 patients 320 subjects (69%) could be assigned to the categories A and B, respectively. Within theses 320 cases with chronic neurotoxic health impairments 136 subjects (79 females and 57 males) showed signs of MCSD. Age and gender of cases as well as duration and character of exposure to neurotoxic substances retrospectively were assessed from the explicit files of the patients, which had been made anonymous for this purpose. Frequency of characteristic symptoms of neurotoxicity were analysed. Results are given for patients with neurotoxic health impairments with MCSD (n = 136) and without MCSD (n = 184). Neurotoxic substances which were used as indoor wood preservatives (mainly Pentachlorophenol and/or Lindane) were found to be the causative agents in 63% of the cases with neurotoxic health impairments and MCSD. Other important neurotoxic substances to which the patients were mainly exposed were organic solvents (25%), formaldehyde (15%), dental materials (15%), pyrethroides (13%), and other biocides (19%) (multiple exposures were possible). The time of exposure was calculated as being > or = 10 years for 55% of the patients with MCSD and for 50% of the group with neurotoxic health impairments but without MCSD. Out of the 184 cases with neurotoxic health impairments but without MCSD there were 22%, and out of the 136 cases with MCSD there were 39% who showed all symptoms of chronic fatigue syndrome. 53% of the cases with MCSD had an allergic disposition compared to only 20% of the cases without MCSD. This work is not a controlled epidemiological study but a retrospective documentation and evaluation of data related to environmental medicine. With the present documentation in this purely descriptive manner the proof of a causal relationship was not possible or intended. But because corresponding epidemiological studies are lacking, this documentation can give important information on characteristic features of Multiple Chemical Sensitivity Disorder and chronic neurotoxic health impairments. Such information is essential for planning and carrying out epidemiological studies urgently needed in this field.

Adolescent↗
PubMed1999

Determination of chlorophenols in human urine based on the integration of on-line automated clean-up and preconcentration unit with micellar electrokinetic chromatography.

A new method was developed and validated for the determination of chlorophenols in human urine by using micellar electrokinetic chromatography (MEKC) coupled via a mechanic arm to an on-line automatic clean-up and preconcentration unit for urine samples. Separation is accomplished by using a selective buffer consisting of 15 mM borate, 25 mM phosphate and 100 mM sodium dodecyl sulfate (SDS) at pH 9.1 in addition to a positive power supply of 25 kV at 18 degrees C. The proposed capillary electrophoresis (CE) method allows the separation of 11 chlorophenols within 7 min with a reproducibility as relative standard deviation (RSD) between 2.6% and 7.2%, and limits of detection (LODs) between 0.08 and 0.46 microg/mL for all chlorophenols. Urine samples were previously hydrolyzed with 37% HCl at 80 degrees C for 60 min and then cleaned on a C-18 mini-column. Recoveries ranged from 58% to 103%. The preconcentration treatment affords limits of determination between 4 and 12 ng/mL for all chlorophenols except pentachlorophenol and 4-chlorophenol, which could not be determined. The overall analysis time, including on-line clean-up, preconcentration and electrophoretic separation is 20 min per sample.

Chlorophenols↗
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↗
PubMedDate not supplied

Development of California Public Health Goals (PHGs) for chemicals in drinking water.

As part of a program for evaluation of environmental contaminants in drinking water, risk assessments are being conducted to develop Public Health Goals (PHGs) for chemicals in drinking water, based solely on public health considerations. California's Safe Drinking Water Act of 1996 mandated the development of PHGs for over 80 chemicals by 31 December 1999. The law allowed these levels to be set higher or lower than federal maximum contaminant levels (MCLs), including a level of zero if data are insufficient to determine a specific level. The estimated safe levels and toxicological rationale for the first 26 of these chemicals are described here. The chemicals include alachlor, antimony, benzo[a]pyrene, chlordane, copper, cyanide, dalapon, 1,2-dichlorobenzene, 1,4-dichlorobenzene, 2,4-D, diethylhexylphthalate, dinoseb, endothall, ethylbenzene, fluoride, glyphosate, lead, nitrate, nitrite, oxamyl, pentachlorophenol, picloram, trichlorofluoromethane, trichlorotrifluoroethane, uranium and xylene(s). These risk assessments are to be considered by the State of California in revising and developing state MCLs for chemicals in drinking water (which must not exceed federal MCLs). The estimates are also notable for incorporation or consideration of newer guidelines and principles for risk assessment extrapolations.

Algorithms↗
PubMed2004

Chlorophenol exposure in harbor workers exposed to river silt aerosols.

OBJECTIVES: While dredging the river Elbe in the harbor of Hamburg, workers are potentially exposed to river silt aerosols containing organic compounds. The aim of this cross-sectional study was to determine the internal load of chlorophenols in exposed workers. METHODS: Eighty-four exposed workers and eighty-four unexposed office workers were examined. Urinary samples were analyzed for dichlorophenols, trichlorophenols, tetrachlorophenols, and pentachlorophenol (PCP). RESULTS: For exposed workers, more than 2/3 of the urinary samples were above detection limit for 2,5-dichlorophenol, 2,4/3,4-dichlorophenol, 2,4,6-trichlorophenol, and PCP. Harbor workers had significantly higher median levels of 2,5-dichlorophenol (0.6 vs. 0.4 microg/g creatinine) and PCP (1.4 vs. 1.0 microg/g creatinine) as compared to unexposed subjects. These differences remained statistically significant after adjustment for age, smoking habits, and fish consumption. CONCLUSION: Harbor workers in the harbor of Hamburg have a statistically significant higher internal load of chlorophenols than the general population. However, the internal load is within the range of exposure reported from the general population. Therefore, even though chlorophenols are found in the river silt these exposures do not seem to be the major source of the internal load among workers in the harbor of Hamburg.

Adult↗
PubMed2004

NMR parameters and geometries of OHN and ODN hydrogen bonds of pyridine-acid complexes.

In this paper, equations are proposed which relate various NMR parameters of OHN hydrogen-bonded pyridine-acid complexes to their bond valences which are in turn correlated with their hydrogen-bond geometries. As the valence bond model is strictly valid only for weak hydrogen bonds appropriate empirical correction factors are proposed which take into account anharmonic zero-point energy vibrations. The correction factors are different for OHN and ODN hydrogen bonds and depend on whether a double or a single well potential is realized in the strong hydrogen-bond regime. One correction factor was determined from the known experimental structure of a very strong OHN hydrogen bond between pentachlorophenol and 4-methylpyridine, determined by the neutron diffraction method. The remaining correction factors which allow one also to describe H/D isotope effects on the NMR parameters and geometries of OHN hydrogen bond were determined by analysing the NMR parameters of the series of protonated and deuterated pyridine- and collidine-acid complexes. The method may be used in the future to establish hydrogen-bond geometries in biologically relevant functional OHN hydrogen bonds.

Acids↗
PubMed1997

Sulfobutylether-beta-cyclodextrin-mediated capillary electrophoresis for separation of chlorinated and substituted phenols.

Cyclodextrin-mediated capillary electrophoresis has been developed for separation and analysis of chlorinated as well as substituted phenolic compounds. The procedure used a negatively charged sulfobutylether-beta-cyclodextrin (SB-betaCD) to effect differential partitioning of the phenols between the buffer and CD phases. In 50 mM phosphate buffer containing as low as 1 mM SB-betaCD, 25 phenolic compounds including 11 Environmental Protection Agency (EPA) priority phenols were separated with theoretical plate numbers well above 100,000, for 50 cm of effective length in most cases. An equilibrium complexation model was used for investigating the effect of pH as well as different cyclodextrin concentrations on the electrophoretic mobility. The cyclodextrin-mediated capillary electrophoresis system was also applicable for separating and quantifying the level of pentachlorophenol in contaminated soil samples.

Chlorophenols↗
PubMed2006

Human sulphotransferases are involved in the activation of aristolochic acids and are expressed in renal target tissue.

Use of herbal preparations containing Aristolochia species has led to progressive nephropathy and urothelial cancer in humans. Analysis of DNA adducts formed in human target tissues and studies in animal models have pointed out a major role of the secondary plant metabolites, aristolochic acids, in these effects. Only a minority of the users of Aristolochia-containing products developed nephropathy and cancer, suggesting differences in individual susceptibility. Differences in metabolic activation and inactivation frequently affect the susceptibility towards chemicals. Others have shown that the activation of aristolochic acids to DNA-reactive and mutagenic metabolites requires reduction of their aryl nitro group. The biological activity of numerous nitro- and aminoarenes, after appropriate phase I metabolism, is strongly enhanced in the presence of acetyltransferases or sulphotransferases (SULTs). In the present study, we demonstrate that expression of human SULTs in bacterial and mammalian target cells reinforces the mutagenic activity of aristolochic acids. Using Salmonella typhimurium TA1538 as the recipient organism, we identified the expression of all 12 human SULT forms. SULT1A1 led to the strongest increase in the mutagenicity of aristolochic acids. Some activation was also observed with SULT1B1, but not with the remaining forms. The role of SULT1A1 in the activation of aristolochic acids was corroborated using S. typhimurium TA100- and Chinese hamster V79-derived target cells engineered for expression of human SULT1A1 when compared with control cells. Furthermore, pentachlorophenol, an inhibitor of SULT1A1, strongly reduced the mutagenic effect of aristolochic acids in V79-hCYP2E1-hSULT1A1 cells. Moreover, we demonstrate that SULT1A1 and SULT1B1 are expressed in human kidney using immunoblot analysis, but their levels are substantially lower than in liver. Finally, we discuss the possibility that reactive sulphuric acid conjugates produced in other tissues are transferred to kidney and ureter.

Aged↗
PubMedDate not supplied

Response characteristics of an aquatic biomonitor used for rapid toxicity detection.

The response characteristics of an aquatic biomonitor that detects toxicity by monitoring changes in bluegill (Lepomis macrochirus Rafinesque) ventilatory and movement patterns were evaluated in single chemical laboratory studies at concentrations near the 96-h LC(50) concentration and at the EILATox-Oregon Workshop in sequential tests of multiple unknown samples. Baseline data collected prior to exposure allows each fish to serve as its own control. When at least 70% of exposed fish exhibit ventilatory or movement parameters significantly different from baseline observations, a group alarm is declared. In the laboratory studies, the aquatic biomonitor responded to the majority of chemicals at the 96-h lc(50) within an hour or less, although substantially higher response times were found for malathion and pentachlorophenol. Workshop tests of single chemical concentrations presented as blind samples were consistent with the laboratory test results. There were no alarms under control conditions in any test. Although data are limited, the aquatic biomonitor appears to respond more rapidly to chemicals causing membrane irritation, narcosis or polar narcosis than to acetylcholinesterase inhibitors or oxidative phosphorylation uncouplers. All four monitored parameters (ventilatory rate, cough rate, ventilatory depth and movement) contributed to identification of first alarms at acutely toxic levels. Understanding these response patterns can be useful in data interpretation for biomonitor applications such as surface water monitoring for watershed protection, wastewater treatment plant effluent monitoring or source water monitoring for drinking water protection.

Animals↗
PubMed2001

Effect of three chlorinated pesticides on hsromega stress gene in transgenic Drosophila melanogaster.

Expression of hsromega stress gene in the third-instar larvae of 951-lacZ2 (hsromega-lacZ having-844pb sequence) and 498-lacZ1 (hrsomega-lacZ having -498bp sequence) strains of Drosophila melanogaster at LC(50) and lower dietary concentrations of hexachlorocyclohexane (HCH) pentachlorophenol (PCP), and endosulfan was examined in relation to larval mortality by beta galactosidase activity, vital dye staining, and salivary gland polytene chromosome puffing. Our results showed that both HCH and PCP at lower concentrations evoked strong hsromega stress gene expression in the larval tissues while endosulfan did not. On the other hand, puffing data revealed that endosulfan at lower doses, induced well-developed puff at the resident site (93D) of the hsromega gene but the transgenic sites (30B in 951-lacZ2 and 44B in 498-lacZ1 strain) did not show any well-developed puff. Regression in hsromega stress gene expression in 951-lacZ2 strain at LC(50) concentrations of HCH and PCP after 48 h was concurrent with extensive tissue damage as evident by trypan blue staining. Similarly, strong hsromega expression was accompanied by insignificant trypan blue staining in the larval tissues of this strain after shorter duration of exposure (2-12 h) to these toxicants. Although endosulfan under similar experimental condition did not induce hsromega, strong trypan blue staining indicated extensive tissue damage after 48 h of exposure. The present study suggests that all the three toxicants pose cytotoxic potential to Drosophila. While protective role of this stress gene was evident at the initial stages of exposure, extensive tissue damage in the later stages of intoxication accompanied by autorepression of hsromega led to larval mortality. The study further suggests that -844bp upstream sequence of the gene is adequate for hsromega inducibility against HCH and PCP but not for endosulfan for which responsive elements may be searched further upstream.

Animals↗
PubMed1978

[Inhibition of chitin synthetase of Mucor rouxii in vitro by fungicides and other compounds].

Comparative investigations on the inhibition of chitin synthetase of Mucor rouxii revealed that in contrast to results obtained in vivo, only few fungicides and other compounds inhibit the enzyme in vitro. Besides the well-known effect of polyoxin D, an inhibition was demonstrated for terrazol, tridemorph, hinosan, and formulated preparations of dimilin (PH 60--40, 60--38). The latter preparations, however, showed growth inhibition also with fungal species which do not synthesize chitin and the pure compounds are ineffective. Inhibition by phospholipase C, unsaturated fatty acids, and the reversibility of the inhibition caused by terrazol after addition of procain-hydrochloride demonstrates that phospholipids are essential for the activity of the enzyme, whereas sterols seem to be ineffective. Action of trypsin, PCNB, pentachlorophenol, and some similar compounds results in significantly increased activity, which in the case of trypsin could be due to the hydrolysis of a protein inhibitor. Hinosan inhibits the enzyme indirectly in a still unexplored manner.

Antifungal Agents↗
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↗
PubMed2007

An electrospray membrane probe for the analysis of volatile and semi-volatile organic compounds in water.

A new membrane probe incorporating electrospray ionization (ESI) was designed, built and coupled to an ion trap mass spectrometer to detect low levels of semi-volatile organic compounds (SVOCs) in water. Similar to other membrane introduction mass spectrometry (MIMS) systems, the probe contains a capillary polydimethylsiloxane (PDMS) membrane to allow for the preferential permeation of small molecules but, in contrast, the interface uses a liquid/membrane/liquid interface rather than liquid/membrane/gas. The ESI source allows the probe to be operated at atmospheric pressure in positive or negative ionization mode and the lack of fragmentation in ESI allows for the simultaneous screening of many analytes with high sensitivity. The interface allows for the addition of additives to both the external and the internal liquid mobile phases to selectively improve permeation and/or the ionization efficiency of various classes of compounds. Characterization of the probe with methanol as the internal mobile phase showed that the signal for aniline optimized at 60 degrees C and an internal flow rate between 2-5 microL/min. The transfer of analyte through the membrane from water to methanol ensures a strong signal and robust electrospray for both positive and negative ion mode which is not typical when spraying pure water. Detection limits for aniline, pyridine and pentachlorophenol, and for the herbicides alachlor, atrazine, butachlor, metolachlor and simazine, were in the ppb to pptr range.

Environmental Monitoring↗
PubMed2001

Direct detection of polyaromatic hydrocarbons, estrogenic compounds and pesticides in water using desorption chemical ionisation membrane inlet mass spectrometry.

This paper describes the use of desorption chemical ionisation membrane inlet mass spectrometry (DCI-MIMS) for the detection of a broad range of common contaminants in water. In addition, we discuss the advantages/disadvantages of two different types of chemical ionisation reagent gases, i-butene (a Broensted acid reagent) and argon (a charge exchange reagent). We found that polyaromatic hydrocarbons was detectable at ppt levels, the estrogenic compounds diethyl phthalate and octylphenol at high ppt levels, steroid hormones at ppb levels, hydrophobic pesticides at low ppb levels, whereas hydrophilic pesticides and bisphenol A were not detectable at all. With the exception of the polyaromatic hydrocarbons and pentachlorophenol, none of the reported compounds have to our knowledge been detected previously by other MIMS systems. In most cases the Broensted acid reagent gave characteristic ions at high mass/charge ratio, whereas the charge exchange reagent gave less characteristic ions at low m/z ratio. However, the sensitivity was generally not as good with the Broensted acid reagent as with the charge exchange reagent, since the Broensted acid reagent, i-butene, gave a large chemical background.

Estrogens↗