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PubMed1993

Chemically bonded stationary phases that use synthetic hosts containing aromatic binding clefts: HPLC analysis of nitro-substituted polycyclic aromatic hydrocarbons.

The synthesis of hosts with improved binding affinities for nitroaromatic guests is described. Association constants for several host-guest complexes were measured in chloroform solution and ranged over three orders of magnitude. Two hosts were covalently linked to silica gel to produce chemically bonded stationary phases for HPLC. The use of these phases for HPLC analysis of nitro-substituted polycyclic aromatic hydrocarbons is discussed.

Chromatography, High Pressure Liquid↗
PubMed1990

Metabolic activation of the new tricyclic antidepressant tianeptine by human liver cytochrome P450.

Incubation of [14C]tianeptine (0.5 mM) with human liver microsomes and a NADPH-generating system resulted in the in vitro covalent binding of a tianeptine metabolite to microsomal proteins. This covalent binding required oxygen and NADPH. It was decreased by piperonyl butoxide (4 mM) by 81%, and SKF 525-A (4 mM) by 87%, two relatively non-specific inhibitors of cytochrome P450, and by glutathione (4 mM) by 70%, a nucleophile. Covalent binding was decreased by 54% in the presence of troleandomycin (0.1 mM), a specific inhibitor of the glucocorticoid-inducible cytochrome P450 IIIA3, but remained unchanged in the presence of quinidine (0.1 mM) or dextromethorphan (0.1 mM), two inhibitors of cytochrome P450 IID6. Preincubation with IgG antibodies directed against cytochrome P450 IIIA3 decreased covalent binding by 65% whereas either preimmune IgG or IgG antibodies directed against P450 IA1, an isoenzyme inducible by polycyclic aromatic compounds, exhibited no significant inhibitory effect. We conclude that tianeptine is activated by human liver cytochrome P450 into a reactive metabolite. This activation is mediated in part by glucocorticoid-inducible isoenzymes but not by P450 IID6 (the isoenzyme which oxidizes debrisoquine) nor by P450 IA1 (an isoenzyme inducible by polycyclic aromatic compounds). The predictive value of this study regarding possible idiosyncratic and immunoallergic reactions in humans remains unknown.

Antidepressive Agents, Tricyclic↗
PubMed1986

Bacterial mutagenicity and chemical analysis of polycyclic aromatic hydrocarbons and some nitro derivatives in environmental samples collected in West Germany.

Snow and air particulate samples collected in Upper Frankonia, Federal Republic of Germany, have been analyzed for nitro-polycyclic aromatic hydrocarbons (PAH) and PAH content. A novel clean-up technique has been developed enabling interfering organochlorine environmental contaminants to be removed prior to analysis of the hydrocarbons by GC-MS. Mass fragmentation patterns are presented for 1-nitropyrene, 6-nitrobenzo(a)pyrene, 6-nitrochrysene, and 3-nitrofluoranthene. The level of these compounds found in air samples was in the range of 0.2-2.0 ng.m-3 with the exception of 6-nitrobenzo(a)pyrene, which was not detected. This compares with PAH values of between 1 and 6 ng.m-3. The freshly fallen snow sample collected at the side of a motorway had no detectable PAHs or nitro-PAHs. Parallel studies on the bacterial mutagenicity of the collected air samples using Salmonella typhimurium TA98 and TA100 in the presence and absence of aroclor-induced rat liver "S9" revealed both "direct" and "indirect" activity. Larger numbers of mutants were induced in the presence of S9 than in its absence. The snow sample was devoid of mutagenic activity. These studies show the utility of the biological approach to screen environmental samples prior to expensive and time-consuming chemical analysis.

Air Pollutants↗
PubMed1983

Detection of mutagenic/carcinogenic compounds in unused and used motor oils.

The discharge of used motor oils in the environment poses public health problems because of the mutagenic/carcinogenic compounds in them. Among these hazardous chemicals, polycyclic aromatic hydrocarbons (PAH) are of particular interest since the carcinogenic properties of some of them are known. The authors have applied the Salmonella/microsome test, coupled with two preparation methods of samples, to motor oils of different brands, both before and after use in car petrol engines. A PAH determination method was also studied. The results showed the unused motor oils to be nonmutagenic and to contain traces of PAH, while the used motor oils of the samples taken according to both preparation methods were highly mutagenic and contained a much higher quantity of mutagenic/carcinogenic PAH.

Automobiles↗
PubMed2005

Metabolic activation of polycyclic and heterocyclic aromatic hydrocarbons and DNA damage: a review.

Polycyclic aromatic hydrocarbons (PAHs) and heterocyclic aromatic compounds (HACs) constitute a major class of chemical carcinogens present in the environment. These compounds require activation to electrophilic metabolites to exert their mutagenic or carcinogenic effects. There are three principal pathways currently proposed for metabolic activation of PAH and HAC: the pathway via bay region dihydrodiol epoxide by cytochrome P450 enzymes (CYPs), the pathway via radical cation by one-electron oxidation, and the ortho-quinone pathway by dihydrodiol dehydrogenase (DD). In addition to these major pathways, a brief description of a minor metabolic activation pathway, sulfonation, for PAHs that contain a primary benzylic alcoholic group or secondary hydroxyl group(s) is included in this review. The DNA damages caused through the reactive metabolites of PAH/HAC are described involving the DNA covalent binding to form stable or depurinating adducts, the formation of apurinic sites, and the oxidative damage. The review emphasizes the chemical/biochemical reactions involved in the metabolic processes and the chemical structures of metabolites and DNA adducts.

Animals↗
PubMed1995

[Risk for the Rostock water supply from the Warnov river by an old deposit at Schwann?].

Accidents of the city gasworks in the end of the fifties at Schwaan, a small town south of Rostock, resulted in an emission of tar and waste water into the river Warnow, from which the city of Rostock is supplied with drinking water about 20 km downstream. The tar contaminated river sediment (old deposit) covering an area of about 200 m2 has a high pollutant inventory: Steam-distillable phenolic compounds 407 mg/kg in the fresh sediment, polycyclic aromatic hydrocarbons (PAH) 400 to 1100 micrograms/l in the aqueous eluate. The mutagenic potential was detected by the AMES-test. As shown by PAH determinations there were no other pollutant sources in the catchment area, in the tributaries or on other places of the river. The mean PAH concentrations of the river Warnow and his tributaries during 1991 to 1994 were found to be in the range lower than 10 ng/l. Further investigations showed a continuous emission of PAH from the tar laugh in small amounts. An additional emission of pollutants (PAH) and their transportation in the river is expected in the case of sediment disturbances. This emission and their possible consequences are difficult to estimate, even though the seston and the humic substances content of the river seems to reduce the PAH risk. Concluding from our results the probability is very low that pollutants were transported downstream to Rostock and pass the water works but may not totally be excluded. Nevertheless from the viewpoint of care a removal of the old deposit is necessary.

Fresh Water↗
PubMed1996

Human cell mutagenicity of oxygenated, nitrated and unsubstituted polycyclic aromatic hydrocarbons associated with urban aerosols.

Polycyclic aromatic compounds (PAC) are ubiquitous pollutants in urban air that may pose risks to human health. In order to better assess the health risks associated with this class of compounds, a total of 67 PAC that either have been identified (55) or are suspected to be present (12) in urban aerosol samples were tested for mutagenicity in a forward mutation assay based on human B-lymphoblastoid cells. The cell line used (designated h1A1v2) constitutively expresses the cytochrome P4501A1, which is known to be necessary for the metabolism of many promutagens. The PAC tested included 39 polycyclic aromatic hydrocarbons (PAH). 19 oxygen-containing PAH (oxy-PAH) and nine NO2-substituted PAH (nitro-PAH). A total of 26 PAH were mutagenic. In comparing the minimum mutagenic concentrations of the mutagenic PAH with that of benzo[a]pyrene (B[a]P) it was found that dibenzo[a,l]pyrene (DB[al]P), cyclopenta[c,d]pyrene (CPP), naphtho[2,1-a]pyrene, dibenzo[a,e]pyrene (B[a]P) and 1-methylbenzo[a]pyrene were 24 +/- 21, 6.9 +/- 4.2, 3.2 + 3.0, 2.9 +/- 2.9 and 1.6+/- 1.4 times, respectively, more mutagenic than B[a]P, and that dibenzo[a,k]fluoranthene and B[a]P were approximately equally mutagenic. The 19 other mutagenic PAH were between approximately 2 and approximately 1800 times less mutagenic than B[a]P. Of the oxy-PAH tested only phenalenone, 7H-benz[d,e]anthracen-7-one, 3-nitro-6H-dibenzo[b,d]pyran-6-one, cyclopenta[c,d]pyren-3(4H)-one, 6H-benzo[c,d]pyren-6-one (BPK) and anthanthrenequinone were mutagenic; however, with the exception of BPK, these were over 50 times less active than B[a]P, BPK was approximately 3 times less active than B[a]P. Seven of the nitro-PAH were mutagenic including 9-nitroanthracene, 1-nitropyrene, 2-nitrofluoranthene, 3-nitrofluoranthene, 1,3-dinitropyrene, 1,6-dinitropyrene (1,6-DNP) and 1,8-dinitropyrene. 1,6-DNP was approximately 4 times less active than B[a]P; the six other mutagenic nitro-PAH were between 20 and 380 times less active than B[a]P. These results are discussed in terms of their relevance for determining the most important mutagens in ambient air. Based on reported concentrations of PAC in ambient aerosols, it is possible that CPP, DB[ae]P, DB[al]P and BPK could account for a greater proportion of the mutagenicity than B[a]P in some aerosols.

Aerosols↗
PubMed1996

Developmental toxicity study in rats exposed dermally to clarified slurry oil for a limited period of gestation.

Clarified slurry oil (CSO, CAS number 64741-62-4), a refinery stream produced by processing crude oil, is a developmental toxicant when administered dermally throughout gestation to pregnant rats. The manifestations of developmental toxicity observed included embryolethality and growth retardation; evidence of teratogenicity was limited, and not conclusive. The present study was undertaken to further explore the teratogenic potential of CSO. In an attempt to limit embryolethality and thereby promote detection of terata, CSO was administered once daily for a limited period of gestation [gestation days (GD) 9-12], via dermal application, to pregnant Sprague-Dawley rats at doses of 0, 10, 100, and 1000 mg/kg. All animals were sacrificed on GD 20. Detailed examination of the dams was performed. Due to the screening nature of this investigation, fetal evaluations were limited to body weight measurements, external examinations, and evaluation of select visceral endpoints. In the dams exposed to CSO, significant decreases in body weight [absolute and gain (GD 9-13, GD 0-20)] and in the amount of food consumed were observed at 100 and 1000 mg/kg. Additional evidence of maternal toxicity observed at 1000 mg/kg included decreased absolute and relative thymus weights, increased absolute and relative liver weights, and aberrant serum chemistry. Ingestion of the test material was evident at the high dose. Developmental toxicity was observed at 1000 mg/kg and included increased embryolethality, decreased body weight, and anomalous development (cleft palate, brachydactyly, edema). Although a low incidence of abnormal fetal development was observed at 100 mg/kg, it was not conclusive that the alterations were due to CSO exposure. It is likely that three to seven-ring polycyclic aromatic compounds present in CSO were responsible for the toxic effects observed.

Administration, Cutaneous↗
PubMed2001

Electrochemical methods for monitoring of environmental carcinogens.

The use of modern electroanalytical techniques, namely differential pulse polarography, differential pulse voltammetry on hanging mercury drop electrode or carbon paste electrode, adsorptive stripping voltammetry and high performance liquid chromatography with electrochemical detection for the determination of trace amounts of carcinogenic N-nitroso compounds, azo compounds, heterocyclic compounds, nitrated polycyclic aromatic hydrocarbons and aromatic and heterocyclic amines is discussed. Scope and limitations of these methods are described and some practical applications based on their combination with liquid-liquid or solid phase extraction are given.

Azo Compounds↗
PubMed1994

Atmospheric chemistry of gas-phase polycyclic aromatic hydrocarbons: formation of atmospheric mutagens.

The atmospheric chemistry of the 2- to 4-ring polycyclic aromatic hydrocarbons (PAH), which exist mainly in the gas phase in the atmosphere, is discussed. The dominant loss process for the gas-phase PAH is by reaction with the hydroxyl radical, resulting in calculated lifetimes in the atmosphere of generally less than one day. The hydroxyl (OH) radical-initiated reactions and nitrate (NO3) radical-initiated reactions often lead to the formation of mutagenic nitro-PAH and other nitropolycyclic aromatic compounds, including nitrodibenzopyranones. These atmospheric reactions have a significant effect on ambient mutagenic activity, indicating that health risk assessments of combustion emissions should include atmospheric transformation products.

Air Pollutants↗
PubMed2004

Alkene substituents for selective activation of endo-regioselective polyepoxide oxacyclizations.

The presence of an alkenyl substituent on the terminal epoxide of a polyepoxide substrate enhances the yield of all-endo-regioselective tandem oxacyclization to trans-syn-trans-fused polycyclic ethers. For a substrate in which the epoxide and alkene functional groups are separated by two methylene substituents, a novel bromonium ion-induced endo-regioselective cyclization to bromooxepane is also described. [reaction: see text]

Alkenes↗
PubMed1984

[Effect of dose fractionation on the carcinogenicity of chemical substances].

Interrelations between single and total doses of chemical carcinogens are considered. On the basis of the data published and the author's own works a conclusion is drawn on the single dose as a decisive factor determining the organotropism (cytotropism) of certain pluripotential carcinogens (DMNA, DENA, DMH). Fractionation of the dose enhances the effect of polycyclic aromatic hydrocarbons, probably decreases the effect of directly acting carcinogens. Tumours of different histogenesis may respond to the dose fractionation in a different way.

1,2-Dimethylhydrazine↗
PubMed1978

Potentially carcinogenic species emitted to the atmosphere by fossil-fueled power plants.

The identities and physicochemical characteristics of potentially carcinogenic species emitted to the atmosphere by fossil-fueled power plants are presented and discussed. It is pointed out that many so-called carcinogens are preferentially concentrated on the surface of respirable fly ash particles thus enabling them to come into intimate contact with lung tissues when inhaled. Relatively little information is available about the identities of particulate polycyclic organic compounds whose emission from coal fired power plants may well be substantially greater than hitherto supposed. The importance of chemical changes, which several species may undergo following emission (but prior to inhalation) in determining their potential carcinogenic impact, is stressed.

Air Pollutants↗
PubMed1998

Feasibility of using prokaryote biosensors to assess acute toxicity of polycyclic aromatic hydrocarbons.

The aim of this study was to assess the acute toxicity of polycyclic aromatic hydrocarbons using lux-marked bacterial biosensors. Standard solutions of phenanthrene, pyrene and benzo[a]pyrene were produced using 50 mM hydroxpropyl-beta-cyclodextrin solution which contained each respective polycyclic aromatic hydrocarbon at 6.25 times the aqueous solubility limit of the compound. The polycyclic aromatic hydrocarbon solutions were incubated with each of the biosensors for 280 min and the bioluminescence monitored every 20 min. Over the incubation time period, there was no significant decrease in bioluminescence in any of the biosensors tested with the exception of Rhizobium leguminosarum biovar trifolii TA1 luxAB. In this series of incubations, there was a dramatic increase in bioluminescence in the presence of phenanthrene (2.5 times) and benzo[a]pyrene (3 times) above that of the background control (biosensor without polycyclic aromatic hydrocarbon) after 20 min. Over the next 3 h, bioluminescence decreased to that of the control. An ATP assay was carried out on the biosensors to assess if uncoupling of the oxidative phosphorylation mechanisms in the respiratory chain of the cells had occurred. However, it was found that the polycyclic aromatic hydrocarbons had no effect on the organisms indicating that there was no uncoupling. Additionally, mineralisation studies using 14C-labelled polycyclic aromatic hydrocarbons showed that the biosensors could not mineralise the compounds. This study has shown that the three polycyclic aromatic hydrocarbons tested are not acutely toxic to the prokaryotic biosensors tested, although acute toxicity has been shown in other bioassays. These results question the rationale for using prokaryote biosensors to assess the toxicity of hydrophobic chemicals, such as polycyclic aromatic hydrocarbons.

Adenosine Triphosphate↗
PubMed1993

Detection and comparison of DNA adducts after in vitro and in vivo diesel emission exposures.

Development of methods to evaluate certain classes of polycyclic aromatic compounds (PAC) detected in complex mixtures to which humans are exposed would greatly improve the diagnostic potential of 32P-postlabeling analysis. Identification of DNA adduct patterns or specific exposure-related marker adducts would strengthen associations between observed DNA adducts and exposures to different environmental pollutants (e.g., kerosene, cigarette smoke, coke oven, and diesel). We have compared diesel-modified DNA adduct patterns in various in vitro and in vivo rodent model systems and compared them to DNA reactive oxidative and reductive metabolites of 1-nitropyrene. The formation of nitrated polycyclic aromatic hydrocarbon (nitrated PAH) DNA adducts, derived from the metabolism of diesel extract constituents, was enhanced relative to other PAH-derived DNA adducts via xanthine oxidase-catalyzed nitroreduction. These adducts were detectable only by the butanol extraction version of the postlabeling analysis. Five major DNA adducts were detected in human lymphocytes treated in vitro with diesel extract. A major adduct detected in human lymphocytes treated in vitro with diesel extract comigrated with a major adduct detected in lymphocyte DNA treated with benzo[a]pyrene (BaP) alone. Other adducts that co-migrated with the major BaP-derived adducts were detected in skin and lung DNA isolated from rodents topically treated with (50 mg) diesel extract and the major adduct detected in calf thymus DNA treated with rat liver S9 and diesel particle extract. Postlabeling of lung DNA isolated from rodents exposed via lung inhalation for 24 months to diesel combustion emissions resulted in the formation of a major nuclease-P1-sensitive DNA adduct that did not co-migrate with the major BaP-diol epoxide adduct.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1988

Degradation of polycyclic aromatic hydrocarbons and aromatic heterocycles by a Pseudomonas species.

Enrichment cultures were established with the aromatic fraction of a crude oil and screened for aromatic-degrading pseudomonads, using a sprayed plate technique. One isolate identified as Pseudomonas sp. HL7b was chosen for further study because it oxidized several polycyclic aromatic hydrocarbons and aromatic heterocycles without an apparent lag. Using capillary gas chromatography, spectrophotometry, and radiorespirometry, it was found to be capable of mineralizing and (or) oxidizing a wide range of polycyclic aromatic hydrocarbons, S-, N-, and O-heterocyclic analogues, and alkyl polycyclic aromatic hydrocarbons, but not aliphatic hydrocarbons. The isolate displayed two colonial morphologies which correlated with variation in degradative phenotype and hydrophobicity as measured by polystyrene adherence. Four cryptic plasmids were observed in both colonial types. Pseudomonas sp. HL7b degraded dibenzothiophene co-metabolically by a recognized pathway, but this degradation was constitutive, rather than inducible as reported for other bacteria.

Biodegradation, Environmental↗
PubMed1994

Mutagenic and carcinogenic significance and the possible induction of lung cancer by nitro aromatic hydrocarbons in particulate pollutants.

Studies of genotoxicity and carcinogenicity of nitro aromatic hydrocarbons focus on their high mutagenicity for bacteria and mammalian cells. Nitrobenzo[a]pyrenes (NBPs) and related nitroazaarenes also are extraordinarily mutagenic. 3-Nitro-6-azabenzo[a]pyren-N-oxide was found to be a more potent mutagen than 1,8-dinitropyrene. Mutagenicity of NBPs was associated with the position of substitution of the nitro function when nitrogen dioxide (NO2) was substituted at the third position on the benzo[a]pyrene (BP) structure, as in 3,6-dinitrobenzo[a]pyrene but not in 1,6-diNBP. The NBPs were reduced by a rat liver postmitochondrial fraction to nitroso- and subsequently to amino-derivatives. Therefore, tumoral action in rats was induced at significant levels by subcutaneous injection of 3,6-diNBP, but no tumors were observed in rats given 1,6-diNBP. Carcinogenic nitropyrenes were detected in the resected lung of a patient with lung cancer. It is suggested that the presence of nitropyrenes and the resulting tumor were due to exposure to by-products of combustion of heavy oil. The patient was a nonsmoker and farmer who had bred chickens for 40 years. He used heavy oil for heating the chicken house. Similarly, a group of Chinese people at high risk of developing lung cancer was selected to determine the initiator of lung cancer. Lung cancers were obtained from six Chinese female nonsmokers who were living in Fuyuan County, China. Polycyclic aromatic hydrocarbons were detected in resected lung specimens; they were benzo[k]fluoranthene, BP, benzo[g,h,i]perylene, and pyrene. These cases were associated with exposure to soot from combustion of coal usually used for heating and cooking indoors.

Adult↗