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PubMedDate not supplied

Evaluation of the dermal carcinogenicity of lubricant base oils by the mouse skin painting bioassay and other proposed methods.

Lubricant base oils are petroleum products that are predominantly derived from the vacuum distillation of crude oil. Various types of refinement can be employed during the manufacturing process, and evidence suggests that certain of the associated process streams produce skin cancer. Polycyclic aromatic compounds (PACs), some of which are considered as the causative agents, are removed, concentrated or chemically converted during the refinement process. In order to understand the effects of various types of refinement processes on carcinogenic potential, 94 oils were evaluated in the mouse epidermal cancer bioassay. This Exxon database is unique, because of the wide range of crude oils and processing histories represented. Seven processing history classifications are described, and conclusions concerning the impacts of each refinement process on dermal carcinogenicity are discussed. This research also included an evaluation of selected biological and chemical test methods for predicting carcinogenic potential. These included a modified version of the Ames test for mutagenicity, as well as analytical characterizations of the polycyclic aromatic structures in the oils. For classification purposes, a sample was considered to be carcinogenic if it resulted in the production of two or more tumor-bearing animals (in test groups of either 40 or 50 animals). The modified Ames test was considered to be positive if the mutagenicity index was > or = 2.0, and PAC analyses were similarly designated as positive or negative according to proposed guidelines. All of the alternative test methods showed similar agreement with dermal carcinogenicity bioassay data; concordance values were > or = 80%. However, each test was incorrect in ca. 10%-20% of the cases evaluated.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMedDate not supplied

Separation of 32P-postlabeled DNA adducts of polycyclic aromatic hydrocarbons and nitrated polycyclic aromatic hydrocarbons by HPLC.

The 32P-postlabeling assay, thin-layer chromatography, and reverse-phase high-pressure liquid chromatography (HPLC) were used to separate DNA adducts formed from 10 polycyclic aromatic hydrocarbons (PAHs) and 6 nitrated polycyclic aromatic hydrocarbons (NO2-PAHs). The PAHs included benzo[j]fluoranthene, benzo[k]fluoranthene, indeno[1,2,3-cd]pyrene, benzo[a]pyrene, chrysene, 6-methylchrysene, 5-methylchrysene, and benz[a]anthracene. The NO2-PAHs included 1-nitropyrene, 2-nitrofluoranthene, 3-nitrofluoranthene, 1,6-dinitropyrene, 1,3-dinitropyrene, and 1,8-dinitropyrene. Separation of seven of the major PAH-DNA adducts was achieved by an initial PAH HPLC gradient system. The major NO2-PAH-DNA adducts were not all separated from each other using the initial PAH HPLC gradient but were clearly separated from the PAH-DNA adducts. A second NO2-PAH HPLC gradient system was developed to separate NO2-PAH-DNA adducts following one-dimensional TLC and HPLC analysis. HPLC profiles of NO2-PAH-DNA adducts were compared using both adduct enhancement versions of the 32P-postlabeling assay to evaluate the use of this technique on HPLC to screen for the presence of NO2-PAH-DNA adducts. To demonstrate the application of these separation methods to a complex mixture of DNA adducts, the chromatographic mobilities of the 32P-postlabeled DNA adduct standards (PAHs and NO2-PAHs) were compared with those produced by a complex mixture of polycyclic organic matter (POM) extracted from diesel emission particles. The diesel-derived adducts did not elute with the identical retention time of any of the PAH or NO2-PAH standards used in this study. HPLC analyses of the NO2-PAH-derived adducts (butanol extracted) revealed the presence of multiple DNA adducts.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1993

32P-postlabeling analysis of DNA adduct formation and persistence in English sole (Pleuronectes vetulus) exposed to benzo[a]pyrene and 7H-dibenzo[c,g]carbazole.

The formation and persistence of benzo[a]pyrene (BaP)- and 7H-dibenzo[c,g]-carbazole (DBC)-DNA adducts in liver of English sole (Pleuronectes vetulus) were investigated. BaP is a putative hepatocarcinogen in English sole based on its ability to induce formation of preneoplastic foci, while DBC is a hepatocarcinogen in mammals but whose carcinogenicity in fish is not known. English sole liver was sampled from 2 h through 84 days after a single intermuscular injection of a BaP and DBC mixture (100 mumol of each/kg body wt.), and DNA adduct levels were measured by the nuclease P1 version of the 32P-postlabeling assay. The major BaP adducts detected were from binding of BaP-7,8-diol-9,10-epoxide to DNA, whereas multiple uncharacterized DBC-DNA adducts were detected. Total adduct levels for both BaP and DBC reached a maximum at 2 days post exposure. The levels of DBC-DNA adducts were greater than the levels of BaP adducts at all time points and increased more rapidly than did the levels of BaP-DNA adducts. The DBC to BaP adduct ratio was 33 +/- 8.8 at 2 h and declined to 4.2 +/- 0.48 by 12 h post exposure. From 2 to 28 days, the levels of both BaP and DBC adducts declined with apparent half-lives of 11 and 13 days, respectively. There was no apparent decline from 28 to 84 days in the levels of the remaining BaP or DBC adducts; these persistent adducts represented 32 and 36% of maximum levels, respectively. These results provide the first data on the kinetics of adduct formation and removal of a carcinogenic nitrogen-containing polycyclic aromatic compound in fish. The results showing greater binding and similar persistence of DBC-DNA adducts compared to BaP-DNA adducts suggest that DBC may be hepatotoxic and potentially carcinogenic in English sole. In a separate experiment, the effect of multiple doses of BaP (30 mumol/kg body wt.) on the levels of hepatic BaP-DNA adducts showed that adduct levels increased linearly (r = 0.815, P = 0.0007) with 5 successive doses administered at 2 day-intervals and sampled 2 days after the last dose. The persistence of both BaP-DNA and DBC-DNA adducts in liver, together with the increase in BaP-DNA adducts in English sole exposed to successive doses of BaP, suggest that hepatic xenobiotic-DNA adducts in English sole are molecular dosimeters of relatively longterm environmental exposure to genotoxic polycyclic aromatic compounds.

Animals↗
PubMed1981

Nitrated polycyclic aromatic hydrocarbons: potent bacterial mutagens and stimulators of DNA repair synthesis in cultured human cells.

Ten polycyclic aromatic hydrocarbons (PAHs), viz. anthracene pyrene, chrysene, perylene, fluoranthene, benzo[a]pyrene, benzo[a]pyrene, benz[a]anthracene, benzo[ghi]perylene, benzo[k]fluoranthene, have been nitrated using concentrated nitric acid and the crude nitrated mixture examined for biological activity. All the nitro PAHs examined were mutagenic to Salmonella typhimurium in the absence of a rat liver preparation. Addition of Aroclor-1254 induced liver had little effect on mutagenicity. Mutagenic potency differed for the various nitrated mixtures with nitrated pyrene and nitrated fluoranthene the most potent and nitrated anthracene the least potent. Both frame-shift and base-substitution mutations were induced by the nitrated PAHs. The nitrated PAHs were also able to induce DNA repair synthesis in cultured HeLa cells in the absence of liver, indicating that these cells have the necessary enzymes to activate nitro PAHs. Potency again varied from compound to compound with nitrated pyrene appearing to be the most active. Isolation of individual components from the crude nitrated mixtures has not been carried out in this study. In view of the possible wide-spread distribution of nitrated PAHs in the environment further work is required to assess the carcinogenic potency of these compounds which possibly pose a risk to man.

Animals↗
PubMed1986

Xanthine oxidase-catalyzed DNA binding of dihydrodiol derivatives of nitro-polycyclic aromatic hydrocarbons.

Xanthine oxidase, a mammalian nitroreductase, catalyzed the covalent binding of a series of nitro-polycyclic aromatic hydrocarbons (nitro-PAHs) trans-dihydrodiols to DNA. Some of the trans-dihydrodiols bound to DNA to a greater extent than their parent nitro-PAHs; however, when the dihydrodiol moiety was peri to the nitro substituent low levels of binding were observed. These data illustrate that ring-oxidation and hydrolysis of nitro-PAHs to their trans-dihydrodiols followed by nitroreduction is a potential metabolic pathway leading to DNA adducts in mammals.

Animals↗
PubMed1994

Correlation of systemic and developmental toxicities with chemical component classes of refinery streams.

Refinery streams are complex mixtures, but of a relatively few homologous series of hydrocarbons (paraffins, olefins, naphthenics, and aromatics). Studies were performed to determine if systemic and developmental toxicity were related to the presence and levels of certain classes of refinery stream components. We have performed systemic toxicology studies in the rat on 13 refinery streams: Clarified Slurry Oil, Coker Light Gas Oil, Distillate Aromatic Extract, Heavy Atmospheric Gas Oil, Heavy Coker Gas Oil (from three refineries), Heavy Vacuum Gas Oil, Light Catalytically Cracked Naphtha, Light Cycle Oil, Syntower Bottoms, Vacuum Tower Overhead, and Visbreaker Gas Oil. Rats were exposed via repeated dermal administration (daily) at several dose levels. Developmental toxicology studies were performed on these same streams with the following exceptions: only two Heavy Coker Gas Oils were tested and Visbreaker Gas Oil was not tested. End points for systemic toxicity (13-week) studies included skin irritation, body and organ weights, hematology, and serum chemistry; for developmental toxicity studies some of these same end points (excluding hematology) were considered, but they also included resorption and fetal body weight. In general, toxicity was correlated with concentrations of polycyclic aromatic compounds (PAC) composed of 3, 4, 5, 6, and/or 7 rings (decreased thymus weight, increased liver weight, aberrant hematology and serum chemistry, increased incidence of resorption, decreased fetal body weight), PAC containing nonbasic nitrogen heteroatoms (increased mortality, decreased body weight, decreased thymus weight, increased liver weight, decreased hemoglobin content and hematocrit level, decreased fetal body weight), and/or PAC containing sulfur heteroatoms (decreased red blood cell and platelet counts, increased sorbitol dehydrogenase.)(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1976

Inducible monooxygenase activities and 3-methyl-cholanthrene-initiated tumorigenesis in mouse recombinant inbred sublines.

The induction of a certain group of hepatic monooxygenase activities by polycyclic aromatic compounds is regulated by the same locus or gene cluster controlling the formation of cytochrome P1-450 (P-448) in mice. Certain inbred strains of mice are "responsive" (Ahb) to such induction, whereas others are "nonresponsive" (Ahd). A pair of closely related sublines that differ with respect to the Ah locus (for aromatic hydrocarbon responsiveness) were used to identify or confirm the pleiotropic effects of this gene. The lines were derived by sibling-mating without selection from (C57L/J x AKR/J)F2 mice; the two sublines were separated at the F12 generation. Ten microsomal monooxygenase activities and one cytosol enzyme activity known to be associated with the Ah locus were similarly associated with cytochrome P1-450 formation in these recombinant inbred sublines as well. Nine additional hepatic monooxygenase activities studied were found not to be associated with the Ah locus; certain of these activities were increased slightly, following treatment of nonresponsive as well as responsive mice with polycyclic aromatic compounds. The Ahb-containing subline was highly susceptible to 3-methylcholanthrene-induced subcutaneous sarcomas, whereas the Ah-d-containing subline was relatively resistant. These results emphasize the potential importance of this particular enzyme for the study of coordinated regulation in mammals.

Animals↗
PubMedDate not supplied

Analysis of nitro-PAHs in food matrices by on-line reduction and high performance liquid chromatography.

Two different approaches to the analysis of nitrated polycyclic aromatic hydrocarbons (nitro-PAHs) in food samples are presented, based on liquid chromatography with fluorescence detection and gas chromatography with a mass selective detector as the alternative method. For the HPLC analysis the nitro-PAHs at trace level concentrations are efficiently reduced to primary aromatic amines on a catalyst column packed with 5 microns alumina coated with platinum and rhodium. The particulate extraction/fractionation procedure is discussed and the results of both methods are compared. The concentrations of seven nitro-PAHs in grilled and smoked food are presented.

Animals↗
PubMedDate not supplied

Standard reference materials for chemical and biological studies of complex environmental samples.

Standard Reference Materials (SRMs) from the National Institute of Standards and Technology (NIST) are often used in methods development and interlaboratory comparison studies since they are homogeneous and readily available to the scientific community. SRM 1649 (urban dust/organics), SRM 1650 (diesel particulate matter), and SRM 1597 (complex mixture of polycyclic aromatic hydrocarbons from coal tar) are three environmental samples which have been used by the scientific community for these purposes. These SRMs were originally developed to assist laboratories in validating analytical procedures for the determination of polycyclic organic compounds in complex mixtures. In addition, these SRMs have been valuable for the comparison of methodologies for bacterial bioassays and the development of bioassay-directed fractionation and bioassay-directed chemical analysis techniques. Most recently these SRMs were chosen for use as test samples in a collaborative study coordinated by the World Health Organization--International Programme on Chemical Safety. This paper provides a summary of much of the work to date (published and unpublished) on the chemical and biological characterization of these three SRMs. Information regarding the availability of other NIST SRMs that might be useful for these types of studies are provided also.

Air Pollutants↗
PubMed1993

Inducer-dependent transcriptional activation of the P4501A2 gene in vivo and in isolated hepatocytes.

In vitro nuclear run-on transcription analysis using probes directed against different regions of CYP1A2 revealed that the 70-100-fold induction of CYP1A2 mRNA by polycyclic aromatic compounds is associated with a corresponding increase in the transcriptional activation of this gene in rat liver. Probes from regions of the 1st, 2nd, and 4th introns detected approximately 50-100-fold higher CYP1A2 run-on transcription in liver nuclei from inducer-treated animals than in nuclei from untreated animals. The run-on signals from untreated rats were 3-5-fold above background signals. Additional experiments using single-stranded DNA probes and a probe from a region 5' to the CYP1A2 transcription start site revealed that the inducer-dependent transcripts were colinear with the CYP1A2 mRNA and that they did not result from read through of an initiation event 5' to CYP1A2. Run-on transcription analyses were also carried out with nuclei from isolated hepatocytes using the same series of probes spanning CYP1A2. These analyses indicated that the inducer-dependent accumulation of CYP1A2 mRNA in hepatocytes is associated with at least a 20-fold increase in CYP1A2 transcription. In contrast to liver and hepatocytes, these probes failed to detect run-on transcripts from kidney nuclei, indicating that the lack of CYP1A2 mRNA in this tissue is due to the lack of transcriptional activation of this gene by polycyclic aromatic compounds.

Animals↗
PubMed2006

Retrospective monitoring of synthetic musk compounds in aquatic biota from German rivers and coastal areas.

The polycyclic musk compounds HHCB (Galaxolide) and AHTN (Tonalide) are commonly used as synthetic fragrances in personal care products and household cleaners. These and other synthetic musk fragrances were quantified in different aquatic samples from the German Environmental Specimen Bank (ESB). While HHCB and AHTN were found in almost all samples, most of the other musk fragrances were detected only in a few samples and mostly at lower concentration levels. Blue mussels from the North Sea showed varying levels of 0.5-1.7 ng g(-1) ww for HHCB and 0.4-2.5 ng g(-1) ww for AHTN (ww, wet weight) in the period from 1986 to 2000, while blue mussels from the Baltic Sea were only slightly contaminated with synthetic musk fragrances. Lipid weight-related concentrations of synthetic musk compounds in blue mussels were higher than in eelpout muscles, bladder wrack and herring gull eggs. In comparison to the marine specimens, muscles of bream from German rivers had higher concentrations of HHCB and AHTN. The ranges of HHCB and AHTN concentrations in bream from the Elbe River were 545-6400 ng g(-1) lw and 48-2130 ng g(-1) lw, respectively (lw, lipid weight; five sampling sites, period 1993-2003). In the Rhine River, HHCB and AHTN levels of bream muscles were highest at the Iffezheim site (up to 9750 ng g(-1) lw HHCB, 1998). Even higher synthetic musk levels were detected in bream from the rivers Saale and Saar. In recent years, levels of both compounds determined in bream from most sampling sites have decreased from maximum values in the 1990s. As the concentrations of AHTN have decreased faster, the ratio of HHCB to AHTN increased from 2-4 in the 1990s to 10-20 in recent years.

Animals↗
PubMed1987

Predicting the carcinogenic potential of environmental nitropyrenes.

Nitrated polycyclic aromatic hydrocarbons (nitroarenes) constitute a large group of anthrapogenic environmental contaminants. Some members of the group are mutagenic and genotoxic in a wide spectrum of systems while others are either mutagenic only in Salmonella typhimurium or devoid of activity altogether. Additionally, some nitroarenes are uniformly carcinogenic in rodents while others are not. In view of the logistic and economic problems involved in preparing large quantities of individual nitroarenes in pure (greater than 99.5%) form and assaying them for carcinogenicity in animals, we have analyzed the results that nitropyrenes and related chemicals yield in short-term tests by CPBS, the Carcinogen Prediction, and Battery Selection method, and demonstrate that CPBS classifies them correctly with respect to carcinogenicity.

Animals↗
PubMedDate not supplied

Specific crystal chemical interactions between carcinogenic aromatic compounds and cholesterol.

Polycyclic aromatic hydrocarbons and aromatic amines exercise a highly specific influence on the crystallization of cholesterol. The strength of these non-covalent, presumably epitaxial interactions correlates with the carcinogenic activity of these substances. The presented results are in support of the assumption that a specific process of adsorption and crystallization with cholesterol of the plasma membrane takes place during the initial phase of the carcinogenesis by aromatic compounds.

Amines↗
PubMed2006

Structure-activity relationships for cytotoxic ruthenium(II) arene complexes containing N,N-, N,O-, and O,O-chelating ligands.

We report structure-activity relationships for organometallic RuII complexes of the type [(eta6-arene)Ru(XY)Cl]Z, where XY is an N,N- (diamine), N,O- (e.g., amino acidate), or O,O- (e.g., beta-diketonate) chelating ligand, the arene ranges from benzene derivatives to fused polycyclic hydrocarbons, and Z is usually PF6. The X-ray structures of 13 complexes are reported. All have the characteristic "piano-stool" geometry. The complexes most active toward A2780 human ovarian cancer cells contained XY=ethylenediamine (en) and extended polycyclic arenes. Complexes with polar substituents on the arene or XY=bipyridyl derivatives exhibited reduced activity. The activity of the O,O-chelated complexes depended strongly on the substituents and on the arene. For arene=p-cymene, XY=amino acidate complexes were inactive. Complexes were not cross-resistant with cisplatin, and cross-resistance to Adriamycin was circumvented by replacing XY=en with 1,2-phenylenediamine. Some complexes were also active against colon, pancreatic, and lung cancer cells.

2,2'-Dipyridyl↗
PubMedDate not supplied

Ubiquitous occurrence of 2-nitrofluoranthene and 2-nitropyrene in air.

Several nitrated polycyclic aromatic hydrocarbons (nitro-PAH) are direct-acting mutagens and/or carcinogens, and are important constituents of combustion emissions and ambient air. These nitro-PAH are emitted from various combustion sources including gasoline and diesel engine exhaust, aluminium smelting effluent, coal fly ash, wood smoke, and cigarette smoke condensates. Of these, diesel engine exhaust is the best characterized, more than 50 nitrated polycyclic aromatic compounds having been identified by Paputa-Peck et al., including 1-nitropyrene (1-NP) as the single most abundant nitro-PAH. However, nitro-PAH may also be formed during source-receptor transport by atmospheric reactions of adsorbed or gas-phase PAH with oxides of nitrogen, nitric acid and other atmospherically important species such as the OH radical. Evidence for the atmospheric formation of nitro-PAH has come only recently, from observations that 2-nitropyrene (2-NP) and 2-nitrofluoranthene (2-NF) neither of which has been reported to be emitted from combustion sources, are among the major nitro-PAH present in ambient air. We present here data from several locations which demonstrate that these two atmospherically formed nitro-PAH are ubiquitous in tropospheric ambient air.

Air Pollutants↗
PubMed1990

Mutagenicity of adsorbates to a copper-phthalocyanine derivative recovered from municipal river water.

Blue cotton, bearing a covalently bound copper-phthalocyanine derivative capable of adsorbing polycyclic aromatic hydrocarbons (PAHs) over 3 rings, was applied to recover mutagens from the Katsura River which is a tributary of the Yodo River. The Ames Salmonella/microsome assay with TA98 and TA100 of the blue cotton concentrate recovered from the river water demonstrated indirect mutagenicity toward TA98. The subfractions separated by Sephadex G-25 gel chromatography also showed direct mutagenicity in strains YG1021 and YG1024, the nitroreductase- and O-acetyltransferase-overproducing derivatives of TA98; this activity was greatly increased by the addition of S9 mix, especially in YG1024. However, these subfractions were less mutagenic with TA98NR or TA98/1,8-DNP6, regardless of whether S9 mix was present or not. The behaviors of these mutagenic activities therefore suggested that frameshift mutagens of both directly mutagenic nitroarenes and indirectly mutagenic aminoarenes were present in the blue cotton concentrate from the river water.

Adsorption↗
PubMed2002

Lack of genotoxicity of bitumen fumes in transgenic mouse lung.

During hot application of bitumen containing materials, e.g. in hot paving or roofing, fumes are emitted that contain polycyclic aromatic compounds. Previous studies with rodents exposed to bitumen and coal-tar fume condensates showed formation of DNA adducts. In order to clarify the genotoxicity of bitumen fumes, we designed a study by using mice carrying a reporter gene for mutagenesis analysis and exposed by nose-only to a constant and reproducible aerosol of bitumen fumes. We analyzed the genotoxic activity of inhaled bitumen fumes generated under those controlled conditions through the induction of mutation and DNA adducts in Big Blue mice. Mice were exposed to bitumen fumes (100 mg/m(3) total particulate matter) 6 h per day during 5 days by nose-only in an inhalation chamber designed in our laboratory. Following a 30-day fixation period, the experiment was terminated and lung DNA was extracted for mutant frequency and adduct determinations. The mutant frequency was determined using the cII and the lacI mutant analysis systems. In, addition, 61 and 54 mutants were sequenced in control and exposed groups, respectively. The study did not show any mutation or adduct induction in the exposed group compared to the control group: cII mutant frequencies were 11.0+/-4.5x10(-5) and 11.0+/-4.8x10(-5) in control and exposed lungs, respectively. Identically, using the lacI mutation detection system, the mutant frequencies were 6.4+/-3.1x10(-5) and 5.8+/-2.0x10(-5). The mutation spectra of both series were quite similar with regard to transition and transversion frequencies. The absence of genotoxicity in the group exposed to 100 mg/m(3) bitumen is discussed with regard to dosage of inhaled polycyclic aromatic compounds and species.

Aerosols↗
PubMed1977

[The phototoxic activity of carcinogenic polycyclic hydrocarbons and their degradation products in the biological test (author's transl)].

The phototoxic activity of carcinogenic polycyclic hydrocarbons was evaluated using ciliates of the species Tetrahymena pyriformis maintained in sterile, semisynthetic media. This ciliate-light-test was developed into and standardized for a rapid microbiological assay of carcinogenic activity of polycyclic aromatic hydrocarbons. --In this fashion, six polycyclic aromatic compounds with differing carcinogenic activities were tested:benzo(a)-pyrene, benzo(b)fluoranthene, indeno(1,2,3-c,d)pyrene, benzo(a)anthracene, fluoranthene, and cyclopenteno (c,d)pyrene. An essential parallelism between phototoxic and carcinogenic activities, resp., was clearly obvious. --The combined effects of benzo(a)pyrene and fluoride ions was also investigated using the ciliate-light-test. Fluoride ions in the concentration of 1 ppm did not affect the phototoxicity of benzo(a)pyrene, suggesting that fluorides possess no cocarcinogenic activities. --Degradation products of benzo(a)pyrene obtained by UV-irradiation (mixtures of quinones) were also tested for phototoxic activity. It could be shown that such degradation products entirely free from benzo(a)pyrene still possessed 50% of the activity of the original, non-irradiated solution. This is taken to indicate that the degradation products products resulting of UV-irradiation may still retain a measure of carcinogenic activity, --a finding of considerable importance from the viewpoint of environmental hygiene.

Animals↗