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PubMed1991

Reduction of nitroaromatic compounds by anaerobic bacteria isolated from the human gastrointestinal tract.

Human intestinal microbial flora were screened for their abilities to reduce nitroaromatic compounds by growing them on brain heart infusion agar plates containing 1-nitropyrene. Bacteria metabolizing 1-nitropyrene, detected by the appearance of clear zones around the colonies, were identified as Clostridium leptum, Clostridium paraputrificum, Clostridium clostridiiforme, another Clostridium sp., and a Eubacterium sp. These bacteria produced aromatic amines from nitroaromatic compounds, as shown by thin-layer chromatography, high-pressure liquid chromatography, and biochemical tests. Incubation of three of these bacteria with 1-nitropyrene, 1,3-dinitropyrene, and 1,6-dinitropyrene inactivated the direct-acting mutagenicity associated with these compounds. Menadione and o-iodosobenzoic acid inhibited nitroreductase activity in all of the isolates, indicating the involvement of sulfhydryl groups in the active site of the enzyme. The optimum pH for nitroreductase activity was 8.0. Only the Clostridium sp. required added flavin adenine dinucleotide for nitroreductase activity. The nitroreductases were constitutive and extracellular. An activity stain for the detection of nitroreductase on anaerobic native polyacrylamide gels was developed. This activity stain revealed only one isozyme in each bacterium but showed that the nitroreductases from different bacteria had distinct electrophoretic mobilities.

Chromatography, High Pressure Liquid↗
PubMed2006

Temporal trends and relationships of particulate chlorinated polycyclic aromatic hydrocarbons and their parent compounds in urban air.

Concentrations of 12 chlorinated polycyclic aromatic hydrocarbons (CIPAHs) and the corresponding 5 parent PAHs associated with particulates in urban air in Shizuoka, Japan, were investigated from 1992 to 2002. Among the seven target CIPAHs that were detected in the air samples, 6-chlorobenzo[a]pyrene (6-ClBaP) had the highest mean concentration (15 pg m(-3)), followed by 1-chloropyrene (5.2 pg m(-3)) and 7-chlorobenz[a]anthracene (3.1 pg m(-3)). The concentrations of all the ClPAHs and PAHs, except 6-ClBaP, were higher in winter than in summer. Over the study period, the concentrations of the CIPAHs, except 6-ClBaP, remained almost constant, whereas the parent PAH concentrations declined moderately. There was significant correlation between the concentrations of the ClPAHs (except 3,9- and 9,10-dichlorophenanthrene) and the concentrations of the corresponding parent PAHs. Compositional analysis showed that the proportions of the detected PAHs generally did not vary over the period, whereas the proportion of 6-ClBaP relative to the total ClPAH concentration decreased over time. Comparison of the concentration profile of certain ClPAHs normalized to the concentration of 3-chlorofluoranthene, which is relatively photostable, with the profile for a traffic air sample reported previously revealed that there was no similarity between the two profiles. Factor analysis indicated that the atmospheric behavior of the ClPAHs, except for 6-ClBaP, may be similar to that of the parent PAHs, and that the atmospheric behavior of 6-ClBaP may differ from that of the other ClPAHs. The factor analysis also suggested that the emission sources for the ClPAHs (except for 6-CIBaP) may be similar to the sources of the parent PAHs.

Air↗
PubMed1982

[Mutagenic effect of polycyclic aromatic hydrocarbons (PAH) and polar organic compounds (POC) in urban aerosols].

The concentrations of the polycyclic aromatic hydrocarbons (PAH) and the polar organic fraction (polar organic compounds = POC) as part of the aerosol particles, collected on fiberglass filters with a six-stage high volume cascade impactor from 17.7. to 9.10. 1981 from Berlin (West) air, were determined.--The two fractions were tested for their mutagenicity by using the Salmonella typhimurium bioassay (Ames-test). According to their site of deposition in the human respiratory system the aerosol particles were fractioned into two classes: "A" (Dae = 1.3-10.2 microns) and "B" (Dae = 0.4-1.3 microns). The following data were obtained: 1. The ether extractable organic matter (EEOM) contains 8.9-12.0% PAH and 40.1-65.8% POC. 2. PAH and POC extracted from particles with a Dae:1.3-10.2 microns exhibit nearly the same mutagenic activity after metabolic activation whereas the POC derived from particles with a Dae:0.4-1.3 microns (lung penetrating fraction) result in a higher mutagenicity than the PAH. 3. The POC show a higher mutagenic activity without metabolic activation than the PAH. 4. Generally extracts derived from particles with a Dae:0.4-1.3 microns exhibit higher mutagenic effects than those derived from particles with a Dae:1.3-10.2 microns.

Aerosols↗
PubMed1998

SFE plus C18 lipid cleanup method for selective extraction and GC/MS quantitation of polycyclic aromatic hydrocarbons in biological tissues.

Lipid material represents a potential interference for determination of nonpolar compounds (e.g., polycyclic aromatic hydrocarbons) in biological tissue samples. This study reports the development of a selective extraction method using supercritical CO2 that allows the GC/MS quantitation of PAHs in the presence of a substantial lipid background. Selective extraction of PAHs relies upon addition of C18 adsorbent beads to the initial sample slurry. The dried mixture, including C18 adsorbent, is placed in the supercritical fluid extraction (SFE) chamber. During the SFE process, lipids are preferentially retained on the C18 beads. This "SFE plus C18" procedure was developed by first optimizing SFE conditions (100 degrees C, 350 bar) for recovery of PAH standards. PAHs containing added model lipid compounds (stearic acid and cholesterol) were then subjected to SFE plus C18 treatment followed by GC/MS analysis. Using this approach, a recovery of 94-100% of PAHs was obtained while only 9-17% of the lipid material present was coextracted from the same test sample. The developed method is demonstrated to permit efficient recovery and detection of PAHs spiked into crab tissue, a matrix with a high lipid content.

Animals↗
PubMed1984

Biologic and biochemical effects of mitoxantrone.

Mitoxantrone (1,4-dihydroxy-5,8-bis[(2-[(2-hydroxyethyl)-amino]-ethyl) amino]-9,10-anthracenedione dihydrochloride) is a representative of a new class of chemical compounds with antineoplastic activity. It was one of a number of polycyclic aromatic compounds tested at the American Cyanamid Laboratories and was the most effective and potent derivative synthesized. Mitoxantrone produced significant increases in life span and long-term survivors when tested against P388 and L1210 leukemias, B16 melanoma, and colon tumor 26 transplanted into mice. In comparative animal trials, it proved more effective than most of the other agents tested, including doxorubicin, cyclophosphamide, methotrexate, cytarabine, and 5-fluorouracil. It was also active against intravenously implanted L1210 leukemia, in contrast to doxorubicin, though this is considered to have a similar mode of action. Mitoxantrone also demonstrated moderate activity against sublines of the mouse leukemias, which were resistant to anthracyclines. Significant therapeutic synergism against P388 leukemia was observed when mitoxantrone was administered on the same day as methotrexate and cytarabine or in sequence with cyclophosphamide, cisplatin, or vincristine sulfate. Mitoxantrone is active intraperitoneally, intramuscularly, subcutaneously, and intravenously, but oral activity has not been demonstrated. Although dose schedule did not appear critical, treatment every 4 days X 3 appeared to be the most effective. The mechanism of action of mitoxantrone has not been fully elucidated, but it is known to inhibit DNA and RNA synthesis. In cell culture, mitoxantrone induces nuclear aberrations with chromosomal scattering and morphologic alterations similar to those induced by doxorubicin. Drug-induced cell kill was not phase specific. Experiments with a resistant human colon carcinoma cell line (WiDr) indicated that resistance may be due to alterations of the cell membrane with decreased uptake. Mitoxantrone has markedly less cardiotoxicity than doxorubicin, and this may be linked to the fact that the drug does not induce free radical formation but inhibits lipid peroxidation.

Animals↗