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Numerical taxonomy of Nocardia 总被引:7,自引:0,他引:7
46.
Schmitt H 《FEBS letters》1969,4(3):234-238
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C. A. Schreiner D. A. Edwards R. H. McKee M. Swanson Z. A. Wong S. Schmitt P. Beatty 《Cell biology and toxicology》1989,5(2):169-188
Catalytic reforming is a refining process that converts naphthenes to aromatics by dehydrogenation to make higher octane gasoline blending components. A portion of this wide boiling range hydrocarbon stream can be separated by distillation and used for other purposes. One such application is a mixture of predominantly 9-carbon aromatic molecules (C9 aromatics, primarily isomers of ethyltoluene and trimethylbenzene), which is removed and used as a solvent — high-flash aromatic naphtha. A program was initiated to assess the toxicological properties of high-flash aromatic naphtha since there may be human exposure through inhalation or external body contact. The current study was conducted partly to assess the potential for mutagenic activity and also to assist in an assessment of carcinogenic potential. The specific tests utilized included the Salmonella/mammalian microsome mutagenicity assay, the hypoxanthine-guanine phosphoribosyl transferase (HGPRT) forward mutation assay in CHO cells, in vitro chromosome aberration and sister chromatid exchange (SCE) assays in CHO cells, and an in vivo chromosome aberration assay in rat bone marrow.There was no evidence that high-flash aromatic naphtha was either a gene or chromosomal mutagen. Thus it is unlikely to be a genotoxic carcinogen.Abbreviations Brdu
5-Bromo-2-deoxyuridine
- C9
Aromatic species with 9 carbons (i.e., ethyl toluene and trimethyl benzene isomers)
- CE
Cloning efficiency
- CHO
Chinese hamster embryo
- CP
Cyclophosphamide
- DMSO
Dimethyl sulfoxide
- HGPRT
Hypoxanthine-guanine phosphoribosyl transferase
- HVAC
Heating, Ventilation, Air Conditioning
- 3MC
3 Methylcholanthrene
- MMC
Mitomycin C
- MMS
Methyl methanesulfonate
- S9
S9 Mammalian microsomal enzyme activation mixture
- SCE
Sister chromatid exchange 相似文献
49.
D Schmitt C Dezutter-Dambuyant D Hanau D A Schmitt H V Kolbe M P Kieny J P Cazenave J Thivolet 《Comptes rendus de l'Académie des sciences. Série III, Sciences de la vie》1989,308(10):269-275
Langerhans cells (LC) are epidermal dendritic cells which express several surface antigens among them the CD4 antigens. We investigated the fate of HIV envelope glycoproteins (gp 120 and gp 160) incubated with healthy human trypsinized LC in suspension. After trypsin treatment only the epitope for OKT4 appeared to be resistant. In absence of antigenic sites identified by OKT4A, Leu 3a or BL4, LC fixed and internalized gp 120 or gp 160 recombinant HIV proteins. This finding support the hypothesis that there exists at the surface of LC a second molecule which may act as a HIV receptor. 相似文献
50.
Glucocorticoid and thyroid hormones inhibit proliferation of serum-free mouse embryo (SFME) cells 总被引:3,自引:0,他引:3
Mouse embryo cells derived in a serum-free medium formulation (SFME cells) do not exhibit growth crisis or chromosomal abnormalities and are nontumorigenic in vivo; these cells are also reversibly growth inhibited by serum or platelet-free plasma (Loo et al.; Science, 236:200-202, 1987). A portion of the inhibitory activity of serum could be extracted by charcoal, a procedure that removes steroid and thyroid hormones. Both L-3,5,3'-triiodothyronine (T3) and hydrocortisone inhibited growth of SFME cells in a reversible manner. The inhibitory activity of serum also was partially removed by treatment with anion exchange resin in a procedure designed to deplete serum of thyroid hormone. However, the effect of serum on untransformed SFME cells could not be prevented by addition of the antiglucocorticoid RU38486, and ras-transformed clones of SFME cells, which are capable of growing in serum-containing medium, retained inhibitory responses to glucocorticoid and, with some clonal variability, to T3. These results suggest that glucocorticoid or thyroid hormones may contribute to the inhibitory activity of serum on SFME cells, but additional factors are also involved. 相似文献