Kenneth G. Jensen

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The kinetics of phenacetin O-deethylation and its inhibition by fluvoxamine was investigated in a V79 cell line (V79MZh1A2) transfected with human CYP1A2. In four sets of experiments the apparent Km values for phenacetin O-deethylation ranged from 35 to 95 microM and the Ki for fluvoxamine-mediated inhibition of the reaction ranged from 2.7 to 14.5 nM, i.e.(More)
Di- and tri-methyl, -butyl and phenyl tin, all as chlorides were tested for toxicity and spindle disturbances in V79 Chinese hamster cells and for effects on in vitro assembly of bovine brain tubulin. The V79 cells were treated for 30 min and in general, loss of a stainable spindle could be demonstrated at slightly higher concentrations than c-mitosis. Both(More)
Although aneuploidy makes a significant contribution to both somatic and inherited disease the mechanisms by which environmental chemicals may induce numerical chromosome aberrations are only poorly defined. The European Union Project was aimed to further our understanding of those chemical interactions with the components of the mitotic and meiotic cell(More)
In vitro exposure of PHA-stimulated human lymphocytes to organotin compounds resulted in statistically significant increases in the frequencies of hyperdiploid cells. When taken together with our previous study demonstrating spindle inhibiting effects of the same organotin compounds by an indirect method (Jensen et al., 1989), the present study strongly(More)
Spindle disturbing effects in terms of c-mitosis and cytotoxicity of paracetamol were investigated in two Chinese hamster V79 cell lines, one of which (V79MZh1A2) was transfected with human CYP1A2. This enzyme catalyses the oxidative formation of the reactive paracetamol metabolite, NAPQI, believed to initiate hepatoxicity by covalent binding to proteins(More)
Recently we showed that ascorbate and 5-aminosalicylic acid (5-ASA) prevented 8-hydroxydeoxyguanosine (8-OHdG) formation in calf thymus DNA exposed to UV-visible light. However, the ultimate defense against oxidative DNA damage depends on an intracellular/intranuclear effect of the compounds. In the present study we investigated the effect of ascorbate and(More)
A group of chlorophyll deficient mutants (br s mutants) of Chlamydomonas accumulates protoporphyrin and has poorly developed chloroplast membrane systems (Wang et al. 1974). In order to determine whether a poorly developed chloroplast membrane system is the reason for, or the result of, the inability of the br s mutants to metabolize protoporphyrin to(More)
In a genetically engineered V79 cell line (XEMd-MZ) expressing rat cytochrome P4501A2 the activity of phenacetin-O-deethylase was determined and compared with freshly isolated rat hepatocytes. In the V79 cells the apparent Km was 0.99 microM (N = 4), compared to the high affinity Km (0.23 microM, N = 4) found in freshly isolated rat hepatocytes, where as(More)
The polychlorinated biphenyls 2,2',5,5'- and 3,3',4, 4'-tetrachlorobiphenyl, 2,3,3',4,4'- and 3,3',4,4', 5-pentachlorobiphenyl and 2,2',4,4',5,5'-hexachlorobiphenyl were tested for spindle-disturbing activity in V79 Chinese hamster cells. Clones lacking endogenous cytochrome P450 activity or expressing rat CYP1A1 or CYP2B1 were used. Induction of abnormal(More)