Analysis of DNA single-strand breaks in human venous blood: a technique which does not require isolation of white blood cells.

For DNA strand break analysis in human white blood cells, usually metrizoate-Ficoll centrifugation is used to isolate mononuclear cells. This procedure is time-consuming and requires at least 20 ml of blood per sample. Therefore, we developed a technique which does not require isolation of white blood cells prior to DNA strand break analysis by alkaline elution (direct method). The sensitivity of this new technique was compared to that of the standard method, which includes isolation of mononuclear blood cells. A statistically significant increase in sensitivity was observed using the direct method. After in vitro gamma-irradiation of venous blood, an increase in the elusion rate of 7.7 × 1…

A multiplex polymerase chain reaction protocol for the simultaneous analysis of the glutathione S-transferase GSTM1 and GSTT1 polymorphisms.

Enhancement of the Mutagenicity of Ethylene Oxide and Several Directly Acting Mutagens by Human Erythrocytes and its Reduction by Xenobiotic Interaction

According to the present state of knowledge mutagenicity or genotoxicity of the ulti mate genotoxic agents ethylene oxide or styrene oxide cannot be increased by further me tabolism. However, in the present study we demonstrate that mutagenicity of several ultimate genotoxic substances is increased by human erythrocytes. For instance mu tagenicity of mafosfamide, N-nitroso-N-methylurea, ethylene oxide, and styrene oxide to Salmonella typhimurium TA 1535 was increased 5.5-, 5.1-, 2.7-, and 2.3-fold, respectively, by addition of human erythrocyte homogenate to the preincubation mixture in the Ames test. On the other hand, the mutagenicity of cumene hydroperoxide, benzo[a]pyrene-4,5-oxide, and…

Characterization of highly polar bis-dihydrodiol epoxide--DNA adducts formed after metabolic activation of dibenz[a,h]anthracene.

Dibenz[a,h]anthracene as well as a biologically important metabolite of dibenz[a,h]anthracene, namely the M-region dihydrodiol trans-3,4-dihydroxy-3,4-dihydrodibenz[a,h]anthracene were in addition to further metabolism to a bay region diol epoxide, extensively transformed to a distal bisdihydrodiol, 3,4,10,11-tetrahydroxy-3,4,10,11-tetrahydro-dibenz[a,h]anthracene, which exhibited after renewed metabolic activation high DNA binding efficiency, leading to a new class of very polar DNA adducts. After incubation of dibenz[a,h]anthracene with DNA in the presence of liver microsomes from Aroclor 1254 treated male Sprague-Dawley rats highly polar DNA adducts probably originating from 3R,4R,10R,11…