[Rat liver mitochondrial DNA treated with 1,2-dimethylhydrazine].

Primary structure of 5'-end 16S RNA gene of mitochondrial DNA (mDNA) isolated from rat liver tissue within 20 hrs after treatment with 1,2-dimethyl hydrazine, was analyzed. The preparations studied did not contain mutations induced by the drug. The region of mDNA analyzed appears not to be a preferential target for mutagenic effect of 1,2-dimethyl hydrazine unber these experimental conditions.

[The testing for carcinogenicity of a polyethylene terephthalate vascular prosthesis].

A long-term for possible carcinogenicity was conducted by subcutaneous implantation of 1 cm 2 pieces of polyethylenetherophthalate vascular grafts (PET-VG) to 150 BDF1 mice and 120 Syrian golden hamsters of either sex. A false operation was carried out in the same number of animals of control groups. Implantation was performed in nine-week-old animals.

[Comutagenic action of sodium selenite and caffeine on S. typhimurium TA 1535 with its subsequent treatment by N-nitrosomethylurea].

The comutagenic activity of sodium selenite and caffeine was studied by the Ames test. Reproduction of S. typhimurium TA1535 for 4 h at 37 degrees C in the nutrient broth with sodium selenide (5 micrograms/ml) significantly increased sensitivity of bacterial cells to the mutagenic action of 2-3 mM N-nitrosomethylurea (NMU).

[Antiradical activity and sulfhydryl group concentration in normal and tumor tissue].

In cytosol of normal and tumor tissues obtained from rats and hamsters, antiradical activity (ARA) of bioantioxidants was assayed by the method of Glavind, while the content of sulfhydryl groups by the method of Ellman. ARA of normal tissues (liver, kidneys, stomach, large intestine, femoral muscles) was lower than the content of free SH-groups. The difference between the magnitudes under consideration was always negative in all the test tissues.