Further in vitro studies on the biochemistry of the inhibition of nucleic acid and protein synthesis induced by arsenic.

Human lymphocytes, stimulated by PHA, and exposed to increasing Na2HAsO4 concentrations, show an identical incorporation rate for 14C thymidine and 14C-TTP into the DNA. 14C uridine is incorporated 3--4 per cent less at an As concentration of 1.0 mug/ml medium, above this however approximately 15 per cent less into the RNA as compared to 14C-UTP.

[The effect of fumaric acid monoethylester on the synthesis of nucleic acids and proteins of PHA-stimulated human lymphocytes (author's transl)].

Fumaric acid monoethylester (FAME) inhibits the incorporation of 14C-Thymidin, 14C-Uridin, 14C-Alanin and 14C-Leucin into acid-insoluble biopolymers of cultivated PHA-stimulated human lymphocytes. At high concentrations of FAME (500 mug/ml culture medium) the inhibition of nucleic acid synthesis is 6 times higher on the average than the inhibition of protein synthesis. However, the application of the cis-isomer, maleic acid monoethylester (MAME), results in an increase of the incorporation rate of the labelled precursors into the RNA and DNA.