Anti-mesodermal Activity of a Nitrogen Mustard Derivative

Amongst the numerous derivatives of nitrogen mustard that have been tested for their anti-tumour activity on Walker carcinoma by Danielli and his collaborators (1961), (Cl—CH2—CH2)2: N—C6H4—O—CO—NH—C6H4—COOH, i.e., p-(NN-Di-2-chloroethyloamino)-phenyl- N-(p-carboxyphenyl) - carbamate (later referred to as I.C. 140), has been found to be particularly promising. To check its cytotoxic activity for embryos, and to find out, if possible, whether I.C. 140 has any specific selectivity for particular embryonic tissues, chick and mouse embryos were treated during the early stages of development. Chick embryos were explanted according to the method described by New (1955) at Stage 4 or 5 (Hamburger & Hamilton, 1955), i.e., after a pre-incubation period of 22 hr. As I.C. 140 is difficult to dissolve in water, it was first suspended in an appropriate volume of 0·9 per cent, saline solution. One part of this suspension was then diluted with nine parts of liquid albumen to give the final concentration of 50 or 100 μg. per ml.