The toxic and osteolathyrogenic effects of 15 chemicals reflecting modifications of semicarbazide [H2N-N(H)-C(=O)-NH2] were evaluated using the Frog Embryo Teratogenesis Assay: Xenopus (FETAX). Osteolathyrism, the failure of connective tissue fibers to cross-link correctly, is expressed as gross alterations in the long axis of the embryo and a sinusoidal configuration of the notochord. Alteration (addition or subtraction) at the hydrazino (H2NNH-) end of the molecule sharply reduces osteolathyrogenic activity. Alteration at the amino (H2N-) end of the molecule results in a graded response. The replacement of oxygen with sulfur causes no loss of osteolathyrogenic activity.
Available at: http://works.bepress.com/terry_schultz/176/