Those originally employed were based either on the fusion of the PCE to a tumour specific antibody (Antibody-Directed Prodrug Therapy, ADEPT) or on the delivery of the gene encoding the PCE using viral or non-viral vectors (Gene-Directed Enzyme Prodrug Therapy, GDEPT).
Urea is widely used in fertilizers as a source of nitrogen and is an important raw material for the chemical industry. Friedrich WÃ¶hler's discovery in 1828 that urea can be produced from inorganic starting materials was an important conceptual milestone in chemistry.
Dr. Cheny did quite a few studies (here, here and here are just a few of the studies he published) that indicated the efficacy of using fresh raw cabbage juice to treat ulcers of many kinds. As a result, Vitamin U (unidentified substance) became part of the naturopathic arsenal.