MUTAGENS OF POTENTIAL SIGNIFICANCE 235 



difiSculty inherent in such a system: human cells are diploid and there- 

 fore one cannot detect recessive mutations. He suggested that either 

 a search be made for haploid tissue, if any such thing exists, or some 

 special tricks, such as using only males and sex-linked mutations. 



Dr. Goldstein pointed out that it would be of practical value, even 

 right now, if we had several drugs which have about the same effect. 

 We should avoid those drugs in this list which have been shown to be 

 mutagens because, if we can avoid them without sacrificing the 

 therapeutic value, why not do it? 



He then mentioned that what worries him in particular is that 

 although caffeine may be a weak mutagen, perhaps there are some 

 other potential dangerous drugs or chemicals which are still undis- 

 covered, and perhaps we should search for those. He has given a list 

 of such chemicals which are used by large portions of the population 

 for a long time; the list includes ethyl alcohol, which a priori looks 

 innocent but is not so innocent when we realize that it is changed in 

 the normal metabolic process into acetaldehyde, which is not very 

 unlike the mutagen formaldehyde. Nicotine has been shown to produce 

 chromosome abnormalities in plants. There is a large group of chem- 

 icals which are in constant use, such as additives to water supplies 

 and foods, insecticides, etc. Their mutagenicity has not been proved, 

 but as he mentioned before, there too, some mutagenic agent could be 

 lurking in the dark. 



He also mentioned vitamins, and there I reported in a few words 

 the mutagenicity of ascorbic acid. Although ascorbic acid by itself may 

 not be very interesting as a mutagen, the fact that some, if not all cells, 

 cannot live without ascorbic acid makes it important to study this vita- 

 min and the whole class of natural mutagens which are present in 

 normal cells. I gave an example of Novick and Szilard's pioneer research 

 in which they found adenine to be mutagenic. 



Going into details on caffeine, Dr. Goldstein first mentioned that 

 this purine does not act by being incorporated in DNA, because that has 

 never been reported. He has quoted statistics of the use of caffeine, 

 exposures of gonads to caffeine, and he actually made measurements 

 of distribution and proved that caffeine is accumulated there. Al- 

 though the caffeine is eventually metabolized, the biological half life 

 being around 3.5 hours, this period is long enough for caffeine to exert 

 an effect; in addition, we cannot even prove that the products of 

 normal metabolism of caffeine are harmless. 



There was a question as to whether caffeine, which can actually 

 reach the gonads — and he quoted experiments which seem to prove 

 that it did — can pass through maternal blood to fetal blood. 



