TABLE OF CONTENTS The effect of corrosion is that metallic ions are released into the body, and this may lead to local inflammatory response, or to more profound reactions, i.e. either mutagenesis or carcinogenesis. Although there is a link between these latter two biological effects, they are not synonymous, though most mutagens are carcinogens and vice versa.15
A mutagenic agent is one that brings about mutations, i.e. which causes the loss or appearance of a characteristic that can be inherited by subsequent generations. This requires that the agent interacts with the DNA of the organism and causes some sort of primary lesion in that DNA. Often, when such lesions occur, they can be repaired by the repair enzymes of the cell, but if there is some deficiency or overload of these enzymes, the lesion will persist. When the cells divide, this error will be replicated, and result in transformation into a mutation. The numbers of such lesions need to be small, or the cell will die, either because its vital functions are impaired, or because it will experience so-called apoptosis, or programmed cell death. On the other hand, cells with only small numbers of such lesions may be viable. They are therefore able to survive, replicate, and pass on the error on their DNA.
Mutations may affect either genes or chromosomes. Gene mutations are essentially of two types:
Base pair substitutions. In this type of mutation, one base pair is replaced by another base...
