ABSTRACT
The discovery of superoxide dismutase provided a highly specific probe for the implication of the superoxide free radical in numerous biological processes. From the beginning, though, there were those who were disquieted by the rather robust nature of the damage which was apparently inflicted by this relatively mild-mannered radical. From a physiological or clinical perspective, the important point to appreciate is that iron may seriously exacerbate any oxidative stress. It is this iron, liberated by the pathological production of superoxide that is now free to catalyze Haber-Weiss chemistry and to wreak additional cellular havoc. The human condition known as Down's syndrome, or trisomy 21, has provided some provocative clues regarding the concept of balance between oxidants and antioxidants. The development of animal and cultured cell models which allow examination of specific gene-dosage effects has shed new light on the subject. With the advent of molecular biology, it has become possible to manipulate levels of gene expression.
