X-ray microanalysis in dermatology.

The current trends in X-ray microanalysis as applied to dermatology are described by reviewing papers which have made a significant contribution to the field. Under separate headings, the analysis of hair, nail and epidermis is reviewed with an emphasis on quantitative results. Our recent work on green hair has revealed a higher than normal copper content derived from copper-containing tap and pool water. In nail the sulfur content was shown to be evenly distributed throughout the nail plate and the calcium content to be too low to influence on the "hardness" of the nail. Our study of nails from cystic fibrosis patients showed that the Na, K, and C1 content increased, which is diagnostic for the disease, and that the Ca content could be used to monitor the preparation of nail samples for analysis. With the aid of X-ray microanalysis it has been possible for the first time to study the electrolyte composition of the different strata of epidermis by using freeze-fixed and freeze-dried cryosections. Only the basal stratum maintains a normal Na/K quotient and all cell layers above that one appear to have dysfunctional cell membranes, i.e. inadequate pumping of Na out of the cells. A subsequent study of the effects on normal epidermis by DNCB showed that after 6 hours post-treatment, abnormal Na, K and P levels appeared which differed from those seen in post-mortem changes of normal epidermis.