Fluorescence Microscopy of Normal and Pathologic Keratin

Abstract

In two previous studies (Steiner^14,15) it was noticed that in parakeratoses and hyperkeratoses the stratum corneum seems to contain ribonucleic acid (RNA). This observation was made on sections pretreated with ribonuclease (RNase) before staining with methylgreen-pyronin. It was felt, however, that the quantitative differences between RNase-treated and untreated sections were not significant enough to permit a definite conclusion as to the presence of RNA in the stratum corneum. In order to unequivocally demonstrate RNA it appeared desirable to employ a different histochemical method. In studying hair keratin Jarrett¹¹ showed that RNase abolished the brilliant fluoresscence of thioflavine-stained inner root sheaths. Since such a qualitative change of fluorescence reveals the presence of RNA with certainty, it was decided to apply the fluorescence method to epidermal tissues. In the following, the results of a fluorescence study in regard to the normal and pathologic epidermis and stratum corneum are being described.