In two previous studies (Steiner14,15) 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.
STEINER K. Fluorescence Microscopy of Normal and Pathologic Keratin. Arch Dermatol. 1960;82(3):352–361. doi:10.1001/archderm.1960.01580030046006
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