Production of ring-shaped particles by normal and metaplastic tissue. I. Human skin.

: Maintenance media incubated with biopsy specimens of human skin tissues contained minute (10-12 nm wide), ring-shaped particles (RSP) similar to those described previously in culture media of mammalian cell lines. In addition to the qualitative demonstration of the particles by electron microscopy, a quantitative method was applied to estimate in media the amount of DNA that could be attributed primarily to RSP content. The amounts of DNA, obtained with 146 test specimens, varied with the pathologic condition of the tissue in the following ascending order: normal skin, verruca vulgaris, seborrheic verruca, actinic keratosis, basal cell carcinoma, and squamous cell carcinoma.