AN ULTRASTRUCTURAL STUDY OF NUCLEOLAR ENLARGEMENT FOLLOWING ULTRAVIOLET IRRADIATION OF HUMAN EPIDERMIS

[摘要] Biopsy specimens of normal human epidermis irradiated with ultraviolet light were studied by electron microscopy. A marked increase in size of nucleoli in the spinous layer of the epidermis in the 72 hr. post-irradiation specimens was observed. Statistical analysis of the size of the 72 hr. irradiated and control nucleoli showed this increase to be significant. Nucleolar enlargement correlated with stratum corneum thickening suggests that nucleolar enlargement is associated with increased protein synthesis by the epidermis.