[Changes in the ultrastructure of human epidermis as a result of freezing].

Freezing at -35 degrees C and -70 degrees C of unfixed human epidermis brings about an electron microscopic increase of intercellular spaces, a destruction of cellular membranes, homogenization of tonofibrils, and a decrease in the volume of mitochondria with a partial destruction of their inner surface. Nuclear changes are characterized by disruption of nuclear membranes and by massive passage of nucleoproteids into the cytoplasm. Destruction and fragmentation of cytolemma and nuclear membranes is accompanied by formation of myelin-like figures. Freezing at -70 degrees C leads to greater changes in the structure of the epidermis cells, and is accompanied by the appearance of vacuoles of different sizes and shape in the horny scales and in the cytoplasm of some epidermal cells. This is probably due to formation of ice crystals.