No abstract

Wrinkles in six aged persons (67-82 years of age) have been investigated by light microscopy (LM) and scanning electron microscopy (SEM). There are two types of wrinkles. One is a deep wrinkle which develops on the sun-exposed skin and does not disappear on stretching (permanent wrinkle). The LM and SEM showed less elastotic change in the upper dermis in the area of wrinkle than in that of the surroundings. The other type is a shallow wrinkle which develops on sun-protected skin and disappears on stretching (temporary wrinkle). The LM and SEM showed the decrease or loss of the elastic fibres in the papillary dermis as seen in ageing skin.

We report a case of microcystic adnexal carcinoma (MAC) occurring on the upper lip of an 82-year-old woman. Microscopically the tumor showed both pilar and sweat gland differentiation, involved the entire dermis and subcutaneous tissue, and invaded perineural spaces. Immunoperoxidase studies revealed carcinoembryonic antigen to be present in the ductal lining cells and in the amorphous content in the lumen, confirming sweat gland differentiation. The S-100 protein was positive in dendritic cells within the solid cell nests, but negative in cells lining cystic spaces. Ultrastructural study confirmed that the neoplasm was composed of two components, with pilar and eccrine differentiation. The former showed concentric layers of squamous epithelial cells with well-developed desmosomes and cytofilaments. The latter had ductal and alveolar structures; the ultrastructural features included: i) numerous villous folds of plasma membrane to interdigitate each other by focal desmosomes, ii) aggregates of cytofilaments, and iii) basally located myoepithelial cells which were separated from the surrounding stroma by rather thick basement membrane. In addition, distinct amyloid deposition was also observed on ultrastructural examination. To our knowledge, amyloid deposition has not been previously reported in MAC.

Age-related changes in human dermal elastic fibres were studied by scanning (SEM) and transmission (TEM) electron microscopy. The SEM findings showed an increase in the complexity of shape and arrangement of the fibres including flattening and branching, an increase in the roughness of the surface, and a decrease in interfibrillar areas. The TEM findings showed a decrease in micro-fibrils and amorphous material, and an increase in electron dense inclusions followed by the appearance of vesicular structure.

The proliferation and cell cycle phase composition of human dermal fibroblasts cultured on or in type I collagen lattices (reconstituted dermis model) were examined. On collagen lattices, as compared with conventional cultures on plastic dishes, the proliferation of human dermal fibroblasts was suppressed, being arrested at about one-half the saturation density after 10 days of culture. In collagen lattices, proliferation was further suppressed, being nearly arrested within 4-7 days of culture. Cells were analyzed for cell cycle phases by two-color flow cytometry using DNA staining and S phase cell staining with FITC-conjugated antibromodeoxyuridine antibody. After 5 days of culture, the number of S phase cells on collagen lattices was 49.3% of that on plastic dishes, with an increase in G0G1 phase cells of 79.8%. In collagen lattices, the number of S phase cells was very small (4.3% of all cells), and most of the cells accumulated in G0G1 phase. These findings suggest that the cell cycle of fibroblasts is arrested at G0G1 phase by their interaction with collagen. On the basis of these results, the reconstituted dermis model using collagen lattice is considered to be analogous to the dermis in vivo with respect to cell growth and cell cycle phase composition.