Yoshio Takase

CHANGES IN ENZYME ACTIVITIES IN SKIN FIBROBLASTS DERIVED FROM PERSONS OF VARIOUS AGES

We examined antioxidant enzyme activities (catalase, glutathione peroxidase, and superoxide dismutase) in cultured skin fibroblasts (passage number 2-3) derived from 30 persons of various ages. With increasing ages, catalase activity decreased, glutathione peroxidase activity increased slightly, and superoxide dismutase activity was unchanged. After UVA irradiation (4.8 joule/cm2) of the fibroblasts, only catalase activity decreased by 70%. This suggests that catalase may play an important role in the aging of human skin fibroblasts.

Studies on contact hypersensitivity in the guinea pig The cumulative contact enhancement test

A method to determine the quantitative induction and challenge of the allergenicity of externally applied toiletories and cosmetics, including their components, is described.

Tissue Culture Study of Dermatofibrosarcoma Protuberans

We cultured non‐epithelial cells derived from dermatofibrosarcoma protuberans (DFSP). The cells proliferated well, to the same degree as fibroblasts. DFSP cells, however, differed from fibroblasts in several aspects: 1) DFSP cells were bigger than fibroblasts, and grew in various directions, 2) acid phosphatase, and non‐specific esterase stained abundantly demonstrated in DFSP cells, 3) DFSP cells showed immunophagocytosis of Candida albicans and Staphylococcus aureus, and 4) DFSP cells had Fc and C3 receptors. DFSP cells are, therefore, considered to originate from histiocytes.

Low Glucose-6-Phosphate Dehydrogenase Activity in Cultured Skin Fibroblasts from Werner's Syndrome

Fibroblasts from leg skin of a patient with Werners syndrome were cultured. Their growth rate was lower than that of the normal control. They were variable in size and did not reach confluence. The activity of glucose‐6‐phosphate dehydrogenase (G6PDH) in this cell line was one seventh that of the normal control. The results of pulse labeling and chase experiments indicated that the rate of synthesis of G6PDH in the line was low, in agreement with the decrease in enzyme quantity.

Establishment of a Human Dermatofibrosarcoma Protuberans Cell Line: Cytological Characteristics

We established a dermatofibrosarcoma protuberans (DFSP) cell line derived from a DFSP tumor from a 69‐year‐old female. The population doubling time of the cells was about 45 hours. The cells were mostly round, although a few triangular or spindle‐shaped cells were also found. They could not be transplanted into nude mice.