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S Itami

Publications and source records attributed to S Itami.

104 records · Page 6Linked to original sources
PubMed1986

A cell-spreading inhibitor exists in serum and in epidermal basal cells.

A unique monoclonal antibody was obtained by immunizing mice with complement-inactivated fetal bovine serum (FBS). This antibody, named SI-1, stained epidermal basal cells of humans, pig, guinea pig, and rat by an indirect immunofluorescence technique after pretreatment of cryostat sections with alkali buffer (pH 9.6). After dissociating pig epidermal cells by trypsin, the SI-1 antibody stained exclusively and strongly one type of uniquely shaped cells. They were small and hanging-bell or columnar in shape with one convoluted side on the base, consisting of less than 2.8% of the dissociated epidermal cell population. The antigen contained in FBS was partially purified by affinity chromatography using the SI-1 antibody. The affinity-purified antigen inhibited the spreading of PAM cells, a spontaneously transformed murine keratinocyte line, in serum-free medium in a dose-dependent manner at concentrations of 10(-5) to 10 ng/ml. The antigen also inhibited the spreading of trypsinized pig epidermal cells in the range of 10(-2) to 10(3) ng/ml in the presence of 0.05% FBS. Although there have been a few reports indicating that serum inhibited both spreading and attachment, a specific factor in serum has not been purified before. This is, to our knowledge, the first presentation of a cell-spreading inhibitor contained in serum.

Animals↗
PubMed1986

Monoclonal antibodies against epidermal cell surface and dermal-epidermal junction: antigens which may be epidermal cell spreading factors.

Two monoclonal antibodies which reacted with the epidermal cell surface (SF-1) and the dermal-epidermal-junction (SF-2), respectively, were obtained by immunizing mice with partially-purified human epibolin. The corresponding antigens were partially purified from fetal bovine serum by affinity chromatography using these antibodies. SDS-polyacrylamide gel electrophoresis showed that these antigens contained polypeptide components with molecular weights different from that of epibolin (mol. wt. 65,000 daltons); SF-1 antigen had a 68,000 dalton main component, and SF-2 antigen a broad 58,000-61,000 dalton main component. Both of these partially-purified antigens promoted the spreading of dissociated pig epidermal cells. SF-2 antigen also promoted the spreading of Pam cells (a murine keratinocyte line). The results suggest that proteins capable of promoting epidermal cell spreading may be present on the epidermal cell surface and at the dermal-epidermal junction. However, their physiological role in keratinization remains to be elucidated.

Animals↗
PubMed1985

[Antiandrogens].

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Androgen Antagonists↗
PubMed1984

Calcium-activated, phospholipid-dependent protein kinase in pig epidermis.

We investigated calcium-activated, phospholipid-dependent protein kinase in pig epidermis. Pig epidermal homogenates were centrifuged at 30,000 g for 30 min, and the supernatant was applied on a DEAE-cellulose column for purification. The partially purified enzyme was stimulated by simultaneous addition of Ca2+ and phospholipid. Successive addition of small amounts of diolein further activated the enzyme activity. The calcium-activated phospholipid-dependent protein kinase preferentially phosphorylated serine residues and its endogenous substrate protein in the pig epidermis has a molecular weight of about 97,000.

Animals↗
PubMed1984

Serial transplantation to nude mice of an androgen-dependent pilosebaceous tumor developed in Suncus murinus.

The pilosebaceous tumor spontaneously developed on the sidegland of an old male Suncus murinus was serially transplanted into male nude athymic (BALB/c-nu/nu) mice. By the 18th generation, tumor growth occurred in about 70% of them. The transplantability of the tumor maintained in these male mice to female or castrated male nude mice was less than 35%. The histological features of the tumor did not differ by the hormonal status of hosts. Tumor growth started later and was slower in females than in males. This androgen dependency seems to be restricted to an initial period of growth, since the transplantability to males was decreased by castration within a week after grafting. The tumors grown in males possessed both cytoplasmic and nuclear androgen receptors and those in females cytoplasmic androgen receptor only. The latter tumors were found androgen-sensitive, because treatment with testosterone propionate significantly increased tumor size. In addition, after [3H]-testosterone administration, bound radioactivity was detected in the nuclear fraction from female as well as male hosts. Although the mechanism responsible for the development of these androgen-independent sensitive cells is unknown, the variance in transplantability to female hosts suggests that the original tumor was composed of androgen-dependent and androgen-independent cells.

Animals↗
PubMed1983

An androgen-dependent pilosebaceous tumor spontaneously developed in the Japanese house musk shrew Suncus murinus.

Following administration of [3H]testosterone to castrated male Japanese house musk shrews (Suncus murinus), radioactive metabolites were detected in sidegland nuclei and the major one of them was dihydrotestosterone (DHT). The androgen binding capacity of the cytoplasmic fraction of sideglands was measured in vitro by the use of [3H]R1881 as a ligand. The binding showed a high affinity for R1881 (Kd = 6.2 X 10(-10) M) and a low capacity (Bmax = 22 fmol/mg protein). Sucrose density gradient centrifugation brought about a peak of [3H]R1881 in the 7S region in low ionic strength buffer. Their characteristics as described above are consistent with those of other androgen target organs. A cutaneous pilosebaceous tumor, which spontaneously developed on the sidegland of old male S. murinus, was transplanted to nude athymic mice. It grew in males only and failed to grow in females and castrated males. A specific androgen binding was found in this tumor (Kd = 7.8 X 10(-10) M, Bmax = 100 fmol/mg protein). Therefore, this transplantable pilosebaceous tumor is androgen-dependent and can be utilized as a new suitable model in the study of the mechanism of androgen on tumor development.

Androgens↗
PubMed1983

Forskolin activates adenylate cyclase activity and inhibits mitosis in in vitro in pig epidermis.

The novel adenylate cyclase activator forskolin caused rapid and high intracellular accumulation of cyclic AMP in a floating skin (epidermal) slice system. Increased cAMP levels were also detected in the media. Addition of a phosphodiesterase inhibitor to forskolin-containing medium caused only a slight increase in the intracellular cAMP level and forskolin itself did not inhibit phosphodiesterase activity. Ka of forskolin for epidermal adenylate cyclase was about 2-3 X 10(-5) M. This forskolin activation was rapidly reversed after washing. The forskolin stimulation (Ka 5 X 10(-5) M) was also found when tested with an epidermal membrane preparation which contained the catalytic unit of adenylate cyclase but lacked either the GTP or receptor stimulation. With the epidermal slice system, the combination of forskolin and epinephrine (or histamine) stimulated adenylate cyclase synergistically. The data suggest that forskolin activates not only the catalytic unit but also the nucleotide regulatory protein or the receptor-regulatory protein complex of the adenylate cyclase system. The cAMP accumulation caused by forskolin produced a dose-dependent mitotic inhibition of epidermal cells in an in vitro outgrowth system. This inhibitory effect was reversible 48 h after washing out the forskolin.

1-Methyl-3-isobutylxanthine↗
PubMed1982

Activity of 3 beta-hydroxysteroid dehydrogenase delta 4-5 isomerase in the human skin.

The activity of 3 beta-hydroxysteroid dehydrogenase delta 4-5 isomerase (3 beta-HSD) was assayed in various tissues microdissected from the freeze-dried human skin of 13 subjects. The sebaceous gland possessed the highest activity of 3 beta-HSD in the skin, while the apocrine sweat gland showed only one fourth of that activity. The vellus hair follicle showed nearly one half of the activity of the sebaceous gland, whereas the terminal hair follicle exhibited much lower activity. The activity of the epidermis and of the dermis were negligible. Incubation of fresh whole skin of the forehead with 7 alpha-3H-DHA and subsequent isolation of various tissues revealed that the metabolites identified in the sebaceous gland were androstanedione and androstenedione, whereas testosterone and/or dihydrotestosterone were not detected.

3-Hydroxysteroid Dehydrogenases↗
PubMed1982

Hormonal control of 5 alpha-reductase activity in hamster sebaceous glands.

The effect of castration on total 5 alpha-reductase activity in transforming testosterone to 5 alpha-reduced metabolites was studied in the sebaceous gland of male hamsters. The mean enzyme activity increased to more than twice the control level as early as 4 days after castration and this increase remained almost unchanged at 14, 21 and 63 days after castration. The administration of testosterone propionate or 5 alpha-dihydrotestosterone to castrates led to a complete inhibition of the increase in enzyme activity and this inhibitory effect was blocked by cyproterone acetate. These data indicate that androgens may be regulators of 5 alpha-reductase activity in the sebaceous gland of hamsters.

3-Oxo-5-alpha-Steroid 4-Dehydrogenase↗
PubMed1981

Activity of 17 beta-hydroxysteroid dehydrogenase in various tissues of human skin.

The activity of 17 beta-hydroxysteroid dehydrogenase (17 beta-HSD) was assayed in various tissues microdissected from the freeze-dried human skin of fourteen subjects. The apocrine sweat gland, sebaceous gland and hair follicle possessed a high activity of 17 beta-HSD. The enzyme activity was negligible in the epidermis, except that the scalp epidermis showed much the same activity as the hair follicle. The demis showed variable activity because of contamination with other components.

17-Hydroxysteroid Dehydrogenases↗
PubMed1980

Activity of testosterone 5 alpha-reductase in various tissues of human skin.

In order to know the distribution of testosterone 5 alpha-reductase activity in human skin, we developed a micro-method, in which we used 20-50 micrograms of various tissues microdissected from freeze-dried sections. The characteristics of this enzyme in the sebaceous gland are briefly described, as follows: the identified 5 alpha-reduced metabolites are 5 alpha-dihydrotestosterone, 5 alpha-androstane-3 beta, 17 beta-diol and 5 alpha-androstanedione; the optimal pH is about 7.5; and the apparent Km is approximately 2.4 x 10(-5) M. The measurement of 5 alpha-reductase activity of various components of the skin obtained from 7 men and 5 women revealed that the sweat gland (probably apocrine) in the axillary skin possessed the highest activity of 5 alpha-reductase: the value was nearly 400 pmoles/mg dry weight/hr in the standardized condition. The sebaceous gland also showed a high activity of 85-261 pmoles/mg/hr. The hair follicles exhibited a significantly lower activity than the sebaceous gland. The enzyme activity was negligible in the epidermis, while it was detected in the dermis though the values determined were variable probably because of contamination with other components such as sweat glands and hair follicles. Thus, the present study demonstrates that the 5 alpha-reductase activity is mainly located in the apocrine sweat gland and sebaceous gland. This suggests that 5 alpha-reduction of testosterone is an important step in mediating the action of androgens in these tissues.

3-Oxo-5-alpha-Steroid 4-Dehydrogenase↗
PubMed1980

Sweet's syndrome in infancy.

A 3-month-old Japanese girl developed tender erythematous elevated plaques on her face and buttocks with fever up to 38 degrees C. Histology showed a perivascular neutrophil infiltrate with nuclear debris in the dermis. Endothelial cells were swollen but no hyalinization of the vessel wall was observed. The lesions recurred several times and responded little to antibiotics but dramatically to oral corticosteroid. We diagnosed her skin condition as Sweet's syndrome in infancy.

Female↗