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Biomedical subjects

S Itami

Publications and source records attributed to S Itami.

At least 55 records · Page 3Linked to original sources

Expression of mRNA for androgen receptor, 5alpha-reductase and 17beta-hydroxysteroid dehydrogenase in human dermal papilla cells.

In order to determine whether adrenal and gonadal weak androgens are utilized to form active androgens in human hair, we studied the expression of mRNA for androgen receptor (AR), 5alpha-reductase and 17beta-hydroxysteroid dehydrogenase (17beta-HSD) in cultured dermal papilla cells (DPCs) from various body sites. AR mRNA was expressed in beard (Be) and axillary hair (Ax) DPCs from both sexes, but only at a low level in DPCs from occipital scalp hair (OS). Type I 5alpha-reductase mRNA was expressed by all DPCs. Type II 5alpha-reductase mRNA was identified in beard DPCs, but was absent from OS and Ax DPCs. Type II 17beta-HSD mRNA was strongly expressed in outer root sheath cells (ORSCs), while DPCs except for male Ax expressed no type II 17beta-HSD mRNA. In contrast, type III 17beta-HSD mRNA was strongly expressed in Be DPCs and Ax DPCs from both sexes; ORSCs showed a low level of expression. Expression of type III 17beta-HSD mRNA was not regulated by androgen in DPCs. These results suggest that the sensitivity of hairs to androgen is partially controlled by the site-specific expression of AR, 5alpha-reductase and 17beta-HSD in DPCs.

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

Regulation of keratin 9 in nonpalmoplantar keratinocytes by palmoplantar fibroblasts through epithelial-mesenchymal interactions.

Palms and soles differ from other body sites in terms of clinical and histologic appearance, response to mechanical stress, and the distribution of keratin 9. Because keratin 9 is exclusively expressed in the palmoplantar suprabasal keratinocyte layers, it is considered a differentiation marker of palms and soles. We studied palmoplantar mesenchymal influences on keratin 9 induction in nonpalmoplantar epidermis. Although palmoplantar keratinocytes when cultured alone continued to express keratin 9 mRNA in 12 (100%) of 12 cultures, nonpalmoplantar keratinocytes did not express it in 16 of 17 cultures. Although nonpalmoplantar keratinocytes did not express keratin 9 mRNA when cultured with nonpalmoplantar fibroblasts, they did express it within 2 h in cocultures with palmoplantar fibroblasts derived from papillary dermis. Grafting of these coculture sheets on severe combined immunodeficient mice resulted in an epidermis, which histologically showed hyperkeratosis and acanthosis and immunohistochemically expressed keratin 9. Furthermore, pure epidermal sheets from nonpalmoplantar skin grafted on the human sole wounds due to burn, injury, and the resection of acral lentiginous melanoma, demonstrated adoption of palmoplantar phenotype and expressed keratin 9. Our report indicates extrinsic keratin 9 regulation by signals from dermal fibroblasts. This is also the first to suggest the possibility of treating palmoplantar wounds with nonpalmoplantar epidermis, which is much easier to obtain and harvest.

Animals↗

Viability of isolated single hair follicles preserved at 4 degrees C.

BACKGROUND: Hair follicle preservation for the purpose of delayed application would help us to transplant hair follicles more efficiently. METHODS: Isolated single hair follicles were preserved at 4 degrees C in four different solutions. Viability of preserved follicles was judged by organ culture and cell culture. In addition, a small number of hair follicles were transplanted into athymic mice. RESULTS. By cell culture, both dermal papilla and outer root sheath cells could be cultivated after 7 days of preservation. Hair follicles preserved for 48 hours showed a significant increase of hair shafts in organ culture. Those preserved for 7 days regrew well when transplanted into athymic mice. CONCLUSION: Preservation of hair follicles at 4 degrees C could be one option to prepare many follicular units at one time for transplantation.

Adult↗

A case of giant axonal neuropathy showing focal aggregation and hypophosphorylation of intermediate filaments.

We report here the clinicopathological features of a typical case of giant axonal neuropathy (GAN). Scanning electron microscopy of the hair of this case revealed an extraordinarily irregular cuticle. Focal accumulation of intermediate filaments in axons, Schwann cells, muscle fibers and skin fibroblasts were also found under an electron microscopy. When examined immunocytochemically, muscle fibers exhibited local disruption of the filamentous network in the subsarcolemmal space and in the central cytoplasm accompanied by focal accumulation of desmin. The intracellular network of vimentin was also disrupted, exhibiting global accumulation in some of the cultured skin fibroblasts. Decreased interneurofilament spacing was found in enlarged axons, suggesting the presence of hypophosphorylation of neurofilaments in this patient. These findings suggest general disorganization, abnormal distribution and possible defective phosphorylation of intermediate filaments in GAN.

Axons↗

Growth stimulation of normal melanocytes and nevocellular nevus cells by gastrin releasing peptide (GRP).

In order to know the possible effects of gastrin releasing peptide (GRP) on nevus cells and melanocytes, we studied the effect of GRP on the proliferation of cultured human nevus cells and normal melanocytes. MTS assay showed that GRP stimulated the growth of viable melanocytes at 1000 ng/ml. GRP also stimulated the growth of nevus cells in a dose dependent manner and maximum stimulation was obtained at 100 ng/ml of GRP. GRP was less effective for growth stimulation of normal melanocytes than nevus cells. The cytoplasm of nevus cells were positively stained by polyclonal anti-GRP antibody. We also detected the expression of GRP and GRP receptor mRNAs in these cells by RT-PCR. These results suggest that GRP acts as an autocrine growth factor for nevus cells and normal melanocytes.

Cell Division↗

Candida is not involved in the development of of periungual psoriatic lesion.

Infection can be a trigger or an aggravating factor in psoriasis, and in particular, bacterial focal infection is well documented to exacerbate psoriasis presumably through its superantigen. Since fungi could produce superantigen as well, and periungual involvement is often seen in psoriatic patients, we examined if local Candida infection plays some pathogenetic role or not in periungual lesions. In 15 psoriatic patients with periungual involvement, Candida infection was examined by microscopic study, culture, and antifungal treatment. We found no evidence suggestive of the relationship between Candida and psoriatic changes in periungual area.

Adult↗

Taurin-conjugated ursodeoxycholic acid has a reversible inhibitory effect on human keratinocyte growth.

Tauroursodeoxycholic acid (TUDC) is one of the most hydrophilic taurin conjugated bile acids. TUDC has a suppressive effect on DNA synthesis in primary cultured rat hepatocytes. In this study, we investigated the growth inhibitory effect of TUDC on cultured human keratinocytes. TUDC suppressed the proliferation of keratinocytes in a dose dependent fashion, as measured by both cell counts and 5-bromo-2'-deoxyuridine (BrdU) uptake. Keratinocytes reproliferated and reached almost the same cell number as control after removal of TUDC from the medium. TUDC (1 mM) had no effect on the cell viability, as measured by the dye exclusion test. Epidermal sheets stratified in the presence of TUDC appeared thinner than those stratified without TUDC. These results suggest that TUDC has a reversible growth suppressive effect on human keratinocytes through the mechanism other than cytotoxicity and would be applicable for the treatment of hyperproliferative skin disorders such as psoriasis.

Animals↗

Predominance of type I 5alpha-reductase in apocrine sweat glands of patients with excessive or abnormal odour derived from apocrine sweat (osmidrosis).

High levels of 5alpha-reductase activity have been detected in human apocrine glands, and the concentration of dihydrotestosterone has been found to be higher than that of testosterone in the nuclear fraction of the skin of patients who suffer from excessive or abnormal odour derived from apocrine sweat (osmidrosis). Although these results suggest that 5alpha-reductase may play a central role in the action of androgens in the apocrine gland, the isozyme responsible is not known. We therefore assayed 5alpha-reductase type I and type II activity and mRNA expression in isolated apocrine glands from four patients with osmidrosis. When we incubated gland homogenates with [3H]testosterone, we found that the biochemical properties of the apocrine gland enzyme were consistent with those of type I 5alpha-reductase: at substrate concentrations of both 50 nmol/L and 1 micromol/L, the optimum pH was in the range 6.0-7.5, and the apparent Km was 21.1 micromol/L. The apocrine gland enzyme was inhibited by MK386, a specific inhibitor of type I 5alpha-reductase, in a dose-dependent manner, but it was hardly affected by finasteride, a specific inhibitor of type II isozyme, in that a nanomolar concentration of finasteride produced only a slight inhibition. Reverse transcriptase-polymerase chain reaction showed that the apocrine gland expressed type I 5alpha-reductase mRNA exclusively, except for a faint band of type II isozyme in a few preparations. These data indicate that the type I isozyme is the predominant form of 5alpha-reductase in the apocrine gland and may play a central role in the anabolic activity of androgens, as reported for the sebaceous gland. In addition, a small amount of type II isozyme may be expressed by mesenchymal cells that surround the apocrine glands and also contribute to their development.

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

Immunological study on CD3 defective cutaneous T cell lymphoma cells from a patient with Sézary syndrome.

Here we investigated the nature of cutaneous T cell lymphoma (CTCL) cells lacking surface CD3. A large number of CD3- CD4 T cells were found in the peripheral blood and lesional skin of a patient with Sézary syndrome, which is a variant of CTCL. Southern blot analysis revealed that a clonal rearrangement of T cell receptor (TCR) genes was detected in the separated CD3- CD4 cells, whereas CD3+ CD4 cells showed no clonal rearrangement, indicating that the CD3- CD4 cells represented CTCL cells. However, the CTCL cells expressed TCR with a particular Vbeta apart from CD3. The CTCL cells showed significant responses to staphylococcal enterotoxins (SEs) in vitro, although they hardly responded to phytohaemagglutinin, Mycobacterium tuberculosis antigen, and alloantigen. They required antigen-presenting cells (APC) to respond to SEB. Blocking analyses with MoAbs revealed that they recognized SEB through TCR depending on HLA-DR and intercellular adhesion molecule-1 (ICAM-1). Taken collectively, these results indicate that the CTCL cells lacking surface CD3 could proliferate in response to bacterial superantigens, whereas the responses to conventional antigens were generally suppressed. These results also implied that CTCL could be exacerbated by bacterial infection.

Antigen-Presenting Cells↗

Tissue-specific knockout of the mouse Pig-a gene reveals important roles for GPI-anchored proteins in skin development.

Glycosylphosphatidylinositol (GPI)-anchored proteins are widely distributed on plasma membranes of eukaryotes. More than 50 GPI-anchored proteins have been shown to be spatiotemporally expressed in mice with a deficiency of GPI-anchor biosynthesis that causes embryonic lethality. Here, we examine the functional roles of GPI-anchored proteins in mouse skin using the Cre-loxP recombination system. We disrupted the Pig-a gene, an X-linked gene essential for GPI-anchor biosynthesis, in skin. The Cre-mediated Pig-a disruption occurred in skin at almost 100% efficiency in male mice bearing two identically orientated loxP sites within the Pig-a gene. Expression of GPI-anchored proteins was completely absent in the skin of these mice. The skin of such mutants looked wrinkled and more scaly than that of wild-type mice. Furthermore, histological examination of mutant mice showed that the epidermal horny layer was tightly packed and thickened. Electron microscopy showed that the intercellular space was narrow and there were many small vesicles embedded in the intercellular space that were not observed in equivalent wild-type mouse skin preparations. Mutant mice died within a few days after birth, suggesting that Pig-a function is essential for proper skin differentiation and maintenance.

Animals↗

Increased levels of IL-13 mRNA, but not IL-4 mRNA, are found in vivo in peripheral blood mononuclear cells (PBMC) of patients with atopic dermatitis (AD).

Previous studies using in vitro systems with various stimuli have shown that PBMC from patients with AD show increased levels of IL-4 but decreased levels of interferon-gamma (IFN-gamma) compared with PBMC from normal controls. However, in vitro conditions do not always mimic the in vivo condition. We therefore believe that it is important to quantify the expression of these cytokines in freshly isolated PBMC. This study examines the expression of IFN-gamma, IL-4 and IL- 13 mRNA in freshly isolated PBMC from adult patients with AD, from patients with psoriasis vulgaris and from healthy adults, using the semiquantitative reverse transcriptase-polymerase chain reaction (RT-PCR) method. Levels of IFN-gamma mRNA were significantly lower in PBMC of patients with AD than in controls. IL-4 mRNA levels did not differ significantly between groups. Conversely, levels of mRNA for IL-13 were significantly greater in PBMC of patients with AD than in controls. An increase in IL-13 expression may regulate the in vivo synthesis of IgE in patients with AD.

Adolescent↗

Vitamin C abrogates the deleterious effects of UVB radiation on cutaneous immunity by a mechanism that does not depend on TNF-alpha.

Acute low-dose treatment of murine skin with ultra violet B (UVB) light impairs induction of contact hypersensitivity (CH) to dinitrofluorobenzene (DNFB) in certain inbred strains of mice (termed UVB-susceptible), but not in others (termed UVB-resistant), and promotes tolerance. These deleterious effects of ultraviolet radiation (UVR) are mediated in part by TNF-alpha, which is released from UVR-exposed epidermal and dermal cells. Because UVR damage to skin has also been ascribed in part to the generation of reactive oxygen intermediates (ROIs) such as superoxide anion (O2-), hydrogen peroxide (H2O2), hydroxyl radical (OH-), and singlet oxygen ((1)O2), we investigated whether vitamin C (ascorbic acid), which can nullify ROIs, prevents the deleterious effects of UVR on the cutaneous immune system. We found that epicutaneous application of vitamin C (10% L-ascorbic acid solution) abrogated the deleterious effects of acute low-dose UVR on induction of CH and prevented the induction of tolerance. Vitamin C, however, did not reverse the effects of TNF-alpha on CH induction and tolerance. These results indicate that (i) ROIs generated intracutaneously by UVR contribute to the impaired ability of exposed skin to support the induction of CH and to promote the induction of tolerance and (ii) these effects are not dependent on TNF-alpha.

Animals↗

Human genital melanocytes as androgen target cells.

As some parts of human skin - such as genital and areolar skin - become pigmented after puberty, melanocytes in these regions are thought to be sex hormone target cells. We immunohistochemically localized androgen receptors in the nuclei of cultured human genital melanocytes by monoclonal and polyclonal antibodies. When these cells were incubated with [1,2-3H]-testosterone, the major metabolite in the medium was dihydrotestosterone and 5alpha-reduction predominated over 17beta-oxidation. Androgen receptor and type I 5alpha-reductase mRNAs could be detected in genital melanocytes by reverse transcriptase polymerase chain reaction. The tyrosinase activity was stimulated by the addition of androgen. This stimulation was antagonized by cyproterone acetate, whereas tyrosinase mRNA expression was not affected by androgen. These results indicate that human genital melanocytes are androgen target cells, and that androgen plays a role for pigmentation in the specific regional skin after puberty.

17-Hydroxysteroid Dehydrogenases↗

OK-432 therapy for recalcitrant warts.

Twelve patients with warts recalcitrant to various treatment, including cryotherapy, were treated with OK-432 injection therapy. Six patients received only subcutaneous injection, three received only intralesional injection, and the other three received both subcutaneous and intralesional injections. Complete clearing of the warts occurred in nine (75%) of 12 patients, while the other three patients were not cured. Grouping the patients by the method of injection, the success rate of subcutaneous injection was 5/9 (55.6%), and that of intralesional injection was 4/6 (66.7%). Although five patients complained of mild fever and malaise, these side effects gradually disappeared during the repeated injections. OK-432 injection is considered as a hopeful therapy for recalcitrant warts.

Adolescent↗

Perineural and neural involvement in skin cancers.

BACKGROUND: Malignant skin tumors rarely spread along nerves. Complete resection of involved nerves is often unsuccessful. OBJECTIVE: In the treatment of tumors with perineural invasion, surgeons should accurately estimate the extent of distant spread. METHODS: We report six cases of skin cancers, including two basal cell carcinomas, two squamous cell carcinomas, and two neurotropic malignant melanomas, that invaded nerve or perineural spaces. RESULTS: In three of the cases, the tumors developed on the face and involved the infraorbital nerves or its branches. Two patients suffered from tumors on old burn scars of lower legs. Branches of posttibal nerves were involved in both cases. In the last case, tumor invasion of a branch of the greater occipital nerve was detected. CONCLUSION: The extent of surgical excision should include the area of skin supplied by the affected nerve, which must be resected in continuity.

Adult↗