Ryoji Tsuboi

Comparative Study of Staphylococcus aureus Isolated from Lesional and Non-Lesional Skin of Atopic Dermatitis Patients

The skin of patients with atopic dermatitis (AD) is often colonized by Staphylococcus aureus, and superantigenic exotoxins produced by the organism are thought to be an important precipitating factor of AD. However, there are few reports comparing the characteristics of S. aureus isolated from the lesional and non‐lesional skin of identical AD patients. In this study, therefore, we examined whether the presence of superantigen‐producing S. aureus correlates with the formation of eczematous lesion of AD patients. The detection rate of S. aureus on the lesional skin of AD patients was higher than on the non‐lesional skin of AD patients. Furthermore, the bacterial cell count of S. aureus on the lesional skin of AD patients was also significantly higher than that of the non‐lesional skin of AD patients. However, there was no significant difference between the detection rate of superantigenic exotoxin‐producing S. aureus on the lesional and non‐lesional skin of AD patients. These results suggest that the number of S. aureus present is more important in the formation of eczematous lesion of AD patients than the presence of superantigenic exotoxin‐producing S. aureus strains per se.

A Wound Healing Model Using Healing‐impaired Diabetic Mice

A quantitative histological approach was employed to evaluate the effects of basic fibroblast growth factor (bFGF) in healing‐impaired diabetic mice. The dorsal areas of female mutant diabetic mice, C57BL KsJ db/db (Jackson Lab.), were given two 6 mm‐size full thickness wounds with a punch biopsy instrument. After application of bFGF, the wounds were left open. 8 days after wounding, the mice were sacrificed, and histological sections were evaluated using several histological parameters, such as the degree of wound closure, granulation tissue thickness, matrix density, and capillary numbers.

Topical Application of Ketoconazole Stimulates Hair Growth in C3H/HeN Mice

Ketoconazole (KCZ) is an imidazole anti‐fungal agent that is also effective in topical applications for treating seborrheic dermatitis and dandruff. Recently, topical use of 2% KCZ shampoo has been reported to have had a clinically therapeutic effect on androgenetic alopecia. The present study was conducted with the purpose of quantitatively examining the stimulatory effect of KCZ on hair growth in a mouse model. Coat hairs on the dorsal skin of seven week‐old male C3H/HeN mice were gently clipped, and either 2% KCZ solution in 95% ethanol or a vehicle solution was topically applied once daily for three weeks. The clipped area was photographed, and the ratio of re‐grown coat area was then calculated. The results demonstrated that 2% KCZ had a macroscopically significant stimulatory effect compared with the vehicle group (p<0.01, n=10). Repeated experiments showed similar effects, confirming the efficacy of KCZ as a hair growth stimulant. Although the therapeutic mechanism of topical KCZ for hair growth is unclear, our results suggest that topical applications of the substance are useful for treating seborrheic dermatitis accompanied by hair regression or male pattern hair loss.

Genes for a range of growth factors and cyclin-dependent kinase inhibitors are expressed by isolated human hair follicles

Summary The mRNA expressions of various growth regulatory molecules in single human anagen hair follicles were analysed by reverse transcription and polymerase chain reaction. Approximately 370 hair follicles were isolated from 20 normal individuals, and 0.90 ± 0.34 μg (mean ± SD) total RNA was extracted per whole hair follicle. The mRNAs of fibroblast growth factor (FGF)‐l, FGF‐2, FGl‐5. FGF‐7, transforming growth factor (TGF)‐α. TGF‐β1. hepatocyte growth factor, insulin‐like growth factor (IGF)‐I. tumour suppressor gene p53 and high sulphur protein were detected in most or all of the examined hair follicles per target gene. In contrast, none of the mRNAs of FGF‐3, FGF‐4, FGF‐6, FGF‐9 and IGF‐II was detected, and those of TGF‐β2 and TGF‐β3 were detected in only a limited number of the examined hair follicles. Among cyclin‐dependent kinase inhibitors, the mRNAs of p2lwaf1/cip1 and p27kipl were expressed in almost all the hair follicles, while those of p15INK4B and p161NK4A were not detected. These results suggest that both positive and negative factors for the proliferation and differentiation of follicular epithelial cells coexist in a human anagen hair follicle.

Stimulation of Keratinocyte Migration by Growth Factors

Migration of keratinocytes from the wound edge is thought to be one of the critical features of reepithelialization. A quantitative migration assay was carried out using normal human keratinocytes. Keratinocytes, seeded on 12 well plates, were grown in serum free, keratinocyte growth medium (KGM, Curabo Co) with 0.08mM Ca++. The medium was switched from KGM to keratinocyte basal medium (KBM) 6 h prior to the wounding. Half of the plates confluent monolayer of keratinocytes was removed with a razor blade, and the remaining keratinocytes were incubated in KBM for 16 hrs in the presence of indicated growth factors. After incubation, the cells were fixed and counted at 100 magnification. Migration was quantitated by counting the number of cells in ten successive 125‐μm zones.

Molecular detection of dermatophytes and nondermatophytes in onychomycosis by nested polymerase chain reaction based on 28S ribosomal RNA gene sequences

Backgroundu2002 Onychomycosis is often caused by dermatophytes, but the role of nondermatophytes is underestimated due to the difficulty of identifying them by conventional direct microscopy and culture.

The effect of hepatocyte growth factor/scatter factor on human hair follicle growth

The effect of hepatocyte growth factor/scatter factor (HGF/SF) on human hair follicle growth was examined using a serum-free organ culture system. The DNA synthesis in human hair follicles and elongation of the hair shaft were measured subsequent to the follicle isolation and culture at 31 degrees C in 95% O2-5% CO2 for 72 h. Results showed that HGF/SF significantly increased 3H-thymidine (P < 0.001) incorporation and hair follicle length (P < 0.05). The effect of HGF/SF was dose-dependent with a maximal stimulation at 10 ng/ml.

Transforming growth factor‐bβ1 suppresses atopic dermatitis‐like skin lesions in NC/Nga mice

Atopic dermatitis is a chronic, relapsing inflammatory disorder characterized by pruritic and eczematous skin lesions. Transforming growth factor (TGF)‐β1 has been implicated in the suppression of inflammatory responses.

A case of ichthyosis linearis circumflexa successfully treated with topical tacrolimus

We report a case of ichthyosis linearis circumflexa (ILC) without the typical atopic manifestations and deformities of the hair shaft. The patient responded positively to treatment with topical tacrolimus, suggesting that abnormalities in the immunoregulatory mechanism may be involved in the pathogenesis of ILC.

Hepatocyte growth factor (HGF) activator expressed in hair follicles is involved in in vitro HGF-dependent hair follicle elongation

Hepatocyte growth factor (HGF), a paracrine factor secreted by follicular papilla cells, acts on neighboring follicular epithelial cells to promote follicular growth, while HGF activator is a serine proteinase, which converts inactive single-chain HGF to the active heterodimeric form. In this study, using 3 rapid amplification of cDNA end/nested polymerase chain reaction (3 RACE/nested PCR) and immunoblotting, we confirmed the expression of HGF activator in both cultured human follicular papilla cells and outer root sheath cells. HGF activator mRNA was expressed in all of the isolated 15 anagen hair follicles taken from the scalps of seven individuals. In an organ culture system, single-chain HGF stimulated hair follicle elongation, which was partially inhibited by aprotinin, a serine proteinase inhibitor (P<0.01). These results suggest that single-chain HGF secreted from follicular papilla cells is converted to an active heterodimeric form by intrinsic HGF activator and that the resultant active form of HGF stimulates hair growth.