Jirô Arata

Correlation between expression of peroxisome proliferator-activated receptor β and squamous differentiation in epidermal and tracheobronchial epithelial cells

Previously, several members of the nuclear receptor superfamily have been implicated in the regulation of epidermal differentiation. In this study, we analyze the expression of members of the PPAR nuclear receptor subfamily in relation to the process of squamous differentiation in normal human epidermal keratinocytes (NHEK), human tracheobronchial epithelial (HBE) cells and the epidermis in vivo. Our results demonstrate that induction of differentiation in NHEK by either treatment with the phorbol ester phorbol 12-myristate-13-acetate (PMA), suspension culture or confluence greatly enhances the expression of PPARbeta mRNA. Likewise, topical treatment of mouse skin with PMA results in increased PPARbeta mRNA expression in the epidermis. In addition, the induction of squamous differentiation in HBE cells was also associated with an upregulation of PPARbeta mRNA expression. Finally, in situ hybridization analysis localized PPARbeta mRNA to the suprabasal layers of normal human skin. Our results demonstrate that the expression of PPARbeta is associated with squamous differentiation suggesting a regulatory role for this receptor in the control of specific genes during this differentiation process.

Effects of zinc oxide on the attachment of Staphylococcus aureus strains

We examined the attachment of Staphylococcus aureus to plastic tissue-culture coverslips after incubation for 24 h. The attachment to coverslips was weaker in rabbit plasma with 5% zinc oxide (ZnO) than in the control rabbit plasma without ZnO (P < 0.01). Plasma coagulation by S. aureus strains was not detected in plasma with 5% ZnO after incubation for 24 h. The membranous structure (an immature biofilm) was formed on the coverslips by S. aureus cells in plasma after incubation for 24 h. The colony counts of S. aureus cells on the membranous structures were lower in plasma with 5% ZnO, plasma with 0.2% hinokitiol, plasma with 5% ZnO + 0.2% hinokitiol, plasma with cefdinir at 4 minimum inhibitory concentration (MIC) and plasma with levofloxacin at 4 MIC, than in the control plasma after incubation for 24 h (P < 0.01). The colonies on the membranous structures completely disappeared in the case of plasma with 5% ZnO and 0.2% hinokitiol. The colony counts on membranous structures were lower in plasma with cefdinir at 4 MIC or levofloxacin at 4 MIC containing 5% ZnO than in plasma with cefdinir at 4 MIC or levofloxacin at 4 MIC only, (P < 0.05). The MICs of hinokitiol against S. aureus strains peaked at an MIC distribution of 16-32 micrograms/ml. The peak shifted to below 1 microgram/ml by adding 5% ZnO in agar plate method. The results suggest that the attachment of S. aureus cells to the coverslips is suppressed in the presence of 5% ZnO and that antistaphylococcal activities of cefdinir, levofloxacin and hinokitiol increase in the presence of 5% ZnO.

Staphylococcus aureus infection on cut wounds in the mouse skin : experimental staphylococcal botryomycosis

Staphylococcus aureus cells were inoculated on the cut wounds in the skin of cyclophosphamide-treated mice. Biopsy specimens were taken from three mice at 1, 3, 6, 12, 24, 36, 48 and 60 h after the inoculation and were examined by light and electron microscopies. One hour after the inoculation Staphylococcus aureus cells were seen around the cut wound and deeper into the subcutaneous tissue. By 6 h after the inoculation, Staphylococcus aureus cells formed clusters of bacterial colonies. By 36 h after the inoculation inflammatory cells, mainly polymorphonuclear leukocytes and macrophages, were seen around the clusters. Electron microscopic examination revealed fibril-like structures around the Staphylococcus aureus cells at 1 h. The Staphylococcus aureus cells were enclosed in membrane-like structures at 3 h. The membrane-like structures and the fibril-like structures were positive for Ruthenium red. By 12 h after the inoculation, the membrane-like structures increased in thickness and in electron density. Inflammatory cells were seen around but outside of the membrane-like structures at 24, 36 and 48 h. At 60 h the tissues around the membrane-like structures were degenerated and almost necrotic. These results suggest that Staphylococcus aureus cells may form biofilm in dermal or subcutaneous tissues in a neutropenic condition.

Expression of keratins (K10 and K17) in steatocystoma multiplex, eruptive vellus hair cysts, and epidermoid and trichilemmal cysts.

We compared the patterns of keratin 10 (K10) and keratin 17 (K17) expression in epidermoid cysts, trichilemmal cysts, eruptive vellus hair cysts, and steatocystoma multiplex. Epidermoid cysts expressed K10 and eruptive vellus hair cysts expressed K17, whereas trichilemmal cysts and steatocystoma multiplex showed expression of both K10 and K17. Our findings support the opinion that eruptive vellus hair cysts, which stained negative for K10, and steatocystoma multiplex are distinct entities and not variants of one disorder.

Linear lupus erythematosus profundus in a child

A 9-year-old Japanese boy had a 6-year history of a linear eruption of the left leg. It was characterized histopathologically by an intense lymphocytic panniculitis, perivascular and periappendageal infiltrates of lymphocytes, and vacuolization of the basal cell layer. This case represents a clinical presentation of linear lupus erythematosus profundus not previously reported.

Biofilm formation of Staphylococcus aureus strains isolated from impetigo and furuncle: role of fibrinogen and fibrin

The formation of membranous structure (thickness from the plastic tissue-culture coverslip (hematoxylin-eosin) > 1 mm; periodic acid-Schiff-positive) was more prominent with Staphylococcus aureus (S. aureus) strains isolated from impetigo (coagulase types I.V origin) than with S. aureus strains isolated from furuncle (coagulase type IV origin) (P < 0.05) in the plastic tissue-culture coverslip in human plasma after 72 h. Attachment of S. aureus cells to a plastic tissue-culture coverslip was more marked in 0-3% fibrinogen/tryptic soy broth (TSB) than in plasma (P < 0.05). The formation of the membranous structure was observed on the plastic tissue-culture coverslip with 0.3% fibrinogen/human serum but not with 0.3% fibrinogen + 5% glucose/TSB. Electron microscopy revealed abundant fibrin around S. aureus cells at 4 h and Ruthenium red-positive materials increased at 24 and 72 h in plasma. Staphylococcus aureus cell attachment to the plastic tissue-culture coverslip in plasma decreased by addition of levofloxacin (LVFX) at 1/2 minimum inhibitory concentration (MIC) and clarithromycin (CAM) at 1/4 MIC. Polysaccharide production of S. aureus cells on the plastic tissue-culture coverslip in plasma decreased with the addition of CAM at 1/4 MIC. Fibrinogen is closely related to initiation of infection but biofilm formation requires the conversion of fibrinogen to fibrin. Thus, attachment of S. aureus cells to the plastic tissue-culture coverslip, conversion of fibrinogen to fibrin by coagulase-prothrombin complex, and production of abundant glycocalyx by S. aureus cells are at least required for the production of biofilm in staphylococcal skin infection.

Dynamic alteration of human β-defensin 2 localization from cytoplasm to intercellular space in psoriatic skin

Abstract. Defensins are cationic antimicrobial peptides with a broad spectrum. Recently human β-defensin 2 (hBD-2) has been isolated from psoriatic skin; however, its exact localization and fate have not been fully understood. We studied the distribution pattern of hBD-2 in skin tissues of psoriasis and other inflammatory skin diseases. In the upper spinous and granular layer of psoriasis vulgaris hBD-2 was present in the cytoplasm. In the horny layer the positive signals were in a basket-weave pattern, indicating possible accumulation of hBD-2 in the intercellular space. The similar pattern of hBD-2 distribution was observed in the lesions of nummular eczema and atopic dermatitis. hBD-2 was not detected in the section of normal elbow and knee skin. When isolated psoriatic scales were stained, hBD-2 was detected in a wrapping paper-like distribution pattern surrounding the corneocytes. In horny layer of psoriatic skin hBD-2 was closely associated or colocalized with elafin, which is known to be in extracellular space, as demonstrated by double staining. Western blot analysis using cultured human keratinocytes detected hBD-2 with an expected size in the conditioned medium and in the cell lysates when stimulated with 5% FCS or IL-α. These results indicate that hBD-2 was synthesized and remained in cytoplasm in the upper spinous and granular layer, and then secreted into intercellular space in the horny layer. This dynamic change in hBD-2 distribution in epidermis is certainly relevant to function as an innate host defense mechanism against invading micro-organisms.

Adherence characteristics and susceptibility to antimicrobial agents of Staphylococcus aureus strains isolated from skin infections and atopic dermatitis

We examined the adherence characteristics and susceptibility to various antimicrobial agents of 130 strains of Staphylococcus aureus isolated from infective skin lesions and 135 strains of S. aureus isolated from non-infective eczematous lesions of atopic dermatitis (AD) patients. The isolation rate of methicillin-resistant S. aureus (MRSA) was 27.7% in strains from clinical sources excluding AD and 31.1% in those from AD. Coagulase type II strains were most frequently observed in MRSA strains isolated from all sources excluding AD, and coagulase type III strains were most frequently observed in those isolated from AD. We proposed that antimicrobial treatment for AD patients should be carefully designed to prevent MRSA infection. Plasma coagulation ability was lowest in S. aureus strains isolated from abscesses, suggesting that the lower production of fibrin observed in abscesses may assist the infiltration of neutrophils into skin tissues and that a decrease in plasma coagulation ability may enable abscess formation. Adherence to polypropylene tubes with slime production was most evident in S. aureus strains isolated from felon and least evident in those isolated from cellulitis and lymphangitis. Tube adherence was characteristic of the S. aureus strains attached to superficial skin tissues, but not necessarily for strains that had infiltrated the deep skin tissues. Fusidic acid demonstrated significant antimicrobial activity against the MRSA strains, but rifampicin was the strongest antimicrobial agent.

Nasal and nasal-type natural killer/ T–cell lymphoma☆☆☆

Nasal and nasal-type natural killer (NK)/T-cell lymphomas follow an aggressive course and have a poor prognosis. Recent pathologic studies suggest that the disease is a malignant proliferation of NK cells, which often express CD56. An association with the Epstein-Barr virus has also been reported. Skin involvement occurred in each of the 3 patients studied. Radiation therapy provided some benefit to the patients in the early stages. Conventional chemotherapies were not effective. To overcome this multiple-drug resistance of the tumor cells, cyclosporine and high-dose chemotherapy was combined with peripheral-blood stem-cell transplantation. The average life span from the onset of the disease for our patients was 9.6 months. Further improvement in the management of nasal and nasal-type NK/T-cell lymphomas is necessary.

Changes in Staphylococcus aureus density and lesion severity after topical application of povidone-iodine in cases of atopic dermatitis

A case-control study was performed to examine the efficacy of 10% povidone-iodine solution applied to atopic dermatitis patients. The density of Staphylococcus aureus on the eczematous lesions and the lesion severity before and after the topical application of povidone-iodine were compared. We found a 10-100-fold decrease in the density of S. aureus after povidone-iodine treatment in patients colonizing S. aureus at an initial density of > 1000 CFU/10 cm2. Erythema and exudation also decreased after povidone-iodine treatment in patients colonizing S. aureus at an initial density of > 1000 CFU/10 cm2. The 10% povidone-iodine solution disinfected S. aureus cells when added immediately after the cells were mixed in human plasma; however, 10% povidone-iodine solution only reduced the density of S. aureus cells by 10-100-fold when S. aureus cells were harvested after a 24 h incubation in human plasma. Staphylococcus aureus cells harvested after 24 h incubation in human plasma were often surrounded by fibrin bundles and cells circumscribed by fibrin bundles could not be disinfected with 10% povidone-iodine solution. We suggest that S. aureus cells may produce biofilm-like structures in atopic dermatitis patients and that these structures may help S. aureus cells resist the 10% povidone-iodine treatment.