Human external ear canal as the specific reservoir of Malassezia slooffiae.

The incidence of Malassezia species recovered from the external ear canal was characterized using culture medium optimized for Malassezia spp., CHROMagar Malassezia. The results of this study indicated that in healthy individuals M. slooffiae was the dominant Malassezia species followed by M. restricta.

[A study of otitis externa associated with Malassezia].

Malassezia-positive smears can be recognized from otitis externa, however, there are few references in the literature to the relation between Malassezia and otitis externa. Therefore, the bacterial and clinical characteristics of 72 cases (63 patients) with otitis externa were investigated at the Department of Otorhinolaryngology, Takinomiya General Hospital to analyze this. Thirty-seven cases were bacterial otitis externa, 20 cases were fungal otitis externa, and 15 cases were etiological agents unknown in this study. The causative organisms in fungal otitis externa were the genera Aspergillus (10 cases), Malassezia (5) and Candida (5), respectively. We suspected that 5 cases were caused by Malassezia because Malassezia cell counts were greater than 10 per field (x 400), and a large number of Malassezia were isolated from all cases. In these cases, many squamous epithelial cells were observed by direct examination, and cells from the middle or basal layer of the ear canal were also recognized in three cases. Therefore, accelerated turnover of epidermal cells of the ear canal was suggested. The main symptoms were itching and fullness in the ear, with observations of redness and erosion in objective deterioration, and we felt that these conditions were similar to seborrheic dermatitis (SD). In addition, these five cases were confirmed as fungus-related otitis externa by their improvement with antifungal agents.

Aging exacerbates restraint stress-induced inhibition of antigen-specific antibody production in mice.

BACKGROUND: We have recently found that exposure to acute restraint stress suppresses antigen-specific antibody production, including IgE, in a murine model of allergic rhinitis. Although age-related alterations in immune responses are known, it remains unclear whether aging modulates the antibody production under stressful conditions. In this study, we set out to determine the effects of aging on antibody production under acute restraint stress in mice. METHODS: Both young and aged CBA/J mice were repeatedly sensitized intranasally with phospholipase A2 (PLA2) without adjuvants. Restraint stress was applied using uniform cylinders once a week for a continuous 8h period, on 5 occasions in total. Blood samples were taken at 0, 20 and 30 days after primary sensitization, and production of PLA2-specific antibodies and levels of IL-4, IFN-gamma, IL-10 and IL-1 beta in sera were determined by ELISA. RESULTS: Repeated intranasal sensitization with PLA2 induced PLA2-specific IgE, IgG1 and IgG2a production in aged mice. We found that exposure to restraint stress significantly inhibited production of PLA2-specific IgE, IgG1 and IgG2a in aged mice. In addition, antibody production under restraint stress decreased significantly in aged mice when compared with young mice. No IL-4, IFN-gamma, IL-10 or IL-1 beta were detected in sera from non-stressed or stressed aged mice. CONCLUSIONS: Aging exacerbates the immunosuppressive role of acute restraint stress in antigen-specific antibody production in mice.

Immunosuppressive effect of restraint stress on the initiation of allergic rhinitis in mice.

BACKGROUND: Exposure to acute stressors modulates both innate and acquired immune function. However, little is known about whether stress has the potential to modulate the pathogenesis of allergic rhinitis. OBJECTIVES: To determine the effects of acute restraint stress on the initiation of allergic rhinitis in a murine model. METHODS: CBA/J mice were repeatedly intranasally sensitized with phospholipase A2 (PLA2) from honeybee venom without adjuvant. Restraint stress was applied using uniform cylinders once a week for a continuous 8-hour period, on five occasions in total. Production of PLA2-specific antibodies and degree of nasal and blood eosinophilia were compared between stressed and control mice. RESULTS: Repeated intranasal sensitization with PLA2 induced PLA2-specific IgE and marked eosinophilia in both the nose and blood in CBA/J mice. Exposure to restraint stress significantly inhibited production of PLA2-specific IgE, IgG1 and IgG2a. Conversely, the stress exerted no significant effect on eosinophilia. CONCLUSIONS: Exposure to acute restraint stress inhibits antigen-specific antibody production, but not local or systemic eosinophilia. The results of this study suggest that acute stress has the potential to modulate the initiation of allergic rhinitis.

Role of macrophage migration inhibitory factor in otitis media with effusion in adults.

Otitis media with effusion (OME) is one of the most common ear diseases. Bacterial endotoxins and several inflammatory cytokines appear to be involved in the pathogenesis of OME in children; however, little is known of the immunological aspects of the onset of OME in adults. We sought to determine the presence of macrophage migration inhibitory factor (MIF) as well as interleukin 1beta (IL-1beta), tumor necrosis factor alpha (TNF-alpha), RANTES (regulated upon activation, normal T-cell expressed and presumably secreted), and endotoxin in middle ear effusions (MEEs) from adult patients with OME. In addition, the levels of MIF in MEEs from adults and children were compared. MEE was obtained from 95 adults and 11 children. The levels of MIF, IL-1beta, TNF-alpha, and RANTES were determined by enzyme-linked immunosorbent assay, and the concentrations of endotoxin and total protein were determined by the Endospec assay and bicinchoninic acid assay, respectively. MIF was detected in 97.9% of the MEEs from adults, while endotoxin, IL-1beta, TNF-alpha, and RANTES were detected in 96.8, 12.6, 5.3, and 43.9%, respectively. In addition, the level of MIF was significantly higher than those of endotoxin, IL-1beta, and TNF-alpha. A positive correlation between the levels of MIF and endotoxin was observed. MIF and endotoxin were detected in 81.8 and 72.7%, respectively, of the MEEs from the children. The level of MIF was significantly higher in the children, and conversely that of endotoxin was significantly higher in the adults. These results suggest that the interaction between MIF and endotoxin may promote fluid collection in the middle ear, particularly in adults.