Genusmalassezia are now divided to fourteen species. Different species will start or aggravate different skin diseases.
In the seborrheic dermatitis, M.restricta will play an important role, in the atopic dermatitis, M.globosa and/or M.restricta are major cutaneous microflora. The availability of new tools such as genomic and proteomic analyses has begun to provide a new insight into the pathogenetic mechanisms involved.

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[in Japanese]

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To improve the ability of dermatologists to diagnose cutaneous mycoses, we have proposed a list of the minimum mycological knowledge and skills required by senior residents of dermatology. The list includes ability to select the most appropriate sampling method, knowledge of the basic method of potassium hydroxide (KOH) examination and skill in performing fungal cultures and identifying the most prevalent fungal species isolated from skin lesions. It is not possible for the Japanese Society of Medical Mycology to train every senior resident directly, and it is difficult for them to acquire sufficient expertise independently. Consequently, training and advice given by instructors in residents' home institutes is essential. A project of an advanced course for instructors, who are in charge of educating senior residents in their own institute, may be possible. Therefore, we have proposed here a list for instructors of the knowledge and skills required to educate senior residents. Employing this list should realize improved skill in dermatologists.

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Electron microscopic techniques have been widely used to investigate the pathogenesis of dermatophytosis. In this article, morphological studies by scanning electron microscopy (SEM) and transmission electron microscopy (TEM) concerned with the dermatophyte infection process are literary reviewed and we introduced our morphological study observing the parasitic form of dermatophytes in the lesional cornified layer. Various experimental models have been established to study fungal adhesion and invasion to the skin surface in the early stage of infection by several authors.In these studies, arthroconidial adherence to corneocytes and germination was demonstrated by SEM and TEM. To understand the host-fungus relationship in dermatophytosis, it is also important to identify parasitic forms of fungi and morphological changes of corneocytes in the lesion. The three-dimensional structure of growing or parasitic dermatophytes in the lesional cornified cell layer was observed using the adhesive strip method in tinea cruris and tinea glabrosa. In tinea unguium, however, it is difficult to apply this method because of subungual hyperkeratosis. We introduce the alkaline treatment method for SEM for use in observing fungal elements in a subungual hyperkeratotic lesion and scales in dermatophytosis. With this technique, small pieces of nails or scales were fixed with 2.5% glutaraldehyde, and were treated with low concentrations of alkaline and subjected to the conventional procedure for SEM observation. This method is applicable to various skin lesions, such as tinea unguium, tinea pedis and tinea capitis to investigate the parasitic forms of dermatophytes and the spatial relationship with corneocytes and is useful to understand the infection process of dermatophytosis.

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Neutrophil accumulation is a critical event in the pathogenesis of inflammation. The generation of hypochlorous acid by myeloperoxidase (MPO) in neutrophils is crucial to the host defense response. MPO-deficient (MPO-KO) mice showed severely reduced cytotoxicity to Candida albicans, Aspergillus fumigatus, Cryptococcus neoformans and other microorganisms, demonstrating that an MPO-dependent oxidative system is important for in vivo host defense against fungi. On the other hand, impaired reactive oxygen species (ROS) production by neutrophils has previously been shown to cause an abnormal inflammatory response. In the present study, we have found that MPO-KO mice exhibit more severe pulmonary inflammation than wild-type mice when challenged with an intranasal administration of zymosan. In addition to measuring the kinetics of neutrophil accumulation, we also measured the production of macrophage inflammatory protein-2 (MIP-2) in the lung, and we correlate the degree of neutrophil accumulation with the production of this mediator. Our results demonstrate that MPO regulates the production of MIP-2, which may modulate neutrophil accumulation during lung inflammation.

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To evaluate the effect of the thiocarbamate antifungal agent liranaftate on inflammation and itchiness, footpad edema by phorbol 12-myristate 13-acetate (PMA) and the paw-licking accompanying by perceptual stimuli by compound 48/80 were examined. The effect of liranaftate application to mouse footpad on paw-licking time by compound 48/80 was observed. Topical administration of 4% liranaftate 1 hr before compound 48/80 did not suppress the paw-licking time, while pyrilamine, an anti-histamine agent, suppressed it significantly. As liranaftate was reported to suppress the ear inflammation induced by PMA, the effect of this agent on the footpad edema by PMA was examined. Liranaftate application significantly suppressed the increase in footpad swelling 24 hr after application of PMA, as true with ear inflammation. In this condition, we measured the paw-licking time by compound 48/80, but the suppression of time was not observed by the agent with or without the suppression of footpad inflammation. From these observations, we conclude that liranaftate treatment suppresses late phase inflammatory reaction in feet, perhaps accompanied by cytokine production, though it may not relieve acute stimuli and itchiness through an anti-histamine effect directly.

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Certain species of Candida are known as opportunistic fungal pathogens and Candida albicans has especially been isolated oral candidiasis patients at high frequency as a result of its strong pathogenicity. Recently C. dubliniensis is isolated mainly from immunocompromised patients, but is also detected from healthy persons. C. dubliniensis has similar cell morphology and molecular biological properties to C. albicans. Thus, in order to clarify the pathogenicity of C. dubliniensis, the activities of two extracellular enzymes, phospholipase (PL) and proteinase (PT), were measured, and pathological features were compared using mice. PL activity was examined in the improved Price's PL activity assay. In brief, the white precipitation zone was detected by spraying NaCl on egg yold plates without NaCl after colonies had grown. PL activity was no detected in any of the 31 C. dubliniensis strains tested. On the other hand, PT acitivty of C. dubliniensis was almost equivalent to that of C. albicans. Although we attempted to make an experimental model of mouse oral candidiasis using C. dubliniensis in yeast form as an inoculum following the conventional method, oral candidiasis did not develop in any mice. Thrush was successfully developed after inoculation with mycelial form cells, and there was no significant difference in histopathological findings of the thrush in comparison with C. albicans. These results strongly suggest that the two enzymes, PT and PL, do not play a crusial role in the establishment of mouse oral experimental candidiasis by C. dubliniensis.

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