H. Mittag

Fine structural investigation of Malassezia furfur. II. The envelope of the yeast cells

Summary. The general ultrastructure of the Malassezia furfur cell envelope is shown in a schematic model. Distinct layers such as the outer lamella, the cell wall and the plasma membrane and special structural elements of the cell wall are described and presented in electronmicrographs. Special attention was paid to the outer lamellar layer that seems to be equivalent to a capsule. It probably contains lipids as well as the cell wall, and it seems to participate in attachment processes.

Fine structural investigation of Malassezia furfur: I. Size and shape of the yeast cells and a consideration of their ploidy

Summary. Small and medium sized yeast cells of cylindrical or oval shape predominated in two Malassezia furfur‐standard strains CBS 1878 and CBS 6001 during the exponential growth phase. Large cells of wide‐oval shape were rare. They were encountered at the beginning of the stationary phase in strain CBS 6001, which also tended to form filaments easily. In the scales of pityriasis versicolor, there were large wide‐oval or spherical cells besides small and medium sized yeast cells and hyphal filaments. Considering the variable size and shape of the yeast cells, differences of their ploidy seemed likely, as described in other fungal species. This aspect is supported by the surface/volume quotient.

The fine structure of Hortaea werneckii

Summary. Hortaea werneckii (strain CBS 107.67) was examined by light and transmission electron microscopy (TEM). Special attention was paid to the wall architecture, the septum with a simple pore apparatus, the annellidic type of collar and the nuclei. Two‐celled organisms showed signs of distoseptation; nuclear events appeared to be rather synchronous in both cells. The fine structural results provided evidence of endogenous conidia development.

Structural alterations in Candida albicans by caffeine and caffeine salts.

Cytological alterations of Candida albicans following exposure to subinhibitory concentrations of caffeine and caffeine salts were examined by light and transmission electron microscopy (TEM). The effect was different from that induced by ketoconazole. Caffeine and especially caffeine salts caused an increase in unusual modes of proliferation with signs of multiple budding in Candida albicans. Structurally, such yeast cells present some resemblance to Paracoccidioides brasiliensis.

Langerhans cells in granulomatous syphilis

SummaryIn a case of granulomatous syphilis (transitional state between early and late syphilis), several Langerhans cells (LC) were present in the basal and medial part of the epidermis. Evidence of LC activation was given by the presence of many Langerhans granules, vesicles, a large Golgi apparatus and, sometimes, Golgi complexes. In some LC, signs of degeneration were visible. Langerhans granules surrounded by cytoplasmic material were present in the intercellular space of the epidermis. Apposition of lymphocytes to LC in the dermal space supports the role of LC in immunologic mechanisms. This was further confirmed by signs of phagocytosis in LC. The interaction of LC with intra-epidermal microorganisms (as, for instance, the Treponema pallidum) might be important in the development of the epidermotropic infiltration. This mainly consists of lymphocytes, which sometimes form a pseudolymphoma. A correlation between LC and granuloma formation is suggested.

Klinik, Diagnostik mid Therapie der Chromomykose

Zusammenfassung: Bei der Chromomykose handelt es sich um eine selten vorkommende, chronische, fast ausschlieBlich die Haut betreffende Infektion, hervorgerufen durch bestimmte dunkelpigmentierte Pilzarten.

Pityrosporum ovale/orbiculare in Papillomatous Nevus Cell Nevi

62% of 200 papillomatous nevus cell nevi compared to 45% of 40 seborrheic keratoses showed the presence of Pityrosporum ovale/orbiculare (Malassezia furfur) on their surface, supposedly representing a saprophytic state of the microorganisms in vivo. The papillomatous nevus cell nevi were of the compound or dermal type. Significant inflammation, dysplasia or major changes in color were absent. Electron microscopy revealed the characteristic, sometimes budding fungal cells. A relationship between the presence of Pityrosporum organisms and papillomatosis is discussed.

Die Dermatomykologie im geschichtlichen Überblick

Zusammenfassung. Diese Übersicht bezieht sich im ersten Abschnitt auf klinische Aspekte in der Geschichte der Dermatomykologie, im zweiten Teil kommt die Phase der Entdeckung der Pilze bei bestimmten Hauterkrankungen im 19. Jh. zur Sprache, was den Beginn der Dermatomykologie kennzeichnete. Es wird auf die Bedeutung der Interaktion von Pilzen und Wirtsorganismus in diesem Kontext hingewiesen und auch auf erste Untersuchungen, die zu dieser Thematik an Pflanzen am Ende des 17. Jahrhunderts von Marcello Malpighi durchgeführt wurden, aufmerksam gemacht.

Zur Morphologie der Malassezia-assoziierten Erkrankungen

Zusammenfassung. Die morphologischen Untersuchungen geben Auskunft über das Vorkommen, die Struktur und die Topik des Mikroorganismus Malassezia furfur an der Hautoberfläche und vermitteln Einblicke in die Begleiterscheinungen am Makroorganismus bei Pityriasis versicolor, Malassezia‐Follikulitis und seborrhoischem Ekzem. Aus morphologischer Sicht lassen sich die Malassezia‐assoziierten Dermatosen zwei unter‐schiedlichen Krankheitsgruppen zuordnen. Eine Gruppe ist von zahlreichen, im Stratum corneum adhärenten Mikroorganismen geprägt (Beispiel: Pityriasis versicolor); die andere Gruppe ist von einer Entzün‐dungsreaktion gekennzeichnet (Beispiel: seborrhoisches Ekzem), die Pilzzellen lassen sich hierbei in der Horn‐schicht mikromorphologisch im allgemeinen nicht nachweisen, sie können jedoch in den Foliikelostien wie an der gesunden Haut vorkommen.

Palmar Papillomatous Lesions Reminiscent of Epidermal Nevus in a Case of Focal Dermal Hypoplasia: A Nosological Consideration

A 40-year-old woman with focal dermal hypoplasia had a palmar papillomatous lesion showing a linear arrangement and histopathological features compatible with a diagnosis of epidermal nevus. This unusual manifestation of focal dermal hypoplasia is difficult to categorize. Undoubtedly the lesion reflects functional X-chromosome mosaicism. Although the mechanism of lyonization may give rise to true epidermal nevi such as CHILD nevus, we prefer to classify the present skin lesion as a nevoid disorder and not as an epidermal nevus.