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Biomedical subjects

A Schwinn

Publications and source records attributed to A Schwinn.

23 records · Page 2Linked to original sources

Phylogeny and dating of some pathogenic keratinophilic fungi using small subunit ribosomal RNA.

The phylogenetic relationship of representative members of the genera Trichophyton, Microsporum and Epidermophyton was studied. 844 base pairs were compared after sequencing the nuclear 18S ribosomal RNA gene spanning the most variable area within the central 600 bases of this gene. The dermatophytes, which are monophyletic in origin, could be classified most effectively when placed as a subgroup in the Onygenales, Ascomycotina. The calculated radiation time was about 50 million years ago. The early cenozoic adaptive explosion of mammals, which can serve as a host for the keratinophilic fungi, provides corroboration for proximate co-evolution.

Arthrodermataceae↗

Phaeohyphomycosis caused by Exophiala jeanselmei treated with itraconazole.

Phaeohyphomycotic cysts developed on the right knee of a 72-year-old woman undergoing immunosuppressive treatment for ulcerative colitis 6 years after accidental inoculation of soil in a bicycle accident. The lesions were red, firm, slightly raised, 0.5-1 cm in size and completely asymptomatic. The diagnosis was made by histopathological examination of three excised cysts and by repeated isolation of Exophiala jeanselmei in pure culture. The excised cyst walls contained large numbers of dematiaceous fungal elements in the form of hyphae, yeast-like cells and some cells dividing internally by a transverse septum. The patient was treated with 200 mg of itraconazole daily, but the treatment had to be stopped because of severe side-effects after 6 weeks. Histologically the cysts were cleared of dematiaceous elements, but E. jeanselmei could still be isolated from one of two skin biopsies 1 month after the end of therapy.

Aged↗

Frequency of Trichophyton rubrum in tinea capitis.

Trichophyton rubrum has led to unprecedented worldwide suppression of other dermatophytes which had been predominant earlier as a causative agent of superficial dermatomycoses. In tinea capitis on the other hand, several other species of Trichophyton or Microsporum are dominant depending on the region or continent. Tinea capitis caused by T. rubrum is a rare event worldwide. Occasional concentrations may be explained by several cases occurring by chance in one family or community. The relative frequency of this causative agent in tinea capitis in children is under 1%. In adults, however, where tinea capitis occurs very infrequently indeed, the incidence of T. rubrum appears to exceed 10%. Apart from two studies from India, one from Iran, two from Portugal and observations from Germany, which in the first country report of around 30% of all cases published, while the others document some 10% each, there are not only any conspicuous, unequivocal concentrations at all. Increased frequency of T. rubrum in this clinical picture has not been easily recognizable over the last decades due to low absolute case numbers.

Humans↗

Trichophyton rubrum as the causative agent of tinea capitis in three children.

Tinea capitis, which is caused by Trichophyton rubrum, is only rarely described in medical literature. Incidence of this disease appears to lie well below 1% in Europe. Microsporum canis, Trichophyton mentagrophytes and Trichophyton tonsurans are the predominant causative agents discussed here. In April 1993 T. rubrum was isolated from typical pathological changes to the capillitium area in three children from a Nigerian family, who had been living in Germany for 3 years. All three children revealed multiple, round or irregularly formed, partially infiltrated, partially pustular, hairless areas measuring up to 2 cm in diameter and covered with tightly clinging scales. The children's parents did not suffer from any dermatological complaints. The oldest child had had these pathological changes for about 5 months, the other two for a shorter length of time. Therapy with 10 mg kg(-1) body weight of griseofulvin led to rapid recovery over a period of 4 weeks.

Child, Preschool↗