Dermatophytes can trigger cooperative (CAMP-like) haemolytic reactions.

BACKGROUND: Dermatophytes usually grow on skin that is also colonized by bacteria. Therefore, a possible interaction between dermatophytes and bacteria is of potential relevance for the pathogenesis of skin infections. Cell membranes contribute substantially to epidermal barrier function. Erythrocyte haemolysis is a model commonly used to study membrane-damaging effects of microbial factors. Cooperative (CAMP-like) haemolytic reactions are known from distinct bacteria, but not from dermatophytes and bacteria. OBJECTIVES: To investigate CAMP-like reactions of dermatophytes. METHODS: Species of dermatophytes representing the genera Microsporum, Trichophyton and Epidermophyton, erythrocytes from sheep, horse and cattle, cultures of Staphylococcus aureus, S. intermedius, Listeria ivanovii, S. hyicus and S. epidermidis, and cell-free supernatants of bacterial cultures were used to search for cooperative haemolytic effects in in vitro agar diffusion assays. RESULTS: A cooperative (CAMP-like) haemolytic reaction was identified for all dermatophytes tested. Using erythrocytes from sheep and cattle, pretreated with a sphingomyelinase from S. aureus, S. intermedius or L. ivanovii, the fungi induced a distinct zone of complete haemolysis on solid media and in a diffusion test. No CAMP reaction could be detected using S. hyicus or S. epidermidis as a first-step agent or with equine erythrocytes. The lytic reaction of the CAMP-cohaemolysin derived from dermatophytes was always separate from the zone of complete haemolysis, indicating two different cytolytic factors. CONCLUSIONS: Our results show, for the first time, that in principle a CAMP-like effect can occur with dermatophtyes. This is a new observation of potential relevance for the pathogenesis of skin infections. The membrane-damaging factors released by dermatophytes should be further analysed.

Haemolytic activities of Trichophyton species.

Dermatophytes are keratinophilic fungi able to invade the stratum corneum of the skin and other keratinized structures. The pathogenic interactions between host and fungus are poorly understood. Some enzymes, especially keratinases, have previously been taken into consideration as virulence factors. Haemolysins have not been evaluated in this regard, though they are known to play an important role in the host-parasite interaction in bacterial infections. We investigate the haemolytic activity of four Trichophyton species: T. rubrum, T. mentagrophytes complex, Tequinum and T. verrucosum. The strains were tested on Columbia agar with 5% blood from horses, cattle and sheep. They show different haemolytic activities. T. rubrum and T. equinum produce a zone of complete haemolysis followed by a small zone of incomplete haemolysis around the colony. T. mentagrophytes and T. verrucosum produce a zone of complete haemolysis. Haemolytic activity is pronounced in dermatophytes and may play an important role as a virulence factor.

The RNA binding protein HuD: rat cDNA and analysis of the alternative spliced mRNA in neuronal differentiating cell lines P19 and PC12.

HuD belongs to a family of neurospecific RNA binding proteins found in man, frog and fly [49]. To investigate whether this protein is involved in regulation of neuronal differentiation of rodent cells in vivo and in vitro, the cDNA of the rat homolog gene (r-HuD) was cloned, its expression was studied in rat brain and in neurogenic cell lines, and the splicing of its RNA was analyzed. Coding sequences of HuD from man and rat were found to be 99.5 and 95% identical at protein and DNA level, respectively. In rat brain r-HuD transcripts 3.7 and 4.2 kb in length were detected by Northern blot analysis. RT-PCR and in situ hybridization revealed that rodent homologues of HuD transcripts are present in P19 mouse embryo carcinoma and in PC12 rat pheochromocytoma cell lines both able to differentiate into neurons. In contrast, r-HuD transcripts were not detectable in the rat glioma cell line C6. In P19 cells a strong induction of HuD mRNA was observed after triggering neuronal differentiation by retinoic acid, whereas in PC12 cells the mRNA was present before and after nerve growth factor (NGF) induced neuronal differentiation. In both neuronal cell lines and in brain of adult rat and mouse HuD mRNA is alternatively spliced in a region which encodes a proline rich linker domain between the second and third RNA recognition motif. This RNA processing event seems to be differently regulated in PC12 cells on the one hand, and in P19 cells and brain of rat and mouse on the other.

High-resolution 1H NMR spectroscopy of cerebrospinal fluid in spinal diseases.

Twenty-nine patients with disk herniations, 7 patients with intraspinal tumors, 4 patients with multiple sclerosis and one patient with infection by borrelia have been studied by CT, myelography and/or MR. To gain information on the metabolism of central nervous system disease (CNS), and thus, to improve diagnosis the cerebrospinal fluid (CSF) was studied in all cases using high-resolution 1H NMR spectroscopy at 360 MHz. Seventeen metabolites could be identified in CSF in addition to the usual clinical chemical parameters. As compared to a control group discrimination of tumors from inflammation was possible by means of different metabolites and/or metabolite concentration. The CSF in disk herniations differed in the concentration of acetate from the control group. In CSF of tumors, multiple sclerosis and of infection by borrelia distinct differences in the concentrations of putrescine, citrate, valine, alpha-alanine, acetate, creatinine, glucose, beta-hydroxy-butyric acid, glutamine and creatine have been observed both as compared directly and in comparison to the control group. Thus, high-resolution 1H NMR spectroscopy of CSF gives speedy information on metabolism, since a variety of metabolites, usually examined only in different tests, can be studied in one single step. Thus, high-resolution 1H NMR spectroscopy supports imaging, especially MR, as morphological changes in diseases may be differentiated by means of different metabolite profiles. This assumption needs further confirmation on a prospective study with a larger patient population.

Cerebellar ataxia with recovery related to central pontine myelinolysis.

Development of severe ataxia and mild pyramidal signs without mental deterioration, tetraparesis or pseudobulbar palsy during recovery from withdrawal delirium and initial hyponatraemia are unusual clinical features consistent with central pontine myelinolysis. This diagnosis was confirmed by magnetic resonance imaging (MRI) in an alcoholic man. Clinical and electrodiagnostic improvement occurred, whereas the MRI findings remained unchanged in a follow-up study.