No abstract

Sensorineural hearing loss is a common sequela of acute and chronic otitis media, and the round window membrane (RWM) is currently being considered as a major route for noxious agents to pass from the middle ear cavity to the cochlea. Streptococcus pneumoniae, a major causative agent of otitis media, and Streptococcus pyogenes A produce molecularly related toxins, pneumolysin and streptolysin O (SLO), that form large pores in target membranes. In this study, we analyzed the effects of SLO on the permeability of the RWM. Resected RWMs from a total of 104 guinea pigs were embedded between two chambers of an in vitro system. One chamber was designated as the tympanal (cis) compartment, and the other was designated as the inner ear (trans) compartment. The permeability of normal and SLO-damaged RWMs towards Na ؉ , [ 14 C]mannitol, and proteins was investigated. SLO evoked permeability defects dose dependently in the RWM with fluxes of both Na ؉ and [ 14 C]mannitol being demonstrable over a time span of up to 8 h. Serum proteins and radioiodinated SLO were also shown to pass through the damaged RWM. Scanning electron microscopy revealed the morphological correlates to these results. We propose that damage to the RWM by potent pore-forming cytolysins leads to leakage of ions from the perilymph. Ionic disequilibrium and passage of noxious macromolecules to the cochlea could contribute to disturbances of the inner ear function.

Aims: We established a real-time PCR assay for the detection and strain identification of Candida species and demonstrated the ability to differentiate between Candida albicans the most common species, and also Candida parapsilosis, Candida glabrata, Candida tropicalis and Candida dubliniensis by LightCycler PCR and melting curve analysis. Methods and Results: The DNA isolation from cultures and serum was established using the QIAmp Tissue Kit. The sensitivity of the assay was >/= 2 genome equivalents/assay. It was possible to differentiate all investigated Candida species by melting curve analysis, and no cross-reaction to human DNA or Aspergillus species could be observed. Conclusions: The established real-time PCR assay is a useful tool for the rapid identification of Candida species and a base technology for more complex PCR assays. Significance and Impact of the Study: We carried out initial steps in validation of a PCR assay for the detection and differentiation of medically relevant Candida species. The PCR was improved by generating PCR standards, additional generation of melting curves for species identification and the possibility to investigate different specimens simultaneously

The diagnostic performance of single-serum assays for toxoplasma-specific immunoglobulin (Ig)M. IgA. IgG, and IgE antibodies and of different combinations of such antibody assays in 20 European reference centers was assessed. A panel of 276 sera, of which 73 came from patients who seroconverted within 3 months (acute infection), 49 from patients who had seroconverted 3-12 months earlier (convalescence), and 154 from subjects who had two IgG-positive samples obtained 12 months apart (past infection), was tested with 20 toxoplasma-antibody assays and 195 combinations. In general, every assay with high diagnostic sensitivity showed low diagnostic specificity, i.e. no assay performed alone could reliably distinguish acute from past infection. Furthermore, no single assay (or combination) could separate convalescence from the other stages of toxoplasma infection. However, excellent diagnostic performances were reached by sequential use of highly sensitive IgM assays and methods examining IgG avidity or stage specificity. IgA or IgM assays were less suitable for confirmation of toxoplasma-IgM positivity. This study documents the strength of test combinations in assessing the stage of toxoplasma infection.

The data show that moxifloxacin was as efficacious as imipenem in reducing the mortality rate of mice suffering from a severe systemic aerobic/anaerobic infection.

The passage of radioiodinated streptolysin-O (SLO) and albumin through the round window membrane (RWM) was studied in vivo. When applied to the middle ear, SLO became quantitatively entrapped in this compartment and no passage to the cochlea occurred. However, flux of radioiodinated albumin through the toxin-damaged RWM was observed. We propose that the passage of noxious macromolecules, such as proteases, from a purulent middle-ear effusion may be facilitated by pore-forming toxins, resulting in cochlear damage and sensorineural hearing loss.

We present laboratory data from 22 patients suspected of having neurosyphilis. In two cases the suspicion could not be confirmed, and in 20 cases neurosyphilis was detected. The sera from 17 patients were also assayed for Borrelia-specific antibodies. Suspicious immunoglobulin G antibody indices were detected in nine cases and a suspicious immunoglobulin M antibody index in one. In six of these, stored CSF/serum pairs were available to specify the antibodies by immunoblotting. This allowed for the identification of one patient apparently infected by both Borrelia spp. and Treponema pallidum. In all cases of newly suspected neurosyphilis, we recommend considering neuroborreliosis at the same time.

In order to investigate the accuracy and practicability of the polymerase chain reaction (PCR) in the antenatal diagnosis of congenital toxoplasmosis, a collaborative study involving 15 European laboratories was performed under the auspices of the Biomed 2 Programme of the European Community. Each team received 12 aliquots (four negative, eight positive) of 'artificial samples' made of amniotic fluid spiked with tachyzoites of the RH strain of Toxoplasma gondii. Each team performed its own PCR protocol (all were different). Nine of the 15 laboratories were able to detect a single parasite, but two of the 15 found all samples negative. Four of the 15 laboratories found one or more control samples to be falsely positive. This study highlights the lack of homogeneity between PCR protocols and performance and underlines the need for an external quality assurance scheme which could provide 'reference' samples that could be used by any laboratory wanting to establish and maintain an accurate diagnostic test based on PCR.