Cochlea implantation in patients with superficial hemosiderosis

Introduction!#!Superficial hemosiderosis is a sub-form of hemosiderosis in which the deposits of hemosiderin in the central nervous system damage the nerve cells. This form of siderosis is caused by chronic cerebral hemorrhages, especially subarachnoid hemorrhages. The diversity of symptoms depends on the respective damage to the brain, but in most of the cases it shows up as incipient unilateral or bilateral hearing loss, ataxia and signs of pyramidal tracts. We are investigating the question of whether cochlear implantation is a treatment option for patients with superficial hemosiderosis and which strategy of diagnostic procedure has to be ruled out preoperatively.!##!Materials and methods!#!In a tertiary hospital between 2009 and 2018, we examined (N = 5) patients with radiologically confirmed central hemosiderosis who suffered from profound hearing loss to deafness were treated with a cochlear implant (CI). We compared pre- and postoperative speech comprehension (Freiburg speech intelligibility test for monosyllables and HSM sentence test).!##!Results!#!Speech understanding improved on average by 20% (monosyllabic test in the Freiburg speech intelligibility test) and by 40% in noise (HSM sentence test) compared to preoperative speech understanding with optimized hearing aids.!##!Discussion!#!The results show that patients with superficial siderosis benefit from CI with better speech understanding. The results are below the average for all postlingual deaf CI patients. Superficial siderosis causes neural damages, which explains the reduced speech understanding based on central hearing loss. It is important to correctly weigh the patient's expectations preoperatively and to include neurologists within the therapy procedure

Characterisation of antibiotic moenomycin A interaction with phospholipid model membranes

Using a combination of physico-chemical techniques (MAS NMR, DSC, freeze-fracture electron microscopy, molecular modelling) the antibiotic moenomycin A was found to be anchored by its hydrophobic chain into multilamellar POPC membranes. The lamellar phase structure of the modified membrane is retained, while moenomycin A in water at different concentrations does not form any other but isotropic phase structures. The mobility of POPC molecule segments is reduced with increasing moenomycin A concentrations. Freeze-fracture electron microscopy images show ripple like structures for low moenomycin A concentrations, which are rare for high concentrations. A sugar-group network of the antibiotic seems to cover the whole membrane surface for molar ratios moenomycin A/POPC of 1:2, which is supported by C-13-MAS (Magic Angle Spinning) NMR, P-31-NMR, and molecular modelling. (C) 1997 Elsevier Science Ireland Ltd.status: publishe