[Optimized fitting of a midface implant to anchor a magnetic nasal prosthesis using 3D printing].

Background: Plate-based anchorage systems for craniofacial prostheses offer advantages over extraoral solitary titanium implants in terms of the flexible choice of mounting points and higher stability. Disadvantages become apparent in the complex individual intraoperative adaptation of the plate-based systems to the usually poorly accessible bone. The current article presents a method to overcome these disadvantages and make greater use of the advantages of plate-based systems.

Access to the Apical Cochlear Modiolus for Possible Stem Cell-based and Gene Therapy of the Auditory Nerve.

Objective: Loss of spiral ganglion neurons (SGN) is permanent and responsible for a substantial number of patients suffering from hearing impairment. It can derive from the degeneration of SGNs due to the death of sensory hair cells as well as from auditory neuropathy. Utilizing stem cells to recover lost SGNs increasingly emerges as a possible therapeutic option, but access to human SGNs is difficult due to their protected location within the bony impacted cochlea.

Mastoid cavity obliteration and Vibrant Soundbridge implantation for patients with mixed hearing loss.

Objectives/hypothesis: To review the results of obliteration of a preexisting mastoid cavity with abdominal fat and Vibrant Soundbridge implantation in patients with mixed hearing loss (MHL) and to compare the data with results of Vibrant Soundbridge implantation in patients with MHL without mastoid cavity and with pure sensorineural hearing loss (SNHL).

Study Design: Retrospective chart analysis of 10 patients (10 ears) with MHL and preexisting mastoid cavity, 18 patients (19 ears) with MHL alone and nine patients (10 ears) with SNHL treated in one tertiary referral center.

Methods: Vibrant Soundbridge implantation and obliteration in case a mastoid cavity existed previously.

Structure and function of cochlear afferent innervation.

Purpose Of Review: For the perception of sound, acoustic signals need to be encoded into a neuronal code. This takes place at the inner hair cells of the organ of Corti and the afferent fibres of the auditory nerve. We will review the current knowledge of the anatomy and function of these elements as well as their connection - formed by the afferent inner hair cell synapse.

The Ca2+ channel subunit beta2 regulates Ca2+ channel abundance and function in inner hair cells and is required for hearing.

Hearing relies on Ca(2+) influx-triggered exocytosis in cochlear inner hair cells (IHCs). Here we studied the role of the Ca(2+) channel subunit Ca(V)beta(2) in hearing. Of the Ca(V)beta(1-4) mRNAs, IHCs predominantly contained Ca(V)beta(2).

Tuning of synapse number, structure and function in the cochlea.

Cochlear inner hair cells (IHCs) transmit acoustic information to spiral ganglion neurons through ribbon synapses. Here we have used morphological and physiological techniques to ask whether synaptic mechanisms differ along the tonotopic axis and within IHCs in the mouse cochlea. We show that the number of ribbon synapses per IHC peaks where the cochlea is most sensitive to sound.

Ca2+-binding proteins tune Ca2+-feedback to Cav1.3 channels in mouse auditory hair cells.

Sound coding at the auditory inner hair cell synapse requires graded changes in neurotransmitter release, triggered by sustained activation of presynaptic Ca(v)1.3 voltage-gated Ca(2+) channels. Central to their role in this regard, Ca(v)1.

A gain-of-function mutation in synaptotagmin-1 reveals a critical role of Ca2+-dependent soluble N-ethylmaleimide-sensitive factor attachment protein receptor complex binding in synaptic exocytosis.

Synaptotagmin-1, the Ca2+ sensor for fast neurotransmitter release, was proposed to function by Ca2+-dependent phospholipid binding and/or by Ca2+-dependent soluble N-ethylmaleimide-sensitive factor attachment protein receptor (SNARE) complex binding. Extensive in vivo data support the first hypothesis, but testing the second hypothesis has been difficult because no synaptotagmin-1 mutation is known that selectively interferes with SNARE complex binding. Using knock-in mice that carry aspartate-to-asparagine substitutions in a Ca2+-binding site of synaptotagmin-1 (the D232N or D238N substitutions), we now show that the D232N mutation dramatically increases Ca2+-dependent SNARE complex binding by native synaptotagmin-1, but leaves phospholipid binding unchanged.

Functional inactivation of a fraction of excitatory synapses in mice deficient for the active zone protein bassoon.

Mutant mice lacking the central region of the presynaptic active zone protein Bassoon were generated to establish the role of this protein in the assembly and function of active zones as sites of synaptic vesicle docking and fusion. Our data show that the loss of Bassoon causes a reduction in normal synaptic transmission, which can be attributed to the inactivation of a significant fraction of glutamatergic synapses. At these synapses, vesicles are clustered and docked in normal numbers but are unable to fuse.

Structure/function analysis of Ca2+ binding to the C2A domain of synaptotagmin 1.

Synaptotagmin 1, a Ca2+ sensor for fast synaptic vesicle exocytosis, contains two C2 domains that form Ca2+-dependent complexes with phospholipids. To examine the functional importance of Ca2+ binding to the C2A domain of synaptotagmin 1, we studied two C2A domain mutations, D232N and D238N, using recombinant proteins and knock-in mice. Both mutations severely decreased intrinsic Ca2+ binding and Ca2+-dependent phospholipid binding by the isolated C2A domain.