A modified prosthesis head for middle ear titanium implants--experimental and first clinical results.

Objective: An ossicular chain defect represents a challenging situation for otosurgeons. Despite modern reconstruction techniques, unsatisfying postoperative hearing results regularly occur. These are commonly caused by prosthesis dislocation.

In vitro culturing of porcine tracheal mucosa as an ideal model for investigating the influence of drugs on human respiratory mucosa.

It has been previously shown that fresh mucosa from different mammals could serve as raw material for in vitro culturing with the differentiation of cilia, which are the most important morphological structures for the function of the mucociliary system. Increasing legal restrictions on the removal of human tissue and changing surgical techniques have led to a lack of fresh human mucosa for culturing. Most of the animals that have been used as donors up to now are genetically not very close to human beings and must all be sacrificed for such studies.

[The influence of different alpha-sympathomimetic drugs and benzalkoniumchlorid on the ciliary beat frequency of in vitro cultured human nasal mucosa cells].

Background: An appropriate in-vitro model of the human nasal mucosa was developed, which allowed to measure the influence of different pharmaceutical substances on the ciliary beat frequency (CBF) under standardized conditions.

Method: The present study describes the effect of the alpha-sympathomimetic drugs naphazolin, xylometazolin and oxymetazolin as pure substances and the preservative Benzalkonium chloride in rising concentrations on the CBF. For these investigations human cells of the human nasal mucosa were cultured, which exhibited a high constancy during the equilibration measurements over at least 200 minutes.

A new approach to pharmacological effects on ciliary beat frequency in cell cultures--exemplary measurements under Pelargonium sidoides extract (EPs 7630).

The ciliary beat frequency (CBF) is an important parameter of the defence mechanism of the mucociliary system. We present a new method to determine pharmacological effects on CBF in vitro. Ciliated cell cultures of human nasal epithelium were obtained from partial resection of hyperplastic inferior turbinates in rhinosurgery.

Ciliogenesis in submersion and suspension cultures of human nasal epithelial cells.

Human nasal respiratory cells lose cilia in submerged cultures. This study compares the effect of extracellular matrix (ECM) molecules of the basal lamina on ciliogenesis in submerged cell cultures to ECM-free suspension cultures. Respiratory mucosa of nasal turbinates was the routine source for the cultures of nasal epithelial cells.

[Using the Mongolian gerbil (Meriones unguiculatus) as an animal model in ontogenetic cochlear implant research].

One of the problems when providing prelingually deafened children with a cochlear implant is to find the optimal moment for the implantation in order to make optimal use of the sensitive phase in the maturation of the auditory system and to achieve the maximum improvement of hearing. Ontogenetic questions can be investigated in animal experiments under controlled conditions. In the present study an animal model (gerbil, Meriones unguiculatus) was established to simulate the situation of prelingually deafened children and to examine the influence of chronic electrostimulation on the development of the auditory pathway.

[Standardized measurement of sound transmission of different middle ear prostheses].

The sound transmission properties of three different commercially available middle ear implants and the prototype of a complete middle ear prosthesis (CoMEP) were evaluated with a special measurement system that permits standardized conditions. This system uses a mechanical middle ear model (MMM) which approximates the impedances of the tympanic membrane and inner ear. The implants were fitted under defined conditions into the MMM.

Standardized measurements of the sound transmission of middle ear implants using a mechanical middle ear model.

Several ways to evaluate the sound transmission properties of middle ear implants are now established. Besides computer-based simulations using acoustic and electrical analog circuits or finite element analysis, measurements can be performed with temporal bone preparations. Experiments with these preparations consider various anatomical properties, but a large number of parameters influence the outcome of measurements.

[Measuring vibration properties of middle ear implants with the mechanical middle ear model. Initial results].

With the aid of a mechanical middle ear model (MMM) the sound transmission properties of different middle ear implants were investigated. Input of the MMM involved a broad-band signal from 100 to 5000 Hz that was supplied by a miniaturized loudspeaker. Displacement of an artificial stapes footplate was measured by a fiberoptic probe.

[A registration system for evaluating acusto-mechanical transmission of middle ear implants].

A measurement system was developed that permits objective comparisons of the sound conduction of middle ear implants. The implants are fitted into a mechanical middle ear model which approximates the impedances of the eardrum and the inner ear. A defined signal within the frequency range of 0-5 kHz is provided by a miniaturized loudspeaker at the input to the model and is measured by a probe microphone.