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Biomedical subjects

H P Zenner

Publications and source records attributed to H P Zenner.

At least 37 records · Page 2Linked to original sources
PubMed2001

Open Tübingen titanium prostheses for ossiculoplasty: a prospective clinical trial.

OBJECTIVE: The overall purpose of the study was the evaluation of the efficacy of Tübingen titanium prostheses (TTPs) for ossiculoplasty. STUDY DESIGN: A two-part clinical study of 216 patients undergoing ossiculoplasty was performed. The first part was a prospective study using TTPs (n = 114). The second part involved study of historical control patients (n = 102) with gold and ceramic prostheses. INTERVENTIONS: All patients underwent ossiculoplasty. MAIN OUTCOME MEASURES: Measures included median air conduction thresholds and air-bone gaps. RESULTS: All patients were per-protocol patients. When the air-bone gap "gold standard" (i.e., < or =10 dB) was investigated in the main speech spectrum, partial TTPs reached this level at 2 kHz in 44% (n = 22) and at 3 kHz in 38% (n = 19). Gold and ceramics revealed significantly lower values. Similar results were obtained for total prostheses. Differences for TTPs and ceramics were statistically significant (Mann-Whitney U test, alpha = 5%). CONCLUSION: The use of TTPs for ossiculoplasty is an efficient treatment method.

Acoustic Stimulation↗
PubMed2001

Total implantation of the active hearing implant TICA for middle ear disease: a temporal bone study.

A subpopulation of hearing-impaired patients has conductive hearing loss that cannot be improved by classic tympanoplasty. Other patients have a mixed hearing loss and cannot be helped by present forms of ear surgery or by hearing aids. Possible help for some patients may come from current implantable hearing devices if these are modified for the patient's specific anatomic situation. The TICA LZ 3001 is a hearing implant for total implantation used to treat moderate to severe sensorineural hearing loss. Most patients who use it have a normal ossicular chain that allows coupling of the implant to the incus. The present temporal bone study demonstrates that the TICA can also be used in patients with an interrupted ossicular chain. If the incus long process shows a defect, the TICA may be coupled to the incus body, and connection between the stapes and the long process of the incus can be achieved with a commercially available titanium-angle prosthesis or liquid ionomeric cement. In cases of an absent incus, the coupling axis of the transducer may be coupled to the stapes head via a modified coupling element. With an absent stapes, the coupling axis may be coupled directly to the perilymph by a coupling element similar to a gold stapes prosthesis.

Ear, Middle↗
PubMed2001

[An attempt to identify the most frequent genomic mutations responsible for isolated deafness in patients after cochlear implantation].

The aim of this study was to identify subjects with 35delG mutation of GJB2 gene as the most frequent genetic cause of deafness. Deaf patients receiving cochlear implantation at the ENT Clinic at University of Medical Sciences in Poznań and their family members were recruited to the study. Peripheral blood lymphocytes DNA was amplified in allele-specific PCR and analysed for single strand conformation polymorphism (SSCP) to detect mutation at DFNB1 locus. 35delG mutation at both alleles was found at 42.9% of deaf patients and 29.4% of health relatives were found to be carrier of the mutation at one allele. The study is thought to be a first step in analysis of typical mutations in Polish deaf population.

Adolescent↗
PubMed2001

Frequency of the recessive 30delG mutation in the GJB2 gene in Northeast-Hungarian individuals and patients with hearing impairment.

Mutations in the GJB2 gene, which encodes a gap junction protein (connexin 26) account for up to 50% of cases of congenital autosomal recessive non-syndromic hearing impairment. A single mutation, 30delG, is responsible for 70% of this autosomal recessive hearing loss in Europe. This study describes the 30delG mutation analysis of 23 Hungarian families (64 individuals) with at least two subjects with congenital non-syndromic hearing defect and of 52 unrelated individuals from the Northeastern population of Hungary. In all patients, non-progressive hearing impairment varied from moderate to profound involving all frequencies. DNA was tested by PCR based restriction enzyme assay (BSiYI). Sixty-four percent of the patients displayed this one base deletion in GJB2. Out of these, 65.9% were homozygous for this mutation and 34.1% were heterozygotes. The latter showed compound heterozygosity since in these 14 patients, eight previously reported different nucleotide changes were observed on the second allele. The carrier frequency of the 30delG mutation among control group was one in 10.4 (9.6%). This high frequency of 30delG corresponds more to frequencies reported in Southern than in North Europeans.

Adolescent↗
PubMed2000

[Telemedicine in otorhinolaryngology. Basic principles and possible applications].

Telemedicine includes all medical activities involved in diagnosis, therapeutics or social medicine undertaken by an electronic transfer medium. This technique requires the transmission of visual and acoustic information over long distances and does not require the specialist to be personally present at the requested consultation. In the last few years, the digital data transmission, e.g., ISDN (ISDN (Integrated Service Digital Network), has become available and has facilitated the use of telecommunication. Recently, the real-time transmission of acoustic and visual signals will be improved by use of asynchronous transfer mode (ATM). Advanced telecommunication applications in minimally invasive ENT surgery are experimental in most cases. We can distinguish three different telesurgical developments: surgical teleconsultation, surgical teleassistance, and surgical telemanipulation. The different applications and transmission media are explained and discussed.

Forecasting↗
PubMed2000

[Mutational analysis of the connexin26 gene in sporadic cases of moderate to profound deafness].

Non-syndromic neurosensory recessive deafness (NSRD) is one of the most common human sensory disorders. Mutations in the connexin 26 gene have been established as a major cause of inherited and sporadic non-syndromic deafness in different populations. The CX26 gene encodes the gap junction protein connexin 26 (beta-2, GJB2), whose expression was shown in several tissues and in the cochlea. The 30delG mutation is the most frequent mutation in the CX26 gene. It represents a deletion of guanosine (G) in a sequence of six Gs extending from position 30 to 35 of the CX26 cDNA. The deletion creates a frameshift resulting in a premature stop codon and a non-functional intracellular domain in the protein. The 30delG mutation can be detected at the molecular level using PCR followed by BsiYI digestion. We screened 164 mainly German patients with non-syndromic sporadic deafness for this mutation to determine its distribution in the German population. The frequency of the mutation in our analyzed patients was lower than in other studies and therefore indicates its dependency on geographically distinct populations.

Audiometry, Pure-Tone↗
PubMed2000

[Telemedicine in otorhinolaryngology exemplified by a Tübingen-Leipzig video conference].

"Telemedicine" is a major new development with great potential for improving health care delivery. It therefore affects each department in medicine. There is a great deal of telemedicine activity around the world. However, the term telemedicine is not clear. It describes all forms of medical information, transferred from a relevant distance by an electronic transfer media. An essential condition for communication is the intelligibility between transmitter and receiver. Because of different transmitting technologies and networks in distinct countries, towns, or even academic institutions, satisfactory contact is not possible. In the last decade, the demand for worldwide audiovisual data transmission has led to the standardization of telecommunication media. Therefore it is no longer necessary to transport medical data (or even patients) by conventional manners, e.g., post, car, or aircraft. Telemedicine for diagnosis and management can be bidirectional in real-time, long-distance videoconferencing, in which the patient consults a specialist located at the remote site, or it can be the transmission of either real-time or pre-recorded images and data to a remote expert, as in teleradiology or telepathology. Another application is the use of videoconference systems in the course of meetings. The remote specialist has the opportunity to take part in the session, e.g., with a lecture. Furthermore, the remote specialist can demonstrate special operative techniques for teleteaching purposes, some of which may be specialities of the particular medical unit, e.g., operation in open NMR, telemanipulation, or telerobotic procedures. In this paper, we describe the use and benefit of a videoconference between the departments of otolaryngology and head and neck surgery of the Universities of Tübingen and Leipzig by means of an "ISDN-based videoconference system". During the meeting, the "operating course for reconstructive surgery in the head and neck", the practicability, reliability, costs and quality were determined and compared with other technologies for audiovisual data transfer.

Curriculum↗
PubMed2000

[Audiovisual telecommunication by multimedia technology in HNO medicine. ISDN--internet--ATM].

Telemedicine includes all medical activities in diagnosis, therapeutics, or social medicine undertaken by means of an electronic transfer medium, enabling the transmission of visual and acoustic information over long distances to doctors not personally present at the place of the requested consultation. Most experience with telemedicine applications has been gained in the field of diagnosis (teleconsultation, teleradiology, telepathology) and is expanding to quality control and quality assurance. Decisive for each form of application is its availability, practicability, cost, safety, and especially quality of audiovisual transmission. For telesurgical applications, particularly the use of minimally invasive techniques in otorhinolaryngology, head, and neck surgery, the high quality transmission of audiovisual data in real time is necessary. Rapid expansion and further developments in transmission technologies and networks in the last decade have created several technologies with increased quality and costs. In this paper, we tested different transmission media for audiovisual telecommunication--integrated services digital network (ISDN), Internet, and asynchronous transfer mode (ATM)--using real time video transmission of typical operations in otorhinolaryngology. Their applications, costs, and future perspectives are discussed.

Germany↗
PubMed2000

In vivo experiments in the cat with an implantable piezoelectric hearing aid transducer.

We have recently developed an implantable piezoelectric hearing aid transducer that is suitable for implantation in patients with sensorineural hearing loss. The transducer does not transmit sound but conducts micromechanical vibrations to the cochlea. In ten cat ears we investigated the efficiency of the implantable transducer with respect to the direct transfer of vibrations within the audible frequency range via the ossicles to the cochlea or directly into the vestibule. The acoustically evoked brainstem potential (ABR) threshold was determined prior to implantation, and the middle ear was then opened and the piezoelectric transducer coupled to the ossicles or to the perilymph. Acoustically evoked brainstem potentials were recorded following stimulation at the umbo, long process of the incus, stapes head, stapes foot plate, and in the vestibulum. Comparisons of the acoustically and mechanically evoked thresholds revealed a good correlation of the two stimulation levels. An electrical transducer voltage of 1 V(RMS) produced equivalent sound pressure levels (SPL) of 100-128 dB at the tympanic membrane. To assess the hearing we compared stimulus-dependent latencies of the early potentials (peaks P1-P5) and thresholds. This evaluation was based on four ears with normal hearing in which the piezoelectric transducer was coupled to the long process of the incus. The mean values of the latencies and their scattering range correlated extremely well in the two stimulation modes. They were nearly identical when the equivalent SPL of 100 dB was assigned to the maximally applied electrical level of 0 dB. These in vitro and in vivo findings demonstrate that the characteristics of the transducer warrant its development further from the prototype stage to become a component of an implantable hearing device for patients with sensorineural hearing loss.

Acoustic Stimulation↗
PubMed2000

Three-dimensional motion of the organ of Corti.

The vibration of the organ of Corti, a three-dimensional micromechanical structure that incorporates the sensory cells of the hearing organ, was measured in three mutually orthogonal directions. This was achieved by coupling the light of a laser Doppler vibrometer into the side arm of an epifluorescence microscope to measure velocity along the optical axis of the microscope, called the transversal direction. Displacements were measured in the plane orthogonal to the transverse direction with a differential photodiode mounted on the microscope in the focal plane. Vibration responses were measured in the fourth turn of a temporal-bone preparation of the guinea-pig cochlea. Responses were corrected for a "fast" wave component caused by the presence of the hole in the cochlear wall, made to view the structures. The frequency responses of the basilar membrane and the reticular lamina were similar, with little phase differences between the vibration components. Their motion was rectilinear and vertical to the surface of their membranes. The organ of Corti rotated about a point near the edge of the inner limbus. A second vibration mode was detected in the motion of the tectorial membrane. This vibration mode was directed parallel to the reticular lamina and became apparent for frequencies above approximately 0.5 oct below the characteristic frequency. This radial vibration mode presumably controls the shearing action of the hair bundles of the outer hair cells.

Animals↗