An increased number of patients with residual hearing are undergoing cochlear implantation. A subset of these experience delayed hearing loss post-implantation, and the aetiology of this loss is not well understood. Our previous studies suggest that electrical stimulation can induce damage to hair cells in organ of Corti (OC) organotypic cultures.
View Article and Find Full Text PDFAnnu Int Conf IEEE Eng Med Biol Soc
July 2019
New regulations for medical products complicate research projects for new application fields and translation of innovative product ideas to refundable medical products becomes a high economic risk. All this demands for a CE-marked platform, which offers the possibility to access the recorded data online or even directly the hardware during research applications, to bridge the gap. This paper describes how a CE-marked medical product can be extended by different interfaces to enable basic research or simplify first proof-of-concept studies thus optimizing prototype development in research projects, simplifying the documentation process and reducing the risk for market access.
View Article and Find Full Text PDFThe first multiplication sign (.) for unit μC cm¯·phase¯ was not placed, which is part of the author's correction. Furthermore, the unit appears anywhere in the article.
View Article and Find Full Text PDFIncreasing numbers of cochlear implant patients have residual hearing. Despite surgical and pharmacological efforts to preserve residual hearing, a significant number of these patients suffer a late, unexplained loss of residual hearing. Surgical trauma can be excluded as the cause.
View Article and Find Full Text PDFPatients scheduled for cochlear implantation often retain residual hearing in the low frequencies. Unfortunately, some patients lose their residual hearing following implantation and the reasons for this are not well understood. Evidence suggests that electrotoxicity could be one of the factors responsible for this late adverse effect.
View Article and Find Full Text PDFMany aspects of stress-induced physiological and psychological effects have been characterized in people and animals. However, stress effects on the auditory system are less explored and their mechanisms are not well-understood, in spite of its relevance for a variety of diseases, including tinnitus. To expedite further research of stress-induced changes in the auditory system, here we compare the reactions to stress among Wistar and Lewis rats.
View Article and Find Full Text PDFTreatment of partial hearing loss with the combined electrical and acoustical stimulation (EAS) aims at restoring the hearing while preserving the residual hearing. The aim of present study was to establish an in vitro system to study the effects of an electrical field on the auditory hair cells and spiral ganglion cells. Cochlear tissues containing the organ of Corti, spiral limbus and spiral ganglion neurons were dissected from post-natal Wistar rats (p3-p5) and cultured in the micro-channels.
View Article and Find Full Text PDFCochlea implants (CI) restore the hearing in patients with sensorineural hearing loss by electrical stimulation of the auditory nerve via an electrode array. The increase of the impedance at the electrode-tissue interface due to a postoperative connective tissue encapsulation leads to higher power consumption of the implants. Therefore, reduced adhesion and proliferation of connective tissue cells around the CI electrode array is of great clinical interest.
View Article and Find Full Text PDFHypothesis: Ultra high viscous (UHV-) alginate is a suitable matrix for brain-derived neurotrophic factor (BDNF) producing cells, enabling cell survival and BDNF release out of the matrix and subsequent protection of auditory neuronal cells.
Background: Cochlear implant (CI) target cells, spiral ganglion cells (SGC), undergo a progressive degeneration. BDNF prevents SGC from degeneration but has to be delivered locally to the inner ear for months.
One goal in biomaterials research is to limit the formation of connective tissue around the implant. Antiwetting surfaces are known to reduce ability of cells to adhere. Such surfaces can be achieved by special surface structures (lotus effect).
View Article and Find Full Text PDFThe treatment of choice for profound sensorineural hearing loss (SNHL) is direct electrical stimulation of spiral ganglion cells (SGC) via a cochlear implant (CI). The number and excitability of SGC seem to be critical for the success that can be achieved via CI treatment. However, SNHL is associated with degeneration of SGC.
View Article and Find Full Text PDFJ Biomed Mater Res B Appl Biomater
May 2012
For best hearing sensation, electrodes of auditory prosthesis must have an optimal electrical contact to the respective neuronal cells. To improve the electrode-nerve interface, microstructuring of implant surfaces could guide neuronal cells toward the electrode contact. To this end, femtosecond laser ablation was used to generate linear microgrooves on the two currently relevant cochlear implant materials, silicone elastomer and platinum.
View Article and Find Full Text PDFPurpose: To evaluate the optical and anatomical effects of oral propranolol treatment for infantile periocular capillary haemangioma.
Methods: All children diagnosed with infantile capillary haemangioma in 2008-2010 at a tertiary paediatric medical centre underwent comprehensive evaluation, including imaging, by a multidisciplinary team followed by oral propranolol treatment. Clinical follow-up was performed regularly until the lesions disappeared.
The hearing performance with conventional hearing aids and cochlear implants is dramatically reduced in noisy environments and for sounds more complex than speech (e. g. music), partially due to the lack of localized sensorineural activation across different frequency regions with these devices.
View Article and Find Full Text PDFCyclophosphamide, methotrexate and 5-fluorouracile (CMF)-based chemotherapy for adjuvant treatment of breast cancer reduces the risk of relapse. In this exploratory study, we tested the feasibility of identifying molecular markers of recurrence in CMF-treated patients. Using Affymetrix U133A GeneChips, RNA samples from 19 patients with primary breast cancer who had been uniformly treated with adjuvant CMF chemotherapy were analyzed.
View Article and Find Full Text PDFJ Biomed Mater Res B Appl Biomater
October 2008
Cochlear implants (CIs) can restore hearing in deaf patients by electrical stimulation of the auditory nerve. To optimize the electrical stimulation, the number of independent channels must be increased by reduction of connective tissue growth on the electrode surface and selective neuronal cell contact. The femtosecond laser microstructuring of the electrode surfaces was performed to investigate the effect of fibroblast growth on the implant material.
View Article and Find Full Text PDFHypothesis: Chronic implantation and electric stimulation with a human prototype auditory midbrain implant (AMI) array within the inferior colliculus achieves minimal neuronal damage and does not cause any severe complications.
Background: An AMI array has been developed for patients with neural deafness and, based on animal studies, has shown to possess potential as an auditory prosthesis in humans. To investigate the safety of the AMI for clinical use, we characterized the histomorphologic effects of chronic implantation and stimulation within its target structure, the inferior colliculus.
In order to evaluate risk assessment instruments for sex offenders in Germany, we compared the predictive validity of the Static-99, HCR-20, SVR-20, and PCL-R scales for 134 sex offenders. The mean follow-up time was 9 years (range 1-340 months), using the first entry into the National Register of Criminal Convictions as endpoint variable. For the estimate of predictive power, the area under the curve (AUC) of receiver operating characteristic (ROC) analysis was calculated.
View Article and Find Full Text PDFExpression of eight tumour-relevant genes was studied in formalin-fixed, paraffin-embedded tissue from 54 invasive ductal breast carcinomas using quantitative reverse transcription PCR (Q-RT-PCR). Seven of the genes map to chromosome 20q and are potential candidates for gene amplification and over-expression. The Her2/neu oncogene, on chromosome 17q, was investigated in the same tumours.
View Article and Find Full Text PDFTumor cells in abdominal lavage specimens from patients with gastric carcinoma strongly predict subsequent peritoneal metastasis and poor prognosis. Reverse transcription (RT)-polymerase chain reaction (PCR) detection of wild-type E-cadherin has been claimed to be superior to conventional cytology for the detection of patients who subsequently develop peritoneal metastases. The present study tested this hypothesis and determined whether or not the detection of mutated, tumor-specific E-cadherin messenger RNA in abdominal lavage specimens serve as a useful diagnostic tool.
View Article and Find Full Text PDFA major function of the cell-to-cell adhesion molecule E-cadherin is the maintenance of cell adhesion and tissue integrity. E-cadherin deficiency in tumours leads to changes in cell morphology and motility, so that E-cadherin is considered to be a suppressor of invasion. In this study we investigated the functional consequences of three tumour-associated gene mutations that affect the extracellular portion of E-cadherin: in-frame deletions of exons 8 or 9 and a point mutation in exon 8, as they were found in human gastric carcinomas.
View Article and Find Full Text PDFRhabdomyosarcomas bear a morphological and genetic resemblance to developing skeletal muscle. Apart from myogenic marker genes (bHLH factors, myosin, actin), cell adhesion molecules such as N-cadherin and N-CAM have been reported to be expressed both in rhabdomyosarcomas and during myogenesis. The present study demonstrates the expression of another cadherin, cadherin-11, in rhabdomyosarcomas and during differentiation of myoblasts in vitro: cadherin-11, a predominantly mesenchymal cell adhesion molecule, is highly expressed in embryonal rhabdomyosarcomas and alveolar rhabdomyosarcomas, which do not bear the Pax-3-FKHR fusion previously described.
View Article and Find Full Text PDFThe cell adhesion molecule E-cadherin (CDH1; MIM# 192090) has been implicated in numerous cellular functions, ranging from controlling morphogenesis to suppressing tumor invasion. We describe 11 previously unreported somatic E-cadherin mutations in two subgroups of gastric and breast cancer showing markedly reduced homophilic cell-to-cell interactions. Using reverse transcription-polymerase chain reaction (RT-PCR) and direct sequencing of the entire coding region 5 mutations were detected in diffuse-type gastric cancer specimens.
View Article and Find Full Text PDFThe frequency and prognostic relevance of sarcoid-like lesions and microcarcinosis in regional lymph nodes in gastric cancer (n = 113; pT1-3, pN0-1, pM0, R0) were investigated; the prognostic value was compared with pT and pN stage, grading and Laurén's tumor classification with Cox's multivariate regression-model. Sarcoid like lesions were found in 34% of the cases (n = 113). Statistical analysis did not indicate that they had any prognostic value or showed whether or not microcarcinosis or metastasis was present; they were independent of pT stage, histological tumor type, tumor grading, and the clinical course of disease.
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