TY - JOUR A1 - Voelker, Johannes A1 - Voelker, Christine A1 - Engert, Jonas A1 - Goemann, Nikolas A1 - Hagen, Rudolf A1 - Rak, Kristen T1 - Spontaneous Calcium Oscillations through Differentiation: A Calcium Imaging Analysis of Rat Cochlear Nucleus Neural Stem Cells JF - Cells N2 - Causal therapies for the auditory-pathway and inner-ear diseases are still not yet available for clinical application. Regenerative medicine approaches are discussed and examined as possible therapy options. Neural stem cells could play a role in the regeneration of the auditory pathway. In recent years, neural stem and progenitor cells have been identified in the cochlear nucleus, the second nucleus of the auditory pathway. The current investigation aimed to analyze cell maturation concerning cellular calcium activity. Cochlear nuclei from PND9 CD rats were microscopically dissected and propagated as neurospheres in free-floating cultures in stem-cell medium (Neurobasal, B27, GlutaMAX, EGF, bFGF). After 30 days, the dissociation and plating of these cells took place under withdrawal of the growth factors and the addition of retinoic acid, which induces neural cell differentiation. Calcium imaging analysis with BAPTA-1/Oregon Green was carried out at different times during the differentiation phase. In addition, the influence of different voltage-dependent calcium channels was analyzed through the targeted application of inhibitors of the L-, N-, R- and T-type calcium channels. For this purpose, comparative examinations were performed on CN NSCs, and primary CN neurons. As the cells differentiated, a significant increase in spontaneous neuronal calcium activity was demonstrated. In the differentiation stage, specific frequencies of the spontaneous calcium oscillations were measured in different regions of the individual cells. Initially, the highest frequency of spontaneous calcium oscillations was ascertainable in the maturing somata. Over time, these were overtaken by calcium oscillations in the axons and dendrites. Additionally, in the area of the growth cones, an increasing activity was determined. By inhibiting voltage-dependent calcium channels, their expression and function in the differentiation process were confirmed. A comparable pattern of maturation of these channels was found in CN NSCs and primary CN neurons. The present results show that neural stem cells of the rat cochlear nucleus differentiated not only morphologically but also functionally. Spontaneous calcium activities are of great relevance in terms of neurogenesis and integration into existing neuronal structures. These functional aspects of neurogenesis within the auditory pathway could serve as future targets for the exogenous control of neuronal regeneration. KW - neurogenesis KW - neural stem cells KW - neuronal oscillations KW - neuronal maturation KW - auditory pathway KW - regenerative capacity Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-248482 SN - 2073-4409 VL - 10 IS - 10 ER - TY - JOUR A1 - Taeger, Johannes A1 - Müller-Graff, Franz-Tassilo A1 - Neun, Tilmann A1 - Köping, Maria A1 - Schendzielorz, Philipp A1 - Hagen, Rudolf A1 - Rak, Kristen T1 - Highly precise navigation at the lateral skull base by the combination of flat-panel volume CT and electromagnetic navigation JF - Science Progress N2 - This study aimed to evaluate the feasibility and accuracy of electromagnetic navigation at the lateral skull base in combination with flat panel volume computed tomography (fpVCT) datasets. A mastoidectomy and a posterior tympanotomy were performed on 10 samples of fresh frozen temporal bones. For registration, four self-drilling titanium screws were applied as fiducial markers. Multi-slice computed tomography (MSCT; 600 µm), conventional flat panel volume computed tomography (fpVCT; 466 µm), micro-fpVCT (197 µm) and secondary reconstructed fpVCT (100 µM) scans were performed and data were loaded into the navigation system. The resulting fiducial registration error (FRE) was analysed, and control of the navigation accuracy was performed. The registration process was very quick and reliable with the screws as fiducials. Compared to using the MSCT data, the micro-fpVCT data led to significantly lower FRE values, whereas conventional fpVCT and secondary reconstructed fpVCT data had no advantage in terms of accuracy. For all imaging modalities, there was no relevant visual deviation when targeting defined anatomical points with a navigation probe. fpVCT data are very well suited for electromagnetic navigation at the lateral skull base. The use of titanium screws as fiducial markers turned out to be ideal for comparing different imaging methods. A further evaluation of this approach by a clinical trial is required. KW - electromagnetic navigation KW - fpVCT KW - fiducial registration error KW - lateral skull base KW - otology KW - cochlear implantation Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-250268 SN - 2047-7163 VL - 104 IS - 3 ER - TY - JOUR A1 - Taeger, Johannes A1 - Müller-Graff, Franz-Tassilo A1 - Lukas, Ilgen A1 - Schendzielorz, Philipp A1 - Hagen, Rudolf A1 - Neun, Tilman A1 - Rak, Kristen T1 - Cochlear duct length measurements in computed tomography and magnetic resonance imaging using newly developed techniques JF - OTO Open N2 - Objective Growing interest in measuring the cochlear duct length (CDL) has emerged, since it can influence the selection of cochlear implant electrodes. Currently the measurements are performed with ionized radiation imaging. Only a few studies have explored CDL measurements in magnetic resonance imaging (MRI). Therefore, the presented study aims to fill this gap by estimating CDL in MRI and comparing it with multislice computed tomography (CT). Study Design Retrospective data analyses of 42 cochleae. Setting Tertiary care medical center. Methods Diameter (A value) and width (B value) of the cochlea were measured in HOROS software. The CDL and the 2-turn length were determined by the elliptic circular approximation (ECA). In addition, the CDL, the 2-turn length, and the angular length were determined via HOROS software by the multiplanar reconstruction (MPR) method. Results CDL values were significantly shorter in MRI by MPR (d = 1.38 mm, P < .001) but not by ECA. Similar 2-turn length measurements were significantly lower in MRI by MPR (d = 1.67 mm) and ECA (d = 1.19 mm, both P < .001). In contrast, angular length was significantly higher in MRI (d = 26.79°, P < .001). When the values were set in relation to the frequencies of the cochlea, no clinically relevant differences were estimated (58 Hz at 28-mm CDL). Conclusion In the presented study, CDL was investigated in CT and MRI by using different approaches. Since no clinically relevant differences were found, diagnostics with radiation may be omitted prior to cochlear implantation; thus, a concept of radiation-free cochlear implantation could be established. KW - CDL KW - cochlear implantation KW - temporal bone KW - CT KW - MRI Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-263922 VL - 5 IS - 3 ER - TY - JOUR A1 - Radeloff, Katrin A1 - Weiss, Dorothee A1 - Hagen, Rudolf A1 - Kleinsasser, Norbert A1 - Radeloff, Andreas T1 - Differentiation behaviour of adipose-derived stromal cells (ASCs) seeded on polyurethane-fibrin scaffolds in vitro and in vivo JF - Biomedicines N2 - Adipose-derived stromal cells (ASCs) are a promising cell source for tissue engineering and regenerative medicine approaches for cartilage replacement. For chondrogenic differentiation, human (h)ASCs were seeded on three-dimensional polyurethane (PU) fibrin composites and induced with a chondrogenic differentiation medium containing TGF-ß3, BMP-6, and IGF-1 in various combinations. In addition, in vitro predifferentiated cell-seeded constructs were implanted into auricular cartilage defects of New Zealand White Rabbits for 4 and 12 weeks. Histological, immunohistochemical, and RT-PCR analyses were performed on the constructs maintained in vitro to determine extracellular matrix (ECM) deposition and expression of specific cartilage markers. Chondrogenic differentiated constructs showed a uniform distribution of cells and ECM proteins. RT-PCR showed increased gene expression of collagen II, collagen X, and aggrecan and nearly stable expression of SOX-9 and collagen I. Rabbit (r)ASC-seeded PU-fibrin composites implanted in ear cartilage defects of New Zealand White Rabbits showed deposition of ECM with structures resembling cartilage lacunae by Alcian blue staining. However, extracellular calcium deposition became detectable over the course of 12 weeks. RT-PCR showed evidence of endochondral ossification during the time course with the expression of specific marker genes (collagen X and RUNX-2). In conclusion, hASCs show chondrogenic differentiation capacity in vitro with the expression of specific marker genes and deposition of cartilage-specific ECM proteins. After implantation of predifferentiated rASC-seeded PU-fibrin scaffolds into a cartilage defect, the constructs undergo the route of endochondral ossification. KW - polyurethane KW - fibrin KW - ASC KW - adipose-derived stromal cells KW - chondrogenic differentiation KW - endochondral ossification KW - BMP-6 KW - TGF-ß3 Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-245030 SN - 2227-9059 VL - 9 IS - 8 ER - TY - JOUR A1 - Moratin, Helena A1 - Ickrath, Pascal A1 - Scherzad, Agmal A1 - Meyer, Till Jasper A1 - Naczenski, Sebastian A1 - Hagen, Rudolf A1 - Hackenberg, Stephan T1 - Investigation of the immune modulatory potential of zinc oxide nanoparticles in human lymphocytes JF - Nanomaterials N2 - Zinc oxide nanoparticles (ZnO-NP) are commonly used for a variety of applications in everyday life. In addition, due to its versatility, nanotechnology supports promising approaches in the medical sector. NP can act as drug-carriers in the context of targeted chemo- or immunotherapy, and might also exhibit autonomous immune-modulatory characteristics. Knowledge of potential immunosuppressive or stimulating effects of NP is indispensable for the safety of consumers as well as patients. In this study, primary human peripheral blood lymphocytes of 9 donors were treated with different sub-cytotoxic concentrations of ZnO-NP for the duration of 1, 2, or 3 days. Flow cytometry was performed to investigate changes in the activation profile and the proportion of T cell subpopulations. ZnO-NP applied in this study did not induce any significant alterations in the examined markers, indicating their lack of impairment in terms of immune modulation. However, physicochemical characteristics exert a major influence on NP-associated bioactivity. To allow a precise simulation of the complex molecular processes of immune modulation, a physiological model including the different components of an immune response is needed. KW - zinc oxide nanoparticles KW - immunomodulation KW - T cell subpopulations Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-234016 SN - 2079-4991 VL - 11 IS - 3 ER - TY - JOUR A1 - Meyer, Till Jasper A1 - Stöth, Manuel A1 - Moratin, Helena A1 - Ickrath, Pascal A1 - Herrmann, Marietta A1 - Kleinsasser, Norbert A1 - Hagen, Rudolf A1 - Hackenberg, Stephan A1 - Scherzad, Agmal T1 - Cultivation of head and neck squamous cell carcinoma cells with wound fluid leads to cisplatin resistance via epithelial-mesenchymal transition induction JF - International Journal of Molecular Sciences N2 - Locoregional recurrence is a major reason for therapy failure after surgical resection of head and neck squamous cell carcinoma (HNSCC). The physiological process of postoperative wound healing could potentially support the proliferation of remaining tumor cells. The aim of this study was to evaluate the influence of wound fluid (WF) on the cell cycle distribution and a potential induction of epithelial-mesenchymal transition (EMT). To verify this hypothesis, we incubated FaDu and HLaC78 cells with postoperative WF from patients after neck dissection. Cell viability in dependence of WF concentration and cisplatin was measured by flow cytometry. Cell cycle analysis was performed by flow cytometry and EMT-marker expression by rtPCR. WF showed high concentrations of interleukin (IL)-6, IL-8, IL-10, CCL2, MCP-1, EGF, angiogenin, and leptin. The cultivation of tumor cells with WF resulted in a significant increase in cell proliferation without affecting the cell cycle. In addition, there was a significant enhancement of the mesenchymal markers Snail 2 and vimentin, while the expression of the epithelial marker E-cadherin was significantly decreased. After cisplatin treatment, tumor cells incubated with WF showed a significantly higher resistance compared with the control group. The effect of cisplatin-resistance was dependent on the WF concentration. In summary, proinflammatory cytokines are predominantly found in WF. Furthermore, the results suggest that EMT can be induced by WF, which could be a possible mechanism for cisplatin resistance. KW - cell proliferation KW - wound fluid KW - epithelial-mesenchymal transition KW - cisplatin resistance KW - Interleukin KW - head and neck squamous cell carcinoma Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-258722 SN - 1422-0067 VL - 22 IS - 9 ER - TY - JOUR A1 - Meyer, Till Jasper A1 - Gerhard-Hartmann, Elena A1 - Lodes, Nina A1 - Scherzad, Agmal A1 - Hagen, Rudolf A1 - Steinke, Maria A1 - Hackenberg, Stephan T1 - Pilot study on the value of Raman spectroscopy in the entity assignment of salivary gland tumors JF - PLoS One N2 - Background The entity assignment of salivary gland tumors (SGT) based on histomorphology can be challenging. Raman spectroscopy has been applied to analyze differences in the molecular composition of tissues. The aim of this study was to evaluate the suitability of RS for entity assignment in SGT. Methods Raman data were collected in deparaffinized sections of pleomorphic adenomas (PA) and adenoid cystic carcinomas (ACC). Multivariate data and chemometric analysis were completed using the Unscrambler software. Results The Raman spectra detected in ACC samples were mostly assigned to nucleic acids, lipids, and amides. In a principal component-based linear discriminant analysis (LDA) 18 of 20 tumor samples were classified correctly. Conclusion In this proof of concept study, we show that a reliable SGT diagnosis based on LDA algorithm appears possible, despite variations in the entity-specific mean spectra. However, a standardized workflow for tissue sample preparation, measurement setup, and chemometric algorithms is essential to get reliable results. KW - Head and neck cancers KW - salivary gland tumors KW - salivary glands KW - cancers and neoplasms KW - malignant tumors KW - lipids KW - raman spectroscopy KW - surgical oncology Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-264736 VL - 16 IS - 9 ER - TY - JOUR A1 - Kurz, Anja A1 - Zanzinger, Maren A1 - Hagen, Rudolf A1 - Rak, Kirsten T1 - The impact of cochlear implant microphone settings on the binaural hearing of experienced cochlear implant users with single sided deafness JF - European Archives of Oto-Rhino-Laryngology N2 - Objective Cochlear implantation has become a well-accepted treatment option for people with single-sided deafness (SSD) and has become a clinical standard in many countries. A cochlear implant (CI) is the only device which restores binaural hearing. The effect of microphone directionality (MD) settings has been investigated in other CI indication groups, but its impact on speech perception in noise has not been established in CI users with SSD. The focus of this investigation was, therefore, to assess binaural hearing effects using different MD settings in CI users with SSD. Methods Twenty-nine experienced CI users with SSD were recruited to determine speech reception thresholds with varying target and noise sources to define binaural effects (head shadow, squelch, summation, and spatial release from masking), sound localization, and sound quality using the SSQ12 and HISQUI19 questionnaires. Outcome measures included the MD settings “natural”, “adaptive”, and “omnidirectional”. Results The 29 participants involved in the study were divided into two groups: 11 SONNET users and 18 OPUS 2/RONDO users. In both groups, a significant head shadow effect of 7.4–9.2 dB was achieved with the CI. The MD setting “adaptive” provided a significant head shadow effect of 9.2 dB, a squelch effect of 0.9 dB, and spatial release from masking of 7.6 dB in the SONNET group. No significant summation effect could be determined in either group with CI. Outcomes with the omnidirectional setting were not significantly different between groups. For both groups, localization improved significantly when the CI was activated and was best when the omnidirectional setting was used. The groups’ sound quality scores did not significantly differ. Conclusions Adaptive directional microphone settings improve speech perception and binaural hearing abilities in CI users with SSD. Binaural effect measures are valuable to quantify the benefit of CI use, especially in this indication group. KW - single-sided deafness KW - cochlear implant KW - adaptive directional microphone setting KW - questionnaire Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-231750 SN - 0937-4477 ET - corrected version ER - TY - JOUR A1 - Ickrath, Pascal A1 - Sprügel, Lisa A1 - Beyersdorf, Niklas A1 - Scherzad, Agmal A1 - Hagen, Rudolf A1 - Hackenberg, Stephan T1 - Detection of Candida albicans-Specific CD4+ and CD8+ T Cells in the Blood and Nasal Mucosa of Patients with Chronic Rhinosinusitis JF - Journal of Fungi N2 - Candida albicans is ubiquitously present, and colonization in the nose and oral cavity is common. In healthy patients, it usually does not act as a pathogen, but in some cases can cause diseases. The influence of C. albicans as a trigger of T cell activation on the pathogenesis of chronic rhinosinusitis (CRS) is controversial, and its exact role is not clear to date. The aim of the present study was to detect and characterize C. albicans-specific CD4+ and CD8+ T cells in patients with CRS, with and without nasal polyps. Tissue and blood samples were collected from patients suffering from chronic rhinosinusitis with (CRSwNP) and without nasal polyps (CRSsNP), and from healthy controls. A peptide pool derived from C. albicans antigen was added to tissue and blood samples. After 6 days, lymphocytes were analyzed by multicolor flow cytometry. Activation was assessed by the intracellular marker Ki-67, and the cytokine secretion was measured. Tissue CD8+ T cells of CRSsNP patients showed a significantly higher proportion of Ki-67+ cells after activation with C. albicans antigen compared to peripheral blood CD8+ T cells. Cytokine secretion in response to C. albicans antigen was similar for all study groups. In this study, C. albicans-specific CD4+ and CD8+ T cells were detected in peripheral blood and mucosal tissue in all study groups. In patients suffering from CRSsNP, C. albicans-specific CD8+ T cells were relatively enriched in the nasal mucosa, suggesting that they might play a role in the pathogenesis of CRSsNP. KW - Candida albicans KW - chronic rhinosinusitis KW - T cell activation KW - nasal polyps Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-239671 SN - 2309-608X VL - 7 IS - 6 ER - TY - JOUR A1 - Gehrke, Thomas A1 - Hackenberg, Stephan A1 - Tecle, Nyat A1 - Hagen, Rudolf A1 - Scherzad, Agmal T1 - Tuberculosis in the Head and Neck: Changing Trends and Age-Related Patterns JF - The Laryngoscope N2 - Objective To evaluate changing trends in patient collectives, age-related patterns of manifestation, and diagnostic pathways of patients with extrapulmonary head and neck tuberculosis (TB), and to provide strategies to fasten diagnosis in these patients. Study design Case control study. Methods A 10-year retrospective analysis of 35 patients diagnosed with extrapulmonary TB in the head and neck at a tertiary university institution from 2009 to 2019, with special focus on the influence of the patient's age on consideration of TB and clinical patterns. Results The vast majority of patients younger than 40 years had their origin in countries with high TB burden (P = .0003), and TB was considered very early as a differential diagnosis (P = .0068), while most patients older than 40 years were domestic citizens initially suspected for a malignancy, who more often had an underlying immunosuppressive condition (0.0472). Most frequent manifestations in both groups were the lymph nodes, larynx, and oropharynx. Surprisingly, no differences in the rates of open TB or history of TB infection in the family anamnesis were found. Conclusion The two groups of patients found most often are younger patients migrating from regions with high TB burden and elderly domestic patients suffering from immunosuppressive conditions, with the latter often being misdiagnosed as malignancies. TB remains an important but difficult differential diagnosis, due to the initially unspecific symptoms and the great variety in the presentation of manifestations in the head and neck. KW - lymph node tuberculosis KW - Tuberculosis KW - head and neck KW - extrapulmonary tuberculosis KW - laryngeal tuberculosis Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-257524 VL - 131 IS - 12 ER - TY - JOUR A1 - Engert, Jonas A1 - Rak, Kristen A1 - Bieniussa, Linsa A1 - Scholl, Miriam A1 - Hagen, Rudolf A1 - Völker, Johannes T1 - Evaluation of the Neurogenic Potential in the Rat Inferior Colliculus from Early Postnatal Days Until Adulthood JF - Molecular Neurobiology N2 - Neural stem cells (NSCs) have been recently identified in the inferior colliculus (IC). These cells are of particular interest, as no casual therapeutic options for impaired neural structures exist. This research project aims to evaluate the neurogenic potential in the rat IC from early postnatal days until adulthood. The IC of rats from postnatal day 6 up to 48 was examined by neurosphere assays and histological sections. In free-floating IC cell cultures, neurospheres formed from animals from early postnatal to adulthood. The amount of generated neurospheres decreased in older ages and increased with the number of cell line passages. Cells in the neurospheres and the histological sections stained positively with NSC markers (Doublecortin, Sox-2, Musashi-1, Nestin, and Atoh1). Dissociated single cells from the neurospheres differentiated and were stained positively for the neural lineage markers β-III-tubulin, glial fibrillary acidic protein, and myelin basic protein. In addition, NSC markers (Doublecortin, Sox-2, CDK5R1, and Ascl-1) were investigated by qRT-PCR. In conclusion, a neurogenic potential in the rat IC was detected and evaluated from early postnatal days until adulthood. The identification of NSCs in the rat IC and their age-specific characteristics contribute to a better understanding of the development and the plasticity of the auditory pathway and might be activated for therapeutic use. KW - central auditory pathway KW - inferior colliculus KW - neural progenitor cells KW - neural stem cells KW - neurosphere Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-235811 SN - 0893-7648 VL - 58 ER -