@article{NoyaletIlgenBuerkleinetal.2022, author = {Noyalet, Laurent and Ilgen, Lukas and B{\"u}rklein, Miriam and Shehata-Dieler, Wafaa and Taeger, Johannes and Hagen, Rudolf and Neun, Tilmann and Zabler, Simon and Althoff, Daniel and Rak, Kristen}, title = {Vestibular aqueduct morphology and Meniere's disease - development of the vestibular aqueduct score by 3D analysis}, series = {Frontiers in Surgery}, volume = {9}, journal = {Frontiers in Surgery}, issn = {2296-875X}, doi = {10.3389/fsurg.2022.747517}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-312893}, year = {2022}, abstract = {Improved radiological examinations with newly developed 3D models may increase understanding of Meniere's disease (MD). The morphology and course of the vestibular aqueduct (VA) in the temporal bone might be related to the severity of MD. The presented study explored, if the VA of MD and non-MD patients can be grouped relative to its angle to the semicircular canals (SCC) and length using a 3D model. Scans of temporal bone specimens (TBS) were performed using micro-CT and micro flat panel volume computed tomography (mfpVCT). Furthermore, scans were carried out in patients and TBS by computed tomography (CT). The angle between the VA and the three SCC, as well as the length of the VA were measured. From these data, a 3D model was constructed to develop the vestibular aqueduct score (VAS). Using different imaging modalities it was demonstrated that angle measurements of the VA are reliable and can be effectively used for detailed diagnostic investigation. To test the clinical relevance, the VAS was applied on MD and on non-MD patients. Length and angle values from MD patients differed from non-MD patients. In MD patients, significantly higher numbers of VAs could be assigned to a distinct group of the VAS. In addition, it was tested, whether the outcome of a treatment option for MD can be correlated to the VAS.}, language = {en} } @article{GehrkeHackenbergTecleetal.2021, author = {Gehrke, Thomas and Hackenberg, Stephan and Tecle, Nyat and Hagen, Rudolf and Scherzad, Agmal}, title = {Tuberculosis in the Head and Neck: Changing Trends and Age-Related Patterns}, series = {The Laryngoscope}, volume = {131}, journal = {The Laryngoscope}, number = {12}, doi = {10.1002/lary.29668}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-257524}, pages = {2701-2705}, year = {2021}, abstract = {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.}, language = {en} } @article{RadeloffRadeloffRamosTiradoetal.2020, author = {Radeloff, Katrin and Radeloff, Andreas and Ramos Tirado, Mario and Scherzad, Agmal and Hagen, Rudolf and Kleinsasser, Norbert H. and Hackenberg, Stephan}, title = {Toxicity and functional impairment in human adipose tissue-derived stromal cells (hASCs) following long-term exposure to very small iron oxide particles (VSOPs)}, series = {Nanomaterials}, volume = {10}, journal = {Nanomaterials}, number = {4}, issn = {2079-4991}, doi = {10.3390/nano10040741}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-203676}, year = {2020}, abstract = {Magnetic nanoparticles (NPs), such as very small iron oxide NPs (VSOPs) can be used for targeted drug delivery, cancer treatment or tissue engineering. Another important field of application is the labelling of mesenchymal stem cells to allow in vivo tracking and visualization of transplanted cells using magnetic resonance imaging (MRI). For these NPs, however, various toxic effects, as well as functional impairment of the exposed cells, are described. The present study evaluates the influence of VSOPs on the multilineage differentiation ability and cytokine secretion of human adipose tissue derived stromal cells (hASCs) after long-term exposure. Human ASCs were labelled with VSOPs, and the efficacy of the labelling was documented over 4 weeks in vitro cultivation of the labelled cells. Unlabelled hASCs served as negative controls. Four weeks after labelling, adipogenic and osteogenic differentiation was histologically evaluated and quantified by polymerase chain reaction (PCR). Changes in gene expression of IL-6, IL-8, VEGF and caspase 3 were determined over 4 weeks. Four weeks after the labelling procedure, labelled and unlabelled hASCs did not differ in the gene expression of IL-6, IL-8, VEGF and caspase 3. Furthermore, the labelling procedure had no influence on the multidifferentiation ability of hASC. The percentage of labelled cells decreased during in vitro expansion over 4 weeks. Labelling with VSOPs and long-term intracellular disposition probably have no influence on the physiological functions of hASCs. This could be important for the future in vivo use of iron oxide NPs.}, language = {en} } @article{IckrathWagnerScherzadetal.2017, author = {Ickrath, Pascal and Wagner, Martin and Scherzad, Agmal and Gehrke, Thomas and Burghartz, Marc and Hagen, Rudolf and Radeloff, Katrin and Kleinsasser, Norbert and Hackenberg, Stephan}, title = {Time-Dependent Toxic and Genotoxic Effects of Zinc Oxide Nanoparticles after Long-Term and Repetitive Exposure to Human Mesenchymal Stem Cells}, series = {International Journal of Environmental Research and Public Health}, volume = {14}, journal = {International Journal of Environmental Research and Public Health}, number = {12}, doi = {10.3390/ijerph14121590}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-169932}, pages = {1590}, year = {2017}, abstract = {Zinc oxide nanoparticles (ZnO-NP) are widely spread in consumer products. Data about the toxicological characteristics of ZnO-NP is still under controversial discussion. The human skin is the most important organ concerning ZnO-NP exposure. Intact skin was demonstrated to be a sufficient barrier against NPs; however, defect skin may allow NP contact to proliferating cells. Within these cells, stem cells are the most important toxicological target for NPs. The aim of this study was to evaluate the genotoxic and cytotoxic effects of ZnO-NP at low-dose concentrations after long-term and repetitive exposure to human mesenchymal stem cells (hMSC). Cytotoxic effects of ZnO-NP were measured by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assay. Furthermore, genotoxicity was evaluated by the comet assay. For long-term observation over 6 weeks, transmission electron microscopy (TEM) was applied. The results of the study indicated cytotoxic effects of ZnO-NP beginning at high concentrations of 50 μg/mL and genotoxic effects in hMSC exposed to 1 and 10 μg/mL ZnO-NP. Repetitive exposure enhanced cyto- but not genotoxicity. Intracellular NP accumulation was observed up to 6 weeks. The results suggest cytotoxic and genotoxic potential of ZnO-NP. Even low doses of ZnO-NP may induce toxic effects as a result of repetitive exposure and long-term cellular accumulation. This data should be considered before using ZnO-NP on damaged skin.}, language = {en} } @article{MeyerScherzadMoratinetal.2019, author = {Meyer, Till Jasper and Scherzad, Agmal and Moratin, Helena and Gehrke, Thomas Eckert and Killisperger, Julian and Hagen, Rudolf and Wohlleben, Gisela and Polat, B{\"u}lent and Dembski, Sofia and Kleinsasser, Norbert and Hackenberg, Stephan}, title = {The radiosensitizing effect of zinc oxide nanoparticles in sub-cytotoxic dosing is associated with oxidative stress in vitro}, series = {Materials}, volume = {12}, journal = {Materials}, number = {24}, issn = {1996-1944}, doi = {10.3390/ma12244062}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-193897}, pages = {4062}, year = {2019}, abstract = {Radioresistance is an important cause of head and neck cancer therapy failure. Zinc oxide nanoparticles (ZnO-NP) mediate tumor-selective toxic effects. The aim of this study was to evaluate the potential for radiosensitization of ZnO-NP. The dose-dependent cytotoxicity of ZnO-NP\(_{20 nm}\) and ZnO-NP\(_{100 nm}\) was investigated in FaDu and primary fibroblasts (FB) by an MTT assay. The clonogenic survival assay was used to evaluate the effects of ZnO-NP alone and in combination with irradiation on FB and FaDu. A formamidopyrimidine-DNA glycosylase (FPG)-modified single-cell microgel electrophoresis (comet) assay was applied to detect oxidative DNA damage in FB as a function of ZnO-NP and irradiation exposure. A significantly increased cytotoxicity after FaDu exposure to ZnO-NP\(_{20 nm}\) or ZnO-NP\(_{100 nm}\) was observed in a concentration of 10 µg/mL or 1 µg/mL respectively in 30 µg/mL of ZnO-NP\(_{20 nm}\) or 20 µg/mL of ZnO-NP\(_{100 nm}\) in FB. The addition of 1, 5, or 10 µg/mL ZnO-NP\(_{20 nm}\) or ZnO-NP\(_{100 nm}\) significantly reduced the clonogenic survival of FaDu after irradiation. The sub-cytotoxic dosage of ZnO-NP\(_{100 nm}\) increased the oxidative DNA damage compared to the irradiated control. This effect was not significant for ZnO-NP\(_{20 nm}\). ZnO-NP showed radiosensitizing properties in the sub-cytotoxic dosage. At least for the ZnO-NP\(_{100 nm}\), an increased level of oxidative stress is a possible mechanism of the radiosensitizing effect.}, language = {en} } @article{StefanakisBasslerWalczuchetal.2023, author = {Stefanakis, Mona and Bassler, Miriam C. and Walczuch, Tobias R. and Gerhard-Hartmann, Elena and Youssef, Almoatazbellah and Scherzad, Agmal and St{\"o}th, Manuel Bernd and Ostertag, Edwin and Hagen, Rudolf and Steinke, Maria R. and Hackenberg, Stephan and Brecht, Marc and Meyer, Till Jasper}, title = {The impact of tissue preparation on salivary gland tumors investigated by Fourier-transform infrared microspectroscopy}, series = {Journal of Clinical Medicine}, volume = {12}, journal = {Journal of Clinical Medicine}, number = {2}, issn = {2077-0383}, doi = {10.3390/jcm12020569}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-304887}, year = {2023}, abstract = {Due to the wide variety of benign and malignant salivary gland tumors, classification and malignant behavior determination based on histomorphological criteria can be difficult and sometimes impossible. Spectroscopical procedures can acquire molecular biological information without destroying the tissue within the measurement processes. Since several tissue preparation procedures exist, our study investigated the impact of these preparations on the chemical composition of healthy and tumorous salivary gland tissue by Fourier-transform infrared (FTIR) microspectroscopy. Sequential tissue cross-sections were prepared from native, formalin-fixed and formalin-fixed paraffin-embedded (FFPE) tissue and analyzed. The FFPE cross-sections were dewaxed and remeasured. By using principal component analysis (PCA) combined with a discriminant analysis (DA), robust models for the distinction of sample preparations were built individually for each parotid tissue type. As a result, the PCA-DA model evaluation showed a high similarity between native and formalin-fixed tissues based on their chemical composition. Thus, formalin-fixed tissues are highly representative of the native samples and facilitate a transfer from scientific laboratory analysis into the clinical routine due to their robust nature. Furthermore, the dewaxing of the cross-sections entails the loss of molecular information. Our study successfully demonstrated how FTIR microspectroscopy can be used as a powerful tool within existing clinical workflows.}, language = {en} } @article{KurzZanzingerHagenetal.2021, author = {Kurz, Anja and Zanzinger, Maren and Hagen, Rudolf and Rak, Kirsten}, title = {The impact of cochlear implant microphone settings on the binaural hearing of experienced cochlear implant users with single sided deafness}, series = {European Archives of Oto-Rhino-Laryngology}, journal = {European Archives of Oto-Rhino-Laryngology}, edition = {corrected version}, issn = {0937-4477}, doi = {10.1007/s00405-020-06450-5}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-231750}, year = {2021}, abstract = {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.}, language = {en} } @article{HackenbergMeyerHaefneretal.2022, author = {Hackenberg, Stephan and Meyer, Till Jasper and H{\"a}fner, Johannes and Scheich, Matthias and St{\"o}th, Manuel and Al-Tinawi, Fadi and Neun, Tilmann and Mlynski, Robert and Hagen, Rudolf and Scherzad, Agmal}, title = {Surgical management of tympanojugular paragangliomas using the flexible CO\(_2\) laser}, series = {European Archives of Oto-Rhino-Laryngology}, volume = {279}, journal = {European Archives of Oto-Rhino-Laryngology}, number = {12}, doi = {10.1007/s00405-022-07416-5}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-324164}, pages = {5623-5630}, year = {2022}, abstract = {Purpose Surgery is a standard therapy for tympanojugular paragangliomas (TJP). Maintaining the quality of life (QoL) requires functional preservation. The flexible CO\(_2\) laser allows contact-free tumor removal. This retrospective study compares the postoperative functional outcomes of TJP surgery with and without the flexible CO\(_2\) laser. Methods Between 2005 and 2019, 51 patients with TJP were surgically treated at a tertiary hospital. Until 2012, 17 patients received conventional surgery. Thereafter, the flexible laser was used in 34 patients. Tumor extend, pre- and postoperative cranial nerve function, and complications were compared between the groups. Results The cohort consisted of 33 class A and B tumors and 18 class C and D tumors. Preoperative embolization was performed in 17 cases. Class C/D TJP were usually removed via an infratemporal fossa type A approach. Gross total tumor removal was achieved in 14/18 class C/D tumors. 3/51 patients suffered from long-term partial or complete facial palsy. No differences in post-therapeutic cranial nerve function or complications were noted between the conventional and laser group. One recurrence was observed after complete tumor resection. Conclusion The flexible CO\(_2\) laser was shown to be a safe and effective alternative to conventional bipolar cauterization, which is appreciated by the surgeon in these highly vascularized tumors. Both techniques allowed a high tumor control rate and good long-term results also from a functional point of view.}, language = {en} } @article{TecleHackenbergScheichetal.2023, author = {Tecle, Nyat-Eyob and Hackenberg, Stephan and Scheich, Matthias and Scherzad, Agmal and Hagen, Rudolf and Gehrke, Thomas}, title = {Surgical management of lateral neck abscesses in children: a retrospective analysis of 100 cases}, series = {European Journal of Pediatrics}, volume = {182}, journal = {European Journal of Pediatrics}, number = {1}, doi = {10.1007/s00431-022-04676-5}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-324179}, pages = {431-438}, year = {2023}, abstract = {Cervical abscesses are relatively common infections in pediatric patients. There is an ongoing debate about the necessity and time point of surgical drainage. The identification of a focus of infection might play an important role in facilitating a therapeutic decision. In a retrospective study, 100 pediatric patients aged 1-18 years who underwent incision and drainage of a lateral cervical abscess at our institution were analyzed. Patients were divided into two groups based on whether a focus of infection could be identified or not. Data collection included patient characteristics, microbiological results, antibiotic regimen, and clinical course. A focus of infection was found in 29\% (29/100) of the patients, most frequently in the tonsils. A causative microorganism was found in 75\% (75/100) of all patients, with Staphylococcus aureus and Streptococcus pyogenes being the most common pathogens. All patients received an empiric antibiotic therapy in addition to surgery. Antibiotic medication was changed in 31\% in both groups (9/29 with a focus of infection and 22/71 without a focus of infection) during therapy. Children without an identified focus of infection generally were younger and had more comorbidities reducing immune response while also showing differences in the pathogens involved. There were no complications associated to surgery or antibiotic therapy in any of the patients involved. Conclusion: Children with an identified focus of infection show several differences compared to those with isolated lateral abscesses, especially regarding the microorganisms involved. But the focus of infection seems not to have an impact on patient's outcome. What is Known: • Neck abscesses are a relatively common disease in the pediatric population and may cause serious complications. • Therapy in general consists of intravenous antibiotics with or without surgery. What is New: • The focus identification has no impact on patient's outcome. • Children with an identified focus of infection show several differences compared to those with isolated lateral abscesses, especially regarding their medical history, age, and the microorganisms involved.}, language = {en} } @article{VoelkerVoelkerEngertetal.2021, author = {Voelker, Johannes and Voelker, Christine and Engert, Jonas and Goemann, Nikolas and Hagen, Rudolf and Rak, Kristen}, title = {Spontaneous Calcium Oscillations through Differentiation: A Calcium Imaging Analysis of Rat Cochlear Nucleus Neural Stem Cells}, series = {Cells}, volume = {10}, journal = {Cells}, number = {10}, issn = {2073-4409}, doi = {10.3390/cells10102802}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-248482}, year = {2021}, abstract = {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.}, language = {en} }