Methods and reference data for middle ear transfer functions.

Human temporal bone specimens are used in experiments measuring the sound transfer of the middle ear, which is the standard method used in the development of active and passive middle ear implants. Statistical analyses of these experiments usually require that the TB samples are representative of the population of non-pathological middle ears. Specifically, this means that the specimens must be mechanically well-characterized. We present an in-depth statistical analysis of 478 data sets of middle ear transfer functions (METFs) from different laboratories. The data sets are preprocessed and various contributions to the variance of the data are evaluated. We then derive a statistical range as a reference against which individual METF measurements may be validated. The range is calculated as the two-sided 95% tolerance interval at audiological frequencies. In addition, the mean and 95% confidence interval of the mean are given as references for assessing the validity of a sample group. Finally, we provide a suggested procedure for measuring METFs using the methods described herein.

Biocompatibility and degradation of the open-pored magnesium scaffolds LAE442 and La2.

Porous magnesium implants are of particular interest for application as resorbable bone substitutes, due to their mechanical strength and a Young's modulus similar to bone. The objective of the present study was to compare the biocompatibility, bone and tissue ingrowth, and the degradation behaviour of scaffolds made from the magnesium alloys LAE442 (n= 40) and Mg-La2 (n= 40)in vivo. For this purpose, cylindrical magnesium scaffolds (diameter 4 mm, length 5 mm) with defined, interconnecting pores were produced by investment casting and coated with MgF2. The scaffolds were inserted into the cancellous part of the greater trochanter ossis femoris of rabbits. After implantation periods of 6, 12, 24 and 36 weeks, the bone-scaffold compounds were evaluated usingex vivo µCT80 images, histological examinations and energy dispersive x-ray spectroscopy analysis. The La2 scaffolds showed inhomogeneous and rapid degradation, with inferior osseointegration as compared to LAE442. For the early observation times, no bone and tissue could be observed in the pores of La2. Furthermore, the excessive amount of foreign body cells and fibrous capsule formation indicates insufficient biocompatibility of the La2 scaffolds. In contrast, the LAE442 scaffolds showed slow degradation and better osseointegration. Good vascularization, a moderate cellular response, bone and osteoid-like bone matrix at all implantation periods were observed in the pores of LAE442. In summary, porous LAE442 showed promise as a degradable scaffold for bone defect repair, based on its degradation behaviour and biocompatibility. However, further studies are needed to show it would have the necessary mechanical properties required over time for weight-bearing bone defects.

The effects of severe plastic deformation on the mechanical and corrosion characteristics of a bioresorbable Mg-ZKQX6000 alloy.

In this work, a bioresorbable Mg-ZKQX6000 (Mg-6Zn-0.6Zr-0.4Ag-0.2Ca (wt%)) alloy was severely plastically deformed via equal channel angular pressing (ECAP) according to three unique hybrid routes at low temperatures (200 °C to 125 °C). The roles of ECAP processing on microstructure, and ensuing mechanical properties and corrosion rates, are assessed. Microstructurally, ECAP induces a complex plethora of features, especially variations in grain sizes and precipitates' sizes, distributions, and morphologies for individual cases. Mechanically, ECAP generally refined grain size, resulting in ultra-high strength levels of about 400 MPa in ultimate tensile strength for several cases; however, deformation via ECAP of precipitates induced embrittlement and low elongation to failure levels. Corrosion testing, conducted in simulated bodily fluid at bodily pH levels to mimic conditions in the human body, revealed consistent corrosion rates across several techniques (mass loss, hydrogen evolution, and electrochemical impedance spectroscopy (EIS)), showing that severe plastic deformation deteriorates corrosion resistance for this material. In-situ corrosion monitoring explained that corrosion accelerated after ECAP due to the creation of heterogeneous, anodic shear zones, which exhibited dense regions of refined grains and fine precipitates. Suggestions for future design and thermomechanical processing of Mg alloys for bioresorbable orthopedic implants are provided.

[Disfiguring neurinoma of the nose tip and the columella-rhinosurgical aspects]. / Dysfigurierendes Neurinom der Nasenspitze und der Columella ­ rhinochirurgische Aspekte.

Neurinomas in the nose and the nasal sinuses are rare. In the present work, we present an exceedingly rare case of a disfiguring neurinoma involving the nasal columella. Treatment of choice is complete resection of the tumor. For an optimal view for tumor resection and esthetic and functional reconstruction, we recommend an open surgical approach.

Sunbed use legislation in Europe: assessment of current status.

BACKGROUND: The use of UV-emitting tanning devices for cosmetic purposes is associated with an increased risk of melanoma and non-melanoma skin cancer. Young women are the most frequent users, therefore, there is an increasing concern about the regulation of sunbed use. OBJECTIVE: The primary objective is to assess the current legislation on sunbed use among European countries. METHODS: We developed a 30-item questionnaire to gather the most relevant information about sunbed use legislation. The questionnaire was sent to Euromelanoma coordinators and to designated coordinators out of the Euromelanoma network. RESULTS: We obtained a response rate of 64%. More than 25% of the countries did not report any specific legislation. Roughly one-third of the countries does not have a restriction for minors. Even in countries with a specific legislation, a lack or insufficient enforcement of age limit was observed in up to 100% of the inspections based on the PROSAFE report from 2012. Self-tanning devices were reported in 50%, and almost 40% of countries do not require supervision of use. Although a warning display is required in 77% of cases, a signed informed consent is not required in 80%. In the vast majority of cases, the number of licensed or closed tanning centres is unknown. CONCLUSIONS: Despite the evidence of its harmful effects, and its frequent use by young people, many of whom are at high risk of skin cancer because of fair skin, a significant number of European countries lack a specific legislation on tanning devices. In order to limit the access of young people to sunbeds, a more strictly enforced regulation is needed, as well as regulation regarding advertisement, and location of tanning centres, in addition to health promotion campaigns that target the vulnerable population of young women seeking its use for improved cosmesis.

Open Management of the Renal Vein Is a Safe Modification in Right-Sided Laparoscopic Living Donor Nephrectomy to Maximize Graft Vein Length.

BACKGROUND: The primary objective in living donor kidney transplantation is donor safety. In laparoscopic living donor nephrectomy, most centers prefer the left kidney for donation given the shorter renal vein, higher rate of thromboses, and more difficult surgical procedure for right kidney retrieval. The goal of this study was to demonstrate the feasibility of a hybrid technique using a Satinsky clamp in right-sided living donor nephrectomy to obtain maximal renal vein and to compare the outcome with standard left-sided laparoscopic donor nephrectomies. MATERIAL AND METHODS: Between 2005 and 2013, 77 patients underwent a left (group L) and 54 a right (group R) living donor nephrectomy. In group R, after laparoscopic dissection and mobilization of the right kidney, two 12-mm trocar incisions in the right upper quadrant were connected in a 5-7 cm subcostal incision. The caval vein was partially clamped under direct vision prior to dissection of the renal vein. The venotomy was then closed with a running 4-0 Prolene suture. The two groups were compared with regard to surgical complications, graft function, and graft survival. RESULTS: Using this technique, no significant difference with regard to complications or graft function was observed. Serum creatinine at discharge in donor group L was 1.23 (±0.43) mg/dL and in donor group R 1.21 (±0.37) mg/dL (P = .71). Graft survival at one year was 100% in both groups. CONCLUSION: Open management of the renal vein is a safe alternative in laparoscopic right-sided donor nephrectomy and ensures maximal length of the vein.

Analysis of anti-tumour necrosis factor-induced skin lesions reveals strong T helper 1 activation with some distinct immunological characteristics.

BACKGROUND: Psoriasiform and eczematous eruptions are the most common dermatological adverse reactions linked to anti-tumour necrosis factor (TNF)-α therapy. Yet, a detailed characterization of their immune phenotype is lacking. OBJECTIVES: To characterize anti-TNF-α-induced inflammatory skin lesions at a histopathological, cellular and molecular level, compared with psoriasis, eczema (atopic dermatitis) and healthy control skin. METHODS: Histopathological evaluation, gene expression (quantitative real-time polymerase chain reaction) and computer-assisted immunohistological studies (TissueFAXS) were performed on 19 skin biopsies from patients with inflammatory bowel disease (n = 17) and rheumatoid arthritis (n = 2) with new-onset inflammatory skin lesions during anti-TNF-α-therapy. RESULTS: Although most biopsies showed a psoriasiform and/or spongiotic (eczematous) histopathological architecture, these lesions were inconsistent with either psoriasis or eczema on a molecular level using an established chemokine (C-C motif) ligand 27/inducible nitric oxide synthase classifier. Despite some differences in immune skewing depending on the specific histopathological reaction pattern, all anti-TNF-α-induced lesions showed strong interferon (IFN)-γ activation, at higher levels than in psoriasis or eczema. IFN-γ was most likely produced by CD3/CD4/Tbet-positive T helper 1 lymphocytes. CONCLUSIONS: New-onset anti-TNF-α-induced eruptions previously classified as psoriasis or spongiotic dermatitis (eczema) exhibit a molecular profile that is different from either of these disorders.

Reduction of permanent hearing loss by local glucocorticoid application : Guinea pigs with acute acoustic trauma.

BACKGROUND: High-intensity noise exposure from impulse and blast noise events often leads to acute hearing loss and may cause irreversible permanent hearing loss as a long-term consequence. Here, a treatment regime was developed to limit permanent damage based on a preclinical animal model of acute noise trauma. AIM: To develop clinical trials for the treatment of acute noise traumas using approved drugs. The otoprotective potential of glucocorticoids applied locally to the inner ear was examined. MATERIALS AND METHODS: A series of experiments with different impulse noise exposures were performed. Permanent hearing loss and hair cell density were assessed 14 days after exposure. Hearing and hair cell preservation were investigated as a function of the glucocorticoid dose. RESULTS: After impulse noise exposure, local application to the round window of the cochlea of high-dose prednisolone (25 mg/ml) or methylprednisolone (12.5 mg/ml) resulted in a statistically significant reduction in hearing loss compared with the control group. CONCLUSION: The local application of high doses of the drugs to the round window of the cochlea appears to be an effective treatment for acute noise trauma.

Balloon dilation of the Eustachian tube: clinical experience in the management of 126 children.

Balloon dilation of the Eustachian tube has been recently introduced as a novel and minimally invasive method for treating chronic obstructive Eustachian tube dysfunction. For the first time worldwide, we assessed the role of this technique in the treatment of children with Eustachian tube dysfunction who did not respond to other treatments. We retrospectively analysed the medical records of 60 children (mean age: 6.3 years, range: 28 months to 12 years) who underwent balloon dilation of the Eustachian tube using the Bielefeld balloon catheter. In addition, the parents of a further 66 children who underwent balloon dilation (mean age: 8 years, range: 4 to 13 years) were asked to complete a standardised written questionnaire and were interviewed by telephone about the postoperative course of their children. There were no complications during surgery. Clinical symptoms improved in more than 80% of patients. No patient reported a deterioration of symptoms. Of the participating parents, 81.3% were very satisfied or satisfied with the outcome of treatment. Balloon dilation is a rapid, simple and safe method for the treatment of both adults and children with Eustachian tube dysfunction that does not respond to other treatments. Further studies, ideally multicentre studies, are required in order to optimise the definition of existing and potential new indications for this treatment approach and to establish this treatment in the management of children with refractory chronic Eustachian tube dysfunction.

[Reduction of permanent hearing loss by local glucocorticoid application : Guinea pigs with acute acoustic trauma. German version]. / Begrenzung chronischer Hörverluste durch lokale Glukokortikoidgabe : Meerschweinchen mit akutem Lärmtrauma.

BACKGROUND: High-intensity noise exposure from impulse and blast noise events often leads to acute hearing loss and may cause irreversible permanent hearing loss as a long-term consequence. Here, a treatment regime was developed to limit permanent damage based on a preclinical animal model of acute noise trauma. AIM: To develop clinical trials for the treatment of acute noise traumas using approved drugs. The otoprotective potential of glucocorticoids applied locally to the inner ear was examined. MATERIALS AND METHODS: A series of experiments with different impulse noise exposures was performed. Permanent hearing loss and hair cell density were assessed 14 days after exposure. Hearing and hair cell preservation were investigated as a function of glucocorticoid dose. RESULTS: After impulse noise exposure, local application of high-dose prednisolone (25 mg/ml) or methylprednisolone (12.5 mg/ml) to the round window of the cochlea resulted in a statistically significant reduction in hearing loss compared to the control group. CONCLUSION: Local application of high doses of the drugs to the round window of the cochlea appears to be an effective treatment for acute noise trauma.

Optoacoustic effect is responsible for laser-induced cochlear responses.

Optical stimulation of the cochlea with laser light has been suggested as an alternative to conventional treatment of sensorineural hearing loss with cochlear implants. The underlying mechanisms are controversially discussed: The stimulation can either be based on a direct excitation of neurons, or it is a result of an optoacoustic pressure wave acting on the basilar membrane. Animal studies comparing the intra-cochlear optical stimulation of hearing and deafened guinea pigs have indicated that the stimulation requires intact hair cells. Therefore, optoacoustic stimulation seems to be the underlying mechanism. The present study investigates optoacoustic characteristics using pulsed laser stimulation for in vivo experiments on hearing guinea pigs and pressure measurements in water. As a result, in vivo as well as pressure measurements showed corresponding signal shapes. The amplitude of the signal for both measurements depended on the absorption coefficient and on the maximum of the first time-derivative of laser pulse power (velocity of heat deposition). In conclusion, the pressure measurements directly demonstrated that laser light generates acoustic waves, with amplitudes suitable for stimulating the (partially) intact cochlea. These findings corroborate optoacoustic as the basic mechanism of optical intra-cochlear stimulation.

Prevalence and audiological profiles of GJB2 mutations in a large collective of hearing impaired patients.

Mutations in the GJB2 gene are known to represent the commonest cause of hereditary and congenital hearing loss. In this study, a complete sequencing of the GJB2 gene in a cohort of 506 patients from a single, large cochlear implant program in Europe was performed. Audiological testing for those patients who could actively participate was performed using pure tone audiometry (PTA). Those unable to undergo PTA were measured using click-auditory brainstem response (ABR). Data analysis was performed to determine genotype-phenotype correlations of the mutational status vs. audiological profiles and vs. age at the time of presentation. An overall prevalence of biallelic mutations of 13.4% was found for the total collective. When subsets of younger patients were examined, the prevalence increased to 27% of those up to age 18 and 35% of those up to age 5 at the time of testing, respectively. This increase was found to be highly significant (p < 0.001). Analysis of the mean PTA thresholds revealed a strong correlation between allele combination status and mean PTA (p = 0.021). The prevalence of simple heterozygotes was found to be approximately 10.1%, which is around 3.3 times the value expected in the general population. As GJB2 follows a recessive pattern of inheritance, the question arises as to why such a large fraction of simple heterozygotes was observed among the hearing impaired patients included in this study.

An exploration of plastic deformation dependence of cell viability and adhesion in metallic implant materials.

The relationship between cell viability and adhesion behavior, and micro-deformation mechanisms was investigated on austenitic 316L stainless steel samples, which were subjected to different amounts of plastic strains (5%, 15%, 25%, 35% and 60%) to promote a variety in the slip and twin activities in the microstructure. Confocal laser scanning microscopy (CLSM) and field emission scanning electron microscopy (FESEM) revealed that cells most favored the samples with the largest plastic deformation, such that they spread more and formed significant filopodial extensions. Specifically, brain tumor cells seeded on the 35% deformed samples exhibited the best adhesion performance, where a significant slip activity was prevalent, accompanied by considerable slip-twin interactions. Furthermore, maximum viability was exhibited by the cells seeded on the 60% deformed samples, which were particularly designed in a specific geometry that could endure greater strain values. Overall, the current findings open a new venue for the production of metallic implants with enhanced biocompatibility, such that the adhesion and viability of the cells surrounding an implant can be optimized by tailoring the surface relief of the material, which is dictated by the micro-deformation mechanism activities facilitated by plastic deformation imposed by machining.

A novel biodegradable frontal sinus stent (MgNd2): a long-term animal study.

The frontal sinus recess consists of anatomically narrow passages that are prone to stenosis in endonasal frontal sinus surgery for chronic sinus disease. Over the past 100 years, diverse frontal sinus stents have been developed and evaluated in clinical and animal studies. However, superinfection, formation of granulations tissue, stent dislocation and late stenosis of the duct have remained challenges and subject of debate in the literature. Currently developed biodegradable materials, including rare earth-containing magnesium alloys are promising candidates for application as temporary implant materials. The Mg 2 % wt Nd alloy (MgNd2) was used to design a nasal stent that fit the porcine anatomy. In the current study, we evaluate biocompatibility, biodegradation and functionality of a frontal sinus stent in 16 minipigs over 6 months. Intraoperative endoscopy revealed free stent lumen in all cases. Blood examination and clinical examinations indicated no systematic or local inflammation signs. The histopathology and elements analysis showed a very good biocompatibility. The µ-computed tomography-based volumetric analysis showed substantial stent degradation within 6 months. Our MgNd2 based stent appears to be a promising, solid basis for the development of a frontal sinus stent for clinical use.

Exogenous Lipocalin 2 Ameliorates Acute Rejection in a Mouse Model of Renal Transplantation.

Lipocalin 2 (Lcn2) is rapidly produced by damaged nephron epithelia and is one of the most promising new markers of renal injury, delayed graft function and acute allograft rejection (AR); however, the functional importance of Lcn2 in renal transplantation is largely unknown. To understand the role of Lcn2 in renal AR, kidneys from Balb/c mice were transplanted into C57Bl/6 mice and vice versa and analyzed for morphological and physiological outcomes of AR at posttransplantation days 3, 5, and 7. The allografts showed a steady increase in intensity of interstitial infiltration, tubulitis and periarterial aggregation of lymphocytes associated with a substantial elevation in serum levels of creatinine, urea and Lcn2. Perioperative administration of recombinant Lcn2:siderophore:Fe complex (rLcn2) to recipients resulted in functional and morphological amelioration of the allograft at day 7 almost as efficiently as daily immunosuppression with cyclosporine A (CsA). No significant differences were observed in various donor-recipient combinations (C57Bl/6 wild-type and Lcn2(-/-) , Balb/c donors and recipients). Histochemical analyses of the allografts showed reduced cell death in recipients treated with rLcn2 or CsA. These results demonstrate that Lcn2 plays an important role in reducing the extent of kidney AR and indicate the therapeutic potential of Lcn2 in transplantation.

MgNd2 alloy in contact with nasal mucosa: an in vivo and in vitro approach.

Biodegradable and biocompatible magnesium alloys appear to be very promising not only for temporary clinical application but also for developing deformable and degradable medical implants. This study analyzes the in vivo degradation behavior and the impact on the paranasal sinuses of the highly ductile Mg-2 wt%Nd alloy (MgNd2) in order to provide a basis for a satisfying stent system for the therapy of a chronic sinusitis. Moreover, in vitro tests were carried out on primary porcine nasal epithelial cells (PNEC). For the in vivo tests, cylindrical MgNd2 specimens were implanted into the sinus' mucosa of minipigs. During and after a total period of 180 days the long-term biodegradation and biocompatibility properties after direct contact with the physiological tissue were analyzed. Biodegradation was investigated by measuring the mass and volume losses of the MgNd2 specimens as well as by performing element analyses to obtain information about the degradation layer. The influence on the surrounding tissue of paranasal sinuses was evaluated by endoscopic and histopathological examinations of the mucosa. Here, only a locally unspecific chronic infection was found. The degradation rate showed a maximum after 45 days postsurgery and was determined to decrease subsequently. In vitro experiments using PNEC showed adequate biocompatibility of MgNd2. This study demonstrates a good in vivo biocompatibility for MgNd2 in the system of paranasal sinuses and underlines the promising properties of alloy MgNd2 for biodegradable nasal stent applications.

[Small cell structured cell nests of endometrial stroma]. / Kleinzellig strukturierte Zellnester des Endometriumstromas.

Tissue from endometrial diagnostic curettage material may show small clumps of stromal cells, which are pushed together (stromal collapse) and present a picture of glandular and stromal breakdown. This can be misinterpreted as small cell structured carcinoma, possibly of neuroendocrine or basal cell origin. Immunohistochemical investigations (e.g. estrogen receptor, epithelial and neuroendocrine markers and proliferation markers) are helpful in identifying the correct differential diagnosis.

[Adaptive desensitization for acetylsalicylic acid hypersensitivity: A success story?]. / Adaptive Desaktivierung bei ASS-Hypersensitivität: Eine Erfolgsgeschichte?

BACKGROUND: Adaptive desensitization still remains the only causative therapy for acetylsalicylic acid (ASA) hypersensitivity and is carried out nearly worldwide. To date there are hardly any data available on disease development under current desensitization therapy and longitudinal data in particular are missing. STUDY DESIGN: Out of a large collective of patients with proven hypersensitivity to ASA, 194 patients with initiated desensitization treatment were observed for periods up to 5 years (average 32 months). RESULTS: Patients with immediate reactions to systemic challenge tests revealed a response rate of 77% after 12 months of therapy. In this period 12% reached complete remission, 38% showed a clear reduction in symptoms, 32% reached partial remission, 13% remained unchanged and 5% suffered from disease progression. CONCLUSION: Adaptive desensitization therapy for hypersensitivity to ASA has been shown to be an effective causative therapy and chronic hyperplastic sinusitis as well as bronchial asthma could be improved. For the determination of maintenance dosages and required time periods more data are needed.

[Intratympanic injection therapy for therapy refractory acute hearing loss: A safe option for secondary treatment]. / Intratympanale Injektionstherapie bei therapierefraktärem Hörsturz: Eine sichere Therapieoption zur Sekundärtherapie.

BACKGROUND: High-dose corticosteroids are currently recommended for idiopathic sudden sensorineural hearing loss (ISSNHL) treatment. Intratympanic injections (ITI) are of growing importance, especially in cases of therapy resistance. The selection of patients for this procedure in SSNHL has not been adequately examined so far. STUDY DESIGN: A total of 77 patients with ISSNHL after ineffective systemic pretreatment underwent intratympanic administration of dexamethasone and hyaluronic acid. Improvement after treatment was determined by pure tone audiometry for both ears before and of the treated ear after ITI. RESULTS: In this study 34 female and 43 male patients with mean age of 57 years showed a pre-ITI hearing loss of 35 dB in the lower frequencies and 69 dB in the higher frequencies. The mean hearing gain was 10 dB and the response rate was 62%. Absolute hearing gain revealed significant improvements at 500 Hz, 1 kHz and 2 kHz. Under inclusion of contralateral thresholds there were hardly any differences up to 4 kHz. In a detailed analysis of responders moderate improvements could be observed even in higher frequencies. Overall, no relevant adverse events occurred. CONCLUSION: Treatment of ISSNHL resistant to systemic regimens by ITI of steroids provides an option that offers additional prospects of auditory improvement for affected patients. The presented results indicate that these modalities are also valid for patients with pancochlear ISSNHL.

[Carotid aneurysm as a differential diagnosis of a cervical tumor]. / Karotisaneurysma als Differenzialdiagnose eines Halstumors.

This article presents the case of a patient with a submandibular cervical tumor initially suspected to be a large lymph node or glomus tumor. However, the diagnostic workup prior to taking a biopsy sample revealed an extracranial aneurysm of the internal carotid artery. In order to prevent a permanent neurologic deficit arising from thromboembolism, the aneurysm was excluded by resection and arterial continuity was restored. Extracranial aneurysms of the internal carotid artery are rare, but serious differential diagnoses of cervical nodes. It is of paramount importance that this differential diagnosis be considered before initiating invasive diagnostics of these tumors.