Reconstructive ossiculoplasty options in primary cholesteatoma surgeries with an intact stapes

PURPOSE

In primary cholesteatoma patients, incus destruction with an intact and mobile stapes is a frequent finding. Different techniques have been described to restore the ossicular chain, including incus interposition, stapes augmentation and type III tympanoplasty. Controversy about postoperative hearing results in open versus closed surgical techniques exist.

METHODS

We performed a retrospective analysis of clinical, surgical and audiometric data of patients with primary cholesteatoma surgery operated between 2010 and 2020, and a mobile stapes and one-stage ossicular reconstruction. Pre- and post-operative audiograms were compared for the different surgical groups, mainly focusing on postoperative air-bone gap. Mastoid pneumatization and ventilation was also considered.

RESULTS

The mean postoperative air-bone gap (0.5-4 kHz) of the 126 included patients was 20 dB. Hearing after type III tympanoplasty (26 dB) was worse than incus interposition (19 dB) and stapes augmentation (20 dB). Hearing after an open (23 dB) versus closed (19 dB) surgical technique was significantly different. No improvement in air-bone gap was observed for the higher frequencies.

CONCLUSION

A residual postoperative air-bone gap should be considered after primary cholesteatoma surgery with intact and mobile stapes. Incus interposition in closed cavity operation is the optimal situation, but open cavity surgery should not be avoided because of hearing. Extent of the disease is prioritized and poorer ventilation before and after surgery may affect postoperative hearing.

Combining bioengineered human skin with bioprinted cartilage for ear reconstruction

Microtia is a congenital disorder that manifests as a malformation of the external ear leading to psychosocial problems in affected children. Here, we present a tissue-engineered treatment approach based on a bioprinted autologous auricular cartilage construct (EarCartilage) combined with a bioengineered human pigmented and prevascularized dermo-epidermal skin substitute (EarSkin) tested in immunocompromised rats. We confirmed that human-engineered blood capillaries of EarSkin connected to the recipient's vasculature within 1 week, enabling rapid blood perfusion and epidermal maturation. Bioengineered EarSkin displayed a stratified epidermis containing mature keratinocytes and melanocytes. The latter resided within the basal layer of the epidermis and efficiently restored the skin color. Further, in vivo tests demonstrated favorable mechanical stability of EarCartilage along with enhanced extracellular matrix deposition. In conclusion, EarCartilage combined with EarSkin represents a novel approach for the treatment of microtia with the potential to circumvent existing limitations and improve the aesthetic outcome of microtia reconstruction.

Impact of manual crimping on stapedotomy outcomes

BACKGROUND

The impact of tight stapes crimping on hearing is a matter of debate. Several studies postulate that tight crimping is essential for lifelong success, whereas others have debated whether firm attachment leads to incus necrosis. Several types of prostheses with different coupling mechanisms have been developed, and manual crimping remains the most frequently used technique. This study investigates whether tightness really does affect hearing outcome.

METHODS

The hearing results of patients who underwent primary stapedotomies using three different titanium pistons were analysed. The surgeons categorised the firmness of the piston attachment into 'tight' and 'loose' crimping groups. Hearing outcome and reasons for revision surgical procedures were investigated.

RESULTS

The mean post-operative air-bone gap for frequencies of 0.5-4 kHz was 8.80 dB for the tight crimping group (n = 308) and 9.55 dB for the loose crimping group (n = 39). No significant difference was found (p = 0.4650). Findings at revision procedures were comparable (1.6 per cent vs 5 per cent).

CONCLUSION

Although firm crimping is strongly advised, a movable loop upon palpation does not lead to unsatisfactory hearing results, and does not mandate piston replacement or bone cement use.

Congenital aural atresia: hearing rehabilitation using active middle-ear implants

OBJECTIVE

To assess hearing rehabilitation in patients with congenital aural atresia using an active middle-ear implant (Vibrant Soundbridge).

METHODS

Of a cohort of 70 microtia and atresia patients, 10 underwent Vibrant Soundbridge implantation between 2008 and 2021. Two of the 10 patients had binaural implantation, resulting in 12 ears for analysis. Pre- and post-operative audiometry data were analysed, and patient satisfaction was evaluated. Surgical issues regarding coupling sites and outcomes were analysed.

RESULTS

Pure tone average (0.5, 1, 2 and 4 kHz) improved from a pre-operative mean (standard deviation) of 65.3 (8.7) dB HL to a post-operative mean of 26.8 (4.9) dB HL. This resulted in a mean pure tone average gain of 38.5 dB HL. The results indicate no obvious difference between stapes (n = 8) and incus (n = 4) coupling. The mean effective gain for 0.5, 1, 2 and 4 kHz was -17.8 dB HL (standard deviation = 4.3). Concerning effective gain, Vibrant Soundbridge performed best at 2 kHz. Patients reported high overall satisfaction, good sound quality and strongly improved directional hearing.

CONCLUSION

An active middle-ear implant (Vibrant Soundbridge) allows hearing rehabilitation in selected atretic ears, and provides long-term hearing stability in children and adults.

[Role of computed tomography in the preoperative diagnosis of otosclerosis]

BACKGROUND

Otosclerosis is an osteodystrophy of the otic capsule and presents with progressive conductive hearing loss. Imaging studies, especially computed tomography (CT) and cone-beam CT, have gained increased relevance in the diagnosis of otosclerosis.

OBJECTIVE

This study investigated whether there is a correlation between the extent of otosclerosis in high-resolution or cone-beam CT and hearing loss in pure-tone audiometry.

MATERIALS AND METHODS

Based on an existing classification of otosclerotic foci, a classification was established. Preoperative CT scans of patients undergoing stapedotomy between 2015 and 2019 were evaluated and classified by two independent otorhinolaryngologists. The preoperative pure-tone audiograms were analysed and compared to the results of CT.

RESULTS

A total of 168 CT studies (i.e., 168 ears) in 156 patients with intraoperatively confirmed otosclerosis were included in our study. A correlation between the extent of the otosclerotic focus or the calculated scores and hearing loss in pure-tone audiometry (air conduction, bone conduction and air-bone-gap) could not be proven.

CONCLUSION

Preoperative CT is not obligatory. However, preoperative imaging using CT or cone-beam CT can be helpful to confirm the diagnosis and exclude other middle or inner ear pathologies as well as in planning of the surgical procedure in the overall context of otoscopy and audiometry. A correlation with the degree of hearing impairment could not be demonstrated and remains unclear.

Multicenter Results With an Active Transcutaneous Bone Conduction Implant in Patients With Single-sided Deafness

OBJECTIVE

To evaluate the audiological and subjective benefit from hearing rehabilitation with an active bone conduction implant in subjects with single-sided sensorineural deafness (SSD).

STUDY DESIGN

Prospective, multicenter, single-subject repeated measures.

SETTING

Tertiary referral center, five clinics in Germany and Switzerland.

PATIENTS

Seventeen subjects aged 18 years and older with severe to profound unilateral sensorineural hearing loss and contralateral normal hearing were followed up for 24 months.

INTERVENTION

Active bone conduction implant.

MAIN OUTCOME MEASURES

Speech understanding in noise was assessed in three situations: with signal from front, deaf, or normal hearing side (with noise from front in all set-ups). Subjective benefit was evaluated using the Speech, Spatial, and Qualities of Hearing (SSQ-B) and Bern Benefit in Single-Sided Deafness (BBSS) questionnaire.

RESULTS

When the signal was coming from the deaf side the mean improvement of the speech reception threshold in noise ranged from 1.5 up to 2.2 dB with the device and was statistically and clinically significant at all tested timepoints. No significant difference between the aided and unaided situation was found when signal and noise were coming from the front. With the signal from the normal hearing side no clinically significant difference, that is, greater than 1 dB between the aided and unaided situation was found. The SSQ-B and BBSS questionnaire showed an overall improvement with no significant difference between time points.

CONCLUSIONS

The study demonstrates long-term efficacy and benefit of the device in adults with SSD. Patients reported substantial and persistent subjective benefit from the active bone conduction implant.

[Treatment of single-sided deafness by cochlear implantation]

Single sided deafness diminishes speech understanding in noise and sound localization and thereby globally auditory performance. Most patients also suffer from tinnitus and indicate reduced quality of life. Patients have the choice to adapt to the new situation without treatment, to restore pseudostereophonic hearing by contralateral routing of signal (CROS) hearing aids or to restore binaural hearing using a cochlear implant in the deaf ear. This article summarizes the physiological base of binaural hearing and treatment options for single sided deafness with a special emphasis on the cochlear implant.

Tympanoplasty with an Intact Stapes Superstructure in Chronic Otitis Media

BACKGROUND

The objective of our study was to ascertain the functional results in terms of air bone gap (ABG) closure over 4 frequencies (0.5, 1, 2, 3 kHz) in patients with chronic otitis media (COM) that underwent tympanoplasty in the presence of a mobile stapes superstructure, and in particular excluding those cases in which the malleus was used in the reconstruction.

METHODS

A retrospective review of our database between January 1, 2006 and June 1, 2018 identified all cases that underwent one of 3 reconstructive options: the classic Type III tympanoplasty in an open-cavity setting; the "stapes augmentation" (SA) type reconstruction where the stapes superstructure is augmented to the drum by an interposing partial ossiculoplasty of either autologous bone, cartilage, or prosthetic material; and the use of a total articular replacement prosthesis (TORP) from the stapes footplate to the drum in the presence of an intact superstructure.

RESULTS

A total of 116 procedures in 112 patients were identified with a mean ABG reduction from 27 dB to 21 dB (P < .05). There was no significant difference in the mean post-operative ABG result between Type III (19.21 dB), TORP+ (24.90 dB), or SA (20.94 dB) reconstructions (P = .368). Overall, an ABG ≤ 20 dB or "surgical success" was achieved in 56% (n = 65) of cases. Only 20% (n = 23) of cases had "failure" or a post-operative ABG >30 dB.

CONCLUSION

Tympanoplasty with an intact stapes superstructure in COM is expected to provide acceptable levels of surgical success. We did not identify any particular risk factors associated with improved outcome.

Characterization of a Structural Leoligin Analog as Farnesoid X Receptor Agonist and Modulator of Cholesterol Transport

The ligand-activated farnesoid X receptor is an emerging therapeutic target for the development of drugs against metabolic syndrome-related diseases. In this context, selective bile acid receptor modulators represent a novel concept for drug development. Selective bile acid receptor modulators act in a target gene- or tissue-specific way and are therefore considered less likely to elicit unwanted side effects. Based on leoligin, a lignan-type secondary plant metabolite from the alpine plant Leontopodium nivale ssp. alpinum, 168 synthesized structural analogs were screened in a farnesoid X receptor in silico pharmacophore-model. Fifty-six virtual hits were generated. These hits were tested in a cell-based farnesoid X receptor transactivation assay and yielded 7 farnesoid X receptor-activating compounds. The most active one being LT-141A, with an EC₅₀ of 6 µM and an E_max of 4.1-fold. This analog did not activate the G protein-coupled bile acid receptor, TGR5, and the metabolic nuclear receptors retinoid X receptor α, liver X receptors α/β, and peroxisome proliferator-activated receptors β/γ. Investigation of different farnesoid X receptor target genes characterized LT-141A as selective bile acid receptor modulators. Functional studies revealed that LT-141A increased cholesterol efflux from THP-1-derived macrophages via enhanced ATP-binding cassette transporter 1 expression. Moreover, cholesterol uptake in differentiated Caco-2 cells was significantly decreased upon LT-141A treatment. In conclusion, the leoligin analog LT-141A selectively activates the nuclear receptor farnesoid X receptor and has an influence on cholesterol transport in 2 model systems.

Intratemporal facial nerve schwannomas: multicenter experience of 80 cases

PURPOSE

To provide more data on the clinical presentation and natural evolution of facial nerve schwannomas and to provide guidance for therapeutic decision making.

METHODS

A retrospective case review of eighty patients diagnosed with a facial nerve schwannoma between 1990 and 2018 in ten tertiary referral centers in Europe was performed. Patients' demographics, symptomatology, audiometry, anatomical site (segments involved), size and whenever possible volume measurement were registered.

RESULTS

At presentation, transient or persistent facial palsy was the most common symptom, followed by hearing loss. The schwannoma involved more than one segment in the majority of the patients with the geniculate ganglion being most commonly involved. Initial treatment consisted of a wait and scan approach in 67.5%, surgery in 30% and radiation therapy in 2.5% of the patients. Tympanic segment schwannomas caused mainly conductive hearing loss and were more prone to develop facial palsy at follow-up. Internal auditory canal or cerebellopontine angle schwannomas presented with significantly more sensorineural hearing loss.

CONCLUSIONS

Although modern imaging has improved diagnosis of this tumor, choosing the best treatment modality remains a real challenge. Based on the literature review and current findings, more insights into the clinical course and the management of facial nerve schwannomas are provided.

[The comparison of malleostapedotomy in primary and revision stapes surgery for otosclerosis]

Objective: To compare the effectiveness of primary malleostapedotomy with revision malleostapedotomy for otosclerosis. Methods: From April 2002 to December 2017, 70 consecutive patients with otosclerosis who underwent malleostapedotomy were reviewed. Depending on the primary malleostapedotomy (P-MS) or revision malleostapedotomy (R-MS), the patients were divided into P-MS group or R-MS group.The intraoperative findings and hearing results before and after surgery were compared between the two groups. ALL data were analyzed using SPSS 23. Results: Totally 73 malleostapedotomy were performed in 73 ears of 70 patients, including 38 P-MS and 35 R-MS. There was no significant difference between the two groups in sex ratio, age and operated ears (P>0.05 for all). The most common finding at P-MS was incus fixation (50.0%, 19/38) versus prosthesis displacement for R-MS (60.0%, 21/35) . Overall, the air-bone gap (ABG) improvement in P-MS were (18.1±8.2) dB in 0.5-3 kHz and (18.3±8.5) dB in 0.5-4 kHz, without significant difference to those in R-MS (P>0.05) . 31.4% of R-MS in 0.5-3 kHz and 22.9% R-MS in 0.5-4 kHz achieved an ABG<10 dB, significantly lower than those of P-MS (65.8% in 0.5-3 kHz and 57.9% in 0.5-4kHz; P<0.05). Failure (postoperative ABG>30 dB) occurred in 11.4% in R-MS and 0 in P-MS (for 0.5-3 kHz and 0.5-4 kHz). The incidence of postoperative sensorineural hearing loss (>10 dB increase in bone conduct) in R-MS group was 8.6% in 0.5-3 kHz and 0.5-4 kHz, without significant difference to those in P-MS (P>0.05) . 80.0% (20/25) of first R-MS achieved ABG<20 dB, compared to 37.5% (3/8) of second R-MS with ABG<20 dB. Conclusions: Although both P-MS and R-MS can significantly improve hearing, with similar risk of inner ear damage, R-MS is less effective and poses a higher risk of failure than P-MS. For patients with insufficient hearing improvement after first R-MS, conventional hearing aids or implantable hearing devices may be considered as an alternative.

Design and Synthesis of a Compound Library Exploiting 5-Methoxyleoligin as Potential Cholesterol Efflux Promoter

5-Methoxyleoligin and leoligin are natural occurring lignans derived from Edelweiss (Leontopodium nivale ssp. alpinum), displaying potent pro-angiogenic and pro-arteriogenic activity. Cholesterol efflux from macrophages is associated with reverse cholesterol transport which inhibits the development of cardiovascular disease. Within this study, we developed a modular and stereoselective total synthesis of 5-methoxyleoligin which can be readily used to prepare a novel compound library of related analogs. The target 5-methoxyleoligin was synthesized exploiting a recently disclosed modular route, which allows also rapid synthesis of analogous compounds. All obtained products were tested towards macrophage cholesterol efflux enhancement and the performance was compared to the parent compound leoligin. It was found that variation on the aryl moiety in 2-position of the furan ring allows optimization of the activity profile, whereas the ester-functionality does not tolerate significant alterations.

International Otology Outcome Group and the International Consensus on the Categorization of Tympanomastoid Surgery

The International Otology Outcome Group (IOOG) was founded in 2017 to encourage and facilitate international collaboration with regard to the surgical outcome of ear surgery. This report outlines the methodology and recommendations of the consensus-based categorization of tympanomastoid surgery produced by the IOOG. The IOOG Steering Committee used the acronym SAMEO-ATO to categorize tympanomastoid operations, representing the stage of surgery, approach, mastoid bone extirpation, external bony wall repair, obliteration of the mastoid cavity, access to the middle ear, tympanic membrane reconstruction, and ossicular reconstruction. A modified Delphi technique was used to obtain international consensus. The expert panels included the chairpersons from 21 otology societies. The approval rate of the SAMEO-ATO system from the otology societies was 95%. The SAMEO-ATO scheme was presented at the 31st Politizer Meeting for field testing. There were no objections or serious concerns raised. Some international otologists wished to see more surgical categories included to reflect the varieties of surgical techniques, but they accepted that it would make the whole system cumbersome. In addition to providing an international categorization of tympanomastoid surgery, the IOOG Steering Committee plans to introduce a common otology dataset that the international otology community could use to record their surgical outcome. The high level of international consensus on the IOOG categorization of tympanomastoid surgery supports this tool for surgeons to pool their surgical data into a large database for research and comparative audit.

Leoligin-inspired synthetic lignans with selectivity for cell-type and bioactivity relevant for cardiovascular disease

Recently, a natural compound leoligin, a furan-type lignan, was discovered as an interesting hit compound with an anti-inflammatory pharmacological activity profile. We developed a modular and stereoselective approach for the synthesis of the edelweiss-derived lignan leoligin and used the synthetic route to rapidly prepare leoligin analogs even on the gram scale. Proof of concept of this approach together with cell-based bio-assays gained structural analogs with increased selectivity towards vascular smooth muscle versus endothelial cell proliferation inhibition, a major benefit in fighting vascular neointima formation. In addition, we identified the structural features of leoligin analogs that define their ability to inhibit the pro-inflammatory NF-κB pathway. Results are discussed in the context of structural modification of these novel synthetic lignans.

Eight Items to Check on a Temporal Bone CT-Scan

Imaging data provided by computed tomography scans of the temporal bone are fundamental for both the diagnosis and treatment of diseases affecting this complex structure. Despite its importance, the expertise required to analyze this exam is seldom properly acquired as it is time-consuming and often neglected among young doctors and even otolaryngologists. Physicians may not even have a look at the scans but rely only on radiology reports. Radiologists, on the other hand, may not describe the individual scans the same way as clinicians. Lack of a standardized and didactic protocol for scrolling through the images obtained might also contribute to the difficulties reported by residents and physicians in daily practice. We present here a sequential checklist which could be employed in a systematic and organized manner, aiming to both develop and practice the know-how of this indispensable and challenging method of evaluation of the temporal bone.

One-pot synthesis of triazines as potential agents affecting cell differentiation

Abstract

This paper outlines the synthesis of a number of structural analogs of 3-[(4,6-diphenoxy-1,3,5-triazin-2-yl)amino]benzoic acid which represent compounds with potential cardiogenetic activity. A one-pot protocol was developed for swift functionalization of the 1,3,5-triazine core without the need of isolating intermediates. The developed route starts from readily available 2,4,6-trichloro-1,3,5-triazine, displacing the chlorine atoms sequentially by aryloxy, arylamino, or arylthio moieties to enable access to molecules with three different substituents of this type in good yields. To facilitate purification, tert-butyl, methyl, and ethyl ester derivatives of the target compounds were initially synthesized. The tert-butyl esters could be readily hydrolyzed to the desired compounds, while reduction of the methyl and ethyl esters gave the corresponding benzylic alcohols in high yields, thereby expanding the substrate scope for future relevant cell assays.

Graphical abstract

Risk factors for hypocalcaemia after completion hemithyroidectomy in thyroid cancer

BACKGROUND

Hypocalcaemia (HC) is the most common complication after thyroid surgery in differentiated thyroid cancer and leads to a prolongation of the hospital stay. While risk factors for HC after total thyroidectomy (TE) are well investigated, only few studies have been published about HC risk factors after completion of thyroidectomy. Our aim was to identify potential risk factors for HC after completion of TE and to compare these incidences with figures from primary total TE.

MATERIALS AND METHODS

A retrospective cohort study was undertaken including patients undergoing completion of TE between 2002 and 2013 in our tertiary care centre. Patients with hypocalcaemia (group 1) after undergoing second surgery were compared to normocalcaemia patients (group 2) with respect to gender, age, type of thyroid cancer, time interval between surgeries, pre/postoperative calcium and parathyroid hormone (PTH) levels, clinical hypocalcaemia signs and calcium substitution (intravenous, oral). Hypocalcaemia was defined as <2.10 mmol/l, hypoparathyroidism as <15pg/ml.

RESULTS

34 (25 female, 9 male) patients were included. A total of 12 patients (33%) developed a hypocalcaemia (group 1). Three patients out of these also presented with hypoparathyroidism. One patient in each group showed clinical signs of hypocalcaemia. Calcium substitution was necessary in six cases in group 1 and in one case in group 2. There was a significant difference between the groups concerning postoperative PTH (25.1 vs 37.6 pg/ml) and calcium levels (1.87 vs 2.27 mmol/l) (p <0.05). Group comparison shows no significant relationships between all other parameters (age, gender, type of thyroid cancer and duration of interval between surgeries). Logistic regression analysis identified a low preoperative serum calcium level as the only dominant factor indicating postoperative hypocalcaemia.

CONCLUSIONS

A hypocalcaemia rate of 33% (12/34) and a hypoparathyroidism rate of 9% (3/34) after completion of thyroidectomy in our cohort is comparable to primary total thyroidectomy. A low preoperative calcium level is a significant risk factor for postoperative hypocalcaemia after completion of thyroidectomy. The prediction of hypocalcaemia still remains difficult since it has multifactorial causes.

Titanium incus interposition ossiculoplasty: audiological outcomes and extrusion rates

This study aimed to evaluate the benefit but also the extrusions, dislocations, and failures of a titanium incus prosthesis along with the long-term audiological outcomes. We prospectively collected data from 139 patients undergoing ossiculoplasty using the Fisch titanium incus prosthesis between 2001 and 2016. Overall, 126 patients with at least 6 months of follow-up (mean 4.5 years, range 6-155 months) were analyzed. Patients were grouped as "extrusion" (n = 9, 7%) if the prosthesis extruded, "failure" (n = 22, 18%) if a reoperation was needed concerning the prosthesis, and "stable" (n = 95, 75%) if the prosthesis remained functional in the middle ear. Mean postoperative air bone gaps (ABG) for 0.5-3 kHz for the overall group and the stable group were 19.8 (±11.9) and 15.3 (±7.5), respectively. Long-term results of stable group revealed an ABG (0.5-3 kHz) below 10 dB in 25% and below 20 dB in 81% of the patients. Atelectasis was the most frequent cause of extrusion, which occurred after a mean time of 28.7 months (range 15-48 months). Mean timing for reoperation was 30.7 months (range 5-131 months) in the failure group. There was no significant difference in mean postoperative ABG among patients with or without cholesteatoma, primary or staged ossiculoplasty in cholesteatoma, presence or absence of malleus head at the time of ossiculoplasty, open or closed cavity surgeries, or the degree of pneumatization of the temporal bone. The Fisch titanium incus prosthesis is a reliable alternative to using autologous incus for interposition ossiculoplasty, with similar hearing outcomes. Using this prosthesis, a 15 dB ABG should be expected.

Hypothyreose nach Hemithyreoidektomie − überraschend häufige Komplikation während der Nachsorge

Hintergrund Hemithyreoidektomie ist eine häufige Behandlung einseitiger Schilddrüsenknoten. Postoperative Hypothyreose ist eine häufig unterschätzte Komplikation. Wir untersuchten Inzidenz, Zeitpunkt, Symptomatik sowie mögliche Risikofaktoren der postoperativen Hypothyreose.

Material und Methoden 127 Patienten nach Hemithyreoidektomie wurden mit retrospektiver Datenanalyse sowie strukturierter Befragung der nachbetreuenden Hausärzte und Endokrinologen untersucht. Patienten wurden mit dem postoperativen TSH als hypothyreot (> 4.0 mU/L) oder euthyreot (0.4–4.0 mU/L) klassifiziert. Schilddrüsenhormone wurden nach 4–6 Wochen, 6 Monaten und 1 Jahr gemessen.

Ergebnisse 55 Patienten (43 %) entwickelten eine postoperative Hypothyreose und 72 (57%) blieben euthyreot. Die Hypothyreose zeigte sich innerhalb der ersten 2 Monaten bei 39 Patienten (71 %), zwischen 2–6 Monaten bei 13 Patienten (24 %) sowie nach 6–12 Monaten bei 3 Patienten (5 %). 33 Patienten (60 %) waren zum Zeitpunkt der Diagnose asymptomatisch. Nur 16 Patienten (29 %) hatten Symptome. Der präoperative TSH Wert war signifikant höher in der Gruppe der hypothyreoten Patienten (1.64), verglichen mit der euthyreoten Gruppe (1.13, P = 0.0017). Die anderen Variablen wie Alter, Geschlecht und präoperativen Werte von T3, T4, Calcium und PTH zeigten keinen signifikanten Unterschied.

Schlussfolgerung Die postoperative Hypothyreose ist eine häufige Komplikation nach Hemithyreoidektomie, welche nicht verpasst werden sollte. Präoperativ erhöhter TSH Wert ist ein Risikofaktor für die postoperative Hypothyreose. Alle Patienten nach Hemithyreoidektomie sollten postoperative TSH Kontrollen nach 4–6 Wochen, 6 Monaten und 12 Monaten haben.

Iatrogenic facial nerve injuries during chronic otitis media surgery: a multicentre retrospective study

OBJECTIVES

To give an insight into why, when and where iatrogenic facial nerve (FN) injuries may occur and to explain how to deal with them in an emergency setting.

DESIGN AND SETTING

Multicentre retrospective study in eight tertiary referral hospitals over 17 years.

PARTICIPANTS

Twenty patients with partial or total FN injury during surgery for chronic otitis media (COM) were revised.

MAIN OUTCOME MEASURES

Indication and type of surgery, experience of the surgeon, intra- and postoperative findings, value of CT scanning, patient management and final FN outcome were recorded.

RESULTS

In 12 cases, the nerve was completely transected, but the surgeon was unaware in 11 cases. A minority of cases occurred in academic teaching hospitals. Tympanic segment, second genu and proximal mastoid segments were the sites involved during injury. The FN was not deliberately identified in 18 patients at the time of injury, and nerve monitoring was only applied in one patient. Before revision surgery, CT scanning correctly identified the lesion site in 11 of 12 cases and depicted additional lesions such as damage to the lateral semicircular canal. A greater auricular nerve graft was interposed in 10 cases of total transection and in one partially lesioned nerve: seven of them resulted in an HB III functional outcome. In two of the transected nerves, rerouting and direct end-to-end anastomosis was applied. A simple FN decompression was used in four cases of superficially traumatised nerves.

CONCLUSIONS

We suggest checklists for preoperative, intraoperative and postoperative management to prevent and treat iatrogenic FN injury during COM surgery.

Leoligin, the Major Lignan from Edelweiss (Leontopodium nivale subsp. alpinum), Promotes Cholesterol Efflux from THP-1 Macrophages

Leoligin is a natural lignan found in Edelweiss (Leontopodium nivale ssp. alpinum). The aim of this study was to examine its influence on cholesterol efflux and to address the underlying mechanism of action. Leoligin increases apo A1- as well as 1% human plasma-mediated cholesterol efflux in THP-1 macrophages without affecting cell viability as determined by resazurin conversion. Western blot analysis revealed that the protein levels of the cholesterol efflux transporters ABCA1 and ABCG1 were upregulated, whereas the SR-B1 protein level remained unchanged upon treatment with leoligin (10 μM, 24 h). Quantitative reverse transcription PCR further uncovered that leoligin also increased ABCA1 and ABCG1 mRNA levels without affecting the half-life of the two mRNAs in the presence of actinomycin D, a transcription inhibitor. Proteome analysis revealed the modulation of protein expression fingerprint in the presence of leoligin. Taken together, these results suggest that leoligin induces cholesterol efflux in THP-1-derived macrophages by upregulating ABCA1 and ABCG1 expression. This novel activity suggests leoligin as a promising candidate for further studies addressing a possible preventive or therapeutic application in the context of atherosclerosis.

Discovery and resupply of pharmacologically active plant-derived natural products: A review

Medicinal plants have historically proven their value as a source of molecules with therapeutic potential, and nowadays still represent an important pool for the identification of novel drug leads. In the past decades, pharmaceutical industry focused mainly on libraries of synthetic compounds as drug discovery source. They are comparably easy to produce and resupply, and demonstrate good compatibility with established high throughput screening (HTS) platforms. However, at the same time there has been a declining trend in the number of new drugs reaching the market, raising renewed scientific interest in drug discovery from natural sources, despite of its known challenges. In this survey, a brief outline of historical development is provided together with a comprehensive overview of used approaches and recent developments relevant to plant-derived natural product drug discovery. Associated challenges and major strengths of natural product-based drug discovery are critically discussed. A snapshot of the advanced plant-derived natural products that are currently in actively recruiting clinical trials is also presented. Importantly, the transition of a natural compound from a "screening hit" through a "drug lead" to a "marketed drug" is associated with increasingly challenging demands for compound amount, which often cannot be met by re-isolation from the respective plant sources. In this regard, existing alternatives for resupply are also discussed, including different biotechnology approaches and total organic synthesis. While the intrinsic complexity of natural product-based drug discovery necessitates highly integrated interdisciplinary approaches, the reviewed scientific developments, recent technological advances, and research trends clearly indicate that natural products will be among the most important sources of new drugs also in the future.

Identification of the putative binding pocket of valerenic acid on GABAA receptors using docking studies and site-directed mutagenesis

Background and Purpose

β2/3‐subunit‐selective modulation of GABA_A receptors by valerenic acid (VA) is determined by the presence of transmembrane residue β2/3N265. Currently, it is not known whether β2/3N265 is part of VA's binding pocket or is involved in the transduction pathway of VA's action. The aim of this study was to clarify the localization of VA's binding pocket on GABA_A receptors.

Experimental Approach

Docking and a structure‐based three‐dimensional pharmacophore were employed to identify candidate amino acid residues that are likely to interact with VA. Selected amino acid residues were mutated, and VA‐induced modulation of the resulting GABA_A receptors expressed in Xenopus oocytes was analysed.

Key Results

A binding pocket for VA at the β⁺/α⁻ interface encompassing amino acid β3N265 was predicted. Mutational analysis of suggested amino acid residues revealed a complete loss of VA's activity on β3M286W channels as well as significantly decreased efficacy and potency of VA on β3N265S and β3F289S receptors. In addition, reduced efficacy of VA‐induced I_GABA enhancement was also observed for α1M235W, β3R269A and β3M286A constructs.

Conclusions and Implications

Our data suggest that amino acid residues β3N265, β3F289, β3M286, β3R269 in the β3 subunit, at or near the etomidate/propofol binding site(s), form part of a VA binding pocket. The identification of the binding pocket for VA is essential for elucidating its pharmacological effects and might also help to develop new selective GABA_A receptor ligands.

The use of subtotal petrosectomy in cochlear implant candidates with chronic otitis media

Cochlear implants (CI) candidates with chronic otitis media require special attention and management. The need of opening of the inner ear creates potential routes of spread of infection to subarachnoid spaces and lead to meningitis. The aim of the study was to analyse the technique and complications of subtotal petrosectomy (SP) in cochlear implant candidates with chronic otitis media at three different CI centres. A retrospective study was carried out in three Territory Referral Hospitals. The centres follow Fisch's philosophy and surgical techniques of SP. The study group consisted of 19 patients, 4 men and 15 women, aged 12-82 years. All patients underwent SP with either primary or staged CI implantation. Indications for single or a staged management, difficulties during surgery and complications were analysed. Skin and muscle flap design in primary and revision cases as well as imaging follow-up strategy are discussed. In 14 patients implantation was performed in a single stage and in 5 cases in two stages. Follow-up ranged from 8 months to 10 years. All the patients use their implants and there were no major nor minor complications. The use of subtotal petrosectomy with cochlear implants is a safe and efficient technique when strict surgical steps and rules are applied. Closure of the external ear canal after previous meatoplasty can be challenging and extreme care dissecting the skin flaps is required. In patients with extensive cholesteatoma, active discharge from the ear with resistant bacteria or an "unstable" situation, the procedure can be staged.

[Neuroendocrine adenoma of the middle ear]

BACKGROUND

Neuroendocrine adenomas of the middle ear are rare, low-grade neoplasms with potential for recurrence and metastasis. The nonspecific symptoms and preliminary clinical and radiological findings are misleading and often fail to provide the right diagnosis.

PATIENTS AND METHODS

We analyzed the findings of 3 adult patients, who were treated between 2001 and June /2012 at the Luzerner Kantonsspital in Switzerland.

RESULTS

The 3 patients reported on hearing loss, ear pressure and/or tinnitus. Otoscopy showed a thickened, intact tympanic membrane with a whitish-grayish prolapsing mass. All the patients had conductive hearing loss. Computer tomography showed an unspecified well-circumscribed soft-tissue mass. Definitive histology with immunostaining after radical tumor removal led to the proper diagnosis.

CONCLUSIONS

The typical constellation of nonspecific clinical and radiological findings leads to the right diagnosis of neuroendocrine adenoma of the middle ear. After reviewing the literature, we illustrate the differential diagnosis as well as the relevant diagnostic and therapeutic procedures, and remind ENT physicians about this rare disease entity.

Structure-activity relationships of pentamidine-affected ion channel trafficking and dofetilide mediated rescue

BACKGROUND AND PURPOSE

Drug interference with normal hERG protein trafficking substantially reduces the channel density in the plasma membrane and thereby poses an arrhythmic threat. The chemical substructures important for hERG trafficking inhibition were investigated using pentamidine as a model drug. Furthermore, the relationship between acute ion channel block and correction of trafficking by dofetilide was studied.

EXPERIMENTAL APPROACH

hERG and K(IR)2.1 trafficking in HEK293 cells was evaluated by Western blot and immunofluorescence microscopy after treatment with pentamidine and six pentamidine analogues, and correction with dofetilide and four dofetilide analogues that displayed different abilities to inhibit IKr . Molecular dynamics simulations were used to address mode, number and type of interactions between hERG and dofetilide analogues.

KEY RESULTS

Structural modifications of pentamidine differentially affected plasma membrane levels of hERG and K(IR)2.1. Modification of the phenyl ring or substituents directly attached to it had the largest effect, affirming the importance of these chemical residues in ion channel binding. PA-4 had the mildest effects on both ion channels. Dofetilide corrected pentamidine-induced hERG, but not K(IR)2.1 trafficking defects. Dofetilide analogues that displayed high channel affinity, mediated by pi-pi stacks and hydrophobic interactions, also restored hERG protein levels, whereas analogues with low affinity were ineffective.

CONCLUSIONS AND IMPLICATIONS

Drug-induced trafficking defects can be minimized if certain chemical features are avoided or 'synthesized out'; this could influence the design and development of future drugs. Further analysis of such features in hERG trafficking correctors may facilitate the design of a non-blocking corrector for trafficking defective hERG proteins in both congenital and acquired LQTS.

Labyrinthine fenestration for stapes fixation in chronic ear disease others than otosclerosis

The objective of this study is to assess the results of labyrinthine fenestration for fixed stapes in chronic ear disease. Using a prospective database, pre- and postoperative audiometric data from patients undergoing labyrinthine fenestration for fixation of the stapes in chronic ear disease others than otosclerosis between 2002 and 2012 were evaluated. Twenty-three labyrinthine fenestrations in chronic ear disease were performed (17 malleo-stapedotomies, 4 incus-stapedotomies, 1 neo-malleus-stapedotomy, 1 TORP-stapedotomy). Overall, the mean short-term (2 months) and long-term (42 months) postoperative air-bone gap (0.5-3 kHz) were 17.5 and 16.5 dB, respectively; long-term air-bone gap of <20 dB was obtained in 73 % of patients. There was no significant difference in air-bone gap closure between tympanosclerotic and post inflammatory osteogenic fixation of the stapes (p = 0.267). Hearing benefit success using the 'Belfast rule of the thumb' was achieved in 48 %. Normal bilateral hearing was achieved in 17 % and bilateral symmetric hearing impairment in 26 %. Only in 4 %, bone conduction worsened by more than 5 dB. Labyrinthine fenestration is an option in selected cases of stapes fixation in chronic ear disease and provides hearing gain without significant risk for sensorineural hearing loss. In those already selected cases, hearing benefit success 'Belfast rule of the thumb' is achieved only in half of the cases. This and the possible alternatives, should therefore be discussed preoperatively.

Functional correlations of tympanic membrane perforation size

OBJECTIVE

The correlation between tympanic membrane perforations and hearing loss was studied.

STUDY DESIGN

Prospective data from 220 patients, who underwent primary surgery for simple chronic otitis media with a perforated eardrum, were analyzed.

SETTING

Tertiary referral center.

PATIENTS

One hundred fifty-one patients with 155 eardrum perforations, which were checked for correct diagnosis, normal middle-ear status, and integrity of the ossicular chain, were included.

INTERVENTIONS

All patients underwent primary myringoplasty.

MAIN OUTCOME MEASURES

Preoperative conductive hearing loss due to eardrum perforations.

RESULTS

Hearing loss shows a linear relationship with increasing eardrum perforation size. Umbo involvement shows a worsening of the hearing by 5 to 6 dB (p < 0.0001). The least impact of a perforation is seen at the resonance frequency of 2 kHz. Above and below 2 kHz, an 'inverted V shape' of the air-bone gap is a consistent finding. If the air-bone gap exceeds the 'inverted V-shape' pattern, additional pathology behind the eardrum must be assumed and addressed.

CONCLUSION

We propose using standardized photographs or drawings to document preoperative perforation sizes. A linear relationship between the size of a perforation and the conductive hearing loss does exist. Umbo involvement at the perforation margin may worsen the hearing by 5 to 6 dB, whereas the position of the perforation itself does not play a role. The least impact of a perforation is seen at the resonance frequency of 2 kHz. An "inverted V-shape" pattern, above and below 2 kHz, of the air-bone gap is a consistent finding. If the air-bone gap exceeds this pattern, additional pathology behind the eardrum perforation must be assumed and addressed.

Synthesis of Novel Lithium Salts containing Pentafluorophenylamido-based Anions and Investigation of their Thermal and Electrochemical Properties

Three novel lithium salts, lithium bis(pentafluorophenyl)amide LiN(Pfp)2, lithium pentafluorphenyl(trifluormethylsulfonyl)imide LiN(Pfp)(Tf) and lithium pentafluorphenyl(nonafluorbutylsulfonyl)imide LiN(Pfp)(Nf) were synthesized and characterized with respect to their thermal and electrochemical properties. LiN(Pfp)2 decomposes at 108 ºC, whereas Li-N(Pfp)(Tf) and Li-N(Pfp)(Nf) show a much higher thermal stability of 307 ºC and 316 ºC, respectively. The ionic conductivity at 100 ºC measured by means of impedance spectroscopy decreases in the order LiN(Pfp)(Tf) > LiN(Tf)2 > LiN(Pfp)(Nf). Both, the activation energy and entropy for ion conduction in the new salts are lower than in LiN(Tf)2 (LiTFSI), most likely due to the lower symmetry of the new anions. The electrochemical stability and ionic conductivity of LiN(Pfp)(Tf) and LiN(Pfp)(Nf) solutions (0.1 mol/l) in ethylene carbonate/dimethyl carbonate (1:3 w/w) are slightly lower than those of the LiTFSI solution, but still sufficient for application in lithium ion batteries. The high thermal stability of the novel salts and their stability towards hydrolysis makes them attractive candidates for overcoming the drawbacks of LiPF6-based electrolytes at elevated temperatures.

Catechol alkenyls from Semecarpus anacardium: acetylcholinesterase inhibition and binding mode predictions

ETHNOPHARMACOLOGICAL RELEVANCE

The fruits of Semecarpus anacardium L. f. (Anacardiaceae) are used in Ayurvedic medicine and also in Iranian Traditional Medicine for various indications, among those for retarding and treatment of dementia.

AIM OF THE STUDY

The severity of Alzheimer's disease obviously correlates with a cholinergic deficit. In a screening for acetylcholinesterase (AChE) inhibitory activity, an extract from the fruit resin of Semecarpus anacardium was among the most active ones. Thus, the aim of this study was to isolate the active compounds and to investigate them in detail. Their binding mode to the active site of AChE was investigated by in silico docking experiments.

MATERIALS AND METHODS

From a dichloromethane extract in an activity-guided fractionation the active compounds were isolated under use of different chromatographic techniques. Their structures were unambiguously identified by one and two-dimensional (1)H and (13)C NMR spectroscopy and mass spectrometry and their cholinesterase inhibitory activities were determined by a microplate assay. In order to compare the 3D active sites of AChE from Torpedo californica (TcAChE) and from Electrophorus electricus (EeAChE), three files from the Protein Data Bank (PDB) were used and for docking experiments, GOLD 3.1 software was employed. The concentrations of active compounds in the extract and the fruits were determined by HPLC analysis.

RESULTS

The active compounds were determined as 1',2'-dihydroxy-3'-pentadec-8-enylbenzene (A) and 1',2'-dihydroxy-3'-pentadeca-8,11-dienylbenzene (B). Their IC(50) values in an in vitro assay on AChE inhibition were determined as 12 and 34 μg/mL, respectively, while they were not active in the inhibition of butyrylcholinesterase (BChE). In silico docking experiments showed a similar bioactivity for compounds A and B. The concentration of compounds A and B in the fruits was 1.85% and 1.88%, respectively.

CONCLUSION

In the search for the active principle of the fruit resin of Semecarpus anacardium, compounds A and B were identified as two selective inhibitors for AChE versus BChE.