Nestin-expressing cells are mitotically active in the mammalian inner ear

Nestin expression is associated with pluripotency. Growing evidence suggests nestin is involved in hair cell development. The objective of this study was to investigate the morphology and role of nestin-expressing cells residing in the early postnatal murine inner ear. A lineage-tracing nestin reporter mouse line was used to further characterize these cells. Their cochleae and vestibular organs were immunostained and whole-mounted for cell counting. We found Nestin-expressing cells present in low numbers throughout the inner ear. Three morphotypes were observed: bipolar, unipolar, and globular. Mitotic activity was noted in nestin-expressing cells in the cochlea, utricle, saccule, and crista. Nestin-expressing cell characteristics were then observed after hair cell ablation in two mouse models. First, a reporter model demonstrated nestin expression in a significantly higher proportion of hair cells after hair cell ablation than in control cochleae. However, in a lineage tracing nestin reporter mouse, none of the new hair cells which repopulated the organ of Corti after hair cell ablation expressed nestin, nor did the nestin-expressing cells change in morphotype. In conclusion, Nestin-expressing cells were identified in the cochlea and vestibular organs. After hair cell ablation, nestin-expressing cells did not react to the insult. However, a small number of nestin-expressing cells in all inner ear tissues exhibited mitotic activity, supporting progenitor cell potential, though perhaps not involved in hair cell regeneration.

Efficacy of Cochlear Implantation in Neurofibromatosis Type 2 Related Hearing Loss

OBJECTIVE

To investigate the results of cochlear implantation in subjects with neurofibromatosis type 2 (NF2) and bilateral vestibular schwannomas (VS).

STUDY DESIGN

Retrospective case series.

SETTING

University-based tertiary referral center.

SUBJECTS

Five subjects with NF2 and severe-to-profound sensorineural hearing loss.

INTERVENTION

Cochlear implantation.

MAIN OUTCOME MEASURE

Surgical outcomes and audiometric performance after cochlear implantation.

RESULTS

Five subjects (3 female, 2 male) were included in the study. The mean age at the time of implantation was 54 years old (range 35-78 years). Follow-up after cochlear implantation averaged 38 months (range 21-106 months). In the 5 implanted ears, 2 had no prior treatment, 1 had undergone prior radiation therapy, 1 underwent prior microsurgical removal, and 1 underwent prior microsurgical removal with adjuvant radiation therapy. The mean ipsilateral VS dimensions at time of implantation were 14 mm × 7.2 mm × 6.1 mm (mediolateral × anteroposterior × craniocaudal). Following cochlear implant activation, all 5 subjects achieved sound awareness, open set speech recognition, and 4 continue to be daily users of the devices.

CONCLUSION

Cochlear implantation is a viable hearing rehabilitation option for subjects with NF2 and severe-to-profound sensorineural hearing loss. All subjects reported benefit with their cochlear implant, including open set speech recognition, enhanced lip-reading skills and environmental awareness of sound. Four subjects continued to demonstrate improved open-set speech recognition at the time of their last evaluations.

Impact of vestibular nerve preservation on facial and hearing outcomes in small vestibular schwannoma surgery: a technical feasibility study

BACKGROUND

Management of small vestibular schwannomas (VSs) remains controversial. When surgery is chosen, the preservation of facial and cochlear nerve function is a priority. In this report, we introduce and evaluate a technique to anatomically preserve the vestibular nerves to minimize manipulation and preserve the function of the facial and cochlear nerves.

METHODS

The vestibular nerve preservation technique was prospectively applied to resect small VS tumors in patients with serviceable preoperative hearing (American Academy of Otolaryngology-Head and Neck Surgery (AAO-HNS) class A or B). Clinical and radiological data were recorded and analyzed.

RESULTS

Ten patients met the inclusion criteria. The mean (SD) age was 40.4 (12.5) years. Follow-up ranged from 6 weeks to 2 years. The maximum tumor diameter parallel to the internal auditory canal ranged from 10 to 20 mm (mean, 14.9 (3.1) mm). There were three Koos grade 3 and seven Koos grade 2 tumors. Gross total resection was achieved in all cases. Both the facial and cochlear nerves were anatomically preserved in all cases. Postoperatively, 7 patients (70%) remained in the AAO-HNS class A or B hearing category. None of the patients had new vestibular symptoms, and all had House-Brackmann grade 1 facial function. Nervus intermedius dysfunction was observed in 1 patient preoperatively, which worsened postoperatively. Two patients had new nervus intermedius symptoms postoperatively.

CONCLUSION

Improvement of facial nerve and hearing outcomes is feasible through the intentional preservation of the vestibular nerves in the resection of small VSs. Longer follow-up is required to rule out tumor recurrence.

The Combined Endoscopic Endonasal Far Medial and Open Postauricular Transtemporal Approaches As a Lesser Invasive Approach to the Jugular Foramen: Anatomic Morphometric Study With Case Illustration

BACKGROUND

Access to the jugular foramen (JF) requires extensive approaches. An endoscopic endonasal far medial (EEFM) approach combined with a postauricular transtemporal (PTT) approach may provide adequate exposure with limited morbidities.

OBJECTIVE

To provide a quantitative anatomic comparison of the EEFM, the PTT, and the combined EEFM/PTT approaches. A clinical case of the combined approach is presented.

METHODS

Five cadaveric heads were dissected. Each specimen received PTT and EEFM approaches on opposite sides followed by an EEFM approach on the side of the PTT approach. Morphometric and quadrant analyses were conducted. Three groups were obtained and compared: PTT (group A), EEFM (group B), and combined (group C).

RESULTS

Group B had a significantly higher area of exposure of the JF as compared to group A (112.3 and 225 mm2, respectively, P = .004). The average degree of freedom (DOF) in the cranio-caudal plane for groups A and B was 63.6 and 12.6 degrees, respectively (P < .00001). Group A had a higher DOF in the medial-lateral plane than group B (49 vs 13.4 degrees, respectively, P < .00001. The average volume of exposure in groups A and B was 1469.2 and 1897.4 mm3, respectively (P = .02). By adding an EEFM approach to the PTT approach, an additional 56.1% of the anterior quadrant was exposed, representing a 584.4% increase in the anterior exposure.

CONCLUSION

The PTT and EEFM approaches provide optimal exposures to different aspects of the JF and in combination may constitute a less invasive alternative to the more extensive approaches.

Do Patients Benefit From a Cochlear Implant When They Qualify Only in the Presence of Background Noise?

OBJECTIVE

To compare the difference in pre- to postoperative speech performance of patients qualifying for a cochlear implant (CI) in quiet, +10 dB signal-to-noise ratio (SNR), and +5 dB SNR.

STUDY DESIGN

Retrospective.

SETTING

Tertiary referral center.

PATIENTS

Fifty-eight post-lingually deafened, unilateral CI recipients from three Groups were included: 1) those who met CI candidacy criteria with AzBio sentences in quiet, 2) in noise at +10 dB SNR but not in quiet, 3) and in noise at +5 dB SNR but not in quiet or +10 dB SNR.

INTERVENTION

Unilateral CI.

MAIN OUTCOME MEASURES

Pre- and 1 year postoperative speech recognition scores.

RESULTS

Best-aided AzBio speech recognition of individuals in Group 1 improved significantly for all test conditions and improved significantly for Groups 2 and 3 in the +10 and +5 dB SNR test conditions postoperatively. When tested with their CI alone however, while AzBio speech recognition of individuals in Group 1 and Group 2 improved significantly in the quiet and +10 dB SNR conditions, speech recognition was not significantly changed postoperatively under any testing condition for individuals in Group 3.

CONCLUSIONS

While individuals qualifying for a CI only in the +5 dB SNR condition may derive significant benefit from implantation in best aided conditions, speech understanding outcomes can be more variable thus warranting additional counseling before implantation and case-by-case consideration of listening needs and goals.

Presigmoid Approach to Dumbbell Trigeminal Schwannoma

This case is a 15-year-old male, presenting with headaches, right face, and arm numbness, and ataxia. MRI (magnetic resonance imaging) revealed a large right sided dumbbell shaped lesion, extending into the middle and posterior fossa with compression of the brainstem consistent with a trigeminal schwannoma. Treatment options here would be a retrosigmoid suprameatal approach or a lateral presigmoid approach. Given the tumor extension into multiple compartments, a presigmoid craniotomy, combining a middle fossa approach with anterior petrosectomy, and retrolabyrinthine approach with posterior petrosectomy were used to maximize the direct access corridor for resection. The petrous apex was already expanded and remodeled by the tumor. Nerve fascicles preservation technique is paramount to the functional preservation of the trigeminal nerve. The extent of resection should be weighed against the anatomical functional integrity of the nerve. Near total resection is considered if that means more nerve preservation. Postoperatively, the patient had a slight (House–Brackman grade II) facial droop, which resolved over days and developed right trigeminal hypesthesia at several weeks. This case is presented to demonstrate a combined petrosectomy technique for resection of lesions extending into both the middle and posterior cranial fossa with near total resection and trigeminal nerve preservation.

The link to the video can be found at: https://youtu.be/kA9GyFhL1dg.

Burden and characteristics of influenza A and B in Danish intensive care units during the 2009/10 and 2010/11 influenza seasons

Influenza surveillance in Danish intensive care units (ICUs) was performed during the 2009/10 and 2010/11 influenza seasons to monitor the burden on ICUs. All 44 Danish ICUs reported aggregate data for incidence and point prevalence, and case-based demographical and clinical parameters. Additional data on microbiological testing, vaccination and death were obtained from national registers. Ninety-six patients with influenza A(H1N1)pdm09 were recorded in 2009/10; 106 with influenza A and 42 with influenza B in 2010/11. The mean age of influenza A patients was higher in 2010/11 than in 2009/10, 53 vs. 44 years (P = 0·004). No differences in other demographic and clinical parameters were detected between influenza A and B patients. In conclusion, the number of patients with severe influenza was higher in Denmark during the 2010/11 than the 2009/10 season with a shift towards older age groups in influenza A patients. Influenza B caused severe illness and needs consideration in clinical and public health policy.

Low vaccine effectiveness against influenza A(H3N2) virus among elderly people in Denmark in 2012/13 – a rapid epidemiological and virological assessment

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Low vaccine effectiveness against influenza A(H3N2) virus among elderly people in Denmark in 2012/13--a rapid epidemiological and virological assessment

In Denmark, the 2012/13 influenza season has been dominated by influenza A(H3N2). We estimated the vaccine effectiveness (VE) of the trivalent influenza vaccine by linking national registers in a test-negative case-control study of patients tested for influenza aged ≥65 years. The adjusted VE against laboratory-confirmed influenza A and B was -11% (95% CI: -41 to 14) and 69% (95% CI: 26 to 87), respectively. Genetic characterisation of the influenza A(H3N2) viruses indicated genetic drift, with seven substitutions at key antigenic sites.

Description and analysis of 12 years of surveillance for Creutzfeldt–Jakob disease in Denmark, 1997 to 2008

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Description and analysis of 12 years of surveillance for Creutzfeldt-Jakob disease in Denmark, 1997 to 2008

Prospective surveillance of Creutzfeldt–Jakob disease (CJD) was initiated in Denmark in 1997, following the observation of variant CJD in the United Kingdom. Demographic, clinical and diagnostic information was collected for each patient with clinical suspicion of CJD. Here we describe the methods for surveillance and the observed outcomes between 1 January 1997 and 31 December 2008. A total of 83 patients were classified as sporadic CJD, 47 were definite diagnoses, 34 probable and two possible. This resulted in a mean incidence of 1.26 patients with probable and definite sporadic CJD per million inhabitants. Two sporadic CJD patients were found to have a genetic variant of unknown significance: Thr201Ser and Glu200Asp. One patient was diagnosed with Gerstmann-Sträussler-Scheinker syndrome. No patients were classified as having variant, iatrogenic or familial CJD. The Danish surveillance system, like those in other countries, has a multidisciplinary approach, which is labour-intensive and time-consuming but ensures the most complete set of information possible. With this approach we think that patients with variant CJD would have been detected had they occurred in Denmark. Certain aspects of CJD surveillance need further discussion at European level and beyond, in order to find a balance between efficiency of the systems and accuracy of surveillance data.

National surveillance of pandemic influenza A(H1N1) infection-related admissions to intensive care units during the 2009-10 winter peak in Denmark: two complementary approaches

Surveillance of 2009 pandemic influenza A(H1N1) in Denmark was enhanced during the 2009–10 winter season with a system monitoring the burden of the pandemic on intensive care units (ICUs), in order to inform policymakers and detect shortages in ICUs in a timely manner. Between week 46 of 2009 and week 11 of 2010, all 36 relevant Danish ICUs reported in two ways: aggregate data were reported online and case-based data on paper. Cases to be reported were defined as patients admitted to an ICU with laboratory-confirmed 2009 pandemic influenza A(H1N1) infection or clinically suspected illness after close contact with a laboratory-confirmed case. Aggregate numbers of cases were reported weekly: during weeks 48-51 (the peak), reporting was daily. The case-based reports contained demographic and clinical information. The aggregate surveillance registered 93 new cases, the case-based surveillance 61, of whom 53 were laboratory confirmed. The proportion of beds used for influenza patients did not exceed 4.5% of the national capacity. Hospitals with cases used a median of 11% of bed capacity (range: 3–40%). Of the patients for whom information was available, 15 of 48 patients developed renal insufficiency, 19 of 50 developed septic shock and 17 of 53 died. The number of patients with pandemic influenza could be managed within the national bed capacity, although the impact on some ICUs was substantial. The combination of both reporting methods (collecting aggregate and case-based data) proved to be useful for monitoring the burden of the pandemic on ICUs.

Positron Emission Tomography Scan to Determine the Need for Neck Dissection after Chemoradiation for Head and Neck Cancer: Timing is Everything

We present a case of a negative positron emission tomography (PET) scan in a patient with pathologic viable cancer at neck dissection.

STUDY DESIGN

Case Report.

METHODS

A 69-year-old man presented with clinical stage T2N2c squamous cell cancer of the left tonsil and was treated with definitive chemoradiation. Left-sided adenopathy decreased but remained palpable after therapy.

RESULTS

PET scan performed 23 days after completion of treatment showed no suspicious uptake in the left neck. Neck dissection performed at 2 months post-therapy revealed viable tumor in left cervical nodes.

CONCLUSIONS

Persistent adenopathy after chemoradiation for head and neck cancer remains a clinical dilemma. A negative PET scan is accurate but only if the scan is performed 3 to 4 months after therapy.

Expression of fibroblast growth factor receptors (FGFR1, FGFR2, FGFR3) in the developing head and face

Fibroblast growth factors may play an important role in the differential growth of the skull, brain, and facial prominences. In order to understand the role of FGFs in vivo, we have analyzed the competency of head mesenchyme to respond to FGFs via expression of the high affinity receptors FGFR1, 2, and 3. Receptor transcripts, especially those of FGFR2 and FGFR3, were localized to specific regions of the head. We raise the possibilities of particular receptor-ligand combinations and the possible functions of these interactions in the morphogenesis of the head, face, and brain. Finally, we discuss the relationship between FGF receptor expression in the chicken and the phenotypes of FGF receptor mutations in humans.