第二十届美国听力学年会报道(Ⅰ)——聆听永远 健康常驻

2008年4月2～5日,美国听力学年会在美国北卡罗莱纳州的夏洛特市召开。2008年恰逢美国听力学学会创建20周年,从最初32名听力学家倡导建会到现     

儿童变应性鼻炎舌下特异性免疫治疗的近期疗效观察

目的　观察舌下特异性免疫治疗（sublingual immunotherapy,SLIT）应用于治疗儿童变应性鼻炎的近期临床疗效。方法　采用前后自身对照,比较44例3～13岁尘螨过敏的变应性鼻炎患者治疗前及治疗3、6个月的症状评分、药物评分、视觉模拟量表（visual analogue scale,VAS）评分及血液嗜酸性粒细胞（eosinophil,Eos）水平,评价SLIT的近期临床疗效。结果　SLIT治疗3个月和6个月后,患者的鼻部症状评分、药物评分及VAS评分较治疗前显著下降,差异有统计学意义（P 均<0.05）;SLIT治疗3个月 与治疗6个月相比,患者鼻塞、流涕、喷嚏症状评分,鼻部总症状评分、药物评分及VAS评分相似,差异无统计学意义（P 均>0.05）,而鼻痒症状评分差异具统计学意义 （Z =-4.185,P <0.05）;SLIT治疗6个月与治疗前相比,血液Eos水平显著下降,差异具有统计学意义（Z=-4.544,P<0.05）。结论　舌下含服标准化粉尘螨滴剂是治疗尘螨变应性鼻炎儿童患者的一种安全有效的治疗方法,可在治疗3个月左右观察到疗效,SLIT治疗6个月后患者Eos百分比显著降低。     

Speech perception in noise: Masking and unmasking

Speech perception is essential for daily communication.Background noise or concurrent talkers,on the other hand,can make it challenging for listeners to track the target speech(i.e.,cocktail party problem).The present study reviews and compares existing findings on speech perception and unmasking in cocktail party listening environments in English and Mandarin Chinese.The review starts with an introduction section followed by related concepts of auditory masking.The next two sections review factors that release speech perception from masking in English and Mandarin Chinese,respectively.The last section presents an overall summary of the findings with comparisons between the two languages.Future research directions with respect to the difference in literature on the reviewed topic between the two languages are also discussed.     

北京地区中小学生常见吸入性变应原的调查分析

目的　了解北京地区中小学生中常见吸入性变应原的种类分布情况。方法　在北京地区参加调查的学生中,对其中1280名学生进行皮肤点刺试验,495名变应原阳性。结果　北京地区中小学生中有49.3%的人对4种及4种以上变应原呈阳性反应,对常年组和夏秋季花粉变应原均呈阳性的最为常见（37.4%）;城区中常见的前3位变应原为粉尘螨、屋尘螨、大籽嵩花粉;郊区为粉尘螨、柳树、大籽嵩花粉;按性别及年龄分组中,粉尘螨、屋尘螨、大籽嵩花粉为最常见的三类变应原,随年龄增长,阳性率降低。结论螨虫及夏秋季花粉是北京地区中小学生中最重要的变应原。     

"肾虚"对老龄豚鼠听觉功能影响的实验研究

目的研究“肾虚”对老龄豚鼠听觉器官形态及功能的影响。方法29只26月龄豚鼠，经ABR检测分为听阈异常的耳聋组和听阈正常的正常老龄组。正常老龄组又随机分为老龄组和造模组。造模组豚鼠制备“肾虚”模型。另取3月龄豚鼠8只作为正常对照组。比较各组豚鼠ABR反应阈、各波潜伏期以及耳蜗外毛细胞数量及“肾虚”相关指标差异，分析老龄豚鼠听功能变化与“肾虚”之间的关系。结果反映“肾虚”状态的各项检测值及“肾虚”总评分显示，造模组的“肾虚”最重，耳聋组其次，老龄组与3月龄组豚鼠在“肾虚”程度上差异无统计学意义。造模组听阈明显提高，ABR各波潜伏期延长，外毛细胞缺失明显（P〈0.01）。结论豚鼠在衰老过程中发生的听觉功能退化与“肾虚”状态有一定的相关性，“肾虚”状态加重时，听觉功能的退化也呈现相应的趋势。     

过敏性疾病免疫治疗国际共识（2015）解读

自2 0 世纪初期特异性过敏原免疫治疗（allergen-specific immunotherapy,ASIT）就已被用来治疗过敏性疾病。尽管大量的临床试验和Meta分析证明ASIT的有效性,但是ASIT仍然得不到广泛的应用。ASIT是唯一能够改变过敏性疾病自然病程的治疗措施,表现在能够预防哮喘的发生和新的过敏原致敏以及诱导机体对特异性过敏原的免疫耐受。因此,制定一个详细广泛的ASIT共识是非常重要的。本文通过对ASIT国际共识的解读,为临床医师采用免疫治疗过敏性疾病提供帮助。     

Exclusive endoscopic transcanal approach to lateral skull base lesions: Institutional experience of 3 cases

Introduction:Majority of petrous bone and lateral skull base pathologies are benign in nature.The complex anatomy usually warrants an extensive approach with associated morbidity.Case summary:Two cases of petrous bone cholesteatoma(1 congenital cholesteatoma with facial palsy and 1 acquired cholesteatoma)and a case of glomus tympanicum were treated with exclusive endoscopic transcanal approach.The cases of petrous cholesteatoma were addressed with trans-promontorial and infra-cochlear approaches.The mean operative time was approximately 140 min.No CSF otorrhoea was noticed in the post-operative period.The average period of hospital stay was 3.7 days.Conclusion:In the subset of cases with limited benign disease an endoscopic trans-canal approach is a better alternative to an external approach.It decreases operative time,blood loss,chance of meningitis,morbidity and hospital stay.The lack of depth perception is a major hurdle which can be come over by experience in endoscopic middle ear surgery.This approach can create direct access to cochlea/petrous apex/internal auditory canal(IAC)/Supra-geniculate ganglion region.     

中耳炎基础及临床研究诊治新进展国家继续教育项目通知

西安交通大学医学院第二附属医院(西北医院)耳鼻咽喉科头颈外科病院、陕西省康复学会听力康复委员会及西安交通大学医学院人体解剖与组织胚胎学系联合主办的第十期国家级继续医学教育项目中耳炎基础及临床研究诊治新进展[No:2011-07-01-114(国)]将于2011年7月26～31日在西安市举办。学习班     

小儿人工耳蜗植入术后调试结果的变化特点

目的 探讨人工耳蜗植入小儿开机一个月调试结果 的变化特点,为其编程调试提供指导和依据.方法 受试对象为使用澳大利亚Cochlear Nucleus 24型人工耳蜗系统的31例儿童.术后一个月起行系列的人工耳蜗编程调试,在调试中运用小儿行为测听法获得阈值(threshold level,TL)、舒适阈(comfortable level,CL)等参数,并将开机及开机后一个月所获得的数据进行比较分析.结果 开机与开机一个月时相比,TL降低而CL升高,其中高频段电极通道的TL下降幅度较低频段电极通道更大,而低频段电极通道的CL增高幅度较高频段大(P＜0.001).各次调试获得的TL及CL结果 均显示高频段通道的电流水平高而低频段通道的电流水平低(P＜0.001).开机时低频段动态范围(dynamic ranges,DR)最大,而开机一个月后高频段DR最大(P＜0.001).开机一个月后高、中、低3个频段电极通道的DR均较开机时大,其中高频段的DR改变较低频段更明显(P＜0.001).结论 人工耳蜗植入小儿开机后的一个月期间,其编程调试结果 变化显著,有必要对患儿进行多次调试.     

Expression of COX-2 and transcription factor CCAAT enhancer binding proteinβin refractory sinusitis with nasal polyps and its significance

Objective To study the expression and significance of COX-2 and C/EBP-βin refractory sinusitis with nasal polyps,and to explore the relationship between them and the recurrence of sinusitis with nasal polyps.Methods The protein expression of COX-2 and C/EBP-βin 20 cases of refractory sinusitis with nasal polyps,20 cases of sinusitis with nasal polyps and 20 cases of normal nasal mucosa were detected by western blot,and the relationship between the two was compared.Results The expression levels of COX-2 and C/EBP-βin refractory sinusitis with nasal polyps were significantly different from those in refractory sinusitis with nasal polyps(P<0.05);The expression levels of COX-2 and C/EBP-βin sinusitis tissues with nasal polyps were significantly different from those in normal nasal mucosa tissues(P<0.05);The expression levels of COX-2 and C/EBP-βin each group were significantly correlated(P<0.05).Conclusions The high expression of COX-2 and C/EBP-βmay be closely related to postoperative recurrence of sinusitis patients with nasal polyps.Both may be used as objective indicators to judge the postoperative follow-up and recurrence tendency of patients with sinusitis with nasal polyps..     

One‐stop neck lump clinic: phase 2 of audit. How are we doing?

One‐stop neck lump clinic: phase 2 of audit. How are we doing? Regular monitoring and audit of a service are integral to ensuring maintenance of efficiency and standards. This is particularly important where the quality of the service is operator dependent, as is the case in the clinical diagnosis of neck lumps and fine needle aspiration cytology. The one‐stop neck lump clinic has now been running in the department for more than 20 months. A previous article described the results of the first phase audit carried out at 6 months and had identified a waiting time to be seen that was longer than that recommended by the British Association of Otorhinolaryngologists, Head and Neck Surgeons. Measures were implemented to reduce this waiting time and a second audit was carried out after another 10 months with the aims of assessing if modification of the means of referral reduces waiting time and if the outcomes of clinical performance in phase 1 could be maintained or improved. We discuss the results of phase 2 in the audit spiral.     

A Decrease in Maxillary Sinus Pressure,as Seen in Upper Airway Allergy or Infection,Results in an Increase in Upper Airway Nitric Oxide Levels

The paranasal sinuses are connected to the nasal cavity via small osties. Ostial occlusion, caused by mucosal swelling, will result in a slowly increasing negative pressure inside the sinus cavity. In parallel, the oxygen content in the sinus will decrease, resulting in the development of relative hypoxia. Hypoxia is a powerful inducer of nitric oxide (NO) synthase, and inducible NO synthase has been shown to be present in considerable amounts in the upper airways, including the sinuses. The present study was designed to investigate whether a reduction in sinus pressure would affect upper airway NO production. Thirteen healthy volunteers were investigated. A pressure chamber was used to lower the ambient pressure to-4.9 kPa. NO was sampled from one nostril or via a drainage tube inserted into the maxillary sinus before, during and after the hypobaric exposure. When the pressure was decreased, NO levels increased from 256 &#45 15 to 316 &#45 19 ppb ( n =13, p <0.001). The NO levels remained elevated (282 &#45 21 ppb; p <0.05) when measurements were repeated 20 min after leaving the chamber. The nasal airway resistance (V2 tot ) also increased as a result of the chamber session (from 16 &#45 2° before to 21 &#45 3° after; p <0.05). An increase in NO levels was also found when the experiments were repeated with NO sampled directly from the maxillary sinus (225 &#45 6 before and 265 &#45 9 ppb after; n =6, p <0.001). For control purposes the nasal analyses were repeated again, this time under hyperbaric conditions (+4.9 kPa). This resulted in a slight decrease in the NO levels (from 273 &#45 22 to 241 &#45 17 ppb; n =10, p <0.001), but there was no change in the nasal airway resistance. We conclude that a reduction in sinus pressure, as seen in upper airway allergy or infection, may result in an increase in upper airway NO production.     

Physiologische Grundlagen einer Hörprothese

Zusammenfassung Im Bemühen, eine Hörprothese zu entwickeln, die ein Sprachverständnis erlaubt, erscheint es zumindest fürs erste am zweckmäßigsten, durch künstliche elektrische Reizung des Hörnerven die natürlichen Verhältnissen so gut als möglich zu imitieren. Der normale Hörnerv enthält etwa 30000 Nervenfasern, die sich qualitativ gleich, quantitativ jedoch unterschiedlich verhalten, wobei über die Eigenschaften der von den ÄHZ kommenden Spiralfasern im Augenblick sichere Aussagen nicht möglich sind (siehe 2.3). Die quantitativen Unterschiede zwischen den einzelnen Hörnervenfasern beziehen sich auf deren Frequenzabstimmung, Frequenzselektivität, Schwellen, Intensitätsfunktionen und — wichtig insbesondere für das Vorhaben einer künstlichen elektrischen Reizung — in Zeitunterschieden in den Aktivitätsmustern, die durch Laufzeitunterschiede auf der Basilarmembran bedingt sind (2.3). Diese Zeitunterschiede in der Aktivität einzelner Fasern liegen im Bereich mehrerer ms (2.3.6; 2.3.7). Die durch Schallreize im normalen Hörnerven ausgelösten Aktionspotentiale haben überdies einen probabilistischen Charakter, d. h. ihr Auftreten ist keineswegs streng determiniert. Es versteht sich von selbst, daß man bei künstlicher, elektrischer Reizung nicht alle verbliebenen Nervenfasern selektiv reizen kann. Somit wird eine Reizelektrode immer eine Gruppe von Nervenfasern erregen müssen. Bei jeder denkbaren elektrischen Reizung wären alle Fasern im Reizbereich einer Elektrode synchron und streng deterministisch aktiviert, was einen außerordentlich ernstzunehmenden Unterschied zu natürlichen Verhältnissen darstellt (3.2).Um die Zahl der zum Sprachverständnis mindestens notwendigen Reizkanäle abzuschätzen, wird man, in Ermangelung anderer experimenteller Daten, von psychoakustischen Untersuchungen an Normalhörenden auszugehen haben. Diese haben gezeigt, daß das Gehör neben einer außerordentlichen Fähigkeit verschiedene Tonhöhen zu unterscheiden, andererseits die Fähigkeit besitzt, bestimmte Frequenzgebiete zu sogenannten Frequenzgruppen zu integrieren. Die in eine solche Frequenzgruppe fallende Schallenergie wird zu einem einheitlichen Höreindruck verarbeitet. Es scheint also sinnvoll, die für einen Prothesenbau notwendige Zusammenfassung von Gruppen von Fasern des Hörnerven in verschiedene Reizkanäle entsprechend diesen Frequenzgruppen vorzunehmen (3.1). Demnach müßte der Sprachbereich in 15 Reizkanäle aufgeteilt werden, was wiederum, wenn man in der Cochlea reizen will, 1,2 mm Abstand von Kanal zu Kanal erlauben würde. Dabei müßte der Reizerfolg sauber auf die einzelnen Kanäle beschränkt bleiben, d.h. eine optimale Kanaltrennung erreicht werden. In Anbetracht der groben Abweichungen der neuronalen Aktivität vom normalen Verhalten, die bei künstlicher, elektrischer Reizung unvermeidlich sind, ist freilich unsicher, ob die angegebene Zahl ausreichen würde. Andererseits ist es in Anbetracht der zu erwartenden Stromverteilung im Sprachbereich kaum vorstellbar, mehr als die angegebene Zahl von Kanälen realisieren zu können.Was die Kodierung der Schallparameter innerhalb eines Elektrodenkanals betrifft, wird vorgeschlagen, die Frequenzkodierung nach dem Ortsprinzip optimal auszunutzen, und im Hinblick auf die Periodizitätsanalyse und die Lautheitskodierung sich soweit als möglich den natürlichen Verhältnissen anzunähern (3.3). Dabei wären Laufzeitunterschiede zwischen den Kanälen und der probabilistische Charakter der neuronalen Entladungen soweit als möglich einzuführen, um die Dominanz eines periodicity pitch zu vermeiden.Eine für Sprachverständnis ausreichende Prothese ist auch nur denkbar, wenn eine Prothese die zur Sprachübertragung notwendige Übertragungskapazität besitzt. Ergebnisse der Kanal-Vocoder-Technik zeigen, daß Sprache noch mit 1500 bit/s befriedigend übertragen werden kann. Eine Abschätzung der möglichen Leistungsfähigkeit einer 15-kanaligen Prothese (3.4), basierend auf der Zahl der möglichen unterscheidbaren Unterschiedsstufen der Hörempfindung, ergibt, daß diese Übertragungskapazität knapp erreicht werden könnte. Allerdings ist damit noch nicht gesagt, daß das Zentralnervensystem die angebotene Information auch im Sinne einer Phonemanalyse auswertet und damit für ein Sprachverständnis maximal ausschöpft. Nur für diesen Fall wäre ein Sprachverständnis zu erwarten.Als Reizort erscheint in erster Linie die Cochlea (5.1) geeignet. Für den Fall einer Degeneration der primären afferenten Fasern des Hörnerven ist aufgrund physiologischer Überlegungen auch der Nucleus cochlearis ventralis (5.5) interessant, allerdings würde so nur der ventrale Anteil der Hörbahn stimuliert. Doch besitzen auch andere Reizorte spezifische Vorteile (5.2–5.4).Theoretische Überlegungen (6.1) und experimentelle Messungen an implantierten Elektrodensätzen (6.3) zeigen, daß die Forderung der Kanaltrennung nur schwer zu erreichen sein wird. Deswegen wird der dynamische Bereich (im Hinblick auf Veränderung des Reizstromes) eines nach den obigen Kriterien konstruierten Reizkanals auf maximal 3 dB zu beschränken sein, so daß Erregungsausbreitung auf weitere Bereiche der Cochlea durch Ansteuerung von mehreren Reizkanälen zu imitieren wäre.Die Chancen, eine Prothese zu verwirklichen, die befriedigendes Sprachverständnis auf der Basis einer quasinatürlichen Reizung des Hörnerven erlaubt, wird von uns in Anbetracht der geschilderten mannigfaltigen Schwierigkeiten als sehr niedrig angesehen. In Anbetracht des großen Nutzens, der andererseits eventuell resultieren könnte, halten wir die Erforschung des Problems jedoch für angebracht.Es wird von uns vorgeschlagen, auch zu untersuchen, ob sich für eine prothetische Versorgung vorverarbeitete Sprache besser eignet (7.). Für Prothesen, die ein Sprachverständnis nicht anstreben, halten wir eine Implantation in die Cochlea für überflüssig. Hier erscheint uns die Implantation von Reizelektroden am runden Fenster (Douek et al., 1977; Fourcin et al., 1978; s. a. 1. und 7.) wegen des geringeren Risikos der überlegenere Weg.Die zitierten eigenen Arbeiten der Autoren wurden mit Unterstützung der DFG durchgeführt (DFG-K1 219).     

The expression of vascular endothelial growth factor (VEGF) and VEGF‐C in early laryngeal cancer: relationship with radioresistance

The expression of vascular endothelial growth factor (VEGF) and VEGF‐C in early laryngeal cancer: relationship with radioresistance Angiogenesis is essential for tumour growth and invasion. Vascular endothelial growth factor (VEGF) is a prime mediator of tumour angiogenesis. VEGF‐C is a closely related protein that effects lymphatic endothelial cells and may be important in the process of lymphatic metastasis. The purpose of this study was to evaluate the expression of these cytokines in patients with T1 and T2a glottic, squamous cell carcinoma, in comparison with normal epithelial control tissue, to ascertain any association with radioresistance. Twenty‐two tumours treated by radiotherapy (13 radiosensitive, nine radioresistant) and seven normal control tissues were studied. The minimum follow‐up was 2 years after radiotherapy. Expression of VEGF and VEGF‐C was evaluated by immunohistochemistry of formalin‐fixed, paraffin‐embedded biopsy specimens. Analysis was carried out using a quantitative computer image analyser. Both VEGF and VEGF‐C were detectable in tumour and normal control specimens. There was increased expression in tumour specimens of both VEGF (P = 0.03) and VEGF‐C (P < 0.001). In addition, the expression of VEGF‐C was associated with tumours of higher histological grade (P = 0.021). There was, however, no difference in VEGF and VEGF‐C expression between radioresistant and radiosensitive tumours. The expression of VEGF and VEGF‐C is increased in early laryngeal squamous cell carcinoma (SCC). However, measuring the expression of these proteins cannot predict radioresistance in this tumour group.     

Limited Surgery for Cancer of the Larynx and Hypopharynx: Options and Consequences

We reviewed surgical options for laryngeal preservation (limited surgery) in laryngeal and hypopharyngeal cancers and the consequences of the options. Of 44 patients with laryngeal cancer, 11 (25%) received limited surgery and 33 (75%) received total laryngectomy. The survival rates were 91% for the limited surgery group and 73% for the total (radical) surgery group. Of 31 patients with hypopharyngeal cancer, 7 (23%) received limited surgery and 24 (77%) received total laryngopharyngectomy. The survival rates were 53% for the limited surgery group and 40% for the total (radical) surgery group. The survival rates associated with limited surgery were thus better than those for total (radical) surgery for cancers of both the larynx and hypopharynx. This was attributed to the limited surgery group comprising well-selected patients with confined lesions. Organ preservation surgery should be technically simple, reliable in terms of its functional impact and, above all, should not jeopardize the patient's survival. Supracricoid subtotal laryngectomy with cricohyoidoepiglottopexy or cricohyoido-pexy has great potential for laryngeal preservation and will become the major limited surgery modality for treating cancer of the larynx. Limited surgery, however, needs to be performed with great care and is indicated only for very well-selected patients with cancer of the hypopharynx.     

Treatment of Maxillary Sinus Carcinoma: Clinical Results Using the Kitasato Modality

The conventional therapeutic regimen for maxillary sinus carcinoma consists of dissection of the maxilla, full-dose irradiation and extensive chemotherapy. However, the results obtained with this treatment are often poor. Even when patients recover, their quality of life is significantly reduced as a result of deformity of facial structures and swallowing and articulation dysfunctions. A retrospective analysis of 68 patients with maxillary sinus carcinoma treated with the Kitasato modality between 1975 and 1999 was conducted. All patients underwent pergingival maxillary sinus surgery combined with pre- and postoperative irradiation therapy with standardized total doses of 16 Gy; the postoperative irradiation was given in combination with regional intra-arterial infusion chemotherapy administered via the superficial temporal artery. All visible tumor lesions were removed where possible in order to preserve or facilitate cellular immunity after surgery. The cumulative 5-year survival rates were 85.7% for Stage II patients, 88.1% for Stage III, 76.6% for Stage IVA and 75.0% for Stage IVB.     

Cervical Reflex Induced by Click Stimuli in Cats

We studied click-evoked potentials in the anterior horn of the spinal cord in 17 cats. A concentric needle electrode was inserted into the anterior horn of the spinal cord at levels C3-C6. Potentials evoked with 105 dB SPL clicks were recorded with a peak latency of 4.89-5.10 ms only at the C3 level. These responses were observed 45-60 dB SPL above the auditory brainstem response (ABR) threshold, and no potentials were evoked by stimulation of the contralateral ear. Average was performed 100 times with changes in stimulation frequency of 1-20 Hz. The amplitude of the potentials decreased with increasing stimulus frequency, but there were no changes in ABRs. The responses disappeared after destruction of the medial vestibulospinal tract at the obex level, but ABRs were still recorded. The spinal nucleus of the accessory nerves was located in the anterior horn of the spinal cord at levels C1-C6, and the sternocleidomastoid muscle motoneurons were found at levels C1-C3. The click-evoked potentials recorded in this study reflect responses of the spinal nucleus of accessory nerves through the vestibulospinal tract to click stimulation. The responses have the same characteristics as vestibular-evoked myogenic potentials that can be recorded using surface electrodes over the sternocleidomastoid muscles of humans.     

Cochlear Function in Ears with Immunomediated Inner Ear Disorder

The aim of the present study was to evaluate the performance of ears with inner ear disorder, responsive to immunosuppressive drugs, in advanced tests designed to assess primary cochlear functions (temporal integration, frequency selectivity, cochlear mechanics). The results of this study suggest that immunomediated inner ear disease results, in the acute clinical stage, in the development of endolymphatic hydrops, which increases the stiffness of the vibrating structures within the inner ear and causes dysfunctions of the outer hair cells. Our patients presented with upsloping or flat sensorineural hearing loss, absence of evoked otoacoustic emissions and distortion-product otoacoustic evoked emissions and abnormal temporal integration, frequency selectivity and cochlear mechanics. Following immunosuppressive treatment, hydrops recovered, hearing subsequently returned to normal, the audiometric curve became flat at low-to-middle frequencies and primary cochlear function tended to normalize. This study seems to support the usefulness of testing primary cochlear functions in order to monitor the clinical course of immunomediated inner ear disorders.     

Bacterial Interference Between Pathogens in Otitis Media and Alpha-Haemolytic Streptococci Analysed in an In Vitro Model

Bacterial interference studied by means of agar methods has shown a decreased number of inhibitory alpha-haemolytic Streptococci among otitis-prone children. Additional information was gained regarding the interplay between alphahaemolytic Streptococci (AHS) and otitis media (OM) pathogens by comparing the bacterial interference in broth with the interference activity studied using agar overlay methods. We found that non-typeable Haemophilus influenzae (NTHI) and Moraxella catarrhalis are readily inhibited by AHS in broth. Streptococcus pneumoniae was more bacteriostatically inhibited. If two OM pathogens were inoculated simultaneously, an isolate of AHS with poor inhibitory activity was not able to inhibit the growth, in contrast to an isolate of AHS with good inhibitory activity. The initial amount of AHS inoculated with M. catarrhalis seemed to play a decisive role with respect to the inhibitory activity. M. catarrhalis developed reduced susceptibility against AHS both in vivo and in vitro . In vivo studies showed that children with secretory otitis media had fewer isolates of AHS in their nasopharynx with the ability to inhibit all the test pathogens than healthy children ( p < 0.001). Although the factor(s) responsible for the inhibitory activity have thus far not been defined, we could exclude low pH and nutrition depletion as the inhibitory mechanism of AHS with good inhibitory activity.     

Compound Action Potential and Cochlear Microphonic Extracted from Electrocochleographic Responses to Condensation or Rarefaction Clicks

In electrocochleography (ECochG) compound action potential (CAP) and summation potential (SP) are usually separated from the cochlear microphonic (CM) by the CM cancellation technique consisting in averaging the responses evoked by rarefaction and condensation clicks. With the aim of analysing the ECochG responses evoked by monophasic clicks, we developed a numerical method based on the theory of optimal filtering, which makes no assumptions about the unknown potentials. The application of the filtering technique to the ECochG recordings obtained from 6 normally hearing children and 10 children with cochlear hearing loss allowed us to perform CAP extraction in cases where CM was not cancelled by the conventional method. Differences in SP amplitude and polarity were found between rarefaction and condensation click-evoked responses in cochlear hearing losses.