溶酶体神经氨酸酶基因缺乏小鼠听觉和耳形态学改变初步研究

目的研究溶酶体神经氨酸酶基因（Neul）敲除小鼠听功能和耳形态学改变，探讨唾液酸沉积症听力损害的病理生理机制。方法应用听性脑干反应测试和常规颞骨连续切片观察3周、2个月和4个月龄的Neul敲除纯合子（Neul-／-）和野生型（Neul＋／＋）小鼠听阈和光镜下外耳、中耳及内耳形态。结果3周龄的Neul-／-小鼠，短声和短音8、16及32kHz听阈（声压级）较Neul＋／＋提高50—55dB；2个月和4个月龄小鼠听阈提高60—68dB。Neul-／-小鼠3周龄即有明显的中耳和内耳改变，特别是2个月和4个月龄有显著的外耳道堵塞和严重中耳炎，听小骨和耳蜗骨壁细胞、血管纹边缘层和中间层细胞、耳蜗螺旋神经节细胞、螺旋缘纤维细胞、前庭膜、基底膜及沿前庭阶外淋巴隙的间皮细胞明显囊泡化，但Corti器细胞正常。前庭神经节细胞、壶腹嵴及球囊毛细胞和支持细胞也呈现明显囊泡化。结论溶酶体神经氨酸酶的缺乏可导致较严重的听力损害和耳形态改变；外耳道阻塞或中耳炎和听骨改变可能引起传导性聋；耳蜗螺旋神经元、血管纹、螺旋缘、前庭膜和基底膜等细胞的溶酶体储积可能导致感音神经性聋。     

组织工程化缓释骨形态发生蛋白2听骨赝复物听泡植入对豚鼠耳蜗功能的影响

目的 制备含缓释骨形态发生蛋白2(bone morphogenetic protein 2,BMP-2)的组织工程化听骨赝复物,植入豚鼠听泡内,观察其成骨诱导情况及对耳蜗功能的影响.方法 制备脱细胞骨微管,管腔内填塞含BMP-2胶原海绵,形成小柱状听骨赝复物.耳后人路植入豚鼠听泡,对侧耳植入不含BMP-2的赝复物作为对照.植入后不同时间点进行听性脑干反应(ABR)检测,观察听骨赝复物植入对豚鼠反应阈的影响.植入3个月后通过听泡组织切片及基底膜铺片,观察植入物成骨情况以及对听泡、耳蜗大体结构和毛细胞形态的影响.结果 术后动物健康状况良好.植入听骨赝复物即刻,ABR反应阈(声压级,x±s,下同)与术前[(15.5±2.8)dB]相比略有升高[(28.3±4.8)dB,P<0.05],3个月后已恢复正常[(16.1±4.0)dB,P>0.05].术后3个月,大体观察见植入的听骨赝复物被覆黏膜,耳蜗及听泡大体形态正常.组织学检查可见含缓释BMP-2的骨微管内壁有新骨形成,未见耳蜗及听泡骨质异常增生,镫骨底板与前庭窗周围骨质无融合.基底膜铺片硝酸银染色示毛细胞形态正常,未见缺失.结论 含缓释BMP-2的组织工程化听骨赝复物植入听泡后,可诱导新生骨形成,但对听泡及耳蜗形态结构无影响,不会引起周围骨质的异常增生,同时对ABR反应阈无影响.该方法有希望应用于听骨链缺损的修复重建.     

小鼠耳蜗Na-K-2Cl联合转运子-1的定位及其缺失后的耳蜗组织学改变

目的探讨耳蜗钾循环途径中Na-K-2Cl联合转运子-1(Na-K-2Clcotransporter-1,NKCC1)在小鼠耳蜗的分布及NKCC1基因敲除后耳蜗组织学的改变。方法选用10只C57BL/6J小鼠((NCKK1 / )和5只NKCC1基因敲除小鼠(NKCC1-/-),应用听性脑干反应(auditorybrainstemresponse,ABR)分别检测NCKK1 / 小鼠和NKCC1-/-小鼠的听功能,采用免疫组织化学及甲苯胺蓝染色的方法观察NKCC1在NCKK1 / 小鼠耳蜗的定位及NKCC1-/-小鼠耳蜗组织学的变化。结果NCKK1 / 小鼠ABR平均阈值为31±5.36dBSPL,而NKCC1-/-小鼠听力完全丧失。NKCC1在NCKK1 / 型小鼠耳蜗主要分布在血管纹上皮(边缘细胞)和螺旋韧带下部纤维细胞,在纹上区和螺旋缘处的纤维细胞中也有适度表达;NKCC1-/-小鼠耳蜗前庭膜塌陷,中阶完全消失,内毛细胞、外毛细胞、支持细胞减少,Corti隧道消失。结论NKCC1在耳蜗的定位与耳蜗钾循环密切相关,NKCC1缺失会导致耳蜗正常结构的破坏,继而影响耳蜗生理功能。     

高脂血症小鼠模型耳蜗中核因子-κB p65的表达

目的:探讨高脂血症对小鼠耳蜗的影响。方法:20只昆明种小鼠随机平均分为2组,其中1组建立高脂血症模型,另1组作为对照,6周后用多克隆兔抗NF-κB p65免疫组织化学染色,观察NF-κB p65在高脂血症小鼠耳蜗中的表达,并检测小鼠ABR反应阈。结果:在高脂血症小鼠耳蜗中,NF-κB p65主要定位在Corti器、盖膜、血管纹、螺旋韧带、螺旋神经节及其神经纤维,高脂血症小鼠耳蜗NF-κB p65的免疫反应与对照组比较显著增强。高脂血症模型组小鼠ABR反应阈与对照组比较明显增高,差异有统计学意义(P<0.01)。结论:高脂血症可使小鼠耳蜗NF-κB p65表达增强,ABR反应阈增高,表明高脂血症可引起小鼠听力损害。     

X-连锁低磷酸盐血症Pug小鼠的听力学和耳形态学研究

目的Phex基因点突变Pug小鼠是典型的人类X-连锁低磷酸盐血症小鼠模型。通过研究Pug小鼠的听力学表型,探讨Phex基因点突变对小鼠听觉功能与内耳形态的影响。方法运用听性脑干诱发电位（ABR）对4月龄Pug小鼠和野生型小鼠进行听功能测试,取小鼠耳蜗进行大体形态观察,运用石蜡切片观察小鼠耳蜗骨壁、前庭膜、血管纹、螺旋韧带、盖膜、Corti器、螺旋神经节等结构。运用扫描电镜观察小鼠耳蜗Corti器上的内、外毛细胞及其表皮板等结构。结果Pug小鼠的ABR在短声和8kHz、16kHz、32kHz短纯音刺激的反应阈值均有提高,在短声和16kHz、32kHz频率,其差异具有统计学意义（P〈0.05）。小鼠耳蜗骨壁增厚,骨质过度增长,有大量骨质矿化不完全区域;耳蜗底转部位螺旋神经节出现明显退化,神经元数目大量减少;耳蜗顶转到底转内、外毛细胞静纤毛散在性缺失,静纤毛形态异常。结论Phex基因点突变引起的基因功能缺失导致了Pug小鼠的听觉功能减退和耳蜗形态异常。     

晚期糖基化终产物受体在小鼠耳蜗中表达的初步探讨

目的通过研究晚期糖基化终产物受体(RAGE)在小鼠耳蜗中的表达,初步探讨RAGE与老年性聋关系。方法将C57BL/6J小鼠分为2月龄、10月龄组,分别行ABR阈值检测,组织学切片观察耳蜗形态结构,免疫组化和realtime PCR检测RAGE在耳蜗中的定位和定量表达,半定量RT-PCR检测其配体S100B在耳蜗中的表达情况。结果 :(1)10月龄小鼠较2月龄ABR阈值明显提高;(2)RAGE主要在两组小鼠耳蜗的螺旋神经节细胞,内外毛细胞和血管纹中表达,10月龄C57BL/6J小鼠耳蜗中RAGE平均光密度值比2月龄小鼠大,两组间差异有统计学意义;(3)2月龄组耳蜗中RAGE相对表达量为1±0.15,10月龄组小鼠耳蜗中RAGE相对表达量为2.0816±0.117,两组间差异有统计学意义;(4)配体S100B在10月龄小鼠耳蜗中表达增高。结论 RAGE在C57BL/6J小鼠耳蜗中有表达且随年龄增大表达增强,可能与配体S100B相互作用导致听力下降,提示RAGE可能与老年性聋的发病机制有关。     

噪声对耳蜗边缘细胞及螺旋神经节细胞乙酰化组蛋白H2B的影响

目的　观察噪声性聋豚鼠耳蜗侧壁血管纹边缘细胞及蜗轴螺旋神经节细胞乙酰化组蛋白H2B表达水平的变化。方法　成年雄性白色红目豚鼠50只随机分为噪声组和对照组,通过听性脑干反应检测两组豚鼠噪声前听力,噪声组给予高强度窄带噪声（122 dB SPL,3 h）暴露,于暴露后1 h行ABR检测噪声后听力,并通过免疫荧 光染色和Western blot方法检测暴露后2 h两组豚鼠耳蜗血管纹边缘细胞及蜗轴螺旋神经节细胞中乙酰化组蛋白H2B的表达水平。结果　两组豚鼠噪声暴露前听力在4、8、16与32 kHz频率的反应阈比较,差异无统计学意义。噪声组在噪声刺激1 h后ABR阈值在4、8、16与32 kHz频率的最大输出90 dB无反应。免疫荧光染色显示在噪声刺激2 h后血管纹边缘细胞中乙酰化组蛋白H2B荧光强度明显下降,Western blot显示噪声组豚鼠侧壁中乙酰化组蛋白H2B表达（H2B-AcK5/β-actin的比值为0.3471±0.0843）较对照组（0.6114±0.0207）明显下调,两组比较差异有统计学意义（t =5.268,P＜0.01）。耳蜗蜗轴组织中乙酰化组蛋白H2B表达在噪声组和对照组中分别为（0.4993±0.0994）和（0.5139±0.0132）,两组比较差异无统计学意义（P ＞0.05）。结论　噪声可导致豚鼠耳蜗血管纹边缘细胞组蛋白乙酰化水平显著下降,螺旋神经节细胞中组蛋白乙酰化水平无明显改变,血管纹边缘细胞组蛋白乙酰化失衡有可能参与噪声性聋的发生发展。     

KCNQ1在小鼠耳蜗血管纹的表达及在听觉中的意义

目的探讨KCNQ1在耳蜗侧壁血管纹的表达及其在听觉中的作用。方法以不同基因型小鼠KC-NQ1-/-(突变纯合子)、KCNQ1 /-(杂合子)和KCNQ1 / (野生型)以及C57BL/6J小鼠为实验对象,采用免疫组织化学和ABR检测技术,检测KCNQ1在小鼠耳蜗血管纹的表达及其听力。结果KCNQ1蛋白阳性颗粒集中在小鼠耳蜗血管纹边缘细胞顶膜。KCNQ1 / 小鼠的听力正常,短声ABR的阈值为36.67±7.13dBSPL;KCNQ1 /-小鼠听力低于同窝KCNQ1 / 野生型鼠,短声ABR的阈值为38.25±9.35dB SPL;KCNQ1-/-小鼠呈现全聋,ABR在100dB SPL时仍无反应。结论KCNQ1是位于耳蜗侧壁血管纹边缘细胞的重要通道蛋白,在维系耳蜗听觉功能中有重要作用。KCNQ1通道蛋白的缺失或功能受限可以不同程度地影响耳蜗的听觉功能。     

耳蜗半薄切片细胞凋亡检测

目的尝试在耳蜗半薄切片上用TUNEL方法检测耳蜗组织的细胞凋亡.方法基因敲除Smad5小鼠耳蜗,分别作常规石蜡切片和环氧树脂包埋的半薄切片,用TUNEL方法检测耳蜗组织的细胞凋亡.结果在半薄切片上Smad5基因敲除小鼠,耳蜗内有大量的凋亡细胞产生,主要集中在螺旋神经节细胞、血管纹上的细胞,以及基底膜上的间皮细胞等,而且能够更清楚的显示凋亡的毛细胞.而在石蜡切片上只在螺旋神经节细胞、血管纹上的细胞,以及基底膜上的间皮细胞检出凋亡细胞,但是毛细胞没有凋亡细胞的检出.结论用TUNEL方法检测耳蜗组织的细胞凋亡半薄切片明显好于石蜡切片.     

缝隙连接蛋白connexin 26基因条件性敲除小鼠血管纹超微形态研究

目的观察不同年龄缝隙连接蛋白26(Connexin 26,Cx26)基因条件性敲除小鼠血管纹的超微病理形态学改变,探索Cx26突变的致聋机制。方法将Cx26 loxP/loxP与foxg1-cre转基因小鼠进行杂交,获得Cx26条件基因敲除小鼠模型(Foxg1-Cre cCx26ko条件性敲除小鼠,简称为cCx26ko小鼠),与野生型小鼠(wild type,WT)进行对比。分离出小鼠耳蜗标本,先制作半薄切片定位,再行超薄切片,采用透射电子显微镜(transmission electron microscope,TEM)观察血管纹细胞的超微病理改变。结果血管纹各种细胞在早期未见异常;出生后120天(postnatal day 120,P120)起细胞内出现溶酶体增多,P180天见巨大吞噬细胞,P360天见色素颗粒。结论 Connexin 26基因条件性敲除小鼠出生后早期血管纹超微形态基本正常。成年转基因动物的血管纹出现超微病理学改变,推测其与细胞异常代谢和衰老有关,这可能是Cx26突变致聋的病理机制之一。     

Effect of uvulopalatopharyngoplasty (UPPP) on atherosclerosis and cardiac functioning in obstructive sleep apnea patients

Abstract

Background: Obstructive sleep apnea (OSA) is associated with several cardiovascular comorbidities including hypertension, arteriosclerosis, and heart failure. Uvulopalatopharyngoplasty (UPPP) is a frequently performed surgical treatment for OSA.

Aims/Objectives: To analyze if UPPP can improve cardiac parameters associated with atherosclerosis and reduce the cardiac burden in OSA patients.

Material and methods: A prospective cohort study was performed at a single tertiary care center where OSA patients undergoing UPPP were evaluated. Preoperative and 6-month postoperative cardiac parameters namely carotid artery intima-media thickness (CIMT), arterial stiffness parameters, echocardiography, and polysomnography (PSG) results were compared.

Results: Fifty three patients were included in the study. The success and response rate of UPPP was 60.4%. Following the surgery, significant reduction in arterial stiffness index (β) (12.4?±?4.1 vs. 11.2?±?4.0, p?=?.01), and elasticity modulus (Ep) (172.8?±?68.3 vs. 156.6?±?55.3, p?=?.05) was noticed. Additionally, echocardiographic parameters namely velocity across aortic valve (121.9?±?22.9 vs. 109.4?±?17.7, p?=?.01) and velocity across pulmonary valve (107.4?±?16.4 vs. 94.2?±?16.9, p?<?.01) significantly decreased following UPPP.

Conclusions and significance: UPPP significantly improves parameters related to carotid atherosclerosis and has the potential to reduce cardiac burden in OSA patients.     

Laryngeal Electromyography in the Management of Vocal Cord Mobility Problems in Children

Objectives To evaluate the efficacy and clinical usefulness of laryngeal electromyography (EMG) in the evaluation and management of vocal cord mobility problems in children; and to determine the ability of laryngeal EMG to differentiate vocal fold fixation versus paralysis. Study Design Case‐series review of 8 children with vocal cord immobility who underwent laryngeal EMG. Methods Eight children with bilateral vocal fold immobility underwent microlaryngoscopy and electromyography. Bipolar concentric needle electrodes were used and implanted separately into both posterior cricoarytenoid (PCA) and both thyroarytenoid (TA) muscles. EMG activity was recorded during spontaneous ventilation under a light plane of anesthesia with propofol. EMG activity was correlated with the phases of the respiratory cycle. Results Three patients had evidence of normal EMG activity with PCA activity peaking during early inspiration. Maximal TA activity occurred expiration. These patients were assumed to have vocal fold fixation. Two of these 3 patients underwent laryngotracheoplasty (LTP) with posterior glottic expansion with costal cartilage. One is being considered for LTP in the future. Five patients had abnormal EMG activity and remain tracheotomy‐dependent. Four patients exhibited synkinetic activity with peak PCA activity during expiration and peak TA activity during expiration. Two patients had both fixation and unilateral vocal cord paralysis. One was successfully decannulated after posterior graft LTP and the other is planned for the future. Conclusions Electromyography, which differentiates paralysis from fixation, is a useful diagnostic tool in the evaluation of children with vocal cord immobility.     

鼓室硬化和非鼓室硬化中耳炎抗氧化能力的差异性研究

目的 了解鼓室硬化和非鼓室硬化中耳炎患者在抗氧化物质超氧化物歧化酶(superoxide dismutase,SOD)、过氧化氢酶(catalnse,CAT)活性及过氧化反应产物丙二醛(malondialdehyde,MDA)浓度方面的差异,以进一步探讨鼓室硬化形成的机制.方法 回顾分析56例(56耳)中耳炎、中耳炎后遗症手术患者资料,分成两组:鼓室硬化组26耳,非鼓室硬化组30耳.测定所有患者血浆、红细胞中SOD、CAT活力及血浆、中耳组织中MDA浓度.结果 分析用秩和检验及相关分析.结果 两组血浆中MDA含量差异无统计学意义.鼓室硬化组中耳组织中MDA含量较高,差异有统计学意义(P<0.05).两组红细胞中SOD和CAT活力差异无统计学意义.鼓室硬化组血浆中的SOD和CAT活力较非鼓室硬化组低.差异有统计学意义.鼓室硬化组术前的听力平均值与其各检测项目所测得的MDA、SOD、CAT值均不存在相关(P>0.05).结论 鼓室硬化患者可能存在局部氧自由基浓度增高和抗氧化物质活性降低的情况.局部氧自由基浓度增高,血液抗氧化物质无法进入中耳组织,可能是形成鼓室硬化的病理基础.     

Random Gap Detection Test and Random Gap Detection Test-Expanded results in children with auditory neuropathy

Objectives

In auditory neuropathy (AN) children with hearing aids (HAs) or cochlear implant (CI), the speech perception improvement may not be in a significant degree. These children may perform speech perception after a few repeats. This condition may show that these children had difficulties in receiving and processing speech sounds. If the children with AN cannot distinguish the heard tones one or two in Random Gap Detection Test (RGDT), their benefit performances between hearing aids or CI may not be significant. It is thought that the answer of this question is closely related with unique auditory processing performance of each child. The aim of the study is to investigate the RGDT and RGDT-Expanded (RGDT-EXP) performance of five children with AN.

Methods

In this study, RGDT was applied to five children with auditory neuropathy between ages of 7 and 13 years (study group) (3 male, 2 female). As a control group, RGDT was applied to 10 normal hearing children who had not auditory processing problem between ages of 7 and 16 years (5 male, 5 female). In the first test, all children were applied to RGDT and RGDT-EXP. Each child responded whether he/she heard one or two tones. Their responses were taken as verbally and/or hold up one finger or two fingers. In the second test, they were applied speech discrimination test in quiet environment and in noise. Gap detection thresholds (GDTs) were detected at 500-4000 Hz; and composite GDTs (CGDTs) were found for the study and control groups. GDT/CGDT >20 ms was considered as abnormal for temporal processing disorder.

Results

Any of the children with AN who has no HAs; with HAs; and CI, could not be able to perform RGDT. Therefore the RGDT-EXP was applied in this group. In the study group, GDTs was all over 50 ms at 500-4000 Hz; and CGDTs were all over 50 ms for all children included into the study group with AN. In control group, except child 9 (GDTs were 25 ms at 3000 and 4000 Hz); and child 10 (GDT was 25 ms at 500 Hz); GDTs were all in normal limits for 500-4000 Hz for all children included into the study as control group. CGDTs were all in normal limits for the control group, except child 9 (CGDTs were 22.50, slightly higher than normal limits). In the study group with AN, mean of the GDTs was all over the normal limits; and in control group, mean of GDTs were all in normal limits. The difference between the mean GDTs of the study group was significantly higher than the control groups at all frequencies of 500-4000. In AN group, CGDT (97.5 ± 9.57 ms) was significantly higher than that of the control group (10.35 ± 0.65 ms).

Conclusion

We concluded that these results may only not be explained by auditory processing performance or temporal aspects of audition of each child. Their gap detection was much worse for short duration stimuli than for longer duration stimuli. The present study showed that temporal processing, auditory timing and gap detection skills of the children with AN were found as delayed in advanced degree. These findings may indicate that the AN children cannot perform temporal asynchrony. Our results may help to understand why the children with AN cannot manage the speech perception; and why they understand the speech after a few repeats.     

Laryngeal fiberscopic surgery — an alternate approach to microlaryngeal surgery

Microlaryngeal surgery (MLS) is difficult in patients with anaesthetic and cervical contraindications. An alternative approach is proposed here using a flexible laryngeal fiberscope and specially designed laryngeal instruments under local anaesthesia. Equipment and technique of the procedure is described. Indications and contraindications are highlighted based on our experience of 117 patients. Laryngeal fibrescopic surgery (LFS) was found to be a safer alternative. But this procedure cannot be used for all laryngeal pathologies.     

Treatment of military acoustic accidents with N-Acetyl-L-cysteine (NAC)

Objective: To study if the antioxidant (AO) N-Acetyl-L-cysteine (NAC) reduces the risk of hearing loss after acoustic accidents in humans.

Design: A retrospective, observational study.

Study sample: Personnel of the Swedish Armed Forces (SAF) exposed to military acoustic accidents during a 5 year period. Included in the study were 221 cases (mean age: 22.9 years). Most of the exposures, 84%, were weapon related. NAC (400?mg) was given directly after the accident in 146 cases; 75 had not received NAC.

Results: The prevalence of hearing thresholds ≥25?dB HL, and the incidence of threshold shifts ≥10?dB, was lower in the NAC group than in the non-NAC group directly after the noise exposure. The deterioration was temporary and not discernable a long time after the accident. The difference was most pronounced in the right ear. The risk reduction to get a temporary hearing loss (TTS), affecting one or both ears was 39% (significant) in the NAC group.

Conclusions: The study has demonstrated a significant reduction of the incidence of TTS by the use of NAC. Since cases of both permanent hearing loss (PTS) and noise-induced tinnitus are recruited from cases with TTS, the demonstrated risk reduction indicates a positive effect of NAC.     

Modulation of nerve fibers in the rat thyroarytenoid muscle following recurrent laryngeal nerve injury

Conclusion. The present study suggested that a high level of thymidine phosphorylase (TP) gene expression is significantly associated with favorable prognosis of patients treated with 5-fluorouracil (5-FU)-based chemotherapy. Further studies consisting of large series should be performed to confirm our present results. Background. Expression levels of the thymidylate synthase (TS) and 5-FU metabolic enzymes including dihydropyrimidine dehydrogenase (DPD), TP, and orotate phosphoribosyl transferase (OPRT), are reported to be associated with sensitivity to 5-FU-based chemotherapy in several cancers. Patients and methods. Intratumoral mRNA expression levels of TS, DPD, TP, and OPRT in pretreatment biopsy specimens were quantified in 27 patients with advanced oropharyngeal squamous cell carcinomas. Association of these expression levels with response to platinum and 5-FU-based chemotherapy and survival were analyzed statistically. Results. By Spearman's correlation analysis, significant correlation was observed between TS and TP (γ=0.51, p=0.018). While no correlation was observed between the tumor regression and expression of any of the genes investigated, significant association was observed between prognosis and mRNA expression levels of TS and TP. Multivariate Cox regression analysis revealed that TP mRNA expression level is a significant factor predicting prognosis (hazard ratio (HR) = ? 0.204, p=0.043).     

The accuracy of citation and quotation in otolaryngology/head and neck surgery journals1

A high rate of errors of citation and quotation has been reported in the publications of many medical specialties. The aim of this study was to determine the prevalence of citation and quotation errors in otolaryngology/head and neck surgery journals. A retrospective analysis was performed based on the first issue for 1997 of each of four journals: Laryngoscope;Annals of Otology, Rhinology and Laryngology;Clinical Otolaryngology; and Journal of Laryngology and Otology. A sample of 50 references from each journal was randomly selected and each was checked for accuracy against the original referenced paper. Citation errors were categorized as major, intermediate or minor and quotation errors as major or minor. Citation errors occurred in 37.5% of the references, 11.9% of which were considered major errors. Quotation errors occurred in 17%, with 11.1% major errors. This prevalence is similar to the established error rate in medical literature.     

Searching the literature using medical subject headings versus text word with PubMed

OBJECTIVE/HYPOTHESIS: This study was conducted to investigate the performance of two search strategies in the retrieval of information from the National Library of Medicine (NLM) on otolaryngology-head and neck surgery related conditions and diagnoses using PubMed. METHODS: Two search strategies-one based on the use of Medical Subject Headings (MeSH) and the second based on text word searching-were compared. RESULTS: The MeSH search provided a more efficient search than the text word search. CONCLUSIONS: Head and neck surgeons can most efficiently search the NLM using PubMed as a search engine by initiating the search with MeSH terms. Once a key article is identified, the searcher should use the "Related Articles" feature.     

A polymorphism in human estrogen-related receptor beta (ESRRβ) predicts audiometric temporary threshold shift

Objective: A non-synonymous single nucleotide polymorphism (rs61742642; C to T, P386S) in the ligand-binding domain of human estrogen-related receptor beta (ESRRβ) showed possible association to noise-induced hearing loss (NIHL) in our previous study. Design: This study was conducted to examine the effect of the ESRRβ rs61742642 T variant on temporary threshold shift (TTS). TTS was induced by 10?minutes of exposure to audiometric narrow-band noise centered at 2000?Hz. Hearing thresholds and distortion product otoacoustic emissions input output function (DP IO) at 2000, 3000, and 4000?Hz were measured before and after the noise exposure. Study sample: Nineteen participants with rs61742642 CT genotype and 40 participants with rs61742642?CC genotype were recruited for the study. Results: Participants with the CT genotype acquired a significantly greater TTS without convincing evidence of greater DP IO temporary level shift (DPTLS) compared to participants with the CC genotype. Conclusion: The results indicated that the ESRRβ polymorphism is associated with TTS. Future studies were recommended to explore molecular pathways leading to increased susceptibility to NIHL.