氨基糖甙类抗生素致聋家系线粒体DNA12S和16S rRNA基因突变分析

目的 研究线粒体rRNA基因突变与氨基糖甙类抗生素致聋遗传易感性的关系，为建立相应的基因诊断方法提供依据。方法 收集了五个有明确氨基糖甙类抗生素应用史的耳聋家系共27名成员的外周静脉血标本。从白细胞中提取DNA，PCR扩增线粒体DNA片段。Alw26I限制性内切酶分析和DNA序列分析检测A1555G点突变，并对其中一个家系进行了线粒体DNAl2S和16SrRNA基因的全序列分析。结果家系A．C．D和E的2l份样品均为A1555G点突变阳性，家系B的6份样品为A1555G点突变阴性。家系B线粒体DNAl2S和16SrRNA基因全序列分析显示该家系存在16SrRNA基因第2227位“AA”插入突变。结论 本研究发现了一个A1555G点突变阴性的氨基糖甙类抗生素致聋家系，说明线粒体DNA A1555G点突变不是氨基糖甙类抗生素遗传易感性唯一的分子基础，对氨基糖甙类抗生素致聋遗传易感性的预测仅检测A1555G点突变是不够的。应与mtDNA其它相关突变位点的检测结合起来。     

氨基糖甙类抗生素致聋家系线粒体DNA A1555G突变分析

目的 研究线粒体12S rRNA基因A1555G点突变与氨基糖甙类抗生素致聋遗传易感性的关系，为建立相应的基因诊断方法提供依据。方法 收集了五个有明确氨基糖甙类抗生素应用史的耳聋家系共23名成员的外周静脉血标本，从白细胞中提取DNA，PCR扩增线粒体DNA片段，限制性内切酶分析和DNA序列分析检测A1555G点突变。结果 五个家系有母系血缘关系的18份样品均为A1555G点突变阳性，5名配偶为A1555G点突变阴性。结论 线粒体DNA A1555G点突变是氨基糖甙类抗生素致聋遗传易感性最主要的原因，检测A1555G点突变对氨基糖甙类抗生素致聋遗传易感性的预测有重要意义。     

母系遗传药物性聋与非综合征性聋大家系与基因突变的研究

目的对一个氨基糖甙类药物性聋和非综合征聋的母系遗传性中国大家系进行遗传学分析,并发现全新的线粒体DNA C1494T突变.方法征集该家系中成员进行听力学检查,并收集提取DNA进行线粒体DNA PCR扩增分析,对其主要成员建立传代细胞系进行氨基糖甙类抗生素敏感试验和细胞氧消耗率检测.结果在没有接受氨基糖甙类抗生素时,一些母系遗传的成员表现为迟发/进行性听力下降,其程度不等,平均发病年龄自55岁(第2代)逐渐提前到10岁(第5代).氨基糖甙类抗生素可导致母系成员听力下降,而且接受药物的年龄似乎与听力下降程度有关.对该家系成员进行线粒体DNA测序发现高度保守的12S rRNA中1494位点C突变为T(C1494T),可以形成新的U1494-1555A碱基对,与耳聋有关的A1555G突变所造成的C1494-1555G碱基对结构相类似.当培养液中含有氨基糖甙类抗生素时,携带C1494T突变的4名听力遗传者和2名听力正常成员所建立的传代淋巴细胞系的细胞倍增时间显著延长,并且其细胞氧消耗总量显著降低.结论线粒体12S rRNA的A点是氨基糖甙类药物性聋的主要作用位点,而细胞核背景在氨基糖甙类药物性聋的发病中有重要作用,对C1494T突变的相关的耳聋发病中也有重要作用.     

线粒体DNA突变致聋家系检测及单倍型分析

目的 探讨母系遗传氨基糖甙类抗生素诱发致聋家系的线粒体DNA突变情况及其单倍型背景.方法 收集贵州遵义地区6个母系遗传非综合征性耳聋家系的临床资料及血液样本,经PCR-RFLP(polymerase chain re-action-restriction fragment length Polymorphism,聚合酶链反应-限制性片段长度多态)及测序技术检测线粒体DNA1555G突变,并通过对各家系线粒体DNA高变区序列测定及编码区限制性片段多态性分析以划分单倍型类群.结果 经酶切及测序证实其中4个家系存在线粒体DNA 1555G突变,分别属于A、D6、G及M*单倍型.结论 该地区线粒体DNA 1555G突变引起氨基糖甙类抗生素高度敏感致聋的家系发生率较高,线粒体DNA1555G突变致聋家系呈现不同的线粒体单倍型类型.     

线粒体基因组A1555G突变致非综合征性聋患者的临床表型分析

目的评估线粒体基因组（mitochondrial DNA，mtDNA）A1555G突变致非综合征性聋患者的临床表型及听力学特点。方法对经聚合酶链反应一限制性内切酶酶解法证实携带线粒体基因组A1555G突变的96例母系成员，进行病史调查和纯音听阈测试，并对性别、应用氨基糖甙类抗生素史、发病年龄等与耳聋程度的关系进行统计学分析。结果96例研究对象中耳聋患者与正常个体的性别分布均衡，34例有明确的氨基糖甙类抗生素用药史，67例耳聋患者中33例由氨基糖甙类药物耳毒性引起，26例用药后一周内发生耳聋，7例迟发。10个家系的平均耳聋外显率为68．8％。耳聋患者的临床表型多样，耳聋程度与应用氨基糖甙类药物时的年龄以及发病年龄相关，年龄越小，发生耳聋的程度越重；研究对象中年龄大于60岁的9例均为耳聋患者，但耳聋程度相对较轻。结论mtDNA A1555G突变本身不足以引起临床症状，氨基糖甙类药物和核基因在mtDNA A1555G突变的发病机制上起重要作用。携带mtDNA A1555G突变的成员年龄越小，越易出现听力下降，而且耳聋的程度越重。本组资料对耳毒性药物的风险提供了有价值的信息，从而提高氨基糖甙类药物使用的安全性，最终降低耳聋的发生率。     

非综合征型耳聋线粒体基因A1555G突变分析

目的通过分析内蒙古鄂尔多斯市特殊教育学校中非综合征型耳聋患者群体中线粒体基因12S rRNA A1555G突变,以探讨该群体与线粒体突变的关系。方法对鄂尔多斯市特殊教育学校102名非综合征型耳聋患者进行耳聋病因问卷调查、纯音听阈测试、声导抗测试及线粒体A1555G基因突变检测。结果102名非综合征型耳聋患者全部为感音神经性耳聋,54例有明确的氨基糖甙类抗生素用药史,7例（6.9%）存在线粒体基因A1555G位点突变。结论mtDNA 12S rRNA A1555G 在该研究群体中有较高的发生频率,携带有该突变的个体对氨基糖甙类抗生素的耳毒作用有高度易感性。     

巴龙霉素对携带线粒体DNA C1494T突变的细胞系生长的影响

目的用细胞学方法,分析线粒体DNA 12S rRNA基因中C1494T突变在氨基糖甙类抗生素聋发病机理中的作用.方法从携有线粒体DNA C1494T突变的母系遗传性氨基糖甙类抗生素性耳聋的中国大家系选择部分成员,另外从遗传背景相同的正常中国人群选择对照个体,分别建立淋巴细胞系;并通过细胞融合技术,将淋巴细胞系的线粒体分别融合到缺乏线粒体DNA的p0206细胞中,建立相应的转线粒体细胞系;家系成员与对照个体的淋巴细胞系和转线粒体细胞系,分别在不含/含有氨基糖甙类抗生素(巴龙霉素)的培养液中培养,以倍增时间(doublingtime,DT)作为细胞生长特性的评价标准,通过计算在正常和含有氨基糖甙类抗生素的培养液中倍增时间的比值,比较氨基糖甙类抗生素对细胞生长的影响.结果携有线粒体DNA C1494T突变家系成员较对照个体的淋巴细胞系的倍增时间比值平均增加了24%,但不同家系成员的细胞倍增时间比值的增加程度不同,自10%至50%不等;而当细胞核遗传背景相同后,家系成员较对照个体的转线粒体细胞系的倍增时间比值增长30%,并且来自不同表型的家系成员的细胞倍增时间比值基本相同.结论线粒体DNA C1494T突变可以造成细胞对氨基糖甙类抗生素的超敏性,但其效应要受到核基因的调控.     

与线粒体DNA A1 555G突变有关的非综合征型耳聋

在氨基糖甙类抗生素引起的耳聋中,有一部分患者表现为对这类抗生素的特殊敏感性,这类患者常常是由于其线粒体DNA的12s rRNA基因有A1555G的突变.后来又有研究发现,携带A1555G突变的人,可以在没有使用氨基糖甙类抗生素的情况下出现先天性或者后天性的非综合征型的耳聋,而且这种耳聋的临床表现具有多样性.这种临床表现的多样性可能是由于环境因素、核基因和线粒体的单体型的影响.本文简要介绍了这些因素对与mtDNA A1555G突变有关的耳聋的表现型的影响以及药物性耳聋发生的简要机理.     

一个氨基糖甙类药物致聋家系线粒体DNA全序列分析

目的 评估线粒体单倍型对一个氨基糖甙类药物致聋家系中12S rRNA A827G突变表型的影响.方法 用基因组DNA抽提试剂盒提取外周血DNA,PCR扩增家系成员mtDNA 12S rRNA基因进行A827G突变的测序验证,对携带A827G突变的家系先证者进行mtDNA全序列PCR扩增和测序分析,结果 与修正的剑桥参考序列比对,识别除A827G以外的突变位点.结果 5名母系成员mtDNA 12S rRNA序列分析均检测到A827G突变.与修正的剑桥参考序列及家系配偶相比,先证者的mtDNA全序列分析显示出独特的多态性改变,除已知的12S rRNAA827G突变外,另检测到24个碱基变异,其中12S rRNA基因A783C、G786C以及ND4基因C11720A突变(L319A)为首次发现.系统进化法分析显示,上述多态性位点均位于mtDNA非保守区域.结论 线粒体单倍型对该家系mtDNA A827G突变的表型表达无明显影响.     

携带线粒体基因突变非综合征型聋患者听力学和遗传学分析

目的　探讨修饰因子对线粒体A1555G突变相关非综合征型聋的影响。方法　对携带线粒体A1555G突变的27个家系69例非综合征型聋患者进行听力学和分子遗传学评估。结果　27个家系平均听力损失患者发病年龄11.96岁，排除氨基糖甙类抗生素接触史者，年龄上升为15.21岁；家系3代内平均听力损失外显率40.96%，排除有氨基糖甙类抗生素接触史者，外显率降至33.45%。27个家系分属8种不同单倍型，并携带tRNAIleA4317G、tRNAGlnC4387T、tRNASer（UCN）T7492C和tRNAThrC15910T四个继发突变。检测到2例GJB2 235 delC纯和突变，1例GJB2 235 delC杂合突变。此外，患者主要表现为轻、中度高频听力损失类型，多为语后聋。结论　氨基糖甙类抗生素、线粒体单倍型及继发突变、GJB2和发病年龄等因素可能参与了携带线粒体A1555G突变者的表型修饰。     

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.     

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.     

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.     

Tongue Base Reduction with Temperature-controlled Radiofrequency Volumetric Tissue Reduction for Treatment of Obstructive Sleep Apnea Syndrome

In recent years a considerable effort has been made to establish the use of different surgical techniques for the treatment of obstructive sleep apnea syndrome (OSAS). Nevertheless, treatment of hypopharyngeal obstruction due to tongue base hypertrophy remains in many ways an unsolved problem. The aim of this study was to evaluate the safety and efficacy of tongue base reduction with temperature-controlled radiofrequency volumetric tissue reduction in the treatment of OSAS. Twenty patients with OSAS and tongue base hypertrophy were treated with radiofrequency tissue ablation. An intensified treatment protocol was used, delivering 2,800 J per treatment session under local anesthesia. Two nights of polysomnography testing were performed before and after treatment. Daytime sleepiness, snoring and postoperative morbidity were assessed using questionnaires. Mean respiratory disturbance index (RDI) was reduced from 32.1 to 24.9/h after a mean of 3.4 treatment sessions. Six patients (33%) were cured after the procedure (reduction in RDI of &#83 50% and a postoperative RDI of <15/h) and ten (55%) showed an improvement of >20% in their RDI. Daytime sleepiness and snoring improved significantly. Peri- and postoperative morbidity was low; one severe complication occurred (tongue base abscess). We were able to achieve similar cure and responder rates to those reported in a recently published pilot study but with a reduced number of treatment sessions. We believe that this technique may improve patient acceptance and have beneficial cost implications.     

A simple objective evaluation and grading for facial paralysis outcomes

Matrix metalloproteinase (MMP)-2 and -9 degrade type IV collagen, which is one of the major components of the basement membrane in normal tissue and expressed in the surroundings of the cancer nest in squamous cell carinoma. The degeneration of type IV collagen is an essential step in the metastasis to lymph nodes and distant organs. In this study, we examined MMP-2 and -9 levels of cancer tissue and serum obtained from patients with head and neck squamous cell carcinoma (HNSCC) in order to evaluate the relationship between the clinicopathologic features and MMPs. We examined the production of MMP-2 and -9 in cancer tissue homogenates of 73 patients who had HNSCC and the serum MMP levels of 16 patients with HNSCC and 8 healthy volunteers. We also studied the localization of MMP-2 in the carcinoma using an immunohistochemical approach. The concentrations of MMP-2 and -9 in the tissue homogenates and serum were measured by means of a sandwich enzyme immunoassay using a monoclonal antibody. Immunohistochemical analyses were performed with monoclonal antibody to MMP-2. The concentration of MMP-2 in the tumor tissue homogenates was unrelated to tumor size, but that in patients with lymph node metastases was significantly higher than in those without lymph node metastases. The concentration of MMP-9 was unrelated to lymph node metastasis and tumor size. The levels of both MMP-2 and -9 in serum were unrelated to lymph node metastasis. Immunohistochemistry indicated that MMP-2 was mainly expressed in cancer cells. Because MMP-2 degrades type IV collagen, the level of MMP-2 in carcinomas may be a useful indicator of the degree of invasion and metastasis.     

A case of cortical deafness and anarthria

The nasal epithelium protects the underlying tissue from damage. Epithelial cell growth is controlled by epidermal growth factor (EGF) and is possibly affected by toxic proteins, e.g. eosinophil cationic protein (ECP). The aims of this study were to examine nasal fluid epithelial cell counts and their relations to EGF, eosinophils and ECP in 23 patients with seasonal allergic rhinitis and 20 healthy controls. Nasal fluid epithelial cell counts were lower in patients than in controls. EGF levels did not differ between patients and controls, and correlated with epithelial cell counts in controls but not in patients. Eosinophils and ECP were higher in patients than in controls, but did not correlate with epithelial cell counts. The role of growth factors, such as EGF, in regulating epithelial cells merits further study.     

Lack of significant estrogen and progesterone receptor expression in nasal telangiectasias in hereditary hemorrhagic telangiectasia: an immunohistochemical analysis

Obstructive sleep apnea syndrome (OSAS) is characterized by snoring and apnea during sleep leading to decreased oxygen saturation and disturbed sleep, excessive daytime sleepiness and neuropsychological disturbances. This study investigates cognitive neuropsychological abilities in a group of 53 OSAS patients before and after treatment with uvulopalatopharyngoplasty. General intellectual ability, verbal learning and memory as well as executive functioning were measured at baseline and 6 months postoperatively. After surgery there were significant improvements in verbal learning and memory (mean change - 39, SD 57.3, p <0.001), recall (mean change - 24.3, SD 39.3, p <0.001) and executive functioning (as assessed by percentage of errors on the Wisconsin Card Sorting Test; mean change-9.1, SD 15.7, p <0.001). These improvements were in accordance with improvements in the degree of sleep apnea, the oxygen desaturation index (mean change -9.7, SD 15.9, p <0.001) and arterial minimum oxygen saturation (mean change 4.5%, SD 10.2%, p <0.01). Surgical treatment seems to improve verbal learning, memory and recall and executive functions in parallel with better oxygenation in OSAS.