畸变产物耳声发射的产生源的研究

为了澄清畸变产物耳声发射(DPOAE)产生源的机制,本研究首先采用固定刺激声频率比,交替加抑制声和对没有抑制声作用下的DPOAE信号进行分解的方法进行对比研究,得出DPOAE的产生源至少具有两个或两个以上,并具有不同的产生性质的仞步结论.在此基础上,采用固定刺激声频率f2和扫描刺激声频率f1,逐步改变抑制声强度的方法.结果证明:DPOAE信号是由双源产生的,并且分别具有两种不同的性质.位于刺激频率f1和f2的最大交叠区且靠近f2位置处的产生源是主要的源并具有非线性相位的性质,产生具有较短潜伏期的信号.位于2f1-f2频率附近有另外一个产生源,该源产生的DPOAE信号具有线性相位性质,并具有较长的潜伏期.耳道中检测到的DPOAE是由两个不同的源所产生的DPOAE信号之和.     

粉尘螨变应原第5组分基因克隆及分子特征分析

目的 获得粉尘螨变应原第5组分的编码基因(Der f5)并了解其分子特征.方法 用RNAiso试剂盒提取粉尘螨总RNA,根据GenBank已公布的Der f5核酸序列设计引物,用RT-PCR扩增获得其编码基因,插入pMD19-T Simple载体进行序列测定和分析.结果 获得的Der f5基因与参考序列(GenBank AY283283)同源性达97.8%,含1个完整的开放阅读框架(ORF),由132个氨基酸组成,信号肽位于1～19AA、跨膜区域位于1～19AA,为细胞外疏水性蛋白.二级结构由延伸主链(1.52%)、无规则卷曲(7.58%)和α螺旋(90.91%)组成.具有酪蛋白激酶Ⅱ磷酸化位点2个.其氨基酸序列与屋尘螨变应原第5组分相似率为78%.结论 成功克隆了 Der f5,并初步预测得其分子特征.     

不同尘螨过敏原诱导组胺释放能力分析

目的:研究用肥大细胞组胺体外定向释放模型分析重组尘螨过敏原Der f 1和Der f 2的致敏差异性.方法:用重组尘螨致敏原Der f 1、 Der f 2免疫C57/BL6小鼠,收集小鼠腹腔致敏肥大细胞(PMC),在96酶标板孔中分别按不同比例混合尘螨致敏组分诱导PMC定向释放组胺,荧光法检测其释放水平.结果:Der f 1、 Der f 2及两者的混合物都能引起PMC释放组胺,其致敏效果Der f 2明显高于Der f 1,Der f 1、 Der f 2混合致敏组胺释放量未见高于单组分致敏者.牛奶和虾的粗提液与空白对照不能引起PMC组胺的明显释放.结论:尘螨混合组分未能引起比单独Der f 1或Der f 2强的组胺释放,两者间不存在协同效应.组胺释放量随Der f 2比例升高而升高,推测在尘螨过敏中Der f 2起主要作用.尘螨与牛奶、虾之间不存在交叉反应.     

不同类型霍奇金淋巴瘤EBV检测的原位杂交和免疫组化方法比较

目的 探讨EBER原位杂交和免疫组化EnVision两步法在检测不同类型霍奇金淋巴瘤(Hodgkin's lymphoma,HL)中EBV的表达和意义.方法 收集68例不同类型HL标本(结节硬化型38例、混合细胞型18例、淋巴细胞丰富型7例、淋巴细胞消减型5例),石蜡切片后,分别采用EBER原位杂交法检测EBV编码的mRNA(epstein barr encoded RNAs1,EBER1)以及免疫组化EnVision两步法检测EBV潜伏膜蛋白1(laten mbmbrane proteins,LMP1)在不同类型HL中的表达.结果 68例标本中,免疫组化EnVision两步法检测结果 总阳性率为36%(25/68),其中结节硬化型为23%(9/38),混合细胞型为66%(12/18),淋巴细胞丰富型和淋巴细胞消减型分别为28%(2/7)和40%(2/5);原位杂交检测结果 总阳性率为55%(38/68),其中结节硬化型为42%(16/38),混合细胞型为88%(16/18),淋巴细胞丰富型和淋巴细胞消减型分别为42%(3/7)和60%(3/5).结论 在对不同类型HL的EBV检测中,EBER原位杂交方法 比免疫组化EnVision两步法检出率更高,定位更清晰,同时也更具特异性和敏感性.     

股骨远端骨折两种固定方法对比研究

目的 对比应用逆行交锁髓内钉(GSH)和动力髁螺钉(DCS)内固定治疗股骨远端骨折的效果.方法 采用回顾性研究方法对我院自2000年8月～2004年10月治疗的54例股骨远端骨折病例进行对照研究,按A0分类:A1型17例,A2型14例,A3型11例,B1型2例,C1型6例,C2型3例,C3型1例.其中,DCS内固定30例,GSH固定24例.分组统计手术时间,出血量,骨折愈合时间,并发症,膝关节功能.结果 所有病例经5月～2年随访,平均9个月;骨折愈合时间为4.6月(4～9月).DCS固定组平均手术时间1.5小时(1～2.5小时).出血量105 ml(50～200 ml),骨折愈合时间平均4.7月(4～8月),并发症发生5例(发生率16.7%),根据Kolmert膝关节功能评分,优20例,良6例,可4例,优良率为86.6%.GSH固定组手术时间1.8小时(1.5～3.5小时).术中出血量平均120 ml(100～250 ml),平均骨折愈合时间5.1个月(4.5～9个月),并发症发生5例(发生率28%),根据Kolmert膝关节功能评分标准,优15例,良7例,可2例,优良率为91.7%.两组比较,结果无显著差异(P＞0.05) 结论 逆行带锁髓内钉(GSH)及动力髁螺钉(DCS)均是治疗股骨远端骨折的较好方法,但各有其最佳适应症.选择好适应症以及术者技术熟练有利于骨折愈合及关节功能恢复.     

三个角膜营养不良家系的TGFBI基因突变

目的 筛查3个角膜营养不良家系患者TGFBI基因突变.方法 采集患者外周静脉血,提取基因组DNA,采用直接测序对TGFBI基因全部17个外显子以及外显子内含子拼接部进行序列分析.结果 3个家系中两个家系表型为格子样角膜营养不良1型(1attice corneal dystrophy type I,LCD I)和格子样角膜营养不良3A型(lattice corneal dystrophy type ⅢA,LCDⅢA),另外1个家系为Avellino角膜营养不良(avellino corneal dystrophy,ACD).在两个LCD家系中分别检出编码子R124C和H626R突变,而在ACD家系中检出R124H突变.结论 TGFBI基因是引起角膜营养不良的致病基因.R124和H626是角膜营养不良的突变热点.     

150种过敏原在过敏性疾病中的阳性率分析

目的 通过检测过敏性疾病患者血清中过敏原特异性抗体水平,了解过敏原与常见过敏性疾病的相关性,为不同过敏性疾病过敏原检测重点以及选择合适的预防和治疗方案提供科学依据.方法 将患者分成三组,采用荧光酶联免疫法,用ImmunoCAP过敏原检测试剂检测150种过敏原的特异性IgE(sIgE)水平,统计每种过敏原的阳性检出例数,采用SPSS统计软件对三组阳性率进行比较和分析.结果 过敏原阳性率在三组过敏性疾病之间差异有统计学意义的过敏原有17种(P≤0.05),差异无统计学意义的有133种(P＞0.05).呼吸道过敏性疾病和呼吸道合并皮肤混合型过敏性疾病两者都比单纯皮肤过敏性疾病对h1、h2、d202、d203过敏原敏感(P＜0.05);呼吸道合并皮肤混合型过敏性疾病比单纯的呼吸道过敏性疾病和单纯的皮肤过敏性疾病对m2、f79、c1、c2过敏原敏感(P＜0.05),比单纯呼吸道过敏性疾病对f427、f17、fx15、f84、f95、f35、f85、k75过敏原敏感(P＜0.05),比单纯皮肤过敏性疾病对e5过敏原敏感(P＜0.05).结论 临床上除了应对主要常见过敏原进行检测和筛查外,还应根据患者过敏性疾病类型及过敏原接触史等情况,将三组阳性率比较差异有统计学意义的17种过敏原纳入检测筛查范畴.建议在诊治呼吸道合并皮肤混合型过敏性疾病时要特别注意筛查m2、c1、c2、f79过敏原.     

2009-2015年河北省儿童流感病原学分析

目的 分析2009-2015年河北省儿童流感样病例(influenza like illness,ILI)流感病原学特征,为河北省儿童流感的防控提供科学依据.方法 采集河北省流感监测哨点医院就诊的儿童ILI咽拭子标本,采用RT-PCR方法进行流感病毒核酸检测.结果 共采集咽拭子标本28 932例,检出流感病毒阳性标本5057例(阳性率为17.48％).按年度分析,6个年度流感病毒检出率依次为32.56％、9.53％、15.07％、12.29％、11.32％和18.81％,2009-2010年度显著高于其他年度(P＜0.05).以B型流感病毒为优势型的年度有两个(2011-2012、2013-2014年度),其他年度为甲型H1N1和季节性H3N2流感交替流行或共同流行.年龄分布中,1岁以下年龄组检出率最低(7.74％),7-14岁年龄组最高(26.01％),检出率随年龄的增大而增高.季节分布显示,河北省流感为冬春季流行,呈单峰型,A型流行形成的峰时间靠前.结论 2009-2015年度河北省儿童中存在甲型H1N1、B型和季节性H3N2流感病毒的流行,不同年度有不同的流行优势型和流行特征.     

罗布麻的民族植物学与资源开发利用

罗布麻是我国值得重视的资源植物,属于夹竹桃科(Apocynaceae),一般分类为两个属三个种,通常用大花白麻[Poacynum hendersonii(H-ook.f.)Wood son]和红麻(罗布麻Apocynum Ve-netum L.)经考证在我国有着悠久的应用历史,在历代人民的经济生活和医药活动中有一定的价值。特别是在少数民族地区的应用。     

14—4 液体扩散系数D的证明

扩散过程是物质的传递过程,一般来说,物质的传递可由浓度梯度、电场或其它力场引起,在每种情况下,推动物质传递的力都可看作一种势的负梯度,与扩散现象相关的势是化学势(μ),即化学势的负梯度等于作用于单位质量(1摩尔)物质上的力,因此作用在一个分子上的扩散推动力。 F=-1/Noμ/X 分子在F作用下在溶剂中沿X方向运动时要受到粘滞阻力f的作用,根据斯托克司定     

The nature of the pi1 colour mechanism of W.S. Stiles.

The ppi1 colour mechanism was isolated by means of Stile's auxiliary field technique: that it is pi1 which is isolated is proven by both test and field action spectra. 2. The fundamental mechanisms of human trichromatic colour vision must satisfy Grassman's law of additivity. The hypothesis that pi1 is one of the three fundamentals is tested by experiments in which pairs (u1, u2) of monochromatic adapting fields are mixed 3. When two fields with wave-lengths in the neighbourhood of its primary mode (mu1, mu2 less than or equal to 500 nm) are combined, pi1 is field-additive, consistent with the hypothesis that this portion of the pi1 action spectrum is that of the short-wave-length-sensitive photoreceptors. 4. When a short-wave-length adaptation field (mu1 less than or equal to 500 nm) is mixed with a longer wave-length field (mu2 greater than or equal 550 nm) i1 is strongly non-additive. This result proves that the long-wave-length portion of the pi1 field spectrum is generated at least in part by a signal originating in the long- or middle-wave-length sensitive cones. 5. Analysis of the additivity failures supports a model of pi1 in which the signal to be detected is generated in the short-wave-length cones, and must pass serially through two gain stages: the gain in the first stage is controlled by the short-wave-length cones alone; the gain in the second stage is controlled by a signal originating in the middle, or long-wave-length cones, or both.     

大鼠前额叶皮层多通道局部场电位和锋电位的频谱相干对工作记忆事件的编码

目的 基于大鼠前额叶皮层多通道局部场电位和锋电位的频谱相干编码,研究不同模态的神经信号如何相互协同编码工作记忆行为事件.方法 应用Cerebus多通道信号采集系统,记录大鼠Y迷宫工作记忆行为事件中在体前额叶皮层上同时记录的2类不同模态的多通道神经信号:连续的多通道局部场电位(LFPs)和离散的多通道锋电位(Spikes...     

Improving the detection of evoked responses to periodic stimulation by using multiple coherence--application to EEG during photic stimulation

The coherence between the stimulation signal and the electroencephalogram (EEG) has been used in the detection of evoked responses. However the detector's performance depends on both the signal-to-noise ratio (SNR) of the responses and the number of data segments (M) used in coherence estimation. In this work, a technique for detecting evoked responses was developed based on the extension to the multivariate case of this coherence. Thus, instead of using the EEG collected at a unique region, the estimation is proposed using two EEG derivations. As for the univariate case, this multiple coherence is independent of the stimulation signal. In addition, considering equal SNR in both signals, the detection rate with this multiple coherence is always greater than that one using only one signal. This was verified in Monte Carlo simulations, which also showed that a superior performance is still expected in practical situations, when a smaller SNR is found in the second signal. The results with EEG from 12 normal subjects during photic stimulation confirm this better performance. Since the proposed technique allows a higher detection rate without the need of increasing M, it permits evoked responses to be detected faster, which is very useful during monitored surgeries.     

EEG activity during the performance of complex mental problems.

This study investigated differences in cognitive processes related to problem complexity. It was assumed that these differences would be reflected in respondents' EEG activity--spectral power and coherence. A second issue of the study was to compare differences between the lower (alpha(1) = 7.9-10.0 Hz), and upper alpha band (alpha(2) = 10.1-12.9 Hz). In the first experiment two well-defined problems with two levels of complexity were used. Only minor differences in EEG power and coherence measures related to problem complexity were observed. In the second experiment divergent production problems resembling tasks on creativity tests were compared with dialectic problems calling for creative solutions. Differences in EEG power measures were mainly related to the form of problem presentation (figural/verbal). In contrast, coherence was related to the level of creativity needed to solve a problem. Noticeable increased intra- and interhemispheric cooperation between mainly the far distant brain regions was observed in the EEG activity of respondents while solving the dialectic problems. These results are explained by the more intense involvement of the long cortico-cortical fiber system in creative thinking. Differences between the lower and upper alpha band were significant for the power and coherence measures. In Experiment 2, fewer differences were observed in power measures in the upper alpha band than in the lower alpha band. A reverse pattern was observed for the coherence measures. These results hint to a functional independence of the two alpha bands, however, they do not allow to draw firm conclusions about their functional meanings. The study showed that it is unlikely that individuals solve well- and ill-defined problems by employing similar cognitive strategies.     

Responses of inferior colliculus neurons to double harmonic tones

The auditory system can segregate sounds that overlap in time and frequency, if the sounds differ in acoustic properties such as fundamental frequency (f0). However, the neural mechanisms that underlie this ability are poorly understood. Responses of neurons in the inferior colliculus (IC) of the anesthetized chinchilla were measured. The stimuli were harmonic tones, presented alone (single harmonic tones) and in the presence of a second harmonic tone with a different f0 (double harmonic tones). Responses to single harmonic tones exhibited no stimulus-related temporal pattern, or in some cases, a simple envelope modulated at f0. Responses to double harmonic tones exhibited complex slowly modulated discharge patterns. The discharge pattern varied with the difference in f0 and with characteristic frequency. The discharge pattern also varied with the relative levels of the two tones; complex temporal patterns were observed when levels were equal, but as the level difference increased, the discharge pattern reverted to that associated with single harmonic tones. The results indicated that IC neurons convey information about simultaneous sounds in their temporal discharge patterns and that the patterns are produced by interactions between adjacent components in the spectrum. The representation is "low-resolution," in that it does not convey information about single resolved components from either individual sound.     

Coherence at 16-32 Hz can be caused by short-term synchrony of motor units

Time- and frequency-domain measures of discharge times for pairs of motor units are used to infer the proportion of common synaptic input received by motor neurons. The physiological mechanisms that can produce the experimentally observed peaks in the cross-correlation histogram and the coherence spectrum are uncertain. The present study used a computational model to impose synchronization on the discharge times of motor units. Randomly selected discharge times of a unit that was being synchronized to a reference unit were aligned with some of the discharge times of the reference unit, provided the original discharge time was within 30 ms of the discharge by the reference unit. All time-domain measures (indexes CIS, E, and k') were sensitive to changes in the level of imposed motor-unit synchronization (P < 0.01). In addition, synchronization caused a peak between 16 and 32 Hz in the coherence spectrum. The shape of the cross-correlogram determined the frequency at which the peak occurred in the coherence spectrum. Further, the magnitude of the coherence peak was highly correlated with the time-domain measures of motor-unit synchronization (r2 > 0.80), with the highest correlation occurring for index E (r2 = 0.98). Thus the peak in the 16- to 32-Hz band of the coherence spectrum can be caused by the time that individual discharges are advanced or delayed to produce synchrony. Although the in vivo processes that adjust the timing of motor-unit discharges are not fully understood, these results suggest that they may not depend entirely on an oscillatory drive by the CNS.     

Gentamicin, tobramycin, and sisomicin disc susceptibility tests. Revised zone standards for interpretation

Studies were undertaken to reevaluate interpretive zone standards for gentamicin and tobramycin disc tests. Disc tests with an investigational aminoglycoside, sisomicin, were also evaluated. The data suggest modification of zone standards for gentamicin disc tests to R (resistant) less than or equal to 12 mm and S (susceptible) greater than or equal to 16 mm. Currently recommended standards for tobramycin disc tests (R less than or equal to 12 mm and S greater than or equal to 15 mm) were found to be satisfactory. For 10-microgram sisomicin discs, zone standards of R less than or equal to 12 mm and S greater than or equal to 15 mm were also appropriate. Although gentamicin is structurally similar to sisomicin, it was less active against Pseudomonas aeruginosa. The activity spectrum of sisomicin against the collection of 470 bacterial isolates studied more nearly resembled that of tobramycin. Data analysis suggested that tobramycin disc tests might be used to predict susceptibility to sisomicin. However, these two drugs differ in their susceptibilities to aminoglycoside-inactivating enzymes produced by some resistant strains. In those institutions where such strains are endemic, the class concept of disc testing may not be applicable.     

Differences between K channels in motor and sensory nerve fibres of the frog as revealed by fluctuation analysis

Differences between K channels in the nodal membrane of sensory and motor myelinated nerve fibres of the frog were investigated by fluctuation analysis. Spectral densities, S(f), between 3 Hz and 5 kHz were determined from K-current fluctuations measured between 145 and 460 ms after the onset of depolarizations V between 16 and 80 mV. Fits by the sum of a 1/f component and Lorentzian spectra corresponding to Hodgkin-Huxley n4-kinetics gave significant deviations from the measured spectra. The best fit was obtained by: S(f) = S1/[1+(f/fc)1.5]+S2. The first term can be interpreted as a diffusion spectrum which would originate from gating of K channels governed by an electrodiffusion process. To describe the spectral density at frequencies above 1 kHz it was necessary to add the plateau S2. Time constants taun* = 1/(2pifc) are roughly equal to the conventional Hodgkin-Huxley time constant taun only for pulses V < 40mV. At higher depolarizations taun increases with increasing depolarization in contrast to taun. The variance, var, of conductance fluctuations was determined by integration of the first component of S(f). From var, the probability of the open channel state, and the steady-state K current the single-channel conductance gamma and the number N of K channels per node were calculated; all parameters were corrected for K accumulation during depolarizing pulses. gamma and N were found to be only weakly voltage-dependent. The mean values over all voltages are for motor fibres: gamma=2.7 pS, N = 5.7 x 10(4), and for sensory fibres: gamma = 4.6 pS, N = 5.2 x 10(4). The results suggest two different kinds of K channels in motor and sensory nerve fibres.     

细胞内自由钙离子浓度变化的时-频分析

了解细胞内自由钙离子浓度([Ca~(2+)]_i)的变化规律是探知细胞乃至相关生物组织生存及健康状况的手段,而采用时-频分析方法则可获得其变化规律中较多的深层次信息.为了更好了解癌细胞与正常细胞内[Ca~(2+)]_i变化规律间的差异以及各自的特征,选取3种癌细胞和4种正常细胞作为实验对象.首先,用荧光试剂对各细胞样品进行负载,再用激光扫描共聚焦显微镜对细胞内的荧光强度进行测量,以获得细胞内[Ca~(2+)]_i的时域数据;接着,对时域数据进行时-频分析,并给出时-频分布函数的等值线图.结果表明,虽然癌细胞和正常细胞内[Ca~(2+)]_i的变化在时-频域内均有连续出现和离散出现的两类谱带,但癌细胞与正常细胞间的差异却是明显的.差异主要表现在:癌细胞中连续谱带的宽度大于正常细胞连续谱带的宽度,癌细胞中只有1条离散谱带,而正常细胞中却有2条离散谱带;不同癌细胞中离散谱带的中心频率相同,而不同正常细胞离散谱带的中心频率却各不同;癌细胞离散谱带中各频谱分量的相对振幅大于正常细胞各频谱分量的相对振幅.这些结果既为鉴别癌细胞提供一个新的指标,也为认识不同正常细胞的健康状况提供新的参考数据,同时可为电磁波的生物学窗效应机理研究奠定生物学自身的内禀依据.